A MACHINE FOR DRY DECORATION OF CERAMIC TILES, WITH A CONTROL SYSTEM FOR AN ACCUMULATION OF CERAMIC MIXTURE
Patent Information
- Application Number
- MX2022014534
- Authority / Receiving Office
- MX · MX
- Patent Type
- Patents
- Current Assignee / Owner
- Priority Date
- 2020-06-19
- Filing Date
- 2022-11-17
- Publication Date
- 2026-02-25
- Estimated Expiration
- 2041-05-21
Smart Images
Figure MX431727B0
Abstract
Description
The present invention relates to a decorating machine for dry decoration of ceramic tiles. Specifically, the invention relates to, but is not exclusively related to, the decorating machine described in disclosure no. PCT / IB2019 / 060214, the content of which is incorporated in its entirety into the following description. The aforementioned publication describes a decorating machine, invented by the same applicant, comprising a support element provided with a plurality of predetermined cavities, for example, in the form of substantially straight grooves. For instance, the support element is defined by a flexible band, closed in a loop around a closed passage. The machine further comprises a dispensing device arranged to deposit a predetermined quantity of product into one or more predetermined cavities. The dispensing device includes depositing two or more granular ceramic materials with different characteristics, such as color or grain size, in a controlled manner and into the selected cavities, to produce decoration within and on the surface of a ceramic material layer. A discharge device is configured to move cavities from a loading position, where they can receive powdered material from the dispensing device, to a discharge position, where they can discharge the powdered material. The discharge device is essentially defined by one or more motorized rollers that slide the support element. Along the path defined by the rollers, the support element has an upper section on which it slides and advances longitudinally, and along which, in the loading position, the cavities are oriented upwards, and a lower section along which the cavities are oriented downwards. In the passage from the loading position to the discharge position, the cavities (11) move from a position where they are oriented upwards to a position where they are oriented downwards.During this process, each cavity pours its contents downwards onto an underlying deposit plane. A relative movement is permitted between the support element that holds the cavities and the underlying deposit plane, allowing the material to descend from the cavity deposits and form a continuous layer comprising the decorations created by the dispensing device. The layer deposited on the deposit plane is designed to undergo pressing prior to firing the ceramic tile or slab. To help maintain the structure of the decoration, a containment barrier can be provided, arranged and configured to intercept the material discharged from the cavities, guiding or diverting its trajectory in a predetermined way. In a particularly effective configuration, this barrier comprises a pair of walls placed side by side to define a collection space. A first wall is located near the first roller, that is, near the area where the cavity discharge occurs. This first wall is designed to intercept the material discharged from the cavities, guiding or altering its trajectory within the collection space. The second wall is located upstream of the first wall with respect to the direction of cavity flow. This second wall is positioned not to interfere with the material projected forward by the cavities, but rather to contain the material intercepted by the first wall as it falls downward. Essentially, the two walls define a hopper that collects the material from the cavities and deposits it onto the settling plane. The material that accumulates within the collection space is gradually deposited onto the deposit platform and carried along by it. As it accumulates within the collection space and is gradually discharged onto the deposit platform, the material retains the decoration created by the dispensing device. The relative speed between the deposit plane and the support element is regulated so that the amount of material accumulated in the collection space remains substantially constant. This allows for highly precise control of the decoration structure and ensures that the decoration is transferred to the deposit surface with the expected configuration and definition. For example, the relative speed is regulated so that the height of the material within the collection space remains substantially constant. In addition to the advantages mentioned above, maintaining a constant height reduces the material's bounce from the support element downwards. In some cases, maintaining a constant amount of material within the storage space requires more than simply controlling the relative velocity between the support element and the deposition plane. Specifically, when the material has a non-constant grain size, or when two or more ceramic materials with significantly different grain sizes are used, significant fluctuations in the amount of accumulated material can occur. Such fluctuations can negatively impact the quality of the layer deposited on the deposition plane. bren ίη / ΖΖΠΖ / Ε / ΥΙΛΙ One objective of the present invention is to overcome the drawbacks described above. ίη / ZZΖΠZ / E / YΙΛΙ The main advantage offered by the decorating machine according to the present invention is to maintain a constant amount of material within the storage space, even in the presence of one or more ceramic materials with non-constant or different grain sizes. Additional features and advantages of the present invention will become more apparent from the following detailed description of one embodiment of the invention, which is illustrated by a non-limiting example in the accompanying figures, where: Figure 1 shows a schematic symmetric perspective view of a part of the machine according to the present invention; Figure 2 shows a side view of the machine in Figure 1; Figure 3 shows a schematic symmetric perspective view and a partially cross-sectional view of a machine component; Figure 4 shows a cross-sectional view of the component in Figure 3; Figure 5 shows a cross-sectional view of an alternative embodiment of the component in Figure 4; Figure 6 shows a second cross-sectional view of the component in Figure 5; Figure 7 shows a schematic side view of the machine according to the present invention; Figure 8 shows a top view of the machine in Figure 7; Figure 9 shows an enlarged view of area III of Figure 7; Figure 10 shows an enlarged view of area V in Figure 7; Figure 11 schematically shows a semi-processed element that can be obtained with the machine according to the present invention. The machine according to the present invention comprises a dispensing unit (D) arranged to dispense, in a controlled manner, a ceramic compound in granular or powder form. The ceramic compound may consist of two or more different ceramic materials. The dispensing unit (D) is arranged to deposit a layer of ceramic compound onto an underlying depositing plane (50). This layer is designed to be pressed to create a compact slab, which can then be ignited to transform it into a ceramic slab. To obtain the laying of a ceramic layer, the distribution unit (D) and the deposit plane (50) are in relative motion along a longitudinal direction (Y) through means that will be described below. In a preferred, but not exclusive, embodiment, the dispensing unit (D) comprises a dispensing device (E). The dispensing