DE102008054892A1 - Curtain applicator - Google Patents

Abstract

The unit has an edge guide element (6) provided with a cover plate (7), a base plate (8) and separate chambers (9, 10) arranged on top of each other. The former chamber is located above the latter chamber. The former chamber is provided with a fluid or liquid inlet (11), and the latter chamber is provided with an outlet (12). A suction opening (17) is provided between a lower edge (16) of a wall (13) and a base plate (8). The wall has an outlet surface (19) for a fluid or liquid film (18) at a side pointed to curtain-edges. An independent claim is also included for a method for coating continuous paper and cardboard with liquid- and pasty coating medium.

Description

The The invention relates to a curtain applicator for coating a running paper, board or other fibrous web, comprising one arranged above the fibrous web and at least the Width of the fibrous web corresponding curtain application head to Delivery of at least one liquid to pasty Application medium in the form of a single or multilayer curtain, essentially following gravity on the fibrous web falls down, leading to the curtain over his fall path away, d. H. between a spoiler edge of the gun and the surface of the fibrous web at its two Edges each provided an edge guide element is, wherein the edge guide element in the width direction of Curtain is adjustable. The invention also relates to a method for curtain coating.

A generic device and a method is for example from the DE 197 35 588 known. In this document it is disclosed that for spreading the curtain at each edge a separate partial stream of coating color of the inner surface of an immediately adjacent to the outlet slit of the slot nozzle of the curtain guide element is supplied. Below the guide element, a separating element is still arranged, which separates the respective edge of the curtain and discharges to the outside.

Also an apparatus and a method are known from DE-A1 102 32 949 known. It has been proposed that, in a curtain application process, the curtain delivered by the curtain application unit is guided by edge guiding elements and corresponding emitted rays of an operating medium, as a lubricant for the curtain edges.

With the known curtain applicators several application media or multiple layers of a job medium deliverable. An embodiment of a curtain commissioned work is among others from the EP-A1-1 255 615 known and is referred to in professional circles as "Slide Die", ie Gleitschichtdüse. This so-called sliding layer nozzle contains at least two application medium chambers from which the medium in each case reaches a sliding surface of the sliding layer nozzle via a feed gap, which in turn merges in each case into a slot-shaped outlet nozzle. The application medium emerging from the discharge nozzles arranged in parallel one behind the other overlaps one another. At a trailing edge or as a detachment line to be designated edge of the nozzle, this multilayer separates and falls down as a multilayer curtain either initially on an intermediate guide plate or directly on the substrate to be coated or the surface of the moving fibrous web.

But there are also other versions of applicator heads are known in which one or more slot nozzles point down towards the underlying fibrous web. For this purpose, for example, on the DE-A1 10012344 for single-layer order and the DE-A1 10359117 directed for multi-layer order.

At the Brush - both single-layered and multi-layered Order - with the Curtain Coater (Curtain Coater) The coating width can be equal to or less than the width be the fibrous web, what as "inboard" -Fahrweise referred to as.

at so-called "overboard" driving is against it the curtain width is greater than the fibrous web width.

Especially in the inboard mode are edge guide elements, such as they are disclosed in the first two publications, necessary. These Edge guide elements guide the curtain, the approx. 200 m long, close to the fibrous web.

In The practice is currently columnar edge guide elements made of porous material. The lubricant used Fluid or water or water is still its amount undefined. The fluid or liquid used must constantly running, because otherwise danger of blockage threatens. The required amount of fluid or liquid is enormous high and is about 10 to 15 l / h.

Furthermore are the construction methods of the edge guiding elements (also the in the solutions mentioned above) complicated. They are subject to high wear and can be also still poorly clean.

It is therefore an object of the invention, an apparatus and a method in which the disadvantages of the prior art do not exist more occur.

The The object of the invention is with a curtain-commissioned work with the Characteristics of claim 1 solved.

