EP3254098A1

EP3254098A1 - Method and arrangement for analysis of a material flow

Info

Publication number: EP3254098A1
Application number: EP15831128.2A
Authority: EP
Inventors: Hermann Wotruba; Kilian NEUBERT; Tobias Vraetz; Franz Domenic Boos; Karl Nienhaus; Ralph Baltes; Henning Knapp
Original assignee: Rheinisch Westlische Technische Hochschuke RWTH
Current assignee: Rheinisch Westlische Technische Hochschuke RWTH
Priority date: 2015-02-03
Filing date: 2015-11-25
Publication date: 2017-12-13
Also published as: DE102015101537A1; AU2015381355A1; WO2016124165A1; US20180017420A1

Abstract

The invention relates to a method and to an arrangement for analysis of a material flow (S) which consists of one or more material components. The material flow (S) is conducted via a conveyor line. One or more acoustic sensors (6-11) are allocated to the conveyor line. Acoustic signals produced by the material flow (S) are detected by the acoustic sensor(s) (6-11) and then converted into digital signals. The digital signals are analyzed in an evaluating unit in a computer-assisted manner and analyzed by means of an algorithm in comparison to reference values specified based on individual identifying characteristics of the material components, such that the material components are identified and the mass fraction of at least one material component in the material flow (S) is determined.

Description

Method and arrangement for analyzing a material flow

The invention relates to a method for analyzing a material flow and to an arrangement for carrying out the method.

In the context of the invention, a stream of substances is a stream of one or more solids, in particular of primary and / or secondary mineral raw materials, including metals. A material stream can also consist of or contain plastics. Furthermore, a stream of waste products, in particular from industrial waste products such as slags, ashes and other residues may consist of an industrial utilization. Global growth, especially in industrialized and emerging countries, is leading to a steady increase in demand for raw materials. Most of the necessary raw materials are currently being made available through the use of primary non-renewable raw materials. The challenge of the primary raw materials industry is to be able to meet the increasing demand for raw materials despite decreasing recyclables and more complicated reservoir conditions. At the same time, it is essential that the use of existing resources be made as efficient as possible in terms of sustainability. These conditions demonstrate the need to develop and exploit new innovative processing technologies for the efficient exploitation of existing resources.

The fewest mineral raw materials have a sufficient purity directly after the mining extraction, which makes it possible to further process them directly in subsequent processes. Therefore, mineral raw materials usually have to be treated by the mineral extraction process by physical treatment processes. Depending on the extracted raw material type, different processes are used to process the raw materials or minerals. After obtaining and transporting the raw materials to the processing plant, the minerals undergo various process stages of physical processing in accordance with the requirements of the end product with regard to purity and valuable substance concentration. These include, among others, the crushing, classification and sorting of minerals. A detailed knowledge of the composition and properties of reactants and products of individual process stages in a treatment plant is important in order to be able to operate treatment processes as efficiently as possible. In particular, the statement about recyclable material and density distribution in educt and product streams is of particular importance for evaluating, controlling and regulating treatment processes.

Therefore, in the processing of mineral raw materials, it is important to have as much knowledge as possible about the properties and the chemical composition of the processing raw material in order to ensure efficient processing. As a rule, it is one of several components formed stream of one or more valuable minerals, which may still have to be digested from a grain and one or more accompanying components, especially accompanying minerals. Is the Stoffstrombzw. Material composition and the mass distribution of a multicomponent material flow known, subsequent processes can be better controlled.

For the determination of the density of a material flow, an offline analysis and an online analysis is currently known, wherein an online analysis has a variety of advantages over a conventional offline analysis. Currently, however, it is only possible to determine the average density of a material flow online, for example by using a laser triangulation and a belt scale. For some raw materials, it is also possible to indirectly infer to an average density, such. B. by determining the ash content of coal. However, only the density distribution provides a more accurate statement about the raw material than the average density, because only the density distribution, that is the statement about a mass distribution of particles with different density in the material flow makes it possible to evaluate the efficiency of previous process steps or subsequent process steps by suitable automation technology better adapt.

