Compaction method and system for compacting ceramic powder material

Abstract

A compaction method and system (100) for compacting powder material comprising: a transport surface (4) for advancing a layer (ST) of powder material comprising ceramic powder along a given path (P) in an advance direction (A); a belt compaction element (18); a pressing assembly (22) to compact the layer (ST) of powder material and obtain a layer (KP) of compacted powder material; a powder material deflection assembly ( 30 ), arranged upstream of the compaction station (6) and configured to intercept said layer (ST) of powder material at two side portions (12a, 12b) and to redistribute at least part of the powder material so as to obtain a layer (ST) of powder material having a substantially even thickness.

Description

[0001] COMPACTION METHOD AND SYSTEM FOR COMPACTING CERAMIC POWDER

[0002] MATERIAL

[0003] Cross-Reference To Related Applications

[0004] This patent appl ication claims priority from Italian patent application no . 102024000004453 filed on February 29 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0005] Field of the Art

[0006] The present invention relates to a compaction method and compaction system for compacting a powder material comprising ceramic powder . The present invention further relates to a plant for producing ceramic articles .

[0007] Background of the Invention

[0008] In the ceramics industry, systems are known for manufacturing ceramic articles , such as ceramic slabs or tiles , which involve the use of compaction devices .

[0009] Such systems for manufacturing ceramic articles typically comprise : a transport assembly which defines a transport surface adapted to transport ceramic powder through the various processing stations ; a ceramic powder feeding system adapted to progressively feed ( in particular, a defined quantity of ) ceramic powder material onto the transport assembly, in particular onto the transport surface , so as to form a layer of ceramic powder ; and a compaction device adapted to compact the layer of ceramic powder as it advances onto the transport surface through the compaction device so as to form a layer of compacted ceramic powder .

[0010] Downstream of the compaction station, there are generally further processing stations of known type , typically at least one cutting and / or trimming station, where the strip of compacted ceramic powder is broken up into individual slabs or tiles and / or is trimmed, typically at least at the longitudinal edges , and possibly further decorating and / or finishing stations before a firing station, at which the ceramic articles are fired so as to form the finished products .

[0011] It is known in the ceramic industry that the quality of the finished products obtained depends very much on the evenness , in terms of thickness , density, and distribution transverse to the advance direction ( i . e . , width-wise ) of the layer of ceramic powder which is fed to the compaction device .

[0012] In fact , for the compaction to occur properly, it is necessary to feed a layer of ceramic powder to the compaction device which is as even as possible in terms of density and thickness , and therefore has a substantially rectangular cross-section . The known compaction devices comprise, also for this reason, side containments sliding substantially in the same direction and at the same speed as the transport surface and adapted to laterally contain the layer of powder material during compaction, so that the density of the powder layer is as uni form as possible crosswise to the advance direction .

[0013] However, it is known that the powder material , once fed onto the transport assembly, naturally tends to accumulate inclined according to the falling angle which is a function of the friction angle of the ceramic powder, ef fectively forming on the transport assembly itsel f a layer of powder material having a trapezoidal cross-section with the end portions inclined by an angle substantially equal to the friction angle of the powder .

[0014] To date , in order to cope with thi s problem and thus to ensure a layer of powder material as even as possible in input to the compaction device , it is known to provide adj ustment systems of the layer of poser material placed upstream of the compaction station .

[0015] However, such known systems generally include physical separators , typically fixed barriers , perpendicular to the transport surface , arranged on the transport assembly, generally aligned with the side containments of the compaction device , along the advance direction, and configured to separate the central part of the layer of powder material (which is then fed to the compaction device ) , from the portions of inclined side ends . An example of a known solution including physical separators , in particular side walls , on the transport assembly is described in EP3260260A1 .

[0016] The known systems for handling / ad usting the layer of powder material typically require that the powder material forming such end portions is removed from the transport assembly, e . g . , by means of suction systems . Such solutions , however, result in the rej ection, and thus waste , o f at least part of such powder material with consequent economic losses .

[0017] Solutions exist which allow to recycle part of the removed powder material . However, such solutions cannot be used for any thickness of powder material , but only for thicknesses of the layer of powder material intended to manufacture ceramic articles up to 6- 8 mm . In order to solve at least part of such problems , the same applicant developed a solution described in international patent application W02015019166 , which, although ef fective, has a fairly complex structure and involves movements of ceramic powder along es sentially circular paths which inevitably induce a dispersion of powder into the surrounding environment and possibly also into the central part of the material layer, with all the inconveniences this entails . Moreover, this solution, although ef fective , in some cases ( for certain thicknesses of the layer of powder material ) induces undesirable thickening of ceramic powder at the side portions .

[0018] Another known solution is described in CN116352855A related to an apparatus for manufacturing ceramic artefacts which includes laterally trimming the layer of powder material before compacting it .

[0019] The aim of the present invention is to propose a compaction method and compaction system for compacting ceramic powder material which solves at least in part the problems of the devices of the prior art .

