Pneumatic stop valve and control method thereof

Abstract

The invention discloses a pneumatic stop valve and a control method thereof, and relates to the technical field of valve control, and the pneumatic stop valve comprises a main valve and a control loop. The main valve comprises a main valve body and a valve rod, a second cavity is formed in the main valve body, one end of the valve rod is provided with a valve clack, the other end of the valve rod is provided with a piston, and the piston is contained in the second cavity. The control loop comprises a control air source and at least two working reversing valves, all the working reversing valves are connected between the control air source and the main valve in parallel, each working reversing valve is provided with at least three switching ports, and a valve element of each working reversing valve can be switched among a first working position, a second working position and a third working position. The number of channels between the control gas source and the main valve is changed, so that the pressure loss amount of gas between the control gas source and a second cavity in the main valve is changed, the pressure of the gas in the second cavity is changed, and the distance between the valve clack and the first channel is changed. And the opening and closing degree of the main valve is controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of valve control, and in particular to a pneumatic stop valve and a control method thereof. Background Art

[0002] The stop valve is one of the most widely used valves due to its advantages such as small friction between the sealing surfaces during opening and closing, relatively durable, and small opening height. The stop valves currently used are mostly manually controlled to open and close the valves, with simple structure, low cost, and high reliability, but they cannot be remotely and automatically controlled, which is very inconvenient for the management of large-scale pipeline systems. Although there are also some stop valves currently used, most of them are manually controlled to open and close the valves, with simple structure, low cost, and high reliability, but they cannot be remotely and automatically controlled, which is very inconvenient for the management of large-scale pipeline systems. Although there are also some automatic control stop valves, they are all simple control of the opening and closing function of the stop valve, and cannot control the opening and closing size of the stop valve. In some occasions where the flow rate and pressure need to be controlled, it is also necessary to install additional throttle valves or pressure regulating valves to assist in controlling the flow rate or pressure of the gas in the main pipeline, which not only increases the cost, but also increases the complexity of the pipeline system, resulting in more joints in the main pipeline and increasing the risk of fluid leakage. Summary of the invention

[0003] In order to solve the problem that the stop valve has a single function and cannot control the opening and closing size, the present invention provides a pneumatic stop valve and a control method thereof.

[0004] The pneumatic stop valve provided in the present application includes a main valve and a control circuit. The main valve includes a main valve body and a valve stem. The main valve body has a first channel and a second channel that are interconnected. A first cavity is provided at the connection point between the first channel and the second channel. A second cavity is also provided in the main valve body. One end of the valve stem has a valve flap, and the other end has a piston. The valve flap is accommodated in the first cavity, and the piston is accommodated in the second cavity. The valve flap can block or open the first channel under the drive of the piston. The control circuit includes at least two working reversing valves and a control air source. All the working reversing valves are connected in parallel between the control air source and the second cavity. Each of the working reversing valves has at least three switching ports, which are respectively connected to the second cavity, the control air source and the atmosphere. The valve core of each working reversing valve can be switched between the first working position, the second working position and the third working position, so that different switching ports are connected to each other, thereby connecting or disconnecting the second cavity with the control air source or the atmosphere.

[0005] The principle of the present application is to change the number of passages between the control gas source and the second cavity, thereby changing the pressure loss of the gas from the control gas source to the second cavity in the main valve, and then changing the pressure of the gas in the second cavity, changing the distance between the valve disc and the first channel, and realizing control of the flow rate of the main valve.

[0006] Preferably, the control circuit includes eight working reversing valves, and the working reversing valves are three-position three-way electromagnetic reversing valves. More working reversing valves can more precisely control the opening and closing size of the main valve to adapt to occasions with higher requirements for the flow control accuracy of the main valve. At the same time, the electromagnetic reversing valve can realize remote control to improve the automation degree of the main valve.

[0007] Furthermore, the control circuit further includes a first communicating vessel and a second communicating vessel, wherein the first communicating vessel is used to connect all the working reversing valves with the second cavity, and the second communicating vessel is used to connect all the working reversing valves with the control gas source. The communicating vessel can conveniently connect multiple pipelines to each other, reduce the number of pipeline joints, and reduce the risk of gas leakage.

[0008] Furthermore, the control circuit further comprises a first cut-off valve and a second cut-off valve, the second communicating vessel is communicated with the first channel, the first cut-off valve is connected in series between the second communicating vessel and the first channel, and the second cut-off valve is connected in series between the control air source and the second communicating vessel. When the control air source fails, the airflow of the main pipeline can be introduced into the second cavity as the control air source to continue to control the main valve.

