Isolation gate valve for nuclear power

Abstract

The utility model relates to the technical field of gate valve discloses a kind of isolation gate valves for nuclear power, comprising: valve body, valve stem, gate structure and hydraulic structure, and flow-through passage is opened in valve body, and flow-through passage includes liquid inlet passage, middle cavity and liquid outlet passage;Valve stem is installed in valve body;Gate structure is installed on valve stem, and valve stem drives gate structure to lift to connect or cut off liquid inlet passage and liquid outlet passage;Pressure relief structure is communicated with liquid inlet passage, middle cavity and liquid outlet passage, and pressure relief structure is used to make middle cavity and liquid inlet passage or liquid outlet passage side with higher pressure communicate, to balance middle cavity pressure. When gate valve needs to be from cut-off medium flow-through state, lift gate structure becomes the process of realizing medium flow-through state, and middle cavity pressure abnormally rises, at this time, pressure relief structure is self-started, high-pressure medium can flow into liquid inlet passage or liquid outlet passage by pressure relief structure, and pressure is automatically balanced, reduce the risk of valve damage.

Description

Technical Field

[0001] This utility model relates to the field of gate valve technology, specifically to an isolation gate valve for nuclear power plants. Background Technology

[0002] Isolation gate valves are among the key pieces of equipment in nuclear power plants, especially during nuclear island accidents, where their reliability and sealing performance directly affect nuclear safety and the stability of system operation. Currently, the isolation gate valves widely used in the nuclear power industry mainly adopt wedge-shaped single-gate or parallel double-gate structures. Wedge-shaped gate valves have a compact structure and good sealing performance, but under high temperature and high pressure conditions, they are prone to jamming due to thermal expansion or media deposition, and may even fail to open and close normally. While the parallel double-gate structure alleviates the jamming problem to some extent, its sealing effect is not ideal under low pressure conditions, making it difficult to meet the high requirements of zero leakage in nuclear power systems.

[0003] In addition, the cavity of a traditional gate valve is prone to a "boiler effect" due to temperature changes, which leads to abnormal pressure rise in the cavity, further increasing the opening and closing torque and exacerbating the risk of valve damage. Utility Model Content

[0004] In view of this, the present invention provides an isolation gate valve for nuclear power plants to solve the problem that the cavity of traditional gate valves is prone to "boiler effect" due to temperature changes, which leads to abnormal pressure rise in the cavity, further increases the opening and closing torque, and exacerbates the risk of valve damage.

[0005] In a first aspect, this utility model provides an isolation gate valve for nuclear power plants, comprising:

[0006] The valve body has a flow channel, which includes an inlet channel, a middle cavity, and an outlet channel.

[0007] A valve stem, which is mounted in the valve body;

[0008] A gate structure is mounted on the valve stem, and the valve stem drives the gate structure to rise and fall to connect or disconnect the inlet channel and the outlet channel;

[0009] The pressure relief structure is connected to the inlet channel, the middle cavity, and the outlet channel. The pressure relief structure is used to connect the middle cavity to the side with higher pressure in the inlet channel or the outlet channel to balance the pressure in the middle cavity.

[0010] Beneficial effects: When media flow is required, the drive device receives a command and drives the valve stem to rotate and lift. The valve stem drives the gate structure to move upward, disengaging from the valve seat between the inlet and outlet channels, thus opening the connection between the inlet and outlet channels and allowing media flow.

[0011] When it is necessary to cut off the flow of media, the drive unit receives a command and drives the valve stem to rotate in the opposite direction and press down, pushing the gate structure downward. The gate structure presses against its respective valve seat, forming a metal seal and isolating the inlet and outlet channels.

[0012] When a gate valve needs to change from a state of cutting off the flow of medium to a state of allowing the flow of medium by raising the gate structure, if there is an abnormal increase in the pressure in the middle cavity, the pressure relief structure will automatically start. The high-pressure medium will flow into the inlet or outlet channel through the pressure relief structure, and the pressure will automatically balance, reducing the risk of valve damage.

