JP2021133367A - High-pressure washing system and method for coating film removal - Google Patents

Abstract

To improve the detoxication degree of a waste water by collecting a high pressure-injected wash water as a waste water in a technique for peeling off the existing coating film from the surface of a structure by high pressure-injecting the wash water to wash the structure.SOLUTION: A high-pressure washing system for removing the existing coating film from the surface of a structure by high pressure-injecting a wash water to wash the surface of the structure has a unit which treats the high pressure-injected wash water as a harmful material-including waste water. The unit comprises: a flocculation tank 240 in which the prescribed harmful materials in the waste water are flocculated by adding at least one among a heavy metal insolubilization agent and adsorbent such as active carbon powders to the waste water; and a filtration part 242 sorting the waste water into the harmful material as a solid and the post-filtration waste water in which the harmful material is removed.SELECTED DRAWING: Figure 19

Description

The present invention relates to a technique for injecting cleaning water at a high pressure to remove an existing coating film from a base material of a structure for cleaning. In particular, the cleaning water injected toward the structure is recovered as waste water. It is about technology to improve the degree of detoxification of it.

In a specific case, for example, since it was confirmed that harmful substances such as lead are present in the existing coating film adhering to the base material of the structure, the notification dated May 30, 2014 from the Ministry of Health, Labor and Welfare is followed. When it is necessary, buildings (houses, buildings, etc.), steel towers (for example, power transmission towers, communication steel towers, etc.), which are elongated structures constructed using an iron frame structure, civil engineering structures In order to repaint the surface of a structure or structure such as (bridge, etc.), ship, vehicle (automobile, train, etc.), airplane, etc., the existing coating film already adhered to the surface is applied to the surface (base material) of the structure. A type of construction is performed in which new paint is applied on the same surface of the structure.

Here, as a method for peeling off the existing coating film, for example, as described in Patent Document 1, there are a physical method and a chemical method. Physical methods include hand tools such as scrapers, electric rotary tools that rotate removers such as wire brushes using an electric motor, air rotary tools that rotate similar removers using an air motor, and high-pressure water injectors. This is a method in which an operator uses a peeling machine or the like to peel off an existing coating film from a structure.

On the other hand, the chemical method is a method in which a release agent containing a chemical is applied to an existing coating film to dissolve or swell the existing coating film, thereby peeling the existing coating film from the structure. This method is also referred to as a wet coating film removing method using a coating film removing agent, that is, a wet peeling method, as described in Patent Document 1, for example.

There are various demands for the wet peeling method. For example, a request that the release agent has a small adverse effect on the environment (improvement of environmental response ability), a request that the release agent has a small adverse effect on the health of the worker (prevention of damage to the health of the worker), work There is a demand for high efficiency when a person performs a peeling work (improvement of the peeling work of a worker), a demand for a high ability of a peeling agent to peel an existing coating film (improvement of peeling performance of a peeling agent), etc. do.

Regarding the wet peeling method, Patent Document 1 describes the film thickness of the peeling agent layer (hereinafter, also referred to as “peeling agent layer” or “peeling agent coating film”) to be adhered on the existing coating film (hereinafter, “removing agent coating film”). For the purpose of increasing the "coating film thickness"), a surfactant is added to the release agent as a foaming agent before dipping the release agent, and the release agent is stirred in that state to form a release agent. It discloses a technique for mixing minute bubbles. If the coating thickness of the release agent applied on the existing coating film is increased by dipping and the coating amount is increased, there is a possibility that the demands for improving the efficiency of the peeling work and the peeling performance may be satisfied.

Further, Patent Document 2 discloses a technique of using an airless spray coating machine in order to expand the coating area of the release agent. However, Patent Document 2 does not disclose or suggest that it is useful to use an airless spray coating machine to increase the coating thickness of the release agent.

By the way, the present inventor has the practicality of carrying out the above-mentioned physical removal method alone for peeling the coating film, that is, without carrying out the above-mentioned wet peeling method, that is, applying the release agent to the existing coating film. It was tested whether the existing coating film could be satisfactorily peeled off from the structure even if the above-mentioned physical removal method was carried out alone without applying it on top.

Here, just in case, to explain the definitions of the respective terms "peeling" and "removal" as important terms, both terms mean that the coating film separates from the structure in a broad sense. They have in common with each other in terms of points. However, the term "peeling" does not limit the form of separation in that the form of separation is "peeling" the coating film (eg, active film) from the surface of the structure in a tight adhesion state. Different from the term "removal".

In that sense, the term "removal" constitutes a superordinate concept to the term "peeling". Therefore, in a broad sense, the term "removal" includes the term "peeling" and also means separation other than the form of "peeling". For example, when the coating film is not strong on the surface of the structure but is barely adhered to the surface of the structure due to softening, shrinkage, floating or peeling (for example, a deteriorated coating film). In addition, separating the coating film from the surface of the structure is more appropriate to be called "removal" than "peeling". Further, the phenomenon in which the peeling of the coating film and the mere separation of the coating film occur together may be generically referred to by the term "removal".

As a result of the above test, the present inventor has confirmed that under specific test conditions, when the physical removal method is carried out independently regardless of the type, almost all of the existing coating film is removed. It means that it could not be efficiently peeled off from the structure. Therefore, the practicality of carrying out the above-mentioned physical removal method alone for peeling the coating film could not be confirmed at least in this test.

Specifically, the present inventor tested the high-pressure cleaning method alone as a physical removal method under specific test conditions. As the specific test condition, there was an injection pressure condition that the injection pressure of the washing water from the spray gun was about 180 kgf / cm ^2. In this test, although the dirt on the surface of the existing coating film was removed, the existing coating film itself was severely deteriorated, and only the portion that had already partially floated from the substrate was peeled off. Therefore, the practicality of carrying out the high-pressure cleaning method alone for peeling the coating film could not be confirmed, at least in this test.

In addition, the present inventor has changed the above-mentioned injection pressure to ultra-high ^{pressure, for example, about 800 to about 1,500 kgf / cm 2, for the practicality of carrying out the high-pressure cleaning method alone.} I realized that if I did, it could be affirmed. However, the present inventor has also recognized that there may be new problems when implementing this ultra-high pressure cleaning method.

That is, the present inventor may have a physical danger to the worker if the ultra-high pressure washing water collides with the worker, and the amount of the ultra-high pressure washing water scattered after injection exceeds the controllable range. There is a possibility that the size of the coating piece that is peeled off from the base material of the structure due to collision with the ultra-high pressure washing water is large enough to exceed the controllable range, and the amount of scattering of the coating piece can be controlled. He realized that there was a possibility that the number would exceed the range.

Further, when the physical removal method is carried out in combination with the wet peeling method as the previous step, the present inventor has a method of using an electric rotary tool, a method of using an air rotary tool, and a method of using the air rotary tool as the physical removal method. Tests were also conducted to evaluate the practicality of each of the high-pressure cleaning methods (including ultra-high pressure cleaning).

Based on the results of the test, the present inventor mutually evaluated the above-mentioned three types of physical removal methods from the viewpoint that the base material of the structure is not easily damaged during the physical removal work of the existing coating film. We recognized that the high pressure cleaning method was superior to other methods.

Several conventional examples of a high-pressure cleaning method for removing a coating film are disclosed in Patent Document 3-7. Regarding the gun, a conventional example of a coating gun that injects paint at high pressure is disclosed in Patent Document 8, and a conventional example of a water jet gun for peeling a coating film is disclosed in Patent Document 9, which injects high-pressure water. A conventional example of a cancer is disclosed in Patent Document 10.

Japanese Unexamined Patent Publication No. 62-20575 Japanese Patent No. 6442101 Japanese Unexamined Patent Publication No. 9-170337 JP-A-2009-179860 Japanese Unexamined Patent Publication No. 2015-223531 Japanese Unexamined Patent Publication No. 2005-161286 Japanese Unexamined Patent Publication No. 2001-212298 JP-A-2002-096006 Japanese Unexamined Patent Publication No. 2020-040300 Japanese Unexamined Patent Publication No. 8-066644

Against the background of the above-mentioned prior art related to wet peeling, the present inventor has four requests mentioned above, that is, a request for improving the ability to respond to the environment, a request for preventing health damage to workers, and a request for peeling work. In order to simultaneously achieve at least two requests for efficiency and improvement of the release performance of the release agent, the release agent should not be scattered when the release agent is applied, and the existing coating film should be treated. I realized that it is important to increase the coating film thickness and thus the coating amount of the release agent without dripping from the existing coating film on the surface.

Then, the present inventor uses the wet release agent coating technique to prevent the release agent from scattering when the release agent is applied, and to allow the release agent applied on the surface of the existing coating film to drip from the existing coating film. Research and development was carried out to make it possible to maximize the coating film thickness of the release agent and increase the coating amount and thus the coating amount at the same time.

Against these circumstances, one aspect of the present invention is a wet release agent coating technique, which prevents the release agent from scattering when the release agent is applied and is applied on the surface of an existing coating film. The first object is to provide a release agent that can simultaneously increase the coating film thickness and the coating amount of the release agent without dripping from the existing coating film. ..

Furthermore, in the background of the above-mentioned prior art related to high-pressure cleaning, the present inventor has noticed that there are some requests for high-pressure cleaning.

First, from the viewpoint of work quality, there are the following multiple requests.

1. 1. The degree to which the base material of the structure is damaged by the wash water during the physical removal work of the existing coating film using the wash water (the amount by which the base material of the structure is scraped off, etc.) is reduced.

2. The amount of washing water scattered after injection (for example, the sum of the amount of washing water scattered before colliding with a structure and the amount of washing water scattered after colliding with a structure and bouncing off) is reduced.

3. 3. The amount of coating film pieces peeled off from the base material of the structure due to collision with the washing water is reduced.

Further, from the viewpoint of work efficiency, there are a plurality of requests as follows.

1. 1. The amount of wash water scattered before colliding with the structure is reduced, which reduces the amount of wash water consumed without permission and thus the amount of water that needs to be used as wash water. To do.

2. The recoil caused by the cleaning water ejected from the cleaning gun colliding with the surface of the structure is reduced.

3. 3. It is not necessary to re-clean the surface of the structure for re-painting after peeling off the existing coating film with washing water.

In addition, from the viewpoint of environmental protection, there are the following multiple requests.

1. 1. The amount of coating film pieces peeled off from the base material of the structure due to collision with the washing water is reduced.

2. Hazardous substances mixed in the cleaning water after peeling and cleaning as wastewater (or wastewater) (for example, those contained in the existing coating film, those contained in the plating layer of the base material of the structure, and eluted in the cleaning water. To detoxify things that contain things).

3. 3. Reuse the detoxified wastewater as new wash water.

Against these circumstances, another aspect of the present invention is to inject cleaning water at high pressure to peel off the existing coating film from the base material of the structure (for example, a zinc-plated layer as a protective layer of the structure). Provided is a technique for cleaning, which reduces the amount of scattering of cleaning water after injection and / or the amount of coating piece separated from the base material of a structure due to collision with the cleaning water during high-pressure cleaning. This was done as the second task.

Further, against the background of these circumstances, yet another aspect of the present invention is a technique of injecting cleaning water at a high pressure to peel off an existing coating film from the base material of the structure and clean it, toward the structure. The third object is to provide a substance capable of recovering the sprayed washing water as waste water and improving the degree of detoxification thereof.

In order to solve the above-mentioned first problem, according to the first aspect of the present invention, it is a method of wet-peeling an existing coating film from a structure using a release agent.
The method is
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle without using compressed air, whereby the release agent is divided into a plurality of droplets. And the injection process that collides with the surface of the coating film
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.
The release agent is applied to at least one of the viscosity of the release agent, the injection pressure when the release agent is ejected from the nozzle, and the average diameter of the nozzle using the airless spray gun. Provided is a coating film peeling method including a condition setting step of setting the atomizing property of the stripping agent to be poor.

Further, according to the second aspect of the present invention, it is a method of wet-peeling an existing coating film from a structure using a release agent.
The method is
An injection step of injecting the release agent using an airless spray gun to divide it into a plurality of droplets.
The smaller the surface roughness of the existing coating film, the smaller the surface roughness of the coating film to be formed by applying the sprayed release agent onto the surface of the coating film and the release agent on the surface of the coating film. A coating film peeling method including a coating step of coating so as to have a large coating film thickness is provided.

In order to solve the above-mentioned second problem, according to an aspect of the present invention, the existing coating film is removed from the surface of the structure by injecting cleaning water at a high pressure to clean the surface of the structure. A high-pressure cleaning system for removing paint films
A cleaning gun that injects cleaning water from an injection nozzle at high pressure,
A hood attached to the cleaning gun that covers the injection nozzle and extends in the injection direction from the injection nozzle, whereby the amount and / or structure of the cleaning water ejected in the form of mist from the injection nozzle. Including those that reduce the amount of washing water that collides with the surface of an object and bounces off it.
The hood is made of a material that has elasticity at least at its tip,
The cleaning gun has a contact mode for high-pressure cleaning the structure in a state where at least a part of the tip of the hood is in contact with the surface of the structure, and a non-pressure cleaning for the structure without the contact. A high pressure cleaning system for coating film removal is provided that can be used in at least the contact mode of the contact mode.

In order to solve the above-mentioned third problem, according to the first aspect of the present invention, the existing coating film is removed from the surface of the structure by injecting cleaning water at a high pressure to clean the surface of the structure. A high-pressure cleaning system for removing coating films
It includes a wastewater treatment unit that treats the washing water sprayed at high pressure as wastewater containing harmful substances.
The wastewater treatment unit is
A coagulation tank in which a predetermined harmful substance in the wastewater is agglomerated by adding at least one of an adsorbent such as a coagulant, a heavy metal insolubilizer and an activated carbon powder to the wastewater.
By filtering the wastewater in the coagulation tank, the wastewater is separated into a harmful substance as a solid substance and a filtered wastewater from which the harmful substance has been removed.
A high pressure cleaning system for removing a coating film including the above is provided.

Further, according to the second aspect of the present invention, it is a high-pressure cleaning method for removing a coating film that removes an existing coating film from the surface of the structure by injecting cleaning water at a high pressure to clean the surface of the structure. There,
When the washing water jetted at high pressure collides with the structure, the washing water as a liquid component and the coating piece as a solid component, which is a coating piece, are physically collided with the washing water from the surface of the structure. Includes a wastewater treatment step to treat the wastewater produced as a mixture with the stripped and removed material.
The wastewater treatment process is
At least one of an adsorbent such as a flocculant, a heavy metal insolubilizer and an activated carbon powder is added to the wastewater recovered at the high-pressure washing site related to the structure, whereby the wastewater is present in the wastewater. Aggregation process that aggregates harmful substances and
A separation step of separating and recovering the aggregated harmful substances from the wastewater by filtering the wastewater to which the coagulant is added.
A high pressure cleaning method for removing a coating film including the above is provided.

