Donaldson Comapny, Inc.

Allan L Liebrenz

Andrew J Dallas

Stanley B Miller, Iii

Paul L Kojetin

Katsushi Isogawa

Kirk A Schneider

Henry J Drasner, Iii

Cynthia D Bellefeuille

Suzan K Nunnink

A filter is provided which includes an organic vapor adsorbing layer, a first particulate removal layer, and a second particulate removal layer. The organic vapor adsorbing layer includes porous adsorbent beads which allow air or gas to flow therethrough with little resistance and provide increased surface area by virtue of the pores. The particulate removal layer can be made from an electrostatic and/or polytetraflouroethylene. The filter can have a figure of merit greater than about 10 and a capacity for permanently adsorbing organic vapors, wherein the figure of merit is calculated based upon a fractional efficiency determined for particles having a size of 0.3 .mu.m in an air flow having a velocity of 10.5 ft./min and for Frazier permeability at 0.5 inches H.sub.2 O.

Filter and method for making a filter

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Excelsior, MN, United States of America

Allan L Liebrenz