A method and system for detecting cracks in cooling water channels of coal mining machines

Abstract

The present invention discloses a method and system for detecting cracks in cooling water channels of coal mining machines. Acoustic emission sensors are arranged on the surface of cooling water channels inside the electric control box of the coal mining machine. Every four acoustic emission sensors are arranged into an acoustic emission sensor group of a Z-shaped sensor array. The acoustic emission sensors detect acoustic emission signals generated by crack expansion in the cooling water channels of the coal mining machine. A water channel crack location positioning model of the Z-shaped sensor array is constructed according to the acoustic emission signals detected by the acoustic emission sensors and the positions of the acoustic emission sensor groups of the Z-shaped sensor array corresponding to the acoustic emission sensors that detect the acoustic emission signals, thereby detecting the crack locations of the cooling water channels of the coal mining machine. The present invention can not only locate the crack locations of the water channels, but also dynamically monitor the crack conditions of the water channels for a long time. Moreover, the present invention has small size, flexible installation, and real-time passive detection characteristics, and can provide timely maintenance and fault warning for the coal mining machine.

Description

Technical Field

[0001] The invention relates to a method and a system for detecting cracks in a cooling water channel of a coal mining machine, belonging to the technical field of real-time monitoring of coal mining machines. Background Art

[0002] Coal is a basic resource and important fuel in my country, and plays a vital role in energy supply and security. In recent years, with the continuous improvement of the automation level of comprehensive mining equipment, coal mining efficiency has been significantly increased. As one of the most important comprehensive mining equipment, the working performance of the coal mining machine directly affects the total amount of coal mining and is closely related to the stability of energy supply. Based on the strategic needs of energy supply, the coal mining machine is developing in the direction of high power and small size, which also leads to serious heating of the components in the electrical control box of the coal mining machine. The bottom plate cooling water channel is usually used for heat dissipation and cooling. However, in the actual working process, due to the poor operating conditions of the coal mining machine, it often faces strong vibration environments such as cutting gangue and faults. Therefore, the water channel may rupture after a long time, which will affect the heat dissipation and work efficiency of the coal mining machine, and even cause damage to key equipment such as inverters and traction transformers. Therefore, it is very necessary to monitor the status of the cooling water channel in a timely and effective manner to ensure the safe and stable operation of the coal mining machine.

[0003] At present, handheld ultrasonic flaw detectors are usually used to detect the cooling water channels of the coal mining machine electrical control box. However, this method can only be performed before installation. Since the equipment actually operating underground has already installed electrical components, there is a lack of sufficient space and conditions for detection, and it is impossible to achieve real-time monitoring and communication with the coal mining machine control system. In addition, this solution can only detect water channel failures, but cannot accurately determine the fault location. The water channel still needs to be checked one by one later, and the cracks are usually small and difficult to detect with the naked eye, which seriously affects efficiency. Summary of the invention

[0004] Purpose of the invention: In order to overcome the deficiencies in the prior art, the present invention provides a method for detecting cracks in the cooling water channel of a coal mining machine. Acoustic emission sensors are arranged on the surface of the water channel, and sound source positioning technology is used to determine whether the water channel is cracked and the specific location of the crack, thereby realizing airborne online monitoring of the water channel status, so as to carry out maintenance work in a timely manner and ensure the efficient operation of the coal mining machine.

[0005] Technical solution: To achieve the above purpose, the technical solution adopted by the present invention is:

[0006] A method for detecting cracks in a cooling water channel of a coal mining machine comprises the following steps:

[0007] Step 1, arrange acoustic emission sensors on the surface of the cooling water channel of the coal mining machine, and every 4 acoustic emission sensors are arranged into an acoustic emission sensor group of a Z-shaped sensor array, wherein the 4 acoustic emission sensors in each acoustic emission sensor group are acoustic emission sensor 1, acoustic emission sensor 2, acoustic emission sensor 3, and acoustic emission sensor 4, respectively, acoustic emission sensor 1 and acoustic emission sensor 2 are arranged in one row, and acoustic emission sensor 3 and acoustic emission sensor 4 are arranged in another row, and the ordinates of acoustic emission sensor 1 and acoustic emission sensor 2 are the same, the ordinates of acoustic emission sensor 3 and acoustic emission sensor 4 are the same, the abscissas of acoustic emission sensor 2 and acoustic emission sensor 3 are the same, and the ordinates of acoustic emission sensor 2 and acoustic emission sensor 3 are different.

