Telescopic phase change rock breaking device

Abstract

The invention discloses a telescopic phase change rock breaking device which comprises a telescopic flexible shell, a telescopic flexible transmission pipe, combustible materials, a liquid filling pipe, an exhaust pipe and an ignition element. The telescopic flexible transmission pipe is inserted into the telescopic flexible shell and connected with the liquid filling pipe; the top of the telescopic flexible shell is provided with a feeding port and an exhaust pipe, the telescopic flexible shell is filled with combustible materials, and the ignition element is located in the combustible materials. The telescopic flexible transmission pipe comprises a first fixed pipe, a second fixed pipe and a telescopic pipe, the first fixed pipe and the second fixed pipe are fixed on the telescopic flexible shell, and the telescopic pipe is connected with the first fixed pipe and the second fixed pipe. According to the telescopic phase change rock breaking device, liquid gas is injected into the rock breaking device from the special Dewar tank through the liquid filling pipe and then is rapidly absorbed by combustible materials, the pressure inside and outside the energy storage cylinder is kept balanced through the exhaust pipe in the liquid filling process, and the shell is prevented from bursting.

Description

Technical Field

[0001] This invention relates to a retractable phase change rock-breaking device, belonging to the field of rock breaking. Background Technology

[0002] In engineering fields such as mining, tunneling, and municipal demolition, rock breaking is one of the core processes, and its efficiency, safety, and environmental friendliness directly determine the project cycle, cost, and ecological impact. While explosive blasting is highly efficient in traditional rock breaking technologies, it carries risks such as strong blast waves, the generation of flyrock and toxic residues, and the need for specialized qualification management. Mechanical crushing (such as hydraulic hammers) suffers from low efficiency and severe equipment wear in hard rock conditions. Against this backdrop, liquid oxygen / liquid nitrogen phase change rock breaking technology, with its core advantages of "low-temperature phase change expansion for work, no chemical pollution, and natural volatile residues," has become a significant area of ​​innovation in the field of rock breaking technology.

[0003] The core principle of this technology is to combine a liquid oxygen / liquid nitrogen mixture with a combustible material through a specific device, and then ignite the combustible material with an ignition element. The released heat causes the liquid gas to undergo an instantaneous phase change (its volume can expand hundreds of times), generating a high-pressure dynamic load that acts on the borehole wall, forming a rock stress wave to achieve rock breaking. However, existing liquid oxygen / liquid nitrogen phase change rock breaking devices have many technical defects in structural design and functional adaptability, which seriously restricts their engineering application effects. Most existing phase change rock breaking devices use rigid shells (such as metal cylinders) or simple flexible shells (without telescopic adjustment structures). Rigid shells cannot adapt to the differences in borehole diameters in different engineering scenarios (such as 60-120mm boreholes commonly used in mining and 150-200mm boreholes in tunnel construction), requiring customized shells of different specifications, increasing construction costs and material preparation time. Although simple flexible shells can deform slightly, the telescopic range is less than 10%, and when facing irregular boreholes, "local poor fit" is likely to occur, leading to leakage of the high-pressure gas generated by the phase change, and a rock breaking pressure loss of more than 30%. Rigid shells require precise matching to the borehole depth, and are prone to collision with the borehole wall during insertion, causing deformation and damaging the liquid gas seal. Simple flexible shells lack a fixed structure, and are prone to sagging due to their own weight after filling, causing wrinkles in the shell, further increasing the risk of seal failure. In extreme cases, it may cause the shell to burst during filling. Summary of the Invention

[0004] Purpose of the invention: In order to overcome the shortcomings of the existing technology, the present invention provides a retractable phase change rock breaking device. Liquid gas is injected into the rock breaking device from a special Dewar canister through a filling pipe and is quickly absorbed by the combustible material. During the filling process, the pressure inside and outside the energy storage cylinder is kept balanced through the exhaust pipe to prevent the outer shell from bursting.

