摘要 |
A respirator 10 that has a mask body 12 and a harness 16 has an exhalation valve 23 that includes a valve seat 36 and a flexible flap 42. The valve seat 36 has an orifice 38 and has a noncircular seal surface 40 surrounding the orifice 38. The flexible flap 42 is secured to the valve seat 36 at a centroid of the orifice and has a variable stiffness structure. The variable stiffness structure allows the flap to equally deflect under a given load at different distances from the centroid at the noncircular seal surface. An exhalation valve having this construction may beneficially optimize pressure drop and overall valve performance for applications where valve space may be limited. |