High pressure water strand for coal mine drilling

Abstract

This utility model discloses a high-pressure water braid for coal mine drilling, comprising a fixed body, a rotating body, and bearings arranged coaxially. The fixed body includes a protective shell, an end cap, a high-pressure seal, an O-ring, and a lubricator. The top of the protective shell is fixed to the end cap by threads, and a high-pressure seal is provided at the bottom of the protective shell. The O-ring is installed inside the end cap, and the lubricator is installed on the end cap. The rotating body includes an inner shaft and a bearing support pad. The bearings include rolling bearings and flat bearings. The inner shaft is located inside the protective shell and extends through the end cap. The middle part of the inner shaft is installed to the protective shell through rolling bearings and flat bearings. It adopts a split design, and the fixed body and the rotating body are connected by bearings. This allows the fixed body and the rotating body to rotate relative to each other while slightly moving relative to each other in the axial direction of the inner shaft, thereby compressing the internal oil injection cavity and generating reverse pressure, thus reducing the axial force on the bearing and achieving flexible rotation under high pressure conditions.

Description

Technical Field

[0001] This utility model relates to the field of coal seam permeability enhancement technology, specifically to a high-pressure water braid for coal mine drilling. Background Technology

[0002] With the development of my country's coal industry and the increasing demand for coal in the national economy, coal production has been continuously increasing. Innovation in coal mining technology has become a crucial factor restricting coal mining, especially the development of gas extraction technology, which further constrains the increase in coal production. Currently, commonly used methods to improve gas extraction efficiency include high-pressure hydraulic perforation and high-pressure hydraulic slotting. This involves first drilling holes in the coal seam with a drilling rig, and then using high-pressure water to flush out large cavities in the drilled coal seam, facilitating gas discharge. However, with the increasing mining depth of coal seams in recent years, the corresponding geological conditions have become increasingly poor, and the "three soft" characteristics of coal seams have become more pronounced, increasing the difficulty and efficiency of gas extraction. Consequently, higher demands are being placed on the development of high-pressure hydraulic perforation and high-pressure hydraulic slotting technologies.

[0003] To achieve the desired drilling effect, the drill pipe must continue rotating after high-pressure water jetting. The high-pressure water braid supplying the water also needs to withstand sufficient medium pressure to deliver water from the supply pipe to the drill pipe. In recent years, the required medium pressure for the high-pressure water braid has increased from 0-50 MPa to 70-100 MPa. However, current high-pressure water braids can only withstand medium pressures up to 50 MPa, which is insufficient for achieving the desired hydraulic drilling effect. Furthermore, when subjected to pressures of 70-100 MPa, the large axial force on the internal bearings makes rotation difficult and leads to rapid wear, requiring frequent replacements. Moreover, existing high-pressure water braids have various auxiliary structures, resulting in a complex structure that increases the load on the drill pipe rotation and reduces the efficiency of high-pressure water delivery.

[0004] Therefore, there is a need to provide a high-pressure water jet for coal mine drilling. Utility Model Content

[0005] To address the problems existing in the prior art, this utility model provides a high-pressure water braid for coal mine drilling, which can deliver high-pressure water from the water supply pipe to the drill rod while maintaining the rotation of the drill rod, and at the same time solves the technical problems of low medium carrying capacity and large wear of parts in existing high-pressure water braids.

[0006] To achieve the above objectives, this utility model is implemented through the following technical solution: a high-pressure water jet for coal mine drilling, comprising a fixed body, a rotating body, and bearings arranged coaxially. The fixed body includes a protective shell, an end cap, a high-pressure seal, an O-ring, and a lubricator. The top of the protective shell is fixed to the end cap by threads, and a high-pressure seal is provided at the bottom of the protective shell. The O-ring is installed inside the end cap, and the lubricator is installed on the end cap. The rotating body includes an inner shaft and a bearing support pad. The bearings include rolling bearings and flat bearings. The inner shaft is located inside the protective shell and extends through the end cap. The middle part of the inner shaft is installed with the protective shell through the rolling bearing and the flat bearing. The rolling bearing and the flat bearing are separated by the bearing support pad. The bottom of the inner shaft is sealed to the protective shell by a sleeved high-pressure seal. The upper part of the inner shaft is sealed to the end cap by a sleeved O-ring. The inner wall of the end cap, the outer circle of the inner shaft, and the two O-rings form an oil injection cavity. The lubricator injects lubricating grease or hydraulic oil into the oil injection cavity through the oil passage of the end cap.

[0007] Preferably, the end cap is sealed with double-layered and separately arranged O-rings for the inner shaft seal.

[0008] Preferably, the area of ​​the oil injection cavity that exerts pressure on the inner shaft is much larger than the area of ​​the medium pressure exerted on the inner bearing.

[0009] Preferably, the rotating body undergoes slight relative movement in the axial direction relative to the fixed body, thereby squeezing the oil injection cavity and the plane bearing to generate reverse pressure, so as to balance the medium pressure borne by the high-pressure water braid.

[0010] Preferably, the O-ring is a common O-ring made of any one of nitrile rubber, fluororubber, or EPDM rubber.

[0011] In summary, this utility model provides a high-pressure water braid for coal mine drilling. The beneficial effects of this utility model are as follows: This utility model adopts a split design, and the fixed body and rotating body are connected by bearings. This allows the fixed and rotating bodies to rotate relative to each other while experiencing slight relative movement in the axial direction of the inner shaft. This compresses the internal oil injection cavity, generating reverse pressure, thereby reducing the axial force on the bearings and achieving flexible rotation under high-pressure working conditions. In conclusion, this utility model can adapt to drill rod rotation, withstand large media pressures, and has the advantages of convenient connection, wear resistance, and good sealing performance. Attached Figure Description

[0012] Figure 1 This is a schematic diagram of the structure of this utility model; In the diagram: 1. Protective housing, 2. End cap, 3. Inner shaft, 4. Bearing support pad, 5. Rolling bearing, 6. Surface bearing, 7. High-pressure seal, 8. O-ring, 9. Oiler. Detailed Implementation

[0013] The present invention will be further described below with reference to the accompanying drawings.

