Online belt tearing monitoring method and device and conveying system

Abstract

The invention discloses a belt tearing on-line monitoring method. The method comprises the following steps that the temperature field distribution condition of the surface of a belt is obtained; and judging whether the surface of the belt is torn according to the temperature field distribution condition. The online belt tearing monitoring method is higher in timeliness, sensitivity and accuracy, less affected by the environment and better in monitoring effect, potential safety hazards can be eliminated in time, and the safety and reliability of belt conveying are effectively improved. The invention further provides belt tearing online monitoring equipment and a conveying system.

Description

Technical Field

[0001] The present invention specifically relates to a belt tearing online monitoring method, equipment and a conveying system. Background Art

[0002] The importance of belt conveyors in industrial production is self-evident, but belt tearing problems that may occur during their operation should not be ignored. Belt tearing may cause production interruptions, economic losses, and even safety accidents.

[0003] The current monitoring devices have certain limitations. For example, the monitoring is performed by the monitoring rod contacting the belt. This method may not be able to give a timely warning due to the incomplete measurement position. When the belt tear is not directly above the monitoring rod, the monitoring rod cannot give a warning in the first time. The friction between the monitoring rod and the belt also causes certain wear and tear on the belt. In addition, the corresponding additional sensors and cleaning components may make the system more complicated, increasing the difficulty of installation and debugging. Another type of monitoring method that uses a receiving tray to receive materials may not be able to effectively detect when there is less material or the belt is scratched or overlapped. In addition, the accuracy and stability of traditional detection technology in harsh environments are also challenged. For example, the sensitivity of the sensor component is easily affected by temperature and humidity, because these factors affect the propagation speed and efficiency of the wave, and the propagation effect is not good in some materials, which limits the application scope of the monitoring system; in addition, the reflective coating may gradually fail due to wear or contamination of materials, and requires regular inspection and maintenance.

[0004] It can be seen that it is difficult for the current belt conveyor to obtain the belt tearing situation in a timely and accurate manner, and the delay in this opportunity will further aggravate the problem and may cause more serious economic losses and accidents. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide an online monitoring method for belt tearing in view of the above-mentioned deficiencies in the prior art. The method has higher timeliness, sensitivity and accuracy, is less affected by the environment, has better monitoring effect, can eliminate potential safety hazards in time, and effectively improves the safety and reliability of belt conveying. The present invention also provides an online monitoring device for belt tearing and a conveying system.

[0006] The present invention provides a belt tearing online monitoring method, comprising the following steps:

[0007] Obtain the temperature field distribution on the belt surface;

[0008] Determine whether the belt surface is torn based on the temperature field distribution.

[0009] Further, judging whether tearing occurs on the belt surface according to the temperature field distribution specifically includes:

[0010] Obtain the temperature value and temperature rise value of the belt surface according to the temperature field distribution;

[0011] Determine whether the temperature value meets the first setting condition;

[0012] Determining whether the temperature rise value meets the second setting condition;

[0013] When both the first set condition and the second set condition are satisfied, it is determined that the belt surface is torn.

[0014] Furthermore, the second setting condition is that the temperature rise value per unit time is not less than the temperature rise preset value,

[0015] The temperature rise preset value ΔT is obtained by the following calculation formula:

[0016]

[0017] Among them, ΔT represents the temperature difference between the damaged part and the undamaged part after the belt is torn, ρ is the density of the belt, c is the specific heat capacity of the belt, k is the thermal conductivity of the belt, α represents the absorption rate of the belt, t is the unit time, l is the distance between the damaged part and the set undamaged part after the belt is torn, and L is the position of the damaged part after the belt is torn.

[0018] Furthermore, the first setting condition is that the temperature value is greater than the temperature preset value; the temperature preset value includes a first preset value and a second preset value, and the second preset value is greater than the first preset value;

[0019] When both the first setting condition and the second setting condition are satisfied, determining that an abnormality occurs on the belt surface specifically includes:

[0020] When the temperature value is greater than the first preset value and the second set condition is met, it is determined that an abnormality occurs on the belt surface and an early warning signal is generated;

[0021] When the temperature value is greater than the second preset value and the second set condition is met, it is determined that the belt surface is torn and an alarm signal is generated.

[0022] Furthermore, the obtaining of the temperature field distribution of the belt surface specifically includes: obtaining a sequence of infrared images of the belt surface;

[0023] The step of obtaining the temperature value and temperature rise value of the belt surface according to the temperature field distribution specifically includes:

[0024] Convert the infrared image sequence into a two-dimensional matrix, assuming that the size of the two-dimensional matrix is ​​K×MN, where row K represents the number of infrared image frames, and column MN represents the size of a single infrared image frame;

[0025] Calculate the average of each column of the two-dimensional matrix, and decentralize the data of each row of the two-dimensional matrix according to the average of each column, so as to calculate the eigenvector of the two-dimensional matrix;

[0026] The principal component in the eigenvector is selected and multiplied with the two-dimensional matrix to obtain the eigenimage, thereby processing the temperature value and temperature rise value of the belt surface.

[0027] Furthermore, when both the first set condition and the second set condition are met, it is determined that the belt surface is torn, and the method then includes the following steps: comparing the temperature value and the temperature rise value with the historical data of belt tearing, judging whether the belt surface is accurately torn based on the comparison result, and generating a stop signal after judging that the belt surface is accurately torn; and controlling the belt to stop based on the stop signal.

[0028] The present invention also provides an online monitoring device for belt tearing, comprising an infrared camera and a monitoring host, wherein the infrared camera is used to capture a sequence of infrared images of the belt surface to obtain the temperature field distribution of the belt surface; the monitoring host is electrically connected to the infrared camera to determine whether the belt surface is torn based on the temperature field distribution.

