GB719248A - Self-priming centrifugal pumps - Google Patents

Abstract

719,248. Centrifugal pumps. PULSOMETER ENGINEERING CO., Ltd., and PRICE, A. V. April 7, 1953 [April 15, 1952], No. 9369/52. Class 110(1) A self-priming centrifugal pump comprises an auxiliary impeller with an inlet which is separate from that of the main impeller and is arranged to be submerged in liquid, and communicating passages leading from the main impeller to the auxiliary impeller, the flow of liquid through the auxiliary impeller exerting an ejector effect to draw off air or other gases from the main impeller. The auxiliary impeller comprises vanes 26 formed on the rear wall 23 of the main impeller 22. Initially, the whole of the pump is filled with water. On rotation, the auxiliary impeller draws water from a reservoir 12 through a passage 16 and delivers it to a discharge volute 13. In passing the communicating passages 27, the liquid flowing through the auxiliary impeller exerts an ejector effect and draws water from the main impeller, together with any entrained air or gas, thereby priming the pump. The air or gas separates from the water in the volute 13 and passes to the delivery pipe, while the water passes from the top of the volute to the reservoir 12. When the pump is stopped, water will remain in the reservoir 12 at least up to the lowest discharge level of the volute 13, so that on subsequent operation of the pump the auxiliary impeller will automatically exert its priming function. The auxiliary impeller may be shrouded and may be arranged on the front wall instead of the back wall of the main impeller. Or, there may be auxiliary impellers on both walls.