Pneumatic logic not gate - is controlled by progressively varying pressure and has two destintive switching thresholds

摘要

Pneumatic logic device having a NOT function for use in a respirator has a body with an admission chamber (2) and inlet, (E), outlet (5) and drain (P) orifices connected to the chamber. A control chamber having a control orifice (C) has a deformable element (11) with an integral push member (9). A movable valve in the admission chamber is capable of bearing alternately against inlet (5) and drain seats (6) situated opposite each other. The seats feed the inlet and drain orifices respectively. The push member is capable of acting on the valve through the drain seat to move the valve towards the inlet seat to connect the drain and outlet orifices. The inlet seat forms a passage of smaller cross-section than the drain seat.