Steel wire rope core conveying belt detection device and method

Abstract

The invention relates to the technical field of conveying belt detection devices, in particular to a steel wire rope core conveying belt detection device and method.The detection device comprises a shell, a plurality of sets of detection probes are installed at the bottom of the shell, a displacement detection wheel is installed on one side of the shell, and a CPU circuit and a power circuit are integrated in the shell; the detection probe is composed of a ferrite magnetic core, two groups of receiving coils and a transmitting coil, the transmitting coil horizontally winds the ferrite magnetic core, the two groups of receiving coils vertically wind the ferrite magnetic core and are symmetrically distributed on two sides of the transmitting coil, the receiving coils are connected with the CPU circuit through a receiving circuit, and the transmitting coil is connected with the CPU circuit through a transmitting circuit. Detection is carried out by adopting a continuous sine wave excitation and biorthogonal rectangular coil receiving mode, and strong electromagnetic interference in a field environment can be effectively overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of conveyor belt detection device, in particular to a steel cord conveyor belt detection device and method. BACKGROUND

[0002] The steel cord conveyor belt has been widely used in metallurgy, mine, port and other fields due to long conveying distance, large capacity and continuous transportation. During the operation of the equipment, the steel cord conveyor belt is prone to internal damage and tearing due to the friction between the key components such as the carrier roller and the drum and the conveyor belt during the operation in the complex environment of strong impact and high load. Once the belt breaks, it will destroy the belt conveyor frame, damage the equipment, block the transportation roadway, cause long-term production stoppage and significant economic losses, and even cause casualties, with extremely serious consequences. Therefore, timely detection of the defect information of the conveyor belt is of great significance for preventing major accidents such as conveyor belt rupture and more scientifically and flexibly adjusting the inspection and maintenance strategy.

[0003] Since the steel core of the steel cord conveyor belt is located inside the belt, the defect has concealment, manual visual inspection is low in efficiency and high in cost, X-ray detection is slow in detection speed and has certain radiation damage to the human body, is not suitable for use in many occasions, and the existing probe has problems such as not obvious detection signal characteristics for deep hidden defects. In addition, in some special occasions such as coal mines, the detection equipment is required to have intrinsic safety. Under the above conditions, how to quickly, accurately and safely detect the position, type and size of the defects of the steel core in the steel cord conveyor belt has become a technical problem that has plagued people. SUMMARY

[0004] In order to solve the problems in the prior art, the present application provides a steel cord conveyor belt detection device and method, which can position the position of the defect, distinguish the type and size of the defect, avoid misjudgment caused by dense arrangement of the steel cord at the joint of the steel cord conveyor belt, and realize screening of the defects of the steel core in the steel cord conveyor belt under the premise of safety and guarantee of detection accuracy.

[0005] In order to achieve the above purpose, on the one hand, the present application provides a steel cord conveyor belt detection device, which comprises a shell; a CPU circuit and a power supply circuit are integrated in the shell; a plurality of groups of detection probes arranged in a linear array are installed at the bottom of the shell; and a displacement detection wheel is installed on one side of the shell. The detection probe comprises a ferrite core, a receiving coil, a transmitting coil, a transmitting circuit and a receiving circuit, the receiving coil and the transmitting coil are wound on the ferrite core, the receiving circuit is connected to the receiving coil, and the transmitting circuit is connected to the transmitting coil. The CPU circuit establishes a bidirectional communication link with the displacement detection wheel, the transmitting circuit, the receiving circuit and the power supply circuit respectively to realize data interaction and power supply management; the power supply circuit establishes a power supply channel with the displacement detection wheel, the transmitting circuit, the receiving circuit and the CPU circuit respectively to form a power supply loop.

[0006] Preferably, the transmitting coil is horizontally wound around the ferrite core, and the receiving coil is provided with two groups, and the two groups of receiving coils are vertically wound around the ferrite core and symmetrically distributed on both sides of the transmitting coil.

[0007] Preferably, the winding width of the receiving coil and the transmitting coil is 5 mm.

[0008] Preferably, the distance between the two groups of receiving coils in the detection probe is 10 mm.

[0009] Preferably, the ferrite core is a cuboid with a length of 80-120 mm, a width of 20-30 mm and a height of 10-20 mm.

