EP0982418B1 - Apparatus and method for stufferbox crimping a synthetic yarn - Google Patents

Abstract

An apparatus and a method of stuffer box crimping a synthetic multifilament yarn, wherein the yarn is advanced in a conveying nozzle by means of a heated conveying gas into a stuffer box and compressed to a yarn plug. At the outlet of the stuffer box, a pair of rolls form a conveying gap for advancing the yarn plug and which has a width smaller than the cross section of the plug leaving the stuffer box so as to compress the yarn plug. The internal passage of the stuffer box is constructed with a cross section that increases in the direction of advance in such a manner that no significant cohesive force develops on the yarn plug, and the resistance to the forward pressure in the yarn plug resulting from the heated conveying gas is provided essentially only by the force on the yarn plug generated by its compression in the conveying gap.

Description

The invention relates to a device for compression crimping of a synthetic multifilament yarn according to the preamble of claim 1 and a method for crimping a synthetic thread according to the preamble of the claim 16th

The device and the method are known from DE 26 32 082.

In compression crimping, a multifilament yarn is fed into a bowl by means of a delivery nozzle Encouraged stuffer box, compressed to a thread stopper and curled. The delivery nozzle is for this purpose with a funding, preferably a hot Gas, which forces the thread within a thread channel to the stuffer box promotes. Within the stuffer box, the thread plug is formed. Here, the thread lays in loops on the surface of the yarn plug and is compacted by the conveyor which is above the yarn plug can escape from the stuffer box through slots. The yarn plug will then guided out of the stuffer box and by means of a subsequent cooling device cooled. After cooling, the thread plug becomes crimped Thread dissolved.

The rippling of the thread is in this case decisive by the Plug formation and influenced by the thermal treatment of the thread plug. To form the yarn plug in the stuffer box is therefore opposite the delivery pressure of the conveying means a holding force or counterforce on the yarn plug generated. In order to keep education and treatment as consistent as possible To allow the thread plug, now has a certain relationship between the delivery pressure and the counterforce are met.

From DE 26 32 082 a device and a method are known in which the drag comes from the friction between the thread plug and the Stuffer box wall and from the conveying speed of the output of the Stuffer box arranged roller pair determined. This is where the problem occurs on that the surfaces of the stuffer box wall with increasing transit time change due to wear in their friction behavior, what inevitably results in a change in the opposing force.

From EP 0 554 642, for example, a device is known in which the counterforce to the stopper formation exclusively from the friction between the But this results in that already after short term, the opposing force changes. Constant adjustment measures are inevitable here.

US 3,827,113 discloses a texturing process for a plurality of surfaces a compression chamber with a constant cross section in the conveying direction.

Accordingly, it is an object of the invention, the known device and the known A method of upset crimping a synthetic multifilament yarn in such a way educate that a uniform formation of the yarn plug and a uniform thermal treatment of the yarn plug is guaranteed.

Another object of the invention is to provide a yarn plug with a lint-free Produce filament composite.

The object is achieved by a device having the features according to claim 1 and solved by a method having the features according to claim 16.

The invention is characterized in that regardless of the surface finish and the wear of the thread-guiding or stuffing-leading Components essentially always the same conditions for the treatment of the yarn plug available. To the influence of the friction between the yarn plug and to minimize the compression chamber wall, the device of the invention a compression chamber with increasing in the conveying direction cross-section. In order to the plug is substantially free of resistance without substantial holding power passed through the stuffer box. The cross-sectional enlargement can be infinitely variable or in stages. To the back pressure required for plug formation build up, the pair of rollers at the output of the stuffer box one Delivery gap on, which has a width s, which is smaller than the plug diameter D when exiting the stuffer box. The plug diameter D is thereby determined by the cross section of the stuffer box in the inlet region. The inlet area the stuffer box extends substantially from the entrance to the Stuffer box to the beginning of the air outlet openings, preferably as Longitudinal slots are formed in the chamber wall. In relation to the total length the stuffer box is the inlet area in the upper half, preferably in the upper third or upper quarter of the stuffer box. By the narrow conveying gap between the rollers, the plug is essentially compressed transversely to its conveying direction. The counterforce thus depends on the Peripheral speed of the roller pair of the cross-sectional change of the Thread stopper off. With uniform delivery pressure and uniform peripheral speed of the roller pair is thus a substantially constant Counterpressure for plugging generated, which is independent of the Surface texture and wear of the plug-leading components.

