Coal seam shield pressure relief drill pipe

Abstract

The utility model belongs to coal mining equipment field especially relates to a coal seam shield protection pressure relief drill rod. Including the drill pipe outer tube and the drill pipe inner tube of the drill pipe outer tube outside, the cross section of drill pipe outer tube is square setting, the corner of drill pipe outer tube is arc surface setting. Compared with prior art, the utility model has the advantages and positive effects that: the utility model provides a coal seam shield pressure relief drill rod, improves the structure of the existing drill rod, utilizes the overall structure cooperation arc surface setting of square, can form the effect of scraping the hole to the drilling, and then improves the stability of drilling, thereby achieves the purpose of reducing the hole collapse.

Description

Technical Field

[0001] This utility model belongs to the field of coal mining equipment, and in particular relates to a coal seam shield pressure relief drill rod. Background Technology

[0002] Drilling into the coal seam where outbursts occur is a recognized global challenge. Due to the limited drilling depth in the coal seam, outburst-prone mines are forced to use bottom-penetrating drilling to extract gas, which significantly increases the cost of gas extraction and control, seriously affecting the economic benefits of coal mining enterprises.

[0003] To address the problem of drilling through outburst-prone coal seams, a shield-supported pressure-relief drilling method has been proposed. This method involves dynamically supporting the borehole with drill rods slightly smaller in diameter than the borehole to prevent borehole collapse; promptly removing drill cuttings from high-stress areas to reduce pressure and decrease drilling resistance, preventing drill bit jamming and sticking; and simultaneously reducing drill rod disturbance and borehole deviation.

[0004] Although this drilling method can effectively reduce the phenomenon of hole collapse, there is still a certain possibility of hole collapse. Therefore, how to further reduce hole collapse is the key research direction for shield construction. Utility Model Content

[0005] This utility model addresses the problem of hole collapse during existing shield protection construction by proposing a coal seam shield protection pressure relief drill rod that is reasonably designed, simple in structure, easy to manufacture, and can further reduce the risk of hole collapse.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows: This utility model provides a coal seam shield protection pressure relief drill rod, including an outer drill rod tube and an inner drill rod tube fitted outside the outer drill rod tube. The cross-section of the outer drill rod tube is square, and the corners of the outer drill rod tube are arc-shaped.

[0007] Preferably, a retainer is provided on the inner wall of the outer tube of the drill pipe, the retainer is located near both ends of the outer tube of the drill pipe, the inner tube of the drill pipe passes through the retainer, a fixing cap is fitted on the inner tube of the drill pipe, the fixing cap is connected to the retainer, and the inner tube of the drill pipe is mounted on the retainer through the fixing cap.

[0008] Preferably, the inner wall of the drill pipe is provided with helical blades, which are disposed between two retainers.

[0009] Preferably, the inner tube of the drill pipe has evenly distributed insertion protrusions on the side wall of one end, the cross-section of the insertion protrusions being semi-circular, and the other end of the inner tube of the drill pipe having a plug cap that mates with the insertion protrusions.

[0010] Preferably, the retainer is interference-fitted to the drill pipe outer tube.

[0011] Compared with the prior art, the advantages and positive effects of this utility model are as follows: This utility model provides a coal seam shield protection pressure relief drill rod. By improving the structure of the existing drill rod, the square overall structure combined with the arc surface setting can form a scraping effect on the drill hole, thereby improving the stability of the drill hole and reducing the collapse of the hole. Attached Figure Description

[0012] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 This is a schematic diagram of the structure of the coal seam shield pressure relief drill rod provided in Example 1; Figure 2 This is a schematic diagram of the structure of the coal seam shield pressure relief drill rod in a semi-section state provided in Example 1; Figure 3 This is a schematic diagram of the structure of the fixing cap provided in Example 1; In the above figures, 1. Outer tube of drill pipe; 11. Horizontal plane; 12. Arc surface; 2. Inner tube of drill pipe; 21. Helical blade; 22. Male end; 221. Insertion protrusion; 23. Insertion cap; 3. Retainer; 4. Fixing cap. Detailed Implementation

[0014] To better understand the above-mentioned objectives, features, and advantages of this utility model, the present utility model will be further described below with reference to the accompanying drawings and embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be combined with each other.

[0015] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the present invention is not limited to the specific embodiments disclosed in the following specification.

[0016] Example 1, as Figure 1 , Figure 2 As shown, this embodiment aims to solve the technical problem that existing shield drill rods still have a certain degree of hole collapse during construction. To this end, the coal seam shield pressure relief drill rod provided in this embodiment includes an outer drill rod tube 1 and an inner drill rod tube 2 fitted outside the outer drill rod tube 1. The above components are common components of existing shield drill rods, so they will not be described in detail in this embodiment.

