Method for detecting foreign bodies in fiber material

Abstract

The invention relates to a method for detecting foreign bodies in fiber material (3) which is received in a filling shaft (2) of a preparation machine (1; 100), in particular a spinning preparation machine. The preparation machine (1; 100) has a housing (26) with a housing opening (27), via which the filling shaft (2) is visible from the outside, and an inspection device (30) which closes the housing opening (27) and which comprises a separating element (32) with a transparent monitoring region (39) and at least one camera (54) which has a view into the filling shaft (2) through the monitoring region (39). The method has the following repeating steps: capturing (72) images of the fiber material (3) passing by the monitoring region (39) by means of the at least one camera (54); analyzing (73) the captured images by means of at least one analyzing unit (57) which is connected to the at least one camera (54) and is configured to determine the content of foreign bodies in the fiber material (3) and provide the foreign body content as an output value; comparing (85) the output value with a specified and / or previous starting value; and carrying out an optimization run (92) in which the position or speed of at least one cleaning element (15, 16) for removing waste material from the fiber material (3) is automatically modified if the output value deviates from the starting value, wherein the current waste composition of the separated waste material, comprising foreign bodies and reusable fibers, is determined (80) in a waste section (21) connected downstream of the at least one cleaning element (15, 16) by means of a waste sensor device (22) using at least one optical sensor (23, 24).

Description

[0001] Title: Method for detecting foreign bodies in fiber material

[0002] Description

[0003] The present invention relates to a method for detecting foreign bodies in fiber material accommodated in a hopper of a processing machine, in particular a spinning preparation machine. The processing machine comprises an inspection device with a separating element having a transparent observation area and at least one camera that looks through the observation area into the hopper.

[0004] In a spinning mill, the fiber quality purchased from a fiber bale, which may be made of cotton, polyester, blended 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 blowroom. Quality fluctuations in the bale feed are often not detected during the ongoing processing, and necessary adjustments to machine settings to always achieve 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 interfering particle content is a common parameter. Foreign bodies present in the pressed fiber bales include, for example, plant components such as stems, leaves, seeds (commonly referred to as "trash") or packaging residues such as fabrics, textiles, films, plastic straps, and the like.Of these foreign bodies, only plant foreign bodies (trash) are included in the classified raw material parameters of the purchased bales. Due to their comparatively low frequency, the other components are barely detectable through conventional sampling with laboratory analysis equipment. Furthermore, the actual content is subject to considerable fluctuations. However, even with the content of plant components, there are such significant deviations between the actual raw material quality and the classified values ​​that, with regard to the quality requirements of the final product, as well as with regard to energy consumption and resource-efficient handling of the raw material, a change in the processing machinery settings would be necessary.However, readjusting the machines due to fluctuations in the quality of the raw material is not feasible in practice, since the available measurement methods using laboratory analysis are too slow to generate a corresponding control variable in a timely manner, i.e. while the material is still being processed, or would involve considerable effort.

[0005] EP 3 951 032 A1 discloses a device with a camera for detecting interfering particles in fiber material collected in a hopper of a spinning preparation machine. The camera is positioned at a maximum angle of + / - 30 degrees to a perpendicular to the fiber surface.

[0006] 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 process can be made in the event of a changing foreign body content during the ongoing processing process.

[0007] 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 repeating steps: Recording images of the fiber material passing by the observation area by means of the at least one camera; Evaluation of 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; Comparison of 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;

[0008] For the sake of clarity, 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 as "the camera," "the evaluation unit," "the cleaning element," or "the sensor," respectively, whereby this continues to refer to exactly one of the respective components or a plurality of the respective components. Where the exact number is important, this will be indicated at the appropriate point.

[0009] The advantage is that by repeatedly recording and analyzing images of the fiber material passing through the observation area, quality fluctuations or fluctuations in the foreign body content in the bale feed or the fiber material collected in the filling chamber can be detected early on, and adjustments to machine settings can be made automatically. Manual interventions, such as taking fiber samples for laboratory testing, are eliminated, allowing the fiber material in the processing machine to be visually inspected with minimal effort and enabling optimization of the processing of the fiber material during the ongoing processing process. The camera looks from the outside through the transparent observation area into the filling chute and can visually inspect the fiber material passing through the observation area and its surface.The fiber material thus remains in the hopper, and the fiber processing process is not disrupted by the externally mounted inspection device. If the analysis of the image data shows that the output value deviates from the initial value because the raw material quality or foreign body content has changed, the position or rotation speed of the cleaning element can be readjusted. This is done during the optimization run, during which the waste sensor device determines the waste composition in the separated waste material. The inspection device thus determines the foreign body content of the fiber material in the hopper, and the waste sensor device determines the waste composition in the waste stream downstream of the cleaning element.

