Check valve and cryogenic liquefied gas storage facility

Abstract

To provide a check valve capable of separating a valve element from a valve seat by external operation.SOLUTION: In this check valve, a valve element is brought into contact with and separated from a valve seat to open and close a flow passage, and the flow of fluid flowing in from an inflow port and flowing out from an outflow port is controlled. The check valve includes a casing extending in an axial direction, a valve shaft inserted into the casing and capable of moving up and down by an external operation, the valve body provided coaxially with the valve shaft and movable with respect to the valve shaft, 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 a vertical direction. The valve stem is inserted into a central recessed portion of the valve body, and the valve stem has an enlarged diameter portion at a distal end thereof. When the valve stem is pulled up to a predetermined position or more, the enlarged diameter portion lifts the valve body upward.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[0002] Check valves installed in piping through which low-temperature liquefied gas flows are known. For example, Patent Document 1 discloses a globe valve for opening and closing a flow path, which is installed in a hydrogen outlet line that discharges hydrogen from a liquefied hydrogen storage tank. The flow path opening and closing valve of Patent Document 1 has a valve stem with a tip end inserted into a mounting hole in a valve element, which 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 dead space within 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 element 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 element. The guide portion has a fluid guide surface that guides the fluid flowing in from the inlet in the horizontal direction, and a valve element guide surface on its side that guides the valve element 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] Some check valves switch between a closed state, in which the valve disc is in close contact with the valve seat, and an open state, in which the valve disc is separated from the valve seat, depending on the pressure difference between the primary and secondary sides of the flow path. On the other hand, check valves installed in flow paths for cryogenic fluids such as liquefied hydrogen have extremely small spacing between their components for purposes such as thermal isolation. As a result, even when fluid is supplied from the primary side and a pressure difference occurs between the primary and secondary sides, the valve disc may not float, preventing the flow path from opening. In such cases, it is desirable to forcibly separate the valve disc from the valve seat to open the flow path. However, the check valve disclosed in Patent Document 2, for example, does not allow the valve disc to be moved externally. If the valve disc could be moved externally, the flow path could be forcibly opened even when the valve disc remains stuck and the flow path cannot be opened for some reason, resulting in a more reliable check valve.

[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 fluid flowing in through an inlet and out through an outlet. The check valve comprises a casing extending in an axial direction, a valve stem inserted into the casing and movable up and down by external operation, a valve element provided coaxially with the valve stem and movable 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 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 lifts the valve element upward. [Effects 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 explanation 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. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view of a check valve according to an embodiment of the present disclosure. [Figure 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 INVENTION

[0010] [Outline of the embodiment] First, an outline 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 fluid flowing in through an inlet and out through an outlet. The check valve comprises a casing extending in an axial direction, a valve stem inserted into the casing and movable up and down by external operation, a valve element provided coaxially with the valve stem and movable 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 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 lifts the valve element upward.

[0012] Liquefied gas storage facilities often have numerous valves installed in their pipelines. These valves are often cryogenic valves with long valve stems to reduce heat intrusion from the outside. In particular, facilities for cryogenic liquefied gases, such as liquefied hydrogen, require a high degree of thermal isolation, which requires not only a short valve stem length but also a small distance between the valve stem and the valve disc and the casing. Furthermore, to save space and facilitate operation in storage facilities, it is sometimes desirable to install valves with long valve stems at an angle. Under these circumstances, it has been discovered that check valves, which open and close a flow path by moving their valve disc in response to the differential pressure between the primary and secondary sides of the flow path, sometimes fail to move in response to the differential pressure. Conventional check valves, however, cannot forcibly open the flow path by externally operating the valve disc. In light of this situation, a check valve with an externally operated valve disc that can forcibly open the flow path when necessary, has been developed.

[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, if necessary, the valve body can be lifted by operating the valve stem, opening the flow path and easily restoring it to its normal state. The check valve according to the present disclosure reliably opens and closes the flow path, 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 pulled up to a predetermined position or above, the upper surface of the expanded diameter portion of the valve stem comes into contact with the lower surface of the valve disc that constitutes the second portion, thereby lifting the valve disc upward. With this configuration, a check valve that has the effects of the present disclosure can be configured while maintaining the function of conventional check valves without significantly changing the configuration of conventional check valves.

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

[0016] The check valve may include a handle above the casing for moving the valve stem up and down, and an indicator for indicating the up and down position of the valve stem. The check valve according to the present disclosure functions when the valve stem is positioned 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 possible to operate the storage facility more easily and safely.

[0017] The check valve may be a low-temperature check valve provided with a bellows seal on the top of the casing. By combining it with a 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 can be provided in the pipe so that its axial direction is inclined relative to the vertical direction. Since the storage facility according to the present disclosure has a long-axis check valve arranged at an incline, it is space-efficient and has a high degree of freedom in designing the storage facility. It also makes work easier for workers.

