Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B3/00—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements
  • B05B3/02—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements
  • B05B3/10—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member
  • B05B3/1064—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member the liquid or other fluent material to be sprayed being axially supplied to the rotating member through a hollow rotating shaft
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B3/00—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements
  • B05B3/02—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements
  • B05B3/10—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member
  • B05B3/1007—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member characterised by the rotating member
  • B05B3/1014—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member characterised by the rotating member with a spraying edge, e.g. like a cup or a bell
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B3/00—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements
  • B05B3/02—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements
  • B05B3/10—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member
  • B05B3/1007—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member characterised by the rotating member
  • B05B3/1021—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member characterised by the rotating member with individual passages at its periphery
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B3/00—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements
  • B05B3/02—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements
  • B05B3/10—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member
  • B05B3/1035—Driving means; Parts thereof, e.g. turbine, shaft, bearings
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B3/00—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements
  • B05B3/02—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements
  • B05B3/10—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member
  • B05B3/1035—Driving means; Parts thereof, e.g. turbine, shaft, bearings
  • B05B3/1042—Means for connecting, e.g. reversibly, the rotating spray member to its driving shaft
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B3/00—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements
  • B05B3/02—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements
  • B05B3/10—Spraying or sprinkling apparatus with moving outlet elements or moving deflecting elements with rotating elements discharging over substantially the whole periphery of the rotating member
  • B05B3/1092—Means for supplying shaping gas
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
  • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
  • B05B5/04—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces
  • B05B5/0403—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces characterised by the rotating member
  • B05B5/0407—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces characterised by the rotating member with a spraying edge, e.g. like a cup or a bell
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
  • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
  • B05B5/04—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces
  • B05B5/0403—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces characterised by the rotating member
  • B05B5/0411—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces characterised by the rotating member with individual passages at its periphery
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
  • B05B5/025—Discharge apparatus, e.g. electrostatic spray guns
  • B05B5/04—Discharge apparatus, e.g. electrostatic spray guns characterised by having rotary outlet or deflecting elements, i.e. spraying being also effected by centrifugal forces
  • B05B5/0426—Means for supplying shaping gas
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05B—SPRAYING APPARATUS; ATOMISING APPARATUS; NOZZLES
  • B05B5/00—Electrostatic spraying apparatus; Spraying apparatus with means for charging the spray electrically; Apparatus for spraying liquids or other fluent materials by other electric means
  • B05B5/08—Plant for applying liquids or other fluent materials to objects
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
  • B05D1/00—Processes for applying liquids or other fluent materials
  • B05D1/02—Processes for applying liquids or other fluent materials performed by spraying
  • B05D1/04—Processes for applying liquids or other fluent materials performed by spraying involving the use of an electrostatic field

