DE102008023792B4 - Arrangement for film casting - Google Patents

Abstract

Arrangement for film casting with a slot die, a rotating casting roll and a take-off roll, which is arranged opposite to the circumferential direction of rotation of the rotating casting roll in a short circumferential distance in front of the slot nozzle, whereby a free-running in casting operation area of the casting roll peripheral surface is given while the larger area of the casting roll peripheral surface remaining through the remaining long circumferential distance between the slot die and the take-off roll is looped during operation by the resulting film, characterized in that the following features are provided: a) in the free area of the casting roll Peripheral surface (6) is at least one resting on this movable cleaning tool in the form of a flexible linear member (11; 21a, b; 22a, b) arranged as a band, rope or string of liquid impregnated with cleaning fluid material; b) the longitudinal direction (12) of the movable linear member (11; 21a, b; 22a, b) is transverse to the circumferential direction (4) of the rotating casting roll (2); c) the flexible linear member (11; 21a, b; 22a, b) is movably guided in its longitudinal direction (12) and driven so as to be moved beyond the lateral edge of the casting-roll peripheral surface (6); d) the flexible linear member (11; 21a, b; 22a, b) is guided in its longitudinal direction on a stationary strip-like guide member (10), wherein its lateral abutment on the guide member (10) is effected by that of the moving casting rolls Peripheral surface (6) is dragged by friction; e) the strip-like guide part (10) has an open longitudinal groove (23) for receiving the flexible linear member (11; 21a, b; 22a, b).

Description

The invention relates to an arrangement for film casting with a slot die, a rotating casting roll and a take-off roll, which is arranged opposite to the circumferential direction of rotation of the rotating casting roll in a short circumferential distance in front of the slot nozzle, whereby a remaining in the continuous casting operation range of Gießwalzen- Peripheral surface is given while the remaining by the remaining long circumferential distance between the slot and the take-off roller larger area of the casting roll peripheral surface is looped during operation of the resulting film, according to the preamble of claim 1.

An arrangement of this kind is known from the German patent DE 12 54 856 B known. In this case, an extruded plastic material, for example a molten thermoplastic film-forming polymer, emerges from the slot die in a thin layer with a temperature between about 200 ° C. (polyamide) to 280 ° C. (polyethylene terephthalate, PET) and more and reaches the cooled one Peripheral surface of the casting roll. In the case of the quenching and cooling process due to the temperature difference, the film web forms on the casting roll peripheral surface and is finally drawn off from the casting roll with a take-off roll. The film web resting on the casting roll circumferential surface wraps around the casting roll corresponding to a circumferential angle of 240 ° to 280 °. Between the slot nozzle and the take-off roll only a small area remains corresponding to a circumferential angle of at most 80 ° to 120 °, which remains free in the current casting operation, so is not wrapped by the film web.

During casting of the film webs, and especially during dry processes, particles are formed, the so-called oligomers, which precipitate on the casting roll as white polymer dust. In particular, these deposits affect the exposed lateral edge areas of the casting roll peripheral surface adjacent to the film web, which maintains a distance from the side surfaces of the casting roll. Leaving it in the deposits, the film web soiled in their peripheral areas, especially if the width of the film webs produced is varied. If necessary, the edge regions of the film webs must be cut off and disposed of as waste. To a lesser extent, however, the central area of the casting roll circumferential surface is affected by the pollution. The removal of the polymer dust is an urgent problem when casting the film webs.

The WO 98/22652 A1 describes a device for cleaning a moving surface, in which stripping elements, which are lined up on a chain, are guided past the surface to be cleaned. The stripping elements have a blade-like edge. Also the FR 2474899 A1 teaches the use of a scraper element with a blade edge for cleaning a roller surface. The removal of fine dusty substances from the sensitive surface of a casting roll is not possible with blade-like scraper elements. The DE 3810085 A1 shows a device with a driven brush which is movable across a roll surface. This device is relatively expensive, since additional equipment is required to drive and to clean the brush. The US 5842418 A discloses the use of a cleaning pad which is pressed against the surface of a roller. If the cleaning pad gets dirty, the system must be shut down and the cleaning pad cleaned or replaced.

