DE102006018287B4 - Apparatus and method for the spectral analytical evaluation of materials or objects in a material or object stream - Google Patents

Abstract

Device for spectrally-analytical evaluation of materials or objects (12, 16) in a stream of materials or objects, comprising a plurality of light sources (1) and a plurality of optics with which transmitted, reflected or reflected light (9) transmitted by the materials or objects is transmitted to a spectrograph being, being
at defined distances and transversely to the material or object stream (12, 16) light sources (1) are lined up in a row, characterized
in that light receiving optics (3, 4) are arranged in alternation with the light sources (1) in such a way that
in that the optical axes of the light-receiving optics (3, 4) lie in the plane of symmetry of the light irradiation (8) and the light sources (1) are arranged in a first focus of an elliptical cylinder mirror (2).

Description

The The invention relates to a device and a method for spectral analytical Evaluation of materials or objects in a material or Object current, with multiple light sources and multiple optics, with which remits transmitted by the materials or objects or reflected light is transmitted to a spectrograph. Here and below is under the of the materials or Objects transmitted light understood the light that passes through the Materials or objects is transmitted due to transmission.

spectrometer for the evaluation of raw materials and products are up to date known to the art. A good overview of this procedure gives that Book "IR Spectroscopy" by H. Günzler and H. M. Heise, published in 1996 in the VCH Verlagsgesellschaft mbH is. When measuring the spectral properties of samples is Note that the spectrometers themselves are not spectrally neutral are. Essential components of the spectrometers are the light sources, the optics and the sensors, each with its own spectral Show behavior. If one measures the spectral with a spectrometer Properties of a sample, one always has the influence of the spectrometer to take into account. As a rule, this is done by measurement against a known reference sample.

Under the chapter "Spectral decomposition" are mentioned in the Book on pages 58 to 61 such arrangements described wherein the reference sample is measured in a comparison beam path becomes. The comparison beam path must have the same optical properties like the measuring beam path own and the light must have optical Switch alternately directed to the sample and to the reference sample become. This is technically very complicated and for use in the evaluation unsuitable for raw materials and products in the production process.

To The state of the art is also the arrangement of the sample in the beam path always in a defined position. The measurement the sample from some distance or in rapid motion completely impossible. That is however for many tasks of quality control essential in the process.

to Measuring the remission or reflection of samples is the spectral Distribution of intensity of the incident light with the spectral distribution of the intensity of the remitted Light compared. It is based on the prior art on with a known remission diffuse scattering, spectrally neutral Medium reference. For the Remission at the sample is assumed to be a cosine distribution.

The Calibration of the spectrometer is done with calibration standards whose remission and measured at the location of the sample. The calibration The measuring system is carried out by processing a calibration routine. Since both the light sources and the sensors on the Time does not remain constant in its function, the calibration must the system as possible promptly for sample measurement, which is due to the complex handling laborious is.

Up to now, suitable calibration methods for use in the production process are only in the patent specification DE 102 33 375 described. The measuring light is directed to the sample through a measuring window that scatters the light. The light scattered back into the beam path is used to calibrate the measuring system if there is no sample. The measuring light remitted by the sample and the light directly scattered at the measuring window are coupled out laterally via deflecting mirrors from the symmetry axis or plane of symmetry of the irradiation. Lenses or lens combinations collect the light for detection in a spectrograph.

These Arrangement shows good results for DUTs immediately behind the scattering measurement window. At a greater distance the measuring system becomes very faint and a safe analytical evaluation of the samples becomes impossible. The lateral decoupling of the measuring light becomes especially with measuring head lines with a high number of measuring tracks due to the lateral arrangement very complex from many measuring optics and has not yet prevailed because of the high cost. Also lacks a suitable solution the measurement of products on moving belts from above, wherein a Measurement by a scattering measuring window due to the low luminous intensity of the measuring system not possible is.

Furthermore, from the patent DE 695 08 594 a method and apparatus is known in which material is tested for different composition. In this case, measuring light is directed to a broad material flow and the light remitted by the material is received over the entire width of the current by a receiving device and used to evaluate the material. In the 1 This patent is assigned to a number of detection points, consisting of lenses and optical fibers, light sources. The light sources radiate directly onto the materials, with the focal length of the light sources not being considered particularly critical.

