US20040089473A1 - Backreaming tool - Google Patents
Backreaming tool Download PDFInfo
- Publication number
- US20040089473A1 US20040089473A1 US10/258,755 US25875503A US2004089473A1 US 20040089473 A1 US20040089473 A1 US 20040089473A1 US 25875503 A US25875503 A US 25875503A US 2004089473 A1 US2004089473 A1 US 2004089473A1
- Authority
- US
- United States
- Prior art keywords
- drill string
- hammer
- pneumatic percussion
- compressed air
- percussion hammer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 238000009527 percussion Methods 0.000 claims abstract description 52
- 230000002441 reversible effect Effects 0.000 claims abstract description 11
- 230000000694 effects Effects 0.000 claims abstract description 5
- 238000013016 damping Methods 0.000 claims description 3
- 230000035939 shock Effects 0.000 claims description 3
- 238000000034 method Methods 0.000 claims description 2
- 239000011435 rock Substances 0.000 description 6
- 238000005553 drilling Methods 0.000 description 4
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 230000007935 neutral effect Effects 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- 229910000278 bentonite Inorganic materials 0.000 description 1
- 239000000440 bentonite Substances 0.000 description 1
- SVPXDRXYRYOSEX-UHFFFAOYSA-N bentoquatam Chemical compound O.O=[Si]=O.O=[Al]O[Al]=O SVPXDRXYRYOSEX-UHFFFAOYSA-N 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 230000006835 compression Effects 0.000 description 1
- 238000007906 compression Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000006260 foam Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 230000002093 peripheral effect Effects 0.000 description 1
Images
Classifications
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B4/00—Drives for drilling, used in the borehole
- E21B4/06—Down-hole impacting means, e.g. hammers
- E21B4/14—Fluid operated hammers
- E21B4/145—Fluid operated hammers of the self propelled-type, e.g. with a reverse mode to retract the device from the hole
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B7/00—Special methods or apparatus for drilling
- E21B7/28—Enlarging drilled holes, e.g. by counterboring
Definitions
- This invention relates to a backreaming tool for expanding a pilot bore produced by a drill string (set of drill rods joined together in line).
- Directional drilling in particular horizontal drilling, is used for producing bores which can accommodate pipes, utility lines and the like without the need for continuous excavation.
- a drill string is first used to drill a pilot bore. This bore is then enlarged so as to accommodate the required pipe, utility line etc. Enlarging is conveniently carried out by backreaming, which involves attaching a backreaming tool to the front end of the drill string which projects from the pilot bore, then pulling the drill rod in reverse direction through the pilot bore while rotating the drill string. As the backreaming tool is pulled through the pilot bore on the end of the drill string, it enlarges and compacts the wall of the bore.
- WO 99/19596 describes a directional drilling tool which is effective for directional drilling in rock. It also describes a backreaming tool in which a drill string is used in combination with percussion hammers.
- Percussion hammers also known as “moles” are known in the excavating field. They are commonly pneumatically operated, although other driving means are also known. It is also known for such percussion hammers to be drivable both forwardly and in reverse. An example of a percussion hammer with a reversing mechanism is shown in WO 91/19073.
- the present invention provides a backreming tool for expanding a pilot bore produced by a drill string, comprising a pneumatic percussion hammer in combination with a drill string, the drill string being rotatable and reversible through the pilot bore to effect backreaming by the pneumatic percussion hammer;
- the pneumatic percussion hammer has a first end adjacent the forward end of the drill string, and a second end remote from the drill string, a compressed air inlet pipe which passes through the first end and into a working cylinder of the hammer, whereby the working cylinder is capable of reciprocating and exerting hammer blows on an internal end surface of the hammer at the first end;
- the compressed air inlet pipe is connected to the forward end of the drill string, for supply of compressed air through the drill string into the air inlet pipe, and the compressed air inlet pipe is connected to the pneumatic percussion hammer in longitudinally slidable manner and in rotatably fixed manner, whereby the pneumatic percussion hammer is longitudinally adjustable relative to the drill string but is rotatable in accordance with rotation of the drill string;
- the position of the air inlet pipe relative to the working cylinder is such that the compressed air supply to the worldng cylinder is cut off or set in the neutral position when the hammer is longitudinally close to the end of the drill string, then restored as the hammer becomes more distant from the drill string, so as to prevent hammer blows falling on the forward end of the drill string.
