DEH system emergency shutdown control mechanism

Abstract

The emergency shut-off control mechanism of the DEH system is used to make the regulating valve oil motor respond to the connection between the overspeed protection control oil circuit and the pressureless return oil circuit to operate to close the regulating steam valve and / or make the main steam valve oil motor respond to the connection between the automatic shutdown emergency shut-off oil circuit and the pressureless return oil circuit to operate to close the main steam valve; it includes a hydraulic reversing valve and a sequence valve, the oil inlet and oil return port of the hydraulic reversing valve are connected to the pressure oil circuit and the pressureless return oil circuit respectively, and the oil outlet of the hydraulic reversing valve can be connected to the automatic shutdown emergency shut-off oil circuit and / or the overspeed protection control oil circuit; when the oil pressure of the pressure oil circuit is lower than the opening pressure of the sequence valve, the oil outlet and oil return port of the hydraulic reversing valve are connected, so that the automatic shutdown emergency shut-off oil circuit and / or the overspeed protection control oil circuit are connected to the pressureless return oil circuit. The DEH system emergency trip control mechanism involved in the present invention can respond to emergency trip in time in the case of power failure and mechanical overspeed protection failure, has good safety, and can realize self-control of emergency trip.

Description

Technical Field

[0001] The invention relates to the technical field of steam turbines, and in particular to an emergency shutoff control mechanism for a DEH system. Background Art

[0002] DEH system (Digital Electric Hydraulic Control System) is the abbreviation of digital electro-hydraulic control system of steam turbine. It is a professional control method for steam turbine generator. It is the only means to control the start, shutdown, speed control and power control of steam turbine. It is an indispensable control equipment for power plant to realize the coordinated control of units and remote automatic dispatching. DEH system consists of two parts: computer control part (DEH control system) and hydraulic actuator (EH system). Among them, DEH control system is the command center of DEH system, and EH system is the execution system of DEH system.

[0003] The EH system includes an oil supply system, an actuator and an emergency shut-off system. The function of the oil supply system is to provide high-pressure fire-resistant oil and drive the servo actuator. The actuator responds to the electrical command signal sent from the DEH control system to adjust the opening of each steam valve of the steam turbine. The emergency shut-off system is used to prevent major damage accidents to the unit caused by malfunction of some equipment during the operation of the steam turbine. When the steam turbine is in an emergency shut-off condition (such as the speed reaches 110% of the rated speed, the EH oil pressure is low, the lubricating oil pressure is low, the condenser vacuum is low, the thrust bearing is worn, etc.), the emergency shut-off system needs to respond quickly to close all the steam turbine inlet valves or only close the speed regulating valve, so as to achieve operation protection of the steam turbine.

[0004] The reliability of the emergency shutdown system directly affects the reliability of unit protection. At present, the emergency shutdown system is mainly divided into two situations: one is that during the operation of the unit, in order to prevent the malfunction of some equipment from causing serious damage to the unit, an automatic shutdown emergency shutdown system (AST) is installed. When an abnormal situation occurs, all steam inlet valves are closed and the unit is shut down immediately; the other is the overspeed protection control system (OPC), which temporarily closes the high-pressure regulating valve and the reheat regulating valve to reduce the turbine air intake and power, but cannot shut down the turbine. Therefore, the unit is equipped with an automatic shutdown emergency shutdown oil circuit (AST oil circuit) and an overspeed protection control oil circuit (OPC oil circuit). Among them, the automatic shutdown emergency trip system can be divided into two levels. The first is that the tripping electrical signal of the emergency trip control device (ETS for short) can activate the automatic shutdown emergency trip solenoid valve (AST solenoid valve for short), so that the AST oil circuit can be drained, all steam inlet valves can be closed, and the unit can be shut down; the second is the mechanical overspeed and manual shutdown part. When it is activated, the diaphragm valve can be used to unload the AST oil circuit, all steam inlet valves can be closed, and the unit can be shut down, which plays a role in emergency protection.

[0005] The actuator in the EH system is an oil motor, which mainly includes a control block and a hydraulic cylinder. According to the type of steam valve to be adjusted, the oil motor is mainly divided into the main steam valve, high-pressure regulating valve, medium-pressure main steam valve, and medium-pressure regulating valve oil motor. According to the different control blocks, the oil motor can be divided into two types: switch type and control type. Among them, the high-pressure regulating valve oil motor and the medium-pressure regulating valve oil motor are both control type. The control type oil motor uses the servo valve in the control block to make the regulating valve stay at any position; the high-pressure main steam valve oil motor and the medium-pressure main steam valve oil motor are both switch type. The switch type oil motor uses the solenoid valve in the control block to realize the full opening or closing of the main steam valve. In addition to being able to control the piston action of the hydraulic cylinder to adjust the opening of each steam valve of the steam turbine through the control block responding to the electrical signal of the DEH control system, it can also control the lifting of the piston in the hydraulic cylinder of the oil motor by draining the hydraulic oil in the AST oil circuit or OPC oil circuit through the emergency trip system, thereby directly or indirectly driving the valve stem to close the main steam valve and regulating valve to achieve emergency protection of the steam turbine.

