WO2023008868A1

WO2023008868A1 - Safety valve for cryogenic liquefied gas

Info

Publication number: WO2023008868A1
Application number: PCT/KR2022/010935
Authority: WO
Inventors: 이덕재
Original assignee: (주)수림테크
Priority date: 2021-07-26
Filing date: 2022-07-26
Publication date: 2023-02-02
Also published as: KR20230016726A; KR102520465B1

Abstract

Disclosed is a safety valve for cryogenic liquefied gas, the safety valve comprising: a hollow upper body that has an outlet formed on a side portion thereof; a lower body which is coupled to the lower portion of the upper body, has an inlet that passes vertically through the center, and has a seating surface formed on the upper surface; a valve bonnet fixed to the upper side of the upper body; a return spring inserted into the valve bonnet; a valve stem which passes through a central portion of the return spring and is embedded in the valve bonnet; a stem guide which is embedded in the center of the upper portion of the valve bonnet and supports the valve stem; a pair of spring caps which are mounted to the upper and lower ends of the return spring so as to prevent the return spring from separating from the valve stem; and a valve disc which is brought into close contact with or separated from the seating surface by the lifting/lowering action of the valve stem inside the upper body, thereby opening and closing the inlet of the lower body.

Description

Safety valve for cryogenic liquefied gas

The present invention relates to a safety valve for preventing the pressure of cryogenic liquefied gas from rising above a certain pressure, and more particularly, a spring-type safety valve for cryogenic liquefied gas that operates normally within a predetermined pressure range even under conditions of cryogenic and high pressure. It's about valves.

In general, cryogenic liquefied gases such as liquefied hydrogen, liquefied natural gas (LNG), and liquefied nitrogen (LN2) (hereinafter collectively referred to as 'liquefied gas') are liquefied at cryogenic temperatures (about -163 ° C or less). It is stored and transported in a liquid state, vaporized through a predetermined vaporization process, and then supplied as a gaseous gas (fuel, etc.).

For example, liquid hydrogen is stored in an insulated and pressure-resistant cryogenic tank at a cryogenic temperature of -253 ° C or lower and liquefied natural gas at -165 ° C or lower.

On the other hand, when the pressure in a tank or pipe exceeds a certain range or reaches a predetermined set pressure, the safety valve automatically operates and emits gas or steam to limit the rise in pressure to prevent damage to equipment, facilities, or pipes. It is a device.

These types of safety valves can be roughly divided into spring loaded type and lever type according to the operation method.

In particular, the spring-type safety valve is closed by compressing the valve seat with the force of a spring, and then opens when the gas or vapor pressure is greater than the force of the spring to maintain safety by allowing gas or vapor to escape. can be changed, and the operation is reliable, so it is most often used as a safety valve.

However, when the spring-type safety valve is applied to the control of cryogenic liquefied gas, the spring is rapidly cooled in the process of discharging the cryogenic liquefied gas, and as a result, the tension of the spring is changed, causing malfunction or failure.

In other words, if the tension of the spring is weakened due to the influence of the temperature of the cryogenic liquefied gas, even if the ejection pressure of the liquefied gas is lowered below the set value or within the error range, the cut-off function does not operate properly, and the liquefied gas is unnecessarily released into the atmosphere, resulting in air pollution. Of course, there are problems of increasing economic loss and fire risk.

Therefore, there is a demand for a spring-type safety valve that can operate normally and safely without changing the tension of the spring even under conditions of ultra-low temperature and high pressure.

The background art or prior art described above herein is information possessed by the present inventor or acquired in the process of deriving the present invention, and is only intended to help understand the technical significance of the present invention, prior to the filing of the present invention, the technology to which this invention belongs It should be noted that it does not mean widely known technologies in the field.

(Patent Document 1) KR Patent Publication 10-2020-0086048 A (2020.07.16)

(Patent Document 2) KR Patent Registration 10-1388510 B1 (2014.04.17)

(Patent Document 3) KR Patent Registration 10-1147815 B1 (2012.05.14)

Therefore, the present inventor comprehensively considers the above-mentioned matters and at the same time minimizes the change in tension of the return spring due to cryogenic liquefied gas in order to solve the technical limitations and problems of the existing spring-type safety valve technology. In order to develop a spring-type safety valve for cryogenic liquefied gas with a new structure that can promote the effect of stably maintaining the conditions for normal operation in .

Therefore, the technical problem and object to be solved by the present invention is to provide a safety valve for cryogenic liquefied gas that can minimize the effect of temperature and malfunction.

