Patent US4913771A successfully refreshed from Google Patents.
US4913771A
Expired / Lapsed
US
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Method for dewatering sludge or slurry
Assignee: Individual
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Filing: 1988-11-25
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Granted: 1990-04-03
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Expires: 2008-11-25
Abstract
Abstract Sludge or slurry is dewatered by passing it on a screw conveyor through a sealed vessel at a vacuum more negative than -10 inches of Hg. As a result, moisture is removed from the sludge or slurry as water vapor. The vessel is sealed from air by the presence of the sludge or slurry at the inlet and outlet port extents of the vessel.
Inventors
- 👤 Glover C. McIntyre
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 22:47
CPC Classifications
C; C02; C02F; C02F11/00; C02F11/12; C02F11/121; C02F11/125; B; B01; B01D; B01D3/00; B01D3/10; Y; Y10; Y10S; Y10S159/00; Y10S159/16; Y10S159/42; Y10S203/00; Y10S203/16; Y10T; Y10T137/00; Y10T137/8593; Y10T137/87571; Y10T137/87587; Y10T137/87643
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
136 words
Method of removing moisture from sludge or slurry comprising: transporting said sludge or slurry through the lower portion of a sealed vessel on a screw conveyor, passing said sludge or slurry into and out of said vessel through respective inlet and outlet port extents exposing said sludge or slurry on said conveyor to the environment in said sealed vessel during said exposure creating a vacuum more negative than -10" Hg. in said environment, removing from said environment water vapor resulting from said moisture from said sludge or slurry transporting said sludge or slurry on said conveyor so as to effect substantial air sealing at said inlet and outlet port extents, wherein the sludge or slurry entering and leaving the inlet and outlet port extents, respectively, has a sufficiently solid constituency to effect such substantial air sealing.
Claim 2
Dependent Claim
136 words
Method of removing moisture from sludge or slurry comprising: transporting said sludge or slurry through the lower portion of a sealed vessel on a screw conveyor, passing said sludge or slurry into and out of said vessel through respective inlet and outlet port extents exposing said sludge or slurry on said conveyor to the environment in said sealed vessel during said exposure creating a vacuum more negative than -10" Hg. in said environment, removing from said environment water vapor resulting from said moisture from said sludge or slurry transporting said sludge or slurry on said conveyor so as to effect substantial air sealing at said inlet and outlet port extents, wherein the sludge or slurry entering and leaving the inlet and outlet port extents, respectively, has a sufficiently solid constituency to effect such substantial air sealing.
Claim 3
Dependent Claim
30 words
Method as claimed in claim 1 with the added step of providing controlled air ingress to said environment and controlling said air to maintain the desired level of said vacuum.
Claim 4
Dependent Claim
19 words
Method as claimed in claim 1 wherein said vacuum is controlled to create negative pressures of about -29" Hg.
Claim 5
Dependent Claim
19 words
Method as claimed in claim 2 wherein said vacuum is controlled to create negative pressures of about -29" Hg.
Claim 6
Dependent Claim
22 words
Method as claimed in claim 1 wherein a venturi is used to create said vacuum and also to remove said water vapor.
Claim 7
Dependent Claim
22 words
Method as claimed in claim 2 wherein a venturi is used to create said vacuum and also to remove said water vapor.
Claim 8
Dependent Claim
22 words
Method as claimed in claim 3 wherein a venturi is used to create said vacuum and also to remove said water vapor.
Claim 9
Dependent Claim
22 words
Method as claimed in claim 4 wherein a venturi is used to create said vacuum and also to remove said water vapor.
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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) | 1993-04-02 | 1993-10-02 | 1994-04-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-04-02 | 1997-10-02 | 1998-04-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-04-02 | 2001-10-02 | 2002-04-03 | $7700.00 | Window Closed / Lapsed |