Technical Support

Slip Ring and Thermal Resistance

Industries often need to test and control the temperature of rotary furnace and heating axis, laboratory need to test the thermal properties of new materials, we need to use thermocouples. At the same time the need to observe and record the relevant data, therefore cannot do without this slip ring assembly, but how to choose the slip ring in order to reduce errors to a minimum, it is essential for engineer.

Choosing the wrong slip ring, would cause great loss. Based on years of experience in designing thermal resistance slip ring, the following summary:
Thermal resistance is the most commonly used as a low-temperature zone temperature detector. Its main feature is high precision, stable performance. Wherein the platinum thermal resistance measurement accuracy is the highest, it is not only widely used in industrial temperature measurement, and is made standard benchmark instrument.

1. The thermal resistance measurement principle and materials
RTD temperature measurement is based on the characteristic of the metallic conductor of resistance is increased with temperature increasing. Most of the thermal resistance made from the pure metal material, is currently the most widely used platinum and copper, in addition, now begin using nickel, manganese and rhodium and other materials RTD.

2. The type of thermal resistance
Ordinary thermal resistance
From the measurement principle of thermal resistance known, the temperature change is measured directly by the change of the thermal resistance value, therefore, will change the temperature measurement of the heating resistor lead wire resistance and other impact.

Armored thermal resistance
Armored thermal resistance is a temperature sensing element (resistive element), lead, insulation materials, stainless steel casing combination of a solid body, its outer diameter is generally φ2 - φ8mm. Compared with ordinary thermal resistance, it has the following advantages: small size, no internal air gap, the thermal inertia, measuring small lag; good mechanical properties, resistance to vibration, shock; able to bend, easy to install; long service life.

Face thermal resistance
Face thermal resistance temperature sensing element by the resistance wire wound special handling, close to the end face of the thermometer. It compared with the general axial thermal resistance, it can more accurately and quickly reflect the end face of the measured actual temperature, for measuring bearings and other parts of the end surface temperatures.

Flameproof heat resistance
Flameproof thermal resistance through a special junction box structure, the explosion inside the shell by an explosive mixture due to sparks or arcing and other effects that occur confined to the junction box, the production site will not cause an explosion. Flameproof heat resistance can be used to measure the temperature of explosive dangerous places, such conditions need to use ars’s special explosion-proof slip rings.

Depending on the different type of thermocouple and RTD, the requirements to slip ring are different, cosmau developed a slip ring is suitable for thermocouple, RTD, for different requirements, using different slip ring contact materials, structures, wires and so on. Make sure the temperature errors to a minimum. At the same time depending on the temperature environment, as well as available high temperature slip ring, low temperature slip rings.

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