device (E) comprises two or more dispensing nozzles (N), each of which can dispense a ceramic material or a mixture of predetermined ceramic materials, for example, of a different color and / or shade and / or grain size. Preferably, the various nozzles (N) are aligned to form a bar arranged parallel to a transverse direction (Z), perpendicular or inclined with respect to the longitudinal direction (Y). Therefore, the dispensing device (E) is capable of depositing material onto a depositing face parallel to the transverse direction (Z). Two or more dispensing devices (E), structured as described above, can be arranged sequentially along the longitudinal (Y) direction, side by side, similar to the print bars of an inkjet printer of the type typically used for decorating ceramic tiles. Each dispensing device can be loaded with a ceramic or composite material with predetermined characteristics. Controlled activation of the dispensing devices (E) and their respective dispensing nozzles (N) allows the ceramic composite to be supplied in a programmed manner and according to predetermined structures, for example, to create a layer (C) comprising a decoration (V) in the form of veins or striations of different colors and / or shades, as schematically shown in Figure 11.Preferably, the decoration (V) extends at least partially within the thickness of the layer (C) of the ceramic compound. The formation of a particular structure and / or decoration by the dispensing device (D) is substantially similar to that achieved by an inkjet printer. In short, the image or decoration is obtained through a controlled supply of ceramic compound by the dispensing nozzles (N) of the dispensing unit (D), in a manner similar to how an inkjet printer creates an image through a controlled supply of liquid dye by its nozzles. Specifically, the image or decoration to be created is broken down into a series of pixel volumes, each of which is formed by a predetermined amount of a ceramic compound. The supply of the predetermined amount of the ceramic compound designed to form a specific pixel is delegated to one or more dispensing nozzles (N) that are activated, for this purpose, in a predetermined sequence. Each dispensing nozzle (N) is equipped with digitally controlled shut-off devices to open and close, thereby allowing the passage of the relevant ceramic material. Control of each dispensing nozzle (N) is provided by a control module. This control module can also be designed to control the other devices that are part of the machine according to the present invention. As is well known in the art, the control module referred to in this description and in the following claims is generically described as a single unit, but in fact, it may be provided with different functional modules (memory modules or operation modules), each responsible for controlling a specific device or cycle of operations. In short, the control module may consist of a single electronic device programmed to perform the described functions, and the different functional modules may correspond to hardware and / or routine software programs that are part of the programmed device. Alternatively or additionally, these functions may be performed by a plurality of electronic devices on which the aforementioned functional modules may be distributed.The units may also rely on one or more processors to execute the instructions stored in the memory modules. Furthermore, the aforementioned units and functional modules may be distributed across different local or remote computers based on the network architecture in which they reside. The machine according to the present invention comprises a storage container (F) interposed between the dispensing device (D) and the depositing surface (50) for storing a certain quantity of ceramic compound supplied by the dispensing device (D). The storage container (F) comprises a discharge opening (O) arranged to allow the deposit of the ceramic compound onto the depositing surface (50). Before the depositing plate (50) is placed, the ceramic compound supplied by the dispensing device (50) passes through the storage container (F). Therefore, the transfer to the depositing plate (50) is not direct; instead, the ceramic compound temporarily accumulates within the storage container (F) before the depositing plate (50) is placed. When accumulated in the storage container (F), the ceramic compound maintains the structure and / or decoration prepared in a controlled manner by means of the distribution device (D). In other words, the interposition of the storage container (F) between the distribution unit (D) and the deposit plane (50) promotes the maintenance of the decoration structure created with the distribution device (D). To prevent the ceramic compound within the storage container (F) from deforming the structure and / or decoration prepared by the dispensing device (D), it is also important that the amount of ceramic compound collected within the storage container (F) remains substantially constant over time, and specifically, that the ceramic compound maintains a uniform level within the storage container (F). In fact, local differences in the grain size of the ceramic compound, due, for example, to the presence of granules or particles of different sizes or shapes, can cause a local difference in the fluidity of the ceramic compound.Such different fluidity can cause different flow rates of the ceramic compound within the storage container (F) and, in this way, a deformation of the structure and / or decoration prepared by the distribution device (D). To prevent this from happening, the machine according to the present invention comprises one or more sensors (S) connected to the aforementioned control module, which is responsible, among other things, for controlling the dispensing unit (D). The sensors (S) are arranged to detect a significant parameter of the amount of ceramic compound contained in the storage container (F) and to process a corresponding measurement signal. Preferably, but not exclusively, at least one sensor (S) is arranged to measure the level reached by the ceramic compound within the storage container (F), understood as the height reached by the ceramic compound with respect to the discharge opening (O). In an additional solution, at least one sensor (S) is arranged to measure the weight of at least a portion of the ceramic compound within the storage container (F). It is obviously possible to use sensors simultaneously arranged to measure the level and sensors arranged to measure the weight. The various sensors (S) can be positioned to allow the measurement of the respective relevant parameter. For example, in the illustrated embodiment, the sensors (S) are placed on a front wall of the storage container (F) and are arranged to measure the level.In the preferred machine mode, several sensors (S) are included, which are arranged to measure the level of the ceramic compound. As previously mentioned, each dispensing nozzle (N) is equipped with a shut-off device, which can be activated between a flow setting, in which the supply of a ceramic material is determined, and a stop setting. Each shut-off device is controlled by the control module independently of the other shut-off devices. The control module is configured to regulate the supply of ceramic compound by the distribution unit (D) based on the measurement signal received from the sensors (S), in order to maintain a desired quantity of ceramic compound within the container (F). Preferably, the control module is configured to maintain a predetermined level of ceramic