[0010] In another aspect, the application also provides a detection method of a steel cord conveyor belt, characterized by comprising the following steps: S1, simplifying the steel cord conveyor belt into an XOY two-dimensional plane coordinate system, the X-axis direction representing the running direction of the conveyor belt, the displacement detection wheel recording the moving distance of the conveyor belt in real time and transmitting the obtained displacement data to the CPU circuit, and the Y-axis direction corresponding to the width direction of the conveyor belt, composed of N detection probes, and the detection range covering the full width of the conveyor belt; S2, any detection probe transmitting continuous signals through the transmitting coil, and the two groups of receiving coils receiving and transmitting the obtained induced voltage after differential operation and multi-stage amplification to the CPU circuit; S3, the CPU circuit performing sum and difference operations on the induced voltage after differential operation and multi-stage amplification to obtain V LMA test data and V LF test data; S4, V LMA test data is subjected to 4-order multi-Bézier wavelet transform to obtain corresponding wavelet decomposition coefficients J LMA , the maximum value among which is substituted into the formula to obtain the LMA detection result, and the LMA detection result is subjected to normalization processing with a range of -100% to 100%; S5, V LF test data is subjected to 4-order multi-Bézier wavelet transform to obtain corresponding wavelet decomposition coefficients K LF , the maximum value among which is substituted into the formula to obtain the LF detection result, and the LF detection result is subjected to normalization processing with a range of -100% to 100%; S6, the CPU circuit corresponds the normalized LMA detection result and the LF detection result with displacement data of the displacement detection wheel, positions the position of the defect on the conveying belt, and judges whether to alarm and prompt according to the set threshold value.

[0011] Preferably, the transmitting coil continuously outputs a sine wave excitation signal with a frequency of 10 kHz and a peak voltage of 5 V.

[0012] After the above technical scheme is adopted, the present application has the following beneficial effects: The detection is carried out by using continuous sine wave excitation and double-quadrature-rectangular coil receiving mode, which can effectively overcome strong electromagnetic interference in the field environment. By using the wavelet transform method, the detection precision is ensured, and by using displacement detection, the type, size and position of the core defect of the conveying belt are distinguished, so that the monitoring and screening of the steel wire core conveying belt defect are realized. At the same time, corresponding alarm output is generated according to different detection results, so as to ensure the safety of the field equipment and the continuity of the production operation. BRIEF DESCRIPTION OF DRAWINGS

[0013] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0014] Figure 1 It is a schematic diagram of the installation of the detection device; Figure 2 It is a schematic diagram of the structure of the detection probe; Figure 3 It is a structural block diagram of the detection device; Figure 4 It is a schematic diagram of the coil calculation model; Figure 5 It is a judgment basis table of the width defect LF; Figure 6 It is a judgment basis table of the depth defect LMA.

[0015] In the figure: 1-detection probe, 2-displacement detection wheel, 3-ferrite core, 4-receiving coil, 5-transmitting coil, 6-transmitting circuit, 7-receiving circuit, 8-CPU circuit, 9-power supply circuit. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical scheme and advantages of the present application more clear, the present application is further described in detail below in combination with the drawings and specific embodiments. It should be understood that the specific embodiments described herein are only configured to explain the present application and are not configured to limit the present application. The present application can be implemented without some of the specific details for those skilled in the art. The following description of the embodiments is only to provide a better understanding of the present application by showing examples of the present application.

[0017] The orientation words appearing in the following description are the directions shown in the drawings and do not limit the specific structure of the present application. In the description of the present application, it should be further explained that, unless otherwise explicitly specified and limited, the terms "mounting", "connection" should be understood broadly, for example, it can be fixed connection, or detachable connection or integrally connected; it can be directly connected or indirectly connected. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0018] The detection device is suspended above the conveying belt (steel wire core) by a fixed rod, as shown in Figure 1 The detection device includes a housing, one side of the housing is mounted with a displacement detection wheel 2, the displacement detection wheel 2 is designed in an integrated manner of a test wheel and a code disc encoder. The test wheel is placed above the conveying belt, when the conveying belt runs, the test wheel is driven to rotate synchronously by the friction force of the belt. The code disc encoder is coaxially connected with the test wheel, the rotating signal is collected in real time and converted into displacement data of the conveying belt.

