Technical field

The present invention relates to a protection module, part of the cooling piping of industrial furnaces for heating steel semifinished products, like slabs, billets, pipes or steel sheets. These furnaces usually comprise a bearing structure made of pipes, cooled by water or other cooling fluids. Said pipes need to be covered by a refractory coating to reduce heat losses, that is, heat absorptions by the cooling fluid. According to a preferred embodiment, the refractory coating is made of a metallic structure (steel sheet or wire net), prefabricated concrete and a thin layer of ceramic fiber and/or other insulating material between the steel sheet and the concrete. Generally, pasty slag accumulates in the heating and discharge areas of these furnaces, detaching from the slab surface, it falls into the hollows, along which the movable pipes, i.e. the moving frame of the heat charge, translates. The hollows' clogging often causes accidental stops of the furnace to clean the channels under the furnace bottom. Moreover, in this area of the furnace, where the highest temperatures are reached to obtain a suitable heating of the metallic charge, it is very important to avoid heat losses. These

hollows on the furnaces bottom causes continuous heat loss. For this reason the movable vertical pipes of said cooling piping need specific protection profiles. These profiles are aimed at forming a protecting umbrella to avoid the falling of the slag, produced by the furnace charge (slabs, billets, and similar), into the hollows and, consequently, their clogging. For some time, several types of refractory coatings, preventing the slag to fall into the hollows and reducing the external heat losses, have been tested. The refractory coatings, however, have several disadvantages: their specific profile, made of metallic structures coated by refractory castings anchored to them, require staff to work hard for the installation of the steel carpentry (cast steel plates welded to the pipe) and for the refractory coating (see Fig.

1).

Disclosure of the invention

The invention solves the above technical problems, being protecting modules for cooling piping hollows of industrial furnace, characterized by at least a couple of preformed elements, having the suitable profile to protect against the fall of slag. Said elements do not require long and complicated installation, and therefore reduce the assembling time. Moreover, another aim of the invention is to allow such elements to be disassembled and be reused during the furnace maintenance.

These and other advantages will be pointed out in the detailed description of the invention that will refer to the figures of the tables 1/3, 2/3 and 3/3 in which several preferred schemes of the invention are shown. All of them are examplifying and not restrictive.

Way of carrying out the invention

With reference to the above mentioned tables:

• Figure 1 is the schematic representation of the supporting pipe structure with the protection module installed, according to the state of art.

• Figure 2 shows the simple modifications which are needed to install the preformed elements according to the invention;

• Figures 3, 4 e 5 show three different embodiments of the protection modules and their details.

The lay-out shown in Fig. 1 comprises a standard supporting pipe (11), horizontal beams (12) and vertical struts (11), the hollows protecting modules (13) and its metal structure (14), according to the present state of art; the hollow to be protected by the slag is indicated with (15).

Aim of the invention is to realize such a protection by means of at least a couple of preformed elements, furnished with a steel horizontal structure, with suitable composition, and a plurality of stiffening steel structures. A very important component of the invention is the fast assembling system which assures the

sealing, by means of two or more steel pins, inserted in the internal pipes of the preformed elements. In this way, the work to be executed inside the furnace is much more reduced. Because, as shown in Fig. 2, it essentially relates to the assembly of a steel ring (9), welded to the movable piping (11); this ring serves as a support basis of the two preformed elements. Moreover, to maintain the working direction of the prefabricate, avoiding its rotation, two little steel pipes (3) are welded in a position, to result coaxial with the pipes inside the preformed elements; together they form a hinge in which the assembly pin (4) will be lodged.

According to the invention, said protecting modules (10) are realized by means of preformed elements (10') and (10"), having the right profile to protect the hollows against the slag fall. As already mentioned, said preformed elements only requires the installation (see Fig. 2) of a ring (9), preferably made of steel, welded to the movable pipe, which serves as a basis for the prefabricate, and of two little pipes (3), also preferably made of steel. Referring to Fig. 3, the two preformed elements (10') and (10"), once positioned on the ring (9), are fixed to the piping (11) by means of a hinge system (2) with fixing pins (4). The preformed elements are internally made of a metal structure, preferably a steel one, comprising of a collar (1), a plate (5) and a plurality of fixing means (6) to support the refractory coating. This one is made of refractory concrete (8), comprising a steel

needle-shaped matrix and an ecological ceramic fiber (7). Figs. 3, 4 and 5 show three different embodiments of said hollow protecting modules: in fact the prefabrication can be realized with symmetric halves, with longitudinal joint and three fixing pins (Fig. 3), or with two non-symmetric halves having a circular (Fig. 4) or a trapezoidal (Fig. 5) cross section, with transversal joint and two pins. The geometry of the protecting modules can be adjusted according to the type of hollow to be covered. The assembling time is remarkably reduced. Moreover, the invention allows the disassembly of said preformed elements, when the furnace is under maintenance, specially when the coatings under said elements need to be spot tested or removed; the invention also allows the reuse of the preformed elements.