Novel adjustable mechanical reset hydraulic control valve

Abstract

This invention discloses a novel adjustable mechanical reset hydraulic control valve, comprising an integrated valve block assembly, a manual directional valve, an adjustable hydraulic control directional valve, a shut-off valve, an external safety oil connector, an external pressure-free return oil connector, and a vertical mounting bracket. This solution optimizes the turbine safety oil circuit control structure from multiple dimensions, including operational safety, operating condition adaptability, installation and maintenance, local control, and spatial arrangement. It eliminates unit safety hazards caused by electrical malfunctions through forced secondary confirmation of the oil circuit, broadens the equipment's applicability through an adjustable oil pressure structure, and simplifies on-site installation and maintenance through a highly integrated design. Overall reliability and practicality are comprehensively improved compared to traditional single-valve control solutions.

Description

Technical Field

[0001] This invention relates to the field of steam turbine EH hydraulic control technology, specifically to a novel adjustable mechanical reset hydraulic control valve. Background Technology

[0002] In the safety oil circuit of the turbine EH control system, the unit's tripping and tripping operations rely on the establishment and release of safety oil pressure. Traditional control schemes only equip a manual directional valve on the safety oil line to complete the local tripping and tripping actions. This manual directional valve has a P inlet, a T return port, and A and B working ports, and switches the safety oil circuit on and off through the valve core. The system's remote electrical safety device can remotely perform tripping operations. Under normal operating conditions, the safety oil pressure can be established without on-site personnel intervention. The entire oil circuit relies on a single directional valve to complete the safety oil on / off control, without a matching local reset auxiliary valve group structure. The hydraulic components related to hydraulic pressure regulation and secondary confirmation are not integrated into the safety oil line.

[0003] The existing single manual directional valve control circuit lacks a secondary safety confirmation function on site. When the manual directional valve is held in the engaged position, the remote electrical device is prone to accidental activation of the engaged position. Without manual verification and confirmation by on-site personnel, the safety oil is directly established, posing a safety hazard of unit malfunction. The traditional solution does not have a matching adjustable hydraulic directional valve and shut-off valve combination reset oil circuit, making it impossible to set a pressure threshold for the establishment of safety oil pressure, and unable to force manual confirmation by blocking the oil circuit pressure relief channel through local operation. At the same time, the functional valves are arranged separately and rely on external steel pipes for connection, resulting in many leakage points, complicated installation and maintenance procedures, and the hydraulic valve activation trigger oil pressure cannot be flexibly adjusted according to different unit operating conditions, resulting in poor adaptability.

[0004] Therefore, a solution is needed. Summary of the Invention

[0005] (a) Technical problems to be solved To address the shortcomings of existing technologies, this invention provides a novel adjustable mechanical reset hydraulic control valve to solve the problems mentioned in the background section.

[0006] (II) Technical Solution To achieve the above objectives, the present invention provides the following technical solution: A novel adjustable mechanical reset hydraulic control valve includes an integrated valve block assembly, a manual directional valve, an adjustable hydraulic directional valve, a shut-off valve, a safety oil external connector, a pressureless return oil external connector, and a vertical mounting bracket. The integrated valve block assembly is rigidly fixed to the top of the vertical mounting bracket. The adjustable hydraulic directional valve and the manual directional valve are arranged side-by-side on the upper surface of the integrated valve block assembly. The shut-off valve and the safety oil external connector are respectively installed on the left and right sidewalls of the integrated valve block assembly. The pressureless return oil external connector is located on the left end of the front sidewall of the integrated valve block assembly. The integrated valve block assembly 1 has interconnected internal flow channels cast inside to achieve communication between the oil ports of each valve component. The front end of the manual reversing valve 2 is provided with an exposed manual operating handle 21. The manual reversing valve 2 has an oil inlet P, an oil return T, a working oil port A and a working oil port B. The oil inlet P is connected to the internal flow channel of the safety oil external connector 5, and the oil return T is connected to the internal flow channel of the pressureless oil return external connector 6. The adjustable hydraulic directional valve 3 has an adjustable spring valve core assembly 31 built in it. The preload of the adjustable spring valve core assembly 31 can be adjusted externally to set the valve core switching trigger oil pressure. The adjustable hydraulic directional valve 3 has P port, T port, A port and B port inside. The control oil chamber of the adjustable hydraulic directional valve 3 is connected to the oil passage of the shut-off valve 4. The shut-off valve 4 is a manually operated hydraulic shut-off valve. The shut-off valve 4 has an oil inlet P, an oil outlet A, and an oil return B. The oil inlet P is connected to the control oil chamber flow channel of the adjustable hydraulic directional valve 3.

