A full-range automatic calibration coal mine laser dust concentration detection device and method

Abstract

This invention relates to a full-range automatic calibration device and method for detecting coal mine laser dust concentration, belonging to the field of coal mine dust concentration detection technology. The device includes a power supply and digital signal processing section and a dust concentration detection probe. The dust concentration detection probe includes a dust guide plate, a dust concentration testing section, and a control and signal processing circuit board. The dust concentration testing section includes a laser, a dust concentration detection area, a filter, a light trap, a scattered light intensity detector, two automatically calibrated scattering plates, and a scattering plate hiding slot. When the detection device is working normally, the scattering plates are hidden in the hiding slot to prevent dust contamination. When the detection device needs calibration, the digital signal is transmitted to the circuit board to control a motor to push the scattering plates out of the hiding slot, positioning them perpendicular to the laser beam to ensure the laser beam passes perpendicularly through the center of the scattering plates. This invention has a simple structure and can achieve full-range automatic calibration of the detection device.

Description

Technical Field

[0001] This invention belongs to the field of coal mine dust concentration detection technology, and relates to a full-range automatic calibration coal mine laser dust concentration detection device and method. Background Technology

[0002] Coal mine dust hazards remain a weak link in coal mine safety production. Dust generated during coal mine production can easily cause dust explosions and pneumoconiosis. Therefore, accelerating coal mine dust control, achieving accurate detection of coal mine dust, and creating a clean and safe coal mine environment are urgently needed.

[0003] Light scattering dust concentration detection technology is widely used due to its high accuracy and sensitivity, and it was the earliest technology applied to dust concentration sensors in coal mines. However, the complex environment of coal mines, with its high dust concentration and moisture content, easily contaminates the light-scattering intensity sensing device with dust, reducing the detection accuracy or even causing it to fail. This necessitates frequent and complex maintenance by workers, which can easily damage the detection unit, hindering the effective application of light scattering dust concentration detection technology in coal mines. Therefore, there is an urgent need for a dust concentration detection device capable of automatic calibration to achieve accurate dust concentration detection. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a full-range automatic calibration device and method for coal mine laser dust concentration detection, which solves the problem of low sensitivity and large dust concentration detection error caused by photodiode contamination in current dust concentration detection devices. At the same time, it also solves the problem of single-point calibration of dust concentration testing devices in current detection methods, and the complexity and large size of the equipment.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A full-range automatic calibration coal mine laser dust concentration detection device includes a power supply and digital signal processing section and a dust concentration detection probe; the power supply and digital signal processing section includes a circuit board 8, a display window 3, and an audible and visual alarm 2; the dust concentration detection probe includes a dust guide plate 5, a dust concentration testing section 10, and a control and signal processing circuit board 25; the dust concentration testing section 10 includes a laser 17, a dust concentration detection area 18, a filter 19, a light trap 20, and a scattered light intensity detector 24;

[0007] Under the influence of airflow, external dust enters the dust concentration detection area 18 inside the detection device through the guide hole 13 of the dust guide plate 5. Then, under the influence of airflow, the dust flows out through the guide hole at the other end of the dust guide plate 5. The laser 17 emits a laser beam that passes through the dust concentration detection area 18 and then reaches the light trap 20. The dust in the dust concentration detection area 18 scatters the laser beam. The scattered light passes through the filter 19 and reaches the scattered light intensity detector 24. The scattered light intensity detector 24 transmits the detection value to the control and signal processing circuit board 25. Then, the digital signal is transmitted to the circuit board 8 through the shielded wire 9. The secondary calculation is performed to obtain the dust concentration value of the detection area. The detection value is displayed in the display window 3, and the test result is uploaded to the monitoring system through the power and signal wiring terminal 4. If the detected dust concentration value is greater than the set threshold, the audible and visual alarm 2 will issue a warning signal.

