OSSANI LUIGI (IT)
| WO2005068146A2 | 2005-07-28 |
| CN101549522A | 2009-10-07 | |||
| EP2065150A1 | 2009-06-03 |
| CLAIMS 1.- A machine for compacting a powder material (CP) comprising ceramic powder; the machine (2) comprises a compacting device (3) , which is arranged at a work station (4) and is adapted to compact the powder material (CP) so as to obtain a layer of compacted powder material (KP) ; a conveyor assembly (5) to transport the powder material (CP) along a first section (PA) of a given path in a feed direction (A) from an inlet station (6) to the work station (4) and the layer of compacted powder material (KP) from the work station (4) along a second section (PB) of the given path; and a feeding assembly (9), which is adapted to feed the powder material (CP) to the conveyor assembly (5) at the inlet station (6) and comprises a transfer chamber (TC) adapted to contain and to transfer the powder material (CP), in particular along a transfer path (TP); the machine (1) being characterized in that the transfer chamber (TC) has at least one first wall (10), which is crosswise to the feed direction (A) and comprises a deformable section (45) so as to vary the area of a cross section of at least one part of the transfer chamber (TC) . 2.- The machine according to claim 1, and comprising a movement unit (46) for modifying the deformable section (45) so as to vary the area of said cross section; in particular, the transfer chamber (TC) comprises at least one second wall (11) crosswise to the feed direction (A), in particular facing said first wall (10) . 3.- The machine according to claim 1 or 2, wherein the feeding assembly (9) comprises a first feeding device (24), which is adapted to contain (and, in particular, to feed to the transfer chamber (TC) ) a powder material (CA) of a first type; a second feeding device (25), which is adapted to contain (and, in particular, to feed to the transfer chamber (TC) ) a powder material (CB) of a second type; and an operation device (32), which is adapted to control the passage of the powder material to the transfer chamber (TC) from the first feeding device (24) and from the second feeding device (25) . 4.- The machine according to claim 3, wherein the first feeding device (24) comprises a respective first containment chamber (26) having a relative first outlet (27), the longitudinal extension of which is crosswise (in particular, perpendicular) to the feed direction (A) ; the second feeding device (25) comprises a respective second containment chamber (28) having a relative second outlet (29), the longitudinal extension of which is crosswise (in particular, perpendicular) to the feed direction (A) ; the first outlet (27) has respective first passage zones (30) arranged in succession along the longitudinal extension of the first outlet (27) ; the second outlet (29) has respective second passage zones (31) arranged in succession along the longitudinal extension of the second outlet (29); the operation device (32) is adapted to allow the powder material (CA; CB) to selectively exit through one or more of the first and second passage zones (30, 31) . 5.- The machine according to claim 3 or 4, and comprising a detection device (40) to detect how far in length the conveyor assembly (5) transports the powder material (CP) along the given path, and a control unit (34), which is adapted to store a reference distribution (35) of the powder material (CA, CB) of the first and second type which it is desirable to obtain in the powder material (CP) transported by the conveyor assembly (5) and to control the operation device (32) according to the findings of the detection device (19) and the reference distribution (21) . 6.- The machine according to any one of the preceding claims, wherein the deformable section (45) comprises a first section (47) adapted to rotate around a first substantially fixed oscillation axis (48) and at least one second section (49) adapted to rotate around a second substantially fixed oscillation axis (50) to vary the area of said cross section. 7.- The machine according to claim 6, wherein the first and second section (47, 49) are in contact with each other. 8.- The machine according to claim 6 or 7, wherein said first section (47) and said second section (49) are adapted to slide over each other while they oscillate around the first and second oscillation axis (48, 50) respectively. 9.- The machine according to any one of the claims 6 to 8, and comprising a movement unit (46) to cause the second section (49) to rotate around the second rotation axis (50) and a pushing device to push the first section (47) towards the second section (49) . 10.- The machine according to any one of the claims 6 to 9, wherein the first wall (10) comprises at least a third section (51), having at least one portion substantially fixed with respect to said first oscillation axis (48); the second section (49) is at least partially interposed between the first section (47) and the third section (51) . 11.- A The machine according to any one of the preceding claims, wherein the feeding assembly (9) (in particular, the transfer chamber (TC) ) comprises at least one forwarding assembly (12), which comprises a first mobile surface (13') arranged in the area of the first wall (10) ; and a first movement device to move the first mobile surface (13') transversally to the feed direction (A) towards the conveyor assembly (5), in particular along at least one given section of the transfer path (TP) ; in particular, the given section corresponds to said second section (49) . 12.- The machine according to claim 11, wherein the forwarding assembly (12) comprises a belt (13) arranged at the first wall (10) and having said mobile surface (13') . 13.- The machine according to any one of the preceding claims, wherein the transfer chamber (TC) comprises at least a second wall (11), crosswise to the feed direction (A), facing the first wall (10) and arranged upstream of the first wall (10) with respect to the feed direction (A) ; in particular, the forwarding assembly (12) further comprises at least one second belt (17) arranged at least partially at the second wall (11) and a second movement device (18) to move the second belt (17) towards the conveyor assembly (5) . 14.- A plant for the production of ceramic articles; the plant comprises at least one machine (1) for compacting ceramic powder according to any one of the preceding claims and provided with a cutting assembly (14) to transversally cut the layer of compacted ceramic powder (KP) so as to obtain base articles (15), each of which has a portion of the layer of compacted ceramic powder (KP) ; and at least one kiln (22) to sinter the compacted ceramic powder (KP) of the base articles (15) so as to obtain the ceramic articles (T) . 15.