EP2596171B1 - Curtain applicator - Google Patents

Description

The invention relates to a curtain applicator for coating a running paper, cardboard or other fibrous web with at least one liquid to pasty application medium, comprising a above the fibrous web and spaced from her machine-wide application head with at least one application medium chamber, in each case at least one opening for the the application head emits the at least one application medium in the form of a free-falling curtain to the fibrous web and wherein the applicator head or the opening is connected to at least one application medium supply line, in the various facilities for collecting or buffering, venting, Filtering, temperature control, flow control, etc. are involved.

When painting the curtain, the dosage does not apply because there is no excess. That is, when curtain coating only the amounts are applied, which should ultimately remain on the substrate. Consequently, the quantities of application medium which have to be pumped to the curtain applicator are very small. The curtain coating also requires a venting of the coating color, because the curtain produced by the commission and is very sensitive and causes problems due to gas (air) content even before the actual coating. Moreover, in curtain coating plants, it is necessary to keep the system clean. Especially with a job media change a meticulous, time-consuming cleaning is required.

In all coating units, thus also in curtain coating, the application medium, in particular pigment-containing coating color in the feed system is finely filtered. This is important because of the generally small gap width of the dispensing nozzles, which is usually around 0.2 to 0.4 mm. A partial clogging of the nozzles (which is referred to as plugging formation) has fatal consequences, especially in curtain applicators. Namely, there is a beam splitting with contraction of the curtain edges. On the fibrous web these edges lead to a compared to the target repeatedly excessive amount of stain, which is later also rudimentary not dried. The negative sequence is that a strong color build-up occurs on subsequent rolls within a machine for the production and / or coating of the fibrous web, which is why too much cleaning effort is necessary. In addition, there is a high risk of demolition of the fibrous web and in addition the risk of damage to plastic or rubber rollers, such as in the calender. The sticking of layers of the fibrous web on the reel can also occur and lead to high rejects.

) The partial clogging can occur despite fine filtration, as valves are still arranged between the filter, for example for rinsing or for bypass, hoses and pipelines. There, particles can build up and build up everywhere in dead zones, transitions and paragraphs, etc., which then form the pluggings - ie partial blockages - during operation of the curtain application unit, especially when restarting. Curtain applicators with filter are, for example, from the EP 1533418 , of the EP 1518962 or the US 5,985030 known.

It is therefore an object of the invention to provide a curtain applicator, are avoided in the partial blockages.

The object of the invention is achieved with the features of claim 1. According to the invention, it is provided that at least one filter is provided for the respective application medium, wherein the filter is directly connected to the opening of the application medium chamber and wherein the filter has a conical filter insert with a small mesh size between 0.1 and 0.4 mm.

This is achieved in that the filter is installed immediately in front of the clip opening or integrated into the at least one opening. The filter is a so-called "police filter" which is present as the last element in front of this opening to the application medium chamber or in the opening. In contrast to the existing curtain applicators, there are no valves, branches, hoses or similar elements immediately before the opening. Partial blockages are reliably avoided.

Further advantages result in shorter cleaning times of the commissioned work, low cost, improved runnability and quality of the job. The mesh size is adjusted approximately to the width of the nozzle gap. Thus, the application medium to be used for the curtain application is filtered very fine immediately before the job and blockages are no longer to be feared.

The installation of the filter is dependent on the number and arrangement of the openings or nozzle entries. Thus, it may be appropriate in certain cases, if only one opening and thus only a single filter is present. In this embodiment, the opening and the filter can be arranged on one of the end faces of the applicator head, ie either on the drive side or on the driver's side of the machine. This version is particularly suitable for so-called slot dies (slot dies) and small machine width. The opening and thus the filter can also be arranged alternately approximately in the middle of the machine-width application head. This version is especially designed for so-called sliding layer or cascade nozzles (Slide Dies) and small machine width.

But also possible is an embodiment in which several openings per application medium chamber and thus more filters are available. In this case, the opening may be at both ends of the applicator head, i. be arranged on leader and drive side of the machine. This version will be chosen for Slot Dies (Slot Dies) with large machine width.

An alternative embodiment is also that a plurality of openings are arranged distributed over the width of the applicator head. This version is especially designed for so-called sliding layer or cascade nozzles (Slide Dies) and larger machine widths

The installation of one or as described, multiple filters can also be retrofitted into existing paint feed systems. The invention is applicable for both single-layer and multi-layer curtain applicators. In the latter case of application, a filter is thus used for one application medium or one coating color or one layer. As curtain applicator comes as already described both a slot (Slot Die) and a slide layer nozzle (Slide Die) into consideration.

It should be added that the front side of the applicator head can be connected to at least one bypass line.

In cascade or sliding nozzle (Slide Dies) you would order two pieces, so one at leader and one on the drive side of the machine, while slot nozzles (Slot Dies) requires only a bypass on the leader's side.