Definitions

• the present invention relates to a liquid coating product spray bowl, intended for integration into a rotary coating product sprayer.
• the present invention also relates to a rotary sprayer comprising such a bowl, as well as a method for applying the coating product using such a rotary sprayer.
• Such a spray bowl is known, for example, from WO03/074187A1
• Such a bowl can be fitted with notches near its circular spraying edge. These notches help to homogenize and refine the droplets leaving the bowl's circular spraying edge.
• a droplet of coating product leaves the edge of the bowl with kinetic energy that is directly proportional to the bowl's rotational speed.
• the ejection direction of the coating product droplets from the bowl's edge is generally perpendicular to the bowl's axis of rotation.
• the coating product droplets must therefore be directed towards the object to be coated, for example, a car body.
• the bowl allows the paint droplets to be directed towards the object being coated.
• an electrostatic charge applied to the coating product before or after spraying allows the electrostatic effect to be used to direct the coating droplets towards the object.
• a recurring problem with rotary coating product sprayers is that the aim is to increase the yield, i.e. the proportion of coating product actually deposited on the object to be coated, without reducing the quality of the coating layer deposited.
• the invention relates to a liquid coating product spray bowl, intended for integration into a rotary coating product sprayer, comprising a body centered on a longitudinal axis and defining an internal radial surface for distributing the coating product up to a circular spray edge centered on the longitudinal axis and equipped with notches formed in the internal radial distribution surface and regularly distributed around its circumference.
• the linear density of the notches along the circular spray edge is greater than or equal to 4 notches per millimeter, and the opening angle of each notch is less than or equal to 45°.
• the combination of the characteristics of the notching obtained by the notches distributed around the circumference of the circular edge, both in terms of linear density and opening angle, results in a relatively large quantity of coating product being sprayed from the bowl edge with good homogeneity of fine droplets, i.e., droplets of a size suitable for creating a coating layer, even when the bowl's rotation speed is relatively low.
• the notching characteristics mentioned above This goes against the grain practice of those skilled in the art, who tend to use notches with large opening angles, on the order of 90° or more, considering that this allows for the creation of channels with a large cross-section for the flow of coating product within the notches of the bowl.
• the present invention proceeds from an opposite approach, in which the number of notches is substantially increased compared to known bowl notches, while reducing the opening angle of each notch.
• the invention relates to a coating product sprayer comprising a body defining an axis of rotation; a coating product spray bowl rotating about the axis of rotation; a turbine for driving the bowl rotating about the axis of rotation; and an air skirt equipped with shaped air outlet ports.
• the coating product spray bowl is as described above, with its longitudinal axis aligned with the axis of rotation.
• the invention relates to a method of applying liquid coating product using a sprayer as described above, in which the bowl is driven by the turbine, rotating around the axis of rotation, with a rotation speed less than or equal to 40,000 rpm, preferably at 30,000 rpm, and the conforming air outlet orifices are supplied with conforming air at a flow rate between 250 and 500 l/min, preferably between 300 and 450 l/min.
• the sprayer includes means for applying high voltage to the product being applied, and in which the applied high voltage is between 40 and 85 kV, preferably between 45 and 60 kV.
• the product applied according to the process of the invention is a primer or a varnish.
• a rotary sprayer for liquid coating product 2 a front part of which is shown in cross-section at the figure 1 , includes a turbine 4 for driving a spraying element 6, referred to as a bowl in the following, rotating about an axis X8 defined by a body 8 of the sprayer 2.
• Sprayer 2 is of the electrostatic type and includes means for bringing to high voltage a coating product being sprayed with sprayer 2, for example a high-voltage cascade and an electrical link between this cascade and the bowl 6, not shown.
• sprayer 2 is of the non-electrostatic type.
• the bowl 6 is supplied with liquid coating product by an axial conduit 10 centered on the axis X8 and opening into a hub 62 of the bowl 6.
• the bowl comprises a one-piece body 60 that defines an internal radial surface 61 and an external radial surface 65, relative to a longitudinal 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 that directs the coating product from the conduit 10 towards the internal radial surface 61, where it is distributed.