compound within the storage container (F). Specifically, the control module is designed to instruct an increase or decrease in the flow rate of ceramic material, respectively, in case the Ln / Zznz / E / YIAI blen one or more of the following parameters: the frequency of the opening / closing command of the shutter device of each dispensing nozzle (N); the duration of the open / close command; the current intensity of the open / close command signal; the voltage of the open / close command signal. In general, varying only one of the parameters mentioned above, while keeping the others constant, causes a change in the flow rate delivered by the dispensing nozzle (N). By simultaneously and in a coordinated manner varying two or more of the parameters mentioned above, it is also possible to achieve a more or less rapid change in the flow rate delivered by the dispensing nozzle (N). In one possible configuration, the shut-off devices can be activated via pneumatic control between flow and stop settings. In this configuration, the control module is designed to regulate the pneumatic control for each shut-off device, allowing for the variation of one or more of the parameters mentioned above with reference to the pneumatic control of each device. In general, the control module regulates the amount of ceramic compound dispensed by the distribution unit (D) based on the measurement signal received by the sensor(s) (S). Therefore, it is possible to regulate or maintain the amount of ceramic compound collected in the storage container (F) at a predetermined value, selected based on the grain size characteristics of the ceramic compound and the desired decoration. The storage container (F) comprises a first wall (33a) and a second wall (33b), which define a collection space (33c). The first wall (33a) is arranged and configured to intercept the material coming from the distribution unit (D) to guide or change its trajectory within the collection space (33c). The second wall (33b) is located upstream of the first wall (33a) with respect to the direction of relative movement between the storage container (F) and the deposit plane (D). The second wall is positioned to contain the material that is intercepted by the first wall (33a) and falls downwards. For example, the sensors (S) are associated with the first wall (33a). The collection space (33c) is further delimited by two additional transverse walls, not shown, joining the walls (33a, 33b). Preferably, the two walls (33a, 33b) have an inclination close to the vertical, to limit the internal flow of the material. bren ίη / ΖΖΠΖ / Ε / ΥΙΛΙ Essentially, in the illustrated mode, the two walls (33a,33b) define a hopper that collects the material coming from the distribution unit (D) and deposits it on the deposit plane (50). The discharge opening (O) is delimited by the lower edges of the walls that define the container (F). Specifically, the first wall (33a) has a lower edge (E) that is raised a certain height above the deposit plane (50). The material accumulated within the collection space (33c) is progressively deposited onto the deposit plane (50) and carried forward by it, passing under the lower edge (T), which also allows the upper surface of the continuous layer (C) to be leveled. Preferably, the second wall (33a) has a lower edge close to the deposit plane (50), at a height to prevent any material from passing through. As it accumulates within the collection space (33) and is progressively discharged onto the deposit plane (50), the material maintains the structure of the decoration (V) intended to be applied to the layer (C). Precise control of the amount of ceramic compound within the container (F), obtained thanks to the sensors (S) and the interaction between the latter, the control module and the distribution unit (D), allows the decoration structure (V) to be maintained with greater precision and to transfer the decoration (V) with the expected configuration and definition on the deposit plane (50). Figures 3, 4, and 5 schematically illustrate a possible embodiment of the dispensing nozzle (N), in which a pneumatic control is included to activate the flow and stop settings. The dispensing nozzle (N) comprises a dispensing channel (2a) provided with a longitudinal axis (X). In the embodiment shown, the dispensing channel (2a) is centrally symmetric with respect to the longitudinal axis (X). Preferably, but not necessarily, the dispensing channel (2a) has a circular cross-section in a plane perpendicular to the longitudinal axis (X), but it could be provided with an oval or ellipsoidal cross-section. However, the dispensing channel (2a) could have a different shape; for example, it could be prismatic, or it could have a quadrangular or polygonal outline in a plane perpendicular to the longitudinal axis (X). The dispensing channel has an inlet opening (21) for feeding the product, and an outlet opening (22) for dispensing the product. Preferably, the dispensing channel (2a) is arranged so that the longitudinal axis has an inclination that allows the product to flow by gravity from the inlet opening (21) to the outlet opening (22). For example, the dispensing channel (2a) is arranged with the longitudinal axis (X) oriented vertically. The inlet opening (21) can be connected to a tank or other device to feed the product. In the embodiment shown, the outlet opening (22) has a quadrangular outline in a cross-sectional plane perpendicular to the longitudinal axis (X). Furthermore, the outlet opening (22) is positioned at the end of an outlet section (22a) of the dispensing channel (2a) that diverges towards the outlet opening (22). However, other shapes are possible for both the outlet opening (22) and the outlet section (22a), such as a cylindrical or truncated conical shape. The embodiment shown in the figures offers the advantage of allowing multiple outlet openings (22) to be arranged side-by-side in a compact configuration. The dispensing device according to the present invention comprises suction means arranged to retain, by command, at least a portion of the product within the dispensing channel (2a), in order to form an accumulation that obstructs the dispensing channel (2a) and prevents the flow of the product. Essentially, the suction means are structured to cause an accumulation or stagnation of the product which, by increasing the friction between the particles that make up the product, causes a blockage and obstructs the dispensing channel (2a). The suction means according to the present invention offer the important advantage of not compressing or crushing the product. In fact, the product is trapped inside the dispensing channel (2a) primarily through the mutual friction of the particles. This is particularly advantageous, for example, because the product is atomized ceramic, which, as is known, is composed of hollow, spherical particles. The advantage of not compressing or crushing the product is also important when dealing with a particularly abrasive product. In the illustrated embodiment, the suction means are connected to the dispensing channel (2a). Upon activation, the suction means attract and retain at least a portion of the product within the dispensing channel (2a). For example, the suction means retain at least a portion of the product that is in contact with or near at least one inner surface (2c) of the dispensing channel (2a), forming an accumulation that obstructs the dispensing channel (2a). As noted earlier, the product retained in contact with the inner surface (2c) of the dispensing channel (2a) reduces the channel's flow