EP1309410B1 - Device for applying a coating liquid on a metal sheet - Google Patents

Abstract

The invention concerns a device for applying a coating liquid on a metal sheet comprising a lower shell (33) forming a recuperating container and an upper shell (34) mutually mobile between a closed position wherein they form a closed chamber containing feeding means, a collecting cylinder (3) and transfer means and an open position wherein they are spaced apart from each other, a container of cleaning liquid reserve (53), a container of coating liquid reserve (36), a compressed air source (47), first circulating means capable of supplying to the feeding means, in open position of the chamber, coating liquid from a coating liquid reserve container (36), second circulating means capable of supplying, in closed position of the chamber, a cleaning liquid from a cleaning liquid reserve container (53), and spraying means (39) capable of spraying cleaning liquid through at least one of the two shells to wash the elements contained in the chamber in closed position.

Description

• un cylindre d'appui rotatif autour duquel défile en continu une tôle,
• des moyens d'alimentation en liquide de revêtement,
• un cylindre collecteur de film de liquide, rotatif, alimenté par les moyens d'alimentation, et
• éventuellement des moyens de transfert du film de liquide du cylindre collecteur à la tôle défilant autour du cylindre d'appui.

The present invention relates to a coating liquid application device on a sheet, comprising

• a rotating support cylinder around which a sheet continuously travels,
• coating liquid supply means,
• a rotating liquid film collecting cylinder fed by the supply means, and
• optionally means for transferring the liquid film from the collecting cylinder to the sheet moving around the support cylinder.

We have known for a long time the coating devices of liquid paint on scrolling sheets. Commonly, we use a tray, called an inkwell, from which a rubberized cylinder takes from the paint and then transfers it to one or more successive cylinders, the last being a coating roll that applies the paint on the tape metal scrolling and resting itself on a large support cylinder (e.g., US-A-4,046,931).

Cleaning these liquid application devices from coating is needed regularly. US-A-3227078 shows a cleaning device according to the preamble of claim 1. It is very complex, asks a lot of time and the consumption of washing product is very important. Moreover, this cleaning is currently generally performed manually and has the disadvantage of being an operation risky for manpower, given the toxicity of the fumes gases and their danger of ignition.

The present invention aims to solve these problems and to develop a mechanism to overcome aforementioned drawbacks.

Advantageously, the device must be able to be cleaned of fast and efficient way.

• une coquille inférieure formant un récipient de récupération et une coquille supérieure mutuellement déplaçables entre une position fermée dans laquelle elles forment une enceinte fermée renfermant les moyens d'alimentation, le cylindre collecteur et les moyens de transfert et une position ouverte dans laquelle elles sont écartées l'une de l'autre,
• un récipient de réserve de liquide de nettoyage,
• un récipient de réserve de liquide de revêtement,
• une source d'air comprimé,
• des premiers moyens de circulation qui sont capables de fournir aux moyens d'alimentation, en position ouverte de l'enceinte, du liquide de revêtement à partir du récipient de réserve de liquide de revêtement,
• des seconds moyens de circulation qui sont capables de fournir aux moyens d'alimentation, en position fermée de l'enceinte, du liquide de nettoyage à partir du récipient de réserve de liquide de nettoyage,
• des moyens de projection qui sont capables de projeter du liquide de nettoyage à travers au moins une des deux coquilles pour laver les éléments renfermés par l'enceinte en position fermée, et
• éventuellement des moyens d'injection de gaz comprimé au travers d'au moins une des deux coquilles pour sécher les éléments renfermés par l'enceinte en position fermée.

These problems are solved by a device as described at the beginning, this device further comprising a washing apparatus comprising

• a lower shell forming a collection container and an upper shell mutually displaceable between a closed position in which they form a closed enclosure enclosing the supply means, the collecting cylinder and the transfer means and an open position in which they are spaced apart; one of the other,
• a cleaning liquid reserve container,
• a coating liquid reserve container,
• a source of compressed air,
• first circulating means which are capable of supplying the supply means, in the open position of the enclosure, with the coating liquid from the coating liquid reserve container,
• second circulation means which are capable of supplying the cleaning means, in the closed position of the enclosure, with cleaning liquid from the cleaning liquid reserve container,
• projection means which are capable of projecting cleaning liquid through at least one of the two shells to wash the elements enclosed by the enclosure in the closed position, and
• optionally means for injecting compressed gas through at least one of the two shells to dry the elements enclosed by the enclosure in the closed position.

