Controllable strong static fracturing rod

Abstract

The utility model discloses a controllable strong static fracturing rod which comprises a plurality of sections of charging barrels which are sequentially connected end to end in the vertical direction, a water passing pipe is coaxially arranged in the charging barrels, and a plurality of small water-permeable holes communicated with the interiors of the charging barrels are formed in the water passing pipe. The upper end and the lower end of the water pipe are both provided with connecting pieces used for pressing all the series-connection powder charging barrels, and a guide head is arranged at the upper end of the water pipe. According to the utility model, the outer cylinder body, the inner cylinder body, the upper constraint end cover and the lower constraint end cover are manufactured and installed by adopting a split structure, so that the diameter of the outer cylinder body and the diameter of the inner cylinder body can be conveniently adjusted according to the hole diameter of a drilled hole, and the problem that holes are easily sprayed when the device is used for large-hole-diameter drilling (more than phi 50mm) is solved; the advantages of no vibration, no open fire, no harmful gas and the like of the static fracturing technology are kept, the fracturing capacity is improved, and the application scene of the static fracturing technology is expanded.

Description

Technical Field

[0001] The utility model belongs to the technical field of coal mine production safety, and particularly relates to a controllable strong static fracturing rod. Background Art

[0002] Static fracturing technology is currently being increasingly used in coal rock fracturing in coal mines, especially in the fracturing of hard coal roofs. Due to the advantages of no vibration, no harmful gases, and no noise during the use of static fracturing technology, it is safer and more convenient to use than traditional blasting solutions and is more suitable for the underground coal mine environment.

[0003] Static fracturing agents are mainly made of CaO. After reacting with a certain proportion of water, they slowly expand and release a certain amount of heat. When implementing specific on-site projects, it is necessary to construct drilling holes in advance, and then the stirring grouting method can be used. The fracturing agent can be made into a fracturing rod type, which can be loaded into the borehole to expand and fracture. Chinese patent applications CN202411186322.X and CN202411186325.3 disclose expansion fracturing rod devices that can be retained in the borehole. The use of static fracturing technology is more suitable for the engineering conditions of coal mine roof fracturing, and has achieved better economic benefits and on-site value.

[0004] However, the strength of coal seam roofs varies across mining areas. For particularly hard roofs, a static fracturing agent with a greater expansion force is required. This expansion force can be increased by increasing the borehole diameter. Experimental studies have shown that doubling the diameter and increasing the amount of expansion agent loaded into the borehole by fourfold can increase the expansion force by two to four times. However, increasing the amount of fracturing agent also increases the heat of reaction, increasing the probability of blowout. Field tests have shown that the probability of blowout increases significantly when the borehole diameter exceeds 50mm, posing a safety risk and compromising the fracturing effect.

[0005] Chinese patent applications CN202411186322.X and CN202411186325.3 disclose expansion fracturing rod devices that can be retained in a borehole. However, these devices have the following drawbacks in practical applications:

[0006] (1) There is a very small gap (clearance fit) between the outer circle of the water pipe and the inner circle of the inner cylinder. When the static fracturing agent expands, there is no inward expansion space. For a particularly hard top plate, this will cause the static fracturing agent to spray out.

[0007] (2) The outer cylinder and the inner cylinder of the cartridge are connected as a whole through a fixed constrained end cap at one end, and a movable constrained end cap is set at the other end for sealing after the static fracturing agent is loaded. This structure is not convenient for replacing outer cylinders and inner cylinders with different outer diameters, the loading amount is uncontrollable, and it is difficult to adapt to different hole diameters, especially large hole diameters (drilling diameter>50mm). Utility Model Content

[0008] In order to solve the above technical problems, the utility model provides a controllable strong static fracturing rod which can be assembled in full detachable form, has an outer cylinder and an inner cylinder which can be easily replaced according to different drilling holes and top plate strengths, and is not prone to spray holes.

[0009] To solve the above technical problems, the utility model adopts the following technical solutions: a controllable strong static fracturing rod, comprising a plurality of cartridges connected in sequence vertically end to end, a water pipe coaxially arranged inside the cartridge, a plurality of water-permeable holes opened on the water pipe, all of which are connected to the interior of the cartridge, a connector for pressing all the cartridges in series at both the upper and lower ends of the water pipe, and a guide head provided at the upper end of the water pipe;

