Because they are inexpensive, interchangeable, and can measure a wide range of temperatures, thermocouples are the most common type of industrial temperature sensor used today. A thermocouple is a junction between two different metals that produces a voltage related to a temperature difference. Different metal alloys are used for different temperature ranges and different applications.

Thermocouples are widely used in science and industry; applications include temperature measurement for kilns, gas turbine exhaust, diesel engines, and other industrial processes.
Types of thermocouples:

  • Type K (chromel-alumel) thermocouples are the most common general purpose thermocouple with a sensitivity of approximately 41 µV/°C. They are inexpensive, and a wide variety of probes are available in its −200 °C to +1350 °C range.
  • Type E (chromel–constantan) has a high output (68 µV/°C) which makes it well suited to cryogenic use. Additionally, it is non-magnetic.
  • Type J (iron–constantan) has a more restricted range than type K (−40 to +750 °C), but higher sensitivity of about
    55 µV/°C.[2]
  • Type N (Nicrosil–Nisil) (Nickel-Chromium-Silicon/Nickel-Silicon) thermocouples are suitable for use at high temperatures, exceeding 1200 °C, due to their stability and ability to resist high temperature oxidation. Sensitivity is about 39 µV/°C at 900 °C, slightly lower than type K. Designed to be an improved type K, it is becoming more popular.
  • Types B, R, and S thermocouples use platinum or a platinum–rhodium alloy for each conductor. These are among the most stable thermocouples, but have lower sensitivity than other types (10 µV/°C) and a higher cost.

Integrity Calibration Services sells thermocouples for many industry applications. All you need is to answer a few simple questions from us about your particular process and we will help find a solution or help build a custom thermocouple sensor assembly that fits your process perfectly. It might include connection heads, thermowells and/or transmitters or other temperature sensor accessories depending on your needs.

One other point to note is that Integrity Calibration Services is a calibration lab. This means that we are able to test and calibrate your thermocouples completely before they even enter your facility. Our technical staff has over 70 years of experience calibrating temperature devices with uncertainties as low as +-(0.05C).