Double-seal ball valve for water turbine inlet

Abstract

The utility model discloses a double-seal ball valve for water inlet of water turbine, belongs to the control device of water conservancy equipment accessory, and sets up the sealing ring on both sides of the water inlet and the water outlet of valve ball, and the mutual cooperation of two sealing rings can adapt to various working conditions of ball valve, provide better sealing effect, and PTFE contact surface can avoid the influence of water on the hydraulic system to the operation of ball valve, and the diversion groove can avoid the abrasion of silt sinking to ball valve, and the service life is long, and the effect is remarkable.

Description

Technical Field

[0001] This utility model belongs to the field of water conservancy equipment control technology, and in particular relates to ball valves, specifically a double-sealed ball valve for water turbine inlet. Background Technology

[0002] The turbine inlet ball valve is one of the core safety devices in a hydropower station. It is installed on the pressure pipe before the inlet of the turbine casing of a turbine unit with a maximum static head of 200 meters or more. It undertakes key functions such as cutting off water flow and ensuring the safety of unit maintenance. Failure of the turbine inlet ball valve may lead to serious safety accidents.

[0003] Currently disclosed patented technologies for turbine inlet ball valves still suffer from various problems. For example, insufficient sealing reliability: traditional T-shaped seals are prone to particle embedding in silty water conditions, leading to scratches on the sealing surface. CN206092960U uses multiple sealing rings, such as a combination of a first O-ring, a first sealing ring, and a sand-blocking sealing ring. However, this combination tends to prevent silt and water from entering the oil chamber, but it doesn't improve the sealing surface of the sealing ring. Silt can still accumulate on the sealing surface of the sealing ring, causing scratches and wear as the ball valve operates. Furthermore, after seal wear has occurred, the sealing surfaces of turbine sealing structures are mostly hard metal seals. Hard metal seals rely on initial preload. After the sealing surface of a hard metal seal wears down, the specific pressure drops, causing leakage to multiply, and the rate of increase in leakage accelerates. If the wear is not detected early, emergency shutdown and replacement are necessary, making it impossible to wait for routine maintenance. This not only increases production and maintenance costs but also poses a significant challenge to the safety and stability of the turbine's normal operation.

[0004] Therefore, people are still constantly exploring technologies and design ideas from various directions to improve the performance of the turbine inlet ball valve as much as possible, so as to meet the requirements. Utility Model Content

[0005] To address the shortcomings of existing technologies, this invention proposes a double-sealed ball valve for turbine inlet, which effectively reduces the impact of silt on the seal.

[0006] The technical problem to be solved by this utility model is achieved through the following technical solution:

[0007] A double-sealed ball valve for turbine inlet includes a valve body and a valve ball. The valve body has an inlet and an outlet at its two ends, respectively. A water passage is provided in the center of the valve ball. A working sealing pair is provided in the outlet of the valve body, and a maintenance sealing pair is provided in the inlet of the valve body. In this invention, the working sealing pair includes a working sealing ring that mates with the valve ball. The working sealing ring is hydraulically driven, and the contact surface between the working sealing ring and the valve ball is the working sealing surface. The maintenance sealing pair includes a maintenance sealing ring that mates with the valve ball. The maintenance sealing pair is hydraulically driven, and the contact surface between the maintenance sealing pair and the valve ball is the maintenance sealing surface.

[0008] In this invention, the inner diameter of the outlet is larger than the inner diameter of the inlet, and the inner wall of the working sealing ring is stepped, with the inner diameter of the side facing the outlet being larger than the inner diameter of the side near the valve ball. When the ball valve is closed, the water outside the outlet provides additional pressure toward the valve ball through the stepped surface of the working sealing ring.

