Valve unit and method for assembling the same

Abstract

Provided is a valve unit (100) for a heat pump system, including: at least one liquid refrigerant pipe portion (210, 211); at least one gas refrigerant pipe portion (220, 221, 230, 240, 241); at least one liquid control valve (264) disposed in the liquid refrigerant pipe portion; at least one gas control valve (261, 262, 265) disposed in the gas refrigerant pipe portion; a housing (300) that houses at least the liquid control valve and the gas control valve; and an air discharge mechanism (500) configured to discharge air in an internal space (301) of the housing to an external space outside the housing when refrigerant leakage occurs in the housing.

Description

TECHNICAL FIELD

[0001] The present application relates to a valve unit for a heat pump system and a method of assembling the valve unit. BACKGROUND

[0002] EP3091314A1 proposes a valve unit for a heat pump system. The valve unit includes a liquid control valve arranged in a liquid refrigerant pipe, a gas control valve arranged in a gas refrigerant pipe, and a housing covering the liquid control valve and the gas control valve. Each valve tends to become a leakage point of refrigerant, and therefore, a monitoring person needs to check it periodically, and a maintenance person needs to repair it if necessary.

[0003] However, when a refrigerant leakage occurs, a large amount of leaked refrigerant can have penetrated in the internal space of the housing by the time the monitoring / maintenance person arrives and opens the housing. Some refrigerants used are flammable or slightly flammable, for example. Therefore, it is undesirable to open such a housing from a safety point of view. At the same time, if the valves are not covered by the housing, the leaked refrigerant will immediately spread to the surrounding area. SUMMARY

[0004] An object of the present application is to provide a valve unit having high safety against refrigerant leakage, and to provide a method of assembling the valve unit.

[0005] A first aspect of the present application provides a valve unit for a heat pump system, comprising: at least one liquid refrigerant pipe portion; at least one gas refrigerant pipe portion; at least one liquid control valve arranged in the liquid refrigerant pipe portion; at least one gas control valve arranged in the gas refrigerant pipe portion; a housing accommodating at least the liquid control valve and the gas control valve; and an air discharge mechanism configured to discharge air in an internal space of the housing to an external space outside the housing when a refrigerant leakage occurs in the housing.

[0006] With the above configuration, even if a refrigerant leakage occurs at the valves, the housing can prevent or suppress the leaked refrigerant from spreading to the surrounding area. Furthermore, by discharging the air in the internal space to the external space of the housing, the concentration of the leaked refrigerant in the internal space of the housing can be reduced. The external space is preferably not an external space directly surrounding the housing or an indoor space in which humans or animals can enter or reside. The external space is preferably an outdoor space.

[0007] Further, the valve unit can be configured such that the inside space of the casing is substantially closed at ordinary times, and the refrigerant leakage detection can be performed based on the refrigerant concentration in the inside space of the casing. In this case, it is possible to quickly detect the occurrence of the refrigerant leakage in the casing and to start the operation of the air discharge mechanism at an early stage. Therefore, it is possible to prevent the concentration of the leaked refrigerant in both the casing and the surrounding area in a safer manner. This allows the monitoring / maintenance personnel to safely monitor, maintain, or repair the valve. Therefore, it is possible to improve the safety of the valve unit with respect to the refrigerant leakage.

[0008] The piping portion, the valve, and the casing, and preferably the air discharge mechanism, can be manufactured together. In this case, it is easier to design the valve unit to improve its performance, such as the air tightness of the casing and the air discharge efficiency of the air discharge mechanism. It is also easier to optimize the size of the valve unit, the position of the maintenance door of the casing, and the capacity of the air discharge mechanism. Therefore, it is possible to improve not only the safety but also the maintainability and functionality of the valve unit. Alternatively, the casing can be a retrofitted casing to be assembled around an existing valve.

[0009] According to another preferred embodiment of the valve unit having a fan as described above, the air discharge mechanism further includes a check air damper configured to allow air to flow from the outside of the casing to the inside space through the opening when the fan is operated.

[0010] With the above configuration, when the refrigerant leakage occurs in the casing, the air in the casing can be effectively discharged. In the case where the casing has a portion exposed to the outdoor space, the outlet of the fan can be arranged in the portion. In the case where the casing has no portion exposed to the outdoor space, an air duct extending from the casing to the outdoor space can be arranged, and the fan can be arranged in or attached to the air duct. It is preferable that the fan be arranged at the outer end of the air duct. Therefore, the entire air duct can be kept under pressure, thereby preventing the air containing the refrigerant from leaking from the duct.

[0011] According to another preferred embodiment of the valve unit having a fan as described above, the air discharge mechanism further includes a check air damper configured to allow air to flow from the outside of the casing to the inside space through the opening when the fan is operated.

[0012] With the above configuration, the air discharge in the inside space of the casing can be facilitated by replacement with the outside air. Therefore, when the refrigerant leakage occurs in the casing, the air in the casing can be more effectively discharged. Further, since the check air damper can be kept in the closed state when the fan is not operated, it is possible to maintain the air tightness of the casing.

[0013] According to another preferred embodiment of any of the valve units as described above, the valve unit further comprises a sensor configured to detect a concentration of refrigerant in the air of the housing, and a controller configured to determine that a refrigerant leakage has occurred in the housing when the detected concentration is equal to or greater than a threshold value of detection, and to control the air discharge mechanism to start operating when the refrigerant leakage has occurred.

[0014] With the above configuration, even when a refrigerant leakage occurs in the housing, the refrigerant concentration in the internal space of the housing can be prevented from becoming high. Thus, the safety of the valve unit can be achieved in a safer manner.

[0015] According to another preferred embodiment of any of the valve units with a controller as described above, the liquid refrigerant pipe portion and the gas refrigerant pipe portion are formed in a part of a liquid refrigerant pipe and a part of a gas refrigerant pipe that extend between a heat source side heat exchanger and a utilization side heat exchanger of a heat pump system, respectively. The controller is further configured to control the liquid control valve and the gas control valve to be closed when a refrigerant leakage occurs in a utilization side pipe section that extends between the liquid control valve and the gas control valve and that includes at least the utilization side heat exchanger.