[0029] Furthermore, the infrared camera is installed on a roller below the material receiving position in the belt conveyor, located in the area between the working belt and the return belt of the belt conveyor, and the end of the infrared camera faces the working belt, so that the surface of the working belt at the material receiving position is used as a monitoring area for obtaining the temperature field distribution.

[0030] Furthermore, the infrared camera includes a camera, a hose, a fan and an air outlet device. The air outlet device is arranged along one side of the camera, and an air outlet is opened on the air outlet device. The direction of the air outlet is parallel to the camera surface. The fan is connected to the air outlet device through a hose so that the air flow is blown out through the air outlet to clean the camera surface.

[0031] Furthermore, the camera head of the infrared camera includes a germanium lens, an uncooled focal plane detector, an image signal processor, a field programmable gate array, and a digital signal processor. The germanium lens is used to obtain thermal radiation information of the belt surface through a captured image sequence. The uncooled focal plane detector is electrically connected to the germanium lens, and is used to receive thermal radiation information and convert it into an electrical signal. The image signal processor is electrically connected to the uncooled focal plane detector, and is used to process the electrical signal to generate image data. The field programmable gate array is electrically connected to the image signal processor, and is used to process the image data. The digital signal processor is electrically connected to the field programmable gate array, and is used to perform digital signal processing on the processed image data to obtain an infrared image sequence.

[0032] Furthermore, the monitoring host includes a data processing module, which is used to obtain the temperature value and temperature rise value of the belt surface according to the temperature field distribution, and to determine whether the temperature value meets the first set condition, whether the temperature rise value meets the second set condition, and when both the first set condition and the second set condition are met, determine whether the belt surface is torn.

[0033] Furthermore, the equipment also includes an alarm control unit and a control cabinet. The alarm control unit is electrically connected to the monitoring host, and is used to compare the temperature value and the temperature rise value with the historical data of belt tearing when the monitoring host determines that an abnormality has occurred on the belt surface, and to determine whether the belt surface tearing has occurred accurately based on the comparison result, and to generate a shutdown signal after determining that the belt surface tearing has occurred accurately; the control cabinet is electrically connected to the alarm control unit and the belt conveyor, respectively, and is used to control the belt conveyor to stop according to the shutdown signal.

[0034] The present invention also provides a conveying system, including a chute, a belt conveyor and the above-mentioned online belt tear monitoring device, wherein one end of the belt conveyor is arranged below the chute as a material receiving position, and the other end leads to a set position for receiving the material in the chute and conveying it to the set position, and the online belt tear monitoring device is installed at the material receiving position of the belt conveyor for monitoring whether tears occur on the belt surface.

[0035] The inventors of the present invention discovered that when the belt surface is damaged, the transmitted heat waves and reflected heat waves on the belt surface will interfere or superimpose, and then different intensities of thermal energy will be exhibited correspondingly, resulting in an uneven temperature field. Based on this, the online monitoring method for belt tearing of the present invention first obtains the temperature field distribution on the belt surface, and then determines whether the belt surface is torn according to the temperature field distribution, that is, the defects on the belt surface are evaluated and determined by analyzing the temperature field data on the belt surface.

[0036] In this monitoring method, first of all, the acquisition of temperature field distribution does not require direct contact with the belt surface, thus avoiding alarm delays caused by incomplete measurement positions and effectively avoiding the impact of friction and wear on the belt itself. And judging whether tearing occurs based on the distribution of the temperature field can effectively avoid the influence of the environment itself, and is suitable for various situations that are difficult to accurately measure. It can be seen that the overall timeliness, sensitivity and accuracy of this method are higher, it is less affected by the environment, and the monitoring effect is better. And precisely because it is timely and effective, it can eliminate safety hazards in a timely manner, effectively improve the safety and reliability of belt conveyors, and avoid serious economic losses and accidents. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 is a schematic structural diagram of an online belt tear monitoring device in Embodiment 2 of the present invention;

[0038] Figure 2 2 is a schematic diagram of the structure of an infrared camera of an online belt tear monitoring device in Embodiment 2 of the present invention;

[0039] Figure 3 Schematic diagram of the layout of infrared cameras of the belt tearing online monitoring device in Example 2 of the present invention;

[0040] Figure 4 1 is a schematic diagram of the monitoring process of the online belt tear monitoring device in Embodiment 2 of the present invention;

[0041] Figure 5 It is a schematic diagram of the general principle of the online belt tear monitoring method in Example 1 of the present invention.

[0042] In the figure: 1. infrared camera; 11. camera head; 12. hose; 13. fan; 14. air outlet device; 15. air outlet; 16. support frame assembly; 17. dust cover; 2. monitoring host; 3. alarm control unit; 31. cloud server; 32. network repeater; 4. control cabinet; 5. belt conveyor; 51. roller; 52. working belt; 53. return belt. DETAILED DESCRIPTION

[0043] The following will be combined with the accompanying drawings in the present invention to clearly and completely describe the technical solutions in the invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of the present invention.

[0044] In the description of the present invention, it should be noted that the terms "upper", "lower" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings and are only for the convenience and simplification of the description. They do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present invention.

[0045] In the description of the present invention, the terms “first”, “second” and “third” are used for descriptive purposes only and should not be understood as indicating or implying relative importance.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connect", "set", "install", "fix" and the like should be understood in a broad sense, for example, it can be a fixed connection or a detachable connection, or an integral connection; it can be a direct connection or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0047] Example 1

[0048] The belt tearing online monitoring method of this embodiment includes the following steps:

[0049] Obtain the temperature field distribution on the belt surface;

[0050] Determine whether the belt surface is torn based on the temperature field distribution.

[0051] When the belt surface is damaged, the transmitted heat waves and reflected heat waves on the belt surface will interfere or superimpose, and the corresponding heat energies will be different intensities, resulting in an uneven temperature field. Based on this, the online belt tear monitoring method of this embodiment first obtains the temperature field distribution on the belt surface, and then determines whether the belt surface is torn according to the temperature field distribution, that is, the defects on the belt surface are evaluated and determined by analyzing the temperature field data on the belt surface.

