WO2017089145A1

WO2017089145A1 - Determination of material properties by noise evaluation

Info

Publication number: WO2017089145A1
Application number: PCT/EP2016/077358
Authority: WO
Inventors: Andreas ROHRHOFER; Thomas Kuehas; Paul Fischer; Franz Hartl; Anna Mayrhofer
Original assignee: Primetals Technologies Austria GmbH
Priority date: 2015-11-24
Filing date: 2016-11-10
Publication date: 2017-06-01
Also published as: AT518043A1

Abstract

A lumpy material (1) is conveyed by means of a conveyor device (2) such that it comes into contact with a contact surface (7a, 7b) of the conveyor device (2) and moves in relation to the contact surface (7a, 7b). A noise (G) caused by the contact of the lumpy material (1) with the contact surface (7a, 7b) and the movement thereof in relation to the contact surface (7a, 7b) is detected by means of at least one sound sensor (6). The detected noise (G) is supplied to an evaluation device (8). The evaluation device (8) determines automatically at least one material property of the lumpy material (1) by evaluating the noise (G) detected during a time interval (T).

Description

description

Determination of material properties by sound evaluation

The present invention relates to a method for determining at least one material property of a particulate material.

The present invention further relates to an evaluation device for determining at least one material property of a lumpy material.

In production facilities such as a steelworks or a blast furnace often different materials (raw materials, additives, ...) are needed for production. These materials are often delivered in chunk form. The shape may vary as needed. For example, lime can be supplied in the form of small or larger pieces or chunks, aluminum in the form of chips, coke in larger chunks, etc. Other forms are - depending on the material and application - possible and conceivable.

The delivered materials are transported sorted according to type to corresponding storage bunkers in the respective production plant. For example, the respective material is emptied by a truck in a hopper, from which it is transported via conveyors such as conveyor belts and the like to the storage bunkers. If the corresponding material is needed later in a production step, it is removed from the bunker.

The quality of the delivered materials must comply with strict guidelines. For example, materials below a specified grain size must not enter a converter, since in this case they would be sucked off the converter exhaust due to their fine grain size and insufficient mass. If this were the case, then a steel quality other than the desired one would be produced and would continue to produce the suction and subsequent cleaning. supply device such as an electrostatic filter are excessively loaded. Furthermore, the accumulated dust would have to be disposed of again, which is also associated with costs. In the prior art, the delivery of materials and their promotion to the storage bunkers by the operating personnel of the production plant is monitored directly or indirectly via cameras. This approach is on the one hand staff-intensive and beyond due to the often high transport speed of the material is not accurate enough.

Another option is to take samples of the material and analyze the samples. This procedure only checks samples. Furthermore, the analysis is often associated with significant delays. If, for example, the analysis determines that it is the wrong material or a material that does not meet the specifications, this material has been stored in the corresponding storage bunker for a long time. Therefore, the error can not be corrected or only with considerable effort.

Another possibility is the acoustic evaluation. In this case, if the operator has the necessary experience, he or she will be able to identify the wrong material during transport to the storage bunker during the transport. For example, limestone in granular form and aluminum shavings differ significantly in volume and frequency range of the noise generated during transport. This is especially true at transfer points where the material from one conveyor element to another conveyor element

is handed over. For example, the impact of the material on a conveyor element or on a baffle causes a different sound depending on the material.

If, in the case of the acoustic evaluation by the operating staff, an incorrect material filling is detected, the further filling of the storage bunker is aborted. It may, however, be certain Take time for the wrong material to be detected and responded to.

Although acoustic detection offers great potential by design, it is rarely used in practice. On the one hand, appropriately experienced operating personnel are available only in the rarest of cases. Furthermore, to implement this procedure, an operator must always move to the vicinity of the respective transport route. In this place prevail both a strong dust load and a strong noise pollution.

Another disadvantage is the habituation factor of human hearing. As the mined material changes slowly and continuously, the differences are barely discerned by the human ear. The gradual transition from one

Good quality material to a poor quality material, unlike an abrupt transition, is therefore often misrecognized. Another possible source of error is the subjectivity of the operator's assessment of the material.

The object of the present invention is to provide possibilities by means of which in production facilities in a simple way, detection and determination of at least one material property of a material is possible.

The object is achieved by a method having the features of claim 1. Advantageous embodiments of the method are the subject of the dependent claims 2 to 24.

According to the invention, a method is provided for determining at least one material property of a lumpy material, wherein the lumpy material is conveyed by means of a conveying device such that it makes contact with a contact surface of the conveying device and is moved relative to the contact surface, wherein by means of at least one sound sensor is detected by the contact of the lumpy material with the contact surface and its movement relative to the contact surface noise generated,

- wherein the detected noise is supplied to an evaluation device,

- wherein the evaluation device automatically determines the material property by evaluating the detected during a time interval noise.

The sound sensor may be formed as needed. For example, the sound sensor may be a microphone, a hydrophone or a sensor for detecting structure-borne noise. The material property may alternatively be the type of material (that is, what material it is) and the structure of the material (that is, in what form the particular material is present). The contact surface may be an area that is present anyway on the conveyor. Alternatively, the contact surface may have been integrated into the conveyor device specifically for generating noise. In the latter case, it must of course be ensured that it does not hinder the transport of the lumpy material. The material can also be determined as needed. This applies both to the type of material and its structure. In particular, the material can be present, for example, in the form of larger or smaller chunks, in the form of larger or smaller grains (ie gravel or sand-like), in the form of chips or possibly even in the form of a powder.

In many cases, the lumpy material is transferred at a transfer point from a first conveying element of the conveyor to a second conveying element of the conveyor. In this case, the contact surface can be arranged in particular in the region of the transfer point. For example, it may be a guide plate or a funnel. It can also be a baffle plate arranged especially for generating noise in the region of the transfer point. But there are also other configurations possible. In many cases, the first conveying element is arranged stationary, so that the lumpy material is supplied to the first conveying element at a predefined feeding point and the transfer point, at which the lumpy material is transferred to the second conveying element, is also stationary. This makes it possible to detect and check all materials by means of a single sound sensor, which is located in the region of the transfer point. This applies both when the second conveying element is arranged stationary, so that the lumpy material is discharged from the second conveying element at a predefined discharge point, as well as in the case that the second conveying element is movable, so that the lumpy material of the second conveying element is supplied depending on the positioning of one of several storage areas.

The movement of the material relative to the contact surface may be - according to material and other circumstances - an orthogonal or oblique impact on the contact surface or a Ent long sliding along the contact surface.

Preferably, the sound sensor has a directional characteristic. As a result, it can be achieved that the sound sensor essentially only detects noises which originate from the region where the lumpy material moves on the contact surface.