[0020] Summary

[0021] In accordance with the present invention, a compaction method and compaction system are proposed for compacting ceramic powder material , as claimed in the attached independent claims , and preferably, in any one of the claims directly or indirectly dependent on the mentioned independent claims .

[0022] The claims describe preferred embodiments of the present invention forming an integral part of the present disclosure . Brief Description of the Drawings

[0023] The invention wi ll now be described with reference to the accompanying drawings , which show some non-limiting examples of embodiments , wherein :

[0024] - Figure 1 is a schematic side view of a manufacturing plant of ceramic products in accordance with the present invention;

[0025] Figure 2 is a perspective view of part of the manufacturing plant of ceramic products of Figure 1 , wherein a layer of powder material advanced from a transport surface through a ceramic powder deflection assembly according to an embodiment of the present invention is illustrated;

[0026] - Figure 3 is an enlarged scale view of part of the view of Figure 2 to better illustrate the ceramic powder deflection assembly;

[0027] - Figure 4 is a schematic side view of the part of the manufacturing plant of ceramic products of Figure 2 from a first side ;

[0028] - Figure 4A is an enlarged scale view of the detail W of Figure 4 ; and

[0029] - Figure 5 is a schematic side view of the part of the manufacturing plant of ceramic products of Figure 2 from a second side .

[0030] Detailed Description

[0031] In the attached figures , the number 1 is used to indicate overall a manufacturing plant 1 of ceramic products T , for example ceramic slabs and / or tiles .

[0032] It should be noted that in the present discussion, terms such as "upper" , " lower" , " side" , " right" , " left" , " elevation" or "height" are used with reference to the manufacturing plant 1 of ceramic products T resting on a hori zontal plane , e . g . , resting on the ground or on a floor, whereby, for example , the terms " above" or "below" , " internally" or " externally" are used to refer, respectively, to "being above" or "being below" , " inwards" or "outwards" with respect to another component of the manufacturing plant 1 of ceramic products T when it is resting on the floor or on the ground . Furthermore , in the context of the present description, the term " second" component does not imply the presence of a " first" component . These terms are in fact used as labels to improve clarity and should not be understood in a limiting way .

[0033] The manufacturing plant 1 of ceramic products T comprises : a feeding system 2 ( known per se and not described in detail herein) configured to feed a measured quantity of powder material CP in a substantially continuous manner onto a transport assembly 3 to obtain a layer ST of powder material comprising ceramic powder ( in particular, the powder material is ceramic powder - e . g . , containing clay, sand and / or feldspar ) ; a compaction system 100 , which will be better described later in the present discussion, configured to receive on a transport surface 4 , which is part of the transport assembly 3 , the layer ST of powder material and compact it so as to obtain a layer KP of compacted powder material .

[0034] With particular reference to Figure 1 , advantageous ly, the transport assembly 3 is configured to convey the layer ST of material from an input station 5 to a compaction station 6 and the layer KP of compacted powder material from the compaction station 6 to an output station 7 along a given path P in an advance direction A, passing through further stations , in particular through at least one cutting station 8 .

[0035] More advantageously but not limitedly, the transport assembly 3 compri ses : a first conveyor belt 9 which extends from the input station 5 to ( in particular, up to the exit from) the compaction station 6 (which is adapted to support the layer ST of powder material from below) and which defines with its upper branch the aforementioned transport surface 4 ; and at least one other conveyor 10 , for example in the attached figure a roller conveyor, configured to convey the layer KP of compacted powder, or ( as in the embodiment illustrated in Figure 1 ) , of the base articles 15 formed starting from the layer KP of compacted powder material and convey them towards the output station 7 .

[0036] Advantageously, the layer ST of powder material fed onto the transport assembly 3 by the aforementioned feeding system 2 comprises a central portion 11 having a constant thickness ( in particular, an extension perpendicularly to the transport surface 4 ) , and two side portions 12a and 12b on the sides of the central portion 11 having, cros swise to the advance direction A, a thickness decreasing outwards ( in particular, moving away from the central portion 11 , i . e . , middle line of the transport surface 4 ) , the width of which, crosswise to the advance direction A, is a function of the friction angle of the powder material forming it .

[0037] Even more advantageously but not limitedly, the side portions 12a and 12b each have a triangular cross-section; i . e . , they have a decreasing side edge 13a, 13b, inclined by an angle which i s a function of the friction angle of the powder material forming the layer ST of powder material .

[0038] The manufacturing plant 1 of ceramic products T further comprises a cutting assembly 14 , arranged at the above- mentioned cutting station 8 , to cut the layer KP of compacted ceramic powder material parallel and crosswise to the direction A so as to obtain base articles 15 , each of which has a portion of the layer KP of compacted ceramic powder having a width, crosswise to the advance direction A, which is substantially equal to the width of the above-mentioned central portion 11 ; and a kiln 16 for sintering the compacted ceramic powder of the base articles 15 so as to obtain finished ceramic products T . Even more advantageously but not limitedly, the manufacturing plant 1 of ceramic products T further comprises a dryer 17 placed upstream of the kiln 16 along the given path P to dry the base articles 15 and possibly other processing stations (not illustrated and known per se ) to decorate and / or f inish the base articles 15 before firing them .

