Causes and solutions of internal leakage of pneumatic control valve
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Release Time：2018-01-19
Pneumatic control valve has been more and more widely used in various industrial control systems because of its high control accuracy and convenient installation and debugging. However, in the process of use, there are also some problems, that is, the internal leakage of the valve. Common causes and solutions of internal leakage of pneumatic control valves. 1. The zero position setting of the actuator is not accurate and the valve is not fully closed. Adjustment methods: 1) close the valve manually (it must be confirmed that it has been completely closed);2) Close the valve manually with force, subject to a little effort. 3) Screw back (valve opening direction) half a turn; 4) Then adjust the limit. 2, the valve is down
Pneumatic control valve has been more and more widely used in various industrial control systems because of its high control accuracy and convenient installation and debugging. However, in the process of use, there are also some problems, that is, the internal leakage of the valve. Common causes and solutions of internal leakage of pneumatic control valves.
1. The zero position setting of the actuator is not accurate and the valve is not fully closed.
Adjustment method: 1) close the valve manually (it must be confirmed that it has been completely closed);22) Manually close the valve with force, subject to a slight force that cannot be screwed;32) Screw back half a circle (valve opening direction);4) Then adjust the limit.
2. The valve is pushed down and closed. The thrust of the actuator is not large enough. When there is no pressure, it is easy to reach the full closing position when debugging. When there is a downward thrust, the upward thrust of the liquid cannot be overcome, so it is not closed. Solution: replace the large thrust of the actuator, or changed to a balanced spool to reduce the media imbalance force.
3. Internal leakage caused by manufacturing quality of pneumatic control valve
Valve manufacturers in the production process of the valve material, processing technology, assembly technology and other control is not strict, resulting in the sealing surface grinding unqualified, the pitting, trachoma and other defects of the product is not completely eliminated, resulting in the pneumatic control valve leakage. Solution: rework the sealing surface.
4. The control part of the pneumatic control valve affects the internal leakage of the valve
The traditional control mode of pneumatic control valve is through the valve limit switch, over torque switch and other mechanical control mode, because these control components are affected by the ambient temperature, pressure and humidity, resulting in valve positioning misalignment, spring fatigue, uneven thermal expansion coefficient and other objective factors, resulting in internal leakage of pneumatic control valve. Solution: Re-adjust the limit.
5. Internal leakage caused by debugging problems of pneumatic control valve
Affected by the processing and assembly process, pneumatic control valves generally have the phenomenon that they cannot be opened pneumatically after manual closure,
6, type selection error caused by the valve cavitation corrosion caused by the internal leakage of pneumatic control valve
Different uses of pneumatic valves have different specific technical requirements, according to the system process to a reasonable choice of pneumatic control valve is essential. Solution: process improvement, selection of multi-stage buck or sleeve control valve.
7. Internal leakage caused by medium erosion and aging of pneumatic control valve
Pneumatic control valve after a certain period of time to adjust the operation, due to the valve cavitation and medium erosion, valve core and valve seat wear, internal components aging and other reasons, there will be pneumatic control valve stroke is too large, pneumatic control valve closed lax phenomenon, resulting in pneumatic control valve leakage becomes larger, with the passage of time, pneumatic control valve leakage phenomenon will become more and more serious. Solution: re-adjust the actuator, and regular maintenance, correction can be.
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