Apparatus for decorating ceramic articles

Abstract

Apparatus (1) for decorating ceramic articles, comprising: at least one machine (2) for decorating ceramic articles, the machine comprising a plane for conveying ceramic articles and at least one glaze dispensing device (4) for dispensing glaze on said ceramic articles; wherein the machine (2) comprises at least one internal reservoir (5) adapted to contain glaze (S) to be applied to the ceramic article and hydraulically connected to the glaze dispensing device (4), at least one glaze preparation tank (8) hydraulically connected to the internal reservoir (5), wherein the glaze preparation tank (8) is provided with at least one measuring device (10) for measuring the density and / or viscosity of the glaze contained in the preparation tank itself, transfer means (7, 9) are provided for transferring the glaze (S) from the glaze preparation tank (8) to the internal reservoir (5), and at least one electronics unit (11) operatively connected to at least the measuring device (10), and an electronic unit (11) for identifying a detected density and / or viscosity value (DC) of the glaze contained in the preparation tank (8) and operatively connected to the transfer member (7, 9), the electronic unit (11) being adapted to command the glaze (S) to be sent from the preparation tank (8) to the internal reservoir (5) when the detected density and / or viscosity (DC) corresponds to the reference density and / or viscosity value (DR).

Description

Technical Field

[0001] The present invention relates to a device for decorating ceramic products. Background Art

[0002] During the decoration of ceramic articles, such as tiles, the density and viscosity of the glazes used play an important role, since they significantly influence the way the glaze itself is applied and the quality of the decoration obtained.

[0003] For this reason, it is easy to understand how important it is to obtain correct measurements of these properties in order to be able to optimize the subsequent stage of applying the glaze on the article to be decorated.

[0004] In this regard, such measurements are currently performed either manually by extremely complex and expensive tools, or by empirical tools of the Ford Cup type.

[0005] Specifically, the latter tool comprises a hollow body provided with an inlet opening and an outlet opening of a working liquid whose viscosity is to be measured and having a predetermined volume. The tool can uniquely determine the viscosity of the liquid flowing through by measuring the time required for the liquid to flow completely through the outlet opening.

[0006] However, the use of these tools is not without disadvantages.

[0007] In fact, taking measurements manually often returns inaccurate and unreliable results.

[0008] In fact, it is easy to understand that since the measurements are done completely manually, the possibility of errors or inaccuracies by the person using the tool will be very high.

[0009] In this case, the resulting error will continue to affect all subsequent activities involving the use of the measured parameters, thus jeopardizing their normal success.

[0010] If, in addition, the density of the glaze differs from that suitable for a particular technical operation, the operator should add the appropriate amount of one or more liquids to bring it to the desired density.

[0011] However, this proved to be a particularly complex task with a high probability of operator error.

[0012] In the decoration process of ceramic articles, it has also proven to be of the utmost importance to have on hand and therefore readily available a sufficient amount of glaze with the required density and viscosity characteristics, so as to meet the production requirements without causing unnecessary machine downtime. In fact, machines for decorating ceramic articles of known type include means for dispensing glaze, which must be properly supplied during the production phase.

[0013] In fact, it seems obvious that a glaze to be applied to a ceramic article must be prepared in advance and that, if not used, its rheological properties may change over time, for example due to evaporation of part of its aqueous component.

[0014] Document EP3421203A1 describes a device for decorating ceramic articles, which involves preparing a glaze to be distributed on the product with a predetermined density. Additional devices for decorating ceramic articles are known from EP1127667A2, JPH09328380A and SU1126562A1. Summary of the invention

[0015] The main object of the invention is to design an apparatus for decorating ceramic articles which is capable of quickly, automatically and accurately preparing a glaze having the desired rheological properties and which can be used to meet production requirements.

[0016] Within this aim, an object of the invention is to devise a device that allows simplifying the glaze density correction operation by freeing up as much as possible the skills and attention of the operator.

[0017] Another object of the present invention is to devise a device for decorating ceramic articles which overcomes the aforementioned drawbacks of the prior art within the framework of a simple, rational, easy and effective use and cost-effective solution.

[0018] According to the present invention, an apparatus for decorating ceramic products comprises: a machine for decorating ceramic products, the machine being provided with a plane for conveying ceramic products and with at least one glaze dispensing device, wherein the machine comprises at least one internal reservoir suitable for containing glaze to be applied to the ceramic products and being hydraulically connected to the glaze dispensing device, and at least one glaze preparation tank being hydraulically connected to the internal reservoir, wherein the preparation tank is provided with at least one measuring device for measuring the density and / or viscosity of the glaze contained in the preparation tank itself.

[0019] Preferably, transfer means are provided for transferring the glaze from the preparation tank to the internal reservoir.

[0020] Preferably, the device comprises at least one electronic unit operatively connected at least to the measuring means in order to identify the detected density and / or viscosity value of the glaze contained in the preparation tank.

[0021] Preferably, the electronic unit is operatively connected to the transfer member and is suitable for commanding the sending of the glaze from the preparation tank to the internal reservoir when the detected density and / or viscosity corresponds to a reference density and / or viscosity value.

[0022] Preferably, the apparatus comprises at least one glaze supply tank located between the internal reservoir and the preparation tank and hydraulically connected thereto.

[0023] Preferably, the transfer member comprises a first transfer member for transferring the glaze from the supply tank to the internal reservoir and a second transfer member for transferring the glaze from the preparation tank to the supply tank.

