Container for spraying a coating product, rotary spray device with such a tray and method for cleaning such a spray device

Description

[0001] The invention relates to a coating product spray bowl, to a rotary projector including such a bowl, as well as to a method of cleaning such a projector.

[0002] In the field of spraying coating products, electrostatically or purely pneumatically, it is known to rotate a bowl of a rotary sprayer and feed it with coating product, to the point that droplets of coating product detach from a spray edge of this bowl and form a cloud from this edge and which can be directed towards an object to be coated such as, for example, a motor vehicle body. With this type of equipment, it is known to use a flow of air for guiding the cloud of droplets, commonly called skirt air or shaping air, in order to direct or shape the cloud of droplets towards the object to be coated.

[0003] In this type of application, it is necessary to clean the headlight regularly, especially when changing the coating product, for example to adapt it to the color intended for a vehicle.

[0004] This issue is not limited to automotive coating facilities. It also concerns coating facilities for other industrial products.

[0005] In this context, it is known to use three separate rinsing systems, each with a dedicated cleaning product supply system, these three systems comprising an injector channel and, possibly, a ring for rinsing the internal radial surface of the bowl, a channel for rinsing the exterior of the bowl and, finally, an external rinsing box provided for cleaning a front face of the body of the projector into which air ejection orifices for shaping the cloud of droplets open.

[0006] Such a rinse box is complex to design and manufacture. Its use increases the time required to change the coating product, as well as the operating cost of a coating product projection installation since this rinse box must be installed, supplied with cleaning product and maintained in a specific manner.

[0007] Various techniques have been considered for cleaning internal and external parts of a bowl of a rotary coating product sprayer, as is apparent from EP-A-0 715 896, EP-A-0 951 942, EP-A-1 426 113, US-B-6 578 779, EP-A-2 464 459, EP-A-0 878 238, US-B-6 569 258, US-B-6 341 734, EP-A-3 046 675, EP-A-0 785 032, US-A-5 813 708, US-B-8 840 043, JP-A-2013 000611, JP-A-H10 99731 and JP-A-2002 186883. These documents do not concern themselves with the rinsing of the front face of the projector body, into which the guide air ejection holes open.

[0008] US-B-6,569,258 proposes cleaning guide air ejection orifices by supplying a solvent through these orifices themselves. The cleaning is effective, but this approach induces a long drying time for the multiple small supply channels of these air ejection orifices. Indeed, at the end of the cleaning operation, these channels must be carefully dried, in order to ensure that no drop of cleaning product is projected onto an object being coated, which would harm the quality of the application.

[0009] On the other hand, the bowl of the first embodiment of US-A-2017 / 128969 comprises a shoulder provided at the outlet of a cleaning channel, which has the effect of directing a cleaning product, radially to the axis of rotation, towards an internal surface of a body of a projector in which this bowl is mounted, then towards the front of the projector. The bowl of the second embodiment comprises an external radial surface that is cylindrical on the rear and frustoconical on the front. The coating product is guided, by the junction between these cylindrical and frustoconical surfaces, to take a frustoconical shape and to flow forward. These different bowls do not make it possible to clean a crown of the body of the sprayer into which air ejection orifices open. This crown must therefore be cleaned by specific means.

[0010] It is these problems that the invention more particularly intends to remedy by proposing a new bowl for a rotating coating product projector which facilitates the cleaning of this projector, to the point that this cleaning can be carried out both efficiently and quickly, without the use of additional equipment, such as a rinsing box.

[0011] To this end, the invention relates to a coating product spray bowl intended to be integrated into a rotary coating product sprayer, this sprayer comprising a turbine for driving the bowl in rotation about an axis of rotation and a body which defines the axis of rotation and which comprises shaping air ejection orifices arranged in a crown, the bowl comprising a body centered on an axis and which defines an internal radial surface for distributing the coating product up to a spraying edge, as well as an external radial surface. According to the invention, a deflector, integral with the bowl, is arranged on the external radial surface of the bowl and returns, at least partially towards the crown of the body, a flow of cleaning product which circulates along this external radial surface, in the direction of the spraying edge.

