ES2530220T3 - System for loading presses for ceramic products - Google Patents

Abstract

System for loading and depositing layers of powders in a press (11) for ceramic products, comprising a first device (13) for discharging powders and a second device (14) for discharging powders, which receives from the first, said first device being ( 13) external with respect to the press and said second device (14) sliding horizontally to be moved between a loading position below the first device (13) and a path for unloading in the press (11), presenting the first and second discharge devices each one a discharge mouth (21) that is fed through an opening (22), characterized in that said opening (22) of each discharge device is provided with a "guillotine" type interception shutter ( 23), which is controlled to slide in a substantially vertical plane containing the opening (22).

Description

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DESCRIPTION

System for loading presses for ceramic products.

The present invention relates to a system for loading mixtures (raw material) in presses for pressing ceramic products, such as tiles, made from ceramic material with two or more layers.

The systems for loading presses for ceramic products generally comprise a truck that slides horizontally in and out of the press, which is loaded with ceramic powder by a suitable feeder. In order to make thin surface layers, said truck comprises a small unloading device that is operated while the carriage slides through the pressing cell, said cell being already generally filled with the main powder layer by means of a loading rack, also fixedly connected to the truck. Normally, the unloading device, in turn, is charged by an additional unloading device, stationary on the outside of the press, thus carrying out a two-phase unloading system. EP-A-1 358 983 shows a system according to the preamble of claim 1.

Two-phase systems are found, for example, with discharge devices provided with shutters that rotate about a horizontal axis showing a discharge opening facing downwards. A problem is the discharge in a sufficiently uniform manner. In addition, known systems do not allow the layer to be measured in a sufficiently controlled manner, especially at the beginning and end of the deposit and, often, local thickens are formed on the surface of the tile that, consequently, affect the quality of the product negatively.

In addition, in the known systems, the lack of precision at the beginning and at the end of the discharge causes the dispersion of the powders outside the cell. Together with said dispersion, the dispersion of powders in the environment also takes place due to the type and discharge from one phase to the next. All of the above leads to a variety of problems, for example, in the case of mixtures that are particularly valuable and / or that should not be dispersed in the environment, due to cost and / or environmental pollution problems. Dust dispersion also leads to product quality problems. In addition, dispersed powders may contaminate other mixtures that may be present (for example, the mixture to be used to create the bottom layer and which will form the actual body of the tile).

WO-A-02/07939 discloses dust distribution devices in which the distribution opening is provided with a gate valve.

The general objective of the present invention is to avoid the aforementioned disadvantages by providing a charging system that allows a low dispersion of the powders to be obtained, which prevents accidental spillage, has a precise discharge and deposits homogeneous and constant layers. , even those of low thickness.

In view of said objective, it is intended to carry out, according to the invention, a system for loading and depositing layers of powders in a press for ceramic products according to claim 1.

In order to clarify the explanation of the innovative principles of the present invention together with its advantages over the prior art, a possible embodiment using these principles will be described below with the help of the attached drawings.

In the drawings:

Figure 1 represents a schematic and sectional side view of the upper part of a system for loading a press according to the invention;

Figure 2 represents a schematic sectional view of a detail of the system of Figure 1;

FIG. 3 represents a partial schematic perspective view of a system according to the invention with a plurality of loading devices.

Referring to the figures, Figure 1 schematically shows a system, generally indicated by reference number 10, for loading and depositing layers of powders in a press 11 for tiles and similar ceramic products. In particular, the system is suitable for depositing thin layers, for example, for applying dry enamel.

The system comprises at least one distribution module 12 formed by a first device 13 for the discharge of dusts into a second device 14 for discharging dusts.

The first device 13 is external with respect to the press, while the second device 14 can be

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slide moving horizontally between a loading position under the first device and a path for unloading in a press cell 30 in the press. The device 14 is slightly raised with respect to the slide plane of the powders and has exactly the same length (transverse to the movement of entry to the press) as the cell to be loaded. Advantageously, the first device 13 moves vertically, by means of the actuators 15, to place its discharge mouth against the dust receiving container of the second device in a loading position.

