Hydraulic speed regulation control system of feed pump turbine valve

Abstract

The invention discloses a hydraulic speed regulation control system of a feed pump turbine valve, which comprises a regulating valve control unit, and the regulating valve control unit comprises a regulating valve hydraulic control block and a regulating valve hydraulic servo-motor. A servo valve, a filter, a hydraulic control one-way valve, a differential pressure type plug-in loading and unloading valve, an upper plug-in stop valve, a lower plug-in stop valve, a quick-closing electromagnetic valve, a first pressure oil channel, a first oil discharge channel and a safety oil channel are fixed in the adjusting valve hydraulic control block. The safety oil duct is connected with the first pressure oil duct and the differential pressure type plug-in loading and unloading valve. The quick-closing electromagnetic valve is connected in parallel between the safe oil duct and the oil discharge channel I; an oil inlet of the servo valve is communicated with the filter, a control oil port is connected with the differential pressure type plug-in loading valve through the hydraulic control one-way valve, and the differential pressure type plug-in loading valve is connected with the lower plug-in stop valve; and the regulating valve hydraulic servo-motor is respectively connected with the upper cartridge stop valve and the lower cartridge stop valve. According to the system, the servo valve and the filter element can be replaced on line, and the technical problem that the servo valve and the filter element cannot be replaced on line in an existing regulating valve speed regulating system is solved.

Description

Technical Field

[0001] The invention relates to the technical field of feedwater pump steam turbines, and in particular to a hydraulic speed regulation control system for a feedwater pump steam turbine valve. Background Art

[0002] The feedwater pump turbine is one of the important equipment in the thermal cycle system of a thermal power plant. Its safety and reliability directly affects the safe operation of the entire unit. With the savings in investment costs and maintenance costs, as well as the improvement of the economy of the unit, more and more high-parameter and large-capacity steam turbines are only equipped with a single 100% full-capacity feedwater pump turbine. However, if only a single feedwater pump turbine is configured, if the speed control system that controls the feedwater pump turbine regulating valve and the main steam valve fails, the feedwater flow rate will not be able to be adjusted, which will seriously affect the operating safety of the unit and even cause the unit to shut down.

[0003] In order to eliminate hidden dangers, 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: Regarding the control of the regulating valve, the patent document with the announcement number CN213039551U discloses a feedwater pump turbine regulating valve oil motor system, which includes a low-pressure regulating valve oil motor, a control module, a pressure oil channel, an oil return 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 one-way valve, a second hydraulically controlled one-way valve, and a servo valve. The pressure oil channel, the oil return channel, the lower chamber and upper chamber of the oil cylinder of the low-pressure regulating valve oil motor and the P port, T port, A port, and B port of the servo valve are connected, and the second hydraulically controlled one-way valve is connected to the low-pressure regulating valve oil motor; the first unloading valve is connected to the pressure oil channel, and the second unloading valve is connected to the low-pressure regulating valve oil motor, and its oil discharge port is connected to the oil return channel; the safety oil channel is connected to the first hydraulically controlled one-way valve and the second hydraulically controlled one-way valve, and the safety oil channel is connected to the first unloading valve and the second unloading valve. The system sets the control module on the safety oil channel and uses the servo valve to control the opening of the regulating valve, which has the advantage that the working state of the small machine will not affect the large machine. However, since the servo valve is a very precise regulating part, it is easily affected by the oil quality and stuck, and the system cannot realize the online replacement of the servo valve, which not only affects the control accuracy of the regulating valve, but also affects the safe operation of the unit. In addition, the system adds a filter assembly to the pressure pipeline, which can realize the online replacement of the filter element by opening the bypass stop valve and closing the upstream and downstream stop valves of the filter element. On the one hand, it increases the investment cost and maintenance cost, and on the other hand, it cannot realize the replacement of the servo valve and the filter element at the same time.

[0004] The prior art also proposes a structure in which a filter is added to the oil inlet end of the servo valve to filter impurities, but the filter element is also easily clogged, and the prior art also does not consider the online replacement of the filter element.

[0005] In addition, the accumulator of the above system is installed on the pressure oil main pipe, which reduces the effect of replenishing oil for the regulating valve, and the main steam valve is generally fully open and does not participate in the regulation. Therefore, there is no need to install the accumulator on the pressure oil main pipe. If the accumulator is installed on the pressure main pipe, the capacity of the accumulator must be increased, which will lead to a corresponding increase in cost.

