U.S. patent application number 10/832300 was filed with the patent office on 2005-01-27 for variable capacity scroll compressor.
This patent application is currently assigned to LG Electronics Inc.. Invention is credited to Kim, Cheol Hwan, Park, Hong Hee, Shin, Dong Koo.
Application Number | 20050019176 10/832300 |
Document ID | / |
Family ID | 34075002 |
Filed Date | 2005-01-27 |
United States Patent
Application |
20050019176 |
Kind Code |
A1 |
Shin, Dong Koo ; et
al. |
January 27, 2005 |
Variable capacity scroll compressor
Abstract
Disclosed is a variable capacity scroll compressor including an
intake passage connected to an intake chamber, an exhaust passage
connected to an exhaust chamber, a bypass port formed through a
wall defining a compression space, a bypass passage having a first
end connected to the bypass port and a second end connected to the
intake chamber that is in a low-pressure state, a check valve for
selectively connecting the bypass passage to the bypass port, and a
control valve for selectively applying one of low-pressure fluid
and high-pressure fluid in the exhaust passage to the check valve
to control the check valve to one of opening and closing
positions.
Inventors: |
Shin, Dong Koo;
(Gyeonggi-do, KR) ; Park, Hong Hee;
(Gyeongsangnam-do, KR) ; Kim, Cheol Hwan; (Seoul,
KR) |
Correspondence
Address: |
GREENBLUM & BERNSTEIN, P.L.C.
1950 ROLAND CLARKE PLACE
RESTON
VA
20191
US
|
Assignee: |
LG Electronics Inc.
Seoul
KR
|
Family ID: |
34075002 |
Appl. No.: |
10/832300 |
Filed: |
April 27, 2004 |
Current U.S.
Class: |
417/410.5 ;
417/902 |
Current CPC
Class: |
F04C 28/26 20130101;
F04C 18/0215 20130101; F04C 23/008 20130101 |
Class at
Publication: |
417/410.5 ;
417/902 |
International
Class: |
F04B 017/00; F04B
035/04 |
Foreign Application Data
Date |
Code |
Application Number |
Jul 26, 2003 |
KR |
51770/2003 |
Claims
What is claimed is:
1. A variable capacity scroll compressor comprising: a bypass port
formed through a wall defining a compression space; a bypass
passage having a first end connected to the bypass port and a
second end connected to an intake chamber that is in a low-pressure
state; a check valve for selectively connecting the bypass passage
to the bypass port; and a control valve for selectively applying
one of low-pressure fluid and high-pressure fluid in an exhaust
passage to the check valve to control the check valve to one of
opening and closing positions.
2. The variable capacity scroll compressor according to claim 1,
wherein the control valve is connected to (a) a low-pressure
passage connected to an intake passage, (b) a high-pressure passage
connected to the exhaust passage, and (c) a control passage
connected to the check valve, thereby controlling an application of
pressure.
3. The variable capacity scroll compressor according to claim 1,
wherein the check valve is a float valve.
4. The variable capacity scroll compressor according to claim 1,
wherein the bypass port is formed at a stationary scroll
member.
5. The variable capacity scroll compressor according to claim 1,
wherein the bypass port is formed at an orbiting scroll member.
6. The variable capacity scroll compressor according to claim 1,
wherein the control valve is a solenoid valve.
7. The variable capacity scroll compressor according to claim 1,
wherein the bypass port is formed on an opposite side of a
location, where a start point of the compression space is formed,
based on a center of a scroll member.
8. The variable capacity scroll compressor according to claim 1,
wherein the bypass port is formed at a location where the bypass
port can be closed by a rotational scroll wrap.
9. The variable capacity scroll compressor according to claim 1,
wherein the low-pressure fluid is supplied through an intake
passage of the compressor.
10. The variable capacity scroll compressor according to claim 1,
wherein the control valve is connected to (a) a high-pressure
passage connected to the exhaust passage and (b) a control passage
connected to the check valve, thereby controlling an application of
pressure applying.
11. The variable capacity scroll compressor according to claim 1,
wherein the control passage is formed penetrating a seal plate
dividing a low-pressure side from a high-pressure side.
