The present invention generally relates to an industrial rotary booth for treating tannery leathers by spraying, in nebulized form, covering products such as paints, pigments, resins, oils, paraffins, glues and so on, in the form of suitable mixtures. As known, in the tanning industry of animal leathers or faux leathers (leatherette), spraying equipment or machines, commonly called "booths", are available, adapted to be used to spray various covering products on the leathers such as paints, pigments, resins, oils, paraffins, glues or similar natural and/or chemical products.

As is also well known, painting by spraying is one of the most important leather finishing operations in the processing cycle of the tanning industry, which envisages ample available space in the factory, due to the extension of the plants with which it is carried out.

Basically, in the tanning field, painting leathers consists of covering the grain side (i.e., the noblest and most valuable side of the leather) with one or more layers of painting, covering and/or coloring material, in the form of an elastic, thin and uniform film, applied by spraying and in a lesser or greater amount, depending on the covering capacity to be obtained.

The main risk also associated with painting leathers is obviously the environmental pollution which it causes in the workplace; to eliminate or at least reduce this risk, special industrial spray booths must be used, which can essentially be of two types:

- open spray booths, i.e., provided with an open surface on one or more sides;

- closed, watertight spray booths, i.e., with a closed surface on all sides, with the exception of "technical" openings which can be closed by doors or gates, adapted to allow the entry of the leathers involved in the spraying operations.

A further classification of the industrial spraying booths used in the tanning industry derives from the type of spraying that is carried out therewith, which can be manual (less and less widespread) or automatic (without the intervention of personnel).

A typical known system for spraying leathers generally comprises a conveyor belt for advancing leathers along a given linear direction, a closed industrial booth within which, by means of relative spray guns, the deposition of the covering products occurs, and a fume suction and abatement system, by means of which the exhalations of the covering products which are deposited on the leathers are sucked and filtered.

The known systems for painting or spraying leathers use, in particular, a fume extraction system deriving from the paint suspended in the air in the industrial booth which can be further classified as rotary-type (in the circular or so-called, improperly, elliptical variant) or alternating-type.

Specifically, a common circular rotary booth, visible in figure 1 where it is indicated with C and also in the prior art document published with GB2098885 A, has a central shaft N, arranged inside the spraying chamber S and operatively connected to motorization means M, having the function of distributing the covering fluid material (color, paint or anything else, in mixture), useful for spraying on the leather, to the spraying means to which the compressed air ducts necessary for the operation of the spraying means themselves refer.

The circular rotary spray booth C of the known type further comprises a plurality of load-bearing arms B (usually in the number of eight or twelve), arranged radially and integral with the motorized central shaft N from which they thus take the rotation movement, while the spraying means generally comprise a plurality of fixed guns F which are installed at the ends of the load-bearing arms B and spray the fluid covering material in a nebulized form on the surface of the leather P to be treated which, in turn, is placed on the upper surface of a conveyor belt T, generally made with parallel and close nylon threads, which has a width G and advances along a preset linear direction W by means of the use of an inverter, at a preset speed (usually between 4 and 22 meters/minute).

At the end of each load-bearing arm B, one, two or sometimes three fixed spray guns F can be installed, each of which also has a supply circuit thereof for the fluid covering material which is sucked by a pump arranged on the side of the rotary booth C, while the compressed air circuit provides for a correct nebulization of such fluid material.

Furthermore, there is a reading bar installed upstream of the industrial rotary booth C, which has the function of determining the position of the leather P, the surface thereof and the contour thereof, so that an electronic control system, which stores the size and shape of the leather P itself, is capable of determining the opening and closing of the spray guns.

The known circular rotary booths are preferable for the effectiveness and efficiency with which they allow carrying out the spraying treatment of the leathers since each of the spray guns, performing precisely a circular motion along a circumference of a given radius "r" and center O integral with that of the central shaft N rotating around a vertical axis, applies the fluid covering material on the leathers according to an articulated arcuate design, so-called crossed rows to form a net which, due also to the number of spraying passages performed on the leathers by the dispensing guns F, makes substantially imperceptible to the human eye and compensates for any treatment imperfections due to uneven operations of the spray guns F and thus avoids stopping the operation of the rotary booth C or at least limits the frequency of machine stops.