[0013] In one optional implementation, the pressure relief structure includes:

[0014] Pressure relief components;

[0015] The first branch has one end connected to the pressure relief assembly and the other end connected to the liquid inlet channel;

[0016] The second branch has one end connected to the pressure relief assembly and the other end connected to the central cavity;

[0017] The third branch has one end connected to the pressure relief assembly and the other end connected to the liquid storage channel.

[0018] In one optional implementation, the pressure relief assembly includes:

[0019] The pressure relief assembly body has an installation cavity, a first passage, and a second passage.

[0020] A first support member and a second support member are installed in the mounting cavity through a fixing unit. The first support member and the second support member are symmetrically arranged, and the first support member, the second support member, and the inner wall of the mounting cavity form a pressure relief cavity.

[0021] A sliding member, which is movably mounted within the pressure relief chamber.

[0022] In one optional embodiment, the first support member has a first transition channel; the second support member has a second transition channel.

[0023] One end of the first passage is connected to the first branch, and the other end is connected to the first transition channel;

[0024] One end of the second passage is connected to the second branch, and the other end is connected to the second transition channel;

[0025] The end of the third branch away from the valve body is connected to the pressure relief chamber.

[0026] In one alternative embodiment, the sliding member includes:

[0027] Sliding section;

[0028] A first pressure relief section and a second pressure relief section are provided at both ends of the sliding section; a first pressure relief channel is provided on the first pressure relief section and a second pressure relief channel is provided on the second pressure relief section;

[0029] Under the action of external force, the sliding part can drive the second pressure relief part to move toward the direction of the second support member and insert into the second transition channel, so that one end of the first pressure relief channel is connected to the first transition channel and the other end is connected to the pressure relief cavity;

[0030] or

[0031] The sliding part can drive the second pressure relief part to move toward the direction of the first support member and insert it into the first transition channel, so that one end of the second pressure relief channel is connected to the second transition channel and the other end is connected to the pressure relief cavity.

[0032] In one optional embodiment, the pressure relief assembly further includes: a first adjustment unit and a second adjustment unit, wherein the first adjustment unit extends through the pressure relief assembly body and into the first passage, and the first adjustment unit is used to disconnect or connect the first passage.

[0033] The second adjustment unit extends through the pressure relief assembly body and into the second passage, and the second adjustment unit is used to disconnect or connect the second passage.

[0034] Beneficial effects: When pressure relief is required in the middle cavity, there are multiple operating conditions: First, the pressure in the inlet channel is greater than the pressure in the outlet channel. The medium in the inlet channel enters the first passage through the first branch, and then generates a rightward thrust on the left end of the sliding part through the first transition channel. At this time, the entire sliding part moves to the right towards the second support, and the second pressure relief part is inserted into the second transition channel. The opening at the end of the first pressure relief channel is connected to the first transition channel, and the opening on the other side wall is connected to the pressure relief chamber. This achieves the connection between the inlet channel, the first branch, the first passage, the first transition channel, the first pressure relief channel, and the pressure relief chamber. At this time, the medium in the middle cavity enters the pressure relief chamber through the third branch. Through the pressure relief chamber, the first pressure relief channel, the first transition channel, the first passage, the first branch, and the inlet channel, the high-pressure medium in the middle cavity is reversed and introduced into the inlet channel, thus relieving the pressure in the middle cavity.

[0035] In the second configuration, the pressure in the outlet channel is greater than that in the inlet channel. The medium in the outlet channel enters the second passage through the second branch, and then exerts a leftward thrust on the right end of the sliding part through the second transition channel. At this time, the entire sliding part moves to the left towards the first support member. The first pressure relief part is inserted into the first transition channel. The opening at the end of the second pressure relief channel is connected to the second transition channel, and the opening on the other side wall is connected to the pressure relief chamber. This achieves the connection between the inlet channel, the second branch, the second passage, the second transition channel, the second pressure relief channel, and the pressure relief chamber. At this time, the medium in the middle cavity enters the pressure relief chamber through the third branch. Through the pressure relief chamber, the second pressure relief channel, the second transition channel, the second passage, the second branch, and the inlet channel, the high-pressure medium in the middle cavity is reversed and introduced into the outlet channel, thus relieving the pressure in the middle cavity.

