U.S. patent application number 13/043686 was filed with the patent office on 2011-09-15 for turbo compressor and turbo refrigerator.
Invention is credited to Kazuaki KURIHARA, Noriyasu SUGITANI.
Application Number | 20110219812 13/043686 |
Document ID | / |
Family ID | 44558632 |
Filed Date | 2011-09-15 |
United States Patent
Application |
20110219812 |
Kind Code |
A1 |
KURIHARA; Kazuaki ; et
al. |
September 15, 2011 |
TURBO COMPRESSOR AND TURBO REFRIGERATOR
Abstract
Provided is a turbo compressor configured to compress a gas in
cooperation with a rotatable impeller and a diffuser formed around
the impeller and to discharge the compressed gas to the outside
thereof through a scroll chamber communicating with the diffuser,
the turbo compressor including: an impeller casing which is formed
by integrally molding a body portion surrounding the impeller and
forming a part of a the scroll chamber and a partition plate
provided at the rear surface side of the impeller; and a shroud
cover which is provided at the inside of the body portion to
surround the impeller and forming the scroll chamber in cooperation
with the body portion.
Inventors: |
KURIHARA; Kazuaki;
(Yokohama-shi, JP) ; SUGITANI; Noriyasu;
(Yokohama-shi, JP) |
Family ID: |
44558632 |
Appl. No.: |
13/043686 |
Filed: |
March 9, 2011 |
Current U.S.
Class: |
62/498 ;
415/204 |
Current CPC
Class: |
F25B 2400/13 20130101;
F05D 2220/40 20130101; F04D 25/02 20130101; F04D 29/4206 20130101;
F04D 25/0606 20130101; F01D 25/24 20130101; F01D 9/026 20130101;
F01D 15/005 20130101 |
Class at
Publication: |
62/498 ;
415/204 |
International
Class: |
F25B 1/00 20060101
F25B001/00; F01D 25/24 20060101 F01D025/24 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 9, 2010 |
JP |
P2010-051929 |
Claims
1. A turbo compressor configured to compress a gas in cooperation
with a rotatable impeller and a diffuser formed around the impeller
and to discharge the compressed gas the outside thereof through a
scroll chamber communicating with the diffuser, the turbo
compressor comprising: an impeller casing which is formed by
integrally molding a body portion surrounding the impeller and
forms a part of a the scroll chamber and a partition plate provided
at the rear surface side of the impeller; and a shroud cover which
is provided at the inside of the body portion to surround the
impeller and forming the scroll chamber in cooperation with the
body portion.
2. The turbo compressor according to claim 1, wherein the body
portion includes an inner peripheral surface contacting the shroud
cover, and wherein the shroud cover includes an annular fitting
frame portion fitted to the inner peripheral surface, an annular
shroud portion provided at the inside of the fitting frame portion
with a predetermined gap between the shroud portion and the
impeller, and a partition plate facing portion connecting the
fitting frame portion and the shroud portion to each other and
forming the diffuser in cooperation with the partition plate.
3. The turbo compressor according to claim 2, wherein at least a
part of the fitting frame is closely fitted to the inner peripheral
surface.
4. The turbo compressor according to claim 2, wherein the shroud
cover includes a plurality of reinforcement portions connecting the
fitting frame portion and the shroud portion to each other and
extending in the radial direction of the shroud portion.
5. The turbo compressor according to claim 1, further comprising:
an adjustment portion which adjusts the position of the shroud
cover with respect to the impeller casing in the rotation axis
direction of the impeller.
6. The turbo compressor according to claim 2, wherein the inner
peripheral surface of the scroll chamber is formed by a part of the
outer peripheral surface of the shroud cover and a part of the
inner peripheral surface of the body portion, and wherein the inner
peripheral surface portion of the scroll chamber formed by the
outer peripheral surface of the shroud cover is disposed closer to
the rotation shaft of the impeller than the inner peripheral
surface portion of the scroll chamber formed by the inner
peripheral surface of the casing body portion, and protrudes toward
the diffuser along the inner peripheral surface of the scroll
chamber.
