Check valves and cryogenic liquefied gas storage facilities

Abstract

To provide a check valve in which a valve body can be separated from a valve seat by an external operation. [Solution] This is a check valve in which a valve element moves toward and away from a valve seat to open and close a flow path, thereby controlling the flow of fluid flowing in through an inlet and flowing out through an outlet. The check valve comprises a casing extending in an axial direction, a valve stem inserted into the casing and capable of moving up and down by external operation, the valve element provided coaxially with the valve stem and capable of moving relative to the valve stem, an inlet provided below the casing, and a valve seat formed to surround the inlet. The valve element is configured to be able to move toward and away from the valve seat in the vertical direction. The valve stem is inserted into a central recess of the valve element, and has an expanded diameter portion at its tip. When the valve stem is pulled up to a predetermined position or above, the expanded diameter portion is configured to lift the valve element upward.

Description

[Technical field]

[0001] The present disclosure relates to a check valve and a storage facility for cryogenic liquefied gas. [Background technology]

[0002] A check valve that is installed in a pipe through which low-temperature liquefied gas flows is known. For example, Patent Document 1 discloses a globe valve for opening and closing a flow path that is installed in a hydrogen outlet path that outputs hydrogen from a liquefied hydrogen tank. In the flow path opening and closing valve of Patent Document 1, the tip of the valve stem is inserted and fixed into a mounting hole of the valve element, and this mounting hole is connected to the outer circumferential surface by a through hole provided in the side wall of the valve element. This configuration prevents gas from accumulating in the dead space inside the valve.

[0003] Patent Document 2 discloses a check valve used in a cryogenic fluid pump for supplying a fluid such as liquid nitrogen. The check valve in Patent Document 2 is a fluid control valve that allows a fluid to flow in one direction, from below to above. This fluid control valve includes a valve seat formed to surround an inlet, and a valve body configured to be movable toward and away from the valve seat in the vertical direction, and a guide portion is provided in contact with the valve body. The guide portion has a fluid guide surface that guides the fluid flowing in from the inlet in the horizontal direction, and a valve body guide surface on a side surface that guides the valve body in the vertical direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Application Publication No. 7-4965 [Patent Document 2] Patent No. 6370797 Summary of the Invention [Problem to be solved by the invention]

[0005] There is a check valve that switches between a closed state in which the valve body is in close contact with the valve seat and an open state in which the valve body is separated from the valve seat depending on the pressure difference between the primary side and the secondary side of the flow path. On the other hand, a check valve installed in a flow path of a low-temperature fluid such as liquefied hydrogen has an extremely small distance between the parts for the purpose of heat insulation and the like. For this reason, even if a fluid is supplied from the primary side and a pressure difference occurs between the primary side and the secondary side, the valve body does not float and the flow path does not open. In this case, it is desired to forcibly separate the valve body from the valve seat to open the flow path. However, for example, in the check valve of Patent Document 2, the valve body cannot be moved by operating it from the outside. If the valve body can be moved by an external operation, the flow path can be forcibly opened even if the valve body does not move and the flow path does not open for some reason, resulting in a check valve with superior reliability.

[0006] An object of the present disclosure is to provide a check valve in which the valve body can be separated from the valve seat by an external operation. [Means for solving the problem]

[0007] The check valve according to the present disclosure is a check valve in which a valve element moves toward and away from a valve seat to open and close a flow path, thereby controlling the flow of a fluid flowing in from an inlet and flowing out from an outlet. The check valve comprises a casing extending in an axial direction, a valve stem inserted into the casing and capable of moving up and down by external operation, the valve element provided coaxially with the valve stem and capable of moving relative to the valve stem, an inlet provided below the casing, and a valve seat formed to surround the inlet. The valve element is configured to be movable toward and away from the valve seat in the vertical direction. The valve stem is inserted into a central recess of the valve element, and has an enlarged diameter portion at its tip. When the valve stem is raised above a predetermined position, the enlarged diameter portion is configured to lift the valve element upward. Effect of the Invention

