Air-conditioning device

Abstract

An air-conditioning device includes: an outdoor unit; a plurality of indoor units; a plurality of liquid refrigerant flow passages and a plurality of gas refrigerant flow passages; and a shutoff valve device provided between the outdoor unit and the plurality of indoor units and is capable of controlling a flow of a refrigerant in the liquid refrigerant flow passages and the gas refrigerant flow passages. The shutoff valve device includes: a liquid-side control valve that is provided in common to the plurality of liquid refrigerant flow passages and is capable of shutting off the flow of the refrigerant through the plurality of liquid refrigerant flow passages; a gas-side control valve that is provided in each of the plurality of gas refrigerant flow passages and is capable of shutting off the flow of the refrigerant through the plurality of gas refrigerant flow passages; a bypass path that connects one of the liquid refrigerant flow passages closer to the indoor unit relative to the liquid-side control valve and one of the gas refrigerant flow passages closer to the indoor unit relative to the gas-side control valve; and a pressure relief valve that is provided on the bypass path and is normally in a closed state, and that when pressure reaches a preset pressure or higher, comes into an open state by operating using the pressure without using electric power to release pressure of the refrigerant from the liquid refrigerant flow passage to the gas refrigerant flow passage.

Description

Technical Field

[0001] An embodiment of the present invention relates to an air-conditioning device.Background Art

[0002] As a refrigerant for air-conditioning devices, refrigerants with low global warming potential (GWP), what is called low-GWP refrigerants, are being increasingly used these days. In general, however, low-GWP refrigerants are flammable refrigerants including mildly flammable refrigerants in many cases. Thus, in the case of using a flammable refrigerant, safety needs to be ensured when it leaks out from an apparatus.

[0003] Therefore, safety measures required to be taken according to the amount of refrigerant sealed in an air-conditioning device as a whole and the volume of a room in which an indoor unit is installed have been prescribed in Europe, for example. An example of such a safety measure is a method in which a shutoff device is provided between the indoor unit and the outdoor unit to shut off a flow of a refrigerant, and when leakage of the refrigerant is detected, the shutoff device can be operated to cut off supply of the refrigerant to the indoor unit.Citation ListPatent Literature

[0004] Patent Literature 1: International Publication No. WO 2018 / 062528Summary of InventionTechnical Problem

[0005] However, there is still room for improvement in terms of safety and reliability in the configuration according to the related art.

[0006] Therefore, an air-conditioning device capable of improving safety and reliability against leakage of a refrigerant is provided.Solution to Problem

[0007] An air-conditioning device of an embodiment includes: an outdoor unit including an outdoor heat exchanger and a compressor; a plurality of indoor units each including an indoor heat exchanger connected to the outdoor heat exchanger and the compressor; a plurality of liquid refrigerant flow passages through which a liquid refrigerant flows and a plurality of gas refrigerant flow passages through which a gaseous refrigerant flows, the plurality of liquid refrigerant flow passages and the plurality of gas refrigerant flow passages connecting the outdoor unit and the plurality of indoor units; a shutoff valve device that is provided between the outdoor unit and the plurality of indoor units and is capable of controlling a flow of a refrigerant in the liquid refrigerant flow passages and the gas refrigerant flow passages. The shutoff valve device includes: a liquid-side control valve that is provided in common to the plurality of liquid refrigerant flow passages and is capable of shutting off the flow of the refrigerant through the plurality of liquid refrigerant flow passages; a gas-side control valve that is provided in each of the plurality of gas refrigerant flow passages and is capable of shutting off the flow of the refrigerant through the plurality of gas refrigerant flow passages; a bypass path that connects one of the liquid refrigerant flow passages closer to the indoor unit relative to the liquid-side control valve and one of the gas refrigerant flow passages closer to the indoor unit relative to the gas-side control valve; and a pressure relief valve that is provided on the bypass path and is normally in a closed state, and that when pressure reaches a preset pressure or higher, comes into an open state by operating using the pressure without using electric power to release pressure of the refrigerant from the liquid refrigerant flow passage to the gas refrigerant flow passage.Brief Description of Drawings

[0008] [Figure 1] Figure 1 is a refrigeration cycle diagram showing an example of an air-conditioning device according to an embodiment. [Figure 2] Figure 2 is a refrigeration cycle diagram showing a flow of a refrigerant when a full heating operation is executed in the air-conditioning device according to the embodiment. [Figure 3] Figure 3 is a refrigeration cycle diagram showing a flow of the refrigerant when a full cooling operation is executed in the air-conditioning device according to the embodiment. [Figure 4] Figure 4 is a refrigeration cycle diagram showing an example of a flow of the refrigerant when a simultaneous heating and cooling operation is executed in the air-conditioning device according to the embodiment. [Figure 5] Figure 5 is a block diagram showing an example of an electric configuration of the air-conditioning device according to the embodiment. [Figure 6] Figure 6 is a diagram showing an example of an installation mode of a bypass path and a pressure relief valve in the air-conditioning device according to the embodiment. [Figure 7] Figure 7 is a refrigeration cycle diagram showing an example of a flow of the refrigerant when recovery processing is executed in the multi-type air-conditioning device. Description of Embodiment

[0009] Hereinafter, an embodiment will be described with reference to the drawings.

[0010] An air-conditioning device 1 shown in Figure 1 is a so-called multi-type air-conditioning device including a plurality of indoor units for one outdoor unit and capable of performing a full heating operation, a full cooling operation, and a simultaneous cooling and heating operation. The full heating operation is an operation mode in which all indoor units perform a heating operation. The full cooling operation is an operation mode in which all indoor units perform a cooling operation. The simultaneous heating and cooling operation is an operation mode in which indoor units performing a cooling operation and indoor units performing a heating operation are present in a mixed manner. In the following description, the full heating operation, the full cooling operation, and the simultaneous heating and cooling operation will be collectively referred to as an air-conditioning operation in some cases. In addition, the multi-type air-conditioning device refers to a configuration in which a plurality of indoor units are operated by one outdoor unit.

[0011] The air-conditioning device 1 is configured to be capable of operating a plurality of indoor units 201, 202, and 203 with one outdoor unit 10. The air-conditioning device 1 includes, for example, the one outdoor unit 10, the plurality of indoor units 201 to 203, and a shutoff valve device 30. The outdoor unit 10, each of the indoor units 201 to 203, and the shutoff valve device 30 configure one refrigeration cycle capable of circulating a refrigerant.

