DE102006026413A1 - Degassing liquid or pasty coating medium for coating on paper or cardboard web using an application tool, comprises isolating the gas contained in the coating medium over a membrane in existence of a partial pressure difference - Google Patents

Abstract

The degassing of a liquid or pasty coating medium (2) for coating paper or cardboard web in an application tool, comprises isolating the gas (10) contained in the coating medium over a membrane (7) in existence of a partial pressure difference. The coating medium is supplied to an inflow side (11) of the membrane. The partial pressure difference is produced over the membrane through the concentration difference of the gas to be isolated at the inflow side of the membrane and the discharge side of the membrane as permeate side (12). The degassing of a liquid or pasty coating medium (2) for coating paper or cardboard web in an application tool, comprises isolating the gas (10) contained in the coating medium over a membrane (7) in existence of a partial pressure difference. The coating medium is supplied to an inflow side (11) of the membrane. The partial pressure difference is produced over the membrane through the concentration difference of the gas to be isolated at the inflow side of the membrane and the discharge side of the membrane as permeate side (12). The permeate is supplied to the coating medium in cross reverse flow principle along the medium. The concentration of the gases at the inflow side is higher than the permeate side at which a vacuum is created. A gaseous medium is applied or supplied on the permeate side as carrier medium for isolating the gas in the coating medium. A fluid medium, which is free of gas or which has slight gas concentration, is applied or supplied on the permeate side. The permeate is sucked off by vacuum after discharging of the membrane from the permeate side. The dissolved- and/or the free gas are isolated over the membrane. The portion of the dissolved gas in the coating medium is controlled in the contact area of the membrane. The free gas is transformed in the medium through pressure and/or temperature change in the dissolved gas. The membrane is made of hydrophobic material. The separation degree of the permeate is influenced through type of the membrane material, thickness and size of the coating area, contact time of the coating medium with the membrane, and partial pressure difference over the membrane. The membrane is used in the form of hollow fiber or capillaries. The membranes associated to a membrane module separate a material flow from the coating medium and are led over contacting modules arranged parallel to each other. Independent claims are included for: (1) device for degassing liquid or pasty coating medium; and (2) a color provision system.

Description

The The invention relates to a method for degassing a liquid or pasty Coating medium, in particular coating color for application to a fibrous web in a commissioned work, in particular coating color deaeration process, in detail with the features of the preamble of claim 1; Furthermore, an apparatus for degassing a liquid or pasty coating medium and a color delivery system for a commissioned work.

at Refining processes of material webs, in particular fibrous webs in the form of paper or board webs by the application of a coating, especially coating on the moving web, comes the Quality, especially the homogeneity of the medium to be applied is of great importance. To get a uniform coating to ensure the fibrous web the order layer may not show any defects. The Coating color is during and after mixing in a paint delivery system upstream of the commission stored and guided. To the during the processes in the paint delivery system, especially after mixing and successful leadership in appropriate storage containers or intermediate tanks and not escaped from the coating color Gas bubbles, in particular in the form of air bubbles and dissolved gas, To eliminate, a degassing of the coating medium before the order made on the fibrous web. Only after this is the coating medium with coating units adapted to the fibrous web width applied at high speeds. For degassing, for example Turntable vacuum degasser used. The otherwise usual Hydrocyclones with separation limits of about 200 microns bubble size are not sufficient for this method.

The currently for degassing of liquid until pasty Coating medium, in particular coating color, devices used, such as gravity vent or vacuum vent often only partially successful. In particular, these are only for the treatment of volume flows small size suitable, so as to provide either a plurality of such devices are or the individual device sized accordingly must become. This means besides an enormous amount of equipment, also a correspondingly high cleaning and maintenance costs. The Operating principle of vacuum ventilation systems is based on the creation of new surfaces under a vacuum of 1 to 100 mbar (absolute pressure). Although the efficiency of this type of deaerators already between 95 and 99%, the degree of separation of gas is often not sufficient to a defect-free To produce coating on a fibrous web. Especially very small gas bubbles, for example in the order of ≤ 200 microns, and in particular in The coating gas present in the coating color is only in the vacuum fan difficult to remove and visible in the coating as imperfections.

