Classification And Performance Characteristics Of Hot Runner Heating Coils
Resistance heating coil: Use the Joule effect of current to convert electrical energy into heat to heat objects. It is usually divided into direct resistance heating and indirect resistance heating. Commonly used are metal materials such as iron-aluminum alloy and nickel-chromium alloy and non-metallic materials such as silicon carbide and molybdenum disilicide. The maximum working temperature of metal heating element is 1000~1500℃ according to the type of material; the maximum working temperature of non-metal heating element can reach 1500-1700℃.
Induction heating coil: the conductor itself is heated by the thermal effect formed by the induction current (eddy current) generated by the conductor in the alternating electromagnetic field. According to the power of the heating equipment and the capacity of the power supply network, a high-voltage power supply (6-10 kV) can be used to supply power through a transformer; the heating equipment can also be directly connected to a 380-volt low-voltage power grid.
Arc heating coil: Use the high temperature generated by the arc to heat the object. Arc is a gas discharge phenomenon between two electrodes. The characteristics of arc heating are: high arc temperature and concentrated energy. The surface power of the molten pool of the steel-making electric arc furnace can reach 560~1200 kW/m2. However, the arc noise is large, and its volt-ampere characteristics are negative resistance characteristics (descent characteristics).
Infrared heating coil: Use infrared radiation to radiate an object. After the object absorbs infrared, it converts the radiant energy into heat and is heated. Infrared is a kind of electromagnetic wave. In the application of infrared heating, a suitable infrared radiation source must be selected according to the type of the heated object, so that the radiation energy is concentrated within the absorption wavelength range of the heated object to obtain a good heating effect.