The light at the detection points is fed to a receiving device and, finally, the material composition is determined in a data calculating device. Poor at this Measurement is that the spectra due to the poor optical properties of the described arrangement and the lack of a suitable calibration have systematic errors and even a rough identification of the materials is difficult. In the cited patent document, therefore, in order to improve the measurement results in the data calculation device, the data from the individual detection points are used to form a two-dimensional simulation of the material moving through the detection station, thereby improving the reliability of the material determination. Even with this additional effort, the results in material determination remain limited to a pure identification of the materials. A determination of the material composition and possible additives up to the trace range can not be done.

The publication DE 198 57 896 C1 discloses a method and apparatus for evaluating spectroscopic measurements on solid materials with spatially and / or temporally varying surfaces, such as woodchips, on a conveyor belt. According to one embodiment, a plurality of light sources and sensors are present in the transverse direction to the conveyor belt, wherein the wood chips are irradiated with the light sources and the emitted radiation is detected after interaction with the wood chips by the sensors. Thereafter, the radiation reflected from the material is fed to a spectrometer for the output of continuous Absorbtionsspektren. In another embodiment, a paper web is illuminated by a plurality of radiation sources with parallel light radiation. To detect the interaction signals, an arrangement of individual light-sensitive detectors is provided behind the radiation sources, with which an intensity or absorption spectrum is recorded.

The publication DE 31 00 304 A1 comprises a printing inspection apparatus in which the entire printing surface is scanned by a plurality of light emitting units and receiving units, wherein the units are arranged in a straight line so as to obtain image data from the printing. The image data thus obtained are compared with standard data to determine the quality of the print. The light emitted from the print is supplied to a photoelectric converter consisting of a pair of light receiving elements for generating an electrical signal in response to the amount of light of the emitted light.

The Document WO 93/10436 includes a device for detection of quality changes of bulk goods on running conveyor belts. The Device uses only one laser as light source and frequency multiplier, by several simultaneous light beams of different wavelengths produce and irradiate the bulk with it. According to the Number of irradiated areas are several detector systems with optical components for patterning the areas provided. By which the received signals are subsequently analyzed is in the Document not executed.

It The object of the present invention is a method for spectral analytical To provide measurement and a spectrometer with which a reliable one Spectral analysis of materials or objects in a stream of objects be realized with a compact design and little effort can.

The The object is achieved by a device of the type mentioned above, wherein at defined intervals and transverse to the object current light sources lined up in a row are, and alternately to the light sources Lichtaufnahmeoptiken such are arranged such that the optical axes of the light-receiving optics lie in the plane of symmetry of the light irradiation and wherein the Light sources in a first focus of an elliptical cylinder mirror are arranged.

With the inventive arrangement the space between the light sources can effectively through the Photographic optics are used. As a result of saving space creates a simple, compact construction of a spectrometer. furthermore can through the alternating arrangement of light-receiving optics and light sources, through which the light-receiving optics with respect to the optical axes can be placed between or next to the light sources, low optical Ways for that transmitted or remitted from the materials or objects reflected light can be achieved. Compared to conventional, As described above, the light-receiving optics can be used the device according to the invention thus arranged close to the materials or objects to be evaluated become, whereby the received light with same irradiation the materials or objects have a stronger intensity than at the devices in the prior art, in which the Light by deflecting mirror laterally out of the device on a Light receiving optics is passed. As a result, the intensity of the light, that is directed from the light sources to the materials or objects will be reduced, reducing the temperature load on the device as well as the materials or objects can be reduced.

By the arrangement of the light sources in a first focus of an elliptical Cylinder mirror can realize a high depth of focus of the measuring arrangement become.

In a particularly favorable Example of the invention runs the material or object stream through a second one-dimensional Focus of the cylindrical mirror and the optical axes of the light-receiving optics are perpendicular through the second one-dimensional focus. Accordingly the focus can be precisely aligned to the object stream, thereby a particularly reliable rating the materials or objects, at least in qualitative terms, is achievable.

