EP1943503A1 - Procede et dispositif de détection de l'encrassement dans un ecoulement de fibres en deplacement - Google Patents

Procede et dispositif de détection de l'encrassement dans un ecoulement de fibres en deplacement

Info

Publication number
EP1943503A1
EP1943503A1 EP06804843A EP06804843A EP1943503A1 EP 1943503 A1 EP1943503 A1 EP 1943503A1 EP 06804843 A EP06804843 A EP 06804843A EP 06804843 A EP06804843 A EP 06804843A EP 1943503 A1 EP1943503 A1 EP 1943503A1
Authority
EP
European Patent Office
Prior art keywords
fiber
fiber strand
sensor
images
dirt
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP06804843A
Other languages
German (de)
English (en)
Inventor
Hans Röösli
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Maschinenfabrik Rieter AG
Original Assignee
Maschinenfabrik Rieter AG
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from DE200510053037 external-priority patent/DE102005053037A1/de
Application filed by Maschinenfabrik Rieter AG filed Critical Maschinenfabrik Rieter AG
Publication of EP1943503A1 publication Critical patent/EP1943503A1/fr
Withdrawn legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/89—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles
    • G01N21/8914—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the material examined
    • G01N21/8915—Investigating the presence of flaws or contamination in moving material, e.g. running paper or textiles characterised by the material examined non-woven textile material
    • D—TEXTILES; PAPER
    • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
    • D01G—PRELIMINARY TREATMENT OF FIBRES, e.g. FOR SPINNING
    • D01G31/00—Warning or safety devices, e.g. automatic fault detectors, stop motions
    • D01G31/003—Detection and removal of impurities
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84—Systems specially adapted for particular applications
    • G01N21/88—Investigating the presence of flaws or contamination
    • G01N21/8851—Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
    • G01N33/36—Textiles

Definitions

  • the present invention relates to a method and a device for detecting dirt in a fiber stream moving in its longitudinal direction, for example a flock stream, a fiber sliver, a roving or a yarn, in which radiation is directed against the fiber stream and radiation emitted or passed on by the fiber stream , which is obtained within the detection range of a sensor, is detected by means of this sensor, wherein detected radiation, which was influenced by fibers, differs from detected radiation, which was influenced by dirt.
  • the invention also relates to a textile machine which is provided with such a device and / or is prepared for cooperation with such a device.
  • primary light is irradiated against a fiber strand, in particular a sliver, and secondary light produced by reflections is detected by means of a line sensor oriented transversely to the direction of travel. Based on the detected secondary light, line-shaped images of a section of the fiber strand located in each case in the detection range of the line sensor can be generated one after the other and the line-shaped image can be evaluated by means of an evaluation unit for detecting dirt.
  • dirt as used herein includes the terms “contaminants”, “foreign parts” and “nits” which are described in the Handbook of Textile Fabrication, "The Short Staple Spinning Band 1: General Technology” (Author: W. Klein) See pages 13-15 and page 25, in particular.
  • the term “dirt” also includes the terms “trash” and “spurious particles” used in the following technical articles: “Trash Content of Carded and Combed Ring and Rotor Yarn” (Textiltechnik International, January / February 1994, pages 31 and 32); “New ways to achieve controlled and reproducible card sliver quality” (MeiLand Textile Reports, 7-8 / 2000, pages 587 to 592).
  • a length-specific evaluation is not possible with a device according to EP-A-643294 and also not required because the device is designed in particular for use in combination with a Gamrlick.
  • the yarn cleaner By means of the yarn cleaner, a contaminated with foreign matter piece of yarn is to be cut out immediately. It is not possible to determine the quantity of foreign substances nor their distribution in the longitudinal direction of the thread. It is also not possible to determine the size or the size distribution of the foreign substance particles.
  • dirt is detected in a fibrous structure which is in the form of a thin pile or fleece.
  • a fibrous structure which is in the form of a thin pile or fleece.
  • a nonwoven fabric Before a yarn or roving is formed, a nonwoven fabric must normally be converted into a so-called sliver. Also related to fiber. It has been suggested that it is first necessary to dissolve or spread the tape first to allow this (see, for example, GB-A-1211463). Meanwhile, it has been recognized that even without the spreading of the fibers measured values can be obtained on the sliver, see z. B ⁇ EP-A-402940 and EP-A-884408 and EP-A-1042545. However, such methods assume that the debris must appear on the surface of the belt, or that the light must penetrate the belt to detect any debris. The former assumption leads to a limited field of application for the method or the corresponding device. The second assumption leads to complex tactile devices.
  • the object of the present invention is therefore to provide a method, a device and a textile machine which avoid the disadvantages mentioned.
  • the present invention is based on a new working approach. It will first be recognized that instantaneous mapping of a current fiber stream effectively equates to a sample. Although the image can be evaluated precisely for its information content, the results apply only to the part of the stream depicted. The mapping of portions of the stream may then be repeated to obtain a complete picture over the length. But this also requires a lot of effort. If, however, it is not necessary to intervene immediately on the basis of the measured values, For example, a data series or a series of measured values obtained from individual images can be evaluated according to statistical methods in order to obtain statements with ascertainable confidence limits.
