Patent ID: 7695261
Filing Date: 2010-04-13
Classification: F04C

Abstract:
1. A positive displacement pump comprising: (a) a shaft to rotate about a longitudinal axis; (b) a rotor centrally secured to the shaft, the rotor having a body with a cylindrical surface extending between spaced ends; (c) a rotor disk secured at each end of the rotor and secured at a centre of the rotor disk to the shaft; (d) a housing defining an internal cavity within which are the rotor, the rotor disks and a portion of the shaft, the cavity defined by end walls of the housing and a cylindrical housing side wall extending between the end walls, the rotor and rotor disks centrally positioned with respect to the housing side wall; (e) fluid inlet and fluid discharge ports at spaced locations in the housing side wall; (f) two or more equally spaced, radially oriented slots in the rotor, longitudinally extending across the rotor and its cylindrical surface; (g) two or more similar planar vanes, each having internal and external edges extending between sides, each vane slidably seated in a different one of said slots, each vane moveable radially in its corresponding slot between an extended position with the external edge of the vane extending beyond the cylindrical surface of the rotor, adjacent the side wall of the housing, and a retracted position wherein the external edge of the vane does not extend beyond the cylindrical surface of the rotor, the vanes being spaced from adjacent vanes about the rotor such that there is always at least one vane positioned between the inlet and discharge ports, the sides of the vanes slidably seated in corresponding slots in the rotor disks; (h) pins extending outwardly from opposite sides at similar locations on the vanes, the pins passing through slots in the corresponding rotor disks and ends of the pins being seated, for sliding movement, in races formed in interior surfaces of the housing end walls; (i) a discharge chamber with which the discharge port directly communicates, the discharge chamber having opposed, spaced, upstream and downstream walls, and an exit for passage of fluid; (j) a dam moveably positioned adjacent the downstream wall of the discharge chamber, the dam having an upper and lower end, its lower end extending into the internal cavity of the housing and positioned so as to be close to or in sliding contact with the cylindrical surface of the rotor, the dam configured to extend between the rotor disks, so as to direct fluid entering the discharge chamber towards the chamber's fluid exit; the races in the interior end walls of the housing and the pins on the vanes being configured so as to cause the vanes to move to retracted position as they approach the discharge port and dam, and means being provided to cause the vanes to move to extended position when the vanes have passed the discharge port and dam.