A cryogenic shut-off check valve with a pressure-reducing valve disc

Abstract

This invention provides a cryogenic shut-off check valve with a pressure-reducing valve disc. The cryogenic shut-off check valve includes a valve body with an internal cavity; a valve stem inserted into the internal cavity from one end of the valve body and movable along its length; and a valve disc movably disposed within the internal cavity. The valve disc, through the movement of the valve stem along its length, achieves sealing or connection between the inlet and outlet sides of the valve body. One end of the valve disc is used to seal or connect the inlet and outlet sides of the valve body. The valve disc has a movable cavity, with an inner hole at one end of the valve disc communicating with the outside. The valve stem is inserted into the movable cavity through the inner hole. Pressure-reducing holes are provided around the periphery of the inner hole sidewall, so that when the valve stem is raised, the medium flowing into the outlet side through the pressure-reducing holes achieves pressure reduction. The pressure-reducing holes form a pressure-relieving structure, which helps solve the technical problem of existing technologies lacking a mechanism to generate impact loads during startup, leading to water hammer effects.

Description

Technical fields: This invention relates to the field of valve structure technology, and in particular to an ultra-low temperature shut-off check valve with a pressure-reducing valve disc. Background technology: Currently, with the implementation of national energy strategies, green and environmentally friendly clean energy is increasingly favored by the global energy market. Since the liquid volume of natural gas is approximately 1 / 600th of its gaseous volume, its maritime transportation is generally by liquefaction. Therefore, very large cryogenic liquefied natural gas (LNG) carriers have become important and strategic tools in the global natural gas trade. The accompanying marine cryogenic valves are technically challenging, have high quality requirements, are difficult to manufacture, and are difficult to test, placing higher demands on their stability and reliability. Existing check valves for LNG ships experience significant impact loads on the valve disc during rapid closure due to the inertia of the flowing medium. Cryogenic check valves with pressure-reducing orifices on the valve disc body, through the integrated pressure-reducing orifice, greatly eliminate water hammer effects and mechanical vibrations in the pipeline system.

[0001] There is an urgent need for a cryogenic shut-off check valve with a pressure-reducing valve disc, which would help solve the technical problem of the lack of a valve that generates an impact load during startup, leading to water hammer effect. Summary of the Invention: In one embodiment, the present invention provides a cryogenic shut-off check valve with a pressure-reducing valve disc. The pressure-reducing hole forms a structure for releasing pressure, which helps to solve the technical problem that the prior art lacks a mechanism to generate impact loads during startup, leading to water hammer effect.

[0002] The cryogenic shut-off check valve with a pressure-reducing orifice disc includes: A valve body having an internal cavity; A valve stem is inserted into the internal cavity of the valve body from one end and is movable along its length. A valve disc is movably disposed within the internal cavity. The valve disc moves along its length via a valve stem to block or connect the inlet and outlet sides of the valve body. The valve disc has a limiting structure to limit its movement along the valve stem. One end of the valve disc is used to block or connect the inlet and outlet sides of the valve body. The valve disc has a movable cavity with an inner hole at one end that communicates with the outside. The valve stem is inserted into the movable cavity through the inner hole. Pressure-reducing holes are provided around the sidewall of the inner hole so that when the valve stem is raised, the medium flowing into the outlet side through the pressure-reducing holes reduces pressure.

[0003] In one embodiment, when the valve stem is pressed to the bottom, the water inside the movable cavity flows out through the pressure relief hole.

[0004] In one embodiment, a first step is provided in the internal cavity of the valve body so that when the valve stem moves in the lifting direction, the valve disc is limited to the position of the first step.

[0005] In one embodiment, when the valve stem moves in the blocking direction, it presses down on the valve disc to block the communication hole between the water inlet side and the water outlet side, thus limiting the blocking direction.

[0006] In one embodiment, the valve stem and the valve body are connected by a thread to achieve bidirectional movement along the length of the valve stem.

[0007] In one embodiment, the other end of the valve stem extends out of the valve body and is rotated by a handwheel, and then moved in the longitudinal direction by a thread.

[0008] In one embodiment, a packing sleeve is provided at the end of the valve body that is inserted into the valve stem. The lower end face of the packing sleeve and the second step of the valve body are provided with packing and a filling pad. An O-ring is provided between the packing sleeve and the valve body.

