Electromagnetic flow sensor

• Main Author: ZINGG THOMAS
• Format: Patent
• Language: English
• Published: 10.01.2006
• Subjects: MEASURING; MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUIDLEVEL; METERING BY VOLUME; PHYSICS; TESTING

The flow sensor serves to measure an electrically conductive fluid flowing in a pipe. It comprises a flow tube designed to be inserted into the pipe for conducting the fluid, the flow tube being electrically nonconductive at least on a fluid-contacting inner side, an electrode arrangement consisting of at least two measuring electrodes disposed on the flow tube for picking up a voltage induced in the fluid, and a magnetic field system likewise disposed on the flow tube. The magnetic field system comprises at least two saddle-shaped field coils for producing a magnetic field cutting the fluid during operation of the flow sensor, a respective ferromagnetic pole piece for each of the two field coils, as well as at least one ferromagnetic return path extending around the flow tube upstream of the two field coils and at least one ferromagnetic return path extending around the flow tube downstream of the two field coils for directing the magnetic field around the flow tube. The pole pieces are magnetically coupled to the return paths by means of ferromagnetic coupling elements. Each of the, preferably identically shaped, coupling elements has at least one essentially trough-shaped cover segment which receives a first winding section of the respective associated field coil, lying essentially on a first periphery of the flow tube, or a second winding section of the associated field coil, lying essentially on a second periphery of the flow tube.