METHOD AND PLANT FOR MANUFACTURING CERAMIC PRODUCTS

Description

[0001] The present invention generally relates to a method and a plant for manufacturing ceramic products and, in particular, a method and a plant for preparing and distributing, according to a plurality of predefined layouts, ceramic powders for the production of slabs and/or tiles.

[0002] Plants for manufacturing ceramic slabs and/or tiles that faithfully reproduce the appearance, or layout, of natural stones, such as marble and/or granite, are known from the prior art. Natural stones are in fact provided with internal striations or veining, distributed randomly within their thickness, which are highly appreciated by customers, especially when these natural stones are used as a covering material for floors, walls, worktops, etc.

[0003] The aforesaid plants typically comprise devices for feeding and metering atomized and coloured ceramic powders. These feeding and metering devices usually operate by gravity. The ceramic powders are then deposited, in a controlled and programmable way through a proper electronic control system, on a conveyor belt so that a continuous strip of ceramic powder with a predefined layout is formed. The continuous strip of ceramic powder is then sent to an accumulation and compaction device where, again by gravity, the ceramic material which is still in powder "stratifies" in a controlled manner. In this way the compacted ceramic powder can take on the final appearance of the slab and/or tile, which will be effectively and definitively formed after further operations of pressing on the ceramic material still in the powder form, cutting the ceramic material to size and final cooking.

[0004] Document WO 2020/058891 A1 discloses a method for manufacturing ceramic products according to the preamble of claim 1 and a plant for manufacturing ceramic products according to the preamble of claim 6. Another plant for manufacturing ceramic products according to the prior art is disclosed in document US 5056998 A. Document CN 109927161 A, on the other hand, discloses a method for manufacturing slabs and/or tiles starting from ceramic powders.

[0005] A first drawback of the known plants for manufacturing ceramic products can even occur in the respective ceramic powders feeding and metering device. As this feeding and metering device operates by gravity and is designed for the inlet of a large amount of powders in a limited time unit, it can be subject to clogging.

[0006] Another drawback of the known plants for manufacturing ceramic products is then due to the fact that the ceramic material to be processed, being initially formed by more or less compacted ceramic powder, can undergo deformations and/or alterations within the various devices of the system, so as to compromise the final aesthetic appearance of the finished slabs and/or tiles.

[0007] The object of the present invention is therefore to provide a method and a plant for manufacturing ceramic products, in particular a method and a plant for preparing and distributing, according to a plurality of predefined layouts, ceramic powders for producing slabs and/or tiles, which are capable of solving the aforementioned drawbacks of the prior art in an extremely simple, economical and particularly functional way.

[0008] In detail, it is an object of the present invention to provide a method and a plant for manufacturing ceramic products that are capable of improving the appearance of the slabs and/or tiles as much as possible.

[0009] Another object of the present invention is to provide a method and a plant for manufacturing ceramic products that are capable of avoiding clogging and/or other possible malfunctions of the plant due to an uncontrolled management of the powders used for manufacturing slabs and/or tiles.

[0010] These objects according to the present invention are achieved by providing a method and a plant for manufacturing ceramic products as set forth in the independent claims. Further features of the invention are highlighted by the dependent claims, which are an integral part of this description.

[0011] The features and advantages of a method and a plant for manufacturing ceramic products according to the present invention will be clearer from the following, exemplifying and non-limiting description, referring to the attached drawings, wherein:

Figure 1 is a perspective view of a preferred embodiment of a plant for manufacturing ceramic products according to the present invention;

Figure 2 is a sectional view showing a component of the plant of Figure 1, designed to carry out a step of feeding the powders in the method for manufacturing ceramic products according to the present invention;

Figures 3A, 3B and 3C are sectional views showing respective embodiments of another component of the plant of Figure 1, designed to carry out a step of micro metering the powders in the method for manufacturing ceramic products according to the present invention;

Figure 4 is a sectional view showing a further component of the plant of Figure 1, designed to carry out a step of conveying the powders in the method for manufacturing ceramic products according to the present invention;

Figure 5 is a perspective view showing a further component of the plant of Figure 1, designed to carry out a step of controlled depositing the powders in the method for manufacturing ceramic products according to the present invention;

Figure 6 is a sectional view showing further components of the plant of Figure 1, designed to carry out a step of controlled accumulating powders in the method for manufacturing ceramic products according to the present invention;

Figure 7 is a perspective view showing a further component of the plant of Figure 1, designed to carry out a step of controlling the constant maintenance of the level of powders in the method for manufacturing ceramic products according to the present invention; and

Figure 8 is a sectional view showing a further component of the plant of Figure 1, designed to carry out a step of checking the thickness of the final layer of powders that will form the ceramic products upon completion of the method for manufacturing ceramic products according to the present invention.

[0012] With reference to Figure 1, a preferred embodiment of a plant for manufacturing ceramic products according to the present invention is shown. The plant is indicated as a whole with the reference number 10. The plant 10 is designed to provide a method for manufacturing ceramic products T which sequentially comprises a plurality of operative steps.

[0013] A first operative step consists in gravity feeding a mixture of one or more ceramic powders having features and/or colours different from one another, by means of at least one feeding device 12 and along at least one substantially vertical feeding direction A (Figure 2). As shown in the sectional view of Figure 2, each feeding device 12 comprises at least one hopper 28 which is internally provided with a plurality of separator baffles 30, 32, 34, 36, 38 which, as will be better specified below, are configured to discharge the weight of the mixture of ceramic powders leaving the feeding device 12, so as to avoid clogging thereof.

[0014] Further to the feeding step, a micro metering step is provided for micro metering said ceramic powders fed by the hopper 28, by means of at least one metering device 14 controlled by at least one central processing unit 50, so as to divide said ceramic powders on the basis of predefined quality criteria. These predefined quality criteria can consist, for example, of the particle size of the ceramic powders, humidity, flowability, flow rate, etc.

