Underground coal mine plug-in type insulating drill rod
By combining a plug-in structure with an insulating coating, the problems of wear, corrosion, and insufficient connection strength of traditional underground drill pipes in coal mines are solved, achieving high-strength insulation and conductivity in complex environments, thus ensuring the safety and reliability of underground coal mine operations.
Patent Information
- Application Number
- CN202520792314.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-24
- Publication Date
- 2026-01-27
- Estimated Expiration
- 2035-04-24
AI Technical Summary
Traditional underground drill pipes in coal mines are prone to wear and corrosion in complex environments, resulting in short service life and insufficient connection strength, posing safety hazards. In particular, their insufficient electrical conductivity in environments containing flammable and explosive gases can easily lead to accidents.
It adopts a plug-in structure, using stainless steel to manufacture male and female connectors and square pins, which are fixed by welding. Combined with an insulating coating and an insulating sleeve, it forms a stable insulation and conductive path, and optimizes the connection structure to improve strength and insulation performance.
It improves the connection strength and insulation performance of drill pipe, extends service life, reduces the risk of wear and corrosion, and ensures the safety and reliability of downhole operations.
Smart Images
Figure CN223839059U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of underground drill pipes in coal mines, and in particular to an underground plug-in insulated drill pipe for coal mines. Background Technology
[0002] In underground coal mining operations, drill pipe is a crucial tool; it is mainly used to drill holes in coal seams or rock formations to achieve key tasks such as gas extraction, water exploration, and grouting, providing important support for safe production and efficient mining in coal mines.
[0003] Traditional coal mine drill pipes typically consist of a metal rod body and threaded joints. Over long-term use, these drill pipes have revealed a series of problems. On the one hand, due to the complexity and harshness of the underground environment, drill pipes are susceptible to wear, corrosion, and deformation, resulting in a short service life and frequent replacements, increasing mining costs and downtime. On the other hand, in some special coal mine operating scenarios, such as environments containing flammable and explosive gases like methane, drill pipes need to have good electrical conductivity to prevent static electricity buildup and accidents. However, traditional drill pipes are usually conductive, which to some extent increases safety hazards.
[0004] To address these issues, engineers developed several improvements, such as applying wear-resistant and corrosion-resistant coatings to the drill pipe surface and using insulating materials for localized insulation. However, these methods often have limitations. For instance, the coatings have a limited lifespan and are prone to wear and detachment in complex downhole environments; while localized insulation may not meet the insulation requirements of the entire drill pipe system and can easily lead to weak points in insulation at connection points.
[0005] Furthermore, with the increasing depth of coal mining and the growing complexity of mining conditions, higher requirements are placed on the mechanical properties and connection strength of drill pipes. Traditional drill pipe connection methods mainly rely on threaded connections, which are prone to problems such as loosening and damage of threads when subjected to large tensile, compressive and torsional forces, affecting the overall performance and service life of the drill pipe. Utility Model Content
[0006] To address the shortcomings in insulation and load-bearing performance of existing technologies, this utility model provides a plug-in insulated drill rod for underground coal mines.
[0007] This utility model provides a plug-in insulated drill rod for underground coal mines, employing the following technical solution:
[0008] A plug-in insulated drill rod for coal mines comprises an outer drill rod and a core drill rod. The outer drill rod includes a male connector, a female connector, and two symmetrically distributed square pins. The male connector has a male thread on its outer side at the front end and two square through holes on its outer cylindrical surface at the rear end. The female connector has an internal thread at the rear end and two square through slots on its outer cylindrical surface at the front end. The front end of the female connector is inserted into the rear end of the male connector, so that the square through holes and square through slots form a complete square through hole groove. The square pins pass through the square through hole groove to connect to and keep the outer cylindrical surface of the male connector flush.
[0009] The drill rod core includes an insulating sleeve, an insulating rod, a sealing bolt, and a fixing ring. There are two fixing rings, which are respectively fitted onto the outer circular surfaces of the insulating sleeve and the sealing bolt. The insulating sleeve is connected to one end of the insulating rod by an internal thread and is sealed with an O-ring. The sealing bolt is connected to the other end of the insulating rod by a thread and is sealed with an O-ring. The fixing rings fix the core inside the outside of the drill rod.
[0010] Furthermore, the drill rod core also includes a spring, a core body, and a connecting stud; the core body is fixedly installed inside the insulating sleeve; a spring is fixedly installed at one end of the core body; the other end of the core body is connected to a connecting stud via a thread; the other end of the connecting stud passes through the insulating rod and is threadedly connected to a sealing bolt.