[0010] The drug-loading cartridge includes an outer cylinder body, an inner cylinder body, an upper constraint end cover and a lower constraint end cover which are coaxially arranged. The upper constraint end cover and the lower constraint end cover have the same structure and are symmetrically arranged up and down. A circular hole for passing a water pipe is provided in the center of the upper constraint end cover and the lower constraint end cover. The diameter of the circular hole is equal to the outer diameter of the water pipe. The inner diameter of the inner cylinder is larger than the diameter of the circular hole. A water-permeable seam is provided on the inner cylinder body. An annular groove is provided on the bottom surface of the upper constraint end cover and the top surface of the lower constraint end cover. An annular step is provided on the outer edge of the bottom surface of the upper constraint end cover and the top surface of the lower constraint end cover. The upper and lower ends of the inner cylinder body are respectively assembled and inserted into the annular groove of the upper constraint end cover and the annular groove of the lower constraint end cover. The upper and lower ends of the outer cylinder body are respectively assembled onto the annular steps of the upper constraint end cover and the annular steps of the lower constraint end cover; the annular cavity formed between the inner circle of the outer cylinder and the outer circle of the inner cylinder is filled with static fracturing powder.

[0011] The outer circle of the upper end of the guide head is a conical surface that is thinner at the top and thicker at the bottom. A mounting hole for passing a water pipe is opened in the center of the guide head.

[0012] The water pipe is made of threaded steel pipe, and the connecting parts include fastening nuts and pads. The pads are sleeved on the water pipe, and the fastening nuts are threadedly connected to the water pipe.

[0013] The fastening nut of the connector at the lower end presses the backing plate tightly against the bottom surface of the lower restraint end cover at the lowest end;

[0014] The guide head is provided between the pad of the upper connecting piece and the fastening nut, and the fastening nut presses the pad to the top surface of the upper constraint end cover through the guide head.

[0015] A full-length sealing rubber sleeve is provided on the outside of the guide head and all the segmented cartridges. The upper end of the sealing rubber sleeve is wrapped around the conical surface at the upper end of the guide head after heat shrinkage.

[0016] Two anti-slip steel plates are fixed on the outer circle of the guide head. The two anti-slip steel plates are symmetrically arranged about the center line of the guide head. Both anti-slip steel plates extend out of the sealing rubber sleeve. The upper end of the anti-slip steel plate is fixedly connected to the outer circle of the guide head. The angle between the length direction of the anti-slip steel plate and the center line of the guide head is an acute angle.

[0017] By adopting the above technical solution, the present invention has significant improvements as follows:

[0018] (1) When in use, it is only necessary to connect multiple static fracturing rods to the water pipe ports through the connecting straight-through connection and then install them into the borehole. When the borehole opening is sealed, a water injection pipe must be reserved. The upper end of the water injection pipe is connected to the lower end of the water pipe in the lowest static fracturing rod. When reaction fracturing is required, water can be injected into the borehole through the water injection pipe. When the static fracturing rod is installed in the borehole, the two anti-skid steel plates are compressed under their own elasticity and move upward along the borehole. After the fracturing rod is installed in place, the anti-skid steel plates are unfolded and the lower end of the anti-skid steel plates penetrate into the inner wall of the borehole, which can ensure that the static fracturing rod will not slide down.

[0019] (2) The static fracturing agent is placed in the annular cavity formed between the outer and inner cylinders. The diameters of the outer and inner cylinders can be adjusted proportionally. The inner diameter of the inner cylinder is larger than the diameter of the water pipe. The inner cylinder is filled with clean water, which has a larger clean water storage capacity, ensuring that the static fracturing agent can absorb water and react. At the same time, the pre-stored clean water can also absorb more heat. On the basis of ensuring the fracturing effect under large-diameter drilling conditions, the fracturing agent spray hole is avoided.

[0020] (3) The static fracturing powder is compacted to a certain density and loaded into the cartridge. During the storage and transportation of the fracturing rod, sealing caps are respectively set at the two ends of the water pipe. This makes the entire static fracturing rod a fully enclosed packaging structure. Underground personnel do not need to directly contact the agent, further improving construction safety. By pre-loading the static fracturing agent into the cartridge to form a fracturing rod that can be retained in the borehole, it is small in size and light in weight and can be carried by a single coal miner. The installation is simple and convenient, which simplifies the construction steps and saves construction time.

[0021] (4) By pre-loading the static fracturing powder into the cartridge, it can be retained in the borehole for a period of time. When expansion and rock breaking are required, water can be injected. The static fracturing powder absorbs water and can be conveniently injected into the borehole where the fracturing rod is installed to cause fracturing according to the engineering conditions. The sealed fracturing rod structure can prevent moisture and water in the borehole from causing premature reaction of the fracturing rod, simplifying the construction steps and saving construction time.

