A mine-used liquid CO2 fire extinguishing and intelligent anti-freezing protection system with gas-liquid phase change heat compensation function

Abstract

The present application relates to mine fire prevention and extinguishing technical field, specifically relates to a kind of mine liquid CO2 fire prevention and extinguishing intelligent antifreeze protection system with gas-liquid phase change heat compensation function;Including: casing pipe type heat compensation pipeline module and phase change energy storage buffer module, coaxial air curtain antifreeze injection module, cold recovery and intelligent linkage module.The present application introduces mine waste heat as active heat compensation source by casing pipe type structure, combined with the solidification latent heat released by phase change energy storage module, effectively maintains the working temperature of delivery pipeline under the premise of not using electric heat tracing, eliminates underground electrical explosion hazard;While the coaxial air curtain antifreeze injection module at the end uses pure mechanical cascade valve to synchronously excite fluid medium to form forward convergent physical isolation layer, effectively restricts the ultra-low temperature center jet and prevents it from spreading to operators, avoids personnel frostbite and equipment freezing jam.

Description

Technical Field

[0001] This invention relates to the field of mine fire prevention and extinguishing technology, specifically to a mine-use liquid CO2 fire prevention and extinguishing intelligent antifreeze protection system with gas-liquid phase change heat compensation function. Background Technology

[0002] Liquid carbon dioxide fire suppression technology has been widely used in underground coal mine fire prevention and control due to its high extinguishing efficiency and lack of secondary pollution. However, in the engineering practice of long-distance underground transportation and terminal injection operations of liquid carbon dioxide, severe thermodynamic problems arising from extremely low temperatures are encountered.

[0003] In pipeline transportation, due to the long underground transport distance, there is a significant thermodynamic gradient between the cryogenic liquid carbon dioxide inside the pipe and the external environment. Existing pipelines mostly employ passive insulation structures with added polyurethane or similar materials. This passive insulation method only slows down the rate of heat exchange and cannot fundamentally provide reverse heat flux compensation. As the transport time increases, the pipe wall temperature inevitably drops below the dew point and freezing point, leading to severe condensation and icing on the outer wall, which in turn causes low-temperature embrittlement of the pipe material and damage to the supporting structure. If traditional electric heating tape is used for active heating, the complex environment of high gas and high dust levels in underground coal mines poses a serious safety hazard, potentially causing electrical sparks and explosions.

[0004] During the terminal injection operation, liquid carbon dioxide undergoes a violent throttling expansion and gas-liquid phase change process when ejected from the nozzle, absorbing a large amount of ambient heat in a very short time. Existing conventional nozzles have a simple structure, and the ejected ultra-low temperature carbon dioxide jet comes into direct contact with the external environment and diffuses in a divergent manner. In the enclosed or semi-enclosed working space of a mine, this ultra-low temperature airflow, lacking physical constraints, can easily flow backward or escape towards the area where the operators are located, posing a serious threat of frostbite to the operators; at the same time, the instantaneous extreme temperature drop can also easily cause mechanical actuators such as injection valves to freeze and become stuck.

[0005] Furthermore, existing systems often directly discharge the enormous amounts of waste heat generated during the maintenance and vaporization of carbon dioxide in the pipeline into the underground space. This not only exacerbates the low-temperature hazards of the local pipeline network, but also results in the waste of a large amount of potential cooling resources that could be used for cooling underground electromechanical chambers or personnel, failing to achieve effective cascade utilization of energy. Summary of the Invention

[0006] To achieve the above objectives, the present invention provides a mine-use liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function, comprising:

[0007] (1) A sleeve-type thermal compensation pipeline module, including an inner pipe, an outer pipe and a thermally conductive intermediate layer between the two; the inner pipe is used to transport liquid CO2, the outer pipe is used to transport circulating hot fluid, and the heat of the circulating hot fluid is conducted to the inner pipe through the thermally conductive intermediate layer.

[0008] (2) A phase change energy storage buffer module is set at the node of the sleeve-type heat compensation pipeline module and is filled with phase change material. The phase change material is used to compensate the temperature of the sleeve-type heat compensation pipeline module by utilizing the latent heat of phase change.

[0009] (3) Coaxial air curtain antifreeze spray module, which is located at the end of the sleeve-type heat compensation pipeline module, includes a central spray hole connected to the inner pipe and an annular spray hole surrounding the central spray hole; the annular spray hole is used to synchronously spray fluid medium to form a physical isolation layer that wraps around the central CO2 jet.

[0010] (4) Cold energy recovery and intelligent linkage module, including heat exchanger and sensor group; the heat exchanger is used to recover the cold energy generated by CO2 vaporization and output it to the cooling target area; the sensor group is used to monitor the environmental and personnel status, and thereby control the operation status of the sleeve-type heat compensation pipeline module and the coaxial air curtain antifreeze spray module.

[0011] Furthermore, the medium filled in the thermally conductive intermediate layer is graphene thermally conductive silicone.

