| 摘要 |
<p>A filter face mask comprises a mask body (1) adapted to fit over a nose and mouth of a wearer, and an exhalation valve (4) mounted to the mask body (1), the exhalation valve (4) comprising a flexible flap (7), a valve seat (5), and a valve cover (6), the valve seat (5) comprising one or more inlet ports (8), which one or more ports (8) are surrounded by a seal surface (9A/9B/9C). The flexible flap (7) has a transverse curvature that is imparted to the flexible flap (7) by the mounting of the flap (7), the mounting of the flap (7) biasing the free portion of the flap towards the seal surface (9C) under neutral conditions while also allowing the free portion of the flap (7) to be lifted from the seal surface (9C) during an exhalation. <IMAGE></p> |