[0009] The working sealing ring and the inner wall of the valve body form an annular working sealing hydraulic chamber. The two sides of the working sealing ring slide and seal against the inner wall of the valve body. A working sealing boss is located in the middle of the working sealing ring, within the working sealing chamber, dividing it into a large working chamber and a small working chamber. The large working chamber is closer to the outlet, while the small working chamber is farther from the outlet relative to the large working chamber. The working sealing boss slides and seals against the inner wall of the valve body. The large and small working chambers are respectively connected to a three-way solenoid valve via hydraulic channels. The maintenance sealing ring and the inner wall of the valve body are separated... A ring-shaped maintenance sealing hydraulic chamber is separated. The two sides of the maintenance sealing ring slide and seal with the inner wall of the valve body. A maintenance sealing boss is provided in the middle of the maintenance sealing ring. The maintenance sealing boss is located in the maintenance sealing chamber and divides it into an outer maintenance chamber and an inner maintenance chamber. The outer maintenance chamber is close to the water inlet, and the inner maintenance chamber is far away from the water inlet relative to the outer maintenance chamber. The maintenance sealing boss slides and seals with the inner wall of the valve body. The outer maintenance chamber and the inner maintenance chamber are respectively connected to a three-way solenoid valve through a hydraulic channel. The three-way solenoid valve of the working sealing pair and the three-way solenoid valve of the maintenance sealing pair are controlled independently.

[0010] The axial width of the large working chamber relative to the water flow direction is greater than that of the small working chamber.

[0011] A disc spring is installed inside the maintenance cavity, and the center of the disc spring coincides with the center of the valve body inlet.

[0012] The sealing fit structure between the inner wall of the valve body and the working sealing ring and the maintenance sealing ring includes a sealing ring disposed on the contact surface between the working sealing ring and the maintenance sealing ring and the inner wall of the valve body. The sealing ring is embedded in the working sealing ring and the maintenance sealing ring, and an elastic ring is provided as a gasket on the inner side of the sealing ring.

[0013] The contact surface on the inner wall of the valve body that seals with the working sealing ring and the maintenance sealing ring is set as a fine mesh surface. Its surface is flat and fits snugly against the working sealing ring or the maintenance sealing ring. Shallow grooves are set within the fine mesh, and the shallow grooves are filled with oleophilic and hydrophobic filler and leveled. The oleophilic and hydrophobic material is PTFE (polytetrafluoroethylene).

[0014] In this utility model, the inner wall of the water passage of the valve ball is uniformly provided with guide grooves. The guide grooves are arc-shaped grooves, arranged in parallel, and their arrangement direction is spirally arranged in the center along the water flow direction in the water passage. The angle between the spiral direction and the water flow direction is 15°.

[0015] Compared with the prior art, the present invention has the following advantages:

[0016] (1) This application achieves double sealing of the ball valve by setting sealing rings on both sides of the ball. The two seals cooperate with each other to provide a better sealing effect for the working state of the ball valve.

[0017] (2) The present application provides a stepped surface on the working sealing ring at the working sealing pair, so that when the ball valve is closed, the water pressure outside the outlet provides an additional thrust toward the valve ball, thereby further improving the sealing effect;

[0018] (3) In this application, the cross-section of the large working cavity at the working sealing pair is larger than the cross-section of the small working cavity, so that when the working sealing ring is subjected to water pressure and water flow impact, the loosening of the working sealing ring on the valve ball will be additionally buffered, avoiding excessive instantaneous pressure from causing excessive impact on the hydraulic system and damaging the hydraulic system.

[0019] (4) In this application, a disc spring is installed in the maintenance outer cavity of the maintenance sealing pair to provide a certain initial pressure for the maintenance sealing ring to seal the valve ball. At the same time, the hydraulic oil in the maintenance outer cavity also effectively protects the disc spring and extends its service life.

[0020] (5) The sliding sealing structure between the working sealing ring and the maintenance sealing ring and the inner wall of the valve body in this application, on the one hand, the elastic sealing ring on the sealing ring side keeps the sealing surface tightly fitted, and on the other hand, the PTFE oil-repellent structure on the inner wall of the valve body keeps the oil and water separation effect, which can effectively prevent water from entering the sealing cavity and causing oil and water mixing, thereby damaging the hydraulic system.

