A turbine governing valve damping structure based on unloading chamber pressure active control and a working method thereof

Abstract

The application discloses a kind of based on unloading chamber pressure active control steam turbine governing valve damping structure and its working method, including valve stem, valve cover, valve shell, valve sleeve, valve disc and valve seat, valve disc separates into unloading chamber and lower chamber with valve inner space, second unloading hole is provided on valve cover and communicated with unloading chamber, second unloading hole is communicated with high-pressure steam source outlet by pipeline and forms unloading chamber high-pressure bypass, and loading valve is provided on the bypass pipeline;The damping structure further includes unloading mechanism for reducing the pressure difference between unloading chamber and lower chamber, the damping structure is pre-opening valve installed in the center of valve disc, or including second unloading hole is communicated with low-pressure steam source inlet by pipeline and forms unloading chamber low-pressure bypass, and unloading valve is provided on the bypass pipeline;By actively adjusting the pressure of unloading chamber, while reducing the lifting force required when opening the governing valve, the pressure in the unloading chamber can also be increased after the governing valve is opened, thereby suppressing the vibration of the governing valve.

Description

Technical Field

[0001] This invention relates to the field of fluid control equipment technology, and more specifically, to a steam inlet regulating valve for a power plant turbine, and particularly to a vibration reduction structure for a turbine regulating valve based on active control of unloading chamber pressure and its working method. Background Technology

[0002] As a key control component for steam turbine inlet, the regulating valve ensures the safe and efficient operation of the turbine. Under conditions of large pressure differential and small valve opening, the vibration problem of the regulating valve is particularly pronounced. Vibration can lead to numerous problems such as valve stem breakage and drain pipe rupture, seriously threatening the safe operation of the unit. Therefore, addressing the vibration of the regulating valve is essential.

[0003] The existing steam inlet regulating valve structure of power plant steam turbines is as follows: Figure 1 As shown, the control valve has a higher inlet pressure and a lower outlet pressure. To ensure the vertical movement of the valve stem relative to the valve body, the valve stem relative to the pre-opening valve disc, and the valve disc relative to the valve sleeve, there must be a certain gap between the components. Therefore, when the control valve is fully closed, the high-pressure steam at the inlet will enter the unloading chamber through the unloading hole and the fit gap between the valve disc and the valve sleeve, filling the unloading chamber with high-pressure steam. At this time, there is a huge pressure difference between the unloading chamber and the lower chamber of the valve disc. This pressure difference generates a large axial downward force, resulting in a huge lifting force required when the control valve opens. To reduce the lifting force during opening, existing control valves are designed with a pre-opening valve structure. When the control valve is opened from fully closed, the valve stem lifts first to open the pre-opening valve. The high-pressure steam in the unloading chamber flows to the lower chamber of the valve disc through the pre-opening valve, reducing the pressure in the unloading chamber, while the pressure in the lower chamber of the valve disc remains approximately unchanged. This reduces the pressure difference between the unloading chamber and the lower chamber of the valve disc, thus reducing the lifting force. When the control valve is running stably at a certain opening, in order to reduce valve stem vibration, a first unloading hole is set on the valve sleeve. The principle is that high-pressure steam in front of the valve continuously enters the unloading chamber through the first unloading hole, which increases the pressure between the unloading chamber and the lower chamber of the valve disc to suppress vibration.

