Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 4580443 | Detecting leaks | Peter E. G. Marshall, Francis R. Piper, John F. Wilson | 1986-04-08 |
| 4577490 | Detecting leaks | Peter E. Johnson, Peter E. G. Marshall, Francis R. Piper, Iain H. Murdoch | 1986-03-25 |