[0012] In the present embodiment, the shutoff valve device 30 is configured as a multi-port shutoff valve device. The multi-port shutoff valve device means a shutoff valve device including a plurality of pairs of ports for connecting indoor units, that is, pairs of refrigerant pipes serving as inlets and outlets. A shutoff valve device including only one pair of ports for connecting indoor units is called a single-port shutoff valve device. The shutoff valve device 30 of the present embodiment includes three pairs of refrigerant pipes, which connect, for example, the three indoor units 201 to 203, that is, a pair of refrigerant pipes 461 and 43, a pair of refrigerant pipes 462 and 44, and a pair of refrigerant pipes 463 and 45.

[0013] The outdoor unit 10 is installed outdoors. The outdoor unit 10 includes an outdoor heat exchanger 11, an outdoor fan 12, an outdoor expansion valve 13, a compressor 14, a first switching valve 15, and a second switching valve 16 as shown in the refrigeration cycle diagram of Figure 1. The outdoor heat exchanger 11 has a function of exchanging heat between the refrigerant passing through the outdoor heat exchanger 11 and outside air. The outdoor fan 12 has a function of blowing air to the outdoor heat exchanger 11 to promote heat exchange in the outdoor heat exchanger 11. A mildly flammable or a flammable refrigerant is used as a refrigerant in the refrigeration cycle. In the present embodiment, mildly flammable R32, for example, is used as a refrigerant.

[0014] The outdoor expansion valve 13 is provided in a liquid-side refrigerant pipe 46 directed from the outdoor unit 10 toward the indoor units 201 to 203. The outdoor expansion valve 13 has a function of adjusting the area of a flow passage of the refrigerant passing through the inside of the outdoor expansion valve 13 to depressurize the refrigerant, thereby adjusting a flow rate and pressure of the refrigerant flowing out of the outdoor heat exchanger 11 or the refrigerant flowing into the outdoor heat exchanger 11. The outdoor expansion valve 13 can be configured by an electronic expansion valve that is driven by receiving an electric signal from a computer called MCU provided in an outdoor control unit 17 of the outdoor unit 10 as shown in Figure 5, for example. The MCU is an abbreviation for micro control unit.

[0015] The first switching valve 15 and the second switching valve 16 have a function of switching a flow direction of the refrigerant in the refrigeration cycle, that is, a direction in which the refrigerant discharged from the compressor 14 flows. The first switching valve 15 and the second switching valve 16 are configured by a four-way valve that is driven by receiving an electric signal, for example, but a plurality of valves other than the four-way valve may be combined as long as the same flow of the refrigerant can be formed.

[0016] The compressor 14 compresses the refrigerant flowing in the refrigeration cycle and discharges the refrigerant in a direction indicated by an open arrow in Figure 1, for example. Depending on a switching state of the first switching valve 15 and the second switching valve 16, the compressor 14 sucks the refrigerant on the outdoor heat exchanger 11 and discharges the sucked refrigerant toward the shutoff valve device 30 side as shown in Figure 2, or sucks the refrigerant on the shutoff valve device 30 and discharges the sucked refrigerant toward the outdoor heat exchanger 11 as shown in Figure 3.

[0017] Each of the indoor units 201 to 203 is installed in a room that is subjected to the air-conditioning operation. Each of the indoor units 201 to 203 includes an indoor heat exchanger 21, an indoor fan 22, an indoor expansion valve 23, and a leakage sensor 24. Although each of the indoor units 201 to 203 can basically have the same configuration, performance and the like of the indoor heat exchanger 21, the indoor expansion valve 23, the indoor fan 22, and the leakage sensor 24 can be changed as appropriate depending on the volume of an installation space.

[0018] The indoor heat exchanger 21 exchanges heat between the refrigerant passing through the inside of the indoor heat exchanger 21 and air in the room in which each of the indoor units 201 to 203 is installed. The indoor heat exchanger 21 is connected to the outdoor heat exchanger 11 and the compressor 14, and is configured to allow the refrigerant to circulate among the outdoor heat exchanger 11, the indoor heat exchanger 21, and the compressor 14. The indoor fan 22 has a function of blowing air to the indoor heat exchanger 21 to promote heat exchange in the indoor heat exchanger 21 and supplying air adjusted in temperature by the indoor heat exchanger 21 into the room.

[0019] The indoor expansion valve 23 has a function of adjusting the flow passage area of the refrigerant passing through the indoor expansion valve 23 to control the amount of refrigerant flow. The indoor expansion valve 23 can be configured by, for example, an electronic expansion valve that is driven by receiving an electric signal from a computer such as MCU provided in an indoor control unit 25 of each of the indoor units 201 to 203, similarly to the outdoor expansion valve 13.

[0020] As shown in Figure 5, each of the indoor units 201 to 203 includes the indoor control unit 25. The shutoff valve device 30 also includes a control unit configured with a computer, which is not shown in detail in the drawing. The outdoor control unit 17 of the outdoor unit 10 and the indoor control unit 25 of each of the indoor units 201 to 203, and the control unit (not shown) of the shutoff valve device 30 are mutually connected with communication lines, and exchange various types of information.

[0021] The leakage sensor 24 has a function of detecting leakage of the refrigerant in each of the indoor units 201 to 203. The leakage sensor 24 may be incorporated in each of the indoor units 201 to 203 or may be installed independently as a leakage sensor unit in an indoor space of each room in which each of the indoor units 201 to 203 is installed. In the case of the present embodiment, each of the indoor units 201 to 203 is provided with the leakage sensor 24. The leakage sensor 24 can be configured by a semiconductor gas sensor, for example. The leakage sensor 24 has performance capable of detecting the refrigerant, for example, R32 sealed in the refrigeration cycle. The leakage sensor 24 outputs an electric signal, which changes linearly according to the concentration of the refrigerant, for example, for the refrigerant of approximately 300 to 30,000 ppm in the air, and when the detected concentration exceeds a predetermined value, notifies the corresponding indoor units 201 to 203 and the outdoor unit 10 that refrigerant leakage occurs.

