FR3009795A1 - MACHINE AND METHOD FOR FLUID BARRIER COATING - Google Patents

Abstract

Fluidic barrier coating machine and method The invention relates to a coating machine (1) designed to coat with a coating an article (2) formed mainly by a tannery element or a textile element, the machine (1) comprising: - a coating chamber ( 3) provided with at least one access opening (4) through which the article (2) can be introduced into, and / or removed from, said coating chamber (3), - projection means ( 5) designed to project the coating on said article (2) in order to coat it inside said coating chamber (3), characterized in that it comprises emission means (6) for a flow of fluid arranged to form a fluidic barrier (7) covering at least the majority of said at least one access opening (4) for separating the interior and exterior of said chamber; tannery.

Description

The present invention relates to the general technical field of machines and processes for coating tannery articles and textile articles, in particular by spraying a liquid substance intended to form a coating enabling for example to protect and / or color said articles. The present invention more particularly relates to a coating machine designed to coat with a coating an article formed mainly by a tannery element or a textile element, the machine comprising: a coating chamber provided with at least one opening of access through which the article can be introduced into, and / or removed from, said coating chamber, projection means adapted to project the coating onto said article to coat the article within said chamber coating. The invention also relates to a coating method for coating with a coating an article formed mainly by a tannery element or a textile element, said article being coated inside a coating chamber provided with at least one an access opening through which the article can be introduced into, and / or removed from, said coating chamber. An industrial coating machine is known for coating tannery articles by spraying a color coating thereon with a mobile sprayer, and having a coating chamber provided with a front wall in which is provided an inlet opening, and an opposite wall substantially parallel to the front wall, in which is formed an outlet opening. Through the inlet and outlet openings circulates a rectilinear conveying surface, for example in the form of a treadmill, and on which tannery articles are arranged. The conveying surface is adapted to drive the articles to be coated inside the coating chamber through the inlet opening so that they are coated in said coating chamber, and B13772 / FR is designed for driving the coated articles outside said coating chamber through the outlet opening. Continuous spraying of the coating on the tanning articles causes pollution of the air inside the coating chamber, in particular by suspended coating particles or volatile solvents initially contained in the coating, so that that the indoor air is harmful and polluting and that it is desirable that it is not in contact with the external environment of the machine. However, the inlet and outlet openings of the coating chamber must be sufficiently wide to allow the entry and exit of the conveying surface and the tanning articles in and out of the chamber. coating, which inadvertently allows the polluted air to escape from the coating chamber to the outside, so for example to affect the quality of the air of the workshop in which the machine is installed. In order to limit the passage of polluted air through the inlet and outlet openings, it could be envisaged to occlude said openings by means of removable flaps when an article is being coated at the same time. inside the room. Such a solution, however, has the major disadvantage of limiting the rate of coating of the machine, the need for closing and opening flaps being likely to affect the speed of movement of the articles and the conveyor. This solution also proves inefficient due to the simple need to open the shutters, which lets out polluted air. The known coating machine is therefore provided with openings of rectangular shapes both wide enough to allow the passage of the conveying surface and articles to be coated (the latter being generally flat), and nevertheless narrow to limit the passage of polluted air outside. This coating machine is also provided with a polluted air extraction device disposed on a side wall of the coating chamber, and designed to suck the polluted air through the side wall in order to reject it by a chimney located for example in height, or leading to the outside of the workshop. The suction of the polluted air induces an intake of unpolluted outside air into the coating chamber through the inlet and outlet openings, this admission creating a current substantially opposing any reflux of polluted air to the outside. Such an operation, while it generally makes it possible to minimize the pollution of the immediate periphery of the machine, has the disadvantage of depriving the interior space of the workshop of a large quantity of air, the quality of which is generally adapted to the environment. personnel, for the users of the machine, and even for the operation of tools and machines. This air with particular qualities is wasted, the coating machine absorbing it through its inlet and outlet openings to mix it with polluted air from inside the coating chamber, then finally reject it to outside the building. In addition, the operation of such a machine may have the adverse effect, for example, to cool the workshop in winter evacuating to the outside of the air that has been heated for the convenience of users. Similarly, in summer, air conditioning around the machine is wasted as it passes through the machine and spreads outward. This may lead to more extensive use of heating or cooling equipment in the workshop and, of course, lead to adverse environmental and economic consequences. In addition, according to this scheme of operation, the polluted air of the machine is released into the atmosphere directly outside the workshop, particularly harmful to the environment and the health of people in the area. proximity. It is also necessary that the flow of air admitted through the inlet and outlet openings is large enough to prevent any leakage of polluted air into the workshop, which on the one hand considerably limits the size of the inlet and outlet openings and secondly requires relatively large air extraction means, 25 mainly increasing the energy consumption of the machine, the noise emitted by said air extraction means, and the cost of general maintenance of the installation. B13772 / FR The objects assigned to the invention are therefore intended to remedy the various disadvantages mentioned above and to propose a new machine and a new coating process to significantly limit the polluting leaks outside the machine while not consuming the air located in the immediate environment of said machine. Another object of the invention is to propose a new coating machine and a new coating process to limit polluting leakage outside the machine with high efficiency. Another object of the invention is to provide a novel coating machine and a novel coating method for coating articles to be coated at a high rate and / or during continuous production. Another object of the invention is to propose respectively a new coating machine and a new coating process whose design is simple and whose implementation is easy. Another object of the invention is to propose a new coating machine and a new coating process, the placement of which occupies a small space. Another object of the invention is to propose a new coating machine and a new low cost coating process. Another object of the invention is to provide a new coating machine and a new coating process requiring little maintenance and whose energy consumption is low. Another object of the invention is to propose a new coating machine and a new coating process to reduce the impact of the coating on the environment. B13772 / FR The objects assigned to the invention are achieved by means of a coating machine designed to coat with a coating an article formed mainly by a tannery element or a textile element, the machine comprising: a chamber coating material provided with at least one access opening through which the article can be introduced into, and removed from, said coating chamber; - projection means for projecting the coating onto said article so as to to coat it inside said coating chamber, characterized in that it comprises means for emitting a fluid flow 10 arranged so as to form a fluid barrier covering at least the majority of said at least one access opening for separating the interior and exterior of said coating chamber at said at least one access opening. The objects assigned to the invention are also achieved by means of a coating process for coating with a coating an article formed mainly by a tannery element or a textile element, said article being coated inside. a coating chamber