A hydraulically controlled steam turbine overspeed trip valve

Abstract

The present invention discloses a hydraulically controlled steam turbine overspeed trip valve, which relates to the technical field of steam turbines. The valve comprises: a main oil pump connected to the turbine rotor and used to maintain stable system oil pressure during rotor rotation; a pressure regulating valve connected to the oil outlet pipe of the main oil pump and used to convert changes in the turbine oil pressure into changes in the displacement of the pressure regulating valve core of the pressure regulating valve; and an oil-controlled trip valve used to control whether a safety oil port is connected to a first oil return port. The safety oil port is used to accommodate safety oil, and the first oil return port is connected to an oil return tank. When the pressure regulating valve core moves to a preset displacement, the pressure regulating valve and the oil-controlled trip valve are connected, thereby connecting the safety oil port and the first oil return port. This device can effectively improve the overspeed protection effect of a steam turbine.

Description

Technical Field

[0001] The present invention relates to the technical field of steam turbines, and more particularly to a hydraulically controlled steam turbine overspeed trip valve. Background Art

[0002] In the prior art, steam turbines are rotating machines that operate at high speeds and have poor self-balancing capabilities. They must operate strictly at the rated speed. Since the rotor of a steam turbine is large in mass and rotates at a high speed of approximately 3,000 r / min to 12,000 r / min, its moment of inertia is necessarily very large. If the turbine's rotor is not controlled due to an accident, it may fly out and cause an extremely serious safety accident. For example, if the turbine's rotor is slightly overspeeded, it may cause hidden damage to the equipment, affecting its service life and posing a significant risk to its operation. If the turbine's rotor is severely overspeeded, its rotating parts will be directly and severely damaged, such as the blades and their connecting parts (belts, lacing, etc.) flying off, or the impeller and generator guard rings breaking. More serious cases may result in rotor breakage, destruction of the entire unit, and even damage to the plant and personal injury.

[0003] At present, the overspeed protection of steam turbines mainly includes the following two means:

[0004] The first method is to use a speed card to collect the turbine rotor speed and transmit it to the control system. The control system will judge the speed based on the set value. If the speed is close to the set value, an electrical signal for on-site shutdown will be sent to the solenoid valve.

[0005] The second type: The steam turbine is equipped with a mechanical fly hammer. During the rotation of the rotor, the centrifugal force will knock the fly hammer out. After being knocked out, the fly hammer will hit the emergency shut-off mechanism of the steam turbine through the lever and the electric shock. The slide valve of the emergency shut-off mechanism will move downward, thereby unloading the safety oil and braking. At this time, the steam turbine can automatically shut down.

[0006] However, the first solution suffers from a flaw: if the solenoid valve malfunctions, the function is lost. The second solution also suffers from a flaw: some turbines lack this function and rely solely on the first solution. Furthermore, the second solution suffers from the risk of the flyweight spring having poor stiffness, which could lead to accidental release or jamming of the flyweight, resulting in malfunction or failure to activate, ultimately rendering the overspeed protection ineffective.

[0007] In summary, how to improve the overspeed protection effect of a steam turbine is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0008] In view of this, an object of the present invention is to provide a hydraulically controlled steam turbine overspeed trip valve, which can effectively improve the overspeed protection effect of the steam turbine.

[0009] In order to achieve the above object, the present invention provides the following technical solutions:

[0010] A hydraulically controlled steam turbine overspeed trip valve, comprising:

[0011] A main oil pump at the shaft head is connected to the rotor of the steam turbine and is used to supply oil to the entire oil system of the steam turbine during the rotation of the rotor;

[0012] a pressure regulating valve connected to the oil outlet pipe of the shaft head main oil pump, used to convert the oil pressure change of the steam turbine into the displacement change of the pressure regulating valve core of the pressure regulating valve, and control the system oil pressure at the rated pressure through the oil unloading amount of the tapered oil port;

[0013] An oil-controlled trip valve is used to control whether the safety oil port is connected to the first oil return port. The safety oil port is used to accommodate safety oil. The first oil return port is connected to the oil return tank. When the pressure regulating valve core moves to a preset displacement, the pressure regulating valve and the oil-controlled trip valve are connected to connect the safety oil port and the first oil return port.