[0024] Preferably, the internal reservoir comprises access means for accessing the glaze level therein, and the electronic unit is operatively connected to these access means and to the first transfer means.

[0025] Preferably, the electronic unit is programmed to command the first transfer member itself to send an amount of glaze from the supply tank to the internal reservoir that is proportional to the drop in the glaze level detected by the acquisition member relative to a predetermined maximum level.

[0026] Preferably, the machine comprises a pressurizing member adapted to maintain the pressure within the internal reservoir substantially equal to a predetermined value.

[0027] Preferably, the glaze dispensing device comprises at least one internal hollow container for collecting glaze to be applied to the ceramic object and provided with at least one set of through holes for the glaze to flow out, at least one roller arranged in the container and capable of rotating around a relevant axis, wherein the volume located between the inner wall of the container and the roller defines a glaze receiving chamber, which is hydraulically connected to the internal reservoir by means of a glaze supply circuit, the holes protruding inwardly into the receiving chamber, and the roller is provided with at least one set of protrusions suitable for opening and closing the holes in a sequential and cyclic manner during the rotation of the roller itself to allow and prevent the glaze from flowing out of the container, respectively.

[0028] Preferably, the supply circuit includes at least one supply section connected to the internal reservoir, at least one pair of glaze transfer sections connected to two axial ends opposite to each other of the accommodating chamber, and at least one return section connected to the supply tank, and includes a first valve member, which is located between each transfer section, the supply section and the return section in the transfer section and is capable of being operated to selectively set each transfer section in the transfer section to be connected to the internal reservoir and the supply tank.

[0029] Preferably, the electronic unit is operably connected to the first valve members and is programmed to activate one of the first valve members within a predetermined time interval so as to set the supply section to communicate with the associated transfer section, and to activate another of the first valve members so as to set the associated transfer section to communicate with the return section.

[0030] Preferably, the supply tank comprises a sensor member adapted to detect the glaze level therein, and the electronic unit is operably connected to the sensor member and programmed to command activation of the second transfer member when the glaze level in the supply tank reaches a predetermined minimum value and the detected density and / or viscosity of the glaze in the preparation tank is equal to the reference density and / or viscosity.

[0031] Preferably, the measuring device comprises

[0032] at least one hollow body defining a glaze containing compartment, the glaze containing compartment comprising at least one inlet port and at least one outlet port for the glaze, wherein the outlet port has a smaller conveying cross section than the inlet port and is arranged on the top of the preparation tank for draining the glaze therein;

[0033] a weighing member associated with the hollow body;

[0034] a detection member for detecting the glaze level in the containing compartment;

[0035] wherein the electronic unit is operatively connected to the weighing member and the detecting member, the latter being adapted to send to the electronic unit at least a first signal related to the weight of the hollow body when the glaze contained in the containing compartment reaches a first predetermined level, and to send at least a second signal related to the weight of the hollow body when the glaze reaches a second predetermined level below the first predetermined level, the electronic unit being configured to calculate a glaze weight value corresponding to a difference between the first signal and the second signal, and to calculate a density of the glaze depending on the calculated weight value and a volume of the containing compartment located between the first predetermined level and the second predetermined level;

[0036] and wherein the electronic unit comprises at least one programmable memory having a volume value of the receiving compartment at least between a first predetermined level and a second predetermined level;

[0037] At least one timer is associated with the electronic unit, the latter being configured to calculate a time interval elapsed between the sending of the first signal and the sending of the second signal and to calculate the glaze viscosity identification value depending on the calculated time interval.

[0038] Preferably, the second transfer member comprises at least one transfer conduit and a second pumping member arranged along the transfer conduit, and the device is provided with at least one hydraulic circuit comprising:

[0039] a second transfer member;

[0040] a second valve member disposed along the transfer conduit and actuated to selectively send the glaze to the supply tank or the first conduit, the first conduit being designed and adapted to send the glaze contained in the preparation tank into the hollow body;

[0041] at least one second conduit adapted to introduce an additional liquid having a predetermined density and / or viscosity into the preparation tank;

[0042] The programmable memory contains at least one reference density and / or viscosity value and a density and / or viscosity value of the additional liquid, and the electronic unit is programmed to compare the reference density and / or viscosity value with the detected density and / or viscosity and to command the introduction of additional liquid into the preparation tank when the detected density and / or viscosity differs from the reference density and / or viscosity.

[0043] Preferably, the electronic unit is programmed to calculate an updated density and / or viscosity value depending on the amount of additional liquid introduced into the preparation tank and to command the introduction of additional liquid into the preparation tank when the updated density and / or viscosity value differs from the reference density and / or viscosity value.

[0044] Preferably, the second valve member is operably connected to an electronic unit configured to activate the second valve member itself when the detected density and / or viscosity value or the updated density and / or viscosity value corresponds to the reference density and / or viscosity value so as to allow the glaze to be delivered to the supply tank.

[0045] Preferably, the electronic unit is configured to calculate the amount of additional liquid to be introduced into the preparation tank depending on the detected density and / or viscosity value of the glaze in order to obtain a reference density and / or viscosity value.

[0046] Preferably, the first conduit and the second conduit are in communication with each other, and a third valve member is provided therebetween, the third valve member being operable to selectively allow one of the glaze or the additional liquid to enter the hollow body.

[0047] Preferably, the third valve member is operably connected to an electronic unit configured to activate the third valve member itself when the calculated density and / or viscosity value or the updated density and / or viscosity value is different from the reference density and / or viscosity value so as to only allow additional liquid to be delivered to the hollow body.

