Mobile cooling device for high-temperature mine driving working face and control method of mobile cooling device

Abstract

The invention discloses a mobile cooling device for a high-temperature mine driving working face and a control method thereof, and belongs to the technical field of mine cooling. In order to solve the problems that existing equipment is high in energy consumption, large in size and the like, the device comprises a movable chassis, and an air duct, a frequency conversion fan, a coiled tube heat exchanger, a liquid CO2 storage tank and an intelligent control unit which are carried by the movable chassis. According to the method, a cascade heat control strategy of air first and then cooling is established; an intelligent control unit monitors the air temperature in real time, and a frequency conversion fan is preferentially adjusted to carry out basic air volume heat control; and when the air temperature exceeds the limit and air control fails, the control valve is opened according to the proportion, and liquid CO2 serves as an auxiliary phase change cold source to be injected into the heat exchanger pipe. Liquid CO2 in the pipe and hot air outside the pipe form countercurrent indirect heat exchange, and gasified waste gas is discharged into an air return side through a bottom exhaust pipe in a back-to-back manner. Air cooling self-adaptive coupling is achieved, the energy consumption and the size of the system are greatly reduced, and the heat exchange efficiency and the operation safety are guaranteed through closed countercurrent exhaust.

Description

Technical Field

[0001] This invention belongs to the field of mine cooling and emergency ventilation technology, and specifically relates to a mobile cooling device for high-temperature mine tunneling faces and its control method. Background Technology

[0002] With the development of my country's mining industry, shallow coal resources are gradually decreasing or even depleting. Underground mining depths are increasing, leading to a rise in the number of high-temperature mines, especially in poorly ventilated tunneling faces where temperatures can reach as high as 40°C, making mine heat hazards increasingly prominent. High-temperature environments cause significant physical and psychological harm to underground workers, such as tachycardia, fatigue, and difficulty concentrating. Furthermore, they hinder the heat dissipation of mechanical equipment, accelerating its aging and significantly increasing the accident rate. Traditional ventilation and cooling methods are insufficient to address the current heat hazards in deep mines. To solve this problem, existing technologies often employ mechanical circulating refrigeration equipment consisting of a compressor, condenser, and evaporator. However, traditional mechanical refrigeration equipment has several significant drawbacks: firstly, it requires a large amount of electricity to drive the compressor, significantly increasing energy consumption; secondly, the units are bulky and have complex pipelines, making rapid movement and deployment difficult in confined and constantly advancing tunneling faces; and finally, in extreme areas with high methane concentrations or limited power supply, the safety and applicability of large-scale electrical refrigeration equipment are greatly compromised. Designing a portable cooling device that is simple in structure, low in energy consumption, and capable of coping with localized extreme heat damage is a technical challenge that urgently needs to be solved. Summary of the Invention

[0003] To address the problems of large size, high energy consumption, and difficulty in movement associated with existing mechanical refrigeration technologies, this invention aims to provide a mobile cooling device and its control method for high-temperature mine tunneling faces. This invention abandons the traditional mechanical compression refrigeration cycle and adopts a gradient heat control strategy that couples airflow regulation with liquid refrigerant phase change, achieving miniaturization and high efficiency of the cooling equipment.

[0004] The technical solution of the present invention is: a mobile cooling device for high-temperature mine tunneling face and its control method, comprising: a mobile chassis (1), a ventilation duct (2), a variable frequency speed control fan (3), a coiled tube heat exchanger (4), a high-pressure liquid carbon dioxide storage tank (5), a proportional control valve (6), a gaseous carbon dioxide collection manifold (7), an exhaust pipe (8), a temperature sensor (9), and an intelligent control unit (10).

[0005] Another technical solution of the present invention is: a control method for the above-mentioned mobile cooling device for high-temperature mine tunneling faces, comprising the following steps: acquiring the ambient wind temperature T in real time; and, based on the acquired wind temperature T, controlling the power supply frequency of the variable frequency speed-regulating fan and the opening degree of the proportional control valve in a cascade linkage manner to achieve adaptive switching between air volume heat control and liquid refrigerant phase change heat absorption.