The additional compression of the yarn plug also causes the crimping positively influenced in intensity in the thread. Already at a compression of At least 10% of this effect can be seen. Here has the conveying gap of the roller pair has a minimum width s of about 90% of the plug diameter. Preferably, the conveying gap of the roller pair is set to a width s, which is less than 60% of the plug diameter D, ie s <0.6 * D. With that you can Compressions of the plug in the conveying gap of over 30% can be achieved.

To the acting in the area of the compression chamber on the plug by friction Holding force to minimize the stuffer box is advantageously designed conical, so that the cross section of the stuffer box increases continuously. in this connection is an opening angle of the stuffer box of at least 2 °, preferably at least 5 °, but preferably less than 10 ° provided.

To build up a relatively high back pressure to form the yarn plug, the embodiment of the invention according to claim 4 is particularly advantageous.

A particularly preferred embodiment of the invention according to claim 5 or 6 has the advantage that the yarn plug at a uniform speed without slippage between the roller pair and the thread plug from the stuffer box is encouraged. In addition, due to the rough surface structure on the circumference the rollers achieved a secure engagement with the yarn plug. The thread plug is evenly compressed in cross section and safely through the pair of rollers promoted without a slip between the thread plug and one of the Rolling of the roller pair occurs.

Particularly advantageous is the formation of the device according to the invention, in which the surface structure of the rollers is formed as a toothing. It may be both a straight and a helical toothing. Thus, the surface of the yarn plug is additionally broken, which in particular, improves the subsequent cooling of the yarn plug.

The development of the device according to the invention according to claim 8 is in particular suitable for setting the conveying direction. For rolls with the same large trained circumference in the contact area to the thread plug is the same Drive speed of the rollers a particularly straight conveying direction of the plug reached. In contrast, by uneven large trained peripheral areas he rolls a kinking run of the yarn plug can be achieved. additionally when conveying the plug with different diameters of the rollers the yarn plug due to the different peripheral speeds and Wraps loosened up, which in particular during the subsequent cooling leads to a uniform and more intense cooling of the yarn plug.

In order to be able to optimally adjust the thread plug formation when the process starts up, the device according to claim 9 offers the possibility of the peripheral speed to change the rolls. This can be essentially the Dwell time of the thread plug inside the compression chamber influence. in this connection There is also the option of both rolls with the same or different Driving speeds.

In a further particularly preferred embodiment of the device according to Claim 11, it is possible to change the back pressure. This is at least one of the rollers of the roller pair in their position changeable. In order to can reduce the width of the conveying gap to increase the back pressure or be increased to reduce the back pressure.

In a particularly advantageous embodiment of the device according to claim 12, the thread at a very high flow rate in the stuffer box be encouraged. For example, in the narrowest point of the thread channel the conveyor to a speed close to the speed of sound accelerated, so allows the formation of the thread channel, that the flow velocity approximately until reaching the stuffer box stops. Within the stuffer box then takes place an expansion of the conveyor. Due to the high flow rate is also achieved that within the compression chamber of the plug in the conveying direction increasing cross-section evenly fills the stuffer box.

The invention according to claim 14 shows a particularly preferred embodiment the device. Here, the stuffer box is through a wall with in the conveying direction increasing wall thickness formed so that the stuffer box to the outside has a conical shape. In the wall are several evenly on the circumference arranged distributed longitudinal slots arranged, the wall parallel to the conveying direction penetrate. This configuration of the stuffer box is in particular allows the production of a lint-free yarn. It is known that in the expansion of the conveyor immediately at the entrance to the stuffer box Individual filaments of the thread are blown into the longitudinal slots. By the conical stuffer box with increasing in the conveying direction Wall thickness, the individual filaments are safe with progressive thread plug and fed evenly into the thread plug. The from the stuffer box emerging yarn plug thus has no protruding individual filaments and is particularly characterized by a stable filament composite.

