MAGNETIC-INDUCTIVE FLOW METER AND METHOD FOR OPERATING A MAGNETIC-INDUCTIVE FLOW METER

摘要

The invention relates to a magnetic-inductive flow meter which can be inserted into a pipe through which a medium flows, said flow meter comprising: a housing, wherein the housing has a housing wall; at least one first and one second measurement electrode which form a galvanic contact with the flowing medium and are positioned on the housing wall; at least one magnetic field-generating device for generating a magnetic field which passes through the housing wall, wherein the magnetic field-generating device is positioned in the housing and comprises a measurement circuit which is designed to determine at least one first measurement variable, and wherein measurement values of the first measurement variable are measured between two measurement electrodes or at a measurement electrode in relation to a reference potential, in particular an earth potential. The flow meter is characterised in that: an evaluation circuit is designed to determine a Reynolds number and/or a kinematic viscosity value of the medium in the pipe by means of measurement values of the first measurement variable and of a second measurement variable which differs from the first measurement variable, wherein the measurement values of the second measurement variable are measured between two measurement electrodes or at a measurement electrode in relation to a reference potential, in particular an earth potential; and the measurement electrodes are positioned on the housing wall in such a way that, during a test measurement, quotients of current measurement values of the first and of the second measurement variable correspond bijectively with the Reynolds number of the medium in the pipe.