EP3039218A2

EP3039218A2 - Drill head for expanding a pilot bore in order to create a borehole

Info

Publication number: EP3039218A2
Application number: EP14750442.7A
Authority: EP
Inventors: Michael LUBBERGER; Tobias GERHARDT
Original assignee: Herrenknecht AG
Current assignee: Herrenknecht AG
Priority date: 2013-08-15
Filing date: 2014-08-08
Publication date: 2016-07-06
Anticipated expiration: 2034-08-08
Also published as: CA2921478A1; US10364611B2; CA2921478C; RU2016109021A; EP3039218B1; WO2015022065A3; AU2014308209B2; WO2015022065A2; US20160305189A1; RU2652197C2; DE102013013477A1

Abstract

The invention relates to a drill head for expanding a pilot bore in order to create a borehole having a borehole wall by removing rock surrounding the pilot bore in the region of a working face extending substantially at a right angle to the pilot bore, said drill head comprising a main body, on which a connecting element for a pilot drill string is provided, at least one tool retainer for at least one drilling tool being provided on the main body, characterised in that at least two tool retainers are provided, in that at least one tool retainer is radially spaced from the main body further than the at least one other tool retainer, such that at least one outer and one inner drilling tool are present, which can be brought into engagement with the working face, and in that the at least one inner drilling tool and the at least one outer drilling tool are each arranged in an offset manner at an angle to the working face.

Description

Drilling head for expanding a pilot hole to create a borehole Description

The invention relates to a drill head for expanding a pilot hole for creating a borehole with a borehole wall by loosening a rock surrounding the pilot hole in the region of a substantially perpendicular to the pilot bore extending working face with a base body on which a connecting element for a pilot drill string is provided, wherein the base body at least one tool holder are provided for at least one drilling tool.

From EP 0 360 321 a so-called HDD method (Horizontal Directional Drilling) is known in which a pilot hole is created from a starting point to a destination point for the trenchless laying of a pipeline under an obstacle along a predetermined drilling line. Subsequently, a reamer is attached to the pilot drill string at the target side, which is connected to the pipeline to be laid. Turning the pilot string drives the reamer. An advancement of the scraper while pulling in the pipeline takes place by pulling out the pilot drill string. The reamer is designed so that it is closed at the connection side to the pipeline. Only a discharge line for the removal of the dissolved soil in conjunction with a suspension for lubrication of the pipeline, to keep open the borehole and for transporting the cuttings is provided in the drilling line. On the front of the scraper is designed to be open, so that the soil dissolved by the scraper can enter the reamer and mixed there mixed with water can be removed. The reamer itself represents a cylindrical body with teeth on its front which loosens the floor. US 5,269,384 discloses a method and apparatus for expanding a borehole. Here, as well as by means of an HDD bore a pilot hole is produced. Subsequently, a reamer at the

CONFIRMATION COPY Pilot drill string installed. Behind the reamer, a pipeline is provided, which substantially corresponds to the diameter of the pilot drill string.

In practice, it has been found that when using the HDD method, the expansion drill heads are subject to considerable wear. This is particularly the case when a so-called single-pass method is used, in which the expansion of the pilot hole is made to the final diameter of the borehole to be produced. The wear takes place essentially on the roller chisels / cutting rollers. If these are worn before reaching the end point, the expansion head must be removed from the hole and the bits replaced and then the expansion head returned to the hole to continue the drilling. This leads to considerable set-up times. It turns out that different aspects are responsible for the closure.

First, the centering of the drill head in the borehole or in the pilot hole to call. Bad centering has a negative effect on the life of the cutter (cutting rollers) and their bearings and carbide inserts. Furthermore, an insufficient centering causes the entry of vibrations and vibrations that continue through the drill pipe to the connected drill. Bad centering in the borehole continues to lead to non-round boreholes along the route to be drilled. This affects the wear of the next pass on several of the widening passes.

Furthermore, wear occurs because large cuttings settle directly behind the drill head on the bottom of the hole and is not flushed by means of the introduced suspension to the outlet opening of the bore. These remain there in the sole in a kind of bed and are run over only once by an extension and retraction of the Aufweitbohrkopfes from the bore / into the hole and further crushed. So far this problem is either ignored or it causes the borehole diameter to become oversized to make room for the collection of the product pipeline which is introduced into the borehole. The wear generally causes the intervals for replacement of the rollers to become smaller. In addition, it first leads to the loss of the carbide tipped carbide inserts of the cutting roll, which in turn results in a smaller bore hole.