7. The turbo compressor according to claim 1, wherein the shroud
cover further includes a suction port suctioning a gas toward the
impeller, and wherein the shroud cover is inserted from the suction
port into the body portion, and is fixed to the body portion at the
side of the suction port.
8. The turbo compressor according to claim 1, wherein the diffuser
is formed by the impeller casing and the shroud cover.
9. A turbo refrigerator comprising: a condenser which cools and
liquefies a compressed refrigerant; an evaporator which evaporates
the liquefied refrigerant and takes evaporation heat from a cooling
object to cool the cooling object; and a compressor which
compresses the refrigerant evaporated from the evaporator and
supplies the compressed refrigerant to the condenser, wherein the
turbo compressor according to claim 1 is used as the compressor.
Description
TECHNICAL FIELD
[0001] 1. Field of the Invention
[0002] The present invention relates to a turbo compressor and a
turbo refrigerator.
[0003] Priority is claimed on Japanese Patent Application No.
2010-51929, filed Mar. 9, 2010, the content of which is
incorporated herein by reference.
[0004] 2. Background Art
[0005] As a refrigerator cooling or freezing a cooling object such
as water, there is known a turbo refrigerator including a turbo
compressor compressing and discharging a refrigerant gas. In the
turbo compressor included in the turbo refrigerator, for example,
as shown in JP-A-2009-185713, the refrigerant gas is compressed in
cooperation with a rotatable impeller and a diffuser formed around
the impeller. Further, the turbo compressor discharges the
compressed refrigerant gas to the outside thereof through a scroll
chamber communicating with the diffuser. The diffuser and the
scroll chamber are formed by an impeller casing surrounding the
impeller.
[0006] The impeller casing is generally manufactured by sand mold
casting. In sand mold casting, sand for casting needs to be removed
after casting from the inside of the scroll chamber. In the
impeller casing, a casing body portion forming a part of the scroll
chamber is molded separately from a partition plate provided at the
rear surface side of the impeller and forming the scroll chamber in
cooperation with the body portion. Accordingly, the sand for
casting may be removed from the inside of the scroll chamber
through the installation position of the partition plate. However,
when the casing body portion and the partition plate are molded as
separate members, the number of components forming the impeller
casing increases, and a process of assembling the partition plate
to the casing body portion is required. As a result, there are
problems in that the effort and costs of manufacturing the impeller
casing increase and effort and costs of manufacturing the turbo
compressor and the turbo refrigerator increase.
[0007] The invention has been made in view of such circumstances,
and an object thereof is to provide a turbo compressor capable of
reducing manufacturing effort and manufacturing costs and a turbo
refrigerator having the turbo compressor.
SUMMARY OF THE INVENTION
[0008] In order to solve the above-described problems, the
invention adopts the following configurations.
[0009] According to an aspect of the invention, there is provided a
turbo compressor configured to compress a gas in cooperation with a
rotatable impeller and a diffuser formed around the impeller and
discharge the compressed gas to the outside thereof through a
scroll chamber communicating with the diffuser, the turbo
compressor including: an impeller casing which is formed by
integrally molding a body portion surrounding the impeller and
forming a part of a the scroll chamber and a partition plate
provided at the rear surface side of the impeller; and a shroud
cover which is provided at the inside of the body portion to
surround the impeller and forms the scroll chamber in cooperation
with the body portion.
[0010] The scroll chamber of the turbo compressor according to the
aspect of the invention is formed by the shroud cover and the body
portion of the impeller casing. Accordingly, when the impeller
casing is manufactured by sand mold casting, sand for casting
inside the scroll chamber may be removed through the installation
position of the shroud cover.
[0011] Further, the impeller casing of the aspect of the invention
is formed by integrally molding the body portion and the partition
plate. That is, the body portion and the partition plate are
integrally molded, and a process of assembling the partition plate
to the body portion is not necessary. As a result, the effort and
costs of manufacturing the impeller casing are reduced.
[0012] Further, in the turbo compressor according to the aspect of
the invention, the body portion may include an inner peripheral
surface contacting the shroud cover, and the shroud cover may
include an annular fitting frame portion fitted to the inner
peripheral surface, an annular shroud portion provided at the
inside of the fitting frame portion with a predetermined gap
between the shroud portion and the impeller, and a partition plate
facing portion connecting the fitting frame portion and the shroud
portion to each other and forming the diffuser in cooperation with
the partition plate.
