| 摘要 |
<p>A distance holder (1) 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 (4) by removing earth formation material through abrasion, comprises a housing with a chamber (13) which is essentially rotational symmetric and which is to face the earth formation material, and a jet nozzle (10) which arranged for discharging a jet of the abrasive fluid in said chamber, said housing comprising at least one slot (18) for allowing the abrasive fluid to leave the chamber. The slot is continued over the housing outer surface so as to counteract rolling motions of the particles which are comprised in the abrasive fluid.</p> |
