The dominant manufacturer of dry air pumps is Airborne, a division of Parker-Hannifin Corporation located in Elyria, Ohio. Airborne manufactures a wide range of air pumps, regulators, filters, check valves, air manifolds, and also control valves for pneumatic deicing systems. All Airborne pumps are built with a slotted graphite hub and graphite vanes. The hub and vanes rotate within a polished elliptical interior cavity within the aluminum pump housing. The vanes are free to slide in and out of the hub slots as they rotate within the eccentric cavity.
Centrifugal force holds the vanes against the cavity wall, providing the requisite air-tight seal.
The pump drive incorporates a frangible plastic coupling that is designed to shear instantly if the pump's rotational drag exceeds normal operating torque by any significant amount. This ensures that a pump failure cannot damage the engine's accessory drive. The hub slots of Airborne pumps are canted in the direction of rotation. For this reason, Airborne offers different pump models for clockwise and counterclockwise applications. It's not difficult to break the code.