[0006] Due to the internal leakage of the hydraulic transmission system, the EH system inevitably has pressure loss. When the EH oil pressure is too low, it will affect the pushing effect on the piston in the hydraulic cylinder, which may easily cause the steam valve to fail to close. Therefore, when the pressure switch on the pressure oil circuit detects the oil pressure of the EH system, the pressure switch sends a signal to the DEH control system, so that the DEH control system controls the AST solenoid valve to be energized, causing the AST oil circuit to unload oil, thereby closing all steam inlet valves and shutting down the unit. The emergency tripping mode of this emergency trip control device, as well as the above-mentioned manual shutdown and overspeed protection control systems, all require power supply to operate. Once a power outage occurs due to weather reasons such as lightning and the mechanical overspeed protection is stuck, if the emergency tripping system does not respond in time, it will cause the turbine to overspeed, causing huge losses to the company. Summary of the invention

[0007] The first technical problem to be solved by the present invention is to provide a DEH system emergency trip control mechanism in response to the above-mentioned technical status quo, which can respond promptly in the event of power outage and mechanical overspeed protection failure, thereby improving the safety of the steam turbine unit.

[0008] The second technical problem to be solved by the present invention is to provide a DEH system emergency shutoff control mechanism in response to the above-mentioned technical status quo, which can realize self-control of emergency shutoff without manual intervention and sensor feedback, making control signal transmission more reliable and less prone to errors in operation.

[0009] The third technical problem to be solved by the present invention is to provide a DEH system emergency shut-off control mechanism in response to the above-mentioned technical status quo, which can delay the impact of the hydraulic oil when the reversing valve is switched inside, so as to make the hydraulic system run more stably.

[0010] The technical solution adopted by the present invention to solve the above technical problems is: a DEH system emergency shutoff control mechanism is used to make the regulating valve oil motor respond to the conduction between the overspeed protection control oil circuit and the pressureless oil return oil circuit to operate to close the regulating valve and / or make the main steam valve oil motor respond to the conduction between the automatic shutdown emergency shutoff oil circuit and the pressureless oil return oil circuit to operate to close the main steam valve;

[0011] It is characterized in that: it comprises a hydraulic reversing valve and a sequence valve, the hydraulic reversing valve has an oil inlet, an oil outlet, an oil return port and a control port, the oil inlet of the hydraulic reversing valve is communicated with the pressure oil circuit, the oil outlet of the hydraulic reversing valve can be communicated with the automatic shutdown emergency trip oil circuit and / or the overspeed protection control oil circuit, and the oil return port of the hydraulic reversing valve is communicated with the pressureless oil return oil circuit;

[0012] The sequence valve has an oil inlet and an oil outlet, the oil inlet of the sequence valve is connected to the pressure oil circuit, one of the control ports of the hydraulic reversing valve is connected to the oil outlet of the sequence valve, and the other is connected to the pressureless oil return oil circuit;

[0013] When the pressure of the pressure oil circuit reaches the opening pressure of the sequence valve, the oil inlet and oil outlet of the hydraulic reversing valve are connected, so that the automatic shutdown emergency shut-off oil circuit and the overspeed protection control oil circuit are blocked from the pressureless return oil circuit. When the pressure of the pressure oil circuit is lower than the opening pressure of the sequence valve, the oil outlet and oil return port of the hydraulic reversing valve are connected, so that the automatic shutdown emergency shut-off oil circuit and / or the overspeed protection control oil circuit are connected to the pressureless return oil circuit.

[0014] In order to allow the hydraulic oil in the automatic shutdown emergency trip oil circuit and / or the overspeed protection control oil circuit to be quickly discharged during emergency trip, a cartridge valve is provided between the oil outlet of the hydraulic reversing valve and the automatic shutdown emergency trip oil circuit and / or the overspeed protection control oil circuit, the cartridge valve having a control port, a first working oil port and a second working oil port, the control port of the cartridge valve being able to communicate with the oil outlet of the hydraulic reversing valve, the first working oil port of the cartridge valve being connected to the automatic shutdown emergency trip oil circuit or the overspeed protection control oil circuit, and the second working port of the cartridge valve being connected to the pressure-free return oil circuit.

