How to Read Pneumatic Schematic Symbols....

The block  

• The block symbolizes the possible valve functions or positions. Example: A 5/2 valve schematic will be illustrated with 2 blocks describing two valve functions or positions. A 5/3 valve schematic will show three blocks describing 3 possible valve functions or positions.

        The Actuator

• Pneumatic valves can be operated in several ways. Hand operated ( including levers and push and or push pull buttons) ; Air piloted (Operated remotely by pneumatic signals); Solenoid (directly actuated with electronic signals)
• A is pressurized and B is exhausted
• B is pressurized and A is exhausted.

       The arrows

• The Arrow symbols illustrate the direction of gasses flowing into and out of the valve ports. Gas is pressure is supplied from port P. Depending on which of the valve blocks is in function, the gas is directed to port A or B as shown by the arrows.

        Exhaust Port 

• The inverted triangle symbol denotes an exhaust port. The letters EA indicate this is the exhaust port for the A circuit. Ebin turn indicates the exhaust port for the B circuit.  

       The Return spring

• The spring symbol defines the "at rest" position of the solenoid valve. The spring "Pushes" from the side it is drawn on and places the right side block diagram of the valve in function.

        The T Symbol

• This symbol indicates that a port is closed and is neither passing or exhausting gas.

        Pressure or Air supply symbol

• This symbol indicates the air supply port. In addition to this symbol the letter P or the number 1 also indicates the air supply port.

Example valve