12. A variable capacity scroll compressor comprising: a bypass port
formed on a compression path defined between first and second
scroll members; a check valve for controlling opening and closing
states of the bypass port; and a bypass controller for controlling
an opening/closing operation of the check valve using at least
pressure applied from an exhaust passage.
13. The variable capacity scroll compressor according to claim 1,
wherein the bypass controller comprises: a control valve for
selectively supplying one of fluid pressure of an intake passage
and fluid pressure of the exhaust pressure; and a control passage
having opposite ends respectively connected to the control valve
and the check valve to apply the fluid pressure supplied from the
control valve to the check valve.
14. The variable capacity scroll compressor according to claim 12,
wherein the bypass controller comprises: a control valve for
selectively supplying fluid pressure of the exhaust passage; and a
control passage having opposite ends respectively connected to the
control valve and the check valve to apply the fluid pressure
supplied from the control valve to the check valve.
15. The variable capacity scroll compressor according to claim 12,
wherein fluid being compressed is exhausted to an intake chamber
through the bypass port.
16. The variable capacity scroll compressor according to claim 12,
wherein the bypass port is designed to bypass fluid compressed in
at least one of two intake spaces.
17. The variable capacity scroll compressor according to claim 12,
wherein the bypass port is defined between an inner circumference
of a rotational scroll wrap formed on the first scroll member and
an outer circumference of a rotational scroll wrap formed on the
second scroll member.
18. The variable capacity scroll compressor according to claim 12,
wherein the check valve comprises a check ball that is designed to
freely move in a cavity by fluid pressure.
19. A variable capacity scroll compressor comprising: a bypass port
formed on a compression path defined between first and second
scroll members; a float valve for controlling opening and closing
states of the bypass port; and a bypass controller for controlling
an operation of the check valve by high-pressure fluid applied from
an exhaust passage.
20. A variable capacity scroll compressor according to claim 19,
wherein, in order to control the operation of the check valve,
low-pressure fluid may be further applied to the bypass controller
from an intake passage.
21. A variable capacity scroll compressor according to claim 19,
wherein the bypass port is formed at a location allowing for both
of symmetry and asymmetry operation modes of the scroll
compressor.
22. A variable capacity scroll compressor according to claim 19,
wherein the bypass port is formed on a sidewall defining a
compression space.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a scroll compressor, and
more particularly, to a variable capacity scroll compressor, which
is configured to vary a compression capacity according to a simple
operation of a system where the compressor is applied.
[0003] 2. Description of the Related Art
[0004] Generally, a cooling system is applied to an air conditioner
or a refrigerator to lower the temperature of an enclosed space by
absorbing and discharging heat using refrigerant circulating a
cooling cycle.
[0005] Such a cooling system is configured to perform a series of
cycles of compression, condensation, expansion and vaporization of
refrigerant. A scroll compressor is used to perform the compression
cycle among the series of cycles.
[0006] Since the scroll compressor is disclosed in a plurality of
published documents, the detailed description on the general
structure and operation will be omitted herein.
[0007] The reason why the compression capacity of a scroll
compressor should be varied will be described hereinafter.
[0008] A scroll compressor for a specific use is generally selected
by considering the most disadvantageous operation condition when
forecasting its use environment, for instance, the greatest
compression capacity-requested condition (i.e., a heating operation
of an air conditioner using heat pump).
[0009] However, it is general that the most disadvantageous
condition does not nearly occur in an actual operation. In an
actual operation of the compressor, a condition needing a small
compression capacity (ex. cooling operation of air conditioner) not
the most disadvantageous condition exists too.
[0010] Thus, when the compressor having a large compression
capacity is selected considering the worst condition, the
compressor is operated under the low-load condition during an
operation period of the high-compression ratio, thereby
deteriorating an overall operation efficiency of the system.
[0011] Therefore, in order to improve the overall operating
efficiency even under a normal operating condition and to accept
the operational condition under the most disadvantageous condition,
there is a need for a compressor that has a variable compression
capacity.
[0012] To vary the compression capacity of the scroll compressor, a
method for electrically controlling an RPM of the compressor has
been most widely used.
