GB2354011A

GB2354011A - Apparatus for forming a card web of textile fibres

Info

Publication number: GB2354011A
Application number: GB0021871A
Authority: GB
Inventors: Fritz Hoesel
Original assignee: Truetzschler GmbH and Co KG
Current assignee: Truetzschler GmbH and Co KG
Priority date: 1999-09-09
Filing date: 2000-09-06
Publication date: 2001-03-14
Anticipated expiration: 2020-09-06
Also published as: IT1318821B1; ITMI20001954A1; GB0021871D0; GB2354011B; ITMI20001954A0; JP2001123338A; FR2798398A1; DE19943079A1; FR2798398B1; CH694507A5

Abstract

In a carding machine in which a card web 16 of textile fibres is formed, the card web 16 comprising areas of good fibres and intervening areas, a measuring region for the fibre material is provided, which has associated with it a camera 18, for example, a diode matrix camera, which is connected to an electronic evaluating device 23. To permit recording and assessment of the homogeneity of the card web 16, especially the distribution and orientation of the good fibres, and to improve the degree of evenness of the web, the areas of good fibres and intervening areas are recordable by the camera 18, the measured values are arranged to be converted into electrical signals and supplied to the evaluating device 23, and the apparatus is capable of determining the distribution of the good fibres in the card web per unit of area.

Description

2354011 Apparatus for formincr a card web of textile fibres The invention

relates to an apparatus on a carding machine or similar machine, in which a card web of -textile fibres, for example, cotton, man-made fibres or similar fibres, is formed, the card web comprising good fibres and empty spaces. Such an apparatus may have a measuring section for the fibre material, which has associated with it a camera, for example, a diode matrix camera, which is connected to an electronic evaluating device (image-processing computer).

In a known apparatus (DE-OS 39 28 279), unwanted particles are identified in order to determine the degree of contamination (trash content) of the fibre material opto-electronically. To that end, a sensor detects each unwanted individual particle in the moving card web, for which the evaluating device determines specific parameters for each individual particle, especially greyscale detections and edge detections (which identify unwanted particles). The unwanted particles form locally clear-cut defects, which are concentrated upon the smallest space. In addition, they have a different behaviour from the good fibres; for example, neps (knotted fibres of less than about 1 mm diameter) are revealed as points of increased reflection and can hence be separated from the rest of the signal sequence. The individual particles are detected in contrast to the remaining card web, which 2 forms merely the background for them. The smaller the detection area of the card web is selected to be, the more prominently does a nep stand out. The disadvantage is that recording and assessment of the homogeneity of the card web in this way is not feasible. There is no provision in this for determining the distribution and orientation of the good fibres.

It is an aim of the invention to produce an apparatus which avoids or mitigates the said disadvantages, which in particular allows the homogeneity of the card web, in particular in respect of the distribution and orientation of the good fibres, to be recorded and assessed and improves the degree of uniformity of the web.

The invention provides an apparatus for examining a card web of textile fibres, comprising a camera, which is connected to an electronic evaluating device, wherein the camera is arranged to record good fibres and empty spaces within the card web, the measured values can be converted into electrical signals and supplied to the evaluating device, and the evaluating device is capable of determining the distribution of the good fibres in the card web per unit of area.

According to the invention, the good fibres and empty spaces, that is, the gaps between the good fibres, can be recorded and evaluated. From the ratio between the good fibres and the empty spaces per unit 3 of area, the homogeneity or web unevenness (opacity) is determined. In this way, the distribution and orientation of the good fibres in the card web is recorded. The measured values allow an image display and an optical and electronic evaluation. Inspection of the homogeneity enables defects in the region of the roller clothing or poor and/or faulty fibre material infeeds to be identified, and the quality of the card web to be improved. The homogeneity of the card web of the carding machine or similar machine can be recorded and assessed (evaluated) automatically and continuously, so that by way of the machine control system and the adjusting members an influence can be exerted on the processing of the fibre material. The larger the recorded surface area is selected to be, the more easily can the distribution of good fibres be recognised.

Advantageously, the numerical distribution is determinable. Preferably, the spatial distribution is determinable. The unwanted particles, for example, neps, are advantageously detectable and can be differentiated from the good fibres. The unwanted particles, for example, neps, are preferably disregarded when determining the distribution of the good fibres. The area proportions of the good fibres and of the empty spaces per unit of area are advantageously determined. The distribution of compactions and thinned regions in the good fibres is 4 preferably determined per unit of area. The distribution of compactions and thinned regions in the good fibres is advantageously compared with stored comparison values (standardising values) for the card web. The distribution of compactions and thinned regions is preferably compared with a homogeneous card web. Digital image data processing is preferably used with the evaluating device. The card web in free transit is preferably inspected between the stripping roller and the squeezing rollers of the carding machine.

