Plunger with flow passage and improved stopper

摘要

A plunger for use in downhole tubulars in wells which produce fluids and/or gases under variable pressure, which has an internal passage to facilitate more rapid descent of the plunger to the well bottom or well stop. The plunger has a stopper housed inside a chamber that is actuated when the plunger and stopper stem reach bottom or a well stop and which is held in a closed position by the build up of pressure below the plunger. The plunger may also have a jacket mounted about a core which has sealing, holding, and lifting capabilities. The plunger may also have fingers which project inwardly from the underside of the jacket toward the inner core which may also be grooved and which provides an inner turbulent or labyrinth-type seal.