Safety control device for regulating valve

Abstract

The utility model discloses a safety control device of a regulating valve, which comprises a servo control oil way, an interruption oil way, a hydraulic servo-motor, a pressure oil way, a safety oil way and an oil discharge channel, and the pressure oil way is respectively connected with a rod cavity and a rodless cavity of the hydraulic servo-motor. Each servo control oil way comprises a servo valve, an electromagnetic valve I, a hydraulic control one-way valve I, a hydraulic control one-way valve II and a pressure switch, an oil inlet of the servo valve is communicated with the pressure oil way, a control oil port of the servo valve is sequentially connected with the hydraulic control one-way valve I and the hydraulic control one-way valve II, and the hydraulic control one-way valve II is connected with a rodless cavity of the hydraulic servo-motor; an oil outlet of the electromagnetic valve I is respectively connected with the hydraulic control one-way valve I, the hydraulic control one-way valve II and the pressure switch; and the cutoff oil way is connected with the safety oil way, the pressure oil way and an oil inlet of the electromagnetic valve I respectively. The flow characteristic of the servo valve can be completely released, the adjusting performance of the valve is guaranteed, the valve can be controlled to be rapidly closed during emergency interruption, and the safety of a unit is guaranteed.

Description

TECHNICAL FIELD

[0001] The utility model relates to steam turbine governing valve control technical field, concretely relates to a kind of governing valve safety control device. BACKGROUND

[0002] In the field of hydraulic control of steam turbine valve oil motor in thermal power plant, double-path servo valve control loop is usually used to control oil motor, such as the patent document with publication number CN217813614U discloses a kind of steam turbine valve oil motor redundancy servo valve hydraulic control loop, the oil inlet oil way is connected with servo valve I, servo valve II and quick closing electromagnetic valve respectively, servo valve I is connected with electromagnetic valve I, servo valve II is connected with electromagnetic valve II, quick closing electromagnetic valve is connected with cartridge valve I, cartridge valve II is connected with high-pressure oil pipeline, electromagnetic valve I, electromagnetic valve II, cartridge valve I and cartridge valve II are connected with the working chamber and non-working chamber of oil motor cylinder respectively;The oil return pipeline of cartridge valve I and cartridge valve II is connected with the oil return chamber of oil motor, the oil return chamber is connected with total oil return pipeline, the oil return pipeline of servo valve I and servo valve II is connected on total oil return pipeline.This control loop works simultaneously by two oil ways receiving control instruction, and by selecting one to be used and one to be standby through two electromagnetic valves, any side oil way or electrical element failure can be repaired online.But through careful analysis, it is found that the prior art still has the following technical problems:

[0003] 1, the prior art uses steel ball electromagnetic valve directly connected to the control loop of oil motor oil cavity, although steel ball valve has good sealing characteristics, but the flow of steel ball electromagnetic valve 30L / min is less than the flow of servo valve 63L / min, which makes the flow characteristics of servo valve cannot be fully released, affecting the valve regulating performance.When the unit appears blocking signal, the safety oil pressure decreases, and the safety oil way cannot isolate the control oil way through hydraulic interlocking.

[0004] 2, the prior art cannot distinguish which servo valve is working, and cannot judge whether the electromagnetic valve is switched successfully after switching.

[0005] 3, the safety oil way of the prior art is not related to the control oil way, when the unit needs to be blocked due to failure, servo valve will still be filled with oil, which may cause the control loop to move the valve to the open direction during emergency blocking, thereby slowing down the valve closing speed and affecting the unit safety.

[0006] 4, the valve closing oil motor output of the prior art is too large, the valve stem and moving parts of steam valve have a large force, which causes high stress level and easy damage.

[0007] In addition, ordinary electromagnetic valves are also used in the prior art, but the internal leakage of ordinary electromagnetic valves is ≥500ml / min, which cannot effectively isolate the servo valve control loop, and the valve position cannot be stable in steady state. Utility Model Content

[0008] To overcome the aforementioned problems in the prior art, this invention provides a safety control device for a regulating valve. This invention employs a servo valve configured with two hydraulically controlled check valves, using a small flow of safety oil as the pilot oil for the hydraulically controlled check valves. The safety oil is controlled by a solenoid valve to achieve a control structure that controls the opening and closing of the hydraulically controlled check valves. This structure not only allows the flow characteristics of the servo valve to be fully released, ensuring the regulating performance of the valve, but also controls the valve to close quickly in case of emergency shutdown, thereby ensuring the safety of the unit.

