DE102022130133A1 - Method for detecting foreign bodies in fiber material - Google Patents

Abstract

The invention relates to a method for detecting foreign bodies in fiber material (3) which is accommodated in a filling shaft (2) of a processing machine (1; 100), in particular a spinning preparation machine, wherein the processing machine (1; 100) has a housing (26) with a housing opening (27) through which the filling shaft (2) can be viewed from the outside, and an inspection device (30) which closes the housing opening (27) and which comprises a separating element (32) with a transparent observation area (39) and at least one camera (54) which looks through the observation area (39) into the filling shaft (2), and wherein the method comprises the following repeating steps: recording (72) images of the fiber material (3) passing by the observation area (39) by means of the at least one camera (54); Evaluating (73) the recorded images by at least one evaluation unit (57) which is connected to the at least one camera (54) and is configured to determine a foreign body content of the fiber material (3) and provides the foreign body content as an output value; comparing (85) the output value with a predetermined and/or previous initial value; carrying out an optimization run (92) in which a position or rotational speed of at least one cleaning element (15, 16) for separating waste material from the fiber material (3) is automatically changed if the output value deviates from the initial value, wherein by means of a waste sensor device (22) a current waste composition of the separated waste material comprising foreign bodies and good fibers in a waste strand (21) downstream of the at least one cleaning element (15, 16) is determined (80) by means of at least one optical sensor (23, 24).

Description

The present invention relates to a method for detecting foreign bodies in fiber material that is accommodated in a filling shaft of a processing machine, in particular a spinning preparation machine. The processing machine has an inspection device with a separating element with a transparent observation area and at least one camera that looks through the observation area into the filling shaft.

In a spinning mill, the fiber quality of a fiber bale purchased, which may be made of cotton, polyester, mixed fibers or the like, is known. However, it is difficult to draw conclusions about the yarn quality from the quality of the fiber feed in the blow room. Quality fluctuations in the bale feed are often not recognized during the ongoing processing process and necessary adjustments to machine settings to always maintain optimal yarn quality despite quality fluctuations are not made. Of the many possible raw material parameters for fiber material, the recording of the foreign body content or disruptive particle content is a common parameter. Foreign bodies present in the pressed fiber bales include, for example, plant components such as stems, leaves, seeds (also generally referred to as "trash") or packaging residues such as fabrics, tissues, foils, plastic bands and the like. Of these foreign bodies, only the plant foreign bodies (trash) are recorded in the classified raw material parameters of the purchased bales. The other components can hardly be recorded by classic sampling with laboratory analysis devices due to their comparatively low frequency. In addition, the actual content is subject to very large fluctuations. But even with the content of plant components, there are such strong deviations between the actual raw material quality and the classified values that, with regard to the quality requirements of the end product, but also with regard to the use of energy and resource-saving handling of the raw material, a change in the settings of the processing machines would be necessary. In practice, however, readjusting the machines due to fluctuations in the raw material quality is not feasible because the available measurement methods via laboratory analysis are too slow to generate a corresponding control variable in time, i.e. while the material is still being processed, or it would involve considerable effort.

From the EP 3 951 032 A1 A device with a camera is known for detecting interfering particles in fiber material that is collected in a filling chute of a spinning preparation machine. The camera is arranged at an angle of maximum +/- 30 degrees to a vertical aligned with the fiber surface.

The object of the present invention is to further develop a method in such a way that the fiber material to be processed can be optically inspected with less effort and that an adjustment of the cleaning can be made if the foreign body content changes during the ongoing processing process.

The object is achieved by a method of the aforementioned type in that the processing machine has a housing with a housing opening through which the filling shaft can be viewed from the outside and which is closed by the inspection device or into which the inspection device is inserted, and in that the method comprises the following repetitive steps: taking pictures of the fiber material passing the observation area by means of the at least one camera; evaluating the recorded images by at least one evaluation unit connected to the camera, which is configured to determine a foreign body content and provides the foreign body content as an output value; comparing the output value with a predetermined and/or previous output value; carrying out an optimization run in which a position or rotational speed of at least one cleaning element for separating waste material from the fiber material is automatically changed if the output value deviates from the predetermined and/or previous output value, wherein a waste composition of the separated waste material comprising foreign bodies and good fibers is determined by means of a waste sensor device by means of at least one optical sensor.

For the sake of better readability, the component “the at least one camera”, “the at least one evaluation unit”, “the at least one cleaning element” or “the at least one sensor” will be referred to below only as “the camera”, “the evaluation unit”, “the cleaning element” or “the sensor”, whereby this will continue to refer to exactly one of the respective components or a plurality of the respective components. If the exact number is important, this will be indicated at the appropriate point.

The advantage is that by repeatedly recording and analyzing the images of the fiber material passing by the observation area, quality fluctuations or fluctuations in the foreign body content in the bale template or the fiber material taken up in the filling chamber detected early and adjustments to machine settings can be made automatically. Manual interventions, such as taking fiber samples for laboratory tests, are not provided for, which means that the fiber material in the processing machine can be visually inspected with little effort and the processing of the fiber material can be optimized during the ongoing processing process. The camera looks from the outside through the transparent observation area into the filling shaft and can visually inspect the fiber material passing by the observation area or its material surface. The fiber material thus remains in the filling shaft and the processing process of the fiber material is not disrupted by the inspection device attached from the outside. If the evaluation of the image data shows that the output value deviates from the initial value because the raw material quality or the foreign body content has changed, the position or rotation speed of the cleaning element can be readjusted. This takes place in the optimization run, in which the waste sensor device determines the waste composition in the separated waste material. The inspection device is used to determine the foreign body content of the fiber material in the filling shaft, and the waste sensor device is used to determine the waste composition in the waste stream downstream of the cleaning element.

The initial value can correspond to a foreign body content for which the cleaning element is set in order to obtain the best possible cleaning efficiency. If the output value, which reflects the current foreign body content, deviates from the initial value during the ongoing processing process, a readjustment may be necessary in order to continue to maintain the best possible cleaning efficiency despite the changed raw material quality. The optimization run thus serves to automatically adjust the cleaning efficiency when the foreign body content changes. Furthermore, the initial value after the optimization run has been carried out can be set equal to the value of the output value on the basis of which the optimization run was carried out. The evaluation unit then determines a new, i.e. current, output value, which in turn is compared with the initial value. If the new output value then deviates from the initial value, which can correspond to the value of the previous output value, the next optimization run is started, and so on. The initial value can also be a value specified in particular by the operator or machine operator. For example, when changing batches, it may be necessary to use a predetermined starting value in order to initially adjust the cleaning element to the bale quality purchased. The foreign body content can be in the usual range of 2 to 6 percent (mass ratio to raw cotton) when raw cotton is used as the starting product. If waste is added, the foreign body content can also be higher.

Depending on the operator's requirements for cleaning efficiency, a defined deviation of the output value from the initial value may be tolerable. This has the advantage that no optimization run is carried out if there are minor fluctuations in quality. For example, a percentage deviation of the output value of plus and/or minus 10 percent from the initial value may be acceptable, although larger or smaller deviations are also possible. The initial value can also be a range of values, with the optimization run only being carried out if the output value is outside the range of values.

Furthermore, the method can comprise at least one of the following steps, which can be carried out, for example, before carrying out the optimization run: determining the current waste composition by the at least one waste sensor device if the output value deviates from the predetermined and/or previous output value; comparing the current waste composition with a predetermined and/or previous waste value. By combining the results of the inspection device and the results of the waste sensor device, it is possible to distinguish whether the foreign body content has increased or whether the cleaning efficiency has deteriorated.

Furthermore, the process can include the optimization run step if the output value deviates from the specified and/or previous output value and if the current waste composition deviates from the specified and/or previous waste value. Depending on the operator's requirements for the degree of separation of good fibers, a percentage deviation of the current waste composition of, for example, plus and/or minus 10 percent from the specified and/or previous waste value can be specified, although larger or smaller deviations are also possible. The waste value can also be a range of values, with the optimization run only being carried out if the initial value and/or the output value are outside the respective range of values.

