EP1123995B1 - Method and apparatus for controlling a textile fibre processing plant, especially for cotton fibres - Google Patents

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

The invention relates to a method for controlling a treatment plant for textile fibers, in particular cotton fibers, according to the preamble of claim 1. Such a treatment plant is also referred to as a blow room / carding machine in yarn production. A card sliver is made from disordered cotton fibers, which is then processed into a yarn by stretching, combing and spinning. At the producer level there is talk of a ginning plant or ginning plant in connection with the harvested cotton capsules. There the seeds are separated from the fibers and, if necessary, further impurities are removed.

Numerous methods are already known with the aid of which foreign substances can be recognized and separated from a stream of fiber material. The control of the entire work process and in particular the spinnability of the fiber material due to different fiber properties has so far been neglected. As a rule, the fiber properties are only determined by means of random samples, which, however, often leads to poor fiber mixtures and insufficient information about the properties of the processed card slivers. It is already known, for example, from US Pat. No. 5,892,142 at the fiber production stage in the so-called ginning process, to take samples from a fiber stream at regular intervals by means of an automated method and to measure these for various parameters such as moisture, color or fiber fineness. The measurement results are fed to a central computer and can be used in this way. This method is mechanically very complex and does not allow rapid interventions in the fiber material flow, for example within a period of a few seconds or even milliseconds.

It is therefore an object of the invention to provide a method of the type mentioned at the outset which enables an optimization of the work process in the blow room / carding machine or in the ginning installation on the basis of certain material properties. This object is achieved according to the invention with a method which has the features in claim 1. No samples are taken, but the fiber material flow is continuously monitored for at least two different physical measurement parameters. Different material properties can be derived from these measurement parameters either individually or in combination or sub-combination. On the basis of a comparison with previously entered target values, it is possible to intervene in the treatment stations or in the transport system. The term material properties is also understood to mean different degrees of soiling of the fibers or flakes, impurities being able to occur directly on the surface of the fibers or as a separate admixture. Homogenizing is understood to mean achieving a fiber mixture that is as uniform as possible.

A plurality of properties of the material are preferably determined on the sensor system. These can be flake properties (size, density, distribution, color, shape, moisture, temperature) or fiber properties (surface coating with natural wax or artificial substances, fiber fineness, maturity, length, stack distribution) or other properties if necessary. The ripeness of the cotton can be determined from the wavelength range 1500 to 1550 nm and the moisture derive from the wavelength range around 1900 nm. Relationships with regard to surface properties of fibers, in particular dependencies on moisture and chemical composition, are described in "Duckett, KE, Surface Properties of Cotton Fibers", in "Fiber Science Series, Surface Characteristics of Fibers and Textiles, Part I, MJ Schick, Ed. , Marcel Dekker, NY 1975 ". Information on the detection of the wax coating is described, inter alia, in "Measuring Natural Waxes on Cotton using NIR Absorbance, RA Taylor and LC Godbey, USDA, ARS, Cotton Quality Res. Station, Clemson, SC". However, the presence of foreign substances can also be determined, whereby foreign substances of natural origin, plastic material, vegetable foreign material, metals, mineral foreign material, nits, animal secretions, in particular honeydew, remnants of textiles and other fall under the category of foreign substances.

Since the sensor system has to determine the physical measurement quantities of the fiber material stream flowing past, contactless sensors that transmit or receive electromagnetic waves and / or ultrasound waves are particularly suitable. In certain individual cases, however, tactile sensors would also be conceivable, for example in the form of sensors that protrude into the fiber material flow and, for. B. measure the flow resistance, the electrical conductivity, the momentum of the flakes or particles, etc. In the case of sensors based on electromagnetic waves, the near infrared range is particularly well suited to recognizing a large number of substances or properties in the reflected or transmitted spectrum. With at least two characteristic frequencies, a "fingerprint" can be defined, from which different material properties can be derived.

Fiber dimensions, in particular fiber fineness, can be determined particularly advantageously with laser sensors. A diffraction pattern and / or control pattern is formed for this purpose.

Of course, other electromagnetic waves are also conceivable, e.g. Ultraviolet, visible light or X-rays.

The measured variables can be determined with at least two sensors at different points in the treatment system, based on the transport direction. For example, an electromagnetic sensor for metal parts and an optical sensor for moisture or wax coating are conceivable. However, it is also possible for a sensor to work on several frequencies or measuring principles and for two or more measurement signals to be determined in this way at the same point in the fiber material flow.

It can also be particularly advantageous if the measured variables are averaged or evaluated in different time periods. Depending on the material property concerned, the actual values determined require different reaction times. For example, a detected contamination must be eliminated by a pressure surge or a deflection flap within milliseconds after detection. The bale cutter can be influenced in a matter of seconds, while the duration of the control intervention with changing moisture content e.g. Can be 5 to 10 minutes or the mean value is formed from measurements in larger time segments.

