Filter medium and air filter unit using the same
AssigneeDaikin Industries, Ltd.
InventorsOsamu Tanaka, Toshio Kusumi, Yoshiyuki Shibuya, Takeshi Tano
Life of this patent
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Abstract
A filter medium which has an average pore diameter of more than 0.5 μm, a pressure loss of 2-50 mmH2O determined when air is permeated therethrough at a velocity of flow of 5.3 cm/sec, and a PF value of 18-12, which is calculated in accordance with the following equation on the basis of this pressure loss and a collection efficiency using DOP of a grain size of 0.10-0.12 μm. PF value = - log ( permeability ( % ) / 100 ) Pressure Loss × 100. Permeability (%)=100 −Collection Efficiency (%).
Claims14
A filter medium comprising a polytetrafluoroethylene porous membrane, wherein an average pore diameter of the polytetrafluoroethylene porous membrane is more than 0.5 μm and exhibits a pressure loss when air is passed through the medium at a flow velocity of 5.3 cm/sec is from 2 to 50 mmH2O, and a PF value calculated from the pressure loss and a collection efficiency using dioctylphthalate of a particle size of 0.10 to 0.12 μm according to an equation (1) below is between 18 and 22 (Equation (1) PF value = - log ( permeability ( % ) / 100 ) Pressure Loss × 100
- Permeability (%)=100−Collection Efficiency (%).
Dependencies are inferred from the claim text.