IT202300009579A1 - Apparatus and process for the creation of veining in slabs and plant for the production of slabs with a veined effect - Google Patents

Description

Description of the industrial invention entitled "Apparatus and process for the creation of veining in slabs and plant for the production of slabs with a veined effect"

The present invention relates to the technical sector of the production of slabs made of conglomerate of stone material and/or ceramic material and/or sintered stone starting from at least one mixture.

In particular, the present invention relates to an apparatus and a process for creating veins in slabs produced from at least one basic mix and at least one complementary mix.

In particular, the veins in the slabs are obtained starting from the complementary mix distributed inside appropriate grooves made in the base mix layer.

Generally, the complementary dough has at least one external appearance and color different from the basic dough.

The basic mix and the complementary mix are intended to subsequently undergo at least one compaction phase, carried out for example by means of a press that uses vacuum vibro-compression, and a hardening phase to obtain the slabs with the veins, carried out for example by means of a catalysis oven.

The present invention also relates to a plant for the production of slabs, in particular slabs with a veined effect, and comprising the aforementioned apparatus. The production of slabs in conglomerate of stone material and/or ceramic material and/or sintered stone starting from a base mix has been known for some time; such production preferably involves the use of Bretonstone<?> technology.

The apparatus and machines used to produce slabs generally include a distributor for distributing a mixture onto one or more temporary supports, such as moulds or trays made of elastomeric material.

The basic mix mainly comprises a granulated stone and/or lithoid and/or ceramic and/or sintered stone powder material and a binder, for example an inorganic binder or a hardenable resin.

The dough distributor can be of the weight type and therefore consist of a hopper suitable for containing a predetermined quantity of basic dough to be distributed in the temporary supports and an extractor belt suitable for receiving the basic dough from the hopper and distributing it on the temporary supports in relative motion with respect to the weight distributor.

Such apparatus may also comprise one or more dispensers of a colorant on the base mixture in order to create slabs with inclusions of colorant, in particular having a veined effect.

In particular, the colorant dispensers are positioned above the extraction belt to distribute one or more colorants, liquid or powder, on the base mixture before the latter is distributed into the temporary supports.

The devices described above, although widely known and appreciated in the sector, are not free from some drawbacks.

A first drawback is represented by the fact that the distribution of the colorant on the mixture occurs randomly. This drawback therefore prevents the creation of slabs with inclusions, in particular long veins, with a predefined profile or design.

Another drawback is that the devices described above do not allow for the creation of veins in the slabs with variable lengths or for the creation of a veined stain effect, that is, with pre-established areas having different chromatic tones or shades compared to the body of the slab.

To overcome these drawbacks, the apparatus described above may comprise one or more processing heads, each comprising a dough processing tool and a device for dispensing liquid or powdered colouring.

In particular, the working tool can consist of a ploughshare or a furrower and is intended to create furrows in the thickness of the base mix previously distributed on the temporary support.

Subsequently, the dispensing device distributes the dye inside the grooves previously created by the working tool in order to create the inclusions, in particular the veins.

An example of such apparatus is described in international patent application no. WO2016/113652; the apparatus described therein includes, in addition to the ploughshare, a whisk for mixing the base mixture and the colorant in the areas where the liquid or powdered colorant has previously been dispensed.

A first drawback of these latter solutions is represented by the fact that they do not allow the creation of inclusions, in particular veins, with particularly significant widths, for example close to a few dozen centimetres, and at the same time having a marked colour compared to the mixture.

Another drawback is that the width of the achievable grain can only vary within a limited range of values.

To further overcome these last drawbacks, further apparatus and machines have been developed in which the dye distributed in the furrows is formed by a mixture similar to the basic mixture but having a different colour and appearance from the basic mixture; this mixture is also defined as complementary mixture or colouring mixture or veining mixture.

An example of such apparatus is described in international patent application No. WO2020/115644. The apparatus described in this patent application comprises at least one tool for working the basic mixture to form the grooves and at least one dispensing device for distributing the complementary mixture inside the grooves, the complementary mixture being suitable for forming the veins in the finished slabs.

The at least one processing tool and the at least one dispensing device are placed on processing heads which are in turn mounted on robotic anthropomorphic arms.

As in WO2016/113652, also in WO2020/115644 the furrowing tool can be adapted to be moved alternately along a transverse direction with respect to the direction of advancement of the temporary support with the basic mix in order to create furrows with increased width, or it can consist of a ploughshare adapted to be moved by oscillation around a vertical axis to create wider furrows.

