A hydraulic control system for a double acting actuator

Abstract

The application discloses a hydraulic control system of a double-acting actuator, the double-acting actuator comprising a seat body, the seat body being internally divided into a rodless cavity and a rod cavity by a piston, the hydraulic control system comprising a main control valve, a working oil port of the main control valve being communicated with the rodless cavity; an oil supply oil path, comprising a first oil supply branch communicated with the rod cavity and a second oil supply branch communicated with an oil inlet P of the main control valve; an oil return oil path, the oil return oil path being communicated with an oil return port T of the main control valve; a safety quick-opening loop, comprising a first branch, a second branch and a third branch in parallel, the first branch being sequentially connected with a first electromagnetic valve and a second electromagnetic valve, the second branch being sequentially connected with a third electromagnetic valve and a fourth electromagnetic valve, and the third branch being sequentially connected with a fifth electromagnetic valve and a sixth electromagnetic valve. The application can avoid single-path failure leading to refusal to act, and meanwhile, redundancy reliability and anti-malfunction are considered, so that the stability of system operation is improved.

Description

Technical Field

[0001] This invention relates to the field of fluid pressure actuator technology, and in particular to a hydraulic control system for a double-acting actuator. Background Technology

[0002] In industries such as petrochemicals, coal chemicals, and power, emergency shut-off valves for critical process pipelines typically employ hydraulic actuators driven by double-acting cylinders. This allows for both regular valve opening adjustment and safe, rapid opening in emergency situations.

[0003] Currently, conventional valve opening regulation and emergency rapid switching functions are typically achieved through control loops formed by control valve assemblies. Among these, the valve safety rapid opening loops within the control loops often employ single-path or dual-path redundant designs. However, single-path safety loops are prone to failure to operate due to solenoid valve malfunctions or abnormal signals, failing to meet high-safety-level process requirements. Conversely, dual-path redundant loops are susceptible to valve malfunctions due to single-point false triggering, affecting the stable operation of the process system. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a hydraulic control system for a dual-acting actuator, which can avoid failure to operate due to single-path failure, while also ensuring redundancy, reliability, and prevention of maloperation, thereby improving the stability of system operation.

[0005] This invention is achieved through the following technical solution:

[0006] This invention provides a hydraulic control system for a double-acting actuator. The double-acting actuator includes a base, and the interior of the base has a rodless chamber and a rod chamber formed with a piston as the boundary. The cross-sectional area of ​​the rod chamber is smaller than that of the rodless chamber. A spring is provided inside the base on one side corresponding to the rod chamber. One end of the spring abuts against the end face of the piston, and the other end abuts against the base.

[0007] The hydraulic control system includes:

[0008] The main control valve includes an oil inlet P, an oil return port T, and a working port A, wherein the working port A of the main control valve is connected to the rodless chamber;

[0009] The oil supply circuit includes a first oil supply branch and a second oil supply branch that are interconnected. The first oil supply branch is connected to the rod chamber, and the second oil supply branch is connected to the oil inlet P of the main control valve.

[0010] The return oil circuit is connected to the return port T of the main control valve;

[0011] A safety quick-opening circuit is provided, wherein the inlet end of the safety quick-opening circuit is connected to the rodless cavity, and the outlet end is connected to the return oil circuit; the safety quick-opening circuit includes a first branch, a second branch, and a third branch connected in parallel; in the direction from the inlet end to the outlet end of the safety quick-opening circuit, the first branch is provided with a first solenoid valve and a second solenoid valve connected in series, the second branch is provided with a third solenoid valve and a fourth solenoid valve connected in series, and the third branch is provided with a fifth solenoid valve and a sixth solenoid valve connected in series;

[0012] The first solenoid valve and the third solenoid valve are electrically connected to a first pressure relay, the fourth solenoid valve and the fifth solenoid valve are electrically connected to a second pressure relay, and the sixth solenoid valve and the second solenoid valve are electrically connected to a third pressure relay.

[0013] Furthermore, the main control valve is a three-position four-way proportional solenoid valve.

[0014] Furthermore, a first throttle valve is connected in series between the inlet end of the first branch, the second branch, and the third branch and the rodless cavity.

[0015] Furthermore, the first throttle valve is an adjustable flow valve.

