Cartridge for an injection module, multi-component injection module comprising such a cartridge and coating product sprayer comprising such a module

Abstract

The present invention relates to a cartridge (40) for a multi-component product injection module of a coating product sprayer, this cartridge being configured to be installed at the head of the sprayer, forming a static mixer and defining, within a rigid mixing body (402), a mixing path (T1) for the multi-component product, equipped with fluid mixing baffles (410) for feeding an injector (42) of the multi-component product injection module (30). The baffles (410) and the mixing body (402) are one-piece. The multi-component product mixing path (T1) is helical in shape. A helical flow path (T2) for cleaning fluid is defined within the mixing body (402). The helix of the mixing path (T1) of multi-component product and the helix of the flow path (T2) of cleaning liquid are nested within the mixing body (402).

Description

[0001] The present invention relates to a cartridge for a multi-component product injection module, as well as a multi-component product injection module for a coating product sprayer, which includes such a cartridge. The invention also relates to a multi-component coating product sprayer comprising such a module.

[0002] In the field of coating spraying, the use of multi-component, particularly two-component, coating products is common. For the purposes of this invention, a multi-component coating product comprises at least two components. By way of non-limiting example, some two-component products are obtained by mixing a water-soluble paint and a solvent-based hardener, these two components being only slightly miscible.

[0003] To ensure the homogeneity of a multi-component coating product, it is known to use an injection module that incorporates a cartridge forming a static mixer and defining a mixing path equipped with baffles. This mixing path allows for the intimate bonding of the coating product components.

[0004] Such static mixers are known as EP3446776A, WO2019 / 014181A, WO2017 / 151305A, WO2017 / 027279A, WO2021 / 094278A, US2023 / 032382A, US476657A, DE102014017032A, WO2021 / 108245A and WO2017 / 005354 A.

[0005] In these known materials, baffles are housed within channels that define the mixing path. Despite careful attention to fitting the baffles within the channels, gaps remain between the baffles and the channels. These gaps allow some of one or more components of the multi-component coating product to leak through, potentially leading to inhomogeneities in the mixture. Furthermore, rinsing the mixing path, which must be performed when changing the coating's color, may be incomplete due to these gaps.

[0006] It is these drawbacks that the invention intends to remedy in particular by proposing a new cartridge for a multi-component product injection module, particularly effective in terms of mixing and cleaning, which limits the risks of inhomogeneity of the multi-component coating product at the output of the injection module.

[0007] To this end, the invention relates to a cartridge for a multi-component product injection module of a coating product sprayer. This cartridge forms a static mixer and defines, within a rigid mixing body, a multi-component product mixing path. The cartridge is equipped with fluid mixing baffles for feeding an injector of the multi-component product injection module. The baffles and the mixing body are integral, and the multi-component product mixing path is helical in shape. According to the invention, a helical cleaning fluid flow path is defined within the mixing body. The helix of the multi-component product mixing path and the helix of the cleaning fluid flow path are nested within the mixing body.

[0008] Thanks to the invention, the fact that the baffles and the mixing body are a single unit eliminates any gaps between the baffles and the channels defined by the body. This ensures that all components of the multi-component product being mixed are subjected to the action of the baffles along the entire length of the mixing path. This guarantees that the multi-component coating product is homogeneous at the cartridge outlet, and therefore at the injection module outlet. The interlocking of the flow paths of the multi-component product and the cleaning fluid contributes to the compactness, particularly the axial compactness, of the cartridge, and thus of an injection module comprising the cartridge and a sprayer equipped with this injection module.

[0009] According to advantageous but not mandatory aspects of the invention, such a cartridge may incorporate one or more of the following features: The cartridge is made of synthetic material and manufactured using additive manufacturing. The developed length of the mixing path is strictly greater than the length of the mixing body, measured parallel to a longitudinal axis of the cartridge. The multi-component product mixing path comprises at least two sections with flow directions reversed relative to each other, preferably at least three sections, with the flow directions of two successive sections along the multi-component product mixing path reversed relative to each other.

[0010] According to a second aspect, the invention relates to a multi-component product injection module for coating product sprayer, this injection module comprising an injector and a static mixer formed by a cartridge as described above.