The cleaning element can be arranged on the preparation machine itself or on a spinning preparation machine upstream or downstream of the preparation machine. If several of the cleaning elements are provided, then these can be arranged on one of the machines or on several of the machines. Accordingly, the waste sensor device can be assigned to the machine that comprises the at least one cleaning element. The inspection device and the waste sensor device can be connected to one another, for example via a common machine control if both devices are assigned to the same machine, or via a higher-level control unit if the two devices are assigned to different machines. The upstream or downstream spinning preparation machine can also be a processing machine according to the invention or it can be a spinning preparation machine that does not have its own filling shaft or is not equipped with the inspection device.

In a further development, several of the machines can be combined to form a system that covers a processing line or at least part of the processing line in the spinning mill. Preferably, several of the machines within the system are each equipped with at least one of the inspection devices, provided they have a filling shaft that can be viewed from the outside. In this way, the quality characteristics of the fiber material, in particular the foreign body content, can be analyzed at several process points within the system. As a result, machines in the system can be automatically adapted to changes in the raw material quality depending on the raw material quality recorded.

The fiber material usually moves in the filling shaft at a slow transport speed, whereas the camera is held stationary. The fiber material preferably runs through the filling shaft from top to bottom, following the direction of gravity. The fiber material can sometimes be briefly accumulated in the filling shaft when the processing machine is in operation. In particular, a dosing device is arranged on the underside of the filling shaft and is configured to remove the fiber material from the filling shaft in doses. The dosing device can be, for example, a roller feeder and/or an opening roller. The material transport speed in the filling shaft, i.e. the transport speed, depends on a number of factors, for example the production rate, the material dissolution, the conveying pressure, etc., whereby the transport speed can be a few millimeters per minute to a few centimeters per minute. The transport speed is usually in a range of 20 to 800 millimeters per minute.

Due to the low transport speed, a large number of images can be recorded and evaluated to increase the accuracy of determining the foreign body content in the fiber material and the individual evaluation results can be accumulated to at least one output value. In order to generate an output value or measured value from the image data that reliably or statistically represents the foreign body content in the fiber material, it has proven advantageous if a minimum area of the fiber material is recorded and evaluated by the camera device. Very high accuracy was achieved if the minimum area was more than 2 square meters and more preferably at least about 3 square meters. More than 3.5 square meters did not show any significant improvement in terms of accuracy, but led to longer evaluation times. The minimum area can be a manually changeable value that the operator of the processing machine can adapt to his own quality specifications. In order to record the minimum area within the shortest possible time, the image recording frequency of the camera device can be increased. However, this is only possible to a limited extent due to the low transport speed of the fiber material, since if the image recording frequency is too high, the foreign bodies visible through the observation area can be counted multiple times. The time until the minimum area is recorded can also be reduced by using several of the inspection devices that take images of the fiber material at several points on the processing machine. If the processing machine has several of the filling shafts, such as a mixer with several filling shafts or chambers, the inspection devices can be arranged at each filling shaft and their images can each contribute to a part of the minimum area. If several of the inspection devices are arranged at the same filling shaft, it is advantageous if the inspection devices are distributed circumferentially around the transport direction and thus not arranged one above the other in order to avoid the same foreign body being recorded multiple times.

The waste sensor device is known, for example, from the patent specification DE 103 49 407 B4 known. The at least one optical sensor can be arranged in the waste strand of the processing machine and/or the upstream or downstream spinning preparation machine. The at least one optical sensor can determine the frequency of material separation, and thus also the waste composition, and can distinguish between desired waste (foreign bodies) and undesired waste (good fibers). The cleaning element can, for example, be an opening roller in a pre-cleaner, the rotation speed of which can be changed. Furthermore, the cleaning element can change the opening width of a separation grid by changing its position. Other options include adjustable separation knives that are attached tangentially to an opening roller, adjustable wings, suction hoods, etc. The processing machine can also be equipped with a variety of other adjustable cleaning elements.

Just as an example, let us assume that the quality of the raw material deteriorates during operation of the processing machine and that the cleaning efficiency of the processing machine decreases. Without the inspection device, the decrease in the quality of the raw material would go unnoticed. Another scenario would be that the amount of foreign bodies removed at the cleaning points decreases, which could be determined by measuring the composition of the waste. However, this does not mean that it can be determined whether the raw material has become cleaner or whether one of the processing machines, in particular the cleaner, needs to be re-optimized. The optimal setting therefore depends on the material and the level of contamination and can be adjusted if the properties of the raw material change during operation.

The waste sensor device can be configured to move the at least one cleaning element to a first end position during the optimization run, in which no foreign particles are separated, and then step by step to a second end position in which foreign particles and fibers are separated. The sensor signals of the waste sensor device are recorded and evaluated. The optimization run can be terminated at the point where a disproportionate amount of fiber material is separated compared to the proportion of foreign particles. For example, in a cleaner such as the universal cleaner CL-U from Trützschler, a first cleaning element in the form of a knife can be moved tangentially so that a cleaning point can be opened or completely or partially closed. A second cleaning element, which can be a pivoting wing, can be rotated about its pivot point so that a cleaning point can also be opened or completely or partially closed. In this way, little or no cleaning effect is achieved in the first end position, and in the second end position the cleaning effect can be better, but too many good fibers can end up in the waste along with the foreign particles. Instead of the complete optimization run, in which the first end position is approached first, it is also possible to check, starting from the current operating position of the cleaning element, by slightly adjusting the cleaning element, whether an improvement in the separation rate can be achieved by making small adjustments.

Furthermore, a cover element can be arranged on the separating element, wherein an interior space is formed between the separating element and the cover element, in which the at least one camera is arranged. The separating element and the cover element thus enclose the hollow interior space in which the camera can be protectively accommodated.

According to a first embodiment, the camera can be arranged and aligned such that an optical axis of the camera is aligned at least substantially parallel to the observation plane, and that a deflection device that deflects a beam path emanating from the observation area towards the camera is arranged in the interior formed between the separating element and the cover element. The camera thus looks indirectly at the observation area. This gives the inspection device a particularly flat design. In addition, the deflection of the beam path lengthens the distance between the camera and the observation area, which means that the detection area can be increased. The term "at least substantially parallel" is to be understood here to mean that the optical axis can be aligned parallel to the observation plane, whereby a preset deviation from parallelism in the range of plus 15 degrees to minus 15 degrees can be possible. In the event of a deviation from parallelism, an intersection point of the optical axis with the observation plane can lie outside the observation area, so that the camera cannot look directly at the observation area. The camera is preferably arranged and aligned such that the optical axis runs parallel to the observation plane.

The deflection device can have a reflective surface. An angle of incidence or reflection between the beam path and a surface normal of the reflective surface can be 45 degrees in each case. This arrangement is particularly suitable when the optical axis of the camera is aligned parallel to the observation plane. Alternatively, the angle of incidence or reflection can be greater than 45 degrees in each case and more preferably greater than 50 degrees and in particular less than 85 degrees. This allows the camera to be arranged closer to the separating element in order to provide a particularly flat inspection device. Depending on the orientation, the angle of incidence or reflection can also be less than 45 degrees and in particular greater than 15 degrees. This results in a somewhat greater installation depth of the inspection device, but this also requires a greater distance between the camera and the observation area, whereby the detection range of the camera can be increased. The deflection device can comprise at least one deflection element, in particular a mirror, whereby an optical waveguide or the like can be provided as an alternative to the mirror or as a further deflection element.

According to a second embodiment, which is an alternative to the aforementioned first embodiment, the camera or an optical axis of the camera can be aligned with the observation area. The camera thus looks directly at the observation area, so that in this embodiment no device for deflecting the beam path, such as the deflection device, is provided. The optical axis of the camera can intersect the observation area or an observation plane spanned by the observation area, preferably at an angle to an axis running perpendicular to the observation plane in a range of plus 60 degrees to minus 60 degrees.

For all designs, it is equally true that a dynamic pressure can be measured in the filling shaft, whereby the measured dynamic pressure can be used to correct the output value provided by the evaluation unit to a parameter that is independent of the dynamic pressure. This is because the number of foreign bodies visible in the observation area or in the image recorded by the camera depends considerably on the material resolution of the fiber material. A loose, well-resolved layer of material will present a small number of foreign bodies in the filling shaft to the camera. If, on the other hand, the material in the filling shaft is compressed by the application of transport air at a higher pressure, considerably more foreign bodies will be visible in the observation area or the image, and thus in the same area. A fluctuating dynamic pressure can therefore falsify the detection of the foreign body content. A pressure sensor for measuring the dynamic pressure can be arranged in the at least one filling shaft. A calibration curve can be stored in the evaluation unit. The pressure sensor can be arranged above a predetermined maximum fill level of the at least one filling shaft. The at least one inspection device can be arranged below the maximum filling level. To specify the maximum filling level, a light barrier or a light sensor can be arranged in the at least one filling shaft. The maximum filling level can be determined by an installation height of the light barrier or the light sensor.