From practice, various proposals for regular cleaning of the casting roll circumferential surface have become known. A side blow with compressed air has proved ineffective and even harmful. According to another method, the casting operation was interrupted, the casting roll stopped and washed off its peripheral surface with water and then rubbed dry. The disadvantage here is the interruption of the casting operation and the time-consuming method of cleaning. Furthermore, attempts have been made to clean the free edge areas of the casting-roll peripheral surface in the ongoing casting operation by means of cleaning wipes or bodies, the so-called pads. A disadvantage proved to be that no cleaning liquid can be used because it pollutes too quickly and can not be replaced. It is also desirable to clean the casting roll circumferential surface not only in their peripheral areas, but in total. This is counteracted, however, that the casting roll peripheral surface with its entire width only in the already mentioned small area corresponding to a circumferential angle of at most 60 ° during operation is completely open and is accessible for cleaning.

The invention is therefore based on the object, an arrangement of the type mentioned in such a way that the casting roll peripheral surface can be effectively cleaned during operation, the polluting particles not only solved by the casting roll peripheral surface, but also effective from the field of Casting roller to be removed.

• a) in dem frei bleibenden Bereich der Gießwalzen-Umfangsfläche ist mindestens ein auf dieser aufliegendes bewegliches Reinigungswerkzeug in der Form eines flexiblen Lineargliedes als Band, Seil oder Schnur aus mit Reinigungsflüssigkeit tränkbarem Material angeordnet;
• b) die Längsrichtung des beweglichen Lineargliedes verläuft quer zu der Umfangs-Laufrichtung der rotierenden Gießwalze;
• c) das flexible Linearglied ist in seiner Längsrichtung beweglich geführt und derart angetrieben, dass es bis über den seitlichen Rand der Gießwalzen-Umfangsfläche hinaus bewegt wird.
• d) das flexible Linearglied ist in seiner Längsrichtung an einem stationären leistenartigen Führungsteil geführt, wobei seine seitliche Anlage an dem Führungsteil dadurch zustande kommt, dass es von der bewegten Gießwalzen-Umfangsfläche durch Reibung mitgenommen wird.
• e) das leistenartige Führungsteil weist eine offene Längsnut zur Aufnahme des flexiblen Lineargliedes auf.

This object is achieved according to the invention in an arrangement according to the preamble of claim 1, that according to the characterizing part of claim 1, the following features are provided:

• a) in the remaining free area of the casting roll peripheral surface at least one resting on this movable cleaning tool in the form of a flexible linear member as a band, rope or cord from impregnated with cleaning liquid material is arranged;
• b) the longitudinal direction of the movable linear member is transverse to the circumferential direction of rotation of the rotating casting roll;
• c) the flexible linear member is movably guided in its longitudinal direction and driven so that it is moved beyond the lateral edge of the casting roll circumferential surface.
• d) the flexible linear member is guided in its longitudinal direction on a stationary strip-like guide member, wherein its lateral abutment on the guide member is effected by the fact that it is driven by the moving casting-roller peripheral surface by friction.
• e) the strip-like guide member has an open longitudinal groove for receiving the flexible linear member.

According to the invention, at least one cleaning tool is thus provided in the form of a flexible linear member. This thus has the basic shape of a string or a band and is moved transversely to the circumferential direction of rotation of the rotating casting roll on the cylindrical peripheral surface. The term "transverse" not only means "strictly vertical", but also does not include too large angular deviations from the strictly vertical orientation relative to the circumferential direction with a. Angular deviations of 30 ° on both sides are included in each case.

