Heating Coil Introduction
Converting electrical energy into thermal energy to heat objects. It is a form of electrical energy utilization. Compared with general fuel heating, electric heating can achieve higher temperatures (e.g., arc heating can reach temperatures above 3000°C), and it is easy to realize automatic temperature control and remote control, vehicle-mounted electric heating cup.
It can maintain a certain temperature distribution of the heated object as needed. Electric heating can generate heat directly inside the heated object, thus having high thermal efficiency, fast heating speed, and can achieve overall uniform heating or local heating (including surface heating) according to the heating process requirements. It is easy to realize vacuum heating and controlled atmosphere heating. During the electric heating process, less waste gas, residue, and smoke are produced, keeping the heated object clean and not polluting the environment. Therefore, electric heating is widely used in production, scientific research, and testing fields. Especially in the manufacturing of single crystals and transistors, mechanical parts and surface quenching, smelting of ferroalloys, and manufacturing of artificial graphite, electric heating methods are adopted.
Classification by Working Mode
According to different methods of electrical energy conversion, electric heating is usually divided into resistance heating, induction heating, arc heating, electron beam heating, infrared heating, and dielectric heating.
Resistance Heating Coil
Using the Joule effect of current to convert electrical energy into thermal energy to heat objects. It is usually divided into direct resistance heating and indirect resistance heating. In the former, the power supply voltage is directly applied to the heated object, and when current flows, the heated object itself, electric heating ironing machine.
generates heat. Objects that can be directly resistance heated must be conductors but have high resistivity. Since heat is generated within the heated object itself, it is internal heating with high thermal efficiency. Indirect resistance heating requires special alloy materials or non-metallic materials to make heating elements, which generate heat and transfer it to the heated object through radiation, convection, and conduction. Since the heated object and the heating element are separate, the type of heated object is generally not limited, and operation is simple.
The materials used for heating elements in indirect resistance heating generally require high resistivity, low temperature coefficient of resistance, small deformation at high temperatures, and not easy to become brittle. Commonly used are metal materials such as iron-chromium-aluminum alloys and nickel-chromium alloys, and non-metallic materials such as silicon carbide and molybdenum disilicide. The maximum working temperature of metal heating elements can reach 1000~1500°C depending on the material; the maximum working temperature of non-metallic heating elements can reach 1500~1700°C. The latter is easy to install and can be replaced while the furnace is hot, but it requires a voltage regulating device during operation and has a shorter lifespan than alloy heating elements. It is generally used in high-temperature furnaces, places where the temperature exceeds the maximum working temperature allowed for metal material heating elements, and some special occasions.