[0015] Each metering device 14 is conveniently provided with a plurality of nozzles 40 whose predefined passage section is as small as possible, but is in any case suitable for gravity dropping the ceramic powders along the substantially vertical feeding direction A. The sectional views of Figures 3A, 3B and 3C show three possible embodiments of the metering device 14 and the respective nozzles 40, which are manufactured according to known technologies and are operated independently by the central processing unit 50 of the plant. 10.

[0016] According to the invention, as shown in Figures 3A, 3B and 3C, the step of micro metering the ceramic powders comprises at least one sub-step of removing those ceramic powders which do not satisfy one or more of the abovementioned predefined quality criteria. For this purpose, each metering device 14 is provided with one or more powder removal apparatuses 48, 60 arranged to remove at least part of the ceramic powders, such as too fine powders, from the main flow of ceramic powders passing through each nozzle 40. For example, as shown in Figure 3B, the powder removal apparatus 48, 60 of the metering device 14 can comprise one or more micro-filters 48, operatively associated with a respective nozzle 40 through which the main flow of ceramic powders passes, and one or more suction pumps 60, designed to suck the too fine powders through each micro-filter 48.

[0017] Each metering device 14 can also be preferably provided with one or more shut-off valves 64, such as pinch valves. Each of these shut-off valves 64 can be installed along a respective nozzle 40 (Figure 3A), to intercept the main flow of the ceramic powders, and/or at one or more ducts 66 (Figure 3B) arranged for extracting the too fine powders from this main flow of ceramic powders.

[0018] Further to the ceramic powders micro metering step, a dispensing and depositing step is provided, by means of at least one dispensing device 16 (Figure 4), for dispensing and depositing said ceramic powders on a first transport device 18 which is substantially flat and movable along a substantially horizontal feeding direction B, so as to obtain a first layer L of ceramic powders having surface chromatic effects. The dispensing device 16 is positioned downstream of the metering device 14.

[0019] As shown in Figure 4, said step of dispensing and depositing the ceramic powders comprises at least one sub-step of conveying, by means of at least one conveying element 24 of said dispensing device 16, said ceramic powders along a single dispensing direction F starting from a plurality of separate and distinct dispensing directions D, E. In this way, the ceramic powders can be dispensed on the first transport device 18 along the single dispensing direction F, in order to better control the flow rate of these ceramic powders by the central processing unit 50 of the plant 10, as well as to increase the characterization of the surface chromatic effects that can be seen on the first layer L of the ceramic powders.

[0020] The first transport device 18 transfers the first layer L of powdered ceramic material towards the subsequent operative accumulation and compaction step. In this operative step, the first layer L of powdered ceramic material is accumulated and compacted by means of at least one accumulation and compaction device 20 controlled by the central processing unit 50, along an accumulation and compaction direction C, which, preferably and as shown in Figure 6, is substantially vertical. In this way a second layer CL of compacted ceramic powders is obtained, which has both surface chromatic effects and chromatic effects in the thickness.

[0021] Further to the accumulation and compaction step, the second layer CL of ceramic powders compacted by the accumulation and compaction device 20 is transferred by means of a second transport device 42 which is substantially flat and movable along the same substantially horizontal feeding direction B as the first transport device 18, towards the subsequent operative pressing step. This pressing step is obtained by means of at least one pressing device 22 which compresses the second layer CL of compacted ceramic powders, so as to reduce its thickness and obtain the ceramic products T in the form of one or more slabs and/or tiles.

[0022] According to the invention, the step of feeding the mixture of ceramic powders comprises at least one sub-step of feeding this mixture of ceramic powders along one or more feeding directions A1, A2, A3 which are inclined according to respective predefined angles with respect to the substantially vertical feeding direction A, so as to relieve the vertical load of this mixture of ceramic powders which weighs on the nozzles 40 of the metering device 14, which is located below the feeding device 12.

[0023] The mixture of ceramic powders is diverted along one or more feed directions A1, A2, A3 which are inclined with respect to the substantially vertical feeding direction A: this diversion is due to the particular and innovative internal conformation of the hopper 28. In addition to one or more substantially vertical separator baffles 30, 32, this hopper 28 is in fact internally also provided with further separator baffles 34, 36, 38, which are operatively associated with the substantially vertical separator baffles 30, 32 and/or with the walls of the hopper 28 and which, as shown in Figure 2, are oriented along respective directions A1, A2, A3 which are inclined according to respective predefined angles with respect to the substantially vertical feed direction A.

[0024] Again according to the invention, the step of dispensing and depositing the ceramic powders on the first transport device 18 comprises at least one sub-step of separating these ceramic powders along a plurality of channels longitudinal and parallel to the feeding direction B of the first transport device 18. In this way the dispersion by falling of the ceramic powders is avoided, while maintaining the characterization of the surface chromatic effects on the first layer L of the ceramic powders and set through the central processing unit 50 of plant 10.

[0025] The ceramic powders are separated due to the fact that the first transport device 18 consists of a closed loop conveyor belt, the transport surface of which comprises (see Figure 5) a plurality of longitudinal protrusions 44, i.e., oriented along the feeding direction B, interspersed by a corresponding plurality of longitudinal grooves 46, also oriented along the feeding direction B. Preferably, both the longitudinal protrusions 44, and the corresponding longitudinal grooves 46 have a cross-sectional triangular or pyramidal shape, i.e. a section perpendicular to the feeding direction B. The particular conformation of the transport surface of the first transport device 18, with alternating longitudinal protrusions 44 and longitudinal grooves 46, helps to contain the ceramic powders leaving the nozzles 40 of the metering device 14 and the conveying element 24 of the dispensing device 16, avoiding its dispersion by falling and thus maintaining a good characterization of the layout of the slab and/or tile T in the process of formation. It should also be noted that the first layer L of the powdered ceramic material deposited on the first transport device 18 has a very reduced thickness, so as to obtain a greater characterization of the layout even in the subsequent accumulation and compaction step, adapted to form the second layer CL of compacted ceramic powders.

