Water turbine water inlet ball valve and overhauling sealing flat pressing quitting method

Abstract

The invention discloses a water turbine water inlet ball valve and a maintenance seal flat pressing quitting method, and belongs to the technical field of ball valve sealing.The maintenance seal flat pressing quitting method comprises the following steps that a, a working seal is controlled to be switched to an input position, so that an inner cavity of a valve body of the water inlet ball valve and a downstream water diversion pipe are in a disconnected state; a closed pressure-bearing cavity is formed in the inner cavity of the valve body; b, a flat pressing pipeline is arranged between the valve body and the upstream water diversion pipe, upstream water pressure is introduced into an inner cavity of the valve body through the flat pressing pipeline, and the water pressure of the inner cavity of the valve body is equal to the upstream water pressure; and c, controlling the pressure of an overhaul exit cavity of the overhaul seal to be greater than that of the overhaul input cavity, so that an overhaul movable ring of the overhaul seal is switched to an exit position from an input position, and flat pressing exit of the overhaul seal is completed. The invention effectively solves the technical problem of insufficient reliability of overhaul seal exit, and has the advantages of safety, reliability and high efficiency.

Description

Technical Field

[0001] The invention belongs to the technical field of ball valve sealing, and in particular relates to a turbine water inlet ball valve and a sealing flat pressure withdrawal method for maintenance. Background Art

[0002] At present, high-head pumps / turbines mostly use penstocks to divert water to connect the upstream reservoir with the pump and turbine. Between the penstock of each unit and the inlet of the unit volute, near the volute side of the unit, there is an inlet ball valve to cut off the water flow when needed. A maintenance seal is set on the upstream side of the inlet ball valve and a working seal is set on the downstream side. During normal start-up and shutdown, the working seal participates in the control, while the maintenance seal is only manually engaged during maintenance. The function of the inlet ball valve maintenance seal is to inspect the working seal of the inlet ball valve and the equipment and facilities on the downstream side of the flow channel without draining the water from the penstock. However, given that the water pressure of the inlet ball valve of a high-head power station is usually above 5MPa, there are major safety hazards when only the maintenance seal is engaged to overhaul the downstream flow channel and equipment. Therefore, the maintenance seal is designed to have a self-locking function to prevent opening due to misoperation.

[0003] At present, there are many maintenance sealing technologies involving self-locking functions in water inlet ball valves. For example, Chinese patent document with announcement number CN107859755B discloses a ball valve maintenance seal control method. This method realizes effective sealing between a movable sealing ring and a fixed sealing ring by designing the pressure action area of ​​the maintenance seal opening cavity, thereby constructing a self-locking maintenance seal. Even when the maintenance seal opening cavity is fed with upstream water pressure, since the water pressure on the upstream side of the movable sealing ring is still greater than the water pressure on the downstream side, the resultant force on the movable sealing ring after water is passed through the opening cavity still points to the injection direction. This method can also effectively prevent the occurrence of misoperation and has a good self-locking function.

[0004] Usually, the above-mentioned ball valve needs to introduce a bypass line when performing the seal withdrawal operation for maintenance. Figure 2-4As shown, the bypass pipeline includes a bypass pipe 17, one end of which is connected to the upstream water pipe 5, and the other end of the bypass pipe 17 is connected to the downstream water pipe 8. The downstream water pipe 8 is connected with a water guide volute 20, and the bypass pipe 17 is provided with two bypass valves including a maintenance bypass valve 18 and a working bypass valve 19. The maintenance bypass valve 18 is kept in a normally open state. When it is necessary to switch the maintenance seal at A from the input position to the withdrawal position, all movable guide vanes in the water guide volute 20 are first closed to achieve the condition of water blocking and pressure maintenance. At the same time, the working seal at B is controlled to switch from the input state to the withdrawal state, so that the valve body 1 forms a connected closed cavity with the downstream water pipe 8 and the water guide volute 20, and then the working bypass valve 19 is opened, and water is filled into the downstream side of the water inlet ball valve through the bypass pipe 17. The upstream pressure water flowing through the bypass pipe 17 passes through the working movable ring 6. The gap with the valve 2 enters the valve body 1, acts on the end face of the maintenance movable ring 3 connected to the valve body 1, and balances a part of the input force of the maintenance movable ring 3 and the upstream end face, thereby completing the pressure equalization of the upstream and downstream sides of the maintenance seal movable ring at A; at this time, the maintenance exit chamber 102 is controlled to introduce upstream water pressure, and the maintenance input chamber 101 is connected to drain water, and a gap will be generated between the maintenance movable ring 3 and the valve 2, and the upstream water pressure in the upstream water pipe 5 enters the valve body 1 through the gap, thereby achieving the purpose of exiting the maintenance seal. However, after careful analysis, it was found that it still has the following technical problems: Since adjacent movable guide vanes in the closed state rely on contact surface compression sealing, there is a potential risk of leakage. Once leakage occurs and the leakage accumulates to a certain extent, it will be difficult to construct an effective closed cavity, resulting in insufficient pressure on the downstream side of the maintenance movable ring to balance the pressure on the upstream side of the maintenance movable ring. Therefore, the reliability of the existing maintenance seal when exiting is still insufficient.

