U.S. patent application number 11/280348 was filed with the patent office on 2006-05-18 for compressor oil recovering apparatus and multi-unit air conditioner equiped with the same.
This patent application is currently assigned to LG Electronics Inc.. Invention is credited to Sung Oh Choi, Do Yong Ha, Ho Jong Jeong, Ki Bum Kim, Ki Baik Kwon.
Application Number | 20060101845 11/280348 |
Document ID | / |
Family ID | 35735413 |
Filed Date | 2006-05-18 |
United States Patent
Application |
20060101845 |
Kind Code |
A1 |
Jeong; Ho Jong ; et
al. |
May 18, 2006 |
Compressor oil recovering apparatus and multi-unit air conditioner
equiped with the same
Abstract
A multi-unit air conditioner is disclosed. The multi-unit air
conditioner includes an outdoor unit comprising at least two
compressors, a plurality of indoor units connected to the outdoor
unit, a plurality of oil separators each connected to an associated
one of the compressors to separate oil from a refrigerant
discharged from the associated compressor, an oil storage for
storing the oil separated from each oil separator, a plurality of
oil supplying tubes each having one end connected to the oil
storage, and the other end connected to an associated one of the
compressors to supply the oil stored in the oil storage to the
associated compressor, and adjusters each arranged at an associated
one of the oil supplying tubes to adjust an amount of oil supplied
from the oil storage to an associated one of the compressors in
accordance with an oil storage state of the associated
compressor.
Inventors: |
Jeong; Ho Jong; (Seoul,
KR) ; Ha; Do Yong; (Anyang-si, KR) ; Kim; Ki
Bum; (Seoul, KR) ; Kwon; Ki Baik;
(Gwangmyeong-si, KR) ; Choi; Sung Oh;
(Gwangmyeong-si, KR) |
Correspondence
Address: |
BIRCH STEWART KOLASCH & BIRCH
PO BOX 747
FALLS CHURCH
VA
22040-0747
US
|
Assignee: |
LG Electronics Inc.
|
Family ID: |
35735413 |
Appl. No.: |
11/280348 |
Filed: |
November 17, 2005 |
Current U.S.
Class: |
62/470 ; 62/468;
62/510 |
Current CPC
Class: |
F25B 2313/006 20130101;
F25B 2313/0233 20130101; F25B 31/004 20130101; F25B 13/00 20130101;
F25B 2400/075 20130101; F25B 2700/03 20130101 |
Class at
Publication: |
062/470 ;
062/468; 062/510 |
International
Class: |
F25B 43/02 20060101
F25B043/02; F25B 1/10 20060101 F25B001/10 |
Foreign Application Data
Date |
Code |
Application Number |
Nov 18, 2004 |
KR |
P2004-0094623 |
Claims
1. A compressor oil recovering apparatus comprising: a plurality of
oil separators respectively connected to a plurality of
compressors, each of the oil separators separating oil from a
refrigerant discharged from an associated one of the compressors;
an oil storage for storing the oil separated from each of the oil
separators; and a plurality of oil supplying tubes each having one
end connected to the oil storage, and the other end connected to an
associated one of the compressors, each of the oil supplying tubes
supplying the oil stored in the oil storage to the associated
compressor.
2. The compressor oil recovering apparatus according to claim 1,
further comprising: adjusters each arranged at an associated one of
the oil supplying tubes, and adapted to adjust an amount of oil
supplied from the oil storage to an associated one of the
compressors in accordance with an oil storage state of the
associated compressor.
3. The compressor oil recovering apparatus according to claim 2,
wherein each of the adjusters comprises: a float arranged in an
associated one of the compressors, and adapted to sense a level of
oil stored in the associated compressor; and a float valve for
controlling supply or cut-off of the oil supplied to the associated
compressor, and an amount of the supplied oil, based on the sensed
oil level.
4. The compressor oil recovering apparatus according to claim 3,
wherein the float valve is arranged at a position where an
associated one of the oil supplying tubes is connected to the
associated compressor.
5. The compressor oil recovering apparatus according to claim 2,
wherein each of the adjusters comprises: an oil sensor adapted to
sense an amount of oil stored in an associated one of the
compressors; and a solenoid valve adapted to control supply or
cut-off of the oil supplied to the associated compressor, and an
amount of the supplied oil, based on the sensed oil amount.