[0015] The further design also includes an automatic shutdown pressure oil circuit, a first throttling orifice plate and a second throttling orifice plate, one end of the automatic shutdown pressure oil circuit is connected to the automatic shutdown emergency shut-off oil circuit through the first throttling orifice plate, and the other end of the automatic shutdown pressure oil circuit is connected to the pressure-free return oil circuit through the second throttling orifice plate; the cartridge valve includes a first cartridge valve, a second cartridge valve, a third cartridge valve and a fourth cartridge valve, and the control ports of the first cartridge valve, the second cartridge valve, the third cartridge valve and the fourth cartridge valve can all be connected to the liquid The oil outlet of the movable reversing valve is connected, the first working ports of the first cartridge valve and the third cartridge valve are both connected to the automatic shutdown emergency shutoff oil circuit, the first working ports of the second cartridge valve and the fourth cartridge valve are both connected to the automatic shutdown emergency shutoff oil circuit through the automatic shutdown pressure oil circuit, the second working ports of the first cartridge valve and the third cartridge valve are both connected to the pressureless return oil circuit through the automatic shutdown pressure oil circuit, and the second working ports of the second cartridge valve and the fourth cartridge valve are both connected to the pressureless return oil circuit. By arranging the first cartridge valve, the second cartridge valve, the third cartridge valve and the fourth cartridge valve in series and parallel, the first cartridge valve and the third cartridge valve are a group, the second cartridge valve and the fourth cartridge valve are a group, and the automatic shutdown emergency shutoff oil circuit can only be connected to the pressureless return oil circuit when the control port oil pressure of at least one cartridge valve in the two groups is 0, and the automatic shutdown pressure oil circuit is set, so that the safety of the shutoff system is higher.

[0016] In a further design, the cartridge valve includes a fifth cartridge valve and a sixth cartridge valve arranged in parallel, and the control ports of the fifth cartridge valve and the sixth cartridge valve can be connected to the oil outlet of the hydraulic reversing valve, the first working ports of the fifth cartridge valve and the sixth cartridge valve are connected to the overspeed protection control oil circuit, and the second working ports of the fifth cartridge valve and the sixth cartridge valve are connected to the pressureless return oil circuit. By setting the fifth cartridge valve and the sixth cartridge valve in parallel, when the oil pressure of the control port of at least one of the fifth cartridge valve and the sixth cartridge valve is 0, the overspeed protection control oil circuit can be connected to the pressureless return oil circuit, so that the safety of the shutoff system is higher.

[0017] According to a further design, a solenoid valve is provided between the oil outlet of the hydraulic reversing valve and the control port of the cartridge valve, and the solenoid valve is used to control whether the control port of the cartridge valve is connected to the oil outlet of the hydraulic reversing valve.

[0018] In a further design, a solenoid valve is provided between the oil outlet of the hydraulic reversing valve and the overspeed protection control oil circuit, and the solenoid valve is used to control whether the overspeed protection control oil circuit is connected to the oil outlet of the hydraulic reversing valve.

[0019] The above-mentioned solenoid valve needs to have the function of on and off, so a two-position two-way reversing valve can be used, or a two-position three-way reversing valve commonly used in the DEH system can be used.

[0020] In order to further improve the safety of the emergency trip system, the number of the electromagnetic valves is at least two, and at least two electromagnetic valves are arranged in series or in parallel. The on-off rules of each electromagnetic valve can be the same or different.

[0021] It is further designed that a first damper for controlling the reset time of the hydraulic reversing valve is provided between the control port of the hydraulic reversing valve and the pressure-free oil return circuit.

[0022] According to a further design, a second damper is provided between the pressure oil circuit and the oil inlet of the hydraulic reversing valve.

[0023] The provision of the first damper and the second damper can protect the hydraulic reversing valve and the control circuit.

[0024] In order to ensure that the main steam valve is not affected when the regulating valve is closed, two one-way valves are provided between the automatic shutdown emergency shut-off oil circuit and the overspeed protection control oil circuit. The two one-way valves are arranged in parallel, and the inlets of the two one-way valves are connected to the overspeed protection control oil circuit, and the outlets of the two one-way valves are connected to the automatic shutdown emergency shut-off oil circuit, so that the overspeed protection control oil circuit can be connected to the pressure-free return oil circuit through the automatic shutdown emergency shut-off oil circuit.

