WO2023199218A1

WO2023199218A1 - Manufacturing system and method to manufacture ceramic articles

Info

Publication number: WO2023199218A1
Application number: PCT/IB2023/053695
Authority: WO
Inventors: Andrea Valli; Paolo TESTI
Original assignee: Sacmi Cooperativa Meccanici Imola Societa' Cooperativa
Priority date: 2022-04-14
Filing date: 2023-04-11
Publication date: 2023-10-19

Abstract

Process and system (1) for manufacturing ceramic articles (T). The manufacturing system (1) comprises: a feeding assembly (2) for feeding powder ceramic material (CP); a compaction device (4); a conveyor assembly (6) to transport powder ceramic material (CP) along a given path (P) in a moving direction (A); a de-aeration unit (8) arranged upstream of the compaction device (4) along said given path (P), for transmitting a vibration with at least a sussultatory component, i.e. along a vertical direction, to the powder ceramic material (CP) which, in use, is arranged at a segment (PA) of said given path (P) so as to thicken said powder ceramic material (CP) and obtain a layer of thickened powder which is then compacted by the compaction device (4). The segment (PA) has a length between 0.5 m and 2 m.

Description

MANUFACTURING SYSTEM AND METHOD TO MANUFACTURE CERAMIC

ARTICLES

Cross-Reference to Related Applications

This Patent Appl ication claims priority from Italian Patent Application No . 102022000007550 filed on April 14 , 2022 the entire disclosure of which is incorporated herein by reference .

Field of the Art

The present invention relates to a manufacturing system and method to manufacture ceramic articles ; in particular, ceramic slabs and tiles .

Background of the Invention

In the field of ceramic article production, the known methods and systems to manufacture ceramic articles , in particular ceramic slabs and tiles , provide feeding semi-dry powders ( in particular, with a moisture content of circa 5 % - 7 % ) and subsequently pressing this ceramic powder to obtain a layer of compacted ceramic powder .

The compaction step, whether it is carried out with continuous or discontinuous systems , is particularly delicate since an incorrect execution of this step may lead to the appearance of cracks and other defects , at least in part due to the failure to deaerate the ceramic powder during the compaction step . In fact , the powder material typically used in the ceramic field, having a grain si ze ranging from 200 to 600 pm, has a percentage of air therein that constitutes more than 50% of its total volume . Therefore , the processing of the powder ceramic material , and in particular the compaction thereof , requires firstly, during the so-called deaeration step, removing a large volume of intergranular air from the spaces between the ceramic powder particles or grains , and then applying a compaction pressure . In other words , in order to carry out a proper compaction, it is therefore necessary to firstly remove at least part of the high volume o f air from the intergranular spaces before proceeding with the actual compaction .

Such a deaeration step is generally carried out with a very gentle increase in compaction pressure , in order to give the air time to escape through the intergranular spaces . In detail , in traditional hydraulically controlled discontinuous presses , this deaeration step is carried out by appropriately controlling the hydraulic circuits in order to correctly calibrate the piston displacement , both in terms of speed and applied force . Instead, in continuous compaction systems , this deaeration step is carried out by placing the upper compacting belt as inclined with respect to the transit plane of the ceramic powder so as to form a progressive reduction of the port existing between the upper ( inclined) belt and the lower belt on which the ceramic powder transits , so as to gradually increase the compaction force, giving the air between the grains time to be expelled .

It is clear from the foregoing that this air evacuation step slows down the manufacturing cycle of ceramic articles as it requires a gradual pressing that must take place slowly to ensure the proper deaeration of the ceramic powder .

It is also clear that this evacuation step will be all the longer the greater the thickness of the ceramic powder to be compacted .

This results in limitations in terms of maximum processable thickness ( and thus in terms of thickness of ceramic articles ) at the same production speed, and/or in terms of production speed at the same thickness and compaction quality .

The following documents related to systems for manufacturing ceramic articles of the known types using conventional presses are reported : document CN201244859Y which relates to a feeding device for manufacturing ceramic coatings ; document JPH10264134A which relates to a method and equipment for feeding powder material to a conventional- type discontinuous press ; document CN205685520U which focuses on a grid for loading a conventional-type discontinuous press ; and document JP2008194987A which relates to a method for forming large-si zed ceramic articles using conventional-type presses .

Also noteworthy are WO2021048797A1 related to equipment for manufacturing ceramic and/or stone slabs , and document KR20160149306A describing a method and system for manufacturing ceramic articles by means of a continuous compaction system .

Disclosure of the Invention

Aim of the present invention is to provide a system and a process to manufacture ceramic articles , which make it possible to overcome , at least partially, the limitations of the prior art , while making it possible to increase the production speed and the thickness of the layer of ceramic powder that can be processed with the same compaction quality .

According to the present invention there are provided a method and a system to manufacture ceramic articles as set forth in the following independent claims and, preferably, in any one of the claims directly or indirectly dependent on the independent claims .

The claims describe preferred embodiments of the present invention .

