Temperature Measuring in Industrial Applications

The temperature of an object can be measured by direct contact or indirect by measuring the emitted energy of the object with non-contact infrared sensors.

Contact temperature Sensor:

  1. Thermocouples can measure the widest temperature span
  2. RTD are very repeatable and accurate
  3. Thermistors are the most accurate for a limited temperature span

A rudimentary temperature stick is sometimes used in the forging industry to determine if the forging has a certain temperature. This is not considered temperature measuring, because it only tells if the temperature is higher as the reaction temperature of the stick.

Non contact temperature Sensors:

All type of infrared sensors (also called Pyrometers, Spectral meters or Radiation meters). Click here to find out more about temperature measuring with infrared. Click here to find out more about selecting infrared wavelength.

Non Contact temperature measuring devices are still today a black box for most operators. Some reasons may be that infrared radiation is invisible to the human eyes. By the way: Did you know that rattlesnakes have small IR sensors under each eye which can sense the amount of heat emitted by a body?

Infrared sensors are either handheld or fix installed.

Handheld infrared temperature sensor

Handheld infrared thermometers do have limitations if the emissivity of the application is changing with temperature and therefore a frequent emissivity parameter change on the shop floor may not practical. Today you can purchase a handheld infrared temperature sensor for less than 100 dollars and this type of sensor may give satisfactory results depending on application. (But everytime I measure the temperature of my skin, I should be dead according to the sensor...)

Fix installed infrared temperature sensor

These type of sensor are far more sophisticated than handheld sensors. The biggest differences are in the optics, the advanced filtering capabilities, the options to include multi-wave length sensor technology and data-collection.

Williamson Gold Series 20 pyrometer

Williamson infrared temperature sensor