EP2217749B1 - Apparatus for transporting fibre material between a drafting arrangement and a mesh-forming machine, and circular knitting machine equipped with said apparatus - Google Patents

Description

The invention relates to a device of the type specified in the preamble of claim 1 and a circular knitting machine equipped therewith

Devices of this type are known in particular in connection with so-called spinning knitting machines, ie eg circular knitting machines ( PCT WO 2004/079 068 A2 . DE 10 2006 006 502 Al . DE 10 2005 044 082 A1 ), which work with largely untwisted fiber materials instead of conventional yarns. The fiber material used for knitting is immediately after its exit from a drafting with the help of a so-called swirl member having a spinning or transporting device into a temporary yarn
transformed, whereby the temporary rotation of the fiber material is maintained during the entire transport process. The transport of the temporary yarn is preferably carried out in a transport pipe connected to the twisting element. For longer transport routes, which are usually desirable in order to arrange the drafting systems with a comparatively large distance from the stitch-forming machine, several, formed by a respective swirler and a transport tube transport units are connected in series. In order to achieve a uniform fiber transport, it is also common to leave a gap between two successive transport units of this type, which serves to reduce the required for the production of rotations compressed air streams. This makes it possible on the one hand to transport the fiber material despite its low strength compared to conventional yarns over long distances from the drafting system to an associated system of a stitch forming machine, in particular a circular knitting machine, as is achieved by this artifice that formed into a temporary Gam Fiber material meets all strength requirements during transport and there is no risk of it dissolving or cracking. On the other hand, the rotations imparted to the fibrous material in the temporary yarn are loop-formed over the short distance from the exit end of the conveyor to the subject system Machine degraded again to zero (false-twist principle), so that the processed to mesh fiber material is not made of a twisted yarn, but from substantially untwisted, mutually parallel staple fibers. As a result, a knit fabric having extreme softness is obtained as the final product.

A disadvantage of the transport described is that dirt particles, nits, short and foreign fibers and other, loosely adhering to the fiber material and entrained by this foreign body can lead to errors in the knitwear and soiling of the mesh formation organs. Unlike normal spinning are no winder od. Like. Exists, detected by means of which impurities and other defects in the fiber material and possibly can be eliminated by cutting the temporary yarn and subsequent splicing.

Therefore, devices of the type described at the outset have already been proposed ( DE 10 2007 018 369 ), which in each case have a ventilation element in the gaps between successive transport units, which forms a substantially closed system with the outlets and inlets of the transport units adjoining each other in the gaps and, in addition to the venting, primarily serves to clean and unwind the fiber material. This ensures that foreign particles are detected in the region of the gap and removed from the fiber stream. However, in the practical testing of such a system, it has been found that essentially only the light particles are removed from the fiber stream, whereas heavier particles, in particular so-called shell parts, remain in the fiber stream and are therefore ultimately incorporated into the fabric with the fiber material. In addition, this type of cleaning is bought with the disadvantage that the entire transport path from the drafting to mesh-forming machine forms not only a closed, but also a rigid, less flexible system, which is connected to an additional manifold and the work on the stitch-forming machine can hamper.

From the DE 36 31 400 A1 a device for pneumatic false twist spinning is known, the upstream of the false twist nozzle having an air nozzle and a suction nozzle, wherein the air nozzle serves to deflect the fiber strand and the suction nozzle at the deflection point at the outlet of the air nozzle serves to spread loose fiber ends of the strand.

In contrast, the technical problem of the present invention is to design the initially described device so that it is easier to handle, can be easily adapted to the needs of the case and allows even more effective cleaning of the fiber stream.

This problem is solved according to the invention in that a suction device is arranged in the region of the open gap forming the ventilation opening.

