Power station check valve using self medium pressure to assist sealing

Abstract

This invention relates to the field of check valve technology and discloses a power plant check valve that utilizes its own medium pressure for assisted sealing. The invention features a corrugated structure. When the valve is opened in the forward direction, the inlet pressure on the left side pushes the corrugated structure's base plate upwards. The fixed rod and movable ring cause the support rod to contract along the trajectory of the limiting slide groove, causing the entire corrugated structure to retract into the movable block. When the valve is closed and the back pressure on the right side increases, the high-pressure liquid enters the inner cavity of the small corrugated structure in the reverse direction, driving the corrugated structure's base plate to move in the reverse direction, thereby pushing the movable ring downwards. When passing the fixed inclined block, it forces the support rod to expand outwards, expanding the large corrugated structure until it tightly adheres to the inner wall of the check valve's flow groove. At this time, the higher the pressure on the right side, the greater the liquid pressure acting on the large corrugated structure, making its expansion and adhesion even tighter, achieving a self-tightening sealing effect where the sealing force increases synchronously with the back pressure.

Description

Technical Field

[0001] This invention relates to the field of check valve technology, and in particular to a power plant check valve that utilizes its own medium pressure for assisted sealing. Background Technology

[0002] A power plant check valve is an automatic valve specifically designed for use in critical high-temperature and high-pressure systems such as boiler feedwater, main steam, reheat steam, and turbine extraction steam in power plants. Its core function is to open and close the valve disc by relying on the flow force of the medium itself, allowing the medium to flow in only one direction and automatically preventing backflow. This protects upstream core equipment such as boilers, turbines, and feedwater pumps from damage caused by reverse fluid impact, making it a key safety device for ensuring the safe operation of power plants.

[0003] According to Chinese Patent Publication No. CN213871248U, this utility model relates to the field of check valve technology and discloses a pressure self-sealing lift check valve, including a check valve body. A fixing block is fixedly connected to the top of the check valve body, a buffer pad is movably connected to the top of the fixing block, a sealing block is movably connected to the top of the buffer pad, a connecting screw is movably connected to the inner side of the sealing block, a connecting nut is threadedly connected to the outer side of the connecting screw, a threaded block is fixedly connected to the top of the sealing block, and a threaded rod is threadedly connected to the inner side of the threaded block. This pressure self-sealing lift check valve achieves the purpose of good sealing effect of the lift check valve, eliminating the need for sealing tape and the worry of sealing tape aging. It effectively seals the lift check valve, preventing liquid leakage from the inside of the lift check valve, avoiding water waste, and improving the efficiency and effect of the lift check valve.

[0004] The above-mentioned and existing related technologies have the following drawbacks: When the back pressure on the outlet side increases or fluctuates in the closed state, the valve disc sealing force cannot increase synchronously with the back pressure, resulting in unreliable sealing and easy internal leakage. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the existing technology has the disadvantage of increased back pressure on the outlet side, which leads to internal leakage. To address this, we propose a power plant check valve that uses its own medium pressure to assist in sealing.

[0006] To achieve the above objectives, this application adopts the following technical solution: a power plant check valve that utilizes its own medium pressure for assisted sealing, comprising: a power plant check valve body; a check valve flow block fixedly connected inside the power plant check valve body; a check valve flow groove opened inside the check valve flow block; a movable block slidably connected inside the check valve flow groove; a fixed block fixedly connected inside the movable block; a connecting column fixedly connected to the top of the fixed block; a support spring fixedly connected to the top of the connecting column; a small corrugated structure fixedly connected to the bottom of the movable block; a large corrugated structure fixedly connected to the bottom of the small corrugated structure; a corrugated structure base plate fixedly connected to the bottom of the large corrugated structure; a telescopic rod structure fixedly connected to the bottom of the fixed block; a movable ring slidably connected to the outer wall of the telescopic rod structure; a limit cover fixedly connected to the side of the movable ring; a connecting rod slidably connected inside the limit cover; a support rod fixedly connected to one end of the connecting rod; a sliding ball fixedly connected to the other end of the connecting rod; a fixed inclined block fixedly connected to the bottom of the telescopic rod structure; and limit grooves opened inside both the fixed inclined block and the telescopic rod structure.

