Centrifugal trash pump

A centrifugal trash pump comprising:

• (A) a pump casing which has a pump chamber formed therein;
• (B) a rotatable impeller which is housed in said pump chamber;
• (C) a volute which is housed in said pump chamber;
• and
• (D) a cover, said cover 1) being fastened to said volute by a volute fasteners accessible from an exterior surface of said cover and 2) being fastened to said pump casing by cover fasteners, wherein said cover fasteners and said volute fasteners can be unfastened independently of one another to selectively 1) permit said cover and said volute to be removed from said pump casing as a unit and 2) permit said cover to be removed from said pump casing while leaving said volute in said pump chamber.

A self-priming centrifugal pump comprising:

• (A) a pump casing which has a pump chamber formed therein;
• (B) a rotatable impeller which is housed in said pump chamber;
• and
• (C) a volute which is housed in said pump chamber, said volute having 1) an inner radial edge which is at least generally circular and which surrounds said impeller, 2) an outer radial surface which is at least general toroidal in shape, 3) a radial outlet in fluid communication with an outlet of said pump chamber, and 4) a recirculation inlet in fluid communication with said radial outlet, said radial outlet being formed from an outlet of a discharge duct, said discharge duct being dimensioned and configured to discharge a fluid stream from the outlet thereof in a flow pattern that is at least substantially tangential to said inner radial edge, wherein said discharge duct has an inner radial wall having an outer end portion that that extends 1) at least substantially linearly and 2) at least substantially tangentially to said inner radial edge.

A self-priming centrifugal trash pump comprising:

• (A) a pump casing which has a pump chamber formed therein, said pump chamber having an inlet and an outlet;
• (B) a rotatable impeller which is housed in said pump chamber;
• and
• (C) a volute which is removably installed in said pump chamber so as to surround said impeller, said volute having 1) an inner radial edge that is at least generally circular, 2) an outer radial surface that is at least general toroidal, 3) an axial inlet in fluid communication with said inlet of said pump chamber, 4) a radial outlet in fluid communication with said outlet of said pump chamber, and 5) a recirculation inlet in fluid communication with said radial outlet, said radial outlet being formed from an outlet of a discharge duct of said volute, said discharge duct being dimensioned and configured to discharge fluid from an outlet thereof in a flow pattern that is at least substantially tangential to said inner radial edge, wherein said discharge duct has inner and outer radial walls, each of which has an outer end portion which extends 1) at least substantially linearly and 2) at least substantially tangentially to said inner radial edge.