US4402834A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method for dewatering sludge-type material
Assignee: Albert Klein KG
•
Filing: 1981-04-06
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Granted: 1983-09-06
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Expires: 2001-04-06
Abstract
Abstract A process of dewatering sludge in which raw sludge and a flocculating agent are first mixed by suitable means, then fed into a rotary filter drum or similar device to effect thickening of the sludge and partial dewatering thereof. The now thickened sludge is then conveyed through a filtering assembly in which the sludge is subjected to further dewatering forces, which could be vacuum, centrifugal, static pressure, or pressure while moving along the filter surfaces, thereby further dewatering the sludge. The filtrate discharged from the filter drum and the filtering assembly and also wash water used for cleaning the filter surfaces in the filter drum and the filtering assembly are at least partly returned to the filter drum to effect total flocculation and recapture of sludge particles contained in the filtrate and the wash waters. In the partial dewatering of sludge in the drum filter, the solids in the wash water used to wash the drum filter are recaptured within the sludge in the drum before the thickened sludge or filtrate is discharged.
Inventors
- 👤 Wendel Bastgen
- 👤 Helmut Schreiber
- 👤 Eugen Grumbel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 21:16
CPC Classifications
C; C02; C02F; C02F11/00; C02F11/12; C02F11/121; B; B01; B01D; B01D33/00; B01D33/04; B01D33/06; B01D33/11; B01D33/44; B01D33/48; B01D33/50; B01D33/58; B01D33/60; B01D33/62; B01D33/64; B01D33/642; B01D36/00; B01D36/02; B01D37/00; B01D37/03; B30; B30B; B30B9/00; B30B9/02; B30B9/24; C02F11/123; C02F11/126
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
321 words
A process for continuous dewatering of sludge-type material containing solid particles comprising the steps of: receiving, from an outside process stream, material to be dewatered; adding the material to be dewatered into a mixing means, adding flocculant into said mixing means, mixing the material to be dewatered with said flocculant in said mixing means; passing the thus flocculated material through a reactor-thickener means in which water is separated therefrom through a filter surface of the reactor-thickener means while dewatered flocculated material remains on said filter surface, collecting the water separated from the flocculated material in the reactor-thickener means, axially advancing said dewatered flocculated material along said filter surface to an outlet end of said reactor-thickener means for discharge thereat, the flocculated material being progressively dewatered as it travels axially along said filter surface towards said outlet end, subjecting the thus dewatered flocculated material received from said reactor-thickener means as a solids mass to the action of a filtering means to extract filtrate from the material thereby causing solids from the material to form a sludge cake; discharging the cake; washing the filtering means with wash water obtained from the water collected from the reactor-thickener means to wash solids inclusive of flocculated solids from the filtering means; said wash water now containing said solids; returning at least part of said wash water with the flocculated solids contained therein after passage through the filtering means to the material to be dewatered for passage through the reactor-thickener means with the flocculated material received from the mixing means; the wash water and said flocculated material in said reactor-thickener means undergoing reaction on said filter surface for causing free water to be separated from the solids in the flocculated material and causing solids in the wash water to be captured by reaction with the flocculated solids in the flocculated material; and discharging clean free water from the reactor-thickener means as a discharged product from the process.
Claim 2
Dependent Claim
321 words
A process for continuous dewatering of sludge-type material containing solid particles comprising the steps of: receiving, from an outside process stream, material to be dewatered; adding the material to be dewatered into a mixing means, adding flocculant into said mixing means, mixing the material to be dewatered with said flocculant in said mixing means; passing the thus flocculated material through a reactor-thickener means in which water is separated therefrom through a filter surface of the reactor-thickener means while dewatered flocculated material remains on said filter surface, collecting the water separated from the flocculated material in the reactor-thickener means, axially advancing said dewatered flocculated material along said filter surface to an outlet end of said reactor-thickener means for discharge thereat, the flocculated material being progressively dewatered as it travels axially along said filter surface towards said outlet end, subjecting the thus dewatered flocculated material received from said reactor-thickener means as a solids mass to the action of a filtering means to extract filtrate from the material thereby causing solids from the material to form a sludge cake; discharging the cake; washing the filtering means with wash water obtained from the water collected from the reactor-thickener means to wash solids inclusive of flocculated solids from the filtering means; said wash water now containing said solids; returning at least part of said wash water with the flocculated solids contained therein after passage through the filtering means to the material to be dewatered for passage through the reactor-thickener means with the flocculated material received from the mixing means; the wash water and said flocculated material in said reactor-thickener means undergoing reaction on said filter surface for causing free water to be separated from the solids in the flocculated material and causing solids in the wash water to be captured by reaction with the flocculated solids in the flocculated material; and discharging clean free water from the reactor-thickener means as a discharged product from the process.
Claim 3
Dependent Claim
107 words
The process as claimed in claim 1, wherein said filtrate from the filtering means contains residual flocculated solids, said process further comprising returning at least part of said filtrate with the residual flocculated solids to the reactor-thickener means for passage therethrough with the flocculated material received from the mixing means to cause the combined filtrate and said flocculated material in the reactor-thickener means to undergo reaction on said filter surface of the reactor-thickener means for causing clean water to be separated from the solids in the flocculated material and causing the solids in the filtrate to be recaptured by reaction with flocculated solids in the flocculated material.
Claim 4
Dependent Claim
19 words
The process as claimed in claim 1, wherein the returned filtrate is introduced into the reactor-thickener means axially thereof.
Claim 5
Dependent Claim
34 words
The process as claimed in claim 1, wherein the material to be dewatered is subjected to a separating pressure in the reactor-thickener means which is less than the separating pressure in the filtering means.
Claim 6
Dependent Claim
40 words
The process as claimed in claim 1, wherein the reactor-thickener means comprises a rotatable drum having a filter surface, the dewatered, flocculated material traveling within the interior of said drum as it advances to the outlet end of the drum.
Claim 7
Dependent Claim
97 words
The process as claimed in claim 1 further comprising cleaning the filter surface of the reactor-thickener means with a cleaning liquid which is passed from one side of the filter surface to the other, said cleaning liquid picking up solids comprising flocculated material from said filter surface; and combining said cleaning liquid after cleaning the filter surface of the reactor-thickener means with material coming into the reactor-thickener means for causing the solids in the cleaning liquid to react with the flocculated material on the filter surface thereby at least partly removing solid material from the cleaning liquid.
Claim 8
Dependent Claim
29 words
The process as claimed in claim 1, wherein said solids mass is advanced as a flat layer along a rectilinear path in the filtering means to form said cake.
Claim 9
Dependent Claim
39 words
The process as claimed in claim 1 comprising causing the flocculated sludge in the reactor-thickener means to pass over successive annular partition walls forming baffles which define successive chambers through which the flocculated sludge travels in the reactor-thickener means.
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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) | 1986-09-05 | 1987-03-07 | 1987-09-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-09-05 | 1991-03-07 | 1991-09-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-09-05 | 1995-03-07 | 1995-09-06 | $7700.00 | Window Closed / Lapsed |