EP4151984A1

EP4151984A1 - Improved control apparatus for a spraying plant

Info

Publication number: EP4151984A1
Application number: EP22196804.3A
Authority: EP
Inventors: Bruno Burato; Cesare DAL MONTE; Mirco Masetta
Original assignee: GER Elettronica Srl
Current assignee: GER Elettronica Srl
Priority date: 2021-09-21
Filing date: 2022-09-21
Publication date: 2023-03-22
Also published as: IT202100024266A1

Abstract

Improved control apparatus (1) for a plant (100) or a spraying device, said plant (100) or device comprising at least one spray gun (14) configured to spray a treatment liquid on at least one product (8) to be treated by generating a corresponding spray pattern (22), said apparatus comprises:
- at least one light source (30) arranged to face towards said spray pattern (22) and configured to generate at least one electromagnetic radiation beam (32) directed to cross said spray pattern (22) thus defining an intersection zone (31);
- at least one image sensor (24) arranged to face towards said intersection zone (31) of said spray pattern (22) and configured to acquire at least an image of said intersection zone (31) of said spray pattern (22),
- a processing unit in data link with said image sensor (24) which receives said at least one image captured by said at least one image sensor (24), said processing unit being configured to process the image (24) thus received, preferably so as to calculate and / or define the characteristics and / or the quality of said spray pattern (22) and / or to send the received and / or processed image to a display device in which it is presented to the operator;
characterized by the fact that said laser beam generated by said light source (30) comprises a first wavelength and by the fact that said image sensor (24) comprises at least one optical filter adapted to prevent the detection of electromagnetic radiation comprising second wavelength different from said first wavelength of said laser beam.