[0048] Preferably, the second valve member is arranged upstream of the third valve member with respect to the flow direction of the glaze from the preparation tank towards the hollow body.

[0049] Preferably, a sensor of the level of the glaze contained in the preparation tank is provided, the sensor being adapted to send a signal to an electronic unit adapted to calculate a corresponding volume signal.

[0050] Preferably, the sensor is adapted to send a signal to the electronic unit before the introduction of additional liquid into the preparation tank and at the end of the introduction.

[0051] Preferably, the apparatus comprises at least one collecting tank for the glaze to be introduced into the preparation tank, a conveying member for conveying the glaze from the collecting tank to the preparation tank, the preparation tank comprising a screening member for screening the glaze, and at least one recycling tank suitable for collecting the glaze dispensed from the glaze dispensing device and hydraulically connected to the collecting tank by means of a recycling conduit.

[0052] Preferably, a method for decorating a ceramic article according to the invention comprises at least the following stages: preparing a glaze to be applied to the ceramic article to be decorated, and applying the prepared glaze to the ceramic article itself.

[0053] Preferably, the preparation stage includes at least the following stages:

[0054] Introduce the glaze into the preparation pot;

[0055] Check the glaze level in the preparation tank;

[0056] Calculate the glaze volume corresponding to the detection level;

[0057] measuring the density and / or viscosity of the glaze contained in the preparation tank to identify a detected density and / or viscosity value;

[0058] The detected density and / or viscosity value is compared with the reference density and / or viscosity value and, if different, the amount of additional liquid with a predetermined density and / or viscosity to be introduced into the preparation tank is calculated depending on the calculated volume to obtain the reference density and / or viscosity value.

[0059] A method for decorating ceramic articles comprises at least the following stages:

[0060] - preparing a glaze to be applied to the ceramic article to be decorated;

[0061] - applying the prepared glaze to the ceramic article;

[0062] The preparation stage includes at least the following stages:

[0063] - Introducing the glaze into the preparation tank 8;

[0064] - Check the glaze level in the preparation tank 8;

[0065] - Calculate the glaze volume corresponding to the detection level;

[0066] - measuring the density and / or viscosity of the glaze contained in the preparation tank in order to identify the detected density and / or viscosity value D C ;

[0067] The density and / or viscosity value D will be detected C With reference density and / or viscosity value D RThe comparison is performed and, if different, the amount of additional liquid with a predetermined density and / or viscosity to be introduced into the preparation tank 8 is calculated depending on the calculated volume to obtain a reference density and / or viscosity value D R . BRIEF DESCRIPTION OF THE DRAWINGS

[0068] Other characteristics and advantages of the invention will become more apparent from the description of a preferred but not exclusive embodiment of a device for decorating ceramic articles, illustrated by way of indicative but not limiting example in the accompanying drawings, in which:

[0069] Figure 1 is a schematic diagram of an apparatus according to the present invention;

[0070] Figure 2 It is used to measure Figure 1 Schematic diagram of the device for the measurement of density and / or viscosity. DETAILED DESCRIPTION

[0071] With particular reference to these drawings, reference numeral 1 indicates globally a device for decorating ceramic articles.

[0072] The installation 1 comprises at least one machine 2 for decorating ceramic articles, comprising a surface (not shown in the figures) for conveying the ceramic articles and at least one glaze distributing device 4 for distributing glaze on the ceramic articles.

[0073] According to the invention, the machine 2 comprises at least one internal reservoir 5 suitable for containing the glaze S to be applied to the ceramic article and hydraulically connected to the glaze dispensing device 4 .

[0074] Still according to the invention, the device 1 comprises at least one preparation tank 8 of glaze S, hydraulically connected to the internal reservoir 5 by means of transfer members 7, 9 of the glaze S. The preparation tank 8 is provided with at least one measuring device 10 for measuring the density and / or viscosity of the glaze S contained in the preparation tank itself.

[0075] In particular, the supply tank 6 and the preparation tank 8 are arranged outside the machine 2 .

[0076] The device 1 then comprises at least one electronic processing and control unit 11 operatively connected to at least the measuring means 10 in order to identify the detected density and / or viscosity value D of the glaze. C , and connected at least to the transfer members 7, 9, the electronic unit 11 is suitable for detecting the density and / or viscosity D C Corresponds to reference density and / or viscosity value D R When the command is sent, the glaze is sent from the preparation tank 8 to the internal reservoir 5.

[0077] Depending on the embodiment, the electronic unit 11 may thus be adapted to receive from the measuring device 10 data corresponding to the detected density and / or viscosity D C or, as in the embodiments described below, itself may be suitable for calculating a density and / or viscosity value D C .

[0078] Advantageously, the device 1 comprises at least one supply tank 6, which is located between the preparation tank 8 and the internal reservoir 5 and is hydraulically connected thereto. The transfer members 7, 9 in turn comprise a first transfer member 7 for transferring the glaze S from the supply tank 6 to the internal reservoir 5 and a second transfer member 9 for transferring the glaze S from the preparation tank 8 to the supply tank 6. In particular, the electronic unit 11 is adapted to detect the density and / or viscosity D C Corresponds to reference density and / or viscosity D R The glaze S is sent from the preparation tank 8 to the supply tank 6.

[0079] Suitable stirring means are arranged within the supply tank 6, the stirring means being adapted to move the glaze contained therein.