In a blow room / carding station, the treatment stations are preferably connected to a pneumatic transport system. there it may be necessary to remove the conveying air before a treatment station and to supply it again after the treatment station. But other conveyor systems such as conveyor belts or screw conveyors would also be conceivable.

Considerable process optimization can already be achieved if the fibers are presented as bales and removed by means of a bale removal machine, passed through a separator, fed to at least one mixer and then processed at least on a card to form a band, with the evaluation device detecting foreign substances the separator is activated and when other material properties are recognized, the mixer is activated to change the mixing ratio. In this way, foreign substances are not only reliably excreted, as was previously the case, but there is also a continuous influencing of the mixing ratio, so that fiber mixtures which are as homogeneous as possible are produced in order to always strive for optimal spinnability of the fibers. In addition, when different material properties are detected, the card or another treatment station can be activated to change the machine parameters. Finally, it is also conceivable to control the bale removal machine to change the removal movement when foreign substances and / or deviating material properties are detected. For example, a specific bale can be identified that delivers an above-average proportion of soiled or otherwise deviating fibers. The removal movement can be controlled in such a way that the removal depth and / or speed is changed on each bale until manual rejection is possible.

In principle, however, completely different processing stations, such as flake dissolving machines, fine cleaners, coarse cleaners, can also be used and the like can be controlled. The method according to the invention also permits data logging of the process and classification of the intermediate products and thus optimization of the quality control.

Influencing the transport system is also to be understood in particular as the skipping of a treatment device in a bypass line. Alternatively, the flow of fiber material could be fed to different treatment stations on a conveyor switch depending on the fiber properties.

The invention also relates to a device for controlling a treatment plant for textile fibers, in particular cotton fibers, which is characterized by the features in claim 16.

Figur 1

eine symbolische Darstellung der wichtigsten Behandlungsanlagen in einer Putzerei mit anschliessender Karderie,

Figur 2

eine schematische Darstellung eines Behandlungsablaufs mit den steuertechnischen Wechselbeziehungen,

Figur 3

die schematische Darstellung der Korrelation zwischen verschiedenen Messsignalen und Materialeigenschaften, und

Figur 4

eine symbolische Darstellung der wichtigsten Behandlungsanlagen in einer Entkörnungsanlage (GinningAnlage).

An embodiment of the invention is shown in the drawings and is explained below. Show it:

Figure 1

a symbolic representation of the most important treatment facilities in a blow room with subsequent carding,

Figure 2

a schematic representation of a treatment process with the tax-technical interrelations,

Figure 3

the schematic representation of the correlation between different measurement signals and material properties, and

Figure 4

a symbolic representation of the most important treatment plants in a ginning plant (ginning plant).

As shown in FIG. 1, a blowroom line / carding machine 1 consists of a bale removal machine 3, a pre-cleaner 19, a separator 4, a mixer 5, a fine cleaner 6, possibly a second fine cleaner 6 'and a carding machine 7. The individual treatment stations are over a pneumatic transport system 2 connected to each other. In this case, fiber flakes are removed in layers from the individual bales 11 and fed to the foreign matter separator 4 in a pre-cleaned form in already dissolved form. This has a sensor system, for example in the form of CCD cameras 12, with the aid of which color changes can be determined. Colored foreign substances are excreted. At the same time, NIR sensors 13 can also be provided, which for example determine the degree of moisture, the wax coating or other parameters.

The fibers are then fed to a mixer 5 which is equipped with various filling chutes 14. The material columns in the individual shafts are compacted by their own weight and then again removed in layers. The various fiber batches are mixed. However, other types of mixers are also known.

On the fine cleaner 6 or 6 ', impurities such as e.g. Shell parts, dirt, sand etc. separated from the fibers and flung away. Finally, the cleaned fibers arrive at the card 7, where they are processed into a card sliver 15 in a manner known per se.

The sensor system is advantageously installed in front of the mixer 5, so that the mixing process can be intervened or an intervention in the bale removal can be carried out as quickly as possible. The sensor system should also be arranged at a location where the fibers or flakes are suitable to get presented. This can also be, for example, on the boom of the bale removal machine 3, in the area of an opening member or directly in a suitable area of the fiber transport line.

• Uhlmann Jürg, "Fremdstofferkennung in der Rohbaumwolle" Diss. Eidgenössische Technische Hochschule, Zürich, 1996
• WO 96/35831
• DE U 297 19 245.0
• EP A 893 516

With regard to the structure and mode of operation of the sensor arrangement, reference may be made, for example, to the following pre-publications, the content of which is hereby expressly declared to be the disclosure content:

• Uhlmann Jürg, "Detection of foreign substances in raw cotton" Diss. Swiss Federal Institute of Technology, Zurich, 1996
• WO 96/35831
• DE U 297 19 245.0
• EP A 893 516

A cleaning line / carding machine is again shown schematically in the diagram according to FIG. The cotton bales are removed from a warehouse and prepared at 16 for bale removal, i.e. freed from the outer wrapping and identified with respect to the specified warehouse data. At 17, the bales are placed in order to be removed by means of the bale removal machine 3.