[0021] (6) After the sealing surfaces of the working sealing pair and the maintenance sealing pair of this application are worn, they can continue to squeeze the valve ball under the push of the hydraulic system to maintain the sealing effect of the ball valve and bring continuous safety and stability to the turbine.

[0022] (7) This application provides a spiral guide groove inside the valve ball to guide the flowing water into a spiral flow mixed flow, which drives the mud and sand in the water to flow together, so as to prevent them from sinking under their own weight during the flow and falling into the gap of the valve body on the lower side of the ball valve, thereby causing wear when the ball valve is operated. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall structure of this application;

[0024] Figure 2 This is a schematic diagram of the sliding sealing surface structure of the valve body inner wall in this application;

[0025] Figure 3 for Figure 1 A schematic diagram of the cross-sectional structure at point C of the middle valve ball;

[0026] Figure 4 This is a schematic diagram showing the unfolded inner wall of the water passage in the center of the valve ball.

[0027] In the diagram: Valve body 1, Valve ball 2, Water passage 21, Guide groove 22, Working sealing ring 3, Working sealing surface 31, Working hydraulic system 32, Working hydraulic three-way solenoid valve 33, Working sealing ring 34, Working sealing boss 35, Inspection sealing ring 4, Inspection sealing surface 41, Inspection hydraulic system 42, Inspection hydraulic three-way solenoid valve 43, Inspection sealing ring 44, Inspection sealing boss 45, Disc spring 5, Valve shaft 6, Valve ball mounting bearing 61, Fine mesh surface 7, Oleophilic and hydrophobic packing 71. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific preferred embodiments, but this does not limit the scope of protection of the present invention.

[0029] A double-seal ball valve for turbine inlet includes a valve body 1 and a valve ball 2. The two ends of the valve body 1 are an inlet and an outlet, respectively. The center of the valve ball 2 is configured as a water passage 21. A working sealing pair is provided in the outlet of the valve body 1. The working sealing pair serves as the main seal and is used to cooperate with the valve ball 2 to achieve sealing control for water passage and water cut-off. A maintenance sealing pair is provided in the inlet of the valve body 1. The maintenance sealing pair serves as a maintenance seal and is used to cooperate with the working sealing pair to achieve sealing control upstream of the valve ball 2.

[0030] exist Figure 1In the process, the working sealing pair includes a working sealing ring 3 that mates with the valve ball 2. The working sealing ring 3 is driven by the working hydraulic system 32. The contact surface between the working sealing ring 3 and the valve ball 2 is the working sealing surface 31. The inner wall of the working sealing ring 3 is stepped, and its inner diameter on the side facing the water outlet is larger than the inner diameter on the side closer to the valve ball 2. An annular working sealing hydraulic chamber is separated between the working sealing ring 3 and the inner wall of the valve body 1. The working sealing hydraulic chamber is filled with hydraulic oil. A working sealing boss 35 is provided in the middle of the working sealing ring 3. The working sealing boss 35 is located in the working sealing chamber and divides it into a large working chamber A1 and a small working chamber A2. The working sealing boss 35 is in sliding sealing cooperation with the inner wall of the valve body 1. The working sealing rings 3 on the left and right sides of the working sealing boss 35 are in sliding cooperation with the inner wall of the valve body 1. The sliding direction is parallel to the water flow direction. The large working chamber A1 and the small working chamber A2 are respectively connected to the working hydraulic three-way solenoid valve 33 by the working hydraulic system 32 for reversing adjustment. The axial width of the large working chamber A1 relative to the water flow direction is greater than that of the small working chamber A2.

