Field of the Invention More particularly, the present Invention refers to technical and functional improvements specially developed in equipment and process for the manufacture of ceramic tegula-type roof tile.

State of the Au As is known, there are currently innumerable types of roof tiles traditionally made of ceramic material, however, one of those types, known as tegula roof tile, due to its design, is notoriously made of concrete.

Even though the concrete tegula-type roof tiles are an excellent quality product, they require a different production process and care in the drying process, also requiring other care as a function of their large weight.

Accordingly, the ideal thing would be manufacturing said tile with ceramic material, because in this case the advantages inherent to the material would be associated to the type of tile.

Scope of the Invention Means to manufacture the tegula type roof tile with ceramic material, by extrusion or pressing and with this, as already said, associating the advantages of the material and the type of roof tile, among which are: a) an excellent thermal effect, thanks to the ceramic material, be it extruded or pressed; b) more weather resistance;

c) a better aesthetic appearance, not only due to the ceramic itself, but also because said material allows different types of finishes ; d) the ceramic material, due to its somewhat"plastic"consistence, provides a process with a substantially reduced cost, is cleaner and does not harm Nature ; e) the tegtda roof tile obtained with the present process, due to its lighter weight, allows a decrease in the material and cost of roof structures (frames) in general and f) presents a substantially lower water absorption rate in relation to concrete roof tiles.

Description of drawings For a better understanding of the present Invention ; a detailed description thereof is made below with reference to the annexed drawings, wherein: FIGURE 1 is a perspective view of two tegula-type roof tiles, one made of concrete (tile on the left) and the other, made of ceramic material (tile on the right)-which is the subject matter of the present invention ; FIGURE 2 are views of the vacuum extruder ; FIGURE 3 illustrates a perspective view of the mold employed at the outlet of said extruder ; FIGURE 4 is a perspective, view showing the cannon (spiral) of the extruder; FIGURE 5 is a view of the extruder's outlet; FIGURE 6 through 10 are views of the automatic and manual cutting systems ; FIGURE 11 is a perspective view of the wagon; FIGURE 12 is a perspective view of the enameling equipment ; FIGURE 13 is a perspective view of another wagon.

Detailed description of the invention According to these illustrations and the details thereof, more particularly Figure 1, the present Invention, TEGULA-TYPE ROOF TILE is characterized in that it is molded of ceramic material employing appropriate ratios of plastic clays, argilites and ivory palm.

The PROCESS FOR MANUFACTURE OF TEGULA-TYPE ROOF TILE comprises the following steps: a) selection of the raw material, which corresponds to a combination of plastic clays, argilites and ivory palm, in a proportion of 33% of each ; b) the mixture of components is homogenized; c) the homogenized mixture goes through a drying stage in a rotating dryer at an approximate temperature of 800°C to remove the moisture; d) the homogenized and dry mixture is crushed to a fine particulate size in impact and peadular mills, is then sieved, completing the preparation of raw material, which is kept in storage silos. e) extrusion molding-the homogenized mixture is withdrawn from the silos and goes to a humidifying system in order to obtain a uniform moisture content of around 18% water, in order to make a substantially plastic dough ; f) The, humidified dough is taken by conveyor belts to a vacuum extruder (figures 2a and 2b), the outlet of which is equipped with an improved mold (figure 3), wherein the roof tile extrusion molding takes place as illustrated on figure 1 ; also in this stage the plastic mixture or dough is pressed towards the extruder outlet, through a spiral system (figure 4) and the air entrained between the mixture particles is removed by a vacuum pump, in order to turn it into a compact dough ; in addition, the compact, extruded dough on moving towards the extruder outlet is submitted to a stress relief (caused by the spirals'pressure), so that said dough can be uniformly extruded in order to provide the final roof tile shape ;

g) after leaving the extruder (figure 5), the roof tile exits in the shape of a continuous strand or profile which is in turn transversely cut by an automatic or manual cutting unit (figures 6 through 10), so that the units can be separated and, afterwards, the fittings are automatically made, completing the configuration of the tegula-type roof tiles which are then placed on wagons (figure 11) with shelves, so that the roof tiles can be taken to continuous dryers at a temperature of 130] °C in order to remove the existing residual moisture, h) after the drying stage, the roof tiles can be taken directly to the oven for burning (wherein the natural, non-enameled roof tile is obtained), or go through a ceramic enamel application process for subsequent burning, in a sole, single-burn process, wherein the enameled roof tile is obtained ; i) the enameling stage is done through application of a liquid (enamel) on the roof tile, in a so-called veil or disk (blade) process (figure 12); j) The burn stage is done in a tunnel (or roller) oven, wherein they are placed on wagons and piled with the aid of refractory supports (figure 13), so that after the roof tiles are enameled they may go through a single-burn stage, made at temperature of about MOO°C ; and k) classification and packaging-after the burn the roof tiles are removed from the wagons and go through a selection stage, wherein the parts that have suffered some kind of defect during the process are removed and, afterwards, they are grouped in bales or packages and to the finished product storage, from which they will be subsequently shipped on trucks for marketing.

In a variation of the process, the extrusion molding can be. replaced by pressing and, in this case, the homogenized mixture is withdrawn from the silos and goes to a humidifying system in order to obtain a unicorm nibaure, content of about 18% water and afterwards, this mixture is taken through conveyor belts to the extruder, wherein the latter will give it the shape of a cylindrical bar through a mold provided at the outlet thereof This cylindrical bar is cut to pieces (having the volume of one roof tile mass) and taken to a press which, through molds provided thereon, will press these bars to shape a roof tile which is in turn processed in the same manner as previously described.

Referring to figure 3, the extrusion mold was improved with a stress relief system (A) positioned inside the intermediate cannon of the tile making machine (M) for the purpose of relieving the stresses caused by the extrusion force applied by the pressing spirals (C).