Patent US4094775A successfully refreshed from Google Patents.
US4094775A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dialysis system
Assignee: California Institute of Technology
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Filing: 1977-02-28
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Granted: 1978-06-13
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Expires: 1997-02-28
Abstract
Abstract The improved hemodialysis system utilizes a second polymeric membrane having dialyzate in contact with one surface and a urea decomposition solution in contact with the other surface. The membrane selectively passes urea from the dialyzate into the decomposition solution, while preventing passage of positively charged metal ions from the dialyzate into the solution and ammonium ions from the solution into the dialyzate.
Inventors
- 👤 William A. Mueller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 05:21
CPC Classifications
A; A61; A61M; A61M1/00; A61M1/14; A61M1/16; A61M1/1694; A61M1/1696; B; B01; B01D; B01D61/00; B01D61/24; B01D61/28; B01D71/00; B01D71/06; B01D71/26; B01D71/261; B01D71/76; B01D71/78
Claims Analysis
Total Claims: 22
Claim 1
Independent Claim
112 words
A system for selectively removing urea from an aqueous liquid containing urea and positive metal cations comprising in combination: a container divided into a first chamber and a second chamber by means of a continuous sheet of cationically charged polymeric membrane selectively permeable to urea and having low permeability to cations; said first chamber including means for receiving said liquid; and said second chamber receiving a solution containing a urea decomposition agent whereby said cations are repelled by said membrane and retained in said liquid and urea permeates through the membrane into the solution and is decomposed into bicarbonate and ammonium, the ammonium being retained in the solution in the second chamber.
Claim 2
Independent Claim
112 words
A system for selectively removing urea from an aqueous liquid containing urea and positive metal cations comprising in combination: a container divided into a first chamber and a second chamber by means of a continuous sheet of cationically charged polymeric membrane selectively permeable to urea and having low permeability to cations; said first chamber including means for receiving said liquid; and said second chamber receiving a solution containing a urea decomposition agent whereby said cations are repelled by said membrane and retained in said liquid and urea permeates through the membrane into the solution and is decomposed into bicarbonate and ammonium, the ammonium being retained in the solution in the second chamber.
Claim 3
Dependent Claim
14 words
A system according to claim 1 in which the membrane contains quaternary ammonium groups.
Claim 4
Dependent Claim
16 words
A system according to claim 2 in which the membrane is a vinyl pyridine grafted polyethylene.
Claim 5
Dependent Claim
18 words
A system according to claim 1 in which the membrane has a thickness from 1 to 15 mils.
Claim 6
Dependent Claim
19 words
A system according to claim 4 in which the membrane has an exchange capacity of 1 to 20 meq/gm.
Claim 7
Dependent Claim
39 words
A system according to claim 1 in which the first chamber is a hollow body having said membrane as one wall thereof and having an inlet and outlet for flowing said liquid past a first surface of the membrane.
Claim 8
Dependent Claim
14 words
A system according to claim 1 in which the urea decomposition agent is urease.
Claim 9
Dependent Claim
27 words
A system according to claim 7 in which the urease concentration of the solution is at least 25% by weight of the urea content of the liquid.
Claim 10
Dependent Claim
43 words
A system according to claim 7 in which the liquid is dialyzate containing urea and further including a blood dialysis membrane selectively permeable to urea having one surface in contact with said dialyzate and a second surface for contacting a flow of blood.
Claim 11
Independent Claim
104 words
A method of selectively removing urea from an aqueous liquid containing urea and positive metal cations comprising the steps of: placing the liquid in contact with a first surface of a cationically charged polymeric membrane selectively permeable to urea and having low permeability to cations; placing an urea decomposition solution containing an urea decomposition agent in contact with a second surface of the membrane; and selectively permeating urea from the liquid through the membrane into the solution thereby decomposing urea into ammonium cations and bicarbonate whereby the ammonium cations are retained in the decomposition solution and the metal cations are retained in the liquid.
Claim 12
Independent Claim
104 words
A method of selectively removing urea from an aqueous liquid containing urea and positive metal cations comprising the steps of: placing the liquid in contact with a first surface of a cationically charged polymeric membrane selectively permeable to urea and having low permeability to cations; placing an urea decomposition solution containing an urea decomposition agent in contact with a second surface of the membrane; and selectively permeating urea from the liquid through the membrane into the solution thereby decomposing urea into ammonium cations and bicarbonate whereby the ammonium cations are retained in the decomposition solution and the metal cations are retained in the liquid.
Claim 13
Dependent Claim
14 words
A method according to claim 10 in which the membrane contains quaternary ammonium groups.
Claim 14
Dependent Claim
20 words
A method according to claim 11 in which the membrane has an exchange capacity of from 1 to 20 meq/gm.
Claim 15
Dependent Claim
24 words
A method according to claim 12 in which the membrane is a vinyl pyridine grafted polyethylene having a thickness from 1 to 15 mils.
Claim 16
Dependent Claim
12 words
A method according to claim 11 in which the agent is urease.
Claim 17
Dependent Claim
29 words
A method according to claim 14 in which the urease concentration of the decomposition solution is at least 25% of the concentration of urea in the urea containing liquid.
Claim 18
Dependent Claim
19 words
A method according to claim 14 in which the urea containing liquid is dialyzate from a blood dialysis unit.
Claim 19
Dependent Claim
14 words
A method according to claim 14 in which the urea containing liquid is blood.
Claim 20
Dependent Claim
88 words
An artificial kidney machine comprising in combination: enclosure means having an inlet and an outlet, and having a wall surface formed of a cationically charged membrane defining a channel for flowing urea containing blood past one surface of the membrane; urea removal means comprising walls defining a chamber, said chamber including a solution of urease having a concentration at least 25% by weight of the urea content of the blood; and means for supplying the urea permeate from the second surface of the membrane to the urease solution.
Claim 21
Dependent Claim
88 words
An artificial kidney machine comprising in combination: enclosure means having an inlet and an outlet, and having a wall surface formed of a cationically charged membrane defining a channel for flowing urea containing blood past one surface of the membrane; urea removal means comprising walls defining a chamber, said chamber including a solution of urease having a concentration at least 25% by weight of the urea content of the blood; and means for supplying the urea permeate from the second surface of the membrane to the urease solution.
Claim 22
Dependent Claim
20 words
A machine according to claim 18 in which the membrane forms a common wall portion of said channel and chamber.
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) | 1981-06-12 | 1981-12-12 | 1982-06-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-06-12 | 1985-12-12 | 1986-06-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-06-12 | 1989-12-12 | 1990-06-13 | $7700.00 | Window Closed / Lapsed |