Variable Speed Pipeline Pig With Internal Flow Cavity

Abstract

Embodiments provide a housing defining a trailing end, a leading end and longitudinal axis extending therebetween, at least one relief channel extending longitudinally through the housing between the trailing end and the leading end thereof, the at least one relief channel defining an annular wall, a closure member disposed within the annular wall, the closure member operable to engage a first seat to prohibit fluid flow through the relief channel and operable to disengage the first seat to permit fluid flow through the relief channel, and an annular space defined between the closure member and the annular wall, the annular space exhibiting a smaller cross-section than regions of relief channel upstream and downstream of the closure member such that the annular space represents a constriction for fluid flow and the relief channel defines a venturi.

Dependencies are inferred from the claim text.