Alternatively, the working tool may consist of a mushroom-shaped furrower, i.e. a tool with a cylindrical or preferably inverted truncated-conical shank equipped with a disk on top. The function of the mushroom-shaped furrowing tool is to prevent the base mix removed from the furrow from splashing outwards and to compress the base mix at the edges of the furrows.

A drawback of this last solution is that the overall times for the production of the plates are particularly long.

A further drawback of this last solution, especially when using a ploughshare as a furrowing tool, is that it is only possible to increase the width/amplitude of the grain and the definition/sharpness of the grain contours to a limited extent.

In fact, to increase the width of the veins, the ploughman must move a considerable quantity of mixture along the sides of the furrows; this operation is particularly complex, in particular because the mixture tends to compact excessively along the sides of the furrows.

Furthermore, during the subsequent compaction phase, the mix should undergo a further movement in proximity to the sides of the grooves; this movement of the base mix is particularly complex, generating stresses on the press used to carry out the subsequent compaction phase by means of vibro-compression, and creates evident structural and aesthetic defects in the finished slabs.

In fact, the maximum width of the veins that can be obtained using these technical solutions is between 6 cm and 7 cm.

In accordance with further technical solutions, the veins can also be obtained by using at least one template comprising one or more grooves corresponding to the veins to be created.

For example, from Italian patent application no. 102021000023540, a process is known that includes the following phases:

- positioning of a grooved template inside the mold or tray and distribution of the complementary mixture in the grooves to create veining lines;

- pressing of the grain cords using a pressing cover;

- removal of the jig and pressing cover from the mould;

- covering the grain lines using a covering element with inverted "U" profiles and filling the empty areas of the mould with the basic mixture.

Subsequently, after removing the covering element, the mixtures undergo the compaction and hardening phases described previously.

This last technical solution is however characterised by limited flexibility and high costs, as each grain configuration to be created in the slabs requires a specific template, as well as a specific pressing cover and covering element.

These drawbacks also lead to an increase in overall processing times, since the operations of replacing the templates, pressing covers and covering elements necessarily require the stopping of the apparatus used to carry out the process.

The main purpose of the present invention is therefore to provide an apparatus and a process for the creation of veins in slabs produced starting from at least one basic mix and at least one complementary mix and a plant for the production of such slabs which allow the above-mentioned drawbacks to be resolved.

A particular aim of the present invention is to provide an apparatus and a process of the type described above which allow veins of different widths to be produced flexibly and rapidly.

A further aim of the present invention is to provide an apparatus and a process of the type described above which allow the creation of particularly large and broad veins in the slabs, having widths equal to or greater than 30 cm.

Another aim of the present invention is to provide an apparatus and a process of the type described above which allow for a reduction in the processing times required to create the veining in the slabs.

A further aim of the present invention is to provide an apparatus and a process of the type described above which allow the creation of veins having clear and well-defined contours with respect to the body of the slab.

Another aim of the present invention is to provide a plant of the type described above which allows for a reduction in the time and overall costs of producing slabs having veins with increased and variable width.

The purpose and main tasks described above are achieved with an apparatus and a process for the creation of veining in slabs produced from at least one basic mix and at least one complementary mix in accordance with claim 1 and claim 25 respectively and by a plant for the production of such slabs with a veined effect in accordance with claim 24.

In order to clarify the explanation of the innovative principles of the present invention and its advantages over the known art, some exemplary embodiments of the apparatus which is the object of the present invention will be described below, with the help of the attached figures. In particular, in the figures:

- Figures 1-7 are schematic front views and their enlargements illustrating the veining apparatus as a whole and the stations that compose it in accordance with a first embodiment;

- Figures 8-14 are schematic front views and their enlargements illustrating the veining apparatus as a whole and the stations that compose it in accordance with a second embodiment;

- Figures 15-23 are schematic front views and their enlargements illustrating the veining apparatus as a whole and its component parts in accordance with a third embodiment;

- Figures 24-30 are schematic front views and their enlargements illustrating the veining apparatus as a whole and its component parts in accordance with a fourth embodiment.

The present description, provided for illustrative purposes only and not to limit the scope of protection of the invention, mainly refers to an apparatus and a process for the creation of veins in slabs produced starting from at least one basic mixture M1 and at least one complementary mixture M2.

In particular, the veining in the slabs is obtained from:

- accumulations C of complementary mix M2 distributed in grooves S formed in a layer of basic mix M1 and intended to create veining cords in the basic mix M1; and possibly

- a colorant D, preferably liquid but possibly also in powder form, sprayed or distributed on the sides of the furrows S before distributing the complementary mixture M2 inside them.

