Online monitoring device and method for concentration of respirable dust for coal mine

Abstract

The invention relates to a respiratory dust concentration online monitoring device and method for a coal mine, and belongs to the technical field of respiratory dust concentration monitoring. The device comprises a virtual impact separation module, a light scattering detection module, a flow control module and a data processing module. The virtual impact separation module is used for separating respirable dust and non-respirable dust; the respirable dust enters the light scattering detection module, the respirable dust is irradiated by a laser beam which is incident in the direction perpendicular to the flowing direction of the respirable dust, a scattered light signal obtained after dust scattering is transmitted to the data processing module, and the concentration of the respirable dust is calculated in real time; the flow control module is used for controlling the rotating speed of the sucking pump in real time. Through multi-technology fusion and intelligent algorithm compensation, the accuracy and environmental adaptability of respiratory dust concentration measurement are improved, the problems that a traditional separation device is prone to blockage and needs frequent maintenance are solved, and long-term continuous separation monitoring of respiratory dust can be achieved.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of respirable dust concentration monitoring, and relates to a coal mine respirable dust concentration online monitoring device and method. BACKGROUND

[0002] Respirable dust refers to dust particles with an aerodynamic diameter of less than 7.07 microns and a sampling efficiency of 50% when the aerodynamic diameter is 5 microns, which can be deposited in the alveoli according to the respirable dust standard determination method, and is the main factor leading to pneumoconiosis. Statistical data shows that pneumoconiosis accounts for about 90% of the total number of occupational disease cases in China. In 2020, a total of 14367 cases of occupational pneumoconiosis were reported nationwide, accounting for 84.2% of the total number of occupational disease cases, and has become a serious public health problem.

[0003] Currently, the respirable dust monitoring technology in coal mines has the following technical bottlenecks: Separation device clogging problem: traditional cyclone separation, horizontal ceramic separation and flat plate impact separation methods all have dust collection structures, and particulate matter is easy to accumulate in the separation device, leading to overload, clogging and secondary dust raising, which requires regular manual cleaning and is difficult to achieve long-term continuous monitoring. In high-concentration dust environment, the traditional cyclone separator may fail after continuous operation for one day.

[0004] Humidity interference problem: the humidity in the coal mine environment is high, when wet dust particles encounter a cooling surface, water may condense, causing the particles to solidify and adhere to the inside of the instrument, affecting the accuracy of the measurement results.

[0005] Measurement accuracy and stability problem: existing optical and electrostatic induction sensors are greatly affected by environmental factors such as temperature fluctuations and humidity changes, and the output signal is unstable, limiting the measurement accuracy.

[0006] Virtual impact technology, as a new type of particulate matter separation method, uses a collection chamber instead of a traditional impact plate, avoiding direct collision of particulate matter with solid surfaces, effectively solving problems such as particle rebound, overload and secondary dust raising. In recent years, this technology has been applied in the fields of atmospheric monitoring and biological aerosol sampling, but its application in coal mine respirable dust monitoring is still in the initial exploration stage. SUMMARY

[0007] Therefore, the present application aims to provide a coal mine respirable dust concentration online monitoring device and method based on virtual impact principle, solving the problems of existing respirable dust monitoring technology such as easy clogging of separation device, large environmental influence on measurement results, and inability to long-term continuous monitoring, achieving accurate separation of respirable dust, stable detection and long-term continuous operation, and providing reliable technical support for coal mine dust occupational hazard assessment and pneumoconiosis prevention.

[0008] To achieve the above objectives, the first aspect of the present invention provides an online monitoring device for respirable dust concentration in coal mines, which includes a virtual impact separation module, a light scattering detection module, a flow control module, and a data processing module.

[0009] The virtual impact separation module has a first outlet connected to a first suction pump, which discharges non-respirable dust from the dust-laden airflow. The second outlet of the virtual impact separation module is connected to a second suction pump and a light scattering detection module, which discharges respirable dust from the dust-laden airflow and into the light scattering detection module. The light scattering detection module uses a laser beam incident perpendicular to the flow direction of the respirable dust to irradiate the respirable dust and transmits the scattered light signal to the data processing module to calculate the respirable dust concentration in real time. The flow control module controls the rotation speed of the first and second suction pumps in real time.

