Features and definitions of pneumatic diaphragm control valves

The pneumatic diaphragm regulating valve has the advantages of compact structure, lightweight, sensitive action, fluid type, less pressure drop loss, large valve capacity, accurate flow characteristics, convenient assembly, and disassembly. It is widely used to precisely control media such as gas, liquid, and steam. Process parameters such as pressure, flow, temperature, and liquid level are kept at a given value.

List of content for this article：

1.The pneumatic diaphragm regulating valve's advantages.

2.The characteristics of the pneumatic diaphragm regulating valve.

The characteristics of the pneumatic diaphragm regulating valve are as follows:

1. The input and output characteristics of the actuator of the pneumatic diaphragm regulating valve exhibit a linear relationship, which is linear between the output displacement and the input signal pressure. The output displacement is called the stroke and is displayed by the stroke display panel. Some reaction actuators also have a valve position display on the top of the bellows for displaying the valve position. The strokes of the domestic pneumatic diaphragm regulating valve actuators are available in six sizes: 10mm, 16mm, 25mm, 40mm, 60mm, and 100mm.

2. The effective area of the diaphragm of the actuator is proportional to the thrust. The larger the effective area, the greater the thrust of the actuator.

3. The structure of the positive and negative actuators is basically the same, consisting of the upper membrane cover, the lower membrane cover, the membrane, the push rod, the spring, the adjusting member, the bracket and the stroke display panel.

4. The main difference between the structure of the positive and negative actuators is that the input signal of the reaction actuator is in the lower part of the bellows, and the push rod is also in the lower part. Because of the good sealing of the film piece, it is not necessary to seal at the valve stem.

5. The initial force of the spring can be changed by adjusting the adjustment member to change the thrust of the actuator.

6. The pneumatic diaphragm regulating valve can be added with a self-locking device to realize self-locking and retaining of the control valve.

7. Valve positioner can be added to realize valve position detection and feedback to improve control performance.

8. The pneumatic diaphragm regulating valve can be added with a displacement conversion device to convert the linear displacement into an angular displacement for rotating the valve body.

9. The pneumatic diaphragm regulating valve can be added with a handwheel mechanism. When the automatic control fails, the handwheel is used for degrading operation to improve system reliability.