High-pressure regulating valve for steam turbine

Abstract

A high-pressure regulating valve for a steam turbine, relating to the technical field of valves. The regulating valve comprises a valve housing, a valve rod, a valve cover, a valve seat, a pre-opening valve, and a main butterfly valve; a steam channel and a mounting port in communication with the steam channel are formed in the valve housing; the valve cover is mounted at the mounting port; the valve seat is mounted at a steam outlet of the steam channel; the valve seat is provided with a delivery channel in communication with the steam outlet; a sealing cover is provided in the valve housing; and when the valve rod drives the pre-opening valve to move away from a steam passing hole of the main butterfly valve, steam can flow to the other side of the main butterfly valve along the steam passing hole and a balance hole on a screw plug, thereby reducing the pressure difference between the front and the rear of the main butterfly valve, and thus enabling the main butterfly valve to be opened more conveniently. The described structure can keep the integrity of the valve rod structure; the valve rod is not easily broken when in use; and the formation of the balance hole in the main butterfly valve is avoided, ensuring the sealing performance when the valve is closed.

Description

A high-pressure regulating valve for steam turbines Technical Field

[0001] This invention relates to the field of valve technology, and specifically to a high-pressure regulating valve for steam turbines. Background Technology

[0002] The turbine control valve is an extremely important component of the turbine. It controls the turbine's operation, regulates the steam intake, and thus controls the turbine's start-up, shutdown, operating speed, and power output after grid connection. Based on the unit size and the valve stem lifting force, existing control valves are basically divided into two categories: one with a pre-opening valve for unloading and the other without a pre-opening valve for unloading. Control valves with a pre-opening valve for unloading can greatly reduce the steam force acting on the valve disc, reducing the lifting force required to open the valve disc.

[0003] When the space between the main valve disc protective sleeve, valve stem, and main valve disc forms an unloading chamber, the valve stem head and the small hole on the main valve disc form a pre-opening valve. A groove is provided on the conical surface of the guide part of the valve stem head that contacts the main valve disc. A steam flow channel is provided in the groove to allow steam to flow. The groove will damage the integrity of the valve stem structure, making the valve stem risky to break. In addition, the steam flow channel in the groove will also reduce the sealing performance of the main valve disc.

[0004] In summary, existing control valves suffer from problems such as easy breakage of the valve stem and poor sealing performance of the main valve disc. Summary of the Invention

[0005] The purpose of this invention is to solve the problems of easy breakage of valve stems and poor sealing performance of main valve discs in existing regulating valves. Therefore, this invention provides a high-pressure regulating valve for steam turbines.

[0006] The technical solution of the present invention is: a high-pressure regulating valve for a steam turbine, comprising a valve body, a valve stem, a valve cover, a valve seat, a pre-opening valve, and a main disc valve. The valve body has a steam passage and an installation port communicating with the steam passage. The valve cover is installed at the installation port, and the valve seat is installed at the steam outlet of the steam passage. The valve seat has a conveying passage communicating with the steam outlet. A sealing cover is provided inside the valve body, and a valve disc sleeve extending into the steam passage is connected to the sealing cover. The main disc valve is slidably installed on the valve disc sleeve. The valve opening is adjusted by moving the main disc valve closer to or further away from the conveying passage.

[0007] One end of the valve stem passes through the valve cover and extends into the valve disc sleeve. The pre-opening valve is installed on the end face of the valve stem and seals the steam vent of the main disc valve. The other end of the valve stem is located outside the valve housing and is adapted to be connected to a power unit.

[0008] A screw plug is connected to the inner side of the main disc valve. A first chamber is formed between the valve stem and the screw plug. A second chamber is formed between the pre-opening valve, the main disc valve, and the screw plug. The screw plug has a balance hole that connects the first chamber and the second chamber. When the pre-opening valve moves from the sealed position to the open position, the pre-opening valve abuts against the screw plug to push the screw plug and the main disc valve away from the conveying channel.

[0009] Furthermore, the main disc valve has an outwardly protruding sealing ring on the side near the delivery channel, the area of ​​the sealing ring on the side away from the main disc valve gradually decreases, and the cross-section of the sealing ring is two symmetrically distributed cones.

[0010] Furthermore, an inner sleeve is connected to the sealing cap and fitted onto the outside of the valve stem, one end of which is inserted into the screw plug, and an outer sleeve is connected to the valve cover and fitted onto the outside of the valve stem.

