As a temperature sensor, thermocouple assembly is usually used with display instruments, recording instruments and signal conditioners.
Specification:
1. Thermocouple temperature range chart
Category | Type of sensing element | Relationship between wire diameter and temperature |
Thermo wire diameter (mm) | Long-term temperature (℃) | Short-tem temperature (℃) |
Platinum Rhodium 30 - Platinum Rhodium 6 | B type | Φ0.5 | 1600 | 1800 |
Platinum Rhodium 13 - Platinum | R type | Φ0.5 | 1300 | 1600 |
Platinum Rhodium 10 - Platinum | S type | Φ0.5 | 1300 | 1600 |
Nickel chromium silicon - Nickel silicon magnesium | N type | Φ0.3 | 700 | 800 |
Φ0.5 | 800 | 900 |
Φ0.8, Φ1.0 | 900 | 1000 |
Φ1.2, Φ1.6 | 1000 | 1100 |
Φ2.0, Φ2.5 | 1100 | 1200 |
Φ3.2 | 1200 | 1300 |
Nickel chromium - Nickel silicon | K type | Φ0.3 | 700 | 800 |
Φ0.5 | 800 | 900 |
Φ0.8, Φ1.0 | 900 | 1000 |
Φ1.2, Φ1.6 | 1000 | 1100 |
Φ2.0, Φ2.5 | 1100 | 1200 |
Φ3.2 | 1200 | 1300 |
Nickel chromium - Copper nickel | E type | Φ0.3 | 350 | 450 |
Φ0.5 | 450 | 550 |
Φ0.8, Φ1.0 | 550 | 650 |
Φ1.2, Φ1.6 | 650 | 750 |
Φ2.0, Φ2.5 | 750 | 900 |
Iron - Constantan | J type | Φ0.3, Φ0.5 | 300 | 400 |
Φ0.8, Φ1.0 | 400 | 500 |
Φ1.2, Φ1.6 | 500 | 600 |
Φ2.0, Φ2.5 | 600 | 750 |
Copper - Copper nickel | T type | Φ0.2 | 150 | 200 |
Φ0.3, Φ0.5 | 200 | 250 |
Φ1.0 | 250 | 300 |
Φ1.6 | 350 | 400 |
2. Thermowell application temperature range chart
Thermowell material | Long-term temperature | Short-term temperature |
Corundum CT1 | 1600 | 1800 |
High alumina CT2 | 1300 | 1600 |
Nickel base wrought superalloys 3YC52 | 1300 | 1350 |
Nickel base wrought superalloys GH3039 | 1250 | 1320 |
Nickel base superalloys GH3030 | 1200 | 1250 |
Heat resistant stainless steel 2Cr25Ni20 | 1200 | 1250 |
Silicon carbide | 1100 | 1150 |
Stainless steel 316L | 900 | 950 |
Stainless steel 1Cr18Ni9Ti | 800 | 900 |
3. Thermowell installing form (unit: mm)

4. Selection chart
Total length of thermowell (L or L*L1) | Branch number | Thermowell installing form | Protection head form | Diameter and material of thermowell |
300~2150mm (for I1, I2, I3, I4); 500*500mm, 750*500mm, 750*750mm (for I5); 225~450mm (for I6) | B1: Single branch; B2: Double branch | I0: No thermowell; I1: No fixed device; I2: Fixing thread; I3: Movable flange; I4: Fixed flange; I5: Rectangular movable flange; I6: Taper thermowell and fixing thread | C1: No protection head; C2: All stainless steel protection head; C3: Waterproof protection head; C4: Explosion-proof protection head | D0: Φ16mm; D1: Φ25mm, double-deck; D2: Φ16mm high quality aluminum; D3: Φ20mm high quality aluminum |
5. Thermocouple assembly installation diagram

Tips: Thermocouple assembly installation
- On the conduit, the temperature-sensing element should form countercurrent with the measured medium, at least 90 degree angle to the medium measured.
- No matter measuring the temperature of any medium, the temperature-sensing element should be placed in the point that needs to be measured. If it is in conduit, the temperature-sensing element should be placed at the point of highest flow velocity. That is, the welding points of thermocouple temperature-sensing element should be placed at the maximum flow velocity.
- There should be enough insertion length. The experiment shows that the measurement error of thermocouple is reduced with the increase of the insertion length. If condition permits, the insertion length should be increased as far as possible to ensure the accuracy of the measurement.
- The protection head should be placed upwards and the outlet bolts of the protection head should be placed downwards during installation, in order to prevent liquid immersed in thermocouple protection head. Don't let the protection head of thermocouples place in a position of high temperature and harmful atmosphere. If it is unavoidable, rectangular structure thermocouple can be used.
R type thermocouple assembles with protection head and corundum thermowell, should use wooden case for packing. Its thermo wire diameter is Ф0.5mm. R type thermocouple can directly measure the temperature in the range of 0~1600 ℃ in various production processes.