Depending on the mode of operation, the relatively small proportion of the application medium, which has drained off through the withdrawal line or withdrawal lines, can be returned to the media preparation. This then returns together with fresh application medium to at least one supply line.

In addition, even at the slot nozzles upwards branching vent lines are provided. Of these, there are usually several that are spread across the machine width.

Figur 1:

eine schematische Darstellung des erfindungsgemäßen Vorhangauftragswerkes in Maschinenlängsrichtung,

Figur 2:

einen Auftragskopf eines Vorhangauftragswerks in Querrichtung der Maschine gesehen mit Darstellung der Anordnung von Filtern;

Figur 3:

ein gegenüber Figur 2 veränderte Bauweise eines Auftragskopfes eines Vorhangauftragswerks Querrichtung der Maschine gesehen

Figur 4 :

eine erste Variante der Anordnung eines erfindungsgemäßen Filters;

Figur 5 :

eine zweite Variante der Anordnung eines erfindungsgemäßen Filters;

The invention will be explained in more detail with reference to an embodiment. In a schematic representation:

FIG. 1:

a schematic representation of the curtain applicator according to the invention in the machine direction,

FIG. 2:

a gun of a curtain applicator seen in the transverse direction of the machine showing the arrangement of filters;

FIG. 3:

one opposite FIG. 2 changed design of an applicator head of a curtain applicator seen transverse direction of the machine

FIG. 4:

a first variant of the arrangement of a filter according to the invention;

FIG. 5:

a second variant of the arrangement of a filter according to the invention;

Shown in the example of the FIG. 1 a curtain coater 1 as part of a fibrous web making machine or coater. The curtain coater 1 is used to coat a running paper, cardboard or other fibrous web 2 with a liquid to pasty application medium 3 for the purpose of their refinement or improvement of their printing properties.

The curtain applicator unit 1 comprises a machine-width application head 4 arranged above the fibrous web 2 and spaced therefrom, with an application medium chamber 7 extending also in the width direction from the left end side 5 to the right end side 6. An opening or nozzle inlet 8 opens into this chamber 7 for the one application medium 3. In the example, this opening 8 is arranged on the left-hand side 5 shown in the figure, which is located on the drive side TS of the machine. The application head 4 is the application medium 3 in the form of a free-falling curtain 9 to the fibrous web 2 from. The opening 8 is connected on the one hand with a coating medium supply line 10, in which various facilities for collection or buffering, venting, filtering, temperature control, flow control, etc. are included, which are designated overall for the purpose of simplifying the illustration with 11. On the other hand, the application head 4 is provided with a bypass line 12 for discharging the application medium 3.

In spite of fine filtering performed prior to curtain application, particulates accumulate and build up in the equipment indicated at 11, ie between the filter and valves, for example for flushing or by-pass, in hoses and piping in transitions, heights and dead zones, which then operate form the curtain applicator 1, especially when restarting, partial blockages. So that these are avoidable, a filter 13 is installed immediately before or in the at least one opening or nozzle inlet 8. This filter 13 serves as a so-called "police filter", which is arranged as the last element in front of the opening 8 to the application medium chamber 7 and enters into action immediately before the nozzle inlet. Im in FIG. 1 example shown is only one feed opening 8 for the an existing application medium chamber 7 and thus only a filter 13 clearly shown. Dash-dot lines indicate that, alternatively, an opening 8 'and thus a filter 13' may also be provided on the right-hand side 6 or guide side FS or alternatively approximately in the center of the machine-width application head 4 (marked 8 "and 13") or also on Leader and drive side or evenly distributed over the width of the applicator head 4 (marked with 8 '"and 13"') can be arranged.

The filter 13 or 13 ', 13 ", 13"' has a conical filter insert 14 with a mesh width Mw between 0.1 and 0.4 mm, whereby a very fine filtering is achieved.

For completeness is in FIG. 1 in addition to existing vent lines 15 which branch off to the top, including shut-off devices 16 and a drip pan 17 for outside the width B of the fibrous web 2 (overboard driving) delivered medium or curtain edge portions 18 via a discharge line 19 the color preparation process or be fed in the circuit of the medium supply 10 shown. Not shown with a star stop pan.

Shown is but another bypass line 12 on the driver's side FS, which in the example branches off at the front and also extends to the drip pan 17.

In FIG. 2 is an application head 4a of a curtain applicator 1 a in the form of a slot die (slot Die) shown in the width direction and transverse direction of the machine. The arrangement of a filter 13a, which is substantially coaxial with the application medium chamber 7a, is indicated. Also indicated is a nozzle exit slit 20 of the slit nozzle of the applicator head 4a, which has a gap width w of 0.2 to 0.4 mm and from which the curtain 9a drops onto a substrate to be coated or onto the fibrous web 2 running in the direction L and there Application layer or a so-called contour stroke 21 generated.