Faced with these advantages, however, circular rotary booths have the disadvantage of requiring significant spaces in the factory, not always available or conceivable by the entrepreneur.

For this reason, alternative industrial booths are sometimes used, which have been available on the market for some time, which have smaller dimensions; they comprise one or two guides, which are transverse with respect to the translation (or advancement) movement of the leathers on the conveyor belt and on each of which a gun-carrying carriage runs; special motors, adjustable with inverter and related chains or drive belts, determine the alternative linear movement of the carriages, as well as appropriate tubes carry both the compressed air and the fluid covering material (generally color) necessary for the operation of the spray guns and the treatment of the leathers therewith.

In industrial spray booths of the alternative type, whenever the carriage moves in a transverse direction, the spray guns apply the covering material, on the advancing leather, according to a design or pattern which is easily perceptible by the human eye and which, inevitably, affects the final quality of the product, to the point that such industrial booths are used sporadically and only for certain spraying steps. For their part, the common industrial rotary booths of the parallel type (improperly defined also as "elliptical") are based on the same operating principle as the alternative booths (although they are in fact rotary).

In fact, the closed annular trajectory followed by the spraying means of the so- called "elliptical" booths during the treatment consists of two straight and parallel central sections - identified exactly in the part above the conveyor belt and the leathers progressively extended thereon -, at which the spraying means work, and of two curved lateral sections (essentially two semicircles) - identified laterally and outside the conveyor belt and, therefore, definable as "dead" sections from a point of view of the spraying treatment of the leathers - which connect the aforesaid two straight sections and at which the spraying means are closed, non-operational. Parallel (or elliptical) type rotary spray booths of the prior art, an example of which is shown in the Italian patent no. 102019000009714, have a rectangular structure and a length (measured in the advancement direction of the leathers on the conveyor belt) having a value between 50% and 30% of the length of the circular rotary booths.

The parallel rotary booths include two gear wheels, joined together by mechanical transmission means (such as a belt or a chain) which define the aforesaid closed trajectory in parallel straight sections interspersed with arcuate sections; one of such wheels is motorized, while a plurality of spray guns, to which special air pipes and covering material to be applied are connected, are fixed to the transmission means and a central distribution shaft feeds both the air circuits and the circuits of the fluid covering material and/or dye dispensed by the spray guns.

Parallel industrial booths, in addition to being inherently rather complex from a constructional point of view, also have the disadvantage that the transverse movement of the spraying means, combined with the movement of the conveyor belt advancing the leathers, generates a linear design formed by a series of crossed strips (or lines) which, similar to the alternative industrial booths, do not provide good results; not surprisingly, these booths have a limited application in the tanning industry, usually being used to deposit the so-called "background color", on which the final color layers are then deposited with other spray booths. Based on the operating features offered by the types of booths currently on the market, it is concluded, as already mentioned above, that circular rotary booths, although bulkier, offer the best performance in terms of surface finish of the leather by spraying treatment of a covering material and/or dye (such as a paint).

In any case, the rotary spray booths have a significant disadvantage, largely underestimated for the obvious negative effects thereof, linked to the positioning of the extraction system of the fumes and/or particulate generated by spraying the covering material on the leather, useful to prevent drops of material dispensed by the spraying means from not being deposited - for any reason, even accidental - where programmed and desired, i.e., on the leather.

In fact, although such a suction system is installed near the load-bearing arms of the spraying means, it is arranged - as it occurs in the spray booths shown in the Italian patent 102019000009714 and in the patent application GB2098885 A1 - at a distance from the latter which is not uniform and homogeneous and, more generally and in any case, not rational.

This implies that, in the known type of rotary booths, the flow rate and direction of the continuous airflow produced by the suction means must be carefully studied and designed according to the different distance of the suction means from the spraying means, in order to try to ensure that the spraying treatment conditions of the leathers are at least sufficient and adequate for the expected result. Furthermore, if the flow rate and flow direction are not correctly sized and oriented, as sometimes occurs, there are drawbacks such as:

• build-up of spraying material at specific areas inside the spray booth which are difficult to reach, so that the maintenance and cleaning operations of the booth itself are subsequently more complicated;

• rebounds of the covering material or spraying paint on the leather during the processing step, with all the negative effects which this entails for the quality of the leather itself;

• more commonly and more simply, an excessive consumption of material to be sprayed caused by the fact of including an excess airflow which ends up undesirably and incorrectly capturing and directing part of the material to be sprayed being dispensed by the spraying means.

