A conveying belt state monitoring method based on an array air-coupled ultrasonic probe

Abstract

The application discloses a kind of based on array air coupling ultrasonic probe's conveying belt state monitoring method, comprising the following steps: (1) setting position encoder to locate the position of the conveying belt is obtained;Setting top detection array probe group, bottom detection array probe group, left side detection array probe group and right side detection array probe group;(2) top detection array probe group emits ultrasonic wave signal to the upper surface of conveying belt, and receives reflected signal, to monitor the real-time coal mine flow on conveying belt;Bottom detection array probe group, left side detection array probe group, right side detection array probe group emit ultrasonic wave signal to conveying belt, and receive reflected signal, to monitor the longitudinal tear crack of conveying belt;(3) realize multi-channel data synchronous acquisition by central processing unit: (3-1) signal acquisition;(3-2) data processing;(3-3) data interpretation;(3-4) result output.The application can realize multidirectional monitoring, improve the identification sensitivity of longitudinal tear, reduce false positive rate and false negative rate.

Description

Technical Field

[0001] This invention relates to the field of coal mine equipment monitoring technology, and in particular to a method for monitoring the condition of conveyor belts based on an array of air-coupled ultrasonic probes. Background Technology

[0002] In the process of intelligent coal mine construction, conveyor belts, as the core equipment of the main and auxiliary transportation system, undertake the critical task of continuous coal transportation. Their operating status (such as longitudinal tearing failure and coal flow stability) directly affects coal mine production efficiency and operational safety. The "Guiding Opinions on Accelerating the Intelligent Development of Coal Mines" clearly requires the promotion of intelligent optimization and upgrading of main and auxiliary transportation and safety monitoring in coal mines, achieving unmanned operation of fixed positions and robotic operation of hazardous positions, and constructing an intelligent system of intelligent perception, intelligent decision-making, and automatic execution. However, existing coal mine conveyor belt condition monitoring technology still has many shortcomings and is difficult to adapt to the needs of intelligent development. Specific deficiencies are as follows:

[0003] 1. The monitoring functions are fragmented, making integrated and synchronous monitoring impossible.

[0004] In existing technologies, coal flow monitoring and conveyor belt tear monitoring often rely on two separate sets of equipment: coal flow monitoring typically uses a single ultrasonic probe or weighing sensor, while tear monitoring relies on specialized equipment such as infrared sensors and pressure sensors. The independent operation of these two systems leads to problems such as asynchronous data acquisition, high equipment installation and maintenance costs, and large space requirements. Furthermore, manual integration of the two types of data is necessary, failing to meet the requirements for intelligent real-time sensing and collaborative decision-making.

[0005] 2. The longitudinal tear monitoring system has blind spots and a low fault identification rate.

[0006] Longitudinal tearing faults in conveyor belts can occur on the upper surface, lower surface, and left and right sides. Hidden longitudinal tears on the lower surface and sides, in particular, are prone to widening due to early detection, potentially leading to major accidents such as conveyor belt breakage and coal leakage. Existing longitudinal tear monitoring equipment mostly targets a single surface (such as the upper surface or a localized side), employing a single-point sensor layout with limited coverage and significant monitoring blind spots. Traditional sensors have low sensitivity to minor longitudinal tears, resulting in high false alarm and false negative rates, failing to provide early warning of faults. Summary of the Invention

[0007] The problem to be solved by the present invention is to provide a conveyor belt condition monitoring method based on an array of air-coupled ultrasonic probes. This conveyor belt condition monitoring method based on an array of air-coupled ultrasonic probes can realize multi-directional monitoring, with a large coverage area, improve the identification sensitivity of longitudinal tears, and reduce the false alarm rate and the missed alarm rate.

[0008] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0009] A method for monitoring the condition of a conveyor belt based on an array-coupled ultrasonic probe, characterized by comprising the following steps:

[0010] (1) Set a position encoder to locate and obtain the position of the conveyor belt; set a top detection array probe group, a bottom detection array probe group, a left detection array probe group and a right detection array probe group; the top detection array probe group is set above the upper surface of the conveyor belt, the bottom detection array probe group is set below the lower surface of the conveyor belt, the left detection array probe group is set on the left side of the left side of the conveyor belt, and the right detection array probe group is set on the right side of the right side of the conveyor belt, and the right detection array probe group corresponds to the left detection array probe group; the top detection array probe group, the bottom detection array probe group, the left detection array probe group and the right detection array probe group each include multiple probes;

[0011] (2) The top detection array probe group emits ultrasonic signals to the upper surface of the conveyor belt and receives reflected signals to monitor the real-time coal flow on the conveyor belt; the bottom detection array probe group emits ultrasonic signals to the lower surface of the conveyor belt and receives reflected signals to monitor the longitudinal tear of the conveyor belt; the left detection array probe group emits ultrasonic signals to the left side of the conveyor belt and receives reflected signals to monitor the longitudinal tear of the conveyor belt; the right detection array probe group emits ultrasonic signals to the right side of the conveyor belt and receives reflected signals to monitor the longitudinal tear of the conveyor belt.