[0009] Furthermore, the control circuit further comprises a third shut-off valve and a standby reversing valve, wherein the third shut-off valve is connected in series between the first communicating vessel and the second cavity, and the standby reversing valve has at least a first gas path interface, a second gas path interface and a third gas path interface, wherein the first gas path interface is connected to an end of the first shut-off valve close to the first channel, the second gas path interface is connected to an end of the third shut-off valve close to the second cavity, and the third gas path interface is connected to the atmosphere. The valve core of the standby reversing valve can be switched between a fourth working position, a fifth working position and a sixth working position, so that the first gas path interface, the second gas path interface and the third gas path interface are interconnected, thereby connecting or disconnecting the second cavity with the control gas source or the atmosphere. When the control gas source fails or the working reversing valve cannot work normally, the control gas source can be disconnected from the working reversing valve, and the working reversing valve can be disconnected from the second cavity, and the opening and closing of the main valve can be controlled by the standby reversing valve, thereby improving the reliability of the control system.

[0010] Furthermore, a muffler is also provided on the third air path interface of the standby reversing valve. The muffler can reduce the noise during deflation and is commonly used in the field of pneumatic control.

[0011] In some embodiments, the control circuit further includes a pressure sensor and an electric control component, all the working reversing valves are electrically connected to the electric control component, the pressure sensor is electrically connected to the electric control component, and the pressure sensor is used to monitor the pressure value of the fluid in the second channel. The electric control component and the pressure sensor can be used to monitor the pressure value of the gas in the second channel in real time to achieve remote closed-loop control of the opening and closing of the main valve.

[0012] Specifically, the electric control component includes a PLC controller and a DC-DC switching power supply, the DC-DC switching power supply is electrically connected to all the working reversing valves, and the PLC controller is electrically connected to the DC-DC switching power supply. The PLC controller can realize remote control of the working reversing valve, and the DC-DC switching power supply is used to provide a DC control power supply for the electromagnetic reversing valve.

[0013] In some embodiments, the main valve further includes a spring, one end of which is connected to the valve flap, and the other end of which is connected to the main valve body. The spring can provide additional thrust for the valve flap, reducing the thrust required for the valve flap to move when closing the first channel, thereby reducing the air pressure required for the entire control circuit, and the pneumatic components used in the control circuit can select components with lower pressure, thereby reducing the cost of the control circuit.

[0014] The present application also provides a control method for the above-mentioned pneumatic stop valve, including a valve closing action stroke and a valve opening action stroke. The valve closing action stroke includes the following steps: S101. Determine the flow rate or pressure value of the gas that needs to flow out of the second channel, and determine the size of the opening and closing of the main valve based on this; S102. Controlling part or all of the valve cores of the working reversing valves to switch between the first working position, the second working position and the third working position, so that part or all of the working reversing valves connect the gas passage between the control gas source and the second cavity; S103. The control gas source delivers gas to the second cavity, so that the pressure in the second cavity increases, thereby pushing the piston to drive the valve disc to move toward the first channel; The valve opening action stroke comprises the following steps: S201. Determine the flow rate or pressure value of the gas that needs to flow out of the second channel, and determine the size of the opening and closing of the main valve based on this; S202. Control the valve core of some or all of the working reversing valves to switch between the first working position, the second working position and the third working position, so that some or all of the working reversing valves connect the second cavity with the atmosphere, so that the gas pressure in the second cavity decreases; S203. again controlling the valve core of part or all of the working reversing valves to switch between the first working position, the second working position and the third working position, so that part or all of the working reversing valves connect the gas passage between the control gas source and the second cavity; S204. The control gas source delivers gas to the second cavity to increase the pressure in the second cavity, thereby causing the piston to drive the valve flap to stop moving.

[0015] By using this method to control the pneumatic stop valve provided in the present application, the flow rate or pressure of the airflow passing through the stop valve can be controlled, and the speed regulating valve or throttle valve on the main pipe can be omitted, thus saving costs and reducing the risk of air leakage in the main pipe. In addition, the more working reversing valves are set in the control loop, the more accurate the opening and closing size of the stop valve can be adjusted.