provided with at least one access opening through which the article can be introduced into, and removed from, said coating chamber, characterized by separating the interior from outside the coating chamber at said at least one access opening by the emission of a fluidic fluid-forming fluid stream covering at least a majority of said at least one access opening . Other features and advantages of the invention will appear and will appear in more detail on reading the description given below, with reference to the accompanying drawings, given solely by way of illustrative and non-limiting example, in which: Figure 1 shows, in a schematic front view, a coating machine according to the invention. - Figure 2 shows a schematic sectional view of Figure 1 along a plane A-A '. B13772 / FR - Figure 3 illustrates in a schematic sectional view of Figure 1 along the plane AA 'a detail of Figure 2. The coating machine 1 according to the invention and illustrated in the figures is designed to partially or completely covering an article 2 to be coated with a coating, and is designed to be preferably integrated within an industrial production line, or at least a mechanized process of transformation of article 2. The machine 1 according to the invention is specifically designed to cover an article 2 to be coated which is predominantly, and preferably integrally, formed by a tannery element, such as a leather or a skin, or alternatively by a textile element, such as A fabric, or fabric, produced from an assembly of fibers or yarns, woven or not. As non-limiting examples, article 2 can be in the form of a garment, an article of leather goods, booty, furnishing, an object constituted at least on the surface of an element tannery or a textile element such as an automobile seat. Article 2 can also be in the form of a simple skin, a simple leather, or a simple raw fabric, not integrated in a manufactured product, as illustrated in FIG. article 2 to be coated is preferably flat in the image of a skin, comparable to a two-dimensional article 2, or on the contrary volumic in the image of an article of leather goods or furniture, comparable to an article three-dimensional. Preferably, the machine 1 is specifically designed to coat substantially flat tanneries. The machine 1 according to the invention shown in the figures comprises a coating chamber 3, and can thus be presented as a coating booth, inside which the article 2 is intended to be coated. Preferably, the coating chamber 3 comprises at least one ceiling 22 and vertical walls 23 forming an outer envelope 11 of the coating chamber 3 of generally parallelepipedal shape, optionally provided with observation windows 24 formed in said walls. vertical 23, through which a user can control the smooth running of the coating of said article 2. B13772 / FR According to the invention, the machine 1 comprises projection means 5 designed to project the coating on the article 2 in order to The coating coating is thus designed and formulated to be projected onto the article 2 by projection means 5 of the machine 1, for example in the form of a mobile sprayer. The coating is therefore designed to be sprayed or sprayed, in this case in liquid, pasty or powder form, in the direction of said and on said article 2, in order to coat the latter, that is to say to coat last of a thin layer, such as a film, which is preferably substantially uniform, continuous and homogeneous. The coating is deposited and fixed on the article 2 to its impact against it, its final fixing may require such a drying or polymerization, for example in a drying tunnel. Article 2 can also be coated temporarily without departing from the scope of the invention. The coating may be adapted to color the article 2 at the surface or depth, and may be for example in the form of a paint or varnish liquid or powder, or a dye. The coating may also, cumulatively or not with its coloring properties, be adapted to protect the article 2 from external aggression by covering it, and may be for example in the form of a varnish, a waterproofing paint or a protective surface treatment of article 2, and be visible or not when deposited on said article 2. Of course, the invention is not limited to only these types of coatings given as examples illustrative and not exhaustive. The outer casing 11 substantially prevents any deposit of coating on the outside of the machine 1, so as not to soil or soil the direct environment of the machine 1 with accidental projections of coating, or coating particles in suspension. Since the coating of the coating is also capable of generating fumes (for example of solvent, or fine particles in suspension) which may be harmful, harmful and / or polluting, the outer casing 11 makes it possible to isolate the interior of the chamber 3 to limit and confine the coating projection. Within the meaning of the invention, "polluted air" 21 designates the air located inside the coating chamber 3 is therefore "stale" or "polluted" in particular by these B13772 / FR emanations, as opposed to the surrounding air 19, the composition of which is totally or partially free of said fumes, and is thus cleaner, less polluted or even unpolluted. Within the meaning of the invention, the "surrounding air" 19 designates an air zone located outside the machine 1, in the immediate periphery thereof. By "outside air" 18 is meant an air zone situated further away from the machine 1 than the surrounding air 19, for example in another room of the building, outside the building, or sufficiently outside the building. distance of not being in direct contact with the machine 1. The coating chamber 3 furthermore makes it possible to protect the coating of the article 2 from the external environment of the machine 1, and makes it possible, for example, to avoid depositing and fixing foreign bodies (such as dust) on the article 2 before, during or after its coating, especially when the coating is not dry. According to the invention, the coating chamber 3 is provided with at least one access opening 4 through which the article 2 can be introduced into, and / or removed from, said coating chamber 3. From preferably, said at least one access opening 4 is sufficiently wide to allow the passage of the article 2 from the outside to the inside and / or vice versa. Nevertheless, said at least one access opening 4 is preferably as narrow as possible so that the coating remains isolated inside the coating chamber 3. As shown in FIG. access opening 4 preferably forms a rectangle whose height is less than the width, to allow the passage of a flat article 2 such as a skin, a leather or a fabric. The machine 1 may comprise a single access opening 4 allowing the introduction or the extraction (or both) of the article 2 of the coating chamber 3. The machine 1 shown in FIGS. 2 and 3 comprises, according to a preferred embodiment of the invention, two access openings 4, one said inlet opening 4A through which the article 2 can be introduced into the coating chamber 3, the other said opening 4A through which the article 2 can be removed from the coating chamber 3. The inlet opening 4A and the outlet opening 4B are preferably formed in the vertical walls 23 of the chamber. coating 3, preferably respectively in a vertical wall 20A and an outlet wall 20B opposite and B13772 / FR the outer casing 11, and are of generally rectangular shape. Such an arrangement advantageously makes it possible to integrate the machine 1 with a production line, in association for example with a cutting machine located upstream near the inlet opening 4A and with a drying tunnel disposed downstream of the machine 1 near the exit opening 4B. According to an important characteristic of the invention, the machine 1 comprises means 6 for transmitting a fluid flow Ff arranged so as to form a fluidic barrier 7 covering at least the majority of said at least one access opening 4 to separate the interior and exterior of said coating chamber 3 at said at least one access opening 4, the fluid flow Ff is in the form of a fluid stream, or a continuous fluid movement, the displacement of the fluidic particles for diverting or driving the polluted air 21 and the surrounding air 19, for example away from said at least one access opening 4, so that said Ff fluid flow impedes the passage of polluted air 21 and surrounding air 19. The fluidic barrier 7 thus removes polluted air 21 from the surrounding air 19 so that they do not enter little or no contact with each other, so that they do not mix sensibly not. The fluid flow Ff may be laminar or turbulent, pulsed or constant emitted, rectilinearly or multidirectionally, but is preferably formed by a monodirectional flow with abundant and regular flow, forming an effective physical barrier to isolate the inside the coating chamber 3 from the outside of said coating chamber 3. Preferably, the flow of fluid Ff is a flow of air emitted so as to form a curtain of air, the air being a inexpensive fluid, non-flammable, and easy to implement.

