CN112066075A - Air circuit for pneumatic actuator - Google Patents

Abstract

A gas circuit for a pneumatic actuator comprises a gas inlet unit, a positioning unit, a valve unit and a pneumatic actuator which are connected in series on a gas source connecting pipeline; the air inlet unit is connected with an air source; the valve unit comprises two pneumatic control valves for respectively supplying air to and from the valve unit; the positioning unit is used for realizing the adjustment of the valve unit and comprises a power-off position-keeping module and a gas-off position-keeping module; the power-off position-keeping module can play a position-keeping role in power failure or power failure; the two ends of the power-off position-keeping module are respectively connected with the air source and the pneumatic control valve; the air-break and position-keeping module can play a position-keeping role when an air source fails or is cut off; one end of the air-break and position-protection module is connected with the air-break and position-protection module, the other end of the air-break and position-protection module is connected between the air inlet unit and the valve unit, and the third end of the air-break and position-protection module is connected with an air source. Therefore, the positioning unit can provide a position-keeping function when power and gas are cut off.

Description

Air circuits for pneumatic actuators

technical field

The invention relates to a pneumatic actuator, in particular to a pneumatic circuit for a pneumatic actuator.

Background technique

Pneumatic actuators are automatic actuators with compressed air as the power source. Through the received signal, the flow of the regulated fluid is directly changed to automate the production process. However, various unexpected situations often occur in the production process, such as power failure or air source failure. At this time, it is necessary to automatically close the air path to the pneumatic actuator and maintain the current valve position opening.

The air circuit of the commonly used pneumatic actuators is shown in Figure 2. To realize the function of three-break position retention and power-off position retention, solenoid valve 01 must be equipped. The protection terminal box 03 needs to be set up to keep the signal in place.

The existing air path used for pneumatic actuators uses a lock valve (position retention valve) to achieve loss of air and position retention, but it has a relatively large impact on the flow capacity of the air path, especially when normal operating conditions require rapid action. , the flow capacity of the retaining valve itself seriously affects the full stroke time. How to quickly realize the loss of air retention is a technical problem that needs to be solved urgently by those skilled in the art.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a pneumatic circuit for a pneumatic actuator that can at least solve the technical problems mentioned in the background art.

The technical solution adopted by the present invention to solve the technical problem is: an air circuit for a pneumatic actuator, comprising an air intake unit, a positioning unit, a valve unit and a pneumatic actuator connected in series on the air source connection pipeline; The air unit is connected to the air source; the valve unit includes two air control valves for gas inlet and outlet respectively; the positioning unit is used to realize the adjustment of the valve unit, including a power-off and gas-cut position-keeping module; the power-off protection The position module can control the action of two air control valves, cut off the compressed air, and play a role in maintaining position when the power fails or is cut off; A pneumatic control valve; the air cut-off and position-keeping module can cut off the compressed air of the air source by evacuating the compressed air and control the action of the two air control valves when the air source fails or the air source is cut off; the One end of the gas-cut position-keeping module is connected to the power-off position-keeping module, the other end of the gas-cut position-keeping module is connected between the air intake unit and the valve unit, and the third end of the gas-cut position-keeping module is connected to the gas source.

The present invention is further arranged as follows: the positioning unit further includes a signal-breaking position-keeping module; the signal-breaking position-keeping module can cut off the compressed air after the signal is cut off to play a position-keeping role; one end of the signal-breaking position-keeping module Connect the air intake unit, and connect two air control valves to the other ends of the air intake unit.

The present invention is further provided as follows: the signal-breaking position maintaining module includes an electric positioner; the electric positioner can cut off the compressed air in the air source to play a position retaining function; the electric positioner can increase or decrease the current by increasing or decreasing the current. Signal to realize the adjustment of the valve; the power-off and position-keeping module includes a solenoid valve; when the power fails or the solenoid valve is powered off, the compressed air at the solenoid valve is emptied through the solenoid valve, and the air control valve is controlled and acted quickly to remove The compressed air in the air source is quickly cut off to maintain the position; the air-cut and position-preserving module includes an air-controlled reversing valve; when the air source fails or the air source is cut off, the air-controlled reversing valve acts, and the air-controlled reversing valve is located at the The compressed air of the air control valve is emptied, and the air control valve is controlled and acted quickly to quickly cut off the compressed air in the air source, so as to maintain the position; one end of the air control reversing valve is connected to the solenoid valve, and the other end is connected to the Between the electrical positioner and the air intake unit, the third end is connected to the air source.

