IT202000013594A1 - PLANT AND METHOD FOR THE REALIZATION OF CERAMIC ITEMS - Google Patents

Description

DESCRIPTION

of the patent for industrial invention entitled:

?PLANT AND METHOD FOR THE REALIZATION OF CERAMIC ITEMS?

TECHNICAL FIELD

The present invention ? relating to a plant and a method for the production of ceramic articles.

BACKGROUND OF THE INVENTION

In the field of the production of ceramic articles (in particular, slabs; more specifically, tiles) ? the use of machines for the compaction of semi-dry powders (ceramic powders; humidity content around 5-6%) is known. These machines include ceramic powder feed devices of different types.

Often these machines are used to make products that imitate natural stones, such as marble and/or granite. These products have internal veins randomly distributed within the thickness of the products.

Alternatively or an addition pu? it may be advisable to use powders of different types to obtain articles with particular structural and/or physical characteristics.

In some cases, mixtures of powders of different colors are brought in a random distribution within cavities. of steel molds and then compressed in order to obtain, for example, slabs of compacted powder.

? It has been proposed to produce slabs with random distribution of powders of different colors also using continuous compacting machines which include a conveyor group for transporting (substantially continuously) the powdered material along a determined path through a work station, at which ? placed a compacting device, which ? adapted, by means of the cooperation of pressure rollers, to compact the material in powder form so as to obtain a layer of compacted powder.

An example of a continuous machine for compacting ceramic powder? described in the international patent application with publication number WO2005/068146 by the same applicant as the present application.

? It is also known to produce (for example by digital printing) a graphic decoration over the layer of compacted ceramic powder so as to make the finished article visually smoother. similar to a natural product.

The systems available so far for the compaction of ceramic powders of different types have, however,? several drawbacks. Among these we mention the following. The distribution of the powders occurs randomly and therefore intrinsically cannot be reproduced. Very rarely the veins that are created in the thickness of the articles (and therefore visible by looking at the edge of the articles themselves) are in a coordinated position with respect to the surface decorations obtained by printing.

The aesthetics of the product are significantly affected, making it much more? the non-similarity with respect to a natural product (for example marble) is evident.

In some cases ? it was possible to improve the synchronization between the surface decoration and the grain existing inside the ceramic body, obtained with colored powders by exploiting some particularly innovative devices (see, for example, the patent applications EP1787779A2, WO2018163124A1 and EP3424661A1 by the same applicant). Note for? that a very ?widespread? trend of the vein in the mass is often obtained? (ie with a median directrix at a small angle to the horizontal plane) which is not always sufficiently ?natural? (see e.g. figure 12).

The veins of natural materials (see for example Figure 13) are also more? chromatically rich and not endowed (contrary to what often happens with state-of-the-art ceramic materials) with relatively large single-color areas that stand out in an anomalous way to the eye of the observer.

Purpose of the present invention? that of providing a plant and a method which allow the drawbacks of the known art to be overcome, at least partially, and which are, at the same time, easy and cheap to produce.

SUMMARY

According to the present invention there is provided a plant and a method for making ceramic articles according to what is stated in the independent claims that follow and, preferably, in any one of the claims depending directly or indirectly on the independent claims.

BRIEF DESCRIPTION OF THE FIGURES

The invention is described hereinafter with reference to the attached drawings, which illustrate some non-limiting embodiments, in which:

- figure 1 ? side and schematic view of a plant in accordance with the present invention;

- figure 2 ? a front and schematic view of a detail of the machine 1 during operation;

- figure 3 ? a front and schematic view of a different embodiment of the detail of figure 2 during operation;

- figure 4 ? a front and schematic view of a different embodiment of the detail of figure 2 during operation;

- figure 5 ? a front and schematic view of the detail of figure 4 with the addition of some details during operation;

- figure 6 illustrates, for comparative purposes, the behavior of a powder with a low angle of repose;

- figure 7 ? a schematic plan view of a portion of the system of Figure 1 during operation;

- figures from 8 to 11 are front views of successive work phases;

- figure 12 ? a photograph of a ceramic article obtained using a state-of-the-art machine;

- figure 13 ? a photograph of a natural marble slab;

- figure 14 ? a schematic plan view of a different embodiment of the portion of the system of FIG. 7 during operation;

- figure 15 ? a front and schematic view of the detail of figure 5 in the embodiment of figure 14;

- figures 16 to 18 are schematic and plan views of a different embodiment of the detail of figure 5 in successive work phases;

- figure 19 ? a side and schematic view of a part of the system of figure 14 including the detail of figure 15;

- figure 20 ? a schematic plan view of a different embodiment of the portion of the system of FIG. 14 during operation;

- figure 21 ? a front and schematic view of the detail of figure 5 in the embodiment of figure 20;

- figure 22 ? a side and schematic view of a part of the system of figure 20 including the detail of figure 21;

- figure 23 ? a schematic plan view of a different embodiment of the portion of the system of FIG. 20 during operation;

- figure 24 ? a front and schematic view of the detail of figure 5 in the embodiment of figure 23;

- figure 25 ? a side and schematic view of a part of the system of figure 23 including the detail of figure 24;

- figure 26 ? a schematic plan view of a different embodiment of the portion of the system of FIG. 23 during operation;

- figure 27 ? a front and schematic view of the detail of figure 5 in the embodiment of figure 26;

- figure 28 ? a side and schematic view of a part of the system of figure 26 including the detail of figure 27;

- figure 29 ? a schematic plan view of a different embodiment of the portion of the system of FIG. 26 during operation;

- figure 30 ? a front and schematic view of the detail of figure 5 in the embodiment of figure 29;

- figure 31 ? a side and schematic view of a part of the system of figure 29 including the detail of figure 30;

- figure 32 ? a schematic plan view of a different embodiment of the portion of the system of FIG. 29 during operation;

- figure 33 ? a front and schematic view of the detail of figure 5 in the embodiment of figure 32;

- figure 34 ? a side and schematic view of a part of the system of figure 32 including the detail of figure 33;

- figure 35 ? a schematic plan view of a different embodiment of the portion of the system of FIG. 29 during operation; And

- figure 36 is a schematic plan view of the plant of figure 35 in a different operating configuration.

DETAILED DESCRIPTION

In accordance with a first aspect of the present invention, in figure 1, with 1 ? indicated as a whole a plant for the production of ceramic articles T. Plant 1 ? equipped with a compacting machine 2 to compact some CP powder material, including ceramic powder (in particular, the CP powder material is ceramic powder; more specifically, the ceramic powder has a moisture content of 5-6% about).

In particular, the ceramic articles T produced are slabs (more precisely, tiles).

The machine 2 comprises a compacting device 3, which ? disposed at a workstation 4 and ? adapted to (configured to) compact the powder material CP so as to obtain a layer of compacted powder KP; and a conveyor unit 5 (configured) to transport (in a substantially continuous manner) the powdered material CP along a section PA of a path determined from an inlet station 6 to the work station 4 (in particular, in a forward direction A ) and the layer of compacted powder KP from the work station 4 along a section PB of the route determined to an outlet station 7 (in particular, in direction A). In particular, the path determined ? made up of sections PA and PB.

According to non-limiting embodiments, the compacting device 3 is configured to exert a pressure of at least about 350 kg/cm<2> (in particular, at least about 380 kg/cm<2>; in particular, up to about 450 kg/cm<2>; more specifically, up to about 420 kg/cm<2>) on the CP powder material.

Machine 2? also equipped with a power supply group 8, which ? configured to feed the powdered material CP to the conveyor unit 5, in particular at the inlet station 6 (more specifically, in an area CZ of the conveyor unit 5).

The power unit 8 comprises a power supply device 9 (see, in particular, figures 1 and 7), which ? configured to feed a first powder FP to (directly in contact with) a first part (of area CZ) of the conveyor unit 5 (in particular, directly in contact with the conveyor unit 5) so that the first powder FP substantially has a first thickness (of height H) on the conveyor unit 5 (see, in particular, figures 3 and 5). In particular, the feeding device 9 ? configured to feed the first powder FP to the conveyor group 5 so as to place it on the first part (of the CZ area) of the conveyor group 5.