Description

The present invention relates to an improved control apparatus for a spraying plant or device on manufactured articles, in particular on hides and the like.
Therefore, the present invention finds advantageous use in the technical sector of the production and processing of manufactured articles, in particular manufactured articles made with hides and the like.
In the industry for the processing of manufactured articles, and in particular in the hide processing sector, it is known to undergo the surface of the hides themselves, coming from previous treatment phases, to spraying with a nebulized liquid, generally a pigment, which gives the background color of the hide itself, or a paint or a fixative. For this purpose it is provided that the hides to be treated are made to advance on a traditional conveyor belt and that a handling structure placed above the belt and equipped with a plurality of spray guns, sends a nebulized jet of liquid on their upper surface..
Since the irregular shape of the hides, as well as their considerable dimensions (even of 8m²) mean that they do not transversely cover the entire area of the belt in which the guns are enabled to spray and since the hides are spaced longitudinally from each other on the belt, the various guns are often found above portions of the belt not covered by the hide and, if they sprayed the nebulized liquid continuously, they would inevitably waste it and would also lead to an increase in maintenance for cleaning the belt. transport and disposal of the removed product.
To counter this, the system generally comprises a unit for detecting the shape of the hide and a unit (called "economizer") for processing the detected shape, as well as the movement of the hide on the belt, in order to properly control the activation of the spray guns.
In this way, therefore, each gun is activated so as to spray the nebulized liquid only when a hide passes under it. However, since there is an inevitable delay in activating the gun, it is necessary to anticipate the activation command with respect to the instant in which the gun, which is in motion, begins to pass over the hide, which is also in motion but according to a different direction. Of course the same must happen when the gun leaves the hide.
A first difficulty linked to this expedient consists in the fact that the switching time of a spray gun is not fixed but varies according to the control pressure of the gun itself, the characteristics of the pneumatic system, the characteristics of the solenoid valve that controls the pistol, the characteristics of the pistol and the state of clogging and work wear of this one.
Practice has led to the need to measure, by means of photocells or equivalent sensors, the switching time of the guns in order to be able to compensate it precisely. However, this has resulted in a difficulty in calibrating the device, as it has required to reliably detect the presence of the spray pattern created by each gun at the instant in which it is formed, in order to determine the lead time, with which the relative command must be given. In fact, this detection of the presence of the spray pattern is somewhat laborious due to the need to correctly position the photocells or sensors, which are not always reliable, especially in the presence of spray patterns formed by clear or transparent pigments.
Another drawback consists in the fact that this calibration must be repeated periodically due to the inevitable alterations in the functioning of the apparatus due to both wear and fouling of the guns, which over time modify their functional characteristics. Furthermore, this periodic calibration of the apparatus requires manual interventions of a certain laboriousness, linked to the need to periodically apply and remove the various photocells or, if they are permanently installed, to the need to cover them and uncover them periodically to make only the relative ones active. to the gun under calibration.
Both VE2001A000093 and VE2011A000060 have already proposed solutions to improve this type of equipment; in particular, VE2011A000060 proposed to use, for the calibration phase of the apparatus, the electric signal corresponding to the pressure variation that occurs in the compressed air circuit which feeds the guns when a spraying command is given.
However, despite these improvement solutions, traditional spraying systems are not completely without drawbacks, both in terms of the quality of the final result and in terms of waste elimination.
In particular, the quality of the result of the sprayed hide depends directly on the good functioning of the system in general, and above all on the functioning of the spray guns, which are particularly subject to malfunctions caused by dirt, wear and adjustment problems.
In this regard, it should be considered that the malfunctioning of one or more guns of the system involves defects on the hides, such as unsightly scratches along the trajectories of the guns, and ultimately this involves an important economic damage given that the result obtained, not being completely satisfactory, it requires repeating the spraying phase again. This in turn involves additional costs and a lowering of the productivity level of the plant, without considering that in some cases the quality of the final result is in any case definitely compromised.
In particular, the malfunction of the gun occurs when, by spraying the product using the gun itself, the spray pattern obtained deviates, beyond a tolerance decided by the user, from the ideal and known pattern, with a slightly flattened conical shape (i.e. with elliptical section), which would be obtained if the gun and the system worked correctly.
At present, the operator detects a possible malfunction by visually assessing the deposit of the product and, once this malfunction has been identified, he must identify the gun or guns that are not working correctly.
It is clear that this operation is not very easy, also considering that the hides to be checked are of considerable size, that the process cannot be slowed down or stopped frequently and that the guns move at particularly high peripheral speeds, of the order of 3 - 4m / s, and that the carousel rotates at about 15 rpm.
It is known in spraying systems, in particular on hides and the like, to implement an apparatus for controlling the regular operation of the spray guns by installing at least one camera that detects the shape of the spray pattern, where it is suitably illuminated in the field of camera reading.
However, the control of the known type of spray pattern has shown application limits, having to adapt the control apparatus to spray booths of the various booth manufacturers. The adaptations refer in particular to the lighting already present in the booth and to the light reflections that may be present and therefore detected by the camera, to the correct lighting of the spray pattern and to the background, downstream of the spray pattern, that the camera sees.
A further drawback of the known type control apparatus for checking the correct operation of the spray gun lies in the fact that it has to cope with the interference of reading by the camera due to the presence of rebound vortices of the sprayed product, which are formed inside the spray booth.
In fact, dynamic vortices are formed inside the spray booths due to the kinetic energy of the treatment liquid emitted by the spray gun, in which these vortices change as the booth varies, for example for a different manufacturer.
Such vortices of treatment liquid can cover or flank the spray pattern, or they can overlap the background which is optimal for reading by the camera, affecting the quality of the camera detection and the reliability of the known type of control apparatus.
The object of the invention is to provide an improved control apparatus for a spraying system which allows the correct operation of at least one spraying gun to be monitored quickly and easily.
A further object of the invention is to provide an apparatus which allows to detect the shape of the spray pattern in a safe and reliable manner.
A further object of the invention is to provide an apparatus which can be applied to different types of spray systems or devices already present on the market, in particular to various spray booths already present on the market.
A further object of the invention is to provide an apparatus which allows to monitor the correct operation of at least one spray gun during its operation.
A further object of the invention is to provide an apparatus which supports and facilitates the control activity carried out by the operator both at the time of the initial calibration of the spraying system itself, as well as preferably during the normal operating operation of the latter.
A further object of the invention is that of realizing an apparatus which allows to make it easy to identify any malfunctions of at least one spray gun.
Another object of the invention is to provide an apparatus which automatically warns the operator of the presence of any malfunctions of the system itself, in order to allow manual intervention by the operator himself.
Another object of the invention is to provide an apparatus which allows to automatically correct any malfunctions of the spraying system itself.
Another object of the invention is to provide an apparatus that provides the operator, as well as the customer for whom the hide is intended, a certification of the spraying carried out by the plant itself.
Another object of the invention is to provide an apparatus which provides the operator with useful indications for planning preventive maintenance interventions on the spraying system itself.
Another object of the invention is to provide a reliable apparatus which avoids situations of slowdowns or blocks of the same.
Another object of the invention is to provide an apparatus that allows the operator to identify any guns that may not be working correctly.
Another object of the invention is to provide an apparatus which is constructively and functionally completely reliable.
Another object of the invention is to propose a method for controlling the functionality of the spray guns which can be easily implemented also in already existing spraying systems for hides.
All these objects and others that will result from the following description are achieved, according to the invention, with an apparatus as defined in claim 1 and with a method as defined in claim 10.
The present invention is further clarified hereinafter in some of its favorites. practical embodiment with reference to the attached drawings, in which:

Figure 1: schematically shows a side view of a control apparatus applied to a plant or a spraying device according to the invention, in a first embodiment thereof,
Figure 2: schematically shows a top plan view of the control apparatus of figure 1,
Figure 3: schematically shows a side view of the control apparatus according to the invention, in a second embodiment thereof;
Figure 4: schematically shows a top plan view of the control apparatus of figure 3;
Figure 5: schematically shows a side view of the control apparatus according to the invention, in a third embodiment thereof;
Figure 6: schematically shows a top plan view of the control apparatus of figure 5,
Figure 7: schematically shows a side view of the control apparatus according to the invention, in a fourth embodiment thereof;
Figure 8: schematically shows a top plan view of the control apparatus of figure 7,
Figure 9: schematically shows a side view of the control apparatus according to the invention, in a fifth embodiment thereof;
Figure 10: schematically shows a top plan view of the control apparatus of figure 9;
Figure 11: schematically shows a side view of the control apparatus according to the invention, in a sixth embodiment thereof;
Figure 12: schematically shows a top plan view of the control apparatus of figure 11;
Figure 13: shows a photographic representation of an image acquired by an image sensor of the apparatus according to the invention;
Figure 14: shows a further photographic representation of an image acquired by an image sensor of the apparatus according to the invention.