area, forming the accumulation or blockage that prevents product flow. Deactivation of the suction means releases the product, allowing it to resume flow along the dispensing channel (2a). In summary, the suction means are arranged to produce a negative pressure that communicates with the dispensing channel (2a). For this purpose, the suction means comprise, for example, a vacuum pump, or a circuit comprising a Venturi tube that communicates with the dispensing channel (2a). Other means and devices capable of producing a negative pressure are also suitable for this purpose. In the illustrated embodiment, the dispensing device comprises one or more suction openings (23) formed through a wall of the dispensing channel (2a) and connected to the suction means. In the embodiment shown, the device comprises a suction opening (23) formed through the wall delimiting the dispensing channel (2a). The suction opening (23) opens onto the inner surface (2c) of the dispensing channel (2a). In a possible embodiment, not shown, the dispensing device may be provided with a plurality of suction openings (23), in the form of micro-holes or small-diameter holes, formed through the wall of the dispensing channel (2a), which open onto the inner surface (2c) of the dispensing channel. The suction openings (23) present are connected to the suction means. Under normal product flow conditions through the dispensing channel (2a), activation of the suction means creates a suction effect, drawing the product towards the suction opening (23). This attracts and maintains contact with or near the inner surface (2c) of the dispensing channel (2a), forming an accumulation that obstructs the channel (2a). Deactivation of the suction means releases the product accumulation, allowing flow to resume. Negative pressure values can range from 100mb to 400mb. Preferably, a filter (A) is placed between each of the suction openings (23) and the dispensing channel (2a). The filter (A) prevents the product from flowing through the suction opening (23). In the presence of negative pressure or suction, i.e., when the suction medium is activated, the product adheres to the filter (A). In one possible embodiment, the filter (A) defines at least a portion of the dispensing channel wall (2a), or defines a portion of the inner surface (2c) of the dispensing channel. For example, if the dispensing channel (2a) has a prismatic shape, the filter (A) may be made in a flat shape and define a portion of the dispensing channel wall in which the suction opening (23) is located. This applies to each suction opening (23) present. In the absence of the filter (A), the product is retained in contact with the inner surface (2c) of the dispensing channel (2a). In the presence of the filter (A), the product is retained at least partially in contact with the surface of the filter (A). The product retained on the surface of the filter (A) is therefore located close to the inner surface (2c) of the dispensing channel (2a); that is, the filter (A) is interposed between the product and the inner surface (2c) of the dispensing channel (2a). The filter (A) can have several known structures. The filter structure must be selected according to the characteristics of the product to be dispensed; that is, the filter must be capable of retaining the particles or granules of the product to be dispensed. bren ίη / ΖΖΠΖ / Ε / ΥΙΛΙ In the embodiment shown, where the dispensing channel (2a) is centrally symmetrical with respect to the longitudinal axis (X), the filter (A) has a tubular shape and is inserted into the dispensing channel (2a). The filter (A) internally delimits a passage (B), i.e., a hole, which defines at least a section of the dispensing channel (2a). The filter (A) is positioned over the suction opening (23). Additional suction openings (23) may be located in the section of the dispensing channel (2a) occupied by the filter (A). In this mode, the product normally flows along the longitudinal axis (X), through the defined passage (B) inside the filter (A) along the dispensing channel (2a). Upon activation of the suction media, the material adheres to and is held in the passage (B) in contact with the filter (A), substantially the area of the suction opening (23) and any other suction openings (23) present. In the embodiment shown, the dispensing device comprises an annular chamber (25) concentric with the filter (A) and connected to the suction means. As shown in Figure 2, the annular chamber (25) is defined in a wall of the dispensing channel (2a), in the form of a recess in that wall. The filter (A) is inserted into the dispensing channel (2a), positioned within the annular chamber (25) and separating the chamber (25) from the passage (B) available for product flow. The suction openings (23) are positioned in a wall of the annular chamber (25), as shown in Figure 2. The presence of the annular chamber (25) allows the suction effect or negative pressure produced by the suction means to be distributed around the entire filter (A).Therefore, the product is attracted and retained in a circular corona, i.e., on a ring-like surface of the filter (A), which forms an equally annular accumulation that is able to very quickly block the dispensing conduit (2a). To facilitate the restoration of product dispensing after a stop step, i.e., after an activation step of the suction means, the dispensing device is provided with blowing means, placed in communication with the dispensing channel (2a) and arranged to produce a pressure which, in terms of absolute value, is greater than or equal to the negative pressure produced by the suction means in the dispensing channel (2a). In one possible embodiment, one or more blow-off openings (24) are formed through a wall of the dispensing channel (2a). In the solution including the filter (A), the blow-off openings (24) are formed in the filter (A) itself, to direct the airflow through the filter and to promote product detachment. In the embodiment shown, one or more blow-off openings (24) are positioned in the wall of the annular chamber (25). In an alternative embodiment, the airflow produced by the blow-off means could be introduced into the dispensing channel (2a) through the suction opening(s) (23), previously connected to the blow-off means by means of a distribution element, not shown, structured to alternatively connect the blow-off means or the suction means to the suction opening(s) (23). Control of the dispensing device occurs substantially through control of the suction and / or blowing means, if present. In the embodiment comprising only the suction means, activation of these means keeps at least a portion of the product in contact with a wall of the dispensing channel (2a), causing occlusion of the channel. Deactivation of the suction means releases the product, which resumes flow along the dispensing channel (2a). In cases where blowing means are also involved, product dispensing can be controlled in several ways. In one method, material dispensing is initiated by deactivating the suction means and, simultaneously or subsequently, activating the blowing means. In another method, the suction means can remain active at all times, and the blowing means are activated to allow product dispensing. The effect of the blowing means counteracts and cancels the retention effect produced by the suction means. In solutions where the pressure produced by the blowing means is substantially equal, in absolute value, to the negative pressure produced by the suction means, activating the blowing means cancels the negative pressure produced by