[0007] Preferably, the vertical mounting bracket 7 includes a square base plate 71 and a vertical support column 72; the square base plate 71 has four Φ13 mounting through holes at its four corners, and the lower end of the support column 72 is fixedly connected to the center of the square base plate 71.

[0008] Preferably, the safety oil external connector 5 has a specification of Φ19 and is used to connect to the safety oil pipe of the turbine EH system; the pressureless return oil external connector 6 has a specification of Φ25 and is used to connect to the pressureless return oil pipeline of the system DV; both the safety oil external connector 5 and the pressureless return oil external connector 6 adopt a threaded sealing structure, and the safety oil external connector 5 and the pressureless return oil external connector 6 are independent of each other and have no interconnection or cross-flow channels.

[0009] Preferably, the manual reversing valve 2 has two working positions: engaging and disengaging. When the manual operating handle 21 is moved upward to the engaging position, safety oil enters the internal flow channel of the valve group through the P oil inlet. When the manual operating handle 21 is moved downward to the disengaging position, safety oil is directly depressurized and returned to the turbine through the T return oil port and the pressureless return oil external connector 6, thereby realizing on-site manual disengagement and depressurization of the turbine.

[0010] Preferably, the adjustable hydraulic directional valve 3 and the shut-off valve 4 are connected in series through the internal flow channel of the integrated valve block assembly 1 to form a secondary safety confirmation and reset oil circuit. When only remote electrical equipment performs the tripping operation, the safety oil circuit cannot establish pressure, and the turbine valves cannot operate. The shut-off valve 4 must be manually closed on-site to cut off the return oil pressure relief channel of the B return port of the shut-off valve 4. The safety oil pressure gradually increases. When the oil pressure exceeds the preset pressure value of the adjustable spring valve core assembly 31, the valve core inside the adjustable hydraulic directional valve 3 reverses and resets, the oil circuit is fully open, and the system can establish a stable safety oil circuit.

[0011] Preferably, once the system's safe oil pressure is fully established and the turbine is ready for operation, the on-site operator manually opens the shut-off valve 4, opens the B return oil port of the shut-off valve 4, releases the oil pressure inside the control oil chamber of the adjustable hydraulic directional valve 3, releases the valve core oil pressure lock-up state, and keeps the oil circuit continuously open during normal unit operation.

[0012] Preferably, the adjustable spring valve core assembly 31 is externally equipped with an adjusting screw, a preload spring, and a spring limit seat; the adjusting screw is exposed on the outside of the adjustable hydraulic control directional valve 3 body, and rotating the adjusting screw can change the compression of the preload spring, which can continuously adjust the trigger oil pressure required for the valve core switching of the adjustable hydraulic control directional valve 3, adapting to the oil pressure parameter requirements of different unit EH systems.

[0013] Preferably, the integrated valve block assembly 1 is a one-piece hydraulic integrated block structure. The manual directional valve 2, the adjustable hydraulic directional valve 3, and the shut-off valve 4 are all directly stacked and installed on the integrated valve block assembly 1. The oil circuit of each valve is connected by the prefabricated flow channel inside the valve block assembly 1, without the need for external transition oil pipes, thus reducing pipeline leakage points.

