F-type air duct air volume adjusting system capable of measuring air leakage

Abstract

This invention relates to the field of tunnel ventilation control technology, specifically to an F-type ventilation duct airflow adjustment system capable of measuring air leakage. The system includes: a ventilation duct unit, a data acquisition unit, an air leakage measurement unit, and a ventilation control unit; the ventilation duct unit includes a near-face ventilation duct, a far-face ventilation duct, and a main ventilation duct; the data acquisition unit includes a wind speed sensor and a methane sensor for data acquisition; the air leakage measurement unit calculates the air leakage of the near-face ventilation duct, the far-face ventilation duct, and the main ventilation duct to obtain the total air leakage; the ventilation control unit includes an air compressor control device, an electric damper, an electric damper controller, and a data sensor; wherein the electric damper controller is connected to the electric damper; and the airflow is adjusted based on the total air leakage. This invention can accurately calculate the air leakage of the ventilation duct, thereby improving the accuracy of airflow adjustment.

Description

Technical Field

[0001] This invention relates to the field of forced ventilation technology for long tunnels, and specifically to an F-type duct airflow regulation system that can measure air leakage. Background Technology

[0002] In high-altitude regions, the environment is typically frigid and oxygen-deficient, with low air pressure and extremely harsh conditions. Ventilation is a critical issue in tunnel construction and a global technical challenge. Long-distance ventilation is constrained by numerous factors, making it difficult to ensure optimal construction results. Major pollution sources during tunnel construction include blasting fumes and harmful gases emitted from diesel machinery. Furthermore, the low oxygen content in high-altitude areas, along with significant variations in temperature, humidity, and atmospheric pressure, leads to insufficient oxygen intake, reducing diesel engine efficiency and significantly increasing harmful gas emissions. This poses a threat to worker health and causes environmental pollution. During ventilation, significant airflow loss occurs over long distances, necessitating accurate calculations of long-distance air leakage.

[0003] In traditional long-distance tunnel ventilation, the air leakage of the ventilation duct is calculated according to the standard marked on the duct at the factory. However, in actual operation, due to different combinations of ventilation ducts and environmental influences, the standard air leakage is not applicable to actual applications. Furthermore, in traditional long-distance tunnel ventilation systems, the ventilation control for working faces at different distances is not precise enough, resulting in energy loss. Summary of the Invention

[0004] To address the aforementioned technical problems, the present invention aims to provide an F-type air duct airflow regulation system capable of measuring air leakage, the specific technical solution of which is as follows:

[0005] One embodiment of the present invention provides an F-type duct airflow regulation system with measurable air leakage, the system comprising: a duct ventilation unit, a data acquisition unit, an air leakage measurement unit, and a ventilation control unit;

[0006] The ventilation unit includes a near-field working face ventilation duct, a far-field working face ventilation duct, and a main ventilation duct; the near-field working face ventilation duct and the far-field working face ventilation duct are respectively connected to the main ventilation duct to form an F-shaped ventilation duct; the ventilation unit also includes an air compressor, which is connected to the main ventilation duct and used to deliver air volume;

[0007] The data acquisition unit includes a wind speed sensor and a methane sensor, which are used to collect data. The wind speed sensor is installed at the air outlet of the air duct at the near working face and the air duct at the far working face, respectively. The methane sensor is installed inside the near working face and the far working face, respectively.

[0008] The air leakage measurement unit is used to calculate the air leakage of the near-distance working face ventilation duct, the far-distance working face ventilation duct and the main ventilation duct, and obtain the total air leakage.

[0009] The ventilation control unit includes an air compressor control device, an electric damper, an electric damper controller, and a data sensor; wherein the electric damper controller is connected to the electric damper and adjusts the air volume based on the total air leakage.

[0010] Preferably, the wind speed sensor and methane sensor include wind speed sensor C1 and wind speed sensor C2 respectively; wind speed sensor C1 is installed at the air outlet of the air duct at the near working face; wind speed sensor C2 is installed at the air outlet of the air duct at the far working face; the methane sensor includes methane sensor T1 and methane sensor T2, methane sensor T1 is installed outside the air outlet end of the air duct at the near working face, at a distance from the working face within a preset range; methane sensor T2 is installed outside the air outlet end of the air duct at the far working face, at a distance from the working face within a preset range.

