An air-reverse circulation drilling slag guide device for permafrost

Abstract

This invention discloses an air-assisted reverse circulation drilling cuttings guiding device for permafrost, relating to the field of drilling equipment technology. It includes a double-walled drill rod and an inner drill rod. An outer drill bit is installed at the end of the double-walled drill rod, with a cuttings guiding channel formed by the gap between the two. The inner drill rod is rotatably positioned within the cuttings guiding channel, with helical blades on the outside and an inner drill bit at the end. An outer annular gap communicating with the cuttings guiding channel is provided inside the double-walled drill rod, and a sampling chamber is located inside the outer drill bit. During operation, the double-walled drill rod drives the outer drill bit to open and enlarge the hole, while the inner drill rod drives the inner drill bit to break the rock mass. The elastic body between the inner drill bit and the inner drill rod provides axial preload to enhance the rock-breaking effect. A mixed liquid is injected into the bottom of the hole through a liquid passage and a liquid storage chamber via a jet hole to prevent rock dust from freezing. High-pressure air enters the cuttings guiding channel through the outer annular gap, and combined with the helical blades, it achieves dual-drive upward return of rock cuttings, avoiding deposition and drill bit jamming. Simultaneously, precise sampling is achieved through the sampling chamber.

Description

Technical Field

[0001] This invention relates to the field of drilling technology, and more specifically to an air reverse circulation drilling slag guide device for permafrost. Background Technology

[0002] Air reverse circulation drilling utilizes compressed air to descend through the annulus of the double-walled drill pipe, breaking the rock and carrying the rock cuttings back to the surface rapidly through the central inner tube, achieving continuous sampling and efficient drilling.

[0003] When conventional air reverse circulation drilling equipment drills into deeper sections of the hole, the higher pressure inside the hole causes the rock cuttings to be carried a longer distance, requiring greater circulating air pressure to successfully bring them out of the hole. At the same time, especially when drilling through permafrost, the low temperature of the permafrost can easily freeze the rock powder, causing blockage of the reverse circulation system and stopping the machine. When the drill bit is drilling through permafrost, the drill bit is cylindrical, and the drill cuttings left inside the drill bit will be in blocky form. These blocky forms are not easy to crush during the transport process and are more likely to cause blockages during the upward transport.

[0004] Therefore, the present invention provides a drilling device for high-altitude permafrost to solve the above-mentioned problems. Summary of the Invention

[0005] To address the aforementioned technical shortcomings, the present invention aims to provide an air reverse circulation drilling cuttings guiding device for permafrost. This device incorporates an inner drill rod within the double-walled drill rod and a spiral ascending channel within the cuttings guiding channel. Through the coordinated operation of the inner and outer drill bits, the overall rock-breaking efficiency is improved.

[0006] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: The present invention provides an air reverse circulation drilling slag guide device for permafrost, comprising: A double-walled drill rod, wherein an external drill bit is installed at the end of the double-walled drill rod, and the gap between the double-walled drill rod and the external drill bit forms a slag guiding channel; An inner drill rod is rotatably installed inside the slag guide channel. The outer side of the inner drill rod is provided with helical blades, which form a helical channel inside the slag guide channel. An inner drill bit is installed at the end of the inner drill rod. The double-walled drill pipe has an outer annular gap inside, which is connected to the slag guide channel. The connection between the outer annular gap and the slag guide channel is located outside the inner drill bit. The airflow direction is from the outer annular gap to the slag guide channel, and the air rises along the spiral channel inside the slag guide channel.

[0007] Preferably, the inner drill bit is fitted onto the inner drill rod, the inner drill bit is provided with a jetting hole, the inner drill rod is provided with a fluid passage hole, one end of the fluid passage hole is connected to the jetting hole, and the other end passes through the central hole inside the inner drill rod and is connected to the fluid supply unit.