- the invention also provides a method of expanding a pilot bore which has been produced by a drill string, which comprises connecting a pneumatic percussion hammer to the forward end of the drill string, supplying compressed air through the drill string to the pneumatic percussion hammer and reversing the drill string through the bore while rotating the drill string, so as to effect backreaming of the pilot bore by the pneumatic percussion hammer;
- a shock damping device between the hammer and the drill string may also be employed to further ensure that the hammer blows do not strike the drill string.
- FIG. 1 is a diagrammatic side view of a backreaming tool according to an embodiment of the invention, in which the compressed air supply to the pneumatic percussion hammer is cut off;
- FIG. 2 is a view corresponding to FIG. 1, in which the compressed air supply has been restored so as to start the hammer blow cycle;
- FIG. 3 is a view corresponding to FIG. 2, showing the position where the hammer blow occurs
- FIG. 4 is a side view of a backreaming tool according to an embodiment of the invention, showing external structural features
- FIG. 5 is a diagrammatic representation of heads of varying size which may be used in the backreaming tool
- FIGS. 6 and 7 are front and rear views of a head for use with the backreaming tool.
- FIGS. 8 and 9 represent further embodiments of head which may be used.
- FIGS. 1, 2 and 3 there is shown a pneumatic percussion hammer 1 which forms part of the backreaming tool according to the invention.
- the pneumatic percussion hammer 1 is itself of conventional design. It has a front end 2 and a rear end 3 , and is connected at its rear end 3 to the front end of the drill string (not shown).
- the pneumatic percussion hammer 1 is adapted to operate in “reverse” mode, i.e. the hammer blows are directed towards the rear end 3 .
- the invention is not restricted to this arrangement, and it would be possible to have the front end of the pneumatic percussion hammer in connection with the forward end of the drill string, and the pneumatic percussion hammer would then run in “forward” mode.
- the pneumatic percussion hammer has a hammer member 4 which is longitudinally slidable within a cylindrical chamber 5 .
- the hammer member 4 has an inner working cylinder 6 .
- Passages 7 communicate between the working cylinder 6 and the cylindrical chamber 5 .
- a compressed air inlet pipe 8 passes through the rear end 3 of the pneumatic percussion hammer and into the working cylinder 6 .
- the compressed air inlet pipe 8 is open at its forward end 9 so as to supply compressed air into the working cylinder 6 .
- the compressed air inlet pipe 8 is fixed at its rear end 10 to the forward end of the drill string, by a screw fitting or the like. Compressed air is supplied through the drill string and into the compressed air inlet pipe.
- the compressed air inlet pipe 8 has a longitudinally splined or keged collar intermediate its ends, which constitutes a male member in cooperation with an internally splined or keged female member which constitutes part of the rear end structure of the pneumatic percussion hammer.
- This splined or keged connection enables the compressed air inlet pipe 8 to be longitudinally slidable in relation to the pneumatic percussion hammer 1 .
- the pneumatic percussion hammer 1 is itself longitudinally adjustable relative to the drill string.
- the splined or keged connection between the compressed air inlet pipe 8 and the pneumatic percussion hammer 1 also means that rotation of the drill string will cause corresponding rotation of the pneumatic percussion hammer 1 .
- the front end portion of the compressed air inlet pipe 8 has a control valve 11 , which is a portion of increased diameter slidable within the bore of the working cylinder 6 .
- the control valve 11 is capable of covering the ends of the passages 7 so as to prevent communication between the working cylinder 6 and the cylindrical chamber 5 .
- the control valve 11 has travelled to the rear of the passages 7 , so that these passages are no longer covered, and compressed air can pass from the working chamber 6 through the passages 7 and into the cylindrical chamber 5 .
- the forward part of the hammer 4 has a side channel (not shown) permitting the compressed air to pass to the front part of the cylindrical chamber 5 .
- the compressed air then acts on the front surface of the hammer 4 , so as to drive it towards the rear, until the back surface of the hammer 4 impacts on the internal rear end of the cylindrical chamber 5 , as shown in FIG. 3.
- the cycle then repeats itself, with compressed air entering the working cylinder 6 through the forward end of the compressed air inlet pipe 8 .
- the resulting series of backward hammer blows causes the pneumatic percussion hammer 1 to begin to catch up with the drill string in its reverse passage through the pilot bore.
- the control valve 11 is again pushed in and the hammer cycle stops. In this way, hammer blows are prevented from being generated when the pneumatic percussion hammer is close to the drill string.