- A method of compacting a powder material (CP) comprising ceramic powder; the method comprises at least one compacting step, during which the powder material (CP) is compacted, at a work station (4), so as to obtain a layer of compacted powder material (KP) ; a conveying step, during which the powder material (CP) is conveyed by means of a conveyor assembly (5) along a first section (PA) of a given path from an inlet station (6) to the work station (4) and the layer of compacted powder material (KP) is conveyed from the work station (4) along a second section (PB) of the given path; and a feeding step, during which the powder material (CP) is fed to the conveyor assembly (4) at the inlet station (6) by means of a feeding assembly (7); in particular, the conveying step and the feeding step are at least partially simultaneous; the feeding assembly (7) comprises a transfer chamber (TC) which, during the feeding step, contains and transfers the powder material (CP) ; the method being characterized in that the transfer chamber (TC) has at least one first wall (10), which is crosswise to the feed direction (A) and has a deformable section (45) ; the method comprises a variation step, during which the area of a cross section of at least one part of the transfer chamber is modified by changing the shape of the deformable section (45) . 16.- The method according to claim 15, wherein the first wall (10), in particular the deformable section (45), comprises a first section (47) and at least one second section (49); during the variation step, the area of said cross section is modified by rotating the first section (47) around a first substantially fixed oscillation axis (48) and the second section (49) around a second substantially fixed oscillation axis (50) . 17.- The method according to claim 15 or 16, wherein the feeding assembly (9) (in particular, the transfer chamber (TC) ) has at least one forwarding assembly (12) which comprises a first mobile surface (13') arranged in the area of the first wall (10) ; during the feeding step, the first mobile surface (13') moves transversally to the feed direction (A) towards the conveyor assembly (5) . 18.- The method according to any one of the claims from 15 to 17, wherein the transfer chamber (TC) has at least one second wall (11), crosswise to the feed direction (A), facing the first wall (10) and arranged upstream of the first wall (10) with respect to the feed direction (A) ; in particular, the forwarding assembly (12) comprises at least one second mobile surface (17') arranged at the second wall (11); during the feeding step, the second mobile surface (17') moves transversally to the feed direction (A) towards the conveyor assembly (5) . 19.- The method according to one of the claims from 15 to 18, wherein the feeding assembly (9) comprises a first feeding device (24) which feeds, during the feeding step, a powder material (CA) of a first type to the transfer chamber (TC) , and a second feeding device (25) which feeds, during the feeding step, a powder material (CB) of a second type to the transfer chamber (TC) . 20.- The method according to claim 19 wherein, during the conveying step, a detection device (40) detects how far in length the conveyor assembly (5) transports the powder material (CP) along the given path in the feed direction (A) ; during the feeding step, a control unit (34) controls the feeding assembly (9) so as to vary the distribution of the powder material (CA, CB) of the first type and of the second type in a direction crosswise to the feed direction (A) according to the findings of the detection device (40) and a reference distribution (35) of the powder material (CA, CB) of the first and second type which it is desirable to obtain in the powder material (CP) transported by the conveyor assembly (5); in particular, the powder material (CA) of the first type has a different colour from the colour of the powder material (CB) of the second type. 21.- The method according to claim 20, wherein the first feeding device (24) comprises a respective first containment chamber (26) containing the powder material (CA) of the first type and having a relative first outlet (27), the longitudinal extension of which is crosswise (in particular, perpendicular) to the feed direction (A) ; the second feeding device (25) comprises a respective second containment chamber (28) containing the powder material (CB) of the second type and having a relative second outlet (29), the longitudinal extension of which is crosswise (in particular, perpendicular) to the feed direction (A) ; the first outlet (27) has respective first passage zones (30) arranged in succession along the longitudinal extension of the first outlet (27) ; the second outlet (29) has respective second passage zones (31) arranged in succession along the longitudinal extension of the second outlet (29); the feeding assembly (9) further comprises an operation device (32) which is adapted to allow exit of the powder material (CA, CB) selectively through one or more of the first and second passage zones (30, 31); during the feeding step, the control unit (34) operates the operation device (32) so that the powder material (CA, CB) passes selectively through one or more of the first or second passage zones (30, 31) . 22.- The method according to one of the claims from 15 to 21, implemented by a machine (2) according to one of the claims from 1 to 13. |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority from International PCT Application No. PCT/ IB2018 / 051563 filed on 09/03/2018, the disclosure of which is incorporated by reference.
TECHNICAL FIELD
The present invention relates to a method and a machine for compacting a powder material comprising ceramic powder. The present invention furthermore relates to a plant for the production of ceramic articles.
BACKGROUND TO THE INVENTION
In the field of the production of ceramic articles (in particular, slabs; more in particular, tiles) the use of machines for compacting semi-dry powders (ceramic powders; typically with humidity content of approximately 5-6%) is known. Such machines comprise ceramic powder feeding devices of different types.
Often these machines are used to manufacture products that imitate natural stone, such as marble and/or granite. These products have internal veins distributed at random within the products .
Alternatively or additionally, it may be expedient to use powders of different types to obtain articles with particular structural and/or physical characteristics.
In some cases, mixtures of powders of different colours are placed, randomly distributed, inside steel mould cavities and then compressed so as to obtain, for example, slabs of compacted powder.
The production of slabs with randomly distributed powders of different colours has been proposed also using continuous compacting machines which comprise a conveyor assembly for transporting (in a substantially continuous manner) the powder material along a given path from an inlet station through a work station, at which a compacting device is arranged, which is adapted, by the cooperation of pressure rollers, to compact the powder material so as to obtain a layer of compacted powder. A feeding assembly transfers the powder material to the conveyor assembly at of the inlet station.
An example of a continuous machine for compacting ceramic powder is described in the international patent application with publication number W02005/068146 by the same applicant as the present application.
The creation (for example by means of digital printing) of a graphic decoration over the layer of compacted ceramic powder so as to make the finished article visually more similar to a natural product is also known.
The systems available up to now for compacting ceramic powders have several drawbacks. These include the following.
Conveying of the powder material by the feeding assembly is not always easy (e.g. at times agglomerates and/or blockages can form) . This negatively affects both the structural quality of the final product and the productivity (e.g. at times production has to be interrupted to free the blockages) .
