| 摘要 |
An improved rotating diamond bit for earth boring is devised by incorporating generally triangular, prismatically shaped synthetic polycrystalline diamond elements in the teeth of the boring bit. The polycrystalline diamond elements are set on lands defined on the bit face such that two opposing triangular faces of the prismatic diamond element form a dihedral angle in the direction of travel of the element defined by the bit rotation. The polycrystalline diamond element is thus inclined with respect to the direction of linear travel of the element when the bit rotates. In other words, the normal to the parallel opposing triangular faces of the diamond element is acutely inclined with respect to the direction of travel of the element. A shoulder-to-gage transition pattern of the junk slot, waterway and collector is arranged to uniformly distribute the flow of fluid across the shoulder to guage transition. Further, the distribution of fluid from the central conduit within the longitudinal core of the bit to a plurality of nozzles which merge with corresponding waterways on the bit face is arranged such that fluid is preferentially delivered to a radially innermost nozzle and thereafter in a graduated series of steps in lesser amounts to a series of sequenced nozzles more radially disposed from the center of the rotating bit.
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