Patent ID: 7353718
Filing Date: 2008-04-08
Classification: G01F

Abstract:
1. A mass flowmeter of the Coriolis type with a sensing tube through which a medium flows during operation and with excitation means for causing the entire tube or part thereof to oscillate about an excitation axis of rotation during operation, wherein the excitation means are (electro)magnetic and in operation do not make contact with the tube and have no components that are fastened to the tube, wherein the tube is manufactured from an electrically conducting material, and the excitation means comprise first means for causing an electric current to flow through the tube wall during operation and second means for magnetic field generation, wherein the second means provide two oppositely directed magnetic fields located at some distance from one another, each formed by two magnet poles located opposite one another between which an air gap is present, a portion of the tube is passed through each said air gap, with either the current or the magnetic fields changing their sign periodically during operation, such that a torque excitation of the tube arises in operation, resulting in an oscillatory rotation of the tube or tube portion about the excitation axis of rotation.