[0007] Preferably, the support spring and the power station check valve body are fixedly connected, and the support spring plays the role of elastic support.

[0008] Preferably, the movable block and the fixed block are connected by a connecting block, and a hollow groove is provided between the movable block and the fixed block.

[0009] Preferably, when the movable ring moves down to the position of the fixed inclined block, the support rod moves radially outward under the action of the inclined surface of the fixed inclined block, and completes the outward expansion in conjunction with the limiting slide groove.

[0010] Preferably, the outer wall of the large corrugated structure is provided with a wear-resistant sealing layer, which is made of polytetrafluoroethylene.

[0011] Preferably, the support rod is fixedly connected to the large corrugated structure, and the support rod is located in the middle of the large corrugated structure.

[0012] Preferably, the support rod is arc-shaped, and there are four support rods arranged at equal angles to the vertical central axis of the telescopic rod structure.

[0013] Preferably, the fixed inclined blocks are arranged in a triangular shape, and four fixed inclined blocks are arranged at equal angles with respect to the vertical central axis of the telescopic rod structure.

[0014] Preferably, the sliding ball and the limiting groove are slidably connected, and the limiting groove is provided at four equal angles about the vertical central axis of the telescopic rod structure.

[0015] Preferably, a fixing rod is fixedly connected to the bottom of the movable ring, and the fixing rod is fixedly connected to the corrugated base plate.

[0016] The technical effects and advantages of this invention are as follows:

[0017] In this invention, a corrugated structure is provided. When the valve is opened in the forward direction, the water inlet pressure on the left side pushes the bottom plate of the corrugated structure upward. The fixed rod and the movable ring drive the support rod to contract along the trajectory of the limiting slide groove, causing the entire corrugated structure to retract into the movable block. When the valve is closed and the back pressure on the right side increases, the high-pressure liquid enters the inner cavity of the small corrugated structure in the reverse direction, driving the bottom plate of the corrugated structure to move in the reverse direction, thereby pushing the movable ring downward. When passing the fixed inclined block, it forces the support rod to expand outward, expanding the large corrugated structure until it is tightly fitted with the inner wall of the check valve flow groove. At this time, the higher the pressure on the right side, the greater the liquid pressure acting on the large corrugated structure, making it expand and fit more tightly, thus achieving a self-tightening sealing effect where the sealing force increases synchronously with the back pressure. Attached Figure Description

[0018] The disclosure of this invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of this invention. In the drawings, the same reference numerals are used to refer to the same parts:

[0019] Figure 1 This is a schematic cross-sectional view of the power plant check valve of the present invention.

[0020] Figure 2 This is a front view schematic diagram of the power plant check valve of the present invention;

[0021] Figure 3 This is a schematic diagram of the internal structure of the power plant check valve of the present invention;

[0022] Figure 4 This is a schematic diagram of the structure of the check valve flow block portion of the present invention;

[0023] Figure 5 This is a schematic diagram of the structure of the movable block portion of the present invention;

[0024] Figure 6 This is a cross-sectional structural diagram of the corrugated structure portion of the present invention;

[0025] Figure 7 This is a schematic diagram of the structure of the movable ring portion of the present invention;

[0026] Figure 8 This is a schematic diagram of the fixed inclined block portion of the present invention.

[0027] Legend: 1. Power station check valve body; 2. Check valve flow block; 3. Check valve flow groove; 4. Movable block; 5. Fixed block; 6. Connecting column; 7. Support spring; 8. Small corrugated structure; 9. Large corrugated structure; 10. Corrugated structure base plate; 11. Telescopic rod structure; 12. Movable ring; 13. Limit cover; 14. Connecting rod; 15. Support rod; 16. Sliding ball; 17. Fixed rod; 18. Fixed inclined block; 19. Limit sliding groove. Detailed Implementation

[0028] It is readily understood that, based on the technical solution of this invention, those skilled in the art can propose various interchangeable structural methods and implementations without altering the essential spirit of the invention. Therefore, the following detailed embodiments and accompanying drawings are merely illustrative examples of the technical solution of this invention and should not be considered as the entirety of the invention or as limitations or restrictions on the technical solution of this invention.