[0039] According to some advantageous but not limiting embodiments , the cutting assembly 14 ( only schematically illustrated in Figure 1 ) comprises : two trimming tools (not illustrated and known per se ) arranged downstream of the compaction station 6 along the advance direction A arranged at a distance from one another, crosswise to the advance direction A, approximately equal to the aforementioned width of the central portion 11 and each configured to cut the layer KP of compacted powder material , respectively, along a first cutting path parallel to the advance direction A and along a second cutting path, parallel to the first cutting path, for trimming the longitudinal edges of the layer KP of compacted powder material (more in particular, for removing from said layer KP of compacted powder material a portion having a width equal to the width of the side portions 12a and 12b of the layer ST of powder material ) and means for adj usting the mutual distance of the trimming tools .

[0040] Advantageously, the compaction system 100 comprises : a frame (not visible in the attached figures ) ; the aforementioned transport surface 4 , which advantageously but not limitedly forms part of the transport assembly 3 and is configured to receive and advance the layer ST of powder material comprising ceramic powder in an advance direction A from the aforementioned input station 5 to at least the aforementioned compaction station 6 ; an upper belt compaction element 18 , advantageously but not limitedly carried by the frame , and which, in turn, comprises a plurality of rollers 19a, 19b with hori zontal axis ( i . e . , each having a respective rotation axis perpendicular to the advance direction A) , of which ( in particular, comprising) at least one motori zed roller 19a and a return roller 19b, and an upper pres sing belt 20 wrapped around said plurality of rollers 19a, 19b to define with a lower branch thereof an upper compaction surface 21 , which is substantially facing the transport surface 4 along at least one section PA and is movable along the advance direction A; and a pressing assembly 22 arranged at a compaction zone 23 along the section PA of the given path P and configured to press the compaction surface 21 towards the transport surface 4 so as to compact the layer ST of powder material interposed between them and obtain the layer KP of compacted powder material .

[0041] According to some advantageous but not limiting embodiments of the present invention, for example the one schematically illustrated in Figure 1 , the pressing assembly 22 comprises a pair of pressing rollers 24 , 25 . More advantageously but not limitedly, the pressing assembly 22 comprises : a lower pressing roller 24 which has a hori zontal axis of rotation ( i . e . , perpendicular to the advance direction A and parallel to the transport surface 4 ) and is arranged below the transport surface 4 ; and an upper pressing roller 25 which is parallel to and overlaps the lower pressing roller 24 and which cooperates with the upper compaction surface 21 ( in particular, with the pressing belt 20 forming said compaction surface 21 ) to press the upper compaction surface 21 towards the transport surface 4 , at the aforementioned compaction zone 23 , so as to compact the layer ST of powder material and form the aforementioned layer KP of compacted ceramic powder material .

[0042] Advantageously, but not limitedly, in use , the lower pressing roller 24 and the upper pressing roller 25 are configured to keep the upper compaction surface 21 locally pressed towards the transport surface 4 so as to compress the layer ST of powder material interposed between them . In use , the layer ST of powder material is advanced, advantageously but not limitedly continuously, from the transport surface 4 through the predetermined compaction zone 23 , wherein the layer ST of powder material is compacted, thanks to the action of the pressing rollers 24 and 25 , as it advances along the advance direction A.

[0043] According to certain advantageous but not limiting embodiments , for example that schematically illustrated in Figure 1 , the compaction system 100 comprises a further lower belt compaction element 26 which, in turn, comprises a further plurality of rollers 27a, 27b with a horizontal axis , of which ( in particular, comprising) at least one motori zed roller 27a and one or more idler rollers 27b, and a further belt 28 wrapped around said plurality of rollers 27a, 27b and configured to define with the upper branch thereof a further lower compaction surface 29 , located below ( in particular, in direct contact with) the transport surface 4 . According to some embodiments not illustrated, this compaction area 29 coincides at least in part with the transport surface 4 .

[0044] Advantageously, the compaction system 100 further comprises a powder material deflection assembly 30 which is arranged upstream of the compaction station 6 along the given path P, is configured to intercept the layer ST of powder material at the side portions 12a, 12b of said layer ST of powder material and to redistribute ( at least part ; in particular, the entirety) of the powder material of said side portions 12a , 12b so as to obtain a layer ST o f powder material having a substantially even ( in particular, substantially constant ) thickness , perpendicularly to the advance direction A. In fact , it is known that the compaction of the layer ST of powder material is all the more ef ficient the more the layer ST of powder material which is fed to the pressing assembly 22 has a uni form thickness crosswise to the advance direction A.

[0045] Advantageously, the powder material deflection assembly 30 comprises : a pair of deflectors 31a, 31b which extend perpendicularly and above the transport surface 4 parallel to the advance direction A ( in particular, having a main axis of development substantially parallel to the advance direction A) along a section PB of the path determined upstream of the section PA, each arranged and configured to intercept , a side edge 13a, 13b of one of the side portions 12a, 12b of the layer ST of powder material and to deflect ( i . e . , push) , in particular inwards , at least part of the powder material of said side portions 12a, 12b ; and a pair of handling units 32a, 32b, each o f which cooperates with a respective deflector 31a and 31b to redistribute the deflected powder material and to obtain the aforementioned layer ST of powder material of uni form thickness ( see Figures 2 , 4 and 5 ) .

