Band Heaters
Band heaters are thin, circular electric heaters which clamp around cylinders, pipes and nozzles to provide direct or radiant heating. Similar in construction and application to strip heaters, band heaters are used mainly in plastic and metal forming processes, particularly extrusion. Available in a virtually limitless range of widths, diameters, thicknesses, sealing capabilities and clamping options, band heaters, also known as "knuckle heaters" and "barrel heaters", provide direct heating up anywhere between 300º and 1400ºF. Tubular band heaters are wider, covering a wider surface area to provide higher heat to cylinders or nozzles with smaller diameters. Heater bands are generally appreciated for their quick, easy clamp-on installation and for how quickly they produce heat. While band heaters usually provide direct conductive heating to substances such as plastic and polymer-metals, they may be used for convectional air heating as well.
Heating is an essential element of nearly all extruding processes, since the process depends upon the molten plasticity of the material being extruded. Band heaters provide direct, efficient heat in cramped and oddly shaped areas where other types of heaters would not be effective. Such applications include plastic injection molding, plastic extruding, metal injection molding, blown film extruding, front end extrusion heating, wire processing, chemical and food processing. Band heaters are sometimes employed as baseboard heaters to provide indoor heating. Insulation materials in band heaters are the same as those used in strip heaters: mineral, mica and ceramic. Mineral insulated heater bands with stainless steel construction are capable of reaching the highest temperatures, heating up to 1400ºF. Mica band heaters range the lowest, between 300º and 800ºF, while ceramic band heater temperatures can reach 1200ºF.