The movement and operation of some or all these means can be done manually or automated.

This apparatus allows a reduction of the time of cleaning, a decrease in cleaning fluid consumption, which is usually a solvent for the coating liquid, and a safety and hygiene greatly improved since the vapors released by the solvent are confined in a closed chamber, starting from which they can be sucked up in a common way.

According to a particular embodiment of the invention, the washing apparatus comprises as first and second means for circulation, a circulation pump and a circuit comprising a conduit feed for introducing either coating liquid or liquid cleaning in the feeding means and an outlet duct for evacuate either coating liquid or cleaning liquid, recovery container. Advantageously, this example of a device therefore includes only one circuit at a time for the liquid supply of coating and for cleaning the feeding means.

According to an advantageous embodiment of the invention, the liquid projection means serve simultaneously to gas injection means. This device has an arrangement particularly simple and easy to handle.

Other embodiments of the following device the invention are indicated in the appended claims.

Les figures 1 et 2 représentent d'une manière schématique des variantes de réalisation de dispositifs d'application de liquide de revêtement sur une tôle.

La figure 3 représente un détail de la figure 1.

Les figures 4 à 9 représentent une forme de réalisation du dispositif suivant l'invention avec appareil de nettoyage, à différents stades successifs de son utilisation.

Other details and particularities of the invention will emerge from the description given below without limitation and with reference to the accompanying drawings.

Figures 1 and 2 show schematically alternative embodiments of coating liquid application devices on a sheet.

Figure 3 shows a detail of Figure 1.

Figures 4 to 9 show an embodiment of the device according to the invention with cleaning apparatus, at different successive stages of its use.

FIG. 1 shows a variant embodiment device according to the invention very simple, which comprises a cylinder rotary support 1 around which a sheet or band continuously moves 2. The pressed belt 2 passes into the adjustable gap, existing between the support cylinder 1 and a cylinder called manifold 3, whose peripheral surface is advantageously made of a material rubbery. The collecting cylinder 3 rotates in the opposite direction of the support cylinder 1. A feed container 4 containing liquid from coating to be applied on the strip 2 is mounted in front of the cylinder manifold 3, so as to extend along it.

This feed container 4 is represented so more detailed in Figure 3, where in the illustrated example, it is presented in the form of a feed chute of approximately prismatic. The chute 4 is open upwards and comprises a front wall 5 which is preferably parallel to the axis 6 of the cylinder manifold 3 and which extends approximately vertically. The chute further comprises a bottom wall 7 which extends obliquely towards the top, from the bottom of the front wall 5, while forming at the lower corner of the chute thus formed, an outlet opening 8 for the liquid contained in the chute 4.

A flexible squeegee 9 is, in the illustrated example, arranged adjustable way on the bottom wall 7 so as to be able to extend more or less far towards the peripheral surface of the cylinder 3. To do this, in the example illustrated, the flexible squeegee 9 is composed of several superimposed blades and each having a elongated opening which allows them to be fixed in an adjustable manner on the 7. For this purpose, bolts are provided in this example. 14, butterfly nuts 15 and pads also provided with a elongated hole. In this way it is possible to vary the distance between blades of the squeegee and the collector cylinder which will have the effect of making to flex more or less strongly these blades and thus to vary the pressure applied by the squeegee and the amount of paint that can pass on the peripheral surface of the cylinder 3.

The feed chute 4 illustrated also includes two side walls 18 and a rear wall 20.

The chute is mounted on a support bar 21, which is arranged so as to be rotatable about its axis 22, with the aid of control means not shown. We can thus adjust the opening 8 by varying the inclination of the chute by a rotation of the latter around the axis 22. This makes it possible to reduce or increase the squeegee pressure on the collector cylinder 3 depending on the flow rate request.

All these means therefore make it possible to apply the liquid of coating on the collector cylinder with a perfectly pressure determined according to need, which avoids the problem dewetting and reduce the amount of liquid needed.

In the lower side corners of chute 4 shown, two overflows can be foreseen, of which only one is represented and bears the reference 23. These overflows make it possible to evacuate flue pipes with all the liquid spilling into the overflows. These thus keep the fluid level constant inside a supply container. Deflectors 28 arranged on the bottom wall 7 uniformly distribute the coating liquid fed by a supply duct 30 in the upper part of the chute 4.

In this way, the coating liquid is always in circulation in the chute, from top to bottom, in a uniform manner, a speed precisely regulated on the quantity of liquid to pass by the flexible squeegee. This reduces by about four times the amount of fluid that is normally required when using a inkwell, while avoiding all the inconveniences associated with impurities circulating. The device is thus fed continuously with a liquid of preferably filtered and maintained at good temperature and viscosity.