[0025] Compared with the prior art, the advantages of the present invention are: through the combined use of a sequence valve and a hydraulic reversing valve to control the automatic shutdown emergency trip oil circuit and / or the overspeed protection control oil circuit and the pressure-free return oil circuit, not only can the emergency trip of the DEH system respond in time in the event of a power outage and failure of the mechanical overspeed protection, thereby improving the safety of the steam turbine unit, but also, compared with the automatic shutdown emergency trip system and overspeed protection control system that need to be used in conjunction with an external controller, the emergency trip of the DEH system does not require manual intervention and sensor feedback, and can achieve self-control of the emergency trip, making the control signal transmission more reliable and the operation less prone to errors. It can also delay the impact of the hydraulic oil when it is reversed inside the reversing valve, making the hydraulic system operation more stable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a connection principle diagram of the emergency trip control mechanism of the DEH system in Example 1 of the present invention;

[0027] Figure 2 This is a connection schematic diagram of the emergency shutdown control mechanism of the DEH system in Example 4 of the present invention. DETAILED DESCRIPTION

[0028] The present invention is further described in detail below with reference to the accompanying drawings.

[0029] Example 1

[0030] like Figure 1 FIG. 1 is a first preferred embodiment of the present invention.

[0031] like Figure 1 As shown, the emergency shut-off control mechanism of the DEH system in this embodiment is used to make the regulating valve oil motor 92 respond to the conduction between the overspeed protection control oil circuit 14 and the pressureless return oil circuit 12 to operate to close the regulating steam valve 102 and to make the main steam valve oil motor 91 respond to the conduction between the automatic shutdown emergency shut-off oil circuit 13 and the pressureless return oil circuit 12 to operate to close the main steam valve 101.

[0032] like Figure 1 As shown, two one-way valves 4 are provided between the automatic shutdown emergency shut-off oil circuit 13 and the overspeed protection control oil circuit 14, and the two one-way valves 4 are arranged in parallel, and the inlets of the two one-way valves 4 are connected to the overspeed protection control oil circuit 14, and the outlets of the two one-way valves 4 are connected to the automatic shutdown emergency shut-off oil circuit 13, so that the overspeed protection control oil circuit 14 can be connected to the pressure-free return oil circuit 12 through the automatic shutdown emergency shut-off oil circuit 13, that is, the automatic shutdown emergency shut-off oil circuit 13 is connected to the pressure-free return oil circuit 12 to control the operation of the main steam valve oil motor 91 and the regulating valve oil motor 92.

[0033] like Figure 1 As shown, the emergency shutoff control mechanism of the DEH system in this embodiment includes a hydraulic reversing valve 2 and a sequence valve 3. The hydraulic reversing valve 2 has an oil inlet, an oil outlet, an oil return port and a control port. The oil inlet of the hydraulic reversing valve 2 is connected to the pressure oil circuit 11. The oil outlet of the hydraulic reversing valve 2 can be connected to the automatic shutdown emergency shutoff oil circuit 13 in one way, and can be connected to the overspeed protection control oil circuit 14 in another way. The oil return port of the hydraulic reversing valve 2 is connected to the pressureless return oil circuit 12. The sequence valve 3 has an oil inlet and an oil outlet. The oil inlet of the sequence valve 3 is connected to the pressure oil circuit 11. The control port of the hydraulic reversing valve 2 is connected to the oil outlet of the sequence valve 3 in one way, and is connected to the pressureless return oil circuit 12 in another way. When the pressure of the pressure oil circuit 11 reaches the opening pressure of the sequence valve 3, the oil inlet and oil outlet of the hydraulic reversing valve 2 are connected, so that the automatic shutdown emergency shut-off oil circuit 13 and the overspeed protection control oil circuit 14 are both blocked from the pressureless return oil circuit 12; when the pressure of the pressure oil circuit 11 is lower than the opening pressure of the sequence valve 2, the oil outlet and oil return port of the hydraulic reversing valve 2 are connected, so that the automatic shutdown emergency shut-off oil circuit 13 and the overspeed protection control oil circuit 14 can be connected to the pressureless return oil circuit 12.

[0034] In this embodiment, the automatic shutdown emergency trip oil circuit 13 and the overspeed protection control oil circuit 14 are controlled to be connected to the pressure-free return oil circuit 12 through the combined use of the sequence valve 3 and the hydraulic reversing valve 2. This not only enables the emergency trip of the DEH system to respond promptly in the event of a power outage or failure of the mechanical overspeed protection, thereby improving the safety of the steam turbine unit, but also, compared to the automatic shutdown emergency trip system and overspeed protection control system that need to be used in conjunction with an external controller, the emergency trip of the DEH system does not require manual intervention and sensor feedback, and can achieve self-control of the emergency trip, making the control signal transmission more reliable and the operation less prone to errors. It can also delay the impact of the hydraulic oil when it is reversed inside the reversing valve, making the operation of the hydraulic system more stable.

