Abstract: A spin-on barrier filter cartridge is provided in which an inverted frustum-shaped filter media defines a clean air chamber. A bottom cap blocks air flow through a bottom of the chamber and a top cap restricts air flow through a top of the chamber into a passage concentric with the chamber. The filter media has a pleated cross-section and an inverted frustum-shaped screen-like core abuts the inner apices of the pleated media. The bottom and top caps are fixed to the bottom and top edges of the media to hold the cartridge together and also to seal the junctions against air flow. A nipple extends upwardly from the top cap and defines the concentric passage. The nipple is threaded for spin-on connection to the vacuum in a direction such that the engagement is tightened in response to vortical air flow in the chamber.