[0005] Technical Solution: To solve the above-mentioned technical problems, the present invention provides a retractable phase change rock-breaking device, comprising a retractable flexible outer shell, a retractable flexible transmission pipe, combustible material, a filling pipe, an exhaust pipe, and an ignition element. The retractable flexible transmission pipe is inserted into the retractable flexible outer shell and is connected to the filling pipe. The top of the retractable flexible outer shell is provided with a feeding port and an exhaust pipe. The retractable flexible outer shell is filled with combustible material, and the ignition element is located in the combustible material. The retractable flexible outer shell is a multi-layer composite retractable pleated structure, comprising a base layer, a reinforcing layer, and a protective layer. The base layer uses low-temperature resistant flexible rubber as the inner substrate, the reinforcing layer is a high-toughness fiber woven mesh, and a high-toughness fiber woven mesh is laminated on the outside of the base layer. The protective layer is a polytetrafluoroethylene coating, with an additional polytetrafluoroethylene coating on the outside of the high-toughness fiber woven mesh. The stretchable flexible transmission tube includes a first fixed tube, a second fixed tube, and a telescopic tube. The first fixed tube and the second fixed tube are fixed to the stretchable flexible outer shell, and the telescopic tube is connected to the first fixed tube and the second fixed tube. Each of the telescopic tube, the first fixed tube, and the second fixed tube is provided with a leakage hole.

[0006] Preferably, both the first and second fixed pipes are provided with branch pipes, with the end of the branch pipe away from the retractable flexible transmission pipe extending to the edge of the combustible material.

[0007] Preferably, guide vanes are installed inside the first and second fixed tubes. The guide vanes are two inclined baffles that are inclined downward in opposite directions and are arranged alternately on the inner wall of the first or second fixed tube.

[0008] Preferably, the tilt angle of the baffle is 30°~60°.

[0009] Preferably, the ignition element includes a housing, a carbon powder inside the housing, an ignition bridge wire inside the carbon powder, a pre-combustion reinforcement layer sprayed on the surface of the ignition bridge wire, the pre-combustion reinforcement layer comprising potassium perchlorate and phenolic resin, the mass ratio of potassium perchlorate to phenolic resin being 9:1, and the ignition bridge wire being led out of the housing through an ignition lead wire.

[0010] Preferably, the outer casing is provided with a number of through holes.

[0011] Preferably, the toner has at least three conical vent holes, with the upper end of the conical vent hole having a smaller diameter and the lower end having a larger diameter.

[0012] Preferably, the diameter of the lower end of the conical vent is 1.5 times the diameter of the upper end.

[0013] Preferably, the toner is compacted toner with a density of 0.85-0.90 g / cm³.

[0014] The retractable flexible shell features a multi-layered composite retractable pleated structure, specifically including: ① Base layer: Low-temperature resistant flexible rubber (such as nitrile rubber) is used as the inner base material, possessing a low-temperature tolerance of -196℃ to prevent liquid gas leakage. It also has basic elasticity and stretching capacity, with a stretching rate of 20%-30%, adaptable to boreholes of different diameters. ② Reinforcing layer: A high-toughness fiber woven mesh (such as Kevlar fiber mesh) is laminated to the outside of the inner rubber layer. The fiber mesh is woven in a ring-like interlaced pattern, forming a retractable pleated skeleton. This enhances the shell's resistance to burst pressure and allows for flexible adjustment of the shell diameter through the expansion and contraction of the pleats, adapting to boreholes of different specifications from 60-200mm. It can also conform to irregular borehole walls to prevent gas leakage. ③ Protective layer: A wear-resistant polytetrafluoroethylene coating is added to the outside of the fiber mesh to reduce frictional wear between the shell and the borehole wall when inserted, improving the reusability of the device and the structural stability during construction.