- a head 13 in the form of a ring shaped member is fitted on the rear end 3 of the pneumatic percussion hammer.
- the head 13 preferably has a flat rear face. This face may have hardened teeth 14 thereon, as shown in FIG. 4.
- the head 13 is a detachable member, and different size heads 13 may be provided as shown in FIG. 5 for different ground conditions and boring requirements.
- FIG. 4 also shows a screw connection 15 between the rear end 10 of the compressed air inlet pipe and the forward end 16 of the drill string. Also shown in FIG. 4 is an outer casing 17 for the pneumatic percussion hammer, which enables it to be used when water is present in the pilot bore, without ingress of water preventing proper operation. Alternatively, the hammer can be constructed with one-way air exhaust passages to prevent the inlet of water.
- FIGS. 6 to 9 show a variety of designs for the cutting head 13 .
- Passages may be provided, facing forward and rearward, and optionally at an angle to the axis. These permit air or fluids such as water, bentonite or foam to pass through the head. Larger passages may also be provided in the periphery, as shown at 18 , or closer to the centre, as shown at 19 , for spoil removal.
- the head can also be of a star shape as shown in FIG. 8. A reduced or non-interrupted peripheral surface causes powdered spoil to be forced by the air and compression into fissures, voids etc. in the ground, while the uninterrupted surface smooths the bore.
- the working face of the head 13 is preferably flat. This enables the greatest force to be applied to the ground, and in particular to rock and boulders. It ensures that the material is fully cut and powdered before being able to pass back over or through the head passages. This is in contrast to conventional reamers which are generally tapered and tend to jam in the ground or almost stall, and then grind themselves away when confronted with rock and boulders. They also tend to dislodge whole or parts of the rock which are passed through the blades or cutting wheels and lay in the bore, or they dislodge the bore completely causing collapse.
- the design of the present backreaming tool thus overcomes such problems.
Landscapes
- Engineering & Computer Science (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Mechanical Engineering (AREA)
- Earth Drilling (AREA)
Abstract
The invention provides a backreaming tool for expanding a pilot bore produced by a drill string, comprising a pneumatic perCussion hammer (1) in combination with a drill string, the drill string being rotatable and reversible through the pilot bore to effect backreaming by the pneumatic perCussion hammer. The pneumatic percussion hammer is longitudinally adjustable relative to the drill string. The arrangement is such that the compressed air supply to the working cylinder of the hammer is cut off when the hammer is longitudinally close to the end of the drill string, then restored as the hammer becomes more distant from the drill string.
Description
- This invention relates to a backreaming tool for expanding a pilot bore produced by a drill string (set of drill rods joined together in line).
- Directional drilling, in particular horizontal drilling, is used for producing bores which can accommodate pipes, utility lines and the like without the need for continuous excavation. A drill string is first used to drill a pilot bore. This bore is then enlarged so as to accommodate the required pipe, utility line etc. Enlarging is conveniently carried out by backreaming, which involves attaching a backreaming tool to the front end of the drill string which projects from the pilot bore, then pulling the drill rod in reverse direction through the pilot bore while rotating the drill string. As the backreaming tool is pulled through the pilot bore on the end of the drill string, it enlarges and compacts the wall of the bore.
- Various backreaming tools have been proposed, one example being shown in U.S. Pat. No. 5,921,331. While such tools may work satisfactorily in relatively soft ground, problems are encountered when the ground consists of continuous or intermittent rock, boulders etc. Such backreamers tend to jam in the ground or progress forward only very slowly, and therefore grind themselves away when confronted with rock and boulders.
- WO 99/19596 describes a directional drilling tool which is effective for directional drilling in rock. It also describes a backreaming tool in which a drill string is used in combination with percussion hammers.
- Percussion hammers (also known as “moles”) are known in the excavating field. They are commonly pneumatically operated, although other driving means are also known. It is also known for such percussion hammers to be drivable both forwardly and in reverse. An example of a percussion hammer with a reversing mechanism is shown in WO 91/19073.
