A method and system for measuring coal powder fineness based on audio signals

Abstract

The present invention discloses a method for measuring coal powder fineness based on audio signals, comprising: arranging a plurality of audio signal collectors on the outer surface of the elbow portion of the coal powder pipe of a coal mill; wherein each of the audio signal collectors is used to collect audio signals generated by the collision of coal powder and the pipe wall when air is discharged from the coal powder pipe; detecting the wind speed and coal powder concentration in the coal powder pipe, and obtaining the audio signals collected by each of the audio signal collectors; comprehensively analyzing each of the audio signals to obtain corresponding audio characteristic values, and searching for coal powder fineness matching the audio characteristic values ​​according to a preset correspondence relationship of wind speed-coal powder concentration-coal powder fineness-audio characteristic values. The method for measuring coal powder fineness based on audio signals provided by the present invention can conveniently and efficiently realize online measurement of coal powder fineness. The present invention also discloses a coal powder fineness measurement system based on audio signals, and its beneficial effects are as described above.

Description

Technical Field

[0001] The present invention relates to the field of thermal power generation technology, and in particular to a method for measuring coal fineness based on audio signals. The present invention also relates to a system for measuring coal fineness based on audio signals. Background Art

[0002] In a thermal power plant, the coal mill is an important equipment.

[0003] A coal mill is a machine that breaks up coal lumps and grinds them into pulverized coal. It is an important auxiliary equipment for pulverized coal furnaces. The coal grinding process is the process by which coal is broken down and its surface area is continuously increased. Coal is ground into pulverized coal in the mill primarily through crushing, pulverizing, and grinding. Coal mills are widely used in industries such as thermal power generation, cement, silicate products, new building materials, refractories, fertilizers, ferrous and non-ferrous metal beneficiation, and glass and ceramics. They perform dry or wet grinding of various ores and other grindable materials.

[0004] Currently, after coal pulverizers grind coal into pulverized coal, they typically use ducted airflow to transport the pulverized coal. Factors such as the pulverizer's operating conditions, coal mass, and coal volume result in varying quality of the pulverized coal, primarily manifesting in significant variations in pulverized coal fineness. To improve pulverized coal combustion quality, the pulverized coal fineness must be within an optimal diameter range. Generally speaking, the key factors influencing pulverized coal fineness, in addition to the pulverizer's operating conditions, are related to two key parameters: the pulverized coal pipe air volume and pulverized coal concentration.

[0005] In the existing technology, key parameters of the coal mill, such as the coal powder pipe air volume and coal powder concentration, have been measured online in real time. However, the measurement of coal powder fineness has always been difficult. Usually, the coal powder fineness can only be known after the coal powder has completed the transportation operation in the pipeline and the coal powder is sampled and tested for size. This method is not only cumbersome and labor-intensive, but also has a certain degree of lag in the subsequent adjustment of the coal mill operating conditions, coal powder pipe air volume, coal powder concentration and other parameters, making it difficult to achieve online measurement of coal powder fineness in the coal powder pipe.

[0006] Therefore, how to conveniently and efficiently realize online measurement of coal powder fineness is a technical problem faced by those skilled in the art. Summary of the Invention

[0007] The present invention aims to provide a method for measuring coal fineness based on audio signals, which can conveniently and efficiently realize online measurement of coal fineness. Another object of the present invention is to provide a system for measuring coal fineness based on audio signals.

[0008] To solve the above technical problems, the present invention provides a method for measuring coal powder fineness based on audio signals, comprising:

[0009] A plurality of audio signal collectors are provided on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill; wherein each of the audio signal collectors is used to collect the audio signal generated by the collision between the pulverized coal pipe and the pipe wall when the pulverized coal pipe is discharged;

[0010] detecting the wind speed and coal powder concentration in the coal powder pipe, and obtaining the audio signals collected by each of the audio signal collectors;

[0011] The audio signals are comprehensively analyzed to obtain corresponding audio characteristic values, and according to the preset corresponding relationship of wind speed-coal powder concentration-coal powder fineness-audio characteristic value, the coal powder fineness matching the audio characteristic value is searched.