[0016] With the above configuration, when a refrigerant leakage occurs in the utilization side pipe section, the further supply of refrigerant to the utilization side pipe section can be limited or stopped. Thus, further leakage of refrigerant from the utilization side pipe section, e.g., from the utilization side heat exchanger, can be limited or prevented. The liquid control valve and the gas control valve are preferably stop valves. Further, the refrigerant circuit of the heat pump system can be divided into smaller portions that are arranged for different spaces. There are cases where the ratio of the total amount of refrigerant in each circuit section to the total volume of the space to which the circuit section extends is subject to legal restrictions. Even in such cases, the above configuration allows the air conditioning system to be easily applied to facilities with relatively small spaces while ensuring high safety at low cost. Further, although the valves themselves can be refrigerant leakage points, they are also arranged within the housing. Thus, the effects as described above can be obtained without affecting the safety of refrigerant leakage at other locations.

[0017] According to another preferred embodiment of the valve unit with a check damper and a controller as described above, the check damper is configured to be operated by an electric motor, and the controller is configured to control the electric motor to open the check damper when a refrigerant leakage occurs in the housing.

[0018] With the above configuration, when a refrigerant leakage occurs in the housing, the air in the housing can be more effectively and safely discharged.

[0019] According to another preferred embodiment of any one of the valve units having the controller as described above, the controller is further configured to output an alarm when a refrigerant leakage occurs in the housing or a refrigerant leakage occurs in the utilization-side pipe section.

[0020] With the above configuration, the refrigerant leakage in the housing or the utilization-side pipe section can be notified to the monitoring / maintenance personnel and / or the external information output device. Thus, the safety of the valve unit and / or the air conditioning system can be further improved.

[0021] According to another preferred embodiment of any one of the valve units as described above, the at least one gas refrigerant pipe section includes a low-pressure gas pipe section, a high-pressure gas pipe section, and a utilization-side gas pipe section branched into the low-pressure gas pipe section and the high-pressure gas pipe section. The at least one liquid control valve includes a liquid shut-off valve disposed in the liquid refrigerant pipe section. The at least one gas control valve includes a low-pressure gas control valve disposed in the low-pressure gas pipe section, a high-pressure gas control valve disposed in the high-pressure gas pipe section, and a gas shut-off valve disposed in the utilization-side gas pipe section.

[0022] With the above configuration, the valve unit can switch whether the utilization-side gas pipe section communicates with the low-pressure gas pipe section or the high-pressure gas pipe section.

[0023] For example, the liquid refrigerant pipe section selectively communicates with a condenser and an evaporator as heat-source-side heat exchangers disposed in a heat-source-side unit, and with a utilization-side heat exchanger disposed in a utilization-side unit. The low-pressure gas pipe section communicates with a suction port of a refrigerant compressor disposed in the heat-source-side unit. The high-pressure gas pipe section communicates with a discharge port of the refrigerant compressor disposed in the heat-source-side unit. The utilization-side gas pipe section communicates with the utilization-side heat exchanger. In this case, the valve unit can function as a branch selector that allows an operating state of the utilization-side unit to be easily switched between a cooling operation in which the utilization-side heat exchanger functions as an evaporator and a heating operation in which the utilization-side heat exchanger functions as a condenser.

[0024] According to another preferred embodiment of any one of the valve units as described above, the at least one liquid refrigerant pipe section includes a plurality of utilization-side liquid pipe sections and a heat-source-side liquid pipe section branched into the utilization-side liquid pipe sections. The at least one gas refrigerant pipe section includes a plurality of utilization-side gas pipe sections and a heat-source-side gas pipe section branched into the utilization-side gas pipe sections. The at least one liquid control valve includes a plurality of liquid shut-off valves respectively disposed in the utilization-side liquid pipe sections, and the at least one gas control valve includes a plurality of gas shut-off valves respectively disposed in the utilization-side gas pipe sections.

[0025] By the above configuration, the plurality of utilization-side gas pipe portions are connected to the common heat-source-side gas pipe portion, and the plurality of utilization-side liquid pipe portions are connected to the common heat-source-side liquid pipe portion.

[0026] For example, the heat-source-side liquid pipe portion communicates with a heat-source-side heat exchanger arranged in the heat-source-side unit. The utilization-side liquid pipe portions respectively communicate with a plurality of utilization-side heat exchangers arranged in the plurality of utilization-side units. The heat-source-side gas pipe portion communicates with a refrigerant compressor arranged in the heat-source-side unit. The utilization-side gas pipe portions respectively communicate with the utilization-side heat exchangers. In this case, the valve unit can function as a refrigerant branching unit that allows the plurality of utilization-side units to share the common heat-source-side unit.

[0027] According to another preferred embodiment of any one of the valve units described above, the at least one liquid refrigerant pipe portion includes a plurality of utilization-side liquid pipe portions and a heat-source-side liquid pipe portion branching into the utilization-side liquid pipe portions. The at least one gas refrigerant pipe portion includes a plurality of low-pressure gas sub-pipe portions, a low-pressure gas pipe portion branching into the low-pressure gas sub-pipe portions, a plurality of high-pressure gas sub-pipe portions, a high-pressure gas pipe portion branching into the high-pressure gas sub-pipe portions, and a plurality of utilization-side gas pipe portions respectively branching into one of the low-pressure gas sub-pipe portions and one of the high-pressure gas sub-pipe portions to be connected to the low-pressure gas pipe portion and the high-pressure gas pipe portion via the low-pressure gas sub-pipe portion and the high-pressure gas sub-pipe portion, respectively. The at least one liquid control valve includes a plurality of liquid shut-off valves respectively arranged in the utilization-side liquid pipe portions. The at least one gas control valve includes a plurality of low-pressure gas control valves respectively arranged in the low-pressure gas sub-pipe portions, a plurality of high-pressure gas control valves respectively arranged in the high-pressure gas sub-pipe portions, and a plurality of gas shut-off valves respectively arranged in the utilization-side gas pipe portions.

