Shield pressure relief drilling tools for outburst coal seams and closed slag discharge system outside the hole

Abstract

The invention discloses a shield pressure relief drill tool for a protruding coal seam and an out-of-hole closed slag discharge system. The drill tool is composed of a plurality of sieve hole drill rods, a transition drill rod and a plug-in drill bit. The sieve hole drill rod and the transition drill rod are composed of different special-shaped outer tubes, inner tubes and tapered hole strips. The axial space between the outer tube and the inner tube is a flow supply channel of the drill tool. The central hole of the inner tube is an internal slag discharge channel of the drill tool. The slag discharge sieve hole is arranged in an axial groove of the special-shaped outer tube and is connected with the internal slag discharge channel. The tapered hole strip is welded in the axial groove of the special-shaped outer tube and the tapered hole is coaxially aligned with the slag discharge sieve hole. Male buckles and female buckles are arranged at both ends of the sieve hole drill rod. A female buckle connected to the male buckle of the sieve hole drill rod is arranged at one end of the transition drill rod, and a plug-in interface connected to the plug-in drill bit is arranged at the other end of the transition drill rod. The out-of-hole closed slag discharge system comprises a sliding closed tube placed in the inner cavity of the out-of-hole sieve hole drill rod, a sealing hole pipe moving device installed at the hole mouth and a hollow slag discharge water (wind) tail connected to the tail of the drill rod.

Description

Technical Field

[0001] The present invention relates to the technical field of gas extraction drilling in protruding coal seams, and specifically to drilling and hydraulic cavitation and permeability enhancement technology for gas extraction boreholes in protruding coal seams, and especially to shield pressure relief drill tools and an out-of-hole closed slag discharge system for protruding coal seams, which are used for drilling and hydraulic cavitation of boreholes in protruding coal seams, and help to improve the depth, straightness and hole quality of boreholes in protruding coal seams. Background Art

[0002] The drill rods used in the current drilling construction of gas extraction in the protruding coal seam are mostly grooved drill rods, rib drill rods, triangular grooved drill rods and triangular drill rods. The patent applicants for the first three types of drill rods are the applicant, Henan Polytechnic University, and the patent numbers are ZL200610111830.7, ZL200920088879.4, and ZL200910064973.0 respectively. The common feature of these drill rods is that they use wind flow, water flow or wind and water linkage to discharge slag. The annular space between the outer surface of the drill rod and the borehole wall is the slag discharge channel. Since the slag discharge channel is outside the outer wall of the drill rod, it is called an external slag discharge channel. There are two problems with the existing drill rods: on the one hand, due to the common occurrence of dynamic phenomena such as coal cannons in the hole during the drilling of protruding coal seams, the borehole wall is very easy to collapse, which makes the external slag discharge channel easily blocked. The poor slag discharge and the blockage of the external slag discharge channel make it difficult to ensure the drilling depth of the protruding coal seam. This is the main reason why the protruding coal seam is forced to adopt bottom rock tunnels and through-layer drilling; on the other hand, since the external slag discharge channel requires sufficient geometric space, the diameter of the drill rod is more than 20mm smaller than the diameter of the drill bit, and the disturbance space of the drill rod is too large, resulting in serious deviation of the borehole. The deviation distance of a 100-meter borehole is as high as 15m to 20m. The borehole deviates to the roof or floor of the coal seam too early, which in turn restricts the drilling depth and increases the probability of drill breakage.

[0003] In view of the problems of blockage of external slag discharge channel, limited drilling depth and serious drilling deviation in the current drill pipe, the applicant, Henan Polytechnic University, proposed the basic concept of shield pressure relief drilling, the basic characteristics of which are: using screen hole drill pipe and using internal slag discharge channel inside the drill pipe. The internal slag discharge channel is divided into two categories, namely annular internal slag discharge channel and central circular internal slag discharge channel, and the corresponding flow supply modes are central flow supply and circumferential flow supply.

[0004] For the shield and pressure relief drill rod with a central inner slag discharge channel for circular flow supply, the applicant has successively applied for four types of shield and pressure relief drill rods, including: Application No. CN202111237232.5, a shield and pressure relief sieve hole spiral drill rod with a circular flow supply protruding from a coal seam; Application No. CN202111152968.2, a sieve hole arc-edge drill rod with a flow protection hole and pressure relief for a protruding coal seam corner; Application No. CN202110903532.6, a shield and pressure relief sieve hole drill rod with a large diameter circumferential flow supply protruding from a coal seam; Application No. CN2021110726041.9, a sieve hole drill rod with a circular flow supply hole and pressure relief for a protruding coal seam. The common idea of ​​these applications is: using a double-walled screen hole drill rod to form a flow supply channel of the drill tool between the double walls of the double-walled drill rod, forming an internal slag discharge channel of the drill tool in the center hole of the double-walled drill rod, and setting a plurality of slag discharge screen holes in the radial direction of the double-walled drill rod that avoid the flow supply channel and are connected to the internal slag discharge channel. The diameter of the double-walled screen hole drill rod is equal to or slightly smaller than the diameter of the drill bit, thereby giving the drill rod four functions: first, shield protection function: using the drill rod to shield the drilling hole, curbing excessive hole collapse, which is beneficial to improving the hole quality; second, pressure relief function: using the slag discharge screen holes on the drill rod to promptly relieve the pressure of the borehole wall on the drill rod; third, straightening function: the diameter of the drill rod is equal to or slightly smaller than the diameter of the drill bit, limiting the disturbance space of the drill rod, and helping to improve the straightness of the borehole; fourth, internal slag discharge function: replacing the external slag discharge channel with the internal slag discharge channel, the hole mouth no longer discharges slag, so that the blockage of the internal slag discharge channel is unrelated to the hole collapse and coal cannon.

[0005] The above-mentioned drill rods focus on the basic concept of shield pressure relief drilling and provide feasible solutions for different combination structures. However, there are still some common problems and related problems that need to be further solved: First, the processing problem of the slag discharge screen hole. The slag discharge efficiency of the inverted cone slag discharge screen hole is high, but the processing efficiency is extremely low and the processing cost is extremely high, which is not conducive to mass production and reducing production costs. The slag discharge efficiency of the inverted step-shaped slag discharge screen hole is not ideal, and slag discharge screen holes of different diameters need to be processed on the outer tube and the inner tube respectively. The processing of the screen hole is also relatively difficult, which is not conducive to mass production; second, no technical approach is given for the coal slag produced by the drill bit to enter the internal slag discharge channel of the sieve hole drill rod, that is, no special coordination between the drill bit and the drill rod is given; third, no technical approach is given for the coal slag in the slag discharge channel of the sieve hole drill rod to be discharged outside the drill rod, that is, no out-of-hole slag system is given.

[0006] In view of the above problems, the present invention has accomplished the following four aspects of work: first, the tapered hole slats are introduced to avoid the processing difficulties, low processing efficiency and high processing costs of the inverted cone sieve holes and the inverted step sieve holes. On the premise of ensuring the slag feeding efficiency of the sieve holes, the processing cost of the sieve holes is greatly simplified and the processing efficiency of the sieve holes is improved; third, the method of introducing the transition drill rod is used to solve the problem of slag feeding from the drill bit into the sieve holes and the inner discharge channel; third, a hollow high-low pressure conversion valve is designed for the hollow structure of the shield pressure relief drill bit, so that the drill bit has the function of hydraulic cavitation during the process of withdrawing the drill bit; fourth, a targeted closed slag discharge system outside the hole is designed for the shield pressure relief drill bit. Summary of the invention

[0007] In view of the problems existing in the prior art, the present invention provides a shield-protected and pressure-relief drill tool for a protruding coal seam and an out-of-hole closed slag discharge system, aiming to improve the drilling depth, straightness and hole quality of the protruding coal seam and solve the problem of drilling spray holes in the protruding coal seam.

[0008] The technical solutions adopted to achieve the above objectives are:

[0009] The protruding coal seam shield pressure relief drill tool comprises a plurality of sieve hole drill rods connected in sequence, a transition drill rod and a plug-in drill bit, wherein the sieve hole drill rods are connected with each other by threaded connection, the sieve hole drill rods are connected with the transition drill rod by threaded connection, and the transition drill rod and the plug-in drill bit are connected by plug-in connection. The central inner hole of the protruding coal seam shield pressure relief drill tool is an inner slag discharge channel, the axial space between the double walls of the protruding coal seam shield pressure relief drill tool is a flow supply channel of the drill tool, and a large number of slag discharge sieve holes are arranged radially on the drill rod to avoid the flow supply channel.