[0012] Thanks to the invention, the deflector makes it possible to return cleaning product to the crown of the body into which the air ejection orifices open, which makes it possible to clean this crown of any deposits of coating product which have formed there, in a particularly simple, rapid and effective manner. Thus, the front face of a projector equipped with a bowl according to the invention can be cleaned effectively

[0013] According to advantageous but not mandatory aspects of the invention, such a projector may incorporate one or more of the following features: The deflector forms an angular break zone of the outer radial surface. The deflector defines, in a plane radial to the axis of rotation and with the outer radial surface upstream of the deflector, a dihedral with an apex angle of between 10° and 170°, preferably between 45° and 135°. The deflector is located, along the outer radial surface, at a non-zero distance from the spray edge, this distance preferably being greater than 5 mm, more preferably greater than 10 mm. The deflector is equipped with channels for guiding the flow of cleaning product towards the crown. The channels are arranged through the deflector. Alternatively, the channels are notches arranged on a surface of the deflector. The channels are inclined in an ortho-radial direction relative to the axis of rotation.

[0014] According to another aspect, the invention relates to a rotary coating product sprayer comprising a bowl rotating about an axis of rotation, a turbine for driving the bowl to rotate about the axis of rotation, a body which defines the axis of rotation and which comprises air ejection orifices for shaping a cloud of droplets of coating product discharged from the spraying edge of the bowl, these orifices being arranged on a crown of the body. According to the invention, the bowl is as mentioned above.

[0015] Advantageously, it can be provided that: the deflector is located, along the axis of rotation and in the direction of flow of the coating product towards the edge of the bowl, upstream of the orthogonal projection of the crown on the axis of rotation. The deflector is located, along the axis of rotation and in the direction of flow of the coating product towards the edge of the bowl, downstream of the orthogonal projection of the crown on the axis of rotation. The crown forms the front face of the body and is generally perpendicular to the axis of rotation.

[0016] According to a third aspect, the invention relates to a method of cleaning a rotary coating product projector as mentioned above, which method comprises at least steps consisting of: a) directing a flow of cleaning product towards the outer radial surface of the bowl, while the latter is rotating; and b) allowing the cleaning product to flow at least up to the level of the deflector and, at least partially, towards the crown of the body of this projector.

[0017] Advantageously, step b) comprises two sub-steps b1) and b2), namely: a first sub-step b1) during which the ejection orifices are not supplied with pressurized air; and a second sub-step b2) during which the ejection orifices are supplied with pressurized air.

[0018] The invention will be better understood and other advantages thereof will appear more clearly in the light of the following description of several embodiments of a rotary coating product projector in accordance with its principle, which incorporates a bowl in accordance with the invention, and of a method of cleaning such a projector, given solely by way of example and with reference to the appended drawings in which: there figure 1 is a partial longitudinal section of a principle of a coating projector according to a first embodiment of the invention, incorporating a bowl according to the invention; the figure 2 is a larger scale view of detail III at the figure 1 , during a first step of cleaning this projector; the figure 3 is a detail view similar to the figure 2 during a second cleaning step; the figure 4 is a detail view similar to the figure 2 allowing certain geometric aspects of the invention to be identified; the figure 5 is a view analogous to the figure 2 , but on a smaller scale, allowing us to identify other geometric aspects of the invention. figure 6 is a view analogous to the figure 5 for a projector which does not conform to the invention and the figure 7 is a view analogous to the figure 5 for a projector according to a second embodiment of the invention.

[0019] Projector 2, a front part of which is shown in section in figures 1 à 5 comprises a turbine 4 for driving a bowl 6 in rotation around an axis X8 defined by a body 8 of the projector 2.

[0020] The projector 2 can be of the electrostatic or non-electrostatic type.