[0005] Therefore, it is urgent to explore a reliable maintenance seal withdrawal technology to ensure the safety and efficiency of production. Summary of the invention

[0006] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a turbine water inlet ball valve and a maintenance seal flat pressure withdrawal method, which effectively solves the technical problem of insufficient reliability of the existing maintenance seal withdrawal, ensures the effective withdrawal of the maintenance seal, and further ensures the safety and efficiency of production.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows: On the one hand, the present invention provides a turbine water inlet ball valve, comprising a valve body and a smoothing pipeline, the water inlet end of the valve body is connected to an upstream water diversion pipe, the water outlet end of the valve body is connected to a downstream water diversion pipe, a maintenance seal and a working seal are respectively provided in the valve body, and a sand discharge pipe communicating with the inner cavity of the valve body is provided at the lower part of the valve body; one end of the smoothing pipeline is connected to the upstream water diversion pipe, and the other end is connected to the inner cavity of the valve body through the sand discharge pipe, and the smoothing pipeline is used to control the upstream water diversion pipe to be connected to the inner cavity of the valve body for smoothing when exiting the maintenance seal.

[0008] Preferably, the equalizing pressure pipeline includes a equalizing pressure main pipe and a equalizing pressure isolating valve, one end of the equalizing pressure main pipe is connected to the upstream water diversion pipe, and the other end of the equalizing pressure main pipe is connected to the valve body through the sand discharge pipe, and the equalizing pressure isolating valve includes a first equalizing pressure isolating valve, a equalizing pressure switch control valve and a second equalizing pressure isolating valve which are sequentially arranged on the equalizing pressure main pipe, the first equalizing pressure isolating valve is used to isolate the water pressure of the upstream water diversion pipe, and the second equalizing pressure isolating valve is used to isolate the water pressure of the inner cavity of the valve body, and the equalizing pressure main pipe controls the connection and disconnection of the upstream water diversion pipe and the inner cavity of the valve body through the equalizing pressure switch control valve, the first equalizing pressure isolating valve and the second equalizing pressure isolating valve.

[0009] Preferably, a sand discharge valve is provided on the sand discharge pipe, the first equalizing pressure isolating valve is located at one end close to the upstream water diversion pipe, and the second equalizing pressure isolating valve is located between the valve body and the sand discharge valve.

[0010] Preferably, the downstream water diversion pipe is a downstream expansion joint.

[0011] On the other hand, the present invention provides a method for inspecting and sealing a water turbine inlet ball valve by flat pressure withdrawal, comprising the following steps: a. Control the working seal to switch to the input position, so that the inner cavity of the water inlet ball valve is disconnected from the downstream water diversion pipe, and the inner cavity of the valve body forms a closed pressure-bearing cavity; b. A pressure-equalizing pipeline is installed between the valve body and the upstream water diversion pipe, and the upstream water pressure is introduced into the inner cavity of the valve body by means of the pressure-equalizing pipeline, so that the water pressure in the inner cavity of the valve body is equal to the upstream water pressure; c. Control the pressure of the maintenance withdrawal chamber of the maintenance seal to be greater than the pressure of the maintenance insertion chamber, so that the maintenance movable ring of the maintenance seal is switched from the insertion position to the withdrawal position, completing the flat pressure withdrawal of the maintenance seal.

[0012] Preferably, the equalizing pressure pipeline includes a equalizing pressure main pipe and a equalizing pressure isolating valve, one end of the equalizing pressure main pipe is connected to the upstream water diversion pipe, and the other end of the equalizing pressure main pipe is connected to the sand discharge pipe; the equalizing pressure isolating valve includes a first equalizing pressure isolating valve, a equalizing pressure switch control valve and a second equalizing pressure isolating valve which are sequentially arranged on the equalizing pressure main pipe; a sand discharge pipe which communicates with the inner cavity of the valve body is provided at the lower part of the valve body, a sand discharge valve is provided on the sand discharge pipe, the first equalizing pressure isolating valve is located near one end of the upstream water diversion pipe, and the second equalizing pressure isolating valve is located between the valve body and the sand discharge valve.

[0013] Preferably, in step b, the method of introducing the upstream water pressure into the valve body by using the equalizing pressure pipeline is as follows: first control the first equalizing pressure isolating valve and the second equalizing pressure isolating valve to open, so that the upstream water diversion pipe and the valve body are connected to the equalizing pressure main pipe respectively; then control the equalizing pressure switch control valve to open, so that the upstream water diversion pipe is connected to the valve body, so as to achieve equal water pressure between the upstream water diversion pipe and the water inlet ball valve body.

[0014] Preferably, in step a, the method for controlling the working seal to switch to the injection position is: the working injection chamber of the working seal introduces upstream water pressure to build up pressure, and the working withdrawal chamber is connected to drain water to lose pressure, so that the working seal switches from the withdrawal position to the injection position.

[0015] Preferably, in step c, the method for controlling the pressure of the maintenance exit chamber in the maintenance seal to be greater than the pressure of the maintenance input chamber is: introducing upstream water pressure into the maintenance exit chamber to build up pressure, and connecting the maintenance input chamber to drain water to lose pressure, so that the maintenance movable ring of the maintenance seal is switched from the input position to the exit position.

[0016] The advantages of adopting the present invention are: 1. The water turbine water inlet ball valve of the present invention, firstly, realizes the connection between the water inlet ball valve body and the upstream water diversion pipe by setting a pressure-equalizing pipeline between the upstream water diversion pipe and the valve body, so that the water pressure of the upstream water diversion pipe can be smoothly introduced into the inner cavity of the valve body, thereby quickly achieving the water pressure balance between the inner cavity of the valve body and the upstream water diversion pipe. This design not only avoids the leakage risk that may occur after the adjacent movable guide vanes are closed in the prior art, but also effectively solves the problem of insufficient reliability of the maintenance seal withdrawal caused by potential leakage. Therefore, the maintenance seal can be smoothly withdrawn under safer and more reliable conditions, ensuring the stability and safety of the operation of the entire unit.

