FORM 2
THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENTS RULES, 2003
COMPLETE SPECIFICATION
[See section 10, Rule 13]
AIR-CONDITIONING APPARATUS;
MITSUBISHI ELECTRIC CORPORATION, A CORPORATION ORGANISED AND
EXISTING UNDER THE LAWS OF JAPAN, WHOSE ADDRESS IS 7-3,
MARUNOUCHI 2-CHOME, CHIYODA-KU, TOKYO 1008310, JAPAN
THE FOLLOWING SPECIFICATION PARTICULARLY DESCRIBES THE
INVENTION AND THE MANNER IN WHICH IT IS TO BE PERFORMED.
2
DESCRIPTION
Technical Field
[0001]
The present disclosure relates to an air-conditioning apparatus and, more
specifically, to damage prevention 5 of a compressor.
Background Art
[0002]
In the case of relocating or disposing of a split air-conditioning apparatus, a
forced cooling operation called a pump-down operation has been performed.
10 Refrigerant in a refrigerant circuit is collected in an outdoor unit through such a pumpdown
operation. If a large amount of air is mixed in a refrigerant circuit during a
pump-down operation, air is compressed in a compressor disposed in an outdoor
unit, and refrigerating machine oil and air having a high temperature and a high
pressure are mixed. As a result, the pressure in the compressor increases rapidly,
15 and thus a casing of the compressor may be damaged.
[0003]
Patent Literature 1 describes a configuration in which a relief valve is installed
in a hole in communication with a discharge chamber of a compressor and the relief
valve is covered with a rupture disk. The relief valve is configured to open when a
20 pressure higher than or equal to a predetermined pressure acts on the relief valve
from the discharge chamber. The rupture disk is configured to operate and rupture
at a pressure lower than a pressure at which the relief valve operates. If the
compressor operates abnormally and the pressure in the discharge chamber of the
compressor becomes a pressure higher than or equal to the predetermined pressure,
25 the relief valve opens and the rupture disk ruptures. As a result, the refrigerant in
the discharge chamber is released into the atmosphere, and the pressure in the
compressor is reduced. Thus, the compressor is prevented from being broken
because of high pressure.
Citation List
30 Patent Literature
3
[0004]
Patent Literature 1: Japanese Unexamined Patent Application Publication No.
2004-353578
Summary of Invention
5 Technical Problem
[0005]
The relief valve described in Patent Literature 1 includes a spring, and a gas
storage chamber is formed between the relief valve and the rupture disk. For this
reason, to cause the inside and the outside of the compressor to communicate with
10 each other, a valve body has to be pushed up against the urging force of the spring.
Thus, the configuration described in Patent Literature 1 has a problem of not being
capable of dealing with rapid pressure increases that may occur during a pump-down
operation.
[0006]
15 The present disclosure is made to solve such a problem, and an object of the
present disclosure is to provide an air-conditioning apparatus in which a casing of a
compressor is not damaged even if the pressure in the compressor increases rapidly.
Solution to Problem
[0007]
20 An air-conditioning apparatus according to an embodiment of the present
disclosure includes an outdoor unit including a compressor and an outdoor heat
exchanger, an indoor unit including an indoor heat exchanger, and an opening valve
for guiding gas in the compressor to outside. The compressor, the outdoor heat
exchanger, and the indoor heat exchanger are connected by refrigerant pipes and
25 form a refrigerant circuit. The opening valve includes a cylindrical portion and a
closing portion that has a plate-like shape. A first end portion of the cylindrical
portion is open, and a second end portion of the cylindrical portion is closed by the
closing portion. The cylindrical portion is in communication with the compressor via
the first end portion. The opening valve is configured in such a manner that, when a
30 pressure in the compressor reaches an opening pressure that is higher than a proof
4
pressure in the compressor, the proof pressure being set to be higher than a design
pressure in the air-conditioning apparatus, and that is lower than a failure pressure at
which the compressor is damaged, an opening is provided in the closing portion or in
a boundary portion between the cylindrical portion and the closing portion.
Advantageous Effects 5 of Invention
[0008]
In the air-conditioning apparatus according to an embodiment of the present
disclosure, the first end portion of the cylindrical portion of the opening valve is open,
the cylindrical portion is in communication with the compressor via the first end
10 portion, and the opening valve opens when the pressure in the compressor reaches
the opening pressure that is higher than the proof pressure in the compressor and
that is lower than the failure pressure in the compressor. Thus, even if the pressure
in the compressor increases rapidly, it is possible to prevent the casing of the
compressor from being damaged.
