A transient high-pressure gas impact destruction coal rock microstructure test device and use method

Abstract

The present invention discloses a test device for destroying coal and rock microstructures by transient high-pressure pneumatic impact, comprising a pneumatic impact kettle, a fracturing tube, an excitation component, a first gas injection tube, a three-way joint, a high-pressure needle valve, a first temperature sensor, a second temperature sensor, a pressure sensor, a lower limiting ring, an upper limiting ring, an injection-molded sealing cover and a sealing component. The present invention also discloses a method for using the test device for destroying coal and rock microstructures by transient high-pressure pneumatic impact. The present invention can achieve impact destruction of the microstructure of coal and rock samples by transient high-pressure gas, and provide experimental support for subsequent research on the laws and mechanisms of sample microstructure destruction by impact, and at the same time can achieve real-time and accurate monitoring of gas temperature and pressure during the fracturing impact process, and then analyze the relationship between the fracturing effect and the fracturing energy under different conditions, and provide an experimental research basis for achieving the goals of precise fracturing and efficient fracturing of transient high-pressure pneumatic impact fracturing technology.

Description

Technical Field

[0001] The invention relates to a transient high-pressure gas-force impact destruction coal-rock microstructure test device and a use method, belonging to the technical field of gas fracturing. Background Art

[0002] As a relatively new type of physical blasting fracturing technology, gas fracturing technology is increasingly widely used in coal seam fracturing and permeability enhancement, shale gas production enhancement, rock excavation and other fields. This technology uses the aerodynamic impact of transient high-pressure gas release to fracture the target. Compared with the traditional explosive blasting fracturing method, gas fracturing technology has the characteristics of high safety, small impact disturbance and good fracturing effect.

[0003] A large number of research results have been achieved on the effects of gas fracturing on the permeability and production enhancement of different types of coal and rock, as well as the macroscopic physical characteristics of the crack propagation law of the impacted coal and rock specimens. However, there is a lack of research on the destruction law and destruction mechanism of the microstructure (mainly pore structure) of the target sample caused by the impact of transient high-pressure gas, and such research is of great significance to revealing the microscopic mechanism of transient high-pressure gas-driven permeability enhancement.

[0004] The objects of the currently common transient high-pressure pneumatic impact fracture test device are generally block samples, which are mainly used to study the change law of the macroscopic physical characteristics of the test block after impact. Although the test block after impact can also be refined to study the change of its microcracks, the impact of transient high-pressure pneumatic force on the microstructure of coal and rock samples generally exists at the micro-nano level. Therefore, compared with the impact of powder or granular samples with smaller particle size, its effect is insufficient and the workload is large. Based on this, it is of high practical value to develop a transient high-pressure pneumatic impact fracture device suitable for powder or granular samples. Summary of the invention

[0005] In view of the above problems, the present invention provides a test device for destroying the microstructure of coal and rock by transient high-pressure gas impact, which can realize the impact destruction of the microstructure of coal and rock samples by transient high-pressure gas, and provide experimental support for the subsequent research on the laws and mechanisms of the impact effect on the microstructure of the samples. At the same time, it can realize real-time and accurate monitoring of the gas temperature and pressure during the fracturing impact process, and then analyze the relationship between the fracturing effect and the fracturing energy under different conditions, and provide an experimental research basis for achieving the goals of precise fracturing and efficient fracturing of transient high-pressure gas impact fracturing technology.

[0006] At the same time, the present invention provides a method for using a transient high-pressure pneumatic impact destruction coal rock microstructure test device, which is safe, highly reliable and easy to operate.

[0007] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0008] A transient high-pressure pneumatic impact destruction of coal and rock microstructure test device, comprising a cylindrical pneumatic impact kettle; a first upper end cover and a first lower end cover are movably connected to the upper and lower ends of the pneumatic impact kettle respectively; a first temperature sensor is arranged in the middle of the side wall of the pneumatic impact kettle;

[0009] A fracturing tube is arranged inside the pneumatic impact kettle, and a second upper end cover and a second lower end cover are movably connected to the upper and lower ends of the fracturing tube respectively; the second upper end cover is connected to an excitation member suspended inside the fracturing tube through a first wire; a second temperature sensor is also arranged on the second upper end cover; the second lower end cover is connected to the inner section of the first gas injection pipe, and the first gas injection pipe passes through the first lower end cover outwards and is connected to a pressure sensor and a high-pressure needle valve respectively through a three-way joint, and the high-pressure needle valve is connected to the gas injection device;

[0010] A weak portion is obtained by cutting in the middle of the outer wall of the fracturing tube; an upper limiting ring and a lower limiting ring are arranged between the inner wall of the pneumatic impact kettle and the outer wall of the fracturing tube, and a space for compacting powdered or granular coal rock samples is formed between the outer wall of the weak portion, the inner wall of the pneumatic impact kettle, the lower surface of the upper limiting ring and the upper surface of the lower limiting ring;

[0011] The first temperature sensor, the second temperature sensor and the pressure sensor are all connected to a data acquisition instrument, and the data acquisition instrument is connected to a computer;

[0012] The first conducting wire is connected to an excitation device.

[0013] Furthermore, the first conductive wire comprises a single-core copper conductive wire with an insulating layer.

[0014] Furthermore, the gas injection device, the first temperature sensor, the second temperature sensor, the pressure sensor, the data acquisition instrument and the computer are all connected to a power source.

[0015] Furthermore, the pneumatic impact kettle is made of high-pressure resistant stainless steel.

[0016] Furthermore, the pipe body of the fracturing pipe is made of a seamless steel pipe.

[0017] Furthermore, the excitation component is composed of an energy concentrator and an ignition head; the ignition head is buried in the center of the energy concentrator, and the ignition head is connected to the first wire.

[0018] Furthermore, the first gas injection pipe is a stainless steel gas pipe; the upper limiting ring and the lower limiting ring are both made of iron.

[0019] A transient high-pressure pneumatic impact destruction coal rock microstructure test device, comprising a cylindrical pneumatic impact kettle;

[0020] The upper and lower ends of the pneumatic impact kettle are both first connecting ends;

[0021] The inner wall of the first connection end and the inner wall of the pneumatic impact kettle form a step shape; the inner diameter of the first connection end is larger than the inner diameter of the middle part of the pneumatic impact kettle;

[0022] The first connecting end is provided with a thread;

[0023] A first upper end cover and a first lower end cover are respectively threadedly connected to the upper and lower ends of the pneumatic impact kettle;

[0024] The first upper end cover and the first lower end cover are both stepped truncated cone-shaped, and the first upper end cover includes a primary truncated cone located at the upper end and a secondary truncated cone located at the lower end, which are integrally connected; the diameter of the primary truncated cone is smaller than the diameter of the secondary truncated cone, the secondary truncated cone is threadedly connected to the first connecting end, and the first connecting end located below the secondary truncated cone is connected to the injection-molded sealing cover;

[0025] Four second wires are embedded through the center of the injection-molded sealing cover;

