EP1305118B2 - Device for supplying a powdery coating product to a sprayer and spray installation comprising same - Google Patents

Description

The invention relates to a device for supplying powder coating material to a projector and to a pulverulent coating product projection installation comprising, among others, such a device.

In the field of pulverulent coating product projection installations, it is known to supply each projector of an installation with a mixture of coating product and a conveying gas which is most often air. In some installations, a projector must be powered with several types of coating material that are selectively used, depending on the nature of the coating to be produced. Thus, in the case of a coating product projection installation on motor vehicle bodies, it is necessary to provide to paint each body according to the color chosen by the customer.

By FR-A-2,441,435 it is known to converge lines connected to different tanks of powdery product to a distributor in which they are arranged in a cone. The spatial distribution and the number of these lines are imposed by the geometry of the distributor. It is thus necessary to provide different types of dispenser depending on the number of coating products to feed the projector. In addition, complex cleaning systems of different pipes and distributors have to. to be provided.

This device has a size such that it must necessarily be placed at a distance from the projector it feeds, so that the pipe connecting the distributor to the projector must be cleaned at each change of product over a relatively long distance, which increases the quantities of product lost and the time of product change.

JP-A-55-022355 discloses a monobloc collector in which open conduits supplying coating product according to the preamble of claim 1. This common collector can not change according to the number of conduits to be connected. The same is true of the known mixer of US Patent 3,912,235 which falls within the technical field of thermal spraying.

It is these drawbacks that the invention intends to remedy more particularly by proposing a power supply device which makes it possible to power a projector with at least two types of powder coating product, this device being easily adaptable to the number of products to be used. use and can be easily exchanged.

In this spirit, the invention relates to a device for feeding a projector with a powder coating product, this device being according to claim 1.

Thanks to the invention, the modular structure of the device of the invention makes it possible to adapt the number of modules used to the number of different sources of coating product, the common collector being created, as and when the addition of additional modules, by the modules themselves. The modular structure of the device of the invention makes it possible to give it relatively small dimensions allowing its implantation as close as possible to a projector, in particular at the level of an arm of a robot moving the projector facing the objects to be coated. The length of pipe to be cleaned downstream of this device at each change of coating product is short, which is advantageous in terms of amount of product lost and time of product change.

• chaque module comprend au moins une vanne apte à mettre sélectivement en communication une entrée du module, reliée à la source de produit ou de fluide de nettoyage, et le collecteur. Une telle vanne permet de piloter chaque module pour qu'il délivre ou non du produit de revêtement ou du fluide de nettoyage au collecteur commun et qu'il alimente ainsi ou non le projecteur.
• chaque module comprend un conduit reliant une entrée du module à la partie du collecteur formé par ce module alors que le collecteur formé par les différents modules s'étend selon une première direction et que le conduit de chaque module s'étend selon une seconde direction, l'angle entre ces directions, pris selon le sens d'écoulement du produit dans ce conduit et ce collecteur, étant un angle aigu. Cette géométrie des modules autorise une transition aisée de l'écoulement du mélange de gaz d'entraînement et de produit de revêtement entre le conduit et la partie du collecteur formée dans chaque module.
• chaque module comprend un élément de base dans lequel est formée la partie du collecteur et une zone de jonction du collecteur avec un conduit. Chaque module comprend également un élément de connexion définissant l'entrée du conduit et une vanne de commande de l'écoulement du produit dans le conduit, cette vanne étant disposée entre l'élément de base et l'élément de connexion. Chaque module est ainsi formé de deux éléments essentiels et d'une vanne emprisonnée entre ces éléments et protégée de l'extérieur par ceux-ci.

According to advantageous but non-mandatory aspects of the invention, the device incorporates one or more of the following features:

• each module comprises at least one valve able to selectively put in communication an input of the module, connected to the source of product or cleaning fluid, and the collector. Such a valve makes it possible to control each module so that it delivers or not the coating product or the cleaning fluid to the common collector and that it thus feeds or not the projector.
• each module comprises a duct connecting an input of the module to the part of the collector formed by this module while the collector formed by the different modules extends in a first direction and the duct of each module extends in a second direction, the angle between these directions, taken in the direction of flow of the product in this duct and this collector, being an acute angle. This geometry of the modules allows an easy transition of the flow of the mixture of driving gas and coating product between the duct and the portion of the collector formed in each module.
• each module comprises a base element in which is formed the portion of the collector and a junction area of the collector with a conduit. Each module also comprises a connection element defining the duct inlet and a product flow control valve in the duct, this valve being disposed between the base element and the connection element. Each module is thus formed of two essential elements and a valve trapped between these elements and protected from the outside by them.

