EXTENDED BIT JET NOZZLE Russian patent published in 1994 - IPC

FIELD: manufacture of drilling bits. SUBSTANCE: cylindrical water course 4 of extended bit jet nozzle has forming section 12 consisting of outlet cylindrical hole of nozzle nominal diameter and converging tube part 14 formed by rotation of curvature comprised of two arcs of same radial round the nozzle axis. Arcs are smoothly conjugated to each other, damper 6 and outlet hole 13 whose length equals 0.1-0.5 of nozzle nominal diameter. Diameter of damper is smaller than maximum diameter of inlet converging tube part 5 by 1.25-1.3 times. Radius of inlet arc is less than that of additional arc by 2.2-2.6 times. Radius of inlet arc is taken equal to 1.8-2.2 diameters of damper. Arcs 15 and 16 may be taken from relation given in invention description. EFFECT: higher efficiency. 2 cl, 3 dwg