[0036] By implementing the above design, compared to existing power-driven shut-off valves for pressure relief, control and maintenance costs are significantly reduced, valve manufacturing costs are greatly lowered, and valve installation components are reduced, resulting in a more aesthetically pleasing and reliable design. Furthermore, the valve cavity can only be connected to the side with the higher medium pressure, preventing leakage from the main valve via a bypass line.

[0037] In one optional embodiment, the gate structure includes:

[0038] Two wedge-shaped gates are provided, which are arranged opposite to each other, and the inner sidewall of each wedge-shaped gate is provided with an installation groove.

[0039] Support member, which is installed in the mounting groove;

[0040] The support member is configured as an annular shape, and the mounting groove is configured as a circular groove corresponding to the support member.

[0041] Beneficial effects: Two wedge-shaped gates and a support member combine to form a valve disc, used to isolate or connect the inlet and outlet channels. The support member and the wedge-shaped gates have surface contact, which makes the valve more stable and durable. Over prolonged operation, the two wedge-shaped gates will inevitably wear. By using a ring-shaped support member, after removing the gate structure, only the support member of different thicknesses needs to be replaced according to the wear of the two wedge-shaped gates. This automatically compensates for slight asymmetrical wear, avoiding the need for repeated valve replacement during gate valve maintenance.

[0042] In one optional embodiment, a T-slot is provided at the top of the wedge-shaped gate, and a T-shaped mounting piece is provided at the bottom of the valve stem corresponding to the T-slot;

[0043] The T-shaped mounting component is inserted into the T-shaped groove.

[0044] In one optional embodiment, a compensation cavity is provided on the valve body, and the inner diameter of the compensation cavity is larger than the outer diameter of the valve stem;

[0045] The nuclear power plant isolation gate valve also includes a fixing ring and a high-temperature compensation structure, wherein the fixing ring restricts the high-temperature compensation structure to be installed within the compensation cavity.

[0046] In one alternative embodiment, the valve stem has an annular protrusion on its sidewall;

[0047] The high-temperature compensation structure includes:

[0048] The first limiting member and the second limiting member are sleeved on the valve stem, and the first limiting member and the second limiting member are respectively disposed on both sides of the protrusion;

[0049] The compensating member is sleeved on the valve stem and installed on the side of the second limiting member away from the first limiting member. There is a gap between the end of the compensating member away from the second limiting member and the fixing ring.

[0050] An elastic element is installed between the compensation element and the valve body, and the elastic element provides the compensation element with a spring force toward the fixed ring.

[0051] Beneficial effects: Under normal circumstances, there is a gap between the end of the compensating member away from the second limiting member and the fixing ring. The elastic element is installed between the compensating member and the valve body. The elastic element can provide the compensating member with a spring-like force moving away from the fixing ring to axially fix the valve stem. The elastic element is a spring.

[0052] When the valve is closed, the increased medium temperature causes the valve stem to elongate due to heat. The protruding part pushes the compensating member upward through the second limiting member. Because there is a gap between the end of the compensating member away from the second limiting member and the fixing ring, this gap allows the valve stem nut to compensate for displacement within a set range, preventing deformation of the valve stem under stress, solving the thermal expansion problem, and improving safety and reliability. In this process, the compensation is completed entirely by the adaptive mechanical structure, without the need for sensors, control systems, or manual operation, resulting in rapid response and extremely high reliability. When the system temperature drops and the valve stem contracts, the compressed elastic element releases energy, pushing the compensating member downward and resetting the second limiting member, preparing for the next thermal cycle. Attached Figure Description

[0053] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0054] Figure 1 This is an isometric view of an isolation gate valve for nuclear power plants according to an embodiment of the present invention;

[0055] Figure 2 This is a schematic diagram of the pressure relief structure in an embodiment of the present invention;

[0056] Figure 3 This is a schematic diagram of the gate structure in an embodiment of the present utility model;

[0057] Figure 4 This is a schematic diagram of the high-temperature compensation structure in an embodiment of the present invention;

[0058] Explanation of reference numerals in the attached figures:

[0059] 1. Valve body; 11. Compensation chamber;

[0060] 2. Valve stem; 21. Protrusion;

[0061] 3. Gate structure; 31. Wedge-shaped gate; 32. Supporting components;