[0004] In summary, the pre-opening valve in the control valve is primarily designed to reduce the pressure in the unloading chamber when the control valve is open, thereby reducing the lifting force. The first unloading orifice, on the other hand, is designed to increase the pressure in the unloading chamber after the valve position stabilizes, thus suppressing vibration. However, the opening and closing of the pre-opening valve is fixed, and the first unloading orifice can only be continuously open. When the pre-opening valve opens after the valve position stabilizes, it increases the difficulty of establishing a pressure difference between the unloading chamber and the lower chamber of the valve disc. Conversely, when the first unloading orifice opens from the fully closed state, it increases the difficulty of the pre-opening valve quickly balancing the pressure difference between the unloading chamber and the lower chamber of the valve disc. Furthermore, while both the pre-opening valve and the unloading orifice are essentially for adjusting the pressure in the unloading chamber, they simultaneously depressurize and pressurize the unloading chamber. This necessitates strict design of the flow area of ​​both the unloading orifice and the pre-opening valve, making pressure control in the unloading chamber difficult. An unreasonable design can lead to difficulties in quickly depressurizing when pressure relief is needed and in quickly and stably pressurizing when pressurization is required. Summary of the Invention

[0005] To overcome the shortcomings of the prior art, the present invention aims to provide a turbine regulating valve vibration reduction structure and its working method based on active control of unloading chamber pressure; the pressure of the unloading chamber is actively adjusted by an external high-pressure steam source or a high-pressure steam source at the regulating valve inlet, so as to reduce the lifting force required when the regulating valve is opened, and at the same time increase the unloading chamber pressure after the regulating valve is opened, thereby suppressing the vibration of the regulating valve.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A vibration reduction structure for a turbine regulating valve based on active pressure control of the unloading chamber includes a valve stem 1, a valve cover 2, a valve housing 3, a valve sleeve 4, a valve disc 5, and a valve seat 9. The valve disc 5 divides the internal space of the valve into an unloading chamber 6 and a lower chamber 10. The valve cover 2 is provided with a second unloading hole 17 communicating with the unloading chamber 6. The second unloading hole 17 is connected to the outlet of a high-pressure steam source through a pipeline to form a high-pressure bypass for the unloading chamber, and a loading valve 11 is provided on the high-pressure bypass pipeline of the unloading chamber. The vibration reduction structure also includes an unloading mechanism for reducing the pressure difference between the unloading chamber 6 and the lower chamber 10.

[0007] The unloading mechanism is a pre-opening valve 8 installed at the center of the valve disc 5, and the total flow cross-sectional area of ​​the second unloading hole 17 should be greater than the flow cross-sectional area of ​​the pre-opening valve 8.

[0008] The unloading mechanism includes a second unloading hole 17 connected to a low-pressure steam source inlet through a pipe to form an unloading chamber low-pressure bypass, and an unloading valve 12 is provided on the unloading chamber low-pressure bypass pipe.

[0009] The high-pressure steam source outlet is a high-pressure tapping hole 13 located on the inlet pipe of the regulating valve or on a pipe with a higher pressure than the inlet pipe of the regulating valve.

[0010] The low-pressure steam source outlet is a low-pressure tap 14 located on the outlet pipe of the regulating valve or on a pipe with a lower pressure than the outlet pressure of the regulating valve.

[0011] The valve cover 2 has several second unloading holes 17 evenly distributed along the circumference.

[0012] The high-pressure bypass pipeline of the unloading chamber is equipped with a high-pressure bypass shut-off valve located upstream and downstream of the loading valve 11; the low-pressure bypass pipeline of the unloading chamber is equipped with a low-pressure bypass shut-off valve located upstream and downstream of the unloading valve 12.

[0013] A vibration sensor and a lifting force sensor are installed on the valve stem 1 to monitor the vibration and lifting force of the valve stem 1 in real time; a pressure transmitter is installed at the outlet of the second unloading port 17 to monitor the pressure of the unloading chamber 6 in real time; the signal output terminals of the vibration sensor, the lifting force sensor and the pressure transmitter are connected to the signal input terminal of the DCS system; the signal output terminal of the DCS system is connected to the signal input terminals of the loading valve 11 and the unloading valve 12 respectively.