[0012] Preferably, before setting the audio signal collector, the method further includes:

[0013] Installing the pulverized coal pipe on a pulverized coal fineness meter calibration device;

[0014] According to the preset different wind speeds and coal powder concentrations, the preset coal powder of different finenesses is introduced into the coal powder pipe, and the coal powder fineness meter calibration device is used to sequentially detect the audio characteristic values ​​in the coal powder pipe under different states;

[0015] A standard relationship comparison table of the four is made based on the audio characteristic values ​​of each test and the wind speed, coal powder concentration and coal powder fineness corresponding to the current test state.

[0016] Preferably, a plurality of audio signal collectors are provided on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill, specifically including:

[0017] Each of the audio signal collectors is arranged on the outer edge of the elbow portion of the pulverized coal pipe and is distributed in an arc shape along the moving direction of the pulverized coal.

[0018] Preferably, a plurality of audio signal collectors are provided on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill, and further comprising:

[0019] A portion of the audio signal collectors are distributed along the arc line with the maximum curvature radius of the elbow portion of the pulverized coal pipe, and another portion of the audio signal collectors are distributed symmetrically along the outer edge surface of the elbow portion of the pulverized coal pipe with the arc line with the maximum curvature radius as the symmetry axis.

[0020] Preferably, a plurality of audio signal collectors are provided on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill, and further comprising:

[0021] The distribution density of the audio signal collectors on the outer edge of the elbow portion of the pulverized coal pipe is adjusted according to the corresponding relationship between the density of collisions between each area of ​​the inner wall of the elbow portion of the pulverized coal pipe and the pulverized coal.

[0022] Preferably, comprehensively analyzing each of the audio signals to obtain corresponding audio feature values ​​specifically includes:

[0023] The audio feature values ​​corresponding to the respective audio signals are extracted respectively, and a weighted average value of the audio features is calculated according to a preset proportional weighting relationship.

[0024] Preferably, according to the preset correspondence relationship among wind speed, coal powder concentration, coal powder fineness, and audio characteristic value, when searching for the coal powder fineness that matches the audio characteristic value:

[0025] If the detected wind speed value is between two adjacent wind speed values ​​in the standard relationship comparison table, the corresponding two wind speed values ​​are used as reference items for sequential matching, and the average of the coal powder fineness in the two matching results is taken.

[0026] Preferably, according to the preset correspondence relationship among wind speed, coal powder concentration, coal powder fineness, and audio characteristic value, when searching for the coal powder fineness that matches the audio characteristic value:

[0027] If the detected value of pulverized coal concentration is between two adjacent levels of pulverized coal concentration values ​​in the standard relationship comparison table, the corresponding two levels of pulverized coal concentration values ​​are used as reference items for sequential matching, and the average of the pulverized coal fineness in the two matching results is taken.

[0028] Preferably, according to the preset correspondence relationship among wind speed, coal powder concentration, coal powder fineness, and audio characteristic value, when searching for the coal powder fineness that matches the audio characteristic value:

[0029] If the audio feature value is not the same as any data in the standard relationship comparison table, the data with the smallest difference from the audio feature value is taken as the reference value for matching.

[0030] The present invention also provides a coal powder fineness measurement system based on audio signals, comprising:

[0031] A probe installation module is used to set multiple audio signal collectors on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill; wherein each of the audio signal collectors is used to collect audio signals generated by the collision of coal powder with the pipe wall when air is discharged from the pulverized coal pipe;

[0032] a data detection module, configured to detect the wind speed and coal powder concentration in the coal powder pipe, and obtain the audio signals collected by each of the audio signal collectors;

[0033] The analysis and matching module is used to comprehensively analyze each of the audio signals to obtain corresponding audio feature values, and to search for the coal powder fineness that matches the audio feature value based on the preset corresponding relationship between wind speed, coal powder concentration, coal powder fineness and audio feature value.