As can be seen from the figures, the system (or device) for spraying 100 on manufactured articles, in particular hide or similar, on which the control apparatus according to the invention is applicable, is of the per se known type comprising a platform 2 provided with at least one conveyor belt 4, preferably of the type with parallel threads, on which a plurality of articles 6 are placed manually or by an upstream apparatus, not shown, to be subjected to a liquid spraying treatment, in particular a pigment.
The system 100 or device comprises at least one spraying gun 14 configured to spray a treatment liquid on at least one product 8 to be treated, generating a corresponding spray pattern 22.
The term "spray pattern" shall be understood in the following and according to the present patent the jet of nebulized liquid formed by the spray gun, which is formed between the gun itself and the product to be treated. This jet of liquid expands from the spray gun towards the product.
Advantageously, when at least a portion of the conveyor belt 4 is intercepted, a spray booth 101 is placed inside which the at least one spray gun 14 is advantageously arranged.
The apparatus according to the invention comprises at least one light source 30 arranged to be directed towards said spray pattern 22 and generate at least one electromagnetic radiation beam 32 directed to cross said spray pattern 22 thus defining an intersection zone 31.
The apparatus according to the invention further comprises at least one image sensor 24 arranged to face towards said intersection zone 31 of said spray pattern 22 and obtain at least an image of said intersection zone 31 of said spray pattern 22.
Furthermore, the apparatus object of the present invention comprises a processing unit link with said image sensor 24 to allow data transmission which receives said at least one image captured by said at least one image sensor 24 and sends it to a display device in which it is presented to the operator.
In this way, the apparatus object of the present invention allows the operator to quickly and easily view the quality of the spray pattern simply by observing the display device, which may advantageously comprise a monitor or the like.
Furthermore, the apparatus according to the invention allows to continuously monitor the spatial distribution of the spray pattern 22, since the detection by the image sensor 24 and the display on the display device is continuous over time, preferably during the duration of the treatment of the article 8.
Advantageously, said processing unit can be an external computer or a processor integrated in the cameras. Preferably, the processing unit is connected to the control and processing unit (economizer) of the spray guns 14 and / or both units are implemented within the same processor.
Advantageously, moreover, said processing unit being configured to receive a signal containing operating parameters of said spray gun and to associate said signal with said image acquired by said image sensor and preferably to send a corresponding signal to said command and control unit to automatically control the variation of operating parameters of the spray gun 14, as described in more detail below.
For example, the spraying parameters that can be varied by the command and control unit may be the anticipation times for switching the gun between an open state (in which it delivers the treatment liquid) and a closed state (in which it does not deliver the treatment liquid), and / or the pressure of the treatment liquid and / or the pressure of an air flow rate for the nebulization of the treatment liquid.
Preferably, the processing unit is in data communication with the control and processing unit (economizer) of the spray guns 14. More in detail, the processing unit is connected to the control and processing unit by means of at least one cable or via a wireless connection, per se known to those skilled in the art and therefore not described in detail below. Conveniently, the processing unit and the control unit are in data communication to send and / or receive at least synchronization signals for the activation and / or deactivation of the spray gun(s) 14.
Preferably, the control and processing unit is configured to detect, in particular constantly, the position of each spray gun 14.
Preferably, the control and processing unit is configured to detect the activation status of each spray gun 14, ie whether in an open state (in which it dispenses the spray pattern), in a closed state (in which it does not dispense any liquid) or in a semi-open state.
Preferably, the control and processing unit is configured to detect the working state, for example if in a production, washing or test state.
The display device, which can be for example constituted by a screen connected to the processing unit, has the function of displaying the images acquired by means of the sensor 24 and / or the data obtained by the software, described below, loaded and executed in the unit processing itself. Preferably, but not necessarily, the images acquired by the sensor 24 are displayed in real time on the display device.
In this way, therefore, the operator, observing on the display device the images acquired by the sensor 24, is able to evaluate the functionality and characteristics, and therefore the correctness, of the spraying patterns 22. Advantageously, said electromagnetic radiation beam 32 has a substantially planar shape and illuminates at least a cross section of said spray pattern 22 in correspondence with said intersection zone 31.
More in detail, said light source 30 is a laser source suitable for generating a substantially planar laser beam which defines said cross section of said spray pattern 22 at said intersection zone 31.
Preferably, the light source 30 is adapted to generate a laser beam having a wavelength of approximately 660nm.
Advantageously, the high luminous intensity of the laser light allows to minimize the ambient light and the reflections of the artificial lighting inside the spray booth 101 acquired by the image sensor 24.
More clearly, the laser beam crosses the spray pattern 22 and illuminates suspended particles pushed by the spray gun as it passes through. In this way, the image sensor 32, facing the intersection zone 31 of the spray pattern 22, detects these particles illuminated by the laser beam, which define the aforementioned cross-section, thus allowing the operator to quickly and easily see the spatial distribution of the liquid particles that make up the spray pattern 22 on the perimeter.