The problem of degassing is already known from the prior art from a variety of areas. The degassing is carried out by mechanical, chemical or other means. Out US 5,123,937 In general, a method of degasification is previously known in which a liquid containing gas and gas bubbles is passed in an air separation system for the removal of bubbles and further supplied to a venting module comprising a gas-permeable membrane.

Another venting device according to the membrane process is in the document US 5,269,836 described. This discloses a passive membrane vent in which solid components of a photographic material are introduced and pumped against a hydrophobic membrane element. Air between the individual elements is conveyed through the membrane by the pressure and a vacuum applied to the opposite side of the membrane. These solid components of a photographic material are liquefied and the resulting medium is deaerated by means of ultrasound. Another possibility for removing gases, in particular carbon dioxide via a membrane, can be found in WO 2006/004400.

Of the Invention is therefore the object of a method and a Device for degassing a liquid or pasty coating medium, in particular coating color for to refine the finishing of a fibrous web such that the mentioned disadvantages are avoided and the coating color in one quality can be provided at a curtain applicator, the defects in the subsequent order almost avoids. In detail is to further reduce the gas content in the coating color, so that it no longer visible to disturbances by blowing and contained in the coating color, in particular dissolved gas the fibrous web comes. The spread medium present after degassing intended to meet the requirements for a coating medium of a curtain applicator plant correspond. Furthermore, the solution according to the invention by a smaller constructive Effort and required energy input against the already known from the prior art designs and the vent make it more efficient overall, so that either smaller or but a smaller number of vacuum venting systems are used have to.

The inventive solution by the features of the claims 1, 16 and 29 characterized. Advantageous embodiments are in the subclaims described.

According to the invention is for Degassing a liquid or pasty Spreading medium for application to a dye web a membrane method used. This is understood to mean a separation process on a membrane, wherein at least one component of the mixture to be separated, here in the Gas contained in the coating medium passes through the membrane, while the other components are more or less withheld. It will in the gas to be degassed gas contained via at least one membrane deposited in the presence of a partial pressure difference across the membrane penetrates as Permeate the membrane and occurs on the opposite side of the membrane out. The stripping medium to be degassed is permeated around the membrane Gas depleted. This is depleted of the gas stream referred to as retentate, i. it results after the contact of the degassing coating medium with the membrane two streams, once for the the membrane penetrating permeate and that on the contact side flowing, coating medium depleted of the permeate in the form of the retentate. Driving force for it is the difference in activities on both sides of the membrane. in particular the partial pressure difference due to concentration differences.

The Gas contained in the coating medium can be used both as free gas as well as in dissolved Form present. about the membrane is dissolved Gas deposited by permeation and free gas by diffusion.

With the solution according to the invention a separation of in to be degassed coating medium, in particular Coating color of existing gas in a simple way and without significant energy input already possible through the corresponding flow control. Especially low levels of gas either no longer with other methods or at least very uneconomically separable, can be efficient be deposited.

Under the coating medium to be degassed are coating color and glue, especially pigmented glue and starch understood. In the painting medium For example, gases can be components of Air and carbon dioxide act.

• a) Anlegen eines Vakuums an der Permeatseite
• b) Anlegen oder Führung eines gasförmiges Mediums mit einer geringeren Gaskonzentration als im zu entgasenden Streichmedium
• c) Vorsehen oder Führung einer gasarmen oder gasfreien Flüssigkeit

The stripping medium to be degassed is guided on one side of the membrane to this inflow. The partial pressure difference across the membrane is generated by concentration differences between the gas to be separated from the membrane sides facing away from one another, from the side to be degassed coating medium or side and the outlet side for the separated gas. In this case, it is decisive for the deposition process that the concentration of the gas to be separated in the coating medium to be degassed must be greater than the concentration in the coating medium on the opposite membrane side, in particular the outlet side for the permeate, referred to as the permeate side. This can be realized by the following measures:

• a) applying a vacuum on the permeate side
• b) creating or guiding a gaseous medium with a lower gas concentration than in the stripping medium to be degassed
• c) Provision or management of a gas-poor or gas-free liquid

In order to avoid an increase in the concentration of separated gas on the permeate side, which leads to a reduction in the partial pressure difference, the permeate is aspirated after leaving the membrane and / or removed with the liquid or gas flow of the adjacent to the permeate side and along this medium or washed away. These processes are preferably carried out continuously. If gaseous medium is conducted as the carrier gas for the permeate on the permeate side, it is preferable to choose a gas of a foreign nature to contain the gas to be degassed in the stripping medium. It is conceivable, for example helium or the desired CO ₂ separation, the use of air, in particular ambient air.

