Page 533 - Dust Explosions in the Process Industries

500 Dust Explosionsin the Process Industries

are also given. Figure 7.24 illustrates a version of the Godbert-Greenwaldfurnace that
is in agreement with that being evaluated by the IECon the essentialpoints. Figure 7.25
shows a photograph of a Godbert-Greenwaldfurnace test.

DUST SAMPLE CHAMBER
\

HEAT RESISTANT

Figure 7.24 The Codbert-Creenwald furnace for determination of the minimum ignition tempera-
ture of dust clouds, a design produced by International Electrotechnial Commission (I 994).

Griesche and Brandt (1976) used a Godbert-Greenwaldfurnace modified in such a way
that dust clouds of known concentrationscould be passed through the furnace at a desired
constant velocity. They investigated the influence of the dust cloud velocity, or the mean
residence time of the dust in the furnace, on the minimum ignition temperature.The results,
given in Figure 7.26, show that the minimum ignition temperaturedecreased quite signif-
icantly with increasingresidence he. A conventionalGodbert-Greenwaldtest on the same