Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| D287871 | Seismic gas shut-off valve | David Ritchie | 1987-01-20 |
| 4565208 | Seismic shut-off valve | David Ritchie | 1986-01-21 |
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| D287871 | Seismic gas shut-off valve | David Ritchie | 1987-01-20 |
| 4565208 | Seismic shut-off valve | David Ritchie | 1986-01-21 |