[0012] The circulating hot fluid transported in the outer pipe is antifreeze, and the antifreeze is an ethylene glycol solution with a temperature maintained at 15℃-25℃.

[0013] Furthermore, the inlet end of the outer pipe is connected to the mine heat source extraction system, which is used to collect geothermal energy or waste heat from the air compressor and exchange the heat from the geothermal energy or waste heat from the air compressor into the circulating heat fluid.

[0014] A coaxial positioning assembly is provided between the outer wall of the inner tube and the inner wall of the outer tube; the coaxial positioning assembly includes a plurality of thermally conductive support rings spaced apart along the axial direction of the inner tube, and the thermally conductive support rings are provided with through holes for the thermally conductive intermediate layer medium to pass through and fill.

[0015] Furthermore, the phase change energy storage buffer module includes an energy storage shell sleeved outside the key nodes of the sleeve-type thermal compensation pipeline module, and the energy storage shell and the outermost pipe wall of the sleeve-type thermal compensation pipeline module form a closed energy storage chamber; the phase change material is filled in the energy storage chamber; the key nodes include pipeline branches and the front side of the injection operation end;

[0016] The energy storage chamber is also equipped with a three-dimensional thermally conductive skeleton, which is composed of several high thermal conductivity fins connected in an alternating manner; the root of the high thermal conductivity fins is thermally connected to the outer wall of the sleeve-type thermal compensation pipeline module, and the extended end of the high thermal conductivity fins is inserted and immersed in the phase change material.

[0017] Furthermore, the phase change material is a paraffin or brine compound with a specific melting point and a phase change temperature between 2°C and 8°C.

[0018] The phase change material is configured for reversible phase change operation: when liquid CO2 is transported inside the sleeve-type heat compensation pipeline module, causing the surrounding temperature to drop, the phase change material solidifies from liquid to solid to release the latent heat of solidification; when the system stops spraying and the ambient temperature rises, the phase change material absorbs ambient heat and melts from solid to liquid to store heat.

[0019] Furthermore, the coaxial air curtain antifreeze spray module includes a central spray pipe and an outer shroud arranged coaxially and nested together; the front end of the central spray pipe is provided with a plurality of central spray holes arranged in a matrix or quincunx pattern; an annular flow channel is formed between the outer wall of the central spray pipe and the inner wall of the outer shroud, and the front end of the annular flow channel contracts to form the annular spray holes.

[0020] The jet axis of the annular nozzle forms a forward angle of 5° to 15° with the main jet axis of the central nozzle, so that the fluid medium ejected from the annular nozzle can form a conical physical isolation layer with a forward converging tendency around the central CO2 jet.

[0021] Furthermore, the side wall of the outer shroud is provided with a fluid inlet interface, which is connected to the annular flow channel; the fluid inlet interface is connected to the existing compressed air system pipeline or dustproof water supply pipeline in the mine through a quick-connect hose to obtain normal temperature high-pressure air or dustproof water as the fluid medium;

[0022] A double-acting linkage valve is provided at the rear handle of the coaxial air curtain antifreeze spray module; the double-acting linkage valve is configured as a purely mechanical linkage structure: when the operating handle is pressed, the fluid inlet interface is first opened to activate the outer physical isolation layer, and then the inner tube is opened to spray liquid CO2 as the handle continues to press down.

[0023] Furthermore, the heat exchanger is a vaporization endothermic heat exchanger, located at the junction of the main output line of the liquid CO2 storage tank area and the shell-and-tube heat compensation pipeline module; the cold output side of the vaporization endothermic heat exchanger is connected to the air conditioning system of the underground electromechanical chamber or the cold source supply station of the personnel cooling suit through an insulated circulation pipeline, which is used to convert the waste cold generated during the vaporization of CO2 into an environmental cooling source.

[0024] Furthermore, the sensor group includes an intrinsically safe infrared thermal imaging sensor attached to the outer wall of the sleeve-type thermal compensation pipeline module, and an intrinsically safe microwave induction sensor deployed in the operating area of ​​the coaxial air curtain antifreeze spray module.

[0025] The cold energy recovery and intelligent linkage module also includes a mining explosion-proof programmable logic controller that is connected to the sensor group.

[0026] Furthermore, the mining explosion-proof programmable logic controller has a built-in hierarchical linkage control module based on hardware status, including:

[0027] Cold energy recovery priority mode: When the intrinsically safe microwave sensor does not detect the approach of personnel, the circulating hot fluid in the outer tube is stopped, and the cold energy collection loop of the heat exchanger is opened to the maximum extent.

[0028] Personnel protection priority mode: When the intrinsically safe microwave sensor detects personnel approaching and the intrinsically safe infrared thermal imaging sensor detects that the temperature of the outer wall of the pipeline is lower than the preset anti-freezing threshold, the antifreeze circulation pump connected to the outer pipe is automatically started for active heating.