The distribution of the powders is modified in a non- controlled manner during transport to the conveyor assembly by the feeding assembly.
The veins within the articles (and therefore visible from the edge of the articles) are very rarely in a coordinated position with respect to the surface decorations obtained by printing .
The aesthetics of the product are significantly affected by the above, making its non-similarity with respect to a natural product (for example marble) much more evident.
The object of the present invention is to provide a machine and a method for compacting powder material and a plant and a procedure for the production of ceramic articles which overcome, at least partially, the drawbacks of the known art and at the same time are easy and inexpensive to produce.
SUMMARY
According to the present invention, a machine and a method are provided for compacting powder material and a plant for the production of ceramic articles, as claimed in the following independent claims and, preferably, in any one of the claims depending directly or indirectly on the independent claims.
BRIEF DESCRIPTION OF THE FIGURES
The invention is described below with reference to the attached drawings, which illustrate some non-limiting implementation examples, in which:
- figure 1 is a schematic side view of a plant according to the present invention;
- figure 2 is a schematic side view of a detail of a machine of the plant of figure 1 on an enlarged scale;
- figure 3 is a schematic side view of an alternative embodiment of the detail of figure 2;
- figure 4 illustrates the detail of figure 3 in a different operating configuration;
- figure 5 is a front view (with parts removed for clarity) of a detail of the machine of the plant of figure 1;
- figure 6 illustrates on an enlarged scale a section along the line VI-VI of figure 5;
- figure 7 is a rear view of the part of figure 5; - figure 8 is a perspective schematic view of a part of the plant of figure 1;
- figure 9 is a virtual representation of a part of the control procedure of the plant of figure 1;
- figure 10 is a side view, partially in section and on an enlarged scale, of a detail of the plant of figure 9; and
- figure 11 is a frontal schematic view of a detail of figure
2.
DETAILED DISCLOSURE
In figure 1, the number 1 indicates overall a plant for the production of ceramic articles T. The plant 1 is provided with a compacting machine 2 to compact the powder material CP, comprising ceramic powder (in particular, the powder material CP is ceramic powder - e.g. containing clay, sand and/or feldspar) .
In particular, the ceramic articles T produced are slabs (more precisely, tiles) .
The machine 2 comprises a compacting device 3, which is arranged at a work station 4 and is adapted to compact the powder material CP so as to obtain a layer of compacted powder KP; and a conveyor assembly 5 to transport (in a substantially continuous manner) the powder material CP along a section PA of a given path (in a feed direction A) from an inlet station 6 to the work station 4 and the layer of compacted powder KP (in particular, in the direction A) from the work station 4 along a section PB of the given path (in particular, to an outlet station 7) . In particular, the given path consists of the sections PA and PB.
The machine 2 is also provided with a feeding assembly 9, which is adapted to feed the ceramic powder CP to the conveyor assembly 5 at the inlet station 6. In particular, the feeding assembly 9 is adapted to feed the ceramic powder to the conveyor assembly 5 in a substantially continuous manner.
In particular, the conveyor assembly 5 is also adapted to support from below the powder material CP and the compacted powder material KP .
With particular reference to figures 2, 3 and 4, the feeding assembly 9 comprises a transfer chamber TC adapted to contain and transfer the powder material CP (in particular, along a transfer path TP; in particular, mainly in a transfer direction B crosswise to the feed direction A) .
According to some non-limiting embodiments, the transfer chamber TC is adapted to transfer the powder material CP mainly in the direction B substantially perpendicular to the feed direction A.
More precisely, the transfer chamber TC is adapted to transfer the powder material CP to the (onto the) conveyor assembly 5. Even more precisely, the transfer chamber TC has an (open) end arranged at the inlet station 6 (and the conveyor assembly 5) .
The transfer chamber TC has at least one wall 10, which is crosswise (more precisely, perpendicular) to the feed direction A.
According to some non-limiting embodiments (like the one illustrated in figure 2), the wall 10 is substantially parallel (or has at least one section substantially parallel) to the transfer direction B.
Alternatively (see, for example, figures 3 and 4), the wall 10 is (slightly) inclined with respect to the direction B. In particular, the transfer chamber TC has at least one further wall 11 crosswise (more precisely, perpendicular) to the feed direction A. More in particular, the wall 11 faces the wall 10. Even more in particular, the walls 10 and 11 are arranged in succession in the direction A (the wall 10 is arranged downstream of the wall 11) .
According to some non-limiting embodiments, at least either the wall 10 or the wall 11 (in particular, the wall 11) is substantially perpendicular to the feed direction A.
In some non-limiting cases, the walls 10 and 11 are (figure 2) substantially parallel to each other (or have respective sections substantially parallel to each other - figures 3 and 4) .
According to some non-limiting embodiments, the transfer chamber TC also has side walls, laterally delimiting the transfer chamber TC, crosswise (perpendicular) to the (and connecting the) walls 10 and 11. In particular, the side walls are substantially parallel to the direction A.
Advantageously but not necessarily, the feeding assembly 9 (in particular, the transfer chamber TC) comprises at least one forwarding assembly 12, which comprises at least one mobile surface 13' arranged at the wall 10 and a movement device 14 (schematically illustrated in figures 2 to 4) to move (in particular, by sliding) the mobile surface 13' (transversally to the direction A) towards the conveyor assembly 5 (in particular, along at least one first given section of the transfer path TP; more in particular, in the direction B) .
More precisely, the forwarding assembly 12 comprises at least one belt 13 arranged at least partially at the wall 10 and the movement device 14 (schematically illustrated in figure 2) to move the belt 13 (in particular, by sliding it) (transversally to the direction A) towards the conveyor assembly 5 (in particular, along at least one first section of the transfer path TP; more in particular, in the direction B) . In particular, the surface 13' is the inner surface (facing the inside of the transfer chamber TC) of the belt 13.
More precisely, the movement device 14 is adapted to move the belt 13 in a movement direction C (crosswise to the feed direction A) .
