Pressure relief and blowout prevention combined type spiral drilling tool for upward hole drilling and using method of pressure relief and blowout prevention combined type spiral drilling tool

Abstract

The invention belongs to the field of coal mine underground drilling, and particularly discloses a pressure-relief blowout-prevention combined spiral drilling tool for upward hole drilling and a using method thereof.The pressure-relief blowout-prevention combined spiral drilling tool comprises a spiral slag feeding drill bit, a sieve hole spiral drill rod section, a spiral drill rod section, a rotary slag discharging device and a drill tail slag collecting device which are arranged in an inclined upward drill hole; 2-4 continuous spiral blades are arranged on the outer surfaces of the spiral slag feeding drill bit, the screen hole spiral drill rod section and the spiral drill rod section, and a spiral slag discharging channel is formed between every two adjacent spiral blades; a plurality of slag inlets are formed in the spiral slag feeding drill bit, a plurality of radial slag inlets are formed in the spiral slag discharging channel of the screen hole spiral drill rod section, and the slag inlets and the slag inlets are all communicated with the air leakage slag discharging channel. According to the drilling tool, the gas leakage deslagging channel located in the center of the drilling tool is additionally arranged, in the drilling process, on one hand, the deslagging efficiency can be greatly improved, the drilling resistance is reduced, on the other hand, high-pressure gas can be prevented from being accumulated in a drill hole, and the pressure relief and blowout prevention functions are achieved.

Description

Technical Field

[0001] The invention relates to the field of underground drilling in coal mines, in particular to a pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling and a use method thereof. Background Art

[0002] Pre-extraction of coal seam gas through drilling is an effective technical measure to prevent and control coal and gas outbursts. However, when drilling in outburst coal seams, due to the influence of ground stress, gas pressure, drilling tool disturbance, etc., the drilling is prone to abnormal dynamic phenomena such as hole collapse, hole blockage, hole spraying, and drill sticking, which not only affects the drilling depth of the borehole, but also causes the gas spraying hole to exceed the limit, causing major safety hazards to on-site construction.

[0003] At present, coal mines mainly adopt measures to prevent blowouts by installing blowout prevention devices outside the borehole. These measures are passive technical measures after the borehole blowout occurs, and cannot actively prevent blowouts inside the borehole, especially cannot solve the blowouts caused by borehole blockage. If the borehole is blocked during the drilling process, the gas deep in the borehole will gradually gather, and then form a "gas bag" with a certain pressure and volume; when the blocked section of the borehole is suddenly unblocked, the gathered high-pressure gas will suddenly spray out, causing the orifice and tunnel gas to exceed the limit. The protruding coal seam has the characteristics of high ground stress, high gas pressure, and soft coal body. The borehole blockage phenomenon is inevitable during the drilling process. Therefore, blockage and blowout occur frequently during the drilling of the protruding coal seam.

[0004] Therefore, in response to this problem, there is an urgent need to develop a drill with pressure relief and blowout prevention functions and low drilling resistance to meet the needs of safe, efficient and deep hole drilling in soft and protruding coal seams. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a pressure relief and blowout prevention combined spiral drilling tool for upturned hole drilling and a method of using the same.

[0006] To achieve the above object, the present invention is implemented according to the following technical solutions:

[0007] One of the technical solutions of the present invention is a combined spiral drilling tool for pressure relief and blowout prevention for upward hole drilling, comprising a drill rod body arranged in an inclined upward borehole and a drilling rig for driving the drill rod body for drilling, the drill rod body comprising a spiral slag feeding drill bit, a sieve hole spiral drill rod section connected to the rear end of the spiral slag feeding drill bit, and a spiral drill rod section connected to the rear end of the sieve hole spiral drill rod section; the outer surfaces of the spiral slag feeding drill bit, the sieve hole spiral drill rod section and the spiral drill rod section are all provided with 2-4 continuous spiral blades, and a spiral slag discharge channel is formed between two adjacent spiral blades; the inner holes of the spiral slag feeding drill bit, the sieve hole spiral drill rod section and the spiral drill rod section are circular degassing and slag discharge channels of equal diameter; the spiral slag feeding drill bit is provided with a plurality of slag feeding ports, and the spiral slag discharge channel of the sieve hole spiral drill rod section is provided with a plurality of radial slag feeding holes, and the slag feeding ports and slag feeding holes are both connected to the degassing and slag discharge channel.

