Plant for the production of ceramic products

Abstract

A plant (1) for the production of ceramic products (CP) comprises: a forming station (5, 7) to obtain a number of slabs (BCS) of compacted ceramic powder provided with a surface (S) to be decorated; a kiln (17); and a decoration station (12) arranged between the forming station and the kiln and provided with a first application assembly (15) for applying a first layer on a portion of the surface (S) and an electrostatic application unit (22) arranged downstream of the first application assembly (15) and configured to apply, on the first layer, a second layer of a powder covering material. The electrostatic application unit (22) comprises: a tank (23) which holds the powder covering material fluidized with air; dispensing devices (27) facing the surface (S) of the slabs (BCS); and a pumping member (25) drawing powder covering material fluidized with air from the tank (23) and feeding it to the dispensing devices (27).

Description

[0001] "PLANT FOR THE PRODUCTION OF CERAMIC PRODUCTS"

[0002] CROSS-REFERENCE TO RELATED APPLICATIONS

[0003] This Patent Application claims priority from Italian Patent Application No . 102024000012841 filed on June 5 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0004] FIELD OF THE ART

[0005] The present invention further relates to a plant for the production of ceramic products .

[0006] PRIOR ART

[0007] In the field of the production of ceramic products , in particular of large ceramic slabs , i . e . of the type having at least one side with a length equal to or greater than 100 ( one hundred) centimetres , plants of known type usually comprise a conveyor assembly which substantially continuously feeds a layer of ceramic powder material from an input station towards a station comprising a compaction machine . Downstream of the compaction machine there is provided a cutting station to obtain a number of slabs of compacted ceramic powder ( i . e . a number of base or "raw" ceramic slabs ) .

[0008] The base ceramic slabs exiting the cutting station are then fed to a decoration system comprising a drier which is configured to heat the base ceramic slabs up to a temperature of at least circa 100 ° C and a glazing station, arranged immediately downstream of the drier and comprising an airless booth to apply an even layer of liquid glaze so as to even out the surface to be decorated of the dried base ceramic slabs . The ceramic base slabs exiting the glazing station are then supplied to a number of decoration stations comprising respective printing, alternatively digital or inkj et assemblies , to apply decoration layers on the layer of liquid enamel so as to reproduce a predetermined decoration design or pattern on the surface to be decorated . Finally, the plant comprises a kiln arranged downstream of the decoration stations to sinter the base ceramic slabs so as to obtain the finished ceramic slabs .

[0009] Documents US2010129542 , WO2018015978 , EP1020266 , and ITUB20160734 describe respective plants for the production of ceramic products of known type ; US2016075149 describes instead an electrostatic application station .

[0010] Although the plants of the type known for the production of ceramic products work satis factorily, there is still a need to improve them further, in particular with regard to the decoration systems .

[0011] DISCLOSURE OF THE INVENTION

[0012] Aim of the present invention is therefore to provide a plant for the production of ceramic products , which plant is free of the drawbacks of the state of the art and i s at the same time easy and economical to manufacture .

[0013] In accordance with the present invention there is provided a plant for the production of ceramic products as claimed in the appended claims . The claims describe preferred embodiments of the present invention forming an integral part of the present disclosure .

[0014] BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The invention wi ll now be described with reference to the accompanying drawings , which show some non-limiting examples of embodiments , in which :

[0016] Figure 1 is a side and schematic view of a first embodiment of a plant for the production of ceramic products made in accordance with the present invention;

[0017] Figure 2 is a side and schematic view of a second embodiment of a plant for the production of ceramic products made in accordance with the present invention;

[0018] Figure 3 is a side and schematic view of a third embodiment of a plant for the production of ceramic products made in accordance with the present invention;

[0019] Figure 4 is a side and schematic view of a fourth embodiment of a plant for the production of ceramic products made in accordance with the present invention .

[0020] Figure 5 is a perspective view of an electrostatic application station of the plant for the production of ceramic products of Figures 1 to 4 .

[0021] PREFERRED EMBODIMENTS OF THE INVENTION

[0022] In Figure 1 , number 1 denotes as a whole a plant for the manufacture of ceramic products , in particular a ceramic slab CP .

[0023] The plant 1 comprises a conveyor assembly 2 comprising a belt conveyor 3 to feed ( substantially continuously) a layer LPM of ceramic powder material along a path P in a moving direction A from an input station 4 towards a processing station 5 .

[0024] The conveyor assembly 2 is configured to substantially continuously trans fer the layer LPM of ceramic powder material . The conveyor assembly 2 is preferably made in an initial segment by means of a belt conveyor 3 wrapped in a closed ring around rollers 35 . Advantageously, the belt conveyor 3 is made of metal material , in particular steel .

[0025] The input station 4 comprises a powder material feeding assembly 18 arranged upstream of the processing station 5 . The feeding assembly 18 comprises a feeding device for feeding a mixture of ceramic powders ( in particular, arranged above the conveyor assembly 2 ) for the creation of the layer LPM of ceramic powder material on the belt conveyor 3 .

[0026] The belt conveyor 3 is configured to convey the layer LPM of ceramic powder material from the input station 4 to the processing station 5 along the path P . In other words , the processing station 5 is arranged downstream of the input station 4 along the path P .

[0027] The processing station 5 comprises a pressing unit 6 configured to compact the layer LPM of ceramic powder material , so as to obtain a continuous strip SPM of compacted ceramic powder .

[0028] In the pressing unit 6 the belt conveyor 3 acts as a lower compactor belt . The pressing unit 6 then comprises an upper compactor belt 36 which cooperates with the belt conveyor 3 to dry compact the layer LPM of ceramic powder material and obtain the continuous strip SPM of compacted ceramic powder . The upper compactor belt 36 is preferably at least partially inclined with respect to the belt conveyor 3 towards which it converges in the moving direction A to gradually increase the pressure on the layer LPM of ceramic powder material . Advantageously, the upper compactor belt 36 is wound around a front motor roller 39 and a rear driven roller 40 .

[0029] Furthermore , both the belt conveyor 3 and the upper compactor belt 36 are provided with respective compacting rollers ( or roller assemblies ) indicated respectively with 37 and 38 arranged in a central area .