It has surprisingly been found that the suction device leads to a much more effective cleaning of the fiber stream or temporary yarn when it is operated in the manner of an open system, for. B. is arranged below the gap formed between two transport units and thereby additionally the natural gravity of existing dirt particles and the like. Exploits. In particular, it is advantageously possible to carry out the suction with such a low negative pressure that thereby the transport of the fiber material in the transport units is not affected, as could be the case with the use of blown air ventilation devices of the case. It also results in an advantageous manner that the lighter particles are removed as before by the suction from the fiber stream, while at the same time the heavier particles such. B. shell particles are ejected through the open gap and then z. B. fall down by gravity. The fiber stream passing through the suction device is thereby released much more effectively than interfering components when a closed system is used. Finally, it is also advantageous that the suction device can adjoin an open gap, ie. H. no closed system is needed for the air duct, which facilitates access to the various components.

Further advantageous features of the invention will become apparent from the dependent claims.

• Fig. 1 schematisch eine Vorrichtung zum Transport von Fasermaterial zwischen einem Streckwerk und einer maschenbildenden Maschine;
• Fig. 2 einen schematischen Längsschnitt durch eine aus einem Drallorgan und einem Transportrohr gebildete Transporteinheit der Vorrichtung nach Fig. 1;
• Fig. 3 eine perspektivische Ansicht der Vorrichtung nach Fig. 1 gemäß einem ersten Ausführungsbeispiel der Erfindung;
• Fig. 4 Einzelheiten der Vorrichtung nach Fig. 3;
• Fig. 5 bis 8 verschiedene, erfindungsgemäß ausgebildete Transporteinheiten für die Vorrichtung nach Fig. 3 und 4; und
• Fig. 9 einen Längsschnitt durch eine Vorrichtung nach Fig. 1 gemäß einem zweiten Ausführungsbeispiel der Erfindung.

The invention will be explained in more detail below in connection with the accompanying drawings of exemplary embodiments. Show it:

• Fig. 1 schematically a device for transporting fiber material between a drafting and a stitch forming machine;
• Fig. 2 a schematic longitudinal section through a formed of a swirl member and a transport tube transport unit of the device according to Fig. 1 ;
• Fig. 3 a perspective view of the device according to Fig. 1 according to a first embodiment of the invention;
• Fig. 4 Details of the device according to Fig. 3 ;
• Fig. 5 to 8 various, inventively designed transport units for the device according to Fig. 3 and 4 ; and
• Fig. 9 a longitudinal section through a device according to Fig. 1 according to a second embodiment of the invention.

Fig. 1 shows roughly schematically in a vertical partial section a stitch-forming machine in the form of a circular knitting machine 1 with a needle cylinder 2, are slidably mounted in the usual knitting needles 3, which at a designated below as a knitting knitting with the aid of lock parts, not shown in a for receiving fiber material suitable receiving position can be moved. The circular knitting machine 1, the z. B. can be configured as a right / left circular knitting machine, stands on an indicated by the reference numeral 5 bottom of a hall or a knitting room. From the hall floor 5, an operator can operate the knitting machine 1. In addition, 5 more cans 6 are parked on the hall floor, in which existing fibers 7 Lunten are stored.

The Lunten 7 are od over conveyor belts 8. The like. A drafting 9 supplied, which is accessible to the operator of a above the hall floor 5 arranged working platform 10 from. Each of a variety of knitting systems, from those in Fig. 1 only one is shown, such a drafting 9 is assigned, which in a conventional manner z. B. has three pairs of drafting rollers 11. In addition, each knitting system, if necessary, an auxiliary thread 12 are supplied, which is withdrawn from a supply spool 14. The auxiliary thread 12 can either directly by means of a thread guide directly or, as Fig. 1 shows are fed via an output roller pair 11a of the drafting system 9 the knitting system.

