A gas control valve opening and closing and valve position keeping system

Abstract

The present invention discloses a gas-controlled valve opening and closing and valve position holding system, which is mainly composed of an air source, a ball valve, a one-way valve, a two-position five-way pneumatic control valve, a double-acting cylinder, and an air lock valve. The air source is used to provide a power source for the entire action system, the two-position five-way pneumatic control valve is used to switch the direction of the air source, and the air lock valve is used to lock the position of the double-acting cylinder after the air source loses air. The double-acting cylinder is used as an actuator to drive the valve to open and close. The present invention can control the opening and closing of the valve and the valve position holding only by gas, without the need to use a solenoid valve or electricity, and can meet the needs of special applications that require valve position holding but cannot have power access.

Description

Technical Field

[0001] The invention belongs to the technical field of valve position keeping control, and in particular relates to a gas control valve opening and closing and valve position keeping system. Background Art

[0002] In the current common valve position keeping control system, a combination of a two-position five-way solenoid valve and an air lock valve is generally used to control the cylinder to achieve the opening and closing of the valve and the valve position keeping function. In the above system, the cylinder can only be opened and closed when the solenoid valve is ventilated and powered. When the power is off or the gas is cut off, the air lock valve keeps the cylinder in position. In some special occasions, it is required to keep the valve position, but there is no power supply. Obviously, the valve opening and closing and valve position keeping system controlled by the solenoid valve cannot meet the requirements.

[0003] Chinese patent CN102976105B discloses an air circuit control system of a spherical air lock valve, including a cylinder, an air bag, and a solenoid valve; the air inlet of the solenoid valve is connected to the air bag through a pipeline; the two air outlets of the solenoid valve are respectively connected to the closed air port and the open air port of the cylinder through pipelines; the air outlet of the solenoid valve connected to the closed air port of the cylinder is connected to a branch pipeline and connected to the sealing ring of the air lock valve; a pilot valve is connected to the pipeline between the open air port of the cylinder and the air outlet of the solenoid valve, the control air port of the pilot valve is connected to the sealing ring of the air lock valve, and a mechanical control valve is connected to the branch pipeline, which is driven and triggered by the valve core of the air lock valve, and can ensure the effective sealing of the valve in the event of accidental power failure or air loss, thereby achieving the purpose of zero leakage. Summary of the invention

[0004] In order to meet the needs of special application occasions that require valve position maintenance but cannot have power access, the present invention provides a gas control valve opening and closing and valve position maintenance system.

[0005] The technical solution of the present invention uses only gas to control the opening and closing of the valve and the valve position maintenance, which can meet the needs of special application occasions that require valve position maintenance but cannot have power access.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] The present invention provides a gas control valve opening and closing and valve position keeping system, comprising a gas source, a first ball valve, a second ball valve, a two-position five-way gas control valve, a gas lock valve and a double-acting cylinder.

[0008] The gas source is used to provide a power source for the entire action system, and the gas source leads to a first branch and a second branch.

[0009] The first branch leads to the third branch and the fifth branch, the second branch leads to the fourth branch and the sixth branch, the fifth branch and the sixth branch are connected to the seventh branch at the same time, the seventh branch leads to the eighth branch and the ninth branch, the third branch, the fourth branch and the ninth branch are respectively connected to the two-position five-way air control valve, the eighth branch is connected to the air lock valve,

[0010] The two-position five-way air control valve and the air lock valve are connected via a first connecting pipeline and a second connecting pipeline.

[0011] The air lock valve and the double-acting cylinder are connected via a third connecting pipeline and a fourth connecting pipeline;

[0012] The first ball valve is arranged on the first branch and is used to connect or cut off the gas source;

[0013] The second ball valve is arranged on the second branch and is used to connect or cut off the gas source;

[0014] The two-position five-way air control valve is used to switch the direction of the air source;

[0015] The air lock valve is used to lock the position of the double-acting cylinder after the air source fails;

[0016] The double-acting cylinder is used to be connected to an external valve and serves as an actuator for driving the external valve to open and close.

