Pumping and storage tail gate hydraulic system capable of automatically closing door without electricity
By designing a hydraulic system for tail storage gates including hydraulic cylinders, locking cylinders, hydraulic reversing valves and reversing valves, the problem of unable to automatically close the tail water accident gate when there is no electricity or operation is difficult in the prior art, and the safety effect of automatic door closing without electricity is achieved.
Patent Information
- Application Number
- CN202421719612.1
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-07-19
- Publication Date
- 2025-05-16
- Estimated Expiration
- 2034-07-19
AI Technical Summary
The existing tail gate hydraulic system cannot automatically close the tail gate when there is no electricity or difficult to operate, resulting in safety risks.
A tail gate hydraulic system including hydraulic cylinder, locking cylinder, hydraulic reversing valve and reversing valve group is designed. The hydraulic pipeline of the locking cylinder is controlled through the hydraulic reversing valve and reversing valve group to realize the automatic door closing function without electricity.
It realizes automatic closing of the tailwater accident gate in the absence of electricity, avoids malfunctions, and improves the safety of the pumped storage power station.
Smart Images
Figure CN222880487U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to a hydraulic system for a pumped-storage tailgate capable of automatically closing the door without electricity, and is applicable to the field of pumped-storage engineering. Background Art
[0002] The pumped storage power station unit has a large suction height and a low installation elevation. It bears a high head from the lower reservoir. The valves and pipes connected to the unit flow channel are under great pressure. Most of the water supply in the plant is drawn from the lower reservoir. Once the pipes and valves connected to the flow channel leak, there will be a risk of flooding the plant. Therefore, an emergency gate is generally set behind the water intake of the tailwater pipeline unit. The emergency gate is opened and closed by static water when the unit guide vane and its upstream water inlet valve are closed. When the water supply pipe or valve of the unit auxiliary system fails, it can be closed by dynamic water in time to cut off the water from the lower reservoir, prevent the accident from expanding, and improve the safety of the pumped storage power station.
[0003] The tailwater accident gate is operated by a hydraulic hoist and is designed to withstand the head of the lower reservoir, but cannot withstand the head of the upper reservoir. For safety reasons, there is a strict locking relationship between it and the unit's inlet valve. The tailwater gate can only be operated (dropped) when the main inlet valve is fully closed and its downstream seal is put into operation. The inlet valve can only be operated (opened) when the tailwater gate is fully opened. When the tailwater gate falls abnormally, the inlet valve should be able to immediately close ahead of the tailwater gate.
[0004] At present, most tailgate hydraulic systems close the gate under DC power supply according to AC power failure (i.e. the hydraulic pump group does not start). When DC power is lost, the gate is closed by manually opening the normally closed ball valve on the hydraulic system. The gate is electrically interlocked with the main engine water inlet valve, and the two control systems monitor each other. The premise of this technical solution is that there is absolutely reliable DC power or people can reach the tailgate hole for operation. If there is no DC power or the personnel cannot enter the tailgate hole for operation due to water inflow, the tailwater accident gate cannot be closed as required. Utility Model Content
[0005] The technical problem to be solved by the utility model is: in view of the above existing problems, a pumped storage tail gate hydraulic system capable of automatically closing the door without electricity is provided.
[0006] The technical solution adopted by the utility model is: a hydraulic system for pumped storage tailgate capable of automatically closing the door without electricity, characterized in that it includes:
[0007] Hydraulic cylinder, used to drive the tailwater gate to open or close;
[0008] A locking cylinder, wherein when the piston inside the locking cylinder is located at the left end of the cylinder body, the locking cylinder can lock the piston rod of the hydraulic cylinder in the fully open position of the tailwater gate;
[0009] A hydraulic reversing valve is connected to the hydraulic oil return pipeline of the locking cylinder, and its hydraulic control port is connected to the unit water inlet valve, which can disconnect the hydraulic oil return pipeline of the locking cylinder from the oil tank when the unit water inlet valve is opened, and connect the hydraulic oil return pipeline of the locking cylinder to the oil tank when the unit water inlet valve is closed;
[0010] The reversing valve group is connected to the hydraulic pipeline of the locking cylinder. When the reversing valve group is energized and the hydraulic reversing valve is connected, the piston in the locking cylinder can move toward the left end of the locking cylinder through the hydraulic pipeline. When the reversing valve group is de-energized and the hydraulic reversing valve is connected, the piston in the locking cylinder can move toward the right end through the hydraulic pipeline.