According to the present invention, the following aspects can be obtained. Each aspect is divided into sections, each section is numbered, and the numbers of other sections are cited as necessary. This is to facilitate understanding of some of the technical features that can be adopted by the present invention and their combinations, and the technical features that can be adopted by the present invention and their combinations are limited to the following aspects. Should not be interpreted as. That is, it should be interpreted that it is not hindered from appropriately extracting and adopting the technical features described in the present specification as the technical features of the present invention, which are not described in the following aspects.

Furthermore, describing each term in the form of quoting the numbers of the other sections does not necessarily prevent the technical features described in each section from being separated and independent from the technical features described in the other sections. It does not mean, and it should be interpreted that the technical features described in each section can be made independent as appropriate according to their properties.

(1) A method of wet-peeling an existing coating film from a structure using a release agent.
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle without using compressed air, thereby dividing the release agent into a plurality of droplets. The injection process and
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the release agent is applied on the surface of the coating film in a foamed state.
A coating film peeling method including a peeling step of physically peeling an existing coating film softened by the release agent from the structure after a lapse of a required time from the completion of the coating.

(2) The coating film peeling method according to item (1), wherein the release agent has a high viscosity.

(3) The coating film peeling method according to item (1) or (2), wherein the stripping agent is an aqueous stripping agent emulsion in which a main component and water are emulsified using a surfactant.

(4) The coating film peeling method according to item (1) or (2), wherein the release agent is a solvent-based release agent.

(5) In the coating step, the release agent is applied to the surface of the coating film so that the release agent in the foamed state has a plurality of bubbles having an average diameter in the range of about 0.1 mm to about 0.5 mm. The coating film peeling method according to any one of (1) to (4), which is applied above.

(6) In the coating step, the release agent is applied to the surface of the coating film so that the average coating film thickness of the coating film formed by applying the release agent onto the surface of the coating film is about 1 mm. The coating film peeling method according to any one of (1) to (5), which is applied above.

(7) In the coating step, the coating film is formed by applying the release agent onto the surface of the coating film so that the average coating film thickness is in the range of about 2 mm to about 5 mm. The coating film peeling method according to any one of (1) to (5), wherein the release agent is applied onto the surface of the coating film.

(8) In the coating step, the coating film formed by the release agent being applied onto the surface of the coating film has a larger coating film thickness as the surface roughness of the existing coating film is smaller. The coating film peeling method according to any one of (1) to (7), wherein the release agent is applied onto the surface of the coating film.

(9) In the injection step, the release agent is pressurized with an injection pressure having a height that changes according to the viscosity of the release agent and the discharge amount of the release agent from the nozzle, and the release agent is injected from the nozzle. The coating film peeling method according to any one of 1) to (8).

(10) The release agent is volatile and has
The coating film peeling method further
After the application of the release agent is completed, the surface of the coating film is wrapped with a protective sheet that is impermeable to the release agent, whereby the vaporized gas generated from the release agent is released from the surface of the coating film to the atmosphere. Including a wrapping step to prevent it from being
The coating film peeling method according to any one of (1) to (9), wherein the peeling step includes a step of peeling the protective sheet from the existing coating film after the required time has elapsed.

(11) The injection step does not include a step of bringing the release agent into contact with the flow of compressed air and atomizing the release agent by the principle of spraying, and further, the release agent is said before being injected from the nozzle. The coating film peeling method according to any one of (1) to (10), which does not include a step of foaming a release agent.

(21) A method of wet-peeling an existing coating film from a structure using a release agent.
The release agent has a high viscosity of more than 0.1 Pa · s and has a high viscosity.
The method is
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle without using compressed air, whereby the release agent is divided into a plurality of droplets. And the injection process that collides with the surface of the coating film
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. A coating film peeling method comprising a method in which each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.

(22) The coating film peeling method according to item (21), wherein the peeling agent has a viscosity not exceeding 16 Pa · s (20 ° C.).

(23) The coating film peeling method according to (21) or (22), wherein the release agent is an aqueous release agent emulsion in which a main component and water are emulsified using a surfactant.

(24) The coating film peeling method according to item (21) or (22), wherein the stripping agent is a solvent-based stripping agent.

(25) The coating film peeling method according to any one of (21) to (24), wherein the injection step is to inject the release agent from the nozzle at an ^{injection pressure not exceeding 80 kg / cm 2.}

(26) In the coating step, the peeling is performed so that the average coating film thickness of the coating film formed by the release agent being applied onto the surface of the coating film without recoating is not less than about 1 mm. The coating film peeling method according to any one of (21) to (25), wherein the agent is applied onto the surface of the coating film.

(27) In the coating step, the average coating film thickness of the coating film formed by applying the release agent onto the coating film surface without recoating is within the range of about 2 mm to about 5 mm. The coating film peeling method according to any one of (21) to (25), wherein the release agent is applied onto the surface of the coating film.

(28) The coating film peeling according to any one of (21) to (27), wherein in the coating step, the release agent is applied onto the coating film surface so as to have a coating amount of ^{1.0 kg / m 2.} Method.

(29) In the injection step, the release agent is pressurized with an injection pressure having a height that changes according to the viscosity of the release agent and the discharge amount of the release agent from the nozzle, and the release agent is injected from the nozzle (29). 21) The method for peeling a coating film according to any one of items (28) to (28).

(30) The release agent is volatile and has
The coating film peeling method further
After the application of the release agent is completed, the surface of the coating film is wrapped with a protective sheet that is impermeable to the release agent, whereby the vaporized gas generated from the release agent is released from the surface of the coating film to the atmosphere. The wrapping process to prevent it from being done,
Any of (21) to (29), which includes a peeling step of peeling the protective sheet from the existing coating film after a lapse of a predetermined time, and further peeling the existing coating film softened by the release agent from the structure. The coating film peeling method described in Crab.

(31) The injection step does not include a step of bringing the release agent into contact with the flow of compressed air and atomizing the release agent by the principle of spraying, and further, before injecting the release agent from the nozzle. The coating film peeling method according to any one of (21) to (30), which does not include a step of foaming the release agent.

(51) A method of wet-peeling an existing coating film from a structure using a release agent.
The method is
By using an airless spray gun having a nozzle, the release agent itself is pressurized and the release agent is ejected from the nozzle without using compressed air, whereby the release agent is divided into a plurality of droplets. And the injection process that collides with the surface of the coating film
In a coating step of applying the sprayed release agent onto the surface of the coating film, the plurality of droplets of the release agent collide with the surface of the coating film during the application, whereby the plurality of liquids are applied. Each of the droplets entrains air in the atmosphere and foams, whereby the plurality of droplets are adhered and fixed on the surface of the coating film as a plurality of air bubbles.
At least one of the viscosity of the release agent, the injection pressure when the release agent is ejected from the nozzle, and the average diameter of the nozzle is sprayed with the release agent using the airless spray gun. A coating method that is set so that the atomizing property of the release agent is deteriorated.

(52) The coating according to item (51), wherein at least one of the viscosity, the injection pressure, and the average diameter is set so that the average particle size of each of the plurality of droplets is larger than 50 μm. Film peeling method.

(53) The coating film peeling method according to item (51) or (52), wherein the viscosity is set to a value higher than 0.1 Pa · s (20 ° C.).

(54) The coating film peeling method according to any one of (51) to (53), wherein the injection pressure is ^{set to a height not exceeding 80 kg / cm 2.}

(55) The coating film peeling method according to any one of (51) to (54), wherein the equivalent diameter is set to a value of 0.4 mm or more.

(56) The coating film peeling method according to any one of (51) to (55), wherein the viscosity is set to a value not exceeding 16 Pa · s (20 ° C.).

(57) In the coating step, the peeling is performed so that the average coating film thickness of the coating film formed by the release agent being applied onto the surface of the coating film without recoating is not less than about 1 mm. The coating film peeling method according to any one of (51) to (56), wherein the agent is applied onto the surface of the coating film.

(58) In the coating step, the average coating film thickness of the coating film formed by applying the release agent onto the coating film surface without recoating is within the range of about 2 mm to about 5 mm. The coating film peeling method according to any one of (51) to (57), wherein the release agent is applied onto the surface of the coating film.

(59) The coating film peeling according to any one of (51) to (58), wherein in the coating step, the release agent is applied onto the surface of the coating film so as to have a coating amount of ^{1.0 kg / m 2.} Method.

(60) In the injection step, the release agent is pressurized with an injection pressure having a height that changes according to the viscosity of the release agent and the discharge amount of the release agent from the nozzle, and the release agent is injected from the nozzle (60). 51) The method for peeling a coating film according to any one of items (59) to (59).

(61) The release agent is volatile and has
The coating film peeling method further
After the application of the release agent is completed, the surface of the coating film is wrapped with a protective sheet that is impermeable to the release agent, whereby the vaporized gas generated from the release agent is released from the surface of the coating film to the atmosphere. The wrapping process to prevent it from being done,
Any of (51) to (60), which includes a peeling step of peeling the protective sheet from the existing coating film after a lapse of a predetermined time, and further peeling the existing coating film softened by the release agent from the structure. The coating film peeling method described in Crab.

(62) The injection step does not include a step of bringing the release agent into contact with the flow of compressed air and atomizing the release agent by the principle of spraying, and further, before injecting the release agent from the nozzle. The method for removing a coating film according to any one of (51) to (61), which does not include a step of foaming a release agent.

(63) A method of wet-peeling an existing coating film from a structure using a release agent.
The method is
An injection step of injecting the release agent using an airless spray gun to divide it into a plurality of droplets.
The smaller the surface roughness of the existing coating film, the smaller the surface roughness of the coating film to be formed by applying the sprayed release agent onto the surface of the coating film and the release agent on the surface of the coating film. A coating film peeling method including a coating step of applying so as to have a large coating film thickness.

(71) A high-pressure cleaning system for removing a coating film that removes an existing coating film from the surface of a structure by injecting cleaning water at a high pressure to clean the surface of the structure.
A cleaning gun that injects cleaning water from an injection nozzle at high pressure,
A hood attached to the cleaning gun that covers the injection nozzle and extends in the injection direction from the injection nozzle, whereby the amount and / or structure of the cleaning water ejected in the form of mist from the injection nozzle. Including those that reduce the amount of washing water that collides with the surface of an object and bounces off it.
The hood is made of a material that has elasticity at least at its tip,
The cleaning gun has a contact mode for high-pressure cleaning the structure in a state where at least a part of the tip of the hood is in contact with the surface of the structure, and a non-pressure cleaning for the structure without the contact. A high pressure cleaning system for coating film removal that can be used in at least the contact mode of the contact mode.

(72) The hood generally has a hollow thin-walled conical shape as a whole, and gradually expands as it advances from the injection nozzle in the injection direction, and has a circular shape, an elliptical shape, or an oval shape as a cross-sectional shape. The high-pressure cleaning system for removing a coating film according to item (71), which forms a non-circular shape so as to have corners at at least one position in the circumferential direction of the hood.

(73) The high-pressure cleaning system for removing a coating film according to item (71) or (72), wherein the material has at least a partial light transmission at at least a tip portion.

(74) The high-pressure cleaning system for removing a coating film according to any one of (71) to (73), wherein the material contains silicone at least at the tip.

(75) The injection nozzle is a flat-blowing nozzle, which allows the cleaning gun to inject cleaning water in a fan-shaped spray pattern, whereby the injected cleaning water is elongated. The high-pressure cleaning system for removing a coating film according to any one of (71) to (74), which collides with the surface of the structure in a momentary cleaning region.

(76) The cleaning gun injects the cleaning water in a state where the injection distance, which is the distance from the injection nozzle to the target reaching point on the structure, is about 50 to about 200 mm (71) to (75). ) The high-pressure cleaning system for removing the coating film according to any one of the items.

(77) The high pressure for removing a coating film according to any one of (71) to (76), wherein the cleaning gun is configured to inject the cleaning water at an injection pressure of about 80 to about 250 kgf / cm ^2. Cleaning system.

(78) The high-pressure cleaning for removing a coating film according to any one of (71) to (77), wherein the cleaning gun is configured to inject the cleaning water at an injection rate of about 8 to about 20 L / min. system.

(79) The cleaning gun is
A trigger as the main operating tool operated by one hand of the operator,
A flow rate adjusting valve that turns the cleaning gun on and off and adjusts the flow rate according to the amount of operation of the trigger.
An injection pressure adjuster as an auxiliary operating tool operated by the hand on the opposite side of the operator,
Item 2. The high pressure for removing a coating film according to any one of (71) to (78), which includes an injection pressure adjusting valve that adjusts the injection pressure of the washing water from the cleaning gun according to the operation amount of the injection pressure adjusting tool. Cleaning system.

(80) Further, a wastewater treatment unit that collects and treats the washing water injected from the injection nozzle as wastewater is included.
The wastewater treatment unit comprises a scaffolding installed on the structure for workers and a double sheet installed below its flooring.
The double sheet includes an upper filtration sheet and a lower water collecting sheet, which are arranged so as to overlap each other in a plan view.
The filtration sheet is configured to receive the wastewater and filter the wastewater to remove coating film pieces as solid matter from the wastewater.
The water collecting sheet is configured to receive the filtered wastewater from the filtered sheet and guide the filtered wastewater to the wastewater outlet by utilizing its own weight. High-pressure cleaning system for removing coating film described in Crab.

(81) The wastewater treatment unit further
Together and stores the recovered waste water after filtration discharged from the waste water outlet, coagulant to the waste water containing hazardous substances, at least one of the adsorbent such as heavy metal insoluble agent and active carbon powder is added As a result, a coagulation tank in which a predetermined harmful substance in the wastewater is agglomerated, and
By filtering the wastewater in the coagulation tank, the wastewater is separated into harmful substances as solids and wastewater after filtration from which the harmful substances have been removed, and a filtration unit.
Item (80) includes an optional ion exchange fiber layer or ion exchange resin layer that captures and recovers heavy metal ions in the wastewater when the filtered wastewater passes through the layer. Described high pressure cleaning system for coating film removal.

(82) The wastewater treatment unit further
Reuse means for reusing detoxified wastewater that has passed through the filtration section and discharged from it as new washing water.
The high-pressure cleaning system for removing a coating film according to item (81), which comprises a dehydration means for dehydrating wet flocs that do not pass through the filtration section but remain there and contain the harmful substances.