[0062] 4. Pressure relief structure; 41. Pressure relief assembly; 411. Pressure relief assembly body; 412. Mounting cavity; 413. First passage; 414. Second passage; 415. First support member; 416. First transition channel; 417. Second support member; 418. Second transition channel; 419. Sliding member; 420. Sliding part; 421. First pressure relief part; 422. First pressure relief channel; 423. Second pressure relief part; 424. Second pressure relief channel; 425. First adjustment unit; 426. Second adjustment unit; 427. Fixing unit; 42. First branch; 43. Second branch; 44. Third branch;

[0063] 51. First limiting component; 52. Second limiting component; 53. Compensating component; 54. Elastic component. Detailed Implementation

[0064] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0065] Isolation gate valves are among the key pieces of equipment in nuclear power plants, especially during nuclear island accidents, where their reliability and sealing performance directly affect nuclear safety and the stability of system operation. Currently, the isolation gate valves widely used in the nuclear power industry mainly adopt wedge-shaped single-gate or parallel double-gate structures. Wedge-shaped gate valves have a compact structure and good sealing performance, but under high temperature and high pressure conditions, they are prone to jamming due to thermal expansion or media deposition, and may even fail to open and close normally. While the parallel double-gate structure alleviates the jamming problem to some extent, its sealing effect is not ideal under low pressure conditions, making it difficult to meet the high requirements of zero leakage in nuclear power systems.

[0066] In addition, the cavity of a traditional gate valve is prone to a "boiler effect" due to temperature changes, which leads to abnormal pressure rise in the cavity, further increasing the opening and closing torque and exacerbating the risk of valve damage.

[0067] To solve the above technical problems, the following will be combined with... Figures 1 to 4 The following describes embodiments of the present invention.

[0068] According to an embodiment of the present invention, an isolation gate valve for nuclear power plants is provided, comprising: a valve body 1, a valve stem 2, a gate structure 3, and a pressure relief structure 4.

[0069] like Figure 1 As shown, the valve body 1 is a three-way structure made of casting or forging, with a horizontal flow channel inside. The two ends of the channel are the inlet channel and the outlet channel, respectively. A cavity, called the central cavity, is located above the middle of the flow channel. The valve stem 2 is installed inside the valve body 1. The upper end of the valve stem 2 passes through the valve cover and connects to the drive device, while the lower end connects to the gate structure 3. Part of the valve stem 2 is located within the central cavity. The pressure relief structure 4 is connected to the inlet channel, the central cavity, and the outlet channel. The pressure relief structure 4 is used to connect the central cavity to the side with the higher pressure in either the inlet or outlet channel to balance the pressure in the central cavity.

[0070] When media flow is required, the drive unit receives a command and drives the valve stem 2 to rotate and lift. The valve stem 2 drives the gate structure 3 to move upward as a whole, disengaging from the valve seat between the inlet and outlet channels. The inlet and outlet channels are then connected and opened, allowing media flow.

[0071] When it is necessary to cut off the flow of media, the drive unit receives the command and drives the valve stem 2 to rotate in the opposite direction and press down, pushing the gate structure 3 downward. The gate structure 3 is pressed against its respective valve seat to form a metal seal, thereby isolating the inlet and outlet channels.

[0072] When the gate valve needs to change from the state of cutting off the flow of medium to the state of allowing the flow of medium by raising the gate structure 3, if the pressure in the middle cavity rises abnormally, the pressure relief structure 4 will start automatically. The high-pressure medium will flow into the inlet or outlet channel through the pressure relief structure 4, and the pressure will be automatically balanced, reducing the risk of valve damage.

[0073] In this embodiment, as Figure 1 and 2 As shown, the pressure relief structure 4 includes: a pressure relief assembly 41, a first branch 42, a second branch 43, and a third branch 44. The first branch 42, the second branch 43, and the third branch 44 are pipelines, fixed to the valve body 1 and the pressure relief assembly 41 via flanges. One end of the first branch 42 is connected to the pressure relief assembly 41, and the other end is connected to the liquid inlet channel; one end of the second branch 43 is connected to the pressure relief assembly 41, and the other end is connected to the central cavity; one end of the third branch 44 is connected to the pressure relief assembly 41, and the other end is connected to the liquid storage channel.