[0035] like Figure 1 As shown, in order to quickly drain the hydraulic oil in the automatic shutdown emergency shutoff oil circuit 13 and the overspeed protection control oil circuit 14 during emergency shutoff, cartridge valves are respectively provided between the oil outlet of the hydraulic reversing valve 2 and the automatic shutdown emergency shutoff oil circuit 13 and between the oil outlet of the hydraulic reversing valve 2 and the overspeed protection control oil circuit 14. The cartridge valve has a control port, a first working oil port and a second working oil port. In order to make the emergency shutoff system of the DEH system safer, a solenoid valve is provided between the oil outlet of the hydraulic reversing valve 2 and the control port of the cartridge valve. The solenoid valve is used to control whether the control port of the cartridge valve is connected to the oil outlet of the hydraulic reversing valve 2.

[0036] Specifically, the emergency shutoff control mechanism of the DEH system in this embodiment further includes an automatic shutdown pressure oil circuit 15, a first throttling orifice plate 51 and a second throttling orifice plate 52, and one end of the automatic shutdown pressure oil circuit 15 is connected to the automatic shutdown emergency shutoff oil circuit 13 through the first throttling orifice plate 51, and the other end of the automatic shutdown pressure oil circuit 15 is connected to the pressure-free return oil circuit 12 through the second throttling orifice plate 52. The solenoid valve includes a first solenoid valve 61, a second solenoid valve 62, a third solenoid valve 63 and a fourth solenoid valve 64 arranged in parallel, and the oil inlets of the first solenoid valve 61, the second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64 are all connected to the oil outlet of the hydraulic reversing valve 2. The cartridge valve includes a first cartridge valve 71, a second cartridge valve 72, a third cartridge valve 73 and a fourth cartridge valve 74. The control ports of the first cartridge valve 71, the second cartridge valve 72, the third cartridge valve 73 and the fourth cartridge valve 74 are connected to the oil outlets of the first solenoid valve 61, the second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64 respectively, the first working ports of the first cartridge valve 71 and the third cartridge valve 73 are both connected to the automatic shutdown emergency shut-off oil circuit 13, the first working ports of the second cartridge valve 72 and the fourth cartridge valve 74 are both connected to the automatic shutdown emergency shut-off oil circuit 13 through the automatic shutdown pressure oil circuit 15, the second working ports of the first cartridge valve 71 and the third cartridge valve 73 are both connected to the no-pressure return oil circuit 12 through the automatic shutdown pressure oil circuit 15, and the second working ports of the second cartridge valve 72 and the fourth cartridge valve 74 are both connected to the no-pressure return oil circuit 12.

[0037] In this embodiment, the first cartridge valve 71, the second cartridge valve 72, the third cartridge valve 73 and the fourth cartridge valve 74 are arranged in series and parallel, so that the first cartridge valve 71 and the third cartridge valve 73 are a group, and the second cartridge valve 72 and the fourth cartridge valve 74 are a group. Only when the control port oil pressure of at least one cartridge valve in the two groups is 0, the automatic shutdown emergency shut-off oil circuit 13 and the pressure-free return oil circuit 12 can be connected, and the automatic shutdown pressure oil circuit 15 and the first solenoid valve 61, the second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64 are arranged to make the shut-off system safer.

[0038] like Figure 1As shown, the solenoid valve also includes a fifth solenoid valve 65 and a sixth solenoid valve 66 arranged in parallel, and the oil inlets of the fifth solenoid valve 65 and the sixth solenoid valve 66 are both connected to the oil outlet of the hydraulic reversing valve 2. The cartridge valve also includes a fifth cartridge valve 75 and a sixth cartridge valve 76 arranged in parallel, and the control ports of the fifth cartridge valve 75 and the sixth cartridge valve 76 are respectively connected to the oil outlets of the fifth solenoid valve 65 and the sixth solenoid valve 66, the first working ports of the fifth cartridge valve 75 and the sixth cartridge valve 76 are both connected to the overspeed protection control oil circuit 14, and the second working ports of the fifth cartridge valve 75 and the sixth cartridge valve 76 are both connected to the pressure-free return oil circuit 12. By arranging the fifth cartridge valve 75 and the sixth cartridge valve 76 and the fifth solenoid valve 65 and the sixth solenoid valve 66 in parallel, when the oil pressure at the control port of at least one of the fifth cartridge valve 75 and the sixth cartridge valve 76 is 0, the overspeed protection control oil circuit 14 can be connected with the pressure-free return oil circuit 12, thereby making the shut-off system safer.

