Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 6629621 | Gauge hatch with liquid seal | Thomas C. Piotrowski, Baohai Liu | 2003-10-07 |
| 6244457 | Gauge hatch with diaphragm and liquid seal | Thomas C. Piotrowski | 2001-06-12 |
| 6056005 | Vent valve with liquid seal | Thomas C. Piotrowski, Baohai Liu | 2000-05-02 |