Effect of rusting and mechanical damage of gap surfaces on efficiency of flame gaps in flameproof electrical apparatus

Electrical apparatus in industry for use in the presence of explosive gases must be specially designed to prevent the apparatus from igniting the gas. In the case of flameproof enclosures, any holes and gaps in the enclosure wall must be sufficiently long and narrow to prevent hot combustion products expelled by a gas explosion inside the enclosure from igniting an external explosive cloud. There are tight requirements as to the maximum permissible gap surface roughness. This article describes an experimental study of the influence of severe mechanical and corrosive damage of flame gap surfaces on gap performance for IIB and IIC gases in air, using ethylene and hydrogen as test gases. In agreement with previously published findings for propane (IIA gas), it appeared that even with ethylene and hydrogen gap surfaces can suffer considerable damage without this causing any reduction of gap performance. © 2013 American Institute of Chemical Engineers Process Saf Prog 33: 49–55, 2014

Section: Introductionmentioning

confidence: 85%

“…A gap assembly before rusting is shown in Figure 5. Further details can be found in Opsvik et al [5], Grov et al [6], Solheim et al [7] and Eckhoff et al [4].…”

Section: Apparatus and Experimental Methodsmentioning

confidence: 99%

Is the safe performance of flame gaps in flameproof electrical apparatus deteriorated by rusting and mechanical damage? Part 2: Group IIB and IIC gases

Arntzen

Ringdal²,

Steiner³

et al. 2013

“…To investigate this, two thermocouples were mounted in the secondary chamber at two different distances downstream of the flame gap exit. The details are given by Solheim et al [3]. Table 2 summarizes the results.…”

Section: Three Main Series Of Experiments With Rectangular Grooves Inmentioning

confidence: 98%

“…, and Solheim et al . . A more detailed but unpublished presentation of the content of this article was given by Eckhoff et al .…”

Section: Introductionmentioning

confidence: 99%

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Is the safe performance of flame gaps in flameproof electrical apparatus deteriorated by rusting and mechanical damage? Part 1: Group IIA gases

Eckhoff

Arntzen

Opsvik

et al. 2012

Electrical apparatus in industry for use in the presence of explosive gases must be specially designed to prevent the apparatus from igniting the gas. In the case of flameproof enclosures, any holes and gaps in the enclosure wall must be sufficiently long and narrow to prevent transmission of a possible gas explosion inside the enclosure to an external explosive cloud. Furthermore, there are tight requirements to the maximum permissible gap surface roughness. This article describes an experimental study of the influence of mechanical and corrosive damage of flame gap surfaces on gap performance for IIA gases in air, using propane as test gas. It was found that, contrary to common presumptions, gap surfaces can suffer considerable damage without this causing any reduction of gap performance. In some cases, significant mechanical surface damage in fact improves gap performance. © 2012 American Institute of Chemical Engineers Process Saf Prog 32: 49–56, 2013

Stress analysis due to internal explosion pressure of designed flameproof enclosure for hazardous area

Ahirwal

Prasad

Kashyap

et al. 2019

Flameproof (Ex d) enclosures are constructed in such a way that an internal ignition of a flammable atmosphere will not be transmitted outside the enclosure and thereby preventing the ignition of surrounding flammables. The large Ex d enclosure was designed for gas group IIB explosive atmosphere with the help of MATLAB and ANSYS software and further a study of stress analysis due to internal pressure had been carried out on the plates and cover by keeping the thickness of body plate and cover constant. The study showed that stress was observed more in the center of the plate and reducing toward the edges of plates. The value of the length and breadth ratio (a/b) was found out with the help of the curve fitting method to calculate maximum stress (σmax) in the designed Ex d enclosure. The calculated maximum stress of all the plates was less than the simulated results, so the simulated results indicated that the designed enclosure is within the safety limit and suitable for hazardous area.