Magnetic clutch drive and thrust balancing mechanism for rotary pumps

Abstract

A magnetic clutch drive for rotary pumps is characterized by a motor driven outer magnetic clutch member juxtaposed to an imperforate wall of a pump housing. Within the interior of the housing a pump impeller shaft carries an inner magnetic clutch member juxtaposed to the wall opposite from the outer member. The wall is of a nonmagnetic and electrically nonconductive material, so magnetic lines of force penetrate the wall and magnetically lock the outer and inner clutch members, without any mechanical connection between the two. Consequently, as the motor is brought up to speed, the two clutch members magnetically lock the motor shaft to the impeller shaft to drive the impeller shaft at the same speed as the motor shaft, without generating eddy current losses in the wall. Also included is a thrust balancing mechanism that uses the pressure of pumped liquid to develop and exert on the impeller shaft a force substantially equal in magnitude and opposite in direction to thrust forces exerted on the shaft during pump operation, and the interior of the housing wall is pressurized to maintain a dry operating environment for the inner clutch member.