[0010] The initial value can correspond to a foreign body content for which the cleaning element is set in order to achieve 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, readjustment may be necessary to maintain the best possible cleaning efficiency despite the changed raw material quality. The optimization run thus serves to automatically adjust the cleaning efficiency as the foreign body content changes. Furthermore, the initial value after the optimization run has been performed can be set equal to the value of the output value on which the optimization run was based. The evaluation unit then determines a new, i.e. current, output value, which is in turn compared with the initial value.If the new output value deviates from the initial value, which may 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 by the operator or machine operator. For example, when changing batches, it may be necessary to use a predefined initial value in order to initially adjust the cleaning element to the purchased bale quality. When raw cotton is used as the starting product, the foreign body content can typically range from 2 to 6 percent (mass ratio to raw cotton). When waste is fed in, the foreign body content can even be higher.

[0011] Depending on the operator's requirements for purification efficiency, a defined deviation of the output value from the initial value may be tolerable. This has the advantage that an optimization run is not performed in the case of minor quality fluctuations. For example, a percentage deviation of the output value of, say, 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, whereby the optimization run is only performed if the output value lies outside the range.

[0012] Furthermore, the method may comprise at least one of the following steps, which may be performed, for example, before performing 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.

[0013] Furthermore, the process can perform the optimization run 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 regarding the degree of good fiber removal, 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 generally possible. The waste value can also be a range of values, with the optimization run only being performed if the initial value and / or the output value lie outside the respective value range.

[0014] The cleaning element can be arranged on the processing machine itself or on a spinning preparation machine upstream or downstream of the processing machine. If several cleaning elements are provided, they 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 which 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 downstream spinning preparation machine can also be a processing machine according to the invention or it can be a spinning preparation machine which is not equipped with its own filling chute or is not equipped with the inspection device.

[0015] In a further development, several of the machines can be combined into a single 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, provided they have a filling chute that is visible from the outside, are each equipped with at least one of the inspection devices. In this way, the quality characteristics of the fiber material, in particular the foreign matter content, can be analyzed at several process points within the system. This allows the machines of the system to be automatically adapted to changes in the raw material quality, depending on the recorded raw material quality.

[0016] The fiber material usually moves at a slow transport speed in the filling chute, while the camera is held stationary. Preferably, the fiber material flows through the filling chute from top to bottom, following the direction of gravity. The fiber material can sometimes be briefly accumulated in the filling chute during operation of the processing machine. In particular, a dosing device is arranged on the underside of the filling chute and configured to remove the fiber material from the filling chute in doses. The dosing device can, for example, be a roller feeder and / or an opening roller. The material transport speed in the filling chute, i.e. the transport speed, depends on several factors, such as the production rate, the material dissolution, the conveying pressure, etc., whereby the transport speed can range from a few millimeters per minute to a few centimeters per minute.The transport speed is usually in the range of 20 to 800 millimeters per minute.

[0017] Due to the low transport speed, a large number of images can be captured 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 produce at least one output value. In order to generate an output value or measured value from the image data that reliably and statistically represents the foreign body content in the fiber material, it has proven advantageous if a minimum area of ​​the fiber material is captured and evaluated by the camera device. Very high accuracy was achieved when the minimum area was more than 2 square meters and, more preferably, at least approximately 3 square meters. More than 3.5 square meters did not show any significant improvement in terms of accuracy, but did lead to longer evaluation times. The minimum area can be a manually adjustable value that the operator of the processing machine can adapt to their own quality specifications.In order to capture 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, as too high an image recording frequency can result in multiple counts of the foreign bodies visible through the observation area. The time until the minimum area is captured can also be reduced by using several of the inspection devices that capture images of the fiber material at several points on the processing machine. If the processing machine has several of the filling chutes, such as a mixer with several filling chutes or chambers, the inspection devices can be arranged at each filling chute and their images can each contribute a portion of the minimum area.If several of the inspection devices are arranged on 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 detected multiple times.

[0018] The waste sensor device is known, for example, from patent DE 103 49 407 B4. 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, thus also the waste composition, and can distinguish between desired waste (foreign bodies) and undesired waste (good fibers). The cleaning element, for example, in a pre-cleaner, can be an opening roller whose rotational speed can be changed. Furthermore, the cleaning element can change the opening width of a separation grid by changing its position. Also possible are adjustable separation knives that attach tangentially to an opening roller, adjustable wings, suction hoods, etc.In addition, the processing machine can be equipped with a variety of other adjustable cleaning elements.

[0019] For example, let's assume that, during ongoing operation of the processing machine, the raw material quality deteriorates and, at the same time, the cleaning efficiency of the processing machine decreases. Without the inspection device, the decline in raw material quality would go unnoticed. Another scenario would be that the amount of foreign matter removed at the cleaning points decreases, which could be determined by measuring the waste composition. However, this does not allow for the determination of whether the raw material has become cleaner or whether one of the processing machines, particularly the cleaner, needs to be re-optimized. The optimal setting therefore depends on the material and the contamination and can be adjusted during operation if the properties of the raw material change.

[0020] The waste sensor device can be configured to move the at least one cleaning element into 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 from the waste sensor device are recorded and evaluated. The optimization run can be ended 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 CL-U universal cleaner 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 closed here.can be completely or partially closed. In this way, little or no cleaning effect is achieved in the first end position, and while the cleaning effect may be better in the second end position, too many good fibers may also end up in the waste, along with the foreign matter. Instead of a full optimization run, in which the first end position is first approached, it is also possible to check, starting from the current operating position of the cleaning element, by slightly adjusting the cleaning element to see whether even small adjustments can improve the separation efficiency.