The object of the invention is therefore to provide a drill head, in which the wear on the cutting rollers is reduced. According to the invention, a first solution provides for the object that at least two tool holders are provided, that at least one tool-holder is radially spaced from the main body further than the at least one other tool holder, so that at least one outer and one inner drilling tool are present, with the working face in Engagement can be brought, and that the at least one inner drilling tool and the at least one outer drilling tool are each arranged offset at an angle to the working face.

It has surprisingly been found that the drill head is optimally centered relative to the working face by the angular arrangement of the drilling tools to each other, so that a significant reduction of wear takes place.

A preferred teaching of the invention provides that the two drilling tools are arranged so that the working face has at least one radially circumferential wedge-like recess or at least one radially encircling wedge-like projection. It is advantageous that the internal angle between the drilling tools 120 to 150 ° is preferably 135 to 140 °. According to the invention, a second solution provides the object that a rinsing nozzle is provided, from which a rinsing medium can be dispensed, wherein the rinsing nozzle is arranged such that the area between the borehole wall and the borehole wall facing outer portion of the drilling tool is flushable with the dispensed rinsing medium. Surprisingly, it has been found that by selective rinsing of the gap in the caliber area between the borehole wall and the cutting rollers in a simple manner, the wear can be significantly reduced.

According to the invention, a third solution provides the object that at least one receiving tool is provided, which has an engagement region with the working face, on which a drilling tool is arranged, and in that the receiving tool picks up the drill cuttings loosened at the working face and removes them from the drilling area.

Again, it has surprisingly been found that the wear is significantly reduced by the direct inclusion of the cuttings at the working face. Furthermore, there is a reduction in the wear on the cutting rollers, because the provision of a separate drilling tool on the receiving tool which is possibly located at the working face partially dissolved rock or loosens with existing loose rock by the additional drilling tool and not released from the cutting rollers and further crushed must be, which also leads to wear of the cutting rollers.

A preferred teaching of the invention provides that at least one rinsing nozzle is provided on the receiving tool. This improves the removal of the cuttings and supports the loosening of partially dissolved rock or with existing loose rock.

Furthermore, it is advantageous that the receiving tool and / or the drilling tool has the shape of the surface contour of the working face. Another teaching of the invention provides that the receiving tool radially covers the drilling area of the drill head. As a result, a particularly thorough removal is guaranteed.

According to the invention, a fourth solution provides for the task of providing a comminution tool for comminuting the cuttings, which has a comminution surface which is movable along the borehole wall, so that a comminution gap is provided between comminution surface and borehole wall.

The provision of such a crushing tool directly on the drill head causes a better discharge of the cuttings takes place. Large diameter loosened cuttings may be less chargeable due to the flow of flushing medium flowing down the well and tend to settle on the bottom of the well. A crushing tool has been used only when discharged through a dedicated pipe, for example, in microtunnelling or similar methods. In HDD processes, such additional breakage was previously not possible.

A preferred teaching of the invention provides that the comminution gap is adjustable. This makes it possible to take into account the maximum grain size of the discharge as a function of the flushing medium.

Furthermore, it is advantageous that the crushing surface is arranged incident to the borehole wall. As a result, a particularly good crushing result is achieved.

Another teaching of the invention provides that the crushing tool is arranged on an outer side of a receiving tool. This represents an efficient arrangement possibility of the tool without additional elements on the drill head.

According to the invention, a fifth solution provides for the object that at least one receiving tool is provided for receiving drill cuttings lying on the bottom of the borehole, which has a receiving surface which is incident with respect to the alignment line of the borehole at an angle of <20 °.

Surprisingly, it has been shown that in this way a particularly effective removal of the cuttings is possible. Due to the shallow angle, the cuttings are not scooped behind the drill bit, but it is taken along the circumference of the borehole and falls due to the borehole highest down through gravity and from there directly into the stream of flushing medium.

A preferred teaching of the invention provides that the receiving surface is provided on its radially outer side with a centering surface and / or a crushing surface.

According to the invention, a sixth solution provides the object that the tool holder is arranged so that it is radially adjustable.

Surprisingly, it has been found that in this way the wear of the outer cutting rollers can be significantly reduced. The adjustment causes a new boring tool to not overly work after replacement on the way to the working face during reassembly, especially in the caliber area, since the diameter does not have to be widened in the area machined by the worn cutting rollers to be the diameter for retracting To allow drilling head with the new cutting rollers. A preferred teaching of the invention provides that spacers are provided for providing the adjustability. This is a particularly easy way to adjust.

These six aforementioned solutions of the object according to the invention can be combined in an advantageous manner to reduce wear.

A further teaching of the invention provides that on the side facing away from the working face of the drill head at least one effective against the borehole wall centering element is present. As a result, a further improvement in the stabilization of the drill head can be achieved in a simple manner.

