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Crossflow rotary cone rock bit with extended nozzles

  • US 4,687,067 A
  • Filed: 05/01/1986
  • Issued: 08/18/1987
  • Est. Priority Date: 05/01/1986
  • Status: Expired due to Term
First Claim
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1. A rotary cone rock bit for use in an earth formation, the rock bit being run with hydraulic fluid, the rock bit comprising:

  • a rock bit body having a first open pin end adapted to be connected to a drillstring and a second cutting end, said second cutting end consisting of three rotary cones rotatively retained on journal bearings extending from three 120°

    rock bit leg segments connected to a dome portion formed by said bit body, said bit body further forming a chamber therein for receiving said hydraulic fluid, said chamber is in fluid communication with said first open pin end; and

    a pair of mini-extended nozzles, each of said nozzles forming a first entrance end and a second exit end, said nozzles are connected to a dome portion formed by said bit body, said first entrance end of each of said nozzles being in fluid communication with said chamber, each mini-extended nozzle is positioned in said dome portion of said rock bit between two of the three 120°

    leg segments to direct said hydraulic fluid across said cutting end of said rock bit, a nozzle passage profile formed by each of said mini-extended nozzles define a streamlined entry transition sat said first nozzle entrance end from said dome portion to said entrance end, and a streamlined nozzle throat portion nearest said first nozzle entrance end, said passage further extends from said streamlined throat portion to said second nozzle exit end, said nozzle passage profile is adapted to accelerate hydraulic fluid therethrough to lift cuttings from a bottom of a borehole sweeping said cuttings across said second cutting end and to minimize cavitation and pressure losses associated with the extended portion of each of said mini-extended nozzles, said pair of mini-extended nozzles have sufficient length to create an area of low energy hydraulic fluid bounded on one side by said rock bit dome and limited by a plane established by the discharge fluid from an end of said nozzles, allowing free movement of detritus from said dome to a borehole cut by said rock bit.

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