Patent ID: 8419845

Claim:
An air filter, comprising: a main body, having a containing room, an entrance hole and an exit hole, the entrance hole and the exit hole communicating with the containing room respectively; a pressure fan assembly, being disposed in the containing room, the pressure fan assembly leading air to enter the containing room from the entrance hole and go out from the exit hole; a filter module, comprising a first filter layer, a second filter layer and a frame body, the first filter layer being located in the entrance hole, the second filter layer being located in the frame body detachably, the frame body positioning at one side near the entrance hole of the main body, the frame body being capable of moving pivotally at one side near the entrance hole of the main body; and a fix assembly, the fix assembly fixing the frame body on the main body selectively, wherein the frame body moves between an opening position and a closing position pivotally, when the frame body is located in the closing position, the frame body closes the entrance hole, the fix assembly fixes the frame body on the main body, when the frame body is located in the opening position, the frame body is away from the entrance hole; wherein the first filter layer is located between the pressure fan assembly and the second filter layer when the frame body is located in the closing position, the first filter layer has first filtering passages, the second filter layer has second filtering passages each having a cross-section area smaller than that of the first filtering passage.