firebeds

Noun

firebed (plural firebeds)

1. A layer of fuel that burns under a heat source
   • Another factor of great importance in everyday service is the degree to which the gas/steam ratio is influenced by growing firebed resistance, and this is again a matter in the hands of the designer if he kbows what to do about it. [...] poorer grades of coal require more air per unit of heat...1962 April, “Letters to the Editor: The Giesl oblong ejector”, in Modern Railways, page 286