Granted Patent
Utility
US 4,497,749 · App. 06/556,802
Check valve for ammonia injector apparatus
Inventor:
Theodore R. Strauss
Patented Case
View Patent ↗
Granted: Feb 5, 1985
Filed: Dec 1, 1983
Inventor
Theodore R. Strauss
Assignee (at issue)
Pennwalt 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.