A single-control-line dual-pneumatic-valve control system

Abstract

This utility model discloses a single-control-line dual-pneumatic-valve control system, including a main pneumatic valve, a second pneumatic valve, a cylinder, and a control line. The main pneumatic valve is connected to the control line, and its bypass channel is connected to the second pneumatic valve through the cylinder. When the control line controls the main pneumatic valve to close, compressed air pushes the second pneumatic valve to open through the bypass channel and the cylinder; when the main pneumatic valve opens, the bypass channel closes, and the second pneumatic valve closes due to pressure loss. This system achieves dual-valve linkage control through a single line, which can be widely used in the field of chemical automation, achieving the goals of reducing the number of control lines, reducing wiring costs, and improving system reliability. This patent is based on the design of a mother liquor dosing pipeline that can implement an automatic backsweep system, realizing the function of automatically opening the second pneumatic valve to backsweep the pipeline after the mother liquor dosing is completed and closing the main pneumatic valve, and automatically closing the second pneumatic valve when the main start valve for mother liquor addition is opened.

Description

Technical Field

[0001] This utility model relates to the field of pneumatic control technology, specifically a control system that enables the linkage switching of two pneumatic valves through a single control line. Background Technology

[0002] In existing pneumatic control systems, each pneumatic valve requires an independent control line, resulting in the following drawbacks in multi-valve systems: The wiring is complex: n valves require n control lines, and the cable cost increases with n². High failure rate: The circuit has many connection points, which are prone to failure due to wear and moisture. Maintenance difficulties: Multiple wiring layouts increase the difficulty of installation and maintenance. For example, in a certain chemical production process, the mother liquor dosing pipeline involves two pneumatic valves, requiring two control lines. However, complex equipment can have dozens of valves, and wiring costs account for more than 20% of the total system cost. Therefore, there is an urgent need for a pneumatic valve control solution that simplifies the number of control lines. Utility Model Content The purpose of this invention is to overcome the above-mentioned shortcomings and provide a single-control-line dual-pneumatic-valve control system. Through structural innovation, the number of control lines is reduced, system complexity and cost are lowered, and reliability is improved.

[0003] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a single-control-line dual-pneumatic-valve control system, comprising a main pneumatic valve, a second pneumatic valve, a cylinder, and a control line; the control end of the main pneumatic valve is connected to the control line, and the inlet end is connected to a compressed air source; the main pneumatic valve is provided with a bypass channel, which is connected to the inlet of the cylinder through a pipe, and the outlet of the cylinder is connected to the control end of the second pneumatic valve; the inlet end of the second pneumatic valve is connected to a compressed air load pipeline. Preferably, the main pneumatic valve is a two-position five-way solenoid valve, and its bypass channel is connected to the one-way valve inlet of the cylinder through a pipeline. When the main pneumatic valve is closed, the one-way valve is open, and when the main pneumatic valve is open, the one-way valve is closed. Preferably, the cylinder is a double-acting cylinder, and its piston stroke matches the valve core opening displacement of the second pneumatic valve.

[0004] Preferably, the one-way valve is a spring-loaded one-way valve with an opening pressure of 0.1-0.2 MPa and a closing pressure difference of no more than 0.05 MPa.

[0005] Preferably, the inner wall of the cylinder barrel is provided with a wear-resistant coating, which is a polytetrafluoroethylene coating with a thickness of 0.05-0.1 mm.

[0006] Preferably, it also includes a pressure sensor, which is installed in the air inlet pipe of the second pneumatic valve to detect the real-time pressure of the load pipeline and output an electrical signal.

[0007] Preferably, a filter is provided on the connecting pipe between the main pneumatic valve and the compressed air source, the filter having a filtration accuracy of not less than 5μm and a built-in automatic drain valve.

[0008] The beneficial effects of this utility model are as follows: This utility model provides a single control line dual pneumatic valve control system, which reduces the number of control lines, lowers system complexity and cost, and improves reliability through structural innovation. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the structure of this utility model.