[0029] According to the embodiments of the present invention, Figures 1 to 8 As shown.

[0030] A power plant check valve is an automatic valve specifically designed for use in critical high-temperature and high-pressure systems such as boiler feedwater, main steam, reheat steam, and turbine extraction steam in power plants. This valve requires no external drive; it automatically controls the opening and closing of the valve disc solely based on the kinetic energy of the medium's flow and changes in pressure differential within the pipeline. When the medium flows in the specified forward direction, the fluid thrust overcomes the valve disc's own weight or spring force, pushing it open to allow the medium to pass smoothly. Once the medium's flow velocity decreases or a reverse flow trend occurs, the valve disc, under the combined effects of its own weight, the return spring force, and the reverse pressure differential, quickly falls back and tightly adheres to the valve seat, instantly cutting off the flow path. With its one-way flow characteristic, the check valve reliably prevents backflow of high-temperature, high-pressure steam or feedwater. If backflow occurs, the enormous energy carried by the high-speed reverse fluid can trigger severe water hammer and thermal shock, causing severe vibration, damage to sealing surfaces, and even catastrophic damage such as blade breakage and pump shaft bending to upstream core equipment such as boiler heating surfaces, turbine blades, and feedwater pump impellers. Therefore, although the power plant check valve appears simple in structure, it is a key safety barrier to ensure the safe and stable operation of the power plant's thermal circulation system and to prevent major equipment accidents and shutdowns, playing an indispensable protective role in the power plant system.

[0031] In the actual operation of traditional power plant check valves, when the valve is closed and the back pressure on the outlet side increases or frequent pressure fluctuations occur, the sealing force on the valve disc mainly comes from the valve disc's own weight, spring preload, and the medium pressure on the inlet side. The resultant force of these forces is basically constant. Therefore, once the outlet pressure exceeds the design expectation or fluctuates drastically, the original sealing force becomes relatively insufficient and cannot increase synchronously with the increase in back pressure. This results in the sealing pressure between the valve disc and the valve seat not being maintained at a reliable level, and small gaps easily form between the sealing surfaces. This problem of insufficient sealing force becomes more prominent, especially after long-term operation causes minor wear, erosion, or plastic deformation of the sealing surfaces. This leads to backflow of high-pressure fluid, causing serious hidden dangers such as valve not closing tightly and frequent internal leakage, directly affecting the isolation reliability of the power plant's steam-water system and the safe and economical operation of the unit. To solve this problem, this invention incorporates the following design in a power plant check valve that utilizes its own medium pressure for assisted sealing:

[0032] A power plant check valve utilizing its own medium pressure for assisted sealing includes: a power plant check valve body 1; a check valve flow block 2 fixedly connected inside the power plant check valve body 1; a check valve flow groove 3 formed inside the check valve flow groove 2; a movable block 4 slidably connected inside the check valve flow groove 3; a fixed block 5 fixedly connected inside the movable block 4; a connecting column 6 fixedly connected to the top of the fixed block 5; a support spring 7 fixedly connected to the top of the connecting column 6; a small corrugated structure 8 fixedly connected to the bottom of the movable block 4; and a large corrugated structure 9 fixedly connected to the bottom of the small corrugated structure 8. The bottom of the large corrugated structure 9 is fixedly connected to a corrugated base plate 10. The bottom of the fixed block 5 is fixedly connected to a telescopic rod structure 11. The outer wall of the telescopic rod structure 11 is slidably connected to a movable ring 12. The side of the movable ring 12 is fixedly connected to a limit cover 13. The inside of the limit cover 13 is slidably connected to a connecting rod 14. One end of the connecting rod 14 is fixedly connected to a support rod 15. The other end of the connecting rod 14 is fixedly connected to a sliding ball 16. The bottom of the telescopic rod structure 11 is fixedly connected to a fixed inclined block 18. Both the fixed inclined block 18 and the telescopic rod structure 11 have limit grooves 19 inside.