[0046] According to some advantageous but not limiting embodiments such as that illustrated in the attached figures , each pair of powder material handling units 32a, 32b comprises : a containing wall 33a, 33b extending parallel to the respective deflector 31a, 31b ( at a distance therefrom substantially equal to the width of each side portion 12a, 12b ) to laterally delimit a respective accumulation seat 34a, 34b which remains defined between the containing wall 33a, 33b and the corresponding deflector 31a, 31b ( and which, therefore , is comprised in the deflection assembly 30 , in particular in the relative handling unit ( 32a, 32b ) ) ; and a levelling barrier 35a, 35b ( see , for example , Figures 4A and 5 ) extending parallel to the transport surface 4 at the accumulation seat 34a, 34b to level the powder material located ( i . e . , advancing) at the accumulation seat 34a, 34b, more in particular to level such material as it advances on the transport surface 4 along the advance direction A.

[0047] Even more advantageously but not limitedly, such a levelling barrier 35a, 35b comprises ( in particular, consists of ) a screed ( see for example Figures 4A and 5 ) .

[0048] Alternatively or additionally, advantageously but not limitedly, the compaction system 100 ( in particular, each powder material handling unit 32a, 32b ) further comprises a moving device (not visible in the attached figures ) configured to move the levelling barrier 35a, 35b along a direction Z perpendicular to the transport surface 4 closer to or away from the transport surface 4 ; in particular, as a function of the thickness of the layer ST of powder material to be obtained, i . e . , the quantity of powder material accumulated in the accumulation seat 34a, 34b .

[0049] Advantageously but not limitedly, the compaction system 100 also comprises an electronic control unit CU ( schematically illustrated in Figure 1 ) , configured ( i . e . , programmed) to control the operation of at least the deflection assembly 30 and the transport surface 4 .

[0050] Advantageously, but not limitedly, the compaction system 100 further comprises a pair of side containing elements ( in particular, belts ) arranged at least at the compaction area 23 , and above the transport surface 4 to laterally contain the layer ST of powder material being fed to the pressing assembly 22 . Each side containing element is arranged along the above-mentioned section PA of the given path P, aligned along said advance direction A, to one of the deflectors 31a, 31b .

[0051] Advantageously, but not limitedly, each deflector 31a, 31b is configured to deflect at least part of the powder material of the side portion 12a, 12b towards the corresponding containing wall 33a, 33b so as to cause the build-up thereof in the accumulation seat 34a, 34b ( see Figures 2 to 5 ) .

[0052] Even more advantageously but not limitedly, each deflector 31a, 31b comprises ( in particular, is formed by) a wall ( in particular, an inner wall ) having, along the advance direction A, a development converging towards the middle line ( i . e . , towards the centre ; more in particular, towards the axis of longitudinal symmetry) of the transport surface 4 . More in particular, advantageously but not limitedly, each deflector 31a, 31b has a substantially triangular cross- section ( see for example Figures 2 and 3 ) . In other words , more advantageously but not limitedly, each deflector 31a, 31b comprises an outer vertical wall and at least one inner vertical wall ( in particular, arranged on the side opposite the outer vertical wall ) extending along an inclined direction with respect to the advance direction A by an angle greater than 0 ° ; in particular, by an angle between about 1 ° and about 50 ° ; even more preferably, by an angle between 15 ° and 30 ° .

[0053] According to some advantageous but not limiting embodiments , for example those illustrated in the attached figures , the deflectors 31a, 31b are arranged at a first distance from one another which, advantageously but not limitedly, is substantially equal to the total width of the layer ST of powder material . Alternatively or additionally, advantageously but not limitedly, the containing walls 33a, 33b of the powder material handling units 32a, 32b are arranged at a second distance from one another, which is smaller than the first distance and even more advantageously but not limitedly equal to the width of the aforementioned central portion 11 of the layer ST of powder material .

[0054] The accumulation seat 34a, 34b, in turn, has a width, crosswise to the advance direction A, which varies as a function of the thickness of the layer ST of powder material to be treated and the type of powder material ( in particular, the friction angle of such powder material ) . In more detail , advantageously but not limitedly, the accumulation seat 34a, 34b varies in width between about 5mm and about 50mm; more advantageously, between about 15 and about 40mm.

[0055] Even more advantageously but not limitedly, the compaction system 100 comprises an adj ustment device (not visible in the attached figures ) to adj ust the mutual position of the deflectors 31a, 31b so that the aforementioned first distance can be varied as the layer ST of powder material to be processed varies . Alternatively or additionally, said adj ustment device is intended to vary the distance of the handling units 32a, 32b ( in particular at least of the containing walls 33a, 33b ) as the layer ST of powder material to be treated varies so that the containing walls 33a, 33b are located at the separation plane ( represented in dashed line in Figures 2 and 3 ) between the central portion 11 and the side portions 12a, 12b so as to separate the part of the layer ST of powder material which will form the base articles 15 from that which will be trimmed by the aforementioned cutting assembly 14 .