[0029] Forced isolation mode: When the system receives a fire extinguishing spray trigger signal, it forcibly opens the fluid spray valve of the coaxial air curtain antifreeze spray module, so that the physical isolation layer is generated synchronously with the central CO2 jet.

[0030] Beneficial effects

[0031] This invention introduces waste heat from the mine as an active heat compensation source through a sleeve-type structure. Combined with the latent heat of condensation released by the phase change energy storage module, it effectively maintains the working temperature of the delivery pipeline without the need for electric heat tracing, eliminating potential electrical explosion hazards underground. Simultaneously, the coaxial air curtain antifreeze spray module at the end uses purely mechanical cascaded valves to synchronously stimulate the fluid medium to form a forward-converging physical isolation layer, effectively constraining the ultra-low temperature central jet and preventing it from spreading to operators, avoiding frostbite and equipment freezing and jamming. The system converts the vaporized waste heat of carbon dioxide into an environmental cooling source through a cold energy recovery module, achieving a cascaded energy recovery and safety protection, significantly improving the operational safety, reliability, and energy efficiency of the mine liquid carbon dioxide fire extinguishing system. Attached Figure Description

[0032] Figure 1 This is a system diagram of an intelligent antifreeze protection system for mine liquid CO2 fire prevention and extinguishing with gas-liquid phase change heat compensation function according to the present invention.

[0033] Figure 2This is a schematic diagram of the coaxial air curtain antifreeze spray module of a mine liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function according to the present invention.

[0034] Figure 3 This is a schematic diagram of the sleeve-type heat compensation pipeline module structure of a mine liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function according to the present invention.

[0035] Figure 4 This is a schematic diagram of the phase change energy storage buffer module of a mine liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function according to the present invention.

[0036] Figure 5 This is a three-dimensional schematic diagram of the overall system layout of a mine-use liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function according to the present invention.

[0037] Figure 6 This is a schematic diagram of the inner part of the outer pipe (5) of the intelligent antifreeze protection system for fire prevention and extinguishing of liquid CO2 in mines with gas-liquid phase change heat compensation function according to the present invention.

[0038] Reference numerals: 1. Central jet pipe; 2. Double-acting linkage valve; 3. Thermally conductive support ring; 4. Thermally conductive intermediate layer; 5. Outer pipe; 6. Intrinsically safe; 7. Inner pipe; 8. Three-dimensional thermally conductive skeleton (8); 9. Energy storage shell; 10. Phase change material; 11. Heat exchanger; 12. Sensor. Detailed Implementation

[0039] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0040] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0041] The present invention will now be described in further detail with reference to the accompanying drawings:

[0042] Example:

[0043] like Figure 1-6 As shown, this invention provides a smart antifreeze protection system for mine liquid CO2 fire prevention and extinguishing with gas-liquid phase change heat compensation function, comprising:

[0044] (1) A sleeve-type thermal compensation pipeline module, including an inner pipe 7, an outer pipe 5 and a thermally conductive intermediate layer 4 located between the two; the inner pipe 7 is used to transport liquid CO2, the outer pipe 5 is used to transport circulating hot fluid, and the heat of the circulating hot fluid is conducted to the inner pipe 7 through the thermally conductive intermediate layer 4.

[0045] (2) A phase change energy storage buffer module is set at the node of the sleeve-type heat compensation pipeline module and is filled with phase change material 10. The phase change material 10 is used to compensate the temperature of the sleeve-type heat compensation pipeline module by utilizing the latent heat of phase change.

[0046] (3) Coaxial air curtain antifreeze spray module, which is located at the end of the sleeve-type heat compensation pipeline module, includes a central spray hole connected to the inner pipe 7 and an annular spray hole surrounding the central spray hole; the annular spray hole is used to synchronously spray fluid medium to form a physical isolation layer that wraps around the central CO2 jet.

[0047] (4) Cold energy recovery and intelligent linkage module, including heat exchanger 11 and sensor 12; the heat exchanger 11 is used to recover the cold energy generated by CO2 vaporization and output it to the cooling target area; the sensor 12 is used to monitor the environmental and personnel status, and thereby control the operation status of the sleeve-type heat compensation pipeline module and the coaxial air curtain antifreeze spray module.

[0048] Furthermore, the specific implementation process of the sleeve-type thermal compensation pipeline module is as follows:

[0049] The sheathed thermal compensation piping module constitutes the underlying physical architecture for liquid carbon dioxide transportation and temperature control. In three-dimensional space, this module presents a multi-layered nested coaxial piping structure, consisting of an inner pipe 7, a heat-conducting intermediate layer 4, and an outer pipe 5, arranged sequentially from the inside out. The inner pipe 7 is configured as the main pressure-bearing fluid channel for the directional transportation of cryogenic liquid carbon dioxide. To adapt to the extremely low temperature and high pressure fluid dynamics conditions, the inner pipe 7 is made of a cryogenically resistant seamless stainless steel alloy. The outer pipe 5 surrounds the inner pipe 7, and the difference in their radial dimensions defines the volume of the heat-conducting intermediate layer 4. The inlet end of the outer pipe 5 is connected to the output interface of the mine heat source extraction system. The mine heat source extraction system collects geothermal resources from the mine or extracts waste heat from the operation of air compressor equipment through a pre-set heat exchange network, and transfers this heat energy to the circulating hot fluid via a plate heat exchanger 11. The circulating hot fluid continuously supplied and transported inside the outer pipe 5 is an ethylene glycol antifreeze solution of a specific concentration. Through the closed-loop control logic of the pipeline network, the temperature parameter of the ethylene glycol solution is strictly limited to the range of 15°C to 25°C.