[0008] Furthermore, the sieve hole auger rod section is composed of a plurality of sieve hole auger rods, and the outer surface of each of the sieve hole auger rods is provided with 2-4 I-type spiral blades, and a first spiral slag discharge channel is formed between two adjacent I-type spiral blades, and a plurality of radial slag inlet holes are opened between the first spiral slag discharge channels of the sieve hole auger rod, and the slag inlet holes are connected with the circular air venting and slag discharge channel in the center of the sieve hole auger rod; one end of the sieve hole auger rod is provided with a male thread, and the other end is provided with a female thread.

[0009] Furthermore, the auger rod section is composed of a plurality of auger rods, each of which is provided with 2-4 type II spiral blades on its outer surface, and a second spiral slag discharge channel is formed between two adjacent type II spiral blades; the center of the auger rod is a circular air venting and slag discharge channel; each of the auger rods is provided with a male thread at one end and a female thread at the other end.

[0010] Furthermore, the spiral slag feed drill bit includes a supporting tube and a plurality of cutting edges. The cutting edge is arranged at the front end of the supporting tube. The cutting edge is a hollow structure. A slag feed port is between two adjacent cutting edges, and the slag feed port is connected to the center hole of the supporting tube. The outer surface of the supporting tube is provided with 2-4 type III spiral blades, and a third spiral slag discharge channel is formed between two adjacent type III spiral blades. The rear end of the supporting tube is provided with an internal thread that cooperates with the male thread of the sieve hole spiral drill rod.

[0011] Furthermore, the rear end of the spiral drill rod section is connected to a rotary slag discharge device, and the rear end of the rotary slag discharge device is connected to the drill tail slag collection device by sliding plug-in.

[0012] Furthermore, the rotary slag discharge device includes a shell, a male thread is provided at the front end of the shell, the front end of the shell is connected to the rear end of the spiral drill rod section through the thread, a slag discharge pipe is coaxially inserted in the rear end of the shell, a bearing is installed in the rear end of the shell, and the front end of the slag discharge pipe is fixed in the inner ring of the bearing.

[0013] Furthermore, the drill tail slag collection device includes a box body, which is a thin-walled hollow structure. A flexible slag inlet inclined upward is provided on one side of the box body, and the rear end of the slag discharge pipe of the rotating slag discharge device is slidably inserted in the flexible slag inlet; a gas extraction port connected to the gas extraction pipeline underground in the coal mine is provided on the top of the box body; the bottom of the box body is a funnel-shaped slag discharge port, and a removable baffle is installed at the slag discharge port to close the box body during drilling.

[0014] A second technical solution of the present invention is a method for using a pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling, comprising the following steps:

[0015] Step 1: Move the drilling rig to the designed drilling position;

[0016] Step 2: Assemble the auger rod section, the screen hole auger rod section and the auger slag drill bit into a drill rod body and then install it on the drilling rig;

[0017] Step 3: Install the rotary slag discharge device at the rear end of the auger rod section;

[0018] Step 4: Adjust the position of the drill tail slag collecting device, slide and plug the flexible slag inlet of the drill tail slag collecting device with the slag discharge pipe of the rotary slag discharge device, and close the slag discharge port of the drill tail slag collecting device with the baffle; connect the extraction port on the top of the drill tail slag collecting device with the gas extraction pipeline;

[0019] Step 5: Adjust the drilling rig construction angle, start the drilling rig to drive the drill rod body to drill;

