Pipeline pig and launching apparatus

摘要

The present invention provides a pipeline pig (10) comprising an elongate body (12) and annular front and rear supports (26,30) projecting radially from the body (12). Each support (26,30) has an upstream side and a downstream side, with the front support (26) including at least one first fluid passage (18) permitting fluid flow from the upstream side to the downstream side. and the rear support (30) including at least one second fluid passage (22) permitting fluid flow from the upstream side to the downstream side. The pig further comprises a launch valve (50) adapted to move from an open position to a closed position to close the at least one first fluid passage (18), and a control means adapted to control the closing of the launch valve (50). A launch trap for launching pigs into a pipeline is also provided.

主权项

1. A pipeline pig comprising:
an elongate body having a longitudinal axis; annular front and rear supports projecting radially from the elongate body, wherein each support has an upstream side and a downstream side, the front support forming therethrough at least one first fluid passage permitting fluid flow from the upstream side of the front support to the downstream side of the front support, and the rear support forming therethrough at least one second fluid passage permitting fluid flow from the upstream side of the rear support to the downstream side of the rear support, wherein the first fluid passage and the second fluid passage are positioned outside of the elongate body; wherein the at least one first fluid passage includes a plurality of circumferentially spaced first fluid passages formed through the front support, outside of the elongate body, and radially offset from the longitudinal axis a launch valve to move from an open position to a closed position to close the at least one first fluid passage, wherein the launch valve comprises:
a valve body and a biasing means for each respective first fluid passage;an annular base member slidingly located on the exterior of the pig body, wherein each valve body is attached to the base member via a valve stem;the valve body slidably engaged with the elongate pig body for moving from the open to the closed position;the biasing means biasing the valve body towards the closed position; anda control means to control the closing of the launch valve, wherein the control means comprises a locking member to lock the valve body in the open position against the force of the biasing means.