The current state of the art for determining the density distribution is the floating-sink analysis in a liquid medium. A sample is made to float in a high density liquid. Gradually, the density of the liquid is reduced, so that more particles or material components sink. However, this analysis often takes several hours and is therefore not suitable for a statement about the system efficiency and thus suitable for a short-term process control.

A major disadvantage of known analysis methods is that an analysis of the material flows is only possible offline. This is clear, for example, in a stream that consists of a mineral combination of gypsum and anhydride and the substance components gypsum and anhydride in various mass distribution. The mineral gypsum [CaS0 ₄ * 2H ₂ 0] is often associated with mineral anhydride [CaS0 ₄ ] due to its genesis in many reservoirs. For the processing steps, it is important not to exceed a specified limit of anhydride, as this would otherwise lead to quality losses in subsequent product stages and its use. Currently, it is possible to determine the water of crystallization and thus the amount of anhydride thermogravimetrically. However, this process takes several minutes and is limited to individual samples. The delay between sample name and analysis until the analysis results are obtained means that changes in the composition are detected only late. Due to this time delay, it is not possible to control or regulate downstream or upstream processes.

The pre-described problem also applies to other streams that contain different material components in different mass fractions, such as streams of coal and adjacent rock.

The invention is based on the prior art based on the object, an application technology advantageous method and an arrangement for analyzing a material flow show that online, ie during operation, a recognition of the substance contained in the flow of material and determination of the mass fraction of at least one substance component allowed in the flow.

The solution of the procedural part of the task consists in a method according to claim 1.

The solution of the objective part of the object is achieved by an arrangement for carrying out the method according to claim 5.

In the method according to the invention, a stream is passed over a conveyor line. The conveying path is assigned at least one sound sensor, by which acoustic signals generated by the material flow are detected. The acoustic signals are converted into digital signals and forwarded to an evaluation unit. In the evaluation unit, a computer-aided evaluation of the digital signals is performed by means of an algorithm in which a comparison of the digital signals with Reference values are carried out, which are determined on the basis of or based on individual recognition characteristics of the substance components. At least one substance component is identified by the evaluation unit and its mass fraction is determined in the material flow.

The evaluation unit has the appropriate means for the identification of the components and the determination of the mass fraction of one or more substance components in the flow. The necessary arithmetic and logical operations are performed in the evaluation unit in chronological and logical order. The results are output and / or displayed via suitable means and, if appropriate, used directly or indirectly for controlling the material flow or influencing the flow of material.

The invention enables early detection and analysis of the material flow and its composition and the mass distribution of the individual components in the material flow. As a result, the control of downstream processes is significantly improved. The monitoring of a material flow leaving a sorting process also provides possibilities for regulation. The resulting savings in direct and indirect costs lead to an increase in competitiveness.

As already mentioned in the introduction, a material stream in the context of the invention is a stream of one or more substance components. This may be one or more solids, in particular of primary and / or secondary mineral raw materials including metals. Such a stream arises, for example, in the miner mining of mineral resources such as gypsum and anhydride or coal, as well as, for example, fluorspar and barite, iron ore, non-ferrous metals or bauxite.

The stream consists regularly of at least two components, each of the components can be contained in a proportion of 0% to 100% in the stream. The inventive method and the arrangement are therefore also able to identify a stream that consists only of a substance component. In practice, however, the material flow exists predominantly of one or more substance components which are contained in the mass flow in different mass distribution.

The material stream to be analyzed may also be a stream of material diverted from a larger stream.

The material flow is continuously moved over a conveyor line. The conveyor line is in particular part of a continuous conveyor or integrated in a continuous conveyor. The conveyor line can be for example a conveyor belt, a conveyor trough, a vibrating trough, a vibrating chute, a pipeline or even a free-fall conveyor unit or form part of this.