[0026] The step of accumulating and compacting the first layer L of powdered ceramic material comprises at least one sub-step of dynamic variation of the accumulation and compaction direction C with respect to a substantially vertical plane, so as to control the formation of both the surface chromatic effects, and the chromatic effects in the thickness of the second layer CL of compacted ceramic powders. For this purpose, the accumulation and compaction device 20 consists of at least one hopper (or "drawer") with a substantially vertical development, sized to allow therein an adequate flow of the powders which form the first layer L of ceramic material during the respective stratification step leaving the first transport device 18.

[0027] As shown in Figure 6, an important aspect is linked to the fall height of the ceramic powders which form the first layer L of ceramic material inside the hopper 20. This determines the success of the layout of the slab and/or tile T in the process of formation, especially when this layout reproduces the typical veining of marble throughout the thickness of this slab and/or tile T. The lower the fall height of the ceramic powders, the higher the resolution of the layout, as it avoids a mixing of the ceramic powders due to a possible excessively high drop height.

[0028] To obtain the dynamic variation of the accumulation and compaction direction C of the powdered ceramic material, the hopper 20 is conveniently provided with at least one pivoting mechanism 52 configured to rotate this accumulation and compaction device 20 about a horizontal axis which is substantially perpendicular with respect to said feeding direction B. In this way, not only is the dynamic variation of the accumulation and compaction direction C of the powdered ceramic material with respect to a substantially vertical plane, but also a variation of the angle α (Figure 8) between the substantially horizontal plane on which said first transport device 18 lies and the plane passing through said accumulation and compaction device 20 at the respective upper loading opening 54 are obtained. An angle α less than 90°, in fact, helps to improve control of the formation of both the surface chromatic effects, and the chromatic effects in the thickness of the second layer CL of compacted ceramic powders.

[0029] The step of accumulation and compaction of the first layer L of powdered ceramic material can also comprise at least one sub-step of controlling, by means of at least one control sensor 26 for controlling the hopper 20, the quantity of powdered ceramic material contained inside this hopper 20. The control sensor 26 is preferably positioned at the upper loading opening 54 of the hopper 20.

[0030] Preferably, the hopper 20 can be provided with at least one arch shaped lower unloading opening 56, placed at the second transport device 42 (Figure 8). The radius of curvature of this arch shaped lower unloading opening 56 is preferably equal to 2.5 times the average thickness S of the passage section for the passage of the ceramic powders inside the hopper 20, for the purpose of a correct positioning of the second layer CL of compacted ceramic powders on the second transport device 42.

[0031] Again preferably, as shown in Figure 8, the hopper 20 can also be provided with at least one gate 62 designed to selectively close the respective arch shaped lower unloading opening 56 under certain operating conditions of the plant 10. This gate 62, for example, can be kept closed during the step of the first filling of the hopper 20 with the powders coming from the first layer L of ceramic material transported by the first transport device 18. Once a predefined quantity of powdered ceramic material has been reached inside the hopper 20, in which this predefined quantity can be indicated for example by the control sensor 26, the gate 62 can be opened to allow the formation of the second layer CL of compacted ceramic powders on the second transport device 42.

[0032] Outgoing from the second transport device 42, the second layer CL of compacted ceramic powders, provided with chromatic effects on the surface and/or the thickness thereof, pre-set by the central processing unit 50 of the plant 10, undergoes the pressing step for the formation of ceramic products T in the form of one or more slabs and/or tiles. This pressing step can take place at a third transport device 58, yet oriented along the same substantially horizontal feeding direction B of the first two transport devices 18 and 42. In a per se known manner, this pressing step can be followed by at least one subsequent cooking step, in proper furnaces (not shown), of the ceramic products T in the form of one or more slabs and/or tiles, as well as a possible cut to size of the ceramic products T.

[0033] It has thus been seen that the method and the plant for manufacturing ceramic products according to the present invention achieve the previously highlighted objects.

Claims

1. A method for manufacturing ceramic products (T) comprising in sequence the steps of:

- gravity feeding a mixture of two or more ceramic powders having different features and/or colours from one another, by means of at least one feeding device (12) and along at least one substantially vertical feeding direction (A);

- micro metering said ceramic powders, by means of at least one metering device (14) controlled by at least one central processing unit (50), so as to divide said ceramic powders on the basis of predefined quality criteria;

- dispensing and depositing, by means of at least one dispensing device (16) positioned downstream of said at least one metering device (14), said ceramic powders on a first transport device (18) which is substantially flat and movable along a substantially horizontal feeding direction (B) and consists of a closed loop conveyor belt, so as to obtain a first layer (L) of ceramic powders having surface chromatic effects;

- accumulating and compacting said first layer (L) of powdered ceramic material along an accumulation and compaction direction (C), by means of at least one accumulation and compaction device (20) controlled by said central processing unit (50), so as to obtain a second layer (CL) of compacted ceramic powders having both surface chromatic effects, and chromatic effects in the thickness; and

- pressing said second layer (CL) of compacted ceramic powders, by means of at least one pressing device (22), so as to obtain said ceramic products (T) in the form of one or more slabs and/or tiles,

wherein said dispensing and depositing step comprises at least one sub-step of separating said ceramic powders along a plurality of channels which are longitudinal and parallel to said feeding direction (B), so as to avoid dispersion by falling of said ceramic powders and to maintain the characterization of said surface chromatic effects, the method being characterized in that:

- said feeding step comprises at least one sub-step of feeding said ceramic powders along one or more feeding directions (A1, A2, A3) which are inclined according to respective predefined angles with respect to said substantially vertical feeding direction (A), so as to relieve the vertical load of said ceramic powders which weighs on said metering device (14);

- said separating sub-step is implemented by said first transport device (18), said closed loop conveyor belt having a transport surface with a plurality of longitudinal protrusions (44) interspersed by a plurality of longitudinal grooves (46), all oriented along said feeding direction (B);

- said accumulation and compaction step comprises at least one sub-step of dynamic variation of said accumulation and compaction direction (C) with respect to a substantially vertical plane, so as to control the formation of both said surface chromatic effects, and said chromatic effects in the thickness of said second layer (CL) of compacted ceramic powders; and

- said step of micro metering the ceramic powders comprises at least one sub-step of removing those ceramic powders which do not satisfy one or more of said predefined quality criteria, said removing sub-step being implemented by one or more powder removal apparatuses (48, 60) of said metering device (14).

