Pneumatic Valves

Coaxial pneumatic valves.

The picture on the right shows an externally compressed air pilot controlled 2/2 way normally closed coax valve, in this case the solenoid coil is replaced with a pneumatic piston (3) and the connector replaced by 2 air control inlet pilot holes (6) which are typically surrounded by four namur mounting holes so that 5/2 way namur interface solenoid controllers can be directly mounted to the valve body to control the compressed air supply. With inlet port P (1) and outlet port A a normally closed valve at rest will prevent flow from P to A as the tube (3) is resting against the sealing face (2). When compressed air is allowed into this air coax valve pilot hole (6) the piston moves laterally (coaxial movement) from right to left away from the sealing face (2) allowing flow. when compressed air is removed the internal spring will push the tube back to its rest position to seal (2) thus preventing flow through the valve. These valve can be supplied 2/2 way normally open so that the spring keeps the valve in open position with compressed air to close.  

Coaxial air operated valves are also available in 3/2 way format, 3 ports 2 positions. This is basically a third port (R) or exhaust port at 90 degrees to port P (basically when diagram item 1 points) and is either open when port A is closed (tube to the right exposing R), or closed when port A is open tube to the left covering R.