DE1532046B2 - Method and device for the production of non-covered continuous strands of filamentary or fibrous material, preferably for tobacco filters - Google Patents

Description

The invention relates to a method and a device for the production of uncovered, continuous strands of filamentary or fibrous material, preferably for tobacco filters Gluing the threads or fibers by means of a heat-activatable binder, in which the Thread or fiber material by means of an endless belt through a tubular heating chamber is promoted.

It is already known (FR-PS 1373 693) the threads or fibers provided with a plasticizer to pull through a steam-heated nozzle, 'which surrounds the entire strand, while the Threads or fibers are glued together. Here, the outer surface of the strand is through the Smoothed inner surface of the nozzle. By the one required for pulling the strand through the nozzle However, tension can reduce the crimp of the threads or fibers, thereby reducing the quality of the strands because of the associated reduction in their resistance to radial deformation would be adversely affected in an undesirable manner for the subsequent processing. One uses therefore the strands produced by this process are primarily intended for felt-tip pens, which have it In contrast to cigarette filters, dimensional stability is not essential.

The object of the invention is to provide non-covered continuous strands of filamentary or fiber-shaped Preferably to produce material for tobacco filters that are dimensionally stable that the circumference of the

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Strand of threads or fibers has a precisely reproducible value. This is particularly the case Cigarette filters of particular importance. Here must namely the extent of the filled with tobacco Sleeve and filter match exactly so that around the end of the tobacco-filled sleeve and the tipping paper placed there on the filter does not compress the filter in such a way that it becomes Creases or grooves can form in the surface area of the filter, through which tobacco in this area could flow through without being exposed to the filter effect. The procedure must also be conducted in this way that there is no reduction in the crimp of the individual threads or fibers, because this also significantly reduces the filter effect.

It is already known to solve this problem by making a paper-wrapped strand of threads or fibers with its sheath passed through a heating chamber (US Pat. No. 3,039,908).

With this measure, however, the filter receives an additional coating of paper, which once is not necessary and, on the other hand, is also undesirable, because it prevents the gaseous from penetrating Heating medium is unnecessarily hindered in the line.

These deficiencies are thereby solved while at the same time solving the problem on which the invention is based eliminates the fact that a gas-permeable belt is used as an endless belt and the strand is wrapped with it and is shaped so that this covered strand is passed through the heating chamber and there one that Tape and the strand is exposed to transversely penetrating gaseous heat carrier, and that after the gluing 'of the thread or fiber material, the tape is removed from the strand.

The transport of a strand through a heating chamber by means of a belt is already a part of it to the state of the art, but here the tape only serves as a support for the strand and is impermeable, thus not to be used at all within the meaning of the invention (cf. US Pat. No. 3,050,430).

Preferably, cooling is provided by the strand after heating and before removal of the tape Gas passed through.

In a further embodiment of the invention, after the finished, dimensionally stable strand is formed Air flow resistance measured continuously and the weight to keep the measured value constant controlled per unit length of the thread material to be processed into the strand.

The shaped and heated strand can also be post-formed in a further embodiment of the invention will.

In the case of not completely closed edges of the tape between these exiting Fadenbzw. In a further embodiment of the invention, fiber material is expediently between the heating and the cooling stage to remove the rib that has formed into the interior of the strand.

In a further embodiment of the invention, the strand being formed can also have a filter effect improving additive can be incorporated in a mixture with a thermoplastic binder.

In the case of a strand of cellulose acetate fibers, it is expedient to use it as an additive particles of coal mixed with particles of polyethylene.

A device for carrying out the method according to the invention with a one feed line for a heating chamber with a heating medium through which an endless, driven belt runs, is essentially characterized in that the belt is permeable, a conveying means for the fiber or thread material and a guide are provided which deforms the tape so that it envelops the strand.

ίο A cooling chamber is useful behind the heating chamber arranged. The passage cross-section of the cooling chamber is expediently smaller for reshaping chosen as that of the heating chamber.

