Firma Carl Freudenberg

J&ouml;rg St&ouml;ckler

Wolfram Schultheiss

Felix Herberg

The present invention relates to a pleated filter made of a multi-layer filter medium, including at least one filter paper layer having area weights of 30-100 g/m , a microfiber nonwoven fabric layer having area weights 5-120 g/m and a support nonwoven fabric layer made of synthetic, polymeric fibers having area weights of 10-120 g/m . The layers of the pleated filter contain fused polymer areas by which the fabric layers are bonded to the paper layer, and by which the fabric layers are made firmer within themselves. When subject to a fractional efficiency test at an initial pressure difference of at most 180 Pa, at a boundary speed of approximately 2.62 m/s and a flow speed through the filter medium of approximately 0.13 m/s, the pleated filter is able to separate at least 90% of particles greater than 0.3 &mgr;m, at least 92% of particles greater than 0.5 &mgr;m, at least 93% of particles greater than 1 &mgr;m, and at least 97% of particles greater than 3 &mgr;m, as measured using the standard method DIN EN 60312 (IEC 60312) &sect; 5.1.2.5.

Growing community of inventors

Zurich, Switzerland

Jörg Stöckler

Growing community of inventors

Zurich, Switzerland

J&ouml;rg St&ouml;ckler

Jörg Stöckler