[0080] Preferably, the internal reservoir 5 comprises acquisition means 12, for example of the optical type, for acquiring the level of the glaze S therein. The electronic unit 11 is operatively connected to the acquisition means 12 and to the first transfer means 7. The electronic unit 11 is programmed to command the first transfer means 7 to send an amount of glaze S from the supply tank 6 to the internal reservoir 5, which is proportional to the drop in the glaze level detected by the acquisition means 12 relative to a predetermined maximum level.

[0081] In more detail, the first transfer member 7 comprises at least one conveying channel 13 for the glaze, along which is arranged a first pumping member 14, for example of the peristaltic pump type. The electronic unit 11 is then programmed to command the first pumping member 14 so that the greater the distance of the glaze level detected by the acquisition member 12 relative to a predetermined maximum level, the greater the amount of glaze sent towards the internal reservoir 5, and vice versa.

[0082] Advantageously, the machine 2 also comprises a pressurizing member 15 suitable for maintaining the pressure inside the internal reservoir 5 substantially equal to a predetermined value.

[0083] In more detail, the pressurizing member 15 includes at least a pressurizing channel 15a, which is connected to the internal reservoir 5 and can be connected to the pressurized air source G, and a valve member 15b, which is arranged along the pressurizing channel 15a and is suitable for preventing air from passing from the internal reservoir 5 to the pressurized air source and discharging air to the outside when the pressure in the internal reservoir 5 exceeds a predetermined limit value.

[0084] The pressurizing member 15 and the first pumping member 14 work independently of each other and in conjunction with each other to maintain the pressure in the internal reservoir 5 substantially constant (ie except for fluctuations due to varying glaze levels therein and tolerances of the components used).

[0085] In the preferred embodiment shown in the figures, the glaze dispensing device 4 comprises at least one internal hollow container 16 for collecting the glaze S to be applied to the ceramic object, wherein the container 16 is provided with at least one set of through holes (not shown in detail in the figures) for the glaze to flow out and at least one drum (not shown in detail in the figures) arranged in the container 16 and rotatable around a relative axis. The drum is provided with at least one set of protrusions suitable for opening and closing these holes in a sequential and cyclical manner during the rotation of the drum itself, so as to allow and prevent the glaze to flow out of the container 16, respectively. The volume located between the inner wall of the container 16 of elongated configuration and the drum defines a glaze receiving chamber 17, which is hydraulically connected to the internal reservoir 5 by means of a supply circuit 18 of the glaze S.

[0086] Preferably, the supply circuit 18 includes at least one supply section 18a communicating with the internal reservoir 5 , at least one pair of glaze transfer sections 18b communicating with two mutually opposite axial ends of the accommodating chamber 17 , and at least one return section 18c communicating with the supply tank 6 .

[0087] The supply circuit 18 then comprises a first valve member 19 between each of the transfer sections 18b, the supply section 18a and the return section 18c, which is operable to selectively place each of the transfer sections 18b in communication with the internal reservoir 5 and the supply tank 6. The first valve member 19 is, for example, a valve member of the three-way solenoid valve type.

[0088] Suitably, the electronic unit 11 is operatively connected to the first valve members 19 and is programmed to activate one of the first valve members 19 at predetermined time intervals so as to place the supply section 18a in communication with the associated transfer section 18b, and to activate the other of the first valve members 19 so as to place the associated transfer section 18b in communication with the return section 18c. In this way, the glaze contained in the internal reservoir 5 enters the receiving chamber 17, in which one of its axial ends is located, and flows out from the opposite end, taking with it any bubbles and transferring them to the interior of the supply tank 6.

[0089] This operation is usually carried out during the filling phase of the initially empty receiving chamber 17 and during any production gaps.

[0090] Advantageously, the supply tank 6 comprises sensor means (not shown in detail) adapted to detect the glaze level therein. The electronic unit 11 is operatively connected to these sensor means and is configured to detect when the glaze level in the supply tank 6 reaches a predetermined minimum value L MIN When and at the same time when preparing the density and / or viscosity D of the glaze in the tank 8 C Essentially equal to the reference density and / or viscosity D R (ie, within a predetermined range), the second transfer member 9 is commanded to be activated.

[0091] In more detail, the second transfer member 9 comprises at least one glaze transfer duct 20 and a second pumping member 21 arranged along the transfer duct itself and operatively connected to the electronic unit 11 .

[0092] Similarly, the electronic unit 11 is configured to activate the glaze supply when the glaze in the supply tank 6 reaches a predetermined maximum level L MAX The sending of the glaze by means of the second transfer member 9 is stopped when the predetermined maximum level L is identified. MAX , so that in the case of recycling, the glaze contained in the internal reservoir 5 can also be conveyed in the supply tank 6.

[0093] Furthermore, the supply tank 6 and the preparation tank 8 are hydraulically connected to each other by means of a recirculation channel 22, along which at least one solenoid valve 23 is arranged operatively connected to the electronic unit 11. Specifically, the electronic unit 11 operates the solenoid valve 23 to allow the glaze contained in the supply tank 6 to recirculate inside the preparation tank 8.

[0094] Advantageously, the measuring device 10 comprises at least one hollow body 24 defining a containing compartment 25 provided with at least one inlet port 26 and at least one outlet port 27 for the glaze S, wherein the outlet port 27 has a smaller conveying cross-section than the inlet port 26 and is arranged on the top of the preparation tank 8 so as to discharge the glaze therein.