[0016] Technical effects and advantages of the present invention: 1. By adding a control circuit with multiple working reversing valves, the number of passages between the control gas source and the second cavity can be changed, thereby changing the pressure loss of the gas from the control gas source to the second cavity in the main valve, and then changing the pressure of the gas in the second cavity, changing the distance between the valve disc and the first channel, that is, realizing the opening and closing size of the main valve and controlling the flow of the main valve. It also effectively reduces the number of pneumatic control components in the main pipeline, reduces the number of interfaces, and reduces the risk of gas leakage in the main pipeline.

[0017] 2. The number of working reversing valves can be increased or decreased according to the need for control accuracy to meet the needs of different scenarios. When more precise control of the opening and closing size of the main valve is required, the number of working reversing valves can be increased. When the opening and closing size of the main valve does not need to be controlled too precisely, the number of working reversing valves can be reduced to save costs.

[0018] 3. The control circuit can use low-voltage control elements, which can effectively reduce costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 This is a control principle diagram of a pneumatic stop valve according to a first embodiment of the present invention; Figure 2 A three-dimensional view of a pneumatic stop valve according to a second embodiment of the present invention; Figure 3 This is a control principle diagram of a pneumatic stop valve according to a third embodiment of the present invention; Figure 4 This is a control principle diagram of a pneumatic stop valve according to the fourth embodiment of the present invention.

[0020] The accompanying drawings are marked as follows: 1. main valve; 11. main valve body; 12. valve stem; 13. spring; 111. first channel; 112. second channel; 113. first cavity; 114. second cavity; 121. valve disc; 122. piston; 2. control circuit; 21. working reversing valve; 20. control air source; 23. first communicating vessel; 24. second communicating vessel; 25. first shut-off valve; 26. second shut-off valve; 27. third shut-off valve; 28. spare reversing valve; 29. ​​muffler; 210. pressure sensor; 220. electronic control component. DETAILED DESCRIPTION

[0021] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Embodiment 1 refer to Figure 1 As shown, the first embodiment of the present application provides a pneumatic stop valve, including a main valve 1 and a control circuit 2. The main valve 1 includes a main valve body 11 and a valve stem 12. The main valve body 11 has a first channel 111 and a second channel 112 that are interconnected. A first cavity 113 is provided at the connection between the first channel 111 and the second channel 112. A second cavity 114 is also provided in the main valve body 11. One end of the valve stem 12 has a valve flap 121, and the other end has a piston 122. The valve flap 121 is accommodated in the first cavity 113, and the piston 122 is accommodated in the second cavity 114. The valve flap 121 can block or open the first channel 111 driven by the piston 122. The control circuit 2 includes at least two working reversing valves 21 and a control air source 20. All the working reversing valves 21 are connected in parallel between the control air source 20 and the second cavity 114. Each working reversing valve 21 has at least three switching ports, which are respectively connected to the second cavity 114, the control air source 20 and the atmosphere. The valve core of each working reversing valve 21 can be switched between the first working position, the second working position and the third working position, so that different switching ports are connected to each other, thereby connecting or disconnecting the second cavity 114 with the control air source 20 or the atmosphere.

[0023] The principle of the present application is to change the number of passages between the control gas source 20 and the second cavity 114, thereby changing the pressure loss of the gas from the control gas source 20 to the second cavity 114, and then changing the pressure of the gas in the second cavity 114, changing the distance between the valve flap 121 and the first channel 111, and realizing the control of the flow of the main valve 1.

[0024] Specifically, Figure 1As shown, the control circuit 2 includes two working reversing valves 21, both of which are three-position three-way electromagnetic reversing valves, and each reversing valve has three switching ports A, P, and R, which can be connected to the second cavity 114, the control air source 20 and the atmosphere respectively. For example, the switching port A of the working reversing valve 21 is connected to the second cavity 114, the switching port P is connected to the control air source 20, and the switching port R is connected to the atmosphere. The valve core of the working reversing valve 21 can be switched between the first working position o, the second working position a, and the third working position b, wherein the first working position o is a normal position, that is, the default state when no control signal is applied. At this time, the switching port A, the switching port R, and the switching port P are not connected. When the valve core of the working reversing valve 21 is in the second working position a, the switching port A is connected to the switching port R, and when the valve core of the working reversing valve 21 is in the third working position b, the switching port A is connected to the switching port P.

