Refrigeration – Processes – Assembling – charging – or repairing of refrigeration producer
Reexamination Certificate
2000-05-17
2003-01-28
Jiang, Chen-Wen (Department: 3744)
Refrigeration
Processes
Assembling, charging, or repairing of refrigeration producer
C062S292000
Reexamination Certificate
active
06510698
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of replacing and operating a refrigeration system or an air conditioning system employing the refrigeration system. Further, the present invention relates to a method of replacing a refrigerant in a refrigeration system.
More particularly, the present invention relates to a refrigeration system which employs a refrigeration cycle (hereinafter referred to as a “refrigeration system”) and enables replacement of a heat source unit with a new one or replacement of a heat source unit and an indoor unit with new ones and which enables replacement of a previous-employed refrigerant with a new refrigerant of different type without involvement of replacement of at least connecting pipes for connecting the heat source unit with the indoor unit. The present invention further relates to a method of operating such refrigeration system.
2. Background Art
FIG. 27
shows a popular standalone-type refrigeration system which has already been used. In
FIG. 27
, reference symbol AA designates a heat source unit accommodating a compressor
1
, a four-way valve
2
, a heat exchanger
3
at a heat-source-unit side, a first control valve
4
, a second control valve
7
, and an accumulator
8
. Reference symbol BB designates an indoor unit including a flow rate regulator
5
(or a flow rate control valve
5
) and a heat exchanger
6
at a user-side. The heat source unit AA and the indoor unit BB are remotely separated from each other and are interconnected together by way of a first connecting pipe CC and a second connecting pipe DD, thus constituting a refrigeration system (i.e., a system employing the refrigeration cycle).
One end of the first connecting pipe CC is connected to the heat exchanger
3
on the heat-source-unit-side by way of the first control valve
4
, and the other end of the first connecting pipe CC is connected to the flow rate regulator
5
. One end of the second connecting pipe DD is connected to the four-way valve
2
by way of the second control valve
7
, and the other end of the second connecting pipe DD is connected to the heat exchanger
6
on the user-side. Further, an oil return hole
8
a
is formed in a lower portion of a U-shaped outlet pipe of the accumulator
8
.
The circulation of a refrigerant within the refrigeration system will now be described by reference to FIG.
27
. In the drawing, solid arrows depict the circulation of the refrigerant during a cooling operation, and dotted arrows depict the circulation of the refrigerant during a heating operation.
First will be explained the circulation of a refrigerant during a cooling operation. The refrigerant is compressed by the compressor
1
to assume the form of a hot, high-pressure gas; flows via the four-way valve
2
into the heat-source-unit-side heat exchanger
3
, where the gaseous refrigerant exchanges heat with a heat source medium, such as water or air; and is condensed. The thus-condensed refrigerant flows, via the first control valve
4
and the first connecting pipe CC, to the flow rate regulator
5
, where the refrigerant is decompressed to a low-pressure two-phase state. By way of the user-side heat exchanger
6
, the refrigerant exchanges heat with a user-side medium, such as air, and evaporates. The thus-evaporated refrigerant returns to the compressor
1
via the second connecting pipe DD, the second control valve
7
, the four-way valve
2
, and the accumulator B.
Next will be explained the circulation of the refrigerant during a heating operation. The refrigerant is compressed by the compressor
1
to assume the form of a hot, high-pressure gas; and flows via the four-way valve
2
, the second control valve
7
, and the second connecting pipe DD into the user-side heat exchanger
6
, where the gaseous refrigerant exchanges heat with a heat source medium, such as air, and is condensed. The thus-condensed refrigerant flows to the flow rate regulator
5
, where the refrigerant is decompressed to assume a low-pressure two-phase state. By way of the first connecting pipe CC, the first control valve
4
, and the heat-source-unit-side heat exchanger
3
, the refrigerant exchanges heat with a heat-source-unit-side medium, such as air or water, and is vaporized. The thus-vaporized refrigerant returns to the compressor
1
via the four-way valve
2
and the accumulator
8
.