[0011] Also includes:
[0012] A two-way cartridge valve is connected to the hydraulic pipeline of the hydraulic cylinder, and its control oil port is connected to the control pipeline, and the control pipeline is connected to the roller reversing valve. When the roller reversing valve is disconnected, the two-way cartridge valve is closed, and when the roller reversing valve is connected, the two-way cartridge valve is opened;
[0013] The roller of the roller reversing valve is driven by the locking cylinder. When the piston of the locking cylinder is at the left end, the locking cylinder has no thrust on the roller, and the roller reversing valve is disconnected; when the piston of the locking cylinder is at the right end, the locking cylinder has thrust on the roller, and the roller reversing valve is connected.
[0014] A pressure plate is mounted on the piston rod of the locking cylinder, and the pressure plate is arranged corresponding to the roller of the roller reversing valve.
[0015] The control pipeline comprises a first pipeline and a second pipeline, wherein one end of the first pipeline is connected to the rod chamber of the hydraulic cylinder, and the other end is connected to the control oil port of the two-way cartridge valve;
[0016] One end of the second pipeline is connected to the first pipeline, and the other end is connected to the oil tank. The roller reversing valve is installed on the second pipeline.
[0017] Also includes:
[0018] The gate position monitoring module is used to collect the position information of the tailwater gate and is connected to the control module circuit of the unit water inlet valve.
[0019] The gate position monitoring module is connected to the control module circuit of the reversing valve group.
[0020] The gate position monitoring module includes a position switch SQ1 corresponding to the fully open position of the tailwater gate, a position switch SQ2 located a certain distance below the position switch SQ1, and a position switch SQ3 located a certain distance below the position switch SQ2.
[0021] The position switch SQ2 includes a position switch SQ2.1 and a position switch SQ2.2 located before and after the tailwater gate, and the position switch SQ3 includes a position switch SQ3.1 and a position switch SQ3.2 located before and after the tailwater gate;
[0022] The two signals of the position switches SQ2.1 and SQ2.2 are first connected in parallel, and the two signals of the position switches SQ3.1 and SQ3.2 are also first connected in parallel. The two parallel signals of the position switches SQ2 and SQ3 are then used in series.
[0023] The reversing valve group includes two ball reversing valves a and two ball reversing valves b, wherein the ball reversing valve a is connected to the rod chamber of the hydraulic cylinder via the third pipeline, connected to the oil tank via the fourth pipeline, and connected to the right chamber of the locking cylinder via the fifth pipeline;
[0024] The ball-type reversing valve b is connected to the rod chamber of the hydraulic cylinder via the third pipeline, connected to the oil tank via the fourth pipeline, and connected to the left chamber of the locking cylinder via the sixth pipeline.
[0025] The oil circuits of the two ball-type reversing valves a are connected in series when the electromagnet is powered off, and the oil circuits of the two ball-type reversing valves b are also connected in series when the electromagnet is powered off. When the gate is in the fully open state and the unit water inlet valve is in the process of opening, and the tailwater accident gate and the unit water inlet valve have not yet formed a mechanical lock, as long as the four ball-type reversing valves do not accidentally lose power at the same time, the gate will not be mistakenly closed, thereby avoiding accidents.
