US5337572A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryogenic refrigerator with single stage compressor
Assignee: Azenta Inc
•
Filing: 1993-05-04
•
Granted: 1994-08-16
•
Expires: 2013-05-04
Abstract
Abstract A closed cycle refrigerating system for cryogenic temperatures using a single stage compressor with a refrigerant comprising a gas mixture. The refrigerating system includes a heat exchanger having a throttling orifice which is arranged to provide refrigeration, and a single stage oil lubricated compressor for compressing the refrigerant. The compressor is typically of the rolling piston type. The refrigerant is a mixture of at least one cryogenic gas having a normal boiling point below 120 degrees K and at least two other gases having normal boiling point temperatures below 300 degrees different from each other and from said one gas. There is also included means for cooling the compressed refrigerant and for circulating the cooled refrigerant to the heat exchanger and its throttling orifice and then back to the compressor. The system does not require any cascaded heat exchangers or intermediate phase separators.
Inventors
- 👤 Ralph C. Longsworth
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 14:21
CPC Classifications
F; F25; F25B; F25B9/00; F25B9/02; F25B9/002; F25B9/006; F25B2400/00; F25B2400/12; F25B31/00; F25B31/002; F25B31/004
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
160 words
A closed cycle refrigerating system of the type having a heat exchanger with a throttling orifice for providing cooling temperatures below 150 degrees K and above 65 degrees K in a normal ambient environment comprising, a refrigerant comprising a mixture of at least one cryogenic gas having a normal boiling temperature below 130 degrees K and at least two other gases having normal boiling temperatures below 300 degrees K different from each other and from said one gas, a single stage oil-lubricated compressor operative in said normal ambient environment for compressing said refrigerant, said compressor having a volumetric efficiency of at least 50% when producing a pressure ratio of at least 5 to 1 in said refrigerant, means for separating oil from said compressed refrigerant and for delivering said separated oil back to said compressor, and means for cooling said compressed refrigerant and for circulating said cooled refrigerant through said heat exchanger and throttling orifice and back to said compressor.
Claim 2
Dependent Claim
160 words
A closed cycle refrigerating system of the type having a heat exchanger with a throttling orifice for providing cooling temperatures below 150 degrees K and above 65 degrees K in a normal ambient environment comprising, a refrigerant comprising a mixture of at least one cryogenic gas having a normal boiling temperature below 130 degrees K and at least two other gases having normal boiling temperatures below 300 degrees K different from each other and from said one gas, a single stage oil-lubricated compressor operative in said normal ambient environment for compressing said refrigerant, said compressor having a volumetric efficiency of at least 50% when producing a pressure ratio of at least 5 to 1 in said refrigerant, means for separating oil from said compressed refrigerant and for delivering said separated oil back to said compressor, and means for cooling said compressed refrigerant and for circulating said cooled refrigerant through said heat exchanger and throttling orifice and back to said compressor.
Claim 3
Dependent Claim
15 words
The refrigerating system of claim 1 wherein said oil-lubricated compressor comprises a rolling piston compressor.
Claim 4
Dependent Claim
33 words
The refrigerating system of claim 1 wherein said one gas comprises 20% to 45% Nitrogen, and at least two of said other gases are selected from Methane, Ethane, Ethylene, Propane, Isopentane and Isobutane.
Claim 5
Dependent Claim
40 words
The refrigerating system of claim 2 wherein said gas having a boiling point below 130 degrees K comprises Nitrogen, Argon and/or Methane individually or in some combination, and said other gases are selected from Ethane, Ethylene, Propane, Isopentane and Isobutane.
Claim 6
Dependent Claim
32 words
The refrigerating system of claim 4 wherein said Nitrogen or Argon or Methane are included in said mixture in an amount 20% to 45% individually or 20% to 60% in any combination.
Claim 7
Dependent Claim
14 words
The refrigerating system of claim 2 wherein said heat exchanger is a Joule-Thomson cryostat.
Claim 8
Dependent Claim
33 words
The refrigerating system of claim 2 wherein said rolling piston compressor produces pressures in said refrigerant in the range of 0.05 to 0.5 MPa low pressure and 1.5 to 3.0 MPa high pressure.
Claim 9
Dependent Claim
33 words
The refrigerating system of claim 7 wherein said gas mixture comprises 0.36 Nitrogen, 0.2 Methane, 0.12 Ethylene, 0.2 Propane, and 0.12 Isobutane within a variation of the percentages of plus or minus 30%.
Claim 10
Dependent Claim
34 words
The refrigerating system of claim 8 wherein said rolling piston compressor produces in the refrigerant a low pressure in the neighborhood of 0.35 MPa and a high pressure in the neighborhood of 2.45 MPa.
Claim 11
Dependent Claim
32 words
The refrigerating system of claim 2 wherein said heat exchanger having a throttling orifice comprises a Joule-Thomson cryostat, and all of the compressed and cooled refrigerant is passed through said throttling orifice.
Claim 12
Dependent Claim
68 words
The refrigerating system of claim 7 wherein said one gas in said gas mixture comprises Nitrogen and at least two other gases in said mixture are selected from Methane, Ethane, Ethylene, Propane, and Isobutane, and the pressure ratio produced by said rolling piston compressor is in the range of 6-7 to 1, thereby to provide refrigerating temperatures in the range of 90 degrees K to 125 degrees K.
Claim 13
Dependent Claim
25 words
The refrigerating system of claim 7 wherein said rolling piston compressor has a volumetric efficiency above 70% at a pressure ratio of 4 to 1.
Claim 14
Dependent Claim
31 words
The refrigerating system of claim 2, wherein said gas mixture comprises 0.35 Methane, 0.25 Ethane, 0.25 Propane and 0.15 Isobutane within a variation of the percentages of plus or minus 30%.
Claim 15
Dependent Claim
37 words
The refrigerating system of claim 1 wherein said single stage compressor produces a pressure ratio in said refrigerant in the range of 5-18 to 1 and has a volumetric efficiency in the range of 50% to 75%.
Claim 16
Dependent Claim
82 words
The refrigerating system of claim 14 wherein said at least one gas having a boiling temperature below 130 degrees K is selected from Nitrogen, Argon and Methane; said at least two other gases having a boiling temperature below 300 degrees K are selected from Nitrogen, Argon, Methane, Ethane, Ethylene, Propane, Isopentane and Isobutane; said cooling means comprises an aftercooler; and said oil separating means is connected to separate oil from said compressed refrigerant before said compressed refrigerant is cooled by said aftercooler.
Claim 17
Dependent Claim
80 words
The refrigerating system of claim 14 wherein said at least one gas having a boiling temperature below 130 degrees K is selected from Nitrogen, Argon and Methane; said at least two other gases having a boiling temperature below 300 degrees K are selected from Nitrogen, Argon, Methane, Ethane, Ethylene, and Propane; said cooling means comprises an aftercooler; and said oil separating means is connected to separate oil from said compressed refrigerant after said compressed refrigerant is cooled by said aftercooler.
References Cited (Backward Citations)
US3204422A
Cited
US3413819A
Cited
GB1336892A
Cited
US3698202A
Cited
US3768273A
Cited
SU627154A1
Cited
SU918298A1
Cited
SU1054400A1
Cited
SU1089099A1
Cited
US4718251A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1997-08-15 | 1998-02-14 | 1998-08-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 2001-08-15 | 2002-02-14 | 2002-08-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2005-08-15 | 2006-02-14 | 2006-08-16 | $7700.00 | Window Closed / Lapsed |