DE102007000722A1 - Degassing of liquid to pasty media e.g. coating paint for coating moving paper, cardboard or other fibrous web, comprises supplying the medium into container placed under vacuum, and degassing and filtering impurities in the medium - Google Patents

Abstract

The method for degassing liquid to pasty media (5) e.g. coating paint for coating of a moving paper, cardboard or other web of fibrous material, comprises supplying the medium to be degassed into a container placed under vacuum (2), degassing and filtering impurities in the medium, and then discharging the degassed medium (9) from a lower part of the container. The medium is led into a degassing area (2a) of the container by a porous filter material (11), where impurities (V) are retained for further degassing process, and removed as gas and/or air from the medium. The method for degassing liquid to pasty media (5) e.g. coating paint for coating of a moving paper, cardboard or other web of fibrous material, comprises supplying the medium to be degassed into a container placed under vacuum (2), degassing and filtering impurities in the medium, and then discharging the degassed medium (9) from a lower part of the container. The medium is led into a degassing area (2a) of the container by a porous filter material (11), where impurities (V) are retained for further degassing process, and removed as gas and/or air from the medium. The impurities and the gas and/or air are separately removed from each other. The medium passes from top to bottom of the container and is gradually degassed, where the impurities are removed towards the entry direction of the medium and the gas-rich fraction is removed from the upper end of the container. The vacuum pressure in the container is adjusted to 40-150 mbar. A fabric is used as the filter material and consists of gas-permeable, but medium and/or liquid-impermeable, ductile, tubular hollow threads, which have a mesh size of 80-120 mu m. Independent claims are included for: (1) a device for degassing liquid to pasty media e.g. coating paint for coating of a moving paper, cardboard or other web of fibrous material; and (2) a coating device for coating and/or refinement of a moving paper, cardboard or other web of fibrous material with a liquid to pasty medium.

Description

The The invention relates to a method and a device for degassing from liquid to pasty media, in particular Coating colors for coating a running paper, cardboard, or other fibrous web in a vacuum-set container, the medium to be degassed flows through it, thereby degassing and then discharged.

Media, ie liquid to pasty coating colors are usually gas or air-containing and often contain impurities. If one were to use these in coating units, the coating error on the surface of the fibrous web would cause and the order quality would be insufficient. You must therefore be previously degassed or vented and also filtered. At present, separate and sequential devices such as filters and degasifiers are used. In this context, on the WO-A1-2007 / 085688 directed. The equipment and the costs are therefore high.

In contrast, It is an object of the invention to provide a solution which does not have the disadvantages of the prior art.

The The object of the invention is achieved by a method according to Characteristics of claim 1 solved. According to the invention the degassing or venting and filtering of the relevant Medium in the same container, d. H. carried out in the same unit.

Of the technical and procedural as well as the energetic Effort is thus significantly lower than before.

It It is provided that the medium to be degassed first is introduced into a filter basket, wherein the filter basket in the Degassing tank is integrated. The medium to be degassed happens as it passes through the vacuumed container a porous filter material of the filter basket. Preferably the filter material is fine-meshed. The filter material consists of a tissue with tiny tubular hollow fibers. These hollow fibers remove the medium, or the coating color solved due to the prevailing partial pressure difference Gas or dissolved air. At the same time in the medium or in promoted the coating containing impurities upwards and against the direction of the fed to degasified medium discharged.

From The advantage is that the porous or fine mesh surface of the filter material the free surface, which for the degassing and filtering of the medium or the coating color for Available, increased, thereby their effect is increased.

Out the fine pores or narrow filter meshes with sizes between 80 and 200 microns, then passes over the medium Drainage or sliding surfaces in the degassing space of the container, where the directed from the filter basket flowing medium on is degassed. The gas bubbles, rather, the gas-containing Fraction is then removed from the container by means of a vacuum pump deducted.

The By the way, filter material itself is impermeable to water. The individual hollow preferably tubular Fabric threads of the filter material deform when inflated the medium due to the resulting overpressure, whereby the above-mentioned pore size or mesh size is reached. The impurities contained in the medium become held back and filtered the medium at the same time.

by virtue of This small mesh size can impurities or otherwise contained in the medium particles not in the rest Degassing reach, which makes the degassing process more effective.

From Another advantage is that a continuous or discontinuous and driven at a low speed of 1 to 10 rpm, rotating scraper is arranged in the interior of the filter basket. With the scraper, the inner surface (inner wall) of the filter basket, so the filter material cleaned. How nice the impurities are described in the opposite direction to the direction of the feed of the medium to be degassed transported. The impurities are then over a Deduction line pulled to the outside.