[0014] Preferably, the entire valve assembly is connected to the turbine EH system pipeline only through two pipelines: the safety oil external connector 5 and the unpressurized return oil external connector 6. The whole assembly is an independent complete set of components, which can be hoisted and disassembled as a whole, making on-site installation, subsequent maintenance, and valve replacement operations simple.

[0015] Preferably, the valve assembly of the novel adjustable mechanical reset hydraulic control valve is installed in series on the safety oil circuit of the turbine EH system. After the unit trips and depressurizes, the safety oil pressure cannot be restored by simply engaging the remote electrical device alone. On-site personnel must be forced to operate the shut-off valve 4 to complete a manual secondary confirmation, thereby avoiding turbine safety accidents caused by the remote electrical device's accidental engagement of the valve from the perspective of the hydraulic circuit structure.

[0016] (III) Beneficial Effects This invention provides a novel adjustable mechanical reset hydraulic control valve. It has the following beneficial effects: 1. The integrated valve block assembly is equipped with a manual directional valve, an adjustable hydraulic directional valve, and a shut-off valve to form a secondary confirmation oil circuit. Manual operation of the shut-off valve is required to raise the oil pressure and trigger the adjustable spring valve core assembly to open the oil circuit, which can completely prevent turbine safety accidents caused by remote electrical accidental circuit breaker activation.

[0017] 2. The adjustable hydraulic control directional valve has a built-in adjustable spring valve core assembly, which can continuously adjust the valve core trigger oil pressure. It is equipped with a safety oil external connector that does not cross-contaminate oil and a pressureless return oil external connector, which can adapt to the oil pressure conditions of different models of steam turbine EH system.

[0018] 3. The integrated valve block assembly eliminates the need for external transition oil pipes, reducing leakage points. The entire valve group relies solely on the safety oil external connector and the pressureless return oil external connector docking system. With the help of a vertical mounting bracket, it can be hoisted as a whole, making installation, maintenance, and valve replacement operations simple.

[0019] 4. The manual reversing valve is equipped with a manual operating handle, which can be used to engage the brake and perform emergency tripping and pressure relief on the spot. The shut-off valve can be manually opened and closed to control the oil circuit. The combination of the two manual mechanisms enhances the flexibility and reliability of the unit's on-site start-up and shutdown and emergency handling.

[0020] 5. The manual directional valve, adjustable hydraulic directional valve, and shut-off valve are compactly arranged on the integrated valve block assembly. The vertical mounting bracket includes a square base plate with mounting holes. The overall size is small and suitable for the narrow pipeline layout space at the turbine site. Attached Figure Description

[0021] Figure 1 This is a front view and a three-dimensional structural diagram of the overall appearance of the present invention.

[0022] Figure 2 This is a three-dimensional structural diagram of the appearance of the present invention.

[0023] 1-Integrated valve block assembly; 2-Manual directional valve; 21-Exposed manual operating handle; 3-Adjustable hydraulic directional valve; 31-Adjustable spring valve core assembly; 4-Stop valve; 5-Safety oil external connector; 6-Unpressurized return oil external connector; 7-Vertical mounting bracket; 71-Square base plate; 72-Vertical support column. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Please see Figure 1-2This invention provides a technical solution that includes an integrated valve block assembly 1, a manual directional valve 2, an adjustable hydraulic directional valve 3, a shut-off valve 4, a safety oil external connector 5, a pressureless return oil external connector 6, and a vertical mounting bracket 7. The integrated valve block assembly 1 is rigidly fixed to the top of the vertical mounting bracket 7. The adjustable hydraulic directional valve 3 and the manual directional valve 2 are arranged side by side on the upper surface of the integrated valve block assembly 1. The shut-off valve 4 and the safety oil external connector 5 are respectively installed on the left and right side walls of the integrated valve block assembly 1. The pressureless return oil external connector 6 is located on the left end of the front side wall of the integrated valve block assembly 1. The integrated valve block assembly 1 has interconnected internal flow channels cast inside to achieve communication between the oil ports of each valve component. The front end of the manual reversing valve 2 is provided with an exposed manual operating handle 21. The manual reversing valve 2 has an oil inlet P, an oil return T, a working oil port A and a working oil port B. The oil inlet P is connected to the internal flow channel of the safety oil external connector 5, and the oil return T is connected to the internal flow channel of the pressureless oil return external connector 6. The adjustable hydraulic directional valve 3 has an adjustable spring valve core assembly 31 built in. The preload of the adjustable spring valve core assembly 31 can be adjusted externally to set the valve core switching trigger oil pressure. The adjustable hydraulic directional valve 3 has P port, T port, A port and B port inside. The control oil chamber of the adjustable hydraulic directional valve 3 is connected to the oil passage of the shut-off valve 4. The shut-off valve 4 is a manually operated hydraulic shut-off valve. The shut-off valve 4 has an oil inlet (P), an outlet (A), and a return port (B) inside. The oil inlet (P) is connected to the adjustable hydraulic directional valve 3 to control the flow path of the oil chamber.

