EP0522446B1 - Method for controlling the direction of an earth drilling apparatus and device for making bore holes - Google Patents

Description

The invention relates to a method for directional controls of an earth drilling device according to the preamble of claim 1 or claim 2 and an earth drilling device for performing an aforementioned method.

For laying cables and hoses in the ground, small tunnels in the diameter range of approx. 45 to 200 mm are required in front gardens, under streets, railways, rivers and paved surfaces, which are often manufactured using impact or impact drills. The displacement heads of conventional devices of this type can have good displacement and shattering properties due to special head shapes. However, they cannot be controlled in their feed direction, so that with simple devices of this type there is no possibility of controlling these devices around the curve or correcting course deviations of the devices.

Various solutions have already been proposed to overcome this disadvantage. It is known from DE-A-39 11 467 to provide a bevel on the end face of an earth drilling device. This bevel pushes the head of the device away from one side when penetrating the floor. In order to achieve straight running, such a head must be rotated continuously around its longitudinal axis. The bevel presses alternately up, right, down and left during the forward movement of the device, so that the device moves straight when the head is rotated uniformly. However, a head with such a bevel no longer has the necessary smashing and displacement properties to enable forward movement even in inhomogeneous and solid soil types.

In order to reduce the peak resistance on the device head in certain cohesive and sandy soil types and to facilitate the forward movement of the device, it has already been proposed to loosen the soil directly in front of the device head by a strong liquid jet or to completely wash it away. From US-A-4 674 579 an earth drilling device with a drilling head is known which is asymmetrical at the front and has an outlet for a liquid jet which is inclined on one side at an angle to the device axis. Since the soil in the area of the liquid jet is softened or washed away, the earth provides the least resistance to the earth drilling rig in this area. The earth drilling machine is therefore deflected in the direction of the liquid jet during its advance. This allows you to influence the feed direction of the device. For straight running, however, this drill head must be tapered, as is the case with the device described above rotated continuously. A disadvantage of this solution, however, is that the mechanism required to rotate the head does not withstand the harsh operating conditions for long. This would apply in particular to so-called ram boring machines, in which the dynamic hammer blows required to move the earth boring machine are so hard that the elements for guiding and rotating the head would be worn out in a short time.

The same disadvantages have an earth drilling machine with a symmetrical head, known from US-A-4,714,118, on which several asymmetrically arranged jet nozzles are provided. These nozzles are either all open or all closed. The drill head must be turned again to run straight.

From US-A-3 365 007 an earth drill is known, in the drill head of which nozzles are formed for the discharge of a drilling fluid. The liquid discharge through the nozzle can be controlled. Since the drill head must be rotated to penetrate the ground, it must be stopped to change the drilling direction. After the drill head has stopped, the floor is washed away at the desired location by activating certain nozzles. When the drill is put back into operation, it penetrates the flushed cavity and thus deviates from the previous drilling direction in the desired direction. A change of direction during the advance is not possible.

An earth drill according to US Pat. No. 3,746,108 also has the same disadvantage. It differs from the solution known from US Pat. No. 3,365,007 in that the jet nozzles are arranged asymmetrically on the drill head and cannot be controlled selectively. To be able to change the drilling direction, the drill head must be stopped again and aligned so that the nozzles point in the desired direction. After flushing out a lateral cavity, drilling can then be resumed.

US-A-4 930 586, which corresponds to the combination of features in the preambles of claim 1 and claim 2, describes an earth boring device with a drill pipe which has a rounded nose at its propulsion end. A nozzle opening is arranged in this nose, through which an essentially axially directed jet of drilling fluid emerges. The drilling is made solely by this drilling fluid. Furthermore, four nozzles are arranged in the drill pipe just behind the rounded nose so that their axes are perpendicular to the axis of the drill pipe and perpendicular to each other. Drilling fluid for controlling the head end of the drill pipe can escape through these nozzles. The dispensing of the liquid is controlled by solenoid valves. The information about the position of the drill head and the control nozzles is determined with the help of roll and tilt sensors which are arranged in the drill head. The drill head is controlled by the recoil of the drilling fluid emerging from the respective nozzle.

