Aquarium filter tank pump with bypass

Claim 1

A pump for an aquarium filter tank, said filter tank containing water and having filter material in said filter tank, means supporting said filter material, and a suction outlet drawing water from below said filter material, said pump comprising, in combination, a housing having a large upper portion containing a cylindrical cavity disposed at least partly above the top of said filter tank, a tangential outlet from said cylindrical cavity extending out over the top of said filter tank, a small lower portion with an inlet at the bottom thereof connected to said suction outlet, and a transition between said upper and lower portions, a motor mounted above said casing and having a shaft extending into said casing, an impeller in said housing mounted on said shaft, said impeller having a larger upper portion within said cylindrical cavity of said upper portion of said housing and a smaller lower portion extending downward within the lower portion of said housing below the level of water in said filter tank, said smaller lower portion of said impeller priming said upper portion of said housing by raising water into said cavity where efficient pumping action takes place, flow constricting control means associated with said outlet tube, said casing containing a bypass opening, and a bypass tube extending from said bypass opening into said filter tank above said filter material so that restriction of flow through said outlet tube by said control means causes flow from said bypass tube back into said filter tank.