Multi-impeller passive-rotating-stirring-type rotary drilling rig for open caissons

Abstract

A multi-impeller passive-rotating-stirring-type rotary drilling rig for open caissons includes a hollow main drill pipe, a drill bit, four cutting edges, four impeller shafts, four passive impellers and a rotation bracket. Through being uniformly distributed at a peripheral of the drilling rig, four passive impellers contact with a hole wall of a borehole during the drilling process for passively generating relative rotation opposite to the rotation direction of the drill bit, so as to accelerate sufficient mixing of silt and water for forming mud during the drilling process, thus enhancing the stirring effect of the drill bit on the mud. The present invention is able to improve the mud discharge efficiency without adding additional power, thus avoiding the blockage of the mud suction pipe and blockage or even breakage of the drill bit due to poor mud discharge during the drilling process.

Claims

1. A multi-impeller passive-rotating-stirring-type rotary drilling rig for open caissons, the drilling rig comprising a hollow main drill pipe (10), a drill bit (1), four cutting edges (3), four impeller shafts (6), four passive impellers (5) and a rotation bracket (9), wherein: the rotation bracket comprises (9) a central disk (12), four short beams (13) and four peripheral disks (14), wherein the four short beams (13) are uniformly distributed along a circumferential direction at an outer side of the central disk (12), one end of each of the four short beams (13) is connected with one of the four peripheral disks (14); the hollow main drill pipe (10) passes through the central disk (12) and is fixedly connected with the rotation bracket (9) through the central disk (12); a mud suction port (4), which penetrates through a front end and a rear end of the hollow main drill pipe (10), is provided at a bottom portion of the hollow main drill pipe (10; the drill bit (1) is coaxially fixed with the hollow main drill pipe (10) at a bottom end thereof; the four cutting edges (3) are uniformly distributed along a circumferential direction of the drill bit (1); multiple cutter teeth (2) are uniformly distributed along an outer side of a cutting direction of each of the four cutting edges (3); the four peripheral disks (14) are arranged opposite to the four cutting edges (3) up and down; two sealed end covers (7) are installed at a lower surface of each of the peripheral disks (14) and an upper surface of one of the four cutting edges (3) which is corresponding to the each of the peripheral disks (14). respectively, wherein the two sealed end covers (7) are opposite to each other up and down, each of which being configured to accommodating a seal ring therein; two beatings (8) are installed between one of the two sealed end covers (7), which is installed at the lower surface of the each of the peripheral disks (14), and the each of the peripheral disks (14), and between another of the two sealed end covers (7), which is installed at the upper surface of one of the four cutting edges (3) which is corresponding to the each of the peripheral disks (14), and the one of the four cutting edges (3) which is corresponding to the each of the peripheral disks (14), respectively; the each of the peripheral disks (14) is connected with the one of the four cutting edges (3) which is corresponding to the each of the peripheral disks (14) through the each of the impeller shafts (6); an upper end and a lower end of the each of the impeller shafts (6) respectively penetrate through the two sealed end covers (7), and then are respectively connected with the each of the peripheral disks (14) and the one of the four cutting edges (3) through the two bearings (8); each of the passive impellers (5), which is fixedly connected with a middle portion of the each of the impeller shafts (6), comprises six blades (15) centered on the each of the impeller shafts (6) and uniformly distributed along a circumferential direction of the each of the impeller shafts (6).

2. The multi-impeller passive-rotating-stirring-type rotary drilling rig for the open caissons according to claim 1, wherein during a drilling process, the cutting edges (3) and the rotation bracket (9) are driven to move axially by the hollow main drill pipe (10) while rotating around a central axis of the hollow main drill pipe (10), so as to drive the impeller shafts (6) to rotate around the central axis of the hollow main drill pipe (10); the blades (15) of the passive impellers (5) contact with a hole wall (11) during a rotation of the rotation bracket (9), the hole wall (11) provides the passive impellers (5) with a force opposite to a rotation direction of the rotation bracket (9), so that the passive impellers (5) produce a relative rotation opposite to a rotation direction of the rotation bracket (9).

3. The multi-impeller passive-rotating-stirring-type rotary drilling rig for the open caissons according to claim 1, wherein the sealed end covers (7) are configured to limit a radial displacement of the impeller shafts (6) and have a sealing effect.

4. The multi-impeller passive-rotating-stirring-type rotary drilling rig for the open caissons according to claim 1, wherein the hollow main drill pipe (10) is a hollow drill pipe, which is used to discharge mud formed by mixing silt and water in a process of drilling.

5. The multi-impeller passive-rotating-stirring-type rotary drilling rig for the open caissons according to claim 4, wherein the mud suction port (4) is elliptical and is communicated with the hollow mud discharge pipe which is located at the middle portion of the hollow main drill pipe (10); the mud suction port (4) and the passive impellers (5) are located at a same level.

6. The multi-impeller passive-rotating-stirring-type rotary drilling rig for the open caissons according to claim 1, wherein during a rotation of the passive impellers (5), a working range of an end of the blades (15) of the passive impellers (5) exceeds a maximum working range of the cutting edges (3).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] FIG. 1 is a front view of the present invention.