The conveyor line is assigned at least one sound sensor. The at least one sound sensor may be a sound emission sensor, a structure-borne sound sensor, an airborne sound sensor or a liquid-sounding sensor.

One aspect of the invention provides for the allocation of a plurality of sound sensors, in particular sound sensors of different types, that is to say in particular a combination of a sound emission sensor and / or a structure-borne sound sensor and / or an airborne sound sensor and / or a liquid-sound sensor.

The one or more sound sensors detect acoustic signals generated by the material flow. Acoustic signals are acoustic events in the form of sound waves, which are generated during the movement of the material flow relative to the conveyor line.

Acoustic emission (AE) measurement is a process which has its origin in the non-destructive testing of materials. AE signals are caused by changes in the metal structure as a result of external stresses. Causes can be damage mechanisms such as crack initiation, crack growth, crack unification or even friction. When such a signal is generated, a small amount of energy is released in a short time. This pulse is in the s range, so scanning in the megahertz range is required. Typical frequencies of an acoustic emission signal are in the range greater than (>) 80 kHz to 2 MHz. Structure-borne sound is analogous to Acoustic Emission, a form of sound that propagates in a solid. The frequency range of classical structure-borne noise can be represented here from a few Hz (<0, 1 Hz) to the high kHz range (approximately 20 kHz). Classically, structure-borne noise analysis is used in condition monitoring of machinery.

In addition to the structure-borne noise, airborne noise is also to be perceived in the immediate vicinity. The information content of this signal usually results from the structure-borne noise signal, but the influence of different spatially separated signal sources can also be considered by means of airborne sound. For this purpose, provision is made in particular for the sound sensor or sensors to be or are arranged on a contact body of the conveying path or on a contact body incorporated in the conveying path. The material flow comes into contact with the contact body during the movement over the conveying path. The acoustic signals generated in the form of sound waves are detected by the sound sensor (s). Such a contact body may be, for example, a baffle plate or an element or component of a continuous conveyor, such as a bottom plate, a chute, or even a container or a container wall. In particular, the contact body is arranged physically separated within the conveying path. Airborne sound sensors detect signals which could not be detected with a single structure-borne sound or sound emission sensor.

Depending on the material flow to be analyzed and the conveying medium as well as the design of the conveying path, it is also possible to use liquid-sound sensors.

The identification, ie detection of the individual components and the determination of the mass fraction of one or the respective substance components in the flow is based on individual recognition characteristics of the fabric components. These are stored in the system.

If the term "system" is used below, the term "method according to the invention" and the arrangement according to the invention including the associated components are understood to mean both individually and collectively. Individual recognition features are in particular physical properties of the substance components such as density, hardness or modulus of elasticity. On the basis of these identification features, individual characteristics, such as curves, are defined for the individual substance components and stored in a database or the evaluation unit. The process is for this purpose on individual Einsatzbzw. Use cases adapted. The system is thus tuned to the expected in a flow of different material components and trained.

The invention enables a material-specific differentiation of material components of a material flow, for example, bulk materials such as gypsum and anhydride and a determination of the mass distribution. Thus, for example, a density distribution determination of coal and by-products as well as ores in a stream is possible. Collecting the density distribution of raw materials in coarse state alone allows data to be collected for the control and regulation of treatment processes.

Another advantage is the distinction of the substance components in the material flow. Consequently, a material detection for material types such as gypsum and anhydride is possible. Further applications may be, for example, the separation of industrial minerals such as halite and sylvenite. The use of the method according to the invention and the arrangement in the processing of iron ore is also promising. In particular, the determination of the density distribution can expect advantageous results.

The material recognition and mass distribution takes place via the evaluation of sound emission (AE), structure-borne noise and / or airborne sound signals and / or liquid-sound signals. These are rated both in the time and in the frequency domain.

The measurement data acquisition of the at least one sensor, preferably a plurality of sensors, takes place synchronously in time via a single evaluation unit. This ensures that the signals can be synchronized with each other. With the help of a control signal the measuring system should during the recording of the Data to be checked for its functionality. The sensors can be connected individually, so that an assessment of the material flow, for example, can only be made on the basis of structure-borne noise emission sensors.

