U.S. patent application number 14/899226 was filed with the patent office on 2016-05-12 for refrigeration compression system using two compressors.
The applicant listed for this patent is CHIYODA CORPORATION. Invention is credited to Yoshitsugi Kikkawa, Hirohiko Kikuchi, Toshiya Momose, Masaaki Oishi, Koichiro Sakai.
Application Number | 20160131422 14/899226 |
Document ID | / |
Family ID | 52392829 |
Filed Date | 2016-05-12 |
United States Patent
Application |
20160131422 |
Kind Code |
A1 |
Kikkawa; Yoshitsugi ; et
al. |
May 12, 2016 |
REFRIGERATION COMPRESSION SYSTEM USING TWO COMPRESSORS
Abstract
Apparatus for compressing gaseous refrigerant for use in a
refrigeration circuit of a liquefaction plant comprises a
refrigeration circuit (1) and two compressors (10, 20) that are
functionally connected to the refrigeration circuit. One of the
compressors is provided with a double suction configuration, and
the outlets and the inlets of the first and second compressors are
connected at least partly in a mutually parallel flow configuration
such that the refrigerant flow that leaves the refrigeration
circuit from a plurality of outlets thereof is distributed between
the two compressors before joining at the inlet of the
refrigeration circuit.
Inventors: |
Kikkawa; Yoshitsugi;
(Kanagawa, JP) ; Oishi; Masaaki; (Kanagawa,
JP) ; Momose; Toshiya; (Kanagawa, JP) ;
Kikuchi; Hirohiko; (Kanagawa, JP) ; Sakai;
Koichiro; (Kanagawa, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
CHIYODA CORPORATION |
Yokohama-shi, Kanagawa |
|
JP |
|
|
Family ID: |
52392829 |
Appl. No.: |
14/899226 |
Filed: |
July 26, 2013 |
PCT Filed: |
July 26, 2013 |
PCT NO: |
PCT/JP2013/004568 |
371 Date: |
December 17, 2015 |
Current U.S.
Class: |
62/606 |
Current CPC
Class: |
F25B 2400/13 20130101;
F25J 1/0087 20130101; F25J 1/0216 20130101; F25J 1/0055 20130101;
F25J 1/0022 20130101; F25J 1/0047 20130101; F25J 1/0052 20130101;
F25J 1/0294 20130101; F25J 1/0283 20130101; F25B 40/04 20130101;
F25B 2400/23 20130101 |
International
Class: |
F25J 1/00 20060101
F25J001/00 |
Claims
1. Apparatus for compressing gaseous refrigerant for use in a
refrigeration circuit of a liquefaction plant, the apparatus
comprising: a refrigeration circuit including an inlet for
refrigerant at a refrigeration pressure, a low pressure outlet for
gaseous refrigerant at a low pressure, a high pressure outlet for
gaseous refrigerant at a high pressure and at least one
intermediate pressure outlet for gaseous refrigerant at an
intermediate pressure; a first compressor received in a first
casing and provided with a double suction configuration including
at least two main inlets and one outlet; a second compressor
received in a second casing separate from the first casing and
having an at least one inlet and an outlet, the outlet of the
second compressor being connected to the inlet of the refrigeration
circuit; and a common power source including an output shaft for
driving the first and second compressors; wherein the first and
second compressors are provided with inlets and outlets that are
functionally connected to the inlet and the outlets of the
refrigeration circuit, and the outlets and the inlets of the first
and second compressors are connected at least partly in a mutually
parallel flow configuration.
2. The apparatus according to claim 1, wherein the two main inlets
of the first compressor are commonly connected in a symmetric
configuration.
3. The apparatus according to claim 2, wherein the two main inlets
of the first compressor are connected to the low pressure outlet of
the refrigeration circuit.
4. The apparatus according to claim 3, wherein the first compressor
is further provided with a pair of side inlets in a symmetric
configuration that are connected to the intermediate pressure
outlet of the refrigeration circuit.
5. The apparatus according to claim 2, wherein the two main inlets
of the first compressor are connected to the intermediate pressure
outlet of the refrigeration circuit.
6. The apparatus according to claim 1, wherein the two main inlets
of the first compressor are connected to different outlets of the
refrigeration circuit.
7. The apparatus according to claim 1, wherein the second
compressor is provided with a straight suction configuration.
8. The apparatus according to claim 7, wherein the outlet of the
second compressor is connected to the inlet of the refrigeration
circuit via an economizer.
9. The apparatus according to claim 1, wherein the second
compressor is provided with a double suction configuration.
10. The apparatus according to claim 1, wherein the outlet of the
first compressor is connected to the inlet of the refrigeration
circuit.
11. The apparatus according to claim 1, wherein the outlet of the
first compressor is connected to a side inlet of the second
compressor.
12. The apparatus according to claim 1, wherein the refrigeration
circuit comprises two intermediate pressure outlets for gaseous
refrigerant at intermediate pressures.
Description
TECHNICAL FIELD
[0001] The present invention relates to a refrigeration compression
system for use in a refrigeration circuit of a liquefaction plant,
and in particular to a refrigeration compression system that can be
constructed as a compact unit for a given production rate.