[0013] Further, in the turbo compressor according to the aspect of
the invention, at least a part of the fitting frame may be closely
fitted to the inner peripheral surface.
[0014] Further, in the turbo compressor according to the aspect of
the invention, the shroud cover may include a plurality of
reinforcement portions connecting the fitting frame portion and the
shroud portion to each other and extending in the radial direction
of the shroud portion.
[0015] Further, the turbo compressor according to the aspect of the
invention may further include an adjustment portion which adjusts
the position of the shroud cover with respect to the impeller
casing in the rotation axis direction of the impeller.
[0016] Further, in the turbo compressor according to the aspect of
the invention, the inner peripheral surface of the scroll chamber
may be formed by a part of the outer peripheral surface of the
shroud cover and a part of the inner peripheral surface of the body
portion, and the inner peripheral surface portion of the scroll
chamber formed by the outer peripheral surface of the shroud cover
may be disposed closer to the rotation shaft of the impeller than
the inner peripheral surface portion of the scroll chamber formed
by the inner peripheral surface of the body portion, and protrude
toward the diffuser along the inner peripheral surface of the
scroll chamber.
[0017] Further, in the turbo compressor according to the aspect of
the invention, the shroud cover may further include a suction port
suctioning a gas toward the impeller, and the shroud cover may be
inserted from the suction port into the body portion, and be fixed
to the body portion at the side of the suction port.
[0018] Further, in the turbo compressor according to the aspect of
the invention, the diffuser may be formed by the impeller casing
and the shroud cover.
[0019] Further, according to another aspect of the invention, there
is provided a turbo refrigerator including: a condenser which cools
and liquefies a compressed refrigerant; an evaporator which
evaporates the liquefied refrigerant and takes evaporation heat
from a cooling object to cool the cooling object; and a compressor
which compresses the refrigerant evaporated from the evaporator and
supplies the compressed refrigerant to the condenser, wherein the
above-described turbo compressor may be used as the compressor.
[0020] According to the aspect of the invention, the following
advantages may be obtained.
[0021] According to the aspect of the invention, the effort and
costs of manufacturing the impeller casing may be reduced. As a
result, there is an advantage that the manufacturing effort and the
manufacturing costs may be reduced in the turbo compressor and the
turbo refrigerator having the turbo compressor.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] FIG. 1 is a block diagram illustrating a schematic
configuration of a turbo refrigerator of an embodiment of the
invention.
[0023] FIG. 2 is a horizontal cross-sectional view illustrating the
turbo compressor of the embodiment of the invention.
[0024] FIG. 3 is a horizontal cross-sectional view illustrating a
compressor unit of the embodiment of the invention.
[0025] FIG. 4 is a horizontal cross-sectional view illustrating a
first compression stage of the embodiment of the invention.
[0026] FIG. 5 is a front view illustrating a shroud cover of the
embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] Hereinafter, an exemplary embodiment of the invention will
be described by referring to FIGS. 1 to 5. In the respective
drawings used for the following description, the scales of the
respective members are appropriately changed so that the respective
members have recognizable sizes.
[0028] FIG. 1 is a block diagram illustrating a schematic
configuration of a turbo refrigerator S1 of the embodiment. The
turbo refrigerator S1 of the embodiment is installed at, for
example, a building, a factory, or the like in order to generate
air-conditioning cooling water. As shown in FIG. 1, the turbo
refrigerator S1 includes a condenser 1, an economizer 2, an
evaporator 3, and a turbo compressor 4.
[0029] A compressed refrigerant gas X1 as a compressed gas
refrigerant is supplied to the condenser 1, and the compressed
refrigerant gas X1 is cooled and liquefied at the condenser 1 so
that it becomes a refrigerant liquid X2. Further, as shown in FIG.
1, the condenser 1 is connected to the turbo compressor 4 through a
passageway R1 where the compressed refrigerant gas X1 flows, and is
connected to the economizer 2 through a passageway R2 where the
refrigerant liquid X2 flows. An expansion valve 5 is installed in
the passageway R2 so as to depressurize the refrigerant liquid
X2.