[0028] By the above configuration, the valve unit can function as a multi-connected branching selector in which the functions of the branching selector and the refrigerant branching unit described above are integrated. The multi-connected branching selector shares the same heat-source-side unit while realizing individual air conditioning of the plurality of utilization-side units. Meanwhile, the multi-connected branching selector tends to include a plurality of branching / merging points and valves, and thus has many possible refrigerant leakage points. By the above configuration, a large number of possible refrigerant leakage points can be arranged inside the housing.

[0029] According to another preferred embodiment of any one of the valve units described above, the valve unit further includes an insulator applied to the housing, the insulator insulating an internal space of the housing from an external space around the housing at least when the air discharging mechanism is not operating.

[0030] With the above configuration, at least when the air discharging mechanism is not operating, the inside space of the casing can be substantially closed. Therefore, when a refrigerant leakage occurs at the valve, the leaked refrigerant can be prevented from spreading to the surrounding area, and the refrigerant leakage occurring in the casing can be detected more quickly.

[0031] According to another preferred embodiment of any one of the valve units having a low-pressure gas control valve and a high-pressure gas control valve as described above, a minute passage is formed in at least one of the low-pressure gas control valve and the high-pressure gas control valve, the minute passage being configured and arranged to allow a refrigerant to flow therethrough even when an opening degree of the at least one of the low-pressure gas control valve and the high-pressure gas control valve is set to a minimum opening degree.

[0032] With the above configuration, by the minute passage, it is possible to prevent a liquid seal circuit from being formed in the refrigerant circuit without separately providing a bypass circuit for preventing a liquid seal. Therefore, it is possible to improve the reliability of the air conditioning system at a low cost.

[0033] According to another preferred embodiment of any one of the valve units as described above, the refrigerant is an R32 refrigerant.

[0034] The R32 refrigerant is also referred to as an HFC-32 refrigerant or a difluoromethane refrigerant, has a chemical formula of CH2F2, has characteristics of zero ozone depletion potential and low global warming potential, and has slight flammability. Therefore, it is possible to realize an environmentally friendly air conditioner while ensuring high safety in terms of refrigerant leakage.

[0035] A second aspect of the present application provides a method for assembling any one of the valve units as described above, in which the casing is formed of a plurality of casing members, the method including: arranging the casing members around at least the liquid control valve and the gas control valve; and fixing the casing members to each other.

[0036] With the above steps, it is possible to realize the effects of any one of the valve units as described above using existing liquid control valves and gas control valves. The method can further include assembling a unit having a liquid refrigerant pipe portion, a gas refrigerant pipe portion, a liquid control valve, and a gas control valve before arranging the casing members.

[0037] According to another preferred embodiment of the method as described above, the method further includes attaching the air discharging mechanism to the casing.

[0038] With the above steps, it is possible to separately assemble the air discharging mechanism to the casing before or after the casing members are fixed to each other. BRIEF DESCRIPTION OF DRAWINGS

[0039] Figure 1A schematic configuration diagram of a valve unit according to the embodiment of the present application is shown.

[0040] Figure 2 A block diagram showing the functional configuration of the controller is shown. Figure 1

[0041] Figure 3 A flowchart showing the steps performed by the controller is shown.

[0042] Figure 4 A schematic configuration diagram of a valve unit according to the modification of the present embodiment is shown. DETAILED DESCRIPTION

[0043] With reference to the drawings, a preferred embodiment of a valve unit according to the present application (hereinafter, referred to as "the present embodiment") will be described. For example, the valve unit according to the present embodiment is used for a multi-connected air conditioning system having a so-called three-pipe configuration, which includes a heat source-side unit and a plurality of utilization-side units, and uses an R32 refrigerant.

[0044] Configuration of the unit

[0045] Figure 1 A schematic configuration diagram of a valve unit according to the present embodiment is shown.

[0046] As shown in Figure 1 The valve unit 100 includes a multi-connected branch selector 200, a casing 300, a sensor 400, an air discharging mechanism 500, and a controller 600. The casing 300 accommodates the multi-connected branch selector 200 therein. The air discharging mechanism 500 is mounted on or connected to the casing 300. In the present embodiment, the air discharging mechanism 500 includes a fan 510 and a check damper 520. The sensor 400 and the controller 600 are arranged in an internal space 301 of the casing 300. However, the controller 600 can be arranged on or outside the casing 300.

[0047] The multi-connected branch selector 200 includes a heat source-side liquid pipe portion 210, a plurality of utilization-side liquid pipe portions 211, a low-pressure gas pipe portion 220, a plurality of low-pressure gas sub-pipe portions 221, a plurality of utilization-side gas pipe portions 230, a high-pressure gas pipe portion 240, a plurality of high-pressure gas sub-pipe portions 241, a plurality of bypass pipes 251, and a plurality of refrigerant heat exchangers 252. The multi-connected branch selector 200 further includes a plurality of low-pressure gas control valves 261, a plurality of high-pressure gas control valves 262, a plurality of expansion mechanisms 263, a plurality of liquid shutoff valves 264, and a plurality of gas shutoff valves 265.

[0048] ​The number of the utilization-side liquid pipe portions 211, the low-pressure gas sub-pipe 221, the utilization-side gas pipe portions 230, the high-pressure gas sub-pipe 241, the bypass pipe 251, the refrigerant heat exchanger 252, the low-pressure gas control valve 261, the high-pressure gas control valve 262, the expansion mechanism 263, the liquid shut-off valve 264, and the gas shut-off valve 265 can be the same. One of the utilization-side liquid pipe portions 211 and one of the utilization-side gas pipe portions 230 communicate with the same utilization-side heat exchanger. Therefore, the above number can correspond to the number of the utilization-side units (not shown) of the heat pump system. The above number is not limited to a specific number.

[0049] The heat-source-side liquid pipe portion 210 communicates with each of a condenser and an evaporator (heat-source-side heat exchanger) in the heat-source-side unit (not shown) disposed outside the casing 300. The heat-source-side liquid pipe portion 210 is branched into the utilization-side liquid pipe portions 211 in the multi-branch selector 200. The utilization-side liquid pipe portions 211 respectively communicate with a plurality of utilization-side heat exchangers in the utilization-side units (not shown) disposed outside the casing 300.