[0022] The shutoff valve device 30 is provided between the outdoor unit 10 and the respective indoor units 201 to 203. In other words, the outdoor unit 10 and the respective indoor units 201 to 203 are connected via the shutoff valve device 30. The shutoff valve device 30 includes a plurality of gas control valve units 31, 32, and 33 (in this case, three) corresponding to the plurality of indoor units 201 to 203 connected to the shutoff valve device 30 and one liquid-side control valve 34. In a case of distinguishing from each other in the following description, the gas control valve units 31, 32, and 33 may be referred to as a first gas control valve unit 31, a second gas control valve unit 32, and a third gas control valve unit 33, respectively.

[0023] The gas control valve units 31 to 33 include the gas-side control valves 311 and 312, the gas-side control valves 321 and 322, and the gas-side control valves 331 and 332, respectively. Each of the gas control valve units 31 to 33 may include one gas-side control valve. The gas-side control valves 311, 312, 321, 322, 331, and 332 are provided on paths of gas-side refrigerant pipes 431, 432, 441, 442, 451, and 452, respectively, and have a function of controlling the flow of the gaseous refrigerant.

[0024] The gas-side refrigerant pipes 431, 432, 441, 442, 451, and 452 are part of refrigerant flow passages that connect the indoor heat exchangers 21 of each of the indoor units 201 to 203 and the compressor 14, and allow the gaseous refrigerant to pass. The gas-side refrigerant pipes 431, 432, 441, 442, 451, and 452 join to become the gas-side refrigerant pipes 43, 44, and 45, respectively, which are connected to the indoor heat exchangers 21 of the indoor units 201 to 203, respectively. In this case, the liquid-side refrigerant pipes 461 to 463 and the gas-side refrigerant pipes 43 to 45 connected to the indoor units 201 to 203, respectively, form refrigerant flow passages to which the indoor units 201 to 203 are connected, respectively.

[0025] In a case of distinguishing from each other in the following description, the liquid-side refrigerant pipes 461 to 463 and the gas-side refrigerant pipes 43 to 45 will be referred to as, from the side closest to the liquid-side control valve 34, the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43, the second liquid-side refrigerant pipe 462 and the second gas-side refrigerant pipe 44, and the third liquid-side refrigerant pipe 463 and the third gas-side refrigerant pipe 45. Furthermore, in a case of distinguishing from each other, the indoor units 201, 202, and 203 may be referred to as the first indoor unit 201 connected to the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43, the second indoor unit 202 connected to the second liquid-side refrigerant pipe 462 and the second gas-side refrigerant pipe 44, and the third indoor unit 203 connected to the third liquid-side refrigerant pipe 463 and the third gas-side refrigerant pipe 45, respectively.

[0026] The gas-side control valves 311, 312, 321, 322, 331, and 332 can each be configured by, for example, an electronic control valve capable of what is called electronic control, which is to be driven upon receipt of an electric signal. The gas-side control valves 311, 312, 321, 322, 331, and 332 can adjust their openings, that is, the flow rate of the refrigerant flowing in a corresponding one of the gas-side refrigerant pipes 431, 432, 441, 442, 451, and 452, based on electrical control from the control unit of the shutoff valve device 30.

[0027] In each of the gas control valve units 31, 32, and 33, one of the pair of gas-side control valves 311 and 312, 321 and 322, and 331 and 332 is adaptable for high-pressure gas and the other is adapted for low-pressure gas. In the present embodiment, for example, the gas-side control valves 311, 321, and 331 are adapted for high-pressure gas, and the gas-side control valves 312, 322, and 332 are adapted for low-pressure gas. The air-conditioning device 1 can shut off the refrigerant flowing between the indoor heat exchanger 21 of each of the indoor units 201 to 203 and the compressor 14, that is, the refrigerant flowing in the gas-side refrigerant pipes 431, 432, 441, 442, 451, and 452 by closing the gas-side control valves 311, 312, 321, 322, 331, and 332 of each of the gas control valve units 31, 32, and 33.

[0028] The liquid-side control valve 34 is provided on the way of the liquid-side refrigerant pipe 46 that connects the outdoor heat exchanger 11 and the indoor heat exchanger 21 of each of the indoor units 201 to 203, and has a function of controlling the flow of the liquid refrigerant. The liquid-side refrigerant pipe 46 is a refrigerant flow passage that connects the outdoor heat exchanger 11 and the indoor heat exchanger 21 of each of the indoor units 201 to 203 and allows the liquid refrigerant to flow. The liquid-side refrigerant pipe 46 branches into the liquid-side refrigerant pipes 461 to 463 on sides closer to the respective indoor units 201 to 203 relative to the liquid-side control valve 34, and each of these pipes is connected to one end of the indoor heat exchanger 21 of each of the indoor units 201 to 203.

[0029] In the present embodiment, the shutoff valve device 30 will be described using an example in which the three indoor units 201 to 203 can be connected, but there are also models, that is, types in which two and four or more indoor units are connected. In any model, only one liquid-side control valve 34 is provided in the liquid-side refrigerant pipe 46. This configuration simplifies the arrangement of the refrigerant circuit and piping. Note that the number of the gas-side control valves 311, 312, 321, 322, 331, and 332 is required to be twice the number of the indoor units 201 to 203 to be connected.

[0030] The liquid-side control valve 34 can be configured by, for example, an electronic control valve capable of what is called electronic control, which is to be driven upon receipt of an electric signal. The liquid-side control valve 34 can adjust its opening, that is, the flow rate of the refrigerant flowing through the liquid-side refrigerant pipes 46 and 461 to 463, based on electrical control from the control unit of the shutoff valve device 30, and has a function of completely shutting off the flow of the refrigerant in the liquid-side refrigerant pipes 46 and 461 to 463.

[0031] As shown in Figure 5, the air-conditioning device 1 further includes a backup power supply 37 such as a storage battery. The backup power supply 37 can be configured as, for example, an element of the shutoff valve device 30, or can be configured as an element separate from the shutoff valve device 30. The backup power supply 37 has a function of supplying power to the gas-side control valves 311, 312, 321, 322, 331, and 332 and the liquid-side control valve 34 to close these valves when a power outage occurs.

[0032] The shutoff valve device 30 further includes a bypass path 35 and a pressure relief valve 36. The bypass path 35 and the pressure relief valve 36 are connected to one of the plurality of gas control valve units 31 to 33. The bypass path 35 is provided at a connection position between the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43, which are closest to the liquid-side control valve 34, among the liquid-side refrigerant pipes 461, 462, and 463 which are a plurality of liquid-side refrigerant flow passages and the gas-side refrigerant pipes 43, 44, and 45 which are a plurality of gas-side refrigerant flow passage.