[0052] In this monitoring method, first of all, the acquisition of temperature field distribution does not require direct contact with the belt surface, thus avoiding alarm delays caused by incomplete measurement positions and effectively avoiding the impact of friction and wear on the belt itself. And judging whether tearing occurs based on the distribution of the temperature field can effectively avoid the influence of the environment itself, and is suitable for various situations that are difficult to accurately measure. It can be seen that the overall timeliness, sensitivity and accuracy of this method are higher, it is less affected by the environment, and the monitoring effect is better. And precisely because it is timely and effective, it can eliminate safety hazards in a timely manner, effectively improve the safety and reliability of belt conveyors, and avoid serious economic losses and accidents.

[0053] In this embodiment, judging whether tearing occurs on the belt surface according to the temperature field distribution specifically includes:

[0054] Obtain the temperature value and temperature rise value of the belt surface according to the temperature field distribution;

[0055] Determine whether the temperature value meets the first setting condition;

[0056] Determining whether the temperature rise value meets the second setting condition;

[0057] When both the first set condition and the second set condition are satisfied, it is determined that the belt surface is torn.

[0058] When the belt is torn, the local material damage will produce abnormally high temperature, so the temperature value is an important basis for determining the tear, and the temperature rise value is a dynamic process that can quantify the accumulation of heat. It can not only effectively compensate for the monitoring lag caused by the delay of heat conduction, but also eliminate the influence of ambient temperature fluctuations. When the absolute temperature has not yet reached the temperature that may be caused by the tear, the temperature rise value will have a steepening feature, so the early warning can be completed in advance. For this reason, the first setting condition in this embodiment can be further reduced compared to the absolute temperature caused by the real tear, so as to ensure the accuracy of the determination by judging the temperature rise value while expanding the determination range, that is, improving timeliness while avoiding missed detection and false detection.

[0059] In this embodiment, the second setting condition is that the temperature rise value per unit time is not less than the temperature rise preset value.

[0060] The temperature rise preset value ΔT is calculated by the following formula:

[0061]

[0062] Among them, ΔT represents the temperature difference between the damaged part and the undamaged part after the belt is torn, ρ is the density of the belt, c is the specific heat capacity of the belt, k is the thermal conductivity of the belt, α represents the absorption rate of the belt, e is the natural base, the approximate value is 2.71828, t is the unit time, l is the distance between the damaged part and the set undamaged part after the belt is torn, this "set undamaged part" is the undamaged part that can represent the undamaged position and serve as the temperature measurement reference, so it can also be said to be the characteristic distance between the temperature measurement point and the thermal disturbance source, and L is the position of the damaged part after the belt is torn.

[0063] It is based on the following:

[0064] Kirchhoff's law obtains the quantitative relationship between the radiation emittance and absorption amplitude of an object based on the law of thermal equilibrium and the law of heat conduction, which is expressed as:

[0065] M=αE (1)

[0066] In formula (1), M represents the radiation emission angle (radiation emittance) of the object; α represents the absorptivity of the object; and E represents the radiation illuminance. It can be seen that the ability of an object to radiate heat (radiation emittance) is proportional to its ability to absorb heat (absorptivity).

[0067] According to Planck's equation, the infrared radiation power of an object at different wavelengths at different temperatures can be obtained:

[0068]

[0069] In formula (2), C is the speed of light in vacuum, which is constant at 3×10 8m / s; h is Planck's constant, which is constant at 6.6256×10 -34 J / s; k is the Boltzmann constant (since the subsequent thermal conductivity is also labeled with this number, only k in this formula and the related symbol explanations of this formula such as C2 represents the Boltzmann constant), which is constant at 1.38054×10 -23 J / K; e is the natural base, approximate value is 2.71828; C1=2πhc 2 , λ is the wavelength, T is the absolute temperature, M bλ (λ,T) is the radiated power.

[0070] Then the total radiation emission angle of blackbody radiation is M b (λ,T) is:

[0071]

[0072] Also because dλ=C2dx(Tx 2 ), the above formula can be simplified to:

[0073]

[0074] In formula (4), is the Stefan-Boltzmann constant. In summary, the actual infrared thermal radiation law M λ (λ,T) can be expressed as:

[0075] M λ (λ,T)=∈ λT M bλ (λ,T)(5)

[0076] In formula (5), ∈ λT is the spectral emittance of the actual object, which is the spectral emittance of the belt in this embodiment.

[0077] Then when the thermal excitation source acts on the object (belt, or tape), according to Kirchhoff's law, after the object is excited, the heat of the object will diffuse and eventually reach a state of equilibrium through heat transfer. The heat absorbed by its surface is expressed as I. According to the one-dimensional Fourier conduction equation, the heat transfer process is described as:

[0078]

[0079] In equation (6), T(x,t) is the temperature of the object at time t and x coordinate; ρ is the density of the belt; c is the specific heat capacity of the belt, and k is the thermal conductivity of the belt. Solving equation (6) yields:

[0080]

[0081] Where T0 is the initial temperature of the belt, α=k / ρc is the thermal diffusivity of the belt, and when the belt surface is not damaged, its surface temperature function can be described as:

[0082]

[0083] When the belt surface is damaged, the surface temperature is different due to the difference in thermal properties between the damaged and undamaged parts. The surface temperature function of the damaged part is described as:

[0084]

[0085] Based on this, the surface temperature difference between the damaged part and the undamaged part (or, when the belt is damaged, the temperature rise after damage compared to before damage) can be described as:

[0086]

[0087] In summary, when the belt is not damaged, it can be obtained from function expression (8) that the present embodiment uses infrared camera 1 to obtain the belt surface temperature field, that is, the temperature of the belt surface is collected by the infrared thermal imager to obtain the belt surface temperature field. When the belt surface is damaged, the transmitted heat wave and the reflected heat wave on the surface will interfere or overlap. It can be obtained from function expression (9) that the belt surface will show different intensities of heat energy, resulting in an uneven temperature field on the target. It can be obtained from function expression (10) that there will be a temperature difference on the belt surface.