[0095] The measuring device 10 then comprises a weighing member 28 associated with the hollow body 24 and a detection member 29 for detecting the glaze level inside the containing compartment 25 , wherein the electronic unit 11 is operatively connected to the weighing member 28 and the detection member 29 .

[0096] More specifically, the detection member 29 is suitable for sending at least a first signal related to the weight of the hollow body 24 to the electronic unit 11 when the glaze contained in the containing compartment 25 reaches a first predetermined level L1, and sending at least a second signal related to the weight of the hollow body 24 when the glaze reaches a second predetermined level L2 lower than the first predetermined level L1.

[0097] The electronic unit 11 is configured to calculate a frit weight value corresponding to the difference between the first signal and the second signal and calculate the density of the frit depending on the calculated weight value and the volume of the accommodation compartment 25 between the first level L1 and the second level L2.

[0098] Furthermore, the electronic unit 11 comprises at least one programmable memory 30 having a volume value of the accommodation compartment 25 situated at least between the first level L1 and the second level L2 .

[0099] The measuring device 10 also comprises at least one timer 31 associated with the electronic unit 11 configured to calculate the time interval elapsed between the emission of the first signal and the emission of the second signal and to calculate the glaze viscosity identification value depending on the calculated time interval.

[0100] For this purpose, the hollow body 24 comprises a Ford cup 32 which defines the outlet port 27 and which is therefore arranged below the first and second predetermined levels L2 .

[0101] Preferably, the Ford cup 32 is a Type 4 Ford cup.

[0102] Specifically, the electronic unit 11 calculates the glaze viscosity identification value depending on the time interval that has passed between the transmission of the first signal and the transmission of the second signal.

[0103] In more detail, the electronic unit 11 processes the time interval between sending the first signal and sending the second signal depending on the volume inserted between the first level L1 and the second level L2, and compares the time interval thus processed with a preset reference time value and uniquely relates the time interval to the corresponding viscosity identification value.

[0104] Suitably, the electronic unit 11 processes the measured time value and compares it with a reference time value, which is coded, for example, based on the time value of the Ford Cup, and identifies a viscosity value for a given density value.

[0105] Therefore, the measured time value is used to identify the viscosity value of the liquid introduced into the hollow body 24 .

[0106] More specifically, the electronic unit 11 processes the measurement time intervals depending on the interpolation between the first level L1 and the second level L2 and the ratio of the preset volume to the reference Ford Cup volume and whose relative time values ​​have been preset for different reference density values.

[0107] At this point it should be noted that the particular means of providing a timer associated with the electronic unit 11 and the Ford cup 32 defining the outlet port 27 allows the electronic unit 11 to measure the glaze viscosity identification value in a simple and intuitive manner.

[0108] Usefully, the receiving compartment 25 comprises at least one drainage gap 33 communicating with the outside and arranged at a higher level than the first level L1 and adapted to allow the glaze to flow out to the outside. The drainage gap 33 thus defines the maximum volume of the glaze received in the receiving compartment 25.

[0109] Suitably, the apparatus 1 comprises a hydraulic circuit 34 for supplying the measuring device 10, wherein the hydraulic circuit 34 comprises a second transfer member 9, a second valve member 35 arranged along the transfer duct 20, a first duct 36 connected to the second valve member 35 and suitable for sending the glaze contained in the preparation tank 8 into the hollow body 24, and at least a second duct 37 suitable for introducing an additional liquid having a predetermined density and / or viscosity into the preparation tank 8.

[0110] Thus, the transfer conduit 20 has a first section 20a communicating with the preparation tank 8 and a second section 20b communicating with the supply tank 6, and a second valve member 35 is located between the first section and the second section, which is in turn connected to the first conduit 36. The second valve member 35 can be activated to selectively send the glaze into the supply tank 6 or along the first conduit 36.

[0111] The programmable memory 30 contains at least one reference density and / or viscosity value D R and the density and / or viscosity value of the additional liquid, and the electronic unit 11 is programmed to refer to the density and / or viscosity value D R With the detection density and / or viscosity value D C For comparison, and when testing density and / or viscosity D C Different from reference density and / or viscosity D R When commanded, additional liquid is introduced into the preparation tank 8.

[0112] More specifically, the electronic unit 11 is programmed to calculate an updated density and / or viscosity value D depending on the amount of additional liquid introduced into the preparation tank 8. A , and when updating the density and / or viscosity value D A Different from the reference density and / or viscosity value D R When commanded, additional liquid is introduced into the preparation tank 8.

[0113] Specifically, the electronic unit 11 is configured to calculate the density and / or viscosity D of the glaze S according to C to calculate the amount of additional liquid to be introduced into the preparation tank 8 to obtain a reference density and / or viscosity value D R .

[0114] Suitably, the electronic unit 11 is operatively connected to the second valve member 35 and is configured to detect the density and / or viscosity value D C Or update density and / or viscosity value DA Corresponds to reference density and / or viscosity value D R They are started at the same time to allow the glaze S to be transported to the supply tank 6.

[0115] In the embodiment shown in the drawings, the first conduit 36 ​​and the second conduit 37 are in communication with each other, and a third valve member 38 is provided therebetween, wherein the third valve member 38 is operable to selectively allow one of the glaze or the additional liquid to enter the hollow body 24 .