[0008] According to the check valve of the present disclosure, the valve body can be separated from the valve seat by an external operation. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a cross-sectional view of a check valve according to an embodiment of the present disclosure. [Diagram 2] FIG. 2 is a partially enlarged cross-sectional view of a check valve according to an embodiment of the present disclosure. [Diagram 3] FIG. 3 is a partially enlarged cross-sectional view of a check valve according to an embodiment of the present disclosure. [Figure 4] FIG. 4 is a partially enlarged cross-sectional view of a check valve according to an embodiment of the present disclosure. [Figure 5A] FIG. 5A is a partially enlarged view of a check valve according to an embodiment of the present disclosure. [Figure 5B] FIG. 5B is a partially enlarged view of the check valve according to the embodiment of the present disclosure. [Figure 6] FIG. 6 is a schematic diagram of a storage facility according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [Outline of the embodiment] First, an overview of the check valve according to the present disclosure will be listed and described.

[0011] The check valve according to the present disclosure is a check valve in which a valve element moves toward and away from a valve seat to open and close a flow path, thereby controlling the flow of a fluid flowing in from an inlet and flowing out from an outlet. The check valve comprises a casing extending in an axial direction, a valve stem inserted into the casing and capable of moving up and down by external operation, the valve element provided coaxially with the valve stem and capable of moving relative to the valve stem, an inlet provided below the casing, and a valve seat formed to surround the inlet. The valve element is configured to be movable toward and away from the valve seat in the vertical direction. The valve stem is inserted into a central recess of the valve element, and has an enlarged diameter portion at its tip. When the valve stem is raised above a predetermined position, the enlarged diameter portion is configured to lift the valve element upward.

[0012] A large number of valves are provided in the pipelines of liquefied gas storage facilities. These valves are often low-temperature valves with long valve stems to reduce heat intrusion from the outside. In particular, in facilities for cryogenic liquefied gas such as liquefied hydrogen, the need for heat insulation is high, and not only the length of the valve stem but also the distance between the valve stem and the valve body and the casing is desired to be small. In addition, in order to save space in the storage facility and to facilitate operation, it is sometimes desired to install valves with long valve stems at an angle. Under such circumstances, it has been found that in a check valve in which the valve body moves in response to the differential pressure between the primary side and the secondary side of the flow path to switch between opening and closing the flow path, a problem occurs in which the valve body does not move in response to the differential pressure. With conventional check valves, even in such cases, it is not possible to force open the flow path by operating the valve body from the outside. In view of this situation, a check valve in which the valve body can be moved by external operation and the flow path can be force-opened when necessary has been considered.

[0013] The check valve according to the present disclosure has an expanded diameter portion at the tip of a valve stem inserted into a central recess formed in the center of the valve body, and is configured so that when the valve stem is raised above a predetermined position, the expanded diameter portion of the valve stem lifts the valve body upward. With this configuration, when necessary, the valve body can be lifted by operating the valve stem, opening the flow path and easily restoring the normal state. With the check valve according to the present disclosure, the flow path can be opened and closed reliably, making it easier to operate the storage facility.

[0014] In the check valve, the central recess may have a first portion that accommodates the expanded diameter portion of the valve stem, and a second portion that is above the first portion and has a smaller diameter than the expanded diameter portion of the valve stem, and when the valve stem is raised to a predetermined position or higher, an upper surface of the expanded diameter portion of the valve stem comes into contact with a lower surface of the valve disc that constitutes the second portion, thereby lifting the valve disc upward. With this configuration, a check valve having the effects according to the present disclosure can be configured while maintaining the functions of conventional check valves without significantly changing the configuration of conventional check valves.

[0015] In the check valve, the valve shaft may have a guide ring that slidably abuts against the inner circumferential surface of the casing, and a shaft portion that is connected to the lower side of the guide ring and has a smaller diameter than the enlarged diameter portion, and the outer circumferential surface of the shaft portion of the valve shaft slidably abuts against an inner circumferential wall that defines the second portion of the central recess. With this configuration, the movement of the valve body is guided by the valve shaft, and the movement of the valve body can be stabilized. In addition, the valve shaft does not come off the valve body.

