US Patent 7614861 Rotary fluid-driven motor with sealing elements

A static-fluid-pressure-driven rotary motor includes a casing, which defines a chamber having a fluid inlet and a fluid outlet, and at least one rotor assembly rotatably mounted within the casing. The rotor assembly includes a rotor, a plurality of barrier elements associated with, and extending outwards from, the rotor, and a resilient seal associated with at least an outer edge of each of the barrier elements. As the rotor turns about its axis of rotation, the outer edges of the barrier elements passing in proximity to a facing wall of the casing chamber against which the resilient seals for a sliding seal while accommodating variations in clearance between the outer edge of the barrier element and the facing wall of the casing.