Patent US3680709A successfully refreshed from Google Patents.
US3680709A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cartridge type filter and method of making same
Assignee: Individual
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Filing: 1970-11-18
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Granted: 1972-08-01
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Expires: 1990-11-18
Abstract
Abstract A cartridge type filter having a rigid tubular perforated core and a porous web of spunbonded fibrous resin wound thereon. The density of the wound web is controlled by control of tension on the web during winding. End portions of the winding are fused to be impervious.
Inventors
- 👤 Charles L Snow
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:08
CPC Classifications
B; B01; B01D; B01D29/00; B01D29/11; B01D29/111; B01D29/13; B01D29/15; B01D29/21; B01D29/216; B01D2201/00; B01D2201/18; B01D2201/182
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
47 words
A cartridge type filter which comprises a rigid tubular perforated core and a winding thereon including a plurality of convolutions of a fibrous spunbonded thermoplastic resin sheet material surrounding the core, edge portions of the windings being fused together to form impervious end portions on the filter.
Claim 2
Dependent Claim
47 words
A cartridge type filter which comprises a rigid tubular perforated core and a winding thereon including a plurality of convolutions of a fibrous spunbonded thermoplastic resin sheet material surrounding the core, edge portions of the windings being fused together to form impervious end portions on the filter.
Claim 3
Independent Claim
82 words
A method of forming a cartridge type filter which comprises winding an elongated web of fibrous spunbonded thermoplastic resin sheet material on a rigid tubular perforated core while controlling the tension on the web during winding to provide a predetermined density in the wound web and, following winding, heating edge portions of the wound web to fuse the resin fibers along opposite side edges of the web to provide impervious end portions on the filter formed of fused material of the web.
Claim 4
Independent Claim
82 words
A method of forming a cartridge type filter which comprises winding an elongated web of fibrous spunbonded thermoplastic resin sheet material on a rigid tubular perforated core while controlling the tension on the web during winding to provide a predetermined density in the wound web and, following winding, heating edge portions of the wound web to fuse the resin fibers along opposite side edges of the web to provide impervious end portions on the filter formed of fused material of the web.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-01 | 1976-01-31 | 1976-08-01 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-01 | 1980-01-31 | 1980-08-01 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-01 | 1984-01-31 | 1984-08-01 | $7700.00 | Window Closed / Lapsed |