A device (generally a pneumatic cylinder and piston) which induces action or motion with compressed air being the medium through which the power is transmitted. They are categorised mainly by Single acting and Double acting types.
Single acting:
Double acting:
A single-acting cylinder (SAC) has one port, which allows compressed air to enter and for the rod to move in one direction only. The high pressure of the compressed air causes the rod to extend as the cylinder chamber continues to fill. When the compressed air leaves the cylinder through the same port the rod is returned to its original position.
Double-acting cylinders (DAC) use the force of air to move in both extend and retract strokes. They have two ports to allow air in, one for outstroke and one for instroke. Stroke length for this design is not limited, however, the piston rod is more vulnerable to buckling and bending. Additional calculations should be performed as well.
After carrying out the work or a stroke, the air inside the cylinder is exhausted to the atmosphere, causing loss of compressed air. Higher the air pressure, higher is the loss of compressed air. An air cylinder that is specified to use 30 psig, will use 70% more air at 60 psig, 230% more air at 90 psig and 300% more air at 120 psig.