US Patent 7519158 Pumping schemes for X-ray tubes with ferrofluid seals

A system for mitigating a gas load imposed upon a high vacuum chamber, thereby reducing the overall pressure, includes a device mounted onto a rotating gantry. The device has a first chamber enclosing a high vacuum and a first region in which anode bearings are positioned. A rotatable shaft has a first portion extending into the first chamber and a second portion extending into the first region. A ferrofluid seal is positioned about the rotatable shaft and positioned between the first portion and the second portion, the ferrofluid seal fluidically separating the first chamber from the first region. At least one pressure-reducing unit is fluidically connected to the first chamber.