EP1464240B1 - Method and apparatus for producing a fabric for the production of a filter rod - Google Patents

Description

The invention relates to a method and a device for producing a nonwoven fabric for the production of filter rods of the tobacco-processing industry, wherein the generic device comprises at least two separating devices, by means of the fibers of at least one sort filter material are singled, each separating device is a delivery shaft is provided.

A method for the preparation of filter materials and a corresponding device for the preparation of filter materials for the production of filters of the tobacco processing industry is known from GB 718 332. Here, by means of a tobacco cutter, snippets of a material are produced and fed to a stranding machine, similar to a cigarette rod making machine, whereby the chips are impregnated with a chemical agent to prevent an undesirable taste and to prevent the snippets from falling out of the end pieces of the correspondingly made filters. The cut chips are conveyed by means of a roller in the effective range of a spiked roller, and conveyed by means of the spiked roller from the roller on a conveyor belt to be subsequently fed to a further spiked roller, from which the chips are knocked out by means of another spiked roller and be supplied to a format in which the filter strand is formed with a wrapping strip. The snippets consist of materials such as paper, cellulose, textiles, synthetic materials or similar. and have a structure similar to cut tobacco.

Due to the shape of the chips, it is difficult to produce filters with homogeneous properties. In addition, the variability of the setting of the filter properties is only possible to a very limited extent.

A generic device and a generic method is known for example from DE 31 30 827 A1, which corresponds to GB 2,145,918 A known. In this document, a filler for cigarette filters is produced by passing a strip or stream of continuous fibers of the filler onto a spiked roller which is driven at a speed such that the fibers are torn by the spikes into pieces of irregular length and from the Roller be issued in arbitrary orientation. The torn fibers are shaken onto a conveyor belt and transferred to an uninterrupted carrier strip, which consists of the same or different filter materials. The carrier strip and filler are then formed into a filter strand. To form the filter strand this is fed to a strand forming machine, in which the carrier strip compressed laterally and formed into a continuous strand. It is thus made a filter strand in the longitudinal axial transport of the same. Subsequently, after production of the filter strand, the filter strand is cut to length in filter rods.

US 3 834 869 A discloses a method and a device for better distribution of fibers and particles in a liquid suspension, wherein first a corresponding distribution of the fibers or particles in a gas is provided, wherein the fibers or particles are then applied to a conveying element , Subsequent to the application to the conveyor element, the particles are transferred into a suspension and then aufauern in a container to a nonwoven.

US 3 050 427 A discloses an apparatus and a method for producing a nonwoven fabric in which the fibers are first singulated by means of a singulator and applied to a suction conveyor belt and subsequently crimped to produce a corresponding fiber mat. The fibers are provided before or after singulation with a corresponding additive which provides for bonding of the fibers.

US 3 792 943 A discloses an apparatus for producing a web of natural or synthetic fibers such as wood fibers, textile fibers, glass or mineral wool fibers, asbestos fibers and the like on an air-permeable belt with a drying process in which a flowing gas as a medium First of all, a fiber material is transported by means of a conveyor belt in a shower to a separating device in order to be conveyed by the separating device into an air stream which transports the separated fibers past a wall into a space. at the lower area of the fleece can shudder. The fleece forms on a suction belt.

US 2,931,076 A discloses an apparatus for producing a web of singulated fibers, wherein the fibers are first transferred to an air stream and then to a separating device and then applied to a conveyor belt.

In contrast, it is an object of the present invention to provide a method and an apparatus for producing a nonwoven fabric for the production of filter rods or filter strands of the tobacco processing industry, the quality is improved.

• Vereinzeln von Fasern wenigstens einer Sorte Filtermaterials in einer Vereinzelungsvorrichtung,
• Zuführen der vereinzelten Fasern zu einem Förderer, der sich in einer Förderrichtung bewegt, und
• Aufschauern der vereinzelten Fasern auf dem Förderer, wodurch sich ein Vlies bildet, wobei die Vereinzelungsvorrichtung wenigstens ein Vereinzelungselement umfasst, das um eine Rotationsachse rotiert.

The invention relates to a process for the production of a nonwoven for the production of filter rods of the tobacco processing industry with the following process steps:

• Separating fibers of at least one sort of filter material in a separating device,
• Feeding the singulated fibers to a conveyor moving in a conveying direction, and
• Churning of the separated fibers on the conveyor, whereby a nonwoven forms, wherein the separating device comprises at least one separating element which rotates about an axis of rotation.

By this method, it is possible to look up even fibers on the conveyor, so that the quality of the web formed or quilted on the conveyor increases and thus also the quality of the fiber strand formed from the nonwoven and the filter rods made from the fiber strand.

If the axis of rotation is aligned substantially parallel to the conveying direction of the conveyor, a particularly uniform shuddering of fibers is possible.

If fibers of at least two types are separated into separate separating devices, wherein in particular a sort of fibers is singled out for each separating device, the effectiveness of the singling and thus the degree of separation can be increased. It is expedient to bring the separated fibers together just before the conveyor, so that in the process management a pre-mixing of fibers can be omitted.

• Vereinzeln von Fasern wenigstens zweier Sorten Filtermaterials in voneinander getrennten Vereinzelungsvorrichtungen,
• Zuführen der vereinzelten Fasern zu einem Förderer, wobei die vereinzelten Fasern kurz vor dem Förderer zusammengeführt werden, und
• Aufschauern der zusammengeführten Fasern auf dem Förderer, wodurch sich das Vlies bildet.

The object is achieved by a method for producing a nonwoven fabric for the production of filter rods of the tobacco processing industry with the following method steps:

• Separating fibers of at least two types of filter material into separate separating devices,
• Feeding the singulated fibers to a conveyor, wherein the singulated fibers are brought together just before the conveyor, and
• Shuddering of the merged fibers on the conveyor to form the web.

