KR101523430B1 - A backward flowing interception style dual check valve under super low temperature - Google Patents

Abstract

The present invention relates to a check valve mounted in a cryogenic gas piping system such as an LNG storage facility or a transfer piping system. The check valve can withstand extremely low temperatures, and can open and close the valve quickly and smoothly, To an improved dual check valve.
In the present invention, a main body having a fluid inlet and a fluid outlet formed on both sides and a flow path connecting the fluid inlet and the fluid outlet is formed therein, a retainer formed at an inner central portion of the main body, A main check valve composed of a main disk which linearly moves left and right by an elastic force of the main spring and fluid pressure; And a sub disc sheet mounted on an inner wall of the main disc groove, the sub disc sheet being mounted in a groove recessed in one side of the main disc, a slide plate positioned between one end of the sub disc sheet and the other end of the main spring, A sub-stem coupled to the slide plate and extending to the inside of the main disc groove, a sub-disc formed at the other end of the sub-stem, and a sub spring disposed inside the sub-disc to apply an elastic force to the sub- And a check valve disposed at a downstream side of the check valve.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a double check valve for a cryogenic fluid,

The present invention relates to a check valve mounted in a cryogenic gas piping system such as an LNG storage facility or a transfer piping system. The check valve can withstand extremely low temperatures, and can open and close the valve quickly and smoothly, To an improved dual check valve.

The check valve is a kind of opening / closing device for controlling the flow of the fluid only in one direction and not flowing in the opposite direction.

There are various types of check valves. Depending on the application, there is a difference between the regulated pressure and the material used. The manual check valve maintains a constant flow rate and remains open when there is no back pressure.

The feature of the check valve is that when the fluid acts at a positive pressure, the disk is kept open and the fluid is continuously flowing and closed when the back pressure is applied.

For example, if the set back pressure of the check valve is 30 bar and the back pressure is greater than 30 bar, the valve should be closed. However, the conventional check valve does not close quickly at a back pressure of 30 bar even when the set back pressure is 30 bar, and even if it is 35 bar, it keeps the open state without being closed.

If the valve can not be closed quickly even if the set back pressure is exceeded, the operation fluid leaks undesirably and the valve disc is instantly closed due to excessive pressure, which causes noise or vibration and adversely affects the valve device there is a problem.

Such a check valve operation delay may cause a serious danger to the safety of the apparatus, particularly in the case of a facility for transferring a cryogenic fluid such as an LNG piping facility.

Therefore, it was requested to develop a check valve which can be mounted on a cryogenic fluid transfer piping line, operates accurately even at a fine set pressure, operates smoothly with smooth opening and closing of the valve, and has low vibration and noise.

Patent Publication No. 90-004354 entitled "2-way check valve for automobiles" Patent Publication No. 1995-0002532 "Line check valve" Patent Publication No. 2003-0079821 "Anti-backlash check valve" No. 10-0871878 entitled " Pneumatically Operated Check Valve for Liquefied Gas Storage Tank "

The object of the present invention is to provide a valve disk which is excellent in operability even in a very low temperature environment and operates with precision by detecting a minute pressure difference and particularly operates quickly and smoothly to open and close the valve disk, And to provide a dual check valve having a reverse flow blocking structure of a cryogenic fluid.

In order to solve the above-mentioned technical problems, the present invention provides a fluid supply system, comprising: a main body having a fluid inlet and a fluid outlet formed on both sides thereof and a flow path connecting the fluid inlet and the fluid outlet formed therein; A main spindle mounted inside the retainer, a main disk moving linearly in a lateral direction by an elastic force and a fluid pressure of the main spring, and a first fluid inlet passage formed in the retainer, A main check valve comprising a guide rod formed on the main disk to guide linear movement and a second fluid inflow passage formed on the guide rod; And a sub disc sheet mounted on an inner wall of the main disc groove, the sub disc sheet being mounted in a groove recessed in one side of the main disc, a slide plate positioned between one end of the sub disc sheet and the other end of the main spring, A sub-disc formed on the other end of the sub-stem, the sub-disc having one side portion connected to the slide plate and the other side portion extending to the inside of the main disc groove across the sub-chamber communicating with the second fluid inflow path, And a sub-spring disposed on the inner side of the sub-disc and configured to apply an elastic force to the sub-disc.

In this case, it is preferable that a bar-shaped stem extends in one direction at the center of the plate surface of the main disk, and is installed to pass through the center of the retainer.

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Also, it is preferable that a disk guide of a foam chain using titanium sintering is formed between the inner wall of the main body and the retainer so that the circumferential end of the main disk moves linearly while maintaining contact with one surface of the disk guide.