It should be noted that in the embodiment of figure 2, the direction B and the direction C substantially coincide. In the configuration of the embodiment of figure 4 the direction B and the direction C are crosswise to each other.
In particular, the belt 13 is moved (caused to slide) along a closed path (defined by the extension of the belt 13), one section of which coincides with a section of the transfer path TP .
Due to the forwarding assembly 12 it is surprisingly possible to facilitate the passage of the powder material CP along the transfer chamber TC. Furthermore, it has been noted that when powder materials of different type are used, said powder materials are more difficult to mix together (their distribution is not substantially altered) since they have a greater tendency to maintain their relative position.
More precisely, the movement device 14 comprises at least one motorized pulley 15 (i.e. connected directly or by means of a mechanism to a drive 16 of the movement device 14) ; in particular, the belt 13 is (at least) partially wound around the pulley 15. More precisely, but not necessarily, the drive 16 (for example an electric motor) is adapted to rotate the pulley 15 around an axis thereof (crosswise, in particular perpendicular, to the direction A and, more in particular, B) . According to some non-limiting embodiments, the forwarding assembly 12 (more precisely, the movement device 14) comprises a plurality of (two, in the embodiment of figure 2) pulleys (of which the pulley 15 is part) around which the belt 13 is wound .
In particular, the belt 13 defines at least one section of the wall 10.
According to some non-limiting embodiments, the belt 13 comprises (in particular, is composed of) a polymer material (for example polyurethane) .
Advantageously but not necessarily, the forwarding assembly 12 comprises at least one mobile surface 17' arranged at the wall 11 and a movement device 18 to move the mobile surface 17' (transversally to the direction A) towards the conveyor assembly 5 (in particular, along at least one respective second given section of the transfer path TP; more in particular, in the direction B) . In particular, the first given section and the second given section of the transfer path TP are (at least) partially coinciding.
More precisely, the forwarding assembly 12 comprises at least one further belt 17 arranged at least partially at the wall 11 and a movement device 18 to move the belt 17 transversally to the direction A (in particular, towards the conveyor assembly 5) . In particular, the belt 17 defines at least one section of the wall 11. In particular, the surface 17' is the inner surface (facing the inside of the transfer chamber TC) of the belt 17.
Advantageously but not necessarily, the movement device 18 is adapted to move (and, in use, moves) the mobile surface 17' (more precisely, the belt 17) at a speed substantially equal to the speed at which the movement device 14 is adapted to move (and, in use, moves) the mobile surface 13' (more precisely, the belt 13) .
According to some non-limiting embodiments, the movement device 18 comprises at least one motorized pulley 19 (i.e. connected, directly or by means of a mechanism, to a drive - e.g. the drive 16) ; in particular, the belt 13 is (at least) partially wound around the pulley 19. More precisely, the drive is adapted to rotate the pulley 19 around an axis thereof (crosswise, in particular perpendicular, to the directions A and B) . In particular, the rotation axis of the pulley 19 is substantially parallel to the rotation axis of the pulley 15.
According to some non-limiting embodiments, the forwarding assembly 12 (more precisely, the movement device 18) comprises a plurality of pulleys (of which the pulley 19 is part) around which the belt 17 is wound. In some non-limiting cases, one of said pulleys is a tensioner pulley.
With particular reference to figures 3 and 4, according to some non-limiting embodiments, the forwarding assembly 12 comprises a further belt 17* (arranged between the belt 17 and the conveyor assembly 5) . In particular, also the belt 17* is moved by a respective motorized pulley 19' .
In particular, the belt 17* defines a section of the wall 11 crosswise to the direction A (and, in particular, to the direction C) . More in particular, in this way, the transfer of the powder material CP to the (onto the) conveyor assembly 5 is facilitated.
According to some non-limiting embodiments, the forwarding assembly 12 comprises a deflecting element 12* (in particular, having a pointed shape; more in particular having substantially triangular section) around which the belt 17* is partially wound (and on which, in use, the belt 17* slides) .
More precisely, the deflecting element 12* is arranged at the inlet station 6 (at one end of the section PA) .
Advantageously but not necessarily (with particular reference to figures 3 and 4) , at least one of the pulleys (for example the pulley 20) of the movement device 14 is a tensioner pulley. As will become clearer below, this aspect is particularly important when one or more pulleys are moved.
Advantageously but not necessarily, the movement device 14 comprises (figures 2 and 11) an adjustment assembly 21 to adjust the transverse position (with respect to the longitudinal extension of the belt 13) of the belt 13.
In particular, the adjustment assembly 21 is adapted to detect the transverse position of the belt 13 and to move the belt 13 transversally (with respect to the longitudinal extension of the belt 13) . The adjustment assembly 21 is particularly useful because the belt 13 is typically relatively wide (even two metres) and short.
More in particular, the adjustment assembly 21 comprises one or more sensors (e.g. proximity sensors - known per se and not illustrated) adapted to detect the position of one of the (longitudinal) edges of the belt 13; even more in particular, said sensor/s is/are arranged at the cited edge.
According to some non-limiting embodiments, the adjustment assembly 21 comprises an adjustment roller 22, which is in contact with the belt 13 and has a respective rotation axis 23 and a positioning device (known per se and not illustrated) to rotate the roller 22 so that the rotation axis 23 modifies its orientation (in particular, with respect to the longitudinal extension of the belt 13; additionally or alternatively, with respect to the direction C; additionally or alternatively, with respect to the direction A; additionally or alternatively, with respect to the rotation axis of the pulley 15) . By modifying the orientation of the rotation axis 23, it is possible to transversally move the belt 13 (which slides partially on the roller 22) .
The positioning device is adapted to rotate the adjustment roller 22 so that the rotation axis 23 modifies its orientation with respect (to the direction C and) to the rotation axis of the pulley 15.
According to some non-limiting embodiments, not illustrated, the movement device 18 comprises an adjustment assembly to adjust the transverse position (with respect to the longitudinal extension of the belt 17) of the belt 17. Said adjustment assembly is defined as indicated above for the adjustment assembly 21.