Pi? precisely but not necessarily, the power supply device 9 ? arranged along the PA section. even more precisely, the power supply device 9 ? arranged at the entrance station 6.

The powder material CP comprises (in some non-limiting cases, consists of) the first powder FP.

Advantageously but not necessarily, the feed device 9 is configured to feed the first powder FP that ? (mainly; in particular, for at least about 70%; more particularly, for at least about 85%; even more particularly, for at least about 95% by weight with respect to the total weight of the first FP powder) consisting by particles having dimensions smaller than about 180 ?m (in particular, greater than about 30 ?m) and, in particular, having an angle of repose greater than about 55?, in particular greater than about 65?, more especially above about 80? (more specifically, less than about 90?).

The dimensions are obtained by successive screenings with sieves with holes of decreasing dimensions (diameters). The diameter of the holes in the first sieve that does not allow the particles to pass indicates the size (i.e. diameter) of the particles.

Measurements by successive screenings are carried out as long as the dimensions (i.e. diameters) of the particles and sieve holes permit (in particular, down to a minimum of 0.05 mm). Below these sizes (specifically, 0.05mm), particle size is measured as the mean diameter D(v,0.5) measured by a laser particle sizer - specifically, using a Mastersizer Microplus Ver.2.19 laser particle sizer (Malvern Instruments <?>Ltd). In particular, the measurements of the mean diameter are carried out in accordance with the ISO 13320:2009 standard.

Advantageously but not necessarily, the feed unit 8 comprises a feed device 10, which ? configured to feed a second powder SP (predominantly by weight; in particular, at least about 70%; more particularly, at least about 85%; even more particularly, at least about 95% by weight of to the total weight of the second powder SP) consisting of particles having dimensions greater than about 200 ?m (in particular less than about 600 ?m) on (directly in contact with) a second part different from said first part (of the CZ area) of the conveyor group 5. In particular, the second powder SP has an angle of repose lower than about 50?, more? especially lower than about 45? (specifically, higher than about 20?).

Pi? precisely but not necessarily, the power supply device 10 ? configured to feed the second powder SP to the conveyor group 5 so as to place it on the second part (of the zone CZ) of the conveyor group 5.

The angles of repose are understood to be measured according to the provisions of the ASTM C1444-00 standard. The comparison between figures 6 and 3 (and between figures 2 and 4) shows the different behavior of PP and PPP atomized powders at low repose angle (figures 6 and 2) and the first FP powder (micronized), which, advantageously but not limited to it, it has a high angle of repose.

The CP powder material includes the second SP powder and the first FP powder. Pi? precisely but not necessarily, the CP powder material ? consisting of the first powder FP and the second powder SP.

Advantageously but not necessarily, the plant 1 (more precisely, the machine 2) comprises a compression device 11 (figures 1, 7 and 8), which is arranged at a compression station 11* (in particular, along the first section PA; more particularly at the inlet station 6) upstream (in the direction A) of the work station 4 and downstream (in the direction A) of the feeding device 9 and ? adapted to (configured to) compress the first FP powder so that the first FP powder has a second thickness lower than the aforementioned first thickness.

Yes ? experimentally observed that thanks to the combination of the feeding device 9, the compression device 11 and the compacting device 3 ? It is possible to obtain an improved handling and compaction of the powder material (in particular, of the first powder FP). In this regard, it should be noted that the powder material (which already tends, being micronized - see above and compare figures 6 and 2, to remain in position) is initially partially compressed so that the position of the different particles remains even more? fixed. Furthermore, the use of the compression device 11 and of the compaction device 3 (in other words, the fact that the compaction takes place in two successive phases) allows to obtain a more compacting. homogeneous and, therefore, ceramic articles T with reduced internal stresses. What? by doing this, the action of compaction and therefore of evacuation of the air present between the grains of dust is divided into two distinct phases. This deaeration? very important for good compaction of the ceramic mass.

Yes ? also experimentally observed that thanks to the combination of the feed devices 9 and 10 and the compression device 11 it is surprisingly possible to obtain compacted powder KP and ceramic articles T which have well-defined areas containing the first powder FP and, at the same time, excellent resistance ( low internal tensions).

According to some non-limiting embodiments, the compression device 11 comprises (?) a transversal roller (in particular, substantially perpendicular) to the direction A. In particular (figure 8), this roller ? spaced from the conveyor unit 5 by a height HH.

Pi? precisely but not necessarily, the power supply device 9 ? configured to feed the second powder SP to the conveyor unit 5 so that the second powder SP has a third thickness on the conveyor unit 5. The third thickness? lower than the first thickness and, in particular, ? substantially equal to the second thickness (and corresponds to the height HH).

In particular (figures 1 and 11), it should be noted that the compacting device 3 is configured to compress the powder material CP (which, more specifically, is fed to the compacting device 3 with a thickness substantially equal to the second thickness ? and to the third thickness, substantially corresponding to the height HH) so that the layer of powder compacted KP present a fourth thickness (corresponding ? equal - to a height HHH), lower than the second (and third) thickness (and therefore to the height HH).

Advantageously but not necessarily, the heights H, HH and HHH are selected so that the density? of the layer of compacted powder KP is substantially homogeneous.

Pi? in particular, the first thickness, the second thickness (therefore also the third thickness) and the fourth thickness (and therefore the heights H, HH and HHH) are selected so that the following relationship is satisfied:

D1 = D2 ? 0,030 Kg/dm<3 >(preferably but not necessarily, D1 = D2 ? 0,020 Kg/dm<3>)

in which

D1 = HH/HHH x SD

D2 = H/HHH x DF

in which DS ? the density? apparent of the second powder SP; DF ? the density? apparent of the first FP powder.

Advantageously but not necessarily (figures 1 and 7), the feed device 9 is arranged upstream (in the forward direction (A)) of the feed device 10; the compression device 11 ? arranged along the section PA between the feed device 9 and the feed device 10.

According to some non-limiting and not illustrated embodiments, the feed device 9 is arranged downstream (in the forward direction (A)) of the feed device 10; the compression device 11 ? arranged along the section PA downstream of the feed device 9.

Advantageously but not necessarily, the feed device 9 (figures 2, 4 and 5) comprises at least two units side discharge 12 and at least one?unit? of central unloading 13, which ? configured to bring (arrange) a first part FFP of the first powder FP on the conveyor group 5. Each unit? side discharge 12 ? configured to arrange (carry) a respective second SFP part of the first powder FP to the sides and in contact with the first FFP part of the first powder FP so that the second SFP parts of the first powder FP laterally support and limit the movements of the first FFP part of the first powder FP.

In this way a positioning of the first FFP part is obtained (compare figure 2 with figure 6 ? relating to PP and PPP atomized powders with relatively low angle of repose, and figure 4 with figure 3 ? relating to the first FP powder with a relatively high angle of rest) even more? accurate and stable.

In particular, the unit? central exhaust 13 ? disposed between the said at least two units? side discharge 12.

Advantageously but not necessarily, the unit? central discharge outlet 13 has an outlet mouth 14 facing the conveyor unit 5 (in particular, downwards) and spaced from the conveyor unit 5 by a height H substantially equal to the first thickness. In particular, also each unit? side discharge 12 has a respective outlet 15 facing the conveyor unit 5 (downwards) and spaced from the conveyor unit 5 by a height H substantially equal to the gi? mentioned first thickness.

According to some non-limiting embodiments, the units? side discharge 12 and the unit? discharge pipes 13 are (substantially integral with each other and d) aligned in an alignment direction B. Pi? in particular, the direction B ? transverse to the A direction.

Advantageously but not necessarily, the power unit 8 (more precisely, the power device 9) comprises a unit? of rotation 16 which ? configured to rotate the unit? side discharge 12 and the unit? discharge unit 13 (so as to change the orientation of the relative position of the lateral discharge units 12 and of the central discharge unit 13).

In this way ? It is possible to modify (or keep unchanged) the width of the first powder FP on the conveyor unit 5.

Pi? precisely, but not necessarily, the unit? of rotation 16 ? configured to rotate the unit? side discharge 12 and the unit? central discharge tube 13 so as to modify the alignment direction B. In particular, the alignment direction B ? transverse to the A direction.

