Shielded pressure relief inner discharge drill pipe and tight fitting plug-in machine tool

Abstract

The application discloses a shield pressure-releasing inner slag-discharging drill rod and a tight-fitting inserting machine tool, and belongs to the technical field of drilling tools. The shield pressure-releasing inner slag-discharging drill rod comprises a special-shaped outer tube, a special-shaped inner tube, a special-shaped sieve hole plate strip and a special-shaped sealing ring. An axial groove is arranged on the outer circle of the special-shaped outer tube. The special-shaped sieve hole plate strip is tightly and pressingly inserted into the axial groove on the outer surface of the special-shaped outer tube. The special-shaped sealing ring is arranged at one end of the special-shaped inner tube. The tight-fitting inserting machine tool is provided. The special-shaped inner tube can be inserted into the special-shaped inner cavity of the special-shaped outer tube by using the tight-fitting inserting machine tool. The contact curved surface of the special-shaped inner tube and the special-shaped outer tube realizes tight fitting after being coated with glue. The special-shaped sieve hole plate strip is tightly and pressingly inserted into the bottom of the axial groove on the special-shaped outer tube. The diameter of the slag inlet of the slag discharge channel is smaller than the diameter of the slag outlet. The slag discharge channel is prevented from being blocked by coal slag particles. By utilizing the available condition that the special-shaped inner tube is in a suspended state at the thread part, the reference hole for adjusting the coaxiality is arranged at the thread end of the special-shaped outer tube.

Description

Technical Field

[0001] This invention relates to the field of coal mine gas drainage drilling technology, and in particular to a shield-supported pressure relief internal slag discharge drill rod and its tight-fitting insertion tool. Background Technology

[0002] Currently, the drill rods used for in-seam drilling in soft, outburst-protruding coal seams in China mainly include grooved drill rods, ribbed drill rods, and prismatic grooved drill rods, with patent numbers ZL200610111830.7, ZL200920088879.4, and ZL200910064973.0, respectively, and the applicant is Henan Polytechnic University. The technical features of these three patents mainly lie in the improvement of the drill rod's external shape. By adding spiral grooves, spiral ribs, and axial ridges to the drill rod's surface, the slag removal effect is improved. These improvements in the drill rod's external shape have also been applied to cable-driven drill rods used in directional drilling and have been used in China for over fifteen years, playing a certain role in improving slag removal and increasing drilling depth. A common feature of these drill rods is that they use airflow, waterflow, or a combination of air and water as the slag removal medium, and the annular space between the drill rod's surface and the borehole wall serves as the slag removal channel, referred to as the external slag removal channel. Because the outer wall of the external slag discharge channel is a soft coal seam with a high gas pressure gradient, drilling dynamics such as ground stress and coal blasting can cause the channel to collapse. The external slag discharge channel is an extremely unstable channel, and the difficulty in slag discharge is the fundamental reason for the difficulty in drilling soft, outburst-prone coal seams. Furthermore, the existence of the external slag discharge channel requires the drill rod diameter to be smaller than the drill bit diameter, resulting in a large disturbance space for the drill rod and consequently severe borehole deviation. Although directional drilling technology can solve the borehole deviation problem, it is also difficult to drill in soft, outburst-prone coal seams, and the cost of losing the drill bit due to pressure is too high. Therefore, directional drilling technology is rarely used in soft, outburst-prone coal seams. Shallow borehole depth and severe borehole deviation in soft, outburst-prone coal seams have become bottleneck problems for gas extraction and gas control.

[0003] To address the challenges of difficult slag removal, shallow drilling depth, and severe borehole deviation in soft, outburst-prone coal seams, the applicant proposes a "shield-supported pressure-relief drilling" approach. Its core components include: First, abandoning external slag removal channels and constructing internal slag removal channels within the drill pipe to solve the slag removal difficulties in soft, outburst-prone coal seams; Second, abandoning external slag removal channels, and if possible, ensuring the drill pipe diameter is equal to or close to the drill bit diameter, limiting the drill pipe's disturbance space and thus reducing borehole deviation; Third, drill bit jamming is a common phenomenon in drilling soft, outburst-prone coal seams, with only 20%-30% of the drill cuttings originating from the drill bit, while 70%-80% originate from borehole wall deformation and damage. Therefore, it is necessary to install slag relief and pressure-relief channels radially on the drill pipe, enabling the drill pipe to have its own pressure-relief function. To achieve the above drilling concept, a specially structured drill pipe is required. The structural features of the drill pipe are: an annular flow supply channel in the axial direction, an internal slag removal channel at the center of the axial direction, and a slag relief and pressure-relief channel composed of numerous radial holes in the radial direction.