A coming from the drafting 9, not shown fiber strand, which consists of substantially untwisted, mutually parallel staple fibers is, as is more accurate Fig. 2 can be seen, fed to an associated knitting system by means of a generally designated by the reference numeral 15 transport device. The transport device 15 contains at least one swirl element 16 and a spinning or transport tube 17 (FIG. Fig. 2 ), in the embodiment according to Fig. 1 because of the comparatively large distance of the circular knitting machine 1 from the drafting system 9 three transport units, each having a swirl member 16a, 16b, 16c and a transport pipe 17a, 17b, 17c, are connected behindereinder. The first swirl element 16a in the transport direction of the fiber material 4 is arranged directly behind the pair of output rollers 11a and the exit section 18 of the drafting system 9, while the last transport tube 17c in the transport direction is arranged close to hooks 19 (FIG. Fig. 2 ) ends at the respective knitting system in the fiber receiving position driven knitting needles 3 ends. Behind the knitting needles 3, a suction element 20 may be arranged, the z. B. is connected to a central suction 21.

Trained as a spinning device transport device 15 or each of twisting body 16 and transport tube 17 existing transport unit is used according to Fig. 2 to first convert the fiber structure delivered by the drafting system 9 into a temporary yarn 22 with real turns. The swirl member 16 is z. B. formed from a substantially hollow cylindrical body 23, the inner cavity z. B. receives the initial portion of the transport tube 17 in itself and terminates flush with this at a front end face 24. From the front page 24 goes at least one air duct 25, preferably a plurality of air ducts 25, all of which are arranged obliquely to a central axis of the transport tube 17. The air ducts 25 pass through the wall of the body 23 and the transport tube 17 and terminate at an inner wall of the transport tube 17. In operation, the ends of the air ducts 25 adjoining the outside of the body 23 are supplied with compressed or blast air by means not shown the swirling member 16 draws the fiber material appearing in the exit nip 18 of the pair of outgoing rollers 11a into the transporting pipe 17 and at the same time also passes it through the transporting pipe 17 in the direction of the knitting system in question. Because of the oblique arrangement of the air ducts 25 also air vortex 26 are generated in the transport tube 17 so that the coming of the output rollers 11a fiber material is not only sucked, but also spun to the temporary yarn 22 by a large number of revolutions are granted, which Compact fiber material at the same time. The temporary yarn 22 retains the rotations substantially to the end of the transport tube 17, whereupon these rotations are then dissolved again until the fiber material 4 enters the knitting needles 3, ie they are reduced to zero (false-twist effect). Therefore, a compacted but almost untwisted fiber material 4 enters the knitting needles 3. The same effect is obtained when according to Fig. 1 three transport units from twisting organs and transport tubes 16a / 17a to 16c / 17c are connected in series. These transport units may be in accordance with Fig. 1 be arranged with preselected angles relative to each other, whereby it is possible to transport the refined, coming from the drafting 9 fiber material over relatively long distances without being damaged.

Between each two successive transport units of the required for generating a vortex compressed air flow is discharged through vents to the outside, through column 27 ( Fig. 1 ) between an exit end 28 of a preceding transport unit (eg 16a, 17a) and an entry end 29 of a subsequent transport unit (eg 16b, 17b).

Circular knitting machines of the type described are z. B. from the documents PCT WO 2004/079 068 A2 and DE 10 2006 006 502 A1 which are hereby made the subject of the present disclosure in order to avoid repetition by reference to them.

Fig. 3 shows analogously to Fig. 1 a drafting system 9, in contrast to Fig. 1 two adjacent transport paths for fiber material and therefore each have two adjacent transport units 16a, 17a and 16b, 17b and 16c, 17c. In addition, only the lower rollers 11, 11a of the drafting system 9 are shown to simplify the illustration. Finally shows Fig. 3 one each at the end of each last transport tube 17c arranged yarn guide 30 through which the supplied fiber material 4 the knitting needles 3 is supplied ( Fig. 2 ).