By the method according to the invention, the quality of the forming nonwoven fabric can be increased, since the separation of the fibers in at least two sorts of filter material in separate separating devices, wherein in particular a sort filter material is singled out for each separating device, leads to an increased degree of separation, which subsequently leads to a more homogeneous fiber distribution in the quilted web. Thus, both the quality of the nonwoven fabric is increased, as well as the resulting filter strand and the filter rods cut to length from this later.

If the separating devices each comprise at least one separating element which rotate about axes of rotation which are aligned essentially parallel to the conveying direction of the conveyor, a more uniform distribution of the fibers on the conveyor can be achieved. In a preferred embodiment of the method according to the invention, the churning of the fibers or of the filter material takes place from the top onto the conveyor. As a result, a compact process control is possible.

If one type of fiber is a multiple-component fiber, especially bicomponent fiber, very efficient filter strands or filter rods can be produced. With respect to these materials, full reference is made to Applicant's European Patent Application No. 03 004 594.2 entitled "Cigarette Filter and Method of Making the same". The multiple-component fibers or bicomponent fibers make it possible in a simple manner to connect the fibers in the filter strand or filter rod. For this purpose, the multicomponent fibers, in particular bicomponent fibers, comprise a core and a shell of different material, wherein the filler material has a lower melting point than the core material. In this case, a very secure composite of the fibers can be produced in the filter, for which purpose the filter or the mixture of fibers, which is available as a filter material or from which the filter or the filter rod is made, is brought to a temperature which is slightly above the melting point of the shell material. In this way, a bonding of filter components is possible.

In a corresponding bicomponent fiber, the sheath may be polyethylene (PE) and the core may be polyester or polyethylene terephthalate (PET), for example. The melting point of the shell is then at 127 ° C and the melting point of the core at 256 ° C. This gives a very dimensionally stable bicomponent fiber whose shell material has a lower melting point than the core material. A Trevira bicomponent fiber, for example and preferably used, is of type 255, has a denier of 3.0 dtex, a cut length of between 3 and 6 mm, a core of PES (synthetic fiber of polyester), and a sheath of copolyethylene , wherein the shell or the shell is modified to increase adhesion, that is provided with additives that lead to a lower surface tension.

After supplying energy, the filter materials can then adhere or stick over at least at points of contact with the multicomponent fibers or bicomponent fibers. At a temperature which is above the melting temperature of the shell, the shell softens or melts accordingly, so that an adhesive bond or adhesive bond to other components of the filter can arise at points of contact. After cooling the corresponding filter components, a very dimensionally stable filter is produced.

If at least one type of granules and / or powder is fed shortly before the conveyor, a filter rod with improved filter quality be generated. In the context of this invention, the term granules also includes the term extrudate. The preferred filter material or a preferred composition of filter material comprises 80% by weight to 95% by weight of activated carbon granulate and 5% by weight to 20% by weight of fibers, in particular bicomponent fibers. It is also possible to produce filters which consist of various fibers, for example bicomponent fibers, cellulose fibers and activated carbon fibers, the component or fraction of bicomponent fibers being between 5 and 20% by weight (% by weight) and the proportion of cellulose fibers between 20 and 95% by weight % lies. The remainder may then consist, for example, of activated carbon fibers.

The transport and / or the separation of the fibers is preferably done with transport air, which can then be discharged substantially in the region of the conveyor by negative pressure.

There is further provided a device for producing a nonwoven fabric for the production of filter rods of the tobacco processing industry with at least one separating device, by means of which fibers of at least one sort of filter material are separable, and a conveyor on which the separated fibers are aufschauerbar to form a nonwoven fabric, indicated, wherein the at least one separating device comprises at least one rotating separating element. Due to the rotating separating element, a particularly high degree of singulation of fibers can be achieved, as a result of which the density of the nonwoven fabric produced becomes very uniform.

If the axis of rotation of the separating element is aligned substantially parallel to the conveying direction of the conveyor, an even more uniform density of the nonwoven can be achieved. Due to the special orientation of the singling drum, it is possible to deliver very evenly separated fibers to the conveyor. For this reason, the quality of the produced nonwoven and subsequently the quality of the filter rods produced therefrom increase.

If at least two separating devices are provided which are separate from one another, the degree of separation of the fibers can be increased. The separating devices are then arranged next to each other in the conveying direction and not in a row. The separation devices are designed to separate one type of fiber at a time. For this purpose, for example, singulating drums contained in the singulating devices have differently configured sieves which can be adapted to the respective fibers, for example the diameter and / or the length. If a delivery well is arranged downstream of the separation devices downstream of the conveying direction of the fibers, the separated fibers can be safely supplied to the conveyor.

An effective mixing of the fibers or other filter material components happens when the conveyor wells are brought together just before the conveyor in a chamber. Preferably, further filter components such as granules, powders and / or extrudates are also each fed to a delivery shaft or delivery wells which are brought together in the chamber with the further delivery wells.

The object is further achieved by a device for producing a nonwoven fabric for the production of filter rods of the tobacco processing industry with at least two separating devices by means of the fibers of a variety filter material are singled, each separation device is provided a delivery shaft and wherein the separating devices separated from each other are configured, wherein the delivery chutes are merged downstream in the end in a chamber, wherein a conveyor is provided, which is arranged downstream of the separating devices and adjacent to the chamber and is designed to aufzauer individual fibers to form a nonwoven fabric. As a result, the degree of separation of the fibers is increased, so that the quality of the fiber fleece and thus the subsequently produced filter rods is increased. Also for this purpose singling drums are preferably provided, for example, have different trained screens.

The provision of separate separating devices means in particular that they are arranged side by side in the conveying direction and not in succession. Fibers on one side arrive exclusively in one of the separated separating devices and not in another one of the separate separating devices.