The invention has for its object to provide a method of the type mentioned and an earth drill for its implementation, in which the direction of advance of the earth drill can be changed as desired even in inhomogeneous and solid soils without the head of the earth drill being rotatable about its axis got to.

This object is achieved in a method of the type mentioned by the features specified in the characterizing part of claim 1 or in the characterizing part of claim 2.

In the solution according to the invention, the directional control of the earth drilling device is thus effected in that the pressure fluid for each nozzle is controlled individually with regard to the pressure and / or amount of the pressure fluid. Through the selection of the jet nozzles pressurized with hydraulic fluid and / or the choice of pressure, the degree of loosening of the soil can be carried out in a certain angular range around the head of the earth drilling machine in such a way that a large or small change in direction of the Earth drilling device can be triggered, since in the loosened soil the resistance opposite the head of the earth drilling device is reduced and the displacement head of the earth drilling device inevitably dodges to the side of the lower resistance.

Preferably, further jet nozzles are arranged in the tubular housing, which - viewed in the longitudinal direction of the earth boring device - are in alignment with at least one jet nozzle of the head and are each pressurized with hydraulic fluid in the same way as the jet nozzles in alignment with them Head. Thus, the base is loosened up by the pressure fluid for a change of direction not only in the area of the head but also in the area of the housing. At the same time, the soil is loosened to a greater length, so that the earth drill can be deflected over a shorter tunneling section, i.e. curves with smaller radii can be achieved for the path of the earth drilling rig.

Since the head does not need to be rotated in the ram boring machine according to the invention, the ram boring machine can be driven through the nozzles during the discharge of the pressure fluid. This achieves a high rate of advance.

The pressure of the pressure fluid at the nozzles pointing in the desired direction of deflection can vary between approximately 20 and 250 bar, depending on the type of floor. In order to facilitate the advance of the earth drilling rig by improving its sliding properties, a hydraulic fluid can be used that has thixotropic or lubricant properties.

An earth boring device for performing a method of the type described above is specified in claim 6. In addition to changing the pressure or the amount of pressure fluid, it can also be provided that the respective jet angle of the nozzle is adjustable.

In order to be able to loosen up a larger area of the earth in a given direction, if necessary, it is expedient if a plurality of nozzles are arranged one behind the other in the longitudinal direction of the earth drilling device. In particular when the jet angle of the nozzles can be changed, this results in a large variety of control options.

For the device to run perfectly straight, it is expedient if the nozzles are arranged symmetrically with respect to the longitudinal axis of the earth drilling device. When all nozzles are shut off or all nozzles are pressurized with the same amount of hydraulic fluid and the same pressure, the device is guaranteed to run straight, provided the soil is reasonably homogeneous.

With the exception of the arrangement of the nozzles, the head of the earth drilling device can be designed in a conventional manner. For example, the head can be conical in shape and have grooves distributed symmetrically with respect to the axis, in which the nozzles are arranged, over the conical surface. In contrast to this pure displacement head the head can also be stepped and also have longitudinal grooves distributed symmetrically with respect to the axis, in which the nozzles are in turn arranged. The stepped head has better smashing properties.

To supply the hydraulic fluid to the nozzles, these are expediently connected to axially parallel channels running in the housing wall, the ends of which are connected to the hydraulic fluid source via flexible lines. As a result, the interior of the housing of the earth drilling device remains free in order to accommodate the percussion piston of a ramming device in this space. The control valves for controlling the hydraulic fluid supply to the individual nozzles can either be provided in the earth drilling machine itself or on the hydraulic fluid source. The latter embodiment has the advantage that the control lines for controlling the valves are short and do not have to be pulled along with the earth drilling machine.

The earth drilling device can be pressed into the ground in a manner known per se via a rod engaging at its end remote from the head, wherein a vibration damper can be installed between the earth drilling device and the rod to protect it from damage from blows from the ramming device.

