A double tube single action coring device

Abstract

The utility model discloses a kind of double-tube single-action core taking devices, including double-tube single-action device, drill, inner tube joint and outer tube joint, double-tube single-action device includes outer tube and inner tube, inner tube part is inside outer tube, another part is stretched from outer tube front end, outer tube joint is connected with outer tube from double-tube single-action device rear end, inner tube joint is connected with inner tube from double-tube single-action device front end, drill is connected with outer tube front end, inner tube joint rear portion is connected with main shaft by adjusting shaft rear portion, the front and rear sections of main shaft are respectively symmetrically provided with bearing group, the bearing group includes the radial bearing between plane bearing and plane bearing, bearing outer sleeve is connected outside bearing group, lubricating hole that is directly opposite radial bearing is formed on bearing outer sleeve, oil cup is installed in lubricating hole and injects lubricating oil towards radial bearing. The present application improves the stability and durability of the mechanism, and the inner tube is directly connected with the half-combination tube type double-tube clamp spring seat, improving the working stability of the inner tube.

Description

Technical Field

[0001] This utility model belongs to the field of geological drilling and coring, specifically relating to a dual-tube single-action coring device. Background Technology

[0002] In core drilling of complex formations such as fractured, loose, water-sensitive, and alternating layers of soft and hard materials, single-action double-tube drilling has become the preferred technology for ensuring core quality and improving drilling efficiency. In a single-action double-tube drill bit, the inner tube remains stationary while the outer tube drives the drill bit to rotate. Flushing fluid flows downwards through the annular gap between the inner and outer tubes, avoiding direct scouring of the core. This increases the core recovery rate in fractured, loose, and water-sensitive formations from the conventional 50%–60% to over 85%, and also enables successful core recovery in the lower layers such as fault breccia and weak interlayers. However, the single-action mechanism in ordinary single-action double-tube drill bits has the following problems: 1. Traditional single-action mechanisms typically use two bearings, upper and lower. After a period of use, bearing wear can easily lead to misalignment of the inner tube, hindering the normal entry of the core into the inner tube. 2. Adding lubricant to the traditional single-action mechanism requires disassembly, which is time-consuming and labor-intensive. 3. The connections between the original mechanism's short section, the inner tube, and the retaining ring seat are all sleeve connections, which are prone to misalignment due to machining inaccuracies, hindering the normal entry of the core into the inner tube. Utility Model Content

[0003] The purpose of this invention is to provide a mechanism that can improve stability and durability, facilitate lubrication, and increase efficiency.

[0004] To achieve the above objectives, the technical solution of this utility model is as follows: a double-tube single-action coring device, comprising a double-tube single-action device, a drill bit, an inner tube connector, and an outer tube connector. The double-tube single-action device includes an outer tube and an inner tube, with one part of the inner tube inside the outer tube and the other part extending from the front end of the outer tube. The outer tube connector is connected to the outer tube from the rear end of the double-tube single-action device, and the inner tube connector is connected to the inner tube from the front end of the double-tube single-action device. A reamer is connected to the front end of the outer tube from the front end of the double-tube single-action device. The drill bit is connected to the front end of the reamer. The rear part of the inner tube connector is connected to the main shaft via the rear part of an adjusting shaft. Bearing assemblies are symmetrically arranged at the front and rear sections of the main shaft. Each bearing assembly includes a plane bearing and a radial bearing. Two radial bearings are arranged between two plane bearings. Each bearing assembly is connected to a bearing sleeve. A lubrication hole is opened on the bearing sleeve, facing the radial bearing. An oil cup is installed in the lubrication hole and injects lubricating oil towards the radial bearing.

[0005] The inner tube of the dual-tube single-action device is provided with a retaining ring seat on the front inner side, and a retaining ring is provided on the inner side of the retaining ring seat. The retaining ring seat and the retaining ring are in a tapered fit.

[0006] An elastic clamp is provided between the outer wall of the inner tube and the inner wall of the outer tube. The outer wall of the inner tube has an annular protrusion near the front of the inner tube. The centering ring is sleeved on the outer wall of the inner tube and is engaged between the annular protrusion and the front of the inner tube.

