U.S. patent application number 11/882475 was filed with the patent office on 2008-04-03 for rotary compressor and heat pump system.
This patent application is currently assigned to FUJITSU GENERAL LIMITED. Invention is credited to Taku Morishita, Naoya Morozumi, Kenshi Ueda.
Application Number | 20080078191 11/882475 |
Document ID | / |
Family ID | 38969900 |
Filed Date | 2008-04-03 |
United States Patent
Application |
20080078191 |
Kind Code |
A1 |
Morishita; Taku ; et
al. |
April 3, 2008 |
Rotary compressor and heat pump system
Abstract
A problem to be solved by the present invention is that the
temperature of a refrigerant discharged from a compression section
can be detected more exactly without being influenced by variable
factors existing around the compression section. In a rotary
compressor 1 having a motor 6 and a compression section 3 provided
in a closed container 2, and also having a discharge pipe 26
provided in an upper part of the closed container 2 to discharge a
refrigerant compressed by the compression section 3 to the outside
of the closed container 2, a refrigerant discharge part 462 for
discharging the refrigerant compressed by the compression section 3
toward the inner peripheral surface of the closed container 2 is
provided, and a discharge temperature sensor 20 for detecting the
discharge temperature of compressed refrigerant is arranged in a
portion opposed to the refrigerant discharge part 462 on the outer
peripheral surface side of the closed container 2.
Inventors: |
Morishita; Taku;
(Kawasaki-shi, JP) ; Morozumi; Naoya;
(Kawasaki-shi, JP) ; Ueda; Kenshi; (Kawasaki-shi,
JP) |
Correspondence
Address: |
KANESAKA BERNER AND PARTNERS LLP
1700 DIAGONAL RD, SUITE 310
ALEXANDRIA
VA
22314-2848
US
|
Assignee: |
FUJITSU GENERAL LIMITED
Kawasaki-shi
JP
|
Family ID: |
38969900 |
Appl. No.: |
11/882475 |
Filed: |
August 2, 2007 |
Current U.S.
Class: |
62/126 ; 62/160;
62/296 |
Current CPC
Class: |
F25B 2600/21 20130101;
F04C 18/3564 20130101; F25D 29/005 20130101; F25B 2600/2513
20130101; F25B 2600/0253 20130101; F04C 23/001 20130101; F04C
29/042 20130101; F25B 2600/2509 20130101; F04C 23/008 20130101;
F25B 2700/21152 20130101; F25B 49/02 20130101; F25B 1/04 20130101;
F04C 2270/19 20130101; Y02B 30/70 20130101; Y02B 30/741 20130101;
F25B 2400/23 20130101; F25B 2400/13 20130101 |
Class at
Publication: |
62/126 ; 62/160;
62/296 |
International
Class: |
F25B 49/02 20060101
F25B049/02; F25B 13/00 20060101 F25B013/00; F25D 19/00 20060101
F25D019/00 |
Foreign Application Data
Date |
Code |
Application Number |
Sep 29, 2006 |
JP |
2006-266429 |
May 11, 2007 |
JP |
2007-126573 |
Claims
1. A rotary compressor comprising: a cylindrical closed container
arranged vertically; a motor provided in an upper part of the
closed container; and a compression section which is provided in a
lower part of the closed container and is driven by a shaft fixed
to a rotor of the motor, the compression section having: a cylinder
provided with a compression chamber therein; an upper bearing and a
lower bearing each of which is fixed to the cylinder and has an end
plate part for closing the end surface of the compression chamber
and a bearing part for rotatably supporting the shaft; a
compression section discharge hole which is provided in the end
plate part of the upper bearing and is open to the compression
chamber; an upper muffler cover which is fixed on the upper side of
the end plate part of the upper bearing and forms an upper muffler
chamber by covering the compression section discharge hole; an
upper muffler discharge hole which is provided in the upper muffler
cover and is open to the closed container; and a discharge pipe
which is provided in an upper end part of the closed container to
discharge a refrigerant in the closed container to the outside of
the closed container, wherein a discharge temperature sensor for
detecting the temperature of compressed refrigerant is provided on
the outer peripheral surface of the closed container approximately
at the height at which the upper muffler discharge hole is
positioned.
2. The rotary compressor according to claim 1, wherein the upper
muffler cover has a horizontal end plate part, a vertical side
plate part, and an upper muffler discharge hole which is provided
in the side plate part and is open toward the inner peripheral
surface of the closed container; and a discharge temperature sensor
for detecting the temperature of compressed refrigerant is provided
on the outer peripheral surface of the closed container opposed to
the upper muffler discharge hole.
3. The rotary compressor according to claim 1, wherein the upper
muffler cover has a horizontal end plate part, a vertical side
plate part, and a cut and raised part which is provided in the end
plate part and is open toward the inner peripheral surface of the
closed container as an upper muffler discharge hole; and a
discharge temperature sensor for detecting the temperature of
compressed refrigerant is provided on the outer peripheral surface
of the closed container opposed to the upper muffler discharge
hole.
4. The rotary compressor according to claim 1, wherein the upper
muffler cover has an upper muffler pipe which is fixed to the upper
muffler cover and one end of which is open to the upper muffler
chamber and the other end of which is open toward the inner
peripheral surface of the closed container as an upper muffler
discharge hole; and a discharge temperature sensor for detecting
the temperature of compressed refrigerant is provided on the outer
peripheral surface of the closed container opposed to the upper
muffler discharge hole.
5. The rotary compressor according to claim 1, wherein the upper
muffler cover has a horizontal end plate part, a vertical side
plate part, a projecting part provided in the side plate part so as
to be close to the inner peripheral surface of the closed
container, and an upper muffler discharge hole which is provided in
the projecting part and is open toward the inner peripheral surface
of the closed container; and a discharge temperature sensor for
detecting the temperature of compressed refrigerant is provided on
the outer peripheral surface of the closed container opposed to the
upper muffler discharge hole.
6. The rotary compressor according to claim 1, wherein the end
plate part of the upper bearing has a bearing end plate discharge
passage one end of which is open to the upper muffler chamber and
the other end of which is open toward the inner peripheral surface
of the closed container as an upper muffler discharge hole; and a
discharge temperature sensor for detecting the temperature of
compressed refrigerant is provided on the outer peripheral surface
of the closed container opposed to the upper muffler discharge
hole.
7. The rotary compressor according to claim 1, wherein the number
of revolutions of the rotary compressor is variable.
8. The rotary compressor according to claim 1, wherein the
compression section has a low stage side compression section
arranged on the lower side, a high stage side compression section
arranged on the upper side, an intermediate interconnection passage
which connects the discharge side of the low stage side compression
section to the suction side of the high stage side compression
section, a low-pressure suction pipe connected to the suction side
of the low stage side compression section, and an
intermediate-pressure suction pipe connected to the intermediate
interconnection passage.
9. A heat pump system comprising a refrigeration cycle in which a
compressor, a condenser, an expansion mechanism, and an evaporator
are connected in succession by a line; and a control unit which
detects the temperatures of a plurality of locations of the
refrigeration cycle and controls the number of revolutions of the
compressor and the throttle amount of the expansion mechanism,
wherein the rotary compressor described in claim 1 is used as the
compressor; and based on the temperature detected by a discharge
temperature sensor provided on the outer peripheral surface of a
closed container of the compressor, the throttle amount of the
expansion mechanism and the number of revolutions of the compressor
are controlled, and the degree of superheat of a refrigerant sucked
into the compressor is kept proper.