[0014] like Figure 1 As shown: This utility model is a high-pressure water braid for coal mine drilling. The high-pressure water braid is connected to a high-pressure hose and a high-pressure sealed drill rod. It includes a fixed body, a rotating body, and a bearing arranged coaxially. The fixed body and the rotating body are mutually referenced. The fixed body is connected to the high-pressure hose, and the rotating body is connected to the high-pressure sealed drill rod. The fixed body includes a protective housing 1, an end cap 2, a high-pressure seal 7, an O-ring 8, and a lubricator 9. The top of the housing 1 is fixed to the end cap 2 by threads. The bottom of the housing 1 is provided with a high-pressure seal 7. The O-ring 8 is installed inside the end cap 2. The lubricator 9 is installed on the end cap 2. The rotating body includes an inner shaft 3 and a bearing support pad 4. The bearings include rolling bearings 5 ​​and flat bearings 6. The inner shaft 3 is located inside the housing 1 and extends out through the end cap 2. The middle part of the inner shaft 3 is installed with the housing 1 through the rolling bearings 5 ​​and the flat bearings 6. The rolling bearings 5 ​​and the flat bearings 6 are separated by the bearing support pad 4. The bottom of the inner shaft 3 is sealed to the housing 1 by the high-pressure seal 7. The upper part of the inner shaft 3 is sealed to the end cap 2 by the O-ring 8. The inner wall of the end cap 2, the outer circle of the inner shaft 3, and the two O-rings 8 form an oil filling cavity. The lubricator 9 adds lubricating grease or hydraulic oil to the oil filling cavity through the oil passage of the end cap 2.

[0015] The operating principle is as follows: During installation, grease or hydraulic oil is added to the oil filling cavity formed by the inner wall of the end cap 2, the outer circle of the inner shaft 3, and the two O-rings 8 through the oil filler 9; during use, the rotating body moves slightly relative to the fixed body in the axial direction, thereby squeezing the oil filling cavity and the plane bearing 6, generating reverse pressure to balance the medium pressure borne by the high-pressure water braid; since the area of ​​the oil filling cavity exerting pressure on the inner shaft 3 is much larger than the area of ​​the medium pressure borne by the inner shaft 3, the pressure in the oil filling cavity is much smaller than the medium pressure, so ordinary O-rings 8 can be used here; at the same time, since the axial pressure borne by the bearing is 0 or small, the rotating body still rotates relatively flexibly.

[0016] In at least one embodiment, the inner shaft 3 is sealed with double-layered and separately arranged O-rings 8 inside the end cap 2, so as to form an oil injection cavity through the two O-rings 8, the inner wall of the end cap 2 and the outer circle of the inner shaft 3.

[0017] In at least one embodiment, the O-ring 8 is a common O-ring made of any one of nitrile rubber, fluororubber, or EPDM rubber.

[0018] The embodiments described in this utility model are for illustrative purposes only and do not constitute a limitation on the scope of the claims. Other substantially equivalent substitutions that can be conceived by those skilled in the art are all within the protection scope of this utility model.

Claims

1. A high pressure water jet for use in drilling coal mines, characterised in that, The device includes a fixed body, a rotating body, and bearings arranged coaxially. The fixed body includes a protective housing (1), an end cap (2), a high-pressure seal (7), an O-ring (8), and a lubricator (9). The top of the protective housing (1) is fixed to the end cap (2) by threads. A high-pressure seal (7) is provided at the bottom of the protective housing (1). The O-ring (8) is installed inside the end cap (2), and the lubricator (9) is installed on the end cap (2). The rotating body includes an inner shaft (3) and a bearing support pad (4). The bearings include a rolling bearing (5) and a flat bearing (6). The inner shaft (3) is located inside the protective housing (1) and... Extending out through the end cap (2), the middle part of the inner shaft (3) is installed with the protective housing (1) through the rolling bearing (5) and the flat bearing (6). The rolling bearing (5) and the flat bearing (6) are separated by the bearing support pad (4). The bottom of the inner shaft (3) is sealed to the protective housing (1) through the sleeve high pressure seal (7). The upper part of the inner shaft (3) is sealed to the end cap (2) through the sleeve O-ring (8). The inner wall of the end cap (2) and the outer circle of the inner shaft (3) and the two O-rings (8) form an oil filling cavity. The oil filler (9) adds lubricating grease or hydraulic oil to the oil filling cavity through the oil passage of the end cap (2).

2. The high pressure water jet according to claim 1, characterized in that, The end cap (2) is sealed to the inner shaft (3) by a double-layered and separately set O-ring (8).

3. The high-pressure water jet for coal mine drilling according to claim 1, characterized in that, The area of ​​the oil injection chamber that exerts pressure on the inner shaft (3) is much larger than the area of ​​the medium pressure that the inner shaft (3) bears.

4. The high-pressure water jet for coal mine drilling according to claim 1, characterized in that, The rotating body moves slightly relative to the stationary body in the axial direction, thereby squeezing the oil injection cavity and the plane bearing (6) to generate reverse pressure to balance the medium pressure borne by the high-pressure water braid.

5. A high-pressure water jet for coal mine drilling according to claim 3, characterized in that, The O-ring (8) is a common O-ring made of any one of nitrile rubber, fluororubber or EPDM rubber.

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