Issued Patents 1989
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4860991 | Safety valve | Ronald E. Pringle | 1989-08-29 |
| 4838355 | Dual hydraulic safety valve | Dwayne Leismer | 1989-06-13 |
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4860991 | Safety valve | Ronald E. Pringle | 1989-08-29 |
| 4838355 | Dual hydraulic safety valve | Dwayne Leismer | 1989-06-13 |