Granted Patent
Utility
US 4,907,441 · App. 07/236,936
Apparatus and method for identifying or measuring gas or liquid borne substances
Inventor:
Harold V. Shurmer
Patented Case
View Patent ↗
Granted: Mar 13, 1990
Filed: Aug 26, 1988
Inventor
Harold V. Shurmer
Assignee (at issue)
NATIONAL RESEARCH DEVELOPMENT CORPORATION
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.