| 摘要 |
<p>A drill stem (2) is screwed at its lower end into a guide pipe (3) which guides an impulse pipe (7) slidingly in the axial direction. A valve seat sleeve (10) screwed on to the lower end of the impulse pipe (7) contains a valve body (12) of an impulse valve (13) with a spring (15). A drilling tool (16) for drilling holes (1) is attached to the lower end of the valve seat sleeve (10). The parts (7, 10, 12, 15, 16) which move axially with respect to the drill stem (2) are raised by a spring (18) resting on a supporting ring (17) of the guide pipe (3), with the upper orifice (8) of the impulse pipe (7) against the lower orifice (5) of the drill stem (2). The oscillating lifting force is generated by means of ''water hammering'' in the long, spring-loaded impulse pipe (7) by the impulse valve (13) controlling the purging current (21). Unfiltered purging water can be used as the energy carrier in this system, which dispenses with the need for fitting and sliding seals.</p> |
