DRILL TO MAKE CIRCULAR WELLS Russian patent published in 2015 - IPC E21B4/16 E21B6/00 

FIELD: process engineering.

SUBSTANCE: invention relates to construction and may be used for making of piles foundation. Proposed device comprises assembly of drilling hammers with percussion-type downhole device. The latter comprises one or more percussion-type downhole devices, circular case with ID and OD. Said case houses drilling hammers with percussion-type downhole device arranged in between said ID and OD. Top pipe has one or more outlets. Note here that top pipe is connected to said drilling hammer. Air or fluid pressure control valve is connected to said top pipe. Drive to spin the device connected to aforesaid valve. Every said hammer comprises drill bit locked in circular case by adjacent wedges. Piston is arranged at drill bit top part to transfer percussion force at drilling and has discharge bore. The latter is arranged at drill bit bottom to release compressed air or fluid. Said compressed air of fluid force crushed lumps of rock particles out along case inner and outer surface.

EFFECT: high percussion power.

8 cl, 7 dwg