[0050] In other words, the heat-source-side liquid pipe portion 210 and each of the utilization-side liquid pipe portions 211 form a part of a liquid refrigerant pipe of the heat pump system.

[0051] The low-pressure gas pipe portion 220 communicates with a suction side of a refrigerant compressor (not shown) in the heat-source-side unit disposed outside the casing 300. The low-pressure gas pipe portion 220 is branched into the low-pressure gas sub-pipes 221 in the multi-branch selector 200. The low-pressure gas sub-pipes 221 are respectively connected to the utilization-side gas pipe portions 230. The utilization-side gas pipe portions 230 respectively communicate with the utilization-side heat exchangers in the utilization-side units disposed outside the casing 300. It can also be explained that the low-pressure gas pipe portion 220 is branched into the utilization-side gas pipe portions 230 via the low-pressure gas sub-pipes 221.

[0052] In other words, the low-pressure gas pipe portion 220, each of the low-pressure gas sub-pipes 221, and each of the utilization-side gas pipe portions 230 form a part of a low-pressure gas refrigerant pipe of the heat pump system.

[0053] The high-pressure gas pipe portion 240 communicates with the discharge side of the refrigerant compressor outside the casing 300. The high-pressure gas pipe portion 240 is branched into high-pressure gas sub-pipe portions 241 in the multi-branch selector 200. The high-pressure gas sub-pipe portions 241 are connected to the utilization-side gas pipe portions 230, respectively. It can also be explained that the high-pressure gas pipe portion 240 is branched into the utilization-side gas pipe portions 230 via the high-pressure gas sub-pipe portions 241. It can also be said that each of the utilization-side gas pipe portions 230 is branched into the low-pressure gas pipe portion 220 and the high-pressure gas pipe portion 240 via one of the low-pressure gas sub-pipe portions 221 and one of the high-pressure gas sub-pipe portions 241.

[0054] In other words, the high-pressure gas pipe portion 240, each of the high-pressure gas sub-pipe portions 241, and each of the utilization-side gas pipe portions 230 form a part of a high-pressure gas refrigerant pipe of the heat pump system.

[0055] The bypass pipes 251 are connected to the utilization-side liquid pipe portions 211, respectively, and to the low-pressure gas pipe portion 220, respectively. In other words, each of the bypass pipes 251 is branched from one of the utilization-side liquid pipe portions 211 and merged into the low-pressure gas pipe portion 220.

[0056] The expansion mechanisms 263 are disposed in the bypass pipes 251, respectively. Each of the expansion mechanisms 263 is configured to depressurize and expand the refrigerant flowing out of the corresponding utilization-side liquid pipe portion 211 in the bypass pipe 251. Each of the expansion mechanisms 263 can be an electric expansion valve.

[0057] The refrigerant heat exchangers 252 are provided to the bypass pipes 251, respectively. Each of the refrigerant heat exchangers 252 is configured to exchange heat between the refrigerant flowing in one of the utilization-side liquid pipe portions 211 and the refrigerant that has been depressurized and expanded by the corresponding expansion mechanism 263 and is flowing in the corresponding bypass pipe 251. In other words, each of the refrigerant heat exchangers 252 forms a subcooling system in combination with the corresponding utilization-side liquid pipe portion 211, bypass pipe 251, and expansion mechanism 263. Each of the refrigerant heat exchangers 252 can have two flow passages that respectively form a part of the utilization-side liquid pipe portion 211 and a part of the bypass pipe 251, and there is heat conduction between them.

[0058] The low-pressure gas control valves 261 are disposed in the low-pressure gas sub-pipe portions 221, respectively. Each of the low-pressure gas control valves 261 is configured to be switched between an open state and a closed state, i.e., whether to allow the refrigerant to flow between the low-pressure gas pipe portion 220 and the corresponding utilization-side gas pipe portion 230. The state of each of the low-pressure gas control valves 261 is controlled by the controller 600 in accordance with the required operation mode of the corresponding utilization-side unit. Each of the low-pressure gas control valves 261 can be an electric valve.

[0059] High-pressure gas control valves 262 are respectively arranged in the high-pressure gas sub-pipes 241. Each high-pressure gas control valve 262 is configured to switch between an open state and a closed state, i.e., whether to allow the refrigerant to flow between the high-pressure gas pipe portion 240 and the corresponding utilization-side gas pipe portion 230. The state of each high-pressure gas control valve 262 is controlled by the controller 600 in accordance with, for example, the operation mode required by the corresponding utilization-side unit. Each high-pressure gas control valve 262 can be an electric valve.

[0060] Preferably, a minute passage is formed in each low-pressure gas control valve 261 and / or each high-pressure gas control valve 262. The minute passage is configured and arranged such that the refrigerant can flow through the minute passage even when the opening degree of the valve is set to the minimum.

[0061] Liquid shut-off valves 264 are respectively arranged in the utilization-side liquid pipe portions 211. Gas shut-off valves 265 are respectively arranged in the utilization-side gas pipe portions 230. The liquid shut-off valve 264 and the gas shut-off valve 265 arranged in the utilization-side liquid pipe portion 211 and the utilization-side gas pipe portion 230 that communicate with the same utilization-side heat exchanger define a utilization-side piping section that extends between the two and includes at least the utilization-side heat exchanger. Each of the liquid shut-off valve 264 and the gas shut-off valve 265 can be an electric valve.

[0062] The housing 300 can have a substantially box-type shape, and be large enough to accommodate the multi-branch selector 200 therein. The housing 300 can be made of a metal plate, a carbon fiber plate, a flame-retardant resin plate, or the like. The housing 300 is formed with a plurality of pipe holes 310, a discharge opening 320, and an intake opening 330. Preferably, the housing 300 includes a plurality of housing components that can be connected and detached from each other. In this case, the structure of the housing components can be such that each pipe hole 310 is formed between two or more adjacent housing components.