Through the combination of different statistical parameters, characteristic values can be defined with which a characterization of the material flow and thus of the composition is possible. The development of the characteristic values, depending on the material to be characterized, can take place both at a test stand and during the ongoing process within a company. To calculate the characteristic values, the parameters of one sensor, preferably of a plurality of sensors, are fused and the corresponding algorithm is stored on the computer for evaluation. The parameters are calculated block by block for block flow intervals defined as a function of the flow stream.

The algorithm used involves the calculation and evaluation of one or more of the following parameters:

- Arithmetic mean

- median

- variance

- standard deviation

- RMS value (Root Mean Square)

- Square mean / RMQ value

- RMX value

Crest factor (crest factor)

- Kurtoris factor (warping factor)

- maximum value

- Peak2RMS value

- Peak2Peak value.

For the calculation of specific characteristics and thus for the characterization of material flows during the ongoing preparation process, one or more of the following explained parameters can be integrated into the evaluation: Arithmetic mean:

The mean value describes the statistical average value and is one of the positional parameters in the statistics. For the mean, add all the values of a data set and divide the sum by the number of all values.

N

i π

i = l with:

^{: ϊ:} arithmetic mean

i ^¥ number of values

x i-th value

Median:

The value that lies exactly in the middle of a data distribution is called median or central value. One half of all individual data is always smaller, the other larger than the median. With an even number of individual data, the median is half the sum of the two values in the middle. even for N odd for N straight

with: ^x median

^N number of values

variance:

The variance is a spread measure that characterizes the distribution of values around the mean. It is the square of the standard deviation. The variance is calculated by dividing the sum of the squared deviations of all measured values from the arithmetic mean by the number of measured values. With:

^{3 "} variance

^N number of values

^A \ i -th value

x Arithmetic mean of all values Standard deviation:

The standard deviation is a measure of the spread of the values of a feature around its mean (arithmetic mean). Simplified, the standard deviation is the average distance of all measured values of a feature from the average.

With:

standard deviation

N number of values

i-th value

X Arithmetic mean of all values

RMS:

With:

SMS rms / square mean

Number of values i-th value

RMQ value:

With:

RMQ RMQ value (root mean square)

^AT number of values

x, i-th value

RMX value:

With:

RMX RMX value

^ΛΤ Number of values

^A \ i -th value

x power of weighting

Crest Factor:

The crest factor describes the ratio of maximum amplitude to RMS value within a range. with: c crest factor Number of values

i-th value

Kurtosis factor:

With:

Kurtosis factor

Arithmetic mean

Number of values

i-th value

In addition, the block-by-block determination of the following parameters takes place for each interval range.

Maximum value:

The maximum value corresponds to the largest number of elements within the block interval:

MAX = ffissfx)

Peak2 RMS value:

The block-wise Peak2RMS value is calculated from the ratio of the maximum value to the RMS value within one block interval.

P2R = -

RM5 {x)

Peak2Peak value:

The block-by-peak Peak2Peak value is calculated from the difference between the maximum value and the minimum value within a block interval. Alternatively, characteristic bursts can be extracted from the AE measurement data in the time domain. A burst is a so-called transient AE signal. In this case, the beginning and end clearly stand out from any background noise. These bursts have a characteristic waveform, as shown by way of example in FIG. The aim is the detection of such bursts and the evaluation of AE signals of the characteristics described (RMS, Peak2Peak, etc.). Derived characteristic values from the bursts (maximum amplitude, rise time, decay time, duration of a burst) can also be used to determine the material distribution. The algorithms developed for the detection of bursts autonomously detect AE events in the time and frequency domain and are characterized as follows:

1 . Edge Detection:

The edge detection method makes use of characteristic properties of the AE signals. For this, the algorithm searches for regions in the AE signal with high gradients of the signal, which can be marked as the beginning of an AE event due to the short rise time of AE bursts. The algorithm looks for areas within the AE signal where the envelope has high gradients (rising edges). First, the calculation of the envelope of the AE signal including rectification and low-pass filtering of the raw signal takes place. Subsequently, the distribution of the envelope into subsections as well as the partial calculation of the individual gradients takes place. If the derivative exceeds a threshold, the interval is detected as part of a high rising portion of the signal. Continuous areas of strongly increasing slope are collectively counted as the beginning of a burst. As a final step, the algorithm determines the end of a burst over a defined threshold.

2. Shifting Windows:

The Shifting Windows algorithm uses a window for burst detection, which is moved across the entire data set. At each step, local maxima are detected. These are in turn used to describe the bursts. A burst occurs when an extreme amplitude change occurs in the data set. Thus, the change in amplitude as a local extremum or a local maximum are interpreted. Windowing can limit the amount of data to be checked. The maximum value and its position can thus be found faster within the data set and marked as a potential burst. The window begins viewing at the beginning of the data set and is shifted on the corresponding axis with a defined increment as a function of time. A window is in this case a section of the present data set, which is examined at the respective time. In order not to erroneously recognize and store regular local maxima as bursts, the RMS values of adjacent windows are compared. This method completely dispenses with the definition of static characteristics. First attempts with both conventional data loggers and AE based data loggers have already confirmed the robust and reliable functionality of the algorithm.

3. Frequencv detection:

In the Frequency Detection method, an AE measurement signal is analyzed in defined time intervals in the frequency domain. The mode of operation of the AE sensors is based on the resonance principle. For this reason, it can be seen that an increase in the frequency amplitudes always happens exactly when a characteristic AE burst has taken place. As a result, it is possible to detect a burst using the frequency range of a signal. Experiments with the measurement methods already mentioned have shown that dominant frequencies can be detected both at about 100 kHz and at about 300 kHz. Finally, the burst is transferred to the time domain.

An essential aspect of the invention provides that the algorithm for detecting and evaluating bursts is applied by means of edge detection, shifting window, frequency detection. Afterwards an evaluation of the individual bursts will be carried out. This evaluation of the bursts is based on characteristic values, in particular on the basis of one or more of the following parameters: maximum amplitude, rise time, decay time, duration of a burst and parameters derived therefrom. In the following, again some essential advantages of the invention are summarized:

Acoustic emission and structure-borne sound technology as well as airborne or fluidborne sound can be used in various areas of the processing of mineral raw materials. The technology can be used to perform subsequent processes more efficiently by accurate and rapid analysis of the raw materials. An inference of the density distribution can be used to control or regulate existing processes in real time. As a result, products from a wide variety of treatment processes can be evaluated and the plants can be adapted, but also the analysis of the input stream in a treatment process with subsequent control of the processes is conceivable. Thus, density sorting can be optimized by means of setting machines, which is one of the most frequently used processes in the field of mineral processing, in that it can react directly to fluctuating raw material characteristics by adapting machine parameters. Here the focus is on the detection of the density distribution of the bulk material to be sorted, on the basis of which the machine can subsequently be controlled and regulated by means of suitable automation technology. Even minor adjustments ensure optimized qualities of the manufactured products and additionally increase the recycling of the used processes. This reduces the loss of valuable strategic resources and optimizes the utilization of existing deposit reserves. An efficient control and regulation of setting machines, based on a determination of the density distribution, is currently not possible and would provide a decisive and valuable contribution in terms of increased resource efficiency and improved utilization of existing resource reserves.