• a) Gleichstromprinzip oder
• b) Gegenstromprinzip oder
• c) gemäß einer besonderen vorteilhaften Ausführung zur Erhöhung der Wirkungsweise nach dem Kreuzgegenstromprinzip geführt werden.

The permeate, the medium provided on the outlet side of the membrane and the coating medium to be degassed can be applied to the membrane in the

• a) DC principle or
• b) counterflow principle or
• c) are performed according to a particular advantageous embodiment to increase the mode of action according to the cross countercurrent principle.

Preferably Membranes are used, which prevent the passage of gases in Spreadable media may be included especially favor the constituents of air.

The Effect of the degassing process is due to the structural design, in particular the dimensioning and properties of the membrane can be influenced. This includes among other things the material, the surface condition, the thickness the membrane as well as the size of the effective Membrane area.

• – Kontaktzeit für das zu entgasende Streichmedium mit der Membran bzw. Verweildauer
• – Durchsatz des zu entgasenden Streichmediums
• – Größe der Konzentrationsunterschiede für das Gas über die Membran betrachtet

The degassing can also be actively influenced during the degassing process by changing the process parameters, in particular controlled become. These include:

• - Contact time for the to be degassed coating medium with the membrane or residence time
• - Throughput of the to be degassed coating medium
• - Size of the concentration differences for the gas across the membrane considered

The Contact time itself results as a function of the effective Membrane surface and / or the throughput of degassed media.

The Device for degassing of coating color is inventively as Membranentgasungsvorrichtung executed. This comprises at least one membrane, which at least a partial surface of a Boundary wall or guide wall for coating color in the paint delivery system. A plurality of individual membranes or a single membrane form a module which is flowed through by the stripping medium to be degassed and in a leadership system for the to be degassed coating medium, in particular coating color integrable is.

According to one particularly advantageous embodiment become an increase the throughput and adaptation to different required throughputs degassing provided with a plurality of modules, which are connected in parallel. To increase the rate of deposition can also Series circuits are provided, in particular when the order to Gas-depleted coating medium after passing through a separation stage still has too high a gas content.

• – Polysiloxane und deren Derivate
• – Polytetrafluorethylen und Derivate
• – Polyolefine und deren Derivate, insbesondere Polyethylen und Polypropylen

With regard to the embodiments of the membranes used a variety of ways are conceivable. With regard to the materials, these may be made of hydrophobic materials, porous or nonporous. The structure of the membranes used is either symmetric or asymmetric. The single membrane can be constructed on the basis of one of the following materials:

• - Polysiloxanes and their derivatives
• - polytetrafluoroethylene and derivatives
• - Polyolefins and their derivatives, in particular polyethylene and polypropylene

According to one particularly advantageous embodiment the membrane module is designed as a hollow fiber module comprising a plurality of axially parallel to each other arranged hollow fibers, preferably can be flowed around by the coating medium to be degassed, wherein the hollow fibers with a drain for that guided in these discharged from the gas to be degassed coating medium over the membrane separated gas are connected. The module also has at least an exit for the retentate. It is also conceivable, the coating medium in the hollow fibers respectively. The permeate is then outside the hollow fibers out. The advantage of such a module is especially in the provision of very greater effective membrane surfaces in the smallest space.

The inventive solution especially for the degassing of coating color in one, a commissioned work in the form of a curtain applicator upstream color supply system suitable. The membrane degassing device can there at any Place between color supply system and commissioned work provided become. For versions with a vacuum fan the arrangement is preferably in this and is used to discharge the Used residual gas content or but can also be used as sole or additional measure be used to other degassing.

The solution according to the invention explained below with reference to figures. This is in detail the following is shown:

1 illustrates in schematic simplified representation of the basic principle of a method according to the invention.