According to an advantageous embodiment of the invention, at least one of the modules forms a first supply duct of the collector and a second supply duct of a recirculation channel of the coating product, these first and second ducts. extending from a common input of the module. In this embodiment, a circulation of the mixture of driving gas and powder coating material can be continuously maintained up to each module, the mixture of air and powder being directed either to the supply manifold of the projector, either to the recirculation channel. This avoids the transient powder setting and the cleaning of the supply ducts of each module. This embodiment is therefore particularly advantageous with respect to the coating product change time and the minimization of the amounts of product lost during a change. In this case, it can be provided that the first and second ducts are each equipped with a controlled valve capable of allowing and / or interrupting the flow of the coating product in the duct under consideration.

The valves used are advantageously sleeve valves which have the particular advantage of operating without hindrance in a relatively aggressive environment, that is to say in contact with a mixture of air and powder.

The invention also relates to a powder coating product projection installation which comprises at least one projector powered by a device as previously described. Such an installation is economical to manufacture, because of the modular nature of the device, and to exploit, because of the minimization of the quantities of coating product lost and the time of rapid change of color. Such an installation easily adapts to variations in its conditions of use, in particular to the number of coating products that can supply each projector.

• la figure 1 est une représentation schématique, avec arrachements partiels, d'une installation de projection de produit de revêtement conforme à un premier mode de réalisation de l'invention ;
• le figure 2 est une vue en perspective éclatée, avec arrachement d'un module constitutif du dispositif d'alimentation utilisé dans l'installation de la figure 1 ;
• la figure 3 est une vue en perspective éclatée d'une vanne manchon utilisée dans le module de la figure 2 ;
• la figure 4 est une vue de côté du dispositif d'alimentation utilisé dans l'installation de la figure 1 ;
• la figure 5 est une vue analogue à la figure 1 pour une installation conforme à un second mode de réalisation de l'invention et
• la figure 6 est une vue de côté du dispositif d'alimentation utilisé dans l'installation de la figure 5.

The invention will be better understood and other advantages thereof will emerge more clearly in the light of the following description of two coating product supply devices integrated in a projection installation in accordance with its principle, given only by way of example and with reference to the appended drawings in which:

• the figure 1 is a schematic representation, with partial detachments, of a coating product spraying installation according to a first embodiment of the invention;
• the figure 2 is an exploded perspective view, with tearing of a constituent module of the feed device used in the installation of the figure 1 ;
• the figure 3 is an exploded perspective view of a sleeve valve used in the module of the figure 2 ;
• the figure 4 is a side view of the feeding device used in the installation of the figure 1 ;
• the figure 5 is a view similar to the figure 1 for an installation according to a second embodiment of the invention and
• the figure 6 is a side view of the feeding device used in the installation of the figure 5 .

The installation represented at figure 1 comprises a manual type projector 1 for projecting a cloud 2 of a mixture of driving gas and powder coating product onto objects to be coated 3. The projector 1 is of the electrostatic type and is connected to a high voltage unit 4 thanks to a conductive cable 5.

The projector 1 is also supplied with a mixture of driving gas and powder coating product by means of a hose 6 connected to a device 10 for selectively supplying it with one of four products P ₁ , P ₂ , P ₃ and P ₄ respectively contained in four bins B ₁ , B ₂ , B ₃ and B ₄ and pumped by Venturi suction systems V ₁ , V ₂ , V ₃ , V ₄ . The device 10 is connected to each Venturi V ₁ to V ₄ by a pipe T ₁ to T ₄ .

The device 10 comprises four modules 11, 12, 13, 14, the modules 11 and 12 being represented at the figure 1 with one half torn off, while the module 13 is shown with a tear of a quarter and that the module 14 is shown without tearing. The device 10 comprises a fifth module 15 connected to a source S of pressurized air via a pipe T ₅ . The device 10 also includes a head 16 from which extends a connecting element 16a intended to cooperate with the hose 6.

XX 'is the axis of symmetry of the element 16 a . The modules 11 to 15 and the head 16 are juxtaposed along the axis X-X '.

The module 11 comprises a base element 111 in which is formed a channel 112 which extends, in the mounted configuration of the device 10, in the direction of the axis X-X 'passing right through the element 111.

The module 11 also comprises a second member 113 carrying a connecting member 113 with the tube T _1. The internal volume of the element 113 defines, with the element 111, a conduit 114 of generally cylindrical shape and which YY 'is noted the central axis. The conduit 114 extends into the element 111 to a junction zone 115 with the channel 112. In other words, the conduit 114 opens into the channel 112 at the zone 115.