[0014] Preferably, the pressure regulating valve includes a pressure regulating valve body, a pressure regulating spring provided in a first cavity of the pressure regulating valve body, and the pressure regulating valve core provided in a second cavity of the pressure regulating valve body, the first cavity and the second cavity are communicated, the second cavity is provided with an oil inlet connected to the oil outlet pipe, the first cavity is provided with a second oil return port for connecting to the oil return tank, the pressure regulating valve core penetrates into the first cavity and abuts against the pressure regulating spring, and a cavity for accommodating oil is provided between the pressure regulating valve core and the oil inlet;

[0015] The second cavity is axially provided with a first interface and a second interface connected to the oil-controlled trip valve. The second interface is non-aligned with the first interface. The pressure regulating valve core includes a first blocking portion distributed in a conical shape and a second blocking portion distributed in an I-shape. The first blocking portion is located at the connection between the first cavity and the second cavity, and the second blocking portion is located between the first interface and the second interface. When the moving distance of the pressure regulating valve core is greater than or equal to the preset displacement, the first interface and the second interface are connected.

[0016] Preferably, the second cavity is provided with at least one oil drain port along the axial direction.

[0017] Preferably, the end of the pressure regulating valve is provided with a first through-hole for inserting a pressure regulating rod, the pressure regulating rod is connected to the elastic end of the pressure regulating spring, the other elastic end of the pressure regulating spring is in contact with the pressure regulating valve core, and the center lines of the pressure regulating rod, the pressure regulating spring and the pressure regulating valve core are aligned.

[0018] Preferably, the oil-controlled trip valve includes an oil-controlled valve body, an oil-controlled spring disposed in the oil-controlled valve body, and an oil-controlled valve core abutting against the oil-controlled spring; an oil inlet communicating with the second interface is provided at an end of the oil-controlled valve body, and the oil-controlled valve core is communicated with the oil inlet;

[0019] The oil control valve body is axially provided with the safety oil port and the first oil return port, the first oil return port and the safety oil port are non-aligned, the oil control valve core is distributed in an I-shape, and when the movement distance of the oil control valve core is greater than or equal to a preset distance, the first oil return port and the safety oil port are connected.

[0020] Preferably, the end of the oil-controlled trip valve is provided with a second through-hole for inserting an oil-controlled rod, the oil-controlled rod is connected to the elastic end of the oil-controlled spring, the other elastic end of the pressure-regulating spring abuts against the oil-controlled valve core, and the center lines of the oil-controlled rod, the oil-controlled spring and the oil-controlled valve core are aligned.

[0021] Preferably, the method further comprises a recovery device provided between the second interface and the oil inlet, wherein the recovery device is used to recover the oil flowing into the oil-controlled trip valve.

[0022] Preferably, the recovery device includes an oil storage tank for containing oil and a reset valve for controlling the opening and closing of the oil storage tank.

[0023] When using the hydraulically controlled steam turbine overspeed trip valve provided by the present invention, the turbine rotor continues to rotate, and oil can continuously flow into the shaft head main oil pump as the rotor rotates. To maintain the system oil pressure at the rated pressure, the pressure regulating valve can adjust the oil outlet pressure of the shaft head main oil pump. For example, when the turbine rotor speed increases to the critical speed, the oil outlet pressure of the shaft head main oil pump increases to the critical pressure. If the speed exceeds the critical speed, the rotor may fly off or break. To maintain oil pressure stability, the pressure regulating valve can convert the speed and oil pressure change signals into displacement signals for the pressure regulating valve core, causing the pressure regulating valve core of the pressure regulating valve to move to one side. When the pressure regulating valve core moves to the preset displacement, the pressure regulating valve and the oil control trip valve are connected, thereby connecting the safety oil port and the first oil return port. The safety oil in the safety oil port is connected to the oil tank, thereby quickly unloading the safety oil. Once the safety oil disappears, the steam turbine will be shut down in an emergency, ultimately achieving overspeed protection for the steam turbine. Moreover, the present solution has a simple structure and is easy to use. It can be controlled and adjusted in real time according to the actual rotation conditions of the rotor, and can provide timely and effective overspeed protection for the steam turbine.