In particular, the unit? of rotation 16 ? configured to rotate the unit? side discharge 12 and the unit? central discharge 13 about an axis AA substantially perpendicular to the advancement direction A. Pi? in particular, the axis AA ? substantially perpendicular to a conveying plane of the conveying unit 5, on which conveying plane lies the first powder FP, while, in use, it is fed to the feeding device 10. For example, the unit? of handling pu? include an electric motor configured to act on a shaft integral with the unit? side discharge 12 and to? unit? central drain 13.

It should be noted that, in particular, in use, the first powder FP (and possibly also the second powder SP) lies on the aforementioned conveying plane of the conveyor unit 5, while it is fed (along the section PA) towards the outlet station 7 ( to the compacting device 3).

Advantageously but not necessarily (figures 5 and 7), the power unit 8 comprises a unit? of handling 17, which ? adapted to move the feed device 9 (in particular, in a direction C transversal to the feed direction A) so that the first feed device 9 can achieve a distribution (in particular, of a given shape) of the first powder FP on the conveyor unit 5, in particular on the aforementioned conveying plane.

The combination of the unit? handling 17 and the unit? of rotation 16 ? particularly effective. In this way ? in fact, it is possible to create different distributions by also adjusting the width of the lines of the first powder FP (and/or of its first part FFP).

For example, the unit? handling 17 pu? include a raised guide (with respect to the conveyor unit 5), which extends in the direction C and on which the units are slidably mounted? side discharge 12 and the unit? central drain 13.

Advantageously but not necessarily (figure 1), the plant 1 comprises a printing device 18, which is configured to create a graphic decoration over the layer of compacted ceramic powder KP at a printing station 19 along the determined path (in particular along the section PB) downstream of the workstation 4. In particular, the decoration graphics ? coordinated with the distribution of the first powder FP.

According to some non-limiting embodiments, the plant 1 also comprises a unit? control 20, within which ? memorized a reference distribution and ? configured to control the feed unit 8 (in particular, together with the conveyor unit 5) so that the feed device 9 carries out the aforementioned distribution (of a determined shape) of the first powder FP on the conveyor unit 5 on the basis of the reference distribution ( in particular, in order to substantially reproduce the reference distribution). In particular, the unit? of control 20 ? configured to command the printing device 19 to carry out the graphic decoration on the basis of the reference distribution.

Advantageously but not necessarily, the plant 1 comprises a determination unit 21 (in particular, comprising an optical detector), which ? configured to detect (and determine) said distribution (of determined shape) of the first powder FP on the conveyor unit 5. In these cases, in particular, the unit? of control 20 ? configured to control the printing device 19 to create the graphic decoration on the basis of the reference distribution and as a function of what is detected by the determination unit 21, plus? in particular in function of one or more? differences between the reference distribution and said distribution (of a given shape) of the first powder on the conveyor unit (adapting? deforming? the graphic decoration).

In particular, the feeding device 9 ? located at a feed station 22 (along the section PA) and the feed device 10 ? located at a respective feed station 23 (along the section PA). The feed stations 22 and 23 are part of the input station 6. According to some non-limiting embodiments, the feed station 22 is arranged along the section PA upstream (in direction A) of the supply station 23.

According to some non-limiting embodiments (figures 1, 7 and 9), the feed device 10 comprises a containment chamber 24 (eg a hopper), which is configured to contain the second powder SP and to transfer the second powder SP to the conveyor unit 5 at the feed station 23. In particular, the containment chamber 24 has an outlet mouth 25 (figure 9), which is configured to pass the second powder SP and ? facing the conveyor unit 5 (downwards).

Pi? precisely but not necessarily, the outlet mouth 25 ? spaced from the conveyor unit 5 by the height HH substantially equal to the third thickness.

Advantageously but not necessarily, the outlet of the containment chamber 25 24 has an extension perpendicular to the determined path (more precisely to the direction A) greater than the sum of the extensions perpendicular to the determined path (more precisely to the direction A) of the outlet mouths 14 and 15 of?unit? of central unloading 13 and of the unit? side discharge 12.

Advantageously but not necessarily (figure 1), the implant 1 comprises a removal device 26, which is configured to remove a surface portion of the powder material CP arranged on the conveyor unit at a removal station 27 arranged downstream (with respect to the direction of advancement A), in particular along the first section PA, of the feed unit 8.

In this way ? at least partially possible to reduce any surface mixing between the first powder FP and the second powder SP. These advantages are particularly useful when the device 10 has a containment chamber 24 and an outlet mouth 25 (as described above). In these cases, the second powder SP present in the containment chamber 24 arranged in correspondence with the first powder FP substantially does not pass through the outlet mouth 25 but comes into contact with the first powder. It is, therefore, possible that some particles from the second powder SP pass through and/or, by contact, cause a displacement of the first powder FP. The second powder SP arranged correspondingly in the part of the conveyor unit 5 is not already? occupied by the first powder FP passes through the outlet mouth 25 and reaches the conveyor unit 5 (in particular, depositing itself on the aforementioned conveyor plane).

In particular, the remover 26 ? configured to remove a surface portion of the powder material CP by suction.

Advantageously but not necessarily, the plant 1 comprises a further application group 28 for at least partially covering the (one layer of) powder material CP with a layer of a further powder material. In particular, the application group 28 ? arranged along the determined path (more precisely along the section PA) upstream of the work station 4 (and upstream of the printing station 19). Thanks to the application unit 28, a (thin) layer of neutral color is obtained, on which the molding operations (following compaction) lead to higher quality results.

In particular, the machine 1 also comprises a cutting unit 29 for transversally cutting (in particular, in the direction A) the compacted ceramic powder layer KP so as to obtain slabs 30, each of which has a portion of the ceramic powder layer compacted KP. Pi? in particular, the cutting group 29 ? arranged along the section PB of the determined path (between the working station 4 and the printing station 19). The slabs 30 comprise (consist of) compacted ceramic powder KP.

Advantageously but not necessarily, the cutting unit 29 comprises at least one cutting blade 31, which ? designed to come into contact with the layer of compacted ceramic powder KP to cut it transversally.

According to some non-limiting embodiments, the cutting assembly 29 also comprises at least two further blades 32, which are arranged on opposite sides of the portion PB and are configured to cut the layer of compacted ceramic powder KP and define the lateral edges of the slabs 30 (and substantially parallel to direction A) ? possibly by dividing each plate 30 into two or more? longitudinal portions. In some specific cases, the cutting unit 29 ? such as that described in the patent application with publication number EP1415780.

In particular, the plant 1 comprises at least one firing oven 33 for sintering the layer of compacted powder KP of the slabs 30 so as to obtain the ceramic articles T. Pi? in particular, the cooking oven 33 ? arranged along the determined path (more precisely along the section PB) downstream of the printing station 19 (and upstream of the exit station 7).

According to some non-limiting embodiments, the plant 1 also comprises a dryer (known per se and not shown) arranged along the section PB downstream of the work station 4 and upstream of the printing station 19.

According to some non-limiting embodiments, the conveyor unit 5 comprises a conveyor belt 34 extending (and able to move) from the infeed station 6 and through the work station 4, along the (more precisely - at least - part of the) specified path.

According to some advantageous but non-limiting embodiments, the power supply unit 8 ? configured to bring a layer of powder material CP (uncompacted) to (on; and, in particular, directly in contact with) the conveyor belt 34 (at the entry station 6). In these cases, more precisely, the power supply device 9 ? configured to bring the first powder FP (uncompacted) to (on; and, in particular, directly in contact with) the conveyor belt 34 (at the feed station 22); in addition or alternatively, the power supply device 10 ? configured to bring the second (uncompacted) powder SP to (on; and, in particular, directly in contact with) the conveyor belt 34 (at the feed station 23).

In particular, the compacting device 3 ? adapted to (configured to) exert on the layer of ceramic powder CP (comprising the first powder FP and the second powder SP) a transversal pressure (in particular, perpendicular) to the surface of the conveyor belt 34.

According to some non-limiting embodiments, downstream of the belt 34 ? provided a succession of transport rollers.

