Granted Patent
Utility
US 6,338,385 · App. 09/548,807
Retrievable downhole adjustable choke
Inventor:
John D. Muchow
Patented Case
View Patent ↗
Granted: Jan 15, 2002
Filed: Apr 14, 2000
Inventor
John D. Muchow
Assignee (at issue)
Hydril 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.