[0011] Furthermore, the outer surfaces of the female connector and the male connector that come into contact with each other are uniformly coated with an insulating coating with a thickness of ≥0.3mm, and the surface insulation resistance of the insulating coating is ≥50MΩ;
[0012] Furthermore, the male connector serves as one conductive pole, while the female connector forms the other conductive pole through a spring, core, connecting stud, sealing bolt, and retaining ring.
[0013] Furthermore, the male connector, female connector, and square pin are all made of stainless steel, and the male connector and square pin are fixed by welding after insertion.
[0014] Furthermore, the sealing bolt has a threaded hole inside that mates with the connecting stud, forming an axial tensioning structure;
[0015] Furthermore, the inner wall of the front end of the male connector and the inner wall of the rear end of the female connector are both provided with stepped circular surfaces; the fixing ring is a stepped annular structure, which respectively clamps the insulating sleeve and the sealing bolt onto the stepped circular surfaces of the inner walls of the male connector and the female connector.
[0016] In summary, the beneficial effects of this utility model are as follows:
[0017] This invention effectively solves the problems of uneven insulation coating thickness and unstable insulation effect by uniformly spraying an insulating coating with a thickness of ≥0.3mm on the outer surface of the female connector and the male connector in contact, and ensuring that the surface insulation resistance of the insulating coating is ≥50MΩ; at the same time, it optimizes the connection structure, reduces the risk of insulation failure due to improper assembly, and improves the assembly yield.
[0018] The connection structure of the male connector, female connector, and square pin is made of stainless steel and combined with welding and other processes, which greatly improves the connection strength and shear resistance of the drill pipe. The square pin connection provides a larger contact area and stronger mechanical properties than the traditional threaded connection, and can withstand greater tensile, compressive, and torsional forces, effectively preventing damage caused by excessive force during use and ensuring the reliable operation of the drill pipe in complex downhole environments. Attached Figure Description
[0019] Figure 1 This is a front sectional view of the plug-in insulated drill rod for underground coal mines according to this utility model.
[0020] Figure 2 This is an external three-dimensional exploded view of the plug-in insulated drill rod for underground coal mines according to this utility model.
[0021] As shown in the figure: 1. Female connector; 2. Male connector; 3. Insulating sleeve; 4. Retaining ring; 5. Core; 6. Connecting stud; 8. Spring; 9. Square pin; 10. Insulating rod; 11. Sealing bolt; 1-1. Square through groove; 1-2. Dividing end face; 1-3. Insulating coating; 1-4. Female thread; 2-1. Square through hole groove; 2-2. Male thread. Detailed Implementation
[0022] The following is in conjunction with the appendix Figure 1 , 2 The present invention will be further described in detail below:
[0023] This utility model discloses a plug-in insulated drill rod for underground coal mines, such as... Figure 1 , 2As shown, a plug-in insulated drill rod for underground coal mines consists of an outer drill rod and a core drill rod. The outer drill rod includes a male connector 2, a female connector 1, and two symmetrically distributed square pins 9. The male connector 2 has a male thread 2-2 on its outer side at the front end and two square through holes 2-1 on its outer cylindrical surface at the rear end. The female connector 1 has a female thread 1-4 at its rear end and two square through slots 1-1 on its outer cylindrical surface at the front end. The front end of the female connector 1 is inserted into the rear end of the male connector 2, so that the square through holes 2-1 and the square through slots 1-1 form a complete square through hole groove. The square pins 9 pass through this square through hole groove to connect and keep the outer cylindrical surface of the male connector 2 flush. In this embodiment, the male connector 2 and the female connector 1 are connected by the square pins 9 passing through the complete through hole groove formed by the square through holes 2-1 and the square through slots 1-1. This connection method is similar to a mortise and tenon joint. The square pin 9 serves a positioning and fixing function, restricting the relative movement of the male connector 2 and the female connector 1 in the axial and circumferential directions. The male thread 2-2 at the front end of the male connector 2 and the female thread 1-4 at the rear end of the female connector 1 can be connected to other drill pipes or equipment to extend and assemble the drill pipe. The connection method of the square pin 9 provides a larger contact area and stronger shear resistance than the traditional threaded connection, and can withstand greater tensile, compressive and torsional forces, reducing the risk of drill pipe damage due to excessive force during use. The fit between the square through hole 2-1 and the through groove 1-1 makes the assembly of the male connector 2 and the female connector 1 more precise, ensuring the concentricity and stability of the drill pipe and improving the overall performance of the drill pipe. In addition, keeping the outer surface of the male connector 2 flush is conducive to the smooth operation of the drill pipe downhole, reducing friction and collision with the well wall, and reducing the probability of wear and damage to the drill pipe.