Brief Description of the Drawings

The invention wi ll now be described with reference to the accompanying drawings , which illustrate some nonlimiting embodiments , wherein :

- Figure 1 shows a schematic side view of a part of a manufacturing system of ceramic articles according to an embodiment of the present invention;

- Figure 2 shows a schematic side view of a part of a manufacturing system of ceramic articles according to a further embodiment of the present invention;

- Figure 3 shows a schematic side view of a part of a manufacturing system of ceramic articles according to yet another embodiment of the invention; and Figure 4 shows a diagram of the particle size distribution of the ceramic powder used to manufacture ceramic articles.

Preferred Embodiments of the Invention

In the attached figures, number 1 globally denotes a system to manufacture ceramic articles T. In particular, ceramic articles T are substantially (but not necessarily) flat articles, in particular ceramic slabs; more precisely, ceramic tiles of different sizes, e.g. large sizes such as those having a cross-section of 1200/1800 x 2400/3600mm, or smaller sizes having a cross-section of 900/1200xl800/2000mm, up to 400x400mm) , etc., and a thickness ranging from circa 3 to circa 50mm, preferably from 6mm to circa 30mm.

The manufacturing system 1 of ceramic articles T comprises: a feeding assembly 2 configured to feed powder ceramic material CP to an input station 3; a compaction device 4 arranged at a compaction station 5, and configured to compact the powder ceramic material CP (in particular, as will be explained hereinafter, a layer of thickened powder S comprising -formed by - the powder ceramic material CP) so as to obtain (i.e. form) a layer of compacted powder KP; and a conveyor assembly 6 configured to transport the powder ceramic material CP along a given path P extending in a moving direction A at least from the input station 3 to the compacting station 5, and the layer of compacted powder KP along the same given path P at least out of the compaction station 5 (see Figures 1, 2 and 3) .

Advantageously but not limitatively, the feeding assembly 2 comprises at least one feeding device 7 of the known type and not further described herein, e.g. a hopper, for feeding a (dosed) quantity of powder ceramic material CP at the input station 3.

Advantageously but not limitatively, the ceramic articles T comprise (in particular, are formed by) powder ceramic material CP comprising clay, sand, feldspars and other minerals , which are ground together and atomised to obtain a homogenous composition .

Furthermore , advantageously but not necessarily, such powder ceramic material CP comprises ( in particular, is formed by) semi-dry ceramic powder having a moisture content ranging from circa 5% to circa 10% and a measured particle si ze ranging from circa 200 pm to circa 600 pm, as can be seen from the particle si ze curve shown in Figure 4 , which shows in the abscissa the si ze , in particular the equivalent diameter, of the particles forming the powder ceramic material CP and in the ordinate the % of material having such si ze characteristics included in the above-mentioned powder ceramic material CP .

In advantageous but non-limiting detail , this particle si ze curve was constructed by means of a sieving device comprising sieves with ports having a decreasing si ze ranging from circa 600 pm to circa 63 pm .

Advantageously but not limitatively, the manufacturing system 1 of ceramic articles T also includes at least one ceramic article firing kiln ( known as such and not further described or shown herein) configured to fire base ceramic articles CB, which comprise the layer of compacted ceramic powder KP ( in particular, they are formed from at least part of the layer of compacted ceramic powder KP ) , to obtain the finished ceramic articles T , i . e . ceramic slabs or tiles .

Furthermore , advantageously, the manufacturing system 1 of ceramic articles T comprises a deaeration unit 8 ( i . e . a thickening unit 8 ) which is arranged ( in particular, immediately) upstream of the compaction device 4 along the given path P and is configured to transmit a vibrational action ( schematically shown in Figures 1 to 3 ) to the powder ceramic material CP which, in use , is located ( i . e . passes/ transits ) at a segment PA of the given path P so as to thicken the powder ceramic material CP and obtain a layer of thickened powder S , which, as mentioned above , is then compacted by the compaction device 4 . In detail , advantageously, the compaction device 4 is conf igured to transmit a compaction pressure to the layer of thickened powder S to obtain the above-mentioned layer of compacted powder KP .

Advantageously but not limitatively, said segment PA of the given path P concerned with the aforementioned vibrational action ( i . e . at which it is transmitted) extends ( immediately) upstream of the compaction station 5 and has an extension ranging from at least circa 0 . 5 m up to circa

2 m, in particular from circa 1 m to circa 1 . 5 m . Even more advantageously, but not limitatively, such a segment PA of the given path P extends between the input station 3 and the compaction station 5 , even more advantageously such a segment PA comprises a part of the given path P which starts ( i . e . begins ) immediately after the input station 3 and extends for a length ranging from circa 0 . 5 m to circa 2 m in the moving direction A.

According to other advantageous but non-limiting embodiments not shown, the conveyor assembly 6 comprises : an upper conveyor device , for example a conveyor belt extending along a first branch of the path P determined from the input station 3 to a discharge station; a lower conveyor device , which is arranged at a lower height than the upper conveyor device and extends along a second branch of the path P determined downstream of the first branch, and a so-called pen device arranged at the discharge station, immediately downstream of the upper conveyor device and immediately upstream of the lower conveyor device along the path P determined and configured to receive the layer of thickened powder S from the upper conveyor device and guide it onto the lower conveyor device . In this case , advantageously but not limitatively, the segment PA of the given path P concerned with the aforementioned vibrational action ( i . e . at which the is transmitted) extends along the first branch of the given path P, in particular between the input station

3 and the discharge station, and has an extension ranging from at least circa 0.5 m to circa 2 m; in particular, from 1 m to circa 1.5 m.

