Respirator filter having a pleated filter layer

摘要

The filter medium of the present invention includes a pleated filter layer and a flat filter layer adjacent to the pleated filter layer. Both the pleated filter layer and the flat filter layer may contain a thermoplastic material allowing the filter layers to be joined using ultrasonic welding or heat sealing and facilitating manufacturing. The filter medium has a small height which makes it appropriate for use in flat fold respirators and flat filters.