Magnetically Coupled Mixer with Thrust Bearing Friction Control

摘要

Magnetically coupled mixer having an impeller magnetically coupled to a drive shaft and thrust bearings that support the impeller. The drive shaft can be moved along its axis, and an upwardly directed axial force is applied to the drive shaft to partially offset downward forces exerted by the impeller and thereby reduce friction between the thrust bearing surfaces while maintaining contact between them. In one disclosed embodiment, the force is applied to the drive shaft by a pair of magnets arranged so that the magnetic fields interact to produce the force, and the magnitude of the force is controlled by adjusting the distance between the magnets. The forces exerted by the impeller can be monitored and utilized in controlling the magnitude of the force applied to the shaft.

主权项

1. A mixer for an aseptic liquid, comprising a base having upper and lower end portions and an axially extending bore that opens through the lower end of the base, an impeller rotatably mounted on the upper portion of the base with axially facing thrust bearing surfaces on the base and the impeller in load supporting contact with each other, an axially adjustable drive shaft that rotates within the bore, coupling magnets affixed to the drive shaft and impeller which produce interacting magnetic fields that constrain the impeller for rotational and axial movement with the drive shaft, and means operatively connected to the lower portion of the drive shaft for adjusting the axial position of the shaft to apply an upwardly directed, controlled force to the impeller to partially offset downward forces exerted by the impeller and thereby control friction between the thrust bearing surfaces while maintaining contact between them.