15 Brief Description of Drawings
[0009]
[Fig. 1] Fig. 1 is a diagram of a refrigeration cycle of an air-conditioning
apparatus according to Embodiment 1 of the present disclosure.
[Fig. 2] Fig. 2 is a schematic diagram of a compressor of the air-conditioning
20 apparatus according to Embodiment 1 of the present disclosure.
[Fig. 3] Fig. 3 is a diagram illustrating a shape of an opening valve of the airconditioning
apparatus according to Embodiment 1 of the present disclosure.
[Fig. 4] Fig. 4 is a graph illustrating pressure variations in the compressor of the
air-conditioning apparatus according to Embodiment 1 of the present disclosure.
25 [Fig. 5] Fig. 5 is a graph illustrating the relationship between the rotation
frequency of the compressor and the pressure increase rate in the compressor on the
basis of test results illustrated in Table 1.
[Fig. 6] Fig. 6 is a graph illustrating the relationship between the inside diameter
of a cylindrical portion of the opening valve and a pressure release rate on the basis
30 of test results illustrated in Table 2.
5
[Fig. 7] Fig. 7 is a graph illustrating the relationship between the maximum
pressure in the compressor and the ratio between the thickness of a closing portion
and the inside diameter of the cylindrical portion in the opening valve on the basis of
test results illustrated in Table 3.
[Fig. 8] Fig. 8 is a diagram illustrating another example of the 5 opening valve of
the air-conditioning apparatus.
[Fig. 9] Fig. 9 is a diagram illustrating another example of the opening valve of
the air-conditioning apparatus.
[Fig. 10] Fig. 10 is a schematic diagram of a compressor of an air-conditioning
10 apparatus according to Embodiment 2 of the present disclosure.
[Fig. 11] Fig. 11 is a diagram of a refrigeration cycle of an air-conditioning
apparatus according to Embodiment 3 of the present disclosure.
Description of Embodiments
[0010]
15 Embodiments of an air-conditioning apparatus in the present disclosure will be
described in detail below with reference to the drawings. The present disclosure is
not limited by the embodiments described below. The sizes and shapes of the
components in the drawings below may differ from those of an actual apparatus.
[0011]
20 Embodiment 1
Fig. 1 is a diagram of a refrigeration cycle of an air-conditioning apparatus
according to Embodiment 1 of the present disclosure. An air-conditioning apparatus
1 includes an outdoor unit 10 and an indoor unit 20. The outdoor unit 10 includes a
compressor 11, a muffler 12, a four-way switching valve 13, an outdoor heat
25 exchanger 14, a refrigerant pressure reducing device 15, a liquid stop valve 16, a gas
stop valve 17, and an outdoor fan 18. The indoor unit 20 includes an indoor heat
exchanger 21 and an indoor fan 22. The compressor 11, the muffler 12, the fourway
switching valve 13, the outdoor heat exchanger 14, the refrigerant pressure
reducing device 15, the liquid stop valve 16, the indoor heat exchanger 21, and the
6
gas stop valve 17 are connected by refrigerant pipes 30 in this order and form a
refrigerant circuit.
[0012]
The compressor 11 compresses and discharges suctioned refrigerant. The
compressor 11 varies the volume in the compressor 11, that 5 is, the amount of
refrigerant sent per unit time by freely varying an operating frequency with, for
example, an inverter circuit. The muffler 12 is disposed at a refrigerant pipe that is
connected to a discharge port of the compressor 11. The muffler 12 reduces
refrigerant pulsation. The four-way switching valve 13 is a valve that switches
10 between a refrigerant flow in a cooling operation and a refrigerant flow in a heating
operation. Fig. 1 illustrates the refrigerant cycle in a cooling operation. In Fig. 1,
the refrigerant circuit in a heating operation is partly omitted.
[0013]
The outdoor heat exchanger 14 exchanges heat between refrigerant and
15 outdoor air. The outdoor heat exchanger 14 is used as an evaporator in a heating
operation and evaporates and gasifies refrigerant. In addition, the outdoor heat
exchanger 14 is used as a condenser in a cooling operation and condenses and
liquefies refrigerant. The refrigerant pressure reducing device 15 decompresses and
expands refrigerant. For example, in the case of the refrigerant pressure reducing
20 device 15 including an electronic expansion valve, the opening degree of the
refrigerant pressure reducing device 15 is controlled by instructions from a controller,
which is not illustrated. The outdoor air that exchanges heat with refrigerant in the
outdoor heat exchanger 14 is sent into the outdoor heat exchanger 14 by the outdoor
fan 18.