Preferably, the noise detected during the time interval is first filtered by the evaluation device during the evaluation and then processed further. The filtering may be for example a filtering with a high pass, a low pass or a bandpass. alternative

or in addition, an amplitude limitation of the detected noise can take place.

In a particularly preferred embodiment, the evaluation device subtracts an ambient noise from the noise detected during the time interval. Dadur the evaluation accuracy can be increased. It is possible that the ambient noise is detected in real time by means of another sound sensor. Alternatively, it may be a stored ambient noise, which was previously detected by means of the sound sensor or the further sound sensor. If the ambient noise is previously detected by means of the sound sensor, by means of which also the noise to be evaluated is detected, the ambient noise is detected during a period during which no lumpy material is moved in the detection range of the sound sensor.

In a preferred embodiment of the present invention, it is provided that of the evaluation device for determining the material property

a resulting function is determined as a linear combination of predefined output functions, wherein the output functions weighted with a respective weighting factor enter into the resulting function,

the weighting factors are determined in such a way that a norm of the deviation of the resulting function from a spectrum of the sound detected during the time interval as an integral over the frequency is minimal,

for the respective material property, a respective set of reference weighting factors is given, by which a respective reference function is determined, and

- The material property is determined based on a comparison of the resulting function with the reference functions or on the basis of a comparison of the determined weighting factors with the reference weighting factors of the respective reference function.

This procedure may be useful, in particular, if the material property is a type of material, that is to say characterized by which material it is (for example, coke, pig iron, scrap, lime, aluminum, etc.).

The spectrum may be, for example, a power spectrum of the noise. The term "norm" is a standard in the meaningful meaning, ie a value which is dependent on the amount of the difference of the deviation of the resulting function of said spectrum. Generally in the context of the present invention, therefore, the value

where g is the resulting function, S is the spectrum and f is the frequency.

For example, the standard may be the well-known Euclidean norm.

As already mentioned, it is possible to determine the material property on the basis of a comparison of the determined weighting factors with the reference weighting factors of the respective reference function. However, if, alternatively, the material property is determined on the basis of a comparison of the resulting function with the reference functions, it is possible in particular for the standard of the deviation of the resulting function from the respective reference function to be determined by the evaluation device for determining the material property at a number of nodes the number of

Support points is less than the number of output functions that enter into the linear combination. This procedure often leads to good results with very little computational effort.

The output functions can be determined as needed.

For example, these may be polynomial functions.

Furthermore, it is possible that the output functions are orthogonal functions. In particular, the use of orthogonal functions as output functions offers the advantage that it is possible to independently determine the weighting factors for the individual output functions. In particular, the combination of these two types of functions, ie the use of orthogonal polynomials, offers the advantage of initially determining only the weighting factors for polynomials of relatively low degree and then gradually determining the weighting factors for higher order polynomials as needed, without the already determined weighting factors to determine again. As a result, the spectrum can be gradually brought closer to the spectrum by the resulting function with little computation effort until the resulting function approximates the spectrum sufficiently well.

Orthogonal functions are well known to those skilled in the art. By way of example, the well-known Chebyshev polynomials and the also generally known Legendre polynomials may be mentioned. If necessary, in the context of the present invention, a frequency range within which the integral is formed can be mapped to the range of -1 to +1, in particular linearly mapped.

As far explained so far, the method is executed by the evaluation device in a working mode. It is possible that this is the only mode of operation assumed by the evaluation device. Alternatively, it is possible for the evaluation device to additionally operate in a learning mode. Also in the learning mode, the particulate material is conveyed such that it contacts the contact surface and is moved relative to the contact surface. In contrast to the working mode, however, the material property of the evaluation device is specified in the learning mode. Furthermore, the evaluation device repeatedly uses the learning mode in the learning mode

detected by the at least one sound sensor during a respective time interval caused by the contact of the lumpy material with the contact surface and its movement relative to the contact surface noise,

a respective resulting function is determined as a linear combination of the given output functions for the respective time interval, the output functions being determined by a respective weighting factor weighted enter into the resulting function, and

- Determined for the respective time interval, the weighting factors such that a norm of the deviation of the respective resulting function of a spectrum of the detected during the respective time interval noise is minimal.

The reference weighting factors are then determined by the evaluation device in the learning mode on the basis of the totality of the weighting factors respectively determined for the time intervals and assigned to the predetermined material property. In the learning mode, the evaluation device is thus able to learn the characteristic noise of a new material property analogously to the later recognition of a material property similar to a teach-in.

In the learning mode, at the same time, a permissible tolerance range can also be determined within which a material is recognized later in the working mode despite deviations of the weighting factors from the reference weighting factors or the resulting function from the corresponding reference function. The tolerance range can be determined, for example, based on variances determined in the learning mode. For example, the variances may be related to one of the reference weighting factors or to a support point.

The time interval during which the noise is detected may be in particular in the one or two-digit seconds range. In tests, periods of about 1 second to about 30 seconds have proven to be advantageous.

It is possible that the time interval is predetermined. Alternatively, it is possible that a sound energy of the detected noise is determined by the evaluation device from the beginning of the time interval and the time interval is terminated by the evaluation device when the accumulated sound energy reaches an energy limit. The last This approach leads in particular to an increased reliability in the recognition of a material property.

As part of an alternative preferred embodiment, it is provided that the evaluation device

subdividing the time interval into a plurality of subintervals,

- For the sub-intervals each determined a proportion to which the power of a power spectrum of the detected during each sub-interval noise between a lower limit frequency and one above the lower

Limit frequency lying upper limit frequency is, and

- the material property is determined on the basis of the proportion of subintervals in which the share of the power is above a predetermined threshold value.

This procedure can be useful, in particular, if the material property is a structure, that is, it characterizes whether the respective material is coarse-grained, fine-grained, powdered, in chips and the like. The recognition of a material structure usually requires that the material type is already known. For example, the upper and / or lower limit frequency and / or the threshold value may be determined depending on the type of material. In some cases, the recognition of a material structure is also possible if the material type is not known.

In particular, on the basis of the proportion of subintervals in which the proportion of the power is above the threshold value, for example, a certain degree of granularity can be determined. It can be deduced, for example, that it is a "good" material if the number is above the threshold, or it is a "bad" material if the number is below the threshold. It is also possible to compare with multiple thresholds. For example, a material may be judged to be good if the number is above a first threshold and poor if the number is below a second threshold Threshold is. If the number is between the two thresholds, a warning message can be issued to the operator as a more accurate check is required.

In experiments, it has proved to be advantageous that the lower cutoff frequency is between 200 Hz and 1000 Hz, for example at about 500 Hz. It has also proven to be advantageous that the upper cutoff frequency is between 500 Hz and 2000 Hz, for example at approx. 1000 Hz. Irrespective of the specific choice of the two cutoff frequencies, however, the higher-order condition always applies that the lower cutoff frequency is smaller than the upper cutoff frequency.

