Gas curtain ventilation control for open hooded ferroalloy furnace

Claim 1

An electric smelting furnace system comprising in combination a. an electric smelting furnace pot, open at the top end thereof; b. a hood above the furnace pot and spaced therefrom to provide unobstructed access to the top of the furnace pot for charging and/or stoking, and for admitting ambient air for oxidizing or ventilating furnace off-gases, said hood acting to collect the hot gaseous furnace products containing entrained solid particles and induced air derived from the atmosphere surrounding the furnace and admitted through the said unobstructed access; c. a solid particle collection system connected to receive the gaseous products collected by said hood, said collection system being of limited volumetric capacity for separating solid particles from the hot gaseous furnace products and induced air, prior to discharge of same into the atmosphere, said collection system being subject by its construction to certain temperature limits; d. means for projecting a continuous annular curtain of gas in a downwardly path partially across the unobstructed access area between said furnace pot and said hood, to thereby limit the volume of air induced from the atmosphere surrounding the furnace to an amount sufficient to provide substantially complete combustion of the oxidizable gaseous furnace products and reduce the temperature of the gases to be processed through said collection system, without exceeding the capacity of the collection system.