[0056] Advantageously but not limitedly, the base articles 15 obtained with the above-described cutting assembly 14 are each formed by a portion of the compacted ceramic powder layer KP having a width, crosswise to the advance direction A, substantially equal to the di stance between the powder material handling units 32a, 32b . Even more advantageously but not limitedly, the trimming tools of the cutting assembly 14 are arranged at a distance from one another which is substantially similar to the distance between said powder material handling units 32a, 32b .

[0057] According to certain advantageous but not limiting embodiments , such as that illustrated, each of the containing walls 33a, 33b comprises ( in particular, is formed by) a flexible lamella made of plastic material which extends perpendicularly to the transport surface 4 and, advantageously but not limitedly, has an extension such that it intercepts the layer ST of powder material and leaves a mark thereon, along which, more advantageously but not limitedly, once the compaction has been carried out , the layer KP of compacted powder material will be trimmed, as will be better explained below .

[0058] According to some advantageous but not limiting embodiments , each powder material handling unit 32a, 32b comprises a suction device 36 extending into the accumulation seat 34a, 34b, upstream of the levelling barrier 35a, 35b along the advance direction A and is configured ( in particular, it is adj ustable in height along the aforementioned vertical direction Z ) to remove from the accumulation seat 34a, 34b a quantity of powder material so that the remaining part of powder material (which remains in said accumulation seat 34a, 34b ) can be redistributed to obtain, once levelled, the aforementioned layer ST of powder material having a substantially even thickness , perpendicularly to said advance direction A. In particular, advantageously but not limitedly, the suction device 36 comprises a suction mouth 37 extending into the accumulation seat 34a, 34b upstream from the levelling barrier along the section PA of the given path P and a suction unit (not visible in the attached figures ) , for example an aspirator, such as an impeller, to exert suction force through such a suction mouth 37 so as to be able to remove the powder material .

[0059] Alternatively or additionally, more advantageously but not limitedly, the suction device 36 is configured to exert an adj ustable suction force , for example by adj usting the distance of the suction mouth 37 from the transport surface 4 , so as to suck in a variable quantity of powder material based on the thickness of the layer ST of powder material , the type of powder material , the arrangement of the levelling barrier 35a, 35b etc . Therefore , the presence of such a suction device 36 allows to adj ust the quantity of powder material present in the accumulation seat 34a, 34b and, at the same time , to avert the risk that the deflected powder material , not being able to be contained in the accumulation seat 34a, 34b, exits therefrom, dirtying the rest of the compaction system 100 or compromising the quality of the remaining part of the layer ST of powder material .

[0060] Furthermore , the possibility of adj usting the suction force , e . g . , by adj usting the position of the suction mouth 37 , makes it possible to adj ust the quantity of powder to be accumulated in the accumulation seat 34a, 34b, and thus the density of the side portions 12a and 12b, to avoid the propagation of any imperfections and / or to adj ust the cutting assembly 14 to reduce or increase the width, crosswise to the advance direction A, of the edges to be trimmed . Alternatively or additionally, advantageously but not limitedly, the accumulation seat 34a, 34b is si zed to accommodate at most a defined quantity of powder material ; and each handling unit 32a, 32b comprises at least one second suction device 38 a, 38b ( see for example Figure 2 ) which is arranged upstream of the deflector 31a, 31b along the advance direction A and lateral to each deflector 31a, 31b, on the side opposite the corresponding powder material handling unit 32a, 32b, and is configured to suck a possible excess part exceeding said defined quantity of powder material deflected by the corresponding deflector 31a, 31b so as to avert the risk of said powder material exiting from the accumulation seat 34a, 34b, for example ending up on the transport surface 4 .

[0061] According to certain advantageous but not limiting embodiments , the deflection assembly 30 comprises at least one detector 39 , preferably but not limitedly a photocell , which is configured to detect the quantity of powder material in each accumulation seat 34a, 34b, and which is in connection with the aforementioned control unit CU, which is configured ( i . e . , programmed) to control the activation of at least the transport surface 4 also as a function of what is detected by the detector 39 . It is thereby possible to stop the feeding of the layer ST o f powder material whenever, for example due to mal functions or unforeseen events , the quantity of powder material deflected towards the accumulation seat 34a, 34b exceeds the defined quantity beyond a certain limit .

[0062] According to another aspect of the present invention, a method for compacting powder material comprising ceramic powder is presented, advantageously but not limitedly implemented with a compaction system 100 made according to one of the embodiments described above .

