Pump apparatus

Claim 1

A pump apparatus comprising: a regenerative pump including a pump housing formed therein with suction and discharge ports and a disc-like impeller mounted in said housing for rotation therein and for axial movement within a limited range; driving means drivingly connected to said impeller to rotate the same for thereby pumping a fluid; said impeller having substantially constant thickness and having substantially circular and substantially planar end faces and being provided with circumferential rows of radial vane grooves formed in said end faces adjacent to the outer periphery of said impeller; said pump housing cooperating with said impeller to define a circumferential passage surrounding said circumferential rows of radial vane grooves and communicated with said suction and discharge ports; said pump housing having substantially circular and substantially planar inner surfaces opposed to said end faces of said impeller, respectively, to cooperate therewith to form a first set of sealing sections extending over substantially the entire surface areas of said impeller end faces, respectively; and means for axially centering said impeller within said pump housing to keep at least the major surface areas of the opposite end faces of said impeller closely spaced axially from said substantially circular inner surfaces of said pump housing, the axial spacings between said impeller and said pump housing being substantially uniform within said first set of sealing sections; said centering means including spacer means comprising circumferentially continuous annular projections formed on at least one of said impeller and said pump housing in parts of said first set of sealing sections to cooperate with the other of said impeller and said pump housing to form a second set of sealing sections.