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

[0020] <Low temperature liquefied gas> In this disclosure, cryogenic liquefied gas refers to a fluid that liquefies at a temperature of 120 K (approximately -153°C) or lower. Examples of 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 this disclosure is suitable for use in piping that circulates cryogenic liquefied gas, especially cryogenic liquefied gas. In this disclosure, cryogenic liquefied gas refers to a fluid that liquefies at a temperature of 20 K (approximately -253°C) or lower. Examples of 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> FIG. 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 restricts fluid to flow in only one direction, from a primary side L1 to a secondary side L2 of a flow path. An S-shaped flow path is formed inside a body 2, from an inlet Q1 to an outlet Q2. 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 the handle 61 via a handle shaft 65, and moves up and down in response to the operation of rotating the handle 61. A valve element 10 is housed inside the body 2. The valve element 10 is provided coaxially with the valve stem 20 and can move up and down 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 positioned so as to abut against a valve seat 80, which is the seating surface of the inlet Q1. The state in which the seal ring 18 abuts against the valve seat 80 is the closed state (the state shown in Figure 1). In the state shown in Figure 1, the valve stem 20 is screwed all the way down, 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 detailed configurations of the valve element 10 and the valve stem 20 will be described later.

[0023] A connector 53 is welded and fixed to the top of the casing 3. In other words, the body 2, casing 3, and connector 53 are welded together to form a single unit, thereby forming the valve main 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. Bellows 55 are provided above the casing 3 and inside the connector 53. The check valve 1 is a bellows-sealed valve that includes the bellows 55 inside the valve main body 5, and has excellent sealing properties and heat insulation properties.

[0024] A handle shaft 65 is inserted into the bonnet 52, which extends along the axis α. The handle 61 is integrated with a ground cover 62 that 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. Furthermore, 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 indicators 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 forced closed state, Figure 3 shows the flow path in a forced 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 restrictions 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 the state when the supply line is not in use (the supply line is continuously closed), Figure 3 shows the state when the valve disc is pulled up to force open the flow path, and Figure 4 shows the state in which liquefied hydrogen is flowing through the supply line.

[0026] The configurations of the valve body 10 and the valve stem 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 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 top has an opening that forms the central recess C1. The guide ring 15 is an annular member with 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. The inner diameter W1 of the disk 16 is larger than the 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 disc 16. The seal ring 18 is a seating portion. The seal ring 18 is preferably made of a resin with excellent heat resistance (cold and heat resistance), such as a fluororesin. A disc guide 17 is provided further below the seal ring 18. The outer diameter of the disc guide 17 is slightly smaller than the diameter of the inlet Q1. The disc 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 stem 20 includes a guide ring 21, a shaft portion 22, and an expanded 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. Guided by the guide ring 21, the valve stem 20 moves up and down along the axial direction α of the casing 3. The shaft portion 22 is provided below the guide ring 21 and inserted into a central recess C1 of the valve body 10. An expanded 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 stem 20). A specific component configuration of the expanded diameter portion 25 may be a nut threaded onto 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. Meanwhile, the diameter W3 of the expanded diameter portion 25 is smaller than the diameter W1 but larger than the diameter W2.

[0030] FIG. 2 shows the handle 61 in a fully closed position. The tip of the valve stem 20 contacts the bottom surface of the disk 16, forcing the seal ring 18 into tight contact with the valve seat 80. This is the fully closed position of the handle 61. In the position 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 on the secondary side L2 is higher than the pressure on the primary side L1 (for example, when the inlet Q1 pressure + 0.1 MPa < the outlet Q2 pressure), the outlet Q2 pressure presses the valve disc 10 downward, forcing the seal ring 18 into tight contact with the valve seat 80 and closing the flow path. When the pressure on the secondary side L2 is higher than the pressure on the primary side L1 by a predetermined value or more, the valve disc 10 will not rise even if it is not held down by the valve stem 20. However, tightening the handle 61 reliably closes the flow path.

[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 stem 20 rises in response to the handle operation, 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] Figure 3 shows the state in which the handle 61 is fully open and the valve stem 20 is further lifted from position p1 to position p2. At this time, the valve element 10 is held in a lifted 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 its 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 operating the handle (the 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 disc (the width from position p0 to position p1). This configuration has the effect of enabling the valve disc housed inside the valve body to be lifted by operating the handle.