In order to enable the ram boring machine to be used under water, it is expedient if the exhaust air from the pneumatic ramming device is discharged backwards through a watertight line.

In order to be able to correctly determine and monitor the position and orientation of the earth drilling machine at any time, the head of the earth drilling machine can be in it is known to provide a transmitter which emits suitable position signals.

Figur 1

eine schematische Darstellung der Arbeitsweise und des Einsatzes eines als Rammbohrgerät ausgebildeten Erdbohrgerätes,

Figur 2

eine der Figur 1 entsprechende Darstellung eines statischen Erdbohrers,

Figur 3

einen die Achse enthaltenden Schnitt durch ein Rammbohrgerät gemäß Figur 1,

Figur 4

eine Seitenansicht eines konischen Kopfes des erfindungsgemäßen Erdbohrgerätes,

Figur 5

eine Frontansicht des in Figur 4 dargestellten Kopfes,

Figur 6

eine Detaildarstellung einer einzelnen Düse des in Figur 4 dargestellten Kopfes in vergrößertem Maßstab,

Figur 7

eine perspektivische Ansicht eines abgestuften Kopfes eines erfindungsgemäßen Erdbohrgerätes und

Figur 8

eine die Achse enthaltenden Schnitt durch einen Schwingungsdämpfer zwischen einem Rammbohrgerät gemäß Figur 3 und einem Vortriebsgestänge und

Figur 9 und 10

jeweils eine schematische Schnittdarstellung einer Düse.

Further features and advantages result from the following description, which in connection with the accompanying drawings explains the invention with reference to an embodiment. Show it:

Figure 1

1 shows a schematic representation of the mode of operation and the use of an earth drilling device designed as a ram boring machine,

Figure 2

1 shows a representation of a static earth auger,

Figure 3

FIG. 2 shows a section through a ram boring machine according to FIG. 1 containing the axis,

Figure 4

a side view of a conical head of the earth boring machine according to the invention,

Figure 5

3 shows a front view of the head shown in FIG. 4,

Figure 6

3 shows a detailed illustration of an individual nozzle of the head shown in FIG. 4 on an enlarged scale,

Figure 7

a perspective view of a stepped head of an earth drilling device according to the invention and

Figure 8

a section containing the axis through a vibration damper between a ram boring machine according to Figure 3 and a propulsion linkage and

Figures 9 and 10

each a schematic sectional view of a nozzle.

In Figure 1, generally 10 denotes an earth boring device, with the help of which a tube 14 is to be produced in the soil 12, in which cable or hoses can then subsequently be laid. The earth drilling device 10, which will be described in more detail later with reference to FIG. 3, is a ram drilling device which is driven through the soil 12 by the impacts of a percussion piston which is axially movable in the cylindrical housing of the earth drilling device 10. The percussion piston is driven by compressed air, which is supplied from a compressed air source 18 via a hollow rod 16. The linkage 16 also serves to exert a further driving force on the earth drilling device 10. On a drill carriage 20, which is only shown schematically, the linkage is extended in accordance with the advance of the earth boring machine 10 and the propulsive force is introduced. The pits 22 and 24 shown in the drawing serve as a connecting pit or start and entry pit for the earth drilling machine 10 and the linkage 16.

The arrangement described so far is known per se and its technical features and its mode of operation need not be described in more detail. In the conventional devices of this type, the problem basically arises of how the desired direction of advance of the earth drilling device 10 can be maintained or changed in the desired manner. For illustration this problem, a pipe 26 lying in the ground 12 was drawn in, which crosses the pipe 14 to be manufactured and therefore has to be passed under by the earth drilling device 10. Such an evasive maneuver presupposes that the earth drilling device 10 can be controlled accordingly. In the present invention, this is done in that nozzles are arranged on the head of the earth boring machine, generally designated 28, through which liquid is directed in a specific direction at a pressure between 20 and 250 bar, which is also via the linkage 16 or is supplied via its own pressure lines, can be sprayed into the soil, as indicated in Figure 1 by arrows 30 on the head 28 of the earth drilling machine. The pressure is loosened or washed away by the pressure fluid jet, so that it presents the earth drilling device 10 with less resistance in this area. The earth boring machine 10 is deflected when it propels into the area of lower resistance.