[0021] 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.

[0022] 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, which deflects a beam path emanating from the observation area towards the camera, is arranged in the interior space formed between the separating element and the cover element. The camera thus views the observation area indirectly. 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, whereby the detection range can be increased. By "at least substantially parallel" is to be understood 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 is possible.If the parallelism is deviated, the intersection point of the optical axis with the observation plane may be outside the observation area, preventing the camera from directly viewing the observation area. The camera is preferably positioned and aligned so that the optical axis runs parallel to the observation plane.

[0023] The deflection device can have a reflective surface. The angle of incidence or reflection between the beam path and a surface normal of the reflective surface can each be 45 degrees. 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 each be greater than 45 degrees, 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 each also be less than 45 degrees and in particular greater than 15 degrees.While this results in a somewhat greater installation depth for the inspection device, it also results in a greater distance between the camera and the observation area, which can increase the camera's detection range. The deflection device can comprise at least one deflection element, in particular a mirror. Alternatively to the mirror or as an additional deflection element, an optical fiber or the like can be provided.

[0024] 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. Thus, the camera looks directly at the observation area, so that in this embodiment, no device for deflecting the beam path, such as a 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.

[0025] For all designs, it is equally true that a dynamic pressure can be measured in the hopper, whereby the output value provided by the evaluation unit can be corrected to a parameter that is independent of the dynamic pressure using the measured 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 material layer will present a small number of foreign bodies in the hopper to the camera. If, on the other hand, the material in the hopper is compacted by the application of transport air at a higher pressure, considerably more foreign bodies will be visible in the observation area or in the image, and thus in the same area. Thus, fluctuating dynamic pressure can distort the recording of the foreign body content.A pressure sensor for measuring the back 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 fill level. To specify the maximum fill level, a light barrier or a light sensor can be arranged in the at least one filling shaft. The maximum fill level can be determined by an installation height of the light barrier or the light sensor.

[0026] Furthermore, the method can comprise 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 is visible 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. Thus, a conventional processing machine, at least one housing opening of which is equipped with the conventional viewing or access opening, 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 upon initial delivery of the processing machine. However, it is also possible to create an opening in the processing machine's housing specifically for the inspection device.

[0027] Depending on the application, the inspection device can be designed as a fixed or openable, particularly pivoting, 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, to remove a portion of the collected fiber material. When the inspection device is closed, the inspection device seals the housing opening, particularly 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.Preferably, the external dimensions of the inspection device are selected such that the inspection device can be inserted into the existing housing opening instead of the maintenance window. In particular, the inspection device, in particular the opening closure device, can have an external width between 200 millimeters and 600 millimeters and an external height between 400 millimeters and 1200 millimeters. Preferably, the external width is in a range between 300 millimeters and 500 millimeters, and the external height is in a range between 600 millimeters and 1000 millimeters.

[0028] The separating element and the cover element form an opening closure, which can have 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. For operation of the inspection device, it can be connected to an electrical supply, in particular of the processing machine. Furthermore, means for data transmission can be provided. For example, the camera can have an interface for connection to the evaluation unit and / or the control unit. The inspection device can comprise the evaluation unit, which can in particular be accommodated 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.

[0029] The camera and the optional deflection device are preferably housed entirely within the interior of the opening / closure device. The separating element is designed to be translucent, or transparent, at least in the observation area, so that the camera can capture images 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. Advantageously, 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 / is designed to be located outside the hopper. The separating element separates the interior from the hopper of the processing machine, so that the camera has no contact with the fiber material and is accordingly protected.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 protectively covers the camera arranged between the separating element and the cover element from the outside. Preferably, the cover element and the separating element are firmly connected to one another. The separating element can 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 unhindered passage of the fiber material. 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 partition wall. The cover element can be designed, for example, in the shape of a trough or bowl to form the interior.The lid element and the divider element.

[0030] A lighting device for illuminating the fiber material conveyed past the observation area can be arranged in the interior of the opening closure device. This allows the fiber material conveyed past the observation area in the filling chute of the processing machine to be illuminated with incident light. The lighting device can extend across 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 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 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 recorded 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 respective 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 perpendicular to the observation plane. This is particularly advantageous when the beam path between the observation area and the optional deflection device runs obliquely to the surface normal.

[0031] The observation area can be illuminated by the illumination device at least when an image is being captured. In a further development, the observation area can be continuously illuminated by the illumination device. This can be advantageous, among other things, when the camera is a line-scan camera. Likewise, flash operation, in which the illumination device generates flashes, can be advantageous when alternating illumination with light of different wavelengths is required, or when the movement of the fiber material along the observation area is so slow that the light can be switched off between individual image captures.

[0032] 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 space, the distance of the camera from the observation area, and the like. Preferably, exactly one or two cameras are provided. To increase the detection width of the respective camera, it can be placed as high up as possible in the interior space. Furthermore, the focal length of the lens can be reduced. However, this can lead to a large viewing angle towards the edge of the detection area, which can be associated with optical disadvantages. If several cameras are used, they can be arranged next to one another in the direction of the width of the dividing element and, in particular, at a distance from one another. The detection ranges of neighboring cameras can also overlap to ensure seamless coverage of the observation area.

