Compositions – Vaporization – or expansion – refrigeration or heat or energy... – With lubricants – or warning – stabilizing or anti-corrosion...
Reexamination Certificate
1999-12-02
2001-07-10
Diamond, Alan (Department: 1753)
Compositions
Vaporization, or expansion, refrigeration or heat or energy...
With lubricants, or warning, stabilizing or anti-corrosion...
C062S474000, C062S114000, C062S084000, C062S115000, C062S118000, C508S485000, C508S492000, C508S493000, C417S410300, C417S902000, C418S083000, C418S097000, C418S094000, C418S098000, C418S178000, C418S099000
Reexamination Certificate
active
06258293
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a refrigeration cycle and refrigerant compressor, and it relates to, in particular, a refrigeration-cycle-constituting material system comprising a refrigerating machine oil composition suitable for a flon type refrigerant containing no chlorine and having a critical temperature of 40° C. or higher, for example, flon
134
a,
and electrical insulating materials and a drying agent which are hardly deteriorated by the refrigerating machine oil composition.
2. Prior Art
In recent years, chlorine-containing flons (chlorofluorocarbons, abbreviated as CFC) have been included in the list of compounds under regulation in use, all over the world because of the problems of environmental pollution, in particular, the ozone depletion and the global warming.
All of flons included in the list of compounds under regulation in use are chlorine-containing flons such as flon
11
, flon
12
, flon
113
, flon
114
, flon
115
, etc. Flon
12
which has been exclusively used as a refrigerant in refrigerating apparatus such as refrigerators, dehumidifiers, etc., has also been included in the list.
Therefore, a refrigerant usable in place of flon
12
is required. Hydrofluorocarbon (HFC) having a low reactivity with ozone and a short decomposition period in the air has recently been noted as a substitute refrigerant. Flon
134
a
(1,1,1-tetrafluoroethane, CH
2
FCF
3
) is a typical example of such a refrigerant. In detail, when the ozone depletion potential (ODP) of flon
12
(dichlorodifluoromethane CCl
2
F
2
) is taken as 1, that of flon
134
a
is zero. When the global warming potential (GWP) of flon
12
is taken as
1
, that of flon
134
a
is 0.3 or less. Flon
134
a
is noncombustible and similar to flon
12
in thermal properties such as temperature-pressure characteristics. Therefore, flon
134
a
has been said to be advantageous in that it can be put into practical use without greatly changing the structures of refrigerating apparatus such as refrigerators and dehumidifiers and refrigerant compressors in which flon
12
has heretofore been used.
Flon
134
a,
however, has a unique chemical structure and hence very characteristic properties. Therefore, it has a very poor compatibility with refrigerating machine oils such as mineral oils and alkylbenzene oils which have been used in conventional refrigeration system using flon
12
, and hence it cannot be put into practical use at all. In addition, the suitability including the improving effect on the lubrication and the resistance to frictional wear of the sliding portions of compression mechanical parts, the influence on electrical insulating materials, the influence on drying agents, etc. is a problem, and there has been an eager desire for the development of a novel material system constituting a compressor and a refrigerating apparatus.
Therefore, before referring to the problem of the miscibility of a refrigerant with a refrigerating machine oil, conventional refrigerant compressor and refrigeration apparatus which use a flon type refrigerant are first explained with reference to
FIG. 7
to FIG.
9
.
FIG. 7
is a vertical cross-sectional view of the principal part of a conventional closed rotary compressor.
FIG. 8
is a cross-sectional view for explaining the displacement volume of the compressor section of the compressor.
FIG. 9
is a diagram showing the structure of an ordinary refrigeration cycle.
In
FIG. 7
, numeral
1
shows a case used both as a closed container and as a oil pan. In the case
1
, an electric motor section
22
and a compressor section
23
are accommodated.
The electric motor
22
is composed of a stator
19
and a rotor
20
, and a rotating shaft
4
A made of cast iron is fitted in the rotor
20
. The rotating shaft
4
A has an eccentric portion
3
and an shaft hole
17
is formed in hollow form on the one side of the eccentric portion
3
.
