Description
Non-Metal Thermocouple Tubewells
| Material | Chemical Symbol |
Operating Temperature |
Remarks |
| Sintered Alpha |
SASiC | 3000°F (1650°C) |
No free silicon, higher density than SiC, low porosity, excellent Silicon Carbide thermal shock resistance, high chemical, corrosion and abrasion resistance. Excellent thermal conductivity. |
| Silicon Carbide |
SiC | 3000°F (1650°C) |
Excellent thermal conductivity, corrosion resistance and abrasion resistance, good thermal shock resistance. |
| Fused Quartz |
SiO2 | 3050°F (1677°C) |
Excellent thermal shock resistance, unreactive to most acids and metals, performs well in oxidizing, inert or neutral atmospheres. |
| Mullites | 3Al2O32SiO2 | 2750°F (1510°C) |
Low thermal expansion, good thermal shock resistance, excellent mechanical strength. |
Tolerance of Thermocouples
| °C | °F | ||||||
| ANSI/ASTM | Temperature Range | Standard | Special | Temperature Range | Standard | Special | |
| R or S | 0° to 600° 600° to 1480° |
±1.5° ±0.25% T |
±0.6° ±0.1% T |
32° to 1112° 1112° to 2700° |
±2.7° ±0.25% (T-32) |
±1.08° ±0.1% (T-32) |
|
| B | 870° to 1700° | ±0.5% T | ±0.25% T | 1600° to 3100° | ±0.5% (T-32) | ±0.25% (T-32) | |
| C♠ | 0° to 426° 426° to 2315° |
±4.4° ±1% T |
– | – 32° to 800° – 800° to 4200° |
±8° ±1% (T-32) |
– | |
♠ Formerly Conax Technologies Type W5, Type C not an ANSI official designation.
Thermocouple Characteristics
| ANSI/ASTM | Symbol Single |
Generic Names |
Color Coding Individual Conductor |
Color Coding Overall Jacket Extension Grade Wire |
| S | SP SN |
Platinum 10% Rhodium Platinum |
Black Red |
Green |
| R | RP RN |
Platinum 10% Rhodium Platinum |
Black Red |
Green |
| B | BP BN |
Platinum 30% Rhodium Platinum 6% Rhodium |
Gray Red |
Gray |
| C | CP CN |
Tungsten 5% Rhenium Tungsten 26% Rhenium |
Green Red |
Red |