[0010] Furthermore, the sieve hole drill rod comprises an outer tube, an inner tube and a tapered hole strip, the outer tube is a special-shaped outer tube, the outer surface of the special-shaped outer tube is provided with an axial groove, the inner hole of the special-shaped outer tube is provided with an axial protrusion corresponding to the position of the axial groove, and the number of the axial groove and the axial protrusion is two or three; the inner tube is a round tube, and the center hole of the inner tube is an internal slag discharge channel of the sieve hole drill rod; the special-shaped outer tube is embedded and sealed with the inner tube, the axial protrusion is installed in contact with the inner tube, and the tapered hole strip is installed in the axial groove; a plurality of slag discharge sieve holes connected to the internal slag discharge channel are provided in the axial groove of the special-shaped outer tube; the tapered hole strip is provided with tapered holes with the same number as the slag discharge sieve holes in the axial groove, and the tapered holes are coaxially matched with the slag discharge sieve holes one by one. The sieve hole drill pipe has a flow supply channel and an internal slag discharge channel in the axial direction, and the flow supply direction is opposite to the slag discharge direction; the sieve hole drill pipe has a large number of slag discharge sieve holes in the radial direction, and the slag discharge sieve holes are connected to the internal slag discharge channel but not to the flow supply channel. Therefore, an embedded seal is required between the special-shaped outer tube and the inner tube, and the contact surface of the special-shaped outer tube and the inner tube is kept sealed by shrink fitting, impregnation sealing and other processes.

[0011] Furthermore, the two ends of the special-shaped outer tube of the sieve hole drill pipe are converted into thick-walled round tubes by extrusion molding or friction welding and jointing, and male buckles and female buckles for connecting adjacent special-shaped outer tubes are processed on the thick-walled round tubes; a spiral groove is arranged on the outer arc surface of the special-shaped outer tube, and the size and shape of the spiral groove are not restricted. The function of the spiral groove is to increase the pressure relief function and cooling function of the sieve hole drill pipe. For extremely soft protruding coal seams, the spiral groove may not be arranged on the outer arc surface of the special-shaped outer tube. Although the pressure relief function of the drill pipe is weakened, the shield function of the drill pipe is increased, which is also within the protection scope of the present invention. The surface of the sieve hole drill pipe is sprayed with wear-resistant materials and other processes to increase the wear resistance and service life of the drill pipe, which is also within the protection scope of the present invention.

[0012] Furthermore, the diameter of the slag discharge screen hole of the sieve hole drill rod is less than one-third of the diameter of the inner tube; the minor diameter of the tapered hole on the tapered hole strip is smaller than the diameter of the slag discharge screen hole, and the major diameter of the tapered hole on the tapered hole strip is equal to the diameter of the slag discharge screen hole; the thickness of the tapered hole strip is less than the difference between the depth of the axial groove of the special-shaped outer tube and the depth of the spiral groove. After welding the tapered hole strip, the tapered hole strip is still at the lowest position on the surface of the sieve hole drill rod to facilitate slag gathering and discharge. It is also within the protection scope of the present invention to adopt the sieve hole orifice extrusion method, the sieve hole orifice surfacing method, the single-piece tapered hole welding method, the water jet or laser inverted tapered hole cutting method, the inverted tapered hole countersinking method and other methods to make the slag inlet diameter of the slag discharge screen hole smaller than the slag outlet diameter.

[0013] In order to increase the rubbing and crushing function of the conical hole slats facing the coal surface, methods such as indentation and spraying of wear-resistant particles can be implemented on the conical hole slats. The conical hole slats can also be made of wear-resistant steel or powder metallurgy materials. The conical holes can be punched or drilled. Similar related auxiliary technologies are also within the protection scope of the present invention. The processing of radial straight hole slag sieve holes is the most convenient. If the slag sieve holes are processed into inclined holes, it is more convenient to discharge slag from the slag sieve holes, which is also within the protection scope of the present invention. When the diameter of the radial slag sieve holes is about 1.5 times the depth of the slag sieve holes, the slag sieve holes are not easy to be blocked. When the geometric dimensions, strength and other factors of the sieve hole drill rod permit, the slag sieve holes with a diameter greater than about 1.5 times the depth can be designed. In this case, the conical hole slats can be eliminated.

[0014] Furthermore, the sieve hole drill rod comprises an outer tube and an inner tube that are inserted and matched, the inner tube is a round tube, and the central hole of the inner tube is an inner slag discharge channel of the sieve hole drill rod; the outer tube is a hot-twisted special-shaped outer tube formed by a hot-twisting method under a constrained state, the outer surface of the hot-twisted special-shaped outer tube forms a large-pitch spiral groove, the inner hole of the hot-twisted special-shaped outer tube forms a large-pitch cambered surface protrusion corresponding to the large-pitch spiral groove, the large-pitch cambered surface protrusion of the inner hole of the hot-twisted special-shaped outer tube is matched with the outer circle of the inner tube and supports the inner tube so that The outer tube and the inner tube remain coaxial, and the number of large-pitch spiral grooves and large-pitch cambered protrusions is two or three; a large-pitch tapered hole strip is installed in the large-pitch spiral groove, and a plurality of slag discharge screen holes connected to the internal slag discharge channel are arranged in the large-pitch spiral groove of the hot-twisted special-shaped outer tube; the large-pitch tapered hole strip is provided with tapered holes with the same number as the slag discharge screen holes in the large-pitch spiral groove, and the tapered holes are coaxially matched with the slag discharge screen holes one by one; the thickness of the large-pitch tapered hole strip is less than the depth of the large-pitch spiral groove.

[0015] Furthermore, the sieve hole drill rods are connected by sealed threads, the inner tubes of the sieve hole drill rods are connected by plug-in seals or lap seals, and the flow channel in the threaded connection between the sieve hole drill rods is an annular flow channel. A spiral groove may be added to the outer arc of the female buckle of the sieve hole drill rod, or it may not be added. Adding a spiral groove is beneficial to cooling the threaded part of the drill rod, but it weakens the strength of the female buckle. Whether to process the spiral groove on the outer arc of the female buckle of the sieve hole drill rod can be determined according to the specific implementation conditions.

[0016] Furthermore, the transition drill rod is composed of a deep groove special-shaped outer tube, a blind hole inner tube and dense tapered hole slats, the outer surface of the deep groove special-shaped outer tube is provided with an axial groove, the inner hole of the deep groove special-shaped outer tube is provided with an axial protrusion corresponding to the position of the axial groove, and the number of the axial groove and the axial protrusion is three or four; the blind hole inner tube is a round tube with a tapered plug at one end, and the center hole of the blind hole inner tube is the internal slag discharge channel of the transition drill rod; the deep groove special-shaped outer tube and the blind hole inner tube are embedded and sealed, and a plurality of slag discharge sieve holes connected to the internal slag discharge channel are provided in the axial groove of the deep groove special-shaped outer tube; the dense tapered hole slats are installed in the axial groove by brazing or spot welding, and the dense tapered hole slats are provided with tapered holes with the same number as the slag discharge sieve holes in the axial groove, and the tapered holes are coaxially matched with the slag discharge sieve holes one by one.

[0017] Furthermore, the outer diameter of the blind hole inner tube of the transition drill rod is smaller than the outer diameter of the inner tube of the sieve hole drill rod, the depth of the axial groove of the deep groove special-shaped outer tube of the transition drill rod is greater than the depth of the axial groove of the special-shaped outer tube of the sieve hole drill rod; the slag discharge screen hole density of the transition drill rod is greater than the slag discharge screen hole density of the sieve hole drill rod, and the installation method of the dense cone hole slats of the transition drill rod is the same as the installation method of the cone hole slats of the sieve hole drill rod.

[0018] The transition drill rod is a special sieve drill rod with stronger slag discharge capability. The axial grooves guiding the drill bit to drill slag are deeper, the number of axial grooves is more, and the density of the slag discharge sieve holes is greater. The transition drill rod is used in conjunction with a plug-in drill bit. The coal slag produced by the drill bit first enters the axial grooves and then enters the internal slag discharge channel through the dense slag discharge sieve holes. For medium-hard coal seams, spiral grooves may also be provided on the outer arc surface of the deep groove special-shaped outer tube of the transition drill rod to improve the slag crushing and pressure relief capabilities of the transition drill rod. For soft coal seams, spiral grooves may not be provided on the outer arc surface of the deep groove special-shaped outer tube of the transition drill rod to improve the shielding capability of the transition drill rod.

