What is an N-type thermocouple?

An N-type thermocouple is a type of temperature sensor that belongs to the thermocouple family. It is a device that uses the Seebeck phenomenon, which involves the generation of an electrical voltage in a circuit composed of two different metals (or alloys) when their connections are subjected to different temperatures. The N-type thermocouple consists of two specific materials: a nickel-chromium-silicon alloy (Nicrosil) and a nickel-silicon alloy (Nisil).

Characteristics of N-type thermocouples

These temperature sensors are used for the precise measurement of temperatures over a wide measuring range, reaching from about -270°C to about 1300°C. The alloys from which they are made provide them with exceptional thermoelectric properties and high resistance to corrosion and oxidation. These features make N-type thermoelectric sensors suitable for applications in harsh industrial environments, such as metallurgy and the chemical industry.

The use of type N thermocouples

Type N thermocouples are particularly valued in applications requiring precise and reliable temperature measurements in difficult conditions. Here are the five most important applications:

1. Metallurgical Industry: They are crucial for monitoring temperature in furnaces and metal processing, where high resistance to high temperatures is required.
2. Heat Treatment Industry: Essential in the processes of hardening and tempering of metals, where precise temperature control is key to the quality of the final product.
3. Chemical Industry: Due to their corrosion resistance, they are indispensable in monitoring chemical processes, especially those occurring at high temperatures.
4. Scientific Research and Laboratories: Used for precise temperature measurements in scientific research, where stability and accuracy are key.
5. Power Industry: Used to monitor temperature at critical points in power plants, especially in high-temperature technologies.

Advantages and Disadvantages of Type N Thermoelectric Sensors:

Advantages of Type N Thermocouples:

• High Stability and Accuracy of Measurements: These thermocouples are known for their exceptional stability and accuracy across a wide range of temperatures.
• Resistance to High Temperatures: They can operate effectively at very high temperatures, making them an ideal choice for industrial processes such as metallurgy and heat treatment.
• Resistance to Corrosion and Oxidation: Thanks to the use of special nickel alloys, type N thermocouples are resistant to corrosion and oxidation, which increases their lifespan in harsh conditions.
• Versatility of Applications: They are versatile and can be used in a variety of industries, from heavy industry to scientific research.
• Longevity: They have a longer lifespan compared to some other types of thermocouples, which reduces costs associated with replacement and maintenance.

Disadvantages of Type N Thermocouples:

• Higher Cost Compared to Some Other Types of Thermocouples: Type N thermocouples can be more expensive to purchase than some other types, such as K or J, due to the use of specialized materials.
• Limitations at Extremely Low Temperatures: Although they are effective at high temperatures, their performance can be limited at very low temperatures.

Comparison of Type N Thermoelectric Sensors with Other Types of Thermocouples (Type K, J, T)

Compared to other commonly used thermocouples such as types K, J, and T, the type N thermocouple stands out for its better thermal stability and resistance to various forms of degradation, such as corrosion or oxidation. For example, compared to type K thermocouples, which are also used at high temperatures, type N thermocouples are more resistant to so-called "drift" when exposed to high temperatures for an extended period.

Temperature Range:

• Type N Thermocouples: From -270°C to 1300°C, ideal for measuring high temperatures.
• Type K Thermocouples: From -200°C to 1250°C, popular but less stable at very high temperatures.
• Types T and J Thermocouples: Limited to lower temperatures, up to 750°C and 350°C, respectively.
• Types B and S Thermocouples: Up to 1600°C, very accurate at high temperatures but relatively expensive.

Corrosion Resistance:

• Type N: Very good, especially at high temperatures.
• Type K: Good, but can be prone to corrosion in certain environments.
• Types J, T, S: Less resistant to oxidation and corrosion

Stability and Accuracy:

• Type N: High, ideal for difficult conditions.
• Type K: Good, but can experience drift at high temperatures.
• Type S: Very accurate but more expensive.

Cost:

• Type N: More expensive than K and J, but offers better performance in difficult conditions.
• Type K: More economical, a popular choice.
• Type S: The most expensive, used in precision applications.

These thermoelectric sensors are chosen for their high accuracy and stability in difficult conditions, while other types are better suited depending on application requirements such as temperature range, corrosion resistance, and cost.

About the author

My name is Ewelina Szmit and I have been working in the field of content marketing for several years, combining my professional skills with my passion for writing. I believe that even the most technical topics can be presented in a way that is interesting and accessible to everyone. Outside of work, I develop my creativity by making newspaper collages. I like to spend my free time most actively, walking my dog or running.