[0025] When the flow of the main valve 1 needs to be reduced, the valve core of one of the working reversing valves 21 is switched to the third working position b, and the valve core of the other working reversing valve 21 is switched to the first working position o. At this time, there is only one passage from the control gas source 20 to the second cavity 114, namely the working reversing valve 21. The control gas source 20 delivers gas to the second cavity 114, so that the piston 122 drives the valve disc 121 to move toward the first channel 111. As the gap between the valve disc 121 and the first channel 111 decreases, the pressure of the gas in the first channel 111 on the valve disc 121 gradually increases until it is balanced with the thrust applied by the piston 122, so that the valve disc 121 stops moving and remains stationary. The flow of the main valve 1 remains stable after it decreases to a certain value.

[0026] When the main valve 1 needs to be closed, the valve core of the working reversing valve 21 is switched to the third working position b. At this time, the control gas source 20 can deliver gas to the second cavity 114 through the two working reversing valves 21, which is equivalent to increasing the diameter of the pipeline, reducing the pressure loss of the gas along the way, and further increasing the gas pressure in the second cavity 114, so that the piston 122 drives the valve disc 121 to move toward the first channel 111 until the first channel 111 is closed. Then, the valve core of the working reversing valve 21 can be switched to the first working position o, so that the second cavity 114 remains closed, and the valve disc 121 is kept in a stationary state, so that the main valve 1 remains in a closed state.

[0027] When the main valve 1 needs to be opened, the valve core of the working reversing valve 21 is switched to the second working position a, the second cavity 114 is connected to the atmosphere, the gas pressure in the second cavity 114 decreases, and the valve flap 121 moves away from the first channel 111 under the push of the gas in the first channel 111, and the main valve 1 is opened. Then, the valve core of one of the working reversing valves 21 is switched back to the first working position o, and the valve core of the other working reversing valve 21 is switched to the third working position b, so that the control gas source 20 only delivers gas to the second cavity 114 through one working reversing valve 21. When the thrust of the piston 122 is balanced with the thrust of the valve flap 121, the distance between the valve flap 121 and the first channel 111 remains unchanged, so that the flow of the main valve 1 remains stable.

[0028] When the flow of the main valve 1 needs to be further increased, the valve core of the working reversing valve 21 is switched to the second working position a, the second cavity 114 is connected to the atmosphere, the gas pressure in the second cavity 114 decreases, and the valve flap 121 moves away from the first channel 111 under the push of the gas in the first channel 111, and the main valve 1 is further opened.

[0029] Of course, in order to achieve more precise flow control, more working reversing valves 21 can be provided to more accurately adjust the opening and closing size of the main valve 1 .

[0030] The working reversing valve 21 may be not only an electromagnetic reversing valve, but also a manual reversing valve or a pneumatic reversing valve to adapt to different application scenarios.

[0031] Embodiment 2 like Figure 2 As shown, eight working reversing valves 21 are provided in the control circuit 2, so as to achieve more precise control of the opening and closing size of the main valve 1, so as to adapt to the occasions where the flow control accuracy of the main valve 1 is required to be high. The eight working reversing valves 21 are divided into two groups, which are fixed to the main valve body 11 in a mechanical connection manner and communicated with the second cavity 114. One group of working reversing valves 21 is communicated with the control gas source 20 through the first communicating vessel 23, and the other group is communicated with the control gas source 20 through the second communicating vessel 24.

[0032] In the second embodiment, if Figure 2 As shown, the main valve 1 further includes a spring 13, one end of the spring 13 is connected to the valve disc 121, and the other end is connected to the main valve body 11. The spring 13 can provide additional thrust for the valve disc 121, reducing the thrust required for the valve disc 121 to move when closing the first channel 111, thereby reducing the air pressure required for the entire control loop 2, and the pneumatic components used in the control loop 2 can select components with lower pressure, thereby reducing the cost of the control loop 2.

[0033] Embodiment 3 As a further improvement of the second embodiment, Figure 3 As shown, eight working reversing valves 21 are connected to the second cavity 114 by a hose, the first communicating vessel 23 connects all the working reversing valves 21 to the second cavity 114, and the second communicating vessel 24 connects all the working reversing valves 21 to the control gas source 20. The control circuit 2 adds a first cut-off valve 25 and a second cut-off valve 26, and connects the second communicating vessel 24 to the first channel 111. The first cut-off valve 25 is connected in series between the second communicating vessel 24 and the first channel 111, and the second cut-off valve 26 is connected in series between the control gas source 20 and the second communicating vessel 24. When the control gas source 20 fails, the airflow of the main pipeline can be introduced into the second cavity 114 as the control gas source 20 to continue to control the main valve 1.

