EP1846599B1 - Method and device for crimping a multi-threaded yarn in a stufferbox - Google Patents

Abstract

The invention relates to a method and to a device for crimping a multi-threaded yarn. After extruding a plurality of filaments, the multi-threaded yarn is guided to the crimping chamber, through the yarn channel by means of a conveying fluid and is crimped in the crimping chamber in order to form a thread plug. Said thread plug is detached by withdrawing the crimped yarns. At least one parameter is continuously detected in order to monitor crimping. According to the invention, a structure-borne noise, which is produced in a wall of the yarn channel and /or in a wall of the crimping chamber, is measured as a characteristic value in order to take into account the interaction of several process parameters during crimping. A structure-born noise housing is arranged on a housing component of the compression chamber.

Description

The invention relates to a method for stuffer box crimping of a multifilament yarn according to the preamble of claim 1 and to an apparatus for carrying out the method according to the preamble of claim 10.

A generic method and a generic device are from the EP 1 026 295 A2 known.

In the production of crimped synthetic yarns in a single-stage process, high demands are made, in particular, on the crimping produced in the yarn in terms of uniformity and stability, in order to enable immediate further processing into a flat structure, for example a carpet. In the single-stage production process of crimped yarns, a multiplicity of filaments are first extruded from a polymer melt and combined to form a yarn. To crimp the multifilament yarn is fed to a crimping device having a delivery nozzle and a stuffer box. The delivery nozzle contains a thread channel, in which a delivery fluid flows in at high speed, so that the thread drawn in the thread channel is conveyed by means of the delivery fluid into the adjacent compression chamber. Within the stuffer box, the multifilament thread is laid down to form a thread stop, in which the filaments of the thread condense into loops and bows. After a thermal treatment, the thread plug is released by pulling off the thread, the filaments of the thread maintaining a fixed crimp.

The crimping in the yarn is dependent on a large number of directly interacting process parameters, such as, for example, the conveying speed of the yarn, the delivery pressure of the delivery fluid, the temperature of the delivery fluid, the speed of the yarn stopper, and the withdrawal speed of the crimped yarn Thread etc. depends. Due to the large number of interacting process parameters, simple monitoring and control of the crimping process can not be carried out.

There are thus numerous methods and devices known to produce crimped threads with high crimp quality.

In the EP 1 026 295 are some such methods and devices cited in the publications DE 1 236 126 . DE 23 24 827 and DE 42 24 454 indicated so that to the EP 1 026 295 A2 at this point, reference is made to this. All methods known in the art have in common that the crimping of the thread can not be detected and monitored. But just the rippling of the thread is to be regarded as a relevant characteristic for the further processing process.

That in the EP 1 026 295 A2 The proposed method is based on the monitoring and control of the process at the release point of the yarn plug, which depends essentially on the withdrawal speed of the crimped yarn. Thus, process stabilities and crimp uniformity could be achieved. However, the crimp is significantly affected by the in the crimping caused by the conveying medium yarn plug formation.

It is therefore an object of the invention to provide a method for Stauchkräuseln a multifilament yarn of the generic type and an apparatus for performing the method, with which an immediate monitoring of the crimping relevant yarn plug formation within the crimping device is possible.

Another object of the invention is to provide a method and apparatus for crimping a multifilament yarn in which Product changes can be implemented quickly and without major delays in process changes to stabilize the crimp.

The object is achieved by a method having the features according to claim 1 and by a device having the features according to claim 10.

Advantageous developments of the invention are defined by the features and feature combinations of the respective subclaims.

The invention is characterized in that the interaction of several process parameters for generating the crimping is possible solely by monitoring a single parameter. As a parameter, a structure-borne noise generated in a component of the crimping device is measured. In this case, the structure-borne sound unites all dynamic processes taking place within the crimping device in order to form the multifilament yarn into a yarn plug. Irregularities in the crimp can thus be detected directly by changing structure-borne sound signals. In this case, all the signal characteristics typical for frequency analyzes can be used for monitoring.

