EP4662040A1

EP4662040A1 - Device for glazing objects such as ceramic slabs and tiles

Info

Publication number: EP4662040A1
Application number: EP24703447.3A
Authority: EP
Inventors: Antonella DOLCINI; Carla ZOBOLI
Original assignee: Individual
Current assignee: Individual
Priority date: 2023-02-09
Filing date: 2024-02-05
Publication date: 2025-12-17
Also published as: IT202300002250A1; WO2024165965A1

Abstract

Device for glazing objects such as ceramic slabs and tiles, with at least one glaze dispensing unit (10), which is located above the conveying surface (20) of the objects and comprises: a hollow base body (13) having a series of glaze dispensing holes (12) in its lower wall (11); a blocking shuttle (2) driven by an adjustable-stroke actuator (5) to slide vertically (11) inside the hollow base body (13). During a glaze dispensing phase, the blocking shuttle (2) performs alternately a downward stroke to a position where it is not in contact with the lower wall (11) but raised slightly above it, and an upward return stroke. Lateral spacer elements protruding from the blocking shuttle (2) are in contact with the lateral walls of the base body (13), the gaps between the spacer elements allowing the free circulation of glaze therethrough. To interrupt the flow of glaze out of the unit (10), the blocking shuttle (2) is brought in contact with the lower wall (11), thereby blocking all the holes (12).

Description

DEVICE FOR GLAZING OBJECTS SUCH AS CERAMIC SLABS AND TILES

DESCRIPTION

The invention concerns a device for glazing objects.

Specifically, but not exclusively, the invention finds a useful application for glazing in the ceramic industry, mainly for the production of tiles and slabs intended for covering floors or walls in construction activities.

Glazing, consisting of the application of a continuous and as uniform as possible layer of glaze to surfaces intended, for example, to subsequently receive a decoration, is a part of the process to produce ceramic slabs or tiles which is normally carried out on the line for the production thereof, where the application of the glaze is performed on the products while they are moving.

A first technique, known as spray glazing, consists in using glazing stations made up of glazing booths of various kinds arranged along the line, at each one of which the spray glaze is sprayed onto the surface of the tiles and slabs in transit. The adoption of actual booths is dictated by the need to contain the spray glaze within an environment envisaged strictly for carrying out the operation, preventing the dispersion thereof into the environment. The surface glazing result is good, but can be economically improved due to the fact that during the process, a large part of the spray glaze is not actually used (from 30% to over 50% of the glaze dispensed, depending on the glazing technique used) because the said glaze cannot be applied to the slabs or tiles and must therefore be suctioned up to keep the application booth clean and to prevent the dispersion of the spray glaze mist into the environment, with the consequent need to be intercepted and conveyed with a special system within which the said mist is lowered and subsequently disposed of.

These glazing techniques are used in the national ceramic industry, covering around 90% of the production of tiles and slabs (compared to an estimated

SUBSTITUTE SHEET (RULE 26) approximately 60% in the rest of the world), mainly in the production of porcelain stoneware.

Another glazing technique is the continuous curtain technique according to which a veil of glaze is generated whose width depends on the size of the tiles and slabs to be glazed, wherein the latter, carried on a conveyor system, move into the veil of glaze, acquiring part thereof which then forms a layer on the surface.

There are various embodiments used: veils, bells, dies, etc.

Also in this case, the quality of the glazing carried out is more than good, but precisely because of the application methods, the amount of glaze that must be dispensed is considerable and therefore not particularly suitable for the types of tiles and slabs currently most produced by the ceramic industry, as - in the case of porcelain stoneware - modest amounts of glaze need to be applied.

It is estimated that use of these glazing techniques makes up approximately 10% of the production in the national ceramic industry and a little more, at between 30% and 40%, in the rest of the world.

However, another glazing technique still under study and development is digital ink jet glazing, which is a latest generation technology derived directly from ink jet or digital printing/decoration and is now widespread in the ceramic industry for making decorations of all kinds. However, some obstacles in the use of this technology for glazing must still be overcome. These certainly include the cost of the glaze, which is 6-8 times higher than that normally used with conventional glazing techniques (this is due to the higher production cost of the glazes used in the ink jet heads and the media necessary in the composition thereof, which is attributable to the cost of the extra-fine grinding required to prevent the heads clogging, and of the indispensable chemical media required to preserve the heads). The latter, among other things, are particularly polluting when burned in the kiln and this condition has prevented the spread of this glazing technique, given that the amounts of material applied would be much greater than for decoration.

