Hydraulic governing control system for feed pump turbine valve

Abstract

The application discloses a hydraulic speed regulation control system of a feed water pump turbine valve, which comprises a regulating valve control unit, the regulating valve control unit comprises a regulating valve hydraulic control block and a regulating valve oil actuator, a servo valve, a filter, a hydraulic control check valve, a differential pressure plug-in unloading valve, an upper plug-in stop valve, a lower plug-in stop valve, a quick closing electromagnetic valve, a pressure oil channel one, an oil discharge channel one and a safety oil channel are fixed in the regulating valve hydraulic control block; the safety oil channel is connected with the pressure oil channel one and the differential pressure plug-in unloading valve respectively; the quick closing electromagnetic valve is connected in parallel between the safety oil channel and the oil discharge channel one; the oil inlet of the servo valve is communicated with the filter, the control oil port is connected with the differential pressure plug-in unloading valve through the hydraulic control check valve, the differential pressure plug-in unloading valve is connected with the lower plug-in stop valve; the regulating valve oil actuator is connected with the upper plug-in stop valve and the lower plug-in stop valve respectively. The system can realize the replacement of the servo valve and the filter core on line, and solves the technical problem that the servo valve and the filter core cannot be replaced on line in the existing regulating valve speed regulation system.

Description

Technical Field

[0001] This invention relates to the field of feedwater pump turbine technology, specifically to a hydraulic speed control system for feedwater pump turbine valves. Background Technology

[0002] The feedwater pump turbine is one of the important pieces of equipment in the thermal cycle system of a thermal power plant. Its safety and reliability directly affect the safe operation of the entire unit. With the goal of saving investment costs, reducing maintenance costs, and improving the economic efficiency of the unit, more and more high-parameter, large-capacity steam turbines are equipped with only a single 100% full-capacity feedwater pump turbine. However, if the speed control system of the feedwater pump turbine regulating valve and the main steam valve malfunctions, it will be impossible to regulate the feedwater flow, which will seriously affect the safe operation of the unit and may even lead to unplanned unit shutdowns.

[0003] To eliminate potential hazards, improve the safety and reliability of the feedwater pump turbine, and ensure the safe and stable operation of the entire unit, different control schemes have been proposed for the regulating valve and the main steam valve, as follows:

[0004] Regarding the control of regulating valves, patent document CN213039551U discloses a hydraulic actuator system for a feedwater pump turbine regulating valve. This system includes a low-pressure regulating valve hydraulic actuator, a control module, a pressure oil channel, a return oil channel, a safety oil channel, and a safety isolation module. The safety isolation module includes a first unloading valve, a second unloading valve, a first hydraulically controlled check valve, a second hydraulically controlled check valve, and a servo valve. The pressure oil channel, the return oil channel, the lower and upper chambers of the cylinder of the low-pressure regulating valve hydraulic actuator, and the P, T, A, and B ports of the servo valve are connected. The second hydraulically controlled check valve is connected to the low-pressure regulating valve hydraulic actuator. The first unloading valve is connected to the pressure oil channel, and the second unloading valve is connected to the low-pressure regulating valve hydraulic actuator. Its drain port is connected to the return oil channel. The safety oil channel is connected to the first hydraulically controlled check valve and the second hydraulically controlled check valve, and also to the first and second unloading valves. This system, by placing the control module on the safety oil passage and using a servo valve to control the opening of the regulating valve, has the advantage of ensuring that the operation of the smaller unit does not affect the larger unit. However, because the servo valve is a very precise regulating component, it is easily affected by oil quality and can become stuck. Furthermore, this system cannot perform online replacement of the servo valve, which not only affects the control accuracy of the regulating valve but also impacts the safe operation of the unit. Additionally, the system adds a filter assembly to the pressure pipeline. While online replacement of the filter element can be achieved by opening the bypass shut-off valve and closing the upstream and downstream shut-off valves, this increases investment and maintenance costs and also prevents the simultaneous replacement of the servo valve and the filter element.

[0005] Existing technologies also propose adding a filter at the oil inlet of the servo valve to filter impurities, but the filter element is also prone to clogging, and existing technologies do not consider the online replacement of the filter element.

[0006] In addition, the accumulator of the above system is installed on the pressure oil header, which reduces its function of replenishing oil to the regulating valve. The main steam valve is generally fully open and does not participate in regulation. Therefore, it is unnecessary to install the accumulator on the pressure oil header. If the accumulator is installed on the pressure header, the capacity of the accumulator must be increased, which will increase the cost accordingly.