BACKGROUND ART
[0002] Natural gas is known to be environmentally favorable as
compared with other fossil fuels and nuclear fuels, but is required
to be processed in an appropriate manner before it can be delivered
to the final users. The cost for such processing is highly
important for the natural gas to be competitive with other forms of
fuels. Most significantly, natural gas is most often required to be
liquefied for the convenience of storage and delivery to the final
users, and the cost of liquefaction accounts for a large part of
the cost of natural gas. In large liquefaction plants, liquefaction
of natural gas is usually accomplished by compressing the natural
gas by using a series of compressors which are powered by gas
turbine drivers, and removing heat from the compressed natural gas
by using heat exchangers.
[0003] In general, the cost of liquefaction can be reduced by using
a refrigerant system with a higher refrigeration duty. The C3 MR
(propane pre-cooled mixed refrigerant process) and the optimized
cascade process are the two processes that are currently most
widely used. These processes use C3 refrigerant for the pre-cooling
of the process flow, and it is the pre-cooling process that imposes
the most critical design issue in increasing the production rate of
the system.
[0004] The production rate of the pre-cooling process can be
increased by using larger compressors that can accommodate larger
inlet volumes, but there is a limit to the size of the compressors
for the given driver speed. A simple method to increase the
compressor inlet volume is to increase the impeller diameter.
However, the required yield strength of the impeller tip would
increase so sharply as the impeller diameter is increased that the
difficulty and cost of manufacture become unacceptable once a
certain limit is reached. Also, as the inlet flow Mach number is
increased, the operating range of the compressor is narrowed, and
the efficiency of the compressor starts dropping sharply. The
problem is particularly acute because the sonic velocity in LP C3
refrigerant is very low, typically approximately 230 m/sec. As a
result, the impeller size at the LP stage would be limited below
1,320 mm when the rotor speed is selected at the typically speed of
3,600 rpm.
[0005] Also, the last stage of the compressor must treat a high
volume flow particularly when a side-stream compressor machine is
used as is often the case in large refrigeration plants. This will
lead to a drop in aerodynamic performance because of the need to
select a large flow coefficient impeller in order to handle the
large flow rate with a limited size of the impeller.
[0006] The flow coefficient is one of the dimensionless quantities
used by the manufacturers to show the impeller performance, and is
expressed by the formula given below.
F=Q.sub.0/{(pi/4)D.sup.2U2}
[0007] where F: flow coefficient
[0008] Q: suction volume flow (m.sup.3/sec)
[0009] D: impeller diameter (m)
[0010] U2: impeller tip speed (m/s)
[0011] The proven range of the flow coefficient is below 0.155.
[0012] A liquefaction plant typically employs a number of identical
compressor trains. Therefore, designing the compressor trains in an
optimum fashion is highly important in increasing the efficiency of
the liquefaction plant.
[0013] The production rate of a C3 can be increased by using two
compressors of a limited size in separate casings in a 50%-50%
parallel scheme. However, this scheme requires a large amount of
piping in an exactly symmetric 3D configuration, and the necessary
material and labor cost prevents it from becoming a practical
solution.
[0014] It was proposed in U.S. Pat. No. 6,637,238 and U.S. Pat. No.
6,962,060 to use two compressors with the aim of minimizing the
mass flow rate at the higher pressure ends. The outlets of the two
compressors are commonly connected, and the main and side inlets of
the two compressors are connected to various outlets of the
refrigeration circuit. However, the previous proposals are not
entirely satisfactory in limiting the flow velocity at the lower
pressure inlet of the corresponding compressor.
SUMMARY OF THE INVENTION
[0015] In view of such problems of the prior art, a primary object
of the present invention is to provide apparatus for compressing
gaseous refrigerant for use in a refrigeration circuit of a
liquefaction plant which is highly compact and can still maximize
the product output rate.
[0016] A second object of the present invention is to provide
apparatus for compressing gaseous refrigerant which can maximize
the product output rate by using readily available, relatively
inexpensive compressors.
[0017] A third object of the present invention is to provide
apparatus for compressing gaseous refrigerant which can maximize
the product output rate without suffering from the problem of
reduced efficiency.
[0018] According to the present invention, such objects can be at
least partly accomplished by providing apparatus for compressing
gaseous refrigerant for use in a refrigeration circuit of a
liquefaction plant, the apparatus comprising: a refrigeration
circuit including an inlet for refrigerant at a refrigeration
pressure, a low pressure outlet for gaseous refrigerant at a low
pressure, a high pressure outlet for gaseous refrigerant at a high
pressure and at least one intermediate pressure outlet for gaseous
refrigerant at an intermediate pressure; a first compressor
received in a first casing and provided with a double suction
configuration including at least two main inlets and one outlet; a
second compressor received in a second casing separate from the
first casing and having an at least one inlet and an outlet, the
outlet of the second compressor being connected to the inlet of the
refrigeration circuit; and a common power source including an
output shaft for driving the first and second compressors; wherein
the first and second compressors are provided with inlets and
outlets that are functionally connected to the inlet and the
outlets of the refrigeration circuit, and the outlets and the
inlets of the first and second compressors are connected at least
partly in a mutually parallel flow configuration.
[0019] The use of a double suction compressor for the first
compressor allows the flow rate at the main inlets of the first
compressor to be maximized without excessively increasing the flow
velocity at the inlets. Typically, the two main inlets of the first
compressor are commonly connected in a symmetric configuration. The
outlets and the inlets of the first and second compressors being
connected at least partly in a mutually parallel flow configuration
means that the refrigerant flow that leaves the refrigeration
circuit from a plurality of outlets thereof is distributed between
the two compressors before joining at the inlet of the
refrigeration circuit.