[0030] The conveyor assembly 2 is then preferably made in an intermediate segment by means of a belt conveyor 90 wrapped in a closed ring around rollers . The belt conveyor 90 is arranged along the path P downstream of the conveyor belt 3 to which it is connected by means of a roller conveyor 91 . The plant 1 then comprises a cutting station 7 arranged along the path P, downstream of the processing station 5 . The cutting station 7 i s arranged in the area o f the belt conveyor 90 . The cutting station 7 is intended to cut transversely to the moving direction A the continuous strip SPM of compacted ceramic powder so as to obtain a number of slabs BCS of compacted ceramic powder ( i . e . a number of basic or "raw" ceramic slabs BCS ) .

[0031] Each slab BCS o f compacted ceramic powder is provided with a surface S to be decorated, defined by the surface that is intended, in use , to be visible ( i . e . exposed) . Preferably, the surface S to be decorated is the surface facing upwards while conveying by means of the conveyor assembly 2 . In other words , again, the surface S to be decorated is substantially parallel to the conveying plane defined by the conveyor assembly 2 , but is not in direct contact with the conveying plane while moving along the path P .

[0032] The conveyor as sembly 2 then comprises a conveying device 8 , of the belt or roller type , which receives the base ceramic slabs BCS exiting the cutting station 7 . The conveying device 8 is configured to convey the base ceramic slabs BCS along a final segment of the path, downstream of the intermediate segment . The conveying device 8 is made of metal material , or plastic material with dispersed metal fibres .

[0033] The plant 1 comprises a drier 14 arranged along the final segment of the path P, downstream of the cutting station 7 . The drier 14 is configured to heat the base ceramic slabs BCS up to a temperature of at least about 100 ° C ( in particular, at least about 150 ° C ) .

[0034] The conveying device 8 is then configured to convey the base ceramic slabs BCS through a decoration system 9 along the path P for the decoration of the base ceramic slabs BCS ; in particular, through at least one decoration station 12 . The decoration station 12 is arranged along the path P downstream of the drier 14 .

[0035] Finally, the plant 1 comprises a kiln 17 arranged along the path P downstream of the decoration station 12 to sinter the base ceramic slabs BCS so as to obtain the finished ceramic slabs CP . In particular, the kiln 17 is configured to impose a temperature ranging from at least about 1000 ° C to at least about 1300 ° C .

[0036] Advantageously, the decoration system 9 may comprise further decoration stations and / or further electrostatic application stations . According to an advantageous but nonlimiting embodiment , the decoration system 9 comprises a further decoration station 28 arranged along the path P downstream of the kiln 17 . For example , the decoration station 28 is an electrostatic application station 28 . The electrostatic application station 28 is made to apply a final layer comprising a powder covering material . Advantageously, the covering material of the final layer can be any powder material , for example a fixing material , or a material such as to provide the surface S to be decorated with particular aesthetic properties ( for example particular shine ) and / or functional properties ( for example particular roughness ) .

[0037] The decoration station 12 comprises a printing assembly 15 to apply a layer on the surface S to be decorated of each base ceramic slab BCS . Preferably, the printing assembly 15 comprises a digital deposition assembly configured to digitally apply the layer so as to reproduce a design or pattern of predetermined decoration defined on the surface S to be decorated . In other words , the printing assembly 15 is made so that the applied layer defines a design or decoration on the surface S to be decorated .

[0038] The decoration station 12 further comprises an electrostatic application unit 22 . The electrostatic application unit 22 is configured to apply on the surface S to be decorated a layer consisting of a covering material , in particular powder .

[0039] According to a possible embodiment , the decoration station 12 then comprises a printing assembly 21 configured to apply a layer of a precursor material (or primer ) on the surface S to be decorated . The printing assembly 21 is arranged along the path P immediately upstream of the printing assembly 15 . According to a first embodiment , the printing assembly 21 comprises a digital deposition member configured to digitally apply the layer of precursor material in an even manner over the entire surface S to be decorated .

[0040] Alternatively, the printing assembly 21 is arranged along the path P immediately downstream of the printing assembly 15 ( i . e . interposed between the printing assembly 15 and the electrostatic application unit 22 ) .

[0041] Alternatively, the printing assembly 21 comprises a digital deposition member configured to digitally apply the layer of precursor material only partially onto the surface S to be decorated . The digital deposition member is configured to apply the layer exclusively on a portion of the surface S to be decorated .

[0042] In Figure 2 , number 1 denotes as a whole a second embodiment of the plant for the manufacture of a ceramic slab CP .

[0043] The plant 1 comprises a conveyor assembly 2 comprising a belt conveyor 3 to feed ( substantially continuously) a layer LPM of ceramic powder material along a path P in a moving direction A from an input station 4 towards a processing station 5 .

[0044] The conveyor assembly 2 is configured to substantially continuously trans fer the layer LPM of ceramic powder material . The conveyor assembly 2 is preferably made in an initial segment by means of a belt conveyor 3 wrapped in a closed ring around rollers 35 . Advantageously, the belt conveyor 3 is made of metal material , in particular steel .

[0045] The input station 4 comprises a powder material feeding assembly 18 arranged upstream of the processing station 5 . The feeding assembly 18 comprises a feeding device for feeding a mixture of ceramic powders ( in particular, arranged above the conveyor assembly 2 ) for the creation of the layer LPM of ceramic powder material on the belt conveyor 3 .

[0046] The belt conveyor 3 is configured to convey the layer LPM of ceramic powder material from the input station 4 to the processing station 5 along the path P . In other words , the processing station 5 is arranged downstream of the input station 4 along the path P .

[0047] The processing station 5 comprises a pressing unit 6 configured to compact the layer LPM of ceramic powder material , so as to obtain a continuous strip SPM of compacted ceramic powder .

[0048] In the pressing unit 6 the belt conveyor 3 acts as a lower compactor belt . The pressing unit 6 then comprises an upper compactor belt 36 which cooperates with the belt conveyor 3 to dry compact the layer LPM of ceramic powder material and obtain the continuous strip SPM of compacted ceramic powder . The upper compactor belt 36 is preferably at least partially inclined with respect to the belt conveyor 3 towards which it converges in the moving direction A to gradually increase the pressure on the layer LPM of ceramic powder material . Advantageously, the upper compactor belt 36 is wound around a front motor roller 39 and a rear driven roller 40 .