114A is the upstream part of the duct 114 formed in the element 113 and 114B its downstream part formed in the element 111 and ends in the zone 115. A sleeve valve 116 is disposed in the duct 114, both in the parts 114A and 114B. In fact, the valve 116 is disposed between the elements 111 and 113.

The structure of the valve 116 emerges more particularly from the figure 3 . This valve comprises a tubular element 116A pierced with two radial orifices 116B and inside which is disposed an elastic sleeve 116C held in place in the element 116A by two rings 116D. When an air flow must take place in the conduit 114, the sleeve 116C remains pressed against the inner surface of the element 116. When it is necessary to interrupt the circulation in the conduit 114, a control air pressure is applied to the sleeve 116C through the orifices 116B, as represented by the arrow F ₁ at the figure 1 , which has the effect of pinching the sleeve 116C and thus cutting the flow in the duct 114. An orifice 113 b visible at the figure 4 is provided in the element 113 for the supply of control air to the valve 116.

The modules 12, 13 and 14 are identical to the module 11 and each formed of a base element 121, 131 or 141 and a connection element 123, 133 or 143. Each module 12, 13 and 14 also comprises a valve sleeve 126, 136 or 146.

The element 121 defines a channel 122 which is generally aligned with the channel 112, along the X-X 'axis, in the mounted configuration of the device 10. In the same way, the modules 13 and 14 each define a channel 132 , 142 also aligned on the axis XX 'and with an axial passage 162 of the head 16. The elements 112, 122, 132, 142 and 162 thus form a manifold C through which can flow an air / powder mixture from the one of the pipes T ₁ to T ₄ through the conduit 114 or one of the equivalent conduits 124, 134 or 144 of the modules 12, 13 and 14.

The module 15 also defines a conduit 154 which opens into a channel 152 aligned with the channel 142 of the module 14 in the mounted configuration of the device. The module 15 is also equipped with a sleeve valve 156 making it possible to open or close the conduit 154.

When the valve 156 of the module 15 is open, while the valves 116, 126, 136 and 146 are closed, air flows from the source S towards the projector 1 by successively passing through the channels 152, 142 , 132, 122, 112 and the passage 162, as well as the element 16A and the pipe 6. This makes it possible to clean the device 10, the pipe 6 and the projector 1 in a particularly simple and fast manner.

The elements 11 to 16 are maintained in the form of a mechanical unit by means of two threaded rods 17 and 17 'which pass through the basic elements 111 and equivalent and the base element 151 of the module 15 as well as the head 16.

The head 16 and the module 15 are each provided with two screws 18 for mounting the element 10 on a plate not shown.

The modular nature of the device 10 makes it possible to adapt the number of modules, 11 or equivalent, to the number of coating products to be supplied to the projector 1. For example, if an additional coating is to be used in the installation of the Figures 1 to 4 it suffices to insert between the module 11 and the head 16 a module identical to the module 11 and to change the rods 17 and 17 'to use rods of suitable length. The fact that each module 11 or equivalent constitutes a part of the common collector C therefore makes it possible to permanently adapt the length of this collector to the effective number of modules used.

The arrow F _{2 represents} the flow of a mixture of entrainment gas and coating product in the conduit 114. The arrow F _{3 represents} the flow of coating product in the channel 112. The arrow F ₂ is arranged in the direction YY 'and oriented towards the channel 112 while the arrow F ₃ is arranged in the direction of the axis XX' and to the head 116. The angle α between the directions of the arrows F ₂ and F ₃ is of the order of 45 °, so that the change of direction of the flow in the zone 115 is not too abrupt, which avoids an accumulation of powder in this zone and a possible "ascent" of the mixture to the modules 12 and following.

• pour les poudres relativement faciles à transporter dans un flux d'air, plus l'angle α est faible, plus les pertes de charge au niveau de la zone 115 sont faibles. L'angle α est choisi entre 20 et 45°, la valeur de 20° étant un minimum pour une raison de conception mécanique alors que la valeur de 45° correspond à une pente maximum pour un écoulement sans heurt. Le débit de poudre utilisé peut alors être important.
• pour les poudres relativement difficiles à transporter, il convient d'éviter les aglomérats formés par fusion de la poudre dans la zone 115. Pour ce faire, on privilégie la vitesse du mélange air/poudre et les perturbations générées par un angle α marqué, par exemple compris entre 45° et 90°. Un tel angle empêche la poudre de se déposer dans la zone 115. Dans un cas défavorable où un léger dépôt viendrait à se former, il serait évacué par le mélange air/poudre arrivant ensuite. Le choix des valeurs de l'angle α est alors fait au détriment du débit maximum et peut générer des remontées de poudre vers l'amont du collecteur C.

