Method and device for controlling a treatment installation for textile fibres, in particular cotton fibres

Abstract

Textile fibers, in particular cotton fibers, in a treatment installation by way of a transport system are supplied after one another to various treatment stations. With this the fibers are at least cleaned and homogenized. With a sensor system (10) continuously at least two different physical variables (22) are detected at the fibers. From the detected variables certain fiber properties are deduced and actual values are formed which in an evaluation means (8, 9) are compared to a nominal value (24) for each fiber property. With the presence of deviations from a nominal value the operating condition at least of one treatment station and/or of the transport system is changed. With this the whole treatment process is to be optimized.

Description

[0001] The invention relates to a method for controlling a treatment installation for textile threads, in particular cotton threads, according to the preamble of claim 1. Such a treatment installation with yarn production is also described as an blow room/carding plant. With this, from unordered cotton threads there is manufactured a carding web which subsequently by way of drawing, combing and spinning is processed into a yarn. On the producer level in the context of the harvested cotton capsules one speaks of a shelling or ginning installation. Here the grains are separated from the fibres and where appropriate further impurities are removed.

[0002] There are already known numerous methods with whose help foreign matter is recognised and may extracted from the fibre material flow. On account of the differing fibre properties up to now one did not pay any attention to the control of the complete working process and in particular the spinning capability of the fibre material. The fibre properties are as a rule only determined by way of random samples, which however often leads to bad fibre mixtures and to insufficient information on the properties of the processed carding webs. It is already known by way of U.S. Pat. No. 5,892,142 at the stage of the fibre production with the so-called ginning process by way of an automatic method to remove random samples from a fibre flow at regular distances and to test these samples for various parameters such as dampness, colour or fibre content. The measuring results are led to a central computer and may be evaluated in this manner. This method however is mechanically very complicated and permits no quick intervention in the fibre material flow, for example within a time interval of a few seconds or even milliseconds.

[0003] It is therefore the object of the invention to provide a method of the above mentioned type which permits an optimisation of the working process in the blow room/carding plant or in the ginning installation, on account of certain material properties. This object according to the invention is achieved with a method which has the features of claim 1. With this no random samples are made, but the fibre material flow is continuously monitored for at least two different physical variables. From these variables either individually or in combination or sub-combination there may be deduced various material properties. On account of a comparison with previously inputted nominal values one may intervene in the treatment stations or in the transport system. The expression material properties is to be understood also as various degrees of contamination of the fibres or flocks, wherein impurities may occur directly on the surface of the fibres or however as a separate admixture. Homogenisation is to be understood as the achieving of a uniform as possible fibre mixture.

[0004] Preferably at the sensor system a plurality of properties of the material are detected. With this it may be the case of flock properties (size, density, distribution, colour, shape, dampness, temperature) or fibre properties—(surface coating with natural wax or artificial substances, fibre fineness, fibre maturity, fibre length, staple distribution) or where appropriate other properties. The maturity of the cotton may be deduced from the wavelength region 1500 to 1550 nm and the dampness from the wavelength region around 1900 nm. Correlations with respect to surface properties of fibres, in particular dependencies on dampness and chemical composition are described in “Duckett, K. E., Surface Properties of Cotton Fibers,” in “Fiber science Series, Surface Characteristics of Fibers and Textiles, Part I, M. J. Schick, Ed., Marcel Dekker, N.Y. 1975”. Details for recognising the wax coating are amongst others described in “Measuring Natural Waxes on Cotton using NIR Absorbance, R. A. Taylor and L. C: Godbey, USDA, ARS, Cotton Quality Res. station, Clemson, S. C.”. One may also detect the presence of foreign matter, wherein under the category foreign matter fall foreign fibres of a natural origin, plastic material, vegetable foreign matter, metals, mineral foreign matter, neps, animal secretions, in particular honey dew, remains of textiles and more.