According to the invention, the edge guide element has a cover plate and a bottom plate and consists of two superposed, separate chambers, each having a U-shaped cross section, wherein the first chamber is above the second chamber, the first chamber a fluid or Liquid inlet and the second chamber a fluid or Having liquid drain and both chambers are closed at their respective edge of the curtain facing open side of the U-section with a continuous wall so that on the one hand between the cover plate and the upper edge of the wall located in the first chamber overflow gap remains. It serves to produce a fluid or liquid film which contacts the respective curtain edge and thereby runs down a drainage surface of the wall. On the other hand, there is also between the lower edge of the outer wall and the bottom plate arranged in the lower, second chamber, central suction opening, which is in communication with the fluid or liquid drain.

The Inventive edge guide element and thus also the curtain commissioned work are characterized by a simple construction. To guide the curtain will only requires a small amount of fluid or fluid. The unwanted color beads at the edges the surface of the fibrous web are characterized by the flawless Guide the curtain and without the curtain being constricted is avoided.

The Edge guide element, in particular its the relevant Curtain edge contacting drainage surface leaves easy to clean due to its simple design.

simplified will do the cleaning work, but also the drainage behavior, if the Drainage surface made of stainless steel or aluminum. Advantageous It is when this surface is polished or a roughness value Ra from 0.8 to 1.0. The drainage surface can however also be made of plastic, especially Teflon, which shows a good flow behavior.

Regarding a variably adjusted flow amount of the leadership or better lubricity of the coating medium curtain serving fluid or liquid film, it is advantageous when the overflow gap located in the first chamber and / or the suction opening arranged in the lower, second chamber each can be adjusted in size.

Advantageous it is when the suction opening in the middle in the drain wall is arranged and parallel to the fluid or liquid withdrawal faces. The withdrawal of fluid or liquid, which with coating color particles and possibly abrasion particles Afflicted, can be done without residue.

When Fluid or fluid for the draining fluid or liquid film is preferably provided water. Alternatively, it can also be a water / coating mixture or in terms of keeping the drainage area also a Mixture containing surface-active substances, such as commercial Contains surfactants, find use.

The Suction opening for the fluid to be discharged or liquid is about 1 × 5 mm in size. This suction opening can be both vertical and horizontal be incorporated into the drain wall. Conceivable, however, would be Other opening geometries, such as circular openings. Alternately, in the bottom plate, a side slot for a Extraction or additionally incorporated a paragraph be.

Of the said overflow gap in the upper chamber is about 10 to 20 mm wide.

Advantageous it is also when the bottom plate of the edge guide element is formed obliquely, so that the slope to the course of a likewise obliquely running fibrous web is adjusted. It is conceivable that the bottom plate in adjust to a desired angle load. You have that the possibility of the edge guide, which yes very close to the underlying fibrous web should, both horizontally, as well as obliquely in upwards or downwards Use fibrous webs. Of course, it is also possible stock edgebanding elements with different formed or slanted at different angles floor panels.

The The object of the invention is also with a method according to claim 11 solved. The method is used to coat a running Paper, cardboard or other fibrous web during their Coating within a manufacturing or refining process the fibrous web with at least one liquid to pasty Application medium, which in the form of a single or multi-layered Curtain, essentially falling freely following gravity is applied to the fibrous web from above. It will the curtain over its fall path between a trailing edge and the surface of the fibrous web each at its lateral edge guided with one edge guide element. The width of the curtain can be adjusted by moving the edge guide element be set in the transverse direction.

Preferably it is envisaged that a curtain width is set, the lower than the width of the fibrous web is. This will make the curtain stroke operated in so-called "inboard driving style. this makes possible a better than previously run curtain. simultaneously This also increases the quality of the order, which the printing properties of the paper produced, for example or Cartons are rising.

According to the invention provided that for guiding the curtain, the edge guide element Fluid or a liquid is supplied. This supplied Fluid is in the first chamber of the edge guide element led upwards and through a narrow overflow gap directed. Thereafter, the fluid or the liquid flows over a run-off surface of the edge guide element after below and from there to the outside.