[0014] A working method for a turbine regulating valve vibration reduction structure based on active unloading chamber pressure control, as described above, includes: When the regulating valve is fully closed, the loading valve 11 and the pre-opening valve 8 are closed. At this time, the steam in the unloading chamber 6 mainly comes from the clearance between the valve disc 5 and the valve sleeve 4, and the pressure in the unloading chamber 6 is close to the inlet pressure of the regulating valve. When the regulating valve is opened from the fully closed state, the valve stem 1 drives the pre-opening valve 8 to open. The high-pressure steam in the unloading chamber 6 flows to the lower chamber 10 through the pre-opening valve 8 to balance the pressure difference and reduce the lifting force. When the regulating valve is opened and during the closing process, the loading valve 11 is opened and the opening degree of the loading valve 11 is adjusted so that the high-pressure steam in front of the valve enters the unloading chamber 6 through the high-pressure bypass of the unloading chamber, so that the unloading chamber 6 is in a high-pressure state and the vibration of the regulating valve is suppressed.

[0015] A working method for a turbine regulating valve vibration reduction structure based on active unloading chamber pressure control, as described above, includes: When the control valve is fully closed, the loading valve 11 and the unloading valve 12 are closed. At this time, the steam in the unloading chamber 6 mainly comes from the clearance between the valve disc 5 and the valve sleeve 4, and the pressure in the unloading chamber 6 is close to the inlet pressure of the control valve. When the control valve is opened from the fully closed state, the unloading valve 12 is opened, and the high-pressure steam in the unloading chamber 6 flows through the low-pressure bypass of the unloading chamber to the low-pressure pressure inlet 14 to balance the pressure difference and reduce the lifting force. When the control valve is opened and during the closing process, the unloading valve 12 is closed and the loading valve 11 is opened, so that the high-pressure steam in front of the valve enters the unloading chamber 6 through the high-pressure bypass of the unloading chamber, so that the unloading chamber 6 is in a high-pressure state and the vibration of the control valve is suppressed.

[0016] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention utilizes a loading valve and a pre-opening valve located on the high-pressure bypass of the unloading chamber. When the regulating valve is opened from the fully closed state, the pre-opening valve directs the high-pressure steam in the unloading chamber to the lower chamber of the valve disc, balancing the pressure difference and reducing the lifting force. When the regulating valve is opened and the operation is unstable (with significant vibration), although the presence of the pre-opening valve will release some of the pressure in the unloading chamber, the unloading chamber can still be kept under high pressure by adjusting the opening of the loading valve, thereby increasing the axial force of the valve stem and suppressing vibration.

[0017] 2. This invention achieves precise control of the unloading chamber pressure by adjusting the opening of two valves: a loading valve on the high-pressure bypass of the unloading chamber and an unloading valve on the low-pressure bypass of the unloading chamber. When the regulating valve is opened from the fully closed state, the unloading valve is opened or partially opened, connecting the unloading chamber to the low-pressure steam source, reducing the unloading chamber pressure and valve lifting force. When the operation is unstable (significant vibration) after the regulating valve is opened, the loading valve is opened or partially opened, increasing the unloading chamber pressure and the valve stem axial force, thereby suppressing vibration.

[0018] In summary, compared with existing technologies, this invention simplifies the regulating valve structure, reduces the design difficulty of the unloading port, better regulates the unloading chamber pressure, and solves the problems of excessive lifting force when the regulating valve is open and excessive vibration during partial lift, thus ensuring the safe and stable operation of the steam turbine. The structure of this invention simultaneously reduces lifting force and suppresses vibration, making it highly practical for engineering applications. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of an existing power plant steam turbine inlet regulating valve; among which... Figure 1 (a) is a schematic diagram of the control valve in the fully closed state. Figure 1 (b) is a schematic diagram of the control valve in the open state.

[0020] Figure 2 This is a schematic diagram of the vibration reduction structure of the regulating valve in Example 1.

[0021] Figure 4 This is a schematic diagram of the distribution of the second unloading hole in Example 1.

[0022] Figure 3 This is a schematic diagram of the damping structure of the regulating valve in Example 2.