[0026] The first lower end cover comprises a three-stage truncated cone which is integrally connected and located at the upper end and contacts the inner wall of the pneumatic impact kettle, and a four-stage truncated cone which is located at the lower end and is threadedly connected to the first connecting end;

[0027] A first annular groove is provided on the outer wall of the three-stage truncated cone, and a first sealing member is provided in the first annular groove;

[0028] The first upper end cover is penetrated by a wire lead-out hole;

[0029] The first lower end cover is provided with a first gas injection pipe hole and a first threaded hole which are connected from top to bottom;

[0030] The side wall of the pneumatic impact kettle is provided with a first temperature sensor interface;

[0031] The first temperature sensor interface is provided with a first temperature sensor, the first temperature sensor is connected to a data acquisition instrument, and the data acquisition instrument is connected to a computer;

[0032] A cylindrical fracturing tube is arranged inside the pneumatic impact kettle;

[0033] The upper and lower ends of the fracturing tube are both second connecting ends;

[0034] The second connecting end is provided with a thread;

[0035] The inner wall of the second connecting end and the inner wall of the fracturing tube form a step shape; the inner diameter of the second connecting end is larger than the inner diameter of the middle part of the fracturing tube;

[0036] A second upper end cover and a second lower end cover are respectively threadedly connected to the upper and lower ends of the fracturing tube;

[0037] The second upper end cover and the second lower end cover are both stepped truncated cone-shaped, and the second upper end cover comprises a five-level truncated cone which is integrally connected, located at the upper end and threadedly connected to the second connecting end, and a six-level truncated cone which is located at the lower end and contacts the inner wall of the fracturing tube;

[0038] The second lower end cover comprises a seven-stage truncated cone which is integrally connected and located at the upper end and contacts the inner wall of the fracturing tube, and an eight-stage truncated cone which is located at the lower end and is threadedly connected to the second connecting end;

[0039] A second annular groove and a third annular groove are respectively provided on the outer walls of the six-stage truncated cone and the seven-stage truncated cone, and a second sealing member and a third sealing member are respectively provided in the second annular groove and the third annular groove;

[0040] The middle part of the outer wall of the fracture-causing tube is cut to obtain a weak part;

[0041] The lower part of the second upper end cover is symmetrically provided with two wire holes for passing the first wire, and the two wire holes are respectively extended upward to form a second threaded hole and a third threaded hole;

[0042] A second temperature sensor interface is provided through the center of the second upper end cover;

[0043] A second temperature sensor is disposed in the second temperature sensor interface;

[0044] A second gas injection pipe hole is opened at the central upper part of the second lower end cover, and a fourth threaded hole is opened at the central lower part of the second lower end cover, and the second gas injection pipe hole is connected to the fourth threaded hole;

[0045] An excitation member is arranged inside the fracturing tube;

[0046] The excitation component is composed of an energy concentrator and an ignition head;

[0047] The first wire is connected to the ignition head and then passes through the second upper end cover and is connected to the second wire on the injection-molded sealing cover. The second wire is also connected to the lead of the second temperature sensor. The upper end of the second wire passes through the wire lead-out hole and is respectively connected to the excitation device and the data acquisition instrument.

[0048] The injection-molded sealing cover is a stepped truncated cone type, and comprises a nine-stage truncated cone which is integrally connected, located at the upper end and in contact with the first connecting end, and a ten-stage truncated cone which is located at the lower end and in contact with the inner wall of the pneumatic impact kettle, and a fourth annular groove is provided on the outer wall of the ten-stage truncated cone, and a fourth sealing member is provided in the fourth annular groove;

[0049] Sealing gaskets are provided in the first threaded hole, the second threaded hole, the third threaded hole and the fourth threaded hole;

[0050] Sealing bolts are provided at the exits of the first threaded hole, the second threaded hole, the third threaded hole and the fourth threaded hole;

[0051] The sealing gasket and the sealing bolt are both provided with an axial through hole;

[0052] A first gas injection pipe sequentially passes through the first lower end cover and the second lower end cover and opens into the interior of the fracturing tube;

[0053] One end of the three-way connector is connected to the outer end of the first gas injection pipe led out from the pneumatic impact kettle; one end is connected to the pressure sensor through the second gas injection pipe; one end is connected to one port of the high-pressure needle valve through the third gas injection pipe, and the other port of the high-pressure needle valve is connected to the gas injection device through the fourth gas injection pipe;

[0054] An upper limiting ring and a lower limiting ring are arranged between the inner wall of the pneumatic impact kettle and the outer wall of the fracturing tube, and a space for compacting powdered or granular coal rock samples is formed between the outer wall of the weak portion, the inner wall of the pneumatic impact kettle, the lower surface of the upper limiting ring and the upper surface of the lower limiting ring.

[0055] Furthermore, the first conductor comprises a single-core copper conductor with an insulating layer; the second conductor comprises an enameled copper conductor; the gas injection device, the first temperature sensor, the second temperature sensor, the pressure sensor, the data acquisition instrument and the computer are all connected to a power supply; the upper and lower limiting rings are both made of iron; the first seal, the second seal, the third seal and the fourth seal are all O-rings.

[0056] A method for using a transient high-pressure pneumatic impact destruction coal rock microstructure test device comprises the following steps:

[0057] Step 1: Tighten the first lower end cover of the pneumatic impact kettle; fix the pneumatic impact kettle vertically and keep it suspended up and down; fix the first temperature sensor on the first temperature sensor interface;

[0058] Step 2: fix the second temperature sensor to the second temperature sensor interface; take two first wires, pass them through the sealing gasket and the sealing bolts respectively and fix them to the wire holes of the second upper end cover of the fracturing tube; connect the first wires led out from the lower surface of the second upper end cover to the excitation member; lead the two leads of the second temperature sensor upward; tighten the second upper end cover to the upper pipe opening of the fracturing tube;

[0059] Step 3: Cut a section of the first gas injection pipe, pass it through the sealing gasket and the sealing bolt, and fix it on the second lower end cover; tighten the second lower end cover to the lower pipe opening of the fracturing pipe;

[0060] Step 4: insert the fracturing tube through the upper opening of the pneumatic impact kettle, and at the same time, pass the first gas injection tube fixed in the second lower end cover through the first gas injection tube hole in the center of the first lower end cover and lead out; keep the fracturing tube at the bottom center of the pneumatic impact kettle; insert the lower limit ring; fix the first gas injection tube to the first lower end cover with a sealing gasket and a sealing bolt;

[0061] Step 5: Add the pre-prepared coal and rock samples around the weak part of the fracturing tube until the samples are flush with the top of the weak part; insert the upper limit ring and compact the samples;

[0062] Step 6: Connect the wires led out from the upper end of the second temperature sensor to the four second wires led out from the lower surface of the injection-molded sealing cover according to the corresponding relationship; put the injection-molded sealing cover in;

[0063] Step 7: Tighten the first upper end cover, and at the same time, lead out the second wire extending from the upper surface of the injection-molded sealing cover from its wire lead-out hole and connect it to the external wire; connect the external wire to the excitation device and the data acquisition instrument respectively;

[0064] Step 8: Connect the outer end of the second gas injection pipe to the three-way joint; connect the pressure sensor to the three-way joint through the second gas injection pipe, and connect the pressure sensor to the data acquisition instrument, and connect the data acquisition instrument to the computer; take a high-pressure needle valve, one end of which is connected to the three-way joint through the third gas injection pipe, and the other end is connected to the gas injection device;

[0065] Step 9: Turn on the computer to monitor the pressure in the fracturing tube in real time; open the high-pressure needle valve to inject the test gas into the fracturing tube; close the high-pressure needle valve after the gas pressure in the fracturing tube reaches a predetermined value, and observe whether the pressure in the fracturing tube remains stable; when the pressure in the fracturing tube is stable, ignite the excitation element through an external excitation device to cause the fracturing tube to rupture.

