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US 4,592,815 AGranted
Method of manufacturing an electret filter
AssigneeJapan Vilene Company, Ltd.
InventorEtsuro Nakao
Life of this patent
Estimating the term…
Abstract
The disclosed method provides an electret filter having a permanent electrostatic charge and formed of polymer fibers having an intrinsic viscosity of 1.5 or less. Fibers of the requisite viscosity are formed into a non-woven fabric and fed, at room temperature, through a gap between a discharge electrode and a ground electrode while being tightly pressed against the ground electrode. The ground electrode preferrably presents a polished metal surface for contact with the web.
Claims15
A method of manufacturing electret filters comprising:
- providing a preformed non-woven fabric of non-polar synthetic polymer fibers having an intrinsic viscosity of 1.5 or less;
- providing a ground electrode and at least one discharge electrode adjacent said ground electrode and establishing a high voltage field therebetween;
- passing said preformed non-woven fiber fabric through the high voltage field while in contact with the ground electrode to impart a permanent electrostatic charge to said fabric, said fabric remaining at approximately room temperature as it passes through the high voltage field.
Dependencies are inferred from the claim text.