2. The method according to claim 1, wherein said step of dispensing and depositing the ceramic powders comprises at least one sub-step of conveying, by means of at least one conveying element (24) of said dispensing device (16), said ceramic powders along a single dispensing direction (F) starting from a plurality of separate and distinct dispensing directions (D, E), so that said ceramic powders are dispensed on said first transport device (18) along said single dispensing direction (F).

3. The method according to claim 1 or 2, wherein said accumulation and compaction step comprises at least one sub-step of variation of the angle (α) between the substantially horizontal plane on which said first transport device (18) lies and the plane passing through said accumulation and compaction device (20) at the respective upper loading opening (54), wherein an angle (α) less than 90° helps to improve control of the formation of both said surface chromatic effects and said chromatic effects in the thickness of said second layer (CL) of compacted ceramic powders.

4. The method according to any claims 1 to 3, wherein said accumulation and compaction step comprises at least one sub-step of controlling, by means of at least one control sensor (26) for controlling said accumulation and compaction device (20), the quantity of powdered ceramic material contained inside said accumulation and compaction device (20).

5. The method according to any claims 1 to 4, further comprising, after said pressing step, at least one step of cooking said ceramic products (T) in the form of one or more slabs and/or tiles.

6. A plant (10) for manufacturing ceramic products (T) by implementing the method according to any claims 1 to 5, the plant (10) comprising:

- at least one central processing unit (50);

- at least one feeding device (12), which is arranged for gravity feeding a mixture of two or more ceramic powders having different features and/or colours from one another and comprises at least one hopper (28);

- at least one metering device (14), which is designed for carrying out the micro metering of said ceramic powders and is provided with a plurality of nozzles (40) having a predefined passage section suitable for gravity dropping said ceramic powders along a substantially vertical feeding direction (A);

- a first transport device (18), which is substantially flat and movable along a substantially horizontal feeding direction (B) and which consists of a closed loop conveyor belt;

- at least one dispensing device (16) for dispensing said ceramic powders, which is positioned downstream of said at least one metering device (14) and which is designed for carrying out the dispensing and deposition of a first layer (L) of said ceramic powders on said first transport device (18);

- at least one accumulation and compaction device (20), which is arranged for carrying out accumulation and compaction of said ceramic powders along an accumulation and compaction direction (C) into a second layer (CL) of compacted ceramic powders having both surface chromatic effects and chromatic effects in the thickness;

- a second transport device (42), which is substantially flat and movable along said substantially horizontal feeding direction (B) and on which said second layer (CL) of compacted ceramic powders coming out of said accumulation and compaction device (20) is transferred; and

- at least one pressing device (22), which is designed to press said second layer (CL) of compacted ceramic powders, so as to obtain said ceramic products (T) in the form of one or more slabs and/or tiles,

the plant (10) being characterized in that said at least one dispensing device (16) is provided with at least one element (24) for conveying said ceramic powders along a single feeding direction (F) starting from a plurality of separated and distinct feeding directions (D, E),

- wherein said hopper (28) is internally provided with both one or more substantially vertical separator baffles (30, 32), and further separator baffles (34, 36, 38) which are operatively associated with said one or more substantially vertical separator baffles (30, 32) and/or with the walls of said hopper (28), and wherein said further separator baffles (34, 36, 38) are oriented along respective directions (A1, A2, A3) which are inclined according to respective predefined angles with respect to said substantially vertical feeding direction (A);

- wherein the transport surface of said closed loop conveyor belt comprises a plurality of longitudinal protrusions (44), i.e., oriented along said feeding direction (B), interspersed by a corresponding plurality of longitudinal grooves (46), also oriented along said feeding direction (B);

- wherein said accumulation and compaction device (20) is provided with at least one pivoting mechanism (52) configured to rotate said accumulation and compaction device (20) about a horizontal axis which is substantially perpendicular with respect to said feeding direction (B), so as to cause a dynamic variation of said accumulation and compaction direction (C) with respect to a substantially vertical plane;

- wherein said metering device (14) is provided with one or more powder removal apparatuses (48, 60) arranged to remove at least part of the ceramic powders from the main flow of ceramic powders passing through each nozzle (40), namely those ceramic powders which do not satisfy one or more predefined quality criteria.

7. The plant (10) according to claim 6, wherein both said longitudinal protrusions (44), and the corresponding longitudinal grooves (46) have a triangular or pyramidal shape in cross-section, i.e., a section perpendicular to said feeding direction (B).

8. The plant (10) according to claim 6 or 7, wherein said accumulation and compaction device (20) consists of a hopper equipped with at least one control sensor (26) for controlling the quantity of ceramic powders contained inside said hopper (20), said at least one control sensor (26) being preferably positioned at the upper loading (54) of said hopper (20).

9. The plant (10) according to claim 8, wherein said hopper (10) is provided with at least one arch shaped lower unloading opening (56), located at said second transport device (42), wherein the radius of curvature of said arch shaped lower unloading opening (56) is equal to 2.5 times the average thickness (S) of the passage section for the passage of the ceramic powders inside said hopper (20).

10. The plant (10) according to claim 9, wherein said hopper (10) is provided with at least one gate (62) designed to selectively close said arch shaped lower unloading opening (56) under certain operating conditions of the plant (10).