[0020] If the two main inlets of the first compressor are connected
to the low pressure outlet of the refrigeration circuit, the flow
rate of the low pressure gaseous refrigerant to be maximized
without excessively increasing the flow velocity of the low
pressure gaseous refrigerant. If desired, the two main inlets of
the first compressor may be connected to the intermediate pressure
outlet of the refrigeration circuit.
[0021] According to a certain aspect of the present invention, the
first compressor is further provided with a pair of side inlets in
a symmetric configuration that are connected to the intermediate
pressure outlet of the refrigeration circuit.
[0022] The second compressor may be provided with either a straight
suction configuration or a double suction configuration. If the
second compressor is provided with a straight suction
configuration, the outlet of the second compressor may be connected
to the inlet of the refrigeration circuit via an economizer so that
an economical operation of the refrigeration compression system can
be achieved even when the available power of the compressor driver
is not sufficient. The two main inlets of the first compressor may
also be connected to different outlets of the refrigeration
circuit. In such a case, the first compressor having a double
suction configuration may be provided with either a symmetric or
asymmetric configuration.
[0023] The refrigeration circuit typically comprises two
intermediate pressure outlets for gaseous refrigerant at
intermediate pressures, but may also be provided with one, three or
more intermediate pressure outlets.
[0024] If the outlet of the first compressor as well as the outlet
of the second compressor is connected to the inlet of the
refrigeration circuit, the mass flow rate of the highest pressure
gaseous refrigerant can be divided between the two compressors, and
the mass flow rate at the outlet of each compressor can be avoided
from become excessive.
BRIEF DESCRIPTION OF DRAWINGS
[0025] Now the present invention is described in the following with
reference to the appended drawings, in which:
[0026] FIG. 1a is a schematic diagram of a first embodiment of the
apparatus for compressing gaseous refrigerant according to the
present invention;
[0027] FIG. 1b is a view similar to FIG. 1a showing a modification
of the first embodiment;
[0028] FIG. 2a is a view similar to FIG. 1a showing a second
embodiment of the present invention;
[0029] FIG. 2b is a view similar to FIG. 2a showing a modification
of the second embodiment; and
[0030] FIGS. 3 to 20 are views similar to FIG. 1a showing other
embodiments of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0031] FIG. 1a shows a first embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
This embodiment, as well as the other embodiments discussed in the
following, is particularly suited for use in the C3MR process. For
the details of the C3 MR (propane pre-cooled mixed refrigerant
process), reference may be made to U.S. Pat. No. 5,832,745.
However, the present invention may also be used in other
applications where refrigerant is cooled by using a refrigeration
circuit having a plurality of outlets and a compressor system
including a plurality of stages corresponding to the outlets of the
refrigeration circuit.
[0032] This apparatus comprises a propane (C3) refrigeration
circuit 1 which includes an inlet 2 and four outlets 3, 4, 5 and 6
for refrigerant at different temperatures and pressures. In the
illustrated embodiment, the four outlets consist of a low pressure
(LP) outlet 3 for refrigerant at -40 deg. C and 112.5 kPa, a medium
pressure (MP) outlet 4 for refrigerant at -21 deg. C and 234.5 kPa,
a high pressure (HP) outlet 5 for refrigerant at -6.6 deg. C and
384.8 kPa, and a high high pressure (HHP) outlet 6 for refrigerant
at 16.3 deg. C and 757.7 kPa.
[0033] This apparatus comprises a first compressor 10 having a
double suction configuration and a second compressor 20 having a
straight suction configuration. The first compressor 10 is received
in a single casing receiving two sets of impellers in a symmetric
arrangement such that a pair of main inlets 12 and 13 are defined
on either axial end of the casing, and an outlet 11 is defined in
an axially middle part of the casing. Each set of impellers may
include any number of impeller disks which are typically supported
by a common shaft.
[0034] The second compressor 20 is also received in a single
casing, and includes a plurality of impeller disks arranged in
series along the axial length thereof and typically supported by a
common shaft. The casing of the second compressor 20 defines an
outlet 21 at an axial end thereof, a first inlet 22 at the other
axial end thereof, and three more additional four inlets 23, 24 and
25 in axially intermediate positions thereof. The two compressors
10 and 20 are driven by an output shaft 31 of a common gas turbine
driver 30. It is also possible to use other drive sources such as
an electric motor or electric motors, instead of the gas turbine
driver.
[0035] The LP outlet of the refrigeration circuit 1 is connected to
the two main inlets 12 and 13 of the first compressor 10, and the
outlet 11 of the first compressor 10 is connected to the high high
high (HHHP) inlet 25 of the second compressor 20. The MP outlet 5
of the refrigeration circuit 1 is connected to the main inlet 22 of
the second compressor 20, and the HP outlet 6 and the HHP outlet 7
of the refrigeration circuit 1 are connected to the HP and HHP
inlets 23 and 24 of the second compressor 20, respectively. The
outlet 21 of the second compressor 20 is connected to the inlet 2
of the refrigeration circuit 1.