[0017] In one embodiment of the present invention, a first one-way valve is provided on the fifth branch, and the opening direction of the first one-way valve is from the gas source to the two-position five-way gas-controlled valve, so as to prevent the medium from flowing back.

[0018] In one embodiment of the present invention, a second one-way valve is provided on the sixth branch, and the opening direction of the second one-way valve is from the gas source to the two-position five-way gas-controlled valve, so as to prevent the medium from flowing back.

[0019] In one embodiment of the present invention, the two-position five-way air-controlled valve is provided with five interfaces, namely, an A interface, a B interface, an R interface, a P interface, and an S interface. The first branch is connected to the P interface, and the P interface can be connected to the A interface, or can be connected to the B interface. The A interface of the two-position five-way air-controlled valve is connected to the first connecting pipeline, and the B interface of the two-position five-way air-controlled valve is connected to the second connecting pipeline.

[0020] In one embodiment of the present invention, the air lock valve has a connection port, a connection port, a connection port, and a connection port. The connection port a and the connection port b can be connected or disconnected, and the connection port c and the connection port d can be connected or disconnected. The connection port a is connected to the first connecting pipeline, the connection port c is connected to the second connecting pipeline, the connection port b is connected to the third connecting pipeline, and the connection port d is connected to the fourth connecting pipeline.

[0021] In one embodiment of the present invention, the double-acting cylinder has an A-end interface and a B-end interface, the A-end interface is connected to the third connecting pipeline, and the B-end interface is connected to the fourth connecting pipeline.

[0022] In one embodiment of the present invention, when the double-acting cylinder moves upward and maintains its position, the P interface of the two-position five-way air control valve is communicated with the B interface.

[0023] In one embodiment of the present invention, when the double-acting cylinder moves upward and maintains its position, the air flow direction of the first connecting pipeline is from the air lock valve to the two-position five-way air control valve, the air flow direction of the second connecting pipeline is from the two-position five-way air control valve to the air lock valve, the air flow direction of the third connecting pipeline is from the double-acting cylinder to the air lock valve, and the air flow direction of the fourth connecting pipeline is from the air lock valve to the double-acting cylinder.

[0024] In one embodiment of the present invention, when the double-acting cylinder moves downward and maintains its position, the P interface of the two-position five-way air control valve is communicated with the A interface.

[0025] In one embodiment of the present invention, when the double-acting cylinder moves downward and maintains its position, the air flow direction of the first connecting pipeline is from the air lock valve to the two-position five-way air control valve, the air flow direction of the second connecting pipeline is from the two-position five-way air control valve to the air lock valve, the air flow direction of the third connecting pipeline is from the double-acting cylinder to the air lock valve, and the air flow direction of the fourth connecting pipeline is from the air lock valve to the double-acting cylinder.

[0026] The gas circuit working principle of the gas control valve opening and closing and valve position holding system provided by the present invention is introduced as follows.

[0027] Cylinder upward movement and position retention:

[0028] Connect the gas source, open the first ball valve on the first branch, and the gas source is divided into the third branch and the fifth branch through the first branch. The gas source enters the two-position five-way gas control valve through the third branch, and opens the two-position five-way gas control valve; at the same time, the gas source pushes open the first one-way valve on the fifth branch and enters the seventh branch. After passing through the seventh branch, the gas source is divided into two branches: the eighth branch and the ninth branch. The gas source enters the signal source interface of the gas lock valve through the eighth branch, and the gas lock valve passage is opened, that is, the a connection port is connected to the b connection port, and the c connection port is connected to the d connection port; the gas source passes through the P interface and the B interface of the two-position five-way gas control valve through the ninth branch, and passes through the c connection port and the d connection port of the gas lock valve. The double-acting cylinder moves upward, that is, the valve opens. The double-acting cylinder moves upward to the required position and cuts off the gas source. At this time, because the gas source pressure at the gas source signal interface of the gas lock valve is less than the set locking pressure, the gas lock valve returns to the initial position, the a connection port is cut off from the b connection port, the c connection port is cut off from the d connection port, the remaining gas between the double-acting cylinder and the gas lock valve is locked, and the double-acting cylinder maintains its position unchanged, that is, the valve is kept in place.

