Arc-induced flame transmission

Figure 6.157 Block diagram of the apparatus for investigations on arc-induced flame transmission according to [56],...

A quite different effect is an arc-induced flame transmission through the joints of a flameproof enclosure. To avoid any misunderstanding these joints do comply with the d-standards and they have been shown to be safe by type testing for the corresponding explosion subgroup and test gas-air mixture. Investigations covering this field have been published in [35] and [56]. 

Figure 6.158 Arc-induced flame transmissions. Gap w versus arc peak power Nz at the moment of flame transmission.

A very different result has been obtained using aluminium electrodes (Fig. 6.160). There is no correlation safe gap versus arc peak power, but a chaotic distribution of flame transmissions down to very small gap values. This indicates a real particle-induced flame transmission and has been proven by evaluating the films of camera no. 1 the aluminium particles entering the indication chamber act as a very effective ignition source. 

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