A further teaching of the invention provides that the connecting element is designed to be elongated for entry into the pilot bore and / or is designed essentially with a diameter of the pilot drilling stand and / or one Centering portion having a diameter substantially equal to the diameter of the pilot bore diameter. As a result, a further improvement in the stabilization of the drill head can be achieved in a simple manner.

A further teaching of the invention provides that at least one stabilizing element is provided, that on its outer side has a contact portion, plan or radius of the borehole wall, and that the stabilizing element is preferably designed as a receiving tool. As a result, a further improvement in the stabilization of the drill head can be achieved in a simple manner.

A further teaching of the invention provides that a centering element described below is provided behind the drill head.

According to the invention, a further solution provides for the object that behind a drill head, in particular a drill head of the previously described embodiment, a Zetrierelement is arranged with a base body having connecting elements for mounting the centering in a drill string, wherein on the base body like a segment of at least one support element arranged on the base body are provided executed portions, which coincide with the Bohrradius of the drill head, wherein at least a portion of a receiving tool for receiving lying on the bottom of the drill hole cuttings having a receiving surface, with respect to the alignment line of the borehole with an angle < 20 ° occurs.

By providing the centering of the drill string is stabilized behind the drill head, which has a direct positive effect on the centering of the drill head relative to the working face. Furthermore, the targeted discharge of the possibly downed on the bottom hole Bohrklechsohle re-crossing the drill head and the associated wear is avoided. A further teaching of the invention provides that the receiving surface on its radial outer side is preferably provided with a centering surface and / or a comminuting surface. In addition, it should be added that the expression "and / or" is understood to mean both "and" and "as well as" or "linking of the corresponding features.

The solutions of the invention with reference to a preferred embodiment in conjunction with another drawing will be described in more detail.

Show

Fig. 1 is a first spatial view of an inventive

Drilling head in a borehole

2 is a second perspective view of FIG. 1,

Fig. 3 is another spatial view of the invention

drill head,

4 is a partially cutaway side view of the drill head according to the invention and a partially cutaway side view of the hole produced by the drill head according to the invention,

5 is a sectional view of FIG. 4, without surrounding borehole,

6 is a partial sectional view of the drill head according to the invention, Fig. 7 is a further partial view of the drill head according to the invention,

Fig. 8 is a tool holder with drilling tool of the invention

Drill head in first position, 9 is a second position to Fig. 8,

10 shows a stabilizer according to the invention in a partially sectioned view, and

11 is a sectional view of FIG. 10th

FIG. 1 and FIG. 2 show a borehole 100 in a soil / rock 101 into which a pipeline (not shown) is introduced after completion of the borehole 100. Upstream of the borehole 100 is a pilot bore 102 already made from a starting point (not shown) to a target point (not shown). As can be seen in FIG. 1, the borehole 100 has a working face 103 and a borehole wall 104. The working face 103 extends essentially at right angles to the pilot bore 102.

In the wellbore 100 a drill head 10 is arranged, which is an expansion drill head. The drill head 10 has a base body 11, on which transverse struts 12 are arranged, which are radially spaced connected 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 have teeth 16 made of a hard metal, such as tungsten carbide, for dissolving the soil, or rock 101, at the working face 03. Furthermore, a first connection 17 for the drill pipe (not shown) located in the pilot borehole 102 and a second connection 18 at the rear end of the drill head 10 for connecting the drill string (not shown) located in the borehole 100 are arranged on the main body 11. At the first port 17, a stabilizer 19 is provided, which has substantially the same diameter as the pilot well 102 and is located in this.

As can be seen from the right-hand illustration of FIG. 4, the working face 103 has a V-shaped break-in 105 which extends radially around the pilot bore hole 102 is provided circumferentially. It has been found that by providing the V-shaped burglary 105, the drill head 10 is particularly stabilized with respect to the wellbore 100. To create the V-shaped break-in 105, a number of tool holders 14 are aligned so that their cutting roller 15 engages and engages the outer leg 106 of the V-shaped break-in 105, which is further radially spaced from the pilot bore 102 another number of tool holders 14 are arranged so that their cutting roller 15 is in engagement with and produces the inner leg 107 of the V-shaped burglary 105 which is less radially spaced from the pilot borehole. Alternatively and not shown here, it is also possible that the V-shaped burglary 105 inversely, so as a projection, is carried out einragend in the wellbore 100. For this it is then necessary to arrange the tool holder 14 and the cutting rollers 15 arranged therein accordingly. In the present embodiment of the drill head 10, three cutting rollers 15 are arranged so that the outer leg 106 of the working face 103 is created, while two cutting rollers 15 are provided for producing the inner leg 107.