Advantageously, in order to better illuminate at least perimeter and, preferably, also the internal section of the spray pattern 22, the apparatus according to the invention can comprise two light sources 30 preferably opposite to the spray gun 14. Conveniently, the light sources 30 are configured to generate respective laser beams to illuminate different areas of the spray pattern 22 generated by the spray gun 14.
An example of an image represented on the display device is shown in photographic representations of the attached figures 13 and 14. In these photographic representations the spray gun 14 (arranged above in the photographic representation) and a cross section (visible in white) of the spray pattern 22 are clearly visible.
Advantageously, said laser beam generated by a light source 30 comprises a first wavelength and by the fact that said image sensor 24 comprises at least one optical filter adapted to prevent the detection of electromagnetic radiations having a second wavelength different from said first wavelength of said laser beam.
For example, the optical filter can be made by means of a non-linear optical crystal, (such as for example LBO or the like) which is substantially transparent with respect to a given wavelength while it absorbs other wavelengths, preventing their crossing.
For example, the first wavelength of the electromagnetic radiations that make up the laser beam can be a wavelength in the infrared or ultraviolet range, ie in a suitably invisible spectrum of electromagnetic radiations. Similarly, the image sensor can be suitably configured to capture images generated by electromagnetic radiation in the infrared and / or ultraviolet spectrum, in order to capture the images generated by the laser beam of the light source 30.
In this way, the optical filter of the image sensor 24 can be advantageously configured to block the crossing of electromagnetic radiations in the visible spectrum of electromagnetic radiations, so as to obviate the risk of capturing images including reflections or glows inside the spray booth 101.
Conveniently, into the embodiments illustrated in the attached figures, the control apparatus 1 according to the present invention is configured to be arranged externally with respect to a spray booth 101 in which said spray gun 14 is housed.
According to further embodiments not shown in the figure, at least one of the light source 30 and the image sensor 24 can be configured to be housed inside the spray booth 101.
Otherwise, at least one of the light source 30 and the image sensor 24 can be configured to be housed inside a suitable box-like structure, which can be advantageously housed inside or outside the spray booth 101.
Advantageously, the non-linear optical means can be mechanically associated with the box-like structure for containing the light source 30 and / or of the image sensor 24.
In this way, the apparatus 1 according to the invention obviates the risk of getting dirty with the liquid emitted by the spray guns present inside the spray booth 101.
Furthermore, in this way, the apparatus according to the invention it can be easily installed in systems (or devices) 100 already present on the market, simply by associating it operatively to the spray booth 101 present therein.
Advantageously, the spray booth comprises a substantially box-like containment structure 102 inside which the at least one spray gun 14 is housed and in which the conveyor belt 4 is moved.
Preferably, the containment structure 102 is configured to separate the environment inside the spray booth 101 with respect to the outside environment.
Conveniently, in order to allow the electromagnetic radiation beam 32 generated by the light source 30 to pass through the containment structure 102 of the spray booth 101, and in the same way to allow the image sensor 24 to capture images of the spray pattern 22 ( which is made inside the spray booth 101) the containment structure 102 is at least partially transparent or, at least, is suitably equipped with at least partially transparent windows, in particular with respect to the first wavelength of the laser beam of the light source 30.
In accordance with a first embodiment of the present invention, illustrated in the attached figures 1 and 2, the light source 30 and the image sensor 24 are both arranged facing the same wall of the containment structure 102, preferably a side wall, in which both face the spray pattern 22 inside the spray booth 101 and preferably the light source 30 is arranged above and angled with respect to the image sensor 24.
In accordance with a second embodiment of the present invention, illustrated in the attached figures 3 and 4, the light source 30 and the image sensor 24 are, also in this case, both arranged facing the same wall of the containment structure 102, preferably a side wall, in which both are facing the spray pattern 22 inside the spray booth 101 and preferably the light source 30 is arranged below and angled with respect to the image sensor 24.
In accordance with a third embodiment of the present invention, illustrated in the attached figures 5 and 6, the light source 30 and the image sensor 24 are arranged facing two distinct walls of the spray booth 101. In accordance with this third embodiment, the light source 30 faces an upper wall of the spray booth and the image sensor 24 faces a side wall of the spray booth itself.
In accordance with a fourth embodiment of the present invention, illustrated in the attached figures 7 and 8, the light source 30 and the image sensor 24 are arranged facing two distinct walls of the spray booth 101. In accordance with this fourth embodiment, the light source 30 faces a side wall of the spray booth and the image sensor 24 faces an upper wall of the spray booth.
In accordance with a fifth embodiment of the present invention, illustrated in the attached figures 9 and 10, the light source 30 and the image sensor 24 are arranged facing two distinct walls of the spray booth 101. In accordance with this fifth embodiment, the light source 30 faces an upper wall of the spray booth and the image sensor 24 faces a side wall of the spray booth. More in detail, the light source 30 is arranged substantially vertically aligned with the spray gun 14, in particular for the purpose of defining a substantially vertical cross-section of the spray pattern 22.