[0004] Based on the aforementioned drilling concept and drill pipe structure, the applicant has applied for several patents, application numbers: 202110726041.9; 202110903532.6; 202111152968.2; 202111237232.5; 202210013684.3; 202210249463.6. These patents address the issue of "embedded sealing between the outer pipe and the inner slag discharge pipe," but fail to provide a specific implementation plan for this sealing. This is crucial for ensuring the isolation between the supply channel and the slag discharge channel; otherwise, leakage will occur due to the connection between the supply channel and the slag discharge channel. These patents also mention the requirement of "coaxiality between the outer pipe and the inner slag discharge pipe," but existing hot-rolled steel pipes or precision cold-drawn special-shaped steel pipes cannot achieve precise wall thickness. Without high-cost processing methods, it is difficult to achieve coaxiality between the outer pipe and the inner slag discharge pipe. If they are not coaxial, the connection between the two drill pipes... This would make it difficult to achieve a seal between the two inner slag discharge pipes, leading to a connection and leakage between the supply channel and the inner slag discharge channel. These patents mention that the radial screen holes (slag discharge channels) for slag discharge and pressure relief should have an inlet diameter smaller than the outlet diameter as much as possible. They also propose to construct radial holes in the outer and inner pipes to form stepped holes, and to process inverted conical holes. They also propose to use the method of welding conical hole strips to achieve an inlet diameter smaller than the outlet diameter. Stepped holes and inverted conical holes will increase machining costs, while welding conical hole strips will reduce the strength of the drill rod.

[0005] To address the aforementioned problems, this invention addresses the following five aspects: First, it proposes a precision cold-drawn shaped outer tube with an axial groove on its outer circumference and an inner arc-shaped rib on its inner hole as a shaped tube for drill rods; Second, it proposes a shaped perforated plate that can adapt to the bending and twisting deformation of drill rods. By tightly fitting the shaped perforated plate into the axial groove on the shaped outer tube, it not only ensures that the diameter of the slag inlet of the slag discharge channel is smaller than the diameter of the slag outlet, preventing the slag discharge channel from being blocked by coal slag particles, but also minimizes the impact of welding on the strength of the drill rod; Third, it proposes a shaped inner tube with a limiting rib on its outer circumference as an inner slag discharge pipe. The limiting rib of the shaped inner tube and the inner arc-shaped rib of the shaped outer tube can be fitted in various ways, allowing the shaped outer tube and the shaped inner tube to be stressed synchronously, not only... The top screw fixing between the two can be eliminated, and the overall strength of the drill pipe is improved; Fourth, taking advantage of the special structure of the irregular outer tube and the irregular inner tube, a tight-fit insertion tool is proposed. Using this tight-fit insertion tool, the irregular inner tube can be inserted into the inner cavity of the irregular outer tube after being coated with glue, and the irregular inner tube and the irregular outer tube can achieve a tight fit or interference fit, thereby ensuring the isolation and sealing of the supply channel and the slag discharge channel; Fifth, in view of the problem of uneven wall thickness of the irregular outer tube, taking advantage of the available condition that the irregular inner tube is in a suspended state at the threaded part, it is proposed to set a reference hole at the threaded end of the irregular outer tube. The reference hole and the thread are machined in one cut. With the reference hole as the reference, various methods can be used to force the irregular inner tube at the threaded part to be coaxial with the reference hole, that is, coaxial with the thread of the irregular outer tube. Summary of the Invention

[0006] This invention addresses the problems existing in the prior art by providing a shield-protected pressure relief internal slag discharge drill rod and its tight-fitting insertion tool.

