U.S. patent application number 11/342882 was filed with the patent office on 2006-08-03 for refrigerating device, refrigerator, compressor, and gas-liguid separator.
This patent application is currently assigned to SANYO ELECTRIC CO., LTD.. Invention is credited to Satoshi Imai, Hiroyuki Itsuki, Hiroshi Mukaiyama, Etsushi Nagae, Itsuo Nakazaki, Masahisa Otake, Akira Sugawara.
Application Number | 20060168996 11/342882 |
Document ID | / |
Family ID | 36499394 |
Filed Date | 2006-08-03 |
United States Patent
Application |
20060168996 |
Kind Code |
A1 |
Imai; Satoshi ; et
al. |
August 3, 2006 |
Refrigerating device, refrigerator, compressor, and gas-liguid
separator
Abstract
An object is to provide a refrigerating device capable of
realizing a high-efficiency operation in a case where there is
disposed, in a refrigerating cycle, a compressor having: a
plurality of heat sinks which function in different temperature
zones; and an intermediate-pressure portion. The refrigerating
device comprises: the compressor having the intermediate-pressure
portion; and a radiator connected to a discharge side of the
compressor, a refrigerant pipe on an outlet side of the radiator is
branched, one of the branched refrigerant pipes is provided with a
first heat absorbing unit including a first pressure reducing
section and a first heat sink, and the other refrigerant pipe is
provided with a second heat absorbing unit including a second
pressure reducing section and a second heat sink. The one
refrigerant pipe is connected to the intermediate-pressure portion
of the compressor, and the other refrigerant pipe is connected to a
suction portion of the compressor on a low-pressure side of the
intermediate-pressure portion.
Inventors: |
Imai; Satoshi; (Gunma,
JP) ; Itsuki; Hiroyuki; (Gunma, JP) ;
Mukaiyama; Hiroshi; (Gunma, JP) ; Otake;
Masahisa; (Gunma, JP) ; Nagae; Etsushi;
(Gunma, JP) ; Nakazaki; Itsuo; (Gunma, JP)
; Sugawara; Akira; (Saitama, JP) |
Correspondence
Address: |
MCDERMOTT WILL & EMERY LLP
600 13TH STREET, N.W.
WASHINGTON
DC
20005-3096
US
|
Assignee: |
SANYO ELECTRIC CO., LTD.
|
Family ID: |
36499394 |
Appl. No.: |
11/342882 |
Filed: |
January 31, 2006 |
Current U.S.
Class: |
62/510 ;
62/513 |
Current CPC
Class: |
F04C 29/005 20130101;
F25D 2317/0682 20130101; F01C 21/0818 20130101; F25B 31/026
20130101; F25B 1/10 20130101; F25B 2400/23 20130101; F25D 17/065
20130101; F25B 2309/061 20130101; F25B 2400/13 20130101; F04C
2270/20 20130101; F25B 5/02 20130101; F25D 11/022 20130101; F25B
9/008 20130101; F04C 23/001 20130101; F25B 2400/072 20130101; F04C
18/3564 20130101; F25B 1/04 20130101; F04C 23/008 20130101 |
Class at
Publication: |
062/510 ;
062/513 |
International
Class: |
F25B 1/10 20060101
F25B001/10; F25B 41/00 20060101 F25B041/00 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 31, 2005 |
JP |
2005-24211 |
Feb 28, 2005 |
JP |
2005-54708 |
Mar 30, 2005 |
JP |
2005-100182 |
Mar 30, 2005 |
JP |
2005-100183 |
Mar 30, 2005 |
JP |
2005-100185 |
Claims
1. A refrigerating device comprising: a compressor having an
intermediate-pressure portion; and a radiator connected to a
discharge side of the compressor, the radiator including a
refrigerant pipe which is branched on an outlet side of the
radiator, one of the branched refrigerant pipes being provided with
first heat absorbing means including first pressure reducing means
and a first heat sink, the other branched refrigerant pipe being
provided with second heat absorbing means including second pressure
reducing means and a second heat sink, wherein the one refrigerant
pipe is connected to the intermediate-pressure portion of the
compressor, and the other refrigerant pipe is connected to a
suction portion of the compressor on a low-pressure side of the
intermediate-pressure portion.
2. The refrigerating device according to claim 1, further
comprising: a heat exchanger via which heat is exchangeable between
a refrigerant discharged from the first heat sink and a refrigerant
which is discharged from the radiator and which is to be
branched.
3. The refrigerating device according to claim 1 or 2, wherein the
first heat absorbing means and the second heat absorbing means
function in different temperature zones.
4. The refrigerating device according to claim 3, wherein the
second heat absorbing means functions in a temperature zone which
is lower than that of the first heat absorbing means.
5. A refrigerator comprising: the refrigerating device according to
claims 1 to 4.
6. The refrigerator according to claim 5 further comprising: a
refrigerating room; and a freezing room operated at a temperature
which is lower than that of the refrigerating room, the
refrigerating room being cooled by the first heat absorbing means,
the freezing room being cooled by the second heat absorbing
means.
7. The refrigerating device according to claims 1 to 4, and the
refrigerator according to claim 5 or 6, wherein carbon dioxide is
used as a refrigerant.
8. A compressor comprising: an electromotive element; and a
compression chamber which is driven by the electromotive element to
compress a fluid, the electromotive element and the compression
chamber being disposed in a sealed container, wherein the
compression chamber includes: an introducing port for introducing
the fluid into the compression chamber; and first and second
discharge ports for discharging the compressed fluid, the first
discharge port is provided with a first discharge valve which is
opened in a case where the fluid compressed in the compression
chamber reaches a first pressure, and the second discharge port is
provided with a second discharge valve which is opened at a second
pressure which is higher than the first pressure.
9. The compressor according to claim 8, wherein the fluid is an
oil-containing refrigerant.
10. The compressor according to any one of claims 8 and 9, wherein
the compression element is constituted of: a front-stage
compression element; and a rear-stage compression element which
further compresses the refrigerant compressed by the front-stage
compression element, the compression chamber of the front-stage
compression element is provided with the introducing port, the
first discharge port, the first discharge valve, the second
discharge port, and the second discharge valve, and the second
discharge valve is opened at a pressure which is higher than that
of the refrigerant discharged from the rear-stage compression
element.
11. The compressor according to claim 10, wherein the second
discharge valve is brought into contact with the refrigerant in the
compression chamber and the refrigerant discharged from the
rear-stage compression element.
12. A refrigerating device comprising: the compressor according to
claim 8; a radiator connected to a discharge side of the
compressor; first heat absorbing means connected to one of branched
refrigerant pipes on an outlet side of the radiator and including
first pressure reducing means and a first heat sink; and second
heat absorbing means connected to the other branched refrigerant
pipe and including second pressure reducing means and a second heat
sink, the one refrigerant pipe being connected to an
intermediate-pressure portion of the compressor, the other
refrigerant pipe being connected to a suction port of the
compressor on a low-pressure side of the intermediate-pressure
portion.
13. The refrigerating device according to claim 12, wherein a
high-pressure side of a refrigerating cycle is operated in a
supercritical state.
14. A refrigerator comprising: the refrigerating device according
to any one of claims 12 and 13.
15. A refrigerating device comprising: compression means including
a front-stage compression element and a rear-stage compression
element; a radiator connected to a discharge side of the
compression means; first heat absorbing means connected to one of
branched refrigerant pipes on an outlet side of the radiator and
including first pressure reducing means and a first heat sink;
second heat absorbing means connected to the other branched
refrigerant pipe and including second pressure reducing means and a
second heat sink; changeover means for selecting circulation of a
refrigerant to the first heat absorbing means and the second heat
absorbing means; and control means for controlling a compressing
operation of the compression means based on information of the
changeover means, the refrigerant pipe on the outlet side of the
first heat absorbing means being connected between the discharge
side of the front-stage compression element and a suction port of
the rear-stage compression element, the refrigerant pipe on the
outlet side of the second heat absorbing means being connected to a
suction port of the front-stage compression element, the control
means stopping the compressing operation of the front-stage
compression element in a case where the refrigerant is circulated
in the first heat absorbing means and the circulation of the
refrigerant to the second heat absorbing means is interrupted.
16. The refrigerating device according to claim 15, wherein the
compression means is constituted of two compressors, one of the two
compressors is operated as the front-stage compression element, the
other compressor is operated as the rear-stage compression element,
and the control means stops the operation of the one compressor in
a case where the refrigerant is circulated in the first heat
absorbing means and the circulation of the refrigerant to the
second heat absorbing means is interrupted.
17. The refrigerating device according to claim 15, wherein the
compression means contains the front-stage compression element and
the rear-stage compression element in one sealed container, each of
the compression elements is constituted of a rotary multistage
compressor including a vane and a roller and operating via the same
rotation shaft, the multistage compressor includes contact
prevention means for preventing the vane of the front-stage
compression element from being brought into contact with the
roller, and the control means operates the contact prevention means
to prevent the vane of the front-stage compression element from
being brought into contact with the roller in a case where the
refrigerant is circulated in the first heat absorbing means and the
circulation of the refrigerant to the second heat absorbing means
is interrupted.
18. The refrigerating device according to claim 15, wherein the
compression means contains the front-stage compression element and
the rear-stage compression element in one sealed container, the
front-stage compression element operates via a first rotation
shaft, the rear-stage compression element operates via a second
rotation shaft, the first rotation shaft is attached to driving
means, the first rotation shaft is connected to the second rotation
shaft via a clutch mechanism, and the control means disconnects the
second rotation shaft from the first rotation shaft via the clutch
mechanism in a case where the refrigerant is circulated in the
first heat absorbing means and the circulation of the refrigerant
to the second heat absorbing means is interrupted.
19. The refrigerating device according to any one of claims 15 to
18, wherein carbon dioxide is used as the refrigerant.
20. The refrigerating device according to any one of claims 15 to
19, wherein a high-pressure side of a refrigerating cycle is
operated in a supercritical state.
21. A refrigerator comprising: the refrigerating device according
to any one of claims 15 to 20.
22. A compressor comprising: a vane; a roller; and contact
prevention means for preventing the vane from being brought into
contact with the roller.
23. The compressor according to claim 22, wherein the contact
prevention means includes: a magnet attached to the vane; and an
electromagnet capable of generating a magnetic force which reacts
against the magnet or which attracts the magnet.
24. The compressor according to claim 23, wherein the magnetic
force is generated so that the electromagnet reacts against the
magnet in a case where a refrigerant compressing operation is
performed, and the magnetic force is generated so that the
electromagnet attracts the magnet in a case where the refrigerant
compressing operation is stopped.
25. A compressor containing a front-stage compression element and a
rear-stage compression element in one sealed container, the
front-stage compression element operating via a first rotation
shaft, the rear-stage compression element operating via a second
rotation shaft, the first rotation shaft being attached to driving
means, the first rotation shaft being connected to the second
rotation shaft via a clutch mechanism.
26. The compressor according to claim 25, wherein the clutch
mechanism disconnects the second rotation shaft from the first
rotation shaft in a case where a compressing operation of the
front-stage compression element is stopped, and a compressing
operation of the rear-stage compression element is performed.
27. A refrigerating device comprising a refrigerating cycle
including: a compressor; a radiator connected to a discharge side
of the compressor; first pressure reducing means connected to an
outlet side of the radiator; second pressure reducing means
disposed in series to the first pressure reducing means; and a heat
sink connected to an outlet side of the second pressure reducing
means, wherein adsorbing means for adsorbing a water content from a
refrigerant is disposed between the outlet side of the first
pressure reducing means and an inlet side of the second pressure
reducing means.
28. A gas-liquid separator comprising: a container into which a
mixed refrigerant of a gas and a liquid is introduced and in which
the refrigerant is separated into the gas and the liquid; an
introducing tube for introducing the refrigerant into the
container; a first outlet tube out of which the gas refrigerant
separated in the container flows; and a second outlet tube out of
which the liquid refrigerant separated in the container flows, the
container being provided with an adsorbing section for adsorbing a
water content from the refrigerant.
29. A refrigerating device comprising a refrigerating cycle
including: a compressor; a radiator connected to a discharge side
of the compressor; first pressure reducing means connected to an
outlet side of the radiator; second pressure reducing means
disposed in series to the first pressure reducing means; and a heat
sink connected to an outlet side of the second pressure reducing
means, wherein the gas-liquid separator according to claim 28 is
disposed between an outlet side of the first pressure reducing
means and an inlet side of the second pressure reducing means.
30. The refrigerating device according to claim 29, wherein the
compressor has an intermediate-pressure portion, and the first
outlet tube of the gas-liquid separator is connected to the
intermediate-pressure portion.
31. The refrigerating device according to any one of claims 27, 29,
and 30, wherein a high-pressure part of the refrigerating cycle is
operated at a supercritical pressure.
32. The refrigerating device according to any one of claims 27, 29,
30, and 31, wherein carbon dioxide is used as the refrigerant.
33. A refrigerator comprising: the refrigerating device according
to any one of claims 27, 29, 30, 31, and 32.
Description
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a refrigerating device
provided with a plurality of heat sinks having different
evaporation temperatures, and a refrigerator provided with this
refrigerating device.
[0002] Moreover, the present invention relates to a refrigerating
device provided with compression means for compressing a
refrigerant in multiple stages, and a refrigerator, further to a
compressor which is applicable to such refrigerating device.
[0003] Furthermore, the present invention relates to a
refrigerating device provided with means for adsorbing a water
content from a refrigerant, a refrigerator, and a gas-liquid
separator which is disposed in a refrigerating cycle and which
performs gas-liquid separation of a gas-liquid mixed
refrigerant.
[0004] In general, a refrigerating device is known which includes a
plurality of heat sinks and in which these heat sinks are operated
in different temperature zones to thereby achieve a high-efficiency
operation with respect to a plurality of cooling loads at different
temperatures.
[0005] As one example of such refrigerating device, in Japanese
Patent Application Laid-Open No. 2000-230767, a refrigerator is
disclosed in which a compressor and a condenser are combined and in
which two heat sinks are connected in parallel to each other and
which switches these heat sinks to cool a freezing room and a
refrigerating room independently of each other.
[0006] Additionally, in this type of refrigerating device, there is
sometimes applied a compressor having an intermediate-pressure
portion, for example, a compressor having a multistage compression
mechanism.
[0007] In a case where the compressor having such
intermediate-pressure portion is applied to the refrigerating
device or the refrigerator as described above, when the
refrigerating cycle suitable for use in the intermediate-pressure
portion is constructed, it is sometimes possible to realize the
refrigerating device which can be operated with a high
efficiency.
[0008] Moreover, in recent years, it has been demanded that energy
be largely saved in a freezer/refrigerator provided with the
refrigerating room and the freezing room. For example, in Japanese
Patent Application Laid-Open No. 11-223397, in order to realize
such energy saving, there is proposed a freezer/refrigerator
provided with a two-stage compression refrigerating cycle
constituted of: a compressor including a front-stage compression
element and a rear-stage compression element; a condenser; first
expansion means; an evaporator for the refrigerating room; second
expansion means; and an evaporator for the freezing room.
[0009] However, the above-described constitution has a problem that
one of the freezing room and the refrigerating room is brought into
shortage or excess of a refrigerating capability in a case where
the cooling loads of the rooms are unbalanced.
[0010] To solve such problem, in Japanese Patent Application
Laid-Open No. 2001-108345, there is proposed a two-stage
compression freezing and refrigerating storage including: a
two-stage compressor; an expansion device for an intermediate
pressure; a heat sink for the intermediate pressure; an expansion
device for a low pressure; a heat sink for the low pressure and the
like. Between front-stage and rear-stage sides of the two-stage
compressor, there is connected a refrigerant pipe which connects
the expansion device for the intermediate pressure to the heat sink
for the intermediate pressure.
[0011] In addition, in the two-stage compression freezing and
refrigerating storage constituted as described above, during a
refrigerating operation to stop a cooling function in the heat sink
for the low pressure and allow the heat sink for the intermediate
pressure to function, a front-stage compression chamber of the
two-stage compressor is substantially brought into a vacuum state.
Therefore, a large amount of oil flows into the compression chamber
to cause liquid compression, and a compressor efficiency sometimes
largely drops.
[0012] Moreover, in general, in the refrigerating device having the
refrigerating cycle provided with the compressor and the like, the
inside of the pipe is sometimes frozen by the water content mixed
in the refrigerating cycle, and accordingly reliability of the
refrigerating cycle sometimes degrades. As to means for preventing
the above-described freezing in such refrigerating device, it is
known that a drier as water content removing means is disposed in
the refrigerating cycle.
[0013] In Japanese Patent Application Laid-Open No. 11-21548, it is
described that there is disposed the drier filled with zeolite or
the like for removing the water content mixed in a refrigerant
between an condenser outlet side and an expansion valve inlet side
which are high-pressure sides of the refrigerating cycle in the
refrigerating device provided with the compressor, the condenser,
the expansion valve, the evaporator and the like.
[0014] In addition, in this type of refrigerating device, there is
a case where carbon dioxide or the like is used as the refrigerant.
In this case, for example, the high-pressure side is sometimes
operated under a supercritical pressure. In the refrigerating
device in which such carbon dioxide refrigerant is used, the
high-pressure side of the refrigerating cycle has higher
temperature and pressure as compared with a refrigerating device in
which hydrofluorocarbon (HFC) or the like is used as the
refrigerant. Therefore, in a case where the drier is disposed on
the high-pressure side of the refrigerating cycle as described
above, there is a possibility that a drying agent charged in the
drier is crushed.
SUMMARY OF THE INVENTION
[0015] An object of the present invention is to provide a
refrigerating device capable of realizing a higher-efficiency
operation in any temperature zone and a refrigerator provided with
this refrigerating device in a case where there is disposed, in a
refrigerating cycle, a compressor having: a plurality of heat sinks
functioning in different temperature zones; and an
intermediate-pressure portion.
[0016] In a first aspect of the present invention, a refrigerating
device comprises: a compressor having an intermediate-pressure
portion; and a radiator connected to a discharge side of the
compressor, a refrigerant pipe on an outlet side of the radiator
being branched, one of the branched refrigerant pipes being
provided with first heat absorbing means including first pressure
reducing means and a first heat sink, the other branched
refrigerant pipe being provided with second heat absorbing means
including second pressure reducing means and a second heat sink,
wherein the one refrigerant pipe is connected to the
intermediate-pressure portion of the compressor, and the other
refrigerant pipe is connected to a suction portion of the
compressor on a low-pressure side of the intermediate-pressure
portion.
