EP0131771B1 - Drilling device, especially for underground mining - Google Patents

Abstract

The invention relates to a drilling equipment whose annular bit (4) for cutting the rock located in the deepest point of the drill hole is provided with high-pressure water-jet nozzles and is connected via a flexible high-pressure hose pipe (13) with a high-pressure pump. In order to be able to drill with the aid of such a drilling equipment small-diameter drill holes of high directional stability, the invention proposes that the high-pressure hose pipe (13) be constructed to be rigid under torsion, non-rotatably connected to the annular bit (4) and the turning drive (24, 25) of the drilling machine (8) and to be journaled in a non-rotatable jacket tube (15) elastically deflectable from the extension position, said jacket tube being rigid in radial direction and guided in the area of the drill hole mouth in a deflecting device (7) and displaceable together with the high-pressure hose pipe (13) in its longitudinal direction.

Description

The invention relates to a drilling device, in particular for use in underground mining operations, the drill bit of which is arranged deepest in the borehole for cutting the rock and has high-pressure water jet nozzles and is connected to a high-pressure pump by a flexible high-pressure hose line.

Such a drilling device known from the prior art (DE-A-3 141 856) has the particular advantage that no rigid boring bars are required. The flexible high-pressure hose line allows holes of any length to be produced in one direction from narrow spaces in a mine, the length of the holes being limited only by the length of the high-pressure hose.

The previously known drilling device of the type mentioned, however, has the disadvantage that the boreholes produced with it must have a very large caliber and can only be held in a directionally stable manner with difficulty. The relatively large caliber is necessary because in the known drilling device the rotary drive and the feed drive are arranged deepest in the borehole and require appropriate space. Due to the relatively large caliber, the previously known drilling device can only be used economically in easily drilled rock, for example for drilling in coal seams for the production of impregnation holes, but not in hard rock for the production of small-caliber rock anchor holes or blast holes. The directional stability is poor because the high-pressure hose line cannot provide the drill bit with any guidance.

According to the prior art (DE-A-3 029 963), a drilling device is also known, the small-caliber drill bit for cutting the rock is provided with high-pressure water jet nozzles. There, however, hollow, rotatably driven rigid boring bars are used for supplying the high-pressure water, so that this device has no significant advantages over conventional drilling devices with a rigid drill pipe.

Finally, according to the prior art (US-A-4 057 115 and DE-A-3 043 512), drilling devices are known which use a flexible shaft as the drill pipe, which stiffens when a torque is applied to form a rigid rod. For this purpose, the flexible shaft consists of a flexible inner element and an outer helical spring element, which is also flexible and, when a correspondingly strong torque is transmitted, reduces its diameter in such a way that it presses onto the flexible inner element from the outside and stiffens with it Unity forms. In this known drilling device, this flexible shaft is grasped immediately below the mouth of the borehole by the rotary and feed drive arranged there, so that only the section of the flexible shaft located in the borehole is rigid, while the section of the flexible shaft behind the rotating and feed device is flexible remains. This drilling device therefore allows the flexible boron rod to be angled in any direction.

However, the drilling devices discussed last have not proven themselves in practice because the rigidity of the rigid, flexible shaft is not sufficient to transmit the thrust forces and torques required for the drilling process. In addition, the wear on the borehole wall is extremely high due to the friction of the not quite rigid flexible shaft. Finally, the directional stability is also poor here because of the strong shear forces to be transmitted and the associated deflections of the stiffened section of the flexible shaft.

It is an object of the invention to further develop the drilling device of the type mentioned at the outset in such a way that it is suitable for angled drilling of directionally stable small-bore holes, for example for producing anchor holes or blast holes.

To achieve this object, the invention proposes, starting from a drilling device of the type mentioned at the outset, that the high-pressure hose line is designed to be torsionally rigid, is connected in a rotationally fixed manner to the drill bit and the rotary drive of the drilling machine, and is mounted in a non-rotatable jacket tube which can be deflected elastically from the extended position, which is rigid in the radial direction, is guided in the region of the mouth of the borehole in a deflection device and can be displaced in its longitudinal direction together with the high-pressure hose line.