6. The compressor oil recovering apparatus according to claim 5,
wherein the oil sensor is arranged in the associated
compressor.
7. The compressor oil recovering apparatus according to claim 5,
wherein the solenoid valve is arranged at a position where an
associated one of the oil supplying tubes is connected with the
associated compressor.
8. The compressor oil recovering apparatus according to claim 1,
further comprising: strainers respectively arranged at the oil
supplying tubes, and adapted to filter the oil supplied to the
compressors to remove foreign matter contained in the oil.
9. The compressor oil recovering apparatus according to claim 1,
wherein the oil storage is connected with the oil separators by a
plurality of oil recovering tubes, respectively.
10. The compressor oil recovering apparatus according to claim 5,
wherein at least one of the compressors comprises a
variable-capacity compressor.
11. A multi-unit air conditioner comprising: an outdoor unit
comprising a plurality of compressors, and an outdoor heat
exchanger; a plurality of indoor units connected to the outdoor
unit, each of the indoor units comprising an indoor heat exchanger;
a plurality of oil separators respectively connected to the
compressors, each of the oil separators separating oil from a
refrigerant discharged from an associated one of the compressors;
an oil storage for storing the oil separated from each of the oil
separators; and a plurality of oil supplying tubes each having one
end connected to the oil storage, and the other end connected to an
associated one of the compressors, each of the oil supplying tubes
supplying the oil stored in the oil storage to the associated
compressor.
12. The multi-unit air conditioner according to claim 11, further
comprising: an outdoor fan arranged in the outdoor unit, and
adapted to suck outdoor air into the outdoor unit, and then to
discharge the air from the outdoor unit to the atmosphere; and
indoor fans each arranged in an associated one of the indoor units,
and adapted to suck air from a confined space into the associated
indoor unit, and then to discharge the air from the associated
indoor unit to the confined space.
13. The multi-unit air conditioner according to claim 11, further
comprising: adjusters each arranged at an associated one of the oil
supplying tubes, and adapted to adjust an amount of oil supplied
from the oil storage to an associated one of the compressors in
accordance with an oil storage state of the associated
compressor.
14. The multi-unit air conditioner according to claim 13, wherein
each of the adjusters comprises: a float arranged in an associated
one of the compressors, and adapted to sense a level of oil stored
in the associated compressor; and a float valve for controlling
supply or cut-off of the oil supplied to the associated compressor,
and an amount of the supplied oil, based on the sensed oil
level.
15. The multi-unit air conditioner according to claim 14, wherein
the float valve is arranged at a position where an associated one
of the oil supplying tubes is connected with the associated
compressor.
16. The multi-unit air conditioner according to claim 13, wherein
each of the adjusters comprises: an oil sensor adapted to sense an
amount of oil stored in an associated one of the compressors; and a
solenoid valve adapted to control supply or cut-off of the oil
supplied to the associated compressor, and an amount of the
supplied oil, based on the sensed oil amount.
17. The multi-unit air conditioner according to claim 16, wherein
the oil sensor is arranged in the associated compressor.
18. The multi-unit air conditioner according to claim 16, wherein
the solenoid valve is arranged at a position where an associated
one of the oil supplying tubes is connected with the associated
compressor.
19. The multi-unit air conditioner according to claim 11, further
comprising: strainers respectively arranged at the oil supplying
tubes, and adapted to filter the oil supplied to the compressors to
remove foreign matter contained in the oil.
20. The multi-unit air conditioner according to claim 11, wherein
the oil storage comprises a storing container in which a single
storing chamber is defined.
21. The multi-unit air conditioner according to claim 11, wherein
the oil storage is connected with the oil separators by a plurality
of oil recovering tubes, respectively.
22. The multi-unit air conditioner according to claim 11, wherein
at least one of the compressors comprises a variable-capacity
compressor.
Description
[0001] This application claims the benefit of Korean Patent
Application No.P2004-94623, filed on Nov. 18, 2004 which is hereby
incorporated by reference as if fully set forth herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an air conditioner, and
more particularly, to a compressor oil recovering apparatus for a
multi-unit air conditioner.