[0036] Alternatively, the HHHP inlet 25 may be omitted, and the
outlet 11 of the first compressor 10 may be directly connected to
the inlet 2 of the refrigeration circuit 1 as indicated by the
dotted line in FIG. 1a. It should be noted that connecting the
outlet of the first compressor 10 to an HHHP inlet of the second
compressor 20, instead of the inlet 2 of the refrigeration circuit
1 is an option also in other embodiments, wherever applicable,
which will be described hereinafter.
[0037] FIG. 1b shows a modification of the first embodiment which
is similar to the first embodiment except for the provision of an
economizer circuit in the outlet circuit that can be used for
reducing the flow rate of the refrigerant and hence the power
consumption of the gas turbine driver 30.
[0038] The outlet 21 of the second compressor 20 is connected to an
inlet of a desuperheater 41, instead of being connected directly to
the inlet 2 of the refrigeration circuit 1. The outlet of the
desuperheater 41 is connected to an economizer 44 via a condenser
42, an accumulator 43 and an adjustment valve 45, in that order.
The economizer 44 is also connected to a high high high (HHHP)
inlet 25 of the second compressor 20 (or the outlet 11 of the first
compressor 10), and to the inlet 2 of the refrigeration circuit
1.
[0039] In this embodiment, by suitably adjusting the adjustment
valve 45, the refrigerant flow can be adjusted depending on the
demand for the refrigerant. This economizer circuit can also be
optionally included in any of the following embodiments which will
be described hereinafter, where the second compressor 20 is
provided with a straight suction configuration.
[0040] FIG. 2a shows a second embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the second embodiment comprises a first compressor
10 having a double suction configuration and a second compressor 20
having a straight suction configuration. The first compressor 10
includes a pair of main inlets 12 and 13 defined on either axial
end of the casing, a pair of side inlets 14 and 15 and an outlet 11
defined in an axially middle part of the casing, preferably all in
a symmetric arrangement. Each set of impellers may include any
number of impeller disks which are typically supported by a common
shaft.
[0041] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof. The casing
of the second compressor 20 defines an outlet 21 at an axial end
thereof, a main inlet 22 at the other axial end thereof and a
single side inlet 23 in an axially intermediate position thereof.
The two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0042] The LP outlet 6 of the refrigeration circuit 1 is connected
to the main inlet 22 of the second compressor 20, and the MP outlet
5 of the refrigeration circuit 1 is connected to the two main
inlets 12 and 13 of the first compressor 10. The HP outlet 4 of the
refrigeration circuit 1 is connected to the two side inlets 14 and
15 of the first compressor 10, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the side inlet 23 of the
second compressor 20. The outlet 11 of the first compressor 10 and
the outlet 21 of the second compressor 20 are both connected to the
inlet 2 of the refrigeration circuit 1.
[0043] FIG. 2b shows a modification of the second embodiment which
is similar to the second embodiment except for the provision of an
economizer circuit in the outlet circuit that can be used for
reducing the flow rate of the refrigerant and hence the power
consumption of the gas turbine driver 30.
[0044] The outlet 21 of the second compressor 20 is connected to an
inlet of a desuperheater 41, instead of being connected directly to
the inlet 2 of the refrigeration circuit 1. The outlet of the
desuperheater 41 is connected to an economizer 44 via a condenser
42, an accumulator 43 and an adjustment valve 45, in that order.
The economizer 44 is also connected to a high high high (HHHP)
inlet 25 of the second compressor 20 and to the inlet 2 of the
refrigeration circuit 1. The outlet 11 of the first compressor 10
is connected to the high high high (HHHP) inlet 25 of the second
compressor 20.
[0045] In this embodiment, by suitably adjusting the adjustment
valve 45, the refrigerant flow can be adjusted depending on the
demand for the refrigerant. This economizer circuit can also be
optionally included in any of the following embodiments which will
be described hereinafter, where the second compressor 20 is
provided with a straight suction configuration.
[0046] FIG. 3 shows a third embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
In FIG. 3, the parts corresponding to those of the previous
embodiment without necessarily repeating the description of such
parts.
[0047] The apparatus of the third embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 having a straight suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing, a pair of side inlets 14 and 15 and
an outlet 11 defined in an axially middle part of the casing,
preferably all in a symmetric arrangement. Each set of impellers
may include any number of impeller disks which are typically
supported by a common shaft.
[0048] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof and
typically supported by a common shaft. The casing of the second
compressor 20 defines an outlet 21 at an axial end thereof, a main
inlet 22 at the other axial end thereof, and a single side inlet 23
in an axially intermediate position thereof. The two compressors 10
and 20 are driven by an output shaft 31 of a common gas turbine
driver 30.
[0049] The LP outlet 6 of the refrigeration circuit 1 is connected
to the two main inlets 12 and 13 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to the
two side inlets 14 and 15 of the first compressor 10. The HP outlet
4 of the refrigeration circuit 1 is connected to the main inlet 22
of the second compressor 20, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the side inlet 23 of the
second compressor 20. The outlet 21 of the first compressor 10 and
the outlet 21 of the second compressor 20 are both connected to the
inlet 2 of the refrigeration circuit 1.
[0050] FIG. 4 shows a fourth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
In FIG. 4 and other drawings showing different embodiments of the
present invention which are to be described hereinafter, the parts
corresponding to those of the preceding embodiments are denoted
with like numerals without necessarily repeating the description of
such parts.