[0034] Embodiment 4 Based on the third embodiment, Figure 4 As shown, the control circuit 2 can also be increased to include a third shutoff valve 27 and a standby reversing valve 28, the third shutoff valve 27 is connected in series between the first communicating vessel 23 and the second cavity 114, and the standby reversing valve 28 has a first gas circuit interface A2, a second gas circuit interface R2, and a third gas circuit interface P2, wherein the first gas circuit interface A2 is connected to an end of the first shutoff valve 25 close to the first channel 111, the third gas circuit interface P2 is connected to an end of the third shutoff valve 27 close to the second cavity 114, and the second gas circuit interface R2 is connected to the atmosphere. The valve core of the standby reversing valve 28 can be switched between the fourth working position a2, the fifth working position o2, and the sixth working position b2, so that different switching ports are connected to each other, thereby connecting or disconnecting the second cavity 114 with the control gas source 20 or the atmosphere. When the control air source 20 fails or the working reversing valve 21 cannot work normally, the control air source 20 can be disconnected from the working reversing valve 21, and the working reversing valve 21 can be disconnected from the second cavity 114, and the standby reversing valve 28 can be used to control the opening and closing of the main valve 1 to improve the reliability of the control system.

[0035] Furthermore, a muffler 29 may be provided on the switch ports for deflation on the standby reversing valve 28 and the working reversing valve 21. The muffler 29 can reduce the noise during deflation and is commonly used in the field of pneumatic control.

[0036] Furthermore, the control loop 2 may also be provided with a pressure sensor 210 and an electric control component 220, all the working reversing valves 21 are electrically connected to the electric control component 220, and the pressure sensor 210 is electrically connected to the electric control component 220, and the pressure sensor 210 is used to monitor the pressure value of the fluid in the second channel 112. The electric control component 220 and the pressure sensor 210 can be used to monitor the pressure value of the fluid in the second channel 112 in real time, and realize the remote closed-loop control of the opening and closing of the main valve 1.

[0037] The pressure sensor 210 may be an analog sensor, a digital sensor, or a pressure relay. Different control circuits may be designed according to different sensor types to achieve a closed-loop control mode.

[0038] Specifically, the electric control component 220 includes a PLC controller and a DC-DC switching power supply, the DC-DC switching power supply is electrically connected to all the working reversing valves 21, and the PLC controller is electrically connected to the DC-DC switching power supply. The PLC controller can realize remote control of the working reversing valve 21, and the DC-DC switching power supply is used to provide a DC control power supply for the electromagnetic reversing valve.

[0039] The present application also provides a control method, including a valve closing action stroke and a valve opening action stroke. The implementation method of the control method is described below in conjunction with the pneumatic stop valve provided in the first embodiment.

[0040] The valve closing action includes the following steps: S101. Determine the flow rate or pressure value of the gas that needs to flow out of the second channel 112, and use this as a basis to determine the opening and closing size of the main valve 1. The flow rate of the gas passing through the main valve 1 is positively correlated with the opening and closing size of the main valve 1. The specific calculation method is fluid mechanics theory, which is irrelevant to the essence of the present invention and is well known to ordinary technicians in this field, and will not be repeated here.

[0041] S102. Determine the number of passages that need to be connected between the control gas source 20 and the second cavity 114, and control the valve cores of the corresponding number of working reversing valves 21 to switch between the first working position, the second working position and the third working position, so that some or all of the working reversing valves 21 connect the gas passage between the control gas source 20 and the second cavity 114.

[0042] For example, when the main valve 1 needs to be closed halfway, the valve core of one of the working reversing valves 21 is switched to the third working position b, and the valve core of the other working reversing valve 21 is switched to the first working position o. At this time, only one working reversing valve 21 is connected from the control air source 20 to the second cavity 114.

[0043] S103. Control the gas source 20 to deliver gas into the second cavity 114, so that the pressure in the second cavity 114 increases, and then pushes the piston 122 to drive the valve flap 121 to move in the direction close to the first channel 111. As the gap between the valve flap 121 and the first channel 111 decreases, the pressure of the gas in the first channel 111 on the valve flap 121 gradually increases until it is balanced with the thrust applied by the piston 122, so that the valve flap 121 stops moving and remains stationary, and the flow of the main valve 1 decreases to a certain value and remains stable.