25 [0014]
The indoor heat exchanger 21 exchanges heat between air-conditioning target
air and refrigerant. The indoor heat exchanger 21 is used as a condenser in a
heating operation and condenses and liquefies refrigerant. In addition, the indoor
heat exchanger 21 is used as an evaporator in a cooling operation and evaporates
7
and gasifies refrigerant. The air that exchanges heat with refrigerant in the indoor
heat exchanger 21 is sent into the indoor heat exchanger 21 by the indoor fan 22.
[0015]
Fig. 2 is a schematic diagram of the compressor of the air-conditioning
apparatus according to Embodiment 1 of the present disclosure. 5 The compressor 11
includes a casing 110 and an opening valve 40. The casing 110 includes a top
surface portion 110A and a drum 110B. The refrigerant pipe 30 is connected to the
top surface portion 110A. The opening valve 40 is a component for guiding the gas
in the compressor 11 to the outside. The opening valve 40 is a component separate
10 from the refrigerant pipe 30 and is disposed at the head plate of the top surface
portion 110A.
[0016]
Fig. 3 is a diagram illustrating a shape of the opening valve of the airconditioning
apparatus according to Embodiment 1 of the present disclosure. The
15 opening valve 40 includes a cylindrical portion 41 and a closing portion 42, which has
a plate-like shape. The opening valve 40 has an overall cylindrical shape. Fig. 3
illustrates a longitudinal section of the opening valve 40 taken along the axis of the
cylindrical portion 41. A first end portion 41A of the cylindrical portion 41 is open,
and a second end portion 41B of the cylindrical portion 41 is closed by the closing
20 portion 42. The closing portion 42 has a flat plate-like shape.
[0017]
As illustrated in Fig. 2, the opening valve 40 is disposed at the compressor 11
in such a manner that the first end portion 41A of the cylindrical portion 41 faces and
is open to the inside of the compressor 11 and that the second end portion 41B of the
25 cylindrical portion 41 faces the outside of the compressor 11. The cylindrical portion
41 is in communication with the compressor 11 via the first end portion 41A. This
configuration enables the gas in the compressor 11 to flow into the cylindrical portion
41.
[0018]
8
Fig. 4 is a graph illustrating pressure variations in the compressor of the airconditioning
apparatus according to Embodiment 1 of the present disclosure. The
function of the opening valve 40 is described with reference to Fig. 4. In the graph in
Fig. 4, the vertical axis represents a pressure P in the compressor 11, and the
horizontal axis represents a time T. The unit of the pressure P is "5 MPa", and the unit
of the time T is "sec", that is, seconds. Pcomp is a design pressure in the airconditioning
apparatus 1. P1max is a proof pressure in the compressor 11. The
proof pressure P1max in the compressor 11 is about three times higher than the
design pressure Pcomp in the air-conditioning apparatus 1. The compressor 11 is
10 designed to guarantee the proof pressure P1max. That is, when a pressure applied
to the inside of the compressor 11 is lower than the proof pressure P1max, the
compressor 11 is guaranteed to operate normally. P2max is a failure pressure in the
compressor 11. The failure pressure P2max in the compressor 11 is a pressure at
which the compressor 11 is damaged. The failure pressure P2max in the
15 compressor 11 is a value with a tolerance that deviates from the proof pressure
P1max toward a higher pressure. That is, when a pressure higher than or equal to
the failure pressure P2max is applied to the inside of the compressor 11, the
compressor 11 may be damaged and may not operate normally.
[0019]
20 In a pump-down operation, a forced refrigerant operation is performed with the
liquid stop valve 16 completely closed and the gas stop valve 17 completely open to
collect refrigerant in the indoor unit 20 illustrated in Fig. 1 into the outdoor unit 10. In
this case, for example, if a cooling operation is performed with the outdoor unit 10 and
the indoor unit 20 separated from each other in advance and with the gas stop valve
25 17 completely open, a large amount of air is mixed in the refrigerant circuit. As a
result, air is compressed in the compressor 11, and the pressure P in the compressor
11 rapidly increases to a pressure higher than the failure pressure P2max. Thus, the
compressor 11 may be damaged.