The Invention is also provided with a device according to the Characteristics of claim 8 solved. A functional description should not be done here, as these in the above explanation of the inventive method is.

advantageous Ausgestaltungsmöglichkeiten of the invention are in the subclaims to find.

The Procedures and the device work extremely well effective and cost effective. The apparatus and procedural Effort is significantly reduced compared to the prior art. In addition, there are no additional drives and also equipment for in the degassing tank arranged distribution devices, rotating plates, etc., as partially provided in the prior art, necessary.

The invention also relates to a Beschich Device for coating or finishing a running paper, cardboard or other fibrous web with a liquid to pasty application medium, in particular coating color, which is preceded by a device for degassing or venting of the application medium according to claims 8 to 19 and which a method according to Claims 1 to 7 applies.

at The coating device may be any of the known types to act by coaters. Preferably, however, is to a curtain coater (curtain coater) thought. To in this coating device create a stable curtain of coating medium and thus also achieve a very uniform order result To be able to, are particularly well-vented media he wishes.

The Invention is based on an embodiment closer be explained.

It demonstrate:

1 : A cross-section through a device according to the invention in which the method according to the invention runs

2 : a schematic view of the filter material of 1 illustrated device

3 : an enlarged view of a partial area 2

In the same reference numerals mean the same components in the figures.

In the 1 is a device 1 for degassing or venting a liquid to pasty medium, which is to be a pigment-containing coating color for coating or finishing a running paper web, shown. The device 1 consists of a cylindrical, set under vacuum degassing 2 , The degassing tank 2 indicates at its upper end 3 an inlet 4 for the medium to be degassed or coating color 5 and a vacuum generator 6 in the form of a vacuum pump. At its lower end 7 will have an outlet 8th the collecting largely degassed medium 9 dissipated.

In the container 2 is a cylindrical filter basket 10 integrated. In this concentrically arranged filter basket 10 flows at its upper end 10a the inlet 4 , The cylindrical wall of the filter basket 10 indicates on its inside 10b a porous or fine-meshed filter material 11 and on its outside 10c several lamellar superimposed drainage surfaces 12 on, for an enlargement of the surface of the medium to be degassed 5 and ensure a directed outflow. This allows gas G or air better from the medium 5 in the vacuum degassing room 2a in the lower part of the container 2 escape, where the further degassing of the medium takes place under vacuum.

In the degassing room 2a There is an absolute negative pressure of 20 to 200 mbar.

The flow path of the medium 5 Incidentally, this is indicated by arrows M. The flow is laminar and occurs without turbulent spin. The effect of the degassing is supported by a large free surface of this laminar flow. The way up the gas bubbles G is indicated by dashed lines.

Inside the filter basket 10 is a vertical, continuous or discontinuous, but at a slow speed rotating scraper 13 , the inside 10b of the filter basket 10 cleans. As a result of the rotation of the scraper 13 Impurities V and other unwanted particles are transported upwards, from where these easily via a discharge line 14 be deducted to the outside.

The filter material 11 of the filter basket 10 consists of a tissue, which in 2 can be seen more clearly. The filter material or the tissue 11 consists of gas permeable, but impermeable to liquids, deformable and juxtaposed hollow fibers 11a , The hollow fibers 11a are by means of longitudinally oriented support threads 11b connected with each other. The medium 5 For example, the fine tissue meshes, which are on the order of 80 to 200 μm, can pass, while the contaminants V, which are larger than the mesh size or pore size, can pass through 15 are, these can not happen. This will be the medium to be degassed 5 filtered at the same time. Other separate filters are saved.

3 shows an enlarged view of the filter material 11 consisting of medium-impermeable but air-permeable hollow fibers 11a and support threads 11b , The path of the gas bubbles G is also shown here with dashed lines. At the end of the hollow fibers 11a There is a vacuum atmosphere or negative pressure zone, which is the degassing of the medium 5 allows. The inflowing application medium, ie the medium to be degassed 5 forms on the upstream side of an overpressure zone, which is the hollow fibers 11a deformed, rather, presses apart and thus a mesh size 15 forms. This will be a passage of teilentgasten medium 5 and thus the said integrated filtering possible.