The first device 13, in turn, is supplied with powders thanks to feeding means 17 that discharge the powders into the container of the first device. Advantageously, said feeding means use a sliding feeding tube 17 that enters the dust container of the first device to insert the powders therein and that slides along the container to deposit the dust for its entire length.

Such means are substantially of the known type and can be easily imagined by one skilled in the art. Therefore, they will not be shown or described further.

The horizontal movement of the second device is achieved by means of a motorized trolley structure of the appropriate mode 18. Advantageously, said structure, as well as the movement of the device 14 back and forth, also supports and moves a loading rack 19 that is supplied with powders using a hopper 20 to load the mixing base into the mold.

The sliding of the grid is controlled between the external position with respect to the press and a position for unloading in the press cell, passing under the hopper to fill the grid. Advantageously, the second device 14, which, in practice, moves in solidarity with the loading grid, is arranged on the front of the grid in the direction of entry into the press.

The two discharge devices are substantially similar, apart from their sizes. In fact, the upper one has the function of being a dust deposit and tends to have a greater capacity, while the lower one, which presents the function of being a distributor of the material in the mold cavity, has a lower capacity, so It has a smaller size and can easily enter the press. The dispensing device 14 is supplied when necessary by means of the storage device 13, in general, when the truck is idle. For example, a known probe can be provided to record the amount of mixture present in the distributor and to control the filling.

Figure 2 shows the structure of one of the two powder discharge devices in greater detail (substantially, the other varies only in the size of the powder container).

Each of the discharge devices has a discharge mouth 21 (advantageously open in a horizontal plane) that is fed by an opening 22 open in a substantially vertical plane, as wide as the mold and provided with an interception shutter of the " guillotine ”23 which is controlled to slide by means of a suitable actuator 24 in the vertical plane containing the opening 22.

The tube 25 upstream of the opening 22 has a lower plane inclined downward between the container 26, which receives the powders, and the opening 22. The inclination is sufficient to ensure efficient sliding of the powders.

On the other hand, the tube 27 downstream of the opening is vertical towards the respective supply port, is as wide as the mold and the plug slides therein.

As can be clearly seen in Figure 2, the shutter, advantageously, has a lower edge that forms an acute angle 28 against the vertical sliding surface 29. This allows the mixture to be "cut" to be dispersed during closing. , without causing the crushing of dust particles, which would lead to the formation of scales. When the plug is in its closed position (shown in Figure 2) its end portion is smaller than a small portion with respect to the inclined tube 25, so as to ensure that the plug is perfectly sealed.

The tubes 25 and 27 and the sliding seat of the shutter, advantageously, can be obtained in a single metal block mechanized suitably by machining by chip removal. This ensures that the structure, to which the dust container is applied, is simple and robust.

Thanks to the use of vertical shutters and the structure mentioned above, it has been shown that it is easy to create a fine and controlled dispersion of a mixture (in a granulated state) for the entire length of the cell. The density of the dispersed mixture (or, better, the amount of deposited material) is not adversely affected by the amount of mixture present in the distributor.

In addition, no flakes are formed in the mixture, which could partially obstruct the system itself or, in any case, give the final product a poor quality appearance.

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There has also been a minimization of the appearance of dust clouds, which when deposited could contaminate other possible mixtures, thus creating aesthetic problems, in addition to technical problems, during the following manufacturing phases and, in any case, they constitute a waste and, therefore, an economic loss, due to the high costs of the mixtures, in addition to being potentially harmful.

Thanks to the system described, high quality tiles can be obtained, saving on the use of valuable raw materials and reducing the dispersion of fine powders in the environment. In addition, the system is easily applied and has great flexibility, therefore, for example, it is suitable for the manufacture of small items that have the same format, but with different color or tone.

It should be noted that the creation of the dispersed mixture, in the case where it is desired to deposit thin layers, allows the material to be deposited directly on the mold cavity, or better, it is not necessary for the mold to make an intermediate fall, in order to create a compartment in which the new mixing layer is received (as is known, this movement of the mold can cause the already deposited powders to be re-mixed, which is not aesthetically appropriate in the final product).

In order to minimize dust diffusion defects on the edges at the beginning and end of the mold, the opening and closing of the shutters is easily controlled, so that they take place exactly at the beginning and at the end of The cell itself.