The segment PA is, advantageously, dimensioned to ensure the thickening of the powder material CP that, in use, lies and moves along this segment PA, thanks to the vibrational action transferred by the aforementioned deaeration (i.e. thickening) unit 8.

According to some advantageous but non-limiting embodiments, the conveyor assembly 6 is configured to move the powder ceramic material CP at least along the segment PA with a moving speed ranging from circa 1 metre per minute (in particular, from circa 5 metres per minute) to circa 100 metres per minute (in particular, to circa 12 metres per minute) . This ensures that the powder ceramic material CP is subjected to the vibrational action for a time sufficient to ensure the proper thickening of the powder ceramic material CP itself, i.e. the removal of at least part of the intergranular air contained between the grains of the powder ceramic material CP.

In detail, in the present disclosure, the expression deaeration, i.e. thickening, of the powder ceramic material CP refers to the evacuation of at least part (advantageously, most) of the air present between the grains of the powder ceramic material CP.

Advantageously, but not limitatively, the above- mentioned vibrational action used to achieve such deaeration/ thickening has a vibration frequency ranging from circa 1 Hz (in particular, from circa 10 Hz) to circa 1000 Hz (in particular, to circa 200 Hz) .

Furthermore, advantageously but not limitatively, the aforementioned vibrational action has at least one (in particular, it is a substantially) sussultatory component. In other words, advantageously but not limitatively, said vibrational action comprises at least one movement component along a vertical direction (in particular, said vertical direction is substantially perpendicular to the moving direction A; even more particularly, said vertical direction is substantially perpendicular to a moving plane de fined by the conveyor assembly 6 along the aforementioned given path P ) ; more particularly, said vibrational action compri ses ( in particular, is ) a substantially vertical action .

According to some advantageous but non-limiting embodiments ( such as , for example , those shown) , the conveyor assembly 6 comprises at least one transporter 9 extending from the input station 3 to the at least one compaction station 5 passing through at least the segment PA of the given path P, and the deaeration/ thickening unit 8 comprises at least one vibration generator 10 to generate the aforementioned vibrational action, and at least one transmission element 11 in connection ( advantageously, but not limitatively, mechanically) with the transporter 9 to trans fer the vibrational action from the vibration generator 10 to the transporter 9 ( e . g . a conveyor belt or a trolley as will be further explained below) to ( at least ) the segment PA of the given path P, so as to trans fer said vibrational action to the powder ceramic material CP, which is located on ( i . e . passes/ transits along) said segment PA, and thicken it .

Advantageously but not limitatively, the vibration generator 10 comprises ( in particular, consists of ) an eccentric motor o f the known type and not further described herein, adapted to generate the above-described vibrational action . In particular, according to certain advantageous but non-limiting embodiments , the vibration generator 10 comprises ( in particular, consists of ) a mechanical system adapted to vibrate a mass of at least circa 0 . 1 kg and less than circa 10 kg with a vibration frequency of at least circa 1 Hz , in particular ranging from at least circa 1 HZ to circa 1000 Hz ( in particular, from at least circa 10 Hz to circa 200 Hz ) .

It is understood that according to other advantageous but non-limiting embodiments , the vibration generator 10 could be of the electromagnetic, pneumatic, or piezoelectric type conveniently put in (advantageously mechanical) communication with the transporter 9 at least at the segment PA of the given path P.

In particular, advantageously but not limitatively, the transmission element 11 comprises (in particular, is formed by) a plate (advantageously but not limitatively) arranged under and in contact with the transporter 9. Such a plate, advantageously but not limitatively, has a length (i.e. an extension along said moving direction A) ranging from at least circa 0.5 m to circa 2 m so as to affect and transmit the vibrational action to the powder ceramic material CP along the entire segment PA.

In detail, in the embodiments shown in the attached figures, the vibration generator 10 is arranged under and in contact with the transmission element 11, in particular with the plate, which in turn is in contact with the transporter 9.

According to alternative embodiments not shown, the vibration generator 10 is arranged spaced apart (in other words, not in contact) with respect to the transmission element 11 and the manufacturing system 1 (in particular, the deaeration/ thickening unit 8) comprises a mechanical transmission system configured to transmit the vibration to the transmission element 11; for example, the vibration generator 10 could be arranged above the conveyor assembly 6 to facilitate access thereof, for example in case of adjustment, maintenance operations, etc.