[0009] In one embodiment, the valve body has a valve cover through which the valve stem passes, and a threaded sleeve is provided at one end of the valve stem extending outwards from the bottom.

[0010] In one embodiment, the valve stem has a top cover at the top of the valve stem insertion end, the top cover being threaded onto the top of the valve body to press against the packing sleeve, and a hexagonal lock nut is provided at the lower end of the top cover.

[0011] In one embodiment, the valve cover is secured by an internal hexagon head screw. Attached image description: Figure 1 This is a schematic diagram of the cryogenic shut-off check valve structure in one embodiment of the present invention; Figure 2 This is a schematic diagram of the valve disc structure in another embodiment of the present invention. Specific implementation examples: To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0012] Various embodiments and features of this application are described herein with reference to the accompanying drawings.

[0013] These and other features of this application will become apparent from the following description of preferred forms of embodiments given as non-limiting examples, with reference to the accompanying drawings.

[0014] It should also be understood that although this application has been described with reference to some specific examples, those skilled in the art can certainly implement many other equivalent forms of this application, which have the features described in the claims and are therefore all within the scope of protection defined herein.

[0015] The above and other aspects, features and advantages of this application will become more apparent when taken in conjunction with the accompanying drawings and in view of the following detailed description.

[0016] Specific embodiments of this application are described below with reference to the accompanying drawings; however, it should be understood that the claimed embodiments are merely examples of this application, which can be implemented in various ways. Well-known and / or repeated functions and structures are not described in detail to ascertain the true intent based on the user's historical operations, and to avoid unnecessary or redundant details that would obscure this application. Therefore, the specific structural and functional details claimed herein are not intended to be limiting, but merely serve as the basis and representative basis for the claims to teach those skilled in the art to use this application in various ways with substantially any suitable detailed structure.

[0017] This specification may use the phrases “in one embodiment,” “in another embodiment,” “in yet another embodiment,” or “in other embodiments,” all of which may refer to one or more of the same or different embodiments according to this application.

[0018] The purpose of this invention is to provide an ultra-low temperature shut-off check valve with a pressure-reducing valve disc. The pressure-reducing valve disc creates a flow diversion, reducing opening and closing impact and significantly reducing the water hammer effect during valve opening and closing.

[0019] Figure 1 This is a schematic diagram of the cryogenic shut-off check valve structure in one embodiment of the present invention; Figure 2 This is a schematic diagram of the valve disc structure in another embodiment of the present invention. Figures 1 to 2 As shown, in one embodiment, the present invention provides a cryogenic shut-off check valve with a pressure-reducing valve disc, the cryogenic shut-off check valve with a pressure-reducing valve disc comprising: A valve body 1 having an internal cavity 100; A valve stem 5 is inserted into the internal cavity 100 of the valve body 1 from one end and can move along the length direction; A valve disc 2 is movably disposed in an internal cavity 100. The valve disc 2 moves along the length direction via a valve stem 5 to block or connect the inlet side 101 and outlet side 102 of the valve body 1. The valve disc 2 has a limiting structure to limit the movement of the valve disc 2 along the valve stem 5. One end of the valve disc 2 is used to block or connect the inlet side 101 and outlet side 102 of the valve body. The valve disc 2 has a movable cavity 20. An inner hole is provided at one end of the valve disc 2 to connect the movable cavity 20 to the outside. The valve stem 5 is inserted into the movable cavity 20 through the inner hole 201. A pressure reducing hole 202 is provided around the side wall of the inner hole 201 so that when the valve stem 5 is raised, the medium flowing into the outlet side 101 through the pressure reducing hole 202 can achieve pressure reduction.

[0020] During the opening phase, the medium is diverted through the pressure reducing hole 202, reducing the pressure difference on both sides of the valve disc and reducing the impact of opening and closing; during the closing phase, the pressure reducing hole 202 allows a small amount of medium to flow back, gradually balancing the pressure and suppressing the water hammer effect.

[0021] Specifically, when the valve stem 5 is raised, the pressurized water on the inlet side 101 will instantly enter the outlet side 102. At this time, some water will enter the movable chamber 20 from the pressure reducing hole 202 to form a backflow. When the valve stem 5 is lowered to block, it will squeeze out the water in the movable chamber 20 and push against the valve disc 2 again to achieve the blockage.

[0022] In one embodiment, when the valve stem 5 is pressed to the bottom, the water inside the movable cavity 20 flows out through the pressure relief hole 202.

