Thermocouple EGT Sensor

How does the Thermocouple EGT Sensor work?

1. The Seebeck Effect Generates Thermoelectric Potential
A thermocouple consists of two dissimilar metal wires connected at the measuring junction. When a temperature difference occurs between the measuring junction and the reference junction, an electromotive force (thermoelectric potential) proportional to the temperature difference is generated. This voltage signal is the source of temperature information.

2. Conversion of Thermoelectric Potential to Temperature
Using a known thermoelectric potential-temperature correspondence table (or standard function), the instrument converts microvolt-level voltages into corresponding temperatures, enabling continuous measurement. This process requires no external power, making it a self-powered sensor.

3. Cold Junction Compensation Ensures Accurate Measurements
The reference junction (cold junction) is typically maintained at a known temperature (such as room temperature). Cold junction compensation is performed internally in the instrument to eliminate the effects of cold junction temperature variations on measurement results.

4. Structural Design Enhances High-Temperature Reliability
Sook High Tech's Thermocouple EGT Sensor utilizes a mineral-insulated alloy sheath and a specialized sealing ring. This ensures structural stability in extreme environments ranging from -40°C to 1000°C, resisting mechanical vibration, particle erosion, and chemical corrosion, extending its service life. What are the differences between a Thermocouple EGT Sensor and other temperature sensors (RTDs, Thermocouples)?
1. Temperature Measurement Range

Thermocouples (including Thermocouple EGT Sensors) cover a wide temperature range of -200°C to 2300°C, making them suitable for extreme applications such as high-temperature gases and gas turbines.
RTDs (Platinum Resistance Detectors) typically measure temperatures between -200°C and 850°C, offering high accuracy but unsuitable for extremely high temperatures.
Thermocouples (NTCs/PTCs) have a narrower temperature range and are typically used for low to medium temperature measurements.
2. Signal Type and Accuracy

Thermocouples output millivolt-level voltages, which have relatively low accuracy and require amplification and cold-junction compensation.
RTDs output a resistance change signal with good linearity and high accuracy, making them suitable for applications requiring stringent accuracy.
Thermocouples output a resistance change signal with high sensitivity but nonlinearity, making them suitable for cost-sensitive applications with low accuracy requirements. 3. Response Speed ​​and Durability

Thermocouples offer a simple structure, lightweight weight, low thermal inertia, and fast response. Sook High Tech's "small probe + armored structure" further reduces thermal inertia, enabling rapid detection of temperature fluctuations.

RTDs, due to their large metal resistor body and high thermal mass, respond relatively slowly.

Thermocouples have a response speed somewhere in between due to their material properties, but are susceptible to damage in high-temperature and high-vibration environments.

4. Cost and Installation

Thermocouples offer the lowest cost and enable long-distance signal transmission, making them suitable for high-volume industrial deployment.

RTDs are more expensive and require three- or four-wire compensation wiring, making installation more complex.

Thermocouples offer the lowest cost, but their lifespan is limited in high-temperature or corrosive environments.