Here, the technical problems and objects to be solved by the present invention are not limited to the technical problems and objects mentioned above, and other technical problems and objects that are not mentioned are the general knowledge in the technical field to which the present invention belongs from the description below. Those who have it will be able to clearly understand.

Specific means according to an aspect of the present invention for effectively achieving a specific technical purpose while embodying a new idea for solving the technical problem of the present invention as described above is a hollow upper body with a discharge port formed on the side. , A low body coupled to the lower part of the upper body, having an inlet opening vertically in the center, and having a seating surface formed on the upper surface, a valve bonnet fixed to the upper side of the upper body, and a return spring inserted inside the valve bonnet A valve stem embedded in the valve bonnet passing through a central portion of the return spring, a stem guide embedded in the upper center of the valve bonnet to support the valve stem, and the return spring preventing the return spring from departing from the valve stem. A pair of spring caps mounted on both upper and lower ends of the spring and a valve disk that is in close contact with or separated from the seating surface by the lifting action of the valve stem inside the upper body to open and close the inlet of the lower body, the valve The stem, while the upper part is supported by the stem guide, passes through the middle part of the return spring and the spring caps, and the rod embedded in the upper part of the valve bonnet, the spindle whose lower part is inserted in the center of the valve disc, and the valve bonnet. Connecting and fixing between the rod and the spindle while being embedded in the lower part of, and the cold heat (cryogenic cold air) of the liquefied gas introduced through the inlet of the lower body and discharged to the outlet of the upper body is transferred to the return spring Suggests a safety valve for cryogenic liquefied gas, characterized in that employed including a blocking neck to block.

Accordingly, the present invention can operate normally and safely within a predetermined pressure range by minimizing the tension change of the return spring even under conditions of ultra-low temperature and high pressure.

In addition, in a preferred embodiment of the present invention, the blocking neck is formed of one of engineering plastics and glass fiber reinforced plastics having low thermal conductivity, thereby more effectively blocking the cold heat transmitted to the return spring, thereby reducing the tension or tension of the return spring. Pressure fluctuations can be prevented.

In addition, in a preferred embodiment of the present invention, a barrier for blocking cold heat (cryogenic cold air) of liquefied gas from being conducted to the return spring by expanding a contact area with external air on the lower outer circumference of the valve bonnet By forming at least one or more, it is possible to effectively reduce the occurrence of abnormalities or malfunctions.

According to the technical idea and embodiment of the present invention, on which a unique solution is based to solve the above technical problem, when the pressure rises above the set pressure by installing in a tank or pipe system, liquefied gas is discharged to the outside. In this process, it is possible to effectively block the cold heat (ultra-low temperature cold air) of the liquefied gas from being transferred to the return spring.

Therefore, it can operate normally and safely within a predetermined pressure range by minimizing the tension change of the return spring even under conditions of ultra-low temperature and high pressure.

Here, the effects of the present invention are not limited to the effects mentioned above, and other effects not mentioned will be clearly understood by those skilled in the art from the description of the claims.

1 is a front view showing a safety valve for cryogenic liquefied gas according to an embodiment of the present invention.

FIG. 2 is a partial cross-sectional view showing a cut plane from A to A' in FIG. 1 .

[Description of code]

10: upper body 11: outlet

20: low body 21: inlet

22: seating surface 30: valve bonnet

31: barrier 40: return spring

50: valve stem 51: rod

52: spindle 53: blocking neck

54: adjustment screw 60: stem guide

70: spring cap 80: valve disc

Hereinafter, embodiments according to the present invention will be described in more detail with reference to the accompanying drawings.

Prior to this, the terms to be described below are defined in consideration of functions in the present invention, which specifies that they should be interpreted as concepts consistent with the technical spirit of the present invention and meanings commonly used or commonly recognized in the art.

In addition, if it is determined that a detailed description of a known function or configuration related to the present invention may obscure the gist of the present invention, the detailed description will be omitted.

The accompanying drawings are partially exaggerated or simplified for explanation of the configuration and operation of the technology and convenience and clarity of understanding, and it is revealed that each component does not exactly match the actual size and shape.

In addition, in this specification, the term and / or is meant to include a combination of a plurality of related items described or any item among a plurality of related items described, and when a part includes a certain component, this is particularly the opposite description. As long as there is no , it means that other components can be included more than not excluding other components.

That is, terms such as 'include', 'include', or 'have' mean that there is a feature, number, step, operation, component, part, or combination thereof described in this specification, but one or It should be understood that this does not preclude the possibility of the presence or addition of more other features or numbers, step-action components, parts, or combinations thereof.

