دیکشنری تخصصی مهندسی نفت - نسخه آنلاین

n: a device used to restrict fluid flow to one direction. It consists of a polished sphere, or ball, usually of metal, and an annular piece, the seat, ground and polished to form a seal with the surface of the ball. Gravitational force or the force of a spring holds the ball against the seat. flow in the direction of the force is pre- vented, while flow in the opposite direction overcomes the force and unseats the ball.