[0007] The planar bearing at the rear section of the main shaft is fixed by a lock nut. The middle part of the bearing outer sleeve is clearance-fitted with the main shaft. The opposite ends of the two bearing outer sleeves are respectively connected to sealing caps. A sealing ring is assembled between the sealing caps and the main shaft. The opposite ends of the two bearing outer sleeves are constructed as a reduced diameter section. The middle of the front end of the outer tube joint and the middle of the rear end of the adjusting shaft are respectively provided with a receiving cavity and a blind hole, which can accommodate the lock nut and the main shaft. The receiving cavity and the blind hole are respectively threaded to the reduced diameter section of the bearing outer sleeve.

[0008] The adjusting shaft consists of two parts, front and rear. The front end of the adjusting shaft extends into the inner tube. The adjusting shaft and the inner tube are fixedly connected by the inner tube joint and the adjusting nut. The inner tube joint is connected to the rear part of the inner tube of the double tube single-action device. The middle of the rear part of the adjusting shaft has a blind hole with a combination of conical and cylindrical shapes that opens axially.

[0009] The front part of the adjusting shaft is also provided with a cylindrical hollow area along the axis. The front end of the cylindrical hollow area is connected to the steel ball receiving area at the front end of the adjusting shaft. A steel ball is provided in the steel ball receiving area. The diameter of the steel ball is smaller than the inner diameter of the port of the cylindrical hollow area. A hollow plug bolt is installed at the front port of the steel ball receiving area. The rear end of the cylindrical hollow area is connected to the outer wall of the front part of the adjusting shaft through a radial hole. The radial hole is set radially along the front part of the adjusting shaft.

[0010] The outer pipe joint consists of two parts: the front outer wall of the rear part of the outer pipe joint is connected to the inner wall of the outer pipe, the rear outer wall of the rear part of the outer pipe joint is connected to the inner wall of the sand settling pipe, and the middle of the rear part is axially opened to form a pipe body with a cylindrical cavity; the middle of the front part of the outer pipe joint has a receiving cavity facing the rear end of the single-action device.

[0011] The outer pipe joint is equipped with a retrieval head and a one-way valve in the pipe body at the rear. The one-way valve includes a valve core and a valve body. There is a gap between the front end of the retrieval head and the valve body. The valve core is installed between the front end of the retrieval head and the valve body and can move along the axis. The retrieval head and the valve body respectively have a through hole and a valve core hole arranged along the axis. A spring is installed in the valve core hole of the valve body. The spring pushes the valve core towards the retrieval head side. The front end of the valve core hole is connected to the cylindrical cavity at the rear of the outer pipe joint through an outlet hole.

[0012] The rear end of the retrieval head extends into the sedimentation pipe and is connected to the sand separation pipe. The rear end of the sedimentation pipe is connected to the water distribution cover.

[0013] Beneficial effects: This utility model solves the problem of misalignment caused by easy wear by setting multiple sets of bearings, which increases the stability of the single-action mechanism; (2) sets an oil injection hole to facilitate the addition of grease for lubrication, which reduces wear and improves the durability of the device; (3) adopts the direct connection between the inner tube and the semi-closed tube double tube snap ring seat, which provides stability when the inner tube is working. Attached Figure Description

[0014] Figure 1This is a schematic diagram of the structure of a double-tube single-acting device; Figure 2 This is a schematic diagram of the overall structure of a dual-tube single-action coring device. Figure 3 for Figure 2 A schematic diagram of the assembled adjusting shaft, inner tube joint, and rear end of the inner tube; Figure 4 for Figure 2 A schematic diagram of the structure of the assembled water distribution cover, sand settling pipe, sand separating pipe, and external pipe joint; Figure 5 This is a schematic diagram of an elastic clamp structure; Figure 6 This is a schematic diagram of the central ring structure. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model. Furthermore, the technical features involved in the various embodiments of the present utility model described below can be combined with each other as long as they do not conflict with each other.

