Check valve assembly

摘要

A check valve assembly for use in a drill string to limit reverse flow of drilling fluid through the string while permitting such fluid to be pumped freely into the well under normal conditions. The assembly may include: a valve body having a longitudinal flowbore therethrough; a valve seat at one end of the flowbore; a pair of inclined cylindrical recesses in the valve body communicating with the flowbore; and a ball member normally disposed in either one of the recesses and movable into the flowbore for sealing engagement with the seat in response to a predetermined rate of reverse flow through the flowbore.