According to the present invention, it is possible to quickly and accurately perform opening and closing of a valve by detecting a minute pressure difference in the vicinity of a set pressure. Especially, by detecting a minute operating pressure by a plurality of sub check valves mounted inside the main disk of the main valve, So that the operation reliability is excellent and the opening and closing of the valve disc can be performed smoothly and smoothly, thereby minimizing the occurrence of noise or vibration due to sudden shock cutoff of the valve disc.

1 is a sectional view and a side view of an open state of a dual check valve of the present invention.
2 is a sectional view and a side view of a closed state of the dual check valve of the present invention.

Hereinafter, the structure and operation principle of the present invention will be described in detail with reference to the accompanying drawings.

The dual check valve 100 of a cryogenic fluid of the present invention has a fluid inlet 101 and a fluid outlet 102 formed on both sides thereof, A main check valve 110 in which a flow path communicating with the inlet port 101 and the fluid outlet port 102 is formed and a sub check valve 150 formed on the main disk 115 to be described later of the main check valve 110 .

The main check valve 110 includes a main body 111 having a fluid flow path formed therein and a disk guide 112 formed inside the main body 111. The disk guide 112, A main spring 114 attached to the retainer 113 and a main disk 115 supported by the elastic force of the main spring 114. The retainer 113 is formed at the center of the inner main body 111, .

The disk guide 112 is formed as a foam apparatus using titanium sintering to contact the circumferential edge of the main disk 115 and guides the left and right linear motion of the main disk 115.

A retainer 113 is formed on the inner side of the disk guide 112 so as to be integrated with or separated from the main body 111. The retainer 113 is located at the center of the fluid passage in the main body 111 and the main disk 115 is slidably mounted to the right end of the retainer 113.

A retainer chamber 113a which is a hollow space formed between the retainer 113 and the main disk 115 is formed in the retainer 113. A main spring 114 is mounted inside the retainer chamber 113a, do.

A rod-shaped stem 117 is elongated in the left and right direction at the center of the end surface of the main disk 115 and a pair of guide rods 118a and 118b are formed on both sides of the stem 117 .

One end of the stem 117 extends through the central portion of the retainer so as to be exposed to the outside and the pair of guide rods 118a and 118b are in close contact with the inner wall of the retainer 113 chamber 113a, Respectively. In the drawing, reference numeral 119 denotes an O-ring.

As shown in the figure, an elastic protrusion 117a is formed on the outer surface of the stem 117, and a recess groove 113b is formed in an inner wall of the central portion of the retainer 113. [

Therefore, when the main disk 115 linearly moves leftward due to the fluid pressure to open the flow path of the valve, it is preferable that the elastic protrusion 117a is elastically inserted into the recess groove 113b and fixed. Here, the combination of the elastic protrusion 117a and the recessed groove 113b is defined as a press-fit type locking means. In the drawing, reference numeral 116 denotes a main disc sheet.

As shown in the figure, a plurality of sub check valves 150a, 150b, 150c and 150d are mounted on the main disk 115. In the figure, a total of four sub check valves 150 are formed. 1 (a), only one sub-check valve 150 is specifically shown and the remaining sub-check valves are omitted.

As shown in the drawing, the sub check valve 150 is formed inside the groove after being recessed to be recessed rightward from the left end of the main disk 115. The sub-disk sheet 151, 152, a sub-stem 155, a sub spring 153, and a slide plate 154.

The sub disc sheet 151 is fixed to the inner wall of the groove recessed in the main disc 115 and the sub disc 152 has a spherical shape to contact or release the disc sheet 151.

In the spherical sub-disc 152, a rod-shaped sub-stem 155 extending to the left side is formed.

A disk-shaped slide plate 154 is coupled to one end portion (left end in the drawing) of the sub-stem 155, and the other portion extends inward of the main disk groove. The other end of the main spring 114 is attached to the outer surface of the slide plate 154 so that the sub-disk 152 can be linearly moved to the left or right by the elastic force of the main spring 114.

In the drawing, reference numeral 156 denotes a subchamber which is a space part formed inside the sub check valve 150. As shown, the other extended portion of the sub-stem 155 traverses the sub-chamber 156.

A first fluid inflow passage 121a is formed in the retainer 113 of the main body 111 and a guide rod 118a located on the upper portion of the sub check valve 150 corresponds to the first fluid inflow passage 121a. Two fluid inflow channels 121b are formed to communicate with the sub chamber 156 of the sub check valve 150. [

The operation principle of the dual check valve 100 of the present invention having the above structure will be described as follows.

When the pressure of the fluid entering the inlet port 101 is lower than the predetermined pressure, the main disk 115 is kept closed as shown in FIG. 2, and the sub check valve 150 is also kept closed.