[0019] Furthermore, one end of the deep groove special-shaped outer tube of the transition drill rod is converted into a thick-walled round tube by extrusion molding or friction welding and jointing, and a female buckle connected to the male buckle of the sieve hole drill rod is processed on the thick-walled round tube; the other end of the deep groove special-shaped outer tube of the transition drill rod is provided with a radial top screw hole for installing a plug-in drill bit.

[0020] Furthermore, one end of the plug-in drill bit that cooperates with the deep groove special-shaped outer tube is provided with a drill shank, and the other end of the plug-in drill bit is provided with a cutting portion and a plurality of flow supply holes; the outer shape and size of the drill shank are the same as the inner hole shape and size of the deep groove special-shaped outer tube of the transition drill rod. During installation, the drill shank is inserted into the inner hole of the deep groove special-shaped outer tube, and the plug-in drill bit and the transition drill rod are fastened by plugging through the top screw and the radial top screw hole of the fixed deep groove special-shaped outer tube, so that the plug-in drill bit and the transition drill rod are plugged in and fastened. The reason why the drill bit adopts a plug-in connection instead of a threaded connection is that the plug-in connection can use the groove of the special-shaped drill shank to axially dock with the axial groove of the transition drill rod, which can reduce the loss of slag removal power and enable the drilled coal slag to enter the inner slag removal channel quickly and efficiently.

[0021] Furthermore, a hollow high-low pressure conversion valve is installed between the screen hole drill rod and the transition drill rod, so that the drill has the function of high-pressure water jet hole making or slot cutting when the drill is withdrawn. For soft protruding coal seams, hole making during the withdrawal process is suitable for permeability enhancement. For medium-hard protruding coal seams, either retreating slot cutting or forward slot cutting can be used for permeability enhancement.

[0022] Furthermore, the hollow high-low pressure conversion valve includes an outer valve tube, an inner valve tube and a high-low pressure conversion assembly, the outer valve tube and the inner valve tube are coaxially installed, and the high-low pressure conversion assembly is installed in a flow supply channel formed between the outer valve tube and the inner valve tube; two spiral ribs are arranged on the outer circle of the outer valve tube; two radial water jet nozzles or two oblique water jet nozzles are arranged on the two spiral ribs of the outer valve tube; male buckles and female buckles are respectively arranged at both ends of the outer valve tube, the male buckle of the outer valve tube is connected to the transition drill rod, and the female buckle of the outer valve tube is connected to the sieve hole drill rod; a seal is installed on the outer side surface of the inner valve tube close to one end of the transition drill rod.

[0023] Furthermore, the high-low pressure conversion assembly includes a sliding valve core, a spring, a front support, a rear support and a fixing pin; a sliding valve core is installed between the front support and the rear support, a spring is installed between the sliding valve core and the valve inner tube, and the front support and the rear support are fixed to the valve outer tube through fixing pins; when working, both ends of the spring are in contact with the sliding valve core and the rear support. The hollow high-low pressure conversion valve is an independent hydraulic cavitation and slitting device used in conjunction with the internal slag removal screen hole drilling tool. It is installed and used when cavitation and slitting are needed for permeability enhancement, and can be omitted when hydraulic permeability enhancement is not needed. The hollow high-low pressure conversion valve has three working positions, namely, the low-pressure drilling position, the high-pressure cavitation position, and the drilling stop and locking position.

[0024] Other instructions for the shield pressure relief drill tool: At the drill bit drilling position of the shield pressure relief drill tool for the protruding coal seam, a cable-free directional screw drill tool can be used to replace the conventional drill bit to achieve shield pressure relief cable-free directional drilling, which is also within the protection scope of the present invention.

[0025] The out-of-hole closed slag discharge system used in conjunction with the protruding coal seam shield and pressure relief drill tool comprises a sliding closed pipe installed in the inner cavity of the screen hole drill pipe outside the hole, a closed hole and pipe moving device installed at the hole mouth, and a hollow slag discharge water (wind) tail connected to the tail of the protruding coal seam shield and pressure relief drill tool.

[0026] Furthermore, the sliding closed tube adopts a lightweight, wear-resistant, and abrasion-reducing thin-walled pipe, the outer diameter of the sliding closed tube is equal to or less than the inner diameter of the inner tube of the sieve hole drill rod, the length of the sliding closed tube is equal to the sum of the maximum length of the exposed sieve hole drill rod outside the hole and the length of the sealing hole pipe transfer device, and the sliding closed tube is installed in the inner tube of the sieve hole drill rod outside the closed hole and the covered section of the sealing hole pipe transfer device, and is used to close the slag discharge sieve hole, so that the water, coal slag and gas in the inner slag discharge channel are discharged from the inner cavity of the hollow slag discharge water (wind) tail at the tail of the sieve hole drill rod. If there is no sliding closed tube, water and gas will leak out of the slag discharge sieve hole, the inner slag discharge channel of the exposed drill rod will lose the slag discharge power, the inner slag discharge channel will be blocked, and the coal slag will be difficult to discharge from the slag discharge pipe at the rear end of the hollow slag discharge water (wind) tail.

[0027] Furthermore, the hole sealing and pipe moving device comprises a hole sealing bag, a double-layer tube, an air injection hole sealing interface, an air pressure pipe moving interface and a dustproof component; the double-layer tube comprises an outer tube and an inner tube coaxially sleeved, one end of the inner tube exposed from the drilling hole extends out of the outer tube and cooperates with the sleeve dustproof component, the hole sealing bag is fixed on the outer circle of the outer tube and is connected to the air injection hole sealing interface through a pipeline, so as to achieve the sealing of the hole in the expansion section;

[0028] A closed circular ring support and a support block are respectively installed between the two ends of the inner hole of the outer tube and the inner tube, the closed circular ring support is installed at one end close to the dustproof component, and the support block is installed at the end away from the dustproof component. An annular channel is formed between the inner hole of the outer tube and the inner tube, and an air inlet is also opened through the inner tube, and the air inlet is opened on the side of the support block facing away from the closed circular ring support;

[0029] The interface of the compressed air displacement pipe is connected to the annular channel of the double-layer pipe. By supplying high-pressure airflow to the annular channel of the double-layer pipe, the high-pressure airflow enters the inner hole of the inner pipe through the air inlet, and then enters the inner tube of the sieve hole drill rod through the slag discharge sieve hole. The high-pressure airflow drives the sliding closed tube to move toward the inner tube of the newly installed sieve hole drill rod to achieve the internal closure of the exposed sieve hole; copper ring support sleeves are inlaid and installed at both ends of the inner hole of the inner pipe. The function of the copper ring support sleeve is to prevent friction sparks between the double-layer pipe and the drill rod. When a large-angle downward hole is used for construction, a method of increasing the friction resistance of the sliding closed tube should be adopted to prevent the sliding inner closure from sliding downward when drilling and installing the drill rod. For large-angle downward drilling, the method of using high-pressure airflow to drive the sliding closed tube may fail. In this case, it is necessary to use manual pulling to move the sliding closed tube.

[0030] Furthermore, the dustproof assembly includes a cylinder and a dustproof brush installed in the cylinder, one end of the inner hole of the cylinder is installed at the outer end of the inner tube extending out of the outer tube, and the other end of the inner hole of the cylinder is installed with a dustproof brush. The function of the dustproof assembly is to reduce the dust at the orifice. When a shield pressure relief drill is used, the orifice is not used as a slag outlet, but a very small amount of coal slag will be discharged from the dustproof assembly to the outside of the hole, and most of the coal slag will be discharged from the hollow slag water (wind) tail of the drill tail.

[0031] Furthermore, the hollow slag water (wind) tail is connected to the female buckle of the sieve hole drill rod. When wind drilling, a lightweight hollow slag wind tail is used; when high-pressure water jet cavitation and cutting, a heavier hollow slag water tail with high-pressure sealing characteristics is used.