[0008] Preferably, the dust concentration testing section 10 further includes two automatically calibrated scattering plates, namely scattering plate I 15 and scattering plate II 21, and a scattering plate hiding slot; when the dust concentration detection device is working normally, the scattering plates are hidden in the hiding slot to avoid dust contamination; when the dust concentration detection device needs to be calibrated, the digital signal is transmitted to the circuit board 8 to control the motor to push the scattering plate out of the scattering plate hiding slot, making the scattering plate perpendicular to the laser beam, ensuring that the laser beam passes perpendicularly through the center of the scattering plate.

[0009] Furthermore, the high purity of the scattering sheet I15 results in scattered light equivalent to 200 mg / m³. 3 The scattered light produced by the coal powder, due to the low purity of the scattering sheet II21, resulted in scattered light equivalent to 600 mg / m³. 3 The scattered light produced by pulverized coal, when superimposed by scatterer I15 and scatterer II21, is equivalent to 800 mg / m³. 3 Scattered light produced by coal powder;

[0010] The calibration status includes four states:

[0011] State 1: Both diffuser I15 and diffuser II21 are in the hidden slot, which is the zero point, and the dust concentration test value is a1;

[0012] State 2: Scattering plate I15 is in the hidden slot, scattering plate II21 is in dust concentration detection area 18, simulating a dust concentration of 200 mg / m³. 3 Calibration plate, dust concentration test value a2;

[0013] State 3: Scattering plate I15 is in dust concentration detection area 18, scattering plate II21 is in the hidden slot, simulating a dust concentration of 600 mg / m³. 3 Calibration plate, dust concentration test value a3;

[0014] State 4: Both diffuser I15 and diffuser II21 are in dust concentration detection area 18, simulating a dust concentration of 800 mg / m³. 3 Calibration plate, dust concentration test value a4.

[0015] Furthermore, the automatic calibration process is as follows: First, a judgment is made. If the test error in any of the four states exceeds 15%, that is, if formula S1 is satisfied, the circuit board 8 will issue a command to perform full-range automatic calibration. When the dust concentration detection device receives the calibration command from the circuit board 8, it turns off the laser, hides the diffuser I 15 and diffuser II 21, and the test data is (a1, 0) (test value before calibration, calibration target value). Then, it turns on the laser 17, pushes out diffuser I, hides diffuser II, and the test data is (a2, 200) (test value before calibration, calibration target value). Then, it turns on the laser, pushes out diffuser II, hides diffuser I, and the test data is (a3, 600) (test value before calibration, calibration target value). Then, it turns on the laser, pushes out diffuser II, pushes out diffuser I, and the test data is (a4, 800) (test value before calibration, calibration target value). Then, full-range automatic calibration is performed through formula S2. After calibration is completed, the laser is turned on and the detection state is returned.

[0016] Formula for entering calibration state:

[0017] (S1)

[0018] Once any one of the four states is met, the sensor enters the full-range automatic calibration process.

[0019] Full-range automatic calibration formula:

[0020] (S2)

[0021] in, y To calibrate the target value, x These are the test values ​​before calibration.

[0022] The beneficial effects of this invention are as follows: This invention solves the problem of reduced detection accuracy of coal mine dust concentration sensors after being contaminated by dust. It adopts a simple structure that can realize automatic calibration of the dust concentration detection device across the entire range, rather than single-point calibration, ensuring the detection accuracy of each point across the entire range of the dust concentration detection equipment, guaranteeing the validity of the detection data of the underground dust concentration sensor in the coal mine, and the device and method have high adaptability to harsh dust environments.

[0023] Other advantages, objectives, and features of the invention will be set forth in part in the description which follows, and in part will be apparent to those skilled in the art from the following examination, or may be learned from practice of the invention. The objectives and other advantages of the invention can be realized and obtained through the following description. Attached Figure Description

[0024] To make the objectives, technical solutions, and advantages of the present invention clearer, the preferred embodiments of the present invention will be described in detail below with reference to the accompanying drawings, wherein:

[0025] Figure 1 This is a schematic diagram of the structure of the full-range automatic calibration coal mine laser dust concentration detection device of the present invention;

[0026] Figure 2 This is a schematic diagram of the dust concentration testing section.

