Compositions – Vaporization – or expansion – refrigeration or heat or energy... – With lubricants – or warning – stabilizing or anti-corrosion...
Reexamination Certificate
1999-05-21
2002-11-12
Einsmann, Margaret (Department: 1751)
Compositions
Vaporization, or expansion, refrigeration or heat or energy...
With lubricants, or warning, stabilizing or anti-corrosion...
C508S579000, C508S583000, C252S067000
Reexamination Certificate
active
06478983
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a lubricating oil for a compression refrigerating machine, which is used together with a hydrofluorocarbon refrigerant and a refrigerating/air-conditioning machine using the same.
BACKGROUND ART
Many attempts have hitherto been made to prevent choking phenomena in capillary tubes and expansion valves caused by contaminants generated by changing refrigerant systems from hydrochlorofluorocarbon (HCFC) to hydrofluorocarbon (HFC). For example, in “Refrigerator and Refrigerant Compressor” disclosed in JP-A 103616/1995, a filter composed of a membrane material, such as fluororesin and cellulose mixed ester, is used in a refrigerant passage. In addition, in “Refrigerator and Refrigerant Compressor” disclosed in JP-A 235569/1994, a filter composed of a porous sintered metal and having a pore size of not more than 80 &mgr;m is inserted in a dryer of a refrigerating machine. Further, in “Refrigerator” disclosed in JP-A 105673/1996, the removal of sludge is performed by blowing capillary tubes with a high-pressure gas during the operation.
In addition, in “Refrigerating Cycle” disclosed in JP-A 247582/1996, in order to prevent various kinds of harm caused by the accumulation of contaminants generated during refrigerating cycling,
(1) a plurality of mechanisms provided with a tube charged with a filler or a branching valve for dividing a refrigerant passage are used as a throttling mechanism; and
(2) a scavenging tube is provided through a directional control valve apart from a regular passage, or
(3) a synthetic ester oil and a mineral oil of any one of a naphthene mineral oil, a paraffin mineral oil and an alkyl benzene mineral oil are used at a specified ratio as a lubricating oil for a compressor. Further, in “Refrigerator Composition and Refrigerating Cycle” disclosed in JP-A 143486/1997, a refrigerating machine oil containing a base oil composed of a mixture of 5-30 parts by weight of any one of mineral oils of a naphthene mineral oil, a paraffin mineral oil, a poly &agr;-olefin mineral oil and an alkylbenzene mineral oil, and 70-95 parts by weight of polyol ester is used in order to prevent the choking phenomenon caused by an ester refrigerating machine oil.
However, in the cases of “Refrigerator and Refrigerant Compressor” disclosed in JP-A 103616/1995, “Refrigerator and Refrigerant Compressor” disclosed in JP-A 235569/1994, “Refrigerator” disclosed in JP-A 105673/1996, and “Refrigerating Cycle” disclosed in JP-A 247582/1996, there is a problem that a filter, a high-pressure gas blower, a throttling mechanism charged with a filler, and a tube for scavenging contaminants are additionally required since the previous refrigerators and air conditioners can not be used as they are, leading to an increased cost. In addition, when the aforementioned filters are utilized, there arises a further problem that the filters themselves are clogged.
In addition, in the cases of “Refrigerating Cycle” disclosed in JP-A 247582/1996 and “Refrigerator Composition and Refrigerating Cycle” disclosed in JP-A 143486/1997, the above refrigerating machine oil has bad miscibility with HFC refrigerants and, especially in the case of R410A, there is a problem that an amount thereof to be mixed is highly restricted. Further, there is also a problem that, depending upon the operating conditions, the occurrence of deflection in the ratio of the mixed oil within the refrigerating machine reduces the efficiency for washing capillary tubes.
DISCLOSURE OF THE INVENTION
The present invention was done to overcome the above previous drawbacks. It is an object of the present invention to provide a lubricating oil, which can prevent choking caused by contaminants in capillary tubes and expansion valves in the use of a HFC refrigerant, for a compression refrigerating machine without any modification of the machine, and a refrigerating/air-conditioning machine using the same.