The basic mix M1 and the complementary mix M2 are intended to subsequently undergo at least one compaction phase for the production of the slabs. The slabs are made of a conglomerate of stone material and/or ceramic material and/or sintered stone starting from the basic mix M1 and the complementary mix M2, these mixes comprising granules and/or fragments and/or powders of stone material and/or ceramic material and/or sintered stone and a hardenable binder.

In this regard, the M1, M2 mixes are also intended to undergo a binder hardening phase carried out downstream of the compaction phase, as further described below with reference to the slab production plant.

Furthermore, the complementary M2 mix differs from the basic M1 mix mainly in terms of colour and external appearance; these characteristics define the shade and external appearance of the veining present in the finished slabs.

However, the basic dough M1 and the complementary dough M2 may also differ from each other in terms of composition or chemical-physical characteristics, without thereby departing from the scope of protection of the present invention.

The apparatus of the type described above is generally indicated by the reference number 1 in the attached figures. Furthermore, the apparatus 1 can preferably be arranged in a plant for the production of slabs with a veined effect, also an object of the present invention and not illustrated in the attached figures.

As is known, the plant comprises in succession, downstream of the apparatus 1 for the creation of the veining, a station for the compaction of the basic mixture M1 and the complementary mixture M2 previously distributed on at least one temporary support S, a station for the hardening of the mixtures M1, M2 and a transport line of the at least one temporary support S containing the mixtures M1, M2 between the apparatus 1 and the compaction and hardening stations located downstream.

Preferably, the compaction of the M1, M2 mixtures carried out in the corresponding station occurs by means of vibro-compression under vacuum. Instead, the station for hardening the mixture binder may include a catalysis oven if the binder is made up of a resin. Furthermore, the transport line may include one or more conveyor belts.

Downstream of the hardening station, the system can also include a station for processing the surfaces of the slabs, for example by calibrating and/or smoothing and/or polishing.

The compaction station, the hardening station, the processing station and the temporary supports transport line S are of a known type and are not illustrated in the attached figures.

In a preferred form of the invention, the apparatus 1 comprises in succession:

- first means 2 for distributing at least one layer of base mix M1 on a supporting surface 4;

- means 6 for forming grooves G in the at least one layer of base mixture M1 distributed on the supporting surface 4;

- second means 8 for the distribution of the complementary mixture M2, intended to create the veins in the slabs, in the grooves G.

The support surface 4 is placed in relative movement with respect to the first distribution means 2, to the forming means 6 of the grooves G and to the second distribution means 8.

Advantageously, the first means 2 for distributing the basic mixture M1 comprise at least one hopper 10 suitable for receiving the basic mixture M1 from a respective supply line 12 and a first inclined extraction belt 14 positioned downstream and in a position below the hopper 10. The inclined extraction belt 14 and the hopper 12 form a weight distributor, of a type known in the sector.

Furthermore, as illustrated in figures 1, 4, 8, 11, 15, 18, 24 and 27, the first means 2 for distributing the basic mixture M1 comprise at least one crushing device 16 with counter-rotating rollers 17 and a substantially horizontal conveyor belt 18 positioned below the crushing device 16.

The conveyor belt 18 and the crushing device 16 are interposed between the feed line 12 and the hopper 10.

The counter-rotating rollers 17 have the function of shredding the base dough M1 coming from the feed line 12, the shredded base dough M1 being subsequently distributed on the conveyor belt 18 and from there transferred into the hopper 10.

At the end of the conveyor belt 18, the first distribution means 2 may also comprise a disintegrating roller 20, of the type illustrated in figures 1, 4, 8 and 11; the disintegrating roller 20 acts on the base mix M1 before feeding the hopper 10 and is designed to disintegrate and crush the base mix M1, eliminating any clods.

Such a disintegrating roller 20 is of the type described for example in Italian patent no.

1393456.

The first means 2 for distributing the basic mixture M1 may also comprise different or additional components with respect to the components described above, without thereby departing from the scope of protection of the present invention.

Advantageously, the second means 8 for distributing the complementary mixture M2 can comprise a dispenser consisting of a container 22 with an opening 24 for the exit of the complementary mixture M2, as better visible in figures 7, 14, 21 and 28.

The container 22 can be equipped with rotating blades, not visible in the attached figures, with a respective motorization to facilitate the exit and distribution of the complementary mixture M2 from the bottom opening 24.

Furthermore, downstream of the means 6 for forming the grooves G and upstream of the second means 8 for distributing the complementary mixture M2, the apparatus 1 may also comprise means 26 for dispensing a colourant D, preferably liquid but possibly also in powder form, onto the sides of the grooves G.

