Monday, February 27, 2017

Industrial Temperature Sensors and Indicators

Variety of electrical temperature sensors
Variety of electrical temperature sensors (Pyromation)
Temperature sensors are vital to everyday products and in the manufacturing of just about every product we use. Household ovens, refrigerators, and air conditioners all depend on temperature control to function properly and temperature control is essential in all process industries such as chemical, power, refinery, food processing, telecom, cement, fertilizer, pull & paper, plastics and petro-chemical.

Temperature sensors are devices which are used to temperature measurement of a medium (i.e. liquid, solid or gas). The sensor detects change in the temperature, and accordingly, change its physical or electrical property in a manner that can be measured. These sensors come in many different forms and are used for a wide variety of applications.

We as human’s simply sense temperature as hot or cold, but in process control, precise measurement of temperature is required in order to control a process efficiently. Accordingly, the correct temperature sensing device needs to be properly selected.

Types of Temperature Sensors

vapor actuated temperature indicator
Vapor actuated temperature indicator (REOTEMP)
Mechanical temperature sensors and indicators:

Devices that use the physical expansion and contraction of materials (like non-compressable fluids,
vapors, or differential metals) to mechanically open or close a set of contacts.

  • Examples of mechanical temperature sensors are bulb and capillary thermostats, thermometers, mechanical temperature switches, and bi-metallic thermostats.
Electrical temperature sensors:

These sensors undergo a measurable electrical change such as resistance, voltage, or current proportional to a given change in temperature.
Temperature Probe Assembly
Temperature Probe Assembly

  • Examples are thermocouples which generate a micro-voltage based upon a temperature differential between two dissimilar metals; RTDs that increase resistance as the sensing temperature increases; and thermistors,  which dramatically decrease resistance as temperature increases. 
Electrical temperature sensors can be housed in a wide variety of sheaths and/or wells for protection, and come in varying tolerances and accuracies to best suit their intended use.

For more information on temperature sensors, contact Power Specialties at (816) 353-6550 or visit http://www.powerspecialties.com.