[0033] The support spring 7 is fixedly connected to the power station check valve body 1, and the support spring 7 provides elastic support. The movable block 4 and the fixed block 5 are connected by a connecting block. A hollow groove is provided between the movable block 4 and the fixed block 5. When the movable ring 12 moves down to the position of the fixed inclined block 18, the support rod 15 moves radially outward under the action of the inclined surface of the fixed inclined block 18, and completes the outward expansion in conjunction with the limiting slide groove 19. The outer wall of the large corrugated structure 9 is provided with a wear-resistant sealing layer. The wear-resistant sealing layer is made of polytetrafluoroethylene (PTFE). PTFE is a high-performance engineering plastic. As a wear-resistant sealing layer material, it has an extremely low coefficient of friction and excellent self-lubricating properties. When the large corrugated structure repeatedly expands and contracts, it effectively reduces the scraping resistance with the inner wall of the flow channel. At the same time, it has excellent chemical inertness and is resistant to almost all chemical media. The material is corroded, and under pressure, it can also generate a small amount of cold flow deformation, effectively filling the micro-unevenness of the sealing surface, thereby achieving excellent sealing effect. The support rod 15 is fixedly connected to the large corrugated structure 9. The support rod 15 is located in the middle of the large corrugated structure 9. The support rod 15 is arc-shaped. There are four support rods 15 at equal angles with respect to the vertical central axis of the telescopic rod structure 11. The fixed inclined block 18 is triangular. There are four fixed inclined blocks 18 at equal angles with respect to the vertical central axis of the telescopic rod structure 11. The sliding ball 16 is slidably connected to the limiting slide groove 19. There are four limiting slide grooves 19 at equal angles with respect to the vertical central axis of the telescopic rod structure 11. The bottom of the movable ring 12 is fixedly connected to the fixed rod 17. The fixed rod 17 is fixedly connected to the corrugated structure base plate 10.

[0034] When the device is in use, the power plant check valve body 1 operates normally. Liquid enters from the left side of the power plant check valve body 1, and the pressure on the left side begins to rise. Under the pressure, the corrugated base plate 10 moves upward. The corrugated base plate 10 drives the movable ring 12 to move upward together through the fixed rod 17. The upward movement of the movable ring 12 drives the limit cover 13, connecting rod 14, support rod 15, and sliding ball 16 to move upward. Since the sliding ball 16 is located in the limit groove 19, it causes the support rod 15 to retract when it moves upward. Under the action of the small corrugated structure 8 and the telescopic rod structure 11, the corrugated structure completely enters the movable block 4. At this time, the pressure continues to rise, and the pressure pushes the movable block 4 upward until the liquid can pass through the check valve. The liquid flows out from the right side of the flow channel 3. When the power station check valve body 1 is in the closed state, the movable block 4 is pushed back to the initial position under the elastic action of the support spring 7. At this time, the pressure on the right side begins to increase. The liquid enters the small corrugated structure 8 from the right side of the check valve flow channel 3, generating pressure to push the corrugated structure bottom plate 10 downward. The small corrugated structure 8 and the large corrugated structure 9 begin to expand. The movable ring 12 moves downward on the outer wall of the telescopic rod structure 11. When it passes the fixed inclined block 18, it pushes the support rod 15 to expand outward. At this time, the large corrugated structure 9 begins to expand until it fits against the inner wall of the check valve flow channel 3. The liquid pressure of the large corrugated structure 9 causes it to expand, making the fit tighter and the sealing performance higher.

[0035] Equipped with a corrugated structure, when the valve is opened in the forward direction, the inlet pressure on the left side pushes the corrugated structure base plate 10 upward. The fixed rod 17 and the movable ring 12 drive the support rod 15 to retract along the trajectory of the limiting slide groove 19, causing the entire corrugated structure to retract into the movable block 4. When the valve is closed and the back pressure on the right side increases, the high-pressure liquid enters the inner cavity of the small corrugated structure 8 in the reverse direction, driving the corrugated structure base plate 10 to move in the reverse direction, thereby pushing the movable ring 12 downward. When passing the fixed inclined block 18, it forces the support rod 15 to expand outward, opening the large corrugated structure 9 until it is tightly fitted with the inner wall of the check valve flow groove 3. At this time, the higher the pressure on the right side, the greater the liquid pressure acting on the large corrugated structure 9, making it expand and fit more tightly, thus achieving a self-tightening sealing effect where the sealing force increases synchronously with the back pressure.

