US3923655A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Level detection system
Assignee: Vesmat Investments Inc
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Filing: 1974-12-09
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Granted: 1975-12-02
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Expires: 1994-12-09
Abstract
Abstract A method and apparatus are provided for determining the sludge level in a secondary sedimentation tank of a sewage treatment system. The temperature differential between the sludge layer and the supernatant is used to detect the sludge level. Responsive to a differential temperature indicating a predetermined level of sludge in the tank, some of the sludge is wasted.
Inventors
- 👤 Ross E Mckinney
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:00
CPC Classifications
C; C02; C02F; C02F3/00; C02F3/006; B; B01; B01D; B01D21/00; B01D21/30; B01D21/34
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
77 words
Method for detecting the level of sludge in a sedimentation zone of a sewage treatment process, which method comprises measuring (1) a first temperature within the sludge layer in the sedimentation zone, and (2) a second temperature within the supernatant liquid above such sludge layer at a point spaced from such first temperature, and comparing the two temperatures to determine a temperature differential therebetween indicative of the upper portion of the sludge level between the two points.
Claim 2
Dependent Claim
77 words
Method for detecting the level of sludge in a sedimentation zone of a sewage treatment process, which method comprises measuring (1) a first temperature within the sludge layer in the sedimentation zone, and (2) a second temperature within the supernatant liquid above such sludge layer at a point spaced from such first temperature, and comparing the two temperatures to determine a temperature differential therebetween indicative of the upper portion of the sludge level between the two points.
Claim 3
Dependent Claim
23 words
The method of claim 1 wherein sewage is continuously flowed through the sedimentation zone and sludge and supernatant liquid are continuously withdrawn therefrom.
Claim 4
Dependent Claim
17 words
The method of claim 1 including the step of wasting sludge responsive to the detected sludge level.
Claim 5
Independent Claim
102 words
A METHOD FOR DETECTING THE LEVEL OF ACTIVATED SLUDGE IN A SECONDARY SEDIMENTATION ZONE IN A SEWAGE TREATMENT PROCESS, WHICH METHOD COMPRISES MEASURING THE TEMPERATURE OF THE LOWER ACTIVATED SLUDGE LAYER IN SAID SLUDGE ZONE AND THE TEMPERATURE OF THE SUPERNATANT LIQUID ABOVE SUCH ACTIVATED SLUDGE LAYER, DETERMINING A SHARP INCREASE IN TEMPERATURE OF SAID ACTIVATED SLUDGE OVER THE TEMPERATURE OF SAID SUPERNATANT LIQUID, WHEREBY THE DEPTH OF THE ACTIVATED SLUGED LAYER IS ALSO DETERMINED AS A RESULT OF THE TEMPERATURE DEFFERENTIAL, AND WASTING ACTIVATED SLUDGE RESPONSIVE TO SAID DETERMINATION TO MAINTAINED A CONTROLLED LEVEL TO OF ACTIVATED SLUDGE IN SAID ZONE
Claim 6
Independent Claim
102 words
A METHOD FOR DETECTING THE LEVEL OF ACTIVATED SLUDGE IN A SECONDARY SEDIMENTATION ZONE IN A SEWAGE TREATMENT PROCESS, WHICH METHOD COMPRISES MEASURING THE TEMPERATURE OF THE LOWER ACTIVATED SLUDGE LAYER IN SAID SLUDGE ZONE AND THE TEMPERATURE OF THE SUPERNATANT LIQUID ABOVE SUCH ACTIVATED SLUDGE LAYER, DETERMINING A SHARP INCREASE IN TEMPERATURE OF SAID ACTIVATED SLUDGE OVER THE TEMPERATURE OF SAID SUPERNATANT LIQUID, WHEREBY THE DEPTH OF THE ACTIVATED SLUGED LAYER IS ALSO DETERMINED AS A RESULT OF THE TEMPERATURE DEFFERENTIAL, AND WASTING ACTIVATED SLUDGE RESPONSIVE TO SAID DETERMINATION TO MAINTAINED A CONTROLLED LEVEL TO OF ACTIVATED SLUDGE IN SAID ZONE
Claim 7
Dependent Claim
25 words
The method of claim 4 in which temperatures are taken in the supernatant liquid and activated sludge each in a plurality of vertically spaced positions.
Claim 8
Dependent Claim
32 words
The method of claim 4 in which the activated sludge is wasted from said zone responsive to an accumulation of the depth of at least 0.05% of the volume of said zone.
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) | 1978-12-01 | 1979-06-02 | 1979-12-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-12-01 | 1983-06-02 | 1983-12-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-12-01 | 1987-06-02 | 1987-12-02 | $7700.00 | Window Closed / Lapsed |