[0004] 2. Discussion of the Related Art
[0005] Generally, air conditioners perform procedures of
compressing, condensing, expanding and evaporating a refrigerant to
cool and/or heat a confined space. Such air conditioners are
classified into a cooling type wherein a refrigerant flows only in
one direction through a refrigerant cycle, to supply cold air to a
confined space, and a cooling and heating type wherein a
refrigerant flows bi-directionally in a selective manner through a
refrigerant cycle, to selectively supply cold air or hot air to a
confined space.
[0006] Also, such air conditioners are classified into a general
type wherein one indoor unit is connected to one outdoor unit, and
a multi-unit type wherein a plurality of indoor units are connected
to one outdoor unit. For the multi-unit type, an air conditioner
may be implemented which includes at least one outdoor unit.
[0007] Meanwhile, the outdoor unit of such a multi-unit air
conditioner includes at least one compressor corresponding to the
load of the indoor units, and an oil separator connected to a
refrigerant discharge line of the compressor, and adapted to
separate oil from a refrigerant discharged from the compressor.
[0008] The compressor sucks low-temperature and low-pressure
refrigerant gas, compresses the sucked refrigerant gas into
high-temperature and high-pressure refrigerant gas, and discharges
the resulting refrigerant gas. When such high-temperature and
high-pressure refrigerant gas is discharged from the compressor,
oil present in the compressor is also discharged together with the
refrigerant. The oil contained in the discharged refrigerant is
again fed to the compressor after being separated from the
refrigerant in the oil separator.
[0009] In the conventional multi-unit air conditioner, however, a
problem occurs when the oil separated by the oil separator is
returned to the compressor via a refrigerant suction line.
[0010] That is, the oil separated by the oil separator may be
re-discharged together with the refrigerant discharged from the
compressor via the refrigerant discharge line, without being
returned to the compressor via the refrigerant suction line. This
is because there is a pressure difference between the refrigerant
suction line and the refrigerant discharge line due to the flow
rate of the refrigerant discharged through the refrigerant
discharge line. As a result, shortage of oil may occur in the
compressor.
[0011] Such oil shortage may cause abrasion and performance
degradation of the compressor. As a result, the compressor exhibits
a degradation in reliability.
[0012] The performance degradation of the compressor results in a
degradation in the efficiency of the multi-unit air conditioner
using the compressor, thereby causing a degradation in
cooling/heating performance.
SUMMARY OF THE INVENTION
[0013] Accordingly, the present invention is directed to a
compressor oil recovering apparatus and a multi-unit air
conditioner equipped with the same that substantially obviate one
or more problems due to limitations and disadvantages of the
related art.
[0014] An object of the present invention is to provide a
multi-unit air conditioner which includes a compressor oil
recovering apparatus capable of effectively recovering oil, using a
simple configuration.
[0015] Additional advantages, objects, and features of the
invention will be set forth in part in the description which
follows and in part will become apparent to those having ordinary
skill in the art upon examination of the following or may be
learned from practice of the invention. The objectives and other
advantages of the invention may be realized and attained by the
structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
[0016] To achieve these objects and other advantages and in
accordance with the purpose of the invention, as embodied and
broadly described herein, a compressor oil recovering apparatus
comprises: a plurality of oil separators respectively connected to
a plurality of compressors, each of the oil separators separating
oil from a refrigerant discharged from an associated one of the
compressors; an oil storage for storing the oil separated from each
of the oil separators; and a plurality of oil supplying tubes each
having one end connected to the oil storage, and the other end
connected to an associated one of the compressors, each of the oil
supplying tubes supplying the oil stored in the oil storage to the
associated compressor.
[0017] The compressor oil recovering apparatus may further comprise
adjusters each arranged at an associated one of the oil supplying
tubes, and adapted to adjust an amount of oil supplied from the oil
storage to an associated one of the compressors in accordance with
an oil storage state of the associated compressor.
[0018] Each of the adjusters may comprise a float arranged in an
associated one of the compressors, and adapted to sense a level of
oil stored in the associated compressor, and a float valve for
controlling supply or cut-off of the oil supplied to the associated
compressor, and an amount of the supplied oil, based on the sensed
oil level.