10. A heat pump system provided with a gas injection cycle, which
comprises a basic refrigeration cycle in which a compressor, a
condenser, a basic cycle expansion mechanism, and an evaporator are
connected in succession by a line; a branch pipe which branches
some of a high-pressure refrigerant behind the outlet of the
condenser from the basic refrigeration cycle as an injection
refrigerant; an injection expansion mechanism which decompresses
the injection refrigerant to an intermediate pressure between the
pressure of the condenser and the pressure of the evaporator; an
internal heat exchanger which heat-exchanges the decompressed
injection refrigerant with the branched high-pressure refrigerant
of basic refrigeration cycle; an injection line which sucks the
injection refrigerant, having been subjected to the heat exchange,
during the compression process of the compressor; and a control
unit which detects the temperatures of a plurality of locations of
the refrigeration cycle and controls the number of revolutions of
the compressor, the throttle amount of the basic cycle expansion
mechanism, and the throttle amount of the injection expansion
mechanism, wherein the rotary compressor described in claim 8 is
used as the compressor, the discharge pipe of the compressor is
connected to the condenser, the low-pressure suction pipe of the
compressor is connected to the evaporator, and the
intermediate-pressure suction pipe of the compressor is connected
to the injection line; and based on the temperature detected by a
discharge temperature sensor provided on the outer peripheral
surface of a closed container of the compressor, the throttle
amount of the injection expansion mechanism and the number of
revolutions of the compressor are controlled, and the degree of
superheat or the dryness of a refrigerant sucked into the
intermediate-pressure suction pipe of the compressor is kept
proper.
11. A heat pump system provided with a gas injection cycle, which
comprises a basic refrigeration cycle configured by connecting a
compressor, a condenser, a first expansion mechanism, an
intermediate-pressure gas-liquid separator, a second expansion
mechanism, and an evaporator in succession by a line; an injection
pipe which branches a gas refrigerant separated by the
intermediate-pressure gas-liquid separator from the basic
refrigeration cycle as an injection refrigerant and sucks the
injection refrigerant during the compression process of the
compressor; and a control unit which detects the temperatures of a
plurality of locations of the refrigeration cycle and controls the
number of revolutions of the compressor, the throttle amount of the
first expansion mechanism, and the throttle amount of the second
expansion mechanism, wherein the rotary compressor described in
claim 8 is used as the compressor, the discharge pipe of the
compressor is connected to the condenser, the low-pressure suction
pipe of the compressor is connected to the evaporator, and the
intermediate-pressure suction pipe of the compressor is connected
to the injection line; and based on the temperature detected by a
discharge temperature sensor provided on the outer peripheral
surface of a closed container of the compressor, the throttle
amount of the first expansion mechanism, the throttle amount of the
second expansion mechanism, and the number of revolutions of the
compressor are controlled, and the degree of superheat or the
dryness of a refrigerant sucked into the intermediate-pressure
suction pipe of the compressor is kept proper.
Description
TECHNICAL FIELD
[0001] The present invention relates to a rotary compressor used
for air conditioners and water heaters. More particularly, it
relates to a technique used to control the capacity of a heat pump
system and to ensure the reliability of a compressor by exactly
detecting the discharge temperature of a refrigerant compressed by
a compression section.
BACKGROUND ART
[0002] The compressor used for the refrigeration cycle of a heat
pump system has a problem in that if the degree of superheat of the
intake refrigerant thereof is too high, the density of intake
refrigerant decreases, so that the capacity and efficiency of
compressor decreases, and a problem in that the temperature of the
whole of the compressor rises, so that the reliability of
compressor, especially the durability of motor winding and
insulating paper, decreases.
[0003] On the other hand, if the intake refrigerant is not in a
superheated state but in a wet state, that is, in a state in which
the ratio of liquid is high, the lubricating oil in the compression
section is diluted by a liquid refrigerant, resulting in poor
lubrication. If the ratio of liquid increases further, the intake
refrigerator becomes in a liquid compression state, which presents
a problem in that an abnormal rise in pressure leads to damage of
compression section.
[0004] Therefore, in order to properly control the capacity of heat
pump system and to ensure the reliability of compressor, it is
necessary to properly keep the state of refrigerant in the
refrigeration system in the heat pump system, especially the degree
of superheat of the intake refrigerant of compressor.
[0005] If the intake refrigerant in the compressor is in a wet
state, that is, in a two-phase state, the temperature of intake
refrigerant in the compressor does not change regardless of the
ratio of liquid. Generally, therefore, the temperature of discharge
refrigerant after being compressed is detected, by which the intake
state is estimated from the fact that the compression is
substantially in an adiabatic process.
[0006] Thereupon, for example, in Patent Document 1 (Japanese
Patent Application Publication No. 2005-147437), a discharge
temperature sensor is provided in the discharge pipe of compressor.
Also, in Patent Document 2 (Japanese Patent Application Publication
No. H07-174417), a discharge temperature sensor is provided within
the compressor, the degree of superheat of intake refrigerant in
the compressor is estimated by using the detected discharge
refrigerant temperature of compressor as one piece of information,
and to make the degree of superheat in a proper state, the throttle
amount of an expansion valve, the number of revolutions of the
compressor, and the number of revolutions of a fan of a condenser
or an evaporator are controlled.
[0007] However, the mode in which the discharge temperature sensor
is provided in the discharge pipe above the compressor as in Patent
Document 1 has problems described below.
[0008] The compression section of a general hermetic rotary
compressor is arranged in a lower part of a closed container, and
therefore the refrigerant discharged from the compression section
passes through the surroundings of the motor arranged in an upper
part of the closed container and is discharged to the outside of
the closed container through the discharge pipe in an upper
part.
[0009] Therefore, the compressor of this type has both of a cause
for the rise in temperature due to absorption of loss heat of motor
during the time from when the refrigerant is discharged from the
compression section to when it reaches the discharge pipe and a
cause for the fall in temperature due to heat release from the
compressor to the surroundings thereof, so that the temperature
detected in the discharge pipe in the upper part of the compressor
differs from the temperature immediately after the discharge from
the compression section.
[0010] In addition, in a transient state such as the start time,
depending on the heat capacity of motor, the temperature detected
in the discharge pipe in the upper part of the compressor differs
greatly from the temperature immediately after the discharge from
the compression section. Therefore, this method is insufficient for
detecting exact temperature immediately after the discharge from
the compression section, which is necessary for estimating the
degree of superheat of intake refrigerant, so that this method must
be improved.
[0011] Also, in the mode in which the discharge temperature sensor
is provided within the compressor as in Patent Document 2, since
the signal of the discharge temperature sensor is taken out to the
outside, a pressure-tight junction terminal must be provided in the
closed container of compressor, which leads to an increase in cost,
so that this method must be improved.
[0012] Further, in the gas injection cycle in the refrigeration
cycle, for the injection refrigerant sucked into the compressor as
well, it is necessary to properly keep the degree of superheat or
the dryness in the compressor intake state.