[0074] The pressure relief assembly 41 includes: a pressure relief assembly body 411, a first support member 415, a second support member 417, and a sliding member 419. The bottom end of the pressure relief assembly body 411 has a horizontally formed mounting cavity 412. The end of the pressure relief assembly body 411 near the first branch 42 has a first passageway 413, and the end of the pressure relief assembly body 411 near the second branch 43 has a second passageway 414. The first support member 415 and the second support member 417 are installed in the mounting cavity 412 via a fixing unit 427. The fixing unit 427 can be a convex structure. Bolts are used to secure the first support member 415 and the second support member 417 to the left and right sides of the mounting cavity 412, respectively. The first support member 415 and the second support member 417 are symmetrically spaced apart, with a certain distance between them. The first support member 415, the second support member 417, and the inner wall of the mounting cavity 412 together form a pressure relief cavity. The first support member 415 has a first transition channel 416, and the second support member 417 has a second transition channel 418.

[0075] The left end of the first passage 413 passes through the left end of the pressure relief assembly body 411 and connects to the first branch 42. The other end of the first passage 413 connects to the first transition channel 416. The right end of the second passage 414 passes through the right end of the pressure relief assembly body 411 and connects to the second branch 43. The other end of the second passage 414 connects to the second transition channel 418. The end of the third branch 44 furthest from the valve body 1 connects to the pressure relief chamber.

[0076] The sliding member 419 is movably installed inside the pressure relief chamber. Specifically, the sliding member 419 includes a sliding part 420, a first pressure relief part 421, and a second pressure relief part 423, with the first pressure relief part 421 and the second pressure relief part 423 respectively located at both ends of the sliding part 420; the first pressure relief part 421 has a first pressure relief channel 422, and the second pressure relief part 423 has a second pressure relief channel 424.

[0077] One opening of the first pressure relief channel 422 is located at the end of the first pressure relief part 421 away from the sliding part 420, and the other opening is located on the side wall of the end near the sliding part 420. One opening of the second pressure relief channel 424 is located at the end of the second pressure relief part 423 away from the sliding part 420, and the other opening is located on the side wall of the second pressure relief part 423 near the sliding part 420.

[0078] When pressure relief is required in the middle cavity, there are several operating conditions: First, the pressure in the inlet channel is greater than the pressure in the outlet channel. The medium in the inlet channel enters the first passage 413 through the first branch 42, and then generates a rightward thrust on the left end of the sliding part 420 through the first transition channel 416. At this time, the entire sliding part 419 moves to the right towards the second support 417, and the second pressure relief part 423 is inserted into the second transition channel 418. The opening at the end of the first pressure relief channel 422 is connected to the first transition channel 416, and the opening on the other side wall is connected to the pressure relief chamber. The connection between the liquid inlet channel, the first branch 42, the first passage 413, the first transition channel 416, the first pressure relief channel 422 and the pressure relief chamber is realized. At this time, the medium in the middle cavity enters the pressure relief chamber through the third branch 44. Through the pressure relief chamber, the first pressure relief channel 422, the first transition channel 416, the first passage 413, the first branch 42 and the liquid inlet channel, the high pressure medium in the middle cavity is reversed and introduced into the liquid inlet channel to relieve the pressure in the middle cavity.

[0079] In the second scenario, the pressure in the outlet channel is greater than the pressure in the inlet channel. The medium in the outlet channel enters the second passage 414 through the second branch 43, and then exerts a leftward thrust on the right end of the sliding part 420 through the second transition channel 418. At this time, the entire sliding part 419 moves to the left towards the first support 415, and the first pressure relief part 421 is inserted into the first transition channel 416. The opening at the end of the second pressure relief channel 424 is connected to the second transition channel 418, and the opening on the other side wall is connected to the pressure relief chamber. This achieves the connection between the inlet channel, the second branch 43, the second passage 414, the second transition channel 418, the second pressure relief channel 424, and the pressure relief chamber. At this time, the medium in the middle cavity enters the pressure relief chamber through the third branch 44. Through the pressure relief chamber, the second pressure relief channel 424, the second transition channel 418, the second passage 414, the second branch 43, and the inlet channel, the high-pressure medium in the middle cavity is reversed and introduced into the outlet channel, thus relieving the pressure in the middle cavity.