If the separating devices each comprise at least one separating element whose axis of rotation is oriented essentially parallel to the conveying direction of the conveyor, a very uniform shuddering of the fibers in a fiber fleece on the conveyor can take place. In addition, effective mixing is possible. Also in this embodiment according to the invention granules, powders, extrudates or other filter materials can be supplied through delivery chutes of the chamber.

If the at least two separating devices are arranged above the conveyor, a very effective and space-saving device can be realized. Here, the filter material is thrown on top of the conveyor directly from above.

• Transportieren endlicher, im wesentlichen vollständig vereinzelter Fasern wenigstens einer Sorte mit Transportluft in - Richtung eines Förderers,
• Bilden eines Faservlieses von sich wenigstens teilweise berührenden Fasern auf einer Oberfläche des Förderers
• Aufbringen des Faservlieses auf einen Umhüllungsstreifen und
• Umhüllen des Faservlieses mit dem Umhüllungsstreifen.

A preferred filter strand manufacturing process comprises the following process steps:

• Transporting finite, substantially completely separated fibers of at least one sort with transport air in the direction of a conveyor,
• Forming a fibrous web of at least partially contacting fibers on a surface of the conveyor
• Applying the fibrous web to a wrapping strip and
• Wrapping the fibrous web with the wrapping strip.

It was in fact recognized that, in particular with transport air transported in the direction of a conveyor, substantially completely separated fibers, wherein forms a nonwoven fabric on a surface of the conveyor, leading to a production of a filter strand with very homogeneous filter properties. The conveyor is in the context of this invention, in particular a belt conveyor and in particular preferably a suction belt.

When wrapping the fibrous web with the wrapping material strip, the fibrous web is expediently shaped, so that a compact filter strand is formed. When energy is applied thereto during or after the wrapping of the fibrous web with the wrapping material strip to produce a strong bond at the points of contact of the fibers, it is possible to make the filter relatively elastic and to ensure that at the cut edges of the filter or ribbons Filter element no fiber material fall out.

In the variant in which the fibers have a length which is shorter than a filter or filter element separated from the fiber strand produced, particularly homogeneous filter properties are possible. Preference is given to fibers of at least one fiber type, with an average fiber diameter in the range from 10 to 40 μm, in particular from 20 to 38 μm. The fibers which are preferably to be used are thus elongated and relatively thin. If additives such as activated carbon granules, triacetin or latex are preferably added to the fibers, the filter properties are particularly easy to adjust. Activated carbon granules are added, for example, prior to complete singulation of the fibers or to the fibers being transported to the conveyor. Triacetin or latex as a binder are added, for example, to the quenched fiber fleece in the region of the conveyor.

If the nonwoven fabric is compacted prior to the step of applying to the wrapping strip, a particularly uniform compaction can be ensured. For this purpose, the compression preferably takes place both vertically and horizontally, that is, for example, from above and below as well as from the sides of the fiber fleece.

A particularly simple procedure is given when the nonwoven fabric for applying to the wrapping strip mechanically, in particular by means of compressed air, is detached from the conveyor.

Preferably, the fibrous web is formed prior to application to the wrapping strip. In this case, for example, the forming step may provide at least the formation of a semicircle transversely to the conveying direction of the nonwoven. Preferably, a full circle or Oval formed.

Conveniently, a filter or filter element is made by the aforesaid filter strand manufacturing process by subsequent cutting to length from the produced filter strand.

It is also a filter strand manufacturing apparatus comprising a chiller device by which singulated filter materials are transported onto a conveyor to form a nonwoven fabric, a format apparatus in which a wrapping material is wrapped around the nonwoven fabric, and means for transferring the nonwoven fabric from the conveyor to the conveyor Forming device expedient that the Aufschauervorrichtung by means of transport air allows transport of the filter materials to the conveyor.

By transporting the separated filter materials by means of transport air, a particularly homogeneous nonwoven fabric can be produced, so that a particularly homogeneous filter strand and therefore particularly homogeneous filter or filter elements can be produced.

If at least one compacting device is provided in the region of the conveyor, the filter properties are to be positively influenced. For this purpose, the conveyor or a part of the conveyor is preferably part of the compacting device. A particularly easy to implement filter strand manufacturing device is given when the conveyor comprises at least one suction belt. If the fibers to be processed are so small that the openings of the suction belt clog quickly, it is advantageous to work with two additional suction belts, which are each arranged at approximately right angles on both sides of the first suction belt. A particularly effective transfer of the nonwoven fabric is done by means of compressed air, by which the nonwoven fabric from the conveyor detachable is.

If the device for transferring the nonwoven fabric comprises a conveyor belt, it is possible that the nonwoven fabric according to the properties of the filter to be produced or with respect to the shape of the filter to be produced accordingly. Preferably, the conveyor belt is a suction belt. A particularly preferred embodiment is given when the conveyor belt is bent transversely to the transport direction. In this way, for example, a filter strand which is round or oval in cross-section can be produced in a simple manner. For this purpose, preferably two conveyor belts are provided, which transport the fiber fleece between them. The conveyor belts are designed such that the nonwoven fabric is round or oval malleable. For this purpose, the conveyor belts, for example, each form a semicircle or a half oval.

An alternative transfer device is provided when the device for transferring the nonwoven fabric comprises a nozzle through which the nonwoven fabric is transportable. Preferably, the nozzle is designed such that the nonwoven fabric is round or oval malleable.