According to still other, not shown and non-limiting embodiments, the vibration generator 10 comprises (in particular, consists of) an acoustic wave generator, e.g. a loudspeaker adapted to generate acoustic waves of a suitable frequency arranged so as to transfer this vibration and generate the aforementioned vibrational action. Alternatively or additionally, according to certain nonlimiting and not shown embodiments, the vibration generator 10 could be arranged so as to trans fer the vibrational action to the powder ceramic material CP immediately downstream of the feeding station 2 , in particular of the feeding device 7 , so as to thicken powder ceramic material CP as soon as it is fed ( even before it arrives ) on the conveyor assembly 6 .

According to some advantageous but non-limiting embodiments ( such as those shown in Figure 2 ) , the conveyor assembly 6 is configured to transport the powder ceramic material CP, the layer of thickened powder S and the layer of compacted powder KP along the given path P in a substantially continuous manner . Advantageously, but not limitatively, in this case ( i . e . when the conveyor assembly 6 is of the substantially continuous type ) , the conveyor assembly 6 is configured to move the layer of thickened powder S and the layer of compacted powder KP along the given path P at a speed ranging from circa 1 m per minute to circa 10 metres per minute . In addition, advantageously but not limitatively in this case , the compaction device 4 ( known in itsel f ) comprises : an upper compaction belt 13 , which is arranged above the transporter 9 at the compaction station 5 and cooperates with the transporter 9 to compact the layer of thickened powder S in a substantially continuous manner so as to obtain said layer of compacted powder KP . In this case , advantageously but not limitatively, the conveyor assembly also comprises an additional transporter 9 ' arranged downstream of the transporter 9 along the given path P to receive the layer of compacted powder KP and guide it to a cutting station 14 , as will be further explained below . Even more advantageously but not limitatively, between the transporter 9 and the subsequent transporter 9 ' there is an intermediate conveyor advantageous ly with rollers ( see Figure 2 ) .

According to alternative , advantageous but non-limiting embodiments , such as the one shown in Figure 1 , the compaction device 4 ( known in itsel f ) comprises : a lower compacting belt 12 in contact with the transporter 9 and an upper compacting belt 13 , which is arranged above the transporter 9 at the compaction station 5 and cooperates with the lower compacting belt 12 to compact the layer of thickened powder S in a substantially continuous manner so as to obtain said layer of compacted powder KP .

In this case , advantageously, the transporter 9 comprises ( in particular, is formed by) a conveyor belt that advantageously, but not limitatively, encloses therein this lower compaction belt 12 and extends from the input station 3 to the outlet from the compaction station 5 passing through the segment PA of the given path P . In this case , advantageously but not limitatively, this segment PA extends ( immediately) upstream of the compaction belts 12 and 13 along the given path P so that the powder ceramic material , in use , is firstly thickened by the vibrational action trans ferred at the segment PA and only then, once thickened, is compacted by the compaction device 4 ( as explained above ) .

Furthermore , according to still other non-limiting embodiments , which are particularly advantageous when a high thickness of powder ceramic material CP is to be processed without compromising the production speed (more speci fically, the moving speed of the transporter 9 ) , the manufacturing system 1 of ceramic articles T provides feeding the powder ceramic material CP via two di f ferent feeding devices 7 arranged in sequence along the given path P and thickening the powder ceramic material CP at two separate times . In this case , advantageously but not limitatively, the segment PA of the given path P comprises ( in particular, is subdivided into ) two parts T1 and T2 which are advantageously subsequent to each other without interruption along the moving direction A ( see Figure 2 ) and the feeding assembly 2 compri ses a first feeding device 7 configured to feed a first quantity of powder ceramic material CP in the area of the first part T1 of the segment PA, and a second feeding device 7 arranged downstream of the first feeding device 7 along the given path P and configured to feed a second quantity of powder ceramic material CP (on the first quantity of powder ceramic material CP that, in use, will be fed) in the area of the second part T2 of the segment PA, downstream of the first part T1 along the given path P (see Figure 2) . In this case, advantageously but not limitatively, the deaeration/cooling unit 8 comprises at least one further transmission element 11' , arranged downstream of the transmission element 11 along the given path P and in (advantageously mechanical) connection with the transporter 6 to transfer the vibrational action from the vibration generator 10 or 10' to the transporter 6. In detail (advantageously but not necessarily) , the transmission element 11' is arranged to transfer the vibrational action to the transporter 9 to the first part T1 of the segment PA so as to thicken, in use, the first quantity of powder ceramic material CP; and the further transmission element 11' is arranged to transfer the vibrational action to the transporter 9 to the second part T2 of the segment PA so as to thicken, in use, the second quantity of powder ceramic material CP fed on the first quantity.

According to alternative advantageous but non-limiting variants (such as the one shown in Figure 2) , the deaeration/ thickening unit 8 comprises the vibration generator 10 in connection with the transmission element 11 (e.g. as shown arranged immediately below the transmission element 11) and a further vibration generator 10' , similar to the previous one, arranged downstream along the given path P and immediately below the further transmission element 11' .

According to some advantageous but non-limiting embodiments such as those herein shown (see, for example, Figures 1 and 2) , the manufacturing system 1 of ceramic articles T comprises at least one cutting station 14 arranged downstream of the compaction station 5, along the given path P, wherein a cutting device 15 (known in itself and not further described herein) cuts the layer of compacted ceramic powder KP to obtain a plurality of base ceramic articles BC, which will then be fired in a firing kiln (not shown) , as mentioned above , to obtain the final ceramic articles T .