[0023] In the diagram: 1. Valve stem, 2. Valve cover, 3. Valve body, 4. Valve sleeve, 5. Valve disc, 6. Unloading chamber, 7. First unloading port, 8. Pre-opening valve, 9. Valve seat, 10. Lower chamber, 11. Loading valve, 12. Unloading valve, 13. High-pressure tap port, 14. Low-pressure tap port, 15-1. High-pressure bypass shut-off valve, 15-2. High-pressure bypass shut-off valve, 16-1. Low-pressure bypass shut-off valve, 16-2. Low-pressure bypass shut-off valve, 17. Second unloading port. Detailed Implementation

[0024] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0025] like Figure 1 As shown, the existing steam inlet regulating valve for power plant turbines includes a valve stem 1, a valve cover 2, a valve body 3, a valve sleeve 4, a valve disc 5, an unloading chamber 6, a pre-opening valve 8, a valve seat 9, and a lower chamber 10. The valve sleeve 4 is provided with a first unloading hole 7. However, the first unloading hole 7 can only be continuously opened. When the regulating valve is opened from the fully closed state, it increases the difficulty for the pre-opening valve 8 to quickly balance the pressure difference between the unloading chamber 6 and the lower chamber 10 of the valve disc 5, resulting in a greater lifting force required when the regulating valve opens. The regulating valve of this invention improves upon the existing steam inlet regulating valve structure for power plant turbines. Its core lies in: eliminating the first unloading hole 7 on the valve sleeve 4 of the existing regulating valve, and providing a second unloading hole 17 on the valve cover 2, combined with a designed unloading chamber bypass system to actively regulate the pressure of the unloading chamber 6.

[0026] Example 1 like Figure 2 As shown, a turbine regulating valve vibration reduction structure based on active unloading chamber pressure control includes a valve stem 1, a valve cover 2, a valve housing 3, a valve sleeve 4, a valve disc 5, an unloading chamber 6, a pre-opening valve 8, a valve seat 9, and a lower chamber 10. The valve cover 2 is bolted to the valve housing 3 and the valve sleeve 4. The valve disc 5 is bolted to the pre-opening valve 8. The upper end of the valve stem 1 is connected to an external hydraulic actuator, and its lower end moves up and down relative to the valve disc 5 and the pre-opening valve 8. The outer circumferential surface of the valve disc 5 slides against the inner circumferential surface of the valve sleeve 4, and the valve disc 5 divides the valve's internal space into an upper unloading chamber 6 and a lower chamber 10. The pre-opening valve 8 is located within the unloading chamber 6 and is installed at the center of the valve disc 5. A second unloading hole 17 is provided on the valve cover 2. The regulating valve inlet pipe is provided with a high pressure tapping hole 13. The high pressure tapping hole 13 is connected to the second unloading hole 17 through a pipe to form a high pressure bypass of the unloading chamber. The high pressure bypass pipe of the unloading chamber is provided with a loading valve 11, which is used to regulate the steam flow rate entering the unloading chamber 6.

[0027] like Figure 3 As shown, several second unloading holes 17 are evenly distributed along the circumference on the valve cover 2, making the pressure distribution in the unloading chamber 6 more uniform. The number and diameter of the second unloading holes 17 can be changed according to different regulating valves. The total flow cross-sectional area of ​​the second unloading holes 17 should be greater than the flow cross-sectional area of ​​the pre-opening valve 8 to ensure that a stable and sufficient unloading chamber pressure can be established under any valve position.

[0028] The high-pressure bypass pipeline of the unloading chamber is also equipped with high-pressure bypass shut-off valves located upstream and downstream of the loading valve 11, namely the first high-pressure bypass shut-off valve 15-1 and the second high-pressure bypass shut-off valve 15-2. The high-pressure bypass shut-off valves are used to cut off the high-pressure bypass of the unloading chamber when the loading valve 11 fails, so as to replace and maintain the loading valve 11. Under normal operating conditions, the high-pressure bypass shut-off valves are in the normally open state.

