Thermocouples are fabricated by joining together two electrical conductors, each made of different metal alloys. This junction generates a small millivolt signal that changes with temperature. The signal is sent to an electronic device, which is used to display and/or control the temperature. The most common calibrations for thermocouples are types J, K, and T.
Soft Wire Construction
This is the most economical construction, and the most basic. It is used where the insulation on the lead wire provides enough protection for the application. A soft wire thermocouple is usually supplied with an exposed junction to give a fast response time.
Tube and Wire Construction
This type of sensor offers low-cost construction for a wide range of applications up to 900°F (482° C).
A metal tube is used to provide additional protection to the thermocouple junction, which is located at the tip.
The standard 304 stainless steel tube is available in 1/8-in., 3/16-in, and 1/4-in. diameters.
Mineral Insulated Construction
This type of sensor offers a more rugged, shock-resistant construction for higher operating temperatures. It is flexible enough to be bent around a mandrel to a radius of twice the outside diameter of the sheath.
A compressed mineral insulated powder, usually magnesium oxide (MgO), is used to insulate and protect the wires inside a metal sheath. The sheath material is selected to provide the best corrosion resistance for your application.
- Mineral insulated thermocouples manufactured with a molded transition that endures intensive use.
- Diameters available from 0.02 to 0.375-in.
- Grounded, ungrounded, and exposed tips available.
- Smallest transition size in the industry.
- The molded transition’s low expansion co-efficient and moisture-resistant capabilities are excellent for exposure to liquids.