| 摘要 |
An air filtration apparatus is disclosed. During inhale response, user's breath opens a first air valve causing air flow through replaceable filter through a chamber to a mouth piece disposed in a user's mouth. During exhale response, user's breath closes first valve causing one or more exhaust valves to open. In one embodiment, inhale and exhale responses are displaced from one another to provide better isolation of replaceable filter.
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