The flexible linear member requires in the direction of the circumferential direction of rotation of the rotating casting roller only little space and can therefore be readily installed in the non-looped by the film web, so free region of the casting-circumferential surface. In this case, even the arrangement of several flexible linear members one behind the other in the running direction of the casting roll peripheral surface is possible. With appropriate lateral guidance, the flexible linear member can be easily moved on the casting roll circumferential surface even when the casting roll rotates; the casting operation must therefore not be interrupted for cleaning the casting roll. By the flexible linear member is moved beyond the lateral edge of the casting roll peripheral surface, it not only takes the polluting particles, but also transports them from the region of the casting roll to the outside, where they possibly together with the flexible linear member without affecting the Cleaning process can be disposed of easily.

The cleaning operation with the flexible linear member can be continuous or discontinuous, in any case, during the casting operation. For example, during the casting operation, the flexible linear member may be moved incrementally at intervals with pauses therebetween. Or it is continuously moved once during the casting operation for a certain length of time. Furthermore, an automatic activation of the cleaning operation in dependence on the metrological detection of the particle seizure is possible.

Advantageous developments of the arrangement according to the invention are listed in the dependent claims.

Concretely, the flexible linear member may be a band, a cable, a rope, a string or a chain, only its cleaning effecting portion being made of a lint-free material. The rule "lint-free" means that the cleaning material itself should not leave any traces or residue.

It is advantageous if the cleaning effecting area consists of a microfiber material. In that case, the flexible linear member itself is most easily produced completely from the microfiber material.

It is also possible that the flexible linear member is a flexible brush belt with a suction. In this case, however, care must be taken to ensure that this brush tape loses no bristles. Advantageously, such a flexible brush belt may be a precursor to a cleaning in which a flexible linear member made of a microfiber material is provided as the second stage.

The flexible linear members can be used in the dry state or in conjunction with a liquid cleaning agent.

The greatest possible provision against contamination in the cleaning process itself is given when a supply and a take-up reel are provided and the flexible linear member has a finite length, being unwound during the cleaning process of the supply reel and wound onto the take-up reel. In this embodiment, the recorded polluting particles are disposed of together with the flexible linear member outside of the casting roll, so that no harmful reaction to the cleaning process is possible.

In principle, however, it is also possible that the flexible linear member has a closed endless shape and is continuously circulated over the casting roll peripheral surface, wherein on the return path from the casting roll circumferential surface is interposed a cleaning station. In this embodiment, the flexible linear member can remain in use for a long time. However, a precondition for proper functioning is that the intermediate cleaning station works perfectly.

If, in the arrangement according to the invention, the flexible linear member is to be used in conjunction with a liquid cleaning agent, then a first possibility for applying the cleaning liquid is that a submersible bath container with a cleaning liquid is provided in the inflow of the flexible linear member to the casting roll peripheral surface the flexible linear member is soaked with the cleaning liquid. This type of execution has the advantage of a relatively simple construction; but it must be ensured that the flexible linear member is not soaked in excess with the cleaning liquid.

Another possibility for applying the cleaning liquid is that in the circumferential direction of rotation of the rotating casting roll in front of the flexible linear member and extending parallel to this a manifold is arranged, which emits a liquid detergent to the casting roll peripheral surface and the flexible linear member. There is a wide choice for the detergent itself. Preference is given to water, alcohol or a mixture of the two. From the distributor pipe, the cleaning liquid is to be carried out either on the casting roll peripheral surface or on the flexible linear member and at the same time on both. This second possibility for applying a cleaning agent has the advantage that the amount of cleaning agent to be applied can be kept smaller and therefore the subsequent drying is easier. Possible is an embodiment with a series of nozzles on a manifold, the punctiform and adjustable deliver small amounts of cleaning fluid.

If such a distributor pipe is provided with the finely metered release of a cleaning agent, it may be expedient to connect an air knife to the flexible linear member in the circumferential running direction of the rotating casting roll. With this then a drying air flow is promoted to the remaining free area of the casting roll peripheral surface.

