(12) United States Patent
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`Thomas et al.
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`(10) Patent No.:
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`(45) Date of Patent:
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`US 6,516,837 B2
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`Feb. 11,2003
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`US006516837B2
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`GB
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`JP
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`JP
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`JP
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`JP
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`WO
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`WO
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`(57)
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`2/1996
`2291884 A
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`1/1992
`18491-1992
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`3/1993
`59388-1993
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`5/1993
`125374-1993
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`8/1994
`220430-1994
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`77364-1995
`3/1995
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`173462-1995
`7/1995
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`41448-1996
`2/1996
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`85798-1996
`4/1996
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`157847-1996
`6/1996
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`311471-1996
`11/1996
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`2/1997
`40981-1997
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`5/1997
`118879-1997
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`208940-1997
`8/1997
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`306289-1998
`11/1998
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`44938-2000
`2/2000
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`94/12544
`5/1995
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`95/01717
`2/1996
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`95/01737
`2/1996
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`W0 96 07721
`3/1996
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`5/1997
`96/02574
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`6/1998
`97/03286
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`W0 99 36485
`7/1999
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`OTHER PUBLICATIONS
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`J. Reyes—Gavilan, G. Flak, T. Tricak, C. Barbour, “Enhanced
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`Naphthenic Refrigeration Oils for Household Refrigerator
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`Systems”, ASHRAE Transactions: Research, pp. 95-106
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`(No Date).
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`S. Sundaresan, M. Pate, T. Doerr, D. Ray, “AComparison of
`the Effects of Poe and Mineral Oil Lubricants on the
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`In—Tube Evaporation of R—22, R—407C and R—410A”,
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`pp.187—192 (No Date).
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`S. Sundaresen, J. Judge, W.Chu, R.R. Rademacher, “A
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`Comparison of Oil Return Characteristics of R—22/Mineral
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`Oil and its HFC Alternatives (R—407C andR—410A) with
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`Mineral Oil and POE in a Residential Heat Pump”, pp.
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`297-302 (No Date).
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`* cited by examiner
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`Primary Examiner—Steven 0. Douglas
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`(74) Attorney, Agent, or Firm—Colleen D. Szuch
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`ABSTRACT
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`Provided are methods of introducing environmentally desir-
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`able refrigerants into refrigeration systems. The present
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`methods involve recharging a refrigerant system that con-
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`tains a chlorine-containing refrigerant and a lubricant com-
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`prising the steps of (a) removing the chlorine-containing
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`refrigerant from the refrigeration system While retaining a
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`substantial portion of the lubricant in said system; and (b)
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`introducing to said system a composition comprising:
`a
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`refrigerant; (ii) a surfactant; and (iii) a solubilizing agent.
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`17 Claims, No Drawings
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`.......... .. C09K/5/04
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`.......... .. C09K/5/04
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`C09K/5/04
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`.......... .. C09K/5/04
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`C09K/5/04
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`.......... .. C09K/5/04
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`(75)
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`(54) METHOD OF INTRODUCING
`REFRIGERANTS INTO REFRIGERATION
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`SYSTEMS
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`Inventors: Raymond Hilton Percival Thomas,
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`Niagara County, NY (US); Roy Phillip
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`Robinson, Erie County, NY (US);
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`Rajiv Ratna Singh, Erie County, NY
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`(US); David Paul Wilson, Erie County,
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`NY (US)
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`(73) Assignee: Honeywell International Inc.,
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`Morristown, NJ (US)
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`Subject to any disclaimer, the term of this
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`patent is extended or adjusted under 35
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`U.S.C. 154(b) by 0 days.
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`( * ) Notice:
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`(22)
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`(65)
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`(60)
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`(21) Appl. No.: 09/943,063
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`Filed:
`Aug. 30, 2001
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`Prior Publication Data
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`US 2002/0046568 A1 Apr. 25, 2002
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`Related U.S. Application Data
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`Provisional application No. 60/235,746, filed on Sep. 27,
`2000.
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`(51)
`Int. Cl.7 ................................................ .. B65B 1/04
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`(52) U.S. Cl.
