The principle on which the modern thermocouple operates is derived from Seeback’s discovery that if a circuit is formed using two dissimilar metal Conductors with one junction at a higher temperature than other, then a current will flow in the circuit. The resultant emf. is proportional to the temperature difference between the junctions .
For many industries heating processes particularly those carried out at high temperature a Thermocouple is the most accurate convenient and simple method for temperature measurement.
TC Type |
Name of Materials |
Application Range |
B |
Platinum 30% Rhodium (+) |
1200-1800°C |
Platinum 6% Rhodium (-) |
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C |
W5Re Tungsten 5% Rhenium (+) |
1650 – 2315°C |
W26 Re Tungsten 26% Rhenium (-) |
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E |
Chromel (+) |
0-900°C |
Constantan (-) |
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J |
Iron (+) |
0-760°C |
Constantan (-) |
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K |
Chromel (+) |
0-1200 °C |
Alumel (-) |
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N |
Nicrosil (+) |
650-1260°C |
Nisil (-) |
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R |
Platinum 13% Rhodium (+) |
870-1650°C |
Platinum (-) |
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S |
Platinum 10% Rhodium (+) |
980-1650°C |
Platinum (-) |
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T |
Copper (+) |
-200°C - 350°C |
Copper (+) |
Type |
Max. Temp (Recommended) |
Remarks |
SS304 |
870°C |
Most widely used low temperature sheath material. |
Extensively used in food, beverage, chemical and other industries where corrosion resistance is required. |
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SS316 |
870°C |
Best corrosion resistance of the austenitic stainless steel grades. Widel used in the food and chemical industry |
SS310 |
1150°C |
Mechanical and corrosion resistance,similar to but better than 304 S S .Very good heat resistance |
446 SS |
1150°C |
Ferritic stainless steel which has good resistance to sulfurous atmospheres at high temperatures. corrosion resistance to nitric acid, sulfuric acid and most alkalies. |
INCONEL 600/601 |
1175°C |
Good high temperature strength, corrosion resistance, resistance to chloride-ion stress corrosion cracking and oxidation resistance to high temperatures. |
Metal Ceramic |
1370°C |
Used in Copper, Brass and Steel industry |
Silicon Carbide |
1650°C |
Used in Aluminium Industry |
Syalon® |
1150°C |
Used in aluminium Industry |
Ceramic 610 |
1600°C |
Excellent thermal mechanical and corrosion resistance. |
Ceramic 710 |
1800°C |
Excellent thermal mechanical and corrosion resistance. |