[0006] Regarding the control of the main steam valve, the patent document with the announcement number CN115573960B discloses a steam turbine high-pressure shutoff device with online monitoring and maintenance functions, which has online monitoring and maintenance functions, and improves the safety margin of the entire steam turbine unit on the basis of comprehensively improving reliability and response speed. However, the module consists of four solenoid valves in parallel mode, three pressure switches, a pressure transmitter, four plug-in unloading valves, an oil circuit integrated block, a pressure gauge, two throttle holes and multiple stop valves. However, the structure of the high-pressure shutoff device is relatively complex, and it is only suitable for steam turbine units of 600,000 or more with more valves. For feedwater pump steam turbines, its cost is relatively high, and it is easy to affect the reliability and stability of the control, resulting in poor practicality.

[0007] Therefore, it is necessary to provide a new technology to solve the above technical problems. Summary of the invention

[0008] The purpose of the present invention is to overcome the above-mentioned problems existing in the prior art and to provide a hydraulic speed control system for a feedwater pump turbine valve. The system can realize the replacement of the servo valve and the filter element online, avoiding shutdown for replacement of the servo valve and the filter element, and solves the technical problem of the existing regulating valve speed control system that the servo valve and the filter element cannot be replaced online, thereby effectively improving the reliability and economy of the unit.

[0009] To achieve the above purpose, the technical solution adopted by the present invention is as follows: A hydraulic speed control system for a feedwater pump steam turbine valve, comprising a regulating valve control unit, the regulating valve control unit comprising a regulating valve hydraulic control block and a regulating valve oil motor, the regulating valve hydraulic control block being fixedly provided with a servo valve, a filter, a hydraulically controlled one-way valve, a differential pressure cartridge unloading valve, an upper cartridge stop valve, a lower cartridge stop valve, a quick-closing solenoid valve, a pressure oil channel 1, an oil discharge channel 1 and a safety oil channel, the pressure oil channel 1 being connected to the oil inlet of the filter, the upper cartridge stop valve and the differential pressure cartridge unloading valve respectively; one end of the safety oil channel is connected to the pressure oil channel 1 through a safety oil throttle hole, and the other end is connected to the differential The control oil port of the pressure-type cartridge unloading valve is connected; the quick-closing solenoid valves are redundantly connected in parallel between the safety oil channel and the oil drain channel 1, and are used to control whether the safety oil channel and the oil drain channel 1 are connected; the oil inlet of the servo valve is connected to the filter, the control oil port of the servo valve is connected to the left oil port of the differential pressure type cartridge unloading valve through the hydraulically controlled one-way valve, the oil drain port of the servo valve is connected to the oil drain channel 1, the pilot oil port of the hydraulically controlled one-way valve is connected to the safety oil channel, and the right oil port of the differential pressure type cartridge unloading valve is connected to the lower cartridge stop valve; the rod chamber and the rodless chamber of the regulating valve oil motor are respectively connected to the upper cartridge stop valve and the lower cartridge stop valve.

[0010] A rodless cavity pressure measuring point A is provided between the differential pressure cartridge unloading valve and the hydraulically controlled one-way valve, and a rod cavity pressure measuring point B is provided between the upper cartridge stop valve and the first pressure oil passage.

[0011] The oil discharge channel 1 is provided with a one-way valve A and an oil discharge pressure measuring point, the oil discharge pressure measuring point is close to the fast 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.

[0012] A safety oil pressure measuring point is arranged on the safety oil passage.

[0013] The hydraulic speed control system also 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 divided into two outputs, one of which is connected to the pressure oil channel 1 through the ball valve A, and the other 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.

[0014] The oil drain pipe comprises an oil drain pipe, a pressure gauge, a pressure gauge stop valve and an oil drain stop valve. One end of the oil drain pipe is connected between the pressure oil stop valve and the accumulator bladder, and the other end is connected to the oil return port through the oil drain stop valve. The pressure gauge is connected to the oil drain pipe through the pressure gauge stop valve.

[0015] The hydraulic speed control system also includes a main steam valve control unit, which includes a main steam valve hydraulic control block and a main steam valve oil motor. A test solenoid valve, a shut-off solenoid valve, a test throttle hole, an oil drain channel 2 and a pressure oil channel 2 are fixedly arranged in the main steam valve hydraulic control block. One end of the pressure oil channel 2 is connected to the main pressure oil port through a ball valve B, and the other end is connected to the rod chamber of the main steam valve oil motor. One end of the oil drain channel 2 is used to connect to the return oil port, and the other end is connected to the rodless chamber of the main steam valve oil motor; the shut-off solenoid valve is redundantly connected in parallel between the oil drain channel 2 and the pressure oil channel 2, and is used to control whether the oil drain channel 2 is connected to the pressure oil channel 2; the test solenoid valve and the test throttle hole are connected to the pressure oil channel 2 in sequence, the oil drain port of the test solenoid valve is connected to the oil drain channel 2, and the test throttle hole is located between the test solenoid valve and the shut-off solenoid valve.