(83) A high-pressure cleaning method for removing a coating film, which removes an existing coating film from the surface of the structure by injecting cleaning water at a high pressure to clean the surface of the structure.
The method is a cleaning gun that injects cleaning water from an injection nozzle at a high pressure, covers the injection nozzle, extends from the injection nozzle in the injection direction, and thereby injects cleaning water in the form of mist from the injection nozzle. And / or with a hood-equipped hood that reduces the amount of wash water that collides with and / or bounces off the surface of the structure.
The method is
The first step of using the cleaning gun in a contact mode for high-pressure cleaning the structure in a state where at least a part of the tip of the hood is in contact with the surface of the structure.
A second step in which the cleaning gun is used in a non-contact mode in which the structure is washed under high pressure without contacting the surface of the structure in the hood, which is optionally performed.
Regardless of which of the first step and the second step is carried out, in parallel with the step to be carried out, the washing gun sprayed with the washing gun collides with the surface of the structure in an elongated momentary manner. A high-pressure cleaning method for removing a coating film, which comprises a third step of moving and sweeping in a direction intersecting the cleaning area.

(91) A method of removing an existing coating film from the surface of a painted structure by collision with high-pressure washing water.
Mechanical removal of removing the existing coating film from the surface of the structure by injecting cleaning water from the injection port of the cleaning gun under pressure using a hand-held cleaning gun, and the structure thereof. A high-pressure washing process in which the surface of the surface is washed with washing water, and
When the jetted washing water collides with the structure, the washing water as a liquid component and the coating piece as a solid component, which is a coating piece, physically collide with the washing water from the surface of the structure. Includes a wastewater treatment step that treats the wastewater produced as a mixture with the stripped and removed material.
In the high-pressure washing step, the amount of the washing water ejected from the washing gun that scatters laterally from the planned flight path when the washing water flies in the air exceeds a predetermined allowable value. Not like
(A) The injection pressure, which is the pressure of the cleaning water at the injection port of the cleaning gun,
(B) The injection angle, which is the apex angle of the fan-shaped spray pattern that spreads toward the end as the shape of the flight path when the cleaning water is injected from the injection port of the cleaning gun and then flies in the air.
(C) Distribution of pressure in each cross section of the fan-shaped spray pattern of the washing water sprayed from the injection port of the washing gun.
(D) Two conditions are set for at least two of the four control variables including the injection amount, which is the amount of the cleaning water injected from the injection port of the cleaning gun per unit time, and the set conditions. The cleaning water is sprayed from the cleaning gun under the above conditions.
The wastewater treatment step is
A wastewater recovery step of collecting the wastewater at a high-pressure washing site related to the structure and storing it in a container installed at a predetermined position.
A coagulation step in which a coagulant is added to the wastewater contained in the container to coagulate harmful substances existing in the wastewater.
A separation step of separating and recovering the aggregated harmful substances from the wastewater by filtering the wastewater to which the coagulant has been added.
At the work site related to the structure, the component of the wastewater after filtration is analyzed by using an analysis kit, and the component of the wastewater is a predetermined wastewater standard, and the standard regarding the transparency of the wastewater after filtration is set. An analysis process that determines whether or not to satisfy what you have,
When it is determined that the components of the wastewater satisfy the wastewater standard, the wastewater / reuse step of draining the wastewater or reusing it for the next high-pressure washing is performed.
When it is determined that the components of the wastewater do not meet the wastewater standard, a high-pressure washing type coating film removing method including the agglutination step, the agglutination recovery step, and a repeating step of repeating the analysis step for the wastewater. ..

(92) The structure is made of metal, the surface of the structure is coated with a zinc-plated layer, and the zinc-plated layer is coated with the existing coating film.
Item (91), wherein the high-pressure washing step is carried out under injection conditions in which damage to the galvanized layer due to washing water is substantially minimized, whereby the rust preventive ability of the structure is substantially maintained. The method for removing a high-pressure cleaning type coating film according to the above method.

(93) The injection conditions are
The injection pressure condition that the injection pressure is in the range of about 80-about 250 kgf / cm ^{2 and}
The injection angle condition that the injection angle is in the range of about 10 to about 15 degrees, and
Pressure distribution conditions in which the pressure distribution of the sprayed wash water in each cross section of the fan-shaped spray pattern is substantially uniform, and
The high-pressure cleaning type coating film removing method according to item (91) or (92), which cumulatively includes an injection amount condition that the injection amount is in the range of about 8 to about 20 L / min.

(94) The high-pressure washing step is
Prior to applying the release agent onto the existing coating film, the washing water is sprayed toward the existing coating film, whereby the release agent is to be applied on the surface of the existing coating film. A pre-cleaning step of cleaning the existing coating film and removing the portion of the existing coating film that has risen from the surface of the structure before applying the release agent.
After the existing coating film is swollen and softened on the structure by the release agent applied on the existing coating film, the washing water is sprayed toward the existing coating film, whereby the existing coating film is formed. The high-pressure cleaning type coating film removing method according to any one of (91) to (93), which includes a production cleaning step of peeling and removing from the structure.

(95) The first injection pressure is less than about 50%, less than about 60%, less than about 70%, less than about 80%, or less than about 90% of the second injection pressure. High-pressure cleaning type coating film removal method.

(96) The high-pressure washing according to any one of (91) to (95), wherein the washing gun has a recoil reducing means for reducing the recoil caused by the washing water jetted from the washing gun colliding with the structure. Mold coating removal method.

(97) The reaction reducing means injects compressed air in the cleaning gun in the direction opposite to the injection direction of the cleaning water when the cleaning water is injected and in coaxial with the injection direction. The high-pressure cleaning type coating film removing method according to (96), wherein the reaction is at least partially canceled by the second reaction generated by the compressed air injected from the same cleaning gun colliding with the surrounding static air. ..

(98) In the wastewater recovery step, a water collecting sheet that is variably installed so as to surround a work site that moves sequentially in the structure and a drain hose that extends from the water collecting sheet are used. The high-pressure washing type coating film removing method according to any one of (91) to (97), wherein the wastewater is collected at a work site and the collected wastewater is sent to the container.

(99) The harmful substance contains heavy metals (lead, etc.), chromium and PCB.
The flocculant is
The condition that the harmful substances are selectively aggregated and
The condition that the content concentration of the harmful substance in the wastewater after filtration is less than a predetermined reference value,
The high-pressure washing type coating film removing method according to any one of (91) to (98), which is selected so as to cumulatively satisfy the condition that the transparency of the wastewater after filtration exceeds a predetermined reference value.

(101) A high-pressure cleaning system for removing a coating film that removes an existing coating film from the surface of a structure by injecting cleaning water at a high pressure to clean the surface of the structure.
It includes a wastewater treatment unit that treats the washing water sprayed at high pressure as wastewater containing harmful substances.
The wastewater treatment unit is
A coagulation tank in which a predetermined harmful substance in the wastewater is agglomerated by adding at least one of an adsorbent such as a coagulant, a heavy metal insolubilizer and an activated carbon powder to the wastewater.
By filtering the wastewater in the coagulation tank, the wastewater is separated into a harmful substance as a solid substance and a filtered wastewater from which the harmful substance has been removed.
High pressure cleaning system for coating film removal including.

(102) The wastewater treatment unit is further an ion exchange fiber layer or an ion exchange resin layer, which captures and recovers heavy metal ions in the wastewater when the filtered wastewater passes through the layer. The high-pressure cleaning system for removing a coating film according to item (101).

(103) The wastewater treatment unit further includes
Reuse means for reusing detoxified wastewater that has passed through the filtration section and discharged from it as new washing water.
As a weight reduction means for dehydrating wet flocs that do not pass through the filtration section and remain there and contain the harmful substances, thereby reducing the amount of harmful substance waste to be discarded.
The high pressure cleaning system for removing a coating film according to (101) or (102).

(104) A high-pressure cleaning method for removing a coating film, which removes an existing coating film from the surface of the structure by injecting cleaning water at a high pressure to clean the surface of the structure.
When the washing water jetted at high pressure collides with the structure, the washing water as a liquid component and the coating piece as a solid component, which is a coating piece, are physically collided with the washing water from the surface of the structure. Includes a wastewater treatment step to treat the wastewater produced as a mixture with the stripped and removed material.
The wastewater treatment process is
At least one of an adsorbent such as a flocculant, a heavy metal insolubilizer and an activated carbon powder is added to the wastewater recovered at the high-pressure washing site related to the structure, whereby the wastewater is present in the wastewater. Aggregation process that aggregates harmful substances and
A separation step of separating and recovering the aggregated harmful substances from the wastewater by filtering the wastewater to which the coagulant is added.
High-pressure cleaning method for removing coating film including.

(105) The wastewater treatment step further includes
At the work site related to the structure, the component of the wastewater after filtration is analyzed by using an analysis kit, and the component of the wastewater is a predetermined wastewater standard, and the standard regarding the transparency of the wastewater after filtration is set. An analysis process that determines whether or not to satisfy what you have,
When it is determined that the components of the wastewater satisfy the wastewater standard, the wastewater / reuse step of draining the wastewater or reusing it for the next high-pressure washing is performed.
When it is determined that the components of the wastewater do not meet the wastewater standard, the wastewater is subjected to a repetitive step of repeating the aggregation step, the separation step and the analysis step.
The high pressure cleaning method for removing a coating film according to item (104).

FIG. 1 is a system diagram conceptually representing an exemplary airless coating machine used to carry out a coating film peeling method according to an exemplary first embodiment of the present invention. FIG. 2 is a table showing the composition and operating temperature of each of a plurality of types of release agents, that is, removers, which are selectively used in the airless coating machine shown in FIG. FIG. 3 is a process diagram showing an exemplary preparatory step in the coating film peeling method. FIG. 4 is a process diagram showing an exemplary construction process in the coating film peeling method. FIG. 5 is a diagram conceptually showing the temporal transition of the properties of the remover injected from the nozzle of the airless spray gun shown in FIG. FIG. 6 is a diagram showing the test results of the coatability of a remover applied on an existing coating film according to an embodiment of the present invention in comparison with a comparative example. FIG. 7A shows the viscosity of the release agent before being sprayed from the airless spray gun when the liquid release agent is airlessly applied, and the particle size of each of the plurality of droplets in which the release agent is divided by the spray. It is a graph conceptually showing the general relationship established between (for example, average diameter) and the atomizing property of a release agent by an airless spray gun, and FIG. 3B is an airless graph in the same spray environment. 6 is a graph conceptually showing a general relationship established between the injection pressure of a release agent from a spray gun and the particle size of each of the droplets. FIG. 8 shows the thickness of the film to which the release agent should be applied on the surface of the existing coating film according to the surface roughness of the existing coating film when the coating film peeling method according to the first embodiment is carried out. It is a graph which conceptually represents an example of the process which determines the average coating film thickness. FIG. 9 is a process diagram showing an example of a coating film peeling method according to an exemplary second embodiment of the present invention. FIG. 10 is a partial cross-sectional side view showing a cleaning gun of the coating film removing high pressure cleaning system used to perform the high pressure cleaning in FIG. FIG. 11A is a front view showing the hood shown in FIG. 10 taken out, and FIG. 11B is a cross-sectional view showing a base end portion of the hood. FIG. 12 (a) is a perspective view showing a spray pattern of washing water sprayed from the washing gun shown in FIG. 10, and FIG. 12 (b) is a front view showing an enlarged view of an injection nozzle of the washing gun. It is a figure. FIG. 13A is a perspective view for explaining how the hood shown in FIG. 10 is geometrically fitted to the inside corner of the angle member in the structure to be worked, and FIG. 13B is a perspective view. It is a side view for chronologically explaining how the hood overcomes the exposed portion of the bolt fastened to the angle member by elastic deformation during the sweeping of the cleaning gun shown in FIG. c) is a front view for explaining how the hood elastically deforms when it gets over the exposed portion of the bolt. FIG. 14A is a graph for conceptually explaining the relationship between the amount of injected water and the impact pressure as a plurality of cleaning force characteristics of the cleaning gun shown in FIG. 10, and FIG. 14B is an injection angle. It is a graph for conceptually explaining the relationship between and impact pressure. FIG. 15A is a graph for conceptually explaining the relationship between the injection pressure and the impact pressure as a plurality of different cleaning force characteristics of the cleaning gun shown in FIG. 10, and FIG. 15B is a graph for explaining the relationship between the injection pressure and the impact pressure. It is a graph for conceptually explaining the relationship between the injection distance and the impact pressure. FIG. 16 is a perspective view for conceptually explaining a plurality of places and a plurality of directions in which the cleaning water is scattered when the cleaning gun shown in FIG. 10 injects the cleaning water and collides with the cleaning surface. FIG. 17A is a perspective view showing an example of a double sheet as a part of the wastewater treatment unit used for carrying out the wastewater treatment in FIG. 9, and FIG. 17B is a perspective view thereof. It is a side view which shows the water collecting sheet of the double sheet. FIG. 18 is a perspective view showing an example of the remaining portion of the wastewater treatment unit shown in FIG. FIG. 19 is a process diagram showing an example of wastewater treatment shown in FIG. FIG. 20 is a process diagram showing another example of the coating film peeling method shown in FIG.

[First Embodiment]

Hereinafter, an exemplary first embodiment of the present invention will be described in detail with reference to the drawings.

An exemplary embodiment of the present invention relates to a wet peeling method for stripping an existing coating film from a structure (or a structure) using a stripping agent (hereinafter, also referred to as “remover”). Specifically, the wet peeling method is a foaming airless coating peeling method in which a peeling agent is applied onto an existing coating film by foaming airless (airless injection, airless spraying) to peel off.

An example of the foaming airless coating peeling method is a method of applying a foaming airless coating on an existing coating film and peeling.

Here, "high viscosity" means, for example, a viscosity higher than the viscosity limit (for example, 0.1 Pa · s (20 ° C.)) at which general coating is possible when expressed in terms of paint viscosity. For example, "high viscosity" means a viscosity corresponding to gel coat paint (3 Pa · s (20 ° C.)) or higher, or a viscosity corresponding to mayonnaise (23 ° C.) (8 Pa · s (20 ° C.)). )) Or higher viscosity may be meant.

Another example of the foaming airless coating peeling method is a method in which a highly viscous and emulsified stripping agent is coated on an existing coating film by foaming airless coating and peeled. An example of a highly viscous and emulsified release agent is the first remover shown in FIG. 2, as will be described later.

The above-mentioned foaming airless coating peeling method (hereinafter, referred to as “main peeling method”) includes a foaming airless coating step S201 as a chemical peeling step and a physical method, as will be described in detail later with reference to FIG. The peeling step S203 as a specific (mechanical) peeling step is provided as a plurality of steps to be carried out in that order.

