Evertable drum centrifuge filter

An evertable drum centrifuge comprising:

• a housing extending along an axis;
• a hollow filter drum rotatably mounted in the housing about the axis and having a front end wall formed with a fill opening centered on the axis;
• an evertably mounted filter medium inside the filter drum;
• a nonrotatable fill tube extending along the axis and having a back end;
• a fill head complementarily engageable in the fill opening and fitted in a closed position in the fill opening;
• means for introducing a suspension to be filtered through the fill tube and fill opening into the drum;
• a bearing rotatably supporting the fill head on the fill-tube back end;
• a static seal engageable between the fill head and the fill opening;
• a pair of dynamic seals flanking the bearing, defining with the head and fill tube an annular compartment surrounding the fill tube, and each having
• a head ring fixed rotationally on the head and having a face,
• a fill-tube ring fixed rotationally on the fill tube and having a face axially
• engaging the face of the respective head ring, and
• a spring urging the faces of the respective fill-tube ring and head ring axially together;
• and
• means for pressurizing the compartment with a fluid and forcing the fluid from the compartment between the faces of the dynamic seals.