Through-layer drilling annular supply self-cleaning split bottom extraction and spray-stopping drilling tool

Abstract

This invention discloses a split-type bottom-hole extraction and blowout-eliminating drill bit with annular flow supply and self-cleaning mechanism for cross-layer drilling. The split-type bottom-hole extraction and blowout-eliminating drill bit is composed of a radial cavity-forming jet nozzle, a self-cleaning air intake device, and an opening and closing drill bit connected in sequence. An inner tube is installed in the inner cavity of the radial cavity-forming jet nozzle, the self-cleaning air intake device, and the opening and closing drill bit. An annular flow supply channel is formed between the inner tube and the inner cavity wall. Under the coordinated control of three slide valve assemblies, flow is supplied to the radial cavity-forming nozzle, the axial cleaning nozzle, and the opening and closing drill bit. The inner hole of the inner tube acts as a gas extraction channel during the water jet cavity-forming stage. The gas produced by the water jet cavity-forming enters the gas extraction channel through the self-cleaning air intake device. The present invention is a split-type bottom-hole extraction and blowout elimination drill bit that can adapt to changes in the drilling angle. When the drilling angle is small, a drill rod or a short drill rod can be added between the radial cavity jet and the self-cleaning air intake device. When the drilling is a horizontal hole or a downward-sloping hole, the self-cleaning air intake device can be removed.

Description

Technical Field

[0001] This invention relates to the field of coal mine gas drainage drilling technology, and in particular to a split-type bottom-hole drainage and de-gasification drilling tool with a cross-layer borehole annular supply and self-cleaning mechanism. Background Technology

[0002] Constructing inclined cross-layer boreholes within the bottom rock of outburst-prone coal seams, and drilling cross-layer boreholes in the areas to be excavated or mined within the outburst-prone coal seams, while employing high-pressure water jet cavitation to enhance permeability in the coal seam sections, is the primary method for current gas extraction and control in outburst-prone coal seams. Currently, the drill rods used for cross-layer drilling in outburst-prone coal seams in China mainly include grooved drill rods, ribbed drill rods, and prismatic grooved drill rods. A high-low pressure switching jet is installed between the drill rod at the front end and the drill bit. Under low pressure, the jet supplies flow to the drill bit; under high pressure, it supplies flow to the radial nozzle, thereby enhancing permeability by creating high-pressure water jet cavitation in the coal seam section. During the water jet cavitation process, a large amount of coal slag and gas are generated. This coal slag and gas are discharged outside the borehole through the annular gap between the drill rod surface and the borehole wall. For inclined boreholes in outburst-prone coal seams, coal slag can be discharged using its own weight and the spiral grooves, spiral ribs, and ridges on the drill rod surface. Since gas is lighter than air, it can only be discharged by pressure difference, which can lead to excessive gas levels in the blowhole. Excessive gas levels in the blowhole have become one of the main safety hazards in outburst-prone mines. At the same time, the installation of a high-low pressure conversion jet on the central flow channel makes it impossible to lower the protective screen pipe during drill retraction.

[0003] Therefore, the current high-pressure water jet slotting and cavity creation process for cross-layer drilling faces two major challenges: firstly, the problem of excessive gas levels in the blowout holes; and secondly, the difficulty in lowering the protective screen during drill retraction. To address these challenges in the high-pressure water jet slotting and cavity creation process for cross-layer drilling, the applicant submitted a "Method for Gas Extraction While Drilling in Cross-Layer Drilling and Blowout Prevention Holes" (application number 202210251353.3). The "screen hole air intake device," "high-low pressure conversion jetter," and "openable / closable drill bit" involved in this method have certain defects during use. The main defects are: Firstly, coal seam occurrence conditions are complex, and coal composition is diverse. When the content of viscous and oily substances in the coal seam is high, coal dust and sludge will accumulate and clog the outside of the conical screen plates of the "screen hole air intake device," affecting the efficiency of extraction and blowout prevention. How to make the screen hole air intake device have a self-cleaning function is a key issue. First, it can become a problem that needs to be solved. Second, at the "screen hole air intake device", the radial air intake channel (air intake hole) passes through the axial ring flow channel and connects with the axial center extraction channel. The air intake hole needs to pass through two interfaces of three different components. The sealing at the interface is quite difficult, and there is air and water leakage. This has a certain impact on the air intake efficiency of the radial air intake channel and also increases the amount of gas mixed with water extracted. How to solve the interface sealing problem of the air intake hole of the screen hole air intake device needs to be solved. Third, the "openable and closable drill bit" adopts a ring flow channel. There is no backflow prevention device installed in the ring flow channel. Coal slag enters the drill bit and settles into the ring flow channel of the section where the ejector is located, contaminating the working water medium of the ejector and affecting the normal operation and service life of the ejector.