In practice, two cases can be considered, the angle α varying from 20 ° to 90 °.

• for powders that are relatively easy to transport in an air flow, the lower the angle α, the lower the pressure drops at zone 115 are. The angle α is chosen between 20 and 45 °, the value of 20 ° being a minimum for a mechanical design reason while the value of 45 ° corresponds to a maximum slope for a smooth flow. The flow of powder used can then be important.
• for powders that are relatively difficult to transport, the agglomerates formed by melting the powder in zone 115 should be avoided. To this end, the speed of the air / powder mixture and the disturbances generated by a marked α-angle are preferred. example between 45 ° and 90 °. Such an angle prevents the powder from settling in the zone 115. In an adverse case where a slight deposit would be formed, it would be evacuated by the air / powder mixture that then arrives. The choice of the values of the angle α is then made to the detriment of the maximum flow rate and can generate upwelling upstream of the collector C.

In the second embodiment of the invention shown in figures 5 and 6 elements similar to those of the first embodiment have identical references increased by 200.

The projector 201 of this embodiment is an automatic projector supported by the arm 207 of a robot. A device 210 is provided for supplying the projector 201 from two tanks B ₁ , B ₂ each containing a coating product P ₁ , respectively P ₂ , and equipped with a Venturi drive system. V ₁ , respectively V ₂ .

The device 210 comprises a first module 211 shown with a torn half and a module 212 shown in external view, and a cleaning module 215 connected to a source S of pressurized air.

The modules 211 and 212 are respectively connected by a pipe T ₁ , T ₂ to the Venturi devices V ₁ and V ₂ , while the module 215 is connected to a source S of pressurized air by a pipe T ₅ .

The module 211 comprises a base element 2111 in which is formed a channel 2112 extending essentially in the direction of an axis X-X '. The base element 2121 of the module 212 also defines a channel 2122 which is aligned with the channel 2112 in the mounted configuration of the device. The cleaning module 2115 defines, in turn, a channel end portion 2152 in its base member 2151. A head 216 constitutes the downstream portion of the device 210 and is provided with a passage 2162 which is aligned with the channels 2112, 2122 and 2152 thus forming a manifold C for the coating product from a conduit 2114 of the module 211, bu of a conduit 2124 of the module 212.

The cleaning module 215 is also provided with a conduit 2154 for injecting cleaning air from the source S into the upstream portion 2152 of the collector C.

Each conduit 2114 or 2124 is equipped with a sleeve valve 2116 or 2126.

As before, the valve 2116 is controlled by air injection, as represented by the arrow F ₁ at the figure 5 .

In parallel to the duct 2114, a conduit 2117 extends from the entry 2113 has a connection member 2113 of the module 211 into the base member 2111. This channel comprises an upstream portion 2117A formed in the element 2113 and a downstream part 2117B formed in the element 2111, a sleeve valve 2118 being housed in this conduit, between the elements 2111 and 2113.

The downstream portion of the conduit 2117 is bent at approximately 90 °, so that it provides power to a connecting member 2111 is connected to the bin B ₁ by a pipe T _'1 of recirculation. The conduit 2117 could also be bent with an obtuse angle, the choice of the value of this angle can be made depending on the nature of the powder, as indicated above with reference to the angle α.

2113 b is the duct in which the control air is injected around the flexible portion of the sleeve valve 2116, as represented by the arrow F ₁ . 2113'b the channel, also formed in the element 2113, by which control air is injected around the sleeve valve 2118, as shown by the arrow F ' ₁ .

The operation is as follows: From a branch 2113 c between the conduits 2114 and 2117, the mixture of air and driving gas from the bin B ₁ through the pipe T ₁ is directed either towards the channel C , through the conduit 2114 and the valve 2116, either to the recirculation pipe T ' ₁ through the channel 2117, the valve 2118 and the connecting element 2111 a .

The sleeve valves 2116 and 2118 are controlled, as represented by the arrows F ₁ and F ' ₁ , to be open and closed in phase opposition, one of these valves being open when the other is closed. Coating product can flow continuously in the pipe T ₁ by being directed either to the manifold C or to the pipe T ' ₁ . Thus, when it is necessary to use a new product P ₁ or P ₂ , no transient phase of setting in motion the mixture of entrainment gas / product should be provided, the time of change of coating product between the products. P ₁ and P ₂ being very fast.