[0010] Furthermore, the virtual impact separation module includes an inlet rectifier section, an acceleration nozzle, and a separation chamber connected in sequence. A first outlet is provided in the separation chamber as a non-respirable dust outlet, and a second outlet is provided as a respirable dust outlet.

[0011] Furthermore, the light scattering detection module includes a laser source, an optical lens group, a concave condenser lens, a photoelectric sensor, a detection circuit, and a light trap. The laser source is used to generate a laser beam perpendicular to the flow direction of the respirable dust, and the laser beam is collimated by the optical lens group to irradiate the respirable dust. The light trap is used to absorb the light beam that has passed through the respirable dust and propagated in the original direction. The concave condenser lens is used to reflect the light beam scattered by the respirable dust to the photoelectric sensor. The photoelectric sensor is used to convert the scattered light signal into an electrical signal and transmit it to the detection circuit.

[0012] Furthermore, the flow control module includes a gas flow meter and a PID controller; the gas flow meter monitors the sampled flow rate in real time and feeds the data back to the PID controller; the PID controller adjusts the speed of the pump to form a closed-loop control based on the deviation between the set flow rate and the actual flow rate, ensuring stable flow.

[0013] Furthermore, the device also includes a drying module for dehumidifying the extracted dust-laden airflow before sending it into the virtual impact separation module.

[0014] Furthermore, the device also includes a first filter disposed between the virtual impact separation module and the first suction pump for filtering non-respirable dust; and a second filter disposed between the light scattering detection module and the second suction pump for filtering respirable dust.

[0015] In a second aspect, the present invention provides a method for online monitoring of respirable dust concentration applied to the device described in the first aspect, the method comprising: The air pump is started to extract the dust-laden airflow, which is then dehumidified by the drying module before entering the virtual impact separation module. The virtual impact separation module separates respirable dust and non-respirable dust from the dust-laden airflow. The separated respirable dust airflow is then introduced into the light scattering detection module by the second air pump. A laser beam perpendicular to the direction of the respirable dust airflow is used to irradiate the respirable dust. The scattered light signal after being scattered by the respirable dust is received and converted into an electrical signal by a photoelectric sensor before being transmitted to the data processing module. During the sampling process, the flow control module uses an incremental PID control algorithm to control the speed of the air pump in real time to ensure stable sampling flow. The data processing module calculates the respirable dust concentration in real time using a dust concentration calculation model based on the light scattering signal intensity, current temperature, sampling flow rate, and sampling time. The calculation results are uploaded to the monitoring center, and corresponding alarm signals are triggered according to the respirable dust concentration level.

[0016] Furthermore, the incremental PID control algorithm used in the flow control module is expressed as follows:

[0017] In the formula, To control the increase in quantity, For the current moment The deviation between the setpoint and the actual flow rate , , These are PID parameters.

[0018] Furthermore, the dust concentration calculation model is expressed as follows:

[0019]

[0020] In the formula, This refers to the concentration of respirable dust. For device constants, This is the temperature compensation coefficient. The intensity of the scattered light. Background light intensity, This refers to the air extraction flow rate. Sampling time; , , These are the fitting coefficients. The temperature is at the current moment.

[0021] The beneficial effects of this invention are as follows: By organically integrating virtual impact separation technology, light scattering detection technology, and intelligent flow control technology, this invention achieves online, real-time, and accurate monitoring of respirable dust concentration in coal mines. The online monitoring device has the ability to operate continuously for a long time, the measurement results are reliable, and the maintenance requirements are low, providing an effective technical means for monitoring coal mine dust hazards and preventing pneumoconiosis.

[0022] This invention employs virtual impact separation technology to separate respirable and non-respirable dust, enabling long-term continuous monitoring of respirable dust without clogging issues, thus overcoming the inconvenience of frequent maintenance required by traditional separation devices. The invention utilizes a drying device to dehumidify the dust-laden airflow, reducing the impact of humidity on light scattering signals. Temperature compensation and adaptive filtering technologies are also introduced to enhance adaptability to complex environments and improve measurement accuracy and reliability. Furthermore, this invention employs an incremental closed-loop PID control algorithm, dynamically adjusting PID parameters based on the magnitude and trend of flow deviation, achieving rapid flow stabilization, improving anti-interference capabilities, and ensuring consistency between separation efficiency and detection accuracy.

