A thermocouple is a device that is used in measuring temperature. It consists of two dissimilar metallic wires that have been connected together in order to form a junction. In situations or conditions when the junction is cooled or heated, a small voltage that is measurable is produced in the electrical circuit of the thermocouple, which correlates to temperature.
Although in theory, it is possible to make any two metals a thermocouple, but practically, there are a limited number of types that are generally used. They’ve been created to provide improved accuracy and linearity, and mostly consist of specially made alloys.
Thermocouples can be developed in order to befit just about any kind of c c application. They can be developed to provide sturdy, quick response, along with the ability to measure a wide range of temperatures.
Working of a Temperature thermocouple
In 1821, the resulting discovery of the Seebeck effect, by Thomas J. Seebeck led to the development of Thermocouples. Inside an electrical circuit, two dissimilar metals are connected together at both ends. One of these “junctions” is called the reference junction or “cold end”. The other is referred to as the measuring junction or “hot end”. Then, a sensitive voltmeter is then linked to one of its conductors.
When subjected to laboratory conditions, the reference junction is usually kept at 0°C but in normal industrial practice conditions, the junction is kept at ambient temperature by utilizing an external sensor in order to compensate for this variation. This kind of compensation is known as cold junction compensation.
To put it in a simple way, as the temperature either increases or decreases at the measuring junction a voltage is created inside the circuit that is in direct correlation with the temperature, which could be converted easily by referring to the appropriate tables.
Explain a thermocouple probe
Now that we have an understanding of what a thermocouple actually is, and how it works under different temperatures. Lets understand another popular question that comes up, which is, what is a thermocouple probe?
A thermocouple probe basically refers to the design that is used to create the sensor. It doesn’t matter if the sensor may be a thermocouple type K, J, T, N; it is possible to manufacture any of these thermocouple types using the same size tube, construction or housing.
Thermocouples tend to look different depending on the ‘housing’ that is used to manufacture it. Although a thermocouple by itself consists of only two bare wires that have been connected together, it is possible to put these two wires inside a variety of housings so that they are protected and eventually they last longer.
What do you mean by a type K thermocouple?
A type K Thermocouple is created by using two dissimilar metals namely Nickel-Alumel / Nickel-Chromium. Type K is the one of the most used types of thermocouple because it is dependable (depending on the design that your application utilizes), precise, costs less, and also covers a wide range of temperatures.
Type K thermocouples could be useful in a wide range of applications because of its extensive temperature range capabilities. The maximum continuous temperature could go up to almost 1100°C.
Thermocouples with a cable or plug may be identified by referring to their color coding. The color of type K is green. In this case, the white leg of the cable is negative, and the green leg is positive.
What do you mean by a J thermocouple?
Type J Thermocouples are also very widely used. When compared to a type K thermocouple, they have a smaller temperature range, ranging between 0 to 600°C. The Type J is created using two dissimilar metals namely Copper-Nickel / Iron. When it comes to cost, they are very similar to type K.
Their use in the plastics industry is one of the most well-known applications of type J thermocouples.
Thermocouples that have a cable or plug may be identified by simply looking at their color coding. In this scenario the color of type J is Black. In this type of cable, then you can treat the white leg as negative and the black leg as positive.
Heatcon Sensors is an ISO 9001:2015 certified company that has been operational for 30 years. Heatcon has received accreditation from several certifying bodies such as TUV SUD, DRDO CEMILAC, NSIC, and NABL. Making heat sensing devices like Thermocouples and RTDs has been our forte! We also produce special sensors that are used in numerous industries including the ones specializing in aeronautics, railways, turbines, nuclear plants, and research labs.
With over three decades of expertise in temperature sensor and heater manufacturing, Heatcon Sensors provides a high level of quality, accuracy, and an unbeatable commitment to customer support.
If you are interested in knowing more about thermocouples, thermocouple probes or thermocouple wires that we manufacture, and also of the other services we offer, please feel free to call us on (+91-9844233244).