Abstract: An improved water-cooled, liningless cupola wherein the lower portion of the water-cooled body section, including the high heat area above the tuyeres, tapers inwardly toward the bottom with the taper terminating a short distance above the tuyeres and with the remainder of the bottom end of the body section, which includes the tuyere area, being either cylindrical or outwardly tapered. Preferably, the cylindrical or outwardly tapered bottom end portion plus an upper adjacent section of the inwardly tapered lower portion are provided with a multiplicity of interiorly projecting studs which serve to anchor the initial refractory lining and, thereafter, skull after it is formed.

Abstract: An improved cupola furnace waste gas recuperative system and method for collecting waste furnace gases, cleaning them for the purpose of safely burning same either in a recuperator-heat exchanger for preheating incoming furnace blast air or for other heating purposes. The improvement consists of a method and means to control the pressure inside of the gas take-off chamber of an open, top charged, cupola furnace for the purposes of preventing gases from escaping through the charging hopper, preventing the indraft of excessive amounts of air, preventing explosive combustion and flashback of the waste gas and maintaining cleaning efficiency at any gas flow rate. Means include the controlled recirculation of a variable portion of the waste gas through part of the gas cleaning system and control of the furnace top gas pressure as a function of the incoming cupola furnace blast air.