[0016] Furthermore, a second throttle valve is connected in series between the inlet end of the first branch, the second branch, and the third branch and the rodless cavity, and the second throttle valve is connected in parallel with the first throttle valve.

[0017] Furthermore, the second throttle valve is a fixed throttle valve.

[0018] Furthermore, the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve, and the sixth solenoid valve are all two-position two-way solenoid valves.

[0019] The oil inlet of the first solenoid valve is connected to the inlet end of the first branch, the oil outlet of the first solenoid valve is connected to the oil inlet of the second solenoid valve, and the oil outlet of the second solenoid valve is connected to the return oil circuit.

[0020] The oil inlet of the third solenoid valve is connected to the inlet end of the second branch, the oil outlet of the third solenoid valve is connected to the oil inlet of the fourth solenoid valve, and the oil outlet of the fourth solenoid valve is connected to the return oil circuit.

[0021] The oil inlet of the fifth solenoid valve is connected to the inlet end of the third branch, the oil outlet of the fifth solenoid valve is connected to the oil inlet of the sixth solenoid valve, and the oil outlet of the sixth solenoid valve is connected to the return oil circuit.

[0022] Furthermore, the first solenoid valve, the second solenoid valve, the third solenoid valve, the fourth solenoid valve, the fifth solenoid valve, and the sixth solenoid valve are energized under normal conditions, thereby disconnecting the passage between the oil inlet and the oil outlet of the solenoid valve.

[0023] When at least two of the first, second, and third pressure relays malfunction, causing the coil of the corresponding solenoid valve to lose power, at least one of the first, second, and third branches, the rodless chamber, is connected to the return oil circuit through the safety quick-opening circuit. At this time, the double-acting actuator performs a safety quick-opening action; otherwise, it does not perform a safety quick-opening action.

[0024] Furthermore, a third throttle valve is also provided on the second oil supply branch, and the third throttle valve is a fixed throttle valve.

[0025] Furthermore, a spring receiving cavity (140) for accommodating the spring is formed on the periphery of the rod cavity (130);

[0026] The hydraulic control system also includes an oil leakage recovery circuit, one end of which is connected to the spring receiving cavity and the other end of which is connected to the return oil circuit.

[0027] Compared with the prior art, the advantages of this invention are:

[0028] The hydraulic control system of the double-acting actuator in this embodiment of the invention employs three parallel branches in the safety quick-opening circuit. If any one branch fails, the other two can still trigger quick-opening, preventing single-branch failure from causing a failure to operate. Furthermore, each branch requires both solenoid valves to be simultaneously de-energized and conducting to release oil, avoiding false triggering due to a single point of failure and preventing valve malfunction. Three pressure relays control the first and third, fourth and fifth, and second and sixth solenoid valves respectively, forming a cross-interlock logic. Quick-opening is only triggered when a true emergency condition is met, balancing redundancy and reliability with prevention of false operation, thus improving the stability of system operation. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the hydraulic control system of a double-acting actuator according to an embodiment of the present invention.

[0030] Figure label:

[0031] 100. Double-acting actuator; 110. Piston; 120. Rodless chamber; 130. Rod chamber; 140. Spring receiving chamber; 150. Spring;

[0032] 10. Main control valve; 20. Oil supply circuit; 21. First oil supply branch; 22. Second oil supply branch; 23. Third throttle valve; 30. Return oil circuit; 40. Safety quick-opening circuit; 41. First solenoid valve; 42. Second solenoid valve; 43. Third solenoid valve; 44. Fourth solenoid valve; 45. Fifth solenoid valve; 46. Sixth solenoid valve; 47. First throttle valve; 48. Second throttle valve; 50. Leakage recovery circuit;

[0033] 1. First pressure relay; 2. Second pressure relay; 3. Third pressure relay. Detailed Implementation

[0034] The following detailed, non-limiting description of the invention's technical solutions, in conjunction with preferred embodiments and accompanying drawings, is provided. In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this invention, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0035] First, the dual-acting actuator of an embodiment of the present invention will be introduced. For example... Figure 1 As shown, the double-acting actuator 100 may include a base. Inside the base, a rodless chamber 120 and a rod chamber 130 are formed with the piston 110 as the boundary. The cross-sectional area of ​​the rod chamber 130 is smaller than that of the rodless chamber 120. Inside the base, corresponding to one side of the rod chamber 130, a spring 150 is provided. One end of the spring 150 abuts against the end face of the piston 110, and the other end abuts against the base. A spring receiving cavity 140 is formed around the rod chamber 130 to accommodate the spring 150.