[0017] In a second aspect of the present invention, the
refrigerating device of the first aspect of the present invention,
further comprises: a heat exchanger via which heat is exchangeable
between a refrigerant discharged from the first heat sink and a
refrigerant which is discharged from the radiator and which is to
be branched.
[0018] In a third aspect of the present invention, in the
refrigerating device of the first or second aspect of the present
invention, the first heat absorbing means and the second heat
absorbing means function in different temperature zones.
[0019] In a fourth aspect of the present invention, in the
refrigerating device of the third aspect of the present invention,
the second heat absorbing means functions in a temperature zone
which is lower than that of the first heat absorbing means.
[0020] In a fifth aspect of the present invention, a refrigerator
comprises: the refrigerating device of the first to fourth aspects
of the present invention.
[0021] In a sixth aspect of the present invention, the refrigerator
of the fifth aspect of the present invention further comprises: a
refrigerating room; and a freezing room operated at a temperature
which is lower than that of the refrigerating room, the
refrigerating room is cooled by the first heat absorbing means, and
the freezing room is cooled by the second heat absorbing means.
[0022] In a seventh aspect of the present invention, in the
refrigerating device of the first to fourth aspects of the present
invention, and the refrigerator of the fifth or sixth aspect of the
present invention, carbon dioxide is used as a refrigerant.
[0023] In the first to seventh aspects of the present invention,
there is disposed the heat absorbing means which functions in the
different temperature zones. Accordingly, there is provided the
refrigerating device capable of operating with a high efficiency,
and the refrigerator capable of operating with the high
efficiency.
[0024] Moreover, an object of the present invention is to provide:
a refrigerating device and a refrigerator which are provided with a
plurality of heat sinks operating in different temperature zones
and which are capable of inhibiting degradation of a compressor
efficiency even in a case where a refrigerant pipe extended from
one heat sink is connected to an intermediate-pressure portion of a
compressor; and the compressor which is applicable to these
devices.
[0025] In an eighth aspect of the present invention, in a
compressor comprising: an electromotive element; and a compression
chamber which is driven by the electromotive element to compress a
fluid, the electromotive element and the compression chamber being
disposed in a sealed container, the compression chamber includes:
an introducing port for introducing the fluid into the compression
chamber; and first and second discharge ports for discharging the
compressed fluid, the first discharge port is provided with a first
discharge valve which is opened in a case where the fluid
compressed in the compression chamber reaches a first pressure, and
the second discharge port is provided with a second discharge valve
which is opened at a second pressure which is higher than the first
pressure.
[0026] In a ninth aspect of the present invention, in the
compressor of the eighth aspect of the present invention, the fluid
is an oil-containing refrigerant.
[0027] In a tenth aspect of the present invention, in the
compressor of any one of the eighth and ninth aspects of the
present invention, the compression element is constituted of: a
front-stage compression element; and a rear-stage compression
element which further compresses the refrigerant compressed by the
front-stage compression element. The compression chamber of the
front-stage compression element is provided with the introducing
port, the first discharge port, the first discharge valve, the
second discharge port, and the second discharge valve, and the
second discharge valve is opened at a pressure which is higher than
that of the refrigerant discharged from the rear-stage compression
element.
[0028] In an eleventh aspect of the present invention, in the
compressor of the tenth aspect of the present invention, the second
discharge valve is brought into contact with the refrigerant in the
compression chamber and the refrigerant discharged from the
rear-stage compression element.
[0029] In a twelfth aspect of the present invention, a
refrigerating device comprises: the compressor of the eighth aspect
of the present invention; a radiator connected to a discharge side
of the compressor; first heat absorbing means connected to one of
branched refrigerant pipes on an outlet side of the radiator and
including first pressure reducing means and a first heat sink; and
second heat absorbing means connected to the other branched
refrigerant pipe and including second pressure reducing means and a
second heat sink, the one refrigerant pipe being connected to an
intermediate-pressure portion of the compressor, the other
refrigerant pipe being connected to a suction port of the
compressor on a low-pressure side of the intermediate-pressure
portion.
[0030] In a 13th aspect of the present invention, in the
refrigerating device of the twelfth aspect of the present
invention, a high-pressure side of a refrigerating cycle is
operated in a supercritical state.
[0031] In a 14th aspect of the present invention, a refrigerator
comprises: the refrigerating device of any one of the twelfth and
13th aspects of the present invention.
[0032] According to the eighth to fourteenth aspects of the present
invention, there are provided: the refrigerating device and the
refrigerator which are provided with the plurality of heat sinks
operating in the different temperature zones and which are capable
of inhibiting the degradation of the compressor efficiency even in
the case where the refrigerant pipe extended from one heat sink is
connected to the intermediate-pressure portion of the compressor;
and the compressor which is applicable to these devices.
[0033] In a 15th aspect of the present invention, a refrigerating
device comprises: compression means including a front-stage
compression element and a rear-stage compression element; a
radiator connected to a discharge side of the compression means;
first heat absorbing means connected to one of branched refrigerant
pipes on an outlet side of the radiator and including first
pressure reducing means and a first heat sink; and second heat
absorbing means connected to the other branched refrigerant pipe
and including second pressure reducing means and a second heat
sink; changeover means for selecting circulation of a refrigerant
to the first heat absorbing means and the second heat absorbing
means; and control means for controlling a compressing operation of
the compression means based on information of the changeover means.
The refrigerant pipe on the outlet side of the first heat absorbing
means is connected between the discharge side of the front-stage
compression element and a suction port of the rear-stage
compression element. The refrigerant pipe on the outlet side of the
second heat absorbing means is connected to a suction port of the
front-stage compression element. The control means stops the
compressing operation of the front-stage compression element in a
case where the refrigerant is circulated in the first heat
absorbing means and the circulation of the refrigerant to the
second heat absorbing means is interrupted.
[0034] In a 16th aspect of the present invention, in the
refrigerating device of the 15th aspect of the present invention,
the compression means is constituted of two compressors, one of the
two compressors is operated as the front-stage compression element,
the other compressor is operated as the rear-stage compression
element, and the control means stops the operation of the one
compressor in a case where the refrigerant is circulated in the
first heat absorbing means and the circulation of the refrigerant
to the second heat absorbing means is interrupted.
[0035] In a 17th aspect of the present invention, in the
refrigerating device of the 15th aspect, the compression means
contains the front-stage compression element and the rear-stage
compression element in one sealed container, each of the
compression elements is constituted of a rotary multistage
compressor including a vane and a roller and operating via the same
rotation shaft, the multistage compressor includes contact
prevention means for preventing the vane of the front-stage
compression element from being brought into contact with the
roller, and the control means operates the contact prevention means
to prevent the vane of the front-stage compression element from
being brought into contact with the roller in a case where the
refrigerant is circulated in the first heat absorbing means and the
circulation of the refrigerant to the second heat absorbing means
is interrupted.
[0036] In an 18th aspect of the present invention, in the
refrigerating device of the 15th aspect of the present invention,
the compression means contains the front-stage compression element
and the rear-stage compression element in one sealed container, the
front-stage compression element operates via a first rotation
shaft, the rear-stage compression element operates via a second
rotation shaft, the first rotation shaft is attached to driving
means, the first rotation shaft is connected to the second rotation
shaft via a clutch mechanism, and the control means disconnects the
second rotation shaft from the first rotation shaft via the clutch
mechanism in a case where the refrigerant is circulated in the
first heat absorbing means and the circulation of the refrigerant
to the second heat absorbing means is interrupted.
[0037] In a 19th aspect of the present invention, in the
refrigerating device of any one of 15th to 18th aspects of the
present invention, carbon dioxide is used as the refrigerant.
[0038] In a 20th aspect of the present invention, in the
refrigerating device of any one of the 15th to 19th aspects of the
present invention, a high-pressure side of a refrigerating cycle is
operated in a supercritical state.
[0039] In a 21st aspect of the present invention, a refrigerator
comprises: the refrigerating device of any one of the 15th to 20th
aspects of the present invention.
[0040] In a 22nd aspect of the present invention, a compressor
comprises: a vane; a roller; and contact prevention means for
preventing the vane from being brought into contact with the
roller.
[0041] In a 23rd aspect of the present invention, in the compressor
of the 22nd aspect of the present invention, the contact prevention
means includes: a magnet attached to the vane; and an electromagnet
capable of generating a magnetic force which reacts against the
magnet or which attracts the magnet.
[0042] In a 24th aspect of the present invention, in the compressor
of the 23rd aspect of the present invention, the magnetic force is
generated so that the electromagnet reacts against the magnet in a
case where a refrigerant compressing operation is performed, and
the magnetic force is generated so that the electromagnet attracts
the magnet in a case where the refrigerant compressing operation is
stopped.
[0043] In a 25th aspect of the present invention, a compressor
contains a front-stage compression element and a rear-stage
compression element in one sealed container, the front-stage
compression element operates via a first rotation shaft, the
rear-stage compression element operates via a second rotation
shaft, the first rotation shaft is attached to driving means, and
the first rotation shaft is connected to the second rotation shaft
via a clutch mechanism.
[0044] In a 26th aspect of the present invention, in the compressor
of the 25th aspect of the present invention, the clutch mechanism
disconnects the second rotation shaft from the first rotation shaft
in a case where a compressing operation of the front-stage
compression element is stopped, and a compressing operation of the
rear-stage compression element is performed.
[0045] According to the 15th to 26th aspects of the present
invention, there are provided: the refrigerating device and the
refrigerator which are provided with the plurality of heat sinks
operating in the different temperature zones and which are capable
of inhibiting the degradation of the compressor efficiency even in
the case where the refrigerant pipe extended from one heat sink is
connected to the intermediate-pressure portion of the compressor;
and the compressor which is applicable to these devices.
[0046] Furthermore, an object of the present invention is to
provide: a refrigerating device and a refrigerator which are
capable of inhibiting a drying agent from being crushed even in a
case where carbon dioxide or the like is used as a refrigerant; and
a gas-liquid separator disposed in a refrigerating cycle.
[0047] In a 27th aspect of the present invention, in a
refrigerating device comprising a refrigerating cycle including: a
compressor; a radiator connected to a discharge side of the
compressor; first pressure reducing means connected to an outlet
side of the radiator; second pressure reducing means disposed in
series to the first pressure reducing means; and a heat sink
connected to an outlet side of the second pressure reducing means,
adsorbing means for adsorbing a water content from a refrigerant is
disposed between the outlet side of the first pressure reducing
means and an inlet side of the second pressure reducing means.
[0048] In a 28th aspect of the present invention, a gas-liquid
separator comprises: a container into which a mixed refrigerant of
a gas and a liquid is introduced and in which the refrigerant is
separated into the gas and the liquid; an introducing tube for
introducing the refrigerant into the container; a first outlet tube
out of which the gas refrigerant separated in the container flows;
and a second outlet tube out of which the liquid refrigerant
separated in the container flows. The container is provided with an
adsorbing section for adsorbing a water content from the
refrigerant.
[0049] In a 29th aspect of the present invention, in a
refrigerating device comprising a refrigerating cycle including: a
compressor; a radiator connected to a discharge side of the
compressor; first pressure reducing means connected to an outlet
side of the radiator; second pressure reducing means disposed in
series to the first pressure reducing means; and a heat sink
connected to an outlet side of the second pressure reducing means,
the gas-liquid separator according to claim 28 is disposed between
an outlet side of the first pressure reducing means and an inlet
side of the second pressure reducing means.
[0050] In a 30th aspect of the present invention, in the
refrigerating device of the 29th aspect of the present invention,
the compressor has an intermediate-pressure portion, and the first
outlet tube of the gas-liquid separator is connected to the
intermediate-pressure portion.
[0051] In a 31st aspect of the present invention, in the
refrigerating device of any one of the 27th, 29th, and 30th aspects
of the present invention, a high-pressure part of the refrigerating
cycle is operated at a supercritical pressure.
[0052] In a 32nd aspect of the present invention, in the
refrigerating device of any one of the 27th, 29th, 30th, and 31st
aspects of the present invention, carbon dioxide is used as the
refrigerant.
[0053] In a 33rd aspect of the present invention, a refrigerator
comprises: the refrigerating device of any one of the 27th, 29th,
30th, 31st, and 32nd aspects of the present invention.
[0054] According to the 27th to 33rd aspects of the present
invention, there are provided: the refrigerating device and the
refrigerator which are capable of inhibiting the drying agent from
being crushed even in a case where carbon dioxide or the like is
used as the refrigerant; the refrigerating device and the
refrigerator whose performances can be improved even in a case
where there are a large amount of gas-phase components which do not
contribute to heat exchange in the heat sink; and the gas-liquid
separator disposed in the refrigerating cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
[0055] FIG. 1 is a refrigerant circuit diagram showing a
refrigerating device in Embodiment 1 of the present invention;
[0056] FIG. 2 is an enthalpy-pressure chart of a refrigerating
cycle in the refrigerating device of Embodiment 1 of the present
invention;
[0057] FIG. 3 is a schematic constitution diagram showing an
application example of the refrigerating device to a refrigerator
in Embodiment 1 of the present invention;
[0058] FIG. 4 is a refrigerant circuit diagram showing a
refrigerating device in Embodiment 2 of present invention;
[0059] FIG. 5 is a refrigerant circuit diagram showing a
refrigerating device in Embodiment 3 of the present invention;
[0060] FIG. 6 is a schematic sectional view of a compressor in
Embodiment 3 of the present invention;
[0061] FIG. 7 is a plan view including a cylinder of a first-stage
compressing section of the compressor in Embodiment 3 of the
present invention;
[0062] FIG. 8 is a schematic constitution diagram showing an
application example of the refrigerating device to a refrigerator
in Embodiment 3 of the present invention;
[0063] FIG. 9 is a refrigerant circuit diagram showing the
refrigerating device in Embodiment 4 of the present invention;
[0064] FIG. 10 is a schematic constitution diagram showing an
application example of the refrigerating device to a refrigerator
in Embodiment 4 of the present invention;
[0065] FIG. 11 is a refrigerant circuit diagram showing the
refrigerating device in Embodiment 5 of the present invention;
[0066] FIG. 12 is a schematic sectional view of a compressor in
Embodiment 5 of the present invention;
[0067] FIG. 13 is a schematic diagram showing a compression
mechanism of the compressor in Embodiment 5 of the present
invention;
[0068] FIG. 14 is a schematic diagram showing the compression
mechanism of the compressor in Embodiment 5 of the present
invention;
[0069] FIG. 15 is a refrigerant circuit diagram showing the
refrigerating device in Embodiment 6 of the present invention;
[0070] FIG. 16 is a schematic sectional view of a compressor in
Embodiment 6 of the present invention;
[0071] FIG. 17 is a schematic sectional view of the compressor in
Embodiment 6 of the present invention;
[0072] FIG. 11 is a refrigerant circuit diagram showing the
refrigerating device in Embodiment 5 of the present invention;
[0073] FIG. 18 is a refrigerator circuit diagram showing a
refrigerating device in Embodiment 7 of the present invention;
[0074] FIG. 19 is a schematic sectional view showing one example of
a gas-liquid separator of the present invention;
[0075] FIG. 20 is a schematic sectional view showing another
example of the gas-liquid separator of the present invention;
[0076] FIG. 21 is a schematic sectional view showing still another
example of the gas-liquid separator of the present invention;
[0077] FIG. 22 is a schematic constitution diagram showing an
application example of the refrigerating device to a refrigerator
in Embodiment 7 of the present invention;
[0078] FIG. 23 is a refrigerant circuit diagram showing a
refrigerating device in Embodiment 8 of the present invention;
[0079] FIG. 24 is a schematic constitution diagram showing an
application example of the refrigerating device to a refrigerator
in Embodiment 8 of the present invention;
[0080] FIG. 25 is a refrigerant circuit diagram showing a
refrigerating device in Embodiment 9 of the present invention;
[0081] FIG. 26 is a refrigerant circuit diagram showing a
refrigerating device in Embodiment 10 of the present invention;
and
[0082] FIG. 27 is a schematic sectional view showing a gas-liquid
separator applicable to the refrigerating device in Embodiment 10
of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0083] There will be described hereinafter preferred embodiments of
a refrigerating device and a refrigerator provided with the
refrigerating device in the present invention in detail with
reference to the drawings.
Embodiment 1
[0084] One embodiment of the present invention will be described in
detail with reference to the drawings. FIG. 1 shows a refrigerant
circuit diagram of a refrigerating device as one embodiment of the
present invention. A refrigerating device 30 is constituted of: a
compressor 1; a radiator 2 connected a discharge side of this
compressor 1; first heat absorbing means 10 and second heat
absorbing means 11 connected to an outlet side of this radiator 2;
and a cooling heat exchanger 32. The outlet side of the first heat
absorbing means 10 is connected to an intermediate-pressure portion
of the compressor 1, and the outlet side of the second heat
absorbing means 11 is connected to a suction side of the compressor
1 to constitute a refrigerating cycle.
[0085] The first heat absorbing means 10 includes: a first
expansion valve 65 in which a refrigerant from a branch point 9A
circulates; and a refrigerating heat sink 57. The second heat
absorbing means 11 includes: a second expansion valve 66 in which
the refrigerant from the branch point 9A circulates; and a freezing
heat sink 58.
[0086] The first heat absorbing means 10 and the second heat
absorbing means 11 function in different temperature zones. A
refrigerant pipe from the radiator 2 is branched from the branch
point 9A into one pipe as the first heat absorbing means 10 and the
other pipe as the second heat absorbing means 11. The connected
pipes are introduced into an intermediate-pressure portion and a
suction port of the compressor 1.
[0087] Here, the first and second expansion valves 65 and 66 are
constituted in such a manner that a throttle degree is variable.
This throttle degree is changed to lower a refrigerant pressure to
a predetermined pressure before the refrigerant reaches the heat
sinks 57, 58, and it is possible to control an evaporation
temperature of the refrigerant in the heat sinks 57, 58.
[0088] Moreover, in the present embodiment, the refrigerating
device 30 is provided with the cooling heat exchanger 32 and a
check valve 7 between the first heat absorbing means 10 and the
intermediate-pressure portion of the compressor 1, and a check
valve 52 is disposed between the second heat absorbing means 11 and
the suction side of the compressor 1.
[0089] The cooling heat exchanger 32 is disposed in order to
exchange heat between the refrigerant discharged from the radiator
2 and the refrigerant discharged from the heat sink 57. After the
refrigerant discharged from the heat sink 57 is discharged from the
cooling heat exchanger 32, the refrigerant is introduced into the
intermediate-pressure portion via a refrigerant introducing tube 6
connected to the intermediate-pressure portion of the compressor 1.
