Issued Patents All Time
Showing 1–5 of 5 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6595716 | Cam lever assembly for manhole center | Henry Knaack, Jr. | 2003-07-22 |
| 6454237 | Air activated internal valve | Robert David Weichers, Brent Stewart Hanson | 2002-09-24 |
| 5275202 | Adjustable emergency relief vent with surge protection | — | 1994-01-04 |
| 5244181 | High flow internal emergency valve | — | 1993-09-14 |
| 5048553 | Relief valve with overturn surge control for storage tank | — | 1991-09-17 |