[0013] The injection refrigerant is generally sucked into the
compressor without passing through an accumulator. Therefore, to
properly keep the degree of superheat or the dryness in the
compressor intake state of the injection refrigerant, it is
necessary to more exactly detect the discharge temperature of
compressor.
[0014] Therefore, a problem to be solved by the present invention
is that in a rotary compressor in which a motor and a compression
section are contained in a closed container, the temperature of a
refrigerant discharged from the compression section can be detected
more exactly without being influenced by variable factors existing
around the compression section, by which the capacity of a heat
pump system is controlled properly, and the reliability of
compressor is ensured.
SUMMARY OF THE INVENTION
[0015] To solve the above problem, the present invention provides a
closed rotary compressor of what is called an interior high
pressure type, that is, a type in which the compressor has a motor
provided in an upper part of a cylindrical closed container and a
compression section provided in a lower part thereof, and a
refrigerant compressed by the compression section is discharged to
the outside through a discharge pipe provided in an upper end part
of the closed container after passing through the interior of the
closed container, wherein a muffler chamber is provided on the
upper side of the compression section to reduce pressure pulsation
of refrigerant discharged from the compression section, and to
detect the temperature of compressed refrigerant near an upper
muffler discharge hole for discharging the refrigerant from the
muffler chamber into the closed container, a discharge temperature
sensor for detecting the temperature of compressed refrigerant is
provided on the outer peripheral surface of the closed container
approximately at the height at which the upper muffler discharge
hole is positioned.
[0016] As a preferable mode of the present invention, an upper
muffler cover has a horizontal end plate part, a vertical side
plate part, and the upper muffler discharge hole which is provided
in the side plate part and is open toward the inner peripheral
surface of the closed container; and a discharge temperature sensor
for detecting the temperature of compressed refrigerant is provided
on the outer peripheral surface of the closed container opposed to
the upper muffler discharge hole.
[0017] The upper muffler cover has a horizontal end plate part, a
vertical side plate part, and a cut and raised part which is
provided in the end plate part and is open toward the inner
peripheral surface of the closed container as an upper muffler
discharge hole; and a discharge temperature sensor for detecting
the temperature of compressed refrigerant is provided on the outer
peripheral surface of the closed container opposed to the upper
muffler discharge hole.
[0018] The upper muffler cover has an upper muffler pipe which is
fixed to the upper muffler cover and one end of which is open to an
upper muffler chamber and the other end of which is open toward the
inner peripheral surface of the closed container as an upper
muffler discharge hole; and a discharge temperature sensor for
detecting the temperature of compressed refrigerant is provided on
the outer peripheral surface of the closed container opposed to the
upper muffler discharge hole.
[0019] The upper muffler cover has a horizontal end plate part, a
vertical side plate part, a projecting part provided in the side
plate part so as to be close to the inner peripheral surface of the
closed container, and an upper muffler discharge hole which is
provided in the projecting part and is open toward the inner
peripheral surface of the closed container; and a discharge
temperature sensor for detecting the temperature of compressed
refrigerant is provided on the outer peripheral surface of the
closed container opposed to the upper muffler discharge hole.
[0020] The end plate part of the upper bearing has a bearing end
plate discharge passage one end of which is open to the upper
muffler chamber and the other end of which is open toward the inner
peripheral surface of the closed container as an upper muffler
discharge hole; and a discharge temperature sensor for detecting
the temperature of compressed refrigerant is provided on the outer
peripheral surface of the closed container opposed to the upper
muffler discharge hole.
[0021] On the other hand, the present invention is preferably
applied to a rotary compressor in which the number of revolutions
is variable.
[0022] Also, the present invention is preferably applied to a
two-stage compression rotary compressor in which the compression
section has a low stage side compression section arranged on the
lower side, a high stage side compression section arranged on the
upper side, a two-stage compression section being formed by
connecting the discharge side of the low stage side compression
section to the suction side of the high stage side compression
section by an intermediate interconnection passage; and the
compression section also has a low-pressure suction pipe connected
to the suction side of the low stage side compression section, and
an intermediate-pressure suction pipe connected to the suction side
of the high stage side compression section via the intermediate
interconnection passage.
[0023] Further, the present invention embraces any mode described
below as a heat pump system using the rotary compressor in
accordance with the present invention.
[0024] A heat pump system including a refrigeration cycle in which
a compressor, a condenser, an expansion mechanism, and an
evaporator are connected in succession by a line; and a control
unit which detects the temperatures of a plurality of locations of
the refrigeration cycle and controls the number of revolutions of
the compressor and the throttle amount of the expansion mechanism,
wherein the rotary compressor described in any one of claims 1 to 7
is used as the compressor; and based on the temperature detected by
a discharge temperature sensor provided on the outer peripheral
surface of a closed container of the compressor, the throttle
amount of the expansion mechanism and the number of revolutions of
the compressor are controlled, and the degree of superheat of a
refrigerant sucked into the compressor is kept proper.
[0025] A heat pump system provided with a gas injection cycle,
which includes a basic refrigeration cycle in which a compressor, a
condenser, a basic cycle expansion mechanism, and an evaporator are
connected in succession by a line; a branch pipe which branches
some of a high-pressure refrigerant behind the outlet of the
condenser from the basic refrigeration cycle as an injection
refrigerant; an injection expansion mechanism which decompresses
the injection refrigerant to an intermediate pressure between the
pressure of the condenser and the pressure of the evaporator; an
internal heat exchanger which heat-exchanges the decompressed
injection refrigerant with the branched high-pressure refrigerant
of basic refrigeration cycle; an injection line which sucks the
injection refrigerant, having been subjected to the heat exchange,
during the compression process of the compressor; and a control
unit which detects the temperatures of a plurality of locations of
the refrigeration cycle and controls the number of revolutions of
the compressor, the throttle amount of the basic cycle expansion
mechanism, and the throttle amount of the injection expansion
mechanism, wherein the rotary compressor described in claim 8 is
used as the compressor, the discharge pipe of the compressor is
connected to the condenser, the low-pressure suction pipe of the
compressor is connected to the evaporator, and the
intermediate-pressure suction pipe of the compressor is connected
to the injection line; and based on the temperature detected by a
discharge temperature sensor provided on the outer peripheral
surface of a closed container of the compressor, the throttle
amount of the injection expansion mechanism and the number of
revolutions of the compressor are controlled, and the degree of
superheat or the dryness of a refrigerant sucked into the
intermediate-pressure suction pipe of the compressor is kept
proper.
