After the wire is painted and baked in the oven, it is the most important stage in the painting process. In the lower part of the vertical furnace, the solvent evaporates from the paint layer; in the upper part of the furnace, a chemical reaction occurs to form an insulating film. The wire is heated too much in the lower part of the furnace, causing the solvent to boil and cause waste. The wire in the upper part of the furnace too hot, the paint will be thermal oxidation degradation phenomenon. And the wire in any section of the furnace heat shortage, cross-linking and film-forming process will slow down slowly. Therefore, the furnace wall along the height of the temperature field Tc (h), for the furnace heat transfer medium along the height of the temperature field TB (h) and wire coating speed V should maintain a certain relationship to ensure that the paint wire baking required temperature. The increase in the heating power of the lower part of the furnace and the installation of the electric heating element along the entire height of the furnace can increase the production efficiency of the live charter type machine by 1.3 to 1.5 times.
It is pointed out that the temperature field of the furnace wall, the heat exchange medium and the furnace shell can be approximated by the mathematical model of the integral differential equation. The temperature field of the oven is determined as follows: %. It is concluded that it is the most reasonable solution to improve the productivity and reduce the energy consumption by returning the wire from the upper guide wheel to the furnace without the furnace under the existing equipment structure.
As the wire length of the painted wire increases in the furnace, the length of the wire in the solvent evaporation zone and the cured film zone of the oven is reduced. Thus, as the wire speed increases, it is necessary to increase the temperature of the wire to reinforce the physical-chemical process in the coating to compensate for the reduction in residence time of the wire in the furnace. However, the thermal oxidation degradation in the coating at high temperatures leads to a sudden increase in the risk of gas impurities, as well as the working capacity of the heating elements and insulation materials, and limits the wire temperature. It is pointed out that the improvement of the production efficiency of the C-24 enameled charter is related to the increase of the electric energy consumption due to the improvement of the oven temperature field.
Therefore, in order to further improve the production efficiency of the C-24 and B-30 type charter, the most reasonable solution is to re-enter the furnace from the upper guide wheel without the furnace under the existing structure. This is equal to the furnace length has doubled. The graphs in the figures show that the possibility of coating copper wires with the above scheme is well established.
When the wire through the enamel furnace furnace return movement, the repeated use of heat transfer media in the exhaust hood area of ​​the heat; increase the paint wire in the enamel furnace stagnation time; wire return movement, the wire and heat transfer The medium moves in the opposite direction, making the convective heat exchange strong. As the thermal balance of the enameled furnace is improved, the productivity is improved and the power consumption rate is reduced.