The core wire of the winding wire portion
19
a
of the stator
19
is coated with an ester imide film, and an electrical insulating film of a polyethylene terephthalate is inserted between the core portion and the winding wire portion of the stator. The rotor
4
A has a surface finished by grinding.
The compressor
23
has as its chief mechanism components a cylinder
2
made of an iron-based sintered product; a roller
7
made of cast iron which is fitted in the eccentric portion
3
of the rotating shaft
4
A and eccentrically rotated along the inside of the cylinder
2
; a high-speed steel vane which is reciprocated in the groove
8
of the cylinder
2
while one side of the vane is in contact with the roller
7
and the other side is pushed by a spring
9
; and a main bearing
5
and a sub-bearing
6
which are made of cast iron or an iron-based sintered product, are provided on both ends of the cylinder, and serve both as bearings for the rotary shaft
4
A and as the side wall of the cylinder
2
.
The sub-bearing
6
has a discharge valve
27
, and a discharge cover
25
is attached thereto so as to form a silencer
28
. The main bearing
5
, the cylinder
2
and the sub-bearing
6
are fastened with a bolt
21
.
A pump chamber
12
is composed of a space and parts surrounding the space, i.e., the back of the vane
10
, the groove
8
of the cylinder
2
, the main bearing
5
and the sub-bearing
6
.
The main bearing
5
has a suction piece
14
which can suck a naphthene type or alkylbenzene type refrigerating machine oil
13
A in which a refrigerant flon gas stored in the bottom of the case
1
has been dissolved, into the pump chamber
12
. The sub-bearing
6
has a discharge port
16
which can discharge the refrigerating machine oil
13
A to an oil tube
15
from the pump chamber
12
. The oil tube
15
is designed to be able to supply the refrigerating machine oil
13
A to the shaft hole
17
of the rotating shaft
4
A and then to predetermined sliding portions from the shaft hole
17
through a branch opening
18
.
The action of the rotary compressor thus composed is explained below with reference to
FIGS. 7 and 8
. When the compressor is operated to rotate the rotating shaft
4
A made of cast iron, a roller
7
made of tempered cast iron is rotated with the rotation of rotating shaft
4
A, and the high-speed steel vane
10
is reciprocated in the groove
8
of the cylinder
2
made of cast iron or a iron-based sintered product while the vane
10
is pushed by the spring
9
and its end is in contact with the roller
7
. Thus, the vane
10
compresses a refrigerant (flon
12
) which has flown in through a refrigerant suction opening (not shown), and the refrigerant is discharged outside the compressor from a discharge pipe
29
through a refrigerant discharge opening
24
. The winding wire portion
19
a
and the electrical insulating film (not shown) of the stator
9
are immersed in the refrigerating machine oil containing flon dissolved therein, or they are exposed to circumstances of spraying with mist of the refrigerant oil.
In the case of a combination of a conventional refrigerating machine oil consisting of a mineral oil or an alkylbenzene and flon
12
, flon
12
is completely miscible with the refrigerating machine oil in all use ranges, so that it has been not necessary at all to care about the various problems concerning the miscibility of flon
134
a
with a refrigerating machine oil which are hereinafter described in detail, namely, the separation into two layers between the refrigerating machine oil and the refrigerant in a compressor, and the residence of the refrigerating machine oil in a heat exchanger. However, in the case of fluorohydrocarbon type refrigerants containing no chlorine which have unique characteristics, for example, flon
134
a,
the miscibility of the refrigerant with a refrigerating machine oil is the most serious problem in practice because there is no practical refrigerating machine oil which can easily dissolve the refrigerant.
In general, for improving the performance characteristics of a compressor, namely, the coefficient of perfo
Fukuda Katsumi
Hata Hiroaki
Homma Yoshiharu
Iizuka Tadashi
Iwata Hiroshi
Antonelli Terry Stout & Kraus LLP
Diamond Alan
Hitachi , Ltd.
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