  • a test room on the current fiber stream in particular on a sliver, are to be defined, without influencing the fibers themselves.
  • the current content of the rehearsal room is examined and corresponding signals are generated, which can be evaluated.
  • the examination is repeated at predetermined intervals to produce a series of sample values.
  • This series of evaluations can itself be evaluated in order to allow statistically significant statements regarding the total fiber flow.
  • the method is capable of producing quality metrics that can be used operationally to reliably control machinery or fiber processing steps.
  • the method preferably operates by optical means, ie the sample space is defined by directing light or light-like radiation against the surface of the sliver and radiation returned or passed on from the current content of the sample room is detected and evaluated.
  • the volume or the size of the sample room is determined by the brightness of the radiation source, the sensitivity of the detection means (sensor) and the optics.
  • the sample compartment preferably comprises a three-dimensional flow part which includes a part of the flow surface. However, this current part preferably comprises only relatively few fiber layers in the vicinity of the abovementioned surface part, so that the fiber flow is by no means penetratingly examined.
  • the fiber stream is preferably guided past the sensor in such a way that the sample space is always filled uniformly with fibers.
  • Each picture can be cell shaped. Cell-shaped images can then be strung together in the evaluation to give a two-dimensional image of a stream section.
  • a sensor in the form of a camera it is possible to directly produce a two-dimensional image, i. H. without having to produce this image by composing a plurality of line-shaped mappings. But even a two-dimensional image represents only one evaluable sample compared to the length of a fiber stream.
  • a predetermined clock frequency for the creation of the images can be defined.
  • the method according to the invention can then be further characterized in that the speed of a fiber strand is continuously recorded and taken into account in the specification of the clock frequency and / or in the evaluation of the images.
  • the speed of the fiber strand in the evaluation of the images is an exact statistical statement about the amount and distribution of dirt in the longitudinal course of the fiber strand possible.
  • the size or the size distribution of the dirt particles can be determined.
  • the consideration of the speed of the fiber strand in the specification of the clock frequency of an optimized number of images generated per length of content of the fiber strand Since neither too little nor too many line-shaped images per longitudinal section are produced even if the speed of the fiber strand changes, reliable evaluation results result with justifiable evaluation effort.
  • the method is suitable for detecting dirt in a yarn, a roving or an open guided or in a compressed example by means of a funnel sliver.
  • Dirt is the totality of unwanted particles in the fiber strand whose particle size - as a delimitation criterion to dust - is greater than 0.5 mm. Dirt occurs especially in the use of natural fibers, such as cotton, and includes mainly earth, shell parts and nits.
  • the method is suitable for detecting foreign material, which has got into the fiber material, for example, during transport of the raw fibers.
  • the clock frequency is set so that the imaged sections of the fiber strand adjoin each other in the longitudinal direction seamlessly. This results in the entirety of the images produced a gap-free, true-to-scale image of the fiber strand. This leads to a high statistical reliability of the evaluation results, whereby the effort for evaluation is limited.
  • the clock frequency is set so that overlap the imaged sections of the fiber strand in the longitudinal direction. This results in an at least partial redundancy of the images, which leads to an increase in the measurement accuracy. This arrangement is particularly advantageous when non-pulsed illumination is used.
  • Line-shaped images can be generated with a constant clock frequency, ie isochronously.
  • EL is dependent on the width of the photosensitive area of the line sensor and a possibly used lens.
  • the clock frequency is specified as a variable, the value of which is determined continuously as a function of the extent of the detection range of the line sensor in the longitudinal direction and the actual speed of the fiber strand so that a constant number of line-shaped images is generated per unit length of the fiber strand.
  • the clock frequency can be set so that overlap the imaged sections of the fiber strand in the longitudinal direction (LR) with a constant degree of coverage, this can be supplemented by a constant multiplier formula.
  • a plurality of successively generated line-shaped imaging fertilizers are combined to form a two-dimensional image, which is then evaluated for detecting dirt.
  • the extent of dirt particles in the longitudinal and transverse directions can be determined exactly.
  • pattern recognition is particularly preferably carried out, wherein shape, area, position, brightness values, brightness distributions, color values, color distributions and / or the sharpness of the edges of patterns occurring are used to detect dirt. In this case, a reliable qualitative and quantitative detection of dirt is possible.
  • detected dirt particles are classified into predefined classes on the basis of their properties, such as, for example, their shape, area or color.
  • the predefined classes can be evaluated statistically. Thus, for example, the prevailing size of the dirt particles or the frequency of occurrence of nits can be determined.
  • pulsed primary light is radiated against the fiber strand, the pulses being synchronized with the generation of the line-shaped images.
  • the pulses being synchronized with the generation of the line-shaped images.
  • the intensity of the primary light is adapted continuously and automatically to the reflection properties of the fiber strand determined by the evaluation unit. This ensures that the line sensor is operated in an optimal range of its characteristic. This causes a high-contrast imaging of the fiber strand.
  • the inventive device is designed in particular for carrying out the method described above.
