Air bearings manufactured by Professional Instruments use the exclusive Groove Compensation Principle (U.S. Patent 3,305,282). Air at full line pressure is introduced between two bearing surfaces, one of which has a number of calibrated grooves which control the pressure gradients within the bearing film in such a way that restoring forces are generated in proportion to displacement of the bearing members from their nominal clearance.

This system offers several improvements over orifice and porous bearings:

1. The inherent stability of the air bearing film is high because squeeze film effects are maximized by the use of thin air films, long flow paths and the absence of upstream restriction.
2. Viscous damping of externally excited vibration is enhanced by the relatively high average pressure of the bearing film with the consequent reduction of its compressibility.
3. The grooves direct the air along the bearing so that undesired circumferential flow is minimized.