EP3918119B1 - Spinning process optimisation with regard to foreign contamination - Google Patents

Description

AREA OF EXPERTISE

The present invention is in the field of yarn spinning. It relates to a method for optimizing a spinning process with regard to foreign materials and a device for carrying out the method, according to the independent patent claims.

STATE OF THE ART

Foreign materials in the yarn are one of the major problems in modern spinning mills. These are materials that differ from the intended base material of the yarn fibers, e.g. B. cotton fibers distinguish. They can be of different origins, e.g. B. Plastic packaging, cords, human or animal hair, etc. Foreign materials lead to thread breakage in spinning and weaving, accept dye in a different way than the base material and affect the appearance of the textile end product. They significantly reduce the value of the end product. Section 3.8 of the USTER® NEWS BULLETIN NO. 47 "The origins of fabric defects - and ways to reduce them", Uster Technologies AG, March 2010 .

The WO-2006/079426 A1 discloses a method and apparatus for separating foreign matter from fibrous material, particularly raw cotton. Such methods are used, for example, in the blowroom to prepare the raw cotton for spinning. In a pneumatic fiber transport line, the fiber material is guided past a sensor system and a separation device one after the other. When foreign materials are detected by the sensor system, they are removed from the fiber transport line through a removal opening in the fiber transport line by means of a compressed air pulse directed transversely to the fiber transport line. A corresponding product is in the brochure " USTER® JOSSI VISION SHIELD 2 - The key to Total Contamination Control", Uster Technologies AG, October 2015 , described.

Further downstream in the textile manufacturing process, foreign materials can be removed from the yarn on spinning or winding machines by so-called yarn clearers. A yarn clearer includes a measuring head with at least one sensor that scans the moving yarn and thereby detects yarn defects such as foreign materials or thick and thin spots. The sensor's output signal is continuously evaluated according to specified criteria. The US-6,244,030 B1 discloses a yarn clearer that not only detects foreign materials but also distinguishes different types of foreign materials from each other. The sensor scans the yarn optically with reflected light. A binning field or matrix is provided. The length of yarn sections is plotted along the horizontal axis of the classification field and the reflectivity of light on the yarn is plotted along the vertical axis. The classification field is divided into 16 classes for light foreign materials and 16 classes for dark foreign materials. Yarn sections of the same class are counted. A corresponding product is in the brochure " USTER® QUANTUM 3 Application Handbook", Section 8.4, Uster Technologies AG, April 2011 , described.

The WO-2017/190259 A1 describes a method and apparatus for monitoring contamination in a fiber tuft stream. In one embodiment, a first monitor monitors contaminants in a fiber fluff stream while a second monitor monitors contaminants downstream in the textile manufacturing process. The second monitoring device can be a yarn clearer on a winding machine. A control unit is connected to the first and second monitoring devices. It collects data from the two monitors, evaluates them statistically and issues reports produced therefrom to an operator. In a control loop, a limit for removing the impurities in the first monitor is changed depending on a monitoring result of the second monitor.

In the US-4,653,153 A and EP-0'176'661 A2 describe control devices for stretching processes in autoleveling draw frames in the textile industry. They can operate according to the open or closed control loop principle in order to obtain a strip with a uniform cross-section at the outlet of the stretching passage. The measurement signal from a fast-reacting measuring device at the exit of the section is correlated with another measurement signal at the entry to the section. As a result, the parameters that determine the amount of distortion are corrected in such a way that short-term fluctuations in the cross-section of the strip are also compensated for. The transit time of the strip from the actuator to the measuring device at the exit of the draw frame and the overall amplification of the measuring signal are particularly important.

PRESENTATION OF THE INVENTION

It is an object of the present invention to provide a method that optimizes a spinning process with respect to foreign materials. The optimization should relate in particular to the yarn quality and/or the production costs: the yarn quality should be increased with the same production costs, the production costs should be reduced with the same yarn quality, or the yarn quality should be increased and the production costs should be reduced at the same time. In connection with foreign materials, a higher yarn quality means a lower proportion of disruptive foreign materials in the yarn. The production costs are e.g. influenced by the amount of fiber material rejected as waste and the frequency of winder shutdowns.

A further object of the invention is to provide a device for carrying out the method.

This and other objects are achieved by the method according to the invention and the device according to the invention, as defined in the independent patent claims. Advantageous embodiments are specified in the dependent patent claims.

The invention is based on the idea of associating foreign material information that was determined at two different points in the spinning process with one another and making a change to the spinning process on the basis of the foreign material information that is associated with one another. The allocation must be made in such a way that the foreign material information essentially relates to the same sample of the fiber material.

In this document, the expression “sample” refers to an associated quantity of the fiber material which essentially has the same, essentially homogeneously distributed properties. The size of the sample can range from a flock of fibers with a mass of less than 1 g to several tons of fiber material. An example of a sample is a presentation of 50 cotton bales of 220 kg each (total 11 1), as found in an opening shop. The sample goes through the spinning process; their structure and shape change depending on the respective process step. For example, the same sample can B. take the form of raw fibers, fiber flock, batt, sliver, roving or yarn. The sample can be divided into different processing machines during the spinning process.

The method according to the invention serves to optimize a spinning process, which is run through by a fiber material fed in in the form of raw fibers and output in the form of yarn, with regard to foreign materials in the fiber material. At a first point in the spinning process, first foreign material information relating to the foreign materials is ascertained. At a second point in the spinning process, which is downstream of the first point, second foreign material information relating to the foreign materials is determined. The first position or the second position corresponds to a process step from the following set: opening, coarse cleaning, mixing, fine cleaning, carding, doubling, combing, stretching, spinning, rewinding. The first piece of foreign material information and the second piece of foreign material information are associated with one another in such a way that they relate to the same sample of the fiber material. A change is made to the spinning process on the basis of the first piece of foreign material information and the second piece of foreign material information assigned to it.

The first foreign material information and the second foreign material information can be determined on the entire sample of the fiber material or on a subset of the sample of the fiber material. It can take place continuously or at discrete points in time. It can be done online in the spinning process or offline by taking the sample of the fiber material or a portion thereof from the spinning process and using it outside of the spinning process, e.g. B. in a textile laboratory is examined.

The change to the spinning process may involve a change in the raw fibers fed into the spinning process, or at least part thereof, and/or a change in settings on machines involved in the spinning process.