- The present invention provides a backreming tool for expanding a pilot bore produced by a drill string, comprising a pneumatic percussion hammer in combination with a drill string, the drill string being rotatable and reversible through the pilot bore to effect backreaming by the pneumatic percussion hammer;
- wherein the pneumatic percussion hammer has a first end adjacent the forward end of the drill string, and a second end remote from the drill string, a compressed air inlet pipe which passes through the first end and into a working cylinder of the hammer, whereby the working cylinder is capable of reciprocating and exerting hammer blows on an internal end surface of the hammer at the first end;
- wherein the compressed air inlet pipe is connected to the forward end of the drill string, for supply of compressed air through the drill string into the air inlet pipe, and the compressed air inlet pipe is connected to the pneumatic percussion hammer in longitudinally slidable manner and in rotatably fixed manner, whereby the pneumatic percussion hammer is longitudinally adjustable relative to the drill string but is rotatable in accordance with rotation of the drill string;
- and wherein the position of the air inlet pipe relative to the working cylinder is such that the compressed air supply to the worldng cylinder is cut off or set in the neutral position when the hammer is longitudinally close to the end of the drill string, then restored as the hammer becomes more distant from the drill string, so as to prevent hammer blows falling on the forward end of the drill string.
- The invention also provides a method of expanding a pilot bore which has been produced by a drill string, which comprises connecting a pneumatic percussion hammer to the forward end of the drill string, supplying compressed air through the drill string to the pneumatic percussion hammer and reversing the drill string through the bore while rotating the drill string, so as to effect backreaming of the pilot bore by the pneumatic percussion hammer;
- wherein the supply of compressed air actuates the pneumatic percussion hammer so as to create hammer blows towards the drill string; and
- wherein the compressed air supply to the pneumatic percussion hammer is cut off or set to the neutral position when the hammer is longitudinally close to the end of the drill string, then restored as the hammer becomes more distant from the drill string, so as to prevent hammer blows falling on the forward end of the drill string.
- A shock damping device between the hammer and the drill string may also be employed to further ensure that the hammer blows do not strike the drill string.
- Reference is now made to the accompanying drawings, in which;
- FIG. 1 is a diagrammatic side view of a backreaming tool according to an embodiment of the invention, in which the compressed air supply to the pneumatic percussion hammer is cut off;
- FIG. 2 is a view corresponding to FIG. 1, in which the compressed air supply has been restored so as to start the hammer blow cycle;
- FIG. 3 is a view corresponding to FIG. 2, showing the position where the hammer blow occurs;
- FIG. 4 is a side view of a backreaming tool according to an embodiment of the invention, showing external structural features;
- FIG. 5 is a diagrammatic representation of heads of varying size which may be used in the backreaming tool;
- FIGS. 6 and 7 are front and rear views of a head for use with the backreaming tool; and
- FIGS. 8 and 9 represent further embodiments of head which may be used.
- Referring first to FIGS. 1, 2 and3, there is shown a
pneumatic percussion hammer 1 which forms part of the backreaming tool according to the invention. Thepneumatic percussion hammer 1 is itself of conventional design. It has afront end 2 and arear end 3, and is connected at itsrear end 3 to the front end of the drill string (not shown). In the embodiment shown, thepneumatic percussion hammer 1 is adapted to operate in “reverse” mode, i.e. the hammer blows are directed towards therear end 3. However, the invention is not restricted to this arrangement, and it would be possible to have the front end of the pneumatic percussion hammer in connection with the forward end of the drill string, and the pneumatic percussion hammer would then run in “forward” mode. - The pneumatic percussion hammer has a
hammer member 4 which is longitudinally slidable within acylindrical chamber 5. Thehammer member 4 has an inner workingcylinder 6.Passages 7 communicate between the workingcylinder 6 and thecylindrical chamber 5. A compressedair inlet pipe 8 passes through therear end 3 of the pneumatic percussion hammer and into the workingcylinder 6. The compressedair inlet pipe 8 is open at itsforward end 9 so as to supply compressed air into the workingcylinder 6. - The compressed
air inlet pipe 8 is fixed at itsrear end 10 to the forward end of the drill string, by a screw fitting or the like. Compressed air is supplied through the drill string and into the compressed air inlet pipe. - The compressed
air inlet pipe 8 has a longitudinally splined or keged collar intermediate its ends, which constitutes a male member in cooperation with an internally splined or keged female member which constitutes part of the rear end structure of the pneumatic percussion hammer. This splined or keged connection enables the compressedair inlet pipe 8 to be longitudinally slidable in relation to thepneumatic percussion hammer 1. As the compressedair inlet pipe 8 is fixed to the drill string, thepneumatic percussion hammer 1 is itself longitudinally adjustable relative to the drill string. The splined or keged connection between the compressedair inlet pipe 8 and thepneumatic percussion hammer 1 also means that rotation of the drill string will cause corresponding rotation of thepneumatic percussion hammer 1. - The front end portion of the compressed
