The heating element inside the heating tube is mainly a resistance wire, which is a key component for converting electrical energy into thermal energy. Resistance wires are usually made of metal materials with high electrical resistivity and good heat resistance, such as nickel chromium alloys, iron chromium aluminum alloys, etc. When these materials are electrified, they generate Joule heat due to the presence of resistance, which is the heat released by the resistance of a conductor when current passes through it, thereby converting electrical energy into thermal energy.
The working principle of resistance wire in heating tube can be briefly described as follows:
Electricity input: Firstly, the external power source inputs electricity into the interior of the heating tube through the electrodes at both ends of the heating tube.
Resistance heating: When current passes through a resistance wire, due to its high resistivity, the current is obstructed during the flow process, resulting in heat generation. The magnitude of this heat is proportional to the square of the current, the size of the resistance, and the duration of the current, following Joule's law (Q=I ² Rt, where Q is heat, I is current, R is resistance, and t is time).
Heat transfer: The heat generated by the resistance wire is transferred to the outer shell of the heating tube and the surrounding medium (such as the mold) through thermal conduction, convection, and radiation. In this process, the insulation material inside the heating tube plays a key role. They not only ensure electrical insulation between the resistance wire and the shell, but also effectively transfer heat to the shell through their thermal conductivity.
Temperature control: In order to maintain a constant temperature of the mold during processing, heating tubes are usually used in conjunction with a temperature control system. The temperature control system monitors the actual temperature of the mold and compares it with the set temperature to automatically adjust the power output of the heating tube, thereby achieving precise control of the mold temperature.
In summary, the heating element inside the heating tube - the resistance wire - converts electrical energy into thermal energy through its principle of resistance heating, and transfers the heat to the mold through heat transfer, achieving heating and temperature control of the mold. During this process, factors such as the material selection of the resistance wire, resistance value, current magnitude, and the structural design of the heating tube will all affect the heating effect and efficiency.