[0012] (3) Realize synchronous acquisition of multi-channel data through the central processing unit:

[0013] (3-1) Signal acquisition: The central processing unit synchronously and in real time acquires data from the top detection array probe group, bottom detection array probe group, left detection array probe group and right detection array probe group through all parallel channels, records the reflection echo time and reflection echo amplitude of each probe in real time, and calculates the probe ranging distance.

[0014] (3-2) Data processing: As the conveyor belt runs, the position of the conveyor belt is obtained by positioning the position encoder. The probe ranging distance at different conveyor belt positions is continuously collected. Then, a ranging continuous recording curve of "conveyor belt position - probe ranging distance" is plotted based on the reflection echo time of each probe.

[0015] (3-3) Data Interpretation:

[0016] (3-3.1) Based on the ranging data of the reflected signals received by the top detection array probe group, calculate the instantaneous flow rate per second and the total flow rate of the coal mine according to the coal mine flow monitoring method;

[0017] (3-3.2) Based on the ranging data of the reflected signals received by the left detection array probe group and the right detection array probe group, the longitudinal tear seam of the conveyor belt is automatically detected;

[0018] (3-3.3) Based on the ranging data of the reflected signals received by the bottom detection array probe group, the longitudinal tear seam of the conveyor belt is automatically detected;

[0019] (3-4) Output results: Output the instantaneous coal quantity, total coal quantity, and whether the longitudinal tearing status is abnormal.

[0020] In the preferred embodiment, the specific steps for signal acquisition in step (3-1) are as follows:

[0021] (3-1.1) Based on the reflected echo signal after the probe encounters the coal surface or conveyor belt surface, conveyor belt bottom surface, or left and right sides of the conveyor belt, measure and record the peak time of the first peak of the reflected echo signal as the reflected echo time, and measure and record the amplitude of the highest amplitude of the reflected echo signal as the reflected echo amplitude.

[0022] (3-1.2) The probe ranging distance is calculated using the formula d=0.5vt based on the reflection echo time; where: d is the distance from the probe to the reflecting surface of the object being tested, in meters; v is the speed of sound in air, v is 340 m / s; t is the round-trip propagation time of the ultrasonic wave emitted by the probe, in seconds.

[0023] In the preferred embodiment, in step (3-2), the data processing involves using the least squares method to perform curve fitting on the data collected from each probe ranging distance point to obtain a continuous ranging record curve for a single probe.

[0024] In a further preferred embodiment, the continuous ranging recording curve graph also includes a ranging positive error reference line, a ranging theoretical reference line, and a ranging negative error reference line arranged sequentially from top to bottom. When the ranging distance point of each probe is between the ranging positive error reference line and the ranging negative error reference line, the ranging distance point of that probe is considered valid data. When the ranging distance point of each probe is higher than the ranging positive error reference line or lower than the ranging negative error reference line, the ranging distance point of that probe is considered invalid data by default.

[0025] In a further preferred embodiment, the operational steps of the coal mine flow monitoring method in step (3-3.1) are as follows:

[0026] (3-3.1.1) Measure the distance from the coal mine surface to each probe through each probe of the top detection array probe group, and plot the coal surface fitting curve;

[0027] (3-3.1.2) Through approximation, assume that the top detection array probe group has a probes set at the same height, where a is an integer greater than 0; the arrangement length of the a probes and the structure of the conveyor belt form the total profile cross-section, and the total profile cross-sectional area S is calculated by the formula S=L1*D1-(L1-L2)*(D1-D2) / 2, where S is in square meters, where: L1 is the arrangement length of each probe in the top detection array probe group, in meters; L2 is the straight length of the bottom of the conveyor belt, in meters; D1 is the height of each probe in the top detection array probe group from the straight position of the bottom of the conveyor belt, in meters; D2 is the height of the outermost probe of the top detection array probe group from the inclined side of the conveyor belt, in meters;

[0028] (3-3.1.3) The cross-sectional area S2 of the coal mine is calculated using the formulas S2=S-S1 and S1=L1*(d1+d2+...+da) / a. The unit of S2 is square meters. S1 is the air cross-sectional area formed by the a probes of the top detection array and the coal mine surface. The unit of S1 is square meters. d1, d2, ..., da are the distances from the a probes to the coal mine surface, respectively, in meters.

[0029] Assuming the conveyor belt's transport speed is V meters per second, and the coal mine cross-sectional area S2 is calculated once every β meters it moves, the number of calculations required per second is n, where n = V / β, and the unit is calculations per second; β is in meters per calculation.

[0030] The formula for calculating the instantaneous flow rate per second in a coal mine is: Fs = The unit is cubic meters per second; S2(n) is the cross-sectional area of ​​the coal mine at the nth trigger, in square meters;

[0031] The formula for calculating the total flow rate of a coal mine is: Ft = Fs * t, where Ft is in cubic meters and t is the coal mine operating time in seconds.