[0039] like Figure 1 As shown, the solenoid valve in this embodiment is a two-position three-way reversing valve, and the solenoid valve has an oil inlet, an oil outlet and an oil return port. Specifically, in the energized state, the oil inlet and oil outlet of the first solenoid valve 61, the second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64 are connected; in the de-energized state of the first solenoid valve 61, the second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64, the oil inlet and oil return port of the first solenoid valve 61, the second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64 are connected. When the fifth solenoid valve 65 and the sixth solenoid valve 66 are de-energized, the oil inlet and oil outlet of the fifth solenoid valve 65 and the sixth solenoid valve 66 are connected; when the fifth solenoid valve 65 and the sixth solenoid valve 66 are energized, the oil inlet and oil return port of the fifth solenoid valve 65 and the sixth solenoid valve 66 are connected.

[0040] like Figure 1 As shown, in order to protect the hydraulic reversing valve and the control circuit, a first damper 81 for controlling the reset time of the hydraulic reversing valve 2 is provided between the control port of the hydraulic reversing valve 2 and the pressureless oil return oil circuit 12. A second damper 82 is provided between the oil inlet of the hydraulic reversing valve 2 and the pressure oil circuit 11.

[0041] like Figure 1 As shown, the working principle of the emergency trip control mechanism of the DEH system of this embodiment is:

[0042] Under normal working conditions, the oil pressure of the pressure oil circuit 11 is greater than the opening pressure of the sequence valve 3, so that the valve port of the sequence valve 3 is opened, and the hydraulic oil in the pressure oil circuit 11 enters the control port of the hydraulic reversing valve 2, so that the hydraulic reversing valve 2 is reversed, so that the oil inlet and oil outlet of the hydraulic reversing valve 2 are connected; at this time, the first solenoid valve 61, the second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64 are in the energized state, and the fifth solenoid valve 65 and the sixth solenoid valve 66 are in the de-energized state; the hydraulic oil flowing out of the oil outlet of the hydraulic reversing valve 2 respectively enters the first cartridge valve 71, the second solenoid valve 62, the third solenoid valve 63, the fourth solenoid valve 64, the fifth solenoid valve 65 and the sixth solenoid valve 66 through the first solenoid valve 61, the second solenoid valve 62, the third solenoid valve 63, the fourth solenoid valve 64, the fifth solenoid valve 65 and the sixth solenoid valve 66 respectively. The control ports of the second cartridge valve 72, the third cartridge valve 73, the fourth cartridge valve 74, the fifth cartridge valve 75 and the sixth cartridge valve 76 close the valve ports of the first cartridge valve 71, the second cartridge valve 72, the third cartridge valve 73, the fourth cartridge valve 74, the fifth cartridge valve 75 and the sixth cartridge valve 76, resulting in the automatic shutdown emergency trip oil circuit 13 and the overspeed protection control oil circuit 14 being blocked from the pressureless return oil circuit 12, and the turbine operating normally.

[0043] When the oil pressure in the pressure oil circuit 11 drops to a value lower than the opening pressure of the sequence valve 3, the valve port of the sequence valve 3 is closed, and the hydraulic oil in the control port of the hydraulic reversing valve 2 enters the pressure-free oil return channel 12 through the first damper 81, so that the hydraulic reversing valve 2 is reset, so that the oil outlet and the oil return port of the hydraulic reversing valve 2 are connected; at this time, the first solenoid valve 61, the second solenoid valve 62, the third solenoid valve 63 and the fourth solenoid valve 64 are still in the energized state, and the fifth solenoid valve 65 and the sixth solenoid valve 66 are still in the de-energized state; the control ports of the first cartridge valve 71, the second cartridge valve 72, the third cartridge valve 73, the fourth cartridge valve 74, the fifth cartridge valve 75 and the sixth cartridge valve 76 are no longer supplied with oil, so that the first cartridge valve 71, the second cartridge valve 72, the third cartridge valve 73, the fourth cartridge valve 74, the fifth cartridge valve 75 and the sixth cartridge valve 76 are closed. The valve ports of the third cartridge valve 73, the fourth cartridge valve 74, the fifth cartridge valve 75 and the sixth cartridge valve 76 are all opened, the automatic shutdown emergency shut-off oil circuit 13 is connected to the automatic shutdown pressure oil circuit 15 through the first cartridge valve 71 and the third cartridge valve 73, and the automatic shutdown pressure oil circuit 15 is connected to the non-pressure return oil circuit 12 through the second cartridge valve 72 and the fourth cartridge valve 74, so that the automatic shutdown emergency shut-off oil circuit 13 is connected to the non-pressure return oil circuit 12, and the overspeed protection control oil circuit 14 is connected to the non-pressure return oil circuit 12 through the fifth cartridge valve 75 and the sixth cartridge valve 76, so that the hydraulic oil in the automatic shutdown emergency shut-off oil circuit 13 and the overspeed protection control oil circuit 14 is drained, and the main steam valve and regulating valve of the steam turbine are closed.