By selecting the measuring point, the monitoring focus can be placed in the area of the thread guide or in the area of the thread rest. It is thus possible to measure structure-borne noise directly in the area of the thread channel or in the area of the stuffer box.

To generate uniform crimping qualities in the thread, the method variant is particularly advantageous, in which a measurement signal of structure-borne noise is continuously compared with at least one stored reference signal and in which a control signal for changing at least one process parameter is generated with deviation. Thus, for example, when changing the measurement signal with respect to a stored reference signal, the resulting control signal could be used to increase the delivery pressure of the delivery fluid. Likewise, this process variant can preferably be used for process adjustment at the beginning of a new process. In this case, optimized settings such as surface temperatures of godets can be found solely by constant comparison between the actual signal of structure-borne noise and the reference signal. By comparison with a stored reference signal, however, wear phenomena in the process units, such as the crimping device, can also be recognized and eliminated at an early stage.

In the case of process monitoring, it has surprisingly been found that the change in the measurement signal of structure-borne sound allows conclusions to be drawn directly about certain product properties and process settings. Therefore, the development of the invention is particularly preferably used, in which the measurement signal of structure-borne noise is continuously compared with a plurality of reference signals for identifying a process maladjustment or a product error and in which after identification of the process maladjustment or the product error, a warning signal and / or a control signal is generated. For example, the frequency spectrum of an insufficiently prepared thread showed a different characteristic than the frequency spectrum of structure-borne noise of a prepared thread. Thus, process incorrect settings or product errors can be detected and remedied quickly. The process misalignments can also indicate directly to signs of wear of the thread-guiding or thread-plug components, so that targeted exchanges of wear parts or cleaning cycles can be initiated. In particular, errors on the crimping device can also be detected immediately, such as, for example, leaks in the delivery nozzle.

However, the measurement signal of structure-borne noise is also particularly well suited to give a quality assessment of the produced crimped thread. Thus, it is proposed according to a preferred embodiment of the invention to supply the measurement signal of structure-borne noise of a statistical evaluation and at least to observe an average of the measurement signal in a threshold range. Thus, by selecting the limit value range, quality levels of the thread can be defined.

In particular, the formation of a standard deviation of the measurement signal is advantageous, so that the process uniformity and product uniformity can be monitored in a simple manner in which the standard deviation is observed with respect to a predetermined limit value.

The determination of a quality signal which can either be output directly or can be assigned to a quantity of thread produced per period of time, which has been wound, for example, into a bobbin, is particularly advantageous in the process variant in which the limit value excesses or a limit value violation are observed over a longer period of time. This can also be advantageous to generate control signals to intervene in the process.

To carry out the method, the device according to the invention has a structure-borne sound sensor, which is arranged on a housing component of the crimping device.

In this case, suitable mounting locations are both on the housing component of the delivery nozzle or the stuffer box. However, it is also possible to place a sensor directly in the wall of the thread channel of the delivery nozzle.

In order to enable the detection and evaluation of the measurement signals and the intervention in the process, the measuring device is connected to a process control device. In this case, the measuring device or the process control device has at least one data memory for storing reference signals or limit values for the structure-borne sound signal and an electronic evaluation system.

In order to convert the evaluation signals generated during the evaluation of the measurement signals into a control of the process, the process control device is connected to at least one control device associated with the ruffling device, by means of which a delivery pressure and / or a heating temperature of the delivery medium can be changed. This allows immediate intervention in the crimping process.

For visualization or documentation, the measuring device or the process control device has at least one visualization device and / or one data output unit. Thus, each wound coil can be assigned a data log, which shows the crimp quality of the wound on the coil thread.

The inventive method is described in more detail below with reference to some embodiments of the device according to the invention with reference to the accompanying figures.

