Technical Field The present invention relates to a process and apparatus for compacting material used, in particular, in the ceramics industry.

Background Art Current processes for compacting material for the ceramics industry, for example, in the tile production sector, comprise various steps which allow the bonding of various components initially in the powder state, in order to arrive at the end product.

Such processes include a first step of atomising the material in order to obtain the powders, which contain a given percentage humidity, allowing subsequent compacting. The individual components of the ceramic material cannot be compacted and may be kept together at room temperature, thanks to the humidity in the relative bonding agent.

According to prior art, the moistened powders are subjected to pressing using high powered presses (in one or more steps), to obtain a compacted material containing a given percentage humidity.

The compacted material is then dried in order to eliminate the humidity and obtain a product which may subsequently be glazed and placed in a kiln to make, for example, the classic tile.

The process described, therefore, involves various steps which require the set up of a complex plant, consisting of machines and apparatus of different kinds.

In particular, the pressing step necessitates the use of machines which are very powerful and, as a result, very large.

Moreover, to obtain a high degree of compacting and, therefore, optimum strength and rigidity in the end product, various steps are required (pressing and subsequent drying), which means that production is time consuming.

The product obtained using the known process has a single thickness which cannot be varied along the longitudinal dimensions, since the pressing is performed by a single press which acts on the entire surface of the mould.

Disclosure of the Invention The aim of the present invention is, therefore, to overcome the above-mentioned disadvantages by providing a process and apparatus for compacting ceramic material which do not require the use of large presses.

Another aim of the present invention is to simplify the compacting process, in order to limit the time required and, at the same time, limit the use of different devices in order to obtain the end product.

Yet another aim of the present invention is to provide a process for obtaining a ceramic product, for example a tile, which is very strong and rigid, and which can be made with a longitudinal dimension of varying thickness.

These and other aims, which appear in the description below, are fulfilled in accordance with the present invention by a process for compacting material for the ceramics industry, comprising steps of

inserting the material in the form of powders into a container element; and pressing the powders in the container element, characterised in that the pressing step involves mechanical pressure combined with ultrasonic vibrations.

The present invention also relates to an apparatus for compacting material for the ceramics industry, comprising a container element for the material in the form of powders and means for compressing the powders, characterised in that the compression means comprise at least one presser and at least one source of ultrasonic vibrations which act upon the powders.

Short description of drawings Further technical features of the present invention and the advantages are more clearly described in the detailed description below, with reference to the accompanying drawings, which illustrate a preferred embodiment of the invention, without limiting the scope of its application, and in which: Figure 1 is a schematic view of an apparatus for performing the process for compacting material for the ceramics industry; Figure 2 is a schematic view of a second embodiment of the apparatus made according to the present invention.

Detailed description of the preferred embodiment of the invention In the accompanying drawings, the numeral 1 denotes an apparatus for compacting material used in the ceramics industry and made in accordance with the present invention.

The apparatus 1 comprises a container element 2, for example a mould, which holds the powders of the

material to be compacted and gives a specific shape to the product which is obtained by compacting.

The powders of ceramic material are inserted in the mould 2 by suitable feed means 3, consisting for example of a hopper 4, downstream of which there may be a device 5 for dosing the quantity of material to be inserted in the mould 2.

The apparatus 1 has powder compression means 6, driven by suitable drive means 7.

In the apparatus 1 disclosed, the compression means 6 comprise at least one presser 8 and a source 9 of ultrasonic vibrations.

Advantageously, in the embodiment illustrated in Figure 1, the presser 8 is connected to the source 9 of ultrasonic vibrations to constitute a sonotrode presser.

The sonotrode presser 8 and mould 2 are mobile between a non-operating position and an operating position, in which the presser makes contact with the powders to be compacted.

The apparatus 1 may also comprise a plurality of pressers 8 and at least one source 9 of ultrasonic vibrations which affect the entire surface of the container element 2.

Advantageously, the pressers 8 may be connected to a single source 9 or respective sources 9, so that each exerts pressure on the powders independently.

As illustrated in Figure 2, the number of sonotrode pressers 8 may vary according to the final dimensions of the compacted product. For example, in the case of a tile, there may be four pressers 8 arranged in such a way as to allow simultaneous compacting of the four quadrants of the tile.

This arrangement allows the even distribution of the pressure exerted on the surface of the tile, limiting the risk of uneven compacting which could lead to the formation of some zones which are more fragile.

The apparatus 1 may also comprise a support for the mould and handling means for the end product, which are not illustrated in the accompanying drawings.

The apparatus 1 allows the implementation of the process in accordance with the present invention, in which the pressing step is carried out using ultrasonic power.

The process includes a step of inserting the material, in the form of powders, into the mould 2, followed by the pressing step.

During the pressing step, the sonotrode presser 8 is brought into contact with the material in the mould 2, in such a way as to transmit the power of the ultrasonic vibrations to the material during the mechanical compression.

Advantageously, the process disclosed comprises a first step, during which a bonding agent containing a given percentage humidity is added to the powders.

The material is compacted by the action of the ultrasonic vibrations on the structure of the bonding agent added to the powders. The power transmitted to the mixture of powders and bonding agent in the form of ultrasonic vibrations causes the humidity content to be released and consequent cohesion of the bonding agent, allowing the material to be compacted.

The addition of a bonding agent allows the material to be compacted during the pressing step, thus eliminating the subsequent drying step.

The bonding agent may be a silicate in the liquid state, or another organic or inorganic additive able to modify its chemical-physical state following the release of humidity.

By means of the process disclosed, during the pressing step, compacting is achieved by a combined mechanical-thermal effect, thanks to the use of the sonotrode presser 8 which acts upon the mixture of powders and bonding agent, since the ultrasonic power

which passes through the material, making the water molecules vibrate, modifies the chemical-physical state of the material.

In the process disclosed, a single pressure applied by a high powered press is substituted with a set of lower pressures, eliminating the need to use large, expensive devices, which also consume a lot of power.

The addition of the bonding agent and the use of ultrasonic vibrations mean that the drying step, which increases the time required in order to obtain the end product, may be eliminated.

The compacting obtained using the process and apparatus disclosed allow the obtainment of a product which is very strong and rigid, since the components are joined together not only by mechanical compression, but also by transforming the molecular structure of the components themselves.

Moreover, the possibility of having a modular presser allows the compacting of products with a large surface area or different shapes, without necessitating the use of presses with different degrees of power or different shapes.

The apparatus equipped with a modular presser also allows different thicknesses along the longitudinal dimensions of the product.

The invention described can be subject to modifications and variations without thereby departing from the scope of the inventive concept. Moreover, all the details of the invention may be substituted by technically equivalent elements.