Properties of Type B Thermocouples
The B type thermocouple range makes it ideal for extremely high temperature applications. This thermocouple remains stable and accurate up to 1800°C. Specialty of thermocouple B is that it has the highest temperature limit of all thermocouple types. These thermocouples produce the same output at 0°C and 42°C, limiting their use below about 50°C. The emf function has a minimum around 21°C, making cold-junction compensation easier.
Advantages and Disadvantages of Type B Thermocouples
Vorteile
- Provides highest accuracy in comparison to other thermocouples
- Measures at a wide temperature range: Continuous: 200 – 1800°C, Short: 0 – 1850°C
- Sehr schnelle Reaktion bei höheren Temperaturen (über 500 °C)
Disadvantages
- Provides least output emf per degree Celsius change in temperature
- Teurer als andere Typen, da Platinlegierungen verwendet werden
- Slower response for measurements below 500°C
- Kann nicht für Minustemperaturmessungen verwendet werden
- Lower output than type R & S below 600°C (1112°F)
Why Choose Type B Thermocouple?
Composition
Type B Thermocouple consists of a positive leg (70% Platinum, 30% Rhodium) and a negative leg (94% Platinum, 6% Rhodium). With compacted mineral insulation and appropriate sheathing, it operates from 600 to 1704°C (1100 to 3100°F).
Temperaturbereich
- With mineral insulation and proper sheath: 600°C to 1700°C (1100°F to 3100°F)
- Thermocouple grade wire: 0 to 1700°C (32 to 3100°F)
- Extension wire: 0 to 100°C (32 to 212°F)
Genauigkeit (je nachdem, was größer ist)
- Standard: ±5%
- Special Limits of Error: ±0.25%
Type B Insulation Material
Ceramic beads: Made from high-purity alumina-silicate, with low thermal mass and conductivity, withstands up to 1260°C.
Magnesium Oxide (MgO): Suitable for liquids, moisture, corrosive gases, and high-pressure environments. Durable and fast-responding.
Type B Thermocouple Reference Table
For quick temperature conversions visit the Type B Thermocouple Reference Table.
EMF VS Temperature Graph
Abschluss
The B type thermocouple is the industry’s benchmark for continuous high-temperature monitoring. Its platinum-rhodium construction and high operational range provide reliable and accurate readings in extreme environments. Though it’s costlier and unsuitable for low-temperature use, its benefits outweigh limitations in harsh applications.
FAQs
Do Type B thermocouples require calibration?
Yes. Periodic calibration is recommended, especially in critical processes and after long-term high-temperature use.
What color code is used for Type B thermocouples?
Grey for the positive leg and red for the negative leg.
Is Type B thermocouple suitable for vacuum applications?
Yes, when properly insulated and sheathed, it works well in vacuum, inert, and oxidizing atmospheres.
Can Type B thermocouples be reused?
Yes, if inspected and tested for integrity. However, repeated use at high temperatures may degrade performance.
