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US 4,728,349 AGranted
Air filter medium
OwnerYoshimi Oshitariinventor
Life of this patent
Estimating the term…
Abstract
An air filter medium, in which a dust-collecting layer of glass fibers of a diameter necessary for obtaining a desired dust-collecting efficiency is formed on a supporting fiber layer of low dust-collecting efficiency and low pressure drop to a sufficient thickness to obtain a desired dust-collecting efficiency and a desired pressure drop of the air filter medium.
Claims3
An air filter medium comprising:
- a supporting fiber layer made of polypropylene fibers and of low dust-collecting efficiency for particles having a diameter less than 0.3 .mu.m and low pressure drop;
- and
- a dust-collecting layer of glass fibers of a diameter necessary for obtaining a desired dust-collecting efficiency formed on said supporting fiber layer to a thickness less than one third the thickness of said supporting fiber layer and sufficiently thick to obtain a dust-collecting efficiency of 99.9999% for 0.1 to 0.12 .mu.m diameter particles and a pressure drop of 10 mm to 23 mm of water at an air flow velocity of 2.5 cm/sec, and said air filter medium having a total thickness less than 0.4 mm.
Dependencies are inferred from the claim text.