2a - 2d illustrate various embodiments of an inventively designed device for venting;

3 illustrates in a schematic simplified representation of a particularly advantageous embodiment of a provided for the venting of coating color membrane module;

4 illustrates an advantageous arrangement possibility of operating according to the membrane method apparatus for venting coating color in a paint supply system;

5 exemplifies the structure of a possible embodiment of a membrane system.

The 1 illustrates in simplified schematic representation a first embodiment of a device according to the invention 1 for degassing a liquid or pasty coating medium 2 , which is in the form of a coating color 3 is present. The device is therefore also known as a paint degassing device 4 designated. This is arranged within a paint delivery system, wherein the paint delivery system is arranged upstream of a commissioned work order to a fibrous web for the purpose of finishing. According to the invention, in the guide system for the coating medium to be degassed 2 , in particular the coating color 3 at least one subarea 5 a wall 6 from a membrane 7 formed, at which the gas to be degassed coating medium 2 while contacting the membrane 7 flows along or flows to them at an angle. The streamed or to be degassed coating medium 2 touched membrane side is called inflow side 11 designated. The device 1 is therefore also used as a membrane degassing device 8th denotes and comprises at least one membrane module 9 for the separation of gas 10 , in particular of dissolved gas from the coating medium 2 , The membrane module 9 includes for this purpose at least one single membrane 7 or a plurality of these, through which in the to be degassed coating medium 2 contained gases by permeation or diffusion from the coating medium 2 be encouraged. The membrane 7 is preferably made of hydrophobic material. The the upstream side 11 opposite membrane side, on which the separated gas exits as permeate P, is called permeate side 12 designated. The degassing is based on the partial pressure difference between the stripping medium to be degassed 2 in the area of the inflow side 11 and the permeate side 12 , ie of the medium present there 16 , The membrane module 9 has at least one inlet 13 for the coating medium to be degassed 2 and a process 14 for the degassed coating medium depleted of permeate P, which is also referred to as retentate R, on. Will the to be degassed coating medium 2 now along the membrane 7 , especially the surface 15 guided, takes place due to the interaction with the on the upstream side 11 opposite membrane side, the permeate side 12 attached medium 16 a separation of the gas 10 from the coating color 3 through passage through the membrane 7 , This results in two streams in the module, the permeate flow through the membrane 7 and the Renetatstrom R from the module 9 out. In the latter, the particles are included, which do not penetrate the membrane and are retained at this, ie the coating color 3 ,

The generation of the required for the permeation and diffusion partial pressure differences on the opposite sides of the membrane 7 is thereby by concentration differences of the gas to be separated 10 in both sides of the membrane 11 . 12 created adjacent media and / or the application of pressures. This is the medium with the higher concentration of gas to be deposited 10 the stripping medium to be degassed 2 , in particular the coating color 3 , As a medium on the permeate side 12 becomes medium 16 with a lower concentration of a gas corresponding to the gas or gases to be deposited. Preferably, vacuum, an inert gas or a gas-free liquid medium is applied. As a liquid medium, the use of water is conceivable, which has previously been largely freed of gas by vacuum and heating, especially cooking.

To maintain the concentration differences, the separated gas 10 on the permeate side 12 discharged, preferably directly via a Permeatabfuhr 17 or when using a gaseous or liquid medium 16 as a carrier or transport medium via the leadership of the medium of an inlet 21 to a process 22 over this with discharged.

The Terms inlet and outlet include inlet and outlet and can tubular, tubular or channel-shaped accomplished be. The terms are to be understood as functional, i. One- or discharge, no matter in what way.

The 2 illustrates in schematic simplified representation of some basic leadership options for the to be degassed coating medium and on the permeate side 12 fitting or flowing medium 16 , The embodiment of the membrane module 9 can be done in a variety of ways. In the simplest first case, parts of these components of the coating agent guide system form or are integrated in this. Here is the structure of a membrane module 9 reproduced by way of example for a tubular or loop-shaped membrane unit.