[0032] In a further preferred embodiment, the steps for automatically detecting whether there is a longitudinal tear in the conveyor belt in step (3-3.2) based on the ranging data of the reflected signals received by the left and right detection array probe groups are as follows:

[0033] (3-3.2.1) The number of probes in the left detection array probe group is the same as the number of probes in the right detection array probe group and they are set symmetrically. The ranging data of the reflected signals received by the left detection array probe group and the right detection array probe group are synchronously compared and analyzed.

[0034] (3-3.2.2) When the conveyor belt does not have a longitudinal tear, the distance measured by each probe remains stable and the distance measured by each probe is within a certain error range. All the distance measured by each probe is between the positive error reference line and the negative error reference line.

[0035] (3-3.2.3) When a longitudinal tear occurs in the conveyor belt, if more than 5 consecutive probe distance measurement points are not between the positive and negative distance measurement reference lines within any consecutive 1-second time range, the conveyor belt is automatically judged to have a longitudinal tear; or if the ultrasonic signal cannot be received due to the conveyor belt deviating from the probe detection, resulting in distance measurement failure and no data display, the conveyor belt is automatically judged to have a longitudinal tear.

[0036] Because the conveyor belt is depressed by the pressure of the coal mine, the ranging distance of the probes located on the side of the conveyor belt will change. This can easily cause the probe ranging distance to exceed the range of the positive and negative ranging error reference lines. Therefore, it is necessary to detect whether there are longitudinal tears. The rule for determining the above error reference lines is: by statistically calculating a large amount of measured probe ranging distance data under conditions without longitudinal tears, it is determined that all probe ranging distance data are between the positive and negative ranging error reference lines.

[0037] In a further preferred embodiment, the steps for automatically detecting whether there is a longitudinal tear in the conveyor belt in step (3-3.3) based on the ranging data of the reflected signal received by the bottom detection array probe group are as follows:

[0038] (3-3.3.1) The probes of the bottom detection array probe group are arranged at equal intervals along the width direction and arc shape of the conveyor belt;

[0039] (3-3.3.2) When the conveyor belt does not have a longitudinal tear, at a certain moment, the distance measured by each probe remains stable, and the distance measured by each probe is within a certain error range. All the distance measured by the probes are between the positive error reference line and the negative error reference line.

[0040] (3-3.3.3) When a longitudinal tear occurs in the conveyor belt, if at a certain moment, more than 5 of the probes in the width direction of the conveyor belt have distance measurement points that are not between the positive and negative distance measurement error reference lines, then the conveyor belt is automatically determined to have a longitudinal tear; or if, within any consecutive 1-second time range, a single probe has more than 5 consecutive distance measurement points that are not between the positive and negative distance measurement error reference lines, then the conveyor belt is automatically determined to have a longitudinal tear.

[0041] In the preferred embodiment, in step (3-4), when the longitudinal tearing state is abnormal, an automatic feedback signal is sent to the conveyor belt system to automatically stop the machine; when the longitudinal tearing state is normal, the conveyor belt continues to transport coal.

[0042] In the preferred embodiment, in step (1), each probe is an array-coupled ultrasonic probe. The array-coupled ultrasonic probes of the top detection array probe group are distributed along the width direction of the conveyor belt, the array-coupled ultrasonic probes of the bottom detection array probe group are distributed along the width direction and arc shape of the conveyor belt, the array-coupled ultrasonic probes of the left detection array probe group are distributed along the length direction of the conveyor belt, and the array-coupled ultrasonic probes of the right detection array probe group are distributed along the length direction of the conveyor belt.

[0043] In a further preferred embodiment, the top detection array probe group has 8-12 array air-coupled ultrasonic probes, each array air-coupled ultrasonic probe is arranged at equal intervals along the width direction of the conveyor belt, and the distance between two adjacent array air-coupled ultrasonic probes is 100-200cm.

[0044] In a further preferred embodiment, the bottom detection array probe group has 8-12 array air-coupled ultrasonic probes, and each array air-coupled ultrasonic probe is arranged at equal intervals along the width direction and arc shape of the conveyor belt, with the spacing between two adjacent array air-coupled ultrasonic probes being 100-200cm.

[0045] In a further preferred embodiment, both the left and right detection array probe groups have 2-4 array air-coupled ultrasonic probes, and each array air-coupled ultrasonic probe is arranged at equal intervals along the length of the conveyor belt, with a spacing of 50-200cm between adjacent array air-coupled ultrasonic probes.

[0046] In a further preferred embodiment, the array-coupled ultrasonic probe is an ultrasonic transducer. The ultrasonic transducer uses an IP67-rated housing and operates within a temperature range of -20℃ to 85℃.