• the downstream end of this internal radial surface forms a circular spray edge 63 that produces a cloud N of coating product droplets during the operation of the sprayer 2.
• the function of the surface 61, which is centered on the longitudinal axis X6, is to distribute the coating product from the conduit 10 in a manner regular and with decreasing thickness along the X6 axis, approaching the circular spray edge 63.
• the surface 65 also extends to the circular spray edge 63.
• the diameter of the circular spray edge 63 is denoted D63.
• the diameter D63 is less than or equal to 80 millimeters (mm), for example, approximately 65 mm in the embodiment shown in the figures. "Approximately 65 mm” means 65 mm to the nearest 1 mm. This relatively modest value for the diameter D63 ensures that, for a given rotational speed of the bowl 6, the tangential velocity of the coating product droplets is not too high, thus allowing good control of the droplet distribution in the cloud N.
• the bowl 6, in particular its body 60 is made of aluminum-based alloy.
• the bowl can be made of titanium or a titanium-based alloy.
• Other materials are also possible for bowl 6, for example a magnesium alloy, a non-metallic material such as thermoplastic, thermosetting plastic, or ceramic.
• upstream refers to a direction facing the source of the coating product or cleaning product sprayed when the sprayer 2 is operating, on the left side of the figure 1 , while downstream corresponds to an opposite direction, turned towards the circular spray edge 63, on the right of this figure.
• the rotational locking 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.
• the body 8 is equipped with an air skirt 86 which defines conforming air ejection orifices 82 intended to guide or conform the cloud N of coating product droplets leaving the edge 63 towards an object to be coated (not shown).
• figure 1 The air jets exiting the orifices 82 are represented by the arrows F1.
• the orifices 82 are regularly distributed around the axis X8, with an angular deviation between 2 and 15°.
• the orifices 82 are supplied with pressurized air through conduits 84 provided in the air skirt 86.
• the orifices 82 open onto an annular surface of the body 2 which forms a ring 88 surrounding the axis X8 and the bowl 6 in its mounted configuration in the sprayer 2.
• the ring 88 forms the front face of the body 8, that is to say its extreme face oriented towards the object to be coated during the operation of the sprayer 2.
• the circular spray edge 63 is equipped, on its inner side facing the longitudinal axis X66, with a serration 66 formed by a succession of notches 661 , 662 , 663 ... 66i ... which are regularly distributed around the axis X6.
• the serration 66 is formed in the portion of the distribution surface 61 which joins the edge 63.
• 66i designates one of the notches of the serration 66.
• the notches 66 i are identical to each other, over the entire circumference of the edge 63.
• the notching 66 is shown on only part of the figure, on the right, in order to visualize the distribution surface 61, on the left. In practice, the notching extends over the entire circumference of the circular spray edge 63.
• All the notches 66i of the serration 66 are straight, parallel to the X6 axis, and parallel to each other. According to a non-shown embodiment of the invention, the notches 66i are not parallel to the X6 axis, but all have the same angle of inclination with respect to the X6 axis and are parallel to each other. Thus, in all cases, the serration 66 does not constitute a knurling formed by the intersection of notches oriented in different directions. The dimensions of the serration 66 are easier to control than if it were a knurling.
• e 63 be the minimum radial thickness of the circular spray edge 63, measured between the bottom of a notch 66 i and the external radial surface 65.
• the thickness e 63 is measured radially to the longitudinal axis X6.
• This minimum radial thickness e 63 is chosen to be between 0.2 and 0.5 mm, preferably between 0.3 and 0.4 mm. In the example in the figures, this radial thickness e 63 is equal to 0.35 mm.
• the radial thickness e 63 ensures good geometric stability of the bowl 6, even when subjected to relatively high centrifugal forces when the turbine 4 rotates the bowl 6 around the X6 and X8 axes.
• the radial thickness e 63 therefore guarantees the dimensional stability of the serrations 66, and thus the homogeneity and regularity of the paint droplets leaving the circular spray edge 63, even in the event of variations in the rotational speed of the bowl 6.
• L63 of the circular spray edge 63 is equal to this diameter minus twice the radial thickness e63 and multiplied by ⁇ .
• L 63 D 63 ⁇ 2 * e 63 * ⁇
• the length L63 of the circular spray edge 63 is approximately 204 mm.
• the number of notches 66 i of the notching 66 is 1200.
• the linear density DL 66 of the notches 66 i along the circular pulverization edge 63 is defined as the number of notches 66 i of the notching 66 per millimeter of circumference of the edge 63.
