Filter and accessory mount for upright vacuum cleaner exhaust port

For use with an air filter adapter base having (a) a base plate with at least one opening therein for the passage of exhaust air therethrough, (b) releasable engagement structure, and (c) a first rib extending substantially continuously around said at least one opening therein and protruding therefrom, an air filter unit comprising:

• a filter carrier having (a) at least one opening therein for the passage of exhaust air therethrough, (b) complementary engagement structure complementary to said releasable engagement structure, and (c) a second rib extending substantially continuously around said at least one opening therein and protruding toward said base when said complementary engagement structure engages said releasable engagement structure;
• and
• a filter, said filter being substantially permanently attached to said filter carrier by being at least tacked thereto;
• wherein:
• when said filter carrier is attached to said base:
• said first and second ribs extend substantially parallel to one another, separated by a separation distance, creating a separation space, and
• said filter is captured between said filter carrier and said base, edges of said filter being captured between said first and second ribs and being deformed into a tortuous path thereby for creating a seal in said separation space against passage of air through said separation space.