Ioric pump with cast impeller housing requiring three machined surfaces

Abstract

A toric pump has a metal impeller housing formed with a flat end face into which an annular impeller receiving recess extends to a depth which exceeds the axial thickness of the impeller mounted in the recess by an amount only sufficient to provide a minimum operating clearance for the impeller sides when an impeller cover is mounted on the housing with a flat end face of the impeller cover in sealed face to face engagement with the flat end face of the housing. A bore in the impeller housing receives a cylindrical portion of the pump drive motor to accurately locate the rotary axis of the impeller with respect to the peripheral side surface of the stripper portion of the pump housing. All impeller-stripper portion clearances are established by machining of the die cast impeller housing and the formation of a flat surface on the impeller cover. A filter cover mounted upon the impeller cover cooperatively defines with the impeller cover an enclosed filter receiving chamber having an externally accessible inlet port opening into the chamber through the filter cover and a pump inlet passage opening from the filter chamber into a pump chamber recessed into the flat end face of the impeller cover. The impeller cover is formed with an externally accessible outlet port communicating with the pump chamber. A resilient block of filter media is enclosed in the filter chamber to filter air or other fluid flowing through the chamber from the inlet port to the pump inlet passage.