[0023] In summary, this invention significantly improves the accuracy and environmental adaptability of respirable dust concentration measurement through the integration of multiple technologies and intelligent algorithm compensation. It is not only suitable for monitoring respirable dust in coal mines, but can also be extended to other industrial sites with dust hazards, such as tunnel construction, metal mines, and cement plants, and has broad application prospects and market potential.

[0024] 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

[0025] 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: Figure 1 This is a schematic diagram of the structure of an online monitoring device for respirable dust concentration in coal mines provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the virtual impact separation module structure; Figure 3 This is a schematic diagram of the light scattering detection module. Figure 4 This is a schematic diagram of the flow control module structure; Figure 5 This is a schematic flowchart of an online monitoring method for respirable dust concentration provided in an embodiment of the present invention; Figure 6 This is a schematic diagram of the internal structure of the separation chamber.

[0026] Reference numerals: 1-Inlet rectifier section; 2-Accelerating nozzle; 3-Separation chamber; 4-Respirable dust outlet; 5-Non-respirable dust outlet; 6-Respirable dust chamber; 7-Non-respirable dust chamber. Detailed Implementation

[0027] 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.

[0028] The accompanying drawings are for illustrative purposes only and are schematic diagrams, not actual pictures, and 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.

[0029] 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.

[0030] To address the problems of existing respirable dust monitoring technologies, such as easy clogging of separation devices, significant environmental influence on measurement results, and inability to conduct long-term continuous monitoring, an embodiment of the present invention provides an online monitoring device for respirable dust concentration in coal mines based on the principle of virtual impact.

[0031] like Figure 1As shown, the online monitoring device provided in this embodiment includes four core components: a virtual impact separation module, a light scattering detection module, a flow control module, and a data processing module. The dust-laden airflow, under the combined action of a first and second extraction pump, first passes through a drying module to remove moisture from the dust, then passes through the virtual impact separation module to separate respirable dust. The non-respirable dust portion, under the action of the first extraction pump, is filtered by a first filter before being discharged from the online monitoring device. The respirable dust portion, under the action of the second extraction pump, first passes through the light scattering detection module for signal detection, and the respirable dust airflow is then filtered by a second filter before being discharged from the online monitoring device. To ensure stable flow rates for the first and second extraction pumps, their control signals are automatically adjusted by the flow control module; the signal from the light scattering detection module is input into the data processing module to calculate the respirable dust concentration value.

[0032] The following sections provide a detailed explanation of each of the four modules: (1) Virtual impact separation module like Figure 2 As shown, the virtual impact separation module includes an inlet rectifier section 1, an acceleration nozzle 2, a separation chamber 3, a respirable dust outlet 4, and a non-respirable dust outlet 5.

[0033] When the dust-laden airflow enters the virtual impact separation module at a certain speed, it is accelerated sequentially through the inlet rectifier section 1 and the accelerating nozzle 2 to form a high-speed jet. The internal structure of the separation chamber 3 (such as...) Figure 6 Under the influence of (as shown), the airflow is divided into two streams: most of the gas carries fine particles with less inertia into the respirable dust outlet 4; a small portion carries coarse particles with greater inertia into the non-respirable dust outlet 5.

[0034] (2) Light scattering detection module The light scattering detection module is used to measure the concentration of the separated respirable dust, and its structure is as follows: Figure 3 As shown, a right-angle scattered light detection scheme is adopted. This module consists of a laser source (wavelength 650nm), an optical lens group, a concave condenser lens, a light trap, a photoelectric sensor, and a detection circuit.

[0035] The laser beam output from the laser source is perpendicular to the airflow direction; after the laser beam is scattered by dust, the scattered light is received by the photoelectric sensor and converted into an electrical signal; the detection circuit uses a low-noise amplifier to amplify the weak photoelectric signal and designs an adaptive filter circuit to eliminate interference.

[0036] (3) Flow control module The flow control module is used to maintain a stable pumping flow rate, which is crucial for ensuring separation efficiency and detection accuracy. Its structure is as follows: Figure 4 As shown, it consists of a gas flow meter and an incremental PID controller.

