CONICAL AIR FILTER

摘要

An air duct system includes a conical fabric filter (22) disposed within a cylindrical air duct. In some embodiments, both the filter and the air duct are inflatable. A fabric collar (40) and a pair of zippers not only allow the filter to be readily removed for cleaning, but also allow the air duct system to continue operating with the filter removed. Pleats (60) can provide the filter with more surface area, and the pleats can be interconnected in an alternating pattern to inhibit the filter from over inflating.