The dispensing means 26 are better visible in figures 6, 13 and 20 and may comprise at least a pair of spray nozzles 27 if the colorant D is liquid.

It is therefore observed that the third embodiment and the fourth embodiment differ from each other at least in that the fourth embodiment does not include the means 26 for dispensing the colorant D.

The D colorant has a different coloration compared to the coloration of the complementary M2 mixture with which the veins are created and allows the veins to be made clearer, further enhancing their aesthetic effect in the slabs and reproducing the veining present in natural materials in an almost faithful way.

In accordance with the first embodiment and the second embodiment of the apparatus 1 illustrated in figures 1-7 and 8-14 respectively, the support surface 4 for the distribution of the at least one layer of base dough M1 is constituted by the bottom wall of a temporary support S, i.e. a tray or a mould.

It is further observed that in such embodiments, the means 6 for forming the grooves G, the means 26 for dispensing the colourant D and the second means 8 for distributing the complementary mixture M2 are respectively placed in independent stations 6A, 26A and 8A of a series and arranged in succession.

The temporary support S containing the basic mix M1 is transferred from the first distribution vehicles 2 to the further stations 6A, 26A, 8A of the apparatus 1 and to the mix compaction and hardening stations M1, M2 of the slab production plant.

In particular, the transfer of the temporary support S is preferably carried out by means of suitable advancement means, for example conveyor belts of the type illustrated in figures 1-7 and 8-14, which may be mobile conveyor belts 28 or fixed conveyor belts 29.

In particular, the conveyor belt 28 designed to support the temporary support S during the distribution of the at least one layer of base mixture M1 by the first distribution means 2 is mobile while each of the stations 6A, 26A, 8A comprises advancement means consisting of respective fixed conveyor belts 29. The aforementioned embodiments also provide that the means 6 for forming the grooves G and the second means 8 for distributing the complementary mixture M2, as well as the means 26 for dispensing the colorant D, are mounted on Cartesian type movement means 30 (see figures 1-7) or anthropomorphic type movement means 34 (see figures 8-14).

The Cartesian type handling means 30 preferably comprise respective carriages 31 suitable for supporting the various forming, dispensing and distribution means; each of the carriages 31 is mounted slidably on a longitudinal beam 32 supported by a pair of lateral shoulders 33, so as to be movable above the fixed conveyor belts 29.

The anthropomorphic handling means 34 preferably comprise respective robotic arms 35 on which the various forming, dispensing and distribution means described above are mounted.

Alternatively, in accordance with the third embodiment and the fourth embodiment of the apparatus 1 illustrated respectively in figures 15-23 and 24-30, the support surface 4 for the distribution of the at least one layer of base dough M1 is constituted by the upper surface of a conveyor/extractor belt, possibly covered with a protective film.

In particular, the support surface 4 is formed by the upper surface of the first inclined extractor belt 14 of the first distribution means 2. The first inclined extractor belt 14 of the third and fourth embodiments coincides with the first inclined extractor belt 14 of the first and second embodiments.

In the third embodiment and in the fourth embodiment, at least the forming of the grooves G and their filling with the complementary mixture M2 are carried out on the base mixture layer M1 distributed on the first extraction belt 14. These last two embodiments differ from each other, in addition to the lack of the means 26 for dispensing the dye D in the fourth embodiment as described above, also in the fact that the fourth embodiment comprises means 6 for forming the grooves G with a different configuration compared to the forming means 6 of the third embodiment (as described in detail below).

In these embodiments, the means 6 for forming the grooves G and the second means 8 for distributing the complementary mixture M2, as well as the means 26 for dispensing the colourant D where provided, are positioned in succession in correspondence with the first inclined extraction belt 14, as visible in figures 15 and 24.

It should also be noted that, in these latter embodiments, the means 6 for forming the grooves G and the second means 8 for distributing the complementary mixture M2, as well as the means 26 for dispensing the colourant D where provided, are mounted on respective anthropomorphic type movement means 36, of the type described above with reference to the second embodiment, and comprising respective anthropomorphic arms 37, or on Cartesian type movement means.

As illustrated in Figures 15-23 and 24-30, the third and fourth embodiments of the apparatus 1 further comprise:

- a second inclined extractor belt 38 located downstream from the first inclined extractor belt 14, and therefore downstream from the forming means 6, the dispensing means 26 where provided and the second distribution means 8;

- means of rolling 40 of at least one layer of base mix M1 with the complementary mix M2 to form the grain lines.