According to other advantageous but non-limiting embodiments ( such as the one schematically shown in Figure 3 ) , the manufacturing system 1 of ceramic articles T is of the discontinuous type . In this case , advantageously but not limitatively, the compaction device 4 is a press of the discontinuous type and comprises , in turn, a die 16 , a drive unit (not shown) to operate the die 16 and impart , in use , a defined compaction pressure to the layer of thickened powder S . In detail , advantageously but not limitatively, the die 16 comprises , in turn, a lower hal f-die 17 and an upper hal f-die (not visible in Figure 3 ) arranged facing and mutually movable closer to and away from each other, in particular along a vertical direction, to define between them a compaction chamber 18 intended to receive the layer of thickened powder S to be compacted .

According to some advantageous but non-limiting embodiments ( such as the one shown in Figure 3 ) , the transporter 9 is a movable distribution grid between a loading position C, at which it receives a given quantity of powder ceramic material CP, and a release position R, at which it releases the given quantity of powder ceramic material CP into the compaction chamber 18 . In detail , advantageously but not limitatively, the transporter 9 also comprises ( in particular, is formed by) a carriage , that may be operated by the aforementioned drive unit , to move the distribution grid between the loading position C and the release position R ( see Figure 3 wherein the distribution grid in the release position R is shown in dashed lines ) and the feeding device 7 comprises ( in particular, is formed by) a hopper with an adj ustable discharge opening to adj ust the quantity of powder ceramic material CP to be fed on the transporter 9 , in particular within the distribution grid . Advantageously but not limitatively, in this case , the transporter 9 ( in particular, the above-mentioned carriage ) is configured to move the distribution grid between the loading position C and the release position R at a speed ranging from circa 5 metres per minute to circa 150 metres per minute ( in particular, to circa 120 metres per minute ) . Advantageously but not limitatively, the segment PA of the given path P extends at said loading position C . Even more in particular, in this case , the transmission element 11 of the deaeration/ thickening unit 8 comprises a sliding plate arranged at said loading position C below the transporter 9 to trans fer the above-described vibrational action to the given quantity of powder ceramic material CP which is loaded into the distribution grid to thicken it and obtain the layer of thickened powder S .

In detail , in this case advantageously but not limitatively, the layer of compacted powder KP coincides with a basic ceramic article CB, as the distribution grid is loaded by the feeding device 7 with a dosed quantity of powder ceramic material CP, which is such that it forms a base ceramic article CB, once it has been thickened and compacted .

Furthermore , advantageously but not limitatively, in this case , the compaction device 4 also comprises an ej ection device ( known in itsel f and not shown or further described herein) which may be operated by the drive unit , to ej ect the layer of compacted powder KP ( in particular, the base ceramic article CB ) from the compaction station 5 to the outlet along the given path P .

According to another aspect of the present invention, a manufacturing process of ceramic articles T is proposed, which provides a feeding step, during which a feeding assembly 2 ( advantageously but not limitatively of the type described above in relation to the manufacturing system 1 of ceramic articles T ) feeds powder ceramic material CP to an input station 3 ; a compaction step, during which a compaction device 4 ( advantageously but not limitatively of the type described above in relation to the manufacturing system 1 of ceramic articles T ) is operated to obtain a layer of compacted powder KP, compacting a layer of thickened powder S as will be explained below; and a conveying step, during which a conveying unit 6 ( advantageously but not limitatively of the type described above in relation to the manufacturing system 1 of ceramic articles T ) transports the powder ceramic material CP along the aforementioned given path P in the aforementioned moving direction A from the input station 3 to the compaction station 5 and the layer of compacted powder KP along the given path P at least at the outlet of the compaction station .

Advantageously, the manufacturing process of ceramic articles T also comprises a deaeration step ( i . e . a thickening step ) , ( at least partially) preceding the compaction step and ( at least partially) following the feeding step, during which a deaeration/ thickening unit 8 , which is arranged upstream of the compaction device ( 4 ) along said given path ( P ) , transmits a vibrational action to the powder ceramic material CP so as to obtain a layer of thickened powder S , which is compacted during the compaction step, when the compaction device 4 compacts the layer of thickened powder S to obtain said layer of compacted powder KP .

Advantageously, but not limitatively, during this deaeration/ thickening step, the deaeration/ thickening unit 8 transmits the aforementioned vibrational action for a period ranging from at least circa 3 seconds to circa 20 seconds ( in particular, for a period ranging from circa 5 seconds to circa 15 seconds ; even more particularly, for a period of circa 12 seconds ) .

Advantageously, but not limitatively, during the conveying step, a transporter 9 ( advantageously of the type described above ) moves the powder ceramic material CP through a segment PA o f said given path P ; which, as already mentioned above in relation to the manufacturing system 1 of ceramic articles T , extends ( immediately) upstream of the compaction station 5 and has an extension ranging from at least circa 0 . 5 m to at least circa 2 m, in particular from circa 1 m to circa 1 . 5 m .