[0050] To ensure the coaxiality of the inner tube 7 and the outer tube 5 and to resist the structural thermal expansion and contraction and radial displacement stress induced by the large temperature difference between the inside and outside of the tubes, a coaxial positioning assembly is installed between the outer wall of the inner tube 7 and the inner wall of the outer tube 5. The coaxial positioning assembly consists of several thermally conductive support rings 3 arranged at equal intervals along the axial extension direction of the inner tube 7. The inner edge of each thermally conductive support ring 3 is tightly welded or press-fitted to the outer wall of the inner tube 7, while its outer edge forms a sliding contact or rigid limit with the inner wall of the outer tube 5. Multiple through holes are opened through the annular body of the thermally conductive support ring 3 along its central axis. This group of through holes is arranged in a uniform array on the solid cross-section of the thermally conductive support ring 3, and its physical function is to open up the annular space interrupted by adjacent thermally conductive support rings 3, so that the interlayer between the inner tube 7 and the outer tube 5 forms a three-dimensional chamber with continuous fluid communication in the axial direction.

[0051] The aforementioned continuous three-dimensional chambers constitute the main space of the thermally conductive intermediate layer 4. This space is completely filled with graphene thermally conductive silicone using a high-pressure injection process. During the manufacturing and assembly stage, liquid graphene thermally conductive silicone base material is pumped in through the pre-set injection port on the outer tube 5. Driven by the pressure difference, the base material smoothly passes through the through holes opened on the surface of each thermally conductive support ring 3, spreading axially and radially until it fills all the mechanical gaps between the inner tube 7 and the outer tube 5. Subsequently, it is transformed into a solid network interlayer with high thermal conductivity through a curing process.

[0052] During the liquid carbon dioxide injection or transportation operation, a dynamic thermodynamic conduction process is triggered within the sheathed thermal compensation pipeline module. The 15°C to 25°C ethylene glycol solution flowing inside the outer tube 5 carries a large amount of sensible heat. This heat is first transferred across the fluid boundary layer to the inner wall of the outer tube 5 via convection heat transfer. The heat absorbed by the inner wall of the outer tube 5 is then converted into solid-state heat conduction, entering the cured graphene thermally conductive silicone and the metal thermally conductive support ring 3. Based on the lattice vibration and electronic heat transfer characteristics of graphene, the heat flow vector is mainly transmitted radially inward at high speed within the thermally conductive intermediate layer 4, eventually reaching and penetrating the outer wall of the inner tube 7. When the transport of low-temperature liquid carbon dioxide inside the inner tube 7 causes a rapid cooling of the tube's metal matrix, the radial heat flow continuously introduced by the thermally conductive intermediate layer 4 forms a reverse thermal compensation flux on the cross-section of the inner tube 7 wall. This physical conduction process enables the heat loss rate and heat replenishment rate of the inner tube 7 wall to reach a dynamic balance, thereby maintaining the temperature of the outer tube 5 wall and the surrounding environment interface above the condensation point without changing the liquid phase state of carbon dioxide inside the tube.

[0053] Furthermore, the specific implementation process of the phase change energy storage buffer module is as follows:

[0054] In the critical node area of ​​the sleeve-type thermal compensation pipeline module, specifically the main pipeline section preceding the pipeline diversion hub and the terminal injection actuator, a phase change energy storage buffer module is physically configured in the system. The external physical boundary of this module is defined by an energy storage shell 9 located on the outermost surface of the pipeline. The energy storage shell 9 is cold-formed from a metal substrate with high structural strength and pressure resistance. Its inner wall is rigidly connected to the outermost pipe wall of the sleeve-type thermal compensation pipeline module through full penetration welding or high-strength flange sealing and anchoring process, thereby constructing a completely closed, pressure-resistant, and independently operating annular energy storage chamber at the structural gap between the two.

[0055] To overcome the inherent physical defect of low thermal conductivity in the pure state of conventional phase change media, a three-dimensional thermally conductive framework 8 is pre-assembled and rigidly fixed in the internal three-dimensional space of the aforementioned independent energy storage chamber. This framework system is not a discrete distribution of debris or unidirectional guide rails, but rather a spatial matrix structure composed of several high-thermal-conductivity fins made of high-thermal-conductivity metal substrates such as copper or high-purity aluminum alloy, combined through positive interlocking and vacuum brazing processes. In terms of mechanical assembly, the root of each set of high-thermal-conductivity fins forms a metallurgically bonded thermal interface with the outer wall of the sleeve-type thermal compensation pipeline module, ensuring that the interface contact thermal resistance is compressed to an extremely low threshold. The extended ends of the high-thermal-conductivity fins extend in multiple directions, penetrating, suspending, and deeply interspersed within the effective volume of the energy storage chamber.