The mutual assignment of the first foreign material information and the second foreign material information preferably includes one of the following steps: determining a throughput time as that time interval during which a fiber runs from the first point to the second point in the spinning process; determining a property of the sample itself; and labeling a carrier of the sample. The throughput time can be determined empirically or theoretically from known processing and storage times. As a property of the sample z. B. their chemical composition can be used, whereby the natural composition of the fiber by means of genetic analysis and / or an artificially added label (marker) can play a role. Depending on the nature of the sample, the carrier of the sample can be cans or coil cores on which optical and/or electromagnetic markings are applied.

In a preferred embodiment, at the first point in the spinning process, a flow of fiber tufts, which are pneumatically conveyed in an air current, is monitored for foreign materials. The first piece of foreign material information is determined on the basis of the monitoring. At the second point in the spinning process, yarn that has been spun from the fiber tufts and is conveyed along its length is monitored for foreign materials. The second piece of foreign material information is determined on the basis of the monitoring. A transit time is defined as the time interval during which a fiber travels from the first point to the second point in the spinning process. The first foreign material information is at a first point in time and the second foreign material information is determined at a second point in time, which is after the first point in time by the throughput time. The first item of foreign material determined in this way and the second item of foreign material determined in this way are assigned to one another.

In one embodiment, the first foreign matter information is a first foreign matter rate indicating a rate of foreign matter in the fiber flock, and the second foreign matter information is a second foreign matter rate indicating a rate of foreign matter in the yarn. Preferably, the first foreign material level substantially indicates a number of foreign materials per unit mass of fiber flock or per unit time, and/or the second foreign material level substantially indicates a number of foreign materials per unit mass of yarn, per unit length of yarn or per unit time.

In one embodiment, at the first point in the spinning process, foreign materials are separated from the flow of fiber tufts according to a separation criterion, and the change to the spinning process involves a change in the separation criterion. The first foreign matter information may be a rejection rate indicating a number of rejection per unit mass of fiber floc or per unit time. A relationship between the separation criterion and the separation rate is advantageously determined beforehand, and this relationship is taken into account when the spinning process is changed.

In one embodiment, at the second point in the spinning process, foreign materials detected in the yarn are cleaned out of the yarn according to a cleaning criterion, and the change to the spinning process includes a change in the cleaning criterion. Preferably, the second foreign matter information is a cleaning rate indicating a number of cleaning operations per unit mass of yarn, per unit length of yarn, or per unit time. A connection between the cleaning criterion and the cleaning rate can be determined beforehand and this connection can be taken into account when changing the spinning process. Costs for an elimination can be determined in advance and when changing the spinning process a product of the cost of an elimination and the elimination rate. Costs for a cleaning process can be determined beforehand and a product of the costs for a cleaning process and the cleaning rate can be taken into account when changing the spinning process. It may be advantageous to consider a linear combination of the product of the cost of a rejection and the rejection rate and the product of the cost of a cleaning operation and the cleaning rate when changing the spinning process. The change to the spinning process is advantageously made in such a way that the linear combination takes on a smaller value after the change than before the change, and preferably in such a way that a global minimum of the linear combination is reached.

The throughput time can be entered manually by an operator, calculated automatically on the basis of specifications and/or retrieved from a database on the basis of specifications.

In one embodiment, first classes of foreign materials in the fiber material are predetermined at the first location, which first classes differ from one another with regard to properties of the foreign materials, and the first foreign material information relates to one or more of these first classes. Likewise, second classes of foreign materials in the fiber material can be predetermined at the second location, which second classes differ from one another with regard to properties of the foreign materials, and the second foreign material information can relate to one or more of these second classes.

In one embodiment, the first foreign material information and the second foreign material information are issued to an operator at the same time. The simultaneous output of the first foreign material information and the second foreign material information can be at least partially graphical. In addition to the simultaneous output of the first item of foreign material and the second item of foreign material, an evaluation of the first item of foreign material and/or the second item of foreign material can be output to the operator. The evaluation preferably includes at least two categories that indicate appropriate or critical foreign material information. In addition to the simultaneous output of the first foreign material information and the second foreign material information, a recommendation for the change in the spinning process can be output to the operator.

In one embodiment, an alarm is issued to an operator on the basis of the first piece of foreign material information and the second piece of foreign material information associated therewith. Preferably, a time profile of the first piece of foreign material information and a time profile of the second piece of foreign material information assigned to it are determined, and the alarm is output on the basis of the time profiles.

In one embodiment, the operator makes the change to the spinning process on the basis of the simultaneously output first piece of foreign material information and second piece of foreign material information, on the basis of the evaluation and/or on the basis of the recommendation.

In one embodiment, the change to the spinning process is made automatically.

In one embodiment, a worldwide frequency distribution of a foreign material content in fiber flocks and/or in yarns is determined beforehand, and this frequency distribution is taken into account when changing the spinning process.

The invention also relates to a device for carrying out the method according to the invention in a spinning mill carrying out a spinning process which is run through by a fiber material fed in in the form of raw fibers and output in the form of yarn. The device includes a first monitoring device at a first point in the spinning process. The first monitoring device is set up to determine first foreign material information relating to the foreign material. The apparatus further includes a second monitoring device at a second location in the spinning process, downstream of the first location. The second monitoring device is set up to provide a second monitoring device relating to the foreign materials determine foreign material information. The first position or the second position corresponds to a process step from the following set: opening, coarse cleaning, mixing, fine cleaning, carding, doubling, combing, stretching, spinning, rewinding. The device also includes a central control device connected to the first monitoring device and the second monitoring device. The central control device is set up to assign the first piece of foreign material information and the second piece of foreign material information to one another and to automatically make a change to the spinning process on the basis of the first piece of foreign material information and the second piece of foreign material information assigned to it.

In one embodiment, the central control device is set up to simultaneously output the first item of foreign material information and the second item of foreign material information to an operator.

In one embodiment, the apparatus includes a fiber tuft monitor at the first point in the spinning process. The fiber tuft monitoring device is set up to monitor a stream of fiber tufts, which are conveyed pneumatically in an air stream, for foreign materials and to determine the first item of foreign material information on the basis of the monitoring. The device also includes a yarn monitoring device at the second point in the spinning process. The yarn monitoring device is set up to monitor yarn that has been spun from the fiber tufts and is conveyed along its longitudinal direction for foreign materials and to determine the second piece of foreign material information on the basis of the monitoring. The central control device is set up to store a throughput time as the time interval during which a fiber runs through from the first point to the second point in the spinning process, the first foreign material information at a first point in time and the second foreign material information at a second point in time, which is around the throughput time is after the first point in time, to store and to assign the first foreign material information determined in this way and the second foreign material information determined in this way to one another.