In experiments, it has also proven to be advantageous if the subintervals have a maximum duration of 1 second. In many cases, it is even advantageous if the duration of the subintervals is at most 100 ms, in particular between 20 ms and 80 ms, for example at about 50 ms. The time interval should preferably correspond to 20 to 100 subintervals.

In a further preferred embodiment, it is provided that the evaluation device determines the material property by means of fuzzy logic on the basis of the proportion of subintervals in which the proportion of the power lies above the predetermined threshold value.

Preferably, it is at least optionally possible for the evaluation device to specify a trigger signal by an operator and for the predetermining of the trigger signal to determine the start of a time interval. This makes it possible for the operator to specifically request a review of the material property, if necessary. For example, an operator may have become suspicious due to a "somehow" altered sound and would now like to have checked whether subsidized material is still proper. It is possible that the evaluation device works independently, that is without further specification of data. Preferably, however, the evaluation device is given data relating to the particulate material. In this case, it is possible that the evaluation device takes into account the data in the context of the evaluation of the detected noise.

For example, an operator or the automation system of the evaluation device can specify information about the conveying speed with which the lumpy material is transported. In this case, it is possible, for example, for the evaluation device to adapt the evaluation as such based on the conveying speed.

For example, the reference weighting factors can be adjusted to determine the type of material. It is also possible, for the determination of the material structure, to adapt the lower and / or the upper limit frequency or to vary the threshold value. It is also possible that the evaluation device information about the beginning and end of the transport of the lumpy material are specified. In this case, the evaluation device may, for example, start and stop the operation in dependence on this information. Also, a plausibility check is possible if the evaluation device detects any noise caused by the contact of the particulate material with the contact surface and its movement relative to the contact surface. Furthermore, it is possible for the evaluation device to specify which material is conveyed. In this case, the evaluation device can perform a plausibility check as to whether the material property of the recognized material corresponds to an expected material property. It is also possible that the evaluation device adapts the order in which certain tests are carried out - for example the comparisons of the resulting function with the reference functions - on the basis of the data. Preferably, the evaluation device outputs an information representing the determined material property and / or stores this information in the sense of a history. In particular, in the case of storage as a history of the recognized material property is also retrievable later, for example, as a guarantee voucher, as proof of a proper or faulty material or for a subsequent search of errors.

Preferably, the evaluation device compares the determined material property with an expected material property. In the case of a deviation of the determined material property from the expected material property, the evaluation device issues an alarm message. The alarm message, if issued in addition to the detected material property message, is a different message than the default material property recognition message as such. The expected material property can be known to the evaluation device, for example, as already mentioned, by a specification from the automation device. Alternatively, the material property can be preset or the evaluation device can be specified by an operator. The output of the alarm message can be made to the operator and / or to the automation device of the conveyor. In the latter case, the alarm message can cause an automatic stop of the further transport of the lumpy material.

Preferably, a noise is detected by means of a plurality of sound sensors at different locations. In this case, the detected sounds - that is, the sounds detected by the plurality of sound sensors - are supplied to the evaluation device. As a result, the evaluation device is able to determine on the basis of the detected noise, at which location the sound caused by the contact of the particulate material with the contact surface and its movement relative to the contact surface is detected by the sound sensor arranged there. In particular, the evaluation device can thereby Verify that this location matches an expected location. In the case of disagreement, the evaluation device can issue an alarm message. The output of the alarm message can - as before - done to the operator and / or to the automation device of the conveyor. In the latter case, the alarm message can cause an automatic stop of the further transport of the lumpy material. The locations can be arranged one behind the other along the transport path of the material. In this case, it is possible, for example, automatically detect a blockage of a transport path. Alternatively or additionally, the locations may be arranged parallel to each other, so that therefore only at a single one of the locations can be detected by the contact of the particulate material with the contact surface and its movement relative to the contact surface caused noise. In this case, it can be checked in particular whether the lumpy material is supplied to the correct storage bunker or other depot or, generally speaking, is on the right transport path.

The object is further achieved by an evaluation device for determining at least one material property of a lumpy material. This evaluation device has a first input for supplying a detected sound. The lumpy material is conveyed by means of a conveyor such that it contacts a contact surface of the conveyor and is moved relative to the contact surface. The at least one sound sensor detects the noise caused by the contact of the particulate material with the contact surface and its movement relative to the contact surface. The noise detected by the sound sensor is supplied to the first input of the evaluation device. A processing device of the evaluation device automatically evaluates the detected sounds during a time interval and determines the material property.

The device ensures that a reliable recognition of the material properties takes place. A preferred embodiment of the evaluation device has a filter for filtering the noise, and / or an amplitude limiter for limiting the amplitude of the noise (G).

The filter is preferably a high-pass, low-pass or bandpass filter.

Preferably, the evaluation device has a second input for supplying an ambient noise, and a subtractor for subtracting the ambient noise from the noise. This allows a more accurate determination of the material properties, since noise that is not caused by the contact of the particulate material with the contact surface and its movement relative to the contact surface, are not supplied to the processing device.

An advantageous embodiment of the evaluation device provides that the processing device implements a method according to one of claims 7 to 23.

The advantageous embodiments of the evaluation device and the processing device correspond to those of the method. Reference is therefore made to the above statements.

The above-described characteristics, features and advantages of this invention, as well as the manner in which they are achieved, will become clearer and more clearly understood in connection with the following description of the embodiments, which will be described in more detail in conjunction with the drawings. Here are shown in a schematic representation:

1 shows a conveyor and parts of a production plant,

2 to 4 possible embodiments of a contact area,

5 shows an evaluation device,

6 shows a time course of a sound and an associated spectrum,

7 shows a flow chart,

8 to 10 curves of possible reference functions, 11 shows a possible reference function with an error band,

12 shows a possible reference function with an error band at interpolation points,

FIGS. 13 and 14 are flowcharts;

FIG. 15 ei

egg

FIG. 16 ei

FIG. 17 ei

FIG. 18 ei

1,

FIG. 19 ei

FIG. 20 ei

1, a lumpy material 1 is conveyed by means of a conveyor 2. The conveying device 2 may comprise, for example, a number of conveying elements 3a to 3c for conveying the particulate material 1, in particular conveyor belts. The conveyor 2 may, for example, as shown in FIG 1, a front conveyor element 3a, a central conveyor element 3b and a rear conveyor element 3c include. For example, it is possible according to the representation in FIG. 1 that lumpy material 1 is initially applied to the front conveying element 3 a during delivery. For example, the lumpy material 1 can be applied by means of a truck 4 directly or via a hopper, not shown, on the front conveyor element 3a. The lumpy material 1 can be conveyed by means of the front conveyor element 3a to a front transfer point 4a and applied there to the central conveyor element 3b. In an analogous manner, the lumpy material 1 can be conveyed by means of the middle conveying element 3b to a central transfer point 4b and applied there to the rear conveying element 3c. By means of the rear conveying element 3c, the lumpy material 1 is then conveyed to one of a plurality of rear transfer points 4c and fed from there to a respective storage area 5a to 5d. The transport of the lumpy material 1 of the third crossing points 4c can be done for example via slides 5 '. The lumpy material 1 has material properties. A material property is, for example, the type of the respective material 1, that is, whether it is, for example, coke, iron ore, lime, aluminum or another material. Another material property is, for example, the structure of the respective material 1, that is to say, for example, chunks, fine-grained material, chips and the like. Such material properties should be able to be determined automatically.

