Patent ID: 8636833

Claim:
A method for filtering particles from air laden with water mist comprising the steps of; providing a flow of air laden with a water mist and containing particles that are to be filtered, passing the air flow containing particles and laden with water mist through a filtration medium, said medium having an upstream side and a downstream side relative to the flow of air and comprising a hydrophobic nonwoven web and a nanoweb layer, wherein the nanoweb layer has a basis weight of at least 2 grams per m 2 and is positioned downstream of and in fluid contact with the hydrophobic nonwoven web, and the hydrophobic nonwoven web is positioned so that it faces the air flow; and wherein the filtration medium when exposed to the air flow laden with water mist has a pressure drop measured across the medium which rises by a factor of no more than 10 after exposure to the air flow for 3 minutes.