[0049] Furthermore , both the belt conveyor 3 and the upper compactor belt 36 are provided with respective compacting rollers ( or roller assemblies ) indicated respectively with 37 and 38 arranged in a central area .

[0050] The conveyor assembly 2 is then preferably made in an intermediate segment by means of a belt conveyor 90 wrapped in a closed ring around rollers . The belt conveyor 90 is arranged along the path P downstream of the conveyor belt 3 to which it is connected by means of a roller conveyor 91 . The plant 1 then comprises a cutting station 7 arranged along the path P, downstream of the processing station 5 . The cutting station 7 i s arranged in the area o f the belt conveyor 90 . The cutting station 7 is intended to cut transversely to the moving direction A the continuous strip SPM of compacted ceramic powder so as to obtain a number of slabs BCS of compacted ceramic powder ( i . e . a number of basic or "raw" ceramic slabs BCS ) .

[0051] Each slab BCS o f compacted ceramic powder is provided with a surface S to be decorated, defined by the surface that is intended, in use , to be visible ( i . e . exposed) . Preferably, the surface S to be decorated is the surface facing upwards while conveying by means of the conveyor assembly 2 . In other words , again, the surface S to be decorated is substantially parallel to the conveying plane defined by the conveyor assembly 2 , but is not in direct contact with the conveying plane while moving along the path P .

[0052] The conveyor as sembly 2 then comprises a conveying device 8 , of the belt or roller type , which receives the base ceramic slabs BCS exiting the cutting station 7 . The conveying device 8 is made of metal material , or plastic material with dispersed metal fibres . The conveying device 8 is configured to convey the base ceramic slabs BCS along a final segment o f the path, downstream of the intermediate segment .

[0053] The plant 1 comprises a decoration system 9 having at least one decoration station 12 arranged along the final segment of the path P, downstream of the cutting station 7 . The conveying device 8 is then configured to convey the base ceramic slabs BCS through the decoration system 9 along the path P for the decoration of the base ceramic slabs BCS . The decoration station 12 is arranged along the path P downstream of the cutting station 7 .

[0054] The plant 1 comprises a drier 14 arranged along the final segment of the path P, downstream of the decoration station 12 . The drier 14 is configured to heat the base ceramic slabs BCS up to a temperature of at least about 100 ° C ( in particular, at least about 150 ° C ) .

[0055] Finally, the plant 1 comprises a kiln 17 arranged along the path P downstream of the drier 14 to sinter the base ceramic slabs BCS so as to obtain the finished ceramic slabs CP . In particular, the kiln 17 is configured to impose a temperature ranging from at least about 1000 ° C to at least about 1300 ° C .

[0056] Advantageously, the decoration system 9 may comprise further decoration stations and / or further electrostatic application stations . According to an advantageous but nonlimiting embodiment , the decoration system 9 comprises a further decoration station 52 arranged along the path P downstream of the drier 14 ( in particular, the decoration station 52 is interposed between the drier 14 and the kiln 17 ) . The decoration station 52 comprises a printing assembly 53 to apply a layer at least partially on the surface S to be decorated . Preferably, the printing assembly 53 comprises a digital deposition assembly conf igured to digital ly apply the layer so as to reproduce a predetermined pattern of decoration on the surface S to be decorated . Furthermore , the decoration system 9 compri ses a further decoration station 28 arranged along the path P downstream of the kiln 17 . For example , the decoration station 28 is an electrostatic application station 28 . The electrostatic application station 28 is made to apply a final layer comprising a powder covering material . Advantageously, the covering material of the final layer can be any powder material , for example a fixing material , or a material such as to provide the surface S to be decorated with particular aesthetic properties ( for example particular shine ) and / or functional properties ( for example particular roughness ) .

[0057] The decoration station 12 comprises a printing assembly 15 to apply a layer on the surface S to be decorated of each base ceramic slab BCS . Preferably, the printing assembly 15 comprises a digital deposition assembly configured to digitally apply the layer so as to reproduce a design or pattern of predetermined decoration defined on the surface S to be decorated . In other words , the printing assembly 15 is made so that the applied layer defines a design or decoration on the surface S to be decorated .

[0058] The decoration station 12 further comprises an electrostatic application unit 22 . The electrostatic application unit 22 is configured to apply on the surface S to be decorated a layer consisting of a covering material , in particular powder .

[0059] According to a possible embodiment , the decoration station 12 then comprises a printing assembly 21 configured to apply a layer of a precursor material (or primer ) on the surface S to be decorated . The printing assembly 21 is arranged along the path P immediately upstream of the printing assembly 15 . According to a first embodiment , the printing assembly 21 comprises a digital deposition member configured to digitally apply the layer of precursor material in an even manner over the entire surface S to be decorated .

[0060] Alternatively, the printing assembly 21 is arranged along the path P immediately downstream of the printing assembly 15 ( i . e . interposed between the printing assembly 15 and the electrostatic application unit 22 ) .

[0061] Alternatively, the printing assembly 21 comprises a digital deposition member configured to digitally apply the layer of precursor material only partially onto the surface S to be decorated . The digital deposition member is configured to apply the layer exclusively on a portion of the surface S to be decorated .

[0062] A third embodiment of the plant for the reali zation of a ceramic slab CP is indicated as a whole in Figure 3 with number 1 .

[0063] The plant 1 comprises a conveyor assembly 2 comprising a belt conveyor 3 to feed ( substantially continuously) a layer LPM of ceramic powder material along a path P in a moving direction A from an input station 4 towards a processing station 5 . The conveyor assembly 2 is configured to substantially continuously trans fer the layer LPM of ceramic powder material .

[0064] The conveyor assembly 2 is preferably made in an initial segment by means of a belt conveyor 3 wrapped in a closed ring around rollers 35 . Advantageously, the belt conveyor 3 is made of metal material , in particular steel .

[0065] The input station 4 comprises a powder material feeding assembly 18 arranged upstream of the processing station 5 . The feeding assembly 18 comprises a feeding device for feeding a mixture of ceramic powders ( in particular, arranged above the conveyor assembly 2 ) for the creation of the layer LPM of ceramic powder material on the belt conveyor 3 .

