Godbert-Greenwald furnace

It is categorically assumed that dusts ignited in the laboratory by a spark source are an explosive hazard in the industry. However, some dusts that do ignite with a spark source are also shown to present a hazard by the Godbert-Greenwald furnace test and by experience... 

The minimum ignition temperature of a powder layer can also be measured in a Godbert-Greenwald furnace apparatus designed basically for dust/air mixtures (see below). 

Ignition temperature of a powder layer can also be measured in a Godbert-Greenwald furnace modified as follows the top fitting is removed and an air inlet orifice is attached to the bottom mounted on a locking plate. The powder sample is placed in a container 25 mm dia. and 13 mm in depth made of stainless steel gauze. The container is suspended in the centre of the furnace and its temperature is measured... 

The handling (drying, transportation) of explosive powders is often performed under an inert atmosphere. Because of economic considerations, air is not completely excluded but is diluted by Ng or CO2 to an O2 concentration insufficient for dust explosion. The maximum permissible oxygen concentration to prevent ignition in a dust cloud is measured in a Hartmann tube or in a Godbert-Greenwald furnace by spraying the powder with the test gas mixture instead of air. 

Ignition temperatures in the Godbert - Greenwald furnace and explosion characteristics measured by the Hartmann apparatus with plastics and other powders... 

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