  • it can use a wired or wireless reception interface to receive the measurement signals of the actual Having speed of the fiber strand measuring speed sensor, wherein the receiving interface for forwarding the measurement signals to the clock generator to the clock generator and / or for forwarding the measurement signals to the evaluation unit is connected to the evaluation unit.
  • the receiving interface may be a simple wire connection, a GSM interface, a Bluetooth interface, a Can-Link interface or a USB interface.
  • the reception interface makes it possible to connect the device according to the invention to a speed sensor which is present anyway on many textile machines.
  • the clock generator is designed so that on the basis of the measurement signals forwarded to it an automatic determination of a said clock frequency takes place continuously, in which the fiber strand is imaged gap-free in its longitudinal direction.
  • a gap-free mapping can be ensured by the continuous adaptation of the clock frequency at any speed of the fiber strand.
  • the clock generator can be designed so that a continuous and automatic determination of a said clock frequency is performed such that the imaged sections of the fiber strand in the longitudinal direction have a constant, independent of the actual speed coverage.
  • the clock generator can be designed such that an automatic determination of a said clock frequency takes place in such a way that the imaged sections of the fiber strand adjoin one another seamlessly in the longitudinal direction.
  • the evaluation unit is designed to join a plurality of successively generated cell-shaped images into a two-dimensional image and to evaluate the two-dimensional image so as to detect dirt. If the evaluation unit is designed to take into account the actual speed of the fiber strand during the assembly of a plurality of successively generated line-shaped images, a constant clock frequency can be predetermined.
  • the evaluation unit is designed for pattern recognition in the evaluation of the two-dimensional image, whereby the shape, area, position, brightness values, brightness distributions, color values, color distributions and / or the sharpness of the edges of occurring patterns for detecting dirt can be used.
  • the evaluation unit is designed for the classification of detected dirt particles on the basis of their properties in predefined classes.
  • the evaluation unit can be designed to evaluate the distribution of the dirt particles to the individual classes.
  • the evaluation unit comprises a microprocessor and preferably a memory module. In this way, the desired functions can be easily realized.
  • a lighting control module which controls the lighting arrangement such that pulsed primary light is radiated against the fiber strand, wherein the pulses are synchronized with the generation of the cell-shaped images.
  • the lighting control module for the current and automatic adjustment of the strength of the primary light to the determined by the evaluation unit reflection properties of the fiber strand is formed.
  • a closed loop may be formed, which comprises the line sensor, the evaluation unit, the lighting control module and the lighting arrangement.
  • the illumination control module is assigned a D / A converter for receiving digital control and / or regulating signals for controlling and / or regulating the illumination arrangement.
  • the illumination arrangement comprises one or more light-emitting diodes.
  • Light-emitting diodes are particularly suitable for illuminating the fiber strand, since they require comparatively little energy, have a defined color and, when switched on or off, change the light output with an extremely small time delay.
  • the line sensor comprises a plurality of photodiodes arranged in a row.
  • Such line sensors are inexpensive to manufacture, durable and work with high accuracy.
  • each photodiode can be assigned a charge store and / or an amplifier circuit.
  • the lens sensor can be preceded by a lens.
  • the lens has a diaphragm, which is preferably adjustable. As a result, sharper images can be generated and the amount of light incident on the line sensor can be regulated.
  • the line sensor is associated with an A / D converter for converting the sensor signals.
  • the sensor signals can be further processed directly digitally.
  • the device has a display unit, in particular a display, for displaying evaluation results and / or operating states of the device.
  • Displayable evaluation results can be, for example, the quantity or the quality of the detected dirt.
  • As an operating state can be displayed, for example, whether the device is on or off.
  • a wireless or wired interface in particular a GSM interface, a Bluetooth interface, a Can-Link interface, a USB interface or an interface according to another industry standard, for the transmission of outgoing data, in particular generated zeiienförmige mappings, generated two-dimensional images, operating states of the device, fault messages, evaluation results and / or control commands provided.
  • This makes it possible to store or further process the images or images produced.
  • Control commands can be transmitted, for example, to a machine or system control. So it is possible to automatically shut down a textile machine or a system when a predetermined amount of dirt occurring is exceeded.
  • the interface for the transmission of incoming data in particular software, software updates and / or parameters for the evaluation, such as threshold values, be formed. Also, a remote control of the device is conceivable.
  • the device has a substantially closed housing, wherein a window for exiting the Primärfichts and for the entry of the secondary light is provided. Openings in the housing are limited to a minimum, for example for the passage of cables. In this case, the device can also be used in harsh environmental conditions.
  • the window is made of a transparent material, so that the primary light and the secondary light can pass undisturbed.
  • a sapphire crystal Al 2 O 3
  • a guide device for guiding the fiber strand. This ensures that the fiber strand is correctly positioned with respect to the line sensor.
  • the guide device is preferably configured in a U-shaped cross-section. det, wherein the window is formed on the inside of the base of the U's. This results in a simple, compact and resistant design.
  • the guide means for guiding the fiber strand is preferably formed so that the fiber strand is guided on all sides.
  • the guide device may be formed, for example, as a through hole on the housing of the device.
  • the guide device is designed so that the fiber strand can be brought into the guide device transversely to its longitudinal direction. Then it can be dispensed with a cutting of the fiber strand, if this is to be threaded.