[0011] Preferably, the data acquisition unit further includes a first safety monitoring substation and a second safety monitoring substation; wind speed sensor C1 is connected to the first safety monitoring substation, and the first safety monitoring substation is connected to the second safety monitoring substation; wind speed sensor C2 is connected to the second safety monitoring substation; the second safety monitoring substation is connected to the electric damper controller and the air compressor control device respectively.

[0012] Preferably, the air compressor control device is mechanically connected to the air compressor, and the electric damper is electrically connected to the electric damper controller.

[0013] Preferably, the ventilation control unit further includes a first power-off device and a second power-off device; methane sensor T1 and methane sensor T2 are respectively connected to the first safety monitoring substation and the second safety monitoring substation; the first safety monitoring substation and the second safety monitoring substation are respectively connected to the low-voltage power supply switch through the first power-off device and the second power-off device, and the low-voltage power supply switch is connected to the air compressor.

[0014] Preferably, the calculation of air leakage from the ventilation duct at the distance from the working face, the ventilation duct at the far working face, and the main ventilation duct includes:

[0015] Obtain the straight section, bend section, and electrically controlled damper section of the near-field working face duct, the far-field working face duct, and the main ventilation duct; wherein the near-field working face duct includes one straight section, one bend section, and one electrically controlled damper section; the far-field working face duct includes one straight section and one bend section; and the main ventilation duct includes one straight section; calculate the air leakage of the ducts at distances from the working face duct, the far-field working face duct, and the main ventilation duct based on the obtained straight section, bend section, and electrically controlled damper section.

[0016] Preferably, based on the obtained data for the straight section, curved section, and electrically controlled damper section of the ventilation duct, the air leakage rate of the ventilation duct at the distance from the working face, the long-distance working face ventilation duct, and the main ventilation duct is calculated, including:

[0017] Divide the straight sections and bend sections corresponding to the ventilation ducts at the distance from the working face, the long-distance working face, and the main ventilation duct into n equal parts to obtain n differential ventilation duct sections and n leakage nodes; obtain the wind resistance coefficient of each differential ventilation duct section in the straight section and the local wind resistance coefficient of each differential ventilation duct section in the bend section.

[0018] Based on the pressure and air volume at the outlet of the working face ventilation duct and the long-distance working face ventilation duct, the static pressure at the previous leakage node is calculated sequentially. This process is repeated to obtain the static pressure at each leakage node in the straight section and the bend section. The calculation formula is as follows:

[0019]

[0020] Among them, P i P represents the static pressure at the i-th leakage node in the straight section; i+1 The static pressure at the (i+1)th leakage node in the straight section; R1 represents the drag coefficient of each differential duct segment in the straight section; Q i This represents the airflow rate from the i-th leakage node to the (i+1)-th leakage node in the straight section; This represents the static pressure at the i-th leakage node in the bend section; R1 represents the static pressure at the (i+1)th leakage node in the bend section; R2 represents the local drag coefficient of each differential air duct segment in the bend section. This represents the airflow from the i-th leakage node to the (i+1)-th leakage node in the bend section;

[0021] Obtain the air leakage resistance coefficient, and calculate the air leakage at each leakage node in the straight and curved sections based on the static pressure and air leakage resistance coefficient. The calculation formula is as follows:

[0022]

[0023] Wherein, △Q i This represents the air leakage at the i-th leakage node in the straight line segment; represents the air leakage at the i-th leakage node in the bend section; r represents the air leakage resistance coefficient;

[0024] The air leakage rate of the electrically controlled damper section is obtained; the air leakage rate of the ventilation duct at the near working face is obtained by adding the air leakage rates of the corresponding straight section, the corner section, and the electrically controlled damper; the air leakage rate of the ventilation duct at the far working face is obtained by adding the air leakage rates of its corresponding straight section and the corner section; the air leakage rate of the main ventilation duct is obtained by adding the air leakage rates of its corresponding straight section.

[0025] Preferably, obtaining the air leakage of the electrically controlled damper section includes:

[0026] The static pressure is calculated sequentially using the static pressure calculation formulas for straight sections and curved sections. The static pressure from the near working face to the downwind section of the electrically controlled damper section is calculated, and the static pressure from the far working face to the upwind section of the electrically controlled damper section is calculated. The pressure difference between the two ends of the electrically controlled damper section is obtained, and the air leakage of the electrically controlled damper section is obtained based on the pressure difference.

