VALVOLA DI SICUREZZA E DI SAGGIO PER PROVA DI PRESSIONE DEI TUBI DI TRIVELLAZIONE

摘要

A drill pipe tester valve includes a spherical valve member supported from an upward facing surface of a housing so that downward forces exerted on the valve member in its closed position, due to fluid pressure in a string of pipe above the valve member, are transmitted substantially entirely to said housing. A latching device is provided for latching the spherical valve member in its closed position as the string of pipe and tester valve are lowered into a well and for subsequently releasing the spherical valve member and allowing it to move to its open position when the string of pipe and tester valve are finally positioned within the well.