[0017] Secondly, by respectively arranging the inspection seal and the working seal in the valve body, it can be ensured that during the inspection process, the inspection seal can effectively isolate the water flow of the downstream water pipe, while the working seal and the equipment and facilities on the downstream side of the flow channel can be inspected without draining the water from the upstream water pipe, thereby greatly improving the convenience and safety of the inspection work.

[0018] Third, by providing a sand discharge valve connected to the inner cavity of the valve body, sand and impurities in the valve body can be discharged regularly to prevent sand and other impurities from causing wear or blockage to the inside of the valve body, thereby extending the service life of the valve body and ensuring the normal operation of the turbine water inlet ball valve.

[0019] 2. The turbine water inlet ball valve in the present invention forms isolation by installing the first equalizing pressure isolating valve and the second equalizing pressure isolating valve on the equalizing pressure main pipe. This design not only effectively isolates the pressurized water in the upstream water diversion pipe and the water inlet ball valve body respectively, but also significantly reduces the risk of leakage and uncontrolled spraying of pressurized water due to accidental damage to the equalizing pressure main pipe. At the same time, it significantly simplifies the isolation measures for the maintenance of the equalizing pressure pipe. It is only necessary to close the first equalizing pressure isolating valve and the second equalizing pressure isolating valve to form isolation without draining the upstream water diversion pipe. Moreover, when it is necessary to balance the pressure between the upstream water diversion pipe and the water inlet ball valve, the operation process is also very convenient: first, open the first equalizing pressure isolating valve and the second equalizing pressure isolating valve to release the isolation of the pressurized water between the equalizing pressure main pipe and the upstream water diversion pipe and the water inlet ball valve body, and then open the equalizing pressure switch control valve, so that the risk of damage to the equalizing pressure main pipe under pressure is greatly reduced. At the same time, the equalizing pressure switch control valve can be installed in a position that is convenient for operation, and the equalizing pressure operation is also more convenient. After the maintenance seal is smoothly switched to the exit position, it is no longer necessary to use the equalization pressure main pipe to draw water and introduce the upstream water pressure into the water inlet ball valve body for equalization. Therefore, the first equalization pressure isolation valve, equalization pressure switch control valve and second equalization pressure isolation valve on the equalization pressure main pipe can be closed to keep the equalization pressure main pipe in a pressure-free state, reduce the risk of pipeline damage under pressure, and improve the safe operation level of the unit. In addition, the setting of the equalization pressure isolation valve allows the connection and disconnection between the upstream water diversion pipe and the valve body to be flexibly controlled, which not only provides convenience for maintenance operations, but also improves the flexibility and maintainability of the entire turbine water inlet ball valve system.

[0020] Under this design, the present invention controls the opening of the equalizing pressure isolating valve, and the water inlet ball valve body and the upstream water diversion pipe together form a connected cavity, providing sufficient pressure for the downstream side of the maintenance seal movable ring to balance the input force on its upstream side, thereby providing a solid and reliable guarantee for the smooth withdrawal of the maintenance seal.

[0021] 3. The method for withdrawing the turbine water inlet ball valve maintenance seal under flat pressure in the present invention first controls the working seal to switch to the engaged position, so that the inner cavity of the valve body of the water inlet ball valve and the downstream water diversion pipe are disconnected, and the inner cavity of the valve body forms a closed pressure-bearing cavity, so that all pipelines that may affect the pressure state of the water inlet ball valve body are effectively controlled, ensuring that all functional pipelines such as drainage, exhaust, and sand discharge that may affect the pressure state of the water inlet ball valve body are effectively controlled, creating conditions for the smooth withdrawal of the maintenance seal.

[0022] Secondly, compared with the prior art, the method proposed by the present invention has achieved significant improvements in the maintenance seal withdrawal mechanism. It abandons the traditional practice, that is, it no longer relies on first introducing the upstream water pressure into the inner cavity of the downstream water diversion pipe through the bypass valve, then closing the movable guide vane, and switching the working seal to the withdrawal state, so as to connect the valve body of the water inlet ball valve with the inner cavity of the downstream water diversion pipe to form a closed cavity, and then use the bypass pipe control to achieve the pressure equalization between the closed cavity and the upstream side of the maintenance seal, so as to complete the withdrawal of the maintenance seal movable ring.

[0023] On the contrary, the present method controls the working seal to switch to the insertion position, and forms a closed pressure-bearing cavity in the inner cavity of the valve body, and further sets a pressure-equalizing pipeline between the valve body and the upstream water diversion pipe, so that the valve body and the upstream water diversion pipe form a connected cavity together. Subsequently, by controlling the pressure of the maintenance withdrawal cavity in the maintenance seal to be greater than the maintenance insertion cavity, a gap will be generated between the maintenance movable ring of the maintenance seal and the valve, and the upstream water pressure can enter the closed pressure-bearing cavity of the water inlet ball valve body formed before through this gap. This process is essentially to guide the pressure in the upstream water diversion pipe into the water inlet ball valve body, so that the water pressure acts on the effective area of ​​the movable ring of the maintenance seal, thereby balancing a part of the water pressure acting on the effective area of ​​the maintenance movable ring of the maintenance seal. In this way, the maintenance movable ring can smoothly overcome the resistance during the withdrawal movement, realize the pressure equalization of the upstream and downstream sides of the self-locking maintenance seal, and then the maintenance movable ring of the maintenance seal can be smoothly switched to the withdrawal position.