[0022] (5) The borehole diameter and layout can be scientifically and rationally designed based on the coal seam lithology distribution, on-site construction and production progress. This fracturing rod can also adapt to changes in borehole diameter. Under the same engineering conditions, increasing the borehole diameter can reduce the number of holes drilled, saving engineering work and the amount of fracturing agent used.

[0023] (6) The outer cylinder, inner cylinder, upper constraint end cover and lower constraint end cover are manufactured with a split structure, which is very convenient and quick to manufacture and install. During installation, the lower end of the inner cylinder is inserted into the annular groove in the lower constraint end cover, and then the lower end of the outer cylinder is put on the annular step on the outer circle of the lower constraint end cover. Then, the static cracking powder is filled into the annular cavity between the outer cylinder and the inner cylinder. After filling and compacting, the constraint end cover is installed on the upper end of the outer cylinder and the inner cylinder, so that the upper end of the inner cylinder is inserted into the annular groove on the bottom surface of the upper constraint end cover, and the annular step on the outer circle of the bottom surface of the upper constraint end cover cooperates with the upper end of the outer cylinder. This installation structure limits the upper and lower ends of the outer cylinder and the inner cylinder in the radial direction, making it more stable and reliable during assembly.

[0024] In summary, the utility model manufactures and installs the outer cylinder, inner cylinder, upper constraint end cover and lower constraint end cover with a split structure, which makes it convenient to adjust the diameters of the outer cylinder and the inner cylinder according to the diameter of the drilled hole, thereby solving the problem of easy spraying when used for large-diameter drilling (above Φ50mm). It not only maintains the advantages of static fracturing technology such as no vibration, no open flame, and no harmful gas, but also improves the fracturing ability and expands its application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the appearance structure of the utility model;

[0026] Figure 2 It is a schematic diagram of the explosion structure of the utility model;

[0027] Figure 3 It is an exploded view of the loaded cartridge;

[0028] Figure 4 is a top view of the lower constraint end cap;

[0029] Figure 5 It is a bottom view of the lower restraint end cap;

[0030] Figure 6 yes Figure 5 Middle AA section view. DETAILED DESCRIPTION

[0031] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples.

[0032] like Figures 1-6 As shown, the utility model is a controllable strong static fracturing rod, comprising a plurality of cartridges 1 connected vertically end to end, a water pipe 2 is coaxially arranged inside the cartridges 1, and a plurality of water-permeable holes 3 are opened on the water pipe 2, all of which are connected to the interior of the cartridges 1. Connectors for compressing all the serially connected cartridges 1 are provided at the upper and lower ends of the water pipe 2, and a guide head 4 is provided at the upper end of the water pipe 2;

[0033] The charging barrel 1 comprises an outer cylinder 5, an inner cylinder 6, an upper constraint end cover 7 and a lower constraint end cover 8 arranged coaxially, the upper constraint end cover 7 and the lower constraint end cover 8 are the same in structure and are arranged symmetrically, a circular hole 9 for penetrating the water pipe 2 is arranged at the center of the upper constraint end cover 7 and the lower constraint end cover 8, the diameter of the circular hole 9 is equal to the outer diameter of the water pipe 2, the inner diameter of the inner cylinder 6 is greater than the diameter of the circular hole 9, a water-permeable seam 10 is arranged on the inner cylinder 6, an annular groove 11 is arranged on the bottom surface of the upper constraint end cover 7 and the top surface of the lower constraint end cover 8, an annular step 12 is arranged on the outer edge of the bottom surface of the upper constraint end cover 7 and the top surface of the lower constraint end cover 8, the upper end and the lower end of the inner cylinder 6 are respectively inserted into the annular groove 11 of the upper constraint end cover 7 and the annular groove 11 of the lower constraint end cover 8, and the upper end and the lower end of the outer cylinder 5 are respectively assembled onto the annular step 12 of the upper constraint end cover 7 and the annular step 12 of the lower constraint end cover 8; and the annular cavity formed between the inner circle of the outer cylinder 5 and the outer circle of the inner cylinder 6 is filled with static cracking powder.

[0034] The outer circle of the upper end of the guide head 4 is a conical surface 16 which is thin at the top and thick at the bottom, and a mounting hole for penetrating the water pipe 2 is arranged at the center of the guide head 4;

[0035] The water pipe 2 is a threaded steel pipe, the connecting piece comprises a fastening nut 13 and a pad plate 14, the pad plate 14 is sleeved on the water pipe 2, and the fastening nut 13 is threadedly connected on the water pipe 2;

[0036] The fastening nut 13 of the connecting piece at the lower end tightly presses the pad plate 14 to the bottom surface of the lower constraint end cover 8 at the lowermost end;

[0037] The pad plate 14 and the fastening nut 13 of the connecting piece at the upper end are provided with the guide head 4, and the fastening nut 13 tightly presses the pad plate 14 to the top surface of the upper constraint end cover 7 at the uppermost end through the guide head 4.

