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US4474019A Expired / Lapsed US ⏱️ 0.0 years remaining

Method of recirculating oil in refrigerating systems

Assignee: Stal Refrigeration AB
•
Filing: 1982-12-14
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Granted: 1984-10-02
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Expires: 2002-12-14
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Abstract

Abstract In the operation of a refrigeration system comprising a compressor, a condensor, an expansion valve and an evaporator which form a circulation circuit containing NH 3 refrigerant as a first medium, the compressor being lubricated by a second medium, oil, part of the oil quantity being continuously discharged from the compressor together with compressed NH 3 -gas into the circulation circuit for recirculation of oil to the compressor, continuously or batchwise, from the low pressure region of the circulation circuit, that is, the region located between the expansion valve and the compressor, the part of the oil transferred to the low pressure region (5, 6, 8, 9, 10, 11) of the circulation circuit is contacted with a third medium, added to the circulation circuit and which is substantially insoluble in liquid NH 3 , to form a liquid phase which is relatively free-flowing at the temperature prevailing in the low pressure region of the circulation circuit, whereupon said liquid phase, possibly after separation from any excess third medium, is fed to the compressor (1).

Inventors

  • 👤 Ludwig Albert

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-10-29 19:50
CPC Classifications
F; F25; F25B; F25B31/00; F25B31/002; F25B31/004

Claims Analysis

Total Claims: 6
Claim 1
Independent Claim 131 words
In the operation of a refrigerating system comprising a compressor, a condenser, an expansion valve and an evaporator connected in a circuit for circulation of an NH 3 refrigerant medium, the circuit having a low pressure region located between the expansion valve and the compressor, the compressor being lubricated by oil which is continuously discharged from the compressor together with compressed refrigerant gas, the method which comprises including in said circuit a further medium which is substantially insoluble in liquid NH 3 , combining said further medium with oil transferred to said low pressure region and thereby forming in said region a liquid phase which is free flowing at the operating temperature in said region, and feeding said liquid phase and N 3 from said low pressure region to the compressor.
Claim 2
Dependent Claim 131 words
In the operation of a refrigerating system comprising a compressor, a condenser, an expansion valve and an evaporator connected in a circuit for circulation of an NH 3 refrigerant medium, the circuit having a low pressure region located between the expansion valve and the compressor, the compressor being lubricated by oil which is continuously discharged from the compressor together with compressed refrigerant gas, the method which comprises including in said circuit a further medium which is substantially insoluble in liquid NH 3 , combining said further medium with oil transferred to said low pressure region and thereby forming in said region a liquid phase which is free flowing at the operating temperature in said region, and feeding said liquid phase and N 3 from said low pressure region to the compressor.
Claim 3
Dependent Claim 27 words
The method of claim 1, which comprises also separating said liquid phase from an excess of said further medium before feeding the liquid phase to the compressor.
Claim 4
Dependent Claim 14 words
The method of claim 1, in which said third medium is a low-boiling hydrocarbon.
Claim 5
Dependent Claim 16 words
The method of claim 1, in which said third medium is a mixture of low-boiling hydrocarbons.
Claim 6
Dependent Claim 24 words
The method of claim 1, in which said third medium is selected from the group consisting of propane, n-butane, isobutane and a mixture thereof.

References Cited (Backward Citations)

US2709340A Cited
US3021689A Cited
US3543880A Cited
US4275570A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1987-10-02 1988-04-02 1988-10-02 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1991-10-02 1992-04-02 1992-10-02 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1995-10-02 1996-04-02 1996-10-02 $7700.00 Window Closed / Lapsed

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