Patent US4728349A successfully refreshed from Google Patents.
US4728349A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air filter medium
Assignee: Individual
•
Filing: 1985-03-22
•
Granted: 1988-03-01
•
Expires: 2005-03-22
Abstract
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.
Inventors
- 👤 Yoshimi Oshitari
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:39
CPC Classifications
B; B01; B01D; B01D46/00; B01D46/52; B01D46/521; B01D46/523; B01D39/00; B01D39/14; B01D39/20; B01D39/2003; B01D39/2017; B01D46/10; B01D2275/00; B01D2275/10; Y; Y10; Y10S; Y10S55/00; Y10S55/05
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
118 words
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 μm 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 μm 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.
Claim 2
Dependent Claim
118 words
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 μm 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 μm 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.
Claim 3
Dependent Claim
20 words
An air filter medium according to claim 1, in which said supporting fiber layer is formed by large-diameter polypropylene fibers.
Claim 4
Dependent Claim
56 words
An air filter medium according to claim 1, in which the supporting fiber layer is comprised of polypropylene fibers of about 2 to 5 microns in diameter, and in which the dust-collecting layer is comprised of glass fibers of an average diameter of about 0.2 to 0.29 microns formed by paper-making on said supporting fiber layer.
References Cited (Backward Citations)
GB1018503A
Cited
US3208205A
Cited
US3258900A
Cited
US3262578A
Cited
US3490211A
Cited
US3505794A
Cited
US4011067A
Cited
US3986851A
Cited
US4188197A
Cited
US4102785A
Cited
DE2718581A1
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-03-01 | 1991-08-31 | 1992-03-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-01 | 1995-08-31 | 1996-03-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-01 | 1999-08-31 | 2000-03-01 | $7700.00 | Window Closed / Lapsed |