[0004] To address the aforementioned shortcomings, this invention makes four improvements. First, a split-type bottom-hole extraction and blowout-eliminating drill bit is designed, consisting of a radial cavity-creating jet, a self-cleaning air intake device, and an opening and closing drill bit, giving the drill bit good angular adaptability. Second, different pressure-level slide valve structures are designed for the radial cavity-creating jet and the self-cleaning air intake device, respectively, to achieve synergistic cooperation between the radial cavity-creating function and the axial instantaneous clearing function, solving the external blockage problem of the "screen hole air intake device". Third, the interface leakage problem is eliminated by using an air intake transition piece and a cross-border air intake pipe, solving the internal leakage problem of the "screen hole air intake device". Fourth, a ring-flow opening and closing drill bit with anti-backflow function is designed to solve the problem of working water medium contamination of the jet. Summary of the Invention

[0005] This invention addresses the problems existing in the prior art by providing a split-type bottom-hole extraction and blowout-eliminating drilling tool with a flow-through annular supply.

[0006] The technical solution adopted to achieve the above objectives is:

[0007] A split-type bottom-hole extraction and blowout-eliminating drilling tool with annular flow supply for cross-layer drilling is characterized by comprising a radial cavity-forming jet, a self-cleaning air intake device, and an opening and closing drill bit. The radial cavity-forming jet, the self-cleaning air intake device, and the opening and closing drill bit are sequentially connected by threaded connections. Each of the radial cavity-forming jet, the self-cleaning air intake device, and the opening and closing drill bit has an inner tube installed in its inner cavity. The annular gap between the inner tube and the inner cavity wall is an annular flow supply channel. The annular flow supply channel supplies flow to the radial cavity-forming nozzle, the axial cleaning nozzle, and the opening and closing drill bit under the control of different slide valve assemblies.

[0008] The central hole of the inner tube is a gas extraction channel. The self-cleaning air intake device is equipped with a radial air intake channel. The gas produced by the radial water jet cavity creation enters the gas extraction channel through the radial air intake channel.

[0009] Furthermore, the radial cavity jet generator consists of a first valve body, a first inner tube, and a first slide valve assembly. The first inner tube is installed in the inner cavity of the first valve body, and the first slide valve assembly is installed in the annular flow channel between the first inner tube and the first valve body and controls the opening and closing of the radial cavity nozzle.

[0010] Furthermore, the first valve body is provided with a male and a female buckle at both ends, and a first buckle sealing ring is installed at the male buckle end. The first valve body is provided with four first axial ribs, and radial cavity nozzles are installed on two of the first axial ribs.

[0011] Radial cavity nozzles can also be installed on all four first axial ribs. The number of radial nozzles and the diameter of the nozzle nozzles can be adjusted according to the geological conditions of the coal seam and the pressure parameters of the pump station. The first axial ribs can be welded or machined. Inclined grooves can be machined on the first axial ribs to give the first valve body certain crushing and conveying functions. Cutting blades can be welded to the end face of the first axial ribs to facilitate the first valve body to pass through the coal-rock interface when retracting the drill. If blocked, it can be forced to pass through by reverse drilling.

[0012] Furthermore, the first inner tube is composed of a first suction pipe, a first female end support ring, a first male end support ring, and a first irregular sealing ring. The first suction pipe and the first female end support ring are connected by threads and sealed with a fixed sealing ring.

[0013] Furthermore, the first slide valve assembly consists of a first sliding ring, a first compression spring, a first limiting damping tube, a first limiting sleeve, and a limiting support ring;

[0014] The function of the first slide valve assembly is to control the radial cavity-forming nozzle to perform hydraulic cavity-forming and permeability enhancement on the coal body around the borehole under a specific hydraulic pressure. The first limiting sleeve can be replaced by a limiting retaining ring, but the groove of the retaining ring is relatively difficult to process, and the disassembly and installation of the first slide valve assembly is inconvenient.