[0116] In more detail, the third valve member 38 is operatively connected to the electronic unit 11, which is configured to detect the density and / or viscosity value D C Or update density and / or viscosity value D A Different from the reference density and / or viscosity value D R The third valve member itself is activated at the same time so as to allow only additional liquid to be delivered to the hollow body 24.

[0117] The third valve member 38 is arranged downstream of the second valve member 35 with respect to the flow direction D of the glaze from the preparation tank 8 towards the hollow body 24 .

[0118] On the other hand, the second conduit 37 can be connected to an additional liquid supply source, for example to a water supply main, by means of a fourth valve member 39, which can be operated to selectively set the second conduit 37 to be connected to a supply source of pressurized liquid A or to the outside so as to allow any bubbles therein to be driven out.

[0119] Preferably, the device 1 comprises at least one sensor 40 of the glaze level contained in the preparation tank 8, for example of the optical type, suitable for sending a corresponding signal to the electronic unit 11 adapted to calculate a corresponding volume value.

[0120] In particular, the sensor 40 is adapted to send a signal to the electronic unit 11 before the introduction of the additional liquid into the preparation tank 8 and at the end of the introduction.

[0121] Advantageously, the device 1 comprises at least one collecting tank 41 of the glaze to be introduced into the preparation tank 8 , a transfer member 42 for transferring the glaze from the collecting tank 41 to the preparation tank 8 , the preparation tank comprising a sieving member 43 for sieving the glaze.

[0122] Furthermore, the apparatus 1 comprises at least one recirculation tank 44 suitable for collecting the glaze distributed by the glaze distributing device 4 and hydraulically connected to the collecting tank 41 by means of a recirculation duct 45 .

[0123] The operation of the present invention is as follows.

[0124] Initially, ie before starting the process of decorating the ceramic article, the preparation of the glaze S to be sent to the glaze dispensing device 4 is carried out.

[0125] The glaze contained in the collection tank 41 is then sent to the preparation tank 8 by means of a conveying member 42 that sieves it.

[0126] The glaze contained in the preparation tank 8 is in turn sent to the measuring device 10 for measuring density and viscosity via the hydraulic circuit 34. The electronic unit 11 then calculates the density and / or viscosity of the glaze in the above-described manner until a density and / or viscosity value D is detected. C Or update density and / or viscosity value D A Corresponds to the set reference density and / or viscosity D R .

[0127] At this time, the glaze contained in the preparation tank 8 is sent to the supply tank 6 by means of the second transfer member 9 until it reaches a preset maximum level L MAX .

[0128] The glaze is then sent from the supply tank 6 to the internal reservoir 5 by means of a first transfer member 7 .

[0129] After the internal reservoir 5 is filled, the glaze contained therein is sent to the receiving chamber 17 of the glaze dispensing device 4. Since the receiving chamber 17 is initially empty, the electronic unit 11 provides for the activation of the first valve members 19, so that one of them sets the supply section 18a to communicate with one of the transfer sections 18b, and sets the other of the transfer sections 18b to communicate with the return section 18c. In this way, the glaze is introduced into the receiving chamber 17 through one of its axial ends and leaves through the opposite axial end, thereby taking away the air contained in the receiving chamber 17.

[0130] After the receiving chamber 17 is filled and completely defoamed, the electronic unit 11 activates the first valve members 19 so that they both place the supply section 18a in communication with the associated transfer section 18b so as to simultaneously supply the receiving chamber itself through both ends during operation of the glaze dispensing device 4.

[0131] During the filling phase of the containing chamber 17, the level of glaze contained in the internal reservoir 5 decreases and is detected by the acquisition member 12, which communicates the corresponding reading by sending a signal to the electronic unit 11. The electronic unit 11 in turn commands the first pumping member 14 so as to restore the maximum level in the internal reservoir 5 in the shortest possible time, whereby the greater the distance of the detected glaze level from the predetermined maximum level, the faster the corresponding peristaltic pump runs. At the same time, the pressurizing member 15 is activated to maintain the pressure in the internal reservoir 5 substantially constant by introducing pressurized air or allowing it to be discharged to the outside.

[0132] A similar operation also takes place during the decoration phase, during which the level of glaze contained in the internal reservoir 5 is varied.

[0133] In the event of the occurrence of a production gap detected by the electronic unit 11 , the electronic unit is configured to intervene in the first valve member 19 in a manner similar to that described above, so as to effect the removal of any air pockets contained in the receiving chamber 17 .

[0134] When the level of the glaze contained in the supply tank 6 reaches a predetermined minimum level L MIN When the electronic unit 11 returns the glaze from the preparation tank 8 by operating the second transfer member 9.

[0135] More specifically, only when the density and / or viscosity value D is detected C Or update density and / or viscosity value D A Corresponds to reference density and / or viscosity D R When the density and / or viscosity of the glaze contained in the preparation tank 8 is different from the reference density and / or viscosity D R In this case, the electronic unit 11 operates the third and fourth valve members 38 and 39 to introduce a predetermined amount of additional liquid into the preparation tank 8, while maintaining the second valve member 35 in a state where the first section 20a is set to communicate with the first conduit 36, so as to recirculate the glaze contained in the preparation tank 8 in the hollow body 24 after the additional liquid is introduced into the hollow body.

[0136] In practice, it has been established that the described invention achieves the intended objectives and that, in particular, the device covered by the invention enables the glaze to be prepared in an automatic and reliable manner so that it has the desired rheological properties and is ready for use, thanks to the presence of a plurality of containers separated from one another, namely the preparation tank, the containing chamber and the reservoir inside the machine for decorating articles and the use of measuring devices for measuring the density and / or viscosity.

