EP3333356A1 - Rotary drilling tool and method for creating a hole in the soil - Google Patents

Abstract

The invention relates to a rotary drilling tool and a method for creating a bore in the ground, in which soil material is removed by means of a removal device on an underside of a base body of the rotary drilling tool, by means of a feeding device scavenging air is fed into the hole filled with drilling slurry in the region of the ablation device and by means the scavenging air removed soil material is conveyed away through a discharge line. According to the invention, the soil material is conveyed to a receiving area, which is arranged in an upper portion of the base body. Above the receiving area a collecting hood is provided, which closes the receiving area upwards to form an air collecting space in which air accumulates. At the collecting hood a drain valve is arranged, with which air is discharged from the air collecting space.

Description

The invention relates to a rotary drilling tool for creating a bore in the ground with a base body, arranged on an underside of the body Abtragseinrichtung for removing soil material, a feeder for supplying scavenging air in the region of the Abtragseinrichtung and a discharge line for discharging abraded soil material and drilling suspension, which are conveyed by means of the scavenging air in the receiving area, according to the preamble of claim 1.

The invention further relates to a method for producing a bore with a rotary drilling tool, in which soil material is removed by means of a removal device on an underside of a base body of the rotary drilling tool, by means of a feed device scavenging air is fed into the bore filled with drilling slurry in the region of the ablation device and by means of Rinsing air removed soil material is conveyed away through a discharge line, according to the preamble of claim 11.

A generic rotary drilling tool is from the EP 2 592 214 A1 known. The removed soil material is removed by means of scavenging air via a discharge line from the wellbore. For large drilling depths there is a high demand for compressed air as purge air.

A core drilling tool with inner and outer coils for generating a scavenging flow goes out of the DE 20 02015 102 848 U1 out.

In such a rotary drilling tool, it is fundamentally advantageous that the scavenging air can be used in two ways. First, the purge air is used for flushing the removal device, in particular of roller bits during the removal of hard rock. It is essential for the functioning of roller chisels that they can act directly on the pending floor. At the same time, the scavenging air serves as a conveying medium to convey the excavated soil up to the receiving space on the rotary drilling tool.

In the known rotary drilling tools and methods, the scavenging air continues to flow upward through the drilling slurry in the wellbore even as the soil material gradually settles into the receiving space on the rotary drilling tool. The upward flowing air can loosen soil material from the bore wall and destabilize it.

The invention has for its object to provide a rotary drilling tool and a method for creating a hole in the ground, with which a hole can be made efficiently when using scavenging air.

According to the invention, the object is achieved on the one hand by a drilling tool having the features of claim 1 and on the other hand by a method having the features of claim 11. Preferred embodiments of the invention are specified in the respective dependent claims.

The rotary drilling tool according to the invention is characterized in that the removed soil material is conveyed to a receiving area, which is arranged in an upper portion of the base body, that above the receiving area a collecting hood is provided, which closes an air collecting space above the receiving area upwards, and that at Collection hood a drain valve is arranged, which is designed for targeted removal of air from the air collection chamber.

The removed soil material is carried away by means of the introduced scavenging air from the bottom of the hole and can settle in an upper region of the rotary drilling tool in a receiving space. Upon reaching a certain filling the rotary drilling tool is pulled out of the hole and emptied to the ground surface. Subsequently, the drilling process can be continued.

The invention is based on the recognition that scavenging air flowing freely upwards can also pull soil material upwards out of the bore wall. This can make the bore wall unstable. In particular, when using a bentonite solution, a bentonite film forms on the bore wall. This bentonite film has a stabilizing effect on the bore wall. In particular, this stabilizing bentonite film can be damaged by scavenging air flowing upwards and the overall stability of the bore can thus be impaired.

The inventive construction of the rotary drilling tool solves this problem comprehensively. The upward purging air is collected above the receiving area via a collecting hood with an air collecting space. Thus, the scavenging air can not flow further up the borehole wall.

According to a further aspect of the invention, a drain valve is provided on the collecting hood with which air can be purposely removed from the air collecting space at specific times or under certain circumstances.

Another advantage of the invention can be seen in the fact that the air thus collected and discharged basically used again and can be routed back into the bore as scavenging air. This scavenge air cycle is particularly environmentally friendly. On the outer circumference of the collecting hood, an annular seal, in particular an inflatable annular seal, may be provided to seal a gap to the borehole wall.