In addition to the above-mentioned control and regulation of treatment processes, it is also possible to use these sensor types for direct material flow sorting and mixing of bulk materials. Raw materials such as gypsum [CaS0 ₄ * 2H ₂ 0] and anhydrite [CaS0 ₄ ] are currently difficult to distinguish from one another based on their chemical composition. Existing processes such as thermogravimetry can only be implemented in the laboratory and are very time-consuming, so that a timely analysis and adaptation of processes are not feasible. The inventive method and arrangement allow a rapid analysis of a stream of raw materials and creates the conditions for optimizing in particular the mixing ratios of whole streams, even with difficult to distinguish types of raw materials. An exact statement about mixing ratios and the composition of material flows means that treatment processes can not only be operated cost-optimized, but also better use of available raw material reserves.

The invention can be utilized in different ways. On the one hand, a possibility is to be created in advance of distinguishing difficult-to-distinguish types of raw materials by means of sensors and thus enabling optimized process control. One potential application is the gypsum industry. There is a need to develop a technology for the online analysis of gypsum and anhydrite, allowing a more accurate mix of different types of raw materials. Setting accurate mixing ratios results in gypsum products having specified quality parameters being made cheaper because the less expensive anhydrite can be accurately fed to the mixture to the desired limit.

Another promising field of application of the invention is the non-destructive and rapid characterization and evaluation of large-volume bulk materials in a sorting process. There is special potential in the optimization of density sorting processes by means of a jigging machine. By combining the obtained measurement data of the sensors with adapted automation algorithms, a control technology for setting machines can be designed. Compared to previously used process evaluations, which are time-consuming and not feasible online, fast control and regulation and thus adaptation to changing material flow characteristics is possible within the scope of the invention. The invention provides the prerequisites to clearly distinguish the material components occurring in a stream from one another and to determine their mass fraction. In particular, an average density distribution can be determined. A Such measuring technology, adapted to the particular raw material, can in principle be used for any stream in which minerals or mineral mixtures occur which differ in their density. In addition to the processing of iron ore and coal, the treatment of the critical metals tungsten and tantalum should be mentioned as a possible field of application. The implementation into existing processes by measuring the task as well as the products of a process can be used to make adjustments in the current process and thus to increase the yield of valuable materials.

The invention is described below with reference to an embodiment, to which reference is also made to the accompanying figures. Show it:

Figure 1 is a schematic representation of a test stand according to the inventive arrangements to which the inventive method has been tested;

Figure 2 is a section through the figure 1 along the line A-A with a

Schematic representation of the provided there measuring point I;

FIG. 3 shows a detail of the representation of FIG. 1 in the region of one in the FIG

Conveyor integrated contact body and provided there measuring point II and

Figure 4 is a circuit diagram showing the signal processing in a method according to the invention and

Figure 5 shows an example of an acoustic emission signal with the representation of

Amplitude over time.

FIG. 1 shows a test setup on which the practical suitability of the method and the arrangement according to the invention has been tested and proven.

The arrangement comprises a conveyor line 1, which in the illustrated experimental setup comprises a vibrating trough 2, a conveyor belt 3 and a free-fall section 4. About a task unit 5 is a multi-component contained Mixture in the form of a stream S of the conveyor line 1 fed. The conveyor line 1 are a plurality of sound sensors 6, 7, 8, 9, 10, 1 1 assigned (see Figures 2 and 3).

In the arrangement shown here, a first measuring point I in the region of the vibrating trough 2 is provided. At the measuring point I below the bottom plate 12 of the vibrating trough 2 both a sound emission sensor 6 and a structure-borne sound sensor 7 and an airborne sound sensor 8 are arranged. The bottom plate 12 of the vibrating trough 2 as well as the side walls 13, 14 form a contact body with which the material components of the material flow S come into contact. The sound sensors 6, 7, 8 are arranged below the base plate 12 and do not come into direct or direct contact with the stream S itself.

From the vibrating trough 2, the stream S passes to the conveyor belt 3 and is dropped at the end 15 of the conveyor belt 3 and moves in free fall on the free fall track 4. The stream S then encounters a contact body in the form of a baffle plate 16, in the conveying path 1 is incorporated.