In a further embodiment of the invention is between the heating chamber and the cooling chamber and between the adjacent longitudinal edges of the tape advantageously a preferably adjustable pressure foot intended.

The speed of feed rollers for the Faao Den- or fiber material is expediently passed through a measuring device that measures the air flow resistance of the strand Control device.

The passage of the heating chamber and / or the cooling chamber advantageously opens out via a longitudinal section for inserting or removing the tape to the outside, and it is a device for sealing this longitudinal slot is provided along its length.

This device for sealing the longitudinal slot has parallel to the passage for the The strand and the tape have an auxiliary bore forming an axial widening of the longitudinal slot, in which an expandable hose is housed, which is connected to a pressure medium source that can be switched on and off is.

A device for changing the cross section of the passage of the cooling chamber is advantageous intended. ...

The drawing shows in _:

F i g. 1 is a schematic side view of an apparatus for performing the method according to FIG Invention,

F i g. FIG. 2 shows an enlarged section from the device according to FIG. 1 _,:

F i g. 3 shows a plan view of the in FIG. 2 shown Detail,, ·. ...

FIG. 4 is an end view of the section according to FIG. 3 with the device for adjusting the tongue body ,: ■ '::: ■■■:'. ( Fig. 5 is a section along the line 5-5 of Fig. 3,

F i g. 6 shows a section along the line 6-6 of FIG. ;

7 shows a section along the line: 7-7 of the F i g. 3, and in ...

8 shows a section through a modified, preferred Embodiment of part of the device. :. · ■■ · ■■,

In the case of the described embodiment of the method according to the invention is used as a thread or fiber material is a tow made of secondary cellulose acetate and triacetin as a binding agent or adhesive used. According to FIG. 1, a bale 1 becomes a tow 2 of rolls 3 through a nozzle 4 and over a cylindrical guide 5 drawn. Another nozzle 7 forms the tow passed on by the pair of rollers 6 to a tape about 250 mm wide before it enters a box 10 in which it is sprayed by spray guns 8 and 9 with the triacetin is sprayed.

5 6

The nozzles 4 and 7 have the usual shape and path from the roller 24 back to the drum 20

each have a narrow slot through which it becomes a cylinder open in the longitudinal direction

Tow runs through it. One of the side walls has a narrow gap between the edges of the opening

this slot is perforated and is deformed with a tongue. When leaving the cooling chamber 28

line for compressed air in connection. On the other side, the deformed band opens again and loosens

ten wall is solid and holds the tow back from the strand. The perforations in the tape are sufficient

while the air hits this. Through the out, steam and air can easily flow through and

Passage through the rollers 11 will allow the ribbon shape to enter the filaments or fibers. the

of the tow as it passes under the applicator 12, the final shape of the surface of the strand is from.

maintained, which has a container 13, depending on the surface properties of the tape,

which contains an additive which is pressed against the tape on one of the threads of the tow

inclined vibrating chute 14 is noticeable through which the Zu- while it is under the action of the

Substitute are evenly on the steam formed from the tow in a softened state. If a

Volume is distributed. If such an additive is not required to have a deeply embossed surface of the strand,

is to be applied, the machine can also 15 can be a coarse-woven belt, and if a smooth one

work without using the applicator 12. The surface to be created is a finely woven

Tow then runs through the funnel 15, to be used in tape. Through the perforation

which it receives a cylindrical shape before there is a loosening of fibers from the peripheral surface

runs under a tongue 16, which prevents the individual in that of the strand, without one of the surrounding

F i g. 3 and 4 is shown. Through this tongue, the threads lying on the strand are additionally clogged.

the tow is introduced into the heating chamber 18 and must be used.

at the same time a permeable band 19 around the cylinder- if desired, the tow through-

drical tow lying around. This permeable band, running hole of the heating chamber slightly larger than

which be through the drum 20 through the heating chamber- the cooling chamber. Then the latter serves to

mer 18 is pulled through, in order then to 35 the strand to the desired final diameter