The invention is based on the knowledge that when drilling with high-pressure water jet nozzles, relatively low feed forces and torques have to be transmitted from the boron rod. The torque to be transmitted only needs to overcome the friction resulting from the rotation of the nozzle drill bit and the high-pressure hose. The feed force only has to compensate for the weight of the nozzle drill bit, the high pressure hose and the cladding tube as well as the recoil force of the nozzles. For the actual drilling process, however, neither torques nor feed forces need to be transmitted. For this reason, a torsionally rigid high-pressure hose line is completely sufficient for the transmission of the relatively weak torque. A sufficiently rigid cladding tube that can be deflected elastically from the extended position is also sufficient for the transmission of the relatively low feed forces. Because the cladding tube cannot be rotated, it can be guided in a particularly simple manner in a deflection device in the region of the borehole mouth and, due to its elastic restoring forces in the borehole, forms a sufficiently precise guide for the drill bit, so that a directionally stable drilling is ensured.

With the drilling device according to the invention, it is possible, for example, to drill anchor holes of any length into the roof layers from a narrow longwall space, the length of which is a multiple of the seam thickness speaks. In mechanical stretching, where the extraction machine takes up the major part of the cross-section, anchor drill holes of any length can be produced with the drilling device according to the invention, the direction of which runs at an angle to the longitudinal direction of the line. In the same way, it is possible to produce angled boreholes angled from the edge of the route on the face.

A preferred embodiment of the drilling device according to the invention provides that the cladding tube consists of a helical spring wound from spring steel wire with adjoining screw threads. Such a cladding tube is cheap and easy to manufacture, has relatively great rigidity in the extended position and can nevertheless be angled as desired in the region of the deflection device without changing its diameter.

It is further provided that the high-pressure hose is surrounded by a wear jacket, in particular in the form of a helical spring that is tightly wound around the high-pressure hose. This coil spring protects the high-pressure hose from wear and is also suitable to a certain extent to support the torsional rigidity of the high-pressure hose.

In order to keep the friction between the cladding tube and the high-pressure hose as low as possible, the cladding tube is lined liquid-tight on the inner wall and / or the outer wall and the annular space between the cladding tube and the high-pressure hose is filled with grease.

In order to give the cladding tube exact guidance over a sufficiently large length in the deflection area, the deflection device has a deflection roller and a link chain-like, angularly adjustable guide equipped with guide rollers, which guides the cladding tube behind the deflection roller.

For the purpose of starting a new borehole, the deflection device has a tapping guide, which can be shifted and locked to change the deflection angle on a guide curve and is connected to the link chain-like guide, the guide curve being designed such that the link chain-like guide is always tensioned and one forms the optimum bending radius for the cladding tube. This deflection device allows the cladding tube and the high-pressure hose guided therein, to the extreme end of which the nozzle drill bit is attached, to be brought into the correct position during drilling and to be pushed in the correct angular position during the entire drilling process.

In order to prevent the tapping guide and the deflection device connected to it from being contaminated by drilling mud emerging from the borehole, these parts are protected by a sleeve arranged above the tapping device.

In order to ensure a straight course of the cladding tube outside the borehole, the deflection device contains drive rollers which keep the cladding tube stretched in the longitudinal direction between the deflection device and the drilling machine.

The drilling machine is expediently mounted on a drill carriage and can be moved in the longitudinal direction of the drill carriage by means of a controllable feed drive by advancing the cladding tube and the high-pressure hose rotatably mounted therein. Since the longitudinal axis of the drill carriage can run at any angle to the longitudinal axis of the borehole, such a drill carriage can easily be set up, for example, on the faceplate or in the edge region of a line.

In order to introduce the high pressure water into the high pressure hose, a rotatable pressurized water supply is expediently arranged at the beginning of the high pressure hose. In order to keep this pressurized water feed free from axially directed pressure forces, a hollow shaft is provided which is connected to the high-pressure hose and is driven by the rotary drive of the drilling machine, which is rotatably mounted in a pressurized water pressure housing, is provided in the center with openings for the pressurized water inlet and on both sides through the center symmetrically arranged sealing sleeves is sealed against the pressure housing.