air inlet pipe 8 has acontrol valve 11, which is a portion of increased diameter slidable within the bore of the workingcylinder 6. Depending on the longitudinal position of the compressedair inlet pipe 8, thecontrol valve 11 is capable of covering the ends of thepassages 7 so as to prevent communication between the workingcylinder 6 and thecylindrical chamber 5. - In the position shown in FIG. 1, the
control valve 11 has been pushed to its forwardmost position, i.e. thepneumatic percussion hammer 1 is relatively close to the end of the drill string. In this position, thecontrol valve 11 covers thepassages 7, and thehammer 4 is against the forward internal end of thecylindrical chamber 5. Movement of thehammer 4 is stopped in this position. As the drill string continues its reverse passage through the pilot bore, the connection between the drill string and therear end 10 of the compressedair inlet pipe 8 begins to pull thecontrol valve 11 rearwards, because of the drag on the outer surfaces of the pneumatic percussion hammer against the sides of the bore. The position shown in FIG. 2 is then reached. Thecontrol valve 11 has travelled to the rear of thepassages 7, so that these passages are no longer covered, and compressed air can pass from theworking chamber 6 through thepassages 7 and into thecylindrical chamber 5. The forward part of thehammer 4 has a side channel (not shown) permitting the compressed air to pass to the front part of thecylindrical chamber 5. The compressed air then acts on the front surface of thehammer 4, so as to drive it towards the rear, until the back surface of thehammer 4 impacts on the internal rear end of thecylindrical chamber 5, as shown in FIG. 3. At this point, thepassages 7 have now passed to the rear of thecontrol valve 11, and compressed air now passes in the reverse direction through these passages into the rear part of the workingcylinder 6, and then to the outside of the pneumatic percussion hammer throughexhaust channels 12. - The cycle then repeats itself, with compressed air entering the working
cylinder 6 through the forward end of the compressedair inlet pipe 8. The resulting series of backward hammer blows causes thepneumatic percussion hammer 1 to begin to catch up with the drill string in its reverse passage through the pilot bore. When thepneumatic percussion hammer 1 again approaches the forward end of the drill string, thecontrol valve 11 is again pushed in and the hammer cycle stops. In this way, hammer blows are prevented from being generated when the pneumatic percussion hammer is close to the drill string. - During the phase when the pneumatic percussion hammer is catching up with the reverse passage of the drill string through the pilot bore, the pneumatic percussion hammer is exerting hammer blows in the reverse direction. This enables the pneumatic percussion hammer to perform a backreaming action. A
head 13 in the form of a ring shaped member is fitted on therear end 3 of the pneumatic percussion hammer. Thehead 13 preferably has a flat rear face. This face may have hardenedteeth 14 thereon, as shown in FIG. 4. Thehead 13 is a detachable member, and different size heads 13 may be provided as shown in FIG. 5 for different ground conditions and boring requirements. - FIG. 4 also shows a
screw connection 15 between therear end 10 of the compressed air inlet pipe and the forward end 16 of the drill string. Also shown in FIG. 4 is anouter casing 17 for the pneumatic percussion hammer, which enables it to be used when water is present in the pilot bore, without ingress of water preventing proper operation. Alternatively, the hammer can be constructed with one-way air exhaust passages to prevent the inlet of water. - FIGS.6 to 9 show a variety of designs for the cutting
head 13. Passages may be provided, facing forward and rearward, and optionally at an angle to the axis. These permit air or fluids such as water, bentonite or foam to pass through the head. Larger passages may also be provided in the periphery, as shown at 18, or closer to the centre, as shown at 19, for spoil removal. The head can also be of a star shape as shown in FIG. 8. A reduced or non-interrupted peripheral surface causes powdered spoil to be forced by the air and compression into fissures, voids etc. in the ground, while the uninterrupted surface smooths the bore. - The working face of the
head 13 is preferably flat. This enables the greatest force to be applied to the ground, and in particular to rock and boulders. It ensures that the material is fully cut and powdered before being able to pass back over or through the head passages. This is in contrast to conventional reamers which are generally tapered and tend to jam in the ground or almost stall, and then grind themselves away when confronted with rock and boulders. They also tend to dislodge whole or parts of the rock which are passed through the blades or cutting wheels and lay in the bore, or they dislodge the bore completely causing collapse. The design of the present backreaming tool thus overcomes such problems.