For the flexible linear member, the lateral guidance is important because it must be cleaning on the moving casting roll circumferential surface. Provided is a guide on a stationary strip-like guide part, on which the flexible linear member bears laterally. The plant is due to the fact that the flexible linear member is entrained by the casting roll peripheral surface in the casting operation by friction.

The strip-like guide member has an open longitudinal groove for receiving the flexible linear member, wherein the profile of the longitudinal groove may be shaped such that the flexible linear member additionally receives a force component for engagement with the casting roll peripheral surface.

A simple embodiment of the arrangement according to the invention may consist in that a single flexible linear member is provided, the working range of which extends over the entire axial width of the casting-roll peripheral surface. However, the flexible linear member absorbs polluting particles already in the first edge region, which particles can then interfere even if the particles in the opposite edge region are to be removed or taken away.

An improved embodiment is therefore that two flexible linear members are arranged with opposite direction of movement, wherein the cleaning movement takes place on the casting roll peripheral surface from the inside to the outside. The working areas of the two flexible linear members in the axial direction of the casting-roll peripheral surface can thereby adjoin one another or overlap in regions. The purpose of this design is that the flexible linear members move outwardly from the less soiled center region of the casting roll peripheral surface, so that in the more heavily fouled edge region of the casting roll peripheral surface the flexible linear member is even more receptive.

In a further development of this idea, the working areas of the two flexible linear members can also be separated from each other and each extend only over one of the two axial edge regions of the casting roll peripheral surface. The marginal areas over which the working area of each linear member extends are slightly wider than the lateral areas not covered by the film web. In this case, a special cleaning of the central region of the casting roll peripheral surface is dispensed with.

Finally, it is also possible that in the circumferential direction of the casting roll peripheral surface successively two flexible linear members are arranged, of which the first works in the dry state and the second in conjunction with a liquid detergent. This double arrangement is possible if the working width of a flexible linear member extends over the entire axial width of the casting roll or only over a partial region.

A further advantageous embodiment of the arrangement according to the invention is directed to the fact that the components used for cleaning are combined to form a separate assembly which can be lifted as a whole from the casting-roll peripheral surface.

The components of such an assembly include the at least one flexible linear member and the corresponding strip-like guide member, the supply and take-up reel with motor drive and pulleys, possibly a dip tank or manifold for the cleaning fluid and an air knife, all this together with the corresponding connecting parts and connecting cables.

Such an assembly may be arranged on a single carrier, the z. B. by means of a servomotor or a hydraulic device radially to the casting roll peripheral surface is linearly movable or pivotable. With such a construction, the assembly with the cleaning components can be removed from the casting roll peripheral surface in the fastest way when a disturbance of the casting operation occurs, for example, by forming lumps or cracks from the film web. This avoids that the sensitive and very expensive casting roll is damaged in the event of a malfunction.

The invention will be explained in more detail with reference to embodiments which are illustrated in the figures. In the figures, the following is shown:

1 is the spatial representation of an inventive arrangement for film casting, in which the casting roll surface is cleaned with a flexible linear member.

2 shows one too 1 belonging side view.

3 is the spatial representation of one of 1 corresponding arrangement according to the invention, are additionally attached to a manifold for a cleaning fluid and an air knife.

4 represents in a 1 and 3 corresponding representation of a modified embodiment of the inventive arrangement.

5 shows a further modification to the embodiment according to 4 ,

6a is one of the 5 corresponding representation of an arrangement in which an additional immersion bath container is provided with a cleaning liquid.

6b shows at the location of Tauchbadbehälters a manifold with otherwise identical representation.

7 shows a particular embodiment of the arrangement according to the invention, in which the functional parts used for cleaning the casting roll surface are combined to form a device which can be lifted as a whole from the casting roll.

