US3690852A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of producing graded fibrous filter media
Assignee: Owens Corning
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Filing: 1969-12-29
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Granted: 1972-09-12
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Expires: 1989-12-29
Abstract
Abstract A PROCESS FOR PRODUCING A GRADING FIBROUS FILTER MEDIA PREFORMED IN A MAT BY INTERMINGLING MINERAL FIBERS OF ONE AVERAGE DIAMETER WITH FIBERS OF SMALLERS AVERAGE DIAMETER IN THE AREA OF A PLANE PARALLEL WITH A MAJOR FACE OF THE MAT. TWO GROUPS OF FIBERS OF DIFFERENT DIAMETER ARE ATTENUATED AND BLOWN HORIZONTALLY UPON A MOVING CONVEYOR SUCH THAT THE GROUPS INTERMINGLE WITH EACH OTHER TO A LIMITED EXTENT PRIOR TO DEPOSITION ON THE CONVEYOR TO PRODUCE A TWO LAYER, GRADED DENSITY PRODUCT HAVING A GRADUAL TRANSITION BETWEEN FIBER LAYERS.
Inventors
- 👤 Irving N Smith
- 👤 Jack R Pfeffer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 16:18
CPC Classifications
D; D04; D04H; D04H1/00; B; B01; B01D; B01D39/00; B01D39/14; B01D39/20; B01D39/2003; B01D39/2017; B01D39/2024
Claims Analysis
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References Cited (Backward Citations)
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-12 | 1976-03-13 | 1976-09-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-12 | 1980-03-13 | 1980-09-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-12 | 1984-03-13 | 1984-09-12 | $7700.00 | Window Closed / Lapsed |