JPH0116763Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a heating furnace for steel billet materials, etc., which has a preheating zone without a burner.

In a conventional metal heating furnace, for example, as shown in FIGS. 1 and 2, a slab b in a heating furnace a is
are a preheating zone d, a heating zone e, and a heating zone e divided by a partition wall j.
While moving through the soaking zone f as indicated by arrow i,
Heated to 900-1200℃. The heating zone e and the soaking zone f have a ceiling burner g and a side burner h, but there is no burner in the preheating zone d, and the high temperature exhaust gas of 800 to 1000 degrees Celsius flowing from the heating zone e burns the top of the slab support c. Preheat slab b. In other words, the conventional preheating zone d is as shown in Fig. 1, and since the gas flow k flows only through easy-to-flow areas, large temperature stratification due to gas accumulation and draft occurs in the height direction of the preheating zone d. The effective gas radiation diameter was small, and the ceiling and hearth temperatures were lower than the gas temperature, so the effective rate of heat transfer was low. In addition, because the cross section within the preheating zone d was uniform and wide, the gas flow velocity was low at about 0.5 meters per second, and the amount of convective heat transfer was small. On the other hand, in order to improve the heat transfer efficiency of the preheating zone d, there is a jet preheating zone in which the exhaust gas is jetted onto the slab by a fan, but in this case, the power of the fan increases and the equipment cost increases, especially in hot charge slabs. The heat resistance of the fan is low, up to about 500℃.
This caused problems such as unusability. Furthermore, when the height H of the preheating zone d was lowered to increase convective heat transfer, the gas layer thickness decreased and the amount of radiation heat transfer decreased.

The present invention provides a preheating zone that does not require a fan, does not require a fan, and can mix well and reach a high temperature by providing alternating buttful plates, thereby increasing the amount of radiant heat transfer. This is the purpose.

For this reason, the configuration of the present invention is such that in the preheating zone of the heating furnace where no burner is provided, a buttful plate with a distance between it and the ceiling to allow the gas flow to pass through, and a buttfull plate that is in close contact with the ceiling are connected to the heated material. A group of upper buttful plates are arranged alternately in the direction of movement of the heated material, and the buttful plates are provided with a distance between them and the hearth for gas flow to pass through, and the buttful plates in close contact with the hearth are used to heat the heated material. The present invention is characterized in that it comprises lower baffle plate groups arranged alternately in the traveling direction of the vehicle, and the number of plates in the upper buffle plate group is greater than the number of plates in the lower buffle plate group.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 3 to 5.

3 and 4 show an embodiment of the present invention, in which 1 is a preheating zone, 2 is an arrow indicating the gas flow from the heating zone 11, 3 is a slab of the material to be heated, 4 is a slab support pipe, and 5 and 6 are buttful plates installed on the ceiling and hearth, respectively.

That is, the preheating zone 1 includes a double plate 5 having separate gas passages m between the ceiling and the hearth;
Batchful board 6 that adheres to the ceiling and hearth separately
are provided alternately in the advancing direction of the slab 3 (longitudinal direction of the furnace) over the entire surface in the furnace width direction.

The double plates 5 and 6 are made of heat-resistant metal, fire-resistant material,
Ceramic fiber is a good material to block gas radiation from the upstream side. Further, as shown in FIG. 4, the upper buttful plate 5 is supported by a heat-resistant metal hanging rod 7, and the lower buttful plate 5 is supported by a pillar 8 made of a fire-resistant material.

In this way, the upper and lower butt-full plates 5 provide a distance m between the ceiling and the hearth for each gas flow to flow out gas near the ceiling and the hearth, and the upper and lower butt-full plates 6 connect to the ceiling and the hearth. The gas flow is caused to flow along the slabs 3 at a high speed, each in close contact with the hearth. The flow of these gases is indicated by arrow 2.
In addition, because the low temperature gas near the hearth, especially the low temperature gas near the ceiling, is moved quickly, the gas in the preheating zone 1 is always at a high temperature, increasing heat transfer, and the gas flow at the free end of the buttful plate 6. flows at high speed, increasing convective heat transfer.