[0015] Beneficial effects: The expandable phase change rock-breaking device of this invention features a flexible shell whose expansion and contraction characteristics can adaptively adjust to the diameter and shape of the borehole. This eliminates the need for customized shells for different engineering scenarios, avoiding the problems of "fixed size and narrow adaptability" of traditional rigid or simple flexible shells, and enabling the universal application of the same device in various rock-breaking scenarios. The flexible material avoids the risk of deformation due to collision with the borehole wall when the rigid shell is inserted. Simultaneously, the expandable structure can adapt to irregular borehole shapes, reducing shell wrinkles or damage, and mitigating safety hazards such as liquid gas leakage and shell bursting during installation. The dense structure of the compacted carbon powder avoids the clumping and moisture absorption problems of traditional loose powder in low-temperature environments such as liquid oxygen / liquid nitrogen. Combined with the chemical energy assistance of the pre-combustion reinforcement layer, it ensures that the ignition element maintains its ignition activity at extreme low temperatures, solving the fundamental defect of "low-temperature misfires." The heat and gas released by the pre-combustion enhancement layer can form a directional impact through the conical vent holes, quickly igniting the surrounding combustibles. This avoids the problems of "rapid heat loss and non-concentrated ignition core" in traditional ignition structures, ensuring that the ignition energy is accurately applied to the "key trigger point" of the liquid-gas phase change, and improving the phase change response speed. Attached Figure Description

[0016] Figure 1 This is a schematic diagram of the structure of the present invention.

[0017] Figure 2 This is a schematic diagram of the ignition element.

[0018] Figure 3 This is a schematic diagram of the cross-sectional structure of the ignition element.

[0019] In the diagram: 1. Ignition element; 2. Branch pipe; 3. Combustible material; 4. Stretchable flexible transmission pipe; 5. Stretchable flexible outer shell; 6. Liquid filling pipe; 7. Second fixed pipe; 8. Guide plate structure; 9. Conical vent hole. Detailed Implementation

[0020] The invention will now be further described with reference to the accompanying drawings.

[0021] like Figures 1 to 3 As shown, the retractable phase change rock-breaking device of the present invention includes a retractable flexible shell, a retractable flexible transmission pipe, combustible material, a filling pipe, an exhaust pipe, and an ignition element. The retractable flexible transmission pipe is inserted into the retractable flexible shell and is connected to the filling pipe. The top of the retractable flexible shell is provided with a feeding port and an exhaust pipe. The retractable flexible shell is filled with combustible material, and the ignition element is located in the combustible material. The retractable flexible transmission pipe includes a first fixed pipe, a second fixed pipe, and a telescopic pipe. The first fixed pipe and the second fixed pipe are fixed to the retractable flexible shell, and the telescopic pipe is connected to the first fixed pipe and the second fixed pipe. Each of the telescopic pipe, the first fixed pipe, and the second fixed pipe is provided with a leakage hole. The retractable flexible shell is a multi-layer composite retractable pleated structure, specifically including: ① Base layer: using low-temperature resistant flexible rubber (such as nitrile rubber) as the inner base material, which has a low temperature resistance of -196℃, can prevent liquid gas leakage, and has basic elastic expansion and contraction capacity, with an expansion rate of 20%-30%, adaptable to different diameter boreholes. ② Reinforcing Layer: A high-toughness fiber woven mesh (such as Kevlar fiber mesh) is laminated to the outside of the inner rubber layer. The fiber mesh is woven in a ring-shaped interlaced pattern, forming a stretchable pleated skeleton. This not only enhances the outer shell's resistance to burst pressure but also allows for flexible adjustment of the outer shell's diameter through the unfolding and contraction of the pleats, adapting to different specifications of boreholes from 60-200mm. It can also conform to irregular borehole walls to prevent gas leakage. ③ Protective Layer: A wear-resistant polytetrafluoroethylene coating is added to the outside of the fiber mesh to reduce frictional wear between the outer shell and the borehole wall when inserted into the borehole, improving the reusability of the device and the structural stability during construction.

[0022] In this invention, the retractable flexible shell and basic accessories are as follows: The main structure is made of a flexible material with retractable properties, and the shell can adaptively adjust its shape according to the external space size; The top accessories are: a feeding port and an exhaust pipe are opened on the top of the shell. The feeding port is used to fill the shell with combustibles, and the exhaust pipe is used to balance the pressure inside and outside the shell during the filling process to avoid sudden pressure rise that could cause the shell to break.