[0088] According to this, if Figure 5 As shown, the target radiation can be captured by the lens after being transmitted through the atmosphere. In this embodiment, the infrared camera 1 is installed on the roller 51 below the material receiving position in the belt conveyor 5, and is located in the area between the working belt 52 and the return belt 53 of the belt conveyor 5, and the end of the infrared camera 1 faces the working belt 52, so that the surface of the working belt 52 at the material receiving position is used as the monitoring area for obtaining the temperature field distribution. The belt moves relative to the infrared camera 1 with a fixed position, so that the infrared camera 1 obtains an infrared image sequence of the belt surface (the optical lens of the infrared camera obtains it and then obtains it by the uncooled focal plane detector), so as to obtain the temperature rise value (the corresponding position of the pixel) in the infrared image sequence according to the infrared image sequence that changes with time, so as to obtain the surface temperature difference between the damaged part and the undamaged part, so as to evaluate and determine the defects on the belt surface through the temperature field data analysis on the belt (specifically, the data processing module of the monitoring host 2, that is, the processing device, amplifies the signal through the preamplifier, and processes it through each signal processor, and then it can also be displayed through the display of the monitoring host 2).

[0089] The infrared camera 1 used in this embodiment is the dual-spectrum thermal imaging camera, which is installed under the roller (roller 51) and is used for non-contact temperature measurement to monitor the temperature distribution on the belt surface.

[0090] In this embodiment, the first setting condition is that the temperature value is greater than the preset temperature value;

[0091] The temperature preset value includes a first preset value and a second preset value, and the second preset value is greater than the first preset value;

[0092] When both the first setting condition and the second setting condition are satisfied, it is determined that the belt surface is abnormal, specifically including:

[0093] When the temperature value is greater than the first preset value and the second set condition is met, it is determined that an abnormality occurs on the belt surface and a warning signal is generated;

[0094] When the temperature value is greater than the second preset value and the second set condition is met, it is determined that the belt surface is torn and an alarm signal is generated.

[0095] This embodiment also performs a preliminary warning before actually generating an alarm, which can not only enable operators to pay attention to abnormal situations in advance, but also effectively reduce false alarms.

[0096] In this embodiment, a warning signal is generated when the temperature exceeds 45°C (first preset value) and the temperature rise reaches 20°C (temperature rise preset value) within 1 second, and an alarm signal is generated when the temperature exceeds 50°C (second preset value) and the temperature rise reaches 20°C (temperature rise preset value) within 1 second.

[0097] In this embodiment, obtaining the temperature field distribution on the belt surface specifically includes:

[0098] Acquire a sequence of infrared images of the belt surface;

[0099] According to the temperature field distribution, the temperature value and temperature rise value of the belt surface are obtained, including:

[0100] Convert the infrared image sequence into a two-dimensional matrix. Assume that the size of the two-dimensional matrix is ​​K×MN, where row K represents the number of infrared image frames and column MN represents the size of a single infrared image frame.

[0101] Calculate the average of each column of the two-dimensional matrix, and decentralized the data of each row of the two-dimensional matrix according to the average of each column to calculate the eigenvector of the two-dimensional matrix;

[0102] The principal component in the eigenvector (which may be temperature rise, maximum temperature, etc.) is selected and multiplied with the two-dimensional matrix to obtain a characteristic image, thereby processing the temperature value and temperature rise value of the belt surface.

[0103] That is, this embodiment uses principal component analysis (PCA) to extract features from the temperature time series (infrared image series). The PCA algorithm uses the temperature time signal X i , (i=1,……p) The specific linear combination for updating is as follows:

[0104] Y=α1X1+…+α p X p =α T X

[0105] Among them, α i , (i=1,……p) is the coefficient of the time series signal corresponding to each pixel in the thermal image (the two-dimensional matrix after the infrared image sequence is decentralized). In order to obtain the training signal (principal component) from the signal (the two-dimensional matrix after the infrared image sequence is decentralized), α i ,(i=1,……p) should satisfy the following conditions:

[0106] max α (Var(α T X))=max α (α T Var(X)α),∥α∥=1

[0107] That is α i Should represent X i The unit direction with the largest variance after projection of the covariance matrix Var(X), that is, the eigenvector corresponding to the maximum eigenvalue of the covariance matrix.

[0108] In this embodiment, when both the first setting condition and the second setting condition are satisfied, it is determined that the belt surface is torn, and then the method further includes the following steps:

[0109] Compare the temperature value and temperature rise value with the belt tearing history data, and judge whether the belt surface tearing is accurate according to the comparison result, and generate a stop signal after judging whether the belt surface tearing is accurate;

[0110] Control the belt to stop according to the stop signal.

[0111] That is, after determining the tear, the system will further combine historical data and real-time data to intelligently identify belt tear events, further improve the accuracy of monitoring results, reduce false alarms, and avoid false alarm shutdowns that cause production to be interrupted unnecessary.

[0112] The method of this embodiment can be implemented using the belt tearing online monitoring device in Example 2. In general, this embodiment is equivalent to providing a belt tearing method based on the self-cleaning infrared camera online monitoring technology, which can be used in the field of belt conveyor system monitoring technology and is suitable for real-time monitoring and early warning of belt tearing in belt conveyor systems in industries such as coal, mining, electricity, and chemical industry. This method monitors abnormally high temperature points of the belt through non-contact temperature measurement technology, and adopts a dual judgment criterion - combining temperature rise and maximum temperature value - to improve the accuracy and response speed of detection.

