Integrated double-channel drill rod

Abstract

The invention provides an integrated double-channel drill rod which is characterized in that a rod body is composed of an inner pipe and an outer pipe, an annular cavity is formed between the inner pipe and the outer pipe, the two ends of the rod body are provided with a male connector body and a female connector body respectively, and the male connector body and the female connector body are matched threaded connectors; the positions, corresponding to the annular cavities, of the male connector body and the female connector body are each provided with an annular water passing groove, and a plurality of water passing holes communicated with the annular cavities are formed in the annular water passing grooves. A sealing ring groove is formed in the root of the male connector body, and a sealing ring is arranged in the sealing ring groove. An equal-diameter extension section is lengthened after threads at the foremost end of the male connector body are finished, a matched sealing hole channel is formed in the corresponding position in the female connector body, a sealing ring groove is formed in the circumference of the extension section, and a sealing ring is arranged in the sealing ring groove. A novel structural form and a novel sealing mode are adopted, connection is convenient, sealing is reliable, under the condition of the same drill rod outer diameter, the area of a center hole is maximized, and the requirement of a novel horizontal directional drilling technology is better met.

Description

Technical Field

[0001] This invention belongs to the field of horizontal directional drilling technology, specifically relating to an integrated dual-channel drill rod. Background Technology

[0002] Horizontal directional drilling rigs are construction machines used to lay various underground utilities (pipelines, cables, etc.) without excavating the ground surface. They are widely used in pipeline laying projects for water supply, electricity, telecommunications, natural gas, coal gas, and oil.

[0003] Conventional horizontal directional drilling (WDD) pipe-laying technology employs grouting inside the drill pipe and grout return through the borehole for chip removal. Currently, a new process has emerged in WD pipe-laying technology that involves grouting inside the drill pipe during borehole enlargement and also using grout return through the drill pipe for chip removal. To meet the requirements of this new process, conventional WD drill pipes cannot be used; instead, a dual-channel drill pipe is required, with one channel for grouting and the other for grout return and chip removal. Because WD pipe-laying requires relatively large borehole diameters and generates a significant amount of drill cuttings, the dual-channel drill pipe used in WD needs to have a sufficiently large chip removal diameter.

[0004] A dual-channel drill pipe is a type of drill pipe where both grouting and grout return / chip removal occur within the pipe's interior. After connection, this type of drill pipe requires two mutually sealed, continuous channels: a wall interlayer channel and a central channel. The wall interlayer channel serves as the grouting channel, while the central channel is the grout return / chip removal channel. The performance of a dual-channel drill pipe, besides the torsional and tensile strengths important for ordinary drill pipes, hinges on two crucial aspects: (1) Under the same outer diameter conditions, the size of the passage area of ​​the two channels. In particular, the size of the passage area of ​​the inner hole slurry return and chip removal channel directly affects the chip removal capacity of the drill pipe.

[0005] (2) Sealing reliability of the joint connection type. If the seal fails, the grouting channel will lose pressure, which will lead to the risk of hole formation failure.

[0006] Existing dual-channel drill pipes, known as double-walled drill pipes, are used in vertical drilling, such as water well drilling. These double-walled drill pipes consist of two layers: an inner rod inserted into the outer drill pipe and fixed in the center of the outer drill pipe's inner bore using a fixing device. The connection type of this drill pipe joint is a double-layer connection—the outer rod has a threaded connection, while the inner rod has a sealed socket connection. However, if this type of double-walled drill pipe is used in horizontal directional drilling, it has the following drawbacks: (1) The connection is inconvenient, labor-intensive, and has low efficiency: Because horizontal directional drilling involves long drilling distances, frequent drill rod splicing is required. Conventional horizontal directional drilling drill rods use tapered thread connections. The spliced ​​drill rod only needs to be placed on a roughly aligned positioning bracket, and the drill rig can be driven to rotate and advance to complete the threaded connection without the need for manual alignment, resulting in high connection efficiency. However, when splicing this type of double-walled drill rod on the drill rig, the inner rod's socket interface needs to be precisely aligned for smooth insertion. When splicing drill rods on the drill rig, manual alignment and coordination with the drill rig are required, which is laborious and time-consuming.

[0007] (2) The seal is unreliable and there is a risk: Since the inner rod is installed and fixed inside the outer drill rod, there is a certain installation gap. Therefore, there is a certain deviation between the axes of the inner rod and the outer rod. During the insertion process, careless operation can easily scratch the sealing ring. If it is not detected in time, it will lead to engineering risks.