According to some non-limiting embodiments, the compacting device 3 comprises at least two compression rollers 35 arranged on opposite sides of (one above and one below) the conveyor belt 34 to exert pressure on the powder material CP so as to compact the powder material CP itself (and obtain the compacted powder layer KP).

Bench? in figure 1 only two rollers 35 are shown, in accordance with some variants, ? is it also possible to provide for a plurality? of rollers 35 arranged above and below the conveyor belt 34, as described for example in the patent EP1641607B1, from which further details of the compacting device 3 can be deduced.

Advantageously (as in the embodiment illustrated in figure 1) but not necessarily, the compacting device 3 comprises a pressure belt 36, which converges towards the conveyor belt 34 in the forward direction A. In this way, a pressure (from top to bottom) which gradually increases in direction A is exerted on the powder material CP so as to compact it.

According to specific non-limiting embodiments (such as the one illustrated in figure 1), the compacting device also comprises a contrast belt 37 arranged on the opposite side of the conveyor belt 34 with respect to the pressure belt 36 to cooperate with the conveyor belt 34 for provide adequate feedback to the downward force exerted by the pressure tape 36. In particular, the pressure tape 36 and the backing tape 37 are (primarily) metal (steel) so that they cannot be substantially deformed while being exerted. pressure on the ceramic powder.

According to some embodiments not shown, the contrast belt 37 and the conveyor belt 34 coincide. In these cases, tape 34 ? (mainly) of metal (steel) and the contrast tape 37 ? absent.

According to some non-limiting examples, the containment chamber 24 comprises two walls (transverse, in particular perpendicular, to the direction A) facing each other (and preferably substantially parallel).

With particular reference to figures 14 and 15, according to some non-limiting embodiments, the feed device 10 comprises two lateral bulkheads 38 (which are configured to laterally contain the second powder SP while it descends from the outlet mouths 15 on the conveyor unit 5). The units? of lateral discharge 12 and l?unit? central exhaust 13 are arranged between the side bulkheads 38.

Thanks to the lateral bulkheads 38, the tendency of the first powder FP to slide laterally and therefore the tendency of the second parts SFP of the first powder FP to widen (bulge) is reduced.

In particular, are the side bulkheads 38 integral with the units? side discharge units 12 (and therefore move and rotate together with the side discharge units 12).

Pi? precisely but not necessarily, the lateral bulkheads 38 (substantially parallel to each other) extend from the outlet mouths 15 towards the conveyor unit 5 (in particular, towards the belt 34), in particular so as to arrive at a short distance from the conveyor unit 5 (in particular, a short distance from the belt 34; more particularly, a short distance from the aforementioned conveying plane of the conveyor unit 5).

Advantageously but not necessarily, the side walls 38 extend towards the conveyor unit 5 substantially perpendicular to the direction A.

According to some non-limiting embodiments, the feed device 9 comprises two central bulkheads 39 (which are configured to laterally contain the first powder SP while it descends from the outlet mouth 14 onto the conveyor unit 5). Are the two central bulkheads 39 each arranged between the unit? central unloading 13 and a respective one of the two units? side discharge 12.

Thanks to the central bulkheads 39, the tendency of the first powder FP to slide laterally and therefore the tendency of the first part FFP of the first powder FP to widen (bulge).

In particular, the central bulkheads 39 are integral with the units? central discharge units 13 (and therefore move and rotate together with the central discharge units 13).

Pi? precisely but not necessarily, the central bulkheads 39 (substantially parallel to each other) extend from the outlet mouth 14 towards the conveyor unit 5 (in particular, towards the belt 34), in particular so as to arrive at a short distance from the conveyor unit 5 (in particular, a short distance from the belt 34; more particularly, a short distance from the aforementioned conveying plane of the conveyor group 5).

Advantageously but not necessarily, the central bulkheads 39 extend towards the conveyor unit 5 substantially perpendicular to the direction A.

Advantageously but not necessarily, the central bulkheads 39 have a plurality of through holes. The through holes allow a partial penetration between the first FFP part of the first FP powder and the second SFP part of the first FP powder. In this way, especially when the first FFP part and the second SFP part have different colours, a more aesthetic effect is obtained. natural.

According to some non-limiting embodiments (and as illustrated in figure 7), the roller of the compression device 11 is arranged fixed in a given position between the feed device 9 and the feed device 10.

Alternatively (as illustrated in figures 14, 19, 20, 22, 23, 25, 26, 28, 29 and 31) according to some embodiments, the roller of the compression device 11 is mounted integral with the feed device 9. In this way, the roller is moved and/or rotated by the unit? handling 17 and/or the unit? of rotation 16, respectively, together with the feeding device 9 (more precisely, together with the lateral unloading units 12 and with the central unloading unit 13.

The structure and arrangement of the roller of the compression device 11 of the embodiments of Figs. 14, 16, 19-29 ? more simple and less cumbersome.

With particular reference to figures 16 to 18, according to some non-limiting embodiments, the unit? outlet 12 has an elongated cross-section (in particular, the outlet 14). For example, this elongated shape ? substantially rectangular (as illustrated in figures 16-18) or elliptical.

Advantageously but not necessarily, the compacting device 3 comprises a rotation device for rotating the outlet 14 (in particular, the central discharge unit 13) around a transversal axis (in particular, substantially perpendicular) to the plane conveyance of the conveyor group 5 (on which the conveying plane lies the first powder FP, while, in use, it is fed to the compacting device 3). Pi? precisely but not necessarily, the rotation device acts selectively on? unit? of central discharge 13 without rotating the unit? side discharge 12.

In this way ? It is possible to vary the width of the first FZ zone. For example, when the first and second powder FP and SP have different colors and you want to reproduce a natural material, by varying the width of the first area FZ ? Is it possible to obtain an aesthetically more? realistic.

Pi? in particular, this axis ? transversal (substantially perpendicular) to direction A of advancement. even more in particular, this axis passes through the center of the outlet mouth 14 (in particular, of the central unit 13).

For example, the rotation device can? include an electric motor configured to act on a shaft integral with? unit? central drain 13.

Advantageously, the compacting device 3 comprises a containment system for pushing (for example, by means of springs) the units? side discharge 12 towards the? unit? central discharge 13 in order to keep them in contact with the unit? central unit 13 itself (while the central unit 13 rotates on itself).

Advantageously but not necessarily (figures 20-25), the unit? central exhaust 13 ? configured to feed (carry) the first FFP part of the first FP powder to (on) the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane); the first part FFP ? a micronized powder (mainly consisting of particles having dimensions smaller than about 180 µm, in particular larger than about 30 µm). The units? side discharge conveyors 12 are instead configured to feed (carry) the second part SFP of the first powder FP to (onto) the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane); the second part SFP ? an atomized powder (mainly made up of particles having dimensions greater than 200 ?m, in particular less than 600 ?m).

In this way, the use of the micronized powder (more difficult to feed along ducts) is limited to the area that is? more important that it keeps its shape.

How more? easily observable by looking at figure 24, in particular (in these cases), the unit? central exhaust 13 ? configured so that the first FFP part of the first FP powder which is deposited on the conveyor group 5 (more precisely, on the belt 34; more precisely, on the conveyor plane) from the unit? central discharge channel 13 substantially having the first thickness (of height H -on the conveyor unit 5); the units? lateral discharge units 12 are configured so that the second part SFP of the first powder FP deposited on the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane) by the units? side discharge 12 substantially present the second thickness (or third thickness - of height HH - on the conveyor group 5).

In other words, in particular, the outlet mouth 14 ? arranged at height H while the outlet mouths 15 are arranged at height HH from the conveyor unit 5 (more precisely, from the belt 34; more precisely, from the conveyor plane).

In particular, it should be noted that, in this way, the compression device 11 (with reference to the embodiment of figures 20-22) does not act on the second part SFP of the first powder FP deposited on the conveyor unit 5 and (for all shapes embodiment of figures 20-25) this second SFP part does not interfere with the power supply device 10.

With particular reference to figures 20-22, according to some non-limiting embodiments, the units? discharge pipes 12 are arranged (along the section PA) downstream (in direction A) of the unit? central outlet 13, and, in particular, downstream (always in direction A) also of the compression device 11.