[0005] Since the sensor system must detect physical variables on the fibre material flow which flows past, in particular there are suited contactless sensors, which emit or receive electromagnetic waves and/or ultrasound waves. In certain individual cases tactile sensors would however also be conceivable, for example in the form of measuring probes which project into the fibre material flow and e.g. measure the flow resistance, the electrical conductability, the impulse of the flocks or particles, etc. With sensors based on electromagnetic waves above all those near the infra-red region are particularly suitable in order in the reflected or transmitted spectrum to recognise a larger range of materials or properties. With at least two characteristic frequencies one may define a “finger print” from which various material properties may be deduced.

[0006] Fibre dimensions, in particular the fibre fineness may be particularly advantageously detected with laser sensors. For this purpose a diffraction pattern and or scatter pattern is formed.

[0007] Of course however also other electromagnetic waves are conceivable such as e.g. ultra-violet, visible light or also X-rays.

[0008] The variables may be detected with at least two sensors at, with regard to the transport direction, different locations or the treatment installation. Thus e.g. an electromagnetic sensor for metal parts and an optical sensor for dampness or wax coating would be conceivable. It is however also possible that a sensor functions at several frequencies or measuring principles and that in this manner two or more measuring signals at the same location of the fibre material flow may be detected.

[0009] It may also be particularly advantageous when the variables are detected and evaluated at differing time intervals. According to the material property concerned specifically the detected actual values demand different reaction times. Thus for example an ascertained contamination must be discarded within milliseconds after the detection by way of a pressure impingement or by way of a deflection flap. An influence of the bale cutter may be effected in the region of seconds, whilst the duration of the control intervention given a changing moisture content may be e.g. 5 to 10 minutes and the average value from measurements may be formed in larger time intervals.

[0010] In an blow room/carding plant the treatment stations are preferably connected to a pneumatic transport system. With this it is where appropriate necessary to remove the conveying air in front of a treatment station and to supply this again after the treatment station. However also other conveying systems such e.g. conveyor belts or conveyor worms would be conceivable.

[0011] A considerable process optimisation may already be achieved when the fibres are presented as bales and by way of a bale opening machine are opened, run through an extractor, are led to at least one mixer and subsequently at least one carding machine are processed into web, wherein via the evaluation means on recognising foreign matter the extractor is activated and on recognising other material properties the mixer is activated for changing the mixture ratio. In this manner not only as was usual up to now is foreign matter reliably extracted but there also takes place a continuous influencing of the mixture ratio so that a homogeneous as possible fibre mixture is produced in order constantly to strive for an optimal spinning capability. Additionally, on recognising deviating material properties the carding machine or another treatment station are activated for changing the machine parameters. Finally it is also conceivable on recognising foreign matter and/or deviating material properties to activate the bale opening machine for changing the opening movement. Thus for example a certain bale may be identified which delivers an above average high share of contaminated fibres or fibres deviating in a different manner. The opening movement may at the same time be controlled such that in each case at these bales the opening depth and/or speed may be changed until a manual sorting-out is possible.

[0012] Basically however also yet very different processing stations such as e.g. flock opening machines, fine cleaners, coarse cleaners and likewise may be activated. The method according to the invention permits also a protocolling with respect to data of the process and a classification of the intermediate products and thus an optimization of the quality control.

[0013] The influencing of the transport system is in particular also to be understood as the jumping of a treatment means in a by-pass conduit. Alternatively the fibre material flow at a conveying parting may, according to the fibre properties, be led to differing treatment stations.

[0014] The invention relates also to a device for controlling a treatment installation for textile fibres, in particular cotton fibres, which is characterised by the features in claim 16.

[0015] One embodiment example of the invention is shown in the drawings and is explained hereinafter. There are shown in

[0016] FIG. 1 a symbolic representation of the most important treatment installations in an blow room with a subsequent carding room,

[0017] FIG. 2 a schematic representation of a treatment course with the interactive relations with respect to control technology,

[0018] FIG. 3 the schematic representation of the correlation between various measuring signals and material properties, and

[0019] FIG. 4 a symbolic representation of the most important treatment installations in a ginning installation.

