Metallized Carbon Corporation, a manufacture of oil-free, self-lubricating, carbon-graphite materials for severe service lubrication applications, is promoting its Metcar carbon- graphite bushings for use in gear pumps that pump aviation fuel for aircraft engines. The carbon-graphite bushings are used to support both the drive gear shaft and the idler gear shaft.

Metcar carbon-graphite bushings can use aviation fuel as the bushing lubricant. Aviation fuel is a low viscosity liquid that produces only an extremely thin hydrodynamic film, too thin to provide adequate lubrication for traditional metallic bushings. But since Metcar’s carbon-graphite material has no atomic attraction to a metallic shaft, the thin fuel film is sufficient to lubricate metallic shafts running in the carbon-graphite bushings.

These carbon-graphite bushings is that they are self-lubricating and can run dry for short periods of time without catastrophic pump failure or significant wear. In addition, Metcar carbon-graphite bushings are dimensionally stable, which permits the close bushing to shaft running clearances that are required in gear pump applications.

Finally, the bushings have a relatively low elastic modulus so they can be press-fit into the metallic gear pump housing.