JPS6047510B2 - Furnace structure - Google Patents

Description

[Detailed description of the invention] This invention relates to a furnace body structure using dry refractories.

Wet refractories are hardened onto the inside of the outer shell of the furnace body by adding a binder (refractory cement, water, water glass, etc.).

For this reason, it was used for complex-shaped furnace bodies such as groove-shaped induction furnaces. Because wet type refractories are solidified in one piece, they have high thermal conductivity, lowering the thermal efficiency of the furnace, and have the disadvantage that cracks can extend over the entire furnace wall. Furthermore, if the work of hardening the wet refractories on the inside of the outer panel was interrupted, the difference in humidity between the front and back refractories would create a layer that was prone to cracking, so the work had to be continued for a long time. Another drawback was that it took a long time to dry the refractories. Dry type refractories do not have the disadvantages of wet type refractories mentioned above, but due to the high sintering temperature, items with complex shapes often break due to the difference in thermal expansion during sintering. .

This invention eliminates the above-mentioned exclusion points and has good thermal efficiency.
To provide a furnace body structure in which tamping work of refractories can be interrupted without cracks extending over the entire furnace wall, long-time drying is unnecessary, and moreover, there is no damage during sintering. According to the present invention, the above object is achieved by providing a furnace structure having an outer dry refractory layer with a low binder content and an inner dry refractory layer with a high binder content. I was able to reach it.

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a partial sectional view of a furnace structure according to an embodiment of the present invention. An asbestos layer 2 is provided on the inner surface of the outer panel 1 to retain heat and absorb thermal expansion. A dry refractory (e.g. Al2O3-MgO) 3 with a low content of binder (e.g. boric acid) (approximately 0.5%) on the inner surface of the asbestos layer 2
A layer of dry refractory (Al.O.-MgO) 4 with a high binder (boric acid) content (approximately 1%) is formed inside the layer. The inner surface of the dry refractory layer 4 is in contact with the molten metal 5. Next, the method of constructing the furnace shown in Fig. 1 will be explained with reference to Fig. 2.

A formwork 7 provided with a large number of small holes 6 is fixed at a distance j from the asbestos layer 2 by the thickness of the layers of dry refractories 3 and 4. A partition plate 8 is positioned between the asbestos layer 2 and the formwork 7, a dry refractory 3 is placed between the asbestos layer 2 and the partition plate 8, and a dry refractory 4 is placed between the formwork 7 and the partition plate 8. Insert each
The partition plate 8 is gradually moved upward while compacting. By repeating such operations, dry refractories 3 and 4 are filled between the asbestos layer 2 so that the layer of dry refractory 3 is located on the outside and the layer of dry refractory 4 is located on the inside. do. Then, the dry refractories 4 are sintered by heating from the side of the formwork 7, and after the formwork 7 is removed, the furnace body is used for use. In the furnace body structure according to the present invention described above, the dry refractory 4 located inside has a high content of binder, so the temperature is low (700 ~
750°C).

Therefore, even if the mold has a complicated shape, it will not be damaged during sintering, and the mold 7 can also be used for the next furnace construction. In addition, since the layer of dry refractory 3 with a low binder content is located on the outside, it has high fire resistance, and even when the heat of the molten metal 5 is transferred during use, the dry refractory 3 is not sintered to a large extent. is left behind. Therefore, the thermal conductivity is low and the thermal efficiency of the furnace is high. Moreover, cracks do not extend to the entire furnace wall. In addition, dry type refractories allow the tamping work to be interrupted during furnace construction and do not require long drying times.

[Brief explanation of the drawing]

FIG. 1 is a partial cross-sectional view of a furnace structure according to an embodiment of the present invention, and FIG. 2 is a partial cross-sectional view showing a furnace construction method of the furnace structure shown in FIG. 1. 3,4...Dry refractories.

Claims (1)

[Claims] 1. A furnace structure characterized by comprising an outer dry refractory layer with a low binder content and an inner dry refractory layer with a high binder content.