Preferably The light-receiving optics include optical cables. optical cable have the advantage that they are placed flexibly between the light sources can be. It is also possible When using fiber optic cables, the distances between the light receiving optics flexible. Accordingly, the device depending on flexibly from the respective application with little effort or converted become.

It has also proven to be advantageous if the inlet openings the light guide cable directly or with at least one arranged in front of it Lens or lens combination on the second one-dimensional focus are directed. Thus, you can either by the optical cable itself or by means of the Lens or lens combination provided light-collecting effect those remitted or reflected from the materials or objects Light beams are accurately detected by direct optical path.

Corresponding a possible Variant of the invention are the light sources and the cylinder mirror below one provided in a transport device for the object stream Measuring window arranged such that light through the measuring window extends and the second focus of the cylinder mirror is in the measurement window. This arrangement has the advantage that a defined distance the light sources and the light-receiving optics of the device according to the invention exists for the materials or objects to be evaluated. To this Way not only can a very accurate qualitative evaluation but also a precise one quantitative assessment of the materials or objects to be measured respectively. For example, could hereby in the material or object stream located materials be determined from paper, which shares of lignin and minerals contained in the paper.

Instead of the use of one measurement window can be in another, as well suitable embodiment Invention Measurements and Evaluations of Materials or Objects in free fall by a lateral measurement.

According to one embodiment In the invention, the measurement window is in a chute for the materials or objects provided. This construction is exactly one defined distance between the light sources and light receiving optics of Device and the materials or objects adjustable.

there it is advantageous if the measurement window light scattering properties Has. Thus, light scattered by the measurement window can be ignored if none Materials or objects over the measurement window run or lie on it, to calibrate the Measuring device can be used.

Corresponding In another variant of the invention, the light sources are above one Transport device for the material or object stream or over a discharge curve of the transport device arranged, wherein the transport device is arranged or the trajectory is so, the overhead surfaces or portions of the materials or objects in the middle in the second one-dimensional focus of the cylinder mirror lie. This form of Arrangement allows one possible accurate measurement of objects or materials from above and enough usually for qualitative evaluation of objects or materials or for their identification.

According to one advantageous embodiment The invention relates to the light-receiving optics over the transport device for the Material or object stream or over arranged the discharge curve of the transport device, whereby a Measurement of objects or materials in reflection is possible.

It is however according to a further embodiment of the invention also possible, the light sources above of the material or object stream and the light receiving optics below one in the transport device, such as a conveyor belt for the Material or object stream downstream chute, provided Measuring window, whereby a measurement of the materials or Objects in transmission possible is.

The The object of the invention is further achieved by a method of the above Sort of solved, in which light from at defined distances and across the material or object stream lined up light sources on the material or Object current is blasted, and alternately to the light sources arranged light-receiving optics of the material or object stream record transmitted, remitted or reflected light, wherein the optical axes of the light receiving optics in the plane of symmetry of Light irradiation lie and wherein the radiated from the light sources Light with an elliptical cylindrical mirror on the material or Object stream or the transport device is directed.

With this method, it is possible that of the materials or objects transmitted, remitted or reflected light directly to receive on a short optical path. Since the light-receiving optics are close to the samples to be measured, the intensity of the light received is stronger than in prior art devices. In addition, the method according to the invention results in that a spectrometer using the method can be made simple and compact.

in this connection it is particularly advantageous that the radiated from the light sources Light time an elliptical cylindrical mirror on the material or Object stream or the transport device is directed. The of the light sources emitted light rays are in a second Focus of the cylinder mirror, through which the materials or objects are moved. In this way it is possible the Measure materials or objects with high light efficiency and at least qualitatively precise to rate.

According to one Great Variant of the invention is transmitted from the materials or objects, remitted or reflected light from fiber optic cables directly or with at least one lens or lens combination arranged in front of it taken and directed to the spectrograph. The fiber optic cables enable a spatial Separation of the measuring arrangement with the light sources and recording optics from the spectrograph to the transmitter. That's for use In the production process a significant advantage, since you are the special Conditions of the respective process better.