  • the device is designed as a self-sufficient module, which can be fastened to a textile machine by means of a detachable mechanical connection, for example with a clamping connection, a plug connection, a magnetic connection and / or a latching connection.
  • the device can preferably be mounted or removed without tools on the textile machine. Autarkic means that the device is self-sufficient. This makes it possible to use the device alternately on different textile machines.
  • the electrical connection means may comprise contacts arranged on the module and corresponding contacts arranged on the textile machine. These can be designed so that the contacts come into contact automatically when the device is attached to the textile machine.
  • a textile machine according to the invention has a device according to the invention for detecting dirt or is prepared for fastening a self-sufficient module.
  • Figure 1 shows an inventive device which is designed as a self-sufficient module
  • FIG. 2 is a block diagram of a device according to the invention.
  • FIG. 3 shows a further exemplary embodiment of a block diagram of a device according to the invention.
  • FIGS. 5a, 5b and 5c show the generation of a two-dimensional image according to a modified method
  • Figure 6 is a copy of Figure 2 of EP-A-446808.
  • Figure 7 is a copy of Figure 3a of EP-A-446808;
  • Figure 8 is a copy of Figure 3b of EP-A-446808;
  • Figure 9 is an isometric view of one embodiment of the present invention.
  • Figure 10 is a schematic diagram for explaining the operation of the embodiment according to Figure 9;
  • FIG. 11 is a timing chart for explaining the evaluation of signals in an embodiment according to FIGS. 9 and 10;
  • FIG. 12 is a schematic diagram for explaining a modified embodiment
  • FIG. 13 shows a diagram for the representation of a determined background curve for the individual photodiodes of a line sensor
  • FIG. 1 shows a device according to the invention which is designed as a self-sufficient module 1. is forming. It has a closed housing 2, in which a lighting arrangement 3 is arranged with a light emitting diode 4 for generating primary light PL.
  • the primary light PL penetrates out of the housing 2 through a transparent window 5, whereby secondary light SL arises from reflections on the fiber strand FS, at least part of which passes back into the housing 2 through the window 5.
  • the secondary light SL passes through an objective 6 and through an aperture 7 on the photosensitive side of the line sensor 8.
  • a multiplicity of photodiodes 9 are arranged, which convert appropriate secondary light SL into electrical signals SE.
  • the electrical signals SE represent line-shaped images of a section of the fiber strand FS located in each case in the detection range of the line sensor 8.
  • the line sensor 8 is mounted at a distance E to the lens 6 within the housing 2.
  • z. B. a test pattern pattern presented to the window 5
  • the module 1 can be focused by changing the distance E in the production to obtain a picture with the best possible, or maximum contrast.
  • a representative value for each photodiode 9 can be determined and stored in the evaluation unit. By using these values in the evaluation during operation, the existing tolerances and sensitivities between the individual photodiodes are taken into account. That is, it is - seen over the width of the line sensor 8 - created a representative background curve for the photodiode 9. This background curve then forms the basis for the evaluation of the reflected secondary light SL.
  • These signals SE or the line-shaped images are fed to an evaluation unit 10 for the purpose of evaluation.
  • Evaluation results are sent to a display 11 and can be displayed there. Furthermore, the evaluation results can be sent to an interface 12 and from there to an external computer, for example for long-term analysis. time storage or for long-term evaluation.
  • the generation of the line-shaped images by the line sensor 8 is carried out with a clock frequency TF 1 which is predetermined by a clock generator 13.
  • the clock frequency TF is also transmitted to a lighting control module 14. This supplies the lighting arrangement 3 with energy in such a way that the light-emitting diodes 4 emit pulsed primary light PL with a defined power.
  • the illumination control module 14 also receives from the evaluation unit 10 a signal HS for brightness control.
  • the clock generator 13 evaluates the measurement signals MS of a sensor 27, which detects the speed of the fiber strand FS.
  • the sensor 27 is part of a textile machine 100 to which the module 1 is fastened by means of releasable mechanical connection means 16.
  • the detachable mechanical connection means 16 consist of elements 16a, which are arranged on the module 1, and of elements 16b, which are arranged on the textile machine 100.
  • the elements 16a and 16b are designed to interact. They may for example be designed as permanent magnets.
  • the measurement signals MS of the sensor 27 are received by a receiving interface 15 of the module 1 via a wired connection.
  • releasable electrical connection means 17 are integrated, comprising arranged on the module 1 contacts 17a and arranged on the textile machine 100 contacts 17b.
  • the contacts 17a and 17b are formed and arranged so that the connection of the sensor 27 to the receiving interface 15 is automatically established when the module 1 is attached to the textile machine 100.
  • the connection could be made via a manually attachable cable.
  • the received measurement signals MS are transmitted to the clock generator 13 so that it can determine and preset the clock frequency TF as a function of the speed of the fiber strand FS.
  • the measurement signals MS are transmitted to the evaluation unit 10, so that the speed of the fiber strand FS can also be taken into account in the evaluation of the line-shaped images.