[0063] Advantageously, the method for compacting powder material of the present invention comprises the following steps : a compaction step, during which a layer ST o f powder material is compacted, advantageously by means of a compaction system 100 of the type described above , at a compaction station 6 so as to obtain a layer KP of compacted powder material ; and a conveying step, during which a layer ST of powder material conveys , advantageously by means of the conveyor assembly 3 of the type described above ( in particular, by means of a transport surface 4 which is part of the transport assembly 3 ) , along a given path P in an advance direction A from an input station 5 to the compaction station 6 and the layer KP of compacted powder material is conveyed from the compaction station 6 to the output station .

[0064] According to some advantageous but not limiting embodiments , the method further comprises a feeding step, during which the powder material is fed to the transport assembly 3 , which comprises the above-mentioned transport surface 4 at the input station 5 by means of a feeding device 2 . In particular, the conveying step and the feeding step are at least partially simultaneous .

[0065] Advantageously, the method for compacting powder material comprises a deflection step, ( at least partially) prior to the compaction step and simultaneous with the conveying step, during which a powder material deflection assembly 30 intercepts the layer ST of powder material at two side portions 12a, 12b of such a layer ST of powder material and redistributes the powder material of the side portions 12a and 12b so as to obtain a layer ST of powder material having a substantially homogeneous ( i . e . , constant ) thickness , perpendicularly to the advance direction A.

[0066] Advantageously, the material deflection assembly 30 comprises a pair of deflectors 31a, 31b extending perpendicularly and above the transport surface 4 parallel to the advance direction A of a section PB of the given path P and a pair of powder material handling units 32a, 32b each cooperating with a corresponding deflector 31a, 31b . Even more advantageously but not limitedly, the deflection assembly 30 is of the type described above in relation to the compaction system 100 . In more detail , each pair of powder material handling units 32a, 32b comprises a containing wall 33a, 33b extending parallel to the respective deflector 31a, 31b to laterally delimit a respective accumulation seat 34a, 34b which remains defined between the containing wall 33a, 33b and the corresponding deflector 31a, 31b, and a levelling barrier 35a, 35b extending parallel to the transport surface 4 at the respective accumulation seat 34a, 34b to level the powder material located ( in particular, advancing) at the accumulation seat 34a, 34b .

[0067] Advantageously but not limitedly, the deflection step comprises a first sub-step, during which each deflector 31a, 31b intercepts a side edge 13a, 13b of one of the side portions 12a, 12b, while the layer ST of powder material advances along the given path P, and deflects ( in particular, pushes ) at least part of the powder material of the relative side portion 12a, 12b towards the relative containing wall 33a, 33b and a second sub-step, during which said at least part of the powder material deflected towards the containing wall 33a, 33b is levelled by the levelling barrier 35a, 35b, as the layer ST o f powder material advances along the given path P to obtain a layer ST of powder material having a substantially homogeneous ( even) thickness .

[0068] Even more advantageously but not limitedly, the compaction method comprises a powder material removal step, ( at least partial ly) simultaneous with the deflection step, during which a suction device 36 , advantageously of the type described above , removes from the accumulation seat 34a, 34b a certain quantity of the powder material so that the remaining part of the powder material can be redistributed during the deflection step to obtain, once the powder material accumulated in the accumulation seat 34a, 34b has been levelled, a layer ST of powder material having a substantially homogeneous ( even) thickness .

[0069] Even more advantageously but not limitedly, such an allotment step al so comprises a safety sub-step, during which a further suction device 38a, 38b, arranged upstream of the deflector 31a, 31b along the advance direction A outside the accumulation seat 34a, 34b, sucks any excess powder material which has exited from the accumulation seat 34a, 34b .

[0070] According to some advantageous but not limiting embodiments , the compaction method further comprises a detection step, ( at least partially) simultaneous with the deflection step, during which at least one detector 39 , preferably but not limitedly a photocell , detects the quantity of powder material in each accumulation seat 34a, 34b ; and a control step, ( at least partially) simultaneous with the conveying step and the detection phase , during which a control unit CU controls the activation of the transport surface 4 as a function of what is detected in the detection step and stops the advancement of the layer ST of powder material along the advancement direction A whenever it detects a quantity of powder material exceeding the maximum quantity which can be contained in the accumulation seat 34a, 34b .

[0071] Advantageously but not limitedly, the suction device 36 also varies the quantity of powder material sucked as a function of what is detected by the detector 39 in the detection step .

[0072] The compaction method and compaction system 100 of the present invention have numerous advantages , including the following .

[0073] First and foremost , they allow the pressing assembly 22 to be fed with a layer ST of ceramic powder having a substantially even thickness crosswise to the advance direction A, reducing the risk of defects arising during compaction .

[0074] Furthermore , the method and the compaction system 100 of the present invention allow to control the density and thickness of the side portions 12a, 12b by suitably redistributing the ceramic powder forming them, thus obtaining a layer ST of powder material having a more even density across the width, crosswise to the advance direction A, and allowing, at the same time , to limit the propagation of possible defects from such side portions 12a, 12b to the central portion 11 which is the one which will then form the base ceramic articles 15 and therefore the finished products T .