[0066] The present invention has the following beneficial effects:

[0067] (1) The components of the test device of the present invention have simple structures, low manufacturing costs, and are easy to assemble and disassemble. The system principle is simple and easy to understand. The good sealing system and the restrictions on the fracturing area of ​​the fracturing tube and the distribution area of ​​the sample ensure the reliability of the test data and the obtained samples. After the test is completed, except for the trigger, the fracturing tube and the sealing gasket, the remaining components can be reused, which effectively reduces the cost of a single test.

[0068] (2) The setting of temperature sensors can monitor the temperature changes inside the fracturing tube and the sample in real time during the test. The setting of pressure sensors can realize real-time dynamic monitoring of the gas pressure inside the fracturing tube before fracturing and inside the pneumatic impact kettle after fracturing. Combined with the test data of the temperature sensor, on the one hand, it can realize real-time and accurate monitoring of the gas temperature and pressure before and after fracturing. On the other hand, it can also obtain different fracturing effects under different impact pressures through in-depth analysis of the data, and then obtain the optimal fracturing pressure under different coal rock hardness, different pore characteristics and other parameters. Furthermore, it provides an experimental research basis for realizing accurate and efficient fracturing.

[0069] (3) According to the experimental requirements, the control variables can be achieved by adjusting the thickness of the weak part of the fracturing tube, the gas injection pressure, or the amount of the energy-gathering agent while keeping the parameters of the other components unchanged, so as to obtain samples with different degrees of damage to the coal rock microstructure under different fracturing conditions. The adjustment method is simple and easy, which is conducive to subsequent in-depth research. BRIEF DESCRIPTION OF THE DRAWINGS

[0070] Figure 1 It is a schematic diagram of the system structure of the test device in the present invention;

[0071] Figure 2 It is a structural schematic diagram of the present invention;

[0072] Figure 3 It is a schematic diagram of the structure of the pneumatic impact kettle in the present invention;

[0073] Figure 4 It is a schematic diagram of the structure of the fracturing tube in the present invention. DETAILED DESCRIPTION

[0074] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0075] Example 1

[0076] like Figure 1As shown, a transient high-pressure pneumatic impact destruction of coal and rock microstructure test device includes a pneumatic impact kettle 1, a fracturing tube 2, an excitation component 3, a first gas injection pipe 4, a three-way connector 5, a high-pressure needle valve 6, a first temperature sensor 9, a second temperature sensor 10, a pressure sensor 7, a lower limiting ring 8, an upper limiting ring 11, an injection molding sealing cover 12 and a sealing component.

[0077] like Figure 1 As shown, a fracturing tube 2 is provided inside the pneumatic impact kettle 1, and an excitation member 3 is provided inside the fracturing tube 2. The excitation member 3 is connected to an excitation device through a first wire 13. In this embodiment, the excitation device is a detonator. The inside of the fracturing tube 2 is connected to a three-way joint 5 through a first gas injection pipe 4. The three-way joint 5 is also respectively connected to a high-pressure needle valve 6 and a pressure sensor 7. The high-pressure needle valve 6 is connected to the gas injection device, and the gas injection device can inject air, liquid nitrogen or CO2.

[0078] A first temperature sensor 9 is arranged on the side wall of the pneumatic impact kettle 1, and a second temperature sensor 10 is arranged on the top of the fracturing tube 2. The first temperature sensor 9, the second temperature sensor 10 and the pressure sensor 7 are respectively connected to a data acquisition instrument, and the data acquisition instrument is connected to a computer.

[0079] A weak portion 2-8 is obtained by cutting in the middle of the outer wall of the fracturing tube 2; an upper limiting ring 11 and a lower limiting ring 8 are arranged between the inner wall of the pneumatic impact kettle 1 and the outer wall of the fracturing tube 2, and a space for compacting powdered or granular coal rock samples is enclosed by the outer wall of the weak portion 2-8, the inner wall of the pneumatic impact kettle 1, the lower surface of the upper limiting ring 11 and the upper surface of the lower limiting ring 8.

[0080] The outer wall of the pneumatic impact kettle 1 is suspended and fixed by a bracket.

[0081] The pneumatic impact kettle 1 is made of stainless steel, with an outer diameter of 110 mm, a wall thickness of 15 mm, and a height of 220 mm.

[0082] The body of the crack-causing pipe 2 is made of a seamless steel pipe with an outer diameter of 48 mm, a wall thickness of 3 mm, and a height of 100 mm, and the material is 20 steel.

[0083] The ignition element 3 is composed of an energy-gathering agent and an ignition head. The amount of the energy-gathering agent is 4 g, and the ignition head is connected to a first wire 13. The first wire 13 is preferably a single-core copper wire with an insulation layer.

[0084] The first gas injection pipe 4 is a stainless steel gas pipe with an outer diameter of 3 mm.

[0085] The inner diameter of the upper limiting ring 11 and the lower limiting ring 8 are both 48.5 mm, the outer diameter is both 79.5 mm, the height of the upper limiting ring 11 is 45 mm, and the height of the lower limiting ring 8 is 35 mm. The material of the upper limiting ring 11 and the lower limiting ring 8 is preferably iron.

[0086] Example 2

[0087] like Figure 2 As shown, a transient high-pressure pneumatic impact destruction of coal and rock microstructure test device includes a pneumatic impact kettle 1, a fracturing tube 2, an excitation component 3, a first gas injection pipe 4, a three-way connector 5, a high-pressure needle valve 6, a first temperature sensor 9, a second temperature sensor 10, a pressure sensor 7, a lower limiting ring 8, an upper limiting ring 11, an injection molding sealing cover 12 and a sealing component.

