Patent ID: 6520029
Filing Date: 2003-02-18
Classification: G01F,G01P

Abstract:
A device for measuring a gas flow or a gas mixture flow moving in a flow channel (7) in a given direction, said device comprising:a frame (10) comprising a measuring space (8), a rotatable single tubular measuring duct (6) mounted on the frame and having a first end extending into the flow channel and a second open end disposed in the measuring space, said duct having at least one sidewall orifice formed near the first end of the duct and exposable to the gas flow as the measuring duct rotates in the flow channel to develop a pressure in the measuring duct and an open second end to pass the pressure generated by the gas flow from the measuring duct into the measuring space, and a measuring element (1) mounted on the frame and positioned to measure the varying pressure generated in the measuring duct as the measuring duct rotates in the gas flow, said measuring element being disposed near the second end (9) of the measuring duct, wherein the measuring duct is disposed in a substantially perpendicular orientation relative to the direction of the gas flow, wherein the measuring duct is rotatable about the longitudinal axis of the measuring duct, and the measuring duct comprises a first sidewall orifice (4), which is disposed at the first end (2) of the measuring duct and faces alternately in the direction of flow and against the flow as the measuring duct rotates to create a changing and cyclic pressure wave in the measuring duct, characterized in that the measuring duct comprises a second sidewall orifice (3), which is disposed in that part of the measuring duct which extends into the measuring space to equalize the pressure in the measuring space and the pressure in the measuring duct.