[0029] The high-pressure tap 13 in the high-pressure bypass of the unloading chamber can also originate from a high-pressure steam source in the power plant with a pressure higher than the inlet pressure of the regulating valve, such as the main steam pipeline. The higher the steam pressure at the high-pressure tap 13, the greater the pressure regulation range of the unloading chamber 6. A vibration sensor is installed on the valve stem 1 to monitor its vibration in real time. Simultaneously, a lifting force sensor is installed at the connection between the valve stem 1 and the hydraulic actuator to monitor the lifting force of the valve stem 1 in real time. A pressure transmitter is installed at the outlet of the second unloading port 17 to monitor the pressure of the unloading chamber 6 in real time. The signals from these sensors are connected to the power plant's DCS (Distributed Control System). Furthermore, the regulation signals of the loading valve 11 and the high-pressure bypass shut-off valve are also connected to the power plant's DCS for remote control.

[0030] The operating method of the regulating valve in this embodiment 1 is as follows: When the regulating valve is fully closed, the loading valve 11 is also fully closed, and the pre-opening valve 8 is also closed. At this time, the steam in the unloading chamber 6 mainly comes from the clearance between the valve disc 5 and the valve sleeve 4. The pressure in the unloading chamber 6 is close to the inlet pressure of the regulating valve. When the regulating valve opens from the fully closed state, the valve stem 1 first drives the pre-opening valve 8 to open. The high-pressure steam in the unloading chamber 6 flows through the pre-opening valve 8 to the lower chamber 10 of the valve disc 5 to balance the pressure difference and reduce the lifting force. After the regulating valve opens, the loading valve 11 opens, allowing the high-pressure steam before the valve to enter the unloading chamber 6 through the high-pressure bypass. Simultaneously, the steam in the unloading chamber 6 flows through the pre-opening valve 8 to the lower chamber 10 of the valve disc 5. It is worth noting that the pressure in the unloading chamber 6 can be adjusted by regulating the opening degree of the loading valve 11. When the regulating valve is closed, the loading valve 11 remains open. When the valve disc 5 moves downward, the volume of the unloading chamber 6 increases. The opening of the loading valve 11 maintains the high-pressure state in the unloading chamber 6, suppressing the vibration of the regulating valve.

[0031] During the operation of the regulating valve, the vibration sensor, pressure transmitter, and lifting force sensor send the collected data to the DCS system in real time. The DCS system adjusts the opening of the loading valve 11 while monitoring the lifting force and vibration in real time. When the vibration is small and the lifting force is within a safe range, the opening is stabilized.

[0032] Example 2 like Figure 4As shown, a turbine regulating valve vibration reduction structure based on active pressure control of the unloading chamber includes a valve stem 1, a valve cover 2, a valve shell 3, a valve sleeve 4, a valve disc 5, an unloading chamber 6, a valve seat 9, a lower chamber 10, and a second unloading hole 17; a high-pressure tapping hole 13 is provided on the inlet pipe of the regulating valve, and the high-pressure tapping hole 13 is connected to the second unloading hole 17 through a pipe to form a high-pressure bypass of the unloading chamber, and a loading valve 11 is provided on the high-pressure bypass pipe of the unloading chamber. A low-pressure inlet 14 is provided on the outlet pipe of the regulating valve. The low-pressure inlet 14 is connected to the second unloading hole 17 through a pipe to form a low-pressure bypass of the unloading chamber. An unloading valve 12 is provided on the low-pressure bypass pipe of the unloading chamber. Low-pressure bypass shut-off valves located upstream and downstream of the unloading valve 12 are provided on the low-pressure bypass pipe of the unloading chamber, namely the first low-pressure bypass shut-off valve 16-1 and the second low-pressure bypass shut-off valve 16-2, which are used to cut off the low-pressure bypass of the unloading chamber when the unloading valve 12 fails, so as to replace and maintain the unloading valve 12. Under normal operating conditions, the low-pressure bypass shut-off valve is in the normally open state.

