| 摘要 |
<p>Device for keeping dust poor the air in a space (15) having a frontal opening and a back wall containing filters (10) feeding filtered air to the space, a further filter 8 being arranged at the upper side of the opening, which filter 8 has a vertically downward air exit, the velocity of the air from the further filter 8 being higher than that leaving the back wall filters 10, the air for both types of filters being sucked in below the opening (at 1a, 1b and 1c).</p> |