[0008] Preferably, the inner drill bit and the inner drill rod are axially slidably connected, an elastic body is installed at the connection between the inner drill bit and the inner drill rod, the inner drill bit has a liquid storage chamber inside, the liquid storage chamber is connected to the liquid passage hole, and a one-way valve is installed inside the liquid passage hole.

[0009] Preferably, the internal drill bit includes a drill body, the drill body has a cutting edge on its outside, the cutting edge is spiral, and a transverse cutting edge is installed at the center of the end of the drill body.

[0010] Preferably, a sampling chamber is provided at the end of the slag guide channel, and the sampling chamber is located inside the external drill bit.

[0011] Preferably, the slag guiding device further includes: A mobile body is mounted on a drilling equipment, and both the double-walled drill rod and the inner drill rod are rotatably mounted on the mobile body. An air supply system is provided, including a sleeve that is fitted onto a double-walled drill rod. The sleeve has an annular hole inside that communicates with the outer ring gap. An air supply pipe is installed on the sleeve and is connected to an air compressor outside the slag guiding device.

[0012] Preferably, an end sleeve is fixed inside the movable body, and the end of the double-walled drill rod is rotatably installed inside the end sleeve. The end sleeve is provided with a slag suction port, the opening of which is connected to the slag guiding channel. The slag suction port is connected to a slag suction machine outside the slag guiding device through a pipe.

[0013] Preferably, the end of the inner drill rod away from the inner drill bit extends through the end sleeve into the interior of the moving body, and the end of the inner drill rod is connected to the liquid supply pipe, with the liquid passage hole communicating with the liquid supply pipe.

[0014] Preferably, the external drill bit includes a cylinder, on the outer wall of which multiple vertical plates are connected, with gaps between adjacent vertical plates, and multiple cutting teeth at the end of the cylinder.

[0015] Preferably, the innermost ends of the plurality of cutting teeth form an inner circle, the diameter of which is smaller than the inner diameter of the cylinder.

[0016] The beneficial effects of this invention are as follows: The double-walled drill rod of this drilling and slag guiding device drives the external drill bit at the end to achieve rotary cutting and hole opening and enlargement; the internal drill rod drives the internal drill bit to perform central crushing and refinement of the rock mass. The internal and external drill bits work together to improve the overall rock breaking efficiency.

[0017] When the inner drill bit contacts the rock formation and is compressed, the elastic body is compressed. Under the action of elastic restoring force, the inner drill rod continuously applies axial pre-tightening pressure to the inner drill bit, so that the drill bit always fits the rock formation, improving the cutting and impact crushing effect.

[0018] The mixture is injected into the bottom of the hole through the internal fluid passage and storage chamber of the inner drill rod and then through the injection hole of the inner drill bit. The physicochemical dispersion effect of the thawing agent is used to inhibit the freezing of rock powder, avoid ice blockage of circulation channels during construction in permafrost layers, and ensure smooth upward return of rock cuttings.

[0019] The inner drill pipe is equipped with helical blades on the outside, forming a spiral upward channel in the cuttings guide channel. When the inner drill pipe rotates, the helical blades rotate synchronously, applying an upward axial thrust to the rock cuttings in the cuttings guide channel. After the rock cuttings are crushed and refined by the inner and outer drill bits, they are quickly and stably transported from bottom to top of the device along the cuttings guide channel under the dual action of air reverse circulation buoyancy and forced pushing by the helical blades, avoiding rock cuttings deposition and stuck drill bits. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0021] Figure 1 This is an internal view of a double-walled drill rod and an external drill bit.

[0022] Figure 2 This is a schematic diagram of a double-walled drill rod and an external drill bit.

[0023] Figure 3 for Figure 1 Enlarged view of point A in the image.

[0024] Figure 4 This is a schematic diagram of the internal drill pipe and internal drill bit.

[0025] Figure 5 This is an internal view of the internal drill pipe and internal drill bit.

[0026] Figure 6 This is an internal sectional view showing the connection between the moving body, the double-walled drill pipe, and the inner drill pipe.