Furthermore, the method can include the step of retrofitting the inspection device by inserting the inspection device into an existing housing opening of the processing machine through which the filling shaft can be viewed from the outside. Such a housing opening is usually equipped with a rigid or pivoting viewing window, a shaft door, a maintenance door, a maintenance flap or the like and can be provided with the inspection device instead. This means that a conventional processing machine, at least one housing opening of which is equipped with the viewing or access opening of a conventional type, i.e. without a built-in camera, can be retrofitted with the inspection device in order to be able to visually inspect the fiber material in the filling shaft. The inspection device can thus be referred to as an intelligent maintenance door or intelligent maintenance window. It goes without saying that the inspection device can also be installed ex works or when the processing machine is first delivered. In principle, however, it is also possible to create an opening in the housing of the processing machine specifically for the inspection device.

Depending on the application, the inspection device can be designed as a fixed or openable, in particular pivotable window. If the inspection device is designed to be openable, the filling shaft is accessible from the outside when the inspection device is open, for example in order to be able to remove a portion of the absorbed fiber material. When the inspection device is closed, the inspection device closes the housing opening, in particular hermetically. The latter also applies if the inspection device is designed to be fixed. The conventional maintenance windows that can be replaced by the inspection device usually have an external width of at least approximately 400 millimeters and an external height of at least approximately 800 millimeters. The external dimensions of the inspection device are preferably selected such that the inspection device can be inserted into the existing housing opening instead of the maintenance windows. In particular, the inspection device, in particular the opening closure device, can have an external width of between 200 millimeters and 600 millimeters and an external height of between 400 millimeters and 1200 millimeters. Preferably, the external width is in a range of 300 millimeters and 500 millimeters and the external height is in a range of 600 millimeters and 1000 millimeters.

The separating element and the cover element form an opening closure which can accommodate further components such as a frame for insertion into the housing openings, pivoting means, locking means, seals and the like. The inspection device can preferably be handled as a structural unit. To operate the inspection device, it can be connected to an electrical supply, in particular to the processing machine. Means for data transmission can also be provided. For example, the camera can have an interface for connecting to the evaluation unit and/or the control unit. The inspection device can comprise the evaluation unit, which can be accommodated in particular in the interior of the opening closure device. The control unit can be a control unit of the processing machine or a higher-level system control or.

The camera and the optional deflection device are preferably housed entirely in the interior of the opening closure device. The separating element is designed to be transparent, at least in the observation area, so that the camera can take pictures of the fiber material or its fiber material surface through the observation area. For example, the separating element can be a glass or plastic pane. It is advantageous that the fiber material passing by the separating element keeps the separating element clean and dust-free. The interior and/or the inspection device as a whole are intended to be arranged outside the filling shaft. The separating element separates the interior from the filling shaft of the processing machine so that the camera has no contact with the fiber material and is protected accordingly. In other words, the separating element is arranged on a side of the inspection device facing the filling shaft, whereas the cover element is arranged on a side of the inspection device facing away from the filling shaft. The cover element is arranged on the separating element and thus covers the camera arranged between the separating element and the cover element in a protective manner from the outside. The cover element and the separating element are preferably firmly connected to one another. The separating element can be designed to be flat, whereby its design can preferably correspond to the shape and contour of the housing wall of the filling shaft surrounding the housing opening in order to ensure that the fiber material can pass by without interference. The separating element can be arranged flush with the housing wall surrounding the housing opening. The separating element can also be referred to as a separating wall. The cover element can be designed to form the interior space, for example, in the form of a tub or bowl. The cover element and the separating element

A lighting device for illuminating the fiber material guided past the observation area can be arranged in the interior of the opening closure device. This allows the fiber material moving past the observation area in the filling shaft of the processing machine to be illuminated with incident light. The lighting device can extend over the entire width of the observation area. In particular, the lighting device can comprise a plurality of light-emitting diodes or LED light sources, which can have lenses in order to evenly distribute the light emitted by the respective light-emitting diode. This ensures uniform illumination of the observation area. Furthermore, the lighting device can have a lower lighting element and an upper lighting element, with the observation area being arranged between the two lighting elements. For example, the upper and/or lower lighting element can each be designed in the form of a light bar or LED bar. To avoid light reflections on the images taken with the camera, the at least one lighting element directed towards the observation area can be arranged at an angle of incidence that deviates significantly from the surface normal of the observation plane. This is particularly useful when the upper and lower lighting elements are arranged above and below the observation area. It is also possible for the angle of incidence of the lighting element to be directed perpendicularly to the observation plane. This is particularly advantageous when the beam path between the observation area and the optional deflection device runs at an angle to the surface normal.

The observation area can be illuminated by the lighting device at least when an image is taken. In a further development, the observation area can be permanently illuminated by the lighting device. This can be advantageous, among other things, if the camera is a line camera. Likewise, flash operation, in which the lighting device generates flash lights, can also be advantageous if illumination is to be provided alternately with light of different wavelengths or if the movement of the fiber material along the observation area is so slow that the light can be switched off between the individual image recordings.

The number of cameras used depends, among other things, on the width of the observation area, the maximum detection width of the respective camera, the size of the interior, the distance of the camera from the observation area and the like. Preferably, exactly one or two of the cameras are provided. To enlarge To reduce the detection width of the respective camera, it can be placed as high up in the interior as possible. The focal length of the lens can also be reduced. However, this can lead to a large viewing angle towards the edge of the detection area, which can have optical disadvantages. If several cameras are used, they can be arranged next to each other and, in particular, at a distance from each other in the direction of the width of the separating element. The detection areas of neighboring cameras can also overlap to ensure complete coverage of the observation area.

The camera can form a camera device together with the evaluation unit, also called an image evaluation computer. The camera device can accordingly comprise one or more of the cameras. The evaluation unit can analyze the image data from the assigned camera(s). This ensures particularly efficient processing of the image data, especially when a processing machine has several of the inspection devices. The evaluation unit is preferably arranged in the interior between the cover element and the separating element. In principle, however, it is also possible for the evaluation unit to be arranged outside the interior and, for example, to be housed on or in the processing machine.

The camera can be a line camera. This enables a large detection width or detection over a large viewing angle along the line, which can be aligned in the direction of the width of the observation area or the width of the housing opening. The line camera records the image line by line. The individual image lines can be combined by the evaluation unit to form a continuous image. The fiber material moves past the observation area and the camera device is held stationary on the opening closure device, i.e. the camera stands still. The detection area, or the image field at the moment of recording, is a slot the width of the desired image, which preferably corresponds at most to the width of the separating element. As a result, the line camera only needs a very small installation depth, so that the deflection device, if present, can be arranged close to the separating element and the opening closure device can be designed to be flat overall. In addition, the observation area can be narrow in height and correspondingly wide in width. In order to avoid optical disadvantages caused by large viewing angles at the edges, it is advantageous if the viewing angle from the center of the camera to the edges of the image is a maximum of 15°. In a typical opening closure device for a cleaner, a mixer and the like, the beam path or a total optical path length of at least approximately 550 millimeters can be achieved. This makes it possible to cover an observation area of at least approximately 300 millimeters wide and 0.3 millimeters high.

In order to ensure that each line of the fiber material is optimally scanned only once, a time interval of at least 10 seconds and a maximum of 600 seconds can be provided between the individual images due to the fiber material usually being slowly moved past, although longer and shorter time intervals are also possible in principle.

In principle, the at least one camera can also be an area or matrix camera, and combinations are also possible in which the camera device comprises at least one line and at least one area or matrix camera. The respective camera can have at least one image sensor and one lens in a manner known per se. The optional deflection device can have a deflection element for each camera, whereby in principle a continuous deflection element can also be provided, to which the cameras can be aligned.