In this regard, consider, for instance, the emblematic case - shown in figures 1 and 2 and also in the prior art document published with GB2098885 A - in which the suction means A are arranged in the lower part of the rotary spray booth C of the prior art, along the lateral sides of the collection plane R of the traditional substantially rectangular or in any case square shape, placed below the spraying means F inside the load-bearing structure U and provided with an upper face R _u adapted to receive by falling the particulate of the painting mixture to be sprayed on the leather P: indeed, it can be noted that the consequent distance of the suction means A from the spraying means F is not uniform and constant at least along the linear direction W, with all the complications cited above that this entails. Therefore, starting from the awareness and existence of the above disadvantages of the current state of the art, the present invention intends to remedy it.

In particular, the main purpose of the invention is to provide a rotary booth for treating leathers by spraying which allows to rationalize the airflow of the suction means inside the booth, improving it and making it more efficient than that of the prior art rotary spray booths.

As part of such a purpose, it is task of the invention to devise a rotary booth for treating leathers by spraying in which the suction means cause a dispersion of the painting material to be applied on the leather which is almost null or at least slightly less than the equivalent booths of the known type.

It is another task of the present invention to indicate a rotary booth for treating leathers by spraying which, with respect to the prior art, allows to reduce the uncontrolled rebounds of the spraying paint material on the leather during the processing step inside the load-bearing structure.

It is a further task of the present invention to provide a rotary booth for treating leathers by spraying which, in the cognitive sphere of the main purpose thereof, makes it possible to obtain leathers of a higher quality with respect to those ones obtainable through the similar known spray booths.

It is further the task of the invention to specify a rotary booth for treating leathers by spraying which makes the cleaning operations which workers must periodically carry out in the spraying chamber easier than the current state of the art.

It is a further purpose of the present invention to develop a rotary booth for treating leathers by spraying which, in view of the advantages with respect to the prior art which it is intended to achieve, remains substantially unchanged in the overall dimensions.

Said purposes are achieved by means of a rotary booth for treating leathers by spraying according to the appended claim 1 , as hereinafter referred for the sake of brevity of disclosure.

Further detailed technical features of the rotary booth for treating leathers by spraying of the invention are reported in the related dependent claims.

The aforesaid claims, hereinafter specifically and concretely defined, are intended as an integral part of the present description.

Advantageously, the rotary booth for treating leathers by spraying of the invention allows to optimize and rationalize the airflow of the suction means inside the booth, making it better with respect to that of the rotary spray booths of the prior art.

This is by virtue of the fact that the rotary booth for treating leathers by spraying of the invention has suction means distributed according to a pattern which coincides with the spatial distribution of the spraying means in the lower part of the load- bearing structure of the rotary booth itself.

In other words, in the rotary booth of the present invention, used to treat leathers by spraying, the suction means suck at the spraying area, in the lower part of the load-bearing structure, cooperating with the primary circumferential arcs (belonging to the closed annular trajectory) along which the spraying means take the working condition in which they dispense the fluid painting mixture on the leather advancing on the conveyor belt.

In essence, therefore, the suction means and the spraying means of the rotary booth of the invention are advantageously arranged on two respective planes, generally horizontal, parallel and spaced from each other and according to the same and superimposable arcuate configuration.

What has just been highlighted in relation to the rotary booth of the invention is in no way found in the prior art documents published as IT2019000009714 A1 and GB2098885 A1 respectively; in fact:

• in the previous document published as IT2019000009714 A1 (and granted with the same number), observing the conveyor belt in plan (seen from above), the suction means operate according to a linear configuration which does not follow and is not superimposable on the trajectory travelled by the spraying means above the conveyor belt; moreover, in such a previous document the suction means - which are presented in the form of a pair of lateral suction tanks opposite each other, symmetrically arranged with respect to the longitudinal axis of symmetry of the conveyor belt - are arranged laterally to the conveyor belt and externally to the transverse dimension thereof (thus, also externally to the encumbrance of the spraying means above the belt itself) and not at the spraying area, again observing the conveyor belt in plan;

• in the previous document published as GB2098885 A1 , as clearly visible in the drawings thereof, the suction means still operate according to a linear configuration which does not follow and is not superimposable on the trajectory travelled by the spraying means above the conveyor belt.

