US3850762A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process for producing an anodic aluminum oxide membrane
Assignee: Boeing Co
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Filing: 1973-08-13
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Granted: 1974-11-26
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Expires: 1993-08-13
Abstract
Abstract The present invention discloses a novel method for manufacturing porous membranes for hyperfiltration and ultrafiltration by the process of anodizing aluminum to form a layer of porous aluminum oxide, closing the pores thus formed as necessary to achieve the desired pore diameter, and removing the aluminum and barrier layer of aluminum oxide by etching to leave only the desired membrane remaining.
Inventors
- 👤 A Smith
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:04
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/02; B01D71/024; B01D71/025; B01D61/00; B01D61/14; B01D61/145; B01D67/00; B01D67/0039; B01D67/0053; B01D67/006; B01D67/0065
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
88 words
THE METHOD OF MAKING A POROUS MEMBRANE FOR WATER DESALINATION COMPRISING THE STEPS OF: A. FORMING AN OXIDE COATING ON A SHEET OF ALUMINUM IN AN ANODIZING SOLUTION WHICH PRODUCES AN OXIDE, SAID OXIDE COMPRISING A GENERALLY POROUS LAYER AND A NON-POROUS LAYER; B. REMOVING ANY OF SAID SHEET OF ALUMINUM REMAINING AFTER SAID ANODIZATION OF SAID SHEET OF ALUMINUM; C. REMOVING SAID NON-POROUS LAYER OF OXIDE; AND, D. TREATING SAID GENERALLY POROUS LAYER SO THAT IS ALLOWS THE FLOW OF WATER BUT RESTRICTS THE FLOW OF SALTS.
Claim 2
Independent Claim
88 words
THE METHOD OF MAKING A POROUS MEMBRANE FOR WATER DESALINATION COMPRISING THE STEPS OF: A. FORMING AN OXIDE COATING ON A SHEET OF ALUMINUM IN AN ANODIZING SOLUTION WHICH PRODUCES AN OXIDE, SAID OXIDE COMPRISING A GENERALLY POROUS LAYER AND A NON-POROUS LAYER; B. REMOVING ANY OF SAID SHEET OF ALUMINUM REMAINING AFTER SAID ANODIZATION OF SAID SHEET OF ALUMINUM; C. REMOVING SAID NON-POROUS LAYER OF OXIDE; AND, D. TREATING SAID GENERALLY POROUS LAYER SO THAT IS ALLOWS THE FLOW OF WATER BUT RESTRICTS THE FLOW OF SALTS.
Claim 3
Dependent Claim
55 words
The method of making a porous membrane for water desalination as claimed in claim 1 wherein: said generally porous layer is protected by the application of a buffered solution to said generally porous layer while said non-porous layer is removed by the application of a solution selected from the group consisting of acids and alkalines.
Claim 4
Dependent Claim
51 words
The method of making a porous membrane for water desalination as claimed in claim 1 wherein: said step of treating said generally porous layer so that it allows the flow of water but restricts the flow of salts is accomplished by the application of hot water to said generally porous layer.
Claim 5
Dependent Claim
65 words
The method of making a porous membrane for water desalination as claimed in claim 1 wherein: said step of treating said generally porous layer so that it allows the flow of water but restricts the flow of salts is accomplished by the simultaneous application of an alkaline solution to one side of said membrane and a buffered solution to the other side of said membrane.
Claim 6
Dependent Claim
82 words
The method of making a porous membrane for water desalination as claimed in claim 1 wherein: said steps of removing said non-porous layer of oxide and of treating said generally porous layer so that it allows the flow of water but restricts the flow of salts are accomplished at one time by the simultaneous application of an alkaline solution to the non-porous layer side of said oxide coating and a buffered solution to the generally porous layer side of said oxide coating.
References Cited (Backward Citations)
US2230868A
Cited
US2380505A
Cited
US3023149A
Cited
DE1131481B
Cited
US3322653A
Cited
FR1182379A
Cited
US3607680A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-11-25 | 1978-05-27 | 1978-11-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-25 | 1982-05-27 | 1982-11-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-25 | 1986-05-27 | 1986-11-26 | $7700.00 | Window Closed / Lapsed |