The 2a illustrates a first embodiment with an inner tubular or tubular element 18 for guiding to be degassed coating medium 2 , in particular coating color 3 , This is located radially inward and is of a tubular or tubular element 19 to lead a medium 16 enclosed with a lower concentration of gas to be separated in the radial direction and over part of the axial extent. At least a portion of the outer periphery, in particular the wall 20 , preferably the entire surface of the tubular or tubular element 18 is from one or more membranes 7 educated. It is also conceivable the possibility of a plurality of spaced-apart individual membranes, which are connected to each other via other non-permeable elements. The membrane module 9 includes an inlet 13 for the coating medium to be degassed 2 and at least one procedure 14 for the stripping medium depleted of the permeate, the retentate R and also an inlet 21 for medium with a lower concentration of gas to be separated off. This is due to the permeate side 12 on or is guided along this. The transport of the permeate P takes place through the membrane 7 in the medium with a lower concentration of a gas, the nature of the gas to be separated 10 equivalent. The removal of the permeate P takes place together with the order of the separated gas 10 enriched medium via a drain 22 , The leadership of the to be degassed coating medium 2 and the applied on the other side of the membrane medium takes place here in cavities which are arranged coaxially to each other. It would also be conceivable to guide along plates or other shaped membranes.

The feeds 13 . 21 and processes 14 . 22 for the individual media are arranged here so that the membrane module operates in the DC principle, that is, all currents are rectified.

In contrast clarifies 2 B according to an embodiment according to 2a a possible design with countercurrent principle. In this case, the feeds 12 and 21 by way of example on different faces 25 . 26 of the membrane module 9 arranged and directed by these flows are opposite. The same applies to the withdrawals.

Clarify the 2a and 2 B Versions with an internally guided flow of coating color 3 or to be degassed coating medium 2 , illustrate the contrast, the 2c and 2d schematized further embodiments by way of example for the formation of tubular or tubular membrane modules 9 with externally guided to be degassed coating medium 2 , In the in the 2a and 2 B illustrated embodiment, the transport takes place via the membrane from the inside to the outside, in the embodiments according to the 2c and 2d from the outside to the inside. The direction is determined by the partial pressure difference between the permeate side 12 and inflow side 11 specified.

According to 2c In this case, the individual streams - to be degassed coating medium 2 and the medium containing the lower concentration of medium to be separated is passed through the unit in the DC principle, while 2d this works on the countercurrent principle. In the first case, the medium containing the gas to be separated in the lower concentration is guided inside and on its outer periphery around the coating medium to be degassed 2 , Accordingly, the feeds 13 . 21 and the processes 14 . 22 arranged for the individual media. In the DC principle, there are the feeds 13 . 21 preferably in the region of the same end face of the membrane module 9 while countercurrent, as in 2d shown, the individual inflows and outflows as in 2 B described, are arranged on different end faces.

The in the 2a to 2d illustrated embodiments represent particularly advantageous embodiments, which are characterized by the provision of very large contact surfaces due to the formation of these extending in the circumferential direction surfaces. Conceivable, however, are modifications that also for the 2a to 2d can be applied, in which only portions of the circumferentially formed surfaces, which are usually formed by partitions or partitions, with membranes or other geometries of membranes, for example in plate or mat form.

Regarding the usable membrane units can from the prior art a variety of designs resorted become. Preferably, the membranes in the form of hoses, tubes or Hollow fibers constructed in which the to be degassed coating medium is led outside and the receiving medium within. In principle, it is synonymous conceivable to guide the medium to be degassed within, and the receiving medium outside. Important is next to the specified particle pressure difference and the Residence time, in particular contact time with the membrane. This can on the one hand by increasing the peripheral surface be realized, for example, by increasing the dimensions of Inner circumference of the leading to be degassed coating medium Elements inside guided Coating medium or externally guided to be degassed coating medium by enlargement of the outer circumference as well as an enlargement in axial direction. Both measures can be carried out in parallel or separately from each other.