[0018] FIG. 2 is a top view of the present invention.

[0019] In the drawings, 1: drill bit; 2: cutter tooth; 3: cutting edge; 4: mud suction port; 5: passive impeller; 6: impeller shaft; 7: sealed end cover; 8: bearing; 9: rotation bracket; 10: hollow main drill pipe; 11: hole wall of borehole; 12: central disk; 13: short beam; 14: peripheral disk; 15: blade.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0020] The present invention is further described with reference to drawings and embodiments as follows.

[0021] Referring to FIG. 1, a multi-impeller passive-rotating-stirring-type rotary drilling rig for open caissons provided by the present invention is illustrated, which comprises a hollow main drill pipe 10, a drill bit 1, four cutting edges 3, four impeller shafts 6, four passive impellers 5 and a rotation bracket 9, wherein the rotation bracket 9 comprises a central disk 12, four short beams 13 and four peripheral disks 14, wherein the four short beams 13 are uniformly distributed along a circumferential direction at an outer side of the central disk 12, one end of each of the four short beams 13 is connected with one of the four peripheral disks 14; the hollow main drill pipe 10 passes through the central disk 12 and is fixedly connected with the rotation bracket 9 through the central disk 12; a mud suction port 4, which penetrates through a front end and a rear end of the hollow main drill pipe 10 is provided at a bottom portion of the hollow main drill pipe 10, that is, the mud suction port 4 penetrates through the hollow main drill pipe 10 along a radial direction thereof; the drill bit 1 is coaxially fixed with the hollow main drill pipe 10 at a bottom end thereof; the four cutting edges 3 are uniformly distributed along a circumferential direction of the drill bit 1; multiple cutter teeth 2 are uniformly distributed along an outer side of a cutting direction of each of the four cutting edges 3.

[0022] As shown in FIGS. 1 and 2, two sealed end covers 7 are installed at a lower surface of each of the peripheral disks 14 and an upper surface of one of the four cutting edges 3 which is corresponding to the each of the peripheral disks 14, respectively, wherein the two sealed end covers 7 are opposite to each other up and down, each of which being configured to accommodating a seal ring therein; two bearings 8 are installed between one of the two sealed end covers 7, which is installed at the lower surface of the each of the peripheral disks 14, and the each of the peripheral disks 14, and between another of the two sealed end covers 7, which is installed at the upper surface of one of the four cutting edges 3 which is corresponding to the each of the peripheral disks 14, and the one of the four cutting edges 3 which is corresponding to the each of the peripheral disks 14, respectively; the each of the four short beams 13 is connected with the one of the four cutting edges 3 which is corresponding to the each of the four short beams 13 through one of the impeller shafts 6; an upper end and a lower end of the one of the impeller shafts 6 respectively penetrate through the two sealed end covers 7, and then are respectively connected with the each of the peripheral disks 14 and the one of the four cutting edges 3 through the two bearings 8; each of the passive impellers 5, which is fixedly connected with a middle portion of the one of the impeller shafts 6, comprises six blades 15 centered on the one of the impeller shafts 6 and uniformly distributed along a circumferential direction of the one of the impeller shafts 6, wherein an angle between two adjacent blades 15 is 60°; the four peripheral disks 14 are arranged opposite to the four cutting edges 3 up and down.

[0023] As shown in FIG. 2, during the drilling process, a rotation direction of the four passive impellers 5 is opposite to a rotation direction of the four cutting edges 3, and a working range of an end of the blades 15 of the four passive impellers 5 slightly exceeds a maximum working range of the four cutting edges 3; so as to ensure that the four passive impellers 5 generate passive rotation.

Embodiment:

[0024] The drill bit 1 firstly drills into the soil during the drilling process, and maintains stable operation along the axial direction thereof during the subsequent drilling process; after the drill bit 1 penetrates through the soil, the four cutting edges 3 continue cutting underwater mucky soft soil, the cutter teeth 2 which uniformly distributed along the outer side of the cutting direction of the four cutting edges 3 cooperate with the four cutting edges 3 to enhance the cutting effect on the mucky soft soil; the rotation bracket 9 moves and rotates synchronously with the drill bit 1 during the drilling process.

[0025] During the drilling process, the impeller shafts 6 rotate with the rotation bracket 9 around a central axis of the drill bit 1, so that the passive impellers 5 contact with a hole wall 11 of a borehole; under double effects of the rotation of the rotation bracket 9 and the static hole wall 11, a relative rotation opposite to the rotation direction of the four cutting edges 3 is produced for enhancing the stirring effect on the silt; so as to improve the mud discharge efficiency during the drilling process, thereby improving the drilling efficiency, and reducing the occurrence of blockage of the mud suction pipe and blockage or even breakage of the drill bit due to poor mud discharge during the drilling process. Through the negative pressure generated by the rapid rotation between the hollow main drill pipe 10 and the borehole, the mud is sucked from the mud suction port 4, and finally through the hollow mud discharge pipe which is directly connected with a ground mud discharge device, the mud, which is formed by mixing water and the silt produced during the drilling process of caisson of intermediate tower of the bridge, is quickly discharged.