Fig. 1

eine dreidimensionale schematische Darstellung einer Vereinzelungsvorrichtung sowie eines Teils einer Aufschauervorrichtung,

Fig. 2

eine schematische Ansicht einer Vorrichtung zur Filterstrangherstellung,

Fig. 3

einen Teil der Fig. 2 in einer Draufsicht in Richtung des Pfeils A,

Fig. 4

einen Teil der Fig. 2 in schematischer Darstellung in Seitenansicht, in Richtung des Pfeils B,

Fig. 5

eine schematische Ansicht einer weiteren Vorrichtung zur Filterstrangherstellung,

Fig. 6

einen Teil der Fig. 5 in einer Draufsicht in Richtung des Pfeils A,

Fig. 7

einen Teil der Fig. 5 in schematischer Darstellung in Seitenansicht, in Richtung des Pfeils B,

Fig. 8

eine schematische Ansicht eines Teils einer Vorrichtung zur Filterstrangherstellung, bei der Teile zur Vereinfachung weggelassen wurden,

Fig. 9

eine Draufsicht auf die Vorrichtung gemäß Fig. 8 in schematischer Darstellung, ohne Vereinzelungsvorrichtung,

Fig. 10

einen Teil einer Ausführungsform einer Filterstrangherstellvorrichtung in schematischer dreidimensionaler Darstellung,

Fig. 11

eine schematische Ansicht eines Teils einer Filterstrangherstellungsvorrichtung,

Fig. 12

eine weitere Ausführungsform eines Teils einer Filterstrangherstellungsvorrichtung in einer weiteren schematischen Ansicht,

Fig. 13

eine schematische dreidimensionale Darstellung einer erfindungsgemäßen Vorrichtung zur Herstellung eines Vlieses, und

Fig. 14

eine schematische Schnittdarstellung eines Teils einer weiteren erfindungsgemäßen Vorrichtung zur Herstellung eines Vlieses.

The invention will now be described with reference to the drawings, to which reference is otherwise expressly made with respect to all details of the invention not explained in detail in the text. Show it:

Fig. 1

a three-dimensional schematic representation of a separating device and a part of a Aufschauervorrichtung,

Fig. 2

a schematic view of an apparatus for Producing filter rod,

Fig. 3

2 a part of a plan view in the direction of the arrow A,

Fig. 4

2 shows a schematic representation in side view, in the direction of arrow B,

Fig. 5

a schematic view of another device for filter rod manufacturing,

Fig. 6

5 is a plan view in the direction of the arrow A,

Fig. 7

5 shows a schematic representation in side view, in the direction of the arrow B, FIG.

Fig. 8

FIG. 2 is a schematic view of a part of a filter rod manufacturing apparatus with parts omitted for simplicity; FIG.

Fig. 9

8 shows a plan view of the device according to FIG. 8 in a schematic illustration, without a separating device, FIG.

Fig. 10

a part of an embodiment of a filter strand manufacturing device in a schematic three-dimensional representation,

Fig. 11

a schematic view of a part of a filter rod manufacturing device,

Fig. 12

a further embodiment of a part of a filter rod manufacturing device in a further schematic view,

Fig. 13

a schematic three-dimensional representation of a device according to the invention for producing a nonwoven, and

Fig. 14

a schematic sectional view of part of another device according to the invention for producing a nonwoven fabric.

FIG. 1 shows a separating device 10 in a schematic three-dimensional representation. This is a variant of a separating device 10 which is disclosed in a further European patent application of the applicant entitled "Process for the preparation of finite fibers and fining fiber preparation device for use in the production of filters", No. 03 007 672.3 is. The subject of this patent application is that of preparing fibrous material intended for use in the manufacture of filters, in order to obtain substantially completely separated fibers and thus a homogeneous filter strand to be produced from these fibers. This is u.a. the separating device 10 of FIG. 1. Ggf. the filter material or fiber material is already vorvereinzelt in advance and dosed accordingly.

The substantially unaccompanied fiber material or fiber / fiber group mixture 49 is, for example, as in FIG. 4 schematically is shown, via a stowage 44 and feed rollers 46 in the effective range of a spiked roller 76 moves, which ausschlägt the fiber / fiber group mixture vorvereinzelt. This fiber / fiber group mixture 49 is then gem by the air streams 19 in the screening drums 21. Fig. 1 transported. This takes place via lateral openings 20 in the housing 22. The fiber material is blown in the direction of the longitudinal axes of the screening drums 21. The two-sided blowing of the fiber material counterclockwise results in a circumferential annular flow 23. The annular flow 23 is superimposed by a flow normal or substantially perpendicular to this, which is caused by a vacuum applied to the fluidized bed 14 and an air flow 13. Airflow 13 is an option for larger, heavier fibers, which is not always necessary. The negative pressure prevailing at the fluidized bed end 14 is created by the negative pressure in a suction belt conveyor, not shown, which is arranged at the fluidized bed end 14 and the other by the air flow 17, which is conveyed through the suction nozzle 16. The normal flow begins above the Siebtrommein 21 their beginning and happens and flows through the Siebtrommeln 21 through the shell openings. The normal flow then passes into the fluidized bed region 11 and passes through it to the end of the 14th

The ununsulated or substantially unaccompanied fiber material passes in the drums 21 on the inner circumferential surfaces of the drums 21. The drums 21 rotate in a direction of rotation 24 of the screening drums 21 in a clockwise direction. The essentially unaccurate fiber material mounted on the drum shell surfaces is fed to the separating rollers 26 by the rotating drums. The separating rollers 26 rotate in the direction of rotation 25 counterclockwise. It would also be possible as an alternative, a clockwise rotation. It can all the others find flexible rotary variants use. The separating rollers 26, which may be formed as needle rollers, detect the unclassified fiber groups and tear and accelerate them. The fiber groups are thrown so long against the inner surface of the drums 21 until they have dissolved in individual fibers and have passed the shell openings or can pass through the shell openings. Instead of a sieve drum 21, a drum with perforated plates or Rundstabgitter can be provided.