[0088] like Figure 3 As shown, the pneumatic impact kettle 1 is made of stainless steel, with an outer diameter of 110mm, a wall thickness of 15mm and a height of 220mm, and is connected to the first upper end cover 1-1 and the first lower end cover 1-2 by threads; the wire lead-out hole 1-6 located in the center on the first upper end cover 1-1 has a diameter of 10mm; the first air injection pipe hole 1-7 in the upper center of the first lower end cover 1-2 has a diameter of 3mm, and a first threaded hole 1-4 is opened in the lower center, the first air injection pipe hole 1-7 and the first threaded hole 1-4 are connected and the axes coincide; the diameter of the non-threaded part of the first lower end cover 1-2 is 70mm, and the groove width of the first annular groove 1-5 thereon is 2.4mm and the groove depth is 1.8mm; a first temperature sensor interface 1-3 is arranged on the side wall of the pneumatic impact kettle 1, and the size is adapted to the first temperature sensor 9, which is specifically arranged at the center of the vertical direction of the side wall of the pneumatic impact kettle 1.

[0089] like Figure 4 As shown, the body of the fracturing tube 2 is made of a seamless steel tube with an outer diameter of 48 mm, a wall thickness of 3 mm, and a height of 100 mm, and the material is 20 steel; it is connected to the second upper end cover 2-1 and the second lower end cover 2-2 by threads; the outer wall of the fracturing tube 2 is cut to obtain a weak part 2-8 with a wall thickness of 1.5 mm and a height of 5 mm, and the distance from the upper and lower ports is 25 mm; two wire holes 2-10 for passing a single-core copper wire with an insulating layer (i.e., the first wire 13) are symmetrically opened at the lower part of the second upper end cover 2-1, and the aperture of the wire hole 2-10 is the same as the diameter of the single-core copper wire and is 3 mm; two threaded holes (i.e., the second threaded holes 13) are extended upward from the two wire holes 2-10 The second upper end cover 2-1 has a second temperature sensor interface 2-9, the size of which is adapted to the second temperature sensor 10; the second gas injection pipe hole 2-11 at the upper center of the second lower end cover 2-2 has a diameter of 3mm, and a fourth threaded hole 2-3 is opened at the lower center, the second gas injection pipe hole 2-11 is connected to the fourth threaded hole 2-3 and the axes coincide; the diameter of the non-threaded part of the second upper end cover 2-1 and the second lower end cover 2-2 is the same as the inner diameter of the fracturing tube 2, which is 42mm, and the groove width of the second annular groove 2-6 and the third annular groove 2-7 thereon is 2.4mm, and the groove depth is 1.8mm.

[0090] like Figure 2 As shown, the excitation member 3 is composed of an energy-gathering agent and an ignition head. The amount of energy-gathering agent is 4g, and the ignition head is connected to a single-core copper wire. The first gas injection pipe 4 is a stainless steel gas pipe with an outer diameter of 3mm. One end of the three-way connector 5 is connected to the outer end of the first gas injection pipe 4 led out from the pneumatic impact kettle 1; one end is connected to the pressure sensor 7 through the second gas injection pipe; one end is connected to the high-pressure needle valve 6 through the third gas injection pipe, and the other end of the high-pressure needle valve 6 is connected to the gas injection device through the fourth gas injection pipe. The first temperature sensor 9, the second temperature sensor 10 and the pressure sensor 7 are all high-precision, high-sampling rate sensors. The inner diameter of the upper limiting ring 11 and the lower limiting ring 8 are both 48.5mm, and the outer diameter is 79.5mm. The height of the upper limiting ring 11 is 45mm, and the height of the lower limiting ring 8 is 35mm. The injection-molded sealing cover 12 is made of hard, dense and airtight injection-molded material, and four enameled copper wires (i.e., the second wire 17) are embedded in the center; the lower end of the second wire 17 is respectively connected to the single-core copper wire and the lead of the second temperature sensor 10, and the upper end is led out and connected to the external wire, and then connected to the excitation device and the data acquisition instrument respectively; the diameter of the upper half of the injection-molded sealing cover 12 is the same as the outer diameter of the first upper end cover 1-1 of the pneumatic impact kettle 1, and there is no thread on it, and the diameter of the lower half is 70mm, and a fourth annular groove 18 is opened on it, and the groove width and groove depth are 2.4mm and 1.8mm respectively. The sealing parts include O-rings, sealing gaskets 14, 15 and 16, and sealing bolts 19, 20 and 21; the sizes of the sealing rings are respectively adapted to the sizes of the corresponding annular grooves; the centers of the sealing bolts 19, 20 and 21 are all provided with axial through holes with a diameter of 3mm; the materials of the sealing gaskets 14, 15 and 16 are all polytetrafluoroethylene.

[0091] Example 3

[0092] like Figure 1~Figure 4 As shown, a transient high-pressure pneumatic impact destruction of coal and rock microstructure test device comprises a cylindrical pneumatic impact kettle 1; both upper and lower ends of the pneumatic impact kettle 1 are first connecting ends; the inner wall of the first connecting end forms a step with the inner wall of the pneumatic impact kettle 1; the inner diameter of the first connecting end is larger than the inner diameter of the middle part of the pneumatic impact kettle 1; the first connecting end is provided with a thread; the first upper end cover 1-1 and the first lower end cover 1-2 are respectively threadedly connected to the upper and lower ends of the pneumatic impact kettle 1;

[0093] The first upper end cover 1-1 and the first lower end cover 1-2 are both stepped truncated cones. The first upper end cover 1-1 includes an integrally connected primary truncated cone located at the upper end and a secondary truncated cone located at the lower end. The diameter of the primary truncated cone is smaller than the diameter of the secondary truncated cone. The secondary truncated cone is threadedly connected to the first connecting end. The first connecting end located below the secondary truncated cone is connected to the injection-molded sealing cover 12. Four second wires 17 are embedded in the center of the injection-molded sealing cover 12.

[0094] The first lower end cover 1-2 includes a three-stage cone which is integrally connected, located at the upper end and in contact with the inner wall of the pneumatic impact kettle 1, and a four-stage cone which is located at the lower end and threadedly connected to the first connecting end; a first annular groove 1-5 is provided on the outer wall of the three-stage cone, and a first sealing member is provided in the first annular groove 1-5; a wire lead-out hole 1-6 runs through the first upper end cover 1-1; a first gas injection pipe hole 1-7 and a first threaded hole 1-4 which are connected from top to bottom are provided on the first lower end cover 1-2; a first temperature sensor interface 1-3 is provided on the side wall of the pneumatic impact kettle 1; a first temperature sensor 9 is provided in the first temperature sensor interface 1-3, the first temperature sensor 9 is connected to a data acquisition instrument, and the data acquisition instrument is connected to a computer.

