GB190726368A - Improvements in or relating to Centrifugal Pumps. - Google Patents

Abstract

26,368. Rossiter, J. T. Nov. 28. Centrifugal pumps.- The crosssectional area of centrifugal-pump impeller-passages is diminished gradually from the suction-eye to the periphery so as to increase the velocity of the fluid gradually, and the surrounding casing passages are divergent. The impellers may be formed in two sections which may be separated axially to vary the discharge. The impeller shown in Fig. 1 comprises a hub e carrying four blades f to which side disks g are attached by screws. The disks are further connected by intermediate blades which do not extend to the hub. The disks are formed separately to facilitate turning to the required shape, and polishing to reduce friction. The casing consists of two sections a, a<1>, machined to form a bladeless diverging nozzle b and a good running joint at b<1>. The flow of liquid through the rotary and stationary passages resembles the steady flow in a Venturi tube. The velocity at the periphery of the impeller is high, and the injector action reduces the pressure in the region a<8>, thus minimizing leakage. This effect is intensified by fixing small blades g<1> on the outside of the disks. The impeller shown in Fig. 4 is divided into two sections in a plane at right-angles to its axis. The duty of the pump may be varied by separating the side disks g by threading washers on the shaft and on the screws holding the disks and blades together. The arrangement of these holding - screws may be modified in detail. In the modification shown in Fig. 7, the disks g are rendered axially adjustable by being screwed to rings c<*> carried by the hub e. In another modification, the impeller is cast in one piece and a slot is turned in the peripheral portion. Adjustment is obtained by means of screws which spring the disks g together at the periphery. According to the Provisional Specification, one disk g may be fixed and the other movable. The impeller shown in Fig. 4 is fitted with blades of the form shown in Fig. 5 so that the pump may be run in either direction. Such pumps may be arranged in parallel or in series. Fig. 12 shows a multi-stage arrangement in which the first impeller is divided along the line n<1>, succeeding impellers being divided along the line n.