They show:

Fig. 1

schematically a first embodiment of a device according to the invention for Stauchkräuseln a multifilament yarn

Fig. 2

schematically an embodiment of a crimping device

Fig. 3

schematically a scheme of structure-borne noise monitoring at the crimping device after Fig. 2

In Fig. 1 a first embodiment of the device according to the invention for carrying out the method according to the invention is shown schematically. The device according to the invention has a spinning device 1, a crimping device 9, a stretching device 24 arranged between the spinning device 1 and the crimping device 9, a take-off device 13 downstream of the crimping device 9 and a winding device 15. The spinning device 1 is connected via a melt feed 2 with a melt generator (not shown here), for example an extruder. The melt inlet 2 leads to a spinning beam 3, on whose underside a spinneret 4 is held. The spinning beam 3 is formed heated. Further provided for guiding the melt spinning pumps and distribution lines - not shown - are held in the spinning beam 3. Below the spinneret 4, a cooling shaft 6 is formed, which is combined with a blowing 7.

For spinning a group of filaments, a polymer melt is fed via the melt feed 2 in the spinning device 1. The polymer melt is extruded through the spinneret 4 held at the bottom of the spinneret 3 into a plurality of individual filaments 5. To cool the filaments 5 are passed through the cooling shaft 6, in which a generated by the blowing 7 cooling air flow is directed to the filaments 5. After cooling the filaments 5, these are combined into a bundle by a preparation device 8. The preparation device 8 is shown here schematically as a pin preparation.

After removal of the melt-spun yarn by the drafting device 24, which is formed by two godet units 24.1 and 24.2 arranged one behind the other, the multifilament yarn is fed to the crimping device 9. The crimping device is formed from a delivery nozzle 12 and a stuffer box 11 downstream of the delivery nozzle 12. The delivery nozzle 12 is connected to a fluid source, through which a tempered fluid is introduced into a thread channel of the delivery nozzle to collect the filament bundle and aufzustauchen to the subsequent stuffer box 11 to a yarn plug. At the bottom of the crimping device 9, the yarn plug 18 is guided in a subsequent cooling device 10, which is formed by a cooling drum 20. At the periphery of the cooling drum 20, the yarn plug 18 is cooled by a cooling air.

To dissolve the yarn plug 18, a crimped yarn 17 is withdrawn through the discharge device 13. The extraction device 13 is formed in this embodiment by two Abzugsgaletteneinheiten 13.1 and 13.2, between the godet units 13.1 and 13.2 a Tangeleinrichtung 14 is provided.

At the end of the process, the crimped yarn 17 is wound up into a reel 16 in the winding device 15. The winding device 15 is shown only schematically by a pressure roller 19 and the coil 16. Usually, such take-up devices have at least one traversing unit through which the thread is guided back and forth to form a spool.

For controlling the process units, a process control device 23 is provided, which is connected via a control network 25 to a plurality of control units 26.1 to 26.9 assigned to the respective process units. The respective process setting parameters of the process units are specified and controlled via the control units 26.1 to 26.9.

For monitoring the production process, the crimping device 9 is assigned a structure-borne sound sensor 21. In this case, the structure-borne sound sensor 21 is attached to a housing component of the crimping device 9. The structure-borne noise sensor 21 is coupled to a measuring device 22, which is connected directly to the process control device 23.

To operate and control the process, a combined control / visualization unit 27 is provided, which is connected to the process control device 23.

At the in Fig. 1 In the embodiment shown, a setpoint setting is initially set via the process control device 23 to each of the process units via the control units 26.1 to 26.9. During the process, one in the Component of the crimping device 9 generated structure-borne noise continuously detected by the structure-borne sound sensor 21 and the measuring device 22 abandoned. Within the measuring device 22, the measurement signal is evaluated and supplied in a converted form of the process control device 23. The signal output by the measuring device 22 is used in the process control device 23 to indicate, for example, the course of the process at the visualization unit 27. However, it is also possible to generate control signals in the event of irregularities of the measuring signal and to abandon at least one or more control units 26.1 to 26.9 for changing a setpoint specification. An embodiment for evaluating the structure-borne noise signals will be explained in more detail below.

At the in Fig. 1 illustrated embodiment of the device according to the invention for carrying out the method according to the invention, the monitoring of the structure-borne noise of a crimping device is used to allow interventions in the entire process chain. In order to be able to react as quickly as possible to process changes or product misadjustments in the process step of crimping, the method according to the invention is described with reference to an exemplary embodiment of a crimping device, as described, for example, in the exemplary embodiment Fig. 1 could be used, explain.