Ansprüche

1. Verfahren zum Herstellen von keramischen Produkten (T), nacheinander die folgenden Schritte umfassend:

- Schwerkraft-Zuführen einer Mischung aus zwei oder mehr keramischen Pulvern mit voneinander verschiedenen Merkmalen und/oder Farben mittels mindestens einer Zufuhrvorrichtung (12) und entlang mindestens einer im Wesentlichen vertikalen Zufuhrrichtung (A),

- Mikrobemessen der keramischen Pulver mittels mindestens einer Bemessungsvorrichtung (14), die von mindestens einer zentralen Verarbeitungseinheit (50) derart gesteuert wird, dass die keramischen Pulver auf der Grundlage vordefinierter Qualitätskriterien getrennt werden,

- Ausgeben und Ablagern der keramischen Pulver auf einer ersten Transportvorrichtung (18), die im Wesentlichen eben und entlang einer im Wesentlichen horizontalen Zufuhrrichtung (B) beweglich ist und aus einem Endlosförderband besteht, mittels mindestens einer Ausgabevorrichtung (16), die prozessabwärts der mindestens einen Bemessungsvorrichtung (14) positioniert ist, so dass eine erste Schicht (L) aus keramischen Pulvern erhalten wird, die chromatische Oberflächeneffekte aufweist,

- Ansammeln und Verdichten der ersten Schicht (L) aus pulverförmigem keramischem Material entlang einer Ansammlungs- und Verdichtungsrichtung (C) mittels mindestens einer Ansammlungs- und Verdichtungsvorrichtung (20), die von der zentralen Verarbeitungseinheit (50) gesteuert wird, so dass eine zweite Schicht (CL) aus verdichteten keramischen Pulvern erhalten wird, die sowohl chromatische Oberflächeneffekte als auch chromatische Effekte in der Dicke aufweist, und

- Pressen der zweiten Schicht (CL) aus verdichteten keramischen Pulvern mittels mindestens einer Pressvorrichtung (22), so dass die keramischen Produkte (Z) in Form einer oder mehrerer Fliesen und/oder Kacheln erhalten werden,

wobei der Schritt des Ausgebens und Ablagerns mindestens einen Teilschritt des Trennens der keramischen Pulver entlang mehrerer Kanäle umfasst, die längs und parallel zu der Zufuhrrichtung (B) liegen, so dass eine Verteilung durch Fallen der keramischen Pulver vermieden wird und die Charakteristik der chromatischen Oberflächeneffekte erhalten bleibt, wobei das Verfahren dadurch gekennzeichnet ist, dass:

- der Schritt des Zuführens mindestens einen Teilschritt des Zuführens der keramischen Pulver entlang einer oder mehreren Zufuhrrichtungen (A1, A2, A3) umfasst, die gemäß entsprechenden vordefinierten Winkeln in Bezug auf die im Wesentlichen vertikale Zufuhrrichtung (A) geneigt sind, so dass die vertikale Last der keramischen Pulver gemindert wird, die auf der Bemessungsvorrichtung (14) lasten,

- der Teilschritt des Trennens durch die erste Transportvorrichtung (18) ausgeführt wird, wobei das Endlosförderband eine Transportfläche mit mehreren längsgerichteten Vorsprüngen (44) aufweist, zwischen denen längsgerichtete Rillen (46) eingestreut sind, die alle entlang der Zufuhrrichtung (B) ausgerichtet sind,

- der Schritt des Ansammelns und Verdichtens mindestens einen Teilschritt des dynamischen Variierens der Ansammlungs- und Verdichtungsrichtung (C) in Bezug auf eine im Wesentlichen vertikale Ebene umfasst, so dass das Bilden von sowohl der chromatischen Oberflächeneffekte als auch der chromatischen Effekte in der Dicke der zweiten Schicht (CL) aus verdichteten keramischen Pulvern gesteuert wird, und

- der Schritt des Mikrobemessens der keramischen Pulver mindestens einen Teilschritt des Entfernens derjenigen keramischen Pulver umfasst, die eines oder mehrere der vordefinierten Qualitätskriterien nicht erfüllen, wobei der Teilschritt des Entfernens durch eine oder mehrere Pulverentfernungsapparate (48, 60) der Bemessungsvorrichtung (14) ausgeführt wird.

2. Verfahren nach Anspruch 1, wobei der Schritt des Ausgebens und Ablagerns der keramischen Pulver mindestens einen Teilschritt des Beförderns der keramischen Pulver entlang einer einzigen Ausgaberichtung (F) ausgehend von mehreren getrennten und verschiedenen Ausgaberichtungen (D, E) umfasst, mittels mindestens eines Förderelements (24) der Ausgabevorrichtung (16), so dass die keramischen Pulver auf der ersten Transportvorrichtung (18) entlang der einzigen Ausgaberichtung (F) ausgegeben werden.

3. Verfahren nach Anspruch 1 oder 2, wobei der Schritt des Ansammelns und Verdichtens mindestens einen Teilschritt des Variierens des Winkels (α) zwischen der im Wesentlichen horizontalen Ebene, auf der die Transportvorrichtung (18) liegt, und der Ebene, welche durch die Ansammlungs- und Verdichtungsvorrichtung (20) verläuft, an der entsprechenden oberen Ladeöffnung (54) umfasst, wobei ein Winkel (α) kleiner als 90° dabei hilft, das Steuern des Bildens von sowohl chromatischen Oberflächeneffekten als auch chromatischen Effekten in der Dicke der zweiten Schicht (CL) aus verdichteten keramischen Pulvern zu verbessern.

4. Verfahren nach einem der Ansprüche 1 bis 3, wobei der Schritt des Ansammelns und Verdichtens mindestens einen Teilschritt des Steuerns der Menge des pulverförmigen keramischen Materials, das in der Ansammlungs- und Verdichtungsvorrichtung (20) enthalten ist, mittels mindestens eines Steuersensors (26) zum Steuern der Ansammlungs- und Verdichtungsvorrichtung (20) umfasst.

5. Verfahren nach einem der Ansprüche 1 bis 4, nach dem Schritt des Pressens ferner mindestens einen Schritt des Wärmebehandelns der keramischen Produkte (T) in Form von einer oder mehreren Fliesen und/oder Kacheln umfassend.