[0020] As is shown in FIG. 1 an blow room line/carding room 1 consists of a bale opening machine 3, of a pre-cleaner 19, of an extractor 4, of a mixer 5, of a fine cleaner 6, where appropriate of a second fine cleaner 6′ and of a carding machine 7. The individual treatment stations are connected to one another via a pneumatic transport system 2. With this from the individual bales 11 in layers fibre flocks are removed and in the already broken-up form are led to the foreign matter extractor 4 pre-cleaned. This has at its disposal a sensor system, for example in the form of CCD cameras 12 with whose help changes with respect to colour may be ascertained. Coloured foreign matter with this is extracted. Simultaneously also NIR sensors 13 may yet be provided which for example detect the degree of dampness, the wax coating or other parameters.

[0021] Subsequently the fibres are led to a mixer 5 which is equipped with various feed hoppers 14. The material columns in the individual hoppers are compacted by their intrinsic weight and then again opened together in layers. With this there is effected a through-mixing of the various fibre charges. However there are also known other mixer types.

[0022] At the fine cleaner 6 and 6′ by way of toothed clothings impurities such as e.g. pod parts, dirt, sand, etc. are separated from the fibres and cast away. Finally the purified fibres reach the carding machine 7 where in the manner known per se are processed into a carding web 15.

[0023] The sensor system is advantageously installed in front of the mixer 5 so that one may intervene in the mixing procedure or so that an intervention at the bale opening is delay-free as possible. The sensor system should furthermore be arranged at a location where the fibres or flocks are presented in a suitable manner. This may for example be also on the extension arm of the bale opening machine 3, in the region of an opening member or directly in a suitable region of the fibre transport conduit.

[0024] With respect to the construction and the manner of acting of the sensor arrangement the subsequent prior publications may for example be referred to, the contents of which are expressly herewith declared as the contents of the disclosure:

[0025] Uhlmann Jürg, “Fremdstoff in der Rohbaumwolle” Diss. Eidgenössische Technische Hochschule, Zürich, 1996

[0026] WO 96/35831

[0027] DE U 297 19 245.0

[0028] EP A 893 516

[0029] In the diagram according to FIG. 2 there is once again schematically shown a blow room line/carding plant. With this the cotton bales are removed from a storage and at 16 are prepared for the bale opening, i.e. are freed from the outer covering and identified with respect to the cited storage data. At 17 the bales are presented in order to be opened by way of the bale opening machine 3.

[0030] The flocks are opened at 18 in order to be presented to the sensor system 10 in as suitable form as possible. Subsequently the flocks of fibres reach the extractor 4 where foreign matter is extracted. At 19 there is effected a precleaning of the flocks, where above all vegetable waste is extracted. At 20 there is effected a metering of the flocks so that these may be supplied in a classed and metered form to the mixer 5 or preferably several mixers. After the mixing there is effected a fine cleaning in the cleaner 6. Here there is effected a disgarding of fine plant parts and other foreign matter such as sand, etc. only now do the purified flocks reach the carding machine 7 where the carding web 15 for the further processing is filled into a can 21. Of course as shown in FIG. 1 the pre-cleaner 19 may also be arranged between the bale opening machine 3 and the extractor 4. Also the number and arrangement of the fine cleaners in the line may vary.

[0031] The sensor system 10 may of course also be arranged at a different location, or various sensors which function according to different physical principles may be arranged at different locations of the fibre transport conduit. The sensor system conveys different physical variables 22 to an evaluation means 8. Here actual values 23 may be called up for various fibre properties. In a control means 9 the actual values are compared to inputted nominal values 24. The thus determined deviations form control signals 25 for influencing various machine parameters. Thus on detecting foreign matter the extractor 4 is actuated and/or the mixing process, the cleaning process or the carding process is influenced. At the bale presentation 17 or at the bale preparation 16 there may be set jobs in order to remove or exchange certain bales.

[0032] It is yet to be mentioned that in the course of the opening process the bales are identified by identification signals 26 which permits the tracing of fibre properties to the corresponding bales.