[0033] In other words, the bypass path 35 and the pressure relief valve 36 are provided in the first gas control valve unit 31 in the case of the present embodiment. The bypass path 35 connects the liquid-side refrigerant pipe 461, which is the liquid-side refrigerant flow passage, and the gas-side refrigerant pipe 43, which is the gas-side refrigerant flow passage, with the indoor unit 201 interposed therebetween. Specifically, the bypass path 35 connects a side of the liquid-side refrigerant pipe 461 closer to the indoor unit 201 relative to the liquid-side control valve 34 and a side of the gas-side refrigerant pipe 43 closer to the indoor unit 201 relative to the gas-side control valves 311 and 312.

[0034] The pressure relief valve 36 is provided on the bypass path 35. The pressure relief valve 36 may be configured as, for example, a mechanical valve that operates by pressure without electric power. The pressure relief valve 36 can be configured as a check valve that, when a pressure difference between the liquid-side refrigerant pipe 461 and the gas-side refrigerant pipe 43 becomes equal to or greater than a predetermined value, allows the refrigerant to flow from the liquid-side refrigerant pipe 461 toward the gas-side refrigerant pipe 43 and allows the refrigerant not to flow from the gas-side refrigerant pipe 43 toward the liquid-side refrigerant pipe 461. The pressure relief valve 36 is set to be closed normally.

[0035] When the pressure difference between the gas-side refrigerant pipe 43 and the liquid-side refrigerant pipe 461 becomes equal to or greater than the preset predetermined pressure, that is, when the pressure of the liquid-side refrigerant pipe 461 relative to the gas-side refrigerant pipe 43 becomes equal to or greater than the preset predetermined pressure, the pressure relief valve 36 operates by the pressure without using electric power and is in an open state. Thus, the pressure relief valve 36 releases a part of the refrigerant pressure from the liquid-side refrigerant pipe 461 to the gas-side refrigerant pipe 43. An operating pressure, that is, the pressure for causing an open state of the pressure relief valve 36, is set to, for example, about 4 MPa. In this case, the operating pressure of the pressure relief valve 36 is set to a value lower than a withstand pressure of the indoor expansion valve 23. Thus, even when the liquid-side refrigerant pipe 461 is in a liquid sealed state and the pressure rises, the pressure relief valve 36 opens before the indoor expansion valve 23 is broken, and the pressure in the liquid-side refrigerant pipe 461 can be reduced.

[0036] As shown in Figure 6, the pressure relief valve 36 is configured, for example, in an elongated shape that is long in one direction as a whole. In this case, the pressure relief valve 36 is installed in an orientation in which a longitudinal direction of the pressure relief valve 36 is a horizontal direction. For this reason, the shutoff valve device 30 is reduced in a dimension in a height direction, compared to a case in which the pressure relief valve 36 is installed in an orientation in which the longitudinal direction of the pressure relief valve 36 is a vertical direction. Therefore, the shutoff valve device 30 can be easily installed in a space with a small dimension in the height direction, for example, the inside of a ceil.

[0037] Moreover, the bypass path 35 does not connect the liquid-side refrigerant pipe 461 and the gas-side refrigerant pipe 43 in a straight line, that is, over the shortest distance, but is configured to pass vertically above the liquid-side refrigerant pipe 461 and the gas-side refrigerant pipe 43. The pressure relief valve 36 is arranged on the bypass path 35 above a connection portion 351 between the bypass path 35 and the liquid-side refrigerant pipe 461 and a connection portion 352 between the bypass path 35 and the gas-side refrigerant pipe 43 in the vertical direction.

[0038] Next, the flow of the refrigerant during the operation of the air-conditioning device 1 will be described with reference to Figures 2 to 4 and 7. In Figures 2 to 4 and 7, black thick lines and open arrows in the refrigerant flow passages are intended illustrate a main flow of the refrigerant in each operation and may be different from an actual flow of the refrigerant. In other words, portions not indicated by the black thick lines may be actually filled with the refrigerant.

[0039] In the case of executing the full heating operation, the air-conditioning device 1 switches the first switching valve 15 to a mode of connecting a sucking side of the compressor 14 and the outdoor heat exchanger 11 and switches the second switching valve 16 to a mode of connecting a discharging side of the compressor 14 and the indoor heat exchanger 21 of each of the indoor units 201 to 203, as shown in Figure 2. In the full heating operation, the outdoor heat exchanger 11 functions as an evaporator, and the indoor heat exchangers 21 of all of the indoor units 201 to 203 function as condensers.

[0040] In this case, the air-conditioning device 1 closes the gas-side control valves 312, 322, and 332 adapted for the low-pressure gas and opens the gas-side control valves 311, 321, and 331 adapted for the high-pressure gas. Then, each of the indoor units 201 to 203 controls the opening degree of the indoor expansion valve 23 of its own, thereby adjusting output of heating in each of the indoor units 201 to 202.

[0041] In the case of executing the full cooling operation, the air-conditioning device 1 switches the first switching valve 15 to a mode of connecting the discharging side of the compressor 14 and the outdoor heat exchanger 11 and switches the second switching valve 16 to a mode of connecting the sucking side of the compressor 14 and the indoor heat exchanger 21 of each of the indoor units 201 to 203, as shown in Figure 3. In the full cooling operation, the outdoor heat exchanger 11 functions as a condenser, and the indoor heat exchangers 21 of all of the indoor units 201 to 203 function as evaporators.

[0042] In this case, looking at the shutoff valve device 30, the air-conditioning device 1 opens the gas-side control valves 312, 322, and 332 adapted for the low-pressure gas and closes the gas-side control valves 311, 321, and 331 adapted for the high-pressure gas. Then, each of the indoor units 201 to 203 controls the opening degree of the indoor expansion valve 23 of its own, thereby adjusting output of cooling in each of the indoor units 201 to 203.