The flakes are opened at 18 in order to be presented to the sensor system 10 in the most suitable form. The flakes or fibers then reach the separator 4, where foreign substances are removed. At 19, the flakes are pre-cleaned, where mainly vegetable waste is excreted. At 20, the flakes are dosed so that they can be fed to the mixer 5 or preferably several mixers in a classified and dosed form. After mixing, the fine cleaning takes place in cleaner 6. There is an excretion of fine plant parts and other foreign matter such as sand, etc. Only now do the cleaned flakes reach card 7 where the card sliver 15 is filled into a can 21 for further processing. Of course, as shown in FIG. 1, the pre-cleaner 19 could also be arranged between the bale removal machine 3 and the separator 4. The number and arrangement of fine cleaners in the line can also vary.

The sensor system 10 could of course also be arranged at a different location, or different sensors that work according to different physical principles could be arranged at different locations on the fiber transport line. The sensor system transmits different physical measurement variables 22 to an evaluation device 8. Actual values 23 for different fiber properties can be called up there. In a control device 9, the actual values are compared with entered target values 24. The deviations determined in this way form control signals 25 for influencing various machine parameters. Thus, when determining a foreign substance, the separator 4 is actuated and / or the mixing process, the cleaning process or the carding process is influenced. Orders can be placed on the bale feed 17 or on the bale preparation 16 in order to remove or replace certain bales.

It should also be mentioned that in the course of the removal process, the bales are identified by identification signals 26, which enables fiber properties to be traced back to the corresponding bales.

The illustration according to FIG. 3 is intended to clarify that different measurement variables 22 on the sensor system 10 are used for this can be used to identify various material properties 27 using correlation methods to be determined beforehand. The three different matrices M1, M2 and M3 show that signals averaged over different time periods can also be taken into account for the signal formation. For example, a near infrared sensor can have the frequency ranges A, B, C, with each range correlating with specific material properties a, b, c, d or e. This can be the moisture content, the degree of maturity, foreign substances, the wax coating or another size. The signals determined for very short-term control interventions in the millisecond range for the excretion of foreign substances can be evaluated on the matrix M1.

The fiber properties c, e, f and g, e.g. the stickiness, derived, but which are used for medium-term tax interventions in the range of seconds. For example, the bale removal machine could skip a certain bale if a certain fiber quality and / or a strong contamination is found there, or limit the removal of this component in the sense of a controlled admixture.

On the matrix M3, the measured variables D, E and F are used to determine the fiber properties a, b, c, d and g e.g. Moisture closed. Rule interventions lasting longer are triggered here, e.g. to change the machine parameters of a cleaner or a card or to change the indoor climate.

Overall, the sensor system can be expanded as required to optimize the processing process. Of course, it does not necessarily have to be a processing plant for cotton fibers. Processing processes for Animal fibers or, in certain cases, synthetic fibers can be controlled in the same way.

FIG. 4 schematically shows a ginning installation 42, which can also be controlled using the method according to the invention. The fiber properties are not determined periodically as in the prior art, but continuously on the material flow.

The raw cotton is unloaded from harvest vehicles 44 into a buffer store 45 and layered there. Here the flakes are homogenized for the first time. In the gin plant, the cotton pneumatically reaches a feed module 28 and is then subjected to a first cleaning process in a sand separator 29. The cotton then passes through a first tower dryer 30 and, after passing through a first diagonal roller cleaner, through a separating machine 31 for larger plant parts. The excess moisture of the fibers is extracted in a second tower dryer 32. A second cross roll cleaner 39 and a blow cleaner 34 remove further foreign matter before the cotton fibers are fed to a cleaner (extractor) 35. Immediately below this is a gin 36. There, primarily plant-based foreign substances such as Grains, fruit capsules etc. removed. The fibers finally reach a fiber fine cleaner 37 (lint cleaner), where the high-quality fiber parts of the cotton plant are further cleaned. The pneumatic onward transport finally leads to a baler 38.

A first sensor 40 is arranged in front of the first tower dryer 30 or possibly already after the buffer store 45 for influencing machine or conveying parameters. A second sensor 41 is in the transition area between the cleaner (extractor) 35 and the gin 36. The two sensors 40 and 41 and, if appropriate, further sensors can be used to control the tower dryer, the ginning machine and the fiber fine cleaner and to remove foreign substances, so that fiber bales 43 of known, as constant as possible quality can be produced.