[0016] The second oil discharge channel is provided with a rodless cavity pressure measuring point C, and the second pressure oil channel is provided with a rod cavity pressure measuring point D.

[0017] A one-way valve C is provided on the second oil discharge channel, and the oil discharge port of the test solenoid valve is connected to the oil inlet end of the one-way valve C.

[0018] The advantages of adopting the present invention are: 1. The present invention adopts a specially structured regulating valve hydraulic control block and a regulating valve oil motor for coordinated control, which can realize the replacement of the servo valve and the filter element online, avoiding shutdown to replace the servo valve and the filter element, and solving the technical problem of the existing regulating valve speed control system that the servo valve and the filter element cannot be replaced online. It not only effectively improves the reliability and economy of the unit, but also brings indirect economic benefits to the power plant.

[0019] 2. The present invention adopts 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 the pressure pipeline when the regulating valve is quickly replenished with oil. In addition, the specific high-pressure energy storage unit only replenishes oil for the regulating valve oil motor, which is beneficial to reducing the size of the accumulator and reducing costs.

[0020] 3. The present invention adopts a main steam valve hydraulic control block and a main steam valve oil motor with a specific structure for the main steam valve. It controls the on-off of the safety oil by configuring two redundant two-position two-way blocking solenoid valves. The structure is simple and can reduce the investment cost of the owner. In addition, by optimizing the control solenoid valve logic, the main steam valve can be quickly closed and the non-stop caused by the malfunction of the fast-closing solenoid valve can be solved, which is beneficial to improving the economy of the unit.

[0021] 4. The present invention can monitor the pressure of each key point during the operation of the system in real time through various pressure measuring points, which is conducive to ensuring the safe, stable and reliable operation of the system.

[0022] 5. The present invention is provided with a one-way valve in both the regulating valve hydraulic control block and the main steam valve hydraulic control block. The one-way valve can prevent the oil discharged from other valves from flowing back into the corresponding oil motor, which is beneficial to avoid the system pressure reduction causing the unit to stop unexpectedly.

[0023] 6. The present invention eliminates the independent high-pressure shutoff device for safety oil. The installation position of the independent high-pressure shutoff device must be lower than the safety oil ports of all oil motors. The oil discharge port of the independent high-pressure shutoff device must be the return oil port of the high-pressure oil station. Otherwise, when the unit is shut down, the safety oil will not be drained smoothly due to the installation position of the high-pressure shutoff module, resulting in the unit's fast closing time not meeting national standards, and even causing the unit to run away. The present invention configures two redundant two-position two-way shutoff solenoid valves on the main steam valve and the regulating valve hydraulic control block to control the on-off of the safety oil, avoiding the above-mentioned problems caused by the inappropriate installation position of the independent high-pressure shutoff device. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a hydraulic control principle diagram of the regulating valve control unit in Example 1; Figure 2 This is a hydraulic control principle diagram of Example 2; Figure 3 This is a schematic diagram of the hydraulic control principle of the high-pressure energy storage unit in Example 2; Figure 4 This is a hydraulic control principle diagram of Example 3; Figure 5 This is the hydraulic control principle diagram of the main steam valve control unit in Example 3.

[0025] The markings in the figure are: 1. Hydraulic control block of regulating valve, 2. Oil motor of regulating valve, 3. Servo valve, 4. Filter, 5. Hydraulic control one-way valve, 6. Differential pressure cartridge unloading valve, 7. Upper cartridge stop valve, 8. Lower cartridge stop valve, 9. Quick closing solenoid valve, 10. Pressure oil channel 1, 11. Oil discharge channel 1, 12. Safety oil channel, 13. Rodless cavity pressure measuring point A, 14. Rod cavity pressure measuring point B, 15. One-way valve A, 16. Oil discharge pressure measuring point, 17. Safety oil pressure measuring point, 18. Safety oil throttle hole, 19. Ball valve A, 20. High-pressure energy storage unit, 21. Accumulator bladder , 22. Pressure oil stop valve, 23. Check valve B, 24. Oil drain pipe, 25. Pressure gauge, 26. Pressure gauge stop valve, 27. Oil drain stop valve, 28. Main steam valve hydraulic control block, 29. Main steam valve oil motor, 30. Test solenoid valve, 31. Shut-off solenoid valve, 32. Test throttle hole, 33. Oil drain channel 2, 34. Pressure oil channel 2, 35. Rodless cavity pressure measuring point C, 36. Rod cavity pressure measuring point D, 37. Check valve C, 38. Ball valve B, 39. Valve fully closed position travel switch, 40. Valve test position travel switch, 41. Valve fully open position travel switch. DETAILED DESCRIPTION