[0026] A heat pump system provided with a gas injection cycle,
which includes a basic refrigeration cycle configured by connecting
a compressor, a condenser, a first expansion mechanism, an
intermediate-pressure gas-liquid separator, a second expansion
mechanism, and an evaporator in succession by a line; an injection
pipe which branches a gas refrigerant separated by the
intermediate-pressure gas-liquid separator from the basic
refrigeration cycle as an injection refrigerant and sucks the
injection refrigerant during the compression process of the
compressor; and a control unit which detects the temperatures of a
plurality of locations of the refrigeration cycle and controls the
number of revolutions of the compressor, the throttle amount of the
first expansion mechanism, and the throttle amount of the second
expansion mechanism, wherein the rotary compressor described in
claim 8 is used as the compressor, the discharge pipe of the
compressor is connected to the condenser, the low-pressure suction
pipe of the compressor is connected to the evaporator, and the
intermediate-pressure suction pipe of the compressor is connected
to the injection line; and based on the temperature detected by a
discharge temperature sensor provided on the outer peripheral
surface of a closed container of the compressor, the throttle
amount of the first expansion mechanism, the throttle amount of the
second expansion mechanism, and the number of revolutions of the
compressor are controlled, and the degree of superheat or the
dryness of a refrigerant sucked into the intermediate-pressure
suction pipe of the compressor is kept proper.
[0027] According to the present invention, in the rotary compressor
in which the motor and the compression section are contained in the
closed container, the temperature of refrigerant discharged from
the compression section can be detected more exactly without being
influenced by variable factors, such as the motor, existing around
the compression section.
[0028] Thereby, the state of refrigerant sucked into the
compressor, that is, the degree of superheat or the dryness thereof
can be estimated more exactly, and therefore the capacity of heat
pump system can be controlled and the reliability of compressor can
be ensured at a low cost.
[0029] Also, in a speed variable compressor, in the case where the
required capacity as a heat pump system is low and the number of
revolutions is small, that is, in the case where the refrigerant
circulating amount is small, the change in temperature caused by an
influence of the surroundings from immediately after the discharge
from the compression section to the discharge pipe in the upper
part of the compressor is large, so that the effect of the present
invention increases.
[0030] Further, according to the present invention, in the gas
injection cycle, the degree of superheat or the dryness of
injection refrigerant sucked into the compressor can be kept
proper.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1A is a general sectional view of a rotary compressor
in accordance with a first embodiment of the present invention;
[0032] FIG. 1B is a transverse sectional view of a compression
section of a rotary compressor in accordance with a first
embodiment of the present invention;
[0033] FIG. 1C is a configuration diagram of a refrigeration cycle
in accordance with a first embodiment of the present invention;
[0034] FIG. 2 is a partial sectional view of a lower part of a
rotary compressor in accordance with a second embodiment of the
present invention;
[0035] FIG. 3A is a perspective view of an upper muffler cover of a
rotary compressor in accordance with a third embodiment of the
present invention;
[0036] FIG. 3B is a partial sectional view of a lower part of a
rotary compressor in accordance with a third embodiment of the
present invention;
[0037] FIG. 4 is a partial sectional view of a lower part of a
rotary compressor in accordance with a fourth embodiment of the
present invention;
[0038] FIG. 5A is a perspective view of an upper muffler cover of a
rotary compressor in accordance with a fifth embodiment of the
present invention;
[0039] FIG. 5B is a partial sectional view of a lower part of a
rotary compressor in accordance with a fifth embodiment of the
present invention;
[0040] FIG. 6 is a partial sectional view of a lower part of a
rotary compressor in accordance with a sixth embodiment of the
present invention;
[0041] FIG. 7A is a general sectional view of a rotary compressor
in accordance with a seventh embodiment of the present
invention;
[0042] FIG. 7B is a configuration diagram of a refrigeration cycle
in accordance with a seventh embodiment of the present invention;
and
[0043] FIG. 8 is a configuration diagram of a refrigeration cycle
in accordance with an eighth embodiment of the present
invention.
DETAILED DESCRIPTION
[0044] First, a first embodiment of the present invention will be
described with reference to FIGS. 1A to 1C. FIG. 1A is a general
sectional view of a rotary compressor in accordance with the first
embodiment of the present invention, FIG. 1B is a transverse
sectional view of the compression section of the rotary compressor
in accordance with the first embodiment of the present invention,
and FIG. 1C is a configuration diagram of a refrigeration cycle in
accordance with the first embodiment of the present invention.
[0045] As shown in FIG. 1A, a rotary compressor 1 is configured so
that a cylindrical closed container 2 is arranged in the vertical
direction, and a motor 6 and a compression section 3 are provided
in an upper part and a lower part of the closed container,
respectively. In this embodiment, the compression section 3 is a
two-cylinder type rotary compressor having a first compression
section 3A and a second compression section 3B.
[0046] In an upper end part of the closed container 2, there is
provided a discharge pipe 26 for discharging a refrigerant
discharged from the compression section 3 into the closed container
to the outside of the closed container. A stator 61 of the motor 6
is shrinkage fitted in the closed container 2, and a rotor 62 of
the motor 6 is shrinkage fitted on a shaft 31 that mechanically
connects the motor 6 to the compression section 3.
[0047] As shown in FIG. 1B, the compression section 3 has a
cylinder 32 and a cylindrical piston 33 housed in a cylindrical
cylinder bore 321 formed on the inside of the cylinder 32, and a
working chamber 11 for the refrigerant is formed between the inner
peripheral surface of the cylinder bore 321 and the outer
peripheral surface of the piston 33. The cylinder 32 is provided
with a vane groove 322 extending from the cylinder bore 321 toward
the outer periphery of the cylinder 32, and a flat plate-shaped
vane 34 is provided in the vane groove 322.
[0048] Between the vane 34 and the inner peripheral surface of the
closed container 2, a spring 38 is provided so that the tip end of
the vane 34 is brought into sliding contact with the outer
peripheral surface of the piston 33 by an urging force of the
spring 38, and thereby the working chamber 11 is partitioned into a
suction chamber 111 and a compression chamber 112.
[0049] The upper first compression section 3A and the lower
compression section 3B of the compression section 3 have the same
basic configuration except that the pistons 33 are out of phase by
180.degree.. Next, referring again to FIG. 1A, the whole of the
compressor 1 is explained.
[0050] The compression section 3 has a first cylinder 32A
corresponding to the first compression section 3A, a second
cylinder 32B corresponding to the second compression section 3B, an
upper bearing 36 provided on the upper side of the first cylinder
32A, a lower bearing 37 provided on the lower side of the second
cylinder 32B, and an intermediate partitioning plate 35 provided
between the first cylinder 32A and the second cylinder 32B, so that
the upper and lower sides of the working chambers 11 of the two
compression sections 3A and 3B are closed by an end plate part 361
of the upper bearing 36, the intermediate partitioning plate 35,
and an end plate part 371 of the lower bearing.
[0051] On the upper side of the upper bearing 36 and on the lower
side of the lower bearing, an upper muffler cover 46 and a lower
muffler cover 47 are provided, respectively, and an upper muffler
chamber 56 and a lower muffler chamber 57 are formed to reduce
pressure pulsation of the discharged refrigerant.
[0052] The upper muffler cover 46, the upper bearing 36, the first
cylinder 32A, the intermediate partitioning plate 35, the second
cylinder 32B, the lower bearing 37, and the lower muffler cover 47
are fixed integrally with bolts (not shown), and further the outer
peripheral part of the upper bearing end plate part 361 is fixed to
the closed container 2 by spot welding.
[0053] The upper bearing 36 and the lower bearing 37 have bearing
parts 362 and 372, respectively. By fitting the shaft 31 in the
bearing parts 362 and 372, the shaft 31 is rotatably supported.