At the tool holders whose cutting rollers 15 create the outer leg 106, flushing nozzles 20 are provided, which are arranged so that they rinse the gap 108 between the outer row of teeth 21 of the cutting roller 15 and the borehole wall 104 in order to specifically the wear of the outer row of teeth 21st to avoid. Due to the small gap width of the gap 108, cuttings 109 collect here, in particular on the borehole bottom 113, which accordingly leads to excessive wear of the outer row of teeth. By selectively flushing the gap 108 this is avoided.

Furthermore, a broaching tool / receiving tool 22 is provided on a transverse strut 12. The broaching tool 22 serves as a receiving tool for receiving cuttings 109 at the working face 103. It has a drilling tool 23 on its front side. The drilling tool 23 has substantially the same shape as the V-shaped burglary 105 and sweeps it when rotating the drill head 10. The broaching tool 22 removes the cuttings 109 released by the cutting rollers 15 from the Further, the drilling tool 23 of the broaching tool 22 is in engagement with the working face 103 and is capable of loosening rock at the working face 103, or rock dissolved by the cutting rollers 15. As a result, the passage of loose rock is avoided by the cutting rollers 15, which causes a reduction in wear. On reaming tool 22, a rinsing nozzle 20 is also provided for rinsing the gap 108. Furthermore, 22 rinsing nozzles 24 are provided on the broach, which flush the working face 103, or the V-shaped burglary 105. The broach 22 is offset with respect to the diameter of the wellbore 100 at an angle therefrom. The broach 22 is shown in an enlarged view in Fig. 5. Furthermore, 12 stabilizer surfaces 29 are provided on the outside of the transverse struts, which are provided with a removable wear plate 30. The stabilizer surfaces 29 cause, as well as the stabilizer 19, a better centering of the drill head 10 in the wellbore 100, in which the stabilizer surfaces, or their wear plates 30, are in engagement with the borehole wall 104. Furthermore, reaming tools 25 are provided on the carrier ring 13, which have an elongate base body 26 (see FIG. 7). At its the borehole wall 104 side facing a wear plate 27 is arranged. On the side surface of the base body 26, a wear plate 28 is arranged. The wear plates 27, 28 are made replaceable. The broaching tools 25 carry over the wear plates 27, 28 cuttings 109, which in particular arrange on the bottom 113 of the borehole, carry them, as shown in Fig. 11, along the borehole wall 104 along in the borehole 100 upwards until the Cuttings 109 due to gravity is released from the driving area 31 in front of the wear surface 28 and falls down. As a result, the drill cuttings 109 enter a flow region 10, in which there is a higher rate of boron purging than on the outer regions of the borehole wall 104, as a result of which the drill cuttings 109 are taken back into the flow, as shown in FIG.

The arrangement of the broaches 25 with respect to the drill head 10 is provided so that provided on the base body 26 and with a Wear plate 28 covered receiving surface with respect to the alignment line of the borehole 100 at an angle of 0 ° to 20 ° is incident, since it has been shown that this is a particularly good cuttings transport in the driving area 31 to the borehole highest 111 takes place.

As shown in FIG. 6, a comminution tool 32 is provided on the broach 22. This is a crushing surface 33, which is provided with a wear plate 34, which is designed to be interchangeable. The crushing surface is arranged incident to the borehole wall 104 at an angle a, as shown in FIG. Between the crushing surface 33 and the borehole wall 104, a crushing gap 112 is formed, in which a cuttings chunk 109, which is larger than the crushing gap 112, collects and is comminuted by the shear forces forming in the comminution gap 112 between the borehole wall 104 and the comminuting surface 33. The comminution tool 32 may also be provided on the broaching tools 25 for better comminution of the cuttings 109. The comminuting tool 32 can be arranged on the broaching tool 22, 25 at different positions, so that an adjustability of the comminution gap 112 in dependence on the desired maximum size of the cuttings 109 can be achieved.

At the back of the support ring 13, a retaining ring 35 is arranged, which is connected via diagonal struts 36 with the support ring 13. As a result, a better stability of the carrier ring 13 with respect to the base body 11 is achieved. Rinsing nozzles 37 are provided on the rear side of the transverse struts 12, which cause a higher flow rate of the flushing medium through the additional delivery of the flushing medium, especially in the outer regions of the borehole 100 towards the borehole wall 104, so that a better discharge of the cuttings 109 is ensured.

