3m Innovative Properties Company

Jamie A Hern

Simon J Smith

An approach for beneficially incorporating both a solid organic impregnant and a fluid impregnant into filter media particles without the presence or addition of one unduly affecting the performance of the other. The present invention achieves impregnation by combining sublimation and non-bulk absorption techniques. These techniques may be carried out in sequential, simultaneous, overlapping, and/or alternating fashion, or the like. The invention is especially suitable when the filter media particles already contain or are to contain one or more other impregnants, whose function or presence might be adversely affected when conventional methods are used to add the solid organic and fluid materials.

Sublimation of solid organic compounds onto substrate surfaces in the presence of a fluid impregnant

Filter medium includes at least two kinds of filter media particles. A first plurality of filter media particles includes an extended surface area substrate comprising at least one transition metal impregnant. A second plurality of filter media particles includes an extended surface area substrate comprising a tertiary amine impregnant. In preferred embodiments, at least one and preferably both of the kinds of filter media particles is/are substantially free of chromium, and more preferably contain no detectable chromium. The filtering medium has very broad filtering capabilities. The filtering medium successfully achieves performance levels mandated both by applicable industrial filter approval specifications and by international military filter performance specifications.

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Brockville, Canada

Jamie A Hern