[0007] Regarding the control of the main steam valve, patent document CN115573960B discloses a high-pressure shutdown device for steam turbines with online monitoring and maintenance functions. This device features online monitoring and maintenance capabilities and improves the safety margin of the entire steam turbine unit while comprehensively enhancing reliability and response speed. However, this module consists of four solenoid valves in parallel and series configuration, three pressure switches, one pressure transmitter, four cartridge unloading valves, one oil circuit integration block, one pressure gauge, two throttle orifices, and multiple shut-off valves. The high-pressure shutdown device has a relatively complex structure and is only suitable for steam turbine units of 600,000 kW and above with a large number of valves. For feedwater pump turbines, its cost is high, and it can easily affect the reliability and stability of control, resulting in poor practicality.

[0008] Therefore, it is necessary to provide a new technology to solve the above-mentioned technical problems. Summary of the Invention

[0009] The purpose of this invention is to overcome the above-mentioned problems existing in the prior art and to provide a hydraulic speed control system for feedwater pump turbine valves. This system can realize the replacement of servo valves and filter elements online, avoiding downtime for replacing servo valves and filter elements. It solves the technical problem that existing regulating valve speed control systems cannot replace servo valves and filter elements online, thereby effectively improving the reliability and economy of the unit.

[0010] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0011] A hydraulic speed control system for a feedwater pump turbine valve includes a regulating valve control unit. The regulating valve control unit comprises a regulating valve hydraulic control block and a regulating valve hydraulic actuator. The regulating valve hydraulic control block is fixedly equipped with a servo valve, a filter, a hydraulically controlled check valve, a differential pressure cartridge unloading valve, an upper cartridge shut-off valve, a lower cartridge shut-off valve, a quick-closing solenoid valve, a pressure oil passage, a discharge oil passage, and a safety oil passage. The pressure oil passage is connected to the inlet ports of the filter, the upper cartridge shut-off valve, and the differential pressure cartridge unloading valve, respectively. One end of the safety oil passage is connected to the pressure oil passage through a safety oil throttling orifice, and the other end is connected to the differential pressure cartridge unloading valve. The control port of the pressure-type cartridge unloading valve is connected; the quick-closing solenoid valves are redundantly connected in parallel between the safety oil passage and the first drain channel to control whether the safety oil passage and the first drain channel are connected; the inlet of the servo valve is connected to the filter, the control port of the servo valve is connected to the left port of the differential pressure cartridge unloading valve through the hydraulic check valve, the drain port of the servo valve is connected to the first drain channel, the pilot port of the hydraulic check valve is connected to the safety oil passage, and the right port of the differential pressure cartridge unloading valve is connected to the lower cartridge shut-off valve; the rod chamber and rodless chamber of the regulating valve hydraulic actuator are connected to the upper cartridge shut-off valve and the lower cartridge shut-off valve, respectively.

[0012] The differential pressure cartridge unloading valve and the hydraulic control check valve are provided with a rodless chamber pressure measuring point A, and the upper cartridge shut-off valve and the pressure oil passage are provided with a rod chamber pressure measuring point B.

[0013] The oil discharge channel is equipped with a one-way valve A and an oil discharge pressure measuring point. The oil discharge pressure measuring point is close to the quick-closing solenoid valve, and the oil discharge port of the servo valve is connected between the one-way valve A and the oil discharge pressure measuring point.

[0014] The safety oil passage is equipped with a safety oil pressure measuring point.

[0015] The hydraulic speed control system further includes a high-pressure energy storage unit, which includes an accumulator bladder, a pressure oil shut-off valve, a one-way valve B, and an oil discharge pipe. The oil inlet of the one-way valve B is connected to the main pressure oil port, and the oil outlet of the one-way valve B is split into two outputs. One output is connected to the pressure oil passage through a ball valve A, and the other output is connected to the accumulator bladder through the pressure oil shut-off valve. The oil discharge pipe is connected between the pressure oil shut-off valve and the accumulator bladder.

[0016] The oil drain fitting includes an oil drain pipe, a pressure gauge, a pressure gauge shut-off valve, and an oil drain shut-off valve. One end of the oil drain pipe is connected between the pressure oil shut-off valve and the accumulator bladder, and the other end is connected to the return port through the oil drain shut-off valve. The pressure gauge is connected to the oil drain pipe through the pressure gauge shut-off valve.

[0017] The hydraulic speed control system further includes a main steam valve control unit, which comprises a main steam valve hydraulic control block and a main steam valve hydraulic actuator. The main steam valve hydraulic control block is fixedly equipped with a test solenoid valve, a shut-off solenoid valve, a test throttle orifice, a second drain channel, and a second pressure channel. One end of the second pressure channel is connected to the main pressure port via a ball valve B, and the other end is connected to the rod-side chamber of the main steam valve hydraulic actuator. One end of the second drain channel is connected to the return port, and the other end is connected to the rodless chamber of the main steam valve hydraulic actuator. The shut-off solenoid valves are redundantly connected in parallel between the second drain channel and the second pressure channel to control whether the two channels are connected. The test solenoid valve and the test throttle orifice are sequentially connected to the second pressure channel. The drain port of the test solenoid valve is connected to the second drain channel, and the test throttle orifice is located between the test solenoid valve and the shut-off solenoid valve.

