Rotary pump construction with cleaning feature

摘要

A positive fluid pump is provided which is capable of being cleaned in place by a circulating cleaning solution without the various pump components being disassembled. The impellers for the pump are rotatably mounted within a chamber formed in a housing. The inlet and the outlet for the chamber are separated from one another by the engaging impellers during normal operation of the pump. One of the side walls forming the pump chamber is provided with a cavity in which is slidably and sealingly mounted a wall piece. Under normal operation of the pump, the wall piece assumes a first position wherein one surface thereof is disposed adjacent the corresponding end faces of the impellers. When, the pump is being cleaned in place, the wall piece assumes a second position independently of the impellers wherein the one surface thereof is recessed from the pump chamber and the inlet and the outlet are interconnected permitting the cleaning solution to circulate through the chamber and around the impellers. The wall piece is retained in the first position by a predetermined pneumatic pressure exerted on a second surface of said wall piece disposed opposite said one surface. The predetermined pneumatic pressure is released when the pump is to be cleaned in place, allowing the wall piece to be moved to the second position by the circulating cleaning solution.