[0019] A plurality of groups of detection probes 1 are arranged in a linear array at the bottom of the housing, each detection probe 1 detects a part of the conveying belt, and the position of the damaged conveying belt is determined according to the detection result of each detection probe 1, so that the detection range completely covers the full width of the conveying belt. For example, the width of the conveying belt is 1 meter, and the number of detection probes 1 is 5.

[0020] As shown in Figure 2 The detection probe 1 is composed of a box body and an iron core 3, a transmitting coil 5 and two groups of receiving coils 4 which are perpendicular to the transmitting coil 5 in the box body. The transmitting coil 5 is horizontally wound around the iron core 3, and the two groups of receiving coils 4 are vertically wound around the iron core 3 and symmetrically distributed on both sides of the transmitting coil 5.

[0021] The transmitting coil 5 is perpendicular to the receiving coil 4, so that the signals sensed by the two groups of receiving coils 4 are opposite in phase. When the environmental electromagnetic interference (such as power supply noise) is coupled to the coil in the form of common mode, the differential operation will cancel such interference and only keep the differential mode signal reflecting the damage of the steel wire core.

[0022] The ferrite core 3 is a rectangular parallelepiped with a length of 80 to 120 mm, a width of 20 to 30 mm, and a height of 10 to 20 mm. The moderate size can avoid increasing the weight of the ferrite core 3, prevent magnetic field saturation, and ensure a linear detection range.

[0023] The receiving coil 4 and the transmitting coil 5 are made of the same material, and the turn widths of the receiving coil 4 and the transmitting coil 5 are both 5 mm.

[0024] If the turns of the transmitting coil 5 are too wide, the magnetic field energy generated by it will be too dispersed, and the ferrite core 3 will not be able to effectively focus the magnetic field, reducing the excitation intensity of the wire rope core. Narrow turns require a higher current density to maintain the same ampere-turns, which may cause the coil to heat up more and may cause insulation aging or burnout with long-term use.

[0025] Wide turns of the receiving coil 4 cover a larger spatial area, but the effective magnetic conductivity area of ​​the ferrite core 3 is limited, resulting in the magnetic field signal captured by the receiving coil 4 containing more irrelevant noise (such as environmental electromagnetic interference). Narrow turns may reduce the number of turns, resulting in a lower amplitude of the induced electromotive force, requiring a higher-gain amplifier, while also amplifying the noise.

[0026] The two sets of receiving coils 4 in each detection probe 1 are spaced 10 mm apart. When a defect in the wire rope core occurs, its magnetic field disturbance propagates to the two sets of receiving coils 4 at different phases. This 10 mm spacing ensures a sufficient phase difference between the signals induced by the two coils, achieving an optimal balance between suppressing lateral interference (such as magnetic field fluctuations caused by conveyor belt vibration) and preserving the damage signal, facilitating the extraction of defect characteristics through differential circuits.

[0027] like Figure 3 As shown, the detection device adopts a highly integrated modular design. The housing integrates a CPU circuit 8 and a power supply circuit 9. Each detection probe 1 houses a built-in transmitter circuit 6 and receiver circuit 7. Independent power supply channels and bidirectional communication links enable data exchange and power management between modules, establishing an efficient and reliable wire rope core damage detection system.

[0028] The receiving circuit 7 is connected to the two sets of receiving coils 4 within the detection probe 1, while the transmitting circuit 6 is connected to the transmitting coil 5. The CPU circuit 8, as the core of the system, establishes a bidirectional communication link with the transmitting circuit 6, the receiving circuit 7, the power supply circuit 9, and the code disk encoder to achieve data exchange and power supply management. The power supply circuit 9, as the energy center of the system, establishes power supply channels with the transmitting circuit 6, the receiving circuit 7, the CPU circuit 8, and the code disk encoder, forming a power supply circuit.

[0029] The following are specific implementation methods and technical details for detecting defects in steel cord conveyor belts using the above-mentioned detection device.

[0030] The conveyor belt is simplified as an XOY two-dimensional plane coordinate system. The X-axis direction represents the running direction of the conveyor belt, and the displacement detection wheel 2 records the moving distance x of the conveyor belt in real time, with a detection accuracy of 1 meter per 1,000 pulses. The Y-axis direction corresponds to the width direction of the conveyor belt, which is composed of N detection probes 1, and the detection range covers the full width y of the conveyor belt.