[0033] The low-pressure tap 14 can also be located at a low-pressure steam source with a lower pressure than the outlet pressure of the regulating valve, such as in the turbine exhaust pipe. The main function of the pre-opening valve 8 is to release the high-pressure steam in the unloading chamber 6 when the regulating valve is opened, thereby reducing the pressure difference between the unloading chamber 6 and the lower chamber of the valve disc 5, and thus reducing the lifting force. Therefore, after removing the pre-opening valve 8, when the regulating valve is opened from the fully closed state, the unloading valve 12 in the low-pressure bypass of the unloading chamber needs to be opened to discharge the high-pressure steam in the unloading chamber 6 to the low-pressure steam source. It should be noted that the high-pressure bypass and the low-pressure bypass of the unloading chamber will not open simultaneously. Therefore, the same second unloading port 17 can be used together, that is, the second unloading port 17 is connected to the high-pressure bypass and the low-pressure bypass of the unloading chamber through a three-way valve.

[0034] The operating method of the regulating valve in this embodiment 2 is as follows: When the regulating valve is fully closed, the loading valve 11 and unloading valve 12 are also fully closed. At this time, the steam in the unloading chamber 6 mainly comes from the clearance between the valve disc 5 and the valve sleeve 4, and the pressure in the unloading chamber 6 is close to the inlet pressure of the regulating valve. When the regulating valve opens from the fully closed state, the unloading valve 12 is opened, and the high-pressure steam in the unloading chamber 6 flows through the low-pressure bypass of the unloading chamber to the low-pressure pressure tap 14 to balance the pressure difference, reduce the pressure in the unloading chamber 6, and reduce the lifting force. When the regulating valve is opened and during the closing process, the unloading valve 12 is closed and the loading valve 11 is opened, allowing the high-pressure steam before the valve to enter the unloading chamber 6 through the high-pressure bypass of the unloading chamber, increasing the pressure in the unloading chamber 6 to suppress the vibration of the regulating valve. Similarly, the regulating signals of the unloading valve 12 and the low-pressure bypass shut-off valve are also connected to the power plant's DCS to achieve remote control.

[0035] The external bypass system piping connection of the control valve is relatively complex and has a high risk of high-temperature steam leakage. Piping integration blocks can be used to simplify the piping layout. For example, multiple second unloading holes 17 can be integrated in the valve cover 2, leaving only one interface. The piping from the second unloading hole 17 to the high-pressure tap hole 13 or the low-pressure tap hole 14 can be set in the valve body 3, and finally the second unloading hole 17 and the tap hole are connected by the integration block.

Claims

1. A vibration reduction structure for a turbine regulating valve based on active pressure control of the unloading chamber, comprising a valve stem (1), a valve cover (2), a valve shell (3), a valve sleeve (4), a valve disc (5), and a valve seat (9), wherein the valve disc (5) divides the valve interior space into an unloading chamber (6) and a lower chamber (10), characterized in that: The valve cover (2) is provided with a second unloading hole (17) that communicates with the unloading chamber (6); the second unloading hole (17) is connected to the high-pressure steam source outlet through a pipe to form a high-pressure bypass of the unloading chamber, and a loading valve (11) is provided on the high-pressure bypass pipe of the unloading chamber; the vibration reduction structure also includes an unloading mechanism for reducing the pressure difference between the unloading chamber (6) and the lower chamber (10).

2. The turbine regulating valve vibration reduction structure according to claim 1, characterized in that: The unloading mechanism is a pre-start valve (8) installed in the center of the valve disc (5), and the total flow cross-sectional area of ​​the second unloading hole (17) should be greater than the flow cross-sectional area of ​​the pre-start valve (8).