1

contraption

2

degassing

2a

degassing

3

upper The End

4

inlet

5

to degassing medium

6

Vacuum-generating means

7

lower The End

8th

outlet

9

degassed medium

10

filter basket

10a

upper The End

10b

inside

10c

outside

11

filter material or tissue

11a

hollow fiber

11b

support thread

12

drainage area

13

scraper

14

withdrawal line

15

mesh or pore size

G

gas bubbles

M

medium

R

Rotation direction arrow

V

pollution

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

• - WO 2007/085688 A1 [0002]

Claims (20)

Process for the degassing of liquid to pasty media, in particular coating colors for coating a running paper, board or other fibrous web in a container placed under vacuum ( 2 ), the medium to be degassed ( 5 ) flows through, thereby degassed and then discharged, characterized in that the degassing and filtering of the medium ( 5 ) in the same container ( 2 ) is carried out. Method according to claim 1, characterized in that within a degassing space ( 2a ) of the container ( 2 ) the medium to be degassed ( 5 ) through a porous filter material ( 11 ), whereby both in the medium ( 5 Contained impurities (V) from the further degassing process, as well as gas or air from the medium ( 5 ). Method according to claim 1 or 2, characterized that the impurities (V) and the gas (G) or the air separated be deducted from each other. A method according to claim 1 to 3, characterized in that the medium to be degassed ( 5 ) the container ( 2 ) flows through from top to bottom and thereby gradually degassed, whereby in the medium ( 5 ) contained impurities (V) against the entry direction of the medium to be degassed ( 5 ) and also the gas-rich fraction (G) from the upper end ( 3 ) of the container ( 2 ) and the largely degassed medium ( 9 ) from the lower end ( 7 ) of the container ( 2 ) is deducted. Method according to at least one of the preceding claims, characterized in that the vacuum pressure in the container ( 2 ) is set between 20 and 200 mbar, in particular between 40 and 150 mbar. Method according to at least one of the preceding claims, characterized in that as filter material ( 11 ) of the filter basket ( 10 ) a tissue is used, which consists of gas-permeable, but medium- or liquid-impermeable, deformable, tubular hollow fibers ( 11a ) consists. Method according to at least one of the preceding claims, characterized in that a mesh size ( 15 ) between the individual hollow fibers ( 11a ) is set between 80 and 120 μm. Contraption ( 1 ) for degassing liquid to pasty media ( 5 ), in particular coating colors for coating a running paper, cardboard or other fibrous web, comprising a container placed under vacuum ( 2 ) with a vacuum generating device ( 6 ), an inlet ( 4 ) for the medium to be degassed ( 5 ) and an outlet ( 8th ) for the degassed medium ( 9 ), characterized in that in the container ( 2 ) a filter basket ( 10 ) into which the inlet ( 4 ) for the medium to be degassed ( 5 ), wherein the filter basket ( 10 ) at least partially made of a porous filter material ( 11 ) and at least one filter material ( 11 ) clean holding scraper ( 13 ) is provided. Apparatus according to claim 8, characterized in that the container ( 2 ) as well as the filter basket ( 10 ) are rotationally symmetrical, in particular cylindrical. Apparatus according to claim 8 or 9, characterized in that the filter material ( 11 ) the inside ( 10b ) of the filter basket ( 10 ). Apparatus according to claim 8 to 10, characterized in that from the outside ( 10c ) of the filter basket ( 10 ) Drainage or sliding surfaces ( 12 ) for which the filter material ( 11 ) flowing medium ( 5 ) branch off. Device according to at least one of the preceding claims, characterized in that the drainage or sliding surfaces ( 12 ) are arranged one above the other like a lamella. Device according to at least one of the preceding claims, characterized in that the scraper ( 13 ) is formed snail-shaped. Device according to at least one of the preceding claims, characterized in that the scraper ( 13 ) is designed to rotate. Device according to at least one of the preceding claims, characterized in that the filter material ( 11 ) of the filter basket ( 10 ) is a tissue which consists of gas-permeable but medium- or liquid-impermeable hollow fibers ( 11a ), which by means of longitudinally oriented support threads ( 11b ) are interconnected. Device according to at least one of the preceding claims, characterized in that the hollow fibers ( 11a ) of the filter material ( 11 ) are deformable such that a mesh size ( 15 ) for filtering the medium ( 5 ) and the hollow fibers are furthermore suitable for removing gas (G) or air from the medium ( 5 ) and remove. Apparatus according to claim 16, characterized in that the mesh size ( 15 ) of the filter materials ( 11 ) or the hollow fibers ( 11a ) is about 80 to 200 microns. Device according to at least one of the preceding claims, characterized in that the vacuum pressure in the container ( 2 ) or in the degassing space ( 2a ) is about 20 to 200 mbar, in particular 40 to 150 mbar. Device according to at least one of the preceding claims, characterized in that the rotational speed of the scraper ( 13 ) is about 1 to 10 rpm. Coating device for coating or finishing a running paper, board or other fibrous web with a liquid to pasty application medium ( 5 ), in particular coating color, characterized in that it comprises a device ( 1 ) for degassing or venting of the application medium ( 5 ) is preceded according to claims 8 to 19, which in turn a method for degassing or venting of the application medium ( 5 ) according to claims 1 to 7 applies.