When designed with the deflection device, the opening closure device can have an upper section and a lower section spaced apart from the upper section along the optical axis. The camera can be arranged in the upper section and the observation area and the deflection device can be arranged in the lower section, or vice versa. In order to be able to increase the distance between the camera and the deflection device and the observation area as a whole, further components that are not part of the camera's optics, such as the evaluation unit for determining the raw material quality, in particular for detecting foreign bodies, in particular with brightness and/or color deviations, a control unit and the like, can be arranged one behind the other in the depth of the interior. In particular, the evaluation unit and/or the control unit can be arranged between the camera and the cover element. When designed without the deflection device, the opening closure device can have a section in which the camera and the observation area are arranged. To seal off the observation area from ambient light or external light, the cover element can be designed to be opaque in the (in particular lower or upper) section in which the observation area is located. This Disturbing light reflections in the observation area are avoided.

The opening closure device can be a carrier for further auxiliary sensors. In particular, an idle monitoring device for the filling shaft can be arranged on the outside of the separating element and/or in the interior of the opening closure device. This can comprise, for example, a light barrier or a light switch.

Furthermore, the opening closure device can have a viewing section that is above and/or below the observation area. In other words, the observation area, in which the cover element can be designed to be opaque, is outside the viewing section. In the viewing section, the separating element and the cover element can be transparent. In particular, the viewing section is arranged between the upper section and the lower section. Preferably, the viewing section directly borders the upper section at the top and the lower section at the bottom. In this way, the inspection device not only offers the possibility of optically inspecting the fiber material using the camera device, but can also be used as an observation opening through which a human operator can look into the filling shaft of the processing machine from the outside in order to be able to inspect the fiber material passing the separating element of the opening closure device. In principle, the viewing section can also be the upper section, in which the camera device can be arranged, or it can extend over the middle section and the upper section. Furthermore, the entire cover element can be designed to be transparent and can be made, for example, from a transparent glass or plastic material. At the level of the observation area, in particular in the lower section of the opening closure device, the cover element made from the transparent material can be covered with foil, painted or the like in order to seal off the observation area from disturbing external light.

Furthermore, the processing machine can have several of the housing openings, with one of the inspection devices being inserted in at least a subset of the housing openings. Furthermore, two of the inspection devices can be provided for each filling shaft, which can be arranged facing each other on a front and a rear side of the processing machine.

The preparation machine can be a spinning preparation machine, in particular a bale opener, for example Trützschler Universal Bale Opener BO-U, a cleaner, for example Trützschler Universal Cleaner CL-U, an opener, for example Trützschler Universal Opener TO-U, a mixer, for example Trützschler Universal Mixer MX-U, a flock mixer, for example Trützschler T-Blend, a card, for example Trützschler TC21, and the like. Furthermore, the preparation machine can be from the field of nonwovens production, such as an opener, for example Trützschler Fine Opener TBL-FB or TBL-FO, a mixing chamber, for example Trützschler TBL-BB, a carding machine, for example Trützschler TWF-NC, and the like.

• 1 eine schematisch vereinfacht dargestellte Aufbereitungsmaschine gemäß einer ersten Ausführungsform der Erfindung, wobei die Aufbereitungsmaschine eine erfindungsgemäße Inspektionseinrichtung mit einer Kamera, einer Ablenkungsvorrichtung und zwei Beleuchtungselementen umfasst;
• 2 eine teilgeschnittene Seitenansicht der Aufbereitungsmaschine;
• 3 eine vergrößerte Teildarstellung der Aufbereitungsmaschine in schematisch vereinfachter Schnittansicht;
• 4 eine vergrößerte Teildarstellung der Aufbereitungsmaschine im Bereich der Inspektionseinrichtung, wobei die Kamera mit einer ersten Brennweite eingestellt ist;
• 5 die vergrößerte Teildarstellung aus 4, wobei die mit einer zweiten Brennweite eingestellt ist;
• 6 eine schematische Darstellung eines Ablaufdiagramms der Aufbereitungsmaschine in einem Automatikbetrieb;
• 7 eine schematische Darstellung eines Teilschritts des Ablaufdiagramms aus 6, der die Ermittlung eines Fremdkörpergehalts im Fasermaterial betrifft;
• 8 eine schematische Darstellung eines weiteren Teilschritts des Ablaufdiagramms aus 6, der die Durchführung eines Optimierungslaufs betrifft;
• 9 eine vergrößerte Teildarstellung einer Aufbereitungsmaschine gemäß einer alternativen Ausführungsform in schematisch vereinfachter Schnittansicht, wobei die Aufbereitungsmaschine mehrere der Inspektionseinrichtungen umfasst;
• 10 eine vergrößerte Teildarstellung der Aufbereitungsmaschine im Bereich einer Inspektionseinrichtung gemäß einer alternativen Ausführungsform mit zwei Kameras;
• 11 eine vergrößerte Teildarstellung der Aufbereitungsmaschine gemäß einer noch weiteren Ausführungsform in schematisch vereinfachter Schnittansicht;
• 12 eine Seitenansicht einer Aufbereitungsmaschine gemäß einer weiteren Ausführungsform der Erfindung; und
• 13 eine vergrößerte Teildarstellung der Aufbereitungsmaschine gemäß einer alternativen Ausführungsform, wobei die Aufbereitungsmaschine eine erfindungsgemäße Inspektionseinrichtung gemäß einer weiteren Ausführungsform mit einer Kamera und zwei Beleuchtungselementen umfasst, wobei die Kamera direkt auf einen Beobachtungsbereich blickt.

Further features and advantages of the invention will become apparent from the following description of preferred embodiments. Features that are essentially or functionally the same or similar are provided with the same reference numerals. They show:

• 1 a schematically simplified representation of a processing machine according to a first embodiment of the invention, wherein the processing machine comprises an inspection device according to the invention with a camera, a deflection device and two lighting elements;
• 2 a partially sectioned side view of the processing machine;
• 3 an enlarged partial representation of the processing machine in a schematically simplified sectional view;
• 4 an enlarged partial view of the processing machine in the area of the inspection device, with the camera set to a first focal length;
• 5 the enlarged partial view from 4 , which is set to a second focal length;
• 6 a schematic representation of a flow chart of the processing machine in an automatic mode;
• 7 a schematic representation of a sub-step of the flow chart from 6 , which concerns the determination of the foreign body content in the fibre material;
• 8th a schematic representation of another sub-step of the flow chart from 6 , which concerns the execution of an optimization run;
• 9 an enlarged partial view of a processing machine according to an alternative embodiment in a schematically simplified sectional view, wherein the processing machine comprises several of the inspection devices;
• 10 an enlarged partial view of the processing machine in the area of an inspection device according to an alternative embodiment with two cameras;
• 11 an enlarged partial view of the processing machine according to yet another embodiment in a schematically simplified sectional view;
• 12 a side view of a processing machine according to another embodiment of the invention; and
• 13 an enlarged partial view of the processing machine according to an alternative embodiment, wherein the processing machine comprises an inspection device according to the invention according to a further embodiment with a camera and two lighting elements, wherein the camera looks directly onto an observation area.

In the 1 and 2 a processing machine 1 according to a first embodiment of the present invention is shown, which is designed as a cleaning machine, i.e. cleaner. Further details and possible modifications are shown in the 3 to 5 shown. In the figures, a longitudinal direction X, a transverse direction Y and a vertical direction Z are shown to illustrate the orientation of the processing machine 1 in space, which are defined in terms of a Cartesian coordinate system assigned to the processing machine 1 and are indicated by corresponding arrows. Terms such as "below", "below", "above" or "above" represent spatial information in relation to the vertical direction Z. The processing machine 1 can be set up on a stationary floor that lies in a horizontal plane spanned by the longitudinal direction X and the transverse direction Y.

In the 1 it can be seen that the processing machine 1 has a filling shaft 2. The filling shaft 2 is connected to an inlet 4, through which fiber material 3, usually provided in flake form, is fed from an upstream processing machine, for example a 12 shown mixer, here the Trützschler Universal Mixer MX-U, can be introduced pneumatically. In an upper part 5 of the filling shaft 2, a dedusting device 6, which separates dust and transport air from the fiber material 3, is arranged. The transport air is discharged via an exhaust air line 7 and the fiber material 3 falls into a lower part 8 of the filling shaft 2, in which it is accumulated during operation of the processing machine 1. For this purpose, a dosing device, here in the form of a roller feeder 9, is arranged in the lower part 8, which, here as an example, has two slowly rotating feed rollers 10, 11 that are directed in opposite directions of rotation and below the feed rollers 10, 11 two slowly rotating feed rollers 12, 13 that are directed in opposite directions of rotation. The feed rollers 12, 13 form the bottom of the filling shaft 2, under which an opening roller 14 is arranged.