[0034] The method for measuring pulverized coal fineness based on audio signals provided by the present invention comprises three main steps. The first step primarily involves the installation and placement of audio signal collectors. Specifically, multiple audio signal collectors are simultaneously installed on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill. These audio signal collectors are primarily used to collect audio signals. Since pulverized coal collides with the outer pipe wall at the elbow portion during transportation within the pulverized coal pipe, the audio signal collectors are primarily located on the outer surface of the elbow portion, corresponding to the impact area. Therefore, they can accurately capture the audio signals generated by the collision between pulverized coal and the pipe wall during air discharge. The second step primarily involves the acquisition of key parameters, namely, the detection of wind speed and pulverized coal concentration within the pulverized coal pipe, and the acquisition of audio signals collected by each audio signal collector. The third step primarily involves the calculation of pulverized coal fineness. First, the audio signals are comprehensively analyzed. Since the pulverized coal impact location is not a single point or a few points, but rather a large area, the analysis of all audio signals can yield audio feature values ​​corresponding to the actual situation. Then, based on the analyzed audio characteristic values ​​and the detected wind speed and coal powder concentration parameters, they are substituted into the preset correspondence between wind speed, coal powder concentration, coal powder fineness, and audio characteristic values, and the coal powder fineness parameters that match the analyzed audio characteristic values ​​under the current wind speed and coal powder concentration environment are found. In this way, the coal powder fineness measurement method based on audio signals provided by the present invention can conveniently and efficiently realize online measurement of coal powder fineness by real-time acquisition of the audio signal generated by the collision of coal powder with the inner wall of the coal powder pipe and real-time detection of the wind speed and coal powder concentration parameters in the coal powder pipe, and then matching the coal powder fineness with the wind speed, coal powder concentration, and audio characteristic values ​​of the audio signal. Compared with the existing technology, the present invention can realize online and real-time coal powder fineness detection, thereby timely adjusting the parameters such as the working conditions, wind speed, and coal powder concentration of the coal mill to obtain the target coal powder fineness. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are merely embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0036] Figure 1 The present invention provides a method flow chart of a specific implementation method.

[0037] Figure 2 Schematic diagram of the distribution of audio signal collectors on the pulverized coal pipe.

[0038] Figure 3It is a standard relationship comparison table of wind speed-coal powder concentration-coal powder fineness-audio frequency characteristic value.

[0039] Figure 4 A system module diagram of a specific implementation method provided by the present invention.

[0040] in, Figure 2 、 4 middle:

[0041] Pulverized coal pipe—1, audio signal collector—2, probe installation module—3, data detection module—4, analysis and matching module—5. DETAILED DESCRIPTION

[0042] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0043] Please refer to Figure 1 , Figure 1 This is a schematic diagram of the overall structure of a specific implementation method provided by the present invention.

[0044] In a specific embodiment provided by the present invention, the method for measuring coal fineness based on audio signals mainly comprises three steps, namely:

[0045] S1. Multiple audio signal collectors 2 are provided on the outer surface of the elbow portion of the pulverized coal pipe 1 of the coal mill; wherein each audio signal collector 2 is used to collect the audio signal generated by the collision between the pulverized coal pipe 1 and the pipe wall during air discharge;

[0046] S2, detecting the wind speed and coal powder concentration in the coal powder pipe 1, and obtaining the audio signals collected by each audio signal collector 2;

[0047] S3. Comprehensively analyze each audio signal to obtain a corresponding audio characteristic value, and search for a coal powder fineness that matches the audio characteristic value based on a preset correspondence relationship of wind speed-coal powder concentration-coal powder fineness-audio characteristic value.

[0048] Among them, in step S1, the main content is the installation and arrangement of the audio signal collector 2. Specifically, it is necessary to simultaneously set multiple audio signal collectors 2 on the outer surface of the elbow part of the coal powder pipe 1 of the coal mill. The audio signal collector 2 is mainly used to collect audio signals. Since the coal powder will collide with the outer pipe wall at the elbow part when being transported in the coal powder pipe 1, and each audio signal collector 2 is mainly distributed on the outer surface of the elbow part of the coal powder pipe 1, that is, the position corresponding to the impact area, it can accurately capture the audio signal generated by the collision of coal powder and the pipe wall when the air is discharged from the coal powder pipe 1.