[0007] The technical solution adopted to achieve the above objectives is:

[0008] A shield-support pressure relief internal slag discharge drill rod and its tight-fitting insertion tool are disclosed. The drill rod comprises a shaped outer tube and a shaped inner tube. The drill rod further comprises a shaped perforated plate and a shaped sealing ring. An axial groove is provided on the outer circumference of the shaped outer tube. The shaped perforated plate is tightly pressed into the axial groove and fixed therein by partial electric welding. The shaped sealing ring is installed at one end of the shaped inner tube. The tight-fitting insertion tool inserts the shaped inner tube into the shaped inner cavity of the shaped outer tube, achieving a tight fit between the inner and outer tubes after adhesive application. This tight fit forms a flow channel, and the inner hole of the inner tube serves as an internal slag discharge channel. The drill rod has several radially arranged slag discharge channels, which are connected to the internal slag discharge channels and are isolated and sealed from the flow channel.

[0009] Furthermore, the inner surface of the irregular outer tube is provided with 2-3 axial inner arc surface ribs, and the outer radius of the irregular inner tube is equal to or slightly larger than the arc radius of the inner arc surface ribs of the irregular outer tube, so that the irregular inner tube and the irregular outer tube can achieve a tight fit; the outer circle of the irregular inner tube is provided with 4-6 axial positioning ribs, so that the irregular inner tube and the irregular outer tube can simultaneously bear the torque of the drill rod.

[0010] Furthermore, a male thread is machined at one end of the irregularly shaped outer tube, and a male end reference hole is machined in the inner hole of the male thread; a female thread is machined at the other end of the irregularly shaped outer tube, and a female end reference hole is machined at the root of the female thread.

[0011] Furthermore, the outer circumference of the irregularly shaped outer tube is machined with spiral grooves or spiral ribs.

[0012] Furthermore, the male and female reference holes of the shaped outer tube serve as references for the coaxial positioning of the shaped inner tube. Taking advantage of the fact that the shaped inner tube is suspended at the male and female ends, a forced positioning block or ring is used to force the shaped inner tube to be coaxial with the reference holes. Coaxiality adjustment is achieved by relieving internal stress through heating. After adjustment, the forced positioning block or ring can be removed. If the shaped inner tube is made of a double-resistance polymer material, a forced positioning ring with a flow channel can be used for coaxial positioning, eliminating the need for heating, and the forced positioning ring does not need to be removed.

[0013] Furthermore, the slag discharge channel is radially opened at the bottom of the axial groove and passes through the walls of the irregular outer tube and the irregular inner tube in sequence.

[0014] Furthermore, the irregularly shaped screen plate has several screen holes that cooperate with the slag discharge channel. The diameter of the screen holes is smaller than the diameter of the slag discharge channel. The screen holes on the irregularly shaped screen plate coaxially cover the slag discharge channel. The screen holes can be straight holes or conical holes.

[0015] Furthermore, the tight-fitting insertion tool includes a wedge mandrel, a slotted round tube, several wedge pressure blocks, several reset rubber rings, and a tension cylinder;

[0016] The tension cylinder includes a cylinder body and a piston rod. The wedge mandrel is connected to the piston rod. The slotted tube is fixedly connected to the cylinder body through a connector. The wedge mandrel is located in the inner hole of the slotted tube. Several slots are radially opened on the slotted tube. The wedge pressure block is placed in the slot of the slotted tube and matches and contacts the inclined surface of the wedge mandrel. Multiple grooves are opened circumferentially on each wedge pressure block and the slotted tube. The reset rubber ring is placed in the groove.

[0017] Furthermore, the outer diameter of the grooved circular tube is slightly smaller than the inner diameter of the irregularly shaped inner tube.

[0018] The beneficial effects of this invention are as follows:

[0019] 1. This invention addresses the problem of sealing between irregularly shaped outer and inner tubes. Utilizing the irregular inner bore of the outer tube, a tight-fitting insertion tool is proposed to achieve a tight fit between the outer and inner tubes after applying adhesive. This ensures the isolation and sealing between the supply channel and the slag discharge channel, preventing leakage caused by the connection between the supply channel and the slag discharge and pressure relief channel.