[0008] Step 2: The acoustic emission sensor detects the acoustic emission signal generated by the crack propagation in the cooling water channel of the coal mining machine.

[0009] Step 3, constructing a water channel crack position positioning model of the Z-shaped sensor array according to the acoustic emission signal detected by the acoustic emission sensor and the position of the acoustic emission sensor group of the Z-shaped sensor array corresponding to the acoustic emission sensor that detected the acoustic emission signal, and then obtaining the detected crack position of the coal mining machine cooling water channel.

[0010] Preferably: the water channel crack location positioning model of the Z-shaped sensor array is as follows:

[0011]

[0012] Among them, x p is the horizontal coordinate of the damage source P, y p is the ordinate of the damage source P, y2 is the ordinate of the acoustic emission sensor two, x2 is the abscissa of the acoustic emission sensor two, y3 is the ordinate of the acoustic emission sensor three, x3 is the abscissa of the acoustic emission sensor three, t1 is the time when the acoustic emission sensor one detects the acoustic emission signal, t2 is the time when the acoustic emission sensor two detects the acoustic emission signal, t3 is the time when the acoustic emission sensor three detects the acoustic emission signal, and t4 is the time when the acoustic emission sensor four detects the acoustic emission signal.

[0013] Preferably: the method for constructing the waterway crack location positioning model of the Z-shaped sensor array is as follows:

[0014] Step 31, the acoustic emission sensor 1 S1, the acoustic emission sensor 2 S2, the acoustic emission sensor 3 S3, and the acoustic emission sensor 4 S4 in each group of acoustic emission sensors are arranged in a Z-shaped sensor array, and the coordinates of the acoustic emission sensor 1 S1, the acoustic emission sensor 2 S2, the acoustic emission sensor 3 S3, and the acoustic emission sensor 4 S4 are (x1, y1), (x2, y2), (x3, y3), and (x4, y4), respectively. The distance between the acoustic emission sensor 1 S1 and the acoustic emission sensor 2 S2, the distance between the acoustic emission sensor 2 S2 and the acoustic emission sensor 3 S3, and the distance between the acoustic emission sensor 3 S3 and the acoustic emission sensor 4 S4 are all d.

[0015] Step 32, consider the acoustic emission sensor 1 S1, the acoustic emission sensor 2 S2, and the acoustic emission sensor 3 S3 as a sensor system, and the relationship between the damage source P and the acoustic emission sensor 2 S2 is:

[0016]

[0017] The time difference between the damage source P reaching S1 and S2 is Δt 21 =t1-t2, the time difference from the damage source P to S2 and S3 is Δt 23 =t3-t2, then:

[0018]

[0019]

[0020] get:

[0021]

[0022] Then we get:

[0023]

[0024] Wherein, α is the angle between the damage source P and the acoustic emission sensor S2 in the horizontal direction.

[0025] Step 33, consider the acoustic emission sensor 2 S2, the acoustic emission sensor 3 S3, and the acoustic emission sensor 4 S4 as a sensor system, and similarly obtain:

[0026]

[0027] Among them, β is the horizontal angle between the damage source P and the acoustic emission sensor S3, and the time difference between the damage source P reaching S2 and S3 is Δt 32 =t3-t2, the time difference between the damage source P reaching the sensors S4 and S3 is Δt 34 =t4-t3.

[0028] Step 34: According to the formulas obtained in steps 32 and 33, a water channel crack location positioning model of the Z-shaped sensor array is obtained, and then the position of the damage source P (x P ,y P ), that is, to detect the crack position of the cooling water channel of the coal mining machine.

[0029] Preferably: the acoustic emission signal detected by the acoustic emission sensor is amplified, processed and analyzed.

[0030] Preferably, the acoustic emission signal detected by the acoustic emission sensor is converted into an electrical signal.