[0051] The apparatus of the fourth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 also having a double suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing, a pair of side inlets 14 and 15 and
an outlet 11 defined in an axially middle part of the casing,
preferably all in a symmetric arrangement. Each set of impellers
may include any number of impeller disks which are typically
supported by a common shaft.
[0052] The second compressor 20 also includes a pair of main inlets
22 and 23 defined on either axial end of the casing, a pair of side
inlets 24 and 25 and an outlet 21 defined in an axially middle part
of the casing, preferably all in a symmetric arrangement. Each set
of impellers may include any number of impeller disks which are
typically supported by a common shaft. The two compressors 10 and
20 are driven by an output shaft 31 of a common gas turbine driver
30.
[0053] The LP outlet 6 of the refrigeration circuit 1 is connected
to the two main inlets 12 and 13 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to the
two side inlets 14 and 15 of the first compressor 10. The HP outlet
4 of the refrigeration circuit 1 is connected to the main inlets 22
and 23 of the second compressor 20, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the side inlets 24 and 25
of the second compressor 20. The outlet 11 of the first compressor
10 and the outlet 21 of the second compressor 20 are both connected
to the inlet 2 of the refrigeration circuit 1.
[0054] FIG. 5 shows a fifth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the fifth embodiment comprises a first compressor
10 having a double suction configuration and a second compressor 20
also having a double suction configuration. The first compressor 10
includes a pair of main inlets 12 and 13 defined on either axial
end of the casing, a pair of side inlets 14 and 15 and an outlet 11
defined in an axially middle part of the casing, preferably all in
a symmetric arrangement. Each set of impellers may include any
number of impeller disks which are typically supported by a common
shaft.
[0055] The second compressor 20 also includes a pair of main inlets
22 and 23 defined on either axial end of the casing, a pair of side
inlets 24 and 25 and an outlet 21 defined in an axially middle part
of the casing, preferably all in a symmetric arrangement. Each set
of impellers may include any number of impeller disks which are
typically supported by a common shaft. The two compressors 10 and
20 are driven by an output shaft 31 of a common gas turbine driver
30.
[0056] The LP outlet 6 of the refrigeration circuit 1 is connected
to the two main inlets 12 and 13 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to the
main inlets 22 and 23 of the second compressor 20. The HP outlet 4
of the refrigeration circuit 1 is connected to the side inlets 24
and 25 of the second compressor 20, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the two side inlets 14 and
15 of the first compressor 10. The outlet 11 of the first
compressor 10 and the outlet 21 of the second compressor 20 are
both connected to the inlet 2 of the refrigeration circuit 1.
[0057] FIG. 6 shows a sixth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the sixth embodiment comprises a first compressor
10 having a double suction configuration and a second compressor 20
also having a double suction configuration. The first compressor 10
includes a pair of main inlets 12 and 13 defined on either axial
end of the casing, a pair of side inlets 14 and 15 and an outlet 11
defined in an axially middle part of the casing, preferably all in
a symmetric arrangement. Each set of impellers may include any
number of impeller disks which are typically supported by a common
shaft.
[0058] The second compressor 20 also includes a pair of main inlets
22 and 23 defined on either axial end of the casing, a pair of side
inlets 24 and 25 and an outlet 21 defined in an axially middle part
of the casing, preferably all in a symmetric arrangement. Each set
of impellers may include any number of impeller disks which are
typically supported by a common shaft. The two compressors 10 and
20 are driven by an output shaft 31 of a common gas turbine driver
30.
[0059] The LP outlet 6 of the refrigeration circuit 1 is connected
to the two main inlets 12 and 13 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to the
main inlets 22 and 23 of the second compressor 20. The HP outlet 4
of the refrigeration circuit 1 is connected to the two side inlets
14 and 15 of the first compressor 10, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the side inlets 24 and 25
of the second compressor 20. The outlet 11 of the first compressor
10 and the outlet 21 of the second compressor 20 are both connected
to the inlet 2 of the refrigeration circuit 1.
[0060] FIG. 7 shows a seventh embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the seventh embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 having a straight suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing, a pair of side inlets 14 and 15,
and an outlet 11 defined in an axially middle part of the casing,
preferably all in a symmetric arrangement. Each set of impellers
may include any number of impeller disks which are typically
supported by a common shaft.
[0061] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof. The casing
of the second compressor 20 defines an outlet 21 at an axial end
thereof, a main inlet 22 at the other axial end thereof and a
single side inlet 23 in an axially intermediate position thereof.
The two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0062] The LP outlet 6 of the refrigeration circuit 1 is connected
to the two main inlets 12 and 13 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to the
main inlet 22 of the second compressor 20, and the HP outlet 4 of
the refrigeration circuit 1 is connected to the two side inlets 14
and 15 of the first compressor 10, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the side inlet 23 of the
second compressor 20. The outlet 11 of the first compressor 10 and
the outlet 21 of the second compressor 20 are both connected to the
inlet 2 of the refrigeration circuit 1.
[0063] FIG. 8 shows an eighth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the eighth embodiment comprises a first compressor
10 having a double suction configuration and a second compressor 20
having a straight suction configuration. The first compressor 10
includes a pair of main inlets 12 and 13 defined on either axial
end of the casing, a pair of side inlets 14 and 15 and an outlet 11
defined in an axially middle part of the casing, preferably all in
a symmetric arrangement. Each set of impellers may include any
number of impeller disks which are typically supported by a common
shaft.