A first cleaning element 15 and a second cleaning element are assigned to the opening roller 14 in its direction of rotation. Such an arrangement is described in the published patent application EN 10 2012 012 254 A1 by the applicant, which is fully incorporated or referred to hereby. The first cleaning element 15 can be moved at least substantially tangentially with respect to a tip circle 17 of a set 18 of the opening roller 14 along the double arrow A in order to adjust the passage of the cleaning point. The waste material separated by the cleaning elements 15, 16 passes through suction hoods 19, 20 into a waste strand 21. In the direction of rotation of the opening roller 14 behind the second cleaning element 16, a pipe system is connected, via which the cleaned fiber material 3 can be transported to a subsequent processing machine (not shown), for example a foreign part separator, such as the Trützschler SP-FPU, T-Scan TS-T3 or T-Scan TS-T5. A transport direction of the cleaned fiber material 3 to the subsequent processing machine is shown in the 1 indicated by the arrow T.

In the 2 it can be seen that the waste material sucked into the waste line 21 via the suction hoods 19, 20 is guided past a waste sensor device 22. The waste sensor device 22 has an optical measuring device with a sensor 23, 24 for each suction hood 19, 20, in particular a brightness sensor, which looks into the respective suction hood 19, 20 via a transparent partition wall. The sensors 23, 24 can be used to detect the waste material transported away via the suction hoods 19, 20 through a waste channel 25 of the waste line 21 in order to detect good fibers in the waste stream within the fibers flying past. By evaluating the measurement results, the proportion of good fibers in the waste material or the waste composition of the waste material comprising foreign bodies and good fibers can be determined.

Above the roller feed 9, a housing opening 27 is formed in a housing 26 of the processing machine 1 that encloses the filling shaft 2. Above the housing opening 27, a light barrier 28 connected to a machine control system (not shown) or a light sensor is arranged, which serves as a fill level limiter. As soon as a fill level F of the fiber material 3 in the filling shaft 2 rises to the installation height of the light barrier 28, the feed of fiber material 3 to the processing machine 1 is interrupted until the fill level F has dropped again. In this way, the installation height specifies the maximum fill level F _max . Furthermore, a pressure sensor 29 is arranged above the light barrier 28 in the filling shaft 2, which can be designed as a differential pressure sensor in order to measure the difference between the room pressure prevailing in the filling shaft 2 and the ambient pressure prevailing outside the filling shaft 2. This makes it possible to determine the influence of the dynamic pressure due to the transport air flowing into the filling shaft 2, which presses on the fiber material 3 from above and compresses it. Instead of a differential pressure sensor, two separate pressure sensors can also be used.

An inspection device 30 according to the invention is inserted into the housing opening 27 of the housing 26 of the processing machine 1, the structure and functioning of which is explained in detail below. In the 1 and 2 it can be seen that the inspection device 30, here by way of example, is designed as a pivotable access or inspection door, which is hinged to the housing 26 by means of hinge means 61. Furthermore, mechanical locking means 62 can be provided in order to be able to lock the inspection device 30 in its closed state. In principle, the inspection device 30 can also be a fixed window that has no hinge means 61 and no locking means 62.

In the 3 it can be seen that the inspection device 30 has an opening closure device 31 which comprises a separating element 32 and a cover element 33. The separating element 32 is designed like a plate and can be flush with a housing wall 34 of the filling shaft 2 surrounding the housing opening 27. When the processing machine 1 is in operation, the fiber material 3 moves or brushes past the inside of the housing wall 34 and an outside 35 of the separating element 32 facing the filling shaft 2 in the direction of the arrow provided with the reference number 63. Furthermore, the opening closure device 31 can have a frame 36 which encloses the separating element 32 and the cover element 33 for fastening the opening closure device 31 to the housing 26. The opening closure device 31 can thus be used like a fixed window, although pivoting or folding means for designing the opening closure device 31 as a pivoting window or flap are also possible in principle. The frame 36 can also be made up of several parts and have a frame part fixed to the housing 26 and a frame part that can be separated from it and which comprises the unit made up of the separating element 32 and the cover element 33, in order to be able to remove this unit in a simple manner and thereby provide access to the filling shaft 2 for inspection or maintenance work. An interior space 37 is formed between the separating element 32 and the cover element 33. Seals (not shown) can be provided in a manner known per se to seal the housing opening 27 and the interior space 37 against dust and moisture.

A camera device 38 is arranged in the interior 37 of the opening closure device 31 in order to be able to take pictures of the fiber material 3 which passes in the filling shaft 2 at a defined observation area 39 of the separating element 32 in the direction of the arrow 63. For this purpose, the separating element 32 is transparent in the observation area 39, whereby, as shown here by way of example, the entire surface of the separating element 32 is transparent. The outer side 35 of the separating element 32 defines an observation plane E, to which an optical axis 40 of the camera device 38 is aligned parallel. Furthermore, a deflection device 41 is accommodated in the interior 37 of the opening closure device 31, which is arranged in the field of view of the camera device 38 and deflects a beam path 42 emanating from the observation area 39 towards the camera device 38. The deflection device 41 comprises, here as an example, a mirror with a reflective surface 47. The angle of incidence and reflection is 45 degrees, so that the beam path 42 is deflected by 90 degrees. In the 3 It can be seen that a first beam path section 43 of the beam path 42 runs perpendicular to the observation plane E and that the beam path 42, after deflection, has a second beam path section 44 aligned parallel to the optical axis 40.

The camera device 38 is arranged, here by way of example, in an upper section 45 of the opening closure device 31. The deflection device 41 arranged at a distance from the camera device 38 is, here correspondingly, accommodated in a lower section 46 of the opening closure device 31, in which the observation area 39 is also formed. In principle, a reverse arrangement is also possible, in which the camera device 38 can be arranged in the lower section 46 and the deflection device 41 and the observation area 39 can be arranged in the upper section 45. By adjusting the distance between the camera device 38 and the deflection device 41, a detection width 48 of the Camera device 38, i.e. a width of the scan line, can be specified, which expediently corresponds to a maximum clear width 49 of the frame 36. In the 4 and 5 the camera device 38 is arranged at two different distances from the deflection device 41. The camera device 38 is fixed in the respective position. A guide device (not shown), which can comprise, for example, a rail, rod, a plate with a hole pattern or the like, can be provided in the interior 37 in order to be able to align the camera device 38 and adjust the inspection width via the distance from the deflection device 41.

To illuminate the fiber material 3 moving past the observation area 39, a lighting device 50 is arranged in the interior 37 of the opening closure device 31. The lighting device 50 has an upper lighting element 51 and a lower lighting element 52, which illuminate the observation area 39 obliquely from above and below, respectively. The observation area 39 is thus arranged between the two lighting elements 51, 52. Along the optical axis 40, the deflection device 41 is arranged between the camera device 38 and the lower lighting element 52 and the upper lighting element 51 is arranged between the camera device 38 and the deflection device 41. The two lighting elements 51, 52 are designed like strips and extend at least over the detection width 48 of the camera device 38. The lighting elements 51, 52 can comprise a plurality of LED light sources 53 with lenses. To avoid light reflections, the angles of incidence deviate from the surface normal of the observation plane E and intersect the observation plane E, here as an example, in a range between 20 degrees and 80 degrees. To seal off the observation area 39 from ambient light or external light, the cover element 33 can be designed to be opaque in the lower section 46.

The camera device 38 has a camera 54, here for example a line camera, with a lens 55, although in principle an area camera can also be provided. The camera 54 is connected via a data line 56 to an electronic evaluation unit 57, which analyzes the image data received from the camera device 38. The evaluation unit 57 is configured to evaluate the number, frequency and/or total area of foreign bodies in the fiber material using image processing methods in order to be able to output a foreign body content in the fiber material 3. The evaluation unit 57 can recognize the foreign bodies, for example, based on brightness and/or color deviations. The evaluation unit 57 is arranged in the interior 37, here for example in the upper section 45. In this way, the fiber material can be optically inspected from the machine side equipped with the inspection device 30 in order to detect foreign bodies in the fiber material 3.