According to certain advantageous but non-limiting embodiments , the deaeration ( i . e . thickening) step comprises a vibration generation sub-step, during which the aforementioned vibrational action is generated ( advantageously but not limitatively by means of a vibration generator 10 made according to one of the embodiments described above ) , and a trans fer sub-step, during which a transmission element 11 ( advantageously but not limitatively of the type described above ) in connection ( advantageously mechanically) with the conveyor assembly 6 , in particular with the transporter 9 , trans fers the vibrational action to the conveyor assembly 6 , in particular to the transporter 9 , to the segment PA to thicken the powder ceramic material CP which, in use , is located and moves to said segment PA.

As regards the vibrational action, the considerations set out above in relation to the manufacturing system 1 of ceramic articles T remain valid . In detail , advantageously but not limitatively, this vibrational action has a vibration frequency ranging from circa 1 Hz to circa 1000 Hz ; in particular, from circa 10 Hz to circa 200 Hz .

According to some embodiments such as those schematically shown in Figures 1 and 2 , during the conveying step, the conveyor assembly 6 transports the powder ceramic material CP, the layer of thickened powder S , and the layer of compacted powder KP along the given path P in a substantially continuous manner ; in this case , the compaction step and the deaeration/ thickening step are ( at least partially) simultaneous with the conveying step . Furthermore , advantageously but not limitatively, during the compaction step, which is ( at least partially) subsequent to the thickening step, the layer of thickened powder S is compacted by a continuous compaction device 4 , which advantageously but not limitatively is implemented as described above in relation to the manufacturing system 1 of ceramic articles T . In particular, advantageously but not limitatively, with particular reference to Figure 2 , the continuous compaction device 4 comprises at least one upper compacting belt 13 , arranged above the transporter 9 , and during the compaction step, the transporter 9 and the upper compacting belt 13 cooperate to compact the layer of thickened powder S in a substantially continuous manner so as to obtain the layer of compacted powder KP .

Alternatively, advantageously but not limitatively with particular reference to Figure 1 , the continuous compaction device 4 comprises at least a lower compacting belt 12 arranged below in contact with the transporter 9 and an upper compacting belt 13 arranged above the transporter 9 , and during the compaction step, the lower compacting belt 12 and the upper compacting belt 13 cooperate to compact the layer of thickened powder S in a substantially continuous manner so as to obtain the layer of compacted powder KP .

Furthermore , as already mentioned in relation to the system 1 , according to some advantageous but not exclusive variants , the feeding step provides for a first feeding substep, during which a first feeding device 7 feeds a first quantity of powder ceramic material CP to an area of a first part T1 of said segment PA and a second feeding sub-step ( at least partially) subsequent to the first feeding step, during which a second feeding device 7 arranged downstream of the first feeding device 7 along the given path P, feeds ( on the first quantity of already thickened powder ceramic material CP ) a second quantity of powder ceramic material CP to an area of a second part T2 of the segment PA, downstream of the first part Tl . In this case , in fact , the deaeration/ thickening step comprises a first deaeration ( i . e . thickening) sub-step, which is ( at least partially) subsequent to the first feeding step and ( at least partially) prior to the second feeding step, during which the first quantity of powder material CP is thickened, and a second deaeration (i.e. thickening) sub-step, which is (at least partially) subsequent to the first deaeration (i.e. thickening) sub-step and the second feeding sub-step, during which the second quantity of powder material CP is thickened.

According to still other advantageous but non-limiting embodiments (such as the one shown in Figure 3) , the conveying step comprises a first transport sub-step, during which the transporter 9, which in this case comprises (in particular, is formed by) a movable distribution grid, receives a given quantity of powder ceramic material CP, at a loading position C, and transports it along the aforementioned segment PA to a release position R. Advantageously but not limitatively, the deaeration (i.e. thickening) step is (at least partially) simultaneous with the first transport sub-step; more particularly (advantageously but not necessarily) , the deaeration (i.e. thickening) step occurs while the transporter 9 is at the loading position C.

Advantageously but not limitatively, during the compaction step, the layer of thickened powder S is compacted in a discontinuous die 16 (advantageously but not limitatively, of the type described above, i.e. having at least one lower half-die 17 and a second, not shown upper half-die arranged facing each other and mutually movable closer to and away from each other) to compact the layer of thickened powder S and obtain the layer of compacted powder KP, in particular a base ceramic article CB as explained above in relation to the manufacturing system 1 of ceramic articles T.

The manufacturing process and system 1 of ceramic articles T of the present invention have several advantages, including the following.

Thanks to the deaeration/ thickening unit, at least part (in particular, most) of the air present between the grains of the ceramic powder material CP is evacuated before the powder material CP is subjected to the pressure necessary to be compacted. This makes it possible to settle the particles (i.e. grains) of powder ceramic material CP, facilitating and speeding up the subsequent compacting action, resulting in an advantageous increase in compaction efficiency, considered as the maximum compaction ratio that can be achieved as a function of the final density of the ceramic article T.