However, it will also be possible to envisage a fluid of a different nature for particular uses such as a neutral gas (for example in the case where the air would be caused to react in a detrimental manner with the coating coating or article 2) or liquid such as water or oil (which may have absorbent properties to achieve an increased barrier effect). Thus, all or part of the open surfaces formed by the at least one access opening 4 (preferably the inlet opening 4A and the outlet opening 4B) are occluded by a curtain of fluid forming the fluidic barrier 7 which, while being advantageously penetrable by article 2, makes it possible to retain on the one hand the majority or all of the polluted air 21 inside the coating chamber 3, and on the other hand the majority or all of the foreign bodies outside said coating chamber 3. The coating chamber 3 is thus made substantially impervious to any entry and exit of fluid or gas through its main openings formed by said at least one access opening 4, while allowing the entry and exit of the article 2 through them. Preferably, said at least one access opening 4 is delimited by an edge 25, the fluid flow Ff being emitted from a first portion of the edge 25, said transmission portion 12, towards a second portion of the edge 25 said receiving portion 13, the transmission portion 12 being located opposite the receiving portion 13, so that said fluid flow Ff adopts a one-way trajectory and covers substantially all of the In the preferred case where said at least one access opening 4 is rectangular as shown in the figures, the emission portion 12 is one of the long sides of the rectangle (preferably the portion upper edge 25), the receiving portion 13 being the second large side (preferably the lower portion of the edge 25), the fluid flow Ff covering all of said at least one access opening 4 to form an air gap circulating (preferably from the top down), connecting the first to the second long side, in the open surface of said at least one access opening 4. The emission means 6 may be formed for example by a series of nozzles fed with fluid under pressure and disposed along the edge 25 of said at least one access opening 4. However, in the case of the coating machine 1 shown in the figures according to a preferred embodiment of the invention, the coating chamber 3 comprises an outer casing 11 in the thickness of which is provided said at least one access opening 4, so that the emission portion 12 forms a surface S corresponding to the thickness (that is to say, to the wafer) of the outer casing 11, the fluid emission means 12 being arranged along the surface S and in the form of a groove, a plurality of orifices, or a gate, through which the fluid is emitted. As illustrated in FIGS. 2 and 3, the surface S is preferably elusive and perpendicular to the outer wall of the outer casing 11 and extends over the entire perimeter of the access opening 4. The throat is placed in the direction of the length of said at least one access opening 4, that is to say perpendicular to the passage of the article 2, and halfway between the outside and the inside of the chamber of coating 3, so that the air flow Ff is emitted parallel to the outer casing 11 (preferably parallel to the vertical wall 23), and strikes the receiving portion 13 so as to separate into two veins, one internal, the other external.