FIG. 1 conceptually shows an exemplary airless coating machine 10 used for carrying out the foam-type airless coating step S201 described above in a system diagram.

The airless coating machine 10 includes a tank 30 for storing a release agent 20 applied on the existing coating film 14 in order to wetly peel the existing coating film 14 from the structure 12, and an airless type pump 40 (pumping machine). And an airless spray gun (hereinafter, simply referred to as "spray gun") 50, and an air compressor 60 as a drive source of the pressure feed pump 40. The type of the spray gun 50 may be a hand-held hand gun or an automatic gun.

Specifically, the air compressor 60 applies a high pressure to the pressurizing chamber 76 located behind the plunger or piston, which will be described later, thereby causing a discharge chamber (high viscosity to be discharged) located in front of the plunger or piston. 20 is used to pressurize the room 80 from which the release agent 20 is fed from the tank 30.

The airless spray method using the spray gun 50 will be described in detail later with reference to FIG. 5, but briefly explained, a high pressure is applied to the release agent 20 to form a liquid film, and the liquid film is formed into the atmosphere (static air). This is a method of atomizing the release agent 20 into droplets.

The tank 30 is connected to the supply port 72 of the pump 40 via a hose 70. The supply port 72 is fluidly connected to the discharge port 80. The air compressor 60 is connected to the pressurizing chamber 76 of the pressure feed pump 40 via the air hose 74. The spray gun 50 is connected to the discharge chamber 80 of the pressure feed pump 40 via a high pressure hose 78. In the airless coating machine 10, the hose 70 constitutes a supply line, the air hose 74 constitutes a compressed air line, and the high pressure hose 78 constitutes a pumping line.

The spray gun 50 pressurizes the release agent 20 itself by the plunger or the piston and injects the release agent 20 from the nozzle without bringing the compressed air into direct contact with the release agent 20, thereby causing the release agent 20 to be plurality. It is configured to be divided into droplets of.

<Spray factor setting>

In the present embodiment, the spray factor, that is, the viscosity of the release agent 20, the injection pressure when the release agent 20 is ejected from the nozzle (“atomization pressure”), and the average diameter of the nozzle. At least one is set so that the atomizing property of the release agent 20 when the release agent 20 is sprayed using the airless spray gun 50 is deteriorated.

The reason for setting the spray factor so that the atomizing property of the release agent 20 is deteriorated will be described in detail later, but will be briefly described as follows.

That is, when the atomizing property of the release agent 20 is deteriorated, the average particle size of each of the plurality of droplets in which the release agent 20 is divided by spraying is good in atomizing property. Become bigger. On the other hand, the larger the average particle size, the larger the momentum (= mv) of each droplet when each droplet flies in the static air, and the higher the ability to penetrate the static air, and as a result, each liquid. The flight speed of the droplets is faster than when each droplet is small. As a result, the impact energy (collision energy) when each droplet collides with the surface of the existing coating film 14 becomes larger than when the atomization property is good.

FIG. 7A shows the viscosity of the release agent 20 before being sprayed from the airless spray gun 50 when the liquid release agent 20 is airlessly applied, and the plurality of droplets in which the release agent 20 is divided by the spray. The general relationship established between each particle size (for example, average diameter) and the atomization property of the release agent 20 by the airless spray gun 50 is conceptually represented by a graph.

Specifically, the higher the viscosity, the larger the particle size, which results in poor atomization. In one example, it is defined that the atomizing property is good in the region where the particle size is 50 μm or less, whereas the atomizing property is poor in the region where the particle size is larger than 50 μm.

Further, in FIG. 3B, a general relationship established between the injection pressure of the release agent 20 from the airless spray gun 50 and the particle size of each of the droplets in the same spray environment is conceptually defined in a graph. It is represented as. Specifically, the lower the injection pressure, the larger the particle size, which results in poor atomization. Similar to the above, in one example, the atomizing property is good in the region where the particle size is 50 μm or less, whereas the atomizing property is poor in the region where the particle size is larger than 50 μm. Defined.

Then, in the present embodiment, the viscosity of the release agent 20 is set to a value higher than 0.1 Pa · s (20 ° C.) in order to deteriorate the atomization property. However, the higher the viscosity, the more desirable it is, and there is an upper limit. The upper limit is, for example, 16 Pa · s (20 ° C.). The upper limit is necessary because if the viscosity is too high, the release agent 20 may not atomize at all.

Further, in the present embodiment, the injection pressure is set to a height not exceeding ^{80 kg / cm 2 in order to deteriorate the atomization property.}

Further, in the present embodiment, the equivalent diameter of the nozzle (hereinafter, also referred to as “nozzle diameter”) is set to a value of 0.4 mm or more in order to deteriorate the atomization property. This is because the smaller the equivalent diameter, the easier it is for the release agent 20 to atomize, whereas the larger the nozzle diameter, the more the release agent 20 is maintained in a liquid state and less likely to be atomized.

Furthermore, the spraying conditions that deteriorate the atomization property will be extended.

In the spray gun 50, the pressure acting on the release agent 20 (for example, the injection pressure described later) is usually ^{about 80-200 kg / cm 2} , but in the present embodiment, as described later, for example, 30 The pressure is lower than the normal value, such as -40 kg / cm ^2.

The spray gun 50 may adopt either a diaphragm type, a plunger pump type using a plunger, or a piston pump type using a piston as a method for discharging the release agent 20 as a material from the nozzle of the spray gun 50. However, when the release agent 20 has a high viscosity, it is desirable to adopt a plunger pump type or a piston pump type.

Further, since the spray gun 50 has a low injection pressure as described above, a pressure feeding type (release agent 20 is added) as a method of feeding the release agent 20 as a material into the discharge chamber inside the spray gun 50. Rather than pressing and pushing out), a gravity type (using free fall to inject the release agent 20) or a blow-up type (using the air flow to blow up and inject the release agent 20) may be adopted. However, a pumping type may be adopted.

Regardless of which method is adopted, the spray gun 50 is configured to have a main body 90 and a nozzle tip 92 that is detachably attached to the main body 90. The main body 90 is configured to include a grip 94 gripped by the operator and a trigger 96 operated by the operator.

The nozzle tip 92 has a nozzle into which the release agent 20 is sprayed. The cross-sectional shape of the nozzle can be, for example, circular, elliptical, or slit. In the present embodiment, the cross-sectional shape of the nozzle is elliptical, and the equivalent diameter of the nozzle is 0.59 mm (within the range of 0.4 to 0.8 mm). Here, the "equivalent diameter" means the outer diameter of the circular region when the opening region of the nozzle opening is replaced with a circular region having the same area.

The discharge amount of the release agent 20 from the spray gun 50 (also referred to as the injection amount, defined as, for example, the weight of the release agent 20 discharged from the nozzle per fixed time) and the spraying pattern depend on the shape of the nozzle.

In the present embodiment, when the target spraying pattern of the release agent 20 from the elliptical nozzle of the spray gun 50 is viewed from the side (the direction perpendicular to the long axis of the cross-sectional shape of the elliptical nozzle), for example, It is an isosceles triangle (fan shape) that widens as it progresses in the injection direction. In that triangle, for example, the height (spray distance) is about 25 cm and the base length (pattern width) is about 15-20 cm. be.

Further, in the present embodiment, when the elliptical nozzle is adopted, when the injection pressure is 60 kg / cm ² , the injection amount is 1490 mL / min, and the injection pressure is 30-40 kg / cm ² . When the injection amount is 750-1000 mL / min.

Features of the spray gun 50

The spray gun 50 applies pressure to the release agent 20 itself by forcibly injecting the release agent 20 from the nozzle without depending on air blowing.

To explain the principle that the release agent 20 is atomized by the airless spray method using the spray gun 50, first, as shown in FIG. 5, the release agent 20 is sprayed from the nozzle as a liquid film at high pressure. The tip of the liquid film collides with the surrounding static air, which gradually reduces the velocity of the tip of the liquid film. On the other hand, since the pressure for injecting the release agent 20 is constant, the liquid film becomes wavy. As the wavy liquid film travels in the static air, it receives resistance from the static air, and the wavy liquid film splits into a plurality of parts arranged in the traveling direction of the liquid film.

After that, each split liquid film extends in a direction intersecting with the traveling direction, and is formed into a concavo-convex string so as to repeat concave and convex portions in the extending direction.

The uneven string-shaped portion is then divided into a plurality of droplets arranged in the extending direction of the concave-convex string portion, whereby the release agent 20 is formed into droplets.

By the way, since the spray gun 50 directly sprays the high-pressure release agent 20, the amount of the release agent 20 scattered is smaller than that of the air spray gun, and the coating efficiency (for example, with respect to the total weight We of the sprayed release agent 20). Of the sprayed release agent 20, the portion coated on the existing coating film 14 (excluding the scattered portion) is defined as the ratio of the amount W).

That is, since the spray gun 50 atomizes and applies the release agent 20 without using air, the amount of the release agent 20 atomized and scattered in the air is small, which causes health hazards to the environment and workers. The amount is small, and the coating efficiency of the release agent 20 (for example, coating efficiency) is high.

Further, since the release agent 20 can be applied while supplying the release agent 20 to the spray gun 50, it is suitable for streamlining the release work.

Since the spray gun 50 can apply the release agent 20 on the existing coating film 14 at a higher pressure than the air spray gun, a thick film of the release agent 20 can be formed on the existing coating film 14.

However, since the spray gun 50 sprays a larger amount of the release agent 20 than the air spray gun, the release agent 20 applied on the existing coating film 14 is likely to drip unless additional measures are taken. ..

Therefore, in the present embodiment, some measures have been added in order to improve the adhesiveness (adhesiveness, adhesiveness, etc.) of the release agent 20 on the existing coating film 14.

(1) Foaming of the release agent 20 by optimizing the injection factor

In comparison with the air spray gun, according to the experiment of the present invention, the higher the injection pressure of the release agent 20 from the spray gun 50 (for example, the higher the pressure acting on the spray gun 50 from the air compressor 60). It has been found that the spraying speed of the release agent 20 from the spray gun 50 is increased and the cross-sectional diameter (spraying diameter) of the spraying pattern (for example, conical shape) is reduced.

Further, as described above, by optimizing the injection factor, that is, by combining the high viscosity of the release agent 20, the low injection pressure, and the large nozzle diameter, the particle size of each droplet of the release agent 20 can be increased. The diameter is increased, which increases the flight speed of each droplet as it flies in static air.

As described above, in the present embodiment, by optimizing such an injection factor, each droplet is speeded up in combination with the adoption of the airless spray gun 50 instead of the air spray gun.

Due to the high speed of each droplet, the impact energy when each of the above-mentioned droplets collides with the existing coating film 14 increases, and each droplet becomes finer due to the collision, and the total number of droplets increases, and as a result, The surface area of the droplets as a whole, that is, the contact area with static air, increases. As a result, the droplets entrain more static air and foam. As a result, each droplet becomes finer, and as a whole, a larger number of bubbles (air bubbles) are formed in the release agent 20.

On the other hand, in the release agent 20 having the same coating film thickness, the larger the number of air bubbles, the lighter the weight of each air bubble, and the more difficult it is for each air bubble to flow on the existing coating film 14 due to its own weight. As a result, it is estimated that the adhesiveness of the release agent 20 on the existing coating film 14 is improved, and as a result, the coating film thickness of the release agent 20 on the existing coating film 14 is increased. Further, the thicker the coating film thickness of the release agent 20, the more the release agent 20 is applied to the existing coating film 14 (also referred to as the coating amount, for example, the release agent 20 applied per fixed area (or fixed time)). (Defined as weight) increases.

The inventor's experiment, as the injection pressure, it was found that the range or scope of 30-40kg / cm ² of 30-60kg / cm ² is desirable. The numerical value is that the pattern in which the release agent 20 is sprayed from the spray gun 50 is the above-mentioned target spraying pattern, and the release agent 20 is not sufficiently atomized from the spray gun 50 (without being atomized). It is desirable to set it so that it reaches on the film 14.

(2) Additional effect of increasing the viscosity of the release agent 20

Generally, when a high-viscosity release agent is applied, unlike the case where a low-viscosity release agent is used, when the coating film of the release agent requires a thickness, the release agent flows in the coating film. It is prevented from dripping.

Experiments by the present inventor have revealed that the higher the viscosity of the release agent 20, the better the adhesiveness of the release agent 20 on the existing coating film 14.

Further, the experiment of the present inventor has revealed that it is desirable that the paint viscosity of the release agent 20 is as high as about 5 to about 16 Pa · s (20 ° C.).

(3) High degree of emulsification of release agent 20

According to the experiment of the present inventor, as the degree of emulsification of the release agent 20 is higher, the number of bubbles generated in the release agent 20 due to the collision with the existing coating film 14 increases and the bubbles become finer, and as a result, the existing coating film 14 The fact that the adhesiveness of the release agent 20 on the top is improved has been found.

Based on this finding, an emulsion, that is, an aqueous release agent (for example, the first remover in FIG. 2) was adopted as the release agent 20.

However, according to the experiments of the present inventor, even if the release agent 20 is a non-emulsion, that is, a solvent-based release agent (for example, the second to fourth removers in FIG. 2), the coating thickness of the release agent 20 is conventionally determined. It was found that the coating method, that is, the method using an air spray gun or the method using a brush coating, is thicker.

<Component composition of release agent 20>

The release agent 20 contains a main component, an auxiliary agent, and a thickener, regardless of the type.

The main component contains an organic solvent in order to swell the existing coating film 14 and facilitate peeling from the surface of the structure 12. Examples of the organic solvent include an alcohol-based high boiling point solvent, an ester-based organic solvent, and a complex cyclic organic solvent.

The auxiliary agent exists for stabilizing the properties of the release agent 20, and includes, for example, aromatic hydrocarbon solvents, terpenes and the like.

The thickener is present so that the release agent 20 can be applied on the existing coating film 14 in a predetermined amount to prevent dripping, and examples thereof include silicate compounds and organic bentonite.

<Variation of composition of release agent 20>

As shown in FIG. 2, in the present embodiment, there are four types of release agents 20 that can be applied onto the existing coating film 14 by the spray gun 50, such as the first to fourth removers.

Among them, the first remover is a water-based release agent (emulsion), while the second to fourth removers are solvent-based release agents (non-emulsion).

Furthermore, the 1st and 2nd removers show normal reactivity and are recommended for use in the high temperature period when the average temperature is higher than about 10 ° C, whereas the 3rd remover has an average temperature of less than about 10 ° C. Even in the low temperature period, it shows normal reactivity and its use is recommended.

Since the fourth remover contains dichloromethane, safety management measures are required to prevent health damage to workers, but it dries faster than other removers and exhibits strong peeling power. It is recommended that this fourth remover be used for partial repair.