[0008] (3) The central passageway has a small area: The inner rod of the double-walled drill pipe adopts a sealed socket connection method, which occupies more internal space and makes the passage area of ​​the central channel smaller. Summary of the Invention

[0009] The purpose of this invention is to provide an integrated dual-channel drill pipe with a novel structure and sealing method, which makes it easy to connect, reliable to seal, and maximizes the central hole area under the same drill pipe outer diameter, thus better meeting the needs of the new horizontal directional drilling process.

[0010] The specific technical solution adopted by this invention is as follows: An integrated dual-channel drill rod comprises an inner tube and an outer tube, forming an annular cavity between them. Both ends of the rod are equipped with a male connector and a female connector, which are mating threaded joints. Each male and female connector has an annular water passage groove corresponding to a position within the annular cavity, and the annular water passage groove contains several water passage holes connecting the annular cavities. When connecting drill rods, the male and female connectors of the two drill rods are threaded together. The annular cavities of the two drill rods are connected through the annular water passage grooves and water passage holes inside the interconnected male and female connectors, thus forming a continuous outer channel of the drill rod located within the rod wall. The inner tubes of the two drill rods are then joined together to form a continuous inner channel of the drill rod located within the inner tube.

[0011] Preferably, the male connector body has a sealing ring groove at its root, with a sealing ring inside; after being connected to the female connector body of another drill pipe, the inner wall of the end of the female connector body and the sealing ring at the root of the male connector body are pressed together, forming a seal between the outer channel of the drill pipe and the outside world.

[0012] Preferably, the male connector body has an extension section with the same diameter as the threaded portion after the threaded end at its foremost end. A matching sealing channel is provided at a corresponding position inside the female connector body. The extension section has a sealing ring groove on its circumference, containing a sealing ring. When the two drill pipes are threaded together, the extension section of the male connector body inserts into the sealing channel inside the female connector body, forming a seal between the outer channel of the drill pipe and the inner channel of the drill pipe.

[0013] Furthermore, the male and female connectors are tapered threaded connectors, which makes alignment easier during connection.

[0014] The technical effects achieved by this invention are as follows: This invention provides an integrated dual-channel drill rod. The annular cavities of the two drill rods are connected by an annular water passage groove and water passage hole inside the interconnected male and female connector bodies, thereby forming a continuous outer channel of the drill rod located inside the rod wall, which serves as a grouting channel. The inner tubes of the two drill rods are connected to each other to form a continuous inner channel of the drill rod located inside the inner tube, which serves as a channel for grout return and chip removal. This enables grouting in the outer channel of the drill rod and grout return and chip removal in the inner channel of the drill rod.

[0015] The male and female connectors of this invention are connected by tapered threaded joints, which is convenient for docking and requires no personnel assistance. The drill rods can be directly connected by driving the drilling machine. At the same time, the design of the annular water passage groove provides a buffer transition space for the docking of the water passage holes of the male and female connectors. When the two drill rods are threaded together, it is not necessary to ensure that the water passage holes of the two drill rods are strictly aligned, so that the annular cavities of the two drill rods can be connected, thus having higher practicality and operability.

[0016] The sealing connection between drill pipes in this invention is automatically completed during the tightening of the drill pipe threads, without relying on manual alignment, thus making it more reliable.

[0017] The integrated dual-channel drill pipe of the present invention allows the inner tubes of the two drill pipes to be directly connected when the drill pipes are joined. Compared with the socket connection method of traditional double-wall drill pipes, the present invention maximizes the passage area of ​​the central hole of the inner tube and has a greater chip removal capacity under the same drill pipe outer diameter. Attached Figure Description

[0018] Figure 1 This is a cross-sectional view of an integrated dual-channel drill pipe according to the present invention; Figure 2 This is a half-sectional view of an integrated dual-channel drill pipe according to the present invention. Figure 3 This is a half-sectional view of the integrated dual-channel drill pipe in the docking state of the present invention.

[0019] The attached diagram lists the components represented by each number as follows: 1. Inner tube; 2. Outer tube; 3. Annular cavity; 4. Male connector body; 5. Female connector body; 6. Annular water passage groove; 7. Water passage hole; 8. Outer channel of drill rod; 9. Inner hole channel of drill rod; 10. First sealing ring groove; 11. Extension section; 12. Sealing channel; 13. Second sealing ring groove. Detailed Implementation

[0020] To make the objectives and advantages of this invention clearer, the invention will be specifically described below with reference to embodiments. It should be understood that the following text is merely used to describe one or more specific embodiments of the invention and does not strictly limit the scope of protection specifically claimed by the invention. Example