[0010] In the above attached diagram: 1. Main pneumatic valve; 101. Bypass channel; 2. Second pneumatic valve; 3. Cylinder; 4. Control line; 5. Pressure sensor; 6. Filter. Detailed Implementation

[0011] To enable those skilled in the art to better understand the technical solution of this utility model, the preferred embodiments of this utility model are described below in conjunction with specific examples. However, it should be understood that the accompanying drawings are for illustrative purposes only and should not be construed as limiting this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable for those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. The positional relationships described in the drawings are for illustrative purposes only and should not be construed as limiting this patent.

[0012] like Figure 1 As shown, a single-control-line dual-pneumatic-valve control system includes a main pneumatic valve 1, a second pneumatic valve 2, a cylinder 3, and a control line 4. The control end of the main pneumatic valve 1 is connected to the control line 4, and the air inlet end is connected to a compressed air source. The main pneumatic valve 1 is provided with a bypass channel 101, which is connected to the air inlet of the cylinder 3 through a pipe. The cylinder 3 and the second pneumatic valve 2 are an integral structure, consisting of a valve body and a cylinder 3. Compressed air is supplied through the cylinder bypass pipe of the first pneumatic valve 1 to act on the cylinder 3 of the second pneumatic valve 2, thereby realizing the opening and closing of the second pneumatic valve 2. The cylinder 3 is connected to the valve body of the second pneumatic valve 2, and the valve body is driven to move by the movement of the valve core of the cylinder 3.

[0013] The above embodiments require only one control line to complete the logic control of the dual valves, reducing the amount of consumables such as wires and terminals, and are especially suitable for long-distance control scenarios, significantly reducing wiring and construction costs.

[0014] In some embodiments, the main pneumatic valve 1 is a two-position five-way solenoid valve, and its bypass channel 101 is connected to the one-way valve inlet of the cylinder 3 through a pipeline. When the main pneumatic valve 1 is closed, the one-way valve is open, and when the main pneumatic valve 1 is open, the one-way valve is closed. In some embodiments, the cylinder 3 is a double-acting cylinder, and its piston stroke is matched with the valve core opening displacement of the second pneumatic valve 2. In some embodiments, the check valve is a spring-loaded check valve with an opening pressure of 0.1-0.2 MPa and a closing pressure difference of no more than 0.05 MPa. The design of the check valve's opening and closing pressure differences ensures that the cylinder operates only within a stable pressure range, preventing malfunctions of the second pneumatic valve caused by small fluctuations in the air source pressure (such as pressure fluctuations caused by the start-up and shutdown of the air compressor), thus ensuring the safety and stability of the air supply to the load pipeline.

[0015] In some embodiments, the inner wall of the cylinder 3 is provided with a wear-resistant coating, which is a polytetrafluoroethylene (PTFE) coating with a thickness of 0.05-0.1 mm. The PTFE coating on the inner wall of the cylinder has excellent wear resistance and self-lubricating properties, which can reduce mechanical wear during piston reciprocating motion, avoid air leakage caused by scratches on the inner wall of the cylinder, and extend the service life of the cylinder; at the same time, it reduces piston movement resistance and ensures stable power when the cylinder pushes the second pneumatic valve.

[0016] In some preferred embodiments, a pressure sensor 5 is also included, which is installed in the air inlet pipe of the second pneumatic valve 2 to detect the real-time pressure of the load pipeline and output an electrical signal.

[0017] In the above embodiment, the pressure sensor 5 at the air inlet of the second pneumatic valve can detect the load pipeline pressure in real time and output an electrical signal, which facilitates the subsequent system (such as PLC) to adjust the action of the main pneumatic valve according to the pressure data (such as closing the main valve in advance when the load pressure is too high to avoid the second valve from being over-opened), forming a closed-loop control of "detection-feedback-adjustment" to prevent over-pressure or under-pressure in the load pipeline.

[0018] In some embodiments, a filter 6 is provided on the connecting pipe between the main pneumatic valve 1 and the compressed air source. The filter 6 has a filtration accuracy of not less than 5μm and a built-in automatic drain valve.

[0019] When using it, control it by following these steps: S1. A closing signal is sent to the main pneumatic valve 1 through the control line 4. The main pneumatic valve 1 closes the main channel. Compressed air enters the cylinder 3 through the bypass channel 101. The cylinder 3 pushes the piston to move, thereby driving the valve body of the second pneumatic valve to move. S2. An opening signal is sent to the main pneumatic valve 1 via control line 4. The main pneumatic valve 1 opens the main channel, the bypass channel 101 closes, the cylinder 3 is depressurized, and the second pneumatic valve 2 closes due to pressure loss.