[0024] In summary, the hydraulically controlled steam turbine overspeed trip valve provided by the present invention can effectively improve the overspeed protection effect of the steam turbine. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0026] Figure 1 This is a schematic structural diagram of the hydraulically controlled steam turbine overspeed trip valve provided by the present invention;

[0027] Figure 2 This is a partial enlarged view of the pressure regulating valve.

[0028] Figure 1 and Figure 2 middle:

[0029] 1 is the main oil pump of the shaft head, 2 is the pressure regulating valve, 21 is the pressure regulating valve body, 211 is the first cavity, 212 is the second cavity, 22 is the pressure regulating valve core, 221 is the first blocking part, 222 is the second blocking part, 23 is the oil inlet, 24 is the second oil return port, 25 is the first interface, 26 is the second interface, 27 is the oil drain port, 28 is the pressure regulating spring, 29 is the pressure regulating rod, 3 is the oil control trip valve, 31 is the safety oil port, 32 is the first oil return port, 33 is the oil control valve body, 34 is the oil control spring, 35 is the oil control valve core, 36 is the oil inlet, 37 is the oil control rod, 4 is the recovery device, 41 is the oil storage tank, and 42 is the reset valve. DETAILED DESCRIPTION

[0030] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0031] The core of the present invention is to provide a hydraulically controlled steam turbine overspeed trip valve, which can effectively improve the overspeed protection effect of the steam turbine.

[0032] Please refer to Figure 1 and Figure 2 , Figure 1 This is a schematic structural diagram of the hydraulically controlled steam turbine overspeed trip valve provided by the present invention; Figure 2 This is a partial enlarged view of the pressure regulating valve. This specific embodiment provides a hydraulically controlled steam turbine overspeed trip valve, comprising:

[0033] The main oil pump 1 of the shaft head is connected to the rotor of the steam turbine and is used to supply oil to the entire oil system of the steam turbine during the rotation of the rotor;

[0034] The pressure regulating valve 2 is connected to the oil outlet pipe of the shaft head main oil pump 1 and is used to convert the oil pressure change of the steam turbine into the displacement change of the pressure regulating valve core 22 of the pressure regulating valve 2 and control the system oil pressure at the rated pressure through the oil discharge amount of the tapered oil port;

[0035] The oil-controlled trip valve 3 is used to control whether the safety oil port 31 is connected to the first oil return port 32. The safety oil port 31 is used to accommodate safety oil, and the first oil return port 32 is connected to the oil return tank. When the pressure regulating valve core 22 moves to a preset displacement, the pressure regulating valve 2 and the oil-controlled trip valve 3 are connected to connect the safety oil port 31 and the first oil return port 32. The preset displacement is determined by the required dangerous speed value of the rotor.

[0036] During actual use, the shape, structure, size, position, etc. of the shaft head main oil pump 1, the pressure regulating valve 2 and the oil control trip valve 3 can be determined according to actual conditions and actual needs.

[0037] When the hydraulically controlled steam turbine overspeed trip valve provided by the present invention is used, the rotor of the steam turbine continues to rotate, and the oil can continuously flow into the shaft head main oil pump 1 as the rotor rotates. In order to maintain the system oil pressure at the rated pressure, the pressure regulating valve 2 can adjust the oil outlet pressure of the shaft head main oil pump 1. For example, when the rotor speed of the steam turbine increases to the critical speed, the oil outlet pressure of the shaft head main oil pump 1 increases to the critical pressure. If the speed is greater than the critical speed, the rotor may fly off or break. In order to maintain the stability of the oil pressure, the pressure regulating valve 2 can convert the speed and oil pressure change signals into the displacement signal of the pressure regulating valve core 22, so that the pressure regulating valve core 22 of the pressure regulating valve 2 moves to one side. When the pressure-regulating valve core 22 moves to a preset position, the pressure-regulating valve 2 and the oil-controlled trip valve 3 are connected, thereby connecting the safety oil port 31 and the first oil return port 32. The safety oil in the safety oil port 31 is then returned to the oil tank, rapidly draining the safety oil. Once the safety oil is depleted, the turbine is shut down, ultimately achieving overspeed protection. Furthermore, this solution features a simple structure and ease of use. It allows for real-time control and adjustment based on the actual rotor rotation, providing timely and effective overspeed protection for the turbine.

