US4366068A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Filter and method of making same
Assignee: Specialty Materials Inc
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Filing: 1981-06-23
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Granted: 1982-12-28
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Expires: 2001-06-23
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 cationic colloidal silica.
Inventors
- 👤 Eugene A. Ostreicher
- 👤 Kenneth C. Hou
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 17:41
CPC Classifications
B; B01; B01J; B01J20/00; B01J20/28; B01J20/28014; B01J20/28033; B01D; B01D39/00; B01D39/08; B01D39/083; 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; B01D2239/00; B01D2239/04; B01D2239/0407; B01D2239/0414; B01D2239/0471; B01D2239/0485; B01D2239/12; B01D2239/1233; B01D2239/1241
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
123 words
A method for the removal of submicron contaminants from biological liquid comprising passing the contaminated liquid through a filter media sheet consisting essentially of fine particulate and self-bonding matrix of cellulose fiber, the surfaces of at least one of which are modified with a sufficient amount of an inorganic cationic colloidal silica to provide a positive zeta potential to the surface of the filter media sheet, wherein the cationic colloidal silica is derived from a dispersion of positively charged colloidal particles having a dense silica core modified with a polyvalent metal-oxygen compound wherein the polyvalent metal is aluminum, and a sufficient amount of the compound is provided to coat the silica to a level of at least 13% by weight of colloidal solids.
Claim 2
Independent Claim
123 words
A method for the removal of submicron contaminants from biological liquid comprising passing the contaminated liquid through a filter media sheet consisting essentially of fine particulate and self-bonding matrix of cellulose fiber, the surfaces of at least one of which are modified with a sufficient amount of an inorganic cationic colloidal silica to provide a positive zeta potential to the surface of the filter media sheet, wherein the cationic colloidal silica is derived from a dispersion of positively charged colloidal particles having a dense silica core modified with a polyvalent metal-oxygen compound wherein the polyvalent metal is aluminum, and a sufficient amount of the compound is provided to coat the silica to a level of at least 13% by weight of colloidal solids.
Claim 3
Dependent Claim
23 words
The method of claim 1, wherein the matrix incorporates beaten cellulose fiber to provide a Canadian Standard Freeness of less than 600 ml.
Claim 4
Dependent Claim
25 words
The method of claim 1, comprising cationic colloidal silica to provide a positive zeta potential to at least one of said fiber and said particulate.
Claim 5
Dependent Claim
17 words
The method of claim 1, comprising from about 3% to about 6% by weight cationic colloidal silica.
Claim 6
Dependent Claim
19 words
The method of claim 1, wherein the silica dispersion comprises at least 15% alumina by weight of colloidal solids.
Claim 7
Dependent Claim
18 words
The method of claim 1, wherein the fine particulate comprises at least 50% by weight of diatomaceous earth.
Claim 8
Dependent Claim
17 words
The method of claim 1, wherein the fine particulate comprises an admixture of diatomaceous earth and perlite.
Claim 9
Dependent Claim
20 words
The method of claim 1, wherein the fine particulate exhibits an average particulate dimension of less than about 10 microns.
Claim 10
Dependent Claim
13 words
The method of claim 1, wherein the filter sheet is sanitized or sterilized.
Claim 11
Dependent Claim
11 words
The method of claim 9, wherein the filter sheet is autoclaved.
Claim 12
Dependent Claim
13 words
The method of claim 9, wherein the filter sheet is hot water flushed.
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) | 1985-12-27 | 1986-06-28 | 1986-12-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-27 | 1990-06-28 | 1990-12-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-27 | 1994-06-28 | 1994-12-28 | $7700.00 | Window Closed / Lapsed |