Transforming mechanical movement into pneumatic signal - using pneumatic constant resistance device to control relay

摘要

Air passes from the pipe (2) through the passages (9) and (10) through the pipe (16) and out through the nozzle (8). The quantity of air flowing through the nozzle (8) depends on the size of the gap between the nozzle end face and the plate (7). If the flow is reduced the velocity of the air through the holes (9) and (10) is reduced, reducing the suction effect in the chamber (13) causing an increase in pressure. Thus the pressure of the air supplied to the relay (1) depends on the size of the gap between the nozzle (8) and plate (7). The design of the relay is such that the output pressure in the pipe (3) varies linearly with this gap.