According to the invention and according to Fig. 3 is in the region of at least one vent or the gap forming them, preferably in the region of all gaps 27a, 27b, etc. arranged at least one suction device 31a, 31b. This preferably includes a suction tube, the one close to one end and with particular advantage from below to the relevant gap 27a, 27b extends and connected to another end to a suction or vacuum source, not shown. The suction power of the suction source is preferably selected so that directly at the respective gap 27 a, 27 b, a negative pressure of z. B. 20 mbar to 50 mbar below the ambient air pressure. As a result, an effective liberation of the fiber stream or the temporary yarn 22 is achieved by impurities carried in this. Incidentally, it is clear that the negative pressure in the regions adjoining the gaps 27a, 27b takes into account the blowing air emerging from them and the blowing air generated by the respective swirling element (eg 16a) and the suction capacity of the swirling element adjacent to the relevant gap 27a, 27b (For example, 16b) should be adjusted so that on the one hand achieves a favorable cleaning effect and on the other hand, the transport of the temporary yarn 22 when passing through the gaps 27a, 27b and the remaining sections of the transport route is not affected.

The suction devices 31a, 31b or suction tubes can, as Fig. 3 and 4 show, at least in the region of their suction openings are perpendicular to a transport direction v predetermined by the transport tubes 17a to 17c, as in Fig. 4 is indicated by a central axis 32b of the suction device 31b. However, it may also be expedient to arrange the suction devices obliquely to the transport direction v . Is in Fig. 4 indicated that the suction device 31a also shown in dashed lines positions 31a1 and 31a2 with axes 32a1, 32a2 can take. An inclination corresponding to the axis 32a1 is z. B. useful when an outlet end 28a of adjacent to the relevant gap 27a transport unit 16a, 17a bevelled and provided with an oblique front or end face 33a and one of the suction device 31a has facing outlet opening whose axis z. B. extends coaxially to the axis 32a1. However, this beveling of the exit end 28a is not achieved by the transport tube 17a being bent at the respective end. Rather, preferably a straight tube is cut obliquely at its end to form the end face 33a (FIG. Fig. 4 ), so that the axes of successive tubes can be aligned in a continuous manner.

Due to the chamfer, an enlargement of the free opening and thereby of the space available for suction at the outlet end of the respective transport tube 17 is achieved, which is why in this case the length of the gap 27 measured in the transport direction v can be reduced.

The angle at which the end surface 33a is inclined relative to the axis of the transfer tube 17a may be different, as in FIG Fig. 4 a comparison with an inclined end face 33b at the outlet end of the transport tube 17b shows.

Fig. 4 Thus, as a whole, an embodiment with an obliquely downwardly pointing end face (eg 33a in FIG Fig. 4 ) in combination with an attached from below to this suction device 31, z. B. in the position 31a2. Loose entrained particles are particularly easily excreted from the fiber stream or temporary yarn 22 in this case, assisted by gravity.

Other possible embodiments for the formation of the transport tubes 17 at their outlet ends are made Fig. 5 to 8 seen. Further explanations appear unnecessary.

A further advantageous embodiment can be obtained in that the oblique end faces 33a are directed to the side and the axes of the suction devices 31 are horizontal rather than horizontal Fig. 4 be arranged vertically. As a result, an undesired sagging of the fiber material in the region of the gap 27a, 27b can be largely avoided. Finally, sloping outlet ends have the advantage that they predetermine a preferred direction for the excess air to be removed, thereby automatically directing them away from the subsequent inlet opening.

Furthermore, it has proved to be expedient with regard to the desired cleaning effect to measure the lengths x1, x2 (x) measured in the transport direction v (FIG. Fig. 4 ) of the gaps 27a, 27b neither too large nor too small to choose. A dimension 0 <x ≦ 2di, in which di denotes the inner diameter of the transport tube 17a, 17b preceding the respective gap 27a, 27b, is considered particularly advantageous. The dimension x is determined from the outermost edge of the preceding transport tube (eg 17a) to the beginning of the inlet opening 29 (FIG. Fig. 1 ) of the subsequent transfer tube (eg, 17b), such as Fig. 4 clearly shows. In this case, the inlet end of the subsequent transport tube through this itself, as in Fig. 1 is indicated, or also by the inlet opening of a swirl member (eg 16b) connected to the respective transport tube. That depends on the particular construction and z. B. depends on whether the twisting element is arranged in front of the inlet end of the transport tube or is penetrated over its entire length from the transport tube. Overall, therefore, the length x indicates the smallest distance between two transport units each consisting of a swirl element 16 and a transport tube 17.