[0036] Specifically, when the double-acting actuator 100 is in the forward drive mode, that is, pressurized fluid (e.g., oil) enters the rodless chamber 120, the pressure acts on the entire cross-section of the upper side of the piston 110 and generates thrust. The thrust overcomes the preload of the spring 150 and pushes the piston 110 downward, causing the piston rod to extend (at this time, the piston rod drives the valve body to close). The fluid in the rod chamber 130 is compressed and discharged, and the spring 150 is compressed, storing elastic potential energy. When the double-acting actuator 100 is in the reverse reset mode, that is, pressurized fluid enters the rod chamber 130, the pressure acts on the lower side of the piston 110, and at the same time, the spring 150 releases elastic potential energy, assisting in pushing the piston 110 upward. Simultaneously, the YV8 of the main control valve 10 is energized, the rodless chamber 120 is depressurized, the piston rod retracts (at this time, the piston rod drives the valve body to open), the fluid in the rodless chamber 120 is discharged through the main control valve 10, and the piston 110 returns to its initial position, completing the reset.

[0037] The hydraulic control system of the double-acting actuator according to an embodiment of the present invention will be described below.

[0038] This invention provides a hydraulic control system for a double-acting actuator, such as... Figure 1 As shown, the system may include a main control valve 10, an oil supply circuit 20, an oil return circuit 30, and a safety quick-opening circuit 40. The main control valve 10 is a three-position four-way proportional solenoid valve with an inlet P, an oil return port T, a working port A, and a working port B. Working port A is connected to the rodless chamber 120, and working port B is in a blocked state. The oil supply circuit 20 may include a first oil supply branch 21 and a second oil supply branch 22 that are interconnected. The first oil supply branch 21 is connected to the rod chamber 130, and the second oil supply branch 22 is connected to the inlet P of the main control valve 10. The oil return circuit 30 is connected to the oil return port T of the main control valve 10. The inlet end of the safety quick-opening circuit 40 is connected to the rodless chamber 120, and the outlet end is connected to the oil return circuit 30. The safety quick-opening circuit 40 includes a first branch, a second branch, and a third branch connected in parallel. In the direction from the inlet to the outlet of the safety quick-opening circuit 40, the first branch is provided with a first solenoid valve 41 and a second solenoid valve 42 connected in series, the second branch is provided with a third solenoid valve 43 and a fourth solenoid valve 44 connected in series, and the third branch is provided with a fifth solenoid valve 45 and a sixth solenoid valve 46 connected in series.

[0039] Among them, the first solenoid valve 41 and the third solenoid valve 43 are electrically connected to the first pressure relay 1, the fourth solenoid valve 44 and the fifth solenoid valve 45 are electrically connected to the second pressure relay 2, and the sixth solenoid valve 46 and the first solenoid valve 41 are electrically connected to the third pressure relay 3.

[0040] Specifically, in the normal state, the hydraulic control system of the double-acting actuator of the present invention is such that, since the main control valve 10 is a three-position four-way proportional solenoid valve (which can realize proportional adjustment of opening), it is not energized in the normal position. The oil inlet P, the oil return port T and the two working oil ports of the three-position four-way proportional solenoid valve are not connected to each other, and the piston 110 in the double-acting actuator 100 remains in the current position. When the YV7 electromagnet in the main control valve 10 is energized and reversed, the pressurized oil in the oil supply circuit 20 enters the inlet P of the main control valve 10 through the second oil supply branch 22, and then enters the rodless chamber 120 through the working oil port A. Meanwhile, the rod chamber 130 is continuously supplied with oil through the first oil supply branch 21. Since the rodless chamber 120 and the rod chamber 130 share the same hydraulic source (i.e., the pressure is the same), but there is a difference in cross-sectional area between them (the cross-sectional area of ​​the rodless chamber 120 is larger than that of the rod chamber 130), the piston 110 facing the rodless chamber 120 experiences greater pressure. This pressure drives the piston 110 in the double-acting actuator 100 to move downwards against the preload of the spring 150, and extends the piston rod to close the valve. Conversely, when the YV8 electromagnet is energized, oil returns from the rodless chamber 120, and the pressure in the rod chamber 130 pushes the piston 110 back, causing the piston rod to retract and open the valve.