[0026] Example 1 like Figure 1 As shown, this embodiment provides a hydraulic speed control system for a feedwater pump turbine valve, the system includes a control valve control unit for controlling a control valve, the control valve control unit includes a control valve hydraulic control block 1 and a control valve oil motor 2. Among them, a servo valve 3, a filter 4, a hydraulically controlled one-way valve 5, a differential pressure cartridge unloading valve 6, an upper cartridge stop valve 7, a lower cartridge stop valve 8, a fast closing solenoid valve 9, a pressure oil passage 10, an oil discharge passage 11 and a safety oil passage 12 are fixedly arranged in the control valve hydraulic control block 1. The pressure oil passage 10 has a main oil inlet and multiple branches. The main oil inlet is connected to the main pressure oil port through an external ball valve A19, and the pressure oil passage 10 is connected to the oil inlets of the filter 4, the upper cartridge stop 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 hole 18, and the other end is connected to the control oil port of the differential pressure cartridge unloading valve 6; under the premise of ensuring economy and redundancy, the number of the quick-closing solenoid valves 9 is preferably two, and the two quick-closing solenoid valves 9 are redundantly connected in parallel between the safety oil passage 12 and the oil discharge passage 11 to control whether the safety oil passage 12 and the oil discharge passage 11 are connected. The oil inlet of the servo valve 3 is connected to the filter 4, the control oil port of the servo valve 3 is connected to the left oil port of the differential pressure cartridge unloading valve 6 through the hydraulic control check valve 5, the oil discharge port of the servo valve 3 is connected to the oil discharge passage 11, the pilot oil port of the hydraulic control check valve 5 is connected to the safety oil passage 12, and the right oil port of the differential pressure cartridge unloading valve 6 is connected to the lower cartridge stop valve 8. The rod chamber and the rodless chamber of the regulating valve oil motor 2 are connected to the upper cartridge stop valve 7 and the lower cartridge stop valve 8 respectively.

[0027] According to a preferred implementation of this embodiment, Figure 1 As shown, a rodless chamber pressure measuring point A13 is provided between the differential pressure cartridge unloading valve 6 and the hydraulically controlled one-way valve 5, a rod chamber pressure measuring point B14 is provided between the upper cartridge stop valve 7 and the pressure oil channel 10, a safety oil pressure measuring point 17 is provided on the safety oil channel 12, a one-way valve A15 and an oil discharge pressure measuring point 16 are provided on the oil discharge channel 11, and the oil discharge pressure measuring point 16 is close to the fast-closing solenoid valve 9, and the oil discharge port of the servo valve 3 is connected between the one-way valve A15 and the oil discharge pressure measuring point 16.

[0028] The hydraulic control principle of this embodiment is: The pressure oil enters the pressure oil passage 10 through the ball valve A19, and the pressure oil passes through the safety oil throttle hole 18 to form safety oil. Two redundant quick-closing solenoid valves 9 are installed between the safety oil passage 12 and the oil discharge passage 11 to control whether the safety oil passage 12 is connected to the oil discharge passage 11. The safety oil pressure measuring point 17 is set on the safety oil passage 12 to monitor the oil pressure of the safety oil. The built-in filter element filter 4 is set at the front end of the servo valve 3 to filter the impurities in the oil to prevent the servo valve 3 from getting stuck. The servo valve 3 adopts a double nozzle baffle structure with redundant coils. The hydraulically controlled one-way valve 5 is set on the pressure channel after the pressure oil enters the servo valve 3. The differential pressure cartridge unloading valve 6 is set on the pressure channel where the pressure oil enters the rodless chamber of the regulating valve oil motor 2. The rodless chamber pressure measuring point A13 and the rod chamber pressure measuring point B14 are respectively set on the pressure channel of the rodless chamber of the regulating valve oil motor 2 and the pressure channel of the rod chamber, which are used to monitor the pressure of the rodless chamber and the pressure of the rod chamber of the regulating valve oil motor 2. The lower cartridge stop valve is used to control the pressure oil in and out of the rodless chamber of the regulating valve oil motor 2, and the upper cartridge stop valve is used to control the pressure oil in and out of the rod chamber of the regulating valve oil motor 2. The oil discharge pressure measuring point 16 arranged on the oil discharge channel 11 is used to monitor the oil discharge pressure. The one-way valve A15 arranged on the oil discharge channel 11 is used to prevent the oil discharge from other valves from flowing back into the chamber of the regulating valve oil motor 2, causing the system pressure to drop and resulting in the unit's non-stop.