[0029] Cylinder down and position retention:

[0030] Connect the gas source, open the second ball valve on the second branch, and the gas source is divided into the fourth branch and the sixth branch through the second branch. The gas source enters the two-position five-way gas control valve through the fourth branch, and opens the two-position five-way gas control valve; at the same time, the gas source pushes the second one-way valve on the sixth branch to enter the seventh branch. After passing through the seventh branch, the gas source is divided into two branches: the eighth branch and the ninth branch. The gas source enters the signal source interface of the gas lock valve through the eighth branch, and the gas lock valve passage is opened, that is, the a connection port is connected to the b connection port, and the c connection port is connected to the d connection port; the gas source passes through the P interface and the A interface of the two-position five-way gas control valve through the ninth branch, and passes through the a connection port and the b connection port of the gas lock valve to enter the A end interface of the double-acting cylinder, and the double-acting cylinder moves downward, that is, the valve is closed. The double-acting cylinder moves downward to the required position and the gas source is cut off. At this time, because the gas source pressure at the gas source signal interface of the gas lock valve is less than the set locking pressure, the gas lock valve returns to the initial position, the a connection port is cut off from the b connection port, the c connection port is cut off from the d connection port, the remaining gas between the double-acting cylinder and the gas lock valve is locked, and the double-acting cylinder maintains its position unchanged, that is, the valve is kept in place.

[0031] Compared with the prior art, the gas control valve opening and closing and valve position holding system provided by the present invention mainly adopts gas source, ball valve, one-way valve, two-position five-way pneumatic control valve, double-acting cylinder, and gas lock valve. The gas source is used to provide power source for the entire action system, the two-position five-way pneumatic control valve is used to switch the direction of the gas source, and the gas lock valve is used to lock the position of the double-acting cylinder after the gas source loses gas. The double-acting cylinder is used as an actuator to drive the valve to open and close. The present invention can control the opening and closing of the valve and the valve position holding only by gas, without the need to use solenoid valves or electricity, and can meet the needs of special applications that require valve position holding but cannot have power access. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 It is a schematic diagram of the connection structure and operating principle of the gas control valve opening and closing and valve position holding system when the cylinder is in the upward and position holding state;

[0033] Figure 2 It is a schematic diagram of the connection structure and operating principle of the gas control valve opening and closing and valve position holding system when the cylinder is in the downward and position holding state.

[0034] The numbers in the figure show:

[0035] 1. Air source, 2. First ball valve, 3. Second ball valve, 4. First check valve, 5. Second check valve, 6. Two-position five-way air control valve, 7. Air lock valve, 8. Double-acting cylinder,

[0036] 9. The first branch, 10. The second branch, 11. The third branch, 12. The fourth branch, 13. The fifth branch, 14. The sixth branch, 15. The seventh branch, 16. The eighth branch, 17. The ninth branch, 18. The first connecting pipeline, 19. The second connecting pipeline, 20. The third connecting pipeline, 21. The fourth connecting pipeline. DETAILED DESCRIPTION

[0037] The present invention is described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] It should be noted that all directional indications in the embodiments of the present invention (such as up, down, left, right, front, back, etc.) are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0039] In addition, in the present invention, descriptions such as "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" or "second" may explicitly or implicitly include at least one of the features. In the description of the present invention, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0040] In the present invention, unless otherwise clearly defined and limited, the terms "connection", "fixation" and the like should be understood in a broad sense. For example, "fixation" can be a fixed connection, a detachable connection, or an integral connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0041] In addition, the technical solutions between the various embodiments of the present invention can be combined with each other, but it must be based on the fact that ordinary technicians in the field can implement it. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by the present invention.