[0032] Furthermore, the hollow slag discharge water tail and the hollow slag discharge air tail both include an outer tube, an inner sleeve, a shell and a flow supply port. The outer tube is coaxially installed with the inner sleeve, and the rear ends of the outer tube and the inner sleeve are tightly sealed and installed as a whole through the shell. A flow supply channel is formed between the front end outer tube and the inner sleeve, the inner hole of the inner sleeve is a slag discharge channel, a flow supply port connected to the flow supply channel is provided on the outside of the shell, and a slag discharge port connected to the slag discharge channel is provided at the rear end of the shell.

[0033] The beneficial effects of the present invention are:

[0034] 1. Aiming at the problem of difficulty in processing the slag discharge screen hole, the present invention introduces a conical hole plate matching the slag discharge screen hole for the first time, avoiding the problem of difficulty in processing the inverted cone screen hole and the inverted step screen hole, not only ensuring the slag discharge effect of the slag discharge screen hole, but also improving the processing efficiency of the slag discharge screen hole and reducing the processing cost.

[0035] 2. In order to solve the problem of how the coal slag produced by the drill bit enters the internal slag discharge channel, the present invention designs a transition drill rod with a deep groove structure and a dense sieve hole structure, and designs a plug-in drill bit matching the transition drill rod, and provides a technical solution for the drill bit coal slag to quickly and efficiently enter the internal slag discharge channel of the drill tool.

[0036] 3. The present invention designs a hollow high-low pressure conversion valve with a central internal slag discharge function for the hollow internal slag discharge structure of the shield pressure relief drill, so that the shield pressure relief drill can implement the high-pressure water jet cavitation or slitting permeability enhancement function.

[0037] 4. The present invention is directed to a shield-protected pressure-relief screen hole drill bit that uses the central circular hole of the drill bit as an internal slag discharge channel, and proposes an out-of-hole closed slag discharge system that includes a hole sealing and pipe moving device, a sliding closed pipe, and a hollow slag discharge water (wind) tail. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 This is the overall connection diagram of the shield pressure relief drilling tool for the protruding coal seam of the present invention;

[0039] Figure 2 It is a structural diagram of the screen hole drill rod of the present invention;

[0040] Figure 3 Diagram of the tapered hole strip used for the screen hole drill rod of the present invention;

[0041] Figure 4 A diagram showing the sealing connection between the sieve hole drill rod and the sieve hole drill rod of the present invention;

[0042] Figure 5 It is a structural diagram of the transition drill rod of the present invention;

[0043] Figure 6 This is a structural diagram of the blind hole inner tube used in the transition drill rod of the present invention;

[0044] Figure 7 This is a diagram showing the connection between the transition drill rod and the screen hole drill rod of the present invention;

[0045] Figure 8 This is a structural diagram of the plug-in drill bit of the present invention;

[0046] Fig. 9 This is a diagram showing the connection between the transition drill rod and the plug-in drill bit of the present invention;

[0047] Fig.10 This is a connection diagram of the hollow high-low pressure conversion valve of the present invention, the sieve hole drill rod and the transition drill rod;

[0048] Fig.11 This is a structural diagram of the hollow high-low pressure conversion valve of the present invention;

[0049] Fig.12 This is a working position diagram of the hollow high-low pressure conversion valve of the present invention;

[0050] Fig.13 It is the overall configuration diagram of the shield pressure relief drill tool and the out-of-hole closed slag discharge system of the present invention;

[0051] Fig.14 It is a structural diagram of the sliding closed tube of the present invention;

[0052] Fig.15 It is a structural diagram of the hole sealing and pipe moving device of the present invention;

[0053] Fig.16 It is a schematic diagram of the structure of the hollow slag water (wind) tail in the present invention. DETAILED DESCRIPTION

[0054] The present invention is further described below in conjunction with the accompanying drawings.

[0055] like Figure 1 The present invention discloses an overall connection diagram of a protruding coal seam shield and pressure relief drill tool, which comprises a plurality of sieve hole drill rods 1, a transition drill rod 2 and a plug-in drill bit 3 which are sequentially connected from back to front, wherein the sieve hole drill rods 1 are connected to each other by threaded connection, the sieve hole drill rods 1 and the transition drill rods 2 are connected to each other by threaded connection, and the transition drill rods 2 and the plug-in drill bit 3 are connected by plug-in connection.

[0056] Figure 2 The structural diagram of the sieve hole drill rod of the present invention is shown in FIG. The sieve hole drill rod 1 is composed of an outer tube 11, an inner tube 12 and a tapered hole plate 13. The outer tube 11 is a special-shaped outer tube 11. The outer surface of the special-shaped outer tube 11 is provided with an axial groove. The inner hole of the special-shaped outer tube 11 is provided with an axial protrusion corresponding to the position of the axial groove. The number of the axial grooves and the axial protrusions is two or three. Figure 2 (a) is a structural diagram of a sieve drill rod with two axial grooves. Figure 2(b) is a structural diagram of a sieve hole drill rod with three axial grooves. The two ends of the special-shaped outer tube 11 of the sieve hole drill rod 1 are converted into thick-walled round tubes by extrusion molding or friction welding and jointing. The male and female buckles of the sieve hole drill rod are processed on the thick-walled round tube for connecting the two drill rods. A spiral groove 18 is arranged on the outer arc surface of the special-shaped outer tube 11. The size and shape of the spiral groove 18 are not restricted. The function of the spiral groove 18 is to increase the pressure relief function and cooling function of the sieve hole drill rod. The inner tube 12 is a round tube. The center hole of the inner tube 12 is the inner slag discharge channel 16 of the sieve hole drill rod. A sealing ring 17 is installed at one end of the inner tube 12 for sealing between the two sieve hole drill rods. After the special-shaped outer tube 11 and the inner tube 12 are coaxially embedded and sealed, a plurality of slag discharge sieve holes 15 connected with the inner slag discharge channel 16 are arranged in the axial groove of the special-shaped outer tube 11.

[0057] The tapered hole strip 13 is fixed in the axial groove by brazing or spot welding. The tapered hole strip 13 is provided with the same number of tapered holes 131 as the slag discharge screen holes 15 in the axial groove, and the tapered holes 131 are arranged one-to-one and coaxially with the slag discharge screen holes 15. The sieve hole drill rod 1 has a flow supply channel 14 and an internal slag discharge channel 16 in the axial direction, and the flow supply direction is opposite to the slag discharge direction; the sieve hole drill rod 1 has a large number of slag discharge screen holes 15 in the radial direction, and the slag discharge screen holes 15 are connected to the internal slag discharge channel 16 but not to the flow supply channel 14. Therefore, it is required that the special-shaped outer tube 11 and the inner tube 12 need to be sealed in an embedded manner, and the contact surface of the special-shaped outer tube 11 and the inner tube 12 is kept sealed by shrink fitting, impregnation sealing and other processes.

[0058] Figure 3 The figure is a tapered hole plate used for the sieve hole drill rod of the present invention. The tapered hole plate 13 is a wear-resistant thin-walled plate. The tapered hole plate 13 is provided with the same number of tapered holes 131 as the slag discharge screen holes 15 in the axial groove of the sieve hole drill rod. The diameter of the slag discharge screen holes 15 of the sieve hole drill rod 1 is less than one-third of the diameter of the inner hole of the inner tube 12. The small diameter of the tapered hole 131 on the tapered hole plate 13 of the sieve hole drill rod 1 is less than the diameter of the slag discharge screen holes 15, and the large diameter of the tapered hole 131 is equal to the diameter of the slag discharge screen holes 15. The thickness of the tapered hole plate 13 is less than the difference between the depth of the axial groove of the special-shaped outer tube 11 and the depth of the spiral groove. After welding the tapered hole plate 13, the tapered hole plate 13 is still at the lowest position on the outer surface of the sieve hole drill rod to facilitate slag gathering and discharge. The small diameter of the tapered hole of the tapered hole plate 13 is outside and the large diameter is inside, and the drilling slag can smoothly pass through the tapered hole 131 and the slag discharge screen holes 15. The protection scope of the present invention also includes adopting other methods such as screen hole extrusion method, screen hole surfacing method, single-piece tapered hole welding method, water jet or laser reverse tapered hole cutting method, reverse tapered hole countersinking method, etc. to make the slag inlet diameter of the slag discharge screen hole 15 smaller than the slag outlet diameter.

