Function principle of air close pneumatic diaphragm control valve
Time: April 10, 2020 15:36:20 Source: Yonglong Valve Reading: zero second
Function principle of air close pneumatic diaphragm control valve
In the production process, if the regulating valve is used too long, the stroke will be inaccurate. There is always a large error at a certain position. The stroke is 0-100%. Select the maximum point for adjustment, which is 0, 25, 50, 75, 100, and all are expressed in percentage. Especially for mechanical valve positioners, it is necessary to make clear where the two manual parts of the zero position adjustment and span adjustment inside the positioner are.
Operating principle of air close pneumatic diaphragm regulating valve:
For the positive acting valve positioner, the controller output signal is 4-20mA. At 4mA, the corresponding gas signal is 20Kpa, and the control valve is fully opened. When 20mA, the corresponding gas signal is 100Kpa, and the control valve is fully closed. The pneumatic diaphragm air chamber is provided with air source, and the six spring springs covered by the downward pressure diaphragm push the valve stem downward. The valve stem is connected with the valve core, and the valve core is installed in the positive direction, so the air source is the valve moving toward the closed position. Therefore, it is called an air shutoff valve. Fault open means that when the gas supply is interrupted due to construction or corrosion of the gas pipe, the valve will reset under the reaction force of the spring, and the valve will be in the fully open position again.
If the pneumatic control valve of air opening type is taken as an example, the adjustment shall be carried out.
The first step; For zero adjustment, the control room or signal generator shall be given 4mA, and the regulating valve shall be fully closed. If it cannot be fully closed, zero adjustment shall be carried out. After zero adjustment, directly adjust 50% of the point, and adjust the span with the difference. At the same time, note that the feedback rod and valve rod should be vertical. After adjustment, adjust the 100% point. After adjustment, repeatedly adjust from the five points between 0-100% until the opening is accurate.
Conclusion; From mechanical positioner to intelligent positioner. From the perspective of science and technology, the rapid development of science and technology has reduced the labor intensity of front-line maintenance personnel. Personally, if you want to exercise your hands-on ability and learn technology, mechanical locators are the best, especially for new instrument personnel. The intelligent positioner can understand the words in the manual, and it is OK to move your finger. The zero adjustment, range adjustment and stroke adjustment are all automatically adjusted, as long as you wait foolishly for it to finish its own play, and then clear up the scene and leave. For the mechanical type, many parts need to be dismantled and repaired and installed by yourself, which can improve the hands-on ability and make more impression on its internal structure.
Whether it is intelligent or mechanical, it plays a leading role in the entire automated production process. Once "problems" occur, there is no way to regulate, and automatic control will lose its significance.
Emergency shut-off valve -Regulating valve - diaphragm regulating valve - pneumatic regulating valve - electric regulating valve - pneumatic single seat regulating valve - pneumatic diaphragm sleeve regulating valve - pneumatic diaphragm single seat regulating valve - pneumatic sleeve regulating valve - Shanghai Yonglong Valve Factory
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