[0024] In summary, the method for flat-pressure withdrawal of the maintenance seal of a water turbine inlet ball valve of the present invention effectively solves the technical problem of insufficient reliability of withdrawal of the maintenance seal, ensures effective withdrawal of the maintenance seal, and further guarantees safety and efficiency of production.

[0025] 4. The method for withdrawing the maintenance seal of the water turbine inlet ball valve under pressure in the present invention effectively introduces the water pressure of the upstream water diversion pipe into the valve body of the water inlet ball valve by accurately controlling the opening sequence of the first pressure-smoothing isolation valve, the second pressure-smoothing isolation valve and the pressure-smoothing switch control valve in the pressure-smoothing main pipe, and achieves balance with the upstream water pressure of the maintenance seal. This method improves the accuracy and efficiency of the pressure balancing process, ensures that the maintenance seal can be safely and reliably switched to the withdrawal position, and has the advantages of simple operation, significant effect and low maintenance cost.

[0026] 5. The method for withdrawing the maintenance seal of a turbine water inlet ball valve under flat pressure in the present invention, in step a, the upstream water pressure is introduced into the working injection chamber of the working seal to build up pressure, and the working withdrawal chamber is connected to drain and lose pressure, so that the working seal is accurately controlled to switch to the injection position, and the connection between the inner cavity of the valve body and the downstream water diversion pipe is effectively cut off, forming a closed pressure-bearing cavity, which lays a solid foundation for the subsequent pressure-smoothing withdrawal operation of the maintenance seal; and in step c, the upstream water pressure is introduced into the maintenance withdrawal chamber to build up pressure, and the maintenance injection chamber is connected to drain and lose pressure, so that the pressure of the maintenance withdrawal chamber of the maintenance seal is accurately controlled to be greater than the pressure of the maintenance injection chamber, thereby realizing the smooth switching of the maintenance movable ring of the maintenance seal from the injection position to the withdrawal position. This method not only improves the safety and reliability of the withdrawal of the maintenance seal, but also effectively avoids the potential risks caused by misoperation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 It is a schematic cross-sectional structure diagram of the water inlet ball valve in the present invention; Figure 2 It is a schematic diagram of the cross-sectional structure of a water inlet ball valve in the prior art; Figure 3 for Figure 2 The enlarged schematic diagram of the maintenance seal at A in the middle is in the put-in state; Figure 4 for Figure 2 An enlarged schematic diagram showing the working seal at B in the engaged state.

[0028] The numbers in the figure are: 1. valve body, 100. maintenance seal, 101. maintenance input chamber, 102. maintenance withdrawal chamber, 103. working withdrawal chamber, 104. working input chamber, 2. valve, 200. working seal, 3. maintenance movable ring, 300. equalizing pressure pipeline, 4. maintenance guide ring, 5. upstream water diversion pipe, 6. working movable ring, 7. working guide ring, 8. downstream water diversion pipe, 9. relay, 10. maintenance locking pin, 11. sand discharge valve, 12. equalizing pressure main pipe, 13. equalizing pressure switch control valve, 14. second equalizing pressure isolation valve, 15. first equalizing pressure isolation valve, 16. sand discharge pipe, 17. bypass pipe, 18. maintenance bypass valve, 19. working bypass valve, 20. water guide volute. DETAILED DESCRIPTION

[0029] To make the purpose, technical solution and advantages of the embodiments of the present invention more clear, the technical solution in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0030] Example 1 This embodiment provides a water turbine water inlet ball valve, such as Figure 1As shown, it includes a valve body 1. Further, the turbine water inlet ball valve also includes a pressure-equalizing pipeline 300. The water inlet end of the valve body 1 is connected to an upstream water diversion pipe 5, and the water outlet end of the valve body 1 is connected to a downstream water diversion pipe 8. The downstream water diversion pipe 8 is preferably a downstream expansion joint.

[0031] The valve body 1 is provided with a maintenance seal 100 and a working seal 200, and the lower part of the valve body 1 is also provided with a sand discharge pipe 16 communicating with the inner cavity of the valve body 1; one end of the equalization pressure pipeline 300 is connected to the upstream water diversion pipe 5, and the other end is connected to the inner cavity of the valve body 1 through the sand discharge pipe 16. The equalization pressure pipeline 300 is used to control the upstream water diversion pipe 5 to communicate with the inner cavity of the valve body 1 for equalization when the maintenance seal 100 is exited. It should be noted that in some embodiments, the other end of the equalization pressure pipeline 300 can also selectively communicate with the inner cavity of the valve body 1 through other reserved openings on the valve body 1 to achieve the purpose of equalization.

[0032] In this embodiment, by setting a pressure-equalizing pipeline between the upstream water diversion pipeline and the valve body, the connection between the water inlet ball valve body and the upstream water diversion pipe is achieved, so that the water pressure of the upstream water diversion pipe can be smoothly introduced into the inner cavity of the valve body, thereby quickly achieving water pressure balance between the inner cavity of the valve body and the upstream water diversion pipe. This design not only avoids the leakage risk that may occur after the adjacent movable guide vanes are closed in the prior art, but also effectively solves the problem of insufficient reliability of the maintenance seal withdrawal caused by potential leakage. Therefore, the maintenance seal can be smoothly withdrawn under safer and more reliable conditions, ensuring the stability and safety of the entire unit operation.

