1. The valve positioner has signal input, but no output pressure signal
(1) electric / gas positioner, armature and coil between the foreign body.
(2) constant throttle blockage.
(3) nozzle baffle with bad or nozzle baffle damage.
(4) Damage of the diaphragm (metal diaphragm or rubber diaphragm) in the amplifier.
(5) Incorrect airway connection (including amplifier).
(6) electric / gas positioner input signal line positive and negative reverse.
(7) The diode inside the input terminal of the positioner is open or poorly connected.
(8) the size of the air pressure does not meet the requirements.
(9) Amplifier Excessive value for air consumption.
(10) Electrical / gas positioner The mounting of the magnet is different.
(11) amplifier preload is overweight.
(12) Slip valve in the spool valve is stuck by foreign matter.
(13) "Manual / Auto" switch position is not right (non-manual position and non-automatic position).
(14) electrical / gas positioner input electrical signal short circuit.
(15) balanced spring installation, debugging is not good.
2. The positioner is not linear
(1) Feedback cam or spring selection is not appropriate.
(2) feedback mechanism is not installed well.
(3) Incorrect feedback cam or spring installation.
(4) Nozzles or baffles are contaminated.
(5) Slip valve type amplifier within the slide valve and its contact surface friction phenomenon.
(6) back pressure with a slight leakage phenomenon.
(7) The machine is improperly installed.
(8) feedback connection face control valve card phenomenon.
3. No input signal, the positioner has output pressure
(1) The nozzle is clogged.
(2) the amplifier into the ball valve contamination caused by the card is not dead or sealing surface damage.
(3) The diameter of the constant orifice is larger than the rated diameter of the nozzle diameter.
(4) There is a problem with the connection of the amplifier boards.
(5) the amplifier metal diaphragm deformation or poor installation, resulting in the valve stem will enter the ball valve top open (for preload is not adjustable amplifier).
(6) The baffle has been covered by the nozzle.
4. Stroke is insufficient (the positioner output pressure does not reach the maximum)
(1) The contact position of the feedback lever with the actuator stem connector is incorrect.
(2) permanent magnets produce magnetic field strength smaller than the rated value.
(3) the baffle and the nozzle with the poor.
(4) The initial position of the feedback cam is poorly selected.
(5) Poor main lever balance spring installation.
5. Lower stroke positioner output pressure changes slowly
(1) The taper of the gas cone valve of the amplifier is small.
(2) the amplifier diaphragm long-term use, resulting in elastic hysteresis.
(3) Pneumatic positioner sensing element (bellows or diaphragm) for long-term use, resulting in elastic hysteresis.
(4) feedback spring to produce elastic lag.
6. The stroke locator gives a slow change in pressure
(1) The amplifier intake ball valve is too deep.
(2) the amplifier has a large air consumption.
(3) the amplifier into the ball valve stained, reduced circulation area.
(4) The ratio of the diameter of the constant orifice to the nozzle diameter is less than the rated value (technical requirement).
(5) The fit between the nozzle and the baffle is not good.
(6) There is a slight friction between the armature and the bobbin.
Changshu City Universal Instrument Co., Ltd. is located in the economically developed, beautiful scenery
