Mar 21, 2022
Before using the heating wire, you should know its heating principle, which is: when the current passes through the resistance, the current does work and consumes electric energy to produce heat. This phenomenon is called the thermal effect of current. Practice has proved that the heat generated by the current passing through the conductor is directly proportional to the square of the current, the resistance of the conductor itself and the time of the current passing. This is the conclusion reached by British scientist Joule and Russian scientist Lenz, which is called Joule's law and Lenz's law.
Moreover, the electric heating wire should have appropriate resistivity to achieve the purpose of power on and heating. If the resistivity is too large or too small, it needs very short or very long, very thin or very thick electric heating wire, so it is difficult to manufacture and use electric heaters of large and small power; The melting point should be relatively high. You can't melt when you get hot.
When the temperature is high, the chemical stability is relatively high. It can not be oxidized quickly and the service life is very short. At present, commonly used are: nickel chromium wire, iron chromium wire, pure nickel wire, constantan wire, Kama wire, copper nickel wire, stainless steel, new constantan, manganese copper, Monel, etc. The power of 220V / 5A resistance wire is 1100W.
The requirements of electric heating pipe for internal electric heating wire are as follows:
1. Sufficient heat resistance, i.e. no oxidation or little oxidation at high temperature;
2. It has certain mechanical strength at high temperature;
3. The specific resistance is large, otherwise the electric heating tube has to be made very long, which is inconvenient to install;
4. The smaller the resistance temperature coefficient, the better;
5. Good processing performance, can be processed into linear, ribbon or spiral shape, and has good welding performance;
6. No aging after working for a long time;
7. The material source is based on China and the cost is low. Of course, imported electric heating wires can be used for electric heating tubes with high requirements.