[0017] To reduce borehole collapse, compared to the traditional circular outer tube design, in this embodiment, the drill pipe outer tube 1 has a square cross-section, and its corners are formed by arc surfaces 12. Specifically, the outer wall of the drill pipe outer tube 1 includes four horizontal surfaces 11 and four arc surfaces 12, with the arc surfaces 12 located at the junctions of the four horizontal surfaces 11. This gives the entire drill pipe outer tube 1 eight corners. The corners are designed to accommodate the large amount of coal slurry contained within the borehole. During drill pipe rotation, the corners of the drill pipe outer tube 1 carry away some coal slurry, similar to the action of plastering in construction, scraping the coal slurry onto the inner wall of the borehole to form a protective layer, thus reducing the likelihood of borehole collapse.

[0018] To facilitate the installation of the drill pipe inner tube 2, in this embodiment, a retainer 3 is provided on the inner wall of the drill pipe outer tube 1. In this embodiment, the retainer 3 includes an intermediate retaining ring and a connecting column provided on the side wall of the intermediate retaining ring. In this embodiment, to ensure the stability of the structure, the cross-section of the connecting column is trapezoidal. At the same time, to facilitate installation, the drill pipe outer tube 1 and the retainer 3 are installed by an interference fit. Specifically, the drill pipe outer tube 1 is heated to increase its inner diameter, and then the retainer 3 is installed inside. After the drill pipe outer tube 1 returns to normal, the interference fit between the drill pipe outer tube 1 and the retainer 3 is achieved.

[0019] Since the retainer 3 is to be installed with the drill pipe inner tube 2, the retainer 3 is set close to both ends of the drill pipe outer tube 1, so that the drill pipe inner tube 2 passes through the retainer 3.

[0020] Similarly, considering the installation of the drill pipe inner tube 2, in this embodiment, a fixing cap 4 is fitted onto the drill pipe inner tube 2, and the drill pipe inner tube 2 is mounted on the retainer 3 through the fixing cap 4. The fixing cap 4 is tubular in shape, with the portion inside the retaining ring being cylindrical and the portion extending outside the retaining ring being hexahedral, mainly to facilitate installation using a hexagonal wrench. In this embodiment, the fixing cap 4 and the retainer 3 are in contact connection, meaning they are in contact connection. Thus, under the action of external force, the drill pipe inner tube 2 can rotate. The purpose of this arrangement is mainly that both the drill pipe outer tube 1 and the drill pipe inner tube 2 are connected using a male-female connector method. In this embodiment, the drill pipe outer tubes 1 are connected using a nut connection, while the drill pipe inner tubes 2 are connected using a plug-in method. This rotating structure ensures that the two can be plugged in.

[0021] Meanwhile, the drill pipe inner tube 2 also needs to remove coal slurry from the borehole. For this purpose, a spiral blade 21 is installed on the side wall of the drill pipe inner tube 2, and the spiral blade 21 is positioned between the two retainers 3. In this way, the spiral blade 21 also has a certain limiting function, and now the drill pipe inner tube 2 moves between the two retainers 3.

[0022] To facilitate connection, the male end 22 of the drill pipe inner tube 2 has evenly distributed insertion protrusions 221 on its side wall. The cross-section of the insertion protrusions 221 is semi-circular. The other end of the drill pipe inner tube 2 is provided with a connector cap 23 that mates with the insertion protrusions 221. The connector cap 23 is the female end, and its inner wall is provided with a semi-circular groove. This ensures the stability of the connection between two adjacent drill pipe inner tubes 2, i.e., synchronous rotation.

[0023] In this way, during the installation process, the inner tubes 1 of the drill rods are threaded together, and the inner tubes 2 of the two drill rods are continuously inserted as they rotate, thus completing the connection.

[0024] The above description is merely a preferred embodiment of the present utility model and is not intended to limit the present utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present utility model without departing from the technical solution of the present utility model shall still fall within the protection scope of the technical solution of the present utility model.

Claims

1. A coal seam shielded pressure-relief drill pipe comprising a drill pipe outer tube and a drill pipe inner tube fitted outside the drill pipe outer tube, characterized in that, The outer tube of the drill pipe has a square cross-section and arc-shaped corners. A retainer is provided on the inner wall of the outer tube, and the retainer is located near both ends of the outer tube. The inner tube of the drill pipe passes through the retainer and is fitted with a fixing cap. The fixing cap is connected to the retainer, and the inner tube is mounted on the retainer through the fixing cap. A helical blade is provided on the side wall of the inner tube, and the helical blade is located between the two retainers.

2. The coal seam shielded pressure-relief drill pipe according to claim 1, characterized in that, The inner tube of the drill pipe has evenly distributed insertion protrusions on the side wall of one end, and the cross-section of the insertion protrusions is semi-circular. The other end of the inner tube of the drill pipe is provided with a plug cap that mates with the insertion protrusions.

3. The coal seam shielded pressure-relief drill pipe of claim 2, wherein, The retainer is interference-fitted to the outer tube of the drill pipe.

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