[0020]
9
A solid line L1 in Fig. 4 represents, in a pump-down operation performed in the
air-conditioning apparatus 1, how the pressure P in the compressor 11 lower than the
design pressure Pcomp rapidly increases to a pressure higher than the design
pressure Pcomp and further increases to a pressure higher than the proof pressure
P1max because of a large amount of air being mixed in the refrigerant 5 circuit. In this
case, unless the high-pressure gas in the compressor 11 is discharged to the outside
of the compressor 11, as represented by a short-dashed line L2, the pressure P in the
compressor 11 continues to increase rapidly and becomes higher than the failure
pressure P2max.
10 [0021]
For this reason, in the configuration in Embodiment 1, when the pressure P in
the compressor 11 rapidly increases, the high-pressure gas in the compressor 11 is
discharged through the opening valve 40. The opening valve 40 is configured to
begin to open when an opening pressure Pp, which is set to a value larger than the
15 proof pressure P1max in the compressor 11 and smaller than the failure pressure
P2max in the compressor 11, is applied to the opening valve 40. That is, when the
closing portion 42 is pressed at the pressure of the gas that has flowed into the
cylindrical portion 41 and the pressure of the gas becomes higher than the proof
pressure P1max and reaches the opening pressure Pp because of an increase in the
20 pressure in the compressor 11, an opening is provided in the closing portion 42 or in a
boundary portion between the cylindrical portion 41 and the closing portion 42.
Then, the cylindrical portion 41 becomes an open passage through which the gas in
the compressor 11 is guided to the outside of the compressor 11.
[0022]
25 In addition, the opening valve 40 is configured in such a manner that the open
passage through which the gas in the compressor 11 is guided to the outside of the
compressor 11 is formed in the opening valve 40 before the pressure P in the
compressor 11 becomes higher than the proof pressure P1max and reaches the
failure pressure P2max. In the example illustrated in Fig. 4, the time from when the
30 pressure P in the compressor 11 becomes higher than the proof pressure P1max to
10
when the pressure P in the compressor 11 reaches the failure pressure P2max is (t2 -
t1) sec. In this case, in Embodiment 1, the opening valve 40 is configured in such a
manner that the time from when the opening valve 40 begins to open to when the
cylindrical portion 41 is used as the open passage is shorter than (t2 - t1) sec. With
this configuration, the pressure P in the compressor 11 that increases 5 rapidly and
becomes higher than the proof pressure P1max drops without reaching the failure
pressure P2max as represented by a long-dashed line L3 in Fig. 4.
[0023]
In Embodiment 1, as illustrated in Fig. 3, the opening valve 40 is composed of
10 the cylindrical portion 41 and the closing portion 42, and the first end portion 41A of
the cylindrical portion 41 is in communication with the compressor 11. Hereinafter,
the inside diameter of the cylindrical portion 41 of the opening valve 40 and the
thickness of the closing portion 42 are described. Table 1 is a table illustrating the
relationship between the rotation frequency of the compressor 11 and the pressure
15 increase rate in the compressor 11 in the case of the compressor 11 including the
casing 110 in which the drum 110B has an inside diameter of 107 mm and a thickness
of 2.6 mm. Fig. 5 is a graph illustrating the relationship between the rotation
frequency of the compressor 11 and the pressure increase rate in the compressor 11
on the basis of test results illustrated in Table 1. As illustrated in Table 1 and Fig. 5,
20 in the case of a typical rotation frequency of a compressor of 60 rps, the pressure
increase rate is about 200 MPa/sec. To release the pressure in the compressor 11
without damaging the casing of the compressor 11, the pressure release rate has to
be higher than the pressure increase rate.
[0024]
25 [Table 1]
Rotation
Frequency
[rps]
Pressure Increase Rate
[MPa/sec]
60 228.6
60 238.1
60 240.0
60 205.9
11
60 245.2
60 207.7
60 290.3
80 400.0
80 476.2
100 555.6
100 625.0
100 625.0
100 454.5
100 500.0
100 714.3
100 555.6
100 622.0
100 444.4
100 426.7
100 683.3
100 666.7
100 600.0
100 614.3
100 625.0
100 555.6
100 666.7
100 830.8
100 609.8
100 457.1
100 415.4
100 500.0
100 816.3
115 588.2
115 769.2
[0025]
Table 2 is a table illustrating the relationship between the inside diameter of the
opening valve 40 and the pressure release rate in the compressor 11 in the case of a
test of the compressor 11 including the casing 110 in which the 5 drum 110B has an
inside diameter of 107 mm and a thickness of 2.6 mm with the inside diameter of the
cylindrical portion 41 of the opening valve 40 varied. Fig. 6 is a graph illustrating the
relationship between the inside diameter of the cylindrical portion 41 of the opening
valve 40 and the pressure release rate on the basis of test results illustrated in Table
12
2. In the graph in Fig. 6, the vertical axis represents the pressure release rate, and
the horizontal axis represents the inside diameter of the cylindrical portion 41.
