Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5635061 | Plate shifter mechanism | Wesley G. Koops, David J. Spyker | 1997-06-03 |
| 5567327 | Air-assist discharge of filter press cake | Joel D. De Haan, Daniel De Haan, Gregory De Haan, David J. Spyker, David P. McLeod +1 more | 1996-10-22 |