GB2060847A - Pre-fabricated beam element for self-supporting flat vaults of tunnel-type furnaces - Google Patents

Abstract

There is described a prefabricated beam element (1) for the construction of the self-supporting flat roof of a tunnel-type furnace. The element, of a refractory concrete, has a substantially reversed T-shaped cross-section and is formed with a central through hole (3) defined by a tubular metal sheet (4), preferably of rectangular cross- section. Between the tubular metal sheet and the concrete material there is provided a thermo-insulating sheath (5), preferably of ceramic fibers. <IMAGE>

Description

SPECIFICATION Pre-fabricated beam element for self-supporting flat vaults of tunnel-type furnaces The present invention relates to a pre-fabricated beam element for self-supporting flat vaults of tunnel-type furnaces or kilns, in particular for baking bricks and ceramic products or in iron metallurgy.

Tunnel-type furnaces with flat vault or roof are known in the art, in particular of the selfsupporting type, as described in British Patent No. 1 502499. This vault or roof is comprised of a multiplicity of rectilinear beams, positioned in a transverse direction with respect to the feed of the material to be baked and resting with their ends on the side walls of the tunnel. Each beam comprises a core or inner metallic tubular reinforcement, generally formed as an H-beam, having air-tight sealed walls with a sheath of thermo-insulating material all around, so as to utilize such a core not only for its bearing and reinforcing functions, but also as a conduit of a cooling system provided at the outside.

Although according to the above-mentioned patent each beam may be formed of a number of beam sections of refractory material which are bound together by expansion joints, the beams of this type have been so far manufactured by means of a single casting of refractory concrete (having different characteristics according to the temperatures to withstand) around the inner reinforcement already coated with the insulating sheath, while preferably severing the casting into a plurality of transverse sections, then bound together by expansion joints. This of course has the drawback of producing, storing, handling and transporting to the installation place beams of considerable weight and length (up to 3 m and more), with the danger of ruptures or cracks in the finished product and malformations of the beam contour during the casting and the subsequent curing.

On the other hand it is unthinkable that single beam elements are manufactured, each of them provided with inner reinforcement and insulating sheath, since it would be extremely difficult and expensive to connect each other the various H-beam sections.

The object of the present invention is a prefabricated beam element capable of overcoming the above-mentioned inconveniences, as it can be "slipped on" around the metallic core at the place of installation of the tunnel kiln, in a sufficient number to complete the required length of beam.

In order to enable this "slipping", each beam element is formed with a longitudinal through hole defined by four walls of metal sheet with a sheath of insulating material all around. The purpose of the inner sheet is that of reducing the friction with the metal core, generally an iron H-beam with closed walls, during the mounting of the pre-fabricated beam elements thereon for the assembly of a beam.

The advantage of producing single smaller elements is obtained, thus with a more accurate formation and being lighter. Therefore the handling and transportation problems are reduced, with less important dangers of cracks and breakages and the possibility of massproducing these elements with various standard lengths, thus rendering it possible to obtain beams of the desired size, simply conveniently choosing the number and the size of the elements to be mounted on a given length of a H-beam.

These and further objects, advantages and features of the present invention will be understood from the following detailed description of an embodiment thereof, given by way of a non-limiting example with reference to the annexed drawings, in which: Figure 1 is a cross-section view of a beam element of the present invention; and Figure 2 is a perspective view of two elements of Fig. 1 mounted one near the other on a central metallic reinforcement core.

With reference to Fig. 1, the beam element 1 according to the present invention has a substantially reversed T-shaped cross-section with a lower base 2 and a central through hole 3 defined by a metal sheet 4 which is relatively thin and surrounded by an insulating material sheath 5. The sheath 5, generally being of ceramic flock or rock wool, keeps the sheet 4 separated from the refractory concrete of which the body of element 1 is made.

Therefore the beam element 1 may be easily manufactured by means of a casting of concrete material having the desired refractory properties in a mold of proper size, around a tubular section of sheet iron, preferably of quadrangular cross-section, which has been coated with an insulating sheath, such as of ceramic fibers.

With reference to Fig. 2, it is seen how these beam elements are easily mounted merely causing them to slip on around a central core 6 which, as already mentioned, not only is the beam supporting member, but also forms a conduit of the cooling system.

The sliding of each element 1, 1' along the core 6, which preferably consists of a H-beam with closed tubular walls, is considerably made easier by the reduced friction between the reinforcing core 6 and the metal sheet 4.

Therefore it will be sufficient to slip on a proper number of elements 1, 1', etc. with intermediate expansion joints 7, around a reinforcing core 6 of the desired length, corresponding to the width of the tunnel type furnace being built, to have the finished beam, ready to be mounted and connected with the cooling system. By suitably choosing various standard sizes of the beam elements to be mass-produced and stored, it is possible to obtain furnace beams of different length merely combining a certain number of elements together, even of different length.

Claims (4)

1. A pre-fabricated beam element for selfsupporting flat vaults of tunnel-type furnaces, having a substantially reversed T-shaped crqss-section and made of refractory concrete material, characterized by the fact of comprising a central throughhole defined by a tubular metal sheet with relatively thin walls being surrounded by an insulating sheath directly in contact with said refractory concrete material.

2. A beam element according to claim 1, wherein said tubular metal sheet has a quadrangular cross-section.

3. A beam element according to claim 1, wherein said insulating sheath is formed with ceramic fibers.

4. A beam element for self-supporting flat vaults of tunnel type furnaces, substantially as above described and illustrated in the annexed drawings.