Method for calibration, and measurement and analysis method

Patent metadata

Field	Value
Publication number	US-12153025-B2
Application number	US-201716482937-A
Country	US
Kind code	B2
Filing date	Oct 13, 2017
Priority date	Feb 2, 2017
Publication date	Nov 26, 2024
Grant date	Nov 26, 2024

Abstract

A method for a multistep analysis of a measuring program of a portable gas measuring device includes performing a factory setting of the portable gas measuring device, connecting a container having a known gas standard and performing a reference measurement, wherein a multidimensional reference measurement is recorded, selecting a measuring program for target materials from a list on the device, performing a measurement on a sample in dependence on the selected measuring program, wherein a multidimensional measured variable is recorded, automatically performing an analysis to identify at least one of the one or more target materials in the sample and the respective concentrations thereof, wherein the analysis is based on the multidimensional measured variable from the measurement on the sample, the multidimensional reference measurement for the gas standard, the values for the plurality of target materials or measuring programs, and the factory setting for the portable gas measuring device.

First claim

The invention claimed is:

1. A method for a multistep calibration of a portable gas measuring device having a detector unit for gas chromatography for selective detection of a plurality of chemical compounds that is connected to a control unit and an analysis unit, the method comprising:
performing a two-part calibration comprising:
in a first part of the two-part calibration that is performed in a factory, performing a factory setting of at least one of the portable gas measuring device and a device associated with the portable gas measuring device and generating a database that comprises values for a plurality of target materials and/or values for a plurality of measuring programs for the portable gas measuring device, and
in a second part of the two-part calibration that is performed by at least one user in the field, connecting at least one container having a known gas standard to the portable gas measuring device by the at least one user and performing a reference measurement on the known gas standard, wherein a multidimensional reference measurement is recorded,

selecting, by the at least one user in the field, a measuring program for one or more target materials from a list of measuring programs that were installed on the device by a producer or prepared by the at least one user, the measuring program being a controlled sequence of measuring,
performing a measurement by the portable gas measuring device on a sample, wherein the control unit executes the measuring program in dependence on the selected measuring program, wherein a multidimensional measured variable is recorded,
automatically performing an analysis by the analysis unit to identify at least one of the one or more target materials that is present in the sample and the respective concentrations thereof, wherein the analysis is based on:
the factory calibration for the portable gas measuring device and the values for the plurality of target materials and/or the values for the plurality of measuring programs from the first part of the two-part calibration,
the multidimensional reference measurement for the gas standard from the second part of the two-part calibration, and
the multidimensional measured variable from the measurement on the sample, and

repeating the second part of the two-part calibration by the at least one user in the field prior to performing at least one subsequent sample measurement by connecting the at least one container having the known gas standard to the portable gas measuring device by the at least one user and repeating the reference measurement on the known gas standard.

2. The method of claim 1 , wherein performing the factory setting comprises determining separate device correction values for the portable gas measuring device and stored in a database.

3. The method of claim 1 , wherein the gas measuring device is a gas chromatograph that is a portable measuring device for field tests of less than 1.5 kg total weight.

4. The method of claim 1 , wherein the gas standard is a gas mixture having one or more harmless materials that are not harmful to health or are present in harmless concentrations, as defined by a workplace safety standard, and at least one of the one or more target materials in the sample is a health-hazardous material in a hazardous concentration in the sample, as defined by the workplace safety standard.

5. The method of claim 1 , wherein a gas mixture of the materials isobutene in harmless concentration, as defined by a workplace safety standard, and toluene in harmless concentration, as defined by the workplace safety standard, is used as the gas standard for the reference measurement, wherein the one or more target materials of the selected measuring program of the sample measurement are benzene and 1,3-butadiene, wherein a detection limit of the portable gas measuring device of at least one of the benzene and 1,3-butadiene is less than 1 ppm, and wherein signal components of further unknown materials in the measurement signal can also be differentiated from signal components of the target materials in the analysis.

6. The method of claim 5 , wherein the concentration of at least one of the isobutene and the toluene is between 1 ppm and 100 ppm in air or nitrogen.

7. The method of claim 1 , wherein the portable gas measuring device is equipped with or connected to a mobile processing unit, which can access databases of external processing units via a wireless connection.

8. The method of claim 7 , wherein additional data processed during the analysis are retrieved from external databases by the portable gas measuring device.

9. The method of claim 1 , wherein the portable gas measuring device stores multidimensional measured variables of successive measurements in a database and carries out a function test of the portable measuring device from the reference measurement, and one or more items of information are displayed to the at least one user about the state of the portable gas measuring device based on the function test.

10. The method of claim 9 , wherein the one or more items of information comprises a warning about required maintenance.

11. The method of claim 1 , wherein the portable gas measuring device incorporates prior measurement results, which were also generated using the selected program, from an internal database in the analysis.

12. The method of claim 1 , wherein the portable gas measuring device incorporates measurement results, which were also generated using the selected program by other portable gas measuring devices of the same type, from an internal or external database in the analysis.

13. The method of claim 1 , wherein the measuring program is automatically adapted to measurement results of one or more auxiliary detectors.

14. The method of claim 13 , wherein the measurement results of one or more auxiliary detectors comprises an external temperature.

15. The method of claim 1 , wherein the portable gas measuring device automatically proposes changes to the measuring program to the at least one user that have been computed in an algorithm from prior measurements stored in databases as parameters.

16. The method of claim 1 , wherein during the analysis, after a preceding pass of the analysis has been evaluated as failed according to specific criteria, subsequently further target materials are added from a database into the analysis, which supplement the measuring program selected by the at least one user, wherein the addition of further target materials to the analysis is repeated until either:
the analysis becomes successful, or
at least one of: a specific number of repetitions is exceeded and a time span is exceeded.

17. The method of claim 1 , wherein a measuring program for multiple target materials is selected and a control program for the measurement, an algorithm of the analysis, or both is automatically adapted so that a known cross sensitivity for the multiple target materials is avoided.

18. The method of claim 1 , wherein the measurement on the sample is carried out in parallel by multiple users, and the selection of the measuring program, data, or both are transferred between multiple portable gas measuring devices-connected in a network, to a central server or both.

19. The method of claim 1 , wherein the portable gas measuring device is used as a part or an attachment on at least one of a vehicle and an aircraft and the gas measuring device is connected via a wireless connection to an external processing unit.

20. The method of claim 19 , wherein the at least one

Assignees

• Draeger Safety Ag & Co Kgaa

Inventors

• Schmittmann Matthias
• Weber Johannes
• Weber Paul
• Jünemann Arne

Classifications

• G01N2030/025

  Gas chromatography · CPC title

• G01N33/0062

  concerning the measuring method or the display, e.g. intermittent measurement or digital display · CPC title

• G01N33/0021

  involving the use of a carrier gas for transport to the sensor · CPC title

• G01N33/0006

  Calibrating gas analysers · CPC title

• G01N2030/042

  Standards · CPC title