[0019] The float valve may be arranged at a position where an
associated one of the oil supplying tubes is connected to the
associated compressor.
[0020] Each of the adjusters may comprise an oil sensor adapted to
sense an amount of oil stored in an associated one of the
compressors, and a solenoid valve adapted to control supply or
cut-off of the oil supplied to the associated compressor, and an
amount of the supplied oil, based on the sensed oil amount.
[0021] The oil sensor may be arranged in the associated
compressor.
[0022] The solenoid valve may be arranged at a position where an
associated one of the oil supplying tubes is connected with the
associated compressor.
[0023] The compressor oil recovering apparatus may further comprise
strainers respectively arranged at the oil supplying tubes, and
adapted to filter the oil supplied to the compressors to remove
foreign matter contained in the oil.
[0024] The oil storage may be connected with the oil separators by
a plurality of oil recovering tubes, respectively.
[0025] At least one of the compressors may comprise a
variable-capacity compressor.
[0026] In another aspect of the present invention, a multi-unit air
conditioner comprises: an outdoor unit comprising a plurality of
compressors, and an outdoor heat exchanger; a plurality of indoor
units connected to the outdoor unit, each of the indoor units
comprising an indoor heat exchanger; a plurality of oil separators
respectively connected to the compressors, each of the oil
separators separating oil from a refrigerant discharged from an
associated one of the compressors; an oil storage for storing the
oil separated from each of the oil separators; and a plurality of
oil supplying tubes each having one end connected to the oil
storage, and the other end connected to an associated one of the
compressors, each of the oil supplying tubes supplying the oil
stored in the oil storage to the associated compressor.
[0027] The indoor units may be connected to the outdoor unit by a
refrigerant line.
[0028] The multi-unit air conditioner may further comprise indoor
fans each arranged in an associated one of the indoor units, and
adapted to suck air from a confined space into the associated
indoor unit, and then to discharge the air from the associated
indoor unit to the confined space.
[0029] The multi-unit conditioner may further comprise an outdoor
fan arranged in the outdoor unit, and adapted to suck outdoor air
into the outdoor unit, and then to discharge the air from the
outdoor unit to the atmosphere.
[0030] The multi-unit air conditioner may further comprise
adjusters each arranged at an associated one of the oil supplying
tubes, and adapted to adjust an amount of oil supplied from the oil
storage to an associated one of the compressors in accordance with
an oil storage state of the associated compressor.
[0031] Each of the adjusters may comprise a float arranged in an
associated one of the compressors, and adapted to sense a level of
oil stored in the associated compressor, and a float valve for
controlling supply or cut-off of the oil supplied to the associated
compressor, and an amount of the supplied oil, based on the sensed
oil level.
[0032] The float valve may be arranged at a position where an
associated one of the oil supplying tubes is connected with the
associated compressor.
[0033] Each of the adjusters may comprise an oil sensor adapted to
sense an amount of oil stored in an associated one of the
compressors, and a solenoid valve adapted to control supply or
cut-off of the oil supplied to the associated compressor, and an
amount of the supplied oil, based on the sensed oil amount.
[0034] The oil sensor may be arranged in the associated compressor.
The solenoid valve may be arranged at a position where an
associated one of the oil supplying tubes is connected with the
associated compressor.
[0035] The multi-unit air conditioner may further comprise
strainers respectively arranged at the oil supplying tubes, and
adapted to filter the oil supplied to the compressors to remove
foreign matter contained in the oil.
[0036] The oil storage may be connected with the oil separators by
a plurality of oil recovering tubes, respectively.
[0037] The oil storage may comprise a storing container in which a
single storing chamber is defined.
[0038] At least one of the compressors may comprise a
variable-capacity compressor.
[0039] In another aspect of the present invention, a multi-unit air
conditioner comprises: an outdoor unit comprising at least two
compressors; a plurality of indoor units connected to the outdoor
unit; a plurality of oil separators respectively connected to the
compressors, each of the oil separators separating oil from a
refrigerant discharged from an associated one of the compressors;
an oil storage for storing the oil separated from each of the oil
separators; a plurality of oil supplying tubes each having one end
connected to the oil storage, and the other end connected to an
associated one of the compressors, each of the oil supplying tubes
supplying the oil stored in the oil storage to the associated
compressor; and adjusters each arranged at an associated one of the
oil supplying tubes, and adapted to adjust an amount of oil
supplied from the oil storage to an associated one of the
compressors in accordance with an oil storage state of the
associated compressor.