[0043] In the case of executing the simultaneous heating and cooling operation, the air-conditioning device 1 performs operation based on the full heating operation shown in Figure 2 or the full cooling operation shown in Figure 3. Then, the air-conditioning device 1 closes the gas-side control valves 311, 321, and 331 adapted for the high-pressure gas and opens the gas-side control valves 312, 322, and 332 adapted for the low-pressure gas, among the plurality of gas-side control valves 311, 312, 321, 322, 331, and 332 connected to the indoor units 201 to 203 that perform different operations, thereby making the refrigerant flow direction for the indoor units 201 to 203 that perform different operations opposite to that of the other indoor units 201 to 203. This can allow the air-conditioning device 1 to perform an operation opposite to the basic operation for some of the indoor units 201 to 203.

[0044] An example shown in Figure 4, for example, is a mode which is based on the full heating operation and in which only the third indoor unit 203 among the respective indoor units 201 to 203 performs the cooling operation. In this case, the air-conditioning device 1 closes the gas-side control valve 331 adapted for the high-pressure and low-pressure gas and opens the gas-side control valve 332 adapted for the low-pressure gas, between the gas-side control valves 331 and 332 connected to the indoor heat exchanger 21 of the third indoor unit 203. Then, the refrigerant having been heat dissipated in the indoor heat exchangers 21 of the indoor units 201 and 202 other than the third indoor unit 203 flows into the indoor heat exchanger 21 of the third indoor unit 203, so that only the indoor heat exchanger 21 of the third indoor unit 203 functions as an evaporator. Accordingly, the first indoor unit 201 and the second indoor unit 202 perform heating operation, and the third indoor unit 203 performs cooling operation.

[0045] In the cooling and heating mixed operation, whether to use the full heating operation or the full cooling operation as the basis can be determined according to a proportion occupied by the heating operation or the cooling operation to the whole. When performing the cooling and heating mixed operation, the air-conditioning device 1 can set the basic operation to the full heating operation, for example, if the proportion of the heating operation to the whole is large, and set the basic operation to the full cooling operation if the proportion of the cooling operation to the whole is large.

[0046] Next, an electric configuration of the air-conditioning device 1 will be described with reference to Figure 5. The outdoor unit 10 further includes the outdoor control unit 17. The respective indoor units 201 to 203 each further includes an indoor control unit 25. The outdoor control unit 17 and the indoor control unit 25 can include a computer or the like having an arithmetic unit such as a CPU, a transitory storage medium such as a RAM, a non-transitory storage medium such as a ROM or a main memory that stores a control program of an apparatus, and the like, for example.

[0047] The outdoor control unit 17 controls an overall behavior of the air-conditioning device 1. The outdoor fan 12, the outdoor expansion valve 13, the compressor 14, the first switching valve 15, and the second switching valve 16 are electrically connected to the outdoor control unit 17. The outdoor control unit 17 controls behaviors of the outdoor fan 12, the outdoor expansion valve 13, the compressor 14, the first switching valve 15, and the second switching valve 16.

[0048] The indoor control unit 25 of each of the indoor units 201 to 203 is electrically connected to the outdoor control unit 17 to be communicable with each other via a wired line or a wireless communication device (not shown). In the example of Figure 5, the outdoor control unit 17 is connected to the indoor control unit 25 of the indoor unit 201 by a signal line 61, and the indoor control units 25 of the indoor units 201 to 203 are connected to each other by signal lines 62, respectively. In other words, the outdoor control unit 17 is connected to each of the indoor control units 25 of the indoor units 201 to 203 in a daisy chain manner, for example. Thus, the indoor control unit 25 of each of the indoor units 201 to 203 is electrically connected to the outdoor control unit 17 to be communicable to each other. Furthermore, signal lines 251 to 253 extending from the indoor control units 25 of the indoor units 201 to 203 are respectively connected to ports 51 to 53 of the terminal block 50 of the shutoff valve device 30. In this case, the ports 51 to 53 of the terminal block 50 correspond to the port pairs of the shutoff valve device 30 in Figure 1, that is, the liquid-side refrigerant pipes 461 to 463 and the gas-side refrigerant pipes 43 to 45, respectively.

[0049] In the following description, the port 51 corresponding to the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43 may be referred to as a first port 51, the port 52 corresponding to the second liquid-side refrigerant pipe 462 and the second gas-side refrigerant pipe 44 may be referred to as a second port 52, and the port 53 corresponding to the third liquid-side refrigerant pipe 463 and the third gas-side refrigerant pipe 45 may be referred to as a third port 53. The outdoor control unit 17 can detect through, for example, each of the indoor control units 25 whether the indoor control units 25 are connected to the ports 51 to 53, respectively. Then, the outdoor control unit 17 can detect whether the indoor units 201 to 203 are connected to the liquid-side refrigerant pipes 461 to 463 and the gas-side refrigerant pipes 43 to 45, respectively, based on whether the indoor control units 25 are connected to the ports 51 to 53, respectively.

[0050] The indoor fan 22, the indoor expansion valve 23, and the leakage sensor 24 of each of the indoor units 201 to 203 are electrically connected to the indoor control unit 25 of each of the indoor units 201 to 203. The indoor control unit 25 of each of the indoor units 201 to 203 controls behaviors of the indoor fan 22, the indoor expansion valve 23, and the leakage sensor 24 of each of the indoor units 201 to 203 based on commands from the outdoor control unit 17. A result of detection from the leakage sensor 24 provided for each of the indoor units 201 to 203 is transmitted to the outdoor control unit 17 via the indoor control unit 25 of each of the indoor units 201 to 203.

[0051] The shutoff valve device 30 is electrically connected to the indoor control unit 25 of each of the indoor units 201 to 203 to be controlled by the shutoff valve device 30. Then, the indoor control unit 25 of each of the indoor units 201 to 203 controls a behavior of the shutoff valve device 30 based on a command from the outdoor control unit 17. As described above, the present embodiment is configured in which the outdoor control unit 17 plays a central role of instructing all of the indoor units 201 to 203 and the shutoff valve device 30 to control the behavior of each equipment.

[0052] The air-conditioning device 1 further includes a detection processing unit 171, a report processing unit 172, and a recovery processing unit 173 as shown in Figure 5. The detection processing unit 171, the report processing unit 172, and the recovery processing unit 173 may be realized when a CPU possessed by the outdoor control unit 17 executes a predetermined program, for example. In addition, the detection processing unit 171, the report processing unit 172, and the recovery processing unit 173 may be realized only by hardware such as an integrated circuit in which a predetermined program is implemented, or some functions may be realized by dedicated hardware, and others may be realized by a combination of hardware and a program. Furthermore, the detection processing unit 171, the report processing unit 172, and the recovery processing unit 173 may be realized as functions of the indoor control unit 25 rather than the outdoor control unit 17, or may be realized as functions separately possessed by the outdoor control unit 17 and the indoor control unit 25.