[0056] Within the energy storage chamber and the redundant space completely enclosing the aforementioned three-dimensional heat-conducting framework 8, a working medium, namely phase change material 10, is injected under high pressure. In this embodiment, the phase change material 10 is precisely proportioned and defined as a paraffinic hydrocarbon compound with a specific melting point between 2°C and 8°C, or a specific hydrated salt-based inorganic compound. Under the ambient temperature conditions of conventional mine operations, the phase change material 10 maintains a free-flowing liquid phase physical state and completely immerses and covers all extended end faces of the three-dimensional heat-conducting framework 8.

[0057] When the system switches to liquid carbon dioxide delivery or fire extinguishing spray mode, the high-speed migration of the cryogenic fluid inside the inner pipe 7 triggers a severe temperature drop boundary condition on the pipe wall and even at the local level. At this time, the cold difference attached to the outer wall of the sheathed thermal compensation pipeline module is rapidly introduced to the root of the high thermal conductivity fins through the contact interface with extremely low thermal resistance, and performs a high-speed thermodynamic conduction operation along the spatial matrix structure of the three-dimensional thermally conductive skeleton 8 to the outer depth of the energy storage chamber. As the temperature drop gradient advances along the fin surface to the outer edge, when the local temperature falls below the preset lower limit of the phase change critical temperature, i.e., the lower limit of the range of 2°C to 8°C, the phase change material 10 in the liquid phase triggers nucleation at the solid-liquid interface of the three-dimensional thermally conductive skeleton 8, accompanied by a phenomenal crystallization and solidification phase change process. In the physical process of the transformation from a disordered liquid phase to an ordered solid crystal, the phase change material 10 releases a high density of latent heat of solidification in situ. The latent heat of solidification then causes a reversal in the local heat flux. The released heat energy is captured by the metal lattice of the three-dimensional thermally conductive framework 8 and conducts back at high speed to the outer wall of the sleeve-type heat compensation pipeline module along a physical path that is completely opposite to the initial cold transfer, thereby forming a physical-level heat counteraction and in-situ compensation for the local temperature drop gradient of the pipeline.

[0058] When the liquid carbon dioxide transport operation is stopped, and the ambient temperature around the system or the temperature of the circulating antifreeze in the outer pipe 5 of the sheathed thermal compensation pipeline module rises and establishes a new positive thermodynamic gradient, the phase change material 10, in a solid-state crystalline state, continues to absorb the sensible heat input from the environment through the same heat transfer path. As the crystal structure disintegrates due to heat, the phase change material 10 remelts from the solid phase at the skeleton interface, crosses the phase transition point, and finally completely returns to its initial liquid-phase fluid state. This process, while absorbing excess ambient heat, completes the latent heat storage physical cycle of the phase change material 10 in response to the next cryogenic condition. The reversible phase change operation of the entire phase change energy storage buffer module is entirely dependent on the alternating thermodynamic boundary condition changes derived from the fluid inside the pipe, resulting in a passive response without the need for any external electrical drive components or electronic temperature control intervention.

[0059] Furthermore, the specific implementation process of the coaxial air curtain antifreeze spray module is as follows:

[0060] At the end operating area of ​​the sleeve-type thermal compensation pipeline module, the system is rigidly equipped with a coaxial air curtain antifreeze injection module. This module, as the final fluid dynamics execution terminal, adopts a coaxial nested multi-layered rotating spatial structure. Its core is a central injection pipe 1, whose rear end face is fluidly connected to the inner pipe 7 of the sleeve-type thermal compensation pipeline module via a high-pressure thread or flange assembly to receive the main jet of cryogenic liquid carbon dioxide. A micro-orifice array is formed on the closed end face of the central injection pipe 1. Specifically, this orifice system consists of multiple small-diameter central nozzles arranged according to a matrix or stylized pattern. This physical structure of the orifice array causes the liquid carbon dioxide to encounter a sudden change in cross-section when it breaks through the physical boundary, resulting in a violent phase change and throttling expansion. When carbon dioxide is injected into a closed goaf or fire zone through a borehole or buried pipe, the injection structure can be installed at the inlet end of both the borehole and the buried pipe.