The embodiment of the processing machine 1 shown here has only a single inspection device 30. A housing wall 58 opposite the inspection device 30 is, here, closed, but can have inspection openings and the like in a manner known per se, into which an inspection device 30 could in principle also be inserted.

The inspection device 30 can have an interface in order to be able to connect the inspection device 30 to an electrical supply system and/or a bus system, in particular a field bus, after installation in the housing opening 27. The interface can, for example, comprise plug contacts, connection points or the like, which are connected to at least one counter element arranged on the machine side. In this way, the electronic components of the inspection device 30, such as the camera device 38, the lighting device 50 and the evaluation unit 57, can be supplied with voltage and/or coupled to a control unit in order, for example, to be able to transfer the output values of the evaluation unit 57 to the control unit. The control unit can be assigned to the processing machine or be a higher-level system control that communicates with a large number of control units of other processing machines.

When the processing machine 1 is in operation, the fiber material 2 is pneumatically transported via the inlet 3 into the filling shaft 2. The transport air is discharged via the dust removal device 6 and the fiber material 3 collects in the lower part 8 of the filling shaft 2. Due to the slow-working roller feed 9, it accumulates in the filling shaft 2, with the fill level F usually being above the observation area 39 and below the light barrier 28. At high production rates, it can happen for a short time that the fill level F is below the observation area 39. In order to avoid images being taken at this time, fill level sensors such as another light barrier, light sensors and the like can be provided.

In the 6 A possible flow chart for an automatic operation of the processing machine 1 is shown. With Start 65, the cleaning elements 15, 16 are already set to a predetermined initial value by means of an initial Opti optimization run. The specified initial value can correspond to a manually entered foreign body proportion which is determined by the operator on the basis of the purchased or examined raw material quality. The optimization run can be carried out while the processing machine 1 is in operation, in which the roller feed 9 and the opening roller 14 continue to rotate. During the optimization run, the optical sensors 23, 24 of the waste sensor device 22 check the waste material sucked out via the suction hoods 19, 20 for its waste composition. At the start of each optimization run, the first cleaning element 15 can first be moved to a first position in which the cleaning point or cleaning opening is closed. The degree of foreign bodies separated out will initially be low in the first position. The first cleaning element 15 can then be moved along the double arrow A and gradually release the cleaning opening, whereby the proportion of foreign bodies will increase. From a certain point onwards, the proportion of good fibers will continue to increase in relation to the proportion of foreign bodies. The first cleaning element 15 is then moved to the position in which the ratio between foreign bodies and good fibers was most favorable in this optimization run. The ratio between foreign bodies and good fibers resulting from the optimization run is saved as the waste value. Depending on the specifications stored in the control unit or specified by an operator of the processing machine 1, machine units that influence the waste composition, here the cleaning elements 15, 16, can thus be automatically adjusted until the desired waste quality is achieved. The optimization run carried out on the basis of the initial value thus optimizes the cleaning efficiency of the processing machine 1.

After starting 65 the automatic operation, the current or actual foreign body content in the fiber material 3 is recorded or monitored in step 70. The step 70 comprises various sub-steps which are shown in the flow chart in the 7 are reproduced. After starting 71 the foreign body detection, the camera device 38 takes a picture of the fiber material 3 passing behind the observation area 39 in sub-step 72, the lighting device 50 illuminating the observation area 39 during the recording using the incident light method. The evaluation unit 57 then evaluates the image data transmitted by the camera device 38 for the captured image in sub-step 73. The received image data are evaluated using image processing methods in relation to the number, frequency and/or total area of foreign bodies in the fiber material 3. As a rule, foreign parts such as stems, leaves or general "trash" particles appear as dark spots on the otherwise cream to white colored fiber material 3. Because almost binary states are present, the segmentation between the foreign bodies being sought against the light background of the fiber material 3 is possible, for example by means of threshold operations. A classic decomposition of the scene into objects with characteristics such as size, area, contour, etc. can follow. The foreign body content can be determined by counting the dark objects or by accumulating the area. Size histograms or a classification of the objects into groups such as trash, stems, leaves, etc. can also be used.

In sub-step 74, it is queried whether the image area captured by the camera device 38 corresponds to a defined minimum area. In order to generate an output value or measured value from the image data that reliably or statistically represents the foreign body content in the fiber material, it has proven advantageous if the minimum area captured by the camera device 38 has a defined minimum value. A very high level of accuracy is achieved if the minimum area is more than 2 square meters and more preferably at least approximately 3 square meters. Due to the small capture area of the line camera 54 compared to the minimum area of, for example, only 90 square millimeters, further images are captured 72 and evaluated 73 until the defined minimum area has been reached.

In order to be able to react as quickly as possible to the changing proportion of foreign bodies in the fiber material 3 by adjusting the cleaning elements 15, 16, one goal is to capture the defined minimum area of the fiber material 3 in the shortest possible time without capturing foreign bodies multiple times. Since the processing machine 1 shown here only has a single inspection device 30, the required minimum area must therefore be captured by the images of the one camera device 38. The capture area of the camera device 38 can be increased, for example, by increasing its distance from the deflection device 41 or the observation area 39, whereby a larger area can be captured with one image. The image recording frequency depends on the transport speed and can only be increased to a limited extent in order to avoid multiple counting of the same foreign bodies. The images can be captured at an example transport speed of 120 to 360 millimeters per minute with an image recording frequency of 13 to 80 hertz. If the capture or image area of an image of the camera device 38 is assumed to be 90 square millimetres, the measuring time until Reaching the minimum area of 3 square meters, for example, takes 14 minutes. Higher transport speeds, which can be achieved through higher production rates, enable a higher image recording frequency, which means that the minimum area can be recorded more quickly. When evaluating the image, the evaluation unit 57 takes into account images constructed line by line, as is usual for line cameras, and evaluates these with image processing algorithms for foreign bodies. The evaluation results of the individual images are accumulated in order to improve the accuracy of determining the proportion of foreign bodies in the fiber material 3.

In sub-step 75, the evaluation unit 57 takes into account the dynamic pressure in the filling shaft 2 measured by the pressure sensor 29 when evaluating the image. The transport air flowing into the filling shaft 2 always leads to a certain compression of the fiber material 3 in the filling shaft 2, which can influence the accuracy of the output value. In order to minimize this influence and, if possible, eliminate it, the pressure sensor 29 is coupled to the evaluation unit 57. With the help of the measured dynamic pressure and a calibration curve stored in the evaluation unit 57, the output value of the evaluation unit 57 can be corrected to a parameter that is independent of the dynamic pressure. The evaluation unit 57 outputs its corrected output value to a control unit of the processing machine 1. The corrected output value is transmitted to the control unit, see sub-step 76. The detection of the foreign body content ends with 77. The process for detecting foreign bodies according to sub-steps 71 to 77 can be repeated regularly. Several of the detection processes can also run simultaneously with a time offset, whereby a current foreign body content can be provided at shorter time intervals using the updated output value.

According to the 6 According to the flow chart shown, step 70 is followed by a step 80 in which the waste composition is determined by means of the waste sensor device 22. The waste sensor device 22 can regularly and in principle also permanently monitor the waste composition, so that step 80 can also run simultaneously with step 70. The waste sensor device 22 uses the optical sensors 23, 24 to determine the waste composition or the proportion of good fibers in the waste material extracted via the extraction hoods 19, 20.

Based on the corrected output values and the waste composition in particular, a decision can be made in step 85 as to whether optimization of the cleaning of the processing machine 1 is required ("yes"). If none of the criteria mentioned below is met, the cleaning elements 15, 16 are currently optimally adjusted and no optimization is necessary at this point in time ("no"), so that the method is continued with the loop comprising steps 70, 80 and 85.