[0047] Compared with the prior art, the present invention has the following advantages:

[0048] This invention achieves simultaneous acquisition and fusion analysis of multi-channel data, featuring non-contact measurement, four-array collaborative multi-directional monitoring, comprehensive coverage, and strong environmental adaptability. It integrates precise coal flow measurement with comprehensive detection of longitudinal tear joints, improving the reliability and intelligence of coal mine conveyor belt monitoring, and is suitable for conveyor belt safety monitoring under various harsh working conditions. Attached Figure Description

[0049] Figure 1 This is a schematic diagram of the spatial arrangement of the probe groups monitored in an embodiment of the present invention;

[0050] Figure 2 yes Figure 1 A three-dimensional schematic diagram;

[0051] Figure 3 This is a flowchart of the signal processing according to an embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram illustrating the real-time acquisition of the reflected echo time and amplitude of the probe in an embodiment of the present invention;

[0053] Figure 5 This is a graph of the continuous distance measurement recording according to an embodiment of the present invention;

[0054] Figure 6 This is a schematic diagram of the coal surface fitting curve and overall profile section processing generated in an embodiment of the present invention;

[0055] Figure 7 This is a schematic diagram of the left and right detection array probe groups of an embodiment of the present invention detecting that there is no longitudinal tear in the conveyor belt;

[0056] Figure 8 This is a schematic diagram of the detection array probe groups on the left and right sides of the embodiment of the present invention detecting longitudinal tear seams in the conveyor belt;

[0057] Figure 9 This is a schematic diagram of the bottom detection array probe group detecting that there is no longitudinal tear in the conveyor belt according to an embodiment of the present invention;

[0058] Figure 10 This is a schematic diagram of the bottom detection array probe group detecting longitudinal tear seams in the conveyor belt according to an embodiment of the present invention. Detailed Implementation

[0059] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments.

[0060] The conveyor belt status monitoring method based on an array-coupled ultrasonic probe in this embodiment includes the following steps:

[0061] (1) Set a position encoder to locate and obtain the position of the conveyor belt 1; set a top detection array probe group 2, a bottom detection array probe group 3, a left detection array probe group 4 and a right detection array probe group 5; the top detection array probe group 2 is set above the upper surface of the conveyor belt 1, the bottom detection array probe group 3 is set below the lower surface of the conveyor belt 1, the left detection array probe group 4 is set on the left side of the left side of the conveyor belt 1, and the right detection array probe group 5 is set on the right side of the right side of the conveyor belt 1, and the right detection array probe group 5 corresponds to the left detection array probe group 4; the top detection array probe group 2, the bottom detection array probe group 3, the left detection array probe group 4 and the right detection array probe group 5 each include multiple probes 11;

[0062] (2) The top detection array probe group 2 emits ultrasonic signals to the upper surface of the conveyor belt 1 and receives reflected signals to monitor the real-time coal flow on the conveyor belt 1; the bottom detection array probe group 3 emits ultrasonic signals to the lower surface of the conveyor belt 1 and receives reflected signals to monitor the longitudinal tear of the conveyor belt 1; the left detection array probe group 4 emits ultrasonic signals to the left side of the conveyor belt 1 and receives reflected signals to monitor the longitudinal tear of the conveyor belt 1; the right detection array probe group 5 emits ultrasonic signals to the right side of the conveyor belt 1 and receives reflected signals to monitor the longitudinal tear of the conveyor belt 1.

[0063] (3) Realize synchronous acquisition of multi-channel data through the central processing unit:

[0064] (3-1) Signal acquisition: The central processing unit synchronously acquires data from the top detection array probe group 2, the bottom detection array probe group 3, the left detection array probe group 4 and the right detection array probe group 5 in parallel channels in real time, records the reflection echo time and reflection echo amplitude of each probe 11 in real time, and calculates the probe ranging distance.

[0065] (3-2) Data Processing: As conveyor belt 1 runs, the position of conveyor belt 1 is obtained based on the position encoder. The probe ranging distance at different positions of conveyor belt 1 is continuously collected. Then, based on the reflection echo time of each probe, a continuous ranging record curve of "conveyor belt position - probe ranging distance" is plotted, such as... Figure 5 As shown;

[0066] (3-3) Data Interpretation:

[0067] (3-3.1) Based on the ranging data of the reflected signal received by the top detection array probe group 2, calculate the instantaneous flow rate per second and the total flow rate of the coal mine according to the coal mine flow monitoring method;

[0068] (3-3.2) Based on the ranging data of the reflected signals received by the left detection array probe group 4 and the right detection array probe group 5, the longitudinal tear seam of the conveyor belt 1 is automatically detected.

[0069] (3-3.3) Based on the ranging data of the reflected signal received by the bottom detection array probe group 3, the longitudinal tear seam of the conveyor belt 1 is automatically detected;

[0070] (3-4) Output results: Output the instantaneous coal quantity, total coal quantity, and whether the longitudinal tearing status is abnormal.