[0095] A cylindrical fracturing tube 2 is arranged inside the pneumatic impact kettle 1; both upper and lower ends of the fracturing tube 2 are second connecting ends; threads are arranged on the second connecting end; the inner wall of the second connecting end forms a step with the inner wall of the fracturing tube 2; the inner diameter of the second connecting end is larger than the inner diameter of the middle part of the fracturing tube 2; the second upper end cover 2-1 and the second lower end cover 2-2 are respectively threadedly connected to the upper and lower ends of the fracturing tube 2; the second upper end cover 2-1 and the second lower end cover 2-2 are both stepped truncated cones, and the second upper end cover 2-1 includes a five-stage truncated cone which is integrally connected, located at the upper end and threadedly connected to the second connecting end, and a six-stage truncated cone which is located at the lower end and contacts the inner wall of the fracturing tube 2; The second lower end cover 2-2 includes a seven-stage truncated cone which is integrally connected, located at the upper end and in contact with the inner wall of the fracturing tube 2, and an eight-stage truncated cone which is located at the lower end and threadedly connected to the second connecting end; the outer walls of the six-stage truncated cone and the seven-stage truncated cone are respectively provided with a second annular groove 2-6 and a third annular groove 2-7, and the second annular groove 2-6 and the third annular groove 2-7 are respectively provided with a second sealing member and a third sealing member; the middle part of the outer wall of the tube body of the fracturing tube 2 is obtained by cutting to obtain a weak portion 2-8, and the wall thickness of the weak portion 2-8 is determined according to the test requirements; the second upper end cover 2 -1 has two symmetrical wire holes 2-10 for passing the first wire 13 at the lower part, and the two wire holes 2-10 extend upward to respectively form a second threaded hole 2-4 and a third threaded hole 2-5; a second temperature sensor interface 2-9 runs through the center of the second upper end cover 2-1; a second temperature sensor 10 is arranged in the second temperature sensor interface 2-9; a second gas injection pipe hole 2-11 is formed at the upper center of the second lower end cover 2-2, and a fourth threaded hole 2-3 is formed at the lower center of the second lower end cover 2-2, and the second gas injection pipe hole 2-11 and the fourth threaded hole 2-3 are connected.

[0096] An excitation member 3 is arranged inside the fracturing tube 2; the excitation member 3 is composed of an energy concentrator and an ignition head; the first wire 13 is connected to the ignition head and then passes through the second upper end cover 2-1 and is connected to the second wire 17 on the injection-molded sealing cover 12, and the second wire 17 is also connected to the lead of the second temperature sensor 10; the upper end of the second wire 17 passes through the wire lead-out hole 1-6 and is respectively connected to the excitation device and the data acquisition instrument.

[0097] The injection-molded sealing cover 12 is a stepped cone-shaped one, and includes a nine-step cone that is integrally connected, located at the upper end, and in contact with the first connecting end, and a ten-step cone that is located at the lower end and in contact with the inner wall of the pneumatic impact kettle 1. A fourth annular groove 18 is provided on the outer wall of the ten-step cone, and a fourth sealing member is provided in the fourth annular groove 18.

[0098] Sealing gaskets 16, 14, 14, 15 are arranged in the first threaded hole 1-4, the second threaded hole 2-4, the third threaded hole 2-5 and the fourth threaded hole 2-3. Sealing bolts 21, 19, 19, 20 are arranged at the outlets of the first threaded hole 1-4, the second threaded hole 2-4, the third threaded hole 2-5 and the fourth threaded hole 2-3; the first to fourth sealing members are all O-type sealing rings, the material of the O-type sealing rings is preferably rubber, and the size of the O-type sealing rings is respectively adapted to the size of the corresponding annular grooves; the sealing bolts 19, 20 and 21 are all provided with axial through holes with a diameter of 3 mm in the center for passing through the first gas injection pipe 4 and the single-core copper wire with an insulating layer, respectively, and the hole diameters are the same as the outer diameters of the two; the sealing gaskets 14, 15 and 16 are all made of polytetrafluoroethylene; the sealing gaskets are used in conjunction with the sealing bolts, and deform and fill the gaps under the extrusion of the sealing bolts to achieve a sealing effect.

[0099] The first gas injection pipe 4 passes through the first lower end cover 1-2 and the second lower end cover 2-2 in sequence and opens to the interior of the fracturing tube 2; one end of the three-way connector 5 is connected to the outer end of the first gas injection pipe 4 led out from the pneumatic impact kettle 1; one end is connected to the pressure sensor 7 through the second gas injection pipe; one end is connected to one port of the high-pressure needle valve 6 through the third gas injection pipe, and the other port of the high-pressure needle valve 6 is connected to the gas injection device through the fourth gas injection pipe.

[0100] An upper limiting ring 11 and a lower limiting ring 8 are arranged between the inner wall of the pneumatic impact kettle 1 and the outer wall of the fracturing tube 2, and a space for compacting powdered or granular coal rock samples is formed between the outer wall of the weak portion 2-8, the inner wall of the pneumatic impact kettle 1, the lower surface of the upper limiting ring 11 and the upper surface of the lower limiting ring 8.

[0101] The first wire 13 is preferably a single-core copper wire with an insulation layer; the second wire 17 is preferably an enameled copper wire; the gas injection device, the first temperature sensor 9, the second temperature sensor 10, the pressure sensor 7, the data acquisition instrument and the computer are all connected to the power supply.

[0102] The excitation device is a lithium high-energy initiator, which is rechargeable and has its own internal power supply.

[0103] The material of the upper restraint ring 11 and the lower restraint ring 8 is preferably iron.

[0104] The material of the pneumatic impact kettle 1 is stainless steel, with an outer diameter of 110mm, a wall thickness of 15mm and a height of 220mm; the wire lead-out hole 1-6 located in the center on the first upper end cover 1-1 has a diameter of 10mm; the first air injection pipe hole 1-7 in the upper center of the first lower end cover 1-2 has a diameter of 3mm, and a first threaded hole 1-4 is opened in the lower center. The first air injection pipe hole 1-7 and the first threaded hole 1-4 are connected and the axes coincide; the diameter of the non-threaded part of the first lower end cover 1-2 is 70mm, and the groove width of the first annular groove 1-5 thereon is 2.4mm and the groove depth is 1.8mm; a first temperature sensor interface 1-3 is arranged on the side wall of the pneumatic impact kettle 1, and the size is adapted to the first temperature sensor 9, which is specifically arranged at the center of the side wall of the pneumatic impact kettle 1 in the vertical direction.

[0105] The body of the fracturing tube 2 is made of a seamless steel tube with an outer diameter of 48 mm, a wall thickness of 3 mm, and a height of 100 mm, and the material is 20 steel; the outer wall of the fracturing tube 2 is cut to obtain a weak portion 2-8 with a wall thickness of 1.5 mm and a height of 5 mm, and the distance from the upper and lower ports is 25 mm; two wire holes 2-10 for passing a single-core copper wire with an insulating layer are symmetrically opened at the lower part of the second upper end cover 2-1, and the aperture of the wire hole 2-10 is the same as the diameter of the single-core copper wire and is 3 mm; two threaded holes are extended upward from the two wire holes 2-10, which are respectively connected and the axes coincide; the second A second temperature sensor interface 2-9 is arranged at the center of the upper end cover 2-1, and its size is adapted to the second temperature sensor 10; the diameter of the second gas injection pipe hole 2-11 at the upper center part of the second lower end cover 2-2 is 3mm, and a fourth threaded hole 2-3 is opened at the lower center part, and the second gas injection pipe hole 2-11 is connected to the fourth threaded hole 2-3 and their axes coincide; the diameter of the non-threaded part of the second upper end cover 2-1 and the second lower end cover 2-2 is the same as the inner diameter of the fracturing tube 2, which is 42mm, and the groove width of the second annular groove 2-6 and the third annular groove 2-7 thereon is 2.4mm, and the groove depth is 1.8mm.

