A thermocouple is a widely used temperature sensor, mainly due to its robustness, simplicity, and affordability. It connects two different metals at their ends, forming a closed circuit. When there is a temperature difference between the junctions, this structure generates an electromotive force. As a result, the thermocouple measures temperatures over a wide thermal range. Therefore, it is essential in various industrial and laboratory processes.
How does a thermocouple work?
The operating principle of the thermocouple is based on the Seebeck effectThis phenomenon explains why, when there is a temperature difference between two points in a closed circuit, an electrical voltage is generated that is proportional to the thermal variation. With this voltage, it is possible to determine the temperature using calibration tables specific to each type of thermocouple.
Furthermore, the measurement process is straightforward and reliable, as long as the model is compatible with the application.
Types of thermocouples and their applications
Os thermocouples They are offered in different calibrations and are given classification letters according to the metals used. Therefore, to ensure efficient performance, it is essential to consider both the application and the required temperature range.
Main types of thermocouples:
| Type | Positive Element | Negative Element | Usual Temperature Range | Standard Error Line (Choose Largest) | Special Error Line (Choose Largest) |
|---|---|---|---|---|---|
| T | Copper | Constantine | -200 0 ° C ° C ~ | +/-1°C or +/-1,5% | - / - |
| T | Copper | Constantine | 0 ° C ~ 370 ° C | +/-1°C or +/-0,75% | +/-0,5°C or +/-0,4% |
| J | Iron | Constantine | 0 ° C ~ 760 ° C | +/-2,2°C or +/-0,75% | +/-1,1°C or +/-0,4% |
| E | Cromel | Constantine | 0 ° C ~ 870 ° C | +/-1,7°C or +/- 0,5% | +/-1,0°C or +/-0,4% |
| K | Cromel | Alumel | 0 ° C ~ 1260 ° C | +/-2,2°C or +/- 0,75% | +/-1,1°C or +/-0,4% |
| N | Nicrosil | Nisil | 0 ° C ~ 1260 ° C | +/-2,2°C or +/- 0,75% | +/-1,1°C or +/-0,4% |
| S | 90% Platinum / 10% Rhodium | Pt 100% | 0 ° C ~ 1480 ° C | +-1,5°C or +/- 0,25% | +/-0,6°C or +/-0,1% |
| R | 87% Platinum / 13% Rhodium | Pt 100% | 0 ° C ~ 1480 ° C | +/- 1,5°C or +/- 0,25% | +/-0,6°C or +/-0,1% |
| B | 70% Platinum / 30% Rhodium | 94% Platinum / 06% Rhodium | 870 ° C ~ 1700 ° C | + / - 0,5% | +/- 0,25% |
How to choose the ideal thermocouple?
Each model has its own characteristics. While some can withstand extremely high temperatures, others stand out for their precision in lower temperature ranges. Therefore, it's essential to carefully analyze the application before making a decision.
In addition to temperature, also consider factors such as:
- Environmental conditions (humidity, corrosion, pressure)
- Required response time
- Compatibility with measuring instruments
By evaluating all these criteria, you ensure more reliable and lasting results for your process.
Applications and advantages of thermocouples
Thermocouples remain one of the most versatile temperature measurement solutions. They are used in industries, laboratories, production lines, and even research centers. When properly specified, they increase operational safety and optimize overall system performance.
Another strong point is their cost-effectiveness. As a result, thermocouples are ideal for large-scale applications, especially in continuous production environments.
Alutal offers the ideal solution
Alutal provides a full line of thermocouples and temperature sensorsWe develop our products with a focus on quality, durability, and precision, meeting the most diverse needs of national and international industries.
Contact us and discover the best temperature sensor solution for your application!
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