The evaluating device is advantageously in connection with the machine control system. The evaluating device is preferably in connection with a higher-order electronic monitoring system, e.g. KIT. The camera advantageously records the card web in the longitudinal and transverse directions. The camera is preferably movable across the width of the card web. The good fibres and the empty spaces are advantageously recordable by the camera step-by-step. The camera preferably records the card web by sampling. The measurement results can advantageously be statistically evaluated.

The invention also provides an apparatus on a carding machine or similar machine, in which a card web of textile fibres, for example, cotton, man-made fibres or similar fibres, is formed, the card web comprising good fibres and empty spaces, and a measuring section S for the fibre material is provided, which has associated with it a camera, for example, a diode matrix camera, which is connected to an electronic evaluating device (image-processing computer), characterised. in that the good fibres and empty spaces are recordable by the camera, the measured values are arranged to be converted into electrical signals and supplied to the evaluating device and the evaluating device is capable of determining the distribution of the good fibres in the card web per unit of area.

Furthermore, the invention provides a method of inspecting a card web on a carding machine, in which the proportions of good fibres and empty spaces are optically recordable by a camera, and the electrical signals are used in a determination of the distribution of good fibres in the card web per unit of area.

one illustrative embodiment of the invention will be described in detail below with reference to the accompanying drawings, in which:

Fig. 1 is a schematic side view of a carding machine with a supporting and guiding member for receiving the camera and the illuminating device; Fig. 2 shows the apparatus according to the invention on the carding machine of Fig.

1 combined with a block circuit diagram and the card web to be recorded; 6 Fig.2a is a plan view from the front of the carriage movable back and forth with the camera and the illuminating device; 5 Fig. 3 is a side view of the apparatus in the carding machine, including an illustration of the photographed card web with the distribution of good fibres and empty spaces; Fig. 4 is a block circuit diagram of an arrangement suitable for use for the apparatus according to the invention; Fig. 5 is a plan view of the card web showing the photographed regions in the longitudinal and transverse directions; Fig. 6a shows the dependency of the homogeneity of the card web on time (longitudinal direction for a specific track); Fig. 6b shows the dependency of the homogeneity of the card web on time (transverse direction, mean value over all tracks); and 7 Fig. 6c shows the homogeneity of the card web (width distribution).

With reference to Figure 1 a carding machine, for example of the kind made by TrUtzschler GmbH & Co. KG and known as a high- performance DK 903 (trade mark) carding machine, has a feed roller 1, feed table 2, licker-ins 3a, 3b, 3c, cylinder 4, doffer 5, stripping roller 6, squeezing rollers 7, 8, web-guide element 9, web funnel 10, take-off rollers 11, 12 and revolving card top 13. A supporting and guiding member 14 is arranged beneath the stripping roller 6, and the upper squeezing roller 7 is arranged almost abutting the stripping roller 6. The directions of rotation of the cylinder 4 and the rollers are shown by respective curved arrows.

Referring to Fig. 2, the reference number 15 denotes the region in which the detached card web 16 is in transit from the stripping roller 6 to the squeezing rollers 7, 8. The supporting and guiding member 14 has essentially a four- cornered cross-section. The upper surface 14a is slightly concavely curved. The radius of curvature of the curve of the upper surface is greater than the radius of curvature of the stripping roller 6. The arrow A indicates the running direction of the card web 16. The element 14 is in the form of a housing, a transparent window 17 being provided in the sliding contact region. The card web is located 8 initially on the clothing of the doffer 5, is guided in the roller nip between the doffer 5 and the stripping roller 6 around and over the clothing 6a of the stripping roller 6, is detached from the stripping roller 6 a little way after the region of the perpendicular diameter, is guided in the region of the window 17 in direction A, following the end region runs completely freely and, finally, enters the roller nip between the squeezing rollers 7, 8 and passes between these. The upper surface 14a of the element 14 faces towards the clothing 6a of the stripping roller 6. one (upstream) end region of the element 14 is associated with the roller nip between the doffer 5 and the stripping roller 6. The other (downstream) end region 14b is arranged in the region between the stripping roller 6 and the squeezing rollers 7, 8, its edge being oriented in the direction of the roller nip between the squeezing rollers 7, 8. The element 14 is an extruded section, for example of aluminium, having an interior cavity. In the interior 14a of the housing 14, a camera 18, for example, a diode matrix camera, an illuminating device 19a, 19b (see Fig. 4), for example, comprising several light-emitting diodes, and an angled mirror 20 are arranged on a carriage 21. The angled mirror 20 is arranged at an angle between the lens 18a of the camera 18 and the illuminating device 19 on the one hand, and the inside of the window 17 on the other hand. The card web 16 runs on the outside of the 9 window 17. The wheels 22a, 22b of the carriage 21 run in guides in the inner wall of the housing 14 in directions B, C (see arrows B, C in Fig. 5) across the width of the machine.

