Refrigeration – Reversible – i.e. – heat pump
Reexamination Certificate
1999-01-28
2001-05-01
Doerrler, William (Department: 3744)
Refrigeration
Reversible, i.e., heat pump
C062S324600, C062S470000
Reexamination Certificate
active
06223549
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to exchange of the refrigerant in a refrigeration cycle device, in particular, a refrigeration cycle device in which a refrigerant is newly exchanged while newly exchanging only a heat source equipment and an indoor unit without exchanging connection pipes for connecting the heat source equipment to the indoor unit, a method of exchanging the device, and a method of operating the device.
2. Discussion of Background
In
FIG. 11
, an air conditioner of a separate-type which is generally and conventionally used is shown. In
FIG. 11
, reference A designates a heat source equipment; numerical reference
1
designates a compressor; numerical reference
2
designates a four-way valve; numerical reference
3
designates a heat exchanger on a heat source equipment side; numerical reference
4
designates a first control valve; numerical reference
7
designates a second control valve; and numerical reference
8
designates an accumulator, wherein the numerical references
1
through
8
are built in the heat source equipment A. Reference B designates an indoor unit, which includes a flow rate adjuster
5
(or a flow control valve
5
) and a heat exchanger
6
on an application side. The heat source equipment A and the indoor unit B are separately located and connected through a first connection pipe C and a second connection pipe D, whereby a refrigeration cycle is formed.
One end of the first connection pipe C is connected to the heat exchanger
3
on the heat source equipment side through the first control valve
4
and the other end of the first connection pipe C is connected to the flow rate adjuster
5
. One end of the second connection pipe D is connected to the four-way valve
2
through the second control valve
7
and the other end of the second connection pipe D is connected to the heat exchanger
6
on the application side. Further, an oil return hole
8
a
is provided in a lower portion of an effluent pipe having a U-like shape of the accumulator
8
.
A refrigerant flow of the air conditioner will be described in reference of FIG.
11
. In
FIG. 11
, an arrow of solid line designates a flow in cooling operation and an arrow of broken line designates a flow in heating operation.
At first, the flow in cooling operation will be described. A gas refrigerant having a high-temperature and a high-pressure, which is compressed by the compressor
1
flows through the four-way valve
2
to the heat exchanger on the heat source equipment side
3
, wherein it is condensed and liquefied by exchanging heat with a heat source medium such as air and water. Thus condensed and liquefied refrigerant flows through the first control valve
4
and the first connection pipe C to a flow rate adjuster
5
, wherein it is depressurized to a low pressure to be in a two-phase state of a low pressure and evaporates and vaporized by exchanging heat with a medium on the application side such as air in the heat exchanger on the application side
6
. Thus evaporated and vaporized refrigerant returns to the compressor
1
through the second connection pipe D, the second control valve
7
, the four-way valve
2
, and the accumulator
8
.
In the next, a flow in heating operation will be described. A gas refrigerant in a high-temperature and a high-pressure which is compressed by the compressor
1
flows into the heat exchanger on the application side
6
through the four-way valve
2
, the second control valve
7
and the second connection pipe D and is condensed and liquefied by exchanging heat with a medium on the application side such as air in the heat exchanger
6
. Thus condensed and liquefied refrigerant flows into the flow rate adjuster
5
, wherein it is depressurized to a low pressure to be a two phase state of a low pressure and evaporates and vaporizes by exchanging heat with a heat source medium such as air and water in the heat exchanger on the heat source equipment side
3
after passing through the first connection pipe C and the first control valve
4
. Thus evaporating and vaporizing refrigerant returns to the compressor
1
through the four-way valve
2
and the accumulator
8
.
Conventionally, chloro fluoro carbon (hereinbelow referred to as CFC) or hydro chloro fluoro carbon (hereinbelow referred to as HCFC) is used as a refrigerant for such an air conditioner. However, chlorine contained in the these molecules destructs an ozone layer in the stratosphere. Therefore, CFC was already abolished and production of HCFC was already started to regulate.
Instead of these, hydro fluoro carbon (hereinbelow referred to as HFC) which does not contain chlorine in its molecules is practically used for an air conditioner. When an air conditioner using CFC or HCFC is aged, it is necessary to substitute an air conditioner using HFC because the refrigerant such as CFC and HCFC has been abolished or regulated to produce.
Because the heat source equipment A and the indoor unit B use a refrigerating machine oil, an organic material, and an heat exchanger respectively for HFC are different from those for HCFC, it is necessary to change a refrigerating machine oil, an organic material, and a heat exchanger, respectively for exclusive use of HFC. Further, because the heat source equipment A and the indoor unit B respectively for CFC or HCFC may be aged, it is necessary to exchange these and such an exchange is relatively easy.
On the other hand, because in a case that the first connection pipe C and the second connection pipe D connecting the heat source equipment A to the indoor unit B are long or are buried in a pipe shaft, above a ceiling, in a like location of a building, it is difficult to exchange for new pipes and existing pipes are ordinarily not decrepit, it is possible to simplify piping work by using the existing first connection pipe C and the existing second connection pipe D for the air conditioner using CFC or HCFC.
However, in the first connection pipe C and the second connection pipe D used for the air conditioner utilizing CFC or HCFC, a refrigerating machine oil of a mineral oil for the air conditioner utilizing CFC or HCFC and a deteriorated substance of a refrigerating machine oil retain as a sludge.
FIG. 12
shows a critical solubility curve for a exhibiting solubility of a refrigerating machine oil for HFC with a refrigerant of HFC (R407C) when a mineral oil is mixed to the refrigerant, wherein an abscissa designates a quantity of oil (WT %) and an ordinate designates a temperature (° C.). When a certain quantity or more of a mineral oil is included in a refrigerating machine oil (a synthetic oil such as an ester oil or an ether oil) of an air conditioner utilizing HFC, compatibility with a HFC refrigerant is lost as shown in
FIG. 12
, wherein in a case that a liquid refrigerant is accumulated in a accumulator
8
, the refrigerating machine oil for HFC separates and flows on the liquid refrigerant, whereby a sliding portion of compressor is seized because the refrigerating machine oil does not return from an oil return hole
8
a
located in a lower portion of the accumulator
8
to the compressor.
Further, when a mineral oil is mixed, the refrigerating machine oil for HFC is deteriorated. Further, when CFC or HCFC is mixed in the refrigerating machine oil for HFC, it is deteriorated by a component of chlorine contained in CFC or HCFC. Further, the refrigerating machine oil for HFC is deteriorated by a component of chlorine contained in sludge of a deteriorated substance of refrigerating machine oil for CFC or HCFC.
Therefore, a first connection pipe C and a second connection pipe D, which were used in an air conditioner utilizing CFC or HCFC, were conventionally cleaned by a flushing liquid for exclusive use, (ex. HCFC 141b or HCFC 225) in use of a flushing machine. Hereinbelow, such a method is referred to as a flushing method
1
.
In the next, another method is disclosed in JP-A-7-83545. There is proposed, as shown in
FIG. 13
, a heat source equipment A for HFC, an indoor unit B for HFC, a first conne
Doerrler William
Jiang Chen-Wen
Mitsubishi Denki & Kabushiki Kaisha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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