[0063] The plurality of pipe holes 310 are configured to allow respective extension pipes (hereinafter, referred to as "extension pipes") extending from the multi-branch selector 200 to pass therethrough. In other words, the plurality of pipe holes 310 are formed at positions corresponding to the positions of the extension pipes, and the diameter of each pipe hole 310 is larger than the diameter of the corresponding extension pipe. In the case where each pipe hole 310 is formed as described above between two or more housing components, each extension pipe can be easily fitted into the corresponding pipe hole 310 when the housing components are assembled. Here, such extension pipes include the heat-source-side liquid pipe portion 210, the low-pressure gas pipe portion 220, the high-pressure gas pipe portion 240, the utilization-side liquid pipe portion 211, and the utilization-side gas pipe portion 230.

[0064] Each extension piping may have a piping connection component 270 for connecting to other portions of the corresponding external piping, namely, the liquid refrigerant piping of the heat pump system, the low-pressure gas refrigerant piping, and the high-pressure gas refrigerant piping. Preferably, the piping connection component 270 is located outside the housing 300.

[0065] The discharge opening 320 is configured to allow air in the internal space 301 of the housing 300 (hereinafter referred to as "internal air") to pass through the external space outside the housing 300 via the suction force of the fan 510. Figure 1 As shown, the fan 510 is disposed outside the housing 300, and the suction port of the fan 510 is connected to the discharge opening 320 of the housing 300 via an air duct 511, which is also part of the air emission mechanism 500. Preferably, the discharge port of the fan 510 faces the outdoor space. Alternatively, the fan 510 can be mounted on the housing 300 at the discharge opening 320, such that the suction port of the fan 510 faces the interior space 301 of the housing 300, and the discharge port of the fan 510 faces the exterior of the housing 300. The fan 510 can also be disposed inside the housing. In this case, the discharge opening 320 can be connected to the discharge port of the fan 510 via an internal air duct, which is also part of the air emission mechanism 500.

[0066] The air intake opening 330 is configured to allow air to flow from the outside of the housing 300 to the internal space 301 of the housing 300 through the backflow preventer 520. For example... Figure 1 As shown, the backflow preventer 520 can be installed on the housing 300 at the air inlet opening 330. Alternatively, in an arrangement where the backflow preventer 520 is located inside the housing, the air inlet opening 330 can be connected to the backflow preventer 520 via an air duct, which is also part of the air exhaust mechanism 500. In an arrangement where the backflow preventer 520 is located outside the housing, the air inlet opening 330 can be connected to the backflow preventer 520 via an air duct, which is also part of the air exhaust mechanism 500.

[0067] The housing 300 preferably has a maintenance door (not shown) configured to allow monitoring / maintenance personnel to inspect the status of the multi-gang branch selector 200 and / or, as needed, to perform maintenance on the multi-gang branch selector 200 through the open door.

[0068] An isolator is applied to housing 300 to isolate the internal space 301 of housing 300 from the external space surrounding housing 300, at least when air exhaust mechanism 500 is not in operation. The isolator may include isolator 340, which respectively fits in the gap between the outer surface of the extension piping of multi-branch selector 200 and the inner edge of piping port 310.

[0069] Each of the insulators 340 can be a foam tube, a foam wrap, a foam filler, a caulking material, a tape, or the like. The foam tube having a cutting line extending in the axial direction thereof is easy to fit into the gap. The thickness of the foam tube is preferably equal to or slightly greater than the gap between the outer surface of the corresponding extension pipe and the inner surface of the corresponding pipe hole 310. The insulator 340 can be attached to the extension pipe before the housing 300 is assembled. The insulator can also be applied to other gaps in the housing 300, such as the gap between the fan 510 and the air discharge opening 320, the gap between the non-return damper 520 and the air intake opening 330, the gap between adjacent housing components, and the gap between the maintenance door and the housing 300.

[0070] The sensor 400 is disposed in the internal space 301 of the housing 300. In the case where the refrigerant, such as R32 refrigerant, is heavier than air, the sensor 400 is preferably disposed on or near the inner bottom surface of the housing 300. The sensor 400 is configured to detect the concentration of the refrigerant in the air around the sensor 400 and output a detection value indicative of the detected concentration to the controller 600 by way of a signal. The sensor 400 can output the detection value (hereinafter referred to as "sensor detection value Vs") continuously or periodically. The sensor 400 can be a semiconductor gas sensor that reacts to the refrigerant used in the heat pump system.

[0071] As described later, it is determined by the controller 600 based on the detection value Vs whether or not a refrigerant leakage (hereinafter referred to as "refrigerant leakage") has occurred in the housing 300. However, the sensor 400 can have a function of making the determination by itself.

[0072] The air discharge mechanism 500 is configured to discharge the internal air to the outside of the housing 300 when the refrigerant leakage has occurred. As described above, the air discharge mechanism 500 includes the fan 510 and the non-return damper 520.

[0073] The fan 510 is controlled by the controller 600 as described later to suck the internal air of the housing 300 to the outside of the housing 300 when the refrigerant leakage has occurred. As described above, depending on the position of the fan 510, the air duct 511 is disposed between the fan 510 and the discharge opening 320. The fan 510 can also be provided with a non-return damper configured to prevent air from passing through the fan 510 when the fan 510 is not operating.

[0074] The check damper 520 is configured to allow air to flow from the outside of the casing 300 to the inside space 301 of the casing 300 through the intake opening 330 when the fan 510 is operating. As described above, depending on the position of the check damper 520, an air duct can be arranged between the check damper 520 and the intake opening 330. The check damper 520 is also configured to prevent the inside air from flowing out through the intake opening 330 when the fan 510 is not operating.

[0075] More specifically, the check damper 520 has a flap arranged in an air path through the intake opening 330. The flap is configured to switch between a closed position at which the flap air path is substantially closed and an open position at which the flap is displaced toward the inside space 301 side without closing the air path. The check damper 520 also has a force applying device such as a spring that applies force to the flap from the inside space 301 side toward the closed position. The force applying device has a force strength by which the flap is kept in the closed position when the fan 510 is not operating and is moved to the open position and kept in the open position by the suction force of the fan 510 when the fan 510 is operating.