[0016] like Figure 1-6 As shown, a dual-tube single-action coring device includes a dual-tube single-action device, a drill bit 31, and an outer tube connector 8. The dual-tube single-action device includes an outer tube 24 and an inner tube 25. Part of the inner tube 25 is inside the outer tube 24, and the other part extends from the front end of the outer tube 24. The outer tube connector 8 connects to the outer tube 24 from the rear end of the dual-tube single-action device, and the inner tube connector 21 connects to the inner tube 25 from the front end of the dual-tube single-action device. A reamer 27 connects to the front end of the outer tube 24 from the front end of the dual-tube single-action device. Since the drill bit diameter is generally 1-5mm larger than the drill string diameter, installing a reamer between the drill bit and the drill string can maintain a stable drilling diameter and extend the service life of the drill string. The drill bit 31 is connected to the front end of the reamer 27. An elastic clamp 26 is provided between the outer wall of the inner tube 25 and the inner wall of the outer tube 24 to ensure that the inner tube 25 is aligned.

[0017] The inner tube 25 of the double-tube single-action device is provided with a retaining ring seat 29 at the front and a retaining ring 30 is provided on the inner side of the retaining ring seat 29. The retaining ring seat 29 and the retaining ring 30 are tapered, which facilitates the insertion of the core sample during drilling and ensures the stability of the inner tube. The center ring 28 is sleeved on the outer wall of the inner tube and is engaged between the protrusion of the inner tube 25 and the retaining ring seat 29, which can limit the inner tube and improve the concentricity of the inner tube.

[0018] The rear of the inner tube 25 of the double-tube single-action device is connected to the adjusting shaft 19. The front end of the adjusting shaft 19 extends into the inner tube 25. The adjusting shaft 19 and the inner tube 25 are fixedly connected by the inner tube connector 21 and the adjusting nut 20. The inner tube connector 21 is connected to the rear of the inner tube 25 of the double-tube single-action device. A cylindrical hollow area 33 is provided along the axis at the front of the adjusting shaft. The front end of the cylindrical hollow area 33 is connected to the steel ball receiving area at the front end of the adjusting shaft 19. A steel ball 22 is provided in the steel ball receiving area. The diameter of the steel ball is smaller than the inner diameter of the port of the cylindrical hollow area 33. A hollow plug bolt 23 is installed at the front port of the steel ball receiving area. The rear end of the cylindrical hollow area 33 is connected to the front outer wall of the adjusting shaft 19 through a radial hole 34. The radial hole 34 is arranged radially along the front of the adjusting shaft 19. During the coring process, the water flow also enters the inner tube along with the cored sample. The water flow in the latter part of the cored sample enters the adjusting shaft 19 through the hollow of the plug bolt 23, passes through the steel ball receiving area and the cylindrical hollow area 33 of the adjusting shaft 19 in sequence, and then flows out from the radial hole 34 into the gap between the inner tube and the outer tube.

[0019] A blind hole 32 with a combination of conical and cylindrical shapes is provided in the middle of the rear part of the adjusting shaft 19, and it is connected to the main shaft 18. One end of the main shaft 18 extends into the blind hole 32 in the rear part of the adjusting shaft 19. Bearing assemblies are symmetrically arranged in the front and rear sections of the main shaft 18. The bearing assembly includes a plane bearing 12 and a radial bearing 13. The radial bearing 13 is arranged between the two plane bearings 12. The plane bearing 13 is fixed by a locking nut 9. A bearing outer sleeve 15 is connected to the outside of the bearing assembly. The middle part of the bearing outer sleeve 15 is clearance-fitted with the main shaft 18. A sealing cover 17 is connected to the opposite ends of the two bearing outer sleeves 15. A sealing ring 16 is assembled between the sealing cover 17 and the main shaft 18. The sealing ring 16 is a Y-type sealing ring. The opposite ends of the two bearing outer sleeves 15 are constructed as a reduced diameter section. The bearing outer sleeve 15 has a lubrication hole facing the radial bearing 13. The oil cup 14 is installed in the lubrication hole and injects lubricating oil into the radial bearing 13. The lubricating oil can reach the plane bearing 12 along the gap between the bearing outer sleeve 15 and the main shaft 18 to lubricate the plane bearing 12.

