Double helical flowmeter

Flowmeter apparatus, comprising a case having a cavity, intermeshing double helical rotors mounted for rotation within the cavity and a cover closing the cavity and holding the rotors within the cavity, the cavity having an inlet at one side and an outlet at an opposite side for flowing fluid into the cavity through the inlet and around the meshing double helical rotors and out of the cavity through the outlet, and a sensing device mounted on the case or cover for sensing rotation of the double helical rotors, wherein each of the rotors has two or more double helical lobes and large volume transfer pockets alternately in communication with the inlet port, in isolation from the inlet and outlet ports, and in communication with the outlet port, and wherein the high volume transfer pockets have curved surfaces which slope inward from axial outer surfaces of the rotors toward an axial center of the rotors.

Flow meter apparatus comprising a housing, two intermeshing double helical rotors rotatable in the housing, the double helical rotors having plural lobes extending generally helically and axially from central sections between axial ends of the double helical rotors, the lobes engaging with lobes from intermeshing double helical rotors near a center of the housing, and the lobes extending to internal walls of the housing, the double helical rotors having pockets between the lobes for transporting fluid in measurable quantities through the flowmeter and a means for sensing rotation of the double helical.