It can be seen that the baffle plate 16 is set at an angle relative to the vertical, so that the material flow S on the baffle plate 12 occurs at an angle. At the baffle plate 16, a second measuring point II is established. For this purpose, sound sensors 9, 10 and 1 1 are arranged on the back 17 of the baffle plate 16. The sound sensors 9, 10, 1 1 are also sound emission sensors, structure-borne sound sensors and / or airborne sound sensors.

The mixture of substances is passed as continuous stream S over the conveyor line 1. During the movement of the material stream S via the conveyor line 1, the individual substance component, that is to say the grains K of the material stream S, come into contact with one another. In addition, the material flow S comes into contact with the components of the vibrating trough 2, in particular its bottom plate 12 and the baffle plate 16 on this sound emissions are generated. Furthermore, these processes generate airborne and structure-borne noise emissions. The analysis of the stream S can be carried out both at the measuring point I, as well as at the measuring point II. There, acoustic signals in the form of sound emission, structure-borne noise and / or airborne noise are recorded. The measuring point I evaluates the material flow S while it passes over the vibrating trough 2. By vibrating the vibrating trough 2 several pulses are generated, which are used for the evaluation of the acoustic emission signal (Acoustic Emission) as well as the structure-borne noise and airborne sound. In the figure 2 structure-borne noise emissions are represented by the arrows a. The occurring airborne sound waves are marked with the letter b. The structure-borne sound waves are indicated by c. With the help of structure-borne noise signals, changes in the rigidity of the system (vibrating trough and material flow or material components) can be observed. With the help of all three information statements about the material flow composition can be made.

The measuring point II is located behind the conveyor belt 3 at the end of the free fall path 4 on the baffle plate 16. The sound sensors 9, 10, 1 1 are arranged on the back 17 of the baffle plate 16. The material flow S impinges on the baffle plate 16. In this contact of the individual substance components of the material flow S, in turn, the three sound signals can be observed or recorded, namely sound emission, structure-borne noise and airborne sound. Upon impact with the baffle plate 16, the impact pulse is significantly larger, which can lead to other evaluation algorithms. The vibration of the baffle plate 16 can be included as a further determining feature in the detection and evaluation.

Figure 3 shows an impact of the grain K of a substance component of the material flow S on the baffle plate 16 on impact sound emissions are generated by destruction of the material and the impact in the impingement pulse. This is illustrated by the letter a. Airborne sound waves generated by the process are indicated by b. Structure-borne sound vibrations of the vibrating trough 2 and the baffle plate 12 as a function of the rigidity are illustrated by the arrows c.

Even if three sound sensors 6, 7, 8 at the measuring point I and three sound sensors 9, 10, 1 1 at the measuring point II are shown in the exemplary embodiment explained here, a sound sensor 6, 7, 8, 9, 10, 11 can be provided be sufficient to detect the signals generated by the stream S. However, the combination of several sound sensors 6 - 1 1 in the region of a measuring point is advantageous. The acoustic signals generated by the continuous movement of the material flow S and recorded via the sound sensors 6 - 11 are amplified by means of an amplifier 18 (see FIG. 4) and converted into digital signals. For this purpose, an analog-to-digital converter 19, also called A / D converter, is provided. In an evaluation unit 20 linked to the system, a computer-aided evaluation of the digital signals is carried out by means of an algorithm in comparison to reference values determined on the basis of individual identification features of the substance components. For this purpose, the system components on a variety of substance or depending on the application or use case on the expected substance components learned. The reference values are stored in a database to which the evaluation unit 20 has access and which belongs to the system. The system has the ability to recognize in the set of data regularities, repetitions, similarities and laws and to compare them with the reference values stored in the system. By way of this, the substance components are identified and the mass fraction of one or more substance components of the material flow S is determined. In the context of practical experiments, in particular, the density of the material components has been found to be a particularly advantageous identifier.

