Drill head for expanding a pilot bore in order to create a borehole

Abstract

A drill head for expanding a pilot bore in order to create a borehole having a borehole wall as a result of loosening rock surrounding the pilot bore in the region of a working face, which extends in a substantially right-angled manner to the pilot bore, including a basic body including a connection element for a pilot bore string including at least two tool holders, in that at least one tool holder is at a greater spacing radially from the basic body than the at least one other tool holder such that there is at least one outer and one inner drilling tool which are movable into engagement with the working face, and the at least one inner drilling tool and the at least one outer drilling tool are each arranged offset at an angle in relation to the working face.

Claims

1. A drill head for expanding a pilot bore in order to create a borehole having a borehole wall as a result of loosening rock surrounding the pilot bore in the region of a working face, which extends in a substantially right-angled manner to the pilot bore for HDD operation, comprising; a basic body, with a connection element for a pilot bore string; at least two tool holders for drilling tools, wherein at least one tool holder is on the basic body, wherein at least one tool holder is at a greater spacing radially from the basic body than the at least one other tool holder and at least one outer and one inner drilling tool are movable into engagement with the working face, and wherein the at least one inner drilling tool and the at least one outer drilling tool are each offset at an angle in relation to the working face; at least a first receiving tool which comprises an additional drilling tool for engaging a region of the working face, wherein the receiving tool is configured to receive the drill cuttings loosened at the working face and removes them from the drilling region and stabilize the drill head from unwanted vertical movement in the horizontal bore; and at least a second receiving tool for receiving drill cuttings which are located on the bottom horizontal wall of the borehole, the receiving tool comprising a receiving surface at an angle of <20 in relation to the alignment line of the borehole.

2. The drill head as claimed in claim 1, wherein the at least two drilling tools are configured to at least one of; create at least one radially circumferential wedge-like recess on the working face, create at least one radially circumferential wedge-like projection on the wearing face, or, have an inside angle between the drilling tools at least one of between 120 and 150, or 135 and 140.

3. The drill head as claimed in claim 1, comprising a flushing nozzle from which a flushing medium can be output, wherein the region between the borehole wall and the outer portion of the drilling tool pointing to the borehole wall is flushable with the output flushing medium.

4. The drill head as claimed in claim 1 comprising at least one flushing nozzle on the receiving tool.

5. The drill head as claimed in claim 1 comprising a crushing tool for crushing the drill cuttings, the crushing tool comprising a crushing surface which is movable along the borehole wall to create a crushing gap between the crushing surface and the borehole wall.

6. The drill head as claimed in claim 5 wherein at least one of the crushing gap is adjustable, the crushing surface is disposed at an angle in relation to the borehole wall, or the crushing tool is disposed on an outside surface of a receiving tool.

7. The drill head as claimed in claim 1 wherein the first receiving tool comprises on a radial outside surface at least one of a centering surface or a crushing surface.

8. The drill head as claimed in claim 1 wherein at least one tool holder is radially adjustable.

9. The drill head as claimed in claim 8 comprising spacers for the radial adjustability.

10. The drill head as claimed in claim 1 comprising at least one centering element on the side of the drill head remote from the working face.

11. The drill head as claimed in claim 1 wherein the connection element is at least one of, elongated with respect to the entry into the pilot bore, substantially the same diameter as the pilot bore stand, or comprises a centering portion with a diameter which is substantially identical to the diameter of the pilot bore.

12. The drill head as claimed in claim 1 comprising at least one stabilizing element which comprises on the stabilizing element's outside surface a contact portion, at least one of flat or with the radius of the borehole wall.

13. The drill head as claimed in claim 1 wherein at least one of the first receiving tool or the drilling tool comprises the form of the surface contour of the working face.

14. The drill head as claimed in claim 1 wherein the first receiving tool covers the drilling region of the drill head in a radial manner.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

(1) The solutions to the inventions are described in more detail below by way of a preferred exemplary embodiment in conjunction with a further drawing, in which:

(2) FIG. 1 shows a first three-dimensional view of a drill head according to the invention in a borehole,

(3) FIG. 2 shows a second three-dimensional view of FIG. 1,

(4) FIG. 3 shows a further three-dimensional view of the drill head according to the invention,

(5) FIG. 4 shows a part-sectioned three-dimensional side view of the drill head according to the invention and a part-sectioned three-dimensional side view of the borehole produced by the drill head according to the invention,

(6) FIG. 5 shows a view of a cutout of FIG. 4 without a surrounding borehole,

(7) FIG. 6 shows a sectioned partial view of the drill head according to the invention,

(8) FIG. 7 shows a further partial view of the drill head according to the invention,

(9) FIG. 8 shows a tool holder with a drilling tool of the drill head according to the invention in a first position,

(10) FIG. 9 shows a second position of FIG. 8,

(11) FIG. 10 shows a part-sectioned view of a stabilizer according to the invention and

(12) FIG. 11 shows a sectioned view of FIG. 10.