[0013] Such an electrical control method has an advantage of
effectively varying the compression capacity. However, additional
components, for instance, an inverter for accurately controlling
the RPM of a motor, are required. Furthermore, when the motor
rotates with a relatively high RPM, it is difficult to ensure a
reliability of frictional portions.
SUMMARY OF THE INVENTION
[0014] Accordingly, the present invention is directed to a variable
capacity scroll compressor that substantially obviates one or more
problems due to limitations and disadvantages of the related
art.
[0015] An object of the present invention is to provide a variable
capacity scroll compressor that can vary a compression capacity
using a bypass function in a state where a compressor motor rotates
at a constant RPM.
[0016] Another object of the present invention is to provide a
variable capacity scroll compressor that can vary a compression
capacity by operating a valve using either uncompressed
low-pressure fluid or compressed high-pressure fluid.
[0017] Additional advantages, objects, and features of the
invention will be set forth in part in the description which
follows and in part will become apparent to those having ordinary
skill in the art upon examination of the following or may be
learned from practice of the invention. The objectives and other
advantages of the invention may be realized and attained by the
structure particularly pointed out in the written description and
claims hereof as well as the appended drawings.
[0018] To achieve these objects and other advantages and in
accordance with the purpose of the invention, as embodied and
broadly described herein, there is provided a variable capacity
scroll compressor including: a bypass port formed through a wall
defining a compression space; a bypass passage having a first end
connected to the bypass port and a second end connected to an
intake chamber that is in a low-pressure state; a check valve for
selectively connecting the bypass passage to the bypass port; and a
control valve for selectively applying one of low-pressure fluid
and high-pressure fluid in an exhaust passage to the check valve to
control the check valve to one of opening and closing
positions.
[0019] In another aspect of the present invention, there is
provided a variable capacity scroll compressor including: a bypass
port formed on a compression path defined between first and second
scroll members; a check valve for controlling opening and closing
states of the bypass port; and a bypass controller for controlling
an opening/closing operation of the check valve using at least
pressure applied from an exhaust passage.
[0020] In still another aspect of the present invention, there is
provided a variable capacity scroll compressor including: a bypass
port formed on a compression path defined between first and second
scroll members; a float valve for controlling opening and closing
states of the bypass port; and a bypass controller for controlling
an operation of the check valve by high-pressure fluid applied from
an exhaust passage.
[0021] According to the present invention, the capacity variation
of the scroll compressor can be easily varied without adding
additional components.
[0022] The present invention has an advantage the inventive
compressor can be effectively used when it is employed to a system
where a capacity variation is required.
[0023] It is to be understood that both the foregoing general
description and the following detailed description of the present
invention are exemplary and explanatory and are intended to provide
further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] The accompanying drawings, which are included to provide a
further understanding of the invention and are incorporated in and
constitute a part of this application, illustrate embodiment(s) of
the invention and together with the description serve to explain
the principle of the invention. In the drawings:
[0025] FIG. 1 is a sectional view of a scroll compressor according
to a first embodiment of the present invention;
[0026] FIG. 2 is a bottom view of a stationary scroll member
depicted in FIG. 1;
[0027] FIG. 3 is an enlarged view of a portion "A"of FIG. 1, in
which a bypass port is closed;
[0028] FIG. 4 is a view conceptually illustrating a state of a
scroll member when a bypass port is closed;
[0029] FIG. 5 is an enlarged view of a portion "A" of FIG. 1, in
which a bypass port is opened;
[0030] FIG. 6 is a view conceptually illustrating a state of scroll
member when a bypass port is opened; and
[0031] FIG. 7 is a sectional view of a scroll compressor according
to a second embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0032] Reference will now be made in detail to the preferred
embodiments of the present invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers will be used throughout the drawings to
refer to the same or like parts.
[0033] FIG. 1 shows a sectional view of a scroll compressor
according to an embodiment of the present invention.
[0034] Referring to FIG. 1, the inventive scroll compressor
includes a conventional compressing part, a bypass part for varying
a compression capacity, and a bypass control part for controlling
the bypass part.