The present invention is further provided as follows: the input signal of the electrical positioner is 4-20mA.

The present invention is further provided as follows: the valve unit may further include two speed control valves on the connecting pipelines for gas inlet and outlet respectively, wherein two ends of one speed control valve are respectively connected to the air control valve and the pneumatic actuator, and the other Two ends of a speed regulating valve are respectively connected with the pneumatic control valve and the pneumatic actuator.

The present invention is further provided as follows: the switching actions of the pneumatic actuator are all driven and performed by the air source.

The present invention is further provided as follows: the gas source connecting pipeline is made of 304 stainless steel.

A further arrangement of the present invention is that: the air intake unit includes a decompression module for stabilizing the gas provided by the gas source, a filter module for filtering the gas, and an oil mist module for atomizing the lubricating oil, which are connected in series.

The present invention is further arranged as follows: the air source is a cylinder, the air source pressure is 0.4MPa, the air control valves are all 2-position 2-air control valves; the air intake unit is an air source triplet.

The beneficial effect of the present invention lies in that, through the power-off and gas-off position-holding module and the gas-off position-holding module of the positioning unit, a gas circuit for the pneumatic actuator with position-holding function can be provided when the power is off and the gas is cut off. Further, through the signal-breaking and position-keeping module of the positioning unit, when the signal is turned off, an air circuit for the pneumatic actuator with position-keeping function can be provided. Moreover, the present invention realizes the rapid action of the valve by using the air-controlled reversing valve and two 2-position 2-air control valves instead of the lock valve (position retaining valve), thereby ensuring the flow capacity.

Description of drawings

FIG. 1 is a schematic diagram illustrating the main components and relative positional relationship of the present invention.

Fig. 2 is a schematic diagram schematically illustrating the main components and relative positional relationship of the air circuit of a commonly used pneumatic actuator.

Detailed ways

In the following description, similar elements are denoted by the same reference numerals, and the directional terms are only used to illustrate the relative positional relationship between the elements, and do not limit the technical scope of the present invention.

As shown in FIG. 1 , the air circuit used in the pneumatic actuator of the present invention includes an air intake unit 1 , a positioning unit, a valve unit and a pneumatic actuator 9 connected in series on the air source connection pipeline. The air source connection pipeline is made of 304 stainless steel.

The air intake unit 1 is connected to an air source, and includes a decompression module, a filter module and an oil mist module connected in series. The decompression module is used to stabilize the gas provided by the gas source, the filter module is used to filter moisture or debris in the gas, and the oil mist module is used to atomize the lubricating oil to facilitate lubricating the moving parts of the body. The structures of the decompression module, the filter module and the oil mist module are not the focus of the improvement of the present invention, and the decompression valve, filter and lubricator in the prior art can be used, so they will not be described in detail. In this embodiment, the air intake unit 1 is an air source triplet of SMC, the model is AC25-N02G-A, and the air source interface is NPT1/4. The air source is a cylinder, and the air source pressure is 0.4MPa.

The valve unit includes two gas control valves 5 and 6 for gas inlet and outlet respectively. In this embodiment, the air control valves 5 and 6 are both 2-position 2-air control valves, and SMC is selected, the model is VNA101-8A, and the air source interface is 1/4.

During specific implementation, in order to adjust the on-off time of the pneumatic actuator, the valve unit may further include two speed regulating valves 7 and 8 respectively on the connecting pipelines for gas inlet and outlet. The two ends of the speed regulating valve 7 are respectively connected to the air control valve 6 and the pneumatic actuator 9 ; the two ends of the speed regulating valve 8 are respectively connected to the air control valve 5 and the pneumatic actuator 9 . In this embodiment, the speed regulating valves 7 and 8 are all selected from SMC, the model is AS2000-02, and the air source interface is 1/4.

The switching actions of the pneumatic actuator 9 are all driven by the air source, that is, double-acting. The pneumatic actuator 9 in this embodiment selects a fork-type double-acting pneumatic actuator from St. Hans.