[0020] Step 6: During drilling, according to the amount of drill cuttings accumulated inside the drill tail cuttings collecting device, the baffle is promptly pulled out to unload the drill cuttings in the drill tail cuttings collecting device, and then the baffle is inserted to continue drilling.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] (1) When the pressure relief and blowout prevention combined spiral drill for upward hole drilling of the present invention is used to perform upward hole drilling in a coal (rock) layer, a part of the drill cuttings on the outside of the drill pipe will be discharged outwardly through the spiral conveying action of the blades on the outer surface of the drill pipe, and the other part will enter the degassing and degassing channel in the center of the drill pipe through the degassing port at the front section of the spiral degassing drill bit and the degassing holes on the surface of the sieve hole spiral drill pipe. The drill cuttings entering the degassing and degassing channel will be discharged outwardly along the inner hole of the drill pipe under the action of the downward force of gravity. The rotation of the drill pipe will reduce the resistance between the drill cuttings and the wall surface of the inner hole of the drill pipe, thereby accelerating the sliding speed. The gas inside the borehole can enter the degassing and degassing channel in the center of the drill pipe through the degassing port of the spiral degassing drill bit and the numerous degassing holes on the sieve hole spiral drill pipe, and directly connect to the outside of the borehole, which can effectively solve the blowout caused by abnormal gas outflow in the hole and the blowout caused by borehole collapse and blockage.

[0023] (2) The spiral slag feed drill bit and the screen hole spiral drill rod of the combined spiral drilling tool both have the function of slag feed and pressure relief, which can greatly reduce the rotational resistance of the drill rod. Under the condition of a certain drilling rig torque, it is beneficial to increase the drilling depth of soft coal seam boreholes, thereby improving the effect of drilling gas extraction.

[0024] (3) In addition to the spiral blade spiral slag removal function, the combined spiral drilling tool also fully utilizes the gravity-assisted slag removal function, which can greatly improve the slag removal efficiency when drilling in soft coal seams, thereby improving the drilling efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 The present invention is a schematic structural diagram of a combined spiral drilling tool for pressure relief and blowout prevention for upturned hole drilling according to an embodiment of the present invention.

[0026] Figure 2 It is a three-dimensional structural diagram of the spiral slag drill bit of the present invention.

[0027] Figure 3 It is a three-dimensional structural diagram of the sieve hole spiral drill rod of the present invention.

[0028] Figure 4 It is a cross-sectional view of the sieve hole spiral drill rod of the present invention.

[0029] Figure 5 The figure is a schematic diagram of the connection between the spiral slag feeding drill bit and the sieve hole spiral drill rod section of the present invention.

[0030] Figure 6 The three-dimensional structure diagram of the spiral drill rod segment of the present invention.

[0031] Figure 7 It is a cross-sectional view of the spiral drill rod section of the present invention.

[0032] Figure 8 It is a three-dimensional schematic diagram of the rotary slag discharge device of the present invention.

[0033] Fig. 9 It is a structural diagram of the rotary slag discharge device of the present invention.

[0034] Fig.10 It is a three-dimensional schematic diagram of the drill tail slag collection device of the present invention. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with embodiments. The specific embodiments described herein are only used to explain the present invention and are not used to limit the invention.

[0036] like Figure 1-Figure 10As shown, this embodiment exemplarily shows a pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling, including a drill rod body arranged in an inclined upward borehole and a drilling rig 6 for driving the drill rod body for drilling, the drill rod body including a spiral slag feeding drill bit 1, a sieve hole spiral drill rod section 2 connected to the rear end of the spiral slag feeding drill bit 1, and a spiral drill rod section 3 connected to the rear end of the sieve hole spiral drill rod section 2; the outer surfaces of the spiral slag feeding drill bit 1, the sieve hole spiral drill rod section 2 and the spiral drill rod section 3 are each provided with two continuous spiral blades, and a spiral slag discharge channel is formed between two adjacent spiral blades; the inner holes of the spiral slag feeding drill bit 1, the sieve hole spiral drill rod section 2 and the spiral drill rod section 3 are circular degassing and slag discharge channels of equal diameter; the spiral slag feeding drill bit 1 is provided with a plurality of slag feeding ports, and the spiral slag discharge channel of the sieve hole spiral drill rod section 2 is provided with a plurality of radial slag feeding holes, and the slag feeding ports and the slag feeding holes are both connected to the degassing and slag discharge channel. When drilling an upward hole, part of the drill cuttings outside the drill pipe will be discharged outward through the spiral conveying action of the drill pipe's outer blades, and the other part will enter the degassing and deslagging channel in the center of the drill pipe through the deslagging port at the front section of the spiral deslagging drill bit and the deslagging holes on the surface of the sieve-hole spiral drill pipe. The drill cuttings entering the degassing and deslagging channel will be discharged outward along the inner hole of the drill pipe under the action of the downward component of gravity. The rotation of the drill pipe will reduce the resistance between the drill cuttings and the wall of the inner hole of the drill pipe, thereby accelerating the sliding speed.