[0020] 2. A special-shaped outer tube with an axial groove on its outer circumference and an inner arc-shaped rib on its inner hole is proposed. A special-shaped inner tube with a positioning rib on its outer circumference is proposed as an inner slag discharge pipe. The positioning rib of the special-shaped inner tube and the inner arc-shaped rib of the special-shaped outer tube can adopt various matching methods to enable the special-shaped outer tube and the special-shaped inner tube to bear torque synchronously. This can effectively prevent misalignment of the screen holes on the special-shaped outer tube and the special-shaped inner tube, eliminate the need for the set screw fixing between the special-shaped outer tube and the special-shaped inner tube, improve the overall strength of the shield protection pressure relief drill rod, and bring a series of advantages.

[0021] 3. This invention proposes irregularly shaped perforated plate strips, which are tightly fitted into the bottom of the axial groove on the irregularly shaped outer tube, so that the diameter of the slag inlet of the slag discharge channel is smaller than the diameter of the slag outlet, which can prevent the slag discharge channel from being blocked by coal slag particles. The use of partial electric welding instead of full-length welding can significantly reduce the impact of welding and welding of the perforated plate strips on the strength of the drill rod.

[0022] 4. This invention addresses the problem of uneven wall thickness in irregularly shaped outer tubes by utilizing the available condition that the inner slag discharge tube is suspended at the threaded end. It proposes to set a positioning reference hole at the threaded end of the irregularly shaped outer tube. The positioning reference hole and the thread are machined in one cut. Using the reference hole as a reference, various methods can be used to force the irregularly shaped inner tube to be coaxial with the reference hole, that is, coaxial with the irregularly shaped outer tube. Attached Figure Description

[0023] Figure 1 This is a schematic diagram of the overall design of the shield-protected pressure relief internal slag discharge drill rod of the present invention;

[0024] Figure 2 This is a structural diagram of the irregular outer tube of the shield-protected pressure relief internal slag discharge drill rod of the present invention;

[0025] Figure 3 This is a structural diagram of the irregular inner tube of the shield-protected pressure relief internal slag discharge drill rod of the present invention;

[0026] Figure 4 This is a diagram showing the fit between the irregularly shaped sealing ring and the irregularly shaped inner tube of the shield-protected pressure relief internal slag discharge drill rod of the present invention;

[0027] Figure 5 This is a structural diagram of the irregularly shaped perforated plate strip of the shield-protected pressure relief internal slag discharge drill rod of the present invention;

[0028] Figure 6This is a diagram showing the tight fit between the irregularly shaped perforated plate strip and the axial groove of the present invention;

[0029] Figure 7 This is a schematic diagram of the overall design of the insert fitting tool of the present invention;

[0030] Figure 8 These are drawings of the main components of the tight-fitting insertion tool of the present invention;

[0031] Figure 9 This is a schematic diagram of the insertion principle of the insertion tool of the present invention.

[0032] Figure 10 This is a diagram showing the male and female thread connection of the shield-protected pressure relief internal slag discharge drill rod of the present invention.

[0033] Among them, 1-Irregular outer tube, 11-Inner arc surface rib, 12-Axial groove, 13-Male thread, 14-Female thread, 15-Male end reference hole, 16-Female end reference hole, 17-Spiral groove, 2-Irregular inner tube, 21-Positioning rib, 3-Irregular screen hole strip, 31-Screw hole, 4-Irregular sealing ring, 5-Tight fit insertion tool, 51-Wedge mandrel, 52-Groove round tube, 521-Groove, 53-Wedge pressure block, 54-Reset rubber ring, 55-Pull cylinder, 551-Piston rod, 552-Cylinder body, 6-Flow supply channel, 7-Inner slag discharge channel, 8-Slag discharge channel.

