Patent ID: 7479000

Claim:
A pump comprising: a casing; a driving rotor that is supported for rotation within the casing, the driving rotor having a plurality of teeth, each of the plurality of teeth having a leading convex surface and a trailing surface; and a plurality of driven rotors coupled to said driving rotor and supported for rotation within the casing, each of said plurality of driven rotors having an inlet port and a discharge port and a plurality of teeth, each of the plurality of teeth having a leading surface and a trailing flat surface; wherein the driving rotor and the plurality of driven rotors are positioned in the casing such that, as the driving rotor and the plurality of driven rotors rotate, the plurality of teeth of the driving rotor and the respective pluralities of teeth of the driven rotors are interfaced with one another to form a seal between the inlet port and the discharge port of each driven rotor, the seal being formed only between the leading convex surfaces of the teeth of the driving rotor and the trailing flat surfaces of the teeth of the driven rotors.