open-hearth

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open-hearth

A. gas and air enter B. pre-heated chamber C. molten pig iron D. hearth E. heating chamber (cold) F. gas and air exit (Precision Graphics)

1. Designating or being a reverberatory furnace used in the production of high-quality steel.
2. Of or relating to the steel produced in such a furnace.

Hearth, usually sited clear of the walls, without a chimney-stack or hood above it, therefore requiring a femerall, lantern, or louvre on the roof.