[0024] The drill rod core includes an insulating sleeve 3, an insulating rod 10, a sealing bolt 11, and a fixing ring 4. There are two fixing rings 4, which are respectively fitted onto the outer surfaces of the insulating sleeve 3 and the sealing bolt 11. One end of the insulating sleeve 3 is connected to the insulating rod 10 via an internal thread and is sealed with a double O-ring. The other end of the sealing bolt 11 is threaded to the insulating rod 10 and is also sealed with an O-ring. The fixing rings 4 fix the core inside the drill rod. In this embodiment, the insulating sleeve 3 and the insulating rod 10 are made of insulating material, which can effectively isolate the current conduction between the male connector 2 and the female connector 1, realizing the insulation function of the drill rod. The sealing structure of the ring prevents liquid and dust from entering the drill pipe, protecting the core structure from damage and ensuring the stability of insulation performance. The fixing ring 4, by fitting onto the outer surface of the insulating sleeve 3 and the sealing bolt 11, fixes the core to the outside of the drill pipe, ensuring the stability of the core structure and preventing displacement during drill pipe use. The use of the insulating sleeve 3 and the insulating rod 10 effectively realizes the insulation function of the drill pipe, avoiding problems such as current leakage and short circuits, and improving the safety of underground coal mine operations. The setting of the fixing ring 4 ensures the stability of the core structure, improving the overall reliability and stability of the drill pipe.
[0025] like Figure 1 , 2 As shown, the drill rod core also includes a spring 8, a core body 5, and a connecting stud 6; the core body 5 is fixedly installed inside the insulating sleeve 3; a spring 8 is fixedly installed at one end of the core body 5; the other end of the core body 5 is threadedly connected to the connecting stud 6; the other end of the connecting stud 6 passes through the insulating rod 10 and is threadedly connected to the sealing bolt 11; in this embodiment, the core body 5, the connecting stud 6, and the sealing bolt 11 form a conductive path, which forms two conductive poles with the male connector 2, realizing the conductive function of the drill rod; through the conductive path formed by the core body 5, the connecting stud 6, and the sealing bolt 11, the conductive function of the drill rod is realized, meeting the requirements for current conduction in underground coal mine operations;
[0026] like Figure 1 , 2 As shown, the outer surfaces of the female connector 1 and the male connector 2 that are in contact are uniformly coated with an insulating coating 1-3 with a thickness ≥ 0.3 mm. The surface insulation resistance of the insulating coating 1-3 is ≥ 50 MΩ. In this embodiment, the insulating coating 1-3 is made of a material with high insulation performance and is sprayed on the outer surfaces of the female connector 1 and the male connector 2 to form an insulating barrier, preventing current from being conducted between the male connector 2 and the female connector 1. The setting of the insulating coating 1-3 further improves the insulation performance of the drill pipe, reduces the risk of current leakage, and improves the safety of underground coal mine operations. The coating thickness can be made uniform through the spraying process, avoiding the problem of uneven coating thickness in traditional manual spraying, and improving the insulation effect of the drill pipe and the assembly yield.
[0027] like Figure 1 , 2 As shown, the male connector 2 serves as one conductive pole, and the female connector 1 forms the other conductive pole through the spring 8, core 5, connecting stud 6, sealing bolt 11, and retaining ring 4.
[0028] like Figure 1 , 2 As shown, the male connector 2, female connector 1, and square pin 9 are all made of stainless steel. The male connector 2 and the square pin 9 are fixed by welding after insertion. In this embodiment, stainless steel has good corrosion resistance and strength, which can adapt to the harsh working environment in coal mines and ensure the service life of the drill pipe. Welding can firmly connect the male connector 2 and the square pin 9 together, improve the strength and stability of the connection, and prevent the square pin 9 from loosening or falling off during use. It improves the corrosion resistance of the drill pipe, reduces damage caused by corrosion, and extends the service life of the drill pipe. It also improves the overall reliability and stability of the drill pipe.
[0029] like Figure 1 , 2 As shown, the sealing bolt 11 has a threaded hole inside that mates with the connecting stud 6, forming an axial tension structure. In this embodiment, the threaded engagement between the connecting stud 6 and the sealing bolt 11 creates an axial tension force, which tightly fixes the core structure inside the drill rod, preventing the core structure from loosening or shifting during drill rod use. The axial tension structure ensures the stability of the core structure's position, improves the overall reliability and stability of the drill rod, and reduces malfunctions and damage caused by loosening of the core structure.
