EP3039218B1 - Drill head for expanding a pilot bore in order to create a borehole - Google Patents

Description

The application relates to a drill head for expanding a pilot hole for creating a borehole with a borehole wall by loosening a pilot hole 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 the base body at least one tool holder are provided for at least one drilling tool.

From the EP 0 360 321 a so-called HDD (Horizontal Directional Drilling) method 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 Pilot drill string installed. Behind the reamer, a pipeline is provided, which substantially corresponds to the diameter of the pilot drill string. US 3,750,767 discloses another device which is considered as the closest prior art. 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 application is therefore to provide a drill head, in which the wear on the cutting rollers is reduced. According to the application, 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, which is connected to the 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 application provides that the two drilling tools are arranged so that the working face has at least one radially encircling 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 application, 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 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.

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 application, a third solution provides for 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 application 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 application 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 application provides that the comminuting tool is arranged on an outer side of a receiving tool. This provides an efficient way of arranging the tool without additional elements on the drill head. According to the invention, a fifth solution provides for the task of providing at least one receiving tool for receiving drill cuttings located on the bottom of the drill hole, which has a receiving surface which is opposite the alignment line of the drill bit Borehole with an angle <20 ° occurs.

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 application provides that the receiving surface is provided on its radially outer side with a centering surface and / or a crushing surface. According to the application, 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 the caliber To allow drilling head with the new cutting rollers.

A preferred teaching of the application 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.

Another teaching of the application 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 application provides that the connection 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 application provides that at least one stabilizing element is provided, that on its outside 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.

Another teaching of the application provides that behind the drill head, a centering element described below is provided. According to the application, a further solution of the problem provides that behind a drill head, in particular a drill head of the embodiment described above, a Zetrierelement is arranged with a base body, the connecting elements for mounting the centering in a drill string, wherein on the base body like a circle segment 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 application 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 application will be described in more detail below with reference to a preferred embodiment in conjunction with a further drawing.

Fig. 1

eine erste räumliche Ansicht eines Bohrkopfes in einem Bohrloch,

Fig. 2

eine zweite räumliche Ansicht zu Fig. 1,

Fig. 3

eine weitere räumliche Ansicht des Bohrkopfes,

Fig. 4

eine teilgeschnittene räumliche Seitenansicht des erfindungsgemäßen Bohrkopfes und eine teilgeschnittene räumliche Seitenansicht des durch den Bohrkopfes hergestellten Bohrlochs,

Fig. 5

eine Ausschnittansicht zu Fig. 4, ohne umgebendes Bohrloch,

Fig. 6

eine geschnittene Teilansicht des Bohrkopfes,

Fig. 7

eine weitere Teilansicht des Bohrkopfes,

Fig. 8

ein Werkzeughalter mit Bohrwerkzeug des Bohrkopfes in erster Stellung,

Fig. 9

eine zweite Stellung zu Fig. 8,

Fig. 10

einen Stabilisator in teilgeschnittener Ansicht,

und

Fig. 11

eine Schnittansicht zu Fig. 10.

Show

Fig. 1

a first spatial view of a drill head in a borehole,

Fig. 2

a second spatial view too Fig. 1 .

Fig. 3

another spatial view of the drill head,

Fig. 4

a partially cutaway side view of the drill head according to the invention and a partially sectioned spatial side view of the wellbore produced by the drill head,

Fig. 5

a cutout view too Fig. 4 , without surrounding borehole,

Fig. 6

a sectional partial view of the drill head,

Fig. 7

another partial view of the drill head,

Fig. 8

a tool holder with a drilling tool of the drill head in the first position,

Fig. 9

a second position too Fig. 8 .

Fig. 10

a stabilizer in a partially cutaway view,

and

Fig. 11

a sectional view too Fig. 10 ,

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 in Fig. 1 it can be seen, the wellbore 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 103.

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 seen from the right figure of Fig. 4 it can be seen, the working face 103 has a V-shaped break-in 105, which radially around the pilot hole 102nd 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 played. 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, broaching tools 25 are provided on the carrier ring 13, which have an elongate base body 26 (see FIG 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 broaches 25 take over the wear plates 27, 28 drill cuttings 109, in particular, on the sole 113 of the well, with, carry them, as in Fig. 11 is shown, along the borehole wall 104 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 cuttings 109 pass into a flow area 110, in which a higher speed of Borspülung than at the outer areas of the borehole wall 104 prevails, whereby the cuttings 109 is taken back into the flow, as this in Fig. 10 is shown.