It follows that the suction efficiency, by means of an airflow, at least of the fumes produced by the spraying treatment inside the load-bearing structure is certainly better and increased in the rotary booth of the invention with respect to that of the equivalent booths of a known type more closely comparable thereto, shown in the aforesaid two prior art documents.

Still advantageously, the rotary booth for treating leathers by spraying of the invention does not require an oversizing of the suction means, as typically occurs in the known equivalent rotary booths: this is advantageously reflected, for the rotary booth of the invention, on the one hand, in a design of such a constructional unit which is simpler with respect to the prior art and, on the other hand and consequently, in an uncontrolled spreading, in the inner areas of the load-bearing structure, of the covering material to be sprayed on the leathers which is more contained with respect to the prior art.

In an equally advantageous way, the rotary spray booth of leathers of the present invention maintains, in the volume confined by the load-bearing structure, better cleaning conditions (with the same product dispensed by the spraying means) and at least satisfactory cleaning conditions for a longer time with respect to the known type of rotary booths comparable thereto. Likewise advantageously, precisely because the cleaning of the rotary booth of the invention is better, in use, with respect to the rotary booths for treating animal leathers by spraying of the prior art, the operators are further aided when they must perform maintenance and dirt removal operations which are thus less complicated and faster with respect to what is currently necessary to implement. Equally advantageously, the rotary booth for treating animal leathers by spraying, the object of the invention, has an overall encumbrance at least equivalent to that of the common rotary booths of equal use of the prior art, while achieving the main advantages mentioned above.

Said purposes and advantages will result to a greater extent from the following description, related to preferred embodiments of the rotary booth for treating tannery leathers by spraying of the invention, given by way of indicative non limiting illustration, with the aid of the accompanying (in part yet mentioned) drawings in which:

- figure 1 is a simplified assonometric view of a rotary booth of the prior art;

- figure 2 is a diagrammatic, exemplary and explanatory plan view of figure 1 ;

- figure 3 is a simplified assonometric view of a rotary booth of the invention;

- figure 4 is a diagrammatic, exemplary and explanatory plan view of figure 3;

- figure 5 is a diagrammatic and explanatory side view of an enlarged constructive detail of figure 3;

- figure 6 is a diagrammatic and explanatory side view of an enlarged constructive detail of an executive variant of the rotary booth of figure 1.

The industrial rotary booth of the invention, used to treat tannery leathers P by spraying paints, dyes or the like, is shown in a simplified and partial manner in figure 3 where it is indicated overall with 1.

The innovative industrial rotary booth 1 described herein is comparable, albeit with the due, significant and innovative constructional differences which will be highlighted below, to the prior art industrial rotary booth C depicted in the accompanying figures 1 and 2 as well as in the prior art document published with GB2098885 A.

The industrial rotary booth 1 comprises, according to what has already been learned in the state of the art and can be found in part in figure 1 : a supporting load-bearing structure (such as typically a box-like casing) 2 having at least one loading area 3 in which each leather P to be subjected to a spraying treatment, in the various surface dimensions in which it is available on the market, is conducted inside the load-bearing structure 2, and a discharge area 4 (in this case, physically, spatially or constructionally distinct from the loading area 3) in which the just-treated leather P is conducted outside the load-bearing structure 2; a conveyor belt 5, for example formed by parallel and close nylon threads and mainly housed in the load-bearing structure 2, adapted to advance along a linear direction W the leather P housed on an upper face 5a of the conveyor belt 5; a rotating unit 6 - also called "carousel" in the jargon of the tanning sector - coupled inside the load-bearing structure 2 and provided with spraying means overall indicated with 7 and having the function of depositing in nebulized form on the leather P, advancing along the linear direction W on the conveyor belt 5, at least one fluid painting mixture while the spraying means 7 follow a closed annular trajectory T under the rotation of the rotating unit 6, so that the spraying means 7 take a working condition along two primary circumferential arcs 8, 9 belonging to the closed annular trajectory T and defined directly above (or above) the conveyor belt 5, and a resting condition along two secondary circumferential arcs 10, 11 , connected to each other by the primary circumferential arcs 8, 9 and belonging to the closed annular trajectory T, defined externally and laterally to the conveyor belt 5; suction means, overall numbered with 13, operatively connected to the load- bearing structure 2 and adapted to capture by means of an airflow at least the fumes produced by the spraying treatment inside the load-bearing structure 2. According to the invention, the suction means 13 suck directly at the spraying area and in the lower part of the load-bearing structure 2 and are distributed according to an arcuate configuration substantially superimposable and equal to an arcuate spatial distribution of the primary circumference arcs 8, 9 (belonging to the closed annular trajectory T) along which the spraying means 7 take the working condition in which they dispense the fluid painting mixture on the leather P advancing on the conveyor belt 5.