[0023] In one embodiment, a first step 103 is provided in the internal cavity 100 of the valve body 1 so that when the valve rod 5 moves in the lifting direction, the valve disc 2 is limited to the position of the first step 103.

[0024] In one embodiment, when the valve stem 5 moves in the blocking direction, it presses down on the valve disc 2 to block the connecting hole 104 between the water inlet side 101 and the water outlet side 102, thus limiting the blocking direction.

[0025] In one embodiment, the valve stem 5 and the valve body 1 are connected by a thread to achieve bidirectional movement along the length of the valve stem 5.

[0026] In one embodiment, the other end of the valve stem 5 extends out of the valve body 1, and after being rotated by the handwheel 11, it moves in the length direction by the thread.

[0027] In one embodiment, a packing sleeve 8 is provided at the end of the valve body 1 that is inserted into the valve stem 5. A packing 7 and a filling pad 6 are provided between the lower end face of the packing sleeve 8 and the second step 105 of the valve body 1. An O-ring 17 is provided between the packing sleeve 8 and the valve body 1.

[0028] In one embodiment, the valve body 1 has a valve cover 4, which is penetrated by a valve stem 5, and a threaded sleeve 13 is provided at one end of the valve stem 5 extending outward from the bottom.

[0029] In one embodiment, the valve stem 5 has a top cover at one end, which is threaded onto the top of the valve body 1 to press against the packing sleeve 8. A hexagonal locking nut 9 is provided at the lower end of the top cover.

[0030] In one embodiment, the valve cover 4 is secured by an internal hexagon head screw 14.

[0031] Liquefied natural gas (LNG) carriers are specialized vessels designed and built for transporting LNG at ultra-low temperatures of -163°C. Their manufacturing is highly complex, thus requiring sophisticated cryogenic valves. Cryogenic stainless steel shut-off check valves for LNG carriers combine the dual functions of cryogenic fluid shut-off and check valves. This valve structure saves space in ship piping layouts by integrating shut-off and check valve functions, improving fluid performance and reducing flow resistance issues associated with multiple valve structures. Furthermore, the reduced number of valves allows the ship to carry more LNG cargo, improving transportation economics. In contrast, traditional valve discs in cryogenic shut-off check valves for LNG carriers may experience water hammer due to sudden pressure changes when closed, or vibration and noise when partially open. Perforation helps balance pressure and reduce these negative impacts.

[0032] This invention discloses a cryogenic shut-off check valve with a pressure-reducing orifice valve disc. This shut-off check valve combines the functions of a shut-off valve and a check valve, and its structure mainly includes a valve body, valve cover, valve disc, valve stem, sealing elements, and a stuffing box. Its structure is similar to a shut-off valve, but the valve stem and valve disc are not fixedly connected. When the valve stem descends and presses the valve disc tightly against the valve seat, it functions as a shut-off valve; when the valve stem rises, it functions as a check valve. The valve stem passes through the stuffing box, which is filled with sealing packing to prevent media leakage along the valve stem. The valve cover is connected to the valve body by bolts or nuts, pressing the packing tightly within the stuffing box to ensure a tight seal. This invention provides an improved valve disc design for a cryogenic shut-off check valve with a pressure-reducing orifice valve disc. The medium enters through the pressure-reducing orifice for flow diversion, balancing pressure, reducing water hammer, vibration, and noise, while ensuring sealing performance.

[0033] A cryogenic shut-off check valve with a pressure-reducing valve disc, comprising: The pressure relief orifice allows the fluid to gradually release pressure during valve closure, preventing a sharp increase in pressure differential.

[0034] The pressure relief orifice reduces the peak value of the pressure wave by slowing down the pressure release and prolonging the closing time.

[0035] When the valve disc begins to close, the pressure relief orifice allows a small amount of medium to flow back, gradually balancing the pressure and suppressing the water hammer effect.

[0036] The pressure-reducing orifice reduces the flow impact on the valve disc, thereby reducing vibration and noise.

[0037] O-ring 17: Prevents external leakage from the valve and ensures a full seal. Packing compression nut 10: Ensures the packing is always under compression, guaranteeing sealing performance. Hexagonal lock nut 9: Ensures the packing is always under pressure, guaranteeing sealing performance. Packing sleeve 8: Ensures uniform stress on the packing and fully guarantees sealing performance. Packing 7: The specially constructed nickel wire reinforced graphite rings used as end rings have excellent scratch resistance and cleaning function. The high-purity butterfly-shaped graphite used in the middle can achieve high-efficiency sealing under low-premium conditions, fully ensuring the sealing performance of the valve packing.