To determine at least one material property of the lumpy material 1, a noise G is detected by means of at least one sound sensor 6. The sound sensor 6 is arranged in a region and - if necessary - aligned such that the noise G is detected, which by the contact of the lumpy material 1 with a contact surface 7 a, 7 b and the movement of the lumpy material 1 relative to the contact surface 7 a, 7b (see FIG. 2 to 4 in detail) is caused.

In particular, the lumpy material 1 is conveyed by means of the conveying device 2 or the conveying elements 3 a to 3 c in such a way that it makes contact with said contact surface 7 a, 7 b and is moved relative to the contact surface 7 a, 7 b. For example, as shown in FIGS. 2 and 3, a baffle surface 7a may be provided as the contact surface 7a, 7b. In this case, the lumpy material 1 by means of one of the conveying elements 3a to 3c - shown in Figures 2 and 3 purely by way of example the front conveying element 3a - are promoted such that it impinges on the baffle surface 7a. The impact can be carried out in accordance with the illustration in FIG. 2 substantially orthogonally to the baffle surface 7a or as shown in FIG. 3 at an angle different from 90 ° relative to the baffle surface 7a (ie obliquely to the baffle surface 7a). Alternatively, it is possible, for example, according to the representation in FIG. 4, that the contact surface 7a, 7b as

Sliding surface 7b is formed, which slides the particulate material 1 along or slides. In each of these cases it is possible to detect the resulting noise G by means of the sound sensor 6.

The location where the noise G is detected by the sound sensor 6 may be determined as needed. According to the above explanations, it is possible in particular that the contact surface 7a, 7b is arranged in the region of one of the transfer points 4a to 4c and that the noise G is detected at this point. Furthermore, it is particularly possible that the transport element 3a, 3b arranged upstream in the transport path is arranged in a stationary manner. The upstream conveying element 3a, 3b is that conveying element 3a, 3b, from which the lumpy material 1 is discharged at the transfer point 4a, 4b. In this case, the lumpy material 1 is fed to the upstream conveying element 3a, 3b as shown in FIG. 1 at a predefined supply point. Furthermore, in this case, as shown in Figure 1, the transfer point 4a, 4b, where the lumpy material 1 is transferred to the downstream conveying element 3b, 3c, stationary. The downstream conveying element 3b, 3c is that conveying element 3b, 3c, from which the lumpy material 1 at the transfer point 4a, 4b is taken.

It is possible that the downstream conveying element 3b, 3c is also arranged stationary. In this case, the lumpy material 1 is discharged from the downstream conveying element 3b, 3c at a predefined delivery point. In the illustration of FIG. 1, this is the case, for example, in the case of the middle conveying element 3b. Alternatively, it is possible for the downstream conveying element 3b, 3c to be movable, so that the lumpy material 1 is fed from the downstream conveying element 3b, 3c, depending on its positioning, to one of a plurality of storage areas 5a, 5d. In the illustration of FIG. 1, this is the case, for example, in the case of the rear conveying element 3c. The rear conveying element 3c can be displaced, for example, in the direction of the double arrow shown, as shown in FIG. Furthermore, the conveying direction of the rear conveyor element 3 c as needed to the left or to be right. As a result, each of the four storage areas 5a to 5d can be operated by means of the conveying element 3c. Alternatively and possibly even in addition to a displaceability, the rear conveying element 3c could also be pivotable.

The noise G detected by the sound sensor 6 is fed to an evaluation device 8 according to FIG. The evaluation device 8 automatically determines the sought material property by evaluating the detected noise G. For this purpose, the detected and the evaluation device 8 supplied noise G is amplified as shown in FIG 5 usually first in an amplifier 9, then digitized in an analog-to-digital converter 10 and filtered in a filter 11. Only then is the signal G processed further. Furthermore, according to the representation in FIG. 5, the evaluation device 8 can subtract an ambient noise GU from the detected noise G. The ambient noise GU can be detected, for example, according to the representation in FIG. 5 by means of a further sound sensor 12. The sound sensor 12 must of course be arranged for this purpose so that it does not detect the noise G or only to a very small extent.

The filtering in the filter 11 may be high-pass filtering, low-pass filtering, band-pass filtering, or other filtering, such as one, as needed

Amplitude limiting. Under certain circumstances, the subtraction of the ambient noise GU may be part of the filtering. Alternatively, the subtraction of the ambient noise GU, as shown in FIG. 5, may be an independent processing step.

The previously described processing of the noise G are pre-processing, which are upstream of the actual evaluation of the noise G. Mandatory, none of these measures is required. However, the analog-to-digital conversion is usually present. The other measures are conducive to the evaluation of the noise G. Furthermore, below is always from the evaluation of the noise G spoken. This evaluation is based on the noise as it is fed to a processing device 13 of the evaluation device 8. So even if below is always "only" spoken of the noise G, it may be the filtered noise, from which, if necessary, the ambient noise GU is already subtracted.

Hereinafter - starting with FIG. 6 - in connection with FIGS. 6 to 14, first of all possible procedures will be explained, which are advantageous if the material property is a type of material. In principle, however, the procedures according to FIGS. 6 to 14 are not limited to determining a type of material. Then, starting with FIG. 15, in conjunction with FIGS. 15 to 17, possible procedures are explained, which are advantageous if the material property is a material structure. In principle, however, the procedures according to FIGS. 15 to 17 are not limited to the determination of a material structure.