[0033] The camera, together with the evaluation unit, also called an image evaluation computer, can form a camera device. The camera device can accordingly comprise precisely 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 space between the cover element and the separating element. However, it is also fundamentally possible for the evaluation unit to be arranged outside the interior space, for example, on or in the processing machine.

[0034] The camera can be a line-scan camera. This enables a large detection width or detection over a wide 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-scan camera records the image line by line. The individual image lines can be combined into a continuous image by the evaluation unit. The fiber material moves past the observation area, and the camera device is held stationary at the opening closure device, i.e., the camera remains stationary. The detection area, or image field at the moment of recording, is a slit the width of the desired image, which preferably corresponds at most to the width of the separating element.As a result, the line scan camera requires only 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 as a whole can be designed to be flat. In addition, the observation area can be narrow in height and correspondingly wide in width. To avoid optical disadvantages caused by large viewing angles at the edges, it is advantageous if the viewing angle from the camera center to the edges of the image is a maximum of 15°. With 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.

[0035] 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.

[0036] 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 scan camera 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, toward which the cameras can be aligned.

[0037] When configured with the deflection device, the opening closure device can have an upper section and a lower section spaced from the upper section along the optical axis. The camera can be arranged in the upper section and the observation area as well as 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 configured without the deflection device, the opening closure device can have a section in which the camera and the observation area are located. To shield the observation area from ambient or extraneous light, the cover element can be opaque in the section (particularly the lower or upper section) in which the observation area is located. This prevents disruptive light reflections in the observation area.

[0038] The opening closure device can serve as a support for additional 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.

[0039] Furthermore, the opening closure device can have a viewing section located above and / or below the observation area. In other words, the observation area, in which the cover element can be designed to be opaque, lies 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 port through which a human operator can look into the filling chute of the processing machine from the outside in order 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 transparent and can be made, for example, from a transparent glass or plastic material.At the level of the observation area, particularly in the lower section of the opening closure device, the cover element made of the transparent material can be foiled, painted or the like in order to shield the observation area from disturbing external light.

[0040] Furthermore, the processing machine can have a plurality of housing openings, with one of the inspection devices being inserted into at least a portion of the housing openings. Furthermore, two of the inspection devices can be provided per filling shaft, which can be arranged facing each other on a front and a rear side of the processing machine.

[0041] The preparation machine can be a spinning preparation machine, in particular a bale opener, for example a Trützschler Universal Bale Opener BO-U, a cleaner, for example a Trützschler Universal Cleaner CL-U, an opener, for example a Trützschler Universal Opener TO-U, a mixer, for example a Trützschler Universal Mixer MX-U, a flock mixer, for example a Trützschler T-Blend, a card, for example a Trützschler TC21, and the like. Furthermore, the preparation machine can be from the field of nonwovens production, such as an opener, for example a Trützschler Fine Opener TBL-FB or TBL-FO, a mixing chamber, for example a Trützschler TBL-BB, a carding machine, for example a Trützschler TWF-NC, and the like.

[0042] Further features and advantages of the invention will become apparent from the following description of preferred embodiments. Features that are essentially or functionally identical or similar are provided with the same reference numerals. They show:

[0043] Figure 1 shows 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;

[0044] Figure 2 is a partially sectioned side view of the processing machine;

[0045] Figure 3 is an enlarged partial view of the processing machine in a schematically simplified sectional view;

[0046] Figure 4 is an enlarged partial view of the processing machine in the area of ​​the inspection device, with the camera set to a first focal length; Figure 5 is the enlarged partial view from Figure 4, with the camera set to a second focal length;

[0047] Figure 6 is a schematic representation of a flow chart of the processing machine in automatic operation;

[0048] Figure 7 is a schematic representation of a sub-step of the flow chart of Figure 6 relating to the determination of a foreign body content in the fibre material;

[0049] Figure 8 is a schematic representation of a further sub-step of the flow chart of Figure 6 relating to the execution of an optimization run;

[0050] Figure 9 is 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;

[0051] Figure 10 is an enlarged partial view of the processing machine in the area of ​​an inspection device according to an alternative embodiment with two cameras;

[0052] Figure 11 is an enlarged partial view of the processing machine according to yet another embodiment in a schematically simplified sectional view;

[0053] Figure 12 is a side view of a processing machine according to a further embodiment of the invention; and

[0054] Figure 13 is 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.

[0055] Figures 1 and 2 show a processing machine 1 according to a first embodiment of the present invention, which is designed as a cleaning machine, i.e. a cleaner. Further details and possible modifications are shown in Figures 3 to 5. To clarify the orientation of the processing machine 1 in space, a longitudinal direction X, a transverse direction Y and a vertical direction Z are shown in the figures, which are defined in the sense 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 with reference 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.