Thanks to the invention, the spinning process is optimized with regard to foreign materials. A high yarn quality is achieved because few foreign substances remain in the yarn. At the same time, productivity is high because little fiber material is discarded as waste.

LISTING OF DRAWINGS

Figur 1

zeigt schematisch einen Teil eines Spinnprozesses in einer Spinnerei und eine erfindungsgemässe Vorrichtung.

Figur 2

zeigt ein beispielhaftes Faserereignisfeld für Fremdmaterialereignisse in einem Strom von Faserflocken.

Figur 3

zeigt ein beispielhaftes Garnereignisfeld für Fremdmaterialereignisse in einem Garn.

Figuren 4 und 5

zeigen Beispiele für grafische Ausgaben von einander zugeordneten Fremdmaterialinformationen.

Figur 6

zeigt ein Diagramm, anhand dessen Grenzen von Bewertungsbereichen für Fremdmaterialinformationen festgelegt werden können.

Figur 7

zeigt drei Beispiele für Zeitverläufe von einander zugeordneten Fremdmaterialinformationen.

Figur 8

zeigt Diagramme zur Minimierung der Kosten in einem Spinnprozess.

The invention is explained in detail below with reference to the drawings. A preferred embodiment is mainly discussed in which the first point in the spinning process corresponds to the fine cleaning of fiber tufts and the second point in the spinning process corresponds to the rewinding of yarn. However, this should not restrict the generality of the invention. Alternatively, the first and/or second location may correspond to other process steps.

figure 1

shows schematically part of a spinning process in a spinning mill and a device according to the invention.

figure 2

Figure 12 shows an example fiber event field for foreign material events in a stream of fiber tufts.

figure 3

Figure 12 shows an example yarn event field for foreign material events in a yarn.

Figures 4 and 5

show examples of graphical outputs of foreign material information assigned to one another.

figure 6

shows a diagram that can be used to define the limits of assessment areas for foreign material information.

figure 7

shows three examples of time courses of foreign material information associated with one another.

figure 8

shows diagrams for minimizing costs in a spinning process.

CARRYING OUT THE INVENTION

figure 1 shows schematically a part of a spinning process 1, which takes place in a spinning mill. In the spinning process 1 z. B. yarn spun from raw cotton. The spinning process 1 can e.g. B. include the following process steps: opening, coarse cleaning, mixing, fine cleaning 11, carding 12, doubling, combing, stretching, spinning 13, rewinding 14. Not all process steps 11-14 mentioned need to be run through, and further process steps can be added. For the sake of simplicity, in figure 1 only a few process steps 11-14 are shown schematically, while others are indicated by dots.

In figure 1 a device 2 according to the invention is also shown schematically. At a first location at an early stage in the spinning process 1, e.g. B. in or immediately after the fine cleaning 11, there is a stream of fiber flocks, which are pneumatically conveyed in an air stream. A fiber tuft monitoring device 3 of the device 2 according to the invention is located at this first point. The fiber tuft monitoring device 3 is set up to monitor the flow of fiber tufts for foreign materials and to determine first foreign material information relating to the foreign materials on the basis of the monitoring.

The first foreign matter information may be a first foreign matter rate indicating a rate of foreign matter in the fiber tufts. This can e.g. B. essentially a number of foreign materials per unit mass of fiber floc (e.g. per 100 kg) or per unit time (e.g. per hour); the two figures can be converted into one another using the commonly known mass flow per unit of time (e.g. in kg/h).

In addition, the fiber tuft monitoring device 3 can separate foreign materials from the stream of fiber tufts according to a separation criterion. A method and a device for separating foreign matter in fiber material, particularly in raw cotton, are per se z. B. from the WO-2006/079426 A1 known. In a preferred embodiment, the fiber tuft monitoring device 3 includes a sensor system that detects properties of objects, including foreign matter, in the flow of fiber tufts. The sensor system can e.g. B. include two CCD cameras that take pictures of the flow of fiber flocks; other or additional sensors are possible. The sensor system is connected to a control unit, for example a computer. The control unit evaluates an output signal from the sensor system and uses a rejection criterion in order to decide whether an object detected in the flow of fiber tufts is permissible or not. Depending on the result of the evaluation, it controls a separation unit Separation of foreign materials from the flow of fiber tufts. The separation unit includes z. B. a plurality of compressed air nozzles that can be actuated individually by a control unit. If the control unit detects an impermissible object, it causes the compressed air nozzle located at the location of the object to eject compressed air perpendicularly to the transport direction of the flow of fiber tufts, so that the object is separated from the flow of fiber tufts.

figure 2 Figure 12 shows a fiber event field 20 for fiber events that includes a quadrant or part of a quadrant of a two-dimensional Cartesian coordinate system. Along a first axis, 21, e.g. the abscissa, a first parameter is plotted and plotted along a second axis 22, e.g. B. the ordinate, a second parameter is recorded. The first parameter may relate to a geometric property of the objects in the stream of fiber tufts and is preferably a length or an area of the objects. The second parameter may relate to an optical property of the objects and is preferably an intensity of light reflected from, transmitted through or absorbed by the flakes. The values of the first and second parameters determined for an object define coordinates of a fiber event representing the object in the fiber event field 20. In figure 2 only one fiber event is shown as point 23 by way of example; in practice, there are many such fiber events in a flow of fiber tufts, the locations of which in the fiber event field 20 generally differ from one another.

The fiber event field 20 of figure 2 is divided into 20 rectangular first classes 27. In at least one, and preferably in all, of the first classes 27, the fiber events can be counted and their respective number can thus be determined. A relative proportion of the fiber events in the respective first class 27 is determined by forming a ratio of the absolute number of fiber events in the respective first class 27 and a total number of fiber events in the entire fiber event field 20 . The first foreign material portion can relate to only one or only some of the first classes 27 .

figure 2 also illustrates a possible separation criterion for foreign materials in a flow of fiber flocks. The elimination criterion can e.g. B. in the form of a Elimination curve 26 may be specified in the fiber event field 20, as in FIG WO-2017/190259 A1 described. The rejection curve 26 divides the fiber event field 20 into two mutually complementary regions: a first region 24 in which allowable fiber events reside, and a second region 25 in which invalid fiber events reside. Objects represented by fiber events in the first region 24 remain in the stream of fiber tufts, while objects represented by fiber events in the second region 25 are discarded from the stream of fiber tufts.

