| 摘要 |
<p>A pressure control system comprising a fluid supply line 4, configured to carry pressurised fluid to the apparatus, such as a downhole hammer 7, a fluid return line 8 configured to carry exhaust fluid from the hydraulic percussion apparatus, a pressure control means 9 configured to drive the exhaust fluid in the fluid return line, when a backpressure at an outlet (12) of the apparatus exceeds a threshold. The pressure control means may comprise a means for extracting energy from the pressurised fluid supply line and imparting it to the fluid return line and may comprise a motorised pump 11 arrangement or a means for diverting a portion of the fluid from the fluid supply line 4 to the return line 8.</p> |