As can be seen in FIG. collector cylinder transfers the coating liquid to the strip 2 by via one or more intermediate cylinders 31 and 32.

Other means of supply than those provided for in Figures 1 and 3 may also be considered by those skilled in the art. Sure the embodiment shown in Figure 2, there is shown an inkwell 27. In dashed lines, a form of realization with additional cylinder 29 resting on the cylinder manifold 3, the coating liquid being fed into the gap between these two cylinders to form a meniscus from which the liquid is driven by gravity by the collecting cylinder 3.

As is apparent from FIGS. 4 to 9, the following device the invention further comprises a washing apparatus. This one involves a recovery container 33 which, in the illustrated example, has the form of a shell. This shell 33 can for example recover any excess coating liquid projecting laterally from the collecting cylinder, of the flexible harbor, or intercalated cylinders. A conduit of discharge 34, provided with a valve 35, makes it possible to evacuate the liquid contained in the container 33 in a liquid coating tank 36, which allows the recycling thereof (see Figures 4 and 9) or in a used cleaning fluid reservoir 53 (see Figures 5 to 8).

The device illustrated in FIGS. 4 to 9 comprises a cleaning apparatus comprising in addition to the lower shell 33 described above an upper shell 37. The upper shell is preferably provided with a clearance duct 38 for the vapors and gas and spray nozzles 39 which can be connected to a flexible supply duct 40 preferably provided with a valve 41.

The shells are mutually displaceable in a manner known, not shown, and can therefore form in close position a closed enclosure as represented for example in FIG.

The supply duct 30, provided with a valve 42, is a flexible duct that is connected to the outlet of a circulation pump 43.

The output of this pump 43 is also in communicating with the flexible supply duct 40 via a pipe 44, provided at each of its two ends with a valve 45 and 46.

An air compressor 47 is also connected to the duct flexible supply 40 by a pipe 48 provided with a valve 49.

The inlet of the circulation pump 43 is connected to a flexible supply duct 50, provided with a valve 51 and a lance suction 52. This lance 52 can selectively be dipped in the coating liquid reservoir 36 (see Figure 9) or in the used cleaning fluid reservoir 53 (see Figure 5) or not immersed in any reservoir (see Figures 4 and 6 to 8).

The inlet of the circulation pump 43 is also provided with two pipes 54 and 55, each provided with a valve 56 and 57, one being immersed in the used cleaning fluid reservoir 53 and the other in a fresh cleaning liquid tank 58.

In the tank 53, an output can be provided in 59 to a reservoir of cleaning liquid to be regenerated 60.

In the illustrated example, the valves, the circulation pump and the source of compressed air can be operated according to a automated program. The opening and closing of the valves are automatically and their positions are represented on the figures and will therefore not be the subject of a more precise description.

After a coating step, it may be necessary to clean the device. After separation between the support cylinder 1 and the other cylinders in a known manner, the operator begins with purging the coating liquid supply circuit, as illustrated on the figure 4. Air is sucked into the suction lance 52, previously outlet of the tank 36. It passes through the conduit 50, the circulation pump 43 and the supply duct 30. It thus purges this supply circuit in coating liquid and the purged liquid is recovered in the shell lower 33, then recycled to the reservoir 36.

As shown in FIG. 5, the operator plunges the suction lance 52 and the discharge duct 34 in the used cleaning liquid tank 53. This is the same circuit that was used for the supply of coating liquid that serves to purge this circuit and the introduction of the cleaning liquid.

The upper shell 37 and the lower shell 33 are now in the closed position, and, for example for 10 seconds, the cleaning liquid will wash the liquid supply circuit from coating.

As illustrated in FIG. 6, the suction lance 52 is again out of the tank 53. By the pipe 55, liquid of cleaning is projected for about 2 minutes inwards from the enclosure formed by the shells, via the nozzles 39. liquid thus washes the entire device and the used cleaning fluid returns to tank 53.

During a possible subsequent sequence of example 15 seconds, illustrated in Figure 7, the valve 57 is closed and the valve 56 is opened, which makes it possible to suck cleaning liquid fresh from the tank 58 and thus rinse the installation.

In the subsequent eventual sequence represented on the figure 8 and which can last about 2 minutes, all inputs and outputs of the circulation pump 43 are closed. Compressed air is then injected by the same nozzles 39, inside the enclosure, to purge the installation and dry it. It can be provided, connected to the conduit of clearance 38 a suction system not shown.

