Thermocouple
THERMOCOUPLE
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.
Thermocouple Type & Temperature Range
| TC Type | Name of Materials | Application Range |
| B | Platinum 30% Rhodium (+) | 1200-1800°C |
| Platinum 6% Rhodium (-) | ||
| C | W5Re Tungsten 5% Rhenium (+) | 1650 – 2315°C |
| W26 Re Tungsten 26% Rhenium (-) | ||
| E | Chromel (+) | 0-900°C |
| Constantan (-) | ||
| J | Iron (+) | 0-760°C |
| Constantan (-) | ||
| K | Chromel (+) | 0-1200 °C |
| Alumel (-) | ||
| N | Nicrosil (+) | 650-1260°C |
| Nisil (-) | ||
| R | Platinum 13% Rhodium (+) | 870-1650°C |
| Platinum (-) | ||
| S | Platinum 10% Rhodium (+) | 980-1650°C |
| Platinum (-) | ||
| T | Copper (+) | -200°C – 350°C |
| Copper (+) |
PROTECTION SHEATHS
Seamless Tube And drilled bar stock
| 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. | ||
| 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. |