| 摘要 |
The invention features an excavating device for excavating a hole in a geological formation, which excavating device includes: a body rotatable inside the hole along a rotation axis; a nozzle arranged on the body to jet a stream of an abrasive fluid onto a surface in the geological formation in order to generate the hole, wherein the stream has at least an radial velocity component and one parallel to the rotation axis. The excavating device further has a distance holder arranged on the body to ensure a predefined distance between the nozzle outlet and the surface; wherein the distance holder has a trumpet shaped inner surface section facing the geological formation, which trumpet shaped inner surface section is provided with an opening for allowing the stream to pass through. The opening in the trumpet shaped inner surface section is defined by a recess that is formed in the inner surface of the wall of the distance holder, whereby the nozzle is arranged to discharge in the recess. The invention also features a distance holder such as described above.
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