[0061] A peripheral shroud is coaxially fitted around the central jet pipe 1. A constant radial rotational space is reserved between the inner wall of the peripheral shroud and the outer wall of the central jet pipe 1, extending axially to form an annular flow channel. Along the direction of fluid propagation, this annular flow channel undergoes a geometrical change in diameter near the physical position of the orifice array at the front end of the central jet pipe 1. The inner wall of the peripheral shroud exhibits an inwardly contracting nonlinear transition profile, thus defining an annular nozzle with a sharply reduced cross-sectional area with the outer edge of the central jet pipe 1. Based on the fluid dynamics continuity equation, this mechanically contracting cross-section forces a physical conversion from static pressure to dynamic pressure in the fluid medium passing through this point, thereby achieving an extremely high initial jet velocity.

[0062] To impose a defined physical boundary on the central main jet, the jet guide surface of the annular nozzle is machined at a preset angle, so that its jet axis is not parallel to the main jet axis of the central nozzle, but forms a tight forward angle of 5° to 15°. When the pressurized fluid medium is forced to escape at high speed from this annular nozzle with a forward angle, the outer jet trajectory interweaves and converges in three-dimensional space, forming a dynamic conical fluid barrier with a forward converging geometric tendency, which constitutes a mechanical physical isolation of the internal carbon dioxide main jet.

[0063] In terms of fluid delivery path configuration, the cylindrical sidewalls of the outer fairing are machined with radially penetrating fluid inlet ports. The inner end of this fluid inlet port is directly connected to the starting point of the aforementioned annular flow channel, while its outer end is equipped with a high-pressure quick-connect hose connector. This hose connector is configured to physically connect to the pre-laid main line of the mine's compressed air system or dust suppression water supply network. Through this connection interface, the system directly extracts high-pressure ambient temperature air or dust suppression water from the mine's pipeline network as the fluid medium for constructing the aforementioned dynamic conical fluid barrier.

[0064] Furthermore, the specific operation procedure for the cold energy recovery and intelligent linkage module is as follows:

[0065] At the physical junction of the main output pipeline of the liquid carbon dioxide storage tank area and the sheathed heat compensation pipeline module, a cold energy recovery and intelligent linkage module is integrated into the system. The core node of this module at the fluid pipeline network level is a vaporization heat exchanger 11 with an antifreeze and anti-clogging configuration. The main heat exchange side of the vaporization heat exchanger 11 is connected in series in the main liquid carbon dioxide transmission trunk line, and its cold energy output side extends outward through a pressure-resistant insulated circulation pipeline network, and is finally connected to the evaporator end of the independent air conditioning system in the underground electromechanical chamber or the cold source supply station interface of the personnel cooling suit through flanges or standard pipe fittings. When the system is in a non-jet state or a low flow rate maintenance condition, the cold energy generated by the slow phase change vaporization of carbon dioxide accumulated in the pipeline network due to absorption of ambient heat is captured by the vaporization heat exchanger 11 and transported directionally to the above-mentioned terminal heat exchange node via the insulated circulation pipeline network using the refrigerant as a carrier, to perform physical cooling.

[0066] At the hardware topology level for signal sensing and control execution, this module is configured with 12 sets of sensors and a main control unit built based on the intrinsically safe 6 explosion-proof electrical standard for underground coal mines. Specifically, the 12 sets of sensors include an intrinsically safe 6 infrared thermal imaging sensor 12, which is fixed to the outer wall of the sleeve-type thermal compensation pipeline module using a non-destructive patch encapsulation, and an intrinsically safe 6 microwave induction sensor 12, which is deployed in the effective operating space of the coaxial air curtain antifreeze spray module via an explosion-proof bracket. The main control unit is a mine-use explosion-proof programmable logic controller (PLC) with an explosion-proof housing. The intrinsically safe 6 infrared thermal imaging sensor 12 continuously acquires the two-dimensional temperature field distribution simulation signal of the pipeline outer wall, and the intrinsically safe 6 microwave induction sensor 12 continuously monitors the presence of frequency shift characteristic signals representing human displacement in the operating space based on the Doppler effect. The above two underlying physical signals are processed by the high-isolation intrinsically safe 6 safety barrier, converted into standard digital levels, and continuously fed into the input port of the mine-use explosion-proof programmable logic controller.

[0067] The mining explosion-proof programmable logic controller is internally configured with a hierarchical relay logic control loop based on tightly bound hardware input states. This control loop has a multi-dimensional hardware action mapping relationship preset according to priority.

[0068] Under the priority condition of cold energy recovery, when the intrinsically safe type 6 microwave induction sensor 12 continuously outputs a low-level signal representing no personnel displacement in the space, the mine explosion-proof programmable logic controller sends a shutdown command to the drive frequency converter of the antifreeze circulation pump connected to the outer pipe 5, cutting off the active heat source delivery process; simultaneously, it outputs the maximum opening level to the proportional regulating electric valve configured on the cold energy output side of the vaporization heat exchanger 11, forcing the system to enter the state of full power recovery and transfer of cold energy in the pipeline.

