Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4886539 | Method of vacuum refining of glassy materials with selenium foaming agent | Richard L. Gerutti, David R. Haskins, Ronald L. Schwenninger, Wright M. Welton | 1989-12-12 |
| 4836775 | Air cooled rotary kiln collar | John K. Groetzinger | 1989-06-06 |