  • a guide device 20 for guiding the fiber strand FS is formed on the housing 2, which has a U-shaped cross-section, wherein the window 5 is arranged at the base of the U and the fiber strand FS is guided by the legs of the U and its base.
  • the fiber strand FS can be laterally switched on or swung over the open side of the U's.
  • the width B of the fiber strand FS is determined by the distance between the legs of the U and independent of the cross section of the fiber strand FS.
  • the detection width of the line sensor 8 is determined by the width of the window 5, the lens 6 and the length of the photosensitive region of the sensor 8 and - regardless of the thickness of the fiber strand FS - less than its width B. Therefore, a change in the cross section of the fiber strand FS does not affect the images produced or the evaluation thereof.
  • a power supply 18 is provided in the housing 2, which comprises a self-sufficient energy source, namely a battery pack 19.
  • the power can be supplied from the textile machine 100.
  • FIG. 2 shows a detailed block diagram of a device according to the invention.
  • the line sensor 8 has a multiplicity of photodiodes 9, of which eight are shown by way of example. Usually, at least 32, preferably at least 64 and more preferably 128 photodiodes 9 are provided. Each photodiode 9 is associated with a charge storage 21 and an amplifier circuit 22.
  • the analog signal SE 'of the line sensor 8 is fed to an A / D converter 23 and converted by the latter into a digital signal SE.
  • the digital signal SE is fed to the evaluation unit 10, which has a microprocessor 24 and a memory module 25 connected thereto.
  • the microprocessor 24 determines from the digital signal SE a target value for the brightness of the primary light PL.
  • This setpoint is contained in the digital signal HS, which is transmitted from the microprocessor 24 to a D / A converter 26 and from there as an analog signal HS 'to a lighting control module 14.
  • the lighting control mode dul 14 in turn regulates the light output of the LEDs 4 of the lighting device 3 based on the signal HS '. For this purpose, it has a suitable power electronics.
  • the measurement signals MS of the speed sensor are passed through the receiving interface 15 to the microprocessor 24 and to the clock generator 13.
  • the clock generator 13 generates a clock frequency TF, which for the timing of the Zeiiensensors ⁇ , the A / D converter 23, the lighting control module 14 and. of the D / A converter 26 is forwarded.
  • the brightness of the LEDs 4 is determined by the evaluation unit 10 and the pulsation of the LEDs by the clock generator 13.
  • both parameters could be specified by the evaluation unit 10. In this case, it is not absolutely necessary to transmit the clock frequency TF of the clock generator 13 to the lighting control module 11.
  • the microprocessor 24 is still in communication with the interface 12 and the display 11th
  • the signal of the photodiodes may be amplified via an amplifier circuit 22.
  • FIG. 3 shows a modified block diagram of a device according to the invention.
  • the function of the clock generator 13 is in this case integrated into the microprocessor 24.
  • the functions of the receiving interface 15 for receiving the measuring signals MS of the speed sensor and the interface 12 for receiving incoming data and for sending outgoing data are combined in one unit.
  • FIG. 4a shows a fiber strand FS which is moved in its longitudinal direction LR at the speed G relative to a line sensor.
  • the fiber strand FS has a dirt particle S.
  • the detection range of the line sensor is by its longitudinal extent EL and described by its transverse extension EQ.
  • Each line-shaped image generated by the line sensor therefore represents a section A of the fiber strand FS 1 , each section A being the same length and the same width.
  • the width of the sections A corresponds to the transverse extent EQ of the detection range of the line sensor.
  • the generation of a line-shaped image takes place with a sufficiently short exposure time, then the longitudinal extension of the sections A corresponds to the longitudinal extent EL of the detection range of the line sensor.
  • the longitudinal extent of the sections A can then be regarded as independent of the speed G of the fiber strand FS.
  • line-shaped images of the fiber strand FS are generated in succession, the underlying cycle frequency being selected such that the imaged sections A1 to A6 adjoin one another without gaps.
  • the speed G of the fiber strand FS it is not necessary for the speed G of the fiber strand FS to remain constant, since the clock frequency is specified taking account of the speed G.
  • FIG. 4b shows the line-shaped images Z1 to Z6, which each represent one of the sections A1 to A6.
  • Each line-shaped image Z1 to Z6 comprises a plurality of linearly arranged pixels BP.
  • a brightness and / or color value is determined and recorded.
  • the cell-shaped images Z1 to Z6 are transmitted to the evaluation unit and evaluated there. For this purpose, these are combined to form a two-dimensional image ZDB shown in FIG. 4c. Since the imaged sections A1 to A6 each adjoin one another without gaps, the image ZDB can be generated in a simple manner by juxtaposing the line-shaped images Z1 to Z6.
  • the image ZDB is a true-to-scale image of the detected section of the fiber strand FS.
  • the two-dimensional image ZDB can now be evaluated by means of pattern recognition. In particular, a length-related evaluation is possible.
  • Figures 5a, 5b and 5c show a modification of the method, wherein the clock frequency as a function of the speed G of the fiber strand FS so determined is that each adjacent sections, which are represented by cellular images overlap with a constant degree of coverage in the amount of 50%.
  • line-shaped images Z1 to 2 12 are now formed when imaging the same longitudinal section of the fiber strand FS 12.