Since it has been shown that the diameter of the borehole 100 can change as a result of wear on the cutting rollers 15, after the exchange of the cutting rollers 15 an additional crossing of the areas of reduced diameter by the new cutting rollers 15 during the replacement of the Drill head 10 into the borehole 100 and thus causes a renewed wear of the outer sides of the cutting rollers 15, the cutting rollers 15 in the tool holder 14 are displaceable between a first position (as shown in Fig. 8) and a second position (as shown in Fig. 9) arranged radially displaceable. In order to effect a fixation of the cutting roller 15 in the tool holder 14, a spacer 38 is provided, with which the cutting roller 15 is fixed at its respective position on the outer or inner side of the tool holder 14. In order to achieve an even better centering of the drill head 10 and beyond a reduction of the wear of the cutting rollers 15 during installation and removal of the drill head 10, or an improved removal of the drill cuttings 109, are in the connection 18 behind the drill head 10 arranged drill string 39 Centering elements 40 are provided. These have a main body 41, are arranged on the transverse struts 42 in the radial direction to the borehole wall 104 out. Stabilizing portions 43, which cover part of the borehole wall 104, are arranged on the transverse struts 42. As shown in Fig. 10, a plurality of transverse struts 42 may be provided one behind the other. The stabilizing sections 48 have a broach 44 on one side, in front of which a driving area 31 is formed. The broaching tool essentially has a receiving surface 45, which is provided with a wear plate 28. About the reamer 44, the cuttings 109, as shown in FIGS. 10 and 11, taken along, transported to the highest hole 111, from where then the cuttings 109 falls into the flow area 1 10 of the drilling fluid and so the discharge of cuttings 109 from the well 100th is fed again. A portion of the cuttings 109 will settle on the bottom of the borehole 113 as shown in FIG. When removing the drill head 10, this is then also taken up again and fed to the flow area 110 accordingly. Should it be necessary to rotate the drill head 10 and thus also the centering element 40 in different directions, a corresponding broaching tool can be provided on the stabilizing section 43 on both sides, as shown in FIG. 11. LIST OF REFERENCE NUMBERS

10 boring head 37 rinsing nozzle

11 main body 38 spacer

12 cross strut 39 drill string

13 carrier ring 40 centering

14 Tool holder 41 basic body

15 cutting roller 42 cross strut

16 tooth 43 stabilizer section

17 Connection 44 Broaching tool

18 Connection 45 Recording surface

19 stabilizer 100 borehole

20 rinse nozzle 101 soil / rock

21 outer row of teeth 102 Pilot drill hole

22 broach / 103 working face

Pick-up tool 104 borehole wall

23 Drill 105 V-shaped burglary

24 Rinse nozzle 106 Leg, outside

25 broach / 107 thighs, inside

Pick-up tool 108 gap

26 Body 109 Cuttings

27 wear plate 110 flow area

28 Wear plate 111 Highest hole

29 stabilizer surface 112 crushing gap

30 wear plate 113 borehole bottom

31 Driving range α angle of incidence

32 shredding tool

33 crushing surface

34 wear plate

35 retaining ring

36 diagonal strut

Claims

Drilling head for expanding a pilot hole for creating a well patent claims

A wellhead for expanding a pilot bore for creating a wellbore having a well wall by loosening a rock surrounding the pilot well in the region of a face perpendicular to the pilot bore having a body to which a pilot drill string connector is provided, on the body at least one tool holder is provided for at least one drilling tool, characterized in that at least two tool holders are provided, that at least one tool puller is radially spaced from the body further than the at least one other tool holder, so that at least one outer and one inner drilling tool are present can be brought into engagement with the working face, and that the at least one inner drilling tool and the at least one outer drilling tool are each offset at an angle to the working face.

2. Drilling head according to claim 1, characterized in that the two drilling tools are arranged so that the working face has at least one radially circumferential wedge-like recess or at least one radially circumferential wedge-like projection.

3. Drilling head according to claim 1 or 2, characterized in that the internal angle between the drilling tools 120 to 150 ° is preferably 135 to 140 °.

4. Drilling head according to one of claims 1 to 3, characterized in that a rinsing nozzle is provided, from which a flushing medium can be discharged, wherein the rinsing nozzle is arranged so that the area between the borehole wall and the outer section of the drilling tool facing the borehole wall can be flushed with the dispensed rinsing medium,

5. Boring head according to one of claims 1 to 4, characterized in that at least one receiving tool is provided, the one

Engagement region with the working face, on which a drilling tool is arranged, and that the receiving tool receives the dissolved at the working face cuttings and carries away from the drilling area, wherein the receiving tool preferably at least one rinsing nozzle is provided, and preferably the receiving tool and / or Drill tool has the shape of the surface contour of the working face, and / or wherein the receiving tool preferably radially covers the drilling area of the drill head,