[0035] The conventional compressing part includes a seal case 11
for defining an enclosed chamber, a seal plate 12 disposed in the
seal case 11 to divide the sealed chamber into a low-pressure
intake chamber 13 and a high-pressure exhaust chamber 14, an intake
passage 22 connected to the intake chamber 13 to supply fluid to be
compressed to the intake chamber 13, an exhaust passage 23
connected to the exhaust chamber 14 to exhaust compressed fluid out
of the exhaust chamber 14, a stationary scroll member 15 fixed on
an inner circumference of the seal case 11, a driving shaft 19
extending from a motor (not shown) and having an eccentric upper
end, a orbiting scroll member 16 associated with the driving shaft
19, a stationary spiral wrap 17 formed on the stationary scroll
member 15, a rotational spiral wrap 18 defining the fluid
compressing path by surface-contacting the stationary spiral wrap
17, a bearing 21 for stably supporting the driving shaft 19, and a
central exhaust passage 26 formed through a central axis of the
stationary scroll member 15 to direct the compressed fluid to the
exhaust chamber 14.
[0036] The bypass part includes a bypass port 24 formed through a
portion of the stationary scroll member 15, a check valve 25 formed
on a rear side of the bypass port 24 to control the flowing
direction of the fluid, and a bypass passage 31 branched off from
the check valve 25 to allow the fluid exhausted through the bypass
port 24 to be directed to the intake chamber 13.
[0037] The bypass control part includes a control passage 30 for
forming control pressure for controlling an opening/closing
operation of the check valve 25 and a control valve 29 for allowing
the control pressure formed on the control passage 30 to be
selectively supplied from one of the low-pressure and high-pressure
passages 27 and 28. The control passage 30 is formed penetrating
the seal plate 12 to communicate with a compression space of the
conventional compressing part.
[0038] Particularly, the low-pressure passage 27 has a first end
connected to the control valve 29 and a second end connected to the
intake passage 22 so that low-pressure of the intake passage 22 can
be applied to the low-pressure passage 27. The high-pressure
passage 28 has a first end connected to the control valve 29 and a
second end connected to the exhaust passage 23 so that
high-pressure of the exhaust passage 23 can be applied to the
high-pressure passage 28.
[0039] Meanwhile, the check valve 25 may be formed of a float valve
having a floating member moving in a direction where pressure is
applied to change a passage connection state.
[0040] For example, as shown in the drawing, a cylindrical member
is disposed in a cylindrical housing, being movable in a direction
where low-pressure is applied.
[0041] Alternatively, a check ball may be movably disposed in a
housing so that a fluid passage hole can be opened or closed by the
check ball. That is, any types of valves that are designed to be
controlled by pressure can be employed to the present
invention.
[0042] In addition, the control valve 29 can be formed of a
solenoid valve controlled by a predetermined controller.
[0043] The operation of the above described variable capacity
scroll compressor will be described hereinafter.
[0044] When the driving shaft 19 is rotated by the motor (not
shown), the orbiting scroll member 16 associated with the driving
shaft 19 rotates. At this point, the stationary scroll member 15 is
in a fixed state.
[0045] When the orbiting scroll member 16 rotates, low-pressure
fluid stored in the intake chamber 13 is directed into a space
defined between the rotational spiral wrap 18 formed on the
orbiting scroll member 16 and the stationary spiral wrap 17 formed
on the stationary scroll member 15, and is then compressed in the
space.
[0046] The compressed fluid is directed into the exhaust chamber 14
through the central exhaust passage 26 formed through the central
axis of the stationary scroll member 15, and the high-pressure
fluid in the exhaust chamber 14 is exhausted through the exhaust
passage 23.
[0047] Meanwhile, when the check valve 25 is closed (when the check
valve 25 is moved downward in the drawing), the fluid cannot be
exhausted through the bypass port 24. However, when the check valve
25 is opened (when the check valve 25 is moved upward in the
drawing), the fluid is exhausted through the bypass port 24, and is
then bypassed into the intake chamber 13 through the bypass passage
31. Therefore, when the check valve 25 is opened, the compression
capacity is reduced.