The elimination curve 26 in the two-dimensional fiber event field 20, as shown in FIG figure 2 shown is only one possible exclusion criterion for use in the present invention. In one embodiment, the elimination criterion may only consider a single parameter, e.g. B. an intensity as plotted along the ordinate 22 of the fiber event field 20. In another embodiment, the elimination criterion may consider more than two parameters, e.g. B. a geometric property and an intensity as they are plotted along the axes 21, 22 of the fiber event field 20, and additionally a color of the object.

The elimination criterion can be specified by an operator, taken from a database or calculated automatically.

The first foreign matter information may be a rejection rate. This can e.g. B. indicate essentially a number of excretions per unit mass of fiber flocks (e.g. per 100 kg) or per unit of time (e.g. per hour); the two figures can be converted into one another using the commonly known mass flow per unit of time (e.g. in kg/h).

At a second point in the spinning process 1 (see figure 1 ) located downstream of the first location, yarn spun from the fiber tufts is conveyed along its longitudinal direction, e.g. B. during rewinding 14. A yarn monitoring device 4 of the device 2 according to the invention is located at this second point. The yarn monitoring device 4 is set up to check the yarn for foreign materials to monitor and, based on the monitoring, to determine second foreign material information relating to the foreign materials.

The second foreign matter information may be a second foreign matter rate indicating a rate of foreign matter in the yarn. This can e.g. B. essentially a number of foreign materials per unit mass of yarn (e.g. per kg), per unit length of yarn (e.g. per 100 km) or per unit time (e.g. per hour); the three specifications can be converted into one another using the yarn number (e.g. in tex = g/km) or the winding speed (e.g. in m/min).

The yarn monitoring device 4 can, for. B. be designed as a yarn cleaner system. Yarn cleaners for monitoring a running yarn for foreign materials are known per se, e.g. B. from the US-6,244,030 B1 . Accordingly, the yarn monitoring device 4 includes a sensor that acquires measured values of an optical measurement on a yarn section along the longitudinal direction of the yarn. It also contains an evaluation unit for determining values of a reflectivity of the yarn section measured from the measured values. The evaluation unit provides a classification field for foreign materials, which is divided into at least two classes. It classifies the yarn events into at least two classes and determines the shares of yarn events in at least one of the at least two classes in a total number of foreign materials detected in the yarn.

Two event fields for yarn events are defined in paragraph 8.4 of the " USTER® QUANTUM 3 Application Handbook", Uster Technologies AG, April 2011 , stated. One of them is an example in the present figure 3 played back. The yarn event field 30 includes a quadrant or part of a quadrant of a two-dimensional Cartesian coordinate system. An abscissa 31 of the coordinate system indicates an extension of reflectivity values in the longitudinal direction, e.g. B. in centimeters. An ordinate 32 indicates a deviation of reflectivity values from a target value, e.g. B. Percentage. The values for the extent and the deviation of the reflectivity values determined for a yarn event define coordinates of the yarn event in the yarn event field 30. In figure 3 is just a yarn event as point 33 drawn in; in practice there are many such events in a yarn whose locations in the yarn event field 30 differ from each other.

The yarn event field 30 from figure 3 is divided into 32 rectangular second classes, uniquely identified with letters and numbers AA1-F. A second class AA1-F can be clearly assigned to each yarn event in the yarn event field 30 according to its position. The yarn event represented by point 33 is in the second class C3. In at least one, and preferably in all, of the second classes AA1-F, the yarn events can be counted and their respective number can thus be determined. A relative proportion of the yarn events in the respective second class AA1-F is determined by forming a ratio of the absolute number of yarn events in the respective second class AA1-F and a total number of yarn events in the entire yarn event field 30 . The second foreign material portion can relate to only one or only some of the second classes AA1-F.

A cleaning curve 36 is also plotted in the yarn event field 30, which represents a cleaning limit as the boundary between permissible and impermissible foreign materials in the yarn. The determined coordinates of yarn events are compared to the clearing boundary 36 and the yarn events are removed from the yarn depending on the comparison, i. H. cleaned up or not.

The second foreign matter information may be a cleaning rate. This can e.g. B. essentially indicate a number of cleaning processes per unit mass of yarn (e.g. per kg), per unit length of yarn (e.g. per 100 km) or per unit of time (e.g. per hour); the three specifications can be converted into one another using the yarn number (e.g. in tex = g/km) or the winding speed (e.g. in m/min).

In the embodiment according to figure 1 the yarn monitoring device 4 is bidirectionally connected to a central control device 5, which is represented by an arrow 7. The central control device 5 is bidirectionally connected to the fiber tuft monitoring device 3 , which is represented by an arrow 6 .

The data connections 6, 7 enable a bidirectional exchange of data between the devices 3, 4, 5 involved data equipped. The data connections 6, 7 can be wired or wireless.

The central control device 5 can be implemented as a stand-alone device, e.g. B. as a computer that is in the spinning mill or outside the spinning mill. In this case, it contains appropriate receiving and transmitting means for receiving or transmitting data. Alternatively, the central control device 5 can be integrated in another device, e.g. B. in a yarn testing device in the textile laboratory of the spinning mill, in the fiber tufts monitoring device 3, in the yarn monitoring device 4, etc. In the latter two cases, there can be a direct data connection between the yarn monitoring device 4 and the fiber tufts monitoring device 3, via which the two devices 4, 3 transmit data or exchange.

Further devices (not shown) can be located along the connection 6 and/or 7, which receive the transmitted data, process them if necessary and send them on. In one embodiment, several fiber tuft monitors 3 are connected to a fiber tuft expert system. The fiber tuft expert system is set up to receive data from the fiber tuft monitoring devices 3 , to process them and to output them in a suitable form, and to control the fiber tuft monitoring devices 3 . It is in turn connected to the central control device 5 . In one embodiment, multiple yarn monitors 4 are connected to a yarn expert system. The yarn expert system is set up to receive data from the yarn monitoring devices 4, to process them and output them in a suitable form, and to control the yarn monitoring devices 4. It is in turn connected to the central control device 5 .

