WO2008071666A1 - Method for breaking up hard rock, and a drilling apparatus - Google Patents

Abstract

In a method for breaking up hard rock and a corresponding apparatus, a drill head has an end face which can be arranged facing a drift face. At least two electrodes (10, 11) are arranged on the end face of the drill head. The drilling apparatus has voltage means (3, 4, 5, 6, 7, 8, 9) via which a voltage can be formed between the electrodes (10, 11), at a controlled frequency. During operation, the drilling apparatus is arranged adjacent to the drift face of the hard rock to be broken up, and the frequency-controlled voltage is applied between the electrodes (10, 11). The frequency-controlled voltage results in streamer discharges between the electrodes (10, 11) because of their different electrical potentials, which pass through the hard rock, resulting in it being separated and broken up along the joint boundaries in the area in which the streamer discharges act. In this case, the electrodes (10, 11) make no contact, or only resting contact, on the drift face, without any significant force being transmitted to the drift face, so that any wear on the electrodes (10, 11) is minor.

Description

 Process for breaking down hard rock and drilling equipment

Technical area

The present invention relates to a method for the degradation of hard rock according to the independent method claim and to a drilling apparatus according to the independent device claim.

Drilling devices with a drill head, which has a face facing an approachable end face can be used for the degradation of hard rock in tunneling or deep wells.

State of the art

For mining of hard rock in tunnels to be drilled (essentially horizontal holes) and deep holes (essentially vertical holes) mining tools in the form of rollers or round shank bits are nowadays arranged on a rotating cutting wheel of a drill head. By generating a contact pressure of tunneling machine or drill head on the tools on the working face pressure and tensile strength limits are exceeded in the rock and thereby mechanically dissolved rock material. The dissolved rock material is then broken mechanically to recoverable size in a crusher chamber and transported away in the slurry, belt or cart conveyor. In deep drilling technology, the material is typically dissolved analogously and transported away in the pump or air lifting process.

Due to the presence of certain constituents, such as minerals, in the degraded hard rock and adhesion wear of the mining tools takes place, so that they must be replaced periodically depending on Bohrfortschritt and hard rock properties, which can cause considerable costs. In tunneling, this requires access to the cutting wheel, which is permitted only from diameters of about 1 '200 mm. In deep drilling, the drill head and its associated pipe string must be removed and reinstalled to replace the mining tools. In both cases, the actual hard rock mining be adjusted in the meantime, which reduces the total degradation capacity of the drilling device.

The invention has for its object a method and a

Drilling device for the extraction of hard rock and to provide a method for the degradation of hard rock, which allow an efficient and economical degradation of hard rock.

Presentation of the invention

This object is achieved according to the invention by a method for the degradation of hard rock, as characterized by the features of the independent method claim. Advantageous variants of the inventive method are the subject of the dependent method claims.

In particular, the method according to the invention comprises the following steps:

Arranging at least two electrodes on a working face; Generating streamer discharges through the hard stone of the working face by means of frequency-controlled build-up of a voltage between the electrodes.

Due to the frequency-controlled voltage between the electrons can be formed due to their different electrical potentials switched streamer discharges, which are due to the short-term higher dielectric strength of a dielectric, which is preferably between the electrodes, are generated by the degraded hard rock. As described above, the hard rock can thus be degraded in an advantageous manner according to the invention.

Preferably, a rinsing liquid is introduced between the electrodes, with which degraded hard rock is removed.

Particularly preferred while a rinsing liquid is used, which has an at least temporarily higher electrical breakdown strength than the degraded hard rock.

Furthermore, a turbine is preferably operated by means of the rinsing liquid, so that a generator is driven by the turbine and generates an AC voltage. This AC voltage is then over a rectifier is converted into DC voltage and by means of a high voltage generator, a high voltage is generated from the DC voltage, which is frequency-controlled transmitted to the electrodes.

Another aspect of the invention relates to a drilling apparatus as characterized by the features of the independent apparatus claim. Advantageous embodiments of the inventive drilling device emerge from the features of the dependent device claims.