[0029] The usage method or workflow of this embodiment is as follows: Before the unit is shut down, the quick-closing solenoid valve 9 loses power, the safety oil channel 12 is connected to the oil discharge channel 11, the safety oil is not established, the hydraulically controlled one-way valve 5 can only conduct in one direction, and the pressure oil passes through the ball valve A19, the lower cavity of the differential pressure cartridge unloading valve 6 and the lower cartridge stop valve 8 to enter the rodless chamber of the regulating valve oil motor 2. At the same time, the pressure oil passes through the upper cartridge stop valve 7 to enter the rod chamber of the regulating valve oil motor 2. When the areas of the upper and lower chambers inside the regulating valve oil motor 2 are different, the force of the rodless chamber is greater than the force of the rod chamber, and the valve is in a closed state. At this time, the spring on the regulating valve actuator assists the valve to close.

[0030] After the unit is successfully locked, the two quick-closing solenoid valves 9 with redundant functions are energized, and the pressure oil passes through the ball valve A19 and the safety oil throttle hole 18 to form safety oil. The safety oil enters the hydraulically controlled one-way valve 5 through the pilot oil port, and the pilot oil circuit of the hydraulically controlled one-way valve 5 is opened. The hydraulically controlled one-way valve 5 is bidirectionally connected, and the safety oil enters the upper chamber of the differential pressure cartridge unloading valve 6. The control valve core moves downward to close the differential pressure cartridge unloading valve 6. At this time, the pressure oil is cut off and cannot enter the rodless chamber of the regulating valve oil motor 2. The rodless chamber of the regulating valve oil motor 2 is connected to the hydraulically controlled one-way valve 5 and the servo valve 3 through the left oil port and the right oil port of the differential pressure cartridge unloading valve 6. At this time, the oil inlet or outlet can be achieved through the servo command.

[0031] On the basis of the above, when the servo valve 3 receives the door opening command, the control oil port B of the servo valve 3 is connected to the oil discharge port T, and the oil pressure in the rodless chamber of the regulating valve oil motor 2 is released. Under the action of the oil pressure in the rod chamber of the regulating valve oil motor 2, the valve gradually opens until the valve opening reaches the given command opening position, and the servo valve 3 automatically centers and maintains its position. When the servo valve 3 receives the door closing command, the oil inlet P of the servo valve 3 is connected to the control oil port B, and the regulating valve oil motor 2 gradually closes under the force difference between the upper and lower chambers. When the given command position is reached, the servo valve 3 automatically centers and maintains its position.

[0032] On the basis of the above, when the unit receives a trip signal, the two quick-closing solenoid valves 9 with redundant functions of the regulating valve oil motor 2 lose power at the same time, the safety oil channel 12 is connected to the oil discharge channel 11, and the safety oil in the upper chamber of the differential pressure cartridge unloading valve 6 is depressurized through the oil discharge channel 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 oil motor 2 through the differential pressure cartridge unloading valve 6. At this time, the hydraulically controlled one-way valve 5 can only be unidirectionally conducted. Under the force difference between the upper and lower chambers and the cooperation of the spring, the regulating valve of the regulating valve oil motor 2 is quickly closed.

[0033] Furthermore, when the unit is operating normally, when the filter element of the filter 4 has a differential pressure alarm, the filter element can be replaced online, and the replacement process is as follows: First, the valve position of the regulating valve is relatively stable, and the servo valve 3 is in the middle position. First, close the lower plug-in stop valve 8, then close the upper plug-in stop valve 7, to achieve the valve position holding function, and then close the ball valve A19 on the pressure oil circuit to cut off the continuous supply of pressure oil, so that any one of the two redundant fast-closing solenoid valves 9 loses power for 2s and then resets to be energized, the purpose of which is to release the internal pressure of the hydraulic control block 1 of the regulating valve. Then remove the filter 4 that has issued an alarm signal, replace it with a new filter element, and after completing the filter element replacement work, open the ball valve A19 to allow pressure oil to enter, and restore the pressure of the safety oil through the safety oil throttle hole 18. The safety oil pressure measuring point 17 on the safety oil circuit determines whether the differential pressure cartridge unloading valve 6 is successfully closed. When the differential pressure cartridge unloading valve 6 is closed, open the upper plug-in stop valve 7 and the lower plug-in stop valve 8 at the same time to restore the unit to a normal state.