In the spinning process 1 of figure 1 a throughput time Δt (cf. Figures 7(b) and (c) ) certainly. In this document, the throughput time Δt is defined as the time interval during which a fiber passes through the spinning process 1 from the first point (e.g. fine cleaning 11) to the second point (e.g. rewinding 14). The throughput time Δt depends on a number of factors, e.g. B. the spinning process 1, the organization of the spinning mill, the raw fibers, the yarn to be produced, etc. It can be in the range of hours or days, depending on the situation. In one embodiment, the throughput time Δt can be entered manually into the central control device 5 by an operator. In another embodiment, the throughput time Δt can be calculated automatically by the central control device 5 . The calculation can e.g. B. based on data stored in the central control device 5, z. B. the spinning process 1, the organization of the spinning mill, the raw fibers, the yarn to be produced, etc., take place. In a further embodiment, the throughput time Δt can be called up by the central control device 5 using inputs from a database. It can remain constant or be changed while the method according to the invention is being carried out, in which case a change can again be made manually or automatically.

In the method according to the invention, the first proportion of foreign material and the second proportion of foreign material relate to the same sample of fiber material, ie they are determined “for the same fibers”, so to speak. For this purpose, a second point in time t ₂ (cf. Figures 7(b) and (c) ) at which the second proportion of foreign material is determined by the throughput time Δt after a first point in time ti at which the first proportion of foreign material is determined, ie t ₂ =ti+Δt. The first proportion of foreign material determined in this way and the second proportion of foreign material determined in this way are assigned to one another.

Determining the throughput time Δt is only one of several possibilities for mutual assignment of the first item of foreign material information and the second item of foreign material information. Another possibility is to determine a property of the sample itself. As a property of the sample z. B. their chemical composition can be used, whereby the natural composition of the fiber by means of genetic analysis and / or an artificially added label (marker) can play a role. A further possibility for assignment consists in marking a carrier of the sample in order to track the sample in the spinning process. carrier of the sample can, depending on the nature of the sample, be cans or coil cores on which optical and/or electromagnetic markings are applied.

• In einer Ausführungsform beinhaltet die Änderung an dem Spinnprozess 1 eine Änderung des Ausscheidungskriteriums. Zu diesem Zweck kann z. B. die Ausscheidungskurve 26 (vgl. Figur 2) geändert werden.
• In einer Ausführungsform beinhaltet die Änderung an dem Spinnprozess 1 eine Änderung des Reinigungskriteriums. Zu diesem Zweck kann z. B. die Reinigungskurve 36 (vgl. Figur 3) geändert werden.
• In einer Ausführungsform beinhaltet die Änderung an dem Spinnprozess 1 eine Änderung der in den Spinnprozess 1 eingespeisten Rohfasern oder zumindest eines Teils davon.
• In einer Ausführungsform beinhaltet die die Änderung an dem Spinnprozess 1 eine Änderung von Einstellungen an Maschinen, die an dem Spinnprozess 1 beteiligt sind.

A change is made to the spinning process 1 on the basis of the first portion of foreign material and the second portion of foreign material assigned to it. Below are some examples of such changes:

• In one embodiment, the change to the spinning process 1 includes a change in the elimination criteria. For this purpose z. B. the elimination curve 26 (cf. figure 2 ) can be changed.
• In one embodiment, the change to the spinning process 1 involves a change in the cleaning criterion. For this purpose z. B. the cleaning curve 36 (cf. figure 3 ) can be changed.
• In one embodiment, the change to the spinning process 1 involves a change in the raw fibers fed into the spinning process 1, or at least a part thereof.
• In one embodiment, the change to the spinning process 1 includes changing settings on machines involved in the spinning process 1 .

In one embodiment of the method according to the invention, the first piece of foreign material information and the second piece of foreign material information are output to an operator at the same time. The first and second pieces of foreign material information are preferably output graphically at the same time. The Figures 4 and 5 show two examples thereof, where the first foreign material information is the elimination rate and the second foreign material information is the cleaning rate.

figure 4 shows a first example of a graphical output 40. It contains a column 41 which is divided into four evaluation areas 42-45. On both sides of the column 41 there are horizontal arrows 46, 47 whose position relative to the column 41 can be changed in the vertical direction. The left arrow 46 shows the excretion rate, the right arrow 47 the associated cleaning rate. The further down an arrow 46, 47 is, the lower the relevant rate, and vice versa. For the purpose of evaluating the rates, the four evaluation areas 42-45 of column 41 in the traffic light colors green for appropriate (second evaluation area 43), yellow for critical (first evaluation area 42 and third evaluation area 44) and red for highly critical (fourth evaluation area 45). In the example of figure 4 the elimination rate is low and the purification rate is very high. Such a disparity in rates is not optimal. In addition to the simultaneous output of the rejection rate and the cleaning rate, a recommendation for the change in the spinning process can be output to the operator. Such a recommendation is shown in figure 4 the two simple, vertical arrows 48, 49 indicate: The excretion rate should be increased (arrow 48) and the purification rate decreased (arrow 49). In the case of an optimal setting, both horizontal arrows 46, 47 point to the second, green evaluation area 43. B. a separate column for the excretion rate and for the purification rate.

figure 5 shows a second example of a graphical output of the rejection rate and the purification rate. This is a portfolio diagram 50. The excretion rate is plotted along an abscissa 51, and the purification rate is plotted along an ordinate 52. The elimination rate and the associated purification rate each form the coordinates of a point 53 in the portfolio diagram. Five evaluation areas 54-58, which correspond to different evaluation categories or recommendation categories, are shown schematically in the diagram area. The evaluation ranges 54-58 can be different than those in figure 5 have drawn forms. For the purpose of evaluating the rates, the five evaluation areas 54-58 can be used in the traffic light colors green for appropriate (first evaluation area 54 and fifth evaluation area 58), yellow for critical (second evaluation area 55 and fourth evaluation area 57) and red for highly critical (third evaluation area 56). be colored. The drawn point 53 lies in a first, green evaluation area 54. In this case, good raw fibers with little foreign material are obviously used, so that there is no need for action. A point lying in a second, yellow evaluation area 55 would indicate a high elimination rate combined with a low cleaning rate. Such a mismatch in rates should be balanced by reducing the rate of elimination and increasing the rate of purification. This recommendation to the operator is indicated by an arrow 59. In a third, red evaluation area 56 are both the elimination rate and the cleaning rate high, resulting in poor productivity. In this case, consideration should be given to using better, less contaminated crude fiber. A point lying in a fourth, yellow evaluation area 57 would indicate a low elimination rate combined with a high cleaning rate. This corresponds to the figure 4 depicted situation. Such mismatch in rates should be balanced by increasing the rate of elimination and decreasing the rate of purification. This recommendation to the operator is indicated by an arrow 59. If a point is in the fifth, green evaluation area 58, then the rejection rate and the cleaning rate are balanced and the spinning process 1 does not need to be changed.

