open hearth

/ˈoʊpənˌhɑrθ/
adjective
  1. Relating to a type of steelmaking furnace that uses a shallow hearth and regenerative heating.
    • Many old steel plants used open-hearth furnaces before switching to basic oxygen furnaces.
    • The open-hearth method was once the dominant way to produce steel.
    • The open-hearth process requires careful control of temperature and chemistry.
What does "open hearth" mean? | whatsthatwordmean | whatsthatwordmean