Composition of thermal resistance temperature measurement system

(1) Thermistor temperature measurement system generally consists of a thermal resistor, connecting wires and a display instrument.
The following two points must be noted:
① The thermal resistor and the display instrument must have the same graduation number
② In order to eliminate the influence of the resistance change of the connecting wire, a three-wire connection method must be adopted. For details, please refer to Chapter 3 of this article.

(2) Armored thermal resistor The armored thermal resistor is a solid body composed of a temperature sensing element (resistor body), lead wire, insulating material, and stainless steel casing. Its outer diameter is generally φ1~φ8mm, and the minimum can reach φmm. Compared with ordinary thermal resistors, it has the following advantages:
① Small size, no air gap inside, small measurement lag in thermal inertia;
② Good mechanical properties, vibration resistance, and impact resistance;
③ Can be bent for easy installation
④ Long service life.

(3) End face thermal resistor The end face thermal resistor temperature sensing element is wound with specially treated resistance wire and is tightly attached to the end face of the thermometer. Compared with general axial thermal resistors, it can more accurately and quickly reflect the actual temperature of the measured end face, and is suitable for measuring the end face temperature of bearings and other parts.

(4) Flameproof thermal resistors Flameproof thermal resistors use a special structure of the junction box to isolate the explosive mixed gas inside its shell from the impact of sparks or arcs. The circuit breaker repair of the resistor body will inevitably change the length of the resistor wire and affect the resistance value. Therefore, it is better to replace the resistor body with a new one. If welding is used for repair, it must be calibrated and qualified before use.