Running reels 21, 22, 23 and 24 is open. Bring it knife. By the action of the steam

can be made of a polyamide fabric or single thread on the surface of the threads made of cellulose

Polyethylene terephthalate exist. The tape can be coated with acetate in the places where triacetin droplets sit.

a coating made of a silicone resin or of polycene, local adhesive points. As a result of the ho-

tetrafluoroethylene to prevent adherence of the latent heat of condensation of the steam

To prevent Tows from him. In the heating chamber 18 the cellulose acetate and the triacetin very much

opens up to a supply line via inlet openings, so that when the tow reaches the heating

device for steam connected line 25, via chamber 18 leaves the fibers or threads in the we-

which the steam in the heating chamber 18 and are completely glued to each other through essential,

the permeable band enters the tow, 35 The amount of steam supplied is dependent on

this heats up the bonding of the threads or the speed of the forward movement of the

Cellulose acetate fibers are set together by the tow through the machine. To achieve

Triacetin causes. the necessary gluing is only a very

Because the threads or fibers stick together, an amount of steam is required. For example

stands a strand 26. The longitudinal edges of the strand 40 are a satisfactory gluing of the threads

surrounding tape 19 are generally or fibers of a tow of about 0.5 cm ² cross-section,

not completely in contact with each other, so that the speed of 117 m / min,

some threads or fibers of the tow moved between them, by a steam rate of about 18 kg / h

Edges are squeezed out and a kind of under a pressure which is only slightly above the at-

Form rib. This rib is due to an in-between atmospheric pressure. Here the binding

see the pressure foot 27 lying at the edges of the band, i.e. the triacetin, activated by the steam.

removed, which presses on the rib and so fourth, while the ίϊ carried by the band

forms the strand cylindrical again. The strand runs Tow in an untensioned condition. Under the- [

then through a cooling chamber 28, in which the line 30 per Mi-,

line 30 introduces air or another gas 50 utes about 5501 air at room temperature, the

which flows through the band, in contact with means from 21 to 29 ° C, with a pressure of 1.8

reaches the threads or fibers of the strand 26, this atm supplied to cool and harden the strand

cools and any condensation formed in this strand, so that it is now cut and further treated.

sat removed from him. Preferably, the flow can be cooled without the risk of

The air flows through the tape to several over which it is damaged or destroyed as a result.

Length of the cooling chamber 28 at a distance from each other because the continuous strand is not made of paper

lying places through it. After flowing through it is enveloped, one can have a continuously working one

the air with the device for measuring the pressure drop, e.g. B. the

if necessary entrained condensate in a recording in F i g. 1 shown apparatus 33 for determination

receiving container 17, which in the direction of 60 of the flow resistance of the continuous

is ventilated backwards with respect to the machine. Use strand 26. This device 33 has

The action of this air takes place at the same time, for example, the pressure gauge 35, which is through

a further consolidation of the strand. After leaving a linkage 34 indicated by dashed lines with the

Sen of the cooling chamber 28 the strand passes an output of the rollers 3 is connected. With that, the

cutting device 29, which cuts it into sections 65 feed speed of the tow 2 automatically

disassembled. and continuously depending on all changes

Belt 19 resists pressure drop as it rests around drum 20 rolls 21 to 24 runs flat. On his state of strand 26 changed and such an im

essential constant pressure drop characteristics are maintained. This automatic control can by changing the rotational speed of the rollers 3 in approximately the opposite proportion to the changes in the pressure drop and thus the amount of crimp of the threads, i.e. the weight of the tow per unit of length.

In the finished cigarette, the new filter bodies are usually filled with the one filled with tobacco Sleeve part through a piece of tipping paper lying around, e.g. B. cork sheet connected, which encloses the entire length of the filter and 2 to 3 mm of the tobacco-filled tube. This kind the way the filter is attached differs from the usual way of attaching filter cigarettes, in which the filter consists of a core body enclosed by a thin wrapping paper exists to which the tipping paper is glued. The core body with a thin paper wrapping can shrink during storage and also when smoking, creating a gap between them the core and the thin paper wrapping through which smoke can flow without being filtered will. This possibility is excluded with cigarette filters manufactured according to the invention. Further can glue the relatively thick mouthpiece paper so well with the filter be connected that this mechanically shrinks the filter body when smoking is prevented.