In accordance with a sixth embodiment of the present invention, illustrated in attached figures 11 and 12, the light source 30 and the image sensor 24 are arranged facing two distinct walls of the spray booth 101. In accordance with this fifth embodiment, the light source 30 faces a side wall of the spray booth spraying and the image sensor 24 faces an upper wall of the spray booth 101 itself. More in detail, the image sensor 24 is arranged substantially vertically aligned with the spray gun 14, in particular for the purpose of acquiring a substantially vertical cross-section of the spray pattern 22.
Obviously, in all the aforementioned embodiments from the first to the sixth shown in the accompanying figures, the light source 30 and the image sensor 24 are turned towards the spray pattern 22 through the corresponding side and / or upper wall of the spray booth 101.
Advantageously, in accordance with a further embodiment not illustrated in the attached figures, said control apparatus 1 comprises two light sources 30 configured to generate two corresponding planar electromagnetic radiation beams to define two distinct cross sections of said spraying pattern inclined to each other.
More in detail, in accordance with the latter embodiment, the apparatus 1 according to the invention comprises a first light source configured to generate a first planar light beam extending substantially horizontally, interposed between said spray gun 14 and said product, for generating a horizontal section and a second light source configured to generate a second planar light beam extending substantially vertically to generate a vertical section of said spray pattern.
In this way, with the provision of the apparatus 1 to define two distinct cross sections of the spray pattern 22, it is possible to allow the operators to view the spatial conformation of the spray pattern in three dimensions, while verifying its internal spatial distribution.
Preferably, in accordance with a further embodiment of the present invention, the apparatus according to the invention comprises non-linear optical means (not illustrated in the attached figures) configured to be arranged in correspondence with said image sensor 24 transparent for said first wavelength of said laser beam and opaque with respect to at least said second wavelength different from the first wavelength.
Advantageously, the non-linear optical means are interposed between the image sensor 24 and the spray booth 101. More in detail, the non-linear optical means are mechanically associated with a lens or objective of the image sensor 24, in order to filter the images. electromagnetic radiation acquired by the latter. For example, if the image sensor 24 comprises a camera, the non-linear optical means are suitably fixed on the camera lens. Otherwise, the non-linear optical means can be provided at the spray booth 101. More in detail, the non-linear optical means can be mechanically associated with the transparent walls of the spray booth 101. Otherwise, the transparent walls of the spray booth 101 they can be made at least partially with the non-linear optical material, defining the aforementioned linear optical means substantially integrated with the spray booth.
The non-linear optical media preferably comprise non-linear optical crystals, such as, for example, lithium triborate (LBO) crystals.
In accordance with a particular embodiment of the present invention not illustrated in the attached figures, inside the spray booth 101 installed a movement structure (not illustrated in the attached figures), preferably rotating or turning, provided with a plurality of radial arms and arranged spaced apart from the conveyor belt 4.
Preferably, each arm supports at the free end a spraying device consisting of a spray gun 14. More in detail, three distinct ducts (not shown) lead to each gun 14: a first supply pipe for the product to be sprayed, a second supply pipe for compressed air, to control the opening and closing of the shutter of the gun 14, and a third supply pipe for the compressed air for nebulizing the product to be sprayed and thus form the spray pattern 22. Although in example embodiment described, each arm supports a single gun 14 at its end, structures can also be provided which support on each arm 12 more than one spray gun 14.
Advantageously, the spray guns 14 are controlled by means of a control and processing unit, called "economizer", not represented.
The movement of the structure 10 advantageously causes the movement of the spray guns 14 mounted on the structure itself. For example, in the case of a rotating type structure 10, the latter can rotate at about 15 rpm, while the spray guns 14 move at particularly high peripheral speeds, of the order of about 3 - 4m / s. However, it is understood that the speed of movement of the spray guns 14, as well as of the conveyor belt 4 on which the hides 8 are placed, depends on the type of processing required, as well as on the size of the plant and on the number of spray guns 14 provided in the same.
More in detail, one after the other, the spray guns 14 pass in front of the image sensor 24 and the respective spray patterns are intercepted by the beam of electromagnetic radiation generated by the light source 30, therefore, the image sensor 24 captures in sequence one or more images of all the spray patterns 22 of the spray guns 14 mounted on said handling structure and of their corresponding spray patterns 22.
Advantageously, observing and analyzing on the display device the image acquired by the sensor 24, the operator is able to evaluate the state of the spraying system 1 and to carry out a correct calibration of the same.
The images acquired by the image sensor 24 are displayed on the screen of the display device in corresponding areas dedicated to them. In particular, an area of the screen is associated with a corresponding spray gun 14. Preferably, the same image remains displayed on the screen until the same gun emits a further spray pattern and then a new image is acquired. More in detail, during the calibration phase, the operator observes the image on the display device in order to analyze, check and evaluate at least the following aspects with precision and accuracy:

the adequacy and repeatability of the quantity of product sprayed by the gun 14,
the adequacy (for example in terms of amplitude) and the repeatability of the shape of the pattern 22.

More in detail, by "calibration" of the spraying plant 1 we mean that preliminary phase of the first configuration of the plant itself.
Preferably, the position of the image sensor and in particular of the at least one camera is fixed.
Conveniently, the relative position between the image sensor and the other fixed parts of the apparatus is set during the installation and / or set-up of the apparatus itself. Preferably, this relative position of the image sensor is saved inside the command and control unit.
Advantageously, the command and control unit is configured to activate the image sensor to detect an image at a certain height.
The height at which to detect the image is preferably determined by the command and control unit on the basis of a value detected by an encoder mounted on the structure 10.
Conveniently, the command and control unit is configured to activate the laser source to generate the laser beam at the same altitude on which the camera is also synchronized, in particular for a period of time, in particular reduced and necessary for the acquisition.
Advantageously, the apparatus can comprise two or more spray guns 14 mounted on the same support arm, the fixed position of which is saved inside the command and control unit.
The command and control unit is configured to receive an input signal from an operator to vary the spray gun and height in which to perform the detection of the at least one image.
Advantageously, the spray guns 14 can deliver different products which can have different absorption of the electromagnetic radiation generated by the laser source.
Conveniently, the command and control unit can be configured to contain parameters for the automatic calibration of the image sensor and / or laser source on the basis of the different type of product dispensed by the spray guns.
Advantageously, the system 100 is configured to determine a time advance with which the spraying activation / deactivation command must be sent to a specific gun 14, with respect to the instant in which the gun itself begins to pass over the hide to create / stop the spray pattern 22.
To this end, the processing unit is configured to automatically analyze the images (frames) which are captured in sequence by the sensor 24 of the control apparatus 1 according to the invention, according to a fixed and predefined frequency of the sensor itself. In particular, by calculating the time interval (for example, by counting the number of frames acquired) between the image that is acquired at the instant in which the spraying activation / deactivation command is sent and the image that is acquired in the instant in which there is the actual activation / deactivation of the spraying, the activation / deactivation delay of each gun is determined. Conveniently, this delay is then automatically set, by the processing unit, in the control and processing unit (economizer) of the spray guns 14, as the compensation time anticipation value with which the spraying activation / deactivation command must be sent to the corresponding gun.
Advantageously, the quantities detected during the analysis, control and evaluation described above can be saved inside a storage module of the processing unit and used to be compared with subsequent measurements. In this way, the apparatus according to the invention also makes it possible to identify any drift in the spraying characteristics due to wear and / or aging.
Conveniently, this type of analysis, control and evaluation can be carried out during the calibration phase and / or can be carried out by the operator and the processing unit, preferably live, even during the operation of the spraying system 1, i.e. how much the same acts on the hides which are made to advance the conveyor belt 4.
Furthermore, the processing unit of the control apparatus 1 according to the invention is advantageously configured to detect, in addition to the position of each spray gun 14, also the activation state, ie whether in an open state (in which it delivers the spray pattern), in a closed state (in which it does not dispense any liquid) or in a semi-open state.
Advantageously, the processing unit receives from the control unit (economizer) of the spray guns signals containing the status of the spray guns 14. Conveniently, the processing unit and the control unit are connected to each other and interact with each other during the normal functioning of the apparatus and the plant.
Conveniently, the images acquired by the image sensor 24 are thus correlated to the corresponding status signals received by the control unit, before being sent to the display device.
Basically, in this case, the images acquired live by the sensor 24 are presented to the operator on the display device (for example in video format, preferably slowed down, or with still images), so that the same can check and evaluate the correct functioning of the system itself. Conveniently, this direct evaluation of the operational condition of the spraying plant 1 can then be used by the operator to plan any future maintenance interventions to be carried out on the plant itself. Advantageously, the apparatus can comprise at least one further light source 30, which can be arranged to face a spray pattern 22 of a spray gun 14 distal to the product 8 to be treated and generate at least one electromagnetic radiation beam 32 directed by crossing said spraying pattern 22 thus defining an intersection zone 31, which is therefore defined in an inoperative zone of the spray booth 101, distal to the product 8. Similarly, the apparatus can comprise at least one a further image sensor 24 can be arranged to face said intersection zone 31 in the non-operative area of the spray booth 101.
In this way, the apparatus according to the invention allows to check the operation of the plant 100 also for the non-operative dispensing gun(s) is placed in a distal position with respect to the article 8 to be treated.
Advantageously, the apparatus 1 can comprise a suitable background in order to improve the contrast of the images acquired by the sensor 24.
Preferably, a first software which processes the images acquired by the sensor is loaded and executed inside the processing unit 24 and relating to the spray guns 14 and their patterns 22, so as to make a comparison between these and at least one image, previously stored or acquired, relating to an ideal spray pattern.
More in detail, this first software is configured to obtain from the images acquired by the sensor 24 some parameters of the spray pattern 22, in particular with regard to its geometry and / or its amplitude, and to compare them with the characteristic parameters, previously stored or acquired, of an ideal spraying pattern.