[0027] Figure 3 This is a schematic diagram of the internal structure of a dust concentration detection probe.

[0028] Figure 4 This is a schematic diagram of the calibration status;

[0029] Figure 5 This is a schematic diagram of calibration state two;

[0030] Figure 6 This is a schematic diagram of calibration state three;

[0031] Figure 7 This is a schematic diagram of calibration state four;

[0032] Figure 8 This is a flowchart of the full-range automatic calibration process.

[0033] Reference numerals: 1-Hanging bracket, 2-Audible and visual alarm, 3-Display window, 4-Power and signal wiring terminals, 5-Dust guide plate, 6-Front shell, 7-Rear shell, 8-Circuit board, 9-Shielding wire (connecting the probe), 10-Dust concentration testing section, 11-Fixing bolt, 12-Probe metal shell, 13-Guiding hole, 14-Diffuser I hidden slot, 15-Diffuser I, 16-Motor I, 17-Laser, 18-Dust concentration detection area, 19-Filter, 20-Light trap, 21-Diffuser II, 22-Motor II, 23-Diffuser II hidden slot, 24-Scattered light intensity detector, 25-Control and signal processing circuit board. Detailed Implementation

[0034] The following specific examples illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0035] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures. They should not be construed as limiting the invention. To better illustrate the embodiments of the invention, some parts in the drawings may be omitted, enlarged, or reduced, and do not represent the actual product dimensions. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings.

[0036] In the accompanying drawings of the embodiments of the present invention, the same or similar reference numerals correspond to the same or similar components. In the description of the present invention, it should be understood that if terms such as "upper," "lower," "left," "right," "front," and "rear" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings, they are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, the terms used to describe positional relationships in the drawings are only for illustrative purposes and should not be construed as limiting the present invention. For those skilled in the art, the specific meaning of the above terms can be understood according to the specific circumstances.

[0037] Please see Figures 1 to 8 This invention provides a full-range automatic calibration device for coal mine laser dust concentration detection, comprising a power supply and digital signal processing section and a dust concentration detection probe, as shown below. Figure 1 and Figure 2 As shown.

[0038] The power supply and digital signal processing section mainly includes the device's mounting bracket 1, audible and visual alarm 2, display window 3, power and signal terminals 4, circuit board 8, front shell 6, rear shell 7, and shielded cable 9 (for connecting the probe). The dust concentration detection probe includes a dust concentration testing section 10, a dust guide plate 5 (with 40mm*5mm guide holes 13), fixing bolts 11, and a metal probe housing 12.

[0039] The working process of the dust concentration detection device is as follows: Dust, under the influence of airflow, enters the internal testing area of ​​the detection device through the guide holes 13 of the dust guide plate 5. Then, under the same airflow, the dust flows out through the guide holes at the other end of the dust guide plate 5. Inside the dust concentration detection probe's testing area, the dust scatters the laser light. The scattered light passes through the filter 19 and reaches the scattered light intensity detector 24. The scattered light intensity detector 24 transmits the detected value to the control and signal processing circuit board 25. Then, through the shielded wire 9, the digital signal is transmitted to the circuit board 8 for secondary calculation to obtain the dust concentration value of the testing area. The detected value is displayed in the display window 3, and the test result is uploaded to the monitoring system through the power and signal terminals 4. If the detected dust concentration value exceeds the set threshold, the audible and visual alarm 2 issues a warning signal.

