Principle of air heater resistance heating

The air heater uses the Joule effect of the current to convert electrical energy into thermal energy to heat the object. Usually divided into direct resistance heating and direct resistance heating. The former's power supply voltage is directly applied to the object to be heated. When the current flow is overdue, the heated object itself heats up the ironing machine to generate heat. Objects that can be directly resistively heated need to be conductors, but have a higher resistivity. Since heat is generated by the object itself being heated, it is highly heated due to internal heating. Direct resistance heating needs to be made of special alloy materials or non-metal materials to produce heating elements. The heating elements generate heat energy, and the radiation, convection and conduction are transmitted to the heated object.

Since the object to be heated and the heating element are divided into two parts, the type of the object to be heated is usually not bound, and the manipulation is simple. The data used for the heating element of direct resistance heating usually requires a large resistivity and a small temperature coefficient of resistance, and is small in deformation at high temperature and is not easily embrittled. Commonly used are metal materials such as iron-aluminum alloy and nickel-chromium alloy, and non-metal materials such as silicon carbide and molybdenum disilicide. The highest operating temperature of metal heating elements can reach 1000-1500 °C depending on the type of data; the highest operating temperature of non-metallic heating elements can reach 1500-1700 °C. The latter is easy to deploy and can be replaced by a hot furnace. However, it requires equipment to be installed in the pressure regulation setting. The life is shorter than that of the alloy heating element. It is usually used in high temperature furnaces, and the temperature exceeds the metal data. The heating element allows the highest operating temperature to be local. And some extra places.