Thermocouple for high temperatures and harsh environments

The OMC Aeropak Great features a thick wall mineral insulated (MI) thermocouple cable, which is suitable for use in harsh, high-temperature process environments such as incinerators, heat treatment furnaces and industrial ovens, as well as for measuring the temperature of molten metals. Units can also be supplied with a hard coating such as cement or Stellite for improved resistance in other harsh high-temperature applications, including heavy oil, pulverised coal-firing furnaces, cement kilns and dispersion kneaders used in the mixing of plastics or rubber.

With Aeropak Great, the gap between the element and the thick wall sheath is densely filled with high-purity magnesium oxide (MgO) to prevent any residual air from penetrating the sheath. This enables faster response times compared with conventional standard thermocouples. Cable lengths of up to 10m can be specified.

Manufacturing process

Chris Chant, Business Development Manager at Okazaki Manufacturing Company, comments: "Aeropak Great is manufactured using OMC's special cold drawn technology, which enables such long lengths of high-quality cable to be produced. The thermocouple element is protected by the thick wall sheath and high-purity magnesium oxide, which enables the product to withstand severe conditions, providing excellent corrosion and heat resistance."

Aeropak Great is supplied in large diameters with a very thick-walled sheath (up to 22mm outside diameter), providing high resistance to vibration and impact shocks. These thermocouples are said to perform very well in bright annealing furnaces and carburisation ovens, where Ta (tantalum) wires are added to Hoskins 2300 material; the selective oxidation rate of Type K thermocouple wire when exposed to H2 gas can be reduced significantly. When combined with a silicon nitride protection tube, the Aeropak Great is able to withstand the very high temperatures associated with molten metal applications.

Supplied with an easy-to-use terminal head, the Aeropak Great is suitable for a wide range of temperature sensors and RTDs.

For more information on OMC's Aeropak Great range of thermocouples, go to www.okazaki-mfg.co.uk.