[0056] Figure 1 shows that the processing machine 1 has a filling chute 2. The filling chute 2 is connected to an inlet 4, through which fiber material 3, usually provided in flake form, can be pneumatically introduced from an upstream processing machine, for example a mixer shown in Figure 12, here the Trützschler Universal Mixer MX-U. A dust removal device 6, which separates dust and transport air from the fiber material 3, is arranged in an upper part 5 of the filling chute 2. 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 chute 2, where it is accumulated during operation of the processing machine 1.For this purpose, a dosing device, here in the form of a roller feed 9, is arranged in the lower part 8. This roller feed 9, as an example, has two slowly rotating feed rollers 10, 11, whose rotational directions are opposite to each other, and below the feed rollers 10, 11, two slowly rotating feed rollers 12, 13, whose rotational directions are opposite to each other. The feed rollers 12, 13 form the bottom of the filling shaft 2, below which an opening roller 14 is arranged.

[0057] A first cleaning element 15 and a second cleaning element are assigned to the opening roller 14, one after the other in its direction of rotation. Such an arrangement is described in the applicant's published patent application DE 10 2012 012 254 A1, which is incorporated herein by reference. The first cleaning element 15 is displaceable 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 is conveyed into a waste line 21 via suction hoods 19, 20.In the direction of rotation of the opening roller 14, behind the second cleaning element 16, there is a piping system through which the cleaned fiber material 3 can be transported to a downstream processing machine (not shown), for example, a foreign matter separator such as the Trützschler SP-FPU, T-Scan TS-T3, or T-Scan TS-T5. The transport direction of the cleaned fiber material 3 to the downstream processing machine is indicated by arrow T in Figure 1.

[0058] Figure 2 shows that the waste material extracted into the waste stream 21 via the extraction hoods 19, 20 is guided past a waste sensor device 22. The waste sensor device 22 has an optical measuring device, each with a sensor 23, 24, in particular a brightness sensor, for each extraction hood 19, 20, which looks into the respective extraction hood 19, 20 through a transparent partition. The sensors 23, 24 can be used to detect the waste material transported away via the extraction hoods 19, 20 through a waste channel 25 of the waste stream 21 in order to detect good fibers in the waste stream within the passing fibers. 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.

[0059] Above the roller feed 9, a housing opening 27 is formed in a housing 26 of the processing machine 1 enclosing the filling chute 2. A light barrier 28 or a light sensor connected to a machine control system (not shown) is arranged above the housing opening 27 and serves as a fill level limiter. As soon as the fill level F of the fiber material 3 in the filling chute 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 determines the maximum fill level Fmax. Furthermore, a pressure sensor 29 is arranged above the light barrier 28 in the filling chute 2. This pressure sensor can be designed as a differential pressure sensor to measure the difference between the room pressure prevailing in the filling chute 2 and the ambient pressure prevailing outside the filling chute 2.This makes it possible to determine the influence of the dynamic pressure due to the transport air flowing into the filling chute 2, which presses onto 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 design and function of this inspection device are explained in detail below. Figures 1 and 2 show 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 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.

[0060] Figure 3 shows that the inspection device 30 has an opening closure device 31 comprising a separating element 32 and a cover element 33. The separating element 32 is plate-shaped and can be flush with a housing wall 34 of the filling shaft 2 surrounding the housing opening 27. During operation of the processing machine 1, the fiber material 3 moves or sweeps 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, which is provided with the reference numeral 63. Furthermore, the opening closure device 31 can have a frame 36 enclosing 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 therefrom and comprises the unit consisting of the separating element 32 and the cover element 33, in order to be able to remove this unit easily 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 conventional manner to seal the housing opening 27 and the interior space 37 against dust and moisture.

[0061] A camera device 38 is arranged in the interior space 37 of the opening closure device 31 in order to be able to record images of the fiber material 3, which passes in the filling shaft 2 past 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, wherein, 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 space 37 of the opening closure device 31, which deflects a beam path 42 emanating from the observation area 39 towards the camera device 38.The deflection device 41 comprises, here by way of example, a mirror with a reflective surface 47. The angle of incidence and reflection is 45 degrees, respectively, so that the beam path 42 is deflected by 90 degrees. Figure 3 shows 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.

[0062] 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, which is 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 at most to a clear width 49 of the frame 36.In Figures 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 each position. A guide device (not shown), which may comprise, for example, a rail, rod, a plate with a hole pattern, or the like, can be provided in the interior space 37 to align the camera device 38 and adjust the inspection width via the distance from the deflection device 41.

[0063] To illuminate the fiber material 3 passing 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 strip-like 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, as an example here, in a range between 20 degrees and 80 degrees. To shield the observation area 39 from ambient or extraneous light, the cover element 33 can be designed to be opaque in the lower section 46.

[0064] The camera device 38 has a camera 54, here for example a line scan camera, with a lens 55, although in principle an area scan 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 by 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 detect 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.

[0065] 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 conventional manner, into which an inspection device 30 could in principle also be inserted. The inspection device 30 can have an interface to enable the inspection device 30 to be connected to an electrical supply system and / or a bus system, in particular a fieldbus, 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, for example, 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 controller that communicates with a plurality of control units of other processing machines.

[0066] During operation of the processing machine 1, the fiber material 2 is pneumatically transported via the inlet 3 into the filling chute 2. The transport air is discharged via the dedusting device 6, and the fiber material 3 collects in the lower part 8 of the filling chute 2. Due to the slow-operating roller feed 9, it accumulates in the filling chute 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 briefly that the fill level F is below the observation area 39. To prevent images from being taken at this time, fill level sensors, such as an additional light barrier, light scanner, and the like, can be provided.