[0027] Preferably, adjusting the air volume based on the total air leakage includes:

[0028] Adjust the air compressor speed and the angle of the electric damper according to the total air leakage and the required air volume of the system to supply air to the near and far working surfaces.

[0029] The embodiments of the present invention have at least the following beneficial effects: The ventilation unit of the present invention includes a near-field working face ventilation duct, a far-field working face ventilation duct, and a main ventilation duct. During ventilation, the main ventilation duct is used to ventilate the near-field and far-field working faces. At the same time, an electric damper is installed in the near-field working face ventilation duct, which can adjust the air volume input to the near-field working face in real time, thereby making it easier to control the air supply to the far-field and near-field working faces. The wind speed sensor and methane sensor can monitor the ventilation and pollution conditions in the ventilation system in real time, and then further analyze and accurately adjust the ventilation. At the same time, the leakage measurement unit is used to calculate the leakage of the near-field working face ventilation duct, the far-field working face ventilation duct, and the main ventilation duct, making the measurement of leakage more accurate. The speed of the air compressor and the angle of the electric damper are adjusted according to the total leakage and the required air volume of the system, which can improve the accuracy of air volume control, reduce the energy consumption in the air supply adjustment process, and ensure the temperature and safety of the working environment of the working face. Attached Figure Description

[0030] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a system block diagram of an F-type air duct air volume regulation system with measurable air leakage provided in an embodiment of the present invention;

[0032] Figure 2 This is a schematic diagram of the overall structure of an F-type air duct airflow regulating system with measurable air leakage, provided in an embodiment of the present invention.

[0033] Figure 3 This invention provides a schematic diagram of the airflow regulation principle of an F-type air duct airflow regulation system capable of measuring air leakage.

[0034] Figure 4 This is a schematic diagram of the structure of an electric damper for an F-type air duct airflow regulating system capable of measuring air leakage, provided in an embodiment of the present invention.

[0035] Figure 5 A circuit diagram of a series interlocking device for an F-type air duct air volume regulating system capable of measuring air leakage is provided in an embodiment of the present invention.

[0036] Figure 6 An abstract network diagram of a type F-type duct airflow regulation system with measurable air leakage is provided for an embodiment of the present invention. Detailed Implementation

[0037] To further illustrate the technical means and effects adopted by the present invention to achieve its intended purpose, the following, in conjunction with the accompanying drawings and preferred embodiments, details the specific implementation, structure, features, and effects of an F-type air duct airflow regulation system capable of measuring air leakage according to the present invention. In the following description, different "one embodiment" or "another embodiment" do not necessarily refer to the same embodiment. Furthermore, specific features, structures, or characteristics in one or more embodiments can be combined in any suitable form.

[0038] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0039] The following description, in conjunction with the accompanying drawings, details a specific scheme for an F-type air duct airflow regulation system with measurable air leakage provided by the present invention.

[0040] Example:

[0041] The main application scenario of this invention is as follows: During the construction of tunnels, especially long tunnels at high altitudes, it is even more necessary to ensure good air quality inside the tunnel. Therefore, ventilation ducts should be installed during construction to provide continuous ventilation and forcefully expel the exhaust gas emitted by various construction machinery and equipment and the large amount of dust generated by spraying, so as to ensure good air quality in the tunnel and thus ensure the safety of construction personnel. During the ventilation process, the air leakage of the ventilation duct is one of the key factors in controlling the air volume. Therefore, the measurement of the air leakage of the ventilation duct is also extremely important.

[0042] Please see Figure 1The diagram illustrates a structural schematic of an F-type duct airflow regulation system with measurable air leakage provided by an embodiment of the present invention. The system mainly includes a duct ventilation unit, a data acquisition unit, an air leakage measurement unit, and a ventilation control unit. Figure 1 and Figure 4 The markings for each part are as follows: 1 is the near-field working surface; 2 is the far-field working surface; 3 is the fresh airflow; 4 is the stale airflow; 5 is the electric damper; 6 is the air compressor; 7 is the damper shaft; 8 is the methane sensor T1; 9 is the wind speed sensor C1; 10 is the methane sensor T2; 11 is the wind speed sensor C2; 12 is the air compressor control device; 13 is the first safety monitoring substation; 14 is the second safety monitoring substation; 15 represents the air duct of the entire ventilation system; and 16 is the electric damper controller.