Conveniently, therefore, this software loaded and executed in the processing unit allows the latter to automatically discriminate, by analyzing each pattern 22 carried out starting from the images acquired by the sensor 24, any malfunctions of the spray guns 14.
Advantageously, in the event of a negative outcome of said comparison, i.e. in the presence of a malfunction of the spray guns 14, the first software is also set up for the processing unit to command the generation of a warning and / or an alarm for the operator, visual (for example on the display device) or audio.
Advantageously, said first software loaded and executed in the processing unit is also configured to compare the width of the spraying patterns 22 of all the spraying guns 14 mounted on the same handling structure so as to check whether all the spray guns 14 generate spraying patterns of the same amplitude and / or if the latter is in line with the ideal one that has been set in the spraying system 1 for that specific process. This is particularly advantageous as it allows to evaluate, as well as to compare, quickly and / or automatically the functionality (in particular in terms of the width of the spray pattern) of all the spray guns 14 intended to spray the treatment liquid on a specific hide, thus avoiding the need to manually adjust and control, gun by gun, the width of the corresponding spray pattern.
Preferably, images are acquired by means of the sensor 24 which concern both the outlet of the product from the spray guns 14, ie in correspondence with the nozzle of these, and the corresponding patterns 22 obtained from the corresponding outlets. In particular, for this purpose, a second software is loaded and executed inside the processing unit which processes several images, acquired by the sensor 24 and relating to the spray guns 14 and their patterns 22, in order to obtain parameters indicative both of the product output from the nozzle of each gun 14 and of the corresponding pattern 22 generated, in order to evaluate how the latter varies according to the output. The parameters thus obtained can then be sent to the display device in order to allow any manual correction by the operator and / or, preferably, they can be suitably processed by the processing unit to generate a regulation command, in a closed circuit, to be sent to the control and processing unit (economizer) of the spray guns 14. Conveniently, the processing unit can be configured so that the data resulting from the processing, described above, carried out by the first and / or second software, are organized in a report which is then presented on the display device and / or can be printed. More in detail, this report documents what happened during the passage of the hide inside the spraying system and, suitably, it can be used by the operator for the appropriate assessments and / or it can be provided to the customer in order to certify the quality of the spraying carried out.
Advantageously, the processing unit can be configured to store the data which have been obtained, by means of the processing carried out by the first and / or second software, by processing the images acquired by the sensor 24 and which are indicative of the performance and any malfunctions of the spray guns 14. Furthermore, the processing unit can be configured to perform statistical analyses on the data thus stored within the unit itself. Conveniently, even these data can then be presented to the operator on the display device and / or through a report, in order to allow the operator himself to evaluate the opportunity to carry out preventive replacement and / or maintenance of the spray guns 14 of the spraying system 1.
The present invention also relates to a method for controlling the functionality of at least one spray gun (14) of a spraying system or device, in particular which can be made by means of at least one improved control apparatus 1 of the type described above and of which, for simplicity of explanation, the same numerical references will be maintained.
The method according to the invention comprises at least the operating steps described in detail below.
Preliminarily, the method advantageously provides for a step of setting up a control apparatus 1 according to the invention applied to a spraying plant (or device), preferably externally with respect to the spray booth 101.
The method therefore provides for an illumination stage of said spray pattern 22 of said spray gun 14 by means of at least one light source 30 by means of at least one beam of electromagnetic radiation directed to cross said spray pattern 22 defining an intersection zone 31.
Preferably, the illumination phase provides for illuminating the spraying pattern 22 by means of a laser beam, in particular substantially planar adapted to illuminate at least a cross section of said spray pattern 22 in correspondence with said intersection zone 31.
The method therefore provides at least one step for capturing at least an image of said intersection zone 31 of said spray pattern 22 by means of at least one image sensor 24.
Advantageously, the capture step is carried out continuously, ie the capture step provides for constantly monitoring at least the intersection zone 31 of the spray pattern 22.
The method therefore provides for a step of sending of said at least an image thus captured to a processing unit in data connection with said image sensor 24 and to a display device, in which it is presented to the operator. In particular, the display device may comprise a screen or the like, arranged externally with respect to the spray booth 101 and easily visible by the operator.
The method therefore provides a step of analyzing and checking, on the basis of said at least one image, the characteristics of said spray pattern 22.
Advantageously, the lighting step can be carried out by means of two light sources 30 configured to generate two corresponding beams of planar electromagnetic radiations to define two distinct cross sections of said spray pattern inclined to each other.
More in detail, in accordance with the latter embodiment, the method according to the invention provides for carrying out the lighting step by means of a first light source configured to generate a first planar light beam extending substantially horizontally, interposed between said spray gun 14 and said manufactured article, to generate a horizontal section and a second light source configured to generate a second planar light beam extending substantially vertically to generate a vertical section of said spray pattern.
In this way, with the provision of the method of defining two distinct cross sections of the spray pattern 22, it is possible to allow the operators to visualize the spatial conformation of the spray pattern in three dimensions, while verifying its internal spatial distribution.
From what has been said it is clear that the apparatus (and the method) according to the invention is much more advantageous than the traditional ones in that:

