US4966493A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Process and apparatus for cleaning contaminated soil
Assignee: Linde GmbH
•
Filing: 1989-10-04
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Granted: 1990-10-30
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Expires: 2009-10-04
Abstract
Abstract A process and apparatus are provided for cleaning contaminated earth. The contaminated soil is first frozen using freezer boxes which are placed on the surface of the ground to be frozen. A refrigerant, preferably liquid nitrogen, is then introduced into the box until the soil is frozen to a desired depth and temperature. The frozen soil containing pollutants is then removed and placed in sealed containers for optional further treatment.
Inventors
- 👤 Dieter Rebhan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 03:41
CPC Classifications
E; E02; E02D; E02D19/00; E02D19/06; E02D19/12; E02D19/14; B; B09; B09C; B09C1/00; E02D3/00; E02D3/11; E02D3/115
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
100 words
A process for cleaning earth contaminated with toxic pollutants which may be in buried containers, the process comprising placing at least one freezer box on the surface only of the contaminated earth to be cleaned so as to avoid disturbing and/or releasing any buried pollutants into the surrounding earth or groundwater, introducing a cold refrigerant into the freezer box until the earth below the freezer box is frozen to a desired depth, and removing at least a portion of the frozen contaminated earth, and avoiding disturbing unfrozen contaminated earth which could release toxic pollutants into surrounding soil and the atmosphere.
Claim 2
Dependent Claim
100 words
A process for cleaning earth contaminated with toxic pollutants which may be in buried containers, the process comprising placing at least one freezer box on the surface only of the contaminated earth to be cleaned so as to avoid disturbing and/or releasing any buried pollutants into the surrounding earth or groundwater, introducing a cold refrigerant into the freezer box until the earth below the freezer box is frozen to a desired depth, and removing at least a portion of the frozen contaminated earth, and avoiding disturbing unfrozen contaminated earth which could release toxic pollutants into surrounding soil and the atmosphere.
Claim 3
Dependent Claim
28 words
The process of claim 1, wherein the cold refrigerant is liquid nitrogen refrigerant which is introduced into at least one freezer box, and gaseous nitrogen is discharged therefrom.
Claim 4
Dependent Claim
31 words
The process of claim 2, wherein the rate of introduction of the liquid nitrogen into the freezer box is adjusted as a function of the temperature of the gaseous nitrogen withdrawn.
Claim 5
Dependent Claim
38 words
The process of claim 1, further comprising placing a plurality of freezer boxes, optionally of various sizes, next to one another on the earth to be cleaned so that the contaminated earth is substantially covered with freezer boxes.
Claim 6
Dependent Claim
47 words
The process of claim 1, further comprising placing freezer boxes against exposed earthen sidewalls resulting from the removal of contaminated earth, and introducing cold refrigerant into the freezer boxes to freeze the earthen sidewalls, thereby to prevent the release of pollutants into the atmosphere and surrounding soil.
Claim 7
Dependent Claim
32 words
The process of claim 1, wherein the freezer box is maintained in contact with the surface of the earth until the earth is frozen up to a depth of about 3 m.
Claim 8
Dependent Claim
18 words
The process of claim 1, wherein a hoist is used to place the freezer box on the earth.
Claim 9
Dependent Claim
65 words
The process of claim 1, wherein freezing and removal of contaminated earth is performed in a series of steps in which a first earthen area is frozen, the freezer box used to freeze the first earthen area is then moved to a second earthen area which is frozen while at least a portion of the frozen first earthen area is removed to a desired depth.
Claim 10
Dependent Claim
49 words
The process of claim 1, wherein in the removal of frozen earth, a lower frozen layer thereof having a thickness sufficient to provide a vapor barrier is left intact and undisturbed, thereby to avoid the escape of toxic and/or noxious vapors into the atmosphere during excavation of contaminated earth.
Claim 11
Dependent Claim
38 words
The process of claim 1, wherein after excavation of frozen earth, the resultant earthen sidewalls of the excavation are frozen, thereby to avoid the escape from the sidewalls of toxic and/or noxious vapors into the atmosphere during excavation.
References Cited (Backward Citations)
US620112A
Cited
US2621022A
Cited
US3183675A
Cited
US3220470A
Cited
US3726095A
Cited
US4525282A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-10-29 | 1994-04-30 | 1994-10-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-10-29 | 1998-04-30 | 1998-10-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-10-29 | 2002-04-30 | 2002-10-30 | $7700.00 | Window Closed / Lapsed |