The positioning unit is used to realize the adjustment of the valve unit, including a signal-breaking position-keeping module, a power-off position-keeping module, and a gas-breaking position-keeping module.

The off-signal keeping module includes an electrical positioner 4 . After the signal fails or the signal is cut off, the electrical positioner 4 can cut off the compressed air in the cylinder to maintain the position. In specific implementation, the input signal of the electrical positioner 4 is 4-20 mA, and the valve is adjusted by increasing or decreasing the current signal. One end of the electrical positioner 4 is connected to the air intake unit 1 , and the other ends thereof are connected to the air control valves 5 and 6 respectively.

In this embodiment, the electrical positioner 4 is selected from ABB, the model is V18345-2020561101, M20×1.5 is the electrical interface, G1/4 is the air source interface, with 4-20mA feedback, with three-stage positioning function, built-in proximity Switch feedback.

The power-off position maintaining module includes a solenoid valve 3 . When the power supply fails or the solenoid valve 3 is powered off, the compressed air at the solenoid valve 3 is evacuated through the solenoid valve 3, and the air control valves 5 and 6 are controlled to move quickly to cut off the compressed air in the cylinder quickly to maintain the position. Wherein, one end of the solenoid valve 3 is connected to the gas-cut and position-holding module, and the other end of the solenoid valve 3 is connected to the air control valves 5 and 6 respectively.

In this embodiment, the solenoid valve 3 is selected from ASCO, the model is SCG551A001MS, the air source interface is NPT1/4, and the power supply is DC24V.

The gas cut-in position module includes a gas-controlled reversing valve 2 . When the air source fails or the air source is cut off, the air control reversing valve 2 is activated, the compressed air at the air control reversing valve 2 is emptied, and the air control valves 5 and 6 are controlled to move quickly to cut off the compressed air in the cylinder quickly. Play the role of security. One end of the air-controlled reversing valve 2 is connected to the solenoid valve 3 , the other end is connected between the electrical positioner 4 and the air intake unit 1 , and the third end is connected to the air source.

In this embodiment, Rotork is selected for the air-controlled reversing valve 2, and the model is YT-520S, wherein the air source interface is NPT1/4, and the input signal is 0.14-0.7MPa.

The following will describe the entire pneumatic control principle for pneumatic actuators.

When the solenoid valve 3 is energized, the air source passes through the air intake unit 1 to the electrical positioner 4, and enters the pneumatic actuator through one of the air control valves and one of the speed control valves, and the gas from the pneumatic actuator passes through the other one. A speed control valve, and the other air control valve to the electric positioner 4. At the same time, part of the gas in the two air control valves will be connected to the air source and the air intake unit 1 via the solenoid valve 3 and the air control reversing valve 2 .

Since the air control reversing valve 2 and two 2-position 2-air control valves 5 and 6 are used in the present invention to replace the original lock valve (position retention valve), compared with the commonly used retention valve, it generally needs to be installed at the inlet of the cylinder. For the outlet position, in the present invention, the air-controlled reversing valve can be farther away from the cylinder and closer to the main air source, and the reaction time of degassing action is faster, especially for occasions requiring rapid response to accident conditions, which is safer and more advantageous. In addition, compared with the position retaining valve of the same specification, the 2-position 2-air control valve has a larger effective cross-sectional area and better flow capacity, and the diameter of the 2-position 2-air control valve can be larger than that of the position retaining valve. Therefore, the flow capacity of the gas path will be better under the condition of maintaining the position in the same way.

Moreover, because in the present invention, a positioner with its own power-off, signal-break, and gas-cut-off position is used instead of the traditional positioner plus a protection terminal box, the function of signal-break position and position-keeping can also be realized under the condition of reducing accessories; and the new The function of maintaining the position after gas cut is added, and it forms a redundant function of maintaining the position after cutting off the gas with two 2-position two-air control valves, which is more secure. for safety.

Therefore, through the power-off and air-cut position-holding module of the positioning unit, when power is cut off and the gas is cut off, a pneumatic circuit for a pneumatic actuator with a position-holding function can be provided. Further, through the signal-breaking and position-keeping module of the positioning unit, when the signal is turned off, the air circuit for the pneumatic actuator can be provided with a position-keeping function, which can indeed achieve the purpose of the present invention.

