Optical Emission Spectroscopy of Cadmium Dominated Discharges Applied for Assessment of Explosion Protection

Authors

  • R. Methling Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany
  • S. Franke Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany
  • C. Uber Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
  • B. Barbu Technische Universität Ilmenau, Gustav-Kirchhoff-Str. 1, PF 100565, 98684 Ilmenau, Germany
  • F. Berger Technische Universität Ilmenau, Gustav-Kirchhoff-Str. 1, PF 100565, 98684 Ilmenau, Germany
  • M. Hilbert Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
  • D. Uhrlandt Leibniz Institute for Plasma Science and Technology (INP), Felix-Hausdorff-Str. 2, 17489 Greifswald, Germany

DOI:

https://doi.org/10.14311/ppt.2023.1.47

Keywords:

optical emission spectroscopy, cadmium, explosion protection

Abstract

An assessment for the safe use of electrical equipment in explosive atmospheres can be performed with the aid of a spark test apparatus. Therefore, an anodic tungsten wire with 200 µm diameter is moved along the surface of a rotating cadmium disc (cathode). The explosion chamber enclosing the electrodes is filled with a highly explosive mixture of hydrogen and air. Depending on surface topology and relative movement of the contact pair, discharges occur randomly.
A model contact device is used to investigate the plasma properties and the discharge characteristics near the thermo-chemical ignition threshold of the explosive atmosphere that typically occur at voltages around 30V and currents around 30mA.
Spectroscopic investigations reveal that the emission of the discharges is dominated by atomic lines of cadmium, which allow the determination of distribution temperatures.

References

International Electrotechnical Commission. IEC 60079-11, Explosive atmospheres. Part 11: Equipment protection by intrinsic safety. IEC, Geneve, Switzerland, 2011.

V. Babrauskas. Ignition handbook. Fire Science Publishers, Issaquah (WA), USA, 2003. ISBN 978-0-9728111-3-2.

R. Eckhoff and W. Olsen. A new method for generation of synchronized capacitive sparks of low energy. J. Electristatics, 68:73–78, 2010.

S. Essmann. Experimentelle Untersuchung der Zündung durch elektrostatische Entladungen geringer Energie. PhD thesis, Karlsruher Institut für Technologie (KIT), 2019. ISBN 978-3-95606-445-6. doi:10.7795/110.20190709.

M. Hattwig and H. Steen, editors. Handbook of Explosion Prevention and Protection. Wiley VCH, Weinheim, 2008. ISBN 9783527612475.

U. Johannsmeyer. Zündung explosionsfähiger Gemische durch kurzzeitige Schliessfunken in kapazitiven Stromkreisen für die Zündschutzart Eigensicherheit. PhD thesis, TU Braunschweig, 1984.

C. Uber. Charakterisierung elektrischer Kontakt-Entladungen im Bereich niedriger Spannungen im Zündgrenz-Bereich von Wasserstoff-Luft-Gemisch. PhD thesis, TU Ilmenau, 2019. www.db-thueringen.de/receive/dbt_mods_00039103.

Z. Zborovszky and L. Cotugno. Evaluation of the Cadmium Disc Breakflash in testing Electrical Circuits. A Comprehensive Study of Intrinsic Safety Criteria. Bureau of Mines Open File Report. Denver Research Institute, University of Denver, 1974.

C. Uber, T. Runge, J. Brunzendorf, et al. Electrical discharges caused by opening contacts in an ignitable atmosphere. Part II: Spectroscopic investigation and estimation of temperatures. J. Loss Prevention in the Process Industries, 61:213–219, 2019. doi:10.1016/j.jlp.2019.05.010.

R. Shekhar, S. Gortschakow, H. Grosshans, et al. Numerical investigation of transient, low-power metal vapour discharges occurring in near limit ignitions of flammable gas. J. Phys. D Appl. Phys., 52(4):045202, 2019. doi:10.1088/1361-6463/aaed04.

J. W. Olesik and G. M. Hieftje. Optical imaging spectrometers. Anal. Chem., 57(11):2049–2055, 1985. doi:10.1021/ac00288a010.

W. Lochte-Holtgreven. Evaluation of Plasma Parameters. American Institute of Physics, New York, 1995. ISBN 9781563963889.

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Published

2023-08-08

Issue

Vol. 10 No. 1 (2023)

Section

Articles

License

Copyright (c) 2023 R. Methling, S. Franke, C. Uber, B. Barbu, F. Berger, M. Hilbert, D. Uhrlandt

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