Thus, a first part of the air of said air flow Ff is directed towards the inside of said coating chamber 3 and forms the inner vein, and a second part outside and forms the outer vein. Alternatively, the receiving portion 13 may be provided with a throat-shaped manifold of similar shape to the emission groove, or one or more receivers for receiving all or part of the air flow Ff emitted and evacuate, for example, polluted air 21 carried by the latter. Preferably, the outer casing 11 comprises a framework 14 comprising hollow structural members 15 designed to ensure the transport of the fluid and the supply of the fluid emission means 6, in particular in the case where these means are directly formed in the surface S, and is in the form of a groove, a plurality of orifices, or a gate, through which the fluid is emitted. The hollow structural elements 15 are thus in the form of hollow tubes, or hollow beams making it possible both to contribute to forming the framework and I or the walls of the coating chamber 3, and to ensure the transport fluid forming a network of channels for conveying said fluid from the fluid source to the emitting means 6. As shown in the figures, a portion of the hollow frame members 15 can thus form the frame of the observation window 24, located above said at least one access opening 4 whose surface S forms the bottom of the frame. In the case where the receiving portion 13 is provided with a manifold, it can be connected to hollow frame members 15 so that the recovered fluid is conveyed to an evacuation location. B13772 / FR Preferably, the coating machine 1 comprises an external air intake device 18 designed jointly to: provide a first portion of the outside air 18 to the emission means 6 to form the air flow , preferably via the hollow frame members 15, - introducing a second part of the outside air 18 into the coating chamber 3. The admission device 16 may comprise an inlet chimney 26, shown FIGS being located on the roof 27 of the machine 1, and comprise a device for setting in motion, constituted by a pump, a compressor or a fan for sucking the outside air 18 located at the entrance of the chimney intake 26, to supply outside air 18 (possibly pressurized and / or heated) both the emission means 6 described above, and the coating chamber 3. Preferably, the chamber coating 3 is powered by the i through grids formed in the ceiling 22 of said coating chamber 3, and connected to the inlet duct 26 by ducts forming the roof 27 of the machine 1, whose interior is hollow and sloping (as illustrated in Figure 1) so that the entire surface of the grids is fed substantially equivalent flux and constant.