[0026] In detail, the vertical mounting bracket 7 includes a square base plate 71 and a vertical support column 72; the square base plate 71 has four Φ13 mounting through holes at its four corners, and the lower end of the support column 72 is fixedly connected to the center of the square base plate 71.

[0027] The safety oil external connector 5 has a specification of Φ19 and is used to connect to the safety oil pipe of the turbine EH system; the unpressurized return oil external connector 6 has a specification of Φ25 and is used to connect to the unpressurized return oil pipeline of the system DV; both the safety oil external connector 5 and the unpressurized return oil external connector 6 adopt a threaded sealing structure, and the safety oil external connector 5 and the unpressurized return oil external connector 6 are independent of each other and have no interconnection or oil leakage channels.

[0028] The manual reversing valve 2 has two working positions: brake engagement and brake disengagement. When the manual operating handle 21 is moved upward to switch to the brake engagement position, safety oil enters the internal flow channel of the valve group through the P oil inlet. When the manual operating handle 21 is moved downward to switch to the brake disengagement position, safety oil is directly depressurized and returned to the turbine through the T oil return port and the pressure-free return oil external connector 6, thereby realizing local manual brake disengagement and pressure relief of the turbine.

[0029] The adjustable hydraulic directional valve 3 and the shut-off valve 4 are connected in series through the internal flow channel of the integrated valve block assembly 1 to form a secondary safety confirmation and reset oil circuit. When only the remote electrical system performs the tripping operation, the safety oil circuit cannot establish pressure, and the turbine valves cannot operate. The shut-off valve 4 must be manually closed on-site to cut off the return oil pressure relief channel of the B return port of the shut-off valve 4. The safety oil pressure gradually increases. When the oil pressure exceeds the preset pressure value of the adjustable spring valve core assembly 31, the valve core inside the adjustable hydraulic directional valve 3 reverses and resets, the oil circuit is fully open, and the system can establish a stable safety oil circuit.

[0030] Once the system's safe oil pressure is fully established and the turbine is ready for operation, the on-site operator manually opens the shut-off valve 4, opens the B return oil port of the shut-off valve 4, releases the oil pressure inside the control oil chamber of the adjustable hydraulic directional valve 3, and releases the valve core oil pressure lock-up state. During normal operation of the unit, the oil circuit remains continuously open.

[0031] The adjustable spring valve core assembly 31 has an external pressure adjusting screw, a preload spring, and a spring limit seat. The pressure adjusting screw is exposed on the outside of the adjustable hydraulic control directional valve 3 body. Rotating the pressure adjusting screw can change the compression of the preload spring, and can continuously adjust the trigger oil pressure required for the valve core of the adjustable hydraulic control directional valve 3 to adapt to the oil pressure parameter requirements of different unit EH systems.