[0031] The transmitting circuit 6 is composed of an AD9851 chip, a driving circuit of the AD9851 chip, and an operational amplifier. The AD9851 chip generates a digital signal through DDS, which is then converted by a DAC, low-pass filtered, and amplified by an operational amplifier to drive the transmitting coil 5 to generate a continuous sinusoidal excitation signal with a frequency of 10 kHz and a peak voltage of 5 V. The functional expression of the sinusoidal excitation signal is:

[0032] In the formula, is the excitation signal of the output coil, is the time s.

[0033] As Figure 4 shown, when the transmitting coil 5 is connected with an alternating current, an alternating magnetic field is generated around it. When the steel wire core in the conveyor belt senses the alternating magnetic field, an induced eddy current is generated inside, and a new magnetic field is also generated around it. The two receiving coils 4 obtain an induced voltage through the magnetic field generated by the steel wire core. The receiving circuit 7 performs differential operation and multi-stage amplification on the obtained induced voltage and transmits it to the CPU circuit 8, obtaining V1 and V2. The difference and sum of V1 and V2 are obtained, and V LF and V LMA are obtained.

[0034] The functional expressions of V LF and V LMA are as follows:

[0035]

[0036] In the formula, , is the induced voltage of the receiving coil, , is the difference and sum of the induced voltage, is the number of turns of the receiving coil, is the number of turns of the transmitting coil, is the relative permeability of air, is the length of the ferrite core, is the width of the ferrite core, is the distance between the ferrite core and the conveyor belt, is the angular frequency of the transmitting coil, is the current value of the transmitting coil, is time s, is the notch position function.

[0037] When the defect-free part of the steel wire core passes through the detection area of the detection probe 1, the new magnetic field generates magnetic fluxes of equal magnitude but opposite directions in the two receiving coils 4, the model is in a symmetrical structure, so the sum V LMA is 0. But if the notch is biased to one side of the receiving coil 4, it will cause the magnetic flux change of that side to be stronger, and the magnetic flux change of the other side to be weaker. Through the negative increase or positive increase of V LF , the position of the notch in the Y-axis direction is judged.

[0038] The function expression of V

[0039] In the formula, represents the length of the notch along the x-axis direction, is the projection position of the notch center, is the projection position of the center of the ferrite core.

[0040] If the center projection of the ferrite core 3 completely covers the center projection of the notch, the value of V is 1.

[0041] In a certain time, take the first 199 and the current V LMA , after taking the value, through 4-order Morlet wavelet transform (5-layer decomposition), the corresponding wavelet decomposition coefficient J LMA is obtained. Take the maximum value in J LMA , substitute it into the formula to calculate the LMA detection result at this moment, and the formula is:

[0042] The LMA test result is normalized, the range is set to -100%-100%, and after calculation, it is recorded as W LMA_n , and the function expression of W LMA_n is:

[0043] In a certain time, take the first 199 and the current V LF , after taking the value, through 4-order Morlet wavelet transform (5-layer decomposition), the corresponding wavelet decomposition coefficient K LF is obtained. Take the maximum value in K LF , substitute it into the formula to calculate the LF detection result at this moment, and the formula is:

[0044] The LMA test result is normalized, the range is set to -100%~100%, and the calculation result is recorded as W LF_n , W LF_n The function expression of W

[0045] The LMA test result W LMA_n , the LF test result W LF_n and the position P (the displacement data obtained by the displacement detection wheel 2 in a unit time) are associated, and the corresponding relationship between the test results of LMA and LF and the position at the same time can be obtained. When the conveyor belt has a defect, the system can locate the position of the defect on the conveyor belt through the recorded x position and y partition. As shown in Figure 5 and Figure 6 , whether to alarm is judged according to the set threshold. Wherein, N is the installation number of the detection probe 1.

[0046] The present application adopts continuous sine wave excitation and double-quadrature rectangular coil receiving mode for detection, which can effectively overcome strong electromagnetic interference in the field environment. The longitudinal position coordinates of the defect are obtained by the displacement detection wheel 2, the transverse position of the defect is determined according to the position of the detection probe 1, the type of the defect is determined according to the judgment rule table, and the size is reflected by the detection signal strength. By using the wavelet transform method, the type, size and position of the core defect of the conveyor belt are distinguished under the premise of ensuring the detection accuracy, and the monitoring and screening of the steel wire core conveyor belt defect are realized. At the same time, corresponding alarm output is generated according to different detection results, so as to ensure the safety of the field equipment and the continuity of the production operation.