[0011] Advantageously, the injector and cartridge are mounted in an alignment sleeve.

[0012] According to a second aspect, the invention relates to a two-component coating product sprayer comprising a first supply line for a first liquid component, a second supply line for a second liquid component, a spraying element, and a module for injecting a multi-component product into the spraying element. According to the invention, the multi-component product injection module is as described above.

[0013] The invention will be better understood and other advantages thereof will become more apparent in the light of the following description of an embodiment of a coating product injection module and sprayer conforming to its principle, given solely by way of example and with reference to the accompanying drawings in which: [ Fig. 1 ] There figure 1 is a schematic cross-section of a multi-component coating product sprayer according to the invention, incorporating an injection module and a cartridge also according to the invention; [ Fig.2 ] There figure 2 represents, on several inserts A) to E) the injection module of the sprayer of the figure 1 respectively in longitudinal section, end view, exploded perspective, perspective, as well as the cartridge belonging to this injection module, also in perspective; [ Fig.3 ] There figure 3 represents on two inserts A) and B) the cartridge of the injection module of the figure 2 , in side view, highlighting by transparency the paths it defines, as well as in partial view of a multi-component coating product mixing path integrated into this cartridge; and [ Fig.4 ] There figure 4 represents developed views of the mixing path of the multi-component coating product, complete, in perspective and in elevation in inserts A) and B), partial, in perspective and in elevation with local tear-off, in inserts C) and D).

[0014] The sprayer 1 shown in the figure 1 is intended to project a multi-component coating product onto unrepresented objects, for example, motor vehicle bodies.

[0015] This sprayer is intended to be mounted at the end of the arm 2 of a multi-axis robot and includes a main body 4 which defines an axis of rotation X6 for a spraying element, here a bowl 6, driven in rotation by a turbine 8, which is advantageously an air turbine.

[0016] The main body 4 also supports a high voltage unit 10, which allows a high continuous voltage to be applied to the coating product discharged from the edge of the bowl 6, when it rotates around the axis X6.

[0017] The coating product applied by means of the sprayer 1 is a two-component product comprising a water-soluble paint, the flow of which is controlled by a first proportional valve 12, and a hardener, the flow of which is controlled by a second proportional valve 14. The valves 12 and 14 are part of the supply lines to the bowl 6, respectively for paint and hardener, which open into the plane of the figure 1 at the level of these valves.

[0018] A line 16 supplying cleaning product opens into the plane of the figure 1 and extends, for the most part, outside of this plan.

[0019] Supply pipes 18 wound around an auxiliary body 20 of the sprayer 1 supply the turbine 8, the valves 12 and 14 and the line 16, respectively with air, paint, hardener and cleaning product. They are part of the aforementioned supply lines.

[0020] A multi-component product injection module 30 for the bowl 6 is mounted on the main body 4 by means of three screws 32. This injection module is centered on the rotation axis X6. X30 denotes a longitudinal axis of the injection module 30. In the mounted configuration of the injection module 30 on the main body 4, the axes X6 and X30 coincide.

[0021] The injection module 30 comprises a sleeve 34, preferably made of electrically conductive material such as a metal, in the shape of a socket, one piece with a base 36 in which are provided orifices 38 for the passage of the screws 32.

[0022] A cartridge 40, which is part of the injection module 30, is mounted in the casing 34.

[0023] As visible on insert C) of the figure 2 , the cartridge 40 is preferably inserted into the envelope 34, which facilitates the replacement of the cartridge 40 during maintenance operations of the injection module 30.

[0024] However, according to an unrepresented variant of the invention, the cartridge 40 is one piece with the envelope 34.

[0025] The cartridge is configured to be mounted at the top of the sprayer 1, that is, on the side of this sprayer facing the bowl 6.

[0026] In practice, for the purposes of the invention, "at the head" means that an object is mounted in the sprayer 1 by being inserted in the center of the turbine 8, more precisely of a rotor of the turbine, or in the bowl 6. Here, the injection module 30, therefore the cartridge 40, is mounted at the head of the sprayer 1.

[0027] We note X40 a longitudinal axis of the cartridge 40. This longitudinal axis X40 coincides with the axis X30 in the mounted configuration of the cartridge 40 in the envelope 34.

