Issued Patents All Time
Showing 1–7 of 7 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 8171955 | Emergency relief vent for fuel storage tanks | Donald R. David, George Andrew Borst, Gabriel R. Rodriguez | 2012-05-08 |
| 7584766 | Overfill prevention valve for shallow tanks | Donald R. David | 2009-09-08 |
| 6536465 | Filling limitor for small, shallow liquid storage tanks | Donald R. David, Francis L. Miller | 2003-03-25 |
| 5531247 | Temperature and pressure resistant shutoff valve | Donald R. David | 1996-07-02 |
| 4869342 | Drive in manhole step | — | 1989-09-26 |
| 4610330 | Drive-in manhole step construction | — | 1986-09-09 |
| 4181238 | Venting tank closure | Paul W. Arnold, William L. Scofield, Vern D. Scott | 1980-01-01 |