[0066] The belt conveyor 3 is configured to convey the layer LPM of ceramic powder material from the input station 4 to the processing station 5 along the path P . In other words , the processing station 5 is arranged downstream of the input station 4 along the path P .

[0067] The processing station 5 comprises a pressing unit 6 configured to compact the layer LPM of ceramic powder material , so as to obtain a continuous strip SPM of compacted ceramic powder .

[0068] In the pressing unit 6 the belt conveyor 3 acts as a lower compactor belt . The pressing unit 6 then comprises an upper compactor belt 36 which cooperates with the belt conveyor 3 to dry compact the layer LPM of ceramic powder material and obtain the continuous strip SPM of compacted ceramic powder . The upper compactor belt 36 is preferably at least partially inclined with respect to the belt conveyor 3 towards which it converges in the moving direction A to gradually increase the pressure on the layer LPM of ceramic powder material . Advantageously, the upper compactor belt 36 is wound around a front motor roller 39 and a rear driven roller 40 .

[0069] Furthermore , both the belt conveyor 3 and the upper compactor belt 36 are provided with respective compacting rollers ( or roller assemblies ) indicated respectively with 37 and 38 arranged in a central area .

[0070] The conveyor assembly 2 is then preferably made in an intermediate segment by means of a belt conveyor 90 wrapped in a closed ring around rollers . The belt conveyor 90 is arranged along the path P downstream of the conveyor belt 3 to which it is connected by means of a roller conveyor 91 . The plant 1 then comprises a cutting station 7 arranged along the path P, downstream of the processing station 5 . The cutting station 7 is arranged in the area of the belt conveyor 90 . The cutting station 7 is intended to cut transversely to the moving direction A the continuous strip SPM of compacted ceramic powder so as to obtain a number of slabs BCS of compacted ceramic powder ( i . e . a number of basic or "raw" ceramic slabs BCS ) .

[0071] Each slab BCS o f compacted ceramic powder is provided with a surface S to be decorated, defined by the surface that is intended, in use , to be visible ( i . e . exposed) . Preferably, the surface S to be decorated is the surface facing upwards while conveying by means of the conveyor assembly 2 . In other words , again, the surface S to be decorated is substantially parallel to the conveying plane defined by the conveyor assembly 2 , but is not in direct contact with the conveying plane while moving along the path P .

[0072] The conveyor as sembly 2 then comprises a conveying device 8 , of the belt or roller type , which receives the base ceramic slabs BCS exiting the cutting station 7 . The conveying device 8 is made of metal material or plastic material with dispersed metal fibres . The conveying device 8 is configured to convey the base ceramic slabs BCS along a final segment o f the path, downstream of the intermediate segment .

[0073] The plant 1 comprises a decoration system 9 having at least one decoration station 12 arranged along the final segment of the path P, downstream of the cutting station 7 . The conveying device 8 is then configured to convey the base ceramic slabs BCS through the decoration system 9 along the path P for the decoration of the base ceramic slabs BCS .

[0074] The plant 1 comprises a drier 14 arranged along the final segment of the path P in the area of the decoration station 12 as better described in the following discussion . The drier 14 is configured to heat the base ceramic slabs BCS up to a temperature of at least about 100 ° C ( in particular, at least about 150 ° C ) .

[0075] Finally, the plant 1 comprises a kiln 17 arranged along the path P downstream of the drier 14 and of the decoration station 12 to sinter the base ceramic slabs BCS so as to obtain the finished ceramic slabs CP . In particular, the kiln 17 is configured to impose a temperature ranging from at least about 1000 ° C to at least about 1300 ° C .

[0076] Advantageously, the decoration system 9 may comprise further decoration stations and / or further electrostatic application stations . According to an advantageous but nonlimiting embodiment , the decoration system 9 comprises a further decoration station 52 arranged along the path P downstream of the drier 14 and the electrostatic application unit 22 ( in particular, the decoration station 52 is interposed between the electrostatic application unit 22 and the kiln 17 ) . The decoration station 52 comprises a printing assembly 53 to apply a layer at least partially on the surface S to be decorated . Preferably, the printing assembly 53 comprises a digital deposition assembly configured to digitally apply the layer so as to reproduce a predetermined pattern of decoration on the surface S to be decorated . Furthermore , the decoration system 9 comprises a further decoration station 28 arranged along the path P downstream of the kiln 17 . For example , the decoration station 28 is an electrostatic application station 28 . The electrostatic application station 28 is made to apply a final layer comprising a powder covering material . Advantageously, the covering material of the final layer can be any powder material , for example a fixing material , or a material such as to provide the surface S to be decorated with particular aesthetic properties ( for example particular shine ) and / or functional properties ( for example particular roughness ) .

[0077] The decoration station 12 comprises a printing assembly 15 to apply a layer on the surface S to be decorated of each base ceramic slab BCS . The printing assembly 15 is arranged along the final segment of the path P upstream of the drier 14 . Preferably, the printing assembly 15 comprises a digital deposition assembly configured to digitally apply the layer so as to reproduce a design or pattern of predetermined decoration defined on the surface S to be decorated . In other words , the printing assembly 15 is made so that the applied layer defines a design or decoration on the surface S to be decorated .

[0078] The decoration station 12 further comprises an electrostatic application unit 22 . The electrostatic application unit 22 is arranged along the final segment of the path P downstream of the drier 14 . The electrostatic application unit 22 is configured to apply on the surface S to be decorated a layer consisting of a covering material , in particular powder . In other words , the drier 14 is interposed between the printing assembly 15 and the electrostatic application unit 22 . In this case, the decoration station 12 is arranged along the path P partially upstream of the drier 14 (with the printing assembly 15 ) and partially downstream of the drier 14 (with the electrostatic application unit 22 ) .

[0079] According to a possible embodiment , the decoration station 12 then comprises a printing assembly 21 configured to apply a layer of a precursor material (or primer ) on the surface S to be decorated . The printing assembly 21 is arranged along the path P immediately upstream of the printing assembly 15 . According to a first embodiment , the printing assembly 21 comprises a digital deposition member configured to digitally apply the layer of precursor material in an even manner over the entire surface S to be decorated .

