How to Choose the Right Thermocouple

Choosing the thermocouple should be based on the temperature range, the required accuracy, used atmosphere, the performance of the measured object, response time, the economic benefits and so on. Then to take comprehensive consideration.

1. The factor of accuracy and temperature measurement range

When the usage temperature is 1300 ~ 1800℃,generally B type thermocouple is selected if the required accuracy is high; Tungsten Rhenium thermocouple is also available if the required accuracy is not high, and the atmosphere is allowed. When temperature is higher than 1800℃, generally Tungsten Rhenium thermocouple is selected. When temperature range is at 1000 ~ 1300℃ and the required accuracy is higher, S type thermocouple and N type thermocouple are options; K type thermocouple and N type thermocouple are available for temeprature below 1000℃; Below 400℃ generally using E type thermocouple; under 250℃ and Negative temperature measurement, T thermocouple is used, T thermocouple has stability and high precision during low temperature.

2. The factor of used atmosphere

S type, B type, K type thermocouples are suitable for strong oxidation and weak reducing atmosphere, J type and T type thermocouple are suitable for weak oxidizing and reducing atmosphere. If using protection tube with better air tightness, the requirement for atmosphere is not too strict.

3. The factor of durability and thermal response

If the wire diameter of thermocouple is large, its durability is good, but the response is slow. For the big heat capacity of thermocouple, the response is slow, temperature control ability is poor with wide temperature range. If fast response time and high durability is required, armored thermocouple is appropriate.

4. The factor ofthe nature and state of the measured object

The temperature measurement for the moving objects, vibrating objects and high pressure vessels requires high mechanical strength. The atmosphere with chemical pollution requires a protective tube, high insulation is required under the condition of the electrical interference.

Selection process: case type—graduation --explosion-proof grade--precision grade--installation & fix types--protection tube material -- length or insert depth.

Product selection and ordering information:

1) When selecting the right sensor and ordering, please specify: case type (part number), graduation, probe material and diameter, probe length and insert depth I, fixing installation type, temperature measurement range.

2) Any special requirement or customized temperature sensor needed, please contact us freely for further solution.