[0018] The second oil discharge channel is equipped with a rodless chamber pressure measuring point C, and the second pressure oil channel is equipped with a rod chamber pressure measuring point D.

[0019] The second oil drain channel is equipped with a one-way valve C, and the oil drain port of the test solenoid valve is connected to the oil inlet end of the one-way valve C.

[0020] The advantages of using this invention are:

[0021] 1. This invention employs a hydraulic control block and a hydraulic actuator with a specific structure for the regulating valve, enabling online replacement of the servo valve and filter element. This avoids downtime for replacing the servo valve and filter element, solving the technical problem of existing regulating valve speed control systems that cannot replace the servo valve and filter element online. This not only effectively improves the reliability and economy of the unit, but also brings indirect economic benefits to the power plant.

[0022] 2. This invention employs a specific high-pressure energy storage unit, which is installed on the branch pipe of the pressure oil pipeline of the hydraulic control block of the regulating valve. It can realize the function of rapid oil replenishment when the regulating valve is opened quickly, and prevent the system from vibrating due to the pressure pipeline when the regulating valve is rapidly replenished. Furthermore, this specific high-pressure energy storage unit only replenishes oil for the regulating valve's hydraulic actuator, which is beneficial to reducing the size of the energy storage device and lowering costs.

[0023] 3. This invention employs a specific structure for the main steam valve hydraulic control block and main steam valve oil actuator. It controls the flow of safety oil by configuring two redundant two-position two-way shut-off solenoid valves, resulting in a simple structure and reduced investment costs for the owner. Furthermore, optimization of the solenoid valve control logic enables rapid closure of the main steam valve and resolves non-stoppages caused by malfunctions of the fast-closing solenoid valve, thus improving the unit's economic efficiency.

[0024] 4. This invention can monitor the pressure at key points in the system in real time through various pressure measuring points, which helps to ensure the safe, stable and reliable operation of the system.

[0025] 5. The present invention is equipped with a check valve in both the hydraulic control block of the regulating valve and the hydraulic control block of the main steam valve. The check valve can prevent oil from other valves from flowing back into the corresponding hydraulic actuator, which helps to avoid the unit from being shut down due to a drop in system pressure.

[0026] 6. This invention eliminates the need for a separate high-pressure tripping device for the safety oil. The independent high-pressure tripping device must be installed lower than the safety oil port of all hydraulic actuators, and its drain port must be the return port of the high-pressure oil station. Otherwise, when the unit trips, the installation position of the high-pressure tripping module can cause poor safety oil drainage, resulting in the unit's fast shutdown time failing to meet national standards, and potentially even causing the unit to run away. This invention uses two redundant two-position two-way tripping solenoid valves on the main steam valve and regulating valve hydraulic control blocks to control the on / off of the safety oil, avoiding the aforementioned problems caused by improper installation of the independent high-pressure tripping device. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of the hydraulic control principle of the regulating valve control unit in Example 1;

[0028] Figure 2 This is a schematic diagram of the hydraulic control principle for Example 2;

[0029] Figure 3 This is a schematic diagram of the hydraulic control principle of the high-pressure energy storage unit in Example 2;

[0030] Figure 4 This is a schematic diagram of the hydraulic control principle for Example 3;

[0031] Figure 5 This is a schematic diagram of the hydraulic control principle of the main steam valve control unit in Example 3.

[0032] The following are labeled in the diagram: 1. Hydraulic control block for regulating valve; 2. Hydraulic actuator for regulating valve; 3. Servo valve; 4. Filter; 5. Hydraulic check valve; 6. Differential pressure cartridge unloading valve; 7. Upper cartridge shut-off valve; 8. Lower cartridge shut-off valve; 9. Quick-closing solenoid valve; 10. Pressure oil passage one; 11. Discharge oil passage one; 12. Safety oil passage; 13. Rodless chamber pressure measuring point A; 14. Rod chamber pressure measuring point B; 15. Check valve A; 16. Discharge oil pressure measuring point; 17. Safety oil pressure measuring point; 18. Safety oil throttle orifice; 19. Ball valve A; 20. High-pressure energy storage unit; 21. Accumulator bladder. 22. Pressure oil shut-off valve; 23. Check valve B; 24. Oil drain pipe; 25. Pressure gauge; 26. Pressure gauge shut-off valve; 27. Oil drain shut-off valve; 28. Main steam valve hydraulic control block; 29. ​​Main steam valve hydraulic actuator; 30. Test solenoid valve; 31. Shut-off solenoid valve; 32. Test throttle orifice; 33. Oil drain channel two; 34. Pressure oil channel two; 35. Rodless chamber pressure measuring point C; 36. Rod chamber pressure measuring point D; 37. Check valve C; 38. Ball valve B; 39. Valve fully closed position limit switch; 40. Valve test position limit switch; 41. Valve fully open position limit switch. Detailed Implementation