The outside air 18 can thus be advantageously taken away from the machine 1, for example outside the workshop in which said machine 1 is placed (the inlet chimney 26 can be connected to the roof of the workshop ). It is therefore important to differentiate the outside air 18 from the surrounding air 19, the latter being located in the immediate environment of said machine 1, and in particular at the height of said at least one access opening 4. In fact, the machine 1 is preferably designed not to use said surrounding air 19 during its operation. However, without departing from the scope of the invention, the machine 1 may, on the contrary, be designed to use the surrounding air 19 as outside air 18. Preferably, the coating machine 1 also comprises an extraction device 17A and 17B filtration designed to filter and discharge the indoor air, that is to say B13772 / FR polluted air 21, the coating chamber 3 to the outside of said machine 1, and designed to operate in conjunction with the external air intake device 18 to create an air flow within said coating chamber 3. In such a configuration, the outside air 18 is introduced into the interior of the chamber. coating chamber 3 so as to push and / or mix with polluted air 21, to drive it to the filter device 17B (placed for example behind a grid of one of the vertical walls 23, such as 'illustrated in the figures), through which the polluted air 21 is n and a significant part of its polluting or harmful particles. Any known and adapted filter can be used, such as a paper filter, water curtain, etc. or a combination of filters. The filtered air 28 is then discharged from the machine 1 at the extraction device 17A, for example in the form of a chimney located on the roof 27 of the machine 1, possibly connected for example to the roof of the machine. the workshop in which the machine 1 is located, to evacuate the filtered air 28 outside and to prevent the filtered air 28 from directly invading the surrounding air 19. Preferably, the coating machine 1 comprises a conveying means 8 designed to transport the article 2 between the outside and the inside of said coating chamber 3 through said at least one access opening 4. The conveying means 8 thus allows an automated coating of article 2, which is preferably transported automatically inside the coating chamber 3 to be coated, and then outside thereof after coating. The conveying means 8 can be for example in the form of a movable hook or a movable hanger to which the article 2 is suspended, and designed to convey it inside and outside the coating chamber 3. Preferably, the conveying means 8 is in the form of a movable conveying surface 9 moving through said at least one access opening 4, and designed to drive the article 2 when it is deposited on said conveying surface 9, as shown in the figures. The conveying surface 9, or at least the functional part of said conveying surface 9, thus passes through said at least one access opening B13772 / FR, at the same time as the article 2 resting on said conveying surface 9, and passes through the fluidic barrier 7. Preferably, the fluid flow Ff is emitted so as to pass through said conveying surface 9, which is porous. Therefore, the separation between the inside of the coating chamber 3 and the outside of the machine 1 can suffer from any clearance or space necessary for the circulation of the conveying surface 9, so and can be optimal, the fluid flow Ff being sufficiently undisturbed by the obstacle formed by the conveying surface 9 to pass therethrough. As illustrated in accordance with the preferred embodiment of FIGS. 2 and 3, the flow of fluid Ff can, for example, be continuously emitted from the transmission portion 12 to the receiving portion 13, while the conveying surface 9 passes between said transmitting portions 12 and receiving 13, the space between said conveying surface 9 and the receiving portion 13 being then covered by the fluidic barrier 7 despite the intermediate presence of said conveying surface 9.

