Filtering apparatus with rotatable filter elements and seal

摘要

A filter has a housing defining a closed chamber around a hollow shaft which is rotatable in the housing and which carries a plurality of filter elements so that fluid can be pumped through the filter elements into the hollow interior of the shaft. The shaft is rotatable with the filter elements relative to the housing for cleaning filter cake off the filter elements between filtering operations. An annular and hollow bellows-type seal surrounds the shaft and has one axial end secured to the housing and an opposite axial end engageable with the shaft for sealing the shaft relative to the housing. This bellows-type seal is made of thin and flexible stainless steel. The inside of the seal may be pressurized by a liquid or gas to force the end of the seal against the shaft and form a tight connection therebetween.