[0033] The equalizing pressure pipeline 300 includes an equalizing pressure main pipe 12 and an equalizing pressure isolation valve. One end of the equalizing pressure main pipe 12 is connected to the upstream water diversion pipe 5 , and the other end of the equalizing pressure main pipe 12 is connected to the sand discharge pipe 16 .

[0034] The equalizing pressure isolating valve comprises a first equalizing pressure isolating valve 15, a equalizing pressure switch control valve 13 and a second equalizing pressure isolating valve 14 which are sequentially arranged on the equalizing pressure main pipe 12. The first equalizing pressure isolating valve 15 is used to isolate the water pressure of the upstream water diversion pipe 5, and the second equalizing pressure isolating valve 14 is used to isolate the water pressure in the inner cavity of the valve body 1. The equalizing pressure main pipe 12 controls the connection and disconnection between the upstream water diversion pipe 5 and the inner cavity of the valve body 1 through the equalizing pressure switch control valve 13, the first equalizing pressure isolating valve 15 and the second equalizing pressure isolating valve 14.

[0035] Furthermore, a sand discharge valve 11 is provided on the sand discharge pipe 16 , a first equalizing pressure isolating valve 15 is located at one end close to the upstream water diversion pipe 5 , and a second equalizing pressure isolating valve 14 is located between the valve body 1 and the sand discharge valve 11 .

[0036] In this embodiment, isolation is formed by installing the first pressure-scaling isolation valve 15 and the second pressure-scaling isolation valve 14 on the pressure-scaling main pipe 12. This design not only effectively isolates the pressurized water in the upstream water diversion pipe 5 and the water inlet ball valve body 1 respectively, but also significantly reduces the risk of leakage and uncontrolled spraying of pressurized water due to accidental damage to the pressure-scaling main pipe. At the same time, it significantly simplifies the isolation measures for the maintenance of the pressure-scaling pipe. It is only necessary to close the first pressure-scaling isolation valve and the second pressure-scaling isolation valve to form isolation without draining the upstream water diversion pipe. Moreover, when it is necessary to balance the pressure between the upstream water diversion pipe 5 and the water inlet ball valve, the operation process is also very convenient: first, open the first pressure-scaling isolation valve 15 and the second pressure-scaling isolation valve 14 to release the pressure water isolation between the pressure-scaling main pipe 12 and the upstream water diversion pipe 5 and the water inlet ball valve body 1, and then open the pressure-scaling switch control valve 13, so that the risk of damage to the pressure-scaling main pipe 12 under pressure operation is greatly reduced. At the same time, the pressure-scaling switch control valve can be installed in a position that is convenient for operation, making the pressure-scaling operation more convenient.

[0037] After the maintenance seal 100 is successfully switched to the exit position, the equalizing pressure main pipe 12 is no longer needed to draw water to introduce the upstream water pressure into the water inlet ball valve body 1 for equalizing pressure. Therefore, the first equalizing pressure isolation valve 15, the equalizing pressure switch control valve 13 and the second equalizing pressure isolation valve 14 on the equalizing pressure main pipe 12 can be closed to keep the equalizing pressure main pipe 12 in a pressure-free state, reduce the risk of damage to the equalizing pressure main pipe under pressure, and improve the safe operation level of the unit.

[0038] In this embodiment, by controlling the opening of the equalizing pressure isolating valve, the water inlet ball valve body 1 and the upstream water diversion pipe 5 together form a connected cavity, providing sufficient pressure for the downstream side of the maintenance seal to balance the pressure on its upstream side, thereby providing a solid and reliable guarantee for the smooth exit of the maintenance seal.

[0039] Example 2 This embodiment provides a method for inspecting and sealing a water turbine inlet ball valve and performing flat pressure withdrawal, which can be implemented by a water turbine inlet ball valve in Embodiment 1, and includes the following steps: a. Control the working seal 200 to switch to the input position, so that the inner cavity of the valve body 1 of the water inlet ball valve is disconnected from the downstream water diversion pipe 8, and the inner cavity of the valve body 1 forms a closed pressure-bearing cavity; In step a, it should be noted that in order to form a closed pressure-bearing cavity in the inner cavity of the valve body 1, it is necessary to close all pipelines that release pressure, including the sand discharge pipe 16, so that all pipelines that may affect the pressure state of the water inlet ball valve body 1 are effectively controlled, creating conditions for the smooth exit of the maintenance seal 100.

[0040] b. A pressure-equalizing pipeline 300 is provided between the valve body 1 and the upstream water diversion pipe 5, and the upstream water pressure is introduced into the inner cavity of the valve body 1 by means of the pressure-equalizing pipeline 300, so that the water pressure in the inner cavity of the valve body 1 is equal to the upstream water pressure; c. Control the pressure of the maintenance withdrawal chamber 102 of the maintenance seal 100 to be greater than the pressure of the maintenance input chamber 101, so that the maintenance movable ring 3 of the maintenance seal 100 is switched from the input position to the withdrawal position, and the flat pressure withdrawal of the maintenance seal 100 is completed.