[0006] A ventilation duct (2) is fixedly installed on the upper part of the mobile chassis (1). A coiled tube heat exchanger (4) is provided axially inside the ventilation duct (2). A variable frequency speed control fan (3) is installed at the air inlet end of the ventilation duct (2). The high-pressure liquid carbon dioxide storage tank (5) is located on the mobile chassis (1). Its output end is connected to the liquid inlet end of the coiled tube heat exchanger (4) through a pipeline and a proportional control valve (6). The gas outlet end of the coiled tube heat exchanger (4) is connected to a gaseous carbon dioxide collection manifold (7). An exhaust pipe (8) is connected to the gaseous carbon dioxide collection manifold (7). The temperature sensor (9) is located at the air outlet end of the ventilation duct (2) or at the end of the tunneling face. The intelligent control unit (10) is electrically connected to the variable frequency speed control fan (3), the proportional control valve (6), and the temperature sensor (9).

[0007] The beneficial effects of this invention are as follows: 1. Gradient heat control significantly reduces energy consumption: This invention establishes a tiered cooling logic of "air-controlled heat as the primary method and phase-change heat control as a secondary method." Under normal heat hazards, heat is removed by adjusting the airflow of the variable frequency fan; under extreme high temperatures where air control fails, liquid carbon dioxide phase-change heat absorption is instantly activated, avoiding continuous ineffective high-energy-consumption operation of the refrigeration equipment; 2. Extremely simplified structure and high mobility: This system replaces the bulky compressor, condenser and cold water tank in traditional cooling equipment with a high-pressure liquid carbon dioxide storage tank, which can be flexibly moved forward as the tunneling face advances, making it extremely suitable for complex and narrow mine roadways. 3. Counter-current heat exchange design for high cooling efficiency: Liquid carbon dioxide is injected from the end of the tube near the working surface and flows backward, forming a counter-current flow with the high-temperature fresh air blown towards the working surface inside the air duct. Counter-current heat exchange maintains a large temperature difference along the process, effectively preventing icing and blockage caused by localized extremely low temperatures in the heat exchanger, and significantly improving cooling efficiency. 4. Backward settling exhaust ensures construction safety: The gasified carbon dioxide exhaust gas has a high density. This system cleverly incorporates a bottom-mounted backward settling exhaust pipe. The exhaust gas is discharged close to the ground, away from the tunnel face, into the return airway. This not only lowers the overall center of gravity but also fundamentally eliminates the problem of "recirculated exhaust gas" from local fans, preventing carbon dioxide poisoning and suffocation among workers at the face. Attached Figure Description

[0008] To more clearly illustrate the technical solutions and advantages in the embodiments of the present invention or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below. The accompanying drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0009] Figure 1 Flowchart of a moving cooling device and its control method for a high-temperature mine tunneling face according to one embodiment of the present invention.

[0010] Figure 2 This is a schematic diagram of the overall structure of a mobile cooling device for a high-temperature mine tunneling face, provided in an embodiment of the present invention.

[0011] The attached diagram is labeled as follows: 1. Mobile chassis, 2. Ventilation duct, 3. Variable frequency speed control fan, 4. Wound tube heat exchanger, 5. High-pressure liquid carbon dioxide storage tank, 6. Proportional control valve, 7. Gaseous carbon dioxide collection manifold, 8. Exhaust gas pipe, 9. Temperature sensor, 10. Intelligent control unit. Detailed Implementation

[0012] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0013] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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, they should not be construed as limitations on this invention.

[0014] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0015] See Figure 1This invention provides a mobile cooling device and its control method for a high-temperature mine tunneling face, comprising a mobile chassis (1). Specifically, the bottom of the mobile chassis (1) is symmetrically equipped with track wheels or track mechanisms suitable for movement within the mine roadway. Furthermore, the core cooling system of this invention is mounted on top of the mobile chassis (1), making the entire system a mobile unit that can advance with the tunneling face.

[0016] Specifically, the core cooling system is structurally divided into a high-velocity air heat exchange channel and a refrigerant storage and supply area. The air heat exchange channel includes a ventilation duct (2) fixedly installed on the upper part of the mobile chassis (1). A variable frequency speed-regulating fan (3) is installed at the air inlet end of the ventilation duct (2), which is used to forcibly draw in fresh air from behind the roadway and blow it forward toward the tunneling face. Furthermore, a coiled tube heat exchanger (4) is provided axially inside the ventilation duct (2) as the core component for heat exchange.