In 1 an arrangement for film casting is shown, which with a slot nozzle 1 , a casting roll 2 and a take-off roll 3 Is provided. During operation, the casting roller rotates 2 with a circumferential direction 4 according to the casting roll rotation direction 5 ( 2 ) around its central axis. In this case, a thin layer of extruded plastic material emerges from the slot nozzle 1 from and reaches the casting roll peripheral surface 6 , While the extruded plastic material may have a temperature of 230 ° C and more depending on its composition as it exits the slot die, the casting roll is 2 cooled from the inside, so that the casting roll peripheral surface 6 during operation has a surface temperature of about 45 ° C.

The layer of the extruded plastic material therefore undergoes a quenching process and becomes the film web 8th converted onto the moving casting roll peripheral surface 6 rests and is taken by this, until finally by means of the take-off roller 3 from the casting roll peripheral surface 6 lifted and as discontinued film web 8th in the withdrawal direction 9 their further processing is supplied.

The 2 points in the direction of the side surface 7 the casting roll 1 in that the casting roll peripheral surface 6 by far the largest part of its scope of the film web 8th is entwined. In the illustrated embodiment, the vacant area corresponds to the casting roll peripheral surface 6 that of the film web 8th is not wrapped, a circumferential angle α of the casting roll of about 45 °, while that of the film web 8th looped area caused by the long circumferential distance between slot nozzle 1 and take-off roll 3 is given, corresponds to a circumferential angle β of 315 °. The features of the inventive arrangement described hitherto are customary in the art. It is used to cast flat films in a dry thermal process. This inevitably results in particles (oligomers), which can be found as dust or powder in the casting roll 1 drop. In particular, of these are the remaining free lateral areas 25 the casting roll 1 not affected by the film web 8th are covered. To a lesser extent, however, also contaminates the through the film web 8th covered area.

To remove the particles is therefore in accordance with the 1 to 3 a movable cleaning tool in the form of a flexible linear member 11 intended. It is in the of the film web 8th not wrapped, so in operation free area of the casting rolls peripheral surface 6 arranged, which is defined by the circumferential angle α. The flexible linear member 11 lies with a certain bearing force on the casting roll peripheral surface 6 on and is in its longitudinal direction 12 movably powered. Its longitudinal direction 12 is thus at the same time its direction of movement. The longitudinal and direction of movement 12 The flexible linear member extends transversely to the circumferential direction 4 the casting roll 2 , The term "transverse" should not only mean "strictly vertical", but also can not be too large angle deviations from the strictly vertical orientation relative to the circumferential direction 4 include. Angular deviations of 30 ° on both sides are included in each case.

The flexible linear member 11 is a rope or a string, but can also be a band. In its cleaning effecting area, with which the flexible linear member 11 on the casting roll peripheral surface 6 rests, consists of the flexible linear member 11 in any case made of a lint-free material. Preferred is a microfiber material that is optimally adapted to the purpose of receiving and entraining particles. The illustrated in the figures of the embodiments flexible linear member 11 should consist entirely of a microfiber material.

The flexible linear member 11 becomes in its longitudinal and moving direction 12 driven to a linear motion. According to the embodiments of the 1 and 3 passes over the flexible linear member 11 the entire width of the casting roll 2 from the right edge to beyond the left edge. It absorbs the polluting particles and carries them away from the casting roll peripheral surface 6 ,

The linear alignment of the longitudinal and direction of movement 12 comes about by the flexible linear link 11 on a strip-like guide part 10 is guided. This is stationary over the casting roll peripheral surface 6 attached and in the direction of the casting roll peripheral surface 6 back and opposite to their direction 4 with an outwardly open longitudinal groove 23 provided, cf. the detail A too 2 , The longitudinal groove 23 has a cross-section that decreases from its opening to its end. In the illustrated embodiment, the cross section is curved in the manner of a circular arc or an ellipse. This design of the longitudinal groove means that during operation, the flexible linear member 11 from the circumferential casting roll peripheral surface 6 in the circumferential direction 4 taken along and in longitudinal groove 23 is pulled into it. It is thus oriented in the longitudinal direction of the strip-like guide part 10 out. Because the contour of the cross section of the longitudinal groove 23 curved, receives the flexible linear member 11 at the same time a force component, it against the casting roll peripheral surface 6 suppressed.