[0009] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0010] A safety control device for a regulating valve includes a servo control oil circuit, a shut-off oil circuit, a hydraulic actuator, a pressure oil passage, a safety oil passage, and a drain channel. The pressure oil passage is connected to the rod-side and rodless-side chambers of the hydraulic actuator, respectively. The servo control oil circuits are redundantly connected in parallel between the pressure oil passages and the rodless-side chamber of the hydraulic actuator. Each servo control oil circuit includes a servo valve, a solenoid valve I, a hydraulically controlled check valve I, a hydraulically controlled check valve II, and a pressure switch. The inlet of the servo valve is connected to the pressure oil passage, and the control port of the servo valve is sequentially connected to the hydraulically controlled check valve II. The system includes a directional valve I and a hydraulically controlled check valve II, with the unidirectional flow directions of the hydraulically controlled check valve I and the hydraulically controlled check valve II being opposite. The hydraulically controlled check valve II is connected to the rodless chamber of the hydraulic actuator. The oil outlet of the solenoid valve I is connected to the hydraulically controlled check valve I, the hydraulically controlled check valve II, and the pressure switch, respectively. The safety oil passage is connected to the pressure oil passage through a throttle orifice. The shut-off oil passage is connected to the safety oil passage, the pressure oil passage, and the oil inlet of the solenoid valve I, respectively. The oil outlet of the servo valve, the oil outlet of the solenoid valve I, and the oil outlet of the shut-off oil passage are all connected to the oil outlet channel.

[0011] The shut-off oil circuit includes a cartridge valve and two redundant solenoid valves II. The inlet of solenoid valve II is connected to the safety oil passage, and the outlet of solenoid valve II is connected to the control chamber of the cartridge valve and the inlet of solenoid valve I, respectively. The outlet of solenoid valve II is connected to the drain channel. The inlet of the cartridge valve is connected to the pressure oil passage, and the outlet of the cartridge valve is connected to the rodless chamber of the hydraulic actuator.

[0012] The servo valve is equipped with a throttling adjustment valve I at the front end of the oil inlet.

[0013] A throttling adjustment valve II is provided at the rear end of the hydraulic control check valve II.

[0014] The pressure oil passage is equipped with a dual oil filter. After being filtered by the dual oil filter, the pressure oil enters the servo control oil circuit, the shut-off oil circuit, and the hydraulic motor.

[0015] The rear end cover of the hydraulic cylinder of the hydraulic actuator is hinged to the bracket, and a return spring is installed on the piston rod of the hydraulic actuator, which is also hinged to a lever mechanism for opening and closing the regulating valve.

[0016] Both solenoid valve I and solenoid valve II are two-position three-way single-coil solenoid valves.

[0017] The advantages of using this utility model are:

[0018] 1. This utility model employs two servo control oil circuits and one shut-off oil circuit. Each servo control oil circuit includes one servo valve, one solenoid valve, and two pilot-operated check valves. The two pilot-operated check valves are connected to the outlet end of the servo valve, and the solenoid valve is connected to the control port of the pilot-operated check valve via safety oil. This structure utilizes the control mechanism of the solenoid valve controlling the opening and closing of the pilot-operated check valve via safety oil to achieve the control of the hydraulic actuator. Since the flow rate of the pilot-operated check valve is 120L / min, which is greater than the flow rate of the servo valve (63L / min), the flow characteristics of the servo valve can be fully released, ensuring a faster response during valve adjustment. Furthermore, the solenoid valve only participates in the control of the pilot-operated check valve. On the one hand, a SIL3 safety-certified solenoid valve with low internal leakage can be used; on the other hand, even if an ordinary solenoid valve is used, it will not affect the control of the pilot-operated check valve or the stable control of the hydraulic actuator. In addition, this utility model controls the opening of the hydraulic check valve through a safety oil circuit. In case of emergency shutdown, the safety oil pressure drops to zero, the hydraulic check valve closes, and the control circuit is cut off through hydraulic interlock. Even if the servo valve fails to control, the valve can be quickly closed to ensure the safety of the unit.

[0019] 2. This utility model can effectively determine the working status of two servo control oil circuits. Specifically, when the solenoid valve in the first servo control oil circuit is energized, the pressure at the corresponding hydraulic check valve control port decreases, the normally closed contact of the corresponding pressure switch closes, and the hydraulic check valve locks and isolates that servo control oil circuit. Conversely, when the solenoid valve is de-energized, the pressure at the corresponding hydraulic check valve control port increases, the normally closed contact of the corresponding pressure switch opens, and the hydraulic check valve opens to control the operation of that servo control oil circuit.

[0020] 3. The hydraulic control check valve of this utility model has an internal leakage rate of 1 to 2 drops of oil per minute, which can completely isolate the servo valve control circuit. In the steady state, the valve position is more stably controlled by a single servo valve.

