Field of the invention

The invention relates to a ceramic item, generally adapted for use to quickly cover surfaces, such as building walls, ventilated walls, floors and the like.

Background art

Ceramic items are known in the art, which consists of plates and are used to cover the surfaces of building rooms, such as floors and walls.

Typically, the items are in the form of ceramic tiles or plates and have standard sizes and perimeters, for easy handling by layers, and also for fitting the perimeters of the surfaces to be covered.

Particularly, currently manufactured rectangular items have sizes ranging from a few centimeters to a few tens of centimeters, and thicknesses ranging from a few millimeters to about twelve millimeters according to the material that forms them.

Also the side-length ratio is typically standardized, and typically includes ratios of not only 1 :1 , but also 2:1 , 3:1 and more, provided that one of the sides is an exact multiple or submultiple of the other side.

This side ratio condition is maintained to avoid the need of providing a plurality of molds for the presses that are used to form the items, i.e. the tiles and the plates, each mold having a different size to specially form items having different sizes.

In a prior art technique, ceramic items of different sizes may be obtained without using molds, i.e. by drawing, i.e. by creating a ceramic body web in a plastic state, which may be extruded by a drawing machine and cut transverse to the drawing direction, at predetermined lengths, while maintaining a fixed or substantially fixed transverse dimension of the web, and hence of the final item.

Nevertheless, the items obtained by drawing were affected by flatness problems during firing, especially in case of large overall dimensions, the latter being intended as sides as long as 50 centimeters or more, and this requires an additional surface smoothing step on the items after firing to restore flatness.

This prior art suffers from certain drawbacks.

A first drawback is that the ceramic items, i.e. the tiles and plates that are currently available on the market to cover large-size walls and floors, require time-consuming operations because a large number of standard items must be used and arranged in side-by-side relationship, whereby a correspondingly large number of finishing operations must be carried out, as is required when laying ceramic tiling, such as filling the joints defined between the various items arranged side by side.

A second drawback of the prior art is that, once the prior art items are laid upon the surface to be covered, some planar misalignment often exists between them, and creates projections between contiguous sides which may cause practical problems, i.e. stumbling on floors, and aesthetical problems, i.e. show poor laying accuracy in floors and walls, and an immediately perceivable optical defect, that affects the value of both the individual items and the overall tiling.

A further drawback of the prior art is that, when covering surfaces, especially large surfaces, items, i.e. tiles and plates, having standard but different sizes must be juxtaposed, while maintaining side alignment, to reproduce the expected two-dimensional laying patterns.

Therefore, the items shall have sizes that are multiples or submultiples of one another.

Disclosure of the invention

One object of the present invention is to improve the state of the prior art.

Another object of the invention is to provide a ceramic item that affords quick covering of surfaces, even those having a large size, thereby reducing working times and labor costs.

A further object of the invention is to provide a ceramic item that can form tilings with no apparent planar and alignment defect between items.

A further object of the invention is to provide a ceramic item that can be laid using the typical laying technique known to those skilled in the art. Yet another object of the invention is to provide a ceramic item that can be juxtaposed to other known items having standard sizes, while maintaining alignment between its sides and those of the juxtaposed standard items, thereby forming patterned tilings with no misalignment between the sides of the composing items.

In one aspect the invention relates to a ceramic item as defined by the features of claim 1 .

In another aspect the invention relates to a molding method for making a ceramic item, as defined by the features of claim 8.

In yet another aspect the invention relates to a cooling apparatus for cooling a ceramic item, as defined by the features of claim 1 3.

The invention affords the following advantages:

- quickly covering surfaces, possibly of large sizes, thereby considerably reducing laying and finishing times and hence labor costs;

- providing tiling arrangements that exhibit no apparent surface misalignment between juxtaposed items;

- providing tilings composed of one or more items of the invention, in combination with juxtaposed prior art standard-sized items, to provide a generally high-value architectural effect.