After the 1 and 3 are flexible linear links 11 of finite length provided. In both cases, there is the clean, in its initial state located flexible linear member 11 on a supply spool 13 ; from there it will be over a first pulley 14 across the casting roll peripheral surface 6 and from there via a second pulley 15 to a take-up reel 17 guided. When the entire stock length of the flexible linear member 11 along with the entrained particles on the take-up spool 17 are wound up, both coils are 13 and 17 renewed. The motor drive of such coils is customary and need not be discussed particularly.

The cleaning operation with the flexible linear member 11 can be continuous or discontinuous, in any case, even during the casting operation. For example, the flexible linear member 11 during the casting operation are moved stepwise at intervals with intervening pauses. Or it is continuously moved once during the casting operation for a certain length of time. Furthermore, an automatic activation of the cleaning operation in dependence on the metrological detection of the particle seizure is possible.

In the arrangement according to the 1 Dry cleaning is performed by the flexible linear member 11 , After the in 3 embodiment shown is the flexible linear member 11 a fixedly mounted distribution pipe 19 upstream. It is used to deliver a liquid detergent, for which there is a large choice. Preference is given to water, alcohol or a mixture of the two. If the polluting particles consist of polymer dust, namely condensed oligomers, their adhesion to the casting roll peripheral surface may 6 already be lifted by means of water. The condensed oligomers do not dissolve with the water, but are merely purified with water.

From the manifold 19 the cleaning liquid should either to the casting roll peripheral surface 6 or to the flexible linear member 11 or simultaneously to both. The delivery should be finely dosed. For this purpose, a number of nozzles on the manifold 19 be attached, the punctiform and adjustable deliver small amounts of cleaning fluid.

In 3 is in the circumferential direction 4 the casting roll peripheral surface 6 behind the strip-like guide part 10 with the flexible linear member 11 an air knife 20 arranged, which a drying air flow on the remaining free area of the casting roll peripheral surface 6 promotes. In this way, a stage of wet cleaning is followed by a stage of dry cleaning.

Another possibility for a two-stage arrangement may be that first a mechanical rough cleaning takes place by using as a flexible linear member 11 a flexible brush belt with suction or a so-called V-belt brush on the casting roll peripheral surface 6 runs and that the brush belt a flexible linear member 11 is followed by a microfiber material.

In the embodiments according to the 4 to 6b has the arrangement of two pairs of cooperating flexible linear members 21a , Federation 22a , b another meaning. The polluting particles, usually a white polymer dust, are mainly found on the free areas 25 the casting roll 2 down, not from the film web 8th are covered. According to 4 are therefore in the vacant area of the casting roll peripheral surface 6 two flexible linear links 11 arranged. Your direction of movement 12a , b is directed in opposite directions and with their cleaning effective areas from inside to outside. The working areas of the two flexible linear links 21a , b cover each other in the longitudinal and direction of movement 12a , b or at least connect to each other. Only because of the space requirement are the two flexible linear members 21a , b also in the circumferential direction 4 offset from each other. Drive and guidance of the two flexible linear links 21a , B are basically the same design as in the embodiments described above, so that the same reference numerals are entered as previously for parts remaining unchanged. In addition, for each of the two flexible linear links 21a , b only a third pulley 16 required.

The advantage of the arrangement according to 4 is that cleaning in the heavily soiled lateral areas 25 always with a flexible linear member 21a , b, which has taken up little dirt and is therefore particularly receptive. In the execution according to the 1 and 3 on the other hand, the particles are from the first cleaned lateral area 25 already on the flexible linear member 11 if this is the opposite side area 25 reached.