[0106] The excitation component 3 is composed of an energy concentrator and an ignition head. The amount of the energy concentrator is 4g. The ignition head is buried in the center of the energy concentrator. The ignition head is connected to a single-core copper wire. The single-core copper wire continues upward to be connected to two of the second wires 17 pre-buried in the injection molding sealing cover 12 and is led out through the wire lead-out holes 1-6 of the pneumatic impact kettle 1, and is connected to an external excitation device to form an excitation system. The first gas injection pipe 4 is a stainless steel gas pipe with an outer diameter of 3mm, and the size is determined according to the test requirements. The first temperature sensor 9, the second temperature sensor 10 and the pressure sensor 7 are all high-precision, high-sampling rate sensors. The inner diameter of the upper limiting ring 11 and the lower limiting ring 8 are both 48.5mm, and the outer diameter is 79.5mm. The height of the upper limiting ring 11 is 45mm, and the height of the lower limiting ring 8 is 35mm. The injection-molded sealing cover 12 is made of hard, dense, and airtight injection-molded material, with four enameled copper wires embedded in the center; the diameter of the upper half of the injection-molded sealing cover 12 is the same as the outer diameter of the first upper end cover 1-1 of the pneumatic impact kettle 1, and there is no thread on it. The diameter of the lower half is 70mm, and a fourth annular groove 18 is opened on it, with a groove width and a groove depth of 2.4mm and 1.8mm respectively.

[0107] The threaded holes in this embodiment are used to set sealing gaskets and sealing bolts. The groove width and groove depth of the annular groove can also be determined according to the test requirements. The inner and outer diameters of the upper and lower sections of the limiting iron ring are the same, and its outer diameter is 0.5mm smaller than the inner diameter of the pneumatic impact kettle 1, and the inner diameter is 0.5mm larger than the outer diameter of the fracturing tube 2; the height of the upper section limiting ring 11 is the vertical distance between the top of the weak part 2-8 of the fracturing tube and the lower surface of the injection molding sealing cover 12, and the height of the lower section limiting ring 8 is the vertical distance between the bottom end of the weak part 2-8 of the fracturing tube and the upper surface of the first lower end cover 1-2; the limiting ring is used to limit the sample to the weak part 2-8 area of ​​the fracturing tube, thereby improving the fracturing impact effect and the target sample output rate.

[0108] Example 4

[0109] A method for using a transient high-pressure pneumatic impact destruction coal rock microstructure test device comprises the following steps:

[0110] Step 1: Tighten the first lower end cover 1-2 of the pneumatic impact kettle 1; fix the pneumatic impact kettle 1 vertically and keep it suspended up and down; fix the first temperature sensor 9 on the first temperature sensor interface 1-3;

[0111] Step 2: fix the second temperature sensor 10 to the second temperature sensor interface 2-9; take two first wires 13, pass them through the sealing gasket and the sealing bolts respectively and fix them on the second upper end cover 2-1 of the fracturing tube 2; trim the first wires 13 led out from the lower surface of the second upper end cover 2-1 to a suitable length and then connect them to the excitation member 3; trim the wires led out from the upper end of the second temperature sensor 10 to a suitable length; tighten the second upper end cover 2-1 to the upper pipe opening of the fracturing tube 2;

[0112] Step 3: Cut a section of the first gas injection pipe 4 of appropriate length, pass it through the sealing gasket and the sealing bolt and fix it on the second lower end cover 2-2; tighten the second lower end cover 2-2 to the lower pipe opening of the fracturing pipe 2;

[0113] Step 4: insert the fracturing tube 2 through the upper opening of the pneumatic impact kettle 1, and at the same time make the first gas injection tube 4 fixed in the second lower end cover 2-2 pass through the first gas injection tube hole 1-7 in the center of the first lower end cover 1-2 and lead out; keep the fracturing tube 2 at the bottom center of the pneumatic impact kettle 1; insert the lower limit ring 8; fix the first gas injection tube 4 to the first lower end cover 1-2 with a sealing gasket and a sealing bolt;

[0114] Step 5: Add the pre-prepared coal rock sample around the weak portion 2-8 of the fracturing tube 2 until the sample is flush with the top of the weak portion 2-8; insert the upper limit ring 11 and compact the sample;

[0115] Step 6: Connect the wires led out from the upper end of the second temperature sensor 10 to the four second wires 17 led out from the lower surface of the injection-molded sealing cover 12 according to the corresponding relationship; and put the injection-molded sealing cover 12 in;

[0116] Step 7: Tighten the first upper end cover 1-1, and at the same time, lead the second wire 17 extending from the upper surface of the injection-molded sealing cover 12 out from its wire lead-out hole 1-6 and connect it to an external wire; connect the external wire to the excitation device and the data acquisition instrument respectively;

[0117] Step 8: Connect the outer end of the second gas injection pipe 4 to the three-way joint 5; connect the pressure sensor 7 to the three-way joint 5 through the second gas injection pipe, and connect the pressure sensor 7 to the data acquisition instrument, and connect the data acquisition instrument to the computer; take a high-pressure needle valve 6, one end of which is connected to the three-way joint 5 through the third gas injection pipe, and the other end is connected to the gas injection device;

[0118] Step 9: Turn on the computer to monitor the pressure in the fracturing tube 2 in real time; open the high-pressure needle valve 6 to inject the test gas into the fracturing tube 2; close the high-pressure needle valve 6 after the gas pressure in the fracturing tube 2 reaches a predetermined value, and observe whether the pressure in the fracturing tube 2 remains stable; when the pressure in the fracturing tube 2 is stable, ignite the excitation member 3 through an excitation device located outside, and the fracturing tube 2 ruptures.

[0119] The test gas is preferably CO2.

[0120] In the description provided herein, a large number of specific details are described. However, it is understood that embodiments of the present invention can be practiced without these specific details. In some instances, well-known methods, structures and techniques are not shown in detail so as not to obscure the understanding of this description.

[0121] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by the terms "up", "down", "front", "back", "left", "right", etc. are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present invention.

[0122] Similarly, it should be understood that in order to streamline the present disclosure and aid in understanding one or more of the various inventive aspects, in the above description of exemplary embodiments of the present invention, various features of the present invention are sometimes grouped together into a single embodiment, figure, or description thereof. However, this disclosed method should not be interpreted as reflecting the intention that the claimed invention requires more features than those expressly recited in each claim. Rather, as reflected in the claims, inventive aspects lie in less than all of the features of the individual embodiments previously disclosed. Therefore, the claims that follow the detailed description are hereby expressly incorporated into the detailed description, with each claim itself serving as a separate embodiment of the present invention.