In order to keep the sealing sleeves tight in spite of the very high water pressures, the invention further provides that the sealing sleeves are acted upon on the rear side by a second pressure medium of high viscosity, the pressure of which is slightly higher than that of the pressurized water. This highly viscous second pressure medium prevents high-pressure water from passing through the sealing sleeves, but due to its high viscosity only reaches the pressure water in very small quantities.

In order to automatically keep the pressure in the second high-viscosity pressure medium always in the correct ratio to the instantaneous pressure of the pressure water, a pressure intensifier is switched on between the high-pressure water and the high viscosity medium, the transmission ratio of which is between 1: 1.1 and 1: 2.

Finally, the feed speeds of the drive rollers of the deflection device, the speed of rotation of the drilling machine and the operating pressure of the high-pressure pump are advantageously regulated in such a way that an optimal drilling progress results depending on the hardness of the rock to be drilled. Such a control device enables optimal drilling results, even if the hardness of the rock to be drilled changes.

The feed speed of the feed drive of the drill and the feed speed of the drive rollers of the deflection device are expediently coordinated with one another in such a way that the cladding tube between the drill and the deflection device is always kept tight. On the one hand, this prevents the feed drive of the drive rollers from pulling the heavy drilling machine. On the other hand, it is avoided that the cladding tube between the drill and the deflection device is bent laterally.

• Fig. 1 eine Bohreinrichtung gemäss der Erfindung schematisch im Aufbau;
• Fig. 2 in perspektivischer Darstellung den Aufbau der Hochdruckschlauchleitung und des Hüllrohres;
• Fig. 3 eine Prinzipskizze der gesamten maschinellen Einrichtung;
• Fig. 4 den Aufbau des Ablenksystems im einzelnen;
• Fig. 5 die für die Bohreinrichtung gemäss der Erfindung unbedingt erforderliche Druckwassereinspeisung schematisch im Längsschnitt.

An embodiment of the invention is explained below with reference to the drawing. Show it:

• 1 schematically shows a drilling device according to the invention in construction;
• Figure 2 is a perspective view of the structure of the high pressure hose and the cladding tube.
• 3 shows a schematic diagram of the entire mechanical device;
• 4 shows the structure of the deflection system in detail;
• Fig. 5 schematically in longitudinal section the pressurized water feed absolutely necessary for the drilling device according to the invention.

In Fig. 1 it can be seen that the device for angled drilling is arranged on a normal drill carriage 1 with a pivotable boom 2 and a drill carriage 3. Instead of the drill carriage, a different type of manipulator can also accommodate the drill carriage 3, for example a device suitable for mechanized tunneling or the production of anchor drill holes in extraction struts.

A nozzle drill bit 4 is arranged at the free end of a pressure supply system, which is designated in its entirety with the reference number 5 and can be deflected by a deflection device 7 directly in front of the borehole mouth 6. On the drill carriage 3, a drill 8 can be moved in the longitudinal direction of the drill carriage. The high-pressure water is fed to the drilling machine 8 from a high-pressure pump 10 via a connection high-pressure hose line 9. Rotating and swiveling cylinders 11 and a locking device 12 for fixing the drill carriage 3 complete the device. During the drilling process, the drilling machine 8 moves on the drill carriage 3 towards the borehole, while the deflection of the pressure supply system 5 takes place in the deflection device 7. The length of the angled borehole is not determined by the narrowness of the pit space, but only by the movement stroke of the drilling machine 8 on the drilling mount 3 and the total length of the pressure supply system 5.

The pressure supply system 5 shown in Fig. 2 consists of a torsionally rigid high-pressure hose 13, the clear cross section of which is dimensioned such that the amount of water required for the nozzle core bit 4 can be passed through without too great a pressure loss, and the bursting pressure of which is so high that there is sufficient security compared to the maximum operating pressure. In the exemplary embodiment of the invention shown here, a helical spring 14 is firmly wound around this high-pressure hose line 13, which serves as wear protection and additionally increases the torsional rigidity. The high-pressure hose line 13 and the helical spring 14 are arranged in a cladding tube 15 with a sufficiently large amount of play, which is also designed as a tightly wound helical spring with adjoining screw threads. The annular space 16 between the helical spring 14 and the cladding tube 15 is filled with lubricant, preferably with grease, in order to reduce the mutual friction when the high-pressure hose line 13 is rotated in the cladding tube 15 arranged in a rotationally fixed manner. For this purpose, the inner wall of the casing tube 15, which is designed as a helical spring, is of course formed with a corresponding liquid-tight covering. The design of the cladding tube 15 as a helical spring with adjoining screw threads means that the cladding tube is relatively stable in the extended position and can nevertheless be deflected by appropriate deflecting forces.