Moreover, the application of the dimensions 0 <x ≦ 2di has the advantage that, after a break of the temporary yarn 22 or an emptying of a transport unit 16, 17 For other reasons no problems arise when re-piecing and the forming yarn 22 is automatically threaded into the inlet opening of each subsequent transport unit.

In particular Fig. 1 . 3 and 4 show, the transport tubes 17a, 17b and 17c preferably all straight straight central axes. Also shows Fig. 1 a variant in which at least one transport tube 17c is arranged at an angle to the other transport tubes 17a, 17b, although all tube axes are in alignment. According to the embodiment Fig. 3 In addition, all three transport tubes 17a, 17b and 17c are arranged coaxially with each other. On the other hand shows Fig. 4 a particularly preferred embodiment for the purposes of the invention, which has a significant feature.

This peculiarity consists in that the transport tubes 17a to 17c, while considered individually, have a constant internal diameter throughout, but these internal diameters gradually become smaller from the drafting device 9 in the direction of the knitting machine 1. In particular, the transport tube 17a has the largest, the transport tube 17b has a central and the transport tube 17c the smallest inner diameter. Thereby, the advantage is achieved that the transport line formed from the transport tubes 17a, 17b, and 17c has a comparatively large inner diameter at the beginning and a comparatively small inner diameter at the end. The large initial diameter favors an undisturbed adoption of the fiber stream coming from the drafting system 9, while the small final diameter favors the undisturbed insertion of the fiber stream 4 into the knitting needles 3. In this case, the gap 27a, 27b between successive transport units 16, 17 expediently dimensioned so large that of the amount of air exiting from the preceding, larger inner diameter transport units, only as much is transferred to the subsequent transport units, as these due Their smaller inner diameter can accommodate.

It is particularly advantageous if the transition from an in the transport direction v preceding, first transport unit (eg 16a, 17a) to an immediately following, second transport unit (eg 16b, 17b) is chosen to be larger than the transition from this second transport unit (eg 16b, 17b) to one another subsequent third transport unit (eg 16c, 17c). In this case, the temporary yarn 22 in the first transport tube 17a forms a comparatively large balloon, which promotes good separation of the entrained foreign particles in the subsequent, first gap 27a. As a result, most of the contaminants are already removed in the region of this gap 27a. Therefore, subsequent transport tubes, in particular in the transport direction v respectively last transport tubes 17c receive a correspondingly reduced inner diameter, whereby the balloon formation is smaller and a tighter guidance is achieved, which is advantageous for a clean insertion of the fiber material in the knitting needles.

A further advantageous embodiment ( Fig. 4 ) provides, although the transport tubes 17a, 17b and 17c all straight form and arrange with mutually parallel axes, however, to provide a transversely to the transport direction v extended offset between the axes of successive transport tubes. As Fig. 4 shows, z. B. between the axes of the transport tubes 17 a and 17 b, an offset or distance A1 and between the axes of the transport tubes 17 b and 17 c offset A2. It is expedient in the embodiment A1> A2, since the inner diameter of the transport tubes 17a, 17b, 17c in the direction of the knitting machine 1 is getting smaller. An advantage of the offset A is that it can be compensated by him in a simple way geometrical positional differences between the drafting system output and the input hole of the yarn guide 30; without having to bend one of the transport tubes 17. The size of the offset is to be selected on the basis of the individual case and should at usual inner diameters of the transport tubes of z. B. 1.5 mm to 4 mm smaller than or at most as large as half the inner diameter of each subsequent transport tube. The direction of the offset A may be such that a subsequent transport tube offset by the offset A laterally or up or down relative to a preceding tube, the particular position in particular also based on the in the columns 27a, 27b prevailing air conditions to choose.