[0049] In step S2 , the main content is key parameter collection, which includes detecting the wind speed and coal powder concentration in the coal powder pipe 1 , and obtaining the audio signals collected by each audio signal collector 2 .

[0050] Step S3 primarily involves calculating coal fineness. First, a comprehensive analysis of the audio signals is performed. Because the impact of coal dust occurs not at a single point or a few points, but over a large area, comprehensive analysis of all the audio signals yields audio eigenvalues ​​corresponding to the actual situation. The analyzed audio eigenvalues, along with the detected wind speed and coal dust concentration parameters, are then substituted into a pre-defined relationship between wind speed, coal dust concentration, coal dust fineness, and audio eigenvalues. The resulting coal fineness parameter, under the current wind speed and coal dust concentration, is found to match the analyzed audio eigenvalues.

[0051] In this way, the coal powder fineness measurement method based on audio signals provided in this embodiment can conveniently and efficiently realize online measurement of coal powder fineness by real-time collection of the audio signal generated by the collision of coal powder with the inner wall of the coal powder pipe 1 and real-time detection of the wind speed and coal powder concentration parameters in the coal powder pipe 1, and then matching according to the correspondence between coal powder fineness and wind speed, coal powder concentration and audio characteristic values ​​of the audio signal; compared with the existing technology, this embodiment can realize coal powder fineness detection online and in real time, so as to timely adjust the operating conditions, wind speed, coal powder concentration and other parameters of the pulverizer to obtain the target coal powder fineness.

[0052] Taking into account that the corresponding relationship between wind speed, coal powder concentration, coal powder fineness and audio characteristic value may vary for coal powder pipes 1 of different specifications, in order to maximize the measurement accuracy of coal powder fineness, this embodiment further adds a pre-order step of establishing the corresponding relationship between wind speed, coal powder concentration, coal powder fineness and audio characteristic value for the currently measured coal powder pipe 1 before setting the audio signal collector 2 for the coal powder pipe 1.

[0053] Specifically, the on-site establishment operation of the correspondence between wind speed, coal powder concentration, coal powder fineness and audio characteristic value requires the use of a coal powder fineness meter calibration device. First, the coal powder pipe 1 is installed on the coal powder fineness meter calibration device, and then the correspondence between wind speed, coal powder concentration, coal powder fineness and audio characteristic value is obtained through the coal powder fineness meter calibration device: mainly according to the preset different wind speeds and coal powder concentrations, preset coal powders of different known finenesses are introduced into the coal powder pipe 1, and then the coal powder fineness meter calibration device is used to detect the audio characteristic values ​​in the coal powder pipe 1 under various states in turn.

[0054] For example, using the initial wind speed and initial coal powder concentration as the initial state, pulverized coal of an initial fineness is passed through pulverized coal pipe 1. After the pulverized coal is transported for a certain period of time until the state stabilizes, the audio characteristic values ​​in the pulverized coal pipe 1 under the current state are measured using a pulverized coal fineness meter calibration device, thereby obtaining a set of corresponding relationships between wind speed, coal powder concentration, coal powder fineness, and audio characteristic values. This process is repeated, and in each subsequent test, a single variable is gradually changed using the control variable method to obtain multiple sets of corresponding relationships between wind speed, coal powder concentration, coal powder fineness, and audio characteristic values. In this way, after obtaining sufficient data, the corresponding relationships between each set of wind speed, coal powder concentration, coal powder fineness, and audio characteristic values ​​can be integrated to obtain a standard relationship comparison table for the wind speed, coal powder concentration, coal powder fineness, and audio characteristic values ​​of the current pulverized coal pipe 1.

[0055] like Figure 3 As shown, Figure 3 This table represents a standardized relationship between wind speed, coal powder concentration, coal powder fineness, and audio eigenvalues. For example, if coal powder fineness X = 1, then when wind speed V and coal powder concentration N change step by step, there will always be an audio eigenvalue T (or range) corresponding to a specific state. Therefore, when measuring, given wind speed V, coal powder concentration N, and audio eigenvalue T, these three values ​​can be substituted into the standard relationship table to find the corresponding coal powder fineness X.