In fact, after the deaeration (i.e. thickening) step, therefore after the deaeration/ thickening action by means of the deaeration (i.e. thickening) unit 8, a reduction of at least circa 8% (in particular, from 8% to circa 20%) in the thickness of the powder ceramic material CP fed by the feeding assembly 2 was surprisingly observed, which facilitated compaction.

The result is an increase in the production speed for the same thickness of powder ceramic material CP to be compacted or an increase in the thickness of powder ceramic material CP to be compacted for the same production speed.

Claims

1. A manufacturing system (1) of ceramic articles (T) , in particular ceramic slabs or tiles; the manufacturing system (1) comprises: at least one feeding assembly (2) to feed powder ceramic material (CP) to an input station (3) ; a compaction device (4) , which is arranged at a compaction station (5) in order to obtain a layer of compacted powder (KP) ; a conveyor assembly (6) , which is configured to transport said powder ceramic material (CP) along a given path (P) in a moving direction (A) from said input station (3) to said compaction station (5) and the layer of compacted powder (KP) along said given path (P) at least out of said compaction station (5) ; the manufacturing system (1) of ceramic articles (T) is characterised in that it comprises a deaeration unit (8) , which is arranged upstream of the compaction device (4) along said given path (P) and is configured to transmit a vibrational action having at least a sussultatory component to said powder ceramic material (CP) , which, in use, is arranged at a segment (PA) of said given path (P) , so as to thicken said powder ceramic material (CP) and obtain a layer of thickened powder (S) ; said segment (PA) extending upstream of said compaction station (5) and having a length ranging from at least circa 0.5 m to at least circa 2 m; and said compaction device (4) being configured to transmit a compaction pressure to said layer of thickened powder (S) in order to obtain said layer of compacted powder (KP) .

2. The manufacturing system (1) of ceramic articles (T) according to claim 1, wherein said vibrational action has a vibration frequency ranging from circa 1 Hz (in particular, from circa 10 Hz) to circa 1000 Hz (in particular, to circa 200 Hz) .

3. The manufacturing system (1) of ceramic articles (T) according to any one of the preceding claims, wherein said conveyor assembly (6) is configured to move said powder ceramic material (CP) at least in the area of said segment (PA) of said given path (P) with a moving speed ranging from circa 1 metre per minute (in particular, from circa 5 metres per minute) to circa 150 metres per minute (in particular, to circa 120 metres per minute) .

4. The manufacturing system (1) of ceramic articles (T) according to any one of the preceding claims, wherein: the conveyor assembly (6) comprises at least one transporter (9) , which extends from said input station (3) to at least said compaction station (5) going through said segment (PA) of said given path (P) ; and said deaeration unit (8) comprises at least one vibration generator (10) to generate said vibrational action and at least one transmission element (11) in connection to said transporter (9) to transfer said vibrational action from said vibration generator (10) to said transporter (9) at said segment (PA) of said given path (P) .

5. The manufacturing system (1) of ceramic articles (T) according to claim 4, wherein said transmission element (11) comprises (in particular, is) a plate arranged under and in contact with said transporter (9) , which plate has a length ranging from at least circa 0.5m to at least circa 2m.

6. The manufacturing system (1) of ceramic articles (T) according to claim 4 or 5, wherein: said conveyor assembly (6) is configured to transport the powder ceramic material (CP) , said layer of thickened powder (S) and said layer of compacted powder (KP) along said given path (P) in a substantially continuous manner; said compaction device (4) comprises a compacting belt (13) , which is arranged above said transporter (9) at said compaction station (5) and cooperates at least with said first transporter (9) in order to compact said layer of thickened powder (S) in a substantially continuous manner so as to obtain said layer of compacted powder (KP) ; said transporter (9) comprises (in particular, consists of) a conveyor belt; in particular, said segment (PA) of the given path (P) extends upstream of said compacting belt (13) along said given path (P) .

7. The manufacturing system (1) of ceramic articles (T) according to claim 6, wherein: the feeding assembly (2) comprises at least a first feeding device (7) , which is configured to feed a first quantity of powder ceramic material (CP) at a first part (Tl) of said segment (PA) , and a second feeding device (7) , which is arranged downstream of the first feeding device (7) along said given path (P) and is configured to feed a second quantity of powder ceramic material (CP) at a second part (T2) of said segment (PA) , downstream of said first part (Tl) along said given path (P) ; said deaeration unit (8) comprises at least one further transmission element arranged downstream of said at least one transmission element (11) along said given path (P) and in connection to said transporter (9) to transfer said vibrational action from said vibration generator (10) to said first transporter (9) ; said at least one transmission element (11) being arranged so as to transfer said vibrational action to said transporter (9) at said first part (Tl) of said segment (PA) so as to thicken, in use, said first quantity of powder ceramic material (CP) ; and said further transmission element (11) being arranged so as to transfer said vibrational action to said transporter (9) at said second part (T2) of said segment (PA) so as to thicken, in use, said second defined quantity of powder ceramic material (CP) .