[0030] The economizer 2 temporarily stores the refrigerant liquid
X2 depressurized at the expansion valve 5. The economizer 2 is
connected to the evaporator 3 through a passageway R3 where the
refrigerant liquid X2 flows, and is connected to the turbo
compressor 4 through a passageway R4 where a gas phase component X3
of the refrigerant generated in the economizer 2 flows. An
expansion valve 6 is installed at the passageway R3 so as to
further depressurize the refrigerant liquid X2. Further, the
passageway R4 is connected to the turbo compressor 4 so as to
supply the gas phase component X3 to a second compression stage 22
described later and provided in the turbo compressor 4.
[0031] The evaporator 3 cools a cooling object by taking
evaporation heat from the cooling object such as water in a manner
such that the refrigerant liquid X2 evaporates. The evaporator 3 is
connected to the turbo compressor 4 through a passageway R5 where a
refrigerant gas X4 generated by the evaporation of the refrigerant
liquid X2 flows. The passageway R5 is connected to a first
compression stage 21 described later and provided in the turbo
compressor 4.
[0032] The turbo compressor 4 compresses the refrigerant gas X4 so
that it becomes the compressed refrigerant gas X1. As described
above, the turbo compressor 4 is connected to the condenser 1
through the passageway R1 where the compressed refrigerant gas X1
flows, and is connected to the evaporator 3 through the passageway
R5 where the refrigerant gas X4 flows.
[0033] In the turbo refrigerator S1 having the above-described
configuration, the compressed refrigerant gas X1 supplied to the
condenser 1 through the passageway R1 is cooled and liquefied by
the condenser 1 so that it becomes the refrigerant liquid X2.
[0034] The refrigerant liquid X2 is depressurized by the expansion
valve 5 when it is supplied to the economizer 2 through the
passageway R2, is temporarily stored in a depressurized state in
the economizer 2, and is further depressurized by the expansion
valve 6 when it is supplied to the evaporator 3 through the
passageway R3. That is, the twice depressurized refrigerant liquid
X2 is supplied to the evaporator 3.
[0035] The refrigerant liquid X2 supplied to the evaporator 3 is
evaporated by the evaporator 3 so that it becomes the refrigerant
gas X4, and is supplied to the turbo compressor 4 through the
passageway R5.
[0036] The refrigerant gas X4 supplied to the turbo compressor 4 is
compressed by the turbo compressor 4 so that it becomes the
compressed refrigerant gas X1, and is supplied again to the
condenser 1 through the passageway R1.
[0037] The gas phase component X3 of the refrigerant generated when
the refrigerant liquid X2 is stored in the economizer 2 is supplied
to the turbo compressor 4 through the passageway R4, and is
compressed together with the refrigerant gas X4 so that it is
supplied as the compressed refrigerant gas X1 to the condenser 1
through the passageway R1. In the turbo refrigerator S1, the
cooling object is cooled or frozen in a manner such that the
refrigerant liquid X2 takes evaporation heat from the cooling
object when evaporating from the evaporator 3.
[0038] Next, the turbo compressor 4 as a characteristic portion of
the embodiment will be more specifically described.
[0039] FIG. 2 is a horizontal cross-sectional view illustrating the
turbo compressor 4 of the embodiment. FIG. 3 is a horizontal
cross-sectional view illustrating a compressor unit 20 of the
embodiment. FIG. 4 is a horizontal cross-sectional view
illustrating the first compression stage 21 of the embodiment.
Further, FIG. 5 is a front view illustrating a shroud cover of the
embodiment. In FIG. 4, the description of an inlet guide vane 21f
and a drive mechanism 21g is omitted, and a first impeller 21a and
a rotation shaft 23 are represented by an imaginary line.
[0040] As shown in FIG. 2, the turbo compressor 4 of the embodiment
includes a motor unit 10, a compressor unit 20, and a gear unit
30.
[0041] The motor unit 10 includes a motor 12 which includes an
output shaft 11 and serves as a drive source driving the compressor
unit 20, and a motor casing 13 which surrounds the motor 12 and in
which the motor 12 is installed. The drive unit driving the
compressor unit 20 is not limited to the motor 12. For example, an
internal combustion engine may be used.