[0056] Obviously, when the coal powder fineness X changes, the above standard relationship comparison table also changes accordingly.

[0057] like Figure 2 As shown, Figure 2 Schematic diagram of the distribution of audio signal collectors 2 on the pulverized coal pipe 1.

[0058] In step S1, it is considered that when the coal powder collides with the inner wall of the coal powder pipe 1, the overall characteristics are a large impact area, a wide impact area, and a scattered impact position distribution. Under ideal conditions, the airflow moves along the center line of the elbow part and is evenly distributed with the center line as the center of the circle. However, due to the mass of the airflow and coal powder, the movement of the airflow is affected by the characteristics of the coal powder and the pipeline itself. Therefore, when moving at the elbow part of the coal powder pipe 1, the wind and powder mixture collides with the outer inner wall of the coal powder pipe 1 under the action of centrifugal force and gravity. In this way, when there is no turbulence in the wind, the wind and powder mixture collides with the outer inner wall of the elbow part symmetrically with the center plane. At the same time, due to the differences in wind speed and coal powder fineness, the centrifugal force is different, so the position of the collision with the coal powder pipe 1 will also be different.

[0059] To address this issue, in this embodiment, the audio signal collectors 2 are positioned at the outer edge of the elbow of the pulverized coal pipe 1 and distributed in an arc along the direction of coal movement. This arrangement ensures that the audio signal collectors 2 capture the entire signal area of ​​the elbow, effectively covering the impact zone, and thus improving the reliability of the detection results.

[0060] Furthermore, this embodiment also distributes a portion of the audio signal collectors 2 along the arc line of the maximum curvature radius of the elbow portion of the pulverized coal pipe 1, while distributing another portion of the audio signal collectors 2 symmetrically along the outer edge of the elbow portion of the pulverized coal pipe 1, with the arc line of the maximum curvature radius serving as the axis of symmetry. For example, four audio signal collectors 2 can be arranged along the arc line of the maximum curvature radius of the elbow portion of the pulverized coal pipe 1, while two to three pairs of audio signal collectors 2 are symmetrically distributed along the annular direction on both sides of the arc line of the maximum curvature radius. Each audio signal collector 2 maintains an arc-shaped distribution along the arc structure of the elbow portion of the pulverized coal pipe 1. With this arrangement, the audio signal collectors 2 are generally distributed in a ring-shaped or arc-shaped network on the elbow portion of the pulverized coal pipe 1, further improving measurement accuracy.

[0061] Not only that, considering the influence of aerodynamics, the collision of coal powder with the inner wall of the elbow part of the coal powder pipe 1 when the coal powder moves with the air flow may be different, which is mainly reflected in the density of the collision positions - generally, the density of the collision positions between the coal powder and the inner wall of the elbow part of the coal powder pipe 1 facing the air outlet is higher, while the density of the collision positions between the coal powder and the inner wall of the elbow part of the coal powder pipe 1 facing the air inlet is lower. In view of this, this embodiment adjusts the distribution density of each audio signal collector 2 on the outer edge of the elbow part of the coal powder pipe 1 according to this characteristic, so that the distribution density of the audio signal collector 2 in the area with dense collisions is also higher, and vice versa.

[0062] In step S3, when analyzing the audio eigenvalues, the audio eigenvalues ​​corresponding to each audio signal are first extracted. Then, a weighted average of these eigenvalues ​​is calculated based on a preset weighted relationship. For example, the audio eigenvalue corresponding to the audio signal at the center of the collision area is given a higher weighting, while the weighted average is lower. This makes the calculated audio eigenvalues ​​more reliable.

[0063] In addition, when searching for the coal powder fineness that matches the audio feature value based on the preset correspondence between wind speed, coal powder concentration, coal powder fineness and audio feature value, if the detected value of the wind speed is between two adjacent wind speed values ​​in the standard relationship comparison table, the corresponding two wind speed values ​​are used as reference items for matching in sequence, and the average of the coal powder fineness in the two matching results is taken.

