The design of high-temperature cartridge heaters positions a nickel-chrome resistance wire precision wound around a magnesium oxide core. It is then inserted into a stainless or Incoloy tube, placing the resistance wire close to the sheath. The core is centrally placed within the tube and filled with magnesium oxide powder. Nickel pins pass through the centre of the core making contact with the resistance wire at both ends. The whole assembly is highly compacted by a swaging operation and thus offering excellent heat transfer to the external sheath, allowing for operating temperatures to 1600ºF and high watt densities. One end of the heater is closed with a welded metal end-disc and wire leads exit at the opposite end which is typically closed with a lava seal.
A variety of wire leads and lead protection options are available. Heaters can be supplied with built-in thermocouples, mounting fittings and many other options. Contact us today for more information about our cartridge heaters.