In addition, terms such as top, bottom, top, bottom, or top, bottom, top, bottom, front and rear, left and right are used for convenience to distinguish the relative positions of each component. For example, an upper part in the drawing may be named or referred to as an upper part, a lower part may be named or referred to as a lower part, a longitudinal direction may be named or referred to as a front-back direction, and a width direction may be named or referred to as a left-right direction.

Also, terms such as first and second may be used to describe various components. That is, terms such as first and second may be used for the purpose of distinguishing only one element from another element. For example, a first component may be referred to as a second component without departing from the scope of the present invention, and the second component may also be referred to as a first component.

1 and 2, the main components constituting the safety valve for cryogenic liquefied gas according to an embodiment of the present invention are an upper body 10, a lower body 20, a valve bonnet 30, a return It includes a spring 40, a valve stem 50, a stem guide 60, a spring cap 70 and a valve disc 80.

The upper body 10 is made of a hollow shape with an empty inside, a discharge port 11 is formed on its side, and the lower part is formed to be coupled to the lower body 20 by screwing or the like.

Here, of course, the outlet 11 of the upper body 10 may be connected to a separate discharge pipe, conduit, or line to communicate with each other.

The low body 20 is coupled to the lower part of the upper body 10 so as to communicate with each other.

In addition, an inlet 21 opened up and down is formed in the center of the raw body 20, and a seating surface 22 is formed on the upper surface so that the valve disc 80 is in close contact with it.

Here, of course, the inlet 21 of the raw body 20 may be connected to a separate inlet pipe, tank, or piping system to communicate with each other.

The valve bonnet 30 has a hollow cylindrical shape and is fixed to the upper side of the upper body 10 .

In addition, at least one barrier 31 is formed on the lower outer circumference of the valve bonnet 30 to block the conduction of the cold heat (cryogenic cold air) of the liquefied gas to the return spring 40 by increasing the contact area with the outside air. .

Here, the valve bonnet 30 is formed by joining several cylinders by welding or the like, so that the thickness can be easily adjusted and the difficulty of processing can be reduced.

The return spring 40 automatically lowers the valve stem 50 within a predetermined pressure range and presses the valve disc 80 against the seating surface 22 to close the inlet 21 of the valve bonnet 30. inserted inside.

Here, as the return spring 40, it is preferable to use a compression coil spring that acts as a force to resist the applied load, but is not limited thereto, and has the same effect as this, that is, the action of resisting the force to compress If you do, you will be free to use anything.

The valve stem 50 passes through the center of the return spring 40 and is embedded in the valve bonnet 30 .

That is, the valve stem 50 is mounted in a state in which the valve disk 80 is pressurized so as to rise vertically according to the pressure change of the liquefied gas in the tank or piping system.

Here, the valve stem 50 includes a rod 51, a spindle 52, and a blocking neck 53.

The rod 51 is formed in a shape having a certain length up and down, and penetrates the middle part of the return spring 40 and the spring caps 70 while the upper part is supported by the stem guide 60, and is attached to the upper part of the valve bonnet 30. It is built in.

Here, the rod 51 determines the position of the valve stem 50 according to the operation of tightening or loosening the adjustment screw 54 screwed to the top of the valve bonnet 30, that is, by applying to the valve disc 80. By adjusting the force (set pressure), the degree of opening and the pressure at which the liquefied gas inside the tank or pipe is ejected to the outside can be controlled or changed.

The lower part of the spindle 52 is inserted into the center of the valve disc 80.

Here, the spindle 52 has a pointed end to concentrate the force applied to the valve disk 80 toward its center.

The blocking neck 53 blocks the cold heat (cryogenic cold air) of the liquefied gas introduced through the inlet 21 and discharged to the outlet 11 from being transferred to the return spring 40 by the rod 51 and the spin 52 ) is built into the lower part of the valve bonnet 30 while connecting and fixing them.

Here, the blocking neck 53 is preferably formed of either engineering plastic or glass fiber reinforced plastic having excellent durability, impact resistance, abrasion resistance, and the like, and low thermal conductivity.

In addition, of course, the length of the blocking neck 53 may be adjusted in consideration of the temperature and operation time of the cryogenic liquefied gas.

In addition, screw holes are formed on the upper and lower surfaces of the blocking neck 53, and threads are formed on the lower end of the rod 51 and the upper end of the spindle 52 to correspond thereto, thereby coupling by screwing and loosening by fastening the nut. It is desirable to avoid

In particular, it is preferable to fix the lower part of the blocking neck 53 and the upper part of the spindle 52 with parallel pins.

