SEMIMASK FOR RESPIRATOR Russian patent published in 2002 - IPC

FIELD: device for protecting individual's breathing organs from hazardous industrial environment. SUBSTANCE: semimask has portion adjoining to obturator and made in the form of four conjugated arcs of circle and portion arranged in vertical plane perpendicular to front plane of semimask and made in the form of three conjugated arcs of circle, with middle concave arc of circle extending into hemisphere. Obturator has portion adjoining to chin and extending in horizontal plane intersecting hemisphere and arranged below circular portions for attachment of filtering cartridges and expiration valve. Chin portion of semimask is formed as arc of circle extending inside hemisphere and conjugated with vertical arcs of circle of front part adjoining to cheeks. Width, radius and bending angle of obturator, which are forming its section contour are gradually increasing from upper nose part to chin part along entire perimeter of obturator contour or mentioned geometric values are constant in chin part thereof. EFFECT: increased efficiency by optimal distribution of pressure over obturator contour and reliable attachment. 3 dwg, 1 ex