JP2002219490A - Method for preventing scaling from spa water and apparatus therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent scaling from spa water, not requiring the addition of chemicals like a dispersing agent, nor the virtual change of spa water composition. SOLUTION: An apparatus for preventing scaling from spa water comprising drawing piping to draw spa water from a spa water source and an electric field applying device 6 to apply an electric field to a part of the spa water. A method for preventing scaling from spa water to apply an electric field to the spa water drawn from the spa water source.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for preventing scale deposition from hot spring water extracted from a spring source.

[0002]

2. Description of the Related Art In hot springs where underground hot water is pumped from a spring source, scale disturbance caused by components contained in the hot spring water has become a serious problem. In other words, hot springs are classified according to the components they contain, but among them carbon dioxide springs, bicarbonate springs, and sulfate springs contain abundant minerals. The scale easily precipitates due to the bonding with The deposited scale causes clogging of hot water discharge pipes and valves, so it is necessary to remove it.

Conventionally, the method of removing scale from hot spring water is generally a method using acid washing, but once scale is deposited, it is very difficult to remove the scale. In addition, in acid cleaning, troubles such as environmental pollution due to cleaning waste liquid also occur. For this reason, pipes and valves that are closed due to scaling are sometimes replaced, but replacement requires enormous labor, time, and cost.

[0004] As a solution to the problems of acid washing and parts replacement, a method of preventing the components in hot spring water from being scaled by using a scale dispersant has been implemented. In this case, sodium polyphosphate, sodium polyacrylate, or the like is used as the dispersant. It is considered that there is almost no problem due to the addition of a small amount of any of the chemicals, but the addition of a dispersant may impair the original aroma and efficacy of the hot spring. However, adding a chemical is not a preferred method.

[0005]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned conventional problems, and does not require the addition of a chemical such as a scale dispersant, and therefore does not substantially change the components of the hot spring. It is an object of the present invention to provide a hot spring water-based scale prevention apparatus and a scale prevention method for preventing scale adhesion.

[0006]

According to the present invention, there is provided an apparatus for preventing scale of a hot spring water system, comprising an electric field applying device for applying an electric field to hot spring water taken out of a spring source.

[0007] The method for preventing scale of a hot spring water system of the present invention comprises:
It is characterized in that an electric field application process is performed on the hot spring water taken out of the spring source.

In the present invention, the hot spring water taken out of the spring source is passed through an electric field applying device in which the electrodes are inverted, subjected to an electric field applying process to reduce the tendency to scale, and then circulated to the hot spring water system. This prevents scale deposition.

The electric field application device has a filling layer filled with conductive particles and non-conductive particles in a mixed state between electrodes (anode and cathode). When a voltage is applied between the electrodes, the electric field application device is applied. The conductive particles inside are polarized, and the portion facing the anode is negatively charged, and attracts cations such as Ca and Mg in the hot spring water introduced into the electric field applying device. Conversely, the portion facing the cathode is positively charged and attracts anions such as HCO ₃ and OH in the hot spring water introduced into the electric field application device, and the pH locally increases at this portion. At this time, calcium carbonate and the like are generated in the presence of Ca ions. Here, when the electrode is inverted, the pH drops and calcium carbonate is not generated. Since the reversal interval in the electric field applying device is very short, the generated crystal has a very fine structure without grain growth and is hard to be coarse, and hardly adheres to a pipe or the like. Moreover, even when the scale is attached as a scale, since the scale is an aggregate of fine crystals, the scale can be easily peeled and removed. The electric field-applied water treated in this manner, in which very fine crystals are precipitated, has a remarkably reduced tendency to scale.
The state where the tendency to scale for 4 hours is reduced can be maintained. For this reason, by adding the electric field application treatment water, it is possible to reduce the tendency of the entire system to be scaled and prevent scale deposition.

[0010]

Embodiments of the present invention will be described below in detail with reference to the drawings.

First, an electric field applying device used in the present invention will be described with reference to FIG. FIG. 2 is a schematic sectional view showing the configuration of the electric field applying device 10 suitable for the present invention.

The treatment tank 11 has a cylindrical shape, and is filled with conductive particles 13 and non-conductive particles 14 in a mixed state on a support bed 12 made of large-sized gravel or the like spread on the lower part. Layer 15 is formed. The filling layer 15 is partially omitted in the drawing. A development space 16 is formed above the packed layer 15 in the processing tank 11.