The refrigerant introducing tube 6 is provided with the check valve
7.
[0090] It is to be noted that as described above, the first
expansion valve 65 is constituted in such a manner that the
throttle degree is variable, and the throttle degree of the first
expansion valve 65 is changed to lower, to a predetermined
pressure, a pressure of the refrigerant entering the first heat
absorbing means 10 via the branch point 9A before the refrigerant
reaches the cooling heat exchanger 32. Moreover, the refrigerant
discharged from the first expansion valve 65 exchanges heat with
the refrigerant discharged from the radiator 2 in the cooling heat
exchanger 32, and is warmed to form a gas refrigerant. The
refrigerant is returned to the intermediate-pressure portion of the
compressor 1 via the refrigerant introducing tube 6.
[0091] The compressor 1 is a two-stage compressor including a
first-stage compressing section 1A and a second-stage compressing
section 1B in a sealed container. An intermediate cooling unit 1C
is disposed in a refrigerant pipe connecting the first-stage
compressing section 1A to the second-stage compressing section 1B
outside the sealed container. The refrigerant introducing tube 6 is
connected in such a manner that the gas refrigerant discharged from
the cooling heat exchanger 32 can be introduced into the
intermediate-pressure portion of the compressor 1, that is, between
the intermediate cooling unit 1C and the second-stage compressing
section 1B. It is to be noted that the gas refrigerant discharged
from the cooling heat exchanger 32 is introduced into the
intermediate-pressure portion of the compressor 1 owing to a
difference pressure in the refrigerant introducing tube 6 as shown
by a broken-line arrow. This compressor 1 is not limited to the
two-stage compressor. For example, in a single-stage compressor,
the refrigerant introducing tube 6 may be returned to the
intermediate-pressure portion of the single-stage compressor.
Alternatively, a plurality of compressors may be connected.
[0092] Further in the present embodiment, cold air passed through
the heat sink 57 is fed to a refrigerating room 21 via a duct 57A
by means of a fan 63 disposed in the vicinity of the heat sink 57,
and cold air passed through the heat sink 58 is fed to a freezing
room 22 via a duct 58A by means of a fan 64 disposed in the
vicinity of the freezing heat sink 58.
[0093] Here, in the refrigerating device 30 of the present
embodiment, as the refrigerant, there is used a carbon dioxide
refrigerant (CO.sub.2) which is a natural refrigerant having a
small environmental load in consideration of flammability, toxicity
and the like. As oil which is a lubricant of the compressor 1,
there is used, for example, mineral oil, alkyl benzene oil, ether
oil, ester oil, polyalkylene glycol (PAG), polyol ester (POE) or
the like.
[0094] There will be described an operation of the refrigerating
device 30 of the present embodiment constituted as described above
with reference to FIGS. 1 and 2. FIG. 2 is an enthalpy-pressure
(ph) chart of a refrigerating cycle in the present embodiment.
[0095] In the refrigerating device 30 of the present embodiment,
there are selected as required a freezing operation in which the
second heat absorbing means 11 mainly functions, and a freezing and
refrigerating operation in which the first heat absorbing means 10
and the second heat absorbing means 11 perform refrigerating and
freezing.
[0096] First, the freezing operation will be described with
reference to a cycle chart shown by a solid line in FIG. 2. It is
to be noted that this freezing operation refers to an operation in
which the above-described heat sink 58 is allowed to function at a
predetermined temperature (e.g., around -26.degree. C.) to cool the
freezing room 22 in a concentrated manner.
[0097] In the present embodiment, when the compressor 1 is
operated, the refrigerant discharged from the compressor 1 radiates
heat in the radiator 2, and is cooled. That is, the refrigerant is
first circulated in order of: (1) suction into the first-stage
compressing section 1A; (2) discharge from the first-stage
compressing section 1A; (3) suction into the second-stage
compressing section 1B; and
[0098] (4) discharge from the second-stage compressing section 1B.
Thereafter, the refrigerant flows through (5) an outlet of the
radiator 2 and an inlet to the cooling heat exchanger 32 and (7) an
outlet of the cooling heat exchanger 32 to reach the branch point
9A. The refrigerant is then branched, a part of the refrigerant
circulates in the first heat absorbing means 10, and the remaining
refrigerant circulates in the second heat absorbing means 11. It is
to be noted that the refrigerant discharged from the radiator 2 is
super-cooled by the cooling heat exchanger 32 before reaching the
branch point 9A. This respect will be described later in
detail.
[0099] The refrigerant circulated from the branch point 9A to the
first heat absorbing means 10 reaches (6) an outlet of the first
expansion valve 65 to form a two-phase mixture of gas and liquid.
Moreover, this refrigerant as the two-phase mixture flows into the
heat sink 57. In the present freezing operation, the fan 63
disposed in the vicinity of the heat sink 57 is stopped by a
control unit (not shown) to thereby substantially stop a heat
absorbing function of the heat sink 57. Accordingly, the
refrigerant discharged from the first expansion valve 65 hardly
absorbs heat from a surrounding area in the heat sink 57, and
reaches the cooling heat exchanger 32. In the cooling heat
exchanger 32, the refrigerant exchanges heat with the refrigerant
discharged from the radiator 2, and is warmed to form the gas
refrigerant. The refrigerant is introduced into the
intermediate-pressure portion of the compressor 1, that is, between
the intermediate cooling unit 1C and the second-stage compressing
section 1B via the refrigerant introducing tube 6. That is, (6)
indicates the outlet of the first expansion valve 65, and (21)
indicates the outlet of the cooling heat exchanger 32. The
refrigerant discharged from the outlet reaches (3) the suction into
the second-stage compressing section 1B, and is compressed in the
second-stage compressing section 1B. It is to be noted that the
refrigerant discharged from the radiator 2 is super-cooled by means
of the heat exchange in the cooling heat exchanger 32.
[0100] On the other hand, the refrigerant circulated from the
branch point 9A to the second heat absorbing means 11 exchanges
heat with the refrigerant circulated on the side of the first heat
absorbing means 10 as described above in the cooling heat exchanger
32, and the refrigerant is super-cooled. In this state, the
refrigerant reaches the second expansion valve 66. That is, the
refrigerant circulated on the side of the second heat absorbing
means 11 is circulated in order of: (7) an inlet to the second
expansion valve 66; (8) an outlet of the second expansion valve 66
and an inlet to the heat sink 58; and (22) an outlet of the heat
sink 58. It is to be noted that a liquid refrigerant which has
entered the heat sink 58 evaporates in the heat sink 58 to absorb
heat from the surrounding area because the fan 64 is operated by
the control unit (not shown). Thereafter, the refrigerant returns
to the suction port of the compressor 1. That is, (1) indicates the
suction into the first-stage compressing section 1A.
[0101] On the other hand, there is formed a cycle shown by a broken
line in FIG. 2 during the freezing and refrigerating. It is to be
noted that this freezing and refrigerating operation refers to an
operation in which the heat sinks 57 and 58 are operated (e.g., the
heat sink 57 around -5.degree. C. and the heat sink 58 around
-5.degree. C.) to cool the refrigerating room 21 and the freezing
room 22). Even in this case, when the compressor 1 is operated, the
refrigerant discharged from the compressor 1 radiates heat in the
radiator 2, and is cooled. That is, first the refrigerant is
circulated in order of: (1) suction into the first-stage
compressing section 1A; (2) discharge from the first-stage
compressing section 1A; (3) suction into the second-stage
compressing section 1B; and (4) discharge from the second-stage
compressing section 1B. Thereafter, the refrigerant flows from (5)
the outlet of the radiator 2 and the inlet to the cooling heat
exchanger 32 and (18) the outlet of the cooling heat exchanger 32
to reach the branch point 9A, and the refrigerant is then branched.
A part of the refrigerant circulates in the first heat absorbing
means 10, and the remaining refrigerant circulates in the second
heat absorbing means 11. It is to be noted that the refrigerant
discharged from the radiator 2 reaches the branch point 9A in a
state in which the refrigerant is super-cooled by the cooling heat
exchanger 32 in the same manner as in the freezing operation, and a
super-cooled degree is smaller than that during the freezing
operation. Details will be described later.
[0102] The refrigerant circulated from the branch point 9A to the
first heat absorbing means 10 reaches (16) the outlet of the first
expansion valve 65 to form a two-phase mixture of gas and liquid.
Moreover, this refrigerant as the two-phase mixture flows into the
heat sink 57. In the present freezing and refrigerating operation,
unlike the freezing operation, the fan 63 disposed in the vicinity
of the heat sink 57 is operated by the control unit (not shown) to
thereby operate the heat sink 57. Accordingly, after evaporating in
the heat sink 57 to absorb heat from the surrounding area, the
refrigerant discharged from the first expansion valve 65 reaches
the cooling heat exchanger 32, and exchanges heat with the
refrigerant discharged from the radiator 2 in the cooling heat
exchanger 32, and the refrigerant is warmed. The refrigerant in the
form of the gas refrigerant is introduced into the
intermediate-pressure portion of the compressor 1, that is, between
the intermediate cooling unit 1C and the second-stage compressing
section 1B via the refrigerant introducing tube 6. That is, (16)
indicates the outlet of the first expansion valve 65 and the inlet
to the heat sink 57, (21) indicates the outlet of the heat sink 57
and the inlet to the cooling heat exchanger 32, and (25) indicates
the outlet of the cooling heat exchanger 32. The refrigerant
discharged from the cooling heat exchanger reaches (3) the suction
port of the second-stage compressing section 1B, and is compressed
in the second-stage compressing section 1B. It is to be noted that
the refrigerant discharged from the radiator 2 is super-cooled by
means of the heat exchange in the cooling heat exchanger 32, but in
the present freezing and refrigerating operation, the heat
absorbing function of the heat sink 57 is exerted unlike the
freezing operation. Therefore, a heat exchange amount in the
cooling heat exchanger 32 is smaller than that during the freezing
operation. Accordingly, the super-cooled degree of the refrigerant
discharged from the radiator 2 is smaller than that during the
freezing operation.
[0103] On the other hand, the refrigerant circulated from the
branch point 9C to the second heat absorbing means 11 side
exchanges heat with the refrigerant circulated on the side of the
first heat absorbing means 10 in the cooling heat exchanger 32 as
described above, and the refrigerant in a super-cooled state
reaches the second expansion valve 66. That is, the refrigerant
circulated on the side of the second heat absorbing means 11 is
circulated in order of: (18) the inlet to the second expansion
valve 66: (15) the outlet of the second expansion valve 66 and the
inlet to the heat sink 58; and (22) the outlet of the heat sink 58.
Since the fan 64 is operated by the control unit (not shown), the
liquid refrigerant which has entered the heat sink 58 evaporates in
the heat sink 58 to absorb heat from the surrounding area.
Thereafter, the refrigerant returns to the suction port of the
compressor 1. That is, (1) indicates the suction into the
first-stage compressing section 1A. During both of the freezing
operation and the freezing and refrigerating operation, the
refrigerant circulates as described above to change its state, and
the refrigerating cycle is formed.
[0104] Here, in the present embodiment, since the carbon dioxide
refrigerant is introduced into the refrigerant circuit, a dry
degree of the refrigerant entering the expansion valves 65, 66 is
excessively high in the refrigerant circuit for use in a
conventional chlorofluorocarbon-based refrigerant or an HC-based
refrigerant, that is, the refrigerant circuit in which the
expansion valves 65, 66 are disposed immediately after the radiator
2 even in a case where the atmospheric temperature around the
radiator 2, that is, the temperature in (5) the outlet of the
radiator 2 in FIG. 2 is about +22.degree. C. as in the present
embodiment. Therefore, a ratio of the gas refrigerant in the
refrigerant is high, and it is difficult to obtain a sufficient
cooling performance.
[0105] To solve the problem, in the present embodiment, the
refrigerant pipe is branched from the branch point 9A, and one pipe
is provided with the first heat absorbing means 10 as well as the
cooling heat exchanger 32 to super-cool the refrigerant which has
entered the first and second heat absorbing means 10 and 11 in the
cooling heat exchanger 32. According to such constitution, a high
cooling effect can be obtained even in a case where the carbon
dioxide refrigerant having the above-described characteristics is
used. In this case, the refrigerant discharged from the side of the
first heat absorbing means 10 is introduced as the gas refrigerant
into the intermediate-pressure portion of the compressor 1.
Therefore, a compression efficiency in the compressor 1 can be
improved, and an efficiency of the refrigerating device 30 can
further be improved.
[0106] Moreover, during the freezing operation, unlike the freezing
and refrigerating operation, the fan 63 disposed in the vicinity of
the heat sink 57 is stopped to increase a heat exchange amount in
the cooling heat exchanger 32. According to this constitution, the
super-cooled degree of the refrigerant entering the second heat
absorbing means 11 can further be increased, and the freezing
operation can be performed with a higher efficiency.
[0107] Next, there will be described an example in which the
refrigerating device 30 of the present embodiment is applied to a
refrigerator with reference to FIG. 3.
[0108] FIG. 3 shows a schematic constitution diagram of the
refrigerator provided with the refrigerating device 30 of the
present embodiment. This refrigerator 40 is constituted of: a
refrigerating room 41 disposed in an upper stage; and a freezing
room 42 disposed in a lower stage. Moreover, refrigerator partition
walls 61, 62 are disposed in inner parts of the respective rooms
41, 42, and the heat sinks 57, 58 and fans 63, 64 are disposed in
air paths 44 defined by the refrigerator partition walls 61,
62.
[0109] In the present embodiment, since the refrigerator 40 is
provided with the refrigerating device 30 constituted as described
above, a high cooling performance and a high-efficiency operation
are possible even in a case where carbon dioxide is used in the
refrigerant.
Embodiment 2
[0110] Next, Embodiment 2 of the present invention will be
described with reference to FIG. 4. FIG. 4 shows a refrigerant
circuit diagram of a refrigerating device 50 in this case. The
present embodiment is different from Embodiment 1 in that a branch
point 9B is disposed halfway in a refrigerant introducing tube 6
between a cooling heat exchanger 32 and an intermediate-pressure
portion of a compressor 1. One pipe 6A is connected to the
intermediate-pressure portion of the compressor 1, that is, between
an intermediate cooling unit 1C and a second-stage compressing
section 1B in the compressor 1 in the same manner as in Embodiment
1. Moreover, the other pipe 6B is connected to a suction side of a
first-stage compressing section 1A in the compressor 1, and these
pipes 6A and 6B are provided with electromagnetic valves 8A and
8B.
[0111] Accordingly, in the refrigerating device 50 of the present
embodiment, a refrigerating operation can be executed in addition
to the freezing operation and the freezing and refrigerating
operation of Embodiment 1. That is, in the refrigerating operation
of the refrigerating device 50, a second expansion valve 66 of
second heat absorbing means his closed, the electromagnetic valve
8A is closed, and the electromagnetic valve 8B is opened to thereby
circulate a refrigerant on the side of first heat absorbing means
10 only. Moreover, a fan 63 disposed in the vicinity of a heat sink
57 is operated by a control unit (not shown) to thereby cool a
refrigerating room 21. It is to be noted that in this case, the
number of revolutions of the compressor 1 may be lowered if
necessary depending on a state of a cooling load or the like of the
refrigerating room 21. It is assumed that in the present
embodiment, the electromagnetic valve 8A is opened and the
electromagnetic valve 8B is closed during the freezing operation
and the freezing and refrigerating operation unlike the
refrigerating operation.
[0112] It is to be noted that the refrigerating device 50 of the
present embodiment can be applied to a refrigerator in the same
manner as in the refrigerating device 30 of Embodiment 1.
[0113] The present invention has been described above in accordance
with the embodiments, but the present invention is not limited to
the embodiments, and various modifications are possible. For
example, a carbon dioxide refrigerant is introduced into a
refrigerant circuit in the above-described embodiments, but the
present invention is not limited to the embodiments, and is
applicable to another embodiment in which a
chlorofluorocarbon-based refrigerant is introduced.
[0114] Moreover, the expansion valves 65 and 66 of the
above-described embodiments may be changed to capillary tubes if
necessary.
Embodiment 3
[0115] Next, Embodiment 3 of the present invention will be
described in detail with reference to the drawings. FIG. 5 shows a
refrigerant circuit diagram of a refrigerating device in the
present embodiment. A refrigerating device 30 is provided with: a
compressor 1; a radiator 2 connected to a discharge side of this
compressor 1; first heat absorbing means 10 and second heat
absorbing means 11 connected to an outlet side of this radiator 2;
and a cooling heat exchanger 32. An outlet side of the first heat
absorbing means 10 is connected to an intermediate-pressure portion
of the compressor 1, and an outlet side of the second heat
absorbing means 11 is connected to a suction port of the compressor
1 to constitute a refrigerating cycle.
[0116] Moreover, the refrigerating device 30 is provided with: a
check valve 7 disposed between the first heat absorbing means 10
and the intermediate-pressure portion of the compressor 1; a check
valve 52 and a heat exchanger 15 disposed between the second heat
absorbing means 11 and the suction port of the compressor 1; and a
control unit 26. The heat exchanger 15 is constituted in such a
manner that heat can be exchanged between a refrigerant discharged
from the second heat absorbing means and a refrigerant which is
going to enter a low-pressure expansion valve 65.
[0117] The first heat absorbing means 10 includes the
intermediate-pressure expansion valve 65 in which the refrigerant
from a branch point 9A circulates, and an intermediate-pressure
heat sink 57. The second heat absorbing means 11 includes a
low-pressure expansion valve 66 in which the refrigerant from the
branch point 9A circulates, and a low-pressure heat sink 58.
Moreover, the first heat absorbing means 10 and the second heat
absorbing means 11 function in different temperature zones, a
refrigerant pipe from the radiator 2 is branched at the branch
point 9A, one pipe is connected to the first heat absorbing means
10, and the other pipe is connected to the second heat absorbing
means 11.
[0118] The intermediate-pressure expansion valve 65 and the
low-pressure expansion valve 66 are constituted in such a manner
that a throttle degree is variable. This throttle degree is changed
to lower a refrigerant pressure to a predetermined pressure before
the refrigerant reaches the heat sinks 57, 58, and it is possible
to control an evaporation temperature of the refrigerant in the
heat sinks 57, 58.
