Patent US2017876A successfully refreshed from Google Patents.
Patent US4614577A successfully refreshed from Google Patents.
US4614577A
Expired / Lapsed
US
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Apparatus for urea analysis
Assignee: Siemens AG
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Filing: 1984-12-27
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Granted: 1986-09-30
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Expires: 2004-12-27
Abstract
Abstract For determining the urea concentration in liquids in continuous operation, with a high sensitivity and reliable determination of the urea content over an extended period of time, an electrode which is separated from the urea containing liquid by means of a diaphragm with a diffusion coefficient of less than 10 -7 cm 2 s -1 for urea has impressed on it potentiostatically and cyclically, two potential values, the more positive potential being between 0.9 and 2.0. V/H 2 rev, and the more negative potential being lower than 0.6 V/H 2 rev, and at the more positive potential, the current flowing within a predetermined time interval is evaluated as the measuring signal.
Inventors
- 👤 Konrad Mund
- 👤 Gunter Luft
- 👤 Ulrich Gebhardt
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:52
CPC Classifications
G; G01; G01N; G01N33/00; G01N33/48; G01N33/50; G01N33/53; G01N33/5302; G01N33/5304; G01N33/62
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
82 words
A urea sensor comprising: (a) a measuring electrode, (b) a counter electrode and a reference electrode, (c) a diaphragm with a diffusion coefficient for urea of less than 10 -7 cm 2 s -1 covering the measuring electrode, whereby during use said diaphram will be disposed between said measuring electrode and a urea containing liquid, said diaphragm having both hydrophobic and hydrophilic properties and having a degree of hydrophilization, H, which is in the interval of from about 1:15 to about 1:100.
Claim 2
Dependent Claim
82 words
A urea sensor comprising: (a) a measuring electrode, (b) a counter electrode and a reference electrode, (c) a diaphragm with a diffusion coefficient for urea of less than 10 -7 cm 2 s -1 covering the measuring electrode, whereby during use said diaphram will be disposed between said measuring electrode and a urea containing liquid, said diaphragm having both hydrophobic and hydrophilic properties and having a degree of hydrophilization, H, which is in the interval of from about 1:15 to about 1:100.
Claim 3
Dependent Claim
25 words
A urea sensor according to claim 1, wherein said diaphragm has a diffusion coefficient for urea of about 10 -11 cm 2 s -1 .
Claim 4
Dependent Claim
18 words
A urea sensor according to claim 1 or 2, wherein said diaphragm has a thickness of ≦10 μm.
Claim 5
Dependent Claim
21 words
A urea sensor according to claim 1, wherein the degree of hydrophilization H of the diaphragm is in the interval 1:30≧H≧1:60.
Claim 6
Dependent Claim
21 words
A urea sensor according to claim 1 or 4, wherein said diaphragm consists of weakly hydrophilized polysulfone, and preferably sulfonized polysulfone.
Claim 7
Dependent Claim
19 words
A urea sensor according to claim 1, wherein said measuring electrode consists of a noble metal, preferably of platinum.
Claim 8
Dependent Claim
20 words
A urea sensor according to claim 1, wherein said counter electrode at the same time acts as the reference electrode.
Claim 9
Dependent Claim
15 words
A urea sensor according to claim 7, wherein said counter electrode consists of vitreous carbon.
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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) | 1989-09-29 | 1990-03-31 | 1990-09-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-09-29 | 1994-03-31 | 1994-09-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-09-29 | 1998-03-31 | 1998-09-30 | $7700.00 | Window Closed / Lapsed |