[0021] 4. In the event of a loss of power oil, the valve can be closed by a reset spring, effectively ensuring the safety of the machine.

[0022] 5. This utility model hinges the piston rod of the hydraulic actuator to the valve lever mechanism and the rear end cover of the hydraulic cylinder to the bracket, which helps to significantly reduce the lateral force borne by the piston rod when the hydraulic actuator is working. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the structure of this utility model;

[0024] The markings in the diagram are as follows: 1. Servo control oil circuit, 2. Shutdown oil circuit, 3. Hydraulic actuator, 4. Pressure oil passage, 5. Safety oil passage, 6. Oil drain passage, 7. Servo valve, 8. Solenoid valve I, 9. Hydraulic check valve I, 10. Hydraulic check valve II, 11. Pressure switch, 12. Throttling orifice, 13. Cartridge valve, 14. Solenoid valve II, 15. Throttling adjustment valve I, 16. Throttling adjustment valve II, 17. Dual oil filter, 18. Return spring, 19. Lever mechanism. Detailed Implementation

[0025] like Figure 1 As shown, this utility model provides a safety control device for a regulating valve, including a servo control oil circuit 1, a shut-off oil circuit 2, a hydraulic actuator 3, a pressure oil passage 4, a safety oil passage 5, and an oil discharge passage 6. The pressure oil passage 4 has branches, which are connected to the rod-side chamber and the rodless chamber of the hydraulic actuator 3 respectively. The servo control oil circuit 1 has at least two paths. Based on cost and reliability, it is preferred that the servo control oil circuit 1 has two paths. The two servo control oil circuits 1 are redundantly connected in parallel between the pressure oil passage 4 and the rodless chamber of the hydraulic actuator 3. Each servo control oil circuit 1 includes a servo valve 7, a solenoid valve I 8, a hydraulic check valve I 9, a hydraulic check valve II 10, and a pressure switch 11. The oil inlet of the servo valve 7 is connected to the pressure oil passage 4. The control oil port of the servo valve 7 is connected to the hydraulic check valve I 9 and the hydraulic check valve II 10 in sequence, and the unidirectional flow directions of the hydraulic check valve I 9 and the hydraulic check valve II 10 are opposite. The hydraulic check valve II 10 is connected to the rodless chamber of the hydraulic motor 3. The oil outlet of the solenoid valve I 8 is connected to the hydraulic check valve I 9, the hydraulic check valve II 10, and the pressure switch 11. The safety oil passage 5 is connected to the pressure oil passage 4 through a throttle orifice 12. The pressure oil enters the safety oil passage 5 after passing through the throttle orifice 12 to form safety oil. The shut-off oil circuit 2 is connected to the safety oil circuit 5, the pressure oil circuit 4, and the oil inlet of the solenoid valve I8, respectively. The oil outlet of the servo valve 7, the oil outlet of the solenoid valve I8, and the oil outlet of the shut-off oil circuit 2 are all connected to the oil outlet channel 6.

[0026] Furthermore, the aforementioned shut-off oil circuit 2 includes a cartridge valve 13 and two redundant solenoid valves II 14. The inlet of solenoid valve II 14 is connected to the safety oil passage 5, and the outlet of solenoid valve II 14 is connected to the control chamber of cartridge valve 13 and the inlet of solenoid valve I 8, respectively. The outlet of solenoid valve II 14 is connected to the drain channel 6. The safety oil in the safety oil passage 5 can enter solenoid valve I 8 through solenoid valve II 14, and then enter hydraulic check valve I 9, hydraulic check valve II 10 and pressure switch 11 through solenoid valve I 8. The inlet of cartridge valve 13 is connected to the pressure oil passage 4, and the outlet of cartridge valve 13 is connected to the rodless chamber of the hydraulic actuator 3.

[0027] In one specific embodiment, the pressure oil passage 4 is equipped with a switchable dual oil filter 17. In the dual oil filter 17, one filter is in operation while the other is on standby. After being filtered by the dual oil filter 17, the pressure oil enters the servo control oil circuit 1, the shut-off oil circuit 2, and the hydraulic actuator 3. The dual oil filter 17 can filter impurities in the pressure oil, preventing the servo valve 7 from jamming.

[0028] In one specific embodiment, in each servo control oil circuit 1, a throttling adjustment valve I 15 is provided at the front end of the oil inlet of the servo valve 7, and a throttling adjustment valve II 16 is provided at the rear end of the hydraulic check valve II 10. Specifically, the throttling adjustment valve I 15 is located between the oil inlet of the servo valve 7 and the dual oil filter 17, and the throttling adjustment valve II 16 is located between the hydraulic check valve II 10 and the rodless chamber of the hydraulic actuator 3. By closing the throttling adjustment valve I 15 and the throttling adjustment valve II 16, the faulty servo valve can be replaced online.