[0080] Alternatively, the printing assembly 21 is arranged along the path P immediately downstream of the printing assembly 15 ( i . e . interposed between the printing assembly 15 and the electrostatic application unit 22 ) .

[0081] Alternatively, the printing assembly 21 comprises a digital deposition member configured to digitally apply the layer of precursor material only partially onto the surface S to be decorated . The digital deposition member is configured to apply the layer exclusively on a portion of the surface S to be decorated .

[0082] In Figure 4 , number 1 denotes as a whole a fourth embodiment of the plant for the manufacture of a ceramic slab CP .

[0083] The plant 1 comprises a conveyor assembly 2 comprising a belt conveyor 3 to feed ( substantially continuously) a layer LPM of ceramic powder material along a path P in a moving direction A from an input station 4 towards a processing station 5 . The conveyor assembly 2 is configured to substantially continuously trans fer the layer LPM of ceramic powder material .

[0084] The conveyor assembly 2 is preferably made in an initial segment by means of a belt conveyor 3 wrapped in a closed ring around rollers 35 . Advantageously, the belt conveyor 3 is made of metal material , in particular steel .

[0085] The input station 4 comprises a powder material feeding assembly 18 arranged upstream of the processing station 5 . The feeding assembly 18 comprises a feeding device for feeding a mixture of ceramic powders ( in particular, arranged above the conveyor assembly 2 ) for the creation of the layer LPM of ceramic powder material on the belt conveyor 3 .

[0086] The belt conveyor 3 is configured to convey the layer LPM of ceramic powder material from the input station 4 to the processing station 5 along the path P . In other words , the processing station 5 is arranged downstream of the input station 4 along the path P .

[0087] The processing station 5 comprises a pressing unit 6 configured to compact the layer LPM of ceramic powder material , so as to obtain a continuous strip SPM of compacted ceramic powder .

[0088] In the pressing unit 6 the belt conveyor 3 acts as a lower compactor belt . The pressing unit 6 then comprises an upper compactor belt 36 which cooperates with the belt conveyor 3 to dry compact the layer LPM of ceramic powder material and obtain the continuous strip SPM of compacted ceramic powder . The upper compactor belt 36 is preferably at least partially inclined with respect to the belt conveyor 3 towards which it converges in the moving direction A to gradually increase the pressure on the layer LPM of ceramic powder material . Advantageously, the upper compactor belt 36 is wound around a front motor roller 39 and a rear driven roller 40 .

[0089] Furthermore , both the belt conveyor 3 and the upper compactor belt 36 are provided with respective compacting rollers ( or roller assemblies ) indicated respectively with 37 and 38 arranged in a central area .

[0090] The conveyor assembly 2 is then preferably made in an intermediate segment by means of a belt conveyor 90 wrapped in a closed ring around rollers . The belt conveyor 90 is arranged along the path P downstream of the conveyor belt 3 to which it is connected by means of a roller conveyor 91 . The plant 1 then comprises a cutting station 7 arranged along the path P, downstream of the processing station 5 . The cutting station 7 is arranged in the area of the belt conveyor 90 . The cutting station 7 is intended to cut transversely to the moving direction A the continuous strip SPM of compacted ceramic powder so as to obtain a number of slabs BCS of compacted ceramic powder ( i . e . a number of basic or "raw" ceramic slabs BCS ) .

[0091] Each slab BCS o f compacted ceramic powder is provided with a surface S to be decorated, defined by the surface that is intended, in use , to be visible ( i . e . exposed) . Preferably, the surface S to be decorated is the surface facing upwards while conveying by means of the conveyor assembly 2 . In other words , again, the surface S to be decorated is substantially parallel to the conveying plane defined by the conveyor assembly 2 , but is not in direct contact with the conveying plane while moving along the path P .

[0092] The conveyor as sembly 2 then comprises a conveying device 8 , of the belt or roller type , which receives the base ceramic slabs BCS exiting the cutting station 7 . The conveying device 8 is made of metal material or plastic material with dispersed metal fibres . The conveying device 8 is configured to convey the base ceramic slabs BCS along a final segment o f the path, downstream of the intermediate segment .

[0093] The plant 1 comprises a decoration system 9 having at least one decoration station 12 arranged along the final segment of the path P, downstream of the cutting station 7 . The conveying device 8 is then configured to convey the base ceramic slabs BCS through the decoration system 9 along the path P for the decoration of the base ceramic slabs BCS .

[0094] Finally, the plant 1 comprises a kiln 17 arranged along the path P downstream of the decoration station 12 to sinter the base ceramic slabs BCS so as to obtain the finished ceramic slabs CP . In particular, the kiln 17 is configured to impose a temperature ranging from at least about 1000 ° C to at least about 1300 ° C .

[0095] According to a preferred variant , the plant 1 then comprises a drier 14 arranged along the path P immediately upstream of the kiln 17 and downstream of the decoration station 12 , configured to heat the base ceramic slabs BCS up to a temperature of at least about 100 ° C ( in particular, of at least about 150 ° C ) and feed them to the kiln 17 . According to a possible variant , the plant 1 comprises a firing apparatus that integrates both the drier 14 and the kiln 17 therein, so as to substantially reduce the path of the base ceramic slabs BCS and the overall si ze of the plant 1 . Advantageously, the decoration system 9 may comprise further decoration stations and / or further electrostatic application stations . According to an advantageous but nonlimiting embodiment , the decoration system 9 comprises a further decoration station 28 arranged along the path P downstream of the kiln 17 . For example , the decoration station 28 is an electrostatic application station 28 . The electrostatic application station 28 is made to apply a final layer comprising a powder covering material . Advantageously, the covering material of the final layer can be any powder material , for example a fixing material , or a material such as to provide the surface S to be decorated with particular aesthetic properties ( for example particular shine ) and / or functional properties ( for example particular roughness ) .

[0096] The decoration station 12 comprises a printing assembly 15 to apply a layer on the surface S to be decorated of each base ceramic slab BCS . Preferably, the printing assembly 15 comprises a digital deposition assembly configured to digitally apply the layer so as to reproduce a design or pattern of predetermined decoration defined on the surface S to be decorated . In other words , the printing assembly 15 is made so that the applied layer defines a design or decoration on the surface S to be decorated .