[0038] Packing pad 6: Used to hold packing material. Valve cover 4: Responsible for sealing, supporting the valve stem, connecting the actuator, and tightening the sealing packing. Threaded sleeve 13: Provides good radial support and guidance during the up-and-down movement of the valve stem, preventing the valve stem from wobbling.

[0039] The above embodiments are merely exemplary embodiments of the present invention and are not intended to limit the present invention. The scope of protection of the present invention is defined by the claims. Those skilled in the art can make various modifications or equivalent substitutions to the present invention within its spirit and scope of protection, and such modifications or equivalent substitutions should also be considered to fall within the scope of protection of the present invention.

Claims

1. A cryogenic shut-off check valve with a pressure-reducing valve disc, characterized in that, The cryogenic shut-off check valve with a pressure-reducing orifice disc includes: A valve body (1) having an internal cavity (100); A valve stem (5) is inserted into the internal cavity (100) of the valve body (1) from one end and is movable along the length direction; A valve disc (2) is movably disposed in the internal cavity (100). The valve disc (2) moves along the length direction via the valve stem (5) to block or connect the inlet side (101) and outlet side (102) of the valve body (1). The valve disc (2) has a limiting structure to limit the movement of the valve disc (2) along the valve stem (5). One end of the valve disc (2) is used to block or connect the inlet side (101) and outlet side (102) of the valve body. On the outlet side (102), the valve disc (2) has a movable cavity (20). An inner hole is provided at one end of the valve disc (2) to communicate with the outside. The valve stem (5) is inserted into the movable cavity (20) through the inner hole (201). A pressure reducing hole (202) is provided around the side wall of the inner hole (201) so that when the valve stem (5) is raised, the medium flowing into the outlet side (101) is reduced in pressure.

2. The cryogenic shut-off check valve with a pressure-reducing valve disc according to claim 1, characterized in that, When the valve stem (5) is pressed to the bottom, the water inside the active chamber (20) flows out through the pressure relief hole (202).

3. The cryogenic shut-off check valve with a pressure-reducing valve disc according to claim 2, characterized in that, The valve body (1) has a first step (103) in its internal cavity (100) so that when the valve stem (5) moves in the lifting direction, the valve disc (2) is limited to the position of the first step (103).

4. The cryogenic shut-off check valve with a pressure-reducing valve disc according to claim 3, characterized in that, When the valve stem (5) moves in the blocking direction, it presses down on the valve disc (2) to block the connecting hole (104) between the water inlet side (101) and the water outlet side (102), thus limiting the blocking direction.

5. The cryogenic shut-off check valve with a pressure-reducing valve disc according to claim 4, characterized in that, The valve stem (5) and the valve body (1) are connected by a thread to achieve bidirectional movement along the length of the valve stem (5).

6. The cryogenic shut-off check valve with a pressure-reducing valve disc according to claim 5, characterized in that, The other end of the valve stem (5) extends out of the valve body (1), and after being rotated by the handwheel (11), it moves in the length direction by the thread.

7. The cryogenic shut-off check valve with a pressure-reducing valve disc according to claim 6, characterized in that, A packing sleeve (8) is provided at the end of the valve body (1) that is inserted into the valve stem (5). There is a packing (7) and a filling pad (6) between the lower end face of the packing sleeve (8) and the second step (105) of the valve body (1). There is an O-ring (17) between the packing sleeve (8) and the valve body (1).

8. The cryogenic shut-off check valve with a pressure-reducing valve disc according to claim 7, characterized in that, The valve body has a valve cover (4), which is penetrated by the valve stem (5), and a threaded sleeve (13) is provided at one end of the valve stem (5) extending outward.

9. The cryogenic shut-off check valve with a pressure-reducing valve disc according to claim 8, characterized in that, The valve stem (5) has a top cover at one end, and the top cover is threaded onto the top of the valve body (1) to press the packing sleeve (8). A hexagonal locking nut (9) is provided at the lower end of the top cover.

10. The cryogenic shut-off check valve with a pressure-reducing valve disc according to claim 9, characterized in that, The valve cover (4) is fixed by an internal hexagon head screw (14).

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