Drill string safety and kill valve

摘要: A drill string safety and kill valve for a of pipe used drilling wells including tubular body connectible in the pipe, ball mounted to rotate between open closed positions controlling flow through body, longitudinally movable operator connected with valve, spring biased flapper permit downward close responsive upward raising side port provided positioned upwardly when is pumping fluids downwardly into bore lower seat moved by fluid allow well killing after closure. During normal operations are pumped valves. sudden pressure surge closes which turn valve. Heavier may then be around pushing away from enter formation being drilled.