[0044] Specifically, when the main valve 1 needs to be closed, the valve core of the working reversing valve 21 is switched to the third working position b. At this time, the control gas source 20 can deliver gas to the second cavity 114 through the two working reversing valves 21, which is equivalent to increasing the diameter of the pipeline, reducing the pressure loss of the gas along the way, and further increasing the gas pressure in the second cavity 114, so that the piston 122 drives the valve disc 121 to move toward the first channel 111 until the first channel 111 is closed. Subsequently, the valve cores of the working reversing valves 21 can be switched to the first working position o, so that the second cavity 114 remains closed, and the valve disc 121 is kept in a stationary state, so that the main valve 1 remains in a closed state.

[0045] In particular, the pressure value of the control gas source 20 needs to be determined according to the number of working reversing valves 21, the pressure loss caused by the gas passing through the working reversing valves 21, and the pressure required in the second cavity 114 when the main valve 1 is closed. The specific calculation method is fluid mechanics theory, which is irrelevant to the essence of the present invention and is well known to those skilled in the art, and will not be repeated here.

[0046] The valve opening stroke includes the following steps: S201. Determine the flow rate or pressure value of the gas that needs to flow out from the second channel 112, and determine the opening and closing size of the main valve 1 based on this.

[0047] S202. Control the valve core of some or all of the working reversing valves 21 to switch between the first working position, the second working position and the third working position, so that some or all of the working reversing valves 21 connect the second cavity 114 with the atmosphere, and the gas pressure in the second cavity 114 decreases.

[0048] For example, when the main valve 1 needs to be opened, the valve core of the working reversing valve 21 is switched to the second working position a, the second cavity 114 is connected to the atmosphere, the gas pressure in the second cavity 114 drops, and the valve flap 121 moves away from the first channel 111 under the push of the gas in the first channel 111, and the main valve 1 opens.

[0049] S203 . Control the valve cores of some or all of the working reversing valves 21 to switch between the first working position, the second working position and the third working position again, so that some or all of the working reversing valves 21 are connected to the gas passage between the control gas source 20 and the second cavity 114 .

[0050] S204 . Control the gas source 20 to deliver gas into the second cavity 114 , so that the pressure in the second cavity 114 increases, and then the piston 122 drives the valve flap 121 to stop moving.

[0051] Specifically, the valve core of one of the working reversing valves 21 is switched back to the first working position o, and the valve core of the other working reversing valve 21 is switched to the third working position b, so that the control gas source 20 only delivers gas to the second cavity 114 through one working reversing valve 21. When the thrust exerted on the piston 122 is balanced with the thrust exerted on the valve flap 121, the distance between the valve flap 121 and the first channel 111 remains unchanged, so that the flow of the main valve 1 remains stable.

[0052] When the flow of the main valve 1 needs to be further increased, the valve core of the working reversing valve 21 is switched to the second working position a, the second cavity 114 is connected to the atmosphere, the gas pressure in the second cavity 114 decreases, and the valve flap 121 moves away from the first channel 111 under the push of the gas in the first channel 111, and the main valve 1 is further opened.

[0053] The above control method is an open-loop control method of the pneumatic stop valve provided in the first embodiment of the present application. If the pneumatic stop valve provided in the fourth embodiment of the present application is used as a basis, closed-loop control can be implemented. Specifically, after the corresponding working reversing valve 21 is controlled to connect or disconnect the passage between the control gas source 20 and the second cavity 114, the pressure sensor 210 is used to detect the pressure of the gas in the second channel 112 to determine whether the opening and closing size of the main valve 1 meets the requirements, and then all or part of the working reversing valves 21 are controlled again to perform actions, change the number of passages between the control gas source 20 and the second cavity 114, change the opening and closing size of the main valve 1, and realize closed-loop control.

[0054] This control method can also be set to be automatically executed by a computer program. For example, after the pressure value of the gas in the second channel 112 is set, the program stored in the PLC controller automatically controls the working reversing valve 21 to perform corresponding actions based on the data feedback from the pressure sensor 210, thereby realizing fully automatic control of the pneumatic stop valve.