It is particularly beneficial when the light from the light sources so on the transport device or a discharge curve of the transport device is emitted, that overhead surfaces or areas of materials or objects lie in the middle in the focal plane of the cylinder mirror. With the help of this process variant, the materials or objects from the top, at least qualitatively accurately.

According to one Another variant of the invention, the light of the light sources through a provided in the transport device for the material or object stream Measuring window directed. With the help of this method can be a more accurate Distance between the spectrometer and the objects to be measured or materials are adjusted, which in addition to the quantitative also a very accurate qualitative spectral analytical evaluation the materials or objects can be done.

Corresponding a further variant of the method according to the invention is at least a remission normal arranged in the second focus of the cylinder mirror, are the spectral transmission, remission or reflection values of Materials or objects with the measured values of the remission standard normalized and become the normalized spectral measurements of individual measuring channels for the spectral-analytical evaluation of those recorded in the measuring channels Materials or objects used. For example, if no materials or objects are carried on the transport equipment, a remission normal or a plurality of remission normals in the beam path of individual measuring channels swung in or on a other suitable manner be introduced, so that the associated spectrometer can be calibrated.

According to one other possible Variant of the invention is the light scattered at the measuring window will, over the light guide led to the spectrograph, there detected and missing Materials or objects on the measurement window for normalizing the measured spectral transmission, remission or reflection of the Materials or objects used as reflectance standard in individual measurement channels. This embodiment offers Then, if a spectrometer below a measurement window in the transport device or a slide arranged thereafter is provided and there are no objects on the measuring window, the light scattered on the measuring window is very good for calibration of the spectrometer is suitable.

following Be exemplary embodiments explained by drawings. Show it:

1 a schematic representation of an inventive embodiment of the spectrometer with a row of lamps, a line of measuring optics in the measurement of products on a conveyor belt in a section from top to bottom through the direction of movement of a material flow;

2 a schematic representation of an inventive embodiment of the spectrometer as under 1 in a section from top to bottom perpendicular to the direction of movement of the material flow;

3 a schematic representation of an inventive embodiment of the spectrometer with a row of lamps, a line of measuring optics in the measurement of products on a slide in a section from top to bottom through the direction of movement of the material flow;

4 a schematic representation of an inventive embodiment of the spectrometer as under 3 in a section from the top to perpendicular to the direction of movement of the material stream;

5 a schematic representation of the spectrograph with a line scan camera;

6 a representation of signals measured with the spectrograph;

7 a representation of a remission for two different types of paper;

8th a representation of a remission for two different types of paper in the second derivative; and

9 a schematic representation of an inventive embodiment of the spectrometer with a row of lamps, a line of measuring optics in the measurement of products in transmission on a slide in a section from top to bottom through the direction of movement of the material flow.

In the embodiment according to 1 and 2 is a line of halogen lamps 1 in a first focal line of an elliptical cylinder mirror 2 arranged. The of these light sources 1 emitted light rays 8th be in a second focal line of the concave mirror 2 focused, through the materials or objects 12 , on a conveyor belt 13 lying and forming a material or object stream, be moved. Both focal lines are perpendicular to the plane through the in 1 drawn crossing points of the measuring radiation. Focusing on the second focal line produces a radiation waist, which in the present example has an extension of about 3 cm.

In the in the 1 and 2 shown example, plastic containers are presented from household waste, the material composition is to be measured for subsequent sorting. That of the materials or objects 12 remitted light 9 is characteristically changed in composition and passes through a series of measuring optics consisting of lenses 4 and downstream optical cables 3 , to an optical multiplexer, not shown here.

The optical multiplexer is in the DE 198 60 284 described in detail. The multiplexer has 64 Inputs for fiber optic cables and four inputs, which are used for dark signal measurement. The optical multiplexer switches all optical cables at high speed 3 one after the other on the entrance 20 of the spectrograph, presented in 5 ,

In other, not shown embodiments of the invention, the light guide 3 even without lenses arranged in front of it 4 as light-receiving optics 3 . 4 be used for the spectrometer shown.

