| 摘要 |
<p>A continuous method for manufacturing an electret filter medium from dielectric material having an open or porous structure, said method comprising the step of continuously feeding a web of dielectric material (122) with a substantially closed dielectric foil (127) adjacent to at least one major phase thereof into a corona discharge device (124) reducing the thickness of the web of dielectric material and charging the web of reduced thickness dielectric material by means of a corona discharge and to apparatus for carrying out said method. </p> |