[0071] like Figure 3-4 As shown, the specific steps for signal acquisition in step (3-1) are as follows:

[0072] (3-1.1) Based on the reflected echo signal after the probe encounters the coal surface or the surface of the conveyor belt 1, the bottom surface of the conveyor belt 1, or the left and right sides of the conveyor belt 1, measure and record the peak time of the first peak of the reflected echo signal as the reflected echo time, and measure and record the amplitude of the highest amplitude of the reflected echo signal as the reflected echo amplitude.

[0073] (3-1.2) The probe ranging distance is calculated using the formula d=0.5vt based on the reflection echo time; where: d is the distance from the probe to the reflecting surface of the object being tested, in meters; v is the speed of sound in air, v is 340 m / s; t is the round-trip propagation time of the ultrasonic wave emitted by the probe, in seconds.

[0074] In step (3-2), data processing involves using the least squares method to perform curve fitting on the data collected from each probe's ranging distance points, resulting in a continuous ranging record curve for a single probe (e.g., ...). Figure 5 (As shown).

[0075] like Figure 7-10 As shown, the continuous distance measurement recording curve also includes a distance measurement positive error reference line, a distance measurement theoretical reference line, and a distance measurement negative error reference line set from top to bottom. When the distance measurement point of each probe is between the distance measurement positive error reference line and the distance measurement negative error reference line, the distance measurement point of that probe is valid data; when the distance measurement point of each probe is higher than the distance measurement positive error reference line or lower than the distance measurement negative error reference line, the distance measurement point of that probe is considered invalid data by default.

[0076] like Figure 6 As shown, the operation steps of the coal mine flow monitoring method in step (3-3.1) are as follows:

[0077] (3-3.1.1) Measure the distance between the coal mine surface and each probe through each probe of the top detection array probe group 2, and plot the coal surface fitting curve;

[0078] (3-3.1.2) Through approximation, assume that the top detection array probe group 2 has a probes set at the same height, where a is an integer greater than 0; the arrangement length of the a probes forms the total profile cross-section with the structure of the conveyor belt 1, and the total profile cross-sectional area S is calculated using the formula S=L1*D1-(L1-L2)*(D1-D2) / 2, where S is in square meters, where: L1 is the arrangement length of each probe in the top detection array probe group 2, in meters; L2 is the straight length of the bottom of the conveyor belt 1, in meters; D1 is the height of each probe in the top detection array probe group 2 from the straight position of the bottom of the conveyor belt 1, in meters; D2 is the height of the outermost probe of the top detection array probe group 2 from the inclined side of the conveyor belt 1, in meters;

[0079] (3-3.1.3) The cross-sectional area S2 of the coal mine can be calculated using the formulas S2=S-S1 and S1=L1*(d1+d2+...+da) / a. Figure 6 The dark gray area in the image), S2 is in square meters, where S1 is the air cross-sectional area formed by the top detection array probe group 2a and the coal mine surface (…). Figure 6 (The light gray area in the image), S1 is in square meters; d1, d2, ..., da are the distances from a probes to the coal mine surface, in meters;

[0080] Assuming the conveyor belt 1 moves at a speed of V meters per second, and the coal mine cross-sectional area S2 is calculated once every β meters it moves, the number of calculations required per second is n, where n = V / β, and the unit is calculations per second; β is in meters per calculation.

[0081] The formula for calculating the instantaneous flow rate per second in a coal mine is: Fs = The unit is cubic meters per second; S2(n) is the cross-sectional area of ​​the coal mine at the nth trigger, in square meters;

[0082] The formula for calculating the total flow rate of a coal mine is: Ft = Fs * t, where Ft is in cubic meters and t is the coal mine operating time in seconds.

[0083] During the operation of conveyor belt 1, the cross-sectional area S2 of the coal mine changes constantly, therefore it is necessary to calculate the cross-sectional area of ​​the coal mine at regular intervals. For example, assuming the conveying speed of conveyor belt 1 is V = 3.5 m / s, and the calculation of the cross-sectional area S2 of the coal mine is triggered every time it moves β = 0.1 meters, the number of calculations required per second is n = 3.5 / 0.1 = 35 (times / second). Therefore, the instantaneous flow rate of the coal mine per second is Fs = .

[0084] In step (3-3.2), based on the ranging data of the reflected signals received by the left detection array probe group 4 and the right detection array probe group 5, the operation steps for automatically detecting whether there is a longitudinal tear in the conveyor belt 1 are as follows:

[0085] (3-3.2.1) The number of probes in the left detection array probe group 4 is the same as the number of probes in the right detection array probe group 5 and they are set symmetrically on the left and right sides. The ranging data of the reflected signals received by the left detection array probe group 4 and the right detection array probe group 5 are synchronously compared and analyzed.

[0086] (3-3.2.2) such as Figure 7 As shown, when there is no longitudinal tear in conveyor belt 1, the distance measured by each probe remains stable, and the distance measured by each probe is within a certain error range. All the distance measured by each probe is between the positive error reference line and the negative error reference line.