[0042] The output shaft 11 of the motor 12 is rotatably supported
by a first bearing 14 and a second bearing 15 fixed to the motor
casing 13.
[0043] The compressor unit 20 includes the first compression stage
21 which suctions and compresses the refrigerant gas X4 (refer to
FIG. 1), and the second compression stage 22 which further
compresses the refrigerant gas X4 compressed at the first
compression stage 21 and discharges it as the compressed
refrigerant gas X1 (refer to FIG. 1).
[0044] As shown in FIG. 3, the first compression stage 21 includes
a first impeller 21a (an impeller) which discharges the refrigerant
gas X4 in the radial direction by applying velocity energy to the
refrigerant gas X4 supplied in the thrust direction, a first
diffuser 21b (a diffuser) which compresses the refrigerant gas X4
by converting the velocity energy applied to the refrigerant gas X4
into pressure energy by the first impeller 21a, a first scroll
chamber 21c (a scroll chamber) which derives the refrigerant gas X4
compressed by the first diffuser 21b to the outside of the first
compression stage 21, and a suction port 21d which supplies the
refrigerant gas X4 to the first impeller 21a by suctioning the
refrigerant gas X4.
[0045] A part of the first diffuser 21b, the first scroll chamber
21c, and the suction port 21d is formed by a first impeller casing
21e surrounding the first impeller 21a. The first impeller casing
21e and the first scroll chamber 21c will be described later in
detail.
[0046] The rotation shaft 23 is provided inside the compressor unit
20 so as to extend across the first compression stage 21 and the
second compression stage 22. The first impeller 21a is fixed to the
rotation shaft 23, and the rotation shaft 23 rotates when a
rotation force is transmitted from the motor 12 (refer to FIG. 2)
to the rotation shaft 23.
[0047] Further, a plurality of inlet guide vanes 21f is provided in
the suction port 21d of the first compression stage 21 so as to
adjust the suction amount of the first compression stage 21. Each
inlet guide vane 21f is rotatably supported by the drive mechanism
21g fixed to the first impeller casing 21e so that an external area
in the stream direction of the refrigerant gas X4 is changeable.
Further, a vane drive unit 24 (refer to FIG. 2) is installed at the
outside of the first impeller casing 21e so that the vane drive
unit 24 is connected to the drive mechanism 21g and rotationally
drives each inlet guide vane 21f.
[0048] The second compression stage 22 includes a second impeller
22a which discharges the refrigerant gas X4 in the radial direction
by applying velocity energy to the refrigerant gas X4 compressed at
the first compression stage 21 and supplied in the thrust
direction, a second diffuser 22b which compresses and discharges
the compressed refrigerant gas X1 by converting the velocity energy
applied to the refrigerant gas X4 into pressure energy by the
second impeller 22a, a second scroll chamber 22c which derives the
compressed refrigerant gas X1 discharged from the second diffuser
22b to the outside of the second compression stage 22, and an
introduction scroll chamber 22d which guides the refrigerant gas X4
compressed by the first compression stage 21 to the second impeller
22a.
[0049] The second diffuser 22b, the second scroll chamber 22c, and
the introduction scroll chamber 22d are formed by a second impeller
casing 22e surrounding the second impeller 22a.
[0050] The second impeller 22a is fixed to the rotation shaft 23 so
that the rear surface thereof is coupled to the rear surface of the
first impeller 21a, and rotates when a rotation force is
transmitted from the motor 12 to the rotation shaft 23.
[0051] The second scroll chamber 22c is connected to the passageway
R1 (refer to FIG. 1) supplying the compressed refrigerant gas X1 to
the condenser 1, and supplies the compressed refrigerant gas X1
derived from the second compression stage 22 to the passageway
R1.
[0052] The first scroll chamber 21c of the first compression stage
21 and the introduction scroll chamber 22d of the second
compression stage 22 are connected to each other through an
external pipe (not shown) that is provided separately from the
first compression stage 21 and the second compression stage 22. The
refrigerant gas X4 compressed at the first compression stage 21 is
supplied to the second compression stage 22 through an external
pipe. The passageway R4 (refer to FIG. 1) is connected to the
external pipe, and the gas phase component X3 of the refrigerant
generated in the economizer 2 is configured to be supplied to the
second compression stage 22 through the external pipe.