[0026] The beneficial effects of the utility model are as follows: the utility model controls the hydraulic pipeline of the locking cylinder through the reversing valve group and the hydraulic reversing valve. When the reversing valve group loses power and the water inlet valve of the unit is closed, the piston in the locking cylinder moves to the right end, and the hydraulic cylinder can be unlocked. After the unlocking is in place, the roller reversing valve is actuated, and the oil in the rod chamber of the hydraulic cylinder returns to the rodless chamber, and the gate is closed, realizing the requirement that the unlocking and closing of the gate must be performed in sequence when there is no electricity to close the door. The utility model realizes mechanical locking with the water inlet valve of the unit through the hydraulic reversing valve, avoids the malfunction of automatically closing the gate when there is no electricity, and the hydraulic system principle and electrical control are simple and reliable, ensuring the safety of the water delivery system of the pumped storage power station.
[0027] The utility model makes the hydraulic pipeline of the locking cylinder form a unlocking circuit after the reversing valve group loses power. When the piston in the locking cylinder is at the right end, the locking cylinder has a thrust on the roller, and the roller reversing valve is connected, so that the two-way cartridge valve on the rod chamber circuit of the hydraulic cylinder controls the port to return to the oil tank, and the rod chamber of the hydraulic cylinder is connected to the oil tank, so that the gate can be automatically closed without electricity.
[0028] In the utility model, the oil return pipeline of the locking cylinder is connected with the water inlet valve of the unit through the hydraulically controlled reversing valve. When the water inlet valve of the unit is opened, the oil return pipeline of the locking cylinder is disconnected from the oil tank, and the gate cannot be closed. Even if the reversing valve group loses power accidentally, the gate will not close, thereby preventing the automatic door closing from malfunctioning without power.
[0029] The utility model provides an opening signal for the unit water inlet valve and an emergency valve closing signal when the gate falls accidentally through the gate position monitoring module. In the utility model, two signals at each position of the gate falling accidentally are first connected in parallel, and the two parallel signals are then used in series to avoid the accidental fall monitoring position switch from not sending a signal or sending a signal by mistake. BRIEF DESCRIPTION OF THE DRAWINGS
[0030] Figure 1 It is a schematic diagram of the hydraulic system of an embodiment.
[0031] 1. Hydraulic cylinder; 2. Oil tank; 3. Control valve group; 4. Two-way cartridge valve; 5. Hydraulic control reversing valve; 6. Oil tank; 7. Ball reversing valve a; 8. Ball reversing valve b; 9. Position switch SQ1; 10. Position switch SQ2; 11. Position switch SQ3; 12. Roller reversing valve; 13. Pressure plate; 14. Locking cylinder. DETAILED DESCRIPTION
[0032] The present embodiment is a hydraulic system for a pumped storage tailgate that can automatically close the door without electricity, including a hydraulic cylinder, an oil replenishing tank, a control valve group, a roller reversing valve, a locking cylinder, etc., wherein the control valve group includes a two-way cartridge valve, a hydraulic reversing valve, a ball reversing valve a and a ball reversing valve b, etc.
[0033] In this example, the piston rod of the hydraulic cylinder is connected to the tailwater gate, and the hydraulic cylinder can be used to drive the tailwater gate to open or close the gate.
[0034] In this embodiment, the locking cylinder can be used to lock the hydraulic cylinder. When the piston in the locking cylinder is located at the left end of the cylinder body, the locking cylinder can lock the piston rod of the hydraulic cylinder in the fully open position of the tailwater gate, so that the piston rod of the hydraulic cylinder is in a locked state; when the piston in the locking cylinder is located at the right end of the cylinder body, the locking cylinder unlocks the lock of the hydraulic cylinder, and the piston rod of the hydraulic cylinder is in an unlocked state.