Reference numeral 17 denotes a pipe for introducing the water to be treated into the treatment tank 11. The pipe 17 has a valve V 1, and is provided for expanding the water to be treated introduced from the pipe 17 into the treatment tank 11.
The tip is connected to a sprinkler 18 provided near one side wall of the processing tank 11. The sprinkler 18 has an opening 18a for sprinkling the water to be treated at least at a portion facing the inside of the treatment tank 11, and is water permeable.

Reference numeral 19 denotes a pipe for taking out the electric field applied treatment water, and has a valve V2. In the vicinity of the other half side wall in the treatment tank 11, the electric field application treatment water is collected and the
A water collector 20 is provided so as to face the water sprinkler 18. The water collector 20 is connected to the pipe 19, and at least in a portion facing the inside of the treatment tank 11, for example, water sprinkling. The surface of the container 18 facing the opening 18a is an opening 20a.

In each of the sprinkler 18 and the water collector 20, flat electrodes 21 and 22 are accommodated facing each other. The electrodes 21 and 22 are connected to a power supply device 23 provided outside the processing tank 11. The power supply device 23 is configured to supply a direct current or an alternating current to the electrodes 21 and 22 by changing the polarity.

In the lower part of the treatment tank 11, a water sprinkler / gas sparger 24 having an opening 24a in the support floor 12 below the packed bed 15 is disposed for cleaning the inside of the tank. A cleaning pipe 25 having a valve V3 is connected to the watering / gassing device 24. On the other hand, a cleaning drain / gas discharge pipe 26 having a valve V4 is connected to an upper portion of the processing tank 11.

The electrodes 21 and 22 are made of graphite,
Coal, metal, metal oxide, noble metal, noble metal oxide or an insoluble electrode having a surface coating layer thereof can be used, preferably an electrode of a platinum group element alone or its oxide, or the entire surface of the electrode Alternatively, an electrode coated with a simple substance oxide of a platinum group element at an appropriate ratio may be used.

Examples of the platinum group element include ruthenium, rhodium, palladium, osmium, iridium and platinum, and among them, platinum, ruthenium and iridium are preferable. When the electrode surface is coated with a platinum group element element or oxide, the material of the electrode body is not particularly limited, but is preferably a corrosion-resistant material. Examples of the corrosion-resistant material include titanium, stainless steel, silver, carbon, and aluminum.

The materials of the electrodes 21 and 22 may be the same or different.

The shapes of the electrodes 21 and 22 include a plate shape, a cylindrical shape, a rod shape, a divided shape thereof, a combination thereof, and the like. It is preferable that these electrodes have a long shape and are arranged side by side so as to face each other.

When the electrodes 21 and 22 are provided so as to be in contact with the inner wall of the processing tank 11, the inside of the processing tank 11 can be effectively used, and it is preferable that the electrodes 21 and 22 are arranged apart from the inner wall. Electrode 2
It is preferable that the materials 1 and 22 are dense, but a porous material such as a sintered metal can also be used. In the latter case, the water spraying means and the water collecting means of the electric field applying device are used. Can also be used.

As the conductive particles 13 forming the filling layer 15, it is preferable to use the same insoluble particles as the electrodes. For example, graphite, a metal, a metal oxide, a noble metal, a noble metal oxide, and those having a surface coating layer thereof can be mentioned, and among them, a platinum group element, its oxide, graphite, and a metal oxide are preferable. As a material having a coating layer, particles obtained by coating activated carbon, plastic particles, titanium particles, or the like with an insoluble material such as a platinum group element or an oxide thereof can be used.

On the other hand, the non-conductive particles 14
It is intended to maintain insulation by interposing between them, and is generally used as an insulator glass, ceramic, plastic,
Aluminum silicate, feldspar, quartz, insoluble non-conductive particles such as gravel are preferred, among which glass, ceramic,
Plastics and aluminum silicate are particularly preferred.

The particle shape of the conductive particles 13 and the non-conductive particles 14 is arbitrary, such as spherical or irregular, and the particle size is 0.5 to
70 mm, preferably 20 to 50 mm, specific gravity 1.05
-4, preferably 1.1-3, the sedimentation speed is 1000-3
50,000 cm / sec, preferably 2000 to 200
One having a diameter of 00 cm / sec can be used. The difference between the settling speed of the conductive particles and the non-conductive particles, as described below,
In order to form a uniform filling layer, the thickness is preferably small, for example, 30% or less, preferably 20% or less, particularly preferably 5% or less of the sedimentation velocity of the conductive particles.