1. 1. Solvent-based release agent

It contains an organic solvent as the main component (20-90%), and also contains an auxiliary agent, a thickener and the like as an auxiliary component.

2. Water-based release agent

It contains an organic solvent as a main component (30-50%), and also contains an auxiliary agent, a thickener and the like and water (35-50%) as auxiliary components.

In general, water-based strippers are less hazardous than solvent-based strippers.

An aqueous release agent is an emulsion in which a main component and water are emulsified using a surfactant.

<Foam type airless coating peeling method>

The foaming type airless coating peeling method according to the present embodiment includes the preparation step S100 shown in FIG. 3 and the construction step S200 shown in FIG. 4 in that order.

<Preparation process>

As shown in FIG. 3, first, in step S101, the operator investigates the existing coating film 14 to be peeled off. Specifically, the existing coating film factors such as the material, coating film thickness, and surface texture (for example, surface roughness μmRmax) of the existing coating film 14 and the structure factors such as the structure and shape of the structure 12 are investigated.

Next, in step S102, the operator selects the construction time for peeling off the existing coating film 14. If the construction time is selected, the average temperature of the environment at that construction time is predicted. The average temperature is referred to to determine which of the four types of removers described above is optimal.

Subsequently, in step S103, the operator selects the peeling condition. Specifically, one of the first to fourth removers in FIG. 2 is selected as the release agent 20 to be used this time, based on the above-mentioned existing coating film factor and / or structure factor for the existing coating film 14. .. At this time, as described above, the release agent 20 used this time is selected so as to have a viscosity suitable for deteriorating the atomization property of the release agent 20 in airless coating.

Further, it is determined how many times the peeling operation using the peeling agent 20 this time is repeated according to the factor including the investigated coating thickness. Further, the target coating film thickness of the release agent 20 in each peeling operation is determined based on the existing coating film factor and / or the structure factor described above.

Specifically, among the existing coating film factors, the release agent 20 is formed by being adhered to the surface of the existing coating film 14 according to the surface roughness (for example, unit: μmRmax) of the existing coating film 14. Determine the target coating film thickness (average coating film thickness, etc.) of the coating film to be applied.

More specifically, according to a predetermined relationship, the target coating film thickness of the release agent 20 is determined according to the surface roughness of the existing coating film 14, so that the smaller the surface roughness, the thicker the target coating film. ..

FIG. 8 is a graph conceptually showing an example of the relationship between the surface roughness of the existing coating film 14 and the target coating film thickness of the release agent 20. The lower the surface roughness, that is, the higher the surface smoothness, the more the total area in which the release agent 20 contacts the microscopic surface of the existing coating film 14 when the release agent 20 is applied to the surface of the existing coating film 14. (It is the total area of the microscopic surface in consideration of the surface unevenness, hereinafter referred to as "microscopic total contact area") is narrow.

The larger the total microscopic contact area for the projected area of the surface of the existing coating film 14 (that is, the total area of the macroscopic surface ignoring the surface unevenness), the more the release agent 20 can apply the existing coating film 14 at once. While the peeling speed is high, the narrower the total microscopic contact area is, the lower the speed at which the peeling agent 20 peels off the existing coating film 14 at one time, so that the peeling agent 20 takes more time. It is desirable to keep in contact with the existing coating film 14.

Therefore, in order to maximize the peeling speed of the release agent 20, the lower the surface roughness of the existing coating film 14, the thicker the coating film of the release agent 20 is, thereby making each part of the surface of the existing coating film 14 thicker. In addition, it is desirable that the release agent 20 laminated in the film thickness direction keeps contacting one after another from the portion close to the surface.

In addition, it may be assumed that the relationship between the surface roughness of the existing coating film 14 and the target coating film thickness of the release agent 20 is the opposite of that described above.

Specifically, the higher the surface roughness of the existing coating film 14, the larger the total microscopic contact area for the macroscopic total area. Therefore, the coating film of the release agent 20 is thickened to match it. It is also assumed that it is effective to increase the total coating amount by increasing the amount of the release agent 20 in contact with each part of the microscopic surface of the existing coating film 14 among all the parts. Can be done.

Further, the target coating amount is determined from the target coating thickness determined as described above. Further, the target discharge amount of the release agent 20 from the spray gun 50 is determined according to the determined target coating amount, and in some cases, the nozzle tip 92 to be used this time is selected. However, at this time, as described above, the nozzle tip 92 used this time is selected so as to have an equivalent diameter suitable for deteriorating the atomization property of the release agent 20 in airless coating.

Further, the spray gun 50 determines the injection pressure when the release agent 20 is pressurized and injected from the nozzle according to the viscosity of the release agent 20 this time and the target discharge amount of the release agent 20 from the nozzle. do. However, at this time, as described above, the injection pressure is selected so as to have a height suitable for deteriorating the atomization property of the release agent 20 in the airless coating.

<Construction process>

As shown in FIG. 4, first, in step S201, the operator implements the above-mentioned foam-type airless coating method on the existing coating film 14.

The foaming airless coating method includes a preparatory step in which the worker prepares or procures the release agent 20 and puts it into the tank 30, and the worker activates the pump 40. It has a pumping step of pumping the release agent 20 from the tank 30 to the spray gun 50 in an airless state.

In the foam type airless coating method, the operator further grasps the spray gun 50 and aims at the target, that is, the existing coating film 14, and pulls the trigger 96 in that state, whereby a plurality of release agents 20 are applied from the spray gun 50. It has an injection step of dividing into droplets and injecting them toward a target.

The injection step does not include a step of bringing the release agent 20 into contact with the flow of compressed air and atomizing the release agent 20 by the principle of atomization, and further, the release agent 20 is made before the release agent 20 is injected from the nozzle 92. Does not include the step of foaming.

The foam-type airless coating method further includes a coating step in which the operator applies the sprayed release agent 20 on the surface of the existing coating film 14.

In the coating step, during the coating, the plurality of droplets of the release agent 20 collide with the surface of the existing coating film 14, whereby the plurality of droplets entrain air in the atmosphere and foam. As a result, the release agent 20 is applied onto the surface of the existing coating film 14 in a foamed state.

In one example, the release agent 20 is previously applied so that the coating step has a plurality of bubbles in which the foamed release agent 20 has an average diameter in the range of about 0.1 mm to about 0.5 mm. It is carried out so as to be applied on the surface of the film 14.

In another example, the release agent 20 is such that in the coating step, the average coating film thickness of the coating film formed by the release agent 20 being applied onto the surface of the existing coating film 14 is about 1 mm. Is applied onto the surface of the existing coating film 14.

In yet another example, in the coating step, the average coating film thickness of the coating film formed by the release agent 20 being applied onto the surface of the existing coating film 14 is within the range of about 2 mm to about 5 mm. As shown in the above, the release agent 20 is applied onto the surface of the existing coating film 14.

In any of the examples, the existing coating film 14 is swollen and softened by the release agent 20, and the adhesive force of the structure 12 to the surface is reduced, and as a result, the existing coating film 14 is lifted from the surface of the structure 12.

Next, in step S202, after the application of the release agent 20 is completed, the operator wraps the surface of the existing coating film 14 with a protective sheet having impermeable to the release agent 20, whereby the release agent 20 ( It prevents the vaporized gas generated from (when it is volatile) from being released into the atmosphere from the surface of the existing coating film 14. The protective sheet is, for example, a flexible polyethylene sheet, a polypropylene sheet, or the like.

According to the experiment of the present inventor, as an effect of the wrapping, the release of vapor (vaporized gas) from the release agent 20 applied on the existing coating film 14 is prevented, whereby about 90% of the vapor is released from the existing coating film. It was confirmed that it penetrated into 14 and promoted the efficiency of the peeling work.

Subsequently, in step S203, after the required time (for example, 16-48 hours) has elapsed from the completion of the coating, the operator peels off the protective sheet from the existing coating film 14 and removes it. After that, the operator physically peels off the existing coating film 14 that has been lifted from the surface of the structure 12 due to the adhesive force reduced by the release agent 20 from the structure 12 and removes it.

In order to physically peel off the existing coating film 14 from the structure 12, the operator may use a scraper as a hand tool.

Further, in order to remove the coating film residue which is a part of the existing coating film 14 remaining on the surface of the structure 12 after the first peeling operation, a wire brush as an electric rotary tool (for example, a cup-shaped wire brush) is used. ) Or an air grinder may be used.

Since this removal work imposes a heavy burden on the operator, it is important that the electric rotary tool is as light as possible and that the peeled coating film residue does not scatter. Therefore, it is desirable that the electric rotary tool is small and the rotating portion rotates at a lower speed than usual.

In addition, if desired, the operator may use an additional or alternative high pressure washer to remove the existing coating film 14 and / or coating film residue.

According to the present embodiment, in order to achieve the target coating thickness of the release agent 20, a brush or a roller requires a plurality of coating operations, but the target coating thickness is set to once. This can be achieved by coating work, and work efficiency is improved.

Further, in the present embodiment, the release agent 20 is installed in-line from the installation location (in FIG. 1, the main body portion of the airless coating machine 10 excluding the spray gun 50 is fixedly installed) (work with the main body portion). The spray gun 50, which is a place, can be fed to the work place (in a state of being connected to each other by a continuous pumping line 78).

Specifically, the main body (particularly, the pressure pump 40) and the spray gun 50 of the airless coating machine 10 are connected to each other by a hose (line) 78 that serves as both a pressure transmission path and a material supply path. .. As a result, unlike the case of air coating (spray coating), the main body (particularly, the pressure pump 40) and the spray gun 50 can be connected to each other by both a pressure transmission path and a material supply path that are independent of each other. It becomes unnecessary.

As a result, the release agent 20 can be reliably supplied to the spray gun 50. Specifically, the release agent 20 is unplanned while the release agent 20 is being supplied from the main body to the spray gun 50. It will not leak to the work floor or the like and the part will not be contaminated with the release agent 20.

<Adhesiveness test>

Types of release agent 20 used in the adhesiveness test

The type of the release agent 20 used in the coatability test is the first remover (high viscosity emulsion) shown in FIG. A specific example of the first remover has the following component composition.

Moisture: 40-50% by weight
Alcohol solvent: 40-50% by weight
Petroleum solvent: 1-5% by weight
Surfactant: 1-5% by weight
Thickener: 1-5% by weight
Rust prevention: less than 1% by weight Waxes: less than 1% by weight

Moreover, the specific example has the following properties.

Appearance: Viscous liquid showing white or pale yellow Viscosity: 5-16 Pa · s (20 ° C)

Example

260 g of release agent 20 and a spray gun 50 were airlessly applied to a 500 × 500 mm steel sheet for coating as a test piece, whereby a coating amount (coating density, spraying density) ^{of 1.0 kg / m 2 was applied to the test piece.} Was realized.

After the application, the test piece was hung vertically, and the test piece was photographed after 5 minutes in order to observe the dripping condition of the release agent 20. The photograph is attached to the upper part of FIG.

Comparative example

260 g of release agent 20 and a brush (not shown) are applied to a 500 × 500 mm steel sheet for coating as a test piece, whereby ^{a coating amount of 1.0 kg / m 2} (coating density, spraying) is applied to the test piece. (Density) has been achieved.

After the application, the test piece was hung vertically, and the test piece was photographed after 5 minutes in order to observe the dripping condition of the release agent 20. The photograph is attached to the bottom of FIG.

Contrast observation

In the examples, dripping of the release agent 20 (for example, unplanned behavior of the release agent 20 due to gravity such as traces of the release agent 20 flowing and dropping of the release agent 20) could not be observed at all. The surface of the release agent 20 applied to the test piece was smooth.

As is clear from the upper photograph of FIG. 6, in the examples, it was confirmed that the release agent 20 applied to the test piece did not flow down from the test piece at all.

Further, the average coating thickness of the release agent 20 adhered to and fixed to the test piece without dripping from the test piece (for example, the coating thickness when applied only once without recoating) is about 2 mm to about. It was also confirmed that it was within the range of up to 5 mm.

Furthermore, it was also confirmed that the release agent 20 in a foamed state on the test piece had a plurality of bubbles having an average diameter in the range of about 0.1 mm to about 0.5 mm.

On the other hand, in the comparative example, dripping (or flow, flow line) of the release agent 20 was observed over the entire test piece. Further, on the surface of the release agent 20 applied to the test piece, a material flow occurred and a streak-like uneven pattern was present.

As is clear from the photograph at the bottom of FIG. 6, in the comparative example, it was confirmed that a part of the release agent 20 applied to the test piece flowed down from the test piece.

In addition, in order to confirm the effect of the present embodiment, the present inventor has described a steel tower as a building having a surface on which the release agent is difficult to spread due to its complicated shape. The peeling work was actually performed using the foaming type (foaming promotion type) airless coating peeling method according to the embodiment. As a result, it was confirmed that the peeling work was ensured, that is, the existing coating film was peeled to every corner, and that the efficiency was improved, that is, the time for the peeling work was shortened.

Further, in the above description of the present embodiment, the phenomenon that the release agent 20 foams is referred to as static air in the process in which the release agent 20 ejected from the spray gun 50 flies in the static air. The plurality of droplets split from the release agent 20 do not become air bubbles due to the collision with the existing coating film 14, and only when the plurality of droplets collide with the existing coating film 14, the plurality of droplets become air bubbles and the release agent 20 foams on the existing coating film 14. It was described as an aspect of doing so.

However, in the process in which a plurality of droplets of the release agent 20 fly in static air, the present invention may be carried out in such a manner that at least a part of the droplets becomes air bubbles due to collision with static air. Do not exclude.

[Second Embodiment]

Next, an exemplary second embodiment of the present invention will be described in detail with reference to the drawings. However, with respect to the elements common to the first embodiment, redundant description will be omitted by quoting using the same name or reference numeral, and only different elements will be described in detail.

FIG. 9 shows an example of a coating film peeling method according to the present embodiment in a process diagram.

In this coating film peeling method, wet peeling as an example of the chemical removal method is carried out in step S1. This wet peeling may be the same as or different from that according to the first embodiment described above. For example, this wet peeling may be carried out in a mode in which the peeling agent is applied onto the existing coating film 14 by an airless spray method of a type that does not foam at all or promotes foaming.

In this coating film peeling method, high-pressure cleaning as an example of the physical removal method is subsequently carried out in step S2. This high pressure cleaning is carried out in combination with the wet peeling as a previous step, but may be carried out alone.

In the present embodiment, in order to carry out the high-pressure washing, a coating film configured to wash the surface of the structure 12 by high-pressure injection of washing water and physically remove the existing coating film 14 from the surface. A removal high pressure cleaning system (hereinafter simply referred to as "high pressure cleaning system") 100 is used. The high pressure cleaning system 100 will be described in detail later with reference to FIGS. 10-19.

