Issued Patents All Time
Showing 1–2 of 2 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5246502 | Method of cleaning valve bushings | Alvin J. Matthews, Thomas M. Hartzell, Ronald M. Markos | 1993-09-21 |
| 5146939 | Valve bushing cleaning device and method of cleaning valve bushings | Alvin J. Matthews, Thomas M. Hartzell, Ronald M. Markos | 1992-09-15 |