Luoyang Judian Metal Hot Processing Equipment Co., LTD is mainly engaged in the manufacture of complete sets of equipment in the metal thermal processing industry and the integration of the entire production line.
If each exposed surface of the charge receives an equal amount of heat per unit time, then temperature uniformity is achieved for all parts of the furnace. This statement applies to intermittent furnaces.
In continuous furnaces, the temperature distribution along the width of the furnace must be uniform. It should also be pointed out here that for some processes, uniformity of temperature in the furnace does not produce the best results.
Induction furnace
There is an example to prove the correctness of this statement. On a diameter expansion mill, all parts of a long tube should arrive at the mill at the same temperature. Therefore, the rear of the steel tube must be hotter than the front when it comes out of the furnace. The steel tube rolls out from the side of the furnace.
True uniformity in all parts of the furnace is difficult to achieve by automatic control alone. The purpose of automatic control is the result of good furnace design and good operation.
The following factors affect the uniformity of temperature in the furnace: the arrangement of the electric heating elements or radiant tubes, the uniformity of the temperature of each radiant tube, the arrangement of the burners, the type of burners (bright flame or transparent flame), the speed and direction of the combustion products causing the circulation, forced circulation, the height of the burners and the furnace roof above the upper part of the charge (in high-temperature furnaces), the arrangement of the heating tunnels, the exhaust ports, and the muffle walls.
Operating factors are: the placement of the charge, the adjustment of the burners, and the closing of some burners during the heating process. Temperature uniformity is easy to obtain in certain heating processes that do not require a furnace. If the current is passed through a bar of constant cross-section, the temperature rise is the same along the length of the bar except at the ends of the bar.
The same effect can be obtained if the current is generated by the induction of alternating current in a coil around the bar. Most of the design factors that contribute to uniform temperature in the furnace have been discussed in the sections "Capacity of the Muffle Furnace" and "Gas Movement" in the previous volume.
Other factors are discussed in Chapter 2 of this book. Some other factors will be discussed below. In a high temperature furnace, if the burner is located higher above the furnace floor, the heat flow into the charge will be more uniform than if the burner is located closer to the charge. In a high temperature furnace, it is rarely effective to install only one high-position burner.
