Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4809735 | Valve and tapping tee apparatus and method | Frank R. Volgstadt, Ralph L. Hart | 1989-03-07 |
| 4730636 | Valve and tapping tee apparatus and method | Frank R. Volgstadt, Ralph L. Hart | 1988-03-15 |
| 4216793 | Shutoff valve | Frank R. Volgstadt, David P. Passerell, Raymond A. Day | 1980-08-12 |