The second inclined extractor belt 38 is intended to deposit the at least one layer of base mix M1 with the complementary mix M2 which forms the veins in a temporary support S. This last temporary support S is intended to be transferred to the next compaction station of the plant by means of a mobile conveyor belt 28 of the type described above.

The rolling means 40 are located between the first inclined extractor belt 14 and the second inclined extractor belt 38 and may be of the type described in international patent application No. WO2020/058835.

In particular, the rolling means 40 may comprise at least a pair of rollers 41 with rotation axes staggered along the longitudinal direction and/or along the vertical direction, as better visible in figures 20-23 and 29-30.

In accordance with a peculiar aspect of the invention, the means 6 for forming the grooves G in the at least one layer of base dough M1 comprise at least one device 42 for suctioning the base dough M1 in quantities and with paths corresponding to the grooves G to be formed in the layer of base dough M1.

In the context of this description, the arrangements and configurations described above with reference to the forming means 6 are therefore to be understood as referring at least to the suction device 42.

For example:

- with reference to the first and second embodiments, the at least one device 42 for suction of the basic mixture M1 is located in the first independent station 6A of the series and can be mounted on respective Cartesian type handling means 30 or anthropomorphic type handling means 34;

- with reference to the third and fourth embodiments, the at least one device 42 for suction of the basic mixture M1 is preferably positioned above and in correspondence with the first inclined extraction belt 14 (in a similar manner to the dispensing means 26 where present and to the second distribution means 8) and is also mounted on anthropomorphic handling means 36.

The at least one suction device 42 preferably comprises a duct 44 with a suction mouth 46 and connected to motorized suction means 48, such as for example a vacuum cleaner, as better visible in figures 2-4, 9-11, 16-18 and 25-27.

The duct 44 is conveniently constituted by a flexible pipe which accompanies the movement of the handling means 30, 34, 36 on which the at least one suction device 42 is mounted.

The apparatus 1 also comprises recovery means 50 of the aspirated basic mixture M1 connected to the at least one suction device 42 and associated with the first means 2 for distributing the basic mixture M1.

As better illustrated in figures 1, 3-4, 8, 10-11, 15, 17-18, 24 and 26-27, the recovery means 50 comprise at least one tank 52 for collecting the aspirated base mixture M1, the collection tank 52 being connected to the duct 44 of the at least one suction device 42.

The motorized suction means 48 of the type described above are positioned in correspondence with the collection tank 52 to generate a vacuum inside it.

Then, the base dough M1 is sucked up by the at least one suction device 42 in order to create the grooves G in the base dough layer M1 and falls by gravity into the at least one collection tank 52.

Conveniently, the at least one collection tank 52 is equipped at the bottom with a discharge mouth 54 for the basic mixture M1 sucked up and collected inside it, the discharge mouth 54 being equipped with a device for controlling the discharge of the basic mixture M1.

As illustrated schematically in figures 1, 3-4, 8, 10-11, 15, 17-18, 24 and 26-27, the device for controlling the discharge of the base mixture M1 from the at least one collection tank 52 is constituted for example by a rotary cell 56, or a rotary valve constituted by a rotating cylinder on the periphery of which a series of cavities are obtained.

The function of the rotary cell 56 is twofold, that is, to allow the release of the base mixture M1 collected in the at least one collection tank 52 in a controlled manner by varying the rotation speed of the cylinder and to keep the environment inside the tank 52 in which the depression is created separate from the external environment at atmospheric pressure.

The apparatus 1 comprises a further extractor belt 58 inclined upwards and positioned at the outlet of the at least one collection tank 52 in correspondence with the discharge mouth 54.

The additional extractor belt 58 is intended to convey the base mixture M1 discharged from the at least one collection tank 52 to the conveyor belt 18 of the first distribution means 2, in particular to a further crushing device 60 with counter-rotating rollers 62 which feeds the conveyor belt 18, as better visible in figures 1, 4, 8, 11, 15, 18, 24 and 27.

The base mixture M1 coming from the at least one collection tank 52 is crushed in the further crushing device 60 and distributed over the base mixture M1 coming from the supply line 12 at the conveyor belt 18.

Advantageously, the disintegrating roller 20 positioned between the conveyor belt 18 and the hopper 10 of the first distribution means 2 allows the two different base mixes M1 to be disintegrated and crushed, homogenising them and eliminating any clods.

In accordance with alternative embodiments not illustrated in the attached figures, it is also possible to provide for multiple suction devices (possibly arranged in succession) or multiple collection tanks operating simultaneously or alternatively, without thereby departing from the scope of protection of the present invention.