[0036] By constructing a corrugated structure directly driven by the back pressure on the outlet side, the large corrugated structure 9 actively expands radially under the action of reverse pressure and tightly fits the inner wall of the check valve's flow groove 3, achieving a self-tightening sealing effect where the sealing force increases synchronously with the back pressure. This fundamentally solves the technical problem of internal leakage caused by insufficient sealing force in traditional check valves under high pressure or pressure fluctuation conditions. It significantly improves the sealing reliability and pressure bearing capacity of the valve in the closed state, and has the advantages of compact structure, sensitive response, and long service life. It is especially suitable for the harsh working conditions of high temperature and high pressure critical systems such as power plant feedwater and steam extraction.

[0037] The technical scope of this invention is not limited to the content described above. Those skilled in the art can make various modifications and variations to the above embodiments without departing from the technical concept of this invention, and all such modifications and variations should fall within the protection scope of this invention.

Claims

1. A power plant check valve that utilizes its own medium pressure for assisted sealing, characterized in that, include: The power plant check valve body includes a check valve flow block fixedly connected inside. The check valve flow block has a check valve flow groove inside. A movable block is slidably connected inside the check valve flow groove. A fixed block is fixedly connected inside the movable block. A connecting column is fixedly connected to the top of the fixed block. A support spring is fixedly connected to the top of the connecting column. A small corrugated structure is fixedly connected to the bottom of the movable block. A large corrugated structure is fixedly connected to the bottom of the small corrugated structure. A corrugated base plate is fixedly connected to the bottom of the large corrugated structure. A telescopic rod structure is fixedly connected to the bottom of the fixed block. A movable ring is slidably connected to the outer wall of the telescopic rod structure. A limit cover is fixedly connected to the side of the movable ring. A connecting rod is slidably connected inside the limit cover. A support rod is fixedly connected to one end of the connecting rod. A sliding ball is fixedly connected to the other end of the connecting rod. A fixed inclined block is fixedly connected to the bottom of the telescopic rod structure. Limit grooves are provided inside both the fixed inclined block and the telescopic rod structure.

2. The power plant check valve using its own medium pressure to assist in sealing according to claim 1, characterized in that: The support spring is fixedly connected to the power station check valve body, and the support spring provides elastic support.

3. The power plant check valve using its own medium pressure to assist in sealing according to claim 1, characterized in that: The movable block and the fixed block are connected by a connecting block, and a hollow groove is provided between the movable block and the fixed block.

4. The power plant check valve using its own medium pressure to assist in sealing according to claim 1, characterized in that: When the movable ring moves down to the position of the fixed inclined block, the support rod moves radially outward under the action of the inclined surface of the fixed inclined block, and completes the outward expansion in conjunction with the limiting slide groove.

5. The power plant check valve using its own medium pressure to assist in sealing according to claim 1, characterized in that: The outer wall of the large corrugated structure is provided with a wear-resistant sealing layer, which is made of polytetrafluoroethylene.

6. The power plant check valve using its own medium pressure to assist in sealing according to claim 1, characterized in that: The support rod is fixedly connected to the large corrugated structure, and the support rod is located in the middle of the large corrugated structure.

7. The power plant check valve using its own medium pressure to assist in sealing according to claim 1, characterized in that: The support rod is arc-shaped, and four support rods are arranged at equal angles about the vertical central axis of the telescopic rod structure.

8. The power plant check valve using its own medium pressure to assist in sealing according to claim 1, characterized in that: The fixed inclined blocks are arranged in a triangular shape, and four fixed inclined blocks are arranged at equal angles about the vertical central axis of the telescopic rod structure.

9. The power plant check valve using its own medium pressure to assist in sealing according to claim 1, characterized in that: The sliding ball and the limiting groove are slidably connected, and the limiting groove is provided at equal angles about the vertical central axis of the telescopic rod structure.

10. The power plant check valve using its own medium pressure to assist in sealing according to claim 1, characterized in that: The bottom of the movable ring is fixedly connected to a fixing rod, and the fixing rod is fixedly connected to the corrugated base plate.

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