[0076] Alternatively, the force applying device can be an electric motor controlled by the controller 600 as described later to keep the flap in the closed position at normal times and to move the flap to the open position when a refrigerant leakage has occurred. In other words, the check damper 520 can be an electrically controlled damper configured to be operated by an electric motor (not shown), and the controller 600 described above is configured to control the electric motor to open the check damper 520 when a refrigerant leakage has occurred. In this case, the open position of the flap is not limited to the position described above.

[0077] The casing 300 and the air discharge mechanism 500 are preferably configured such that the distance between the position at which the outside air flows into the inside space 301 and the position at which the inside air flows out of the inside space 301 is long enough to effectively ventilate the inside space 301. For example, the discharge opening 320 and the intake opening 330 are arranged on opposite sides of the casing 300 with respect to the central portion of the inside space 301.

[0078] The controller 600 is configured to control the operation of the valve unit 100 via a wired / wireless communication path (not shown) between the controller 600 and the machine equipment in the valve unit 100. Specifically, the controller 600 is configured to acquire the sensor detection value Vs from the sensor 400, and determine whether a refrigerant leakage has occurred based on the sensor detection value Vs. When a refrigerant leakage has occurred, the controller 600 is configured to start the operation of the air discharging mechanism 500. More specifically, the controller 600 is configured to start the operation of the fan 510. In the case where the non-return damper 520 has the electric motor as described above, the controller 600 is further configured to control the electric motor so that the flap is moved from the closed position to the open position.

[0079] Further, the controller 600 is preferably configured to control the liquid stop valve 264 and the gas stop valve 265 defining the utilization-side pipe section to be closed when a refrigerant leakage has occurred in any of the utilization-side pipe sections. The controller 600 can also output an alarm information when a refrigerant leakage has occurred in the body 300 or in any of the utilization-side pipe sections.

[0080] Although not shown, the controller 600 includes an arithmetic circuit such as a CPU (Central Processing Unit), a work memory such as a RAM (Random Access Memory) for use by the CPU, and a recording medium such as a ROM (Read Only Memory) storing a control program and information for use by the CPU. The controller 600 is configured to perform information processing and signal processing to control the operation of the valve unit 100 by the CPU executing the control program. Details of the controller 600 will be described later.

[0081] According to the valve unit 100 having the configuration as described above, when a refrigerant leakage has occurred in the multi-connected branch selector 200, the occurrence of the refrigerant leakage can be quickly detected, and the inside air of the housing 300 accommodating the multi-connected branch selector 200 is discharged to reduce the concentration of the leaked refrigerant in the internal space 301.

[0082] Functional configuration of controller

[0083] Figure 2 is a block diagram showing the functional configuration of the controller 600.

[0084] As shown in Figure 2 , the controller 600 includes a storage section 610, a detection value acquisition section 620, a unit control section 630, an information output section 640, and a leakage detection section 650.

[0085] The storage section 610 stores information in a form that can be read by the leakage detection section 650. The stored information includes a detection value threshold Vth used to determine whether a refrigerant leakage has occurred. The above-mentioned detection value threshold Vth is determined in advance through experiments or the like so as to avoid false detection and detection negligence of refrigerant leakage as much as possible. The storage section 610 can further store information indicating the relationship between the valve and the utilization-side unit and / or the utilization-side piping section.

[0086] The detection value acquisition section 620 is configured to acquire the sensor detection value Vs outputted from the sensor 400 continuously or periodically (see Figure 1 ). The detection value acquisition section 620 can request the sensor 400 to output the sensor detection value Vs periodically. When the concentration of the sensor reactive substance (i.e., the leaked refrigerant) in the internal space 301 changes, the sensor detection value Vs reflects the change substantially in real time. The detection value acquisition section 620 is configured to pass the acquired sensor detection value Vs to the leakage detection section 650.

[0087] The unit control section 630 is configured to control the opening degree of the low-pressure gas control valve 261, the high-pressure gas control valve 262, and / or the expansion mechanism 263 (see Figure 1 ). For example, for the piping connected to the utilization-side unit that should perform the cooling operation, the unit control section 630 controls the corresponding low-pressure gas control valve 261 and the expansion mechanism 263 to be opened, and controls the corresponding high-pressure gas control valve 262 to be closed. For the piping connected to the utilization-side unit that should perform the heating operation, the unit control section 630 controls the corresponding high-pressure gas control valve 262 to be opened, and controls the corresponding low-pressure gas control valve 261 and the expansion mechanism 263 to be closed. The unit control section 630 can perform the operation based on a signal indicating the desired operation mode of the utilization-side unit transmitted from the heat source-side unit, the utilization-side unit, and / or an information output device used by the monitoring / maintenance personnel.

[0088] The unit control section 630 is further configured to control the operation of the air discharge mechanism 500, the liquid shutoff valve 264, and the gas shutoff valve 265 (see Figure 1 ) according to the instruction from the leakage detection section 650. For example, the unit control section 630 controls the operation of the air discharge mechanism 500 by controlling the power supply to the air discharge mechanism 500.

[0089] The information output section 640 is configured to output alarm information indicating the occurrence of refrigerant leakage in accordance with an instruction from the leakage detection section 650. The information output section 640 outputs the alarm information by means of sound, light, and / or a visual image. The information output section 640 can be a speaker, an electric lamp, and / or a display device. The information output section 640 can include a communication interface device, and is configured to transmit an alarm signal indicating the alarm information to an external device, such as the heat source-side unit, the utilization-side unit, and / or an information output device used by a monitoring / maintenance person.

[0090] The leakage detection section 650 is configured to perform the judgment of refrigerant leakage and the required safety measures. The leakage detection section 650 includes a leakage judgment section 651 and a safety measure section 652.

[0091] The leakage judgment section 651 is configured to compare the sensor detection value Vs and the detection value threshold Vth continuously or periodically. The leakage judgment section 651 is configured to judge that refrigerant leakage has occurred if the sensor detection value Vs is equal to or greater than the detection value threshold Vth. The leakage judgment section 651 is configured to notify the safety measure section 652 of the result of this judgment.