[0015] Furthermore, the self-cleaning air intake device consists of a second valve body, a second inner tube, an air intake transition piece, a cone-shaped screen plate, a cross-border air intake pipe, and a second slide valve assembly. The second inner tube is installed in the inner cavity of the second valve body, and the second slide valve assembly is installed in the annular flow channel between the second inner tube and the second valve body.

[0016] The conical hole screen strip is installed in the axial groove, and the conical hole screen strip is provided with a number of conical holes.

[0017] Furthermore, the second valve body is provided with a male thread and a female thread at both ends, and a second thread sealing ring is installed at the male thread end. The outer surface of the second valve body is provided with second axial ribs and axial grooves that are axially corresponding and of equal number. An axial unblocking nozzle is installed on the end face of the second axial ribs, and multiple first radial holes are provided in the axial grooves.

[0018] Furthermore, the second inner tube is composed of a second suction pipe, a second female end support ring, a second male end support ring, and a second irregular sealing ring, and multiple second radial holes are provided on the second suction pipe.

[0019] Furthermore, the second slide valve assembly consists of a second sliding ring, a second compression spring, a second limiting damping tube, and a second limiting sleeve. The second slide valve assembly controls the axial unblocking nozzle to achieve instantaneous spraying under specific hydraulic pressure, thereby flushing and unblocking the coal slag sludge accumulated on the surface of the cone hole screen plate.

[0020] Furthermore, an air intake transition piece is provided in the annular flow channel between the second air extraction pipe and the second valve body, and the air intake transition piece is provided with a plurality of third radial holes.

[0021] Furthermore, after applying adhesive to the first, second, and third radial holes of the same diameter located on different components, they are tightly fitted into the cross-sectional air intake pipe. The inner hole of the cross-sectional air intake pipe is a radial air intake channel. The cross-sectional air intake pipe spans the two interfaces between the three components, enabling the radial air intake channel to pass through the axial annular flow channel and connect with the axial gas extraction channel.

[0022] Furthermore, the opening and closing drill bit is composed of a pressure bar drill bit, a third inner tube and a lost cover. The third inner tube is located inside the pressure bar drill bit, and the lost cover is located on one side of the third inner tube. The pressure bar drill bit, the third inner tube and the lost cover work together to enable the opening and closing drill bit to have the function of opening the cover, providing support for lowering the protective hole screen before retracting the drill.

[0023] The third inner tube is composed of a third irregular sealing ring, a third female end support ring, a short-connecting inner tube, a tension spring, a sliding ring, and a fixing ring. The third irregular sealing ring, the third female end support ring, the tension spring, the sliding ring, and the fixing ring are sequentially sleeved on the short-connecting inner tube, so that the opening and closing drill bit has the function of preventing backflow.

[0024] Furthermore, the first and second sealing rings are identical, as are the first, second, and third shaped sealing rings, and the first, second, and third female end support rings. The starting pressure of the second slide valve assembly is less than that of the first slide valve assembly. The second slide valve assembly opens first, implementing instantaneous jet cleaning of the axial cleaning nozzle. As the pressure continues to rise, the first slide valve assembly opens, initiating radial water jet cavitation. The second slide valve assembly then automatically closes, terminating the cleaning of the conical screen plate. In practical applications, based on the gas extraction situation, it can be determined whether the conical screen plate is blocked. If blockage occurs, the supply valve can be repeatedly opened and closed outside the hole to clean the blockage of the conical screen plate at any time.

[0025] The beneficial effects of this invention are as follows:

[0026] 1. This invention addresses the problem of coal slag and slime accumulating and clogging on the outer surface of the conical screen plate. It designs a second slide valve assembly for the air intake device and a self-cleaning air intake device, adding an instantaneous axial jet cleaning function. During each drill rod installation, the conical screen plate is flushed and cleaned once. The conical screen plate can also be repeatedly flushed and cleaned by opening and closing the supply valve outside the hole.