6. Drilling head according to one of claims 1 to 5, characterized in that a crushing tool is provided for crushing the cuttings having a crushing surface which is movable along the borehole wall, so that between crushing surface and borehole wall a crushing gap is provided, wherein preferably Crushing gap is adjustable and / or the crushing surface is arranged incident to the borehole wall, and / or the crushing tool is arranged on an outer side of a receiving tool,

7. Drilling head according to one of claims 1 to 6, characterized in that at least one receiving tool for receiving lying on the bottom of the well cuttings is provided, which has a receiving surface which is opposite to the alignment line of the borehole with an angle <20 °, wherein the receiving surface is preferably provided on its radial outer side with a centering surface and / or a comminution surface,

8. Drilling head according to one of claims 1 to 7, characterized in that the tool holder is arranged so that it is radially adjustable, wherein preferably provided for providing the adjustability spacers.

9. A drill head for expanding a pilot hole for creating a borehole with a borehole wall by loosening a surrounding the pilot hole rock in the region of a substantially perpendicular to Pilothole extending working face with a base body to which a connecting element for a pilot drill string is provided, wherein at least one tool holder for at least one drilling tool are provided on the base body, characterized in that a rinsing nozzle is provided, from which a flushing medium can be discharged, wherein the rinsing nozzle is arranged so that the area between the borehole wall and the borehole wall facing outer portion of the drilling tool is flushable with the dispensed rinsing medium.

10. Drilling head according to claim 9, characterized in that at least two tool holders are provided, that at least one tool holder is radially spaced from the main body further than the at least one other tool holder, so that at least one outer and one inner drilling tool are present, with the working face can be brought into engagement, and that the at least one inner drilling tool and the at least one outer drilling tool are each offset at an angle to the working face, the two drilling tools are preferably arranged so that the working face at least one radially circumferential wedge-like recess or at least one Having radially circumferential wedge-like projection and / or, wherein the inner angle between the drilling tools 120 to 150 ° preferably 135 to 140 °, and / or that at least one receiving tool is provided which has an engagement region with the working face on which a drilling tool arranged i st, and that the receiving tool receives the drill cuttings loosened at the working face and removes them from the drilling area, wherein preferably at least one rinsing nozzle is provided on the receiving tool, and wherein preferably the receiving tool and / or the drilling tool has the shape of the surface contour of the working face, and / or wherein the receiving tool preferably radially covers the drilling region of the drill head, and / or that a comminution tool is provided for comminuting the drill cuttings, which has a comminution surface which is movable along the borehole wall, so that between the comminution surface and Boron wall is provided a crushing gap, wherein preferably the crushing gap is adjustable and / or the crushing surface is arranged incident to the borehole wall, and / or the crushing tool is arranged on an outer side of a receiving tool, and / or that at least one receiving tool for receiving on the sole the borehole lying Bohrklein is provided, which has a receiving surface which is opposite the line of flight of the borehole with an angle <20 °, wherein the receiving surface is preferably provided on its radial outer side with a centering surface and / or a crushing surface, and / or Tool holder is arranged so that it is radially adjustable, wherein preferably provided for providing the adjustability spacers.

11. A drill head for expanding a pilot bore for creating a borehole with a borehole wall by loosening a pilot bore surrounding rock in the region of a substantially perpendicular to the pilot bore extending working face with a base body on which a connecting element for a pilot drill string is provided, wherein on the base body at least one tool holder are provided for at least one drilling tool, characterized in that at least one receiving tool is provided which has an engagement region with the working face, on which a drilling tool is arranged, and in that the receiving tool receives the cuttings loosened at the working face and from the drilling area abfördert.

12. Drilling head according to claim 11, characterized in that on the receiving tool at least one rinsing nozzle is provided.

13. Drilling head according to claim 11 or 12, characterized in that the receiving tool and / or the drilling tool has the shape of the surface contour of the working face.

14. Drilling head according to one of claims 11 to 13, characterized in that the receiving tool radially covers the drilling area of the drill head.