DETAILED DESCRIPTION

(13) FIG. 1 and FIG. 2 show a borehole 100 in a soil/rock mass 101, into which, once the borehole 100 has been finished, a pipeline (not shown) is inserted. Upstream of the borehole 100 is a pilot bore 102 which has already been produced from a launch point (not shown) to a target point (not shown). As can be seen in FIG. 1, the borehole 100 comprises a working face 103 and a borehole wall 104. The working face 103 extends in a substantially right-angled manner to the pilot bore 102.

(14) A drill head 10, an expansion drill head, is arranged in the borehole 100. The drill head 10 comprises a basic body 11 on which are arranged cross struts 12 which are connected at radial spacings to a support ring 13. The cross struts 11 are provided with tool holders 14 on which cutting rollers 15 are arranged. The cutting rollers 15 comprise teeth 16 produced from a hard metal, such as tungsten carbide, for loosening the soil, or rock 101, at the working face 103.

(15) In addition, a first connection 17 for the drill pipes (not shown) located in the pilot borehole 102 and a second connection 18 on the rear end of the drill head 10 for the connection of the drill string (not shown) located in the borehole 100 are arranged on the basic body 11. A stabilizer 19, which comprises substantially the same diameter as the pilot borehole 102 and is situated therein, is provided on the first connection 17.

(16) As can be seen from the right-hand image in FIG. 4, the working face 103 comprises a V-shaped cut 105 which is provided extending radially around the pilot borehole 102. It has been proved that as a result of providing the V-shaped cut 105, the drill head 10 is particularly stabilized in relation to the borehole 100. To create the V-shaped cut 105, a certain number of tool holders 14 are aligned such that the cutting roller 15 thereof engages with the outer leg 106 of the V-shaped cut 105, which is at a further spacing radially from the pilot borehole 102, and produces the same, whilst a further number of tool holders 14 are arranged such that the cutting roller 15 thereof engages with the inner leg 107 of the V-shaped cut 105, which is at a lesser spacing radially from the pilot borehole, and produces the same. As an alternative to this and not shown here, it is also possible for the V-shaped cut 105 to be realized inversely, that is to say as a projection, projecting into the borehole 100. It is then necessary to arrange the tool holders 14 and the cutting rollers 15 arranged therein in a corresponding manner for this purpose. In the present embodiment of the drill head 10, three cutting rollers 15 are arranged such that the outer leg 106 of the working face 103 is created, whilst two cutting rollers 15 are provided for producing the inner leg 107.

(17) Flushing nozzles 20 are provided on the tool holders, the cutting rollers 15 of which create the outside leg 106, said flushing nozzles are arranged such that they flush the gap 108 between the outer row of teeth 21 of the cutting roller 15 and the borehole wall 104 in order to avoid wear on the outer row of teeth 21 in a targeted manner. On account of the small gap width of the gap 108, drill cuttings 109 accumulate here, in particular on the bottom 113 of the borehole, and correspondingly lead to excessive wear on the outer row of teeth. This is avoided as a result of flushing the gap 108 in a targeted manner.

(18) In addition, a reamer tool/receiving tool 22 is provided on a cross strut 12. The reamer tool 22 serves as receiving tool for receiving drill cuttings 109 at the working face 103. It comprises a drilling tool 23 on its front side. The drilling tool 23 comprises substantially the same form as the V-shaped cut 105 and is applied to said cut when the drill head 10 rotates. The reamer tool 22 removes the drill cuttings 109, loosened by the cutting rollers 15, out of the cutting range of the cutting rollers 15. In addition, the drilling tool 23 of the reamer tool 22 engages the working face 103 and is able to loosen and to remove loose rock located at the working face 103, or rock loosened by the cutting roller 15. Loose rock moving through the cutting rollers 15 is avoided as a result, which brings about a reduction in wear. A flushing nozzle 20 for flushing the gap 108 is also provided on the reamer tool 22. In addition, flushing nozzles 24, which flush the working face 103, or the V-shaped cut 105, are provided on the reamer tool 22. With reference to the diameter of the borehole 100, the reamer tool 22 is arranged offset at an angle in relation to said borehole. An enlarged representation of the reamer tool 22 is shown in FIG. 5. In addition, stabilizer surfaces 29, which are provided with a changeable wear plate 30, are provided on the outside surface of the cross struts 12. The stabilizer surfaces 29, as also the stabilizer 19, bring about better centering of the drill head 10 in the borehole 100, in which the stabilizer surfaces, or the wear plates 30 thereof, engage with the borehole wall 104. In addition, reamer tools 25 which comprise an elongated basic body 26 (see FIG. 7), are provided on the support ring 13. A wear plate 27 is arranged on their side facing the borehole wall 104. A wear plate 28 is arranged on the side surface of the basic body 26. The wear plates 27, 28 are realized so as to be changeable. By means of the wear plates 27, 28, the reamer tools 25 entrain drill cuttings 109, which are arranged in particular on the bottom 113 of the borehole, and convey them upward, as shown in FIG. 11, along the borehole wall 104 in the borehole 100 until the drill cuttings 109 are loosened from the entrainment region 31 in front of the wear surface 28 on account of gravity and drop down. As a result, the drill cuttings 109 pass into a flow region 110 in which a higher speed of the drill fluid predominates than in the outside regions of the borehole wall 104, as a result of which the drill cuttings 109 are entrained in the flow again, as is shown in FIG. 10.