[0028] The injection module 30 also includes an injector 42 and a cleaning product diffuser 44. Seals 46, 48 and 50 ensure the sealing of the flow of the coating product along the injection module 30.

[0029] The sleeve formed by the envelope 34 receives both the cartridge 40 and the injector 42, which it allows to be aligned on the axis X6 of rotation of the bowl 6.

[0030] The cartridge 40 is a spare part of the injection module 30 and can be exchanged during the life of the injection module 30 and the sprayer 1, in particular after a prolonged stop which induces a clumping of the product within it, or when changing the sprayed coating product, if the catalyst / base component pairs are no longer miscible, or when the number of baffles in the cartridge needs to change.

[0031] The cartridge 40 comprises a main body 402 which is rigid and extends longitudinally along the axis X40, and a base 404 disposed at one end of the main body 402, which surrounds this body and which includes a projecting part 406 which extends radially to the axis X40, on one side of the main body 402. The cartridge 40 also includes an end piece 408 provided on the side of the base 404 and on which the seal 46 is mounted.

[0032] Cartridge 40 is a single piece and preferably manufactured by additive manufacturing of a synthetic material such as a polyamide resin. In other words, cartridge 40 is 3D printed from synthetic material, and parts 402, 404, 406, and 408 are single pieces.

[0033] Alternatively, only the main body 402 is monobloc and parts 404, 406 and 408 are attached to it, after it has been produced by additive manufacturing.

[0034] According to another variant, the main body 402 or the entire cartridge 40 is 3D printed from a metallic material. This makes it possible to consider cleaning the cartridge 40 by pyrolysis, particularly if the coating product being mixed solidifies in the main body 402.

[0035] L402 is the axial length of the main body 402 of the cartridge 40, this axial length being measured parallel to the axis X40, therefore to the axis X30 in the mounted configuration of the cartridge 40 in the injection module 30.

[0036] In the mounted configuration of the injection module 30 in the sprayer 1, the nozzle 408 is positioned opposite a mixing chamber 22 in which flows of paint and hardener coming out of valves 12 and 14 respectively meet. Thus, in operation, the injection module 30 is supplied with both paint and hardener, by valves 12 and 14.

[0037] The main body defines a path T1 for mixing the components of the multi-component product. This path, which can also be called the mixing path, extends from bottom to top on insert A) of the figures 2 And 3 .

[0038] This mixing path T1 is helical in shape, centered on the X40 axis, and has a developed length LT1, visible at the figure 4 , which is strictly greater than the length L402, due to the helical nature of the path T1. A ratio LT1 / L402 is therefore strictly greater than 1.

[0039] Advantageously, the LT1 / L402 ratio is greater than or equal to 1.1.

[0040] Preferably, this LT1 / L402 ratio is greater than or equal to 1.5.

[0041] In practice, very satisfactory results, in terms of mixing, have been obtained with an LT1 / L402 ratio greater than or equal to 2.

[0042] Thanks to the fact that the length LT1 is strictly greater than the length L402, the path T1 of mixing the coating product can be long enough to obtain an efficient mixing of the two components of the coating product, within the static mixer formed by the main body 402 of the cartridge 40, without creating an over-length of the cartridge 40 or the injection module 30.

[0043] Thus, the injection module 30 maintains an axial length consistent with industry standards. In particular, its axial length can be equal to, or approximately equal to, that of single-component coating injection modules. Therefore, the sprayer 1 is no more cumbersome than a single-component sprayer, and its trajectory relative to a vehicle body within a coating booth can be determined in the same way as that of a single-component product sprayer.

[0044] The entire mixing path T1 is inclined relative to the longitudinal axis X40, therefore not parallel to this axis, due to the helical nature of this path.

[0045] The mixing path T1 is defined by a conduit C1 which is formed inside the main body 402 and in which baffles 410 are arranged whose function is to intimately mix the components coming respectively from the valves 12 and 14.

[0046] Advantageously, the 410 baffles are propeller or blade shaped.

[0047] Alternatively, other forms of chicanes may be chosen, including those disclosed in the documents mentioned above.

