EP2139604B1 - Spraying member, spraying device comprising such a member, spraying installation and method of cleaning such a member - Google Patents

Description

The present invention relates to a spraying member for a rotary projector coating product, and a projection device equipped with such a spraying member and a coating product spraying installation incorporating such a device. The invention also relates to a method of cleaning such a spraying member.

Conventional rotating bowl spray is used for application to objects to be coated, such as motor vehicle bodies, primers, first coat and varnishes, with paint rates between 100 and 500cc / min. In order to reduce the investments related to the installation and operation of painting lines, the automobile market tends to reduce their length as well as the number of spraying robots installed on these lines. Thus, the sprayers to be mounted on these robots must be able to spray coating products with high flow rates.

Stack stacks are known from the prior art to increase the spraying rate of liquid products. For example, FR-A-1363681 discloses a liquid product spraying plant consisting of a jet liquid spraying member, at least one rotating spindle rotating member disposed thereunder, and means for varying the amount of product to be dispensed. sprayed dispensed to the rotary spray member, varying the distance between the nozzle and the disk or disks. To overcome the fact that the capacity of the installation is generally limited by the maximum capacity of the spraying member with edge, while the spray nozzle would allow a much greater capacity of work, FR-A-1363681 proposes to use two or more ridge spraying devices.

A technical problem posed by the "multi-bowls" spraying means is the cleaning of the external surface of the internal bowls or bowls, soiled during the spraying where the rotation of the member creates a depression between the bowls which causes the deposition of droplets on an outer surface. This surface is difficult to reach by the solvent during rinsing.

FR-A-2 170 940 discloses a spraying member for spraying two separate products with two separate feed means. Such supply means, however, do not allow to simultaneously feed the two distribution surfaces of the spray member. In addition, the construction of such a spraying member is relatively complex and detrimental to the balance and compactness of this organ.

US-A-5,894,993 discloses a spray member comprising a single internal coating material distribution surface and an annular guide for guiding solvent to clean the outer surface of the spray member. However, the flow of coating material sprayed by such a spraying member is relatively limited because there is only one spray edge.

It is these drawbacks that the invention intends to remedy more particularly by providing a compact and compact multi-bowl spraying device whose geometry is such that the cleaning of the external surface of its internal bowl is facilitated.

To this end, the subject of the invention is a spraying member for a rotary coating product projector, said spraying member comprising at least one external bowl and an internal bowl, each bowl defining a spray edge, an internal surface of distribution and an outer surface the inner bowl is being arranged radially inside the outer bowl, then and in that a volume defined between the inner surface of the outer bowl and the outer surface of the inner bowl has a decreasing thickness between a first value, taken at a cleaning product inlet area in the volume, and a second value, taken at the spray edge of the outer bowl, the spray member being characterized in that comprises central supply means of the internal surfaces of distribution of the bowls.

Thanks to the invention, the volume defined between the inner surface of the outer bowl and the outer surface of the inner bowl has a passage section which narrows in the direction of progression of the cleaning product towards the spraying edge of the bowl. external. Indeed, its thickness, which corresponds to the distance, taken perpendicularly to a median of this volume, between the inner surface of the outer bowl and the outer surface of the inner bowl, allows to control the distribution of the cleaning product in this volume. Under the effect of the centrifugal force, the speed of the product increases between the bowls at the same time as the diameter of the bowls. As a result, the pressure of the product between the bowls tends to decrease as the diameter of the bowls increases, i.e. in the direction of flow of the product. To maintain a sufficient level of pressure of the product to the output of the volume, the passage section is to be reduced, which provides the invention. Thus, it is possible to fill this volume with a cleaning product or with a mixture of cleaning product and air, which allows the cleaning product to lick both the inner surface of the outer bowl and the outer surface of the bowl. internal. The cleaning of these internal and external surfaces is thus optimized. In addition, the central supply means can simultaneously feed the two internal distribution surfaces with a compact and balanced construction of the spray member

• Ces moyens d'alimentation centrale comprennent un répartiteur pourvu d'un orifice aligné sur un axe de symétrie des surfaces internes et externes des bols, cet orifice étant destiné à l'alimentation en produit de revêtement de la surface interne de répartition du bol interne
• Les moyens d'alimentation comprennent un déflecteur monté dans le bol interne en regard d'une partie centrale de la surface interne de la répartition
• Le rapport de la deuxième valeur de l'épaisseur du volume sur la première valeur de cette épaisseur est inférieur à 0,9, de préférence à 0,5, de préférence encore de l'ordre 0,4,
• L'arête de pulvérisation du bol externe est axialement en retrait par rapport à l'arête de pulvérisation du bol interne, d'une distance supérieure à 1 % du diamètre de l'arête de pulvérisation du bol interne.
• Des orifices d'entrée d'air vers le volume précité peuvent être prévus sur le bol externe.

