ENHANCED CROSS-FLOW WITH TWO JET DRILLING

摘要

This invention relates to hydraulic circulation systems for cleaning holes being drilled in rock and earth with drilling bits. One of the limiting parameters in three-cutter drill bits in the past is the lack of space for fluid flow passage from the hole bottom to the top of the bit. The present invention overcomes this deficiency of the prior art by providing a drill bit having three cone-shaped cutters and formed with two drilling fluid nozzles on opposite sides of one of the cutters and with an enlarged return passage for the drilling fluid formed between the other two cutters. Flow restrictors adjacent the two nozzles restrict the flow of return fluid in those areas. A flow diverter in the dome area of the bit extends into the space between the cutters to better direct fluid across the bottom of the hole where cuttings are being generated by the cutter teeth.