The solvent vapor and cracked low molecular substances generated during the baking process of the enameled wire must be discharged from the furnace in time. The density of the solvent vapor and the humidity in the gas will affect the evaporation and curing during the baking process, and the low molecular weight has an impact on the smoothness and brightness of the paint film. In addition, the concentration of solvent vapor is related to safety, so waste discharge is very important to product quality, safe production, and heat energy consumption.
Considering the product quality and safety production alone, the amount of waste should be larger, but a large amount of heat must be taken away when the waste is discharged, so the waste should be properly discharged. Catalytic combustion hot air circulation furnace usually discharges 20~30% of the hot air volume. The amount of waste discharged depends on the amount of solvent used, the humidity of the air, and the heat of the oven. For every 1kg of solvent used, about 40~50M3 of waste (converted to room temperature) needs to be discharged. From the heating of the furnace temperature, the scratch resistance of the enameled wire, and the gloss of the enameled wire, the amount of waste can also be judged. If the furnace heating is turned off for a long time, but the temperature indication value is still very high, it means that the heat generated by catalytic combustion is equal to or greater than the heat consumed by the oven, and the oven will be in a high temperature out of control state, and the amount of waste should be appropriately increased. If the furnace temperature is in the heating state for a long time, but the temperature indication is not high, it means that the heat consumption is too much, and it is likely that the amount of waste is too much. After inspection and confirmation, the amount of waste should be appropriately reduced. When the scratch resistance of the enameled wire is poor, it may be that the humidity of the gas in the furnace is too high, especially in the humid weather in summer, the humidity in the air is very high, and the moisture generated by the catalytic combustion of the solvent vapor makes the gas in the furnace. The gas humidity is higher, at this time, the amount of waste should be increased. The dew point of the gas in the furnace shall not be greater than 25°C. If the gloss of the enameled wire is poor and not bright, it is also possible that the amount of waste discharged is small. This is because the cracked low molecular substances are not discharged and adhere to the surface of the paint film, causing the paint film to lose its luster.
Smoke is a common bad phenomenon on horizontal enameled furnaces. According to the ventilation theory, the gas always flows from the point of high pressure to the point of low pressure. After the gas in the furnace is heated, the volume expands rapidly and the pressure rises. When a positive pressure appears in the furnace, smoke is emitted from the furnace mouth, which can increase the air volume or reduce the air supply volume to restore the negative pressure area. If only one end of the furnace mouth emits smoke, it is because the air supply volume at this end is too large and the local air pressure is higher than the atmospheric pressure, so that the supplementary air cannot enter the furnace from the furnace mouth, reducing the air supply volume and making the local positive pressure disappear.