[0027] Figure 7 for Figure 6 A cross-sectional view along the BB direction.

[0028] Figure 8 for Figure 6 A cross-sectional view along the CC direction.

[0029] Figure 9 This is a schematic diagram of the drilling slag guide device.

[0030] Explanation of reference numerals in the attached figures: 1. Double-walled drill rod; 2. Slag guide channel; 3. Outer annular gap; 4. External drill bit; 401. Cylinder; 402. Vertical plate; 403. Cutting teeth; 5. Inner drill rod; 6. Inner drill bit; 601. Drill body; 602. Cutting edge; 603. Horizontal cutting edge; 7. Moving body; 8. Sleeve; 9. Gas supply pipe; 10. Sampling chamber; 11. Helical blade; 12. First gear; 13. Second gear; 14. Third gear; 15. End sleeve; 16. Support; 17. Liquid storage chamber; 18. Elastomer. Detailed Implementation

[0031] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0032] Example 1 like Figures 1 to 4 As shown, the present invention provides an air reverse circulation drilling slag guide device for permafrost, comprising a double-walled drill rod 1 and an inner drill rod 5.

[0033] The double-walled drill rod 1 is rotatably mounted on the drilling equipment. An external drill bit 4 is installed at the end of the double-walled drill rod 1. The gap between the double-walled drill rod 1 and the external drill bit 4 forms the cuttings guide channel 2. The external drill bit 4 is installed at the end of the double-walled drill rod 1 and can first contact the rock strata to open the hole. The rock cuttings are transported to the ground through the cuttings guide channel 2 under the action of airflow.

[0034] The inner drill rod 5 is rotatably installed inside the cuttings guide channel 2. The outer side of the inner drill rod 5 is provided with a spiral blade 11, which forms a spiral channel inside the cuttings guide channel 2. The end of the inner drill rod 5 is equipped with an inner drill bit 6. The spiral blade 11 is located between the inner drill rod 5 and the double-walled drill rod 1 to form a spiral upward channel. The outer diameter of the spiral blade 11 is slightly smaller than the inner diameter of the cuttings guide channel 2, leaving a flow gap to prevent jamming. At the same time, when the spiral blade 11 rotates, it can apply an upward thrust to the rock cuttings, further improving the upward effect of the rock cuttings. The inner drill bit 6 can break the rock strata, crushing and refining large rock masses, making them easier to discharge upward through the spiral channel.

[0035] The double-walled drill pipe 1 has an outer annular gap 3 inside, which is connected to the cuttings guide channel 2. The connection between the outer annular gap 3 and the cuttings guide channel 2 is located outside the inner drill bit 6. The airflow direction is from the outer annular gap 3 to the cuttings guide channel 2. The outer annular gap 3 forms a high-pressure air flow channel, and its upper end is connected to the air compressor. After the air compressor is started, the high-pressure air enters the cuttings guide channel 2 through the outer annular gap 3 and flows upward along the cuttings guide channel 2. The rock cuttings move upward under the entrainment of the airflow. At the same time, the spiral blades 11 on the outer side of the inner drill pipe 5 rotate synchronously, pushing the rock cuttings in the cuttings guide channel 2 upward. Driven by both airflow lifting and spiral blade 11 pushing, the rock cuttings in the cuttings guide channel 2 can be smoothly transported to the surface. The end of the cuttings guide channel 2 is equipped with a sampling chamber 10, which is located inside the outer hole drill bit 4. The sampling chamber 10 is located inside the end of the outer hole drill bit 4 and is used to hold the rock strata sample that enters first. At the same time, the rock strata that the drilling device first contacts are collected inside the sampling chamber 10. When taking samples, it is only necessary to bring the drilling device to the surface.