Claims

CLAIMS1. A compaction system (100) for compacting powder material comprising ceramic powder; the compaction system(100) comprises: a transport surface (4) configured to receive and advance a layer (ST) of powder material comprising ceramic powder along a given path (P) in an advance direction (A) ; a belt compaction element (18) , which, in turn, comprises a compaction surface (21) , which substantially faces said transport surface (4) and is movable along said advance direction (A) ; a pressing assembly (22) arranged at a compaction zone (23) along said given path (P) and configured to press the compaction surface (21) towards the transport surface (4) so as to compact said layer (ST) of powder material comprising ceramic powder interposed between them and obtain a layer (KP) of compacted powder material; a powder material deflection assembly (30) which is arranged upstream of said compaction station (6) along said given path (P) , is configured to intercept said layer (ST) of powder material comprising ceramic powder at two side portions (12a, 12b) , and to redistribute at least part of the powder material of said two side portions (12a, 12b) so as to obtain a layer (ST) of powder material comprising ceramic powder having a substantially even (in particular, constant) thickness, perpendicularly to said advance direction (A) , and comprises a pair of deflectors (31a, 31b) which extend perpendicularly and above said transport surface (4) parallel to said advance direction (A) , each configured to intercept a side edge (13a, 13b) of one ofsaid side portions (12a, 12b) and to deflect at least part of the powder material of said side portion (12a, 12b) and a pair of powder material handling units (32a, 32b) , each of which cooperates with a respective deflector (31a, 31b) of said pair of deflectors (31a, 31b) to redistribute the powder material deflected by the corresponding deflector (31a, 31b) ; each pair of powder material handling units (32a, 32b) comprising a containing wall (33a, 33b) which extends parallel to the respective deflector (31a, 31b) so as to laterally delimit a respective accumulation seat (34a, 34b) which remains defined between the containing wall (33a, 33b) and the corresponding deflector (31a, 31b) , and a levelling barrier (35a, 35b) which extends parallel to said transport surface at said accumulation seat (34a, 34b) to level the powder material located (in particular, advancing) at said accumulation seat (34a, 34b) ; and each deflector (31a, 31b) being configured to deflect the said at least part of the powder material of the side portion (12a, 12b) towards the corresponding containing wall (33a, 33b) so as to cause the build-up thereof in the accumulation seat (34a, 34b) .

2. The compaction system (100) for compacting powder material according to claim 1, wherein each deflector (31a, 31b) comprises (in particular, consists of) a wall having, along the advance direction (A) , a development converging towards the middle line of the transport surface (4) .

3. The compaction system (100) for compacting powder material according to claim 1 or 2, wherein said deflectors(31a, 31b) are arranged at a first distance from one anotherand said containing walls (33a, 33b) of the powder material handling units (32a, 32b) are arranged at a second distance from one another, which is smaller than the first distance; in particular, said first distance being substantially similar to the width, crosswise to the advance direction (A) , of said layer (ST) of powder material comprising ceramic powder .

4. The compaction system (100) for compacting powder material according to claim 3, comprising an adjustment device to adjust the position of the deflectors (31a, 31b) of said pair of deflectors (31a, 31b) and / or of said powder material handling units (32a, 32b) ; in particular, at least of said containing walls (33a, 33b) .

5. The compaction system (100) for compacting powder material according to any one of the preceding claims, wherein each pair of powder material handling units (32a, 32b) comprises a moving device configured to move said levelling barrier (35a, 35b) along a direction (Z) , which is perpendicular to the transport surface (4) , closer to or away from the transport surface (4) ; in particular, as a function of the thickness of the layer (ST) of powder material comprising ceramic powder.

6. The compaction system (100) for compacting powder material according to any one of the preceding claims, wherein each powder material handling unit (32a, 32b) comprises a first suction device (36) extending into said accumulation seat (34a, 34b) upstream of said levelling barrier (35a, 35b) along said advance direction (A) and is configured to remove, from said accumulation seat (34a, 34b) , a quantity of said powder material so that the remainingpart of powder material can be redistributed to obtain said layer (ST) of powder material comprising ceramic powder having a substantially even thickness, perpendicularly to said advance direction (A) .

7. The compaction system (100) for compacting powder material according to any one of the preceding claims wherein: said accumulation housing (34a, 34b) is sized to accommodate at most a defined quantity of powder material; and each powder material handling unit (32a, 32b) comprises at least one second suction device (38a, 38b) which is arranged upstream of the deflector (31a, 31b) along said advance direction (A) and is configured to suck a possible excess part exceeding said defined quantity of powder material .

8. The compaction system (100) for compacting powder material according to any one of the preceding claims, comprising a control unit (CU) configured to control the activation of at least said transport surface (4) ; the deflection assembly (30) comprising at least one detector (39) configured to detect the quantity of powder material in each accumulation seat (34a, 34b) ; said control unit (CU) being connected to said detector (39) and being configured to control the activation at least of said transport surface (4) as a function of the data detected by said detector (39) .