`........................... .. 141/67; 141/82; 141/98;
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`141/65; 252/68
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`(58) Field of Search ............................ .. 141/65, 67, 98,
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`141/82; 252/67, 68, 69
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`(56)
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`DE
`EP
`EP
`EP
`EP
`EP
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`References Cited
`U.S. PATENT DOCUMENTS
`
`
`
`10/1992 Thomas et al.
`5,154,846 A
`
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`
`
`............. .. 252/68
`10/1993 Thomas et al.
`5,254,280 A
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`
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`
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`5,370,812 A * 12/1994 Brown ...................... .. 252/68
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`5,372,737 A
`12/1994 Spauschus .
`252/68
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`. . . .. 252/68
`5,520,833 A
`5/1996 Kaneko . . . . .
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`
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`5,750,046 A *
`5/1998 Wheeler .................... .. 252/68
`
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`
`
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`5,792,383 A
`8/1998 Reyes-Gavilan et al.
`252/68
`
`
`
`
`
`252/68
`5,866,030 A
`2/1999 Reyes-Gavilan et al.
`5,954,995 A
`9/1999 Goble ....................... .. 252/67
`
`
`
`
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`6,074,563 A
`6/2000 Kaneko ..................... .. 252/68
`
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`
`
`FOREIGN PATENT DOCUMENTS
`
`
`
`4226431 A1
`8/1992
`.......... .. C09K/5/04
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`
`
`
`0693546 A1
`...... .. C10M/171/00
`1/1996
`
`
`
`
`0 784 090 A
`7/1997
`
`
`
`
`0659862 B1
`.......... .. C09K/5/04
`6/1998
`
`
`
`
`0 908 509 A
`4/1999
`
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`0699742 B1
`...... .. C10M/171/00
`5/1999
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`Page 1 of 5
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`Arkema Exhibit 1018
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`Arkema Exhibit 1018
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`Page 1 of 5
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`

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`US 6,516,837 B2
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`2
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`efficient and more desirable method for introducing envi-
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`ronmentally desirable refrigerants into refrigeration sys-
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`tems. These and other objects are achieved by the present
`invention as described below.
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`DESCRIPTION OF THE INVENTION AND
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`PREFERRED EMBODIMENTS
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`The present invention is directed to methods of introduc-
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`ing environmentally desirable refrigerants into refrigeration
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`systems. The methods of the present invention overcome the
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`disadvantages of the prior art by facilitating the introduction
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`of environmentally desirable, non-chlorine-containing
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`refrigerant compositions into refrigeration systems without
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`the removal of hydrocarbon-based lubricant already present
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`in the system. Accordingly, non-chlorine-containing refrig-
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`erant compositions can be added to existing refrigeration
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`systems containing hydrocarbon-based oils, such as mineral
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`oils or alkyl benzenes, to form efficient and environmentally
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`desirable refrigerant/lubricant systems with greater ease and
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`less expense than traditional methods.
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`According to certain embodiments, the present methods
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`involve recharging a refrigerant system that contains a
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`chlorine-containing refrigerant and a lubricant comprising
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`the steps of (a) removing the chlorine-containing refrigerant
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`from the refrigeration system while retaining a substantial
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`portion of the lubricant in said system; and (b) introducing
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`to said system a composition comprising:
`a refrigerant;
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`(ii) a surfactant; and (iii) a solubilizing agent. As used
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`herein, the term “substantial portion” refers generally to a
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`quantity of lubricant which is at least about 50% (by weight)
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`of the quantity of lubricant contained in the refrigeration
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`system prior to removal of the chlorine-containing refriger-
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`ant. Preferably, the substantial portion of lubricant in the
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`system according to the present invention is a quantity of at
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`least about 60% of the lubricant contained originally in the
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`refrigeration system, and more preferably a quantity of at
`least about 70%.
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`According to certain alternative embodiments, the present
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`methods involve generally the steps of (a) providing a
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`refrigeration system comprising a chamber having therein a
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`hydrocarbon-based lubricant and substantially no chlorine-
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`containing refrigerant; and (b) introducing to said chamber
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`a composition comprising:
`a refrigerant; (ii) a surfactant;
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`and (iii) a solubilizing agent.