On the drainage surface is created by means of the narrow overflow gap a thin fluid film is formed and thus the curtain edge very well managed. The dreaded Color beads on the fibrous web and thus further contamination on track-carrying components or wet web edges do not arise.

The Efficiency of the process can be increased, if the liquid discharged via a drain or sucked the fluid or liquid film, a Traps fed and then by means of a vacuum pump in the circuit the fluid or liquid inlet of the edge guide element again is supplied.

Important is that only about 2 l / h of fluid or liquid film the run-off surface of the edge guide element flow down. These compared to the prior art very small amount is in a surprising way to impeccable leadership the curtain completely sufficient.

The Moreover, the method can be designed very effectively when the amount of the fluid film is controlled and / or regulated.

The Inventive edge guide rails can be easily retrofitted into existing ones Install curtain coating systems. The application is different Embodiments of a curtain dispensing curtain applicator head, such as B. Gleitschichtdüse or slot nozzle and possible in a single-layer or multi-layered curtain.

following The invention is based on an embodiment closer explained.

It show in a schematic representation:

1 : An inventive curtain applicator with edge guide elements in a schematic perspective view

2 : a longitudinal section through an inventive edge guide element 1 , viewed from the side,

3 : a longitudinal section through an inventive edge guide element 1 , seen from the front,

4 : a cross section through the edge guide element acc. 3 .

5 : a liquid circulation scheme for the curtain applicator acc. 1

In the 1 is a curtain commissioned work 1 for coating a running paper, cardboard or other fibrous web 2 shown with a liquid to pasty application medium. It includes, in addition to some not shown here units such as air boundary layer control devices, start-stop-Auffangeinrichtungen or pans, measuring equipment, feed lines, etc. one above the fibrous web 2 and spaced from her and only slightly hinted curtain order header 3 , This order header 3 can be designed as a so-called Gleitschichtdüse or slot and is machine width, so across the width of the fibrous web 2 reaching, executed. The order header 3 can be designed both for a multi-layer application as well as for single-layer application with a single-layer or multi-layer curtain 4 can be generated. The curtain 4 falls from the trailing edge 5 of the order header 3 from essentially the gravitational force, on the fibrous web 2 down and settles on its surface as a coating layer AS.

How out 1 can be seen, the curtain-commissioned work 1 a lateral, columnar trained edge guide element 6 in each case on leader side FS and drive side TS on. This edge guide element 6 serves the guidance and also format limitation of the approx. 200 mm long single or multilayer curtain 4 between the spoiler edge 6 and the surface of the fibrous web 2 at its lateral edges 4a and 4b ,

The edge guide element 6 is in the width direction of the curtain 4 adjustable, as the horizontal double arrows show. In the examples shown are the two edge guide elements 6 within the width of the fibrous web 2 , which is referred to as "inboard" driving.

In 2 is the edge guide element 6 out 1 , seen from the side, shown in section. It can be seen that the edge guide element 6 a cover plate 7 and a bottom plate 8th having. The edge guide element 6 consists of two separate chambers arranged one above the other 9 and 10 , where the first chamber 9 above the second chamber 10 located.

In 3 is clearer to see that the first, ie the upper chamber 9 a fluid or liquid inlet 11 and the second, so lower chamber 10 a process 12 having. Both nozzles or pipes for inlet 11 and expiration 12 point outward. Both chambers 9 and 10 also have a wall spanning both of them 13 on. This wall 13 serves the actual guidance of the curtain and therefore contacts the respective curtain edge with its side facing the curtain.

As in both 2 and 3 to recognize, is the hollow edge guide element 6 or are their chambers 9 and 10 so closed, that only between the cover plate 7 and the top edge 14 the Wall 13 one in the first chamber 9 overflow gap 15 remains. It is also located between the lower edge 16 the Wall 13 and the bottom plate 8th one in the lower, second chamber 10 arranged suction opening 17 , This suction opening is connected to the drain 12 communicates. Because of over the narrow overflow gap 15 Guided fluid results in a very thin, but uniform fluid or liquid film 18 placed on the inside of the edge guide 6 or rather on a drainage surface 19 the Wall 13 flows down and the respective curtain edge, contacted and thereby leads, whereby the curtain 4 in the 2 and 3 not shown with.