9. A manufacturing plant (1) of ceramic products (T) comprising : a transport assembly (3) configured to convey a layer (ST) of powder material comprising ceramic powder from an input station (5) to a compaction station (6) and a layer(KP) of compacted powder material from a compaction station (6) to an output station (7) along a given path (P) in an advance direction (A) ; a feeding system (2) configured to feed a measured quantity of powder material onto the transport assembly (3) so as to obtain said layer (ST) of powder material comprising ceramic powder; at least one compaction system (100) for compacting powder material according to any one of the preceding claims configured to compact said layer (ST) of powder material and to obtain a layer (KP) of compacted powder material; a cutting assembly (14) to cut said layer (KP) of compacted powder material parallel to said advance direction (A) and crosswise to said advance direction (A) so as to obtain base articles (15) , each having a portion of said layer (KP) of compacted ceramic powder having a width, crosswise to the advance direction (A) , substantially equal to the distance between the handling units; and at least one kiln (16) to sinter the compacted ceramic powder of the base articles (15) so as to obtain finished ceramic products (T) .

10. The manufacturing plant (1) of ceramic products (T) according to claim 9, wherein: said cutting assembly (14) comprises two trimming tools arranged downstream of said compaction station (6) along said advance direction (A) at a third distance from one another, crosswise to the advance direction (A) , each configured to cut said layer (KP) of compacted powder material along a first cutting path parallel to said advance direction (A) and along a second cutting path parallel tothe first cutting path, respectively, so as to trim the longitudinal edges of the layer (KP) of compacted ceramic material, and means to adjust the mutual distance of said trimming tools; said third distance is substantially similar to the distance between said pairs of handling units (32a, 32b) .

11. A compaction method for compacting powder material comprising ceramic powder; the method comprises at least the following steps: a compaction step, during which a layer (ST) of powder material comprising ceramic powder is compacted, at a compaction station (6) , so as to obtain a layer (KP) of compacted powder material; a conveying step, during which the layer (ST) of powder material comprising ceramic powder is conveyed along a given path (P) in an advance direction (A) from an input station (5) to the compaction station (6) and the layer (KP) of compacted ceramic material is conveyed from the compaction station (6) to the output station (7) ; a deflection step, which is at least partially prior to said compaction step and simultaneous with said conveying step, during which a powder material deflection assembly (30) , comprising a pair of deflectors (31a, 31b) which extend perpendicularly and above said transport surface (4) parallel to said advance direction (A) and a pair of powder material handling units (32a, 32b) each cooperating with a corresponding deflector (31a, 31b) , intercepts said layer (ST) of powder material comprising ceramic powder at two side portions (12a, 12b) and redistributes the powder material of said two side portions (12a, 12b) so as to obtaina layer (ST) of powder material comprising ceramic powder having a substantially even (in particular, constant) thickness, perpendicularly to said advance direction (A) ; each pair of powder material handling units (32a, 32b) comprising a containing wall (33a, 33b) which extends parallel to the respective deflector (31a, 31b) so as to laterally delimit a respective accumulation seat (34a, 34b) which remains defined between the containing wall (33a, 33b) and the corresponding deflector (31a, 31b) , and a levelling barrier (35a, 35b) which extends parallel to said transport surface (4) at said accumulation seat (34a, 34b) to level the powder material located (in particular, advancing) at said accumulation seat (34a, 34b) ; and said deflection step comprising a first sub-step, during which each deflector (31a, 31b) of said pair of deflectors (31a, 31b) intercepts a side edge (13a, 13b) of one of said side portions (12a, 12b) while said layer (ST) of powder material comprising ceramic powder advances along said given path (P) , and deflects (in particular, pushes) at least part of the powder material of said side portion (12a, 12b) towards the relative containing wall (33a, 33b) and a second sub-step, during which said at least part of the powder material of said side portion (12a, 12b) deflected towards the containing wall (33a, 33b) is levelled by the levelling barrier (35a, 35b) as the layer (ST) of powder material comprising ceramic powder advances along the given path (P) to obtain a layer (ST) of powder material comprising ceramic powder having a substantially even thickness.

12. The compaction method for compacting powder material according to claim 11, comprising a powder materialremoval step, which is at least partially simultaneous with said deflection step, during which at least one first suction device ( 36 ) removes , from said accumulation seat ( 34a, 34b ) , a quantity of said powder material so that the remaining part of the powder material can be redistributed during said deflection step so as to obtain a layer ( ST ) of powder material comprising ceramic powder having a substantially even thickness , perpendicularly to said advance direction (A) .

13. The compaction method for compacting powder material according to claim 11 or 12 , comprising a detection step, which is at least partially simultaneous with said deflection step, during which at least one detector ( 39 ) detects the quantity of powder material in each accumulation seat ( 34a, 34b ) ; and a control step, which is at least partially simultaneous with said conveying step and said detection step and during which a control unit ( CU) controls the activation of the transport surface ( 4 ) as a function of what is detected in said detection step and stops the advancement of said layer ( ST ) of powder material comprising ceramic powder along said advance direction (A) each time it detects a quantity of powder material exceeding the maximum quantity which can be contained in the accumulation seat .14 . The compaction method for compacting powder material according to any one of claims 11 to 13 , implemented with a compaction system ( 100 ) according to any one of claims 1 to 8 .

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