Fig. 9 shows another preferred and currently considered best embodiment of the invention, in contrast to Fig. 4 only two transport units, each with a swirl element 35a, 35b and a transport pipe 36a, 36b connected thereto are shown, although three or more transport units could also be present here. The parts 35a, 36a form here a preceding and the parts 35b, 36b a subsequent transport unit. Between an exit end 37 of the preceding transport unit 35a, 36a and an entry end 38 of the subsequent transport unit 35b, 36b, an open gap 39 is provided, which is intended to form a vent opening. In the region of this gap 39, a suction device 40 is arranged. This points contrary to Fig. 4 a suction chamber 42 connected to a suction pipe 41, which is closed off by a first end wall 42a and a second end wall 42b which expediently lies parallel thereto, which are arranged substantially perpendicular to the transport direction of the fiber material and at a distance from one another. The transport tube 36a of the preceding transport unit projects through a passage of the first end wall 42a and extends with its free, the outlet end 37 forming end portion to the gap 39 and arranged there second end wall 42b. This end wall 42b is provided with an exit opening 43 opposite the entry end 38a of the following transport unit, whose inner cross section is larger than the outer cross section of the transport tube 36a of the preceding transport unit at this point.

As Fig. 9 shows the free end portion of the transport tube 36 a, the outlet opening 43 in particular protrude in such a way that its outermost edge, the analogous to Fig. 4 with the beginning of the inlet opening 38 determines the length x of the gap 39, slightly protrudes outwardly beyond the inlet opening 37 and projects into the gap 39, as Fig. 9 clearly shows. By these measures is surprisingly achieved that the swirled with loose fibers, exiting from the transport tube 36a and bouncing on the subsequent swirl member 35b and 36b transporting air into the between the annular peripheral gap formed formed the edge of the outlet opening 43 and the transport tube 36a and then od together with any, especially lighter lint, impurities. The like. Is discharged through the suction pipe 41. At the same time, heavier particles are expelled through the open gap 39 and removed from the fiber stream entering the subsequent swirl organ 35b. This results in an effective cleaning as in the other embodiments described.

Especially good is the cleaning effect when the transport tube 36 a z. B. is sealed by means of an O-ring 44 in the first end wall 42a and therefore the suction of the suction pipe 41 almost exclusively in the area between the edge of the outlet opening 43 and the transport tube 36a is effective.

Thus, the suction chamber 42 can be easily manufactured and opened and cleaned if necessary, the second end wall 42b is expediently designed as a sealed and releasably connected to the suction chamber 42 lid. For sealing, a further O-ring 45 can expediently serve. At the same time, it is achieved with the aid of the O-rings 44, 45 that the suction chamber 42 can be formed as an all-round closed housing, except for the suction tube 41 and the gap 39 between the end wall 42b and the transport tube 36a 38 of the following transport unit 35b, 36b facing with distance.

Corresponding extraction chambers 42 can be provided at the transitions between further transport units, not shown.

Incidentally, the off Fig. 9 apparent transport units analogous to those according to Fig. 1 to 8 be constructed.

The invention is not limited to the described embodiments, which can be modified in many ways. For example, the described and apparent from the drawing angle at which the end faces are chamfered at the outlet ends of the transport units, to be considered as examples, which may be departed from as appropriate. The same applies to the angles between successive transport units (eg 16b, 17b and 16c, 17c in FIG Fig. 1 ). Furthermore, the transport tubes 17 and 36 can have other than the here implicitly assumed, circular inner contours. If the contours deviate from the circular shape, it is expedient to use the dimension of the mean inner diameter of a transport tube as a measure. Further, it may be appropriate to use transport tubes whose inner diameter gradually from the inlet openings in the direction of the Austrittsöffinungen, z. B. conical, decrease. Further, other than the described, in particular also mechanical twist elements can be used. Further, transport tubes may be used, the inner shells are provided with at least one spiral groove, thereby to improve the rotation of the temporary yarn in the transport tubes, wherein the pitch of the grooves should be selected depending on which rotations are given by the twisting organs. Furthermore, the transport devices described can also be provided on other stitch-forming machines than the described circular knitting machines. Finally, it is understood that the various features may be applied in combinations other than those described and illustrated.