[0087] (3-3.2.3) such as Figure 8 As shown, when a longitudinal tear occurs in conveyor belt 1, within any consecutive 1-second time range, if there are more than 5 consecutive probe distance measurement points ( Figure 8 If any of the 6 probe distance measurement points are not between the positive and negative distance measurement reference lines, it will be automatically determined that there is a longitudinal tear in conveyor belt 1; or if the ultrasonic signal cannot be received due to the conveyor belt 1 deviating from the probe detection, resulting in distance measurement failure and no data display, it will be automatically determined that there is a longitudinal tear in conveyor belt 1.

[0088] Because conveyor belt 1 is depressed downwards due to the pressure from the coal mine, the ranging distance of the probes located on the side of conveyor belt 1 will change. This can easily cause the probe ranging distance to exceed the range of the positive and negative ranging error reference lines. Therefore, it is necessary to detect whether there are longitudinal tears. The rule for determining the above error reference lines is: by statistically calculating a large amount of measured probe ranging distance data under conditions without longitudinal tears, it is determined that all probe ranging distance data are between the positive and negative ranging error reference lines.

[0089] In step (3-3.3), the operation steps for automatically detecting whether there is a longitudinal tear in the conveyor belt 1 based on the ranging data of the reflected signal received by the bottom detection array probe group 3 are as follows:

[0090] (3-3.3.1) The probes of the bottom detection array probe group 3 are arranged at equal intervals along the width direction and arc shape of the conveyor belt 1;

[0091] (3-3.3.2) For example Figure 9 As shown, when there is no longitudinal tear in conveyor belt 1, at a certain moment, the distance measured by each probe remains stable, and the distance measured by each probe is within a certain error range. All the distance measured by each probe is between the positive error reference line and the negative error reference line.

[0092] (3-3.3.3) such as Figure 10 As shown, when a longitudinal tear occurs in conveyor belt 1, at a certain moment, when more than 5 of the probes in the width direction of conveyor belt 1 have a distance measurement point ( Figure 10 If 8 of the probes' distance measurement points are not between the positive and negative distance measurement reference lines, the conveyor belt 1 will be automatically determined to have a longitudinal tear. Alternatively, if more than 5 consecutive distance measurement points of a single probe are not between the positive and negative distance measurement reference lines within any consecutive 1-second time range, the conveyor belt 1 will be automatically determined to have a longitudinal tear.

[0093] In steps (3-4), when the longitudinal tearing state is abnormal, an automatic feedback signal is sent to the conveyor belt 1 system to automatically stop; when the longitudinal tearing state is normal, the conveyor belt 1 continues to transport coal.

[0094] like Figure 1-2 As shown, in step (1), each probe 11 is an array of air-coupled ultrasonic probes. The array of air-coupled ultrasonic probes in the top detection array probe group 2 are distributed along the width direction of the conveyor belt 1. The array of air-coupled ultrasonic probes in the bottom detection array probe group 3 are distributed along the width direction and arc shape of the conveyor belt 1. The array of air-coupled ultrasonic probes in the left detection array probe group 4 are distributed along the length direction of the conveyor belt 1. The array of air-coupled ultrasonic probes in the right detection array probe group 5 are distributed along the length direction of the conveyor belt 1.

[0095] The top detection array probe group 2 has 12 array air-coupled ultrasonic probes. Each array air-coupled ultrasonic probe is arranged at equal intervals along the width direction of the conveyor belt 1, and the distance between two adjacent array air-coupled ultrasonic probes is 100cm.

[0096] The bottom detection array probe group 3 has 12 array air-coupled ultrasonic probes. Each array air-coupled ultrasonic probe is arranged at equal intervals along the width direction and arc shape of the conveyor belt 1, and the distance between two adjacent array air-coupled ultrasonic probes is 100cm.

[0097] The left detection array probe group 4 and the right detection array probe group 5 each have 4 array air-coupled ultrasonic probes. Each array air-coupled ultrasonic probe is arranged at equal intervals along the length of the conveyor belt 1, and the distance between two adjacent array air-coupled ultrasonic probes is 50cm.

[0098] The array-coupled ultrasonic probe is an ultrasonic transducer. The aforementioned ultrasonic transducer uses an IP67-rated housing and operates within a temperature range of -20℃ to 85℃.

[0099] Furthermore, it should be noted that the names of the various parts of the specific embodiments described in this specification may differ. All equivalent or simple variations made to the structure, features, and principles described in this invention are included within the scope of protection of this invention. Those skilled in the art can make various modifications or additions to the described specific embodiments or use similar methods to replace them, as long as they do not deviate from the structure of this invention or exceed the scope defined in these claims, all of which should fall within the scope of protection of this invention.