[0017] In this embodiment, the refrigerant storage and supply area includes a high-pressure liquid carbon dioxide storage tank (5) mounted on the mobile chassis (1). Specifically, the high-pressure liquid carbon dioxide storage tank (5) stores high-pressure liquid carbon dioxide as the sole cold source for the system's phase change heat absorption. Preferably, to achieve efficient counter-current heat exchange between the refrigerant and the airflow, the output end of the high-pressure liquid carbon dioxide storage tank (5) is connected to a proportional control valve (6) via a pipeline, and the other end of the proportional control valve (6) is connected to the liquid inlet end of the coiled tube heat exchanger (4) near the air outlet of the ventilation duct (2) (i.e., the front end). A gaseous carbon dioxide collection manifold (7) is connected to the side of the coiled tube heat exchanger (4) away from the liquid inlet end. The above structure makes the flow direction of the liquid carbon dioxide in the heat exchanger tube strictly opposite to the high-temperature airflow direction inside the ventilation duct (2) but outside the heat exchanger tube. The two do not come into contact with each other and conduct indirect heat exchange through the heat exchanger tube wall in a counter-current manner, avoiding the defect of reduced temperature difference at the end of the co-current heat exchange and greatly improving the heat exchange efficiency.

[0018] Furthermore, the gaseous carbon dioxide collection manifold (7) is externally connected to an exhaust pipe (8). To ensure operational safety, the exhaust pipe (8) extends downwards from the gaseous carbon dioxide collection manifold (7) and is arranged close to the ground, with its exhaust outlet facing away from the return airway side of the tunneling face. This design fully utilizes the natural settling effect of carbon dioxide exhaust gas having a density greater than that of air, preventing the exhaust gas from diffusing into the upper working space or being drawn back into the variable frequency speed-regulating fan (3).

[0019] Furthermore, in order to achieve intelligent tiered cooling, the intelligent control unit (10) acquires the ambient wind temperature (T) in real time through the temperature sensor (9) arranged at the end of the tunnel face or the air outlet of the ventilation duct (2). The intelligent control unit (10) has a built-in logic program, and the specific execution steps are as follows: (1) Level 1 wind control thermal mode: When T < 26℃, the intelligent control unit (10) controls the proportional control valve (6) to be in the closed state. At the same time, it controls the variable frequency speed regulating fan (3) to operate at low frequency to provide basic fresh air supply, and the system operates with the lowest energy consumption; (2) Secondary wind control heat enhancement mode: When 26℃ ≤ T<30℃, the intelligent control unit (10) increases the power supply frequency of the variable frequency speed regulating fan (3) to accelerate it to full load and use a large air volume to forcibly remove the heat from the tunneling face; (3) Three-stage phase change assisted cooling mode: When extreme heat damage occurs, T ≥ 30℃ (or the temperature does not show a downward trend after the variable frequency speed control fan (3) has been running at full load for a set time), the single wind control heat failure is determined. The intelligent control unit (10) issues an instruction to open the proportional control valve (6) proportionally while keeping the fan running at full load. At this time, liquid carbon dioxide enters the closed pipe inside the coiled tube heat exchanger (4) and uses the latent heat of vaporization to instantly absorb the heat of the hot air passing through the air duct through the pipe wall. After the temperature drops, the system automatically exits this mode and cuts off the refrigerant consumption.

[0020] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A mobile cooling device for high-temperature mine tunneling faces, characterized in that, include: Mobile chassis (1), ventilation duct (2), variable frequency speed control fan (3), coiled tube heat exchanger (4), high pressure liquid carbon dioxide storage tank (5), proportional control valve (6), gaseous carbon dioxide collection manifold (7), exhaust pipe (8), temperature sensor (9), and intelligent control unit (10). The mobile chassis (1) is fixedly installed with a ventilation duct (2), and a spiral heat exchanger (4) is provided inside the ventilation duct (2) along the axial direction. A variable frequency speed control fan (3) is installed at the air inlet end of the ventilation duct (2). The high-pressure liquid carbon dioxide storage tank (5) is mounted on the mobile chassis (1), and its output end is connected to the liquid inlet end of the coiled tube heat exchanger (4) through a pipeline and the proportional control valve (6); the gas outlet end of the coiled tube heat exchanger (4) is connected to a gaseous carbon dioxide collection manifold (7), and the gaseous carbon dioxide collection manifold (7) is connected to an exhaust pipe (8). The temperature sensor (9) is located at the air outlet of the ventilation duct (2) or at the end of the tunneling face; the intelligent control unit (10) is electrically connected to the variable frequency speed control fan (3), the proportional control valve (6) and the temperature sensor (9).