[0033] Example 1

[0034] like Figure 1As shown, this embodiment provides a hydraulic speed control system for a feedwater pump turbine valve. The system includes a regulating valve control unit for controlling the regulating valve. The regulating valve control unit includes a regulating valve hydraulic control block 1 and a regulating valve hydraulic actuator 2. The regulating valve hydraulic control block 1 is fixedly equipped with a servo valve 3, a filter 4, a hydraulically controlled check valve 5, a differential pressure cartridge unloading valve 6, an upper cartridge shut-off valve 7, a lower cartridge shut-off valve 8, a quick-closing solenoid valve 9, a pressure oil passage 10, an oil discharge passage 11, and a safety oil passage 12. The pressure oil passage 10 has a main inlet and multiple branches. The main inlet is connected to the main pressure port through an external ball valve A19. The pressure oil passage 10 is connected to the inlets of the filter 4, the upper cartridge shut-off valve 7, and the differential pressure cartridge unloading valve 6 through multiple branches. One end of the safety oil passage 12 is connected to the pressure oil passage 10 through the safety oil throttle orifice 18, and the other end is connected to the control port of the differential pressure cartridge unloading valve 6. To ensure economy and redundancy, the number of quick-closing solenoid valves 9 is preferably two. These two quick-closing solenoid valves 9 are redundantly connected in parallel between the safety oil passage 12 and the drain channel 11 to control whether the safety oil passage 12 and the drain channel 11 are connected. The inlet of the servo valve 3 is connected to the filter 4. The control port of the servo valve 3 is connected to the left port of the differential pressure cartridge unloading valve 6 through the hydraulic check valve 5. The outlet of the servo valve 3 is connected to the drain channel 11. The pilot port of the hydraulic check valve 5 is connected to the safety oil passage 12. The right port of the differential pressure cartridge unloading valve 6 is connected to the lower cartridge shut-off valve 8. The rod-side and rodless-side chambers of the regulating valve hydraulic actuator 2 are connected to the upper cartridge shut-off valve 7 and the lower cartridge shut-off valve 8, respectively.

[0035] According to a preferred embodiment of this example, such as Figure 1 As shown, a rodless chamber pressure measuring point A13 is provided between the differential pressure cartridge unloading valve 6 and the hydraulic control check valve 5; a rod chamber pressure measuring point B14 is provided between the upper cartridge shut-off valve 7 and the pressure oil passage 10; a safety oil pressure measuring point 17 is provided on the safety oil passage 12; a check valve A15 and a drain pressure measuring point 16 are provided on the drain passage 11, and the drain pressure measuring point 16 is close to the quick-closing solenoid valve 9; the drain port of the servo valve 3 is connected between the check valve A15 and the drain pressure measuring point 16.

[0036] The hydraulic control principle of this embodiment is as follows:

[0037] Pressurized oil enters pressure oil passage 10 through ball valve A19. The pressurized oil then passes through safety oil throttle orifice 18 to form safety oil. Two redundant quick-closing solenoid valves 9 are installed between safety oil passage 12 and drain passage 11 to control whether safety oil passage 12 is connected to drain passage 11. Safety oil pressure measuring point 17 is located on safety oil passage 12 to monitor the safety oil pressure. An internal filter element 4 is located at the front end of servo valve 3 to filter impurities in the oil and prevent servo valve 3 from jamming. Servo valve 3 adopts a redundant coil double-nozzle baffle structure. A hydraulic check valve 5 is located on the pressure passage after pressurized oil enters servo valve 3. A differential pressure cartridge unloading valve 6 is located on the pressure passage where pressurized oil enters the rodless chamber of regulating valve hydraulic actuator 2. Rodless chamber pressure measuring point A13 and rod chamber pressure measuring point B14 are located on the pressure passages of the rodless and rod chambers of regulating valve hydraulic actuator 2, respectively, to monitor the pressure in the rodless and rod chambers of regulating valve hydraulic actuator 2. The lower cartridge shut-off valve is used to control the pressure oil entering and exiting the rodless chamber of the regulating valve hydrator 2, and the upper cartridge shut-off valve is used to control the pressure oil entering and exiting the rod chamber of the regulating valve hydrator 2. The oil discharge pressure measuring point 16 set on the oil discharge channel 11 is used to monitor the oil discharge pressure. The one-way valve A15 set on the oil discharge channel 11 is used to prevent oil from other valves from flowing back into the chamber of the regulating valve hydrator 2, causing a drop in system pressure and resulting in unit shutdown.