[0119] The cooling heat exchanger 32 is disposed in order to
exchange heat between the refrigerant discharged from the radiator
2 and the refrigerant discharged from the intermediate-pressure
heat sink 57. After the refrigerant discharged from the
intermediate-pressure heat sink 57 is discharged from the cooling
heat exchanger 32, the refrigerant is introduced into the
intermediate-pressure portion of the compressor 1 via the check
valve 7.
[0120] It is to be noted that since the expansion valve 65 is
constituted so that the throttle degree is variable as described
above, the throttle degree of this intermediate-pressure expansion
valve 65 is changed to lower, to a predetermined pressure, a
pressure of the refrigerant circulated from the branch point 9A to
the intermediate-pressure expansion valve 65 before the refrigerant
reaches the intermediate-pressure heat sink 57.
[0121] The compressor 1 is a two-stage compressor including a
first-stage compressing section 1A as a front-stage compression
element and a second-stage compressing section 1B as a rear-stage
compression element in a sealed container. An intermediate cooling
unit 1C is disposed in a refrigerant pipe of the first-stage
compressing section 1A on a discharge side. It is to be noted that
the gas refrigerant discharged from the first heat absorbing means
10 and passed through the cooling heat exchanger 32 is introduced
between the intermediate cooling unit 1C and the suction port of
the second-stage compressing section 1B.
[0122] Further in the refrigerating device 30 of the present
embodiment, cold air passed through the intermediate heat sink 57
is fed to a refrigerating room 21 via a duct 57A by means of a fan
57F disposed in the vicinity of the heat sink 57, and cold air
passed through the low-pressure heat sink 58 is fed to a freezing
room 22 via a duct 58A by means of a fan 58F disposed in the
vicinity of the heat sink 58.
[0123] The control unit 26 is control means for controlling an
operation frequency or an ON-OFF state of the compressor 1, open
degrees of the expansion valves 65 and 66, ON-OFF states of the
fans 57F and 58F and the like based on information of temperature
sensors 21T and 22T disposed in the refrigerating room 21 and the
freezing room 22, respectively. The unit is constituted of a
general-purpose microcomputer.
[0124] It is to be noted that in the present embodiment, in FIG. 5,
a high-pressure part of a refrigerating cycle of the refrigerating
device 30 is operated which corresponds to a part from the
discharge side of the second-stage compressing section 1B to inlets
to the intermediate-pressure expansion valve 65 and the
low-pressure expansion valve 66 via the radiator 2 and the cooling
heat exchanger 32. An intermediate-pressure part of the
refrigerating cycle of the refrigerating device 30 is operated
which corresponds to a part from the discharge side of the
first-stage compressing section 1A to the suction port of the
second-stage compressing section 1B via the intermediate cooling
unit 1C, and the outlet of the intermediate-pressure expansion
valve 65 to the suction port of the second-stage compressing
section 1B via the intermediate-pressure heat sink 57 and the
cooling heat exchanger 32. Moreover, a low-pressure part of the
refrigerating cycle of the refrigerating device 30 is operated
which corresponds to a part from the outlet of the low-pressure
expansion valve 66 to the suction port of the first-stage
compressing section 1A via the low-pressure heat sink 58 and the
heat exchanger 15.
[0125] Here, the compressor 1 of the present embodiment will be
described with reference to FIG. 6. FIG. 6 is a schematic sectional
view of the compressor 1.
[0126] The compressor 1 is a high inner pressure type two-stage
compression system rotary compressor. The compressor 1 is provided
with a sealed container 112 whose upper and lower ends are both
sealed and which substantially has a vertically long cylindrical
shape. A bottom portion of this sealed container 112 is constituted
as an oil reservoir. The sealed container 112 includes: an
electromotive element 114; and a rotary compressing section 118
constituted of a first compressing section 1A and a second
compressing section 1B driven via a rotation shaft 116 of the
electromotive element 114, and an outer face of a bottom of the
container is provided with leg portions 210 for fixing the
compressor 1 to, for example, a refrigerator housing (not
shown).
[0127] The sealed container 112 is constituted of: a container main
body 112A which stores the electromotive element 114 and the rotary
compressing section 118; and an end cap (lid member) 112B which
closes an end portion of this container main body 112A on the side
of the electromotive element 114. A circular attachment hole 112D
is formed in this end cap 112B, and a terminal 120 (wiring line is
omitted) for supplying power to the electromotive element 114 is
attached to the attachment hole 112D.
[0128] The electromotive element 114 is constituted of: a stator
122 annularly attached along an inner peripheral face of the sealed
container 112; and a rotor 124 inserted in the electromotive
element and internally disposed at a slight interval from the inner
peripheral face of this stator 122. This rotor 124 is fixed to the
rotation shaft 116 which passes through the center and which
extends in an axial center direction of the sealed container 112.
Here, the stator 122 has: a laminate (not shown) constituted of
laminated donut-shaped electromagnetic steel plates; and a stator
coil 128 wound around a tooth portion of this laminate by a direct
winding method. Moreover, the rotor 124 is formed of a laminate of
electromagnetic steel plates in the same manner as in the stator
122. The rotor is formed by inserting a permanent magnet in this
laminate.
[0129] Moreover, in the rotation shaft 116, an oil passage 182
extends through the axial center of the shaft in a perpendicular
direction. One end of this oil passage 182 on the side of the
rotary compressing section 118 opens to the oil reservoir which is
the bottom portion of the sealed container 112. The other end of
the passage on the side of the electromotive element 114 opens on
the side of the end cap 112B. It is to be noted that this oil
passage 182 communicates with sliding portions of the respective
compressing sections 1A, 1B, and is connected to the compressing
sections 1A, 1B so that oil can be supplied.
[0130] The first-stage compressing section 1A and the second-stage
compressing section 1B of the rotary compressing section 118 are
constituted of first and second cylinders 138, 140, and an
intermediate partition plate 136 is sandwiched between these
cylinders 138 and 140. The respective compressing sections 1A, 1B
are constituted of: first and second rollers 146, 148 which are
fitted into the first and second cylinders 138, 140 disposed on
opposite sides (upper and lower sides in FIG. 5) of the
intermediate partition plate 136 and first and second eccentric
sections 142, 144 disposed on the rotation shaft 116 and having a
phase difference of 180 degrees and which eccentrically rotate in
the first and second cylinders 138, 140; first and second vanes
150, 152 which abut on these rollers 146, 148, respectively, to
define low-pressure and high-pressure chamber sides in the
cylinders 138, 140; and support members 154, 156 which close an
open face of the cylinder 140 on the side of the electromotive
element 114 and an open face of the cylinder 138 on the side
opposite to the electromotive element 114 and which also function
as bearings of the rotation shaft 116.
[0131] Outside the vanes 150, 152 (the right side in FIG. 5), there
are arranged springs 174, 176 which abut on outer end portions of
the vanes 150, 152 to urge the vanes 150, 152 toward the rollers
146, 148. Furthermore, the springs 174, 176 are provided with plugs
222, 223 made of metals on the side of the sealed container 112,
and the plugs prevent the springs 174, 176 from being disengaged. A
back pressure chamber (not shown) is constituted in the second vane
152, and a pressure on the side of the high-pressure chamber of the
cylinder 140 is applied as a back pressure to this back pressure
chamber.
[0132] The support members 154, 156 are provided with discharge
noise absorbing chambers 162, 164 formed by partially depressing
the members and closing the depressed portions with a baffle plate
200 and a cover 168, respectively. That is, the discharge noise
absorbing chamber 162 is formed by closing the depressed portion of
the support member 154 with the baffle plate 200, and the discharge
noise absorbing chamber 164 is formed by closing the depressed
portion of the support member 156 with the cover 168. Furthermore,
the support member 156 on the side of the first-stage compressing
section 1A is provided with an oil discharge chamber 167 formed by
depressing a portion other than the discharge noise absorbing
chamber 164 of the support member 156 and closing the portion with
the cover 168 in the same manner as in the discharge noise
absorbing chamber 164.
[0133] Moreover, in the respective compressing sections 1A, 1B,
spaces formed between the cylinders 138, 140 and the rollers 146,
148 and between the cylinders and the vanes 150, 152 are closed
with the support members 156, 154 and the intermediate partition
plate 136 to thereby constitute a compression chamber which sucks
and compresses the refrigerant.
[0134] Here, a rear-stage discharge port 160 is disposed between
the compression chamber of the second-stage compressing section 1B
and the discharge noise absorbing chamber 162, and provided with a
rear-stage discharge valve 161 which is opened in a case where the
refrigerant in the compression chamber reaches a predetermined
pressure. A front-stage discharge port 163 is disposed between the
compression chamber of the first-stage compressing section 1A and
the discharge noise absorbing chamber 164, and provided with a
front-stage discharge valve 165 which is opened in a case where the
refrigerant in the compression chamber reaches a predetermined
pressure.
[0135] Furthermore, an oil discharge port 171 is disposed between
the compression chamber of the first-stage compressing section 1A
and the oil discharge chamber 167, and provided with an oil
discharge valve 166 which is opened in a case where a large amount
of oil is sucked to cause liquid compression in the compression
chamber and the predetermined pressure is reached. This oil
discharge valve 166 is closed by the back pressure due to the
high-pressure refrigerant discharged from the second-stage
compressing section 1B, and the oil discharge chamber 167 is
provided with a valve back pressure inflow tube 170 which
communicates with the inside of the sealed container 112. The
high-pressure refrigerant is discharged from the second-stage
compressing section 1B into the sealed container 112 via a
discharge pipeline 221 described later to close the oil discharge
valve 166 via the valve back pressure inflow tube 170.
[0136] The discharge noise absorbing chamber 162 communicates with
the sealed container 112 via the discharge pipeline 221 extending
through the baffle plate 200 to open on the side of the
electromotive element 114. The high-pressure refrigerant gas
compressed in the second-stage compressing section 1B is discharged
toward the electromotive element 114 in the sealed container 112
via the discharge pipeline 221. In this case, the refrigerant gas
is mixed with the oil supplied to the second-stage compressing
section 1B, but this oil is also discharged toward the
electromotive element 114 in the sealed container 112. Moreover,
the oil mixed in the refrigerant gas is separated from the
refrigerant gas, and stored in the oil reservoir which is the
bottom portion of the sealed container 112.
[0137] Moreover, the sealed container 112 is connected to: a
refrigerant introducing tube 194 for introducing the refrigerant
gas into the first-stage compressing section 1A; an intermediate
refrigerant discharge tube 192 which discharges, to the outside of
the sealed container 112, the refrigerant gas compressed in the
first-stage compressing section 1A to obtain an intermediate
pressure; an intermediate refrigerant introducing tube 193 which
introduces the intermediate-pressure refrigerant discharged from
the intermediate refrigerant discharge tube 192 into the
second-stage compressing section 1B via the intermediate cooling
unit 1C as described above; and a refrigerant discharge tube 196
for discharging, from the compressor 1, the refrigerant gas
compressed in the second-stage compressing section 1B under the
high pressure and discharged into the sealed container 112 via the
discharge pipeline 221 as described above. The connected tubes are
inserted in the sealed container.
[0138] Furthermore, in the refrigerating device 30 of the present
embodiment, as the refrigerant, there is used a carbon dioxide
refrigerant (CO.sub.2) which is a natural refrigerant having a
small environmental load in consideration of flammability, toxicity
and the like. As oil which is a lubricant of the compressor 1,
there is used, for example, mineral oil, alkyl benzene oil, ether
oil, polyalkylene glycol (PAG), polyol ester (POE) or the like.
[0139] Since carbon dioxide is used in the refrigerating device 30
in this manner, the high pressure part of the refrigerating cycle
is brought into a supercritical state in a case where an outside
air temperature is not less than a critical temperature (about
+31.degree. C.) of carbon dioxide. Accordingly, the refrigerating
device 30 is operated as a transfer critical cycle.
[0140] There will be described an operation of the refrigerating
device 30 constituted as described above in the present embodiment
with reference to FIG. 5. The control unit 26 selectively allows
the refrigerating device 30 to perform the freezing operation
allowing the second heat absorbing means 11 to function, the
freezing and refrigerating operation allowing the first heat
absorbing means 10 and the second heat absorbing means 11 to
function, and the refrigerating operation allowing the first heat
absorbing means 10 to function.
[0141] First, the freezing operation will be described. It is to be
noted that this freezing operation is an operation allowing the
low-pressure heat sink 58 to function at a predetermined
temperature (e.g., around -26.degree. C.) and cool the freezing
room 22.
[0142] In the refrigerating device 30 of the present embodiment,
when the compressor 1 is operated, the intermediate-pressure
refrigerant compressed and discharged from the first-stage
compressing section 1A is cooled in the intermediate cooling unit
1C. Thereafter, the refrigerant is further compressed and
discharged from the second-stage compressing section 1B to radiate
heat in the radiator 2, and is cooled. Thereafter, the refrigerant
discharged from the radiator 2 reaches the branch point 9A via the
cooling heat exchanger 32, and is branched at the point. A part of
the refrigerant circulates to the first heat absorbing means 10,
and the remaining refrigerant circulates to the second heat
absorbing means 11. It is to be noted that the refrigerant
discharged from the radiator 2 is super-cooled by the cooling heat
exchanger 32 to reach the branch point 9A in this state.
[0143] A pressure of the refrigerant circulated from the branch
point 9A to the first heat absorbing means 10 is reduced by the
expansion valve 65, and the refrigerant forms a two-phase mixture
(gas/liquid mixed state) of gas and liquid. Moreover, this
refrigerant flows into the intermediate-pressure heat sink 57 in
the form of the two-phase mixture. However, in the present freezing
operation, the control unit 26 stops the fan 57F disposed in the
vicinity of the intermediate-pressure heat sink 57 to thereby
substantially stop the heat absorbing function of the heat sink
57.
[0144] Accordingly, the refrigerant discharged from the
intermediate expansion valve 65 hardly absorbs heat from the
surrounding area in the intermediate-pressure heat sink 57, and
reaches the cooling heat exchanger 32. In the cooling heat
exchanger 32, the refrigerant exchanges heat with the refrigerant
discharged from the radiator 2, and is warmed to form the gas
refrigerant. The refrigerant is introduced into the
intermediate-pressure portion of the compressor 1, that is, the
suction port of the second-stage compressing section 1B. It is to
be noted that the refrigerant discharged from the compressor 1 and
the radiator 2 is super-cooled by the refrigerant discharged from
the intermediate-pressure heat sink 57 by means of the heat
exchange in the cooling heat exchanger 32.
[0145] On the other hand, the refrigerant circulated from the
branch point 9A to the second heat absorbing means 11 side
exchanges heat with the refrigerant circulated on the side of the
first heat absorbing means 10 as described above in the cooling
heat exchanger 32, and the super-cooled refrigerant reaches the
low-pressure expansion valve 66. Here, the pressure of the
refrigerant is reduced to form the two-phase mixture of gas and
liquid. Moreover, since the fan 58F is operated by the control unit
26, the refrigerant which has entered the low-pressure heat sink 58
evaporates in the heat sink 58 to absorb heat from the surrounding
area. Thereafter, in the heat exchanger 15, the refrigerant
exchanges heat with the refrigerant which is to enter the
low-pressure expansion valve 66, and is warmed. The refrigerant
returns to the suction port of the compressor 1. It is to be noted
that after the refrigerant is super-cooled in the cooling heat
exchanger 32 by means of the above-described heat exchange in the
heat exchanger 15, the refrigerant flowing into the low-pressure
expansion valve 66 via the branch point 9A is further cooled.
[0146] Next, the freezing and refrigerating operation will be
described. It is to be noted that this freezing and refrigerating
operation is an operation allowing the intermediate-pressure heat
sink 57 and the low-pressure heat sink 58 at predetermined
temperatures (e.g., the intermediate-pressure heat sink 57 around
-5.degree. C., the low-pressure heat sink 58 around -26.degree. C.)
to cool the refrigerating room 21 and the freezing room 22.
[0147] Even in this case, when the compressor 1 is operated, the
intermediate-pressure refrigerant compressed and discharged from
the first-stage compressing section 1A is cooled by the
intermediate cooling unit 1C. Thereafter, the refrigerant is
further compressed and discharged from the second-stage compressing
section 1B to radiate heat in the radiator 2, and is cooled.
Thereafter, the refrigerant discharged from the radiator 2 reaches
the branch point 9A via the cooling heat exchanger 32, and is
branched here. A part of the refrigerant circulates in the first
heat absorbing means 10, and the remaining refrigerant circulates
in the second heat absorbing means 11. It is to be noted that the
refrigerant discharged from the radiator 2 is super-cooled in the
cooling heat exchanger 32, and reaches the branch point 9A in this
state in the same manner as in the above-described freezing
operation.
[0148] The pressure of the refrigerant circulated from the branch
point 9A to the first heat absorbing means 10 is reduced by the
intermediate-pressure expansion valve 65 to obtain the two-phase
mixture of gas and liquid. Moreover, this refrigerant flows into
the intermediate-pressure heat sink 57 in the form of the two-phase
mixture. However, in the present freezing and refrigerating
operation, the control unit 26 stops the fan 57F disposed in the
vicinity of the intermediate-pressure heat sink 57 to thereby exert
the heat absorbing function of the heat sink 57 unlike the
above-described freezing operation.
[0149] Accordingly, the refrigerant discharged from the
intermediate-pressure expansion valve 65 evaporates in the
intermediate-pressure heat sink 57 to absorb heat from the
surrounding area, and reaches the cooling heat exchanger 32. In the
cooling heat exchanger 32, the refrigerant exchanges heat with the
refrigerant discharged from the radiator 2, and is introduced into
the suction port of the second-stage compressing section 1B in the
form of the gas refrigerant.
[0150] On the other hand, the refrigerant circulated from the
branch point 9A to the second heat absorbing means 11 side
exchanges heat with the refrigerant circulated on the side of the
first heat absorbing means 10 as described above in the cooling
heat exchanger 32, and the super-cooled refrigerant reaches the
low-pressure expansion valve 66. Here, the pressure of the
refrigerant is reduced to obtain the two-phase mixture of gas and
liquid. Moreover, in this case, since the fan 58F is operated by
the control unit 26, the refrigerant which has entered the
low-pressure heat sink 58 evaporates in the heat sink 58 to absorb
heat from the surrounding area. Thereafter, the refrigerant passes
through the heat exchanger 15, and returns to the suction port of
the compressor 1.