  • the overlapping images Z1 to Z12 detect each region of the fiber strand FS twice. As a result, accidental measurement errors can be at least reduced in their effect.
  • the line-shaped mappings Z1 to Z12 can not simply be lined up in the generation of the two-dimensional image ZDB ', since in this case a distortion would result.
  • the detection range of the line sensor and the speed G of the fiber strand FS is known. Therefore, a true-to-scale image ZDB ', which is shown in Figure 5c, can be used. are calculated from the line-shaped maps Z1 to Z12.
  • the two-dimensional image ZDB ' has six lines and can be evaluated in the usual way, whereby a length-specific evaluation is readily possible.
  • the pixels have different brightness values for the region of the detected dirt particle.
  • the edge regions of the dirt particle which are partly below the surface of the fiber stream, have a higher brightness value than the center of the dirt particle protruding from the fiber strand.
  • These differences can z. B. be used to carry out the statistical evaluation. That is to say, as soon as it is determined on the basis of the detected brightness value that it is a dirt particle projecting from the fiber mass, the pixels with a higher brightness value detected around the center of the detected dirt particle are also detected in order to detect the size of the dirt particle which is responsible for a statistical evaluation of the dirt particle is used.
  • FIG. 6 shows the discharge section 120 of a carding machine (a machine without a fiber ribbon) and the band depositing station 121 downstream of this outlet with a can 121 'for receiving the sliver in turns.
  • a measuring point with a measuring probe 101 is provided on the tape tray 121.
  • the measuring probe 101 according to the EP document is suitable for obtaining color measurement values on the passing fiber sliver FS (see FIG. 7).
  • the measuring probe is arranged at a point where "process-inherent compression" takes place, where the sliver passes through a funnel 122.
  • the funnel neck 123 (FIG In order for the continuous sliver FS to have a width sufficient for color measurement, the funnel neck 123 has the shape of a very flat rectangle with rounded corners as shown in Figure 8.
  • the wide side 124 of the funnel neck 123 facing the probe consists of a translucent material, the opposite side 125 carries against the sliver turned a replaceable surface in the appropriate background color on the storage hopper follows in the direction of tape travel, a pair of transport rollers 126th
  • the measuring point is not provided on the tape storage, but directly after the card discharge, for example at the point X (FIG. 6), after completion of the band formation.
  • a suitable embodiment of the measuring device is shown in FIG.
  • FIG. 9 shows a housing 2 with a front wall 50 and walls 2OA, 2OB protruding therefrom.
  • the wall 50 forms a curved guide surface for a sliver, z. B. for the band FS (Fig. 7).
  • a translucent window 5 is provided and the housing 2 includes one for the realization of the invention suitable electronics and optics (not visible in FIG. 9, a suitable arrangement has been described in connection with FIG. 1).
  • the conditions at the window 5 will now be explained in greater detail, with reference to the schematic diagram in FIG. 10, where the guide surfaces formed by the walls 20A, 20B and the window 5 are shown schematically.
  • FIG. 1 shows the level of the output signal from unit E over time.
  • the secondary radiation generated by the fibers excited in the unit E although variable, but always relatively high signal level P.
  • a Trashp such as the particle T1
  • the particle T1 which appears on the belt surface at the window 5 or in the vicinity of this surface, falls Signal level strong as long as the particle T1 effectively shields the fibers in the band of the primary radiation, because the particle T1 generates significantly less secondary radiation, as the fibers.
  • the sensitivity of the unit E is chosen such that fibers in even deeper layers, further away from the window 5, can exert no discernible effect on the signal level P.
  • the system is thus tuned such that the unit E is unable to detect secondary radiation from parts of the sliver further away from the window 5, then not; when the primary radiation can penetrate into these deeper layers. Therefore, a trash particle, such as the particle T3 trapped in these deeper fiber layers, can not exert a noticeable effect on the signal level P.
  • the particle T3 even possibly exerts a certain effect on the detected secondary radiation, which at most leads to a decrease in the signal level P.
  • this change in the output of unit E falls within the "bandwidth" (tolerance), which is also affected by other factors in the system, so that the effects of these various factors can not be reliably differentiated.
  • the "light collecting space" of the unit E thus extends only to a depth t from the front wall 50 (from the window 5) and by no means comprises the entire thickness of the sliver, which is not even completely shown in the sketch according to FIG
  • the depth t can be kept small, for example in the range of 0.1 to 0.5 mm.
  • the function of the tape guiding device, which consists of the surface 50 and the side walls 20A, 20B, is therefore to provide for this in that, for a given belt tension, the space which can be allocated to the light collecting space of the unit E is always and as evenly as possible filled with fibers of the moving belt.
  • compression of the belt for this purpose is not required; kung, for example by means of a slight curvature of the surface 50, but quite appropriate.
  • the amount of material which exerts a momentary influence on the signal level P is determined not only by the distance t from the window 5, but also by the size of the two-dimensional detection range of the sensor, namely its extension both in the direction of movement of the sliver and in the direction perpendicular to it.