[0038] In summary, the hydraulically controlled steam turbine overspeed trip valve provided by the present invention can effectively improve the overspeed protection effect of the steam turbine.

[0039] Based on the above embodiment, preferably, the pressure regulating valve 2 includes a pressure regulating valve body 21, a pressure regulating spring 28 disposed in a first cavity 211 of the pressure regulating valve body 21, and a pressure regulating valve core 22 disposed in a second cavity 212 of the pressure regulating valve body 21. The first cavity 211 and the second cavity 212 are in communication. The second cavity 212 is provided with an oil inlet 23 connected to an oil outlet pipe. The first cavity 211 is provided with a second oil return port 24 for connecting to an oil return tank. The pressure regulating valve core 22 penetrates into the first cavity 211 and abuts against the pressure regulating spring 28. A cavity for accommodating oil is provided between the pressure regulating valve core 22 and the oil inlet 23.

[0040] The second cavity 212 is axially provided with a first interface 25 and a second interface 26 connected to the oil-controlled trip valve 3. The second interface 26 is non-aligned with the first interface 25. The pressure regulating valve core 22 includes a first blocking portion 221 distributed in a conical shape and a second blocking portion 222 distributed in an I-shape. The first blocking portion 221 is located at the connection between the first cavity 211 and the second cavity 212, and the second blocking portion 222 is located between the first interface 25 and the second interface 26. When the moving distance of the pressure regulating valve core 22 is greater than or equal to the preset displacement, the first interface 25 and the second interface 26 are connected.

[0041] It should be noted that the structure of the pressure regulating valve 2 is as follows: Figure 1 As shown, the pressure regulating valve core 22 can be configured as a special-shaped structure, which is connected to the first blocking portion 221, the first columnar structure, the trumpet-shaped structure, the second columnar structure, the I-shaped structure, and the second blocking portion 222 in sequence from left to right. A gap is provided between the first columnar structure and the second cavity 212, the second columnar structure and the second cavity 212 are arranged in a close relationship, and the protruding ends of the I-shaped structure and the second blocking portion 222 are both arranged in a close relationship with the second cavity 212. In addition, the second oil return port 24 can be provided on the side of the pressure regulating spring 28 close to the pressure regulating valve core 22.

[0042] It should also be noted that when the speed of the turbine increases, the oil pressure increases, and the oil pressure entering the cavity through the oil inlet 23 increases, which will destroy the balance between the pressure regulating valve core 22 and the pressure regulating spring 28, causing the pressure regulating valve core 22 to move to the left, and the conical structure no longer blocks the first cavity 211. The oil can enter the first cavity 211 and flow back to the return oil tank through the second return oil port 24, so that the oil pressure in the pressure regulating valve body 21 is reduced, so as to effectively regulate the oil outlet pressure of the shaft head main oil pump 1. When the turbine speed decreases, the oil pressure decreases. The oil pressure entering the cavity through the oil inlet 23 decreases, which disrupts the balance between the pressure regulating valve core 22 and the pressure regulating spring 28, causing the pressure regulating valve core 22 to move to the right. The conical structure continues to block the first cavity 211. As the oil continues to enter the cavity, the pressure in the cavity continues to increase. When the pressure increases to a value greater than the force of the pressure regulating spring 28, the pressure regulating valve core 22 can move to the left, causing the conical structure to no longer block the first cavity 211. The oil enters the first cavity 211 and flows back to the oil return tank through the second oil return port 24, thereby reducing the oil pressure in the pressure regulating valve body 21 and effectively regulating the oil output pressure of the shaft head main oil pump 1. In other words, this device converts the oil pressure change caused by the change in rotor speed into the displacement change of the pressure regulating valve core 22. The oil pressure is regulated by the movement of the pressure regulating valve core 22, and overspeed protection of the turbine can be achieved.

