Fuel Fired, Heat Treating Furnaces
Heat treating furnaces are systems used to heat air in a chamber for the purpose of tempering, hardening, drawing, annealing materials for industries such as aircraft, machine tool, automotive, military, mobile equipment, ceramic, steel and many other. These systems can be electric or fuel gas & oil fired. These systems typically consist of an insulated metal housing, one or more burners, high temperature re-circulating blowers, access, exhaust fan and control panel to monitor oven temperature and safety limits.
Heat treatment processes are classified by temperature of treatment, furnace atmosphere and pressure. The heat treating industry is directly related to the metal producing and secondary processing industries. Heat treatment is needed to cause desired changes in the metallurgical structure and hence the properties of metal parts. The major heat treating processes are for iron, steel, ferrous-alloys, glass and other nonferrous metals. Ferro-alloys, particularly steels, undergo the most dramatic changes in properties.
Generally, the most stable steel structures are produced when steel is heated to a high temperature and then slowly cooled. This is called annealing or normalizing. The process of heat treatment performs multiple functions as are needed for individual cases. In some cases, it releases stress, strain and fatigue so that the material will work normally, in other cases it alters the structure so that the material's properties will improve. As an example, parts made from glass and some ceramic cannot be used without proper annealing, they will simply shatter under residual stress. All of these functions are carried out in heat treating furnaces of various kinds, shapes and sizes.
Temperature uniformity throughout the heating chamber is the goal in the design and operation of high temperature, heat treating furnaces. These systems can range in size from large platform mounted single burner furnaces too huge multiple burner lear type furnaces. Gas fired furnaces have definite advantages: Lower initial cost, Lower operating costs
Gas burners not only eliminate the need for replacing expensive heating elements, but also require only a minimum of maintenance.
Oven operation can be batch or continuous process. Most heat treat furnaces are pre-assembled and factory calibrated to minimize installation cost and ensure uniform temperature throughout the oven. Fuel trains for gas & oil fires ovens consist of UL, FM or CSA agency listed discrete manual shutoff valves, pressure regulators and automatic fuel shutoff valves.
Warm air furnaces are systems used to heat air in residential homes, commercial buildings, institutions, schools, hospitals, and industrial facilities to name a few. The systems are generally fired by natural gas, propane, or fuel oil. The systems typically consist of an atmospheric burner, heat exchanger, circulating fan, draft hood, and fuel train. The burner draws combustion air in from either the surrounding area or from an outside source. The fuel and air burn, thus forming combustion gases, which give up heat across a heat exchanger. The heat is then exhausted to the outside through a vent. A draft hood isolates the burner from outside pressure fluctuations by pulling varying quantities of heated facility air into the exhaust. A circulation fan passes facility air from the return ducts over the furnace heat exchanger. The warmed air then flows into the ductwork for distribution around the facility.
Fuel trains consist of UL, FM, or CSA agency listed combination shutoff valves with integral regulator for residential systems. Larger commercial & industrial systems use discrete manual shutoff valves, pressure regulator and automatic fuel shutoff valves.