A further embodiment of the arrangement according to the invention is in the 5 shown and is that the working areas of the two flexible linear members 22a , b no longer cover or touch each other. Each of the two moving in opposite directions from inside to outside flexible linear members 22a , b merely sweeps over an edge region of the casting roll peripheral surface 6 , Each lateral edge area of one of the flexible linear links 22a , b is swept, has a width B which is greater than the width b of the free lateral area 25 that of the film web 8th is not covered. In this way it is ensured that the edges of the film web can not pollute. In the execution according to the 5 can the two flexible linear links 22a , b with matching longitudinal direction 12a , b are arranged. As a result, the space required despite the installation of two flexible linear links 22a , b decreased again. The direction of travel of the flexible linear links 22a However, b is opposite.

In the variant according to the 6a is in the inlet of the linear member 22a to the casting roll peripheral surface 6 a dip tank 18 with a cleaning fluid 24 arranged.

The flexible linear member 22a goes through the dipping bath and gets with the cleaning liquid 24 soaked. Also in the arrangements according to the 4 to 6 it is possible stations of wet and dry cleaning in the circumferential direction 4 the casting roll peripheral surface 6 to install one after the other. According to 6b is in the place of the dipping bath container 18 a manifold 19 ,

7 shows in a more detailed embodiment than heretofore an arrangement according to the invention, in which the components serving for the cleaning are combined into a separate assembly which as a whole of the casting roll peripheral surface 6 can be lifted. The assembly can therefore move in the fastest way from the casting roll peripheral surface 6 be removed if necessary. This may be necessary in case of disturbances of the casting operation, for example if of the film web 8th Lumps are formed or cracks arise. It is then ensured that the sensitive and very expensive casting roll 2 is not damaged in such malfunctions.

LIST OF REFERENCE NUMBERS

1

slot

2

casting roll

3

off roll

4

Circumferential direction

5

direction of rotation

6

Casting-roll circumferential surface

7

Casting-side surface

8th

sheet

9

Departure direction of the film web

10

strip-like guide part

11

flexible linear member

12, 12a, b

Longitudinal and direction of movement

13

supply spool

14

first pulley

15

second deflection roller

16

third pulley

17

up reel

18

Tauchbadbehälter

19

manifold

20

air knife

21a, b

flexible linear member

22a, b

flexible linear member

23

longitudinal groove

24

cleaning fluid

25

free lateral area

b

Width of the free lateral area

B

axial edge area (working area) according to 5 and 6

α, β

circumferential angle

Claims (16)