In the region below the stripping roller 6 in which the web becomes detached, the camera 18 traverses across the operating width of the carding machine in the web guide member 14. The camera 18 delivers sharp images of the web 16, even at a production speed of 300 m/min, and transmits them to the image-processing computer 23, for example, a microcomputer and microprocessor. This evaluates the images 32a to 32g (see Fig. 5) according to the distribution of the good fibres in the card web 16 per unit of area. The results are indicated by way of the machine control system 24, (which may for example be of the kind made by Tratzschler GmbH & Co. KG and known as the CardCommander (trade mark)), on a display 25, and/or are passed to a card information system, for example a KIT 28 (trade mark) also made by TrQtzschler GmbH & Co. KG - see Fig. 4 - for further processing. A control element 26 and an adjusting means 27 for influencing the distribution of the good fibres in the card web 16 are arranged downstream of the machine control system 24. The means 27 can initiate measures to alter the fibre distribution in the card web 16, for example, it can alter the spacing between the card top clothings and the cylinder clothing of the carding machine, the speed of the cylinder, the spacing of a guide element from a roller, sharpening of the roller clothings and so on.

The apparatus according to the invention is simple to install in or remove from a carding machine. A periodic measurement on different carding machines is therefore possible.

For measurement, the card web 16 is conveyed in direction A. The card web 16 is recorded by the camera 18 through the viewing window 17. For this, incident light (see Fig. 2) and flash illuminations are combined. Evaluation is effected on the principle of the comparison of desired and actual values. The intensity of the light reflected by the web in relation to the intensity of the light beamed onto the web is used as a reference parameter. An incident light module may comprise a semiconductor flash lamp of high homogeneity and a command-controlled high-speed measuring camera 18 (with digital data output [e.g. 20 according to DE-A- 43 13 6211). A transmitted-light module may comprise a large-area high-intensity semiconductor flash lamp. In operation, the light is switched on in flashes and is controlled by the camera 18 or its control system. Light of different wavelengths can be used for the individual shots. In that case, more than one illuminating device can be used for one shot. For example, the incident light module can have more than 11 one illuminating device. Illumination can be effected from different directions. Illumination can also be effected from different sides (transmitted light and incident light). Light sources having different wavelengths can be used for illumination. The different directions, sides and wavelengths can also be combined with one another. Different illumination times (flash times) can be set.

The apparatus according to the invention allows automatic detection of and reduction in the unevenness of the card web 16. The important factor is detection at the card web 16, when it is detached from the stripping roller 6 and is therefore free. The invention is explained by the example of a carding machine having a revolving card top. It includes also other machines in which a card web is produced, for example, a card having fixed or roller card elements.

In Fig. 3, the photographed card web 16 comprising good fibres and empty spaces can be seen on the display screen 25. The homogeneity (opacity), that is, the distribution and orientation of the good fibres, is shown. In the embodiment of Fig. 3, the lens 18a of the camera 18 is directed upwards onto the card web 16 without an angled mirror.

In the embodiment shown in Fig. 2a, the camera 18 and the illuminating device 19a, 19b are arranged pointing upwards towards the window 17, the card web 16 and the stripping roller 6.

12 In the embodiment of Fig. 4 there is a camera 18, downstream of which are arranged the image-processing computer 23, the card control device 24 and the display unit 2S. If the recorded information is passed to the card control system 24 and from there to other higherorder monitoring systems (e.g. KIT 28), then, for example, a comparative inspection across several machines is also possible. Moreover, comparisons with earlier results can be drawn. The reference number 33 denotes the carding machine.

As shown in Fig. 5, the camera 18 continuously supplies samples in the longitudinal and transverse directions of the web 16. Evaluation of the images taken is effected by methods of digital image data processing. By applying suitable mathematical processes, statistically based interpretations are possible inter alia about the quality (homogeneity) of the web.