According to advantageous but non-obligatory aspects of the invention, such a spraying member may incorporate one or more of the following features:

• These central supply means comprise a distributor provided with an orifice aligned on an axis of symmetry of the internal and external surfaces of the bowls, this orifice being intended for the supply of coating product of the internal distribution surface of the internal bowl.
• The feed means comprise a deflector mounted in the internal bowl facing a central portion of the internal surface of the distribution.
• The ratio of the second value of the thickness of the volume to the first value of this thickness is less than 0.9, preferably 0.5, more preferably of the order 0.4,
• The spraying edge of the outer bowl is axially recessed relative to the spinner ridge of the inner bowl by a distance greater than 1% of the spinneret diameter of the inner bowl.
• Air inlet ports to the above volume may be provided on the outer bowl.

The invention also relates to a coating product spraying device which comprises a spraying member as mentioned above as well as means for driving this rotating member and means for supplying this member with a coating product. .

In the case where the spraying member comprises a splitter provided with an orifice, as mentioned above, the diameter of this orifice is advantageously less than or equal to the internal diameter of the downstream end of the feed means of the feed product. coating.

The invention also relates to a coating product projection installation which comprises, inter alia, at least one projection device as mentioned above.

Finally, the invention relates to a method of cleaning a spraying member as mentioned above, this method comprising a step of gaving the volume defined between the inner surface of the outer bowl and the outer surface of the inner bowl product cleaning and / or air.

Advantageously, it uses for this gavage a cleaning product or a mixture of cleaning products and foaming air.

• la figure 1 est une coupe longitudinale de principe d'un projecteur de produit de revêtement conforme à l'invention utilisé dans une installation conforme à l'invention et incorporant un organe de pulvérisation conforme à l'invention ;
• la figure 2 est une coupe axiale de l'organe de pulvérisation de la figure 1 ;
• la figure 3 est une vue en perspective, avec arrachement partiel, de l'organe de la figure 2
• la figure 4 est une section selon la ligne IV-IV à la figure 2
• la figure 5 est une vue à plus grande échelle du détail V à la figure 2 et
• la figure 6 est une vue analogue à la figure 5 pour un second mode de réalisation de l'invention.

The invention will be better understood and other advantages thereof will appear more clearly in the light of the description which follows, given solely by way of example and with reference to the appended drawings in which:

• the figure 1 is a longitudinal sectional view of a coating product projector according to the invention used in an installation according to the invention and incorporating a spray member according to the invention;
• the figure 2 is an axial section of the spraying organ of the figure 1 ;
• the figure 3 is a perspective view, partially broken away, of the organ of the figure 2
• the figure 4 is a section along the line IV-IV to the figure 2
• the figure 5 is a larger-scale view of detail V to the figure 2 and
• the figure 6 is a view similar to the figure 5 for a second embodiment of the invention.

The projector P represented at figure 1 is fed with coating material from one or more unrepresented sources and moved, for example with a substantially vertical movement represented by the double arrow F ₁ , facing objects O to be coated within a facility I of coating of these objects. The projector comprises an air turbine of which only the rotor 1 is visible on the figure 1 , this rotor being rotated about an axis X ₁ -X ' ₁ .

A body 2, fixed with respect to the axis X ₁ -X ' ₁ , surrounds the rotor 1 and is itself isolated from the outside by a cover 3. An annular support 4 made of magnetic material, for example stainless steel magnetic, is mounted on the front face 21 of the body 2, this support being provided with an annular groove centered on the axis X ₁ -X ' ₁ and in which is disposed an annular magnet 41. An injector 5 coating product is aligned on the axis X ₁ -X ' ₁ .

A spraying member 10 is mounted on a projector P and forms a frustoconical surface 10A intended to cooperate with a frustoconical surface 1A of the rotor 1 to rotate the spraying member 10 and the rotor 1 in rotation. To guarantee effective support of the surfaces 10A and 1A against each other and a relative immobilization in the manner of a Morse cone, a ring 13 of ferromagnetic material is mounted on the spraying member 10, so that an attraction force F ₂ due to the magnet 41 is exerted on the ring 13, which firmly plates the surfaces 10A and 1A against each other, while an air gap E is formed between the ring 13 and the support 4. It is made here application of the technical education of FR-A-2887472 .