[0036] The external drill bit 4 includes a cylinder 401, with multiple vertical plates 402 connected to the outer wall of the cylinder 401. There is a gap between adjacent vertical plates 402. The end of the cylinder 401 has multiple cutting teeth 403. The vertical plates 402 are distributed on the outside of the cylinder 401 and can correct the hole wall formed by drilling. The vertical plates 402 are fixed to the cylinder 401 by bolts, which facilitates the replacement of the vertical plates 402.

[0037] The innermost ends of multiple cutting teeth 403 form an inner circle, the diameter of which is smaller than the inner diameter of the cylinder 401. The multiple cutting teeth 403 are arranged circumferentially at the bottom of the cylinder 401, with a pre-reserved gap between adjacent cutting teeth 403, and the outer diameter of the cutting teeth 403 is smaller than the inner diameter of the cylinder 401. The bottom of the outer hole drill bit 4 has a tapering structure. During drilling and sampling, the sample enters the cylinder 401. After the outer hole drill bit 4 stops rotating, the inwardly tapering cutting teeth 403 can clamp the sample in the sampling chamber 10, preventing it from falling out, thereby achieving accurate sampling.

[0038] Example 2 like Figure 4 and Figure 5 As shown, based on Embodiment 1, this embodiment provides the structure of the internal drill bit 6 and the driving method of the internal drill bit 6, as detailed below: The inner drill rod 5 has a central hole inside, and the inner drill bit 6 is fitted onto the inner drill rod 5. A guide groove is provided at the connection between the inner drill bit 6 and the inner drill rod 5 to ensure that the inner drill bit 6 can only move along the axial direction of the inner drill rod 5. The inner drill bit 6 and the inner drill rod 5 are connected by the guide groove, which can be opened on the outer surface of the inner drill rod 5. The inner drill bit 6 is provided with a sliding strip that matches the guide groove, which restricts the circumferential rotation of the inner drill bit 6 but allows its axial sliding. The inner drill bit 6 has a jetting hole, and the inner drill rod 5 has a liquid passage hole inside. One end of the liquid passage hole is connected to the jetting hole, and the other end passes through the central hole inside the inner drill rod 5 and is connected to the liquid supply unit. The liquid supply unit injects a mixture of defrosting agent and foaming agent into the borehole. The physicochemical dispersion effect of the defrosting agent is used to prevent rock powder from freezing and clogging, ensuring that rock cuttings can be returned normally. This construction method can effectively solve the problem of circulation system blockage caused by freezing during construction in permafrost layers.

[0039] The inner drill bit 6 and the inner drill rod 5 are axially slidably connected. An elastic body 18 is installed at the connection between the inner drill bit 6 and the inner drill rod 5. The inner drill bit 6 and the inner drill rod 5 are circumferentially limited and cannot rotate. The inner drill bit 6 can only slide along the axial direction of the inner drill rod 5. Under normal conditions, the elastic body 18 is in the extended state. When the inner drill bit 6 contacts the rock formation and is under pressure, the elastic body 18 is compressed. Under the reset action of the elastic body 18, the inner drill rod 5 continuously applies axial pressure to the inner drill bit 6, thereby improving the drilling and breaking effect. The inner drill bit 6 has a liquid storage chamber 17 inside, which is connected to the liquid passage hole. A one-way valve is installed at the connection between the liquid passage hole and the liquid storage chamber 17. The mixture of defreezing agent and foaming agent is injected from the liquid passage hole into the injection hole and then into the interior of the borehole. The one-way valve ensures that the liquid can only flow in one direction.

[0040] The internal drill bit 6 includes a drill body 601. The drill body 601 has a cutting edge 602 on its outside. The cutting edge 602 is spiral. A transverse cutting edge 603 is installed at the center of the end of the drill body 601. The spiral cutting edge 602 can guide and smooth the hole wall. The transverse cutting edge 603 can center and cut into the hole, ensuring that the position of the drill hole will not shift.