[0034] Furthermore, when the unit is operating normally, if the servo valve 325 fails, the servo valve 3 can be replaced online, and the replacement process is as follows: When the unit is operating normally, if servo valve 3 fails, first shield the output of the servo card command. First close the lower plug-in stop valve 8, then close the upper plug-in stop valve 7 to realize the valve position holding function, and then close the ball valve A19 on the pressure oil circuit to cut off the continuous supply of pressure oil, so that any one of the two redundant fast-closing solenoid valves 9 loses power for 2s and then resets to be energized, the purpose of which is to release the internal pressure of the hydraulic control block 1 of the regulating valve.

[0035] Then dismantle the failed servo valve 3 and replace it with a new servo valve 3. After completing the replacement of the servo valve 3, open the ball valve A19 to allow the pressure oil to enter, and restore the pressure of the safety oil through the safety oil throttle hole 18. Use the safety oil pressure measuring point 17 to determine whether the differential pressure cartridge unloading valve 6 is successfully closed. When the differential pressure cartridge unloading valve 6 is closed, open the upper cartridge stop valve 7 and the lower cartridge stop valve 8 at the same time, reset the servo card and restore the unit to a normal state.

[0036] This embodiment can also detect whether the safety oil is successfully established, specifically by checking the pressure of the safety oil pressure measuring point 17 on the safety oil channel 12 and the pressure of the oil discharge pressure measuring point 16 on the oil discharge channel 11 to determine whether the safety oil throttle hole 18 is blocked or there is a problem with the fast closing solenoid valve 9.

[0037] Example 2 like Figure 2 , 3 As shown, this embodiment adds a high-pressure energy storage unit 20 on the basis of 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, and the oil outlet of the one-way valve B23 is divided into two outputs, one is connected to the pressure oil channel 10 through the ball valve A19, and the other 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.

[0038] Furthermore, the oil drain pipe includes an oil drain pipe 24, a pressure gauge 25, a pressure gauge stop valve 26 and an oil drain stop valve 27. One end of the oil drain pipe 24 is connected between the pressure oil stop valve 22 and the accumulator bladder 21, and the other end is connected to the oil return port through the oil drain stop valve 27. The pressure gauge 25 is connected to the oil drain pipe 24 through the pressure gauge stop valve 26. The pressure gauge 25 is used to check the oil pressure in the pressure channel. The pressure gauge stop valve 26 is set in front of the oil inlet of the pressure gauge 25 to cut off the pressure oil when replacing the pressure gauge 25.

[0039] When the unit is operating normally, the pressure gauge stop valve 26 and the pressure oil stop valve 22 are opened, and the oil drain stop valve 27 is closed. The system pressure oil passes through the one-way valve B23, and part of it enters the accumulator bladder 21 to store energy, and part of it enters the regulating valve oil motor 2 through the ball valve A19. When the unit is operating normally, the accumulator bladder 21 can absorb hydraulic shock and reduce pulsation. When the regulating valve needs to be opened quickly, the accumulator bladder 21 can be used as an auxiliary power source to replenish oil to the regulating valve oil motor 2, which can prevent the system from vibrating the pipeline and the regulating valve due to a large amount of oil replenishment. Vibration.

[0040] The present embodiment can also realize online replacement of the accumulator bladder 21. If the accumulator bladder 21 is damaged, first close the pressure oil stop valve 22 without affecting the normal operation of the unit, open the oil drain stop valve 27, and allow the pressure oil in the accumulator bladder 21 to be connected to the return oil port through the oil drain pipe 24. After the oil in the accumulator bladder 21 is completely returned to the oil tank, close the oil drain stop valve 27 and replace it with a new accumulator bladder 21. After the replacement of the bladder is completed, open the pressure oil stop valve 22 to allow the pressure oil to enter the accumulator bladder 21 to store energy and restore the function of the high-pressure accumulator.

[0041] Example 3 In this embodiment, a main steam valve control unit is added on the basis of Embodiments 1 and 2. Usually, the feedwater pump turbine includes two main steam valves, so two sets of main steam valve control units are added. The 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, so as to control the opening of the two main steam valves respectively.