[0097] The decoration station 12 further comprises an electrostatic application unit 22 . The electrostatic application unit 22 is configured to apply on the surface S to be decorated a layer consisting of a covering material , in particular powder . In other words , the drier 14 is interposed between the printing assembly 15 and the electrostatic application unit 22 . In this case , the decoration station 12 is arranged along the path P partially upstream of the drier 14 (with the printing assembly 15 ) and partially downstream of the drier 14 (with the electrostatic application unit 22 ) .

[0098] According to a possible embodiment , the decoration station 12 then comprises a printing assembly 21 configured to apply a layer of a precursor material (or primer ) on the surface S to be decorated . The printing assembly 21 is arranged along the path P immediately upstream of the printing assembly 15 . According to a first embodiment , the printing assembly 21 comprises a digital deposition member configured to digitally apply the layer of precursor material in an even manner over the entire surface S to be decorated .

[0099] Alternatively, the printing assembly 21 is arranged along the path P immediately downstream of the printing assembly 15 ( i . e . interposed between the printing assembly 15 and the electrostatic application unit 22 ) .

[0100] Alternatively, the printing assembly 21 comprises a digital deposition member configured to digitally apply the layer of precursor material only partially onto the surface S to be decorated . The digital deposition member is configured to apply the layer exclusively on a portion of the surface S to be decorated .

[0101] According to a possible variant shown in Figures 1 , 2 and 4 , the decoration station 12 comprises a decoration apparatus 70 configured to house ( enclose ) therein the printing assembly 15 and / or the electrostatic application unit 22 and / or the printing assembly 21 ( i f present ) so as to substantially reduce the path of the base ceramic slabs BCS and the overall si ze of the plant 1 . Advantageously but not necessarily, the printing assembly 15 comprises an ink-j et head configured to emit one or more j ets of material ( selectively) on the surface S to be decorated . In this case , advantageously but not necessarily, the applied material has a such a texture and viscosity that it can be applied by means of an ink-j et head . The printing assembly 15 is configured to apply a f irst layer exclusively on a portion of the surface S to be decorated .

[0102] According to a first embodiment , the printing assembly 15 is configured to apply a first layer comprising ( in particular, consisting of ) a material perfectly compatible with the powder covering material applied with the electrostatic application unit 22 . More in detail , the printing assembly 15 is configured to apply a layer comprising ( in particular, consisting o f ) a material chemically related to the powder covering material applied with the electrostatic application unit 22 . In this case , the decoration takes place by growth and the printing assembly 15 is configured to apply a layer that acts as an adhesion promoter for the powder covering material subsequently appl ied with the electrostatic application unit 22 .

[0103] In particular, the printing assembly 15 is configured to apply the layer ( in particular selectively) in the area of at least a first defined area of the surface S to be decorated .

[0104] Said first defined area is such that at least a second defined area of the same surface S to be decorated ( in particular, complementary to the first area ) remains free of material . In other words , in this case the extension of the first area is smaller than the extension of the entire surface S to be decorated.

[0105] The electrostatic application unit 22 is configured to deposit a second layer comprising (in particular, consisting of) powder covering surface in the full field (i.e., on the entire surface S to be decorated) . The powder covering material is mainly attracted in the first area.

[0106] Alternatively, the printing assembly 15 is configured to apply (in particular digitally) the material so as to reproduce a defined pattern on the surface S to be decorated. In other words, the printing assembly 15 is configured to apply the material so that the layer defines a pattern on the surface S to be decorated.

[0107] The electrostatic application unit 22 is configured to deposit a second layer comprising (in particular, consisting of) powder covering surface in the full field (i.e., on the entire surface S to be decorated) . The powder covering material is mainly attracted in the pattern.

[0108] According to a second embodiment, the printing assembly 15 is configured to apply a layer comprising (in particular, consisting of) a material totally incompatible with the powder covering material applied with the electrostatic application unit 22. In other words, the printing assembly 15 is configured to apply a layer comprising (in particular, consisting of) a material chemically different from the powder covering material applied with the electrostatic application unit 22. More in detail, the printing assembly 15 is configured to apply a layer comprising (in particular, consisting of) a material comprising functional groups with polar characteristics, such as for example water. In this case , the decoration takes place by inhibiting or repulsion of the powder covering material ; the printing assembly 15 is configured to apply a layer that acts as an adhesion inhibitor for the powder covering material subsequently applied with the electrostatic application unit 22 .

[0109] In particular, the printing assembly 15 is configured to apply the layer ( in particular selectively) on the surface S to be decorated, in the area o f at least a first defined area of the surface S to be decorated .

[0110] Said first defined area is such that at least a second defined area of the same surface S to be decorated ( in particular, complementary to the first area ) remains free of material . In other words , in this case the extension of the first area is smaller than the extension of the entire surface S to be decorated .

[0111] The electrostatic application unit 22 is configured to deposit a second layer comprising ( in particular, consisting of ) powder covering surface in the full field ( i . e . , on the entire surface S to be decorated) . The powder covering material is mainly attracted in the second area .

[0112] Alternatively, the printing assembly 15 is configured to apply ( in particular digitally) the material so as to reproduce the complementary of a pattern defined on the surface S to be decorated . In other words , the printing assembly 15 is configured to apply the material so that the layer defines the complementary of a pattern on the surface S to be decorated .

[0113] The electrostatic application unit 22 is configured to deposit a second layer comprising ( in particular, consisting of ) powder covering surface in the full field ( i . e . , on the entire surface S to be decorated) . The powder covering material is mainly attracted in the pattern .

[0114] The Applicant has veri fied that the material applied through the printing assembly 15 to ensure satis factory performance in the subsequent electrostatic application phase must have a working viscosity ranging from 3 cP to 100 cP, preferably ranging from 5 cP to 30 cP .

[0115] The Applicant has also veri fied that the precursor material to ensure satis factory performance in the subsequent decoration phases of the base ceramic slabs BCS must have a working viscosity ranging from 3 cP to 100 cP, preferably ranging from 5 cP to 30 cP .