To cool evenly after the heat treatment, the thread plug and Thus, to fix the crimp, the yarn plug with a through the roll surface formed compression surface over the cooling surface of the cooling drum guided. As a result, on the one hand over the entire thread cross-section achieved uniform contact with the cooling device and on the other uniform flow through the plug with a cooling medium.

Further advantageous developments of the invention are described in the subclaims Are defined.

An embodiment is described below with reference to the attached Drawings described in more detail.

Fig. 1

schematisch eine Schnittansicht eines ersten Ausführungsbeispiels der erfindungsgemäßen Vorrichtung;

Fig. 2

eine Draufsicht auf ein Walzenpaar zum Stauchen eines Fadenstopfens;

Fig. 3

schematisch eine Schnittansicht eines weiteren Ausführungsbeispiels der erfindungsgemäßen Vorrichtung ohne Kühleinrich- tung;

Fig. 4

schematisch eine Schnittansicht eines weiteren Ausführungsbeispiels der erfindungsgemäßen Vorrichtung.

They show:

Fig. 1

schematically a sectional view of a first embodiment of the device according to the invention;

Fig. 2

a plan view of a pair of rollers for upsetting a yarn plug;

Fig. 3

schematically a sectional view of another embodiment of the device according to the invention without cooling device;

Fig. 4

schematically a sectional view of another embodiment of the device according to the invention.

In Fig. 1 is a first embodiment of a device for Stauchkräuseln a synthetic thread shown. The device initially consists of a Delivery nozzle 1 with a central thread channel 3. The central thread channel 3 is in this case as in the device known from EP 0 539 808. in this respect is referred to this document.

The thread channel here consists essentially of two sections that through a narrowest cross-section are separated. In the first section just before the narrowest cross section open several nozzle holes 5 in the Threaded channel 3. The nozzle bores 5 are connected to an annular chamber 6. The annular chamber 6 is via the supply line 4 with a pressure medium supply (here not shown).

In the second section below the narrowest cross section, the thread channel expands 3 with a very small opening angle, preferably in the range from 0.5 ° to 5 °. At the end of the thread channel 3 closes immediately the Stuffer box 7 at. The stuffer box 7 is through the stuffer box wall. 8 educated. Here, the compression chamber in the entrance area has a comparison to the thread channel slightly larger cross section, in the conveying direction to the Exit of the yarn plug substantially continuously expanded. For this is the Stauchkammerwand inside tapered executed with an opening angle of> 2 °, preferably> 5 °. The Stauchkammerwand 8 is through a plurality of evenly distributed on the circumference longitudinal slots 14 penetrated. The longitudinal slots 14 extend substantially over the entire length of the stuffer box 7. To the outside is the stuffer box wall 8 also formed cone-shaped such that adjusts a wall thickness, the in the conveying direction increases. The wall thickness can be both continuous as well as gradually increase in their strength.

Below the stuffer box, a pair of rollers 10 is arranged. The roller pair 10 consists of the rollers 11 and 12. Between the rollers 11 and 12 is a Conveying gap 15 formed. The conveying gap 15 is designed with a width s, the smaller than the plug diameter D (see Fig. 2). The conveying gap is hereby set to a width that is in the range of s <(0.9 * plug diameter D), preferably s <0.6 * plug diameter D is. The rollers 11 and 12 are driven at the same speed.

Below the pair of rollers 10, a cooling device 13 is provided. The Cooling device 13 is in this case designed as a rotating cooling drum, at the Scope of the thread plug 9 is performed for the purpose of cooling up to a The end point. At the drain point, the thread plug 9 is dissolved into a thread.