Advantageously but not necessarily, the units? lateral discharge 12 and central 13 are in any case integral with each other (and are, therefore, moved together by the rotation unit 16 and by the handling unit 17).

Advantageously but not necessarily, the feed device 9 also comprises a suction group 40, which ? configured to remove (by sucking) any particles of the first part FFP of the first powder FP arranged laterally to the first zone FZ (and, in particular, which are possibly not correctly compacted by the compression device 11). In this way, the risk of the ceramic articles T presenting aesthetic defects (e.g. some sort of burrs) is reduced.

In particular, the suction unit 40 ? arranged (along the PA section) downstream (in direction A) of the compressor station 11*. In other words, the suction unit ? arranged so as to remove any particles downstream (in direction A) of the compressor station 11* and upstream (in direction A) of the unit? side discharge 12.

According to some non-limiting embodiments, the suction unit 40 comprises two suction heads 41 arranged on opposite sides of the first zone FZ (in particular, downstream of the compression station 11* upstream of the lateral discharge units 12) .

Figures 23-25 show a variant of the plant 1 (in particular, of the feed device 9 and of the compacting device 11) of figures 20-22. In this case, the units? side discharge 12 are arranged upstream of the compacting station 11* and partially aligned (in the direction B) with the unit? central drain 13.

Advantageously but not necessarily (figures 26-31), the unit? central exhaust 13 ? configured to feed (carry) the first FFP part of the first FP powder to (on) the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane); the first part FFP ? an atomized powder. The units? side discharge conveyors 12 are instead configured to feed (carry) the second part SFP of the first powder FP to (onto) the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane); the second part SFP ? a micronized powder (mainly consisting of particles having dimensions smaller than about 180 µm, in particular larger than about 30 µm).

In this way, the micronized powder (more difficult to feed along ducts) is not used in the area that can? need to feed into particularly narrow ducts (e.g. when you want to obtain a thin grain).

How more? easily observable by looking at figure 27, in these cases, in particular, the unit? central exhaust 13 ? configured so that the first FFP part of the first FP powder which is deposited on the conveyor group 5 (more precisely, on the belt 34; more precisely, on the conveyor plane) from the unit? discharge conveyor 13 substantially having the second thickness (or third thickness - of height HH - on the conveyor unit 5); the units? lateral discharge units 12 are configured so that the second part SFP of the first powder FP deposited on the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane) by the units? side discharge conveyors 12 themselves substantially present the first thickness (of height HH - on the conveyor unit 5).

In other words, in particular, the outlet mouth 14 ? arranged at the height HH while the outlet mouths 15 are arranged at the height H from the conveyor unit 5 (more precisely, from the belt 34; more precisely, from the conveyor plane).

In particular, it should be noted that, in this way, the compression device 11 (with reference to the embodiment of figures 26-28) does not act on the first part FFP of the first powder FP deposited on the conveyor unit 5 and (for all shapes embodiment of figures 26-31) this first FFP part does not interfere with the feed device 10.

With particular reference to figures 26-28, according to some non-limiting embodiments, the unit? central exhaust 13 ? arranged upstream (in direction A) of the compacting station 11* and ? partially aligned with the unit? side discharge 12.

Figures 29-31 show a variant of the plant 1 (in particular, of the feed device 9 and of the compacting device 11) of figures 26-28. In this case, the unit? central exhaust 13 ? arranged (along the section PA) downstream (in the direction A) of the compacting station 11* and the feed device 9 comprises a dividing element 42, which ? adapted to limit (prevent) that the second part SFP of the first powder FP carried on the conveyor unit 5 by a first of the units? side discharge, on one side, and the second part SFP of the first powder FP carried on the conveyor unit 5 by a second of the units? side discharge, on the other side, approach.

In particular, the dividing element 42 ? arranged between the units? side discharge 12 and extends through the station 11* up to the unit? of central discharge 13. Pi? precisely, the dividing element 42 ? shaped so as to follow the profile of the compression device 11 (even more precisely of its compression roller), in particular without coming into contact with it.

With particular reference to figures 29-31, according to some non-limiting embodiments, the unit? central exhaust 13 ? disposed downstream (in the direction A) of the unit? side discharge 12, and, in particular, also downstream (always in the direction A) also of the compression device 11.

Advantageously but not necessarily, the units? lateral discharge 12 and central 13 are in any case integral with each other (and are, therefore, moved together by the rotation unit 16 and by the movement unit 17).

According to some non-limiting embodiments (see figures 32-34 in particular), the feed device 9 comprises a single unit? discharge tube 13 to feed the first powder FP to (on the entire useful surface of) the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane), where the first powder FP is? (whole) a micronized powder (mainly consisting of particles having dimensions smaller than about 180 ?m, in particular greater than about 30 ?m). In other words, the power device 9 ? configured to form a field full of micronized FP powder (mainly made up of particles having dimensions smaller than about 180 µm, in particular larger than about 30 µm).

In this way ? possible to obtain particular graphic effects both on the surface and in the mass.

Yes ? experimentally observed that (even in these cases) ? in any case, the presence of both the compression device 11 and the compacting device 3 is advantageous.

Indeed, in this way you get a better and more? homogeneous compression of the FP (micronized) powder. A single compression leads to an inhomogeneous KP compacted powder (with denser areas and less dense areas). This inhomogeneity? it had not been particularly detected when, previously, atomized powder was used.

About that, yes? experimentally observed that micronized powder tends to hinder (presumably due to its very nature - fine and irregularly shaped grains) more the escape of the air, present in the soft mass. Conversely, the atomized powder (presumably due to its spherical and regular shape) facilitates deaeration more during pressing, which therefore derives less benefit from the use of the additional compression device 11.

According to some non-limiting embodiments (see figure 32 in particular), the system 1 also comprises at least one tracer device 44, which ? configured to make insertions of another OP powder different from the first FP powder (for example, of a different colour) and ? arranged (along the section PA) upstream (in direction A) of the compacting device 3 and downstream (in direction A) of the inlet station 6.

In this way ? It is possible to create particular aesthetic effects (e.g. veins) potentially for the entire thickness of the CP powder material.

In particular, each tracking device 44 comprises an aspirator for removing part of the first powder FP (e.g. so as to create a furrow) and a unit? of deposition configured to insert the aforementioned other OP powder where the first FP powder? been removed (e.g. in the sulcus).

According to some non-limiting embodiments, each tracer device 44 is as described in the patent applications having publication numbers EP1787779A3 and WO2005/090024A1 by the same applicant.

Advantageously but not necessarily, the tracking device ? arranged (along the PA section) downstream (in direction A) of the compressor station 11*.

With particular reference to figures 35 and 36, according to some non-limiting embodiments, the plant 1 (more precisely, the feed device 9) comprises an adjustment device 45 which is ? disposed (along the section PA) upstream (in direction A) of the compacting device 3 and ? configured to adjust the width of the first powder FP (in particular, of the first zone FZ) on the conveyor unit 5 (in particular, on the compression belt 34; in particular, on the conveyor plane).

Advantageously but not necessarily, the adjustment device 45 comprises two movable belts 46 arranged on opposite sides of the first powder FP (of the first zone FZ) and a movement device (of a type known per se and not illustrated) for varying the? relative inclination of the two belts.

According to some specific and non-limiting embodiments currently in use, the feed device arranges the first and second part FFP and SFP of the first powder FP simultaneously on the belt 34 (of the conveyor unit 5 - see for example figure 5 and the left part of figure 7) with the first thickness corresponding to the height H.

At this point (see figure 8 and slightly to the right in figure 7), the compression device 11 exerts pressure on the first powder FP (towards the belt 34) so as to reduce its thickness to the second thickness corresponding to the height HH.

Subsequently (figure 9 and central part of figure 7), the feed device 10 carries (by gravity) the second powder SP onto the part of the conveyor unit 5 (more precisely, of the belt 34) not occupied by the first powder FP.