[0027] 2. This invention utilizes the coordinated operation of two sets of slide valve assemblies with different pressure levels, as well as a backflow prevention assembly for the drill bit, to achieve the separation, combination, and additional installation of the cavity-forming jet, the self-cleaning air intake device, and the drill bit. This allows for better adaptation to changes in the borehole inclination angle: when the borehole angle is small, a drill rod or short drill rod can be installed between the cavity-forming jet and the self-cleaning air intake device to increase the height difference between them and prevent the self-cleaning air intake equipment from being submerged in water. When the borehole is a horizontal or inclined borehole, the self-cleaning air intake device can be removed.

[0028] 3. This invention designs a ring-feed opening and closing drill bit with anti-backflow function. An anti-backflow component is set in the ring-feed channel of the drill bit. At the same time, an opening and closing method with a lost cover and a rotating pressure rod is designed. This not only facilitates the lowering of the protective screen before retracting the drill, but also prevents the water medium in the jet section from being contaminated. Attached Figure Description

[0029] Figure 1 This is a structural diagram of the split-type bottom-hole extraction and blowout elimination drill of the present invention;

[0030] Figure 2 This is a diagram showing the components and assembly of the cavity-forming jet generator in the split-type bottom-hole extraction and blowout-eliminating drill of the present invention.

[0031] Figure 3 This is an assembly and work position diagram of the cavity-forming jet device of the split-type bottom-hole extraction and blowout-eliminating drill of the present invention;

[0032] Figure 4 Other feasible solutions for the cavity-making jet device of the split-type bottom-hole extraction and blowout-eliminating drill tool of the present invention are shown in the figure.

[0033] Figure 5 These are component diagrams of the self-cleaning air intake device for the split-type bottom-hole extraction and blowout elimination drill of the present invention;

[0034] Figure 6 This is an assembly and workstation diagram of the self-cleaning air intake device for the split-type bottom-hole extraction and blowout elimination drill of the present invention.

[0035] Figure 7 Other feasible solutions for the self-cleaning air intake device of the split-type bottom hole extraction and blowout elimination drill of the present invention are shown in the figure.

[0036] Figure 8 This is a diagram showing the opening and closing drill bit structure and work position of the split-type bottom-hole extraction and blowout elimination drill tool of the present invention.

[0037] Figure 9 This is a diagram showing the split type of the split-type bottom-hole extraction and blowout elimination drill bit of the present invention as the angle changes.

[0038] Among them, 1-cavitation jet generator, 111-first sealing ring, 112-first axial rib, 1121-slanted groove, 1122-cutting blade, 113-radial cavitation nozzle, 121-first suction pipe, 122-first female end support ring, 123-first male end support ring, 124-first irregular sealing ring, 131-first sliding ring, 132-first compression spring, 133-first limiting damping tube, 134-first... 1. Limiting sleeve; 135. Limiting support ring; 1311. First sliding seal; 1312. First guide ring; 1313. First energy control surface; 136. Prestressed tension spring; 2. Self-cleaning air intake device; 211. Second snap-on sealing ring; 212. Second axial rib; 213. Axial cleaning nozzle; 214. Axial groove; 2141. First radial hole; 221. Second suction pipe; 2211. Second radial hole; 2212. - Fixed sealing ring, 222- Second female end support ring, 223- Second male end support ring, 224- Second irregular sealing ring, 23- Inlet transition piece, 231- Third radial hole, 24- Conical hole sieve strip, 241- Conical hole, 25- Cross-border intake pipe, 261- Second sliding ring, 2611- Second sliding seal, 2612- Second guide ring, 2613- Second energy control surface, 262- Second compression spring, 263- Second limiting damping tube, 264-Second limiting sleeve, 24-Conical hole screen plate, 3-Opening and closing drill bit, 31-Pressure bar drill bit, 311-Rotating pressure bar, 321-Third irregular sealing ring, 322-Third female end support ring, 323-Short connecting inner tube, 331-Tension spring, 332-Sliding ring, 333-Fixing ring, 4-Gas extraction channel, 5-Annular flow supply channel, 6-Radial air intake channel, 7-Annular flow supply extraction short section drill rod.

[0039] 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

[0040] 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.