In the apparatus shown in Fig. 1, the thread 2 by means of a hot Promoted conveyor through the thread channel 3 in the stuffer box 7. For this is the hot conveyor, preferably as hot air or steam over the Nozzle holes 5 introduced into the thread channel 3. At the beginning of the process will be first closed the stuffer box 7 on the outlet side, so that a Plug 9 forms by storing the thread 2 in loops and loops. The end the thread channel 3 at approximate speed of sound escaping funding can via the introduced in the stuffer box wall 7 longitudinal slots 14th exit above the yarn plug. After a yarn plug in the Stuffer box 7 has formed, the stuffer box is opened and the process can start. In this case, the yarn plug first plants up to the conveying gap 15 of the roller pair 10 continues. In the conveying gap 15 of the yarn plug 9 is now compressed between the surfaces of the rollers 11 and 12. By the compression, which is at least 10%, preferably at least 30%, is the formation the thread plug 9 applied in the stuffer box 7 required counterforce. For example, a thread made of polypropylene at a yarn diameter of 5 mm and a conveying gap width of 2 mm advantageously textured become. For example, in a nylon thread, the thread plug was used with a diameter of 4 mm for crimping through a gap of 2 mm guided.

The pair of rollers 10 then promotes the yarn plug 9 to the cooling drum thirteenth The yarn plug 9 wraps around the cooling drum 13 on the circumference. The cooling drum 13 has openings in the jacket to be able to suck in cooling air. The Cooling air flows through the plug. At the end of the cooling section of the yarn plug 9 dissolved to the crimped thread, by means of a delivery mechanism (not shown here) and, for example, a winding device fed.

In Fig. 2 is a plan view is shown schematically on a pair of rollers, as it For example, in the device of FIG. 1 would be used. The roller pair consists of the rollers 11 and 12. The roller 11 is connected via a shaft 19 with the Drive 17 connected. The roller 12 is in a shaft 20 with a drive 18th connected. The rollers 11 and 12 are arranged in a plane opposite and form between them a conveying gap 15. The rollers 11 and 12 are cylindrically shaped, so that the conveying gap over the roll length a substantially constant width s has.

At this point it should be noted that conical or profiled shaping of the Rolling the conveying gap over the roller length with different width executable is.

The rollers shown in Fig. 2 have on the peripheral surface more in the axial Direction extending grooves 16. The grooves 16 are uniform on the circumference the rollers 11 and 12 distributed in the surface introduced. Through the profiled Surface structure of the rollers 11 and 12, which are independent of each other are driven by the drives 17 and 18, the yarn plug 9 is safe detected on its surface and fed into the conveying gap 15. The thread plug 9 has after leaving the stuffer box a substantially circular Cross section with the diameter D. Due to the narrow conveying gap the yarn plug is compressed by the pair of rollers. This will be a change reaches the stuffing density, which improves the subsequent cooling.

The rollers 11 and 12 of the roller pair shown in Fig. 2 are the same size executed and are usually driven at the same speed. Thereby becomes a uniform substantially straightforward promotion of the yarn plug 9 causes. However, it is also possible, the rollers 11 and 12 with different Driving speeds. In this case, the thread plug will exit from the conveying nip in the direction of the roll, the smaller peripheral speed is driven, deflected.

In Fig. 3 is schematically another embodiment of the invention Device shown. The delivery nozzle 1 and the subsequent stuffer box 7 are identical to the embodiment of FIG. 1 executed. In that regard will to the description of FIG. 1 reference.

The delivery nozzle 1 opens with the thread channel 3 in the stuffer box 7. The thread channel 3 is opposite the compression chamber 7 with increasing in the conveying direction Cross section out. Here, the opening angle β in the range of 0.5 ° to 5 °, preferably to 2 °. In Fig. 3, the opening angle in Cross section of the thread channel with ½β entered. Through this education is achieved that the flow rate of the conveyor substantially is maintained along the thread channel. This allows high tensile forces on the Thread to be built. In the subsequent compression chamber 7 of the thread deposited on the plug surface and by the inflowing conveyor in compressed the compression chamber 7.

