PURPOSE: To produce a multilayered metal powder filter having a specified filtration degree or lower and a constant permeation amt. by alternately laminat ing layers (A) having specified properties and layers (B) which are more coarse than the layers (A) to form two or more layers.
CONSTITUTION: This filter is a sintered multilayered metal powder filter and consists of two or more layers of layers (A) and layers (B) alternately laminated. (a) The layer (A) shows such properties that (i) pores of ≤5μm diameter are present in ≥1×103 number per 1mm2 in any cross section of the layer and (ii) pores penetrate the cross section of the filter. (b) The layer (B) shows such properties that (i) pores having larger diameter than the pores 10 the layer (A) are present by ≥1×103 number per 1mm2 in any cross section and (ii) pores penetrate the cross section of the filter. (C) The porosity of the filter is 40 to 70%. Thereby, the obtd. multilayered metal powder filter has about <1μm filtration degree and about ≥0.2l/min/cm2 permeation of nitrogen gas under about 0.2kgf/cm2 pressure difference.
FUJIKAWA TOSHIHARU
NISHI KUNIAKI