[0020] Furthermore, the blind hole 32 of the adjusting shaft 19 can accommodate the second locking nut 9b at the front end of the double-tube single-action device and the reduced diameter section at the front end of the second single-action bearing sleeve 15b. The blind hole 32 is threadedly connected to the reduced diameter section at the front end of the second single-action bearing sleeve 15b. The front end of the outer tube connector 8 has a receiving cavity facing the rear end of the single-action device. The receiving cavity can accommodate the first locking nut 9a at the rear end of the double-tube single-action device and the reduced diameter section at the rear end of the first single-action bearing sleeve 15a. The inner wall of the receiving cavity is threadedly connected to the reduced diameter section at the rear end of the single-action bearing sleeve 15a at the rear end of the single-action device. This restricts the range of forward and backward movement of the main shaft 18 during the core extraction process, so that the main shaft 18 and the retaining spring 30 can hold the core sample and remove it from the ground.

[0021] Furthermore, the outer pipe joint 8 is composed of two parts, front and rear. The outer wall of the front end of the rear part of the outer pipe joint is connected to the inner wall of the outer pipe 24, and the outer wall of the rear end of the outer pipe joint 8 is connected to the inner wall of the sand settling pipe 2. The middle of the rear end opens axially to form a pipe body with a cylindrical cavity 35. The front end of the grooved rear end of the outer pipe joint is connected to two inclined wall holes 36 as a waterway. The middle of the front end of the outer pipe joint 8 is provided with a receiving cavity facing the rear end of the single-action device. The receiving cavity can accommodate the rear end of the main shaft 18 and the locking nut 9.

[0022] The rear part of the outer pipe joint 8 is equipped with a retrieval head 4 and a one-way valve. The one-way valve includes a valve core 5 and a valve body 6. There is a gap between the front end of the retrieval head 4 and the valve body 6. The valve core 5 is installed between the front end of the retrieval head 4 and the valve body 6 and can move along the axis. The retrieval head 4 and the valve body 6 respectively have a through hole 37 and a valve core hole 38 arranged along the axis. A spring 7 is installed in the valve core hole 38 of the valve body 6. The spring 7 pushes the valve core 5 towards the retrieval head 4. The front end of the valve core hole 38 is connected to the cylindrical cavity 35 in the rear part of the outer pipe joint 8 through the lead-out hole 39.

[0023] The rear end of the retrieval head 4 extends into the sand settling pipe 2 and is connected to the sand isolation pipe 3. The rear end of the sand settling pipe 2 is connected to the water distribution cap 1. The sand isolation pipe 3 and the sand settling pipe 2 can reduce the sand content in the drilling water. After the water flows from the middle of the water distribution cap 1 into the hole on the sand isolation pipe 3, it flows through the sand isolation pipe 3, enters the annular gap between the inner and outer pipes through the wall hole 36 of the outer pipe joint 8, and flows into the front end. It is discharged in front of the retaining ring 30 and the drill bit 31, part of which returns to the inner pipe 25, and part of which returns upward from the annular gap between the core sampling device and the hole wall.

[0024] While the specific embodiments of this disclosure have been described above in conjunction with the accompanying drawings, this is not intended to limit the scope of protection of this disclosure. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art without creative effort based on the technical solutions of this disclosure are still within the scope of protection of this disclosure.

Claims

1. A double-tube single-action coring device, comprising a double-tube single-action device, a drill bit (31), an inner tube connector (21), and an outer tube connector (8), wherein the double-tube single-action device comprises an outer tube (24) and an inner tube (25), a portion of the inner tube (25) is inside the outer tube (24), and the other portion extends from the front end of the outer tube (24); the outer tube connector (8) is connected to the outer tube (24) from the rear end of the double-tube single-action device; the inner tube connector (21) is connected to the inner tube (25) from the front end of the double-tube single-action device; a reamer (27) is connected to the front end of the outer tube (24) from the front end of the double-tube single-action device; and the drill bit (31) is connected to the front end of the reamer (27). The device is characterized in that... The rear part of the inner tube connector (21) is connected to the main shaft (18) via the rear part of the adjusting shaft (19). The front and rear sections of the main shaft (18) are respectively symmetrically provided with bearing groups. Each bearing group includes a plane bearing (12) and a radial bearing (13). The two radial bearings (13) are arranged between the two plane bearings (12). Each bearing group is connected to a bearing sleeve (15). The bearing sleeve (15) is provided with a lubrication hole facing the radial bearing (13). The oil cup (14) is installed in the lubrication hole and injects lubricating oil towards the radial bearing (13).