[0035] In this embodiment, the hydraulic pipeline of the locking cylinder includes the third pipeline, the fourth pipeline, the fifth pipeline and the sixth pipeline; the reversing valve group includes two ball reversing valves a and two ball reversing valves b. The oil circuits of the two ball reversing valves a form a series connection when the electromagnet is powered off, and the oil circuits of the two ball reversing valves b also form a series connection when the electromagnet is powered off. When the gate is in the fully open state and the unit water inlet valve is in the process of opening, the tailwater accident gate and the unit water inlet valve have not yet formed a mechanical lock, as long as the four ball reversing valves do not lose power at the same time, the gate will not be mistakenly closed, avoiding accidents. In this example, the ball reversing valve a is connected to the rod chamber of the hydraulic cylinder through the third pipeline, connected to the oil tank through the fourth pipeline, and connected to the right chamber of the locking cylinder through the fifth pipeline. The ball reversing valve b is connected to the rod chamber of the hydraulic cylinder through the third pipeline, connected to the oil tank through the fourth pipeline, and connected to the left chamber of the locking cylinder through the sixth pipeline.
[0036] When the electromagnets of the ball reversing valve a and the ball reversing valve b are energized, the ball reversing valves a and b connect the third pipeline with the fifth pipeline, and the fourth pipeline with the sixth pipeline, and the hydraulic pipeline of the locking cylinder forms a locking circuit. The pressure oil in the rod chamber of the hydraulic cylinder acts on the right chamber of the locking cylinder, and the piston rod of the locking cylinder moves to the left. The oil in the left chamber of the locking cylinder returns to the oil tank. At this time, the locking cylinder can put the piston rod of the hydraulic cylinder in a locked state.
[0037] When the solenoids of ball reversing valve a and ball reversing valve b lose power, ball reversing valves a and b connect the third pipeline with the sixth pipeline, and the fourth pipeline with the fifth pipeline, and the hydraulic pipeline of the locking cylinder forms an unlocking circuit. The pressure oil in the rod chamber of the hydraulic cylinder acts on the left chamber of the locking cylinder, and the piston rod of the locking cylinder moves to the right. The oil in the right chamber of the locking cylinder returns to the oil tank. At this time, the locking cylinder releases the lock on the piston rod, and the piston rod of the hydraulic cylinder is in an unlocked state.
[0038] Compared with the sliding valve, the ball reversing valve has better sealing performance and no leakage. Therefore, the present embodiment adopts the ball reversing valve a and the ball reversing valve b to avoid the gate sliding down in the fully open position and frequently starting the automatic reset program.
[0039] In this example, a hydraulic reversing valve is connected to the fourth pipeline in the locking cylinder hydraulic pipeline, and the hydraulic control port of the hydraulic reversing valve is connected to the unit water inlet valve. When the unit water inlet valve is opened, there is pressure in the hydraulic control port, and the hydraulic reversing valve disconnects the fourth pipeline, the return oil circuit of the locking cylinder is disconnected from the oil tank, and the gate is not in a condition to close; when the unit water inlet valve is closed, there is no pressure in the hydraulic control port, and the hydraulic reversing valve is reset under the action of the spring force, so that the fourth pipeline is connected, the return oil circuit of the locking cylinder is connected to the oil tank, and the gate is in a condition to close. Compared with the original electrical interlock between the tail gate and the unit water inlet valve, the technical solution of the utility model also realizes a mechanical interlock between the two to prevent malfunction when the gate is automatically closed without electricity.
[0040] In this embodiment, the rodless chamber of the locking cylinder is connected to the oil tank via the seventh pipeline, and the rod chamber of the locking cylinder is connected to the oil tank via the eighth pipeline, wherein the eighth pipeline is connected to a two-way cartridge valve.
[0041] In this example, the control oil port of the two-way cartridge valve is connected to a control pipeline, which has a first pipeline and a second pipeline, wherein one end of the first pipeline is connected to the rod chamber of the hydraulic cylinder, and the other end is connected to the control oil port of the two-way cartridge valve; one end of the second pipeline is connected to the first pipeline, and the other end is connected to the oil tank, and a roller reversing valve is installed on the second pipeline.