[0034] The accompanying drawings are for illustrative purposes only and should not be construed as limiting the scope of this patent. To better illustrate this embodiment, some components in the drawings may be omitted, enlarged, or reduced, and do not represent the actual dimensions of the product. It is understandable to those skilled in the art that some well-known structures and their descriptions may be omitted in the drawings. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0036] like Figure 1-10 As shown, this embodiment discloses a shield-supported pressure relief internal slag discharge drill rod and its tight-fitting insertion tool; wherein, Figure 1This is a schematic diagram of the overall design of the shield-supported pressure relief internal slag discharge drill rod of the present invention. The shield-supported pressure relief internal slag discharge drill rod includes a shaped outer tube 1, a shaped inner tube 2, a shaped perforated plate 3, and a shaped sealing ring 4. The outer circumference of the shaped outer tube 1 is provided with an axial groove 12. The shaped perforated plate 3 is tightly fitted and pressed into the bottom of the axial groove 12. The shaped sealing ring 4 is installed at one end of the shaped inner tube 2. The shaped inner tube 2 is inserted into the shaped inner cavity of the shaped outer tube 1 using a tight-fitting insertion tool 5, so that the shaped inner tube 2 and the shaped inner tube 1 are tightly fitted together. The outer tube 1 achieves a tight fit after gluing. After the outer tube 1 and the inner tube 2 are tightly fitted together, a supply channel 6 is formed. The inner hole of the inner tube 2 is an inner slag discharge channel 7. Several slag discharge channels 8 are radially arranged on the inner slag discharge drill rod of the shield protection pressure relief system. The slag discharge channels 8 have the function of slag discharge and pressure relief on the inner slag discharge drill rod. The slag discharge channels 8 are constructed along the radial direction of the drill rod, or they can be constructed along the radial deflection direction. The slag discharge channels 8 are connected to the inner slag discharge channels 7, and the slag discharge channels 8 are isolated and sealed from the supply channel 6.

[0037] like Figures 1-2 As shown, in this embodiment, the shaped outer tube 1 is made of cold-drawn shaped tubing, and two or three axial inner arc-shaped ribs 11 are evenly distributed in the inner hole of the shaped outer tube 1. Figure 1 As can be seen from the sectional view at point BB, the outer radius of the irregular inner tube 2 is equal to or slightly larger than the radius of the inner arc surface rib 11, enabling a tight fit between the irregular inner tube 2 and the irregular outer tube 1. Furthermore, both ends of the irregular outer tube 1 are machined with male threads 13 and female threads 14 respectively, based on the upsetting or friction welding joint. Simultaneously with machining the male and female threads, a male end reference hole 15 is machined in the inner hole of the male thread, and a female end reference hole 16 is machined at the root of the female thread. The purpose of the reference holes is to forcefully adjust the coaxiality of the irregular inner tube 2 and the threads. The male end reference hole 15 and the female end 16 serve as coaxial positioning references. Taking advantage of the fact that the irregular inner tube 2 is suspended at the ends of the male and female threads, the coaxiality of the irregular inner tube 2 and the reference holes is forcibly adjusted. Before coaxial positioning, the coaxiality of the shaped inner tube 2 and the reference hole is first tested. If the coaxiality meets the requirements, forced coaxial positioning is not necessary. If the coaxiality does not meet the required accuracy, a forced positioning ring can be inserted between the reference hole and the shaped inner tube 2. Then, the shaped inner tube is heated using a hole heating device and cooled with water to eliminate the internal stress generated by forced positioning. After that, the positioning ring is removed, thus completing the coaxial positioning work. With the improvement of shaped tube processing technology and processing accuracy, it is not necessary to set male and female reference holes. If the shaped inner tube 2 is made of double-resistant polymer material, a forced positioning ring with a flow channel can be used for coaxial positioning without heating, and the forced positioning ring will not be removed.

[0038] like Figures 1-2As shown, 2-3 axial grooves 12 are provided on the outer circle of the irregular outer tube 1 in cooperation with the inner arc surface rib 11. Irregular screen plate strips 3 are embedded in the axial grooves 12. The irregular screen plate strips 3 are tightly fitted to the bottom of the axial grooves 12 by using the interlocking effect of the irregular concave and convex shapes.

[0039] like Figure 2 As shown, the outer circle of the irregular outer tube 1 is machined with 2-3 spiral grooves 17. In other embodiments, in addition to using spiral grooves 17, spiral ribs can also be used instead of spiral grooves 17. Spiral grooves 17 or spiral ribs have a cooling effect on the drill rod and can also improve the slag discharge efficiency of the slag discharge channel 8.