The conductive particles 1 forming the filling layer 15
3 and the non-conductive particles 14 are mixed with the non-conductive particles 1
It is sufficient that the conductive particles 4 intervene between the conductive particles 13 so as to prevent the conductive particles 13 from contacting each other. The ratio is preferably 0.5 to 2, more preferably 0.7 to 1.5, of the non-conductive particles with respect to the conductive particles 1 in a ratio.

The conductive particles 13 and the non-conductive particles 1
4 is filled in the treatment tank 11 to form the packed layer 15, and the filling height of the formed packed layer 15 is
It is preferable that the upper and lower portions are approximately the same as or slightly higher than the upper end portions. The filling layer 15 and the electrodes 21 and 22 may be in contact with each other, but are preferably not in contact with each other. In the latter case, the water can be blocked by a liquid-permeable diaphragm. In this case, it is preferable that the water be blocked by the sprinkler 18 and the water collector 20 as shown.

The electric field applying device 1 is configured to form a bipolar electrode having a changed polarity on the conductive particles 13 by applying a current between the electrodes 21 and 22 while changing the polarity. in this case,
If the conductive particles 13 are kept in a non-contact state by the non-conductive particles 14, a bipolar electrode is formed only by applying a current between the electrodes 21 and 22.
The power may be changed from 3 to the circuit connected to the electrodes 21 and 22 while changing the polarity. 2 ways to change polarity
Power may be supplied while inverting DC, or AC may be supplied so that positive and negative voltages are alternately applied to the electrodes or electrode groups. The plurality of electrodes may be divided into three or more groups and the polarity may be changed sequentially. For example, in the case of three groups, the polarity may be changed by supplying a three-phase alternating current.

In the electric field applying process by the electric field applying apparatus 10, the valves V 1 and V 2 are opened and the pipe 1 is opened.
When water to be treated (hot spring water) is passed through the filling layer 15 through the sprinkler 18 and a positive / negative voltage is applied to the electrodes 21 and 22, the conductive particles 13 are interposed by the non-conductive particles 14. Since they are not in contact with each other, the conductive particles 1
3 is polarized in a positive bipolar state on one side and in a negative bipolar state on the other side, forming a bipolar electrode. For example, when a positive charge is applied using the electrode 21 as an anode and a negative electrode is applied using the electrode 22 as a cathode, the side closer to the electrode 21 of the conductive particles 13 becomes negatively charged and becomes a cathode, and is closer to the electrode 22 on the opposite side. The side is positively charged and becomes an anode. For this reason, as described above, the Ca, Mg in the hot spring water is provided on the negatively charged side of the conductive particles.
Cations are attracted, and H
Anions such as CO ₃ and OH are attracted. Then, the scale component reacts by the inversion of the electrode,
Fine field crystals that hardly become coarse and hardly adhere to pipes and the like are precipitated, and water treated with an electric field applied with reduced tendency to scale can be obtained. The obtained electric field applied treated water is collected by the water collector 20 and taken out from the pipe 19.

The voltage applied to the electrodes 21 and 22 of the electric field application device 10 in such an electric field application treatment of the hot spring water may be a value that generates a required amount of hydroxide ions and oxides. Although there is no particular range, it is preferable to be able to change according to the water quality. Further, in order to stably perform the treatment, it is preferable that the voltage can be automatically controlled so that the voltage can be kept constant. The applied voltage is 5 to 40 V, preferably 20 to 30 V, and the current intensity is usually 0.01 to 0.2.
A / dm ² , preferably 0.02 to 0.08 A / d
It is preferable that m ² , the time to maintain the positive or negative polarity, that is, the polarity switching interval (reversal interval) be shorter.

That is, if this time is long, the precipitated crystals are coarsened and the effect of the present invention cannot be obtained, and the hardness component precipitates and adheres to the electrode surface to cause a problem of a decrease in conductivity. . In order to prevent the deposition and adhesion of scale on the electrode surface and to deposit fine crystals, the inversion interval is preferably short, and is preferably 4 minutes or less. By making this time shorter, it is possible to flow into water without growing the scale component on the electrode surface, and it is possible to precipitate ultrafine crystals that are difficult to scale, which is preferable. The reversal interval is particularly preferably from 6 to 60 seconds.