15. Boring head according to one of claims 11 to 14, characterized in that at least two tool holders are provided, that at least one tool puller is radially spaced from the main body further than the at least one other tool holder, so that at least one outer and one inner drilling tool are present, which are engageable with the working face, and that the at least one inner drilling tool and the at least one outer drilling tool are each offset at an angle to the working face, wherein the two drilling tools are preferably arranged so that the working face at least one radially encircling wedge-like Recess or at least one radially encircling wedge-like projection and / or, wherein the inner angle between the drilling tools 120 to 150 ° preferably 135 to 140 °, and / or that a rinsing nozzle is provided, from which a flushing medium can be discharged, wherein the rinsing nozzle so is arranged that the Area between the borehole wall and the borehole wall facing outer portion of the drilling tool with the dispensed rinsing medium is flushable, and / or that a crushing tool is provided for crushing the cuttings having a crushing surface which is movable along the borehole wall, so that between crushing surface and borehole wall a comminution gap is provided, wherein preferably the comminution gap is adjustable and / or the comminution surface is arranged incident to the borehole wall, and / or the comminution tool is arranged on an outer side of a receiving tool, and / or that at least one receiving tool is provided for receiving drill cuttings lying on the bottom of the borehole and having a receiving surface which is incident with respect to the alignment line of the borehole at an angle of <20 °, the receiving surface preferably having a centering surface on its radially outer side and / or a comminution surface is provided, and / or that the tool holder is arranged so that it is radially adjustable, wherein preferably provided for providing the adjustability spacers.

16. A boring head for expanding a pilot bore for creating a borehole with a borehole wall by loosening a pilot bore surrounding rock in the region of a substantially perpendicular to the pilot bore extending working face with a base body on which a connecting element for a pilot drill string is provided, wherein on the base body at least one tool holder are provided for at least one drilling tool, characterized in that a crushing tool is provided for crushing the cuttings having a crushing surface which is movable along the borehole wall, so that between crushing surface and borehole wall a crushing gap is provided.

17. Drilling head according to claim 16, characterized in that the crushing gap is adjustable.

18. Drilling head according to claim 16 or 17, characterized in that the crushing surface is arranged incident to the borehole wall.

19. Drilling head according to one of claims 16 to 18, characterized in that the crushing tool is arranged on an outer side of a receiving tool.

20. Drilling head according to one of claims 16 to 19, characterized in that at least two tool holders are provided, that at least one tool puller is radially spaced from the main body further than the at least one other tool holder, so that at least one outer and one inner drilling tool are present, which are engageable with the working face, and that the at least one inner drilling tool and the at least one outer drilling tool are each offset at an angle to the working face, wherein the two drilling tools are preferably arranged so that the working face at least one radially encircling wedge-like Recess or at least one radially encircling wedge-like projection and / or, wherein the inner angle between the drilling tools 120 to 150 ° preferably 135 to 140 °, and / or that a rinsing nozzle is provided, from which a flushing medium can be discharged, wherein the rinsing nozzle so is arranged that the Area between the borehole wall and pointing to the borehole wall outer portion of the drilling tool with the dispensed rinsing medium is flushable, and / or that at least one receiving tool is provided which has an engagement region with the working face on which a drilling tool is arranged, and that the receiving tool to the working face picks up detached drill cuttings and removes them from the drilling area, wherein preferably at least one rinsing nozzle is provided on the receiving tool, and wherein preferably the receiving tool and / or the drilling tool has the shape of the surface contour of the face, and / or wherein the receiving tool preferably the drilling area of the Radially covers drilling head, and / or that at least one receiving tool for receiving lying on the bottom of the drill hole is Bohrklein having a receiving surface, which is opposite the line of flight of the borehole with an angle <20 °, the receiving surface on your radia len outer surface is preferably provided with a centering surface and / or a crushing surface., and / or that the tool holder is arranged so that it is radially adjustable, wherein preferably provided for providing the adjustability spacers.

21. A boring head for expanding a pilot bore for creating a borehole with a borehole wall by loosening a pilot bore surrounding rock in the region of a substantially perpendicular to the pilot bore extending working face with a base body on which a connecting element for a pilot drill string is provided, wherein on the base body at least one tool holder is provided for at least one drilling tool, characterized in that at least one receiving tool for receiving located on the bottom of the well cuttings is provided, which has a receiving surface which is opposite to the alignment line of the borehole with an angle <20 °.

22. Boring head according to claim 21, characterized in that the

Receiving surface is provided on its radial outer side with a centering surface and / or a crushing surface.

