Filter drill rod adapted for cleaning

摘要

The present invention relates to a filter drill rod 3 comprising first 11 and second 12 fluid flow channels, with a filter 17 disposed within said first channel, wherein pressure fluid can flow in either one of said channels and return fluids flows in the opposite channel, for connection to a hydraulic down-the-hole hammer 1, means 2 to selectively place first and second channels in fluid communication with one another and a filter cleaning valve component containing a moveable member 13.