GB585933A - Pump - Google Patents

Abstract

585,933. Centrifugal pumps. EDWARDS' M. L. May 10, 1944, No. 8928. [Class 110 (i) A centrifugal pump for handling liquids at their boiling point, particularly for aircraft engines at high altitude, has an axial-flow impeller associated with it to return the gas in the liquid to the source of supply so that it does not interfere with the operation of the pump. In the arrangement shown, for submersion in a fuel tank, the impeller comprises a cylinder 37 supported from a sleeve 38 on the driving-shaft by a pair of helical blades 18 and provided with a flange carrying the centrifugal blades 17 ; the arrangement provides a stream of liquid, through the impeller, of which the outer gas-free portion is fed to the discharge volute 8 by the centrifugal blades. The pump is driven by an electric motor in a housing 14 which is carried by struts, containing vent passages for the motor casing and for a seal chamber 21, on a base 9 fitted into the pump casing, which is likewise carried on struts on a base 4 fixed in an opening in the bottom of the tank 1 ; the struts allow free passage of liquid to and from the impeller, the inlet passages being'surrounded by a filter screen 7. The sealing means for the motor housing comprises a carbon disc 26 on which a metal disc on the shaft rubs, and spring-pressed bellows 27. In an alternative arrangement Fig. 7 (not shown), the axis of the pump is arranged horizontally and the apparatus is fixed outside the tank, a return passage to the tank being provided on the discharge side of the axial-flow blades.