[0040] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0041] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiment(s) of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
[0042] FIG. 1 is a partially-broken perspective view illustrating a
multi-unit air conditioner according to a first embodiment of the
present invention;
[0043] FIG. 2 is a schematic view illustrating a refrigerant cycle
established during a cooling operation of the multi-unit air
conditioner shown in FIG. 1;
[0044] FIG. 3 is a schematic view illustrating a compressor oil
recovering apparatus shown in FIG. 2; and
[0045] FIG. 4 is a schematic view illustrating a compressor oil
recovering apparatus according to a second embodiment of the
present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0046] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers will be used throughout the drawings to
refer to the same or like parts.
[0047] FIGS. 1 to 3 illustrate a multi-unit air conditioner
according to a first embodiment of the present invention. This
multi-unit air conditioner will be described with reference to
FIGS. 1 to 3.
[0048] FIG. 1 is a partially-broken perspective view illustrating
the multi-unit air conditioner according to the first embodiment of
the present invention. FIG. 2 is a schematic view illustrating a
refrigerant cycle established during a cooling operation of the
multi-unit air conditioner shown in FIG. 1. FIG. 3 is a schematic
view illustrating a compressor oil recovering apparatus shown in
FIG. 2.
[0049] As shown in FIGS. 1 and 2, the multi-unit air conditioner
according to the first embodiment of the present invention includes
an outdoor unit 80, and a plurality of indoor units 51, 52, 53, and
54. The multi-unit air conditioner also includes a refrigerant line
100 for connecting the indoor units 51, 52, 53, and 54 to the
outdoor unit 80.
[0050] The refrigerant line 100 includes a first refrigerant line
110 connected to a receiver 87c included in the outdoor unit 80 at
one end of the first refrigerant line 110, and branched into a
plurality of branch lines 111, 112, 113, and 114 at the other end
of the refrigerant line 110 such that the refrigerant line 110 is
connected to one end of each of the indoor units 51, 52, 53, and 54
via an associated one of the branch lines 111, 112, 113, and 114.
The refrigerant line 100 also includes a second refrigerant line
120 connected to an accumulator 87a included in the outdoor unit 80
at one end of the second refrigerant line 120, and branched into a
plurality of branch lines 121, 122, 123, and 124 at the other end
of the refrigerant line 120 such that the refrigerant line 120 is
connected to the other end of each of the indoor units 51, 52, 53,
and 54 via an associated one of the branch lines 121, 122, 123, and
124.
[0051] Accordingly, a refrigerant is introduced into the indoor
units 51, 52, 53, and 54 through the first refrigerant line 110.
Flows of the refrigerant respectively emerging from the indoor
units 51, 52, 53, and 54 are joined through the second refrigerant
line 120 which, in turn, supplies the refrigerant to the outdoor
unit 80.
[0052] Each of the indoor units 51, 52, 53, and 54 includes an
indoor fan 74 adapted to force indoor air in a confined space to be
sucked into the associated indoor unit 51, 52, 53, or 54, and then
to be discharged into the confined space. Each indoor unit 51, 52,
53, or 54 also includes an indoor heat exchanger 72 adapted to
cause the indoor air sucked into the associated indoor unit 51, 52,
53, or 54 to heat-exchange with the refrigerant such that the
indoor air is cooled or heated.
[0053] The outdoor unit 80 includes an outdoor fan 81 adapted to
force outdoor air to be sucked into the outdoor unit 80, and then
to be discharged into the atmosphere, and an outdoor heat exchanger
82 adapted to cause the outdoor air sucked into the outdoor unit 80
by the outdoor fan 81 to heat-exchange with the refrigerant. The
outdoor unit 80 also includes a plurality of compressors 83 and 84,
each adapted to compress the refrigerant, and a plurality of oil
separators 85 and 86 connected to refrigerant discharge lines 83a
and 84a extending from the compressors 83 and 84, and adapted to
separate oil from the refrigerant discharged from the compressors
83 and 84, respectively.