[0038] The usage method or workflow of this embodiment is as follows:

[0039] Before the unit is switched on, the quick-closing solenoid valve 9 is de-energized, the safety oil passage 12 and the drain oil passage 11 are connected, the safety oil is not established, the hydraulic control check valve 5 can only be opened in one direction, the pressure oil passes through the ball valve A19, the lower chamber of the differential pressure cartridge unloading valve 6 and the lower cartridge shut-off valve 8 and enters the rodless chamber of the regulating valve hydraulic actuator 2. At the same time, the pressure oil passes through the upper cartridge shut-off valve 7 and enters the rod chamber of the regulating valve hydraulic actuator 2. When the upper and lower chambers of the regulating valve hydraulic actuator 2 have different areas, the force in the rodless chamber is greater than the force in the rod chamber, and the valve is in the closed state. At this time, the spring-assisted valve on the regulating valve actuator closes.

[0040] After the unit is successfully engaged, the two redundant fast-closing solenoid valves 9 are energized. The pressurized oil passes through ball valve A19 and safety oil throttle orifice 18 to form safety oil. The safety oil enters the hydraulic control check valve 5 through the pilot port. The pilot oil circuit of the hydraulic control check valve 5 is opened, and the hydraulic control check valve 5 is bidirectionally oriented. The safety oil enters the upper chamber of the differential pressure cartridge unloading valve 6, controlling the valve core to move downward and close the differential pressure cartridge unloading valve 6. At this time, the pressurized oil is cut off and cannot enter the rodless chamber of the regulating valve hydraulic motor 2. The rodless chamber of the regulating valve hydraulic motor 2 is connected to the hydraulic control check valve 5 and servo valve 3 through the left and right oil ports of the differential pressure cartridge unloading valve 6. At this time, oil inlet or outlet can be achieved through servo commands.

[0041] Based on the above, when servo valve 3 receives an opening command, servo valve 3 connects control port B with drain port T, releasing the oil pressure in the rodless chamber of regulating valve hydrator 2. Under the action of the oil pressure in the rod chamber of regulating valve hydrator 2, the valve gradually opens until the valve opening reaches the given commanded opening position. Servo valve 3 automatically centers and holds the position. When servo valve 3 receives a closing command, servo valve 3 connects inlet port P with control port B. Under the force difference between the upper and lower chambers, regulating valve hydrator 2 gradually closes the valve. When the given commanded position is reached, servo valve 3 automatically centers and holds the position.

[0042] Based on the above, when the unit receives a trip signal, the two redundant fast-closing solenoid valves 9 of the regulating valve hydraulic actuator 2 are simultaneously de-energized, the safety oil passage 12 is connected to the oil drain passage 11, the safety oil in the upper chamber of the differential pressure cartridge unloading valve 6 is depressurized through the oil drain passage 11, the valve core of the differential pressure cartridge unloading valve 6 opens, and the pressure oil enters the rodless chamber of the regulating valve hydraulic actuator 2 through the differential pressure cartridge unloading valve 6. At this time, the hydraulic control check valve 5 can only be unidirectionally opened. Under the action of the force difference between the upper and lower chambers and the cooperation of the spring, the regulating valve hydraulic actuator 2 realizes the rapid closure of the regulating valve.

[0043] Furthermore, during normal unit operation, when a differential pressure alarm occurs on filter element 4, the filter element can be replaced online. The replacement procedure is as follows:

[0044] First, the valve position of the regulating valve is relatively stable, and the servo valve 3 is in the neutral position. First, close the lower cartridge stop valve 8, then close the upper cartridge stop valve 7 to achieve the valve position holding function. Then, close the ball valve A19 on the pressure oil line to cut off the continuous supply of pressure oil. This causes either of the two redundant fast-closing solenoid valves 9 to be de-energized for 2 seconds and then re-energized. The purpose is to release the internal pressure of the regulating valve hydraulic control block 1. Then, remove the filter 4 that has triggered an alarm signal and replace it with a new filter element. After the filter element replacement is completed, open the ball valve A19 to allow pressure oil to enter. The pressure of the safety oil is restored through the safety oil throttle orifice 18. The pressure of the differential pressure cartridge unloading valve 6 is judged by the pressure measuring point 17 on the safety oil line to determine whether the differential pressure cartridge unloading valve 6 is successfully closed. With the differential pressure cartridge unloading valve 6 closed, open the upper cartridge stop valve 7 and the lower cartridge stop valve 8 at the same time to restore the unit to normal operation.

[0045] Furthermore, during normal unit operation, if servo valve 325 malfunctions, servo valve 3 can be replaced online. The replacement procedure is as follows:

[0046] If servo valve 3 malfunctions during normal unit operation, the output of servo card commands will be disabled first.

[0047] First, close the lower cartridge stop valve 8, then close the upper cartridge stop valve 7 to achieve the valve position holding function. Then close the ball valve A19 on the pressure oil line to cut off the continuous supply of pressure oil. This causes either of the two redundant fast-closing solenoid valves 9 to be de-energized for 2 seconds and then re-energized. The purpose is to release the internal pressure of the regulating valve hydraulic control block 1.