[0069] Under personnel protection priority conditions, when the intrinsically safe Type 6 microwave induction sensor 12 detects frequency shift characteristics and flips to output a high-level personnel approach signal, and the local area temperature extreme value returned by the intrinsically safe Type 6 infrared thermal imaging sensor 12 is lower than the system's preset frostbite prevention safety hard threshold parameter, the mine explosion-proof programmable logic controller triggers an internal high-priority interrupt. The controller drive output immediately sends a pull-in pulse to the AC contactor of the antifreeze circulation pump, forcing the pump to start and pumping circulating antifreeze at 15°C to 25°C into the outer pipe 5 space to perform active thermal compensation; simultaneously, it finely adjusts the opening of the electric valve on the cold output side to limit excessive transfer of ambient cold.

[0070] Under forced isolation conditions, once the system bus receives the highest priority operation signal triggered by the closure of the fire extinguishing contact, the mine explosion-proof programmable logic controller will shield all underlying temperature status assessments and directly send a constant excitation current to the intrinsically safe Type 6 solenoid main valve connected in series at the fluid inlet interface. This action ensures that the high-pressure gas or water source completes pipeline pressurization and jet establishment in advance or simultaneously before the central liquid carbon dioxide valve reaches full physical opening. This ensures that within the extremely short time window of disaster emergency response, the outer conical physical isolation layer will inevitably be generated synchronously with the main carbon dioxide jet and maintain a stable structure.

[0071] To ensure the physical opening sequence of the multiphase jet at the timing control level, the rear operating handle area of ​​the coaxial air curtain antifreeze jet module integrates a purely mechanical dual-action linkage valve 2 system. This valve system is driven by an operating handle with a continuous linear displacement stroke. The valve contains two sets of parallel valve core slider mechanisms with a physical difference in trigger thresholds. When the operating handle is initially displaced by force, its mechanical cam mechanism preferentially pushes the first valve core controlling the fluid inlet, causing rapid pressurization of the annular flow channel within the outer shroud, pre-activating a closed physical isolation layer at the working front end. As the handle's downward stroke extends further and breaks through the preset dead zone, the mechanical transmission rod overcomes the internally set spring resistance, thereby actuating the second valve core connected to the central jet pipe 1. Under this forced intervention of the purely mechanical stroke timing, the internal fluid pipeline is opened, allowing liquid carbon dioxide to overcome the valve seat flow resistance and enter the central jet pipe 1 for operation. This action logic, based on the mechanical stroke difference, irreversibly binds the triggering sequence of the two fluids at a physical level.

[0072] 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 the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions will not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A mine-use liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function, characterized in that, include: (1) A sleeve-type thermal compensation pipeline module includes an inner pipe (7), an outer pipe (5) and a thermally conductive intermediate layer (4) located between the two; the inner pipe (7) is used to transport liquid CO2, the outer pipe (5) is used to transport circulating hot fluid, and the heat of the circulating hot fluid is conducted to the inner pipe (7) through the thermally conductive intermediate layer (4). (2) A phase change energy storage buffer module is set at the node of the sleeve-type heat compensation pipeline module and is filled with phase change material (10). The phase change material (10) is used to compensate the temperature of the sleeve-type heat compensation pipeline module by utilizing the latent heat of phase change. (3) Coaxial air curtain antifreeze spray module, which is set at the end of the sleeve-type heat compensation pipeline module, includes a central spray hole connected to the inner pipe (7) and an annular spray hole surrounding the central spray hole; the annular spray hole is used to synchronously spray fluid medium to form a physical isolation layer that wraps around the central CO2 jet. (4) Cold energy recovery and intelligent linkage module, including heat exchanger (11) and sensor (12) group; the heat exchanger (11) is used to recover the cold energy generated by CO2 vaporization and output it to the cooling target area; the sensor (12) group is used to monitor the environmental and personnel status, and thereby control the operation status of the sleeve-type heat compensation pipeline module and the coaxial air curtain antifreeze spray module.

2. The intelligent antifreeze protection system for mine liquid CO2 fire prevention and extinguishing with gas-liquid phase change heat compensation function according to claim 1, characterized in that, The medium filled in the thermally conductive intermediate layer (4) is graphene thermally conductive silicone. The circulating hot fluid transported in the outer pipe (5) is antifreeze, and the antifreeze is an ethylene glycol solution with a temperature maintained at 15℃-25℃.

3. The intelligent antifreeze protection system for mine liquid CO2 fire prevention and extinguishing with gas-liquid phase change heat compensation function according to claim 2, characterized in that, The inlet end of the outer pipe (5) is connected to the mine heat source extraction system, which is used to collect the mine geothermal energy or the waste heat of the air compressor and exchange the heat of the mine geothermal energy or the waste heat of the air compressor into the circulating heat fluid. A coaxial positioning assembly is provided between the outer wall of the inner tube (7) and the inner wall of the outer tube (5); the coaxial positioning assembly includes a plurality of thermally conductive support rings (3) spaced apart along the axial direction of the inner tube (7), and the thermally conductive support rings (3) are provided with through holes for the thermally conductive intermediate layer (4) medium to pass through and fill.