[0040] like Figures 3-4 As shown, the irregularly shaped inner tube 2 is made of precision cold-drawn tube, or it can be made of polymer material. The two ends of the irregularly shaped inner tube 2 are appropriately processed. An irregularly shaped sealing ring 4 is installed at one end of the irregularly shaped inner tube 2. The irregularly shaped sealing ring 4 is installed after the inner slag discharge drill rod is processed and assembled. A limiting rib 21 is provided on the outer circle of the irregularly shaped inner tube 2.

[0041] like Figures 5-6 As shown, the irregularly shaped perforated plate 3 has several perforations 31 that fit into the slag discharge channel 8. The diameter of the perforations 31 is smaller than the diameter of the slag discharge channel 8. The perforations 31 on the irregularly shaped perforated plate 3 coaxially cover the slag discharge channel 8. The function of the tight fit of the irregularly shaped perforated plate 3 is to ensure that the diameter of the slag inlet of the slag discharge channel 8 is smaller than the diameter of the slag discharge channel 8, thus preventing the slag discharge channel 8 from being blocked by coal slag. The irregularly shaped perforated plate 3 is pressed into the axial groove 12 by a tight fit. Alternatively, an adhesive can be applied to the axial groove 12 in advance to make the irregularly shaped perforated plate 3 firmly fixed in the axial groove 12. The tight fit of the irregularly shaped perforated plate into the axial groove can eliminate the need for welding or minimize welding.

[0042] In this invention, the outer radius of the irregular inner tube 2 is equal to or slightly larger than the radius of the inner arc surface rib 11 of the irregular outer tube 1. Utilizing the irregular inner hole characteristics of the irregular outer tube 1, and with the aid of... Figure 7 The tight-fitting insertion tool shown enables a tight fit between the irregular inner tube 2 and the irregular outer tube 1. Before the tight fit, sealant can be applied to the inner arc surface rib 11 to ensure a reliable seal between the mating surfaces.

[0043] like Figures 7-9As shown, the tight-fitting insertion tool 5 consists of a wedge mandrel 51, a slotted round tube 52, multiple wedge pressure blocks 53, multiple reset rubber rings 54, and a tension cylinder 55. Using the tight-fitting insertion tool 5, the irregularly shaped inner tube 2 is inserted into the irregularly shaped outer tube 1, achieving a tight fit between the irregularly shaped inner tube 2 and the inner arc surface rib 11 of the irregularly shaped outer tube 1, forming a flow channel 6 between the irregularly shaped inner tube 2 and the irregularly shaped outer tube 1. The wedge mandrel 51 is located in the inner hole of the slotted round tube 52, and the wedge pressure blocks 53 are placed in the slot 5 of the slotted round tube 52. The inclined wedge mandrel 53 and the inclined surface of the inclined wedge mandrel 51 are in contact. Each inclined wedge pressure block 53 and the through-groove tube 52 have multiple grooves on their circumference. The reset rubber ring 54 is placed in the grooves of the through-groove tube 52 and the inclined wedge pressure block 53. The outer diameter of the through-groove tube 52 is slightly smaller than the inner diameter of the irregular inner tube 2. The inclined wedge mandrel 51 is connected to the piston rod 551 of the tension cylinder 55. The through-groove tube 52 is connected to the cylinder body 552 of the tension cylinder 55 through a connector. The outer diameter of the through-groove tube 52 is slightly smaller than the inner diameter of the irregular inner tube 2. To achieve a tight fit between the irregular inner tube and the irregular outer tube, a heat fitting method can also be used. However, the choice of sealant is limited under heat fitting, and the sealing effect is relatively poor.