3 illustrates in a highly schematic representation of the basic structure of a membrane deaerator preferably used for degassing of coating color 8th in the form of a membrane module 9 , which as a hollow fiber module 26 is executed. This comprises a plurality of preferably substantially axially parallel to each other arranged hollow fibers 27 on the front ends 23 and 24 for example, in each case at least one chamber 28.1 respectively. 28.2 forming elements 29 are poured in and with these chambers 28.1 . 28.2 are fluidically coupled. About the chambers 28.1 . 28.2 the coupling of the hollow fibers takes place 27 with the feed 21 for the at the permeate side 12 fitting medium 16 and the process 22 for the medium enriched by the permeate P. The advantage of such a module 9 is that no separate Permeatableitung and support structure are required and further by the through the hollow fibers 27 provided large surfaces a long residence time or contact time of the degassed coating medium 2 can be provided with the membrane surfaces. The stripping medium to be degassed 2 flows around the hollow fibers 27 from the outside. The hollow fibers 27 are in a flow chamber for the to be degassed coating medium 2 arranged. Preferably, this is from a housing 30 of the membrane module 9 formed, which for this purpose also at least one inlet and outlet 13 . 14 having. The flow takes place in a cocurrent or countercurrent principle.

For example, there are currently available membrane modules 9 for use. Such a membrane module 9 is preferably used for degassing coating color 3 in a paint delivery system 31 at any point in the guidance system 32 , especially integrated pipe system. It is also conceivable integration in containers, but here is always to ensure that the membrane is also contacted by the to be degassed coating medium. It would also be conceivable to make the wall or the wall region forming the membrane correspondingly displaceable.

The Membrane unit can either as the sole degassing be used or in combination with other methods, in particular the previous vacuum ventilation, to further reduce gas content.

According to a particularly advantageous embodiment, when using a membrane ventilator 8th in combination with the vacuum venting of these preferably in the paint delivery system 31 after vacuum venting 33 arranged. Here are only small gas contents from the coating color 3 that are difficult to separate with other methods. The 4 illustrates exemplified this particularly preferred arrangement in a color delivery system 31 for a commissioned work 34 for coating color 3 , The color delivery system 31 includes at least one work container 35 or a workbench, in which coating color 3 located. The coating medium is a vacuum ventilator by means of a pumping device, not shown here 33 fed. This includes a container 36 which is preferably closed at the top and has a conical shape. Furthermore, this is an inlet 37 associated with which with the working container 35 at least indirectly coupled, preferably directly via corresponding coating color leading piping. The supplied coating medium 2 , in particular the coating color 3 , Is then first spent on a driven with a drive machine turntable, from which the coating medium runs down into the apex. The coating color is partially vented when hitting the turntable. The vacuum in the container is generated by a corresponding vacuum pump. The membrane module 9 is then the exit from the vacuum fan 33 downstream and the commissioned work 34 upstream. Since in non-porous membranes only dissolved gas contained in the coating medium can be separated, it is important that sufficient dissolved gas is present at the appropriate location. For example, free gas can be converted into dissolved gas by increasing the pressure in the pipeline (pressure and temperature-dependent equilibrium). In many places is the pressure in the paint delivery system 31 already high enough to shift the balance towards the dissolved gas.

Is it enough to reduce the gas content with one module? 9 not enough, it is conceivable to arrange and use several individual modules in parallel or else in series. This is exemplary in 5 shown. There is the to be degassed coating medium 2 via a conveying device, in particular a pump of a membrane system 38 supplied, which consists of a plurality of parallel or serially arranged individual modules 1 to 6. This includes, by way of example, three separation stages I, II, III. In the first separation stage, the coating medium to be degassed becomes 2 parallel, ie divided into material streams simultaneously fed to three modules module 1 to module 3. The denoted in each separated permeate P, for the individual modules with P1 to P3, is deposited or transported away. Each of the permeate P1 to P3 depleted streams of gas to be degassed coating medium 2 , which are referred to as Renetatströme R1 to R3, are fed to a second separation stage II, which is in series with the first, ie downstream of this and consists of two modules, the module 4 and module 5 by way of example. There, the permeates P4 and P5 are separated and the remaining renetates R4 and R5 are fed to a further separation stage III from a module 6. The present after leaving the module 6 present to the permeate P1 to P6 depleted to be degassed coating medium 2 is then present as Renetat R and has after passing through the individual separation stages I to III no or only a minor proportion of dissolved gas. This can then when using the membrane unit in a paint system 31 for commissioned works the latter are supplied.

ever after construction of the individual modules and the guiding directions of the coating medium to be degassed, of the permeate or the carrier medium for the Permeate and / or the coupling of the individual modules with each other can the individual modules, sections of the system and the entire Plant according to specification according to the DC, counter or cross-countercurrent principle operate.

