| 摘要 |
An air filter and frame that cooperate to require alignment of the filter in a desired orientation in order for insertion to occur. At least one edge of the filter is offset from a right angle relative to other edges and the faces of the filter, and an obstruction is formed in the frame so that the filter can be inserted into the frame in only the desired orientation. Preferably two opposing edges of the frame are angled, and obstructions, such as small rails, are mounted in opposing sidewalls of the frame. |
