System for Analyzing and Selecting Material Parts

Abstract

The system analyzes and sorts material parts, particularly scrap parts made of aluminum. The laser device 140 generates a plasma 3 on the surface 7A of the material part 120. The detection unit 21 has objective lenses 25A, 25B, 25C, 25D paired with a detection cone 35 that forms a plasma detection area 39 within an area 37 overlapping the laser beam 5. The detection unit 21 has additional objective lenses 25A, 25B, 25C, 25D paired with an additional detection cone 35 that forms an additional plasma detection area 39 in an additional area 37 overlapping the laser beam 5. The objective lenses 25A, 25B, 25C, 25D are arranged and / or aligned in relation to each other such that the plasma detection area 39 and the additional plasma detection area 39 are offset along the beam axis 5A of the laser beam 5 and together form the field of view area 41 of the detection unit 21.

Description

Technical Field

[0001] The present invention relates to a system for analyzing and sorting material parts, in particular scrap parts made of aluminum.

Background Art

[0002] The system according to the present invention includes a supply means for transporting material parts (material components, material portions), a sorting unit configured to supply the material parts to one of two fractions (sub-portions, fractions), and a laser device configured to generate plasma on the surface of the material parts with a laser beam propagating along the beam axis. The system further includes a spectrometer system configured to perform spectral analysis of the plasma light emitted from the laser-induced plasma and generate an output signal according to the result of the performed spectral analysis, and a control device configured to receive the output signal and operate the sorting unit based on the output signal and sorting criteria (sorting criterion). Here, the spectrometer system includes a spectrometer and a detection unit (detection part) optically connected to the spectrometer. The detection unit includes an objective lens associated with a detection cone (detection cone) forming a plasma detection region in an overlapping region (overlap region) with the laser beam.

[0003] The above-mentioned, i.e., the general type of system, is known from Patent Document 1. The aforementioned system is based on laser-induced plasma spectroscopy, also known as LIBS (Laser-Induced Breakdown Spectroscopy), and enables the sorting of material parts, particularly scrap parts made of aluminum. Laser-induced breakdown spectroscopy LIBS is used to measure the element-specific composition of material parts, i.e., samples, using plasma. The plasma is generated on the surface of the material part by high-intensity focused laser radiation. The light mimicked by the plasma is spectrally analyzed by being detected to draw conclusions about the elemental composition of the material part.

[0004] According to the conventionally known system, the material parts to be sorted are supplied to the supply means. The supply means can be, for example, a plate that moves by vibration and provides a supply surface on which the material parts move. The material parts analyzed and sorted according to Patent Document 1 are supplied to the chute by the supply means. According to the force of gravity, the material pieces (material parts) slide down the chute and leave the chute through the lower end of the chute. From here, the material parts to be analyzed and sorted move freely in free fall through the surrounding atmosphere while following the force of gravity. In this case, the supply means and the chute play a role in ensuring that the material parts move in free fall through a spatially defined falling path by separating the material parts.

[0005] During free fall, laser-induced plasma spectroscopy is performed for each material emerging from the chute. For this purpose, a laser device is provided that is installed to generate plasma on the surface of the material part with a laser beam propagating along the beam axis. Furthermore, a spectrometer system is provided that performs spectral analysis of the plasma light emitted from the laser-induced plasma and generates an output signal according to the result of the spectral analysis.

[0006] This output signal, when combined with a sorting criterion, is used by a sorting unit to supply the material parts exiting the chute to one of two fractions. The sorting device (sorting device) can be, for example, an air nozzle appropriately controlled by a control device. In this way, under the influence of air pressure, it is possible to sort specific material parts from the flow of material parts exiting the chute. As a result, sorted material parts and unsorted material parts are produced.

[0007] Generally, conventionally known systems are used to recognize material parts of a specific composition and separate them from material parts of different compositions. Such separation is carried out either when material parts of an undesirable composition are recognized and discharged by the sorting unit, or when the composition of the material parts cannot be reliably determined and are discharged by the sorting unit. Therefore, the proportion of material parts to be discharged is composed of, on the one hand, material parts with a clearly specified composition and undesirable material parts, and on the other hand, material parts whose composition is not clearly identified.

[0008] The system described above has been proven in daily practical applications, but there is still room for improvement. In particular, although the drop path (drop corridor) is defined, the configuration of the material parts cannot be clearly identified, so it has been found that the material parts become unqualified. Also, material parts that should not have become unqualified if clearly identified may sometimes become unqualified. Such incorrect discharges are particularly due to the fact that, despite keeping to the drop corridor, the material parts fall beyond the plasma detection area of the lens of the detection unit due to their geometric shape. This is especially the case for spherical or partially spherical material parts.

[0009] Incorrect sorting leads to a detrimental decrease in sorting efficiency. This might be improved by narrowing the drop path. However, this is not only technically complex but also slows down the sorting speed. Furthermore, especially spherical or hemispherical material parts are guided to a safe position by both the supply means and the chute, but during free fall, there is a risk of assuming an orientation that no longer enables reliable detection of the material composition. Thus, it is not possible to guarantee that the material parts to be analyzed do not fall beyond the plasma detection area.