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`As used herein the term “refrigeration system” refers
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`generally to any system or apparatus, or any part or portion
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`of such a system or apparatus, which employs a refrigerant
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`to provide cooling. Such refrigeration systems include, for
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`example, air conditioners, electric refrigerators, chillers,
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`transport refrigeration systems, commercial refrigeration
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`systems and the like.
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`Those of skill in the art will recognize that the refrigera-
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`tion systems used in the methods of the present invention
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`generally comprise a chamber in which both a refrigerant
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`and lubricant are contained and through which the refriger-
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`ant and lubricant can be circulated. According to certain
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`embodiments of the present invention, the removal step (a)
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`comprises removing a chlorine-containing refrigerant from a
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`refrigeration system, especially from a chamber within the
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`system, while leaving a substantial amount of lubricant, and
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`preferably a hydrocarbon-based lubricant, in the system.
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`Any of a wide range of known methods can be used to
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`remove chlorine-containing refrigerants from a refrigeration
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`system while removing less than a major portion of the
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`lubricant contained in the system. According to preferred
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`embodiments, the lubricant is a hydrocarbon-based lubricant
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`10
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`15
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`25
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`60
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`65
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`1
`METHOD OF INTRODUCING
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`REFRIGERANTS INTO REFRIGERATION
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`SYSTEMS
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`CROSS-REFERENCE TO RELATED
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`APPLICATIONS
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`This application claims the benefit of U.S. Provisional
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`Application No. 60/235,746 filed Sep. 27, 2000.
`FIELD OF INVENTION
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`The present invention relates generally to methods of
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`introducing environmentally desirable refrigerants into
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`refrigeration systems. More specifically,
`this invention
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`relates to methods for removing chlorofiuorocarbons and
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`hydrochlorofiuorocarbons from refrigeration systems and
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`charging refrigeration systems with environmentally desir-
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`able refrigerant compositions.
`BACKGROUND
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`The use of chlorine-containing refrigerants, such as chlo-
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`rofiuorocarbons (“CFC’s”), hydrochlorofiuorcarbons
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`(‘‘HCFCs’’) and the like, as refrigerants in air conditioning
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`and refrigerating equipment has become disfavored due to
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`the ozone-depleting properties associated with such com-
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`pounds. As a result, it has become desirable to “retrofit”
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`chlorine-containing refrigeration systems by replacing
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`chlorine-containing refrigerants with non-chlorine-
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`containing refrigerant compounds which will not deplete the
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`ozone layer, such as hydrofluorocarbons (“HFC’s”).
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`Unfortunately, many non-chlorine-containing
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`refrigerants, including HFC’s, are relatively insoluble and/or
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`immiscible in the types of lubricants used traditionally with
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`CFC’s (“hydrocarbon-based lubricants”) including,
`for
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`example, mineral oils, alkylbenzenes or polyalphaolefins.
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`This is problematic because in order for a refrigerant/
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`lubricant system to work efficiently within a refrigeration or
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`air conditioning system, the refrigerant must be sufficiently
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`soluble in the lubricant over a wide range of operating
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`temperatures. Such solubility lowers the viscosity of the
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`lubricant and allows it to flow more easily throughout the
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`system. In the absence of such solubility, lubricants tend to
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`become lodged in the coils of the refrigeration system
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`evaporator, as well as other parts of the system, and thus
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`reduce the system efficiency.
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`To avoid such problems, traditional methods for retrofit-
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`ting refrigeration systems require the steps of: (a) removing
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`all chlorine-containing refrigerant and at least 95% of the
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`hydrocarbon-based lubricant from the system; followed by
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`(b) introducing to the system a new non-chlorine-containing
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`refrigerant composition and a replacement lubricant com-
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`patible therewith.
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`The present inventors have come to appreciate that such
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`traditional methods are disadvantageous for several reasons.