[0042] In this embodiment, the roller reversing valve is connected to the second pipeline through its a and b ports. The roller of the roller reversing valve is driven by the locking cylinder. When the piston of the locking cylinder is at the left end, the locking cylinder has no thrust on the roller, and the a and b ports of the roller reversing valve are disconnected; when the piston of the locking cylinder is at the right end, the locking cylinder has thrust on the roller, and the a and b ports of the roller reversing valve are connected.
[0043] In this embodiment, the roller reversing valve is arranged near the locking cylinder and parallel to the locking cylinder. A pressure plate is installed on the piston rod of the locking cylinder. The pressure plate corresponds to the roller of the roller reversing valve. The locking cylinder can push the roller of the roller reversing valve through the pressure plate.
[0044] Port a of the roller reversing valve is connected to the control oil port of the two-way cartridge valve, and port b of the roller reversing valve returns to the oil tank. When there is no thrust on the roller side of the roller reversing valve, port a is disconnected from port b, the two-way cartridge valve is closed, and the gate cannot be closed; when the roller of the roller reversing valve is pushed by the pressure plate, port a and port b are connected, the two-way cartridge valve is opened, and the gate can be closed.
[0045] In this embodiment, a gate position monitoring module for collecting position information of the tailwater gate is provided, and the gate position monitoring module is circuit-connected with the control module of the unit water inlet valve and the control module of the reversing valve group.
[0046] In this example, the gate position monitoring module includes a position switch SQ1 corresponding to the fully open position of the tailwater gate, a position switch SQ2 located a certain distance below the position switch SQ1, and a position switch SQ3 located a certain distance below the position switch SQ2.
[0047] In this embodiment, the position switch SQ1 includes a position switch SQ1.1 and a position switch SQ1.2 located before and after the tailwater gate; the position switch SQ2 includes a position switch SQ2.1 and a position switch SQ2.2 located before and after the tailwater gate; the position switch SQ3 includes a position switch SQ3.1 and a position switch SQ3.2 located before and after the tailwater gate.
[0048] In this example, the two signals of position switches SQ2.1 and SQ2.2 are first connected in parallel, and the two signals of position switches SQ3.1 and SQ3.2 are also first connected in parallel. The two parallel signals of position switches SQ2 and SQ3 are then used in series.
[0049] In this embodiment, when the gate is opened to a certain distance from the fully open position, the position switches SQ1.1 and SQ1.2 are activated, indicating that the gate is in the open state and the unit water inlet valve can be opened. The position switch circuit is connected when the gate is fully open, and the circuit is disconnected when the gate falls. In order to prevent the gate from sliding down to the automatic reset position due to leakage in the system at the fully open position, and the gate fully open signal does not disappear, the installation position of the position switches SQ1.1 and SQ1.2 should be lower than the gate automatic reset distance set in the electrical control program.
[0050] In this example, position switches SQ2.1, SQ2.2 and position switches SQ3.1, SQ3.2 can provide signals to the unit's water inlet valve, indicating that the tailwater gate has fallen abnormally and unexpectedly, and the water inlet valve is immediately closed before the tailwater gate. The position switches SQ2.1 and SQ2.2 are set at a position lower than the installation position of position switches SQ1.1 and SQ1.2, and the position switches SQ3.1 and SQ3.2 are set at a position lower than the installation position of position switches SQ2.1 and SQ2.2. The two signals of SQ2.1 and SQ2.2 are first connected in parallel, and the two signals of SQ3.1 and SQ3.2 are also first connected in parallel, and the two parallel signals of SQ2 and SQ3 are then used in series.
[0051] In this embodiment, the position switches SQ2.1, SQ2.2 and the position switches SQ3.1, SQ3.2 are used to monitor the accidental fall of the gate. The parallel and series connection can avoid the accidental fall monitoring position switches from not sending signals or sending signals by mistake.