[0016] The check valve may include a handle for moving the valve stem up and down, and an indicator for indicating the up and down position of the valve stem, located above the casing. The check valve according to the present disclosure functions when the valve stem is located within a predetermined range. The indicator for indicating the position of the valve stem serves as a guide when an operator moves the valve stem up and down by operating the handle. Providing an indicator makes it easier and safer to operate the storage facility.

[0017] The check valve may be a low-temperature check valve having a bellows seal on the upper part of the casing. By combining with the bellows seal, a check valve with no leakage and excellent heat blocking performance can be obtained.

[0018] The storage facility for low-temperature liquefied gas according to the present disclosure includes a low-temperature liquefied gas pipe equipped with the check valve. The check valve may be provided in the pipe so that the axial direction of the check valve is inclined relative to the vertical direction. Since the storage facility according to the present disclosure has a long-axis check valve disposed at an incline, it is space-efficient and has a high degree of freedom in designing the storage facility. In addition, the work of the worker is made easier.

[0019] [Specific example of embodiment] Next, an example of a specific embodiment of the check valve and the storage facility for low-temperature liquefied gas according to the present disclosure will be described with reference to the attached drawings. In the present disclosure, the same or corresponding parts in the drawings are given the same reference symbols, and their description will not be repeated. In the present disclosure, unless otherwise specified, the "axial direction" of the check valve means the direction in which the casing of the check valve extends (see axis α in FIG. 1), and the side of the check valve closer to the handle in the axial direction is referred to as "upper" and the side away from the handle is referred to as "lower". The "vertical direction" is the direction along the axial direction mentioned above. However, these designations are intended for the purpose of explanation in this specification, and the arrangement direction of the check valve in the actual facility is not limited to the vertical direction.

[0020] <Low temperature liquefied gas> In the present disclosure, the cryogenic liquefied gas means a fluid that liquefies at a temperature of 120K (approximately -153°C) or less. Examples of the cryogenic liquefied gas include liquefied natural gas, liquefied oxygen, liquefied nitrogen, liquefied hydrogen, and liquefied helium, but the cryogenic liquefied gas is not limited to these examples. The check valve according to the present disclosure is suitable for use in a pipe that circulates cryogenic liquefied gas among the cryogenic liquefied gases. In the present disclosure, the cryogenic liquefied gas means a fluid that liquefies at a temperature of 20K (approximately -253°C) or less. Examples of the cryogenic liquefied gas include liquefied hydrogen and liquefied helium, but the cryogenic liquefied gas is not limited to these examples.

[0021] <Overall structure of check valve> 1 is a cross-sectional view of a check valve 1, which is an example of a check valve according to the present disclosure. The check valve 1 is a fluid control valve that regulates a fluid to flow only in one direction, from a primary side L1 to a secondary side L2 of a flow path. An S-shaped flow path from an inlet Q1 to an outlet Q2 is formed inside a body 2. A casing 3 is welded to the body 2. The casing 3 is a long cylindrical member extending along an axis α.

[0022] A valve stem 20 is inserted into the casing 3. The valve stem 20 is connected to a handle 61 via a handle shaft 65, and the valve stem 20 moves up and down in response to the operation of rotating the handle 61. A valve element 10 is accommodated inside the body 2. The valve element 10 is provided coaxially with the valve stem 20, and the valve element 10 can move up and down in a direction along the axis α. The valve element 10 has a resin seal ring 18 that serves as a seating portion. The seal ring 18 is provided at a position where it abuts against a valve seat 80 that serves as a seating surface of the inlet Q1. The state where the seal ring 18 abuts against the valve seat 80 is the closed state (the state shown in FIG. 1). In the state shown in FIG. 1, the valve stem 20 is tightened to the lowest position, and the valve element 10 is brought into close contact with the valve seat 80 by the valve stem 20, and the flow path is forcedly closed (continuously closed). The details of the configurations of the valve element 10 and the valve stem 20 will be described later.