[0067] Figure 6 shows a possible flow chart for automatic operation of the processing machine 1. With start 65, the cleaning elements 15, 16 are already optimally adjusted for a predetermined starting value by means of an initial optimization run. The predetermined starting value can correspond to a manually entered foreign body content determined by the operator based on the purchased or tested raw material quality. The optimization run can be carried out during ongoing operation of the processing machine 1 by continuing to drive the roller feed 9 and the opening roller 14 in rotation. During the optimization run, the optical sensors 23, 24 of the waste sensor device 22 check the waste material extracted via the extraction hoods 19, 20 for its waste composition. At the start of each optimization run, the first cleaning element 15 can initially be moved to a first position in which the cleaning point orCleaning opening is closed. The degree of foreign matter separation will initially be low in the first position. The first cleaning element 15 can then be moved along the double arrow A and gradually open the cleaning opening, whereby the proportion of foreign matter will increase. From a certain point onwards, the proportion of good fibers will continue to increase in relation to the proportion of foreign matter. The first cleaning element 15 is then moved to the position in which the ratio between foreign matter and good fibers was most favorable in this optimization run. The ratio between foreign matter and good fibers resulting from the optimization run is saved as the waste value.Depending on 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 be automatically adjusted until the desired waste quality is achieved. The optimization run performed on the basis of the initial value thus optimizes the cleaning efficiency of the processing machine 1. After the start 65 of automatic operation, the current or actual foreign body content in the fiber material 3 is recorded or monitored in step 70. Step 70 comprises various substeps, which are shown in the flowchart in Figure 7.After the foreign body detection has been started 71, the camera device 38 takes an image of the fiber material 3 passing behind the observation area 39 in sub-step 72, with the illumination device 50 illuminating the observation area 39 using the incident light method during the recording. 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 is evaluated using image processing methods with regard to the number, frequency, and / or total area of ​​foreign bodies in the fiber material 3. Foreign bodies such as stems, leaves, or general "trash" particles typically appear as dark spots on the otherwise cream- to white-colored fiber material 3. Because almost binary states exist, segmentation between the sought-after foreign bodies against the light background of the fiber material 3 is possible, for example, using threshold operations.A classic decomposition of the scene into objects with characteristics such as size, area, contour, etc. can follow. The foreign matter content can be determined by counting the dark objects or by accumulating the area. Further, size histograms or a classification of the objects into groups such as trash, stems, leaves, etc. can be performed.

[0068] In sub-step 74, a query is made as to 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. Very high 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 scan camera 54 compared to the minimum area of, for example, 90 square millimeters, further images are captured 72 and evaluated 73 until the defined minimum area has been reached.

[0069] In order to be able to react as quickly as possible to the changing foreign body content 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 has only 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 enlarged, 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 capture 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 recorded at an exemplary transport speed of 120 to 360 millimeters per minute with an image recording frequency of 13 to 80 Hertz. Assuming a capture or image area of ​​an image from the camera device 38 of 90 square millimeters, the measuring time to reach the minimum area of ​​3 square meters would be 14 minutes. Higher transport speeds, which can be achieved through higher production rates, thus enable a higher image recording frequency, whereby the minimum area can be captured more quickly. When evaluating the images, the evaluation unit 57 thus considers images constructed line by line, as is usual for line scan cameras, and evaluates them 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 foreign body content in the fiber material 3.

[0070] In sub-step 75, the evaluation unit 57 takes into account the dynamic pressure in the filling chute 2 measured by the pressure sensor 29 during image evaluation. The transport air flowing into the filling chute 2 always leads to a certain compaction of the fiber material 3 in the filling chute 2, which can influence the accuracy of the output value. In order to minimize and, if possible, eliminate this influence, the pressure sensor 29 is coupled to the evaluation unit 57. Using 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 recording of the foreign body content ends at 77.The foreign body detection process according to substeps 71 to 77 can be repeated regularly. Several detection processes can also run simultaneously with a time offset, allowing a current foreign body content to be provided at shorter intervals using the updated output value.

[0071] According to the flowchart shown in Figure 6, step 70 is followed by 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, permanently monitor the waste composition, so that step 80 can also run concurrently 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.

[0072] Based on the corrected output values ​​and the waste composition, a decision can be made in step 85 as to whether optimization of the cleaning of processing machine 1 is necessary ("yes"). If none of the following criteria is met, the cleaning elements 15, 16 are currently optimally adjusted and no optimization is necessary at this time ("no"), so the method continues with the loop comprising steps 70, 80, and 85.

[0073] The optimization is carried out in step 90 if one of the following criteria is met: if the output value, in particular the corrected one, 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 deviates from the waste value set in the previous or initial optimization run and is in particular outside a predeterminable tolerance range around the waste value;the waste value set in the initial optimization run has remained the same or at least lies within a predefined tolerance range around the waste value, but the particularly corrected output value has changed over time because the output value lies outside the predefined tolerance range, a sudden increase in the output value was detected or a continuous increase or decrease is detected when considering the integral over time; if both the particularly corrected output value lies outside the predefined tolerance range around the initial value in comparison with the initial value and the waste composition or waste quantity lies outside the predefined tolerance range around the waste value.