[0040] Self-calibration function of dust concentration detection device: The calibration function is mainly reflected in the internal devices of the dust concentration detection section, such as... Figure 3 As shown, laser 17 emits a laser beam that passes through dust concentration detection area 18 and then reaches light trap 20. The scattered light passes through a filter and reaches scattered light intensity detector 24 to detect dust concentration. This device adds two automatically calibrated scattering plates, namely scattering plate I 15 and scattering plate II 21. This invention emphasizes the adaptability of the dust concentration detection device to harsh conditions. For accurate calibration, it is necessary to ensure that the scattering plates are not contaminated by dust and to keep them clean for a long time. Therefore, the device is equipped with a scattering plate hiding slot. When the sensor is working normally, the scattering plate is hidden in the hiding slot to avoid dust contamination. When the dust concentration detection device needs calibration, the controller controls motors I and II to push the scattering plate out of the scattering plate hiding slot, making the scattering plate perpendicular to the laser beam, ensuring that the laser beam passes perpendicularly through the center of the scattering plate.

[0041] System control flowchart, such as Figure 8 As shown: The dust concentration detection device operates in harsh conditions in coal mines for extended periods. Dust contaminates the filter in the dust concentration detector probe, reducing the intensity of scattered light passing through the filter and causing the output value of the scattered light intensity detector to be lower. Therefore, it is necessary to design an automatic calibration device for the sensor to correct the sensor's detection value at any time, ensuring that the dust concentration detection device has high detection accuracy.

[0042] The designed scatterer I15 and scatterer II21 are different. Scatterer I15 has high purity, and the scattered light produced by the designed scatterer is equivalent to 200 mg / m². 3 The scattered light produced by coal powder, due to the low purity of the scattering sheet II21, resulted in scattered light equivalent to 600 mg / m³. 3The scattered light generated by coal dust, superimposed by scatterer I15 and scatterer II21, is equivalent to the scattered light generated by 800 mg / m³ of coal dust. The calibration state diagram is shown in Figure 4-7. State 1 is zero point, with a test value of a1. State 2 simulates a dust concentration of 200 mg / m³. 3 The calibration plate test value a2, state three, simulates a dust concentration of 600 mg / m³. 3 Calibration test value a3, state four is a simulated dust concentration of 800mg / m³ 3 Calibration test value a4.

[0043] Full-range automatic calibration process as follows Figure 8 As shown. First, a judgment is made. If the test error in any of the four states exceeds 15% (judgment formula S1), the controller will issue a command to perform full-range automatic calibration. The dust concentration detection device receives the calibration command from the controller, turns off the laser, hides diffuser I and II, and the test data is (a1,0) (test value before calibration, calibration target value). Then, the laser is turned on, diffuser I is pushed out, diffuser II is hidden, and the test data is (a2,200) (test value before calibration, calibration target value). Then, the laser is turned on, diffuser II is pushed out, diffuser I is hidden, and the test data is (a3,600) (test value before calibration, calibration target value). Then, the laser is turned on, diffuser II is pushed out, diffuser I is pushed out, and the test data is (a4,800) (test value before calibration, calibration target value). Then, full-range automatic calibration is performed using formula S2. After calibration, the laser is turned on and the device returns to the detection state.

[0044] Formula for entering calibration state:

[0045] (S1)

[0046] Once any one of the four states is met, the sensor enters the full-range automatic calibration process.

[0047] Full-range automatic calibration formula:

[0048] (S2)