[0041] This embodiment is the most basic implementation method, "a. Control the working seal 200 to switch to the input position, so that the inner cavity of the valve body 1 of the water inlet ball valve is in a disconnected state with the downstream water diversion pipe 8, and the inner cavity of the valve body 1 forms a closed pressure-bearing cavity; b. Set a pressure-equalizing pipeline 300 between the valve body 1 and the upstream water diversion pipe 5, and use the pressure-equalizing pipeline 300 to introduce the upstream water pressure into the inner cavity of the valve body 1, so that the water pressure in the inner cavity of the valve body 1 is equal to the upstream water pressure; c. Control the pressure of the maintenance withdrawal cavity 102 of the maintenance seal 100 to be greater than the pressure of the maintenance input cavity 101, so that the maintenance movable ring 3 of the maintenance seal 100 is switched from the input position to the withdrawal position, and the pressure-equalizing withdrawal of the maintenance seal 100 is completed". As a complete technical solution, compared with the prior art, this method controls the working seal to switch to the input position, and forms a closed pressure-bearing cavity in the inner cavity of the valve body 1, and further sets a pressure-equalizing pipeline between the valve body 1 and the upstream water diversion pipe 5, so that the valve body 1 and the upstream water diversion pipe 5 form a connected cavity together. Subsequently, by controlling the pressure of the maintenance exit chamber 102 in the maintenance seal to be greater than the maintenance input chamber 101, a gap will be generated between the maintenance movable ring 3 of the maintenance seal and the valve 2, and the upstream water pressure can enter the previously formed closed pressure-bearing cavity of the water inlet ball valve body 1 through this gap. This process essentially guides the pressure in the upstream water diversion pipe 5 into the water inlet ball valve body 1, so that the water pressure acts on the effective area of ​​the movable ring 3 of the maintenance seal, thereby balancing a part of the water pressure acting on the effective area of ​​the maintenance movable ring 3 of the maintenance seal by the upstream water pressure. In this way, the maintenance movable ring 3 can smoothly overcome the resistance during the withdrawal movement, realize the equalization of the upstream and downstream sides of the self-locking maintenance seal, and then smoothly switch the maintenance movable ring 3 of the maintenance seal to the withdrawal position.

[0042] Example 3 This embodiment provides a method for inspecting and sealing a water turbine inlet ball valve and performing flat pressure withdrawal, which can be implemented by a water turbine inlet ball valve in Embodiment 1, and includes the following steps: a. Control the working seal 200 to switch to the input position, so that the inner cavity of the valve body 1 of the water inlet ball valve is disconnected from the downstream water diversion pipe 8, and the inner cavity of the valve body 1 forms a closed pressure-bearing cavity; In step a, it should be noted that in order to form a closed pressure-bearing cavity in the inner cavity of the valve body 1, it is necessary to close all pipelines that release pressure, including the sand discharge pipe 16, so that all pipelines that may affect the pressure state of the water inlet ball valve body 1 are effectively controlled, creating conditions for the smooth exit of the maintenance seal 100.

[0043] b. A pressure-equalizing pipeline 300 is provided between the valve body 1 and the upstream water diversion pipe 5, and the upstream water pressure is introduced into the inner cavity of the valve body 1 by means of the pressure-equalizing pipeline 300, so that the water pressure in the inner cavity of the valve body 1 is equal to the upstream water pressure; c. Control the pressure of the maintenance withdrawal chamber 102 of the maintenance seal 100 to be greater than the pressure of the maintenance input chamber 101, so that the maintenance movable ring 3 of the maintenance seal 100 is switched from the input position to the withdrawal position, and the flat pressure withdrawal of the maintenance seal 100 is completed.

[0044] The equalizing pressure pipeline 300 includes a equalizing pressure main pipe 12 and a equalizing pressure isolating valve, one end of the equalizing pressure main pipe 12 is connected to the upstream water diversion pipe 5, and the other end of the equalizing pressure main pipe 12 is connected to the sand discharge pipe 16; the equalizing pressure isolating valve includes a first equalizing pressure isolating valve 15, a equalizing pressure switch control valve 13 and a second equalizing pressure isolating valve 14 which are sequentially arranged on the equalizing pressure main pipe 12; a sand discharge pipe 16 which communicates with the inner cavity of the valve body 1 is arranged at the lower part of the valve body 1, and a sand discharge valve 11 is arranged on the sand discharge pipe 16; the first equalizing pressure isolating valve 15 is located at one end close to the upstream water diversion pipe 5, and the second equalizing pressure isolating valve 14 is located between the valve body 1 and the sand discharge valve 11.

[0045] In step b, the method of introducing the upstream water pressure into the valve body 1 by using the equalizing pressure pipeline 300 is as follows: first, the first equalizing pressure isolating valve 15 and the second equalizing pressure isolating valve 14 are controlled to open, so that the upstream water diversion pipe 5 and the valve body 1 are connected to the equalizing pressure main pipe 12 respectively; then, the equalizing pressure switch control valve 13 is controlled to open, so that the upstream water diversion pipe 5 is connected to the valve body 1, so as to achieve equal water pressure between the upstream water diversion pipe 5 and the water inlet ball valve body 1.

[0046] This embodiment is a preferred implementation method. By accurately controlling the opening sequence of the first equalizing pressure isolation valve, the second equalizing pressure isolation valve and the equalizing pressure switch control valve in the equalizing pressure main pipe, the water pressure of the upstream water diversion pipe is effectively introduced into the valve body of the water inlet ball valve, and the balance with the upstream water pressure of the maintenance seal is achieved. This method improves the accuracy and efficiency of the pressure balancing process, ensures that the maintenance seal can be safely and reliably switched to the withdrawal position, and has the advantages of simple operation, significant effect and low maintenance cost.