[0054] The shaft 31 has two crank parts 311a and 311b that are
off-center in the 180.degree. different direction, and the two
crank parts 311a and 311b fit in the pistons 33 in the first
compression section 3A and the second compression section 3B,
respectively.
[0055] As the shaft 31 rotates, the piston 33 revolves while making
sliding contact with the inner wall of the cylinder bore 321.
Accordingly, the vane 34 reciprocates following the revolution of
the piston 33, by which the volumes of the suction chamber 111 and
the compression chamber 112 are changed continuously.
[0056] The suction chamber 111 of the first compression section 3A
is connected to a low-pressure suction pipe 71 via a suction hole
323A provided in the first cylinder 32A, and the compression
chamber 112 of the first compression section 3A communicates with
the upper muffler chamber 56 via a compression section discharge
hole 363 provided in the upper bearing end plate part 361.
[0057] More specifically, the low-pressure suction pipe 71 is
connected to the suction hole 323A via a suction connection pipe
27, and a check valve 364 is provided in the compression section
discharge hole 363.
[0058] The suction chamber 111 on the suction side of the second
compression section 3B is connected to a low-pressure suction pipe
71 via a suction hole 323B provided in the second cylinder 32B, and
the compression chamber 112 of the second compression section 3B
communicates with the lower muffler chamber 57 via a compression
section discharge hole 373 provided in the lower bearing end plate
part 371.
[0059] More specifically, the low-pressure suction pipe 71 is
connected to the suction hole 323B via a suction connection pipe
27, and a check valve 374 is provided in the compression section
discharge hole 373.
[0060] The check valves 364 and 374 are additionally provided with
valve guards 364a and 374a, respectively. FIG. 1A shows a state in
which the check valves 364 and 374 are opened and are in contact
with the valve guards 364a and 374a, respectively.
[0061] In the upper bearing end plate part 361, the first cylinder
32A, the intermediate partitioning plate 35, the second cylinder
32B, and the lower bearing end plate part 371, a muffler chamber
communication hole (not shown) that passes through these elements
continuously to cause the upper muffler chamber 56 and the lower
muffler chamber 57 to communicate with each other is provided.
[0062] In the upper muffler cover 46, an upper muffler discharge
hole 462 that opens to the interior of the closed container 2 is
provided, and a discharge temperature sensor 20 is mounted on the
outer peripheral surface of the closed container 2 approximately at
the height of the upper muffler discharge hole 462.
[0063] At the side of the compressor 1, an accumulator 7 consisting
of an independent closed vessel is provided. At an upper part of
the accumulator 7, an accumulator inlet pipe 72 connecting with the
low-pressure side of a refrigeration cycle is provided, and at
lower parts of the accumulator 7, the two low-pressure suction
pipes 71 that connect the interior of the accumulator 7 to the
suction chambers 111 of the first compression section 3A and the
second compression section 3B are provided.
[0064] The accumulator 7 is used to prevent a liquid refrigerant
from being sucked into the compressor in the case where the liquid
refrigerant is mixed in an intake refrigerant in a transient state
such as the start time of compressor. The explanation of the
internal construction of the accumulator 7 is omitted because the
internal construction thereof does not relate directly to the
present invention.
[0065] Next, the flow of refrigerant in the compressor configured
as described above is explained. A refrigerant flowing from the
low-pressure side (evaporator side) of the refrigeration cycle into
the accumulator 7 through the accumulator inlet pipe 72 is sucked
into the suction chambers 111 of the first compression section 3A
and the second compression section 3B of the compressor 1 through
the low-pressure suction pipes 71, since the piston 33 revolves and
thus the volume of the suction chamber 111 increases.
[0066] After one turn, the suction chamber 111 is located at a
position at which it is isolated from the suction hole 323, and is
changed over to the compression chamber 112 as it is, by which the
refrigerant is compressed.
[0067] When the pressure of the compressed refrigerant reaches the
pressure in the closed container 2 on the outside of the check
valves 364 and 374 provided in the compression section discharge
holes 363 and 373, respectively, as shown in FIG. 1A, the check
valves 364 and 374 are opened, and the refrigerant is discharged
into the upper muffler chamber 56 and the lower muffler chamber
57.
[0068] The refrigerant discharged into the lower muffler chamber 57
reduces the pressure pulsation, which may cause noise, in the lower
muffler chamber 57, and then flows into the upper muffler chamber
56 through the muffler chamber communication hole (not shown),
joining to the refrigerant discharged from the first compression
section 3A.
[0069] The joined refrigerant reduces the pressure pulsation, which
may cause noise, in the upper muffler chamber 56, and then is
discharged into the closed container 2 through the upper muffler
discharge hole 462.
[0070] Further, the refrigerant is introduced into a space above
the motor 6 after passing through a notch portion (not shown) of a
stator core 612 of the motor 6, a gap between the stator core 612
and a winding 611, and a gap between the stator 61 and the rotor
62, and is discharged to a high-pressure side (condenser side) of
the refrigeration cycle through the discharge pipe 26.
[0071] As described above, the refrigerant compressed in the first
compression section 3A and the second compression section 3B is
discharged into the closed container 2 after passing through the
upper muffler chamber 56, and is discharged to the outside of the
closed container 2 through the discharge pipe 26 after passing
through the surroundings of the motor 6.
[0072] As shown in FIG. 1C, the refrigeration cycle is formed by
connecting the compressor 1, a condenser 91, a basic cycle
expansion mechanism 93, and an evaporator 92 in succession by using
a line 99. In FIG. 1C, reference symbol Ta denotes a temperature
sensor for detecting the refrigerant temperature on the outlet side
of the condenser 91, Tb denotes a temperature sensor for detecting
the refrigerant temperature at an intermediate position in the
condenser 91, Tc denotes a temperature sensor for detecting the
refrigerant temperature at an intermediate position in the
evaporator 92, and Td denotes a sensor for detecting the
temperature of intake refrigerant.
[0073] The high temperature and pressure gas refrigerant discharged
from the compressor 1 is heat-exchanged with air in the condenser
91 to release heat, and becomes in a supercooled state. The
refrigerant in the supercooled state is decompressed in the basic
cycle expansion mechanism 93 and becomes in a low temperature and
pressure two-phase state. The refrigerant in the low temperature
and pressure two-phase state is heat-exchanged with air in the
evaporator 92 to absorb heat and to be gasified, that is, becomes
in a state having a degree of superheat, and is sucked into the
compressor 1.
[0074] In the case where the evaporator 92 is arranged in an indoor
unit, the indoor air is cooled, so that the heat pump system serves
as a cooler, and in the case where the condenser 91 is arranged in
an indoor unit, the indoor air is heated, so that the heat pump
system serves as a heater. Though not shown in FIG. 1C, if a line
and a selector valve for exchanging the evaporator and the
condenser for each other are added, the heat pump system can be
used as a cooling and heating machine. Also, if the condenser 91 is
heat-exchanged with water for hot-water supply, the heat pump
system serves as a water heater.
[0075] Also, the heat pump system of this embodiment is provided
with a control unit 97 for keeping the refrigerant in the
refrigeration cycle in a proper state.