[0021] The bowl 6 is supplied with coating product by an axial duct 10 centered on the axis X8 and which opens into a hub 62 of the bowl 6. The bowl comprises a single-piece body 60 which defines an internal radial surface 61 and an external radial surface 65, relative to a central axis X6 of this bowl, which coincides with the axis X8 when the bowl 6 is mounted on the turbine 4. The bowl 6 is equipped with a distributor 64 which makes it possible to return the coating product coming from the duct 10 towards the internal radial surface 61 on which this product is distributed and the downstream end of which constitutes a spraying edge 63 of a cloud N of droplets of coating product, during operation of the projector 2. The function of the surface 61 is to distribute the coating product coming from the duct 10, in a regular manner and with a decreasing thickness along the axis X8, approaching the spray edge 63.

[0022] Along the X6 axis, surface 65 also extends to edge 63.

[0023] Surfaces 61 and 65 and edge 63 are centered on the X6 axis.

[0024] We note D63 the diameter of the spray edge 63.

[0025] In this description, upstream corresponds to a direction facing the source of the coating product or cleaning product, on the left of the figures 1 à 7 , while downstream corresponds to an opposite direction, facing the spray edge 63, on the right of these figures.

[0026] The rotational connection between the rotor 42 of the turbine 4 and the bowl 6 can take place by magnetic attraction, in particular by means of a magnet 47 integrated into this rotor and a ferromagnetic ring 67 integrated into the bowl 6, at the level of its external radial surface 65. As a variant, other means of rotational connection between the rotor 42 and the bowl 6 can be implemented, for example means of connection by screwing.

[0027] The body 8 is provided with skirt air ejection orifices 82 intended to guide or shape the cloud N of droplets of coating product leaving the edge 63 in the direction of an object to be coated, not shown. figure 1 , the air jets exiting the orifices 82 are represented by the arrows F1. In practice, the orifices 82 are regularly distributed around the axis X8, with an angular difference of between 2 and 15°.

[0028] The orifices 82 are supplied with pressurized air by conduits 84 arranged in a part 86 of the body 2 which is most often called the “skirt”.

[0029] The orifices 82 open onto an annular surface of the body 2 which forms a crown 88 surrounding the axis X8 and the bowl 6 in the configuration thereof mounted in the projector 2. The crown 88 forms the front face of the body 8, that is to say its end face oriented towards the object to be coated during operation of the projector 2.

[0030] The crown 88 is generally perpendicular to the axis X8, that is to say forms in a plane radial to the axis X8 like that of the figures, an angle of between 80 and 100° with the axis X8.

[0031] The problem that the present invention more particularly solves concerns the cleaning of this crown 88, particularly when changing the coating product.

[0032] A deflector 66 is provided on the external radial surface 65 of the bowl 6, this deflector 66 being arranged to return, that is to say direct, in the direction of the crown 88, at least part of a flow of cleaning product which circulates on the surface 65.

[0033] In the example of the figures 1 à 5 , the deflector 66 is in one piece with the bowl 6 and can be produced by machining the external radial surface 65.

[0034] The deflector extends continuously over the entire periphery of the external radial surface 65, that is to say all around the body 60.

[0035] The deflector 66 forms an angular rupture zone of the external radial surface 65, that is to say a zone in which this surface changes orientation, abruptly, relative to the axis X6.

[0036] Thus, when it is necessary to clean the external radial surface 65 of the bowl 6, a quantity of cleaning product can be directed towards this surface, as represented by the arrows F2 at figure 2 The flow of cleaning product thus created is distributed over the surface 65, progressing towards the edge 63, until it meets the deflector 66 which modifies its direction of flow by returning it towards the crown 88, which is represented by the arrows F4 at figure 2 .

[0037] The portions of the external radial surface 65 located upstream and downstream of the deflector 66, in the direction of flow of the cleaning product towards the edge 63, are denoted respectively 652 and 654. The downstream portion 654 is arranged between the deflector 66 and the spray edge 63, along the axis X6. The length of this portion 654, measured parallel to this surface in a plane radial to the axis X6, is denoted d6. This length corresponds to the distance between the deflector 66 and the edge 63. This distance is measured between the downstream end of the deflector 66 and the edge 63. This distance is non-zero, preferably greater than or equal to 5 mm, more preferably greater than 10 mm.