the suction means, causing the product to be released. In the solution where the pressure produced by the blowing means is greater, in absolute value, than the negative pressure produced by the suction means, the activation of the blowing means introduces an airflow into the dispensing channel (2a). The introduction of this airflow fluidizes the product, causing it to quickly detach from the wall of the dispensing channel (2a) and / or the filter (A). Activating and deactivating the suction and / or blowing mechanisms according to a predetermined time cycle allows for very precise variation of the dispensed product quantity. For example, it is possible to dispense the product in small, successive quantities, defined by the corresponding activation and deactivation cycles of the suction and / or blowing mechanisms. A predetermined number of dispensing devices, according to the present invention, can be arranged along an alignment direction (Z), side by side, to form a dispensing bar of predetermined length. The outlet openings (22) are side by side and oriented in the same direction. For example, the outlet openings (22) are oriented downwards. By creating a flattened outlet opening (22), as shown in the figures, the dispensing devices can be arranged relatively close together, bringing the outlet openings (22) closer to each other. Preferably, the outlet openings (22) are arranged in the same dispensing plane, preferably horizontal. The dispensing bar allows for the definition of a dispensing front of a predetermined length along the alignment direction (Z) of the dispensing devices.For example, in the previously summarized case of depositing on an underlying moving plane, the dispensing bar, arranged in the alignment direction of the transverse dispensing devices, particularly perpendicular to the transport direction of the moving plane, substantially allows the product to be deposited over the entire width of the moving plane, understood as an extension measured perpendicular to the transport direction, without the need to move the dispensing bar transversely to the transport direction. The dispensing channel (2a), the suction opening(s) (23), and the blow-off opening(s) (24) are formed in a body (200). To define the dispensing bar, two or more dispensing devices (2) may be arranged side by side. Two or more dispensing devices (2) may be joined on the lateral surfaces of the respective bodies (200). Figures 6, 7, 8, and 9 illustrate an alternative embodiment of the dispensing nozzle (N), which can be activated by a pneumatic command. The dispensing nozzle (N) comprises a dispensing channel (2a). The dispensing channel has an inlet opening (21) for feeding the product and an outlet opening (22) for dispensing the product. The inlet openings (21) and outlet openings (22) can have different profiles. In the preferred, but not exclusive, embodiment illustrated, the openings (21, 22) have an enlarged quadrangular profile, i.e., they are in the form of slots. This configuration of the inlet and outlet openings (21, 22) allows two or more dispensing devices (2) to be arranged compactly side by side. Preferably, the outlet opening (22) is located at the end of an outlet section (22a) of the dispensing channel (20a) that has an inclined longitudinal axis (X) to allow the granulated material to flow by gravity through the outlet opening (22). For example, the outlet section (22a) is oriented vertically. Similarly, the inlet opening (21) also has a longitudinal axis (X) oriented to facilitate the entry of the granulated material by gravity. For example, the inlet opening (21) is positioned at the end of a vertically oriented inlet section (21a). Furthermore, the inlet section (21a) is hopper-shaped, meaning it has a tapered cross-section from top to bottom. In the embodiment shown, the inlet section (21a) and the outlet section (22a) have an elongated rectangular outline in a cross-sectional plane perpendicular to their respective longitudinal axis (X).The configuration shown in the figures offers the advantage of allowing the side-by-side arrangement of multiple outlet openings (22) and multiple inlet openings (21) in a compact configuration. bren ίη / ΖΖΠΖ / Ε / ΥΙΛΙ The dispensing channel (2a) comprises an intermediate section (23) having a longitudinal axis (Xi). In the embodiment shown, the intermediate portion is concentric with the longitudinal axis (Y) of the intermediate section. Preferably, in a cross-sectional plane perpendicular to the longitudinal axis (Xi), the intermediate section has a rectangular outline. In the embodiment shown, the intermediate section (23), the inlet section (21a), and the outlet section (22a) have the same width, measured in a cross-sectional plane perpendicular to the longitudinal axis (Xi) of the intermediate section. This allows for a homogeneous flow of the granulated material. In a vertical plane containing the longitudinal axis (XI), the intermediate portion has a length (L), measured as the minimum distance between the edges of the inlet (21) and outlet (22) openings, and a height (H), measured perpendicular to the length (L). For example, the height (H) is measured between a joining zone or edge (E) between the inlet opening (21) and the intermediate section (23), and a lower wall (23a) of the intermediate section (23). The intermediate section (23) is configured to allow the deposition and accumulation of a predetermined amount of granular material from the inlet opening (21). In other words, the intermediate section (23) is configured so that the granular material, fed through the inlet opening (21), is deposited and accumulates in the intermediate section (23) and, in the absence of additional stress, does not flow along the intermediate section (23) toward the outlet opening (22). In the preferred but not exclusive embodiment shown, the intermediate section (23) has an inclination, with respect to a horizontal plane, a height (H) and a length (L) such that they stop by force of gravity the flow of material from the inlet opening (21) to the outlet opening (22). The principle for configuring the intermediate section (23) to allow the deposition and accumulation of granular material—that is, to stop the flow of granular material from the inlet opening (21) to the outlet opening (22)—takes into account the internal angle of repose (α) of the granular material. As is well known, granular material, when deposited by gravity on a horizontal plane, forms a conical pile whose basic angle is known precisely as the angle of repose or angle of shear strength. The internal angle of repose (a) is measured with respect to the lower wall (23a) of the intermediate section (23). For example, with the internal angle of repose (a) of the granulated material known, the height (H) times the cotangent of the internal angle of repose (a) is smaller than the length (L) of the intermediate section (23): Hxctg(a) < L Therefore, the granulated material coming from the inlet opening (21) settles and accumulates at the bottom of the intermediate section (23), without being able to reach the outlet opening (22), as shown in figure 3. Therefore, the intermediate section (23) is misaligned with respect to the inlet opening (21) and the outlet opening (22), meaning that the inlet opening (21), the intermediate section (23), and the outlet opening (22) are not concentric with each other. In the embodiment shown, the lower wall (23a) of the intermediate section (23) has a substantially horizontal slope. Therefore, the shape of the intermediate section (23) allows the flow of the granulated material