Space heaters, toasters, dishwashers, electric ovens, and many other appliances involve the use of heating coils of various shapes, sizes and heat generation capacities.
Consumer and industrial ovens can be equipped with ceramic-coated heat coils, which affect heat generation and protect the coil from dripping grease or other hazards. Industrial dryers, clothing dryers, hair dryers and many other kinds of moisture removal and heat generation equipment are equipped with heating coils. Some furnace configurations employ a combination of heat coils and air blowers to heat air and then transmit it through ducts.
Heating coils are also very important to a large number of industrial equipment and processes. Metallurgical analyzers, plastic injection molding machines, holding tanks, paper processing equipment, oil reclamation equipment, blow molding machines, extruders, packaging equipment, bag sealing machines, hot stamping equipment, and labeling machines all can make use of heating coils.
Coil heating elements are available in many shapes and sizes. They can be bent to a custom size or shape, or they can be purchased in ready-made shapes; they can be round, coiled and spiral wound. Different shapes are appropriate in different situations. Spiral wound elements are useful in confined spaces. Star wound coils are placed in ducts and pipes in order to cause fluid turbulence.
Because of the wide variety of contexts in which coil heating elements are employed, a wide variety of coil configurations is necessary. Holding tanks, extruders, blow molding machines, bag sealing and hot metal forming punches all use coil heaters, and each requires its own special coil configuration.
Operating on AC voltages, coil heaters provide a uniform heat pattern over a wide area at temperatures of up to 1200°F. They can be annealed and made of brass, aluminum, copper, iron nickel or steel with ceramic, fiberglass or mica insulation. Depending on the metal, some coil heaters are corrosion resistant and may be immersed in heated substances or used in cryogenic applications.
Correctly pairing coil heating elements with their applications is essential to the safety and effectiveness of those applications.