[0043] Preferably, the second cavity 212 is provided with at least one oil drain port 27 along the axial direction. When the pressure regulating valve core 22 moves left and right in response to changes in oil pressure, the recessed portion of the pressure regulating valve core 22 moves to the oil drain port 27, enabling an oil drain operation to discharge the high-pressure oil in the pressure regulating valve core 22 and the second cavity 212, thereby achieving the purpose of reducing pressure.

[0044] Preferably, the end of the pressure regulating valve 2 is provided with a first through-hole for inserting the pressure regulating rod 29, the pressure regulating rod 29 is connected to the elastic end of the pressure regulating spring 28, the other elastic end of the pressure regulating spring 28 is in contact with the pressure regulating valve core 22, and the center lines of the pressure regulating rod 29, the pressure regulating spring 28 and the pressure regulating valve core 22 are aligned.

[0045] It should be noted that the pressure regulating valve 2 is connected in parallel to the oil outlet pipeline of the turbine's main oil pump 1. It regulates the system oil pressure and provides overpressure protection, thereby maintaining a constant system oil pressure. The pressure regulating rod 29 is primarily used to adjust the operating value of the pressure regulating valve 2. Specifically, by controlling the movement of the pressure regulating rod 29, the displacement of the pressure regulating valve core 22 can be accurately controlled.

[0046] Based on the above embodiment, preferably, the oil-controlled trip valve 3 includes an oil-controlled valve body 33, an oil-controlled spring 34 disposed in the oil-controlled valve body 33, and an oil-controlled valve core 35 abutting against the oil-controlled spring 34. An oil inlet 36 communicating with the second interface 26 is provided at the end of the oil-controlled valve body 33, and the oil-controlled valve core 35 is in communication with the oil inlet 36.

[0047] The oil control valve body 33 is axially provided with a safety oil port 31 and a first oil return port 32. The first oil return port 32 and the safety oil port 31 are not aligned, and the oil control valve core 35 is distributed in an I-shape. When the movement distance of the oil control valve core 35 is greater than or equal to a preset distance, the first oil return port 32 and the safety oil port 31 are connected.

[0048] It should be noted that when the first port 25 and the second port 26 are connected, oil can flow through the first port 25 into the second port 26, and then from the second port 26 to the oil inlet 36 of the oil-controlled trip valve 3. As the oil flows into the oil-controlled trip valve 3, the oil-controlled valve core 35 moves to the left under the action of oil pressure. When the leftward movement of the oil-controlled valve core 35 is greater than or equal to a preset distance, the first oil return port 32 connects with the safety oil port 31, rapidly unloading the safety oil, thereby causing an emergency shutdown of the steam turbine. If no oil flows into the oil-controlled trip valve 3, the rapid unloading of the safety oil and the emergency shutdown of the steam turbine will not occur.

[0049] Preferably, a second through-hole for inserting an oil control rod 37 is provided at the end of the oil-controlled trip valve 3. The oil control rod 37 is connected to the elastic end of the oil control spring 34. The other elastic end of the pressure-regulating spring 28 abuts against the oil control valve core 35. The centerlines of the oil control rod 37, oil control spring 34, and oil control valve core 35 are aligned. By controlling the movement of the oil control rod 37, the displacement of the oil control valve core 35 can be accurately controlled, thereby controlling the connection between the safety oil port 31 and the first oil return port 32.

[0050] It should be further explained that when the turbine speed increases, the outlet oil pressure of the main oil pump 1 changes. To maintain the stability of the system oil pressure, the pressure regulating valve core 22 of the pressure regulating valve 2 moves to the left. At this time, the outlet oil of the main oil pump 1 can connect to the second oil return port 24 through the conical surface of the pressure regulating valve core 22. The higher the rotor speed and the greater the displacement of the pressure regulating valve core 22, the greater the oil discharge volume. This process converts the speed signal into the displacement signal of the pressure regulating valve core 22.

