EP1502661A2 - Apparatus for applying a coating to plate-like workpieces - Google Patents

Abstract

The paint applicator for flat workpieces (1) has an application roller (3) and a spaced metering feed for paint onto the roller. The metering feed has a metering roller (4) and a reservoir (5) between the application roller and metering feed. The reservoir has a paint level control fed (6) to the reservoir. The reservoir has a paint homogenizing mixer parallel to the gap between the roller and paint feed.

Description

The invention relates to a device for applying a liquid application medium, in particular paint, on flat workpieces by means of a the application roller rolling off the workpiece and one for forming a gap on the lateral surface of the applicator roll engageable metering device, in particular in the form of a rolling on the applicator roll metering roller, in such, that above the gap between the applicator roll and metering device Reservoir for the application medium is created, its refilling through a supply line above the level of the application medium in the reservoir, the refilling in particular by discontinuous pumps such as Diaphragm pumps take place.

Such rolling machines are in many embodiments and for application different order media known. Their main area of application is the application of paint on plate-shaped workpieces, see EP 427 045. The metering device usually consists of an engageable with the applicator roll metering; instead, it can also consist of a doctor blade, cf. For example, DE 100 30 310. In both cases arises above the Spaltes an approximately V-shaped reservoir in which the application medium with a certain minimum level. The frontal conclusion of this Reservoirs are usually made by so-called finishing jaws, which are on the front sides the applicator roll are arranged.

The filling of the reservoir via a supply line with free outlet above the level of the application medium, usually in the middle of the machine. The delivery rate is adjusted so that a slightly larger Amount is funded as it meets the current need. The excess Amount of application medium runs over the top edge of the side End jaws in return lines to the pump tank in the Back cycle of the order medium.

Investigations by the applicant have now shown that at high requirements to the surface quality, especially when applying paints with Solid content, sometimes optical irregularities in the surface texture and that these job errors may be with discontinuous ones Pumps occurring refill impact related.

Attempts of the applicant to the inflow of the application medium in the reservoir uniform, in particular by Verteilrinnen with over the roll width distributed drainage holes, although some improvement. simultaneously but caused spatial problems, because of the dosing and application rollers attack usually swivel mounted doctor blade, which then with the distribution channel can collide. It also makes the cleaning of the machine very much difficult.

On this basis, the present invention is based on the object, a Roller application device of the type described above in terms of Improve coating quality, especially in such applications, where the supply of the application medium in the reservoir through discontinuous pumping takes place, as in highly abrasive and aggressive Paints are necessary.

This object is achieved in that in the reservoir arranged in the application medium immersing homogenizer, which runs in the longitudinal direction approximately parallel to the gap and in the transverse direction so is arranged, that its upper side predominantly from that from the feed line outflowing application medium is applied.

By this measure, the surge-like supply from the supply line no longer - at least not in full - on the free liquid surface of the reservoir, but this refill impulse is quite or partially absorbed by the Homogenisierkörper and thus in his Dynamics weakened considerably. The previously occurring disorder in the paint flow of the reservoir is thus drastically reduced and the so-called Glossy stripes on the product surface are reliably removed. Furthermore omitted the mentioned distribution channels and their complex cleaning.

So that the application medium regardless of its viscosity and its conveying speed on the homogenizer, it is recommended that the Supply line at least one directed to the homogenizer spout, but preferably a plurality in the cleavage direction successive, such having aligned outlet openings. These openings can almost be extend over the entire length of the reservoir.

With regard to the Homogenisierkörpers it is also recommended that he himself extends over almost the entire length of the reservoir, for reasons the easier cleaning preferably with a continuous body instead worked several single body. The shape of the homogenizer is suitably circular cylindrical. He can rotate in the reservoir - be it solely because of the developing stream, be it due to temporary Attachment to the applicator roller or metering roller. Instead, the Homogenizer but also be arranged non-rotatably in the reservoir, about as a wedge-shaped strip.

So that the Homogenisierkörper its damping properties on the inflow of the order medium can optimally meet, it is recommended that he at least in the vertical direction, preferably stored floating freely in the reservoir is, so he always with his top off regardless of filling level appears in the application medium. Thus this positioning for order media with very different specific gravity can be maintained It is within the scope of the invention, either different mass homogenizer to use or the Homogenisierkörper is in a level control stored; which always keeps him in a partially submerged position, regardless of how high the reservoir is filled and what specific weight the order medium has.