[0080] By implementing the above design, compared to existing power-driven shut-off valves for pressure relief, control and maintenance costs are significantly reduced, valve manufacturing costs are greatly lowered, and valve installation components are reduced, resulting in a more aesthetically pleasing and reliable design. Furthermore, the valve cavity can only be connected to the side with the higher medium pressure, preventing leakage from the main valve via a bypass line.

[0081] In this embodiment, as Figure 2 As shown, the pressure relief assembly 41 also includes a first adjusting unit 425 and a second adjusting unit 426. The first adjusting unit 425 and the second adjusting unit 426 have the same structure and are symmetrically inclined. The structure of the first adjusting unit 425 and the second adjusting unit 426 is similar to the combination structure of the valve stem 2 and the handle. Taking one of the adjusting units as an example, its specific structure includes: an adjusting fixing member, an adjusting rod, and an adjusting handle. The adjusting fixing member is fixed to the pressure relief assembly body 411. The adjusting rod passes through the adjusting fixing member, and one end of the adjusting rod passes through the pressure relief assembly body 411 and extends into the corresponding passage. A sealing plug is also provided at the end of the adjusting rod that extends into the passage. The handle is rotatably mounted on the adjusting fixing member, and the handle is threadedly connected to the adjusting rod. By rotating the handle, the adjusting rod and the sealing plug mounted on it can be moved upward along its axial direction, disengaging from the passage and realizing the connection of the passage. Alternatively, by rotating the handle in the opposite direction, the adjusting rod and the sealing plug mounted on it can be moved downward along its axial direction, and the sealing plug is re-inserted into the passage, realizing the closure of the passage. The adjusting rod in the first adjusting unit 425 passes through the pressure relief assembly body 411 and extends into the first passage 413. The first adjusting unit 425 is used to disconnect or connect the first passage 413. The adjusting rod in the second adjusting unit 426 passes through the pressure relief assembly body 411 and extends into the second passage 414. The second adjusting unit 426 is used to disconnect or connect the second passage 414.

[0082] During normal operation of the gate valve, the first regulating unit 425 isolates the first passage 413, and the second regulating unit 426 isolates the second passage 414. When the pressure in the middle cavity is too high and pressure relief is required, the first regulating unit 425 and the second regulating unit 426 are adjusted to connect the first passage 413 and the second passage 414, thereby enabling the pressure relief assembly 41 to operate normally.

[0083] In this embodiment, as Figure 3 As shown, the gate structure 3 includes: a wedge-shaped gate 31 and a support member 32. Two wedge-shaped gates 31 are provided and are arranged opposite to each other. The inner sidewall of the wedge-shaped gate 31 is provided with an installation groove. The support member 32 is installed in the installation groove. The support member 32 is set in a circular shape, and the installation groove is set in a circular groove corresponding to the support member 32.

[0084] Two wedge-shaped gates 31 and a support member 32 combine to form a valve disc, used to isolate or connect the inlet and outlet channels. The support member 32 and the wedge-shaped gates 31 are in surface contact; this surface contact support method makes the valve more stable and durable. Under prolonged operation, the two wedge-shaped gates 31 will inevitably wear down. By using the annular support member 32, after removing the gate structure 3, only the support member 32 of different thicknesses needs to be replaced according to the wear of the two wedge-shaped gates 31. This automatically compensates for slight asymmetrical wear, avoiding the need for repeated valve replacement during gate valve maintenance.

[0085] In this embodiment, as Figure 3 As shown, a T-shaped groove is provided at the top of the wedge gate 31, and a T-shaped mounting piece is provided at the bottom of the valve stem 2 corresponding to the T-shaped groove; the T-shaped mounting piece is inserted into the T-shaped groove.

