Patent ID: 7311077
Filing Date: 2007-12-25
Classification: F01C,F04C

Abstract:
1. A rotary positive displacement machine comprising: a casing having a circular cylindrical internal surface delimiting an operating chamber; an orbiting piston in the operating chamber, the orbiting piston being mounted so as to orbit about a chamber axis which is the axis of the internal surface, the orbiting piston comprising a non-rotating outer part and a rotating inner part, the outer part having a circular cylindrical external surface, the chamber axis passing through the orbiting piston, a generatrix of the external surface being adjacent to the internal surface, and a diametrically opposite generatrix being spaced from the internal surface; a vane member mounted on the casing, the vane member having a tip face which faces the external surface of the orbiting piston and which has a length substantially equal to that of the orbiting piston; and a linkage which connects the vane member to the orbiting piston so as to keep the tip face of the vane member adjacent the external surface of the orbiting piston; wherein at least one of the external and internal surfaces is provided with individual compliant strips which are distributed around the one surface, run parallel to one another, and project above the one surface, from respective grooves in the one surface, the distribution of the compliant strips being such that there is at least one of the compliant strips in contact with the other surface over the majority of the orbit of the orbiting piston.