[0047] Furthermore, a valve 2 is installed in the valve body 1 through a relay 9, and the working seal 200 includes a working movable ring 6 and a working guide ring 7. The working movable ring 6 is arranged in an annular cavity formed by the valve body 1 and the working guide ring 7. The working guide ring 7 and the working movable ring 6 form a working input cavity 104, and the valve body 1 and the working movable ring 6 form a working withdrawal cavity 103; in step a, the method of controlling the working seal 200 to switch to the input position is: the working input cavity 104 of the working seal 200 introduces upstream water pressure to build pressure, the working withdrawal cavity 103 is connected to drain and lose pressure, and the working movable ring 6 forms a seal with the valve 2 under the action of the downstream water pressure of the working seal 200, so that the working seal 200 switches from the withdrawal to the input position. At this time, the pressure value of the upstream water pressure of the upstream water diversion pipeline 5 acting on the effective area of ​​the upstream side of the maintenance movable ring 3 of the maintenance seal is equal to the pressure value of the valve body water pressure acting on the effective area of ​​the downstream side of the maintenance movable ring 3 of the maintenance seal.

[0048] Furthermore, the maintenance seal includes a maintenance movable ring 3 and a maintenance guide ring 4. The maintenance guide ring 4 of the maintenance seal can be locked with the maintenance movable ring 3 by a maintenance locking pin 10. The maintenance movable ring 3 is arranged in an annular cavity formed by the valve body 1 and the maintenance guide ring 4. The maintenance guide ring 4 and the maintenance movable ring 3 form a maintenance input cavity 101, and the valve body 1 and the maintenance movable ring 3 form a maintenance exit cavity 102. In step c, the method for controlling the pressure of the maintenance exit cavity 102 in the maintenance seal 100 to be greater than the pressure of the maintenance input cavity 101 is: the maintenance exit cavity 102 introduces upstream water pressure to build up pressure, and the maintenance input cavity 101 is connected to drain and lose pressure, so that the maintenance movable ring 3 of the maintenance seal 100 is switched from the input position to the exit position. At this time, the pressure value of the water pressure in the maintenance exit chamber 102 acting on the effective area of ​​the maintenance movable ring 3 of the maintenance seal is equal to the upstream water pressure in the upstream water pipe 5, and the pressure value of the water pressure in the maintenance input chamber 101 acting on the effective area of ​​the maintenance movable ring 3 is zero. Therefore, a resultant force toward the upstream side is formed on the maintenance movable ring 3, and the magnitude of the resultant force is equal to the upstream water pressure in the upstream water pipe 5 multiplied by the effective area of ​​the movable ring 3 acted by the water pressure in the maintenance input chamber 101 of the maintenance seal. Under the action of this part of the force, the movement resistance is overcome and the maintenance movable ring 3 of the maintenance seal moves to the upstream side and switches to the exit position.

[0049] The working input chamber 104, working withdrawal chamber 103 of the working seal 200, the maintenance input chamber 101 and maintenance withdrawal chamber 102 of the maintenance seal 100, each of which is connected to the upstream water pressure in the upstream water diversion pipe 5, is preferably realized by a two-position four-way valve. Through the two-position four-way valve, when the working seal 200 needs to be switched to be put in / out, the working input chamber 104 and the working withdrawal chamber 103 can be alternately connected to the upstream pressure water and connected to the atmosphere to discharge the pressure water; when the maintenance seal 100 needs to be switched to be put in / out, the maintenance input chamber 101 and the maintenance withdrawal chamber 102 of the maintenance seal 100 can also be alternately connected to the upstream pressure water and connected to the atmosphere to discharge the pressure water. This process belongs to the known technology in the art and will not be repeated here.

[0050] In this embodiment, in step a, the upstream water pressure is introduced to build up pressure through the working injection chamber 104 of the working seal 200, and the working withdrawal chamber 103 is connected to drain and lose pressure, so that the working seal is accurately controlled to switch to the injection position, and the connection between the inner cavity of the valve body 1 and the downstream water diversion pipe 8 is effectively cut off, forming a closed pressure-bearing cavity, which lays a solid foundation for the subsequent maintenance seal flat pressure withdrawal operation; and in step c, the upstream water pressure is introduced to build up pressure through the maintenance withdrawal chamber 102, and the maintenance injection chamber 101 is connected to drain and lose pressure, so that the pressure of the maintenance withdrawal chamber 102 of the maintenance seal is accurately controlled to be greater than the pressure of the maintenance injection chamber 101, thereby realizing the smooth switching of the maintenance movable ring 3 of the maintenance seal from the injection position to the withdrawal position. This method not only improves the safety and reliability of the withdrawal of the maintenance seal, but also effectively avoids the potential risks caused by misoperation.

[0051] It should be noted that the present invention Figure 1 In ( Figure 1 Taking the direction shown as an example), the state after the maintenance seal 100 and the working seal 200 are respectively put into use is indicated above the horizontal center line, at which time the valve 2 is closed and in a vertical state; the state after the working seal 200 is withdrawn is indicated below the horizontal center line, at which time the valve 2 is opened and in a horizontal state.

[0052] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A water turbine water inlet ball valve, comprising a valve body (1), characterized in that: It also comprises a pressure-equalizing pipeline (300), wherein the water inlet end of the valve body (1) is connected to an upstream water diversion pipe (5), the water outlet end of the valve body (1) is connected to a downstream water diversion pipe (8), a maintenance seal (100) and a working seal (200) are respectively provided in the valve body (1), and a sand discharge pipe (16) communicating with the inner cavity of the valve body (1) is provided at the lower part of the valve body (1); one end of the pressure-equalizing pipeline (300) is connected to the upstream water diversion pipe (5), and the other end is connected to the inner cavity of the valve body (1) through the sand discharge pipe (16), and the pressure-equalizing pipeline (300) is used to control the upstream water diversion pipe (5) to communicate with the inner cavity of the valve body (1) for pressure equalization when the maintenance seal (100) is withdrawn.