In Fig. 2 For this purpose, an embodiment of a crimping device 9 is shown schematically, as for example in the device according to Fig. 1 could be used. The crimping device consists of a delivery nozzle 12 and a downstream of the delivery nozzle 12 stuffer box 11. The delivery nozzle 12 includes a thread channel 28 which forms an inlet 29 at one end and an outlet 30 at the opposite end. The delivery nozzle 12 is connected via a fluid inlet 33 to a pressure source 36. The fluid inlet 33 opens into a pressure chamber 32, which is connected via a plurality of air inlet holes 31 with the thread channel 28. The air inlet holes 31 open into the thread channel 12 in such a way that a conveying medium entering through the air inlet holes 31 via the pressure chamber 32 flows into the thread channel 28 in the thread running direction.

The supply line 50 arranged at the fluid inlet 33 is associated with a heating device 34 for heating the delivery fluid and a fluid adjustment device 35 for regulating the delivery pressure and the delivery rate. The fluid control means 35 is connected via a pressure line to the pressure source 36.

The delivery nozzle 12 is arranged downstream of the discharge side immediately a stuffer box 11 having an upper portion with gas-permeable wall 39 and a lower portion with a closed chamber wall 47. In this embodiment, the gas-permeable chamber wall 39 is formed by a plurality of lamellae arranged side by side, which are arranged annularly at a small distance from one another. The lamellae of the gas-permeable chamber wall 39 are held in an upper lamella holder 38.1 and in a lower lamella holder 38.2. The gas-permeable chamber wall 39 and the holders 38.1 and 38.2 are arranged in a closed housing component 37. The annular space formed by the housing 37 outside the gas-permeable wall 39 is referred to as expansion chamber 40. The expansion chamber 40 is connected to a suction line 41. The suction line 41 is connected to a suction device 42 outside the stuffer box 11.

On the underside of the stuffer box 11, a plug outlet 51 is formed. In the short distance below the stopper outlet 51, a conveying means 48 is arranged, which is formed in this embodiment by two opposing rollers. The conveying means 48 is driven via a drive unit 49 with peripheral speed directed in the thread running direction. The control of the crimping device 9 is carried out by control device 23. For this purpose, the control device 23 is coupled by a plurality of control lines with a plurality of control devices 26.1 to 26.4. The control unit 26.1 is associated with the heating device 34 for controlling the temperature of the conveying fluid. The controller 26.2 is coupled to the fluid control means 35. The suction device 42 is controlled via the control unit 26.3 and the drive unit 49 via the control unit 26.4.

The control device 23 is connected, on the one hand, to a measuring device 22, which is coupled to a structure-borne sound sensor 21, and, on the other hand, to a data output unit 55. The structure-borne noise sensor 21 is attached directly to the wall of the thread channel 28. As a structure-borne sound sensor, for example, a piezoceramic sensor could be used.

At the in Fig. 2 illustrated embodiment of a crimping a tempered fluid is introduced with high energy in a thread channel 28 of the delivery nozzle 12, wherein the conveying fluid detected a retracted via the inlet 29 in the thread channel 28 thread 43 and promotes through the thread channel 28 to the outlet 30. In this case, the thread 43 and the conveying fluid enters the stuffer box 11 with high energy, wherein the thread 43 is deposited with its filaments on the surface of a thread stopper 18 formed in the stuffer box 11. The delivery fluid is discharged via the gas-permeable wall 39 and the expansion chamber 40 via the suction line 41 to the outside. The structure-borne noise excitation caused by the conveying fluid and the thread is detected by the structure-borne noise sensor 21 directly on the wall of the thread channel 28 and fed to the measuring device 22. Within the measuring device 22, the structure-borne sound signal is evaluated. In particular, frequency analyzes are carried out in order to analyze the frequency components that can occur in the frequency range from 50 kHz to more than 1 MHz.