[0041] The injection hole is equipped with a one-way valve. The flow direction of the one-way valve is from the inside to the outside. The one-way valve installed inside the injection hole can prevent mud and sand from entering the injection hole in the opposite direction during the drilling process.

[0042] Example 3 like Figures 6-9 As shown, based on Embodiment 1 and Embodiment 2, this embodiment provides a driving method for the double-walled drill pipe 1 and the inner drill pipe 5, as detailed below: The slag guiding device also includes a moving body 7, an air supply system, and a slag suction structure: The moving body 7 is mounted on the support 16 of the drilling equipment and is driven up and down by a motor and a screw. The driving method of the moving body 7 is a common component in the prior art and is not an innovation of this invention, so this invention will not elaborate on it. The double-wall drill rod 1 and the inner drill rod 5 are both rotatably mounted on the moving body 7. A first gear 12 is rotatably mounted inside the moving body 7. The outer wall of the double-wall drill rod 1 is provided with tooth segments that mesh with the first gear 12. A first motor is fixed on the moving body 7. The first motor can drive the first gear 12 to rotate. The first gear 12 drives the double-wall drill rod 1 to rotate through meshing transmission. The air supply system includes a sleeve 8, which is fitted onto the double-walled drill rod 1. The sleeve 8 has an annular hole inside, which communicates with the outer annular gap 3. An air supply pipe 9 is installed on the sleeve 8, which is connected to an air compressor outside the slag guiding device. The sleeve 8 is fixedly installed on the moving body 7. The inner wall of the double-walled drill rod 1 has multiple connecting holes along the circumference that communicate with the annular hole. The annular hole communicates with the outer annular gap 3 through the connecting holes, and compressed air can then be introduced into the outer annular gap 3 through the air supply system.

[0043] The moving body 7 has an end sleeve 15 fixed inside. The end of the double-walled drill rod 1 is rotatably installed inside the end sleeve 15. The end sleeve 15 is provided with a slag suction port. The opening of the slag suction port is connected to the slag guiding channel 2. The slag suction port is connected to the slag suction machine outside the slag guiding device through a pipe. The slag guiding channel 2 transports the rock cuttings from bottom to top. After the rock cuttings are transported to the top, they are discharged from the slag guiding device through the slag suction port, realizing the external discharge of rock cuttings. The slag suction port adopts an annular opening structure, which facilitates the entry of rock cuttings into the slag suction port from multiple angles.

[0044] The end of the inner drill rod 5 away from the inner drill bit 6 extends through the end sleeve 15 into the interior of the moving body 7, and the end of the inner drill rod 5 is connected to the liquid supply pipe. The liquid passage hole is connected to the liquid supply pipe, and the liquid supply pipe and the inner drill rod 5 are connected by a rotary joint, which can ensure the normal rotation of the inner drill rod 5 and enable the liquid supply pipe to continuously supply liquid into the liquid passage hole. A second gear 13 is fixedly installed in the section of the inner drill rod 5 located inside the moving body 7. A third gear 14 that meshes with the second gear 13 is rotatably installed inside the moving body 7. A second motor for driving the rotation of the third gear 14 is fixed on the moving body 7. The second motor can be a low-speed motor. Before the inner drill bit 6 contacts the rock layer, the outer hole drill bit 4 will pre-crush the rock layer in advance, so that the inner drill bit 6 only needs to complete the crushing operation of the internal rock layer at a low speed. At the same time, the spiral blade 11 rotates with the inner drill rod at a low speed, which can effectively reduce the damage to the spiral structure of the slag guide channel 2 and ensure the normal operation of the slag guide channel.

[0045] Working principle: After the drilling slag guide device is started, the screw is driven by the motor to rotate, which drives the moving body 7 to feed downward along the support 16 of the drilling equipment, and drives the entire drilling tool to feed downward, so that the outer drill bit 4 and the inner drill bit 6 contact the rock formation to carry out drilling operations.

