Micro thermocouple

　　Micro thermocoupleIt can directly measure the temperature of liquid, steam, gas media, and solid surfaces within the range of 0 ℃ to 600 ℃ in various production processes.Micro thermocoupleEspecially suitable for temperature measurement and control in narrow and curved places. It is a temperature measuring device used in industries such as chemical, synthetic fiber, and pharmaceuticals.

Technical Specifications

Accuracy level: Level I or Level II [Level 1 standard is ± 1.5 degrees below 375 °. Level 2 standard is ± 2.5 degrees]

Nominal diameter: Φ 1 Φ 0.5 Φ 0.35 [generally minimum outer diameter]

Basic Principles

Weld two different materials of conductors or semiconductors A and B together to form a closed circuit. When there is a temperature difference between the two attachment points 1 and 2 of conductors A and B, an electromotive force is generated between them, resulting in a current of a certain magnitude in the circuit. This phenomenon is called thermoelectric effect. Thermocouples work by utilizing this effect.

temperature compensation

Due to the fact that the materials of thermocouples are generally expensive (especially when using precious metals), and the distance between the temperature measuring point and the instrument is far, in order to save thermocouple materials and reduce costs, compensation wires are usually used to extend the cold end (free end) of the thermocouple to a temperature stable control room and connect it to the instrument terminals. It must be pointed out that the function of the thermocouple compensation wire is only to extend the thermoelectric electrode and move the cold end of the thermocouple to the instrument terminal in the control room. It cannot eliminate the influence of temperature changes at the cold end on temperature measurement and does not have a compensation effect. Therefore, other correction methods need to be used to compensate for the impact of cold end temperature t0 ≠ 0 ℃ on temperature measurement. When using thermocouple compensation wires, attention must be paid to model matching, polarity cannot be connected incorrectly, and the temperature at the connection end between the compensation wire and the thermocouple cannot exceed 100 ℃.

International Temperature Scale

The commonly used temperature scales internationally currently include Fahrenheit, Celsius, thermodynamic, and international practical temperature scales.

The Celsius temperature scale (℃) stipulates that at standard atmospheric pressure, the melting point of ice is 0 degrees and the boiling point of water is 100 degrees. It is divided into 100 equal parts, with each part being 1 degree Celsius and the symbol being ℃.

The Fahrenheit temperature scale (℉) stipulates that at standard atmospheric pressure, the melting point of ice is 32 degrees Celsius, the boiling point of water is 212 degrees Celsius, and there are 180 equal parts in between, with each equal part being 1 degree Fahrenheit and the symbol being ℉.

The thermodynamic temperature scale (symbol T), also known as the Kelvin temperature scale (symbol K), or the absolute temperature scale, specifies that the temperature at which molecular motion stops is absolute zero degrees.

The International Practical Temperature Scale is an internationally agreed upon temperature scale that is similar to the thermodynamic temperature scale, with high reproducibility and easy use. The currently internationally recognized temperature scale is the "1968 International Practical Temperature Scale -1975 Revised Edition" adopted by the 15th International Weights and Measures Conference in 1975, denoted as IPTS-68 (REV-75). However, due to certain uncertainties in the temperature of IPTS-68, the International Committee on Weights and Measures authorized the adoption of the 1990 International ITS-90 temperature scale to replace IPS-68 in Resolution 7 of the 18th International Conference on Weights and Measures in 1989. China has fully implemented the ITS-90 International Temperature Scale since January 1, 1994.