Patent US4261072A successfully refreshed from Google Patents.
Patent US224785A successfully refreshed from Google Patents.
Patent US2928765A successfully refreshed from Google Patents.
US2928765A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Air filter paper and method of making same
Assignee: C H Dexter & Sons Inc
•
Filing: 1957-02-11
•
Granted: 1960-03-15
•
Expires: 1977-02-11
Abstract
No abstract record available.
Inventors
- 👤 Homer L Kurjan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 14:16
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/18; D; D21; D21F; D21F11/00; D21F11/02; D21F11/04; D21F11/14
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
107 words
A METHOD OF FORMING A WATER-LAID HIGHLY PERMEABLE MULTIPHASE PAPER SHEET SUITABLE FOR USE AS AN AIR FILTERING MEDIUM COMPRISING THE STEPS OF FLOWING A DILUTE SLURRY OF UNBEATEN REDWOOD BARK FIBERS ONTO A TRAVELLING WIRE SCREEN TO FORM A BASE LAYER OF SUCH FIBERS, IMMEDIATELY THEREAFTER FLOWING A DILUTE SLURRY OF ORDINARY PAPER MAKING FIBERS OVER THE REDWOOD BARK FIBERS TO FORM A COHESIVE TOP LAYER OF THE PAPER MAKING FIBERS, AND DRYING THE RESULTING WEB WHILE MAINTAINING THE WEB IN UNCOMPACTED FORM TO PRODUCE A FLEXIBLE SELF-SUSTAINING SHEET HAVING RELATIVELY LOOSE REDWOOD BARK FIBERS ON ONE SIDE AND A PAPER BONDING LAYER ON THE OTHER.
Claim 2
Independent Claim
107 words
A METHOD OF FORMING A WATER-LAID HIGHLY PERMEABLE MULTIPHASE PAPER SHEET SUITABLE FOR USE AS AN AIR FILTERING MEDIUM COMPRISING THE STEPS OF FLOWING A DILUTE SLURRY OF UNBEATEN REDWOOD BARK FIBERS ONTO A TRAVELLING WIRE SCREEN TO FORM A BASE LAYER OF SUCH FIBERS, IMMEDIATELY THEREAFTER FLOWING A DILUTE SLURRY OF ORDINARY PAPER MAKING FIBERS OVER THE REDWOOD BARK FIBERS TO FORM A COHESIVE TOP LAYER OF THE PAPER MAKING FIBERS, AND DRYING THE RESULTING WEB WHILE MAINTAINING THE WEB IN UNCOMPACTED FORM TO PRODUCE A FLEXIBLE SELF-SUSTAINING SHEET HAVING RELATIVELY LOOSE REDWOOD BARK FIBERS ON ONE SIDE AND A PAPER BONDING LAYER ON THE OTHER.
References Cited (Backward Citations)
US1468036A
Cited
US1349112A
Cited
US1828028A
Cited
US1860097A
Cited
US2108231A
Cited
US2098733A
Cited
US2414833A
Cited
US2531504A
Cited
US2664964A
Cited
US2683400A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1963-03-15 | 1963-09-14 | 1964-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1967-03-15 | 1967-09-14 | 1968-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1971-03-15 | 1971-09-14 | 1972-03-15 | $7700.00 | Window Closed / Lapsed |