EP1404910B2 - Device for compression crimping - Google Patents

Abstract

The invention relates to a device for the compression crimping of a synthetic multifilament yarn, said device comprising a transport nozzle and a compression chamber. Said transport nozzle comprises a yarn channel by which means a yarn is guided to a compression chamber. Said compression chamber forms a section having a gas-permeable chamber wall, between a yarn inlet and an enmeshment outlet. According to the invention, the gas-permeable chamber wall comprises a friction surface consisting of material which is resistant to wear, on the inner side facing the yarn enmeshment. The constancy of the braking action produced by the friction on the yarn enmeshment can thus be significantly improved.

Description

The invention relates to a device for compression crimping of a synthetic multifilament yarn according to the preamble of claim 1.

A generic device is for example from the EP 0 554 642 A1 known.

For upsetting crimping of a multifilament yarn, the known device has a delivery nozzle and a stuffer box arranged downstream of the delivery nozzle. Here, the thread is conveyed by means of the delivery nozzle in the stuffer box, compressed to a yarn plug and curled. The delivery nozzle is supplied with a delivery medium, preferably a hot gas, which requires the thread within a thread channel to the stuffer box. Within the stuffer box, the thread plug is formed. Here, the multifilament lies in loops on the surface of the yarn plug and is compacted by the pumped medium, which can escape from the stuffer box above the yarn plug. For this purpose, the chamber wall of the stuffer box has at the periphery a plurality of slot-shaped openings through which the fluid can escape. In order to obtain a uniform crimping of the thread, the plug formation must take place in the stuffer box with very high uniformity. The frictional forces resulting from the relative movement of the yarn plug in the stuffer box have a significant influence on the texturing process. There is an equilibrium of forces between the conveying action or the dynamic pressure effect of the conveying medium flowing out of the thread channel of the delivery nozzle and the braking effect on the thread stopper caused by the frictional forces. By adjusting a delivery pressure or by setting an additional suction of the pumped medium, the conveying effect can be essentially determined. In contrast, the braking effect generated by the friction between the yarn plug and the chamber wall depends essentially on the nature of the chamber wall. At the time of the EP 0 554 642 A1 known device, in particular in the section with gas-permeable wall due to the slot-shaped openings only small friction surfaces available. As a result, signs of wear with increasing operating time are inevitable, which leads to a change in the braking effect. When the braking effect decreases, however, it can come to the point that the yarn plug is conveyed out of the stuffer box due to low frictional forces. The texturing process then breaks down. In contrast, with increased frictional forces, the yarn plug is no longer or no longer evenly conveyed out of the stuffer box. An uneven ripple of the thread is the result. Likewise, uneven crimping occurs when a stick-slip effect is applied in the stuffer box. These effects can not be controlled even with a stagnation medium counteracting the pumped medium.

JP 04-343727 discloses a Stauchkräuselvorrichtung, in which a yarn is passed through a heating nozzle before entering the stuffer box, in which the crimping, wherein there is no leading to wear of the chamber walls thread plugging.

US 3,808,654 discloses an apparatus for upset crimping a synthetic thread having a stuffer box with chamber walls whose surface is coated with tetrafluoroethylene.

US-A 3,935,621 discloses a device for crimping a synthetic thread by means of a rotating cylinder.

In contrast, it is an object of the invention to develop a device for Stauchkräuseln a synthetic multifilament yarn of the type mentioned in such a way that even in very long periods of operation, a uniform crimping is ensured in the thread.

The object is achieved by a device with the features of claim 1.

Advantageous developments of the invention are defined in the subclaims.

The invention is based on the finding that the deposition of the thread on the thread stopper surface by the forming loops and bows substantially affects the uniformity of the crimps. In order to keep the impact point of the thread on the thread stopper surface on a substantially non-changing height, therefore, the balance of forces between the conveying effect and the braking effect generated by the yarn thread on the thread stop must be kept constant. This can be achieved by the device according to the invention essentially in that the gas-permeable chamber wall has a friction surface made of a wear-resistant material on the inside facing the yarn plug inside. Thus, a change in the frictional forces is not possible even for very long periods of operation. The invention thus has the advantage that the plug formation can be controlled solely by monitoring the pumped medium by, for example, pressure monitoring.