[0026]
[Table 2]
Inside Diameter of Opening valve
d [mm]
Pressure Release Rate
[MPa/sec]
19.0 760.0
19.0 880.0
11.1 307.4
11.1 193.3
11.1 162.2
10.0 186.2
15.0 376.5
13.0 300.0
11.1 276.5
16.6 273.5
15.0 411.8
11.1 250.0
12.0 420.0
12.0 505.3
12.0 390.9
12.0 390.0
12.0 361.9
12.0 410.5
12.0 295.2
12.0 381.8
12.0 357.1
12.0 333.3
12.0 416.7
12.0 236.4
25.0 1800.0
15.0 480.0
20.0 933.3
5
[0027]
As illustrated in Fig. 6, when the inside diameter of the cylindrical portion 41 is
10 mm or more, the pressure release rate tends to be higher than 200 MPa/sec. For
this reason, when the inside diameter of the cylindrical portion 41 is about one-tenth
10 or more of the inside diameter of the drum 110B, the pressure release rate is higher
13
than 200 MPa/sec and thus can be higher than the pressure increase rate. On the
other hand, the initial energy of jets generated when the casing of the compressor 11
or the opening valve 40 is damaged because of internal pressure is, under the
condition of the same internal pressure, in proportion to the length of a crack caused
in the casing of the compressor 11 or the damaged portion of the opening 5 valve 40 in
the early stage of damage. For example, if a straight crack is caused in the closing
portion 42 of the opening valve 40, the ratio between the damage of the casing of the
compressor 11 and the initial energy generated when the opening valve 40 opens is
(the length of a crack caused in the casing of the compressor 11 because of the
10 damage of the casing of the compressor 11):(the diameter of the opening valve 40).
That is, the amount of energy generated in a pressure release can be reduced as the
diameter of the opening valve 40 is reduced. On the basis of these test results and
the consideration, the inside diameter of the cylindrical portion 41 of Embodiment 1 is
set to about one-tenth or more of the inside diameter of the drum 110B of the casing
15 110 of the compressor 11 in Fig. 2. More preferably, the inside diameter of the
cylindrical portion 41 is one-tenth or more of the inside diameter of the drum 110B of
the casing 110 of the compressor 11, and the upper limit is set on the basis of the
allowable amount of energy generated in a pressure release.
[0028]
20 Table 3 is a table illustrating the relationship between the closing portion 42 of
the opening valve 40, the inside diameter of the opening valve 40, and the maximum
pressure in the compressor 11 in the case of a test of the above compressor 11 with
the thickness of the closing portion 42 of the opening valve 40 and the inside
diameter of the cylindrical portion 41 varied. Fig. 7 is a graph illustrating the
25 relationship between the maximum pressure in the compressor 11 and the ratio of the
thickness of the closing portion 42 to the inside diameter of the cylindrical portion 41
in the opening valve 40 on the basis of test results illustrated in Table 3. In the graph
in Fig. 7, the vertical axis represents the maximum pressure in the compressor 11,
and the horizontal axis represents the ratio of the thickness of the closing portion 42
30 to the inside diameter of the cylindrical portion 41.
14
[0029]
[Table 3]
Inside Diameter of
Cylindrical Portion
d [mm]
Thickness of Closing
Portion
t [mm]
Thickness of Closing
Portion/Inside
Diameter of
Cylindrical Portion
t/d
Maximum Pressure
[MPa]
11.1 0.3 0.027 19.1
13.0 0.3 0.023 12.7
11.1 0.3 0.027 17.0
11.1 0.3 0.027 17.4
11.1 0.3 0.027 17.8
11.1 0.3 0.027 17.0
12.0 0.3 0.025 17.6
25.0 0.6 0.024 15.4
15.0 0.4 0.027 17.4
20.0 0.5 0.025 15.6
[0030]
On the basis of the test results, the thickness of the closing 5 portion 42 of the
opening valve 40 of Embodiment 1 is set to about one-tenth of the thickness of the
casing 110 of the compressor 11 illustrated in Fig. 2. More preferably, the thickness
of the closing portion 42 is one-tenth or more of the thickness of the casing 110 of the
compressor 11, and the upper limit is set on the basis of the maximum pressure
10 determined by the ratio between the thickness of the closing portion 42 and the inside
diameter of the cylindrical portion 41. In addition, the thickness of the cylindrical
portion 41 is larger than the thickness of the closing portion 42. The above
configuration enables the above function of the opening valve 40 to be achieved.