[0076] The control unit 97 sends a signal for detecting at least
condenser refrigerant temperature, evaporator refrigerant
temperature, and compressor discharge temperature and controlling
the throttle amount of the basic cycle expansion mechanism 93 and
the number of revolutions of the compressor 1 to keep the
refrigerant circulating amount of refrigeration cycle proper with
respect to the capacity required in the heat pump system, and
further to keep the state of refrigerant in the refrigeration
cycle, that is, the degree of supercooling of refrigerant at the
outlet of the condenser 91 in the refrigeration cycle and the
degree of superheat of refrigerant in the low-pressure suction pipe
71 of the compressor 1 proper.
[0077] In the present invention, the discharge temperature sensor
20 is mounted on the outer peripheral surface of closed container
opposed to a portion in which the refrigerant compressed in the
closed container 2 of the compressor 1 comes into contact with the
closed container 2 before passing through the surroundings of the
motor 6, by which the refrigerant temperature before heat exchange
with the motor 6, that is, immediately after the discharge from the
compression section can be detected almost directly. Therefore, the
throttle amount of the basic cycle expansion mechanism 93 and the
number of revolutions of the compressor 1 can be controlled based
on the detected temperature, and the degree of superheat of
refrigerant in the low-pressure suction pipe 71 of the compressor 1
can be kept more proper.
[0078] Also, in a speed variable compressor, in the case where the
required capacity as a heat pump system is low and the number of
revolutions is small, that is, in the case where the refrigerant
circulating amount is small, the change in temperature caused by an
influence of the surroundings from immediately after the discharge
from the compression section to the discharge pipe 26 in the upper
part of the closed container 2 is large, so that the effect of the
present invention increases.
[0079] Next, a second embodiment of the present invention is
explained with reference to FIG. 2. FIG. 2 is a partial sectional
view of the lower part of a rotary compressor in accordance with
the second embodiment of the present invention. In FIG. 2, the same
reference symbols are applied to elements that are the same as
those in FIG. 1A showing the first embodiment, and the detailed
explanation thereof is omitted. The refrigeration cycle is the same
as that in the first embodiment shown in FIG. 1C.
[0080] As shown in FIG. 2, the upper muffler cover 46 has an end
plate part 463 and a side plate part 464, and an upper muffler
discharge hole 462 is provided in the side plate part 464 so that
the refrigerant discharged from the upper muffler chamber 56 is
directly sprayed onto the inner peripheral surface of the closed
container 2. Further, the discharge temperature sensor 20 is
mounted on the outer peripheral surface of the closed container 2
opposed to the sprayed portion.
[0081] Thereby, the difference between the closed container
temperature in the portion in which the discharge temperature
sensor 20 is mounted and the refrigerant temperature immediately
after the discharge from the compression section can be made small
as compared with the first embodiment, so that the degree of
superheat of intake refrigerant can be kept proper with higher
accuracy.
[0082] Next, a third embodiment of the present invention is
explained with reference to FIGS. 3A and 3B. FIG. 3A is a
perspective view of the upper muffler cover of a rotary compressor
in accordance with the third embodiment of the present invention,
and FIG. 3B is a partial sectional view of a lower part of the
rotary compressor in accordance with the third embodiment of the
present invention. In FIGS. 3A and 3B, the same reference symbols
are applied to elements that are the same as those in FIG. 1A
showing the first embodiment, and the detailed explanation thereof
is omitted. The refrigeration cycle is the same as that in the
first embodiment shown in FIG. 1C.
[0083] As shown in FIG. 3A, in the third embodiment, a cut and
raised part 465 capable of being pressed simultaneously with the
pressing of the whole of the upper muffler cover is provided in the
end plate part 463 of the upper muffler cover 46.
[0084] As shown in FIG. 3B, the cut and raised part 465 is open
toward the inner peripheral surface of the closed container 2 as
the upper muffler discharge hole 462 so that the refrigerant
discharged from the upper muffler chamber 56 is sprayed directly
onto the inner peripheral surface of the closed container 2.
Further, the discharge temperature sensor 20 is mounted on the
outer peripheral surface of the closed container 2 opposed to the
sprayed portion.
[0085] Thereby, the upper muffler discharge hole 462 that is open
toward the inner surface of the closed container can be formed
without separately fabricating the side plate part 464 of the upper
muffler cover 46 as compared with the second embodiment, so that
the degree of superheat of intake refrigerant can be kept proper
with high accuracy at a lower cost.
[0086] Next, a fourth embodiment of the present invention is
explained with reference to FIG. 4. FIG. 4 is a partial sectional
view of the lower part of a rotary compressor in accordance with
the fourth embodiment of the present invention. In FIG. 4, the same
reference symbols are applied to elements that are the same as
those in FIG. 1A showing the first embodiment, and the detailed
explanation thereof is omitted. The refrigeration cycle is the same
as that in the first embodiment shown in FIG. 1C.
[0087] As shown in FIG. 4, in the fourth embodiment, an L-shaped
upper muffler pipe 466 one end of which is open to the upper
muffler chamber 56 and the other end of which is open toward the
inner peripheral surface of the closed container 2 as the upper
muffler discharge hole 462 is fixed to the end plate part 463 of
the upper muffler cover 46 so that the refrigerant discharged from
the upper muffler chamber 56 is sprayed directly onto the inner
peripheral surface of the closed container 2. Further, the
discharge temperature sensor 20 is mounted on the outer peripheral
surface of the closed container 2 opposed to the sprayed
portion.
[0088] Thereby, the upper muffler discharge hole 462 can be opened
close to the inner peripheral surface of the closed container 2 as
compared with the second and third embodiments, so that the degree
of superheat of intake refrigerant can be kept proper with still
higher accuracy.
[0089] Next, a fifth embodiment of the present invention is
explained with reference to FIGS. 5A and 5B. FIG. 5A is a
perspective view of the upper muffler cover of a rotary compressor
in accordance with the fifth embodiment of the present invention,
and FIG. 5B is a partial sectional view of the lower part of the
rotary compressor in accordance with the fifth embodiment of the
present invention. In FIGS. 5A and 5B, the same reference symbols
are applied to elements that are the same as those in FIG. 1A
showing the first embodiment, and the detailed explanation thereof
is omitted. The refrigeration cycle is the same as that in the
first embodiment shown in FIG. 1C.
[0090] As shown in FIG. 5A, in the fifth embodiment, a projecting
part 467 that is formed by bringing a part of the side plate part
464 of the upper muffler cover 46 close to the inner peripheral
surface of the closed container 2 is provided, and further an
opening 468 is provided in this projecting part 467.
[0091] As shown in FIG. 5B, the opening 468 in the projecting part
is used as the upper muffler discharge hole 462 that is open toward
the inner peripheral surface of the closed container 2 so that the
refrigerant discharged from the upper muffler chamber 56 is sprayed
directly onto the inner peripheral surface of the closed container
2. Further, the discharge temperature sensor 20 is mounted on the
outer peripheral surface of the closed container 2 opposed to the
sprayed portion.
[0092] Thereby, the upper muffler discharge hole 462 that is open
close to the inner peripheral surface of the closed container 2 can
be formed without attaching a separate pipe to the upper muffler
cover 46 as compared with the fourth embodiment, so that the degree
of superheat of intake refrigerant can be kept proper with far
higher accuracy at a lower cost.