[0044] Figure 9 This is a schematic diagram illustrating the insertion principle of the tight-fit insertion tool described in this invention. When the irregularly shaped inner tube 2 and the irregularly shaped outer tube 1 are coaxially assembled, the through-groove round tube 52 of the tight-fit insertion tool is first inserted into the inner hole of the irregularly shaped inner tube 2, and its relative position to the irregularly shaped inner tube 2 is adjusted. Figure 9 As shown in (a), the hydraulic cylinder 55 then provides tension, causing the wedge spindle 51 to drive the wedge pressure block 53 to apply pressure to the inner wall of the irregular inner tube 2. This causes the outer circle of the irregular inner tube 2 to undergo elastic bending deformation, resulting in a local reduction in the outer diameter. Consequently, the minimum radius of the deformed irregular inner tube 2 is smaller than the radius of the inner arc surface rib 11 of the irregular outer tube 1. Figure 9 As shown in (b), the deformed inner tube 2 is inserted into the inner hole of the outer tube 1, as follows. Figure 9 As shown in (c), before insertion, adhesive can be applied to the inner arc surface rib 11 of the irregular outer tube 1. After the insertion is completed, the tension cylinder 55 resets, and the elastic deformation of the irregular inner tube 2 recovers, so that the irregular inner tube 2 and the irregular inner tube 1 achieve a tight fit after adhesive application. Figure 9 (d). After the irregular inner tube 2 and the irregular outer tube 1 are tightly fitted, the multiple axial limiting ribs 21 on the outer surface of the irregular inner tube 2 play a limiting and fixing role, so that the irregular inner tube 2 and the irregular outer tube 1 transmit the torque of the drill rod synchronously, avoiding mutual torsion and misalignment of the inner and outer tubes, which would lead to misalignment of the screen holes.

[0045] like Figure 10 As shown, based on the operating conditions of the internal slag removal drill rod under the shield pressure relief system, if only pneumatic or low-pressure hydraulic slag removal is used, the following can be adopted: Figure 10(a) shows the irregular sealing ring 4; if not only is wind-powered slag removal used, but also high-pressure hydraulic cavity creation and other permeability enhancement operations are implemented, the wall thickness of the irregular inner tube 2 can be increased, and the following methods can be adopted. Figure 10 (b) shows the irregular sealing ring 4.

[0046] In addition, before embedding the irregularly shaped screen plate 3, an adhesive can be applied to the axial groove 12 to ensure that the irregularly shaped screen plate 3 is tightly and securely fitted in the axial groove 12. If the relevant dimensions are properly matched, no additional welding process is generally required. When the size and structure of the drill rod change, there is a risk that the screen plate may fall off under the stress of the drill rod. For drill rods of specific sizes, the irregularly shaped screen plate 3 can be fixed in the axial groove 12 by brazing or spot welding to minimize the impact of welding on the strength of the drill rod.

[0047] In order to further improve the effect of synchronous transmission of drill rod torque between the irregular inner tube 2 and the irregular outer tube 1, in addition to using the axial ribs and adhesive application shown in the attached figure to limit the relative torsional misalignment between the irregular outer tube and the irregular inner tube, a method of using multiple fixing screws to fasten and fix the inner and outer tubes can also be used, which is also within the scope of protection of this invention.

[0048] In the description of this invention, it should be understood that the terms "center", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only used to facilitate the description of this invention and to simplify the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the scope of protection of this invention.

[0049] If the terms "first" or "second" are used in this document to define components, those skilled in the art should know that the use of "first" or "second" is merely for the convenience of describing the invention and simplifying the description, and unless otherwise stated, the above terms have no special meaning.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. However, these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A shield-supported pressure relief internal slag discharge drill rod and its tight-fitting insertion tool, wherein the shield-supported pressure relief internal slag discharge drill rod includes a special-shaped outer tube (1) and a special-shaped inner tube (2), characterized in that, The shield pressure relief internal slag discharge drill rod also includes a special-shaped screen plate (3) and a special-shaped sealing ring (4). The outer circle of the special-shaped outer tube (1) is provided with an axial groove (12). The special-shaped screen plate (3) is pressed into the axial groove (12) in a tight fit. The special-shaped sealing ring (4) is installed at one end of the special-shaped inner tube (2). The special-shaped inner tube (2) is inserted into the special-shaped inner cavity of the special-shaped outer tube (1) by a tight fitting insertion tool (5), so that the contact arc surface of the special-shaped inner tube (2) and the special-shaped outer tube (1) achieves a tight fit after applying glue. After the special-shaped outer tube (1) and the special-shaped inner tube (2) are tightly fitted, a flow channel (6) is formed. The inner hole of the special-shaped inner tube (2) is an internal slag discharge channel (7). The shield pressure relief internal slag discharge drill rod is radially provided with several slag discharge channels (8). The slag discharge channels (8) are connected to the internal slag discharge channels (7). The slag discharge channels (8) are isolated and sealed from the flow channel (6). The tight-fitting insertion tool (5) includes a wedge mandrel (51), a slotted round tube (52), several wedge pressure blocks (53), several reset rubber rings (54), and a tension cylinder (55). The tension cylinder (55) includes a cylinder body (552) and a piston rod (551). The wedge mandrel (51) is connected to the piston rod (551). The through-groove tube (52) is fixedly connected to the cylinder body (552) through a connector. The wedge mandrel (51) is located in the inner hole of the through-groove tube (52). The through-groove tube (52) has several through grooves (521) radially opened. The wedge pressure block (53) is placed in the through groove (521) of the through-groove tube (52) and matches and contacts the inclined surface of the wedge mandrel (51). Each wedge pressure block (53) and the through-groove tube (52) has a groove circumferentially opened. The reset rubber ring (54) is placed in the groove.