A particularly advantageous embodiment of the homogenizer in that it is designed as a hollow body and its interior with different Is to fill weights. As a result, its weight can be optimally adapted to the specific weight of the order medium to be adjusted, such that its ideal immersion position is ensured. The weights can be around Cylindrical inserts made of different material that are easy to handle in the likewise cylindrical homogenizing body are inserted axially, so that they frictionally and / or positively in the interior of Homogenisierkörpers being held. Instead, the weights may also be around loose fillers act like granules.

Thus, the floating in the application medium Homogenisierkörper not on the rotating applicator roll, in particular not between two rollers jammed, it may be appropriate to the maximum Absinkbewegung the Limit homogenizer by stops. These attacks can be placed in the reservoir and either with the outer circumference of the homogenizer correspond or arranged with the front side centrally Cones or the like.

Appropriately, the homogenizer is vertically displaceable at its outer ends stored on the frontal end jaws of the reservoir. however For this other storage options come into consideration; in principle the homogenizer can even float freely in the reservoir be inserted.

Further investigations of the applicant have shown that a considerable Improvement of the surface quality of the applied medium also by it can be achieved that the feed of the application medium in the gusset room between doctor blade and applicator roll is laid, in which case the homogenizer can be dispensed with. The doctor blade will then expediently arranged slightly deeper on the circumference of the applicator roll, namely on the level of the reservoir resulting from the previously described design, so that a sufficiently steep alignment of the gusset space between doctor blade and applicator roll achieved.

Fig. 1

einen Ausschnitt aus einer Lackwalzmaschine im Querschnitt gemäß einer ersten Alternative;

Fig. 2

den gleichen Ausschnitt gemäß einer zweiten Alternative;

Fig. 3

eine Ansicht von oben;

Fig. 4

eine Stirnansicht mit dem Lagerschild für den Homogenisierkörper und

Fig. 5

einen Ausschnitt entsprechend Fig. 1 bei einer dritten Alternative.

Additional features of the invention will become apparent from the following description of an embodiment with reference to the drawings and the drawing itself; shows

Fig. 1

a section of a paint rolling machine in cross section according to a first alternative;

Fig. 2

the same section according to a second alternative;

Fig. 3

a view from above;

Fig. 4

an end view with the bearing plate for the Homogenisierkörper and

Fig. 5

a section corresponding to FIG. 1 in a third alternative.

In Figures 1 and 2 can be seen a plate-shaped workpiece 1, on the Top side a solid-based paint with a small layer thickness, in the embodiment from about 5 μ to about 20 μ should be applied. The applicator initially has the usual structure, namely a lower transport roller 2 and an overlying applicator roll 3, between which the Product is transported horizontally. The application roller 3 works with a slightly smaller metering roller 4 together, such that between the two rollers a minimal gap arises, above which a paint reservoir 5 is located. The paint reservoir 5 is alongside by the two against each other Peripheral surfaces of the applicator roller 3 and the metering roller 4 is formed so that it receives an approximately V-shaped cross section, whereas it is not at the front by here Pictured, known per se end jaws is limited.

By far above the reservoir you can see a supply line 6. It is to a discontinuous pump used in coatings with solids connected and pours the paint from above through a terminal opening 6a into the reservoir 5. As Figure 3 shows, the supply line 6 extends in the longitudinal direction of the reservoir, and only about 1/3 of the reservoir length. These Position of the drain opening 6a results in connection with the delivery pulse a relatively homogeneous mixing of the subsequent quantity of paint with the already in the reservoir located paint. Of course, the drain opening but also protrude further into the middle region of the reservoir length.

Finally, two doctor blades 7 and 8 can be seen in FIGS. 1 and 2, in a conventional manner with their associated metering roller 4 and Application roller 3 interact.

In so far, the rolling machine described has the known structure.

It is essential that in the reservoir 5, approximately below the supply line 6 a Homogenisierkörper 9 floats, with a certain distance is arranged between two rollers and partially in the reservoir immersed standing paint, but protrudes from the top of the paint. In Figure 1 detects one that the paint coming from the supply line 6 for the most part Part does not fall directly into the reservoir 5, but on the Homogenisierkörper 9 hits. As a result, the Homogenisierkörper takes the from the jerky Delivery characteristic of the pump resulting pulses and prevented their transfer to the Abströmspalt between applicator roll 3 and metering 4 and thus on the surface of the paint film on the workpiece.