The exact design of the earth drilling device will now be explained in more detail with reference to FIGS. 3 to 8.

The ram boring machine shown schematically in FIG. 3 in a section containing the axis comprises a housing, generally designated 32, with a cylindrical section 34 and a conical head 36. At its end remote from the head, the housing 32 is closed by a closing part 38, which extends into the cylindrical section 34 is screwed in.

A percussion piston 40 is guided axially displaceably in the housing 32. At its end facing away from the head 36, the percussion piston 40 has a blind bore 42 into which a control tube 44 engages, which is screwed to the closure part 38 and via one of these penetrating bore 46 is connected to the linkage 16 serving as a compressed air supply line. The blind bore 42 is connected via radially directed channels 48 to an annular space 50, which is formed by a reduced-diameter section of the percussion piston 40 between the latter and the housing wall surrounding it. This annular space 50 is connected via longitudinal grooves 52 in the front area of the percussion piston 40 to the interior of the housing 32 lying in front of the percussion piston 40. The ram boring machine described so far and known per se works as follows: When compressed air is supplied via the linkage 16, the bore 46 and the control tube 44, the percussion piston 40 is accelerated forward (to the left in FIG. 3). Shortly before the percussion piston 40 with its end face 54 reaches the impact surface 56 on the head 36, the radial bores 48 come into contact with the front end of the control tube 44, so that compressed air through the radial bores 48, the annular space 50 and the longitudinal grooves 52 into the cavity can get in front of the percussion piston 40. The compressed air reaches the front end face 54 of the percussion piston at the moment of impact and pushes the percussion piston 40 back again. Before the percussion piston 40 would strike the closure piece 38, the compressed air, as shown in FIG. 3, can escape from the front part of the housing cavity via the longitudinal grooves 52, the annular space 50 and the radial bores 48 as well as an exhaust air bore 58 running parallel to the axis in the closure part 38 , which is connected to an exhaust hose 60. The compressed air inside the control tube 44 brakes the percussion piston softly in its rear position so that it does not strike the closure piece 38.

Nozzle openings 62 are formed on the head 36, each of which is connected to pressure fluid line 66 via channels 64 which run within the housing wall and the closure piece 38 and which are connected to the closure piece 38. Pressure channels are supplied via channels 64 and lines 66 from a pressure fluid source 68, which is shown schematically in FIG. 1, which emerges from the nozzle openings 62 with a sharp jet. The supply to the individual nozzles is controlled via control valves 70 which are schematically indicated in FIG. 3 and which are arranged in the pressure fluid source 68 in the present example. With these control valves 70, the amount and / or the pressure of the pressure fluid supplied to the individual nozzle openings 62 can be adjusted individually in order to achieve the above-described directional control of the earth drilling device 10.

Further nozzle openings 71 are provided in the cylindrical section 34 of the housing 32. The nozzles 71 are each — in relation to the longitudinal axis of the earth drilling device 10 — in alignment with the nozzles 62, as shown in FIG. 3. Through them, liquid can be pressed between the cylindrical section 34 and the surrounding earth, on the one hand to facilitate the sliding of the earth drilling device in the ground. On the other hand, by specifically controlling these lateral nozzles 71 together with the respective nozzle 62 on the head 36, the ground can be loosened over a longer distance, so that the change of direction is possible within a shorter distance.

Figures 4 to 7 show two known heads of earth drilling equipment, on which jet nozzles are now arranged according to the invention. The heads are shown individually, but can be made in one piece the cylindrical portion of the housing 32, as shown in Figure 3.