to be stopped, i.e., preventing the dispensing of the same material, without the need for mechanical opening / closing members which, in addition to being costly and problematic to control, can damage the granulated material. To allow the flow of granulated material from the intermediate section (23) to the outlet opening (22), the dispensing device (2) comprises motor means. These motor means can be activated by command to cause the granulated material to flow forward from the intermediate section (23) to the outlet opening (22). Essentially, the action of the motor means advances the granulated material along the intermediate section (23) to the outlet section (22a), through which the granulated material falls by gravity, passing through the outlet opening (22). In one possible embodiment, the motor means comprises a vibrating device arranged to transmit controlled vibrations to the intermediate section (23). The vibrations transmitted to the intermediate section (23) are such that they cause the granulated material to flow towards the outlet opening (22). In the preferred but not exclusive embodiment shown, the motor means comprises pneumatic means (24, 25, 26) provided with a blow-off opening (24) located along the intermediate portion (23). The pneumatic means (24, 25, 26) can be activated by command to send, within the intermediate section (23), an airflow to produce the outflow towards the outlet opening (22) of the granulated material deposited and accumulated in the intermediate section (23). The airflow introduced into the intermediate section (23) through the blowing opening (24) fluidizes and carries the granulated material toward the outlet opening (22), through which the granulated material is dispensed to the outside. In the embodiment shown, once the outlet opening (22) has been reached, the granulated material falls downwards by gravity. Preferably, but not necessarily, the blow-off opening (24) is located on the lower wall (23a) of the intermediate section (23). This positioning of the blow-off opening (24) causes the airflow to also lift the granulated material, effectively facilitating the flow towards the outlet opening (22). Preferably, a filter (25) is associated with the blow-off opening (24). The filter (25) is structured to prevent granulated material from entering the blow-off opening (24). In the embodiment illustrated in Figure 1, the dispensing channel (20), the inlet opening (21), the outlet opening (22), and the blow-off opening (24) are all contained within a single body (20). The pneumatic means (24, 25, 26) comprise a supply device (26), for example, a compressor, connected to the blow-off opening (24). The dispensing device (26) is provided with control means that can be activated by a command to send an airflow to the blow-off opening (24). In one possible embodiment, the dispensing supply source (26) is connected to a storage tank, which in turn is connected to the blow-off opening (24) via a supply conduit. This supply conduit is provided with a solenoid valve, associated with a control module which, according to a defined time cycle, sends a command to open and close the solenoid valve, thereby dispensing the granulated material through the outlet opening (22). Activating / deactivating the motor according to a predetermined time cycle allows for very precise variation of the dispensed product quantity. For example, the product can be dispensed in small, successive quantities, defined by the corresponding cycles of the motor, whether in the form of vibration or blowing means (24, 25, 26). In both solutions, controlling the dispensing of the granulated material does not require mechanical shutoffs, offering the same advantages already mentioned. In this embodiment as well, a predetermined number of dispensing devices, according to the present invention, can be arranged along an alignment direction, side by side, to obtain a dispensing bar of predetermined length. By creating a flattened outlet opening (22), as shown in the figures, the dispensing devices can be arranged relatively close together, bringing the outlet openings (22) closer to one another. Such a dispensing bar allows for the definition of an extended dispensing front along the alignment direction of the dispensing devices.For example, in the previously summarized case of depositing on an underlying moving plane, the printing bar arranged in the alignment direction of the dispensing devices perpendicular to the transport direction of the moving plane allows substantially the product to be deposited over the entire width of the moving plane, understood as an extension measured perpendicular to the transport direction. In the preferred but not exclusive embodiment illustrated in Figures 7 to 10, the dispensing unit (D) comprises an intermediate storage element (10) provided with a plurality of cavities (11) of a predetermined shape and depth or height. Each cavity (11) has an opening that allows the entry of powdered material and subsequent discharge of the previously introduced powdered material. Each cavity (11) is delimited by a side wall and a bottom that may be substantially flat or curved. In a particularly advantageous embodiment, the intermediate element (10) comprises a flexible strip in which cavities (11) are formed, opening onto the surface of the strip. For example, the cavities (11) can be formed by incision or impression on the surface of the flexible strip. In a preferred, but not exclusive, illustrated embodiment, the intermediate element (10) is in the form of a flexible strip closed in a loop. In a preferred but not exclusive embodiment, the cavities (11) comprise a plurality of elongated grooves parallel to one another. These elongated grooves have a closed bottom and are laterally bounded by two walls, which may be parallel or inclined to one another, converging towards the bottom. In one possible embodiment, the elongated grooves have a V-shaped cross-section in a transverse plane. Preferably, the cavities (11) are adjacent to one another. In this first configuration, the cavities (11) can be arranged parallel to the longitudinal (Y) direction of travel, or they can be inclined with respect to the longitudinal (Y) direction in the same plane as the latter. Preferably, but not necessarily, the cavities (11) are all in the form of elongated grooves. Furthermore, the cavities (11) occupy the entire surface of the intermediate element (10). This promotes the filling of the cavities (11). In a second possible modality, not illustrated, the cavities (11) have a prismatic shape, for example, they have a rhomboid outline, but obviously other shapes are possible. The dispensing nozzles (21) located above the intermediate element (10) are arranged to deposit a predetermined amount of powder material into one or more predetermined cavities (11). The distribution unit (D) further comprises a discharge device (30) arranged to move the cavities (11) from a loading position, in which they can receive the powder material from each dispensing device (E), to a discharge position, in which they can discharge the powder material. In a particularly convenient embodiment, the discharge device (30) is structured to move the cavities (11) between a loading position, in which they are oriented upwards to receive the powder material from the dispensing nozzles (21), and a discharge position in which they are oriented at least partially downwards to discharge the powder material essentially by gravity.The movement between the loading position and the unloading position performed by the discharge device (30) occurs by translation along a longitudinal (Y) forward direction, as will be explained further below. In a preferred but not exclusive embodiment in which the intermediate element (10) comprises a flexible band; the discharge device (30) comprises a pair of rollers (31, 32) around which the intermediate element (10) is wound to define a closed-loop passage. The cavities (11) are oriented towards the outside of said closed passage. Along the path defined by the rollers (31, 32), the support element (10) has an upper section (10a) along which it slides forward in the longitudinal direction (Y), and along which the cavities (11) are oriented upwards in the loading position. The dispensing device (E) is located above the intermediate element (10), i.e., above the upper section of the intermediate element (10), so that it can discharge the powdered material downwards into the cavities (11). In other words, during the passage from the loading position to the discharging position, the cavities (11) move from an upward-facing position to a downward-facing position. During this passage, each cavity (11) can discharge its contents downwards.As shown schematically in Figures 7 to 10, the passage of the cavities (11) from the loading position to the unloading position occurs progressively along the section of the intermediate element (10) surrounding the first roller (31). When each cavity (11) is facing downwards, i.e., after having traveled around the first roller (31), the emptying of the contents is substantially complete. Upon rotating around the second roller (32), the cavities (11) will move back to the loading position to receive a new load of powdered material. The cavities (11) are filled during the forward movement of the intermediate element (10) along the longitudinal (Y) direction. Essentially, even as the intermediate element (10) advances, the nozzles (21) selectively and precisely direct the powder material into the cavities (11), according to the desired decorative texture.Not necessarily; it is possible to include a filling device (40) arranged to fill any cavities not filled by the dispensing nozzles (21). The filling device (40) can be used to dispense a specific ceramic material or compound in terms of color and / or grain size or other parameter. Essentially, the filling device (40) discharges the material to fill the hollow or partially empty cavities (11) downstream of the dispensing devices (E), and covers any cavities (11) that may have already been filled. A scraper blade (41) is arranged in contact with the upper section of the intermediate element (10), downstream of the filling device (40), to remove excess powdered material from the depth or height of the cavities (11), and which, therefore, protrudes from the upper surface of the intermediate element (10).The scraper blade (41) is rigidly restricted to the filling device, i.e., it is defined by an edge of the filling device (40). The deposit plane (50) is located below the distribution unit (D). As previously mentioned, there is a relative movement between the distribution unit (D) and the deposit plane (50), directed along the longitudinal direction (Y), which occurs simultaneously with the discharge of the ceramic compound from each dispensing device (E). This allows the ceramic compound to be deposited in a continuous layer (C) onto the deposit plane (50). The relative motion between the depositing plane (50) and the dispensing unit (D) can be achieved, for example, by sliding the depositing plane (50) along the longitudinal (Y) direction, while the dispensing unit (D) remains stationary with respect to the longitudinal (Y) direction. In the embodiment shown, the intermediate element (10), as it slides along its path around the rollers (31, 32), is generally stationary along the (Y) direction. The sliding of the depositing plane (50) can be in the same or opposite direction to the sliding of the upper section of the intermediate element (10) as it moves around the rollers (31, 32). Preferably, but not necessarily, the depositing plane (50) is in the form of a belt or mat that slides along a closed passage defined by two or more rollers, as shown in Figure 1. The relative movement between the deposition plane (50) and the distribution unit (D) involves the deposition of the ceramic material in a continuous layer (C). By regulating the relative speed between the deposition plane (50) and the distribution unit (D), it is possible to adjust the height or thickness of the layer formed on the deposition plane (50). In the embodiment shown, this variation can be obtained by varying the sliding speed of the deposition plane (50) and / or the sliding speed of the intermediate element (10). In one possible embodiment of the machine, the control module is arranged to control each supply device (E) and each nozzle (N) for filling the cavities (11) according to the decoration (V) to be applied to the layer (C). To this end, the control module is equipped with an algorithm that processes an image of the decoration (V) to decompose it into a series of volumes of powder material of a predetermined color, each of which is assigned to a predetermined cavity (11). Thus, the control module regulates the operation of the dispensing device (E) so that each volume is introduced into a predetermined cavity (11).The correspondence between each volume and a respective cavity is established by informing the control module of the position of each cavity (11), the speed of the intermediate element (10), and the speed of the deposition plane (50), for example, by means of an encoder, sensors, or optical systems known in the art. Essentially, starting with the decoration (V) to be carried out, the control module defines the number and position of the material volumes required to achieve it and assigns each volume a cavity (11), relative to the position at which the volume contained in the cavity (11) will be discharged onto the deposition plane (50). To improve the deposition of the material onto the deposition plane (50) and preserve the decoration distributed in the cavities (11) by means of the dispensing device (E), it is preferable to minimize the distance between the upper section of the intermediate element (10) and the deposition plane (50). For example, the distance between the upper section of the intermediate element (10) and the deposition plane (50) can be reduced by using a first roller (31) with a reduced diameter. In the modality shown, in which the distribution unit (D) comprises the intermediate element (10), the container (F) is located near the first roller (31), i.e., near the area where the discharge of the cavities (11) occurs. A first wall (33a) is located near the first roller (31), i.e., near the area where the cavities (11) discharge occurs. The first wall (33a) is arranged and configured to intercept the material discharged from the cavities (11), guiding or altering its trajectory within the collection space (33c). The second wall (33b) is located upstream of the first wall (33a) with respect to the direction of travel of the cavities (11). The second wall (33b) is positioned not to interfere with the material projected forward by the cavities (11), but rather to contain the material intercepted by the first wall (33a) as it falls downward. To this end, the second wall (33b) has an upper edge positioned at a lower height relative to the path followed by the material discharged from the cavities (11).For example, the upper edge of the second wall (33b) is located below the horizontal diametric plane of the first roller (31).
