# US 12,111,192 B2 · Magnetic-inductive flow meter and method for operating a magnetic-inductive flow meter > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 12,111,192 B2 - Document ID: US12111192B2 - Status: Granted - Kind: B2 - Application number: 17/628,602 - Filed: 2020-06-18 - Published: 2022-09-01 - Granted: 2024-10-08 - Earliest claimed: 2019-07-26 - Assignees: Endress + Hauser Flowtec AG - Applicants: Endress+Hauser Flowtec AG - Inventors: Simon Mariager - Web page: https://patentgrep.com/patent/US12111192B2 ## CPC - G01F 1/588: {combined constructions of electrodes, coils or magnetic circuits, accessories therefor} - G01F 1/60: Circuits therefor - G01N 11/00: Investigating flow properties of materials, e.g. viscosity, plasticity; Analysing materials by determining flow properties - G01N 2011/0026: {Investigating specific flow properties of non-Newtonian fluids} - G01F: MEASURING VOLUME, VOLUME FLOW, MASS FLOW OR LIQUID LEVEL; METERING BY VOLUME - G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q) ## Abstract A magnetic-inductive flow meter includes: a measuring tube for conducting a flowable medium, the measuring tube having a wall; at least three measuring electrodes arranged in the wall to form a galvanic contact with the flowing medium; a magnetic field-generating device for generating a magnetic field that passes through the medium; a measuring circuit designed to ascertain at least one first measurement variable, wherein measured values of the first measurement variable are ascertained at a first measuring electrode pair; and an analysis circuit designed to ascertain a Reynolds number and/or a kinematic viscosity value of the medium in the measuring tube using measured values for the first measurement variable and a second measurement variable, which differs from the first measurement variable, the measured values of the second measurement variable being ascertained at a second measuring electrode pair. ## Claims ### Claim 1 A magnetic-inductive flow meter, comprising: a measuring tube adapted to conduct a flowable medium and including a wall; at least three measuring electrodes disposed in the wall such that each measuring electrode is in galvanic contact with the flowing medium; at least one magnetic field-generating device configured to generate a magnetic field that passes through the measuring tube; a measuring circuit configured to determine at least one measurement variable, wherein measured values of a first measurement variable of the at least one measurement variable are determined at a first measuring electrode pair, which includes two measuring electrodes of the at least three measuring electrodes; and an analysis circuit configured to determine a Reynolds number and/or a kinematic viscosity value of the medium in the measuring tube using measured values of the first measurement variable and a second measurement variable, which differs from the first measurement variable, wherein measured values of the second measurement variable are determined at a second measuring electrode pair or at a third measuring electrode relative to a reference potential, and wherein the at least three measuring electrodes are arranged in the measuring tube such that, in a test measurement, quotients of current measured values of the first and second measurement variables correspond bijectively to the Reynolds number (Re) of the flowing medium in the measuring tube, at least within a Reynolds-number range of 1,000≤Re≤1,000,000. ### Claim 2 (depends on 1) The magnetic-inductive flow meter of claim 1, wherein the quotients of current measured values of the first and second measurement variables correspond bijectively to the Reynolds number (Re) of the flowing medium in the measuring tube, at least within a Reynolds-number range of 10,000≤Re≤100,000. ### Claim 3 (depends on 1) The magnetic-inductive flow meter of claim 1, wherein the at least three measuring electrodes are arranged substantially in a cross-sectional plane, wherein a first radius intersecting a second measuring electrode of the first measuring electrode pair and a second radius intersecting the third measuring electrode span an angle of at least 20°, wherein the measuring circuit is configured to determine measured values of the first measurement variable between the second measuring electrode and a first measuring electrode of the first measuring electrode pair and to determine measured values of the second measurement variable between the first and third measuring electrodes or at the third measuring electrode relative to the reference potential. ### Claim 4 (depends on 3) The magnetic-inductive flow meter of claim 3, wherein the angle spanning the first radius and the second radius is at least 40° but no more than 60°. ### Claim 5 (depends on 1) The magnetic-inductive flow meter of claim 1, wherein a first measuring electrode axis intersecting the first measuring electrode pair and a second measuring electrode axis intersecting the third measuring electrode and a fourth measuring electrode are substantially parallel, wherein the measuring circuit is configured to determine measured values of the first measurement variable between the first measuring electrode pair and to determine measured values of the second measurement variable between the third and fourth measuring electrodes. ### Claim 6 (depends on 1) The magnetic-inductive flow meter of claim 1, wherein, in a test measurement, the first measurement variable behaves substantially proportionally to a flow rate of the medium within a Reynolds-number range of 10,000≤Re≤1,000,000, and wherein, in the test measurement, a change in the second measurement variable within a Reynolds-number range of 10,000≤Re≤1,000,000 with increasing Reynolds number is not constant. ### Claim 7 (depends on 1) The magnetic-inductive flow meter of claim 1, wherein, in a test measurement, the medium is a Newtonian fluid, wherein, in the test measurement, the flow meter is introduced into a pipeline with a straight inlet section of at least DN 20 such that a substantially symmetrical flow profile is present in a measurement region, and wherein the measuring tube has a diameter of DN 80. ### Claim 8 (depends on 1) The magnetic-inductive flow meter of claim 1, wherein the magnetic field-generating device includes two oppositely attached coils that are connected in series in the same direction. ### Claim 9 (depends on 1) A method for operating a magnetic-inductive flow meter, the method comprising: providing a magnetic-inductive flow meter according to claim 1; detecting a measured value of the first measurement variable and a measured value of the second measurement variable, wherein the respective measured values of the first and second measurement variables are determined at different measuring electrode pairs; and determining a Reynolds number dependent upon the measured values of the first and second measurement variables. ### Claim 10 (depends on 9) The method of claim 9, further comprising calculating a corrected flow rate and/or a corrected volumetric flow using a correction factor, which depends upon the determined Reynolds number. ### Claim 11 (depends on 9) The method of claim 9, further comprising determining a kinematic viscosity value of the medium using measured values of the first or the second measurement variable and the determined Reynolds number. ### Claim 12 (depends on 9) The method of claim 9, wherein a map that assigns Reynolds numbers to quotients of the first and second measurement variables is bijective, at least within a Reynolds-number range of 1,000≤Re≤1,000,000. ### Claim 13 (depends on 12) The method of claim 12, wherein the map that assigns Reynolds numbers to quotients of the first and second measurement variables is bijective, at least within a Reynolds-number (Re) range of 10,000≤Re≤100,000. ### Claim 14 (depends on 9) The method of claim 9, wherein the first measurement variable is a corresponding potential difference of the first measuring electrode pair, and the second measurement variable is a corresponding potential difference of the second measuring electrode pair or of the third measuring electrode and the reference potential. ### Claim 15 (depends on 1) The magnetic-inductive flow meter of claim 1, wherein the first measurement variable is a corresponding potential difference of the first measuring electrode pair, and the second measurement variable is a corresponding potential difference of the second measuring electrode pair or of the third measuring electrode and the reference potential.