[0064] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof. The casing
of the second compressor 20 defines an outlet 21 at an axial end
thereof, a main inlet 22 at the other axial end thereof and a
single side inlet 23 in an axially intermediate position thereof.
The two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0065] The LP outlet 6 of the refrigeration circuit 1 is connected
to the two main inlets 12 and 13 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to the
main inlet 22 of the second compressor 20. The HP outlet 4 of the
refrigeration circuit 1 is connected to the side inlet 23 of the
second compressor 20, and the HHP outlet 3 of the refrigeration
circuit 1 is connected to the two side inlets 14 and 15 of the
first compressor 10. The outlet 11 of the first compressor 10 and
the outlet 21 of the second compressor 20 are both connected to the
inlet 2 of the refrigeration circuit 1.
[0066] FIG. 9 shows a ninth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the ninth embodiment comprises a first compressor
10 having a double suction configuration and a second compressor 20
having a straight suction configuration. The first compressor 10
includes a pair of main inlets 12 and 13 defined on either axial
end of the casing and an outlet 11 defined in an axially middle
part of the casing, preferably all in a symmetric arrangement. Each
set of impellers may include any number of impeller disks which are
typically supported by a common shaft.
[0067] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof. The casing
of the second compressor 20 defines an outlet 21 at an axial end
thereof, a main inlet 22 at the other axial end thereof, and a pair
of side inlets 23 and 24 in axially intermediate positions thereof.
The two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0068] The LP outlet 6 of the refrigeration circuit 1 is connected
to the main inlet 22 of the second compressor 20, and the MP outlet
5 of the refrigeration circuit 1 is connected to the two main
inlets 12 and 13 of the first compressor 10. The HP outlet 4 of the
refrigeration circuit 1 is connected to the one of the side inlets
23 (lower pressure side) of the second compressor 20, and the HHP
outlet 3 of the refrigeration circuit 1 is connected to the other
side inlet 24 (higher pressure side) of the second compressor 20.
The outlet 11 of the first compressor 10 and the outlet 21 of the
second compressor 20 are both connected to the inlet 2 of the
refrigeration circuit 1.
[0069] FIG. 10 shows a tenth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the tenth embodiment comprises a first compressor
10 having a double suction configuration and a second compressor 20
having a straight suction configuration. The first compressor 10
includes a pair of main inlets 12 and 13 defined on either axial
end of the casing and an outlet 11 defined in an axially middle
part of the casing, preferably all in a symmetric arrangement. Each
set of impellers may include any number of impeller disks which are
typically supported by a common shaft.
[0070] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof. The casing
of the second compressor 20 defines an outlet 21 at an axial end
thereof, a main inlet 22 at the other axial end thereof and a pair
of side inlets 23 and 24 in axially intermediate positions thereof.
The two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0071] The LP outlet 6 of the refrigeration circuit 1 is connected
to the main inlet 22 of the second compressor 20, and the MP outlet
5 of the refrigeration circuit 1 is connected to one of the side
inlets 23 (lower pressure side) of the second compressor 20. The HP
outlet 4 of the refrigeration circuit 1 is connected to the two
main inlets 12 and 13 of the first compressor 10, and the HHP
outlet 3 of the refrigeration circuit 1 is connected to the other
side inlet 24 (higher pressure side) of the second compressor 20.
The outlet 11 of the first compressor 10 and the outlet 21 of the
second compressor 20 are both connected to the inlet 2 of the
refrigeration circuit 1.
[0072] FIG. 11 shows an eleventh embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the eleventh embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 having a straight suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0073] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof. The casing
of the second compressor 20 defines an outlet 21 at an axial end
thereof, a main inlet 22 at the other axial end thereof and a
single side inlet 23 in an axially intermediate position thereof.
The two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0074] The LP outlet 6 of the refrigeration circuit 1 is connected
to one of the main inlets 12 of the first compressor 10, and the MP
outlet 4 of the refrigeration circuit 1 is connected to the other
main inlet 13 of the first compressor 10. The HP outlet 4 of the
refrigeration circuit 1 is connected to the main inlet 22 of the
second compressor 20, and the HHP outlet 3 of the refrigeration
circuit 1 is connected to the side inlet 23 of the second
compressor 20. The outlet 11 of the first compressor 10 and the
outlet 21 of the second compressor 20 are both connected to the
inlet 2 of the refrigeration circuit 1.
[0075] FIG. 12 shows a twelfth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the twelfth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 also having a double suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0076] The second compressor 20 also includes a pair of main inlets
22 and 23 defined on either axial end of the casing, a pair of side
inlets 24 and 25 and an outlet 21 defined in an axially middle part
of the casing. In this case, the two parts of the dual suction
configuration of the second compressor 20 are preferably symmetric
to each other. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft. The
two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0077] The LP outlet 6 of the refrigeration circuit 1 is connected
to one of the two main inlets 12 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to the
other main inlet 13 of the first compressor. The HP outlet 4 of the
refrigeration circuit 1 is connected to the main inlets 22 and 23
of the second compressor 20, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the two side inlets 24 and
25 of the second compressor 20. The outlet 11 of the first
compressor 10 and the outlet 21 of the second compressor 20 are
both connected to the inlet 2 of the refrigeration circuit 1.