The movement of the shutter of the upper device 13 can simply be of the opening and closing type, while for the shutter of the lower device 14, the movement can be advantageously of the continuous type, with the option of partialising the opening, so that it can be precisely regulate the amount of dusts in the outlet. Otherwise, the amount deposited can be regulated exclusively by the speed of passage of the truck on the cell.

All of the above can be achieved by means of a suitable and already known electronic control system of the movement of the truck and the shutters, which can be easily imagined by one skilled in the art and, therefore, will not be shown or described in detail. Advantageously, the movement of the truck can be achieved with stepper motors (or an equivalent system).

In Fig. 3, a possible system structure according to the invention is partially schematically visible, comprising a plurality of pairs of distributor modules, each consisting of the first and second discharge devices 13 and 14 mentioned above. . In particular, as many rows of modules as cells are provided in said structure (ie, the "outputs" of the mold). A grid (not shown in Figure 3) can also be provided for each cell.

In the case where the mold is replaced by another that has a different number of outputs, the module set can easily be replaced by a new one, suitable for the new mold (new cell format and / or number of cells).

Again, as shown in Figure 3, many modules can also be mounted in series, one after the other, so that many layers of mixture can be loaded or, when the mold has many aligned cavities, get tiles that have different colors or tones in the different outputs of the mold or even use a different module for the different cells of the mold, for example with two outputs, loading the first output using the first respective module and the second output with the second module respective (or vice versa), said selection varying (even from pressing cycle to pressing cycle) acting on the machine.

Because, in some cases, it is necessary that the minimum distance between the last module and the grid behind it is at least equal to the length of the cell (for example, when it is necessary for the module to make an intermediate fall , to receive a thick layer of mixture), the grid itself can be equipped with a known movement device capable of bringing it closer to the later module, in the event that the need mentioned above no longer exists, thus obtaining a shortening of the travel path. the truck and the production cycle.

This solution may also be convenient when there are many modules in series and it has been decided to eliminate some. Then, the space that is now empty can be used.

At this point, it is clear that the objectives have been achieved, providing a charging system that is simple, flexible and efficient.

Obviously, the above description of an embodiment that applies the innovative principles of the present invention is provided by way of example of said innovative principles and, therefore, should not be considered as limiting the scope of protection claimed herein. memory.

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Claims (9)

1. System for loading and depositing layers of powders in a press (11) for ceramic products, comprising a first device (13) for discharging dusts and a second device (14) for discharging dusts, which receives from the first 5, said being first external device (13) with respect to the press and said second device (14) sliding horizontally to be moved between a loading position under the first device (13) and a path for unloading in the press (11), presenting the first and second discharge devices each a discharge mouth (21) that is fed through an opening (22), characterized in that said opening (22) of each discharge device is provided with an interception shutter of the " guillotine ”(23), which is 10 controlled to slide in a substantially vertical plane containing the opening (22). System according to claim 1, characterized in that the first device (13) can be moved vertically to place its discharge mouth against a dust receiving container (26) of the second device (14) in the loading position. fifteen

3.

System according to claim 1, characterized in that feeding means (17) are provided that discharge the powders into the first device (13).

Four.

System according to claim 3, characterized in that the feeding means use a tube of

20 sliding feed (17) that enters the dust container (26) of the first device for transporting the powders into it. System according to claim 1, characterized in that a tube (25) upstream of the opening (22) has a inclined lower plane and a tube (27) downstream is vertical towards the respective discharge mouth (21). 25 System according to claim 1, characterized in that the shutter has a lower edge that forms an acute angle (28) against the sliding surface (29). System according to claim 1, characterized in that it comprises means (18) for loading a mixture of base into the mold. System according to claim 7, characterized in that the loading means (18) comprise a loading grid (19) controlled to slide between an external position with respect to the press and a position for unloading in a cavity (30) in the press (11) on the path that passes under a hopper (20) to fill the 35 grid System according to claim 8, characterized in that the second device (14) moves in solidarity with the loading grid (19) and is arranged in front of the grid in the direction of the press entrance. A system according to claim 1, characterized in that it comprises a plurality of pairs of said first and second discharge devices (13, 14), for depositing a plurality of layers of powders into one or more cavities (30). 5