[0020] In applications, such as adding mother liquor in a sodium hypophosphite reaction, firstly, after the sodium hypophosphite is discharged into the discharge tank, when mother liquor needs to be added to the discharge tank, the operator controls the DCS control system to send an "open" command to the main pneumatic valve. Compressed air from pipeline 1 is supplied to the main pneumatic valve 1 to open it and add a certain amount of mother liquor to the discharge tank. When the amount of mother liquor added reaches the set value, the system automatically closes the main pneumatic valve 1. At this time, the compressed air controlling the main pneumatic valve 1 is transported to the second pneumatic valve 2 through the bypass. The control cylinder 3 pushes the piston to open the second pneumatic valve 2, and the second compressed air pipeline back-swept to the mother liquor pipeline through the second pneumatic valve 2.

[0021] When mother liquor needs to be added again, the operator issues the "open" command to the main pneumatic valve 1 of the system again. Compressed air is supplied to the main pneumatic valve 1 through the No. 1 compressed air pipeline, which opens the main pneumatic valve 1. The bypass channel 101 of the main pneumatic valve 1 is closed, the cylinder has no compressed air supply, the piston resets and closes the second pneumatic valve 2, cutting off the backsweep route, so as to continue adding mother liquor and achieve the purpose of circulation control.

[0022] The above embodiments are merely preferred technical solutions of this utility model and should not be considered as limitations on this utility model. The embodiments and features in these embodiments can be arbitrarily combined without conflict. However, under conditions with high safety and process requirements, these embodiments cannot be used because they cannot provide the on / off state of the second pneumatic valve. The protection scope of this utility model should be the technical solution described in the claims, including equivalent substitutions of the technical features described in the claims. That is, equivalent substitutions and improvements within this scope are also within the protection scope of this utility model.

Claims

1. A single control line dual pneumatic valve control system, characterized by: It includes a main pneumatic valve (1), a second pneumatic valve (2), a cylinder (3) and a control line (4); the control end of the main pneumatic valve (1) is connected to the control line (4), and the air inlet end is connected to a compressed air source; the main pneumatic valve (1) is provided with a bypass channel (101), the bypass channel (101) is connected to the air inlet of the cylinder (3) through a pipe, and the air outlet of the cylinder (3) is connected to the control end of the second pneumatic valve (2); the air inlet end of the second pneumatic valve (2) is connected to the compressed air load pipeline.

2. A single control line dual pneumatic valve control system as claimed in claim 1, wherein: The main pneumatic valve (1) is a two-position five-way solenoid valve. Its bypass channel (101) is connected to the one-way valve inlet of the cylinder (3) through a pipeline. When the main pneumatic valve (1) is closed, the one-way valve is open. When the main pneumatic valve (1) is open, the one-way valve is closed.

3. A single control line dual pneumatic valve control system as defined in claim 1, wherein: The cylinder (3) is a double-acting cylinder, and its piston stroke is matched with the valve core opening displacement of the second pneumatic valve (2).

4. The system of claim 2, wherein: The check valve is a spring-loaded check valve with an opening pressure of 0.1-0.2 MPa and a closing pressure difference of no more than 0.05 MPa.

5. A single control line dual pneumatic valve control system as defined in claim 3, wherein: The cylinder (3) has a wear-resistant coating on its inner wall. The wear-resistant coating is a polytetrafluoroethylene coating with a thickness of 0.05-0.1 mm.

6. A single control line dual pneumatic valve control system as defined in claim 1, wherein: It also includes a pressure sensor (5), which is installed on the air inlet pipe of the second pneumatic valve (2) to detect the real-time pressure of the load pipeline and output an electrical signal.

7. A single control line dual pneumatic valve control system as defined in claim 1, wherein: A filter (6) is provided on the connecting pipe between the main pneumatic valve (1) and the compressed air source. The filter (6) has a filtration accuracy of not less than 5μm and a built-in automatic drain valve.

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