The fibers or individual fibers are detected by an air flow and guided or sucked through the radial openings of the drum. The air flow conveys the fibers down to the fluidized bed. Once the fiber-laden flow has reached the fluidized bed, it is deflected and guided along the curved fluidized bed. Due to the centrifugal forces acting on the fibers, the fibers move to the curved guide wall and flow to the suction belt conveyor. The air flowing in above the fibers is deposited on the wedge or separator 15 and discharged via the suction nozzle 16.

In Fig. 1, the corresponding fiber streams 18 are shown schematically. Optionally, isolated fibers are detected by an air stream 13 emerging from the nozzle column 12 and are also supplied to the fluid bed end 14 accordingly. It can also be provided more nozzle strips.
Fiber groups that were not or not completely separated by a single drum passage through the drums 21, go with the ring flow 23 in the respective parallel drum 21. The singulation device shown in Fig. 1 corresponds at least partially to that described in WO 01/54873 A1 or US Pat. No. 4,640,810 A from Scanweb, Denmark, or USA are.

The singling is done essentially by interaction of the drums 21 with the rollers and an air flow and in particular by the fact that only isolated fibers have the opportunity to pass through the openings of the drum 21. The fiber streams 18, which are given by transport air, lead the separated fibers in the direction of the fluidized bed end 14, wherein the distance to the fluidized bed 11 due to the centrifugal force is getting smaller. In order to separate air from the fibers, the flow divider 15 is provided.

FIG. 2 shows a schematic view of a strand production machine 9.

FIG. 3 shows a part of the strand production machine 9 according to the invention from FIG. 2 in a plan view in the direction of the arrow A of FIG. 2 and FIG. 4 shows a side view of the strand production machine 9 according to the invention. Fig. 2 in the direction of arrow B.

The unaccurate fiber material 49 passes via the stowage shaft 44 to the metering device 46 or 76, comprising two feed rollers 46, a metering channel which is arranged between the feed rollers 46 and the spiked roller 76 and a spiked roller 76. The direction of the material entry 47 is shown in FIG in drawing plane down, as shown schematically there. The unclarified fiber material 49 is separated in the separation chamber 10. The separation is done by an interaction of the separating rollers 26 with an air flow 50 and openings in a grid 77, which separates the separation chamber 10 from the space associated with the fluidized bed 11. The air flow generated by the air flow in the exhaust pipe 16 on the fluidized bed 11 promotes the separated fibers 27. The air flow 17 in the exhaust pipe 16 is with respect to its direction in Fig. 3 up out of the plane, as shown in Fig. 3. The air flow 17 also transports excess fibers. The air flow 28 serves to hold and compress the fibers 27 which have been quenched on the suction belt 43 of the suction belt conveyor 32.

The separated fibers 27 move on the Fileßbett 11 toward the fluid bed end 14, on which a Saugbandförderer 32 is arranged. In Saugbandförderer 28 prevails by continuous air suction vacuum. This air suction is shown schematically by the air flow 28. The negative pressure sucks the separated fibers 27 and holds them on the air-permeable suction belt of the suction belt conveyor 32.

The suction belt 43 moves in the direction of strand production machine 9, that is, in Fig. 2 to the left. A fiber cake 29 or fiber stream 29, which increases almost linearly in the direction of the stranding machine 9, is formed on the suction belt. The heaped-up fiber stream 29 has different strengths and is trimmed at the end of the filling zone of the suction belt conveyor by trimming by a trimming device 31 to a uniform thickness. The trimming device 31 may be a mechanical one such as, for example, trimmer discs or a pneumatic, by means of air nozzles, for example. The mechanical trim is known per se in cigarette rod making machines. The pneumatic trimming is done in such a way that at the end of the fiber stream 29 a nozzle is arranged horizontally, from which an air jet emerges and tears a part of the fiber stream 29, so that excess fibers 30 are removed. It can a point jet nozzle or a flat jet nozzle find use.

After trimming, the fiber stream 29 is split into a trimmed fiber strand 33 and a strand of excess fibers 30. It is also possible to grasp and tear away all fibers below a trim level from a jet. The excess fibers are returned to the fiber preparation process and later re-formed into a fiber strand.

The trimmed fiber strand 33 is held on the suction belt 43 and moved in the direction of the stranding machine 9. The trimmed fiber strand 33 is a loose nonwoven fabric which is compressed by a compacting belt 35. Instead of the compacting belt 35, a roller, such as, for example, a press disk 55 (see, for example, FIG. It can also be used several bands or rolls or discs use. There is also a lateral compression of the fiber cake, as shown in particular by Fig. 3. In Fig. 3, the compression belts 48 are shown, which are conical to each other and in Saugbandgeschwindigkeit with the fiber cake. The toothed shape of the compression bands 48 create zones of different density in the compacted fiber cake. In the higher density zones, the filter strand is cut later. The higher fiber density in the filter end area ensures a more compact cohesion of the fibers in this sensitive zone and also improves the processability of the filter rods. For compacting in the vertical direction, a compression belt 35 is provided in FIG.

The trimmed and compacted fiber strand 34 is transferred to the stranding machine 9. The transfer takes place by detaching the compacted fiber strand 34 from the suction belt 43 and placing the Fiber strand 34 on a format strip or on a wrapping material strip, which is applied to a format strip of the stranding machine 9. The format tape is not shown in the figures. This can be a conventional format strip which is also used in a normal filter rod machine or cigarette rod machine. The transfer is supported by a nozzle 36 directed from above onto the compacted fiber strand 34 and through which an air flow 37 flows. In the stranding machine 9, a fiber filter strand 38 is formed, wherein from a bobbin 41, a wrapping material strip 42 is withdrawn and wound around the fiber material as usual. By volume reduction and circular shaping or oval shaping of the compacted fiber strand 34 when wrapping with the wrapping material strip 42 or, as will be shown below, before wrapping with the wrapping material strip, a certain internal pressure builds up in the fiber filter strand 38.

