Comparison between S-type thermocouple and K-type thermocouple

S-type thermocouples and K-type thermocouples are rare sensors used to measure temperature in the thermocouple series. However, in practical manipulation situations, there are still differences between S-type thermocouples and K-type thermocouples.

Advantages of S-type thermocouple:

1. High measurement accuracy, S-type thermocouple has the highest measurement accuracy among all thermocouples;

2. Stable physical and chemical functions with good reproducibility;

3. Good antioxidant function at low temperatures;

Problems with S-type thermocouples:

1. Belonging to precious metal thermocouples, it has a high cost and is only slightly cheaper than B-type thermocouples in all thermocouple series;

2. The machine has poor strength and low thermoelectric potential, especially at high temperature ends where thermocouples are small and require measuring instruments with high sensitivity;

3. The diameter of the thermocouple wire (0.35mm-0.5mm) is very thin, and the machine strength is poor;

Advantages of K-type thermocouple:

1. Low temperature cheap metal thermocouples, with a low price and widespread application, account for about half of the total annual production of metal thermocouples;

2. Good reproducibility, the correlation between thermoelectric potential and temperature is approximately linear;

3. High thermoelectric potential: 52.4mV/1300 ℃, high thermoelectric potential rate: 41UV/℃;

4. Good antioxidant function, can be temporarily applied in oxidative atmospheres and environments;

Problems with K-type thermocouples:

1. The stability is slightly poor. Within the temperature range of 150-200 ℃, magnetic changes are easily generated. Within the temperature range of 250-550 ℃, the thermoelectric potential will show irregular changes in heating sequence (due to hysteresis). If temporarily applied at low temperatures, the thermoelectric motor may not be stable;

2. Not suitable for application in vacuum, carbon containing, and sulfur-containing atmospheres.