6. Anlage (10) zum Herstellen von keramischen Produkten (T) durch Ausführen des Verfahrens nach einem der Ansprüche 1 bis 5, wobei die Anlage (10) Folgendes umfasst:

- mindestens eine zentrale Verarbeitungseinheit (50),

- mindestens eine Zufuhrvorrichtung (12), die für ein Schwerkraft-Zuführen einer Mischung aus zwei oder mehr keramischen Pulvern mit voneinander verschiedenen Merkmalen und/oder Farben angeordnet ist und die mindestens einen Zufuhrschacht (28) umfasst,

- mindestens eine Bemessungsvorrichtung (14), die für das Ausführen des Mikrobemessens der keramischen Pulver gestaltet und mit mehreren Düsen (40) ausgestattet ist, die einen vordefinierten Durchlaufabschnitt aufweisen, der für das Schwerkraft-Fallen der keramischen Pulver entlang einer im Wesentlichen vertikalen Zufuhrrichtung (A) geeignet ist,

- eine erste Transportvorrichtung (18), die im Wesentlichen eben und entlang einer im Wesentlichen horizontalen Zufuhrrichtung (B) beweglich ist und die aus einem Endlosförderband besteht,

- mindestens eine Ausgabevorrichtung (16) zum Ausgeben der keramischen Pulver, die prozessabwärts der mindestens einen Bemessungsvorrichtung (14) positioniert ist und die zum Ausführen des Ausgebens und Ablegens einer ersten Schicht (L) der keramischen Pulver auf der ersten Transportvorrichtung (18) gestaltet ist,

- mindestens eine Ansammlungs- und Verdichtungsvorrichtung (20), die zum Ausführen des Ansammelns und Verdichtens der keramischen Pulver entlang einer Ansammlungs- und Verdichtungsrichtung (C) zu einer zweiten Schicht (CL) aus verdichteten keramischen Pulvern angeordnet ist, die sowohl chromatische Oberflächeneffekte als auch chromatische Effekte in der Dicke aufweist,

- eine zweite Transportvorrichtung (42), die im Wesentlichen eben und entlang einer im Wesentlichen horizontalen Zufuhrrichtung (B) beweglich ist und auf der die zweite Schicht (CL) aus verdichteten keramischen Pulvern, die aus der Ansammlungs- und Verdichtungsvorrichtung (20) kommt, überführt wird, und

- mindestens eine Pressvorrichtung (22), die dafür gestaltet ist, die zweite Schicht (CL) aus verdichteten keramischen Pulvern zu pressen, so dass die keramischen Produkte (Z) in Form einer oder mehrerer Fliesen und/oder Kacheln erhalten werden, wobei die Anlage (10) dadurch gekennzeichnet ist, dass mindestens eine Ausgabevorrichtung (16) mit mindestens einem Element (24) zum Befördern der keramischen Pulver entlang einer einzigen Zufuhrrichtung (F) ausgehend von mehreren getrennten und verschiedenen Ausgaberichtungen (D, E) gestaltet ist,

- wobei der Zufuhrschacht (28) im Inneren mit sowohl einem oder mehreren im Wesentlichen vertikalen Trennlenkblechen (30, 32) als auch weiteren Trennlenkblechen (35, 36, 38) ausgestattet ist, die funktionsfähig dem einen oder den mehreren im Wesentlichen vertikalen Trennlenkblechen (30, 32) und/oder den Wänden des Zufuhrschachts (28) zugeordnet sind, und wobei die weiteren Trennlenkbleche (34, 36, 38) entlang entsprechenden Richtungen (A1, A2, A3) ausgerichtet sind, die gemäß entsprechenden vordefinierten Winkeln in Bezug auf die im Wesentlichen vertikale Zufuhrrichtung (A) geneigt sind,

- wobei die Transportfläche des Endlosförderbandes mehrere längsgerichtete, d. h. entlang der Zufuhrrichtung (B) ausgerichtete, Vorsprünge (44) umfasst, zwischen denen entsprechende mehrere längsgerichtete Rillen (46) eingestreut sind, die ebenfalls in der Zufuhrrichtung (B) ausgerichtet sind,

- wobei die Ansammlungs- und Verdichtungsvorrichtung (20) mit mindestens einem Schwenkmechanismus (52) ausgestattet ist, der dafür konfiguriert ist, die Ansammlungs- und Verdichtungsvorrichtung (20) um eine horizontale Achse zu drehen, die in Bezug auf die Zufuhrrichtung (B) im Wesentlichen senkrecht liegt, so dass ein dynamisches Variieren der Ansammlungs- und Verdichtungsrichtung (C) in Bezug auf eine im Wesentlichen vertikalen Ebene bewirkt wird,

- wobei die Bemessungsvorrichtung (14) mit einer oder mehreren Pulverentfernungsapparaten (48, 60) ausgestattet ist, die dafür angeordnet sind, mindestens einen Teil der keramischen Pulver von dem Hauptstrom keramischer Pulver zu entfernen, der durch jede Düse (40) verläuft, nämlich diejenigen keramischen Pulver, die eines oder mehrere der vordefinierten Qualitätskriterien nicht erfüllen.

7. Anlage (10) nach Anspruch 6, wobei sowohl die längsgerichteten Vorsprünge (44) als auch die entsprechenden längsgerichteten Rillen (46) eine dreieckige oder pyramidenförmige Querschnittsform aufweisen, d. h. in einem Schnitt senkrecht zu der Zufuhrrichtung (B).

8. Anlage (10) nach Anspruch 6 oder 7, wobei die Ansammlungs- und Verdichtungsvorrichtung (20) aus einem Zufuhrschacht besteht, der mit mindestens einem Steuersensor (26) zum Steuern der Menge der keramischen Pulver, die im Inneren des Zufuhrschachts (20) enthalten sind, ausgestattet ist, wobei der mindestens ein Steuersensor (26) vorzugsweise an der oberen Ladeöffnung (54) des Zufuhrschachts (20) positioniert ist.