4. The intelligent antifreeze protection system for mine liquid CO2 fire prevention and extinguishing with gas-liquid phase change heat compensation function according to claim 3, characterized in that, The phase change energy storage buffer module includes an energy storage shell (9) sleeved outside the key node of the sleeve-type thermal compensation pipeline module. The energy storage shell (9) and the outermost pipe wall of the sleeve-type thermal compensation pipeline module form a closed energy storage chamber. The phase change material (10) is filled in the energy storage chamber. The key node includes the pipeline branch and the front side of the injection operation end. The energy storage chamber is also provided with a three-dimensional thermally conductive skeleton (8), which is composed of several high thermal conductivity fins connected in an alternating manner; the root of the high thermal conductivity fins is thermally connected to the outer wall of the sleeve-type thermal compensation pipeline module, and the extended end of the high thermal conductivity fins is inserted and immersed in the phase change material (10).

5. A mine-use liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function according to claim 4, characterized in that, The phase change material (10) is a paraffin or brine compound with a specific melting point and a phase change temperature between 2°C and 8°C. The phase change material (10) is configured for reversible phase change operation: when liquid CO2 is transported inside the sleeve-type heat compensation pipeline module, causing the surrounding temperature to drop, the phase change material (10) solidifies from liquid to solid to release the latent heat of solidification; when the system stops spraying and the ambient temperature rises, the phase change material (10) absorbs ambient heat and melts from solid to liquid to store heat.

6. A mine-use liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function as described in claim 5, characterized in that, The coaxial air curtain antifreeze spray module includes a central spray pipe (1) and an outer shroud arranged in a coaxial nested configuration; the front end of the central spray pipe (1) is provided with a plurality of central spray holes arranged in a matrix or plum blossom pattern; an annular flow channel is formed between the outer wall of the central spray pipe (1) and the inner wall of the outer shroud, and the front end of the annular flow channel contracts to form the annular spray holes. The jet axis of the annular nozzle forms a forward angle of 5° to 15° with the main jet axis of the central nozzle, so that the fluid medium ejected from the annular nozzle can form a conical physical isolation layer with a forward converging tendency around the central CO2 jet.

7. A mine-use liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function according to claim 6, characterized in that, The side wall of the outer rectifier is provided with a fluid inlet interface, which is connected to the annular flow channel; the fluid inlet interface is connected to the existing compressed air system pipeline or dustproof water supply pipeline in the mine through a quick-connect hose to obtain normal temperature high pressure air or dustproof water as the fluid medium. A double-acting linkage valve (2) is provided at the rear handle of the coaxial air curtain antifreeze spray module; the double-acting linkage valve (2) is configured as a purely mechanical linkage structure: when the operating handle is pressed, the fluid inlet interface is first opened to open the outer physical isolation layer, and then the inner tube (7) is opened to spray liquid CO2 due to the continued downward pressure of the handle stroke.

8. A mine-use liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function according to claim 7, characterized in that, The heat exchanger (11) is a vaporization heat exchanger (11), which is located at the junction of the main output line of the liquid CO2 storage tank area and the shell-and-tube heat compensation pipeline module. The cold output side of the vaporization heat exchanger (11) is connected to the air conditioning system of the underground electromechanical chamber or the cold source supply station of the personnel cooling suit through an insulated circulation pipeline, which is used to convert the waste cold generated during the vaporization of CO2 into an environmental cooling source.

9. A mine-use liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function according to claim 8, characterized in that, The sensor (12) group includes an intrinsically safe (6) type infrared thermal imaging sensor (12) attached to the outer wall of the sleeve-type thermal compensation pipeline module, and an intrinsically safe (6) type microwave induction sensor (12) deployed in the operating area of ​​the coaxial air curtain antifreeze spray module. The cold energy recovery and intelligent linkage module also includes a mine explosion-proof programmable logic controller that is connected to the signal of the sensor (12) group.

10. A mine-use liquid CO2 fire extinguishing and antifreeze protection system with gas-liquid phase change heat compensation function according to claim 9, characterized in that, The mining explosion-proof programmable logic controller has a built-in hierarchical linkage control module based on hardware status, including: Cold energy recovery priority mode: When the intrinsically safe (6) type microwave induction sensor (12) does not detect the approach of personnel, the circulating hot fluid of the outer tube (5) is controlled to stop being transported, and the cold energy collection circuit of the heat exchanger (11) is maximized. Personnel protection priority mode: When the intrinsically safe (6) type microwave induction sensor (12) detects personnel approaching, and the intrinsically safe (6) type infrared thermal imaging sensor (12) detects that the temperature of the outer wall of the pipeline is lower than the preset antifreeze threshold, the antifreeze circulation pump connected to the outer pipe (5) is automatically started for active heating; Forced isolation mode: When the system receives a fire extinguishing spray trigger signal, it forcibly opens the fluid spray valve of the coaxial air curtain antifreeze spray module, so that the physical isolation layer is generated synchronously with the central CO2 jet.

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