Fig. 3 shows the basic structure and operation of the device for angled high pressure water drilling. In front of the borehole there is a tapping guide 17, which gives the cladding tube 15 and the high-pressure hose line arranged therein and carrying the nozzle drill bit 4 the required exact guidance at the desired angle during tapping. The tapping guide 17 has a bore 18 which also leads the cladding tube 15 in the desired direction during the normal drilling process. The tapping guide is covered by a sleeve 19 which ensures that the drilling water and cuttings emerging from the borehole mouth 6 do not contaminate the tapping guide 17 and the other mechanical devices or stick after drying out. The tapping guide 17 can be displaced and locked on a guide curve 20 of the deflection device 7 by movement mechanisms which are not shown in detail. A deflection roller 21 and a link chain-like guide 22, whose radius of curvature and deflection angle can be adjusted with the tapping guide 17, ensure the actual deflection, with all roller raceways being designed in such a way that they optimally enclose the cladding tube 15.

The drilling machine 8 can be moved on the drill carriage 3 by means of a feed drive 23, the feed drive being a hydraulic, electric or compressed air motor with a controllable rotational speed in order to generate a variable feed speed which automatically adapts to the needs of the drilling process. Another motor 24, which is also controllable, generates the rotary movement necessary for drilling via a countershaft 25, the high-pressure water being fed into the high-pressure hose line 13 from the high-pressure pump 10 via the rotatable pressurized water feed 26.

Drive rollers 27, which are also driven by a control drive (not shown) and exert an adjustable, low tensile force on the cladding tube 15, are arranged in the deflection device 7. The control motors for the drive rollers 27 as well as the propulsion drive 23 and the motor 24 can be linked to one another by a control system, measured values relating to the progress of the drilling being entered into the control system and automatically ensuring an optimal interaction of the drives and thus an optimal drilling process via its logic circuit. The water pressure of the high pressure pump 10 can also be influenced by this control mechanism.

4 shows the most important details of the deflection device 7. A deflection roller with a large diameter, the shape of which is adapted to the outer circumference of the cladding tube 15, and Infeed rollers at the inlet 28 and outlet rollers at the outlet 29 each ensure that the cladding tube 15 runs in and out correctly interconnected bearing elements 36 are arranged. As already mentioned, the guide 22 constructed in the manner of a link chain is connected to the tapping guide 17 in such a way that the tapping guide 17 and the link chain-like guide 22 simultaneously move with one another when the articulation angle changes.

5 shows the essential parts of the pressurized water feed 26. This pressurized water feed 26 has a hollow shaft 38 which is rotatably mounted in a pressure housing 39 and has openings 37 in the center for the passage of the high pressure water and a connection 40 at one end for the connection of the high pressure hose line 13 having. The shaft is driven at its opposite end 41 by the motor 24 shown in FIG. 3 and the countershaft 25. To create an axial balance of forces, the sealing elements for the hollow shaft 38 are constructed symmetrically. The main sealing takes place on the two sealing sleeves 42. However, since radial seals do not guarantee a perfect and absolute seal in the long run at very high water pressures, the sealing sleeves 42 are pressurized from their rear side via chambers 43 with a slightly higher pressure than the one to be sealed with a highly viscous second pressure medium . A pressure intensifier 44, which is pressurized with the high-pressure water on its full piston surface 45 and with the highly viscous second pressure medium on its annular surface 46, ensures that the sealing sleeves 42 are each subjected to a slightly higher pressure than the operating pressure on their rear side, thereby providing an absolute seal of the high pressure water is achieved. Two further sealing sleeves 47 seal the highly viscous medium. Because of the considerably higher viscosity compared to the high pressure water and the lubricity of the second pressure medium, there are no sealing problems at this sealing point. The sealing sleeves 48 only serve to avoid pressure losses of the highly viscous medium and the ingress of dust.