[0031]
15 According to Embodiment 1, when the pressure in the compressor 11 is lower
than the proof pressure P1max, the opening valve 40 is closed by the closing portion
42. When the pressure in the compressor 11 becomes higher than the proof
pressure P1max and reaches the opening pressure Pp, the opening valve 40 opens.
Then, the open passage is reliably formed before the pressure in the compressor 11
20 reaches the failure pressure P2max. Thus, it is possible to prevent the compressor
15
11 from being damaged when the pressure in the compressor 11 increases rapidly
without affecting the function and the performance of the normal cooling and heating
operations of the air-conditioning apparatus 1. In particular, even if the increase rate
of the pressure P in the compressor 11 is higher than a transmission rate at which
high-pressure gas reaches a component other than the compressor 5 11 in the
refrigerant circuit, it is possible to prevent the casing 110 of the compressor 11 from
being damaged.
[0032]
As the thickness of the cylindrical portion 41 of the opening valve 40 is larger
10 than the thickness of the closing portion 42, the cylindrical portion 41 in the shape of
the open passage is maintained after the opening valve 40 opens in response to a
rapid increase in the pressure in the compressor 11.
[0033]
It can be also proposed that a temperature sensor or a pressure sensor be
15 disposed at the air-conditioning apparatus 1 and the shutdown of the compressor 11
be controlled on the basis of detection results from these sensors. However, under
such control, it is not possible to deal with the occurrence of a phenomenon such as a
deviation from a predetermined value set as a criterion for the shutdown of the
compressor 11 or to deal with pressure increases at a rate higher than the reaction
20 rates of the sensors, and thus the compressor 11 may be damaged. On the other
hand, in Embodiment 1, the opening pressure Pp in the opening valve 40 is set to a
value larger than the proof pressure P1max and smaller than the failure pressure
P2max. In addition, the open passage is formed in the opening valve 40 before the
pressure P in the compressor 11 becomes higher than the proof pressure P1max and
25 reaches the failure pressure P2max. Thus, according to Embodiment 1, it is
possible to deal with a rapid increase in the pressure in the compressor 11 and
prevent the compressor 11 from being damaged.
[0034]
In addition, according to Embodiment 1, the thickness of the cylindrical portion
30 41 is larger than the thickness of the closing portion 42. Thus, an opening is
16
provided in the closing portion 42 or at a boundary between the closing portion 42
and the cylindrical portion 41, and the cylindrical portion 41 in the shape of the open
passage is maintained when high-pressure gas is discharged to the outside of the
compressor 11.
5 [0035]
The shape of the closing portion 42 of the opening valve 40 is not limited to the
shape illustrated in Fig. 3. Figs. 8 and 9 are diagrams each illustrating another
example of the opening valve of the air-conditioning apparatus. An opening valve 50
illustrated in Fig. 8 includes a cylindrical portion 51 and a closing portion 52. A first
10 end portion 51A of the cylindrical portion 51 is open, and a second end portion 51B is
closed by the closing portion 52. The closing portion 52 is formed to curve convexly
toward the inside of the cylindrical portion 51. Also in the example in Fig. 8, the
inside diameter of the cylindrical portion 51 is set to about one-tenth of the inside
diameter of the drum 110B of the casing 110 of the compressor 11 in Fig. 2, and the
15 thickness of the closing portion 52 is set to about one-tenth of the thickness of the
casing 110 of the compressor 11 illustrated in Fig. 2. More preferably, the inside
diameter of the cylindrical portion 51 is set to one-tenth or more of the inside diameter
of the drum 110B of the casing 110 of the compressor 11, and the thickness of the
closing portion 52 is set to one-tenth or more of the thickness of the casing 110 of the
20 compressor 11. In addition, the thickness of the cylindrical portion 51 is larger than
the thickness of the closing portion 52.