[0010] Another common system is known from Patent Document 2. This document also describes an embodiment using a perforated mirror. Specifically, a mirror arranged between a condenser lens (focus lens) and a laser is provided. This mirror has holes through which the laser beam generated by the laser is guided to the condenser lens. A detection cone is associated with the condenser lens. A plasma detection area is formed in the area overlapping with the laser beam. This known system has an additional condenser lens associated with a detection cone that interacts with the detector. In this case, the backlight emitted from the plasma is guided parallel by the first condenser lens, deflected by the mirror, and then focused in the beam direction and onto the detector by an additional condenser lens.

Prior Art Documents

Patent Documents

[0011]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0012] Therefore, based on the above-described prior art, it is an object of the present invention to further develop the design of a system of the above-described type so as to achieve an improvement in sorting efficiency.

Means for Solving the Problem

[0013] (1) To solve this problem, in the present invention, the detection unit has an additional objective lens (additional objective lens, additional detection cone) associated with an additional detection cone (additional detection cone). The additional detection cone forms an additional overlap region (additional overlap region, additional overlap region) and an additional plasma detection region (additional plasma detection region, additional plasma detection region) with the laser beam. The plasma detection region and the additional plasma detection region are arranged offset along the beam axis of the laser beam, and the objective lenses are proposed to be arranged and / or aligned in relation to each other (relative to each other, in relation to one another) so as to form the field of view region of the detection unit together.

[0014] The design according to the present invention advantageously provides an enlarged detection area. As a result, more material parts can be reliably recognized with respect to their composition. As a result, incorrect sorting is minimized, so the sorting result is improved. As a result, the sorting process becomes more effective.

[0015] The expansion of the detection range is due to the fact that, in contrast to the prior art, not only one lens but a plurality of lenses, that is, at least two lenses, are provided. However, it is preferable that two or more lenses, for example, three, four, or more lenses.

[0016] A plasma detection range is set for each lens. Therefore, in the case of four lenses, there are four plasma detection regions. According to the present invention, it is further provided that the plasma detection regions are offset along the beam axis of the laser beam, and the lenses are arranged and / or aligned in relation to each other so as to together form the field of view of the detection unit. The field of view represents the detection region as an overall result composed of individual plasma detection regions. Therefore, the field of view is significantly larger than that of the prior art.

[0017] According to the prior art, the detection region is formed by only one plasma detection region of the lens. Along the beam axis of the laser beam, such a plasma detection region can usually extend over a distance of 8 - 10 mm. The configuration of the field of view region of the detection unit according to the present invention, which has individual plasma detection regions arranged offset along the beam axis, results in an overall detection region having an extension of 20 mm, 30 mm, 40 mm, or more in the direction of the beam axis. In this way, advantageously, for geometric design, especially for spherical or partially spherical material parts, it becomes possible to reliably detect material parts that were previously undetectable.

[0018] As a result, in the system according to the present invention, the proportion of material parts that are rejected due to their composition being unable to be reliably identified is minimized. Thus, sorting can be improved.

[0019] (2) According to a further feature of the present invention, it is provided that the plasma detection region is set such that when plasma is present in the plasma detection region, the measurement component (measurement share, measurement part) of the plasma light is detected by the relevant lens. Therefore, when the laser-induced plasma is at least partially present in the plasma region, the measurement component of the emitted plasma light is detected by the relevant lens. In the case of a plurality of lenses according to the present invention, this means that the detection unit can detect the plasma light in the form of the measurement components of the individual lenses.

[0020] (3) According to a further feature of the present invention, it is provided that the detection unit has a lens holder that jointly supports a plurality of lenses. According to this further development, a compact design is achieved. The detection unit has only one lens holder. This lens holder supports all the lenses and enables the lenses to be arranged close to each other. This ensures an easy-to-handle and compact design.

[0021] (4) According to a further feature of the present invention, it is provided that the plasma detection regions are arranged to intersect each other or be spaced apart from each other along the beam axis. Alternatively or additionally, each of the plasma detection regions can extend along the beam axis over 1 / 10 to 1 / 4 of the field of view region. Thus, in particular after the sorting operation, the following is made possible. By appropriately arranging the plasma detection regions, a detection region is obtained as a result.

[0022] (5) According to a further feature of the present invention, it is provided that the lens holder provides an optical through-opening through which the beam axis passes. Accordingly, when the lens holder is used as intended, i.e., along the beam axis, it has an opening through which the laser beam is guided. This also further promotes the formation of a compact design.

[0023] (6) According to a further feature of the present invention, the lens holder (lens mount, lens retaining part) comprises a mounting plate (holder plate, mount plate). The mounting plate provides a plurality of objective lens mounting openings (objective mount opening, lens holder hole) for receiving the objective lenses respectively, and an optical passage opening for the laser beam. It is provided that the lens mounting openings are distributed (dispersed) around the optical passage opening.