[0074] The optimization 90 comprises various sub-steps, which are shown in the flow chart in Figure 8. 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, during this time, the changing waste composition is monitored by the waste sensor device 22. Depending on specifications stored in the control unit or specified by the operator of the processing machine 1, the machine units influencing the waste composition, here the cleaning elements 15, 16, are automatically adjusted until the desired waste quality for the recorded output value, which reflects the current foreign body content, is achieved.Instead of the full optimization run 92, in which the first position is initially approached, it is also possible to check, starting from the previously set operating point, by slightly adjusting the cleaning elements 15, 16, whether an improvement in the separation efficiency can be achieved by 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 according to step 85. The optimization 90 ends with 96. The optimization 90 is preferably fully automatic and is started and monitored by the control unit.In principle, confirmation from the machine operator may be required before each optimization run. The respective optimization run can be displayed visually and / or digitally logged.

[0075] In order to always provide the most up-to-date output value possible, the foreign body detection process 70, comprising substeps 71 to 77, can be repeated regularly as a background process. Likewise, the waste composition 80 can be recorded, in particular, permanently.

[0076] 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-closing 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 central section of the opening-closing device 31, which is arranged between the upper section 45 and the lower section 46.If the operator detects a change in the foreign body content by looking from the outside through the viewing section 59 into the filling chamber 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.

[0077] Figure 9 shows an alternative embodiment of the processing machine 1, which largely corresponds to the previously described embodiments, so that with regard to the similarities, reference is made to the above description. 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 into the housing openings 27 in the two oppositely arranged housing walls 34, 58. By recording images of the fiber material surface of the fiber material 3 through the multiple observation areas 39, a change in the raw material quality can be detected more precisely and quickly, since several, here two, of the camera devices 38 contribute simultaneously to achieving the minimum area (sub-step 74). The process thus largely corresponds to the process shown in Figures 6 to 8.Each camera device 38 is assigned one of the evaluation units 57, which analyzes the image data of the associated 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 measurement time is shortened; in this case, it is halved when two camera devices 38 are used.

[0078] Figure 10 shows a further embodiment of the inspection device 30, which largely corresponds to the previously described inspection devices 30, so that with regard to the similarities, reference is made to the above description. The only difference is that instead of one camera 54, the camera device 38 of the respective inspection device 30 has two cameras 54', 54", for example line scan cameras, each with a lens 55', 55". Their beam path 44', 44" is aligned parallel to the respective optical axis 40', 40". Matrix or area scan cameras can also be used instead of the line scan 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 for wider observation areas 39 and / or for lower housing openings 27, which offer only a low overall height along the vertical axis Z. Furthermore, 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, peripheral light falloff, loss of sharpness, and the like remain negligible. The illumination device 50 covers the entire detection width 48, which, here by way of example, corresponds to the clear width 49 of the frame 36.

[0079] Figure 11 shows a further embodiment of the processing machine 1, which largely corresponds to the previously described embodiments, so that reference is made to the above description regarding the similarities. 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 upward, here, for example, at an angle of 45 degrees to the observation plane E. The beam path 42 is deflected by 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 eliminate disruptive light reflections on the transparent separating element 32, which would be reflected in the image of the camera device 38 or in the image data. The angle of incidence or reflection at the mirror of the deflection device 41 is thus greater than 45 degrees and can be 67.5 degrees, as shown here by way of example. This allows the deflection device 41 and the camera device 38 to be arranged closer to the separating element 32, so that the opening closure device 31 can be designed with a flatter structure.

[0080] The example of the embodiment shown in Figure 10 illustrates that the camera device 38 can, in principle, also be arranged high up in the interior space 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 interchangeable and vice versa. Merely as an example, it is emphasized that the camera device 38 can also be positioned in the nested arrangement with the evaluation unit 57 in the embodiments shown in Figures 1 to 8 in order to displace the camera device 38 as high as possible; or that the opening closure device 31 can be designed as a rigid window or as a pivoting window; etc.

[0081] Figure 12 shows a processing machine 100 according to a further embodiment, which is designed as a mixer and has a plurality of inspection devices 30. The inspection devices 30 can be designed as shown in Figures 1 to 5 and 9 to 11, so that with regard to the similarities, reference is made to the above description. Identical or modified details are provided with the same reference numerals. To clarify the orientation of the processing machine 100 in space, Figure 12 shows a longitudinal direction X, a transverse direction Y, and a vertical direction Z, 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 with respect to the vertical direction Z.The processing machine 100 can be set up on a stationary floor which lies in a horizontal plane spanned by the longitudinal direction X and the transverse direction Y.