[0011] Furthermore, the inner sleeve is a square tube, and the screw plug has a square hole for engaging with the inner sleeve.

[0012] Furthermore, the inner sleeve and the outer sleeve are each provided with a plurality of sealing grooves evenly distributed along the axial direction.

[0013] Furthermore, the inner side of the screw plug is connected to a limiting platform for abutting against one end of the inner sleeve inserted into the screw plug, and the maximum opening position of the main disc valve is controlled by the limiting platform and the inner sleeve.

[0014] Furthermore, the valve seat is mounted on the valve housing by an interference fit, and the diameter of the inner wall of the delivery channel gradually increases in the direction away from the main disc valve.

[0015] Furthermore, the valve disc sleeve has an annular groove for accommodating the main disc valve.

[0016] Furthermore, a guide rib is connected to the inner wall of the steam passage on the side away from the steam inlet to prevent eddy current loss in the steam flow within the valve body.

[0017] Furthermore, the valve housing is provided with a high-pressure steam leakage hole communicating with the valve stem and the inner sleeve, and the valve cover is provided with a medium-pressure steam leakage hole and a low-pressure steam leakage hole communicating with the valve stem and the outer sleeve.

[0018] Compared with the prior art, the present invention has the following advantages:

[0019] 1. The high-pressure regulating valve for steam turbines provided by the present invention first drives the pre-opening valve away from the steam inlet of the main disc valve through the valve stem. At this time, steam can flow along the steam inlet and the balance hole on the screw plug to the other side of the main disc valve, thereby reducing the pressure difference before and after the main disc valve, making it easier to open the main disc valve. While realizing the pre-opening valve, the integrity of the valve stem structure is maintained, the valve stem is not easy to break during use, and the balance hole in the main disc valve is avoided, ensuring the sealing performance when the valve is closed.

[0020] 2. The high-pressure regulating valve for steam turbines provided by the present invention has a linear contact between the main disc valve and the delivery channel, resulting in a smaller contact area and faster opening and closing speed. Furthermore, this type of main disc valve structure can reduce the fluctuation of steam pressure after the valve, improve the stability of the valve, and at the same time prevent the steam channel between the main disc valve and the valve seat from forming a Laval nozzle shape. Attached Figure Description

[0021] Figure 1 is a schematic diagram of the overall structure of the high-pressure regulating valve for steam turbines of the present invention;

[0022] Figure 2 is a schematic diagram of the main disc valve in the maximum open position in Figure 1;

[0023] Figure 3 is a cross-sectional view at point AA in Figure 1;

[0024] Figure 4 is an enlarged view of region A in Figure 1.

[0025] In the diagram: 1. Valve housing; 2. Valve stem; 3. Valve cover; 4. Valve seat; 5. Pre-opening valve; 6. Main disc valve; 7. Steam passage; 8. Mounting port; 9. Steam outlet; 10. Conveying passage; 11. Valve disc sleeve; 12. Steam vent; 13. Screw plug; 14. First chamber; 15. Second chamber; 16. Balance hole; 17. Sealing ring; 18. Inner sleeve; 19. Sealing cover; 20. Outer sleeve; 21. Square hole; 22. Sealing groove; 23. Limiting platform; 24. Annular groove; 25. Guide rib; 26. High-pressure steam leakage hole; 27. Medium-pressure steam leakage hole; 28. Low-pressure steam leakage hole; 29. ​​Steam inlet. Detailed Implementation

