ROTARY PUMP

1454270 Centrifugal pumps ITT INDUSTRIES Inc 8 April 1975 [9 April 1974] 14320/75 Heading F1C In a motor-driven centrifugal pump of the kind in which the impeller 3 is disposed to one side of the pumping chamber 4 so that the pumping effect is obtained by the generation of a swirl in the chamber in front of the impeller, at least part of the pump casing 8 is resilient so that when a predetermined volumetric flow is reached, deformation of the part occurs to tend to prevent further increase of the flow. The casing 8 comprises a rigid outer part 7 of sheet metal and an inner part 9 of resilient material, such as rubber. When a predetermined volumetric flow is reached, the front portion of the casing inner part 9 deforms around the inlet opening and becomes folded inwardly against the impeller hub 6 to throttle the flow and prevent further increase.