9. Anlage (10) nach Anspruch 8, wobei der Zufuhrschacht (10) mit mindestens einer bogenförmigen unteren Entladeöffnung (56) ausgestattet ist, die sich an der zweiten Transportvorrichtung (42) befindet, wobei der Krümmungsradius der bogenförmigen unteren Entladeöffnung (56) gleich dem 2,5-Fachen der durchschnittlichen Dicke (S) des Durchlassabschnitts zum Durchlassen der keramischen Pulver im Inneren des Zufuhrschachts (20) ist.

10. Anlage (10) nach Anspruch 9, wobei der Zufuhrschacht (10) mit mindestens einem Schieber (62) ausgestattet ist, der dafür gestaltet ist, die bogenförmige untere Entladeöffnung (56) unter bestimmten Betriebsbedingungen der Anlage (10) wahlweise zu schließen.

Revendications

1. Procédé de fabrication des produits céramiques (T) comprenant en séquence les étapes suivantes :

- l'alimentation par gravité d'un mélange de deux ou plusieurs poudres céramiques présentant des caractéristiques et/ou des couleurs différentes les unes des autres, au moyen d'au moins un dispositif d'alimentation (12) et le long d'au moins une direction d'alimentation sensiblement verticale (A) ;

- le microdosage desdites poudres céramiques, au moyen d'au moins un dispositif de dosage (14) commandé par au moins une unité centrale de traitement (50), de manière à diviser lesdites poudres céramiques sur la base de critères de qualité prédéfinis ;

- la distribution et le dépôt, au moyen d'au moins un dispositif de distribution (16) disposé en aval dudit au moins un dispositif de dosage (14), desdites poudres céramiques sur un premier dispositif de transport (18) sensiblement plat et mobile le long d'une direction d'alimentation sensiblement horizontale (B) et constitué d'une bande transporteuse en boucle fermée, de manière à obtenir une première couche (L) de poudres céramiques ayant des effets chromatiques de surface ;

- l'accumulation et le compactage de ladite première couche (L) de matériau céramique en poudre le long d'une direction d'accumulation et de compactage (C), au moyen d'au moins un dispositif d'accumulation et de compactage (20) commandé par ladite unité centrale de traitement (50), de manière à obtenir une deuxième couche (CL) de poudres céramiques compactées présentant à la fois des effets chromatiques de surface et des effets chromatiques dans l'épaisseur ; et

- le pressage de ladite deuxième couche (CL) de poudres céramiques compactées, au moyen d'au moins un dispositif de pressage (22), afin d'obtenir lesdits produits céramiques (T) sous la forme d'une ou de plusieurs dalles et/ou carreaux,

dans lequel ladite étape de distribution et de dépôt comprend au moins une sous-étape de séparation desdites poudres céramiques le long d'une pluralité de canaux longitudinaux et parallèles à ladite direction d'alimentation (B), de manière à éviter la dispersion par chute desdites poudres céramiques et à maintenir la caractérisation desdits effets chromatiques de surface, le procédé étant caractérisé en ce que :

- ladite étape d'alimentation comprend au moins une sous-étape d'alimentation desdites poudres céramiques le long d'une ou plusieurs directions d'alimentation (A1, A2, A3) inclinées selon des angles prédéfinis respectifs par rapport à ladite direction d'alimentation sensiblement verticale (A), de manière à soulager la charge verticale desdites poudres céramiques qui pèse sur ledit dispositif de dosage (14) ;

- ladite sous-étape de séparation est mise en oeuvre par ledit premier dispositif de transport (18), ladite bande transporteuse en boucle fermée ayant une surface de transport avec une pluralité de protubérances longitudinales (44) entrecoupées par une pluralité de rainures longitudinales (46), toutes orientées le long de ladite direction d'alimentation (B) ;

- ladite étape d'accumulation et de compactage comprend au moins une sous-étape de variation dynamique de ladite direction d'accumulation et de compactage (C) par rapport à un plan sensiblement vertical, de manière à contrôler la formation desdits effets chromatiques de surface et desdits effets chromatiques dans l'épaisseur de ladite deuxième couche (CL) de poudres céramiques compactées ; et

- ladite étape de microdosage des poudres céramiques comprend au moins une sous-étape d'élimination des poudres céramiques qui ne satisfont pas à un ou plusieurs desdits critères de qualité prédéfinis, ladite sous-étape d'élimination étant mise en oeuvre par un ou plusieurs appareils d'élimination des poudres (48, 60) dudit dispositif de dosage (14).

2. Procédé selon la revendication 1, dans lequel ladite étape de distribution et de dépôt des poudres céramiques comprend au moins une sous-étape de transport, au moyen d'au moins un élément de transport (24) dudit dispositif de distribution (16), desdites poudres céramiques le long d'une direction de distribution unique (F) à partir d'une pluralité de directions de distribution séparées et distinctes (D, E), de sorte que lesdites poudres céramiques sont distribuées sur ledit premier dispositif de transport (18) le long de ladite direction de distribution unique (F).

3. Procédé selon la revendication 1 ou 2, dans lequel ladite étape d'accumulation et de compactage comprend au moins une sous-étape de variation de l'angle (α) entre le plan sensiblement horizontal sur lequel repose ledit premier dispositif de transport (18) et le plan passant à travers ledit dispositif d'accumulation et de compactage (20) au niveau de l'ouverture de chargement supérieure respective (54), dans lequel un angle (α) inférieur à 90° permet d'améliorer le contrôle de la formation desdits effets chromatiques de surface et desdits effets chromatiques dans l'épaisseur de ladite deuxième couche (CL) de poudres céramiques compactées.

4. Procédé selon l'une quelconque des revendications 1 à 3, dans lequel ladite étape d'accumulation et de compactage comprend au moins une sous-étape de contrôle, au moyen d'au moins un capteur de télécommande (26) destiné à commander ledit dispositif d'accumulation et de compactage (20), la quantité de matériau céramique en poudre contenue dans ledit dispositif d'accumulation et de compactage (20).