The light-receiving optics 3 . 4 are, as in 2 represented, at a distance of 5 cm in a line transverse to the direction of the conveyor belt 13 or the object stream 12 lined up. The light-receiving optics are 3 . 4 and the light sources 1 which also has a line across the object stream 12 form, alternately arranged. The optical axes of the light-receiving optics run perpendicularly through the object stream. To avoid reflections on the surface of the objects to be measured, it may be advantageous to tilt these optical axes and the plane of symmetry of the elliptical cylinder mirror to the material flow. In this case, an angle to the vertical irradiation of greater than 1/4 of the opening of the irradiation should be set.

For example, the light-receiving optics as in 2 alternating with the light sources 1 be arranged, each in the space between two light sources 1 a fiber optic cable 3 is provided. However, in other embodiments of the invention, two or more light sources could also be used 1 be arranged next to each other and then only one or more Lichtaufnahmeoptiken 3 . 4 be provided. It is also possible that several light-receiving optics 3 . 4 between individual light sources 1 are provided. Depending on requirements, even within the rows, the arrangement of light sources 1 and light-receiving optics 3 . 4 be different, but in total an alternate arrangement is to be realized.

Because of the light-receiving optics 3 . 4 alternating with the light sources 1 lined up, the light reflected or reflected from the materials or objects can be 9 directly without deflecting mirror on the light-receiving optics 3 . 4 and from there are transmitted directly to the spectrograph. It thus results for the remitted or reflected light 9 a short optical path, reducing the intensity of the light-receiving optics 3 . 4 recorded light 9 is correspondingly high. The light sources 1 therefore have to light compared to the prior art 8th with a lower intensity on the materials or objects 12 of the object stream radiate, whereby the spectral analyte device heats up significantly less during operation, as is the case with known devices.

In the present presentation of 2 is a section with 5 measuring optics of a total of 32 measuring optics shown, which are arranged over a band about 1.60 m wide. The measuring head line controls the entire band with a grid of 5 cm. The measuring track width is about 2.5 cm. If the objects to be measured become smaller than about 5 cm, it is necessary to reduce the pitch to the measuring track width. In this case, 64 measurement optics are arranged in a row with a grid of about 2.5 cm across the 1.60 m wide band.

The multiplexer switches the individual 32 or 64 optical cables in succession at 80 Hz 3 on the spectrograph. Thus, tapes can still be measured gap-free at a speed of about 2.00 m per second. The lines of halogen lamps 1 and measuring optics 3 . 4 are installed in a housing, the bottom of a measuring window 5 and laterally cooling fins 7 has. If the band allocation is missing, a swivel arm can be used to calibrate the measuring system 10 around a rotation axis 7 be swung so that at the location of the products to be measured a calibration ceramics 11 is arranged. In the exemplary embodiment, an Al ₂ O ₃ ceramic with a remission of about 70% is used.

In the embodiment according to 3 and 4 is a line of halogen lamps 1 in the first focal line of an elliptical cylinder mirror 2 arranged. The of these light sources 1 emitted light rays 8th are focused in the second focal line of the concave mirror, which is in the measurement window 17 lies about which materials or objects, such as the products 16 that in the example shown contain paper products from the waste, slip. The radiation waist or focus width in the measurement window 17 is about 3 cm. The slide 18 joins a conveyor belt, not shown here 13 the products in a wide flow of material onto the chute 18 promotes.

In the example shown, the chute is made 18 made of stainless steel and has a receptacle for the measuring window 17 on. In other, not shown embodiments of the invention, the chute 18 also from another material or with already integrated measurement window 17 be made.

In 3 and 4 is represented as an example of the waste paper to be evaluated by the device according to the invention or the corresponding method, which is to be evaluated and sorted according to the paper quality. That of the objects 16 remitted light 9 is characteristically changed in composition and passes over the series of measuring optics, consisting of the entrance openings of optical cables 3 to the optical multiplexer.