[0038] Arranging the deflector 66 on the surface 65, more particularly in an intermediate zone close to the crown 88, makes it possible to use the liquid product provided for cleaning the surface 65 in order to also clean the annular surface formed by the crown 88.

[0039] Thus, the cleaning of the projector 2 comprises, in addition to the conventional steps of cleaning the internal radial surface 61 by injecting cleaning product via the conduit 10, a first step represented by the arrows F2 and consisting of directing the flow of cleaning product towards the upstream portion 652 of the external radial surface 65 of the bowl 6, while the latter is rotated by the turbine 4, around the axes X6 and X8 combined. This first step is already known for certain projectors in which the external radial surface of the bowl is cleaned. This method comprises an additional step during which the cleaning product is allowed to flow over the portion 652 up to the level of the deflector 66, at the point where it is then deflected or redirected towards the crown 88, which is represented by the arrows F4.

[0040] This second step is advantageously broken down into two sub-steps respectively represented in figures 2 And 3.

[0041] In the first sub-step, the orifices 82 are not supplied with pressurized air. This allows the flow of cleaning product deflected by the deflector 66 to effectively clean the entire crown 88, including the portion 882 of this crown located radially outside the orifices 82.

[0042] In the second sub-step represented in the figure 3 , the orifices 82 are supplied with pressurized air, to the point that jets of pressurized air emerge from these orifices 82, as represented by the arrow F1, which has the effect of pushing back the flow of cleaning product towards the downstream portion 654 of the surface 65, as represented by the arrow F6.

[0043] Thus, complete cleaning of the surface 65 can be obtained, both upstream of the deflector 66, on the surface portion 652 and downstream of the latter, on the surface portion 654.

[0044] As is more particularly evident from the figure 4 , with the deflector 66 is arranged, axially along the axis X8, downstream of the projection P88 of the surface 88 on this axis. In other words, the deflector 66 is arranged downstream of the orifices 82, along the axis X8.

[0045] Alternatively, and as shown in dot-and-dash lines in the figure 4 , with the deflector 66', this can be arranged upstream of the orifices 82.

[0046] According to another variant, which is not shown, the deflector 86 can be aligned, along the axis X8, with the orifices 82.

[0047] In radial section, the deflector 66 has a generally triangular shape, with two slightly concave surfaces, as seen in figure 3 .

[0048] The upstream and downstream surfaces of the deflector 6 are noted respectively 662 and 664, that is to say the surfaces facing respectively towards the surface portion 652 and towards the surface portion 654, that is to say respectively towards the turbine 4 and towards the spraying edge 63 in the mounted configuration of the bowl 6 in the projector 2.

[0049] We note Δ65 a straight line tangent to the surface 65 upstream of the deflector 66 in a plane radial to the axis X6, which is that of the figure 4 . We also note Δ66 a straight line passing, in the same plane, through the base and the top of the surface 662, the base being the junction between the surface 65 and the deflector 66, on the upstream side of this deflector and the top being the external radial edge of the deflector 66. The straight line Δ66 represents the average orientation of the surface 662 in the plane of the figure 4 .

[0050] The lines Δ65 and Δ66 define, in the plane of the figure 3 , a dihedral D whose vertex angle is noted α.

[0051] This angle has a value of the order of 135°.

[0052] Alternatively, and as shown in dotted lines for the alternative embodiment shown schematically in figure 4 , the dihedral D' formed by lines Δ65 and Δ66' can have an acute vertex angle α', i.e. less than 90°.

[0053] In practice, the apex angle α or α' of the dihedral D or D' defined between the upstream surface 662 of the deflector 6 and the external radial surface 65 upstream of this deflector has a value between 10 and 170°, preferably between 45 and 135°.

[0054] We note P66 the junction point between the lines Δ65 and Δ66 defined above. For the alternative embodiment shown on the left of the figure 4 , we can define, in the same way, a point of intersection P66' between the lines Δ65 and Δ66'. The point P66 or P66' represents, in the plane of the figure 4 , a circle-shaped line from which the deflector 66 or 66' acts on the flow of the cleaning product. The deflector 66 or 66' is considered to be upstream or downstream of the crown 88 depending on the position of this point P66 or P66' relative to the orthogonal projection P88 of the crown 88 on the axis X8.