In particular, at least two electrodes are arranged on the front side of the drill head of the drilling device and the drilling device has tensioning means over which frequency-controlled voltage between the electrodes is buildable, in such a way that a streamer discharge through the hard rock of the working face can be generated. In operation, the drilling device according to the invention is arranged at the face of the hard rock to be degraded and the frequency-controlled voltage is built up between the electrodes. The working face here means the point of the hard rock where the hard rock is to be mined or is being mined. Due to the frequency-controlled voltage, streamer discharges are formed between the electrons due to their different electrical potentials, these streamer discharges being generated by the hard rock to be degraded because of the short-term higher electrical breakdown strength of a preferably present dielectric which is located between the electrodes. As a result, it is dissolved and degraded in the effective range of the streamer discharges along the structural boundaries. Thus, the hard rock is not solved conventionally with appropriate mining tools mechanically by exceeding strength limits, but by quasi non-contact degradation by means of electrical discharges in the hard rock. The electrodes have no or only adjacent contact with the working face without significant force transmission to the working face, so that the wear on the electrodes is low. Thus, the wear on the Dismantling tools of the drilling apparatus and accordingly minimized the downtime of the drilling device, so that an economic and efficient degradation of the hard rock is possible.

Preferably, the electrodes comprise a central electrode disposed substantially centrally on the end face and a plurality of caliber electrodes arranged peripherally on the end face. By means of such an arrangement of the electrodes, in particular with an annular arrangement of the caliber electrodes around the center electrodes around, an advantageous mining cross-section can be produced which is, for example, large enough that an overcut can be produced between the drill head and the rock surrounding the drill head.

Advantageously, the drilling device comprises rinsing agent and the drill head has a jacket tube, wherein by means of the rinsing agent, a rinsing liquid through the jacket tube through to the front side and between the electrodes is conveyed. The rinsing liquid can be used on the one hand as a dielectric between the electrodes, which means that it serves as an insulating medium around the electrodes around and ensuring the Streamerentladungen through the degraded hard rock through. On the other hand, the rinsing liquid is also a conveying medium with which the mined hard rock can be transported out of the excavation channel.

In an advantageous embodiment, the drill head against its end facing the end toward a high voltage region, towards its end facing away from the end of a low-voltage range and between the high-voltage region and the low-voltage region a medium voltage range. In the low-voltage range, a turbine which can be operated by means of the flushing liquid and a generator which can be driven by the turbine are arranged. In the medium voltage range while a rectifier is arranged, by means of which AC voltage from the generator is converted into DC voltage. In the high voltage range, a high voltage generator with capacitors is arranged, by means of which a frequency-controlled high voltage which can be transmitted to the electrodes can be generated. About such an arrangement, the Tension means can be arranged in the drill head itself and in particular streamer discharges can be generated by a arranged in the drill head high-voltage pulse generator, the frequency-controlled passes the voltages to the electrodes.

Preferably, the high voltage generator is stored isolated. In such an isolated environment unwanted discharges between the capacitors can be easily avoided.

Advantageously, the drill head on a grounding device, so that a safe stable operation of the drill head can be ensured, and so that in a simple manner, a sufficient potential difference between the electrodes can be provided.

Brief description of the drawings

Further advantageous embodiments of the invention will become apparent from the following description of an embodiment of the invention with the aid of the schematic drawings. Show it:

Fig. 1 is a longitudinal sectional view of the drill head of an embodiment of the inventive drilling device, which is suitable here for example for deep drilling; and

2 is a view of a working face forth on the electrodes of the drilling apparatus of Fig. 1.

Way (s) for carrying out the invention

Certain terms are used in the following description for convenience and are not intended to be limiting. The words "bottom" and "top" designate directions in the drawing to which reference is made. The terms "inward" and "outward" refer to directions toward or away from the geometric center of the drilling apparatus and designated parts thereof. The terminology includes the words expressly mentioned above, derivatives thereof, and words of similar meaning.

In Fig. 1, a drill head of a drilling device according to the invention is shown. It has a substantially hollow cylindrical jacket tube 1 (shield) and accommodated therein tension means for generating a streamer discharges. The drill head is suspended and guided by a drill pipe 2, which is suspended successively extended on a derrick for days. Through the drill pipe, a rinsing liquid, which is simultaneously a dielectric in the exemplary embodiment shown in FIG. 1, is supplied from the surface to the drill head.

In an upper low voltage range of the drill head, the flushing fluid is passed through hydrostatic pressure through the arranged in the low voltage region of the drill head turbine 3 (Moineau), which acts as a downhole motor and Bohrkopfantrieb. The turbine 3 drives by rotation a generator 4, which supplies an input AC voltage.