[0026] Specific Implementation Method 1: This implementation method is illustrated in Figures 1 to 4. It includes a valve housing 1, a valve stem 2, a valve cover 3, a valve seat 4, a pre-opening valve 5, and a main disc valve 6. A steam passage 7 is provided inside the valve housing 1, with an inlet 29 and an outlet 9, which are perpendicular to each other. An installation port 8 communicating with the steam passage 7 is also provided on the valve housing 1. The valve cover 3 is installed at the installation port 8, and the valve seat 4 is installed at the outlet 9 of the steam passage 7. The valve seat 4 has a conveying passage 10 communicating with the outlet 9. A sealing cover 19 is provided inside the valve housing 1, and a valve disc sleeve 11 extending into the steam passage 7 is connected to the sealing cover 19. The main disc valve 6 is slidably mounted on the valve disc sleeve 11. The valve opening is adjusted by the main disc valve 6 moving closer to or further away from the conveying passage 10. Adjustment is performed by having one end of the valve stem 2 pass through the valve cover 3 and extend into the valve disc sleeve 11. The pre-opening valve 5 is installed on the end face of the valve stem 2 and seals the steam hole 12 of the main disc valve 6. The steam hole 12 on the main disc valve 6 is connected to the conveying channel 10 of the valve seat 4. The other end of the valve stem 2 is located outside the valve body 1 and is suitable for connection to a power unit, which can be a hydraulic motor. A screw plug 13 is connected to the inner side of the main disc valve 6. A first chamber 14 is formed between the valve stem 2 and the screw plug 13. A second chamber 15 is formed between the pre-opening valve 5, the main disc valve 6, and the screw plug 13. The screw plug 13 has a balance hole 16 that connects the first chamber 14 and the second chamber 15. When the pre-opening valve 5 moves from the sealed position to the open position, the pre-opening valve 5 abuts against the screw plug 13 to push the screw plug 13 and the main disc valve 6 away from the conveying channel 10.

[0027] In this embodiment of the high-pressure regulating valve for steam turbines, the valve stem 2 first drives the pre-opening valve 5 away from the steam inlet 12 of the main disc valve 6. At this time, steam can flow along the steam inlet 12 and the balance hole 16 on the screw plug 13 to the other side of the main disc valve 6, thereby reducing the pressure difference before and after the main disc valve 6, making it easier to open the main disc valve 6. While realizing the pre-opening valve 5, the integrity of the valve stem 2 structure is maintained. The valve stem 2 is not easy to break during use, and the balance hole 16 is avoided in the main disc valve 6, ensuring the sealing performance when the valve is closed.

[0028] Specific Implementation Method Two: This implementation method is illustrated in Figure 4. The difference between this method and Specific Implementation Method One is that the main disc valve 6 has an outwardly protruding sealing ring 17 on the side near the delivery channel 10. The area of ​​the sealing ring 17 gradually decreases on the side away from the main disc valve 6. The cross-section of the sealing ring 17 consists of two symmetrically distributed cones. The sealing ring 17 of the main disc valve 6 and the delivery channel 10 are in linear contact, resulting in a smaller contact area and faster opening and closing speeds. Furthermore, this structure of the main disc valve 6 reduces steam pressure fluctuations downstream of the valve, improving valve stability, and simultaneously preventing the steam channel 7 between the main disc valve 6 and the valve seat 4 from forming a Laval nozzle shape. Other components and connections are the same as in Specific Implementation Method One.

[0029] Specific Implementation Method 3: This implementation method is illustrated in conjunction with Figure 1. The difference between this implementation method and Specific Implementation Method 2 is that an inner sleeve 18 is connected to the sealing cover 19 and sleeved on the outside of the valve stem 2. One end of the inner sleeve 18 is inserted into the screw plug 13. An outer sleeve 20 is connected to the valve cover 3 and sleeved on the outside of the valve stem 2. The inner sleeve 18 and the outer sleeve 20 can support the valve stem 2, making the movement of the valve stem 2 more stable and less prone to shaking. Other components and connections are the same as in Specific Implementation Method 2.

[0030] Specific Implementation Method Four: This implementation method is illustrated in Figure 3. The difference between this method and Specific Implementation Method Three is that the inner sleeve 18 is a square cylinder, and the screw plug 13 has a square hole 21 for mating with the inner sleeve 18. The square hole 21 serves as a limiting device. In this implementation method, the screw plug 13 is threadedly connected to the main disc valve 6, and installation is achieved by rotating the screw plug 13. The square limiting structure prevents relative rotation between the screw plug 13 and the main disc valve 6, ensuring a stable connection between them. Other components and connections are the same as in Specific Implementation Method Three.

[0031] Specific Embodiment Five: This embodiment is illustrated in conjunction with Figure 4. The difference between this embodiment and Specific Embodiment Three is that the inner sleeve 18 and the outer sleeve 20 are each provided with a plurality of sealing grooves 22 evenly distributed along the axial direction. The sealing grooves 22 are annular and located on the inner surfaces of the inner sleeve 18 and the outer sleeve 20. The sealing grooves 22 improve the sealing performance between the valve stem 2 and the inner sleeve 18 and the outer sleeve 20. Other components and connections are the same as in Specific Embodiment Three.

