Granted Patent
Utility
US 4,911,697 · App. 07/227,346
Chest drainage unit having increased airflow capacity with capability to dampon noise
Inventor:
Michael J. Kerwin
Patented Case
View Patent ↗
Granted: Mar 27, 1990
Filed: Aug 2, 1988
Inventor
Michael J. Kerwin
Assignee (at issue)
Sherwood Medical 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.