[0053] The rotation shaft 23 is rotatably supported by a third
bearing 26 fixed to the second impeller casing 22e at a space 25
between the first compression stage 21 and the second compression
stage 22 and a fourth bearing 27 (refer to FIG. 2) fixed to the
gear unit 30 of the second impeller casing 22e. The rotation shaft
23 is provided with a labyrinth seal 23a that prevents the
refrigerant gas X4 from flowing from the introduction scroll
chamber 22d to the gear unit 30.
[0054] The configuration of the first impeller casing 21e and the
first scroll chamber 21c will be described in detail. As shown in
FIG. 4, a shroud cover 28 is provided in the first impeller casing
21e of the first compression stage 21.
[0055] The first impeller casing 21e is formed by integrally
molding a casing body portion 21h (a body portion) surrounding the
first impeller 21a and forming a part of the first scroll chamber
21c and a partition plate 21i provided at the rear surface side of
the first impeller 21a. The first impeller casing 21e is molded by
sand mold casting.
[0056] The casing body portion 21h is molded in an annular shape
surrounding the first impeller 21a, and includes an inner
peripheral surface 21j contacting the shroud cover 28. The inner
peripheral surface 21j is molded so as to have a circular shape
when seen from the side of the suction port 21d. The partition
plate 21i is molded in an annular plate shape, and is disposed
between the installed position of the first impeller 21a and the
space 25. The center portion of the partition plate 21i is provided
with a second labyrinth seal 29 which surrounds the rotation shaft
23 and prevents the refrigerant gas X4 from flowing from the first
impeller 21a to the space 25.
[0057] The first scroll chamber 21c is formed by the outer
peripheral surface of the shroud cover 28 and the inner peripheral
surface of the casing body portion 21h. More specifically, a part
of an outer peripheral surface of a fitting frame portion 28a of
the shroud cover 28 forms a part of the inner peripheral surface of
the first scroll chamber 21c (that is, in the inner peripheral
surface, a portion located at the inner diameter side of the first
compression stage 21). Further, a part of the inner peripheral
surface of the casing body portion 21h forms a part of the inner
peripheral surface of the first scroll chamber 21c (that is, in the
inner peripheral surface, a concave portion located at the outer
diameter side of the first compression stage 21). Further, the
fitting frame portion 28a is disposed closer to the rotation shaft
23 than a part of the inner peripheral surface of the first scroll
chamber 21c formed by the inner peripheral surface of the casing
body portion 21h, and protrudes toward the diffuser along the inner
peripheral surface of the first scroll chamber 21.
[0058] As described above, the shroud cover 28 is provided at the
inside of the casing body portion 21h so as to surround the first
impeller 21a, and forms the first scroll chamber 21c in cooperation
with the casing body portion 21h.
[0059] More specifically, the shroud cover 28 is formed by
integrally molding an annular fitting frame portion 28a which is
fitted to the inner peripheral surface 21j, an annular shroud
portion 28b which is provided at the inside of the fitting frame
portion 28a with a predetermined gap between the annular shroud
portion 28b and the first impeller 21a, and a partition plate
facing portion 28c which connects the fitting frame portion 28a and
the shroud portion 28b to each other and forms the first diffuser
21b in cooperation with the partition plate 21i.
[0060] The fitting frame portion 28a and the shroud portion 28b are
formed in a substantially cylindrical shape, and the partition
plate facing portion 28c is formed in an annular plate shape.
Accordingly, the weight of the shroud cover 28 may be
decreased.
[0061] A part of the outer peripheral surface of the fitting frame
portion 28a is closely fitted to the inner peripheral surface 21j.
Accordingly, the refrigerant gas X4 may be prevented and suppressed
from flowing from the first scroll chamber 21c through the fitting
portion between the fitting frame portion 28a and the inner
peripheral surface 21j. Further, a force necessary for fitting the
shroud cover 28 to the inner peripheral surface 21j may be
reduced.
