GB202780A - Improvements in centrifugal pumps - Google Patents

Abstract

202,780. Little, J. June 14, 1922. Casings; regulating.- A centrifugal pump has means for controlling automatically the effective delivery area of the impeller so that the quantity of fluid is approximately constant when the head against which the pump is working is decreased. The casing is in two parts 1, 2 which carry the inlet 3 and delivery 4 respectively. An inner rotatable casing has portions 5, 6 the former 5 of which carries impeller blades 7 which are also attached to a plate 8 secured to the end of the driving shaft 9. A diffusion chamber is formed by plates 13, 14; the plate 14 is carried by arms 24 on the bearing sleeve 16 and the plate 13 with its peripheral flange 27 is carried by the rod 15 which can slide in the sleeve 16 but cannot rotate. The outer end of the rod has a piston 17 working in a cylinder 18 under the control of a spring 22 which can be adjusted by the screw 20 and the slide 21. The cylinder 18 is in communication with the pump delivery through the channel 23. When the pump is working the piston 17 occupies a position in which the delivery pressure is balanced against the spring pressure; as the head decreases the spring moves the piston and this operates the diffusion plate 13 and its flange 27 over the effective delivery area of the impeller thus keeping the quantity approximately constant. Apertures 25 are provided in the parts 5, 6 to equalize the pressure in the impeller chamber and in the surrounding casting. Similar apertures are provided in the plate 13.