Pneumatic valve positioner fault reason and preventive measures

Pneumatic regulator valve in the application will use a locator, using the locator can be divided into ordinary locator and intelligent positioner.
ordinary locator by mechanical force balance principle of work, namely the nozzle baffle technology, mainly exist the following fault types:
( 1) Due to adopt mechanical force balance principle of work, the more moving parts, easily influenced by temperature, the influence of vibration, cause the volatility of the pneumatic control valve;
　　( 2) The nozzle baffle technology, as a result of nozzle hole is very small, easy to be dust or diaphragm valve clean air blocking, locator is not working;
　　( 3) Using force balance principle, the elastic coefficient of spring under the bad scene change, causing the deterioration of pneumatic control valve nonlinear lead to control the quality. The intelligent positioner by microprocessor, its working principle and common locator is very different. Given value and actual value is relatively pure electric signals, is no longer force balance.
pneumatic regulator valve in the application will use a locator, using the locator can be divided into ordinary locator and intelligent positioner. These valves require stationary at a particular location, bottom valve only an emergency occurs, only need action in a reliable way. For a long time to stay in a position to make electrical converter is out of control to the risk of small signal not action.
in addition for the valve position sensing potentiometer because working in the field of small signal caused resistance to change is not action, the danger of large signal full open. So in order to ensure the reliability and availability of the intelligent positioner, these must be tested frequently.