[0062] The shroud cover 28 is fixed to the casing body portion 21h
at a fixation portion 28d (an adjustment portion). More
specifically, the shroud cover 28 is inserted from the suction port
21d (that is, the inner peripheral surface 21j) into the casing
body portion 21h, and is fixed from the suction port 21d to the
casing body portion 21h at the fixation portion 28d (the adjustment
portion). Further, the fitting frame portion 28a at the fixation
portion 28d is provided with a flange portion 28e that is used for
the connection to the casing body portion 21h. The flange portion
28e is formed in an annular frame shape that protrudes outward in
the radial direction from the end portion at the side of the
suction port 21d in the fitting frame portion 28a. The shroud cover
28 is fixed to the casing body portion 21h by using a plurality of
bolts 28f penetrating the flange portion 28e in the axis direction
of the rotation shaft 23.
[0063] Further, the fixation portion 28d is also used as an
adjustment portion that adjusts the position of the shroud cover 28
with respect to the first impeller casing 21e in the rotation axis
direction of the first impeller 21a. Specifically, when a
predetermined thin metal plate 29 (a so-called shim) is interposed
between the flange portion 28e and the casing body portion 21h, and
the thickness, the number or the like of the thin metal plates 29
is adjusted, the position of the shroud cover 28 may be adjusted in
the rotation axis direction of the first impeller 21a. Since the
position of the shroud cover 28 is adjusted, a gap between the
shroud portion 28b and the first impeller 21a may be optimally
adjusted, and the safe rotation of the first impeller 21a and the
high compression efficiency of the first compression stage 21 may
be ensured.
[0064] As shown in FIGS. 4 and 5, the shroud cover 28 includes a
plurality of ribs 28g (reinforcement portions) which connects the
fitting frame portion 28a and the shroud portion 28b to each other
and extends in the radial direction of the shroud portion 28b. The
shroud cover 28 is molded by, for example, casting, but the
surfaces of the shroud portion 28b and the partition plate facing
portion 28c at the side of the first impeller 21a are subjected to
machining (cutting or the like) after the casting. Since the
plurality of ribs 28g is provided, the strength of the shroud
portion 28b and the partition plate facing portion 28c improves. As
a result, vibration or the like may be prevented during the
machining.
[0065] The method of manufacturing the first impeller casing 21e
will be described.
[0066] As described above, the first impeller casing 21e is molded
by sand mold casting. In the sand mold casting, it is necessary to
remove sand for casting from the inside of the first scroll chamber
21c after the casting. Since the first scroll chamber 21c of the
embodiment is formed by the casing body portion 21h and the shroud
cover 28, sand for casing inside the first scroll chamber 21c may
be removed through the installation position of the shroud cover
28.
[0067] Further, the first impeller casing 21e of the embodiment is
formed by integrally molding the casing body portion 21h and the
partition plate 21i. That is, since the casing body portion 21h and
the partition plate 21i are integrally molded, it is not necessary
to provide a process of assembling the partition plate 21i to the
casing body portion 21h, and to reduce the effort and costs of
manufacturing the first impeller casing 21e.
[0068] A plurality of types of the shroud covers 28 may be provided
in accordance with the size, the shape, or the like of the first
impeller 21a.
[0069] In the turbo refrigerator S1 (refer to FIG. 1) including the
turbo compressor 4, in order to ensure a predetermined cooling
capability, the size or shape of the first impeller 21a, or the
width or the like of the first diffuser 21b may be changed. In the
embodiment, since a plurality of types of shroud covers 28 is
provided in accordance with the size or shape of the first impeller
21a, or the width or the like of the first diffuser 21b, a
predetermined cooling capability in the turbo refrigerator S1 may
be ensured.
[0070] Next, a configuration ensuring the predetermined cooling
capability will be described by referring to FIG. 2. The gear unit
30 is used to transmit the rotation force of the motor 12 to the
rotation shaft 23, and includes a spur gear 31 which is fixed to
the output shaft 11, a pinion gear 32 which is fixed to the
rotation shaft 23 and meshes with the spur gear 31, and a gear
casing 33 which accommodates the spur gear 31 and the pinion gear
32.
