Transducer

Thermocouple

The thermocouple remains as the most extensively used element in temperature measurement!

How does a it work?

Made of two different metals welded together at one end. It generates electromotive force (emf) as a result of the difference in temperature between its cold and hot points of connection. This is in essence, the thermocouple theory behind it all.


It is also referred to as thermoelectric effect or Seebeck effect. It was first discovered by Thomas Johann Seebeck in 1821. Another scientist, Jean Charles Athanase Peltier noted that each junction in the thermoelectric circuit is a source of potential difference also known as Peltier effect.

Sir William Thomson or Lord Kelvin added his own insight to the work of Seebeck and Peltier, this is known as the Thomson effect. Overall these three scientists are pioneers in the development of thermoelectricity, the basis for the above subject.

Besides temperature difference, wire-metal properties affect the resultant emf. Of the metals commonly used to make these thermoelectric devices are a combination of base or noble metals. They measure temperatures from close to absolute zero to about +1760 °C. There are also special metal alloys that are at hand for temperatures up to +3093 °C.

A wide variety of these devices are present and ready for use depending on their sensitivity and range of temperature measuring applications. Of the types available are calibrations J,K,E,N,B,R and S,T,C,M and Chromel-gold/iron.

K Type output transducer consisting of a positive Chromel wire and a negative Alumel wire is the most popular. A wide measurement range and reasonable sensitivity make it the most practical to use.

J Type thermo-couple is made up of iron and Constantan. Iron being the positive wire and Constantan the negative wire. It is considered less in demand than type K because of its narrow temperature measuring range at -40 to +750 °C.



Plus the fact that it can be sensitive to corrosion because of its iron element. However, it is inexpensive and readily available.

Type T is composed of copper wire which is the positive element and Constantan the negative element. It is usually used within the temperature range of -200 to 350 °C. Common uses include below zero temperature measurements and monitoring applications.

These three are the most common types. Although others can be sourced out depending on the nature or environment in which they are intended to be used.

Transducer manufacturers have a ready configuration table or thermo-couple color code guide for every possible application in their catalogs, and technical support of expert engineers should there be a need.

Thermocouple Transducer Systems

Thermo-couple Transducer Systems compose of interrelated components involving the use of thermocouples, measuring, monitoring and recording devices.

Following below are some of the available thermoelectric transducer systems.

1) Taylor Professional 9306 Dual Temp IR/Thermocouple Thermometer

thermocouple transducer
Taylor Professional 9306 Dual Temp IR/Thermocouple Thermometer

  • 3-Inch dial measures temperatures from 120 to 200-degrees fahrenheit
  • Face displays proper meat, poultry, and yeast temperatures
  • Made of stainless steel with 3-1/2-inch stem
  • Easy to read ; needs no skewer
  • Safe to use in dishwasher

2) Cole-Parmer Workhorse Thermo-couple Thermometer Type-K

thermocouple transducer
Cole-Parmer Workhorse Thermocouple Thermometer Type-K
  • Easy to use meter at an economical price that is perfect for everyday use
  • Temp range: -58 to 2372°F (-50 to 1300°C)
  • Type: Thermo-couple Type K
  • Resolution: 0.1° between -50.0 to 200°C and 1° otherwise
  • Accuracy: ±1°C +.75 between 500 to 750°C, ±1°C + 2% between 750 to 1000 °C, ±3°C + 4% between 1000 t

3) Dual Digital Display PID Temperature Controller. Ideal for FURNACE and KILN control

thermocouple transducer
Dual Digital Display PID Temperature Controller. Ideal for FURNACE and KILN control
  • 3 mode of Auto-Turning with PID Algorithms
  • Dual Display for Setpoint and Present
  • Support both Fahrenheit (F) and Celsius(C)
  • Lower power consumption (less than 3Watt)
  • Support SSR or Relay alarm output


4) Cole-Parmer Remote-Monitoring Thermo-couple Thermometer (Deg. F)

thermocouple transducer
Cole-Parmer Remote-Monitoring Thermo-couple Thermometer (Deg. F)
  • For use in remote measurement applications
  • Temp range: -58 to 1382°F
  • Accuracy: ±2°F .75% between 32 to 932°F and ±2°F 1% between 933 to 1382°F
  • Power: 9-Volt Alkaline battery (included)
  • Probe: Thermo-couple


Related Articles




Omega thermo-couple - Opting for branded thermocouples like Omega for your industrial or even personal requirement is always a safe bet.

However, simply buying a branded Omega thermocouple will not help you if you do not consider important factors when finalizing the purchase.

Take a look at some factors that must be given due importance before opening your purse strings.

Furnace thermo-couple, as the name suggests, is used to determine the temperature inside a furnace. This device offers many safety and functional benefits.

IR thermo-couple is also known as a contact less thermo-couple.

As the name suggests, an infrared thermo-couple enables us to analyze and assess the temperature of any object without bringing the thermometer or the device in contact with the thing or object under consideration.

Thermo-couple Power The function of a thermo-couple is to measure temperature by measuring the electrical charge generated by temperature difference between two metals.

Further, the thermocouple can be configured to utilize the electricity generated to power other devices.

The function of a thermo-couple does not stop at measurement alone. It also includes utilization of the same.

Thermo-couple adapters permit the coupling of a thermocouple with small and flat pins or large and round pins to fit into controllers.

The use of thermo-couple amplifier is to boost the signal from the thermocouple so that the signal can be measured using various measuring devices.

An electric water heater thermo-couple will measure the temperature of the water and disconnect the power supply when it reaches the right water temperature.

It is important to use thermo-couple tester to determine whether the thermoelements are working properly prior to installation.

The different types of thermo-couple wiring are distinguished with the help of color coding and charts. Needless to say, it is very important to use the right wiring for the right junction and the right purpose.

Thermocouple circuit involves the generation of voltage in a loop of two unrelated metals as a result of temperature difference between its two junctions.





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