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`For example, one disadvantage is that removal of lubricants,
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`and particularly hydrocarbon-based lubricants which have
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`heretofore frequently been used, from a refrigeration system
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`via flushing or other methods tends to be time-consuming
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`and costly. Another disadvantage is that many replacement
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`lubricants, such as esters, are very sensitive to moisture and
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`must be handled with great care. Yet another disadvantage is
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`that replacement lubricants do not perform efficiently certain
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`functions, such as noise reduction, which are associated with
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`hydrocarbon-based lubricants.
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`Recognizing these and other drawbacks of the prior art,
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`the present inventors have perceived a need for a new,
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`Page 2 of 5
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`Page 2 of 5
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`3
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`and the removal step results in at least about 90%, and even
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`more preferably at least about 95 %, of said lubricant remain-
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`ing in the system. For example, because refrigerants are
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`quite volatile relative to traditional hydrocarbon-based lubri-
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`cants (the boiling point of refrigerants are generally under
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`10° C. whereas the boiling point of mineral oils are generally
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`over 200° C.), the removal step may readily be performed by
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`pumping chlorine-containing refrigerants in the gaseous
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`state out of a refrigeration system containing liquid state
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`lubricants. Such removal can be achieved in any of a number
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`of ways known in the art, including, the use of a refrigerant
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`recovery system, such as the recovery system manufactured
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`by Robinair of Ohio. Alternatively, a cooled, evacuated
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`refrigerant container can be attached to the low pressure side
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`of a refrigeration system such that the gaseous refrigerant is
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`drawn into the evacuated container and removed. Moreover,
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`a compressor may be attached to a refrigeration system to
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`pump the refrigerant from the system to an evacuated
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`container. In light of the above disclosure, those of ordinary
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`skill in the art will be readily able to remove chlorine-
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`containing lubricants from refrigeration systems and to
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`provide a refrigeration system comprising a chamber having
`
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`
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`therein a hydrocarbon-based lubricant and substantially no
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`chlorine-containing refrigerant according to the present
`invention.
`
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`The introduction step (b) of the present invention com-
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`prises introducing to a hydrocarbon-based lubricant a com-
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`position comprising:
`a refrigerant; (ii) a surfactant; and
`
`
`
`(iii) a solubilizing agent.
`
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`Any of a wide range of non-chlorine-containing refriger-
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`ants can be used in the present invention. Examples of
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`refrigerants suitable for use in the present invention include
`
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`
`
`HFC’s, such as 1,1,1,2-tetrafluoroethane (“R-134a ”), pen-
`
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`tafluoroethane (“R-125”) difluoromethane (“R-32”),
`iso-
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`mers of trifluoroethane (“R-143” and “R-143a”), isomers of
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`pentafluoropropane (for example, “R-245fa”, “B-245ea”,
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`“R-245ca” and “B-245eb”), and mixtures thereof, such as,
`
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`R-407A, R-407B, R-407C, R-410A, R-404A, R-507A,
`R-508A and R-508B.
`
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`The surfactant used in the present invention can be any
`
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`
`surfactant which, when added to a composition comprising
`
`
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`
`
`a hydrocarbon-based lubricant component and a non-
`
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`
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`chlorine-containing refrigerant component,
`increases the
`
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`
`
`solubility or dispersibility of one component in the other by
`
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`
`at least 1% (absolute) by weight of the lubricant/refrigerant
`
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`
`composition. Preferably, the surfactant used increases the
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`solubility or dispersibility of one component in the other by
`
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`at least 2 weight % (absolute), and even more preferably by
`
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`at least 5 weight % (absolute). For example, a composition
`
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`
`
`of Refrigerant A and Lubricant B is a single phase compo-
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`
`sition when it comprises up to and including, but no more
`
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`
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`than, 10% by weight of composition of Refrigerant A. With
`
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`the addition of a Surfactant C, the same composition remains
`
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`as a single phase composition up to and including 15% by
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`
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`weight of the composition of Refrigerant A. For the purposes
`
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`
`
`
`
`of the present
`invention, surfactant C is considered to
`
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`
`
`increase the solubility of Refrigerant A in Lubricant B by 5
`wt. %.