[0052] The gate automatically closes when there is no electricity: when there is no electricity in the entire power station, the water inlet valve of the unit will automatically close, the hydraulic reversing valve will change direction under the action of the spring, and the oil return line of the locking cylinder will be connected to the oil tank. At this time, the electromagnets of the ball reversing valve a and the ball reversing valve b have been automatically powered off, and the pressure oil in the rod chamber of the hydraulic cylinder enters the left chamber of the locking cylinder, and the oil in the right chamber of the locking cylinder returns to the oil tank. When the piston rod of the locking cylinder moves to the right until the pressure plate contacts the roller of the roller reversing valve, the roller reversing valve changes direction, the pressure of the control port of the two-way cartridge valve returns to the oil tank, the oil in the rod chamber of the hydraulic cylinder returns to the rodless chamber, and the oil replenishing tank automatically replenishes oil to the rodless chamber, and the gate closes automatically.
[0053] The gate is closed normally: the unit's water inlet valve is in the closed state, the hydraulic reversing valve changes direction under the action of the spring, the locking cylinder's oil return line is connected to the oil tank, and after the tail gate electrical control program receives the unit's water inlet valve full-close signal, the electromagnets of the ball reversing valve a and the ball reversing valve b are de-energized, and the gate automatically closes in place, and the hydraulic system shuts down.
[0054] The gate is opened: the water inlet valve of the unit is in the closed state, the hydraulic reversing valve is reversed under the action of the spring, the oil return line of the locking cylinder is connected to the oil tank, the electromagnets of the ball reversing valve a and the ball reversing valve b are powered off, the pump group in the oil tank is powered on to build pressure, and the pressure oil enters the rod chamber of the hydraulic cylinder through the control valve group. The oil in the rodless chamber of the hydraulic cylinder is first replenished to the oil tank, and the liquid level switch on the replenishment tank is actuated, and the oil in the rodless chamber of the hydraulic cylinder is then returned to the oil tank, the position switches SQ1.1 and SQ1.2 are actuated, the electromagnets of the ball reversing valve a and the ball reversing valve b are energized, and the pressure oil enters the right chamber of the locking cylinder. The piston rod of the hydraulic cylinder is in a mechanically locked state. After the gate is fully opened, the tail gate hydraulic system is shut down, but the electromagnets of the ball reversing valve a and the ball reversing valve b are always energized. At this time, the water inlet valve of the unit is opened, there is pressure at the control port of the hydraulic control reversing valve, and the oil return line of the locking cylinder is not connected to the oil tank. The gate is in the fully open position and the unit water inlet ball valve is in the open state. Even if the electromagnets of the ball-type reversing valve a and the ball-type reversing valve b lose power, the gate will not close, preventing the malfunction of automatically closing the gate due to power failure.
Claims
1. A hydraulic system for pumped storage tailgate capable of automatically closing the door without electricity, characterized in that: include: Hydraulic cylinder, used to drive the tailwater gate to open or close; A locking cylinder, wherein when the piston inside the locking cylinder is located at the left end of the cylinder body, the locking cylinder can lock the piston rod of the hydraulic cylinder in the fully open position of the tailwater gate; A hydraulic reversing valve is connected to the hydraulic oil return pipeline of the locking cylinder, and its hydraulic control port is connected to the unit water inlet valve, which can disconnect the hydraulic oil return pipeline of the locking cylinder from the oil tank when the unit water inlet valve is opened, and connect the hydraulic oil return pipeline of the locking cylinder to the oil tank when the unit water inlet valve is closed; The reversing valve group is connected to the hydraulic pipeline of the locking cylinder. When the reversing valve group is energized and the hydraulic reversing valve is connected, the piston in the locking cylinder can move toward the left end of the locking cylinder through the hydraulic pipeline. When the reversing valve group is de-energized and the hydraulic reversing valve is connected, the piston in the locking cylinder can move toward the right end through the hydraulic pipeline.