The second module 212 is made in the same way and makes it possible to recirculate the coating product P ₂ towards the tank B ₂ by means of a pipe T ' ₂ .

As previously also, the modules 211 and 212 are assembled reversibly by means of threaded rods 217 and 217 '. It is thus possible to adapt the number of modules of the device 210 to the number of coating products to be used.

The module 210 is particularly compact and, as such, it can be mounted on the arm 207 of the robot supporting the projector 201. Thus, the length of the pipe 206 connecting the device 210 to the projector 201 can be minimized, thereby minimizing also the amounts of coating material lost during a product change, these amounts corresponding approximately to the amount of coating material in the manifold C and in the conduit 206. The low volume of the pipe 206 also facilitates its rapid cleaning .

A mixed installation with one or more modules of the type of the module 11 and one or more modules of the type of the module 211 may be envisaged, as well as a combination of modules whose ducts have angles of inclination α that are different from the main direction of collector C.

Claims (8)

1. A device for supplying a powdered coating product to a sprayer in an installation spraying such a product, said supply device comprising at least two modules (11-14; 211, 212) each connected to a source (B1-B4) of coating product and each forming a part of the principal channel (112-142; 2112, 2122) of a common manifold (C) connected to said sprayer (1; 201) for circulating (F₂, F3) said product (P1-P4), characterised in that

   - the device comprises a cleaning module (15; 215) connected to a source (S) of cleaning fluid and forming an upstream part (152; 2152) of said common manifold (C),

   - said modules (11-14; 211, 212) are separable, identical and assembled in a reversible manner, their number being able to be adapted to the number of sources (B1-B4) of coating product (P1-P4) to which must be connected said sprayer (1; 201),

   - said identical modules (11-14; 211, 212), said cleaning module (15, 215) and a head (16, 216) are maintained in the form of a mechanical unit and

   - the modules (11-15, 211, 212, 215) and the head (16) are juxtaposed on an axis (X-X'), along which the parts of the main channel (112-142, 2112, 2122) are aligned.
2. The device according to claim 1, characterised in that each module (11-15; 211, 212, 215) comprises at least one valve (116, 126, 136, 146, 156; 2116, 2126, 2156) capable of placing an inlet of said module, connected to said source (B1-B4, S) of product (P1-P4) or of cleaning fluid, and said manifold (C) selectively in communication.
3. The device according to one of the preceding claims, characterised in that each module (11-15; 211, 212, 215) comprises a conduit (114, 124, 134, 144, 154; 2114, 2124, 2154) connecting an inlet of said module to the part (112, 122, 132, 142; 2112, 2122, 2152) of said manifold (C) formed by said module, said manifold formed by said modules extending in a first direction (X-X') while said conduit of each module extends in a second direction (Y-Y'), the angle
   (α) between said directions, taken in the direction of flow (F2, F3) of the product in said conduit and said manifold, being an acute angle.
4. The device according to one of the preceding claims, characterised in that each module (11-15; 211, 212, 215) comprises:

   - a base element (111, 121, 131, 141; 2111, 2121, 2151) in which is formed said part (112, 122, 132, 142, 152; 2112, 2122, 2152) of said manifold (C) and a zone of join (115) of said manifold with a conduit (114, 124, 134, 144; 2114, 2124, 2154) connected to a source (B1-B4, S) of coating product (P1-P4), or of cleaning fluid in the case of a cleaning module,

   - a connection element (113, 123, 133, 143; 2113) defining the inlet (113a, 2113a) of said conduit and

   - a valve (116, 126, 136, 146; 156; 2116, 2126, 2156) for controlling the flow of said product in said conduit, said valve being disposed between said base element and said connection element.
5. The device according to one of the preceding claims, characterised in that at least one (211, 212) of said modules forms a first conduit (2114) for supplying said manifold (C) and a second conduit (2117) for supplying a channel (T'1, T'2) for recirculation of said coating product (P1, P2) towards a source (B1, B2) of product (P1, P2), said first and second conduits extending from a common inlet (2113a) of said module.
6. The device according to claim 5, characterised in that said first and second conduits (2114, 2117) are each equipped with a controlled valve (2116, 2118) capable of allowing and/or interrupting the flow of coating product in the conduit in question.
7. The device according to one of claims 2, 4 or 5, characterised in that said valve (116, 126, 136, 146, 156; 2116, 2118, 2126, 2156) is a sleeve type valve.
8. An installation for spraying powdered coating product comprising at least one sprayer (1; 201) supplied by a device (10; 210) according to one of the preceding claims.

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