According to FIGS. 6 and 7, the top representation and the step S 1 in FIG. 7 are selected from the detected noise G by a time interval T, ie a temporally limited range of the noise G detected as a function of the time t Length of the time interval T can be in the single-digit second range, for example between 1 s and 5 s. The length of the time interval T can also be greater. In particular, the length of the time interval T can also be in the two-digit second range, for example between 10 s and 30 s. For the range is - see in Figure 6, the lower view - a corresponding frequency spectrum determined. Thus, the spectrum S (of course as a function of the frequency f) is determined. For example, a Fourier transformation, in particular a fast Fourier transformation (FFT), may be carried out in accordance with step S in FIG. 7 to determine the spectrum S. The spectrum S may in particular be a power spectrum of the detected noise G. Then, a resulting function g is determined by the evaluation device 8 in a step S2. The resulting function g is a linear combination of given output functions gi (i = 0, ..., N). According to FIG. 7, the output functions gi enter the resulting function g with a respective weighting factor ai. The weighting factors ai are determined in a manner known per se such that a norm of the deviation of the resulting function g from the spectrum S as an integral over the frequency f is minimal. The integral extends from a minimum frequency fmin to a maximum frequency fmax. The minimum frequency fmin and the maximum frequency fmax are selected such that the entire relevant spectrum S is covered. For example, the minimum frequency fmin can be at 0 Hz and the maximum frequency fmax can be in the two-digit kilohertz range.

The number of determined weighting factors ai (ie the value N + 1) can be determined as needed. In general, the value N has a significant size. For example, the value N may be 20 or more, more preferably 30 or more. In tests, values N between 40 and 60, in particular between 45 and 55, have proven to be advantageous.

The evaluation device 8 is shown in FIG 5 for certain material properties, a respective set of Referenzwich- factors ail, ai2, ai3 given. The respective set of reference weighting factors ail, ai2, ai3 determines according to FIGS. 8 to 10 a respective reference function gR1, gR2, gR3. The number of material properties, associated sets of reference weighting factors ail, ai2, ai3 and associated reference functions gR1, gR2, gR3 can be determined as required. The given according to FIG 5 number of three sets of reference weighting factors ail, ai2, ai3, etc. is purely exemplary. The reference functions gR1, gR2, gR3 shown in FIGS. 8 to 10 are purely exemplary as such. It is essential and easily recognizable, however, that the reference functions gR1, gR2, gR3 are clearly different. In a step S3, the evaluation device 8 compares the determined resulting function g with the reference functions gR1, gR2, gR3 and determines therefrom (positive case) the material property. The determined material property (or a corresponding information I) outputs the evaluation device 8 in a step S4. If (in the negative case) no agreement could be determined within the framework of the comparison, a message is issued in a step S5 that the material property could not be determined. In both cases, the output can be made, for example, to an operator 14 or to an automation system 15 for the conveyor 2. A combined output to the operator 14 and to the automation system 15 is possible.

It is possible that the evaluation device 8 compares the determined weighting factors ai first with the reference weighting factors ail of the reference function gRl, then with the reference weighting factors ai2, the reference function gR2 and then with the reference weighting factors ai3 of the reference function gR3 and so on. Alternatively, it is possible for the evaluation device 8 to compare the functions g, gR1, gR2, gR3 as such within the scope of the aforementioned comparison. Which of these two approaches leads to better results is a matter of individual case. For example, as shown in FIG. 11 for one of the reference functions gR1, gR2, gR3 (namely, the reference function gR1), it is possible to define an error band and to check whether the resulting function g lies within the respective error band. As required, the error band can be determined uniformly for all reference functions gR1, gR2, gR3 or individually for the respective reference function gR1, gR2, gR3. To check whether the resulting function g is within the respective error band, a number of nodes 16 are preferably defined as shown in FIG 12. The number of nodes 16 is smaller than that Number of output functions gi, which enter into the linear combination. If M denotes the number of nodes 16, then M <N + 1. The term "number of output functions" in this context does not necessarily mean the number of output functions gi whose respective weighting factor ai has a value different from 0. What is meant is the number of weighting factors that are determined at all (even if Their value may be 0 in individual cases.) In the case of the embodiment according to FIG 12, therefore, the norm of the deviation of the resulting function g from the respective reference function gR1, gR2, gR3 is determined only for the support points 16. The number of four shown in FIG Support points 16 is only a pure example.

The output functions gi can be polynomial functions

In this case, every output function gi is given by gi (f) = biO + bil - f + bi2 - f ² + .Mi ^■ where bii Φ is 0. In the simplest case applies to the output functions gi

(f) = f (3)

Preferably, the output functions gi are orthogonal functions. If the initial positions gi are orthogonal functions, they satisfy the condition

where gj 1 and gj2 are each one of the output functions gi and 5ij the so-called Kronecker delta. So we have 5ij = 1 for i = j and 5ij = 0 for i Φ j. The output functions gi can be determined recursively in this case, where

* 0 (/) = -7 -! === (5) jj max- / min The definition of the output functions gi as orthogonal polynomials offers, in particular, the advantage that the individual weighting factors ai can be determined one by one and it can be checked in each case whether the deviation of the resulting function g from the spectrum S as an integral over the frequency f is sufficiently small , If this is the case, the further determination of weighting factors ai can be aborted, and the not yet determined weighting factors ai can be set to the value 0. If this is not the case, further weighting factors ai can be determined without having to redetermine the previously determined weighting factors ai.

As far explained so far, the method for determining the material property is carried out by the evaluation device 8 in a working mode. In working mode, the respective material property is determined on the basis of the detected noise G. However, similar to a teach-in, it is possible to teach the evaluation device 8 new material properties in a similar manner. This will be explained in more detail below in conjunction with FIG.

According to FIG. 13, the evaluation device 8 checks in a step S11 whether it is in a learning mode. If this is not the case, the evaluation device 8 is in working mode. In this case, the evaluation device 8 proceeds to a step S12. Step S12 corresponds to the procedure of FIG. 7 as a whole.

In the learning mode, the evaluation device 8 first proceeds to a step S13. In step S13, the evaluation device is given the material property as such. Furthermore, the particulate material 1 is conveyed such that it contacts the contact surface 7a, 7b and is moved relative to the contact surface 7a, 7b. This step is not shown in FIG. 13 because it is not executed by the evaluation device 8. The conveying of the lumpy material 1 takes place in the same manner as in the working mode. In a step S14, the evaluation device 8 sets a counter 17 (see FIG. 5) to the value m = 1. In a step S15, the evaluation device 8 extracts a time interval T from the detected noise G and determines a corresponding frequency spectrum. The step S15 corresponds to the steps Sl and S2 of FIG 7. It is therefore made to the above statements. In a step S16, the evaluation device 8 stores the weighting factors ai determined as part of the step S15.