The reference letter A denotes the direction of movement of the card web 16. The reference number 31 denotes the area of movement, and B and C denote the directions of movement of the camera 18. The images recorded by sampling are marked 32a to 32g.

Using known card web structures it is possible to determine a scaling factor, so that, for example, timedependent quality data can be specified both for the length (A) and also the transverse direction (B, C) of the card web 16. For example, a very good web can be 13 given the factor 10 and a very poor web the factor 0. In this way, corresponding interpretations are possible (Figs 6 a-c). A similar procedure can be applied to the width distribution (very good width distribution = 5 10, very poor width distribution = 0).

The camera 18 contains an optical part and an electronic part with a CCD chip. The camera 18 can also be a diode line camera.

claims 1. An apparatus for examining a card web of textile fibres, comprising a camera, which is connected to an electronic evaluating device, wherein the camera is arranged to record good fibres and empty spaces within the card web, the measured values can be converted into electrical signals and supplied to the evaluating device, and the evaluating device is capable of determining the distribution of the good fibres in the card web per unit of area.

2. An apparatus according to claim 1, in which a numerical distribution of the fibres is determinable.

3. An apparatus according to claim 1 or claim 2, in which a spatial distribution is determinable.

4. An apparatus according to any one of claims 1 to 3, in which unwanted particles are detectable and capable of being be differentiated from the good fibres.

5. An apparatus according to claim 4, in which the unwanted particles are disregarded when determining the distribution of the good fibres.

6. An apparatus according to claim 4 or claim 5, in which the unwanted particles to be detected are neps.

7. An apparatus according to any one of claims 1 to 6, which is arranged to determine the area proportions of the good fibres and of the empty spaces per unit of area.

8. An apparatus according to any one of claims I to 7, which is arranged to determine the distribution of compactions and thinned regions in the good fibres per unit of area.

9. An apparatus according to claim 8, which is arranged to compare the distribution of compactions and thinned regions in the good fibres with stored comparison values (standardising values) for the card web.

10. An apparatus according to claim 8 or claim 9, which is arranged to compare the distribution of compactions and thinned regions with a homogeneous card web (statistical distribution).

11. An apparatus according to any one of claims 1 to 10, in which the evaluating device is arranged to use digital image data processing.

12. An apparatus according to any one of claims 1 to 11, in which the camera is arranged to record the card web by sampling.

13. An apparatus according to any one of claims 1 to 12, in which the evaluating device is arranged to evaluate the measurement results statistically.

14. An apparatus according to any one of claims 1 to 13, in which the evaluating device is in connection with a higher- order electronic monitoring system.

15. An apparatus according to any one of claims 1 to 14, in which the evaluating device is a 16 microcomputer with microprocessor.

16. An apparatus on a carding machine or similar machine, in which a card web of textile fibres, for example, cotton, man-made fibres or similar fibres, is formed, the card web comprising good fibres and empty spaces, and a measuring section for the fibre material is provided, which has associated with it a camera, for example, a diode matrix camera, which is connected to an electronic evaluating device (image -processing computer), characterised in that the good fibres and empty spaces are recordable by the camera, the measured values are arranged to be converted into electrical signals and supplied to the evaluating device and the evaluating device is capable of determining the distribution of the good fibres in the card web per unit of area.

17. An apparatus for examining a card web substantially as described herein with reference to and as illustrated by any of Figs. 1, Fig. 2, Fig. 2a, Fig. 3, Fig. 4, Fig. S and Figs. 6a to 6c.

18. A carding machine comprising an apparatus according to any one of claims 1 to 17.

19. A machine according to claim 18, in which the apparatus is arranged for inspection of the card web in free transit between a stripping roller and squeezing rollers of the carding machine.

20. A machine according to claim 18 or claim 19, in which the evaluating device is in connection with 17 the machine control system, for example, a computer.

21. A machine according to any one of claims 18 to 20, in which the camera is arranged to record the card web in the longitudinal direction and transverse directions.

22. A machine according to any one of claims 18 to 21, in which the camera is movable across the width of the card web.

23. A machine according to any one of claims 18 to 22, in which the good fibres and the empty spaces are recordable by the camera stepwise.

24. A machine according to any one of claims 18 to 23, in which the control device of the machine is a microcomputer with microprocessor.

25. A method of inspecting a card web on a carding machine, in which the proportions of good fibres and empty spaces are optically recordable by a camera, the measurement values are converted into electrical signals, and the electrical signals are used in a determination of the distribution of good fibres in the card web per unit of area.

26. A method according to claim 25, in which the carding machine is adjusted in dependence on the determined distribution.