The stuffer box 7 is formed by the stuffer box wall 8. In Fig. 3 is the stuffer box 7 shown in half section. The stuffer box 7 has from Inlet to the outlet of an increasing cross-section. The thread stopper diameter D is thus formed by the cross section of the stuffer box 7. For this purpose, the stuffer box wall 8 is arranged at an opening angle α. Of the Opening angle α is entered in the half section in Fig. 3 with α / 2. The opening angle α is now formed such that between the stuffer box wall. 8 and the yarn plug 9 no significant holding forces built up by friction become.

The compression chamber wall 8 is formed permeable to air, so that the conveying means can flow out of the stuffer box 7 above the yarn plug. For this are a plurality of substantially parallel to each other arranged longitudinal slots 14 in the stuffer box wall 8 introduced. The longitudinal slots 14 penetrate the Stuffer box wall 8 at least over a partial length of the stuffer box. 7

Due to the outflowing conveyor individual filaments are partly with in the longitudinal slots 9 are retracted. So that the filaments safely in the yarn plug can be retracted, the stuffer box wall 8 is increasing Wall thickness formed.

The yarn plug 9 is conveyed via the pair of rollers 10 from the stuffer box and further conveyed to a cooling device, not shown in Fig. 3. The in Fig. 3 roller pair 10 in turn consists of the rollers 11 and 12th The roller 11 has a toothing on the surface in this embodiment Likewise, a toothing 24 is formed on the circumference of the roller 12. The rollers form between them the conveying gap 15, due to the cylindrical Shape of the rollers 11 and 12 is a substantially constant Width s has. The roller 12 is coupled to an adjusting device 21 and mounted in a guide 22 so that a displacement by the adjustment the conveyor roller is transverse to the conveying direction executable. This can be the conveying gap in its width s change.

By the teeth 23 and 24 on the peripheral surfaces of the rollers 11 and 12, the thread plug despite the compression of its compression surfaces 28 and 29th broken up. In the subsequent cooling, a cooling air flow is transverse to directed to the compression surfaces on the plug. Because of the broken Compression surfaces occurs a much more intense cooling effect at the thread plug, which results in a shortening of the cooling section.

In Fig. 4 is a schematic longitudinal section through a further embodiment the device of the invention shown. The delivery nozzle 1 and the Stuffer box 7 are identical to the embodiment of FIG. 1 executed. In that regard, reference is made to the description of FIG. 1 reference.

In the embodiment shown in Fig. 4 is directly at the output the stuffer box 7, a tube 25 between the stuffer box 7 and the pair of rollers 10 arranged. On the exit side of the tube 25 is the pair of rollers 10 arranged. The pair of rollers 10 consists of the rollers 26 and 27. The rollers form between them the conveying gap 15. The roller 27 is in diameter smaller than the roller 26. Both rollers are at the same speed driven. Due to the smaller circumference of the roller 27 of the yarn plug promoted on the side of the roller 27 at a lower speed. On the opposite side of the yarn plug with the determined by the roller 26 Promoted peripheral speed. The difference between the two Circumferential speeds causes the yarn plug when exiting the Conveying gap 15 is deflected. This diversion is particularly advantageous around the yarn plug with its compression surface on a subsequent rotating Store cooling drum. The speed difference at both compression surfaces the yarn plug also leads to loosening the yarn plug.

In the embodiment shown in Fig. 4, the tube 25 serves to the To increase residence time of the hot thread plug. In particular, one To perform shrinkage treatment of the yarn. This could, for example in addition, the tube 25 may be heated. However, it is also possible, a cross to Direction flowing hot air through a pipe with porous walls to to conduct thermal treatment of the yarn plug.

The embodiments shown in FIGS. 1 to 4 of the invention Device are all suitable for carrying out the method according to the invention. In this case, threads, in particular carpet yarns, made of polyamide, polypropylene or polyester are curled. The yarns stand out in particular through an intense and homogeneous rippling.