[0023] A connector 53 is welded to the top of the casing 3. That is, the body 2, the casing 3, and the connector 53 are welded together to form the valve body 5. A flange portion is formed on the top of the connector 53. The flange portion of the connector 53 is fixed with bolts opposite the bonnet flange 51 via a bellows flange 57. A bellows 55 is provided above the casing 3 and inside the connector 53. The check valve 1 is a bellows seal valve provided with the bellows 55 inside the valve body 5, and has excellent sealing properties and heat insulation properties.

[0024] A handle shaft 65 is inserted inside the bonnet 52 which extends along the axis α. The handle 61 is integrated with a ground cover 62 which covers a gland 66. When the handle 61 moves up and down relative to the bonnet 52 by rotating the handle 61, the ground cover 62 also moves up and down relative to the bonnet 52. An indicator line 63 is provided on the outer peripheral surface of the bonnet 52 along the circumferential direction of the bonnet 52. Also, an indicator line 64 is provided on the outer peripheral surface of the ground cover 62 along the circumferential direction of the ground cover 62. The indicator will be described later.

[0025] <Check valve details> Figures 2 to 4 are all enlarged cross-sectional views of a portion of the check valve 1. Figure 2 shows the flow path in a forcibly closed state, Figure 3 shows the flow path in a forcibly open state, and Figure 4 shows the state in which the check valve is functioning and the flow path is open due to the differential pressure of the fluid. There are no particular limitations on the installation location of the check valve 1, but to explain the case in which the check valve 1 is provided on a supply line for supplying low-temperature liquefied gas, Figure 2 shows when the supply line is not in use (a state in which the supply line is continuously closed), Figure 3 shows when the valve disc is pulled up to forcibly open the flow path, and Figure 4 shows a state in which liquefied hydrogen is flowing through the supply line.

[0026] The configurations of the valve body 10 and the valve shaft 20 will be described with reference to FIG. The valve body 10 includes a guide ring 15, a disk 16, a seal ring 18, and a disk guide 17, which are fixed together and integrated. A central recess C1 that is recessed downward in the axial α direction is formed in the center of the valve body 10. The bottom surface of the valve body 10 is sealed, and the upper portion has an opening that forms the central recess C1. The guide ring 15 is an annular member having an axial through hole in the center. The outer peripheral surface of the guide ring 15 is in slidable contact with the inner peripheral surface of the casing 3. The inner peripheral surface of the guide ring 15 is in slidable contact with the outer peripheral surface of the shaft portion 22 of the valve shaft 20.

[0027] A disk 16 is fixed below the guide ring 15. The disk 16 is a cylindrical member with a bottom. A plurality of through holes 11 are formed in the side wall of the disk 16. Fluid is introduced into a central recess C1 of the valve body 10 through the through holes 11. An inner diameter W1 of the disk 16 is larger than an inner diameter W2 of the guide ring 15. In other words, the central recess C1 of the valve body 10 includes a first portion having a diameter W1 and a second portion having a diameter W2.

[0028] A seal ring 18 is fixed to the outer periphery of the lower end of the disk 16. The seal ring 18 is a seating portion. The seal ring 18 is preferably made of a resin having excellent heat resistance (cold and hot resistance), such as a fluororesin. A disk guide 17 is provided further below the seal ring 18. The outer diameter of the disk guide 17 is slightly smaller than the diameter of the inlet Q1. The disk guide 17 guides the valve body 10 to move up and down along the axis α, and assists in appropriate contact and separation between the seal ring 18 and the valve seat 80.