[0046] The first motor starts, driving the first gear 12 to rotate. Through gear meshing, the double-walled drill rod 1 rotates, which in turn drives the outer drill bit 4 at its end to rotate, achieving hole opening and rock cutting. Simultaneously, the second motor starts, driving the third gear 14 to mesh with the second gear 13, causing the inner drill rod 5 to rotate synchronously. The inner drill rod 5 drives the inner drill bit 6 to perform central crushing of the rock strata, refining large rock blocks for easier subsequent removal. The inner drill rod 5 and the inner drill bit 6 are circumferentially limited by guide grooves, allowing only axial relative sliding. Under normal conditions, the elastic body 18 is in an extended state. When the inner drill bit 6 contacts the rock strata and is subjected to pressure, the elastic body 18 is compressed. Under elastic reset, the inner drill rod 5 continuously applies axial pressure to the inner drill bit 6, improving drilling and crushing effects. The spiral cutting edge 602 on the outside of the inner drill bit 6 serves as a guide for hole finishing, and the transverse cutting edge 603 at the end achieves drilling centering, ensuring accurate borehole positioning.

[0047] The external air supply system introduces high-pressure air into the annular hole through the air supply pipe 9 on the sleeve 8. The annular hole is connected to the outer ring gap 3 through multiple connecting holes on the inner wall of the double-wall drill rod 1. The high-pressure air flows downward along the outer ring gap 3 to the bottom of the hole and enters the cuttings guide channel 2 from the outside of the inner drill bit 6, forming a reverse circulation airflow from bottom to top, which generates an upward entrainment and lifting force on the rock cuttings.

[0048] The liquid supply unit delivers a mixture of defrosting agent and foaming agent via a supply pipe connected to the inner drill rod 5 through a rotary joint, ensuring continuous liquid supply while allowing the inner drill rod 5 to rotate normally. The mixture flows sequentially through the liquid passage hole inside the inner drill rod 5 and the liquid storage chamber 17 inside the inner drill bit 6, finally being injected into the bottom of the borehole through the injection hole. Both the liquid passage hole and the injection hole are equipped with one-way valves, ensuring that the liquid can only flow out from the inside to the outside, while preventing mud and sand from flowing back and clogging the channels. The mixture utilizes the physicochemical dispersion effect of the defrosting agent to inhibit rock powder freezing, preventing blockage of the circulation channels during permafrost construction and ensuring the normal upward return of rock cuttings.

[0049] The spiral blades 11 on the outside of the inner drill rod 5 rotate synchronously with the inner drill rod 5, forming a spiral upward channel within the cuttings guide channel 2, applying an upward pushing force to the rock cuttings. Under the dual action of being carried by the reverse airflow and forcibly pushed by the spiral blades 11, the rock cuttings are rapidly transported from bottom to top along the cuttings guide channel 2 to the top of the device. The annular suction port at the top of the cuttings guide channel 2 is connected to an external cuttings suction machine. The annular structure facilitates the entry of rock cuttings from multiple angles. The rock cuttings are extracted from the cuttings guide device through the suction port, completing continuous cuttings discharge.

[0050] During drilling, the vertical plate 402 on the outer side of the outer borehole drill bit 4 cylinder 401 rotates synchronously with the drill bit to trim the borehole wall and ensure its regularity. The sample that first contacts the rock strata enters the sampling chamber 10 inside the outer borehole drill bit 4. The bottom of the outer borehole drill bit 4 has a tapering structure. After rotation stops, the inwardly retracting cutting teeth 403 can hold the sample in the sampling chamber 10 to prevent it from falling out. After drilling is completed, the moving body 7 lifts the entire drill string, bringing the drill string and sampling chamber 10 to the surface, where rock samples can be retrieved, completing the entire process of drilling, cuttings removal, and sampling.

[0051] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, this invention also intends to include these modifications and variations.