Claims
1. A machine for the dry decoration of slabs or tiles, comprising: a depositing plane (50); a distribution unit (D) arranged to dispense, in a controlled manner, a ceramic compound in granular or powder form; a storage container (F) interposed between the distribution unit (D) and the depositing plane (50) for storing a certain quantity of ceramic compound dispensed by the distribution unit (D), and comprising a discharge opening (O) arranged to allow the deposit of the ceramic compound onto the depositing plane (50); wherein the storage container (F) and the depositing plane (50) are in relative motion with respect to each other along a longitudinal direction (Y); a control module, connected to the distribution unit (D) and arranged to control and regulate the supply of the ceramic compound by the distribution unit (D);one or more sensors (S) connected to the control module and arranged to detect a significant parameter of the quantity of ceramic compound contained in the storage container (F) and to process a corresponding measurement signal; wherein the control module is arranged to regulate the supply of the ceramic compound as a function of the received measurement signal, to maintain a desired quantity of the ceramic compound within the container (F); characterized in that: the dispensing unit (D) comprises a dispensing device (E) equipped with a plurality of dispensing nozzles (N), each of which is provided with a shut-off device, which can be activated between a flow configuration, in which the supply of a ceramic material is determined, and a stop configuration; each shut-off device is controlled by the control module independently of the other shut-off devices;The distribution unit (D) comprises an intermediate storage element (10) provided with a plurality of cavities (11), located above the storage plane (50) and below the dispensing device (20); each cavity (11) has an opening that allows the entry of powdered material and subsequent discharge of the previously introduced powdered material; The distribution unit (D) comprises a discharge device (30) arranged to move the cavities (11) from a resting position, in which they can receive the powdered material from each dispensing device (E), to a discharge position, in which they can discharge the powdered material downwards.
2. The machine according to claim 1, further characterized in that the intermediate element (10) comprises a flexible belt; the discharge device (30) comprises a pair of rollers (31, 32) around which the intermediate element (10) is wound to define a closed-loop passage; the cavities (11) are oriented towards the outside of said closed passage.
3. The machine according to claim 1 or 2, further characterized in that the control module is arranged to regulate an activation time cycle in the flow, and stopping configurations for each shutter device.
4. The machine according to any of the preceding claims, further characterized in that the shut-off devices can be activated between flow and stop configurations by a pneumatic command, and wherein the control module is arranged to regulate the pneumatic command for each shut-off device.
5. The machine according to any of the preceding claims, further characterized in that at least one sensor (S) is arranged to measure a level reached by the ceramic compound within the storage container (F).
6. The machine according to claim 1, further characterized in that at least one sensor (S) is arranged to measure the weight of at least a portion of the ceramic compound within the storage container (F).
7. The machine according to any of the preceding claims, further characterized in that each dispensing nozzle (N) comprises: a dispensing channel (2a), provided with a longitudinal axis (X), an inlet opening (21) and an outlet opening (22); wherein the obstructing devices comprise suction means, arranged to retain, by command, at least a portion of granular or powdered material within the dispensing channel (2a), to form an accumulation that obstructs the dispensing channel (2a) and prevents the flow of material.
8. The machine according to claim 7, further characterized in that each dispensing nozzle (N) comprises one or more suction openings (23), formed through a wall of the dispensing channel (2a) and placed in communication with the suction means.
9. The machine according to claim 8, further characterized in that each dispensing nozzle (N) comprises a filter (A) interposed between each suction opening (23) and the dispensing channel (2a).
10. The machine according to any of the preceding claims, further characterized in that each dispensing nozzle (N) comprises a dispensing channel (20) provided with an inlet opening (21) and an outlet opening (22), wherein: the dispensing channel (20) comprises an intermediate portion (23), which connects the inlet opening (21) and outlet opening (22) and is provided with a longitudinal axis (Y); the intermediate portion (23) has a length (L) and a height (H), measured in a vertical plane containing the longitudinal axis (Y), wherein the height (H) is measured perpendicular to the length (L); the intermediate portion (23) is configured to enable the deposition and accumulation of a predetermined quantity of granulated material coming from the inlet opening (21);wherein the shut-off devices comprise a motor means that can be activated by command to cause the granulated material to flow forward from the intermediate portion (23) towards the outlet opening (22).; 11. The machine according to claim 10, further characterized in that the motor means comprises a pneumatic means (24, 25, 26), provided with a blowing opening (24) located along the intermediate portion (23).
12. The machine according to claim 11, further characterized in that the pneumatic means (24, 25, 26) comprises a dispensing device (26) connected to the blow-off opening (24), which is provided with a control means that can be activated on command to send an air flow to the blow-off opening (24).
13. The machine according to any of claims 7 to 12, further characterized in that it comprises two or more dispensing nozzles (N) according to at least one of the preceding claims, arranged side by side along an alignment direction (Z), with the outlet openings (22) side by side and oriented in the same direction to define a deposit front of predetermined length.