[0137] Furthermore, the first pumping means and the pressurizing means make it possible to maintain the glaze level and the pressure inside the internal reservoir almost constant, so as to optimize the supply of the glaze itself to the dispensing device.

[0138] It is also noted that the special means of providing an electronic unit comprising at least one programmable memory having a reference density and / or viscosity value D makes it possible to automatically correct the density and / or viscosity of the glaze to a reference value. R , having a value corresponding to the volume of the receiving chamber located between the first predetermined level and the second predetermined level, and having a predetermined density and / or viscosity value of the additional liquid.

[0139] Finally, it is important to emphasize that the particular means of detecting the glaze level in the preparation tank in order to identify the corresponding glaze volume and, depending on the latter figure, to calculate the precise amount of additional liquid to be introduced allow to reach the reference density and / or viscosity values ​​in a single step, i.e. by introducing the additional liquid only once.

[0140] Last but not least, the use of a timer associated with the electronic unit and the Ford cup enables the measurement of the viscosity identification value of the liquid.

Claims

1. A device (1) for decorating ceramic products, comprising: at least one machine (2) for decorating ceramic articles, said machine comprising a surface for conveying the ceramic articles and at least one glaze distributing device (4) for distributing glaze on said ceramic articles; wherein the machine (2) comprises at least one internal reservoir (5) suitable for containing the glaze (S) to be applied to the ceramic article and hydraulically connected to the glaze dispensing device (4), at least one glaze preparation tank (8) hydraulically connected to the internal reservoir (5), wherein the glaze preparation tank (8) is provided with at least one measuring device (10) for measuring the density and / or viscosity of the glaze contained in the preparation tank itself, transfer means (7, 9) are provided for transferring the glaze (S) from the glaze preparation tank (8) to the internal reservoir (5), and at least one electronic unit (11) operatively connected to at least the measuring device (10) in order to identify the detected density and / or viscosity value (D C ) and is operably connected to the transfer member (7, 9), the electronic unit (11) being suitable for detecting density and / or viscosity (D C ) corresponds to the reference density and / or viscosity value (D R ) when commanding the glaze (S) to be sent from the preparation tank (8) to the internal storage (5); Characterized in that the glaze dispensing device (4) comprises at least one internal hollow container (16) for collecting the glaze to be applied to the ceramic article, wherein the container (16) is provided with at least one set of through holes for the glaze to flow out; at least one drum housed in said container (16) and operable to rotate about a relative axis, wherein the volume between the inner wall of the container (16) and the drum defines a receiving chamber (17) for the glaze, the receiving chamber being hydraulically connected to the internal reservoir (5) by means of a supply circuit (18) for the glaze, the orifice protruding inwardly into the receiving chamber (17); And it is characterized in that the drum is provided with at least one set of protrusions suitable for opening and closing the holes in a sequential and cyclical manner during the rotation of the drum itself, so as to respectively allow and prevent the glaze from being released from the container (16).

2. The device (1) according to claim 1, characterized in that The device comprises at least one supply tank (6) for the glaze (S), which is located between the internal reservoir (5) and the preparation tank (8) and is hydraulically connected thereto, and the transfer member (7, 9) comprises a first transfer member (7) for transferring the glaze (S) from the supply tank (6) to the internal reservoir (5) and a second transfer member (9) for transferring the glaze (S) from the preparation tank (8) to the supply tank (6).

3. The device (1) according to claim 1 or 2, characterized in that The internal reservoir (5) comprises acquisition means (12) for acquiring the level of the glaze (S) therein, and the electronic unit (11) is operatively connected to the acquisition means (12) and the first transfer means (7).

4. The device (1) according to claim 3, characterized in that The electronic unit (11) is programmed to command the first transfer member (7) to send an amount of glaze (S) from the supply tank (6) to the internal reservoir (5), the amount being proportional to the drop in the glaze level detected by the acquisition member (12) relative to a predetermined maximum level.

5. Device (1) according to one or more of the preceding claims, characterized in that The machine (2) comprises a pressurizing member (15) suitable for maintaining the pressure in the internal reservoir (5) substantially equal to a predetermined value.

6. Device (1) according to one or more of the preceding claims, characterized in that The supply circuit (18) includes at least one supply section (18a) connected to the internal reservoir (5), at least one pair of glaze transfer sections (18b) connected to two mutually opposite axial ends of the accommodating chamber (17) and at least one return section (18c) connected to the supply tank (6), and the supply circuit includes a first valve member (19), which is located between each transfer section in the transfer sections (18b), the supply section (18a) and the return section (18c) and is operable to selectively set each transfer section in the transfer sections (18b) to be connected to the internal reservoir (5) and the supply tank (6).

7. The device (1) according to claim 6, characterized in that The electronic unit (11) is operably connected to the first valve members (19) and is programmed to activate one of the first valve members (19) within a predetermined time interval so as to set the supply section (18a) to communicate with the associated transfer section (18b), and to activate another of the first valve members (19) so as to set the associated transfer section (18b) to communicate with the return section (18c).

8. Device (1) according to one or more of the preceding claims, characterized in that The supply tank (6) comprises a sensor member adapted to detect the glaze level therein, and the electronic unit (11) is operatively connected to the sensor member and is programmed to detect when the glaze level in the supply tank (6) reaches a predetermined minimum value (L MIN ) and the detected density and / or viscosity (D C ) is equal to the reference density and / or viscosity (D R ) when a command is given to start the second transfer member (9).