In the presentation of 4 is a section with 4 measuring optics from a total of 64 measuring optics shown under a slide about 3.20 m wide 18 are arranged. The measuring head line controls the width of the chute 18 with a measuring track width of 5 cm. The optical multiplexer switches the following 64 optical fiber cables sequentially in succession to the following spectrograph at 40 Hz 3 on. Thus, the waste paper can still be measured without gaps at a speed of about 2.00 m per second.

The lines of halogen lamps 1 and measuring optics 3 are installed in a housing, which is not shown. The measurement window 17 has on the products 16 opposite side a rough surface 19 , so that accounted for a few percent of the measuring radiation 8th on this surface 19 is scattered. A portion of this scattered radiation passes through the series of measuring optics 3 and the optical multiplexer in the spectrograph shown in 5 , Missing objects or materials on the measurement window 17 What occurs in the ongoing production process at intervals, this scattered light is used for calibration of the measuring system.

The output of the optical multiplexer is directly to the inlet 20 Coupled with the spectrograph. It is also possible to connect them via a fiber optic cable.

As in 5 is shown, the light passes from the objects of this inlet opening 20 on a holographic concave grating 21 that in the exit plane 22 of the spectrograph, the light decomposed according to the wavelength as a spectrum. In the present example, a spectrum is generated in the wavelength range between 1400 and 2400 nm. In general, the arrangement described is suitable for a wavelength range from 190 nm to 2500 nm. In the exit plane of the spectrograph is a camera 23 arranged with an InGaAs photodiode array, which converts the light spectrum into electrical measurement signals. The measuring signals are stored, normalized and evaluated in a computer belonging to the spectrometer. From the measurement results, the characteristics characterizing the samples are derived. In the present case, a line camera with 256 photodiodes in a row is used, which detects a wavelength range of 1404 to 1914 nm.

6 shows a diagram, wherein examples of measured by the line scan spectra are plotted as photodetector signals versus the wavelength. The signals of the photodiodes are given in counts, as they arise in a conversion of an analog to a digital signal. If light is kept away from the spectrograph, one measures the dark signal, which results from the dark current of the photodiodes and the set offset of the following analog electronics. The dark signal is repetitively measured in the present embodiment and subtracted from the measurement signals.

The trace 24 shows the measurement signals to the arrangement 3 if there is no paper on the measuring window 17 , They will be out of the window 17 on the surface 19 formed in the measuring channel scattered light. If one applies a calibration ceramic with a remission of 65% in the entire spectral range to the measurement window, one obtains the measurement curve 25 , which are dominated by the spectral properties of the spectrometer of the so-called device function.

The at the measurement window 17 Scattered light has an approximate cosine distribution which, calibrated with the calibration ceramics, gives a reflectance value of 15% in the wavelength range used and also describes the device function of the spectrometer.

The measured curves 26 and 27 show the signals from newsprint and office paper passing through the measurement window 17 slipped. They are not meaningful for the remission of paper, since the measurement curves are dominated by the device function.

The characteristic remission of the objects, in this case of paper, must be separated from the device function by mathematical operations. The signals from the scattering window 24 are referred to as I _S (λ), the signals from the ceramic standard 25 as I _K (λ) and the signals from the products 26 . 27 as I _p (λ). The remission of the sample can be calculated to a good approximation according to the following relationship: R p (λ) = K · I p (Λ) / I S (λ) expressed in%

Since the remission value of the ceramic in the entire spectral range is known to be 65%, K can be calculated according to the following relationship: K = 65% · I S (Λ) / [I K (λ) - I S (Λ)]

7 shows the calculated in this way remission of the measured newspaper and office paper 28 and 29 as a function of wavelength, expressed in%.

Because the scattering properties of the window 17 do not change over time and the window 17 When the factor K is completely spectrally neutral, after determination of the factor K, the device can be timely in the absence of a sample via the scattered light on the window 17 calibrate yourself. A time-consuming and erroneous calibration with standards for measuring the samples can be dispensed with. The reproduced reflectance spectra are dominated by the strong absorption bands of the water content in the paper at 1460 and 1920 nm and, unprocessed, show no absorption bands of other paper constituents.