Claims (18)

1. Apparatus for stuffer box crimping a synthetic multifilament yarn (2) with a conveying nozzle (1), which comprises a yarn channel (3) for guiding and advancing the yarn (2), with a stuffer box chamber (7) formed at the end of the yarn channel (3) for receiving a yarn plug (9), with a pair of rolls (10) arranged at the outlet of the stuffer box (7) for advancing the yarn plug (9), and with a cooling device (13), characterized in that the stuffer box (7) is constructed with a cross section increasing in the direction of advance such that no significant cohesive force develops on the yarn plug, wherein the yarn plug (9) leaves the stuffer box (7) with a plug diameter (D) that is defined by the cross section in the inlet region of the stuffer box (7), and that the pair of rolls (10) comprises a conveying gap (15) with a width (s) smaller than the plug diameter (s < D).
2. Apparatus of claim 1, characterized in that the conveying gap (15) has a width (s) in the range of s < 0.9 * D, preferably s < 0.6 * D.
3. Apparatus of claim 1 or 2, characterized in that the stuffer box (7) is made conical with an aperture angle greater than 2°, preferably greater than 5°.
4. Apparatus of one of claims 1-3, characterized in that the conveying gap (15) is formed by opposite cylindrical rolls (11,12) of the pair of rolls.
5. Apparatus of one of the foregoing claims, characterized in that the rolls (11, 12) of the pair of rolls (10) exhibit a rough surface structure on their circumference opposite to the yarn plug (9).
6. Apparatus of claim 5, characterized in that the rough surface structure is formed by a plurality of axially directed grooves (16) in the roll surface.
7. Apparatus of claim 5 or 6, characterized in that the rough surface structure is formed by a gear-tooth system (23) in the roll surface.
8. Apparatus of one of claims 1-7, characterized in that in their contact region with the yarn plug (9) the rolls (11,12; 26,27) of the pair of rolls (10) are made circumferentially identical or different.
9. Apparatus of one of claims 1-8, characterized in that at least one roll (11,12; 26,27) of the pair of rolls (10), preferably both rolls (11,12;26,27) can be driven at a variable circumferential speed.
10. Apparatus of claim 9, characterized in that the rolls of the pair of rolls (10) can be driven at the same or different rotational speeds.
11. Apparatus of one of claims 1-10, characterized in that at least one roll (12) of the pair of rolls (10) can be changed in its position for varying the width of the conveying gap (15).
12. Apparatus of one of the foregoing claims, characterized in that the yarn channel (3) has a cross section that continuously increases with a substantially constant aperture angle from a narrowest point to the stuffer box (7).
13. Apparatus of claim 12, characterized in that the aperture angle is from 0.5° to 5°, preferably 0.5° to 2°.
14. Apparatus of one of the foregoing claims or the preamble of claim 1, wherein the wall (8) of the stuffer box (7) comprises a plurality of elongate slots (14) arranged therein in even distribution over the circumference, which slots extend through the wall (8) parallel to the direction of advance, characterized in that the wall (8) of the stuffer box (7) is constructed of a thickness that increases in direction of advance, so that the stuffer box (7) exhibits outwardly a substantially conical shape.
15. Apparatus of one of the foregoing claims, characterized in that the cooling device is a cooling drum (13), and that the yarn plug (9) can be advanced over the cooling surface of the cooling drum (13) with one of its compressed surfaces facing the roll surface.
16. Method of stuffer box crimping a synthetic yarn, wherein the yarn is advanced with a heated gas into a stuffer box, wherein the yarn is compressed inside the stuffer box to a yarn plug, wherein the yarn plug is removed from the stuffer box and deposited on a cooling device, characterized in that the yarn plug is guided without significant cohesive force through the stuffer box having an increasing cross section in direction of advance and that after leaving the stuffer box and before being deposited on the cooling device, the yarn plug is compressed substantially transversely to its direction of advance.
17. Method of claim 16, characterized in that the yarn plug is compressed between two surfaces by at least 10%, preferably at least 30%.
18. Method of claim 16 or 17, characterized in that the compressed yarn plug has a cross section with two compressed surfaces, and that the yarn plug advances over the cooling device with one of its compressed surface in contact therewith.

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