Type K Mineral Insulated Thermocouple — Plain Pot Seal, Leaded

Summary: Type K (NiCr–NiAl) thermocouple built to IEC Class 1 tolerance with AISI 310 stainless-steel sheath, mineral insulation (MgO), insulated (ungrounded) hot junction, and PFA-insulated lead. The flexible MI sheath can be bent and formed on site. The plain pot seal provides a compact, leak-tight cable exit.

How It Works (brief)

A thermocouple measures temperature via the voltage generated at the junction of two dissimilar metals. The measuring (hot) junction contacts the process; the reference junction is held at a known temperature. The resulting millivolts are converted to temperature using standard reference tables (Seebeck effect).

Insulated (Ungrounded) Junction

The hot junction is electrically isolated from the metal sheath, reducing electrical interference and improving reading stability. Response time is slightly slower than grounded types but measurement is more stable in noisy environments.

Mineral Insulation (MI)

The sheath is densely packed with magnesium oxide (MgO) to:

• Isolate conductors from each other and from the sheath,

• Promote fast heat transfer and quick response,

• Increase mechanical robustness while allowing field formability,

• Enhance durability against corrosion and harsh environments.

Technical Details

• Type: K (NiCr–NiAl), single element

• Tolerance: IEC Class 1

• Sheath: AISI 310 stainless steel

• Junction: Insulated (ungrounded)

• Exit: Plain pot seal

• Lead: PFA insulation with resistance to oils, acids, and many chemicals; flexible with good mechanical strength

• Pot seal temperature limit: max. 180 °C (standard design)

Note: Protect the pot seal from elevated ambient temperatures. Alternative gland/exit solutions are available for higher temperature requirements.

Key Benefits

• High-temperature capable 310 SS sheath

• Noise-resistant readings via insulated junction

• Flexible, bend-to-fit MI sheath for tight installs

• PFA lead for chemical resistance and long service life

• Reliable under high vibration and demanding conditions

Typical Applications

• Heat exchangers, power generation

• Brick/cement kilns, heat-treatment and annealing furnaces

• Thermostats and process control

• Food probes/thermometers, automotive diagnostics

• Laboratories and R&D

• High-pressure and vacuum systems, high-vibration environments

Custom Options

Probe diameter, immersion length, lead length, and connector/termination options can be tailored to your application. Engineering support available for special builds.