[0055] As shown in the figure 5 , this point P66 can be located, along the axis X8, either upstream, like the point P66A, or downstream, like the point P66B, or at the same level, like the point 66B as the orthogonal projection P88 of the crown 88 on this axis X8.

[0056] In the sprayers shown in the figures 5 And 6 , elements similar to those of the first embodiment bear the same references. In the following, only what distinguishes these embodiments from the first embodiment is described.

[0057] In the sprayer mode of the figure 6 , the deflector 66 is provided with channels 666 which each comprise a first branch 666A generally parallel to the portion 652 of the external radial surface 65 of the bowl 5 in the vicinity of the deflector 66 and a portion 666B connected to the portion 666A and directed towards the crown 88.

[0058] Thus, a flow of cleaning product as represented by arrow F2 at figure 6 can penetrate into the various channel portions 666A and be redirected via the channel portions 666B to the crown 88 which can thus be effectively cleaned. On the figure 6 , arrow F4 shows the path of the cleaning product inside the deflector 66 and its change of direction within a channel 666.

[0059] In the second embodiment shown in the figure 7 , open channels 666 are formed by notches provided on the upstream surface 662 of the deflector 66, which is defined as in the first embodiment.

[0060] The 666 channels are advantageously regularly distributed around the X6 axis.

[0061] The number and distribution of the 666 channels of the sprayer of the figure 6 and the second embodiment can be chosen depending on the number and distribution of the outlet orifices 82. This is however not obligatory.

[0062] The channels 666 can be characterized by their diameter which in practice is between 0.1 and 3 mm, preferably between 0.5 and 2 mm. If the channels are not of circular section, their largest transverse dimension is between 0.1 and 3 mm, preferably between 0.5 and 2 mm.

[0063] The channels 666 are also characterized by their angular orientation relative to the axis of rotation X8 and by the fact that they may or may not have an ortho-radial component relative to this axis. In other words, the channels 666 are divergent in the direction of the orifices 82 and can impart a vortex movement to the flow F2+F4 of cleaning product.

[0064] As contemplated above, particularly with the geometry of the first and third embodiments, the deflector 66 may be formed by a strip of metal deposited on the surface 65 in the form of a weld or braze bead.

[0065] The invention is described above in the case where all of the flow represented by the arrow F2 is diverted by the deflector 66 towards the crown 88. Alternatively, only a portion of this flow can be directed towards this crown, the remainder of the flow continuing to progress towards the edge 63, which makes it possible to clean in passing the portion 654 of the external radial surface 65 arranged axially between the deflector 66 and the edge 63, independently of the action of the skirt air as envisaged above with reference to the figure 3 .

[0066] Alternatively, the deflector may be locally interrupted to facilitate the flow of cleaning product to the surface portion 654, independent of the action of the shaping air.

[0067] In practice, the surface 65 may be supplied with cleaning product from inside the bowl, through the bowl. The internal volume of the bowl is supplied with cleaning product, close to the deflector 64, and the body 60 is pierced with channels for circulating the cleaning product towards the surface 65. As mentioned above, provision may be made for the supply of cleaning product to open onto the external radial surface 65 of the bowl and be diverted by the deflector 66, as shown in figures 2 And 3 . Alternatively, the supply of cleaning product opens onto the external radial surface 65 of the bowl, enters the channels 666 of the deflector 66 and exits by centrifugal effect, as shown in figures 6 And 7. According to another variant not shown, the supply of cleaning product opens directly into the channels 666 of the deflector 66. Furthermore, it is possible to use the same source of cleaning product to clean the surfaces 61 and 65, by means of two cleaning product supply lines, including the injector 10. As a variant, a restriction may be provided on the path of the cleaning product at the outlet of the injector, so as to limit the flow rate of this product which flows towards the internal radial surface 61, to the point that part of the flow is expelled towards the external radial surface 65 which it thus cleans.

