Pneumatic circuit

A pneumatic circuit is an interconnected set of components that convert compressed gas (usually air) into mechanical work. In the normal sense of the term, the circuit must include a compressor or compressor-fed tank.

Components

The circuit comprises the following components:

• Active components
  • Compressor
• Transmission lines
  • Air tank
  • Pneumatic hoses
  • Open atmosphere (for returning the spent gas to the compressor)
  • Valves
• Passive components
  • Pneumatic cylinders
  • Service Unit
• FRL - Filter Regulator and Lubricator

Pneumatic Cylinder

In general, based on the application, a pneumatic cylinder is usually a single acting cylinder, where there is a single port in the cylinder and were cylinder extension is done by compressed air and retraction by means of open coiled spring. In double acting cylinders two ports both extend and retract by means of compressed air.

Direction control valve (DCV)

The direction control valve is used to control the direction of flow of compressed air. Usually classified into normally open (NO)and normally closed (NC)valves. The normally open valves will permit flow from inlet port of valve to outlet port normally the flow will be cut by changing the position of the valve. The normally closed valves will not permit flow from inlet port of valve to outlet port normally the flow will be permitted only by changing the position of the valve. In general valves are designated as 2/2 DCV, 3/2DCV, 5/2 DCV,5/3 DCV etc. In which the first numerical indicates number of ports and second numerical indicates number of position To change the position, the valves are generally actuated by:

• Pedal Operated
• Push button operated
• Spring operated
• Solenoid operated
• By using Pneumatic source itself etc.

The other auxiliary valves are:

• Two pressure valve (And Valve): Usually two valve actuators (push buttons) are used when both the push buttons are pressed at a time the air flow takes place if either any one is pressed at a time air flow will not take place in valve outlet. Generally used in mechanical press and machine tools to ensure operator's hands are safe during operation.
• OR Valve : Usually two valve actuators (push buttons) are used when either one push button is pressed the air flow takes place.
• Check valve: Allows air flow in one direction
• Quick exhaust valve: The valve construction is OR valve with exhaust port,ensures quick return of cylinder therefore cycle time reduces
• Flow control valve:
• Time delay valve:
• Pressure relief valve etc.

The following devices operate using compressed gases, but are not normally thought of as being pneumatic circuits:

• Guns
• Rockets
• Refrigerators
• Internal combustion engines
• Scuba sets

See also

• Compressed air
• Pneumatics
• Circuit (disambiguation)
• Fluidics
• Circuit dynamics

External links