• the linear density DL 66 of the notches 66 i of the notching 64 can be controlled by varying the number of notches 66 i of this notching 66 and the diameter D63 of the edge 63, over a range of spray bowls, while respecting the condition DL 66 ⁇ 4 notches/mm.
• An opening angle ⁇ 66 of a notch 66 i is defined as the angle formed between two plane surfaces constituting the sides of this notch 66 i .
• the notches 66 i being identical over the entire circumference of the edge 63, the angle ⁇ 66 is constant over this circumference.
• the surfaces forming the sides of the notches 66 i are not planar.
• the opening angle ⁇ 66 of a notch is defined as an average angle between these surfaces.
• the angle ⁇ 66 is approximately 20°, that is, 20° to within 0.5°. This value of the angle ⁇ 66 allows the notches 66 i to be implanted with a high linear density, which makes it possible to distribute the coating product from the edge 63 with a flow rate sufficient to ensure effective coating with the bowl 6.
• the angle ⁇ 66 can have a value greater than 20°, while remaining less than or equal to 45°, preferably less than or equal to 30°.
• the radial depth of a notch 66 i is variable over its length, taken parallel to the longitudinal axis X6.
• p 66 a maximum depth of a notch 66 i of the notching 66, this depth being measured perpendicular to the longitudinal axis X66.
• This maximum depth (p. 66) is chosen to be greater than or equal to 0.1 mm, preferably greater than or equal to 0.2 mm. This maximum depth (p. 66) gives each notch a sufficient volume to accommodate, during application, a quantity of coating product necessary to produce the N cloud.
• the geometry of the notches 66i is compatible with the application of coating products under industrial conditions, since the linear density DL66 of the notches 66i of the notching 66 , distributed along the circular spray edge 63, allows for the distribution of a relatively high flow rate of coating product, even though the opening angle ⁇ 66 of these notches 66i is relatively small.
• the invention contradicts standard reasoning for those skilled in the art, which would tend to increase the opening angle ⁇ 66 to allow for the distribution of a higher flow rate of coating product at the circular spray edge 63, in order to create the droplet cloud N.
• the serration structure 66 of the bowl 6 mentioned above allows it to be used in a coating application process in which the bowl 6 is driven by the turbine 4, rotating about the axes X6 and X8, at a relatively low rotational speed of 40,000 revolutions per minute (rpm) or less, preferably 30,000 rpm. This ensures that the coating droplets leaving the circular spray edge 63 have moderate kinetic energy. In this case, the aerodynamic force due to the conforming air and, where applicable, the electrostatic force due to the electrostatic field, allow the paint droplets to be more effectively directed towards the part to be coated.
• the air outlets 82 are advantageously supplied with conforming air at a flow rate of between 250 and 500 liters per minute (l/min), preferably between 300 and 450 l/min.
• the supply flow rate to the outlets 82 can also be expressed in normal liters per minute (NI/min), with values close to those mentioned above.
• NI/min normal liters per minute
• the cascade or any other means of applying a high voltage to the coating product being sprayed is capable of applying a high voltage of between 40 and 85 kilovolts (kV), preferably between 45 and 60 kV since the distance between the circular spraying edge 63 of the bowl 6 and the surface to be coated is reduced, for example less than or equal to 180 mm, preferably less than or equal to 150 mm and advantageously less than or equal to 100 mm.
• kV kilovolts
• the coating product sprayed with the bowl 6 in the application process of the invention is a primer or a varnish.
• the composition of a primer or a varnish is not disrupted by passing through a notch such as the notching 66, whereas this might be the case for a base.
• the homogeneity and size of the cloud of droplets leaving the edge of the bowl 6 after passing through a notch such as notching 66, during the application of a primer or varnish, is not degraded, even at relatively low rotational speed, whereas this might be the case for a base.

Landscapes

• Nozzles (AREA)
• Electrostatic Spraying Apparatus (AREA)
• Application Of Or Painting With Fluid Materials (AREA)
• Spray Control Apparatus (AREA)

Applications Claiming Priority (1)

Publications (1)

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ID=92543247

Family Applications (1)

Country Status (6)

Citations (5)

• 2024
  • 2024-05-28 FR FR2405459A patent/FR3162646A1/fr active Pending
• 2025
  • 2025-05-26 KR KR1020250068398A patent/KR20250170526A/ko active Pending
  • 2025-05-26 JP JP2025086864A patent/JP2025179825A/ja active Pending
  • 2025-05-27 CN CN202510686138.XA patent/CN121016979A/zh active Pending
  • 2025-05-27 EP EP25179006.9A patent/EP4656296A1/de active Pending
  • 2025-05-28 US US19/220,353 patent/US20250367685A1/en active Pending

Patent Citations (5)

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