Patent US3799844A successfully refreshed from Google Patents.
US3799844A
Expired / Lapsed
US
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Instrumental method for plating and counting aerobic bacteria
Assignee: United States Department of Health and Human Services
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Filing: 1971-06-02
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Granted: 1974-03-26
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Expires: 1991-06-02
Abstract
Abstract A MACHINE FOR DEPOSITING A VARYING AMOUNT OF BACTERIA SOLUTION ON THE SURFACE OF A SOLIDIFIED AGAR PLATE IN THE CONFIGURATION OF AN ARCHIMEDES SPIRAL. THE AMOUNT OF SOLUTION DEPOSITED ON THE AGAR IS CONTINUOUSLY DECREASED, RESULTING IN A HIGHER CONCENTRATION OF BACTERIA PER UNIT LENGTH AT THE CENTER OF THE SPIRAL AND A DECREASING CONCENTRATION PER UNIT LENGTH AT THE EDGE OF THE PLATE. AFTER AN INCUBATION PERIOD THE BACTERIA BECOMES VISIBLE, AND ARE COUNTED BY INTERRUPTING A LIGHT BEAM INCIDENT TO A PHOTODIODE. THE CONCENTRATION OF AN UNKNOWN SOLUTION MAY BE DETERMINED BY VISUALLY COUNTING THE NUMBER OF COLONIES ON A DISCRETE AREA OF THE PLATE.
Inventors
- 👤 J Campbell
- 👤 J Gilchrist
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 21:01
CPC Classifications
G; G06; G06M; G06M11/00; C; C12; C12M; C12M23/00; C12M23/02; C12M23/10; C12M23/50; C12M33/00; C12M33/04; C12M41/00; C12M41/30; C12M41/36; G01; G01N; G01N15/00; G01N15/10; G01N15/14; G01N15/1468
Claims Analysis
Total Claims: 0
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References Cited (Backward Citations)
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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) | 1977-03-25 | 1977-09-24 | 1978-03-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-25 | 1981-09-24 | 1982-03-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-25 | 1985-09-24 | 1986-03-26 | $7700.00 | Window Closed / Lapsed |