[0042] Example

[0043] refer to Figure 1 and Figure 2The present embodiment provides a gas control valve opening and closing and valve position holding system, including a gas source 1, a first ball valve 2, a second ball valve 3, a two-position five-way gas control valve 6, a gas lock valve 7 and a double-acting cylinder 8. The gas source 1 is used to provide a power source for the entire action system. The gas source 1 leads to a first branch 9 and a second branch 10. The first branch 9 leads to a third branch 11 and a fifth branch 13. The second branch 10 leads to a fourth branch 12 and a sixth branch 14. The fifth branch 13 and the sixth branch 14 are simultaneously connected to the seventh branch 15. The seventh branch 15 leads to an eighth branch 16 and a ninth branch 17. The third branch 11, the fourth branch 12 and the ninth branch 17 are respectively connected to the two-position five-way gas control valve 6, the eighth branch 16 is connected to the air lock valve 7, the two-position five-way air control valve 6 and the air lock valve 7 are connected through the first connecting pipeline 18 and the second connecting pipeline 19, and the air lock valve 7 and the double-acting cylinder 8 are connected through the third connecting pipeline 20 and the fourth connecting pipeline 21; the first ball valve 2 is arranged on the first branch 9, and is used to connect or cut off the air source; the second ball valve 3 is arranged on the second branch 10, and is used to connect or cut off the air source; the two-position five-way air control valve 6 is used to switch the direction of the air source; the air lock valve 7 is used to lock the position of the double-acting cylinder 8 after the air source loses air; the double-acting cylinder 8 is used to be connected to an external valve as an actuator for driving the external valve to open and close.

[0044] In this embodiment, a first one-way valve 4 is provided on the fifth branch 13, and the opening direction of the first one-way valve 4 is from the gas source 1 to the two-position five-way gas control valve 6, so as to prevent the medium from flowing back. A second one-way valve 5 is provided on the sixth branch 14, and the opening direction of the second one-way valve 5 is from the gas source 1 to the two-position five-way gas control valve 6, so as to prevent the medium from flowing back.

[0045] In this embodiment, the two-position five-way air control valve 6 is provided with five interfaces, namely, A interface, B interface, R interface, P interface, and S interface. The first branch 9 is connected to the P interface, and the P interface can be connected to the A interface, or can be connected to the B interface. The A interface of the two-position five-way air control valve 6 is connected to the first connecting pipeline 18, and the B interface of the two-position five-way air control valve 6 is connected to the second connecting pipeline 19.

[0046] The air lock valve 7 has a connection port a, a connection port b, a connection port c, and a connection port d. The connection port a and the connection port b can be connected or disconnected, and the connection port c and the connection port d can be connected or disconnected. The connection port a is connected to the first connecting pipeline 18, the connection port c is connected to the second connecting pipeline 19, the connection port b is connected to the third connecting pipeline 20, and the connection port d is connected to the fourth connecting pipeline 21.

[0047] The double-acting cylinder 8 has an A-end interface and a B-end interface, the A-end interface is connected to the third connecting pipeline 20 , and the B-end interface is connected to the fourth connecting pipeline 21 .

[0048] In this embodiment, when the double-acting cylinder 8 moves upward and maintains its position, the P interface of the two-position five-way air control valve 6 is connected to the B interface. When the double-acting cylinder 8 moves upward and maintains its position, the airflow direction of the first connecting pipeline 18 is from the air lock valve 7 to the two-position five-way air control valve 6, the airflow direction of the second connecting pipeline 19 is from the two-position five-way air control valve 6 to the air lock valve 7, the airflow direction of the third connecting pipeline 20 is from the double-acting cylinder 8 to the air lock valve 7, and the airflow direction of the fourth connecting pipeline 21 is from the air lock valve 7 to the double-acting cylinder 8.

[0049] When the double-acting cylinder 8 moves downward and maintains its position, the P interface of the two-position five-way air control valve 6 is connected to the A interface. When the double-acting cylinder 8 moves downward and maintains its position, the airflow direction of the first connecting pipeline 18 is from the air lock valve 7 to the two-position five-way air control valve 6, the airflow direction of the second connecting pipeline 19 is from the two-position five-way air control valve 6 to the air lock valve 7, the airflow direction of the third connecting pipeline 20 is from the double-acting cylinder 8 to the air lock valve 7, and the airflow direction of the fourth connecting pipeline 21 is from the air lock valve 7 to the double-acting cylinder 8.