Preferably, the membrane degassing apparatus becomes 9 operated with the following media: The medium with the high concentration of the gas to be removed is formed by the coating color, while the medium with the low concentration of the gas to be removed is preferably a vacuum, an inert gas or a gas-free liquid. As a liquid medium, for example, water is conceivable, which is previously freed of gas by vacuum or temperature increase, especially boiling. To In turn, appropriate treatment facilities for the gas-free liquid-forming liquid are required.

1

contraption

2

coating medium

3

coating color

4

Streichfarbeentgasungsvorrichtung

5

subregion

6

wall

7

membrane

8th

Membranentgasungsvorrichtung

9

membrane module

10

gas

11

inflow

12

permeate

13

Intake

14

procedure

15

surface

16

medium

17

permeate outlet

18

pipe- or tubular element

19

pipe- or tubular element

20

outer periphery

21

Intake

22

procedure

23

front

24

front

26

Hollow fiber module

27

hollow fiber

28.1, 28.2

chamber

29

element

30

casing

31

Color provisioning system

32

pipe system

33

Vacuum-

34

commissioned

35

working container

36

container

37

Intake

38

membrane plant

P

permeate

R

retentate

Claims (30)

Process for degassing a liquid or pasty coating medium ( 2 ) for application in a commissioned work on a fibrous web, in particular a paper or board web, characterized in that in the to be degassed coating medium ( 2 ) contained gas ( 10 ) via at least one membrane ( 7 ) is deposited in the presence of a partial pressure difference and the membrane ( 7 ) penetrates. Method according to claim 1, characterized in that the coating medium to be degassed ( 2 ) on an inflow side ( 11 ) of the membrane ( 7 ) and the partial pressure difference across the membrane ( 7 ) by concentration differences of the gas to be separated ( 10 ) on the membrane sides facing away from each other - the inflow side ( 11 ) and the permeate side ( 12 ) opposite the outlet side for the permeate (P) - is generated, wherein the concentration of the gas to be separated ( 10 ) in the coating medium to be degassed ( 2 ) on the upstream side ( 11 ) of the membrane ( 7 ) higher than at the permeate side ( 12 ). Process according to claim 1 or 2, characterized in that on the permeate side ( 12 ) a vacuum is applied. Method according to at least one of the preceding claims, characterized in that on the permeate side ( 12 ) of the membrane ( 7 ) a gaseous medium ( 16 ) is applied or guided as a carrier medium for the permeate, which is preferably similar to the species to be separated from the gas ( 10 ) in the coating medium to be degassed ( 2 ). Process according to claim 2 or 3, characterized in that on the permeate side ( 12 ) of the membrane ( 7 ) a liquid medium ( 16 ), which is free of gas or characterized by a low gas concentration, is applied or guided. Method according to one of claims 1 to 5, characterized in that the permeate (P) after leaving the membrane ( 7 ) from the permeate side ( 12 ) is rinsed away or sucked off by a vacuum. Method according to one of claims 1 to 6, characterized in that the permeate (P), the stripping medium depleted of the permeate ( 2 ) and the coating medium to be degassed ( 2 ) in the cross-countercurrent principle along the membrane ( 7 ). Method according to one of claims 1 to 7, characterized in that dissolved and / or free gas through the membrane ( 7 ) is deposited. Method according to claim 8, characterized in that the proportion of dissolved gas ( 10 ) in the coating medium to be degassed ( 2 ) at least in the contact region of the membrane ( 7 ) is controlled. A method according to claim 8 or 9, characterized in that free gas in the stripping medium to be degassed ( 2 ) by pressure and / or temperature change in dissolved gas ( 10 ) is converted. Method according to one of claims 1 to 10, characterized in that a membrane ( 7 ) is used from a hydrophobic material. Method according to one of claims 1 to 11, characterized in that the degree of separation of permeate (P) by at least one of the following variables is influenced: - type of membrane material used - dimensioning of the membrane ( 7 ), in particular thickness and size of the effective area - contact time of the coating medium to