What is quick exhaust valve? Application of quick exhaust valve

Quick exhaust valve

Quick exhaust valve is a device that enhances the speed of pneumatic cylinder in extend or retract cycle.Usually it is used for pneumatic applications where quick air pressure exhaust are needed. Quick exhaust valve 
It is installed to the cylinder rod end or blind end and connected to threaded ports. If exerted pressure is removed from QEV valve which create a back-flow to output port and seat the valve component in resulting exhaust the air pressure to the atmosphere. 

The symbols of the valve indicates the connection diagram of the valve. There are three connection port of the valve A,P & R. 

A is the outlet port
P is pressure port
R is exhaust port

When pressurized air connected to pressure port P and internal valve unseated and allows air flow to go Outlet port A. When pressure removed from P port, the check valve piston allows the flow of air from A port to exhaust port R. This is how the quick exhaust valve work. 

How to works Quick exhaust valve with cylinder

We are going to discuss about the illustration of quick exhaust valve. Usually it is installed in the inlet of single acting or double acting cylinder.Pressurized air is directly connected to the exhaust valve input and makes a free flow to the outlet port and enters into the cylinder. Pressurized air flow forces to the piston and extends rod slowly than retract cycle. 
When the cylinder retract poppet seated and airflow exhaust to the atmosphere very fast than extend cycle of cylinder. 

 

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