[0116] According to what is shown in Figure 5 , the electrostatic application unit 22 comprises a fluidi zed tank 23 , which holds a powder fluidi zed with air . In particular, the tank 23 is provided with a bottom wall 24 having a number of through holes to allow air to enter .

[0117] To the fluidi zed tank 23 there is connected a pumping member 25 which draws from the fluidi zed tank 23 through a cannula 26 and feeds the powder fluidi zed with air to any number of dispens ing devices 27 through respective ducts 28 ( even a single dispensing device 27 ) .

[0118] The electrostatic application process of the powders takes place in an application booth 29 , preferably made of plastic material and enclosing the dispensing devices 27 therein . Advantageously, the electrostatic application unit 22 comprises a number of dispensing devices 27 ( i . e . at least two dispensing devices 27 ) . It is important to highlight that thanks to the presence of a number of dispensing devices 27 it is possible to obtain an even distribution of the powders on the surface S to be decorated . Advantageously, the dispensing devices 27 are arranged in line transversely to the moving direction A of the base ceramic slabs BCS .

[0119] From which the powders come out . Preferably, the number of dispensing devices 27 are equally spaced apart from one another to ensure greater uni formity in the electrostatic application of the powders on the surface S to be decorated . According to a first variant , the electrostatic application unit 22 comprises three dispensing devices 27 arranged in line .

[0120] According to a further variant , the dispensing devices 27 are at least four, arranged on at least two rows and at least two columns and preferably equally spaced apart from the adj acent dispensing devices 27 to ensure a uni form electrostatic application on the surface S to be decorated . The dispensing devices 27 are provided with respective axes transverse to the moving direction A of the base ceramic slabs BCS . In other words , the dispensing devices 27 are provided with respective axes transverse to the conveying plane defined by the conveying unit 2 . Preferably, the dispensing devices 27 are provided with respective axes orthogonal to the conveying plane defined by the conveyor assembly 2 . The axes of the dispensing devices 27 may be parallel to each other ; alternatively, the axes of the dispensing devices 27 may not be parallel to each other .

[0121] According to a first embodiment , the dispensing devices 27 comprise applying guns 27 . Each applying gun 27 is provided with a high-voltage electrode arranged in the area of a noz zle from which the powders exit . The applying guns 27 are made to electrostatically charge the particles of the powders directed towards the surface S to be decorated . The high-voltage electrode generates an electric field and emits electric charges that are trans ferred to the ceramic powders that fall by gravity and are attracted to the surface S to be decorated . The electrical charges emitted by the high- voltage electrode can alternatively be positive or negative .

[0122] Alternatively, the dispensing devices 27 comprise triboelectric devices for ceramic powders that exploit the triboelectric ef fect that allows , by means of rubbing ( in particular with a plastic material ) , the trans fer ( in particular, the removal ) of electric charges from the ceramic powders which fall by gravity and are attracted by the surface S to be decorated .

[0123] According to a further variant , the dispensing devices 27 comprise electrostatic rotary bell atomi zers for ceramic powders .

[0124] More generally, the dispensing devices 27 comprise any type of device configured to allow electrostatic deposition of the ceramic powders .

[0125] The electrostatic application unit 22 then comprises a recovery system, made to remove , preferably by means of suction, excess powders , in particular powders that do not stick to the surface S to be decorated . The recovery system comprises a suction mouth adapted to suck upwards the powders that has not stuck to the surface S to be decorated and to feed them to the fluidi zed tank 23 . Alternatively, the removal device could be configured to remove excess powders by means of blowing .

[0126] Furthermore , according to a preferred embodiment , the electrostatic application unit 22 comprises a removal system 31 , made to mechanically remove , preferably by means of scraping, excess powders , in particular powders that are not stuck to the surface S to be decorated that settle on the conveying device 8 . The excess powders settling on the conveying device 8 or falling below the conveying device 8 itsel f are recovered and returned to a sieving system which comprises a tank 32 , preferably housed below the conveying device 30 . The excess powders collected in the tank 32 are sieved and fed via a duct 33 , preferably by pneumatic transport , to a hopper 34 . From the hopper 34 the powders are fed back to the fluidi zed tank 23 .

[0127] According to a preferred embodiment , the powders used in the electrostatic application unit 22 have a particle si ze ranging from 5 pm to 100 pm (microns ) , preferably ranging from 15 pm to 50 pm (microns ) . Advantageously, the aforesaid powders comprise : frit of glass and / or clay and / or aluminium oxide ( or alumina ) and / or zirconium oxide and / or quartz sands and / or feldspars and / or calcium carbonate and / or further additives to increase the smoothness and modi fy the surface charge .

[0128] In the preceding discussion, explicit reference has been made to the case of a plant 1 that works continuously ( i . e . , which is configured to substantially continuously feed the layer LPM of ceramic powder material along the path P ) but the decoration station 12 described above can also find advantageous application in the case of a plant configured to operate substantially discontinuously ( or non- continuously ) . Both embodiments are characteri zed by the presence of a forming station that is arranged along the path P and is configured to obtain a number of slabs BCS of compacted ceramic powder, each provided with a respective surface S to be decorated by means of the decoration station

[0129] 12 located downstream along the path P . LIST OF REFERENCE NUMBERS OF THE FIGURES