[0092] The leakage judgment section 651 can be further configured to input a signal indicating the occurrence of refrigerant leakage when refrigerant leakage has occurred in any of the utilization-side pipe sections. This signal can be output by a refrigerant leakage detector provided in the corresponding utilization-side unit or by a refrigerant leakage detector provided in the space in which air conditioning is performed by the corresponding utilization-side unit. In this case, when the signal is input, the leakage judgment section 651 is configured to notify the safety measure section 652 of information indicating the utilization-side unit or the utilization-side pipe section in which refrigerant leakage has occurred.

[0093] The safety measure section 652 is configured to take the required safety measures via the unit control section 630 when the leakage judgment section 651 judges that refrigerant leakage has occurred in the casing 300. These safety measures include causing the operation of the air discharge mechanism 500 to start. More specifically, the safety measure section 652 provides an instruction to the unit control section 630 to cause the operation of the fan 510 to start, and also controls the check damper 520 to open if the check damper 520 is operated by an electric motor (see FIG. 6). Figure 1 ).

[0094] The safety measures can also include outputting alarm information by using the information output section 640 and / or transmitting an alarm signal indicating the alarm information.

[0095] The alarm signal can include an evacuation signal transmitted to the controller of the heat source-side unit via a wired / wireless communication path (not shown). The controller of the heat source-side unit (not shown) can be configured to execute an evacuation operation upon receiving the evacuation signal. In the evacuation operation, the following steps are executed: a shut-off valve (not shown) provided in the liquid refrigerant pipe is closed; the refrigerant compressor is operated until a predetermined condition is satisfied, for example, until some parameter indicates the end of the evacuation; and shut-off valves (not shown) provided in the low-pressure gas refrigerant pipe and the high-pressure gas refrigerant pipe are closed. Thereby, it is possible to recover the refrigerant in the multi-branch selector 200 to the heat source-side unit side.

[0096] Instead of controlling the valves in the heat source-side unit, the safety measure section 652 can control the liquid shut-off valve 264, the expansion mechanism 263, and the high-pressure gas control valve 262 to be closed and the gas shut-off valve 265 and the low-pressure gas control valve 261 to be opened before the operation of the refrigerant compressor. After the predetermined condition as described above is satisfied, the safety measure section 652 can control the gas shut-off valve 265 and the low-pressure gas control valve 261 to be closed.

[0097] The safety measure section 652 can be further configured to control the corresponding liquid shut-off valve 264 and gas shut-off valve 265 (see FIG. 6) to be closed via the unit control section 630 upon being notified from the leakage judgment section 651 that a refrigerant leakage has occurred in the utilization-side pipe section or the utilization-side pipe section. The safety measure section 652 can further be configured to control the air discharge mechanism 500 to be operated via the unit control section 630. Figure 1 ) control to be closed. The safety measure section 652 can further be configured to output an alarm information and / or an alarm signal indicating that a refrigerant leakage has occurred in the utilization-side pipe section.

[0098] The safety measure section 652 does not cause the operation of the air discharge mechanism 500 to start unless it has been judged that a refrigerant leakage has occurred. However, the safety measure section 652 can do so when receiving an instruction from a monitoring / maintenance person via a user interface (not shown) of the valve unit 100 such as a key switch, a touch panel, or the like, or receiving an instruction from an external device through a signal. The signal is generated and transmitted by the heat source-side unit and transmitted through wired / wireless communication.

[0099] According to the controller 600 having the above-described configuration, it is possible to judge whether a refrigerant leakage has occurred during the non-operation of the air discharge mechanism 500. When the air discharge mechanism 500 is not operated, the internal space 301 of the casing 300 is substantially closed due to the partitioning body. Therefore, when a refrigerant leakage has occurred in the multi-branch selector 200, the leaked refrigerant accumulates in the internal space 301, and thus it is possible to quickly detect the occurrence of the refrigerant leakage. Furthermore, when it is detected that a refrigerant leakage has occurred, it is possible to reduce the concentration of the leaked refrigerant in the internal space 301 by operating the air discharge mechanism 500.

[0100] The controller 600 can be divided into a first controller having a function of controlling the multiple branch selector 200 and a second controller having a function of controlling the air discharge mechanism 500, the liquid stop valve 264, and the gas stop valve 265. With this configuration, it is preferable that the first controller and the second controller have different power sources.

[0101] Operation of the controller

[0102] Figure 3 is a flowchart showing steps performed by the controller 600.

[0103] In step S1100, the leakage judging section 651 acquires the sensor detection value Vs from the semiconductor gas sensor 400 via the detection value acquiring section 620.

[0104] In step S1200, the leakage judging section 651 compares the sensor detection value Vs and the detection value threshold Vth, and judges whether the sensor detection value Vs is less than the detection value threshold Vth. The detection value acquiring section 620 or the leakage judging section 651 can obtain a moving average of the sensor detection value Vs over a certain length of time, and use this moving average as the sensor detection value Vs to compare with the detection value threshold Vth in step S1200. If the sensor detection value Vs is less than the detection value threshold Vth (S1200: Yes), the leakage judging section 651 proceeds to step S1300 as described later, and if the sensor detection value Vs is equal to or greater than the detection value threshold Vth (S1200: No), it proceeds to step S1400.

[0105] In step S1300, the leakage detecting section 650 judges whether termination of the operation has been specified. This specification can be made by a user operation, another device, or the leakage detecting section 650 itself. If termination of the operation has not been specified (S1300: No), the leakage detecting section 650 returns to step S1100, and if it has been specified (S1300: Yes), it terminates its operation.

[0106] In step S1400, the safety measure section 652 causes the operation of the fan 510 to start via the unit control section 630, and outputs an alarm information via the information output section 640. In the case where the check damper 520 is an electrically controlled damper, the safety measure section 652 also controls the check damper 520 to be opened.

[0107] By the above steps, the controller 600 can correctly and promptly detect the refrigerant leakage and reduce the concentration of the leaked refrigerant in the internal space 301 of the casing 300. More specifically, it is possible to prevent the refrigerant concentration in the internal space 301 from exceeding the detection value threshold Vth. It is preferable that the detection value threshold Vth is set to a value smaller than a value corresponding to 25% of the lower flammable limit (LFL) of the refrigerant used.