As already explained, FIG. 5 shows the time characteristic of an AE signal with the representation of the amplitude over time. The bursts have a characteristic waveform. The aim of the evaluation of the AE signals is the comparison of the digital signals with reference values, which are determined on the basis of individual identification features of the components. This is done by means of algorithms. The algorithm (s) include the evaluation and evaluation of the parameters set forth in claim 3 (RMS, Peak2Peak, Peak2RMS, etc.). Derived characteristic values from the bursts as well as maximum amplitude, rise time, decay time and duration of a burst can also be used to determine the material distribution.

The system relies on the evaluation of a large number of bursts resulting from the movement of the material flow over the conveyor line. The bursts and their waveforms and waveform are evaluated. This requires the identification of meaningful characteristics. In this case, the determination (extraction) of the AE characteristics and the generation of an AE data record per burst takes place. In the In particular, the following AE characteristics can be included in identification and evaluation:

- Arrival time (absolute time of the first threshold crossing)

- maximum amplitude

Rise time (time interval between the first threshold exceedance and time of maximum amplitude)

- Cooldown

- Signal duration (time interval between the first and last threshold crossing) and further

- overshoot of a hit or count (number of crossing the threshold in one polarity)

- Energy (integral of the squared or absolute instantaneous values of the voltage curve)

- RMS (RMS) of the continuous background noise before the associated hit.

Reference numerals:

1 - conveyor line

2 - vibrating trough

3 - conveyor belt

4 - Free-fall track

5 - task unit

6 - sound sensor

7 - sound sensor

8 - sound sensor

9 - sound sensor

10 - sound sensor

1 1 - sound sensor

12 - floor panel

13 - side wall v. 2

14 - side wall v. 2

15 - end

16 - baffle plate

17 - back side

18 - amplifier

19 - Analog-to-digital converter 20 - Evaluation unit

K - grain

S - material flow

Claims

claims

1. A method for analyzing a stream (S), which consists of one or more material components, wherein the material flow (S) via a conveyor line (1) is guided, wherein the conveying path (1) at least one sound sensor (6-11) is assigned, by which the material flow (S) generated acoustic signals are detected, whereupon the acoustic signals converted into digital signals and in an evaluation unit (20) a computer-aided evaluation of the digital signals by means of an algorithm compared to based on individual recognition characteristics of the substance components determined reference values and the substance components identified and the mass fraction of at least one substance component in the stream (S) is determined.

2. The method according to claim 1, characterized in that acoustic signals in the form of acoustic emission (Acoustic Emission) and / or structure-borne noise and / or airborne sound and / or fluid sound are detected and evaluated.

3. The method according to claim 1 or 2, characterized in that the algorithm includes the calculation and evaluation of one or more of the parameters listed below:

- Arithmetic mean

- median

- variance

- standard deviation

- RMS value (Root Mean Square)

- Square mean / RMQ value

- RMX value

Crest factor (crest factor)

- Kurtoris factor (warping factor)

- maximum value

- Peak2RMS value

- Peak2Peak value.

4. The method according to any one of claims 1 to 3, characterized in that the algorithm for detecting and evaluating bursts is applied, whereupon an evaluation of the individual bursts is performed.

5. Arrangement for carrying out a method according to one of claims 1 to 4, with a conveying path (1) via which the material flow (S) relative to at least one sound sensor (6-11) is movable and the sound sensor (6 - 11) with a Evaluation unit (20) is linked, which means for identifying the material components and for determining the mass fraction of at least one substance component in the flow has.

6. Arrangement according to claim 5, characterized in that the sound sensor (6-11) is a sound emission sensor, a structure-borne sound sensor, an airborne sound sensor or a liquid-sound sensor.

7. Arrangement according to claim 5 or 6, characterized in that a plurality of sound sensors (6-11) are provided.

8. Arrangement according to one of claims 5 to 7, characterized in that the conveying path (1) is part of a continuous conveyor or a continuous conveyor system.

9. Arrangement according to one of claims 5 to 8, characterized in that the sound sensor (6-11) on a contact body (12) of the conveying path (1) or in the conveying path (1) incorporated contact body (16) is arranged.