[0024] According to this preferred embodiment, the lens holder has a mounting plate. This mounting plate is used to place individual lenses. One opening is provided for each objective lens. Through this opening, the lens is guided and attached to the mounting plate. The mounting plate is also provided with an opening for the laser beam to pass through. It is particularly preferred that the lens mounting openings are distributed (dispersed) around the laser beam passing opening. This design means also supports the design of a compact structure.

[0025] (7) According to a further feature of the present invention, it is provided that a detection cone extends along an observation axis that extends at an observation angle with respect to the beam axis. The observation angle is within 0° to 90°, preferably within 3° to 60°, more preferably within 5° to 25°. The purpose of setting the observation angle is to form an optimized plasma detection region for each lens, particularly with respect to its geometric position. Depending on the design of the desired field of view window, it is possible to select different observation angles for individual lenses. In some cases, it is possible to make some plasma detection regions closer to each other than other plasma detection regions. However, the observation angles of individual lenses are preferably approximately the same size. For example, the maximum deviation between the observation angles of the lenses from each other is less than 3°.

[0026] (8) According to a further feature of the present invention, it is provided that the spectrometer system has a light guiding (optical guiding) system that optically couples the detection unit to the spectrometer. In this way, the spectrometer system has a spectrometer, a detection unit, and a light guiding system. The light guiding system serves to optically couple the detection unit to the spectrometer. In this way, the plasma light captured by the detection unit is transmitted to the spectrometer by the light guiding system and spectral analysis is performed by the spectrometer.

[0027] (9) According to a further feature of the present invention, the light guiding system has a plurality of light inputs (optical inputs). Preferably, the light guiding system comprises a number of light inputs corresponding to the number of objective lenses. Each light input of the light guiding system is assigned to an objective lens.

[0028] The light guiding system also has a light output (optical output). The light output is used to output the measurement components captured by the lens. Thus, the measurement components recorded on the input side of each lens are jointly output to the spectrometer (spectroscopic device) via a single light output.

[0029] The advantage of this design is that the spectrometer receives all the plasma light measurement values of each material component recorded by the lens simultaneously. That is, all the measurement values can be processed simultaneously. This significantly reduces (alleviates) the required computer performance as opposed to analyzing individual measurement values separately.

[0030] (10) According to a further feature of the present invention, the light guiding system has a plurality of optical fibers. Each optical fiber provides a light input. It is provided that the plurality of optical fibers are combined to form a common light output. Accordingly, the optical fibers are coupled to the lens on each input side. On the output side of the optical fiber, the optical fiber is connected to the common light output. This light output is optically opened in the spectrometer as described above.

[0031] (11) According to a further feature of the present invention, the laser device, the spectrometer system, and the control device are housed in a common housing and are provided to form a laser-induced breakdown spectroscopy LIBS module.

[0032] Such a laser-induced breakdown spectroscopy LIBS module is easy to handle, especially for installation and maintenance. It also has a compact design, is robust due to the housing, and is protected from external mechanical influences.

[0033] (12) According to a further feature of the present invention, the supply means for conveying the material parts (material portions, raw material parts) is arranged (positioned, configured) to convey the material parts along the supply surface up to the upper edge portion (upper stage portion) of the chute. According to this preferred embodiment, the material parts are supplied to the supply means. From there, they reach the chute, where they are conveyed along the supply surface of the supply means up to the upper edge of the chute. When the material reaches the chute, it descends along the chute according to the force of gravity. The supply means can be designed, for example, as a rocking plate, whereby the material parts supplied to the supply means are separated. The purpose of the chute is in particular to align the material (raw material) parts and transfer them to a defined drop path.

[0034] However, according to an alternative embodiment, it is also possible to design the supply means as a circulating conveyor belt. In this case, the material parts to be analyzed and sorted are placed on the conveyor belt and moved by the conveyor belt.

[0035] (13) According to a further feature of the present invention, the sorting unit is assigned to the lower edge of the chute on the side opposite to (opposite) the upper edge of the chute. It is provided that the sorting unit is arranged to supply the material parts emerging from the chute via the lower edge of the chute to one of two fractions (sub-portions, fractions).

[0036] According to this preferred embodiment, the material parts leave the chute by free fall and are analyzed and sorted by free fall. For this purpose, in particular the laser device and the spectrometer system are arranged in the vertical direction below the lower edge of the chute.

[0037] Alternatively, the laser device and / or the spectrometer system can also be arranged above the shoot and / or supply means. For example, if the supply means is designed as a conveyor belt, the detection is preferably carried out from above, whereby the sorting can be carried out by air bombardment from the side with respect to the conveyor belt, or the material parts are intended to be observed from above. However, the sorting is carried out only after the material parts have fallen freely after leaving the conveyor belt on the discharge side. In this case, the sorting can be carried out from any direction.

[0038] Further features and advantages of the present invention are shown in the following description with reference to the figures. The figures show the following.