Preferably and as shown in the figures, the fluid flow Ff is emitted from top to bottom and substantially perpendicular to the conveying surface 9. In this way, the fluid flow Ff does not apply any tangential force or lifting device able to move or lift the article 2 relative to the conveying surface 9, especially when the article 2 is light and flat, such as a leather or skin. Preferably, the conveying surface 9 is in the form of a conveyor belt formed of a plurality of conveying threads substantially parallel to one another, said conveying threads being belted between at least two drive rollers. 10 so as to be stretched to form the conveying surface 9.

The conveying son thus move in their longitudinal direction (defining a direction of movement D) synchronously with respect to each other, and cross said at least one access opening 4 secant manner, preferably substantially perpendicular. The conveying son, made for example of plastic material, are spaced apart so as to form a virtual surface of which they occupy physically only a sufficiently small proportion to freely pass substantially all of the fluid flow Ff. Nevertheless, the conveying son B13772 / FR are sufficiently close to each other to support and ensure the transport of the article 2, and are spaced apart from each other for example by a distance of between 2 centimeters (cm and 40 cm, preferably 15 cm. In the preferred case where the machine 1 is provided with an inlet opening 4A and an outlet opening 4B, each of them is preferably provided with emission means 6 designed to generate a fluid barrier 7 for each of her. In this preferred case, each of them is crossed by the conveying surface 9, which can thus flow rectilinearly without interruption in the direction of travel D, which goes from the inlet opening 4A to the opening of output 4B, said conveying surface 9 connecting said inlet opening 4A to said outlet opening 4B. The invention also relates to a coating process for coating an article 2 formed mainly by a tannery element or a textile element with a coating, said article 2 being coated inside a coating chamber 3 provided with at least one access opening 4 through which the article 2 can be introduced into, and / or removed from, said coating chamber 3. In this process, the interior is separated from the outside of the the coating chamber 3 at the level of said at least one access opening 4 by the emission of a fluid flow Ff forming a fluidic barrier 7 covering at least the majority of said at least one access opening 4.

Advantageously, the method allows the article 2 to ensure that it does not slow down or slow down article 2 before, during or after it passes through said at least one access opening 4, which notably allows production to take place. continuous, with for example a continuous and uninterrupted displacement of the conveying means 8. Indeed, said at least one access opening 4 remains open to the passage of the article 2 at any time of production, while remaining closed by the fluidic barrier 7 ensuring the physical separation of the inside and the outside of the coating chamber 3. This ensures that the inside of the coating chamber 3 remains separated from the outside permanently, even in the case where the rate of production is high. B13772 / FR Preferably, the article 2 is passed through the at least one access opening 4 without interrupting the emission of the fluid flow Ff, in order to guarantee a permanent seal of the coating chamber 3, in particular in the case of a serial production, where several articles 2 must be coated by the machine 1 in the coating chamber 3, and are brought into and out of said coating chamber 3 at high frequency. The fluidic nature of the fluidic barrier 7 thus permanently allows the passage of the article 2 (and preferably conveying means 8) through itself, while permanently blocking the exchanges between the surrounding air 19 and polluted air 21.

Preferably, when the machine 1 is running, the conveying surface 9 circulates continuously and the fluidic barrier 7 is permanently active jointly with the displacement of said conveying surface 9, and / or the coating of the projection 5. The coating of an article 2 can thus take place in the following manner: - the article 2 is deposited on the conveying surface 9, said conveying surface 9 conveys the article 2 inside the coating chamber 3 passing through the inlet opening 4A, - the article 2 is coated, preferably without interruption of its movement, inside the coating chamber 3, - the surface of Conveying 9 leads the article 2 outside the coating chamber 3 passing through the outlet opening 4B. B13772 / EN

Claims (4)