The stem guide 60 is embedded in the upper center of the valve bonnet 30 to stabilize and support the elevation of the valve stem 50 .

Here, the stem guide 60 may maintain a coupled state with the valve bonnet 3 by tightening with a nut.

The spring caps 70 are mounted on both upper and lower ends of the return spring 40 to prevent the return spring 40 from being separated from the valve stem 50.

The valve disc 80 is mounted inside the upper body 10 to open and close the inlet 21 while coming into close contact with or separated from the seating surface 22 by the lifting action of the valve stem 50 .

Here, the upper surface of the valve disk 80 is formed in the shape of a groove with a concave middle portion so that the lower part of the spindle 52 is fitted and point-contacted.

In the safety valve for cryogenic liquefied gas according to an embodiment of the present invention configured as above, when the internal pressure of the tank or pipeline is below the set value, the valve disc 80 is pushed up by the tension and pressure action of the return spring 40. It can maintain the closed state stably.

In this state, when the internal pressure of the tank or pipeline changes by more than the set value, the excess pressure of the liquefied gas is transmitted through the inlet 21 of the low body 20, and the force of the return spring 40 pressing the valve disc 80 overcome and push up, that is, the valve stem 50 and the valve disk 80 go up and switch to the open state, in this case, the liquefied gas is ejected to the outside through the outlet 11 of the upper body 10 to the tank or pipe The internal pressure of the back can be lowered.

At this time, since the middle portion of the length of the valve stem 50 is made of a material such as engineering plastic having low thermal conductivity, transfer of cold heat (cryogenic cold air) of the liquefied gas to the return spring 40 can be effectively blocked.

That is, the blocking neck 53 of the valve stem 50 reliably blocks the cold heat (cryogenic cold air) of the liquefied gas from being conducted to the return spring 40 in the process of being discharged, so that the return spring 40 due to the cryogenic cold heat ) can prevent the tension or pressure from decreasing or changing.

Therefore, it is possible to improve safety and reliability by minimizing the change in tension of the return spring 40 due to temperature even under conditions of ultra-low temperature and high pressure, so that it can operate normally and safely within a predetermined pressure range.

On the other hand, the present invention is not limited by the above-described embodiments (embodiment) and the accompanying drawings, and can be variously modified and applied in various ways not illustrated within the scope without departing from the technical spirit of the present invention, as well as each It is clear to those of ordinary skill in the art that the components can be widely applied by substitution of components and changes to other equivalent embodiments.

Therefore, contents related to the modification and application of the technical features of the present invention should be interpreted as being included within the technical spirit and scope of the present invention.

Claims

a hollow upper body 10 having an outlet 11 formed on the side;

a low body 20 coupled to the lower part of the upper body 10, having an inlet 21 open vertically in the center, and a seating surface 22 formed on the upper surface;

a valve bonnet 30 fixed to the upper side of the upper body 10;

a return spring 40 inserted into the valve bonnet 30;

a valve stem 50 passing through a central portion of the return spring 40 and embedded in the valve bonnet 30;

a stem guide 60 built in the upper center of the valve bonnet 30 to support the valve stem 50;

a pair of spring caps 70 mounted on both upper and lower ends of the return spring 40 to prevent the return spring 40 from being separated from the valve stem 50; and

a valve disk 80 that opens and closes the inlet 21 by coming into close contact with or separated from the seating surface 22 by the lifting action of the valve stem 50 inside the upper body 10;

Including, the valve stem 50,

a rod 51 built into the upper portion of the valve bonnet 30 while penetrating the middle portion of the return spring 40 and the spring caps 70 while the upper portion is supported by the stem guide 60;

A spindle 52 having a lower portion inserted into the center of the valve disc 80; and

Connecting and fixing between the rod 51 and the spin 52 while being embedded in the lower part of the valve bonnet 30, the liquefied gas introduced through the inlet 21 and discharged to the outlet 11 a blocking neck 53 that blocks cold heat (cryogenic cold air) from being transferred to the return spring 40;

Characterized in that comprising a, safety valve for cryogenic liquefied gas.
According to claim 1,

The blocking neck 53 is a safety valve for cryogenic liquefied gas, characterized in that formed of any one of low thermal conductivity engineering plastic or glass fiber reinforced plastic.
According to claim 1,

At least one barrier 31 is formed around the lower outer circumference of the valve bonnet 30 to block the conduction of cold heat (cryogenic cold air) of liquefied gas to the return spring 40 by expanding the contact area with external air. Features, a safety valve for cryogenic liquefied gas.