• - wenn der insbesondere korrigierte Ausgabewert im Vergleich mit dem beim vorherigen bzw. initialen Optimierungslauf gesetzten bzw. vorgegebenen Ausgangswert gleichgeblieben ist oder zumindest innerhalb eines vorgebbaren Toleranzbereichs um den Ausgangswert liegt, jedoch die Abfallzusammensetzung bzw. Abfallmenge von dem beim vorherigen Optimierungslauf gesetzten Abfallwert abweicht und insbesondere außerhalb eines vorgebbaren Toleranzbereichs um den Abfallwert liegt;
• - wenn die Abfallzusammensetzung bzw. Abfallmenge im Vergleich mit dem beim vorherigen bzw. initialen Optimierungslauf gesetzten Abfallwert gleichgeblieben ist oder zumindest innerhalb eines vorgebbaren Toleranzbereichs um den Abfallwert liegt, jedoch der insbesondere korrigierte Ausgabewert sich über die Zeit betrachtet verändert hat, weil der Ausgabewert außerhalb des vorgebbaren Toleranzbereichs liegt, ein sprunghafter Anstieg des Ausgabewerts erfasst wurde oder bei Betrachtung des Integrals über die Zeit eine kontinuierliche Erhöhung oder Verringerung erkannt wird;
• - wenn sowohl der insbesondere korrigierte Ausgabewert im Vergleich mit dem Ausgangswert außerhalb des vorgebbaren Toleranzbereichs um den Ausgangswert liegt als auch die Abfallzusammensetzung bzw. Abfallmenge außerhalb des vorgebbaren Toleranzbereichs um den Abfallwert liegt.

The optimization is performed in step 90 if one of the following criteria is met:

• - if the output value, in particular corrected, has remained the same in comparison with the initial value set or specified in the previous or initial optimization run or is at least within a predeterminable tolerance range around the initial value, but the waste composition or waste quantity deviates from the waste value set in the previous optimization run and in particular is outside a predeterminable tolerance range around the waste value;
• - if the waste composition or waste quantity has remained the same compared to the waste value set in the previous or initial optimization run or is at least within a predeterminable tolerance range around the waste value, but the output value, in particular corrected, has changed over time because the output value is outside the predeterminable tolerance range, a sudden increase in the output value was recorded or a continuous increase or decrease is detected when considering the integral over time;
• - if both the particularly corrected output value in comparison with the initial value lies outside the predeterminable tolerance range around the initial value and the waste composition or waste quantity lies outside the predeterminable tolerance range around the waste value.

The optimization 90 comprises various sub-steps, which are shown in the flow chart in the 8th are reproduced. After start 91, the optimization run 92 is carried out, in which the position of the cleaning elements 15, 16 is changed in step 92 and the changing waste composition is monitored by means of the waste sensor device 22. In this case, depending on the specifications stored in the control unit or specified by the operator of the processing machine 1, the machine units that influence the waste composition, here the cleaning elements 15, 16, are automatically adjusted until the desired waste quality is achieved for the recorded output value, which reflects the current foreign body content. Instead of the complete optimization run 92, in which the first position is initially approached, it is also possible to start from the previously set operating point by slightly changing the setting. By setting the cleaning elements 15, 16, it can be checked whether an improvement in the separation efficiency can be achieved by making small adjustments. In sub-step 93, the current output value is recorded, which represents the current foreign body content in the fiber material 3. In sub-step 94, the current waste composition is recorded, which represents the ratio between foreign bodies and good fibers. In sub-step 95, the current output value is set as the initial value and the current waste composition is set as the waste value, and thus serve as reference values for subsequent decisions in accordance with step 85. Optimization 90 ends at 96. Optimization 90 is preferably fully automatic and is started and monitored by the control unit. In principle, confirmation from the machine operator may be necessary before each optimization run. The respective optimization run can be displayed visually and/or digitally logged.

In order to always be able to provide the most current output value possible, the foreign body detection process 70 with the sub-steps 71 to 77 can be repeated regularly as a background process. The waste composition 80 can also be recorded, in particular permanently.

The inspection device 30 can preferably also be used as a viewing opening through which an operator of the processing machine 1 can look into the filling shaft 2. For this purpose, the opening closure device 31 can have a viewing section 59 in which both the cover element 33 and the separating element 32 are transparent and no components installed in the interior 37 impair the view of the fiber material 3 from the outside. The viewing section 59 is preferably a middle section of the opening closure device 31, which is arranged between the upper section 45 and the lower section 46. If the operator recognizes a change in the proportion of foreign bodies by looking from the outside through the viewing section 59 into the filling space 2 itself, the optimization 90 can also be initiated manually, for example via an application on a mobile device, an operating terminal of the processing machine 1 and/or via a higher-level control unit.

In the 9 an alternative embodiment of the processing machine 1 is shown, which largely corresponds to the previously described embodiments, so that reference is made to the above description with regard to the similarities. The difference is that the processing machine 1 has several, here by way of example two, of the inspection devices 30. The two inspection devices 30 are inserted in the housing openings 27 in the two housing walls 34, 58 arranged opposite one another. By taking pictures of the fiber material surface of the fiber material 3 through the several observation areas 39, a change in the raw material quality can be recorded more precisely and quickly, since several, here two, of the camera devices 38 contribute to achieving the minimum area (sub-step 74) at the same time. The process thus largely corresponds to that in the 6 to 8 shown sequence. Each camera device 38 is assigned one of the evaluation units 57, which analyzes the image data of the assigned camera device 38. The evaluation units 57 transmit their results via an indicated data line to a further or higher-level evaluation unit 60, in which the individual results are summarized. In this way, the required measuring time is shortened, here halved when using two camera devices 38.

In the 10 another embodiment of the inspection device 30 is shown, which largely corresponds to the previously described inspection devices 30, so that reference is made to the above description with regard to the similarities. The only difference is that the camera device 38 of the respective inspection device 30 has two cameras 54`, 54", for example line cameras, each with a lens 55`, 55", instead of one camera 54. Their beam path 44`, 44" is aligned parallel to the respective optical axis 40`, 40". Matrix or area cameras can also be used instead of the line cameras. In this way, the detection width 48 of the camera device 38 can be increased, whereby the measuring time until the minimum area is reached can be shortened. Furthermore, due to the larger detection width 48, the distance between the cameras 54`, 54" and the deflection device 41 can also be reduced. These aspects can be particularly advantageous with wider observation areas 39 and/or with lower housing openings 27, which offer only a small overall height in the extension along the vertical axis Z. In addition, the line of sight of the lenses 55`, 55" to the edges of the individual camera image remains sufficiently steep so that optical errors such as distortion, edge light fall-off, loss of sharpness and the like remain negligible. The lighting device 50 covers the entire detection width 48, which, here by way of example, corresponds to the clear width 49 of the frame 36.

In the 11 another embodiment of the processing machine 1 is shown, which largely corresponds to the previously described embodiments, so that with regard to the similarities, reference is made to the above description is taken. The difference lies in the design of the deflection device 41 and the illumination device 50. The first beam path section 43 is directed obliquely upwards, here for example at an angle of 45 degrees to the observation plane E. The beam path 42 is deflected via the deflection device 41 so that the second beam path section 44 runs parallel to the optical axis 40 of the camera device 38. The illumination device 50 has only the lower illumination element 52, which is directed perpendicular to the observation plane E onto the observation area 39 in order to exclude disturbing light reflections on the transparent separating element 32, which would be found in the image of the camera device 38 or in the image data. The angle of incidence or reflection on the mirror of the deflection device 41 is therefore greater than 45 degrees in each case and can be 67.5 degrees, as shown here as an example. As a result, the deflection device 41 and the camera device 38 can be arranged closer to the separating element 32, so that the opening closure device 31 can be designed to be flatter.

Using the example of the 10 The embodiment shown makes it clear that the camera device 38 can in principle also be arranged high up in the interior 37. The camera device 38 is arranged here between the separating element 32 and the evaluation unit 57. This nesting increases the distance between the camera device 38 and the deflection device 41, thereby increasing the detection width 48. It is understood that all individual features shown in the embodiments are transferable to one another and vice versa. Merely as an example, it is emphasized that the camera device 38 can also be arranged in the embodiments shown in the 1 to 8 shown embodiments with the evaluation unit 57 in the nested arrangement in order to displace the camera device 38 as far upwards as possible; or that the opening closure device 31 can be designed as a rigid window or as a pivoting window; etc.

In the 12 a processing machine 100 according to a further embodiment is shown, which is designed as a mixer and has several of the inspection devices 30. The inspection devices 30 can, as in the 1 to 5 and 9 to 11 shown, so that reference is made to the above description with regard to the similarities. Identical or modified details are provided with the same reference numerals. In the 12 To clarify the orientation of the processing machine 100 in space, a longitudinal direction X, a transverse direction Y and a vertical direction Z are drawn, which are defined in terms of a Cartesian coordinate system assigned to the processing machine 100 and are indicated by corresponding arrows. Terms such as "below", "below", "above" or "above" represent spatial information in relation to the vertical direction Z. The processing machine 100 can be set up on a stationary floor that lies in a horizontal plane spanned by the longitudinal direction X and the transverse direction Y.

