| 摘要 |
Filtering foreign particles from air includes a filter unit (13) having electrodes (16, 17) of different electrical potentials (+,-) sufficiently low to avoid ionization of foreign particles. Flow-through of air of foreign particles under the effect of an electric field cause entrapment of the foreign particles so as to provide fine filtration. Air flow past electrodes (16, 17) are parallel or transverse. The electrodes (16, 17) are symmetrically arranged about a central axis (22). A retaining sheet (28) is placed between electrodes (16, 17). |