[0059] In order to increase the rubbing and crushing function of the conical hole slats 13 facing the coal surface, methods such as indentation and spraying of wear-resistant particles can be implemented on the conical hole slats 13. The conical hole slats 13 can also be made of wear-resistant steel or powder metallurgy materials. The conical hole 131 can be made of stamped conical holes or drilled conical holes. Similar related auxiliary technologies are also within the protection scope of the present invention. The radial straight hole slag discharge screen hole 15 is the most convenient to process. If the slag discharge screen hole 15 is processed into an inclined hole, it is more convenient to discharge the slag from the screen hole slag 15, which is also within the protection scope of the present invention. When the diameter of the radial straight hole slag discharge screen hole 15 is about 1.5 times the depth of the slag discharge screen hole 15, the slag discharge screen hole 15 is not easy to be blocked. When the geometric dimensions, strength and other factors of the screen hole drill rod 1 permit, the slag discharge screen hole 15 with a diameter greater than the depth can be designed. In this case, the conical hole slats 13 can be eliminated.

[0060] For extremely soft protruding coal seams, the spiral groove 18 may not be provided on the outer arc surface of the special-shaped outer tube 11. Although the pressure relief function of the drill pipe is weakened, the shield function of the drill pipe is increased, which is also within the protection scope of the present invention. The surface of the sieve hole drill pipe 1 is sprayed with wear-resistant materials to increase the wear resistance and service life of the drill pipe, which is also within the protection scope of the present invention.

[0061] The spiral groove 18 may not be arranged on the outer arc of the special-shaped outer tube 11 of the sieve hole drill rod 1, and the axial groove may be changed into a large-pitch spiral groove by the hot twisting method, and the corresponding axial protrusion may be changed into a large-pitch spiral protrusion, and the corresponding tapered hole plate 13 may adopt a large-pitch tapered hole plate, and the matching mode of the special-shaped outer tube 11 and the inner tube 12 remains unchanged. In this embodiment, the sieve hole drill rod 1 comprises an outer tube 11 and an inner tube 12 which are plug-in matched, and the inner tube 12 is a round tube, and the center hole of the inner tube 12 is an inner slag discharge channel 16 of the sieve hole drill rod 1; the outer tube 11 is a hot-twisted special-shaped outer tube 11 formed by a hot twisting method under a constrained state, and a large-pitch spiral groove is formed on the outer surface of the hot-twisted special-shaped outer tube 11, and a large-pitch arc surface protrusion corresponding to the large-pitch spiral groove is formed on the inner hole of the hot-twisted special-shaped outer tube 11, and the large-pitch arc surface protrusion of the inner hole of the hot-twisted special-shaped outer tube 11 is matched with the outer circle of the inner tube 12 and installed, and The inner tube 12 is supported so that the outer tube 11 and the inner tube 12 remain coaxial, and the number of large pitch spiral grooves and large pitch cambered protrusions is two or three; a large pitch tapered hole strip is installed in the large pitch spiral groove, and a plurality of slag discharge screen holes 15 connected to the inner slag discharge channel 16 are arranged in the large pitch spiral groove of the hot twisted special-shaped outer tube 11; the large pitch tapered hole strip is provided with the same number of tapered holes as the slag discharge screen holes 15 in the large pitch spiral groove, and the tapered holes are coaxially matched with the slag discharge screen holes 15 one by one; the thickness of the large pitch tapered hole strip is less than the depth of the large pitch spiral groove.

[0062] Figure 4The sieve hole drill rod and the sieve hole drill rod sealing connection diagram of the present invention are connected by a threaded connection with a seal between the sieve hole drill rods 1 and the inner tubes 12 of the sieve hole drill rods 1 and the inner tubes 12 are connected by a plug-in sealing connection or a lap-joint sealing connection. Figure 4 (a) is a plug-in sealing structure, in which an O-ring 17 is used for plug-in sealing, and the rear end of the inner tube 12 of the sieve hole drill rod 1 is expanded, and the inner diameter of the expanded opening is equal to the diameter of the inner tube 12; Figure 4 (b) is a lap seal structure. When lap seal is performed, the diameters of the inner tube 12 of the sieve hole drill rod 1 are the same at both ends. The lap seal ring 17 is used for lap seal. In order to improve the strength of the lap seal ring 17, measures such as wrapping a steel ring in the wall thickness of the lap seal ring 17 can be taken; the flow supply channel 14 at the threaded connection between the sieve hole drill rod 1 and the sieve hole drill rod 1 is an annular flow supply channel. The outer arc of the female buckle of the sieve hole drill rod 1 can be added with a spiral groove, or it can be added without a spiral groove. Adding a spiral groove is conducive to cooling the threaded part of the drill rod, but it weakens the strength of the female buckle.

[0063] Figure 5 This is a structural diagram of the transition drill rod of the present invention. The transition drill rod 2 is composed of a deep groove special-shaped outer tube 21, a blind hole inner tube 22 and dense tapered hole strips 23. The outer surface of the deep groove special-shaped outer tube 21 is provided with an axial groove, and the inner hole of the deep groove special-shaped outer tube 21 is provided with an axial protrusion corresponding to the axial groove. The number of the axial grooves and the axial protrusions is 3 or 4.

[0064] One end of the deep groove shaped outer tube 21 of the transition drill rod 2 is converted into a thick wall round tube by extrusion molding or friction welding and jointing, and a female buckle connected to the male buckle of the sieve hole drill rod 1 is processed on the thick wall round tube, and the other end of the deep groove shaped outer tube 21 is provided with a radial top screw hole.

[0065] The blind hole inner tube 22 is a round tube with a conical plug 221 at one end, and the central hole of the blind hole inner tube 22 is the inner slag discharge channel 16 of the transition drill pipe 2; after the deep groove special-shaped outer tube 21 is coaxially embedded and sealed with the blind hole inner tube 22, a plurality of slag discharge screen holes 15 connected to the inner slag discharge channel 16 are processed in the axial groove of the deep groove special-shaped outer tube 21; the structure and shape of the dense cone hole plate 23 are similar to the structure and shape of the cone hole plate 13, and the dense cone hole plate 23 is provided with the same number of cone holes as the slag discharge screen holes in the axial groove of the deep groove special-shaped outer tube 21, and the dense cone hole plate is fixed in the axial groove by brazing or spot welding, and the cone holes are one-to-one coaxially compared with the slag discharge screen holes. The sieve hole density of the transition drill pipe 2 is greater than that of the sieve hole drill pipe 1, and the number of slag discharge screen holes is greater. The installation method of the dense cone hole plate 23 of the transition drill pipe 2 is the same as the installation method of the cone hole plate 13 of the sieve hole drill pipe 1.

[0066] Figure 6The blind hole inner tube structure diagram used for the transition drill rod of the present invention, the blind hole inner tube 22 is a round tube with a conical plug 221 at one end, and the other end of the blind hole inner tube 22 is a flared round tube, which is used for the sealed connection between the inner tube 12 of the sieve hole drill rod 1 and the blind hole inner tube 22 of the transition drill rod 2, the outer diameter of the blind hole inner tube 22 of the transition drill rod 2 is smaller than the outer diameter of the inner tube 12 of the sieve hole drill rod 1, and correspondingly, the depth of the axial groove of the deep groove special-shaped outer tube 21 of the transition drill rod 2 is greater than the depth of the axial groove of the special-shaped outer tube 11 of the sieve hole drill rod 1.

[0067] The transition drill rod 2 is a special sieve drill rod with a stronger slag discharge capability. The axial grooves guiding the drill bits are deeper, the number of axial grooves is greater, and the density of the slag discharge sieve holes 15 is greater. The transition drill rod 2 is used in conjunction with the plug-in drill bit 3. The coal slag produced by the drill bit first enters the axial grooves and then enters the inner slag discharge channel 16 through the dense slag discharge sieve holes. For medium-hard coal seams, the outer surface of the deep groove special-shaped outer tube of the transition drill rod can also be provided with spiral grooves to improve the slag crushing, slag gathering and pressure relief capabilities of the transition drill rod.