[0023] In this invention, the retractable flexible transmission tube system comprises the following main components: a first fixed tube, a second fixed tube, and a telescopic tube. The first and second fixed tubes are respectively fixed at designated positions on the inner wall of the retractable flexible shell (ensuring positional stability). The two ends of the telescopic tube are connected to the first and second fixed tubes respectively, forming a complete liquid-gas transmission channel. A leakage structure is provided: leakage holes are provided in the bodies of the telescopic tube, the first fixed tube, and the second fixed tube, allowing liquid gas to seep out into the surrounding combustible material. Branch pipe extension: branch pipes are connected to the side walls of both the first and second fixed tubes. The end of the branch pipe away from the transmission tube extends towards the edge of the combustible material until it reaches the vicinity of the inner wall of the shell, ensuring that the liquid gas can be delivered to the edge area of ​​the combustible material.

[0024] In this invention, the flow guide structure has flow guides installed inside both the first and second fixed tubes. The flow guides consist of two inclined baffles: Inclination direction: the two baffles are inclined downwards in opposite directions, that is, one baffle is inclined downwards to the left side of the tube and the other is inclined downwards to the right side of the tube; Arrangement: the two baffles are arranged alternately on the inner wall of the fixed tube, forming an alternating "left-inclined-right-inclined" structure to ensure that the liquid gas flowing through the fixed tube can fully contact the baffles.

[0025] In this invention, the ignition element comprises a shell and internal filling: the ignition element includes an independent shell with several through holes; compacted carbon powder is filled into the shell to ensure a dense state; ignition assembly: an ignition bridge wire is embedded inside the compacted carbon powder, and a pre-combustion reinforcement layer (made from a mixture of potassium perchlorate and phenolic resin in a 9:1 mass ratio) is sprayed onto the surface of the ignition bridge wire; ignition leads are connected to both ends of the ignition bridge wire, one end of which is fixed to the bridge wire, and the other end passes through the shell of the ignition element for subsequent connection to an external excitation device; venting structure: at least three conical venting holes are formed on the compacted carbon powder, the upper diameter of the conical venting hole is smaller than the lower diameter, and the lower diameter is 1.5 times the upper diameter, with the venting holes extending from the top of the carbon powder to near the bottom of the shell.

[0026] Assembly process of the device of the present invention:

[0027] Pre-assembly of transmission pipe and guide vanes: First, install the guide vanes inside the first fixed pipe and the second fixed pipe, ensuring that the baffles are staggered and tilted in the correct direction; then connect the branch pipe to the fixed pipe, then fix the first fixed pipe and the second fixed pipe to the inner wall of the telescopic flexible shell, and finally connect the telescopic pipe between the two fixed pipes to complete the assembly of the transmission pipe system;

[0028] Combustible material filling: Through the feeding port at the top of the shell, slowly fill the retractable flexible shell with combustible material. During the filling process, gently tap the shell to ensure that the combustible material is evenly distributed and without obvious gaps, until it is filled to near the top of the shell (leaving space for the installation of ignition elements).

[0029] Ignition element installation: Place the prefabricated ignition element into the central area inside the combustible material, ensuring that the through hole on the ignition element housing can fully contact the surrounding combustible material, and at the same time pass the ignition lead out through the gap at the top of the housing to facilitate subsequent connection to the ignition device.

[0030] Attachment inspection: Confirm that the exhaust pipe is unobstructed and unblocked, the feeding port is sealed (close and seal after filling), the transmission pipe and branch pipe are not loose, the overall device structure is stable, and the assembly is complete.

[0031] The working process of the device of the present invention:

[0032] Liquid gas filling: Connect the liquid inlet of the external Dewar canister to the retractable flexible transmission tube. Liquid gas enters the device through the transmission tube. When flowing through the first fixed tube, the retractable tube, and the second fixed tube, part of it seeps out through the leakage hole in the tube body, and part of it is transported to the edge of the combustible material through the branch tube. When flowing through the fixed tube, the flow direction is changed by the inclined baffle, forming turbulence and promoting the full mixing of liquid gas and combustible material. During the filling process, the air inside the outer shell is discharged through the exhaust pipe to maintain pressure balance.