Claims (24)

1. A method of controlling a treatment installation for textile fibres, in particular cotton fibres, prior to spinning, in which the fibres continuously pass through various treatment stations in succession in one go by means of a transport system and in so doing are in particular at least cleaned and homogenised, characterised in that

   - during transport of the fibres at least two different physical measurement parameters are continuously ascertained at the fibres by a sensor system,

   - an actual value for given material properties is derived from the ascertained measurement parameters in an evaluation device, the actual value being compared to a reference value for each material property, and

   - when there are deviations from a reference value the operating condition of at least one treatment station and/or the transport system is altered.
2. A method according to claim 1 characterised in that at least one of the following properties is ascertained:

   - colour,

   - moisture content,

   - surface coating (stickiness, wax context),

   - temperature,

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

   - fibre fineness,

   - fibre or flock cleanness, and

   - fibre length (staple distribution).
3. A method according to one of claims 1 and 2 characterised in that the presence of foreign substances is ascertained at the sensor system.
4. A method according to claim 3 characterised in that the presence of at least one of the following foreign substances is ascertained:

   - foreign fibres of natural origin,

   - plastic material,

   - vegetable foreign material,

   - metals,

   - mineral foreign material,

   - nits,

   - animal secretions, in particular honeydew, and

   - agricultural additives.
5. A method according to one of claims 1 to 4 characterised in that the sensor system transmits and 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 operates in the near infrared range.
7. A method according to one of claims 1 to 4 characterised in that the sensor system transmits and receives ultrasonic waves.
8. A method according to one of claims 1 to 7 characterised in that the sensor system ascertains the measurement parameters with at least two sensors at positions in the treatment installation, which are different in relation to the transport direction.
9. A method according to one of claims 1 to 8 characterised in that the fibres pass through or go to the treatment stations with a pneumatic transport system.
10. A method according to one of claims 1 to 9 characterised in that the measurement parameters are evaluated or averaged in different time portions.
11. A method according to one of claims 1 to 10 characterised in that it takes place in the processing of raw cotton (ginning) between the operation of feeding in the cotton capsules and the operation of pressing the cleaned cotton fibres to form bales.
12. A method according to one of claims 1 to 10 characterised in that it takes place in processing of cotton fibres in the spinning mill between the operation of opening the cotton bales and the carding operation to form a fibre fleece.
13. A method according to claim 12 characterised in that the fibres

    - are presented in the form of bales and are removed by means of a bale removal machine,

    - pass through a separator,

    - are fed to at least one mixer, and

    - are then processed on at least one card to form a sliver,

    - wherein when foreign substances or material differing greatly from a reference value is detected the separator is activated by way of the evaluation device and when other deviations are detected the mixer is actuated by way of the evaluation device to alter the mixing ratio.
14. A method according to claim 13 characterised in that when other deviations are detected in addition a cleaner and/or a card are actuated for altering the machine parameters.
15. A method according to one of claims 12 to 14 characterised in that when foreign substances and/or other deviations are detected the bale removal machine is actuated to alter the removal movement.
16. Apparatus for controlling a treatment installation for textile fibres, in particular cotton fibres, prior to spinning, comprising a plurality of treatment stations, in particular at least one cleaner and a homogenisation device, and a transport system for continuously transporting the fibres in one go through the treatment stations, characterised by

    - a sensor system with which at least two different physical measurement parameters at the fibres can be detected,

    - an evaluation device with a reference value generator for at least one material property, in which an actual value in respect of said material property can be derived from various measurement parameters, which actual value can be compared to a reference value, and

    - a control device for altering the operating condition of at least one treatment station and/or the transport system when there are deviations of the ascertained actual values from a reference value.
17. Apparatus according to claim 16 characterised in that the sensor system has at least one sensor which transmits and receives electromagnetic waves of different wave spectra.
18. Apparatus according to claim 17 characterised in that at least one sensor is a near infrared sensor.
19. Apparatus according to claim 16 characterised in that the sensor has at least one ultrasonic sensor.
20. Apparatus according to one of claims 16 to 19 characterised in that the sensor system has at least two individual sensors which are arranged at different locations of the treatment station in relation to the transport direction.
21. Apparatus according to one of claims 16 to 20 characterised in that the transport system is a pneumatic transport system and that the sensor system is directly associated with at least one portion of the fibre transport line,
22. Apparatus according to one of claims 16 to 21 characterised in that the treatment installation has as treatment stations in series:

    - a bale removal machine,

    - a separator,

    - a mixer, and

    - a card, and

    - that the separator is actuable by way of the control device upon detection of foreign substances or greatly differing material and the mixer is actuable by way of the control device upon detection of other differing material properties.
23. Apparatus according to claim 22 characterised in that a cleaner and/or the card is additionally actuable.
24. Apparatus according to claim 22 or claim 23 characterised in that the bale removal machine is additionally actuable.