In a step S16, the evaluation device 8 checks whether the value of the counter 17 has already reached a final value M. If this is not the case, the evaluation device 8 proceeds to a step S17. In step S17, the increment

Evaluation device 8 the counter 17. Then, it returns to step S15. The steps S15 to S17 are thus executed several times by the evaluation device 8 in the learning mode. On the other hand, when the counter 17 has reached the final value M, the evaluation device 8 proceeds to a step S18. In step S18, the evaluation device 8 evaluates the weighting factors ai determined as part of the multiple execution of step S15 in their entirety. For example, the evaluation device 8 can determine the respective mean value of the respective weighting factor ai, that is to say, for example, the mean value of the weighting factors a1, which are determined in run 1, in run 2, and so on until run M of the loop of FIG. If, for example, the preference weighting factors ail, ai2, ai3 are already known for three material properties and the reference weighting factors ai4 for a fourth material property are to be determined in the course of the procedure in FIG. 13, the reference weighting factor al4 can be used as al4 (eg 6)

be determined. The letter m in equation 6 stands for the respective iteration, ie the respective passage of the loop of FIG.

Analogous determinations are made for the weighting factors a2, a3 and so on. As a result, the reference weighting factors ai4 are thus determined by the evaluation device 8 in the learning mode on the basis of the totality of the weighting factors ai respectively determined for the time intervals T. The newly determined reference weighting factors ai4 are then assigned in a step S19 to the material property predetermined in step S13. As a result, it is possible to recognize the new, fourth material property from this time in the working mode, if corresponding matches.

Often, a step S20 is additionally present. In step S20, an allowable error band is determined for the new reference function gR4 defined by the newly determined reference weighting factors ai4. For example, variances can be determined in accordance with customary statistical procedures and, based on this, the permissible error band can be determined.

As far explained so far, the time interval T is predetermined. It therefore has a fixed, previously known length in the context of the procedures explained so far. Alternatively, it is possible to modify the procedure of step Sl of FIG. 7 as explained below in conjunction with FIG.

According to FIG. 14, the step S1 is replaced by steps S31 to S36. In step S31, an energy value E is set to 0. In step S32, the noise G detected by the sound sensor 6 is received for a (short) period of time. In step S33, the noise G received in step S32 is added to the previously received noise G, that is, timed thereto. In step S34, the energy content δΕ of the noise SG received in step S32 is determined. In step S35, the energy value E is incremented by the energy content δΕ. in the Step S36 checks the evaluation device 8, whether the energy value E has exceeded a limit E0. If this is not the case, the evaluation device 8 returns to step S32. Otherwise, the evaluation device 8 goes to step S2 (see also FIG. 7).

In the context of the procedure of FIG. 14, therefore, a sound energy E of the detected noise G is determined by the evaluation device 8 from the beginning of the time interval T. The time interval T is terminated by the evaluation device 8 when the accumulated sound energy E reaches an energy limit E0.

As an alternative to the procedures according to FIGS 6 to 14, it is possible for the evaluation device 8 - see the top illustration and the step S41 in FIG 16 - to subdivide the time interval T into a plurality of subintervals Ί "- the number of subintervals Ί "can be between 20 and 100 in particular. The duration of the subintervals Ί "is usually a maximum of 1 second, often up to 100 ms, in particular between 20 ms and 80 ms, for example about 50 ms.

FIG. 17 shows, purely by way of example, one of the subintervals Ί "of its power spectrum S. In a step S43, the evaluation device 8 determines the respective intervals in the respective intervals for the subintervals Ί" Power spectrum S contained energy P. Furthermore, the evaluation device 8 determined in a step S44 for the subintervals Ί "each a share of energy P '. The energy component P 'is that part of the energy of the respective power spectrum S, which is between a lower limit frequency fl and upper limit frequency f2. The lower limit frequency fl may for example be between 200 Hz and 1000 Hz, in particular at about 500 Hz. The upper limit frequency f2 may for example be between 500 Hz and 2000 Hz, in particular at about 1000 Hz. It is possible that the two limit frequencies fl, f2 of the evaluation device 8 are fixed. Alternatively, they can be specified to the evaluation device 8, for example by the operator 14.

In a step S45, the evaluation device 8 determines a proportion q = P '/ P for the subintervals Ί ".Figure 15 shows in the lower part purely by way of example a possible sequence of the determined proportions q. In a step S46, the evaluation device 8 finally determines the material property The determination takes place, in particular, on the basis of the proportion of subintervals T 'in which the proportion q is above a predetermined threshold value qO The threshold value q0 can be between 0.2 and 0.5, depending on the specification of the two limit frequencies f1, f2 If the total number of subintervals Ί "is known in advance, the number of subintervals Ί" can be used directly, otherwise the quotient with the total number of subintervals Ί "is usually formed beforehand. The evaluation device 8 may have a fuzzy logic 18 for the evaluation of the proportion of subintervals T ', in which the proportion q is above the predetermined threshold value qO, in particular as shown in FIGS.

It is possible that the evaluation device 8 permanently executes one or more of the methods explained above. Alternatively, it is possible that the evaluation device 8 executes (at least) one of these methods only from time to time. For example, it is possible for the evaluation device 8 to be given a triggering signal C by the operator 14 as shown in FIG. In this case, the specification of the trigger signal C may determine the beginning of a time interval T. By way of example, the evaluation device 8 can start a time interval T when the triggering signal C is given immediately or after a certain delay time. It is also possible that the evaluation device 8 from the automation system 15 - similar to a tracking - information I 'on the conveying of the lumpy material 1 are given and that the evaluation device 8 the inventive method in response to this information I 'begins and ends.

Furthermore, it is possible for the evaluation device 8 to specify data D related to the lumpy material 1. By way of example, in addition to the information I ', the data D may include information about the conveying path of the lumpy material 1, about a conveying speed and / or the type and structure of the lumpy material 1. In this case, it is possible for the evaluation device 8 to take into account the data in the context of the evaluation of the detected noise G. The specification of the data D can be done by the operator 14 or the automation system 15. For example, the evaluation device 8 in the event that it is given a conveying speed of the lumpy material, adjust the evaluation as such. In particular, for the determination of the material type, the reference weighting factors ail, ai2, ai3 or the size of the

Error band and / or for the determination of the material structure, the lower and / or the upper limit frequency fl, f2 and possibly also the threshold qO be adjusted. Also, a plausibility check is possible if the evaluation device 8 detects, for example, no noise G, which is caused by the contact of the particulate material 1 with the contact surface 7a, 7b and its movement relative to the contact surface 7a, 7b, although this is due to the data D of Case would have to be.

From the evaluation device 8, as already mentioned, according to FIG. 5, information I about the determined material property is output. The output can be made as needed to the operator 14 and / or to the automation system 15. When the output is made to the automation system 15, the automation system 15 is able to automatically process the determined material property. In particular, the automation system 15 (which, of course, knows which material is to be transported from where to where at what time) can check whether the detected material property is correct. If necessary, even existing funding can be slowed, stopped or interrupted. Alternatively or additionally, it is possible that the evaluation device 8 stores the determined material property in the sense of a history. The stored material property thus does not overwrite previously stored material properties, but is stored in addition to these, ideally together with a time stamp.