[0053] The detection processing unit 171 can execute detection processing. The detection processing is processing that is executed, for example, during assembly, such as during pipework in the air-conditioning device 1, but may also be executed during a normal operation of the air-conditioning device 1. The detection processing includes processing of detecting an unconnected state in which the indoor unit 201 is not connected to the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43 in which the bypass path 35 is provided. For example, the detection processing unit 171 outputs a signal from the outdoor control unit 17 to the first port 51, and determines that the indoor control unit 25 is connected to the first port 51 when there is a response to the signal from the indoor control unit 25. In this case, the detection processing unit 171 detects a connected state in which the indoor unit 201 is connected to the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43. In contrast, when there is no response from the indoor control unit 25 to the signal output from the outdoor control unit 17 to the first port 51, the detection processing unit 171 detects an unconnected state in which the indoor control unit 25 is not connected to the first port 51.

[0054] The report processing unit 172 can execute report processing. The report processing is processing that is executed, for example, during pipework in the air-conditioning device 1, similarly to the detection processing, but may also be executed during a normal operation of the air-conditioning device 1. When the detection processing unit 171 detects the unconnected state in which the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43 provided with the bypass path 35 are in the unconnected state, the report processing uses a report unit 18 or the like to notify a worker or the like of the unconnected state. The report unit 18 is, for example, a speaker or a display provided in the outdoor unit 10 or each of the indoor units 201 to 203, and may additionally be an external device connected via a telecommunication line, such as a server or a mobile terminal of a maintenance company.

[0055] The recovery processing unit 173 can execute recovery processing. The recovery processing includes processing of causing the compressor 14 to operate in a state where the liquid-side control valve 34 is closed to recover the refrigerant remaining in each of the indoor heat exchangers 21 toward the compressor 14 as shown in Figure 7. The recovery processing unit 173 executes the recovery processing in a case where at least one of the leakage sensors 24 provided in the plurality of indoor units 201 to 203 connected to the shutoff valve device 30 detects leakage of the refrigerant.

[0056] When executing the recovery processing, the recovery processing unit 173 first closes the liquid-side control valve 34 to cut off supply of the refrigerant to the indoor heat exchangers 21 of all of the indoor units 201 to 203 provided in the air-conditioning device 1. Moreover, the recovery processing unit 173 operates the compressor 14 by fully opening all valves 23, 311, 312, 321, 322, 331, and 332 other than the liquid-side control valve 34 out of the control valves provided in the shutoff valve device 30 and the indoor units 201 to 203, or by opening theses valves to a large degree that allows the refrigerant to flow smoothly. At this time, the recovery processing unit 173 maintains the first switching valve 15 in a mode of connecting the discharge side of the compressor 14 to the outdoor heat exchanger 11, and maintains the second switching valve 16 in a mode of connecting the suction side of the compressor 14 to the indoor heat exchanger 21 of each of the indoor units 201 to 203.

[0057] In other words, the recovery processing unit 173 maintains the first switching valve 15 and the second switching valve 16 in the same mode as in the full cooling operation shown in Figure 3. Thus, the refrigerant remaining in the indoor heat exchanger 21 of each of the indoor units 201, 202, and 203 is recovered toward the compressor 14. Therefore, the refrigerant is removed from the indoor heat exchangers 21 of all of the indoor units 201 to 203, and thus additional leakage of the refrigerant is prevented. Then, the recovery processing unit 173 operates the compressor 14 to recover the refrigerant for a certain period, fully closes the respective gas-side control valves 311, 312, 321, 322, 331, and 332 being open, and then stops the compressor 14 to complete the recovery processing. It should be noted that there is no particular need to close the indoor expansion valve 23 of each of the indoor units 201 to 203 from the fact that the flow of the refrigerant has already been blocked by the liquid-side control valve 34 located upstream thereof.

[0058] As described above, the air-conditioning device 1 includes the outdoor unit 10, the plurality of indoor units 201 to 203, the plurality of liquid-side refrigerant pipes 46 and 461 to 463, the plurality of gas-side refrigerant pipes 43 to 45, 431, 432, 441, 442, 451, and 452, and the shutoff valve device 30. The outdoor unit 10 includes the outdoor heat exchanger 11 and the compressor 14. Each of the indoor units 201 to 203 includes the indoor heat exchanger 21 connected to the outdoor heat exchanger 11 and the compressor 14.

[0059] The liquid-side refrigerant pipes 46 and 461 to 463 connect the outdoor unit 10 and the respective indoor units 201 to 203, and function as a plurality of liquid refrigerant flow passages through which the liquid refrigerant flows. The gas-side refrigerant pipes 43 to 45, 431, 432, 441, 442, 451, and 452 connect the outdoor unit 10 and the respective indoor units 201 to 203, and function as a plurality of gas refrigerant flow passages through which the gaseous refrigerant flows. The shutoff valve device 30 is provided between the outdoor unit 10 and the plurality of indoor units 201 to 203, and has a function of controlling the flow of refrigerant in the liquid-side refrigerant pipes 46 and 461 to 463 and the gas-side refrigerant pipes 43 to 45, 431, 432, 441, 442, 451, and 452.

[0060] The shutoff valve device 30 includes the liquid-side control valve 34 and the gas-side control valves 311, 312, 321, 322, 331, and 332. The liquid-side control valve 34 is provided in common in each of the liquid-side refrigerant pipes 461 to 463, and is configured to be able to shut off the flow of the refrigerant to each of the liquid-side refrigerant pipes 461 to 463. The gas-side control valves 311, 312, 321, 322, 331, and 332 are provided in the gas-side refrigerant pipes 43 to 45, respectively, and are configured to able to shut off the flow of the refrigerant to the gas-side refrigerant pipes 43 to 45, respectively.

[0061] Accordingly, as described above, when the refrigerant leaks in each of the indoor units 201 to 203, the air-conditioning device 1 closes the liquid-side control valve 34 of the shutoff valve device 30 to cut off the supply of the refrigerant to each of the indoor units 201 to 203 and performs the recovery processing, whereby it is possible to prevent the refrigerant leakage from increasing.