In the examples of Figures 4 and 5 the value of the elimination rate and/or the purification rate can be given in addition to the graphic representation. this is in figure 4 the case where the two values are entered in the respective horizontal arrows 46,47. Alternatively, only the values without a graphical representation can be output to the operator.

Instead of with or in addition to arrows 48, 49 ( figure 4 ) or 59 ( figure 5 ) or similar graphic symbols, the recommendation can be given in words to the operator.

In the highly critical cases (fourth assessment range 45 from figure 4 and third evaluation area 56 of figure 5 ) preferably not only a recommendation but also a warning or an alarm is issued to the operator. This can be done graphically or in words on a display unit of the central control unit 5 ( figure 1 ), acoustically and/or visually, e.g. B. with a warning light done.

Based on the graphic output, the recommendation and/or the alarm, the operator can make a change to the spinning process 1 manually. Alternatively, the change to the spinning process 1 can be made automatically, e.g. B. from the central control unit 5 ( figure 1 ).

The boundaries of the evaluation areas 42-45, 54-58 in the Figures 4 and 5 can be set in different ways. A first possibility is a requirement based on of experiences. A second possibility is to determine beforehand a worldwide frequency distribution of a foreign material content in fiber tufts and/or yarns and to take this frequency distribution into account when defining the limits of the assessment areas. Such a worldwide frequency distribution can e.g. B. the USTER ^® STATISTICS . The USTER ^® STATISTICS are a compilation of textile quality data, published by the applicant of the present property right, which was determined from the worldwide production of textile raw materials, intermediate products and end products; see https://www.uster.com/en/service/uster-statistics/, retrieved at the time this property right was registered.

Another way to set the boundaries of the rating ranges 42-45, 54-58 in the Figures 4 and 5 is in figure 6 illustrated. The figure shows a diagram 60 in a Cartesian coordinate system, along whose abscissa 61 a parameter influencing the elimination criterion is plotted. This parameter can e.g. B. a sensitivity of the fiber flock monitoring device 3 ( figure 1 ) with respect to the light intensity, which determines the position of the excretion curve 26 ( figure 2 ) determined in the vertical direction. The excretion rate is plotted along the ordinate 62 . A curve 63 indicates the relationship between the sensitivity and the excretion rate. Such a connection can be determined heuristically or theoretically in advance. The abscissa 61 is divided into three areas 64-66. In a first area 64, the sensitivities are so low that they hardly have any effect on the excretion rate. In a third area 66, the sensitivities are very high, resulting in very high elimination rates. In a second range 65 there are medium sensitivities with medium elimination rates. A region 67 of the elimination rate corresponding to this second region 65 corresponds to the appropriate, green region 43 of the elimination rate in figure 4 . Similarly, an appropriate range for the cleaning rate can be set.

figure 7 shows three examples of time courses of the first foreign material information and the second foreign material information assigned to it. These two items of foreign material information are each shown in two diagrams 701, 702 arranged one above the other, with the upper diagram 701 being plotted along an ordinate 72, e.g. Legs Excretion rate E(t) and the lower diagram 702 along an ordinate 73 indicates a second foreign material fraction F(t) and the abscissa 71 is the time axis t common to the two diagrams 701, 702. A first curve 74 in the upper diagram 701 indicates the time course of the first foreign material information, a second curve 75 in the lower diagram 702 indicates the time course of the second foreign material information. It is assumed that no other changes are made to the spinning process 1 apart from a possible change in the elimination criterion. The examples show the expected behavior in each case. A deviation from this behavior indicates an error in the spinning process 1 and can e.g. B. trigger an alarm to the operator.

In Figure 7(a) shows the trivial case in which the elimination rate E(t) remains constant over time and the elimination criterion is not changed. In this case, the second foreign material component F(t) should also remain constant over time; otherwise an alarm should be issued.

In the example of Figure 7(b) a higher elimination rate E(t) is observed at a first point in time ti, without the elimination criterion having been changed. This can be the case when raw fibers are fed into the spinning process 1 with more foreign materials. It is expected that at a second point in time t ₂ , which is later by the throughput time Δt than the first point in time ti, the second proportion of foreign material F(t) will also increase. Conversely, without changing the separation criterion, a fall in the separation rate E(t) should also result in a fall in the second proportion of foreign material F(t).

In the example of Figure 7(c) the elimination criterion is changed at a first point in time ti in such a way that a higher elimination rate E(t) results. As expected, this should have the result that at a second point in time t ₂ , which is later than the first point in time t 1 by the throughput time Δt, the second proportion of foreign material F(t) falls. If, on the other hand, the separation criterion is changed in such a way that a lower separation rate E(t) results, then the second foreign material fraction F(t) should increase later by the throughput time Δt.

figure 8 illustrates a further embodiment of the method according to the invention. In this embodiment, costs are taken into account.

wobei darauf zu achten ist, dass sich in dieser Linearkombination die Ausscheidungsrate E und der Reinigungsrate C auf dieselbe Einheitsmasse beziehen. Die Bedingung zur Minimierung der Gesamtkosten K(E) lautet $$\frac{\mathit{dK}}{\mathit{dE}}=K_E+\frac{d}{\mathit{dE}}C\left(E\right)\cdot K_C=0.$$

Figure 8(a) shows a diagram 801 in a Cartesian coordinate system, along whose abscissa 81 the precipitation rate E is plotted and along whose ordinate 82 the cleaning rate C(E) is plotted. A curve 83 schematically shows a possible connection between the elimination rate E and the purification rate C(E). Such a relationship C(E) can be determined heuristically or theoretically. The costs K _E for an elimination and the costs K _C for a cleaning process can also be determined heuristically or theoretically. The total costs K per unit mass for the precipitations and purification processes in the spinning process 1 are then $$K\left(E\right)=E\cdot K_E+C\left(E\right)\cdot K_C,$$