[0043] The ventilation duct unit includes a near-field ventilation duct, a far-field ventilation duct, and a main ventilation duct. The entire ventilation system mainly consists of three ducts. The main ventilation duct is connected to both the near-field and far-field ventilation ducts, forming an F-shaped duct, which constitutes the ventilation duct structure of the entire ventilation system. The ventilation duct unit also includes an air compressor, which is connected to the main ventilation duct to supply air to the entire ventilation system. Its location is as follows... Figure 1 As shown.

[0044] The air compressor includes electrical and transmission components, a compression section, and a cooling section. The motor and control cabinet in the electrical and transmission section have high protection levels and are continuously cooled, ensuring the longest possible service life for each component and increasing the compressor's efficiency. The compression section has a compact structure and is easy to maintain. The compressor head is directly connected to the oil-gas separator via a flange connection. The entire assembly is placed on a shock-resistant base. The direct flange connection between the compressor head and the oil separator avoids the need for hoses connecting to the oil-gas separator. The cooling section's fan and cooler are installed at the top of the system, expelling cooling air to the outside through forced circulation. The clever design of the maintenance cover makes cleaning the cooler very easy and does not require disassembly. The air compressor has a motor, control cabinet, compressor head, oil-gas separator, fan, and cooler. The motor and control cabinet are connected to the compressor, and the fan and cooler are installed at the top of the system. Furthermore, the air duct is highly flexible, low-cost, lightweight, and very convenient to transport.

[0045] The data acquisition unit includes a wind speed sensor and a methane sensor, which are used to collect data. The wind speed sensor is installed at the air outlet of the ventilation duct at the near working face and the ventilation duct at the far working face, respectively. The methane sensor is installed inside the near working face and the far working face, respectively.

[0046] In this embodiment of the invention, there are two wind speed sensors, namely wind speed sensor C1 and wind speed sensor C2, which are used to measure the wind speed at the air outlet of the near-field working face duct and the far-field working face duct, respectively. There are also two methane sensors, namely methane sensor T1 and methane sensor T2, which are used to detect the methane content in the working face. Wind speed sensor C1 is installed at the air outlet of the near-field working face duct, and wind speed sensor C2 is installed at the air outlet of the far-field working face duct. In order to detect the methane content in the working face, the methane sensors need to be installed in the working face. Methane sensor T1 is fixed on the opposite side of the near-field working face air outlet duct, that is, outside the air outlet end, at a distance from the working face within a preset range. Similarly, methane sensor T2 is fixed on the opposite side of the far-field working face air outlet duct, that is, outside the air outlet end, at a distance from the working face within a preset range. Preferably, in this embodiment of the invention, the preset range is within 5m. The implementer can adjust the installation position of the methane sensors according to the actual situation.

[0047] Wind speed sensors C1 and C2 are installed inside the ventilation duct at the near working face and at the far working face, respectively. Methane sensors T1 and T2 are also installed at the near working face and at the far working face, respectively. These sensors can monitor the changes in wind speed and methane levels in the ventilation duct in real time, and then perform further analysis to adjust the ventilation volume in the ventilation duct.

[0048] The data acquisition unit also includes a first safety monitoring substation and a second safety monitoring substation. Wind speed sensor C1 is connected to the first safety monitoring substation, and the first safety monitoring substation is connected to the second safety monitoring substation. Wind speed sensor C2 is connected to the second safety monitoring substation. Methane sensor T1 and methane sensor T2 are respectively connected to the first safety monitoring substation and the second safety monitoring substation.

[0049] The air leakage measurement unit is used to calculate the air leakage of the near-field ventilation duct, the far-field ventilation duct, and the main ventilation duct, and to obtain the total air leakage.

[0050] After the ventilation duct is manufactured, air leakage may occur due to manufacturing process issues or negligence during installation. Therefore, it is necessary to calculate the air leakage rate. Usually, the air leakage rate is calculated based on the standard at the time of manufacture. However, due to many problems in actual application, it is not accurate. Therefore, it is necessary to recalculate the air leakage rate. In this invention, the ventilation duct of the entire ventilation system is divided into three parts: the ventilation duct for the near working face, the ventilation duct for the far working face, and the main ventilation duct. Therefore, it is necessary to calculate the air leakage rate for each of these three parts.