[0048] Then, disassemble the malfunctioning servo valve 3 and replace it with a new servo valve 3. After the replacement of servo valve 3 is completed, open ball valve A19 to allow pressure oil to enter. Restore the pressure of safety oil through safety oil throttle orifice 18. Determine whether the differential pressure cartridge unloading valve 6 is successfully closed by using safety oil pressure measuring point 17. With the differential pressure cartridge unloading valve 6 closed, simultaneously open upper cartridge stop valve 7 and lower cartridge stop valve 8, and reset the servo card to fully restore the unit to normal operation.

[0049] This embodiment can also detect whether the safety oil has been successfully established. Specifically, it can determine whether the safety oil throttle orifice 18 is blocked or whether there is a problem with the quick-closing solenoid valve 9 by checking the pressure of the safety oil pressure measuring point 17 on the safety oil passage 12 and the pressure of the drain oil pressure measuring point 16 on the drain oil passage 11.

[0050] Example 2

[0051] like Figure 2 , 3 As shown, this embodiment adds a high-pressure energy storage unit 20 to the embodiment 1. The high-pressure energy storage unit 20 includes an accumulator bladder 21, a pressure oil shut-off valve 22, a one-way valve B23, and an oil discharge pipe. The oil inlet of the one-way valve B23 is connected to the main pressure oil port. The oil outlet of the one-way valve B23 is divided into two outputs. One output is connected to the pressure oil passage 10 through a ball valve A19, and the other output is connected to the accumulator bladder 21 through the pressure oil shut-off valve 22. The oil discharge pipe is connected between the pressure oil shut-off valve 22 and the accumulator bladder 21.

[0052] Furthermore, the oil drain fittings include an oil drain pipe 24, a pressure gauge 25, a pressure gauge shut-off valve 26, and an oil drain shut-off valve 27. One end of the oil drain pipe 24 is connected between the pressure oil shut-off valve 22 and the accumulator bladder 21, and the other end is connected to the return port through the oil drain shut-off valve 27. The pressure gauge 25 is connected to the oil drain pipe 24 through the pressure gauge shut-off valve 26. The pressure gauge 25 is used to check the oil pressure in the pressure channel. The pressure gauge shut-off valve 26 is installed before the oil inlet of the pressure gauge 25 to cut off the pressure oil when replacing the pressure gauge 25.

[0053] During normal operation of the unit, the pressure gauge shut-off valve 26 and the pressure oil shut-off valve 22 are open, and the oil drain shut-off valve 27 is closed. The system pressure oil passes through the check valve B23, with part of it entering the accumulator bladder 21 to store energy and part of it entering the regulating valve hydraulic actuator 2 through the ball valve A19. During normal operation of the unit, the accumulator bladder 21 can absorb hydraulic shocks and reduce pulsation. When the regulating valve needs to be opened quickly, the accumulator bladder 21 can act as an auxiliary power source to replenish oil to the regulating valve hydraulic actuator 2, which can prevent the phenomenon of pipeline vibration and regulating valve vibration caused by excessive oil replenishment.

[0054] This embodiment also enables online replacement of the accumulator bladder 21. If the accumulator bladder 21 is damaged, first close the pressure oil shut-off valve 22 to avoid affecting the normal operation of the unit. Then open the drain oil shut-off valve 27 to allow the pressure oil in the accumulator bladder 21 to flow through the drain oil pipe 24 to the return oil port. After the oil in the accumulator bladder 21 has completely returned to the oil tank, close the drain oil shut-off valve 27 and replace it with a new accumulator bladder 21. After the bladder replacement is completed, open the pressure oil shut-off valve 22 to allow the pressure oil to enter the accumulator bladder 21 to store energy and restore the function of the high-voltage accumulator.

[0055] Example 3

[0056] This embodiment adds a main steam valve control unit to the existing embodiments 1 and 2. Typically, a feedwater pump turbine includes two main steam valves, so two sets of main steam valve control units are added. These two sets of main steam valve control units can share the return oil port and the main pressure oil port with the regulating valve control unit, and are used to control the opening degree of the two main steam valves respectively.

[0057] like Figure 4 , 5 As shown, the main steam valve control unit includes a main steam valve hydraulic control block 28 and a main steam valve hydraulic actuator 29. The main steam valve hydraulic control block 28 is fixedly equipped with a test solenoid valve 30, a shut-off solenoid valve 31, a test throttle orifice 32, a second oil discharge channel 33, and a second pressure oil channel 34. One end of the second pressure oil channel 34 is connected to the main pressure oil port via a ball valve B38, and the other end is connected to the rod-side chamber of the main steam valve hydraulic actuator 29. One end of the second oil discharge channel 33 is connected to the return oil port, and the other end is connected to the rodless chamber of the main steam valve hydraulic actuator 29. There can be two shut-off solenoid valves 31, which are redundantly connected in parallel between the second oil discharge channel 33 and the second pressure oil channel 34, used to control whether the second oil discharge channel 33 and the second pressure oil channel 34 are connected. The test solenoid valve 30 and the test throttle orifice 32 are connected in sequence to the second pressure oil passage 34. The oil outlet of the test solenoid valve 30 is connected to the second oil outlet passage 33. The test throttle orifice 32 is located between the test solenoid valve 30 and the shut-off solenoid valve 31.