FIG. 3 shows one opposite FIG. 2 changed application head 4b of a curtain applicator 1 b. This application head 4b is referred to as a sliding layer or as a cascade nozzle. The applicator head 4b has in principle for each Application medium 3b to 3n on its own application chamber 7b to 7n, which merges into a respective supply gap with a corresponding outlet nozzle gap 20b to 20n. The outlet nozzle gap 20b to 20n in each case branches off from the application medium chamber 7b, 7n and ends at the surface 22 of the application head 4b designed as a sliding layer nozzle. The running single-layer or multi-layer curtain 9b then produces a single-layer or multi-layer coating medium layer corresponding to the desired number of application layers on the fibrous web not shown here.

In this embodiment, depending on the number of desired coating layers for each application medium chamber 7b to 7n, so per application medium for each application layer, depending on an opening 8a to 8n and thus a corresponding number of filters 13b to 13n present whose frontal arrangement in FIG. 3 for reasons of clarity, each indicated by a dot.

Recognizable in FIG. 3 is also how the individual application media 3b to 3n overlap on the surface 22 and these layers S fall down as a multilayer curtain 9b following substantially the force of gravity.

It should be added that the alternative arrangements of openings 8 ', 8 ", 8'" and filters 13 ', 13 "and 13"' which are also possible in FIG FIG. 1 were explained, also for the in FIGS. 2 and 3 shown embodiments apply.

In the Figur4 should be shown, the arrangement of the filter 13 immediately in front of the opening 7 of the application medium chamber 7. This figure applies analogously for openings 8 ', 8 ", 8'" and filter 13 ', 13 "and 13"'.

The FIG. 5 shows a possible arrangement of the filter 13 in the opening 8 or through the opening 8 reaching. This figure also applies analogously to openings 8 ', 8 ", 8"' and filters 13 ', 13 "and 13"'.

LIST OF REFERENCE NUMBERS

1, 1a, 1b

Curtain applicator

2

Fibrous web

3, 3a, 3b to 3n

application medium

4, 4a, 4b

gun

5

left front side

6

right front side

7, 7a, 7b to 7n

Application medium chamber

8, 8 'to 8' '', 8b to 8n

Feed gap outlet nozzle

9, 9a, 9b

curtain

10

Application medium return line

11

Facility

12

bypass line

13, 13 'to 13' ''

Application medium preparation station

14

filter cartridge

15

vent line

16

shutoff

17

drip tray

18

Curtain edge part

19

withdrawal line

20, 20a, 20b to 20n

Outlet nozzle gap

21

contour line

22

Surface of the application head

B

Width of the fibrous web

FS

tender side

L

direction

S

layer

TS

drive side

mw

mesh

w

gap width

Claims (6)

1. Curtain applicator (1, 1a, 1b) for coating a running paper, cardboard or other fibrous web (2) with at least one liquid to pasty application medium (3, 3a, 3b to 3n), comprising a machine-width wide application head (4, 4a, 4b) which is arranged above and spaced apart from the fibrous web (2) with at least one application medium chamber (7, 7a, 7b), into which in each case at least one opening (8, 8' to 8"', 8b to 8n) for the relevant application medium (3, 3a, 3b to 3n) which is fed in opens, the application head (4, 4a, 4b) discharging the at least one application medium (3, 3a, 3b to 3n) in the form of a free-falling curtain (9, 9a, 9b) onto the fibrous web (2), and the application head (4, 4a, 4b) or the opening (8, 8' to 8"', 8b to 8n) being connected to at least one application medium feed line (10), into which various devices (11) for collecting or buffering, ventilating, filtering, temperature control, quantity control, etc. are incorporated, at least one filter (13, 13', 13", 13"') for the application medium (3, 3a, 3b to 3n) being provided, which filter (13, 13', 13", 13"') is connected directly to the opening (8, 8', 8", 8"', 8b to 8n), characterized in that the filter (13, 13', 13", 13"') has a conical filter insert (14) with a mesh size (Mw) of between 0.1 and 0.4 mm.
2. Curtain applicator (1) according to Claim 1, characterized in that the filter (13, 13', 13", 13"') is installed directly in front of the opening (8, 8', 8", 8"', 8b to 8n) or is integrated into the at least one opening (8, 8', 8", 8"', 8b to 8n).
3. Curtain applicator (1) according to Claim 1 or 2, characterized in that the opening (8, 8') is arranged on one of the end sides (5 or 6) of the application head (4) or the at least one application medium chamber (7).
4. Curtain applicator (1) according to Claim 1 or 2, characterized in that the opening (8") is arranged approximately in the centre of the machine-width wide application head (4) or of the at least one application medium chamber (7).
5. Curtain applicator (1) according to Claim 1 or 2, characterized in that the opening (8, 8') is arranged in each case on both end sides (5, 6) of the application head (4) or of the at least one application medium chamber (7).
6. Curtain applicator (1) according to Claim 1 or 2, characterized in that a plurality of openings (8"') are arranged distributed over the width of the application head (4) or of the at least one application medium chamber (7).

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