[0113] The abnormally high temperature points of the belt are monitored by means of non-contact temperature measurement. That is, the dual-spectrum thermal imaging camera (or infrared camera 1) installed under the roller is combined with the built-in temperature measurement algorithm of the monitoring host 2. When a sudden temperature rise of the belt is detected, a high temperature alarm signal is uploaded to the prompt control center platform (or monitoring software platform), prompting the on-site staff to deal with the problem belt in time to eliminate safety hazards.

[0114] Combined with the specific equipment in Example 2, the solution of this method uses a dual-spectrum thermal imaging camera to monitor the temperature distribution on the belt surface for the belt tearing problem. This non-contact monitoring method can not only fully cover the belt width, but also analyze the temperature data through the host's built-in algorithm, so as to timely detect and warn of potential belt tearing risks. When abnormally high temperature is detected, the system will upload the alarm information to the central control platform so that timely countermeasures can be taken.

[0115] The method steps after combining the specific equipment in Example 2 are as follows:

[0116] Step 1: Use a germanium lens to capture the thermal radiation information of the belt. The uncooled focal plane detector receives the thermal radiation and converts it into an electrical signal. The ISP (image signal processor) processes the electrical signal to generate image data. The FPGA (field programmable gate array) further processes the image data. The DSP (digital signal processor) performs digital signal processing and transmits the data (via the NET network) to the controller (monitoring host 2).

[0117] Step 2: During the abnormality detection phase, the data acquisition module in the monitoring host 2 collects the temperature monitoring data from the dual-spectrum thermal imaging camera 11, and the data processing module analyzes the data through the built-in temperature measurement algorithm, calculates the characteristic threshold, and determines whether the collected temperature data is greater than the set temperature threshold. Specifically, if the temperature data is greater than the temperature threshold (satisfies the first set condition), output P1=1, otherwise output P1=0. Determine whether the temperature rise data is greater than the temperature rise threshold (satisfies the second set condition). If the temperature rise is greater than the threshold, output P2=1, otherwise output P2=0.

[0118] Step 3: Alarm judgment stage; check the values ​​of P1 and P2. If the sum of P1+P2 is greater than or equal to 2, it means there is a serious temperature anomaly. When the built-in temperature measurement algorithm identifies the area where the temperature rises suddenly, the alarm control unit 3 will further combine historical data and real-time data to intelligently identify belt tearing events and reduce false alarms.

[0119] Step 4: linkage control stage; once the belt tearing event is confirmed, the temperature data monitored by the real-time detection module exceeds the preset threshold, the system will output the tearing alarm information and upload it to the centralized control center platform (monitoring software platform). At the same time, the monitoring software platform connects to the network repeater 32 through the modbus tcp protocol, and the network repeater 32 outputs a switch signal to the belt tearing fault receiver in the PLC control cabinet 4 according to the protocol content, realizing linkage shutdown to prevent the occurrence of tearing accidents.

[0120] Example 2

[0121] The belt tearing online monitoring device of this embodiment is as follows: Figures 1 to 3 As shown, it includes an infrared camera 1 and a monitoring host 2. The infrared camera 1 is used to capture an infrared image sequence of the belt surface to obtain the temperature field distribution of the belt surface; the monitoring host 2 is electrically connected to the infrared camera 1 and is used to determine whether the belt surface is torn according to the temperature field distribution.

[0122] When the belt is intact, the infrared camera 1 (dual-spectrum thermal imaging camera) can collect the temperature of the belt surface to obtain the temperature field of the belt surface. When the belt surface is damaged, the transmitted heat wave and the reflected heat wave on the belt surface will interfere or overlap. The belt surface will show different intensities of thermal energy, resulting in an uneven temperature field on the target and a temperature difference on the belt surface. Therefore, the defects on the belt surface can be evaluated and determined by analyzing the temperature field data on the belt.

[0123] This embodiment uses an infrared camera 1 to obtain the temperature field distribution, which does not require direct contact with the belt surface. Therefore, it can avoid the alarm delay caused by incomplete measurement positions and effectively avoid the impact of friction and wear on the belt itself. And judging whether tearing occurs based on the distribution of the temperature field can effectively avoid the influence of the environment itself, and is suitable for various situations that are difficult to accurately measure. It can be seen that the overall timeliness, sensitivity and accuracy of this method are higher, the impact of the environment is small, the monitoring effect is better, and precisely because of its timeliness and effectiveness, it can eliminate safety hazards in a timely manner, effectively improve the safety and reliability of belt conveyors, and avoid serious economic losses and accidents.

[0124] In this embodiment, Figure 3As shown, the infrared camera 1 is installed on the roller 51 below the material receiving position in the belt conveyor 5, located in the area between the working belt 52 and the return belt 53 of the belt conveyor 5, and the end of the infrared camera 1 faces the working belt 52, so that the surface of the working belt 52 at the material receiving position is used as the monitoring area for obtaining the temperature field distribution.

[0125] This layout position sets the infrared camera 1 at the material connection position where the belt is first damaged, ensuring that the damage can be reflected through the image at the first time when the belt is connected, with good timeliness. In addition, the infrared camera 1 is located in the area between the working belt 52 and the return belt 53, and does not interfere with the material drop position. It will not affect the material drop due to interference, and can effectively prevent the material from damaging the infrared camera 1 or blocking the image of the infrared camera 1, ensuring the comprehensiveness, accuracy and effectiveness of monitoring, and extending the service life of the infrared camera 1.

[0126] In this embodiment, the infrared camera 1 includes a camera 11, a hose 12, a fan 13 and an air outlet 14. The air outlet 14 is arranged along one side of the camera 11, and an air outlet 15 is opened on the air outlet 14. The direction of the air outlet 15 is parallel to the surface of the camera 11. The fan 13 is connected to the air outlet 14 through the hose 12 so that the air flow is blown out through the air outlet 15 to clean the surface of the camera 11 and prevent material impurities and dust from gradually accumulating on the surface of the camera 11 and affecting the monitoring results.

