US4025309A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Carbon nitrogen test system
Assignee: Hach Co
•
Filing: 1976-02-26
•
Granted: 1977-05-24
•
Expires: 1996-02-26
Abstract
Abstract An analytical method for determining the elemental carbon and nitrogen contents of a sample. The sample, as a liquid or in finely divided solid form is placed in an evacuable pressure vessel and is then oxidized with a cupric oxide oxidizing agent to convert carbon to CO 2 , nitrogen to N 2 , and hydrogen to water. After cooling to condense the water, the resulting pressure provides a measure of the total carbon plus nitrogen content of the original sample. An aliquot of the gas is then treated for CO 2 removal, and the resulting change in volume thereby provides a measure of the ratio of carbon to nitrogen in the original sample.
Inventors
- 👤 Clifford C. Hach
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 09:07
CPC Classifications
G; G01; G01N; G01N7/00; G01N7/14; G01N31/00; G01N31/005; Y; Y10; Y10T; Y10T436/00; Y10T436/17; Y10T436/176152; Y10T436/176921; Y10T436/23
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
137 words
An analytical method for determining the elemental carbon and nitrogen contents of a sample, which comprises: mixing a predetermined amount of said sample, in finely divided form, with an excess of a cupric oxide oxidizing agent, evacuating a pressure vessel containing said mixture, heating said mixture to a temperature sufficient to effect oxidation of said sample and thereby convert carbon to CO 2 , nitrogen to N 2 , and hydrogen to water, cooling said vessel to condense water, determining the resulting gas pressure as a measure of the total carbon plus nitrogen content of the original sample, withdrawing a predetermined volume of said gas, sorbing CO 2 from said predetermined volume of gas, and determining the change in volume of said gas as a measure of the ratio of carbon to nitrogen in the original sample.
Claim 2
Dependent Claim
137 words
An analytical method for determining the elemental carbon and nitrogen contents of a sample, which comprises: mixing a predetermined amount of said sample, in finely divided form, with an excess of a cupric oxide oxidizing agent, evacuating a pressure vessel containing said mixture, heating said mixture to a temperature sufficient to effect oxidation of said sample and thereby convert carbon to CO 2 , nitrogen to N 2 , and hydrogen to water, cooling said vessel to condense water, determining the resulting gas pressure as a measure of the total carbon plus nitrogen content of the original sample, withdrawing a predetermined volume of said gas, sorbing CO 2 from said predetermined volume of gas, and determining the change in volume of said gas as a measure of the ratio of carbon to nitrogen in the original sample.
Claim 3
Dependent Claim
15 words
The method of claim 1 wherein said predetermined volume is withdrawn by a hypodermic syringe.
Claim 4
Dependent Claim
32 words
The method of claim 1 wherein said sorbing of the CO 2 and said measuring the change in volume of said gas are effected by the nitrometer technique with an alkaline reagent.
Claim 5
Dependent Claim
21 words
The method of claim 1 wherein said predetermined volume is withdrawn by an evacuated CO 2 absorber and associated pressure gauge.
References Cited (Backward Citations)
US2991684A
Cited
US3062624A
Cited
US3226197A
Cited
US3652227A
Cited
US3647387A
Cited
US3838969A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1980-05-23 | 1980-11-22 | 1981-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-05-23 | 1984-11-22 | 1985-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-05-23 | 1988-11-22 | 1989-05-24 | $7700.00 | Window Closed / Lapsed |