[0021] This embodiment provides an integrated dual-channel drill rod, the rod body is composed of an inner tube 1 and an outer tube 2, and an annular cavity 3 is formed between the inner tube 1 and the outer tube 2. Male connector 4 and female connector 5 are respectively provided at both ends of the rod body. The male connector 4 and female connector 5 are compatible and tapered threaded connectors. Each of the male connector 4 and female connector 5 has an annular water passage groove 6 corresponding to the position of the annular cavity 3. The annular water passage groove 6 has several water passage holes 7 connecting the annular cavity 3. When the drill rods are joined, they are connected by threads through the male connector 4 and female connector 5 of the two drill rods. The annular cavities 3 of the two drill rods are connected through the annular water passage groove 6 and water passage holes 7 inside the interconnected male connector 4 and female connector 5, thereby forming a continuous outer channel 8 of the drill rod located inside the rod wall; the inner tubes 1 of the two drill rods are connected to each other to form a continuous inner hole channel 9 of the drill rod located inside the inner tube 1.

[0022] The male connector body 4 has a first sealing ring groove 10 at its root, with a sealing ring inside. After being connected to the female connector body 5 of another drill rod, the inner wall of the end of the female connector body 5 is pressed against the sealing ring at the root of the male connector body 4, forming a seal between the outer channel 8 of the drill rod and the outside.

[0023] The male connector body 4 has an extension section 11 with the same diameter as the threaded portion at the end of the threaded section. A matching sealing channel 12 is located at a corresponding position inside the female connector body 5. The extension section 11 has a second sealing ring groove 13 on its circumference, containing a sealing ring. When the two drill rods are threaded together, the extension section 11 of the male connector body 4 is inserted into the sealing channel 12 inside the female connector body 5, forming a seal between the outer channel 8 and the inner channel 9 of the drill rod.

[0024] This embodiment provides an integrated dual-channel drill rod. The annular cavities 3 of the two drill rods are connected by annular water passage grooves 6 and water passage holes 7 inside the male connector body 4 and female connector body 5, thereby forming a continuous outer channel 8 of the drill rod located inside the rod wall, which serves as a grouting channel. The inner tubes 1 of the two drill rods are connected to each other to form a continuous inner hole channel 9 of the drill rod located inside the inner tube 1, which serves as a channel for grout return and chip removal. This enables grouting in the outer channel 8 of the drill rod and grout return and chip removal in the inner hole channel 9 of the drill rod.

[0025] In this embodiment, the male connector 4 and female connector 5 are connected by a tapered threaded connector, which is convenient to connect and requires no personnel assistance. The drill rig can directly complete the drill rod connection. At the same time, the design of the annular water passage groove 6 provides a buffer transition space for the connection of the water passage holes 7 of the male connector 4 and female connector 5. When the two drill rods are threaded together, it is not necessary to ensure that the water passage holes 7 of the two drill rods are strictly aligned, so that the annular cavities 3 of the two drill rods can be connected, thus having higher practicality and operability.

[0026] In this embodiment, the sealing connection between drill pipes is automatically completed during the tightening of the drill pipe threads, without relying on manual alignment, thus making it more reliable.

[0027] In this embodiment, the integrated dual-channel drill rod connects the inner tubes of the two drill rods directly. Compared with the socket connection of traditional double-wall drill rods, this design maximizes the passage area of ​​the central hole of the inner tube and provides greater chip removal capacity under the same drill rod outer diameter.

[0028] The above description is merely a preferred embodiment of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention. Structures, devices, and operating methods not specifically described or explained in this invention are implemented according to conventional methods in the art unless otherwise specified or limited.

Claims

1. An integrated dual-channel drill pipe, the pipe body being composed of an inner tube and an outer tube, with an annular cavity formed between the inner and outer tubes, and a male connector and a female connector respectively provided at both ends of the pipe body, wherein the male connector and the female connector are mating threaded connectors, characterized in that: Each of the male and female connectors has an annular water passage groove at the position corresponding to the annular cavity. The annular water passage groove has several water passage holes that connect the annular cavities. When the drill rods are connected, they are connected by threads through the male and female connectors of the two drill rods respectively. The annular cavities of the two drill rods are connected through the annular water passage grooves and water passage holes inside the interconnected male and female connectors, thereby forming a continuous outer channel of the drill rod located inside the rod wall. The inner tubes of the two drill rods are connected to each other to form a continuous inner hole channel of the drill rod located inside the inner tube.

2. The integrated dual-channel drill pipe according to claim 1, characterized in that: The male connector body has a sealing ring groove at its root, and a sealing ring is installed inside.

3. The integrated dual-channel drill pipe according to claim 1, characterized in that: The male connector body has an extension section of equal diameter after the thread ends at the front end. A matching sealing channel is provided at the corresponding position inside the female connector body. The circumference of the extension section is provided with a sealing ring groove containing a sealing ring.

4. An integrated dual-channel drill pipe according to any one of claims 1-3, characterized in that: The male and female connectors are tapered threaded connectors.

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