(19) The arrangement of the reamer tools 25 with reference to the drill head 10 is provided in this case such that the receiving surface, provided on the basic body 26 and covered with a wear plate 28, is at an angle of between 0 and 20 in relation to the alignment line of the borehole 100, as it has been shown that the drill cuttings are transported particularly well in the entrainment region 31 toward the borehole highest point 111 as a result.

(20) As is shown in FIG. 6, a crushing tool 32 is provided on the reamer tool 22. This is a crushing surface 33 which is provided with a wear plate 34 which is realized so as to be changeable. The crushing surface is arranged at an angle in relation to the borehole wall 104, as shown in FIG. 6. A crushing gap 112, in which a cuttings lump 109 which is larger than the crushing gap 112 collects and is crushed by the shear forces forming in the crushing gap 112 between the borehole wall 104 and the crushing surface 33, is formed between the crushing surface 33 and the borehole wall 104. The crushing tool 32 can also be provided on the reamer tools 25 for crushing the drill cuttings 109 in a better manner. The crushing tool 32 can be arranged in different positions on the reamer tool 22, 25 such that the adjustability of the crushing gap 112 is achievable in dependence on the desired maximum size of the drill cuttings 109.

(21) A retaining ring 35 which is connected to the support ring 13 by means of diagonal struts 36, is arranged on the rear surface of the support ring 13. Better stability of the support ring 13 with reference to the basic body 11 is achieved as a result. Flushing nozzles 37 are provided on the rear surface of the cross struts 12 and, as a result of the additional discharging of flushing medium, these bring about a higher flow speed of the flushing medium precisely into the outside regions of the borehole 100 toward the borehole wall 104 such that better discharge of the drill cuttings 109 is ensured.

(22) As it has been shown that it is possible for the diameter of the borehole 100 to alter as a result of wear on the cutting rollers 15, which, once the cutting rollers 15 have been changed, causes additional overrunning of the regions with a reduced diameter by the new cutting rollers 15 when the drill head 10 is re-installed into the borehole 100 and consequently renewed wear on the outside surfaces of the cutting rollers 15, the cutting rollers 15 are displaceably arranged in the tool holder 14 so as to be radially displaceable between a first position (as shown in FIG. 8) and a second position (as shown in FIG. 9). A spacer 38, by way of which the cutting roller 15 is fixed in its respective position on the outside or inside surface of the tool holder 14, is provided in the tool holder 14 in order to fix the cutting roller 15.

(23) In order to achieve even better centering of the drill head 10 and, over and above this, a reduction in the wear on the cutting rollers 15 when the drill head 10 is inserted and removed, or better removal of the drill cuttings 109, centering elements 40 are provided in the drill string 39 which is arranged on the connection 18 behind the drill head 10. Said centering elements comprise a basic body 41 on which cross struts 42 are arranged in the radial direction toward the borehole wall 104. Stabilizing portions 43, which cover part of the borehole wall 104, are arranged on the cross struts 42. As shown in FIG. 10, several cross struts 42 can also be provided behind one another. On one side, the stabilizing portions 48 comprise a reamer tool 44, in front of which an entrainment region 31 is formed. The reamer tool essentially comprises one receiving surface 45 which is provided with a wear plate 28. By means of the reamer tool 44, the drill cuttings 109, as shown in FIGS. 10 and 11, are entrained, conveyed to the borehole highest point 111, from where the drill cuttings 109 then fall into the flow region 110 of the drill fluid and thus are supplied again to the discharge of the drill cuttings 109 out of the borehole 100. Part of the drill cuttings 109, as shown in FIG. 10, is deposited on the bottom 113 of the borehole again. When the drill head 10 is removed, this is then also received once again and supplied to the flow region 110 again in a corresponding manner. Should it be necessary to rotate the drill head 10 and consequently also the centering element 40 in different directions, a corresponding reamer tool can be provided on both sides on the stabilizing portion 43, as shown in FIG. 11.

LIST OF REFERENCES

(24) 10 Drill head 11 Basic body 12 Cross strut 13 Support ring 14 Tool holder 15 Cutting roller 16 Tooth 17 Connection 18 Connection 19 Stabilizer 20 Flushing nozzle 21 Outer row of teeth 22 Reamer tool/receiving tool 23 Drilling tool 24 Flushing nozzle 25 Reamer tool/receiving tool 26 Basic body 27 Wear plate 28 Wear plate 29 Stabilizer surface 30 Wear plate 31 Entrainment region 32 Crushing tool 33 Crushing surface 34 Wear plate 35 Retaining ring 36 Diagonal strut 37 Flushing nozzle 38 Spacer 39 Drill string 40 Centering element 41 Basic body 42 Cross strut 43 Stabilizer portion 44 Reamer tool 45 Receiving surface 100 Borehole 101 Soil/rock 102 Pilot bore 103 Working face 104 Borehole wall 105 V-shaped cut 106 Outside leg 107 Inside leg 108 Gap 109 Drill cuttings 110 Flow region 111 Borehole highest print 112 Crushing gap 113 Borehole bottom Incidence angle