A preferred embodiment of the invention is that the drain valve is connected to an exhaust duct, with which air can be discharged from the bore to the bottom surface. The exhaust duct may be a hose or a pipe. As a result, the trapped air is discharged reliably upwards without contact with the borehole wall.

In principle, the drain valve can be actuated by an operator, for example in a drill. According to one embodiment of the invention, it is advantageous that a control device is provided for the controlled actuation of the drain valve. The control device may have sensors, such as level or pressure sensors, at a suitable time or state for discharging To determine air. Preferably, the control device has a sensor which actuates the control device for opening the drain valve when a predetermined level in the collecting hood is reached. When a predetermined condition is reached, a discharge of air can then be carried out automatically by the control device.

It is particularly expedient according to a variant that the control device has a float which floats at the interface between a drilling suspension and a scavenging air under the collecting hood, wherein upon reaching a predetermined level in the collecting hood by the float, the control means for opening the drain valve actuated is. With increasing operation, more and more air collects under the collecting hood. As a result, the float, which floats at the interface between the drilling slurry and the air collecting space, is gradually lowered. Upon reaching a lower threshold level of the float, the control device is actuated, wherein the drain valve is opened. The opening of the drain valve can be made until the float reaches an upper limit or an upper level again. Then, the drain valve can be closed again by means of the control device.

The rotary drilling tool according to the invention is further developed in that a supply line for scavenging air is provided, which leads from outside the borehole to the underside of the base body with the removal device. In particular, from outside the borehole by means of a compressor continuously scavenging air can be supplied into the borehole to the ablation device. The supply line can have a plurality of outlet openings on the annular removal device in order to convey soil material from the bottom of the hole as extensively as possible.

In principle, the removal device can be designed in any desired manner. According to one embodiment variant of the invention, it is particularly preferred that the removal device has at least one rotatably mounted roller chisel and / or at least one stationary round-shank chisel and / or at least one stationary ablation tooth.

A preferred development of the invention is also that a plurality of rotatably mounted roller bits and / or fixed round shank chisel and / or fixed Abtragszähne are attached to the underside of the body. By combining different removal elements, a particularly good drilling progress can be achieved even in changing soil conditions.

It can also be provided active removal tools, preferably axially movable hammers for working the soil material. By supplying energy, such as compressed air or a hydraulic fluid, they exert an axial impact movement on the upcoming, hard soil material.

A further expedient embodiment of the invention consists in that a connecting device for connecting the rotary drilling tool to a drilling drive means is arranged above the collecting hood. The connecting device may in particular be designed as Kellybox, with which a drill string, in particular a Kelly rod for transmitting a torque and a feed force, can be releasably and non-positively attached. The connecting device can be arranged centrally on the top of the collecting hood. The rotary drilling tool can thus be used on conventional drilling rigs. It may be provided a center shaft, at the upper end of the connecting device is mounted to transmit torque. Preferably, the collecting hood is mounted axially adjustable on the center shaft.

According to one embodiment of the invention, it is advantageous that the rotary drilling tool is a core drill, which is designed to produce a core and for receiving the core in the interior of the tubular body. The soil material is expediently worked off annularly by the removal device, which has an annular configuration with cutting means or removal elements. In a particularly efficient manner, a cylindrical drill core is thereby produced in the borehole through the annular removal of solid soil material.

Preferably, a core is held frictionally in the interior of the body by means of a Kernfangeinrichtung and further separated by force from the bottom hole. The core can be accessed via a separate tool or be conveyed together with the rotary drilling tool to a ground surface.

The invention further includes a drilling apparatus for making a hole in the ground with a mast and a drill drive for rotatably driving a rotary drilling tool, wherein the rotary drilling tool is configured as set forth above. By connecting the rotary drilling tool according to the invention with a drill drive, which is mounted on a mast of a drill and rotatably drives the rotary drilling, boreholes can be achieved with such a drill particularly efficient in the ground and in all upcoming soil materials and basically in all technically achievable depths.

With regard to the method, the abovementioned object is achieved according to the invention in that the removed soil material is conveyed to a receiving area, which is arranged in an upper portion of the base body, that above the receiving area a collecting hood is provided, which the receiving area up to form an air collecting space terminates, in which air accumulates, and that a discharge valve is arranged on the collecting hood, with which air is discharged from the collecting space.