These measures may allow for the width of the grooves G to be increased within which to distribute the complementary mixture M2 to create the veins or to compensate for any partial blockages in the suction of a part of the basic mixture M1.

The following additional measures can also be adopted to avoid clogging and obstruction of the suction by the M1 base mix:

- use of a low-stickiness M1 base mix, limiting the quantity of resin contained in the M1 base mix or using a resin with a lower stickiness level;

- use of 48 motorized aspirators with greater power;

- use of 44 suction ducts with reduced length and/or increased diameter;

- arrangement of the intake ducts 44 along a vertical axis;

- provision of a cleaning system and/or a quick replacement system for the suction ducts 44.

Advantageously, the means 6 for forming the grooves G can comprise, in addition to the at least one suction device 42, means 64 for compacting the sides and for finishing the edges of the grooves G, better visible in figures 5, 12 and 19 with reference to the first, second and third embodiment of the apparatus.

It is observed that the fourth embodiment of the apparatus 1 differs from the third embodiment, in addition to the differences mentioned above, also in that it does not have the compaction means 64.

Such compacting means 64, where provided, are arranged downstream from the at least one suction device 42 of the base mixture M1 and upstream from the dispensing means 26 of the colorant D. Furthermore, the compacting means 64 are mounted on respective Cartesian type movement means 30 or anthropomorphic type movement means 34, 36 of the type described above with reference to the first, second and third embodiments.

In the first embodiment and in the second embodiment of the apparatus illustrated respectively in figures 1-7 and 8-14 the compacting means 64 are placed in a respective independent station 64A of the series located downstream with respect to the station 6A with the at least one suction device 42 and comprising a respective fixed conveyor belt 29.

The compacting means 64 may comprise at least one mushroom-shaped furrowing tool 66; in the context of this description, the expression "mushroom-shaped" means that the at least one furrowing tool 66 is provided with a stem 68, preferably having an inverted truncated-conical shape, and an upper plate 69.

The furrowing tool 66, in particular its shank 68, is capable of being moved laterally and alternately, by means of the Cartesian type movement means 30 or by means of the anthropomorphic type movement means 34, 36, from one side to the other with respect to the central trajectory passing through the furrow G, so as to increase the width of the furrows G previously defined by the suction created by the device 42.

The upper plate 69 has the function of retaining the base mixture M1, preventing it from being ejected, and of compacting the base mixture M1 at the edges of the grooves G.

In accordance with an alternative embodiment not illustrated in the attached figures, two or more furrowing tools may also be provided.

These furrowing tools could be arranged in succession, with the first furrowing tool being smaller than the subsequent ones, in order to increase the width of the furrows; alternatively, these furrowing tools could be independent of each other, in order to increase the productivity of the apparatus.

The at least one furrowing tool 66 described above may also comprise or operate in combination with a ploughshare-shaped tool having a swinging motion.

This ploughshare tool allows the previously created G furrows to be widened, compacting their sides, in order to avoid landslides on the sides of the G furrows before filling with the complementary mix M2.

The means 6 for forming the grooves G may also include means for the rapid replacement of the groove-making tools 66, of a known type and not illustrated in the attached figures.

The apparatus 1 also comprises a control unit, not illustrated in the attached figures, connected to the first means 2 for distributing the basic mixture M1, to the means 6 for forming the six grooves G, to the means 64 for compacting the sides of the grooves G, to the means 26 for dispensing the colourant D, to the second means 8 for distributing the complementary mixture M2, to the advancement means 28, 29 and to the Cartesian type movement means 30 or to the anthropomorphic type movement means 34, 36 described above, to regulate its operation.

In particular, the operation of the movement means 30, 34, 36 of the at least one suction device 42 is regulated so that the at least one suction device 42 follows trajectories corresponding to the veins to be created, or insists on predetermined areas of the base mix layer M1 to increase the width of the grooves G.

As anticipated, the present invention also relates to a process for creating veins in slabs produced starting from at least one basic mix M1 and at least one complementary mix M2.

The method preferably includes the following steps:

i) distribution of at least one layer of base mix M1 on a supporting surface 4;

ii) forming grooves G in the at least one layer of base mix M1 distributed on the supporting surface 4;

iii) distribution of the complementary mix M2 in the grooves G, the complementary mix M2 being intended to create the veins of the slabs.

Phase ii) of forming the grooves G in the at least one layer of base mixture M1 is carried out by suctioning the base mixture M1 in quantities and with paths corresponding to the grooves G to be created.

Advantageously, phase i) is performed by means of the first distribution means 2 of the apparatus 1 described above, phase ii) is performed by means of the at least one suction device 42 of the apparatus described above and phase iii) is performed by means of the second distribution means 8 of the apparatus 1 described above.