[0068] Figure 7 The figure is a connection diagram of the transition drill rod and the sieve hole drill rod. The connection between the transition drill rod 2 and the sieve hole drill rod 1 adopts a threaded connection with a seal. The connection between the inner tube 12 of the sieve hole drill rod 1 and the blind hole inner tube 22 of the transition drill rod 2 adopts a plug-in seal connection or a lap seal connection. In this embodiment, it is a plug-in seal connection. The flow supply channel at the threaded connection between the transition drill rod 2 and the sieve hole drill rod 1 is an annular flow supply channel. In order to increase the cross-sectional area of ​​the flow supply channel of the transition drill rod 2, the outer diameter of the blind hole inner tube 22 of the transition drill rod 2 is smaller than the outer diameter of the inner tube 12 of the sieve hole drill rod 1.

[0069] Figure 8 It is a structural diagram of the plug-in drill bit of the present invention, wherein one end of the plug-in drill bit 3 that cooperates with the deep groove special-shaped outer tube 21 is provided with a drill shank 31, and the other end of the plug-in drill bit 3 is provided with a cutting portion and a plurality of flow supply holes; the outer shape and size of the drill shank 31 are the same as the inner hole shape and size of the deep groove special-shaped outer tube 21 of the transition drill rod 2. During installation, the drill shank 21 is inserted into the inner hole of the deep groove special-shaped outer tube 21, and cooperates with the radial top screw hole that fixes the deep groove special-shaped outer tube 21 through the top screw, so that the plug-in drill bit 3 and the transition drill rod 2 are plugged in and fastened.

[0070] Fig. 9The plug-in drill bit and the transition drill rod connection structure diagram of the present invention, the drill shank 31 of the plug-in drill bit 3 is inserted into the inner hole of the deep groove special-shaped outer tube 21 of the transition drill rod 2, and fixed with a top screw 33, so that the plug-in drill bit 3 and the transition drill rod 2 are plug-in connected, and the flow supply channel at the plug-in point of the transition drill rod 2 and the plug-in drill bit 3 is changed from multiple circumferential axial flow supply channels to a central circular flow supply channel. The reason why the drill bit adopts a plug-in connection instead of a threaded connection is that the plug-in connection can use the groove of the special-shaped drill shank to axially dock with the axial groove of the transition drill rod, which can reduce the loss of slag removal power and enable the coal slag drilled into the internal slag removal channel quickly and efficiently.

[0071] Fig.10 This is a connection diagram of the hollow high-low pressure conversion valve, the screen hole drill rod and the transition drill rod of the present invention. A hollow high-low pressure conversion valve 4 can be installed between the screen hole drill rod 1 and the transition drill rod 2, so that the drill tool has the function of high-pressure water jet cavitation and slitting when withdrawing the drill. For soft protruding coal seams, it is advisable to use cavitation and permeability enhancement during the withdrawal process. For medium-hard protruding coal seams, both retreat-type slitting and permeability enhancement can be used. For forward-type slitting and permeability enhancement, it is also possible to use backward-type slitting and permeability enhancement.

[0072] Fig.11 The structure diagram of the hollow high-low pressure conversion valve of the present invention is shown in FIG. Fig.11 As shown in (a), the hollow high-low pressure conversion valve 4 is composed of a valve outer tube 41, a valve inner tube 42 and a high-low pressure conversion assembly (features 431-435); the valve outer tube 41 and the valve inner tube 42 are coaxially mounted, and the high-low pressure conversion assembly is installed in the flow supply channel formed between the valve outer tube 41 and the valve inner tube 42;

[0073] Two spiral ribs are arranged on the outer circle of the valve outer tube 41, and two radial or oblique water jet nozzles 44 are arranged on the two spiral ribs of the valve outer tube 41; male buckles and female buckles are arranged at both ends of the valve outer tube 41, and the male buckle of the valve outer tube 41 is used to connect with the transition drill rod 2, and the female buckle of the valve outer tube 41 is used to connect with the sieve hole drill rod 1; a seal 45 is installed on the outer surface of the end of the valve inner tube 42 close to the transition drill rod 2, and the central hole of the valve inner tube 42 is also a section of internal slag discharge channel. Fig.11As shown in (b), the high-low pressure conversion assembly is installed in the flow channel between the valve outer tube 41 and the valve inner tube 42. The high-low pressure conversion assembly consists of a sliding valve core 431, a spring 432, a front support 433, a rear support 434 and a fixing pin 435; the sliding valve core 431 is installed between the front support 433 and the rear support 434, and the spring 432 is installed between the sliding valve core 431 and the valve inner tube 42. The front support 433 and the rear support 434 are connected to the valve outer tube 41 through the fixing pin 435; when working, the two ends of the spring 432 are in contact with the sliding valve core 431 and the rear support 434. The hollow high-low pressure conversion valve 4 is an independent hydraulic cavitation and slitting device used in conjunction with the internal slag removal screen hole drilling tool. It is installed and used when cavitation and slitting are needed for permeability enhancement, and can be omitted when hydraulic permeability enhancement is not required.

[0074] The hollow high-low pressure conversion valve 4 has three positions, namely, the low-pressure drilling position, the high-pressure hole making position, and the stop drilling locking position.

[0075] Fig.12 This is a working position diagram of the hollow high-low pressure conversion valve of the present invention. The sliding valve core 431 of the hollow high-low pressure conversion valve 4 has three working positions. Fig.12 (a) shows the stop drilling lockout position, which is the position status when drilling is stopped for loading and unloading drill pipes, etc. Fig.12 (b) shows a low-pressure drilling station, where all low-pressure fluid is supplied to the front plug-in drill bit 3; Fig.12 (c) shows a water jet cutting or punching station, where high-pressure fluid is supplied to the jet nozzle 44, and a small amount of fluid is supplied to the plug-in drill bit 3 through leakage or micro-pore leakage to cool the drill bit. There are many ways to supply a small amount of water flow to the drill bit under high pressure. Generally, engineers can make slight changes to the sliding valve core and the support as needed, which is also within the scope of protection of the present invention.

[0076] During the implementation of the present invention, the water jet nozzle 44 of the high-low pressure conversion valve 4 can be replaced. When a small-diameter nozzle is used, hydraulic slitting of medium-hard coal can be achieved, and when a large-diameter nozzle is used, hydraulic punching of soft coal seams can be achieved. Two groups of water jet nozzles 44 can also be set on the spiral rib, one group is two radial slitting nozzles, and the other group is two radial or oblique punching nozzles. The above three-station high-low pressure conversion assembly is designed as a four-station high-low pressure conversion assembly, namely the locking station, low-pressure drilling station, medium-pressure punching station and high-pressure slitting station, which are also within the protection scope of the present invention. However, due to the influence of the medium pressure in the hole outside the valve outer tube, the switching accuracy between the punching station and the slitting station will be reduced, the difficulty of spring selection will increase, and the reliability will be reduced. If the hollow high-low pressure conversion valve 4 is designed with four stations, it is also within the protection scope of the present invention.

[0077] Other instructions for the shield and pressure relief drill tool for the protruding coal seam: At the drill bit drilling position of the shield and pressure relief drill tool for the protruding coal seam, a cable-free directional screw drill tool can be used to replace the conventional drill bit to achieve shield and pressure relief cable-free directional drilling, which is also within the protection scope of the present invention.

[0078] The closed slag discharge system outside the hole used in conjunction with the shield pressure relief drilling tool for the protruding coal seam is described as follows:

[0079] The closed slag discharge system outside the hole comprises a sliding closed pipe 5 placed in the inner cavity of the sieve hole drill rod 1 outside the hole, a closed hole pipe moving device 6 installed at the hole mouth and a hollow slag discharge water (wind) tail 7 connected to the tail of the drill rod.

[0080] Fig.13 The figure is a general configuration diagram of the shield pressure relief drill tool and the closed slag discharge system outside the hole. The sealing and pipe-shifting device 6 is installed at the borehole mouth to block the external slag discharge channel at the borehole mouth, so that the drill slag and air flow are discharged outward from the internal slag discharge channel 16 of the sieve hole drill rod 1; the sieve hole drill rod 1 passes through the central hole of the sealing and pipe-shifting device 6, and the front end of the sieve hole drill rod 1 is connected to the transition drill rod 2 and the plug-in drill bit 3; the hollow slag discharge water (wind) tail 7 is connected to the tail of the last sieve hole drill rod 1, and pressure air flow or water flow is provided for drilling through the air inlet; a sliding closed pipe 5 is placed in the inner cavity of the sieve hole drill rod 1 outside the hole to seal the slag discharge sieve hole 15 of the sieve hole drill rod 1 outside the hole and the section covered by the sealing and pipe-shifting device 6, forcing the water-coal slag and gas in the internal slag discharge channel 16 to be discharged from the inner cavity of the hollow slag discharge water (wind) tail 7 at the tail of the sieve hole drill rod 1.