[0050] The working principle of the gas circuit of the gas control valve opening and closing and valve position holding system provided in this embodiment is described as follows:

[0051] Cylinder upward movement and position retention:

[0052] Further references Figure 1 , connect the gas source 1, open the first ball valve 2 on the first branch 9, and the gas source is divided into the third branch 11 and the fifth branch 13 through the first branch 9. The gas source enters the two-position five-way gas control valve 6 through the third branch 11, and opens the two-position five-way gas control valve 6; at the same time, the gas source pushes the first check valve 4 on the fifth branch 13 and enters the seventh branch 15. After passing through the seventh branch 15, the gas source is divided into two paths: the eighth branch 16 and the ninth branch 17. The gas source enters the signal source interface of the gas lock valve 7 through the eighth branch 16, and the passage of the gas lock valve 7 is opened, that is, the a connection port is connected to the b connection port, and the c connection port is connected to the d connection port; the gas source passes through the P interface and the B interface of the two-position five-way gas control valve 6 through the ninth branch 17, and enters the B end interface of the double-acting cylinder 8 through the c connection port and the d connection port of the gas lock valve 7, and the double-acting cylinder 8 moves upward, that is, the valve is opened. The double-acting cylinder 8 moves upward to the required position and cuts off the gas source 1. At this time, because the air source pressure at the air source signal interface of the air lock valve 7 is less than the set locking pressure, the air lock valve 7 returns to the initial position, the a connection port is cut off from the b connection port, and the c connection port is cut off from the d connection port, so that the remaining air between the double-acting cylinder 8 and the air lock valve 7 is locked, and the double-acting cylinder 8 keeps its position unchanged, that is, the valve is kept in place.

[0053] Cylinder down and position retention:

[0054] Further references Figure 2 , connect the gas source 1, open the second ball valve 3 on the second branch 10, and the gas source is divided into the fourth branch 12 and the sixth branch 14 through the second branch 10. The gas source enters the two-position five-way gas control valve 6 through the fourth branch 12, and opens the two-position five-way gas control valve 6; at the same time, the gas source pushes the second one-way valve 5 on the sixth branch 14 to enter the seventh branch 15. After passing through the seventh branch 15, the gas source is divided into two paths: the eighth branch 16 and the ninth branch 17. The gas source enters the signal source interface of the gas lock valve 7 through the eighth branch 16, and the passage of the gas lock valve 7 is opened, that is, the a connection port is connected to the b connection port, and the c connection port is connected to the d connection port; the gas source passes through the P interface and the A interface of the two-position five-way gas control valve 6 through the ninth branch 17, and enters the A end interface of the double-acting cylinder 8 through the a connection port and the b connection port of the gas lock valve 7, and the double-acting cylinder 8 moves downward, that is, the valve is closed. The double-acting cylinder 8 moves downward to the required position and cuts off the gas source 1. At this time, because the air source pressure at the air source signal interface of the air lock valve 7 is less than the set locking pressure, the air lock valve 7 returns to the initial position, the a connection port is cut off from the b connection port, and the c connection port is cut off from the d connection port, so that the remaining air between the double-acting cylinder 8 and the air lock valve 7 is locked, and the double-acting cylinder 8 keeps its position unchanged, that is, the valve is kept in place.

[0055] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A gas control valve opening and closing and valve position keeping system, characterized in that: It comprises an air source (1), a first ball valve (2), a second ball valve (3), a two-position five-way air control valve (6), an air lock valve (7) and a double-acting cylinder (8). The gas source (1) is used to provide a power source for the entire action system. The gas source (1) leads to a first branch (9) and a second branch (10). The first branch (9) leads to a third branch (11) and a fifth branch (13); the second branch (10) leads to a fourth branch (12) and a sixth branch (14); the fifth branch (13) and the sixth branch (14) are simultaneously connected to a seventh branch (15); the seventh branch (15) leads to an eighth branch (16) and a ninth branch (17); the third branch (11), the fourth branch (12) and the ninth branch (17) are respectively connected to a two-position five-way air control valve (6); the eighth branch (16) is connected to an air lock valve (7); The two-position five-way air control valve (6) and the air lock valve (7) are connected via a first connecting pipeline (18) and a second connecting pipeline (19). The air lock valve (7) and the double-acting cylinder (8) are connected via a third connecting pipeline (20) and a fourth connecting pipeline (21); The first ball valve (2) is arranged on the first branch (9) and is used to connect or cut off the gas source; The second ball valve (3) is arranged on the second branch (10) and is used to connect or cut off the gas source; The two-position five-way air control valve (6) is used to switch the direction of the air source; The air lock valve (7) is used to lock the position of the double-acting cylinder (8) after the air source fails. The double-acting cylinder (8) is used to be connected to an external valve and serves as an actuator for driving the external valve to open and close.