2. The shield-protected pressure relief internal slag discharge drill rod and its tight-fitting insertion tool according to claim 1, characterized in that, The inner surface of the irregular outer tube (1) is provided with 2-3 axial inner arc surface ribs (11). The outer radius of the irregular inner tube (2) is equal to or slightly larger than the arc radius of the inner arc surface ribs (11) of the irregular outer tube (1), so that the irregular inner tube (2) and the irregular outer tube (1) can achieve a tight fit. The outer circle of the irregular inner tube (2) is provided with 4-6 axial positioning ribs (21), so that the irregular inner tube (2) and the irregular outer tube (1) can simultaneously bear the torque of the drill rod.

3. The shield-protected pressure relief internal slag discharge drill rod and its tight-fitting insertion tool according to claim 2, characterized in that, One end of the irregular outer tube (1) is machined with a male buckle (13), and a male end reference hole (15) is machined in the inner hole of the male buckle (13). The other end of the irregular outer tube (1) is machined with a female buckle (14), and a female end reference hole (16) is machined at the root of the female buckle (14).

4. The shield-protected pressure relief internal slag discharge drill rod and its tight-fitting insertion tool according to claim 3, characterized in that, The outer circumference of the irregular outer tube (1) is machined with a spiral groove (17) or a spiral rib.

5. The shield-protected pressure relief internal slag discharge drill rod and its tight-fitting insertion tool according to claim 4, characterized in that, The male end reference hole (15) and female end reference hole (16) of the irregular outer tube (1) are the reference for the coaxial positioning of the irregular inner tube and the irregular inner tube. Taking advantage of the available condition that the irregular inner tube (2) is in a suspended state at the male and female buckle ends, a forced positioning block or forced positioning ring is used to force the irregular inner tube (2) to be coaxial with the reference hole. The coaxiality is adjusted by heating to eliminate internal stress. After the adjustment is completed, the forced positioning block or forced positioning ring is removed.

6. The shield-protected pressure relief internal slag discharge drill rod and its tight-fitting insertion tool according to claim 1, characterized in that, The slag discharge channel (8) is radially opened at the bottom of the axial groove (12) and passes through the wall thickness of the irregular outer tube (1) and the irregular inner tube (2) in sequence.

7. The shield-protected pressure relief internal slag discharge drill rod and its tight-fitting insertion tool according to claim 1, characterized in that, The irregularly shaped perforated plate (3) is provided with a number of perforated holes (31) in conjunction with the slag discharge channel (8). The diameter of the perforated holes (31) is smaller than the diameter of the slag discharge channel (8). The perforated holes (31) on the irregularly shaped perforated plate (3) coaxially cover the slag discharge channel (8). The width of the irregularly shaped sieve plate (3) is slightly larger than the width of the axial groove (12), and the irregularly shaped sieve plate (3) is pressed tightly into the axial groove (12).

8. The shield-protected pressure relief internal slag discharge drill rod and its tight-fitting insertion tool according to claim 1, characterized in that, The outer diameter of the grooved round tube (52) is slightly smaller than the inner diameter of the irregular inner tube (2).

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