[0049] in, y To calibrate the target value, x These are the test values ​​before calibration.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A full-range automatic calibration device for detecting laser dust concentration in coal mines, characterized in that, The device includes a power supply and digital signal processing section and a dust concentration detection probe; the power supply and digital signal processing section includes a circuit board (8); the dust concentration detection probe includes a dust guide plate (5), a dust concentration testing section (10) and a control and signal processing circuit board (25); the dust concentration testing section (10) includes a laser (17), a dust concentration detection area (18), a filter (19), a light trap (20), a scattered light intensity detector (24), two automatically calibrated scattering plates, namely scattering plate I (15) and scattering plate II (21), and a scattering plate hiding slot; when the dust concentration detection device is working normally, the scattering plate is hidden in the hiding slot to avoid the scattering plate being contaminated by dust; when the dust concentration detection device needs to be calibrated, the digital signal is transmitted to the circuit board (8) to control the motor to push the scattering plate out of the scattering plate hiding slot, making the scattering plate perpendicular to the laser beam, so that the laser beam passes perpendicularly from the center of the scattering plate; Under the action of airflow, external dust enters the dust concentration detection area (18) inside the detection device through the guide hole (13) of the dust guide plate (5), and then the dust flows out through the guide hole at the other end of the dust guide plate (5) under the action of airflow; the laser (17) emits a laser beam that passes through the dust concentration detection area (18) and then reaches the light trap (20). The dust scatters the laser in the dust concentration detection area (18). The scattered light passes through the filter (19) and reaches the scattered light intensity detector (24). The scattered light intensity detector (24) transmits the detection value to the control and signal processing circuit board (25), and then transmits the digital signal to the circuit board (8) through the shielding line (9) for secondary calculation to obtain the dust concentration value of the detection area; Scattering plate I (15) has high purity, and the scattered light produced by the designed scattering plate is equivalent to 200 mg / m². 3 The scattered light produced by the coal powder, the purity of the scattering sheet II (21) is low, and the scattered light produced by the designed scattering sheet is equivalent to 600mg / m 3 The scattered light produced by the coal powder, when superimposed by scatterer I (15) and scatterer II (21), is equivalent to 800 mg / m³. 3 Scattered light produced by coal powder; The calibration status includes four states: State 1: Both diffuser I (15) and diffuser II (21) are in the hidden slot, which is the zero point, and the dust concentration test value is a1; State 2: Scattering plate I (15) is in the hidden slot, scattering plate II (21) is in the dust concentration detection area (18), simulating a dust concentration of 200 mg / m³. 3 Calibration plate, dust concentration test value a2; State 3: Scattering plate I (15) is in the dust concentration detection area (18), scattering plate II (21) is in the hidden slot, simulating a dust concentration of 600 mg / m³. 3 Calibration plate, dust concentration test value a3; State 4: Both diffuser I (15) and diffuser II (21) are in the dust concentration detection area (18), simulating a dust concentration of 800 mg / m³. 3 Calibration plate, dust concentration test value a4.

2. The full-range automatic calibration coal mine laser dust concentration detection device according to claim 1, characterized in that, The automatic calibration process is as follows: First, a judgment is made. If the test error of any one of the four states exceeds 15%, that is, if the formula S1 is satisfied, the circuit board (8) will issue an instruction to perform full-range automatic calibration. When the dust concentration detection device receives the calibration instruction from the circuit board (8), it turns off the laser, hides the diffuser I (15) and diffuser II (21), and the test data is (a1,0). Then, it turns on the laser (17), pushes out diffuser I, hides diffuser II, and the test data is (a2,200). Then, it turns on the laser, pushes out diffuser II, hides diffuser I, and the test data is (a3,600). Then, it turns on the laser, pushes out diffuser II, pushes out diffuser I, and the test data is (a4,800). Then, it performs full-range automatic calibration through formula S2. After the calibration is completed, it turns on the laser and returns to the detection state. Formula for entering calibration state: （S1） Once any one of the four states is met, the sensor enters the full-range automatic calibration process. Full-range automatic calibration formula: （S2） in, y To calibrate the target value, x These are the test values ​​before calibration.

3. The full-range automatic calibration coal mine laser dust concentration detection device according to claim 1 or 2, characterized in that, The power supply and digital signal processing section also includes a display window (3) and an audible and visual alarm (2). After the circuit board (8) performs secondary calculations to obtain the dust concentration value of the detection area, the detection value is displayed in the display window (3), and the test result is uploaded to the monitoring system through the power supply and signal terminal (4). If the detected dust concentration value is greater than the set threshold, the audible and visual alarm (2) will issue a warning signal.

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