[0029] In one specific embodiment, both solenoid valve I8 and solenoid valve II14 are two-position three-way single-coil solenoid valves. When the solenoid valve coil is de-energized, the oil inlet P is connected to the oil outlet B, and the oil drain port T is blocked. When the solenoid valve coil is energized, the oil drain port T is connected to the oil outlet B, and the oil inlet P is blocked. This solenoid valve has a small internal leakage, only 1-2 drops of oil per minute.

[0030] In one specific embodiment, the rear end cover of the hydraulic cylinder of the hydraulic actuator 3 is hinged to the bracket, and a return spring 18 is installed on the piston rod of the hydraulic actuator 3, and a lever mechanism 19 for opening and closing the regulating valve is hinged thereto. This reduces the lateral force on the piston rod of the hydraulic actuator 3 during operation, which helps to reduce the lateral force on the piston rod during operation and avoids the problems of seal failure and piston rod bending.

[0031] It should be noted that the aforementioned servo valve 7 is a four-way spool valve with zero opening and linear gain. The flow rate of servo valve 7 can be 63 L / min (when the pressure difference at each throttling edge is 3.5 MPa). When there is no control signal, the inlet P of servo valve 7 is connected to the control port B, and the control port A is connected to the outlet T. The hydraulically controlled check valve has a flow rate of 120 L / min, a cartridge structure, and low internal leakage, with only 1-2 drops of oil per minute.

[0032] The functional safety provided by this utility model includes:

[0033] Servo valve 7 can close when there is no control signal. When not powered, servo valve 7 is set to mechanical zero offset (oil port P→B), so that when the control signal is lost, the pressure oil passes through servo valve 7 and enters the rodless chamber of hydraulic motor 3, so that the valve can close automatically.

[0034] When the safety oil pressure disappears, the control circuit of the two servo control oil circuits 1 is cut off, and the pressure oil at the inlet quickly enters the rodless chamber of the oil motor 3 through the outlet, driving the regulating valve to close quickly.

[0035] The valve can close when the oil supply pressure disappears. A return spring 18 is installed on the piston rod of the oil motor 3. The return spring 18 pushes the lever mechanism 19 to fully close the valve, which improves safety.

[0036] In this invention, when controlling the turbine regulating valve, the pressurized oil in the pressure oil passage 4 first enters the rod chamber of the hydraulic actuator 3, the throttle orifice 12, and the two servo valves 7 of the two servo control oil circuits 1. The pressurized oil entering the two servo valves 7 adjusts the oil flow according to the command signal from the control system. The two solenoid valves 18 in the two servo control oil circuits 1 select one servo control oil circuit 1 to be engaged and the other to be on standby according to the command from the control system. For example, setting... Figure 1 The left and right servo control oil circuits 1 are oil circuit I and oil circuit II, respectively.

[0037] When solenoid valve I8 in oil circuit I is de-energized and conducts, the normally closed contact of the corresponding pressure switch 11 opens, and solenoid valve I8 in oil circuit II is energized and isolated. At this time, safety oil enters solenoid valve I8 in oil circuit I through solenoid valve II14, and then enters the control ports of hydraulic check valve I9 ​​and hydraulic check valve II10 through solenoid valve I8 in oil circuit I. Hydraulic check valve I9 ​​and hydraulic check valve II10 open, and the pressure oil in oil circuit I through servo valve 7 can enter the rodless chamber of hydraulic motor 3 through hydraulic check valve I9, hydraulic check valve II10 and throttle adjustment valve II16. Thus, the turbine regulating valve can be controlled through oil circuit I.

[0038] Conversely, when solenoid valve I8 in oil circuit II is de-energized and conducts, the normally closed contact of the corresponding pressure switch 11 opens, and solenoid valve I8 in oil circuit I is energized and isolated. At this time, when safety oil is supplied, solenoid valve I8 in oil circuit II enters the control port of hydraulic check valve I9 ​​and hydraulic check valve II10. Hydraulic check valve I9 ​​and hydraulic check valve II10 open, and the pressure oil in oil circuit II via servo valve 7 can enter the rodless chamber of hydraulic motor 3 through hydraulic check valve I9, hydraulic check valve II10 and throttle adjustment valve II16. Thus, the turbine regulating valve can be controlled through oil circuit II.