[0051] When calculating the air leakage of the ventilation ducts for the near-field working face, the far-field working face, and the main ventilation duct, the entire ventilation system's ductwork is F-shaped, not a perfectly straight line. Therefore, it needs to be divided into straight sections, curved sections, and electrically operated damper sections for further calculations. Figure 1 As shown, the straight section, bend section, and electrically controlled damper section of the near-distance working face ventilation duct, the far-distance working face ventilation duct, and the main ventilation duct are obtained; wherein the near-distance working face ventilation duct includes one straight section, one bend section, and one electrically controlled damper section; the far-distance working face ventilation duct includes one straight section and one bend section; and the main ventilation duct includes one straight section; based on the obtained straight section, bend section, and electrically controlled damper section of the ventilation duct, the air leakage of the far-distance working face ventilation duct and the main ventilation duct is calculated respectively.

[0052] Simultaneously, the diameter D of the ventilation duct, the length L of each section, the air density, the air pressure and air volume at the outlet are obtained. The air pressure and air volume at the outlet of the ventilation duct at the near working face and the far working face are obtained by direct measurement. The air volume is calculated by combining the wind speed measured by the wind speed sensor with parameters such as the diameter of the ventilation duct itself, while the air pressure is obtained using a Pitot tube.

[0053] Furthermore, according to the law of conservation of air volume, if there is a leak at a point in the ventilation duct, the airflow at that point will split into two directions: one downwards and the other outwards. Taking a straight section as an example, the airflow in the straight section can be abstracted into a ventilation network diagram, such as... Figure 6 As shown, air leakage occurs at each differential node. Therefore, it is necessary to differentiate the straight section and the curved section corresponding to the air duct at the distance from the working face, the air duct at the far distance from the working face, and the main ventilation duct into n equal parts, so as to obtain n differential air duct segments and n air leakage nodes.

[0054] Among them, the corner section and the electric damper section need to be listed separately for calculation to obtain the wind resistance coefficient of each differential wind tunnel section in the straight section and the local wind resistance coefficient of each differential wind tunnel section in the corner section.

[0055] Based on the pressure and air volume at the outlet of the working face ventilation duct and the long-distance working face ventilation duct, the static pressure at the previous leakage node is calculated sequentially. This process is repeated to obtain the static pressure at each leakage node in the straight section and the bend section. The calculation formula is as follows:

[0056]

[0057] Among them, P i P represents the static pressure at the i-th leakage node in the straight section; i+1 The static pressure at the (i+1)th leakage node in the straight section; R1 represents the drag coefficient of each differential duct segment in the straight section, in Ns. 2 / m8 Q i This represents the airflow rate from the i-th leakage node to the (i+1)-th leakage node in the straight section; This represents the static pressure at the i-th leakage node in the bend section; Ri represents the static pressure at the (i+1)th leakage node in the bend section; R2 represents the local drag coefficient of each differential duct segment in the bend section, in Ns. 2 / m 8 ; This represents the airflow from the i-th leakage node to the (i+1)-th leakage node in the bend section;

[0058] It should be noted that the total drag coefficient of each differential duct segment in the bend section needs to be obtained by adding the drag coefficient of each differential duct segment in the straight section and the local drag coefficient of each differential duct segment in the bend section. This is due to its special bend structure. In addition, the drag coefficient of each differential duct segment is determined by the duct's own parameters, such as material, length, and diameter, which can be obtained from the manufacturer's data. The static pressure of each differential node needs to be calculated by working backward from the air pressure of the first differential node at the outlet to obtain the static pressure of each node.

[0059] Obtain the air leakage resistance coefficient, and calculate the air leakage at each leakage node in the straight and curved sections based on the static pressure and air leakage resistance coefficient. The calculation formula is as follows:

[0060]

[0061] Wherein, △Q i This represents the air leakage at the i-th leakage node in the straight line segment; This represents the air leakage at the i-th leakage node in the bend section; r represents the air leakage resistance coefficient, in Ns. 2 / m 8 The air leakage resistance coefficient is determined by the material of the air duct, which needs to be obtained through preliminary research on material and manufacturer information, calculation, and experiments.

