US3724673A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Textured membranes for blood dialyzers oxygenators and the like
Assignee: General Electric Co
•
Filing: 1970-08-28
•
Granted: 1973-04-03
•
Expires: 1990-08-28
Abstract
Abstract A myriad of small undulations or projections are formed permanently in a thin membrane to give it a textured surface. The membrane may be permselective for use in fluid exchange devices such as blood oxygenators and artificial kidneys or dialyzers. When such membranes are superposed on each other, a thin film of blood or other fluid flowing between them is gently agitated by the textured surface to enhance the absorption of a gas such as oxygen which is transported through the membrane. The textured surface prevents adjacent membrane layers from adhering. The textured surface is created by heating, vacuum forming and cooling on a suitable die.
Inventors
- 👤 D Ryon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 20:57
CPC Classifications
B; B01; B01D; B01D71/00; B01D71/06; B01D71/76; B01D71/80; B01D71/50; B01D71/70; B01D2325/00; B01D2325/06
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
41 words
The membrane defined in claim 1 wherein: a. the film deformations constitute crest and valley regions which are mutually confluent with each other, said crest regions being the thinner parts and said valley regions being the thicker parts of said film.
Claim 2
Dependent Claim
18 words
The invention defined in claim 1 wherein: a. said membrane consists of an organopolysiloxane polycarbonate block copolymer material.
Claim 3
Dependent Claim
23 words
The invention defined in claim 1 wherein: a. the distance between the centers of the crest and valley regions is about 42 mils.
Claim 4
Dependent Claim
28 words
The invention defined in claim 1 wherein: a. the distance between the top of said crest regions and the bottom of the valley regions is about 10 mils.
Claim 5
Independent Claim
140 words
A method of texturing a thin thermoplastic membrane comprising the steps of: a. sealing a thermoplastic membrane with one of its surfaces exposed to a space for gas and another confronting an imperforate forming die which has a myriad of uniformly spaced apart open regions presented toward the membrane, b. establishing a pressure difference between gas in said space and the space between the die and the confronting membrane while heating it so that ambient gas pressure distends regions of the membrane thermoplastically into the open regions of the die until at least a part of said distended regions is thinner than the original membrane, and then c. discontinuing the application of heat and cooling the membrane for an interval followed by discontinuing said pressure difference, whereupon plastic deformations in the membrane formed in the open regions are permanently set.
Claim 6
Dependent Claim
35 words
The method set forth in claim 6 as specifically applied to texturing a membrane consisting of organopolysiloxane polycarbonate block copolymer in which: a. said membrane is heated to a temperature in the vicinity of 140*F.
Claim 7
Dependent Claim
29 words
The method set forth in claim 6 wherein: a. the forming die used has its spaced apart open regions defined by laterally spaced apart cones projecting toward the membrane.
Claim 8
Dependent Claim
98 words
A thin textured membrane for use in fluid exchange devices such as blood oxygenators and dialyzers, comprising: a. a film comprised of thermoplastic material having a substantially uniform original thickness an having a myriad of adjacent thermoplastically formed deformations which constitute projections in respect to one side of said film and which constitute recesses corresponding with the projections, respectively, with respect to the other side of said film, the film between said deformations being closer to said original thickness and the film defining said deformations individually having at least a part which is thinner than said original thickness.
References Cited (Backward Citations)
US3026231A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-02 | 1976-10-02 | 1977-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-02 | 1980-10-02 | 1981-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-02 | 1984-10-02 | 1985-04-03 | $7700.00 | Window Closed / Lapsed |