[0033] With the representation according to FIG. 3 it is to be made clear that different variables 22 at the sensor system 10 may be used for identifying various material properties 27, whilst exploiting correlation methods to be previously determined. With the three various matrices M1, M2 and M3 it is shown that for the signal formation, signals also detected over different time periods may be taken into account. Thus for example a near-infrared sensor may have the frequency regions A, B, C wherein each region correlates to certain material properties a, b, c, d or e. With this it may be the case of the moisture content, the maturity degree, foreign matter, the wax coating or another variables. At the matrix M1 the detected signals for very short-term control interventions in the millisecond region may be evaluated for the extraction of foreign matter.

[0034] At the matrix M2 from the variables A, B and G one may deduce the fibre properties c, e, f and 9, e.g. the stickiness, which however may be used for the medium-term control intervention in the second region. Thus for example the bale opening machine may jump a certain bale when here there is ascertained a certain fibre quality and/or a heavy contamination, or limit the opening of these components within the context of a controlled admixture.

[0035] At the matrix M3 from the variables D, E and F one deduces the fibre properties a, b, c, d and g, e.g. moisture. Here there are actuated rather longer lived control interventions in the minute region, e.g. in order to change the machine parameter of a cleaner or of a carding machine or in order to change the room climate.

[0036] As a whole the sensor system may be extended in any manner in order to optimise the processing process. Of course it does not necessarily have to concern a processing installation for cotton fibres. Also processing processes for animal fibres or in certain cases for synthetic fibres may be controlled in the same manner.

[0037] FIG. 4 shows schematically a ginning installation 42 which likewise is controllable with the method according to the invention. The fibre properties with this are not determined as in the state of the art by way of periodically taken samples, but continuously at the material flow.

[0038] From harvesting vehicles 44 the raw cotton is unloaded into a buffer storer 45 and here is layered. Here there is effected a first homogenisation of the flocks. In the ginning installation the cotton pneumatically reaches a feed module 28 and then in a sand extractor 29 is subjected to a first cleaning process. Subsequently the cotton runs through a first tower dryer 30 and after passing a first crossroll cleaner runs through an extractor machine 31 for larger plant parts. In a second tower dryer 32 the excess dampness of the fibres is removed. A second crossroll cleaner 39 and an impact cleaner 34 remove further foreign matter before the cotton fibres are led to a cleaner (extractor) 35. Directly therebelow there is arranged a ginning machine (gin) 36. Here to the first degree vegetable foreign matter such as e.g. seed grains, pods, etc. are removed. The fibres finally reach a fibre cleaner 37 (lint cleaner), where the valuable fibre parts of the cotton plant are further cleaned. The pneumatic further transport leads finally to a bale press 38.

[0039] For the influencing of the machine—or conveying parameters, before the first tower dryer 30 or where appropriate already after the buffer storer 45 there is arranged a first sensor 40. A second sensor 41 is arranged in the transition region between the cleaner (extractor) 35 and the ginning machine 36. The two sensors 40 and 41 as well as where appropriate further sensors may be used to control the tower dryer, the ginning machine and the fibre cleaner and in order to extract foreign matter so that fibre bales 43 of a known quality which is as consistent as possible may be manufactured.

Claims

1. A method for controlling a treatment installation for textile fibres, in particular cotton fibres, before the spinning, with which the fibres by way of a transport system continuously in one go pass through various treatment stations after one another and with this are in particular at least cleaned and homogenised, characterised in that

during the transport of the fibres with a sensor system continuously at least two different physical variables are detected at the fibres,

that from the detected variables in an evaluation means there is derived an actual value for certain material properties which is compared to a nominal value for each material property,

and that with the presence of deviations from a nominal value the operating condition of least of one treatment station and/or transport system is changed.

2. A method according to

claim 1, characterised in that at least one of the following properties is determined

colour,

dampness,

surface coating (stickiness, wax content),

temperature,

flock size and density, flock distribution, flock mass, flock speed,

fibre fineness

fibre or flock purity,

fibre length (staple distribution).

