Reentry centrifugal pump/mixers

Claim 1

In a reentry centrifugal pump having a housing defining a generally toroidal fluid working chamber therein and a shaft concentric with said chamber and extending outward from said housing: a rotor within said housing having at least one cavity formed therein, said cavity forming a portion of said toroidal working chamber; a plurality of circumferentially spaced blades extending from said rotor into said fluid working chamber; a stationary abutment dam at one location in said working chamber, blocking at least half the area of said chamber including essentially all the area not swept by said blades; a dual thread helical face on said abutment facing the approaching blade direction wherein said helical surfaces are phased one from the other such that when the first of said helical surfaces is in alignment with a blade surface in the radial outer portion of the working chamber, the second helical surface will be in alignment with the same blade surface in the inner portion of the working chamber and where the pitch of said helical surfaces approximates the helix angle of the fluid whirl near the discharge from the pump at the pump''s design flow rate; a divergent discharge passage extending from said working chamber to the exterior of aforesaid housing, said passage being essentially tangential to said chamber at its outer portion and in line with and an extension of said first helical surface on said abutment; a circumferential surface on said abutment in close running sealing engagement with the exposed portion of said rotor blades, said surface being essentially one blade spacing in circumferential length; a partial circular bent cone or horn portion essentially centered within the working chamber extending in the direction of rotation from said abutment, a relatively high angle helical face surface surrounding said horn and beginning at the end of the outer portion of said abutment circumferential sealing surface; inlet passage means from the exterior of said housing opening into the radial inner portion of said working chamber, commencing at the end of the inner portion of said abutment circumferential sealing surface and extending approximately three blade spacings away from said abutment in the direction of rotation.