[0032] Specific Implementation Method Six: This implementation method is illustrated in Figure 4. The difference between this method and Specific Implementation Method Three is that a limiting platform 23 is connected to the inner side of the screw plug 13 to abut against the end of the inner sleeve 18 inserted into the screw plug 13. When the pre-opening valve 5 abuts against the screw plug 13, it will cause the screw plug 13 and the main disc valve 6 to move together. The limiting platform 23 will move along with the screw plug 13. When the limiting platform 23 abuts against the inner sleeve 18, the screw plug 13 can no longer move, and the main disc valve 6 can no longer move, thus limiting the maximum opening position of the main disc valve 6. Other components and connections are the same as in Specific Implementation Method Three.

[0033] Specific Implementation Method Seven: This implementation method is illustrated in Figure 1. The difference between this method and Specific Implementation Method One is that the valve seat 4 is mounted on the valve body 1 via an interference fit. The diameter of the inner wall of the delivery channel 10 gradually increases in the direction away from the main disc valve 6. When steam flows inside the delivery channel 10, the gradually increasing diameter of the inner wall of the delivery channel 10 exerts lateral pressure on the inner wall, making the connection between the valve seat 4 and the valve body 1 more stable. Other components and connections are the same as in Specific Implementation Method One.

[0034] Specific Implementation Method Eight: This implementation method is illustrated in conjunction with Figure 4. The difference between this implementation method and Specific Implementation Method One is that the valve disc sleeve 11 has an annular groove 24 for accommodating the main disc valve 6. When the main disc valve 6 moves to its maximum open position, it can completely conceal the interior of the inner valve disc sleeve 11, reducing the impact of steam flow within the steam passage 7 and resulting in more stable operation. Other components and connections are the same as in Specific Implementation Method One.

[0035] Specific Implementation Method Nine: This implementation method is described with reference to Figures 1 and 2. The difference between this implementation method and Specific Implementation Method One is that a guide rib 25 is connected to the inner wall of the steam passage 7 on the side away from the steam inlet 29. The guide rib 25 guides the steam flow and prevents eddy current losses in the valve body 1. Other components and connections are the same as any one of Specific Implementation Methods One to Six.

[0036] Specific Embodiment Ten: This embodiment is illustrated in conjunction with Figure 1. The difference between this embodiment and Specific Embodiment One is that the valve body 1 has a high-pressure steam leakage hole 26 communicating with the valve stem 2 and the inner sleeve 18, while the valve cover 3 has a medium-pressure steam leakage hole 27 and a low-pressure steam leakage hole 28 communicating with the valve stem 2 and the outer sleeve 20. The high-pressure steam leakage hole 26 collects steam leakage generated between the valve stem 2 and the inner sleeve 18, while the medium-pressure and low-pressure steam leakage holes 27 and 28 collect steam leakage generated between the valve stem 2 and the outer sleeve 20. Other components and connections are the same as in any one of Specific Embodiments One to Six.

[0037] How to use this implementation method:

[0038] In the initial state, both the pre-opening valve 5 and the main disc valve 6 are in the sealed position. When the hydraulic motor is started, the hydraulic motor drives the valve stem 2 to move towards the outside of the valve body 1. The valve stem 2 then drives the pre-opening valve 5 to move. At this time, the pre-opening valve 5 is separated from the steam hole 12 of the main disc valve 6. Steam can then flow along the steam hole 12 and the balance hole 16 on the screw plug 13 to the other side of the main disc valve 6, thereby reducing the pressure difference before and after the main disc valve 6 and making it easier to open the main disc valve 6.

[0039] As the pre-opening valve 5 continues to move, it will come into contact with the screw plug 13, thereby pushing the screw plug 13 and the main disc valve 6 to move together, causing the sealing ring 17 of the main disc valve 6 to separate from the conveying channel 10 of the valve seat 4. At this time, the valve is already in the open state until the limiting platform 23 on the screw plug 13 comes into contact with the inner sleeve 18. At this time, the main disc valve 6 moves to the maximum opening position, and the valve opening is at its maximum.

[0040] The content of this invention is not limited to the above-described embodiments; a combination of one or more specific embodiments can also achieve the purpose of the invention.