Advantageously but not necessarily, the feeding assembly 9 comprises (see in particular figures 8 and 10) a feeding device 24 and a feeding device 25 arranged above the conveyor assembly 5 (and transfer chamber TC) .
The feeding device 24 is adapted to contain (and feed) a (ceramic) powder material CA of a first type.
More precisely, the feeding device 24 comprises a respective containment chamber 26 (see in particular figure 4) having a relative outlet 27, the longitudinal extension of which is crosswise (in particular, perpendicular) to the feed direction
A.
The feeding device 25 is adapted to contain (and feed) a (ceramic) powder material CB of a second type.
More precisely, the feeding device 25 comprises a respective containment chamber 28 having a relative outlet 29, the longitudinal extension of which is crosswise (in particular, perpendicular) to the feed direction A.
In particular, the longitudinal extensions of the outlets 27 and 29 are substantially parallel to each other.
In particular, the containment chamber 26 is adapted to contain the powder material CA and the containment chamber 28 is adapted to contain the powder material CB (different from the powder material CA) .
In particular, the powder material CP consists of one or both the powder materials CA and CB . More precisely, the powder material CP comprises (is composed of) the powder materials CA and CB .
According to some non-limiting embodiments, the powder materials CA and CB (are ceramic and) have different colours. In this way it is possible to create chromatic effects within the ceramic articles T. Said chromatic effects can be seen for example in the edges of the ceramic articles. Alternatively or additionally, the powder materials CA and CB are adapted to give the ceramic articles T different physical characteristics .
It should be noted that the presence of the transfer chamber TC is particularly advantageous when the feeding assembly 9 comprises feeding devices 24 and 25. In these cases, in fact, it has been experimentally noted that the deformation of the distribution of the powders CA and CB during their passage through the transfer chamber TC is reduced. With particular reference to figure 8, deformation of the strip of powder material CA within the powder material CP (arranged on the conveyor assembly 5) is reduced.
According to some non-limiting embodiments, the outlet 27 has respective passage zones 30 (see, in particular, figures 8 and 10) arranged in succession along the longitudinal extension of said outlet 27. The outlet 29 has respective passage zones 31 arranged in succession along the longitudinal extension of said outlet 29.
Advantageously but not necessarily, the feeding assembly 9 comprises an operation device 32, which is adapted to (selectively) adjust passage of the powder material from the feeding device 24 and from the feeding device 25 (to the transfer chamber TC) .
In particular, the operation device 32 is adapted to allow outlet of the powder material selectively through one or more of the passage zones 30 and 31. In particular, each passage zone 30 is arranged beside (more precisely, opposite; in particular, is associated with) a respective passage zone 31.
According to some non-limiting embodiments, the machine 1 further comprises (figures 1 and 8) a detection device 33 (for example an encoder) to detect how far in length the conveyor assembly 5 transports the powder material CP along the given path (in the feed direction A), in particular along the section PA, and a control unit 34, which is adapted to store (has stored) a reference distribution 35 (figure 9) of the powder material CA and CB of the first and second type (which it is desirable to obtain) in the powder material CP transported by the conveyor assembly 5 and to control the operation device 32 according to the findings of the detection device 33 and the reference distribution 35. More in particular, the control unit 34 is adapted to control the operation device 32 according to the findings of the detection device 33 so as to reproduce (on the conveyor assembly 5) the reference distribution 35.
According to some non-limiting embodiments (see, in particular, figures 8 and 10), the operation device 32 comprises a plurality of drive units 36 (only some of which are illustrated in figure 8), each of which is arranged at a respective passage zone 30 or (and/or) 31 and is adapted to control the passage of the powder material through the respective passage zone 30 or (and/or) 31.
In this way, it is possible to obtain (at any time) an (accurate) mixture of the powder materials CA and CB .
In particular, the operation units 36 are arranged in succession (in a crosswise direction - in particular, perpendicular - to the feed direction A) along the longitudinal extension of the outlet 27 or (and/or) 29.
Advantageously but not necessarily, each operation unit 36 comprises at least one respective shutter 37 and a respective actuator 38 (for example an electric actuator) adapted to move (substantially horizontally) the shutter 37 between a locking position (shown in figure 10) , in which the shutter 37 prevents the passage of powder material through the respective passage zone 30 and/or 31, and an opening position (not illustrated) , in which the shutter 37 at least partially does not prevent the passage of powder material through the respective passage zone 30 and/or 31.
According to some non-limiting embodiments (like the one illustrated in figures 8 and 10), the operation device 32 comprises two groups (rows) of drive units 36, each of said groups (rows) being associated with one of the containment chambers 26 and 28. Each drive unit 36 is adapted to control the passage of the powder material through a respective passage zone 30 or 31 (not both) .
Advantageously but not necessarily, the control unit 34 comprises a memory, in which the reference distribution 35 is stored (figure 9) . The control unit 34 is adapted to feed the reference distribution 35 along a virtual path VP through a virtual reference front RP as a function of (according to) the findings of the detection device 33. More in particular, the control unit 34 is adapted to feed the reference distribution 35 along the virtual path VP through a virtual reference front RP of the length detected by the detection device 33.
The virtual reference front RP has a plurality of positions, each of which corresponds to a passage zone 30 and a passage zone 31 adjacent to each other. The control unit 34 is adapted to allow outlet of the powder material CA and/or CB at a specific moment through the passage zones 30 and/or 31 according to the type of powder material CA and/or CB scheduled at the specific moment, in the reference distribution 35, in the positions of the virtual reference front RP corresponding to said passage zones 30 and/or 31.
In other words, the control unit 34 is adapted to allow the outlet of the powder material CA and/or CB at a specific moment through each passage zone 30 and/or 31 according to the type of powder material scheduled for each position given by the intersection between the virtual reference front RP with the reference distribution 35 at that specific moment.