Claims

1. An air reverse circulation drilling slag guide device for permafrost, characterized in that, include: A double-walled drill rod (1) is provided with an external drill bit (4) installed at its end. The gap between the double-walled drill rod (1) and the external drill bit (4) forms a slag guide channel (2). The inner drill rod (5) is rotatably installed inside the slag guide channel (2). The outer side of the inner drill rod (5) is provided with a spiral blade (11). The spiral blade (11) forms a spiral channel inside the slag guide channel (2). The end of the inner drill rod (5) is equipped with an inner drill bit (6). The double-walled drill pipe (1) has an outer ring gap (3) inside, which is connected to the slag guide channel (2). The connection position between the outer ring gap (3) and the slag guide channel (2) is located outside the inner drill bit (6). The air flow direction is from the outer ring gap (3) to the slag guide channel (2), and the air rises along the spiral channel inside the slag guide channel (2).

2. The air reverse circulation drilling slag guide device for permafrost as described in claim 1, characterized in that, The inner drill bit (6) is fitted onto the inner drill rod (5). The inner drill bit (6) has a jet hole, and the inner drill rod (5) has a liquid passage hole inside. One end of the liquid passage hole is connected to the jet hole, and the other end passes through the central hole inside the inner drill rod (5) and is connected to the liquid supply unit outside the slag guiding device.

3. The air reverse circulation drilling slag guide device for permafrost as described in claim 2, characterized in that, The inner drill bit (6) and the inner drill rod (5) are axially slidably connected. An elastic body (18) is installed at the connection between the inner drill bit (6) and the inner drill rod (5). The inner drill bit (6) has a liquid storage chamber (17) inside, which is connected to the liquid passage hole.

4. The air reverse circulation drilling slag guide device for permafrost as described in claim 2, characterized in that, The internal drill bit (6) includes a drill body (601), and the drill body (601) is provided with a cutting edge (602) on the outside. The cutting edge (602) is spiral in shape, and a transverse cutting edge (603) is installed at the center of the end of the drill body (601).

5. The air reverse circulation drilling slag guide device for permafrost as described in claim 1, characterized in that, The end of the slag guide channel (2) is provided with a sampling chamber (10), which is located inside the external drill bit (4).

6. The air reverse circulation drilling slag guide device for permafrost as described in claim 2, characterized in that, The slag guiding device also includes: The mobile body (7) is installed on the drilling equipment, and the double-walled drill rod (1) and the inner drill rod (5) are rotatably installed on the mobile body (7); The gas supply system includes a sleeve (8) which is fitted onto the double-walled drill rod (1). The sleeve (8) has an annular hole inside, which is connected to the outer ring gap (3). A gas supply pipe (9) is installed on the sleeve (8), and the gas supply pipe (9) is connected to an air compressor outside the slag guiding device.

7. The air reverse circulation drilling cuttings guiding device for permafrost as described in claim 6, characterized in that, The moving body (7) has an end sleeve (15) fixed inside. The end of the double-walled drill rod (1) is rotatably installed inside the end sleeve (15). The end sleeve (15) has a slag suction port inside. The opening of the slag suction port is connected to the slag guiding channel (2).

8. The air reverse circulation drilling slag guide device for permafrost as described in claim 7, characterized in that, The end of the inner drill rod (5) away from the inner drill bit (6) extends through the end sleeve (15) into the interior of the moving body (7), and the end of the inner drill rod (5) is connected to the liquid supply pipe, and the liquid passage hole is connected to the liquid supply pipe.

9. The air reverse circulation drilling slag guide device for permafrost as described in claim 1, characterized in that, The external drill bit (4) includes a cylinder (401), on which a plurality of vertical plates (402) are connected, with gaps between adjacent vertical plates (402), and the end of the cylinder (401) has a plurality of cutting teeth (403).

10. The air reverse circulation drilling slag guide device for permafrost as described in claim 9, characterized in that, The innermost ends of the plurality of cutting teeth (403) form an inner circle, the diameter of which is smaller than the inner diameter of the cylinder (401).

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