`
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`
`In certain preferred embodiments,
`the surfactant used
`
`
`
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`
`
`increases the solubility and/or dispersibility of the refriger-
`
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`
`
`ant in the hydrocarbon-based lubricant and increases the
`
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`
`
`solubility and/or dispersibility of the hydrocarbon-based
`
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`
`
`lubricant in the refrigerant. Although applicants do not wish
`
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`
`
`to be bound by or to any theory of operation, it is believed
`
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`that the surfactant in such embodiments enhances solubility
`
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`
`tension
`and/or dispersibility by reducing the interfacial
`
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`between the two liquid layers. Typically,
`in such
`
`
`4
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`
`
`embodiments,
`is soluble in the lubricant.
`the surfactant
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`According to certain preferred embodiments, the surfactant
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`
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`is soluble in both the refrigerant and the lubricant.
`
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`
`Examples of surfactants suitable for use in the present
`
`
`
`
`
`
`
`
`invention are disclosed in U.S. Pat. No. 5,254,280, issued to
`
`
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`
`
`
`
`Thomas et al. and incorporated herein by reference, and
`
`
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`
`
`include: sulfonates;
`long-chain alkyl substituted aromatic
`
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`
`
`sulfonic acids; phosphonates; thiophosphonates; phenolates;
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`metal salts of alkyl phenols; alkyl sulfides; alkylphenolal-
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`
`
`dehyde condensation products; metal salts of substituted
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`salicylates; N-substituted oligomers or polymers from the
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`reaction products of unsaturated anhydrides and amines.
`
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`Other suitable surfactants include: polyoxyethylene-type
`
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`
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`nonionic surfactants, such as polyoxyethylene alkyl ethers,
`
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`
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`polyoxyethylene alkenyl ethers, polyoxyethylene aryl
`
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`
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`ethers, polyalkylaryl ethers, polyoxyethylene fatty acid
`
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`esters, polyoxyethylene sorbitan fatty acid esters and poly-
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`oxyethylene sorbitol fatty acid esters; copolymers of meth-
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`acrylates with N-substituted compounds, such as N-vinyl
`
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`pyrrolidone or dimethylaminoethyl methacrylate; copoly-
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`
`
`mers which incorporate polyester linkages, such as vinyl
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`acetate-maleic anhydride copolymers; and the like. The
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`alkyl groups of the polyoxyethylene alkyl ethers are pref-
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`erably straight-chain or branched alkyl groups having from
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`
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`about 1 to about 15 carbon atoms which may, optionally, be
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`further substituted with fluorine. The aryl groups of the
`
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`Polyoxyethylene aryl ethers are preferably aromatic groups
`
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`
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`having from about 6 to about 20 carbon atoms. Such
`
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`
`
`aromatic groups may, optionally, be further substituted with
`
`
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`
`
`fluorine. According to certain preferred embodiments, the
`
`
`
`
`surfactant is a polyoxyethylene alkyl ether.
`
`
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`
`
`Although applicants do not wish to be bound by or to any
`
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`
`
`theory of operation, it is believed that solubilizing agents
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`
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`according to the present invention act as carriers for the
`
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`
`
`surfactant and aid the surfactant in enhancing the miscibility
`
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`
`
`of hydrocarbon-based lubricants and refrigerants. In certain
`
`
`
`
`
`
`
`embodiments of the present
`invention,
`the surfactant
`is
`
`
`
`
`
`
`readily soluble in hydrocarbon-based lubricants but signifi-
`
`
`
`
`
`
`cantly less soluble in refrigerants. Accordingly, a solubiliz-
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`
`
`
`ing agent which is relatively soluble in both hydrocarbon-
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`
`
`based lubricants and refrigerants, and in which a surfactant
`
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`
`
`of the present
`invention in soluble, can be used to aid
`
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`
`
`transport of the surfactant between lubricant and refrigerant
`
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`to enhance the miscibility thereof. It is further believed that
`
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`
`
`both the surfactant and the solubilizing agent independently
`
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`
`
`
`enhance the solubility and dispersibility of the refrigerant in
`the lubricant.