[0038] The guide head 4 and the outer part of all the section charging barrels 1 are provided with a through-length sealing rubber sleeve 15, and the conical surface 16 at the upper end of the guide head 4 is wrapped by the sealing rubber sleeve 15 after heat shrinkage.

[0039] Two anti-skid steel sheets 17 are fixedly arranged on the outer circle of the guide head 4, the two anti-skid steel sheets 17 are symmetrically arranged about the center line of the guide head 4, the two anti-skid steel sheets 17 both extend out of the sealing rubber sleeve 15, the upper end of the anti-skid steel sheet 17 is fixedly connected with the outer circle of the guide head 4, and the length direction of the anti-skid steel sheet 17 forms an acute angle with the center line of the guide head 4.

[0040] The working principle and the technical effect of the utility model are as follows:

[0041] (1) When in use, it is only necessary to connect multiple static fracturing rods to the two ports of the water pipe through the connection and then install them into the borehole. When the borehole opening is sealed, a water injection pipe must be reserved. The upper end of the water injection pipe is connected to the lower end of the water pipe 2 in the lowest static fracturing rod. When reaction fracturing is required, water can be injected into the borehole through the water injection pipe. When the static fracturing rod is installed in the borehole, the two anti-skid steel plates 17 are compressed under their own elasticity and move upward along the borehole. After the fracturing rod is installed in place, the anti-skid steel plates 17 are unfolded and the lower end of the anti-skid steel plates 17 is inserted into the inner wall of the borehole, which can ensure that the static fracturing rod will not slide down.

[0042] (2) The annular cavity formed between the outer cylinder 5 and the inner cylinder 6 is filled with a static fracturing agent. The diameters of the outer cylinder 5 and the inner cylinder 6 can be adjusted proportionally. The inner diameter of the inner cylinder 6 is larger than the diameter of the water pipe 2. The outer diameter d1 of the water pipe 2, the inner diameter D of the outer cylinder 5, and the outer diameter d2 of the inner cylinder 6 are such that D> d2> d1. The inner cylinder 6 is made of metal and has a water-permeable slit 10. The space between the outer cylinder 5 and the inner cylinder 6 is filled with the fracturing agent. Depending on the specific borehole diameter, the sizes of d2 and D can be adjusted proportionally to achieve the goal of fracturing in large-diameter boreholes while keeping the amount of fracturing powder installed within a reasonable range to avoid blowouts. Since the present invention can be installed in boreholes larger than 50 mm, it has a strong fracturing ability.

[0043] After water is introduced into the water pipe 2, the permeable holes 3 on the water pipe 2 are used to inject water into the inner cylinder 6. Clean water enters through the permeable slits 10 in the inner cylinder 6 and is adsorbed by the static fracturing agent. The fracturing agent absorbs water and reacts, subsequently generating a gradually increasing expansion stress. After 24 hours, the expansion stress exceeds 38 MPa, capable of fracturing most coal and rock masses. The proportional design of the diameters of the outer cylinder 5 ensures that the installed amount of fracturing agent is within a reasonable range. Furthermore, the water storage space between the inner cylinder 6 and the water pipe 2 is filled with clean water, which also absorbs a large amount of heat, thus avoiding the problem of spray holes caused by large-diameter drilling fracturing agents.

[0044] (3) The static fracturing powder is compacted to a certain density and loaded into the cartridge 1. During the storage and transportation of the fracturing rod, sealing caps 18 are respectively provided at the two ends of the water pipe 2. This makes the entire static fracturing rod a fully enclosed packaging structure, and underground workers do not need to directly contact the agent, further improving construction safety. By pre-loading the static fracturing agent into the cartridge to form a fracturing rod that can be retained in the borehole, it is small in size and light in weight and can be carried by a single coal miner. The installation is simple and convenient, which simplifies the construction steps and saves construction time.

[0045] (4) By pre-loading the static fracturing powder into the cartridge 1, it can be retained in the borehole for a period of time, and water can be injected when expansion and rock breaking are required. The static fracturing powder absorbs water and can be conveniently injected into the borehole where the fracturing rod is installed to cause fracturing according to the engineering situation. The sealed fracturing rod structure can prevent moisture and water in the borehole from causing the fracturing rod to react prematurely, thereby simplifying the construction steps and saving construction time.

[0046] (5) The borehole diameter and layout can be scientifically and rationally designed based on the coal seam lithology distribution, on-site construction and production progress. This fracturing rod can also adapt to changes in borehole diameter. Under the same engineering conditions, increasing the borehole diameter can reduce the number of holes drilled, saving engineering work and the amount of fracturing agent used.

