US4614577A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Apparatus for urea analysis
Assignee: Siemens AG
•
Filing: 1984-12-27
•
Granted: 1986-09-30
•
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 13:20
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.
References Cited (Backward Citations)
US3707455A
Cited
US3776819A
Cited
US3770607A
Cited
US3998717A
Cited
US4224125A
Cited
US4240889A
Cited
US4169779A
Cited
US4388166A
Cited
US4479865A
Cited
US4377446A
Cited
US4476005A
Cited
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 |