Another obstacle is the overall cost of the machine, which is decidedly higher than those of machines which use commonly known tile glazing technologies.

Other glazing methods are based on the idea of having a glazing unit essentially comprising a glaze applicator bar positioned transversally to the tile advancement direction and from whose lower face many continuous flows pour out (through a long series of small holes), or take the form of glazes dispensed with various hydraulic and mechanical dispensing methods.

These methods and the machines therefor have not yet succeeded in taking hold because they are unable to guarantee optimal quality aesthetic results (specularity of the glazed surface) due in particular to the limit imposed by the minimum distance of on average 2 to 3 mm between each hole and the hole immediately adjacent thereto; this condition often tends to produce unwanted lines on the surface. The only way to mitigate this effect is to increase the amount of glaze in order to douse the surface and therefore improve coverage, but with obvious problems such as increased costs, without forgetting that (as mentioned above for certain products, such as porcelain stoneware for example) this increase in the thickness of the glaze is not only undesirable for the product but also intolerable in production. The non- modular approach of these technologies has also highlighted limits concerning adaptation for extra-large slabs.

The present invention aims to overcome the drawbacks and limits of the known art by means of a new glazing device which is economically convenient in terms of both plant and equipment cost and the cost of producing the products (slabs, tiles) and which has a low environmental impact which depends not only on the quality of the components but also on the amount of glaze employed and consumed compared to the currently widespread and used prior art systems described.

A further object of the present invention is to create a glazing device which has a modular structure to be used for all kinds of sizes.

The object of the present invention is therefore to create a glazing device as described in the description and illustrated in the annexed figures and in accordance with the claims.

The most obvious advantages of this new invention are that the invention:

-is equal to or improves the degree of glaze coverage of the surface with respect to the current methods in use;

-is simple for operators in the industry to use;

-requires an affordable investment with respect to commonly known technique in use today;

-makes the new glazing process economically sustainable, thanks to the use of glazes with characteristics and costs that are very similar to the current ones (and not 6 to 8 times higher, like those used for ink jet technology);

- produces significant glaze savings (at least 30%) with respect to the glazing method which is most widespread at present (spray application);

- produces considerable savings due to the abatement and disposal of the amount of waste, together with the indisputable and much more important beneficial results for the environment;

- requires less water use, due to both the grinding (over 30%) and the frequent washing that spray booths require;

- curbs emissions of harmful combustion gases into the atmosphere.

Further characteristics and advantages of the present invention will emerge more clearly in the detailed description that follows of certain preferred embodiments illustrated, in the form of non-limiting examples, in the appended figures, wherein: - Figure 1 shows, with reference to a first embodiment, a schematic vertical elevation view, partially sectioned along a vertical plane and perpendicular to the direction of motion, of the mobile conveying surface for conveying the tiles to be glazed;

Figure 2 shows part of Figure 1 in a top-down plan view;

Figure 3 shows, on an enlarged scale, part of Figure 1 ;

Figure 4 shows, on an enlarged scale, a sectional view taken according to plane line ll-ll in Figure 3;

Figure 5 shows a schematic top-down plan view of a second embodiment;

Figure 6 shows a schematic sectional view taken according to plane line Ill-Ill in Figure 3.

With reference to the appended figures, 1 denotes, overall, a glaze dispensing device consisting of a single glaze dispensing unit 10 made in accordance with the invention, which is arranged in a transverse orientation at a pre-established distance above the resting surface of a mobile conveying surface, denoted 20, on top of which tiles to be glazed 30 are placed and conveyed in an orderly manner.

In this case, the mobile conveying surface 20 is constituted of a plurality of common conveyor belts 21 .

Each glaze dispensing unit 10 comprises, in turn, a base body 13 with a hollow interior which is provided with a lower wall 11 endowed with at least one series of aligned holes 12 envisaged to dispense the glaze (in the form of microdroplets) on command.

An interception/blocking shuttle 2 is guided so as to slide in a perpendicular direction to the lower wall 11 , operated by an external actuator 5 inside a fluid-tight chamber 6, which is constituted of the hollow part of the base body 13 and is sealed at the top thereof by a lid 3. The interception/blocking shuttle 2 is controlled by the external actuator 5 so as to perform an alternating translational motion consisting of an operating (or forward) stroke originating in an upper position, at which the lower surface thereof is raised and at a pre- established distance from the upper surface of the lower wall 1 1 , endowed with the holes 12, of the base body 13, to a lower end position in which the said lower surface is in contact, under a pre-established pressure, with the said lower wall 1 1 , thereby blocking all the holes 12, and of a return stroke wherein the interception/blocking shuttle 2 is called back from the said lower position to the said upper position.

