What are the main causes of pneumatic control valve,?

What are the main causes of pneumatic control valve,? When in the process of using this product, there will be a failure, at this time, not according to their wishes to repair, but targeted to adjust again to find the reason. The general failure is what? （ A) Pneumatic control valve action. No signal, no air. Gas source is not open, paying due to air water freezes in winter, cause the clogging in duct blockage or filter, pressure reducing valve failure, (3) compressor fault; (4) air duct leakage. Air supply, no signal. 1) regulator malfunction; (3) locator corrugated pipe leakage; (4) adjust the retinal damage. The locator without air. (1) filter clogging; (2) reducing valve fault (3) pipe leakage or jam. Locator has a gas source, no output. Locator orifice clogging. There are signals, no action. (1) the valve core loss, (2) the valve core and the social or stuck with the valve seat; (3) stem bend or break; (4) seat valve core to freeze or focal piece of dirt; (5) spring actuator due to long-term need not rust. （ 2) The pneumatic - valve action is not stable. Air pressure is not stable. (1) compressor capacity is too small; (2) the pressure reducing valve failure. Pressure signal is not stable. (1) the control system of time constant ( T＝RC） Not appropriate; (2) the controller output is not stable. Stable air pressure, pressure is stable signal, but the action of pneumatic control valve is still unstable. (1) the locator produets amplifier of ball valve and the dirt of lax, special gas consumption increase would produce output volatility; (2) locator nozzle baffle amplifier of parallel, shutter not nozzle; (3) the output pipe, line leak; (4) actuators rigidity is too small; (5) motion of the valve stem friction resistance is big, with the contact parts are blocking phenomenon. （ 3) The pneumatic - valve vibration. Pneumatic control valve in He Kaidu under vibration. (1) to support the instability; (2) there is vibration source near; (3) the valve core and bushing wear. The pneumatic - valve full close position near the end of the vibration. 1) pneumatic - valve to choose large, often used in the small open degrees; (2) the flow direction of medium single-seat valve to close in the opposite direction.