In Fig. 3 For this purpose, the signal acquisition and evaluation is shown schematically. For this purpose, the measuring device 22 has a data memory 53 and an evaluation electronics 54. In the data memory 53, a reference signal f _{Ref be} deposited, which is continuously compared with the actual signal f _{actual of} the structure-borne sound sensor 21.

Alternatively, however, a plurality of reference signals may also be stored in the data memory 53, which are successively adjusted with the actual signal f _actual for example, to identify process maladjustments or product errors. As soon as an identification of a product defect or a process maladjustment has taken place, a converted signal S _{M is sent} to the control device 23 via the measuring device 22. Within the control device 23, the measurement signal S _{M can be converted} directly into a control signal S _St , for example to change the temperature of the conveying fluid or the pressure of the conveying fluid or the suction power of the expansion chamber or the conveying capacity of the conveying means. However, it is also possible to generate a warning signal when identifying before process maladjustments due to wear on the controller, so that an operator to perform component replacement or cleaning z. B. causes the delivery nozzle.

Within the control device 23, however, the measurement signal S _M can also be converted directly into a quality signal S _Q and output via a data output unit 55.

To Qualtitätsüberwachung the continuously measured sensor signal can be alternatively f _is a statistical analysis performed. In this case, all common statistical methods are possible in order to obtain meaningful characteristic values which are visualized and documented either directly via an output device or alternatively via the control device. For example, a limit value range f _G for the sensor signals can be stored in the data memory 53, wherein the actual value f _{actual is} continuously monitored. In the event that a limit value f _{G is} exceeded by the actual value F _actual , for example, the time duration of exceeding the limit value could be registered. In the event that an impermissibly long exceeding of the limit value is present, both a quality signal and a control signal could be generated.

It is also possible to form an average value signal from the current sensor signal f _Ist which is observed in a limit value range. When calculating a standard deviation, such as a CV value could the observation of only one limit value, which indicates an impermissible dispersion of the values, takes place.

At the in Fig. 2 illustrated embodiment of the crimping device, the structure-borne noise sensor 21 is arranged directly in the wall of the thread channel 28. Grundsätch it is possible to arrange the structure-borne sound sensor at any point of a housing component of the crimping device 9. Thus, for example, special characteristic of the thread plug formation signals can be determined by the structure-borne sound sensor is mounted directly on the housing 37, as in Fig. 2 is shown in dashed lines.

The method according to the invention and the device according to the invention thus make it possible to continuously monitor the quality of the crimped yarn produced and to control the entire production process of the crimped yarn in a coordinated manner, the process parameters decisive for the crimping being controlled only by monitoring a parameter. In particular, it has been found that the structure-borne sound measurement is particularly suitable for detecting disturbances in the course of the process. This makes it possible to actively intervene in the process without major time losses in order to compensate for such interference by targeted changes of process disturbances. The disturbing effects which have different effects in the frequency spectrum also facilitate the identification of the disturbance, for example due to false positives or due to product errors, so that targeted process changes can be initiated quickly and safely. A particular advantage of the method according to the invention and the device according to the invention is also based on the fact that a process parameter is detected for monitoring, which in no way influences the actual production process of the thread. The product parameters as well as the process parameters, which have a direct influence on the thread, remain untouched.

In practice, in such devices usually several threads are spun parallel parallel to each other, curled and wound. The crimping devices used in this case thus have a plurality of delivery nozzles and a plurality of compression chambers parallel to one another, which are integrated into a structural unit. In this case, a monitoring of several threads can be carried out by a structure-borne sound measurement. However, it is also possible to assign each delivery nozzle each have their own structure-borne sound sensor.

