| 摘要 |
1,208,019. Jetting drill bits. GULF RESEARCH & DEVELOPMENT CO. 31 Oct., 1967 [3 Nov., 1966], No. 49310/67 Heading E1F. The life of an earth-boring drill bit jetting nozzle, which allows of the emergence of a high velocity jet of liquid and abrasive particles from the bit, is prolonged by the appropriate shaping of the flow passage through the nozzle. The entry surface of the passage is defined by the rotation about the axis of the passage of an arc of a circle of a radius R of between 12.7 to 444.5 cms., this entry surface merging tangentially with the cylindrical bore of the exit portion T of the nozzle of which the exit bore is smaller than the inlet bore. Reference has been directed by the Comptroller to Specifications 1,136,739 and 1,136,740 |