In the curing device 39, binding components contained in the fiber mixture are superficially heated and fused. Similarly, the outer layers of bicomponent fibers that may be included in the fiber blend may also be fused to form a bond between the fibers. Reference is made in particular to the patent application of the applicant DE 102 17 410.5. As fiber materials, a variety of fibers can be used, which are suitable for the desired filter properties. For example, cellulose acetate, cellulose, carbon fibers and multicomponent fibers, in particular bicomponent fibers, are suitable as fiber materials. With regard to the components in question, reference is made in particular to DE 102 17 410.5 of the Applicant.

The different types of fiber are preferably mixed prior to strand formation. It is also possible to add at least one additive. The additive is, for example, a binder such as latex or triacetin or granular material which binds components of the cigarette smoke particularly effectively, such as, for example, activated carbon granules.

It is particularly preferred if the fiber length of the fibers used is smaller than the length of the filter or filter element to be produced. The length of the fibers should therefore be between 0.1 mm and 30 mm and in particular between 0.2 mm and 10 mm. The length of the filter to be produced is a conventional filter for a cigarette or a filter segment in multi-segment filters of cigarettes. In addition, if the average fiber diameter in the range of 10 to 40 .mu.m, in particular 20 to 38 microns and more preferably between 30 and 35 microns, a very homogeneous filter can be produced.

The curing device 39 may include a microwave heater, a laser heater, heating plates or sliding contacts. By heating the binding components, for example, the outer layer of bicomponent fibers or latex, the individual fibers combine in the fiber strand and merge superficially. The curing device 39 may also allow for drying of binding components added in liquid form. Upon cooling of the fiber strand, the melted areas of the heated binding components harden again. The resulting lattice framework gives the fiber strand stability and hardness.

Finally, the cured fiber filter strand 38 is cut into filter rods 40. The curing of the filter is also after the Cutting into the filter rods 40 possible.

Fig. 5 shows a strand manufacturing machine 9 in a schematic representation. 6 shows a part of the strand-making machine 9 in a plan view in the direction of the arrow A of FIG. 5, and FIG. 7 shows a side view of the strand-making machine 9 according to FIG. 5 in the direction of the arrow B.

In contrast to the strand production machine 9 gem. 2 to 4, the singulated fiber material 27 is thrown onto the suction belt 43 from above in this exemplary embodiment, specifically in the transport direction 74. The separating device 10, which is also shown schematically in FIGS. 5 to 7, represents a modified form of the separating device 10 In the separating chamber 45 are screening drums 21 which rotate in the direction of the arrow. There are also separating rollers 26 in the form of spiked rollers; However, these are arranged in a modification of FIG. 1, relatively centrally in the screening drums 21. The spiked rollers 26 are also used in this case to strike the not yet isolated fiber material or the contiguous fiber groups apart in individual fibers, so that the separated fibers can pass through the outlet openings of the screen drum 21 in the hopper 53. By the corresponding air streams and in this case also the gravity, then the isolated fibers 27 reach into the region of the suction belt conveyor 32, which is configured in this case with Saugbandwangen 57.

A homogeneous Aufschauerung of the fibers 27 happens in particular by the fact that the screen drum 21 comprises a separating roller 26, wherein the screening drum and the separating roller have longitudinal axes, in particular the separating roller 26 has a rotation axis 91 which is parallel or substantially parallel is aligned with the conveying direction 92 of the suction belt conveyor 43. As a result of this special orientation of the screening drum 21 and the separating roller 26, the fiber fleece 29 or the fiber stream 29 can be thrown on the conveyor 43 very uniformly.

A corresponding fiber stream 29 is thrown on the suction belt 43. Excess fiber material 30 is removed by a trimmer 31 from the remaining fiber strand 33 above it. The trimmed fiber strand 33 is compressed by means of a pressing disk 55 which is at the same time the rearward strand of the suction belt 43 'in the conveying direction of the strand. Shortly behind the press disk 55, the compacted fiber strand 34 is held by a suction belt 43 'from above. For this purpose, a negative pressure field 54 is generated by means of an air flow 28. In order to enable a detachment of the suction belt 43 ', an air flow 37 is provided, which hits through the nozzle 36 on the suction belt. The compacted fiber strand 34 is then removed from the suction belt 43 'by means of an air flow 37 through the nozzle 36 and transferred to a format 56. For this purpose, the compacted fiber strand 34 as usual reaches a wrapping material strip 42, which is conveyed on a format strip. The remaining process steps correspond to those according to FIGS. 2 to 4.

FIG. 8 shows a part of a further device in a schematic view. The suction belt 43 is deflected around deflection rollers 59. The fiber stream 29, which is gradually built up, becomes the trimmed fiber strand 33 after trimming. The trimming device is not shown in this illustration of FIG. In the region of the churning of the fiber strand 29, individual fibers 27 reach the fiber strand from below.

Subsequently, the fiber strand 33 reaches a wrapping material strip 42, which comes on a format tape 58. The format band 58 and the wrapping material strip 42 are deflected by corresponding rollers 59. In the area of the roller 61, the fiber strand 44 reaches the wrapping material strip 42. At this point, the beginning of the format 56 is wound in the usual manner of the wrapping material strip 42 around the fiber strand 33.

In Fig. 9 is a plan view of the device of Fig. 8 is shown, in particular a particularity of the side cheeks 57 is disclosed. The side cheeks 57, which in fact also adjoin the fiber strand 29 or 33, are configured as suction belts 43, which in turn are deflected around deflection rollers 59 again. For particularly small and thin fibers, it may be necessary to provide not only a suction belt, but, as in this embodiment, three suction belts, so that the fiber material is held in accordance with the suction strand or the Saugsträngen.