[0031] The maintenance sealing pair includes a maintenance sealing ring 4 that mates with the valve ball 2. The maintenance sealing ring 4 is driven by the maintenance hydraulic system 42. The contact surface between the maintenance sealing ring 4 and the valve ball 2 is the maintenance sealing surface 41. An annular maintenance sealing hydraulic cavity is separated between the maintenance sealing ring 4 and the inner wall of the valve body 1. The maintenance sealing hydraulic cavity is filled with hydraulic oil. A maintenance sealing boss 45 is provided in the middle of the maintenance sealing ring 4. The maintenance sealing boss 45 is located in the maintenance sealing cavity and divides it into an outer maintenance cavity B. 2. The maintenance inner cavity B1 is equipped with a maintenance sealing boss 45 that slides and seals with the inner wall of the valve body 1. The maintenance sealing rings 4 on the left and right sides of the maintenance sealing boss 45 slide and seal with the inner wall of the valve body 1. The sliding direction is parallel to the water flow direction. The maintenance outer cavity B2 and the maintenance inner cavity B1 are respectively connected to the maintenance hydraulic three-way solenoid valve 43 by the maintenance hydraulic system 42 for reversing adjustment. A disc spring 5 is installed in the maintenance outer cavity B2, and the center of the disc spring 5 coincides with the center of the water inlet of the valve body 1.

[0032] The working sealing ring 3 and the maintenance sealing ring 4 have the same sliding sealing structure as the inner wall of the valve body 1, such as... Figure 2 As shown, sealing rings 34 / 44 are provided on the working sealing ring 3 and the maintenance sealing ring 4. The sealing rings 34 / 44 are embedded in the wall of the sealing surface of the working sealing ring 3 and the maintenance sealing ring 4. An elastic ring is provided on the inner side of the sealing rings 34 / 44 to provide elasticity and support the sealing rings 34 / 44 to closely contact the inner wall of the valve body 1. Correspondingly, the corresponding position of the inner wall of the valve body 1 is set as a fine mesh surface 7. The surface of the fine mesh surface 7 is flat, and shallow grooves are set in the fine mesh. The shallow grooves are filled with PTFE oleophilic and hydrophobic filler 71 and leveled. Its flat surface avoids water retention. The oleophilic and hydrophobic properties of PTFE make the edge of the fine mesh surface 7 area present a large tension, preventing water intrusion and effectively isolating the water and hydraulic oil on both sides.

[0033] exist Figure 3 and Figure 4 The valve ball 2 has a water passage 21 with uniformly arranged guide grooves 22 on its inner wall. The guide grooves 22 are parallel arc-shaped grooves arranged in a spiral shape around the water flow direction. The spiral direction and the water flow direction are at an angle of 15°. The small-angle spiral grooves can guide the water flow into a spiral flow mixed flow, carrying the mud and sand in the water flow together, and preventing the mud and sand from settling under their own weight during the flow and falling into the gaps in the inner wall of the ball valve to cause wear. The 15° angle ensures that when the water flow speed is 3-5 m / s, particles no larger than 100 μm in the water flow are entrained in the mixed flow to prevent them from settling.

[0034] The working strategy of this application for double sealing is as follows: When the sealing ball valve is open, the maintenance sealing hydraulic system is driven, oil enters the maintenance inner cavity B1, pushing the maintenance sealing ring 4 away from the valve ball 2. Water enters the middle of the ball valve, the working sealing hydraulic system is driven, oil enters the working small cavity A2, pushing the working sealing ring 3 away from the valve ball 2. The valve ball 2 is released from the sealing state. Under the drive of external force, the valve shaft 6 rotates along the valve ball mounting bearing 61. After the valve ball 2 rotates 90°, the ball valve is fully open. When the sealing ball valve is closed, the valve ball 2 rotates to the fully closed position. The working sealing hydraulic system is driven, oil enters the working large cavity A1, pushing the working sealing ring 3 to press against the valve ball 2 for sealing. Then the maintenance sealing system is driven, oil enters the maintenance outer cavity B2, pushing the maintenance sealing ring 4 to press against the valve ball 2 for sealing. A small amount of water may remain at the valve ball 2. Then the working sealing ring 3 performs a short-stroke retraction and then continues to perform long-term sealing. If the sealing surface of the working sealing ring 3 is worn, it will be displaced under the drive of the working sealing hydraulic system, but it can still maintain the same sealing effect as the valve ball 2 at the same pressure, which can effectively compensate for the amount of wear.