it allows the correct operation of at least one spray gun to be monitored quickly and easily;
it allows to detect the shape of the spray pattern in a safe and reliable way;
it can be applied to different types of spray systems or devices already on the market, in particular to different spray booths already on the market;
allows to monitor the correct operation of at least one spray gun during its operation;
supports and facilitates the control activity carried out by the operator both at the time of the initial calibration of the spraying system itself, as well as preferably during the normal operational operation of the latter;
makes it easy to identify any malfunctions of at least one spray gun;
automatically warns the operator of the presence of any malfunctions of the system itself, in order to allow manual intervention by the operator himself;
it allows to automatically correct any malfunctions of the spraying system itself;
provides the operator, as well as the customer for whom the hide is intended, a certification of the spraying carried out by the plant itself;
provides the operator with useful information for planning preventive maintenance interventions on the spraying system itself;
it is reliable and avoids situations of slowdowns or blocks of the same;
the method according to the invention can also be easily implemented in spraying systems for already existing hides.

The present invention has been illustrated in a preferred embodiment thereof, but it is understood that executive variations may be applied to them in practice, without however departing from the scope of protection of the present patent for industrial invention.

Claims

Improved control apparatus (1) for a plant (100) or a spraying device, said plant (100) or device comprising at least one spray gun (14) configured to spray a treatment liquid on at least one product (8) to be treated by generating a corresponding spray pattern (22),
said apparatus comprises:
- at least one light source (30) arranged to face towards said spray pattern (22) and configured to generate at least one electromagnetic radiation beam (32) directed to cross said spray pattern (22) thus defining an intersection zone (31);

- at least one image sensor (24) arranged to face towards said intersection zone (31) of said spray pattern (22) and configured to acquire at least an image of said intersection zone (31) of said spray pattern (22),

- a processing unit in data link with said image sensor (24) which receives said at least one image captured by said at least one image sensor (24), said processing unit being configured to process the image (24) thus received, preferably so as to calculate and / or define the characteristics and / or the quality of said spray pattern (22) and / or to send the received and / or processed image to a display device in which it is presented to the operator;

characterized by the fact that said laser beam generated by said light source (30) comprises a first wavelength and by the fact that said image sensor (24) comprises at least one optical filter adapted to prevent the detection of electromagnetic radiation comprising second wavelength different from said first wavelength of said laser beam.
Apparatus (1) according to claim 1, characterized in that said electromagnetic radiation beam (32) has a substantially planar shape and illuminates at least one cross section of said spray pattern at said intersection zone (31).
Apparatus (1) according to claim 2, characterized in that said light source (30) is a laser source able to generate a substantially planar laser beam which defines said cross section of said spray pattern (22) in correspondence of said intersection zone (31).
Apparatus (1) according to claim 3, characterized in that said optical filter is configured to allow the passage of electromagnetic radiations with said first wavelength between 650nm and 680nm and preferably of about 660nm.
Apparatus (1) according to one or more of claims 2 to 4, characterized in that it comprises two light sources (30) configured to generate two corresponding planar electromagnetic radiation beams to define two distinct cross sections of said spray pattern between them tilted.
Apparatus (1) according to claims 4 and 5, characterized in that it comprises optical means operatively associated with said image sensor (24), transparent for said first wavelength of said laser beam and opaque with respect to at least said second different wavelength than first wavelength.
Apparatus (1) according to claim 6, characterized in that said non-linear optical means are mechanically mounted on said image sensor (24).
Apparatus (1) according to one or more of the preceding claims, characterized in that said processing unit is connected to a control and processing unit of said at least one spray gun (14) and / or said processing unit and said command and control unit are implemented within the same processor, said processing unit being configured to receive a signal containing operating parameters of said spray gun and to associate said signal with said image acquired by said image sensor and preferably for sending a corresponding signal to said command and control unit to automatically control a variation in the operating parameters of said spray gun (14).
Apparatus (1) according to one or more of the preceding claims, characterized in that said optical filter has a transmission coefficient higher than 90% for electromagnetic waves having said first wavelength.
Apparatus (1) according to one or more of the preceding claims, characterized in that said optical filter defines a passband with transmission coefficient higher than 80% in a range of values of said first wavelength.
Apparatus (1) according to one or more of the preceding claims, characterized in that the position of the image sensor is fixed.
Apparatus (1) according to one or more of the preceding claims, characterized in that the relative position between the image sensor and the other fixed parts of the apparatus is set during the installation and / or set-up of said apparatus; said relative position of the image sensor is saved inside said command and control unit.
Apparatus (1) according to one or more of the preceding claims, characterized in that said command and control unit is configured to activate the image sensor to detect an image at a given altitude
Plant (100) for spraying a treatment liquid on at least one product (8) to be treated by generating a corresponding spray pattern (22), said system being characterized in that it comprises at least one control apparatus (1) according to one or more of the preceding claims, said control apparatus control (1) being arranged externally with respect to a spray booth (101) in which said at least one spray gun (14) is housed.
Method for controlling the functionality of at least one spray gun (14) of a spray plant or device by means of at least one control apparatus (1) according to one or more of the preceding claims, which method comprises at least the following operating steps:
- a phase of illumination of said spray pattern (22) of said spray gun (14) by means of at least one light source (30) configured to emit at least one beam of electromagnetic radiation directed through said spray pattern (22) defining a intersection zone (31);

- a step of capturing at least an image of said intersection zone (31) of said spray pattern (22) by means of at least one image sensor (24);

- a step of sending said at least an image thus captured to a processing unit in data connection with said image sensor (24) and / or to a display device, in which it is presented to the operator;

- a step of analyzing and checking, on the basis of said at least one image, the characteristics of said spray pattern (22).