| US 7,614,844 B2 | ||
| Vacuum pumping arrangement | ||
| Nigel Paul Schofield, Horsham (United Kingdom) | ||
| Assigned to Edwards Limited, Crawley, West Sussex (United Kingdom) | ||
| Appl. No. 10/581,696 PCT Filed Dec. 08, 2004, PCT No. PCT/GB2004/005211 § 371(c)(1), (2), (4) Date Jun. 06, 2006, PCT Pub. No. WO2005/059367, PCT Pub. Date Jun. 30, 2005. |
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| Claims priority of application No. 0329034.3 (GB), filed on Dec. 15, 2003. | ||
| Prior Publication US 2007/0140833 A1, Jun. 21, 2007 | ||
| Int. Cl. F04D 19/04 (2006.01) | ||
| U.S. Cl. 415—90 [415/121.2] | 27 Claims |
| 1. A regenerative pumping mechanism comprising
a rotor having a series of blades positioned in an annular array on one side of the rotor and extending axially into an annular
channel of a stator within which the blades rotate, and
means for actively controlling relative axial movement between the rotor and the stator so as to control the axial clearance
between the rotor and the stator wherein the means for actively controlling relative axial movement comprises an axial magnetic
bearing having an electromagnet arranged to draw the rotor towards the stator; and
wherein the electromagnet is mounted on the stator of the regenerative pumping mechanism.
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