[0054] Although not shown, each of the compressors 83 and 84
includes a compressing section having a compressing chamber, in
which the refrigerant is compressed, a motor section for reducing
the volume of the compressing chamber for the compression of the
refrigerant, and an oil pump for pumping oil for lubrication of the
motor section or compressing section.
[0055] At least one of the compressors 83 and 84 is of a variable
capacity type, and the remaining one or ones of the compressors 83
and 84 are of a constant-speed type. In the illustrated case, the
compressor 83 is of the variable capacity type, and the compressor
84 is of the constant-speed type. When the load to be processed by
the indoor units 51, 52, 53, and 54 (hereinafter, referred to as a
"indoor unit load") is small, for example, when only one or two of
the indoor units 51, 52, 53, and 54 operate, only the
variable-capacity compressor 83 is driven to cope with the indoor
unit load. On the other hand, in the case of a large indoor unit
load, for example, when three or more of the indoor units 51, 52,
53, and 54 operate, it is desired to operate not only the
variable-capacity compressor 83, but also the constant-speed
compressor 84.
[0056] The multi-unit air conditioner according to the first
embodiment of the present invention further includes a common
accumulator 87a arranged in the outdoor unit 80 while being
connected to respective refrigerant suction line 83b and 84b of the
variable-capacity compressor 83 and constant-speed compressor 84.
The common accumulator 87a accumulates refrigerant liquid so that
only refrigerant gas is introduced into the variable-capacity
compressor 83 and constant-speed compressor 84.
[0057] The multi-unit air conditioner according to the first
embodiment of the present invention further includes a 4-way valve
87b arranged in the outdoor unit 80 to change the path of the
refrigerant such that the refrigerant emerging from the oil
separators 85 and 86 is selectively introduced into the indoor heat
exchangers 72 or into the outdoor heat exchanger 82, thereby
enabling the indoor units 51, 52, 53, and 54 to be used as coolers
or heaters.
[0058] The receiver 87c arranged in the outdoor unit 80 is also
included in the multi-unit air conditioner according to the first
embodiment of the present invention. The receiver 87c not only
stores a surplus of refrigerant, but also causes only refrigerant
liquid to be circulated through the indoor units during the cooling
operation.
[0059] The multi-unit air conditioner according to the first
embodiment of the present invention further includes an orifice or
electronic expansion valve 88a arranged at the refrigerant line 100
between the outdoor heat exchanger 82 and each of the indoor heat
exchangers 72, and adapted to expand the refrigerant emerging from
the outdoor heat exchanger 82 and the associated indoor heat
exchanger 72 into a low-temperature and low-pressure state. The
multi-unit air conditioner also includes an electronic expansion
valve 88b arranged in the outdoor unit 80, and adapted to control
the flow rate of the refrigerant circulating through the outdoor
unit 80, and thus, the refrigerant cycle.
[0060] The multi-unit air conditioner according to the first
embodiment of the present invention further includes check valves
89 respectively arranged in the refrigerant discharge lines 83a and
84a of the variable-capacity compressor 83 and constant-speed
compressor 84.
[0061] Meanwhile, as shown in FIGS. 2 and 3, the multi-unit air
conditioner further includes a compressor oil recovering apparatus.
The compressor oil recovering apparatus includes an oil storage 151
for receiving and storing oil separated from the oil separators 85
and 86, and a plurality of oil supplying tubes 153 and 154 each
connected between the oil storage 151 and an associated one of the
compressors 83 and 84 to supply the oil stored in the oil storage
151 to the associated compressor 83 or 84.
[0062] The oil storage 151 may be a storing container defined with
a single storing chamber therein. The oil storage 151 is connected
to the plural separators 85 and 86 via a plurality of oil
recovering tubes 156 and 157, respectively.
[0063] The compressor oil recovering apparatus further includes
adjusters each arranged for adjusting the amount of oil supplied
from the oil storage 151 to an associated one of the compressors 83
and 84 in accordance with the oil storage state of the associated
compressor 83 or 84.