Claims

1. A high-pressure regulating valve for a steam turbine, comprising: The valve housing (1), valve stem (2), valve cover (3), valve seat (4), pre-opening valve (5), and main disc valve (6) are provided. The valve housing (1) has a steam passage (7) and an installation port (8) communicating with the steam passage (7). The valve cover (3) is installed at the installation port (8). The valve seat (4) is installed at the steam outlet (9) of the steam passage (7). The valve seat (4) has a conveying passage (10) communicating with the steam outlet (9). The valve housing (1) has a sealing cover (19) inside. A valve disc sleeve (11) extending into the steam passage (7) is connected to the sealing cover (19). The main disc valve (6) is slidably installed on the valve disc sleeve (11). The valve opening is adjusted by moving the main disc valve (6) closer to or further away from the conveying passage (10). One end of the valve stem (2) passes through the valve cover (3) and extends into the valve disc sleeve (11). The pre-opening valve (5) is installed on the end face of the valve stem (2) and seals the steam hole (12) of the main disc valve (6). The other end of the valve stem (2) is located outside the valve body (1) and is suitable for connection with the power unit. The main disc valve (6) is characterized by having a screw plug (13) connected to its inner side, forming a first chamber (14) between the valve stem (2) and the screw plug (13), forming a second chamber (15) between the pre-opening valve (5), the main disc valve (6) and the screw plug (13), and the screw plug (13) having a balance hole (16) communicating between the first chamber (14) and the second chamber (15). When the pre-opening valve (5) moves from the sealed position to the open position, the pre-opening valve (5) abuts against the screw plug (13) to push the screw plug (13) and the main disc valve (6) away from the conveying channel (10).

2. The high-pressure regulating valve for a steam turbine according to claim 1, characterized in that, The main disc valve (6) has an outwardly protruding sealing ring (17) on the side near the conveying channel (10). The area of ​​the sealing ring (17) on the side away from the main disc valve (6) gradually decreases. The cross-section of the sealing ring (17) is two symmetrically distributed cones.

3. A high-pressure regulating valve for a steam turbine according to claim 1, characterized in that, The sealing cap (19) is connected to an inner sleeve (18) that is sleeved on the outside of the valve stem (2). One end of the inner sleeve (18) is inserted into the screw plug (13). The valve cover (3) is connected to an outer sleeve (20) that is sleeved on the outside of the valve stem (2).

4. A high-pressure regulating valve for a steam turbine according to claim 3, characterized in that, The inner sleeve (18) is a square tube, and the screw plug (13) has a square hole (21) for cooperating with the inner sleeve (18).

5. A high-pressure regulating valve for a steam turbine according to claim 3, characterized in that, The inner sleeve (18) and the outer sleeve (20) are respectively provided with a plurality of sealing grooves (22) evenly distributed along the axial direction.

6. A high-pressure regulating valve for a steam turbine according to claim 3, characterized in that, The inner side of the plug (13) is connected to a limiting platform (23) for abutting against one end of the inner sleeve (18) inserted into the plug (13). The maximum opening position of the main disc valve (6) is controlled by the limiting platform (23) and the inner sleeve (18).

7. A high-pressure regulating valve for a steam turbine according to claim 1, characterized in that, The valve seat (4) is mounted on the valve housing (1) by an interference fit, and the diameter of the inner wall of the conveying channel (10) gradually increases in the direction away from the main disc valve (6).

8. A high-pressure regulating valve for a steam turbine according to claim 1, characterized in that, The valve disc sleeve (11) has an annular groove (24) for accommodating the main disc valve (6).

9. A high-pressure regulating valve for a steam turbine according to any one of claims 1-6, characterized in that, A guide rib (25) is connected to the inner wall of the steam passage (7) on the side away from the steam inlet (29) to prevent the steam flow from generating eddy current losses in the valve body (1).

10. A high-pressure regulating valve for a steam turbine according to any one of claims 1-6, characterized in that, The valve housing (1) is provided with a high-pressure steam leakage hole (26) that communicates between the valve stem (2) and the inner sleeve (18), and the valve cover (3) is provided with a medium-pressure steam leakage hole (27) and a low-pressure steam leakage hole (28) that communicate between the valve stem (2) and the outer sleeve (20).

Images