[0127] Specifically, the infrared camera 1 also includes a support frame assembly 16, and the camera 11 adopts a dual-spectrum thermal imaging camera, which is installed on the support frame assembly 16 by bolt connection; the support frame assembly 16 is installed on the groove steel below the roller of the belt conveyor 5 body (the roller is the roller 51 below the material receiving position) by bolt connection, and the position is located below the chute near the side of the cylindrical roller, and the monitoring range is the belt area below the chute (because the fall of large pieces of sharp materials in the chute may cause the belt to tear, so this position is a key monitoring area); the fan 13 can use a high-flow fan, which is fixed to the support frame assembly 16 by bolts and connected to the lens surface air outlet 15 through a rubber hose 12. In this embodiment, a timing device can also be set to connect the fan 13. The fan 13 can realize regular cleaning of the lens surface through the timing device to ensure the imaging quality. The hose 12, the timing device, the fan 13, the air outlet 15 and the air outlet 14 can also be collectively referred to as a self-cleaning device module, which is used to automatically clean the coal dust on the lens surface, and the camera self-cleaning function can be realized through the timing system.

[0128] The infrared camera 1 further comprises a dust cover 17, which is mounted on the top of the camera head 11 and is made of nickel-chromium alloy. On the one hand, it can cope with the influence of excessive dust in the mine on the sensitivity of the instrument, and on the other hand, it can extend the maintenance cycle and service life of the instrument.

[0129] In this embodiment, the camera head 11 of the infrared camera 1 includes a germanium lens, an uncooled focal plane detector, an image signal processor, a field programmable gate array, and a digital signal processor. The germanium lens is used to obtain thermal radiation information of the belt surface through a captured image sequence. The uncooled focal plane detector is electrically connected to the germanium lens, and is used to receive thermal radiation information and convert it into an electrical signal. The image signal processor is electrically connected to the uncooled focal plane detector, and is used to process the electrical signal to generate image data. The field programmable gate array is electrically connected to the image signal processor, and is used to process the image data. The digital signal processor is electrically connected to the field programmable gate array, and is used to perform digital signal processing on the processed image data to obtain an infrared image sequence.

[0130] In this embodiment, the monitoring host 2 includes a data acquisition module and a data processing module. The data acquisition module is used to transmit the data (infrared image sequence) in the dual-spectrum thermal imaging camera 11 to the monitoring host 2.

[0131] The data processing module is used to obtain the temperature value and temperature rise value of the belt surface according to the temperature field distribution, and to determine whether the temperature value meets the first setting condition, whether the temperature rise value meets the second setting condition, and when both the first setting condition and the second setting condition are met, determine whether the belt surface is torn. That is, it is used to obtain temperature data in real time, calculate the maximum temperature and temperature rise value, determine whether they exceed the threshold, and output the tear alarm information and upload it to the platform if the judgment conditions are met.

[0132] Specifically, the monitoring host 2 has a built-in temperature measurement algorithm for analyzing the image captured by the infrared camera 1 and identifying abnormally high temperature points. After obtaining the temperature value and the temperature rise value:

[0133] When the temperature value is greater than the first preset value and the second set condition is met, it is determined that an abnormality occurs on the belt surface and a warning signal is generated;

[0134] When the temperature value is greater than the second preset value and the second set condition is met, it is determined that the belt surface is torn and an alarm signal is generated.

[0135] This embodiment also performs a preliminary warning before actually generating an alarm, which can not only enable operators to pay attention to abnormal situations in advance, but also effectively reduce false alarms.

[0136] In this embodiment, a warning signal is generated when the temperature exceeds 45°C (first preset value) and the temperature rise reaches 20°C (temperature rise preset value) within 1 second, and an alarm signal is generated when the temperature exceeds 50°C (second preset value) and the temperature rise reaches 20°C (temperature rise preset value) within 1 second.

[0137] In this embodiment, the equipment also includes an alarm control unit 3 and a control cabinet 4. The alarm control unit 3 is electrically connected to the monitoring host 2, and is used to compare the temperature value and the temperature rise value with the belt tearing history data when the monitoring host 2 determines that an abnormality has occurred on the belt surface, and to determine whether the belt surface tearing has occurred accurately based on the comparison result, and to generate a shutdown signal after determining that the belt surface tearing has occurred accurately; the control cabinet 4 is electrically connected to the alarm control unit 3 and the belt conveyor 5, respectively, and is used to control the belt conveyor 5 to stop according to the shutdown signal.

[0138] Among them, the alarm control unit 3 includes a cloud server 31, a monitoring software platform, and a network repeater 32. The cloud server 3 includes an alarm upload module for uploading the target event alarm (i.e., the early warning signal and alarm signal generated by the monitoring host 2) to the monitoring software platform. The monitoring software platform is connected to the network repeater 32 through the modbus tcp protocol (a communication protocol based on Ethernet, which is the implementation of the Modbus protocol on the TCP / IP network), and the network repeater 32 outputs a switch signal (i.e., a shutdown signal) according to the content of the protocol. The switch signal is connected to the PLC control cabinet 4 of the belt conveyor 5 to complete the linkage shutdown of the belt tearing fault.

[0139] In general, this embodiment is equivalent to providing an online monitoring device based on a self-cleaning infrared camera, which includes the device components used for monitoring and the alarm determination scheme to achieve high-precision monitoring of belt tearing of the belt conveyor 5. It aims to solve the technical difficulties of belt tearing monitoring and improve the safety and reliability of the belt conveyor system. It can be used in the field of belt conveyor system monitoring technology, and is suitable for real-time monitoring and early warning of belt tearing in belt conveyor systems in coal, mining, electricity, chemical and other industries.