Preferably, the process also includes a recovery phase of the basic mixture M1 aspirated during phase ii) of forming the grooves G, the basic mixture M1 being aspirated and recovered so that it can be reused in phase i) of distribution of the basic mixture M1.

This recovery phase of the aspirated base mixture M1 is carried out using at least one collection tank 52 of the apparatus 1 described above.

The method may also include:

- a compaction phase of the sides of the furrows G, carried out downstream of the suction phase ii) and upstream of the phase iii) of distribution of the complementary mixture M2 in the furrows G;

- a phase of dispensing a liquid or powdered dye D onto the sides of the furrows G, preferably carried out downstream of the phase of compacting the sides of the furrows G and upstream of phase iii) of distribution of the complementary mixture M2 into the furrows G.

Conveniently, the compaction phase of the sides of the furrows G is carried out by means of the at least one furrowing tool 66 of the apparatus 1 described above and the dispensing phase of the dye D is carried out by means of the dispensing means 26 of the apparatus 1 described above.

From the above it is now clear how the apparatus, the process and the system of the present invention allow the intended purposes to be advantageously achieved.

In particular, the provision of at least one suction device for the basic mixture, possibly in combination with the means for compacting the sides of the grooves, allows the creation of particularly large and broad veins in the slabs, with widths equal to or greater than 30 cm.

The above mentioned measure allows at the same time to create the veins in the slabs with reduced processing times compared to the processes known in the sector and to vary the width of the veins in an inexpensive, rapid and flexible way.

Furthermore, the use of the dye sprayed on the sides of the grooves allows for the creation of veins with clear and well-defined contours compared to the body of the slab.

Claims (26)

