NOZZLE FOR ONE-PIECE DRILLING TOOL Russian patent published in 1996 - IPC

FIELD: drilling tool, in particular, one-piece tool with blades or crowns of diamond bit, crystalline poly-diamond, tungsten carbide etc. SUBSTANCE: passage 3 of the nozzle of the one-piece drilling tool becomes wider as goes from inlet outlet. Alpha angle of passage 3 expansion is less than 30 degrees. Passage 3 may have diverging part 7, cross section of which becomes smaller as it goes along the direction of liquid flow. Diverging part 7 takes a part of passage 3 length beginning from its inlet. Expanding part follows the diverging part 7. The expanding part takes the remaining part of the passage 3. Passage 3 may have cylindrical part. Cylindrical part takes a portion of passage 3 length beginning from its inlet. Expanding part of passage 3 follows cylindrical part. The expanding part takes the remaining portion of passage 3 length. There is a shift or step on lateral wall 4 in the area of interconnecting diverging part 7 or cylindrical part of passage 3 with its expanding part. The shift or step goes along all circumference of wall 4 and is oriented in the direction of passage outlet. The shift or step forms annular space together with expanding part of passage 3. EFFECT: high capacity. 4 cl, 4 dwg