[0036]
An opening valve 60 illustrated in Fig. 9 includes a cylindrical portion 61 and a
closing portion 62. A first end portion 61A of the cylindrical portion 61 is open, and a
25 second end portion 61B is closed by the closing portion 62. The closing portion 62 is
formed to curve convexly toward the outside of the cylindrical portion 61. Also in the
example in Fig. 9, the inside diameter of the cylindrical portion 61 is set to about onetenth
of the inside diameter of the drum 110B of the casing 110 of the compressor 11
in Fig. 2, and the thickness of the closing portion 62 is set to about one-tenth of the
30 thickness of the casing 110 of the compressor 11 illustrated in Fig. 2. More
17
preferably, the inside diameter of the cylindrical portion 61 is set to one-tenth or more
of the inside diameter of the drum 110B of the casing 110 of the compressor 11, and
the thickness of the closing portion 62 is set to one-tenth or more of the thickness of
the casing 110 of the compressor 11. In addition, the thickness of the cylindrical
portion 61 is larger than the thickness of the closing 5 portion 62.
[0037]
Embodiment 2
Fig. 10 is a schematic diagram of a compressor of an air-conditioning
apparatus according to Embodiment 2 of the present disclosure. In Fig. 10, the
10 components similar to the components of the compressor 11 of Embodiment 1 have
the same reference signs. As illustrated in Fig. 10, the opening valve 40 is a
component separate from the refrigerant pipe 30 and is disposed at a side face of the
drum 110B of the compressor 11. The first end portion 41A of the cylindrical portion
41 is in communication with the inside of the compressor 11. In the up-down
15 direction of the drum 110B, the opening valve 40 is disposed at a position higher than
the oil level of the refrigerating machine oil stored in a lower portion of the compressor
11. Embodiment 2 provides the effect similar to the effect of Embodiment 1
described above.
[0038]
20 Also in Embodiment 2, instead of the opening valve 40, the opening valve 50 in
Fig. 8 or the opening valve 60 in Fig. 9 may be disposed at a side face of the drum
110B of the compressor 11.
[0039]
Embodiment 3
25 Fig. 11 is a diagram of a refrigeration cycle of an air-conditioning apparatus
according to Embodiment 3 of the present disclosure. In Fig. 11, the components
similar to the components of the air-conditioning apparatus 1 of Embodiment 1 have
the same reference signs. A high-pressure region 70 is a region through which the
compressor 11 and the outdoor heat exchanger 14 are connected and into which the
30 high-pressure gas discharged from the compressor 11 flows. In Embodiment 3, in
18
the high-pressure region 70, the opening valve 40 similar to that described in
Embodiment 1 or 2 is disposed at the refrigerant pipe 30 via a branch pipe 80. The
branch pipe 80 is a branch pipe that branches off in three directions. A pipe
connected to the discharge port of the compressor 11, a pipe connected to the muffler
12, and the first end portion 41A illustrated in Fig. 3 of the opening 5 valve 40 are
connected to the branch pipe 80. Thus, similarly to Embodiment 1 and Embodiment
2 described above, the cylindrical portion 41 is in communication with the compressor
11 via the first end portion 41A. This configuration enables an open passage
through which high-pressure gas is released to the outside of the refrigerant circuit of
10 the air-conditioning apparatus 1 to be reliably formed.
[0040]
The high-pressure region 70 contains the muffler 12 and the four-way switching
valve 13. When the gas refrigerant discharged from the compressor 11 flows into
the high-pressure region 70, the pressure increase in the high-pressure region 70 is
15 not uniform. Thus, a portion of the refrigerant pipes 30 at which the opening valve
40 is disposed has to be adjusted on the basis of the refrigerant flow rate and the
distance from the discharge port of the compressor 11 to the portion at which the
opening valve 40 is disposed in such a manner that the pressure in the compressor
11 does not become higher than the proof pressure P1max before the pressure in the
20 portion at which the opening valve 40 is disposed reaches the opening pressure Pp.
[0041]
Meanwhile, as illustrated in Fig. 11, the high-pressure region 70 from the
compressor 11 to the outdoor heat exchanger 14 may contain the muffler 12. In a
cooling operation of the air-conditioning apparatus 1, the muffler 12 is one of
25 components closest to the compressor 11, and the components are positioned
downstream of the compressor 11 in the refrigerant circuit. In this case, in a forced
cooling operation in a pump-down operation, if high-pressure gas flows into the highpressure
region 70, the muffler 12 may also be damaged. For this reason, in
Embodiment 3, the opening valve 40 is disposed, via the branch pipe 80, at one of
30 the refrigerant pipes 30 that connects the compressor 11 and the muffler 12. That is,
19
in a pump-down operation, the opening valve 40 is disposed at a position upstream of
the muffler 12 in the refrigerant circuit.