Chlorofluorocarbon (CFC) or a hydrochlorofluorocarbon (HCFC) has been used as a refrigerant of such a refrigeration system. However, since chlorine contained in molecules of a CFC or HCFC depletes the ozone layer of the stratosphere, use of CFC has been phased out. Moreover, production of HCFCs has been subjected to regulation.
A refrigeration system using a hydrofluorocarbon (HFC) whose molecules do not contain chlorine has already been put into actual use. In a case where a refrigeration system using a CFC or HCFC (hereinafter referred to also as a “CFC/HCFC-using refrigeration system) is deteriorated and becomes unusable, the refrigeration system must be replaced with a new refrigeration system using an HFC (hereinafter referred to also as an “HFC-using refrigeration system), because use of CFCs has been phased out and production of HCFCs is regulated.
The heat source unit AA and the indoor unit BB for use with an HFC employ refrigeration oil, an organic material, and a heat exchanger which differ in type from those employed by the heat source unit AA and the indoor unit BB for use with an HCFC. Therefore, the refrigeration oil, the organic material, and the heat exchanger must be replaced with those designed specifically for use with an HFC. Further, let us assume that the heat source unit AA and the indoor unit BB for use with a CFC or HCFC have deteriorated and hence must be replaced with new ones. The heat source unit AA and the indoor unit BB can be replaced with new ones with comparative ease.
In a case where the first connecting pipe CC and the second connecting pipe DD interconnecting the heat source unit AA and the indoor unit BB are lengthy and embedded in a structure, such as a pipe shaft or a ceiling, difficulty is encountered in replacing the connecting pipes with new pipes. Further, these connecting pipes are not susceptible to deterioration, and hence if the first connecting pipe CC and the second connecting pipe DD used in the CFC/HCFC-using refrigeration system are usable, in their present forms, piping work can be facilitated.
In the first connecting pipe CC and the second connecting pipe DD used in the CFC/HCFC-using refrigeration system, there still remains residual mineral oil which has been used as a refrigeration oil for the CFC/HCFC-using refrigeration system (hereinafter called a “CFC/HCFC refrigeration oil), CFC/HCFC, or depleted substances).
FIG. 28
is a graph showing critical solubility curves which represent the solubility of an oil for use with an HFC (hereinafter called simply as an “HFC refrigeration oil”) in an HFC refrigerant when the HFC refrigeration oil is mixed with a mineral oil. The horizontal axis of the graph represents amount of oil (wt. %), and the vertical axis of the graph represents temperature (° C.).
As shown in
FIG. 28
, if a predetermined amount of mineral oil is mixed into an oil for use with a refrigeration system using an HFC (hereinafter also called an “HFC refrigeration oil”) (e.g., a synthetic fluid such as an ester oil or an ether oil), the refrigeration oil loses compatibility with an HFC refrigerant. If a puddle of liquid refrigerant is present in the accumulator
8
, the HFC refrigeration oil is isolated from and suspended in the liquid refrigerant. Accordingly, the HFC refrigeration oil does not return to the compressor
1
by way of the oil return hole
8
a
formed in the lower portion of the accumulator
8
, thus causing a sliding section of the compressor
1
to seize up.
If a mineral oil is mixed into the HFC refrigeration oil, the HFC refrigeration oil becomes deteriorated. Alternatively, if a CFC or HCFC is mixed into the HFC refrigeration oil, a chlorine component cont
Ikeda Takashi
Kasai Tomohiko
Kikukawa Toshihiro
Koge Hirofumi
Kurachi Mitsunori
Jiang Chen-Wen
Mitsubishi Denki & Kabushiki Kaisha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
LandOfFree
Refrigeration system, and method of updating and operating... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Refrigeration system, and method of updating and operating..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Refrigeration system, and method of updating and operating... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3053941