| 摘要 |
FIELD: mining.SUBSTANCE: drill bit comprises hollow body with connection thread and vanes reinforced with rock-crushing elements and flushing system including pressure and dual takeoff channels. Drill bit is equipped with extra throttling valve arranged inside the body and composed of cylinder with slots at its outer surface aligned partially with said pressure and offtake channels. Note here that said cylinder is rigidly connected with said body by bimetal plates.EFFECT: higher efficiency of drill bit operation owing to improved flushing.3 cl, 3 dwg |