[0031] A detection system based on the above-mentioned coal mining machine cooling water channel crack detection method includes an acoustic emission sensor unit, a signal acquisition unit, and an industrial computer. The acoustic emission sensor unit includes more than two acoustic emission sensor groups, and the acoustic emission sensor group includes 4 acoustic emission sensors. The 4 acoustic emission sensors are arranged on the surface of the coal mining machine cooling water channel to form a Z-shaped sensor array. The acoustic emission sensor is used to capture the acoustic emission signal generated by the water channel crack. The signal acquisition unit is used to collect the acoustic emission signal captured by the acoustic emission sensor and transmit it to the industrial computer. The industrial computer obtains the water channel crack position according to the acoustic emission signal transmitted by the signal acquisition unit and the position of the acoustic emission sensor of the corresponding acoustic emission sensor group.

[0032] Preferably: the acoustic emission sensor is arranged on the surface of the water channel of the electrical control box of the coal mining machine through a coupling agent.

[0033] Preferably, the industrial computer sends the obtained water channel crack position to the coal mining machine control system, and the coal mining machine control system displays the water channel crack position.

[0034] Preferably, the bottom plates of the acoustic emission sensor unit and the signal acquisition unit are copper plates.

[0035] Compared with the prior art, the present invention has the following beneficial effects:

[0036] The present invention can not only locate the position of water channel cracks, but also dynamically monitor the water channel cracking situation over a long period of time. It also has small size, flexible installation and passive detection characteristics, and can provide timely maintenance and fault warning for the coal mining machine. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 Schematic diagram of the Z-type sensor array layout.

[0038] Figure 2 Schematic diagram of cooling water channel and sensor layout.

[0039] Figure 3 This is a schematic diagram of the crack detection system for the cooling water channel of a coal mining machine.

[0040] Among them, 1 is an industrial computer, 2 is a cooling water channel, and 3 is an acoustic emission sensor. DETAILED DESCRIPTION

[0041] The present invention is further explained below in conjunction with the accompanying drawings and specific embodiments. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention. After reading the present invention, various equivalent forms of modifications to the present invention by those skilled in the art all fall within the scope defined by the claims attached to this application.

[0042] At present, ultrasonic flaw detectors are usually used to detect cracks in cooling water channels. However, this method can only be performed before the equipment is installed. Due to the complex space of underground equipment, there are usually insufficient conditions for effective detection. For this reason, this embodiment provides a method for detecting cracks in cooling water channels of coal mining machines. By reasonably arranging an acoustic emission sensor array on the upper surface of the water channel inside the electrical control box, the location of the water channel crack is detected using the principle of sound source positioning technology. The core idea is that when the cooling water channel cracks and generates an acoustic emission signal, the arrival time of the signal received by the sensor is different due to the different distances between each sensor and the crack location. Therefore, according to the time it takes for the acoustic emission signal at the water channel crack to reach each sensor, combined with the positional relationship between the sensor array and the damage source, the ratio of the time difference is calculated to obtain the positioning angle and solve it, and finally the location of the water channel crack is determined, such as Figure 1 As shown, the following steps are included:

[0043] Step 1, such as Figure 2 As shown, acoustic emission sensors are arranged on the surface of the cooling water channel of the coal mining machine, and every 4 acoustic emission sensors are arranged into an acoustic emission sensor group of a Z-shaped sensor array, wherein the 4 acoustic emission sensors in each acoustic emission sensor group are acoustic emission sensor one S1, acoustic emission sensor two S2, acoustic emission sensor three S3, and acoustic emission sensor four S4, respectively. Acoustic emission sensor one S1 and acoustic emission sensor two S2 are arranged in one row, and acoustic emission sensor three S3 and acoustic emission sensor four S4 are arranged in another row, and the ordinates of acoustic emission sensor one S1 and acoustic emission sensor two S2 are the same, the ordinates of acoustic emission sensor three S3 and acoustic emission sensor four S4 are the same, the abscissas of acoustic emission sensor two S2 and acoustic emission sensor three S3 are the same, and the ordinates of acoustic emission sensor two S2 and acoustic emission sensor three S3 are different. The arrangement of the sensors is as shown in FIG. Figure 2As shown in the figure, this is a top view of the cooling water channel. The bottom plate of the electrical component is generally made of aluminum plate with good heat dissipation, and the layout range of the water channel is based on the size of the component bottom plate. In order to effectively monitor the cracking of the cooling water channel, a "Z"-shaped sensor array is arranged on the surface of the water channel. This layout can cover the surface area of ​​the water channel to the maximum extent, and through the coordinated work of multiple sensors, the acoustic emission signal generated by the cracking of the water channel can be effectively captured. Through this arrangement, the sensitivity and accuracy of the detection can be improved, while reducing the possibility of missed detection.

