Patent US4731135A successfully refreshed from Google Patents.
US4731135A
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Process for making a filter having a continuous density gradient
Assignee: Denso Corp
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Filing: 1986-03-04
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Granted: 1988-03-15
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Expires: 2006-03-04
Abstract
Abstract A filter for removing dusts from fluids, which comprises fibers bonded each other with a binder and/or hot-pressed, having a fiber density of 0.01 to 0.1 at the side of inflow of fluid to be treated and a fiber density of 0.05 to 0.5 at the side of outflow of the fluid with a continuous fiber density gradient and having a uniform distribution of fiber material in direction of thickness, and a process for the production thereof. The filter is particularly useful as an air filter for automobiles or air conditioner.
Inventors
- 👤 Yatsuhiro Tani
- 👤 Susumu Ohmori
- 👤 Hideki Komagata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:25
CPC Classifications
D; D04; D04H; D04H1/00; D04H1/70; D04H1/72; B; B01; B01D; B01D46/00; B01D46/10; D04H1/40; D04H1/42; D04H1/4326; D04H1/435; D04H1/58; D04H1/60; F; F02; F02M; F02M35/00; F02M35/02; F02M35/024; B01D2239/00; B01D2239/02; B01D2239/0216; B01D2239/0233; B01D2239/04; B01D2239/0471; B01D2239/06; B01D2239/0604; B01D2239/0618; B01D2239/064; B01D2239/065; B01D2239/069; B01D2239/0695; B01D2239/08; B01D2239/086; B01D2239/12; B01D2239/1233; B01D2239/1241; B01D2239/1291; Y; Y10; Y10S; Y10S55/00; Y10S55/05
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
187 words
A process for the production of a filter having an inlet side and an outlet side and comprising fibers bonded to each other with a binder, said filter having a fiber density of 0.01 to 0.1 at the inlet side and a fiber density of 0.05 to 0.5 at the outlet side and having a continuous fiber density gradient from the inlet side to the outlet side while having a uniform distribution of the different types of fibers, comprising the steps of: drawing a gas, containing a powdery binder having a particles size of 1 to 150μ, by suction through webs having a fiber density of 7×10 -4 to 1×10 -2 at a flow rate of not more than 4 m/second, thereby adhering the binder to the fibers of the webs in an amount of 10 to 80% by weight to the total weight of webs so that the adhered amount of the binder is rich at the inlet side and is poor at the outlet side; hot-pressing the binder-containing webs at a fiber density of not higher than 0.2; and recovering the webs from the pressing.
Claim 2
Dependent Claim
187 words
A process for the production of a filter having an inlet side and an outlet side and comprising fibers bonded to each other with a binder, said filter having a fiber density of 0.01 to 0.1 at the inlet side and a fiber density of 0.05 to 0.5 at the outlet side and having a continuous fiber density gradient from the inlet side to the outlet side while having a uniform distribution of the different types of fibers, comprising the steps of: drawing a gas, containing a powdery binder having a particles size of 1 to 150μ, by suction through webs having a fiber density of 7×10 -4 to 1×10 -2 at a flow rate of not more than 4 m/second, thereby adhering the binder to the fibers of the webs in an amount of 10 to 80% by weight to the total weight of webs so that the adhered amount of the binder is rich at the inlet side and is poor at the outlet side; hot-pressing the binder-containing webs at a fiber density of not higher than 0.2; and recovering the webs from the pressing.
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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) | 1991-03-15 | 1991-09-14 | 1992-03-15 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-03-15 | 1995-09-14 | 1996-03-15 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-03-15 | 1999-09-14 | 2000-03-15 | $7700.00 | Window Closed / Lapsed |