Paper 2: Glandless Pump–Motor Units for Feed Heating Plant in Central Power Stations

Abstract

This paper outlines the need for glandless pump–motor units in modern feed heating plant. It describes the design, construction, and testing of a prototype glandless centrifugal pump with integral squirrel cage motor. The composite unit is for deaerator lift duty in the feed heating system of a 500-MW generating set. The principal hydraulic features, mechanical construction, motor cooling and bearing lubrication system, and stator and rotor construction are outlined. An account is given of the glands used to bring the electrical connections through the pressure casing wall and of the special terminal arrangement. Works and site testing are described and the results discussed. Preparations for transport and precautions required during storage and installation at site to minimize corrosion are considered. Machines developed from the prototype are described, with particular reference to the use of coaxial stator conductors, combined pressure casing/stator frame construction, improved water lubrication system, resiliently mounted thrust bearing, suction stage axial inducer, and axial entry diffuser.