[0032] The integrated valve block assembly 1 is a one-piece hydraulic integrated block structure. The manual directional valve 2, the adjustable hydraulic directional valve 3, and the shut-off valve 4 are all directly stacked and installed on the integrated valve block assembly 1. The oil circuit of each valve is connected by the prefabricated flow channel inside the valve block assembly 1, without the need for external transition oil pipes, thus reducing pipeline leakage points.

[0033] The entire valve assembly is connected to the turbine EH system pipeline only through two pipelines: the safety oil external connector 5 and the unpressurized return oil external connector 6. It is an independent complete set of components, which can be hoisted and disassembled as a whole, making on-site installation, subsequent maintenance, and valve replacement operations simple.

[0034] A novel adjustable mechanical reset hydraulic control valve assembly is installed in series on the safety oil circuit of the turbine EH system. After the unit trips and depressurizes, the safety oil pressure cannot be restored by simply engaging the remote electrical device alone. On-site personnel must be forced to manually confirm the operation of the shut-off valve 4 on-site. This avoids turbine safety accidents caused by the remote electrical device's accidental engagement of the valve from the perspective of the hydraulic circuit structure.

[0035] Solution Analysis: 1. Significant safety protection effect, avoiding the risk of unit malfunction. This solution integrates the manual directional valve 2, the adjustable hydraulic directional valve 3, and the shut-off valve 4 onto the integrated valve block assembly 1 to form a secondary safety confirmation oil circuit. After the unit trips and depressurizes, relying solely on remote electrical equipment to engage the switch cannot establish a safe oil pressure. On-site personnel must operate the shut-off valve 4 locally to close the B return port of the shut-off valve 4, cutting off the pressure relief channel. Only after raising the oil pressure to the preset pressure of the adjustable spring valve core assembly 31 can the adjustable hydraulic directional valve 3 reset and conduct the oil circuit to establish a safe oil pressure, thus forcing manual secondary verification. This eliminates turbine safety accidents caused by accidental remote electrical equipment engagement at the hydraulic circuit level and makes up for the lack of a safety confirmation process in traditional single-valve control.

[0036] 2. The hydraulic pressure parameters are highly adaptable and can be adapted to various types of steam turbine units. The adjustable hydraulic control directional valve 3 is internally equipped with an adjustable spring valve core assembly 31. The adjustable spring valve core assembly 31 has an adjusting screw on its outer side. Rotating the adjusting screw can change the compression of the internal preload spring, which can continuously and steplessly adjust the valve core switching trigger oil pressure of the adjustable hydraulic control directional valve 3. It is equipped with a Φ19 safety oil external connector 5 and a Φ25 pressureless return oil external connector 6. The oil circuits of the two sets of connectors are independent and there is no oil cross-contamination. It can be matched with the oil pressure conditions of different models of steam turbine EH systems, and the equipment versatility is greatly improved.

[0037] 3. The integrated structure reduces the risk of leakage and facilitates equipment operation and maintenance. The integrated valve block assembly 1 is a one-piece hydraulic integrated block structure. The manual directional valve 2, adjustable hydraulic directional valve 3, and shut-off valve 4 are all directly stacked and installed on the surface of the integrated valve block assembly 1. All oil ports are connected by the pre-fabricated interconnecting internal flow channels of the integrated valve block assembly 1, eliminating the need for external transition oil pipes required by traditional split valve components and significantly reducing the number of hydraulic seal leakage points. The entire valve group is connected to the turbine system through only two pipelines: the safety oil external connector 5 and the pressureless return oil external connector 6. The whole is an independent complete set of components. It is equipped with a vertical mounting bracket 7 with a square base plate 71 and a vertical support column 72, which can be hoisted and disassembled as a whole. The on-site installation, subsequent maintenance, and valve replacement operation process is simple, reducing the workload of on-site operation and maintenance.