[0048] To control the operation of the check valve 25, the bypass
control part further includes a control passage, one end of which
is connected to the check valve 25 to applied control pressure to
the check valve 25. The control valve 29 is formed on the other end
of the control passage 30. By the control valve 29, one of the
fluid pressures from the low-pressure and high-pressure passages 27
and 28 is selected and applied to the control passage 30.
[0049] Particularly, the low-pressure and high-pressure passages 27
and 28 are respectively connected to the intake and exhaust
passages 22 and 23 such that low-pressure fluid that is not
compressed in the conventional compressing part and high-pressure
fluid that is compressed in the conventional compressing part can
be respectively supplied to the low-pressure and high-pressure
passages 27 and 28. As a result, the control passage 30 is
selectively supplied with one of the low-pressure and high-pressure
fluids in the respective low-pressure and high-pressure passages 27
and 28.
[0050] Describing more in detail, when the high-pressure passage 28
is connected to the control passage 30 by the control valve moved
upward in FIG. 1, since the control passage 30 is supplied with the
high-pressure, the check valve 25 is closed by moving downward.
When the check valve 25 is closed, since the bypass port 24 is
closed, the fluid being compressed cannot be bypassed. As a result,
a relatively large amount of fluid can be compressed without any
compression capacity loss.
[0051] When the low-pressure passage 27 is connected to the control
passage 30 by the control valve moved downward FIG. 1, since the
low-pressure is applied to the control passage 30, the check valve
25 is opened by moving upward in FIG. 1. That is, pressure of fluid
being compressed by a mutual operation of the scroll members 15 and
16 is lower than that in the intake pressure 22, the check valve 25
that is the floating valve is opened.
[0052] In addition, when the check valve 25 is opened, since the
bypass port 24 is opened, the fluid being compressed is bypassed
into the intake chamber 13 through the bypass passage 31.
Therefore, the compression capacity is reduced as much as an amount
of fluid bypassed.
[0053] FIG. 2 shows a bottom view of the stationary scroll member
15 depicted in FIG. 1.
[0054] Referring to FIG. 2, the stationary spiral wrap 17 is formed
on the stationary scroll member 15, and the central exhaust passage
26 is formed through the central portion of the stationary spiral
wrap 17. The bypass port 24 is formed on the scroll member in a
compression space defined by the stationary spiral wrap 17, thereby
allowing the fluid being compressed to be bypassed.
[0055] FIGS. 3 and 5 show enlarged views of a portion "A" in FIG.
1, and FIGS. 4 and 6 show views conceptually illustrating a scroll
member according to opening and closing states of a bypass port.
FIGS. 3 and 4 show a state where the bypass port is closed, and
FIGS. 5 and 6 show a state where the bypass port is opened.
[0056] Referring first to FIG. 3, the bypass port 24 is formed at a
position between spaced parts of the spiral wrap 17, and is in a
closed state by the check valve 25. At this time, since
high-pressure is applied to the check valve 25 through the control
passage 30, the check valve 25 firmly closes the bypass port
24.
[0057] Referring to FIG. 4, when the bypass port 24 is closed, a
first intake volume 41 that is a compression space defined between
the stationary spiral wrap 17 and the orbiting spiral wrap 18 can
be formed from a start position where the stationary spiral wrap 17
meets the orbiting spiral wrap 18.
[0058] The intake volume will be described more in detail
hereinafter.
[0059] The intake volume defined between the stationary and
orbiting spiral wraps 17 and 18 contacting each other may include
two intake volumes.
[0060] One is a first intake space defined when an inner
circumference of the stationary spiral wrap 17 meets an outer
circumference of the orbiting spiral wrap 18. The first intake
space can be illustrated as the first intake volume 41 depicted in
FIG. 4.
[0061] The other is a second intake space (not shown) when an outer
circumference of the stationary spiral wrap 17 meets an inner
circumference of the orbiting spiral wrap 18. Although the second
intake space is not shown in the drawing, it can be assumed that
the second intake space can be formed by the orbiting operation of
the orbiting spiral wrap 18.
