Issued Patents All Time
Showing 1–4 of 4 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 7270140 | Poppet valve assembly | Dennis C. Hatfield, Franklin B. Piehl | 2007-09-18 |
| 7066193 | Poppet shear protection apparatus and system | Franklin B. Piehl, Dennis C. Hatfield | 2006-06-27 |
| 6742538 | Method and apparatus for orbital and seal welded relief device on a compressed gas cylinder | Franklin B. Piehl, Dennis C. Hatfield | 2004-06-01 |
| 6142346 | Cluster-type relief device | Franklin B. Piehl | 2000-11-07 |