[0029] The valve shaft 20 includes a guide ring 21, a shaft portion 22, and an enlarged diameter portion 25. The outer peripheral surface of the guide ring 21 is in slidable contact with the inner peripheral surface of the casing 3. The valve shaft 20 moves up and down along the axial direction α of the casing 3 by being guided by the guide ring 21. The shaft portion 22 is provided below the guide ring 21 and is inserted into the central recess C1 of the valve body 10. An enlarged diameter portion 25 having a diameter larger than that of the shaft portion 22 is formed at the tip of the shaft portion 22 (the tip of the valve shaft 20). A specific component configuration of the enlarged diameter portion 25 may be a nut screwed to the tip of the shaft portion 22. The diameter of the shaft portion 22 is approximately equal to the inner diameter W2 of the guide ring 15, and the outer peripheral surface of the shaft portion 22 is in slidable contact with the inner peripheral surface of the guide ring 15. On the other hand, the diameter W3 of the enlarged diameter portion 25 is smaller than the diameter W1 and larger than the diameter W2.

[0030] FIG. 2 shows a state in which the handle 61 is tightened to the fully closed position. The tip of the valve stem 20 is in contact with the bottom surface of the disk 16, and the seal ring 18 is in close contact with the valve seat 80. This state is the fully closed state of the handle 61. In the state shown in FIG. 2, the fluid pressure in the central recess C1 is substantially equal to the fluid pressure at the outlet Q2. Therefore, when the pressure of the secondary side L2 is higher than the pressure of the primary side L1 (for example, when the inlet Q1 pressure + 0.1 MPa < the outlet Q2 pressure), the valve body 10 is pushed downward by the outlet Q2 pressure, and the seal ring 18 is in close contact with the valve seat 80 to close the flow path. When the pressure of the secondary side L2 is higher than the pressure of the primary side L1 by a predetermined value or more, the valve body 10 does not rise even if it is not held down by the valve stem 20, but the flow path can be reliably closed by tightening the handle 61.

[0031] The position of the upper end surface 25t of the enlarged diameter portion 25 in the state shown in Figure 2 is designated as p0. When the handle 61 is turned in the opening direction from this state, the valve shaft 20 rises in response to the operation of the handle, and when the upper end surface 25t of the enlarged diameter portion 25 reaches position p1, the upper end surface 25t comes into contact with the lower surface 15b of the guide ring 15 of the valve body 10.

[0032] 3 shows a state in which the handle 61 is fully open and the valve stem 20 is further raised from position p1 to position p2. At this time, the valve element 10 is held in a raised state by the valve stem 20, and the flow path is forcibly opened. In this way, even if the valve element 10 does not move from the seated position for some reason, the valve element 10 can be lifted by lifting the valve stem 20 above position p1. In other words, the valve element 10 can be lifted by external operation regardless of the pressure or pressure difference between the primary side L1 and secondary side L2.

[0033] In the check valve according to the present disclosure, the movable width of the valve stem by the handle operation (width from position p0 to position p2) is larger than the clearance between the valve stem enlarged diameter portion in the central recess and the valve body (width from position p0 to position p1). This configuration provides the effect that the valve body housed inside the valve body can be lifted by operating the handle.

[0034] FIG. 4 shows a state in which the check valve functions and the valve element 10 floats. At this time, the handle is in the normally open position. The upper end surface 25t of the enlarged diameter portion 25 is slightly lower than the position p1, and the valve element 10 can move up and down according to the fluid pressure. That is, the check valve functions. When the pressure of the primary side L1 is higher than the secondary side L2 pressure (for example, inlet Q1 pressure + 0.1 MPa > outlet Q2 pressure), the valve element 10 floats and the flow path is opened. This is typically the case when liquefied hydrogen is supplied from the primary side L1 to the secondary side L2. When the supply is completed and the secondary side L2 pressure becomes higher than the primary side L1 pressure, the valve element 10 is seated and the flow path is closed. The guide ring 15 and the disk guide 17 act as guides to move the valve element 10 up and down along the axial direction α of the casing 3 and the valve shaft 20.

[0035] Figures 5A and 5B are enlarged views showing the appearance of the vicinity of the handle of the check valve 1. Figure 5A shows a state in which the handle 61 is fully closed, and Figure 5B shows a state in which the handle 61 is fully open. The top of the bonnet 52 is covered with a ground cover 62. An indicator window 67 is formed on the side of the ground cover 62, and the top of the bonnet 52 can be seen through the indicator window 67.