[0041] like Figure 1-9As shown, this embodiment discloses a split-type bottom-hole extraction and blowout-eliminating drilling tool with annular flow and self-cleaning mechanism for cross-layer drilling. It includes a radial cavity-forming jet nozzle 1, a self-cleaning air intake device 2, and an opening and closing drill bit 3. The cavity-forming jet nozzle 1, the self-cleaning air intake device 2, and the opening and closing drill bit 3 are connected sequentially by threaded connections. Inner tubes (hereinafter referred to as the first inner tube, the second inner tube, and the third inner tube) are installed in the inner cavities of the three main components of the split-type bottom-hole extraction and blowout-eliminating drilling tool. The central hole of the inner tube is the gas extraction channel 4, and the annular gap between the inner tube and the inner cavity wall is the annular flow channel 5. A first slide valve assembly 13 for controlling the radial cavity-forming nozzle 113 and a second slide valve assembly 26 for controlling the axial cleaning nozzle 213 are respectively installed on the annular flow channel 5. The gas produced by the radial water jet cavity-forming and permeability enhancement enters the gas extraction channel 4 through the conical screen plate 24 on the self-cleaning air intake device 2 and the radial air intake channel 6.

[0042] like Figure 2 As shown, Figure 2 -a is a three-dimensional structural diagram of the first valve body 11. Male and female threads that can cooperate with each other are machined at both ends of the first valve body (11). The male thread end is equipped with a first thread sealing ring 111. Four first axial ribs 112 are provided on the outer surface of the first valve body 11. Radial cavity nozzles 113 are installed on two of the first axial ribs. Radial cavity nozzles can also be installed on all four first axial ribs. The number of radial nozzles and the diameter of the radial nozzle nozzles can be adjusted according to the geological conditions of the coal seam and the pressure parameters of the pump station. Inclined grooves 1121 can be machined on the first axial ribs 112 to give the first valve body a certain crushing and conveying function. Cutting blades 1122 can be set on the end face of the first axial ribs to facilitate the first valve body to pass through the coal-rock interface when the drill is withdrawn. If blocked, the cutting blades 1122 can cut the coal-rock interface to force passage.

[0043] Figure 2 -b is a perspective view of the first inner tube 12. The first inner tube 12 is composed of a first suction pipe 121, a first female end support ring 122, a first male end support ring 123 and a first irregular sealing ring 124. The first suction pipe (121) and the first female end support ring (122) are connected by threads and sealed with a fixed sealing ring (1211).

[0044] Figure 2-c is a perspective view of the first slide valve assembly 13. The first slide valve assembly 13 consists of a first sliding ring 131, a first compression spring 132, a first limiting damping tube 133, a first limiting sleeve 134, and a limiting support ring 135. A first sealing element 1311 and a first guide sleeve 1312 are installed on the first sliding ring 131. The first sealing element 1311 can be a combination of a Glyd ring and an O-ring. A first energy control surface 1313 is provided on the flow-facing surface of the first sliding ring 131. Changing the shape of the energy control surface 1313 can change the force on the first compression spring 132. The function of the first slide valve assembly 13 is to control the opening and closing of the radial cavity-forming nozzle 113.

[0045] Figure 2 -d is a three-dimensional assembly drawing of the cavity jet generator 1.

[0046] like Figure 3-4 As shown, Figure 3 -a indicates a non-jet station. Figure 3 -b indicates the jet spray station. Figure 3 The first compression spring 132 in the middle can also be used as... Figure 4 The prestressed tension spring 136 shown is replaced, and the problem is eliminated. Figure 3 The first limiting sleeve 134 in the middle, changing the type and installation position of the spring, is also within the scope of protection of this invention. In specific implementation, it is more convenient to use a compression spring slide valve assembly.

[0047] like Figure 5 As shown, the self-cleaning air intake device 2 consists of a second valve body 21, a second inner tube 22, an air intake transition piece 23, a cone-shaped screen plate 24, a cross-border air intake pipe 25, and a second slide valve assembly 26.

[0048] in, Figure 5 -a is a three-dimensional structural diagram of the second valve body 21. The two ends of the second valve body 21 are provided with male and female buckles that can be connected to each other. The male buckle end is equipped with a second buckle sealing ring 211. The outer surface of the second valve body 21 is provided with second axial ribs 212 and axial grooves 214 that are axially corresponding and equal in number. An axial unblocking nozzle 213 is installed on the end face of the second axial rib 212, and multiple first radial holes 2141 are provided in the axial groove 214.