In the alternative shown in FIG. 1, the homogenizing body is made an approximately wedge-shaped bar that tapers down and this orientation also retains, whereas they preferably floating in the vertical direction is stored.

In the alternative shown in FIG. 2, the homogenizing body takes place of which a round rod 19, which floats freely rotatable in the reservoir. This results in the following effect: As a result of the rotation of dosing and application roller - regardless of whether the rollers rotate the same or in opposite directions - arises usually also a circulation of the paint liquid to one to the roll axes parallel axis. This circulation of the paint liquid produces a same direction rotation of the rod-shaped homogenizer 19 - optionally even more intensified by its tangential contact with one of the two Rolls 3 or 4. Thus, the top of the Homogenisierkörpers jerky falling paint stream in a considerably uniform form the reservoir 5 supplied.

FIG. 4 shows an end view of the paint rolling machine. One recognizes there in particular a bearing plate for the frontal storage of Homogenisierkörpers 9 or 19. It consists of a bearing plate 10, which at the same time also the frontal End jaw for the rollers 3 and 4 forms. For this she has an approximately vertical, upwardly open slot 11, in which the axially projecting Ends of Homogenisierkörpers 9 or 19 are stored, in the case of Homogenisierkörpers 9 non-rotatable, in the case of the homogenizer 19 rotatable. In In both cases, the Homogenisierkörper without additional tools after are removed from the top plate 10 so that its cleaning easily possible.

Fig. 5 shows an alternative design, dispensed with the Homogenisierkörper becomes. Instead, this is cooperating with the applicator roll 3 Abstreifrakel 8 laid down further down and made steeper and the supply line 6 is no longer between the two squeegee blades, but between the doctor blade 8 and the applicator roll 3, so that in the formed there gusset space the paint reservoir 15 forms.

It is of course within the scope of the invention, the homogenizer also to use in the alternative shown in Fig. 5.

In summary, the invention offers the advantage that by interposition a Homogenisierkörpers in the form of a float or by the lateral displacement of the feed line between applicator roll and associated Abstreifrakel a direct impact of the effluent from the supply line Application medium in the reservoir and the resulting disturbances of the Inlet conditions are largely avoided in the dosing. The previously occurring defects in the surface texture of the painted product are thereby reliably eliminated.

Claims (11)

Apparatus for applying a liquid application medium, in particular lacquer, to flat workpieces (1) by means of an applicator roll (3) rolling on the workpiece (1) and a metering device which can be set to form a gap on the lateral surface of the applicator roll (3), in particular in the form of a on the applicator roller (3) rolling metering roller (4), such that above the gap between applicator roll (3) and metering a reservoir (5) for the application medium is formed, the filling of which by a supply line (6) above the level of the application medium in the reservoir (5), wherein the filling is carried out in particular by discontinuous pumps such as diaphragm pumps,
characterized in that in the reservoir (5) at least one immersing body (9, 19) immersed in the application medium is arranged, which extends in the longitudinal direction approximately parallel to said gap and which is arranged in the transverse direction so that its upper side at least partially from the from the supply line (6) effluent application medium is applied. Device according to claim 1,
characterized in that the feed line (6) has at least one outlet (6a) directed onto the homogenizing body (9, 19). Device according to claim 1,
characterized in that the application medium coming from the feed line (6) impinges on the homogenizing body (9, 19) distributed over a certain longitudinal section. Device according to claim 1,
characterized in that the homogenizing body (9, 19) is rod-shaped. Device according to claim 1,
characterized in that the homogenizing body (19) is freely rotatably mounted. Device according to claim 1,
characterized in that the homogenizing body (9, 19) is freely floating at least in the vertical direction. Device according to claim 1,
characterized in that it comprises stops which limit the lowering of the homogenizing body. Device according to claim 1,
characterized in that the homogenizing body is designed as a hollow body which is to be filled with weights. Device according to claim 1,
characterized in that the homogenizing body (9, 19) is mounted at its ends on end-side end jaws (10) of the reservoir (5). Device according to claim 1,
characterized in that the homogenizing body (9, 19) is mounted freely removable upwards. Device according to claim 1, wherein a doctor blade (8) is arranged on the applicator roll (3).
characterized in that - optionally waiving the Homogenisierkörper - the inlet (6) of the application medium in the gusset space between doctor blade (8) and application roller (3) is laid.

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