The suction means 13 are of the type known per se to the person skilled in the art, for example comprising one or more fans, not depicted in the following figures, which maintain the flow in the rotary booth 1 and can be positioned on the top of the booth 1 itself or on external units connected to the booth 1 with appropriate air conveying channels.

In a particular and advantageous manner, although not essential, the suction means 13 are arranged at the same and constant distance from the spraying means 7 themselves and suck when the spraying means 7 take the aforesaid working condition.

Furthermore, the suction means 13 suck below:

• the primary circumference arcs 8, 9 of the spraying means 7;

• the transverse encumbrance of the conveyor belt 5 measured according to a width direction orthogonal to the linear direction W of advancement of the leather P arranged on the upper face 5a of the conveyor belt 5 itself.

Even more in particular, as diagrammed in figure 5, the suction means 13 communicate by means of an air channeling system with the lower area 2a of the load-bearing structure 2, below the conveyor belt 5 and in which, as known, the fumes Q produced by the spraying treatment of the leathers P most accumulate, in order to put such a lower zone 2a in depression and thus allow a greater suction efficiency of such fumes Q.

Preferably but not necessarily, the suction means 13 communicate directly, but only in this specific case, with a storage tank 14 arranged inside the load-bearing structure 2 and below the conveyor belt 5, adapted to receive by falling the particulate L and the fumes Q produced by the spraying treatment performed by the spraying means 7 on the leather P.

Figure 3 highlights that the rotary booth 1 of the invention further comprises a collection plane 12, contained inside the load-bearing structure 2 and arranged below the spraying means 7 and the conveyor belt 5 and provided with an upper face 12c, adapted to receive by falling at least the particulate (or the residue or the residual particles) L of the fluid painting mixture used during the spraying treatment of the leathers P. In a particular and innovative manner, the collection plane 12 is also provided with a convex profile 12’ along two opposite side edges 12a, 12b which, as can be better understood from figure 4, correspond in projection (or in height), to the primary circumference arcs 8, 9 of the closed annular trajectory T followed by the spraying means 7 when the rotating unit 6 rotates, preferably around a vertical linear axis Y (and, for example, according to the direction given by the arrow J in figure 3).

Also, this constructional expedient linked to the curved profile 12’ of the collection plane 12 at the two side edges 12a, 12b directly below, in vertical projection, the primary circumference arcs 8, 9 (also called spraying arcs) contributes to optimizing and rationalizing the airflow of the suction means 12 inside the rotary booth 1 of the invention, sensitively improving it with respect to what occurs in the equivalent rotary booths of the known type.

In fact, the particular combination of the system of cooperation of the suction means 13 with the spraying means 7 with the arcuate shape of the two side edges 12a, 12b of the collection plane 12 allows a uniform suction along the entire spraying path avoiding unevenness in the application path of the painting mixture due to the movement of the particulate dispersion flame L, benefitting a greater cleaning of the environment circumscribed by the load-bearing structure 2 of the rotary booth 1 of the invention with respect to that of the similar rotary booths of the prior art.

Figures 3 and 4 show that the opposite side edges 12a, 12b along which the collection plane 12 has the aforesaid convex (or curved or arcuate) profile 12’ are contained in the transverse dimension, orthogonal to the linear direction W, of the conveyor belt 5.

Advantageously, in order to better achieve the preset objects of the invention, each of the opposite side edges 12a, 12b of the collection plane 12 has a radius of curvature K substantially equal to the radius of curvature of the primary circumference arcs 8, 9 of the closed annular trajectory T travelled by the spraying means 7.