[0062] After obtaining the air leakage at each differential node of the straight section and the curved section, it is also necessary to obtain the air leakage of the electrically controlled damper section. The calculation method is the same as that for the straight section and the curved section. Specifically, the electrically controlled damper section is not differentiated again. The static pressure is calculated sequentially according to the static pressure calculation formula of the straight section and the curved section. The static pressure from the near working face to the downwind section of the electrically controlled damper section is calculated, and the static pressure from the far working face to the upwind section of the electrically controlled damper section is calculated. The pressure difference between the two ends of the electrically controlled damper section is obtained, and the air leakage of the electrically controlled damper section is obtained based on the pressure difference.

[0063] For straight sections and curved sections, the leakage of each straight section and the leakage of each curved section can be obtained by adding the leakage of the differential nodes of the straight sections and the curved sections respectively.

[0064] The air leakage of the ventilation duct at the near working face is obtained by adding the air leakage of the corresponding straight section, the air leakage of the corner section, and the air leakage of the electrically controlled damper; the air leakage of the ventilation duct at the far working face is obtained by adding the air leakage of its corresponding straight section and the air leakage of its corner section; the air leakage of the main ventilation duct is the air leakage of its corresponding straight section.

[0065] Thus, the air leakage of the near-field working face ventilation duct, the far-field working face ventilation duct, and the main ventilation duct were obtained respectively, and the total air leakage was obtained by adding them together.

[0066] The ventilation control unit includes an air compressor control device, an electric damper, an electric damper controller, and a data sensor; wherein the electric damper controller is connected to the electric damper and adjusts the air volume based on the total air leakage.

[0067] The ventilation control unit is mainly used to adjust ventilation based on the total air leakage and the air volume required by the ventilation system. The air compressor control device is mechanically connected to the air compressor, and the electric damper is electrically connected to the electric damper controller. A schematic diagram of the electric damper is shown below. Figure 4 As shown, it mainly includes a damper shaft, an electric damper, and an electric damper controller. The electric damper controller controls the start / stop of the damper shaft according to the ventilation requirements, thereby changing the size of the damper's angle and adjusting the airflow.

[0068] The ventilation control unit also includes a first power-off device and a second power-off device. Methane sensors T1 and T2 are connected to the first and second safety monitoring substations, respectively. The first and second safety monitoring substations are connected to the low-voltage feeder switch via the first and second power-off devices, respectively. The low-voltage feeder switch is connected to the air compressor, thus forming a series interlocking device for the air compressor. Figure 5 As shown, when methane sensor T1 or methane sensor T2 detects that the methane concentration at the working face exceeds the limit during the tunneling process, the first power-off device and the second power-off device disconnect the low-voltage feeder switch of the corresponding ventilation fan power supply in the substation where the air compressor's upstream power supply is located, thereby realizing the interlocking power-off of the air compressor and stopping the tunneling work.

[0069] Regarding the adjustment of air volume, when it is necessary to adjust the air volume of the working face, the air supply volume of the air compressor is determined by calculating the air leakage and the air volume required by the system. Then, the speed of the air compressor and the angle of the electronically controlled damper are adjusted to achieve the purpose of regulating the air volume. Here, the air volume required by the system refers to the air volume required under ideal conditions, that is, when the air duct does not leak air.

[0070] The air supply volume of the air compressor is determined by the total air leakage and the required air volume. Once the air supply volume of the air compressor is determined, in order to achieve intelligent control, the opening angle of the electrically controlled damper is adjusted according to the wind speed measured by wind speed sensor C1 and wind speed sensor C2.

[0071] When the system starts up, after the air compressor starts smoothly, the wind speed values ​​measured by wind speed sensors C1 and C2 are converted into electrical signals and sent to the first and second safety monitoring substations respectively. The first and second safety monitoring substations identify the electrical signals. The electric damper is in the closed state, and the air volume at the remote working face is already sufficient. At this time, the second safety monitoring substation sets a first wind speed threshold, which is 1.1 times the wind speed value of the duct required for the working face (the air volume exceeds the required air volume, forming redundancy, which is beneficial to construction safety). If the wind speed is lower than the first wind speed threshold, the electrical signal is immediately transmitted to the electric damper controller to stop the electric damper from changing the damper angle. At the same time, the first safety monitoring substation also sets a second wind speed threshold, which is the minimum wind speed value of the duct required for the working face (the air volume just meets the required air volume at the working face, reducing air volume loss). If the wind speed is higher than the second wind speed threshold, the electrical signal is immediately transmitted to the electric damper controller to stop the electric damper from changing the damper angle.