The wear-resistant material on the surface of the chamber wall can basically be formed by two variants. In a first particularly advantageous development of the invention, the friction surface is formed by a coating applied to the surface of the chamber wall. This coating could for example consist of a ceramic material or a chromium oxide or a carbon coating. However, it is also possible to manufacture the chamber wall made of aluminum in order subsequently to form wear protection by means of a hard-oxide layer.

In a further particularly preferred embodiment of the invention, the friction surface is made by the chamber wall made of a ceramic material educated. For this purpose, the chamber wall can be produced for example from ceramic materials such as zirconium oxide or aluminum oxide or a combination of both.

When using ceramic coatings or ceramic materials is also achieved that the gas-permeable wall is resistant to corrosion and little susceptible to contamination. In particular, deposits can be avoided by preparation residues. Even after a maintenance break the same friction conditions are achieved when switching on the device when starting the device.

However, particularly advantageous is the formation of the gas-permeable chamber wall by a plurality of fins, which are arranged at a distance from each other in an annular manner. Thus, when ceramic lamellae were used, it was observed that by reducing the coefficients of friction, the thread was subjected to less thermal and mechanical stress.

In order to avoid wear within the stuffer box at all coming into contact with the yarn plug walls, according to an advantageous embodiment of the invention according to claim 4, another section with a closed chamber wall also on the side facing the yarn plug inside with a contact surface formed from a wear-resistant material.

The contact surface could be formed by a coating applied to the surface of the chamber wall or by the chamber wall made of a ceramic material.

It has been observed that when using a delivery nozzle with a ceramic wall at least in partial areas of the contact surfaces to the thread according to the embodiment of claim 7, the thread tension reduction in the delivery nozzle was reduced by the friction of the thread to the wall. This can then be achieved at the same delivery pressure a higher yarn tension, which has a higher reliability of the texturing process result, or a yarn tension level can be achieved with lower pressure, with a lower discharge pressure leads to a lower consumption of the fluid. The wear-resistant material of the contact surfaces within the delivery nozzle may be formed by coatings or by ceramic base materials. Thus, the delivery nozzle can also be advantageously made entirely of a ceramic.

In a further embodiment variant of the invention, the inlet of the thread channel in the delivery nozzle is formed by a guide insert. The guide insert, which may be made of a ceramic material or could carry on its surface a coating forms an extension of the thread channel an inlet channel. As a result, in particular the wear on entry of the thread is avoided in the delivery nozzle. When using ceramic materials or ceramic coatings can also realize a very low-friction guidance of the thread.

The delivery nozzle could also have a guide insert forming the outlet of the thread channel which is also made of a ceramic material or has a coating on its surface. The thread leaves the delivery nozzle through an outlet channel of the guide insert.

To convey the thread, a conveying medium, preferably hot air or hot gas, is fed into the thread channel. In order to obtain even at very high flow velocities, which may be in the range of the speed of sound, no washouts in the thread channel, the air inlet is formed in the thread channel by a guide insert according to an advantageous embodiment of the invention. In addition to the air inlet, the guide insert contains a guide channel, which is aligned in extension of the thread channel. The guide insert also consists of a ceramic material or carries a coating on its surface.

Since the fluid flowing into the thread channel leads to a sudden dynamic loading of the thread, the advantageous development of the invention according to claim 11 is preferred to use, in which the guide insert has an additional insert in the inlet region of the guide channel in the air inlet. This can stabilize the thread guide and avoid in the thread returning disturbing influences.

For guiding and treating the yarn plug of the stuffer box at the stopper outlet downstream of a cooling device, in some cases between the cooling device and the stuffer box, a conveyor for guiding the yarn plug is provided. In order to avoid premature soiling and adhesion of preparation residues, according to claim 13, a development is proposed in which the conveying means and the cooling device have a coating on the contact surfaces contacted by the thread stopper.

The invention is described in more detail with reference to some embodiments, which are illustrated in the accompanying drawings.

Fig. 1

schematisch ein erstes Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung im Querschnitt;

Fig. 2

schematisch ein weiteres nicht zur Erfindung gehöriges Beispiel einer Vorrichtung zum Stauchkräuseln im Teilquerschnitt;

Fig. 3

schematisch ein Ausführungsbeispiel einer Förderdüse in einer Querschnittansicht.

They show:

Fig. 1

schematically a first embodiment of a device according to the invention in cross section;

Fig. 2

schematically another example not belonging to the invention of a device for Stauchkräuseln in partial cross section;

Fig. 3

schematically an embodiment of a delivery nozzle in a cross-sectional view.

