Refrigeration – Refrigeration producer – With lubricant handling means
Reexamination Certificate
1999-01-25
2002-04-23
Einsmann, Margaret (Department: 1751)
Refrigeration
Refrigeration producer
With lubricant handling means
C062S471000, C062S502000, C062S192000, C252S068000
Reexamination Certificate
active
06374629
ABSTRACT:
FIELD OF THE INVENTION
This invention is directed to a compression heat transfer system containing refrigerants and lubricants wherein there is partial to near immiscibility of one in the other at above a certain temperature. The lubricant or lubricant-rich phase (where there is some miscibility of the lubricant and refrigerant) resides on the bottom of the refrigerant or refrigerant-rich phase (where there is some miscibility of the lubricant and refrigerant).
BACKGROUND OF THE INVENTION
Compression heat transfer system designers must consider lubricant circulation and return of the lubricant to a sump or reservoir when designing and evaluating a refrigeration system. The primary function of the lubricant is to lubricate and seal compressor components. In some applications, such as an oil flooded rotary screw compressor, the lubricant also functions as a heat transfer medium, removing the heat of compression. Design of the refrigeration system must include a method to keep the majority of the lubricant in the compressor, and to provide a means to return, in an efficient manner, the oil which has entered the refrigeration system back to the reservoir.
Chlorofluorocarbon compounds, generally referred to in the industry as CFCs are comprised entirely of carbon, chlorine and fluorine, but no presence of hydrogen atoms. Molecules that also contain hydrogen are designated as HCFCs. Molecules containing only carbon, hydrogen and fluorine, but no presence of chlorine, are designated as HFCs.
U.S. Pat. No. 4,851,144 (McGraw et al., Jul. 25, 1989) relates to lubricant base compositions for compression refrigeration that are composed of 95 to 5% by weight of polyether polyols having a number average molecular weight from about 400 to about 5,000 and 5 to 95% of esters made from polyhydric alcohols with alkanoic acids or esters made from alkanedioic acids with alkanols. A refrigeration fluid is made from the base composition with the addition of selected hydrochlorofluorocarbons and hydrofluorocarbons so that the base composition is miscible with the refrigerant in the range from −20° C. to greater than 65° C.
U.S. Pat. No. 4,948,525 (Sasaki et al., Aug. 14, 1990) discloses a lubricating oil composition for a refrigerator using therein 1,1,1,2-tetrafluoroethane as the refrigerant, comprising as the base oil a polyoxyalkylene glycol monoether of the following general formula
R
1
—(OR
2
)
m
—OH
wherein R
1
is an alkyl group having 1-18 carbon atoms, m is an integer of 5-70, R
2
is an alkylene group having 2-4 carbon atoms and a ratio of 0-0.8 between (the number of —OR
2
— group wherein R
2
is ethylene group)/m in the molecule, the polyoxyalkylene glycol monoether having a specified pour point and a specified kinematic viscosity. In one embodiment, the lubricating oil composition may further comprise a specified phosphate and at least one kind of a specified epoxy compound to further improve the oil composition in properties.
U.S. Pat. No. 5,027,606 (Short, Jul. 2, 1991) relates to a rotary displacement compression heat transfer system and method for improving its efficiency which includes a rotary displacement compressor for compressing a refrigerant, a condenser connected with the outlet of the compressor, an evaporator connected with the inlet of the compressor, an oil pump for injecting oil into the compressor, an oil separator for separating out the oil and recirculating it to the compressor, a non-chlorinated hydrocarbon refrigerant, and a synthetic oil ingredient in the oil providing an inverse solubility characteristic where a mixture of the refrigerant and oil has two immiscible phases in the compressor's operating temperature range and has only one dissolved liquid phase at a temperature in the evaporator's operating range at a weight concentration of oil less than about 5%.
U.S. Pat. No. 5,185,092 (Fukuda et al., Feb. 9, 1993) describes a lubricating oil for refrigerators using 1,1,1,2-tetrafluoroethane refrigerant. Having esters as base oil, its viscosity range is between 2-30 mm/s at 100° C. By adding esters alone or by adding esters having different viscosity to esters base oil, or by adding polymer, the viscosity is adjusted to obtain the lubricating oil suitable for various types of refrigerators. The lubricating oil thus obtained has excellent compatibility with 1,1,1,2-tetrafluoroethane refrigerant, which is an alternative to freon, and has low hygroscopic property and high heat-resistant property.