[0038] 4. It has complete local operation functions, and the unit's emergency response is flexible and reliable. The manual reversing valve 2 is equipped with an exposed manual operating handle 21 at the front end, which has two stable working positions: brake engagement and brake disengagement. Pushing the manual operating handle 21 upwards can complete the local brake engagement and pressure building, while pushing it downwards can quickly release the safety oil through the T return oil port via the unpressurized return oil external connector 6, realizing local manual emergency brake disengagement and shutdown. The shut-off valve 4 has an independent manual on / off structure, which can flexibly control the oil chamber and oil circuit under different operating conditions such as unit startup and maintenance. The two manual operating mechanisms work together to make the local emergency handling and start-up and shutdown operations of the steam turbine more stable and controllable.

[0039] 5. Compact structure with small footprint, suitable for confined site piping space. The vertical mounting bracket 7 has a regular overall structural size. The square base plate 71 has four Φ13 mounting holes at the four corners for easy on-site fixing. The manual reversing valve 2 and the adjustable hydraulic reversing valve 3 are arranged side by side on the integrated valve block assembly 1. The shut-off valve 4 is mounted on the side wall of the integrated valve block assembly 1. All components are closely arranged without any extra external pipelines. The overall size is small and can be adapted to the narrow pipeline layout space of the steam turbine EH system, reducing the difficulty of on-site pipeline layout modification.

[0040] Working principle: During normal operation of the steam turbine unit, this novel adjustable mechanical reset hydraulic control valve is fixed as a whole by the vertical mounting bracket 7. The integrated valve block assembly 1 has internal interconnected flow channels that connect all components. Safety oil enters the P inlet of the manual directional valve 2 through the Φ19 safety oil external connector 5, and pressureless return oil flows back from the T return port of the manual directional valve 2 through the Φ25 pressureless return oil external connector 6. By pushing the exposed manual operating handle 21 at the front end of the manual directional valve 2 upwards, it switches to the brake-on operation mode. In the first position, safety oil is supplied to the adjustable hydraulic directional valve 3 circuit through the A and B working ports of the manual directional valve 2. Moving the manual operating handle 21 downwards to the trip position directly releases the safety oil, achieving local shutdown. When the unit trips and depressurizes, even if the remote electrical system performs a tripping operation, the safety oil circuit cannot build up pressure. The operator must locally close the stop valve 4 mounted on the side wall of the integrated valve block assembly 1, cutting off the pressure relief channel of the B return port of the stop valve 4. The safety oil pressure continues to rise and enters the adjustable hydraulic directional valve circuit. The control oil chamber of valve 3 allows for adjustment of the preload spring compression by rotating the adjustable spring valve core assembly 31, which is exposed on the valve body of the adjustable hydraulic directional valve 3. This sets the valve core switching trigger oil pressure. When the oil pressure exceeds the preset pressure threshold of the adjustable spring valve core assembly 31, the valve core inside the adjustable hydraulic directional valve 3 resets, and its internal P, T, A, and B ports are fully connected, establishing a stable and safe oil supply for the system. After the oil pressure reaches the target and the unit is ready for operation, the shut-off valve is manually opened. 4. The adjustable hydraulic directional valve 3 is opened through its B return oil port to control the oil pressure inside the oil chamber, maintaining the continuous conduction of the oil circuit to ensure the operation of the unit; the entire set of manual directional valve 2, adjustable hydraulic directional valve 3, and shut-off valve 4 are integrated and assembled on the integrated valve block assembly 1. No external transition oil pipe is required. It only relies on two pipelines, the safety oil external connector 5 and the pressureless return oil external connector 6, to connect to the turbine EH system. The oil circuit structure forces on-site manual secondary safety confirmation, eliminating the safety hazards caused by remote electrical accidental activation.

[0041] Technical effects of implementing this solution: This solution optimizes the turbine safety oil circuit control structure from multiple dimensions, including operational safety, operating condition adaptability, installation and maintenance, local control, and spatial layout. It eliminates the unit safety hazards caused by electrical malfunctions by forcibly confirming the oil circuit, expands the equipment's applicability by relying on the adjustable oil pressure structure, and simplifies on-site installation and maintenance by relying on highly integrated design. Overall reliability and practicality are comprehensively improved compared to traditional single-valve control solutions.