In 4 is shown that the chambers 9 and 10 each having a U-shaped cross-section. You can also see that the wall 13 with its drainage surface 18 in the curtain 4a respectively. 4b pointing open side of the U-section has been inserted.

The drainage area 19 the Wall 13 consists in the example of stainless steel with a roughness value Ra = 0.8-1.0, which is related to contamination of the drainage surface 19 and expiration behavior of the film has a very positive effect.

It should also be mentioned that the overflow gap 15 and / or the suction opening 17 are adjustable in size. The overflow gap is about 10-20 mm wide. The drainage area is just as wide 19 or the wall 13 ,

In the example, the suction opening 17 horizontally oriented and rectangular. It has a size of 1 × 5 mm. In addition, there is this opening 17 just above the bottom plate and is centered in the wall 13 parallel to the process 12 arranged.

Both chambers 9 and 10 of the edge guide element 6 are by the way by a transverse wall 20 separated from each other.

As fluid for the draining fluid or liquid film 18 , which by the way is also controllable in its quantity, preferably water is used. However, it is also a water / coating mixture or a mixture of water and surface-active substances, such as commercial surfactants used.

With the edge guide element according to the invention 6 a curtain width is set which is less than the width of the fibrous web 2 is.

In 5 a circuit diagram is shown. This clarifies that over the expiration 12 of the edge guide element 6 discharged liquid or the fluid or liquid film 18 is sucked to the outside and via a line 21 a separator 22 is supplied. The solid-particle-containing liquid is passed through a drain 23 dissipated while the "clean" liquid by means of a vacuum pump 24 from the separator 22 is sucked. This liquid is a renewed liquid feed for the edge guide element 6 to disposal. With a flow meter and control valve 25 is the desired amount of fluid or liquid via a line to the inlet 11 fed to the edge guide element.

1

Curtain applicator

2

Fibrous web

3

Curtain applicator head

4

curtain

4a, 4b

lateral curtain edge

5

tear-off edge

6

Edge guide element

7

cover plate

8th

baseplate

9

first chamber

10

second chamber

11

fluid or liquid feed

12

procedure

13

wall

14

top edge

15

Overflow gap

16

lower edge

17

suction

18

fluid or liquid film

19

drainage area

20

partition

21

management

22

separators

23

procedure

24

vacuum pump

25

control valve

L

longitudinal direction

M

application medium

FS

tender side

TS

drive side

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 19735588 [0002]
• DE 10232949 A1 [0003]
• EP 1255615 A1 [0004]
• - DE 10012344 A1 [0005]
• - DE 10359117 A1 [0005]

Claims (15)