[0072] When the required airflow is met at the far working face, but the required airflow is not met at the near working face, and the electric damper is fully open, the first safety monitoring substation directly transmits the electrical signal to the second safety monitoring substation. The second safety monitoring substation then transmits the electrical signal to the air compressor control device, which changes the air compressor speed to change the airflow until the required airflow at the near working face is met. At this point, the wind speed sensor C1 transmits the electrical signal to the first safety monitoring substation, which then transmits the signal to the second safety monitoring substation. Finally, the second safety monitoring substation 14 transmits the electrical signal to the air compressor control device, stopping the change of the air compressor speed.

[0073] When the air compressor's speed is stable, its air delivery volume must not be less than the sum of the total air leakage and the system's required air volume. The first and second wind speed thresholds need to be set based on the air leakage and required air volume of the ventilation ducts near and far from the working face, ensuring the safety of the construction environment within the working face. The air compressor control device can automatically adjust the diesel engine speed according to the exhaust pressure, ensuring the diesel engine operates at its optimal, fuel-efficient speed. It outputs a PWM signal to control the proportional solenoid valve, thereby controlling the intake pressure. The system has a low failure rate, long service life, and is conducive to widespread adoption.

[0074] It should be noted that the order of the above embodiments of the present invention is merely for descriptive purposes and does not represent the superiority or inferiority of the embodiments. Furthermore, the above description focuses on specific embodiments of this specification. Additionally, the processes depicted in the accompanying drawings do not necessarily require a specific or sequential order to achieve the desired results. In some embodiments, multitasking and parallel processing are possible or may be advantageous.

[0075] The various embodiments in this specification are described in a progressive manner. The same or similar parts between the various embodiments can be referred to each other. Each embodiment focuses on describing the differences from other embodiments.

[0076] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. An F-type air duct airflow regulation system with measurable air leakage, characterized in that, The system includes: a ventilation duct unit, a data acquisition unit, a leakage measurement unit, and a ventilation control unit; The ventilation unit includes a near-field working face ventilation duct, a far-field working face ventilation duct, and a main ventilation duct; the near-field working face ventilation duct and the far-field working face ventilation duct are respectively connected to the main ventilation duct to form an F-shaped ventilation duct; the ventilation unit also includes an air compressor, which is connected to the main ventilation duct and used to deliver air volume; The data acquisition unit includes a wind speed sensor and a methane sensor, which are used to collect data. The wind speed sensor is installed at the air outlet of the air duct at the near working face and the air duct at the far working face, respectively. The methane sensor is installed inside the near working face and the far working face, respectively. The air leakage measurement unit is used to calculate the air leakage of the near-distance working face ventilation duct, the far-distance working face ventilation duct and the main ventilation duct, and obtain the total air leakage. The ventilation control unit includes an air compressor control device, an electric damper, an electric damper controller, and a data sensor; wherein the electric damper controller is connected to the electric damper and adjusts the air volume based on the total air leakage. The calculation of air leakage for the near-field ventilation duct, the far-field ventilation duct, and the main ventilation duct includes: Obtain the straight section, bend section, and electrically controlled damper section of the near-distance working face ventilation duct, the far-distance working face ventilation duct, and the main ventilation duct; wherein the near-distance working face ventilation duct includes one straight section, one bend section, and one electrically controlled damper section; the far-distance working face ventilation duct includes one straight section and one bend section; and the main ventilation duct includes one straight section; calculate the air leakage of the ventilation duct at the distance from the working face ventilation duct, the far-distance working face ventilation duct, and the main ventilation duct based on the obtained straight section, bend section, and electrically controlled damper section; Based on the obtained data for the straight section, curved section, and electrically controlled damper section of the ventilation duct, the air leakage rates at the distance to the working face ventilation duct, the long-distance working face ventilation duct, and the main ventilation duct are calculated, including: Divide the straight sections and bend sections corresponding to the ventilation ducts at the distance from the working face, the long-distance working face, and the main ventilation duct into n equal parts to obtain n differential ventilation duct sections and n leakage nodes; obtain the wind resistance coefficient of each differential ventilation duct section in the straight section and the local wind resistance coefficient of each differential ventilation duct section in the bend section. Based on the pressure and air volume at the outlet of the working face ventilation duct and the long-distance working face ventilation duct, the static pressure at the previous leakage node is calculated sequentially. This process is repeated to obtain the static pressure at each leakage node in the straight section and the bend section. The calculation formula is as follows: ， ； in, This represents the static pressure at the i-th leakage node in the straight section; The static pressure at the (i+1)th leakage node in the straight section; This represents the drag coefficient of each differential section of the duct within the straight section; This represents the airflow rate from the i-th leakage node to the (i+1)-th leakage node in the straight section; This represents the static pressure at the i-th leakage node in the bend section; This represents the static pressure at the (i+1)th leakage node in the bend section; This represents the local drag coefficient of each differential section of the ventilation duct in the bend section; This represents the airflow from the i-th leakage node to the (i+1)-th leakage node in the bend section; Obtain the air leakage resistance coefficient, and calculate the air leakage at each leakage node in the straight and curved sections based on the static pressure and air leakage resistance coefficient. The calculation formula is as follows: ； ； in, This represents the air leakage at the i-th leakage node in the straight line segment; represents the air leakage at the i-th leakage node in the bend section; r represents the air leakage resistance coefficient; The air leakage rate of the electrically controlled damper section is obtained; the air leakage rate of the ventilation duct at the near working face is obtained by adding the air leakage rates of the corresponding straight section, the corner section, and the electrically controlled damper; the air leakage rate of the ventilation duct at the far working face is obtained by adding the air leakage rates of its corresponding straight section and the corner section; the air leakage rate of the main ventilation duct is obtained by adding the air leakage rates of its corresponding straight section.

