US Patent 7086649 Gasket with two concentric lips

A gasket, sliding about the axis of rotation of a part to be brought closer to or to be spaced apart from another part with which it provides tightness through a pair of lips provided on a ring. The gasket includes a portion of the ring capable of bending to modify the clearance between the corresponding lip and the part, the pressure prevailing in an intermediate cavity, the balance of forces on the joint and hence the clearance and the leak flow rate allowed before the gasket, which is advantageous in particular in a case of ventilation gas for refrigerating an element of the machine in controlled operating conditions.