The spraying member 10 comprises two bowls 100 and 200, of different diameters and geometries.

The outer bowl 100 is provided with a spray edge 101, a product distribution surface 102 and an outer surface 103.

The injector 5 brings the liquid product to be sprayed to the bowl 100.

In the bowl 100 is fixed an internal bowl 200, by screwing, with a hub 6. The inner bowl 200 is immobilized on the hub 6 by any appropriate means, for example by gluing. Then, the hub 6 is screwed, thanks to a thread 64, into a threaded portion 104 of the bowl 10. The two bowls 100 and 200 are thus assembled by being removable with respect to one another. A male centering cone is provided on the bowl 200, while a corresponding female centering cone is provided on the bowl 100. This ensures a permanent relative centering of these bowls.

The bowl 200 can be fixed on the bowl 100 by other mechanical means, for example in force.

The hub 6 is provided with pads 61 between which there are openings 62 here in the form of beans, for the passage of the coating product of the injector 5 to the inner surface 102 of the bowl 100.

The bowl 200 is provided with a spray edge 201, a product distribution surface 202 and an outer surface 203.

D ₁₀₁ and D ₂₀₁ denote respectively the diameters of the edges 101 and 201. The value of D ₁₀₁ is slightly greater than that of D ₂₀₁ . More precisely, D ₁₀₁ is greater than X at Y% relative to D201. For example D ₁₀₁ may be 63.5 mm, while D ₂₀₁ is 65 mm.

On the bowl 200 is fixed by screwing a distributor / baffle 7. This distributor 7 could be fixed by other mechanical means. The distributor 7 is provided with pads 71 between which are formed openings 72, here in the form of beans, for the passage of the coating product to the inner surface 202 of the bowl 200.

An insert 8 mounted in the bowl 200 defines an orifice 81 aligned on the central axis X ₁₀ -X _'10 of the member 10 which forms an axis of symmetry of the surfaces 102, 103, 202 and 203.

The insert 8 protrudes from the rear face 206 of the bowl 200 intended to be turned towards the injector 5. The portion 82 of the insert 8, which protrudes with respect to the surface 206 has a convergent inner surface in direction of the ridge 201 and can be considered as a funnel.

Alternatively, as shown in FIG. figure 6 the portion 82 of the insert 8 projecting from the surface 206 may be in the form of "inverted funnel", with a diverging outer surface in the direction of the ridge 201 and a cylindrical inner surface with a circular base.

According to another variant which is not shown, the insert 8 may not protrude from the surface 206.

The three forms of the insert 8 contemplated above make it possible to influence the distribution of the product between the flow paths formed by the surfaces 102 and 202 of the two bowls. Different types of bowls can therefore be provided, with inserts 8 of different geometry.

The edges 101 and 201 are not in the same plane, they are offset axially with respect to each other, the edge 101 being set back relative to the edge 201, in order to avoid as much as possible jets of pulverized product recombine, that is to say, mingle with each other. By "indented" is meant that the edge 101 is further away from the objects O than the edge 201. It is necessary to separate as much as possible the jets of coating product from the edges 101 and 201. Indeed, if the These jets recombine, so the size of the droplets increases, while a uniform spray requires droplets as fine as possible.

For example, the distance d ₁ of withdrawal of the edge 101 with respect to the edge 201 may be 10 millimeters for a bowl whose edge 201 has a diameter of the order of 65 mm. In practice, the distance d ₁ represents more than 1% of the diameter D ₂₀₁ of the edge 201, which ensures a good separation of the product jets without axially lengthening the bowl too much. The greater the shrinkage, the less jets of sprayed product recombine.

