Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5297579 | Ball and seat-type check valve for downhole rod pump | Douglas A. Jensen | 1994-03-29 |
| 5249936 | Downhold reciprocating pump with automatically trippable travelling valve for prevention of gas lock | Douglas A. Jensen | 1993-10-05 |
| 5117861 | Ball and seat-type valve for downhole rod pump | Douglas A. Jensen | 1992-06-02 |