[0081] Fig.14 The sliding closed pipe structure diagram is shown in FIG. 5 . The sliding closed pipe 5 is a lightweight, wear-resistant, and abrasion-reducing thin-walled pipe. The outer diameter of the sliding closed pipe 5 is equal to or less than the inner diameter of the inner pipe 12 of the sieve hole drill pipe. The length of the sliding closed pipe 5 is equal to the sum of the maximum length of the exposed sieve hole drill pipe 1 outside the hole and the length of the sealing hole pipe transfer device 6. The sliding closed pipe 5 is used to seal the slag discharge sieve hole 15 of the sieve hole drill pipe 1 outside the hole and the section covered by the sealing hole pipe transfer device 6, forcing the water coal slag and gas in the inner slag discharge channel 16 to be discharged from the inner cavity of the hollow slag discharge water (wind) tail 7 at the tail of the sieve hole drill pipe 1. If there is no sliding closed pipe 5, water and gas will leak out of the slag discharge sieve hole 15, the inner slag discharge channel 16 of the exposed drill pipe will lose the slag discharge power, and the inner slag discharge channel 16 will be blocked, and the coal slag will be difficult to be discharged from the slag discharge pipe at the rear end of the hollow slag discharge water (wind) tail 7.

[0082] Fig.15The structural diagram of the sealing and pipe-moving device 6 is composed of a sealing bag 61, a double-layer tube 62, an air-injection sealing interface 63, a compressed air pipe-moving interface 64 and a dust-proof component 65; the sealing bag 61 is fixed on the outer circle of the double-layer tube 62 and connected to the air-injection sealing interface 63 to achieve the sealing of the hole in the expansion section; the compressed air pipe-moving interface 64 is connected to the annular channel of the double-layer tube 62, and a high-pressure airflow is supplied to the annular channel of the double-layer tube 62, and the high-pressure airflow drives the sliding sealing tube to move toward the inner tube 12 of the newly installed sieve hole drill rod 1, so as to achieve the internal sealing of the exposed sieve hole of the newly installed drill rod. A closed circular ring support is installed between the double-layer tubes 62 at one end close to the dust-proof component, and a support block 67 support is installed between the double-layer tubes 62 at one end away from the dust-proof component; copper ring support sleeves 66 are inlaid at both ends of the inner hole of the double-layer tube 62, and the function of the copper ring support sleeve 66 is to prevent friction sparks from being generated between the inner hole of the double-layer tube 62 and the drill rod. When a large-angle downward hole is used for construction, a method of increasing the friction resistance of the sliding closed pipe 5 should be adopted to prevent the sliding closed pipe from sliding downward when drilling and installing the drill rod. For large-angle downward drilling, the method of using compressed air to drive the sliding closed pipe may fail. In this case, it is necessary to use manual pulling to move the sliding closed pipe 5.

[0083] The dustproof assembly 65 is composed of a cylinder 651 and a dustproof brush 652 installed in the cylinder. One end of the inner hole of the cylinder 651 is installed on the outer end of the inner tube extending out of the outer tube on the double-layer tube 62, and the dustproof brush 652 is installed at the other end of the inner hole of the cylinder. The function of the dustproof assembly 65 is to reduce the dust at the orifice. When the shield pressure relief drill is used, the orifice is not used as a slag discharge outlet, but a very small amount of coal slag will be discharged from the dustproof assembly 65 to the outside of the hole, and most of the coal slag will be discharged from the hollow slag water (wind) tail 7 of the drill tail.

[0084] Fig.16 The hollow slag water (wind) tail 7 is a structural diagram of the hollow slag water (wind) tail. The hollow slag water (wind) tail 7 is mainly composed of an outer tube 71, an inner sleeve 72, a shell 73, and a flow port 74. The flow port 74 is used to provide wind flow and water flow. The outer tube 71 is coaxially assembled with the inner sleeve 72. The rear ends of the outer tube 71 and the inner sleeve 72 are tightly sealed and installed as a whole through the shell 73. A flow channel 14 is provided between the front end of the outer tube 71 and the inner sleeve 72. The inner sleeve 72 is provided with a flow channel 14. The hole is a slag discharge channel 16, and the drill slag is discharged from the slag discharge port 76 through the slag discharge channel 16; a male buckle 75 is provided at one end of the outer tube 71, and the male buckle 75 is connected to the female buckle of the sieve hole drill rod 1, the outer tube 71 and the inner sleeve 72 are fixed as a whole, and the outer tube 71 and the shell 73 can rotate relatively; a lightweight hollow slag discharge wind tail 7 is used for wind drilling, and a heavy hollow slag discharge water tail 7 with high-pressure sealing characteristics is used for high-pressure water jet cavitation and cutting.

[0085] This embodiment does not impose any formal limitation on the shape, material, structure, etc. of the present invention. Any simple modification, equivalent change and modification made to the above embodiment based on the technical essence of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0086] In the description of the present invention, it is necessary to understand that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the protection content of the present invention.

[0087] If the words "first", "second", etc. are used in this document to limit components, those skilled in the art should know that the use of "first" and "second" is only to facilitate the description of the present invention and simplify the description. Unless otherwise stated, the above words have no special meaning.

[0088] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein, but these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A shield pressure relief drill for a protruding coal seam, characterized in that: It comprises a plurality of sieve hole drill rods, a transition drill rod and a plug-in drill bit connected in sequence from the back to the front, wherein the sieve hole drill rods are connected with each other by thread, the sieve hole drill rods are connected with the transition drill rod by thread, and the transition drill rod is connected with the plug-in drill bit by plug-in; The transition drill pipe is composed of a deep groove special-shaped outer tube, a blind hole inner tube and dense tapered hole strips, the outer surface of the deep groove special-shaped outer tube is provided with an axial groove, the inner hole of the deep groove special-shaped outer tube is provided with an axial protrusion corresponding to the position of the axial groove, and the number of the axial grooves and axial protrusions is three or four; The blind hole inner tube is a round tube with a conical plug at one end, and the central hole of the blind hole inner tube is an inner slag discharge channel of the transition drill rod; The deep groove special-shaped outer tube is embedded and sealed with the blind hole inner tube, and a plurality of slag discharge sieve holes connected with the inner slag discharge channel are provided in the axial groove of the deep groove special-shaped outer tube; The dense cone hole plate strip is installed in the axial groove, and the dense cone hole plate strip is provided with cone holes with the same number as the slag discharge screen holes in the axial groove, and the cone holes are coaxially matched with the slag discharge screen holes one by one.

2. The shield pressure relief drill tool for protruding coal seams according to claim 1 is characterized in that: The sieve hole drill rod comprises an outer tube, an inner tube and a tapered hole strip, the outer tube is a special-shaped outer tube, the outer surface of the special-shaped outer tube is provided with an axial groove, the inner hole of the special-shaped outer tube is provided with an axial protrusion corresponding to the position of the axial groove, and the number of the axial groove and the axial protrusion is two or three; the inner tube is a round tube, and the center hole of the inner tube is the inner slag discharge channel of the sieve hole drill rod; the special-shaped outer tube is embedded and sealed with the inner tube, the axial protrusion is installed in contact with the inner tube, and the tapered hole strip is installed in the axial groove; The axial groove of the special-shaped outer tube is provided with a plurality of slag discharge sieve holes connected with the inner slag discharge channel; the conical hole plate strip is provided with the same number of conical holes as the slag discharge sieve holes in the axial groove, and the conical holes are coaxially matched with the slag discharge sieve holes one by one.

3. The shield pressure relief drill tool for protruding coal seams according to claim 2 is characterized in that: The two ends of the special-shaped outer tube of the sieve hole drill rod are converted into thick-walled round tubes by extrusion molding or friction welding and jointing, and male buckles and female buckles for connecting adjacent special-shaped outer tubes are processed on the thick-walled round tubes; a spiral groove is arranged on the outer arc surface of the special-shaped outer tube.