FIGS. 4 and 5 show a conical displacement head with longitudinal grooves 72, in which jet nozzles 74 are arranged, which, in contrast to the nozzle openings 62 in FIG. 3, direct the pressure fluid jet obliquely forward at a predetermined angle a (FIG. 6). As can be seen in FIG. 5, the grooves 72 and the nozzles 74 are distributed symmetrically about the axis of the head at equal angular distances.

Figure 7 shows a stepped head which has better shattering properties for use in hard and stony soil. This head also has longitudinal grooves 72, in which, as an example, two jet nozzles 74 are arranged one behind the other, the radiation angle of which can be selected to be the same or different, so as to increase the control options. In this case, the nozzles can be connected in a longitudinal groove 72 to a common or else to separate hydraulic fluid lines.

FIGS. 9 and 10 each show a nozzle body 74 which is designed in the form of a slotted screw which can be screwed into the respective nozzle opening 62 and through which a nozzle channel 75 runs. In the case of the nozzle body 74 according to FIG. 9, the nozzle channel 75 is axially directed, whereas in the embodiment according to FIG. 10 the nozzle channel forms an angle with the screw axis. The jet angle of the nozzles can be adjusted by entering nozzle bodies with differently designed nozzle channels. In the case of an obliquely directed nozzle channel, the jet direction can also be changed by rotating the nozzle body.

FIG. 8 shows a vibration damper, generally designated 76, which is inserted between the closure part 38 and the linkage 16 in order to prevent its being damaged by the ram impacts of the ram boring machine. The vibration damper comprises a cylindrical housing 78, which is screwed at one end into the closure part 38 and serves to guide a piston 80 connected to the linkage 16, a damping spring 82 being provided between the end surface of the housing 78 facing the closure part 38 and the piston 80 is arranged.

In the above description, a ram boring machine has been described as a particularly preferred exemplary embodiment. The control with the aid of nozzles arranged on the head of a ram boring machine and pressure fluid jets emerging through the nozzles can also be used with a static earth boring machine, as is shown schematically in FIG. This earth drilling machine is driven not by the ramming impacts of a percussion piston but by the feed pressure introduced via the linkage. Otherwise, however, the statements made regarding the ram boring machine described above also apply in the same way to such a static earth boring machine. Both types of devices have the advantage over the previously known solutions that the control of the nozzles for the purpose of changing the direction can take place during the advance of the device.

In both exemplary embodiments, a transmitter 84, shown schematically in FIG. 3, can be arranged in the head 36 of the earth drilling device, which enables a correct position determination of the earth drilling device.

Claims (18)