[0051] Furthermore, the first and second ports 25, 26 on the right end of the pressure-regulating valve core 22 are connected to the lowest end of the oil-controlled trip valve 3. Within the permissible rotor speed range, the first and second ports 25, 26 are disconnected. If the rotor's critical speed is set to nr / min, the output oil pressure signal corresponding to this speed will correspond to a displacement signal. Under this displacement, the pressure-regulating valve core 22 moves leftward until the first and second ports 25, 26 are connected. At this point, oil can flow through the second port 26 into the right chamber of the oil-controlled trip valve 3. The oil-controlled valve core 35 can then be rapidly moved leftward, connecting the safety oil port 31 to the first oil return port 32. This allows the safety oil to be quickly discharged, causing the turbine to shut down urgently and achieving overspeed protection.

[0052] Preferably, the system further includes a recovery device 4 disposed between the second interface 26 and the oil inlet 36. The recovery device 4 is used to recover the oil flowing into the oil-controlled trip valve 3. The recovery device 4 is activated when the unit meets the startup conditions again, so that the oil control valve core 35 of the oil-controlled trip valve 3 can be reset under the action of the oil control spring 34, allowing safety oil to be re-input into the safety oil port 31, thereby facilitating the restart of the steam turbine.

[0053] Preferably, the recovery device 4 includes an oil storage tank 41 for containing oil and a reset valve 42 for controlling the opening and closing of the oil storage tank 41. Therefore, when it is necessary to recover the oil in the oil-controlled trip valve 3, the reset valve 42 located between the oil inlet 36 and the oil storage tank 41 can be opened, and the oil control spring 34 can push the oil control valve core 35 to the right, thereby pushing the oil out. Finally, the oil can flow into the oil storage tank 41, so that the oil control valve core 35 returns to its initial state. At this time, safety oil can be re-injected into the safety oil port 31 to facilitate restarting the turbine. Among them, the oil storage tank 41 can be configured as a return oil tank, that is, after passing through the reset valve 42, the oil can flow back to the return oil tank. Of course, the oil storage tank 41 can also be configured as other box structures.

[0054] It should be noted that the first interface 25 and the second interface 26, the first perforation and the second perforation, the first oil return port 32 and the second oil return port 24, the first cavity 211 and the second cavity 212, the first blocking portion 221 and the second blocking portion 222 mentioned in this application document, where the first and the second are for distinguishing the different positions, and there is no order of precedence.

[0055] In addition, it should be noted that the directions or positional relationships indicated by "left and right" and the like in this application are based on the directions or positional relationships shown in the accompanying drawings and are only for the purpose of simplifying the description and facilitating understanding. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limiting the present invention.

[0056] The various embodiments in this specification are described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the various embodiments can be referenced to each other. Any combination of all the embodiments provided by the present invention is within the scope of protection of this invention and will not be described in detail here.

