The structure and characteristics of the centralized heating furnace

A solid bottom furnace is a type of furnace in which the billet is heated on a solid bottom. All the heat required by the billet is supplied by the upper part. Since only one side is heated, this type of furnace is usually only used for heating small-section billets and round tube billets, and the production is low, and usually one-stage or two-stage heating is used. Since there is no bottom water pipe, the insulation is better, so this type of furnace still has a future in energy saving through reform.

The two-stage furnace is divided into a preheating section and a heating section along the length of the furnace. The function of the preheating section is to use the high-temperature flue gas from the heating section to preheat the billet to save feed. The two-stage furnace is generally suitable for heating small-section billets. The billet has almost no equalizing time in the furnace and is always in the heating stage. The temperature gradually decreases along the length of the furnace. Since there is no equalizing section, the temperature difference between the inside and outside is large when heating large-section billets. In terms of furnace structure, there is no obvious boundary between the furnace waist and the furnace head of this furnace at the height of the furnace top.

The temperature distribution of the three-stage furnace is different from that of the two-stage furnace. The temperature of the heating section rises, and the billet heats faster in this section. The temperature difference on the cross section is also larger. The billet must be heated in the equalizing section before it can be discharged. The billet is heated slowly in the equalizing section, or the surface temperature of the billet is maintained unchanged to increase the internal temperature of the billet. Since the billet does not absorb a lot of heat in the equalizing section, the furnace temperature is slightly lower than that in the heating section.

Obviously, the three-stage furnace has higher output and better heating quality than the two-stage furnace, and is suitable for heating thicker billets. Compared with the two-stage furnace, the heating section and the equalizing section of this type of furnace have obvious boundaries in terms of furnace structure. In terms of burner configuration, the waist furnace provides more heat and the head furnace provides less.