[0048] The baffles 410 are integral with the main body 402, preventing the coating components being mixed from leaking between the baffles and any part of the conduit C1. This ensures efficient mixing of the coating components throughout the entire flow path T1. Specifically, thanks to the integral design of the baffles 410 and the body 402, there are no gaps between the baffles and the body through which any part of one or more of the multi-component coating components could escape. Therefore, the risk of inhomogeneity in the multi-component coating at the outlet of the cartridge 40, and thus at the outlet of the injection module 30, is eliminated. The same applies to the risks of incomplete rinsing, which could occur if a component of the multi-component coating product were to become stuck between the baffles 410 and the conduit C1 defined by the main body 402.

[0049] On inserts B) of the figure 3 and C) and D) of the figure 4 The casing of the C1 duct was particularly removed, in order to facilitate the visualization of the 410 baffles.

[0050] In practice, these baffles are not visible since they are embedded in the mass of the main body 402, which is possible thanks to the additive manufacturing of the main body 402 of the cartridge 40.

[0051] A flow path T2 for the cleaning product is provided in the cartridge 40. This flow path T2 is also helical in shape.

[0052] Advantageously, the two helices of paths T1 and T2 are nested around the longitudinal axis X40, within the mixing body 402, which gives good axial and radial compactness to the body 402.

[0053] The path T2 is formed by a helical conduit C2 whose internal volume is free of baffles or any relief that could impede the flow of the cleaning fluid.

[0054] On the side of its mouth C2A, the conduit C2 extends into the projecting part 106, which allows this mouth to be positioned opposite the outlet of the cleaning product supply line 16, while the mouth C1A of the conduit C1, which is defined in the center of the nozzle 408, is positioned opposite the mixing chamber 22.

[0055] The outlet C1B of the conduit C1 is aligned with the longitudinal axis X40. In the mounted configuration of the cartridge 40 in the injection module 30, with the axes X30 and X40 coinciding, the outlet C1B of the conduit C1 is aligned with the mouth 42A of the injector 42.

[0056] The C2B outlet of the C2 duct is radially offset with respect to the longitudinal axis X40, as visible on insert E) of the figure 2 Furthermore, the outlet C2B of the conduit C2 is arranged to supply one or more longitudinal grooves 422 formed on the external peripheral surface of the injector 42, which allows the diffuser 44 to be supplied with cleaning product.

[0057] The invention is described above and illustrated in the figures in the case where the multi-component product is a two-component product. However, it is applicable with products having more than two components, in which case the number of supply lines and valves of the sprayer 1 is adjusted.

[0058] The technical characteristics of the embodiments and variants mentioned above can be combined with each other, according to any technically permissible combinations.

Claims

1. Cartridge (40) for a multi-component product injection module (30) of a coating product sprayer (1), this cartridge forming a static mixer and defining, within a rigid mixing body (402), a mixing path (T1) for the multi-component product, equipped with fluid mixing baffles (410) for supplying an injector (42) of the multi-component product injection module (30), in which the baffles (410) and the mixing body (402) are monobloc and the multi-component product mixing path (T1) is helical in shape, characterized in that - a helical flow path (T2) of cleaning liquid is defined in the mixing body (402) and - the helix of the mixing path (T1) of multi-component product and the helix of the flow path (T2) of cleaning liquid are nested within the mixing body (402).

2. Cartridge according to claim 1, made of synthetic material and by additive manufacturing.

3. Cartridge according to any one of the preceding claims, wherein a developed length (LT1) of the mixing path (T1) is strictly greater than a length (L402) of the mixing body (402), measured parallel to a longitudinal axis (X40) of the cartridge (40).

4. Multi-component product injection module (30) for coating product sprayer, this injection module comprising an injector (42) and a static mixer formed by a cartridge (40) according to any one of the preceding claims.

5. Injection module according to the preceding claim, in which the injector (42) and the cartridge (40) are mounted in an alignment sleeve (34).

6. Two-component coating product sprayer (1) comprising a first feed line (12) for a first liquid component, a second feed line (14) for a second liquid component, a spraying element (6) and a multi-component product injection module (30) into the spraying element, characterized in that the multi-component product injection module (30) is according to one of claims 4 and 5.

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