A respirator which is in the form of a protective hood is arranged to fit er the head including the face of a wearer, leaving a space between the hood and the wearer's head. A sealing member is provided between the hood and the back and sides of the wearer's head with means normally fitted within the...http://www.google.es/patents/US3963021?utm_source=gb-gplus-sharePatente US3963021 - Respirators
