Clean pump
AssigneeNtn Corporation
InventorsTsugito Nakazeki, Hiroyoshi Ito
Life of this patent
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Abstract
In a clean pump of the present invention, a magnetic coupling is formed by a permanent magnet attached to a rotor and a permanent magnet attached to an impeller, with a combined electromagnet arranged to be opposed to a soft iron member of the impeller at the side opposite to the rotor. The combined electromagnet is provided with a permanent magnet arranged at one side of its core and two coils wound around the permanent magnet. These coils are zero-power controlled by a control circuit based on outputs of position sensors such that the impeller is supported approximately at the center of a casing by an attracting force of the permanent magnets and an attracting force of the permanent magnet of the combined electromagnet.
Claims7
A clean pump comprising:
- a case member,
- a ring-shaped impeller rotatable about a rotational axis in said case member,
- a rotatable rotor provided opposed to one side of said impeller with said case member provided therebetween,
- passive radial magnetic bearings one provided at said one side of said impeller and the other provided at a side of said rotor opposed to said impeller for radially supporting said impeller,
- an active magnetic bearing including a plurality of combined electromagnets and a permanent magnet disposed opposed to the other side of said impeller with said case member provided therebetween and an electromagnet, for controlling the rotation of said impeller about an axis perpendicular to said rotational axis, and
- controlling means for zero-power controlling said active magnetic bearing.
Dependencies are inferred from the claim text.