Issued Patents All Time
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5567327 | Air-assist discharge of filter press cake | Joel D. De Haan, Gregory De Haan, David J. Spyker, David P. McLeod, Wesley G. Koops +1 more | 1996-10-22 |
| 5456022 | Batch-type sludge drier | David P. McLeod, David J. Spyker, Greg De Haan, Wesley G. Koops, James E. Roelofs | 1995-10-10 |
| 5328617 | Air-assist discharge of filter press cake | Joel D. De Haan, Gregory De Haan, David J. Spyker, David P. Mc Leod, Wesley G. Koops | 1994-07-12 |