[0047] (6) The outer cylinder 5, inner cylinder 6, upper constraint end cover 7 and lower constraint end cover 8 are manufactured with a split structure, which is very convenient and quick to manufacture and install. During installation, the lower end of the inner cylinder 6 is inserted into the annular groove 11 in the lower constraint end cover 8, and then the lower end of the outer cylinder 5 is put on the annular step 12 on the outer circle of the lower constraint end cover 8. Then, the static fracturing powder is filled into the annular cavity between the outer cylinder 5 and the inner cylinder 6. After filling and compacting, the upper constraint end cover 7 is installed on the upper ends of the outer cylinder 5 and the inner cylinder 6, so that the upper end of the inner cylinder 6 is inserted into the annular groove 11 on the bottom surface of the upper constraint end cover 7, and the annular step 12 on the outer circle of the bottom surface of the upper constraint end cover 7 cooperates with the upper end of the outer cylinder. This installation structure limits the upper and lower ends of the outer cylinder 5 and the inner cylinder 6 in the radial direction, making them more stable and reliable during assembly.

[0048] The above embodiments illustrate the basic principles and features of the present invention. However, the above merely illustrates preferred embodiments of the present invention and is not intended to limit the present invention to the embodiments described. Persons skilled in the art, inspired by this patent, may make various modifications and improvements without departing from the spirit of the present invention and the scope of protection of the claims, all of which fall within the scope of protection of the present invention. Therefore, the patent and scope of protection of this utility model shall be subject to the appended claims.

Claims

1. A controllable strong static cracking rod, characterized by: It comprises a plurality of cartridges connected in sequence vertically end to end, a water pipe is coaxially arranged inside the cartridge, a plurality of water-permeable holes are opened on the water pipe, and connectors for pressing all the serially connected cartridges are provided at the upper and lower ends of the water pipe, and a guide head is provided at the upper end of the water pipe; The drug-loading cartridge includes an outer cylinder body, an inner cylinder body, an upper constraint end cover and a lower constraint end cover which are coaxially arranged. The upper constraint end cover and the lower constraint end cover have the same structure and are symmetrically arranged up and down. A circular hole for passing a water pipe is provided in the center of the upper constraint end cover and the lower constraint end cover. The diameter of the circular hole is equal to the outer diameter of the water pipe. The inner diameter of the inner cylinder is larger than the diameter of the circular hole. A water-permeable seam is provided on the inner cylinder body. An annular groove is provided on the bottom surface of the upper constraint end cover and the top surface of the lower constraint end cover. An annular step is provided on the outer edge of the bottom surface of the upper constraint end cover and the top surface of the lower constraint end cover. The upper and lower ends of the inner cylinder body are respectively assembled and inserted into the annular groove of the upper constraint end cover and the annular groove of the lower constraint end cover. The upper and lower ends of the outer cylinder body are respectively assembled onto the annular steps of the upper constraint end cover and the annular steps of the lower constraint end cover; the annular cavity formed between the inner circle of the outer cylinder and the outer circle of the inner cylinder is filled with static fracturing powder.

2. A controllable strong static cracking rod according to claim 1, characterized in that: The outer circle of the upper end of the guide head is a conical surface that is thinner at the top and thicker at the bottom. A mounting hole for passing a water pipe is opened in the center of the guide head. The water pipe is made of threaded steel pipe, and the connecting parts include fastening nuts and pads. The pads are sleeved on the water pipe, and the fastening nuts are threadedly connected to the water pipe. The fastening nut of the connector at the lower end presses the backing plate tightly against the bottom surface of the lower restraint end cover at the lowest end; The guide head is provided between the pad of the upper connecting piece and the fastening nut, and the fastening nut presses the pad to the top surface of the upper constraint end cover through the guide head.

3. The controllable strong static cracking rod according to claim 2, characterized in that: A full-length sealing rubber sleeve is provided on the outside of the guide head and all the segmented cartridges. The upper end of the sealing rubber sleeve is wrapped around the conical surface at the upper end of the guide head after heat shrinkage.

4. A controllable strong static cracking rod according to claim 1 or 2, characterized in that: Two anti-slip steel plates are fixed on the outer circle of the guide head. The two anti-slip steel plates are symmetrically arranged about the center line of the guide head. Both anti-slip steel plates extend out of the sealing rubber sleeve. The upper end of the anti-slip steel plate is fixedly connected to the outer circle of the guide head. The angle between the length direction of the anti-slip steel plate and the center line of the guide head is an acute angle.

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