Claims (4)
1. A backreaming tool for expanding a pilot bore produced by a drill string, comprising a pneumatic percussion hammer (1) in combination with a drill string, the drill string being rotatable and reversible through the pilot bore to effect backreaming by the pneumatic percussion hammer;
wherein the pneumatic percussion hammer has a first end (3) adjacent the forward end of the drill string, and a second end (2) remote from the drill string, a compressed air inlet pipe (8) which passes through the first end and into a working cylinder (6) of the hammer, whereby the working cylinder is capable of reciprocating and exerting hammer blows on an internal end surface of the hammer at the first end;
wherein the compressed air inlet pipe (8) is connected to the forward end of the drill string, for supply of compressed air through the drill string into the air inlet pipe, and the compressed air inlet pipe is connected to the pneumatic percussion hammer in longitudinally slidable manner and in rotatably fixed manner, whereby the pneumatic percussion hammer is longitudinally adjustable relative to the drill string but is rotatable in accordance with rotation of the drill string;
and wherein the position of the air inlet pipe (8) relative to the working cylinder (6) is such that the compressed air supply to the working cylinder is cut off when the hammer is longitudinally close to the end of the drill string, then restored as the hammer becomes more distant from the drill string, so as to prevent hammer blows falling on the forward end of the drill string. A shock damping device between the hammer and the drill string may also be employed to further ensure that the hammer blows do not strike the drill string.
2. A backreaming tool according to claim 1 , also comprising shock damping means between the hammer and the drill string.
3. A backreaming tool according to claim 1 or 2, wherein the pneumatic percussion hammer has a flat-faced head at its second end (2).
4. A method of expanding a pilot bore which has been produced by a drill string, which comprises connecting a pneumatic percussion hammer (1) to the forward end of the drill string, supplying compressed air through the drill string to the pneumatic percussion hammer and reversing the drill string through the bore while rotating the drill string, so as to effect backreaming of the pilot bore by the pneumatic percussion hammer;
wherein the supply of compressed air actuates the pneumatic percussion hammer so as to create hammer blows towards the drill string; and
wherein the compressed air supply to the pneumatic percussion hammer is cut off when the hammer is longitudinally close to the end of the drill string, then restored as the hammer becomes more distant from the drill string, so as to prevent hammer blows falling on the forward end of the drill string.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB0010212.9A GB0010212D0 (en) | 2000-04-26 | 2000-04-26 | Backreaming tool |
GB0010212.9 | 2000-04-26 | ||
PCT/GB2001/001879 WO2001081704A1 (en) | 2000-04-26 | 2001-04-26 | Backreaming tool |
Publications (1)
Publication Number | Publication Date |
---|---|
US20040089473A1 true US20040089473A1 (en) | 2004-05-13 |
Family
ID=9890576
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US10/258,755 Abandoned US20040089473A1 (en) | 2000-04-26 | 2001-04-26 | Backreaming tool |
Country Status (7)
Country | Link |
---|---|
US (1) | US20040089473A1 (en) |
EP (1) | EP1276952A1 (en) |
CN (1) | CN1443266A (en) |
AU (1) | AU5053901A (en) |
CA (1) | CA2407042A1 (en) |
GB (1) | GB0010212D0 (en) |
WO (1) | WO2001081704A1 (en) |
Cited By (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007034462A1 (en) * | 2005-09-20 | 2007-03-29 | Minroc Technical Promotions Limited | A percussion hammer for enlarging drilled holes |
US20100276160A1 (en) * | 2008-02-29 | 2010-11-04 | Tolman Randy C | Systems and Methods For Regulating Flow In A Wellbore |
US20150273676A1 (en) * | 2014-03-27 | 2015-10-01 | Michael B. Spektor | Optimized pneumatic hammer |
US10641051B1 (en) * | 2016-09-07 | 2020-05-05 | Dandelion Energy, Inc. | Systems and methods for coupling and decoupling drill heads for ground loop preparation for geothermal applications |