[0151] The refrigerating operation will be described. It is to be
noted that this refrigerating operation is an operation allowing
the intermediate-pressure heat sink 57 to function at a
predetermined temperature (e.g., around -5.degree. C.) and cool the
refrigerating room 21. In the present refrigerating operation, the
control unit 26 closes the low-pressure expansion valve 66 to
interrupt refrigerant circulation from the branch point 9A to the
second heat absorbing means 11 side, and the refrigerant is
circulated on the first heat absorbing means 10 side only.
[0152] In this case, when the compressor 1 is operated, the
refrigerant compressed and discharged from the second-stage
compressing section 1B radiates heat, and is cooled in the radiator
2. Thereafter, the refrigerant discharged from the radiator 2
passes through the cooling heat exchanger 32 and the branch point
9A to circulate in the first heat absorbing means 10.
[0153] The pressure of the refrigerant circulated from the branch
point 9A in the first heat absorbing means 10 is reduced by the
intermediate-pressure expansion valve 65 to obtain the two-phase
mixture (gas/liquid mixed state) of gas and liquid. Moreover, this
refrigerant flows into the heat sink 57 in the form of the
two-phase mixture, but in the present refrigerating operation, the
fan 57F disposed in the vicinity of the intermediate-pressure heat
sink 57 is operated by the control unit 26, thereby exerting the
heat absorbing function of the heat sink 57.
[0154] Accordingly, the refrigerant discharged from the expansion
valve 65 evaporates in the intermediate-pressure heat sink 57 to
absorb heat from the surrounding area. Thereafter, the refrigerant
reaches the cooling heat exchanger 32, and exchanges heat with the
refrigerant discharged from the radiator 2 in the cooling heat
exchanger 32. The refrigerant is thus warmed to form the gas
refrigerant, and introduced into the suction port of the
second-stage compressing section 1B. It is to be noted that the
refrigerant discharged from the compressor 1 and the radiator 2 is
super-cooled by the refrigerant discharged from the
intermediate-pressure heat sink 57 by means of the heat exchange in
the cooling heat exchanger 32 as described above.
[0155] In addition, in the present refrigerating operation, while
the compressor 1 is operated, the circulation of the refrigerant
from the branch point 9A to the second heat absorbing means 11 is
interrupted to stop the cooling function of the second heat
absorbing means 11. Therefore, a vacuum state is substantially
brought from the low-pressure expansion valve 66 to the compression
chamber of the first-stage compressing section 1A via the
low-pressure heat sink 58. Accordingly, a large amount of oil flows
into the compression chamber of the first-stage compressing section
1A to cause liquid compression, and a compressor efficiency largely
deteriorates.
[0156] To solve the problem, in the compressor 1 of the present
embodiment, the first-stage compressing section 1A is constituted
as shown in FIG. 7 in order to inhibit the deterioration of the
compressor efficiency due to the above-described liquid compression
even in a case where the compression chamber of the first-stage
compressing section 1A is substantially brought into the vacuum
state during the present refrigerating operation. There will be
described hereinafter the first-stage compressing section 1A in the
compressor 1 of the present embodiment with reference to FIG. 7. It
is to be noted that FIG. 7 is a plan view schematically showing the
first-stage compressing section 1A of the compressor in the present
embodiment.
[0157] The support member 156 of the first-stage compressing
section 1A is provided with: the discharge noise absorbing chamber
164 for passing the refrigerant compressed in the first-stage
compressing section 1A and discharged from the front-stage
discharge port 163; and the front-stage discharge valve 165 which
controls the circulation of the refrigerant to the discharge noise
absorbing chamber 164.
[0158] Furthermore, the support member 156 includes: the oil
discharge port 171 for discharging oil as a cause for the liquid
compression from the compression chamber before the above-described
liquid compression occurs in the compression chamber of the
first-stage compressing section 1A; and the oil discharge chamber
167 which passes the oil discharged from this oil discharge port
171; and the oil discharge valve 166 which is constituted of a
spring-leaf-like member and which controls the oil discharge to the
oil discharge chamber 167.
[0159] An end portion of the front-stage discharge valve 165 on the
side opposite to the front-stage discharge port 163 is fixed to the
support member 156 via a valve support portion 165S. Accordingly,
when the pressure of the refrigerant compressed in the compression
chamber of the first-stage compressing section 1A becomes higher
than a predetermined open pressure of the front-stage discharge
valve 165 via the front-stage discharge port 163, the discharge
valve 165 is opened using the valve support portion 165S as a point
of support, and the refrigerant flows into the discharge noise
absorbing chamber 164. Moreover, the refrigerant which has entered
this discharge noise absorbing chamber 164 is discharged from the
first-stage compressing section 1A.
[0160] On the other hand, an end portion of the oil discharge valve
166 on the side opposite to the oil discharge port 171 is fixed to
the support member 156 via a valve support portion 166S. Moreover,
as described above, the oil discharge chamber 167 communicates with
the valve back pressure inflow tube 170 into which a high-pressure
refrigerant flows. The refrigerant has been compressed in the
second-stage compressing section 1B and discharged to the sealed
container 112. Therefore, when the compressor 1 is driven, the
pressure in the oil discharge chamber 167 is substantially equal to
that of the refrigerant discharged from the second-stage
compressing section 1B. The oil discharge valve 166 is closed by
this high back pressure.
[0161] Accordingly, during the freezing operation and the freezing
and refrigerating operation, the pressure of the refrigerant
discharged from the second-stage compressing section 1B is higher
than that of the refrigerant discharged from the first-stage
compressing section 1A. Therefore, the oil discharge valve 166 is
not opened, and the compressor 1 executes a usual two-stage
compressing operation.
[0162] On the other hand, during the present refrigerating
operation, in a case where the compression chamber of the
first-stage compressing section 1A is substantially brought into a
vacuum state, the liquid compression occurs, and the inside of the
compression chamber is brought into an abnormally high pressure
state, the oil discharge port 171 is opened, and the oil is
discharged from the oil discharge port 171 into the oil discharge
chamber 167. Accordingly, the above-described liquid compression is
remarkably inhibited, and remarkable deterioration of the
compressor efficiency can be prevented.
[0163] During all of the freezing operation, the freezing and
refrigerating operation, and the refrigerating operation, the
refrigerant circulates as described above to change its state,
thereby forming the refrigerating cycle.
[0164] Here, in the present embodiment, since the carbon dioxide
refrigerant is introduced into the refrigerant circuit, a dry
degree of the refrigerant entering the expansion valves 65, 66 is
excessively high in the refrigerant circuit for use in a
conventional chlorofluorocarbon-based refrigerant or an HC-based
refrigerant, that is, the refrigerant circuit in which the
expansion valves 65, 66 are disposed immediately after the radiator
2 even in a case where the outside air temperature is about
+22.degree. C. Therefore, a ratio of the gas refrigerant in the
refrigerant is high, and it is difficult to obtain a sufficient
cooling performance.
[0165] To solve the problem, in the refrigerating device 30, the
refrigerant pipe is branched from the branch point 9A, and one pipe
is provided with the first heat absorbing means 10 as well as the
cooling heat exchanger 32 to super-cool the refrigerant flowing
into the first and second heat absorbing means 10 and 11 in the
cooling heat exchanger 32. According to such constitution, a high
cooling effect can be obtained even in a case where the carbon
dioxide refrigerant having the above-described characteristics is
used. In this case, the refrigerant discharged from the side of the
first heat absorbing means 10 is introduced as the gas refrigerant
into the suction port of the second-stage compressing section 1B.
Therefore, a compression efficiency in the compressor 1 can be
improved, and a refrigerating cycle efficiency of the refrigerating
device 30 can further be improved.
[0166] Moreover, during the freezing operation, unlike the freezing
and refrigerating operation, the control unit 26 stops the fan 57F
disposed in the vicinity of the heat sink 57 to increase a heat
exchange amount in the cooling heat exchanger 32. According to this
constitution, it is possible to increase a super-cooling effect of
the refrigerant flowing into the second heat absorbing means 11,
and it is possible to perform a higher-efficiency freezing
operation.
[0167] Furthermore, in the present embodiment, the refrigerating
device 30 is constituted of the oil discharge port 171, the oil
discharge valve 166 and the like in the first-stage compressing
section 1A of the compressor 1. Therefore, even in a case where the
compressor 1 as a multistage compressor is used, it is possible to
inhibit the remarkable deterioration of the compressor efficiency
due to the liquid compression in the first-stage compressing
section 1A which is a front-stage compression element. It is
possible to inhibit energy wasting, and the high-efficiency
refrigerating operation is possible.
[0168] Next, there will be described an application example of the
refrigerating device 30 to a refrigerator in the present embodiment
with reference to FIG. 8. FIG. 8 shows a schematic constitution
diagram of the refrigerator provided with the refrigerating device
30.
[0169] A refrigerator 40 is constituted of: a refrigerating room 41
disposed in an upper stage; and a freezing room 42 disposed in a
lower stage. Moreover, refrigerator partition walls 61, 62 are
disposed in inner parts of the respective rooms 41, 42, and there
are arranged the intermediate-pressure heat sink 57, the
low-pressure heat sink 58, and the fans 63, 64 in air paths 44
defined by the refrigerator partition walls 61, 62. Moreover, the
freezing room 42 is provided with a temperature sensor 42T, and the
refrigerating room 41 is provided with a temperature sensor
41T.
[0170] Furthermore, during each above-described operation, that is,
during the freezing operation, the fan 64 is operated. During the
freezing and refrigerating operation, the fans 63, 64 are operated.
Further during the refrigerating operation, the fan 63 is operated.
This can cool the respective rooms 41, 42.
[0171] In the present embodiment, since the refrigerator 40 is
provided with the above-described constitution, a high cooling
performance and a high-efficiency operation are possible even in a
case where carbon dioxide is used in the refrigerant. Even during
the refrigerating operation, it is possible to inhibit the liquid
compression in the first-stage compressing section 1A of the
compressor 1, and the refrigerating cycle efficiency can be
improved.
[0172] The present invention has been described above in accordance
with the embodiment, but the present invention is not limited to
this embodiment, and various modifications are possible. For
example, the carbon dioxide refrigerant is introduced into the
refrigerant circuit in the above-described embodiment, but the
present invention is not limited to the embodiment, and is
applicable to another embodiment in which a
chlorofluorocarbon-based refrigerant is introduced.
[0173] Moreover, the expansion valves 65 and 66 of the
above-described embodiment may be changed to capillary tubes if
necessary.
Embodiment 4
[0174] Next, Embodiment 4 of the present invention will be
described in detail with reference to the drawings. FIG. 9 shows a
refrigerant circuit diagram of a refrigerating device in the
present embodiment. A refrigerating device 30 is provided with: a
compressor 100 as a front-stage compression element; a compressor
200 as a rear-stage compression element connected in series to the
discharge side of this compressor 100; a radiator 2 connected to
the discharge side of this compressor 200; first heat absorbing
means 10 and second heat absorbing means 11 connected to an outlet
side of this radiator 2; and a cooling heat exchanger 32. An outlet
side of the first heat absorbing means 10 is connected to a suction
port of the compressor 200, and an outlet side of the second heat
absorbing means 11 is connected to a suction port of the compressor
100 to constitute a refrigerating cycle.
[0175] Moreover, the refrigerating device 30 is provided with: a
check valve 7 disposed between the first heat absorbing means 10
and an intermediate-pressure portion of the compressor 1; a check
valve 52 and a heat exchanger 15 disposed between the second heat
absorbing means 11 and the suction port of the compressor 100; and
a control unit 26. The heat exchanger 15 is constituted in such a
manner that heat can be exchanged between a refrigerant discharged
from the second heat absorbing means and a refrigerant which is to
enter a low-pressure expansion valve 65.
[0176] The first heat absorbing means 10 includes the
intermediate-pressure expansion valve 65 in which the refrigerant
from a branch point 9A circulates, and an intermediate-pressure
heat sink 57. The second heat absorbing means 11 includes a
low-pressure expansion valve 66 in which the refrigerant from the
branch point 9A circulates, and a low-pressure heat sink 58.
Moreover, the first heat absorbing means 10 and the second heat
absorbing means 11 function in different temperature zones, a
refrigerant pipe from the radiator 2 is branched at the branch
point 9A, one pipe is connected to the first heat absorbing means
10, and the other pipe is connected to the second heat absorbing
means 11.
[0177] The intermediate-pressure expansion valve 65 and the
low-pressure expansion valve 66 are constituted in such a manner
that a throttle degree is variable. This throttle degree is changed
to lower a refrigerant pressure to a predetermined pressure before
the refrigerant reaches the heat sinks 57, 58, and it is possible
to control an evaporation temperature of the refrigerant in the
heat sinks 57, 58.
[0178] The cooling heat exchanger 32 is disposed in order to
exchange heat between the refrigerant discharged from the radiator
2 and the refrigerant discharged from the intermediate-pressure
heat sink 57. After the refrigerant discharged from the
intermediate-pressure heat sink 57 is discharged from the cooling
heat exchanger 32, the refrigerant is introduced into the suction
port of the compressor 200 via the check valve 7.
[0179] It is to be noted that since the expansion valve 65 is
constituted so that the throttle degree is variable as described
above, the throttle degree of this intermediate-pressure expansion
valve 65 is changed to lower, to a predetermined pressure, a
pressure of the refrigerant circulated from the branch point 9A to
the intermediate-pressure expansion valve 65 before the refrigerant
reaches the intermediate-pressure heat sink 57. Moreover, the
refrigerant discharged from the intermediate-pressure expansion
valve 65 evaporates in the intermediate-pressure heat sink 57 to
absorb heat from a surrounding area of the heat sink 57.
Thereafter, the refrigerant exchanges heat with the refrigerant
discharged from the radiator 2, and is warmed in the cooling heat
exchanger 32. Thereafter, the refrigerant is returned to the
suction port of the compressor 200.
[0180] The compressor 100 is connected in series to the compressor
200 as described above. An intermediate cooling unit 1C is disposed
in a refrigerant pipe which connects the discharge port of the
compressor 100 to the suction port of the compressor 100. It is to
be noted that the gas refrigerant discharged from the first heat
absorbing means 10 and passed through the cooling heat exchanger 32
is introduced between the intermediate cooling unit 1C and the
compressor 200.
[0181] Further in the refrigerating device 30 of the present
embodiment, cold air passed through the intermediate heat sink 57
is fed to a refrigerating room 21 via a duct 57A by means of a fan
57F disposed in the vicinity of the heat sink 57, and cold air
passed through the low-pressure heat sink 58 is fed to a freezing
room 22 via a duct 58A by means of a fan 58F disposed in the
vicinity of the heat sink 58.
[0182] The control unit 26 is control means for controlling
operation frequencies or ON-OFF states of the compressors 100, 200,
open degrees of the expansion valves 65 and 66, ON-OFF states of
the fans 57F and 58F and the like based on information of
temperature sensors 21T and 22T disposed in the refrigerating room
21 and the freezing room 22, respectively. The unit is constituted
of a general-purpose microcomputer.
[0183] It is to be noted that in the present embodiment, in FIG. 9,
a high-pressure part of a refrigerating cycle of the refrigerating
device 30 is operated which corresponds to a part from the
discharge side of the compressor 200 to inlets to the
intermediate-pressure expansion valve 65 and the low-pressure
expansion valve 66 via the radiator 2 and the cooling heat
exchanger 32. An intermediate-pressure part of the refrigerating
cycle of the refrigerating device 30 is operated which corresponds
to a part from the discharge side of the compressor 100 to the
suction port of the compressor 200 via the intermediate cooling
unit 1C, and the outlet of the intermediate-pressure expansion
valve 65 to the suction port of the compressor 200 via the
intermediate-pressure heat sink 57 and the cooling heat exchanger
32. Moreover, a low-pressure part of the refrigerating cycle of the
refrigerating device 30 is operated which corresponds to a part
from the outlet of the low-pressure expansion valve 66 to the
suction port of the compressor 100 via the low-pressure heat sink
58 and the heat exchanger 15.
[0184] Here, in the refrigerating device 30 of the present
embodiment, as the refrigerant, there is used a carbon dioxide
refrigerant (CO.sub.2) which is a natural refrigerant having a
small environmental load in consideration of flammability, toxicity
and the like. As oil which is a lubricant of the compressor 200,
there is used, for example, mineral oil, alkyl benzene oil, ether
oil, polyalkylene glycol (PAG), polyol ester (POE) or the like.
[0185] Since carbon dioxide is used as the refrigerant in the
refrigerating device 30 in this manner, the high pressure part of
the refrigerating cycle is brought into a supercritical state in
the refrigerating device 30 in a case where an outside air
temperature is not less than a critical temperature (about
+31.degree. C.) of carbon dioxide. Accordingly, the refrigerating
device 30 is operated as a transfer critical cycle.
[0186] There will be described an operation of the refrigerating
device 30 constituted as described above in the present embodiment
with reference to FIG. 9. The control unit 26 selectively allows
the refrigerating device 30 to perform the freezing operation
mainly allowing the second heat absorbing means 11 to function, the
freezing and refrigerating operation allowing the first heat
absorbing means 10 and the second heat absorbing means 11 to
perform freezing and refrigerating, and the refrigerating operation
mainly allowing the first heat absorbing means 10 to function.
[0187] First, the freezing operation will be described. It is to be
noted that this freezing operation is an operation allowing the
low-pressure heat sink 58 to function at a predetermined
temperature (e.g., around -26.degree. C.) and cool the freezing
room 22.
[0188] In the refrigerating device 30 of the present embodiment,
when the compressors 100, 200 are operated, the
intermediate-pressure refrigerant compressed and discharged from
the compressor 100 is further compressed and discharged from the
compressor 200. The refrigerant radiates heat in the radiator 2,
and is cooled. Thereafter, the refrigerant discharged from the
radiator 2 reaches the branch point 9A via the cooling heat
exchanger 32, and is branched at the point. A part of the
refrigerant circulates to the first heat absorbing means 10, and
the remaining refrigerant circulates to the second heat absorbing
means 11. It is to be noted that the refrigerant discharged from
the radiator 2 is super-cooled by the cooling heat exchanger 32 to
reach the branch point 9A in this state. Details will be described
later.
[0189] A pressure of the refrigerant circulated from the branch
point 9A to the first heat absorbing means 10 is reduced by the
intermediate-pressure expansion valve 65 to obtain a two-phase
mixture (gas/liquid mixed state) of gas and liquid. Moreover, this
refrigerant flows into the intermediate-pressure heat sink 57 in
the form of the two-phase mixture. However, in the present freezing
operation, the control unit 26 stops the fan 57F disposed in the
vicinity of the intermediate-pressure heat sink 57 to thereby
substantially stop the heat absorbing function of the heat sink 57.