[0140] This solution uses non-contact temperature measurement technology to monitor abnormally high temperature points on the belt, and adopts a dual judgment criterion - combining temperature rise and maximum temperature value - to improve the accuracy and response speed of detection. Once the belt temperature is abnormal, the high temperature alarm signal will be quickly uploaded to the centralized control center platform (monitoring software platform) so that on-site staff can handle it in time and eliminate safety hazards. In addition, the equipment itself does not contact the belt and rollers, which can ensure the safe production of the equipment. Surface temperature measurement can capture the thermal hazards of the entire belt cross section, which covers a wider area than point temperature measurement.

[0141] In addition, this embodiment also has a linkage control function, which can timely stop the machine when the belt is torn, prevent the tear from further expanding, reduce material loss and equipment damage, and ensure the safety of workers. The equipment of this embodiment has a self-cleaning function, which automatically removes dust and impurities on the lens by continuous blowing, without the need for water or cleaning fluid, ensuring that the camera can maintain a clear image in various environments and enhance the continuity and accuracy of monitoring. By reducing belt tearing accidents, this embodiment not only improves production safety, reduces casualties and equipment damage, but also enhances the social image and reputation of the enterprise, while reducing production interruptions and maintenance costs, and improving production efficiency and economic benefits.

[0142] Specifically, the equipment of this embodiment can be divided into a thermal imaging monitoring part, a data processing part, and an alarm and control part. The thermal imaging monitoring part uses a dual-spectrum thermal imaging camera installed under the roller for non-contact temperature measurement to monitor the temperature distribution on the belt surface; the data processing part is implemented by a monitoring host (or controller) with a built-in temperature measurement algorithm to analyze the images captured by the thermal imaging camera and identify abnormal high temperature points; the alarm and control part (alarm control unit) can use an alarm system and a communication module. When a sudden temperature rise is detected, a high temperature alarm signal is uploaded to the centralized control center platform and a linkage shutdown is triggered.

[0143] like Figure 4 As shown, the usage steps are as follows:

[0144] Step 1: Use a germanium lens to capture the thermal radiation information of the belt. The uncooled focal plane detector receives the thermal radiation and converts it into an electrical signal. The ISP (image signal processor) processes the electrical signal to generate image data. The FPGA (field programmable gate array) further processes the image data. The DSP (digital signal processor) performs digital signal processing and transmits the data (via the NET network) to the controller (monitoring host 2).

[0145] Step 2: During the abnormality detection phase, the data acquisition module in the monitoring host 2 collects the temperature monitoring data from the dual-spectrum thermal imaging camera 11, and the data processing module analyzes the data through the built-in temperature measurement algorithm, calculates the characteristic threshold, and determines whether the collected temperature data is greater than the set temperature threshold. Specifically, if the temperature data is greater than the temperature threshold (satisfies the first set condition), output P1=1, otherwise output P1=0. Determine whether the temperature rise data is greater than the temperature rise threshold (satisfies the second set condition). If the temperature rise is greater than the threshold, output P2=1, otherwise output P2=0.

[0146] Step 3: Alarm judgment stage; check the values ​​of P1 and P2. If the sum of P1+P2 is greater than or equal to 2, it means there is a serious temperature anomaly. When the built-in temperature measurement algorithm identifies the area where the temperature rises suddenly, the alarm control unit 3 will further combine historical data and real-time data to intelligently identify belt tearing events and reduce false alarms.

[0147] Step 4: linkage control stage; once the belt tearing event is confirmed, the temperature data monitored by the real-time detection module exceeds the preset threshold, the system will output the tearing alarm information and upload it to the centralized control center platform (monitoring software platform). At the same time, the monitoring software platform connects to the network repeater 32 through the modbus tcp protocol, and the network repeater 32 outputs a switch signal to the belt tearing fault receiver in the PLC control cabinet 4 according to the protocol content, realizing linkage shutdown to prevent the occurrence of tearing accidents.

[0148] The device of this embodiment has the following beneficial effects:

[0149] 1. The monitoring range covers all points on the belt (where the material connection position has a high risk of tearing), and can achieve continuous monitoring of any point, ensuring that the status is visible in real time and responding quickly to abnormal situations.

[0150] 2. Stable long-distance signal transmission and control solves the problems of electromagnetic interference, signal instability, weak anti-interference ability and insufficient reliability existing in traditional tear monitoring devices.

[0151] Example 3

[0152] The conveying system of this embodiment includes a chute, a belt conveyor 5 and the online belt tear monitoring device in Example 2. One end of the belt conveyor 5 is arranged below the chute as a material receiving position, and the other end leads to a set position for receiving the material in the chute and conveying it to the set position. The online belt tear monitoring device is installed at the material receiving position of the belt conveyor 5 to monitor whether tears occur on the belt surface.

[0153] It is to be understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of the present invention, but the present invention is not limited thereto. For those of ordinary skill in the art, various modifications and improvements can be made without departing from the spirit and essence of the present invention, and these modifications and improvements are also considered to be within the scope of protection of the present invention.

Claims

1. A belt tearing online monitoring method, characterized in that: The following steps are involved: Obtain the temperature field distribution on the belt surface; Determine whether the belt surface is torn based on the temperature field distribution.

2. The belt tearing online monitoring method according to claim 1 is characterized in that: The step of judging whether tearing occurs on the belt surface according to the temperature field distribution specifically includes: Obtain the temperature value and temperature rise value of the belt surface according to the temperature field distribution; Determine whether the temperature value meets the first setting condition; Determining whether the temperature rise value meets the second setting condition; When both the first set condition and the second set condition are satisfied, it is determined that the belt surface is torn.