With the method according to the invention, the advantages described above can be achieved. Preferably, the method is carried out with the rotary drilling tool described above, which has a collecting hood with an air collecting space above a receiving space for the removed soil material. The collecting hood is preferably conical or dome-shaped, wherein the discharge valve for discharging the air is arranged on an upper tip.

A preferred embodiment of the method according to the invention consists in that the discharge valve is opened and closed controlled by a control device. Automatic control ensures that air is reliably removed from the rotary drilling tool and that the specified level levels within the rotary drilling tool are not exceeded or fallen below.

Fig. 1

eine perspektivische Ansicht eines erfindungsgemäßen Drehbohrwerkzeugs;

Fig. 2

eine Querschnittsansicht des Drehbohrwerkzeuges von Fig. 1; und

Fig. 3

eine Seitenansicht des Drehbohrwerkzeuges der Figuren 1 und 2 mit verschiedenen Positionen der Auffanghaube.

The invention will be further elucidated on the basis of a preferred exemplary embodiment, which is illustrated schematically in the attached drawings. In the drawings show:

Fig. 1

a perspective view of a rotary drilling tool according to the invention;

Fig. 2

a cross-sectional view of the rotary drilling tool of Fig. 1 ; and

Fig. 3

a side view of the rotary drilling tool the FIGS. 1 and 2 with different positions of the collecting hood.

An inventive rotary drilling tool 10 for creating a hole in the ground is described below in connection with the FIGS. 1 and 2 explained. The rotary drilling tool 10 has a main body 12 with a removal device 20 on the underside of the main body 12. The cylindrical base body 12 is tubular with a central drill core receptacle 14. The removal device 20 is annularly formed with a plurality of disc-shaped hammers 22. The hammers 22 are designed as so-called air hammers, which are moved axially back and forth via supply of compressed air, wherein for the removal of hard soil material impact pulses are exerted on the upcoming soil.

The rotary drilling tool 10 has on a top side of the main body 12 a central drill pipe 40 with an upper connecting device 42, which is designed as a so-called Kellybox. This serves to connect further drill string elements in order to transmit torque from a drill, not shown, to the rotary drilling tool 10.

By means of a feed device 30, compressed air is supplied to the main body 12 by the drill. Compressed air is fed into an inner conduit 44 in the drill string 40 via an upper supply conduit 32. Via an intermediate line 34, the inner conduit 44 is conductively connected in the drill string 40 with a transverse channel 35 in the base body 12. From the transverse channel 35, the compressed air can be further passed through a central tube 36 on the base body 12 to a transverse distribution line 38 and then to the vertically extending distribution lines 39, which lead to the drive units of the hammers 22.

The compressed air used in operating the hammers 22 is passed to convey off the processed soil material in the suspension-filled bore. The discharged at lower end portions of the hammers 22 pressurized fluid passes the removed soil material to discharge openings 24 at the bottom of the body 12. From the discharge openings 24, the removed soil material with the exiting purge air and sucked drilling suspension vertically upward through a discharge line 25 to the upper end of the flow cylindrical body 12. To support the flow and a suction effect 26 compressed air can flow directly from the vertical distribution line 39 into the vertical discharge line 26 via one or more connecting channels.

At the upper end of the discharge lines 25, manifolds 28 are provided with downwardly directed outlet openings, so that the discharged soil material is directed downward directed into a cylindrical receiving area 18 on the base body 12. In this receiving area 18, the solid components of the discharged suspension can sediment down on an intermediate bottom 16 of the rotary drilling tool 10. Conversely, air exiting the manifolds 28 may flow upward along the drilling axis.

According to a finding of the invention, the free upwardly flowing air can lead to destabilization of the bore wall of the created bore. To counteract this, in the rotary drilling tool 10 according to the invention along a cylindrical guide section 41 of the drill string 40, a collecting hood 50 with a sliding sleeve 51 is mounted so as to be vertically displaceable and rotatable. The collecting hood 50 has a circular inlet region 53 whose outer diameter substantially corresponds to the bore diameter. The collecting hood 50 encloses an air collecting space 52, in which upwardly flowing air is taken up. An upper region of the collecting hood 50 is provided with a taper 54, which opens into an exhaust air line 62 with a discharge valve 60. The collecting hood 50 is rotatably mounted relative to the main body 12. Alternatively, this may also be rotatably connected to the base body 12.