3. The turbine regulating valve vibration reduction structure according to claim 1, characterized in that: The unloading mechanism includes a second unloading hole (17) connected to the low-pressure steam source inlet through a pipeline to form an unloading chamber low-pressure bypass, and an unloading valve (12) is provided on the unloading chamber low-pressure bypass pipeline.

4. The turbine regulating valve vibration reduction structure according to claim 1, characterized in that: The high-pressure steam source outlet is a high-pressure tap hole (13) located on the inlet pipe of the regulating valve or on a pipe with a higher pressure than the inlet pressure of the regulating valve.

5. The turbine regulating valve vibration reduction structure according to claim 3, characterized in that: The low-pressure steam source outlet is a low-pressure tap (14) located on the outlet pipe of the regulating valve or on a pipe with a lower pressure than the outlet pressure of the regulating valve.

6. The turbine regulating valve vibration reduction structure according to claim 1, characterized in that: The valve cover (2) has several second unloading holes (17) evenly distributed along the circumference.

7. The turbine regulating valve vibration reduction structure according to claim 3, characterized in that: The high-pressure bypass pipeline of the unloading chamber is equipped with a high-pressure bypass shut-off valve located upstream and downstream of the loading valve (11); the low-pressure bypass pipeline of the unloading chamber is equipped with a low-pressure bypass shut-off valve located upstream and downstream of the unloading valve (12).

8. The turbine regulating valve vibration reduction structure according to claim 1, characterized in that: The valve stem (1) is equipped with a vibration sensor and a lifting force sensor for real-time monitoring of the vibration and lifting force of the valve stem (1); a pressure transmitter is installed at the outlet of the second unloading hole (17) for real-time monitoring of the pressure in the unloading chamber (6); the signal output terminals of the vibration sensor, the lifting force sensor and the pressure transmitter are connected to the signal input terminal of the DCS system; the signal output terminal of the DCS system is connected to the signal input terminals of the loading valve (11) and the unloading valve (12) respectively.

9. A method for operating the turbine regulating valve vibration reduction structure based on active pressure control of the unloading chamber as described in claim 2, characterized in that, include: When the regulating valve is fully closed, the loading valve (11) and the pre-opening valve (8) are closed. At this time, the steam in the unloading chamber (6) mainly comes from the gap between the valve disc (5) and the valve sleeve (4). The pressure in the unloading chamber (6) is close to the inlet pressure of the regulating valve. When the regulating valve is opened from the fully closed state, the valve stem (1) drives the pre-opening valve (8) to open. The high-pressure steam in the unloading chamber (6) flows to the lower chamber (10) through the pre-opening valve (8) to balance the pressure difference and reduce the lifting force. When the regulating valve is opened and during the closing process, the loading valve (11) is opened and the opening degree of the loading valve (11) is adjusted so that the high-pressure steam in front of the valve enters the unloading chamber (6) through the high-pressure bypass of the unloading chamber, so that the unloading chamber (6) is in a high-pressure state and the vibration of the regulating valve is suppressed.

10. A method for operating the turbine regulating valve vibration reduction structure based on active pressure control of the unloading chamber as described in claim 3, characterized in that, include: When the regulating valve is fully closed, the loading valve (11) and the unloading valve (12) are closed. At this time, the steam in the unloading chamber (6) mainly comes from the gap between the valve disc (5) and the valve sleeve (4). The pressure in the unloading chamber (6) is close to the inlet pressure of the regulating valve. When the regulating valve is opened from the fully closed state, the unloading valve (12) is opened. The high-pressure steam in the unloading chamber (6) flows through the low-pressure bypass of the unloading chamber to the low-pressure tap hole (14) to balance the pressure difference and reduce the lifting force. When the regulating valve is opened and during the closing process, the unloading valve (12) is closed and the loading valve (11) is opened, so that the high-pressure steam in front of the valve enters the unloading chamber (6) through the high-pressure bypass of the unloading chamber, so that the unloading chamber (6) is in a high-pressure state and the vibration of the regulating valve is suppressed.

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