The strands made according to the invention are primarily for use as cigarette filters intended, but can also be used for other purposes, e.g. as an absorbent body for the ink for felt-tip pens or as a filter for luminous gas or water.

The implementation of the process according to the invention is explained in detail in the following examples.

ίο Example 1

The in Fig. The method illustrated in Figure 1 was carried out using a tow of cellulose acetate threads at a tow speed of approximately 117 m / min. After the tow had been converted into tape form, about 10 percent by weight of triacetin, based on the weight of the tow, was sprayed onto the thin thread web and the tow, now provided with the plasticizer, was shaped into a circular cross-section of about 0.5 cm ² . Steam was then blown into the tow in the steam treatment chamber in an amount of about 11 kg / h and the longitudinal rib initially formed in the tow when it was reshaped into a cylindrical shape was removed by pressing. Then, the formed strand was cooled with about 550 liters of air at 24 ° C with a pressure of 1.8 atm.

The continuous strand was cut into individual filter rods 80 mm in length, which after one Storage times of 24 and 72 hours were investigated. The following values were found:

Table 1

State of examination weight of
10 bars in
Gram acetate
including
lubricant
»/ 0 Plasticizers
° / o water
Vo All in all
»/ 0 Immediately after manufacture
lung 5.95
5.85
,, 5.77 82.3
83.8
84.6 10.0
10.2
10.0 7.7
6.0
5.4 100.0
100.0
100.0 After 24 hours After 72 hours! ..

The values in the table above show a reduction in the water content during storage. However, it is possible to change the final water content by changing The characteristics of the cooling chamber and the relative humidity of the storage room.

The following results were obtained with filter rods whose moisture content is in equilibrium with the atmospheric moisture.

Table 2

Type of investigation On average Maximum-
value Minimal-
value Weight of 10 bars
in grams
Pressure drop in cmWS ..
Scope in now
length in mm 5.85
12.2
24.55
79.7 5.95
13.0
24.65
79.8 5.75
11.2
24.45
79.5

Example 2

Example 1 was repeated, but using the method from FIG. 1 can be seen Applicator introduced about 30 percent by volume of finely divided carbon powder. This made the Filter effect especially on the components of tobacco smoke present in the vapor phase of the cigarette provided with the filter as a result of the higher absorbing properties of this additive improved.

Example 3

It was also shown in FIG. 1 used, but the spray guns 8 and 9 were switched off. In the reservoirs 13 is a homogeneous mixture of activated carbon particles has been mm and having a particle size of 0.3 to 0.8 m polyethylene particles introduced with an average diameter of about 50 x 10 ~. ⁶ The Ver-

409 550/125

9 10

ratio of the weights of these two components to that in the longitudinal bore 51

carried about 75 per cent coal and 25 per cent polyethylene. The area of the tow and ribbon is attached.

After switching on the system, about 25 times were The longitudinal bore 51 is aligned in the axial direction weight percentage of this mixture by means of the applicator with the tapered one between the tongue gate 12 on a tow made of cellulose acetate threads 5 body 16 and the groove in the feed block 41 brought and through the tow in the passageway formed in Example 1, and also with a written way steam and air passed through. Bore 54 of the cooling chamber 28. The diameter The result was a well-glued one, this additional component of the longitudinal bore 51 can be approximately the same diameter strand containing nents. of the space between the smaller ends of the

F i g. 2 and 3 show the essential features of the tongue body 16 and the feed block 41 of one another preferred embodiment. From these fi- forms is, correspond and equal or slightly larger It can be seen that different parts of this than that of the bore of the cooling chamber 28 can be seen. the Attachment of a long common support body chamber 53 can be any suitable Ge-40 be worn by a U-shaped cross-section, have on stalt, but must in any case have a soft the heating and cooling chamber, the tongue passage of sufficient cross-section for the body and the device for pressing in the supply line for the steam and a sufficient rib are stored. The support body 40 can have a number of openings 52, which allow access a system, of which only the band, that of the steam through the permeable band under only Drum and rollers are shown allowing low pressure worn. According to a becoming as is the feature of this arrangement borrowed from systems for making films is common per se, so this support auxiliary bore 55 is provided, which has a body in place of the slot 56 usually associated with the main bore 51 in connection turned load-bearing elements occurs. Which is also pending.

