Ceramic bands are made of an electrical resistance helical coil, which is inserted around a series of interlocking steatite bricks of 1100°c having physical and die electric strength and good thermal conductivity, covered with 4mm insulation and then wrapped in sheet metal. The resistance wire that converts electrical energy to thermal energy is a nickel-chromium alloy of 80% nickel normally termed as Ni-Chrome. The sheet metal is stainless steel ( chrome – nickel) for temp upto 700°c.
Mica bands are made of an electrical resistance ribbon or wire, which is wound around a mica winding card and sandwiched between two sheets of mica, then wrapped in sheet metal. The resistance wire or ribbon that converts electrical energy to thermal energy is normally a nickel-chromium alloy of either 80% nickel which is useful to 1100°C or 60% nickel which is useful to 950°c. The mica is, most often, one of three types: muscovite, useful to 500°c, phlogopyte, useful to 750°c, and synthetic mica, useful to 900°c. The sheet metal is normally either mild steel, stainless steel, brass, GI depending on the temp and the product to be heated. The maximum temp for mica band heater is 400°c.
Energy Saving band heaters are ideally manufactured to reduce the time taken to heat the barrel and reduce the energy cost, with optimized heating. In addition to the in built 4mm thick heat saving insulation an extra 12mm – 25mm thick flexible insulation is added on the external sheath covered with an additional metal layer. The power saving on these heaters ranges between 25 – 40% depending on the insulation thickness selection.