[0062] On the other hand, when a power outage occurs while some or all of the indoor units 201 to 203 are stopped, the indoor expansion valve 23 is in a closed state. When power is supplied from a backup power supply 37 and the liquid-side control valve 34 and the gas-side control valves 311, 312, 321, 322, 331, and 332 of the shutoff valve device 30 are closed, the refrigerant is sealed in the liquid-side refrigerant pipes 461 to 463 for connecting the indoor expansion valve 23 and the liquid-side control valve 34 being in the closed state and is brought into a liquid sealed state. Then, the pressure inside the liquid-side refrigerant pipes 461 to 463 being in the liquid sealed state becomes more likely to rise, resulting in increasing the risk of damage to the liquid-side refrigerant pipes 461 to 463 and the leakage of the refrigerant.

[0063] Therefore, the shutoff valve device 30 further includes the bypass path 35 and the pressure relief valve 36. The bypass path 35 connects the liquid-side refrigerant pipes 46 and 461 to 463 and the gas-side refrigerant pipes 43 to 45, 431, 432, 441, 442, 451, and 452 with the indoor units 201 to 203 interposed therebetween. In the example of Figure 1, the bypass path 35 connects the liquid-side refrigerant pipe 461 and the gas-side refrigerant pipe 43 with the first indoor unit 201 interposed therebetween.

[0064] The pressure relief valve 36 is provided on the bypass path 35. The pressure relief valve 36 is normally in a closed state, and when pressure reaches a preset pressure or higher, comes into an open state by operating without using electric power due to the pressure to release the pressure of the refrigerant from the liquid-side refrigerant pipe 461 to the gas-side refrigerant pipe 43.

[0065] Thus, for example, even if the liquid-side control valve 34 and the gas-side control valves 311, 312, 321, 322, 331, and 332 of the shutoff valve device 30 are closed in the state where the indoor expansion valve 23 is closed, when the pressure in the liquid-side refrigerant pipes 461 to 463 rises to the operating pressure of the pressure relief valve 36, the pressure relief valve 36 opens and the pressure in the liquid-side refrigerant pipes 461 to 463 is released toward the gas-side refrigerant pipe 43. This makes it possible to prevent the liquid-side refrigerant pipes 461 to 463 from becoming the liquid sealed state, and prevent problems such as damage to the liquid-side refrigerant pipes 461 to 463 due to an excessive increase in refrigerant pressure.

[0066] However, if the pressure relief valve 36 experiences an initial malfunction or entrapment of foreign substances or the like and thus the liquid-side refrigerant pipe 461 communicates with the gas-side refrigerant pipe 43, the refrigerant will be allowed flow back from the gas-side refrigerant pipe 43 to the liquid-side refrigerant pipe 461. In this case, when the bypass path 35 is connected to the gas-side refrigerant pipes 431 and 432, which are closer to the outdoor unit 10 relative to the gas-side control valves 311 and 312, there is a risk that the refrigerant being recovered from each of the indoor units 201 to 203 toward the compressor 14 by the recovery processing described above will flow back through the pressure relief valve 36 and flow into the first liquid-side refrigerant pipe 461. In this case, the amount of refrigerant flowing back through the pressure relief valve 36 may be close to the total amount in the refrigeration cycle.

[0067] Therefore, in the present embodiment, the bypass path 35 connects one of the liquid-side refrigerant pipes 46 and 461 to 463 closer to the indoor units 201 to 203 relative to the liquid-side control valve 34 and one of the gas-side refrigerant pipes 43 to 45, 431, 432, 441, 442, 451, and 452 closer to the indoor units 201 to 203 relative to the gas-side control valves 311, 312, 321, 322, 331, and 332. In the example of Figure 1, the bypass path 35 connects the liquid-side refrigerant pipe 461, which is closer to the indoor unit 201 relative to the liquid-side control valve 34, and the gas-side refrigerant pipe 43, which is closer to the indoor unit 201 relative to the gas-side control valves 311 and 312.

[0068] Accordingly, even if the pressure relief valve 36 does not operate normally due to the initial malfunction or the entrapment of foreign substances or the like, the gas-side control valves 311 and 312 are closed, whereby it is possible to prevent the refrigerant recovered in the recovery processing from flowing back through the pressure relief valve 36. In this way, according to the air-conditioning device 1 of the present embodiment, it is possible to improve safety and reliability against the leakage of the refrigerant.

[0069] As shown in Figure 6, the pressure relief valve 36 is arranged vertically above a connection portion 351 between the bypass path 35 and the liquid-side refrigerant pipe 461 and a connection portion 352 between the bypass path 35 and the gas-side refrigerant pipe 43. This makes it possible to prevent foreign substances such as cooling water or contamination mixed in during the pipework of the air-conditioning device 1 from being stagnant near the pressure relief valve 36. In other words, according to the configuration of the present embodiment, even when a foreign substance of a size, which may cause an operational failure of the pressure relief valve 36, is mixed into the refrigerant, such a foreign substance can be prevented from reaching the pressure relief valve 36 against gravity, for example. This makes it possible to prevent the pressure relief valve 36 from causing the operational failure due to the entrapment of the foreign substance or the like, and as a result, to further improve safety and reliability against the leakage of the refrigerant.

[0070] Here, the pressure relief valve 36 is provided in the bypass path 35 to prevent liquid sealing, but if the indoor unit 201 is not connected to the refrigerant pipes 461 and 43 to which the bypass path 35 and the pressure relief valve 36 are connected, this will be the same as if the bypass path 35 and the pressure relief valve 36 do not exist. Regarding this, the inventors of the present application have focused that a worker connects each of the indoor units 201 to 203 to the refrigerant pipes in order, starting from the refrigerant pipe closest to the liquid-side control valve 34, during the pipework of the air-conditioning device 1. In other words, during the pipework of the air-conditioning device 1, the worker normally connects each of the indoor units 201 to 203 to the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43, the second liquid-side refrigerant pipe 462 and the second gas-side refrigerant pipe 44, and the third liquid-side refrigerant pipe 463 and the third gas-side refrigerant pipe 45 in this order.