1. Method for the direction control of an earth drilling apparatus (10), which comprises a tubular casing (34) and a head (36) arranged coaxially thereto, in which before or during the advance of the earth drilling apparatus (10) hydraulic fluid is passed to the discharge nozzles (62, 74) constructed in the head (36) for deflecting the apparatus from its axial advance direction, characterized in that in the construction of the earth drilling apparatus as a ram drilling apparatus (10) the material positioned laterally alongside the head (36) of the apparatus (10) is loosened or removed by supplying hydraulic fluid only to the nozzle (62, 74) or nozzles (62, 74), whose jet is directed laterally of the head of the ram drilling apparatus (10) at least approximately in the desired deflection direction of said apparatus (10).
2. Method for the directional control of an earth drilling apparatus (10), which comprises a tubular casing (34) and a head (36) arranged coaxially thereto, in which before or during the advance of the earth drilling apparatus (10) hydraulic fluid is passed to the discharge nozzles (62, 74) constructed in the head (36) for deflecting the apparatus from its axial advance direction, characterized in that in the construction of the earth drilling apparatus as a ram drilling apparatus (10), the material positioned laterally alongside the head (36) of the apparatus (10) is loosened or removed, in that the pressure of the hydraulic fluid on the nozzle (62, 74) or nozzles (62, 74), whose jet is directed laterally of the head (36) of the apparatus (10) at least approximately in the desired deflection direction of the ram drilling apparatus (10), is higher than the pressure of the hydraulic fluid at the other nozzles (62, 74).
3. Method according to claim 1 or 2, characterized in that in the tubular casing (34) are located further discharge nozzles (71) which, considered in the longitudinal direction of the ram drilling apparatus, are in each case aligned with at least one discharge nozzle (62) of the head (36) and which are in each case supplied with hydraulic fluid in the same way as the discharge nozzles (62) of the head (36) in alignment therewith.
4. Method according to one of the claims 1 to 3, characterized in that the pressure of the hydraulic fluid at the nozzles (62, 74) discharging in the desired deflection direction is approximately 20 to 250 bar.
5. Method according to one of the claims 1 to 4, characterized in that the hydraulic fluid has thixotropic or lubricant characteristics.
6. Earth drilling apparatus for performing a method according to one of the claims 1 to 5 with a tubular casing (34), a head (36) arranged coaxially thereto and means (40, 16) for advancing the earth drilling apparatus (10), at least three nozzles (62, 74) being located in the head (36) of the earth drilling apparatus (10) and are connectable to a hydraulic fluid source (68) and are so laterally arranged rearwardly of the head tip that the direction of the jet passing laterally out of the particular nozzles (62, 74) laterally of the earth drilling apparatus (10) forms an angle (a) with the longitudinal axis of the apparatus (10) and in which the hydraulic fluid supply to each nozzle (62, 74) is individually controllable and in which the earth drilling apparatus is constructed as a dynamic ram drilling apparatus (10) and the hydraulic fluid supply is controllable with respect to the hydraulic fluid pressure or quantity.
7. Apparatus according to claim 6, characterized in that the jet angle of the nozzles (74) is adjustable.
8. Apparatus according to claim 6 or 7, characterized in that a plurality of nozzles (74) is successively arranged in the longitudinal direction of the ram drilling apparatus (10).
9. Apparatus according to one of the claims 6 to 8, characterized in that further nozzles (71) are placed in the tubular casing (34) and which, considered in the longitudinal direction of the ram drilling apparatus, are in each case aligned with at least one discharge nozzle (62, 74) of the head (36).
10. Apparatus according to one of the claims 6 to 9, characterized in that the nozzles (74) are positioned symmetrically with respect to the longitudinal axis of the ram drilling apparatus (10).
11. Apparatus according to one of the claims 6 to 10, characterized in that the head (36) of the ram drilling apparatus (10) is conically constructed and has grooves (72) distributed symmetrically with respect to the axis over the conical surface and in these are located the nozzles (74).
12. Apparatus according to one of the claims 6 to 10, characterized in that the head (36) of the ram drilling apparatus (10) has a stepped construction and has longitudinal grooves (72) symmetrically distributed with respect to the axis and in which are located the nozzles (74).
13. Apparatus according to one of the claims 6 to 12, characterized in that the nozzles (62) are connected to channels (64) running in axially parallel manner in the casing wall and whose head-remote ends are connected by flexible lines (66) to the hydraulic fluid source (68).
14. Apparatus according to one of the claims 6 to 13, characterized in that control valves (70) for controlling the hydraulic fluid supply to the individual nozzles (62, 74) are located in the ram drilling apparatus (10).
15. Apparatus according to one of the claims 6 to 14, characterized in that a transmitter for determining the position of the ram drilling apparatus (10) is installed in the head (36) of said apparatus (10).
16. Apparatus according to one of the claims 6 to 15, characterized in that the ram drilling apparatus (10) is connected to a thrust linkage (16) by means of which an advance force can be exerted on said apparatus (10).
17. Apparatus according to claim 16, characterized in that a vibration damper (76) is located between the ram drilling apparatus (10) and the linkage (16).
18. Apparatus according to one of the claims 6 to 17, characterized in that the casing (34) of the ram drilling apparatus is connected to a water-tight exhaust air duct (60), which removes the compressed air necessary for driving a percussion piston (40) of the ram drilling apparatus.

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