Thanks to the movement of the conveyor unit 5, the powdered material CP (composed of the first powder FP and the second powder SP) is then fed (figure 10 and right side of figure 7) towards the work station 4, where it is compacted (central part of figure 1) by the compacting device 3 in order to further reduce its thickness (fourth thickness, corresponding to the height HHH), reach a density of about 1.8-2.2 kg/dm<3 >and obtain the layer of compacted powder KP.

The layer of compacted powder KP is, at this point, cut, decorated and sintered so as to obtain the slabs 30.

Advantageously but not necessarily, the plant 1 ? configured to implement the method described below.

In accordance with a further aspect of the present invention, a method is provided for making ceramic articles T.

In particular, the method ? implemented by the plant 1 described above.

The method comprises a compaction step, during which a powder material CP comprising ceramic powder is compacted at a work station 4 so as to obtain a layer of compacted powder KP; a conveying phase, during which the powdered material CP is conveyed (in particular, in a substantially continuous manner) by a conveying unit 5 along a first section PA of a determined path (in a forward direction A) from a station inlet 6 to the work station 4 and the layer of compacted powder KP is transported by the conveyor unit 5 along a second section PB of the path determined by the work station 4 to an outlet station 7; and a feeding phase, during which the powdered material CP is fed onto (on the area CZ of) the conveyor unit 5 (the powdered material CP is fed onto the conveyor unit 5 so as to directly come into contact with the conveyor unit 5 ) at the entry station 6 by means of a power supply unit 8.

In particular, the conveying phase and the feeding phase are (at least partially) simultaneous. Additionally or alternatively, the compacting step and the conveying step are (at least partially) simultaneous. In addition or alternatively, the compaction phase and the feeding phase are (at least partially) simultaneous.

According to non-limiting embodiments, during the compaction phase, a pressure of at least 350 kg/cm<2 > is exerted (in particular, at least 380 kg/cm<2>; in particular, up to 450 kg/cm <2>; more specifically, up to 420 kg/cm<2>) on CP powder material.

In some non-limiting cases, the layer of compacted powder KP has a density (apparent) of at least about 1.8 kg/dm<3> (in particular, at least about 1.9 kg/dm<3>; in particular, up to about 2.2 kg/dm<3>; more particular, up to about 2.1 kg/dm<3>).

Advantageously but not necessarily, the powder material CP comprises a first powder FP (micronized) mainly consisting of particles having dimensions smaller than about 180 µm, in particular larger than about 30 µm. In particular, the first powder FP ? as defined above (relative to system 1). Pi? in particular, the CP powder material ? as defined above (relative to plant 1).

Yes ? it has been experimentally observed that the ceramic articles T obtained using this type of powder have surprisingly smaller areas? defined and, in the event that the powders have different colors, more aesthetic effects? precise and natural.

In particular, during the feeding phase, during the feeding phase, the first powder FP is fed to the conveyor unit 5 so as to come into contact with the conveyor unit 5.

Advantageously but not necessarily, the powder material CP comprises a second (atomized) powder SP predominantly consisting of particles having dimensions greater than 200 µm, in particular smaller than 600 µm. In particular, the second powder SP ? as defined above (relative to plant 1).

Using the second powder SP (in combination with the first powder FP) ? it was possible to simplify the procedure and reduce production costs. In fact, the SP powder has a lower cost (it is simpler to produce) and yes? proven to be easy to handle (being easier to transport in mass - it requires ducts with significantly smaller passage sections than those for micronized powders).

In this regard, it should be noted that It is known that to produce powder (ceramic - atomized) having the characteristics of the second powder SP, an atomization process is usually used which provides for spraying slip towards a jet of hot air. In contact with the hot air, the slip solidifies into particles having the dimensions indicated above (and in particular, also the angles of repose indicated above).

The first powder FP (or powder having its own characteristics ? micronized powder), on the other hand, is usually obtained starting from atomized particles (like those of the second powder SP) which are further treated by means of a pin mill.

The different type of production procedure results in different characteristics in the powders.

The second powder SP has density? apparent (ratio between the mass and the volume occupied without compressing the powder) normally around 0.8-1.2 kg/dm<3 >(typically, between about 0.95 and about 1.05 kg/dm< 3>).

The first FP powder has density? apparent (ratio between the mass and the volume occupied without compressing the powder) different (lower) from that of the second powder SP and normally around 0.65-0.70 kg/dm<3>, much lower than the density? apparent of the second SP powder (typically, between about 0.95 and about 1.05 kg/dm<3>).

Yes ? experimentally observed that by imposing a different compaction ratio (relationship between final density and initial density) between the two materials which at the time of forming by pressing are surprisingly obtained ceramic products T and the layer of compacted powder KP more? resistant (with reduced internal stresses). Pi? precisely but not necessarily, the compaction ratio of the first powder FP and the compaction ratio of the second powder SP (and, therefore, the first, second, third and fourth thicknesses) are selected so that (they are such that) the densities? of the first FP powder and the second SP powder after the compaction phase have a difference of less than 0.05 kg/dm<3 > (in particular, less than or equal to 0.03 kg/dm<3>; more specifically , less than or equal to 0.02 kg/dm<3>; even more particularly, they are substantially equal).

According to some non-limiting embodiments, given the objective value (which one wishes to obtain) of density? in green (density of the layer of compacted powder KP) of about 2.00 kg/dm<3 >(with a compaction pressure of about 400 kg/cm<2>), the compaction ratio ? about 2.0-2.1 for the second powder SP and 2.85-3.0 for the first powder FP.

How already? indicated above, the comparison between figures 6 and 3 (and between figures 2 and 4) shows the different behavior of atomised powders at a low angle of repose (figures 6 and 2) and the first micronized FP powder, which, advantageously but not to a limited extent, it has a high angle of repose.

According to some non-limiting embodiments (figure 7), the feed phase comprises a first feed sub-phase, during which the first powder FP is fed onto (in direct contact with) a first part (of the aforementioned zone CZ) of the conveyor unit 5 from a feed device 9 of the feed unit 8 so as to have a first thickness (ie a height with respect to the conveyor unit); and a second feed sub-phase, during which the second powder SP is fed onto (in direct contact with) a second part other than the aforementioned first part (of said zone CZ) of the conveyor unit 5 by a feed device 10 of said power pack 8.

Advantageously but not necessarily, the method also comprises a compression step (figure 8), which takes place in a compression station 11* upstream (with respect to the direction of advancement A), in particular along the first section PA, of the working station 4 and during which the first powder FP arranged on said conveyor unit 5 is compressed so as to have a second thickness lower than the first thickness.

Yes ? observed experimentally that in this way the tensions in the ceramic articles T are surprisingly reduced. Yes ? assumed that there? is due to the fact that in this way the densities are approached? apparent of the first powder FP and the second powder SP.

According to some non-limiting embodiments, during the second feed sub-phase (Figure 9), the second powder SP is fed to the conveyor unit 5 so as to have a third thickness lower than the first thickness, in particular substantially equal to the second thickness.

It should be noted that, advantageously but not necessarily, the first thickness and the second thickness (and therefore the third thickness) are selected so that, after the compression phase and the compaction phase, the density? apparent of the first powder FP is similar to the density? apparent density of the second powder SP (in particular, between 1.8 and 2.2 Kg/dm<3>; more precisely, as indicated above in relation to the apparent density of the layer of compacted powder KP).

Again, yes? observed experimentally that it is surprisingly possible to obtain particularly solid ceramic articles T (with particularly low internal tensions).

According to specific and non-limiting embodiments, the first thickness (corresponding ? equal ? to a height H), the second thickness (corresponding ? equal ? to a height HH), the third thickness (corresponding ? equal ? to the? height HH) and the fourth thickness (corresponding ? equal ? to a height HHH) are selected so that the following relationship is satisfied:

D1 = D2 ? 0,030 Kg/dm<3 >(preferably but not necessarily, D1 = D2 ? 0,020 Kg/dm<3>)

in which

D1 = HH/HHH x SD

D2 = H/HHH x DF

in which DS ? the density? apparent of the second powder SP; DF ? the density? apparent of the first FP powder.

Advantageously but not necessarily (again in this context), the compaction ratio applied to the first powder FP following the compression phase and the compaction phase ? about 2.60 to about 3.2 (specifically, about 2.75 to about 3.1). Additionally or alternatively, the compaction ratio applied to the second powder SP following the compaction step ? about 1.7 to about 2.4 (specifically, about 1.9 to about 2.2).