`
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`
`
`Any of a wide range of solubilizing agents can be used in
`
`
`
`
`
`
`
`the present invention. Suitable solubilizing agents include
`
`
`
`
`
`
`
`polyalkylene glycol
`lubricants such as straight-chain or
`
`
`
`
`
`
`branched polypropylene glycols, polybutylene glycols, and
`
`
`
`
`
`
`random or ordered copolymers of ethylene oxide, propylene
`
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`
`
`
`oxide, and/or butylene oxide in any combination. The poly-
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`alkylene glycols may have terminal hydroxyl groups and/or
`
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`
`
`terminal moieties for capping one or more ends of the
`
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`
`
`molecule. Suitable moieties for capping polyalkylene glycol
`
`
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`
`
`
`of the present invention include: fluorinated alkyl or aryl
`
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`
`
`
`groups; non-fluorinated alkyl or aryl groups; ester groups,
`
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`
`and mixtures thereof. In addition, ester and diester lubricants
`
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`
`
`based on acids having straight-chain or branched chains of
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`
`
`from about 3 to about 15 carbon atoms and alcohols such as,
`
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`
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`
`
`
`for example, pentaerythritol, neopentyl glycol, glycerin, or
`
`
`
`
`
`
`
`trimethylolpropane are suitable for use as solubilizing agents
`
`
`
`
`
`
`
`
`
`in the present invention. Polyvinyl ethers (PVEs) are also
`
`
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`
`
`
`suitable as solubilizing agents. PVEs are characterized gen-
`
`
`
`
`erally by the formula —[CH2CHOR1 n—[CH2CHOR2]m—
`
`
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`
`
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`
`
`wherein R1 and R2 are independently aromatic or alkyl
`
`US 6,516,837 B2
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`10
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`15
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`20
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`25
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`30
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`35
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`40
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`45
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`50
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`55
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`60
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`65
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`Page 3 of 5
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`Page 3 of 5
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`

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`6
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`solubilizing agent per 100 parts by weight of hydrocarbon-
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`based lubricant, and even more preferably, from about 5 to
`
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`
`
`about 20 parts by weight of solubilizing agent per 100 parts
`
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`by weight of hydrocarbon-based lubricant.
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`The weight ratio of surfactant to hydrocarbon-based lubri-
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`cant is preferably from about 0.01 to about 10 parts by
`
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`
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`weight of surfactant per 100 parts by weight of hydrocarbon-
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`based lubricant, and even more preferably, from about 1 to
`
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`
`
`about 5 parts by weight of surfactant per 100 parts by weight
`
`
`
`of hydrocarbon-based lubricant.
`
`
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`
`
`
`
`
`Any of a wide range of methods for introducing the
`
`
`
`
`
`refrigerant composition to a refrigeration system comprising
`
`
`
`
`
`
`
`
`a hydrocarbon-based lubricant can used in the present inven-
`
`
`
`
`
`
`
`
`tion. For example, one method comprises attaching a refrig-
`
`
`
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`
`
`
`erant container to the low-pressure side of a refrigeration
`
`
`
`
`
`
`
`system and turning on the refrigeration system compressor
`
`
`
`
`
`
`
`
`
`to pull the refrigerant into the system. In such embodiments,
`
`
`
`
`
`
`
`
`the refrigerant container may be placed on a scale such that
`
`
`
`
`
`
`
`the amount of refrigerant composition entering the system
`
`
`
`
`
`
`
`can monitored. When a desired amount of refrigerant com-
`
`
`
`
`
`
`
`
`position has been introduced into the system, charging is
`
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`
`
`
`stopped. Alternatively, a wide range of charging tools,
`
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`
`
`
`
`
`
`known to those of skill in the art, are commercially avail-
`
`
`
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`
`
`
`able. Accordingly, in light of the above disclosure, those of
`
`
`
`
`
`
`
`
`skill in the art will be readily able to introduce non-chlorine
`
`
`
`
`
`
`compositions into refrigeration systems according to the
`
`
`
`
`
`present invention without undue experimentation.