3. A method according to one of the claims 1 or 2, characterised in that at the sensor system the presence of foreign matter is detected.

4. A method according to

claim 3, characterised in that the presence of at least one of the following foreign matter is detected:

foreign fibres of a natural origin,

plastic material,

vegetable foreign material,

metals,

mineral foreign material,

neps,

animal secretion, in particular honey dew,

agricultural agents.

5. A method according to one of the

claims 1 to

4, characterised in that the sensor system emits or receives electromagnetic waves and reacts to at least two different wave spectra.

6. A method according to

claim 5, characterised in that the sensor system functions in the near infrared region.

7. A method according to one of the

claims 1 to

4, characterised in that the sensor system sends or receives ultrasound waves.

8. A method according to one of the

claims 1 to

7, characterised in that the sensor system detects the variables with at least two sensors at, with regard to the transport direction, various locations of the treatment installation.

9. A method according to one of the

claims 1 to

8, characterised in that the fibres run through or run up to the treatment stations with a pneumatic transport system.

10. A method according to one of the

claims 1 to

9, characterised in that the variables are averaged or evaluated at different time intervals.

11. A method according to one of the

claims 1 to

10, characterised in that with the processing of raw cotton (ginning) it takes place between the feeding of the cotton capsule and the pressing of the purified cotton fibres into bales.

12. A method according to one of the

claims 1 to

10, characterised in that with the processing of cotton fibres in the spinning mill it takes place between the opening of the cotton bales and the carding into a fibre fleece.

13. A method according to

claim 12, characterised in that the fibres

are presented as bales and are opened by way of a bale opening machine,

run through an extractor

are supplied to at least one mixer,

and subsequently at least one carding machine are processed into a web,

wherein via the evaluation means on recognising foreign matter or with material deviating greatly from a nominal value the extractor is activated and on recognising other deviations the mixer is activated for changing the mixing ratio.

14. A method according to

claim 13, characterised in that on recognising other deviations additionally a cleaner and/or a carding machine is activated for changing the machine parameters.

15. A method according to one of the

claims 12 to

14, characterised in that on recognising foreign matter and/or other deviations the bale opening machine is activated for changing the opening movement.

16. A device for controlling a treatment installation for textile fibres, in particular cotton fibres, before the spinning, with several treatment stations, in particular with at least one cleaner and with a homogenising means, and with a transport system for the continuous transport of the fibres in one go through the treatment stations, characterised by

a sensor system with which at least two different physical variables are detectable at the fibres,

an evaluation means with a nominal value setter for at least one material property, in which from various variables there may be derived an actual value of this material property which may be compared to a nominal value,

and a control means for changing the operating condition of at least one treatment station and/or the transport system given the presence of deviations of the detected actual values from a nominal value.

17. A device according to

claim 16, characterised in that the sensor system comprises at least one sensor, which emits or receives electromagnetic waves of different wave spectra.

18. A device according to

claim 17, characterised in that at least one sensor is a near infra-red sensor.

19. A device according to

claim 16, characterised in that the sensor system comprises at least one ultrasound sensor.

20. A device according to one of the

claims 16 to

19, characterised in that the sensor system comprises at least two individual sensors which with regard to the transport direction are arranged at various locations of the treatment installation.

21. A device according to one of the

claims 16 to

21, characterised in that the transport system is a pneumatic transport system and that the sensor system is directly allocated to at least one section of the fibre transport conduit.

22. A device according to one of the

claims 16 to

21, characterised in that the treatment installation as treatment stations in series comprises

a bale opening machine

an extractor,

a mixer

and a carding machine,

and that via the control means on recognising foreign matter or greatly deviating material the extractor is activatable, and on recognising other deviating material properties the mixer is activatable.

23. A device according to

claim 22, characterised in that additionally a cleaner and/or a carding machine is activatable.

24. A device according to

claim 22 or

23, characterised in that additionally the bale opening machine is activatable.