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 in Fig. 6 is shown, a crushing 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 opposite the borehole wall 104 at an angle a, as in FIG Fig. 6 represented, incident arranged. 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 in 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 in Fig. 8 shown) and a second position (as in Fig. 9 shown) 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 in Fig. 10 shown, 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 broach 44 is the cuttings 109, as in 10 and 11 shown, taken along, transported to the highest hole 111, from where then the cuttings 109 falls into the flow region 110 of the drilling mud and so the discharge of cuttings 109 is returned from the wellbore 100. Part of the cuttings 109 will become, as in Fig. 10 shown again settle on the bottom hole 113. 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, can on the stabilizing portion 43 on both sides, as in Fig. 11 represented, a corresponding broaching be provided. LIST OF REFERENCE NUMBERS 10 wellhead 37 rinsing nozzle 11 body 38 spacer 12 crossmember 39 drill string 13 support ring 40 centering 14 toolholder 41 body 15 cutting roller 42 crossmember 16 tooth 43 stabilizer section 17 connection 44 reamer 18 connection 45 receiving surface 19 stabilizer 100 well 20 rinsing nozzle 101 Soil / rock 21 outer row of teeth 102 pilot hole 22 Reaming tool / picking tool 103 working face 104 borehole wall 23 drilling 105 V-shaped burglary 24 rinsing nozzle 106 Thighs, outside 25 Reaming tool / picking tool 107 Thighs, inside 108 gap 26 body 109 cuttings 27 wear plate 110 flow region 28 wear plate 111 Highest borehole 29 stabilizer surface 112 crushing gap 30 wear plate 113 bottomhole 31 driving region α angle of incidence 32 chopping tool 33 crushing surface 34 wear plate 35 retaining ring 36 diagonal strut

Claims (14)

1. Drill head (10) for expanding a pilot bore (102) in order to create, by the HDD method, a borehole (100) having a borehole wall (104), by loosening rock (101) which surrounds the pilot bore in the region of a working face (103) which extends substantially at right angles to the pilot bore, comprising a basic body (11) on which a connection element (17) for a pilot bore string is provided, wherein at least two tool holders (14) for in each case at least one drilling tool are provided 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 (14), so that at least one outer and one inner drilling tool (15) are present which can be brought into engagement with the working face (103), that the at least one inner drilling tool (15) and the at least one outer drilling tool (15) are each offset at an angle relative to the working face (103), characterised in that at least one receiving tool (22) is provided which has an engagement region (105) with the working face (103), on which engagement region a drilling tool (23) is positioned, and in that the receiving tool (22) receives the drill cuttings loosened at the working face (103) and removes them from the drilling region, and in that at least one receiving tool (25) is provided for receiving drill cuttings (109) located on the bottom (113) of the borehole, which receiving tool has a receiving surface at an inclination angle of < 20° with respect to the alignment line of the borehole.
2. Drill head according to Claim 1, characterised in that the two drilling tools (15) 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, and/or in that the inside angle between the drilling tools is 120 to 150°, preferably 135 to 140°.
3. Drill head according to Claim 1 or 2, characterised in that a flushing nozzle (20, 24) is provided, from which a flushing medium can be discharged, the flushing nozzle being arranged so that the region between the borehole wall and the outer portion of the drilling tool directed towards the borehole wall is flushable with the flushing medium which has been discharged.
4. Drill head according to any one of Claims 1 to 3, characterised in that at least one flushing nozzle is provided on the receiving tool (22).
5. Drill head according to any one of Claims 1 to 4, characterised in that the receiving tool and/or the drilling tool has the form of the surface contour of the working face (103).
6. Drill head according to any one of Claims 1 to 5, characterised in that the receiving tool (22) radially covers the drilling region of the drill head.
7. Drill head according to any one of Claims 1 to 6, characterised in that a crushing tool (32) is provided for crushing the drill cuttings, which has a crushing surface (33) which is movable along the borehole wall so that a crushing gap is provided between the crushing surface and the borehole wall.
8. Drill head according to Claim 7, characterised in that the crushing gap (112) is adjustable and/or the crushing surface is arranged at an angle with respect to the borehole wall, and/or the crushing tool is arranged on an outer surface of a receiving tool.
9. Drill head according to any one of Claims 1 to 8, characterised in that the receiving surface is provided on its radial outer surface with a centring surface and/or a crushing surface.
10. Drill head according to any one of Claims 1 to 9, characterised in that the tool holder (14) is arranged so that it is radially adjustable.
11. Drill head according to Claim 10, characterised in that spacers (38) are provided to facilitate the adjustability.
12. Drill head according to any one of Claims 1 to 11, characterised in that at least one centring element (40) which is effective in respect of the borehole wall is present on the side of the drill head remote from the working face.
13. Drill head according to any one of Claims 1 to 12, characterised in that the connection element (17) is elongated with respect to the entry into the pilot bore and/or is configured substantially to the diameter of the pilot bore and/or it has a centring portion of a diameter which is substantially identical to the diameter of the pilot bore.
14. Drill head according to any one of Claims 1 to 13, characterised in that at least one stabilising element (19) is provided which has on its outer surface a contact portion, flat or with the radius of the borehole wall, and in that the stabilising element is preferably configured as a receiving tool.

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