2. The F-type air duct airflow regulating system with measurable air leakage as described in claim 1, characterized in that, The wind speed sensor and methane sensor include wind speed sensor C1 and wind speed sensor C2, respectively. Anemometer C1 is installed at the air outlet of the ventilation duct at the near working face; anemometer C2 is installed at the air outlet of the ventilation duct at the far working face; methane sensors include methane sensor T1 and methane sensor T2. Methane sensor T1 is installed outside the air outlet of the ventilation duct at the near working face, at a distance from the working face within a preset range; methane sensor T2 is installed outside the air outlet of the ventilation duct at the far working face, at a distance from the working face within a preset range.

3. The F-type air duct airflow regulating system with measurable air leakage as described in claim 1, characterized in that, The data acquisition unit also includes a first safety monitoring substation and a second safety monitoring substation; wind speed sensor C1 is connected to the first safety monitoring substation, and the first safety monitoring substation is connected to the second safety monitoring substation; wind speed sensor C2 is connected to the second safety monitoring substation; the second safety monitoring substation is connected to the electric damper controller and the air compressor control device respectively.

4. The F-type air duct airflow regulating system with measurable air leakage as described in claim 1, characterized in that, The air compressor control device is mechanically connected to the air compressor, and the electric damper is electrically connected to the electric damper controller.

5. The F-type air duct airflow regulating system with measurable air leakage as described in claim 1, characterized in that, The ventilation control unit also includes a first power-off device and a second power-off device; methane sensor T1 and methane sensor T2 are respectively connected to the first safety monitoring substation and the second safety monitoring substation; the first safety monitoring substation and the second safety monitoring substation are respectively connected to the low-voltage power supply switch through the first power-off device and the second power-off device, and the low-voltage power supply switch is connected to the air compressor.

6. The F-type air duct airflow regulating system with measurable air leakage as described in claim 1, characterized in that, The acquisition of the air leakage rate of the electrically controlled damper section includes: The static pressure is calculated sequentially using the static pressure calculation formulas for straight sections and curved sections. The static pressure from the near working face to the downwind section of the electrically controlled damper section is calculated, and the static pressure from the far working face to the upwind section of the electrically controlled damper section is calculated. The pressure difference between the two ends of the electrically controlled damper section is obtained, and the air leakage of the electrically controlled damper section is obtained based on the pressure difference.

7. The F-type air duct airflow regulating system with measurable air leakage as described in claim 1, characterized in that, The adjustment of air volume based on the total air leakage includes: Adjust the air compressor speed and the angle of the electric damper according to the total air leakage and the required air volume of the system to supply air to the near and far working surfaces.

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