[0042] 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 oil motor 29. A test solenoid valve 30, a shutoff solenoid valve 31, a test throttle hole 32, a drain channel 2 33 and a pressure oil channel 2 34 are fixedly arranged in the main steam valve hydraulic control block 28. One end of the pressure oil channel 2 34 is connected to the main pressure oil port through a ball valve B38, and the other end is connected to the rod chamber of the main steam valve oil motor 29. One end of the drain channel 2 33 is used to connect to the oil return port, and the other end is connected to the rodless chamber of the main steam valve oil motor 29. There can be two shutoff solenoid valves 31, and the two shutoff solenoid valves 31 are redundantly connected in parallel between the drain channel 2 33 and the pressure oil channel 2 34, and are used to control whether the drain channel 2 33 and the pressure oil channel 2 34 are connected. The test solenoid valve 30 and the test throttle hole 32 are connected to the pressure oil channel 34 in sequence. The oil discharge port of the test solenoid valve 30 is connected to the oil discharge channel 33. The test throttle hole 32 is located between the test solenoid valve 30 and the shut-off solenoid valve 31.

[0043] According to a preferred implementation of this embodiment, Figure 4 , 5As shown, a rod chamber pressure measuring point D36 is provided on the pressure oil channel 2 34, a rodless chamber pressure measuring point C35 and a one-way valve C37 are provided on the oil discharge channel 2 33, the rodless chamber pressure measuring point C35 is located between the one-way valve C37 and the rodless chamber of the main steam valve oil motor 29, and the oil discharge port of the test solenoid valve 30 is connected to the oil inlet end of the one-way valve C37.

[0044] The hydraulic control principle of this embodiment is: The pressure oil enters the main steam valve hydraulic control block 28 through the ball valve B38. The test solenoid valve 30 is installed on the pressure oil passage 2 34. The test throttle hole 32 is installed at the control oil port A of the test solenoid valve 30. The speed of oil inlet and outlet is controlled by adjusting the size of the test throttle hole 32. Two cut-off solenoid valves 31 are redundantly configured to control whether the pressure oil is connected to the oil outlet passage 2 33. The rodless chamber pressure measuring point C35 and the rod chamber pressure measuring point D36 are used to monitor the oil pressure of the rodless chamber and the rod chamber on the main steam valve oil motor 29. The check valve C37 is used to prevent the oil discharged from other valves from flowing back into the chamber of the main steam valve oil motor 29. The main steam valve is equipped with two valve full-close position travel switches 39 for monitoring the full-close signal of the main steam valve; a valve full-open travel switch is also configured to monitor the full-open signal of the main steam valve; and a valve test position travel switch 40 is also configured for valve activity testing to check whether the main steam valve is stuck.

[0045] The usage method or workflow of this embodiment is as follows: The unit is successfully shut down, the test solenoid valve 30 is energized, the pressure oil is cut off by the test solenoid valve 30, the two shut-off solenoid valves 31 are energized, the pressure oil channel 2 34 and the oil discharge channel 2 33 are not conducting, and the conditions for valve opening are met at this time, the main steam valve is in a fully closed state, and the two valves are in the fully closed position. The stroke switch 39 sends a signal; when the test solenoid valve 30 loses power, 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 oil motor 29 through the test throttle hole 32. Under the action of the pressure oil, the valve gradually opens to overcome the resistance until the valve is fully open. At this time, the valve fully open position stroke switch 41 sends a signal.

[0046] On the basis of the above, the valve activity test is carried out, and the test solenoid valve 30 is energized (the solenoid valve A port is connected to the T port). 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 oil motor 29 is connected to the oil discharge channel 2 33 through the test solenoid valve 30, and the oil in the rod chamber of the main steam valve oil motor 29 enters the oil tank through the test throttle hole 32 and the oil discharge channel 2 33, and the valve gradually closes. When the valve test position stroke switch 40 sends a signal, the test solenoid valve 30 automatically loses power, and the pressure oil enters the rod chamber of the main steam valve oil motor 29 through the test solenoid valve 30A port, and the valve gradually returns to full opening. At this time, the full open position stroke switch sends a signal.

[0047] On the basis of the above, when the two mutually redundant isolation solenoid valves 31 receive the unit trip signal, the two isolation solenoid valves 31 lose power at the same time, the pressure oil channel 2 34 and the oil discharge channel 2 33 are connected, and the valves are quickly closed under the action of the spring.