Brief Description of the Drawings

[0039]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5A

Figure 5B

Figure 6A

Figure 6B

Figure 7

Mode for Carrying Out the Invention

[0040] FIG. 1 is a schematic diagram of a system 100 according to the present invention. System 100 subjects material parts 120 to laser-induced plasma spectroscopy and is set to sort them according to the results of the spectral analysis. In the illustrated embodiment, two fractions F1 and F2 to which the material parts 120 can be assigned are provided. For example, collection points 170 in the form of containers are used to receive each of the fractions F1 and F2.

[0041] As also shown in the schematic diagram according to FIG. 1, system 100 includes supply means 110 following chute 130. In the intended use example, the material parts 120 are supplied to the supply means 110. The supply means 110 serves to convey the material parts 120 along a supply surface 111 provided by the supply means 110, that is, up to the upper edge 131 of the chute 130. Here, the material parts 120 are conveyed from the supply means 110 to the chute 130.

[0042] The supply means 110 can be designed as a plate that moves while vibrating. In particular, the supply means 110 serves to separate a plurality of material parts 120 supplied onto the supply means 110, thereby making it possible to supply these plurality of material parts 120 to the chute 130 with a greater spacing from each other.

[0043] The material parts 120 transferred to the chute 130 slide down the chute 130 under gravity until they reach the lower edge 132 of the chute formed on the side opposite to (facing) the upper edge 131 of the chute 130. In particular, it is the task of the chute 130 to align the material parts 120 and transfer them to a defined drop path.

[0044] When the shot 130 is fired, the material component 120 continues to move through the bypass atmosphere while freely falling under the influence of gravity. During this time, as will be described in detail below, it passes through the spectrometer system 1 according to the present invention for analyzing the material component 120. The spectrometer system 1 generates an output signal corresponding to the result of the performed spectral analysis. This output signal is supplied to the control device 150, and the control device 150 operates, i.e., controls, the sorting unit 160 as a function of this output signal on the one hand and as a sorting criterion on the other hand. By this sorting unit 160, the material component 120 is either deflected (biased) or not deflected during free fall. If no deflection occurs, the material component 120 reaches the collection point 170 of the second fraction F2. Otherwise, i.e., if sorting is performed by the sorting unit 160, the material component 120 reaches the collection point 170 of the first fraction F1.

[0045] The spectrometer system 1, which is part of the laser-induced breakdown spectroscopy LIBS module 180 according to the present invention, is used to analyze the composition of the material component 120. The laser-induced breakdown spectroscopy LIBS module 180 also includes a laser device 140 and a control device 150. Preferably, the laser device 140, the spectrometer system 1, and the control device 150 are housed in a common housing not shown in detail in FIG. 1.

[0046] The laser device 140 is configured to include individual components such as, for example, a laser beam source 9, an optical fiber 9A, a condensing optical system 11, as can be seen from the embodiment according to FIG. 2 in particular. As described below with particular reference to FIGS. 2 and 3, the spectrometer system 1 includes a detection unit 21. This detection unit 21 includes a plurality of lenses. A detection cone 35 is assigned to each of these lenses. Each detection cone 35 forms a plasma detection region 39 in a region (overlap region, overlapping region) that overlaps the laser beam 5. These plasma detection regions 39 are arranged offset from each other along the beam axis of the laser beam 5 and together form the field of view region 41 of the detection unit 21. Thus, the field of view region (field of view) 41 is configured with individual plasma detection regions 39 and defines the detection region covered by the detection unit 21 as a whole.

[0047] FIG. 2 shows an overview of the spectrometer system 1 for spectral analysis of the plasma light 3A already emitted by the laser-induced plasma 3 (shown schematically as a filled circle). The detectable plasma light 3A is present, for example, in the wavelength ranges of ultraviolet light, visible light, near-infrared light, and / or infrared light. In particular, the detected plasma light can be present in the spectral range of approximately 190 nm to approximately 920 nm. In laser-induced breakdown spectroscopy LIBS, the plasma 3 is generated on the surface 7A of the sample 7 by the laser beam 5.

[0048] The spectrometer system 1 is configured to include a laser beam source 9 for generating, for example, a pulsed laser beam 5. The laser beam source 9 is designed to provide the laser beam parameters necessary for plasma generation. The laser beam 5 is supplied to the focusing optical system 11 via, for example, an optical fiber 9A, and thereby focused on the surface 7A of the sample 7 (material component 120 according to FIG. 1). Since the focusing optical system 11 can be designed as a laser head component having a focusing function in particular, it can be designed, for example, as an active laser component having a focusing function that acts on, in particular, the spectrum, pulse duration, or pulse energy. The laser beam 5 propagates between the focusing optical system 11 and the sample 7 along the beam axis 5A. The exemplary focusing diameter (1 / e 2 beam diameter) and the focusing length (double Rayleigh length) are in the ranges of <50 pm (less than 50 pm) to >250 pm (more than 250 pm) and <5 mm (less than 5 mm) to >1000 mm (more than 1000 mm), respectively.

[0049] In particular, the region where plasma generation can occur (also called the ignition region) can be set / selected such that the laser parameters are, for example, along the beam axis 5A, and extend over a length in the range of about 5 mm to about 50 mm, for example, a length of 10 mm, 20 mm, or 30 mm.