[0036] 5A, when the handle 61 is fully closed (the state in FIG. 2), the indicator line 63 is visible in the indicator window 67. As the handle 61 is rotated in the opening direction, the indicator line 63 moves relatively downward in the indicator window 67. When the handle 61 is fully open (the state in FIG. 3), the indicator line 63 is hidden by the ground cover 62, and the indicator line 63 cannot be seen from the indicator window 67.

[0037] With this configuration, the up and down position of the valve stem 20 can be determined using the indicator line 63 displayed in the indicator window 67 as an index. The check valve functions when the handle 61 is open and the indicator line 63 is located in the indicator window 67. By providing the indicator near the handle, the operator can easily recognize the state of the check valve and operate it correctly.

[0038] <Low temperature liquefied gas storage facilities> The check valve according to the present disclosure may be installed in any location, but is preferably installed in a low-temperature liquefied gas storage facility. In particular, it is preferably installed in a filling line in a storage facility for cryogenic liquefied gas (liquefied hydrogen). Figure 6 is a schematic diagram of a low-temperature liquefied gas storage facility in which a check valve according to the present disclosure is installed.

[0039] 6, the storage facility 100 includes at least a tank 700 for storing low-temperature liquefied gas, a filling line 200 for filling the tank 700 with low-temperature liquefied gas from a transport vehicle such as a tank truck R for transporting the low-temperature liquefied gas, a liquid delivery line 300 for supplying the low-temperature liquefied gas from the tank 700 to a point of use, a pressurization line 400 for supplying the pressurized gas for pressurizing the inside of the tank 700 to the tank 700, an economizer line 500 for mixing the gas in the tank 700 with the liquid delivery line 300 and supplying it to the point of use, and an atmosphere release line 600 for releasing the gas in the tank 700 to the atmosphere. The tank 700 has a highly insulated structure and includes an inner tank 701 for storing the low-temperature liquefied gas, and an outer tank 702 for storing the inner tank 701.

[0040] The check valve 1 according to the present disclosure is installed in the middle of a filling line 200. The filling line 200 is a pipe through which low-temperature liquefied gas flows when the low-temperature liquefied gas is filled into a tank 700 from a tank truck R or the like. The material of the pipe is not particularly limited, and a material conventionally used for this type of pipe, such as stainless steel, can be used. The filling line 200 has a high insulation structure so that the low-temperature liquefied gas can be supplied to the tank 700 in a low-temperature liquid state. As a pipe with a high insulation structure, a vacuum-insulated multi-wall pipe such as a double pipe in which a vacuum insulation layer is formed between an outer pipe and an inner pipe is preferable. The space between the outer pipe and the inner pipe may be filled with a heat insulating material.

[0041] As shown in FIG. 6, in the filling line 200, one end, that is, the first end E1, is connected to the filling hose of the transport vehicle via a pipe joint. The filling line 200 branches into a first filling line 200A and a second filling line 200B. The first filling line 200A is a pipe for filling the inner tank 701 of the tank 700 from the bottom with low-temperature liquefied gas. The second filling line 200B is a pipe for filling the inner tank 701 of the tank 700 from the top with low-temperature liquefied gas. The check valve 1 is installed on the side closer to the first end E1 than the branch point of the first filling line 200A and the second filling line 200B. The check valve 1 regulates the flow direction so that the low-temperature liquefied gas does not flow back from the storage facility 100 toward the transport vehicle.

[0042] There are no particular limitations on the configurations of the liquid delivery line 300, the pressurized line 400, and the atmospheric release line 600, and any conventionally known configurations may be used. Evaporators 800 and 900 are provided midway along the liquid delivery line 300 and the pressurized line 400, respectively.