[0044] Step 2: The acoustic emission sensor detects the acoustic emission signal generated by the crack propagation in the cooling water channel of the coal mining machine. When a crack occurs in the water channel, the sensor receives the acoustic emission signal generated by the crack propagation and converts the detected vibration signal into an electrical signal. Conversely, the location of the water channel crack can be obtained by amplifying, processing, analyzing, and other operations on the received signal of the sensor.

[0045] Step 3, constructing a water channel crack position positioning model of the Z-shaped sensor array according to the acoustic emission signal detected by the acoustic emission sensor and the position of the acoustic emission sensor group of the Z-shaped sensor array corresponding to the acoustic emission sensor that detected the acoustic emission signal, and then obtaining the detected crack position of the coal mining machine cooling water channel.

[0046] Method for constructing a water channel crack location positioning model of the Z-shaped sensor array:

[0047] Step 31, the acoustic emission sensor 1 S1, the acoustic emission sensor 2 S2, the acoustic emission sensor 3 S3, and the acoustic emission sensor 4 S4 in each group of acoustic emission sensors are arranged in a Z-shaped sensor array, and the coordinates of the acoustic emission sensor 1 S1, the acoustic emission sensor 2 S2, the acoustic emission sensor 3 S3, and the acoustic emission sensor 4 S4 are (x1, y1), (x2, y2), (x3, y3), and (x4, y4), respectively. The distance between the acoustic emission sensor 1 S1 and the acoustic emission sensor 2 S2, the distance between the acoustic emission sensor 2 S2 and the acoustic emission sensor 3 S3, and the distance between the acoustic emission sensor 3 S3 and the acoustic emission sensor 4 S4 are all d.

[0048] Step 32, consider the acoustic emission sensor 1 S1, the acoustic emission sensor 2 S2, and the acoustic emission sensor 3 S3 as a sensor system, and the relationship between the damage source P and the acoustic emission sensor 2 S2 is:

[0049]

[0050] The time difference between the damage source P reaching S1 and S2 is Δt 21 =t1-t2, the time difference from the damage source P to S2 and S3 is Δt 23 =t3-t2, then:

[0051]

[0052] v(α) is the speed of wave propagation. If the structure is isotropic, v(α) is a constant. If the structure is anisotropic, v(α) varies with α. From equations (2) and (3), we can get:

[0053]

[0054] From formula (2), we get:

[0055]

[0056] Transform formula (5) to obtain:

[0057]

[0058] You can get:

[0059]

[0060] Wherein, α is the angle between the damage source P and the acoustic emission sensor S2 in the horizontal direction.

[0061] Step 33, the "Z" type sensor can be regarded as two groups of "L" type sensors overlapped, and the acoustic emission sensor 2 S2, the acoustic emission sensor 3 S3, and the acoustic emission sensor 4 S4 are regarded as a group of "L" type arrays as a sensor system. Similarly, the following is obtained:

[0062]

[0063] Among them, β is the horizontal angle between the damage source P and the acoustic emission sensor S3, and the time difference between the damage source P reaching S2 and S3 is Δt 32 =t3-t2, the time difference between the damage source P reaching the sensors S4 and S3 is Δt 34 =t4-t3.

[0064] Step 34: According to the formulas obtained in steps 32 and 33, a water channel crack location positioning model of the Z-shaped sensor array is obtained, and then the position of the damage source P (x P ,y P ), that is, to detect the crack position of the cooling water channel of the coal mining machine.

