GB689445A - Improvements in and relating to composite pumps - Google Patents

Abstract

689,445. Centrifugal pumps. BRITISH THOMSON-HOUSTON CO., Ltd. Aug. 30, 1951 [Sept. 12, 1950], No. 20507/51. Class 110(i) A pump supplies liquid under pressure to a centrifugal pump, the inlet of which is also connected to a reservoir open to the atmosphere, so that when the rate of discharge of the centrifugal pump is less than the rate of supply of liquid to it from the other pump, the excess liquid fills the reservoir and overflows so as to maintain a constant static head at the centrifugal pump inlet. A gear pump 6, 7, Fig. 2, supplies oil for lubricating the bearings of a turbine and for use as the hydraulic power medium in the turbine governing system described in Specification 663,935, whilst a centrifugal impeller 9 of the circumferential-flow type provides the "pressure-signal", i.e., a hydraulic pressure which is proportional to the turbine speed. Leakage of oil from the gear pump, as through bearing lubricating grooves 6d, 7d, to to a recess 20 in a plate 3 provides the small amount of oil pumped by the impeller 9 and in addition affords a surplus which rises through a duct 16b, 16, 16c to a reservoir 12 and overflows over a wall 13. Thus, the reservoir 12 is kept full to provide a constant static head at the inlet of the centrifugal pump and to prime the centrifugal pump. A groove 23, Fig. 4, leads from the recess 20 to an annular pumping groove 24, where the oil is acted on by the impeller blades 9c and discharged through a duct 17a. The impeller 9 is loosely keyed to the shaft 7c so as to be able to centre itself between lands 22 and 27 on plates 3 and 4. Plate 2 is located relative to the pump housing 1 by dowel pins 19 and may be formed with an annular land 2a which registers with the recess 20 to locate the plate 3. Similarly, plate 4 may be located by a land 4a. The impeller 9 may be of the constructions described in Specifications 663,935 and 673,796. The gear pump may be replaced by other types of positive displacement pump. Specification 673,780 also is referred to.