Back Reaming Subs For Reverse Circulation Hammers

Back Reamer (Backreamer) adapter prevents premature wear and tear of the Inner Tube in the dual-tube RC Pipe, that follows immediately after the RC Hammer.
During Reverse Circulation drilling, the first Dual-Tube RC pipe following the RC Hammer, is suffering considerable premature wear and tear, as a result of the constant shock force placed on its inner tube by the continuous realignment of feeding angle of the formation cuttings traveling from the drilling bit back to the surface. Once the inner tube is damaged beyond operating specifications the entire Dual-Tube RC pipe has to be discarded or repaired, extensively increasing drilling costs to the operator. To overcome this problem a Backreamer adapter is placed between the RC hammer and the first RC pipe, which acts as an inexpensive damage absorber, taking on the stress of the alignment of the samples, before feeding them into the expensive Dual-Tube RC Pipe for further transport to the surface. Once Backreamer's inner tube has deteriorated beyond operational specifications and needs replacement, the Backreamer is easily disassembled and the inner tube is replaced on the spot, allowing for continued operation with minimal cost. The entire replacement operation takes a fraction of the costs and time needed for repair and/or replacement of the entire Dual-Tube RC Pipe would cost.

Back Reamer (Backreamer) adapter protects the RC Hammer and the inner parts of the Drill Bit from abrasive damage during drilling string extraction. The Backreamer adapter is fitted with several heavy duty Hard-Pads, which are acting as a makeshift drill bit, working in direction of the drill string extraction and preventing damage to the rear parts of the RC hammer and drill bit from the sample cuttings that might have been dislodged from the borehole. The Backreamer Hard-Pads are highly resistant to abrasive damage and therefore will never require replacement before the need for replacement of the top-sub (Backreamer outer body).

Back Reamer Inner (Lift) Tube

Back Reamer Outer Body