Apparatus and method for the non-destructive determination of the content of the magnetizable and/or non-magnetizable portion of a sample

Patent metadata

Field	Value
Publication number	US-11536692-B2
Application number	US-201716323209-A
Country	US
Kind code	B2
Filing date	Aug 2, 2017
Priority date	Aug 2, 2016
Publication date	Dec 27, 2022
Grant date	Dec 27, 2022

Abstract

An apparatus and method for the non-destructive determination of the content of the magnetizable and/or non-magnetizable portion of a sample, in which the sample is provided in an air gap of a magnetically conductive yoke, an alternating magnetic field is generated by an alternating magnetic field strength of an excitation coil in the yoke, and first measurement data relating to the sample are collected using a measuring device which is inductively coupled to the yoke, and comparing the first measurement data to second measurement data relating to a reference sample, wherein the same alternating magnetic field strength or the same alternating magnetic field is applied to both the reference sample and the sample and the difference between the two collected sets of measurement data is included as a measure in the determination of the content for the magnetizable and/or non-magnetizable content portion of the sample.

First claim

The invention claimed is:

1. A method for the non-destructive determination of the content of the magnetizable and/or non-magnetizable portion of a sample, comprising:
providing the sample in an air gap of a magnetically conductive yoke;
generating an alternating magnetic field B using an alternating magnetic field strength H of an excitation coil in the yoke;
collecting first measurement data relating to the sample using at least one measuring device which is inductively coupled to the yoke; and
determining the magnetizable and/or non-magnetizable content portion in the sample by comparing the first measurement data to second measurement data relating to a reference sample that has a known magnetizable and/or non-magnetizable content portion,
wherein during the collection of the first and second measurement data relating to the sample and the reference sample with the aid of the excitation coil, either:
the same alternating magnetic field strength H is applied to both the reference sample and the sample, in which case a difference between the two collected sets of measurement data based on the different magnetic fields B of the reference sample and the sample is included as a measure in the determination of the content for the magnetizable and/or non-magnetizable content portion of the sample,
or
the same alternating magnetic field B is applied to both the reference sample and the sample, in which case a difference between the two collected sets of measurement data based on the different magnetic field strengths H of the reference sample and the sample is included as a measure in the determination of the content for the magnetizable and/or non-magnetizable content portion of the sample.

2. The method according to claim 1 , comprising measuring the alternating magnetic field B using the at least one measuring device with a measuring coil that is inductively coupled to the excitation coil via the yoke.

3. The method according to claim 1 , wherein when determining the content portion of the magnetizable and/or non-magnetizable portion in the sample, the relative permeability of the sample and the reference sample are determined.

4. The method according to claim 1 , wherein a relative permeability of the sample is modeled as a sum of relative permeabilities of pure iron and air.

5. The method according to claim 1 , comprising applying the same alternating magnetic field strength H to the sample and the reference sample by regulating a coil current of the excitation coil.

6. The method according to claim 1 , comprising applying the same alternating magnetic field B to the sample and the reference sample by regulating said alternating magnetic field B.

7. The method according to claim 1 , wherein during the collection of the first and second measurement data, an operating point of the alternating field strength H lies in a region of a flat curvature of a magnetic permeability of the yoke.

8. An apparatus for carrying out the method for the non-destructive determination of the content of the magnetizable and/or non-magnetizable portion of a sample according to claim 1 , the apparatus comprising:
the first magnetically conductive yoke that has the first air gap for selectively receiving the sample or the reference sample;
the excitation coil provided on the yoke;
the at least one measuring device inductively coupled to the yoke;
an evaluation device connected to the at least one measuring device, for determining the content of the magnetizable and/or non-magnetizable content portion of the sample;
a first measuring coil, which is inductively coupled to the yoke, from which the at least one measuring device collects the first measurement data;
a regulating device that cooperates with the excitation coil in order to apply the same alternating magnetic field strength H or the same alternating magnetic field B in the first air gap for the reference sample or the sample; and
a differential circuit for generating difference data from the first measurement data relating to the sample and the second measurement data relating to the reference sample;
wherein the evaluation device is connected to the differential circuit for determining the content of the magnetizable and/or non-magnetizable content portion in the sample as a function of the difference data.

9. An apparatus for carrying out the method for the non-destructive determination of the content of the magnetizable and/or non-magnetizable portion of a sample according to claim 1 , the apparatus comprising:
the first magnetically conductive yoke that has the first air gap for receiving the sample;
a first measuring coil inductively coupled to the first yoke;
a second magnetically conductive yoke that has a second air gap for receiving the reference sample;
a second measuring coil inductively coupled to the second yoke;
the excitation coil inductively coupled to both of the first and second yokes;
the at least one measuring device that collects first and second measurement data from the first and second measuring coils;
a differential circuit connected to the at least one measuring device for generating difference data from the measurement data relating to the reference sample and the sample; and
an evaluation device connected to the differential circuit for determining the content of the magnetizable and/or non-magnetizable content portion in the sample as a function of the difference data.

10. An apparatus for carrying out the method for the non-destructive determination of the content of the magnetizable and/or non-magnetizable portion of a sample according to claim 1 , the apparatus comprising:
the magnetically conductive yoke that has a middle piece and two side legs adjoining the middle piece, each with the respective air gap, wherein a first air gap is embodied for insertion of the sample and a second air gap is embodied for insertion of the reference sample;
at least one of the excitation coils provided on the middle piece of the yoke and having at least one first and second measuring coil that are provided on each of the two side legs and are inductively coupled to the yoke;
the at least one measuring device that collects measurement data from the first and second measuring coils;
a differential circuit connected to the at least one measuring device for generating difference data from the measurement data relating to the reference sample and the sample; and
an evaluation device connected to the differential circuit for determining the content of the magnetizable and/or non-magnetizable content portion in the sample as a function of the difference data (WHO.

11. The apparatus according to claim 9 , wherein the differential circuit for generating difference data electrically connects the first and second measuring coils in series.

12. The apparatus according to claim 8 , wherein during the collection of the first and second measurement data, an operating point of the alternating field strength H of the excitation coil lies in a region of a flat curvature of a magnetic permeability of the yoke.

13. The apparatus according to claim 10 , wherein the differential circuit for generating difference data electrically connects the first and second measuring coils in series.

14. The apparatus according to claim 9 , wherein during the collection of the first and second measurement data, an operating point of an alternating field strength of the excitation coil lies in a region of a flat curvature of a magnetic permeability of the yokes.

15. The apparatus according to claim 10 , wherein during the collection of the first and second measurement data,

Assignees

• Voestalpine Stahl Gmbh

Inventors

• Schuster Stefan
• Gstöttenbauer Norbert
• Thaler Christoph
• Wöckinger Daniel

Classifications

• G01R33/1223

  Measuring permeability, i.e. permeameters (G01R33/14 takes precedence) · CPC title

• G01R33/045

  in single-, or multi-aperture elements · CPC title

• G01N27/72 Primary

  by investigating magnetic variables · CPC title

• G01R33/04

  using the flux-gate principle · CPC title