| 摘要 |
<p>PURPOSE:To permit the replacement of a filter at an appropriate time by increasing the effective area of an electret filter, reducing the filtration velocity of this filter to reduce the pressure loss thereof and increase the dust collecting efficiency thereof and controlling the filter by a timer. CONSTITUTION:An electric discharge part 1 consisting of a discharge wire 2 and a plate electrode 3 is provided on the upstream side of air flow and an electret filter 6, together with a take-up device 7 therefor, is provided on the downstream thereof. The filter 6 is arranged in a wavy configuration transverse to an air flow passage and the replacement time thereof is controlled by a timer 12. As a result, the pressure loss of filter becomes small with improved dust collecting efficiency and the filter can be replaced at an appropriate time.</p> |
