US4469176A
Expired / Lapsed
US
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Landfill gas recovery system and method with pressure symmetry
Assignee: Getty Synthetic Fuels Inc
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Filing: 1983-06-08
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Granted: 1984-09-04
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Expires: 2003-06-08
Abstract
Abstract In a landfill gas recovery system, the breakthrough danger is minimized, and the system efficiency is improved, by providing pressure-equalizing low-impedance gas paths such as aggregate-filled symmetry trenches positioned within the landfill and surrounding, at least partially, the primary collection zone. The symmetry trenches may be connected to the system's low-pressure source to serve as secondary collectors. A sensing trench positioned within the landfill along the periphery of the collector's zone of influence can be used to monitor the collector pressure and to automatically maintain it at a safe level. The sensing trench can also serve as a secondary equalizing path in heterogeneous landfills. Hot spots may advantageously be tapped by auxiliary collectors whose pressure level bears a predetermined proportional relationship to the primary collector pressure.
Inventors
- 👤 Stanley W. Zison
- 👤 Alex Roqueta
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 07:33
CPC Classifications
B; B09; B09B; B09B1/00; B09B1/006; E; E21; E21B; E21B43/00; E21B43/02; E21B43/04; E21B43/30; E21B43/305; Y; Y02; Y02C; Y02C20/00; Y02C20/20
Claims Analysis
Total Claims: 40
Claim 1
Independent Claim
92 words
A method of reducing air intrusion during the recovery of landfill gas from a landfill, comprising the steps of: (a) providing a gas collection zone in said landfill in proximity to its surface; (b) maintaining said collection zone at a pressure lower than the pressure of said gas in said landfill; and (c) positioning an elongated low-impedance gas path in said landfill in proximity to its surface and to said gas collection zone, said path extending in a generally non-radial direction with respect to said gas collection zone and being spaced therefrom.
Claim 2
Independent Claim
92 words
A method of reducing air intrusion during the recovery of landfill gas from a landfill, comprising the steps of: (a) providing a gas collection zone in said landfill in proximity to its surface; (b) maintaining said collection zone at a pressure lower than the pressure of said gas in said landfill; and (c) positioning an elongated low-impedance gas path in said landfill in proximity to its surface and to said gas collection zone, said path extending in a generally non-radial direction with respect to said gas collection zone and being spaced therefrom.
Claim 3
Dependent Claim
35 words
The method of claim 1, in which said lower pressure creates a zone of influence extending radially outwardly from said collection zone, and in which said gas path is located within said zone of influence.
Claim 4
Dependent Claim
14 words
The method of claim 1, in which said gas path surrounds said collection zone.
Claim 5
Dependent Claim
25 words
The method of claim 1, in which said gas path is in the nature of a generally horizontal trench below the surface of said landfill.
Claim 6
Dependent Claim
16 words
The method of claim 1, in which said gas path serves as a secondary collection zone.
Claim 7
Dependent Claim
71 words
A landfill gas recovery system, comprising: (a) gas collection means disposed in said landfill in proximity to its surface; (b) means for maintaining said collection means at a pressure lower than the pressure of said gas in said landfill; and (c) elongated low-impedance gas path means disposed in said landfill in proximity to, and generally parallel to, its surface at a location spaced from said collection means but in proximity thereto.
Claim 8
Dependent Claim
71 words
A landfill gas recovery system, comprising: (a) gas collection means disposed in said landfill in proximity to its surface; (b) means for maintaining said collection means at a pressure lower than the pressure of said gas in said landfill; and (c) elongated low-impedance gas path means disposed in said landfill in proximity to, and generally parallel to, its surface at a location spaced from said collection means but in proximity thereto.
Claim 9
Dependent Claim
19 words
The system of claim 6, in which the pressure in said collection means is maintained substantially lower than ambient.
Claim 10
Dependent Claim
36 words
The system of claim 7, further comprising pressure-varying means arranged to vary the pressure in said collection means in accordance with the difference in the ambient pressure and the pressure at a location within the landfill.
Claim 11
Dependent Claim
22 words
The system of claim 6, further comprising gas barrier means disposed in said landfill between said collection means and the landfill surface.
Claim 12
Dependent Claim
12 words
The system of claim 9, in which said trench contains coarse aggregate.
Claim 13
Dependent Claim
31 words
The system of claim 10, in which said collection means have a zone of influence extending radially outwardly therefrom, and said gas path means are positioned within said zone of influence.
Claim 14
Dependent Claim
31 words
The system of claim 6, in which said gas path means are in the form of a trench positioned in the active portion of said landfill immediately below its cover portion.
Claim 15
Dependent Claim
18 words
The system of claim 12, in which said gas path means include symmetry well means extending downwardly therefrom.
Claim 16
Dependent Claim
19 words
The system of claim 6, in which said gas path means surround said collection means in spaced relation thereto.
Claim 17
Dependent Claim
19 words
The system of claim 14, in which said gas path means extend generally transversely to said radially outward direction.
Claim 18
Dependent Claim
28 words
The system of claim 15, further comprising means for maintaining the pressure in said gas path means in a selectable proportion to the pressure in said collection means.
Claim 19
Dependent Claim
21 words
The system of claim 15, in which said gas path means is arranged to serve as a secondary gas collection means.
