Pneumatic Control Valve Symbol

Directional air control valves are the building blocks of pneumatic control.

Pneumatic control valve symbol.

In the hydraulic valve fluid is returned to the tank from port t. The symbol depicts a non return or check valve which restricts the air supply so that it air is restricted in one direction and free flowing in the other direction. In the pneumatic valve return air is vented from port r. Symbols show the methods of actuation the number of positions the flow paths and the number of ports.

Most control valves however have four ports shown in hydraulic and pneumatic forms in figure 4 1. Pneumatic symbols directional control valves process valves description image description image 2 2 way valve air operated nc angle valve 2 way 2 2 way valve direct operated nc ball valve 2 way 2 2 way valve pilot operated nc ball valve 3 way l 3 2 way valve air operated nc ball valve 3 way t. Bidirectional flow control bidirectional control valve symbols are the same as unidirectional but without the check valve indicating that the air is restricted in either direction. Symbol description a position 2 wav s way 4 way 2 position 4 way way pot.

These six basic valve symbols when combined with the basic actuator symbols comprise virtually all the directional valve symbols needed for air logic control. In both the load is connected to ports labeled a b and the pressure supply from pump or compressor to port p. For example the note 2 300 rf pb indicates that the p id calls for this valve to be a 2 ansi 300 raised face piston balanced valve. The symbols for these valve functions are shown in left graphic.

Air preparation units pneumatic valves cont d valve actuators symbol descrlptlon filter separator. Pneumatic valves description flow control. 5 3 way single pilot pneumatic valve pneumatically actuated in both directions spring centred exhausted in mid position 1 2 3 4. An engineer may also include specific details below the control valve symbol.

These details may include the size function pressure rating and connection type of the valve. Pneumatic circuit symbols representing these valves provide detailed information about the valve they represent.