The inner surface 102 of the bowl 100 and the outer surface 203 of the bowl 200 define a volume V ₁ between them.

où r₁₀₂ et r₁₀₃ sont respectivement les rayons des surfaces 102 et 203 qui sont circulaires.The difference measured between the two bowls 100 and 200 is perpendicular to a median M between the generatrices of the surfaces 102 and 203, that is to say the thickness of the volume V ₁ . The thickness e is equal to the distance between the inner surface 102 and the outer surface 203. Given the geometry of the surfaces 102 and 203 which are symmetrical with respect to the axis X ₁₀ -X _'10, the thickness ea, for a given position along the axis X ₁₀ -X _'10 , the same value regardless of the angular sector around the axis X ₁₀ -X' ₁₀ in which it is measured, which is visible at the figure 4 where the thickness e is uniform. The thickness e determines the passage section S of the volume V ₁ which has an area equal to: $$\mathrm{S}=\mathrm{\pi }\times \mathrm{e}\times \left({\mathrm{<figure-callout\; id="102"\; label="r"\; filenames="imgf0003.png,imgf0004.png"\; state="\{\{state\}\}">r</figure-callout>}}_{\mathrm{102}}+{\mathrm{<figure-callout\; id="203"\; label="r"\; filenames="imgf0003.png,imgf0004.png"\; state="\{\{state\}\}">r</figure-callout>}}_{\mathrm{203}}\right)$$

where r ₁₀₂ and r ₁₀₃ are respectively the radii of the surfaces 102 and 203 which are circular.

We denote by e ₁ the value of the thickness e measured at the level of the entry zone of the product in the volume V ₁ , at the height of the rear face 63 of the assembly consisting of the bowl 200, of the upper part of the hub. 6 and the distributor 8. Note e ₂ the value of the thickness e measured at the edge 101 of the bowl 100. The thickness e decreases continuously from e ₁ to e ₂ , e ₂ being less than e ₁ . For example e ₁ may be 2 mm while e ₂ is a few tenths of a millimeter.

The decrease of the value of e between the values e ₁ and e ₂ has the effect that the section S of product passage in the volume V ₁ , which is annular as shown in FIG. figure 4 , has an area that decreases between the input area and the output area of this volume.

As a variant, the decrease in the value of the thickness e between the values e ₁ and e ₂ can take place non-continuously, this thickness being able, for example, to be constant over a part of the volume V ₁ .

In practice, the values e ₁ and e ₂ are chosen such that their ratio R = e ₁ / e ₂ is less than 0.9, preferably 0.5. Quite satisfactory results have been obtained with R of the order of 0.4.

During spraying, the spraying member 10 rotates about the axis X ₁ -X ' ₁ . The two bowls 100 and 200 are integral and rotate at the same time, at the same speed. The coating product is fed through the injector 5, taps against the rear face 63 of the assembly consisting of the bowl 200, the upper part of the hub 6 and possibly the projecting portion 82 of the distributor 8, and spreads on the inner surface of the bowl 100, to the spraying edge 101 where the liquid splits into fine droplets. In passing, the turbulence in the volume V ₁ and the depression, created in this volume by the acceleration of the product between the two bowls under the effect of the centrifugal force, cause droplets of coating product which are deposited on and substantially soil the entire surface 203 to the ridge 201.

A fraction of the coating product supplied by the injector 5 continues its path directly into the distributor 8 through the orifice 81. This fraction is defined both by the geometry of the distributor 8, in particular the diameter inside of the orifice 81, and by the flow of coating product. This fraction taps against the rear face 73 of the distributor 7 and spreads on the inner surface of the bowl 200, to the spray edge 201 where the liquid splits into fine droplets.

The diameter D ₈₁ of the orifice 81 is less than or equal to the internal diameter D ₅₁ of the downstream end portion 51 of the injector 5. This has the effect of ensuring that at least part of the product leaving the injector is directed to the volume V ₁ . It is possible to adjust the proportion of coating product directed to the volume V ₁ by varying the ratio R '= D ₅₁ / D ₈₁ .

For the rinsing of the spraying member, air-solvent trains are conveyed by the injector 5, sized with a flow rate for filling the volume V ₁ . The air and solvent trains follow the same paths as the coating product, from the injector 5 to the edges 101 and 201.

The reduction of the gap between the bowls 100 and 200 of e ₁ to e ₂ has the effect of compensating for a decrease in pressure due to the centrifugal force and of slightly compressing the rinsing liquid to allow the force-feeding of the volume V ₁ during rinsing of the spray member, thereby rinsing the surface 102 and the surface 203 at the same time.

Thus, the injection of cleaning product can properly clean not only the inner surfaces 102 and 202, but also the surface 203.

In addition, the air-solvent trains can create a foam, by air dispersion in a liquid, which increases the cleaning efficiency. It is also possible that the cleaning product is itself a foaming product. In this case, the compression effect obtained due to the decrease in the thickness e is exerted on the air bubbles present in the dispersion or in the foaming product, which gives rise to a "scraping" effect of the bubbles. air on surfaces 102 and 203.