5. Procédé selon l'une quelconque des revendications 1 à 4, comprenant en outre, après ladite étape de pressage, au moins une étape de cuisson desdits produits céramiques (T) sous la forme d'une ou de plusieurs dalles et/ou carreaux.

6. Installation (10) destinée à la fabrication de produits céramiques (T) par la mise en oeuvre du procédé selon l'une quelconque des revendications 1 à 5, l'installation (10) comprenant :

- au moins une unité centrale de traitement (50) ;

- au moins un dispositif d'alimentation (12), conçu pour alimenter par gravité un mélange de deux ou plusieurs poudres céramiques présentant des caractéristiques et/ou des couleurs différentes les unes des autres, et comprenant au moins une trémie (28) ;

- au moins un dispositif de dosage (14), conçu pour effectuer le microdosage desdites poudres céramiques et doté d'une pluralité de buses (40) présentant une section de passage prédéfinie adaptée à la chute par gravité desdites poudres céramiques le long d'une direction d'alimentation sensiblement verticale (A) ;

- un premier dispositif de transport (18), sensiblement plat et mobile le long d'une direction d'alimentation sensiblement horizontale (B) et constitué d'une bande transporteuse en boucle fermée ;

- au moins un dispositif de distribution (16) permettant de distribuer lesdites poudres céramiques, disposé en aval dudit au moins un dispositif de dosage (14) et conçu pour effectuer la distribution et le dépôt d'une première couche (L) desdites poudres céramiques sur ledit premier dispositif de transport (18) ;

- au moins un dispositif d'accumulation et de compactage (20), conçu pour procéder à l'accumulation et au compactage desdites poudres céramiques le long d'une direction d'accumulation et de compactage en une deuxième couche (CL) de poudres céramiques compactées présentant à la fois des effets chromatiques de surface et des effets chromatiques dans l'épaisseur ;

- un deuxième dispositif de transport (42), sensiblement plat et mobile le long de ladite direction d'alimentation sensiblement horizontale (B) et sur lequel est transférée ladite deuxième couche (CL) de poudres céramiques compactées sortant dudit dispositif d'accumulation et de compactage (20) ; et

- au moins un dispositif de pressage (22), conçu pour presser ladite deuxième couche (CL) de poudres céramiques compactées, afin d'obtenir lesdits produits céramiques (T) sous la forme d'une ou plusieurs dalles et/ou carreaux,

l'installation (10) étant caractérisée en ce que ledit au moins un dispositif de distribution (16) est pourvu d'au moins un élément (24) permettant d'acheminer lesdites poudres céramiques le long d'une seule direction d'alimentation (F) à partir d'une pluralité de directions d'alimentation séparées et distinctes (D, E),

- dans laquelle ladite trémie (28) est pourvue intérieurement d'un ou plusieurs déflecteurs séparateurs sensiblement verticaux (30, 32) et d'autres déflecteurs séparateurs (34, 36, 38) associés de manière opérationnelle auxdits un ou plusieurs déflecteurs séparateurs sensiblement verticaux (30, 32) et/ou aux parois de ladite trémie (28), et dans laquelle ces autres déflecteurs séparateurs (34, 36, 38) sont orientés le long de directions respectives (A1, A2, A3) inclinées selon des angles prédéfinis respectifs par rapport à ladite direction d'alimentation sensiblement verticale (A) ;

- dans laquelle la surface de transport de ladite bande transporteuse en boucle fermée comprend une pluralité de saillies longitudinales (44), c'est-à-dire orientées le long de ladite direction d'alimentation (B), entrecoupées par une pluralité correspondante de rainures longitudinales (46), également orientées le long de ladite direction d'alimentation (B) ;

- dans laquelle ledit dispositif d'accumulation et de compactage (20) est pourvu d'au moins un mécanisme pivotant (52) configuré pour faire tourner ledit dispositif d'accumulation et de compactage (20) autour d'un axe horizontal sensiblement perpendiculaire à ladite direction d'alimentation (B), de manière à provoquer une variation dynamique de ladite direction d'accumulation et de compactage (C) par rapport à un plan sensiblement vertical ;

- dans laquelle ledit dispositif de dosage (14) est doté d'un ou plusieurs appareils d'élimination des poudres (48, 60) conçus pour éliminer au moins une partie des poudres céramiques du flux principal de poudres céramiques passant par chaque buse (40), à savoir les poudres céramiques qui ne satisfont pas à un ou plusieurs critères de qualité prédéfinis.

7. Installation (10) selon la revendication 6, dans laquelle lesdites saillies longitudinales (44) et les rainures longitudinales correspondantes (46) ont une forme triangulaire ou pyramidale en section transversale, c'est-à-dire une section perpendiculaire à la direction d'alimentation (B).

8. Installation (10) selon la revendication 6 ou 7, dans laquelle ledit dispositif d'accumulation et de compactage (20) est constitué d'une trémie équipée d'au moins un capteur de télécommande (26) permettant de contrôler la quantité de poudres céramiques contenue dans ladite trémie (20), ledit au moins un capteur de télécommande (26) étant de préférence positionné au niveau du chargement supérieur (54) de ladite trémie (20).

9. Installation (10) selon la revendication 8, dans laquelle ladite trémie (10) est pourvue d'au moins une ouverture de déchargement inférieure en forme d'arche (56), située au niveau dudit deuxième dispositif de transport (42), dans laquelle le rayon de courbure de ladite ouverture de déchargement inférieure en forme d'arche (56) est égal à 2,5 fois l'épaisseur moyenne (S) de la section de passage destinée au passage des poudres céramiques à l'intérieur de ladite trémie (20).

10. Installation (10) selon la revendication 9, dans laquelle ladite trémie (10) est pourvue d'au moins une porte (62) conçue pour fermer de manière sélective ladite ouverture de déchargement inférieure en forme d'arche (56) dans certaines conditions de fonctionnement de l'installation (10).

Drawing