[0086] Both wedge-shaped gates 31 have mounting guide plates on their sides, and a U-shaped guide groove is welded inside the valve body 1. The two mounting guide plates on the two wedge-shaped gates 31 are installed in the U-shaped guide groove to complete the installation of the gate structure 3. When the drive device rotates, the valve stem 2 rotates accordingly and makes a vertical linear movement. The T-shaped mounting piece at the bottom of the valve stem 2 effectively transmits its vertical thrust and pull forces to the entire gate structure 3 through the vertical force-bearing surfaces on both sides of the T-shaped groove, driving it to complete the upward and downward movements. The T-shaped mounting piece and the T-shaped groove also facilitate the installation and disassembly of the gate structure 3.

[0087] In this embodiment, as Figure 4As shown, the valve stem 2 has an annular protrusion 21 on its side wall. A compensation cavity 11 is provided on the valve body 1, the inner diameter of which is larger than the outer diameter of the valve stem 2. The nuclear power plant isolation gate valve also includes a fixing ring and a high-temperature compensation structure. The fixing ring confines the high-temperature compensation structure within the compensation cavity 11. Specifically, the high-temperature compensation structure includes: a first limiting member 51, a second limiting member 52, a compensation member 53, and an elastic member 54. Both the first limiting member 51 and the second limiting member 52 are annular. The first limiting member 51 and the second limiting member 52 are sleeved on the valve stem 2, and the second limiting member 52 and the first limiting member 51 are respectively located on the upper and lower sides of the protrusion 21. The compensation member 53 is an L-shaped sleeve, sleeved on the valve stem 2, and installed on the side of the second limiting member 52 away from the first limiting member 51. That is, the lower surface of the first limiting member 51 is attached to the bottom surface of the compensation cavity 11, the upper surface of the first limiting member 51 is attached to the lower surface of the protrusion 21, the lower surface of the second limiting member 52 is attached to the upper surface of the protrusion 21, and the upper surface of the second limiting member 52 is attached to the lower surface of the compensation member 53.

[0088] Under normal circumstances, there is a gap between the end of the compensating member 53 away from the second limiting member 52 and the fixing ring. The elastic member 54 is installed between the compensating member 53 and the valve body 1. The elastic member 54 can provide the compensating member 53 with a spring-like force away from the fixing ring to axially fix the valve stem 2. The elastic member 54 is a spring.

[0089] When the valve is closed, the increased medium temperature causes the valve stem 2 to elongate due to heat. The protrusion 21 pushes the compensation member 53 upward via the second limiting member 52. Because there is a gap between the end of the compensation member 53 away from the second limiting member 52 and the fixing ring, this gap allows the valve stem 2 nut to compensate for displacement within a set range, preventing deformation of the valve stem 2 under stress, solving the thermal expansion problem, and improving safety and reliability. In this process, the compensation is completed entirely by the adaptive mechanical structure, requiring no sensors, control systems, or human operation, resulting in rapid response and extremely high reliability. When the system temperature drops and the valve stem 2 contracts, the compressed elastic member 54 releases energy, pushing the compensation member 53 downward and resetting the second limiting member 52, preparing for the next thermal cycle.

[0090] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the appended claims.

Claims

1. An isolation gate valve for nuclear power plants, characterized in that, include: The valve body (1) has a flow channel inside, which includes an inlet channel, a middle cavity and an outlet channel; Valve stem (2), which is installed inside the valve body (1); A gate structure (3) is mounted on the valve stem (2), and the valve stem (2) drives the gate structure (3) to move up and down to connect or disconnect the inlet channel and the outlet channel; The pressure relief structure (4) is connected to the liquid inlet channel, the middle cavity and the liquid outlet channel. The pressure relief structure (4) is used to connect the middle cavity with the side with higher pressure in the liquid inlet channel or the liquid outlet channel to balance the pressure in the middle cavity.

2. The isolation gate valve for nuclear power plants according to claim 1, characterized by The pressure relief structure (4) includes: Pressure relief assembly (41); The first branch (42) has one end connected to the pressure relief assembly (41) and the other end connected to the liquid inlet channel; The second branch (43) has one end connected to the pressure relief assembly (41) and the other end connected to the central cavity; The third branch (44) is connected at one end to the pressure relief assembly (41) and at the other end to the liquid storage channel.