The interception/blocking shuttle 2, and likewise the internal walls of the hollow part of the base body 13, are made and/or coated with wear-resistant materials with a low friction coefficient to facilitate the alternating motion of the shuttle 2. In particular, the interception/blocking shuttle 2 features opposing lateral surfaces equipped with protruding spacer elements, shaped and arranged to come into contact - with pre-established clearance - with the opposing lateral walls of the base body 13, leaving volumes clear to allow the free circulation of the glaze inside the chamber 6. The bottom surface of the interception/blocking shuttle 2 intended to come into contact with the wall 1 1 has an overall convex form and is furthermore structurally equipped with a layer of soft material in order to ensure non-destructive contact which promotes sealing to close the holes 12 present in the lower wall 1 1 .

The holes 12, which are calibrated and have the same diameter, are arranged in a reciprocally aligned and in an equally spaced manner. The pitch of the holes and diameter thereof are sized according to the nature of the glaze and the amounts to be applied. The pitches between the holes 12 can range from approximately 0.5 mm to 3 mm, with a most frequently used range being 1 mm to 2 mm. The diameters of the said holes range from 0.1 mm to 0.6 mm with a more frequent range being from 0.2 mm to 0.4 mm for the glazes most commonly used in the ceramic industry depending on the weight ratio (amount of glaze per unit of surface area) to apply and the transit speed of the tiles or slabs 30. The lid 3, which has the function of hermetically sealing the fluid-tight chamber 6, features connections 7 and 8 for, respectively, the inlet and outlet of the glaze and houses, at the top thereof, an external actuator 5 which penetrates the chamber 6 via the part consisting of a shaft 25 which is integral with the shaft 15.

The shaft 15 of the actuator 5 is connected to the shaft 25 by a coaxial mechanical connection which facilitates the coupling and uncoupling of the actuator 5 to and from the lid 3.

The shaft 25 is, in fact, connected in a sealed manner via a through-hole made in the lid 3.

Between the shaft 25 and the hole envisaged in the lid 3, a special ringshaped sealing membrane 4 fulfils this purpose, being made of an elastically deformable sealing material which allows axial travel of the control shaft 25 with respect to the base body 13 and consequently the alternating translational motion of the interception/blocking shuttle 2 which is fixed to the lower end of the control shaft 25.

More specifically, the sealing membrane 4 is secured, around the external diameter, to the lid 3 and, around the internal diameter, to the shaft 25.

The sealing system thus created allows a vertical movement of the control shaft 25 to be performed with respect to the base body 13 and consequently movement of the interception/blocking shuttle 2 with respect to the holes 12 performing a stroke that can be chosen between an end position in contact with the lower wall 11 (with complete mechanical blocking of the holes 12) in the presence of glaze pressure values between 0.1 bar and 1.5 bar, or the lower end positions not in direct contact as slightly raised off the lower said wall 11 , ranging from 0.05 mm to 2 mm. More specifically, the actuator 5 is an adjustable-stroke linear actuator arranged to correspondingly generate a stroke which can be adjusted, on command, so as to reach the said lower end position defined by the condition of being in contact with the lower wall 1 1 and which achieves the mechanical closure of the holes 12, through to the condition of being set to operate, during the active dispensing phase, so as to reach, at the lower end of its travel, positions not in direct contact but slightly raised off the said lower wall 11 , with distances of between 0.05 mm and 2 mm depending on the needs (essentially the chemical/physical characteristics of the glaze and the pressure). This is done by operating with oscillation frequencies ranging from 1 Hz to 1200 kHz, with a more frequent range being from 100 Hz to 600 Hz for the most commonly used glazes.

The possibility of adjusting the stroke by setting the end position or the lower stroke limit slightly raised off the lower wall 11 , at a distance of between 0.05 mm and 2 mm, allows the formation of the microdroplets to be modulated simply and effectively, while also offering the advantage of preserving the lower wall 1 1 of the base body 13 and the overall convex lower surface of the interception/blocking shuttle 2 from wear.

