Fabric material composite construction for use as a filter means

A method for protecting inner parts of a cellular phone from magnetic and powder particles, said method comprising:

• providing a fabric material composite construction that is adapted for acoustical applications, said fabric material composite construction consisting of a knitted fabric made of a synthetic thread and having square openings with a square opening size from 5 μm to 2000 μm and supporting one or more layers of nanofibers having a nanofiber diameter from 100 to 900 nm, said nanofibers being coated on said knitted fabric by an electro-spinning coating method such that said nanofibers are embedded in said knitted fabric thereby forming with said knitted fabric a cohesively bound filtering means adapted to prevent particles having a particle size from 1 to 2 μm from passing through said filtering means, said fabric material composite construction having an acoustical impedance adapted to allow sound waves to pass through said fabric material composite construction, said cohesively bound filtering means having a filtering efficiency of 99% for particles having a particle size up to 2 μm, and
• positioning said composite filtering fabric material in said cellular phone where said composite filtering fabric means protects inner parts of said cellular phone from magnetic and powder particles while allowing sound to pass therethrough.