Granted Patent
Utility
US 5,577,528 · App. 08/342,341
Apparatus for upgrade or repair of in-service pipelines
Inventors:
Narayan C. Saha, Gregory J. Drzewiecki, Chi Lei
Patented Case
View Patent ↗
Granted: Nov 26, 1996
Filed: Nov 18, 1994
Inventors
Narayan C. Saha
Gregory J. Drzewiecki
Chi Lei
Assignee (at issue)
Southern California Gas Company
This patent predates the USPTO's electronic file wrapper — prosecution documents from this era exist only in the Patent Office's paper records. A certified copy of the file history can be ordered from the USPTO's paper archives.