[0050] FIG. 2 schematically shows a long focusing zone 11A along the beam axis 5A formed in the region of the surface 7A of the sample 7. The plasma 3 is formed on the surface 7A of the sample 7 by the interaction between the laser radiation and the material. In laser-induced breakdown spectroscopy LIBS, the normal dimension (average diameter) of the plasma 3 is, for example, in the range of 0.1 mm to 5 mm (depending on the sample material and laser parameters).

[0051] The spectrometer system (spectral system, spectrometer system) 1 also includes a spectrometer (spectroscope, optical spectrometer, light spectrometer, optical spectrophotometer) 13 for spectroscopically analyzing the plasma light 3A. In FIG. 2, the spectrometer 13 is shown, for example, as a grating spectrometer. Generally, the spectrometer 13 includes at least one dispersive element 13A, such as a diffraction grating, a prism, or a diffraction grating prism, and a pixel-based detector 13B onto which the plasma light is incident in a spectrally expanded manner. The spectral components of the plasma light 3A to be analyzed are assigned to the pixels of the detector 13B. The detector 13B outputs the intensity values of the irradiated pixels to an evaluation unit 15, which is usually a computer having a processor and a memory. The evaluation unit 15 outputs the measured spectral distribution 17. The evaluation unit 15 compares, for example, with the stored comparison spectrum to assign the elements contributing to the plasma light 3A, and thus to the sample (7) to be analyzed, and outputs the result as a spectral analysis result.

[0052] In the spectrometer 13, the (spectrum-dependent) beam entrance of the plasma light to be analyzed is defined by an entrance aperture 19, usually by an entrance slit 19A.

[0053] The spectrometer system 1 further includes a detection unit 21 having an objective lens holder 23 and a plurality of objective lenses 25A, 25B, 25C held by the objective lens holder 23. As an example, three lenses are shown in the figure, two in the image plane and one behind it. The number of lenses used can be selected according to spatial and optical parameters and the parameters of the material of the sample to be analyzed, for example, in the range of 2 to 20, such as 4, 5, 8, 9, or 15 lenses.

[0054] The spectrometer system 1 further includes, in particular, the detection unit 21 further includes a light guiding system (optical guiding system) 27 that optically connects the objective lenses 25A, 25B, and 25C to the spectrometer 13. The light guiding system 27 provides a plurality of light inputs (optical inputs, light input parts) 29, each of which is optically assigned to one of the objective lenses 25A, 25B, and 25C, and one light output (optical output, light output part) 31 that is optically assigned to the entrance aperture 19 (common to the objective lenses).

[0055] Each of the lenses 25A, 25B, and 25C is composed of at least one condensing optical element such as a converging lens or a concave mirror by being set to detect the measurement component 33 of the plasma light 3A. A detection cone 35 is assigned to each of the lenses 25A, 25B, and 25C. Since the beam axis 5A passes through the detection cone 35, the detection cone 35 has a minimum size set in the region of the laser beam 5. Each detection cone 35 constitutes a plasma detection region 39 in the region (overlap region) that overlaps the laser beam 5 assigned to the corresponding lens 25A, 25B, and 25C. For example, the detection cone 35 has a length existing in the range of 200 mm to 400 mm from the entrance aperture of the objective lenses 25A, 25B, and 25C to the laser light. In FIG. 2, for example, the plasma 3 is generated by the plasma detection region 39 of the lens 25B. The related measurement component (measurement share) 33 of the plasma light 3A is detected by the lens 25B and is imaged on the related light input 29 of the light guiding system 27. The measurement component 33 detected by one or more lenses is guided (guided) to the common light output 31 by the light guiding system (optical guiding system) 27 and is coupled to the spectrometer 13 through the entrance aperture 19 for spectral analysis.

[0056] FIG. 2 shows an example in which three lenses 25A, 25B, and 25C are arranged with an azimuthal (azimuth) distribution around the beam axis 5A. Since the lenses 25A and 25B are located on opposite sides of the beam axis 5A, they are thus directed toward the beam axis 5A from opposite sides. The lens 25C is directed toward the beam axis 5A from the rear. Further lenses (not shown in FIG. 2) are, for example, directed toward the beam axis 5A from the front or, using a beam splitter, directed toward the focusing zone (focus region) 11A along the beam axis 5A. To clarify this, in FIG. 2, a detection cone 35 is shown by a dashed line extending conically toward the beam axis 5A. Thus, the focusing zone 11A, the plasma 3, and the plasma detection region 39 are shown oversized compared to the detection cone 35 to clarify them.

[0057] FIG. 3 shows a mounting plate (holder plate, mount plate) 23A of a detection unit 21 of a laser-induced breakdown spectroscopy LIBS system to explain the arrangement (alignment) and alignment of the lenses 25A, 25B, and 25C. To fixedly mount the lenses, the mounting plate 23A has lens mounting openings for receiving the lenses 25A, 25B, and 25C. By arranging the lens mounting openings at a radial distance from the beam axis 5A, the lenses 25A, 25B, and 25C are designed to be arranged obliquely with respect to the beam axis 5A. The observation axes 35A of the lenses 25A, 25B, and 25C are shown to explain the oblique alignment. In the example shown, the observation axis 35A extends at an observation angle a with respect to the beam axis 5A.

