Patent US4168236A successfully refreshed from Google Patents.
US4168236A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Consecutive, independent dewatering apparatus for improved sludge treatment
Assignee: Individual
•
Filing: 1977-12-23
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Granted: 1979-09-18
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Expires: 1997-12-23
Abstract
Abstract Apparatus is provided for the continuous treatment of sludge, which is made possible through the advantageous combination of at least two independent dewatering steps at consecutively higher pressures and increased dwell time. In a preferred embodiment there is provided a three stage process where there is a first dewatering at the pressure provided by gravity action, the sludge being strained through continuous filter pockets; a second moderate pressure stage with a drum filter press; and a third higher pressure stage.
Inventors
- 👤 Albert Bahr
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 12:23
CPC Classifications
B; B30; B30B; B30B9/00; B30B9/02; B30B9/24; B30B9/243; B01; B01D; B01D33/00; B01D33/01; B01D33/03; B01D33/04; B01D33/042; B01D33/044; B01D33/048; B01D33/056; B01D33/44; B01D33/48; B01D33/50; B01D33/58; B01D33/62; B01D33/64; B01D33/642; B01D33/646; B01D36/00; B01D36/02; B01D37/00; B01D37/03; B30B9/246
Claims Analysis
Total Claims: 18
Claim 1
Independent Claim
248 words
An apparatus for the removal of water from sludge comprising means for supplying sludge to be dewatered, a first dewatering stage coupled to said means for supplying sludge and comprising a rotating filtering medium for receiving said sludge and straining out an appreciable quantity of water therefrom by gravity pressure, a second dewatering stage coupled to the output of said first dewatering stage and comprising a first pair of endless rotating filter belts receiving between them the sludge output of said first dewatering stage, a series of pressure rollers, and a rotary drum against which said first filter belts are pressed by said series of pressure rollers, the pressure applied to the sludge by said pressure rollers being greater than gravity pressure, and a third dewatering stage coupled to the output of said second dewatering stage and comprising a second pair of endless rotating filter belts and at least two rotating platen belts pressure biased towards one another and defining nips between them through which said second pair of filter belts pass, said second pair of filter belts receiving the output sludge from said second dewatering stage prior to their entry between said platen belts, said platen belts applying pressure to the sludge received from said second dewatering stage which is higher than the pressure applied to the sludge in the second dewatering stage by said pressure rollers, each of said first, second, and third dewatering stages retaining the sludge passing therethrough for successively longer periods of time.
Claim 2
Independent Claim
248 words
An apparatus for the removal of water from sludge comprising means for supplying sludge to be dewatered, a first dewatering stage coupled to said means for supplying sludge and comprising a rotating filtering medium for receiving said sludge and straining out an appreciable quantity of water therefrom by gravity pressure, a second dewatering stage coupled to the output of said first dewatering stage and comprising a first pair of endless rotating filter belts receiving between them the sludge output of said first dewatering stage, a series of pressure rollers, and a rotary drum against which said first filter belts are pressed by said series of pressure rollers, the pressure applied to the sludge by said pressure rollers being greater than gravity pressure, and a third dewatering stage coupled to the output of said second dewatering stage and comprising a second pair of endless rotating filter belts and at least two rotating platen belts pressure biased towards one another and defining nips between them through which said second pair of filter belts pass, said second pair of filter belts receiving the output sludge from said second dewatering stage prior to their entry between said platen belts, said platen belts applying pressure to the sludge received from said second dewatering stage which is higher than the pressure applied to the sludge in the second dewatering stage by said pressure rollers, each of said first, second, and third dewatering stages retaining the sludge passing therethrough for successively longer periods of time.
Claim 3
Dependent Claim
44 words
An apparatus of claim 1 wherein said first pair of endless rotating filter belts is independent of said second pair of endless rotating filter belts and both said first and second pairs of endless rotating filter belts are independent of said rotating filtering medium.
Claim 4
Dependent Claim
22 words
An apparatus for dewatering sludge as in claim 1 wherein said rotating filtering medium of said first stage comprises rotating filter pockets.
Claim 5
Dependent Claim
52 words
An apparatus of claim 3 wherein three platen belts are provided in said third dewatering stage defining two parallel nips and said second pair of endlessly rotating filter belts pass through said two parallel nips, and the two outer platen belts are pressurized towards engagement with the central and stationary platen belt.
Claim 6
Dependent Claim
20 words
An apparatus of claim 3 wherein the pressure biasing of the platen belts towards one another is provided by springs.
Claim 7
Dependent Claim
21 words
An apparatus of claim 3 wherein the pressure biasing of the platen belts towards one another is provided by hydraulic cylinders.
Claim 8
Dependent Claim
24 words
An apparatus of claim 3 wherein the pressure biasing of the platen belts towards one another is provided by pneumatic or hydraulic pressure cushions.
Claim 9
Dependent Claim
34 words
An apparatus of claim 3 wherein the platen belts are mounted on rollers having spindles and a pressure biasing means is provided acting on said spindles to bias said platen belts towards one another.
Claim 10
Dependent Claim
37 words
An apparatus of claim 3 wherein each platen belt runs over two reversing rollers and a continuous pressing plate or pressing support is positioned between the reversing rollers for each platen belt on the pressing side thereof.
Claim 11
Dependent Claim
28 words
An apparatus of claim 3 wherein the nips bounded by the platen belts and said second pair of filter belts passing through said nips are disposed substantially vertically.
Claim 12
Dependent Claim
22 words
An apparatus of claim 3 wherein said apparatus comprises cleaning means for said second pair of filter belts of the platen press.
Claim 13
Dependent Claim
36 words
An apparatus of claim 3 wherein the outlet of said first dewatering stage comprising said rotating filter pockets is disposed at a level above the level of a preliminary dewatering section of said second dewatering stage.
Claim 14
Dependent Claim
42 words
An apparatus of claim 3 wherein a chamber is provided upstream of said first dewatering stage, said chamber being equipped with a forcing means for mixing sludge with a floculant, the output of said chamber being coupled to said first dewatering stage.
Claim 15
Dependent Claim
19 words
An apparatus of claim 13 wherein said chamber is provided inside said rotary drum of said second dewatering stage.
Claim 16
Dependent Claim
16 words
An apparatus of claim 3 wherein said rotating filter pockets are disposed above a rotating drum.
Claim 17
Dependent Claim
16 words
An apparatus of claim 3 wherein said rotating filter pockets are a part of a belt.
Claim 18
Dependent Claim
32 words
An apparatus of claim 3 wherein one of said second pair of filter belts is disposed below the discharge point of said filter pockets to receive sludge strained by said filter pockets.
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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) | 1982-09-17 | 1983-03-19 | 1983-09-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-09-17 | 1987-03-19 | 1987-09-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-09-17 | 1991-03-19 | 1991-09-18 | $7700.00 | Window Closed / Lapsed |