A Study of Ceramic Bearing for Vertical Pumps : Friction Coefficients of Submersible Bearings in Air and Water

Abstract

Friction coefficients in air and water of various sleeve-type submersible bearings for vertical pumps were investigated with respect to a variety of bearing materials including SiC-sintered ceramics, WC-cemented carbides, self-fluxing alloys and conventional bearing materials such as rubber, resins, PTFE # and soft sintered alloys. The test equipment simulated the frictional conditions of actual vertical pump shafts, that is, the shaft of the testing apparatus precessed against the bearing. The results showed that when silicon carbide was used as a stationary bearing, lower friction coefficients could be obtained, regardless of the material used for the rotating sleeve. In slurries, the abrasive particles adversely affected the friction coefficients of conventional bearings, however, owing to superior hardness, ceramic bearings maintained low friction coefficients. In air, a combination of silicon carbide and tungsten carbide displayed a low friction coefficient. Also, the results confirmed that dry starting of vertical pumps is also possible when using this combination of materials.