In Fig. 1 schematically a first embodiment of the device according to the invention is shown in a cross section. The device consists of a delivery nozzle 1 and a delivery nozzle 1 downstream compression chamber 2. The delivery nozzle 1 includes a thread channel 3, which forms an outlet 21 at one end and an outlet 24 at the opposite end. The delivery nozzle 1 is connected by a supply line 17 to a pressure source (not shown here). Through an air inlet 16 and a pressure chamber 39, the supply line 17 is connected to the thread channel 3. The air inlet 16 is formed by a plurality of bores, which supplies a conveying medium in the thread running direction, which is indicated by an arrow, the thread channel 3. With the outlet 24 of the thread channel 3 opens into a plug channel 31 of the stuffer box second

The compression chamber 2 is formed by a delivery nozzle 1 facing portion 7.1 with a yarn inlet 5 and a portion 7.1 downstream section 7.2 with a stopper outlet 6. In the section 7.1, a plug channel 31 is formed by a gas-permeable chamber wall 8. The gas-permeable chamber wall 8 includes a plurality of fins 9, which are arranged at a small distance from each other in an annular manner. The lamellae 9 are held by the lamella holder 10.1 at the upper end of the section 7.1 and by the holder 10.2 at the lower end of the section 7.1. The fins 9 and the holders 10.1 and 10.2 are arranged in a housing 11, wherein the housing 11 is closed to the outside and is connected through an opening 32 with a suction 12.

On the side facing a thread plug 13, the lamellae 9 each have a friction surface 14. The lamellae 9 are made of a ceramic material, so that the friction surfaces 14 are made of a low-wear material.

Below the gas-permeable chamber wall 8, a closed chamber wall 15 is provided which forms a plug channel 33. The plug channel 33 is made larger in diameter than the plug channel 31 in the region of the gas-permeable chamber wall 8. The plug channel 33 forms the plug outlet 6 at its end.

This in Fig. 1 illustrated embodiment of the device according to the invention is shown with a threadline to illustrate the function of the device. In this case, the yarn 4 is conveyed through the delivery nozzle 1 in the yarn channel 3 by a conveying medium supplied via the air inlet 16. The thread 4 enters via the inlet 21 in the thread channel 3 a. The conveying medium used is preferably hot air or a hot gas. By the flowing medium at high speed, the yarn 4 is conveyed at high speed to the stuffer box 2. In the process, a thread plug 13 forms in the plug channel 31. The thread 4, which consists of a plurality of filaments is deposited on the surface of the yarn plug 13, so that the filaments form loops and bows. The pumped medium is sucked through between the slats 9 through the opening 32. The thread stopper 13 forming in the stopper channel 31 bears against the friction surfaces 14 of the lamellae 9. The frictional forces and the delivery pressure of the delivery medium acting on the thread stopper 13 are substantially in equilibrium, so that the yarn stop height inside the stopper channel 31 remains essentially the same. Since the fins 9 are made of a ceramic material, the force equilibrium acting on the yarn plug 13 is maintained substantially by keeping the pressure of the pumped medium constant. The yarn plug 13 enters after leaving the plug channel 31 in the plug channel 33, which is formed by the closed chamber wall 15. The closed chamber wall 15, which could be formed, for example, as a tube, serves only to guide the yarn plug 13 to a downstream, not shown cooling device. Here, the plug channel 33 is formed larger than the plug channel 31, so that only small frictional forces acting on the yarn plug 13. Wear protection is therefore unnecessary.

In Fig. 2 is another example not belonging to the invention schematically shown in a cross section. The example is essentially identical in construction to the previous embodiment Fig. 1 , so that only the main differences are shown below. For clarity, the components are provided with the same functions with identical reference numerals.