The preparation machine 100 has several, here by way of example, ten filling shafts 2 in a row one behind the other. The filling shafts 2 are connected to a channel 101 running above the filling shafts 2, which is connected on the input side via the inlet 4 to an upstream spinning preparation machine (not shown). The fiber material 3, which is usually provided in flake form, is pneumatically introduced into the filling shafts 2 via the inlet 4 and the channel 101. Control elements (not shown) can be provided in a manner known per se between the channel 101 and the individual filling shafts 2 in order to be able to control the filling of the individual filling shafts 2. In a manner known per se, a roller feed and an opening roller can be arranged in the lower part 8 of the respective filling shaft 2, as shown in the 1 and 2 with the reference numerals 9 and 14. Furthermore, a common mixing channel can be arranged below the filling shafts 2, from which the fiber material deposited therein is conveyed in the transport direction T via a pipe system to a subsequent processing machine, for example the one in the 1 and 2 shown cleaner 1, is transported away.

In a front housing wall 34 of the processing machine 100, 2 inspection devices 30 are inserted in the housing openings for each filling shaft. However, it is also possible for the processing machine 100 to have only one of the inspection devices 30 or for only a subset of the filling shafts 2 to be monitored with one of the inspection devices 30. The images captured during operation are evaluated by means of the evaluation units 57 and, if necessary, at least one higher-level evaluation unit 60. The output values can be summarized and averages formed in order to obtain a more representative result. The parallel inspection with the multiple inspection devices 30 can provide statistically more accurate data on the raw material quality, in particular the foreign body content, in a shorter measuring time. In addition, further inspection devices 30 can also be arranged on a rear wall of the processing machine 100, as in the 12 The more inspection devices 30 are provided, the shorter the measuring times can be achieved. For example, two of the inspection devices 30 can be devices 30, one of them at the front and one of them at the back, can be provided, so that the mixer 100, shown here as an example with ten filling shafts 2, can have, for example, twenty of the inspection devices 30.

By summarizing the individual results, here twenty, the evaluation time can be significantly reduced. A central control unit or one of the evaluation units, in particular the higher-level evaluation unit 60, can take over the summarizing of the output values and the transmission to a control unit. The control unit can be assigned to the downstream spinning preparation machine, in particular the cleaner 1, which can make an automatic change to settings on the machine elements that influence the waste separation, for example changing the position of the cleaning elements 15, 16, based on the foreign body content recorded in the mixer 100.

In the 13 a further embodiment of the inspection device 30 is shown, which corresponds to the previously described inspection device 30 to a large extent, so that reference is made to the above description with regard to the similarities. The difference is that the camera device 38 or its optical axis 40 is aligned directly with the observation area 39, so that in this embodiment no device for deflecting the beam path 42, such as the deflection device 41, is provided. The optical axis 40 of the camera device 38 can intersect the observation area 39 or the observation plane E preferably at an angle to an axis running perpendicular to the observation plane E in a range of plus 60 degrees to minus 60 degrees.

Reference symbols

1

Processing machine

2

Filling shaft

3

Fibre material

4

inlet

5

upper part

6

Dust extraction device

7

Exhaust duct

8th

lower part

9

Roller feed

10

Feed roller

11

Feed roller

12

Feed roller

13

Feed roller

14

Opening roller

15

Cleaning element

16

Cleaning element

17

Top circle

18

set

19

Extractor hood

20

Extractor hood

21

Waste stream

22

Waste sensor device

23

sensor

24

sensor

25

Waste channel

26

Housing

27

Housing opening

28

Photoelectric barrier

29

Pressure sensor

30

Inspection facility

31

Opening locking device

32

Separating element

33

Cover element

34

Housing wall

35

Outside

36

Frame

37

inner space

38

Camera device

39

Observation area

40

optical axis

41

Diversion device

42

Beam path

43

Beam path section

44

Beam path section

45

upper section

46

lower section

47

surface

48

Detection width

49

clear width

50

Lighting device

51

Lighting element

52

Lighting element

53

Light source

54

camera

55

lens

56

Data line

57

Evaluation unit

58

Housing wall

59

Viewing section

60

Evaluation unit

61

Joint remedies

62

Locking device

63

Direction

65

begin

70

Step

71..76

Substep

77

End

80, 85, 90

Step

91

begin

92

Optimization run

93..95

Substep

96

End

100

Processing machine

101

Channel

A

Direction

E

Observation level

F

Fill level

T

Transport direction

X, Y, Z

Longitudinal, transverse, vertical direction

QUOTES INCLUDED IN THE DESCRIPTION

This list of documents listed by the applicant was generated automatically and is included solely to provide the reader with better information. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions.

Cited patent literature

• EP 3951032 A1 [0003]
• DE 10349407 B4 [0016]
• DE 102012012254 A1 [0043]

Claims (10)

Method for detecting foreign bodies in fiber material (3) that is accommodated in a filling shaft (2) of a processing machine (1; 100), in particular a spinning preparation machine, wherein the processing machine (1; 100) - has a housing (26) with a housing opening (27) through which the filling shaft (2) can be viewed from the outside, and - an inspection device (30) that closes the housing opening (27) and comprises a separating element (32) with a transparent observation area (39) and at least one camera (54) that looks through the observation area (39) into the filling shaft (2), and wherein the method comprises the following repetitive steps: - recording (72) images of the fiber material (3) passing by the observation area (39) using the at least one camera (54); - Evaluating (73) the recorded images by at least one evaluation unit (57) which is connected to the at least one camera (54) and is configured to determine a foreign body content of the fiber material (3) and provides the foreign body content as an output value; - Comparing (85) the output value with a predetermined and/or previous initial value; - Carrying out an optimization run (92) in which a position or rotational speed of at least one cleaning element (15, 16) for separating waste material from the fiber material (3) is automatically changed if the output value deviates from the initial value, wherein a current waste composition of the separated waste material comprising foreign bodies and good fibers in a waste strand (21) downstream of the at least one cleaning element (15, 16) is determined (80) by means of a waste sensor device (22) by means of at least one optical sensor (23, 24). Procedure according to Claim 1 , characterized in that the method, in particular before carrying out the optimization run, further comprises at least one of the following steps: - determining (80) the current waste composition by the at least one waste sensor device (22) if the output value deviates from the predetermined and/or previous output value; - comparing (85) the current waste composition with a predetermined and/or previous waste value. Procedure according to Claim 2 , characterized in that the step of the optimization run (92) is carried out if the output value deviates from the predetermined and/or previous output value and if the current waste composition deviates from the predetermined and/or previous waste value. Method according to one of the Claims 1 until 3 , characterized in that a cover element (33) is arranged on the separating element (32), wherein an interior space (37) is formed between the separating element (32) and the cover element (33), in which the at least one camera (54) is arranged. Procedure according to Claim 4 , characterized in that the at least one camera (54) is arranged and aligned such that an optical axis (40) of the at least one camera (54) is aligned at least substantially parallel to the observation plane (E), and that a deflection device (41) which deflects a beam path (42) emanating from the observation area (39) towards the at least one camera (54) is arranged in the interior (37) of the opening closure device (31). Method according to one of the Claims 1 until 4 , characterized in that the at least one camera (54) is directed towards the observation area (39). Method according to one of the Claims 1 until 6 , characterized in that a dynamic pressure in the filling shaft (2) is measured, wherein with the aid of the measured dynamic pressure the output value provided by the at least one evaluation unit (57) is corrected to a characteristic value independent of the dynamic pressure (75). Method according to one of the Claims 1 until 7 , characterized in that the inspection device (30) is retrofitted by inserting the inspection device (30) into an already existing housing opening (27) of the processing machine (1; 100), through which the filling shaft (2) can be viewed from the outside. Method according to one of the Claims 1 until 8th , characterized in that the processing machine (1; 100) has a plurality of the housing openings (27), wherein one of the inspection devices (30) is inserted in at least a subset of the housing openings (27). Method according to one of the Claims 1 until 9 , characterized in that a dosing device (9) is arranged in a lower part (8) of the filling shaft (2) and is configured to remove the fiber material in a dosed manner from the filling shaft (2).

Images