Page 45 - PNEUMATIC SYSTEM INSTRUMENT

CHARACTERISTIC OF DIRECTIONAL CONTROL VALVE

The directional control valve controls the passage of air signals by

generating, cancelling, or redirecting signals. In the field of control

technology, the size and construction of the valve is of less importance

than the signal generation and the actuation method. Directional

control valves can be of the poppet or slide type, with the poppet

utilized for small flow rates and for the generation of input and

process signals. The slide valve can carry larger flow rates and hence

lends itself to the power and actuator control role.

The way valve is described by:

 Number of ports or openings (ways): 2-way, 3-way, 4-way, 5-

way, etc.

 Number of positions: 2 positions, 3 positions, etc.

 Methods of actuation of the valve: Manual, air pilot, solenoid,

etc.

 Methods of return actuation: Spring return, air return, etc.

 Special features of operation: Manual overrides, etc.

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