Development Of A Magnetic Bearing, API Process Pump With A Canned Motor

Abstract

A new class of pumps has been developed where both end face seals and contacting bearings are eliminated. The objective is to provide a sealless pump with long life bearings meeting the duty requirements of API Standard 620 for centrifugal pumps. The pump combines hydraulic components, impellers and volute, vases, from existing product lines, with a derivative canned motor and an active magnetic bearing system capable of supporting the pump loads under all operating conditions. A prototype pump has been built and tested. The tests were successful in proving the concept and after correction of minor manufacturing problems, the pump is expected to enter field demonstration service in early 1992. Besides providing a pump with no mechanically contacting surfaces, the addition of magnetic bearings provides useful diagnostic output of pump loads and rotordynamics generally not available in prior designs. These new capabilities should prove very useful in the evaluation and planned maintenance of magnetic bearing equipped pumps.