Patent ID: 7229262
Filing Date: 2007-06-12
Classification: F01C,F04C

Abstract:
1. A rotary piston pump comprising: a shaft to rotate about a longitudinal axis; a rotor centrally secured to the shaft, the rotor having a body with a cylindrical surface extending between spaced ends; a rotor disk secured at each end of the rotor, each rotor disk secured at a center to the shaft; a housing encasing the rotor and the rotor disks and portions of the shaft within an internal cavity, the housing having interior end walls adjacent to, but spaced from, the corresponding rotor disks to form an end space therebetween, and an interior sidewall, with fluid inlet and fluid outlet ports in the interior sidewall, a first portion of the interior sidewall of the housing being cylindrical and curved with a constant radius over an angle of about approximately 180°, the first portion being spaced a constant distance from confronting portions of the cylindrical surface of the rotor, and a second portion of the interior sidewall of the housing extending between the extremities of the first portion of the interior sidewall, and a curvature of the second portion having a greater radius than a curvature of the first portion, the cylindrical surface of the rotor being proximal to the interior sidewall of the housing at a point between the fluid inlet and fluid outlet ports about midway along the second portion, the fluid inlet and fluid outlet ports being located in this second portion of the interior sidewall of the housing; two or more equally spaced, radially oriented slots in the rotor longitudinally extending across the cylindrical surface of the rotor body; two or more similar vanes, each vane having internal and external edges extending between sides, each vane slidably seated in one of said slots, each vane movable radially in the corresponding slot between an extended position with the external edge of the vane adjacent the interior sidewall 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 a vane positioned between the fluid inlet and fluid outlet ports; means associated with the vanes to enable the vanes to move to extended position; a plurality of slots in the rotor disks aligned with the rotor slots and slidably receiving the sides of the vanes; the rotor disks, the housing and the vanes constructed so that, during operation of the rotary piston pump, fluid entering the housing through the inlet port is carried by the rotor, in each of compartments formed between adjacent vanes, the rotor surface between the vanes, the rotor disks and the corresponding portions of the end walls and interior sidewall of the housing, until the adjacent vanes encompass the outlet port where the fluid is allowed to leave the housing, the end space between each of the corresponding housing end walls and rotor disks being provided with partitioned sections extending in a line between the fluid inlet and fluid outlet ports and dividing that end space into two or more sub-sections, the partition sections constructed so as to withstand pressure differentials between the sub-sections on either side of the partition sections.