8. The system (1) to manufacture ceramic articles (T) according to any one of the claims from 1 to 5, wherein: said compaction device (4) comprises a die (16) , which comprises, in turn, a compaction chamber (18) and is configured to apply a defined compaction pressure to said layer of thickened ceramic powder (S) so as to obtain a layer of compacted powder (KP) (in particular, a base ceramic article (CB) ) ; said transporter (9) is a distribution grid, which is movable between a loading position (C) , in which it receives a given quantity of powder ceramic material (CP) , and a release position (R) , in which it releases the given quantity of powder ceramic material (CP) into said compaction chamber (18) ; and said segment (PA) of the said given path (P) extends in the area of said loading position (C) ; in particular, said transmission element (11) of said deaeration unit (8) comprises a sliding plate arranged in the area of said loading position (C) under said transporter (9) so as to transfer said vibrational action to said given quantity of powder ceramic material (CP) , which, in use, is loaded on said distribution grid (9) , in order to thicken it .

9. A process to manufacture ceramic articles (T) , in particular ceramic slabs or tiles, comprising: a feeding step, during which a feeding assembly (2) feeds powder ceramic material (CP) to an input station (3) ; a compaction step, during which a compaction device (4) , which is arranged at a compaction station (5) , is operated so as to obtain a layer of compacted powder (KP) ; and a conveying step, during which a conveyor assembly (6) transports said powder ceramic material (CP) along a given path (P) in a moving direction (A) from said input station (3) up to said compaction station (5) and the layer of compacted powder (KP) along said given path (P) at least out of said compaction station (5) ; the process to manufacture ceramic articles (T) being characterized in that it comprises a deaeration step, at least partially prior to said compaction step and at least partially subsequent to said feeding step, during which a deaeration unit (8) , which is arranged upstream of the compaction device (4) along said given path (P) , transmits a vibrational action having at least a sussultatory component to said powder ceramic material (CP) so as to obtain a layer of thickened powder (S) ; and in that, during said compaction step, a compaction device (4) compacts said layer of thickened powder (S) in order to obtain said layer of compacted powder (KP) .

10. The process to manufacture ceramic articles (T) according to claim 9, wherein: during said deaeration step, the deaeration unit (8) transmits said vibrational action to said powder ceramic material (CP) for an amount of time ranging from at least circa 3 seconds to circa 20 seconds (in particular, for an amount of time ranging from circa 5 seconds to circa 15 seconds; more in particular, for an amount of time of circa 12 seconds) .

11. The process to manufacture ceramic articles (T) according to claim 9 or 10, wherein: during said conveying step, a transporter (9) moves said powder ceramic material (CP) through a segment (PA) of said given path (P) ; and said deaeration step includes a vibration generation sub-step, during which said vibrational action is generated, and a transfer sub-step, during which a transmission element (11) in connection to said conveyor assembly transfers said vibrational action to said conveyor assembly (6) in the area of said segment (PA) of said given path (P) so as to thicken the powder ceramic material (CP) , which, in use, is arranged in the area of said segment (PA) ; in particular, said vibrational action having a vibration frequency ranging from circa 1 Hz (in particular, from circa 10 Hz) to circa 1000 Hz (in particular, to circa 200 Hz) .

12. The process to manufacture ceramic articles (T) according to claim 9, 10 or 11, wherein: during said conveying step, said conveyor assembly (6) transports the powder ceramic material (CP) layer of thickened powder (S) and said layer of compacted powder (KP) along said given path (P) in a substantially continuous manner; said compaction step and said deaeration step are at least partially simultaneous with said conveying step; said compaction step is at least partially subsequent to said deaeration step and, during said compaction step, said transporter (9) and at least one compacting belt (13) , which is arranged above said transporter (9) , cooperate in order to compact said layer of thickened powder (S) in a substantially continuous manner so as to obtain said layer of compacted powder (KP) .

13. The process to manufacture ceramic articles (T) according to claim 12, wherein: said feeding step includes a first feeding sub-step, during which a first feeding device (7) feeds a first quantity of powder ceramic material (CP) at a first part (Tl) of said segment (PA) , and a second feeding sub-step, at least partially subsequent to the first feeding sub-step, during which a second feeding device (7) , which is arranged downstream of the first feeding device (7) along said given path (P) , feeds a second quantity of powder ceramic material (CP) at a second part (T2) of said segment (PA) , downstream of said first part (Tl) along said given path (P) ; said deaeration step comprises a first deaeration substep, during which said first quantity of powder material (CP) is thickened, and a second deaeration sub-step, at least partially subsequent to said first deaeration sub-step, during which said second quantity of powder material (CP) is thickened .

14. The process to manufacture ceramic articles (T) according to claim 11, wherein: the conveying step includes a first transport sub-step, during which said transporter (9) , which comprises (in particular, consists of ) a movable distribution grid, receives a given quantity of powder ceramic material ( CP ) at a loading position and transports it along said segment ( PA) up to a release position; said deaeration step is at least partially simultaneous with said first transport sub-step ; and during said compaction step, which is at least partially subsequent to said deaeration step, a die ( 16 ) applies a defined compaction pressure to said layer ( S ) of thickened powder so as to obtain a layer of compacted powder (KP ) .