During the glaze dispensing action, the lower surface of the interception/blocking shuttle 2 does not come into contact with the lower surface 11. The contact position, with the consequent closure of the calibrated holes 12, is, in fact, reached in the non-dispensing condition which, on the line, occurs in the interval (gap) between one tile and the next. The entire dispensing unit 10, via the base body 13, is supported by and constrained to a mobile frame in the form of a horizontal bar 14 which is positioned above the mobile conveying surface 20 and is positioned transversally with respect to the direction of the conveying motion thereof. The mobile frame in the form of a bar 14 is secured to a fixed frame 16 in an axially sliding manner and is commanded to perform small axial translations in both directions transversely to the direction of the mobile conveying surface 20 forwards motion. The alternating transverse motion is imparted to the barshaped mobile frame 14 by a linear actuator 7 fastened to the frame 16. The linear actuator 7 is similar to the linear actuator 5. The alternating motion of the dispensing unit 10 is synchronised with the forwards motion of the tiles to be glazed, as well as with the alternating motion of the interception/blocking shuttle 2.

The device dispenses microdroplets of glaze through the holes 12. The microdroplets are produced by the action of the interception/dispensing shuttle 2 which, interacting with the bottom wall 11 , forces the glaze through the holes 12. This occurs at the pre-established frequency set for the oscillation (alternating motion in the vertical direction) of the shaft 15, which depends - in any case - on the aforesaid factors and in particular on the chemical-physical characteristics of the glazes, the dimensions of the holes 12, and the conveying speed of the tiles 30.

The full (optimal) covering of the entire surface to be glazed is achieved by arranging transversal movements of the rows of holes 12 so as to position microdroplets in the portions of the surface not directly covered with a fixed matrix application, which follows longitudinal rows parallel to the direction of the forwards motion of the tiles 30.

In particular, the small transversal movements are coordinated to create the said arrangement of droplets corresponding to half of the pitch, i.e. half of the distance between two consecutive holes.

The transversal oscillation of the dispensing device 1 is synchronised with the speed of the conveying surface 20 with the result that transverse rows of microdroplets alternating with individual rows of microdroplets obtained with the configuration moved transversely by half of the pitch are dispensed and moved transversally and then deposited on the individual tiles or slabs 30.

The part in Figure 2 shows, schematically, the points of impact of the droplets on the surface during the glazing stage, wherein the transverse rows of droplets deposited by the glaze dispensing unit can be detected when the latter is in the starting position of the forward stroke of the alternating motion thereof, the said rows alternating with the rows of microdroplets deposited when the stroke limit is reached.

The operating modes of the device are set so as to be synchronised with the motion conveying the tiles or slabs 30 which require discontinuous operation. During the non-active stage, in which glaze is not dispensed ...

When the correct operating position is reached to allow glazing of the tile underneath the glazing device, the interception/locking shuttle 2 is raised by the linear actuator 5 to the pre-selected stroke limit position and lowered from there to the pre-set lower stroke limit (for example, slightly raised off the lower wall 1 1 by a distance of between 0.05 mm and 2 mm) in order to act on the glaze, generating microdroplets.

The actuator 5 creates an alternating motion with a set frequency of between 1 Hz and 1200 Hz, depending on the size and speed of the tile or slab.

In a second embodiment, designed for the glazing of large formats, the solution is used to construct a glaze dispensing bar 100 consisting of the assembly of some (five) glaze dispensing unit 10, each one made in accordance with the invention, arranged with a transversal orientation at a pre-established distance above the resting surface of a mobile conveying surface, denoted 20, on top of which tiles to be glazed 30 are placed and conveyed in an orderly manner. In this case, the mobile conveying surface 20 is constituted of a plurality of common conveyor belts 21 .

Each glaze dispensing unit 10, in turn, features the characteristics of the embodiment illustrated previously and comprises: a base body 13 with a hollow interior, equipped with a lower wall 1 1 which is endowed with a series of holes 12 designed to let the glaze flow out on command (in the form of microdroplets) and an interception/blocking shuttle 2, guided so as to slide in a perpendicular direction to the lower wall 1 1 , operated by a linear actuator 5 inside a fluid-tight chamber 6 consisting of the hollow part of the base body 13 sealed at the top by a lid 3. The interception/blocking shuttle 2 is controlled by the external actuator 5 so as to perform an alternating translational motion consisting of an operating or forward stroke originating in an upper position, at which the lower surface thereof is raised and at a pre-established distance from the upper surface of the lower wall 11 , endowed with the holes 12, of the base body 13, to a lower position in which the said lower surface is in contact with the said lower wall 1 1 , thereby blocking all the holes 12, and of a return stroke wherein the interception/blocking shuttle 2 is called back from the said lower position to the said upper position.