In the electric field applying apparatus 1, when the electric field applying process is continuously performed, the crystals and the suspended matter in the water to be treated are trapped in the packed layer 15, the packed layer 15 is clogged, and it becomes difficult to flow water. In this case, the supply pressure of the water to be treated may increase. In this case, the water supply is stopped and the packed bed 15 is washed. This cleaning may be performed when an increase in the water supply pressure is detected, or may be set so as to perform the cleaning by detecting that a certain operation time or the amount of flowing water has been reached.

In order to perform the cleaning step, first, the valves V1,
V2 is closed to stop the introduction of the water to be treated from the pipe 17,
The valves V3 and V4 are opened, and washing water and / or gas (hereinafter referred to as washing water or the like) is introduced into the lower part of the packed bed 15 from the washing pipe 25 through the sprinkler / sprayer 24. With the introduced washing water or the like, the filling layer 15 is expanded to the expansion space 16 to loosen the conductive particles 13 and the non-conductive particles 14, and the turbidity and crystals trapped by the particles 13 and 14 are washed away. The cleaning water used for cleaning is discharged from the cleaning drain / gas discharge pipe 26.

After the cleaning, when the valve V3 is closed and the introduction of the cleaning water or the like from the pipe 25 is stopped, the developed conductive particles 13 and non-conductive particles 14 settle and the filling layer 15 is formed.

At this time, the conductive particles 13 and the non-conductive particles 1
As described above, if the difference in the sedimentation speed of No. 4 is 30% or less, preferably 20% or less, particularly preferably 5% or less of the sedimentation speed of the conductive particles, the supply of the cleaning water or the like is stopped. The non-conductive particles and the non-conductive particles 14 are uniformly settled in a mixed state, and the filled layer 15 in a substantially uniform dispersed state is formed. Thus, water can be immediately restarted in the filled layer 15. If the mixing is insufficient, a gas or the like may be introduced from the watering / gassing device 24 to perform stirring and mixing.

According to the present invention, when such an electric field applying device is installed in order to perform the electric field applying treatment of hot spring water,
When the electric field applying device breaks down, it can be easily repaired.
Preferably, it is installed on the ground. As a specific treatment method, for example, as shown in FIG. 1A, hot spring water is pumped up from a tip end 2 of a hot water pipe of a hot spring 1 by a pump 3 and supplied to a hot spring bath 8 via a hot water storage tank 4. In the hot spring water system, a circulation line for extracting hot spring water from the hot water storage tank 4 and returning it to the end port 2 of the hot water pipe is provided, a part of the hot spring water in the hot water storage tank 4 is extracted, and an electric field application process is performed by the electric field application device 6. After that, there is a method in which the pressure is increased by the pressure increasing pump 7 and returned to the end port 2 of the hot water pipe. In this way, the hot spring water containing the hardness component is passed through the electric field application device 6 to reduce the tendency to scale, and then returned to the spring source 1, whereby an effect of preventing scale adhesion of the entire hot spring water system can be obtained. .

If the temperature of the hot spring water is excessively high, the electric field applying device 6 may be deteriorated by heat. Therefore, as shown in FIG. After the hot spring water in the tank 4 is cooled by the cooler 5, an electric field is applied by the electric field applying device 6 and returned to the spring source 1. In general, the electric field applying device 6 has heat resistance up to a temperature of about 60 ° C., and therefore, when the temperature of the hot spring water exceeds 60 ° C., the electric field applying treatment is preferably performed by cooling the water to 60 ° C. or less with the cooler 5. .

An appropriate heat exchanger is used for the cooler 5.
The heat obtained by heat exchange with hot spring water can be used for heating other parts.

The proportion of the hot spring water to be subjected to the electric field application is appropriately determined according to the scale of the hot spring source, the composition of the hot spring water, the tendency to scale by the configuration of the piping system, and the like. It is preferably set to about 80%. If the electric field application treatment amount is less than this range, a sufficient scale deposition preventing effect cannot be obtained, and if the amount exceeds this range, no improvement in the scale precipitation preventing effect is observed, and the electric field application treatment cost is unnecessarily high. Only, not preferred.