[0034] Figure 4 shows the state in which the check valve is functioning and the valve element 10 is floating. At this time, the handle is in the normally open position. The upper end surface 25t of the expanded diameter portion 25 is slightly below position p1, allowing the valve element 10 to move up and down depending on the fluid pressure. In other words, the check valve is functioning. When the pressure on the primary side L1 is higher than the pressure on the secondary side L2 (for example, inlet Q1 pressure + 0.1 MPa > outlet Q2 pressure), the valve element 10 floats, opening the flow path. This is typically the case when liquefied hydrogen is being supplied from the primary side L1 to the secondary side L2. When the supply ends and the secondary side L2 pressure becomes higher than the primary side L1 pressure, the valve element 10 is seated, closing the flow path. Guided by the guide ring 15 and disc guide 17, the valve element 10 moves up and down along the axial direction α of the casing 3 and valve stem 20.

[0035] 5A and 5B are enlarged views showing the appearance of the area around the handle of the check valve 1. Fig. 5A shows the state in which the handle 61 is fully closed, and Fig. 5B shows the 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 within the indicator window 67. As the handle 61 is rotated in the open direction, the indicator line 63 moves relatively downward within 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 positioned 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 cryogenic liquefied gas, a filling line 200 for filling the tank 700 with the cryogenic liquefied gas from a transport vehicle for transporting the cryogenic liquefied gas, such as a tank truck R, a liquid transfer line 300 for supplying the cryogenic liquefied gas from the tank 700 to a point of use, a pressure line 400 for supplying pressurized gas that pressurizes 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 transfer 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 that stores the cryogenic liquefied gas, and an outer tank 702 that stores the inner tank 701.

[0040] The check valve 1 according to the present disclosure is installed midway along 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 materials conventionally used for this type of pipe, such as stainless steel, can be used. The filling line 200 has a highly insulated structure so that the low-temperature liquefied gas can be supplied to the tank 700 in a low-temperature liquid state. A preferred pipe with a highly insulated structure is a vacuum-insulated multi-wall pipe, such as a double pipe with a vacuum insulation layer formed between an outer pipe and an inner pipe. The space between the outer pipe and the inner pipe may be filled with an insulating material.

[0041] As shown in FIG. 6, one end of the filling line 200, that is, a first end E1, is connected to a filling hose of a 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 below with cryogenic liquefied gas. The second filling line 200B is a pipe for filling the inner tank 701 of the tank 700 from above with cryogenic liquefied gas. The check valve 1 is installed 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 to prevent the cryogenic liquefied gas from flowing back from the storage facility 100 toward the transport vehicle.

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

[0043] The economizer line 500 of the storage facility 100 has one end, a first end E2, 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 within the inner tank 701. The other end of the economizer line 500, a second end E3 opposite the first end E2, is connected to the liquid feed line 300. Specifically, the second end E3 of the economizer line 500 is connected to an upstream portion of the liquid feed line 300 near the inner tank 701. The economizer line 500 does not share a portion with the atmosphere release line 600 and is a piping independent of the atmosphere release line 600. Furthermore, the piping configuration is such that the atmosphere release line 600 and the liquid feed line 300 do not communicate with each other. This configuration prevents unintended backflow of low-temperature liquefied gas from the liquid feed line 300 to the tank 700.

[0044] In the storage facility 100, the check valve 1 may be installed so that its axis α (FIG. 1) is inclined relative 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.

[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 by the above description, and is intended to include all modifications within the meaning and scope of 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 disc, 17 disc guide, 18 seal ring, 20 valve stem, 21 guide ring, 22 stem portion, 25 expansion 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 stem, 66 gland, 67 indicator window, 80 valve seat, 100 storage equipment, 200 filling line, 300 liquid transfer line, 400 pressurization line, 500 economizer line, 600 atmospheric release line, 700 tank, 701 inner vessel, 702 outer vessel, 800 evaporator, 900 evaporator.

Claims

1. A check valve in which a valve element moves toward and away from a valve seat to open and close a flow path and control the flow of a fluid flowing in from an inlet and out from an outlet, a casing extending in an axial direction; a valve stem that is inserted into the casing and that can be moved up and down by external operation; the valve body provided coaxially with the valve shaft and movable relative to the valve shaft; an inlet provided below the casing; a valve seat formed to surround the inlet; Equipped with the valve element is configured to be movable toward and away from the valve seat in a vertical direction, The valve stem is inserted into the 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. 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 .

3. 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 side of the guide ring and has a smaller diameter than the expanded diameter portion, an outer peripheral surface of the stem portion of the valve stem and an inner peripheral 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 .

4. 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 any one of claims 1 to 3.

5. A low-temperature check valve having a bellows seal at the top of the casing. The check valve according to any one of claims 1 to 3.

6. A storage facility including a low-temperature liquefied gas pipe equipped with the check valve according to any one of claims 1 to 3, A storage facility for low-temperature liquefied gas, wherein the check valve is provided in the piping so that the axial direction of the check valve is inclined with respect to the vertical direction.

Images