Author: Herbert Romaro
A furnace is a mechanical device designed, constructed, and used to generate heat (i.e. a heater). Depending on what kind is being used, a furnace serves to either heat the interior of a structure to prevent unwanted cold from ensuing, or to burn materials for the purpose of molding or cremating. Different kinds of furnaces include household furnaces, metallurgical furnaces, industrial furnaces, and incinerators.
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Different Kinds of Furnaces
Household Furnaces, used to disperse cold from within a structure and provide hot water, have several different means of production and require any one of a variation of fuel sources: natural gas, fuel oil, coal, or wood.
The two most common household furnaces are combustion and condensation. The first kind requires an exhaust and relies on burning fuel to generate heat. The second recycles heat by extracting it from the exhaust gases. This kind, being acidic, is designed to prevent corrosion and has a condensate pump to remove any water buildup that will occur.
Heat distribution also has different means. If the means of heat distribution require water or steam, the mechanical device generating the heat is commonly referred to as a boiler. Many modern furnaces in the United Stated, however, use forced-air heat. Convection, or air distribution, directs cold air into a heating chamber and then blows it out through a system of ductwork into the structure.
Metallurgical furnaces create heat for several purposes: smeltering, reducing iron ore to pig iron, steelmaking, and remelting and molding metal. Where blast furnaces are used to reduce iron ore into pig iron, various kinds of steelmaking furnaces are made for a multitude of other purposes: Puddling furnace, reverberatory furnace, Bessemer converter, open hearth furnace, basic oxygen furnace, electric arc furnace, electric induction furnace. Each of these treats metal in a different way based on its intended purpose. Needless to say, all metallurgical furnaces require extreme temperatures to successfully perform their respective functions.
Industrial furnaces, usually immense, are also call direct fired heaters. These furnaces have a couple different purposes: providing heat for a production process or serving as a reactor. These furnaces are uniquely designed, depending on each furnace's intended function, heating manner, type of fuel, and method of air combustion, but they all have common features, namely mechanisms that, when working together, produce heat. Typically, fuel is fed into a burner and is converted into heat via blasts of air blown in by an air blower. Combustion takes place in a firebox, radiating heating fluid through a series of tubes where it achieves its desired temperature. Flue gas, generated through combustion, leaves the firebox, but the convection section recovers more heat from the exhaust before discharging through the smokestack.
Incinerating furnaces, or incinerators, typically are used to burn, or cremate, waste. This kind of furnace can be categorized as an industrial furnace due to its size, productive function, and the fact that industrial plants use incinerators to minimize their waste. Where incinerators are different than other industrial furnaces, however, is that they don't assist in actual production; they only destroy waste. Their manner of fuel and performance, though, are the same as other industrial furnaces.
Furnaces are amazing devices, but they must be respected at all times. People who don't respect such power, or don't know how to properly use it, are liable to get burned!