2. The hydraulic system for pumped storage tailgate capable of automatic door closing without electricity according to claim 1, characterized in that: Also includes: A two-way cartridge valve is connected to the hydraulic pipeline of the hydraulic cylinder, and its control oil port is connected to the control pipeline, and the control pipeline is connected to the roller reversing valve. When the roller reversing valve is disconnected, the two-way cartridge valve is closed, and when the roller reversing valve is connected, the two-way cartridge valve is opened; The roller of the roller reversing valve is driven by the locking cylinder. When the piston of the locking cylinder is at the left end, the locking cylinder has no thrust on the roller, and the roller reversing valve is disconnected; when the piston of the locking cylinder is at the right end, the locking cylinder has thrust on the roller, and the roller reversing valve is connected.
3. The hydraulic system for pumped storage tailgate capable of automatic door closing without electricity according to claim 2 is characterized in that: A pressure plate is mounted on the piston rod of the locking cylinder, and the pressure plate is arranged corresponding to the roller of the roller reversing valve.
4. The hydraulic system for pumped storage tailgate capable of automatic door closing without electricity according to claim 2 or 3, characterized in that: The control pipeline comprises a first pipeline and a second pipeline, wherein one end of the first pipeline is connected to the rod chamber of the hydraulic cylinder, and the other end is connected to the control oil port of the two-way cartridge valve; One end of the second pipeline is connected to the first pipeline, and the other end is connected to the oil tank. The roller reversing valve is installed on the second pipeline.
5. The hydraulic system for pumped storage tailgate capable of automatic door closing without electricity according to claim 1, characterized in that: Also includes: The gate position monitoring module is used to collect the position information of the tailwater gate and is connected to the control module circuit of the unit water inlet valve.
6. The hydraulic system for pumped storage tailgate capable of automatic door closing without electricity according to claim 5, characterized in that: The gate position monitoring module is connected to the control module circuit of the reversing valve group.
7. The hydraulic system for pumped storage tailgate capable of automatic door closing without electricity according to claim 5 or 6, characterized in that: The gate position monitoring module includes a position switch SQ1 corresponding to the fully open position of the tailwater gate, a position switch SQ2 located a certain distance below the position switch SQ1, and a position switch SQ3 located a certain distance below the position switch SQ2.
8. The hydraulic system for pumped storage tailgate capable of automatic door closing without electricity according to claim 7 is characterized in that: The position switch SQ2 includes a position switch SQ2.1 and a position switch SQ2.2 located before and after the tailwater gate, and the position switch SQ3 includes a position switch SQ3.1 and a position switch SQ3.2 located before and after the tailwater gate; The two signals of the position switches SQ2.1 and SQ2.2 are first connected in parallel, and the two signals of the position switches SQ3.1 and SQ3.2 are also first connected in parallel. The two parallel signals of the position switches SQ2 and SQ3 are then used in series.
9. The hydraulic system for pumped storage tailgate capable of automatic door closing without electricity according to claim 5 or 6, characterized in that: The reversing valve group includes two ball reversing valves a and two ball reversing valves b. The oil circuits of the two ball reversing valves a are connected in series when the electromagnet is powered off. The oil circuits of the two ball reversing valves b are also connected in series when the electromagnet is powered off. When the gate is in a fully open state and the unit water inlet valve is in the process of opening, and the tailwater accident gate and the unit water inlet valve have not yet formed a mechanical lock, as long as the four ball reversing valves do not lose power accidentally at the same time, the gate will not be mistakenly closed, thereby avoiding accidents; wherein the ball reversing valve a is connected to the rod chamber of the hydraulic cylinder through the third pipeline, connected to the oil tank through the fourth pipeline, and connected to the right chamber of the locking cylinder through the fifth pipeline; The ball-type reversing valve b is connected to the rod chamber of the hydraulic cylinder via the third pipeline, connected to the oil tank via the fourth pipeline, and connected to the left chamber of the locking cylinder via the sixth pipeline.