@sri_srikrishna @TySopko It works that way in HVAC systems usually. I haven't see dirty CR box filters yet, so I can't be sure, but my guess is pressure drop across the filter (especially if dirty) is much larger than open air.
@sri_srikrishna@TySopko通常在暖通空调系统中是这样工作的。我还没有看到脏的CR箱过滤器，所以我不能确定，但我猜过滤器的压降（尤其是脏的情况下）比露天大得多。