Patent ID: 6896502

Claim:
A positive displacement pump comprising: (a) a casing having an interior chamber and an inlet and an outlet oppositely spaced within the chamber and communicating therewith; the chamber having a side wall of predetermined shape extending between end walls; (b) a rotor with a cylindrical outer surface, the rotor secured in offset position within the chamber so that the rotor cylindrical outer surface is adjacent the chamber side wall at a point centrally positioned between the inlet and outlet, so as to rotate about an axis extending between the end walls; (c) an end disk secured to each end of the rotor the end disks extending beyond the cylindrical outer surface of the rotor and the chamber side wall; and (d) three planar vanes, having sides and inner and outer edges, each vane slidably movable outwardly and inwardly within slots in the rotor and end disks, between extended position and retracted position, sides of the vanes seated within the end disk slots and outer edges of the vanes being in constant contact with the side wall of the chamber, inner edges of the vanes constantly movably seated in the rotor slots during operation of the pump, and outward movement of the vanes being caused by centrifugal force, inward movement of the vanes being caused by a cam action of the side wall of the chamber bearing on outer edges of the vanes, the slots in the rotor within which the vanes are seated are formed along a chord when the rotor is viewed in lateral cross section, through sections of the vanes and are orientated so that their planes lie at 60° angles to the planes of adjacent slots.