[0093] Next, a sixth embodiment of the present invention is
explained with reference to FIG. 6. FIG. 6 is a partial sectional
view of the lower part of a rotary compressor in accordance with
the sixth embodiment of the present invention. In FIG. 6, the same
reference symbols are applied to elements that are the same as
those in FIG. 1A showing the first embodiment, and the detailed
explanation thereof is omitted. The refrigeration cycle is the same
as that in the first embodiment shown in FIG. 1C.
[0094] As shown in FIG. 6, in the sixth embodiment, a bearing end
plate discharge passage 365 one end of which is open to the upper
muffler chamber 56 and the other end of which is open toward the
inner peripheral surface of the closed container 2 as the upper
muffler discharge hole 462 is provided in the end plate part 361 of
the upper bearing so that the refrigerant discharged from the upper
muffler chamber 56 is sprayed directly onto the inner peripheral
surface of the closed container 2. Further, the discharge
temperature sensor 20 is mounted on the outer peripheral surface of
the closed container 2 opposed to the sprayed portion.
[0095] Thereby, an opening can be provided close to the inner
peripheral surface of the closed container 2 without providing the
upper muffler discharge hole 462 in the body of the upper muffler
cover 46, so that the degree of superheat of intake refrigerant can
be kept proper with high accuracy.
[0096] The compressor described in the first to sixth embodiments
is a two-cylinder type rotary compressor provided with two
compression sections. However, the present invention is not limited
to this type, and can be applied to one-cylinder type rotary
compressor provided with one compression section.
[0097] Next, a seventh embodiment of the present invention is
explained with reference to FIGS. 7A and 7B. FIG. 7A is a general
sectional view of a rotary compressor in accordance with the
seventh embodiment of the present invention, and FIG. 7B is a
configuration diagram of a refrigeration cycle in accordance with
the seventh embodiment of the present invention. In FIG. 7A, the
same reference symbols are applied to elements that are the same as
those in FIG. 1A showing the first embodiment, and the detailed
explanation thereof is omitted.
[0098] As shown in FIG. 7A, the compressor 1 of the seventh
embodiment is a rotary compressor provided with two compression
sections like the compressor of the first embodiment. Herein,
points different from the compressor of the first embodiment are
explained.
[0099] The compressor of the first embodiment has two compression
sections connected in parallel with respect to the flow of
refrigerant. By contrast, the compressor 1 of the seventh
embodiment has two compression sections 3L and 3H connected in
series with respect to the flow of refrigerant by connecting the
discharge side of the low stage side compression section 3L to the
suction side of the high stage side compression section 3H by using
an intermediate interconnection pipe 82.
[0100] The suction side of the low stage side compression section
3L is connected to the accumulator 7 via the low-pressure suction
pipe 71. Thereby, the low-pressure refrigerant sucked into the low
stage side compression section 3L after passing through the
accumulator 7 is compressed to an intermediate pressure in the low
stage side compression section 3L, then being sucked into the high
stage side compression section 3H through the intermediate
interconnection pipe 82, and is compressed from the intermediate
pressure to a high pressure in the high stage side compression
section 3H.
[0101] Further, the compressor 1 has an intermediate-pressure
suction pipe 81, which is connected to an injection line 991,
described later, to suck an intermediate-pressure injection
refrigerant, in addition to the low-pressure suction pipe 71 for
sucking the low-pressure refrigerant into the low stage side
compression section 3L.
[0102] The intermediate-pressure suction pipe 81 is connected to
the intermediate interconnection pipe 82 that connects the
discharge side of the low stage side compression section 3L to the
suction side of the high stage side compression section 3H.
Thereby, the injection refrigerant is sucked into the high stage
side compression section 3H bypassing the low stage side
compression section 3L.
[0103] In this two-stage compression type rotary compressor 1, the
refrigerant compressed in the high stage side compression section
3H is discharged into the closed container 2 after passing through
the upper muffler chamber 56, and further discharged to the outside
of the closed container 2 through the discharge pipe 26 after
passing through the surroundings of the motor 6.
[0104] The upper muffler discharge hole 462 is open toward the
inner peripheral surface of the closed container 2 so that the
refrigerant discharged from the upper muffler chamber 56 is sprayed
directly toward the inner peripheral surface of the closed
container 2. Further, the discharge temperature sensor 20 is
mounted on the outer peripheral surface of the closed container 2
opposed to the sprayed portion.
[0105] The configuration of the upper muffler cover 46 is the same
as that of the fifth embodiment. However, the upper muffler cover
46 may have the same configuration as that of the first to fourth
embodiments or the sixth embodiment.
[0106] As shown in FIG. 7B, the refrigeration cycle in the seventh
embodiment has a basic cycle formed by connecting the compressor 1,
the condenser 91, the basic cycle expansion mechanism 93, and the
evaporator 92 in succession by using the line 99. This basic cycle
is provided with a temperature sensor Te for detecting the
temperature of injection refrigerant and a temperature sensor Tf
for detecting the refrigerant temperature on the outlet side of an
internal heat exchanger 95 in addition to the temperature sensors
Ta to Td having been explained with reference to FIG. 1C.
[0107] Since the operation in this basic cycle is the same as that
in the refrigeration cycle of the first embodiment, the operation
of gas injection relating to the seventh embodiment is explained
below.
[0108] Some of the refrigerant is branched from the basic cycle as
an injection refrigerant by a branch pipe 96 provided behind the
outlet of the condenser 91, and is further decompressed by an
injection expansion mechanism 94. The decompressed injection
refrigerant is heat-exchanged with the branched refrigerant of
basic cycle by the internal heat exchanger 95.
[0109] The injection refrigerant having enthalpy increased by the
heat exchange in the internal heat exchanger 95 is injected into
the intermediate-pressure suction pipe 81 through the injection
line 991. At this time, the injection refrigerant is not gasified
completely and some thereof is used as a liquid by controlling the
throttle amount of the injection expansion mechanism 94, by which
the compressor 1 is cooled to improve the compression efficiency of
the compressor 1.
[0110] On the other hand, the enthalpy of refrigerant in the basic
cycle is decreased by the heat exchange in the internal heat
exchanger 95, and further the enthalpy thereof is increased by the
evaporator 92 after the refrigerant has been decompressed by the
basic cycle expansion mechanism 93. In this state, the refrigerant
in the basic cycle is sucked into the low-pressure suction pipe 71
after passing through the accumulator 7 of the compressor 1.
[0111] In this cycle using gas injection, as compared with the
cycle without gas injection shown in the first embodiment, the heat
releasing capacity is increased by the increase in refrigerant
circulation flow rate in the condenser 91, and the heat absorbing
capacity is increased by the decrease in enthalpy of the
refrigerant at the evaporator inlet in the evaporator 92, by which
the capacity as the refrigeration cycle is increased.