[0041] When the piston rod extends and retracts normally, the first solenoid valve 41, the second solenoid valve 42, the third solenoid valve 43, the fourth solenoid valve 44, the fifth solenoid valve 45 and the sixth solenoid valve 46 in the safety quick-opening circuit 40 are normally energized and closed, the safety quick-opening circuit 40 is closed, and does not interfere with normal regulation.

[0042] As an example, the first solenoid valve 41, the second solenoid valve 42, the third solenoid valve 43, the fourth solenoid valve 44, the fifth solenoid valve 45, and the sixth solenoid valve 46 are all two-position two-way solenoid valves, each with an inlet and an outlet. The inlet of the first solenoid valve 41 is connected to the inlet of the first branch, and the outlet of the first solenoid valve 41 is connected to the inlet of the second solenoid valve 42. The outlet of the second solenoid valve 42 is connected to the return oil circuit 30. The inlet of the third solenoid valve 43 is connected to the inlet of the second branch, and the outlet of the third solenoid valve 43 is connected to the inlet of the fourth solenoid valve 44. The outlet of the fourth solenoid valve 44 is connected to the return oil circuit 30. The inlet of the fifth solenoid valve 45 is connected to the inlet of the third branch, and the outlet of the fifth solenoid valve 45 is connected to the inlet of the sixth solenoid valve 46. The outlet of the sixth solenoid valve 46 is connected to the return oil circuit 30.

[0043] That is, YV1, YV2, YV3, YV4, YV5 and YV6 of the first solenoid valve 41, the second solenoid valve 42, the third solenoid valve 43, the fourth solenoid valve 44, the fifth solenoid valve 45 and the sixth solenoid valve 46 are energized under normal conditions, so that the solenoid valve is in the cut-off position, and the passage between its oil inlet and oil outlet is disconnected.

[0044] The first pressure relay 1 is electrically connected to the electromagnet YV1 of the first solenoid valve 41 and the electromagnet YV3 of the third solenoid valve 43; the second pressure relay 2 is electrically connected to the electromagnet YV4 of the fourth solenoid valve 44 and the electromagnet YV5 of the fifth solenoid valve 45; and the third pressure relay 3 is electrically connected to the electromagnet YV4 of the sixth solenoid valve 46 and the electromagnet YV2 of the second solenoid valve 42. These three pressure relays control the energization of the electromagnets on the two solenoid valves of different branches. Therefore, if a single pressure relay malfunctions (the corresponding solenoid valve's electromagnet is de-energized), it does not affect the normal operation of each branch, and each branch remains blocked. Only when two or more pressure relays malfunction (to prevent single-point malfunction) will at least one branch of the safety quick-opening circuit 40 be open, and the rodless chamber 120 will be connected to the return oil circuit 30 through the safety quick-opening circuit 40, allowing the rodless chamber 120 to drain oil. At this time, the double-acting actuator performs a safety quick-opening action, that is, the piston 110 moves upward rapidly, realizing the safe and rapid opening of the valve driven by the piston rod. This ensures that the safety quick-opening circuit 40 will not be triggered in non-real emergency situations, ensuring safety and reliability.

[0045] It should be noted that the main control valve 10 is a three-position four-way proportional solenoid valve. By controlling the energization of solenoid YV7, the valve core opening is increased, the oil flow is increased, and thus the valve closes quickly. Similarly, by controlling the energization of solenoid YV8, the opening of the oil return port T is increased, and the rodless chamber 120 is connected to the oil return port T, achieving quick opening.