2. A gas control valve opening and closing and valve position keeping system according to claim 1, characterized in that: A first one-way valve (4) is arranged on the fifth branch (13), and the opening direction of the first one-way valve (4) is from the gas source (1) to the two-position five-way gas control valve (6), so as to prevent the medium from flowing back.

3. A gas control valve opening and closing and valve position keeping system according to claim 1, characterized in that: A second one-way valve (5) is provided on the sixth branch (14), and the opening direction of the second one-way valve (5) is from the gas source (1) to the two-position five-way gas control valve (6), so as to prevent the medium from flowing back.

4. A gas control valve opening and closing and valve position keeping system according to claim 1, characterized in that: The two-position five-way air control valve (6) is provided with an A interface, a B interface, and a P interface, the first branch (9) is connected to the P interface, the P interface can be connected to the A interface, or can be connected to the B interface, the A interface of the two-position five-way air control valve (6) is connected to the first connecting pipeline (18), and the B interface of the two-position five-way air control valve (6) is connected to the second connecting pipeline (19).

5. A gas control valve opening and closing and valve position keeping system according to claim 4, characterized in that: The air lock valve (7) has a connection port a, a connection port b, a connection port c, and a connection port d. The connection port a and the connection port b can be connected or disconnected, and the connection port c and the connection port d can be connected or disconnected. The connection port a is connected to a first connection pipeline (18), the connection port c is connected to a second connection pipeline (19), the connection port b is connected to a third connection pipeline (20), and the connection port d is connected to a fourth connection pipeline (21).

6. A gas control valve opening and closing and valve position keeping system according to claim 5, characterized in that: The double-acting cylinder (8) has an A-end interface and a B-end interface, the A-end interface is connected to the third connecting pipeline (20), and the B-end interface is connected to the fourth connecting pipeline (21).

7. A gas control valve opening and closing and valve position keeping system according to claim 4, characterized in that: When the double-acting cylinder (8) moves upward and maintains its position, the P interface of the two-position five-way air control valve (6) is connected to the B interface.

8. A gas control valve opening and closing and valve position keeping system according to claim 7, characterized in that: When the double-acting cylinder (8) moves upward and maintains its position, the airflow direction of the first connecting pipeline (18) is from the air lock valve (7) to the two-position five-way air control valve (6), the airflow direction of the second connecting pipeline (19) is from the two-position five-way air control valve (6) to the air lock valve (7), the airflow direction of the third connecting pipeline (20) is from the double-acting cylinder (8) to the air lock valve (7), and the airflow direction of the fourth connecting pipeline (21) is from the air lock valve (7) to the double-acting cylinder (8).

9. A gas control valve opening and closing and valve position keeping system according to claim 1, characterized in that: When the double-acting cylinder (8) moves downward and maintains its position, the P interface of the two-position five-way air control valve (6) is connected to the A interface.

10. A gas control valve opening and closing and valve position keeping system according to claim 9, characterized in that: When the double-acting cylinder (8) moves downward and maintains its position, the airflow direction of the first connecting pipeline (18) is from the air lock valve (7) to the two-position five-way air control valve (6), the airflow direction of the second connecting pipeline (19) is from the two-position five-way air control valve (6) to the air lock valve (7), the airflow direction of the third connecting pipeline (20) is from the double-acting cylinder (8) to the air lock valve (7), and the airflow direction of the fourth connecting pipeline (21) is from the air lock valve (7) to the double-acting cylinder (8).

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