GB1302475A - - Google Patents

Abstract

1302475 Rotary shaft seals SONESSON PUMPINDUSTRI AB 19 April 1971 [17 April 1970] 27212/71 Heading F2B A device for maintaining in a rotary pump seal chamber 7 filled with liquid or gaseous sealant a predetermined pressure relative to the centre of the impeller of the pump comprises a container 9 filled with sealant and having an inlet 16 and an outlet 10 both connected to the seal chamber and a bellows 14 within the container in communication at 17 with the pump chamber at 15, the bellows being adapted to expand axially in response to a reduction of quantity of sealant in the seal chamber (due to leakage from the seal chamber into the pump chamber) and a compression spring 18 being provided to counterbalance the spring force inherent in the bellows. The seal chamber 7 contains end-face seals 5, 6 and the sealant is circulated back to the container 9 by pumping blades 13 where it is cooled either by a cooling coil 35 having an inlet 36 and an outlet 37 or by cooling fins on the container. Sealant is replenished in the container 9 automatically through a feed device when the bellows has expanded to its maximum position 27; a permanent magnet 31 secured to the bellows by a bracket 32 operates a switch 33 to control the feed device which is shut off again when the bellows returns to the full position 30. The bellows may be made of stainless steel and the compression spring 18 may be designed to counterbalance the spring force of the bellows when the bellows is in either the maximum position 27 or the full position 30.