Claims (15)

1. Drilling device, particularly for use in underground mining operations, and of which the drill head (4) disposed in the bottom of the drill hole has high pressure water jets for cutting the rock, communicating by a flexible high pressure hose (13) with a high pressure pump (10), characterised in that the high pressure hose (13) is of torsion-resistant construction, is rotationally rigidly connected to the crown bore and the rotary drive (24, 25) of the drilling engine (8) and is mounted in a non-rotatable casing tube (15) which is elastically deflectib(e from the extended position and which is of rigid construction in a radial direction, is guided in the region of the drill hole mouth (6) in a diverting device (7) and is displaceable in its longitudinal direction together with the high pressure hose (13).

2. Drilling device according to Claim 1, characterised in that the casing tube (15) consists of a coiled spring wound from spring steel wire and having adjacently disposed coils.

3. Drilling device according to Claims 1 and 2, characterised in that the high pressure tubing (13) is enclosed by a wearing sheath, particularly in the form of a coiled spring (14) wound closely around the high pressure tubing (13).

4. Drilling device according to Claims 1 to 3, characterised in that the casing tube (15) is clad in fluid tube fashion on the inner wall and/or the outer wall while the annular space (16) between the casing tube (15) and the high pressure tube (13) is filled with grease.

5. Drilling device according to one or more of Claims 1 to 4, characterised in that the deflecting device (7) comprises a deflecting roller (21) and an angularly adjustable guide (22) provided with guide rollers (31 to 34) of flat link chain construction.

6. Drilling device according to Claim 5, characterised in that the deflecting device (7) comprises a drilling guide (17) which, for varying the angle of deflection, is adjustable and lockable on a guide curve (20) and is connected to the chain-type guide (22), the guide curve (20) being so constructed thatthe chain-type guide (22) is always tensioned and constitutes an optimum bending radius.

7. Drilling device according to one or more of Claims 1 to 6, characterised in that the deflecting device (7) is safeguarded against dirt emanating from the drill hole by a sleeve (19) located over the drilling guide (17).

8. Drilling device according to Claims 1 to 7, characterised in that the deflecting device (7) comprises drive rollers (27) which maintain the casing tube (15) between the deflecting device (7) and the drilling engine (8) tension in a longitudinal direction.

9. Drilling device according to Claims 1 to 8, characterised in that the drilling engine (8) is mounted on a boom (3) and can be moved by a regulable feed drive (23) with an advance of casing tube (15) and of the high pressure tubing (13) rotatably mounted therein in the longitudinal direction of the boom (3).

10. Drilling device according to one or more of Claims 1 to 9, characterised in that a rotatable pressurised water feed (26) is located at the start of the high pressure tubing (13).

11. Drilling device according to Claim 10, characterised in that the pressurised water feed (26) comprises, connected to the high pressure tubing (13) and rotatingly driven by the rotary drive (24, 25) of the drilling engine (8) a hollow shaft (38) which is rotatably mounted in a pressure housing (39) to which water can be applied under pressure and which is centrally provided with apertures (37) for the inlet of water under pressure being sealed on both sides of the centre and in respect of the pressure housing (39) by symmetrically disposed sealing sleeves (42).

12. Drilling device according to Claim 11, characterised in that the sealing sleeves (42) are on their back subject to the action of a high viscosity second pressure medium, the pressure of which is slightly higher than that of the pressurised water.

13. Drilling device according to Claim 12, characterised in that a pressure translator (44) is located between the high pressure water and the high viscosity medium.

14._. Drilling device according to one or more of Claims 1 to 13, characterised in that the rate of feed of the drive rollers (27) of the deflecting device (7), the rotary speed of the drilling engine (8) and the operating pressure of the high pressure pump (10) are so regulated that an optimum drilling rate is assured as a function of the hardness of the rock through which it is intended to drill.

14. Drilling device according to Claim 14, characterised in that the rate of feed of the feed drive (23) of the drilling engine (8) and the rate of feed of the drive rollers (27) of the deflecting device (7) are so attuned to one another that the casing tube (15) is constantly maintained taut between the drilling engine (8) and the deflecting device (7).

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