Accordingly, the refrigerant discharged from the
intermediate-pressure expansion valve 65 hardly absorbs heat from
the surrounding area in the intermediate-pressure heat sink 57, and
reaches the cooling heat exchanger 32. In the cooling heat
exchanger 32, the refrigerant exchanges heat with the refrigerant
discharged from the radiator 2, and is warmed to form the gas
refrigerant. The refrigerant is introduced into the suction port of
the compressor 200. It is to be noted that the refrigerant
discharged from the compressor 200 and the radiator 2 is
super-cooled by the refrigerant discharged from the
intermediate-pressure heat sink 57 by means of the heat exchange in
the cooling heat exchanger 32.
[0190] On the other hand, the refrigerant circulated from the
branch point 9A to the second heat absorbing means 11 side
exchanges heat with the refrigerant circulated on the side of the
first heat absorbing means 10 as described above in the cooling
heat exchanger 32, and the super-cooled refrigerant reaches the
low-pressure expansion valve 66. The pressure of the refrigerant is
reduced to obtain the two-phase mixture of gas and liquid.
Moreover, since the fan 58F is operated by the control unit 26, the
refrigerant which has entered the low-pressure heat sink 58
evaporates in the heat sink 58 to absorb heat from the surrounding
area. Thereafter, in the heat exchanger 15, the refrigerant
exchanges heat with the refrigerant which is to enter the
low-pressure expansion valve 66, and is warmed. The refrigerant
returns to the suction port of the compressor 100. It is to be
noted that after the refrigerant is super-cooled in the cooling
heat exchanger 32 by means of the above-described heat exchange in
the heat exchanger 15, the refrigerant flowing into the
low-pressure expansion valve 66 via the branch point 9A is further
cooled.
[0191] Next, the freezing and refrigerating operation will be
described. It is to be noted that this freezing and refrigerating
operation is an operation allowing the intermediate-pressure heat
sink 57 and the low-pressure heat sink 58 at predetermined
temperatures (e.g., the intermediate-pressure heat sink 57 around
-5.degree. C., the low-pressure heat sink 58 around -26.degree. C.)
to cool the refrigerating room 21 and the freezing room 22.
[0192] Even in this case, when the compressors 100, 200 are
operated, the intermediate-pressure refrigerant compressed and
discharged from the compressor 100 is further compressed and
discharged from the compressor 200. The refrigerant radiates heat,
and is cooled in the radiator 2. Thereafter, the refrigerant
discharged from the radiator 2 reaches the branch point 9A via the
cooling heat exchanger 32, and is branched here. A part of the
refrigerant circulates in the first heat absorbing means 10, and
the remaining refrigerant circulates in the second heat absorbing
means 11. It is to be noted that the refrigerant discharged from
the radiator 2 is super-cooled in the cooling heat exchanger 32,
and reaches the branch point 9A in this state in the same manner as
in the above-described freezing operation. Details will be
described later.
[0193] The pressure of the refrigerant circulated from the branch
point 9A to the first heat absorbing means 10 is reduced by the
intermediate-pressure expansion valve 65 to obtain the two-phase
mixture of gas and liquid. Moreover, this refrigerant flows into
the intermediate-pressure heat sink 57 in the form of the two-phase
mixture. However, in the present freezing and refrigerating
operation, unlike the freezing operation, the control unit 26
operates the fan 57F disposed in the vicinity of the
intermediate-pressure heat sink 57 to thereby exert the heat
absorbing function of the intermediate-pressure heat sink 57.
Accordingly, the refrigerant discharged from the
intermediate-pressure expansion valve 65 evaporates in the
intermediate-pressure heat sink 57 to absorb heat from the
surrounding area, and reaches the cooling heat exchanger 32. In the
cooling heat exchanger 32, the refrigerant exchanges heat with the
refrigerant discharged from the radiator 2, and is warmed. The
refrigerant is introduced into the suction port of the compressor
200 in the form of the gas refrigerant.
[0194] It is to be noted that the refrigerant is discharged from
the compressor 200 and the radiator 2, and super-cooled by the
refrigerant discharged from the intermediate-pressure heat sink 57
by means of the heat exchange in the cooling heat exchanger 32.
However, in the present freezing and refrigerating operation,
unlike the freezing operation, since the heat absorbing function of
the intermediate-pressure heat sink 57 is exerted, a heat exchange
amount in the cooling heat exchanger 32 is smaller than that during
the freezing operation.
[0195] On the other hand, the refrigerant circulated from the
branch point 9A to the second heat absorbing means 11 side
exchanges heat with the refrigerant circulated on the side of the
first heat absorbing means 10 as described above in the cooling
heat exchanger 32, and the super-cooled refrigerant reaches the
low-pressure expansion valve 66. The pressure of the refrigerant is
reduced to obtain the two-phase mixture of gas and liquid.
Moreover, in this case, since the fan 58F is operated by the
control unit 26, the refrigerant which has entered the low-pressure
heat sink 58 evaporates in the heat sink 58 to absorb heat from the
surrounding area. Thereafter, the refrigerant passes through the
heat exchanger 15, and returns to the suction port of the
compressor 100.
[0196] Furthermore, the refrigerating operation will be described.
It is to be noted that this refrigerating operation is an operation
allowing the intermediate-pressure heat sink 57 to function at a
predetermined temperature (e.g., around -5.degree. C.) and cool the
refrigerating room 21. In the present refrigerating operation, the
control unit 26 closes the low-pressure expansion valve 66 to
interrupt refrigerant circulation from the branch point 9A to the
second heat absorbing means 11 side, and the refrigerant is
circulated on the first heat absorbing means 10 side only.
[0197] It is to be noted that in the present refrigerating
operation, since the second heat absorbing means 11 does not
function, energy is wasted even if the compressor 100 is operated.
When both of the compressors 100 and 200 are operated in the same
manner as in the freezing operation and the freezing and
refrigerating operation, a vacuum state is substantially brought
from the expansion valve 66 to the suction port of the compressor
100 via the low-pressure heat sink 58, because the low-pressure
expansion valve 66 is closed. Therefore, the compressor 100 sucks a
large amount of oil to cause oil compression, and the compressor
efficiency remarkably deteriorates.
[0198] To solve the problem, it is assumed that the compressor 100
is stopped by the control unit 26 in the refrigerating operation of
the present embodiment.
[0199] In this case, when the compressor 200 is operated, the
refrigerant compressed and discharged from the compressor 200
radiates heat, and is cooled in the radiator 2. Thereafter, the
refrigerant discharged from the radiator 2 passes through the
cooling heat exchanger 32 and the branch point 9A to circulate in
the first heat absorbing means 10.
[0200] The pressure of the refrigerant circulated from the branch
point 9A in the first heat absorbing means 10 is reduced by the
intermediate-pressure expansion valve 65 to obtain the two-phase
mixture (gas/liquid mixed state) of gas and liquid. Moreover, this
refrigerant flows into the intermediate-pressure heat sink 57 in
the form of the two-phase mixture, but in the present refrigerating
operation, the fan 57F disposed in the vicinity of the
intermediate-pressure heat sink 57 is operated by the control unit
26, thereby exerting the heat absorbing function of the heat sink
57.
[0201] Accordingly, the refrigerant discharged from the
intermediate-pressure expansion valve 65 evaporates in the
intermediate-pressure heat sink 57 to absorb heat from the
surrounding area. Thereafter, the refrigerant reaches the cooling
heat exchanger 32, and exchanges heat with the refrigerant
discharged from the radiator 2 in the cooling heat exchanger 32.
The refrigerant is thus warmed to form the gas refrigerant, and
introduced into the suction port of the compressor 200. It is to be
noted that the refrigerant discharged from the compressor 200 and
the radiator 2 is super-cooled by the refrigerant discharged from
the intermediate-pressure heat sink 57 by means of the heat
exchange in the cooling heat exchanger 32 as described above.
[0202] As described above, since the compressor 100 is stopped in
the present refrigerating operation, energy wasting can be
inhibited, and a high-efficiency refrigerating operation is
possible.
[0203] During all of the freezing operation, the freezing and
refrigerating operation, and the refrigerating operation, the
refrigerant circulates as described above to change its state,
thereby forming the refrigerating cycle.
[0204] Here, in the present embodiment, since the carbon dioxide
refrigerant is introduced into the refrigerant circuit, a dry
degree of the refrigerant entering the expansion valves 65, 66 is
excessively high in the refrigerant circuit for use in a
conventional chlorofluorocarbon-based refrigerant or an HC-based
refrigerant, that is, the refrigerant circuit in which the
expansion valves 65, 66 are disposed immediately after the radiator
2 even in a case where the outside air temperature is about
+22.degree. C. Therefore, a ratio of the gas refrigerant in the
refrigerant is high, and it is difficult to obtain a sufficient
cooling performance.
[0205] To solve the problem, in the refrigerating device 30, the
refrigerant pipe is branched from the branch point 9A, and one pipe
is provided with the first heat absorbing means 10 as well as the
cooling heat exchanger 32 to super-cool the refrigerant flowing
into the first and second heat absorbing means 10 and 11 in the
cooling heat exchanger 32. According to such constitution, a high
cooling effect can be obtained even in a case where the carbon
dioxide refrigerant having the above-described characteristics is
used. In this case, the refrigerant discharged from the side of the
first heat absorbing means 10 is introduced as the gas refrigerant
into the suction port of the compressor 200. Therefore, compression
efficiencies in the compressors 100, 200 can be improved, and a
refrigerating cycle efficiency of the refrigerating device 30 can
further be improved.
[0206] Moreover, during the freezing operation, unlike the freezing
and refrigerating operation, the control unit 26 stops the fan 57F
disposed in the vicinity of the intermediate-pressure heat sink 57
to increase a heat exchange amount in the cooling heat exchanger
32. According to this constitution, it is possible to increase a
super-cooling effect of the refrigerant flowing into the second
heat absorbing means 11, and it is possible to perform a
higher-efficiency freezing operation.
[0207] Next, there will be described an application example of the
refrigerating device 30 to a refrigerator in the present embodiment
with reference to FIG. 10. FIG. 10 shows a schematic constitution
diagram of the refrigerator provided with the refrigerating device
30.
[0208] A refrigerator 40 is constituted of: a refrigerating room 41
disposed in an upper stage; and a freezing room 42 disposed in a
lower stage. Moreover, refrigerator partition walls 61, 62 are
disposed in inner parts of the respective rooms 41, 42, and there
are arranged the intermediate-pressure heat sink 57, the
low-pressure heat sink 58, and the fans 63, 64 in air paths 44
defined by the refrigerator partition walls 61, 62. Moreover, the
freezing room 42 is provided with a temperature sensor 42T, and the
refrigerating room 41 is provided with a temperature sensor
41T.
[0209] Furthermore, during each above-described operation, that is,
during the freezing operation, the fan 64 is operated. During the
freezing and refrigerating operation, the fans 63, 64 are operated.
Further during the refrigerating operation, the fan 63 is operated.
This can cool the respective rooms 41, 42.
[0210] In the present embodiment, since the refrigerator 40 is
provided with the above-described constitution, a high cooling
performance and a high-efficiency operation are possible even in a
case where carbon dioxide is used in the refrigerant. During the
refrigerating operation, since the compressor 100 is stopped, the
refrigerating cycle efficiency can further be improved.
Embodiment 5
[0211] Next, another embodiment of the present invention will be
described with reference to FIG. 11. FIG. 11 shows a refrigerant
circuit diagram of a refrigerating device 50 in the present
embodiment. In the present embodiment, the refrigerating device 50
is different from the refrigerating device 30 in that one
compressor is disposed and this compressor 1 is constituted of a
multistage compressor.
[0212] The compressor 1 is a two-stage compressor including a
first-stage compressing section 1A and a second-stage compressing
section 1B in a sealed container. An intermediate cooling unit 1C
is disposed in a refrigerant pipe of the first-stage compressing
section 1A on a discharge side. That is, in the present embodiment,
the first-stage compressing section 1A performs a function of a
compressor 100 as a front-stage compression element of Embodiment
4, and the second-stage compressing section 1B performs a function
of a compressor 200 as a rear-stage compression element.
[0213] Here, the compressor 1 of the present embodiment will be
described with reference to FIG. 12. FIG. 12 is a schematic
sectional view of the compressor 1.
[0214] The compressor 1 is a high inner pressure type two-stage
compression system rotary compressor. The compressor 1 is provided
with a sealed container 112 whose upper and lower ends are both
sealed and which substantially has a vertically long cylindrical
shape. A bottom portion of this sealed container 112 is constituted
as an oil reservoir. The sealed container 112 includes: an
electromotive element 114; and a rotary compressing section 118
constituted of the first compressing section 1A and the second
compressing section 1B driven via a rotation shaft 116 of the
electromotive element 114, and an outer face of a bottom of the
container is provided with leg portions 210 for fixing the
compressor 1 to, for example, a refrigerator housing (not
shown).
[0215] The sealed container 112 is constituted of: a container main
body 112A which stores the electromotive element 114 and the rotary
compressing section 118; and a substantially bowl-shaped end cap
(lid member) 112B which closes an end portion of this container
main body 112A on the side of the electromotive element 114. A
circular attachment hole 112D is formed in this end cap 112B, and a
terminal 120 (wiring line is omitted) for supplying power to the
electromotive element 114 is attached to the attachment hole
112D.
[0216] The electromotive element 114 is constituted of: a stator
122 annularly attached along an inner peripheral face of the sealed
container 112; and a rotor 124 inserted in the electromotive
element and internally disposed at a slight interval from the inner
peripheral face of this stator 122. This rotor 124 is fixed to the
rotation shaft 116 which passes through the center and which
extends in an axial center direction of the sealed container 112.
Here, the stator 122 has: a laminate (not shown) constituted of
laminated donut-shaped electromagnetic steel plates; and a stator
coil 128 wound around a tooth portion of this laminate by a direct
winding method. Moreover, the rotor 124 is formed of a laminate of
electromagnetic steel plates in the same manner as in the stator
122. The rotor is formed by inserting a permanent magnet in this
laminate.
[0217] Moreover, in the rotation shaft 116, an oil passage 182
extends through the axial center of the shaft in a perpendicular
direction. One end of this oil passage 182 on the side of the
rotary compressing section 118 opens to the oil reservoir which is
the bottom portion of the sealed container 112. The other end of
the passage on the side of the electromotive element 114 opens on
the side of the end cap 112B. It is to be noted that this oil
passage 182 communicates with sliding portions of the respective
stage compressing sections 1A, 1B, and is constituted so that oil
can be supplied to the compressing sections 1A, 1B.
[0218] The first-stage compressing section 1A and the second-stage
compressing section 1B of the rotary compressing section 118 are
constituted of first and second cylinders 138, 140, and an
intermediate partition plate 136 is sandwiched between these
cylinders 138 and 140. The respective stage compressing sections
1A, 1B are constituted of: first and second rollers 146, 148 which
are fitted into the first and second cylinders 138, 140 disposed on
opposite sides (upper and lower sides in FIG. 12) of the
intermediate partition plate 136 and first and second eccentric
sections 142, 144 disposed on the rotation shaft 116 and having a
phase difference of 180 degrees and which eccentrically rotate in
the first and second cylinders 138, 140; first and second vanes
150, 152 which abut on these rollers 146, 148, respectively, to
define low-pressure and high-pressure chamber sides in the
cylinders 138, 140; and support members 154, 156 which close an
open face of the cylinder 140 on the side of the electromotive
element 114 and an open face of the cylinder 138 on the side
opposite to the electromotive element 114 and which also function
as bearings of the rotation shaft 116.
[0219] In the second-stage compressing section 1B, in the outside
of the second vane 152 (right side in FIG. 12), there is disposed a
spring 176 which abuts on an outer end portion of the second vane
152 to urge the second vane 152 toward the roller 148. Furthermore,
a plug 223 made of a metal is disposed on the sealed container 112
side of the spring 176, and prevents the spring 176 from being
detached. A back pressure chamber (not shown) is constituted in the
second vane 152, and a pressure on the side of the high-pressure
chamber of the cylinder 140 is applied as a back pressure to this
back pressure chamber.
[0220] On the other hand, in the first-stage compressing section
1A, a magnet 151 constituted of, for example, a permanent magnet is
attached to an outer end portion of the vane 150 on the side
opposite to the roller 146. A plug 222 is disposed so as to face
the plug 222 disposed in the second-stage compressing section 1B,
and an electromagnet 175 is disposed on the magnet 151 side of the
plug 222.
[0221] Moreover, the support members 154, 156 are provided with
discharge noise absorbing chambers 162, 164 formed by partially
depressing the members and closing the depressed portions with a
baffle plate 200 and a cover 168, respectively, as described later.
That is, the discharge noise absorbing chamber 162 is formed by
closing the depressed portion of the support member 154 with the
baffle plate 200, and the discharge noise absorbing chamber 164 is
formed by closing the depressed portion of the support member 156
with the cover 168.
[0222] The discharge noise absorbing chamber 162 communicates with
the sealed container 112 via a discharge pipeline 221 extending
through the baffle plate 200 to open on the side of the
electromotive element 114. The high-pressure refrigerant gas
compressed in the second-stage compressing section 1B is discharged
toward the electromotive element 114 in the sealed container 112
via the discharge pipeline 221. In this case, the refrigerant gas
is mixed with the oil supplied to the second-stage compressing
section 1B, but this oil is also discharged toward the
electromotive element 114 in the sealed container 112. Moreover,
the oil mixed in the refrigerant gas is separated from the
refrigerant gas, and stored in the oil reservoir which is the
bottom portion of the sealed container 112.
[0223] Moreover, the sealed container 112 is connected to: a
refrigerant introducing tube 194 for introducing the refrigerant
gas into the first-stage compressing section 1A; an intermediate
refrigerant discharge tube 192 which discharges, to the outside of
the sealed container 112, the refrigerant gas compressed in the
first-stage compressing section 1A to obtain an intermediate
pressure; an intermediate refrigerant introducing tube 193 which
introduces the intermediate-pressure refrigerant discharged from
the intermediate refrigerant discharge tube 192 into the
second-stage compressing section 1B via the intermediate cooling
unit 1C as described above; and a refrigerant discharge tube 196
for discharging, from the compressor 1, the refrigerant gas
compressed in the second-stage compressing section 1B under the
high pressure and discharged into the sealed container 112 via the
discharge pipeline 221 as described above. The connected tubes are
inserted in the sealed container.