[0123] Although the present invention has been described according to a limited number of embodiments, it will be apparent to those skilled in the art, with the benefit of the above description, that other embodiments may be envisioned within the scope of the invention thus described. In addition, it should be noted that the language used in this specification is selected primarily for readability and teaching purposes, rather than for explaining or defining the subject matter of the present invention. Therefore, many modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the appended claims. The disclosure of the present invention is illustrative, not restrictive, with respect to the scope of the present invention, which is defined by the appended claims.

[0124] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A transient high-pressure pneumatic impact destruction of coal and rock microstructure test device, characterized in that: It comprises a cylindrical pneumatic impact kettle (1); a first upper end cover (1-1) and a first lower end cover (1-2) are movably connected to the upper and lower ends of the pneumatic impact kettle (1); a first temperature sensor (9) is arranged in the middle of the side wall of the pneumatic impact kettle (1); A fracturing tube (2) is arranged inside the pneumatic impact kettle (1); a second upper end cover (2-1) and a second lower end cover (2-2) are movably connected to the upper and lower ends of the fracturing tube (2) respectively; the second upper end cover (2-1) is connected to an excitation member (3) suspended in the fracturing tube (2) via a first wire (13); a second temperature sensor (10) is also arranged on the second upper end cover (2-1); the second lower end cover (2-2) is connected to the inner section of the first gas injection tube (4); the first gas injection tube (4) passes through the first lower end cover (1-2) outwards and is connected to a pressure sensor (7) and a high-pressure needle valve (6) via a three-way joint (5); the high-pressure needle valve (6) is connected to the gas injection device; A weak portion (2-8) is obtained by cutting in the middle of the outer wall of the tube body of the fracturing tube (2); an upper limiting ring (11) and a lower limiting ring (8) are arranged between the inner wall of the pneumatic impact kettle (1) and the outer wall of the fracturing tube (2); a space for compacting a powdered or granular coal rock sample is enclosed between the outer wall of the weak portion (2-8), the inner wall of the pneumatic impact kettle (1), the lower surface of the upper limiting ring (11) and the upper surface of the lower limiting ring (8); The first temperature sensor (9), the second temperature sensor (10) and the pressure sensor (7) are all connected to a data acquisition device, and the data acquisition device is connected to a computer; The first conducting wire (13) is connected to an excitation device.

2. The transient high-pressure pneumatic impact destruction of coal and rock microstructure test device according to claim 1 is characterized in that: The first conductor (13) comprises a single-core copper conductor with an insulation layer.

3. The transient high-pressure pneumatic impact destruction of coal and rock microstructure test device according to claim 1 is characterized in that: The gas injection device, the first temperature sensor (9), the second temperature sensor (10), the pressure sensor (7), the data acquisition instrument and the computer are all connected to a power source.

4. The transient high-pressure pneumatic impact destruction of coal and rock microstructure test device according to claim 1 is characterized in that: The pneumatic impact kettle (1) is made of high-pressure resistant stainless steel.

5. The transient high-pressure pneumatic impact destruction of coal and rock microstructure test device according to claim 1 is characterized in that: The pipe body of the fracturing pipe (2) is made from a seamless steel pipe.

6. The transient high-pressure pneumatic impact destruction of coal and rock microstructure test device according to claim 1 is characterized in that: The excitation element (3) is composed of an energy concentrator and an ignition head; the ignition head is buried in the center of the energy concentrator, and the ignition head is connected to the first wire (13).

7. The transient high-pressure pneumatic impact destruction of coal and rock microstructure test device according to claim 1 is characterized in that: The first gas injection pipe (4) is a stainless steel gas pipe; the upper limiting ring (11) and the lower limiting ring (8) are both made of iron.