The bowl 100 is pierced with a series of orifices 150 which each extend between an inlet 150A located on the surface 103 of the bowl 100 and an outlet 150B located on the surface 102. The orifices 150 are cylindrical, each centered on one axis X ₁₅₀ oblique to the axis X ₁₀ -X _'10 . The orifices 150 make it possible to generate an air intake from the outside towards the volume V ₁ . These holes are easy to achieve because they can be drilled in the bowl 100 before mounting the bowl 200.

The invention has been shown with a spraying member 10 having two bowls. It is also applicable with a stack of three or more successive bowls connected in series ended by mounting a dispenser on the innermost bowl. In this case, volumes V ₁ ,..., V _n-1 may be defined by analogy with the embodiment shown, with different geometries, each volume having a decreasing radial thickness, from its zone of entry to its zone. Release.

The invention has been shown with a spraying member 10 attached to the rotor 1 by magnetic effect. It is also applicable with a spraying member fixed by any other means, in particular screwed.

The invention has been shown with bowls 100 and 200 removable. It is also applicable with an organ whose bowls are not removable, for example monoblocks.

The invention has been represented with a bowl 100 whose edge 101 has a diameter D ₁₀₁ greater than the diameter D ₂₀₁ of the edge 201 of the bowl 200. The invention is however applicable to the case where the diameter D ₁₀₁ is equal to slightly smaller than the diameter D ₂₀₁ , which is possible because of the withdrawal d ₁ of the edge 101 relative to the edge 201.

Claims (11)

1. A spraying member (10) for a rotary sprayer of coating product, said spraying member (10) comprising at least one outer cup (100) and one inner cup (200), each cup defining a spraying edge (101, 201), an inner distribution surface (102, 202) and an outer surface (103, 203), the inner cup (200) being placed radially inside the outer cup (100), while a volume (V₁) defined between the inner surface (102) of the outer cup and the outer surface (203) of the inner cup has a decreasing thickness (e) between a first value (e₁), taken at a zone of inlet for cleaning product into the volume (V₁), and a second value (e₂), taken at the spraying edge (101) of the outer cup (100), the spraying member (10) being characterized in that it comprises central supply means (6, 8) for the inner distribution surfaces (102, 202) of the cups (100, 200).
2. The spraying member as claimed in claim 1, characterized in that the central supply means comprise a distributor (8) provided with an orifice (81) aligned on an axis (X₁₀) of symmetry of the inner surfaces (102, 202) and outer surfaces (103, 203) of the cups (100, 200), this orifice being designed to supply the inner distribution surface (202) of the inner cup (200) with coating product.
3. The spraying member as claimed in one of claims 1 or 2, characterized in that the supply means comprise a deflector (7) mounted in the inner cup (200), facing a central portion of its inner distribution surface (202).
4. The spraying member as claimed in one of the preceding claims, characterized in that the ratio (R) of the second value (e₂) over the first value (e₁) is less than 0.9, preferably less than 0.5, more preferably of the order of 0.4.
5. The spraying member as claimed in one of the preceding claims, characterized in that the spraying edge (101) of the outer cup (100) is axially set back relative to the spraying edge (201) of the inner cup (200) by a distance (d₁) greater than 1% of the diameter (D₂₀₁) of the spraying edge (201) of the inner cup (200).
6. The spraying member as claimed in one of the preceding claims, characterized in that the outer cup (100) is provided with orifices (150) for the inlet of air towards the volume (V₁) defined between the outer surface (203) of the inner cup (200) and the inner surface (102) of the outer cup.
7. A device for spraying coating product comprising a spraying member (10), means (1) for rotating said member and means (5) for supplying coating product to said member , characterized in that said spraying member is as claimed in one of the preceding claims.
8. The spraying device as claimed in claim 7, wherein the spraying member is as claimed in claim 2, characterized in that the diameter (D₈₁) of said orifice (81) is less than or equal to the internal diameter (D₅₁) of the downstream end (51) of the means (5) for supplying coating product.
9. An installation for spraying coating product, characterized in that it comprises at least one spraying device as claimed in one of claims 7 or 8.
10. A method for cleaning a spraying member (10) as claimed in one of claims 1 to 6, characterized in that it comprises a step consisting in completely filling said volume (V₁) with cleaning product and/or with air.
11. The method as claimed in claim 10, characterized in that it consists in using, in order to completely fill said volume (V₁), a cleaning product or a mixture of cleaning product and foaming air.

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