MASS FLOWMETER OF THE CORIOLIS TYPE

• US 20080148868A1
• Filed: 03/07/2008
• Published: 06/26/2008
• Est. Priority Date: 05/02/2005
• Status: Active Grant

• Current Assignee: Berkin B.V.
• Original Assignee: Berkin B.V.
• Inventors: Lotters, Joost Conrad, Mehendale, Aditya, Zwikker, Jan Marinus
• Granted Patent: US 7,464,610 B2
• Time in Patent Office: Days
• US Class Current: 73/861.355
• CPC Class Codes: G01F 1/8422 exciters
• CPC Class Codes: G01F 1/8427 detectors
• CPC Class Codes: G01F 1/8431 electronic circuits
• CPC Class Codes: G01F 1/8472 having curved measuring conduits, i.e. whereby the measuring conduits' curved center line lies within a plane G01F1/8481 takes precedence
• CPC Class Codes: G01F 1/8486 with multiple measuring conduits

Abstract

A mass flowmeter of the Coriolis type with a tube through which a medium flows during operation and with excitation elements for causing the entire tube or part thereof to perform a rotational vibration about a primary axis of rotation during operation. The excitation elements are electromagnetic and do not make contact with the tube during operation and have no components that are fastened to the tube. More The tube is made of an electrically conducting material, and the excitation elements include first members for causing an electric current to flow through the tube during operation and second elements for generating a magnetic field at the area of a portion of the tube. The magnetic field is perpendicular to the direction of the current and in operation either the current or the magnetic field changes its sign periodically.

Claims

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 7 wherein the excitation means in operation do not make contact with the tube and have no components that are fastened to the tube,

wherein the excitation means generate two magnetic fields, each acting on a portion of the tube, in order to achieve a Lorentz force torque excitation of the tube or tube portion about the excitation axis.

2. 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, wherein the excitation means in operation do not make contact with the tube and have no components that are fastened to the tube,

wherein the excitation means comprise a magnet yoke the sensing tube being U-shaped and the magnet yoke having two air gaps through which opposite portions of the U-shaped tube extend, in order to achieve a Lorentz force torque excitation of the tube or tube portion about the excitation axis.

3. A mass flow meter as claimed in claim 2, wherein the magnet yoke is energized by a permanent magnet accommodated in the magnet yoke.

4. A mass flow meter as claimed in claim 3, wherein the magnet yoke has an upper leg remote from the air gaps and in that the permanent magnet is accommodated in the center of the upper leg.

5. A mass flow meter as claimed in claim 2, wherein the U-shaped tube has two lateral arms, and in that the excitation is on the lateral arms of the U-shaped tube.

6. A mass flow meter as claimed in claim 2, wherein the U-shaped tube has two lateral arms, and in that the excitation is on the bends of the lateral arms of the U-shaped tube.

7. 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, wherein the excitation means in operation do not make contact with the tube and have no components that are fastened to the tube, wherein the excitation means comprises a magnet yoke which is adapted to function as a torque generator for the sensing tube.