Patent US4101400A successfully refreshed from Google Patents.
US4101400A
Expired / Lapsed
US
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Method for dewatering sludge
Assignee: Machinefabriek W Hubert and Co
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Filing: 1977-05-20
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Granted: 1978-07-18
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Expires: 1997-05-20
Abstract
Abstract Sludge is dewatered to a dry content of more than 25% by a combination of (a) pre-conditioning the sludge by flocculation with polymeric flocculants; (b) pre-dewatering the conditioned sludge to a certain solid content corresponding with shovel consistency; (c) thereafter dewatering the sludge further through electroendosmosis under pressure. This combination renders it possible to produce a product having a dry content of more than about 30% irrespective of the origin of the sludge.
Inventors
- 👤 Roelf Pepping
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 08:02
CPC Classifications
B; B01; B01D; B01D61/00; B01D61/42; B01D61/56; B01D33/00; B01D33/04; B01D33/042; B01D33/58; B01D33/62; B01D33/64; B01D33/642; B01D33/70; B01D33/74; B01D33/745; B01D33/747; B01D35/00; B01D35/06; B30; B30B; B30B9/00; B30B9/02; B30B9/24; C; C02; C02F; C02F11/00; C02F11/12; C02F11/121; C02F11/123; C02F11/15
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
157 words
In a method of dewatering sludge having a dry content of less than 30% comprising continuously passing the sludge, on an endless belt member permeable to liquid, between electro-endosmosis electrodes and applying an electrical direct current through the sludge between the electrodes in a direction transverse to the direction of movement of the sludge, the improvement comprising: preconditioning the sludge by flocculation with polymeric flocculants; while the sludge is on the endless belt member and before the sludge is passed between the electro-endosmosis electrodes, pre-dewatering the sludge to shovel consistency; and while the sludge is on the endless belt member, subjecting the sludge to mechanical pressure at least at locations during and after the passage of the sludge between the electro-endosmosis electrodes to a sufficient extent at each location to provide an amount of dewatering greater than the amount achieved when the dewatering is accomplished with pressure applied only during passage of the sludge between the electrodes.
Claim 2
Dependent Claim
157 words
In a method of dewatering sludge having a dry content of less than 30% comprising continuously passing the sludge, on an endless belt member permeable to liquid, between electro-endosmosis electrodes and applying an electrical direct current through the sludge between the electrodes in a direction transverse to the direction of movement of the sludge, the improvement comprising: preconditioning the sludge by flocculation with polymeric flocculants; while the sludge is on the endless belt member and before the sludge is passed between the electro-endosmosis electrodes, pre-dewatering the sludge to shovel consistency; and while the sludge is on the endless belt member, subjecting the sludge to mechanical pressure at least at locations during and after the passage of the sludge between the electro-endosmosis electrodes to a sufficient extent at each location to provide an amount of dewatering greater than the amount achieved when the dewatering is accomplished with pressure applied only during passage of the sludge between the electrodes.
Claim 3
Dependent Claim
34 words
A method in accordance with claim 1 wherein said step of subjecting the electrodes to mechanical pressure further includes the application of pressure at a location before passage of the sludge between the electrodes.
Claim 4
Dependent Claim
88 words
A method in accordance with claim 1, wherein the sludge is passed between a plurality of pairs of electro-endosmosis electrodes, electrical direct current being applied through the sludge between each of said pairs in a direction transverse to the direction of movement of the sludge, and wherein said pre-dewatering step is before the sludge is passed between the first pair of said electrodes, and said step of subjecting the sludge to mechanical pressure includes applying mechanical pressure, during and after passage between each of the pairs of electrodes.
Claim 5
Dependent Claim
38 words
A method in accordance with claim 3, wherein said step of subjecting the electrodes to mechanical pressure further includes the application of pressure at a location before passage of the sludge between the first pair of said electrodes.
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) | 1981-07-17 | 1982-01-16 | 1982-07-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1985-07-17 | 1986-01-16 | 1986-07-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1989-07-17 | 1990-01-16 | 1990-07-18 | $7700.00 | Window Closed / Lapsed |