Patent ID: 9556870
Date: 2017-01-31
CPC Classifications: F01C,F04C,F05C

Claim:
1. A sliding vane pump assembly for providing positive displacement of a fluid, the pump assembly comprising: a housing having a fluid inlet and a fluid outlet formed therein; a lining member received in the housing and defining a substantially cylindrical inner surface; a rotor arranged inside the lining member to rotate about a rotational axis, the rotor defining a substantially cylindrical outer surface, the inner surface of the lining member and the outer surface of the rotor defining a working space therebetween, the working space having a radial cross-sectional area which varies about the rotational axis; a plurality of vanes received in substantially radial slots formed about the outer surface of the rotor, each of the vanes being arranged to slide in a radial direction with respect to the rotor such that an outer edge of the vane contacts the inner surface of the lining member, thereby dividing the working space into working chambers, and first and second bearing members received in the housing and arranged at either end of the rotor, the bearing members defining end walls of the working chambers; wherein rotation of the rotor draws the fluid from the fluid inlet into the working chambers and ejects the fluid from the working chambers into the fluid outlet, and wherein base portions of the slots formed in the rotor are in fluid communication with each other continuously throughout each revolution of the rotor, wherein the fluid communication is provided by a substantially circular groove formed in at least one of the end faces of the rotor and end faces of the bearing members; and wherein, in use of the pump assembly, the total volume of fluid under the vanes and in the substantially circular groove is substantially constant, so that there is a flow of fluid between the slots to equalize the pressure under the vanes; and wherein when the vane is urged in the radially inwards direction by direct contact of a radially outer face of the vane with the lining member, the increased pressure underneath the vane is transmitted through the groove to assist in urging another vane to move in the radially outwards direction.