  • the detection range is determined in the transverse direction by the width W of the window 5, and the width W is considerably smaller than the distance S between see the guide surfaces 2OA, 2OB.
  • the size of the detection area is determined by the design of the unit E rather than by the design of the window 5.
  • the current content (fibers, particles, etc.) of this rehearsal room can be considered as a "sample", which is to be examined by means of the unit E.
  • the sample is, for example, less than 5% of the fiber material (from the longitudinal section of the fiber sliver), which in the moment of the unit E is opposite.
  • spurious particles in elongated textile products such as tapes, rovings and yarns are well known to those skilled in the textile laboratory (offline) and need not be repeated here.
  • a determined number of interfering particles is directly or indirectly in This amount of fiber can be determined in units of weight (eg per g) or in units of length of the product being examined (eg per m or km).
  • the spurious particles themselves can be assigned to various types, for example, nits, shawls, trash particles, dust, and the particles can be assigned to different classes depending on their sizes within these types. Examples of the practical application of these principles are, for.
  • measured value series can be further investigated according to the statistical method, for example by determining the frequency distribution with corresponding derivations with respect to characteristic characteristics of this distribution.
  • a normal (Gaussian) distribution frequency distribution in the form of a bell-shaped curve
  • z the mean value of the distribution can be readily determined and taken as a characteristic characteristic of the distribution.
  • the result of the evaluation should be specifically reported or an alarm triggered and / or the fiber processing to be stopped.
  • the display can be designed in such a way that both the valid characteristic values and the parameters for the trustworthiness of these values are displayed.
  • the invention therefore provides a kind of automated sample analysis.
  • the sample may include all the fibers that are in front of the sensor at the time of making an image, i. H. it may comprise all fibers which are located in a predeterminable longitudinal section of the fiber stream.
  • This mode of operation is possible where the radiation is able to "shine through” the fiber stream and the sensor is able to react on the entire contents of the longitudinal section, but this operation is relatively expensive and not required to be reliable To achieve results.
  • the sample may therefore comprise only a portion of the fibers located in a longitudinal section of the fiber stream.
  • This portion of the fibers may comprise only those fibers which are located on the surface or on a part of the surface of a fiber structure, for example in the detection of foreign fibers in a compact structure such as a roving or a yarn.
  • this part of the fibers comprises both those fibers which are in the detection range of the sensor at the surface of the fiber strand also fibers within this surface.
  • the now proposed method of operation can be used in all stages of processing of fibers in the spinning line, ie also in series of measurements, which were obtained from a flock stream or were obtained from a roving or a yarn.
  • the now proposed method of working is not useful if immediately on the detection of interfering particles or foreign material should be reacted, z. B. in the yarn cleaning.
  • the statistical analysis of the sample analysis can not provide instantaneous values that can be used as a reliable basis for immediate control intervention.
  • the new method is especially useful where the fiber stream to be examined has a relatively high content of interfering particles, eg. B. after the card until the formation of a coil in the Kämmereivorkung.
  • the sample analysis is also particularly useful if the content of the samples can be accepted as representative of the total content of the fiber stream. Where z. If, for example, systematic effects lead to differences between the content of interfering particles in the "rehearsal room" and other parts of the flow, either these effects must be taken into account in the evaluation or the reliability of the results must be reduced.
  • the instantaneous velocity of the fiber stream is important for various aspects of a complete evaluation - examples: for (a) the assignment of the determined spurious particles to respective fiber stream parts (b) the determination of the actual size of a particular particle (c) the compilation of the images to create an image the passing fiber stream or predetermined longitudinal sections thereof.
  • the use of a signal provided by the machine in this regard is a useful but not optimal compromise. It would be better to determine the instantaneous running speed of the fiber flow within the test apparatus itself.
  • the principles of a suitable solution will be explained for the time being with reference to a schematic representation in FIG.
  • the embodiment according to FIG. 12 like the embodiment according to FIG. 9, comprises a housing 2 with a curved front wall 50 and sliver guide walls 20A, 20B (only wall 2OA visible in FIG. 12).
  • the housing 2 has in FIG. 12 two chambers 52 and 54, each with a window 5A, 5B in the front wall 50 and one sensor unit E1 and E2 respectively.
  • the running direction of the sliver is indicated by the arrow L.
  • the two units E1, E2 each define a detection area and these areas have a known, mutual distance A in the direction of L on. This distance may be between planes perpendicular to the respective detection. be defined, provided that the selected levels each have the same relationship to the respective coverage area, for example, in each case the median plane of the area.
  • the unit E1 therefore first creates a map ABB1 of a certain sliver section at a time Z1, where this section is located in the detection area of the unit E1. Shortly thereafter, at time Z2, unit E2 creates a map ABB2 of the same sliver section as this section is within the coverage of that unit.
  • Each unit E1, E2 delivers its respective map ABB1, ABB2 to a signal processor P, which is provided with a timing device Z or cooperates, so that the time Z1 or Z2 of the creation of the respective image is fixed.
  • the processor is able to recognize that they are from the same sliver section.
  • the time interval between the presence of this portion in the detection range of the unit E1 and the presence of the portion in the detection range of the unit E2 can therefore be determined, wherein the instantaneous speed of the sliver in the device 2 can be derived from the known distance A.