Preferably but not bindingly, in order to limit the overall dimensions of the rotary booth 1 of the invention and, by way of reference, to safeguard space in the factory, the profile 12’ of the collection plane 12 is linear at two opposite side joints 12d, 12e of the collection plane 12 itself connecting the opposite side edges 12a, 12b to each other and being below the secondary circumferential arcs (or non spraying arcs) 10, 11 of the closed annular trajectory T travelled by the spraying means 7 during a normal processing cycle, when the rotating unit 6 rotates around the vertical axis Y: such a constructive detail is best seen in figure 3.

In particular, the opposite side joints 12d, 12e of the collection plane 12 are appropriately although not necessarily arranged laterally external to the conveyor belt 5, in particular, from symmetrically opposite parts with respect to the longitudinal axis X of the conveyor belt 5 and along a longitudinal direction orthogonal to the linear direction W.

According to the preferred embodiment of the invention described herein, the collection plane 12 is arranged according to a pair of inclined planes 15, 16 of an acute angle a with respect to a horizontal reference plane 17 (diagrammed with a drawing end line in figure 5), diverging downwards from opposite parts starting from a common transverse central axis Z, so that the collection plane 12 also becomes a sliding plane which conveys the particulate L produced by the spraying treatment of the leathers P downwards, in particular towards the storage tank 14, in this specific example in the description.

In fact, in the constructional solution of the rotary booth 1 of the invention referred to in figures 3-5, the collection plane 12 is operatively connected to a hydraulic system, not indicated, which creates a constant layer of water on the upper face 12c, facing below the conveyor belt 5, of the collection plane 12: such a layer of water is used to continuously capture and dispose, downwards, the particulate L of fluid painting mixture dispensed by the spraying means 7 which falls by gravity on the collection plane 12 without affecting the leather P.

Consequently, in this specific embodiment described, the storage tank 14 receives by falling the water D coming from the collection plane 12 and dragging therewith the particulate L of the fluid painting mixture, as shown in figure 5.

In this case, the particular combination of the cooperation system of the suction means 13 with the spraying means 7 with the arcuate shape of the two side edges 12a, 12b of the collection plane 12 also allows limiting the swirling of the water collected in the accumulation tank 14, which greatly contributes to or improves the cleaning conditions within the space defined by the load-bearing structure 2 of the rotary booth 1 of the invention.

It is understood that in other embodiments of the rotary booth of the invention, not shown below, the collection plane can be arranged according to a single plane which is inclined with respect to a horizontal reference plane, while maintaining a curved profile at the two opposite side edges lying directly and only below the conveyor belt.

As far as the closed annular trajectory T travelled by the spraying means 7 is concerned, in this specific example it has a substantially circumferential profile in plan view, so that the rotary booth 1 of figures 3 and 4 can be defined as circular. However, other embodiments of the rotary booth for treating leathers by spraying of the present invention, not accompanied by reference drawings, could provide that the closed annular trajectory presents a substantially ellipse-shaped profile in plan.

In the latter case, in particular, the radius of curvature of the primary circumference arcs will be greater with respect to the radius of curvature of the secondary circumference arcs.

Furthermore, always in the case where the profile of the closed annular trajectory is substantially elliptical, the origin of the radius of curvature of the primary circumference arcs lies on the minor semi-axis of the ellipse where it coincides with a point distinct from the center of the ellipse itself, so that the length of the radius of curvature of the primary circumference arcs is greater than the minor semi-axis of the ellipse.

For its part, the origin of the radius of curvature of the secondary circumference arcs lies on the major semi-axis of the ellipse and coincides substantially with one of the foci of the ellipse itself, so that the length of the radius of curvature of the secondary circumference arcs is less than half of the major semi-axis of the ellipse.

Preferably but not necessarily, the aforementioned radius of curvature K of the primary circumference arcs 8, 9 has a value in the range 0.5÷0.9 times the width of the conveyor belt 5. Particularly, the value of such a radius of curvature K of the primary circumference arcs 8, 9 is equal to 0.7 times the width of the conveyor belt: this specific value is nominal and, basically, allows the rotary booth 1 of the invention to limit the space occupied thereby in factory as much as possible, keeping appropriate constructive features, and to further distinguish from the rotary booths of the prior art.

