Issued Patents All Time
Showing 1–3 of 3 patents
| Patent # | Title | Co-Inventors | Date |
|---|---|---|---|
| 5960736 | Vacuum level control system using variable frequency drive | David C. Ludington, Fangjiang Guo, James A. Kowalksi | 1999-10-05 |
| 5284180 | Controlling vacuum level with a two-level vacuum system controller and adjustable speed drive | Fangjiang Guo, David C. Ludington, Daniel Aneshansley | 1994-02-08 |
| 5141403 | Two-level vacuum system controller with adjustable speed drive | Fangjiang Guo, David C. Ludington, Daniel Aneshansley | 1992-08-25 |