By reducing the total acid number to 0.05 mg KOH/g or less, the corrosion resistant property and insulating property of lubricating oil are not decreased, and the lubricating oil for refrigerator having high refrigerant stability, hydrolytic stability and insulating property can be obtained.
Further, by adding sulfur type anti-wear agent, the better anti-wear effect of the lubricating oil can be obtained on iron/aluminum contact portion in the refrigerator.
U.S. Pat. No. 5,211,884 (Bunemann et al., May 18, 1993) describes a lubricant/working fluid composition for use in mechanical vapor compression type heat transfer devices wherein the working fluid is preferably tetrafluoroethane and the lubricant is an ester which is miscible with the working fluid at 10% over a temperature range of −50° C. to +80° C., and has a viscosity of 5 to 100 cSt at 40° C. Useful esters include pentaerythritol partial ester of straight chain C
5
or branched chain C
7
carboxylic acids. The esters are compatible with non-chlorine containing working fluids and exhibit a low level of corrosion.
U.S. Pat. No. 5,254,280 (Thomas et al., Oct. 19, 1993) is directed to polyoxyalkylene glycols which are used to flush currently used lubricants such as mineral oil, alkyl benzenes, and esters from a refrigeration system for conversion to fluorocarbon or hydrofluorocarbon refrigerants. The polyoxyalkylene glycol is selected from the group consisting of polyoxyalkylene glycol which is at least difunctional with respect to hydroxyl groups, polyoxyalkylene glycol having an alkyl cap on one end thereof, and polyoxyalkylene glycol having at least two alkyl caps. The polyoxyalkylene glycol has a molecular weight of about 300 to 4,000, has a viscosity of about 5 to 150 centistokes at 37° C., and is made from alkylene oxide having at least 4 carbon atoms.
U.S. Pat. No. 5,369,287 (Sunaga et al., Nov. 29, 1994) relates to 1,1,1,2-tetrafluoroethane used in a refrigerator as the refrigerant, while a polyolester oil which is well compatible with the refrigerant is used as the base oil and a phenolic antioxidant, a specified amine and a phosphoric triester are added thereto to give a refrigerator oil composition. Thus the hydrolysis of the polyolester oil can be prevented to thereby protect the sliding members such as a roller and a vane from the corrosion and wear which are caused by the hydrolysis.
U.S. Pat. No. 5,395,544 (Hagihara et al., Mar. 7, 1995) is directed to a working fluid composition for a refrigerating machine which contains difluoromethane and a refrigeration oil. An ester formed between (a) an aliphatic polyhydric alcohol having a carbon number of 2 to 12; and (b) a saturated aliphatic monocarboxylic acid having a carbon number of 4 to 9 or a derivative thereof, the ratio of the number of acyl groups having a branched chain or branched chains to the number of the entire acyl groups in the ester being not less than 95%, is used as a base oil of the refrigeration oil. The working fluid composition for refrigerating machine of the present invention is excellent not only in compatibility, lubricity, and electric insulating property but also in thermal stability as compared to the conventional products.
U.S. Pat. No. 5,403,503 (Seiki et al., Apr. 4, 1995) discloses a refrigerator oil composition for hydrogen-containing hydrofluorocarbons (hydrogenated Flon compound) refrigerant which comprises a polyoxyalkylene glycol derivative and/or a specific polyester compound, which are/is compounded with (a) an aliphatic acid partially esterified with a polyhydric alcohol and (b) a phosphate co
Oberle Jill Ellen
Rajewski Thomas Edward
Einsmann Margaret
Esposito Michael F.
Laferty Samuel B.
The Lubrizol Corporation
LandOfFree
Lubricant refrigerant composition for hydrofluorocarbon... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Lubricant refrigerant composition for hydrofluorocarbon..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Lubricant refrigerant composition for hydrofluorocarbon... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2899493