[0071] The spur gear 31 has an outer diameter larger than that of
the pinion gear 32, and transmits the rotation force of the motor
12 to the rotation shaft 23 so that the rpm of the rotation shaft
23 increases with respect to the rpm of the output shaft 11 by the
corporation between the spur gear 31 and the pinion gear 32. This
transmission method is not limited, and the diameters of the
plurality of gears may be set so that the rpm of the rotation shaft
23 is equal to or lower than the rpm of the output shaft 11.
[0072] In the gear casing 33, the motor casing 13 and the second
impeller casing 22e are separately molded, and are connected to
each other. The interior of the gear casing 33 is provided with an
accommodation space 33a that accommodates the spur gear 31 and the
pinion gear 32. Further, the gear casing 33 is provided with an oil
tank 34 that collects and stores a lubricant supplied to a sliding
portion of the turbo compressor 4.
[0073] Next, an operation of the turbo compressor 4 of the
embodiment will be described.
[0074] First, a rotation force of the motor 12 is transmitted to
the rotation shaft 23 through the spur gear 31 and the pinion gear
32, so that the first impeller 21a and the second impeller 22a of
the compressor unit 20 are rotationally driven.
[0075] When the first impeller 21a is rotationally driven, the
suction port 21d of the first compression stage 21 enters a
negative pressure state, the refrigerant gas X4 flows from the
passageway R5 to the first compression stage 21 through the suction
port 21d.
[0076] The refrigerant gas X4 flowing into the first compression
stage 21 flows into the first impeller 21a in the thrust direction,
and is discharged in the radial direction by applying velocity
energy thereto using the first impeller 21a.
[0077] The refrigerant gas X4 discharged from the first impeller
21a is compressed by converting the velocity energy into pressure
energy using the first diffuser 21b.
[0078] The refrigerant gas X4 discharged from the first diffuser
21b is derived to the outside of the first compression stage 21
through the first scroll chamber 21c. The refrigerant gas X4
derived to the outside of the first compression stage 21 is
supplied to the second compression stage 22 through an external
pipe (not shown).
[0079] The refrigerant gas X4 supplied to the second compression
stage 22 flows into the second impeller 22a in the thrust direction
through the introduction scroll chamber 22d, and is discharged in
the radial direction by applying velocity energy thereto using the
second impeller 22a.
[0080] The refrigerant gas X4 discharged from the second impeller
22a is further compressed into the compressed refrigerant gas X1 by
converting the velocity energy into pressure energy using the
second diffuser 22b.
[0081] The compressed refrigerant gas X1 discharged from the second
diffuser 22b is derived to the outside of the second compression
stage 22 through the second scroll chamber 22c. The compressed
refrigerant gas X1 derived to the outside of the second compression
stage 22 is supplied to the condenser 1 through the passageway
R1.
[0082] Finally, the operation of the turbo compressor 4 is
finished.
[0083] Therefore, according to the embodiment, the following
advantages may be obtained.
[0084] According to the embodiment, since the casing body portion
21h and the partition plate 21i are integrally molded, it is not
necessary to provide a process of assembling the partition plate
21i to the casing body portion 21h. As a result, the effort and
costs of manufacturing the first impeller casing 21e may be
reduced. Furthermore, there is an advantage in that the effort and
costs of manufacturing the turbo compressor 4 and the turbo
refrigerator S1 may be reduced.
[0085] While preferred embodiments of the invention have been
described and illustrated above, it should be understood that these
are exemplary of the invention and are not to be considered as
limiting. In the above-described examples, additions, omissions,
substitutions, and other modifications can be made without
departing from the spirit or scope of the present invention.
Accordingly, the invention is not to be considered as being limited
by the foregoing description, and is only limited by the scope of
the appended claims.
[0086] For example, the turbo compressor 4 of the above-described
embodiment is the double-stage compression type turbo compressor
including the first compression stage 21 and the second compression
stage 22, but the invention is not limited thereto. For example, a
single-stage compression type or a multiple-stage compression type
such as triple or more compression types may be adopted. Further,
the turbo compressor 4 of the above-described embodiment is used in
the turbo refrigerator S1, but may be used as, for example, a
supercharger supplying compressed air to an internal combustion
engine.
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