3. The belt tearing online monitoring method according to claim 2 is characterized in that: The second setting condition is that the temperature rise value per unit time is not less than the temperature rise preset value, The temperature rise preset value ΔT is obtained by the following calculation formula: Among them, ΔT represents the temperature difference between the damaged part and the undamaged part after the belt is torn, ρ is the density of the belt, c is the specific heat capacity of the belt, k is the thermal conductivity of the belt, α represents the absorption rate of the belt, t is the unit time, l is the distance between the damaged part and the set undamaged part after the belt is torn, and L is the position of the damaged part after the belt is torn.

4. The belt tearing online monitoring method according to claim 2 is characterized in that: The first setting condition is that the temperature value is greater than the temperature preset value; The temperature preset value includes a first preset value and a second preset value, and the second preset value is greater than the first preset value; When both the first setting condition and the second setting condition are satisfied, determining that an abnormality occurs on the belt surface specifically includes: When the temperature value is greater than the first preset value and the second set condition is met, it is determined that an abnormality occurs on the belt surface and an early warning signal is generated; When the temperature value is greater than the second preset value and the second set condition is met, it is determined that the belt surface is torn and an alarm signal is generated.

5. The belt tearing online monitoring method according to claim 2, characterized in that: The obtaining of the temperature field distribution on the belt surface specifically includes: Acquire a sequence of infrared images of the belt surface; The step of obtaining the temperature value and temperature rise value of the belt surface according to the temperature field distribution specifically includes: Convert the infrared image sequence into a two-dimensional matrix, assuming that the size of the two-dimensional matrix is ​​K×MN, where row K represents the number of infrared image frames, and column MN represents the size of a single infrared image frame; Calculate the average of each column of the two-dimensional matrix, and decentralize the data of each row of the two-dimensional matrix according to the average of each column, so as to calculate the eigenvector of the two-dimensional matrix; The principal component in the eigenvector is selected and multiplied with the two-dimensional matrix to obtain the eigenimage, thereby processing the temperature value and temperature rise value of the belt surface.

6. The belt tearing online monitoring method according to claim 2, characterized in that: When both the first set condition and the second set condition are satisfied, it is determined that the belt surface is torn, and then the method further comprises the following steps: Compare the temperature value and temperature rise value with the belt tearing history data, and judge whether the belt surface tearing is accurate according to the comparison result, and generate a stop signal after judging whether the belt surface tearing is accurate; Control the belt to stop according to the stop signal.

7. An online monitoring device for belt tearing, characterized in that: It includes an infrared camera (1) and a monitoring host (2), The infrared camera (1) is used to capture a sequence of infrared images of the belt surface to obtain the temperature field distribution of the belt surface; The monitoring host (2) is electrically connected to the infrared camera (1) and is used to determine whether tearing occurs on the belt surface based on the temperature field distribution.

8. The belt tearing online monitoring device according to claim 7 is characterized by: The infrared camera (1) is installed on a roller (51) below the material receiving position in the belt conveyor (5), and is located in the area between the working belt (52) and the return belt (53) of the belt conveyor (5). Furthermore, the end of the infrared camera (1) faces the working belt (52), so that the surface of the working belt (52) at the material receiving position is used as a monitoring area for obtaining the temperature field distribution.

9. The belt tearing online monitoring device according to claim 7, characterized in that: The infrared camera (1) comprises a camera head (11), a hose (12), a fan (13) and an air outlet device (14). The air outlet device (14) is arranged along one side of the camera (11), and an air outlet (15) is provided on the air outlet device (14), and the direction of the air outlet (15) is parallel to the surface of the camera (11). The fan (13) is connected to the air outlet device (14) through a hose (12) so that airflow is blown out through an air outlet (15) to clean the surface of the camera (11).

10. The belt tearing online monitoring device according to claim 7, characterized in that: The camera head (11) of the infrared camera (1) comprises a germanium lens, an uncooled focal plane detector, an image signal processor, a field programmable gate array, and a digital signal processor. The germanium lens is used to obtain the thermal radiation information of the belt surface through the captured image sequence. The uncooled focal plane detector is electrically connected to the germanium lens to receive thermal radiation information and convert it into electrical signals. The image signal processor is electrically connected to the uncooled focal plane detector and is used to process the electrical signal to generate image data. The field programmable gate array is electrically connected to the image signal processor for processing the image data. The digital signal processor is electrically connected to the field programmable gate array and is used for performing digital signal processing on the processed image data to obtain an infrared image sequence.

11. The belt tearing online monitoring device according to claim 7, characterized in that: The monitoring host (2) comprises a data processing module, which is used to obtain the temperature value and temperature rise value of the belt surface according to the temperature field distribution, and to determine whether the temperature value satisfies a first set condition, whether the temperature rise value satisfies a second set condition, and, when both the first set condition and the second set condition are met, to determine whether the belt surface is torn.

12. The belt tearing online monitoring device according to claim 11, characterized in that: It also includes an alarm control unit (3) and a control cabinet (4), The alarm control unit (3) is electrically connected to the monitoring host (2) and is used to compare the temperature value and the temperature rise value with the belt tearing history data when the monitoring host (2) determines that the belt surface is abnormal, and to determine whether the belt surface is accurately torn according to the comparison result, and to generate a stop signal after determining that the belt surface is accurately torn; The control cabinet (4) is electrically connected to the alarm control unit (3) and the belt conveyor (5) respectively, and is used to control the belt conveyor (5) to stop according to the stop signal.

13. A conveying system, characterized in that: It comprises a chute, a belt conveyor (5) and an online belt tear monitoring device according to any one of claims 7 to 12, One end of the belt conveyor (5) is arranged below the chute as a material receiving position, and the other end leads to a set position for receiving the material in the chute and conveying it to the set position. The belt tearing online monitoring device is installed at the material receiving position of the belt conveyor (5) and is used to monitor whether tearing occurs on the belt surface.

Images