`EXAMPLES
`
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`
`In order to illustrate, in a non-limiting manner, the present
`
`
`
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`
`
`
`invention is described in connection with the following
`
`
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`
`
`
`
`examples of the present method and comparative example.
`
`Example 1
`
`
`
`
`
`
`
`The following example illustrates a use of the present
`
`
`
`
`method with an air-conditioning system.
`
`
`
`
`
`From an air-conditioning system containing chlorodifluo-
`
`
`
`
`
`
`
`romethane (“R-22”) and mineral oil is removed the R-22. A
`
`
`
`
`
`
`mixture of R-407C, polybutylene glycol and a surfactant is
`
`
`
`
`
`
`
`
`made. The mixture is added to the system. The system
`
`
`
`
`
`
`
`operates in satisfactory manner. The capacity of the system
`
`
`
`
`
`
`
`
`is within 10% of the capacity of a system comprising a
`mixture of R-407C and an ester lubricant. This indicates that
`
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`
`
`
`there are no oil return problems.
`
`
`
`
`
`
`Example 2
`
`
`
`
`
`
`
`The following example illustrates a use of the present
`
`
`
`
`method with an air-conditioning system.
`
`
`
`
`
`From an air-conditioning system containing chlorodifluo-
`
`
`
`
`
`
`
`romethane (“R-22”) and mineral oil is removed the R-22. A
`
`
`
`
`
`
`mixture of R-407C, PGB 503 (a polybutylene glycol having
`
`
`
`
`
`
`
`a molecular weight of 503 and a viscosity of 45 centistokes
`
`
`
`
`
`
`
`
`at 37° C.), and Brij 97 (C18H35(OCH2CH2)nOH, wherein n
`
`
`
`
`
`
`
`
`
`is about 2) is made. The mixture is added to the system. The
`
`
`
`
`
`
`
`system operates in satisfactory manner. The capacity of the
`
`
`
`
`
`
`
`system is within 10% of the capacity of a system comprising
`a mixture of R-407C and an ester lubricant. This indicates
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`that there are no oil return problems.
`
`Example 3
`
`
`
`
`
`
`
`The following example illustrates a use of the present
`
`
`
`
`method with an air-conditioning system.
`
`
`
`
`
`From an air-conditioning system containing chlorodifluo-
`
`
`
`
`
`
`
`romethane (“R-22”) and mineral oil is removed the R-22. A
`
`
`
`
`
`US 6,516,837 B2
`
`
`
`
`5
`
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`
`
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`
`
`groups containing from about 1 to about 15 carbon atoms
`
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`
`
`
`with at least one of m or n being non-zero and ranging from
`
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`
`
`
`
`
`
`
`
`3 to 20. PVEs suitable for use in the present invention may
`
`
`
`
`
`
`optionally be substituted with fluorine or heteroatoms such
`
`
`
`
`
`
`
`
`as oxygen, nitrogen and sulfur.
`In certain preferred
`
`
`
`
`
`
`embodiments, the solubilizing agent is a polyalklene glycol
`
`
`
`
`
`
`
`
`
`having more units derived from butylene oxide than propy-
`
`
`
`
`
`
`
`
`
`lene oxide, and no more than 10 mole percent of ethylene
`
`
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`
`
`
`
`
`oxide. In certain other preferred embodiments, the solubi-
`
`
`
`
`
`
`
`lizing agents are polybutylene glycols having terminal
`
`
`
`
`
`hydroxyl groups or straight-chain or branched polybutylene
`
`
`
`
`
`
`
`
`
`glycols having organic caps on one or more ends of the
`
`
`
`
`
`
`
`
`molecule, such as those disclosed in U.S. Pat. No. 5,154,
`
`
`
`
`
`
`
`
`incorporated herein by reference.
`In certain more
`846,
`
`
`
`
`
`
`preferred embodiments, the solubilizing agent is a straight-
`
`
`
`
`
`
`
`chain or branched polybutylene glycol having terminal
`
`
`hydroxyl groups.