In Figure 5, the horizontal axis shows the gas temperature in the direction of the arrow, and the vertical axis shows the height H of the preheating zone shown in Figures 1 and 3.The dotted line 9 indicates the temperature of the conventional type without a full plate. The solid line 10 shows the temperature distribution of the present invention. In the present invention, this is the full plate 5.
and 6 are provided alternately, which means that the gases are sufficiently mixed, the diameter of the gas mass increases, and radiation heat transfer increases.

In addition, since the lower gas flow tends to rise to the upper part due to draft, in this invention, the number of plates in the upper buttful plate group is greater than the number of plates in the lower buttfull plate group. Although there are two plates 6, there is only one buttful plate 6 that is in close contact with the hearth, so that the pressure loss in the upper part is greater than the pressure loss in the lower part, and the gas flow in the upper and lower parts is equally divided. . Further, the height H of the preheating zone 1 is about 1.5 to 2.5 meters, and the higher the height, the better the efficiency, but if it exceeds 2.5 meters, the rate of increase in efficiency decreases. Further, the distance m through which the gas flow passes through the baffle plate 5 depends on the balance with the pressure loss in the preheating zone, but in general use, it is approximately 1/3 of the length n of the buffle plate 5 in the height direction. Moreover, the relationship between the distance l between the baffle plates 5 and 6 and the length n is efficient, that is, l/n is 1 to 3.

As described above, according to the present invention, one of the upper and lower buttful plates is provided with a distance between the ceiling and the hearth to allow the gas flow to flow separately, so that the gas near the ceiling and the hearth is flowed out, and the other upper and lower The buttful plate is in close contact with the ceiling and the hearth separately, allowing the gas flow to flow along the heated material at a high speed, so the low temperature gas near the ceiling and hearth is moved quickly, and the gas inside the preheating zone is moved quickly. The gas is always hot, heat transfer increases,
The gas flow at the free end of the buttful plate, which is in close contact with the ceiling and hearth, respectively, flows at high speed, increasing convective heat transfer. Moreover, since the one baffle plate and the other buffle plate are arranged alternately in the direction of movement of the material to be heated, the gases are sufficiently mixed, the diameter of the gas mass increases, and radiation heat transfer increases. In addition, the low temperature gas near the ceiling and hearth is flushed out, and the high temperature gas flows in, resulting in radiant heat transfer.
When will it increase? In particular, by increasing the number of upper buttfull plates than the number of lower buttfull plates,
Unbalanced flow between the upper and lower gases is eliminated, improving heat transfer.

[Brief explanation of drawings]

Fig. 1 is a sectional side view of a conventional heating furnace, Fig. 2 is a sectional front view of Fig. 1, Fig. 3 is a sectional side view showing an embodiment of the present invention, and Fig. 4 is a sectional side view of Fig. 3. Cutting line A
FIG. 5, which is a cross-sectional front view taken along line -A, is an explanatory diagram of the gas temperature distribution in the preheating zone. 1... Preheating zone, 2... Arrow showing the flow of gas from the heating zone, 3... Slab as heated material,
4... Slab support pipe, 5, 6... Bound full board, 7... Bound full board hanging rod, 8... Bound full board support, 11... Heating zone.

Claims (1)

[Scope of utility model registration request] In a heating furnace that has a preheating zone without a burner, the preheating zone has a buttful plate with a distance between it and the ceiling to allow the gas flow to pass through, and a buttfull plate that is in close contact with the ceiling to allow the material to be heated to advance. The upper buttle plates are provided with a group of upper buttress plates arranged alternately in the direction, and the buttle plates are provided with a distance between them and the hearth for gas flow to pass through, and the buttle plates that are in close contact with the hearth are arranged to prevent the progress of the material to be heated. Equipped with a group of lower buttful plates arranged alternately in the direction,
Moreover, the heating furnace is characterized in that the number of plates in the upper buff full plate group is greater than the number of plates in the lower buff full plate group.