[0037] Specifically, if Figure 2 As shown, the spiral slag feed drill bit 1 includes a support tube 12 and a plurality of cutting edges 11. The cutting edge 11 is arranged at the front end of the support tube 12. The cutting edge 11 is a hollow structure. The slag feed port is between two adjacent cutting edges 11. The slag feed port is connected to the degassing and slag discharge channel of the support tube 12. Two type III spiral blades 13 are arranged on the outer surface of the support tube 12. A third spiral slag discharge channel is formed between the two type III spiral blades 13. An internal thread matching the male thread of the sieve hole spiral drill rod is arranged at the rear end of the support tube 12. The center of the spiral drill rod is a circular degassing and slag discharge channel. Each spiral drill rod is provided with a male thread at one end and a female thread at the other end. The sieve hole spiral drill rod is provided with a male thread at one end and a female thread at the other end. Figure 3 , Figure 4 , Figure 5As shown, the sieve hole auger rod section 2 is composed of a plurality of sieve hole auger rods, and the outer surface of each sieve hole auger rod is provided with two type I spiral blades 21, and a first spiral slag discharge channel is formed between the two type I spiral blades 21, and a plurality of radial slag inlet holes 22 are opened between the first spiral slag discharge channels of the sieve hole auger rod, and the slag inlet holes 22 are connected with the circular air release and slag discharge channel 23 in the center of the sieve hole auger rod 2; the auger rod section 3 is composed of a plurality of auger rods, and the outer surface of each auger rod is provided with two type II spiral blades 31, and a second spiral slag discharge channel is formed between the two type II spiral blades 31; it should be noted that the two type I spiral blades 21, the two type II spiral blades 31 and the two type III spiral blades 13 are sequentially connected to form an integral continuous spiral blade.

[0038] The spiral slag feeding drill bit 1 and the sieve hole spiral drill rod section 2 of this embodiment both have the functions of slag feeding and pressure relief, which can greatly reduce the rotation resistance of the drill rod.

[0039] like Figure 8 , Fig. 9 As shown, the rotary slag discharge device 4 includes a shell 41, the front end of the shell 41 is provided with a male thread, the front end of the shell 41 is connected to the rear end of the spiral drill rod section 3 through the thread, a slag discharge pipe 42 is coaxially inserted in the rear end of the shell 41, a bearing 43 is installed in the rear end of the shell 41, the front end of the slag discharge pipe 42 is fixed in the inner ring of the bearing 43, and the slag discharge pipe 42 and the shell 41 can rotate freely; the slag discharge pipe 42 is slidably plugged into the drill tail slag collecting device 5.

[0040] like Fig.10 As shown, the drill tail slag collecting device 5 includes a box body 51, which is a thin-walled hollow structure. A flexible slag inlet 52 inclined upward is provided on one side of the box body 51, and the rear end of the slag discharge pipe 42 of the rotary slag discharge device 4 is slidably inserted in the flexible slag inlet 52; a gas extraction port 54 connected to the gas extraction pipeline underground in the coal mine is provided on the top of the box body 51; the bottom of the box body 51 is a funnel-shaped slag discharge port, and a pluggable baffle 55 is installed at the slag discharge port to close the slag discharge port of the box body 51 during drilling.

[0041] In this embodiment, slag can be discharged firstly through the spiral channel, and then through the slag inlet 14 and the slag inlet hole 22 through the degassing slag discharge channel inside the drill rod body; in addition, since the inside of the borehole is connected to the outside of the borehole through the slag inlet channel of the slag inlet drill bit and the slag inlet hole on the sieve hole spiral drill rod, the accumulation of high-pressure gas inside the borehole can be avoided, thereby achieving the function of pressure relief and blowout prevention.