Brief description of the drawings

Further characteristics and advantages of the invention will be more apparent from the detailed description of a preferred, non-exclusive embodiment of a ceramic item, which is shown as non-limiting example in the annexed drawings, in which:

FIG. 1 is a perspective view of a ceramic item of the invention;

FIG. 2 is a schematic perspective view of a ceramic item of the invention interposed between prior art standard-sized items;

FIG. 3 is a highly schematic view of a cooling apparatus that is used for cooling a ceramic item of the invention, after the firing step.

Detailed description of a preferred embodiment

Referring to the figure, the ceramic item 1 has a surface area "A" which, in the illustrated embodiment, is bounded by a rectangular perimeter that defines a long side 2 and a short side 3.

The skilled person will understand that the sides 2 and 3 may also not be straight, and that the perimeter may also have other geometric shapes, if so requested by laying requirements.

The item 1 has a thickness "S1 ".

In the preferred embodiment, the ceramic item 1 has, in combination, a long side 2 with a greater length of 1 ,797 millimeters, a short side 3 with a smaller length of 797 millimeters and a thickness of 1 0 millimeters.

Therefore, one or more items 1 of the invention may be used to cover large surfaces, in a much shorter time than with prior art standard items, thereby affording advantageous savings in terms of times and labor costs.

Furthermore, since a considerably smaller number of items is required to cover a surface of predetermined size, then the number of joints between the juxtaposed sides of the items 1 of the invention is also reduced.

This will considerably reduce the risk of misalignment between contiguous sides, and will provide a tiling arrangement having a regular and flat surface, with no steps or misalignments between contiguous items.

The ceramic item 1 is obtained by a method that includes a series of successive steps.

Typically, a first step of the method is the selection of the clays to be used for filling the mold of a press of proper size, choosing a particular particle size that is preferably obtained by selecting clays through screening with a predetermined number of sieves.

More in detail, at least six screening sieves are used, each having different mesh sizes.

More in detail, the optimal particle size of the composing clays is obtained from clays having the following screening residue amounts:

0.250 27.4

0.1 50 1 7.5

0.075 8.6

With the method of the invention, the moisture of the clays is also required to be controlled within a range from 4.5% to 5.5%.

When the mold of the press (not shown in detail and known to the skilled person) is entirely filled with the selected clays (or clay mixture), the punch acts to press them in the mold with a pressure of 480 Kg/cm ² , thereby creating a ceramic item 1 in the raw state.

Then, this item is removed from the mold and conveyed to the next firing step for final stabilization, in a firing kiln at a temperature of about 1220/1 225 °C for a time of 1 .5 hours.

At the end of the firing step, the fired ceramic item 1 undergoes a cooling step, by being conveyed through a cooling apparatus 1 0 having a live roller bed conveyor (see Figure 3) with hollow rollers 1 1 .

As shown in Figure 3, all the rollers 1 1 have a free end 1 1 A with apertures 1 2 formed therein and an opposite end 1 1 B, also free, which is designed to receive the end 1 3 of a respective suction pipe 14, which is connected to a conventional suction apparatus 1 5.

The cooling apparatus 1 0 is also equipped with a blowing unit 1 6, which is designed to blow cooling airflows "F1 " on the surface area "A" of the item 1 .

During the cooling step, the ceramic item 1 has cooling airflows "F1 " impinging upon it from above, whereas the bottom surface area, referenced "B", is cooled by contact with the outer surface of the rollers 1 1 , which is in turn kept cold by means of additional cooling airflows "F2", which is sucked into each roller 1 1 through the pipe 14 and the action of the suction apparatus 1 5.

Thus, in spite of the large size of the ceramic item 1 and its thickness "S1 ", cooling occurs evenly throughout the thickness "S1 " both from above and from below, which will prevent the occurrence of internal tension that might affect flatness.

The ceramic item 1 may be decorated using technologies known to the skilled person, and not described herein in detail.

The invention was found to fulfill the intended objects.

The invention so conceived is susceptible to a number of changes and variants within the inventive concept.

Furthermore, all the details may be replaced by other technically equivalent parts.

In practice, any materials may be used as needed, without departure from the scope of the following claims.