[0058] According to a preferred embodiment of this example, such as Figure 4 ,5 As shown, pressure measuring point D36 of rod chamber is provided on pressure oil passage 2 34, and pressure measuring point C35 of rodless chamber and check valve C37 are provided on oil discharge passage 2 33. Pressure measuring point C35 of rodless chamber is located between check valve C37 and rodless chamber of main steam valve hydrant 29. Oil discharge port of test solenoid valve 30 is connected to oil inlet end of check valve C37.

[0059] The hydraulic control principle of this embodiment is as follows:

[0060] Pressurized oil enters the main steam valve hydraulic control block 28 via ball valve B38. Test solenoid valve 30 is installed on pressure oil passage 34. Test throttle orifice 32 is installed at control port A of test solenoid valve 30. The inlet and outlet speeds are controlled by adjusting the orifice diameter of test throttle orifice 32. Two redundant shut-off solenoid valves 31 are used to control whether pressurized oil is connected to outlet passage 33. Rodless chamber pressure measuring point C35 and rod chamber pressure measuring point D36 are used to monitor the oil pressure in the rodless and rod chambers of the main steam valve hydraulic actuator 29. Check valve C37 is used to prevent backflow of oil from other valves into the chamber of the main steam valve hydraulic actuator 29. The main steam valve is equipped with two valve fully closed limit switches 39 to monitor the fully closed signal; one valve fully open limit switch to monitor the fully open signal; and a valve test position limit switch 40 for valve movement testing to check for jamming in the main steam valve.

[0061] The usage method or workflow of this embodiment is as follows:

[0062] When the unit is successfully engaged, the test solenoid valve 30 is energized, and the pressure oil is cut off by the test solenoid valve 30. The two shut-off solenoid valves 31 are energized, and the pressure oil passage 2 34 and the oil discharge passage 2 33 are not connected. At this time, the conditions for valve opening are met, the main steam valve is in the fully closed state, and the two valve fully closed position limit switches 39 send signals. When the test solenoid valve 30 is de-energized, the pressure oil passes through the test solenoid valve 30 (P port → A port), and enters the rod chamber (working chamber) of the main steam valve hydraulic actuator 29 through the test throttle orifice 32. Under the action of the pressure oil, the valve gradually opens by overcoming resistance until the valve is fully open. At this time, the valve fully open position limit switch 41 sends signals.

[0063] Based on the above, a valve operation test is conducted. The test solenoid valve 30 is energized (solenoid valve A port and T port are connected). At this time, the pressure oil inlet is cut off by the test solenoid valve 30. Under the action of the spring, the oil in the rod chamber of the main steam valve hydrant 29 is connected to the second drain channel 33 through the test solenoid valve 30. The oil in the rod chamber of the main steam valve hydrant 29 enters the oil tank through the test throttle orifice 32 and the second drain channel 33, and the valve gradually closes. When the valve test position limit switch 40 signals, the test solenoid valve 30 is automatically de-energized, and the pressure oil enters the rod chamber of the main steam valve hydrant 29 through the test solenoid valve 30 A port. The valve gradually returns to fully open, and at this time, the fully open position limit switch signals.

[0064] Based on the above, when the two redundant shut-off solenoid valves 31 receive the unit trip signal, the two shut-off solenoid valves 31 are simultaneously de-energized, the pressure oil passage 2 34 and the oil discharge passage 2 33 are connected, and the valves are quickly closed under the action of the spring.