[0042] like Figure 6 , Figure 7As shown, the auger rod section 3 is composed of several auger rod sections, each of which is provided with a male thread at one end and a female thread at the other end, so as to adjust the length of the auger rod section 3 according to actual use needs. In order to prevent the gas and drilling debris in the inner hole of the sieve hole auger rod from escaping and being thrown out through the air (slag) hole on the drill rod body at the drilling hole mouth, several auger rods without sieve holes are connected to the rear end of the sieve hole auger rod.

[0043] During the up-hole drilling construction, part of the drill cuttings in the borehole is discharged outwards under the action of the spiral blades on the outer surface of the drill pipe, and the other part enters the inner hole of the drill pipe through the cutting inlet 14 of the spiral cutting drill bit and the cutting inlet holes 22 on the sieve hole spiral drill pipe, and then is discharged outwards along the inner hole of the drill pipe under the action of gravity to the drill tail cutting collection device for collection. The gas deep in the borehole can also enter the gas discharge channel in the center of the drill pipe through the cutting inlet 14 of the spiral cutting drill bit and the numerous cutting inlet holes 22 on the sieve hole spiral drill pipe, and directly connect to the outside of the borehole, which can effectively solve the spray holes caused by abnormal gas outflow in the hole and the spray holes caused by the collapse and blockage of the borehole.

[0044] In actual use, when drilling with the pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling of this embodiment, refer to Figure 1 The specific operation process is as follows:

[0045] Step 1: Move the drilling rig to the designed drilling position;

[0046] Step 2: Assemble the auger rod section 3, the sieve hole auger rod section 2 and the spiral slag drill bit 1 into a drill rod body and install it on the drilling rig; the length of the auger rod section 3 and the sieve hole auger rod section 2 can be lengthened as needed;

[0047] Step 3: Install the rotary slag discharge device 4 at the rear end of the auger rod section 3;

[0048] Step 4: adjust the position of the drill tail slag collecting device 5, slide and plug the flexible slag inlet 52 of the drill tail slag collecting device 5 with the slag discharge pipe 42 of the rotary slag discharge device 4, and close the slag discharge port with the baffle 55 of the drill tail slag collecting device 5; connect the extraction port 54 on the top of the drill tail slag collecting device 5 with the gas extraction pipeline;

[0049] Step 5: Adjust the drilling rig construction angle, start the drilling rig to drive the drill rod body to drill;

[0050] Step 6: During drilling, according to the amount of drill cuttings accumulated in the drill tail cuttings collecting device 5, the baffle is promptly pulled out to discharge the drill cuttings in the drill tail cuttings collecting device, and then the baffle is inserted to continue drilling.

[0051] The technical solution of the present invention is not limited to the above-mentioned specific embodiments. All technical variations made according to the technical solution of the present invention fall within the protection scope of the present invention.

Claims

1. A combined spiral drilling tool for pressure relief and blowout prevention for upward hole drilling, comprising a drill rod body arranged in an inclined upward hole and a drilling machine (6) for driving the drill rod body for drilling, characterized in that: The drill rod body comprises a spiral slag feeding drill bit (1), a sieve hole spiral drill rod section (2) connected to the rear end of the spiral slag feeding drill bit (1), and a spiral drill rod section (3) connected to the rear end of the sieve hole spiral drill rod section (2); the outer surfaces of the spiral slag feeding drill bit (1), the sieve hole spiral drill rod section (2) and the spiral drill rod section (3) are all provided with 2-4 continuous spiral blades, and a spiral slag discharge channel is formed between two adjacent spiral blades; the inner holes of the spiral slag feeding drill bit (1), the sieve hole spiral drill rod section (2) and the spiral drill rod section (3) are circular degassing and degassing channels with equal diameters; the spiral slag feeding drill bit (1) is provided with a plurality of slag feeding ports, and the spiral slag discharge channel of the sieve hole spiral drill rod section (2) is provided with a plurality of radial slag feeding holes, and the slag feeding ports and slag feeding holes are both connected to the degassing and degassing channel.