Claims

1. A method for monitoring the condition of a conveyor belt based on an array-coupled ultrasonic probe, characterized in that... Includes the following steps: (1) Set a position encoder to locate and obtain the position of the conveyor belt; set a top detection array probe group, a bottom detection array probe group, a left detection array probe group and a right detection array probe group; the top detection array probe group is set above the upper surface of the conveyor belt, the bottom detection array probe group is set below the lower surface of the conveyor belt, the left detection array probe group is set on the left side of the left side of the conveyor belt, and the right detection array probe group is set on the right side of the right side of the conveyor belt, and the right detection array probe group corresponds to the left detection array probe group; the top detection array probe group, the bottom detection array probe group, the left detection array probe group and the right detection array probe group each include multiple probes; (2) The top detection array probe group emits ultrasonic signals to the upper surface of the conveyor belt and receives reflected signals to monitor the real-time coal flow on the conveyor belt; the bottom detection array probe group emits ultrasonic signals to the lower surface of the conveyor belt and receives reflected signals to monitor the longitudinal tear of the conveyor belt; the left detection array probe group emits ultrasonic signals to the left side of the conveyor belt and receives reflected signals to monitor the longitudinal tear of the conveyor belt; the right detection array probe group emits ultrasonic signals to the right side of the conveyor belt and receives reflected signals to monitor the longitudinal tear of the conveyor belt. (3) Realize synchronous acquisition of multi-channel data through the central processing unit: (3-1) Signal acquisition: The central processing unit synchronously and in real time acquires data from the top detection array probe group, bottom detection array probe group, left detection array probe group and right detection array probe group through all parallel channels, records the reflection echo time and reflection echo amplitude of each probe in real time, and calculates the probe ranging distance. The specific steps for signal acquisition are as follows: (3-1.1) Based on the reflected echo signal after the probe encounters the coal surface or conveyor belt surface, conveyor belt bottom surface, or left and right sides of the conveyor belt, measure and record the peak time of the first peak of the reflected echo signal as the reflected echo time, and measure and record the amplitude of the highest amplitude of the reflected echo signal as the reflected echo amplitude. (3-1.2) The probe ranging distance is calculated using the formula d=0.5vt based on the reflection echo time; where: d is the distance from the probe to the reflecting surface of the object being detected, in meters; v is the speed of sound in air, v is 340 m / s; t is the round-trip propagation time of the ultrasonic wave emitted by the probe, in seconds; (3-2) Data processing: As the conveyor belt runs, the position of the conveyor belt is obtained by positioning the position encoder. The distance measurement distance of the probe at different positions of the conveyor belt is continuously collected. The data of each probe distance measurement point is curve fitted using the least squares method. The distance measurement continuous recording curve of "conveyor belt position - probe distance measurement distance" of a single probe is plotted according to the reflection echo time of each probe. The distance measurement continuous recording curve also has a distance measurement positive error reference line, a distance measurement theoretical reference line and a distance measurement negative error reference line set from top to bottom. (3-3) Data Interpretation: (3-3.1) Based on the ranging data of the reflected signals received by the top detection array probe group, calculate the instantaneous flow rate per second and the total flow rate of the coal mine according to the coal mine flow monitoring method; The operational steps for coal mine flow monitoring are as follows: (3-3.1.1) Measure the distance from the coal mine surface to each probe through each probe of the top detection array probe group, and plot the coal surface fitting curve; (3-3.1.2) Through approximation, assume that the top detection array probe group has a probes set at the same height, where a is an integer greater than 0; the arrangement length of the a probes and the structure of the conveyor belt form the total profile cross-section, and the total profile cross-sectional area S is calculated by the formula S=L1*D1-(L1-L2)*(D1-D2) / 2, where S is in square meters, where: L1 is the arrangement length of each probe in the top detection array probe group, in meters; L2 is the straight length of the bottom of the conveyor belt, in meters; D1 is the height of each probe in the top detection array probe group from the straight position of the bottom of the conveyor belt, in meters; D2 is the height of the outermost probe of the top detection array probe group from the inclined side of the conveyor belt, in meters; (3-3.1.3) The cross-sectional area S2 of the coal mine is calculated using the formulas S2=S-S1 and S1=L1*(d1+d2+...+da) / a. The unit of S2 is square meters. S1 is the air cross-sectional area formed by the a probes of the top detection array and the coal mine surface. The unit of S1 is square meters. d1, d2, ..., da are the distances from the a probes to the coal mine surface, respectively, in meters. Assuming the conveyor belt's transport speed is V meters per second, and the coal mine cross-sectional area S2 is calculated once every β meters it moves, the number of calculations required per second is n, where n = V / β, and the unit is calculations per second; β is in meters per calculation. The formula for calculating the instantaneous flow rate per second in a coal mine is: Fs = The unit is cubic meters per second; S2(n) is the cross-sectional area of ​​the coal mine at the nth trigger, in square meters; The formula for calculating the total flow rate of a coal mine is: Ft = Fs * t, where Ft is in cubic meters and t is the coal mine operating time in seconds. (3-3.2) Based on the ranging data of the reflected signals received by the left and right detection array probe groups, the operation steps for automatically detecting whether there is a longitudinal tear in the conveyor belt are as follows: (3-3.2.1) The number of probes in the left detection array probe group is the same as the number of probes in the right detection array probe group and they are set symmetrically. The ranging data of the reflected signals received by the left detection array probe group and the right detection array probe group are synchronously compared and analyzed. (3-3.2.2) When the conveyor belt does not have a longitudinal tear, the distance measured by each probe remains stable and the distance measured by each probe is within a certain error range. All the distance measured by each probe is between the positive error reference line and the negative error reference line. (3-3.2.3) When a longitudinal tear occurs in the conveyor belt, if more than 5 consecutive probe distance measurement points are not between the positive and negative distance measurement reference lines within any consecutive 1-second time range, it is automatically determined that there is a longitudinal tear in the conveyor belt; or if the ultrasonic signal cannot be received due to the conveyor belt deviating from the probe detection, resulting in distance measurement failure and no data display, it is automatically determined that there is a longitudinal tear in the conveyor belt. (3-3.3) Based on the ranging data of the reflected signals received by the bottom detection array probe group, the longitudinal tear seam of the conveyor belt is automatically detected; (3-4) Output results: Output the instantaneous coal quantity, total coal quantity, and whether the longitudinal tearing status is abnormal.