[0078] FIG. 13 shows a thirteenth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the thirteenth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 also having a double suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0079] The second compressor 20 also includes a pair of main inlets
22 and 23 defined on either axial end of the casing and an outlet
21 defined in an axially middle part of the casing. In this case
also, the two parts of the dual suction configuration of the first
compressor 10 may be either symmetric or asymmetric depending on
different design considerations. Each set of impellers may include
any number of impeller disks which are typically supported by a
common shaft. The two compressors 10 and 20 are driven by an output
shaft 31 of a common gas turbine driver 30.
[0080] The LP outlet 6 of the refrigeration circuit 1 is connected
to one of the two main inlets 12 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to the
other main inlet 12 of the first compressor 10. The HP outlet 4 of
the refrigeration circuit 1 is connected to one of the two main
inlets 22 of the first compressor 20, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the other main inlet 23 of
the second compressor 20. The outlet 11 of the first compressor 10
and the outlet 21 of the second compressor 20 are both connected to
the inlet 2 of the refrigeration circuit 1.
[0081] FIG. 14 shows a fourteenth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the fourteenth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 having a straight suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0082] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof. The casing
of the second compressor 20 defines an outlet 21 at an axial end
thereof, a main inlet 22 at the other axial end thereof and a
single side inlet 23 in an axially intermediate position thereof.
The two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0083] The LP outlet 6 of the refrigeration circuit 1 is connected
to the main inlet 22 of the second compressor 20, and the MP outlet
4 of the refrigeration circuit 1 is connected to one of the main
inlets 12 of the first compressor 10. The HP outlet 4 of the
refrigeration circuit 1 is connected to the other main inlet 13 of
the first compressor 10, and the HHP outlet 3 of the refrigeration
circuit 1 is connected to the side inlet 23 of the second
compressor 20. The outlet 11 of the first compressor and the outlet
21 of the second compressor 20 are both connected to the inlet 2 of
the refrigeration circuit 1.
[0084] FIG. 15 shows a fifteenth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the fifteenth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 also having a double suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0085] The second compressor 20 also includes a pair of main inlets
22 and 23 defined on either axial end of the casing, a pair of side
inlets 24 and 25, and an outlet 21 defined in an axially middle
part of the casing. In this case, the two parts of the dual suction
configuration of the second compressor 20 are preferably symmetric
to each other. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft. The
two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0086] The LP outlet 6 of the refrigeration circuit 1 is connected
to the two main inlets 22 and 23 of the second compressor 20, and
the MP outlet 5 of the refrigeration circuit 1 is connected to one
of the main inlet 12 of the first compressor. The HP outlet 4 of
the refrigeration circuit 1 is connected to the other main inlet 13
of the first compressor 10, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the two side inlets 24 and
25 of the second compressor 20. The outlet 11 of the first
compressor 10 and the outlet 21 of the second compressor 20 are
both connected to the inlet 2 of the refrigeration circuit 1.
[0087] FIG. 16 shows a sixteenth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the sixteenth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 having a straight suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0088] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof. The casing
of the second compressor 20 defines an outlet 21 at an axial end
thereof, a main inlet 22 at the other axial end thereof and a
single side inlet 23 in an axially intermediate position thereof.
The two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0089] The LP outlet 6 of the refrigeration circuit 1 is connected
to one of the main inlets 12 of the first compressor 10, and the MP
outlet 4 of the refrigeration circuit 1 is connected to the main
inlet 22 of the second compressor 20. The HP outlet 4 of the
refrigeration circuit 1 is connected to the side inlet 23 of the
second compressor 20, and the HHP outlet 3 of the refrigeration
circuit 1 is connected to the other main inlet 13 of the first
compressor 10. The outlet 11 of the first compressor 10 and the
outlet 21 of the second compressor 20 are both connected to the
inlet 2 of the refrigeration circuit 1.
[0090] FIG. 17 shows a seventeenth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the seventeenth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 also having a double suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0091] The second compressor 20 also includes a pair of main inlets
22 and 23 defined on either axial end of the casing, a pair of side
inlets 24 and 25 and an outlet 21 defined in an axially middle part
of the casing. In this case, the two parts of the dual suction
configuration of the second compressor 20 are preferably symmetric
to each other. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft. The
two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0092] The LP outlet 6 of the refrigeration circuit 1 is connected
to one of the two main inlets 12 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to the
main inlets 22 and 23 of the second compressor 20. The HP outlet 4
of the refrigeration circuit 1 is connected to the two side inlets
24 and 25 of the second compressor 20, and the HHP outlet 3 of the
refrigeration circuit 1 is connected to the other main inlet 13 of
the first compressor 10. The outlet 11 of the first compressor 10
and the outlet 21 of the second compressor 20 are both connected to
the inlet 2 of the refrigeration circuit 1.
[0093] FIG. 18 shows an eighteenth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the eighteenth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 also having a double suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0094] The second compressor 20 also includes a pair of main inlets
22 and 23 defined on either axial end of the casing and an outlet
21 defined in an axially middle part of the casing. In this case,
the two parts of the dual suction configuration of the first
compressor 10 may be either symmetric or asymmetric depending on
different design considerations. Each set of impellers may include
any number of impeller disks which are typically supported by a
common shaft. The two compressors 10 and 20 are driven by an output
shaft 31 of a common gas turbine driver 30.