[0035] In summary, based on the above structure and working process, it can be seen that the turbine inlet double-seal ball valve of this application can achieve a very good sealing effect, effectively avoiding adverse effects such as erosion and wear of the ball valve by silt, and the effect is significant.

Claims

1. A double-seal ball valve for turbine inlet, comprising a valve body and a valve ball, wherein the two ends of the valve body are an inlet and an outlet respectively, a water passage is provided in the center of the valve ball, a working sealing pair is provided in the outlet of the valve body, and a maintenance sealing pair is provided in the inlet of the valve body, characterized in that: The working sealing pair includes a working sealing ring that mates with the valve ball. The working sealing ring is hydraulically driven, and its contact surface with the valve ball is the working sealing surface. The maintenance sealing pair includes a maintenance sealing ring that mates with the valve ball. The maintenance sealing pair is hydraulically driven, and its contact surface with the valve ball is the maintenance sealing surface. The inner diameter of the outlet is larger than the inner diameter of the inlet. The inner wall of the working sealing ring is stepped, with the inner diameter on the side facing the outlet being larger than the inner diameter on the side closer to the valve ball. An annular working sealing hydraulic cavity is separated between the working sealing ring and the inner wall of the valve body. The two sides of the working sealing ring slide and seal with the inner wall of the valve body. A working sealing boss is provided in the middle of the working sealing ring. The working sealing boss is located in the working sealing cavity and divides it into a large working cavity and a small working cavity. The large working cavity is closer to the outlet. The small working chamber is farther from the outlet than the large working chamber. The working sealing boss slides and seals with the inner wall of the valve body. The large working chamber and the small working chamber are respectively connected to the three-way solenoid valve through hydraulic channels. The maintenance sealing ring is separated from the inner wall of the valve body to form an annular maintenance sealing hydraulic chamber. The two sides of the maintenance sealing ring slide and seal with the inner wall of the valve body. A maintenance sealing boss is provided in the middle of the maintenance sealing ring. The maintenance sealing boss is located in the maintenance sealing chamber and divides it into an outer maintenance chamber and an inner maintenance chamber. The outer maintenance chamber is close to the inlet, and the inner maintenance chamber is farther from the inlet than the outer maintenance chamber. The maintenance sealing boss slides and seals with the inner wall of the valve body. The outer maintenance chamber and the inner maintenance chamber are respectively connected to the three-way solenoid valve through hydraulic channels. The three-way solenoid valve of the working sealing pair and the three-way solenoid valve of the maintenance sealing pair are controlled independently.

2. The ball valve according to claim 1, characterized in that: The axial width of the large working chamber relative to the water flow direction is greater than that of the small working chamber.

3. The ball valve according to claim 1, characterized in that: A disc spring is installed inside the maintenance cavity, and the center of the disc spring coincides with the center of the valve body inlet.

4. The ball valve according to claim 1, characterized in that: The sealing fit structure between the inner wall of the valve body and the working sealing ring and the maintenance sealing ring includes a sealing ring disposed on the contact surface between the working sealing ring and the maintenance sealing ring and the inner wall of the valve body. The sealing ring is embedded in the working sealing ring and the maintenance sealing ring, and an elastic ring is provided as a gasket on the inner side of the sealing ring.

5. The ball valve according to claim 4, characterized in that: The contact surface on the inner wall of the valve body that seals with the working sealing ring and the maintenance sealing ring is set as a fine mesh surface. Its surface is flat and fits the working sealing ring or the maintenance sealing ring. Shallow grooves are set in the fine mesh, and the shallow grooves are filled with oleophilic and hydrophobic filler and leveled.

6. The ball valve according to claim 1, characterized in that: The inner wall of the water passage of the valve ball is uniformly provided with guide grooves. The guide grooves are arc-shaped grooves, arranged in parallel. Their arrangement direction is a central spiral along the water flow direction in the water passage, and the angle between the spiral direction and the water flow direction is 15°.

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