That is, in the closed state of the valve, the sub spring 153 having the weaker elastic force than the main spring 114 in a state where the right end of the main spring 114 is in contact with the slide plate 154 of the sub check valve 150, Only the sub-disc 152 is pushed to the left to close the flow path of the sub-check valve 150. At this time, the sub disc 152 comes into contact with the sub disc sheet 151 to be in a seated state.

In this closed state, when the fluid flows into the fluid inlet 101 at a pressure equal to or higher than the set pressure, the main spring 114 compresses to the left and the flow path is opened by the main disk 115.

The elastic protrusion 117a resiliently couples to the recess groove 113b and the first fluid inflow passage 121a and the second fluid inflow passage 121b Are connected to each other as shown in Fig.

The main spring 114 is compressed by the working pressure of the fluid applied to the main disk 115. In this process, the slide plate 154, which is in contact with the one end of the main spring 114, So that the sub disc 152 is linearly moved to the right side and the sub check valve 150 is opened.

In this process, a part of the fluid flowing into the main check valve 110 flows into the sub-chamber 156 through the second fluid inflow passage 121b to form a constant pressure.

An additional compression force is applied to the main spring 114 due to the pressure formed inside the sub-chamber 156 and the main disk 115 is softly and quietly opened without a large impact near the set pressure.

Due to the minute pressure sensing operation of the sub check valve 150, for example, when the valve opening / closing set pressure is 30 bar, even if the fluid flows into the main disk 115 with a pressure slightly exceeding 30 bar, the main disk 115 reacts accurately, It opens up.

On the contrary, when the pressure of the inflow fluid is lower than the set pressure, the main disk 115 is linearly moved to the right by the elastic force of the main spring 114 in the open state of FIG.

Immediately before the main disk 115 returns to its original position and contacts the main disk sheet 116, the slide plate 154 is released from the urging force of the main spring 114 and by the elastic force of the sub spring 153 And moves to the left.

As a result, the sub disc 152 contacts the sub disc sheet 151 and the sub check valve 150 is closed.

In this process, the main disc 115 suddenly operates due to the decrease of the inflow pressure of the fluid, so that the main disc 115 is prevented from being strongly hit against the main disc sheet 116 while the main disc 115 is gradually closed smoothly.

As described above, according to the present invention, the sub-check valve 150, which is integrally formed on the main disk 115, can smoothly and precisely perform the opening and closing operations of the main valve 110.

The present invention relates to a dual check valve mounted on a piping facility or the like in an ultra-low temperature environment and operating accurately and precisely near a set pressure but having a smooth opening and closing operation of the main disk, thereby reducing operating shock, vibration and noise.

Therefore, it is necessary to be applied to the storage facility of the cryogenic fluid such as LNG or the fluid transfer piping system.

100: Dual check valve 110: Main check valve
111: main body 112: disk guide
113: retainer 113a: retainer chamber
114: main spring 115: main disk
116: Main disc sheet 117: Stem
117: elastic protrusions 118a, 118b: guide rod
150: Sub check valve 151: Sub disc sheet
152: Sub-disk 153: Sub spring
154: slide plate 155:
156: sub chamber

Claims (4)

A main body having a fluid inlet and a fluid outlet formed on both sides thereof and a flow path connecting the fluid inlet and the fluid outlet formed therein, a retainer formed at an inner central portion of the main body, a first fluid inlet flow path formed in the retainer, A main spring mounted inside the retainer, a main disk linearly moving left and right by an elastic force and a fluid pressure of the main spring, a guide formed on the main disk in contact with the inner wall of the retainer to guide linear movement of the main disk, A main check valve composed of a rod and a second fluid inflow passage formed in the guide rod; And
A sub disc sheet mounted on an inner wall of the main disc groove, the sub disc sheet being mounted in a groove recessed in one side of the main disc, a slide plate positioned between one end of the sub disc sheet and the other end of the main spring, A sub-disc formed at the other end of the sub-stem, the sub-disc having one side portion coupled to the slide plate and the other side portion extending to the inside of the main disc groove across the sub-chamber communicating with the second fluid inflow passage, A sub-check valve positioned inside the sub-disc and configured to apply an elastic force to the sub-disc;
And a second check valve for preventing reverse flow of the cryogenic fluid. The method according to claim 1,
Wherein a rod-shaped stem extends in one direction at the center of the plate surface of the main disc, and is mounted so as to pass through a center portion of the retainer. delete 3. The method according to claim 1 or 2,
Wherein a disk guide of a foam chain using titanium sintering is formed between the inner wall of the main body and the retainer so that the circumferential end of the main disk moves linearly while maintaining contact with one surface of the disk guide. Reverse check double check valve.

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