[0064] As shown in FIG. 3, each adjuster includes a float 159a
adapted to sense the level of the surface of oil stored in the
associated compressor 83 or 84. Each adjuster also includes a float
valve 159 for controlling the supply or cut-off of the oil supplied
to the associated compressor 83 or 84, and the amount of the
supplied oil in accordance with the oil surface level sensed by the
float 159a.
[0065] It is preferred that the float valve 159 be arranged at an
end of an associated one of the oil supply tubes 153 and 154
arranged adjacent to the associated compressor 83 or 84.
[0066] The compressor oil recovering apparatus further includes
strainers 153a and 154a respectively arranged at the oil supplying
tubes 153 and 154, and adapted to filter the oil supplied to the
compressors 83 and 84 to remove foreign matter contained in the
oil.
[0067] Hereinafter, a procedure for recovering the compressor oil
in the multi-unit air conditioner having the above-described
configuration according to the illustrated embodiment of the
present invention will be described.
[0068] When the refrigerant emerging from the compressors 83 and 84
passes through the 4-way valve 87b to be circulated through the
outdoor heat exchanger 82, expansion device 88a, and indoor heat
exchangers 72, in this order, a cooling cycle is established to
cause the indoor units 51, 52, 53, and 54 to operate in cooling
mode. When the refrigerant circulates in a direction reverse to
that of the cooling mode in accordance with the change of the
refrigerant flow by the 4-way valve 87b, a heating cycle is
established to operate the indoor units 51, 52, 53, and 54 in
heating mode. The following description will be given only in
conjunction with the case in which the multi-unit air conditioner
establishes the cooling cycle.
[0069] First, when the multi-unit air conditioner operates such
that a part of the indoor units 51, 52, 53, and 54, for example,
one or two of the indoor units 51, 52, 53, and 54, operates in
cooling mode, only the variable-capacity compressor 83 of the
outdoor unit 80 operates. In this case, the constant-speed
compressor 83 of the outdoor unit 80 does not operate.
[0070] Accordingly, the variable-capacity compressor 83 compresses
the refrigerant into a high-temperature and high-pressure state,
and then discharges the compressed refrigerant through the
refrigerant discharge line 83a together with oil. A large part of
the oil discharged together with the refrigerant is separated from
the refrigerant while passing through the oil separator 85. The
remaining oil is circulated through the refrigerant cycle, together
with the refrigerant.
[0071] The refrigerant emerging from the oil separator 85 is
introduced into the indoor heat exchanger or indoor heat exchangers
72 of the indoor unit or indoor units, which operate in cooling
mode, after passing through the 4-way valve 87b, outdoor heat
exchanger 82, and expansion device or expansion devices 88a, in
this order. The refrigerant is then evaporated while cooling air
present around the indoor heat exchanger or indoor heat exchangers
72, thereby causing the indoor unit or indoor units to function as
a cooler or coolers. The refrigerant is subsequently returned to
the variable-capacity compressor 83.
[0072] Meanwhile, the oil separated from the refrigerant in the oil
separator 85 is fed to the oil storage 151 through the oil
recovering tube 156, and is stored in the oil storage 151.
Subsequently, the stored oil is directly re-supplied to the
variable-capacity compressor 83 through the oil supplying tube
153.
[0073] The supply or cut-off of the oil supplied to the
variable-capacity compressor 83 and the flow rate of the supplied
oil are controlled by the float valve 159 arranged at the oil
supplying tube 153 in accordance with the oil storage state of the
variable-capacity compressor 83.
[0074] Thus, in the multi-unit air conditioner according to the
illustrated embodiment of the present invention, the oil separated
from the refrigerant by the oil separator 85 is directly supplied
to the variable-capacity compressor 83 through the oil storage 151
and oil supplying tube 153, contrary to the conventional case in
which the separated oil is supplied to the variable-capacity
compressor 83 through the refrigerant suction line 83b.
Accordingly, it is possible to prevent shortage of oil from
occurring in the variable-capacity compressor 83.
[0075] Meanwhile, when the variable-capacity compressor 83 operates
for a prolonged period of time, the oil present in the cooling
cycle is concentrated in the variable-capacity compressor 83. As a
result, non-uniform oil distribution occurs between the compressors
83 and 84.