2. The mobile cooling device for high-temperature mine tunneling faces according to claim 1, characterized in that, The liquid inlet of the coiled tube heat exchanger (4) is located on the side near the air outlet of the ventilation duct (2), and the gaseous carbon dioxide collection manifold (7) is located on the side near the air inlet of the ventilation duct (2), so that the flow direction of the liquid carbon dioxide injected inside is opposite to the flow direction of the high-temperature airflow in the ventilation duct (2), forming a countercurrent heat exchange structure.

3. The mobile cooling device for high-temperature mine tunneling faces according to claim 1, characterized in that, The exhaust pipe (8) extends downward to the ground after being led out from the gaseous carbon dioxide collection manifold (7), and its exhaust port faces away from the tunneling face and points towards the return airway of the mine.

4. The mobile cooling device for high-temperature mine tunneling faces according to claim 1, characterized in that, The intelligent control unit (10) has a built-in cascade heat control strategy program that links air and cooling, and the specific control logic is as follows: When the temperature sensor (9) detects a temperature T < 26℃, the intelligent control unit (10) controls the proportional control valve (6) to close and controls the variable frequency speed control fan (3) to be in a low-frequency energy-saving operation state. When 26℃ ≤ T < 30℃, the intelligent control unit (10) controls the proportional control valve (6) to close and controls the variable frequency speed regulating fan (3) to be raised to full-load high-frequency operation state; When T ≥ 30℃, or when the temperature does not drop after the variable frequency speed control fan (3) has been running at full load for a set time, the intelligent control unit (10) keeps the variable frequency speed control fan (3) running at full load and opens the proportional control valve (6) proportionally to inject liquid carbon dioxide into the coiled tube heat exchanger (4) for phase change-assisted cooling.

5. A mobile cooling device for high-temperature mine tunneling faces according to claim 1, characterized in that, The bottom of the mobile chassis (1) is symmetrically equipped with track wheels or track mechanisms suitable for traveling in mine roadways.

6. A control method for a moving cooling device for high-temperature mine tunneling faces according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1. Real-time monitoring: The ambient wind temperature data T is obtained in real time by temperature sensors (9) arranged at the air outlet of the ventilation duct (2) or at the end of the tunneling face, and the signal is transmitted to the intelligent control unit (10). S2, cascade judgment and linkage control: The intelligent control unit (10) executes the air-cooling adaptive cascade heat control strategy according to the obtained air temperature T, and links and adjusts the operating frequency of the variable frequency speed control fan (3) and the opening degree of the proportional control valve (6).

7. The control method according to claim 6, characterized in that, The air-cooled adaptive cascade heat control strategy in step S2 specifically includes: Level 1 wind control heat mode: When T < 26℃, the intelligent control unit (10) controls the proportional control valve (6) to close and controls the variable frequency speed control fan (3) to operate at low frequency; Secondary wind control heat enhancement mode: When 26℃ ≤ T < 30℃, the intelligent control unit (10) controls the proportional control valve (6) to remain closed and increases the power supply frequency of the variable frequency speed control fan (3) to make it run at full load; Three-stage phase change assisted cooling mode: When T ≥ 30℃, or when the temperature still does not drop after the variable frequency speed control fan (3) has been running at full load for a set time, the intelligent control unit (10) keeps the variable frequency speed control fan (3) running at full load and opens the proportional control valve (6) proportionally to inject liquid carbon dioxide into the tube of the coiled tube heat exchanger (4). The liquid carbon dioxide in the tube and the airflow outside the tube exchange heat in a countercurrent manner. The gasified exhaust gas is discharged into the return air side through the exhaust gas exhaust pipe (8) in the opposite direction.

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