[0044] Example 2

[0045] The difference between this embodiment and embodiment 1 is that the oil outlet of the hydraulic reversing valve 2 can only be connected to the automatic shutdown emergency shut-off oil circuit 13, so that the reversing of the hydraulic reversing valve 2 can only conduct the automatic shutdown emergency shut-off oil circuit 13 and the pressure-free return oil circuit 12, while the overspeed protection control oil circuit 14 is conducted to the pressure-free return oil circuit 12 through the automatic shutdown emergency shut-off oil circuit 13.

[0046] Example 3

[0047] The difference between this embodiment and embodiment 1 is that the oil outlet of the hydraulic reversing valve 2 can only be connected to the overspeed protection control oil circuit 14, so that the reversing of the hydraulic reversing valve 2 can only realize the conduction between the overspeed protection control oil circuit 14 and the pressure-free return oil circuit 12, so that the emergency shut-off control mechanism of the DEH system can only control the closing of the regulating valve.

[0048] Example 4

[0049] like Figure 2 FIG. 4 is a fourth preferred embodiment of the present invention.

[0050] like Figure 2 As shown, the difference between this embodiment and embodiment 3 is that only a solenoid valve is provided between the oil outlet of the hydraulic reversing valve 2 and the overspeed protection control oil circuit 14, and no cartridge valve is provided.

[0051] Specifically, a seventh solenoid valve 67 and an eighth solenoid valve 68 are provided between the oil outlet of the hydraulic reversing valve 2 and the overspeed protection control oil circuit 14. The seventh solenoid valve 67 and the eighth solenoid valve 68 are arranged in series. The seventh solenoid valve 67 and the eighth solenoid valve 68 both have an oil inlet, an oil outlet and an oil return port. The oil inlet of the seventh solenoid valve 67 is connected to the oil outlet of the hydraulic reversing valve 2, the oil outlet of the seventh solenoid valve 67 is connected to the oil inlet of the eighth solenoid valve 68, the oil outlet of the eighth solenoid valve 68 is connected to the overspeed protection control oil circuit 14, and the oil return ports of the seventh solenoid valve 67 and the eighth solenoid valve 68 are connected to the pressure-free return oil circuit 12.

Claims

1. A DEH system emergency shutoff control mechanism, used to cause a regulating valve oil motor (92) to respond to the conduction between an overspeed protection control oil circuit (14) and a pressureless oil return oil circuit (12) to operate to close a regulating valve (102) and / or cause a main steam valve oil motor (91) to respond to the conduction between an automatic shutdown emergency shutoff oil circuit (13) and the pressureless oil return oil circuit (12) to operate to close a main steam valve (101); Features: The invention comprises a hydraulic reversing valve (2) and a sequence valve (3), wherein the hydraulic reversing valve (2) has an oil inlet, an oil outlet, an oil return port and a control port, wherein the oil inlet of the hydraulic reversing valve (2) is connected to a pressure oil circuit (11), the oil outlet of the hydraulic reversing valve (2) can be connected to the automatic shutdown emergency trip oil circuit (13) and / or the overspeed protection control oil circuit (14), and the oil return port of the hydraulic reversing valve (2) is connected to the pressureless oil return oil circuit (12); The sequence valve (3) has an oil inlet and an oil outlet, the oil inlet of the sequence valve (3) is connected to the pressure oil circuit (11), one of the control ports of the hydraulic reversing valve (2) is connected to the oil outlet of the sequence valve (3), and the other is connected to the pressureless oil return circuit (12); When the pressure of the pressure oil circuit (11) reaches the opening pressure of the sequence valve (3), the oil inlet and the oil outlet of the hydraulic reversing valve (2) are connected, so that the automatic shutdown emergency shut-off oil circuit (13) and the overspeed protection control oil circuit (14) are both blocked from the pressureless return oil circuit (12); when the pressure of the pressure oil circuit (11) is lower than the opening pressure of the sequence valve (3), the oil outlet and the oil return port of the hydraulic reversing valve (2) are connected, so that the automatic shutdown emergency shut-off oil circuit (13) and / or the overspeed protection control oil circuit (14) are connected to the pressureless return oil circuit (12).