3. The isolation gate valve for nuclear power plants according to claim 2, characterized by The pressure relief assembly (41) includes: The pressure relief assembly body (411) has an installation cavity (412), a first passage (413) and a second passage (414) on it; A first support member (415) and a second support member (417) are installed in the mounting cavity (412) by a fixing unit (427). The first support member (415) and the second support member (417) are symmetrically arranged. The first support member (415), the second support member (417) and the inner wall of the mounting cavity (412) form a pressure relief cavity. A sliding member (419) is movably installed within the pressure relief chamber.

4. The isolation gate valve for nuclear power plants according to claim 3, characterized by The first support member (415) has a first transition channel (416); the second support member (417) has a second transition channel (418); One end of the first passage (413) is connected to the first branch (42), and the other end is connected to the first transition channel (416); One end of the second passage (414) is connected to the second branch (43), and the other end is connected to the second transition channel (418); The end of the third branch (44) away from the valve body (1) is connected to the pressure relief chamber.

5. The isolation gate valve for nuclear power plants according to claim 4, characterized by The sliding member (419) includes: Sliding part (420); The first pressure relief part (421) and the second pressure relief part (423) are respectively disposed at both ends of the sliding part (420); the first pressure relief part (421) is provided with a first pressure relief channel (422), and the second pressure relief part (423) is provided with a second pressure relief channel (424); Under the action of external force, the sliding part (420) can drive the second pressure relief part (423) to move toward the direction close to the second support (417) and insert into the second transition channel (418), so that one end of the first pressure relief channel (422) is connected to the first transition channel (416) and the other end is connected to the pressure relief cavity; or The sliding part (420) can drive the second pressure relief part (423) to move toward the first support (415) and insert into the first transition channel (416), so that one end of the second pressure relief channel (424) is connected to the second transition channel (418) and the other end is connected to the pressure relief cavity.

6. The isolation gate valve for nuclear power plants according to claim 3, characterized by The pressure relief assembly (41) further includes: a first adjustment unit (425) and a second adjustment unit (426), wherein the first adjustment unit (425) passes through the pressure relief assembly body (411) and extends into the first passage (413), and the first adjustment unit (425) is used to disconnect or connect the first passage (413); The second adjustment unit (426) extends through the pressure relief assembly body (411) and into the second passage (414), and the second adjustment unit (426) is used to disconnect or connect the second passage (414).

7. The isolation gate valve for nuclear power plants according to claim 1, characterized by The gate structure (3) includes: Two wedge-shaped gates (31) are provided, and the two wedge-shaped gates (31) are arranged opposite to each other. The inner sidewall of the wedge-shaped gate (31) is provided with an installation groove. A support member (32) is installed in the mounting groove; The support member (32) is configured as an annular shape, and the mounting groove is configured as a circular groove corresponding to the support member (32).

8. The isolation gate valve for nuclear power plants according to claim 7, characterized by The top of the wedge-shaped gate (31) is provided with a T-shaped groove, and the bottom of the valve stem (2) is provided with a T-shaped mounting piece corresponding to the T-shaped groove; The T-shaped mounting component is inserted into the T-shaped groove.

9. The isolation gate valve for nuclear power plants according to claim 1, characterized by The valve body (1) is provided with a compensation cavity (11), and the inner diameter of the compensation cavity (11) is larger than the outer diameter of the valve stem (2); The nuclear power isolation gate valve also includes a fixing ring and a high-temperature compensation structure, wherein the fixing ring restricts the high-temperature compensation structure to be installed within the compensation chamber (11).

10. The isolation gate valve for nuclear power plants according to claim 9, characterized by The valve stem (2) has an annular protrusion (21) on its side wall; The high-temperature compensation structure includes: The first limiting member (51) and the second limiting member (52) are sleeved on the valve stem (2) and are respectively disposed on both sides of the protrusion (21). The compensation component (53) is sleeved on the valve stem (2). The compensation component (53) is installed on the side of the second limiting component (52) away from the first limiting component (51). There is a gap between the end of the compensation component (53) away from the second limiting component (52) and the fixing ring. An elastic member (54) is installed between the compensation member (53) and the valve body (1), and the elastic member (54) can provide the compensation member (53) with elastic force away from the fixed ring.

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