[0082] The processing machine 100 has several, here by way of example, ten, filling chutes 2 in a row one behind the other. The filling chutes 2 are connected to a channel 101 running above the filling chutes 2, which is connected on the input side via the inlet 4 to an upstream spinning preparation machine (not shown). The fiber material 3, usually provided in flake form, is pneumatically introduced into the filling chutes 2 via the inlet 4 and the channel 101. Control elements (not shown) can be provided in a conventional manner between the channel 101 and the individual filling chutes 2 in order to be able to control the filling of the individual filling chutes 2. In a conventional manner, a roller feed and an opening roller can be arranged in the lower part 8 of the respective filling chute 2, as shown in Figures 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 transported in the transport direction T via a pipeline system to a subsequent processing machine, for example the cleaner 1 shown in Figures 1 and 2.

[0083] In a front housing wall 34 of the processing machine 100, two inspection devices 30 are installed 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 the evaluation units 57 and, if necessary, at least one higher-level evaluation unit 60. The output values ​​can be summarized and averaged to obtain a more representative result. 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 measurement time.In addition, additional inspection devices 30 can also be arranged on a rear wall of the processing machine 100, such as on the front side shown in Figure 12. The more inspection devices 30 are provided, the shorter the measurement times can be achieved. For example, two inspection devices 30 can be provided for each filling shaft 2, one at the front and one at the rear, so that the mixer 100, shown here as an example with ten filling shafts 2, can have, for example, twenty inspection devices 30.

[0084] 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 handle the summarizing of the output values ​​and their transmission to a control unit. The control unit can be assigned to the downstream spinning preparation machine, in particular to the cleaner 1, which, based on the foreign matter content detected in the mixer 100, can automatically change the settings of the machine elements that influence waste separation, for example, by changing the position of the cleaning elements 15, 16.

[0085] Figure 13 shows yet another embodiment of the inspection device 30, which largely corresponds to the previously described inspection device 30, so that with regard to the similarities, reference is made to the above description. 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.

[0086] Reference symbol

[0087] 1 processing machine 41 deflection device

[0088] 2 filling shaft 42 beam path

[0089] 3 Fiber material 43 Beam path section

[0090] 4 Inlet 44 Beam path section

[0091] 5 upper part 45 upper section

[0092] 6 Dust extraction device 46 lower section

[0093] 7 Exhaust air duct 47 Surface

[0094] 8 lower part 48 detection width

[0095] 9 roller feed 49 clear width

[0096] 10 Feed roller 50 Lighting device

[0097] 11 Feed roller 51 Lighting element

[0098] 12 Feed roller 52 Lighting element

[0099] 13 Feed roller 53 Light source

[0100] 14 Opening roller 54 Camera

[0101] 15 Cleaning element 55 Lens

[0102] 16 Cleaning element 56 Data line

[0103] 17 Top circle 57 Evaluation unit

[0104] 18 Set 58 Housing wall

[0105] 19 Extraction hood 59 Viewing section

[0106] 20 Extraction hood 60 Evaluation unit

[0107] 21 waste strand 61 joint remedy

[0108] 22 Waste sensor device 62 Locking device

[0109] 23 Sensor 63 Direction

[0110] 24 Sensor 65 Start

[0111] 25 waste channel 70 steps

[0112] 26 Housing 71..76 partial step

[0113] 27 Housing opening 77 End

[0114] 28 Light barrier 80, 85, 90 step

[0115] 29 Pressure sensor 91 Start

[0116] 30 Inspection device 92 Optimization run

[0117] 31 Opening closure device 93..95 partial step

[0118] 32 separating element 96 end

[0119] 33 Cover element 100 processing machine

[0120] 34 Housing wall 101 Channel

[0121] 35 Outside

[0122] 36 Frame A Direction

[0123] 37 Interior E Observation Level

[0124] 38 Camera device F Fill level

[0125] 39 Observation area T Transport direction

[0126] 40 optical axis X, Y, Z longitudinal, transverse, vertical direction

Claims

Patent claims 1. A method for detecting foreign bodies in fiber material (3) accommodated in a filling chute (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 chute (2) can be viewed from the outside, and an inspection device (30) closing the housing opening (27), which comprises a separating element (32) with a transparent observation area (39) and at least one camera (54) looking through the observation area (39) into the filling chute (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 output 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 by means of a waste sensor device (22) by means of at least one optical sensor (23, 24) (80).

2. Method according to claim 1, characterized in that the method further comprises at least one of the following steps, in particular before carrying out the optimization run: 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 given and / or previous waste value.

3. Method according to claim 2, characterized in that the step of the optimization run (92) is carried out when the output value deviates from the predetermined and / or previous output value and when the current waste composition deviates from the predetermined and / or previous waste value. Method according to one of claims 1 to 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 interior space the at least one camera (54) is arranged. Method 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 in that a deflection device (41) is arranged in the interior space (37) of the opening closure device (31), which deflects a beam path (42) emanating from the observation area (39) towards the at least one camera (54). Method according to one of claims 1 to 4, characterized in that the at least one camera (54) is aligned towards the observation area (39).Method according to one of claims 1 to 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 (75) to a characteristic variable independent of the dynamic pressure. Method according to one of claims 1 to 7, characterized in that the inspection device (30) is retrofitted by inserting the inspection device (30) into an existing housing opening (27) of the processing machine (1; 100), through which the filling shaft (2) is visible from the outside. Method according to one of claims 1 to 8, 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 claims 1 to 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).

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