[0064] Similarly, if the detected value of pulverized coal concentration is between two adjacent levels of pulverized coal concentration values ​​in the standard relationship comparison table, the corresponding two levels of pulverized coal concentration values ​​are used as reference items for matching in sequence, and the average of the pulverized coal fineness in the two matching results is taken.

[0065] When the detected value of wind speed is between two adjacent wind speed values ​​in the standard relationship comparison table, and the detected value of pulverized coal concentration is also between two adjacent pulverized coal concentration values ​​in the standard relationship comparison table, the corresponding two-level wind speed values ​​and the four endpoint values ​​corresponding to the two-level pulverized coal concentration values ​​can be used for combination matching, and then the average value processing is performed according to the corresponding four audio feature values, and finally the corresponding pulverized coal fineness is matched according to the average value of the audio feature values.

[0066] For example, V0 is between V1 and V2, and N0 is between N1 and N2, which correspond to four audio feature values: T11, T12, T21, and T22 respectively. Then, the average value Ta of T11, T12, T21, and T22 is calculated by proportion, and finally matching is performed based on Ta.

[0067] In addition, if the audio feature value is not the same as any data in the standard relationship comparison table, the data with the smallest difference from the audio feature value is taken as the reference value for matching.

[0068] like Figure 4 As shown, Figure 4 A system module diagram of a specific implementation method provided by the present invention.

[0069] This embodiment also provides a coal powder fineness measurement system based on audio signals, which mainly includes a probe installation module 3, a data detection module 4, and an analysis and matching module 5. The probe installation module 3 is mainly used to install multiple audio signal collectors 2 on the outer surface of the elbow portion of the coal powder pipe 1 of the coal mill; each audio signal collector 2 is used to collect audio signals generated by the collision between coal powder and the pipe wall when air is discharged from the coal powder pipe 1. The data detection module 4 is mainly used to detect the wind speed and coal powder concentration in the coal powder pipe 1 and obtain the audio signals collected by each audio signal collector 2. The analysis and matching module 5 is mainly used to comprehensively analyze each audio signal to obtain the corresponding audio feature value, and according to the preset correspondence between wind speed, coal powder concentration, coal powder fineness, and audio feature value, search for the coal powder fineness that matches the audio feature value.

[0070] In addition, to ensure the stability of the collected audio signal, it is necessary to ensure the stability of the coal powder flowing with the air. However, elbows, valves, etc. will disturb the air flow, which in turn causes uncertainty in the coal powder flow and uncertainty in the characteristics of the audio signal collected at the elbow. Therefore, it is necessary to leave sufficient straight pipe sections before and after the elbow of the coal powder pipe 1. The required length of the shortest straight pipe section varies depending on the wind speed range, coal powder fineness range, and measurement accuracy requirements of the measured object. The specific length needs to be determined based on the above three factors. Generally speaking, the greater the wind speed, the longer the straight pipe section length is required; the higher the accuracy, the longer the straight pipe section is required; and the smaller the particle size, the longer the straight pipe section is required. The straight pipe section length is usually a multiple of the elbow diameter.

[0071] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for measuring coal powder fineness based on audio signals, characterized in that: include: A plurality of audio signal collectors are provided on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill; wherein each of the audio signal collectors is used to collect the audio signal generated by the collision between the pulverized coal pipe and the pipe wall when the pulverized coal pipe is discharged; detecting the wind speed and coal powder concentration in the coal powder pipe, and obtaining the audio signals collected by each of the audio signal collectors; Comprehensively analyzing each of the audio signals to obtain a corresponding audio characteristic value, and searching for a coal powder fineness that matches the audio characteristic value based on a preset correspondence relationship between wind speed, coal powder concentration, coal powder fineness, and audio characteristic value; before setting the audio signal collector, the method further includes: Installing the pulverized coal pipe on a pulverized coal fineness meter calibration device; According to the preset different wind speeds and coal powder concentrations, the preset coal powder of different finenesses is introduced into the coal powder pipe, and the coal powder fineness meter calibration device is used to sequentially detect the audio characteristic values ​​in the coal powder pipe under different states; A standard relationship comparison table of the four is made based on the audio characteristic values ​​of each test and the wind speed, coal powder concentration and coal powder fineness corresponding to the current test state.

