US4859340A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter sheet
Assignee: 3M Purification Inc
•
Filing: 1988-04-21
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Granted: 1989-08-22
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Expires: 2008-04-21
Abstract
Abstract A filter media sheet comprising fine particulate and a self-bonding matrix of cellulose fiber, the surfaces of at least one of which are modified with a polyamido-polyamine epichlorhydrin cationic resin, the matrix incorporating beaten cellulose fiber to provide a Canadian Standard Freeness of less than 600 ml.
Inventors
- 👤 Kenneth C. Hou
- 👤 Eugene A. Ostreicher
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 19:16
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/28; B01J20/28014; B01J20/28033; B01D; B01D39/00; B01D39/14; B01D39/16; B01D39/18; B01D39/20; B01D39/2068; B01D39/2072; B01J20/28028; D; D21; D21H; D21H11/00; D21H11/16; D21H11/20; D21H11/22; D21H27/00; D21H27/08
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
68 words
A filter medium sheet having enhanced capture potential for electronegative submicron particulate contaminants in a contaminated liquid passed therethrough, comprising at least about 50% by weight of siliceous particulate and a self bonding matrix of cellulose fiber, the surfaces of at least the particulate being modified with a sufficient amount of polyamido-polyamine epichlorhydrin cationic resin to impart a positive zeta potential to the surface of the filter media.
Claim 2
Dependent Claim
68 words
A filter medium sheet having enhanced capture potential for electronegative submicron particulate contaminants in a contaminated liquid passed therethrough, comprising at least about 50% by weight of siliceous particulate and a self bonding matrix of cellulose fiber, the surfaces of at least the particulate being modified with a sufficient amount of polyamido-polyamine epichlorhydrin cationic resin to impart a positive zeta potential to the surface of the filter media.
Claim 3
Dependent Claim
24 words
The filter medium of claim 1, wherein the amount of cationic resin is from about 1% to about 3% by weight of the medium.
Claim 4
Dependent Claim
28 words
The filter medium of claim 1, wherein the matrix incorporates sufficient beaten cellulose fiber to provide a matrix having a Canadian standard freeness of less than 600 mL.
Claim 5
Dependent Claim
22 words
The filter medium of claim 3, wherein the matrix comprises beaten pulp having a Canadian standard freeness of 100 to 500 mL.
Claim 6
Dependent Claim
23 words
The filter medium sheet of claim 3, wherein the matrix comprises beaten pulp having a Canadian standard freeness of 100 to 300 mL.
Claim 7
Dependent Claim
13 words
The filter medium of claim 1, wherein the siliceous particulate is diatomaceous earth.
Claim 8
Dependent Claim
18 words
The filter medium of claim 1, wherein the siliceous particulate comprises an admixture of diatomaceous earth and perlite.
Claim 9
Dependent Claim
19 words
The filter medium of claim 1, wherein the siliceous particulate exhibits a diameter of less than about 10 microns.
Claim 10
Dependent Claim
28 words
The filter medium of claim 1, wherein the matrix incorporates sufficient beaten cellulose fiber to provide a matrix having a Canadian standard freeness of less than 300 mL.
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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) | 1992-08-21 | 1993-02-20 | 1993-08-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-08-21 | 1997-02-20 | 1997-08-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-08-21 | 2001-02-20 | 2001-08-22 | $7700.00 | Window Closed / Lapsed |