Method for defect detection for the signal line between an electrode and a measuring- and/or evaluation unit of a magneto-inductive flow measuring device

Patent metadata

Field	Value
Publication number	US-10408646-B2
Application number	US-201515537906-A
Country	US
Kind code	B2
Filing date	Dec 10, 2015
Priority date	Dec 22, 2014
Publication date	Sep 10, 2019
Grant date	Sep 10, 2019

Abstract

A method for defect detection for a signal line between an electrode and a measuring- and/or evaluation unit of a magneto-inductive flow measuring device having at least one measuring- and/or evaluation unit, as well as a measuring tube with at least two measuring electrodes and a third electrode, comprising steps as follows:
A) ascertaining a ratio of at least two measured electrical impedances between the measuring electrodes and/or between at least one of the two measuring electrodes and the third electrode; B) comparing the impedance ratio with a desired value range and C) outputting a defect report, when the impedance ratio exceeds or subceeds the desired value range, and a magneto-inductive flow measuring device.

First claim

The invention claimed is:

1. Method for defect detection for a signal line between an electrode and a measuring and/or evaluation unit of a magneto-inductive flow measuring device having at least one measuring and/or evaluation unit, as well as a measuring tube with at least two measuring electrodes and a third electrode, wherein the third electrode is an EPD electrode, by means of which complete filling of the measuring tube with a measured medium is monitored during the measuring, comprising steps as follows:
A) ascertaining a ratio of at least two measured electrical impedances, a first of the two measured electrical impedances being between the measuring electrodes and a second of the two measured impedances being between at least one of the two measuring electrodes and the EPD electrode,
wherein the measuring of the impedances occurs by applying a voltage with a plurality of frequencies to a preresistor on a measuring path composed of two of the measuring electrodes and to a measuring path composed of at least one of the measuring electrodes and the EPD electrode;

B) comparing a ratio of the electrical impedances measured in step A with a desired value range, and
C) outputting a defect report when the impedance ratio exceeds or subceeds the desired value range.

2. Method for defect detection as claimed in claim 1 , wherein the desired value range lies between 0.2 and 5.0.

3. Method for defect detection as claimed in claim 1 , wherein the defect report indicates a signal line break when the highest one of the impedances trends approximately toward infinity.

4. Method for defect detection as claimed in claim 1 , wherein impedance ratios of at least three measured impedances between each of the measuring electrodes and the EPD electrode are ascertained and compared with the desired value range.

5. Method for defect detection as claimed in claim 1 , wherein the magneto-inductive flow measuring device has a ground electrode.

6. Method for defect detection as claimed in claim 1 , wherein the magneto-inductive flow measuring device further includes a ground electrode and at least three impedances between, in each case, one of three of the two measuring electrodes, the EPD electrode, and the ground electrode are measured and evaluated by ratio formation and reconciliation with the desired value range.

7. Method for defect detection as claimed in claim 1 , wherein the magneto-inductive flow measuring device includes an operating mode for performing steps A, B, and C.

Assignees

• Flowtec Ag

Inventors

• Spahlinger Andre
• Rufenacht Markus
• Boeglin Christophe

Classifications

• G01F1/588 Primary

  combined constructions of electrodes, coils or magnetic circuits, accessories therefor · CPC title

• G01F1/60

  Circuits therefor · CPC title

• G01F1/584 Primary

  constructions of electrodes, accessories therefor · CPC title

• G01F1/586

  constructions of coils, magnetic circuits, accessories therefor (G01F1/582 takes precedence; magnet; inductances; transformers; selection of materials for their magnetic properties per se H01F) · CPC title

• G01F25/10

  of flowmeters · CPC title