be degassed ( 2 ) with the membrane ( 7 ) - partial pressure difference across the membrane ( 7 ) Method according to one of claims 1 to 12, characterized in that membranes ( 7 ) are used in the form of hollow fibers or capillaries. Method according to one of claims 1 to 13, characterized in that one or more membranes ( 7 ) to a membrane module ( 9 , Modules 1 to 6) and a stream of stripping medium to be degassed ( 2 ) and over a plurality of parallel modules (module 1 to module 3, module 4 and 5) is performed. Method according to one of claims 1 to 14, characterized in that one or more membranes ( 7 ) to a membrane module ( 9 , Module 1 to 6) are summarized and the to be degassed coating medium ( 2 ) is guided in a plurality of successively arranged separating stages (I, II, III) via a plurality of modules connected in series with one another. Contraption ( 1 ) for degassing a liquid or pasty coating medium ( 2 ) for application to a fibrous web, in particular paper or board web, in one, a commissioned work ( 34 ) upstream color supply system ( 31 ), characterized in that it is used as a membrane degassing device ( 8th ) is executed. Contraption ( 1 ) according to claim 16, characterized in that the membrane degassing device ( 8th ) at least one membrane ( 7 ) comprising at least a partial surface of a boundary wall in a guide system ( 32 ) for the coating medium to be degassed ( 2 ). Contraption ( 1 ) according to claim 16 or 17, characterized by the following features: 18.1 a plurality of membranes ( 7 ) are to a membrane module ( 9 ) summarized; 18.2 the membrane module ( 9 ) comprises at least one entrance ( 13 ) for coating medium to be degassed ( 2 ), an outlet for the stripping medium to be degassed around the permeate (P) ( 2 ) as a retentate (R) and an exit for the permeate (P). Contraption ( 1 ) according to claim 18, characterized in that the membrane module ( 9 ) at least one input ( 21 ) for the outlet side of the membrane designated as permeate side (P) ( 7 ) acting as a carrier medium medium ( 16 ) and a process ( 22 ) for the permeate side ( 12 ) designated outlet side on the membrane ( 7 ) attached medium ( 16 ) and the permeate (P). Contraption ( 1 ) according to one of claims 17 to 19, characterized in that the at least one membrane ( 7 ) consists of a hydrophobic material. Contraption ( 1 ) according to one of claims 17 to 20, characterized in that the at least one membrane ( 7 ) consists of a porous material. Contraption ( 1 ) according to one of claims 17 to 21, characterized in that the individual membrane ( 7 ) is based on one of the following materials: - Polysiloxanes and their derivatives - Polytetrafluoroethylene and derivatives - Polyolefins and their derivatives Device according to one of claims 17 to 22, characterized in that the individual membrane ( 7 ) is flexible. Contraption ( 1 ) according to claim 23, characterized in that the individual membrane ( 7 ) is mat-shaped or tubular. Device according to one of claims 17 to 22, characterized in that the individual membrane ( 7 ) is rigid. Contraption ( 1 ) according to claim 25, characterized in that the individual membrane ( 7 ) is designed plate-shaped or tubular. Contraption ( 1 ) according to one of Claims 17 to 26, characterized in that the individual membrane ( 7 ) in the form of hollow fibers ( 27 ) is executed. Contraption ( 1 ) according to claim 29, characterized in that the membrane module ( 9 ) is designed as a hollow fiber module, comprising a plurality of substantially parallel to each other axially parallel hollow fibers ( 27 ), of the to be degassed coating medium ( 2 ) are flow around, the hollow fibers ( 27 ) with an outlet for permeate ( 10 ) and the medium ( 16 ) are connected. Paint delivery system ( 31 ) for an up work ( 34 ) for refining running fibrous webs, in particular a curtain applicator, comprising at least one working container ( 35 ), with an outlet from the working container ( 35 ), characterized in that at least one device ( 1 ) is provided for degassing according to one of claims 16 to 28. Paint delivery system ( 31 ) according to claim 29, characterized in that this is a vacuum ventilator ( 33 ) connected to an outlet from the working container ( 35 ), and the device ( 1 ) the vacuum fan ( 30 ) is subordinate.