1 - coating machine (1) designed to coat with a coating an article (2) formed mainly by a tannery element or a textile element, the machine (1) comprising: - a coating chamber (3) provided at least one access opening (4) through which the article (2) can be introduced into and / or removed from said coating chamber (3), projection means (5) designed to projecting the coating on said article (2) so as to coat it inside said coating chamber (3), characterized in that it comprises means for transmitting (6) a flux of fluid arranged to form a fluid barrier (7) covering at least a majority of said at least one access opening (4) for separating the interior and exterior of said coating chamber (3) at the level of said at least one access opening (4). 2 - Apparatus (1) for coating according to claim 1, characterized in that it comprises a conveying means (8) designed to transport said article (2) between the outside and the inside of said coating chamber (3) through said at least one access opening (4). 3 - Apparatus (1) for coating according to claim 2, characterized in that the conveying means (8) is in the form of a movable conveying surface (9) moving through said at least one opening of access (4), and adapted to drive the article (2) when deposited on said conveying surface (9), the fluid flow being emitted so as to pass through said conveying surface (9), which is porous . 4 - Apparatus (1) coating according to claim 3, characterized in that the fluid flow is emitted from top to bottom and substantially perpendicular to the conveying surface (9). Coating machine (1) according to one of Claims 3 to 4, characterized in that the conveying surface (9) is in the form of a treadmill formed of a plurality of conveyor wires substantially parallel to one another, said conveying wires being encircled between at least two drive rollers (10) so as to be stretched to form the conveying surface (9). 6 Machine (1) for coating according to any one of claims 1 to 5, characterized in that said at least one access opening (4) is delimited by an edge (25), the flow of fluid being emitted to from a first portion of the edge (25) said transmission portion (12), towards a second portion of the edge (25) said receiving portion (13), the transmission portion (12) being located opposite the receiving portion (13). 7 - Apparatus (1) for coating according to claim 6, characterized in that the coating chamber (3) comprises an outer casing (11) in the thickness 15 of which is provided said at least one access opening (4), so that the emission portion (12) forms a surface (S) corresponding to the thickness of the outer envelope (11), the fluid emission means (6) being arranged along the the surface (S) and being in the form of a groove, a plurality of orifices, or a grid, through which the fluid is emitted. 8 - Coating machine (1) according to claim 7, characterized in that the outer casing (11) comprises a framework (14) comprising hollow structural elements (15) designed to carry the fluid and supplying the fluid emission means (6). 9 - Apparatus (1) for coating according to any one of claims 1 to 8, characterized in that the fluid flow is a stream of air emitted to form a curtain of air. B13772 / FR 3009 795 19 10 - Coating machine (1) according to claim 9, characterized in that said coating machine (1) comprises an external air intake device (16) designed to together: - supply a first part of the outside air (18) to the emission means (6) 5 to form the air flow, introduce a second part of the outside air (18) into the coating chamber (3). 11 - Apparatus (1) for coating according to claim 10, characterized in that it also comprises an extraction device (17A) and filtration (17B) designed to filter and evacuate the air inside the chamber d coating (3) outwardly of said machine (1), and adapted to operate in conjunction with the external air intake device (16) (18) to create a flow of air within said chamber coating (3). 12 Apparatus (1) for coating according to any one of claims 1 to 11, characterized in that it comprises two access openings, one said inlet opening (4A) through which the article (2) can be introduced into the coating chamber (3), the other said outlet opening (4B) through which the article (2) can be removed from the coating chamber (3). 13 - Apparatus (1) for coating according to at least claims 3, 7 and 12, characterized in that the outer casing (11) of the coating chamber (3) is generally parallelepipedal in shape, the opening of entry (4A) and the outlet opening (4B) being respectively provided in an opposite and an opposite vertical wall (20A) and outlet wall (20B) of said outer casing (11) and being of general shape rectangular, each of them being provided with emission means (6) designed to generate a fluid barrier (7), and being traversed by the conveying surface (9). 14 - Coating process for coating an article (2) formed mainly by a tannery element or a textile element with a coating, said article (2) being coated inside a coating chamber (3) provided with at least one access opening (4) through which the article (2) can be introduced into, and I or 813772 / FRretired from, said coating chamber (3), characterized in that separates the interior of the outside of the coating chamber (3) at said at least one access opening (4) by the emission of a fluid flow forming a fluidic barrier (7) covering at minus the majority of said at least one access opening (4). 15 - Coating process according to claim 14, characterized in that the article (2) is passed through the at least one access opening (4) without interrupting the emission of the fluid stream. B13772 / EN