[0065] The water channel crack location positioning model of the Z-shaped sensor array is as follows:

[0066]

[0067] Among them, x p is the horizontal coordinate of the damage source P, y pis the ordinate of the damage source P, y2 is the ordinate of the acoustic emission sensor 2, x2 is the abscissa of the acoustic emission sensor 2, y3 is the ordinate of the acoustic emission sensor 3, x3 is the abscissa of the acoustic emission sensor 3, t1 is the time when the acoustic emission sensor 1 detects the acoustic emission signal, t2 is the time when the acoustic emission sensor 2 detects the acoustic emission signal, t3 is the time when the acoustic emission sensor 3 detects the acoustic emission signal, and t4 is the time when the acoustic emission sensor 4 detects the acoustic emission signal. Solving equation (9) yields the position of the unique damage source P (x P ,y P ), that is, the intersection of two straight lines with S2 and S3 as the origin and angles α and β, respectively. This point is the predicted damage source coordinate, that is, the crack position of the cooling water channel of the coal mining machine

[0068] In another embodiment, a detection system based on the above-mentioned coal mining machine cooling water channel crack detection method is provided, such as Figure 3 As shown, it includes an acoustic emission sensor unit, a signal acquisition unit, and an industrial computer. The acoustic emission sensor unit includes more than two acoustic emission sensor groups. The acoustic emission sensor group includes four acoustic emission sensors. The four acoustic emission sensors are arranged on the surface of the cooling water channel of the coal mining machine to form a Z-shaped sensor array. The acoustic emission sensor is used to capture the acoustic emission signal generated by the cracking of the water channel. The signal acquisition unit is used to collect the acoustic emission signal captured by the acoustic emission sensor and transmit it to the industrial computer. The industrial computer obtains the cracking position of the water channel according to the acoustic emission signal transmitted by the signal acquisition unit and the position of the acoustic emission sensor of the corresponding acoustic emission sensor group. The industrial computer sends the obtained water channel cracking position to the coal mining machine control system, and the coal mining machine control system displays the water channel cracking position.

[0069] In order to reduce the interference of other factors, the acoustic emission sensor is arranged on the surface of the waterway using coupling agent to improve the accuracy of signal acquisition.

[0070] The signal captured by the sensor is transmitted to the industrial computer through the signal acquisition device. After corresponding calculation and analysis, the crack position is obtained and displayed on the coal mining machine control system, so that the staff can understand the crack situation of the waterway in a timely and intuitive manner and take corresponding measures to protect it in time.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for detecting cracks in a cooling water channel of a coal mining machine, characterized in that: The following steps are involved: Step 1, arranging acoustic emission sensors on the surface of the cooling water channel of the coal mining machine, and arranging every 4 acoustic emission sensors into an acoustic emission sensor group of a Z-shaped sensor array, wherein the 4 acoustic emission sensors in each acoustic emission sensor group are acoustic emission sensor 1, acoustic emission sensor 2, acoustic emission sensor 3, and acoustic emission sensor 4, respectively, acoustic emission sensor 1 and acoustic emission sensor 2 are arranged in one row, and acoustic emission sensor 3 and acoustic emission sensor 4 are arranged in another row, and the ordinates of acoustic emission sensor 1 and acoustic emission sensor 2 are the same, the ordinates of acoustic emission sensor 3 and acoustic emission sensor 4 are the same, the abscissas of acoustic emission sensor 2 and acoustic emission sensor 3 are the same, and the ordinates of acoustic emission sensor 2 and acoustic emission sensor 3 are different; Step 2, an acoustic emission sensor detects an acoustic emission signal generated by crack propagation in a cooling water channel of a coal mining machine; Step 3, constructing a water channel crack position positioning model of the Z-shaped sensor array according to the acoustic emission signal detected by the acoustic emission sensor and the position of the acoustic emission sensor group of the Z-shaped sensor array corresponding to the acoustic emission sensor that detected the acoustic emission signal, and then obtaining the detected crack position of the coal mining machine cooling water channel.

2. The method for detecting cracks in cooling water channels of a coal mining machine according to claim 1, characterized in that: The water channel crack location positioning model of the Z-shaped sensor array is as follows: Among them, x p is the horizontal coordinate of the damage source P, y p is the ordinate of the damage source P, y2 is the ordinate of the acoustic emission sensor two, x2 is the abscissa of the acoustic emission sensor two, y3 is the ordinate of the acoustic emission sensor three, x3 is the abscissa of the acoustic emission sensor three, t1 is the time when the acoustic emission sensor one detects the acoustic emission signal, t2 is the time when the acoustic emission sensor two detects the acoustic emission signal, t3 is the time when the acoustic emission sensor three detects the acoustic emission signal, and t4 is the time when the acoustic emission sensor four detects the acoustic emission signal.