More precisely, for example, if at a specific moment the virtual reference front RP intersects in a given position an area of the reference distribution 35 in which the powder material CA of the first type is scheduled, the passage zone 30, which corresponds to the given position, will be (kept) open, while the passage zone 31, which corresponds to the given position, will be (kept) closed. Advantageously but not necessarily, the transfer chamber TC is arranged between the feeding devices 24 and 25 on one side and the conveyor assembly 5 on the other. In particular, the transfer chamber TC is arranged below the feeding devices 24 and 25 and above the conveyor assembly 5.
In this way it is possible to compensate for any temporary discontinuities in feeding of the powder material.
Advantageously but not necessarily, the compacting machine 2 comprises a detection device 40, which is adapted to detect the level of powder material inside the transfer chamber TC. The control unit 34 is adapted to drive the operation device 32 according to the level of powder material CP detected inside the transfer chamber TC. In particular, the control unit 34 is adapted to drive the operation device 32 so as to maintain the level of the powder material CP inside the transfer chamber TC below a maximum level (and above a minimum level) . More precisely, the control unit 34 is adapted to drive the operation device 32 so as to activate feeding of the powder material to the transfer chamber TC when, in use, the quantity of powder material is below a first reference level, and block the feeding of powder material in the transfer chamber TC when, in use, the quantity of powder material is above a second reference level. In some cases, the first and the second reference level coincide.
According to some non-limiting embodiments (like the one illustrated in figure 8), the detection device 40 is provided with a plurality of sensors 41, each of which is adapted to detect the level of powder material CP inside the transfer chamber TC (substantially vertically) below a respective passage zone 30 (and/or 31) . The control unit 34 is adapted to activate each operation unit 36 according to the findings of the sensor 41 arranged below the respective passage zone 30 (and/or 31) . In particular, the control unit 34 is adapted to allow the passage of powder material through a passage zone 30 (and/or through the adjacent passage zone 31) when the corresponding sensor 41 (i.e. the sensor 41 positioned vertically below the zone 30 and/or 31) does not detect the presence of powder material in the transfer chamber TC (at its own position) , and to block the passage of powder material through a passage zone 30 (and/or through the adjacent passage zone 31) when the corresponding sensor 41 (namely the sensor 41 positioned vertically below the zone 30 and/or 31) detects the presence of powder material in the transfer chamber TC (in its own position) .
Each sensor 41 comprises (consists of), for example, an optical, or resistive, or capacitive detector, etc. According to some specific non-limiting embodiments, the detection device 40 comprises (is composed of) a row of sensors 41 (only some of which are illustrated in figure 8) with pitch (for example) of 10 mm. In these cases, the operation device 32 comprises an operation device 36 with pitch (for example) of 10 mm.
According to some non-limiting embodiments, the plant 1 comprises a printing device 42 (figure 1), which is adapted to create a graphic decoration over the layer of compacted ceramic powder KP transported by the conveyor assembly 5 and is arranged at a printing station 43 (arranged upstream of the outlet station 7) along the given path (in particular, along the section PB) downstream of the work station 4. The control unit 34 is adapted to control the printing device 42 so as to create a graphic decoration coordinated with the cited reference distribution 35, in particular so that a graphic decoration of a particular colour is (selectively) transferred to the powder material CA.
Advantageously but not necessarily, the plant 1 comprises a further application assembly 44 to cover at least partially the powder material CP with a layer of a further powder material. In particular, the application assembly 44 is arranged along the given path (more precisely along the section PA) upstream of the work station 4 (and upstream of the printing station 43) .
Advantageously but not necessarily, the wall 10 comprises a deformable section 45 so as to vary the area of a cross section (with respect to the direction B) of at least a part of the transfer chamber TC.
It has been experimentally observed that by varying the area of the cross section it is possible to reduce the risk of possible blockages in the transfer chamber TC and, in particular, surprisingly vary the form of the distribution of the powder materials CA and/or CB within the layer of powder material CP transported by the conveyor assembly. In this way, a more natural effect can be obtained also within the ceramic articles T.
By way of example, figures 3 and 4 illustrate an embodiment of the machine 2 in two operating configurations. In the first (figure 3) the area of the section is reduced; in the second (figure 4) the area of the section is increased.
In particular, the machine 2 (more precisely, the transfer chamber TC) comprises a movement unit 46 (for example a mechanism connected to an electric motor or comprising a fluid-dynamic actuator) to modify the deformable section 45 so as to vary the area of the cited cross section.
Advantageously but not necessarily, the wall 10 (more precisely, the deformable section 45) comprises a first section 47 (in particular, a strap), adapted to rotate around an oscillation axis 48 (crosswise to the direction A - and, in particular, to the direction C - and) substantially fixed and at least a second section 49 (in particular, a section of the belt 13) adapted to rotate around an oscillation axis 50 (crosswise to the direction A - and, in particular, to the direction C - and) substantially fixed to vary the area of the cited cross section. In particular, the axes 48 and 50 are substantially parallel to each other (more in particular, they are crosswise to the direction B) .
According to some non-limiting embodiments, the sections 47 and 49 are in contact with each other and are adapted to slide over each other while they rotate (oscillate) around the axes 48 and 50, respectively.
According to some non-limiting embodiments, the movement unit 46 is adapted to rotate the section 49 around the axis 50.
Advantageously but not necessarily, the machine further comprises a pushing device (of per se known type and not illustrated - for example, a spring device) to push the section 47 towards (against) the section 49 (in particular, so as to rotate - oscillate - the section 47 around the axis 48) .
The wall 10 comprises at least one further section 51, having at least one substantially fixed portion (more precisely, the section 51 is substantially fixed) with respect to the axis 48 (and the axis 50) . In particular, the section 49 is (at least partially) interposed between the sections 47 and 51.
In some non-limiting cases (like the one illustrated in figures 3 and 4) , the axis 50 is arranged at the section 51 (more precisely, at one end of the section 51) .