  • the invention therefore provides, in all variants, a method for detecting dirt in a fiber stream moving in its longitudinal direction, in particular a sliver, in which radiation is directed against the fiber stream and radiation emitted or passed on by the fiber stream, which is obtained within the detection range of a sensor , is detected by this sensor, wherein detected radiation, which was influenced by fibers, differs from detected radiation, which was influenced by dirt.
  • a method for detecting dirt in a fiber stream moving in its longitudinal direction, in particular a sliver in which radiation is directed against the fiber stream and radiation emitted or passed on by the fiber stream, which is obtained within the detection range of a sensor , is detected by this sensor, wherein detected radiation, which was influenced by fibers, differs from detected radiation, which was influenced by dirt.
  • at least one image of a fiber stream portion may be generated and evaluated by an evaluation unit to determine whether differences in the detected radiation within the image suggest the presence of debris within the fiber stream portion.
  • a second detection area is defined as viewed in the direction of movement of the fiber stream, whereby radiation occurring within the second detection area is also detected and used to form a respective image.
  • An evaluation unit can be provided which compares images which originate from the respective detection areas with one another in order to detect similarities and thus to associate the respective images with the same fiber flow section. If the said detection areas have a previously known respective distance in the direction of movement of the fiber stream, the current velocity of the stream can be inferred when recognizing similarities in two images which were ever created at a known time. This information can then be used to further analyze the data, for example, to compile the images of a series to form a larger image.

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  • Engineering & Computer Science (AREA)
  • Textile Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Medicinal Chemistry (AREA)
  • Food Science & Technology (AREA)
  • Computer Vision & Pattern Recognition (AREA)
  • Signal Processing (AREA)
  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
  • Treatment Of Fiber Materials (AREA)

Abstract

L'invention propose un procédé de détection de l'encrassement (S) dans un écheveau de fibres (FS) déplacé dans le sens de sa longueur (LR), par exemple un ruban de fibres, un pré-fil ou un fil. Une lumière primaire (PL) est émise en direction de l'écheveau de fibres (FS) et la lumière secondaire (SL) qui résulte des réflexions est détectée au moyen d'un détecteur linéaire (8) aligné transversalement par rapport à la direction d'avancement. A partir de la lumière secondaire (SL) détectée à une cadence prédéterminée (TF), des images linéaires (Z1, ..., Z12) successives de la partie (A1, ..., A12) de l'écheveau de fibres (FS) située à chaque fois dans la plage de détection du détecteur linéaire (8) sont créées et les images linéaires (Z1, ..., Z12) sont évaluées au moyen d'une unité d'évaluation (10) pour y détecter l'encrassement (S). Le procédé est caractérisé en ce que la vitesse (G) de l'écheveau de fibres (FS) est détectée en permanence et est prise en compte lors de la détermination de la cadence (TF) et/ou lors de l'évaluation des images linéaires (Z1, ... Z12). L'invention concerne également un dispositif correspondant.
EP06804843A 2005-11-04 2006-10-31 Procede et dispositif de détection de l'encrassement dans un ecoulement de fibres en deplacement Withdrawn EP1943503A1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE200510053037 DE102005053037A1 (de) 2005-11-04 2005-11-04 Verfahren zur Erfassung von Schmutz in einem bewegten Faserstrang
CH18852005 2005-11-28
PCT/CH2006/000609 WO2007051335A1 (fr) 2005-11-04 2006-10-31 Procede et dispositif de détection de l'encrassement dans un ecoulement de fibres en deplacement

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EP1943503A1 true EP1943503A1 (fr) 2008-07-16

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DE102006057215B4 (de) * 2006-12-01 2022-08-11 Trützschler GmbH & Co Kommanditgesellschaft Vorrichtung an einer Spinnereivorbereitungsanlage zum Erkennen von Fremdstoffen in Fasergut
WO2012085632A1 (fr) * 2010-12-23 2012-06-28 Pirelli Tyre S.P.A. Procédé et appareil de régulation de la production et de l'avance de produits semi-finis dans un processus de construction de pneus
WO2015092659A1 (fr) * 2013-12-16 2015-06-25 Pirelli Tyre S.P.A. Procédé et appareil pour contrôler la fabrication et l'introduction de produits semi-finis dans un processus d'élaboration de pneu

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GB2095828B (en) * 1981-03-31 1985-12-18 Wool Dev Int Detection of defects in fibrous arrays
CH669401A5 (fr) * 1988-03-02 1989-03-15 Loepfe Ag Geb
DE3928279C2 (de) * 1989-08-26 1998-05-14 Truetzschler Gmbh & Co Kg Verfahren und Vorrichtung zum Erkennen von störenden Partikeln, insbesondere Trashteilen, Nissen, Schalennissen, Noppen u. dgl., in textilem Fasergut, z. B. Baumwolle, Chemiefasern u. dgl.
US5394480A (en) * 1991-09-19 1995-02-28 Zellweger Uster, Inc. Topological map maker
US6052182A (en) * 1997-10-28 2000-04-18 Zellweger Uster, Inc. Fiber quality monitor

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