[0055] Finally: The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A pneumatic stop valve, characterized in that: include: A main valve, comprising a main valve body and a valve stem, wherein the main valve body is provided with a first channel and a second channel which are interconnected, a first cavity is provided at the connection point between the first channel and the second channel, and a second cavity is further provided in the main valve body, one end of the valve stem is provided with a valve flap, and the other end is provided with a piston, the valve flap is accommodated in the first cavity, and the piston is accommodated in the second cavity, and the valve flap can block or open the first channel under the drive of the piston; A control circuit, comprising at least two working reversing valves and a control air source, wherein all the working reversing valves are connected in parallel between the control air source and the second cavity, and each of the working reversing valves has at least three switching ports, which are respectively connected to the second cavity, the control air source and the atmosphere; The valve core of each working reversing valve can be switched between the first working position, the second working position and the third working position, so that different switching ports are connected to each other, thereby connecting or disconnecting the second cavity with the control air source or the atmosphere.

2. A pneumatic stop valve according to claim 1, characterized in that: The control circuit includes eight working reversing valves, and the working reversing valves are three-position three-way electromagnetic reversing valves.

3. A pneumatic stop valve according to claim 1, characterized in that: The control circuit further includes a first communicating vessel and a second communicating vessel, wherein the first communicating vessel is used to connect all the working reversing valves with the second cavity, and the second communicating vessel is used to connect all the working reversing valves with the control gas source.

4. A pneumatic stop valve according to claim 3, characterized in that: The control circuit also includes a first shutoff valve and a second shutoff valve, the second communicating vessel is connected to the first channel, the first shutoff valve is connected in series between the second communicating vessel and the first channel, and the second shutoff valve is connected in series between the control gas source and the second communicating vessel.

5. A pneumatic stop valve according to claim 4, characterized in that: The control circuit further includes a third shutoff valve and a spare reversing valve, wherein the third shutoff valve is connected in series between the first communicating vessel and the second cavity, and the spare reversing valve has at least a first gas path interface, a second gas path interface and a third gas path interface, wherein the first gas path interface is connected to an end of the first shutoff valve close to the first channel, the second gas path interface is connected to an end of the third shutoff valve close to the second cavity, and the third gas path interface is connected to the atmosphere; The valve core of the standby reversing valve can be switched between the fourth working position, the fifth working position and the sixth working position, so that the first gas circuit interface, the second gas circuit interface and the third gas circuit interface are interconnected, and the second cavity is connected or disconnected with the control gas source or the atmosphere.

6. A pneumatic stop valve according to claim 5, characterized in that: A muffler is also provided on the third gas path interface of the standby reversing valve.

7. A pneumatic stop valve according to claim 6, characterized in that: The control circuit also includes a pressure sensor and an electronic control component. All the working reversing valves are electrically connected to the electronic control component. The pressure sensor is electrically connected to the electronic control component. The pressure sensor is used to monitor the pressure value of the gas in the second channel.

8. A pneumatic stop valve according to claim 7, characterized in that: The electric control component includes a PLC controller and a DC-DC switching power supply, the DC-DC switching power supply is electrically connected to all the working reversing valves, and the PLC controller is electrically connected to the DC-DC switching power supply.

9. The pneumatic stop valve according to claim 1, characterized in that: The main valve further comprises a spring, one end of which is connected to the valve disc, and the other end of which is connected to the main valve body.

10. A method for controlling a pneumatic stop valve, characterized in that: Used to control the pneumatic stop valve according to any one of claims 1 to 9, the control method comprising a valve closing action stroke and a valve opening action stroke; The valve closing action stroke comprises the following steps: S101. Determine the flow rate or pressure value of the gas that needs to flow out of the second channel, and determine the size of the opening and closing of the main valve based on this; S102. Controlling part or all of the valve cores of the working reversing valves to switch between the first working position, the second working position and the third working position, so that part or all of the working reversing valves connect the gas passage between the control gas source and the second cavity; S103. The control gas source delivers gas to the second cavity, so that the pressure in the second cavity increases, thereby pushing the piston to drive the valve disc to move toward the first channel; The valve opening action stroke comprises the following steps: S201. Determine the flow rate or pressure value of the gas that needs to flow out of the second channel, and determine the size of the opening and closing of the main valve based on this; S202. Control the valve core of some or all of the working reversing valves to switch between the first working position, the second working position and the third working position, so that some or all of the working reversing valves connect the second cavity with the atmosphere, so that the gas pressure in the second cavity decreases; S203. again controlling the valve core of part or all of the working reversing valves to switch between the first working position, the second working position and the third working position, so that part or all of the working reversing valves connect the gas passage between the control gas source and the second cavity; S204. The control gas source delivers gas to the second cavity to increase the pressure in the second cavity, thereby causing the piston to drive the valve flap to stop moving.

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