LIST OF REFERENCE NUMBERS

1

spinner

2

melt inlet

3

spinning beam

4

spinneret

5

filaments

6

cooling shaft

7

quenching

8th

preparation device

9

crimping

10

cooling device

11

stuffer

12

feed nozzle

13

off device

13.1, 13.2

Abzugsgaletteneinheit

14

entanglement

15

takeup

16

Kitchen sink

17

curled thread

18

yarn plug

19

pressure roller

20

cooling drum

21

Acoustic emission sensor

22

measuring device

23

Process control device

24

drawing device

24.1,24.2

galette

25

Control network

26.1, 26.2, 26.3

control unit

27

visualization unit

28

thread channel

29

inlet

30

outlet

31

Air inlet bore

32

pressure chamber

33

fluid inlet

34

heater

35

Fluid actuating means

36

pressure source

37

casing

38.1, 38.2

Blade support

39

gas permeable chamber wall

40

expansion chamber

41

suction

42

suction

43

thread

45

Deduction adjustment means

46

filtering device

47

closed chamber wall

48

funding

49

drive unit

50

supply line

51

plug outlet

52

pressure line

53

data storage

54

evaluation electronics

55

Data output unit

Claims (14)

1. Method for stuffing crimping a multifilament thread in which the thread is formed by a plurality of extruded filaments, in which said thread is conveyed through a thread channel to a stuffing chamber by means of a conveying fluid and stuffed in said stuffing chamber to form a yam plug, in which said yam plug is unraveled by drawing-off said crimped thread, and in which at least one process parameter is continuously recorded as a parameter for monitoring said stuffing crimping, characterized in that a structure-borne sound generated in a wall of said thread channel and/or in a wall of said stuffing chamber is measured as being said parameter.
2. Method according to claim 1, characterized in that said structure-borne sound is measured at a housing component enclosing said thread channel and/or said stuffing chamber.
3. Method according to claim 1 or 2, characterized in that a measuring signal of said structure-borne sound is continuously compared with at least one stored reference signal and in that, in the event of deviation, a control signal is generated for altering at least one process parameter.
4. Method according to one of the claims 1 to 3, characterized in that said measuring signal of said structure-borne sound is continuously compared with a plurality of reference signals for identifying a faulty process setting and in that, after identifying said faulty process setting a warning signal and/or a control signal is generated.
5. Method according to one of the claims 1 to 4, characterized in that said measuring signal of said structure-borne sound is continuously compared with a plurality of reference signals for identifying a product defect and in that, after detecting said product defect, a warning signal and/or a control signal is generated.
6. Method according to one of the claims 1 to 5, characterized in that said measuring signal of said structure-borne sound is provided to a statistical evaluation and in that at least one mean value of said measuring signal is monitored at a limit value range.
7. Method according to claim 6, characterized in that at least one standard deviation of said measuring signal is monitored in comparison to a limit value.
8. Method according to claim 6 or 7, characterized in that said limit value exceedances detected during a time period are evaluated to form a quality signal for the product quality of said crimped thread.
9. Method according to one of the claims 6 to 8, characterized in that said limit value exceedance detected in a certain time period or that said limit value exceedances detected during a certain time period is/are generated to form a control signal for altering at least one actuating variable of the process.
10. Device for performing said method according to one of the claims 1 to 9, comprising a spinning device (1), comprising a crimping device (9), comprising a draw-off device (13), and comprising a measuring device (22), where said crimping device (9) comprises a stuffing chamber (11) and a conveying nozzle (12) being formed with a thread channel (28), and where a sensor (21) connected with said measuring device (22) is associated with said crimping device (9) for recording a parameter, characterized in that said sensor is formed by a structure-borne sound sensor (21), which is disposed at a housing component (11, 12) of said crimping device (9).
11. Device according to claim 10, characterized in that said structure-borne sound sensor (21) is disposed at a wall of said conveying nozzle (12) or at a wall of said stuffing chamber (11).
12. Device according to claim 10 or 11, characterized in that said measuring device (22) is connected with a process control device (23) and in that said measuring device (22) or said process control device (23) comprises at least one data storage (53) and one evaluation electronic unit (54).
13. Device according to claim 12, characterized in that said process control device (23) is connected to at least one control device (26.1, 26.2) being associated to said crimping device (9), by means of which a supply pressure and/or a heating temperature of said conveyor medium can be altered.
14. Device according to claim 12 or 13, characterized in that said measuring device (22) or said process control device (23) is connected to a visualization device (27) and/or a data output unit (55).

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