US3796543A
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Automatic analysis for phosphorous content
Assignee: ADMINISTRATOR ENVIRONMENTAL PR
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Filing: 1972-02-07
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Granted: 1974-03-12
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Expires: 1992-02-07
Abstract
Abstract A continuous automatic analytical system for measuring the phosphate content in aqueous fluids. First the phosphate containing sample is acidified, then reacted in an acid medium with molybdate to form molybdiphosphoric acid. Thereafter the molybdenum in the heterpoly acid is selectively reduced by hydrazine to a blue heterpoly complex. The quantity of blue color is directly proportional to the ortho-phosphate concentration in the sampling and a colorimeter reading thereof a measure of the phosphate content in the sample.
Inventors
- 👤 L Kamphake
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 19:57
CPC Classifications
G; G01; G01N; G01N21/00; G01N21/75; G01N21/77; G01N21/78; G01N21/783; G01N31/00; G01N31/02; G01N31/22; Y; Y10; Y10T; Y10T436/00; Y10T436/16
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
43 words
The method of claim 1 wherein successive sample portions are spaced apart by flow of air introduced at pulsed intervals into the combined stream of acidified sample and molybdate, said hydrazine bEing introduced into the liquid pulses in timed pulses in synchronization therewith.
Claim 2
Dependent Claim
18 words
The method of claim 1 wherein the mineral acid is sulfuric acid, and the hydrazine is hydrazine sulfate.
Claim 3
Dependent Claim
19 words
The method of claim 1 wherein the sample fluid being tested comprises the effluent from a waste sewage plant.
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) | 1977-03-11 | 1977-09-10 | 1978-03-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-11 | 1981-09-10 | 1982-03-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-11 | 1985-09-10 | 1986-03-12 | $7700.00 | Window Closed / Lapsed |