[0130] 1 plant

[0131] 2 conveyor assembly

[0132] 3 conveyor belt

[0133] 4 input station

[0134] 5 workstation

[0135] 6 pressing unit

[0136] 7 cutting station

[0137] 8 conveyor belt

[0138] 9 decoration system

[0139] 12 decoration station

[0140] 14 drier

[0141] 15 printing assembly

[0142] 17 kiln

[0143] 18 feeding assembly

[0144] 21 printing assembly

[0145] 22 electrostatic application unit

[0146] 23 fluidi zed tank

[0147] 24 bottom panel

[0148] 25 pumping member

[0149] 26 cannule

[0150] 27 dispensing device

[0151] 28 ducts

[0152] 31 removal system

[0153] 32 tank

[0154] 33 duct 34 hopper

[0155] 35 roller

[0156] 36 upper compactor belt

[0157] 37 lower compactor roller

[0158] 38 upper compactor roller

[0159] 39 front motor roller

[0160] 40 rear duct roller

[0161] 52 decoration station

[0162] 53 printing assembly

[0163] 70 decoration apparatus

[0164] 90 belt conveyor

[0165] 91 roller conveyor

[0166] CP ceramic product

[0167] LPM layer of ceramic powder material

[0168] P path

[0169] A moving direction

[0170] SPM strip of compacted powdered material

[0171] BCS base ceramic slab

[0172] S surface to be decorated

Claims

CLAIMS1.- A plant (1) for the production of ceramic products (CP) comprising:- a forming station (5, 7) arranged along a path (P) and configured to obtain a number of slabs (BCS) of compacted ceramic powder, each provided with a respective surface (S) to be decorated; and- a kiln (17) arranged along the path (P) downstream of the forming station (5, 7) in a moving direction (A) and configured to set a temperature ranging from at least approximately 1000 °C to at least approximately 1300 °C for each base ceramic slab (BCS) in order to fire it; the plant is characterized in that it comprises a decoration station (12) arranged along said path (P) between the forming station (5, 7) and the kiln (17) and comprising:- a first application assembly (15) , in particular a first printing assembly (15) , configured to apply a first layer exclusively on a portion of the surface (S) to be decorated and comprising a preferably digital deposition member; and an electrostatic application unit (22) arranged downstream of the first application assembly (15) and configured to apply a second layer consisting of a powder covering material; wherein the electrostatic application unit (22) comprises a fluidized tank (23) , which holds the powder covering material fluidized with air, a number of dispensing devices (27) configured to be arranged facing the surface (S) to be decorated and provided with respective axes transverse to the moving direction (A) of the base ceramic slabs (BCS) and at least one pumping member (25)which draws from the fluidized tank (23) and feeds the powder covering material fluidized with air to the number of dispensing devices (27) .2.- The plant according to claim 1 and comprising a drier (14) which is arranged along the path (P) between the forming station (5, 7) and the decoration station (12) in the moving direction (A) and is configured to heat each base ceramic slab (BCS) to a temperature of at least about 100 °C.3.- The plant according to claim 1 and comprising a drier (14) which is arranged along the path (P) downstream of the decoration station (12) and upstream of the kiln (17) in the moving direction (A) and is configured to heat each base ceramic slab (BCS) to a temperature of at least about 100 °C.4.- The plant according to claim 1 and comprising a drier (14) which is arranged along the path (P) between the forming station (5, 7) and the kiln (17) in the moving direction (A) and is configured to heat each base ceramic slab (BCS) to a temperature of at least about 100 °C; wherein the first application assembly (15) is arranged upstream of the drier (14) in the moving direction (A) and the electrostatic application unit (22) is arranged downstream of the drier (14) in the moving direction (A) .5.- The plant according to any one of the preceding claims, wherein the decoration station (12) comprises a second application assembly (21) , in particular a second printing assembly (21) , to apply a layer of a precursor material on the surface (S) to be decorated with a preferably digital deposition member; wherein the second application assembly (21) is arranged upstream of the first applicationassembly ( 15) .6.- The plant according to any one of claims 1 to 4, wherein the decoration station (12) comprises a second application assembly (21) , in particular a second printing assembly (21) , to apply a layer of a precursor material on the surface (S) to be decorated with a preferably digital deposition member; wherein the second application assembly (21) is arranged downstream of the first application assembly (15) and upstream of the electrostatic application unit (22) .7.- The plant according to any one of the preceding claims, wherein the decoration station (12) comprises a decoration apparatus (70) configured to house therein the first printing assembly (15) and / or the electrostatic application unit (22) and / or a second printing assembly (21) .8.- The plant according to any one of the preceding claims, wherein the electrostatic application unit (22) is configured to apply the second layer of powder covering material in an even manner on said first layer.9.- The plant according to claim 8, wherein the first application assembly (15) is configured to apply the first layer exclusively on a first area or on a design / pattern of the surface (S) to be decorated; and wherein the second layer of powder covering material is mainly attracted on the first area or on the design / pattern of the surface (S) to be decorated .10.- The plant according to claim 8, wherein the first application assembly (15) is configured to apply the first layer exclusively on a first area or on a portion complementary to a design / pattern of the surface (S) to be decorated; and wherein the second layer of powder coveringmaterial is mainly attracted on a second area, different from and preferably complementary to the first area or on the design / pattern of the surface (S) to be decorated.11.- The plant according to any one of the preceding claims, comprising: a conveying device (2) configured to transfer a ceramic powder material along an initial segment of the path (P) in the moving direction (A) ;- a ceramic powder material input station (4) arranged along the initial segment of the path (P) and comprising a feeding assembly for feeding a mixture of ceramic powders; and wherein the forming station (5, 7) comprises a processing station (5) arranged along the path (P) downstream of the input station (4) and comprising a pressing unit (6) configured to compact the ceramic powder material so as to obtain a continuous strip (SPM) of compacted ceramic powder; and a cutting station (7) arranged along the path (P) and configured to cut the continuous strip (SPM) of compacted ceramic powder transversely to the moving direction (A) so as to obtain a plurality of slabs (BCS) of compacted ceramic powder, each provided with a respective surface (S) to be decorated .12.- The plant according to any one of the preceding claims, wherein the dispensing devices (27) are equally spaced apart from one another.13.- The plant according to any one of the preceding claims, wherein the electrostatic application unit (22) comprises a removal system (31) made to mechanically remove, preferably by means of scraping, excess powders that has not stuck the surfaces (S) to be decorated.14.- The plant according to any one of the preceding claims, wherein the electrostatic application unit (22) comprises a recovery system made to remove by means of suction or blowing, the excess powders that has not stuck to the surfaces (S) to be decorated.15.- The plant according to any one of the preceding claims, wherein at least one dispensing device (27) comprises an applying gun (27) having a nozzle in the area of which it is provided with a respective high-voltage electrode. 16.- The plant according to any one of the preceding claims, wherein at least one dispensing device (27) comprises a triboelectric device for ceramic powders.17.- The plant according to any one of the preceding claims, wherein at least one dispensing device (27) comprises an electrostatic rotary bell atomizer for ceramic powders.

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