[0057] The above describes in detail the hydraulically controlled steam turbine overspeed trip valve provided by the present invention. This article uses specific examples to illustrate the principles and implementation methods of the present invention. The description of the above examples is intended only to facilitate understanding of the method and core concepts of the present invention. It should be noted that those skilled in the art may make various improvements and modifications to the present invention without departing from the principles of the present invention, and such improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A hydraulically controlled steam turbine overspeed trip valve, characterized in that: include: A main oil pump (1) at the shaft head is connected to the rotor of the steam turbine and is used to supply oil to the entire oil system of the steam turbine during the rotation of the rotor; A pressure regulating valve (2) connected to the oil outlet pipe of the shaft head main oil pump (1) is used to convert the oil pressure change of the steam turbine into the displacement change of the pressure regulating valve core (22) of the pressure regulating valve (2) and control the system oil pressure at the rated pressure through the oil discharge amount of the tapered oil port; an oil-controlled trip valve (3) for controlling whether a safety oil port (31) is connected to a first oil return port (32), wherein the safety oil port (31) is used to accommodate safety oil, and the first oil return port (32) is connected to an oil return tank; when the pressure regulating valve core (22) moves to a preset displacement, the pressure regulating valve (2) and the oil-controlled trip valve (3) are connected, so that the safety oil port (31) and the first oil return port (32) are connected; The pressure regulating valve (2) comprises a pressure regulating valve body (21), a pressure regulating spring (28) arranged in a first cavity (211) of the pressure regulating valve body (21), and the pressure regulating valve core (22) arranged in a second cavity (212) of the pressure regulating valve body (21), wherein the first cavity (211) and the second cavity (212) are in communication, the second cavity (212) is provided with an oil inlet (23) connected to the oil outlet pipe, and the first cavity (211) is provided with a spring for connecting to the oil outlet pipe. The second oil return port (24) of the oil return tank, the pressure regulating valve core (22) penetrates into the first cavity (211) and abuts against the pressure regulating spring (28), and a cavity for accommodating oil is provided between the pressure regulating valve core (22) and the oil inlet (23); the second cavity (212) is axially provided with a first interface (25) and a second interface (26) connected to the oil control trip valve (3), the second interface (26) and the first interface (25) are arranged non-aligned, and the pressure regulating valve core (22) is provided with a pressure regulating spring (28). The pressure regulating valve core (22) comprises a first blocking portion (221) distributed in a conical shape and a second blocking portion (222) distributed in an I-shape, wherein the first blocking portion (221) is located at the connection point between the first cavity (211) and the second cavity (212), and the second blocking portion (222) is located between the first interface (25) and the second interface (26). When the movement distance of the pressure regulating valve core (22) is greater than or equal to the preset displacement, the first interface (25) and the second interface (26) are connected. The two interfaces (26) are connected; the second cavity (212) is provided with at least one oil drain port (27) along the axial direction; the end of the pressure regulating valve (2) is provided with a first through hole for inserting a pressure regulating rod (29); the pressure regulating rod (29) is connected to the elastic end of the pressure regulating spring (28); the other elastic end of the pressure regulating spring (28) is in contact with the pressure regulating valve core (22), and the center lines of the pressure regulating rod (29), the pressure regulating spring (28) and the pressure regulating valve core (22) are aligned.

2. The hydraulically controlled steam turbine overspeed trip valve according to claim 1, characterized in that: The oil-controlled trip valve (3) comprises an oil-controlled valve body (33), an oil-controlled spring (34) disposed in the oil-controlled valve body (33), and an oil-controlled valve core (35) abutting against the oil-controlled spring (34); an end portion of the oil-controlled valve body (33) is provided with an oil inlet (36) communicating with the second interface (26); the oil-controlled valve core (35) is in communication with the oil inlet (36); The oil control valve body (33) is provided with the safety oil port (31) and the first oil return port (32) along the axial direction. The first oil return port (32) and the safety oil port (31) are arranged non-aligned. The oil control valve core (35) is distributed in an I-shaped manner. When the movement distance of the oil control valve core (35) is greater than or equal to a preset distance, the first oil return port (32) and the safety oil port (31) are communicated.

3. The hydraulically controlled steam turbine overspeed trip valve according to claim 2, characterized in that: The end of the oil-controlled trip valve (3) is provided with a second through-hole for inserting an oil-controlled rod (37), the oil-controlled rod (37) is connected to the elastic end of the oil-controlled spring (34), the other elastic end of the pressure-regulating spring (28) is in contact with the oil-controlled valve core (35), and the center lines of the oil-controlled rod (37), the oil-controlled spring (34) and the oil-controlled valve core (35) are aligned.

4. The hydraulically controlled steam turbine overspeed trip valve according to claim 1, characterized in that: It also includes a recovery device (4) provided between the second interface (26) and the oil inlet (36), the recovery device (4) being used to recover the oil flowing into the oil-controlled trip valve (3).

5. The hydraulically controlled steam turbine overspeed trip valve according to claim 4, characterized in that: The recovery device (4) comprises an oil storage tank (41) for containing oil and a reset valve (42) for controlling the opening and closing of the oil storage tank (41).

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