The PT pneumatic timer is a vertical surface mount timing device used mainly within the oil industry, its a reliable, robust and proven product capable of operating at temperatures of -30°C to +70°C.
Spring and diaphragm technology is used to achieve timing; the principle of operation is atmospheric pressure is used to control the timing cycle; therefore, pressure fluctuations to the timing control port will not affect timing.
A multi-purpose valve offers three connection possibilities; these are an ON delay timing, OFF delay timing and a diverter valve function. Timing options vary from 0.1 to 1 second up to 6 to 60 minutes; there are two timing sequence possibilities.
Type PT31 - Pilot pressure is continuously applied to the control port to start timing, on reaching the preselected time the directional valve switches over. Removal of the pilot pressure to the control port resets the timer and the directional valve to its spring condition.
Type PT41 - Pilot pressure of at least 100ms in duration shifts the directional valve away from its spring condition, on the removal of the pilot pressure, the timing sequence begins. The directional valve returns to its spring condition on time-out.
PT41 pneumatic timers are unique; they are the only timer where timing commences upon complete removal of compressed air to the control port, they are often used to delay the exhaust of a system upon air failure.
Setting the preset time is achieved by adjusting a large rotary knob located on the front of the pneumatic timer. Connections are via 1/8 NPT threaded ported situated to the rear of the timer.