F i g. 1 and the cutting device shown. The bore 55 extends through the heating chamber drive for the band are of the usual training. 25 mer and the cooling chamber through and stands with the A line 39 to the atmosphere is connected to the receiving box 17 via a further slot 57 of condensate and a line 49, the bond. The slots 56 and 57 extend across with a suction pump for better deduction of the total length of the associated holes and Cooling air is connectable, connected. These for the are dimensioned so that the endless belt 19 through them Operation of the new method required 30 run through into the bores 51 and 54 Adjustments are simple and can only cause. As a result, the tape can be easily inserted into the ring costs. Heating chamber and introduced into the cooling chamber

From Fig. 3 and 4 is an in the support body 40 before the operation begins and after the

stored feed block 41 with a closed after operation can be taken out without

Above widening open groove recognizable. A 35 that a slotted block body can be used

Rib 42 with an L-shaped cross section bears the must, otherwise because of the endless belt

arched tongue body 16. The rib 42 and thus would be required.

also the tongue body 16 are held by two on the in order to allow steam to escape through the slot

To prevent support body 40 mounted support members 43 and 44 ge 56, is in the bore 56 after

wear. Of these, the support member 44 can 40 by inserting the tape into the longitudinal bore 51

Adjusting screws 45 adjusted in the vertical direction and hose 58 made of heat-resistant polyvinyl chloride

by means of the screws 46 in the set position or other appropriately selected deformable

be clamped. The horizontal adjustable plastic materials are used, by

of the rib 42 and thus of the tongue body 16 extend a pressure medium and thereby

follows by adjusting screws 47. The screw 48 is 45 in contact with the walls of the bore 55

by the rib 42 after this adjustment on the brought. The end of this hose extends

Support member 44 clamped. The tongue body 16 through the bore to a clamp 59 through

forms with the groove of the feed block 41 one which it is compressed and thereby closed.

tapering, the tow leading and its sen, whereupon the print medium in the opposite '

Cross-section at its entry into the heating chamber 50 initiated the end of the hose set, this here-

18 decreasing passage canal. The path of the extended through and thereby during operation

Tape 19 extends so that its edges maintain the tight seal over the bes of the system

Tips of the tongue body run and so is selected.

rend of passing through the heating chamber 18 under ent- As a result of this after the assembly of the heating}

It is not a speaking deformation of the band that comes together in a tight seal

or come close to each other. With regard to the- required, for the purpose of introducing and c

This feature is an essential difference removing the band 19 other parts of the front π

as opposed to the guidance of the bands, which dismantle during the preparation, as the hose 58. To the ν

Position of paper-wrapped filter rods at the end of the hose 58 can be a bend 60 from S.

be turned. 60 metal. Even the one between the heating

As shown in detail in FIGS. 3 and 5 can be seen chamber and the cooling chamber lying area of the

is, the heating chamber 18 consists of one in the hose 58 of one also from FIG. 6 result

Support body 40 mounted block 50, which enclosed a visible metal bushing 61, by i,

Longitudinal bore 51 for the passage through the tow, which causes an undesirable expansion of this part

and the band 19 surrounding it. 65 of the hose while under the action of the in

The longitudinal bore 51 stands over openings 52 with the same introduced pressure medium to prevent

a chamber 53 in connection, to which their- the. These precautions are only in the

on the other hand, the line 25 is required for the supply of the steam in the vicinity of the heating chamber. at