[0049] Figure 5 -b is a three-dimensional structural diagram of the second inner tube 22. The second inner tube 22 is composed of a second suction pipe 221, a second female end support ring 222, a second male end support ring 223, and a second irregular sealing ring 224. Multiple second radial holes 2211 are provided on the second suction pipe 221.

[0050] Figure 5 -c is a three-dimensional structural diagram of the intake transition piece 23, on which multiple third radial holes 231 are provided;

[0051] Figure 5 -d is a schematic diagram of the conical hole screen strip 24. A large number of conical holes 241 are provided on the conical hole screen strip 24. The width of the conical hole screen strip 24 should correspond to the width of the axial groove 214. The conical hole screen strip 24 is welded or embedded in the axial groove 214.

[0052] Figure 5 -e refers to the cross-sectional intake pipe 25, which is a short section of steel pipe with its inner diameter being... Figure 1 The radial air intake channel 6 is shown.

[0053] Figure 5 -f is a three-dimensional view of the components of the second slide valve assembly 26. The second slide valve assembly 26 consists of a second sliding ring 261, a second compression spring 262, a second limiting damping tube 263, and a second limiting sleeve 264. A second energy control surface 2613 is provided on the flow-facing surface of the second sliding ring 261. A second sliding seal 2611 and a second guide ring 2612 are provided on the outer circle of the second sliding ring 261. The function of the second slide valve assembly is to control the axial unblocking nozzle to achieve instantaneous spraying under a specific hydraulic pressure, so as to flush and unblock the coal slag sludge accumulated on the outer surface of the cone hole screen plate 24.

[0054] like Figure 6-7 As shown, where Figure 6 -a is a 3D assembly diagram of the self-cleaning air intake device. Figure 6 -b represents the non-axial unblocking workstation diagram. Figure 6 -c represents the axial unblocking station diagram, such as... Figure 7 As shown, the second slide valve assembly can also be installed on the female buckle end, which is also within the scope of protection of this invention.

[0055] like Figure 8 As shown, the opening and closing drill bit 3 is composed of a pressure bar drill bit 31, a third inner tube 32, and a lost cover 33. The third inner tube 32 is composed of a third irregular sealing ring 321, a third female end support ring 322, a short-connecting inner tube 323, a tension spring 324, a sliding ring 325, and a fixing ring 326. The pressure bar drill bit 31, the third inner tube 32, and the lost cover 33 work together to enable the opening and closing drill bit 3 to have the function of opening the cover, providing support for lowering the protective hole screen before retracting the drill. The tension spring 324, the sliding ring 325, and the fixing ring 326 work together to enable the opening and closing drill bit to have the function of preventing backflow.

[0056] like Figure 1-8As shown, the first sealing ring 111 and the second sealing ring 211 are the same; the first irregular sealing ring 124, the second irregular sealing ring 224 and the third irregular sealing ring 321 are the same; the first female end support ring 122, the second female end support ring 222 and the third female end support ring 322 are the same; the first slide valve assembly 13 and the second slide valve assembly 26 have the same structural principle. The starting pressure of the second slide valve assembly 26 is less than the starting pressure of the first slide valve assembly 13. The second slide valve assembly opens first, implementing instantaneous jet cleaning of the axial cleaning nozzle 213. As the pressure continues to rise, the first slide valve assembly 13 opens, starting radial water jet cavitation. The second slide valve assembly 26 then automatically closes, terminating the cleaning of the conical screen plate. In practical applications, based on the gas extraction situation, it can be determined whether the conical screen plate 24 is blocked. If blockage occurs, the supply valve can be repeatedly opened and closed outside the hole to clean the blockage of the conical screen plate 24 at any time.

[0057] like Figure 9 As shown, when the borehole inclination angle increases, the following method is adopted: Figure 9 -a shows the three-part combination of the cavity-forming jet device 1, the self-cleaning air intake device 2, and the opening and closing drill bit 3; when the drilling angle is small, a short section of drill rod 7 or a whole drill rod can be added between the cavity-forming jet device 1 and the self-cleaning air intake device 2 to increase the height difference between the self-cleaning air intake device 2 and the cavity-forming jet device 1, and to prevent the self-cleaning air intake device 2 from being submerged by water and coal slag; when the drilling is a horizontal drilling or a downward drilling, the self-cleaning air intake device 2 can be removed.