According to some non-limiting embodiments, the section 49 corresponds (at least) partially to the above-mentioned first given section (along which the mobile surface 13' extends) . According to some non-limiting embodiments not illustrated, also the wall 11 has a deformable section (analogous to the deformable section 45) .
Advantageously but not necessarily, the feeding assembly 9 is adapted to modify (over time) the quantity of powder material CP which it feeds to the conveyor assembly 5.
In particular, the machine 1 comprises a detection device 52 (arranged downstream of the work station) , which is adapted to detect the density of the layer of compacted powder KP . The control unit 34 is adapted to control the feeding assembly 9 so as to vary (over time) the quantity of powder material CP transported by the conveyor assembly 5 to the work station 4 according to the findings (the density of the layer of compacted ceramic powder KP detected) of the detection device 52.
In these cases, operation of the machine is as described in the patent application with publication number W02017 /216725 by the same applicant.
In particular, the feeding assembly 9 comprises a delivery unit 53 similar to the delivery unit described in W02017 /216725 (identified therein by number 21) .
The delivery unit 53 (in practice a lower end of the feeding assembly 9 and of the transfer chamber TC) is adapted to bring a layer of powder material CP (non-compacted) on a conveyor belt 54 of the conveyor assembly 5 to the area of the inlet station 6 and comprises a cross member 55 (in pen - figures 3 to 7), which is crosswise to the feed direction A, (partially) around which the belt 13 slides (becoming deformed) and which is arranged above the conveyor belt 54 so as to delimit an opening 56 between the belt 13 and the conveyor belt 54, the height of which (distance between the cross member 55 and the conveyor belt 54) defines the thickness of the layer of powder material CP on the conveyor belt 54. In particular, in use, the layer of powder material CP passes through the opening 56.
In these cases, the feeding assembly 9 (more precisely, the delivery unit 53) comprises at least one actuator 57 to vary the height of the opening 56 (or the distance between the cross member 55 and the conveyor belt 54) .
The actuator 57 can for example comprise (be) a hydraulic actuator controlled electronically and/or a brushless electric motor (more specifically, stepper) .
According to more specific but non-limiting embodiments (like those illustrated in figures 5 to 7), the feeding assembly 9 (more precisely, the delivery unit 53) comprises a plurality of actuators 57 arranged in succession transversally to the feed direction A (in particular, arranged along a line crosswise - more precisely substantially perpendicular - to the direction A) and which can be operated (are adapted to be operated) independently from each other so as to (deform the cross member 55 - described below in greater detail - and therefore) vary the height of zones of the opening 56 in a differentiated manner.
In other words, the actuators 57 can be operated so that the distance between the cross member 55 (in particular, the belt 13) and the conveyor belt 54 is varied in a differentiated manner transversally to the feed direction A.
More precisely, the control unit 34 is adapted to operate the actuators 57 independently of one another so as to (deform the cross member 55 and therefore) vary the height of zones of the opening 56 in a differentiated manner. In particular, the cross member 55 comprises (is made of) an elastically deformable material (typically, an elastomer) .
According to some embodiments a connecting arm 58 is provided extending between each actuator 57 and the cross member 55. In particular, the arm 58 is bound to the cross member 55 by means of an insert 59 embedded in the cross member 55 itself.
Advantageously but not necessarily, the conveyor assembly 5 is adapted to transport (and, in use, transports) the powder material CP along the section PA at a speed substantially equal to the speed at which the movement device 14 is adapted to move (and, in use, moves) the mobile surface 13' (more precisely, the belt 13) . More precisely, the conveyor belt 54 moves at a speed substantially equal to that at which the belt 13 moves .
In particular (see figure 1), the machine 1 also comprises a cutting assembly 60 to transversally cut the layer of compacted ceramic powder KP so as to obtain slabs (base articles) 61, each of which has a portion of the layer of compacted ceramic powder KP . More in particular, the cutting assembly 60 is arranged along the section PB of the given path (between the work station 4 and the printing station 29) . The slabs 61 comprise (consist of) compacted ceramic powder KP .
Advantageously but not necessarily, the cutting assembly 60 comprises at least one cutting blade 62, which is adapted to come into contact with the layer of compacted ceramic powder KP to cut it transversally (to the direction A) .
According to some non-limiting embodiments, the cutting assembly 60 also comprises at least two further blades 63, which are arranged on opposite sides of the section PB and are adapted to cut the layer of compacted ceramic powder KP and define lateral edges of the slabs 61 (and substantially parallel to the direction A) - if necessary by dividing the slab into two or more longitudinal portions. In some specific cases, the cutting assembly 60 is like the one described in the patent application with publication number EP1415780.
In particular, the plant 1 comprises at least a kiln 64 to sinter the layer of compacted ceramic powder KP of the slabs 61 so as to obtain the ceramic articles T. More in particular, the kiln 64 is arranged along the given path (more precisely along the section PB) downstream of the printing station 43 (and upstream of the outlet station 7) .
According to some non-limiting embodiments, the plant 1 further comprises a dryer 65 arranged along the section PB downstream of the work station 4 and upstream of the printing station 43.
In some cases, the feeding assembly 9 is adapted to bring a layer of (non-compacted) powder material CP to the (onto the) conveyor assembly 5 (in particular, onto the conveyor belt 54; more in particular at the inlet station 6) ; the compacting device 3 is adapted to exert a pressure onto the layer of ceramic powder CP crosswise (in particular, normal) to the surface of the conveyor belt 54.
According to some non-limiting embodiments, downstream of the conveyor belt 54 the conveyor assembly 5 comprises a sequence of transport rollers.
According to some non-limiting embodiments, in particular, the compacting device 3 comprises at least two compression rollers 67 arranged on opposite sides (one above and one below) of the conveyor belt 54 to exert a pressure on the powder material CP so as to compact the powder material CP (and obtain the layer of compacted powder KP) . Although only two rollers 67 are illustrated in figure 1, in accordance with some variations it is also possible to provide a plurality of rollers 67 arranged above and below the conveyor belt 54, as described for example in the patent EP1641607B1, from which further details of the compacting device 3 can be obtained.
