Pneumatic Valves Manufacturers

The pneumatic valve is mainly composed of air cylinder (pneumatic actuator) and valve body. For different control systems, the corresponding valve positioner, annunciator, electromagnetic reversing valve and air source pressure regulating filter will be assembled again. In the automation application, the demand for pneumatic valves will be higher and higher

Pneumatic valve is a valve driven by compressed air. It can be used to control the flow of various types of fluids such as air, water, steam, various corrosive media, mud, oil, liquid metal and radioactive media. Common pneumatic valves include pneumatic ball valve, pneumatic butterfly valve, pneumatic diaphragm valve and pneumatic pipe clamp valve.

The pneumatic valve is mainly composed of air cylinder (pneumatic actuator) and valve body. For different control systems, the corresponding valve positioner, annunciator, electromagnetic reversing valve and air source pressure regulating filter will be assembled again. In the automation application, the demand for pneumatic valves will be higher and higher

The compressed air is used to drive the movement of multiple groups of combined pneumatic pistons in the actuator, and the force is transmitted to the beam and the inner curved track to drive the air core spindle to rotate. The compressed air disk is transmitted to each cylinder, and the air inlet and outlet positions are changed to change the rotation direction of the spindle. According to the requirements of the rotation torque required by the load (valve), the number of cylinder combinations can be adjusted to drive the load (valve) to work.

The two position five way solenoid valve is usually used in combination with the double acting pneumatic actuator. The two positions are controllable in two positions: on-off. The five way solenoid valve has five channels for ventilation, one of which is connected to the air source, two are connected to the inlet and outlet of the external air chamber of the double acting cylinder, and two are connected to the inlet and outlet of the internal air chamber. The specific working principle can refer to the working principle of the double acting pneumatic actuator. As there are more and more control methods and means, there are many methods used to control pneumatic actuators in actual industrial production and industrial control, including the following.

The intelligent display instrument is used to monitor the working state of the valve and control the operation of the valve during the execution period. It monitors the working state of the valve through two position sensors, judges whether the valve is in the open or closed state, records the number of the valve switch through programming, and has two 4-20mA outputs corresponding to the valve opening and two normally open and normally closed output contacts. Through these output signals, the switching action of the valve is controlled.

Control system

PLC is more and more widely used in the control system. Since this scheme is developed on OMRON PLC, Omron PLC is introduced.

Hardware composition: 1 computer, 1 set of PLC (including CPU, I / O module, id212, oc224 and ad003 module), 2 relays, 2 solenoid valves and 1 pneumatic valve actuator.

Debugging method

Pneumatic valve positioner is one of the most important pneumatic accessories of pneumatic control valve, which can receive control signals and accurately position the valve stroke.

Function of pneumatic valve positioner: the pneumatic valve positioner and the pneumatic actuator jointly constitute an automatic control unit and various control valves. After commissioning and installation, they are combined into a pneumatic control valve. Pneumatic valve positioners are used in various industrial automation and process control fields.

When the pneumatic control valve leaves the factory, both the positioner and the control valve have been calibrated. However, after the valve is installed on the pipeline, it often needs to be calibrated again. The conventional calibration method is: calibrate 5 points, i.e. 4mA, 8Ma, 12mA, 16mA, 20mA. At 12mA, the feedback rod of the positioner is at the horizontal position. For other groups of signals, the valve position should be at 0, 25%, 75%, and 100% of the stroke, and the rotation angle of the feedback rod should be less than plus or minus 45 degrees. The deviation of zero point and full scale can be corrected by adjusting the corresponding screws separately. Under normal circumstances, if the valve stroke and the given signal correspond one-to-one, the calibration is completed.

One of the main problems when the valve is closed is how to achieve the full load of the valve seat to close the valve tightly. The usual method is to calibrate the valve so that the closing parts (such as valve plug, diaphragm, valve plate, etc.) are positioned just on the valve seat, rather than confirming whether the closing parts are completely against the valve seat. In order to maintain the design leakage and avoid corrosion of the sealing surface, an appropriate sealing load must be designed.

Single acting pneumatic actuators are usually of thin film design. With this design, the spring used can reduce the load of the valve seat and can also bear the full closing pressure. A typical double acting pneumatic actuator uses a piston design. With this design, unlike the membrane design, the supply pressure does not need to be limited. In order to achieve a high closing pressure, the full load supply pressure can be applied. For piston design, the higher the pressure, the better the stability and control sensitivity of the valve.