[0058] To address the shortcomings of existing technologies, this invention makes four improvements: First, a split-type bottom-hole extraction and blowout-eliminating drill bit is designed, consisting of a radial cavity-creating jet, a self-cleaning air intake device, and an opening and closing drill bit, giving the drill bit good angular adaptability. Second, different pressure-level slide valve structures are designed for the radial cavity-creating jet and the self-cleaning air intake device, respectively, to achieve synergistic cooperation between the radial cavity-creating function and the axial instantaneous clearing function, solving the external blockage problem of the "screen hole air intake device". Third, the interface leakage problem is eliminated by using an air intake transition piece and a cross-border air intake pipe, solving the internal leakage problem of the "screen hole air intake device". Fourth, a ring-flow opening and closing drill bit with anti-backflow function is designed to solve the problem of working water medium contamination of the jet.

[0059] Specifically, in response to the problem of coal slag and slime accumulating and clogging on the outer surface of the cone-shaped screen plate, a second slide valve assembly was designed for the air intake device, and a self-cleaning air intake device was designed, with the addition of an instantaneous axial jet cleaning function. Each time the drill rod is installed, the cone-shaped screen plate is flushed and cleaned once. The cone-shaped screen plate can also be repeatedly flushed and cleaned by opening and closing the supply valve outside the hole.

[0060] By utilizing the coordinated operation of two sets of slide valve assemblies with different pressure levels, as well as the anti-backflow assembly for the drill bit, the separation, combination, and additional installation of the cavity jet generator, the self-cleaning air intake device, and the opening and closing drill bit can be achieved, which can better adapt to changes in the drilling angle: when the drilling angle is small, a drill rod or short drill rod can be installed between the cavity jet generator and the self-cleaning air intake device to increase the height difference between the self-cleaning air intake device and the cavity jet generator, preventing the self-cleaning air intake equipment from being submerged in water; when the drilling is a horizontal drilling or inclined drilling, the self-cleaning air intake device can be removed.

[0061] An anti-backflow component is installed in the annular flow channel of the drill bit. At the same time, an opening and closing method is designed with the cooperation of a lost cover and a rotating pressure rod. This not only facilitates the lowering of the protective screen before retracting the drill bit, but also prevents the water medium in the jet section from being contaminated.

[0062] If this patent uses terms such as "first" and "second" to define components, those skilled in the art should know that the use of "first" and "second" is merely for the convenience of describing the invention and simplifying the description, and the above terms have no special meaning.

[0063] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the claims. The scope of protection of this invention is defined by the appended claims and their equivalents.

[0064] In the description of this invention, it should be understood that the terms "front", "rear", "left", "right", "up", "down", "center", 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.

[0065] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

Claims

1. A split-type bottom-hole extraction and blowout-eliminating drilling tool with a flow-through annular feed system, characterized in that: The device includes a radial cavity jet injector (1), a self-cleaning air intake device (2), and an opening and closing drill bit (3). The radial cavity jet injector (1), the self-cleaning air intake device (2), and the opening and closing drill bit (3) are connected by threaded connections in sequence. The inner cavity of the radial cavity jet injector (1), the self-cleaning air intake device (2), and the opening and closing drill bit (3) are all equipped with an inner tube. The annular gap between the inner tube and the inner cavity wall is an annular flow supply channel (5). The annular flow supply channel (5) supplies flow to the radial cavity nozzle (113), the axial cleaning nozzle (213), and the opening and closing drill bit (3) under the control of different slide valve assemblies. The central hole of the inner tube is a gas extraction channel (4). The self-cleaning air intake device (2) is provided with a radial air intake channel (6). The gas produced by the radial water jet cavitation enters the gas extraction channel (4) through the radial air intake channel (6). The opening and closing drill bit (3) is composed of a pressure bar drill bit (31), a third inner tube (32) and a lost cover (33). The third inner tube (32) is located inside the pressure bar drill bit (31), and the lost cover (33) is located on one side of the third inner tube (32). The pressure bar drill bit, the third inner tube and the lost cover work together to enable the opening and closing drill bit to have the function of opening the cover, providing support for lowering the protective hole screen before retracting the drill. The third inner tube (32) is composed of a third irregular sealing ring (321), a third female end support ring (322), a short-connecting inner tube (323), a tension spring (324), a sliding ring (325), and a fixing ring (326). The third irregular sealing ring (321), the third female end support ring (322), the tension spring (324), the sliding ring (325), and the fixing ring (326) are sequentially sleeved on the short-connecting inner tube (323) so that the opening and closing drill bit has the function of preventing backflow.

2. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drill bit with a perforated ring supply according to claim 1, characterized in that, The radial cavity jet generator (1) consists of a first valve body (11), a first inner tube (12), and a first slide valve assembly (13). The first inner tube (12) is installed in the inner cavity of the first valve body (11), and the first slide valve assembly (13) is installed in the annular flow channel between the first inner tube (12) and the first valve body (11) and controls the opening and closing of the radial cavity nozzle (113).

3. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drilling tool with a perforated ring supply according to claim 2, characterized in that, The first valve body (11) is provided with a male buckle and a female buckle at both ends respectively. The male buckle end is equipped with a first buckle sealing ring (111). The first valve body (11) is provided with four first axial ribs (112), and a radial cavity nozzle (113) is installed on two of the first axial ribs (112).

4. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drilling tool with a perforated ring supply according to claim 3, characterized in that, The first inner tube (12) is composed of a first suction pipe (121), a first female end support ring (122), a first male end support ring (123) and a first irregular sealing ring (124). The first suction pipe (121) and the first female end support ring (122) are connected by threads and sealed with a fixed sealing ring (1211).

5. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drill bit with a perforated ring supply according to claim 4, characterized in that, The first slide valve assembly (13) consists of a first sliding ring (131), a first compression spring (132), a first limiting damping tube (133), a first limiting sleeve (134), and a limiting support ring (135).

6. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drill bit with a perforated ring supply according to claim 1, characterized in that, The self-cleaning air intake device (2) consists of a second valve body (21), a second inner tube (22), an air intake transition piece (23), a cone-shaped screen plate (24), a cross-border air intake pipe (25), and a second slide valve assembly (26). The second inner tube (22) is installed in the inner cavity of the second valve body (21), and the second slide valve assembly (26) is installed in the annular flow channel between the second inner tube (22) and the second valve body (21). The conical hole screen plate (24) is installed in the axial groove (214), and the conical hole screen plate (24) is provided with a plurality of conical holes (241).

7. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drilling tool with a perforated ring supply according to claim 6, characterized in that, The second valve body (21) is provided with a male and a female thread at both ends. The male thread end is equipped with a second thread sealing ring (211). The outer surface of the second valve body (21) is provided with a second axial rib (212) and an axial groove (214) that are axially corresponding and equal in number. An axial unblocking nozzle (213) is installed on the end face of the second axial rib. Multiple first radial holes (2141) are provided in the axial groove.

8. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drilling tool with a perforated ring supply according to claim 7, characterized in that, The second inner tube (22) is composed of a second air extraction tube (221), a second female end support ring (222), a second male end support ring (223), and a second irregular sealing ring (224), and multiple second radial holes (2211) are provided on the second air extraction tube (221).

9. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drill bit with a perforated ring supply according to claim 8, characterized in that, The second slide valve assembly (26) consists of a second sliding ring (261), a second compression spring (262), a second limiting damping tube (263), and a second limiting sleeve (264). The second slide valve assembly (26) controls the axial unblocking nozzle (213) to achieve instantaneous spraying under a specific hydraulic pressure, thereby flushing and unblocking the coal slag sludge accumulated on the surface of the cone hole screen plate (24).

10. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drill bit with a perforated ring supply system according to claim 9, characterized in that, An air intake transition piece (23) is provided in the annular flow channel between the second air extraction pipe (221) and the second valve body (21), and the air intake transition piece (23) is provided with a plurality of third radial holes (231).

11. The self-cleaning, split-type bottom-hole extraction and blowout-eliminating drill bit with a perforated ring supply system according to claim 10, characterized in that, After the first radial hole (2141), the second radial hole (2211) and the third radial hole (231) with the same number of diameters on different components are coated with glue, they are tightly fitted into the cross-border air intake pipe (25). The inner hole of the cross-border air intake pipe (25) is a radial air intake channel (6). The cross-border air intake pipe (25) spans the two interfaces between the three components, so that the radial air intake channel (6) passes through the axial ring flow channel (5) and is connected to the axial gas extraction channel (4).

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