Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4558874 | Valve stem packing assembly | Peter C. Williams, Ulrich H. Koch, Edward M. Yusko, Jr. | 1985-12-17 |
| 4538790 | Valve stem packing assembly | Peter C. Williams, Ulrich H. Koch, Edward M. Yusko, Jr. | 1985-09-03 |