GB1321388A - Fluid pumps - Google Patents

Abstract

1321388 Rotary shaft seals APPLETON & HOWARD Ltd 25 April 1972 [8 June 1971] 19375/71 Heading F2B In a rotary pump, particularly for use with corrosive liquids, in which the drive shaft 4 is sealed, when the pump is in operation, by an auxiliary impeller or impellers each rotatable in a chamber 2 communicating with the main pump chamber 1, the or each impeller is carried by a sleeve on and rotatable with the shaft, one end of the sleeve being radially contractable to facilitate the or each impeller being assembled on or removed from the sleeve when the latter is removed from the shaft. The sleeve 8 extends through a seal housing cover 3 and is secured to the shaft by a clamp ring 9. The impellers 11 together with a diaphragm 10 and a spacer 12 are mounted on a reduced diameter portion of the sleeve, flats in the apertures of the bosses 11a and 6a of the impellers and diaphragm engaging a flat (not shown) on the sleeve. The diaphragm is located adjacent a stationary sealing element 6 clamped between the cover 3 and the seal housing and plates 13 located by a snap ring 15 form separate chambers for each impeller. The sleeve, impellers and diaphragm are of plastics material and the end of the sleeve remote from clamp ring 9 is formed with axially extending slots (not shown) to render it radially contractable when the sleeve is not on the shaft. When the pump is at rest, leakage is prevented by the diaphragm 10 contacting the element 6. During pump operation, the diaphragm is withdrawn from element 6 by the reduction in pressure on the pump side of it caused by the impellers 11. A drainage conduit 16 is provided in the cover 3.