Abstract: An improved air exhauster for a vehicle is provided, comprising a non-woven filter with a covering sheet of material fastened to the filter face. The filter may be assembled into a frame and the covering sheet may acts as valve to allow air outflow from the interior of the vehicle, yet restrict outside noise from entering. The covering sheet may be a relatively more dense non-woven material than the filter or may be a polymer film. The covering sheet may be attached at the centerline of the filter to function as a pleat separator and reduce the incidence of pleat collapse under high flow rate or increased pressure drop.

Abstract: A fibrous filter media is provided for meeting NSF 50 requirements for water turbidity in pools, hot tubs and spas which includes a sheet of nonwoven fibers coated with chitosan, wherein the sheet may be pleated or present in a stacked layer configuration.

Abstract: An improved air exhauster for a vehicle is provided, comprising a non-woven filter with a covering sheet of material fastened to the filter face. The filter may be assembled into a frame and the covering sheet may acts as valve to allow air outflow from the interior of the vehicle, yet restrict outside noise from entering. The covering sheet may be a relatively more dense non-woven material than the filter or may be a polymer film. The covering sheet may be attached at the centerline of the filter to function as a pleat separator and reduce the incidence of pleat collapse under high flow rate or increased pressure drop.