| 摘要 |
PURPOSE:To reduce the types of filter holding rails by forming right and left rails for holding a rough dust filter and an intermediate performance filter in the same size, fully opening the rail at one end of an opening of a panel and partly blocking the other rail at the other end. CONSTITUTION:Recess-shaped filter holding rails 32 having a size larger than the frame width A of a frame 22a above and below a rough dust filter 22, an opening 33 of a panel 36 is opened from the filter 22 to an intermediate performance filter 28, rails each having a size of the frame width B of a frame 28a are formed above and below the filter 28 at one side, and both the rails 32 are formed in the same size at right and left sides. Detaching and attaching means of the filter 28 is so formed as to block about half of the rails 32 by an opening end 34, and an opening end 34a is formed in size larger than the frame width A of the frame 22a at the side of the other filter 22. Even if the filter 22 is intended to be attached to the filter 28 side, it cannot be inserted to prevent the filter from being erroneously inserted. |