[0042] The present invention comprises: 1-integrated valve block assembly; 2-manual directional valve; 21-exposed manual operating handle; 3-adjustable hydraulic directional valve; 31-adjustable spring valve core assembly; 4-stop valve; 5-safety oil external connector; 6-unpressurized return oil external connector; 7-vertical mounting bracket; 71-square base plate; 72-vertical support column. These components are all general standard parts or parts known to those skilled in the art. Their structure and principle can be learned by those skilled in the art through technical manuals or conventional experimental methods. The problem solved by the present invention is that the prior art relies solely on a single manual directional valve to control the safety oil circuit, lacks a local secondary safety confirmation structure, is prone to remote electrical misoperation, and has separate valve components and non-adjustable hydraulic trigger oil pressure, resulting in poor safety, adaptability, and maintenance convenience. This solution optimizes the turbine safety oil circuit control structure from multiple dimensions, including operational safety, operating condition adaptability, installation and maintenance, local control, and spatial layout. It eliminates the unit safety hazards caused by electrical malfunctions by forcibly confirming the oil circuit, expands the equipment's applicability by relying on the adjustable oil pressure structure, and simplifies on-site installation and maintenance by relying on highly integrated design. Overall reliability and practicality are comprehensively improved compared to traditional single-valve control solutions.

[0043] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered illustrative and non-limiting in all respects, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

[0044] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.

Claims

1. A novel adjustable mechanical reset hydraulic control valve, characterized in that: The system includes an integrated valve block assembly (1), a manual directional valve (2), an adjustable hydraulic directional valve (3), a shut-off valve (4), a safety oil external connector (5), a pressureless return oil external connector (6), and a vertical mounting bracket (7). The integrated valve block assembly (1) is rigidly fixed to the top of the vertical mounting bracket (7). The adjustable hydraulic directional valve (3) and the manual directional valve (2) are arranged side by side on the upper surface of the integrated valve block assembly (1). The shut-off valve (4) and the safety oil external connector (5) are installed on the left and right side walls of the integrated valve block assembly (1). The pressureless return oil external connector (6) is located on the left end of the front side wall of the integrated valve block assembly (1). The integrated valve block assembly (1) has interconnected internal flow channels cast inside to realize the connection of the oil ports of each valve. The front end of the manual reversing valve (2) is provided with an exposed manual operating handle (21). The manual reversing valve (2) has a P oil inlet, a T oil return port, an A working oil port and a B working oil port inside. The P oil inlet is connected to the internal flow channel of the safety oil external connector (5), and the T oil return port is connected to the internal flow channel of the pressureless oil return external connector (6). The adjustable hydraulic directional valve (3) has the adjustable spring valve core assembly (31) built in. The preload of the adjustable spring valve core assembly (31) can be externally adjusted to set the valve core switching trigger oil pressure. The adjustable hydraulic directional valve (3) has P port, T port, A port and B port inside. The control oil chamber of the adjustable hydraulic directional valve (3) is connected to the oil passage of the shut-off valve (4). The shut-off valve (4) is a manually operated hydraulic shut-off valve. The shut-off valve (4) has an oil inlet (P), an oil outlet (A), and a return oil outlet (B) inside. The oil inlet (P) is connected to the control oil chamber flow channel of the adjustable hydraulic directional valve (3).

2. The novel adjustable mechanical reset hydraulic control valve according to claim 1, characterized in that: The vertical mounting bracket (7) includes a square base plate (71) and a vertical support column (72); the square base plate (71) has four Φ13 mounting through holes at its four corners, and the lower end of the support column (72) is fixedly connected to the center of the square base plate (71).

3. The novel adjustable mechanical reset hydraulic control valve according to claim 1, characterized in that: The safety oil external connector (5) has a specification of Φ19 and is used to connect to the safety oil pipe of the turbine EH system; the pressureless return oil external connector (6) has a specification of Φ25 and is used to connect to the pressureless return oil pipeline of the system DV; both the safety oil external connector (5) and the pressureless return oil external connector (6) adopt a threaded sealing structure, and the safety oil external connector (5) and the pressureless return oil external connector (6) are independent of each other and have no interconnection oil passage.

