A thermocouple consists of two dissimilar metals, joined together at one end. When the junction of the two metals is cooled or heated a voltage is produced that can be correlated back to the temperature. Most thermocouple alloys are commonly available as wire.
Thermocouples are manufactured in different combinations of metals and/or calibrations. The calibrations most regularly specified by NSPI customers are J, K, T and E. High temperature calibrations include R, S, C and GB. Each calibration has a different temperature range and environment, although the maximum temperature varies with the diameter of the wire used in the thermocouple.
While the thermocouple calibration defines the temperature range, the maximum range will also be a factor the diameter of the thermocouple wire. Therefore, a very thin thermocouple may not reach the full temperature range.
Since thermocouples measure wide temperature ranges and are relatively rugged, they are very often used demanding industrial automation and process control applications. In selecting a thermocouple, the following criteria are key considerations:
- Temperature range
- Chemical resistance of the thermocouple or sheath material
- Abrasion and vibration resistance
- Installation requirements (may need to be compatible with existing equipment;existing holes may determine probe diameter)
NSPI manufactures a broad variety of thermocouple components and assemblies for use in virtually all high temperature, industrial and process temperature measurement applications. Today, NSPI thermocouples are among the most widely used in the world for applications such as forging, smelting and melting, heat treating, incineration and cogeneration, utility and waste boilers and multiple other severe use processes. Many of our assemblies are supplied in either drilled or flanged wells, and all assemblies can be supplied with our economical, head mount or DIN-rail mounted transmitters. If you can’t find a catalog thermocouple for your application, just contact us – custom versions can often be fabricated in less than a week!
Typical thermocouple applications
- Test stands
- Medical equipment
- Aerospace markets
- Packaging equipment
- Semiconductor processing
- Food processing equipment
- Heat treating and processing
- Engine and turbine exhaust gas
- Plastic injection molding machinery
|101 & 103||General purpose|
|201 & 203||With welded fittings|
|301||Spring loaded for use with cast iron explosion-proof housings|
|302||Spring loaded without transmitter for general purpose housing|
|305||Spring loaded, 1/2″ NPT hex hipple|
|312||Spring loaded (for use with type 1 general purpose head)|
|452||Spring loaded sanitary temperature sensor|
|3142B||Sanitary flush mount tank temperature sensor|
|3226A||Food piercing temperature sensor|
|3304A||Flexible stick-on surface temperature sensor|
|3312A||Autoclave temperature sensor|
|3332A||Embedded temperature sensors for rotating machinery and turbines|
|Bearing temperature||Sensors for the measurement of bearing temperatures|
|Bayonet fitting design||Spring loaded bayonet fitting temperature sensors|