In order to attain the above object, the present invention features a lubricating oil for a compression refrigerating machine, used together with a HFC refrigerant, which comprises a compound having the following general formula:
R
1
(R
2
O)
n
(R
3
O)
m
R
4
wherein R
1
: any one of alkyl group, alkoxy group and aryl group;
R
2
: alkylene group having a carbon number of 2-4;
R
3
: alkylene group having a carbon number of 2-4;
R
4
: hydrogen or alkyl group.
In this essential feature, a compound having the miscibility with a HFC refrigerant and the solubility with contaminants generated in the use of the HFC refrigerant is added to the present lubricating oil for a compression refrigerating machine. Therefore, the deflection in the ratio between the present lubricating oil and the HFC refrigerant within the above refrigerating/air-conditioning machine is not caused by using the present lubricating oil together with a HFC refrigerant as a working fluid for a compression refrigerating machine. Therefore, the reduction in the efficiency for washing capillary tubes and expansion valves can be prevented. That is, according to the present invention, the reliability of the refrigerating/air-conditioning machine using the HFC refrigerant may be enhanced without any modification thereof.
In addition, the present invention features a polyvinyl ether lubricating oil for a compression refrigerating machine, used together with a HFC refrigerant, which comprises a compound added at an amount of not less than 5 wt % and not more than 10 wt %, said compound having the following general formula:
R
1
(C
4
H
8
O)
n
(R
5
O)
m
R
4
wherein R
1
: any one of alkyl group, alkoxy group and aryl group;
R
4
: hydrogen or alkyl group;
R
5
: alkylene group having a carbon number of 2-3;
n/m: 1/9-10/0.
In this essential feature, since the above compound contains butylene oxide (C
4
H
8
O) having a carbon number of 4, the solubility with the HFC refrigerant and the contaminants is very good. Moreover, the compound is added to the present polyvinyl ether lubricating oil for a compression refrigerating machine at an amount of not less than 5 wt %. Therefore, the rate of flow reduction caused by choking in the capillary tubes, expansion valves and the like of a refrigerating/air-conditioning machine using the present lubricating oil and the HFC refrigerant as a working fluid, can be sufficiently decreased to 0%-10%, and the choking caused by contaminants in capillary tubes and expansion valves can be effectively prevented. Further, since the amount of the above compound to be added to the present lubricating oil is not more than 10 wt %, the reduction in volume insulation resistance for the present lubricating oil as a whole can be decreased. Therefore, it is not possible that leakage current from a hermetic motor increases. That is, according to the present invention, the reliability of the refrigerating/air-conditioning machine using a HFC refrigerant may be enhanced without any modification thereof.
In addition, the present invention features a refrigerating/air-conditioning machine equipped with a compressor using a HFC refrigerant and a lubricating oil as a working fluid, which comprises a compound having the following general formula:
R
1
(R
2
O)
n
(R
3
O)
m
R
4
wherein R
1
: any one of alkyl group, alkoxy group and aryl group;
R
2
: alkylene group having a carbon number of 2-4;
R
3
: alkylene group having a carbon number of 2-4;
R
4
: hydrogen or alkyl group.
In this essential feature, there is used, as a working fluid for a compressor of a refrigerating/air-conditioning machine, a lubricating oil with an added compound together with a HFC refrigerant, said compound has the miscibility with the HFC refrigerant and the solubility with contaminants generated in the use of the HFC refrigerant. Therefore, the deflection is not caused in the ratio between the above lubricating oil and the HFC refrigerant, and, consequently, the reduction in the efficiency for washing capillary tubes and expansion valves can be prevented. That is, according to the present invention, a high-reliable refrigerating/air-conditioning machine using a HFC refrig
Matsuura Hideki
Nomura Masaki
Birch & Stewart Kolasch & Birch, LLP
Daikin Industries Ltd.
Einsmann Margaret
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