[0058] In order to implement the multi - focal concept, the lenses 25A, 25B, 25C are fixed to the mounting plate 23A (generally aligned by being disposed in the lens holder (lens mounting portion) 23) such that the plasma detection regions 39 are offset from each other along the beam axis 5A. In particular, in the case of observation angles α that are equal to each other, the offset in the direction of the beam axis 5A can be achieved by changing the radial distances of the lenses 25A, 25B, 25C from the beam axis 5A (optionally changing the insertion amount). As an example, the different radial distances R1, R2 between the lenses 25A, 25B are shown in FIG. 3. Alternatively (optionally, the same radial interval can also be taken), at least a part of the observation angle α of the lens can also be adapted to the desired offset of the plasma detection region 39 in the direction of the beam axis 5A (see, for example, FIG. 6B). A mixed form of the configuration is also possible.

[0059] Generally, the observation angle a can be in the range from 0° (along the laser beam through the beam splitter) to 90° (observation orthogonal to the laser beam). The observation angle a shown as an example in the context of the present disclosure is in the range from 5° to 15°, for example, in the range from 5° to 10°. The observation axes 35A of the lenses 25A, 25B, 25C adjacent to each other approach the beam axis 5A from different azimuth directions (azimuth within a plane perpendicular to the beam axis 5A). In the case shown in FIG. 3, the observation angle a is the same for all the lenses 25A, 25B, 25C and does not deviate from each other by more than, for example, 5° or 1° (for example, deviation due to the lens mounting opening or the allowable manufacturing tolerance of the lens). However, the radial distances from the beam axis 5A are different in the arrangement shown in FIG. 3. Therefore, for samples existing at different positions on the sample surface along the beam axis 5A (corresponding to different measurement constellations in the context of the measurement process), for example, for the surface profile along the solid line (the surface 7A of the sample 7 from FIG. 2), from the objective lens 25B; for the surface profile along the dotted line 7A′, from the objective lens 25A; for the surface profile along the dashed line 7A″, from the objective lens 25C, it is possible to record equivalent spectra from the plasma detection regions 39 of different objective lenses to each other.

[0060] As shown in FIG. 3, the plasma detection regions 39 together form the field-of-view region 41 of the detection unit 21. The field-of-view region 41 extends along the beam axis 5A in the region of the focusing zone 11A.

[0061] The measurement depth along the beam axis 5A is assigned to each of the plasma detection regions 39. In FIG. 3, the measurement depth corresponds to, for example, the diameter of the circle indicating the plasma detection region 39. In the case of a lens, the measurement depth is a specific characteristic given by optical parameters such as the focal length and numerical aperture of the lens, as well as the arrangement and orientation of the lens (e.g., the geometric position parameters of the lens with respect to the beam axis 5A - distance and angle). For example, each of the plasma detection regions 39 can extend along the beam axis 5A over a measurement depth of about 5 mm to about 15 mm, particularly over a measurement depth of about 5 mm to about 12 mm. In some embodiments, the plasma detection regions 39 can extend along the beam axis 5A over 1 / 10 to 1 / 4 of the field (visibility) region 41. In FIG. 3, the plasma detection regions 39 arranged offset from each other along the beam axis 5A in a multi - focus concept are, as an example, spaced apart by a distance D of the order of the magnitude of the measurement depth (here about twice the diameter of the plasma detection region 39). Alternatively, the plasma detection regions 39 can be made to be adjacent to each other, partially overlapping (e.g., within a range of 10% of the measurement depth). In this way, the lenses can be made capable of detecting plasma light from different sections of the field region 41 along the beam axis 5A.

[0062] Further, FIG. 3 shows an optional protective window 43A. This protective window 43A can be provided in the region of the optical through - opening 43 in the mounting plate 23A. The protective window 43A can direct the laser beam that passes through the mounting plate 23A and through the lenses 25A, 25B, 25C towards the sample 7.

[0063] FIG. 4 is a perspective view of an exemplary laser-induced breakdown spectroscopy LIBS measurement head 51 connected to a laser beam source via an optical fiber 9A. The lens holder 23 of the laser-induced breakdown spectroscopy LIBS measurement head 51 includes a longitudinal support plate 23B. On this longitudinal support plate 23B, an attachment portion of the optical fiber 9A and the condensing optical system 11 (laser head with beam shaping function) is provided on the input side. The spectrometer 13 is also attached to the longitudinal support plate 23B. Four lenses 25A, 25B, 25C, 25D (generally an input optical system (entrance optics) with a magnification of n (>1)) are provided on the longitudinal attachment plate 23A. The lenses 25A, 25B, 25C, 25D detect plasma light measurement components (measurement components, measurement shares) from the plasma detection regions 39 that are offset from each other along the beam axis 5A. The lenses 25A, 25B, 25C, 25D are set to supply the plasma light measurement components to the spectrometer 13 for spectral analysis via a light guiding system 27 (for example, a fiber bundle - "n-on-1 fiber bundle" having an input of n>1 and a functional output). As an example, two optical fibers 45 of the light guiding system 27 are shown in FIG. 4. The two optical fibers 45 optically connect the lenses 25B and 25C to a common spectrometer 13. The light guiding system 27 can be used to couple the measurement components (measurement shares) to each other within the spectrometer 13 (or optionally before coupling to the spectrometer 13) for measurement processing.

