Patent ID: 7574925

Claim:
A fluid metering system comprising: a cylindrical rotor having a channel completely through the rotor with opposing openings at each end of the channel configured to allow a fluid to flow within the channel, the rotor configured and arranged to receive a torque for rotation; a piston disposed within the channel, wherein the piston is configured and arranged for slidable movement within the channel between a first position substantially blocking one opening of the channel and a second position substantially blocking the other opposing opening of the channel, wherein the movement of the piston is in response to a fluid pressure differential at the opposing ends of the channel; and a chamber housing having an interior configured and arranged to receive the rotor, the chamber housing further having first and second lateral openings configured and arranged to allow flow of a fluid through the interior during rotation of the rotor within the chamber as the piston reciprocates within the rotor channel between the first and the second positions.