| 摘要 |
<p>The mask is held by four support buttons and two straps attached having a reverse leverage pulldown effect to pull the mask into contact with the facial area. A concave configured sealing diaphragm on the exhalation valve provides a uniform opening with less effort than is normally encountered in such valves. A staggered anti-inversion rib on the concave underside of the exhalation valve prevents the diaphragm from inverting to a convex configuration. The valve includes an exhalation valve stack and vent that can be covered at a sharply chamfered opening to provide for a pressure fit test. The inhalation port features two unique chamfered exterior rings which mate with a reverse chamfered cartridge. The inhalation valve is mounted on the threaded connector so as to form a slightly concave configuration to minimize the objectionable popping sound.</p> |