[0062] A start point of the first intake space is defined on a
location indicated by the reference character SC1 (Compress Start
1), and a start point of the second intake space is defined on a
location indicated by the reference character SC2 (Compress Start
2. Since the start points SC1 and SC2 are not symmetrically
located, this can be called an asymmetry operation mode. That is,
when the scroll member is divided into half-and half based on the
central portion of the scroll member and both the start points SC1
and SC2 are sided to one half, this can be called the asymmetric
operation mode.
[0063] Referring to FIG. 5, when the bypass port 24 is opened by
the check valve 25 moved upward, since the control passage 30 is
supplied with the low-pressure as described above, the check valve
25 is opened to allow the fluid being compressed to be bypassed
into the intake chamber 13 through the bypass port 24 and the pass
passage 31.
[0064] Referring to FIG. 6, in a state where the bypass port 24 is
opened, a start point of a second intake volume 42 defined between
the stationary spiral wrap 42 and the rotational spiral wrap 18 is
not defined on a location where the stationary spiral wrap 17
firstly meets the rotational spiral wrap 18. That is, it can be
noted that a start point of the second intake volume 42 is defined
on a location passed over the location where the bypass port 24 is
formed.
[0065] The intake volume formed when the bypass port is opened will
be described more in detail.
[0066] In this case, the intake volume defined between the
stationary and rotational spiral wraps 17 and 18 contacting each
other may be also divided into first and second volumes.
[0067] The first volume is a first intake space defined when an
inner circumference of the stationary spiral wrap 17 meets an outer
circumference of the rotational spiral wrap 18. The first intake
space can be illustrated as the second intake volume 42 depicted in
FIG. 6.
[0068] The second volume is a second intake space (not shown) when
an outer circumference of the stationary spiral wrap 17 meets an
inner circumference of the rotational spiral wrap 18. Although the
second intake space is not shown in the drawing, it can be assumed
that the second intake space can be formed by the rotational
operation of the rotational spiral wrap 18.
[0069] In addition, since the bypass port 24 is formed near the
inner circumference of the stationary spiral wrap, it does not
interfere with the formation of the second intake space. However,
the second intake space is formed only when the bypass port 24 is
closed by a thickness of the rotational spiral wrap 18. That is,
although the second intake space is not affected by the presence of
the bypass port 24 by the rotational spiral wrap 18, an amount of
fluid that is bypassed can be further varied in accordance with a
thickness of the rotational spiral wrap 18 and a relative location
of the bypass port 24 formed in the compression space. When the
bypass port 24 is formed on a sidewall defining the compression
space, the second intake space can be formed regardless of the
thickness of the rotational spiral wrap.
[0070] In the beginning of the compression, a start point of the
first intake space is defined on a location indicated by the
reference character CS1, and a start point of the second intake
space is formed on a location indicated by the reference character
CS2. That is, the start points CS1 and CS2 are symmetrically
located based on the centers of the scroll members 15 and 16. This
can be called a symmetry operation mode.
[0071] Meanwhile, in order to realize the perfect symmetry
operation mode, the bypass port 24 is formed on an opposite side of
a spiral start point of the stationary spiral wrap 17 based on the
center of the stationary scroll member 15.
[0072] When comparing the first intake volume 41 depicted in FIG. 4
with the second intake volume 42 depicted in FIG. 6, it can be
noted that they are different from each other.
[0073] The first intake volume 41 is greater than the second intake
volume 42. This shows that, in the asymmetry operation mode, much
more fluid can be compressed. However, the second intake space
formed in the asymmetry operation mode may be identical to that
formed in the symmetry operation mode.
[0074] That is, since the volume of the intake space is varied
according to a state (an open/close state) of the bypass port 24,
the compression capacities defined by the first intake volume 41,
formed when the bypass port is closed, and by the second intake
volume 42, formed when the bypass port is opened, are difference
from each other.
[0075] According to a series of tests, it was noted that, when the
bypass port is formed on the location proposed in the drawing, the
compression capacity obtained by performing the compression using a
possible maximum volume tolerance (whole load) in a state where the
bypass port 24 is closed is increased by 18% as compared with that
obtained by performing the compression using a part of the
compressible capacity (a partial load) in a state where the bypass
port 24 is opened.
