Principle and advantages of assembled thermal resistance

The installation of thermal resistance as temperature measurement sensor, generally display instrument, recorder and electronic regulator supporting use, according to the provisions of the production of Pt100 platinum thermal resistance should meet the specification indexing number and meet the specification indexing number Cu50 copper thermal resistance two categories of installation type, unified design type thermal resistance.

Installation type thermal resistance is composed of temperature sensing element, external protection tube, junction box and various kinds of fixed devices, with single and double components of two standards, protection tube not only has anti-corrosion function, and has enough mechanical strength, to ensure that the product can be safely used in various occasions. Temperature measurement principle: the resistance of the heated metal wire changes with the change of temperature, and the relationship between its thermoelectric resistance value R(t) and its temperature T can be expressed as: R(t)=R0(1+At+Bt2+......) , the temperature value t can be obtained by checking the corresponding thermometer according to the measured resistance value.

Installation thermal resistance has many advantages, good decomposition of parts, convenient repair, low cost of replacing wearing parts, can transmit electrical signals far, high sensitivity, strong stability, interchangeability and accuracy are better. The normal temperature insulation resistance of platinum thermal resistance should not be less than 100M ω, and that of copper thermal resistance should not be less than 50M ω. Widely used in petroleum, chemical and other production site accompanied by a variety of flammable, explosive gas, steam occasions.

The sensor of thermal resistance is made by using the principle that the resistivity of conductor or semiconductor changes with temperature. Platinum is a precious metal, with high temperature resistance, good temperature characteristics, long service life and other characteristics, so it is widely used. Now let's introduce the classification of thermal resistance sensors.

1, NTC thermal resistance sensor:

This kind of sensor is a negative temperature coefficient sensor, that is, the resistance of the sensor decreases with the increase of temperature;

2, PTC thermal resistance sensor:

This kind of sensor is a positive temperature coefficient sensor, that is, the resistance of the sensor increases with the increase of temperature.

Thermal resistance is measured by the characteristic that the resistance of a substance changes as its temperature changes. When the resistance value changes, the working surface shows the temperature value corresponding to the resistance value.