Claim 20
Dependent Claim
26 words
The system of claim 17, further comprising means for adjusting the pressure in said collection means in response to the pressure sensed by said sensing means.
Claim 21
Dependent Claim
31 words
The system of claim 6, in which said collection means have a zone of influence extending radially outwardly therefrom, and said gas path means are positioned within said zone of influence.
Claim 22
Dependent Claim
27 words
The system or claim 6, further including means for maintaining said gas path means at a pressure lower than the pressure of said gas in said landfill.
Claim 23
Dependent Claim
26 words
The system of claim 6, further comprising pressure sensing means disposed in said landfill outwardly of said gas path means with respect to said collection means.
Claim 24
Dependent Claim
35 words
The system of claim 21, in which said sensing means include sensing trench means disposed in said landfill, said sensing trench means constituting a second low-impedance gas path and being connected to a pressure sensor.
Claim 25
Dependent Claim
24 words
The system of claim 22, in which said sensing trench means at least partially surround said collection means and said first-named gas path means.
Claim 26
Dependent Claim
16 words
The system of claim 6, in which said collection means includes at least one shallow bore.
Claim 27
Dependent Claim
20 words
The system of claim 24, in which said collection means include a plurality of wells with overlapping zones of influence.
Claim 28
Dependent Claim
19 words
The system of claim 25, in which said gas path means surround said plurality of wells as a group.
Claim 29
Dependent Claim
68 words
A landfill gas recovery system, comprising: ( a) gas collection means positioned in said landfill in proximity to the surface thereof; (b) means for maintaining said gas collection means at a pressure lower than the pressure of said gas in said landfill; and (c) equalizing means for at least partially equalizing the gas pressure at a plurality of points in different directions radially outwardly of said collection means.
Claim 30
Dependent Claim
68 words
A landfill gas recovery system, comprising: ( a) gas collection means positioned in said landfill in proximity to the surface thereof; (b) means for maintaining said gas collection means at a pressure lower than the pressure of said gas in said landfill; and (c) equalizing means for at least partially equalizing the gas pressure at a plurality of points in different directions radially outwardly of said collection means.
Claim 31
Dependent Claim
24 words
The system of claim 27, in which said points are generally equidistant from said collection means to provide a generally uniform zone of influence.
Claim 32
Independent Claim
73 words
A method of recovering landfill gas from a landfill, comprising the steps of: (a) providing a gas collection zone in said landfill in proximity to its surface; (b) maintaining said collection zone at a pressure lower than the pressure of said gas in said landfill; and (c) at least partially equalizing the pressure of said gas in said landfill in at least a plurality of locations radially outward of said gas collection zone.
Claim 33
Independent Claim
73 words
A method of recovering landfill gas from a landfill, comprising the steps of: (a) providing a gas collection zone in said landfill in proximity to its surface; (b) maintaining said collection zone at a pressure lower than the pressure of said gas in said landfill; and (c) at least partially equalizing the pressure of said gas in said landfill in at least a plurality of locations radially outward of said gas collection zone.
Claim 34
Dependent Claim
20 words
The method of claim 29, in which said locations are positioned within the zone of influence of said collection zone.
Claim 35
Dependent Claim
23 words
The method of claim 29, further comprising the step of sensing the gas pressure in said landfill radially outwardly of said equalized locations.
Claim 36
Dependent Claim
23 words
The method of claim 31, further comprising the step of adjusting the pressure in said collection zone in accordance with said sensed pressure.
Claim 37
Dependent Claim
27 words
The method of claim 31, further comprising the step of adjusting the pressure in said collection zone in accordance with both said sensed pressure and ambient pressure.
Claim 38
Dependent Claim
89 words
A landfill gas recovery system for landfills having hot spots, comprising: (a) a primary gas collection means disposed in said landfill in proximity to its surface; (b) means for maintaining said primary collection means at a pressure lower than the pressure of said gas in said landfill; (c) elongated low-impedance gas path means disposed in said landfill in proximity to, and generally parallel to, its surface at a location spaced from said collection means but in proximity thereto; and (d) auxiliary gas collection means positioned at said hot spots.
Claim 39
Dependent Claim
89 words
A landfill gas recovery system for landfills having hot spots, comprising: (a) a primary gas collection means disposed in said landfill in proximity to its surface; (b) means for maintaining said primary collection means at a pressure lower than the pressure of said gas in said landfill; (c) elongated low-impedance gas path means disposed in said landfill in proximity to, and generally parallel to, its surface at a location spaced from said collection means but in proximity thereto; and (d) auxiliary gas collection means positioned at said hot spots.
Claim 40
Dependent Claim
26 words
The system of claim 34, further including means for maintaining said auxiliary collection means at a pressure proportional to the pressure in said primary collection means.
References Cited (Backward Citations)
US2207334A
Cited
US2266000A
Cited
US3705851A
Cited
US4026355A
Cited
US4183408A
Cited
US4276778A
Cited
US4323367A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1987-09-04 | 1988-03-05 | 1988-09-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-09-04 | 1992-03-05 | 1992-09-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-09-04 | 1996-03-05 | 1996-09-04 | $7700.00 | Window Closed / Lapsed |