Patent ID: 6871539

Claim:
An oscillating piston volumetric fluid meter having a cylindrical measuring chamber comprising: a lateral wall, a bottom and a lid, a lower cylinder and an upper cylinder having the same diameter, which is less than the diameter of said chamber, an inlet orifice and an outlet orifice for respectively admitting fluid to and evacuating fluid from said chamber, a cylindrical piston disposed eccentrically and guided kinematically in said chamber and effecting an oscillatory movement in said chamber as a result of the displacement of a volume of fluid, a fixed partition between said inlet orifice and said outlet orifice, lying radially between said lateral wall and said lower and upper cylinders, and lying axially between said bottom and said lid; and a vertical groove extending at least partly along said lower and upper cylinders and in communication with one of said inlet and outlet orifices, said groove being situated in the vicinity of said fixed partition.