US Patent 10450815 Flow restrictor system

A system includes a flow restrictor assembly configured to be coupled to an annular structure having a central bore. The flow restrictor assembly includes one or more adjustable segments configured to move relative to the annular structure between a retracted position in which the one or more adjustable segments do not extend into the central bore and an extended position in which the one or more adjustable segments extend into the central bore to reduce a cross-sectional flow area of the central bore by between approximately 5 to 95 percent to restrict fluid flow through the central bore.