DESCRIPTION

The invention concerns an improved drying system for thin flexible elements. The system is used to dry thin flexible elements in general, preferably to dry hides.

Therefore, the system that is the subject of the invention is especially useful in tanneries, where it can be used to dry the wet hides that have just undergone wet treatments.

It is known that in tanneries the hides, which are wet when they leave the units where they have undergone the wet treatments, must be properly dried before undergoing the successive processing steps that result in the finished product.

The drying operations, as is known, are carried out by means of dryers of various types that operate according to different principles.

The so-called vacuum dryers are known, for example, in which the hides are dried through the evaporation of the water they contain, in an environment where vacuum is produced.

Drying systems are also known that use hot air dryers and in which the hides are spread on separate and distinct panels that transit in the dryer with intermittent motion owing to the action of moving chains to which said panels are connected.

Drying systems are also known in which the hides are laid and spread the continuous belt that travels at continuous and controlled speed in the dryer. All the dryers described above include also a loading station for the hides, where operators or automatic means arrange the hides to be dried spreading them on a flat surface and stretching them in order to avoid the formation of creases during the drying step.

A special feeding line connects the loading station to the inlet of the dryer in order to introduce the hides to be dried, while a special unloading line connects the outlet of the dryer to an unloading area from where the dried hides are unloaded, also in this case by operators or automatic means.

The loading and unloading stations often coincide in a single loading/unloading station from which the dryer feeding line and the dried hide unloading line branch off.

In this case the operators or the automatic means, arranged at the level of the loading and/or unloading station, provide for continuously unloading the dried hides that leave the dryer and for loading the hides to be dried that must be transferred into the dryer in order to undergo the drying process.

All the known drying systems, however, pose the recognized drawback that they carry out the simple hide drying operation, without allowing the hide to undergo any kind of auxiliary treatment before entering the dryer, after the loading station, or once having dried but before the unloading station.

Before being introduced in the dryer the hides often need, for example, to be softened with special substances or resins, or to be treated with products intended to eliminate defects that, if not eliminated, might worsen after the drying process.

Analogously, after the drying treatment it might be necessary to treat the dried hides with other products intended to make them especially soft and flexible, or to protect and preserve them from external aggressive agents, or even to perfume them with perfumed substances.

In all these cases it is necessary to carry out the treatments outside the drying line, which means additional costs for handling the hides and longer treatment times mainly due to the increased handling times.

There are no known hide drying systems with continuous cycle that, during the drying cycle, allow treatment products to be applied to the wet hides before they enter the dryer.

There are, however, known treatment lines and methods for applying products to dried hides, described for example in documents WO 2006/100055 A1 , EP 0 739 715 A2, EP 0 296 999 A1 and WO 2007/008025 A .

These documents, in fact, disclose treatment processes and systems that include conveyor lines suited to convey the hides to one or more stations where they are treated by spreading finishing substances of various types on one or both of their surfaces.

Said finishing substances may be synthetic films, as described in documents WO 2006/100055 A1 , EP 0 739 715 A2 and EP 0 296 999 A1 , or colouring substances, as described in document WO 2007/008025 A1.

These systems include also drying ovens that act on the substance spread on the hide in order to dry or polymerize it, and in any case to fix it on the hide where it has been applied.

All the processes and systems described in the above mentioned documents, however, have some recognized limitations as well as some recognized drawbacks.

A first limitation lies in that said processes and systems are substantially finishing processes and systems suited to treat already dried hides and therefore not suited to be used with wet hides.

Another limitation is represented by the fact that the dryers with which said systems are provided do not make it possible to dry wet hides coming from the wet treatments and to make them reach the desired degree of humidity.

In other words, none of the systems described in the documents mentioned above can work as a simple dryer and perform only the hide drying operation. Furthermore, each one of said processes and systems is capable of performing only the treatment for which it has been designed and therefore is characterized by a high degree of rigidity.

The present invention intends to overcome all the limitations and drawbacks described above.

In particular, it is a first object of the invention to provide an improved drying system for thin flexible elements, particularly suitable for treating hides, which allows products to be applied to the hides to be treated directly in the drying system, while the hides advance in the drying line.

It is another object of the invention to allow the application of products to be performed before the drying process, upstream of the dryer.

It is a further object of the invention to allow the application of products to be performed after the drying process, downstream of the dryer.