4. The shield pressure relief drill tool for protruding coal seams according to claim 3 is characterized in that: The diameter of the slag sieve hole of the sieve hole drill rod is smaller than one-third of the diameter of the inner tube; the minor diameter of the tapered hole on the tapered hole strip is smaller than the diameter of the slag sieve hole, and the major diameter of the tapered hole on the tapered hole strip is equal to the diameter of the slag sieve hole; the thickness of the tapered hole strip is smaller than the difference between the depth of the axial groove of the special-shaped outer tube and the depth of the spiral groove.

5. The shield pressure relief drill tool for protruding coal seams according to claim 1, characterized in that: The sieve hole drill rod comprises an outer tube and an inner tube which are inserted and matched, the inner tube is a round tube, and the central hole of the inner tube is an inner slag discharge channel of the sieve hole drill rod; The outer tube is a hot-twisted special-shaped outer tube formed by a hot-twisting method under a constrained state, the outer surface of the hot-twisted special-shaped outer tube forms a large-pitch spiral groove, the inner hole of the hot-twisted special-shaped outer tube forms a large-pitch arc-surface protrusion corresponding to the large-pitch spiral groove, the large-pitch arc-surface protrusion of the inner hole of the hot-twisted special-shaped outer tube is installed in cooperation with the outer circle of the inner tube, and supports the inner tube so that the outer tube and the inner tube remain coaxial, the number of large-pitch spiral grooves and large-pitch arc-surface protrusions is two or three; large-pitch tapered hole strips are installed in the large-pitch spiral grooves, The large pitch spiral groove of the hot-twisted special-shaped outer tube is provided with a plurality of slag discharge screen holes connected with the internal slag discharge channel; the large pitch conical hole strip is provided with conical holes with the same number as the slag discharge screen holes in the large pitch spiral groove, and the conical holes are coaxially matched with the slag discharge screen holes one by one; the thickness of the large pitch conical hole strip is less than the depth of the large pitch spiral groove.

6. The shield pressure relief drill tool for protruding coal seams according to any one of claims 1 to 5, characterized in that: The sieve hole drill rods are connected by sealed threaded connections, the inner tubes of the sieve hole drill rods are connected by plug-in sealing connections or lap-sealed connections, and the flow supply channel at the threaded connection between the sieve hole drill rods is an annular flow supply channel.

7. The shield pressure relief drill tool for protruding coal seams according to claim 1, characterized in that: The outer diameter of the blind hole inner tube of the transition drill rod is smaller than the outer diameter of the inner tube of the sieve hole drill rod, the depth of the axial groove of the deep groove special-shaped outer tube of the transition drill rod is greater than the depth of the axial groove of the special-shaped outer tube of the sieve hole drill rod; the slag discharge sieve hole density of the transition drill rod is greater than the slag discharge sieve hole density of the sieve hole drill rod.

8. The shield pressure relief drill tool for protruding coal seams according to claim 1 or 7, characterized in that: One end of the deep groove shaped outer tube of the transition drill rod is converted into a thick-walled round tube by extrusion molding or friction welding and jointing, and a female buckle connected to the male buckle of the sieve hole drill rod is processed on the thick-walled round tube; the other end of the deep groove shaped outer tube of the transition drill rod is provided with a radial top screw hole.

9. The shield pressure relief drill tool for protruding coal seams according to claim 8, characterized in that: One end of the plug-in drill bit that cooperates with the deep groove special-shaped outer tube is provided with a drill handle, and the other end of the plug-in drill bit is provided with a cutting portion and a plurality of flow supply holes; The outer shape and size of the drill shank are the same as the inner hole shape and size of the deep groove special-shaped outer tube of the transition drill rod. During installation, the drill shank is inserted into the inner hole of the deep groove special-shaped outer tube, and cooperates with the radial top screw hole of the fixed deep groove special-shaped outer tube through the top screw, so that the plug-in drill bit and the transition drill rod can be plugged in and fastened.

10. The shield pressure relief drilling tool for protruding coal seams according to claim 9, characterized in that: A hollow high-low pressure conversion valve is also installed between the sieve hole drill rod and the transition drill rod, so that the drill tool has the function of high-pressure water jet cavitation or cutting when withdrawing the drill.

11. The shield pressure relief drilling tool for protruding coal seams according to claim 10, characterized in that: The hollow high-low pressure conversion valve comprises an outer valve tube, an inner valve tube and a high-low pressure conversion assembly, wherein the outer valve tube and the inner valve tube are coaxially mounted, and the high-low pressure conversion assembly is mounted in a flow supply channel formed between the outer valve tube and the inner valve tube; Two spiral ribs are arranged on the outer circle of the valve outer tube; two radial water jet nozzles or two oblique water jet nozzles are arranged on the two spiral ribs of the valve outer tube; male buckles and female buckles are respectively arranged at both ends of the valve outer tube, the male buckle of the valve outer tube is connected to the transition drill rod, and the female buckle of the valve outer tube is connected to the sieve hole drill rod; a seal is installed on the outer surface of one end of the valve inner tube close to the transition drill rod.

12. The protruding coal seam shield pressure relief drill tool according to claim 11, characterized in that: The high-low pressure conversion assembly includes a sliding valve core, a spring, a front support, a rear support and a fixing pin; the sliding valve core is installed between the front support and the rear support, a spring is installed between the sliding valve core and the valve inner tube, and the front support and the rear support are connected to the valve outer tube through the fixing pin; when working, the two ends of the spring are in contact and cooperate with the sliding valve core and the rear support.

13. An out-of-hole closed slag discharge system used in conjunction with the protruding coal seam shield pressure relief drill tool according to any one of claims 1 to 12, characterized in that: It comprises a sliding sealing pipe installed in the inner cavity of a screen hole drill pipe outside the hole, a sealing hole pipe moving device installed at the hole mouth and a hollow slag water tail or a hollow slag air tail connected to the tail of a shield pressure relief drill tool for a protruding coal seam.

14. The closed slag discharge system outside the hole according to claim 13, characterized in that: The sliding closed tube adopts lightweight, wear-resistant and abrasion-reducing thin-walled pipe. The outer diameter of the sliding closed tube is equal to or smaller than the inner diameter of the inner tube of the sieve hole drill rod. The length of the sliding closed tube is equal to the sum of the maximum length of the exposed sieve hole drill rod outside the hole and the length of the sealing hole pipe transfer device. The sliding closed tube is installed in the inner tube of the sieve hole drill rod outside the closed hole and the covered section of the sealing hole pipe transfer device, and is used to seal the slag discharge sieve hole, so that the water-coal slag gas in the internal slag discharge channel is discharged from the inner cavity of the hollow slag water tail or the hollow slag air tail at the tail of the sieve hole drill rod.

15. The closed slag discharge system outside the hole according to claim 14, characterized in that: The sealing and pipe-moving device comprises a sealing bag, a double-layer pipe, an air injection sealing interface, a compressed air pipe-moving interface and a dust-proof component; The double-layer tube comprises an outer tube and an inner tube coaxially sleeved, the end of the inner tube exposed from the drilled hole extends out of the outer tube and cooperates with the sleeved dust-proof component, the sealing bag is fixed on the outer circle of the outer tube and connected to the gas injection sealing interface through a pipeline; A closed circular ring support and a support block are respectively installed between the two ends of the inner hole of the outer tube and the inner tube, the closed circular ring support is installed at one end close to the dustproof component, and the support block is installed at the end away from the dustproof component. An annular channel is formed between the inner hole of the outer tube and the inner tube, and an air inlet is also opened through the inner tube, and the air inlet is opened on the side of the support block facing away from the closed circular ring support; The pressure air moving pipe interface is connected to the annular channel of the double-layer pipe, and the high-pressure airflow is supplied to the annular channel of the double-layer pipe. The high-pressure airflow enters the inner hole of the inner layer pipe through the air inlet, and then enters the inner tube of the sieve hole drill rod through the slag discharge sieve hole. The high-pressure airflow drives the sliding sealing pipe to move toward the inner tube of the newly installed sieve hole drill rod, thereby realizing the internal sealing of the exposed sieve hole; Copper ring support sleeves are inlaid and installed at both ends of the inner hole of the inner layer tube.

16. The closed slag discharge system outside the hole according to claim 15, characterized in that: The dustproof component includes a cylinder and a dustproof brush installed in the cylinder. One end of the inner hole of the cylinder is installed on the outer end of the inner tube extending out of the outer tube, and the other end of the inner hole of the cylinder is installed with a dustproof brush.

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