23. Drilling head according to claim 21 or 22, characterized in that at least two tool holders are provided, that at least one tool puller is radially spaced from the body further than the at least one other tool holder, so that at least one outer and one inner drilling tool are present with the working face can be brought into engagement, and that the at least one inner drilling tool and the at least one outer drilling tool are each offset at an angle to the working face, wherein the two drilling tools are preferably arranged so that the working face at least one radially encircling wedge-like recess or has at least one radially encircling wedge-like projection and / or, wherein the inner angle between the drilling tools 120 to 150 ° is preferably 135 to 140 °, and / or that a rinsing nozzle is provided, from which a rinsing medium can be delivered, wherein the rinsing nozzle is arranged in that the area between rule Boron wall and the bore hole facing outer portion of the drilling tool with the dispensed rinsing medium is flushable, and / or that a crushing tool is provided for crushing the cuttings having a crushing surface which is movable along the borehole wall, so that between crushing surface and borehole wall a crushing gap is provided, wherein preferably the crushing gap is adjustable and / or the crushing surface is arranged incident to the borehole wall, and / or the crushing tool is arranged on an outer side of a receiving tool, and / or that at least one receiving tool is provided, which has an engagement region with the working face has, on which a drilling tool is arranged, and that the receiving tool receives the dissolved at the working face cuttings and carries away from the drilling area, wherein on the receiving tool preferably at least one rinsing nozzle is provided, and wherein preferably the receiving tool and / or the drilling tool has the shape of the surface contour of the working face, and / or wherein the receiving tool preferably covers the drilling area of the drill head radially, and / or that the tool holder is arranged so that it is radially adjustable, preferably Providing the adjustability spacers are provided.

24. A drill head for expanding a pilot bore for creating a borehole with a borehole wall by loosening a pilot bore surrounding rock in the region of a substantially perpendicular to the pilot bore extending working face with a base body on which a connecting element for a pilot drill string is provided, wherein on the base body at least one tool holder are provided for at least one drilling tool, characterized in that the tool holder is arranged so that it is radially adjustable.

25. Drilling head according to claim 24, characterized in that for the provision of adjustability spacers are provided.

26. Drilling head according to claim 24 or 25, characterized in that at least two tool holders are provided, that at least one

Werkzeugzughalter radially spaced from the body further than the at least one other tool holder, so that at least an outer and an inner drilling tool are present, which are engageable with the working face, and that the at least one inner drilling tool and the at least one outer drilling tool respectively in an angle relative to the working face are arranged offset, wherein the two drilling tool are preferably arranged so that the working face has at least one radially circumferential wedge-like recess or at least one radially circumferential wedge-like projection and / or, wherein the inner angle between the drilling tools 120 to 150 ° preferred 135 to 140 °, and / or that a rinsing nozzle is provided, from which a rinsing medium can be dispensed, wherein the rinsing nozzle is arranged so that the area between the borehole wall and the borehole wall facing outer portion of the drilling tool is flushable with the dispensed rinsing medium, and / or that a comminution tool is provided for comminuting the cuttings, which has a comminution surface which is movable along the borehole wall, so that a comminution gap is provided between the comminution surface and the borehole wall, wherein preferably the comminution gap is adjustable and / or the comminution surface is opposite the borehole wall is arranged incidentally, and / or the crushing tool is arranged on an outer side of a receiving tool, and / or that at least one receiving tool is provided, which has an engagement region with the working face on which a drilling tool is arranged, and that the receiving tool at the working face solves dissolved cuttings and carries away from the drilling area, wherein the receiving tool preferably at least one rinsing nozzle is provided, and wherein preferably the receiving tool and / or the drilling tool has the shape of the surface contour of the working face, and / or wherein the receiving tool preferably radially covers the drilling area of the drill head, and / or that at least one receiving tool for receiving on the bottom of the borehole lying drill cuttings is provided, which has a receiving surface which is opposite the line of flight of the borehole with an angle <20 °, wherein the receiving surface is preferably provided on its radial outer side with a centering surface and / or a crushing surface.

27. Drilling head according to one of claims 1 to 26, characterized in that on the working face facing away from the drill head at least one effective against the borehole wall centering element is present.

28. Boring head according to one of claims 1 to 27, characterized in that the connecting element is designed to be elongated for entry into the pilot bore and / or is designed substantially with a diameter of the pilot drilling stand and / or a centering portion with a substantially the diameter of Pilot bore has identical diameter.

29. Drilling head according to one of claims 1 to 28, characterized in that at least one stabilizing element is provided that has on its outer side a contact portion, plan or radius of the borehole wall, and that the stabilizing element is preferably designed as a receiving tool.

30. Drilling head according to one of claims 1 to 28, characterized in that behind the drill head a centering element according to claim 31 or 32 is provided.

31. Zetrierelement for arrangement behind a drill head, in particular a drill head according to one of claims 1 to 29, with a base body, the connecting elements for mounting the centering element in a drill string , wherein on the base body arranged in a segment of a circle on at least one support member arranged on the base body portions are provided which coincide with the Bohrradius of the drill head, wherein at least a portion has a receiving tool for receiving lying on the bottom of the drill hole cuttings having a receiving surface , which is incident to the alignment line of the borehole at an angle <20 °.

32. Zetrierelement according to claim 31, characterized in that the receiving surface is preferably provided on its radial outer side with a centering surface and / or a crushing surface.

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