The individual dispensing units 10 are carefully positioned so as to achieve perfect coverage of the surface of the tile 200 to be glazed. This means that the mutual positioning of the two dispensing units arranged at the rear in a transverse direction and parallel to the three front dispensing units is achieved by aligning the said units so that the rows of microdroplets produced thereby are aligned in the same direction horizontally with the microdroplets deposited by the front dispensing units, maintaining the same pitch across the entire width of the tile 30.

According to another embodiment, not illustrated in the appended figures, a device according to the invention is equipped with a lower wall 1 1 in which at least two mutually parallel series of holes 12 are provided, the said holes being designed to allow the glaze to flow out on command.

The said series of holes 12 are mutually parallel and arranged mutually staggered by half the pitch (i.e. the distance between any two adjacent holes) of the holes.

The lower convex surface of the interception/blocking shuttle 2 is sized so as to block the holes 12 in both of the said series once the said interception/blocking shuttle has been activated so as to move into the lower blocking position. A further embodiment (not illustrated in the appended figures) envisages a unit in accordance with the invention which includes a first glaze dispensing unit 10 and a second glaze dispensing unit 10 which are positioned with the series of holes 12 therein arranged parallel with transversal orientation, mutually spaced by a pre-established distance, but mutually staggered by half the pitch in the said transversal dimension, which is perpendicular to the motion of the slabs or tiles 30.

A final embodiment comprises the use of a first glaze dispensing bar 100 and a second glaze dispensing bar 100 which are positioned with the series of holes 12 therein arranged parallel with transversal orientation and mutually spaced by a pre-established distance. The two series of holes are arranged mutually staggered by half the pitch in the said transversal dimension, which is perpendicular to the motion of the slabs or tiles 30.

The main advantages offered by the invention are that surface coverage is improved and, above all, the thickness of the glaze applied is controlled, thereby reducing glaze consumption as glaze delivery is activated only when the surface of the individual slab or tile to be glazed is placed in the position covered by the holes 12.

Claims

1 ). A device for glazing objects such as ceramic slabs and tiles comprising, operating in association with a mobile conveying surface (20) for conveying objects to be glazed, such as slabs and tiles (30) and the like, at least one glaze dispensing unit (10), which is located at a pre-established distance above the said mobile conveying surface (20) and comprises, in turn, a base body (13) with a hollow interior, equipped with a lower wall (11 ) which is endowed with at least one series of holes (12) arranged to dispense the glaze on command; an interception/blocking shuttle (2) guided so as to slide in a perpendicular direction to the lower wall (1 1 ), operated by an actuator (5) inside a fluid-tight chamber (6), which is constituted of the hollow part of the base body (1 ) and is sealed at the top thereof by a lid (3), characterised by the fact that the interception/blocking shuttle (2) features opposing lateral surfaces equipped with protruding spacer elements, shaped and arranged to come into contact - with pre-established clearance - with the opposing lateral walls of the base body 13, leaving volumes clear to allow the free circulation of the glaze inside the chamber 6, the interception/blocking shuttle (2) being controlled by the actuator (5) so as to perform an alternating translational motion which is composed, during the active dispensing step, as follows: of an outward stroke originating from an upper position - at which the lower surface thereof is located at the upper stroke limit, at a pre-established distance from the lower wall (1 1 ), endowed with the holes (12), of the base body (1 ) - and descending to a pre-set lower stroke limit position, at which the said lower surface is positioned higher with respect to the said lower wall (11 ), the said lower stroke limit position being not in contact with the lower wall (11 ), and of a return stroke from the said lower stroke limit position below the said upper stroke limit position; there being envisaged, during the inactive step in which the glaze is not dispensed, the reaching of a stroke limit switch at which the interception/blocking shuttle(2) comes into contact with the lower wall (11 ), with the consequent closure of the calibrated holes (12).

2). A device according to Claim 1 characterised by the fact that the entire dispensing unit (10) is supported and constrained, by means of the base body (13), to a mobile frame (14), which is located transversely to the direction of motion of the mobile conveying surface (20), is coupled to a fixed frame (16) in an axially sliding manner, and is controlled so as to perform small axial translations in both directions transversely to the direction of the forward movement of the mobile conveying surface (20).