2. The conveyor belt status monitoring method based on an array-coupled ultrasonic probe as described in claim 1, characterized in that: When the distance measurement point of each probe is between the positive error reference line and the negative error reference line, the distance measurement point of that probe is considered valid data; when the distance measurement point of each probe is above the positive error reference line or below the negative error reference line, the distance measurement point of that probe is considered invalid data by default.

3. The conveyor belt condition monitoring method based on an array-coupled ultrasonic probe as described in claim 1, characterized in that: In step (3-3.3), the operation steps for automatically detecting whether there is a longitudinal tear in the conveyor belt based on the ranging data of the reflected signal received by the bottom detection array probe group are as follows: (3-3.3.1) The probes of the bottom detection array probe group are arranged at equal intervals along the width direction and arc shape of the conveyor belt; (3-3.3.2) When the conveyor belt does not have a longitudinal tear, at a certain moment, the distance measured by each probe remains stable, and the distance measured by each probe is within a certain error range. All the distance measured by the probes are between the positive error reference line and the negative error reference line. (3-3.3.3) When a longitudinal tear occurs in the conveyor belt, if at a certain moment, more than 5 of the probes in the width direction of the conveyor belt have distance measurement points that are not between the positive and negative distance measurement error reference lines, then the conveyor belt is automatically determined to have a longitudinal tear; or if, within any consecutive 1-second time range, a single probe has more than 5 consecutive distance measurement points that are not between the positive and negative distance measurement error reference lines, then the conveyor belt is automatically determined to have a longitudinal tear.

4. The conveyor belt condition monitoring method based on an array-coupled ultrasonic probe as described in claim 1, characterized in that: In steps (3-4), when the longitudinal tearing condition is abnormal, an automatic feedback signal is sent to the conveyor belt system to automatically stop the machine; when the longitudinal tearing condition is normal, the conveyor belt continues to transport coal.

5. The conveyor belt status monitoring method based on an array-coupled ultrasonic probe as described in claim 1, characterized in that: In step (1), each probe is an array of air-coupled ultrasonic probes. The array of air-coupled ultrasonic probes in the top detection array probe group are distributed along the width direction of the conveyor belt. The array of air-coupled ultrasonic probes in the bottom detection array probe group are distributed along the width direction and arc shape of the conveyor belt. The array of air-coupled ultrasonic probes in the left detection array probe group are distributed along the length direction of the conveyor belt. The array of air-coupled ultrasonic probes in the right detection array probe group are distributed along the length direction of the conveyor belt.

6. The conveyor belt status monitoring method based on an array-coupled ultrasonic probe as described in claim 5, characterized in that: The top detection array probe group has 8-12 array air-coupled ultrasonic probes, and each array air-coupled ultrasonic probe is arranged at equal intervals along the width direction of the conveyor belt, with a spacing of 100-200cm between two adjacent array air-coupled ultrasonic probes. The bottom detection array probe group has 8-12 array air-coupled ultrasonic probes. Each array air-coupled ultrasonic probe is arranged at equal intervals along the width direction and arc shape of the conveyor belt, and the distance between two adjacent array air-coupled ultrasonic probes is 100-200cm. The left and right detection array probe groups each have 2-4 array air-coupled ultrasonic probes. Each array air-coupled ultrasonic probe is arranged at equal intervals along the length of the conveyor belt, and the distance between two adjacent array air-coupled ultrasonic probes is 50-200cm. The array-coupled ultrasonic probe is an ultrasonic transducer.

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