In this application, the term "washing water" is not a term chosen with the intent of eliminating liquids other than water, and is commonly used as synonymous with the term "washing liquid". NS.

In this coating film peeling method, after that, in step S3, the cleaning water (usually synonymous with the cleaning liquid) ejected from the cleaning gun 110 (see FIG. 10) in the high-pressure cleaning system 100 is wastewater (conventional wastewater). Wastewater treatment is carried out to collect and treat as (synonymous with). The cleaning gun 110 will be described in detail later with reference to FIGS. 10-16. A wastewater treatment unit 200 is used to carry out the wastewater treatment. The wastewater treatment unit 200 will be described in detail later with reference to FIGS. 17-19.

Here, in the present embodiment, the technical background of combining the wet peeling with the high-pressure washing and the wastewater treatment will be described.

Generally, as a method of removing an existing coating film (old coating film) that has been softened and swollen on the surface of a structure by a release agent and has risen from the surface, a scraper as a hand tool, a rotary tool, or the like is used by an operator. By using it manually, and by contacting a rigid member such as a wire brush or a scraper with a narrow machining area on the surface of the structure, the rigid member scratches, scrapes, or polishes the machining area. A method of removing the existing coating film from the surface of the structure has already been proposed.

On the other hand, in general, a high-pressure cleaning method in which an operator sprays cleaning water at high pressure to remove an existing coating film has already been proposed. This high-pressure cleaning method is a cleaning method in which the existing coating film is peeled off by using the impact force of water, and by extension, the existing coating film is washed away, and the surface of the structure is not directly rubbed.

This high-pressure cleaning method has an advantage over the above-mentioned method of removing a coating film using a scraper or a rotary tool, because it does not rub the surface of the structure directly, so that the surface of the structure is not damaged. Since the area that can be washed at one time is wide, there is an advantage that the removal work is highly efficient.

In addition, this high-pressure cleaning method is essentially a constriction that cannot be penetrated by a rotary tool, and complex shapes such as around bolts and nuts (for example, rotary tools such as rotary wire brushes and rotary files are not points but surfaces. Since it comes into contact with the surface of the structure, the tool contact point when the rotating tool comes into contact with the structure cannot be moved as freely as in the case of point contact, which makes it difficult to remove the coating film). Even if is present in the structure, there is an advantage that the cleaning water is applied around the complex part of the shape, whereby the existing coating film can be completely removed.

However, at present, the latter method has not been put into practical use. This is because the high-pressure jetted wash water may scatter before colliding with the structure and may scatter when it collides with the structure and bounces off. The amount of cleaning water required for the work may increase and the work efficiency may decrease, and the cleaning water scattered when it bounces off the structure is contained in the existing coating film or the plating layer of the base material of the structure. This is because if the harmful substances are mixed in, the harmful substances may be scattered along with the scattering of the washing water, which may pollute the environment.

Therefore, in the present embodiment, the high-pressure cleaning method is realized in a state where the above-mentioned potential drawbacks are overcome while maintaining the above-mentioned essential advantages.

Specifically, the high-pressure cleaning system 100 reduces the impact of harmful substances on the environment, that is, the harmful substances are substantially (for example, practically acceptable) in relation to the environment. To achieve detoxification
(1) The cleaning gun 110 is configured so that the cleaning water after injection does not scatter from the scaffold 210 (see FIG. 13), and further.
(2) When the wastewater treatment unit 200 collides with the structure 14 and rebounds, the cleaning water and the coating film mixed therein do not deviate from the scaffold 210 even if they are scattered. It is configured to be virtually entirely captured and detoxified.

<Washing gun>

In FIG. 10, the cleaning gun 110 is shown in a partial cross-sectional side view.

The cleaning gun 110 has a main body portion 112 and a hollow tubular portion 114, and the base end portion of the tubular portion 114 is connected to the main body portion 112.

The main body 112 has a flow control valve (valve opening: 0% fully closed-100% fully open) 120. The flow control valve 120 is fluidly connected to a high pressure source (for example, a pump) 124 via a flexible hose 122, and is also fluidly connected to a fluid passage 126 in the cylinder 114. The high pressure source 124 pumps cleaning water before use from the tank 125.

The main body 112 further has a grip 130 that is gripped by one hand of the operator and a trigger 132 that is operated by the fingers of the same hand. The flow rate control valve 120 is turned on and off according to the operation position of the trigger 132, and the valve opening degree of the flow rate control valve 120 is adjusted in the on state (valve opening degree is larger than 0%).

In the present embodiment, the cleaning gun 110 adjusts the injection pressure by adjusting the injection water amount, which is the amount of cleaning water injected from the cleaning gun 110 in the on state (for example, fully open state) of the flow control valve 120. It has an injection pressure regulator (valve opening: 0% fully closed-100% fully open) 140. The operator can operate the injection pressure adjuster 140 at the same time with the other hand while pulling the trigger 132 with one hand.

Here, the injection pressure adjusting tool 140 is also a mechanism for adjusting the amount of injected water. This is because a certain interlocking relationship is established between the two, such that the injection pressure decreases as the injection water amount decreases, and conversely, the injection pressure increases as the injection water amount increases.

In one example, the injection pressure adjuster 140 has an operating portion 142 that is manually rotated by an operator, and the injection pressure adjuster 140 is mounted in the middle of the tubular portion 114.

By the way, assuming a site where an operator performs high-pressure cleaning of a structure 12, the properties of the existing coating film 14 to be removed (for example, for each work site (individual target cleaning surface) of the structure 12). The higher the degree of adhesion to the structure 12, the higher the injection pressure is required) and the shape of the structure 12 (for example, the more complicated the shape, the more frequently the direction in which the cleaning water hits the cleaning surface fluctuates. Since the amount of scattering increases, the injection pressure is lowered to reduce the amount of jet water). On the other hand, in order to preserve the environment, it is important to minimize the amount of each of the washing water and the coating film pieces scattered.

Therefore, in the present embodiment, during the series of work, the worker sprays the cleaning water at a high injection pressure for one work part in order to prioritize the removal of the coating film, while the worker scatters the other work part. In order to inject cleaning water at a low injection pressure to prioritize prevention, the operator frequently operates the injection pressure regulator 140 during work, i.e., with the cleaning gun 110 continuously on. It is possible to do.

<Injection nozzle>

The cleaning gun 112 has a nozzle portion 150 connected to the tip end portion of the tubular portion 114. The nozzle portion 150 has a hollow nozzle cover 152 connected to the tip end portion of the tubular portion 114 and a nozzle tip 154 detachably attached to the nozzle cover 152 in a state of being fluidly communicated with the fluid passage 126. Have.

As shown in FIG. 11B, the nozzle tip 154 is formed with an injection nozzle 156, and the injection nozzle 156 is an injection hole as an outlet for injecting and discharging cleaning water at a high pressure. Has 160.

In the present embodiment, the injection nozzle 156 is configured to realize a flat spray and a fan-shaped spray (spray pattern) as illustrated in FIG. 11A. Specifically, the injection hole 160 has an elongated rectangular shape having a hole width W, as illustrated in FIG.

<Food>

As shown in FIG. 10, the cleaning gun 110 has a hood 170 detachably attached to the tip of the tubular portion 114. The hood 170 is attached to the cleaning gun 110 so as to extend from the injection nozzle 154 in the injection direction while covering the injection nozzle 154.

As a protective device attached to the tip of the cleaning gun 110, the hood 170 prevents the cleaning water injected in the form of mist from the injection nozzle 154 from scattering laterally, as illustrated in FIG. It is configured as follows. Further, the hood 170 captures the wash water that collides with the surface of the structure 12 and bounces after injection, thereby reducing the amount of the bounced wash water scattered.

That is, the hood 170 captures the washing water that scatters immediately after the injection and also catches the washing water that collides with the surface of the structure 12 and bounces off after the injection, whereby the washing water before and after the collision is scattered. It has the function of reducing the amount.

<Outer shape of hood>

As shown in FIG. 10, the hood 170 generally has a divergent conical shape as a whole, and specifically, a base end portion 172 attached to the tip end portion of the tubular portion 114 and a base end portion 172 thereof. It has a cone portion 174 extending in a divergent shape from the tip surface of the surface. The axial length A of the cone portion 174 is about 100-about 150 mm, and the maximum diameter B of the cone portion 174 is about 150 mm.

In the present embodiment, there are a plurality of types of hoods 170, which are selected by the operator according to the situation at the site and the shape of the work target portion in the structure 12, and the selected type. Hood 170 is attached to the cleaning gun 110.

<Cross-sectional shape of hood>

As the plurality of types of hoods 170, although not shown, a conical type having a circular cross section in which the cone portion 174 gradually increases in diameter as it advances in the axial direction, and a conical type having a circular cross section, as illustrated in FIGS. 12 and 13, are outside the radial direction. There is a modified conical type having a non-circular cross section formed by combining a triangular shape that is convex in the direction and a partial circle.

Here, the cross section of the cone portion 174 belonging to the "cone type" may be circular, elliptical, oval, or polygonal.

Further, the "non-circular cross section" is, for example, a shape formed by combining a semicircle and a triangle (for example, a right-angled triangle, a triangle having a generally right-angled apex angle, etc.) at the diameter of the semicircle and the base of the triangle. Or a fan-shaped cross section having a central angle that is generally a right angle.

In any case, as illustrated in FIG. 12 (a), the "non-circular cross section" is a corner portion (for example, a cross-sectional area) at at least one point in the circumferential direction in each cross section of the cone portion 174 of the hood 170. A cross section that is partially non-circular so as to have a sudden change portion, eg, a right angle portion) 176, while at least one other portion has a partial circumferential portion 178 (eg, a semicircle, an arc, etc.). ..

On the other hand, the "non-circular cross section" has a corner portion at at least one position in the circumferential direction in each cross section of the cone portion 174 of the hood 170, while the curved portion other than the arc is formed at at least one other location. For example, it may mean a cross section that is totally non-circular so as to have a partial ellipse, a partial oval, etc.).

Here, in each cross section, the number of corner portions 176 may be one, two, or three or more. Further, in each cross section, any of the two sides 179,179 constituting one corner portion 176 and abutting against each other may be a straight line, one may be a straight line, and the other may be a curved line. May also be a curve.

Further, in each cross section, the internal angle (angle of the inside corner) of the corner portion 176 may be a right angle, an acute angle, or an obtuse angle.

FIG. 12A shows the hood 170 in a front view, and FIG. 12B shows a cross-sectional view of the base end portion 172 of the hood 170. The cross section of the cone portion 174 of the hood 170 at each axial position is shown in FIG. It gradually changes to what is shown.

<Materials that make up the hood>

The hood 170 is made of a material having elasticity (property of being morphologically flexible so as to have high followability to the shape of the mating member and having shape restoration property) at least at the tip portion.

Thanks to its elasticity, the cleaning gun 110 is horizontal in at least a portion of the tip of the hood 170 (eg, in the example shown in FIG. 13C), as will be detailed later with reference to FIG. On the structure 12 when the side (tip edge) 179 extending to the surface and the side (tip edge) 179) extending vertically are in contact with the surface of the structure 12 and are moved along the surface to be swept. Obstacles (for example, the exposed bolt 190 in the example shown in FIG. 13) can be overcome by elastic deformation.

As a result, the operator does not need to change the distance between the cleaning gun 110 and the structure 12, that is, the injection distance D so as to escape the obstacle every time such an obstacle appears. If the injection distance D is maintained, the injection pressure does not fluctuate due to the change in the injection distance D, whereby the cleaning ability of the cleaning gun 110 is stably maintained during high-pressure cleaning.

As the material of the hood 170, an elastic body or an elastomer may be selected as a single material for the entire hood 170, or silicone (for example, rubber-like silicone) may be selected as the elastic body or the elastomer.

Further, the material of the hood 170 may have different materials for the tip portion of the hood 170 (the portion in contact with the structure 12) and the other portion. For example, the tip portion of the hood 170 is an elastic body. , You may choose a composite material such that the rest is rigid.

In the example of this composite material, it becomes easier to connect the hood 170 to the tubular portion 114 more firmly than when the entire hood 170 is configured as an elastic body, and the bending rigidity of the hood 170 is improved, and as a result, the bending rigidity of the hood 170 is improved. Since the tip of the hood 170 bends from the rear end as a whole against the will of the operator, the possibility that it becomes difficult to aim the cleaning gun 110 is reduced.

<Visibility to the washed part of the hood>

The material of the hood 170 is preferably selected so that it has at least partial light transmission at least at the tip of the hood 170.

Thanks to its light transmission, the operator can use the hood 170 to position a momentary work object or cleaning site (eg, the exposed bolt 190 in the example shown in FIG. 13) within the hood 170 during work. The operator's line of sight optically penetrates the hood 170, thus allowing the operator to actually see the area to be cleaned inside the hood 170, even though visual access to the area to be cleaned may be blocked. It is possible to visually check or monitor the behavior of the washing water colliding with the washing water in real time based on the shape of the washing part.

<Elastic overcoming characteristics of obstacles due to the hood>

FIG. 13A is a perspective view showing how the hood 170 conforms to the inside corner 182 (cleaning surface to be cleaned) of the angle member 180 in the structure 12 to be worked. Has been done. Specifically, in this example, the two sides (two surfaces) 179 and 179 forming the corner portion 184 of the cone portion 174 of the hood 170 are line-contacted or surfaced with the two surfaces of the corresponding inside corners 182, respectively. Contact.

In FIG. 3B, the cone portion 174 of the hood 170 was fastened to the angle member 180 in the process in which the cleaning gun 110 was moved (followed) along the inside corner 182 of the angle member 180 by the operator. A side view shows how the exposed portion 190 of the bolt is overcome by its own elastic deformation in chronological order.

Specifically, the cone portion 174 approaches the bolt exposed portion 190 on the side 179 of the cone portion 174 while contacting the upward surface of the inside corner 182. Subsequently, when the cone portion 174 comes into contact with the bolt exposed portion 190, the portion of the cone portion 74 that comes into contact with the bolt exposed portion 190 elastically gets over the bolt exposed portion 190. After that, when the cone portion 174 completes overcoming the bolt exposed portion 190, the cone portion 174 is restored to its original shape by its own elasticity.

As a result, even if an obstacle such as the bolt exposed portion 190 exists on the moving (sweeping) path of the cleaning gun 110, the cleaning gun 110 can elastically overcome the obstacle. It is possible to move along the inside corner 182 while performing high-pressure washing and peeling of the surface of the inside corner 182 while maintaining the height position of the inside corner 182. As a result, the burden on the operator who operates the cleaning gun 110 is reduced, and thereby the work efficiency is improved.

