US4486239A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Vapor degreasing system
Assignee: California Institute of Technology
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Filing: 1983-04-22
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Granted: 1984-12-04
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Expires: 2003-04-22
Abstract
Abstract A vapor degreasing method and apparatus wherein a second cooling coil is used to prevent escape of solvent or solvent vapor from a degreaser. Gaseous refrigerant from the second coil can be released to the freeboard space above the solvent vapor zone to provide a barrier layer.
Inventors
- 👤 Eugene R. DU Fresne
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 22:29
CPC Classifications
C; C23; C23G; C23G5/00; C23G5/02; C23G5/04
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
209 words
A method of providing a barrier layer to prevent discharge of solvent vapors in a solvent vapor degreasing process or the like comprising: (a) maintaining a liquid solvent bath in a tank; (b) heating said liquid solvent bath to a temperature sufficient to provide a solvent vapor zone above the upper surface of said liquid solvent; (c) cooling a first zone in the tank above said upper surface of said liquid solvent bath to a temperature sufficient to condense said solvent and to define an upper limit to said solvent vapor zone; (d) cooling a second zone in the tank above said first zone to a temperature lower than the temperature of said first zone to provide a safety zone whereby any solvent vapor escaping from said solvent vapor zone will be condensed or maintained at a level defined by said second zone, said second zone being cooled by a cooling receptacle containing a refrigerant confined therein; and (e) subsequently releasing said refrigerant as a gas into the tank from said cooling receptacle to form a second vapor layer above said solvent vapor zone, said second vapor layer having a molecular weight lower than the molecular weight of said solvent vapor but higher than the molecular weight of air.
Claim 2
Independent Claim
209 words
A method of providing a barrier layer to prevent discharge of solvent vapors in a solvent vapor degreasing process or the like comprising: (a) maintaining a liquid solvent bath in a tank; (b) heating said liquid solvent bath to a temperature sufficient to provide a solvent vapor zone above the upper surface of said liquid solvent; (c) cooling a first zone in the tank above said upper surface of said liquid solvent bath to a temperature sufficient to condense said solvent and to define an upper limit to said solvent vapor zone; (d) cooling a second zone in the tank above said first zone to a temperature lower than the temperature of said first zone to provide a safety zone whereby any solvent vapor escaping from said solvent vapor zone will be condensed or maintained at a level defined by said second zone, said second zone being cooled by a cooling receptacle containing a refrigerant confined therein; and (e) subsequently releasing said refrigerant as a gas into the tank from said cooling receptacle to form a second vapor layer above said solvent vapor zone, said second vapor layer having a molecular weight lower than the molecular weight of said solvent vapor but higher than the molecular weight of air.
Claim 3
Dependent Claim
33 words
A method according to claim 1 wherein CO 2 is used as the refrigerant for said second zone and wherein said CO 2 is maintained in a liquid phase in said cooling receptacle.
Claim 4
Dependent Claim
55 words
A method according to claim 1 wherein said second vapor layer is released from said cooling receptacle at a temperature above the freezing point of said solvent but at a temperature where the weight per volume of said second vapor layer will be higher than that of the ambient air above said second vapor layer.
Claim 5
Dependent Claim
30 words
A method according to claim 1 wherein water is provided as a cooling medium for the first zone and CO 2 is provided as the refrigerant for the second zone.
Claim 6
Dependent Claim
42 words
A method according to claim 1 wherein the refrigerant for said second zone is selected from the group consisting of CO 2 , CClF 3 , CHF 3 , Argon, CF 4 , CCl 2 F 2 , CHClF 2 and Krypton.
Claim 7
Independent Claim
183 words
An apparatus for solvent vapor degreasing or the like comprising: (a) a tank adapted to contain a liquid solvent bath in the bottom thereof and having a solvent vapor zone above said liquid solvent bath; (b) a first cooling coil positioned in said tank for cooling and condensing said solvent vapors, to define an upper level of said solvent vapor zone; (c) a second cooling coil positioned in said tank and mounted above said first cooling coil, with means for maintaining said second cooling coil at a temperature lower than the temperature to which said first cooling coil is cooled; said second cooling coil being provided with means to release a refrigerant contained therein into the tank whereby said refrigerant vaporizes to become a second vapor layer; and, (d) a freeboard zone being provided in said tank above said second cooling coil, and the refrigerant having a molecular weight lower than the molecular weight of said solvent vapor, but higher than the molecular weight of ambient air, whereby said second vapor layer is maintained as a barrier layer above said solvent vapor zone.
Claim 8
Independent Claim
183 words
An apparatus for solvent vapor degreasing or the like comprising: (a) a tank adapted to contain a liquid solvent bath in the bottom thereof and having a solvent vapor zone above said liquid solvent bath; (b) a first cooling coil positioned in said tank for cooling and condensing said solvent vapors, to define an upper level of said solvent vapor zone; (c) a second cooling coil positioned in said tank and mounted above said first cooling coil, with means for maintaining said second cooling coil at a temperature lower than the temperature to which said first cooling coil is cooled; said second cooling coil being provided with means to release a refrigerant contained therein into the tank whereby said refrigerant vaporizes to become a second vapor layer; and, (d) a freeboard zone being provided in said tank above said second cooling coil, and the refrigerant having a molecular weight lower than the molecular weight of said solvent vapor, but higher than the molecular weight of ambient air, whereby said second vapor layer is maintained as a barrier layer above said solvent vapor zone.
Claim 9
Dependent Claim
14 words
An apparatus according to claim 6 wherein said release means comprise an expansion valve.
Claim 10
Dependent Claim
14 words
An apparatus according to claim 7 wherein said expansion valve is a needle valve.
Claim 11
Dependent Claim
14 words
An apparatus according to claim 7 wherein said expansion valve is a fixed orifice.
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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) | 1987-12-04 | 1988-06-04 | 1988-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-12-04 | 1992-06-04 | 1992-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-12-04 | 1996-06-04 | 1996-12-04 | $7700.00 | Window Closed / Lapsed |