Claims 1. Apparatus (1) for the creation of veins in slabs produced from at least one basic mix (M1) and at least one complementary mix (M2), the apparatus (1) comprising in succession: - first means (2) for distributing at least one layer of base mix (M1) on a support surface (4); - means (6) for forming grooves (G) in the at least one layer of base mixture (M1) distributed on said support surface (4); - second means (8) for distributing the complementary mixture (M2) in the grooves (G), the complementary mixture (M2) being intended to create the veins of the slabs; where the support surface (4) is placed in relative movement with respect to the first distribution means (2), the forming means (6) and the second distribution means (8); characterised in that said means (6) for forming the grooves (G) in the at least one layer of base dough (M1) comprise at least one device (42) for suctioning the base dough (M1). 2. Apparatus (1) according to the previous claim, characterised in that said at least one suction device (42) comprises a duct (44) with a suction mouth (46) connected to motorised suction means (48). 3. Apparatus (1) according to any of the preceding claims, characterised in that it comprises means (50) for recovering the aspirated basic mixture (M1) connected to said at least one suction device (42) and associated with said first means (2) for distributing the basic mixture (M1). 4. Apparatus (1) according to the preceding claim if dependent on claim 2, characterised in that said recovery means (50) comprise at least one tank (52) for collecting the basic mixture (M1) and connected to said duct (44), said motorised suction means (48) being positioned in correspondence with said at least one collection tank (52) to generate a vacuum inside the at least one collection tank (52). 5. Apparatus (1) according to the previous claim, characterised in that said at least one collection tank (52) is equipped with a discharge mouth (54) of the basic mixture (M1), said discharge mouth (54) being equipped with a device for controlling the discharge of the basic mixture (M1). 6. Apparatus (1) according to the previous claim, characterised in that said device for controlling the discharge of the basic mixture (M1) is a rotary cell (56). 7. Apparatus (1) according to any of the preceding claims, characterised in that said first means (2) for distributing the basic mixture (M1) comprise at least one hopper (10) suitable for receiving the basic mixture (M1) from a respective supply line (12) and a first inclined extraction belt (14) placed downstream and in a position below said at least one hopper (10). 8. Apparatus (1) according to the previous claim, characterised in that said first means (2) for distributing the basic mixture (M1) comprise at least one crushing device (16) with counter-rotating rollers (17) and a conveyor belt (18) interposed between said supply line (12) and said at least one hopper (10). 9. Apparatus (1) according to the preceding claim if dependent on claim 3, characterised by the fact that it comprises a further extraction belt (58) placed at the outlet of said at least one collection tank (52) and intended to transport the aspirated base mixture (M1) to said transport belt (18) of the first distribution means (2). 10. Apparatus (1) according to any of the preceding claims, characterised in that said means (6) for forming the furrows (G) comprise means (64) for compacting the sides and for finishing the edges of the furrows (G) arranged downstream with respect to said at least one device (42) for suctioning the basic mixture (M1). 11. Apparatus (1) according to the previous claim, characterised in that said compacting means (64) comprise at least one mushroom-shaped furrowing tool (66), said furrowing tool (66) being intended to be moved transversely and from one side to the other with respect to the direction of movement of the support surface (4) of the base mixture (M1). 12. Apparatus (1) according to claim 10, characterised in that said compacting means (64) comprise at least one ploughshare-shaped furrowing tool (66) equipped with a swinging movement. 13. Apparatus (1) according to any of the preceding claims, characterised in that it comprises means (26) for dispensing a colourant (D) onto the sides of the grooves (G), said dispensing means (26) being positioned downstream of said at least one suction device (42) and upstream of said second means (8) for distributing the complementary mixture (M2). 14. Apparatus (1) according to any of the preceding claims, characterised in that said second means (8) for distributing the complementary mixture (M2) comprise a dispenser consisting of a container (22) with an opening (24) for the release of the complementary mixture (M2). 15. Apparatus (1) according to any of the preceding claims, characterised in that said support surface (4) for the distribution of the at least one layer of base dough (M1) is constituted by the bottom wall of a temporary support (S), i.e. a tray or a mould. 16. Apparatus (1) according to the previous claim, characterised in that said at least one device (42) for suction of the basic dough (M1) and said second means (8) for distributing the complementary dough (M2) are placed in respective independent stations (6A, 8A), each of said stations comprising means (29) for advancing said temporary support (S). 17. Apparatus (1) according to any of claims 15 and 16, characterised in that said at least one suction device (42) and said second means (8) for distributing the complementary mixture (M2) are mounted on respective Cartesian type movement means (30) or on respective anthropomorphic type movement means (34). 18. Apparatus (1) according to any of claims 1-14, characterised in that said support surface (4) for the distribution of the at least one layer of base dough (M1) is constituted by the upper surface of a conveyor/extractor belt. 19. Apparatus (1) according to the preceding claim if dependent on claim 7, characterised in that said support surface (4) for the distribution of at least one layer of the base mixture (M1) is constituted by the upper surface of said first inclined extraction belt (14). 20. Apparatus (1) according to the previous claim, characterised in that said at least one suction device (42) and said second means (8) for distributing the complementary mixture (M2) are positioned above said first inclined extraction belt (14). 21. Apparatus (1) according to any of claims 19 and 20, characterised in that said at least one device (42) for suctioning the basic mixture (M1) and said second means (8) for distributing the complementary mixture (M2) are mounted on respective anthropomorphic (36) or Cartesian type movement means. 22. Apparatus (1) according to any of claims 18-21, characterised in that it comprises a second inclined extraction belt (38) located downstream from said first inclined extraction belt (14) and intended to deposit the base dough layer (M1) with the complementary dough (M2) in a temporary support (S). 23. Apparatus (1) according to the previous claim, characterised in that it comprises means (40) for rolling the base dough layer (M1) with the complementary dough (M2) placed between said first inclined extraction belt (14) and said second inclined extraction belt (38). 24. Plant for the production of slabs, in particular slabs with a veined effect, starting from at least one basic mix (M1) and at least one complementary mix (M2), which plant comprises in succession: - an apparatus (1) according to any of claims 1-23 for producing veins in a layer of base mix (M1) using the complementary mix (M2); - a station for compacting the mixtures (M1, M2) distributed on a temporary support (S); - a dough hardening station (M1, M2); - a transport line of the temporary support (S) with the mixtures (M1, M2) from said apparatus (1) to said compacting station and to said hardening station. 25. Procedure for the creation of veining in slabs produced from at least one basic mix (M1) and at least one complementary mix (M2), the procedure comprising the following phases: i) distribution of at least one layer of base mix (M1) on a supporting surface (4); ii) forming grooves (G) in the at least one layer of base mix (M1) distributed on the supporting surface (4); iii) distribution of the complementary mix (M2) in the grooves (G), the complementary mix (M2) being intended to create the veins of the slabs; characterised in that said phase ii) of forming the grooves (G) in the at least one layer of base mixture (M1) is carried out by suctioning the base mixture (M1) in quantities and with paths corresponding to the grooves (G) to be created. 26. Process according to the preceding claim, characterised by the fact that it comprises a phase of recovery of the basic mixture (M1) aspirated during said phase ii) of forming the grooves (G), the aspirated and recovered basic mixture (M1) being used during phase i) of distribution of the basic mixture (M1) in subsequent processes.