1. Field of the Invention
The present invention relates to pumps which operate on the gerotor fluid displacement principle and more particularly to improved pump constructions for implementing this principle by means of magnetic coupling into a sealed pumping compartment.
2. Description of Prior Art
In order to isolate the handled fluid from the environment of the pump motor, a variety of pump configurations have been devised wherein there is a magnetic field coupling between a motor shaft and a drive shaft for the driven pump member. U.S. Pat. Nos. 2,970,548 and 2,996,994 are exemplary of concentric and axial approaches for such magnetic couplings. U.S. Pat. No. 4,526,518 discloses an application of the axial coupling approach to supply drive to the shaft of a male element of a gerotor pump.
As is described in the aforementioned '518 patent, gerotor pumps offer advantages as to pumping efficiency and low friction. Other advantages of such pumps include quietness in operation and self-priming modes of operation. While the '518 pump does successfully implement the magnetic drive of gerotor elements, it is relatively complex in construction and has a fairly large number of parts.