Granted Patent
Utility
US 5,311,911 · App. 07/885,075
Tube plug for closing a defective heat exchanger tube, method for closing a defective heat exchanger tube and method for loosening a tube plug
Inventors:
Peter Krausser, Alexander Hummeler
Patented Case
View Patent ↗
Granted: May 17, 1994
Filed: May 18, 1992
Inventors
Peter Krausser
Alexander Hummeler
Assignee (at issue)
Siemens Aktiengesellschaft
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.