It should be noted that in this linear combination the excretion rate E and the purification rate C refer to the same unit mass. The condition for minimizing the total cost K(E) is $$\frac{\mathit{dK}}{\mathit{dE}}=K_E+\frac{\mathrm{i.e}}{\mathit{dE}}C\left(E\right)\cdot K_C=0.$$

It follows $$\frac{\mathrm{i.e}}{\mathit{dE}}C\left(E\right)=-\frac{K_E}{K_C}.$$

Accordingly, in a diagram 802 in Figure 8(b) along an ordinate 84 the derivative dC(E)/dE of the curve 83 of Figure 8(a) applied. A curve 85 shows the course of the derivation. A value -K _E /K _C is drawn in as an example, which the derivative assumes at two points E _max , E _min .

In a chart 803 in Figure 8(c) Finally, the total costs K(E) are plotted using a curve 87. At a first point E _max of the two points mentioned is a maximum of the total costs K(E) that is to be avoided. In a second place E _min der On the other hand, the two points mentioned are the minimum that is of interest here. This value E _min should be aimed at by selecting the elimination criterion accordingly, in order to optimize the spinning process 1. In this embodiment, the change to the spinning process 1 should therefore consist in selecting the elimination criterion in such a way that the elimination rate is just E _min ; then the total cost K(E) is minimal. The change can be manual by an operator or automatically, e.g. B. from the central control unit 5 ( figure 1 ) are made.

berechnen. Die Minimalbedingung für den gegebenen Spinnprozess 1 lautet dann $$\frac{d}{\mathit{dE}}C\left(E\right)=-\frac{1}{p}\cdot \frac{K_E}{K_C},$$

worin dC(E)/dE die in Figur 8(b) dargestellte Ableitung der bekannten Funktion C(E) ist.The based on figure 8 The embodiment of the method according to the invention described can be carried out even if the Figure 8(a) shown function for a given spinning process 1 can not be determined or not completely. It suffices if for the given spinning process 1 a single point (E,C') and the function C(E) are known for another but similar spinning process. Assuming that the courses of the curve 83 are similar for both spinning processes, a proportionality factor can be used $$p=\frac{C\prime \left(E\right)}{C\left(E\right)}$$

calculate. The minimum condition for the given spinning process 1 is then $$\frac{\mathrm{i.e}}{\mathit{dE}}C\left(E\right)=-\frac{1}{p}\cdot \frac{K_E}{K_C},$$

where dC(E)/dE are the in Figure 8(b) shown derivative of the known function C(E).

Of course, the present invention is not limited to the embodiments discussed above. In particular, foreign material information relating to the foreign materials can be determined at more than two points in the spinning process. With knowledge of the invention, the person skilled in the art will be able to derive further variants which also belong to the subject matter of the present invention.

REFERENCE LIST

1

spinning process

11

fine cleaning

12

carding

13

spinning

14

rewind

2

contraption

3

fiber tuft monitoring device

4

yarn monitoring device

5

central controller

6, 7

data connections

20

fiber event field

21

abscissa

22

ordinate

23

fiber event

24

first area for allowable fiber events

25

second area for illegal fiber events

26

Elimination curve, elimination criterion

27

Classes of fiber events

30

yarn event field

31

abscissa

32

ordinate

33

yarn event

40

graphical output

41

pillar

42-45

rating areas

46

Arrow indicating elimination rate

47

Arrow indicating cleaning rate

48, 49

Arrows to show recommendations

50

Portfolio Chart

51

abscissa

52

ordinate

53

Point in portfolio chart

54-58

rating areas

59

Arrows to show recommendations

60

diagram

61

abscissa

62

ordinate

63

Curve

64-66

areas on the abscissa

67

area on the ordinate

701, 702

charts

71

abscissa

72, 73

ordinates

74, 75

first or second curve

801-803

charts

81

abscissa

82, 84, 86

ordinates

83, 85, 87

curves

Claims (26)

1. Method for optimizing a spinning process (1), through which a fiber material fed in the form of raw fibers and output in the form of yarn passes, with respect to foreign materials in the fiber material, wherein

   at a first position (11) in the spinning process (1), first foreign material information relating to the foreign materials is determined, and

   at a second position (14) in the spinning process (1), which is located downstream with respect to the first position (11), a second foreign material information relating to the foreign materials is determined,

   wherein the first position (11) and the second position (14), respectively, correspond in each case to a process step from the following set: opening, coarse cleaning, blending, fine cleaning (11), carding (12), doubling, combing, drafting, spinning (13), rewinding (14),

   characterized in that

   the first foreign material information and the second foreign material information are assigned to each other such that they relate to the same sample of the fiber material, and

   a change is made to the spinning process (1) on the basis of the first foreign material information and the second foreign material information assigned thereto.
2. Method according to claim 1, wherein the determination of the first foreign material information and the second foreign material information is performed on the entire sample of the fiber material or on a subset of the sample of the fiber material.
3. Method according to one of the preceding claims, wherein the determination of the first foreign material information and the second foreign material information is performed continuously or at discrete points in time.
4. Method according to one of the preceding claims, wherein the determination of the first foreign material information and the second foreign material information is performed online at the spinning process or offline by taking the sample of the fiber material or a subset thereof from the spinning process and examining it outside the spinning process.
5. Method according to one of the preceding claims, wherein the change to the spinning process (1) includes a change to the raw fibers fed into the spinning process (1) or at least a part thereof and/or a change to settings on machines involved in the spinning process (1).
6. Method according to one of the preceding claims, wherein the mutual assignment of the first foreign material information and the second foreign material information includes one of the steps from the following set: determining a passage time (Δt) as that time interval during which a fiber passes from the first position (11) to the second position (14) in the spinning process (1); determining a property of the sample itself; and marking a carrier of the sample.
7. Method according to claim 6, wherein

   at the first position (11) in the spinning process (1), a stream of fiber flocks pneumatically conveyed in an air stream is monitored for foreign materials and, based on the monitoring, the first foreign material information is determined, and