Arrangement for film casting with a slot die, a rotating casting roll and a take-off roll, which is arranged opposite to the circumferential direction of rotation of the rotating casting roll in a short circumferential distance in front of the slot nozzle, whereby a free-running in casting operation area of the casting roll peripheral surface is given while the larger area of the casting roll peripheral surface remaining through the remaining long circumferential distance between the slot die and the take-off roll is looped during operation by the resulting film, characterized in that the following features are provided: a) in the free area of the casting roll Peripheral surface ( 6 ) is at least one resting on this movable cleaning tool in the form of a flexible linear member ( 11 ; 21a , b; 22a b) arranged as a band, rope or string of material impregnated with cleaning liquid; b) the longitudinal direction ( 12 ) of the movable linear member ( 11 ; 21a , b; 22a , b) extends transversely to the circumferential direction ( 4 ) of the rotating casting roll ( 2 ); c) the flexible linear member ( 11 ; 21a , b; 22a , b) is in its longitudinal direction ( 12 ) and driven such that it extends beyond the lateral edge of the casting roll peripheral surface ( 6 ) is moved out; d) the flexible linear member ( 11 ; 21a , b; 22a , b) is in its longitudinal direction on a stationary strip-like guide part ( 10 ), wherein its lateral abutment on the guide part ( 10 ) is due to the fact that it depends on the moving casting-roll peripheral surface ( 6 ) is dragged by friction; e) the strip-like guide part ( 10 ) has an open longitudinal groove ( 23 ) for receiving the flexible linear member ( 11 ; 21a , b; 22a , b) on. Arrangement according to claim 1, characterized in that at least the cleaning causing area of the band, the rope or the cord ( 11 ; 21a , b; 22a , b) consists of a lint-free material. Arrangement according to claim 1 or 2, characterized in that the flexible linear member ( 11 ; 21a , b; 22a , b) consists of a microfiber material. Arrangement according to one of claims 1 to 3, characterized in that a supply reel ( 13 ) and a take-up spool ( 17 ) are provided and the flexible linear member ( 11 ; 21a , b; 22a , b) has a finite length, wherein it is in the cleaning process of the supply reel ( 13 ) and on the take-up spool ( 17 ) is wound up. Arrangement according to one of claims 1 to 3, characterized in that the flexible linear member has a closed endless shape and is continuously circulated over the casting roll peripheral surface, wherein on the way back from the casting roll peripheral surface, a cleaning station is interposed. Arrangement according to one of claims 1 to 5, characterized in that in the inlet of the flexible linear member ( 22a , b) to the casting roll peripheral surface ( 6 ) a dip tank ( 18 ) is provided with a cleaning liquid, in which the flexible linear member ( 11 ; 21a , b; 22a , b) is impregnated with the cleaning liquid. Arrangement according to one of claims 1 to 6, characterized in that in the circumferential direction ( 4 ) of the rotating casting roll ( 2 ) in front of the flexible linear member ( 11 ) and parallel to this running a manifold ( 19 ) is arranged, the a liquid cleaning agent to the casting roll peripheral surface ( 6 ) and to the flexible linear member ( 11 ; 21a , b; 22a , b) surrenders. Arrangement according to one of claims 1 to 6, characterized in that the flexible linear member ( 11 ) in the circumferential direction ( 4 ) of the rotating casting roll ( 2 ) an air knife ( 20 ), which directs a drying air flow onto the remaining area of the casting roll circumferential surface (FIG. 6 ) promotes. Arrangement according to claim 7 or 8, characterized in that the distributor pipe ( 19 ) and the air knife ( 20 ) over the entire working width of the flexible linear member ( 11 ). Arrangement according to one of claims 1 to 9, characterized in that the longitudinal groove ( 23 ) against the circumferential direction ( 4 ) of the casting roll peripheral surface ( 6 ) open to this and is shaped such that the flexible linear member ( 11 ; 21a , b; 22a , b) additionally also a force component for engagement with the casting roll peripheral surface ( 6 ) receives. Arrangement according to one of claims 1 to 10, characterized in that a single flexible linear member ( 11 ) is provided, whose working area extends over the entire axial width of the casting roll peripheral surface ( 6 ). Arrangement according to one of claims 1 to 10, characterized in that two flexible linear members ( 21a , b; 22a , b) are arranged in opposite directions of movement, wherein the cleaning movement on the casting roll peripheral surface ( 6 ) takes place from the inside to the outside. Arrangement according to claim 12, characterized in that the working areas of the two flexible linear members ( 21a , b) in the axial direction of the casting roll peripheral surface ( 6 ) connect to each other or overlap partially. Arrangement according to claim 12, characterized in that the working areas of the two flexible linear members ( 22a , b) are separated from each other and each only over one of the two axial edge regions of the casting roll peripheral surface ( 6 ). Arrangement according to one of claims 1 to 14, characterized in that in the circumferential direction ( 4 ) of the casting roll peripheral surface ( 6 ) successively two flexible linear members ( 11 ) are arranged, of which the first operates in the dry state and the second in conjunction with a liquid detergent. Arrangement for film casting according to one of claims 1 to 15, characterized in that the components serving for the cleaning are combined into a separate assembly, which as a whole from the casting roll peripheral surface ( 6 ) can be lifted.

Images