The above are only preferred embodiments of the present invention, and cannot limit the technical scope of the present invention, but any simple equivalent changes made in accordance with the claims and descriptions of the present invention belong to the scope of the present invention .

Claims (9)

1. An air passage for a pneumatic actuator; the method is characterized in that: the pneumatic control system comprises an air inlet unit, a positioning unit, a valve unit and a pneumatic actuating mechanism which are connected in series on an air source connecting pipeline;

the air inlet unit is connected with an air source;

the valve unit comprises two pneumatic control valves for respectively supplying air to and from the valve unit;

the positioning unit is used for realizing the adjustment of the valve unit and comprises a power-off position-keeping module and a gas-off position-keeping module;

the power-off position-keeping module can control the two air control valves to act to cut off compressed air to play a position-keeping role when a power supply fails or is powered off; one end of the power-off position-keeping module is connected with the air source, and the other end of the power-off position-keeping module is respectively connected with two air control valves;

the air-break and position-keeping module can cut off the compressed air of the air source by emptying the compressed air and controlling the two air control valves to act when the air source fails or is cut off, thereby playing a position-keeping role; one end of the air-break and position-protection module is connected with the air-break and position-protection module, the other end of the air-break and position-protection module is connected between the air inlet unit and the valve unit, and the third end of the air-break and position-protection module is connected with an air source.

2. The pneumatic circuit for a pneumatic actuator of claim 1, wherein: the positioning unit also comprises a signal-breaking bit-retaining module; the signal interruption position-keeping module can cut off compressed air after a signal is interrupted, so that a position-keeping effect is achieved; one end of the signal interruption position protection module is connected with the air inlet unit, and the other two ends of the signal interruption position protection module are respectively connected with two air control valves.

3. The pneumatic circuit for a pneumatic actuator of claim 2, wherein: the signal interruption position-keeping module comprises an electric positioner; the electric positioner can cut off compressed air in an air source to play a role in position protection; the electrical positioner effects adjustment of the valve by increasing or decreasing the current signal; the power-off position-keeping module comprises an electromagnetic valve; when the power supply fails or the electromagnetic valve is powered off, compressed air at the electromagnetic valve is exhausted through the electromagnetic valve, the pneumatic control valve is controlled to act quickly, and the compressed air in the air source is cut off quickly to play a role in position retention; the air-break position-keeping module comprises an air control reversing valve; when the air source is in failure or is cut off, the pneumatic control reversing valve acts, compressed air at the pneumatic control reversing valve is emptied, the pneumatic control valve is controlled to act quickly, and the compressed air in the air source is cut off quickly to play a role in position retention; one end of the pneumatic control reversing valve is connected with the electromagnetic valve, the other end of the pneumatic control reversing valve is connected between the electric positioner and the air inlet unit, and the third end of the pneumatic control reversing valve is connected with an air source.

4. The pneumatic circuit for a pneumatic actuator of claim 3, wherein: the input signal of the electrical locator is 4-20 mA.

5. The pneumatic circuit for a pneumatic actuator of claim 1, wherein: the valve unit can also comprise two speed regulating valves which are respectively arranged on the connecting pipelines for gas inlet and gas outlet, wherein the two ends of one speed regulating valve are respectively connected with the pneumatic control valve and the pneumatic actuating mechanism, and the two ends of the other speed regulating valve are respectively connected with the pneumatic control valve and the pneumatic actuating mechanism.

6. The pneumatic circuit for a pneumatic actuator of claim 1, wherein: the opening and closing actions of the pneumatic actuating mechanism are driven and executed by an air source.

7. The pneumatic circuit for a pneumatic actuator according to any one of claims 1 to 6, wherein: the air source connecting pipeline is made of 304 stainless steel.

8. The pneumatic circuit for a pneumatic actuator according to any one of claims 1 to 6, wherein: the air inlet unit comprises a pressure reduction module, a filtering module and an oil mist module, wherein the pressure reduction module is used for stabilizing the pressure of gas provided by a gas source, the filtering module is used for filtering the gas, and the oil mist module is used for atomizing lubricating oil.

9. The pneumatic circuit for a pneumatic actuator according to any one of claims 1 to 6, wherein: the air source is an air cylinder, and the pressure of the air source is 0.4 MPa; the pneumatic control valves are all 2-position 2-ventilation control valves; the air inlet unit is an air source triple piece.

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