[0047] According to the embodiments of the present application as described above, these embodiments do not describe all the details and are not limited to the specific embodiments. Obviously, many modifications and changes can be made according to the above description. The present application selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present application, so that those skilled in the art can well utilize the present application and make modifications and uses on the basis of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A steel cord conveyor belt detection device, comprising a housing; characterized in that: A CPU circuit (8) and a power supply circuit (9) are integrated inside the housing, a plurality of detection probes (1) arranged in a linear array are installed at the bottom of the housing, and a displacement detection wheel (2) is installed on one side of the housing; The detection probe (1) comprises a ferrite core (3), a receiving coil (4), a transmitting coil (5), a transmitting circuit (6) and a receiving circuit (7), wherein the receiving coil (4) and the transmitting coil (5) are wound around the ferrite core (3), the receiving circuit (7) is connected to the receiving coil (4), and the transmitting circuit (6) is connected to the transmitting coil (5); The CPU circuit (8) establishes a bidirectional communication link with the displacement detection wheel (2), the transmitting circuit (6), the receiving circuit (7) and the power supply circuit (9) respectively, thereby realizing data interaction and power supply management; the power supply circuit (9) establishes a power supply channel with the displacement detection wheel (2), the transmitting circuit (6), the receiving circuit (7) and the CPU circuit (8) respectively, thereby forming a power supply loop.

2. The steel cord conveyor belt detection device according to claim 1, characterized in that: The transmitting coil (5) is horizontally wound around the ferrite core (3), and two groups of receiving coils (4) are provided. The two groups of receiving coils (4) are vertically wound around the ferrite core (3) and are symmetrically distributed on both sides of the transmitting coil (5).

3. The steel cord conveyor belt detection device according to claim 2, characterized in that: The receiving coil (4) and the transmitting coil (5) both have a turn width of 5 mm.

4. The steel cord conveyor belt detection device according to claim 3, characterized in that: The distance between the two groups of receiving coils (4) in the detection probe (1) is 10 mm.

5. The steel cord conveyor belt detection device according to claim 4, characterized in that: The ferrite core (3) is a rectangular parallelepiped with a length of 80 to 120 mm, a width of 20 to 30 mm, and a height of 10 to 20 mm.

6. A method for detecting a steel cord conveyor belt detection device according to any one of claims 1 to 5, characterized in that: The steps include: S1. Simplify the steel cord conveyor belt into an XOY two-dimensional plane coordinate system, where the X-axis direction represents the running direction of the conveyor belt. The displacement detection wheel (2) records the moving distance of the conveyor belt in real time and transmits the obtained displacement data to the CPU circuit (8). The Y-axis direction corresponds to the width direction of the conveyor belt. It is composed of N detection probes (1) divided into zones, and the detection range covers the full width of the conveyor belt. S2, any detection probe (1) transmits a signal through the transmitting coil (5), and the two sets of receiving coils (4) receive and perform differential calculation on the obtained induced voltage, amplify it in multiple stages, and then transmit it to the CPU circuit (8); S3, CPU circuit (8) performs the sum and difference of the induced voltage after differential operation and multi-stage amplification to obtain V LMA Test data and V LF Test data; S4、V LMA The test data is transformed by the 4th order Multi-Bechie wavelet to obtain the corresponding wavelet decomposition coefficient J LMA , take the maximum value and substitute it into the formula to obtain the LMA test result, normalize the LMA test result and set the range to -100% to 100%; S5、V LF The test data is transformed by the 4th order Dobesi wavelet to obtain the corresponding wavelet decomposition coefficient K LF , take the maximum value and substitute it into the formula to obtain the LF test result, normalize the LF test result and set the range to -100% to 100%; S6, the CPU circuit (8) matches the normalized LMA detection result and LF detection result with the displacement data of the displacement detection wheel (2), locates the position of the defect on the conveyor belt, and determines whether to issue an alarm based on the set threshold.

7. The detection method of the steel cord conveyor belt detection device according to claim 6, characterized in that: The transmitting coil (5) continuously outputs a sinusoidal wave excitation signal with a frequency of 10 kHz and a peak voltage of 5V.

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