FIG. 3C is a front view showing how the cone portion 174 of the hood 170 elastically deforms itself when it gets over the exposed bolt portion 190.

<Other effects due to the elasticity of the hood>

In this embodiment, as described above, the hood 170 has elasticity at least at its tip. As a result, the operator is in a state where the hood 170 is at least partially in contact with the surface of the structure 12 at its tip (eg, the hood 170 is almost entirely on the surface of the structure 12 around its tip. The aiming direction and aiming point of the cleaning gun 110 without changing the overall position of the hood 170 in contact (in a state where the injection space in the hood 170 is substantially shielded by the surface of the structure 12). It is possible to change the position of, that is, to manipulate the angle and the position. This will be specifically described below.

The structure 12 may have a protrusion on its surface, and an example of the protrusion is the bolt described above with reference to FIG. When the protrusion is an object having a three-dimensional shape such as a bolt, the peripheral portion of the protrusion (for example, the outer peripheral surface of the protrusion and the protrusion of the surface of the structure 12) It may be necessary to perform high pressure cleaning of the annular region adjacent to the periphery, that is, for example, around the bolt.

If the hood 170 is a rigid body for high-pressure cleaning around the bolt, if the hood 170 comes into contact with the bolt or its peripheral members, the angle operation and the position operation of the cleaning gun 110 will be hindered. Therefore, the operator revolves the momentary aiming point of the cleaning gun 110 along the bolt peripheral portion so that the hood 170 does not come into contact with the structure 12, and the grip portion 130 of the cleaning gun 110 is the bolt center line. Complex work is required, such as operating the cleaning gun 110 so that it revolves around.

On the other hand, if the hood 170 has elasticity at least at the tip portion, even if the hood 170 comes into contact with the bolt or its peripheral members, the angle operation and the position operation of the cleaning gun 110 are not hindered, so that the operator Is revolving along the bolt circumference at the momentary target of the cleaning gun 110 so that the hood 170 remains in contact with the structure 12 (and as a result the injection distance D is also maintained). , Only a simple operation such as operating the cleaning gun 110 is required so that the cleaning gun 110 swings.

Therefore, according to the present embodiment, since the hood 170 has elasticity at least at the tip portion, the movement form thereof is simplified with respect to the operation required for the operator to perform high pressure cleaning of the bolt peripheral portion with the cleaning gun 110. , The effect that the burden on the worker is reduced and the work efficiency is improved can be obtained.

<Cleaning power characteristics of cleaning gun>

FIG. 14 (a) conceptually shows the relationship between the amount of injected water and the impact pressure as a plurality of cleaning force characteristics of the cleaning gun 110, and FIG. 14 (b) shows the injection angle θ. The relationship with the impact pressure is conceptually represented by a graph.

Here, the "injection water amount" means the amount of water (L / min) per unit time of the cleaning water injected from the injection nozzle 154 of the cleaning gun 110. ^{Further, the “impact pressure” means the pressure (kgf / cm 2} ) generated on the surface of the structure 12 due to the collision of the cleaning water jetted from the cleaning gun 110 with the surface of the structure 12. Further, as illustrated in FIG. 11A, the “injection angle” means the apex angle θ of the fan-shaped spray pattern drawn by the cleaning water when the cleaning water is ejected from the injection nozzle 154.

As shown in FIGS. (A) and (b), in the cleaning gun 110, the larger the amount of injected water, the higher the impact pressure, and the smaller the injection angle θ, the higher the impact pressure.

FIG. 15 (a) conceptually shows the relationship between the injection pressure and the impact pressure as a plurality of different cleaning force characteristics of the cleaning gun 110, and FIG. 15 (b) shows the injection distance. The relationship between D and the impact pressure is conceptually represented by a graph.

Here, the "injection pressure" means the pressure generated in the cleaning water when the cleaning water is injected from the injection nozzle 154 (for example, the pressure in the injection nozzle 154). Further, the “injection distance” means the distance D between the injection nozzle 154 and the collision surface of the cleaning water, that is, the target cleaning surface, as illustrated in FIG. 11A.

As shown in FIGS. (A) and (b), in the cleaning gun 110, the higher the injection pressure, the higher the impact pressure, and the shorter the injection distance, the higher the impact pressure.

FIG. 16 conceptually shows a plurality of locations and a plurality of directions in which the cleaning water is scattered when the cleaning gun 110 injects the cleaning water and collides with the cleaning surface in a state where the hood 170 is not attached. It is represented in the figure.

If the amount of washed water that is sprayed before it hits the washing surface is reduced, the amount of washing water that bounces off the washing surface after it hits the washing surface is also reduced, and the amount of washing water that is scattered is also reduced. The amount of the coating piece scattered in the scattered cleaning water is also reduced.

Therefore, in the present embodiment, the cleaning gun 110 is provided with a hood 170 for preventing the cleaning water from scattering to the side immediately after the injection during high-pressure cleaning.

Further, in the present embodiment, during high-pressure cleaning, the operator moves the cleaning gun 110 along the cleaning surface while contacting the cleaning surface at at least a part of the tip portion of the hood 170. That is, a contact mode in which the cleaning gun 110 is swept while contacting the cleaning surface in the hood 170 is realized.

As a result, in the present embodiment, during high-pressure cleaning, the adhesion between the hood 170 and the angle member 180 as the cleaning portion is increased, and the unnecessary clearance between the two is reduced. Therefore, even if the washing water collides with an area laterally deviated from the regular washing area and tries to scatter to bounce off the area, the washing water to be scattered is captured by the hood 170.

Therefore, during high-pressure washing, in the contact mode, the washing water that is about to bounce off the structure 12 and scatter is captured by the hood 170, and as a result, the coating piece removed from the structure 12 by the collision with the washing water is released. The amount of water carried and scattered by the bouncing wash water is also reduced. This effect is achieved independently of the reduction in the amount of washed water scattered before the collision.

Further, in the present embodiment, during high-pressure cleaning, if the operator moves the cleaning gun 110 along the cleaning surface while contacting the cleaning gun 110 with at least a part of the tip portion of the hood 170, the operation is performed. The actual injection distance D of the cleaning gun 110 is maintained substantially constant without the person being particularly aware of it. As a result, the injection pressure is also maintained substantially constant, thereby stabilizing the effect of the high pressure injection.

<New idea of jet scraper>

By the way, the simplest approach to increase the impact pressure of the cleaning gun 110 is to increase the amount of water jetted by the cleaning gun 110. However, as the amount of jet water increases, the amount of water used by the cleaning gun 110 may increase and work efficiency may decrease, and as the amount of jet water increases, the amount of washing water scattered and the coating film pieces scattered during high-pressure washing. The amount may increase.

Therefore, in the present embodiment, in order to increase the impact pressure, an approach is taken in which the injection pressure is increased, the injection distance is shortened, and the injection angle is reduced while minimizing the amount of injected water.

Further, in the present embodiment, the injection (spraying) of the washing water is realized as a flat blowing (fan-shaped spraying), and the hole width W, which is the width dimension of the injection hole 156 of the injection nozzle 154, is minimized, thereby. The wash gun 110 is designed so that the wash water collides with the wash surface in an elongated, momentary wash area that is neither circular nor oval, thereby increasing the impact pressure while minimizing the amount of spray water.

Further, in the present embodiment, the cleaning gun 110 being injected is swept over the cleaning surface in a direction intersecting the cleaning area thereof, thereby cleaning having a generally one-dimensional shape. The area is developed into a cleaning area having a two-dimensional or three-dimensional shape.

Therefore, the tip of the spray pattern from the cleaning gun 110 that collides with the cleaning surface is originally composed of a morphologically variable fluid, but is in an elongated instantaneous cleaning region and is exposed to the cleaning surface at high pressure. The unique cleaning method in this embodiment is referred to as a "jet scraper" because it has the same function as a scraper as a rigid body that does not change its shape as a result of collision.

In addition, this concept of jet scraper may be adopted in combination with a cleaning gun different from the cleaning gun 110, in combination with a completely different cleaning gun that does not correspond to the cleaning gun, or adopted alone. Is possible.

Further adding, in the above example, the cleaning gun 110 is used in a contact mode in which the hood 170 moves while in contact with the surface of the structure 12, but is non-contact moving without such contact. May be used in mode.

If the cleaning gun 110 is used in the contact mode, the effect of reducing the amount of the cleaning water scattered immediately after the injection can be obtained. On the other hand, if the cleaning gun 110 is used in the non-contact mode, the effect of reducing the amount of scattered cleaning water immediately after injection can be obtained.

For the same structure 12, all scheduled cleaning surfaces thereof may be cleaned only in contact mode, or all scheduled cleaning surfaces may be cleaned only in non-contact mode. Also, for the same structure 12, of all the planned cleaning surfaces of it, one area is cleaned in contact mode, another area is cleaned in non-contact mode, and so on, during a series of high pressure cleaning. The mode to be used may be switched alternately between the contact mode and the non-contact mode.

Against the background of the circumstances described above, with respect to the cleaning gun 110, five main design variables are embodied as follows in order to realize the jet scraper described above.

Injection pressure: about 80- to about 250 kgf / cm ² (e.g., ultra high pressure region (e.g., high-pressure injection region does not reach the region) of more than 800 kgf / cm ² or 1,000 kgf / cm ²⁾

Injection distance D: about 50-about 200 mm (eg, proximity injection area not exceeding 200 mm or 300 mm)

Injection angle θ: Approximately 10 to 15 degrees (for example, a narrow angle injection region that does not exceed 20 degrees)

Jet water volume: Approximately 8-about 20 L (liter) / min (eg, small water volume injection region not exceeding 30 L / min, 40 L / min or 50 L / min)

Hole width (nozzle width) W: Approximately 0.2-Approximately 0.6 mm (for example, a narrow injection region that does not exceed 0.7 mm, 1 mm, or 2 mm)

By selecting these values, the cleaning gun 110 realizes high pressure injection, proximity injection, narrow angle injection, small amount of water injection and narrow width injection.

In short, in the present embodiment, as a coating film removing high-pressure cleaning method for removing the existing coating film 14 from the surface of the structure 12 by injecting cleaning water at high pressure to clean the surface of the structure 12. Those having the following several steps are carried out.

High-pressure injection step: By operating the cleaning gun 110, cleaning water is injected at high pressure from a flat-blowing injection nozzle 154 in a fan-shaped spray pattern, whereby the cleaning water is sprayed from the structure 12 in an elongated instantaneous cleaning region. Collide with the surface.

Sweeping step: By sweeping the cleaning gun 110, the instantaneous cleaning area is moved in a direction intersecting it, thereby making the one-dimensional instantaneous cleaning area two-dimensional on the surface of the structure 12. Alternatively, it is developed in a three-dimensional cleaning area.

The present inventor uses a prototype of the cleaning gun 110 to physically remove the steel tower as an example of the structure 12 by the high-pressure cleaning this time after chemically removing the coating film using a release agent. A test was conducted to confirm the effect of the high pressure cleaning.

As a result of the test, the present inventor confirmed the following multiple effects.

1. 1. Compared to the case where physical removal is performed manually or using a rotating tool, the work content is simplified and the work time is shortened, which reduces the number of workers required and the load on each worker. ..

2. Since the object applied to the structure 12 for physical removal is water, which is a flexible fluid (highly followable to the mating object), the range of target parts that can be removed from the coating film is limited to each target part. The coating film was satisfactorily removed even in the narrowed portion, the complicated shape portion, and the difficult work portion of the structure 12, without being limited by the shape of the structure 12.

3. 3. The galvanized layer, which is the base material of the structure 12, was not damaged, and therefore good base material adjustment was performed for the structure 12.

4. Since the release agent applied to the structure 12 prior to the high-pressure cleaning is also removed, it is possible to avoid the occurrence of poor paint adhesion during the subsequent repainting of the structure 12 due to the residual amount of the release agent. Was done.

5. The cleaning work normally performed on the structure 12 can be omitted prior to the repainting performed on the structure 12 after the coating film removing work is completed.

6. Prior to high-pressure cleaning, it is sufficient to unload the cleaning gun 110 and hose 122 to a high place, which is the work place of the tower, with the high-pressure source 124 installed on the ground, and as a result, it should be brought to that high place. The number and weight of tools and equipment has been reduced.

In addition, there is a trade-off between multiple effects when setting the injection pressure. That is, if the injection pressure is set high, the existing coating film 14 is more reliably removed from the surface of the structure 12, but the amount of scatter of the cleaning water and the coating film pieces tends to increase.

However, in the present embodiment, the high-pressure cleaning is not performed independently on the surface of the structure 12, but the swelling and softening by applying the release agent is performed on the existing coating film 14 prior to the implementation. Therefore, it becomes easy to achieve the same coating film removing effect by high-pressure cleaning at a lower injection pressure.

Further, in the present embodiment, the cleaning gun 110 is used to inject cleaning water at an injection pressure that does not reach the ultrahigh pressure region to perform high pressure cleaning, but instead of this, the same cleaning is performed. The gun 110 may be used to perform high pressure cleaning by injecting cleaning water at an injection pressure belonging to an ultrahigh pressure region. In this sense, the term "high pressure" is interpreted herein to include the concept of "ultra-high pressure".

<Wastewater treatment unit>

FIG. 17A shows an example of the double sheet 202 as a part of the wastewater treatment unit 200 used for carrying out the wastewater treatment in FIG. 9 in a perspective view together with the scaffold 210. In (b), the water collecting sheet 222 of the double sheet 202 is shown in a side view.

As is well known, the scaffold 210 is suspended (supported) by a plurality of pillars 212 extending vertically from the ground as an example of a supporting surface (foundation surface) and the pillars 212 in a horizontally extending posture. ) A plurality of flooring materials 214 including one that supports the operator's feet from below and enables the operator to perform high-pressure cleaning work using the cleaning gun 110, and a plurality of handrails (not shown). It is configured to have a member of.

Although not shown, the scaffold 210 is provided as a scaffold for a worker who cleans and peels off a structure 12 which is an example of an object to be cleaned, so that the scaffold 210 is usually on the ground and adjacent to the structure 12. Will be installed.

The double sheet 202 is installed on the scaffold 210 installed on the structure 12 for the operator at a position below the flooring material 212 thereof. The double sheet 202 is composed of an upper filtration sheet 220 and a lower water collecting sheet 222, which are arranged so as to overlap each other in a plan view.

