18.104.22.168 Rotation via sliding gaskets with pumped interspaces
The only way to manufacture a manipulator with a free passage and flanges that are freely rotatable to one another, is by using sliding gaskets. Since a sliding gasket alone does not provide a UHV-tight separation, multiple are wired in series and the interspaces are evacuated. Generally three special PTFE sliding gaskets are installed in series. For the first interspace one backing pump is sufficient. If UHV conditions should prevail in the interior, an additional interstage pumping is required, to which a high vacuum pump will be connected.