[0037] An orifice plate gas flow meter is used to monitor the sampled flow rate in real time, and the data is fed back to a PID controller. The PID controller adjusts the speed of the pump based on the deviation between the set value and the actual value to form a closed-loop control, ensuring stable flow.

[0038] The flow control algorithm uses an incremental PID formula:

[0039] in, To control the increase in quantity, For the current moment Error at time, , , These are PID parameters.

[0040] (4) Data processing module The data processing module is responsible for processing detection signals, temperature detection, calculating dust concentration, and realizing data communication and alarm functions.

[0041] The process of dust concentration calculation by the data processing module is as follows: The dust concentration calculation model based on the principle of light scattering is expressed as follows:

[0042] in, Dust concentration, This is the device constant (which can be obtained by placing the online monitoring device in a dust environment with a known concentration and then calculating it using the above formula). This is the temperature compensation coefficient. The intensity of the scattered light. Background light intensity, This refers to the air extraction flow rate. Sampling time.

[0043] By experimentally measuring the "light intensity-concentration" relationship at different temperatures, a calculation model for the temperature compensation coefficient was established.

[0044] in, , , These are the fitting coefficients. The current temperature. Fitting coefficients. , , Based on experimental data, and using the least squares method for fitting.

[0045] Based on the calculated respirable dust concentration, the data processing module determines whether to activate the intelligent alarm and data communication. If the respirable dust concentration exceeds the limit and an alarm is required, a multi-level alarm mechanism is employed, triggering different audible and visual alarm signals according to different dust concentration levels. Data communication utilizes RS485 and Ethernet to upload monitoring data to the monitoring center in real time.

[0046] Another embodiment of the present invention provides a method for online monitoring of respirable dust concentration in coal mines, such as... Figure 5 As shown, the method includes: 1. First, the dust-laden airflow is drawn into the online monitoring device. The dust-laden airflow is dehumidified by the drying module to remove moisture from the airflow and reduce the interference of humidity on subsequent measurements.

[0047] 2. Under the action of the air pump, the dust-laden airflow dehumidified by the drying module enters the virtual impact separation module. It forms a high-speed jet through the acceleration nozzle 2 and divides the airflow into two streams according to the difference in particle inertia. The fine particles with smaller inertia enter the respirable dust outlet with most of the gas, while the coarser particles with larger inertia enter the non-respirable dust outlet under the action of the first air pump, thus achieving non-contact and non-clogging respirable dust separation.

[0048] 3. The separated respirable dust airflow is introduced into the light scattering detection module through the second air pump. The dust particles are irradiated with a vertically incident laser beam, and the scattered light signal after dust scattering is received. The signal is converted into an electrical signal by a photoelectric sensor, and an adaptive filtering circuit is used to process the signal to eliminate environmental interference.

[0049] 4. During the sampling process, the speed of the air pump is controlled in real time through the flow control module. Specifically, the gas flow meter monitors the sampling flow in real time and uses an incremental PID control algorithm to dynamically adjust the speed of the air pump, forming a closed-loop flow control to ensure stable sampling flow, thereby improving the consistency between separation and detection.

[0050] The incremental PID control algorithm is shown in the following equation:

[0051] To control the increase in quantity, For the current moment The deviation between the setpoint and the actual flow rate , , These are PID parameters.

[0052] 5. Based on the light scattering signal intensity, current temperature, sampling flow rate, and sampling time, a temperature-compensated dust concentration calculation model is used to calculate the respirable dust concentration in real time. The calculation results are uploaded to the monitoring center through the communication interface, and corresponding alarm signals are triggered according to the concentration level.

[0053] The dust concentration calculation model is expressed as follows:

[0054]

[0055] in, This refers to the concentration of respirable dust. For device constants, This is the temperature compensation coefficient. The intensity of the scattered light. Background light intensity, This refers to the air extraction flow rate. Sampling time. , , These are the fitting coefficients. The current temperature is given by the fitting coefficient. , , Based on experimental data, and using the least squares method for fitting.

[0056] In summary, this invention achieves online, real-time, and accurate monitoring of respirable dust concentration in coal mines by integrating virtual impact separation technology, light scattering detection technology, and intelligent flow control technology. The monitoring device has the capability for long-term continuous operation, provides reliable measurement results, and requires minimal maintenance, offering an effective technical means for monitoring coal mine dust hazards and preventing pneumoconiosis. This invention is not only applicable to respirable dust monitoring in underground coal mines but can also be extended to other industrial sites with dust hazards, such as tunnel construction, metal mines, and cement plants, demonstrating broad application prospects and market potential.