8. A transient high-pressure pneumatic impact destruction of coal and rock microstructure test device, characterized in that: It comprises a cylindrical pneumatic impact kettle (1); The upper and lower ends of the pneumatic impact kettle (1) are both first connecting ends; The inner wall of the first connecting end and the inner wall of the pneumatic impact kettle (1) form a step shape; the inner diameter of the first connecting end is larger than the inner diameter of the middle part of the pneumatic impact kettle (1); The first connecting end is provided with a thread; The first upper end cover (1-1) and the first lower end cover (1-2) are respectively threadedly connected to the upper and lower ends of the pneumatic impact kettle (1); The first upper end cover (1-1) and the first lower end cover (1-2) are both stepped truncated cone-shaped, the first upper end cover (1-1) comprising a first truncated cone located at the upper end and a second truncated cone located at the lower end, which are integrally connected; the diameter of the first truncated cone is smaller than the diameter of the second truncated cone, the second truncated cone is threadedly connected to the first connecting end, and the first connecting end located below the second truncated cone is connected to the injection-molded sealing cover (12); Four second wires (17) are embedded through the center of the injection-molded sealing cover (12); The first lower end cover (1-2) comprises a three-stage truncated cone located at the upper end and in contact with the inner wall of the pneumatic impact kettle (1) and a four-stage truncated cone located at the lower end and threadedly connected to the first connecting end; A first annular groove (1-5) is provided on the outer wall of the three-stage truncated cone, and a first sealing member is provided in the first annular groove (1-5); The first upper end cover (1-1) is penetrated by a wire lead-out hole (1-6); The first lower end cover (1-2) is provided with a first gas injection pipe hole (1-7) and a first threaded hole (1-4) which are connected from top to bottom; The side wall of the pneumatic impact kettle (1) is provided with a first temperature sensor interface (1-3); A first temperature sensor (9) is arranged in the first temperature sensor interface (1-3), the first temperature sensor (9) is connected to a data acquisition device, and the data acquisition device is connected to a computer; A cylindrical fracturing tube (2) is arranged inside the pneumatic impact kettle (1); The upper and lower ends of the fracturing tube (2) are both second connecting ends; The second connecting end is provided with a thread; The inner wall of the second connecting end and the inner wall of the fracturing tube (2) form a step-like shape; the inner diameter of the second connecting end is larger than the inner diameter of the middle part of the fracturing tube (2); The second upper end cover (2-1) and the second lower end cover (2-2) are respectively threadedly connected to the upper and lower ends of the fracturing tube (2); The second upper end cover (2-1) and the second lower end cover (2-2) are both stepped truncated cones, the second upper end cover (2-1) comprising a five-step truncated cone integrally connected at the upper end and threadedly connected to the second connecting end, and a six-step truncated cone at the lower end in contact with the inner wall of the fracturing tube (2); The second lower end cover (2-2) comprises a seven-stage frustum located at the upper end and in contact with the inner wall of the fracturing tube (2) and an eight-stage frustum located at the lower end and threadedly connected to the second connecting end; A second annular groove (2-6) and a third annular groove (2-7) are respectively provided on the outer walls of the six-stage truncated cone and the seven-stage truncated cone, and a second sealing member and a third sealing member are respectively provided in the second annular groove (2-6) and the third annular groove (2-7); The middle part of the outer wall of the fracture-causing tube (2) is cut to obtain a weak part (2-8); The lower part of the second upper end cover (2-1) is symmetrically provided with two wire holes (2-10) for passing the first wire (13), and the two wire holes (2-10) are respectively extended upward to form a second threaded hole (2-4) and a third threaded hole (2-5); A second temperature sensor interface (2-9) runs through the center of the second upper end cover (2-1); A second temperature sensor (10) is arranged in the second temperature sensor interface (2-9); A second gas injection pipe hole (2-11) is opened at the upper center of the second lower end cover (2-2), a fourth threaded hole (2-3) is opened at the lower center of the second lower end cover (2-2), and the second gas injection pipe hole (2-11) and the fourth threaded hole (2-3) are connected; An excitation member (3) is arranged inside the fracturing tube (2); The ignition element (3) is composed of an energy concentrator and an ignition head; The first wire (13) is connected to the ignition head and then passes through the second upper end cover (2-1) to be connected to the second wire (17) on the injection-molded sealing cover (12); the second wire (17) is also connected to the lead of the second temperature sensor (10); the upper end of the second wire (17) passes through the wire lead-out hole (1-6) and is respectively connected to the excitation device and the data acquisition instrument; The injection-molded sealing cover (12) is of a stepped truncated cone type, comprising a nine-step truncated cone located at the upper end and in contact with the first connecting end, and a ten-step truncated cone located at the lower end and in contact with the inner wall of the pneumatic impact kettle (1), wherein a fourth annular groove (18) is provided on the outer wall of the ten-step truncated cone, and a fourth sealing member is provided in the fourth annular groove (18); Sealing gaskets are provided in the first threaded hole (1-4), the second threaded hole (2-4), the third threaded hole (2-5) and the fourth threaded hole (2-3); Sealing bolts are provided at the outlets of the first threaded hole (1-4), the second threaded hole (2-4), the third threaded hole (2-5) and the fourth threaded hole (2-3); The sealing gasket and the sealing bolt are both provided with an axial through hole; A first gas injection pipe (4) sequentially penetrates the first lower end cover (1-2) and the second lower end cover (2-2) and opens into the interior of the fracturing tube (2); One end of the three-way connector (5) is connected to the outer end of the first gas injection pipe (4) leading from the pneumatic impact kettle (1); one end is connected to the pressure sensor (7) through the second gas injection pipe; one end is connected to one end of the high-pressure needle valve (6) through the third gas injection pipe, and the other end of the high-pressure needle valve (6) is connected to the gas injection device through the fourth gas injection pipe; An upper limiting ring (11) and a lower limiting ring (8) are arranged between the inner wall of the pneumatic impact kettle (1) and the outer wall of the fracturing tube (2); a space for compacting powdered or granular coal rock samples is formed between the outer wall of the weak portion (2-8), the inner wall of the pneumatic impact kettle (1), the lower surface of the upper limiting ring (11) and the upper surface of the lower limiting ring (8).

9. The transient high-pressure pneumatic impact destruction of coal and rock microstructure test device according to claim 8, characterized in that: The first conductor (13) comprises a single-core copper conductor with an insulation layer; the second conductor (17) comprises an enameled copper conductor; the gas injection device, the first temperature sensor (9), the second temperature sensor (10), the pressure sensor (7), the data acquisition instrument and the computer are all connected to a power supply; the upper limiting ring (11) and the lower limiting ring (8) are both made of iron; the first sealing member, the second sealing member, the third sealing member and the fourth sealing member are all O-rings.

10. The method for using the transient high-pressure pneumatic impact destruction coal rock microstructure test device according to claim 8 or 9, characterized in that: The steps include: Step 1: Tighten the first lower end cover (1-2) of the pneumatic impact kettle (1); fix the pneumatic impact kettle (1) vertically and keep it suspended in the air; fix the first temperature sensor (9) to the first temperature sensor interface (1-3); Step 2: fix the second temperature sensor (10) to the second temperature sensor interface (2-9); take two first wires (13), pass them through the sealing gasket and the sealing bolt respectively, and fix them to the wire hole (2-10) of the second upper end cover (2-1) of the fracturing tube (2); connect the first wire (13) led out from the lower surface of the second upper end cover (2-1) to the excitation member (3); lead the two lead wires of the second temperature sensor (10) upward; and tighten the second upper end cover (2-1) to the upper tube opening of the fracturing tube (2); Step 3: Cut a section of the first gas injection pipe (4), pass it through a sealing gasket and a sealing bolt, and fix it on the second lower end cover (2-2); tighten the second lower end cover (2-2) to the lower pipe opening of the fracturing pipe (2); Step 4: insert the fracturing tube (2) through the upper opening of the pneumatic impact kettle (1), and at the same time allow the first gas injection tube (4) fixed in the second lower end cover (2-2) to pass through the first gas injection tube hole (1-7) in the center of the first lower end cover (1-2) and be led out; keep the fracturing tube (2) at the bottom center of the pneumatic impact kettle (1); insert the lower limit ring (8); and fix the first gas injection tube (4) to the first lower end cover (1-2) using a sealing gasket and a sealing bolt; Step 5: Add the pre-prepared coal and rock samples around the weak part (2-8) of the fracturing tube (2) until the samples are flush with the top of the weak part (2-8); insert the upper limiting ring (11) and compact the samples; Step 6: Connect the wires led out from the upper end of the second temperature sensor (10) to the four second wires (17) led out from the lower surface of the injection-molded sealing cover (12) according to the corresponding relationship; and insert the injection-molded sealing cover (12); Step 7: Tighten the first upper end cover (1-1), and at the same time, lead out the second wire (17) extending from the upper surface of the injection-molded sealing cover (12) from its wire lead-out hole (1-6) and connect it to an external wire; connect the external wire to the excitation device and the data acquisition instrument respectively; Step 8: Connect the outer end of the second gas injection pipe (4) to the three-way connector (5); connect the pressure sensor (7) to the three-way connector (5) through the second gas injection pipe, and connect the pressure sensor (7) to the data acquisition instrument, and connect the data acquisition instrument to the computer; take a high-pressure needle valve (6), one end of which is connected to the three-way connector (5) through the third gas injection pipe, and the other end is connected to the gas injection device; Step 9: Turn on the computer to monitor the pressure in the fracturing tube (2) in real time; open the high-pressure needle valve (6) to inject the test gas into the fracturing tube (2); close the high-pressure needle valve (6) after the gas pressure in the fracturing tube (2) reaches a predetermined value, and observe whether the pressure in the fracturing tube (2) remains stable; when the pressure in the fracturing tube (2) remains stable, ignite the ignition member (3) through an external ignition device, and rupture the fracturing tube (2).

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