Advantageously (as in the embodiment illustrated in figure 1) but not necessarily, the compacting device 3 comprises a pressure belt 68, which converges towards the conveyor belt 54 in the feed direction A. In this way, a pressure is exerted (from top to bottom) which gradually increases in the direction A on the powder material CP so as to compact it.
According to specific non-limiting embodiments (like the one illustrated in figure 1), the compacting device also comprises a counter belt 68' arranged on the opposite side of the conveyor belt 54 with respect to the pressure belt 68 to cooperate with the conveyor belt 54 to provide adequate resistance to the downward force exerted by the pressure belt 68. In particular, the pressure belt 68 and the counter belt 68' are (mainly) made of metal (steel) so that they cannot be substantially deformed while pressure is exerted on the ceramic powder.
According to some non-limiting embodiments not illustrated, the counter belt 68' and the conveyor belt 54 coincide. In these cases, the conveyor belt 54 is (mainly) made of metal (steel) and the counter belt 68' is absent.
Advantageously but not necessarily the detection device 52 is arranged (along the section PB) upstream of the kiln 64 (in particular, downstream of the dryer 65) .
Advantageously but not necessarily the printing device 42 is arranged (along the section PB) upstream of the kiln 64 (in particular, downstream of the dryer 65; more in particular, downstream of the detection device 52) .
According to some non-limiting embodiments, the transfer chamber TC (which extends vertically below the feeding devices 24 and 25) has a width of approximately 29-69 mm and a height of approximately 129-179 mm. Typically, the detection device 40 (and therefore the sensors 42) are arranged at approximately 79-109 mm from the lower end of the transfer chamber TC. In accordance with possible embodiments, the outlet arranged at the lower end of the transfer chamber TC has a height (according to requirements) of approximately 5-79 mm; in this way, the layer of powder material CP transported by the conveyor assembly 5 has an analogous thickness of approximately 5-79 mm.
In use, the powder material is provided by the feeding device 24 and/or 25 on the basis of the outcome of the intersection between the virtual reference front RP and the reference distribution 35 operating specific drive units 36 to cause the powder material to flow out of specific passage zones 30 and/or 31 when the specific respective sensors 41 indicate a level of powder material in the transfer chamber TC (at the specific sensors 41) below a reference threshold level.
In accordance with one aspect of the present invention, a method for compacting a powder material CP comprising ceramic powder is also provided. The method comprises at least one compacting step, during which the powder material CP is compacted, in the area of a work station 4, so as to obtain a layer of compacted powder material KP; a conveying step, during which the powder material CP is conveyed (in a substantially continuous manner) by means of a conveyor assembly 5 along a first section PA of a given path from an inlet station 6 to the work station 4 and the layer of compacted powder material KP is conveyed (in a substantially continuous manner) from the work station 4 along a second section PB of the given path; and a feeding step, during which the powder material CP is fed to the conveyor assembly 5 in the area of the inlet station 6 by means of a feeding assembly 9. In particular, the conveying step and the feeding step are at least partially simultaneous.
The feeding assembly 9 comprises a transfer chamber TC which, during the feeding step, contains and transfers the powder material CP (in particular, along a transfer path TP; in particular, in a transfer direction B) .
The transfer chamber TC has at least one wall 10, which is crosswise to the feed direction A.
Advantageously but not necessarily, the transfer chamber TC also comprises at least one forwarding assembly 12 which has a mobile surface 13' arranged at the wall 10. During the feeding step, the mobile surface 13' moves (slides) transversally to the feed direction A towards (the inlet station 6 and) the conveying assembly 5.
According to some non-limiting embodiments, the feeding assembly 9 comprises a feeding device 24, which feeds (in particular, during the feeding step) a powder material CA of a first type to the transfer chamber TC; a feeding device 25, which feeds (in particular, during the feeding step) a powder material CB of a second type to the transfer chamber TC; and an operation device 32, which adjusts (in particular, during the feeding step) the passage of powder material to the transfer chamber TC (selectively) from the feeding device 24 and from the second feeding device 25.
Advantageously but not necessarily, the transfer chamber TC comprises at least one further wall 11 crosswise to the feed direction A and facing the wall 10. The forwarding assembly 12 comprises a further mobile surface 17' arranged in the area of the second wall 10. During the feeding step, the mobile surface 17' moves transversally to the direction A towards (the inlet station 6 and) the feeding assembly 9.
According to some non-limiting embodiments, during the feeding step, the mobile surface 13' moves in a direction C of movement crosswise to the direction A of feed towards (the inlet station 6 and) the conveying assembly 5. In particular, the method comprises an adjustment step, during which the position of the mobile surface 13' is adjusted in a direction crosswise to the feed direction A and to the movement direction C. More in particular, the adjustment step comprises a detection sub-step, during which the position of the mobile surface 13' (transversally to the direction C) is detected, and a movement sub-step, during which the mobile surface 13' is moved in the direction crosswise to the feed direction A and to the movement direction C according to the results of the detection step.
In some non-limiting cases, during the adjustment step (similarly to what is described above for the mobile surface 13') the position of the mobile surface 17' is also adjusted.
In particular, the mobile surface 13' is the surface (facing the inside of the transfer chamber TC) of a belt 13.
Advantageously but not necessarily, the method also comprises a variation step, during which the area of a cross section of at least one part of the transfer chamber TC is modified, in particular modifying the shape of a deformable section 45 of the wall 10.
According to some non-limiting embodiments, the method is implemented by a machine 2 as described above. Advantageously but not necessarily, during the variation step, the area of the mentioned cross section is modified by rotating the section 47 around the substantially fixed oscillation axis 48 (crosswise to the direction A and) and the section 49 around the substantially fixed oscillation axis 49 (crosswise to the direction A and) .
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