Filtration arrangement

摘要

Constructions and methods are described for collecting particulate material from gas streams. In one arrangement, there is an outer, air permeable cylindrical liner, and a first region of fibrous depth media positioned immediately adjacent to the air permeable liner. The first region of fibrous depth media includes non-pleated depth media having an average percent solidity within the construction of no greater than about 3%. The first region of fibrous depth media has an upstream side which is secured to the outer, air permeable liner.