[0046] In other words, the hydraulic control system of the double-acting actuator in this embodiment of the invention employs three parallel branches in the safety quick-opening circuit. If any one branch fails, the other two can still trigger quick-opening, preventing single-branch failure from causing a failure to operate. Furthermore, each branch requires both solenoid valves to be simultaneously de-energized and conducting to release oil, avoiding false triggering due to a single point of failure and preventing valve malfunction. The three pressure relays respectively control the first and third, fourth and fifth, and second and sixth solenoid valves, forming a cross-interlock logic. Quick-opening is only triggered when a true emergency condition is met, balancing redundancy and reliability with prevention of false operation, thus improving the stability of system operation.

[0047] In some embodiments, such as Figure 1 As shown, in the safety quick-opening circuit 40, a first throttle valve 47 is connected in series between the inlet ends of the first branch, the second branch, and the third branch and the rodless chamber 120. Preferably, the first throttle valve 47 is an adjustable flow valve. In the safety quick-opening circuit 40, a second throttle valve 48 is also connected in series between the inlet ends of the first branch, the second branch, and the third branch and the rodless chamber 120. The second throttle valve 48 is connected in parallel with the first throttle valve 47. Preferably, the second throttle valve 48 is a fixed throttle valve.

[0048] In other words, an adjustable flow valve and a fixed throttle valve are connected in parallel between the interface of the rodless chamber 120 and the safety quick-opening circuit 40. The first throttle valve 47 is an adjustable flow valve, which can continuously adjust the flow area according to the on-site working conditions, load size, and actuator response speed requirements, precisely controlling the pressure relief rate of the rodless chamber 120, and avoiding mechanical shock, pipeline vibration, or valve water hammer caused by excessively rapid opening. The second throttle valve 48 is a fixed throttle valve, connected in parallel with the first throttle valve 47, forming a fixed minimum flow cross section. Even if the adjustable flow valve is manually closed, blocked, or malfunctions, the fixed throttle valve can still ensure that the pressure relief channel is unobstructed, ensuring that the actuator can open quickly in an emergency, structurally eliminating the risk of "safety circuit failure" and meeting a high safety level.

[0049] In some embodiments, such as Figure 1 As shown, a third throttle valve 23 is also provided on the second oil supply branch 22. The third throttle valve 23 is a fixed throttle valve.

[0050] Specifically, the third throttle valve 23 is connected in series on the second oil supply branch 22 to throttle and stabilize the pressure oil entering the oil inlet P of the main control valve 10, preventing oil supply pressure fluctuations and instantaneous impacts from directly acting on the main valve, so that the main control valve 10 operates under a stable and smooth control pressure, thereby improving the proportional control accuracy and action consistency.

[0051] In some embodiments, such as Figure 1 As shown, it also includes an oil leakage recovery circuit 50, one end of which is connected to the spring receiving cavity 140, and the other end is connected to the return oil circuit 30.

[0052] Specifically, the spring receiving cavity 140 is a sealed chamber. After the actuator has been working for a long time, a small amount of internal leakage oil from the rod cavity 130 will enter the spring receiving cavity 140. The oil leakage recovery circuit 50 is directly connected to the return oil circuit 30, which can continuously discharge the leaked oil, prevent the pressure inside the spring receiving cavity 140 from rising, and avoid increased resistance to piston 110 movement and jamming.

[0053] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A hydraulic control system for a double-acting actuator (100), the double-acting actuator (100) includes a base, the interior of the base having a rodless chamber (120) and a rod chamber (130) respectively formed with a piston (110) as the boundary, the cross-sectional area of ​​the rod chamber (130) being smaller than the cross-sectional area of ​​the rodless chamber (120); a spring (150) is provided inside the base and on one side corresponding to the rod chamber (130), one end of the spring (150) abutting against the end face of the piston (110), and the other end abutting against the base; Its features are, The hydraulic control system includes: The main control valve (10) includes an oil inlet P, an oil return port T and a working port A. The working port A of the main control valve (10) is connected to the rodless chamber (120). Oil supply circuit (20), the oil supply circuit (20) includes a first oil supply branch (21) and a second oil supply branch (22) that are interconnected. The first oil supply branch (21) is connected to the rod chamber (130), and the second oil supply branch (22) is connected to the oil inlet P of the main control valve (10). Return oil passage (30), the return oil passage (30) is connected to the return oil port T of the main control valve (10); A safety quick-opening circuit (40) is provided, with its inlet end connected to the rodless chamber (120) and its outlet end connected to the return oil circuit (30). The safety quick-opening circuit (40) includes a first branch, a second branch, and a third branch connected in parallel. In the direction from the inlet end to the outlet end of the safety quick-opening circuit (40), the first branch is provided with a first solenoid valve (41) and a second solenoid valve (42) connected in series, the second branch is provided with a third solenoid valve (43) and a fourth solenoid valve (44) connected in series, and the third branch is provided with a fifth solenoid valve (45) and a sixth solenoid valve (46) connected in series. The first solenoid valve (41) and the third solenoid valve (43) are electrically connected to a first pressure relay (1), the fourth solenoid valve (44) and the fifth solenoid valve (45) are electrically connected to a second pressure relay (2), and the sixth solenoid valve (46) and the second solenoid valve (42) are electrically connected to a third pressure relay (3).

