Type K Thermocouple

1. Principle: Based on Seebeck effect, two different metal conductors A and B form a closed loop, and the thermoelectric motive force will be generated when the temperature at both ends is different, so as to calculate the measured temperature.

Structure: It is generally composed of thermal electrode (nickel-chromium-nickel-silicon), insulating sleeve, protective tube and junction box. The measuring end of the thermal electrode is welded to feel the temperature, the insulating sleeve is anti-short circuit, the protective tube is anti-erosion and mechanical damage, and the junction box is used to connect the instrument.

3. Features: Temperature measurement range -200 ℃ to 1300℃, high accuracy, error can be controlled within ±2.2℃ or ±0.75% (take the larger value), good stability, anti-oxidation, fast response, cost-effective.

4. Application: Used for equipment temperature measurement in petrochemical, steel, electric power and other industrial fields; Accurate temperature measurement in scientific experiments; Measuring engine temperature in automobile; Daily household appliances, such as ovens, water heaters, etc. are used for temperature detection and control. 

Type K Thermocouple Specifications：

1. Thermal electrode diameter: generally 1.2mm-4.0mm.

2. Index number: K.

3. Measuring range: normal operating temperature is -200 ℃-1300℃.

4. Accuracy level: Generally divided into I and II levels. Class I precision is relatively high, the error range is small; Class II accuracy is slightly lower. There are also accuracy grades according to ±0.5℃, ±1.0℃, ±2.5℃, ±5.0℃, etc.

5. The basic error limit: usually ±0.75% t (t is the measured temperature value of the temperature sensing element).

6. Time constant: thermal inertia level I is 90-180 seconds; The second is 30-90 seconds; Iii is 10-30 seconds; Ⅳ Less than 10 seconds.

7. Nominal pressure: refers to the static external pressure that the protection tube can withstand at the operating temperature without breaking.

8. Minimum insertion depth: it should not be less than 8-10 times the outer diameter of its protective casing (except for special products).

9. Insulation resistance: ambient air temperature is 15-35℃, relative humidity < 80% insulation resistance ≥5 megohm (voltage 100V); Thermocouple with splash-proof junction box, insulation resistance ≥0.5 megohm (voltage 100V) at a relative temperature of 93±3℃.

10. Insulation resistance at high temperature: when the long-term use temperature is ≥600℃, the test temperature is 600℃, and the insulation resistance value is ≥72000Ω; ≥800℃, test temperature 800℃, insulation resistance value ≥ 25,000ω; ≥1000℃, test temperature 1000℃, insulation resistance value ≥5000Ω.

11. Dimensions: Common Φ3×300mm, Φ3×500mm, Φ3×1000mm, Φ3×1500mm, Φ4×300mm and other size combinations.

12. Installation fixed form: fixed thread type, movable flange, fixed flange type, movable flange square form, fixed thread conical protection tube type, etc.

13. Junction box form: splash-proof, waterproof, flameproof, etc

The Advantages and Disadvantages of Type K Thermocouples

1. Wide temperature range: can measure -200 ℃ to 1300℃, after special treatment, the range is wider, suitable for a variety of high temperature and low temperature scenarios.

2. High accuracy: the error is usually within ±2.2 ° C or ±0.75% (take the larger value), which can provide reliable temperature data for most scenarios.

3. Good stability: chemical stability, strong oxidation resistance, stable thermoelectric characteristics, anti-interference, long life.

4. Fast response speed: the thermal electrode has a small heat capacity and can quickly sense temperature changes, which is suitable for scenarios with frequent temperature fluctuations.

5. High cost performance: simple process, reasonable cost, to meet the common temperature measurement needs at the same time the price is close to the people, widely used.