| 摘要 |
Air filter (20), especially a pollen filter in which a portion of a porous sheet consists of a pleated strip (21) held in a leakproof manner in a rectangular frame (23) whose two opposite uprights (24, 25) are integrally attached to the outermost edges of the pleated strip, characterised in that each upright (24, 25) of the frame (23) supports a part (21a, 21b) of the pleated strip and is extended along the said strip by a pair of crosspieces (26, 26' - 27, 27') respectively bearing on the opposite sides of the strip (21) and in that the pair of crosspieces (27, 27') which is connected to one of the uprights (25) is fitted so as to move along the crosspieces (26, 26') which are connected to the other upright (24) with the aim of provisionally reducing the size of the frame (23). <IMAGE>
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