For compaction ratio we mean the ratio between the density? (of the first and/or second powder FP and SP) after and before the compaction and possibly compression step.

According to some non-limiting embodiments, at least a part of the first powder FP has a first colour. In particular, the particles of the first powder FP have (are) predominantly (of) a first color.

Advantageously but not necessarily, the particles of the second powder SP have (are) predominantly (of) a second color (e.g. white) different from the first color (e.g. black).

According to some non-limiting embodiments, during the feeding phase the layer of material in powder form CP is obtained, which has at least a first zone FZ with a prevalent content of the first powder FP and at least a second zone SZ with a prevalent content of the second powder SP.

Advantageously but not necessarily, the layer of powder material CP has a third zone TZ, which is arranged between the first zone FZ and the second zone SZ of the layer of powder material CP and has a prevalent content of (in particular, it consists of) the first powder FP. In these cases, in particular, the particles of the second powder SP and the particles of the first powder FP of the third zone TZ of the powder material layer CP predominantly have a (same) second color different from the first color of the first powder FP of the first zone FZ.

In this way, yes? observed experimentally that the definition of the particle distribution of the first powder FP of the first zone FZ ? been surprisingly further increased. Yes ? assumed that there? is due to the fact that it is made more? difficult that agglomerations of dimensions pi? large (and, therefore, visible) particles of the second powder SP can mix with the particles of the first powder FP of the first zone FZ.

According to some non-limiting embodiments (such as the one illustrated), the first feed sub-phase takes place at a feed station 22 upstream (with respect to the direction of advancement A), in particular along the first section PA, of a station of supply 23, in correspondence of which the second sub-phase of supply takes place. In these cases, in particular, the compressor station 11* ? arranged (along the first section PA) between the feed station 22 and the second feed station 23.

Advantageously but not necessarily, the feed device 9 in turn comprises at least two units side discharge 12 and at least one?unit? of central unloading 13. In particular, the unit? central exhaust 13 ? arranged between the two units? side discharge 12. During the feeding phase, the unit? central discharge unit 13 carries a first FFP part of a first FP powder on the conveyor unit 5 and each unit? side discharge 12 arranges a respective second part SFP of the first powder FP on the conveyor unit 5 to the sides and in contact with the first part FFP of the first powder FP so that the second SFP parts of the first powder FP laterally support and limit the movements of the first FFP part of the first FP powder.

In this way, surprisingly, a further improvement in the positioning accuracy of the first FP powder is obtained (which is supported laterally and, therefore, further reduces the possibility of smudging).

In particular, it should be noted that the first part FFP defines the first zone FZ of the layer of the powder material CP (therefore, the particles of the first part FFP are of the same type ? are they the same ? and are defined as those of the first zone FZ) . Additionally or alternatively, the second SFP part defines the third TZ zone of the CP powder material layer (therefore, the particles of the second SFP part are of the same type ? are they the same ? and are defined as those of the third TZ zone) .

According to some non-limiting embodiments, the units? side discharge 12 and the unit? discharge pipes 13 (they are substantially integral with each other and) are substantially aligned with each other (during the feeding phase) in an alignment direction B (in particular, transverse to the direction A).

Pi? precisely, but not necessarily, during the power supply, the unit? side discharge 12 and the unit? discharge unit 13 are rotated (so as to change the orientation of the relative position of the side discharge units 12 and the central discharge unit 13).

Pi? in particular, the units? side discharge 12 and the unit? central discharge tube 13 are rotated so as to change the alignment direction B. In particular, the units side discharge 12 and the unit? of central unloading 13 rotate about an axis AA substantially perpendicular to the direction A. In particular, the axis AA ? substantially perpendicular to the aforementioned conveying plane (on which the first powder FP lies and is fed towards the outlet station).

According to some non-limiting embodiments, axis AA passes through unit? central exhaust outlet 13 (more precisely, through its center).

In particular, the first part of the conveyor unit 5 on which the first powder FP is fed (in particular, deposited), has a position on the conveyor unit 5.

Advantageously but not necessarily, during the first feed sub-phase, the position of the first part (of the cited area CZ) of the conveyor unit 5 is modified (moved) so as to achieve the distribution (of a given shape) of the first powder FP on the unit conveyor 5. In particular, the position of the first part (of the cited area CZ) of the conveyor unit 5 is moved in a transversal direction C (more specifically, perpendicular) to the forward direction A (in which the conveyor unit 5 conveys the material in powder CP along the first section PA towards the work station 4).

Alternatively or in addition, during the power supply phase (in particular during the first sub-phase of power supply) a unit? movement 17 moves the feed device 9 (in particular in the direction C transversal to the feed direction A) so that the feed device 9 can carry out the distribution (of a determined shape) of the first powder FP on the conveyor unit 5, in particular on the mentioned conveyance plan.

According to some non-limiting embodiments, the first part FFP and the second part SFP of the first powder FP are (both) micronized powders (mainly made up of particles having dimensions smaller than about 180 ?m, in particular larger than about 30 ?m ).

With particular reference to figures 20-25, advantageously but not necessarily, the first part FFP ? a micronized powder (mainly consisting of particles having dimensions smaller than about 180 µm, in particular larger than about 30 µm); and the second part SFP ? an atomized powder (mainly made up of particles having dimensions greater than 200 ?m, in particular less than 600 ?m).

In these cases, in particular, the first FFP part of the first FP powder which is deposited on the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane) from the unit? discharge conveyor 13 itself substantially has the first thickness (of height H - on the conveyor unit 5); and the second SFP part of the first FFP powder deposited on the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane) from the units? lateral discharge conveyor 12 itself substantially has the second thickness (or third thickness - of height HH - on the conveyor unit 5).

In these cases, only the first FFP part is compressed during the compression phase. In other words, more precisely, the second part of the SFP pu? be considered included in the second powder SP.

With particular reference to figures 26-31, advantageously but not necessarily, the first part FFP ? an atomized powder (mainly consisting of particles having dimensions greater than 200?m, in particular less than 600?m); and the second part SFP ? a micronized powder (mainly consisting of particles having dimensions smaller than about 180 µm, in particular larger than about 30 µm).

In these cases, in particular, the first FFP part of the first FP powder which is deposited on the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane) from the unit? discharge conveyor 13 itself substantially has the second thickness (or third thickness - of height HH - on the conveyor unit 5); and the second SFP part of the first FFP powder deposited on the conveyor unit 5 (more precisely, on the belt 34; more precisely, on the conveyor plane) from the units? side discharge conveyor 12 substantially has the first thickness (of height H -on the conveyor unit 5).

In these cases, only the second SFP part is compressed during the compression phase. In other words, more precisely, the first part FFP can? be considered included in the second powder SP.

According to some non-limiting embodiments, both the first part FFP and the second part SFP of the first powder FP are fed (along the section PA) upstream of the compression station 11*.

Advantageously but not necessarily (figures 20-22), the second SFP part is fed to (on) the conveyor assembly 5 (in particular, on the belt 34; in particular, on the conveyor plane) downstream (in direction A) of the filling station compression 11*.

In these cases, only the first FFP part is compressed during the compression phase. In other words, more precisely, the second part of the SFP pu? be considered included in the second powder SP.

Advantageously but not necessarily (figures 29-31), the first part FFP is fed to (on) the conveyor unit 5 (in particular, on the belt 34; in particular, on the conveyor plane) downstream (in direction A) of the filling station compression 11*.

In these cases, only the second SFP part is compressed during the compression phase. In other words, more precisely, the first part FFP can? be considered included in the second powder SP.

Advantageously but not necessarily, the method comprises a printing step, which ? subsequent to the compacting phase and during which a graphic decoration is created on (over) the layer of compacted ceramic powder KP transported by the conveyor unit 5 at a printing station 19 along the path determined downstream of the workstation 4. In particular, a?unit? control 20 controls the printing phase so as to create a graphic decoration coordinated with the distribution of the first powder FP on the conveyor unit 5.

