| 摘要 |
<p>A non-woven filter (4) having air intake side (5) and air outlet side (6), is folded so as to form fold peaks (2) and fold valleys (3). Another non-woven filter (7) is arranged at the air intake side of the folded filter, and bonded to the folded filter by ultrasonic welding at the contact points (9). An independent claim is included for filter system manufacturing method.</p> |
