DEVICE FOR MONITORING ABRASION LOSS OF A THRUST BEARING IN A SUBMERGED MOTOR PUMP

摘要

A submerged motor pump is provided in a piping system or connected to a pressure vessel, and a pump and a motor are immersed in the fluid. A rotor rotatable together with a pump impeller is fixed to a rotor shaft. The rotor shaft is supported by a thrust bearing. A cover is provided facing the end of the rotor shaft and carries an ultrasonic sensor on its outside surface. The ultrasonic sensor projects ultrasonic wave toward the end of the rotor shaft and detects the echo therefrom so as to measure the distance between the end of the rotor shaft and the inside surface of the cover, i.e. the surface thereof in contact with the fluid. The inside surface of the cover includes a concave spherical surface which faces the end of the rotor shaft and substantially converges the main beam of the ultrasonic wave to the end of the rotor shaft, preventing reduction of sound pressure of the ultrasonic wave.