| 摘要 |
A distance holder for connection to, and rotation with, a drill string in an earth formation drilling device arranged to supply a jet of abrasive fluid for the purpose of providing a borehole by removing earth formation material through abrasion, comprises a chamber that is essentially rotational symmetric and which faces the earth formation material, and a jet nozzle arranged for discharging a jet of the abrasive fluid in the chamber. The chamber comprises a deflector positioned in the path of the fluid jet discharged from the jet nozzle.
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