[0048] The above description is only a specific implementation mode of the present invention. Any feature disclosed in this specification, unless otherwise stated, can be replaced by other alternative features that are equivalent or have similar purposes; all the disclosed features, or all the steps in the methods or processes, except for mutually exclusive features and / or steps, can be combined in any way.

Claims

1. A hydraulic speed control system for a feedwater pump turbine valve, characterized in that: The invention comprises a regulating valve control unit, the regulating valve control unit comprising a regulating valve hydraulic control block (1) and a regulating valve oil motor (2), wherein a servo valve (3), a filter (4), a hydraulically controlled one-way valve (5), a differential pressure cartridge unloading valve (6), an upper cartridge stop valve (7), a lower cartridge stop valve (8), a quick-closing solenoid valve (9), a pressure oil passage (10), an oil discharge passage (11) and a safety oil passage (12) are fixedly arranged in the regulating valve hydraulic control block (1), wherein the pressure oil passage (10) is respectively connected to the oil inlet of the filter (4), the upper cartridge stop valve (7) and the differential pressure cartridge unloading valve (6); one end of the safety oil passage (12) is connected to the pressure oil passage (10) through a safety oil throttle hole (18), and the other end is connected to the differential pressure cartridge unloading valve (6) ); the quick-closing solenoid valve (9) is redundantly connected in parallel between the safety oil passage (12) and the oil discharge passage 1 (11) to control whether the safety oil passage (12) and the oil discharge passage 1 (11) are connected; the oil inlet of the servo valve (3) is connected to the filter (4); the control oil port of the servo valve (3) is connected to the left oil port of the differential pressure cartridge unloading valve (6) through the hydraulic control check valve (5); the oil discharge port of the servo valve (3) is connected to the oil discharge passage 1 (11); the pilot oil port of the hydraulic control check valve (5) is connected to the safety oil passage (12); the right oil port of the differential pressure cartridge unloading valve (6) is connected to the lower cartridge stop valve (8); the rod chamber and the rodless chamber of the regulating valve oil motor (2) are respectively connected to the upper cartridge stop valve (7) and the lower cartridge stop valve (8).

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

3. The hydraulic speed control system for a feedwater pump turbine valve according to claim 1, characterized in that: The oil discharge channel 1 (11) is provided with a one-way valve A (15) and an oil discharge pressure measuring point (16). The oil discharge pressure measuring point (16) is close to the fast-closing solenoid valve (9). The oil discharge port of the servo valve (3) is connected between the one-way valve A (15) and the oil discharge 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 provided 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: The invention also includes a high-pressure energy storage unit (20), wherein the high-pressure energy storage unit (20) includes an accumulator bladder (21), a pressure oil stop valve (22), a one-way valve B (23) and an oil discharge pipe (24). The oil inlet of the one-way valve B (23) is connected to the main pressure oil port, and the oil outlet of the one-way valve B (23) is divided into two outputs, one of which is connected to the pressure oil channel 1 (10) through the ball valve A (19), and the other is connected to the accumulator bladder (21) through the pressure oil stop valve (22). The oil discharge pipe (24) is connected between the pressure oil stop valve (22) and the accumulator bladder (21).

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

7. A hydraulic speed control system for a feedwater pump turbine valve according to any one of claims 1 to 6, characterized in that: It also includes a main steam valve control unit, the main steam valve control unit including a main steam valve hydraulic control block (28) and a main steam valve oil motor (29), the main steam valve hydraulic control block (28) is fixedly provided with a test solenoid valve (30), a shut-off solenoid valve (31), a test throttle hole (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 through a ball valve B (38), and the other end is connected to the rod chamber of the main steam valve oil motor (29), and one end of the second oil discharge channel (33) is used to connect to the oil return port The first end of the solenoid valve (31) is connected to the second oil discharge channel (33) and the second pressure oil channel (34), and the other end is connected to the rodless chamber of the main steam valve oil motor (29); the shut-off solenoid valve (31) is redundantly connected in parallel between the second oil discharge channel (33) and the second pressure oil channel (34), and is 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 hole (32) are connected to the second pressure oil channel (34) in sequence, the oil discharge port of the test solenoid valve (30) is connected to the second oil discharge channel (33), and the test throttle hole (32) is located between the test solenoid valve (30) and the shut-off solenoid valve (31).

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

9. The hydraulic speed control system for a feedwater pump turbine valve according to claim 7, characterized in that: The second oil discharge channel (33) is provided with a one-way valve C (37), and the oil discharge 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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