<Filtration sheet>

The filtration sheet 220 is configured to receive the wastewater, filter the wastewater, and capture and recover a coating film piece as a solid substance from the wastewater. The filtration sheet 220 is a flexible mesh sheet, and is suspended in a horizontally stretched and unfolded state by a plurality of handrails selected from the plurality of handrails. The filtration sheet 220 captures a part of the coating film piece from the received wastewater by the mesh of the mesh sheet.

Specifically, from the mesh of the filtration sheet 220, the washing water (fresh water) of the wastewater and the plurality of coating film pieces and debris first mixed in the wastewater are smaller in size than the mesh. Leaks out.

The filtration by the filtration sheet 220 corresponds to the process called "first filtration" in the process diagram shown in FIG. Hazardous substances contained in the coating film pieces and debris that have passed through the filtration sheet 220 are captured and removed by the "second filtration" and the "third filtration" in the process chart.

<Water collection sheet>

The water collecting sheet 222 is configured to receive the wastewater after filtration by the filtration sheet 220 from the filtration sheet 220 and guide the filtered wastewater to the wastewater outlet 224 by utilizing its own weight. The water collecting sheet 222 is mainly composed of a flexible meshless sheet, and is suspended in a horizontally stretched and unfolded state by a plurality of handrails selected from the plurality of handrails. NS.

The catchment sheet 222 generally forms a four-sided shape in the unfolded state, and is connected to the selected plurality of handrails 215 (see FIG. 17B) on two or four sides thereof. The connection is performed so that no gap is generated between each handrail 215 and the corresponding side of the water collecting sheet 222, whereby the wastewater is prevented from leaking from the gap. ..

As shown in FIG. 17B, in one example, a flexible elongated extension portion 223 is joined to the corresponding side of the water collecting sheet 222 in a posture extending parallel to the side (for example,). , Sewn). The extension 223 is wound around and connected to the corresponding handrail 215, whereby the catchment sheet 222 is suspended (suspended) by a scaffold 210.

The water collecting sheet 222 has a bottom portion 222b lower than its peripheral portion 222a in the central portion thereof, and has a mortar-shaped shape as a whole. When the water collecting sheet 222 receives the wastewater from the filtration sheet 220 at the peripheral portion 222a, the wastewater descends along the peripheral portion 222a due to its own weight and eventually joins at the bottom portion 222b. A wastewater outlet 224 for sending wastewater downstream is installed at the bottom 222b.

<Coagulation tank and filtration basin>

FIG. 18 is a perspective view showing an example of the remaining portion of the wastewater treatment unit 200 shown in FIG.

The wastewater outlet 224 of the water collecting sheet 220 is airtightly connected to the wastewater outlet 224 in a state where the upper end of the connecting pipe 230 extending in the generally vertical direction is fluidly communicated with the wastewater outlet 224. The lower end of the connecting pipe 230 is a drain pipe 232 that transports the waste water to a predetermined place located at the lower part of the scaffold 210 or away from the scaffold 210 and extends two-dimensionally or three-dimensionally. It is airtightly connected in a fluid communication state.

The drain pipe 232 has an outlet portion 234 in a vertically extending posture, for example. The wastewater discharged from the outlet portion 234 is sent into the coagulation tank 240. The coagulation tank 240 collects and stores the filtered wastewater discharged from the wastewater outlet 224.

In the coagulation tank 240, coagulant those containing hazardous substances to a waste water contained therein, at least one of the adsorbent such as heavy metal insoluble agent and active carbon powder is added, whereby , A predetermined harmful substance in the wastewater is agglomerated. As a result, agglomerates (flocks) are generated in the wastewater.

Here, the "aggregating agent" is added to agglomerate a plurality of particles of a harmful substance selected in advance by charge neutralization.

Further, the "heavy metal insolubilizer", for example, solidifies and insolubilizes the heavy metal in the coating piece in the wastewater in the original position, thereby suppressing the elution of the heavy metal into the washing water as a solvent in the wastewater. As a result, if the coating piece is captured, the heavy metal is added together with it to promote the capture without leakage.

Further, "adsorbent such as activated carbon" is added to adsorb and capture heavy metal ions in wastewater by ion exchange. It is effective to configure the activated carbon as a plurality of particles or as a filter.

Regardless of which of these three types of heavy metal scavengers is used, heavy metals or objects containing heavy metals are trapped in the wastewater to form aggregates. In addition, two or more of these three types of heavy metal scavengers may be used in combination in the same wastewater. It is expected that the combined use will improve the capture effect and widen the types of substances to be captured.

Further, in the coagulation tank 240, the wastewater and the coagulant are agitated, whereby the amount of agglomerates as a precipitate increases. In the coagulation tank 240, the supernatant liquid and the precipitate are separated into upper and lower parts due to the difference in specific densities of the two.

Here, "aggregation, stirring and separation" corresponds to the process of "aggregation, stirring and separation" in the process diagram shown in FIG.

Further, in the coagulation tank 240, the wastewater is filtered by a filtration unit (not shown), whereby the sediment is trapped in the wastewater, and as a result, only the supernatant liquid is discharged from the coagulation tank 240. ..

Here, "filtration" corresponds to a process called "second filtration" in the process diagram shown in FIG.

The filtered wastewater (supernatant, treated water, etc.) discharged from the coagulation tank 240 is sent into the filtration basin 242. The filter basin 242 further filters the wastewater discharged from the coagulation tank 240 to separate the wastewater into a harmful substance as a solid substance and a filtered wastewater from which the harmful substance has been removed.

Here, "filtration" corresponds to a process called "third filtration" in the process diagram shown in FIG.

FIG. 19 shows an example of the wastewater treatment shown in FIG. 9, which is described above, in a process diagram.

Of the wastewater treatments, steps S31-34 have been described above.

Then, in step S35, the wastewater in the filter basin 242 is separated into a harmful substance (sludge (precipitate)) as a solid substance and a wastewater (liquid) after filtration from which the harmful substance has been removed.

Subsequently, in step S36, the above-mentioned wastewater (liquid) after filtration is drained as detoxified, or in step S37, the detoxified wastewater is reused as new wash water. To do this, a submersible pump (eg, installed in tank 125 (see FIG. 10)) (not shown) is used to recirculate into tank 125.

Here, the submersible pump corresponds to a reusing means for reusing the detoxified wastewater discharged from the filtration basin 242 (an example of the "filtration unit") as new washing water.

The sludge is packed in the filtration bag 244. The filter bag 244 is a flexible bag having a filtering function (for example, a bag made of sewn mesh sheets), which is configured to have a size that can be easily carried by an operator, for example. ..

Subsequently, in step S38, the sludge is drained using the filter bag 244, whereby the sludge passes through the mesh of the filter bag 244 and the moisture remaining in the filter bag 244 without passing through the sludge. It is separated into flocs.

The water may be treated in the same manner as the water that has passed through the filter basin 242, but may be drained as detoxified wastewater.

On the other hand, the wet flocs are dried together with the filtration bag 244 (leave to dry naturally, or forcibly dried using a dryer or a heater in a drying chamber) to dehydrate the wet flocs, whereby the wet flocs become dry flocs. It is altered, resulting in a reduction in the amount of flocs remaining in the filter bag 244. At this time, dry flocs remain in the filtration bag 244.

Then, in step S39, the dried flocs are removed from the filter bag 244 and the dried flocs are disposed of as hazardous waste at a specific location.

Here, the filter bag 244 (another example of the "filter section") and the dryer or heater are both wet flocs that do not pass through the filter bag 244 and remain there and contain harmful substances. It corresponds to a weight reduction means of dehydrating and thereby reducing the amount of toxic waste to be discarded.

Here, "dehydration" is performed using the dryer or heater, but may be performed in place of or in addition to, for example, a centrifuge.

In addition, in the present embodiment, an ion exchange fiber layer or an ion exchange resin layer is used as an optional element. When the filtered wastewater (in the process diagram shown in FIG. 19, the wastewater after the second filtration and / or the wastewater after the third filtration) passes through the layer, the layer passes heavy metal ions in the wastewater. Capture and collect.

The present inventor uses a prototype of the wastewater treatment unit 200 to confirm the effect of the wastewater treatment unit 200 when the physical removal by the high-pressure washing this time is performed after the chemical removal of the coating film using the release agent. Was tested.

As a result of the test, the present inventor confirmed the following multiple effects.

1. 1. It became easier to collect the coating film pieces (peeling residue) generated from the structure 12 during high-pressure cleaning and to collect the coating film pieces at a specific storage location, and the man-hours required for the operator were reduced.

2. Since the solid component is recovered and captured from the wastewater by a plurality of stepwise filtrations, the degree of detoxification of the wastewater is improved.

3. 3. Since the wastewater treatment unit 200 was installed at the site 210 before the release agent was applied to the structure 12, the release agent was applied on the surface of the structure 12 and then exposed to wind and rain. Even if the release agent flowing down from the structure 12, it was captured by the wastewater treatment unit 200, thereby preventing the release agent from flowing out of the wastewater treatment unit 200.

In addition, the above-mentioned wastewater treatment unit 200 may be adopted in combination with a cleaning gun different from the cleaning gun 110, in combination with a completely different cleaning gun, or independently. Is possible.

<Another coating film peeling method>

FIG. 20 shows another example of the coating film peeling method shown in FIG. 9 in a process diagram.

In the coating film peeling method shown in this process diagram, unlike the method shown in FIG. 9, high-pressure cleaning is present in each of the two steps.

These steps are preliminary high pressure cleaning and production (full-scale, regular) high pressure cleaning, and the same wet peeling as shown in FIG. 9 is performed between these two types of high pressure cleaning. The actual high-pressure cleaning is carried out in the same manner as the high-pressure cleaning shown in FIG. After this production high pressure cleaning, the same wastewater treatment as shown in FIG. 9 is carried out.

Preliminary high pressure cleaning is performed on the existing coating film 14 before the release agent is applied onto the existing coating film 14. In this preliminary high-pressure cleaning, cleaning water is sprayed toward the existing coating film 14 using a cleaning gun 110, thereby cleaning the surface of the existing coating film 14 to which the release agent is to be applied. At the same time, in the existing coating film 14, the portion of the existing coating film 14 that is raised from the surface of the structure 12 is peeled off and removed before the application of the release agent.

As an effect of this pre-cleaning step, the amount and area of the existing coating film 14 adhering to the surface of the structure 12 prior to the application of the release agent are reduced as compared with the case where the pre-high pressure cleaning is not performed. After the implementation, the area of the surface of the structure 12 to which the release agent should be applied decreases, and thus the amount of the release agent required for the structure 12 decreases.

As a further effect of this pre-cleaning step, when cleaning water enters between a portion of the existing coating film 14 that is about to be peeled off from the substrate of the structure 12 and the substrate, a release agent is subsequently applied to that portion. Then, the release agent easily adheres to the back surface of the existing coating film 14 that is about to be peeled off. As a result, the peeling of the existing coating film 14 by the release agent is promoted, and the effect of the release agent is increased.

This effect is achieved by the cleaning gun 110 high-pressure spraying the cleaning water onto the structure 12 at a high temperature (for example, above 60 ° C., above 80 ° C., above 90 ° C., or reaching the boiling point). If steam is generated from the sprayed wash water, it will be promoted. Specifically, since the gas called steam has a higher followability to the mating member than the liquid, it enters between the part of the existing coating film 14 that is peeling off from the base material of the structure 12 and the base material. And it becomes easy to penetrate.

As an example of the set value of the injection pressure of the cleaning gun 110, the first injection pressure in the preliminary high-pressure cleaning is set to be lower than the second injection pressure in the actual high-pressure cleaning. It can be set to be less than about 50%, less than about 60%, less than about 70%, less than about 80% or less than about 90% of the second injection pressure.

Although some of the exemplary embodiments of the present invention have been described in detail with reference to the drawings, these are examples, and those skilled in the art, including the embodiments described in the [Summary of Invention] column, are described above. It is possible to carry out the present invention in other forms with various modifications and improvements based on knowledge.

Claims (5)

A high-pressure cleaning system for removing a coating film that removes an existing coating film from the surface of a structure by injecting cleaning water at high pressure to clean the surface of the structure.
It includes a wastewater treatment unit that treats the washing water sprayed at high pressure as wastewater containing harmful substances.
The wastewater treatment unit is
A coagulation tank in which a predetermined harmful substance in the wastewater is agglomerated by adding at least one of an adsorbent such as a coagulant, a heavy metal insolubilizer and an activated carbon powder to the wastewater.
High pressure for removing coating film including a filter unit that separates the wastewater into wastewater as a solid substance and filtered wastewater from which the harmful substances have been removed by filtering the wastewater in the coagulation tank. Cleaning system. The wastewater treatment unit further includes an ion exchange fiber layer or an ion exchange resin layer, which captures and recovers heavy metal ions in the wastewater when the filtered wastewater passes through the layer. The high-pressure cleaning system for removing a coating film according to 1. The wastewater treatment unit further
Reuse means for reusing detoxified wastewater that has passed through the filtration section and discharged from it as new washing water.
A claim including a weight-reducing means for dehydrating wet flocs that do not pass through the filtration section and remain there and contain the harmful substances, thereby reducing the amount of harmful substance waste to be discarded. The high-pressure cleaning system for removing a coating film according to 1 or 2. A high-pressure cleaning method for removing a coating film that removes an existing coating film from the surface of a structure by injecting cleaning water at a high pressure to clean the surface of the structure.
When the washing water jetted at high pressure collides with the structure, the washing water as a liquid component and the coating piece as a solid component, which is a coating piece, are physically collided with the washing water from the surface of the structure. Includes a wastewater treatment step to treat the wastewater produced as a mixture with the stripped and removed material.
The wastewater treatment process is
At least one of an adsorbent such as a flocculant, a heavy metal insolubilizer and an activated carbon powder is added to the wastewater recovered at the high-pressure washing site related to the structure, whereby the wastewater is present in the wastewater. Aggregation process that aggregates harmful substances and
A high-pressure cleaning method for removing a coating film, which comprises a separation step of separating and recovering the aggregated harmful substances from the wastewater by filtering the wastewater to which the coagulant is added. The wastewater treatment step further
At the work site related to the structure, the component of the wastewater after filtration is analyzed by using an analysis kit, and the component of the wastewater is a predetermined wastewater standard, and the standard regarding the transparency of the wastewater after filtration is set. An analysis process that determines whether or not to satisfy what you have,
When it is determined that the components of the wastewater satisfy the wastewater standard, the wastewater / reuse step of draining the wastewater or reusing it for the next high-pressure washing is performed.
The coating film removal according to claim 4, wherein when it is determined that the component of the wastewater does not meet the wastewater standard, the wastewater is subjected to a repetitive step of repeating the aggregation step, the separation step and the analysis step. For high pressure cleaning method.

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