[0043] The economizer line 500 of the storage facility 100 has a first end E2, which is one end, connected to the upper part of the inner tank 701 of the tank 700. Specifically, the first end E2 of the economizer line 500 is connected to the top of the inner tank 701 and communicates with the upper space (gas phase) G in the inner tank 701. The economizer line 500 has a second end E3, which is the other end opposite to the first end E2, connected to the liquid feed line 300. Specifically, the second end E3 of the economizer line 500 is connected to an upstream part of the liquid feed line 300 close to the inner tank 701 side. The economizer line 500 does not have a portion shared with the atmosphere release line 600, and is a piping independent of the atmosphere release line 600. In addition, the piping configuration is such that the atmosphere release line 600 and the liquid feed line 300 do not communicate with each other. With this configuration, unintended backflow of low-temperature liquefied gas from the liquid feed line 300 to the tank 700 is avoided.

[0044] In the storage facility 100, the check valve 1 may be installed so that its axis α (FIG. 1) is inclined with respect to the vertical direction. Even if the casing of the check valve 1 has a long axis, installing it in an inclined direction saves space and makes it easier for workers to operate it.

[0045] The embodiments disclosed herein are illustrative in all respects and should not be construed as limiting. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the scope and meaning equivalent to the claims. [Explanation of symbols]

[0046] 1 check valve, 2 body, 3 casing, 5 valve body, 10 valve element, 11 through hole, 15 guide ring, 16 disk, 17 disk guide, 18 seal ring, 20 valve stem, 21 guide ring, 22 shaft portion, 25 enlarged portion, 51 bonnet flange, 52 bonnet, 53 connector, 55 bellows, 57 bellows flange, 61 handle, 62 gland cover, 63 indicator line, 64 indicator line, 65 handle shaft, 66 gland, 67 indicator window, 80 valve seat, 100 storage facility, 200 filling line, 300 liquid delivery line, 400 pressurization line, 500 economizer line, 600 atmospheric release line, 700 tank, 701 inner tank, 702 outer tank, 800 evaporator, 900 evaporator.

Claims

1. A check valve in which a valve element moves in response to a pressure difference between a primary side and a secondary side of a flow path, and the flow path is opened and closed by the valve element moving toward and away from a valve seat, A casing extending in an axial direction; a valve stem that is inserted into the casing and can be moved up and down by an external operation; The valve body is provided coaxially with the valve shaft, is not fixed to the valve shaft, and is movable relative to the valve shaft; an inlet provided at a lower portion of the casing; a valve seat formed to surround the inlet; Equipped with The valve body is configured to be movable toward and away from the valve seat in a vertical direction, The valve stem is inserted into a central recess of the valve body, The valve stem has an expanded diameter portion at a tip thereof, When the valve stem is raised to a predetermined position or higher, the expanded diameter portion is configured to lift the valve body upward. non-return valve.

2. A through hole is formed in a side wall of the valve body that defines the central recess of the valve body, and a fluid having a secondary pressure is introduced into the central recess through the through hole. The check valve according to claim 1 .

3. the central recess has a first portion that accommodates the expanded diameter portion of the valve stem, and a second portion that is above the first portion and has a smaller diameter than the expanded diameter portion of the valve stem, When the valve stem is raised to a predetermined position or higher, an upper surface of the expanded diameter portion of the valve stem comes into contact with a lower surface of the valve body constituting the second portion, thereby lifting the valve body upward. The check valve according to claim 1 or 2.

4. The valve shaft has a guide ring that slidably contacts an inner circumferential surface of the casing, and a shaft portion that is connected to a lower portion of the guide ring and has a smaller diameter than the expanded diameter portion, an outer circumferential surface of the shaft portion of the valve shaft and an inner circumferential wall of the second portion of the central recess of the valve body are in slidable contact with each other; The check valve according to claim 1 or 2.

5. Above the casing, A handle for moving the valve stem up and down; and an indicator that indicates the up and down position of the valve stem. The check valve according to claim 1 or 2.

6. A low-temperature check valve having a bellows seal at the top of the casing. The check valve according to claim 1 or 2.

7. A storage facility including a low-temperature liquefied gas pipe having the check valve according to claim 1 or 2, A storage facility for low-temperature liquefied gas, wherein the check valve is provided in the piping such that an axial direction of the check valve is inclined with respect to a vertical direction.

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