The difference between armored thermal resistance and platinum resistance temperature instruments

The difference between armored thermal resistor and platinum resistance temperature instrument
Although armored thermal resistor is widely used in industry, its application is limited by its temperature measurement range. The temperature measurement principle of thermal resistor is based on the characteristic that the resistance value of conductor or semiconductor changes with the temperature. It has many advantages. It can also transmit electrical signals remotely, has high sensitivity, strong stability, good interchangeability and accuracy, but requires power excitation and cannot measure temperature changes instantaneously. Industrial thermal resistors generally use Pt100, Pt10, Cu50, Cu100. The temperature measurement range of platinum thermal resistors is generally minus 200-800℃, and that of copper thermal resistors is minus 40 to 140℃. Thermal resistors are distinguished by the same type as thermocouples, but they do not require compensation wires and are cheaper than thermocouples.

Platinum resistors, referred to as platinum thermal resistors, have resistance values that change with temperature. It has a series of products such as PT100 and PT1000.

The 100 after PT means that its resistance is 100 ohms at 0℃, and its resistance is about 138.5 ohms at 100℃. Its working principle: When PT100 is at 0 degrees Celsius, its resistance is 100 ohms, and its resistance will increase at a uniform rate as the temperature rises. The difference between armored thermal resistor and platinum resistance temperature meter

From the temperature measurement principle of thermal resistor, it can be known that the change of the measured temperature is directly measured by the change of the resistance of the thermal resistor. Therefore, the change of various wire resistances such as the lead wire of the thermal resistor will affect the temperature measurement.

The armored thermal resistor is a solid body composed of a temperature sensing element (resistor), lead wire, insulating material, and stainless steel casing. Its outer diameter is generally φ2-φ8mm, and the smallest can reach φ0.25mm. Compared with ordinary thermal resistors, it has the following advantages:

① Small size, no air gap inside, small measurement value due to thermal inertia;

② Good mechanical properties, vibration resistance, and impact resistance;

③ Can be bent and easy to install;

④ Long service life.

Armored thermal resistors are commonly used temperature measuring elements in temperature measuring instruments. When the two ends of two conductors of different components are connected into a loop, when the temperatures of the two junction thermocouples are different, a thermal current will be generated in the loop. If there is a temperature difference between the working end and the reference end of the thermocouple, the display instrument will indicate the temperature value corresponding to the thermoelectric potential generated by the thermocouple.

Armored thermal resistor couple is a temperature sensor. It has a smaller diameter than assembled thermocouples, is easy to bend, and has good shock resistance. It is suitable for installation in places where assembled thermocouples cannot be installed. The armored thermocouples produced by the company use imported thermal resistor temperature measuring elements. Therefore, it has the advantages of accuracy, sensitivity, fast thermal response time, stable quality, and long service life.