[0064] By observing the field of view n times with a plurality (four in FIG. 4) of lenses, the depth of field can be significantly increased by juxtaposing the plasma detection regions of the lenses. As a result, even a sample with structured unevenness on the surface can be efficiently analyzed. Furthermore, by observing the sample from various angles, the shadowing effect can be reduced. The recorded measurement components are combined at the common output (total of all observations) of the light guiding system and supplied to a common spectral analysis.

[0065] The "n on one" (n-on-1, n-to-1) fiber bundle enables a plurality of objective lenses to be supplied to a single spectrometer. Thus, it is possible to use a plurality of n-on-1 bundles to supply a plurality of spectrometers.

[0066] An exemplary embodiment in the detection unit 21 shown in FIG. 3 will be further described with reference to FIGS. 5A and 5B. FIG. 5A is a top view of the mounting plate 23A. The central optical through-opening 43 allows a laser beam to pass through (laser beam axis 5A). Four lens mounting openings (lens mounting holes, lens holder openings) 53A, 53B, 53C, 53D are arranged in the azimuth (azimuth) direction around the optical through-opening 43 while varying the radial distance with respect to the beam axis 5A. These four lens mounting openings 53A, 53B, 53C, 53D are evenly arranged in the azimuth direction such that two lens mounting openings form a pair and face each other. In the perspective view of FIG. 5B, four identical lenses 25A, 25B, 25C, 25D are inserted into the lens mounting openings 53A, 53B, 53C, 53D. The lenses 25A, 25B, 25C, 25D are inserted into the lens mounting openings 53A, 53B, 53C, 53D at different distances from each other. Thus, depending on the radial distance, the associated plasma detection regions 39 are arranged adjacent to each other in the beam axis direction. Thus, the depth of field field region 41 of the detection unit 21 is formed.

[0067] Alternative embodiments are shown in FIGS. 6A and 6B. In the top view of the mounting plate 23A, four lens mounting openings 55A, 55B, 55C, 55D can be recognized. These lens mounting openings 55A, 55B, 55C, 55D are symmetrically arranged at the same radial distance from the optical through-opening 43 and are evenly distributed around the optical through-opening 43 in an exemplary manner. As shown in the perspective view of FIG. 6B, the offset between the plasma detection regions 39 in the direction of the beam axis 5A is caused by the different viewing angles of the lenses 25A, 25B, 25C, 25D used. For example, at a radial distance of 30 mm, the viewing angle can range from 3° to 15°. Thereby, the field of view region 41 is formed at a distance of about 100 mm from the mounting plate 23A. Due to the different field of view angles (and optionally the field of view height), the detected spectral distribution can vary for a large volume (large volume) plasma. However, especially in the case of a small volume plasma such as that typically generated for laser-induced breakdown spectroscopy LIBS, since essentially the entire plasma is present within the plasma detection region 39, these differences in the spectral distribution can be ignored.

[0068] FIG. 7 shows again a detailed view of the system 100 according to the invention shown in FIG. 1. Here, it can be seen that different material components are provided in its configuration, namely a plastic material component 120B and a first material component 120A made of aluminum. In the above-described manner, the spectrometer system 1 according to the invention can be used to sort the first material component 120A from the second material component 120B. For this purpose, if the plastic second material component 120B is recognized, it is discharged by the sorting unit 160. For this purpose, the sorting unit 160 has a pneumatic nozzle that can discharge the plastic component (120B) from the flow of material components. As a result of such sorting, on the one hand, the plastic second material component 120B and on the other hand the aluminum first material component 120A are separately accumulated at the collection (integration) point 170.