The discharge valve 60 is initially closed until a sufficient amount of air has accumulated in the air collecting space 52 of the collecting hood 50. By means of a controller, not shown, at certain times or when reached a certain air pressure or an amount of air in the collecting hood 50, the drain valve 60 is opened, so that air controlled by the exhaust duct 62 can flow out of the bore upwards.

In order to reliably prevent air from escaping around the collecting hood 50, an inflatable annular seal 58 is preferably provided on an outer periphery of a cylindrical portion of the collecting hood 50. The inflatable ring seal 58 is supplied with compressed air via a supply line 57, which are formed in the embodiment shown as simple openings to the air collection chamber 52. A rise in pressure in the air collection chamber 52 results in a corresponding tight inflation of the annular seal 58. Alternatively or additionally, a compressed air supply line can be provided from the outside, so that the inflatable ring seal 58 can be actuated at any time by means of a controller.

With the ring seal 58, in principle, the entire lower region of the bore below the collecting hood 50 can serve as an air collecting space 52. To increase this air collection chamber 52, the collecting hood 50 can be adjusted vertically along the guide portion 41 of the drill string 40, as clearly in Fig. 3 is shown. The adjustment can be done by an adjusting device, not shown, for example by means of an adjusting cylinder, or automatically in operation by the ascending and accumulated air in the collecting hood 50.

Claims (12)

Rotary drilling tool for creating a hole in the ground with a base body (12), a removal device (20) arranged on an underside of the base body (12) for removing soil material, - A feeder (30) for supplying scavenging air in the region of the removal device (20) and a discharge line (25) for discharging removed soil material and drilling suspension, which can be removed by means of the scavenging air,
characterized, that a receiving area (18) for receiving the removed soil material from the discharge line (25) is provided in an upper portion of the base body (12), - That above the receiving area (18) a collecting hood (50) is arranged, which closes an air collecting space (52) above the receiving area (18) upwards, and - That at the collecting hood (50) a discharge valve (60) is arranged, which is designed for the targeted removal of air from the air collecting space (52). Rotary drilling tool according to claim 1,
characterized,
in that the discharge valve (60) is connected to an exhaust air line (62), with which air can be discharged from the bore to the ground surface. Rotary drilling tool according to claim 1 or 2,
characterized,
in that a control device is provided for the controlled actuation of the drain valve (60). Rotary drilling tool according to claim 3,
characterized,
in that the control device has a sensor which, upon reaching a predetermined fill level in the collecting hood (50), actuates the control device for opening the drain valve (60). Rotary drilling tool according to one of claims 1 to 4,
characterized,
that a supply line (32) is provided for flushing air, which leads from outside the borehole to the underside of the base body (12) with the Abtragseinrichtung (20). Rotary drilling tool according to one of claims 1 to 5,
characterized,
that the Abtragseinrichtung (20) has at least one rotatably mounted roller bits, and / or at least one stationary round shank chisels and / or at least one fixed Abtragszahn. Rotary drilling tool according to one of claims 1 to 6,
characterized,
that the Abtragseinrichtung (20) axially movable hammers (22). Rotary drilling tool according to one of claims 1 to 7,
characterized,
in that a connecting device (42) for connecting the rotary drilling tool (10) to a drilling drive means is arranged above the collecting hood (50). Rotary drilling tool according to one of claims 1 to 8,
characterized,
in that the rotary drilling tool (10) is a core drill, which is designed to produce a core and to receive the core inside the tubular base (12). Drill for creating a hole in the ground with a mast and a drill drive for rotatably driving a rotary drilling tool (10),
characterized,
in that a rotary drilling tool (10) according to one of claims 1 to 9 is provided. A method for creating a hole in the ground with a rotary drilling tool (10), in particular according to one of claims 1 to 9, in which - With a removal device (20) on an underside of a base body (12) of the rotary drilling tool (10) soil material is removed, - By means of a feeder (30) scavenging air is fed into the hole filled with drilling slurry in the region of the removal device (20) and - Ground material removed by means of the scavenging air via a discharge line (25)
is carried away,
characterized, - That the removed soil material is conveyed to a receiving area (18) which is arranged in an upper portion of the base body (12), - That above the receiving area (18) a collecting hood (50) is provided, which closes the receiving area (18) upwards to form an air collecting space (52) in which air accumulates, and - That at the collecting hood (50) a discharge valve (60) is arranged, with which air is discharged from the air collecting space (52). Method according to claim 11,
characterized,
that the drain valve (60) controlled by a control device is opened and closed.

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