[0042]
According to Embodiment 3, the opening valve 40 is disposed at the refrigerant
pipe 30 included in the refrigerant circuit. Thus, even if the 5 pressure increases
rapidly during a pump-down operation, it is possible to prevent the compressor 11
from being damaged without changing the existing configuration of the compressor
11.
[0043]
10 In addition, according to Embodiment 3, in a pump-down operation, the
opening valve 40 is disposed at a position upstream of the muffler 12 in the refrigerant
circuit. Thus, even if the pressure increases rapidly during a pump-down operation,
it is possible to prevent the muffler 12 in addition to the compressor 11 from being
damaged.
15 [0044]
Also in Embodiment 3, instead of the opening valve 40, the opening valve 50 in
Fig. 8 or the opening valve 60 in Fig. 9 may be installed at the branch pipe 80.
[0045]
The branch pipe 80 can be any branch pipe as long as a branch pipe branches
20 off in three or more directions and the opening valve 40 is disposed at a pipe
branching off from the branch pipe.
Reference Signs List
[0046]
1 air-conditioning apparatus 10 outdoor unit 11 compressor 12
25 muffler 13 four-way switching valve 14 outdoor heat exchanger 15
refrigerant pressure reducing device 16 liquid stop valve 17 gas stop valve 18
outdoor fan 20 indoor unit 21 indoor heat exchanger 22 indoor fan 30
refrigerant pipe 40 opening valve 41 cylindrical portion 41A first end portion
41B second end portion 42 closing portion 50 opening valve 51 cylindrical
30 portion 51A first end portion 51B second end portion 52 closing portion 60
20
opening valve 61 cylindrical portion 61A first end portion 61B second end
portion 62 closing portion 70 high-pressure region 80 branch pipe 110
casing 110A top surface portion 110B drum P pressure P1max proof
pressure P2max failure pressure Pp opening pressure
5
21
We Claim:
[Claim 1]
An air-conditioning apparatus, comprising:
an outdoor unit including a compressor and an outdoor 5 heat exchanger;
an indoor unit including an indoor heat exchanger; and
an opening valve for guiding gas in the compressor to outside,
the compressor, the outdoor heat exchanger, and the indoor heat exchanger
being connected by refrigerant pipes and forming a refrigerant circuit,
10 the opening valve including a cylindrical portion and a closing portion that has a
plate-like shape,
a first end portion of the cylindrical portion being open,
a second end portion of the cylindrical portion being closed by the closing
portion,
15 the cylindrical portion being in communication with the compressor via the first
end portion,
the opening valve being configured in such a manner that, when a pressure in
the compressor reaches an opening pressure that is higher than a proof pressure in
the compressor, the proof pressure being set to be higher than a design pressure in
20 the air-conditioning apparatus, and that is lower than a failure pressure at which the
compressor is damaged, an opening is provided in the closing portion or in a
boundary portion between the cylindrical portion and the closing portion.
[Claim 2]
The air-conditioning apparatus of claim 1, wherein
25 the proof pressure is set to three times higher than the design pressure, and
after the pressure in the compressor becomes higher than the proof pressure,
reaches the opening pressure, and the opening is provided, and before the pressure
in the compressor becomes higher than the proof pressure and reaches the failure
pressure, an open passage through which the gas in the compressor is guided to the
30 outside of the compressor is formed in the opening valve.
22
[Claim 3]
The air-conditioning apparatus of claim 2, wherein the cylindrical portion
becomes the open passage before the pressure in the compressor reaches the failure
pressure.
5 [Claim 4]
The air-conditioning apparatus of claim 3, wherein an inside diameter of the
cylindrical portion is one-tenth or more of an inside diameter of a drum of a casing of
the compressor, and a thickness of the closing portion is one-tenth or more of a
thickness of the casing of the compressor.
10 [Claim 5]
The air-conditioning apparatus of claim 4, wherein a thickness of the cylindrical
portion is larger than the thickness of the closing portion.
[Claim 6]
The air-conditioning apparatus of claim 4 or 5, wherein the opening valve is
15 disposed at the casing of the compressor.
[Claim 7]
The air-conditioning apparatus of any one of claims 1 to 5, wherein the opening
valve is disposed at one of the refrigerant pipes that is connected to a discharge port
of the compressor.
20 [Claim 8]
The air-conditioning apparatus of claim 7, wherein the opening valve is
disposed at one of the refrigerant pipes that connects the compressor and one of
components closest to the compressor, and the components are included in the
refrigerant circuit and are positioned downstream of the compressor in the refrigerant
25
23
circuit in a cooling operation of the air-conditioning apparatus.