2. The hydraulic control system for the double-acting actuator according to claim 1, characterized in that, The main control valve (10) is a three-position four-way proportional solenoid valve.

3. The hydraulic control system for the double-acting actuator according to claim 1, characterized in that, A first throttle valve (47) is connected in series between the inlet end of the first branch, the second branch and the third branch and the rodless cavity (120).

4. The hydraulic control system for the double-acting actuator according to claim 3, characterized in that, The first throttle valve (47) is an adjustable flow valve.

5. The hydraulic control system for the double-acting actuator according to claim 3, characterized in that, A second throttle valve (48) is connected in series between the inlet end of the first branch, the second branch and the third branch and the rodless cavity (120), and the second throttle valve (48) is connected in parallel with the first throttle valve (47).

6. The hydraulic control system for the double-acting actuator according to claim 5, characterized in that, The second throttle valve (48) is a fixed throttle valve.

7. The hydraulic control system for the double-acting actuator according to claim 1, characterized in that, The first solenoid valve (41), the second solenoid valve (42), the third solenoid valve (43), the fourth solenoid valve (44), the fifth solenoid valve (45), and the sixth solenoid valve (46) are all two-position two-way solenoid valves. The oil inlet of the first solenoid valve (41) is connected to the inlet end of the first branch, the oil outlet of the first solenoid valve (41) is connected to the oil inlet of the second solenoid valve (42), and the oil outlet of the second solenoid valve (42) is connected to the return oil circuit (30). The oil inlet of the third solenoid valve (43) is connected to the inlet end of the second branch, the oil outlet of the third solenoid valve (43) is connected to the oil inlet of the fourth solenoid valve (44), and the oil outlet of the fourth solenoid valve (44) is connected to the return oil circuit (30). The inlet of the fifth solenoid valve (45) is connected to the inlet of the third branch, the outlet of the fifth solenoid valve (45) is connected to the inlet of the sixth solenoid valve (46), and the outlet of the sixth solenoid valve (46) is connected to the return oil circuit (30).

8. The hydraulic control system for the double-acting actuator according to claim 7, characterized in that, The first solenoid valve (41), the second solenoid valve (42), the third solenoid valve (43), the fourth solenoid valve (44), the fifth solenoid valve (45), and the sixth solenoid valve (46) are energized under normal conditions, thereby disconnecting the passage between the oil inlet and outlet of the solenoid valve. When at least two of the first pressure relay (1), the second pressure relay (2), and the third pressure relay (3) malfunction, causing the coil of the corresponding solenoid valve to lose power, at least one of the first branch, the second branch, and the third branch, the rodless chamber (120), is connected to the return oil circuit (30) through the safety quick-opening circuit (40). At this time, the double-acting actuator performs a safety quick-opening action; otherwise, it does not perform a safety quick-opening action.

9. The hydraulic control system for the double-acting actuator according to claim 1, characterized in that, The second oil supply branch (22) is also provided with a third throttle valve (23), which is a fixed throttle valve.

10. The hydraulic control system for the double-acting actuator according to claim 1, characterized in that, The periphery of the rod cavity (130) is formed with a spring receiving cavity (140) for accommodating the spring (150); The hydraulic control system also includes an oil leakage recovery circuit (50), one end of which is connected to the spring receiving cavity (140), and the other end is connected to the return oil circuit (30).

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