11 12

Room temperature makes it the resistance of the and the tape in the receiving device 17 over Hose against radial expansion superfluous, a slot 82 allows, which is about the to take such measures. The bore 54 is the total length of the cooling block 66 and below dimensioned so that the bushing 61 pleases on the part of the supporting body 40 which is located for the same purpose Place on the hose 58 slipped 5 stretches.

ben can be before this is in the bores 51 on the support body 40 of a U-shaped profile

and 54 is used. The possibility of expansion, as can be seen from FIG. 3, is also the outlet block

of the hose 58 and the diameter of the bore 83, which, as already noted above,

gen 51 and 54 are chosen so that this is possible an upwardly widening groove open at the top

is. ίο, the presence of which means the separation of the

From FIGS. 3 and 6, the formation of the pre-strip 19 is facilitated by the rod strand 26,
direction 27 for removing the from the circumference of the From the cross-section according to FIG the steam heating chamber 18 pre-leaves 15 change in the circumference of the main bore. This device consists of a pressure device of the diameter of the rod strand that causes a slight change in the pressure of the rib. As 55, which is loaded on a part of the cooling block 66 at its end adjacent to the steam heating chamber 18 when compared with FIGS. 1 and 8, the main difference consists in that in FIG. 8 is shown. The pressure device 65 is adjustable by a pair of ao provided embodiment of the cooling block 66 of these adjusting screws 67, which cooperate with one opposite that in that of its side wall screw 68, which fertilizes in a long way which is opposite the slots 79 and 80 , stretched slot 69 of the pressure device 65 slides a deep groove 85 is provided, and a plurality of screws 86 are penetrated by a plurality of screws 86 above and in a part of the cooling block lying in an upwardly extending this groove part of the cooling block by a part of the cooling block 66 is screwed in. The adjacent remainder of the cooling block, which is screwed into threaded bores 87 in the lower olocks, enables the part of the cooling block lying in the groove 85 to be screwed into the assembly of the pressure device. The between the groove 85 and the cragenen, down between the edges of the lying in bore 51 part 88 of the cooling block 66 is cylindrical shape brought band extending EIe- 30 dimensioned so that it by tightening the screws element 71, which on the possibly existing Rib 86 is bent and thereby the effective diameter of the rod strand presses and in this way it can be enlarged to counter the bore 51,
dwindle brings. Adjacent to each of the screws 86 is a small

The sleeve 61 surrounding the hose 58 in the area of this open screw, part of the device, which is not shown in the figure, is 35 which rests on the lower surface of the groove 85 and is mounted in a groove 72 of the cooling block, which is connected to the upper part of the block 66 is screwed in. Auxiliary hole 55 is aligned. The part 88 in which the box-shaped housing 73 opens into a line 74 in the opposite direction described above, which is connected to another screw on the heating and By loosening the screws 86 and tightening the screws on the cooling chamber and on the support body 40 a suction pump is connected, 40 bent device and thereby the effective diameter and over which both the air from the interior 75 knife of the bore 51 are reduced. Such of the housing 73 sucked out as for example from the changes in the diameter of the bore 51 the heating chamber 18 sucked out steam leaked only for the purpose of determining the diameter of the. Through openings 81, if desired, slightly too external cooling air can be drawn from the cooling chamber rod strand 26 through the slot 82 into the receiving element.
device 17 flow in. In the case of using a cooling block,

From the F i g. 4 and 7 is the design of the cooler. The modified embodiment is required

chamber 28 can be seen in detail. It consists of part of the same on which the rib removal

a cooling block 66 with three holes, of which the device is mounted, not to move when the

the holes 51 and 54 are the main holes for 50 adjustments of the screws. It will

the rod strand and the band and the bore 58 then the screws 86 on which the heating chamber

the auxiliary bore for the sealing tube 58 are. adjacent end omitted. Furthermore, a vertical

Provided by a slot running over almost the entire length of the quay, which the

Bore 77 extending through cooling blocks 66 will connect groove 85 to the top of block 66

Connection to line 30 made of wel- 55 and the one adjacent to the end of the heating chamber

rather compressed air is supplied and cut away through openings 78, the end of the block. In the case of this

are in communication with the bore 51, training is distributed by the movement of the cooling block

is to then through the permeable band and the kes for the purpose of adjusting the position of the

To flow through rod strand and to cool this. Rib removal device, which is then stationary

The slots 79 and 80 allow the insertion 60 remains unaffected.

and removing the endless belt 19 in the A similar adjustment option may be desirable.