With regard to the rotating unit 6, it preferably comprises a plurality of load-bearing arms 18 which:

• vary in number according to the operating needs and requests of the customer;

• support the spraying means 7;

• are contained in an inner spraying chamber 19 of the supporting load-bearing structure 2;

• protrude radially downwards, so as to face the conveyor belt 5, from a central distribution shaft 20 coupled to the load-bearing structure 2 and operatively connected to motorization means, indicated as a whole with 21, adapted to rotate it around a linear axis Y which is generally vertical and, in any case, orthogonal to the linear direction W.

Purely preferred but not essential and not limiting, the support arms 18 are provided with adjustment means, not specifically indicated in figures 3 and 4, adapted to vary the length of the support arms 18 in relation to the position of the spraying means 7 in the passage thereof from the primary circumference arcs 8, 9 to the secondary circumference arcs 10, 11 and vice versa while the rotating unit 6 rotates (according to the purely preferred direction given by the arrow J) around the aforesaid vertical linear axis Y defined by the central distribution shaft 20 (which can be inside the load-bearing structure 2, as in this case, or outside, arranged in the upper part of the load-bearing structure itself).

Figure 6 diagrammatically and partially shows a possible embodiment of the invention, in which the rotary booth, indicated overall with 50, differs from the rotary booth 1 described with reference to figures 3-5 firstly by the fact that the collection plane 61 is not inclined with respect to a horizontal reference plane but coincides therewith.

In such a case, the collection plane 61 underlying the conveyor belt 54 comprises restraint means, not specifically shown, of the particulate L of the fluid painting mixture sprayed by the spraying means, overall numbered with 56, and comprising for example one or more filtering bodies (coplanar and side by side or superimposed on each other, if more than one) or one or more filtering sheets (coplanar or superimposed on each other, if more than one).

Another significant technical feature differentiating the rotary booth 50 from the rotary booth 1 of the invention (both of which fall within the main object of the invention, as expressed by the appended claim 1) concerns the storage tank 63 with which the suction means, overall indicated with 62, communicate and which, in this case, mainly receives by suction the fumes Q and the particulate L coming from the collection plane 61 without providing any conveyor water veil.

Based on the description just provided, it is therefore understood that the rotary booth for treating tannery leathers by spraying of the present invention achieves the purposes and reaches the advantages mentioned above.

The load-bearing structure of the rotary booth of the invention extends according to a length, measured according to the preset linear advancement direction of each of the leathers on the conveyor belt, rather limited, not exceeding substantially 4 meters.

By its part, furthermore, the rotating unit (or carousel) extends in width, measured according to a longitudinal direction parallel to the transverse central axis Z previously defined and orthogonal to the aforesaid linear direction W of advancement of each of the leathers on the conveyor belt, having a value dependent on the value of the radius of curvature of the primary circumference arcs of the closed annular trajectory T.

Upon execution, changes could be made to the rotary industrial booth for spray treating leathers of the current invention, consisting, for example, of a different type of spraying means with respect to that one described above, although only in relation to the preferred embodiment of the rotary booth exclusively claimed herein.

Furthermore, there could be other embodiments of the rotary booth for treating tannery leathers by spraying as an exclusive claim, however not accompanied by explanatory reference drawings, in which the load-bearing structure has a different constructional concept than that visible in the accompanying drawings, for example a box-like structure in any case of an open type, which does not affect the advantage provided by the present invention.

In addition, it should be noted that in certain embodiments (especially where the space in the factory is quite small) of the rotary booth of the invention, not shown, the loading station and the discharge station can also constructively coincide.

Finally, it is apparent that several other variants may be made to the rotary cabin for treating tannery leathers by spraying in question, within the scope of the appended claims, just as it is apparent that any materials, shapes and sizes of the details shown may be used as needed in the practical implementation of the invention, and may be replaced by other technically equivalent elements.

Where the constructional features and techniques cited in the successive claims are followed by reference signs or numerals, such reference signs were introduced for the sole purpose of increasing the intelligibility of the claims themselves, and therefore such reference signs have no limiting effect on the interpretation of each element identified by way of example only by such reference signs.