Patent ID: 8683975

Claim:
An apparatus comprising: a first rotor having a cavity therein defined by first and second inner side walls and by an inner perimeter wall, the first rotor mounted so as to rotate about a first axis; a second rotor having an outer face, first and second sides, a slot formed in a region of the outer face, and a seal contained within the slot, the second rotor mounted so as to rotate about a second axis parallel to and offset from the first axis; a shaft fixed relative to the second rotor and mounted so as to rotate about an axis coincident with the second axis; a blade fixed to the inner perimeter wall and to the first and second inner side walls, a portion of the blade extending into the slot and the seal, and wherein a portion of the second rotor rests within the cavity, and the outer face is configured for rolling contact with the inner perimeter wall; and a plurality of limited radial extension swing seals, wherein each of the swing seals comprises a first end coupled to the outer face of the second rotor, and comprises a second end biased away from the outer face of the second rotor and toward the inner perimeter wall of the first rotor.