It is also possible that the evaluation device 8 an expected material property is known. For example, corresponding specifications can be made by the operator 14 and / or the automation system 15. In the case of such specifications, the evaluation device 8 can compare the determined material property with the expected material property. In the case of a deviation of the determined material property from the expected material property, the evaluation device 8 according to FIG. 5 gives a

Alarm message A off. The output of the alarm message A preferably takes place to the operator 14, but can also be transmitted to the automation system 15 in addition. The alarm message A is a message different from the information I '. It may be, for example, an audible and / or visual alarm.

In the minimum case, only a single sound sensor 6 is present. Preferably, however, according to the illustration in FIG. 18, in each case a noise G is detected by means of a plurality of sound sensors 6 at different locations. The detected noises G are fed to the evaluation device 8 according to FIG. In this case it can be determined by the evaluation device 8 on the basis of the detected noise G, at which location by the sound sensor 6 arranged there by the contact of the lumpy material 1 with the (local) contact surface 7a, 7b and its movement relative to the (there ) Contact surface 7a, 7b caused noise G is detected. On the one hand, the evaluation device 8 can then only evaluate this one noise G. On the other hand, the evaluation device 8 Verify that this location matches an expected location. In the case of disagreement, the evaluation device 8, in particular according to the illustration in FIG 5 output an alarm message A '.

The used in the context of the present invention

Sound sensors 6 may be formed as needed. For example, it may be a microphone, a hydrophone or a structure-borne sound sensor. In particular, in the case of a microphone and possibly also in the case of a hydrophone, the sound sensor 6 may in particular have a directional characteristic. This will be explained in more detail below in connection with FIGS. 19 and 20.

According to FIG. 19, the sound sensor 6 has a preferred direction 19. If the sound from the preferred direction 19 impinges on the sound sensor 6, the sound sensor 6 according to FIG. 20 has a maximum sensitivity. The greater an angle α at which the sound impinges on the sound sensor 6, deviates from the preferred direction 19, the lower becomes the sensitivity according to FIG. A relative sensitivity normalized to the maximum sensitivity therefore decreases to values below 1. Directional characteristic now means that the angle αθ, at which the relative sensitivity drops below the value of 0.1, is at a maximum of 20 °.

In summary, the present invention thus relates to the following facts:

A lumpy material 1 is conveyed by means of a conveyor 2 such that it contacts a contact surface 7a, 7b of the conveyor 2 and is moved relative to the contact surface 7a, 7b. By means of at least one sound sensor 6, a sound G caused by the contact of the lumpy material 1 with the contact surface 7a, 7b and its movement relative to the contact surface 7a, 7b is detected. The detected noise G is fed to an evaluation device 8. The evaluation device 8 determines by evaluating the during a Time interval T detected noise G automatically at least one material property of the particulate material. 1

The present invention has many advantages. In particular, a reliable detection of material properties is possible at any time in a simple and cost-effective manner. The operating personnel are relieved of noise and dust. Due to the coupling with the automation system 15, it is also possible to implement mutual automatic adjustments between the evaluation device 8 and the automation system 15.

Although the invention has been further illustrated and described in detail by the preferred embodiment, the invention is not limited by the disclosed examples, and other variations can be derived therefrom by those skilled in the art without departing from the scope of the invention.

LIST OF REFERENCE NUMBERS

1 piece of material

2 conveyor

3a to 3c conveying elements

4a to 4c transfer points

5a to 5d storage areas

5 'slides

6 sound sensors

7a, 7b contact surfaces

8 evaluation device 9 amplifiers

10 analog-to-digital converter 11 filters

12 further sound sensor 13 processing device 14 operator

15 Automation System 16 Interfaces

17 counters

18 fuzzy logic

19 preferred direction

A, A 'Alarm messages

ai weighting factors ail, ai2, ai3 reference weighting factors

C trip signal

D data

f frequency

f1, f2 cutoff frequencies

E energy value

E0 limit

G noise

g resulting function gi output functions gRl, gR2, gR3 reference function

GU ambient noise

I, I 'information

Value of the counter M final value

P energy

P 'energy share q share q0 threshold

S spectrum

Sl to S46 steps

T time interval

T 'partial intervals t time

Oi, αθ angle δΕ energy content

Claims

claims

1. A method for determining at least one material property of a lumpy material (1),

- wherein the particulate material (1) by means of a conveyor (2) is conveyed such that it contacts a contact surface (7a, 7b) of the conveyor (2) and relative to the contact surface (7a, 7b) is moved,

wherein by means of at least one sound sensor (6) by the contact of the lumpy material (1) with the contact surface (7a,

7b) and whose movement relative to the contact surface (7a, 7b) caused noise (G) is detected,

- wherein the detected noise (G) is fed to an evaluation device (8),

- wherein the evaluation device (8) by evaluating the detected during a time interval (T) noise (G) automatically determines the material property.

2. The method according to claim 1,

characterized ,

in that the lumpy material (1) is transferred at a transfer point (4a, 4b) from a first conveying element (3a, 3b) of the conveying device (2) to a second conveying element (3b, 3c) of the conveying device (2) and that the contact surface ( 7a, 7b) in the region of the transfer point (4a, 4b) is arranged.

3. The method according to claim 2,

characterized ,

in that the first conveying element (3a, 3b) is arranged stationary so that the lumpy material (1) is fed to the first conveying element (3a, 3b) at a predefined feeding point and the transfer point (4a, 4b) at which the lumpy material (FIG. 1) is transferred to the second conveying element (3b, 3c), is also stationary.

4. The method according to claim 2 or 3,

characterized ,

that the second conveying element (3b) is arranged stationary, so in that the lumpy material (1) is delivered from the second conveying element (3b) at a predefined delivery point or in that the second conveying element (3c) is movable so that the lumpy material (1) moves from the second conveying element (3c) according to its positioning one of a plurality of storage areas (5a, 5b) is supplied.

5. The method according to any one of the above claims,

characterized ,

in that the movement of the material (1) relative to the contact surface (7a, 7b) is an orthogonal or oblique impact on the contact surface (7a) or a sliding along the contact surface (7b).

6. The method according to any one of the above claims,

characterized ,

the sound sensor (6) has a directional characteristic.

7. Method according to one of the above claims,

characterized ,

in that the noise (G) detected during the time interval (T) is first filtered by the evaluation device (8) during the evaluation and then further processed.

8. The method according to any one of the above claims,

characterized ,

an ambient noise (GU) is subtracted from the evaluation device (8) by the noise (G) detected during the time interval (T).

