| 摘要 |
<p>An air filter, comprising: a vent pipe (110); a filtering element (130) disposed in an airtight manner external to the vent pipe (110) and used for air filtration; a first one-way valve used to open and close the vent pipe (110); and a second one-way valve (120) used to allow the air to pass through the filtering element (130) when open, and to prevent the air from passing through the filtering element (130) when closed; during the operation of the filter, the second one-way valve (120) is closed when the first one-way valve is open, and the second one-way valve (120) is open when the first one-way valve is closed.</p> |
