Self-draining centrifugal pump having an improved inlet

An improved centrifugal pump for use in whirlpool bath systems, the pump having an axis and an electric motor with a shaft along the axis and the shaft turning an impeller in a volute, an offset inlet positioned below the axis for delivering water to the impeller and volute through an entrance along the axis and an outlet for transferring pressurized water to a whirlpool bath system;

• the improvement comprising:
• an inlet chamber configured between said offset inlet and said entrance, said chamber forming a smooth transition from inlet to impeller and having a shape permitting one-step injection molding using two opposed cores that are removed from the molded inlet chamber in opposite directions;
• wherein said chamber comprises an interior wall having upper and lower sections, the cross-sections of which are in the shape of circular segments and having side sections which are substantially flat.

An improved centrifugal pump for use in whirlpool bath systems, the pump having an axis and an electric motor with a shaft along the axis and the shaft turning an impeller in a volute, an offset inlet positioned below the axis for delivering water to the impeller and volute through an entrance along the axis and an outlet for transferring pressurized water to a whirlpool bath system;

• the improvement comprising:
• an inlet chamber configured between said offset inlet and said entrance, said chamber forming a smooth transition from inlet to impeller and having a shape permitting one-step injection molding using two opposed cores that are removed from the molded inlet chamber in opposite directions;
• wherein said inlet and said entrance each have substantially circular cross-sections of unequal diameters, and wherein said chamber has cross-sections along substantially its entire length which are non-circular.

An improved centrifugal pump for use in whirlpool bath systems, the pump having an axis and an electric motor with a shaft along the axis and the shaft turning an impeller in a volute, an offset inlet positioned below the axis for delivering water to the impeller and volute through an entrance along the axis and an outlet for transferring pressurized water to a whirlpool bath system;

• the improvement comprising:
• an inlet chamber configured between said offset inlet and said entrance, said chamber forming a smooth transition from inlet to impeller and having a shape permitting one-step injection molding using two opposed cores that are removed from the molded inlet chamber in opposite directions;
• further comprising an air induction tube connected to said chamber for effectively stopping pumping action without deactivating said motor.