Wireline safety check valve

摘要

A check valve for wireline operations is employed in oil well drilling where a high pressure is encountered in a well. The check valve permits a wireline to extend through the check valve and a ball chamber therein. The ball chamber has a check ball therein that rests between the wireline and a non restrictive flow passage open to the well, so that upon loss of the wireline the fluid or gas tending to escape forces the ball to block the wireline opening.