Multi-layered microfiltration medium
AssigneeDonaldson Company, Inc.
InventorsMarty A. Barris, Richard L. Zelinka
Life of this patent
Estimating the term…
Abstract
A multilayered microfiltration medium exhibiting high particle capture efficiency and minimal flow restriction having a base substrate layer, a fine fiber filtration or efficiency layer deposited on and adhered to the substrate layer and a nonhandleable, non-self-supporting protective cover layer which is self-adhering to the fine fiber layer and has a very smooth outer surface. Suitable cover layer materials include polystyrene and polycarbonate fibers.
Claims21
A handleable, self-supporting and durable multilayered microfiltration medium having a high particle capture efficiency and minimal flow restriction comprising:
- a self-supporting porous substrate layer having a fine fiber filtration layer deposited on and adhering thereto;
- and a porous nonhandleable fiber cover layer deposited on and adhering to said filtration layer, said cover layer being about one to two fibers thick and completely self-adhering to said filtration layer.
A handleable, self-supporting and durable multilayered microfiltration medium having a high particle capture efficiency and minimal flow restriction comprising:
- a self-supporting highly permeable substrate layer, said substrate layer providing a support structure for said medium and having a low relative efficiency and low relative flow restriction;
- a thin efficiency layer of fine fibers having a diameter less than about 0.5 micron, said efficiency layer deposited on and adhering to said substrate layer and having a thickness from about 0.2 to 80 microns and a basis weight from about 0.6 to 240 micrograms/cm.sup.2 ;
- and
- a nonhandleable, non-self-supporting protective cover layer of fibers having a diameter from about 5 to 30 microns, said cover layer formed and deposited on said efficiency layer and having a thickness from about 5 to 60 microns and a basis weight from about 0.04 to 0.5 millidrams/cm.sup.2, said cover layer being self-adhering to said efficiency layer.
A handleable, self-supporting and durable multilayered microfiltration medium having a high particle capture efficiency and minimal flow restriction comprising:
- a self-supporting highly permeable substrate layer, said substrate layer providing support structure for said medium and having a low relative efficiency and low relative flow restriction, said substrate layer contributing no more than about 20% of the medium's total efficiency and flow restriction;
- a thin, non-self-supporting efficiency layer of fine fibers having a diameter less than 0.5 micron, said efficiency layer deposited on and adhering to said substrate layer and having a thickness from about 0.2 to 80 microns and a basis weight from about 0.6 to 240 micrograms/cm.sup.2 ;
- and a non-handleable, non-self-supporting protective cover layer of fibers having a diameter from about 5 to 30 microns, said cover layer having a thickness from about 5 to 60 microns, a basis weight from about 0.04 to 0.5 milligrams/cm.sup.2 and a volume fraction of solids of less than 10%, said cover layer formed and deposited on said efficiency layer, said cover layer being nonlaminated and self-adhering to said efficiency layer and having a very smooth outer surface, said cover layer increasing said capture efficiency of said medium less than about 0.1% and increasing said flow restriction of said medium less than about 0.001 inches of water.
Dependencies are inferred from the claim text.