Description of the reference numerals

[0069] 1…Spectrometer system 3…Plasma 3A…Plasma light 5…Laser beam 5A…Beam axis 7…Sample 7A…Surface 7A′…Dashed-dotted line 7A′′…Dashed line 9…Laser light source 9A…Optical fiber II…Focusing optical system 11A…Focusing zone 13…Optical spectrometer 13A…Dispersion element 13B…Detector 15…Evaluation unit 17…Spectral distribution 19…Entrance aperture (entrance diaphragm) 19A…Entrance gap 21…Detection unit 23…Lens holder (lens mounting part) 23A…Mounting plate 23B…Longitudinal support plate 25A…Lens 25B…Lens 25C…Lens 25D…Lens 27…Light guiding system 29…Light input 31…Light output 33…Measured component 35…Detection cone 35A…Observation axis 37…Overlap region 39…Plasma detection region 41…Field of view region 43…Optical through aperture (optical through hole) 43A…Protective window 45…Optical fiber 51…LIBS measurement head 53A…Lens mounting aperture 53B…Lens mounting aperture 53C…Lens mounting aperture 53D…Lens mounting aperture 55A... Lens mounting opening 55B... Lens mounting opening 55C... Lens mounting opening 55D... Lens mounting opening 57A... Lens mounting opening 57B... Lens mounting opening 57C... Lens mounting opening 57D... Lens mounting opening D... Distance R1, R2... Radial distance a... Observation angle 100... System 110... Supply means 111... Supply area (supply surface) 120... Material part 120A... Aluminum part 120B... Plastic part 130... Shoot (slide) 131... Upper end (upper end part) 132... Lower end (bottom edge part) 140... Laser device 150... Control device 160... Sorting unit (sorting part) 170... Collection point 180... LIBS module

Claims

1. A system for analyzing and sorting material parts, particularly scrap parts made of aluminum, the system comprising: feeding means (110) for conveying the material parts (120); a sorting unit (160) configured to supply the material parts (120) to one of two fractions (F1, F2); a laser device (140) configured to generate a plasma (3) on the surface (7A) of the material parts (120) by means of a laser beam (5) propagating along a beam axis (5A); a spectrometer system (1) configured to perform a spectral analysis of plasma light (3A) emitted from the laser-induced plasma (3) and to generate an output signal according to the result of the performed spectral analysis; a control device (150) configured to receive the output signal and to actuate the sorting unit (160) based on the output signal and a sorting criterion; wherein the spectrometer system (1) comprises a spectrometer (13) and a detection unit (21) optically connected to the spectrometer (13); the detection unit (21) has objective lenses (25A, 25B, 25C, 25D) to which a detection cone (35) is assigned, the detection cone (35) forming a plasma detection region (39) in an overlap region (37) with the laser beam (5); the detection unit (21) has further objective lenses (25A, 25B, 25C, 25D) to which a further detection cone (35) is assigned, the further detection cone (35) forming a further plasma detection region (39) in a further overlap region (37) with the laser beam (5); the plasma detection region (39) and the further plasma detection region (39) are offset along the beam axis (5A) of the laser beam (5), and the objective lenses (25A, 25B, 25C, 25D) are arranged and / or aligned in relation to each other such that the plasma detection region (39) and the further plasma detection region (39) together form the field of view region (41) of the detection unit (21); system.

2. When plasma (3) exists within the plasma detection region (39), the plasma detection region (39) is set such that the measurement component (33) of the plasma light (3A) is detected by the associated objective lenses (25A, 25B, 25C, 25D). The system according to claim 1.

3. The detection unit (21) includes a lens holder (23) that jointly supports a plurality of the objective lenses (25A, 25B, 25C, 25D). The system according to claim 1 or 2.

4. The plasma detection regions (39) are arranged to intersect or be spaced apart from each other along the beam axis (5A). The system according to any one of claims 1 to 3.

5. The lens holder (23) provides an optical through-opening (43) through which the beam axis (5A) passes. The system according to claim 3 or 4.

6. The lens holder (23) includes a holder plate (23A) that provides a plurality of lens mounting openings for receiving the optical through-openings (43) for the objective lenses (25A, 25B, 25C, 25D) and the laser beam (5) respectively, The lens mounting openings are distributed around the optical through-opening (43). The system according to any one of claims 3 to 5.

7. The detection cone (35) extends along an observation axis (35A) that extends at an observation angle a with respect to the beam axis, The observation angle a is within 0° to 90°, preferably within 3° to 60°, more preferably within 5° to 25°. The system according to any one of claims 1 to 6.

8. The spectrometer system (1) has a light guiding system (27) that optically connects the detection unit (21) to the spectrometer (13). The system according to any one of claims 1 to 7.

9. The light guiding system (27) provides a number of light inputs (29) corresponding to the number of the objective lenses (25A, 25B, 25C, 25D) and a light output (31), Each of the light inputs (29) is designed to receive the measurement component (33) detected by the associated objective lens (25A, 25B, 25C, 25D), The light output (31) is designed to output the measurement component (33) detected by the objective lenses (25A, 25B, 25C, 25D). The system according to claim 8.

10. The light guide system (27) has a plurality of optical fibers (45), and each of the plurality of optical fibers (45) provides the light input (29) and is combined to form the common light output (31). The system according to claim 9.

11. The laser device (160), the spectrometer system (1), and the control device (150) are housed in a common housing and form a LIBS module. The system according to any one of claims 1 to 10.

12. The supply means (110) is arranged to convey the material component (120) along the supply surface (111) towards the upper edge (131) of the chute (130). The system according to any one of claims 1 to 11.

13. The sorting unit (160) is assigned to the lower edge (132) of the chute (130) opposite to the upper edge (131) of the chute (130). The sorting unit (160) is set to supply the material component (120) exiting the chute (130) through the lower edge (132) of the chute (130) to one of two fractions (F1, F2). The system according to claim 12.

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