4. The novel adjustable mechanical reset hydraulic control valve according to claim 1, characterized in that: The manual reversing valve (2) has two working positions: brake and de-brake. When the manual operating handle (21) is turned up to switch to the brake position, the safety oil enters the internal flow channel of the valve group through the P oil inlet. When the manual operating handle (21) is turned down to switch to the de-brake position, the safety oil is directly depressurized and returned to the external pressure-free return oil connector (6) through the T return oil port, so as to realize the local manual de-brake and depressurization of the steam turbine.

5. A novel adjustable mechanical reset hydraulic control valve according to claim 4, characterized in that: The adjustable hydraulic directional valve (3) and the shut-off valve (4) are connected in series through the internal flow channel of the integrated valve block assembly (1) to form a secondary safety confirmation and reset oil circuit. When only the remote electrical system performs the tripping operation, the safety oil circuit cannot establish pressure, and the turbine valves cannot operate. The shut-off valve (4) must be manually closed on-site to cut off the return oil pressure relief channel of the B return oil port of the shut-off valve (4). The safety oil pressure gradually increases. When the oil pressure exceeds the preset pressure value of the adjustable spring valve core assembly (31), the valve core inside the adjustable hydraulic directional valve (3) is reversed and reset, the oil circuit is fully connected, and the system can establish a stable safety oil circuit.

6. A novel adjustable mechanical reset hydraulic control valve according to claim 5, characterized in that: Once the system's safe oil pressure is fully established and the turbine is ready for operation, the on-site operator manually opens the shut-off valve (4), opens the B return port of the shut-off valve (4), releases the oil pressure inside the control oil chamber of the adjustable hydraulic directional valve (3), and releases the valve core oil pressure lock-up state. During normal operation of the unit, the oil circuit remains continuously open.

7. A novel adjustable mechanical reset hydraulic control valve according to claim 1, characterized in that: The adjustable spring valve core assembly (31) has an external pressure adjusting screw, a preload spring and a spring limit seat; the pressure adjusting screw is exposed on the outside of the adjustable hydraulic control directional valve (3) body. Rotating the pressure adjusting screw can change the compression of the preload spring, and can continuously adjust the trigger oil pressure required for the valve core switching of the adjustable hydraulic control directional valve (3) to adapt to the oil pressure parameter requirements of different unit EH system.

8. A novel adjustable mechanical reset hydraulic control valve according to claim 7, characterized in that: The integrated valve block assembly (1) is a one-piece hydraulic integrated block structure. The manual directional valve (2), adjustable hydraulic directional valve (3) and shut-off valve (4) are all directly stacked on the integrated valve block assembly (1). The oil circuit of each valve is connected by the prefabricated flow channel inside the valve block assembly (1), without the need for external transition oil pipes, thus reducing pipeline leakage points.

9. A novel adjustable mechanical reset hydraulic control valve according to claim 8, characterized in that: The entire valve assembly is connected to the turbine EH system pipeline only through two pipelines: the safety oil external connector (5) and the pressureless return oil external connector (6). The whole assembly is an independent set of components, which can be hoisted and disassembled as a whole. On-site installation, subsequent maintenance, and valve replacement are simple.

10. A novel adjustable mechanical reset hydraulic control valve according to claim 1, characterized in that: The valve group of the new type of adjustable mechanical reset hydraulic control valve is installed in series on the safety oil circuit of the turbine EH system. After the unit trips and depressurizes, the safety oil pressure cannot be restored by simply switching on the remote electrical device. It is necessary to force the on-site personnel to operate the shut-off valve (4) to complete the manual secondary confirmation, so as to avoid the turbine safety accident caused by the remote electrical device's mistaken switching on from the hydraulic circuit structure.

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