3). A device according to Claims 1 or 2 characterised by the fact that the interception/blocking shuttle (2) and likewise the internal walls of the hollow part of the base body (13) are made of and/or lined with wear-resistant materials.

4). A device according to Claim 3 characterised by the fact that the interception/blocking shuttle (2) has the lower part thereof endowed with an overall convex form and has a protective layer made of a soft material so as to ensure non-destructive contact and which facilitates the fluid-tight closure of the holes (12).

5). A device according to Claim 4 characterised by the fact that the holes (12) are arranged aligned and mutually equidistant, the pitch of the holes and diameter thereof being sized according to the nature of the glaze and the amounts to be applied with the pitches of the holes (12) ranging, approximately, from 1 mm to 3 mm, and the diameter of the said holes ranging from 0.1 mm to 2 mm for the glazes that are most commonly used in the ceramic industry.

6). A device according to Claim 5 characterised by the fact that the lid (3), which has the function of hermetically sealing the fluid-tight chamber (6), has the connections (7) and (8) for, respectively, the inlet and the outlet of the glaze and houses, on the top thereof, the actuator (5), which penetrates the chamber (6) by means of the part of the shaft (15) constituted of a shaft (25) to whose lower end the interception/blocking shuttle(2) is stably connected, there being a sealing membrane (4) envisaged which operates between the said shaft (25) and the hole envisaged in the lid (3) within which the said shaft is housed.

7). A device according to Claim 6 characterised by the fact that the sealing membrane (4) has a ring configuration and is made of an elastic sealing material which allows the axial movement of the drive shaft (25) with respect to the base body (1 ) and consequently the alternating translational motion of the interception/blocking shuttle (2) which is fixed to the lower end thereof.

8). A device according to Claim 7 characterised by the fact that the sealing membrane (4) is constrained, at the external diameter thereof, to the lid (3) and, at the internal diameter thereof, to the shaft (25); the sealing system thus created allows the performance of a vertical movement of the drive shaft (25) with respect to the base body (1 ) and consequently of the interception/blocking shuttle (2) with respect to the holes (1 ) with a stroke length which may be chosen from a range of 0.05 mm to 2 mm in the presence of glaze pressure values of between 0.1 and 1 .5 bar.

9). A device according to Claim 8 characterised by the fact that the actuator (5) is a linear actuator and is designed to generate, correspondingly, a stroke which is adjustable on command starting from a first condition involving contact with the lower wall 11 , through the mechanical closure of the holes 12, and reaching a condition in which they said actuator may be set with the lower end of the stroke within a range of 0.05 mm to 2 mm, depending on the needs, and operating at frequencies ranging from 1 Hz to 1200 kHz, with the most frequent range being from 100 Hz to 600 Hz for the most commonly used glazes.

10). A device according to Claim 9, characterised by the fact that the alternating transverse motion is imparted to the said mobile frame, which is in the form of a bar (14), by a linear actuator (7) fixed to the fixed frame (16); the alternating motion of the dispensing unit 10 being synchronised with the forwards motion of the tiles to be glazed (30), as well as with the alternating motion of the interception/blocking shuttle (2) and with the forward motion mode of the mobile conveying surface (20).

11 ). A device according to Claim 10, characterised by the fact that the said lower wall (1 1 ) is endowed with two mutually parallel series of holes (12) arranged to dispense the glaze on command, the two series of holes (12) being mutually parallel and arranged mutually staggered by half of the pitch of the holes and the lower convex surface of the interception/blocking shuttle (2) being sized so as to block the holes 12 in both of the said series once the said interception/blocking shuttle has been activated so as to move into the lower operating position thereof.

12). A device according to Claim 10 characterised by the fact that the said device comprises a first glaze dispensing unit (10) and a second glaze dispensing unit (10), which are positioned with the relative series of holes (12) arranged mutually parallel at a pre-established distance, with a transversal orientation, and mutually staggered by half of the pitch of the holes in the said transversal dimension with respect to the motion of the slabs or tiles (30).

13). A device according to Claim 10 characterised by the fact that the said device comprises a first glaze dispensing bar (100) and a second glaze dispensing bar (100), which are positioned with the relative series of holes (12) arranged mutually parallel at a pre-established distance, with a transversal orientation, and mutually staggered by half of the pitch of the holes in the said transversal dimension with respect to the motion of the slabs or tiles (30).