Fig. 10 shows a schematic three-dimensional representation of a device for transferring the fiber strand from the suction belt 43 on the format 56 and in particular on the wrapping material strip 42. The fiber strand, which is not shown in this figure, comes from the lower portion of the suction belt 43, the is deflected over the guide roller 59, in the free space of the opposing belts 62nd

The belts 62, which may in particular also be steel belts, are deflected by rollers 63. The configuration of the bands 62 results in a corresponding round cavity between two opposite bands 62. The fiber strand 34 passes through this hollow space with a round cross section and is placed on the wrapping material strip 42. Through the transfer device Preforming of the fiber strand 34 and possibly further compression is made possible. In this embodiment, the Saugbandwangen 57 are designed as a solid side walls.

11 shows a section of a strand production device 9 in a schematic representation. The fibrous stream 29 of singulated fibers 27, which has been thrown up from above in a funnel 53, reaches the suction belt 43 and the operative area of a pressure belt 64, which is deflected around rollers 65. The correspondingly compacted fiber strand passes into a nozzle 66 and is further conveyed by means of an air stream 67 onto a wrapping material strip 42 which rests on a format belt 58. Subsequently, the fiber strand is wrapped as usual with the wrapping material strip 42 to form a fiber filter strand 38.

FIG. 12 shows a section of a further strand production device 9 in a schematic representation. The fiber strand 33 conveyed by the suction belt 43 passes into the effective region of a nozzle 68, which applies compressed air 69 to the fiber strand in the region of the deflection roller 65 and thereby removes the fiber strand 33 from the suction belt 43. The angle of the nozzle or the compressed air acting on the fiber strand 33 is adjustable. After detachment of the fiber strand 33 from the suction belt 43, this passes into the annular nozzle 70. The air 67 flowing through the nozzle slot 71 can fulfill various functions, depending on the nozzle design. The function is always such that the vacuum prevailing in the nozzle inlet channel of the nozzle 70 dissolves the fiber strand 33 from the suction belt 43 running on the deflection roller 65, which may also be designed as a pressure disk 65. In addition, by impinging the compressed air 67 onto the fiber strand at certain angles, the fiber strand can allow the fiber strand to be conveyed into the first format-forming hollow cone 72. As a variant, it is possible that the Compressed air 67 dissolves the strand into individual fibers or fiber groups and thus promotes the individual fibers or fiber groups in the first formatblldenden hollow cone 72. By the compressed air of the fiber strand or the individual fibers and fiber groups in the first formatblldenden hollow cone 72 and then in the second format-forming hollow cone 73 are promoted. Under the second format-forming hollow cone 73, the format strip 58 runs with the wrapping material strip 42 lying thereon. The second hollow cone 73 has a smaller taper than the first hollow cone 72. In the first format-forming hollow cone 72 are ventilation holes. These vent holes provide for the air separation of the nozzle air 69 and 67th

In the first case in which the fiber strand 33 is transferred as a fiber strand, this is formed in the format-forming hollow cones 72 and 73 from above and from the format in progress format tape 58 from below. The complete transfer of the fiber strand 33 onto the format strip or wrapping material strip 42 takes place under the hollow cone 73. In the second variant, in which individual fibers and fiber groups are pressed by the nozzle air 69 into the format-forming hollow cone, the tapering of the hollow cone occurs a congestion of the individual fibers and fiber groups, so that forms a new fiber strand. The strand is formed completely in the second hollow cone 73 and transferred at the end of the second hollow cone 73 to the format strip or the wrapping material strip 42. Subsequently, the wrapping material strip 42 is wound around the strand as usual and sealed so as to form the fiber filter strand 38.

In contrast to the production of cigarette rods, the difficulty of the filter strand production acc. the invention therein, filter materials of fine fibers with or without corresponding Additives such as coal activated granules or powder To form into homogeneous filter strands. Accordingly, the various elements or devices are designed to optimally transport, hold or process the materials used.

The fibrous materials may be cellulosic fibers, thermoplastic starch fibers, flax fibers, hemp fibers, flax fibers, sheep wool fibers, cotton fibers or multicomponent fibers, in particular bicomponent fibers having a length smaller than the filter to be produced and having a thickness, for example. in the range of 25 and 30 microns. Thus, for example, cellulose fibers of the stora fluff EF type untreated from Stora Enso Pulp AB can be used which have an average cross section of 30 μm and a length of between 0.4 and 7.2 mm. As synthetic fibers such as, for example, bicomponent fibers, fibers of the type Trevira 255 3.0 dtex HM with a length of 6 mm from Trevira GmbH can be used. These have a diameter of 25 microns. As other synthetic fibers, cellulose acetate fibers, polypropylene fibers, polyethylene fibers and polyethylene terephthalate fibers can be used. The additives can be found in the flavor or smoke-influencing materials, such as activated charcoal granules or flavoring agents, and also binders by means of which the fibers can be glued together.

13 shows a schematic three-dimensional view of a device according to the invention for producing a nonwoven for the production of filter rods of the tobacco-processing industry. There are five separating devices 80 are provided, the singulating drums 81 have, for example in the form of screening drums, which have been described in detail above. Within the singulating drums 81, which in Fig. 13 only by means of a Example, separating rollers 26 may be arranged, as also described above. Reference is made in this regard in particular to FIGS. 5 to 7 as well as FIG. 1. The singling drum 81 may be designed to rotate about a rotation axis 91. However, the singling drum 81 can also be fixed, in which case a longitudinal axis is provided which coincides with the rotation axis 91 shown in FIG. A separating roller may also be arranged in the Verelnzelungstrommel 81 which rotates about a rotation axis 91 and a rotation axis 91 parallel to the axis of rotation shifted. The singulating drums 81 and screening drums are designed to effectively separate fibers of one variety. For this purpose, the screens of the screening drum can be adapted to the length and the diameter of the fibers to be separated, for example with regard to their length and width.