2. The method for measuring coal powder fineness based on audio signals according to claim 1, characterized in that: A plurality of audio signal collectors are provided on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill, specifically including: Each of the audio signal collectors is arranged on the outer edge of the elbow portion of the pulverized coal pipe and is distributed in an arc shape along the moving direction of the pulverized coal.

3. The method for measuring coal powder fineness based on audio signals according to claim 2, characterized in that: A plurality of audio signal collectors are arranged on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill, and further comprising: A portion of the audio signal collectors are distributed along the arc line with the maximum curvature radius of the elbow portion of the pulverized coal pipe, and another portion of the audio signal collectors are distributed symmetrically along the outer edge surface of the elbow portion of the pulverized coal pipe with the arc line with the maximum curvature radius as the symmetry axis.

4. The method for measuring coal powder fineness based on audio signals according to claim 3, characterized in that: A plurality of audio signal collectors are arranged on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill, and further comprising: The distribution density of the audio signal collectors on the outer edge of the elbow portion of the pulverized coal pipe is adjusted according to the corresponding relationship between the density of collisions between each area of ​​the inner wall of the elbow portion of the pulverized coal pipe and the pulverized coal.

5. The method for measuring coal powder fineness based on audio signals according to claim 1, characterized in that: Comprehensively analyzing each of the audio signals to obtain corresponding audio feature values, specifically including: The audio feature values ​​corresponding to the respective audio signals are extracted respectively, and a weighted average value of the audio feature values ​​is calculated according to a preset proportional weighting relationship.

6. The method for measuring coal powder fineness based on audio signals according to any one of claims 1 to 5, characterized in that: According to the preset correspondence between wind speed, coal powder concentration, coal powder fineness and audio characteristic value, when searching for the coal powder fineness that matches the audio characteristic value: If the detected wind speed value is between two adjacent wind speed values ​​in the standard relationship comparison table, the corresponding two wind speed values ​​are used as reference items for sequential matching, and the average of the coal powder fineness in the two matching results is taken.

7. The method for measuring coal powder fineness based on audio signals according to claim 6, characterized in that: According to the preset correspondence between wind speed, coal powder concentration, coal powder fineness and audio characteristic value, when searching for the coal powder fineness that matches the audio characteristic value: If the detected value of pulverized coal concentration is between two adjacent levels of pulverized coal concentration values ​​in the standard relationship comparison table, the corresponding two levels of pulverized coal concentration values ​​are used as reference items for sequential matching, and the average of the pulverized coal fineness in the two matching results is taken.

8. The method for measuring coal powder fineness based on audio signals according to claim 7, characterized in that: According to the preset correspondence between wind speed, coal powder concentration, coal powder fineness and audio characteristic value, when searching for the coal powder fineness that matches the audio characteristic value: If the audio feature value is not the same as any data in the standard relationship comparison table, the data with the smallest difference from the audio feature value is taken as the reference value for matching.

9. A measurement system for the method for measuring coal powder fineness based on audio signals according to any one of claims 1 to 8, characterized in that: include: A probe installation module is used to set multiple audio signal collectors on the outer surface of the elbow portion of the pulverized coal pipe of the coal mill; wherein each of the audio signal collectors is used to collect audio signals generated by the collision of coal powder with the pipe wall when air is discharged from the pulverized coal pipe; a data detection module, configured to detect the wind speed and coal powder concentration in the coal powder pipe, and obtain the audio signals collected by each of the audio signal collectors; The analysis and matching module is used to comprehensively analyze each of the audio signals to obtain corresponding audio feature values, and to search for the coal powder fineness that matches the audio feature value based on the preset corresponding relationship between wind speed, coal powder concentration, coal powder fineness and audio feature value.

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