Open hearth furnaces are the the furnaces where excess carbon and other impurities are burnt out of Pig iron to produce Steel. Since steel is difficult to manufacture due to its high melting point normal fuels and furnaces were insufficent, and the open hearth furnace was developed to overcome this difficulty. This furnace operates at a high temperature by using regenerative preheating of fuel and air for combustion. In regenerative preheating, the exhaust gases from the furnace are pumped into a chamber containing bricks, where heat is transferred from the gases to the bricks. The flow of the furnace is reversed so that fuel and air pass through the chamber and are heated by the bricks. Through this method, a open-hearth furnace can reach temperatures high enough to melt steel.