It is a further object of the invention to allow said application of products to be carried out in any point of the conveyor line that transports the hides from the loading station to the dryer and from the latter to the unloading station.

It is another yet not the least object of the invention to provide an improved method for drying hides with a product application step integrated in the drying cycle and performed in the same processing line.

The objects described above are achieved by an improved drying system in accordance with the contents of the main claim, to which the reader should refer for the sake of brevity.

Other characteristics of the improved drying system that is the subject of the invention are described in the dependent claims.

The improved drying system that is the subject of the invention may include the combination of one or more dryers of any type, with one or more hide loading and/or unloading stations, connected to each other by means of one or more conveyor lines arranged and structured in any way.

Furthermore, according to the invention, in the drying system the movement of the hides along the conveyor lines may take place continuously or intermittently.

Finally, the loading and/or unloading stations may be integrated with each other, meaning that the hides can be unloaded also in the loading station and vice versa, or they may also be separate.

Advantageously, the improved drying system of the invention makes it possible to carry out treatments on wet hides before the drying cycle and directly in the drying line during the advance of the hides towards the dryer, which is not possible in the current state of the art.

Advantageously, the improved drying system of the invention makes it possible to carry out treatments on the hides after the drying cycle and directly in the drying line while the hides advance towards the unloading station, which is not possible in the current state of the art.

In this second usage configuration, the improved drying system of the invention may be, in some cases, a valid and more economic alternative to corresponding finishing lines of the known type, for example those mentioned in the patent documents examined above.

Still advantageously, said opportunity to perform the treatment on the hides in the drying line does not involve additional transport and handling costs.

To advantage, as it is not necessary to perform any treatment outside the drying line, the time needed by the hides to pass through the system remains unchanged, which is an advantage in terms of costs and productivity.

Another advantage, which is not the least one, lies in that the drying system of the invention can be used also for simply drying hides.

The objects and advantages described above will be highlighted in greater detail in the description of a preferred embodiment of the invention that is supplied as an indicative, non-limiting example, with reference to the enclosed drawings, wherein:

Figure 1 shows a schematic view of the improved drying system that is the subject of the invention;

Figures from 2 to 5 show schematic views of details of the system of Figure 1 in different construction variants. The improved drying system forming the subject of the invention is shown in a schematic view in Figure 1 , where it is indicated as a whole by 1.

It should be noted above all that the view of Figure 1 is intentionally schematic, as it represents one of the multiple possible configurations of the drying system, which can vary according to the user's needs.

Furthermore, the improved drying system of the invention shown in Figure 1 is described herein considering the case where it is used for drying thin flexible elements consisting of hides.

It is however evident that it can also be used for drying thin flexible elements different from hides, like for example fabrics or the like.

It can be observed that it comprises a loading and/or unloading station indicated as a whole by 2, in which the hides P to be treated, shown in Figures from 1 to 5, are arranged so that they are spread on a plane surface.

In the case described herein the loading and/or unloading station 2 is one and both the unloading of the treated hides P and the loading of the new hides P to be treated are carried out there by operators or through automatic means like automated toggles and similar devices.

In a different embodiment of the invention the system can in any case be provided with two separate and distinct stations for loading and unloading. The system 1 includes also the dryer that is schematically indicated as a whole by 3 and can be a dryer of any type, operating continuously or intermittently, suited to dry the hides that transit within it.

A conveyor line, indicated as a whole by 4, creates a closed circuit including the loading and/or unloading station 2 and the dryer 3.

The conveyor line 4 can be carried out in different ways according to different techniques known per se.

For example, it may consist of a continuous conveyor surface, for example a belt or a net, on which the hides to be dried are spread one after the other, and which advances by means of parallel and spaced chains that support it at the level of its sides.

According to another embodiment of the invention, the conveyor line may consist of a plurality of separate and distinct panels arranged one after the other, which advance owing to the action of rollers that support them at the level of the two opposing sides and slide inside parallel tracks.

Furthermore, the hides may transit horizontally or in inclined or even vertical position inside the dryer 3.

In this regard, the dryer 1 will be preferably of the type in which the hides are dried after being laid and stretched, in order to obtain the maximum usable surface.

This also allows the dryer to be used to stretch hides that may have been previously dried.