2. A water turbine water inlet ball valve according to claim 1, characterized in that: The pressure-equalizing pipeline (300) comprises a pressure-equalizing main pipe (12) and a pressure-equalizing isolation valve. One end of the pressure-equalizing main pipe (12) is connected to an upstream water diversion pipe (5), and the other end of the pressure-equalizing main pipe (12) is connected to a sand discharge pipe (16). The pressure-equalizing isolation valve comprises a first pressure-equalizing isolation valve (15), a pressure-equalizing switch control valve (13), and a second pressure-equalizing isolation valve (14) which are sequentially arranged on the pressure-equalizing main pipe (12). The first pressure-equalizing isolation valve (15) is used to isolate the water pressure of the upstream water diversion pipe (5), and the second pressure-equalizing isolation valve (14) is used to isolate the water pressure of the inner cavity of the valve body (1). The pressure-equalizing main pipe (12) controls the connection and disconnection between the upstream water diversion pipe (5) and the inner cavity of the valve body (1) through the pressure-equalizing switch control valve (13), the first pressure-equalizing isolation valve (15), and the second pressure-equalizing isolation valve (14).

3. A water turbine water inlet ball valve according to claim 2, characterized in that: The sand discharge pipe (16) is provided with a sand discharge valve (11), the first pressure-equalizing isolation valve (15) is located at one end close to the upstream water diversion pipe (5), and the second pressure-equalizing isolation valve (14) is located between the valve body (1) and the sand discharge valve (11).

4. A water turbine water inlet ball valve according to claim 1, characterized in that: The downstream water diversion pipe (8) is a downstream expansion joint.

5. A method for sealing and withdrawing a water turbine inlet ball valve during maintenance, characterized in that: The following steps are involved: a. Controlling the working seal (200) to switch to the engaged position, so that the inner cavity of the valve body (1) of the water inlet ball valve and the downstream water diversion pipe (8) are disconnected, and the inner cavity of the valve body (1) forms a closed pressure-bearing cavity; b. a pressure-equalizing pipeline (300) is provided between the valve body (1) and the upstream water diversion pipe (5), and the upstream water pressure is introduced into the inner cavity of the valve body (1) by means of the pressure-equalizing pipeline (300), so that the water pressure in the inner cavity of the valve body (1) is equal to the upstream water pressure; c. Control the pressure of the maintenance withdrawal chamber (102) of the maintenance seal (100) to be greater than the pressure of the maintenance insertion chamber (101), so that the maintenance movable ring (3) of the maintenance seal (100) is switched from the insertion position to the withdrawal position, thereby completing the flat pressure withdrawal of the maintenance seal (100).

6. A method for sealing and flat-pressing withdrawal of a water turbine inlet ball valve for inspection and repair according to claim 5, characterized in that: The pressure-equalizing pipeline (300) comprises a pressure-equalizing main pipe (12) and a pressure-equalizing isolation valve. One end of the pressure-equalizing main pipe (12) is connected to an upstream water diversion pipe (5), and the other end of the pressure-equalizing main pipe (12) is connected to a sand discharge pipe (16). The pressure-equalizing isolation valve comprises a first pressure-equalizing isolation valve (15), a pressure-equalizing switch control valve (13), and a second pressure-equalizing isolation valve (14) which are sequentially arranged on the pressure-equalizing main pipe (12). A sand discharge pipe (16) communicating with an inner cavity of the valve body (1) is arranged at the lower part of the valve body (1), and a sand discharge valve (11) is arranged on the sand discharge pipe (16). The first pressure-equalizing isolation valve (15) is located at one end close to the upstream water diversion pipe (5), and the second pressure-equalizing isolation valve (14) is located between the valve body (1) and the sand discharge valve (11).

7. A method for sealing and withdrawing a water turbine inlet ball valve during maintenance according to claim 6, characterized in that: In step b, the method for introducing the upstream water pressure into the valve body (1) by using the equalizing pressure pipeline (300) is as follows: first, the first equalizing pressure isolation valve (15) and the second equalizing pressure isolation valve (14) are controlled to open, so that the upstream water diversion pipe (5) and the valve body (1) are connected to the equalizing pressure main pipe (12) respectively; then, the equalizing pressure switch control valve (13) is controlled to open, so that the upstream water diversion pipe (5) and the valve body (1) are connected, so that the water pressure of the upstream water diversion pipe (5) and the water inlet ball valve body (1) are equal.

8. A method for sealing and withdrawing a water turbine inlet ball valve during maintenance according to claim 5, characterized in that: In step a, the method for controlling the working seal (200) to switch to the input position is as follows: the working input chamber (104) of the working seal (200) introduces upstream water pressure to build up pressure, and the working exit chamber (103) is connected to drain water to lose pressure, so that the working seal (200) switches from the exit position to the input position.

9. A method for sealing and flat-pressing withdrawal of a water turbine inlet ball valve for inspection and repair according to claim 5, characterized in that: In step c, the method for controlling the pressure of the maintenance exit chamber (102) in the maintenance seal (100) to be greater than the pressure of the maintenance input chamber (101) is as follows: the maintenance exit chamber (102) is pressurized by introducing upstream water pressure, and the maintenance input chamber (101) is connected to drain water to lose pressure, so that the maintenance movable ring (3) of the maintenance seal (100) is switched from the input position to the exit position.

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