The same way as the similarly designed slots must also be provided in the steam supply block the steam heating chamber 18. To the line 30 is hen. The sealing of the auxiliary bore 55 is

a compressed air source, not shown, connected. not affected by such adjustments. she The exit of the cooling air 65 is through openings 81 in this case by further expansion of the and the condensate formed from the string of rods hose 58 secured.

For this purpose 3 sheets of drawings

Claims (15)

532 claims: 1. A process for the production of non-sheathed continuous strands of filamentary or fibrous material, preferably for tobacco smoke filters, by gluing the threads or fibers by means of a heat-activatable binder, in which the thread or fiber material by means of an endless belt through a tubular heating chamber is conveyed, characterized in that a gas-passable belt used as an endless belt and wrapped with it the strand and is shaped such that this overwrapped rod is guided through the heating chamber and there subjected to the band and the strand transversely penetrating gaseous heat carrier, and that after the thread or fiber material has been glued, the tape is removed from the strand, so 2. The method according to claim 1, characterized in that by the strand according to the Heating and cooling gas is passed therethrough before removing the tape. 3. The method according to claim 1 or 2, characterized in that after formation of the finished dimensionally stable strand whose air flow resistance is continuously measured and kept constant of the measured value, the weight per unit length of the thread material to be processed into the strand is controlled. 4. The method according to one or more of claims 1 to 3, characterized in that the shaped and heated strand is reshaped. . 5. The method according to claim 4, characterized in that the case is not complete closed edges of the tape between these emerging thread or fiber material between the heating and cooling stages for removing the formed rib into the interior of the strand is pressed. 6. The method according to one or more of claims 1 to 5, characterized in that the strand being formed is mixed with an additive which improves the filtering effect is incorporated with a thermoplastic binder. 7. The method according to claims, characterized in, that in the case of using a strand of cellulose acetate fibers as Additive carbon particles mixed with polyethylene particles can be used. 8. Apparatus for performing the method according to claim 1, with a one feed line for a heating medium having a heating chamber through which an endless, driven Tape passes through, characterized in that the tape is permeable, a conveyor for the fiber or thread material and a guide are provided which deforms the tape so that it envelops the strand. 9. Device according to claims, characterized in that that a cooling chamber is arranged behind the heating chamber. 10. Apparatus according to claim 8 and 9 for performing the method according to claim 4, characterized in that for reshaping the passage cross-section of the cooling chamber (28) is smaller than that of the heating chamber (18). 11. Device according to claims 8, 9 or 10, for performing the method according to Claim 5, characterized in that between the heating chamber and the cooling chamber and a preferably adjustable one between the adjacent longitudinal edges of the tape Pressure foot is provided. 12. Device according to claims 8 to 11, characterized in that the air flow resistance of the strand measuring device controls the speed of feed rollers (3) for the thread or fiber material. 13. The device according to one or more of claims 8 to 12, characterized in that the passage of the heating chamber and / or cooling chamber via a longitudinal slot for insertion or removing the tape to the outside and a device for sealing this longitudinal slot is provided along its length. 14. The device according to claim 13, characterized in that the device for sealing of the longitudinal slot parallel to the passage for the strand and the tape one axial widening of the longitudinal slot forming auxiliary bore in which an expandable Hose is housed, which is connected to an on and off pressure medium source. 15. The device according to claim 13 or 14, characterized by a device (85, 86, 87) to change the cross section of the passage (51) of the cooling chamber (Fig. 8).