[0039] When the unit is running normally, the control system issues a command to energize the two solenoid valves II14 in the shut-off oil circuit 2. The safety oil enters the control chamber of the cartridge valve 13 and the solenoid valve I8 of the two servo control oil circuits 1 through the two solenoid valves II14. The valve core of the cartridge valve 13 closes under the action of the safety oil, cutting off the oil inlet and outlet of the cartridge valve 13.

[0040] In an emergency, the control system issues a command to de-energize the two solenoid valves II14. The safety oil in the control chamber of cartridge valve 13 and the safety oil in the hydraulic check valve enter the drain channel 6 through solenoid valve II14. The hydraulic check valves I9 and II10 close, and the two servo control oil circuits 1 cannot control the hydraulic motor 3 through the servo valve 7. At the same time, the valve core of cartridge valve 13 opens, and the pressure oil at the inlet of cartridge valve 13 quickly enters the rodless chamber of the hydraulic motor 3 through the outlet, driving the regulating valve to close quickly.

[0041] The above description is only a specific embodiment of the present utility model. Any feature disclosed in this specification may be replaced by other equivalent or similar features unless otherwise specified. All features or steps in all methods or processes disclosed may be combined in any way except for mutually exclusive features and / or steps.

Claims

1. A safety control device for a regulating valve, characterized in that: The system includes a servo control oil circuit (1), a shut-off oil circuit (2), a hydraulic motor (3), a pressure oil passage (4), a safety oil passage (5), and an oil drain passage (6). The pressure oil passage (4) is connected to the rod-side and rodless-side chambers of the hydraulic motor (3), respectively. The servo control oil circuit (1) is redundantly connected in parallel between the pressure oil passage (4) and the rodless-side chamber of the hydraulic motor (3). Each servo control oil circuit (1) includes a servo valve (7), a solenoid valve I (8), a hydraulic check valve I (9), a hydraulic check valve II (10), and a pressure switch (11). The oil inlet of the servo valve (7) is connected to the pressure oil passage (4), and the control oil port of the servo valve (7) is connected to the hydraulic check valve I (9) and the hydraulic check valve II (10) in sequence. One-way valve II (10), and the one-way flow direction of hydraulic control one-way valve I (9) is opposite to that of hydraulic control one-way valve II (10). Hydraulic control one-way valve II (10) is connected to the rodless chamber of the hydraulic motor (3). The oil outlet of solenoid valve I (8) is connected to hydraulic control one-way valve I (9), hydraulic control one-way valve II (10) and pressure switch (11) respectively. The safety oil passage (5) is connected to the pressure oil passage (4) through the throttle hole (12). The shut-off oil passage (2) is connected to the safety oil passage (5), pressure oil passage (4) and the oil inlet of solenoid valve I (8) respectively. The oil outlet of servo valve (7), the oil outlet of solenoid valve I (8) and the oil outlet of shut-off oil passage (2) are all connected to the oil outlet channel (6).

2. The safety control device for a regulating valve according to claim 1, characterized in that: The shut-off oil circuit (2) includes a cartridge valve (13) and two redundant solenoid valves II (14). The inlet of solenoid valve II (14) is connected to the safety oil passage (5). The outlet of solenoid valve II (14) is connected to the control chamber of cartridge valve (13) and the inlet of solenoid valve I (8) respectively. The outlet of solenoid valve II (14) is connected to the drain channel (6). The inlet of cartridge valve (13) is connected to the pressure oil passage (4). The outlet of cartridge valve (13) is connected to the rodless chamber of the hydrator (3).

3. A safety control device for a regulating valve according to claim 1 or 2, characterized in that: The servo valve (7) is equipped with a throttling adjustment valve I (15) at the front end of the oil inlet.

4. A safety control device for a regulating valve according to claim 1 or 2, characterized in that: The rear end of the hydraulic control check valve II (10) is provided with a throttling adjustment valve II (16).

5. A safety control device for a regulating valve according to claim 1 or 2, characterized in that: The pressure oil passage (4) is equipped with a dual oil filter (17). After the pressure oil is filtered by the dual oil filter (17), it enters the servo control oil circuit (1), the shut-off oil circuit (2) and the oil motor (3).

6. The safety control device for a regulating valve according to claim 1, characterized in that: The cylinder rear end cover of the hydraulic actuator (3) is hinged to the bracket, and a return spring (18) is installed on the piston rod of the hydraulic actuator (3), and a lever mechanism (19) for opening and closing the regulating valve is hinged thereto.

7. The safety control device for a regulating valve according to claim 1, characterized in that: Both solenoid valve I (8) and solenoid valve II (14) are two-position three-way single-coil solenoid valves.

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