[0076] That is, the operation of the scroll compressor is changed
into one of the symmetry and asymmetry operation modes according to
a variety of factors such as the opening/closing state of the
bypass port 24, the opening/closing state of the check valve 25,
and the control state of the control valve 29. In addition, the
intake volume of the scroll compressor is increased or decreased in
accordance with the opening/closing state of the bypass port 24,
thereby varying the compression capacity of the scroll
compressor.
[0077] For example, when the control valve 29 is controlled such
that the high-pressure passage 28 is connected to the control
passage 30, the check valve 25 moves downward in the drawing, and
the bypass port 24 is closed. The start points of the first and
second intake spaces are asymmetrically located to operate the
scroll compressor in the asymmetry operation mode, thereby
increasing the compression capacity. Therefore, this asymmetry
operation mode is suitable for, for example, a heating mode of an
air conditioner where a relatively large amount of compression
capacity is required.
[0078] When the control valve 29 is controlled such that the
low-pressure passage 27 is connected to the control passage 30, the
check valve 25 moves upward in the drawing, and the bypass port 24
is opened. The start points of the first and second intake spaces
are symmetrically located to operate the scroll compressor in the
symmetry operation mode, thereby reducing the compression capacity.
Therefore, this symmetry operation mode is suitable for, for
example, a cooling mode of the air conditioner where a relatively
amount of compression capacity is required.
[0079] The application of the compressor of the present invention
is not limited to the air conditioner that is used only for a
description example. That is, the inventive compressor can be
applied to any systems requiring a variable compression
capacity.
[0080] FIG. 7 shows a scroll compressor according to a second
embodiment of the present invention.
[0081] As shown in the drawing, the scroll compressor of this
embodiment is identical to that of the first embodiment except for
a connection structure around the control valve.
[0082] In detail, a control passage 52, a control valve 53, and a
high-pressure passage 51 are same as those in the first embodiment.
However, the low-pressure passage 27 that is selectively connected
to the control passage by the control valve in the first embodiment
is not formed in this embodiment.
[0083] When the low-pressure passage 27 is not formed, the
low-pressure of the intake passage 22 is not applied to the control
passage 52 even when the control valve 53 moves downward in the
drawing.
[0084] At this point, since internal pressure of the control
passage 52 is lower than medium-pressure of fluid being compressed
in the conventional compressing part, the check valve 25 can be
opened. That is, when the high-pressure that has been supplied via
the high-pressure passage 51 and the control valve 53 is not
supplied, the high-pressure fluid in the control passage 52 is
exhausted through the check valve 25 to realize a pressure balance
based on the check valve 25. Therefore, when the pressure balance
is realized in the control passage 52 and the compression space is
formed in a high-pressure environment by the operation of the
scroll compressor, the check valve 25 that is in the pressure
balance state is opened by the fluid being compressed.
[0085] As described above, by simply controlling the control valve,
it is possible to conveniently allow the fluid being compressed to
be bypassed. Particularly, the mainspring of the control of the
bypass port is to selectively use low-pressure formed by fluid that
is not sucked into the conventional compressing part and
high-pressure formed by fluid compressed by the conventional
compressing part.
[0086] Therefore, the structure of the scroll compressor can be
more simplified, reducing the manufacturing costs.
[0087] The variable capacity scroll compressor according to the
present invention has an advantage in that it is possible to vary
the compression capacity in multi-stages using a bypass function,
which can be realized by a simple structure, without varying the
RPM of the compression motor.
[0088] In addition, since the valve for realizing the capacity
variation of the scroll compressor is designed to be controlled by
fluid pressure that is not still compressed in the compressing part
and fluid pressure that is compressed in the compressing part
without adding additional components, the manufacturing cost of the
scroll compressor can be saved.
[0089] It will be apparent to those skilled in the art that various
modifications and variations can be made in the present invention.
Thus, it is intended that the present invention covers the
modifications and variations of this invention provided they come
within the scope of the appended claims and their equivalents.
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