| 摘要 |
A valve-talking device for use in gas masks has two coaxially disposed tubes which are connected together in the front end by a partition that may be a conic expansion of the inner tube. In the space formed between both tubes valves for the exhaled air are mounted. In the portion of the outer tube disposed between the partition and the valves, openings for exhaled air are disposed and the outlet of the front end of the inner tube is closed hermetically by the talking device. The valves for the exhaled air have an annular valve seat and valve membrane which encompass the inner tube. |
