In 2006 the large Danish pump manufacturer Grundfos asked for a mathemtical
analysis of the pump and brought the problem to the
57th European Study
Group with Industry in Denmark.
The report can be found
here.
The original design is based on hypo- and epi-cycloid and below the constructions are explained.
| Curves | Number of "teeths" on the stator and rotor | ||
|---|---|---|---|
| Hypo-cycloids | 2:1 | 3:2 | 4:3 |
| Epi-cycloids | 2:1 | 3:2 | 4:3 |
| Hypo- & epi-cycloids | 2:1 | 3:2 | 4:3 |
| New designs | 3:2 | ||