After drying, the shells 33 and 37 are separated one on the other, as shown in FIG. 9, the suction lance 52 is again immersed in the coating liquid reservoir 36 as well that the discharge duct 34 and the supply circuit is again open. The device is then ready for a new order application.

The total time of such cleaning may be around 10 minutes and the total consumption of cleaning fluid of 20 liters, while currently we can consider a triple time and a quantity doubled of product. We must no longer consider operations manual, and often dangerous and unhealthy, cleaning by example of the sides of the cylinders.

It should be understood that the present invention is not in no way limited to the embodiments described above and that many changes can be made without departing from appended claims.

Claims (12)

1. Device for applying coating liquid to a metal sheet, 5 comprising

   a rotary support cylinder (1) around which a metal sheet (2) passes continuously,

   means of supplying coating liquid,

   a rotary cylinder (3) collecting a liquid film, supplied by the supply means, and

   means of transferring the liquid film from the collecting cylinder (3) to the metal sheet (2) passing around the support cylinder (1),

      characterised in that it also comprises a washing apparatus comprising

   a bottom shell (33) forming a recovery receptacle and a top shell (34), both mutually movable between a closed position in which they form a closed chamber enclosing the supply means, the collecting cylinder (3) and the transfer means, and an open position in which they are separated from each other.

   a receptacle (53) for a cleaning liquid reserve,

   a receptacle (36) for a coating liquid reserve,

   a compressed air source (47),

   first circulation means which are capable of supplying, to the supply means, in the open position of the chamber, coating liquid from the receptacle (36) for the coating liquid reserve,

   second circulation means which are capable of supplying, to the supply means, in the closed position of the chamber, cleaning liquid from the receptacle (53) for the cleaning liquid reserve,

   spray means (39) which are capable of spraying cleaning liquid through at least one of the two shells in order to wash the elements enclosed in the chamber in the closed position, and

   possibly means (39) of injecting compressed gas through at least one of the two shells in order to dry the elements enclosed by the chamber in the closed position.
2. Device according to Claim 1, characterised in that the washing apparatus comprises, as first and second circulation means, a circulation pump (43) and a circuit comprising a feed conduit (30) for introducing either coating liquid or cleaning liquid in the supply means (4) and a discharge conduit (34) for discharging either coating liquid or cleaning liquid, from the recovery receptacle (33).
3. Device according to one or other of Claims 1 and 2, characterised in that the liquid spraying means serve simultaneously as gas injection means.
4. Device according to Claim 3, characterised in that the spraying means serving simultaneously as injection means are connected to the aforementioned circulation pump (43) in order to make cleaning liquid circulate and to a compressed air source (47) in order to inject compressed air.
5. Device according to any one of Claims 1 to 4, characterised in that the washing apparatus also comprises purge means which are capable of making a purge gas pass through the supply means.
6. Device according to Claim 5, characterised in that the purge means supply the circulation pump and the said circuit with the said purge gas.
7. Device according to any one of Claims 1 to 6, characterised in that, in the washing apparatus, the bottom shell (33) is arranged so as to be able to be connected alternately to the receptacle (36) for the coating liquid reserve and to the receptacle (53) for the cleaning liquid reserve, so as to allow recycling of these.
8. Device according to any one of Claims 1 to 7, characterised in that the supply means comprise a supply receptacle (4) containing the said liquid and having a liquid discharge opening (8) extending along the collecting cylinder (3) in a bottom part of the said receptacle (4), and a flexible scraper (9) arranged on the supply receptacle (4) so as to limit the discharge opening (8) downwards, and to be pressed against the collecting cylinder (3) in order to apply the liquid film thereto.
9. Device according to any one of Claims 1 to 7, characterised in that the supply means comprise an ink duct in which the collecting cylinder is partially immersed.
10. Device according to any one of Claims 1 to 9, characterised in that the collecting cylinder (3) has a peripheral surface applied to the metal sheet (2) passing around the support cylinder (1).
11. Device according to any one of Claims 1 to 9, characterised in that it comprises, as transfer means, at least one rotary cylinder (31, 32) between the collecting cylinder (3) and the metal sheet (2) which passes around the support cylinder (1).
12. Device according to one of Claims 10 and 11, characterised in that the supply means comprise an additional rotary cylinder pressed against the collecting cylinder, forming between them an air gap in which the coating liquid supplied is received.

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