[0065] The above description is merely a specific embodiment of the present invention. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All features or steps in all methods or processes disclosed may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A hydraulic speed control system for a feedwater pump turbine valve, characterized in that: The system includes a regulating valve control unit, which comprises a regulating valve hydraulic control block (1) and a regulating valve hydraulic actuator (2). The regulating valve hydraulic control block (1) is fixedly equipped with a servo valve (3), a filter (4), a hydraulic check valve (5), a differential pressure cartridge unloading valve (6), an upper cartridge shut-off valve (7), a lower cartridge shut-off valve (8), a quick-closing solenoid valve (9), a pressure oil passage (10), an oil discharge passage (11), and a safety oil passage (12). The pressure oil passage (10) is connected to the oil inlets of the filter (4), the upper cartridge shut-off valve (7), and the differential pressure cartridge unloading valve (6), respectively. One end of the safety oil passage (12) is connected to the pressure oil passage (10) through a safety oil throttle orifice (18), and the other end is connected to the differential pressure cartridge unloading valve (6). The control port of the valve is connected; the quick-closing solenoid valve (9) is redundantly connected in parallel between the safety oil passage (12) and the first drain channel (11) to control whether the safety oil passage (12) and the first drain channel (11) are connected; the inlet of the servo valve (3) is connected to the filter (4), the control port of the servo valve (3) is connected to the left port of the differential pressure cartridge unloading valve (6) through the hydraulic check valve (5), the drain port of the servo valve (3) is connected to the first drain channel (11), the pilot port of the hydraulic check valve (5) is connected to the safety oil passage (12), and the right port of the differential pressure cartridge unloading valve (6) is connected to the lower cartridge stop valve (8); the rod chamber and rodless chamber of the regulating valve hydraulic motor (2) are connected to the upper cartridge stop valve (7) and the lower cartridge stop valve (8) respectively. It also includes a main steam valve control unit, which includes a main steam valve hydraulic control block (28) and a main steam valve hydraulic actuator (29). The main steam valve hydraulic control block (28) is fixedly equipped with a test solenoid valve (30), a shut-off solenoid valve (31), a test throttle orifice (32), an oil discharge channel two (33), and a pressure oil passage two (34). One end of the pressure oil passage two (34) is connected to the main pressure oil port through a ball valve B (38), and the other end is connected to the rod chamber of the main steam valve hydraulic actuator (29). One end of the oil discharge channel two (33) is used to connect to the return oil port. One end is connected to the rodless chamber of the main steam valve hydrator (29); the shut-off solenoid valve (31) is redundantly connected in parallel between the second drain channel (33) and the second pressure oil channel (34) to control whether the second drain channel (33) and the second pressure oil channel (34) are connected; the test solenoid valve (30) and the test throttle orifice (32) are connected in sequence on the second pressure oil channel (34), the drain port of the test solenoid valve (30) is connected to the second drain channel (33), and the test throttle orifice (32) is located between the test solenoid valve (30) and the shut-off solenoid valve (31).

2. The hydraulic speed control system for a feedwater pump turbine valve according to claim 1, characterized in that: The differential pressure cartridge unloading valve (6) is provided with rodless chamber pressure measuring point A (13) between the hydraulic control check valve (5) and rod chamber pressure measuring point B (14) between the upper cartridge shut-off valve (7) and the pressure oil passage (10).

3. The hydraulic speed control system for a feedwater pump turbine valve according to claim 1, characterized in that: The oil drain channel 1 (11) is equipped with a one-way valve A (15) and an oil drain pressure measuring point (16). The oil drain pressure measuring point (16) is close to the fast-closing solenoid valve (9). The oil drain port of the servo valve (3) is connected between the one-way valve A (15) and the oil drain pressure measuring point (16).

4. The hydraulic speed control system for a feedwater pump turbine valve according to claim 1, characterized in that: The safety oil passage (12) is equipped with a safety oil pressure measuring point (17).

5. The hydraulic speed control system for a feedwater pump turbine valve according to claim 1, characterized in that: It also includes a high-pressure energy storage unit (20), which includes an accumulator bladder (21), a pressure oil shut-off valve (22), a one-way valve B (23), and an oil drain pipe (24). The oil inlet of the one-way valve B (23) is connected to the main pressure oil port. The oil outlet of the one-way valve B (23) is divided into two outputs. One output is connected to the pressure oil passage 1 (10) through a ball valve A (19), and the other output is connected to the accumulator bladder (21) through the pressure oil shut-off valve (22). The oil drain pipe (24) is connected between the pressure oil shut-off valve (22) and the accumulator bladder (21).

6. A hydraulic speed control system for a feedwater pump turbine valve according to claim 5, characterized in that: The oil drain pipe (24) includes an oil drain pipe (24), a pressure gauge (25), a pressure gauge shut-off valve (26), and an oil drain shut-off valve (27). One end of the oil drain pipe (24) is connected between the pressure oil shut-off valve (22) and the accumulator bladder (21), and the other end is connected to the return port through the oil drain shut-off valve (27). The pressure gauge (25) is connected to the oil drain pipe (24) through the pressure gauge shut-off valve (26).

7. The hydraulic speed control system for a feedwater pump turbine valve according to claim 1, characterized in that: The second oil discharge channel (33) is provided with a rodless chamber pressure measuring point C (35), and the second pressure oil channel (34) is provided with a rod chamber pressure measuring point D (36).

8. A hydraulic speed control system for a feedwater pump turbine valve according to claim 1, characterized in that: The second oil drain channel (33) is equipped with a one-way valve C (37), and the oil drain port of the test solenoid valve (30) is connected to the oil inlet end of the one-way valve C (37).

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