[0033] Ignition and activation: Connect the ignition lead to the external activation device. After the activation device is started, the ignition bridge wire is energized and heated. The surface pre-combustion reinforcement layer reacts quickly and releases heat and gas, igniting the internal compacted carbon powder. The high temperature and high pressure gas generated by the carbon powder combustion impacts the surrounding combustibles through the conical vent holes, causing the combustibles to burn violently.

[0034] Phase change rock breaking: The heat released by the combustion of combustibles causes the liquid gas to undergo an instantaneous phase change, and the volume expands rapidly to generate a high-pressure load. The stretchable and flexible shell expands outward under the pressure, adheres tightly to the borehole wall, and transmits the high-pressure load to the borehole wall, forming a rock stress wave, which ultimately achieves rock breaking.

[0035] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A retractable phase change rock-breaking device, characterized in that: The device includes a retractable flexible outer shell, a retractable flexible transmission tube, a combustible material, a filling tube, an exhaust tube, and an ignition element. The retractable flexible transmission tube is inserted into the retractable flexible outer shell and is connected to the filling tube. The top of the retractable flexible outer shell has a feeding port and an exhaust tube. The retractable flexible outer shell is filled with combustible material, and the ignition element is located in the combustible material. The retractable flexible outer shell is a multi-layer composite retractable pleated structure, including a base layer, a reinforcement layer, and a protective layer. The base layer uses low-temperature resistant flexible rubber as the inner substrate. The reinforcement layer is a high-toughness fiber woven mesh, and a high-toughness fiber woven mesh is laminated to the outside of the base layer. The protective layer is a polytetrafluoroethylene (PTFE) coating, and a PTFE coating is added to the outside of the high-toughness fiber woven mesh. The retractable flexible transmission tube includes a first fixed tube, a second fixed tube, and a telescopic tube. The first fixed tube and the second fixed tube are fixed to the retractable flexible outer shell, and the telescopic tube is connected to the first fixed tube and the second fixed tube. Each of the telescopic tube, the first fixed tube, and the second fixed tube has a leakage hole.

2. The expandable phase change rock-breaking device according to claim 1, characterized in that: Both the first and second fixed pipes are provided with branch pipes, with the end of the branch pipe away from the retractable flexible transmission pipe extending to the edge of the combustible material.

3. The expandable phase change rock-breaking device according to claim 2, characterized in that: The first and second fixed tubes are equipped with guide vanes, which are two inclined baffles that are inclined downward in opposite directions and are arranged alternately on the inner wall of the first or second fixed tube.

4. The expandable phase change rock-breaking device according to claim 3, characterized in that: The tilt angle of the baffle is 30°~60°.

5. The expandable phase change rock-breaking device according to claim 1, characterized in that: The ignition element includes a housing, a carbon powder inside the housing, an ignition bridge wire inside the carbon powder, a pre-combustion reinforcement layer sprayed on the surface of the ignition bridge wire, the pre-combustion reinforcement layer comprising potassium perchlorate and phenolic resin, the mass ratio of potassium perchlorate to phenolic resin being 9:1, and the ignition bridge wire being led out of the housing through an ignition lead wire.

6. The extendable phase change rock-breaking device according to claim 5, characterized in that: The outer shell has several through holes.

7. The expandable phase change rock-breaking device according to claim 5, characterized in that: The toner has at least three conical vent holes, with the upper end of the conical vent hole having a smaller diameter and the lower end having a larger diameter.

8. The extendable phase change rock-breaking device according to claim 7, characterized in that: The diameter of the lower end of the conical vent is 1.5 times that of the upper end.

9. The expandable phase change rock-breaking device according to claim 1, characterized in that: The toner is compacted toner with a density of 0.85-0.90 g / cm³.

Images