Families Citing this family (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB0114872D0 (en) * | 2001-06-19 | 2001-08-08 | Weatherford Lamb | Tubing expansion |
IES20100502A2 (en) | 2010-08-12 | 2011-04-27 | Minroc Techn Promotions Ltd | An attachment for percussion drill tools |
CN107829685B (en) * | 2017-10-10 | 2023-12-19 | 苏州工业园区科艺通信设备有限公司 | Pneumatic full-section rock reamer of directional drilling machine and reaming process thereof |
CN111577177B (en) * | 2020-04-22 | 2022-03-22 | 中煤科工集团西安研究院有限公司 | Drilling device and drilling method for discharging slag by underground pneumatic impact crushed rock foam |
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US3865200A (en) * | 1971-11-18 | 1975-02-11 | Tracto Technik | Burrowing apparatus |
US4100980A (en) * | 1975-05-31 | 1978-07-18 | Jenne & Strahm Ag Fur Tiefbautechnik | Self-propelled pneumatic burrowing device |
US4117895A (en) * | 1977-03-30 | 1978-10-03 | Smith International, Inc. | Apparatus and method for enlarging underground arcuate bore holes |
US4683960A (en) * | 1984-10-03 | 1987-08-04 | Kostylev Alexandr D | Air-operated reversible percussive action machine |
US4694913A (en) * | 1986-05-16 | 1987-09-22 | Gas Research Institute | Guided earth boring tool |
US5065827A (en) * | 1990-12-21 | 1991-11-19 | Smith International, Inc. | Hammer bit retention tool |
US5190114A (en) * | 1988-11-25 | 1993-03-02 | Intech International Inc. | Flow pulsing apparatus for drill string |
US5238073A (en) * | 1991-04-04 | 1993-08-24 | Rear Ian G | Uphole hammer |
US5791419A (en) * | 1995-09-14 | 1998-08-11 | Rd Trenchless Ltd. Oy | Drilling apparatus for replacing underground pipes |
Family Cites Families (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB9012639D0 (en) | 1990-06-06 | 1990-07-25 | Kayes Allan G | Soil displacement hammer with reversing mechanism |
US5921331A (en) | 1997-04-14 | 1999-07-13 | Straightline Manufacturing, Inc. | Backreamer |
-
2000
- 2000-04-26 GB GBGB0010212.9A patent/GB0010212D0/en not_active Ceased
-
2001
- 2001-04-26 CN CN01811492.XA patent/CN1443266A/en active Pending
- 2001-04-26 US US10/258,755 patent/US20040089473A1/en not_active Abandoned
- 2001-04-26 WO PCT/GB2001/001879 patent/WO2001081704A1/en not_active Application Discontinuation
- 2001-04-26 CA CA002407042A patent/CA2407042A1/en not_active Abandoned
- 2001-04-26 AU AU50539/01A patent/AU5053901A/en not_active Abandoned
- 2001-04-26 EP EP01923856A patent/EP1276952A1/en not_active Withdrawn
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US5238073A (en) * | 1991-04-04 | 1993-08-24 | Rear Ian G | Uphole hammer |
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Cited By (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2007034462A1 (en) * | 2005-09-20 | 2007-03-29 | Minroc Technical Promotions Limited | A percussion hammer for enlarging drilled holes |
US20090071725A1 (en) * | 2005-09-20 | 2009-03-19 | Joseph Purcell | Percussion Hammer for Enlarging Drilled Holes |
US7735584B2 (en) * | 2005-09-20 | 2010-06-15 | Minroc Technical Promotions Limited | Percussion hammer for enlarging drilled holes |
US20100276160A1 (en) * | 2008-02-29 | 2010-11-04 | Tolman Randy C | Systems and Methods For Regulating Flow In A Wellbore |
US8899339B2 (en) | 2008-02-29 | 2014-12-02 | Exxonmobil Upstream Research Company | Systems and methods for regulating flow in a wellbore |
US20150273676A1 (en) * | 2014-03-27 | 2015-10-01 | Michael B. Spektor | Optimized pneumatic hammer |
US10641051B1 (en) * | 2016-09-07 | 2020-05-05 | Dandelion Energy, Inc. | Systems and methods for coupling and decoupling drill heads for ground loop preparation for geothermal applications |
Also Published As
Publication number | Publication date |
---|---|
GB0010212D0 (en) | 2000-06-14 |
AU5053901A (en) | 2001-11-07 |
WO2001081704A1 (en) | 2001-11-01 |
EP1276952A1 (en) | 2003-01-22 |
CN1443266A (en) | 2003-09-17 |
CA2407042A1 (en) | 2001-11-01 |
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Legal Events
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STCB | Information on status: application discontinuation |
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