[0224] Even in the present embodiment, there are selectively
performed a freezing operation, a freezing and refrigerating
operation, and a refrigerating operation in the same manner as in
Embodiment 4.
[0225] First, the freezing operation will be described. When the
compressor 1 is operated during the freezing operation, the
intermediate-pressure refrigerant compressed and discharged from
the first-stage compressing section 1A is further compressed and
discharged from the second-stage compressing section 1B to radiate
heat in the radiator 2, and the refrigerant is cooled. Thereafter,
in the refrigerating device 50, there is formed a refrigerating
cycle similar to that during the freezing operation of Embodiment
4, and the freezing room 22 is cooled.
[0226] Next, the freezing and refrigerating operation will be
described. Even during the freezing and refrigerating operation,
when the compressor 1 is operated in the same manner as in the
freezing operation, the intermediate-pressure refrigerant
compressed and discharged from the first-stage compressing section
1A is further compressed and discharged from the second-stage
compressing section 1B to radiate heat in the radiator 2, and the
refrigerant is cooled. Thereafter, in the refrigerating device 50,
there is formed a refrigerating cycle similar to that during the
freezing and refrigerating operation of Embodiment 4, and the
respective rooms 21, 22 are cooled.
[0227] Furthermore, the refrigerating operation will be described.
In Embodiment 4, the control unit 26 stops the compressor 100 as
the front-stage compression element in two compressors 100, 200 in
order to inhibit energy wasting and deterioration of a compressor
efficiency during the refrigerating operation. However, in the
compressor 1 of the present embodiment, the first-stage compressing
section 1A and the second-stage compressing section 1B are
connected to each other via the same rotation shaft 116. Therefore,
it is difficult to stop the only first-stage compressing section 1A
which is the front-stage compression element during the
refrigerating operation.
[0228] To solve the problem, in order to make possible a
single-stage operation during the refrigerating operation, that is,
the refrigerant compressing operation by the second-stage
compressing section 1B only, the magnet 151 is attached to the
outer end face of the vane 150 on the side opposite to the roller
146, and the electromagnet 175 is disposed on the side of the
sealed container 112 so as to face the magnet. This constitution
realizes the single-stage operation as described above.
[0229] Here, there will be described the single-stage operation of
the compressor 1 in the present embodiment with reference to FIGS.
13 and 14.
[0230] FIGS. 13 and 14 are schematic diagrams showing a compression
mechanism constituted of the vane 150 and the roller 146 in the
first-stage compressing section 1A. It is to be noted that FIG. 13
shows the first-stage compressing section 1A during a multi-stage
operation, that is, during the freezing operation and the freezing
and refrigerating operation, and FIG. 14 shows the first-stage
compressing section 1A during the single-stage operation, that is,
the refrigerating operation.
[0231] In FIG. 13, the vane 150 abuts on the roller 146 to define a
compression chamber P and a suction chamber V in a crescent-shaped
space formed between the roller 146 and the cylinder 138.
[0232] As described above, the vane 150 is attached to the outer
end face of the vane 150 on the side opposite to the roller 146.
Moreover, when the compressor 1 is operated in multiple stages as
shown in FIG. 13, the control unit 26 energizes the electromagnet
175 in such a manner that the electromagnet reacts against the
magnet 151. Accordingly, the vane 150 is pressed onto the roller
146 owing to repulsive forces of the magnet 151 and the
electromagnet 175. In consequence, the first-stage compressing
section 1A functions as the front-stage compression element, and
the compressor 1 is operated in the multiple stages.
[0233] On the other hand, during the single-stage operation, as
shown in FIG. 14, the control unit 26 energizes the electromagnet
175 in such a manner that the electromagnet attracts the magnet
151. Accordingly, the vane 150 is attracted by the magnet 151 as
well as the electromagnet 175, and the vane 150 does not abut on
the roller 146. In consequence, the compression chamber P and the
suction chamber V shown in FIG. 13 are not formed, the first-stage
compressing section 1A does not function as the front-stage
compression element, and the compressor 1 is operated in the single
stage.
[0234] As described above in detail, in the present embodiment, the
refrigerating device 50 is constituted so as to dispose the magnet
151 and the electromagnet 175 in the first-stage compressing
section 1A of the compressor 1. According to this constitution,
even in a case where the compressor 1 as the multistage compressor
is used, it is possible to stop the compressing operation of the
first-stage compressing section 1A which is the front-stage
compression element during the refrigerating operation, energy
wasting can be inhibited, and a high-efficiency refrigerating
operation is possible.
[0235] Moreover, in the present embodiment, unlike Embodiment 4,
the compressor can be constituted of one unit, and it is possible
to save space of the refrigerating device 50.
[0236] It is to be noted that needless to say, the refrigerating
device 50 is also applicable to a refrigerator in the same manner
as in the refrigerating device 30 of Embodiment 4.
Embodiment 6
[0237] Next, there will be described still another embodiment of
the present invention with reference to FIG. 15. FIG. 15 shows a
refrigerant circuit diagram of a refrigerating device 70 in the
present embodiment. The refrigerating device 70 of the present
embodiment is different from the refrigerating device 50 of
Embodiment 5 in that a compressor 101 is disposed instead of the
compressor 1.
[0238] The compressor 101 will be described with reference to FIGS.
16 and 17. FIGS. 16 and 17 are schematic sectional views of the
compressor 101. It is to be noted that FIG. 16 shows the compressor
101 during the multistage operation, that is, the freezing
operation and the freezing and refrigerating operation, and FIG. 17
shows the compressor 101 during the single-stage operation, that
is, the refrigerating operation.
[0239] The compressor 101 is different from the compressor 1 of
Embodiment 5 in that: a magnet 151 and an electromagnet 175 are not
disposed in a first-stage compressing section 1A; a vane 150 abuts
on a roller 146 via a spring 174 in the same manner as in a
second-stage compressing section 1B; a rotation shaft 116 is
divided into two between a first eccentric section 142 and a second
eccentric section 144; and two divided rotation shafts 116, that
is, a first rotation shaft 116A and a second rotation shaft 116B
are connected to each other via a gear portion 117 disposed between
the first eccentric section 142 and the second eccentric section
144.
[0240] It is to be noted that a magnet 119 is attached to an end
portion of the second rotation shaft 116B on the side opposite to
the gear portion 117, and an electromagnet 177 is disposed in the
vicinity of a bottom portion of a sealed container 112 facing this
magnet 119.
[0241] Moreover, during the freezing operation and the freezing and
refrigerating operation, a control unit 26 executes a control so
that the electromagnet 177 is not energized or the electromagnet
177 is energized so as to react against the magnet 119.
Accordingly, as shown in FIG. 16, the first and second rotation
shafts 116A and 116B are connected to each other via the gear
portion 117. When the compressor 101 is operated, the rotation
shafts 116A, 116B rotate together, and the compressor 101 is
operated in multiple stages.
[0242] On the other hand, when the control unit 26 energizes the
electromagnet 177 so as to attract the magnet 119 during the
refrigerating operation. the second rotation shaft 116B is
attracted together with the magnet 119 by the electromagnet 177,
and the first rotation shaft 116A is detached from the second
rotation shaft 116B via the gear portion 117. Accordingly, in this
case, even when the compressor 101 is operated, a rotary force from
an electromotive element 114 is not transmitted to the second
rotation shaft 116B, and the compressor 101 is operated in a single
stage of a second-stage compressing section 101B only.
[0243] As described above in detail, in the refrigerating device 70
of the present embodiment, the rotation shaft of the compressor 101
is constituted of the first and second rotation shafts 116A, 116B,
and there are arranged the gear portion 117, the magnet 119, and
the electromagnet 177 which function as a clutch mechanism.
Accordingly, even when the compressor 101 as the multistage
compressor is used, it is possible to stop the compressing
operation of a first-stage compressing section 1A which is a
front-stage compression element, energy saving can be inhibited,
and a high-efficiency refrigerating operation is possible.
[0244] Moreover, in the present embodiment, the compressor can be
constituted of one unit in the same manner as in Embodiment 5, and
space of the refrigerating device 70 can be saved.
[0245] It is to be noted that needless to say, even the
refrigerating device 70 is applicable to a refrigerator in the same
manner as in the above-described embodiments.
[0246] The present invention has been described above in accordance
with the embodiment, but the present invention is not limited to
the embodiment, and various modifications are possible. For
example, a carbon dioxide refrigerant is introduced into a
refrigerant circuit in the above-described embodiment, but the
present invention is not limited to the embodiment, and is
applicable to another embodiment in which a
chlorofluorocarbon-based refrigerant is introduced.
[0247] Moreover, the expansion valves 65 and 66 of the
above-described embodiments may be changed to capillary tubes if
necessary.
Embodiment 7
[0248] Next, Embodiment 7 of the present invention will be
described in detail with reference to the drawings. FIG. 18 shows a
refrigerant circuit diagram of a refrigerating device in one
embodiment of the present invention. In the present embodiment,
there are provided a refrigerating device capable of inhibiting a
drying agent from being crushed even in a case where a refrigerant
such as carbon dioxide is used, a refrigerator, and a gas-liquid
separator disposed in a refrigerating cycle. The present embodiment
will be described hereinafter in detail with reference to the
drawings.
[0249] A refrigerating device 30 includes: a compressor 1; a
radiator 2 connected to a discharge side of this compressor 1; a
third capillary tube 31 connected to an outlet side of this
radiator 2; a gas-liquid separator 4 connected to the outlet side
of this third capillary tube 31; heat absorbing means 8 in which a
liquid refrigerant separated by this gas-liquid separator
circulates; and a first heat exchanger 15 constituted so as to
exchange heat between a refrigerant discharged from the heat
absorbing means 8 and a refrigerant in the vicinity of the third
capillary tube 31. A refrigerant introducing tube 6 through which a
gas refrigerant separated by the gas-liquid separator 4 flows is
connected to an intermediate-pressure portion of the compressor 1,
and an outlet side of the first heat exchanger 15 is connected to a
suction port of the compressor 1 to constitute a refrigerating
cycle.
[0250] Moreover, a check valve 7 is disposed in the refrigerant
introducing tube 6 between the gas-liquid separator 4 and the
intermediate-pressure portion of the compressor 1, and a check
valve 53 is disposed between the first heat exchanger 15 and the
suction port of the compressor 1.
[0251] The heat absorbing means 8 includes: a three-way valve 91; a
first capillary tube 12; a second capillary tube 13 which is
disposed in parallel with this first capillary tube 12 and whose
resistance value is larger than that of the first capillary tube
12; and a heat sink 14 disposed after a junction 9A at which
refrigerant pipes from these first and second capillary tubes 12,
13 are combined. This heat absorbing means 8 selectively functions
in different temperature zones. When the three-way valve 91 is
switched to pass the liquid refrigerant discharged from the
gas-liquid separator 4 through the side of the first capillary tube
12, a flow rate of the refrigerant flowing through the heat sink 14
increases, and a refrigerating operation is performed.
[0252] On the other hand, when the three-way valve 91 is switched
to pass the refrigerant on the side of the second capillary tube
13, the flow rate of the refrigerant flowing through the heat sink
14 lowers, and a freezing operation is performed.
[0253] It is to be noted that the refrigerating operation and the
freezing operation may be switched by a method of changing the
number of revolutions of the compressor 1 to control the flow rate
of the refrigerant flowing through the heat sink 14 in addition to
the method of switching the first and second capillary tubes. 12,
13 as described above. These methods may be combined to realize the
switching of the operation.
[0254] Furthermore, the refrigerating device 30 is provided with
selection means 23 for feeding cold air generated by the heat sink
14 by means of a fan (not shown) to selectively guide cold air to a
plurality of rooms (refrigerating room 21, freezing room 22) which
are controlled in different temperature zones.
[0255] This selection means 23 includes an air feed duct 24 and a
changeover damper 25, a duct 57A is disposed between this
changeover damper 25 and the refrigerating room 21, and a duct 58A
is disposed between the changeover damper and the freezing room 22.
The changeover damper 25 is connected to a control unit 26. This
control unit 26 is connected to the above-described three-way valve
91. For example, during the freezing operation, the three-way valve
91 is switched to a second capillary tube 13 side, the changeover
damper 25 is switched so as to allow air to flow through the duct
58A, and cold air is introduced into the freezing room 22. During
the refrigerating operation, the three-way valve 91 is switched to
a first capillary tube 12 side, the changeover damper 25 is
switched so as to allow cold air to flow through the duct 57A, and
cold air is introduced into the refrigerating room 21.
[0256] The compressor 1 is a two-stage compressor including a
first-stage compressing section 1A and a second-stage compressing
section 1B in a sealed container. An intermediate cooling unit 1C
is disposed in a refrigerant pipe connecting the first-stage
compressing section 1A to the second-stage compressing section 1B
outside the sealed container.
[0257] Moreover, as described above, the refrigerant introducing
tube 6 is connected in such a manner that the gas refrigerant
discharged from the gas-liquid separator 4 can be introduced into
the intermediate-pressure portion of the compressor 1, that is,
between the intermediate cooling unit 1C and the second-stage
compressing section 1B. It is to be noted that the separated gas
refrigerant is introduced into the intermediate-pressure portion of
the compressor 1 owing to a difference pressure in the refrigerant
introducing tube 6 as shown by a broken-line arrow. It is to be
noted that this compressor 1 is not limited to the two-stage
compressor. For example, in a single-stage compressor, the
refrigerant introducing tube 6 may be returned to the
intermediate-pressure portion of the single-stage compressor.
Alternatively, a plurality of compressors may be connected.
[0258] Here, the gas-liquid separator 4 will be described with
reference to FIG. 19. FIG. 19 is a schematic sectional view of the
gas-liquid separator 4.
[0259] The gas-liquid separator 4 includes: a container 80
constituted of a substantially columnar hollow member; a first
adsorbing section 81A; support members 81B, 81C which are disposed
under and on the first adsorbing section 81A and which fix the
first adsorbing section 81A in the container 80; a second adsorbing
section 82A; and support members 82B, 82C which are disposed under
and on this second adsorbing section 82A and which fix the
adsorbing section 82A in the container 80. Moreover, the side face
of the container 80 is connected to a refrigerant pipe 4A for
introducing the refrigerant discharged from the radiator 2 and
having a gas and liquid mixed state, and the top of the container
is connected to the refrigerant introducing tube 6 via which there
flows the gas refrigerant separated by the gas-liquid separator 4
and which is connected to the intermediate-pressure portion of the
compressor 1. The bottom of the container is connected to a
refrigerant pipe 4B via which there flows the liquid refrigerant
separated by the gas-liquid separator 4 and which is connected to
the three-way valve 91. It is to be noted that the separated liquid
refrigerant is stored from a lower portion of the container 80
toward the refrigerant pipe 4B.
[0260] The first and second adsorbing sections 81A, 82A adsorb and
remove a water content mixed in the refrigerant, and are filled
with a so-called drying agent such as activated alumina, zeolite,
or molecular sieve. The support members 81B, 81C, 82B, and 82C may
be constituted of any material that can prevent outflow from the
adsorbing sections 81A, 82A and that can allow the refrigerant to
circulate. For example, a metal mesh, a resin mesh or the like is
used.
[0261] Furthermore, in the refrigerating device 30 of the present
embodiment, as the refrigerant, there is used a carbon dioxide
refrigerant (CO.sub.2) which is a natural refrigerant having a
small environmental load in consideration of flammability, toxicity
and the like. As oil which is a lubricant of the compressor 1,
there is used, for example, mineral oil, alkyl benzene oil, ether
oil, ester oil, polyalkylene glycol (PAG), polyol ester (POE) or
the like.
[0262] Since carbon dioxide is used as the refrigerant in the
refrigerating device 30 in this manner, a high pressure part of the
refrigerating cycle is brought into a supercritical state in a case
where an outside air temperature is not less than a critical
temperature (about +31.degree. C.) of carbon dioxide. Accordingly,
the refrigerating device 30 is operated as a transfer critical
cycle.
[0263] It is to be noted that in the present embodiment, in FIG.
18, the high pressure part of the refrigerating cycle of the
refrigerating device 30 is operated which corresponds to a part
from the discharge side of the second-stage compressing section 1B
to an inlet to the third capillary tube 31 via the radiator 2. An
intermediate-pressure part of the refrigerating cycle of the
refrigerating device 30 is operated which corresponds to a part
from the discharge side of the first-stage compressing section 1A
to the suction port of the second-stage compressing section 1B via
the intermediate cooling unit 1C, and the outlet of the third
capillary tube 31 to the suction port of the second-stage
compressing section 1B via the gas-liquid separator 4 and to the
three-way valve 91. Moreover, a low-pressure part of the
refrigerating cycle of the refrigerating device 30 is operated
which corresponds to a part from the outlet of the three-way valve
91 to the suction port of the first-stage compressing section 1A
via the heat absorbing means 8 and the first heat exchanger 15.
[0264] There will be described an operation of the refrigerating
device 30 of the present embodiment constituted as described above
with reference to FIGS. 18 and 19. In the refrigerating device 30,
there are selected as required a freezing operation mainly using
the second capillary tube 13, and a refrigerating operation mainly
using the first capillary tube 12.
[0265] First, the freezing operation will be described. It is to be
noted that this freezing operation is an operation allowing the
heat sink 14 to function at a predetermined temperature (e.g.,
around -26.degree. C.) and cool the freezing room 22.
[0266] In the present embodiment, when the compressor 1 is
operated, the refrigerant discharged from the compressor 1 radiates
heat in the radiator 2, and is cooled. Thereafter, the refrigerant
discharged from the radiator 2 reaches the third capillary tube 31.
Here, a pressure of the refrigerant is reduced to obtain a gas and
liquid mixed state (two-phase mixture of gas and liquid). The
refrigerant is introduced from the refrigerant pipe 4A of the
gas-liquid separator 4 into the container 80 of the gas-liquid
separator 4. The refrigerant in this container 80 is separated into
a gas refrigerant and a liquid refrigerant. As shown by a
broken-line arrow in FIG. 19, the gas refrigerant passes through
the second adsorbing section 82A, circulates in the check valve 7,
and passes through the check valve 7. Thereafter, the refrigerant
is introduced into the intermediate-pressure portion of the
compressor 1. On the other hand, the liquid refrigerant separated
in the gas-liquid separator 4 passes through the first adsorbing
section 81A, flows through the refrigerant pipe 4B, and reaches the
heat absorbing means 8 as shown by a one-dot chain-line arrow in
FIG. 19.
