US4824451A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Melt-blown filter medium
Assignee: Kimberly Clark Worldwide Inc
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Filing: 1987-09-21
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Granted: 1989-04-25
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Expires: 2007-09-21
Abstract
Abstract HEPA or pre-HEPA filter media are made by forming a web of melt-blown polypropylene fibers. The melt-blown process is accomplished at a low through-put of about 1 pound per inch of die width per hour and at a high fluid flow rate of about 250 to 325 standard cubic feet per minute. The resulting web has fibers with an average diameter of about 5 microns and surface pores of less than 30 microns in size. By cold calendering the web with pressure of between 100 and 300 psi, further filter efficiency can be achieved. The resulting calendered web has surface pore sizes less than 20 microns.
Inventors
- 👤 Clifford M. Vogt
- 👤 Peter W. Shipp, Jr.
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:18
CPC Classifications
B; B01; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/1607; B01D39/1623; B01D39/163; D; D04; D04H; D04H1/00; D04H1/40; D04H1/54; D04H1/56; B01D2239/00; B01D2239/10
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
75 words
A filter medium having an efficiency in the range of from about 97.0 to about 99.57 percent with a pressure drop in the range of from about 0.32 to 0.65 inch of water comprising a cold calendered web of meltblown polypropylene fibers, wherein the fibers have an average diameter of about 5 microns, and wherein the fibers are randomly oriented and spaced to define surface pores which are less than about 20 microns in size.
Claim 2
Dependent Claim
75 words
A filter medium having an efficiency in the range of from about 97.0 to about 99.57 percent with a pressure drop in the range of from about 0.32 to 0.65 inch of water comprising a cold calendered web of meltblown polypropylene fibers, wherein the fibers have an average diameter of about 5 microns, and wherein the fibers are randomly oriented and spaced to define surface pores which are less than about 20 microns in size.
References Cited (Backward Citations)
US2988469A
Cited
US3231639A
Cited
US3849241A
Cited
US3755527A
Cited
US3972759A
Cited
US3825380A
Cited
US4018646A
Cited
US3888610A
Cited
US4032688A
Cited
US4011067A
Cited
US4100324A
Cited
US4181513A
Cited
US4116738A
Cited
US4215682A
Cited
US4211661A
Cited
US4375718A
Cited
US4431545A
Cited
US4526733A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-04-24 | 1992-10-24 | 1993-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-04-24 | 1996-10-24 | 1997-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-04-24 | 2000-10-24 | 2001-04-25 | $7700.00 | Window Closed / Lapsed |