   at the second position (14) in the spinning process (1), yarn which has been spun from the fiber flocks and is conveyed along its longitudinal direction is monitored for foreign materials, and based on the monitoring, the second foreign material information is determined,

   a passage time (Δt) is determined as that time interval during which a fiber passes from the first position (11) to the second position (14) in the spinning process (1), the first foreign material information is determined at a first time (t₁) and the second foreign material information is determined at a second time (t₂) which is after the first time (t₁) by the passage time (Δt), and

   the first foreign material information thus determined and the second foreign material information thus determined are assigned to each other.
8. Method according to claim 7, wherein

   the first foreign material information is a first foreign material fraction indicating a proportion of foreign materials in the fiber flocks, and

   the second foreign material information is a second foreign material fraction indicating a proportion of foreign materials in the yarn.
9. Method according to claim 7 or 8, wherein at the first position (11) in the spinning process (1), foreign materials are eliminated from the stream of fiber flocks according to a removal criterion (26), and the change to the spinning process (1) includes a change to the removal criterion (26).
10. Method according to claim 9, wherein the first foreign material information is a removal rate (E) that indicates a number of removals per unit mass of fiber flocks or per unit time, a correlation between the removal criterion and the removal rate (E) is determined in advance, and this correlation is taken into account in the change to the spinning process (1).
11. Method according to one of claims 7 to 10, wherein foreign materials detected in the yarn at the second position (14) in the spinning process (1) are cleared out of the yarn according to a clearing criterion (36), and the change to the spinning process (1) includes a change to the clearing criterion (36).
12. Method according to claim 11, wherein the second foreign material information is a clearing rate (C) that indicates a number of clearing operations per unit mass of yarn, per unit length of yarn, or per unit time, a correlation between the clearing criterion (36) and the clearing rate (C) is determined in advance, and this correlation is taken into account in the change to the spinning process (1).
13. Method according to claim 9 or 10, wherein costs (K_E) for a removal are determined in advance and a product of the costs (K_E) for a removal and the removal rate (E) is taken into account in the change to the spinning process (1).
14. Method according to claim 11 or 12, wherein costs (K_C) for a clearing operation are determined in advance and a product of the costs (K_C) for a clearing operation and the clearing rate (C) is taken into account in the change to the spinning process (1).
15. Method according to one of claims 7 to 14, wherein the passage time (Δt) is entered manually by an operator, calculated automatically based on defaults, and/or retrieved from a database based on specifications.
16. Method according to one of the preceding claims, wherein

    first classes (27) of foreign materials are predetermined in the fiber material at the first position (11), which first classes (27) differ from each other with respect to properties of the foreign materials, and the first foreign material information relates to one or more of these first classes (27), and/or

    second classes (AA1-F) of foreign materials in the fiber material are predetermined at the second position (14), which second classes (AA1-F) differ from each other with respect to properties of the foreign materials, and the second foreign material information relates to one or more of these second classes (AA1-F).
17. Method according to one of the preceding claims, wherein the first foreign material information and the second foreign material information are output simultaneously to an operator, and the simultaneous output of the first foreign material information and the second foreign material information occurs at least partially graphically.
18. Method according to claim17, wherein in addition to simultaneously outputting the first foreign material information and the second foreign material information, an evaluation of the first foreign material information and/or the second foreign material information is output to the operator, and the evaluation includes at least two categories each indicative of appropriate and critical foreign material information, respectively.
19. Method according to claim 171817, wherein in addition to simultaneously outputting the first foreign material information and the second foreign material information, a recommendation for the change to the spinning process (1) is output to the operator.
20. Method according to one of the preceding claims, wherein an alarm is issued to an operator based on the first foreign material information and the second foreign material information assigned thereto.
21. Method according to claim 20, wherein a time course (74) of the first foreign material information and a time course (75) of the second foreign material information assigned thereto are determined, and the alarm is output based on the time courses (74, 75).
22. Method according to one of claims 17 to21, wherein the operator makes the change to the spinning process (1) based on the simultaneously output first foreign material information and second foreign material information, based on the evaluation, and/or based on the recommendation.
23. Method according to one of the preceding claims, wherein the change is made to the spinning process (1) automatically.
24. Device (2) for carrying out the method according to one of the preceding claims in a spinning mill carrying out a spinning process (1) through which a fiber material fed in the form of raw fibers and discharged in the form of yarn passes, containing a first monitoring device (3) at a first position (11) in the spinning process (1), which first monitoring device (3) is adapted to determine a first foreign material information relating to the foreign materials, and

    a second monitoring device (4) at a second position (14) in the spinning process (1) located downstream with respect to the first position (11), which second monitoring device (4) is adapted to determine a second foreign material information relating to the foreign materials,

    wherein the first position (11) and the second position (14), respectively, correspond in each case to a process step from the following set: opening, coarse cleaning, blending, fine cleaning (11), carding (12), doubling, combing, drafting, spinning (13), rewinding (14),

    characterized by

    a central control device (5) connected to the first monitoring device (3) and the second monitoring device (4), which is adapted for the purpose of

    assigning the first foreign material information and the second foreign material information to each other such that they relate to the same sample of the fiber material, and

    making a change to the spinning process (1) automatically on the basis of the first foreign material information and the second foreign material information assigned thereto.
25. Device (2) according to claim 2424, wherein the central control device (5) is adapted for the purpose of outputting the first foreign material information and the second foreign material information simultaneously to an operator.
26. Device (2) according to claim 24 or 25, containing

    a fiber flock monitoring device (3) at the first position (11) in the spinning process (1), which fiber flock monitoring device (3) is adapted to monitor a stream of fiber flocks pneumatically conveyed in an air flow for foreign materials and to determine the first foreign material information on the basis of the monitoring, and

    a yarn monitoring device (4) at the second position (14) in the spinning process (1), which yarn monitoring device (4) is arranged to monitor yarn spun from the fiber flocks and conveyed along its longitudinal direction for foreign materials and to determine the second foreign material information on the basis of the monitoring, wherein the central control device (5) is adapted for the purpose of

    storing a passage time (Δt) as that time interval during which a fiber passes from the first position (11) to the second position (14) in the spinning process (1), storing the first foreign material information at a first time (t₁) and the second foreign material information at a second time (t₂) which is after the first time (t₁) by the passage time (Δt), and

    assigning the first foreign material information thus determined and the second foreign material information thus determined to each other.

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