In the conveyor line 4 it is possible to identify a feeding line 5 for conveying the hides P to be dried from the loading and/or unloading station 2 to the inlet 3a of the dryer 3 and an unloading line 6 for conveying the dried hides P from the outlet 3b of the dryer 3 to the loading and/or unloading station 2.

According to the invention the system comprises one or more treatment stations 7 for the application of products to the hides P.

According to different embodiments that are all schematically shown in Figure 1 , the treatment station 7 can be arranged in the position indicated by 20 that coincides with the loading and/or unloading station 2.

According to another embodiment, the treatment station 7 is arranged in any position of the feeding line 5, where it can be located in position 30, immediately downstream of the loading and/or unloading station 2, or in the position indicated by 40, at the level of the inlet 3a of the dryer 3, or again in any intermediate position, indicated by 50, along the feeding line 5.

According to a further embodiment, the treatment station 7 can be arranged in the unloading line 6, in the position indicated by 60, at the level of the outlet 3b of the dryer 3.

In general, the treatment station 7 can be arranged in any position in the system 1.

Obviously, the system can be provided with one or more treatment stations 7 arranged according to the embodiments described above.

Each one of the treatment stations 7 is provided with means 8 for applying the products to the hides P to be treated, wherein said application means can come in different construction forms.

So, for example, it can be observed in Figure 2 that the product application means 8 comprise a plurality of spraying nozzles 9 arranged aligned one after the other along the rectilinear direction Y, orthogonal to the direction X of advance of the hide P, defined by the delivery pipe 9a conveying the products to be applied. In particular, the spraying nozzles 9 can be also arranged according to two or more rectilinear directions Y parallel to each other.

Furthermore, the spraying nozzles 9 can be directed against the upper side or against the lower side or against both sides of the hide P.

According to another embodiment of the invention shown in Figure 3, the application means 8 comprise at least one spraying head 10 associated with moving means 11 that move it on the hide P to be treated according to two axes X, Y that are perpendicular to each other.

In this way it is possible to reach any point of the hide P by properly combining the two movements through a computer controlled program.

Also in this case the spraying head 10 can be directed towards the upper surface or towards the lower surface of the hide P or towards both of them. According to a further embodiment of the invention shown in Figure 4, the moving means 8 of the spraying head 10 are constituted by an anthropomorphic robot 12 controlled by the computer.

Finally, according to another but not the last embodiment shown in Figure 5, the application means 8 are constituted by a coater 13 that spreads a film F on the underlying hide to be treated P exploiting gravity.

It is clear that the improved drying system of the invention can be provided with any number of treatment stations 7, each one of which can apply to the hide P a different product suited to give it special characteristics.

Furthermore, in the system each treatment station 7 can be provided with one or more spraying means 8 already described.

The treatment stations can be fixed or moving, and in the latter configuration they are particularly useful when the advance of the hides in the drying system is continuous.

Finally, the system is provided with washing means suited to remove the residues of the treatment products from the belt, the nets or the panels on which the hides are spread.

Therefore, the above description clearly shows that in the improved system of the invention the surface treatments on the hides P are carried out in the drying line while these transit through the dryer 3 and the loading and/or unloading station 2, therefore without requiring any operation to be performed outside the processing line and thus without additional costs.

In this way, the cycle time remains substantially unchanged, as the operations for applying the products are performed while the hides are transported from the loading station to the dryer or from the dryer to the unloading station.

Furthermore, in the case of application of some products to the hides after the drying cycle, the system of the invention does not need to use especially dedicated finishing lines.

Therefore, according to the above, the system of the invention achieves all the set objects.

As already explained, the system of the invention can be provided with one or more loading and unloading stations, each one of which may perform the loading only, the unloading only, or both operations.

Furthermore, said loading and unloading stations, as well as the dryers, can have any shape and characteristics and can belong to the known art or not. The conveyor lines and in particular the feeding line and the unloading line can be one or more than one, and transport the hides continuously or intermittently. In the construction stage the drying system of the invention may be subjected to changes or modifications that are neither described herein nor illustrated in the drawings.

Said construction variants or modifications must all be considered protected by the present patent, provided that they fall within the scope of the claims expressed below.

In the cases where the technical characteristics illustrated in the claims are followed by references, these have been added only with the aim to facilitate the comprehension of the claims themselves, and therefore said references do not have any limiting effect on the degree of protection to be granted to each element they identify only by way of example.