Patent ID: 6374838
Filing Date: 2002-04-23
Classification: B08B

Abstract:
A retrievable pig for pulling a tubing into a pipeline for pipeline maintenance or remediation operations, said tubing and said pipeline having an entrant end where said tubing enters said pipeline, said tubing having a distal end at a distance into said pipeline from said entrant end, and said pipeline extending beyond said distal end of said tubing; said tubing and said pipeline having a first internal area within said tubing, a first annular area outside said tubing and within said pipeline, and a second internal area beyond the distal end of said tubing, said retrievable pig comprisinga seal member sealingly engaging between the outer surface of said tubing and the inner surface of said pipeline up to a predetermined pressure differential between said first annular area and said second internal area and not sealing at a differential pressure higher than said predetermined pressure differential, wherein said not sealing is caused by the release of a release mechanism.