[0071] Therefore, the bypass path 35 is provided at a position at which the refrigerant pipes are connected which are closest to the liquid-side control valve 34 among the plurality of liquid-side refrigerant pipes 461 to 463 and the plurality of gas-side refrigerant pipes 43 to 45, in this case, at a position at which the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43 are connected. This makes it easier to connect the indoor unit 201 to the first liquid-side refrigerant pipe 461 and the first gas-side refrigerant pipe 43 provided with the bypass path 35. For this reason, it is possible to prevent a situation in which the indoor unit 201 is not connected to the refrigerant pipes 461 and 43 to which the bypass path 35 and the pressure relief valve 36 are connected. As a result, since the bypass path 35 and the pressure relief valve 36 can function appropriately, it is possible to further improve safety and reliability against the leakage of the refrigerant.

[0072] In addition, the air-conditioning device 1 further includes the detection processing unit 171 and the report processing unit 172. The detection processing unit 171 detects the unconnected state in which the indoor unit 201 is not connected to the refrigerant pipes 461 and 43 in which the bypass path 35 is provided. The report processing unit 172 issues a report when the detection processing unit 171 detects the unconnected state. Accordingly, during the pipework of the air-conditioning device 1, the worker can more reliably know the unconnected state in which the indoor unit 201 is not connected to the refrigerant pipes 461 and 43 in which the bypass path 35 is provided. This makes it possible to more reliably prevent the situation in which the indoor unit 201 is not connected to the refrigerant pipes 461 and 43 to which the bypass path 35 and the pressure relief valve 36 are connected. As a result, since the bypass path 35 and the pressure relief valve 36 can function appropriately, it is possible to further improve safety and reliability against the leakage of the refrigerant.

[0073] The number of shutoff valve devices 30 provided in the air-conditioning device 1 is not limited to the above. For example, a plurality of shutoff valve devices 30 may be connected to form a single refrigeration cycle. Moreover, the number of indoor units connected to the shutoff valve device 30 is not limited to the above. As described above, the shutoff valve device 30 can also be lined up ranging from a model that can connect two indoor units to a model that can connect up to eight indoor units, and even more models.

[0074] Furthermore, it is not necessary to provide the leakage sensor 24 for all of the indoor units. For example, in a case where a plurality of indoor units are installed in the same space, it is sufficient to install at least one leakage sensor 24 in one space.

[0075] In the present embodiment, various types of processing such as the recovery processing when the refrigerant leaks out from the indoor unit of the air-conditioning device 1 are executed by the outdoor control unit 17, but these types of processing may be assigned to any controller that is connected with a communication line and is capable of sharing information. For example, if one of control units of the indoor units or the shutoff valve device 30 is set as a master and control units of the other devices including the outdoor control unit 17 are set as slaves, the same processing as the above-described control can be executed by an instruction from the control unit set as the master to the slave control units. Furthermore, a centralized management device that manages the air-conditioning device 1 as a whole may be communicably connected to a communication line between the indoor control unit 25 and the outdoor control unit 17, and various types of processing may be executed by this centralized management device during leakage of the refrigerant.

[0076] An embodiment of the present invention has been described, but this embodiment has been presented as an example and is not intended to limit the scope of the invention. These novel embodiments can be carried out in other various forms, and various omissions, replacements, changes, and combinations of the respective components and controls can be made without departing from the spirit of the invention. These embodiments and their modifications are involved in the scope and spirit of the invention and involved in the invention recited in the claims and an equivalent range thereof.Reference Signs List

[0077] 1 air-conditioning device 10 outdoor unit 11 outdoor heat exchanger 14 compressor 171 detection processing unit 172 report processing unit 201, 202, 203 indoor unit 21 indoor heat exchanger 30 shutoff valve device 311, 312, 321, 322, 331, 332 gas-side control valve 34 liquid-side control valve 35 bypass path 351, 352 connection portion 36 pressure relief valve

Claims

1. An air-conditioning device comprising: an outdoor unit including an outdoor heat exchanger and a compressor; a plurality of indoor units each including an indoor heat exchanger connected to the outdoor heat exchanger and the compressor; a plurality of liquid refrigerant flow passages through which a liquid refrigerant flows and a plurality of gas refrigerant flow passages through which a gaseous refrigerant flows, the plurality of liquid refrigerant flow passages and the plurality of gas refrigerant flow passages connecting the outdoor unit and the plurality of indoor units; and a shutoff valve device that is provided between the outdoor unit and the plurality of indoor units and is capable of controlling a flow of a refrigerant in the liquid refrigerant flow passages and the gas refrigerant flow passages, wherein the shutoff valve device includes a liquid-side control valve that is provided in common to the plurality of liquid refrigerant flow passages and is capable of shutting off the flow of the refrigerant through the plurality of liquid refrigerant flow passages, a gas-side control valve that is provided in each of the plurality of gas refrigerant flow passages and is capable of shutting off the flow of the refrigerant through the plurality of gas refrigerant flow passages, a bypass path that connects one of the liquid refrigerant flow passages closer to the indoor unit relative to the liquid-side control valve and one of the gas refrigerant flow passages closer to the indoor unit relative to the gas-side control valve, and a pressure relief valve that is provided on the bypass path and is normally in a closed state, and that when pressure reaches a preset pressure or higher, comes into an open state by operating using the pressure without using electric power to release pressure of the refrigerant from the liquid refrigerant flow passage to the gas refrigerant flow passage.

2. The air-conditioning device according to claim 1, wherein the pressure relief valve is arranged above a connection portion between the bypass path and the liquid refrigerant flow passage and a connection portion between the bypass path and the gas refrigerant flow passage in a vertical direction.

3. The air-conditioning device according to claim 1, wherein the bypass path is provided at a connection position between the liquid refrigerant flow passage and the gas refrigerant flow passage which are closest to the liquid-side control valve, among the plurality of liquid refrigerant flow passages and the plurality of gas refrigerant flow passages.

4. The air-conditioning device according to any one of claims 1 to 3, further comprising: a detection processing unit that detects an unconnected state in which the indoor unit is not connected to the liquid refrigerant flow passage and the gas refrigerant flow passage in which the bypass path is provided; and a report processing unit that issues a report when the detection processing unit detects the unconnected state.

5. The air-conditioning device according to any one of claims 1 to 3, further comprising a backup power supply that supplies power to the liquid-side control valve and the gas-side control valve.

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