The heating methods of the oven include electric heating, combustible gas heating, oil heating and coal heating.
1. Electric heating
Electric heating methods include electric furnace wire heating, infrared plate heating, infrared tube heating, infrared furnace heating and induction heating. In the hot blast stove with electric heating method, in order to make the temperature distribution in the furnace even, it is generally equipped with a blower for blast circulation. In the infrared furnace, in addition to a part of the electric energy being directly converted into heat energy and transmitted to the workpiece by convection, there is also a part of infrared energy transmitted to the workpiece by radiation. The proportion of heat energy and radiation energy of infrared heating elements with different structures is different. The coated object of powder coating will heat up from the inside when it is subjected to infrared radiation, and it will heat up from the outside when it is subjected to heat energy, so the heating speed is faster. However, due to the uneven temperature distribution in this type of baking oven, the farther away from the heat source, the lower the temperature, and when the size and shape of the object to be coated are different, the amount of heat received by different parts is also different, so the baking and curing effects are significantly different, resulting in The film cures unevenly. This type of baking oven is only suitable for the baking of flat plate-shaped or simple drum-shaped objects that can be rotated in the oven, but not for the baking of workpieces with complex shapes.
2. Hot Air Oven
Including baking ovens that use hot air generated by burning coal gas, natural gas, oil, and coal for baking. The advantage of the hot air baking furnace is that the temperature distribution in the furnace is relatively uniform, the temperature is easy to control, and it is suitable for baking coated objects of various shapes and sizes. However, since the heat transfer effect of the hot air is carried out from the surface to the inside, the coating film is formed from the surface to the inside. The object to be coated heats up slowly. In addition, the combustion residue in the hot blast stove and the dust in the air are easy to contaminate the coating film.
Which heat source to use should be determined according to the actual situation of local energy sources. For example, electric heating should be used in areas with abundant power resources and low prices. In areas where electricity is scarce but oil and gas resources are relatively abundant (such as the southeast coastal areas of our country), oil heating or combustible gas heating can be used. The cost of coal-fired heating furnace is lower, but there are problems that the temperature is not easy to control, and the product quality is easily affected by combustion residues and dust pollution, so this heating method is only used when other energy sources are in short supply.