Claims (15)

1. Apparatus for transporting fibre material between a drafting arrangement (9) and a mesh-forming machine (1), comprising at least two transport units which are disposed one behind the other in a transport direction (v) and have respectively one inlet end (29, 37) and one outlet end (28, 38) and which are formed from respectively one twisting member (16a, 16b, 16c, 35a, 35b) and a transport pipe (17a, 17b, 17c, 36a, 36b) which is connected to the latter, an open gap (27a, 27b, 39) which is intended for forming a vent being provided between one outlet end (28, 37) of a preceding transport unit and the inlet end (29, 38) of a subsequent transport unit, characterised in that, in the region of the gap (27a, 27b, 39), a suction device (31a, 31b, 40) which is open towards the latter is disposed.
2. Apparatus according to claim 1, characterised in that the gap (27, 27b, 39) has a smallest length x, measured in the transport direction (v), which satisfies the inequation 0 < x ≤ 2di, di being the internal diameter at the outlet end (28, 37) of the preceding transport unit.
3. Apparatus according to claim 1 or 2, characterised in that the transport pipes (17a, 17b, 17c, 36a, 36b), viewed in the transport direction (v), have increasingly smaller internal diameters.
4. Apparatus according to one of the claims 1 to 3, characterised in that the outlet end (28a) of at least one transport unit (16a, 17a) is provided with an outlet opening which extends diagonally to the axis thereof.
5. Apparatus according to one of the claims 1 to 4, characterised in that the transport pipes (17a, 17b, 17c, 36a, 36b) have axes which extend parallel to each other.
6. Apparatus according to claim 5, characterised in that the axes of two successive transport pipes (17a, 17b, 17c) are disposed with a preselected offset (A1, A2) which is extended transversely to the transport direction (v).
7. Apparatus according to claim 6, characterised in that the offset (A1, A2) is at most equal to half the internal diameter of the respectively subsequent transport pipe.
8. Apparatus according to one of the claims 1 to 7, characterised in that the suction device comprises a suction pipe (31 a, 31 b, 40).
9. Apparatus according to claim 8, characterised in that the suction pipe (31a) has an axis (32a1, 32a2) which extends diagonally to the transport direction (v).
10. Apparatus according to one of the claims 4 to 9, characterised in that the suction pipe (31a, 31 b) comprises an outlet opening which is chamfered and orientated towards the gap (27a, 27b).
11. Apparatus according to one of the claims 1 to 10, characterised in that the axes of successive transport pipes (17b, 17c) together form an angle.
12. Apparatus according to one of the claims 1 to 11, characterised in that the suction device (40) has a suction chamber (42), connected to a suction pipe (41), with a first end wall (42a) and a second end wall (42b) which is situated opposite the latter, the transport pipe (36a) of the preceding transport unit protruding into a passage of the first end wall (42a) and being extended up to the second end wall (42b) which has, in the region of the gap (39), an outlet opening (43), which is situated opposite the inlet end (38) of the subsequent transport unit, with an internal cross-section which is greater than the outer cross-section of the transport pipe (36a) of the preceding transport unit at this position.
13. Apparatus according to claim 12, characterised in that the transport pipe (36a) of the preceding transport unit is disposed sealed in the first end wall (42a).
14. Apparatus according to one of the claims 12 or 13, characterised in that the second end wall (42b) is configured as a cover which is connected in a sealed and detachable manner to the suction chamber (42).
15. Circular knitting machine, characterised in that it is provided with at least one apparatus according to one or more of claims 1 to 14.

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