Downstream of the Faserförderrlchtung close to the separating devices 80 delivery chutes 82, which feed the singulated fiber material a union element 83, which has a chamber 87 in the lower region into which the delivery wells 82 open. Following the chamber 87 or in the lower region of the union element 83, a suction belt conveyor 84 is arranged.

In the chamber 87, the filter materials are mixed accordingly. These are conveyed both via gravity but essentially via transport air, so that due to the turbulence of the transport air in the chamber 87 a good mixing is achieved. After the transfer region 85, the mixed and separated fibers, which may optionally be mixed by granules, which are supplied for example by a further shaft, not shown, of the chamber 87, in the Effective range of the suction belt 86 of Saugbandförderers 84 transferred. Here then a fiber fleece 88 is woken up.

The nonwoven fabric 88 is shown in FIG. 14. The suction belt 86 moves in the conveying direction 92, so that the aufschauernde nonwoven fabric increases in thickness in the conveying direction.

FIG. 14 shows a detail of FIG. 13, in which the area of the mixing chamber 87 is shown in somewhat greater detail, in a schematic section of such a device. The delivery wells 82 are initially aligned in parallel at the top, which is a change compared to the embodiment of FIG. The fibers 90 and granules 89 are also shown. In this exemplary embodiment of FIG. 14, three different types of fiber and two different types of granules are fed to the chamber 87 and then thrown to form a fiber web 88 on the conveyor belt 86. The conveying air is sucked off below the suction belt 86 by a negative pressure prevailing there.

After churning of the web 88 of the nonwoven fabric is fed to a strand forming device, as described above. It can then take place heating of the nonwoven, so that, for example, used bicomponent melts as a constituent of the filter material or the fleece to the shell, so that after curing of the same a solid and air-permeable composite. For each separating device 80, only one type of fiber is preferably supplied. Dosing also takes place during the supply of these fibers to the separating device 80 in each case.

LIST OF REFERENCE NUMBERS

9

Strand manufacturing apparatus

10

separating device

11

fluidized bed

12

nozzle bar

13

airflow

14

Fluidized bed end

15

flow divider

16

suction

17

airflow

18

fiber stream

19

airflow

20

opening

21

screen drum

22

casing

23

annular flow

24

Rotation direction of the sieve drum

25

Rotation direction of the separating roller

26

Verelnzelungswalze

27

isolated fibers

28

airflow

29

fiber stream

30

excess fibers

31

trimming device

32

suction belt

33

trimmed fiber strand

34

compacted fiber strand

35

compression band

36

jet

37

airflow

38

filter rod

39

curing

40

filter rod

41

reel

42

Wrapping material strip

43

suction belt

44

accumulating shaft

45

separation chamber

46

feed roller

47

material input

48

compression band

49

Fiber / fiber group mixture

50

airflow

52

suction

53

funnel

54

Under pressure field

55

dummy block

56

format

57

Saugbandwange

58

format tape

59

idler pulley

61

role

62

tape

64

pressure belt

63

role

65

role

66

jet

67

airflow

68

jet

69

compressed air

70

ring nozzle

71

nozzle slot

72

1. hollow cone

73

2. hollow cone

74

Transport direction of the filter material

75

transport direction

76

spiked roller

77

grid

80

separating device

81

separator drum

82

production well

83

combining element

84

Saugförderer

85

Transfer area

86

suction belt

87

chamber

88

non-woven fabric

89

granules

90

fibers

91

rotational axes

92

conveying direction

Claims (8)

1. Method for producing a fibrous web (29, 33, 34, 88) for the production of filter sticks (40) of the tobacco processing industry, comprising the following method steps:

   - separating fibres (27, 90) of at least two types of filter material in separating devices (10, 80) which are separate from one another,

   - supplying the separated fibres (27, 90) to a conveyor (32, 43, 84, 86), wherein the separated fibres (27, 90) are merged just before the conveyor (32, 43, 84, 86), and

   - showering the merged fibres (27, 90) onto the conveyor (32, 43, 84, 86), as a result of which the fibrous web (29, 33, 34, 38, 88) is formed.
2. Method according to Claim 1, characterised in that the separating devices (10, 80) in each case comprise at least one separating element (21, 26, 76, 81), which elements rotate about axes of rotation (91) which are oriented substantially parallel to the conveying direction (92) of the conveyor (34, 43, 84, 86).
3. Method according to Claim 1 or 2, characterised in that the fibres are showered onto the conveyor (32, 43, 84, 86) from above.
4. Method according to any one of Claims 1 to 3, characterised in that one type of fibre (27, 90) is a multiple component fibre, in particular a bicomponent fibre.
5. Method according to any one of Claims 1 to 4, characterised in that at least one type of granular material (89) and/or powder is supplied just before the conveyor (32, 43, 84, 86).
6. Device for producing a fibrous web (29, 33, 34, 88) for the production of filter sticks (40) of the tobacco processing industry, with at least two separating devices (10, 80), by means of which fibres (27, 90) of at least one type of filter material can be separated, wherein a conveyor shaft (82) is provided for each separating device (10, 80), wherein the separating devices (10, 80) are formed separately from one another, characterised in that the conveyer shafts (82) are brought together downstream at the end in a chamber (87), wherein a conveyor (32, 43, 84, 86) is provided, this being disposed downstream of the separating devices (10, 80) and following the chamber (87) and formed in order to shower on separated fibres (27, 90) to form a fibrous web (29, 33, 34, 88).
7. Device according to Claim 6, characterised in that the separating devices (10, 80) in each case comprise at least one separating element (21, 26, 76, 81), the axis of rotation (91) of which is oriented substantially parallel to the conveying direction (92) of the conveyor (34, 43, 84, 86).
8. Device according to Claim 6 or 7, characterised in that the at least two separating devices (10, 80) are disposed above the conveyor (32, 34, 84, 86).

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