Advantageously but not necessarily, the method comprises a removal step, during which a surface portion of the powder material CP arranged on the conveyor unit 5 is removed (in particular, by suction) at a removal station 27 arranged downstream ( with respect to the advancement direction A), in particular along the first section PA, of the inlet station 6 (more precisely, of the feed stations 22 and 23).

According to some non-limiting embodiments, the method comprises a cutting step, during which the layer of compacted powder KP is cut so as to obtain plates 30.

In particular, the method comprises a firing step for sintering the layer of compacted powder KP of the slabs 30 so as to obtain the ceramic articles T; in particular, the cooking phase takes place by means of a cooking oven 33 arranged along the path determined downstream of the printing station 19.

Unless otherwise explicitly indicated, the content of the references (articles, books, patent applications, etc.) cited in this text ? referred to here in full. In particular the mentioned references are incorporated herein by reference.

Claims (10)

R E V E N D I C A T I O N S 1.- Plant for the production of ceramic articles (T); the plant (1) comprises a compacting machine (2) for compacting a powder material (CP) comprising ceramic powder; the compacting machine (2) comprises a compacting device (3), which ? arranged at a workstation (4) and ? configured to compact the material into powder (CP) so as to obtain a layer of compacted powder (KP); a conveyor unit (5) to transport the material in powder form (CP) along a first section (PA) of a path determined from an inlet station (6) to the work station (4) and the layer of compacted powder (KP) along a second section (PB) of the path determined by the work station (4) to an output station (7); and a power supply unit (8), which ? configured to feed the powder material (CP) to the conveyor unit (5) at the entry station (6); the plant (1) ? characterized in that the feed unit (8) comprises a first feed device (9), which ? configured to feed a first powder (FP) to the conveyor unit (5); does the first feed device (9) in turn comprise at least two units? side discharge (12) and at least one? unit? of central discharge (13), which and ? configured to carry a first part (FFP) of a first powder (FP) on the conveyor unit (5); each unit? side discharge (12) ? configured to arrange a respective second part (SFP) of the first powder (FP) on the conveyor unit (5) at the sides and in contact with the first part (FFP) of the first powder (FP) so that the second parts (SFP) of the first powder (FP) laterally support and limit the movements of the first part (FFP) of the first powder (FP). 2.- Plant according to claim 1, in which the unit? central exhaust (13) ? disposed between the said at least two units? side discharge (12); the units? side discharge (12) and the unit? discharge pipes (13) are substantially aligned with each other in an alignment direction (B); the power supply unit (8) comprising a? unit? of rotation (16) which ? configured to rotate the unit? side discharge (12) and the unit? central outlet (13) so as to change the alignment direction (B); in particular, the said unit? of rotation (16) ? configured to rotate the unit? side discharge (12) and the unit? discharge outlet (13) around an axis (AA) substantially perpendicular to a conveying plane of the conveyor unit (5). 3.- A plant according to Claim 1 or 2, in which the feed group (8) comprises a unit? of handling (17) which ? able to move the first feed device (9) (in particular in a direction transverse to a feed direction (A) in which the conveyor unit (5) conveys the first powder (FP) towards the second feed device (10)) so that the first feed device (9) can distribute the first powder (FP) on the conveyor unit (5), in particular on said conveyor plane. 4.- Plant according to any one of the preceding claims, wherein the first feeding device (9) is? configured to feed the first powder (FP) to the conveyor assembly (5) so that the first powder (FP) substantially has a first thickness on the conveyor assembly (5); the unit? central discharge outlet (13) has an outlet (14) facing the conveyor unit (5) and spaced from the conveyor unit (5) by a height (H) substantially equal to said first thickness; each unit? side discharge (12) has a respective outlet (15) facing the conveyor unit (5) and spaced from the conveyor unit (5) by a height (H) substantially equal to said first thickness. 5.- Plant according to claim 4, wherein the first feeding device (9) is arranged along the first section (PA) and ? configured to feed the first powder (FP) mainly consisting of particles having dimensions of less than 180 ?m (in particular, greater than 30 ?m) to the conveyor unit (5) on a first part of the conveyor unit (5); the plant (1) also comprises a second feed device (10), which ? arranged along the first section (PA) and ? configured to feed a second powder (SP) mainly consisting of particles having dimensions greater than 200?m (in particular less than 600?m) onto a second part of the conveyor unit (5) different from said first part of the conveyor unit (5) ; and a compression device (11), which ? arranged at a compression station (11*) along the first section (PA) upstream of the work station (4) and downstream of the first feed device (9) and ? configured to compress the first powder (FP) so that the first powder (FP) has a second thickness lower than the first thickness. 6.- Plant according to claim 5, wherein the first feeding device (9) is arranged upstream of the second feed device (10); the compression device (11) ? disposed between the first feed device (9) and the second feed device (10); in particular, the second feeding device (10) ? configured to feed the second powder (SP) to the conveyor unit (5) so that the second powder (SP) has a third thickness on the conveyor unit (5); the third thickness being substantially equal to the second thickness. 7.- Method for making ceramic articles (T), the method includes: a compacting step, during which a material in powder form (CP) comprising ceramic powder is compacted at a work station (4) so as to obtain a layer of compacted powder (KP); a conveying phase, during which the material in powder form (CP) is conveyed (in particular, in a substantially continuous way) by a conveying unit (5) along a first section (PA) of a path determined by an infeed station ( 6) to the work station (4) and the layer of compacted powder (KP) is transported by the conveyor unit (5) along a second section (PB) of the path determined by the work station (4) to an output station (7 ); a feeding phase, during which the material in powder form (CP) is fed to the conveyor assembly (5) at the entry station (6) by means of a feeding assembly (8); in particular, the conveying step and the feeding step are at least partially simultaneous; the method ? characterized in that the material in powder form (CP) comprises a first powder (FP); during the feeding phase, a first feeding device (9) of the feeding unit (8) feeds the first powder (FP) to the conveyor unit (5); does the first feed device (9) in turn comprise at least two units? side discharge (12) and at least one? unit? central drain (13); during the power supply phase, the unit? central discharge (13) carries a first part (FFP) of said first powder (FP) on the conveyor unit (5) and each unit? discharge side (12) arranges a respective second part (SFP) of the first powder (FP) on the conveyor unit (5) to the sides and in contact with the first part (FFP) of the first powder (FP) so that the second parts ( SFP) of the first powder (FP) laterally support and limit the movements of the first part (FFP) of the first powder (FP). 8.- Method according to claim 7, the unit? central exhaust (13) ? disposed between the said at least two units? side discharge (12); the units? side discharge (12) and the unit? discharge pipes (13) are substantially aligned with each other in an alignment direction (B); during the power supply phase, the unit? side discharge (12) and the unit? discharge center (13) are rotated so as to change the direction (B) of alignment; in particular, the units? side discharge (12) and the unit? central unloading wheels (13) rotate around an axis (AA) substantially perpendicular to a conveying plane, on which the first powder lies and is fed by the conveying unit (%) towards the outlet station (7); in particular, the said axis (AA) ? substantially perpendicular to said advancement direction (A). 9. A method according to claim 7 or 8, wherein, during the power supply phase (in particular during the first power supply sub-phase) a unit? movement (17) moves the first feed device (9) (in particular, in a transverse direction to a forward direction (A) in which the conveyor unit (5) conveys the first powder (FP) towards the work station (4)) so that the first feed device (9) can distribute the first powder (FP) on said conveyor unit (5), in particular on said conveyor plane. 10.- Method according to any one of claims from 7 to 9, during the feeding phase a layer of material in powder form (CP) is obtained, which has at least one first zone (FZ) with a prevalent content of the first powder (FP ) and at least one second zone (SZ) with a prevalent content of a second powder (SP); the first powder (FP) ? predominantly made up of particles having dimensions of less than 180 ?m, in particular greater than 30 ?m; the second powder (SP) ? predominantly made up of particles having dimensions greater than 200 ?m, in particular less than 600 ?m; in particular, the first powder (FP) has an angle of repose greater than 55?, in particular greater than 65? (more specifically, less than 90?); in particular, the second powder (SP) has an angle of repose lower than 45? (more specifically, above 20?).