The delivery nozzle 1 has for additional acceleration of the pumped medium in the thread channel 3 has a narrowest cross section, which is formed directly below the air inlet 16 Thus, the fluid is accelerated to a flow velocity which is higher than the speed of sound. The thread channel 3 opens into the plug channel 32, which is formed by a cylinder body 18. The cylinder body 18 is arranged in the first section 7.1 of the stuffer box 2. The cylinder body 18 has distributed over the circumference a plurality of longitudinal slots 34, whereby the plug channel 31 is connected to a formed by the housing 11 and the cylinder body 18 annular space 35. At the annular space 35, the housing 11 is connected to an exhaust 12 via the opening 32. On the side facing the yarn plug 13, the cylinder body 18 has a coating 19. The coating 19, which forms the friction surface 14 for guiding a yarn plug, preferably consists of a ceramic material. However, metallic hard chrome layers or carbon compounds are also possible. Thus, the cylinder body 18 may also be made of an aluminum material, which receives a friction surface 14 forming aluminum oxide coating. The Longitudinal slots 34 extend at least over a portion of the cylinder body 18th

The second section 7.2 of the stuffer box is formed by the closed chamber wall 15 containing the plug channel 33. The plug channel 33 forms at the end of the plug outlet 6. The closed chamber wall 15 has on the side facing the yarn plug 13 side a contact surface 20, which also carries a wear-resistant coating 35.

The compression chamber 2 is associated with a delivery means 29 directly at the stopper outlet 6, which is formed from two opposing rollers. The conveying means 29 guides the yarn plug 13 to a cooling device 30 arranged below the conveying means 29. The cooling device 30 could be formed, for example, from a cooling drum, at the circumference of which the yarn plug is cooled. Both the conveyor 29 and the cooling device 30 are provided at their contact surfaces 37 and 38 with a coating.

The function of in Fig. 2 The illustrated example is essentially identical to the previous embodiment Fig. 1 , so that was dispensed with the presentation of the threadline. In this case, however, the yarn plug formation is additionally influenced by the conveyor 29.

In Fig. 3 schematically an embodiment of a delivery nozzle is shown in a cross-sectional view, as for example in the embodiment according to Fig. 1 or in the example Fig. 2 could be used. The delivery nozzle is here in Fig. 3.1 in a disassembled state and in Fig. 3.2 shown in a mounted state. The following description applies, insofar as no explicit reference is made to one of the figures, for both figures.

The delivery nozzle 1 has in the region of the inlet 21 in the region of the air inlet 16 and in the region of the outlet 24 in each case an incision 36.1, 36.2 and 36.3.

The cuts 36.1, 36.2 and 36.3 are connected to each other via a thread channel 3. Between the incision 36.1 and 36.2, a pressure chamber 39 is formed in the delivery nozzle 1. The incision 36.1 in the inlet region of the delivery nozzle 1 serves to receive a guide insert 22.1. The Ftihrungseinsatz 22.1 forms an inlet channel 23 which is aligned in extension of the thread channel 3. The guide insert 22.1 is preferably made of a ceramic material. However, it is also possible that in the region of the inlet channel 23 of the guide insert 22.1 carries a coating.

In the recess 36.2 of the guide insert 22.1 is used. The guide insert 22.2 forms on the one hand the air inlet 16, through which the fluid is introduced from the pressure chamber 39 into a guide channel 26 of the guide insert 22.2. The guide channel 26 of the Fühungseinsatzes 22.2 is aligned in extension of the thread channel 3 on the inlet side of the guide insert 22 an insert 27 is provided which forms an inlet channel 28. The inlet channel 28 has a smaller diameter than the subsequent guide channel 26. The insert 27 and the guide insert 22.2 can also be advantageously made of a ceramic material or provided with a coating.

On the outlet side of the delivery nozzle 1, the guide insert 22.3 is embedded in the recess 36.3. The guide insert 22.3 forms an outlet channel 25, which is aligned in extension of the thread channel 3 and the outlet 24 of the delivery nozzle 1 forms. The guide insert 22.3 is also preferably made of a ceramic material

In the Fig. 3 illustrated delivery nozzle consists in particular in the highly stressed by the thread contact points and friction points of a wear-resistant material, so that a stable and uniform yarn guide and yarn delivery is achieved. In addition, the coefficients of friction between the thread and the contact points or friction points are considerably reduced.

In the in the FIGS. 1 to 3 It should also be noted that the delivery nozzle 1 and the stuffer box 2 are preferably each formed from two halves which are non-positively connected to each other during operation. In principle, however, it is also possible to provide one-piece delivery nozzles and compression chambers with corresponding ceramic inserts or coatings. Regardless of the design of the device, however, it is also possible to produce the areas of the device contacted by the thread each made of a full ceramic or of a coated aluminum material. The device according to the invention is thus characterized in particular by high wear protection and thus stable friction conditions as well as insensitivity to preparations of the thread as well as a considerable extension of the cleaning cycles due to the insensitivity to soiling. Thus, with a device according to the invention a factor of 3 to 5 higher life was achieved. When using the device according to the invention with ceramic materials or ceramic material coatings, the crimping of the thread over a much longer period compared to conventional crimping devices could be kept constant. Thus, a much higher production reliability is achieved.