FIG. 1 illustrates a method of extracting hot spring water from a hot water storage tank, applying an electric field, and then returning the hot spring water to the spring source. However, the present invention is not limited to the illustrated method. The water may be passed through the device, subjected to an electric field application process, and then returned to the spring source. Alternatively, a part of the hot spring water branched from the spring source to the hot water pipe and passed to the hot water pipe may be returned to the hot water pipe after passing the electric field application device through the electric field applying device and applying an electric field. In order to prevent the scale of the entire hot spring water system including the above, it is desirable to return the electric field applied treatment water to the spring source to reduce the tendency of the spring source to scale.

[0040]

The present invention will be described more specifically with reference to the following examples and comparative examples.

Example 1 As shown in FIG. 3, an electric field applying apparatus having the structure shown in FIG. 2 was used.
Then, assembling a test device that resembles the actual hot spring water system,
Was examined for the effect of inhibiting the adhesion of scale. This test equipment is
After storing the spring water in the tank 31 once, it goes through the reservoir 32
To be discharged, and the capacity 10 flowing at 3 t / hr
The hot spring water in the tank 31 of 2.4 t
/ Hr and taken out by the electric field applying device 34 under the following conditions.
After the electric field application process, the mixture was circulated to the tank 31. With test water
Hot spring water has a calcium hardness of about 250mg-Ca
CO₃/ L spa and the temperature was 50 ° C,
It was directly introduced into the electric field applying device 24 and circulated. [Electric field application processing conditions] Voltage 28 V Current intensity 0.06 A / dm²  Polarity reversal time 35 seconds → 45 seconds → 35 seconds → 45 seconds →
…………………… (One electrode is +
Pole → 45 seconds-Pole → 35 seconds + Pole → ……………………
Repeat the other electrode for 35 seconds-pole → 45 seconds + pole →
Repeat for 35 seconds-pole → …………………. )

The thickness of the scale attached to the pipe was measured every 10 days for 50 days so that a part of the pipe from the tank to the pump could be removed. The results are shown in Table 1.

Comparative Example 1 The scale thickness was measured in the same manner as in Example 1 except that the electric field application process was not performed by the electric field application device. The results are shown in Table 1.

[0044]

[Table 1]

As is clear from Table 1, the amount of scale attached was significantly smaller in Example 1 in which the electric field application process was performed than in Comparative Example 1 in which the electric field application process was not performed.
When the scale of the attached hot spring water was examined, the scale of the hot spring water of Example 1 was thinly adhered in the form of a film, whereas the scale of Comparative Example 1 was unevenly deposited. The scale attached to the pipe of Example 1 could be easily peeled off, whereas the scale of Comparative Example 1 was very difficult to peel off.

[0046]

As described in detail above, according to the present invention, there is no need to add chemicals, and therefore, there is little deterioration of the components of the hot spring water, and the scale of the pipes and valves of the hot spring water is attached. Can be effectively prevented, and
Even when the scale is attached, it can be easily peeled and removed.

The present invention can be carried out only by adding an electric field applying device and a circulating water system for hot spring water to the hot spring water system. The electric field applying device can be operated only by supplying power, and requires maintenance. Are very few and can be implemented very easily.

[Brief description of the drawings]

FIG. 1 is a system diagram showing an embodiment of a scale prevention device and a scale prevention method for a hot spring water system of the present invention.

FIG. 2 is a schematic sectional view showing a configuration of an electric field applying device suitable for the present invention.

FIG. 3 is a system diagram showing a test apparatus used in Example 1.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 spring source 2 hot water pipe tip opening 3 pumping pump 4 hot water storage tank 5 cooler 6 electric field applying device 7 boosting pump 8 hot spring bath 10 electric field applying device 11 treatment tank 12 support floor 13 conductive particles 14 non-conductive particles 15 filling layer 16 Deployment space 18 water sprinkler 20 water collector 21,22 electrode 23 power supply device 24 watering / gassing device 31 tank 32 reservoir 33 pump 34 electric field applying device

Claims (3)

[Claims] 1. A hot spring water-based scale prevention device comprising an electric field applying device for applying an electric field to hot spring water taken out of a spring source. 2. The electric field applying device according to claim 1,
A hot spring water-based scale prevention device comprising a bipolar electrode whose anode and cathode are inverted. 3. A method for preventing scale of a hot spring water system, wherein an electric field is applied to hot spring water extracted from a spring source.