[0095] The LP outlet 6 of the refrigeration circuit 1 is connected
to one of the two main inlets 12 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to one
of the two main inlets 22 of the second compressor 20. The HP
outlet 4 of the refrigeration circuit 1 is connected to the other
main inlet 23 of the second compressor 20, and the HHP outlet 3 of
the refrigeration circuit 1 is connected to the other main inlet 12
of the first compressor 10. The outlet 11 of the first compressor
10 is connected to the inlet 2 of the refrigeration circuit 1.
Likewise, the outlet 21 of the second compressor 120 is connected
to the inlet 2 of the refrigeration circuit 1.
[0096] FIG. 19 shows a nineteenth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the nineteenth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 having a straight suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0097] The second compressor 20 includes a plurality of impeller
disks arranged in series along the axial length thereof. The casing
of the second compressor 20 defines an outlet 21 at an axial end
thereof, a main inlet 22 at the other axial end thereof and a
single side inlet 23 in an axially intermediate position thereof.
The two compressors 10 and 20 are driven by an output shaft 31 of a
common gas turbine driver 30.
[0098] The LP outlet 6 of the refrigeration circuit 1 is connected
to one of the main inlets 12 of the first compressor 10, and the MP
outlet 4 of the refrigeration circuit 1 is connected to the main
inlet 22 of the second compressor 20. The HP outlet 4 of the
refrigeration circuit 1 is connected to the other main inlet 13 of
the first compressor 10, and the HHP outlet 3 of the refrigeration
circuit 1 is connected to the side inlet 23 of the second
compressor 20. The outlet 11 of the first compressor 10 and the
outlet 21 of the second compressor 20 are both connected to the
inlet 2 of the refrigeration circuit 1.
[0099] FIG. 20 shows a twentieth embodiment of the apparatus for
compressing gaseous refrigerant according to the present invention.
The apparatus of the twentieth embodiment comprises a first
compressor 10 having a double suction configuration and a second
compressor 20 also having a double suction configuration. The first
compressor 10 includes a pair of main inlets 12 and 13 defined on
either axial end of the casing and an outlet 11 defined in an
axially middle part of the casing. In this case, the two parts of
the dual suction configuration of the first compressor 10 may be
either symmetric or asymmetric depending on different design
considerations. Each set of impellers may include any number of
impeller disks which are typically supported by a common shaft.
[0100] The second compressor 20 also includes a pair of main inlets
22 and 23 defined on either axial end of the casing and an outlet
21 defined in an axially middle part of the casing. In this case
also, the two parts of the dual suction configuration of the first
compressor 10 may be either symmetric or asymmetric depending on
different design considerations. Each set of impellers may include
any number of impeller disks which are typically supported by a
common shaft. The two compressors 10 and 20 are driven by an output
shaft 31 of a common gas turbine driver 30.
[0101] The LP outlet 6 of the refrigeration circuit 1 is connected
to one of the two main inlets 12 of the first compressor 10, and
the MP outlet 5 of the refrigeration circuit 1 is connected to one
of the two main inlets 22 of the second compressor 20. The HP
outlet 4 of the refrigeration circuit 1 is connected to the other
main inlet 12 of the first compressor 10, and the HHP outlet 3 of
the refrigeration circuit 1 is connected to the other main inlet 23
of the second compressor 20. The outlet 11 of the first compressor
10 and the outlet 21 of the second compressor 20 are both connected
to the inlet 2 of the refrigeration circuit 1.
[0102] The present invention can be implemented in a number of
different ways as discussed above. In the foregoing embodiments,
the refrigeration circuit 1 included four outlets LP, MP, HP and
HHP which are denoted with numerals 6, 5, 4, 3 and 2, respectively.
Using notations A, D and S to denote "asymmetric double suction
configuration", "symmetric double suction configuration" and
"straight suction configuration" in combination with the associated
outlets 6, 5, 4, 3 and 2 of the refrigeration circuit 1, each of
the illustrated embodiments can be designated by the following
notations.
TABLE-US-00001 Embodiment Drawing Notation 1 FIGS. 1a and 1b
D6-S543 2 FIGS. 2a and 2b D54-S63 3 FIG. 3 D65-S43 4 FIG. 4 D65-D43
5 FIG. 5 D63-D54 6 FIG. 6 D64-D53 7 FIG. 7 D64-S53 8 FIG. 8 D63-S54
9 FIG. 9 D5-S643 10 FIG. 10 D4-S653 11 FIG. 11 A65-S43 12 FIG. 12
A65-D43 13 FIG. 13 A65-A43 14 FIG. 14 A54-S63 15 FIG. 15 A54-D63 16
FIG. 16 A63-S54 17 FIG. 17 A63-D54 18 FIG. 18 A63-A54 19 FIG. 19
A64-S53 20 FIG. 20 A64-A53
[0103] These notations are helpful in sorting out different
combinations of the compressors and the connections between the
compressors and the refrigeration circuit. Also, by using these
notations, it is also possible to consider different other
combinations of the compressors and the connections between the
compressors and the refrigeration circuit. Such other combinations
which are not covered by the foregoing embodiments are also part of
the present invention.
[0104] Although the present invention has been described in terms
of preferred embodiments thereof, it is obvious to a person skilled
in the art that various alterations and modifications are possible
without departing from the scope of the present invention which is
set forth in the appended claims. The contents of the prior art
references mentioned in this application are incorporated in this
application by reference.
* * * * *