9. The method according to any one of claims 1 to 8,

characterized ,

that of the evaluation device (8) for determining the Materialeigenschaff

a resulting function (g) is determined as a linear combination of predetermined output functions (gi), wherein the output functions (gi) are weighted with a respective weighting factor (ai) into the resulting function (g), the weighting factors (ai) are determined so that a norm of the deviation of the resulting function (g) from a spectrum (S) of the noise (G) detected during the time interval (T) as an integral over the frequency (f) is minimal, for the respective material property a respective set of reference weighting factors (ail, ai2, ai3) is given, by which a respective reference function (gR1, gR2, gR3) is determined, and

- the material property based on a comparison of the resulting function (g) with the reference functions (gRl, gR2, gR3) or on the basis of a comparison of the determined weighting factors (ai) with the reference weighting factors (ail, ai2, ai3) of the respective reference function ( gR1, gR2, gR3).

10. The method according to claim 9,

characterized ,

the standard of deviation of the resulting function (g) from the respective reference function (gR1, gR2, gR3) is determined by the evaluation device (8) for determining the material property at a number of support points (16) and that the number of support points (16 ) is less than the number of output functions (gi) that enter the linear combination.

11. The method according to claim 9 or 10,

characterized ,

that the output functions (gi) are polynomial functions.

12. The method according to claim 9, 10 or 11,

characterized ,

the output functions (gi) are orthogonal functions.

13. The method according to any one of claims 9 to 12,

characterized ,

that the method is executed by the evaluation device (8) in a working mode, - That in a learning mode, the lumpy material (1) is promoted such that it contacts the contact surface (7 a, 7 b) and relative to the contact surface (7 a, 7 b) is moved, the evaluation device (8) the material property is specified and of the Evaluation device (8) several times

- By means of the at least one sound sensor (6) during a respective time interval (T) caused by the contact of the particulate material (1) with the contact surface (7a, 7b) and its movement relative to the contact surface (7a, 7b) noise ( G) is detected,

a respective resulting function (g) is determined as a linear combination of the given output functions (gi) for the respective time interval (T), the output functions (gi) being weighted with a respective weighting factor (ai) into the resulting function (G) come in, and

- For the respective time interval (T) the weighting factors (ai) are determined such that a norm of the deviation of the respective resulting function (g) from a spectrum (S) of the during the respective time interval (T) detected noise (G) minimal is and

in that the reference weighting factors (ai4) are determined by the evaluation device (8) in the learning mode on the basis of the totality of the weighting factors (ai) respectively determined for the time intervals (T) and assigned to the predetermined material property.

14. The method according to any one of claims 9 to 13,

characterized ,

that the time interval (T) is in one or two-digit seconds range.

15. The method according to any one of claims 9 to 14,

characterized ,

the time interval (T) is predetermined or that from the evaluation device (8) from the beginning of the time interval (T) a sound energy (E) of the detected noise (G) is determined and the time interval (T) from the evaluation device (8) is terminated when the accumulated sound energy (E) reaches an energy limit (E0).

16. The method according to any one of claims 1 to 8,

characterized ,

that the evaluation device (8)

dividing the time interval (T) into a plurality of subintervals (Τ '),

- For the subintervals (Τ ') in each case a proportion (q) is determined, to which the power of a power spectrum (S) during each sub-interval (Τ') detected noise (G) between a lower cutoff frequency (fl) and one above the lower limit frequency (fl) lying

upper limit frequency (f2), and

- the material property is determined on the basis of the proportion of subintervals (Τ ') in which the proportion (q) of the power is above a predetermined threshold value (qO).

17. The method according to claim 16,

characterized ,

the lower limit frequency (fl) is between 200 Hz and 1000 Hz and / or the upper limit frequency (f2) is between 500 Hz and 2000 Hz.

18. The method according to claim 16 or 17,

characterized ,

the subintervals (Τ ') have a maximum duration of 1 second, for example at a maximum of 100 ms, in particular between 20 ms and 80 ms, and that the time interval (T) corresponds to 20 to 100 subintervals (Τ').

19. The method according to claim 16, 17 or 18,

characterized ,

in that the evaluation device (8) determines the material property by means of a fuzzy logic (18) on the basis of the proportion of subintervals (Τ ') at which the proportion (q) of the power lies above the predetermined threshold value (q0).

20. Method according to one of the above claims, d a d e r c h e c e n e c e n e,

in that an evaluation signal (C) is given by the operator (14) to the evaluation device (8) and that the specification of the triggering signal (C) determines the beginning of a time interval (T).

21. Method according to one of the above claims,

characterized ,

in that the evaluation device (8) is assigned data (D) related to the lumpy material (1) and that the evaluation device (8) takes into account the data (D) in the context of the evaluation of the detected noise (G).

22. Method according to one of the above claims,

characterized ,

the evaluation device (8) outputs an information (I) representing the determined material property and / or stores this information (I) in the sense of a history.

23. Method according to one of the above claims,

characterized ,

that the evaluation device (8) compares the determined material property with an expected material property, and that the evaluation device (8) issues an alarm message (A) in the event of a deviation of the determined material property from the expected material property.

24. Method according to one of the above claims,

characterized ,

- That by means of several sound sensors (6) at each location a noise (G) is detected,

- That the detected noise (G) of the evaluation device (8) are supplied,

- Is determined by the evaluation device (8) based on the detected noise (G), at which location by the sound sensor arranged there (6) by the contact of the lumpy material (1) with the contact surface (7a, 7b) and whose movement relative to the contact surface (7a, 7b) caused noise (G) is detected, and

- That is checked by the evaluation device (8), if this place coincides with an expected location, and in the case of non-compliance, an alarm message (Α ') is issued.

25. Evaluation device for determining at least one material property of a lumpy material (1), comprising - a first input for supplying a detected sound (G),

- wherein the particulate material (1) by means of a conveyor (2) is promoted such that it contacts a contact surface (7 a, 7 b) of the conveyor (2) and relative to the contact surface (7 a, 7 b) is moved, and

- Wherein a by means of at least one sound sensor (6) by the contact of the lumpy material (1) with the contact surface (7a, 7b) and its movement relative to the contact surface (7a, 7b) caused noise (G) supplied to the first input of the evaluation device will, and

a processing device, wherein the processing device of the evaluation device automatically determines the material property by evaluating the noise (G) detected during a time interval (T).

26. Evaluation device according to claim 25,

marked by

a filter (11) for filtering the noise (G), the filter (11) preferably being a high-pass, low-pass or band-pass filter, and / or

- An amplitude limiter for limiting the amplitude of the noise (G).

27. Evaluation device according to one of claims 25 to 26, e e c e n e c e n e d e r c h

- A second input for supplying an ambient noise (GU), and a subtractor for subtracting the ambient noise (GU) from the noise (G).

28. Evaluation device according to claim 25 to 27,

characterized ,

in that the processing device implements a method according to one of claims 7 to 23.