| 摘要 |
<p>The filter medium (20) of the present invention includes a pleated filter layer (22), and a flat filter layer (24) 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, facilitating manufacturing. The filter medium (20) has a small height which makes it appropriate for use in flat fold respirators and flat filters.</p> |