[0068] The embodiments and variations contemplated above may be combined to generate new embodiments of the invention, within the scope of the appended claims.

Claims

1. - A bowl (6) for spraying a coating product, intended to be integrated into a rotary spraying apparatus (2) for a coating product, this spraying apparatus comprising a turbine (4) to drive the bowl about an axis of rotation (X8) and a body (8) that defines the axis of rotation (X8) and which comprises orifices (82) for ejecting shaping air arranged in a crown (88), the bowl comprising a body (60) centered on an axis (X6) and defining an inner radial surface (61) for distributing the coating product to a spraying edge (63) as well as an outer radial surface (65), characterized in that a deflector (66) integral with the bowl (6) is arranged on the outer radial surface (65) of the bowl and deflects (F4), at least partially, towards the crown (88) of the body, a flow (F2) of cleaning product flowing along the outer radial surface, towards the spraying edge (63).

2. - The bowl according to claim 1, characterized in that the deflector (66) forms an angular breaking area of the outer radial surface (65).

3. - The bowl according to one of the preceding claims, characterized in that the deflector (66) defines, in a plane radial to the axis of rotation and with the outer radial surface (65) upstream of the deflector, a dihedral (D, 37) with an angle at the apex (α) between 10° and 170°, preferably between 45° and 135°.

4. The bowl according to one of the preceding claims, characterized in that the deflector (66) is located, along the outer radial surface (65), at a non-zero distance (d6) from the spraying edge (63), this non-zero distance being preferably greater than 5mm, more preferably greater than 10mm.

5. - The bowl according to one of the preceding claims, characterized in that the deflector (66) is equipped with channels (666) for guiding the flow of cleaning product in the direction of the crown (88).

6. - The bowl according to claim 5, characterized in that the channels (666) are arranged through the deflector (66).

7. - The bowl according to claim 5, characterized in that the channels (666) are notches arranged on a surface (662) of the deflector (66).

8. - The bowl according to one of claims 5 to 7, characterized in that the channels (666) are inclined in an ortho-radial direction with respect to the axis of rotation (X8).

9. - A rotary spraying apparatus (2) for a coating product comprising: - a bowl (6) rotating about an axis of rotation (X8); - a turbine (4) for rotating the bowl about the axis of rotation; - a body (8) which defines the axis of rotation (X8) and which comprises orifices (82) for ejecting shaping air for a cloud (N) of droplets of coating product discharged from the spraying edge (63) of the bowl (6), these orifices (82) being arranged on a crown (88) of the body (8), characterized in that the bowl (6) is according to one of the preceding claims.

10. - A spraying apparatus according to the preceding claim, characterized in that the deflector (66) is located, along the axis of rotation (X8) and according to the direction of flow of the coating product towards the edge (63) of the bowl (6), upstream of the orthogonal projection (P88) of the crown (88) on the axis of rotation.

11. - The spraying apparatus according to claim 9, characterized in that the deflector (66) is situated, along the axis of rotation (X8) and in the direction of flow of the coating product towards the edge (63) of the bowl (6), downstream of the orthogonal projection (P88) of the crown (88) on the axis of rotation.

12. - The spraying apparatus according to one of claims 9 to 11, characterized in that the crown (88) forms the front face of the body (8) and is perpendicular overall to the axis of rotation (X8).

13. - A method of cleaning a spraying apparatus (2) according to one of claims 9 to 12, characterized in that it comprises at least steps consisting of: a) directing a flow (F2) of cleaning product towards the outer radial surface (65) of the bowl, while the latter is rotating; and b) allowing the cleaning product to flow (F2) at least up to the level of the deflector (66) and, at least partially, in the direction (F4) of the crown (88) of the body (8) of the spraying apparatus (2). and in that, preferably, step b) comprises: - a first sub-step b1) during which the air ejection orifices (82) are not supplied with pressurized air; and - a second sub-step b2) in which the air ejection ports (82) are supplied with pressurized air.