For their visualization, the second derivative of the spectra formed in 8th is shown. The absorption bands form narrow maxima in the second derivative. The remission spectra of newsprint 30 and of office paper 31 show absorption bands of cellulose at wavelengths of 1428, 1482, 1500, 1587, 1704, 1773 and 1831 nm. The newsprint also shows a strong band at 1677 nm, which has a high content of lignin. A strong band at 1410 nm is caused by a high content of calcite. The lignin content points to a wood-containing paper. The high calcite content indicates that coated paper is present. Based on this information, the paper is sorted for reprocessing.

In 9 are transparent plastic films as an example of the materials or objects to be evaluated with the device according to the invention or the corresponding method 32 whose layer composition is to be determined and which should be sorted according to the layer structure and. The measurement of the films is carried out in transmission.

A conveyor belt 33 promotes the plastic films to be sorted 32 on a slide 18 in which a measurement window 34 is installed. That from the row of light sources 1 emitted light 8th is about an elliptical cylindrical mirror 2 on a set of fiber optic cables 3 focused. The radiation penetrates the transparent films to be measured 32 as well as the measurement window 34 , That of the objects 32 Absorption-modified light passes through the optical cables 3 to an optical multiplexer. The advantage of this measuring arrangement over the above-discussed arrangements in reflection is a particular insensitivity of the measurement to interferences, which superimpose the absorption spectra with thin transparent films and make a reliable determination of the objects impossible. A further advantage is a low dependence of the measurement results on the position of the objects, since the radiation characteristic is not changed by the objects and the light path length in the object is independent of the position.

In another, not shown embodiment of the invention, the above-described measurement in transmission can also be performed when the light sources 1 above a discharge curve for the object current and light-receiving optics 3 . 4 are provided below the discharge curve for the object stream.

The inventive method and the corresponding device are particularly suitable for the Composition of fast moving raw materials or products to determine in a wide material flow. The procedure and the Device can for example, in the sorting of waste, in quality control in production as well as in the evaluation of raw materials and natural products be set. With the device according to the invention and the corresponding Procedures can Products in a wide flow of material and in rapid motion by a measurement from above on a transport device, by a Measurement from below through a measuring window in a chute or in the be measured free flight.

All in all is the device according to the invention designed in such a way that the used measuring head row is spatially compact and with respect to the Technology and costs can be made with little effort.

The Invention allows Furthermore, that the measuring technology used without much effort can be calibrated promptly. In addition, the spectral distribution independent of the measured curves exactly determined by the spectral properties of the spectrometer become. Despite the compact and simple construction of the device according to the invention, the Materials or objects safely identified in a stream of objects or the material composition of objects can be determined safely. By the above-described special arrangement possibilities of the invention is it also possible the additives to the materials of the objects in a stream of objects down to the trace area can be measured safely.

Claims (17)