[0112] In the case where the evaporator 92 is arranged in an indoor
unit, the indoor air is cooled, so that the heat pump system serves
as a cooler, and in the case where the condenser 91 is arranged in
an indoor unit, the indoor air is heated, so that the heat pump
system serves as a heater. Though not shown in FIG. 7B, if a line
and a selector valve for exchanging the evaporator and the
condenser for each other are added to the compressor 1, the
internal heat exchanger 95 and the basic cycle expansion mechanism
93, the heat pump system can be used as a cooling and heating
machine. Also, if the condenser 91 is heat-exchanged with water for
hot-water supply, the heat pump system serves as a water
heater.
[0113] Also, the heat pump system of this embodiment is provided
with the control unit 97 for keeping the refrigerant in the
refrigeration cycle in a proper state.
[0114] The control unit 97 sends a signal for detecting at least
condenser refrigerant temperature, evaporator refrigerant
temperature, compressor discharge temperature, and internal heat
exchanger outlet temperature of injection refrigerant and
controlling the throttle amount of the basic cycle expansion
mechanism 93, the throttle amount of the injection expansion
mechanism, and the number of revolutions of the compressor 1 to
keep the refrigerant circulating amount of refrigeration cycle
proper with respect to the capacity required in the heat pump
system, and further to keep the state of refrigerant in the
refrigeration cycle, that is, the degree of supercooling of
refrigerant at the outlet of the condenser 91 in the refrigeration
cycle, the degree of superheat of refrigerant in the low-pressure
suction pipe 71 of the compressor 1, and the dryness or the degree
of superheat of refrigerant in the intermediate-pressure suction
pipe 81 proper.
[0115] In the present invention, the discharge temperature sensor
20 is mounted on the outer peripheral surface of the closed
container 2 opposed to a portion in which the refrigerant
compressed in the closed container 2 of the compressor 1 comes into
contact with the closed container 2 before passing through the
surroundings of the motor 6, by which the refrigerant temperature
before heat exchange with the motor 6, that is, immediately after
the discharge from the high stage side compression section 3H can
be detected almost directly. Therefore, the throttle amount of the
basic cycle expansion mechanism 93, the throttle amount of the
injection expansion mechanism 94, and the number of revolutions of
the compressor 1 can be controlled based on the detected
temperature, and the dryness or the degree of superheat of
refrigerant sucked into the high stage side compression section 3H
of the compressor 1 can be kept more proper.
[0116] Next, an eighth embodiment of the present invention is
explained with reference to FIG. 8. FIG. 8 is a configuration
diagram of a refrigeration cycle in accordance with the eighth
embodiment of the present invention. The compressor of this
embodiment is the same as that of the seventh embodiment shown in
FIG. 7A.
[0117] As shown in FIG. 8, the refrigeration cycle in the eighth
embodiment has a basic cycle formed by connecting the compressor 1,
the condenser 91, a first expansion mechanism 931, an
intermediate-pressure gas-liquid separator 98, a second expansion
mechanism 932, and the evaporator 92 in succession by using the
line 99. In FIG. 8, reference symbol Tg denotes a temperature
sensor for detecting the refrigerant temperature on the downstream
side of the first expansion mechanism 931.
[0118] Since the operation in this basic cycle is the same as that
in the refrigeration cycle of the first embodiment, the operation
of gas injection relating to the eighth embodiment is explained
below.
[0119] The refrigerant having become in a two-phase state by being
decompressed to an intermediate pressure by the first expansion
mechanism 931 is separated into a gas refrigerant and a liquid
refrigerant by the intermediate-pressure gas-liquid separator 98.
The gas refrigerant is injected into the intermediate-pressure
suction pipe 81 of the compressor 1 as an injection refrigerant
through the injection line 991.
[0120] At this time, an injection liquid flow control mechanism 942
is opened by a proper amount to mix the liquid refrigerant in some
of the injection refrigerant, by which the compressor 1 is cooled
to improve the compression efficiency of the compressor 1.
[0121] On the other hand, the enthalpy of liquid refrigerant in the
intermediate-pressure gas-liquid separator 98 is increased by the
evaporator 92 after the liquid refrigerant has been decompressed by
the second expansion mechanism 932. Then, the liquid refrigerant is
sucked into the low-pressure suction pipe 71 after passing through
the accumulator 7 of the compressor 1.
[0122] In this gas injection cycle, as in the case of the internal
heat exchange system, as compared with the cycle without gas
injection, the heat releasing capacity is increased by the increase
in refrigerant circulation flow rate in the condenser 91, and the
heat absorbing capacity is increased by the decrease in enthalpy of
the refrigerant at the evaporator inlet in the evaporator 92, by
which the capacity as the refrigeration cycle is increased.
[0123] In the case where the evaporator 92 is arranged in an indoor
unit, the indoor air is cooled, so that the heat pump system serves
as a cooler, and in the case where the condenser 91 is arranged in
an indoor unit, the indoor air is heated, so that the heat pump
system serves as a heater. Though not shown in FIG. 8, if a line
and a selector valve for exchanging the evaporator and the
condenser for each other are added, the heat pump system can be
used as a cooling and heating machine. Also, if the condenser 91 is
heat-exchanged with water for hot-water supply, the heat pump
system serves as a water heater.
[0124] Also, the heat pump system of this embodiment is provided
with the control unit 97 for keeping the refrigerant in the
refrigeration cycle in a proper state.
[0125] The control unit 97 sends a signal for detecting at least
condenser refrigerant temperature, evaporator refrigerant
temperature, compressor discharge temperature, and injection
refrigerant temperature and controlling the throttle amount of the
first expansion mechanism 931, the throttle amount of the second
expansion mechanism 932, an injection gas refrigerant flow control
mechanism 941, the injection liquid refrigerant flow control
mechanism 942, and the number of revolutions of the compressor 1 to
keep the refrigerant circulating amount of refrigeration cycle
proper with respect to the capacity required in the heat pump
system, and further to keep the state of refrigerant in the
refrigeration cycle, that is, the degree of supercooling of
refrigerant at the outlet of the condenser 91 in the refrigeration
cycle, the degree of superheat of refrigerant in the low-pressure
suction pipe 71 of the compressor 1, and the dryness or the degree
of superheat of refrigerant in the intermediate-pressure suction
pipe 81 proper.
[0126] In the present invention, the compressor 1 is the same as
the compressor of the seventh embodiment, and the discharge
temperature sensor 20 is mounted on the outer peripheral surface of
the closed container 2 opposed to a portion in which the
refrigerant before passing through the surroundings of the motor 6
comes into contact with the closed container 2, by which the
refrigerant temperature before heat exchange with the motor 6, that
is, immediately after the discharge from the high stage side
compression section 3H can be detected almost directly. Therefore,
the throttle amount of the first expansion mechanism 931, the
throttle amount of the second expansion mechanism 932, the
injection gas refrigerant flow control mechanism 941, the injection
liquid refrigerant flow control mechanism 942, and the number of
revolutions of the compressor 1 can be controlled based on the
detected temperature, and the dryness or the degree of superheat of
refrigerant sucked into the high stage side compression section 3H
of the compressor 1 can be kept more proper.
[0127] The present application is based on, and claims priority
from, Japanese Applications Serial Number JP2006-266429, filed Sep.
29, 2006 and JP2007-126573, filed May 11, 2007 the disclosure of
which is hereby incorporated by reference herein in its
entirety.
* * * * *