Patent US5354469A successfully refreshed from Google Patents.
US5354469A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Layered plasma polymer composite membranes
Assignee: Bend Research Inc
•
Filing: 1993-06-14
•
Granted: 1994-10-11
•
Expires: 2013-06-14
Abstract
Abstract Layered plasma polymer composite fluid separation membranes are disclosed, which comprise alternating selective and permeable layers for a total of at least 2n layers, where n is ≧2 and is the number of selective layers.
Inventors
- 👤 Walter C. Babcock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 09:15
CPC Classifications
B; B01; B01D; B01D53/00; B01D53/22; B01D53/228; B01D69/00; B01D69/12; B01D69/125; B01D69/127
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
106 words
A laminated permselective membrane comprising alternating selective and permeable layers on a support membrane, said permeable layers having a permeability of at least twice the permeability of each adjacent selective layer, said selective layer having a selectivity of at least 50% greater than the selectivity of the adjacent permeable layer, at least 2n layers where n is ≧2 and is the number of selective layers, the thickness of each layer is less than 5 microns, the selective layers are prepared by plasma polymerization, and wherein the cumulative resistance of said selective layers is greater than or equal to 50% of the overall membrane resistance to permeation.
Claim 2
Dependent Claim
106 words
A laminated permselective membrane comprising alternating selective and permeable layers on a support membrane, said permeable layers having a permeability of at least twice the permeability of each adjacent selective layer, said selective layer having a selectivity of at least 50% greater than the selectivity of the adjacent permeable layer, at least 2n layers where n is ≧2 and is the number of selective layers, the thickness of each layer is less than 5 microns, the selective layers are prepared by plasma polymerization, and wherein the cumulative resistance of said selective layers is greater than or equal to 50% of the overall membrane resistance to permeation.
Claim 3
Dependent Claim
19 words
The membrane of claim 1 wherein the thickness of each of said layers is between 0.005 and 2 microns.
Claim 4
Dependent Claim
15 words
The membrane of claim 1 wherein a permeable layer is immediately adjacent said support membrane.
Claim 5
Dependent Claim
43 words
The membrane of claim 3 wherein said support membrane has a thickness less than 1000 microns, an effective surface pore diameter of less than 0.2 micron, and a pressure-normalized flux of greater than 10 times the pressure-normalized flux of all of said layers.
Claim 6
Dependent Claim
16 words
The membrane of claim 1 wherein each of said permeable layers are prepared by plasma polymerization.
Claim 7
Dependent Claim
25 words
The membrane of claim 5 wherein each of said selective layers is prepared from vinyltrimethylsilane and each of said permeable layers is prepared from hexamethyldisiloxane.
Claim 8
Dependent Claim
19 words
The membrane of claim 1 wherein each of said selective layers has a permeability of less than 1 barrer.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-10-10 | 1998-04-11 | 1998-10-11 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-10-10 | 2002-04-11 | 2002-10-11 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-10-10 | 2006-04-11 | 2006-10-11 | $7700.00 | Window Closed / Lapsed |