[0057] 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. An online monitoring device for respirable dust concentration in coal mines, characterized in that, The system includes a virtual impact separation module, a light scattering detection module, a flow control module, and a data processing module. The first outlet of the virtual impact separation module is connected to a first suction pump, which discharges non-respirable dust from the dust-laden airflow. The second outlet of the virtual impact separation module is connected to a second suction pump and the light scattering detection module, which discharges respirable dust from the dust-laden airflow and into the light scattering detection module. The light scattering detection module uses a laser beam incident perpendicular to the flow direction of the respirable dust to irradiate the respirable dust and transmits the scattered light signal after scattering to the data processing module to calculate the respirable dust concentration in real time. The flow control module controls the rotation speed of the first and second suction pumps in real time.

2. The apparatus according to claim 1, characterized in that, The virtual impact separation module includes an inlet rectifier section, an acceleration nozzle, and a separation chamber connected in sequence. The separation chamber is provided with a first outlet and a second outlet, which are used to discharge non-respirable dust and respirable dust, respectively.

3. The apparatus according to claim 1, characterized in that, The light scattering detection module includes a laser source, an optical lens group, a concave condenser lens, a photoelectric sensor, a detection circuit, and a light trap. The laser source is used to generate a laser beam perpendicular to the flow direction of the respirable dust. The laser beam is collimated by the optical lens group and then irradiates the respirable dust. The light trap is used to absorb the light beam that has passed through the respirable dust and is propagating in the original direction. A concave condenser is used to reflect the light beam scattered by respirable dust to a photoelectric sensor; the photoelectric sensor is used to convert the scattered light signal into an electrical signal and transmit it to the detection circuit.

4. The apparatus according to claim 1, characterized in that, The flow control module includes a gas flow meter and a PID controller; the gas flow meter monitors the sampled flow rate in real time and feeds the data back to the PID controller; the PID controller adjusts the speed of the pump according to the deviation between the flow setpoint and the actual value to form a closed-loop control, ensuring stable flow.

5. The apparatus according to claim 1, characterized in that, The device also includes a drying module for dehumidifying the extracted dust-laden airflow before sending it into the virtual impact separation module.

6. The apparatus according to claim 1, characterized in that, The device also includes a first filter disposed between the virtual impact separation module and the first suction pump for filtering non-respirable dust; and a second filter disposed between the light scattering detection module and the second suction pump for filtering respirable dust.

7. A method for online monitoring of respirable dust concentration applied to the apparatus described in any one of claims 1 to 6, characterized in that, The method includes: The air pump is started to extract the dust-laden airflow, which is then dehumidified by the drying module before entering the virtual impact separation module. The virtual impact separation module separates respirable dust and non-respirable dust from the dust-laden airflow. The separated respirable dust airflow is then introduced into the light scattering detection module by the second air pump. A laser beam perpendicular to the direction of the respirable dust airflow is used to irradiate the respirable dust. The scattered light signal after being scattered by the respirable dust is received and converted into an electrical signal by a photoelectric sensor before being transmitted to the data processing module. During the sampling process, the flow control module uses an incremental PID control algorithm to control the speed of the air pump in real time to ensure stable sampling flow. The data processing module calculates the respirable dust concentration in real time using a dust concentration calculation model based on the light scattering signal intensity, current temperature, sampling flow rate, and sampling time. The calculation results are uploaded to the monitoring center, and corresponding alarm signals are triggered according to the respirable dust concentration level.

8. The method according to claim 7, characterized in that, The incremental PID control algorithm used in the flow control module is expressed as follows: In the formula, To control the increase in quantity, For the current moment The deviation between the setpoint and the actual flow rate , , These are PID parameters.

9. The method according to claim 7, characterized in that, The dust concentration calculation model is expressed as follows: In the formula, This refers to the concentration of respirable dust. For device constants, This is the temperature compensation coefficient. The intensity of the scattered light. Background light intensity, This refers to the air extraction flow rate. Sampling time; , , These are the fitting coefficients. The temperature is at the current moment.

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