From the generator, the input AC voltage is forwarded via a medium-voltage transformer 5 in a medium voltage range of the drill head. In the medium-voltage range, the input AC voltage is converted via a rectifier 6 into a DC voltage and further led into a lower high-voltage region and a Bohrkopfspitze. Resistors reduce the corresponding short-circuit current to a charging unit if an error occurs. A grounding of the entire drill head via a jacket outer surface via sliding contacts 7 in the soil.

In the high voltage range of the drill head high voltage via a high voltage generator 8 according to the Marx principle, in which the capacitors 9 are connected in parallel and discharged in series, discharged generated. In order to avoid premature unwanted discharge between the capacitors 9 instead of electrodes designed as a center electrode 10 and a caliber electrode 11, the high voltage generator is mounted in an isolated manner.

From the high voltage generator, the high voltage is directly controlled frequency controlled in the individual electrodes when reaching a threshold voltage. Due to the different dielectric strength of the dielectric and the hard rock, the streamer discharge takes place between the center electrode 10 and the caliber electrodes 11 through the hard rock. The caliber electrodes 11 are the drill head designed outwardly outstanding and as shown in Fig. 2 best seen peripherally disposed on the front side of the drill head. As a result of this arrangement of the caliber electrodes 11, an excavation cross-section which is larger than that of the jacket tube 1 and an overcut between the jacket tube and the surrounding hard rock is produced. The functioning as a rinsing liquid dielectric, which by the

Bohrkopfzentrum is passed to the face, takes the detached hard rock and promotes this with the help of injected air after the air lifting process in the overcut between casing 1 and surrounding hard rock to day.

Claims

claims 1. A process for the degradation of hard rock, comprising the following steps: Arranging at least two electrodes (10, 11) on a working face; Generating streamer discharges through the hard stone of the working face by means of frequency-controlled build-up of a voltage between the electrodes (10, 11) arranged at the working face. 2. The method of claim 1, wherein a rinsing liquid between the electrodes (10, 11) is introduced, with which degraded hard rock is removed. 3. The method of claim 2, wherein a rinsing liquid is used, which has an at least temporarily higher electrical breakdown strength than the degraded hard rock. 4. The method according to any one of claims 2 or 3, wherein a turbine (3) is operated by means of the rinsing liquid, so that a generator (4) is driven by the turbine (3) and generates an AC voltage, in which this AC voltage via a Rectifier (6) is converted into a DC voltage, and in which by means of a high voltage generator (8) from the DC voltage, a high voltage is generated, which is frequency-controlled to the electrodes (10, 11) is transmitted. 5. Drilling device for the degradation of hard rock, comprising a drill head, the one facing a working face, which contains the hard stone to be degraded facing arranged end face, characterized in that at the end face of the drill head at least two electrodes (10, 11) are arranged and that the drilling device has tensioning means (3, 4, 5, 6, 7, 8, 9) via which frequency-controlled voltage can be built up between the electrodes (10, 11) such that a streamer discharge can be generated through the hard rock of the working face. 6. Drilling device according to claim 5, wherein the electrodes (10, 11) comprise a central electrode arranged substantially centrally on the end face (10) and a plurality of peripherally arranged on the front side caliber electrodes (11). 7. Drilling device according to one of claims 5 or 6, which comprises flushing means and in which the drill head has a jacket tube (1), wherein by means of the rinsing agent a rinsing liquid through the jacket tube (1) through to the front side and between the electrodes (10, 11 ) is eligible. 8. Drilling device according to claim 7, wherein the drill head towards its end facing the end of a high voltage region, facing away from the front end towards a low voltage region and between the high voltage region and the low voltage region has a medium voltage range, wherein in the low voltage region, a turbine (3), which is operable by means of the rinsing liquid, and a generator (4), which is drivable by the turbine (3) are arranged, wherein in the medium voltage range, a rectifier (6) is arranged, by means of which AC voltage from the generator (4) convertible into DC voltage is, and wherein in the high voltage region, a high voltage generator (8) with capacitors (9) is arranged, by means of which a to the electrodes (10, 11) transferable frequency-controlled high voltage can be generated. 9. Drilling apparatus according to claim 8, wherein the high voltage generator (8) is mounted isolated. 10. Drilling device according to one of claims 5 to 9, wherein the drill head has a grounding device (7).