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Mineral Insulated Thermocouples

The mineral insulated thermocouple is a durable industrial temperature sensor. It's sturdy construction encapsulates a matched pair of thermocouple elements inside a stainless steel or nickel based alloy sheath. The sheath material is more durable than wire coverings. It is impervious to most liquids and gases and will withstand high external pressures. The sheath is available in various diameters (see simplex and duplex sheath tables). The larger sizes insure that it can endure usage in abusive industrial environments.

The mineral insulated thermocouple elements are held in place by Magnesium Oxide (MgO). This enables it to be used in an environment with temperatures up to 2200°F (1200°C). The elements are of various ANSI types (J, K, T, E, N, R and S) depending on the temperature range being measured (see TC type table). Normal accuracy is achieved with standard limits material. Applications requiring high precision can be ordered with "special limits" material.

Hot end terminations on our mineral insulated thermocouples can be chosen among grounded junction (G), ungrounded junction (U), exposed junction (E), or reduced tip (R).

The benefits of mineral insulated thermocouples are:

  • Durable. This type of construction helps to overcome bending, twisting, and compaction stresses in more difficult industrial environments.
  • Survive high temperatures. Suitable sheath materials are available to handle unfavorable environmental conditions such as corrosive atmosphere and extremely high temperatures.
  • Metal sheaths are impervious to most liquids and gasses
  • Sheath makes possible the ability to withstand high external pressures
  • Radiation resistance achieved through the correct choice of components


Mineral insulated thermocouples are used in a variety of temperature measurement applications. Eustis Co./Pyrocom thermocouples are used in applications including aerospace, automotive, power generation, primary metals, food industry, pulp & paper, industrial processing, heat treating, and OEM manufacturing.