JETTING NOZZLE OF DRILL BIT Russian patent published in 1998 - IPC

FIELD: mining, in particular, rock-cutting tools for hole drilling. SUBSTANCE: jetting nozzle of drill bit has long cylindrical metal body with outer thread and central channel of variable section with uniform roughness of wall surface ensured by elastoplastic coating made integral with packing ring. Coating projects beyond the body lower end face through a valve equalling at least three diameters of coated central channel made narrowing on projecting section with conical transition section. EFFECT: higher efficiency of operation of drill bits with jetting nozzles. 1 dwg