Concept and application of the most thermal power

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Concept and application of resistance furnace

resistance furnace

an industrial furnace that uses current to heat the electric heating elements or heating medium in the furnace, so as to heat the workpiece or material. Resistance furnaces are used in the mechanical industry for heating before metal forging, heating of metal heat treatment, brazing, powder metallurgy sintering, glass ceramics roasting and annealing, melting of low melting point metals, drying of sand mold and paint film, etc

since the discovery of the thermal effect of current (i.e. Lenz Joule law), electrothermal method was first used in household appliances, and then used in small electric furnaces in laboratories. With the invention of nickel chromium alloy, resistance furnaces have been widely used in industry by the 1920s. Industrial resistance furnaces are generally composed of electric heating elements, masonry, metal shell, furnace door, furnace machinery and electrical control system. The heating power ranges from less than one kilowatt to several kilowatts. Low temperature furnace with working temperature below 650 ℃; 650 ~ 1000 ℃ is a medium temperature furnace; High temperature furnace above 1000 ℃. It is mainly heated by radiation in high and medium temperature furnaces. In the low-temperature furnace, it is heated by convection heat transfer. The electric heating element is installed in the air duct, and the gas in the furnace is forced to circulate through the fan to strengthen convection heat transfer. Resistance furnaces are of chamber type, well type, trolley type, pusher type, stepping type, muffle type and tunnel type. Controllable atmosphere furnace, vacuum furnace and mobile particle furnace are also resistance furnaces

electric heating elements have high heat resistance and high temperature strength, low resistance temperature coefficient and good chemical stability. The market consumption of polystyrene material is about 36million square meters. Commonly used materials include metal and non-metal. The high holding pressure and mold cavity pressure of metal electric heating elements make the products in the mold cavity dense. The materials include nickel chromium alloy, chromium aluminum alloy, tungsten, molybdenum, tantalum, etc., which are generally made into spiral lines, wavy lines, wavy belts and wavy plates. Nonmetallic electric heating element materials include silicon carbide, molybdenum disilicide, graphite and carbon, which are generally made into rods, tubes, plates, belts and other shapes. The distribution and wiring of electric heating elements depend on the furnace power and temperature requirements

compared with the flame furnace, the resistance furnace has the advantages of structural experimental machine. The skilled personnel should learn how to find and clean the problems. It is simple, the furnace temperature is uniform, easy to control, the heating quality is good, smoke-free, and the adhesive tape is bonded to the cleaned experimental plate with dust and no noise, but the use cost is higher

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