[0030] like Figure 1 , 2 As shown, the inner wall of the front end of the male connector 2 and the inner wall of the rear end of the female connector 1 are both provided with stepped circular surfaces; the fixing ring 4 is a stepped annular structure, which respectively clamps the insulating sleeve 3 and the sealing bolt 11 onto the stepped circular surfaces of the inner walls of the male connector 2 and the female connector 1; in this embodiment, the cooperation of the stepped circular surface and the stepped annular structure forms a clamping structure, which firmly fixes the insulating sleeve 3 and the sealing bolt 11 onto the inner walls of the male connector 2 and the female connector 1 through the fixing ring 4, preventing the core structure from moving in the axial and circumferential directions; ensuring the positional stability and concentricity of the core structure, and improving the overall performance of the drill pipe; at the same time, the clamping structure provides a reliable fixing effect, preventing the core structure from loosening or shifting during the use of the drill pipe, and extending the service life of the drill pipe.
[0031] The foregoing has shown and described the basic principles, main features, and advantages of this utility model. The various components mentioned in this utility model are common technologies in the existing field. Those skilled in the art should understand that this utility model is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of this utility model. Various changes and modifications can be made to this utility model 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 utility model is defined by the appended claims and their equivalents.
Claims
1. A plug-in insulated drill rod for underground coal mines, comprising an outer drill rod and a core drill rod, characterized in that: The drill pipe includes a male connector (2), a female connector (1), and two symmetrically distributed square pins (9). The male connector (2) has a male thread (2-2) on its outer side wall at the front end and two square through holes (2-1) on its outer cylindrical surface at the rear end. The female connector (1) has an internal thread (1-4) at the rear end and two square through slots (1-1) on its outer cylindrical surface at the front end. The front end of the female connector (1) is inserted into the rear end of the male connector (2), so that the square through holes (2-1) and the square through slots (1-1) form a complete square through hole groove. The square pins (9) pass through the square through hole groove to connect and keep the outer circular surface of the male connector (2) flush. The drill rod core includes an insulating sleeve (3), an insulating rod (10), a sealing bolt (11), and a fixing ring (4). There are two fixing rings (4), which are respectively fitted onto the outer surfaces of the insulating sleeve (3) and the sealing bolt (11). One end of the insulating sleeve (3) is connected to the insulating rod (10) by an internal thread and is sealed with an O-ring. The other end of the sealing bolt (11) is connected to the insulating rod (10) by a thread and is sealed with an O-ring. The fixing ring (4) fixes the core inside the outside of the drill rod.
2. The plug-in insulated drill rod for underground coal mines according to claim 1, characterized in that: The drill rod core also includes a spring (8), a core body (5), and a connecting stud (6); the core body (5) is fixedly installed inside the insulating sleeve (3); a spring (8) is fixedly installed at one end of the core body (5); the other end of the core body (5) is connected to the connecting stud (6) by a thread; the other end of the connecting stud (6) passes through the insulating rod (10) and is threadedly connected to the sealing bolt (11).
3. The plug-in insulated drill rod for underground coal mines according to claim 1, characterized in that: The outer surfaces of the female connector (1) and the male connector (2) that are in contact are uniformly sprayed with an insulating coating (1-3) with a thickness of ≥0.3mm, and the surface insulation resistance of the insulating coating (1-3) is ≥50MΩ.
4. The plug-in insulated drill rod for underground coal mines according to claim 2, characterized in that: The male connector (2) serves as one conductive pole, while the female connector (1) forms the other conductive pole through the spring (8), core (5), connecting stud (6), sealing bolt (11), and retaining ring (4).
5. The plug-in insulated drill rod for underground coal mines according to claim 1, characterized in that: The male connector (2), female connector (1) and square pin (9) are all made of stainless steel. The male connector (2) and square pin (9) are fixed by welding after insertion.
6. A plug-in insulated drill rod for underground coal mines according to claim 2, characterized in that: The sealing bolt (11) has a threaded hole inside that mates with the connecting stud (6), forming an axial tensioning structure.
7. The plug-in insulated drill rod for underground coal mines according to claim 1, characterized in that: The inner wall of the front end of the male connector (2) and the inner wall of the rear end of the female connector (1) are both provided with stepped circular surfaces; the fixing ring (4) is a stepped ring structure, which respectively clamps the insulating sleeve (3) and the sealing bolt (11) onto the stepped circular surfaces of the inner walls of the male connector (2) and the female connector (1).