2. The dual-tube single-action coring device according to claim 1, characterized in that, The inner tube (25) of the double-tube single-action device is provided with a snap ring seat (29) on the front inner side, and a snap ring (30) is provided on the inner side of the snap ring seat (29). The snap ring seat (29) and the snap ring (30) are in a tapered fit.

3. The dual-tube single-action coring device according to claim 2, characterized in that, An elastic clamp (26) is provided between the outer wall of the inner tube (25) and the inner wall of the outer tube (24). The outer wall of the inner tube (25) is provided with an annular protrusion near the front of the inner tube (25). The centering ring (28) is sleeved on the outer wall of the inner tube (25) and is clamped between the annular protrusion of the inner tube (25) and the front of the inner tube (25).

4. The dual-tube single-action coring device according to claim 1, characterized in that, The planar bearing (12) of the rear section of the main shaft (18) is fixed by a locking nut (9). The middle part of the bearing sleeve (15) is clearance-fitted with the main shaft (18). The opposite ends of the two bearing sleeves (15) are respectively connected to sealing caps (17). A sealing ring (16) is assembled between the sealing cap (17) and the main shaft (18). The opposite ends of the two bearing sleeves (15) are constructed as a reduced diameter section. The middle part of the front end of the outer tube joint (8) and the middle part of the rear end of the adjusting shaft (19) are respectively provided with a receiving cavity and a blind hole (32) to accommodate the locking nut (9) and the main shaft (18). The receiving cavity and the blind hole (32) are respectively threaded to the reduced diameter section of the bearing sleeve (15).

5. The dual-tube single-action coring device according to claim 1, characterized in that, The adjusting shaft (19) consists of two parts, front and rear. The front end of the adjusting shaft (19) extends into the inner tube (25). The adjusting shaft (19) and the inner tube (25) are fixedly connected by the inner tube joint (21) and the adjusting nut (20). The inner tube joint (21) is connected to the rear part of the inner tube (25) of the double tube single action device. The middle part of the rear part of the adjusting shaft (19) has a blind hole (32) with a combination of conical and cylindrical shape.

6. The dual-tube single-action coring device according to claim 5, characterized in that, The front part of the adjusting shaft (19) is also provided with a cylindrical hollow area (33) along the axis. The front end of the cylindrical hollow area (33) is connected to the steel ball receiving area at the front end of the adjusting shaft (19). A steel ball (22) is provided in the steel ball receiving area. The diameter of the steel ball is smaller than the inner diameter of the port of the cylindrical hollow area (33). A hollow plug bolt (23) is installed at the front port of the steel ball receiving area. The rear end of the cylindrical hollow area (33) is connected to the front outer wall of the adjusting shaft (19) through a radial hole (34). The radial hole (34) is set radially along the front of the adjusting shaft (19).

7. The dual-tube single-action coring device according to claim 1, characterized in that, The outer pipe joint (8) consists of two parts, front and rear. The outer wall of the front end of the rear part of the outer pipe joint is connected to the inner wall of the outer pipe (24), and the outer wall of the rear end of the outer pipe joint (8) is connected to the inner wall of the sand settling pipe (2). The middle part of the rear end opens along the axis to form a pipe body with a cylindrical cavity (35). The middle part of the front end of the outer pipe joint (8) is provided with a receiving cavity facing the rear end of the single-action device.

8. A dual-tube single-action coring device according to claim 7, characterized in that, The outer pipe joint (8) is equipped with a retrieval head (4) and a one-way valve in the pipe body at the rear. The one-way valve includes a valve core (5) and a valve body (6). There is a gap between the front end of the retrieval head (4) and the valve body (6). The valve core (5) is installed between the front end of the retrieval head (4) and the valve body (6) and can move along the axis. The retrieval head (4) and the valve body (6) respectively have a through hole (37) and a valve core hole (38) arranged along the axis. A spring (7) is installed in the valve core hole (38) of the valve body (6). The spring (7) pushes the valve core (5) towards the retrieval head (4). The front end of the valve core hole (38) is connected to the cylindrical cavity (35) at the rear of the outer pipe joint (8) through the lead-out hole (39).

9. A dual-tube single-action coring device according to claim 8, characterized in that, The rear end of the retrieval head (4) extends into the sedimentation pipe (2) and is connected to the sand separation pipe (3). The rear end of the sedimentation pipe (2) is connected to the water distribution cover (1).

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