3. The method for detecting cracks in cooling water channels of a coal mining machine according to claim 2, characterized in that: Method for constructing a water channel crack location positioning model of the Z-shaped sensor array: Step 31, the acoustic emission sensor 1 S1, the acoustic emission sensor 2 S2, the acoustic emission sensor 3 S3, and the acoustic emission sensor 4 S4 in each group of acoustic emission sensors are arranged in a Z-shaped sensor array, and the coordinates of the acoustic emission sensor 1 S1, the acoustic emission sensor 2 S2, the acoustic emission sensor 3 S3, and the acoustic emission sensor 4 S4 are (x1, y1), (x2, y2), (x3, y3), and (x4, y4), respectively, and the distance between the acoustic emission sensor 1 S1 and the acoustic emission sensor 2 S2, the distance between the acoustic emission sensor 2 S2 and the acoustic emission sensor 3 S3, and the distance between the acoustic emission sensor 3 S3 and the acoustic emission sensor 4 S4 are all d; Step 32, consider the acoustic emission sensor 1 S1, the acoustic emission sensor 2 S2, and the acoustic emission sensor 3 S3 as a sensor system, and the relationship between the damage source P and the acoustic emission sensor 2 S2 is: The time difference between the damage source P reaching S1 and S2 is Δt 21 =t1-t2, the time difference from the damage source P to S2 and S3 is Δt 23 =t3-t2, then: get: Then we get: Wherein, α is the angle between the damage source P and the horizontal direction of the acoustic emission sensor S2; Step 33, consider the acoustic emission sensor 2 S2, the acoustic emission sensor 3 S3, and the acoustic emission sensor 4 S4 as a sensor system, and similarly obtain: Among them, β is the horizontal angle between the damage source P and the acoustic emission sensor S3, and the time difference between the damage source P reaching S2 and S3 is Δt 32 =t3-t2, the time difference between the damage source P reaching the sensors S4 and S3 is Δt 34 =t4-t3; Step 34: According to the formulas obtained in steps 32 and 33, a water channel crack location positioning model of the Z-shaped sensor array is obtained, and then the position of the damage source P (x P ,y P ), that is, to detect the crack position of the cooling water channel of the coal mining machine.

4. The method for detecting cracks in cooling water channels of a coal mining machine according to claim 3, characterized in that: Amplify, process and analyze the acoustic emission signals detected by the acoustic emission sensor.

5. The method for detecting cracks in cooling water channels of a coal mining machine according to claim 4, characterized in that: The acoustic emission signal detected by the acoustic emission sensor is converted into an electrical signal.

6. A detection system based on the method for detecting cracks in cooling water channels of a coal mining machine according to any one of claims 1 to 5, characterized in that: It includes an acoustic emission sensor unit, a signal acquisition unit, and an industrial computer. The acoustic emission sensor unit includes more than two acoustic emission sensor groups. The acoustic emission sensor group includes four acoustic emission sensors. The four acoustic emission sensors are arranged on the surface of the cooling water channel of the coal mining machine to form a Z-shaped sensor array. The acoustic emission sensor is used to capture the acoustic emission signal generated by the cracking of the water channel; the signal acquisition unit is used to collect the acoustic emission signal captured by the acoustic emission sensor and transmit it to the industrial computer; the industrial computer obtains the cracking position of the water channel according to the acoustic emission signal transmitted by the signal acquisition unit and the acoustic emission sensor position of the corresponding acoustic emission sensor group.

7. The inspection system according to claim 6, characterized in that: The acoustic emission sensor is arranged on the surface of the water channel in the electrical control box of the coal mining machine through a coupling agent.

8. The inspection system according to claim 7, characterized in that: The industrial computer sends the obtained water channel crack position to the coal mining machine control system, and the coal mining machine control system displays the water channel crack position and issues an early warning prompt.

9. The inspection system according to claim 8, characterized in that: The bottom plates of the acoustic emission sensor unit and the signal acquisition unit are copper plates.

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