Device for the spectral-analytical evaluation of materials or objects ( 12 . 16 ) in a material or object stream, with multiple light sources ( 1 ) and several optics, with which of the materials or objects transmitted, remitted or reflected light ( 9 ) is transmitted to a spectrograph, wherein at defined intervals and transversely to the material or object stream ( 12 . 16 ) Light sources ( 1 ) are lined up in a row, characterized in that alternately to the light sources ( 1 ) Light-receiving optics ( 3 . 4 ) are arranged such that the optical axes of the light receiving optics ( 3 . 4 ) in the plane of symmetry of the light irradiation ( 8th ) and the light sources ( 1 ) in a first focus of an elliptical cylindrical mirror ( 2 ) are arranged. Apparatus according to claim 1, characterized in that the material or object flow through a second one-dimensional focus of the cylinder mirror ( 2 ) runs; and that the optical axes of the light-receiving optics ( 3 . 4 ) are perpendicular through the second one-dimensional focus. Device according to at least one of the preceding claims, characterized in that the light-receiving optics ( 3 . 4 ) Optical fiber cable ( 3 ). Apparatus according to claim 3, characterized in that the inlet openings of the light guide ( 3 ) directly or with at least one lens or lens combination ( 4 ) are directed to the second one-dimensional focus. Device according to claim 2 or 4, characterized in that the light sources ( 1 ) and the cylindrical mirror ( 2 ) below one in a transport device ( 13 ) for the material or object stream provided measuring window ( 17 ) are arranged such that light ( 8th ) through the measurement window ( 17 ) and the second focus of the cylinder mirror ( 2 ) in the measurement window ( 17 ) lies. Apparatus according to claim 5, characterized in that the measuring window ( 17 ) Has light-scattering properties. Device according to claim 2 or 4, characterized in that the light sources ( 1 ) above a transport device ( 13 ) for the material or object flow or over a discharge curve of the transport device ( 13 ) are arranged, wherein the transport device ( 13 ) or the trajectory is such that overhead surfaces or regions of the materials or objects ( 12 . 16 ) on average in the second one-dimensional focus of the cylinder mirror ( 2 ) lie. Apparatus according to claim 7, characterized in that the light receiving optics ( 3 . 4 ) above the transport device ( 13 ) for the material or object flow or over the discharge curve of the transport device ( 13 ) are arranged. Apparatus according to claim 7, characterized in that the light receiving optics ( 3 . 4 ) below a measuring window provided in the transport device for the material or object stream ( 34 ) is arranged. Apparatus according to claim 5 or 9, characterized in that the measuring window ( 17 . 34 ) in a slide ( 18 ) for the materials or objects ( 12 . 16 ) is provided. Method for the spectral analytical evaluation of materials or objects ( 12 . 16 ) in one Material or object current, with multiple light sources ( 1 ) and several optics, with which of the materials or objects ( 12 . 16 ) transmitted, remitted or reflected light ( 9 ) is transmitted to a spectrograph, light being emitted from light sources arranged at defined intervals and transversely to the material or object stream ( 1 ) on the material or object stream ( 12 . 16 ) and alternately to the light sources ( 1 ) arranged light receiving optics ( 3 . 4 ) transmitted, remitted or reflected light from the material or object stream ( 9 ), characterized in that the optical axes of the light-receiving optics ( 3 . 4 ) in the plane of symmetry of the light irradiation ( 8th ) and that of the light sources ( 1 ) radiated light ( 8th ) with an elliptical cylindrical mirror ( 2 ) on the material or object stream or the transport device ( 13 ). Method according to claim 11, characterized in that the light sources ( 1 ) emitted light beams ( 8th ) in a second focus of the cylinder mirror ( 2 ) through which the materials or objects ( 12 . 16 ) are moved. Method according to claim 11 or 12, characterized in that of the materials or objects ( 12 . 16 ) transmitted, remitted or reflected light from optical cables ( 3 ) directly or with at least one lens or lens combination ( 4 ) and directed to the spectrograph. Method according to claim 11 or 12, characterized in that the light ( 8th ) of the light sources ( 1 ) so on the transport device ( 13 ) or a discharge curve of the transport device ( 13 ) is emitted, that overhead surfaces or areas of materials or objects ( 12 . 16 ) on average in the focal plane of the cylinder mirror ( 2 ) lie. Method according to claim 11 or 12, characterized in that the light ( 8th ) of the light sources ( 1 ) by a in the transport device ( 13 ) provided for the material or object current measuring window ( 17 ). Method according to claim 12, characterized in that at least one remission standard ( 11 ) in the second focus of the cylinder mirror ( 2 ), that spectral transmission, remission or reflection values of materials or objects ( 12 . 16 ) with measured values of the remission standard ( 11 ) and that the normalized spectral measured values of individual measuring channels are used for the spectral-analytical evaluation of the materials or objects detected in the measuring channels ( 12 ) be used. Method according to claim 13 and 15, characterized in that light which is emitted at the measuring window ( 17 ) is spread over the fiber optic cables ( 3 ) is guided to the spectrograph, is detected there and in the case of missing materials or objects ( 16 ) on the measurement window ( 17 ) for the normalization of the measured spectral transmission, remission or reflection of the materials or objects ( 16 ) is used as remission standard in individual measurement channels.