`
`
`
`
`
`
`
`
`The viscosity of the solubilizing agents used in the present
`
`
`
`
`
`
`
`
`invention may comprise any viscosity suitable for a particu-
`
`
`
`
`
`
`
`
`lar application. In certain preferred embodiments, the vis-
`
`
`
`
`
`
`
`
`cosity of the solubilizing agent used in the present invention
`is from about 1 to about 20 centistokes at 100° C. More
`
`
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`
`
`
`
`
`
`
`
`
`
`
`
`
`preferably, the solubilizing agent has a viscosity of from
`
`
`
`
`
`
`
`
`
`about 1 to about 10 centistokes at 100° C., and even more
`
`
`
`
`
`
`
`preferably from about 1 to about 5 centistokes at 100° C.
`
`
`
`
`
`
`
`Procedures for preparing polyalkylene glycols suitable for
`
`
`
`
`
`
`
`
`
`use in the present invention are well known. For example,
`
`
`
`
`
`
`
`
`U.S. Pat. No. 5,254,280, discloses methods for preparing
`
`
`
`
`
`
`
`polybutylene glycols having fluorinated alkyl group caps. A
`30
`
`
`
`
`
`
`
`
`wide variety of polyalkylene glycol
`lubricants are also
`
`
`
`
`
`
`commercially available, for example, polypropylene glycols
`
`
`
`
`
`
`
`and polybutylene glycols having terminal hydroxyl groups
`are available form Dow Chemical. Various ester-based lubri-
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`
`cants are also available commercially,
`including,
`for
`
`
`
`
`
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`example, Mobil EAL 22, an ester lubricant having a viscos-
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`ity of 32 centistokes at 37° C., available commercially from
`Exxon-Mobil.
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`In addition to the refrigerant, surfactant and solubilizing
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`agent,
`the composition introduced into the hydrocarbon-
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`based lubricant according to the present
`invention can
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`include other additives or materials of the type used in
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`refrigerant compositions to enhance their performance in
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`refrigeration systems. For example,
`the composition can
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`include also extreme pressure and antiwear additives, oxi-
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`dation and thermal stability improvers, corrosion inhibitors,
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`viscosity index improvers, pour and floc point depressants,
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`antifoaming agents,
`lubricants soluble in both the
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`hydrocarbon-based lubricant and non-chlorine-containing
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`refrigerant, viscosity adjusters and the like. Examples of
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`such additives are disclosed in U.S. Pat. No. 5,254,280.
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`Any suitable amounts of the refrigerant, surfactant and
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`solubilizing agent can be used in the practice of the present
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`invention. In general, the weight ratio of hydrocarbon-based
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`to non-chlorine-containing refrigerant
`lubricant
`is from
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`about 0.1 to about 60 parts by weight of lubricant per 100
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`parts by weight of refrigerant. Preferably, the amount of
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`hydrocarbon-based lubricant
`to non-chlorine-containing
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`refrigerant is from about 15 to about 50 parts by weight of
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`lubricant per 100 parts by weight of refrigerant, and even
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`more preferably, from about 15 to about 30 parts by weight
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`of lubricant per 100 parts by weight of refrigerant.
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`to
`Furthermore the weight ratio of solubilizing agent
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`hydrocarbon-based lubricant is preferably from about 1 to
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`about 50 parts by weight of solubilizing agent per 100 parts
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`by weight of hydrocarbon-based lubricant, and more
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`preferably, from about 5 to about 30 parts by weight of
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`10
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`15
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`20
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`25
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`35
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`45
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`50
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`55
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`60
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`65
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`Page 4 of 5
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`Page 4 of 5
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`US 6,516,837 B2
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`8
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`5
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`What is claimed is:
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`1. A method of recharging a refrigeration system of the
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`type containing a chlorine-containing refrigerant and a
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`lubricant, comprising the steps of:
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`(a) removing said chlorine-containing refrigerant from
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`said refrigeration system while leaving a substantial
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`portion of said lubricant in said system; and
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`(b) introducing to said lubricant