[0076] In the multi-unit air conditioner according to the
illustrated embodiment of the present invention, such non-uniform
oil distribution is prevented by the oil storage 151 connected with
the oil separators 85 and 86, the oil supplying tubes 153 and 154,
which supply the oil stored in the oil storage 151 to the
compressors 83 and 84, and the float valve 159, which controls the
oil supplied to the compressors 83 and 84 via the oil supplying
tubes 153 and 154.
[0077] That is, the float valve 159 senses the surface level of oil
corresponding to the minimum oil amount of each of the compressors
83 and 84. Based on the sensed oil surface level, the oil stored in
the oil storage 151 is supplied to the compressor 83 or 84, in
which shortage of oil has occurred. Accordingly, it is possible to
prevent non-uniform oil distribution between the compressors 83 and
84.
[0078] Since oil is supplied to the compressor 83 or 84, in which
shortage of oil has occurred, immediately at the point of time when
non-uniform oil distribution between the compressors 83 and 84
occurs, it is possible to achieve an enhancement in the performance
of the compressors 83 and 84, and thus, the efficiency of the
multi-unit air conditioner.
[0079] FIG. 4 is a schematic view illustrating a compressor oil
recovering apparatus according to a second embodiment of the
present invention.
[0080] Referring to FIG. 4, the compressor oil recovering
apparatus, which is included in a multi-unit air conditioner
according to the second embodiment of the present invention,
includes oil sensors 259a each arranged in an associated one of the
compressors 83 and 84, and adapted to sense the amount of oil
stored in the associated compressor 83 or 84. The compressor oil
recovering apparatus also includes solenoid valves 259 each adapted
to control the supply or cut-off of the oil supplied to an
associated one of the compressor 83 and 84, and the amount of the
supplied oil in accordance with the oil amount sensed by an
associated one of the oil sensors 259a.
[0081] In this case, the oil sensors 259a substitute for the floats
159 described in the first embodiment, and the solenoid valves 259
substitute for the float valves 159 of the first embodiment. The
oil sensors 259a and solenoid valves 259 perform functions similar
to those of the first embodiment.
[0082] Each solenoid valve 259 may be arranged at a position where
an associated one of the oil supplying tubes 153 and 154 is
connected with an associated one of the compressors 83 and 84.
[0083] In accordance with the second embodiment of the present
invention, the multi-unit air conditioner also includes strainers
153a and 154a respectively arranged at the oil supplying tubes 153
and 154, and adapted to filter the oil supplied to the compressors
83 and 84 to remove foreign matter contained in the oil.
[0084] In the multi-unit air conditioner according to the
illustrated embodiment of the present invention, each solenoid
valve 259 is controlled, based on the amount of oil sensed by the
float valve 159 arranged in the associated compressor 83 or 84.
Based on the sensed oil amount, an amount of oil required in the
associated compressor 83 or 84 is supplied to the associated
compressor 83 or 84. Accordingly, it is possible to prevent oil
shortage and non-uniform oil distribution from occurring during the
operation of the compressors 83 and 84.
[0085] The multi-unit air conditioner according to the present
invention, which has been described, has various effects.
[0086] First, in accordance with the present invention, the oil,
which is separated from the refrigerant in the oil separators, is
smoothly supplied to the oil storing section of each compressor.
Accordingly, there are advantages of preventing abrasion and noise
from being generated in the compressors, increasing the life of the
compressors, and enhancing the system efficiency of the air
conditioner.
[0087] Second, in accordance with the present invention, the oil
discharged from each compressor together with the refrigerant is
recovered to the compressor via a single oil path defined by the
oil separator, oil recovering tube, oil storage, and oil supplying
tube. Accordingly, there is an advantage in that it is possible to
efficiently recover compressor oil.
[0088] Third, in accordance with the present invention, it is
possible to continuously supply an appropriate amount of oil, based
on the oil storage state of each compressor. Accordingly, it is
possible to prevent oil shortage in the compressors, and
non-uniform oil distribution between the compressors, and thus, to
achieve an enhancement in the performance of the compressors.
[0089] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention
without departing from the spirit or scope of the inventions. Thus,
it is intended that the present invention covers the modifications
and variations of this invention provided they come within the
scope of the appended claims and their equivalents.
* * * * *