Scanning For Ideas: Shaped Pistons Let Air Cylinder Move Smoothly
March 6, 2008
Most air cylinders are prone to wear and contamination, don’t withstand extreme temperatures, and generate significant friction.
Edited by Stephen J. Mraz
The Airpel-AB single-acting (air-extend) pneumatic drivers from Airpot Corp., Norwalk, Conn. (airpot.com), overcome these limitations with a specially shaped steel piston fitted to a borosilicate glass cylinder. Putting pressurized air into the cylinder creates an air-bearing airflow effect around the piston. So the same air that drives the cylinder generates a stiff cushion of air that supports the piston around its edge, preventing contact with the cylinder wall and reducing friction without lubricants. A low-friction ball joint connects the rod to actuator, so no output force is lost to friction.
The AB line is offered in four bore diameters and 10 strokes, and can provide driving or supporting forces ranging from 2 gm to 58 kg at pressures starting at 5 psi. They operate in temperatures from –20 to 90°C. Because there is little friction or wear, the manufacturer guarantees their AB air cylinder will outlast any piece of equipment in which it is installed.
