Filter medium for filtering gases has a pre-deposition layer on crude side of support layer and main deposition layer on pure side of support layer

摘要

The filter medium has a support layer (17) made of filter paper containing cellulose and two filter layers (16,18) made of fleece with different deposition properties. At least one of the filter layers is applied as a pre-deposition layer (16) on the crude side of the support layer (17) and as a main deposition layer (18) on the pure side of the support layer. The filter fineness of the support layer is lower than that of the main deposition layer. Preferred Features: The pre-deposition layer is made of a melt-blown fleece having a density of 5-20 g/m<2> and a fiber thickness of 10-30 micro m. The main deposition layer is made of a melt-blown fleece having a density of 3-20 g/m<2> and a fiber thickness of 3-10 micro m. The cellulose filter paper contains up to 50% glass fibers.