The principle of resistance heating of the electric heating tube of the oven

The principle of resistance heating of the electric heating tube of the oven

The oven electric heating tube is usually divided into direct resistance heating, which is very simple: the power supply voltage is directly applied to the heated object, and when the current flow expires, the heated object's own electric heating ironing machine will heat up.

The object that can be directly heated by resistance is a conductor, but it must have a higher resistivity. Because the heat occurs in the heated object itself, it is attributed to internal heating, and the thermal efficiency is very high. Direct resistance heating needs to be made of special alloy materials or non-metallic materials to make heating elements. The heat generated by the heating elements is transferred to the heated object through radiation, convection and conduction. Because the heated object and the heating element are divided into two parts, the variety of the heated object is usually not restricted, and the operation is simple.

The materials used for heating elements for direct resistance heating of the electric heating tube of the oven. The electric heating tube usually requires high resistivity, small resistance temperature coefficient, small deformation at high temperatures and not easy to embrittlement. 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 operating temperature of metal heating elements can reach 1000 to 1500°C according to the variety of materials; the operating temperature of non-metal heating elements can reach 1500 to 1700°C. The latter equipment is convenient and can be replaced by hot furnaces, but it requires pressure regulating equipment during operation, and its life span is shorter than that of alloy heating elements. It is usually used in high temperature furnaces and local and some special occasions where the temperature exceeds the operating temperature of metal heating elements.

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