Patent ID: 8485225

Claim:
A flow control screen having a fluid flow path between an interior of a base pipe and a filter medium, the flow control screen comprising: a housing positioned about the base pipe having an opening with a radially reduced portion and a seat; and a valve assembly positioned in the opening and disposed within the fluid flow path including a valve plug, a ball retainer and a piston body having a collet assembly that is radially outwardly constrained by the radially reduced portion of the opening in a first position to prevent the valve plug from entering in the piston body and radially outwardly unconstrained by the radially reduced portion of the opening in a second position, wherein an internal differential pressure seats the valve plug on the seat to prevent reverse flow; wherein a predetermined internal differential pressure shifts the piston body from the first to the second position while continuing to prevent reverse flow; and wherein, in the second position, an external differential pressure causes the valve plug to contact the ball retainer, thereafter allowing reverse flow.