[0267] It is to be noted that the refrigerating device 30 is
constituted so as to perform two-stage expansion by means of the
third capillary tube 31 and the first or second capillary tube 12,
13. Therefore, the intermediate-pressure part of the present
refrigerating cycle includes: a part between the outlet side of the
third capillary tube 31 and the inlet side of the first and second
capillary tubes 12, 13; a part between the discharge side of the
first-stage compressing section 1A of the compressor 1 and the
suction side of the second-stage compressing section 1B; and a part
in the refrigerant introducing tube 6.
[0268] Moreover, the liquid refrigerant is circulated on the second
capillary tube 13 side by means of the three-way valve 91 of the
heat absorbing means 8. The liquid refrigerant evaporates in the
heat sink 14 to absorb heat from a surrounding area. Thereafter,
the refrigerant exchanges heat with the refrigerant in the vicinity
of the third capillary tube 31 in the first heat exchanger 15, and
the refrigerant is warmed and returned to the suction port of the
compressor 1. It is to be noted that since the changeover damper 25
is switched so as to circulate cold air on the duct 58A side by the
control unit 26 during the freezing operation, the freezing room 22
is cooled.
[0269] Next, the refrigerating operation will be described. It is
to be noted that this refrigerating operation is an operation which
allows the heat sink 14 to function at a temperature (e.g., around
-5.degree. C.) higher than that during the freezing operation and
which cools the refrigerating room 21 in a concentrated manner.
[0270] During the refrigerating operation, a selected temperature
zone in the heat absorbing means 8 differs from that during the
freezing operation. That is, after the liquid refrigerant
discharged from the gas-liquid separator 4 is circulated on the
first capillary tube 12 side by means of the three-way valve 91 of
the heat absorbing means 8, the refrigerant evaporates in the heat
sink 14 to absorb heat from the surrounding area. It is to be noted
that since the changeover damper 25 is switched so as to circulate
cold air on the duct 57A side by the control unit 26 during the
present refrigerating operation, the refrigerating room 21 is
cooled. In the refrigerating device 30 of the present embodiment,
the above-described refrigerating cycle is formed during both of
the freezing operation and the refrigerating operation.
[0271] It is to be noted that in the refrigerating device 30, the
gas refrigerant separated by the gas-liquid separator 4 cannot be
used in the cooling, even if the refrigerant is circulated in the
heat absorbing means 8. When the refrigerant is returned to the
suction port of the first-stage compressing section 1A, a
compression efficiency in the compressor 1 is lowered.
[0272] To solve the problem, in the present embodiment, the gas
refrigerant separated by the gas-liquid separator 4 is introduced
into the intermediate-pressure portion of the compressor 1, that
is, between the intermediate cooling unit 1C and the second-stage
compressing section 1B. Therefore, a compression efficiency in the
compressor 1 can be improved. Especially in the present embodiment,
since the carbon dioxide refrigerant is introduced in the
refrigerant circuit, a gas content is larger than a content of a
chlorofluorocarbon-based refrigerant or the like in a ratio of the
gas and the liquid separated by the gas-liquid separator 4. Since
the large gas content is introduced into the intermediate-pressure
portion of the compressor 1, the efficiency can further be
enhanced.
[0273] Furthermore, in the present embodiment, there are arranged
the first and second adsorbing sections 81A, 82A as driers in the
container 80 of the gas-liquid separator 4 as described above.
Accordingly, the gas-liquid separator 4 is structured as a drier
integral type. Therefore, unlike a conventional art, without
separately disposing any drier in the refrigerating cycle, the
water content in the refrigerant can be adsorbed and removed in the
gas-liquid separator 4, and the inside of the pipe can be prevented
from being frozen. The number of components can be reduced, and
costs can be reduced.
[0274] Moreover, carbon dioxide is used as the refrigerant in the
refrigerating device 30. When carbon dioxide is used as the
refrigerant in this manner, the high-pressure side of the
refrigerating cycle, that is, a part between the discharge side of
the compressor 1 and the inlet side of the third capillary tube 31
has a much higher pressure as compared with the use of a
hydrofluorocarbon (HFC) refrigerant or a hydrocarbon (HC)
refrigerant as in a conventional art. In a case where the drier is
disposed in this high-pressure part, a pressure resistant
performance is demanded, but in the present embodiment, since the
drier integral type gas-liquid separator 4 is disposed in the
intermediate-pressure part, the pressure resistant performance of
the container 80 can be inhibited, and the drying agent (adsorbing
section) can be prevented from being crushed owing to the
high-temperature high-pressure refrigerant. Moreover, since the gas
refrigerant or the liquid refrigerant passes through the first and
second adsorbing sections 81A, 82A of the gas-liquid separator 4 in
the refrigerating device 30, a liquid face of a liquid reservoir
portion in the gas-liquid separator 4 is easily stabilized by a
rectifying function in these adsorbing sections.
[0275] It is to be noted that the gas-liquid separator 4 has been
described above as a gas-liquid separator with reference to FIG.
19, but structures shown in FIGS. 20 and 21 are applicable.
[0276] FIG. 20 is a schematic sectional view of a gas-liquid
separator 4-2 having another structure. This gas-liquid separator
is different from the gas-liquid separator 4 in that the second
adsorbing section 82A and the support members 82B, 82C are not
disposed. FIG. 21 is a schematic sectional view of a gas-liquid
separator 4-3 having still another structure. This gas-liquid
separator is different from the gas-liquid separator 4 in that the
first adsorbing section 81A and the support members 81B, 81C are
not disposed. In these gas-liquid separators 4-2, 4-3, cost
reduction is possible as compared with the gas-liquid separator 4,
and needless to say, the separators become valid depending on use
states and use conditions.
[0277] Next, there will be described an example in which the
refrigerating device 30 of the present embodiment is applied to a
refrigerator with reference to FIG. 22. FIG. 22 shows a schematic
constitution diagram of the refrigerator provided with the
refrigerating device 30.
[0278] This refrigerator 40 is constituted of: a refrigerating room
41 disposed in an upper stage; and a freezing room 42 disposed in a
lower stage. Moreover, a refrigerator partition wall 43 is disposed
in an inner part of the respective room 42, and the heat sink 14 is
disposed in an air path 44 defined by the refrigerator partition
wall 43. A first changeover damper 45 is disposed in an inlet A to
the air path 44, and the first changeover damper 45 is switched
between a position (broken-line position) to close the inlet A of
the air paths 44 and an open position (solid-line position). A
rear-side air path 46 is formed in a rear wall 47 of the
refrigerator 40. When the first changeover damper 45 is switched to
the broken-line position, the inlet A of the air path 44
communicates with the refrigerating room 41 via the rear-side air
path 46. An outlet B of the air path 44 is provided with a fan 48
and a second changeover damper 49. The second changeover damper 49
is switched between a position (broken-line position) to close the
outlet B of the air paths 44 and an open position (solid-line
position). In this solid-line position, the second changeover
damper 49 closes an opening 51 of an intermediate partition wall
50.
[0279] According to the above-described constitution, during the
freezing operation, the first changeover damper 45 is switched to
the position (solid-line position) to open the inlet A to the air
path 44, and the second changeover damper 49 is switched to the
position (solid-line position) to open the outlet B of the air path
44, so that air is circulated in the freezing room 42, and cooled
by the heat sink 14. During the refrigerating operation, the first
changeover damper 45 is switched to the position (broken-line
position) to close the inlet A to the air path 44, and the second
changeover damper 49 is switched to the position (broken-line
position) to close the outlet B of the air path 44, so that air is
circulated in the refrigerating room 41 via the rear-side air path
46, and cooled by the heat sink 14.
Embodiment 8
[0280] Next, another embodiment of the present invention will be
described with reference to FIG. 23. FIG. 23 shows a refrigerant
circuit diagram of a refrigerating device 50 in this case. In the
present embodiment, components denoted with the same reference
numerals as those of Embodiment 7 produce the same or similar
functions or effects. The present embodiment is different from
Embodiment 7 in that an outlet side of a three-way valve 91 is
provided with first heat absorbing means 10 and second heat
absorbing means 11 disposed in parallel with the first heat
absorbing means instead of heat absorbing means 8.
[0281] The first heat absorbing means 10 includes: a first
capillary tube 12; and a first heat sink 57 disposed in series to
this first capillary tube 12. The second heat absorbing means 11
includes: a second capillary tube 13; a second heat sink 58
disposed in series to the second capillary tube 13; and a check
valve 52. Moreover, after refrigerant pipes on an outlet side of
the first and second heat absorbing means 10, 11 are combined at a
junction 9B, the pipe is connected to a suction port of a
compressor 1 via a first heat exchanger 15 and a check valve 53 in
the same manner as in the refrigerating device 30 of Embodiment 7.
The first heat absorbing means 10 and the second heat absorbing
means 11 function in mutually selectively different temperature
zones.
[0282] As described above, since the refrigerating device 50 of the
present embodiment is provided with the first and second heat
absorbing means 10, 11, a refrigerating room 21 and a freezing room
22 can be selectively cooled via ducts 57A, 58A in heat sinks 57,
58. The heat sink suitable for the temperature is usable in the
freezing operation and the refrigerating operation having different
temperature zones, and improvements of operation efficiencies of
the operations can be expected.
[0283] Next, there will be described an example in which the
refrigerating device 50 of the present embodiment is applied to a
refrigerator with reference to FIG. 24.
[0284] FIG. 24 shows a schematic constitution diagram of the
refrigerator provided with the refrigerating device 50 of the
present embodiment. This refrigerator 40 is constituted of: a
refrigerating room 41 disposed in an upper stage; and a freezing
room 42 disposed in a lower stage. Moreover, refrigerator partition
walls 61, 62 are disposed in inner parts of the respective rooms
41, 42, and the heat sinks 57, 58 and fans 63, 64 are disposed in
air paths 44 defined by the refrigerator partition walls 61, 62. In
the present constitution, when a thermostat turns on or off in the
refrigerating operation and the freezing operation, the first heat
absorbing means 10 and the second heat absorbing means 11 are
switched to allow the refrigerant to flow through one of the heat
sinks 57, 58, and the corresponding fan 63 or 64 is driven. When
the refrigerant flows through the heat sink 57, cold air is
supplied to the refrigerating room 41. When the refrigerant flows
through the heat sink 58, cold air is supplied to the freezing room
42.
[0285] As described above, since the refrigerator 40 of the present
embodiment is provided with the above-described refrigerating
device 50, a high cooling performance and a high-efficiency
operation are possible.
Embodiment 9
[0286] Next, still another embodiment of the present invention will
be described with reference to FIG. 25. FIG. 25 shows a refrigerant
circuit diagram of a refrigerating device 70 in this case. It is to
be noted that in FIG. 25, components denoted with the same
reference numerals as those of Embodiment 1 produce the same or
similar functions or effects. The refrigerating device 70 of the
present embodiment is different from Embodiment 8 in that third and
fourth heat absorbing means 10B, 11B are disposed instead of the
first and second heat absorbing means 10, 11.
[0287] The third heat absorbing means 10B includes: a first
capillary tube 12 in which a refrigerant from a branch point 9C
circulates; a first expansion valve 65 disposed in series to the
first capillary tube 12; a heat sink 57 for refrigerating; and a
first heat exchanger 17 disposed so as to exchange heat between a
refrigerant discharged from the heat sink 57 and a refrigerant in
the vicinity of the first capillary tube 12. The fourth heat
absorbing means 11B is disposed in parallel with the third heat
absorbing means 10B, and includes: a pressure reducing unit 3; a
gas-liquid separator 4; a second capillary tube 13 in which the
refrigerant from the gas-liquid separator 4 circulates; a second
expansion valve 66 disposed in series to the second capillary tube
13; a heat sink 58 for freezing; and a second heat exchanger 18
disposed so as to exchange heat between the refrigerant discharged
from this heat sink 58 and the refrigerant in the vicinity of the
second capillary tube 13. Moreover, a check valve 52 is disposed
between the outlet side of the heat sink 58 and the second heat
exchanger 18.
[0288] Moreover, the third heat absorbing means 10B and the fourth
heat absorbing means 11B function in mutually selectively different
temperature zones. A refrigerant pipe from a radiator 2 is branched
at the branch point 9C. One pipe is disposed as the third heat
absorbing means 10B, the other pipe is disposed as the fourth heat
absorbing means 11B, the pipes are disposed in parallel with each
other, but the pipes are combined again at a junction 9D disposed
before a suction port of a compressor 1.
[0289] Here, the pressure reducing unit 3 is constituted in such a
manner that a throttle degree is variable. This throttle degree is
changed to lower a refrigerant pressure to a predetermined pressure
before the refrigerant reaches the gas-liquid separator 4, and the
refrigerant is introduced into the gas-liquid separator 4.
Therefore, it is possible to control a ratio of gas and liquid in
the gas-liquid separator 4. It is to be noted that the first
expansion valve 65 and the second expansion valve 66 are
constituted so that the throttle degree is variable in the same
manner as in the pressure reducing unit 3.
[0290] Moreover, the third and fourth heat absorbing means 10B, 11B
are provided with the above-described constitutions. Therefore, in
a case where, for example, the pressure reducing unit 3 is totally
closed, and the first expansion valve 65 is opened, the refrigerant
circulates on the side of the first capillary tube 12, that is, the
third heat absorbing means 10B only. Conversely, when the first
expansion valve 65 is totally closed, and the pressure reducing
unit 3 and the second expansion valve 66 are opened, the
refrigerant circulates on the side of the second capillary tube,
that is, the fourth heat absorbing means 11B only.
[0291] Here, the refrigerant passed through the heat sink 57 flows
via the first heat exchanger 17 disposed in the vicinity of the
first capillary tube 12, and exchanges heat with the refrigerant in
the vicinity of the first capillary tube 12 in this first heat
exchanger 17. Thereafter, the refrigerant is returned to the
suction port of the compressor 1. The refrigerant discharged from
the heat sink 58 passes through the check valve 52 and the second
heat exchanger 18 disposed in the vicinity of the second capillary
tube 13. After the refrigerant exchanges heat with the refrigerant
in the vicinity of the second capillary tube 13 in the second heat
exchanger 18, the refrigerant is returned to the suction port of
the compressor 1.
[0292] Even in the present embodiment, even when the gas
refrigerant separated by the gas-liquid separator 4 is circulated
in fourth heat absorbing means 11B such as the second capillary
tube 13, the refrigerant cannot be used during the cooling. When
the refrigerant is returned to the suction port of a first-stage
compressing section 1A, a compression efficiency in the compressor
1 is deteriorated. To solve the problem, when the gas refrigerant
separated by the gas-liquid separator 4 is introduced into the
intermediate-pressure portion of the compressor 1, that is, between
an intermediate cooling unit 1C and a second-stage compressing
section 1B, the compression efficiency in the compressor 1 can be
improved.
[0293] Here, since the refrigerating device 70 is constituted so as
to circulate the refrigerant in the third heat absorbing means 10B
during the refrigerating operation, it is not possible to utilize a
function of a refrigerant introducing tube 6 of introducing the gas
refrigerant separated by the gas-liquid separator 4 into the
intermediate-pressure portion of the compressor 1. However, since
during the refrigerating operation, an amount of the gas
refrigerant generated in the gas-liquid separator 4 is smaller than
that during the freezing operation, a drop width of the operation
efficiency is inhibited even if the operations of the pressure
reducing unit 3, the refrigerant introducing tube 6 and the like
are stopped.
[0294] The refrigerating device 70 of the present embodiment is
applicable to a refrigerator in the same manner as in the
refrigerating device 50 of Embodiment 8.
Embodiment 10
[0295] Embodiment 10 of the present invention will be described
with reference to FIG. 26. FIG. 26 shows a refrigerant circuit
diagram of a refrigerating device 90 in the present embodiment. It
is to be noted that in FIG. 26, components denoted with the same
reference numerals as those of the above-described embodiments
produce the same or similar functions or effects. The refrigerating
device 90 of the present embodiment is different from Embodiment 8
in that a drier 95 is disposed in a refrigerant pipe 4A between an
outlet side of a third capillary tube 31 and an inlet side of a
gas-liquid separator 4.
[0296] The drier 95 includes an adsorbing section as means for
removing a water content from a refrigerating cycle in a container
formed into a substantially columnar hollow member. In this
adsorbing section, activated alumina, zeolite, molecular sieve or
the like is used as a drying agent to be introduced into the
gas-liquid separator 4.
[0297] As described above, since the refrigerating device 90 is
provided with the drier 95, a gas-liquid separator 4-4 structured
as shown in FIG. 27 is applicable as the gas-liquid separator
4.
[0298] FIG. 27 is a schematic sectional view of the gas-liquid
separator 4-4. This gas-liquid separator 4-4 is different from the
above-described gas-liquid separators 4, 4-1, 4-2, and 4-3 in that
any adsorbing section is not disposed in a sealed container 80.
This can reduce costs of the gas-liquid separator.
[0299] As described above, according to the present embodiment,
carbon dioxide is used as the refrigerant. Therefore, a
high-pressure part of a compression refrigerating cycle has a much
higher pressure as compared with the use of a hydrofluorocarbon
(HFC) refrigerant or a hydrocarbon (HC) refrigerant as in a
conventional art. However, since the refrigerating device 90 of the
present embodiment is provided with the third capillary tube 31 to
form a two-stage expansion cycle, and the drier 95 is disposed in
an intermediate-pressure part of the refrigerating cycle, the
drying agent can be prevented from being crushed owing to the
high-temperature high-pressure refrigerant, and a water content can
be removed from the refrigerant.
[0300] It is to be noted that in the refrigerating device 90 of the
present embodiment, the gas-liquid separators 4, 4-1, 4-2, and 4-3
are applicable instead of the gas-liquid separator 4-4. In this
case, there is a problem of cost increase or the like, but,
needless to say, a capability of removing the water content in the
refrigerating cycle is improved, and the gas-liquid separator
becomes valid depending on use states or use conditions of the
refrigerating device 90.
[0301] Moreover, the refrigerating device 90 of the present
embodiment is applicable to a refrigerator in the same manner as in
the above-described embodiments, The present invention has been
described above in accordance with the embodiment, but the present
invention is not limited to the embodiment, and various
modifications are possible. For example, a carbon dioxide
refrigerant is introduced into a refrigerant circuit in the
above-described embodiment, but the present invention is not
limited to the embodiment, and is applicable to another embodiment
in which a chlorofluorocarbon-based refrigerant is introduced.
[0302] Moreover, in the above-described embodiments, if necessary,
the capillary tube may be replaced with the expansion valve, and
the expansion valve may be replaced with the capillary tube.
* * * * *