Patent ID: 8042694

Claim:
An apparatus for forming a filter media including a gathered sheet of porous filter material, the apparatus comprising: a first and a second gathering roller, each including an outer periphery thereof having a plurality of circumferentially spaced round ended protrusions extending radially outward therefrom; the first and second gathering rollers being mounted for rotation in a spaced and timed relationship to one another such that the protrusions of one gathering roller are disposed between adjacent protrusions of the other gathering roller, grooves being defined between adjacent protrusions, for forming gathers without folding or pleating in a sheet of porous filter material fed between the first and second gathering rollers, with the protrusions and outer peripheries of the first and second gathering rollers configured and spaced from one another such that the sheet of porous filter material is not compressed between any portion of the protrusions of the first gathering roller and any portion of the protrusions of the second gathering roller, and wherein the protrusions of each gathering roller do not seat at the bottoms of the grooves of the other gathering roller.