9. Device (1) according to one or more of the preceding claims, characterized in that The measuring device (10) comprises - at least one hollow body (24) defining a glaze containing compartment (25) comprising: o at least one inlet port (26) and at least one outlet port (27) for the glaze, wherein the outlet port (27) has a smaller conveying cross section than the inlet port (26) and is arranged on the top of the preparation tank (8) in order to discharge the glaze therein; - a weighing member (28) associated with the hollow body (24); - detection means (29) for detecting the glaze level in the containing compartment (25); - wherein the electronic unit (11) is operatively connected to the weighing member (28) and the detection member (29), the latter being adapted to send to the electronic unit (11) at least a first signal related to the weight of the hollow body (24) when the glaze contained in the containing compartment (25) reaches a first predetermined level (L1), and to send at least a second signal related to the weight of the hollow body (24) when the glaze reaches a second predetermined level (L2) below the first predetermined level (L1), the electronic unit (11) being configured to calculate a glaze weight value corresponding to the difference between the first signal and the second signal, and to calculate the density of the glaze depending on the calculated weight value and the volume of the containing compartment (25) between the first predetermined level (L1) and the second predetermined level (L2); and wherein the electronic unit (11) comprises at least one programmable memory (30) having a volume value of the containing compartment (25) at least between the first predetermined level (L1) and the second predetermined level (L2); - at least one timer (31) associated with said electronic unit (11) configured to calculate said time interval elapsed between the sending of said first signal and the sending of said second signal and to calculate a glaze viscosity identification value as a function of said calculated time interval.

10. The device (1) according to claim 9, characterized in that The second transfer member (9) comprises at least one transfer conduit (20) and a second pumping member (21) arranged along the transfer conduit (20), and the device comprises at least one hydraulic circuit (34) comprising: - the second transfer member (9); a second valve member (35) arranged along the transfer duct (20) and actuated to selectively send the glaze to the supply tank (6) or to a first duct (36) suitable for sending the glaze contained in the preparation tank (8) into the hollow body (24); - at least one second conduit (37) suitable for introducing an additional liquid having a predetermined density and / or viscosity into the preparation tank (8); The programmable memory (30) contains at least one reference density and / or viscosity value (D R ) and the density and / or viscosity value of the additional liquid, and the electronic unit (11) is programmed to convert the reference density and / or viscosity value (D R ) and the detected density and / or viscosity (D C ) are compared, and when the detected density and / or viscosity (D C ) is different from the reference density and / or viscosity (D R ) when commanding the additional liquid to be introduced into the preparation tank (8).

11. The device (1) according to claim 10, characterized in that The electronic unit (11) is programmed to calculate an updated density and / or viscosity value (D A ), and when the updated density and / or viscosity value (D A ) is different from the reference density and / or viscosity value (D R ) when commanding the additional liquid to be introduced into the preparation tank (8).

12. The device (1) according to claim 11, characterized in that The second valve member (35) is operatively connected to the electronic unit (11), which is configured to detect the density and / or viscosity value (D C ) or the updated density and / or viscosity value (D A ) corresponds to the reference density and / or viscosity value (D R ) when the second valve member itself is activated to allow the glaze (S) to be transported to the supply tank (6).

13. Device (1) according to one or more of claims 10 to 12, characterized in that The electronic unit (11) is configured to determine the detected density and / or viscosity value (D C ) to calculate the amount of the additional liquid to be introduced into the preparation tank (8) to obtain the reference density and / or viscosity value (D R ).

14. Device (1) according to one or more of claims 10 to 13, characterized in that The first conduit (36) and the second conduit (37) are in communication with each other and include a third valve member (38) therebetween, the third valve member being operable to selectively allow one of the glaze (S) or the additional liquid to enter the hollow body (24).

15. The device (1) according to claim 14, characterized in that The third valve member (38) is operatively connected to the electronic unit (11), which is configured to detect the density and / or viscosity value (D C ) or the updated density and / or viscosity value (D A ) is different from the reference density and / or viscosity value (D R ) when the third valve member itself is activated so as to allow only the additional liquid to be delivered to the hollow body (24).

16. Device (1) according to one or more of claims 10 to 15, characterized in that The second valve member (35) is arranged upstream of the third valve member (38) with respect to a flow direction (D) of the glaze (S) from the preparation tank (8) toward the hollow body (24).

17. Device (1) according to one or more of the preceding claims, characterized in that The device comprises at least one sensor (40) of the level of glaze (S) contained in the preparation tank (8), the sensor being suitable for sending a signal to the electronic unit (11) adapted to calculate a corresponding volume value.

18. The device (1) according to claim 17, characterized in that The sensor (40) is suitable for sending a signal to the electronic unit (11) before the introduction of the additional liquid into the preparation tank (8) and at the end of the introduction.

19. Device (1) according to one or more of the preceding claims, characterized in that The device comprises at least one collecting tank (41) for the glaze to be introduced into the preparation tank (8), a conveying member (42) for conveying the glaze from the collecting tank (41) to the preparation tank (8), the preparation tank comprising a screening member (43) for screening the glaze, and is characterized in that the device comprises at least one recycling tank (44), which is suitable for collecting the glaze distributed from the glaze distribution device (4) and is hydraulically connected to the collecting tank (41) by means of a recycling conduit (45).

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