Patent ID: 6840387
Filing Date: 2005-01-11
Classification: B01D

Abstract:
1. Multilayer composite filter medium for serial filtration of an oil, the filter medium having an onflow side and an outflow side with respect to a flow of the oil to be filtered, the filter medium comprising at least two filter layers, a first filter layer of the at least two filter layers having a particle retention size of 60 μm and greater, a second filter layer of the at least two filter layers having a particle retention size of 10 to 60 μm, wherein the at least two filter layers are essentially the same material and each layer of the at least two filter layers has a different respective filtering property and the at least two filter layers being welded to one another at defined regions, and at least one filter layer of the at least two filter layers being arranged on the onflow side and at least one filter layer of the at least two filter layers being arranged on the outflow side.