Patent ID: 8647089

Claim:
A pump comprising: a pump body defining an interior space having a first cavity and a second cavity, and the pump body also defining an inlet chamber and an outlet chamber, an input passage opening into the inlet chamber, and an output passage opening from the outlet chamber, a first rotor rotatably supported in the first cavity and for rotating about a first axis, the first rotor having n vanes (n greater than one) projecting radially therefrom in equiangularly spaced relationship about the first rotor, the vanes having tips whereby during rotation of the first rotor the tips of the vanes pass in effective sealing relationship with a bounding surface of the first cavity that extends at least 360/n degrees about said first axis, a second rotor rotatably supported in the second cavity, whereby during rotation of the second rotor, the second rotor is in effective sealing relationship with at least a portion of the bounding surface of the second cavity, and wherein the second rotor defines n recesses therein in equiangularly spaced relationship about the second rotor, wherein the first and second rotors are disposed between the inlet chamber and the outlet chamber and the first and second rotors are in effective sealing relationship with each other during rotation of the rotors, a drive transmission mechanism coupled to the first and second rotors for rotating the rotors in opposite directions at equal angular velocities so that during a complete revolution of the first rotor each vane successively emerges from a recess of the second rotor, passes the inlet passage and the outlet passage, and enters a recess of the second rotor, while the inlet chamber remains effectively sealed from the outlet chamber, where each of said recesses is effectively sealed from said inlet chamber and said outlet chamber for all of said complete revolution.