2. The pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling according to claim 1, characterized in that: The sieve hole auger rod section (2) is composed of a plurality of sieve hole auger rods, each of which is provided with 2-4 I-type spiral blades (21) on its outer surface, a first spiral slag discharge channel is formed between two adjacent I-type spiral blades (21), a plurality of radial slag inlet holes (22) are provided between the first spiral slag discharge channels of the sieve hole auger rod, the slag inlet holes (22) are connected to a circular air release slag discharge channel (23) at the center of the sieve hole auger rod; one end of the sieve hole auger rod is provided with a male thread, and the other end is provided with a female thread.

3. The pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling according to claim 1, characterized in that: The auger rod section (3) is composed of a plurality of auger rods, each of which is provided with 2-4 type II spiral blades (31) on its outer surface, and a second spiral slag discharge channel is formed between two adjacent type II spiral blades (31); the center of the auger rod is a circular air release and slag discharge channel; each of which is provided with a male thread at one end and a female thread at the other end.

4. The pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling according to claim 1, characterized in that: The spiral slag feed drill bit (1) comprises a support tube (12) and a plurality of cutting edges (11), wherein the cutting edge (11) is arranged at the front end of the support tube (12), the cutting edge (11) is a hollow structure, a slag feed port (14) is provided between two adjacent cutting edges (11), and the slag feed port (14) is connected to the central hole of the support tube (12); the outer surface of the support tube (12) is provided with 2-4 type III spiral blades (13), and a third spiral slag discharge channel is formed between two adjacent type III spiral blades (13); the rear end of the support tube is provided with an internal thread that matches the male thread of a sieve hole spiral drill rod.

5. The pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling according to any one of claims 1 to 4, characterized in that: The rear end of the spiral drill rod section (3) is connected to a rotary slag discharge device (4), and the rear end of the rotary slag discharge device (4) is connected to a drill tail slag collection device (5) by means of sliding plug-in.

6. The pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling according to claim 5, characterized in that: The rotary slag discharge device (4) comprises a shell (41), a front end of the shell (41) is provided with a male thread, the front end of the shell (41) is connected to the rear end of the spiral drill rod section (3) through the thread, a slag discharge pipe (42) is coaxially inserted in the rear end of the shell (41), a bearing (43) is installed in the rear end of the shell (41), and the front end of the slag discharge pipe (42) is fixed in the inner ring of the bearing (43).

7. The pressure relief and blowout prevention combined spiral drilling tool for upward hole drilling according to claim 6, characterized in that: The drilling tail slag collecting device (5) comprises a box body (51), the box body (51) is a thin-walled hollow structure, a side surface of the box body (51) is provided with an upwardly inclined flexible slag inlet (52), and the rear end of the slag discharge pipe (42) of the rotary slag discharge device (4) is slidably inserted in the flexible slag inlet (52); the top of the box body (51) is provided with a gas extraction port (54) connected to a gas extraction pipeline in the coal mine; the bottom of the box body (51) is a funnel-shaped slag discharge port, and a pluggable baffle (55) is installed at the slag discharge port to close the box body during drilling.

8. A method for using the pressure relief and blowout prevention combined spiral drilling tool for upturned hole drilling as claimed in claim 7, characterized in that: The following steps are involved: Step 1: Move the drilling rig to the designed drilling position; Step 2: Assemble the auger rod section (3), the sieve hole auger rod section (2) and the spiral slag drill bit (1) into a drill rod body and then install it on the drilling rig; Step 3: Install the rotary slag discharge device (4) at the rear end of the auger rod section (3); Step 4: Adjust the position of the drill tail slag collecting device (5), slide and plug the flexible slag inlet (52) of the drill tail slag collecting device (5) with the slag discharge pipe (42) of the rotary slag discharge device (4), and close the slag discharge port with the baffle (55) of the drill tail slag collecting device (5); connect the extraction port (54) at the top of the drill tail slag collecting device (5) with the gas extraction pipeline; Step 5: Adjust the drilling rig construction angle, start the drilling rig to drive the drill rod body to drill; Step 6: During drilling, according to the amount of drilling debris accumulated in the drilling tail debris collecting device (5), the baffle is promptly pulled out to discharge the drilling debris in the drilling tail debris collecting device, and then the baffle is inserted to continue drilling.

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