Patent ID: 6887057

Claim:
A method of increasing the pressure of a fluid comprising the steps of: retrieving a rotor set comprising a first and second rotor that are mounted about an axis of rotation that is offset from being colinear and the rotors having a top dead center location and a bottom dead center location where the each rotor has a first set of vanes and a second set of vanes where the first set of vanes have engagement surfaces that are located in the longitudinally forward location of each rotor and the engagement surfaces of the vanes of the opposing first and second rotors are adapted to engage one another only at the top dead center location, the rotors each further comprising a second set of vanes where each vane has an engagement surface where opposing vane of the second set of vanes on the first and second rotor is only in engagement at the bottom dead center location, the volume between the first and second rotors defines chamber regions, positioning the rotors in a casing where the casing has an inner surface that engages an outer surface of the rotors at the bottom dead center and top dead center locations where a first lateral surface of the casing defines an inlet port and a second lateral surface defines an outlet port, providing communication from the inlet port to the fluid and rotating the rotors so the chamber regions in communication with the inlet port are expanding, passing the fluid past the top dead center location where two adjacent engaged enagement surfaces of opposing vanes of the first set of vanes for the first and second rotors and the inner wall of the casing creates a seal from the outlet port and the inlet port and discharging a portion of the fluid to the outlet port and two adjacent engaged enagement surfaces of opposing vanes of the second set of vanes for the first and second rotors and the inner surface of the casing at the bottom dead center location further provides a seal from the outlet port to the inlet port.