Curtain commissioned work ( 1 ) for coating a running paper, board or other fibrous web ( 2 ), comprising one above the fibrous web ( 2 ) and at least the width of the fibrous web ( 2 ) corresponding curtain order header ( 3 ) for dispensing at least one liquid to pasty application medium (M) in the form of a monolayer or multilayer curtain ( 4 ), which essentially follows the fibrous web following gravity ( 2 ), whereby to guide the curtain ( 4 ) across its fall path, ie between a trailing edge ( 5 ) of the order header ( 3 ) and the surface of the fibrous web ( 2 ) at its two edges ( 4a . 4b ) one edge guide element each ( 6 ) is provided, wherein the edge guide element ( 6 if desired in the widthwise direction of the curtain ( 4 ) is adjustable, characterized in that the edge guide element ( 6 ) a cover plate ( 7 ) and a bottom plate ( 8th ) and of two stacked, separate chambers ( 9 . 10 ), the first chamber ( 9 ) above the second chamber ( 10 ), the first chamber ( 9 ) a fluid or liquid feed ( 11 ) and the second chamber ( 10 ) a process ( 12 ) and both chambers ( 9 . 10 ) in such a way with a wall ( 13 ) are closed, that only between cover plate ( 7 ) and top edge ( 14 ) the Wall ( 13 ) to the first chamber ( 9 ) overflow gap ( 15 ) for producing a fluid film ( 18 ) and between the lower edge ( 16 ) the Wall ( 13 ) and the bottom plate ( 8th ) one in the lower, second chamber ( 10 ) arranged suction opening ( 17 ) and the wall ( 13 ) at their respective curtain edge ( 4a . 4b ), a drainage surface ( 19 ) for the fluid or liquid film ( 18 ) having. Curtain commissioned work according to claim 1, characterized in that the first chamber ( 9 ) and the second chamber ( 10 ) each having a U-shaped cross section, wherein in the open side of the U-shaped cross section, the wall ( 13 ) is admitted. Curtain coater according to claim 1 or 2, characterized in that the first chamber ( 9 ) and the second chamber ( 10 ) through a transverse wall ( 20 ) are separated from each other. Curtain coater according to one of claims 1 or 2, characterized in that the drainage surface ( 19 ) the Wall ( 13 ) is polished and made of a material such as stainless steel or aluminum or a plastic such as Teflon. Curtain coater according to claim 4, characterized in that the drainage surface ( 19 ) has a roughness Ra of about 0.8 to 1.0. Curtain coater according to one of claims 1 to 5, characterized in that the overflow gap ( 15 ) and / or the suction opening ( 17 ) are adjustable in size. Curtain coater according to one of claims 1 to 6, characterized in that the suction opening ( 17 ) in the middle of the wall ( 13 ) and immediately above the bottom plate ( 8th ) is located. Curtain coater according to one of claims 1 to 7, characterized in that as fluid or liquid for the running fluid or liquid film ( 18 ) preferably water, but also a water / coating mixture or a mixture of water and surface-active substances, such as commercial surfactants, are usable. Curtain coater according to one of the preceding claims, characterized in that the suction opening ( 17 ) is about 1 × 5 mm in size and perpendicular or horizontal in the wall ( 13 ) is incorporated. Curtain coater according to one of the preceding claims, characterized in that the overflow gap ( 15 ) and also the drainage area ( 19 ) Are 10 to 20 mm wide. Method for coating a running paper, board or other fibrous web ( 2 ) during their coating within a manufacturing or refining process of the fibrous web ( 2 ) with at least one liquid to pasty application medium, which in the form of a single or multilayer curtain ( 4 ), which essentially follows the gravity falling freely from above onto the fibrous web ( 2 ) is applied, the curtain ( 4 ) across its fall path between a trailing edge ( 5 ) and the surface of the fibrous web ( 2 ) each at its lateral edge ( 4a . 4b ) each having a marginal guide element ( 6 ), the width of the curtain ( 4 ) by displacement of the edge guide element ( 6 ) is set in the transverse direction, characterized in that for guiding the curtain ( 4 ) the edge guide element ( 6 ) is supplied to a fluid or fluid, which is a fluid or liquid film ( 18 ) forming over a drainage surface ( 19 ) of the edge guide element ( 6 ) and then discharged. A method according to claim 11, characterized in that via a fluid or liquid flow ( 12 ) discharged fluid or liquid or the fluid or liquid film ( 18 ), a separator ( 22 ) and then by means of a vacuum pump ( 24 ) and, if desired, the fluid or liquid feed ( 11 ) of the edge guide element ( 6 ) is returned. Method according to claim 11 or 12, characterized in that the fluid or liquid film ( 18 ) the drainage surface ( 19 ) of the edge guide element ( 6 ) flows down in an amount of about 2 l / h. Method according to one of claims 11 to 13, characterized in that the amount of the fluid or liquid film ( 18 ) is controlled and / or regulated. Method according to one of claims 11 to 14, characterized in that a curtain width is set, which is less than the width of the fibrous web ( 2 ).