LIST OF REFERENCE NUMBERS

1

feed nozzle

2

stuffer

3

thread channel

4

thread

5

yarn inlet

6

plug outlet

7

section

8th

gas permeable chamber wall

9

lamella

10

Blade support

11

casing

12

suction

13

yarn plug

14

friction surface

15

closed chamber wall

16

air inlet

17

supply line

18

cylinder body

19

coating

20

contact area

21

Inlet

22

guide insert

23

inlet channel

24

outlet

25

outlet channel

26

guide channel

27

inlay

28

inlet channel

29

funding

30

cooling device

31

plug channel

32

openings

33

plug channel

34

longitudinal slot

35

coating

36

incision

37

contact area

38

contact area

39

pressure chamber

Claims (11)

1. Device to stuffer box compress a synthetic, multifilament yarn (4) with a conveying nozzle (1) that comprises a yarn channel (3) to guide and con-vey the yarn (4), and with a stuffer box (2), arranged at the end of the yarn channel (3) to form and collect a yarn plug (13), which comprises a yarn inlet (5) and a plug outlet (6) and which comprises a section (7.1) with a gas-permeable chamber wall (8) between the yarn inlet (5) and the plug outlet (6), characterized in that the gas-permeable chamber wall (8) is formed by a plurality of blades (9) arranged in a ring-shape with little separation distance from each other and comprises a friction surface (14) made of wear-resistant material on the inner side facing the yarn plug (13), whereby the contact surfaces contacted by the yarn within the conveying nozzle (1) are at least partially formed from a wear-resistant material in the form of a coating or a ceramic material.
2. Device according to claim 1, characterized in that the friction surface (14) is formed by a coating (19) applied to the surface of the chamber wall (8).
3. Device according to claim 1, characterized in that the chamber wall (8) consists of a ceramic material that forms the friction surface (14) on the surface of chamber wall (8).
4. Device according to one of the preceding claims, characterized in that the stuffer box (2) comprises an additional section (7.2) with an enclosed chamber wall (15), which is downstream from the section (7.1) with the gas-permeable chamber wall (8), and that the enclosed chamber wall (15) comprises a contact surface (20) made of wear-resistant material on the inner side facing the yarn plug (13).
5. Device according to claim 4, characterized in that the contact surface (20) is formed by a coating (35) applied on the surface of the chamber wall (15).
6. Device according to claim 5, characterized in that the chamber wall (15) consists of a ceramic material that forms the contact surface (20) on the surface of the chamber wall (15).
7. Device according to claim 1, characterized in that the conveying nozzle (1) comprises a guide insert (22.1) forming the inlet (21) of the yarn channel (3), said guide insert (22.1) forms an intake channel (23) arranged as an extension of the yarn channel (3) and that the guide insert (22.1) is manufactured out of ceramic material or carries a coating on its surface.
8. Device according to claims 1 or 7, characterized in that the conveying nozzle (1) comprises a guide insert (22.3) forming the outlet (24) of the yarn channel (3), said guide insert (22.3) forms an outlet channel (25) arranged as an extension of the yarn channel (3), and that the guide insert (22.3) is manufactured from a ceramic material or carries a coating on its surface.
9. Device according to one of the claims 1, 7 or 8, characterized in that the conveying nozzle (1) comprises a guide insert (22.2) forming the air inlet (16) into the yarn channel (3), said guide insert (22.2) forms a guide channel (26) arranged as an extension of the yarn channel (3), and that the guide insert (22.2) is manufactured from a ceramic material or carries a coating on its surface.
10. Device according to claim 9, characterized in that the guide insert (22.2) comprises an insert (27) forming the inlet of the guide channel (26), said insert (27) forms an intake channel (28) arranged as an extension of guide channel (26), and that the insert (27) is manufactured from a ceramic material or carries a coating on its surface.
11. Device according to one of the claims 1 to 10, characterized in that a conveying device (29) and/or a cooling device (30) are arranged downstream from the stuffer box (2) in the yarn's direction of travel, and that the conveying device (29) and the cooling device (30) comprise a coating on the contact surfaces (37, 38) contacted by the yarn plug.

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