2. The DEH system emergency shutoff control mechanism according to claim 1, characterized in that: A cartridge valve is provided between the oil outlet of the hydraulic reversing valve (2) and the automatic shutdown emergency trip oil circuit (13) and / or the overspeed protection control oil circuit (14), the cartridge valve having a control port, a first working oil port and a second working oil port, the control port of the cartridge valve being able to communicate with the oil outlet of the hydraulic reversing valve (2), the first working oil port of the cartridge valve being connected to the automatic shutdown emergency trip oil circuit (13) or the overspeed protection control oil circuit (14), and the second working port of the cartridge valve being connected to the pressure-free return oil circuit (12).

3. The DEH system emergency shutoff control mechanism according to claim 2 is characterized in that: The invention also comprises an automatic shutdown pressure oil circuit (15), a first throttling orifice plate (51) and a second throttling orifice plate (52); one end of the automatic shutdown pressure oil circuit (15) is connected to the automatic shutdown emergency shutoff oil circuit (13) through the first throttling orifice plate (51), and the other end of the automatic shutdown pressure oil circuit (15) is connected to the pressure-free return oil circuit (12) through the second throttling orifice plate (52); the cartridge valve comprises a first cartridge valve (71), a second cartridge valve (72), a third cartridge valve (73) and a fourth cartridge valve (74), and the control ports of the first cartridge valve (71), the second cartridge valve (72), the third cartridge valve (73) and the fourth cartridge valve (74) can all be connected to the control ports of the cartridge valve (71), the second cartridge valve (72), the third cartridge valve (73) and the fourth cartridge valve (74). The oil outlet of the hydraulic reversing valve (2) is connected, the first working ports of the first cartridge valve (71) and the third cartridge valve (73) are both connected to the automatic shutdown emergency shut-off oil circuit (13), the first working ports of the second cartridge valve (72) and the fourth cartridge valve (74) are both connected to the automatic shutdown emergency shut-off oil circuit (13) through the automatic shutdown pressure oil circuit (15), the second working ports of the first cartridge valve (71) and the third cartridge valve (73) are both connected to the pressureless return oil circuit (12) through the automatic shutdown pressure oil circuit (15), and the second working ports of the second cartridge valve (72) and the fourth cartridge valve (74) are both connected to the pressureless return oil circuit (12).

4. The DEH system emergency shutoff control mechanism according to claim 2 or 3, characterized in that: The cartridge valve comprises a fifth cartridge valve (75) and a sixth cartridge valve (76) which are arranged in parallel, and the control ports of the fifth cartridge valve (75) and the sixth cartridge valve (76) are both able to communicate with the oil outlet of the hydraulic reversing valve (2), the first working ports of the fifth cartridge valve (75) and the sixth cartridge valve (76) are both communicated with the overspeed protection control oil circuit (14), and the second working ports of the fifth cartridge valve (75) and the sixth cartridge valve (76) are both communicated with the pressureless return oil circuit (12).

5. The DEH system emergency shutoff control mechanism according to claim 2, characterized in that: An electromagnetic valve is provided between the oil outlet of the hydraulic reversing valve (2) and the control port of the cartridge valve, and the electromagnetic valve is used to control whether the control port of the cartridge valve is connected to the oil outlet of the hydraulic reversing valve (2).

6. The DEH system emergency shutoff control mechanism according to claim 1, characterized in that: An electromagnetic valve is provided between the oil outlet of the hydraulic reversing valve (2) and the overspeed protection control oil circuit (14), and the electromagnetic valve is used to control whether the overspeed protection control oil circuit (14) and the oil outlet of the hydraulic reversing valve (2) are connected.

7. The DEH system emergency shutoff control mechanism according to claim 5 or 6, characterized in that: The number of the solenoid valves is at least two, and at least two solenoid valves are arranged in series or in parallel.

8. The DEH system emergency shutoff control mechanism according to any one of claims 1 to 3, characterized in that: A first damper (81) for controlling the reset time of the hydraulic reversing valve (2) is provided between the control port of the hydraulic reversing valve (2) and the pressure-free oil return oil circuit (12).

9. The DEH system emergency shutoff control mechanism according to any one of claims 1 to 3, characterized in that: A second damper (82) is provided between the pressure oil circuit (11) and the oil inlet of the hydraulic reversing valve (2).

10. The DEH system emergency shutoff control mechanism according to any one of claims 1 to 3, characterized in that: Two one-way valves (4) are provided between the automatic shutdown emergency trip oil circuit (13) and the overspeed protection control oil circuit (14). The two one-way valves (4) are arranged in parallel, and the inlets of the two one-way valves (4) are both connected to the overspeed protection control oil circuit (14), and the outlets of the two one-way valves (4) are both connected to the automatic shutdown emergency trip oil circuit (13), so that the overspeed protection control oil circuit (14) can be connected to the pressureless return oil circuit (12) through the automatic shutdown emergency trip oil circuit (13).

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