[0108] Advantageous Effects

[0109] As described above, the valve unit 100 according to the present embodiment has the casing 300 for accommodating the multi-branch selector 200 and the air discharge mechanism 500 configured to discharge air in the internal space of the casing 300 to the external space of the casing 300 when the refrigerant leakage occurs. Thereby, when the refrigerant leakage occurs in the multi-branch selector 200, the refrigerant leakage can be quickly detected and the concentration of the leaked refrigerant in the space where the multi-branch selector 200 is disposed can be reduced. Therefore, the monitoring / maintenance personnel can safely check the state of the multi-branch selector 200 and / or repair the multi-branch selector 200 as needed, so that the maintainability and safety of the air conditioning system can be improved.

[0110] Variations

[0111] The configuration and steps of the valve unit 100 as described above can be changed according to circumstances.

[0112] For example, the casing 200 can further include a pressure release valve. The pressure release valve can be disposed in a bypass pipe (not shown) that branches from the respective utilization-side liquid pipe portion 211 at a position point between the respective pipe hole 310 of the casing 300 and the respective shutoff valve 264, and merges with the low-pressure gas pipe portion 220. The bypass pipe can be connected separately from the low-pressure gas pipe portion 220, or merged with a common pipe leading to the low-pressure gas pipe portion 220. Therefore, even when the respective liquid shutoff valve 264 and gas shutoff valve 265 are closed, it is possible to release the pressure from the utilization-side piping section to prevent the utilization-side piping section from causing liquid seal.

[0113] The liquid shutoff valves 264 can be further provided in the heat-source-side liquid pipe portion 210, and the gas shutoff valves 265 can be further provided in each of the low-pressure gas pipe portion 220 and the high-pressure gas pipe portion 240. In this case, when a refrigerant leakage occurs in the casing 300, the controller 600 can control all of the liquid shutoff valves 264 and the gas shutoff valves 265 to be closed. Thereby, when a refrigerant leakage occurs in the casing 300, it is possible to prevent the refrigerant from further flowing into the multi-branch selector 200. It is also preferable that the controller 600 be configured to close the liquid shutoff valves 264 and the gas shutoff valves 265 when a power failure occurs in the valve unit 100. In this case, the controller 600 can include a capacitor that can store electric power, and be configured to release the electric power by discharging the capacitor to close the liquid shutoff valves 264 and the gas shutoff valves 265 when the power failure occurs.

[0114] The air discharge mechanism 500 does not necessarily need the fan 510 and the check damper 520. For example, if ventilation of the internal air can be achieved by merely opening one or more openings formed in the casing 300 and normally closed, the air discharge mechanism 500 can be a mechanism configured to control the opening / closing state of the openings, such as an electrically controlled check damper. Natural convection or air flow caused by an external mechanism can be used for such ventilation.

[0115] Another fan configured to blow air toward the internal space can be provided instead of or in addition to the above-described check damper 520. In this case, it is preferable that the capacity of the additional fan be determined so that the air pressure in the internal space 301 remains lower than the air pressure in the space around the casing 300 in combination with the capacity of the fan 510.

[0116] If the refrigerant used is heavier than air and thus allows a gap or an opening to be formed in the upper portion of the casing 300, the check damper 520 is not necessarily needed. If the isolation of the internal space 301 of the casing 300 is sufficient without any particular isolator, such an isolator can be omitted. However, in this case, at least one opening for discharging the internal air and another opening for mitigating the air discharge should be formed in the casing 300.

[0117] The casing 300 can accommodate not the multi-branch selector 200 but another type of unit having at least one liquid refrigerant pipe portion, at least one gas refrigerant pipe portion, at least one liquid control valve provided in the liquid refrigerant pipe portion, and at least one gas control valve provided in the gas refrigerant pipe portion. Each of the liquid control valve and the gas control valve can be any type of valve for controlling the flow rate of the refrigerant in the corresponding pipe portion.

[0118] For example, such as Figure 4 As shown, valve unit 100a can be applied to heat pump systems with a so-called dual-pipe configuration. (And...) Figure 1 Compared to the configuration shown, the valve unit 100a, a variant of this embodiment, does not include the high-pressure gas piping section 240, the low-pressure gas sub-piping 221, the high-pressure gas sub-piping 241, the bypass piping 251, the refrigerant heat exchanger 252, the low-pressure gas control valve 261, the high-pressure gas control valve 262, and the expansion mechanism 263. Alternatively, the valve unit may have a configuration for use with only a single user-side unit.

[0119] When a valve closing command is received, the safety measure unit 652 can close the liquid shut-off valve 264 and the gas shut-off valve 265 via the unit control unit 630. This occurs, for example, when monitoring / maintenance personnel begin maintenance or repair of the utilization-side piping section. The leak detection unit 650 can receive reset commands from monitoring / maintenance personnel via a signal through a user interface or from an external device. If a reset command has been issued, the leak detection unit 650 can open the liquid shut-off valve 264 and the gas shut-off valve 265.

[0120] All or part of the controller 600 may be detached from the valve unit 100. In this case, the valve unit 100 should have a communication interface so that the controller 600 can acquire the sensor detection value Vs of the sensor 400 and control the operation of the mechanical equipment of the valve unit 100, including the air emission mechanism 500.

[0121] If internal air is continuously or periodically vented under the control of controller 600, refrigerant leak detection is not necessarily required, and therefore sensor 400 is not needed. In this case, it is not necessary to... Figure 3 The steps are shown.

[0122] Although only selected embodiments of the invention have been described, it will be apparent to those skilled in the art from this disclosure that various changes and modifications can be made without departing from the scope of the disclosure as defined by the appended claims. For example, unless otherwise specifically stated, the size, shape, position, or orientation of various components may be varied as needed and / or desired, provided that such changes do not substantially affect their intended function. Unless otherwise specifically stated, components shown as directly connected or in contact with each other may have intermediate structures configured between them, provided that such variations do not materially affect their intended function. Unless otherwise specifically stated, the function of one element may be performed by two elements, and vice versa. The structure and function of one embodiment may be employed in another embodiment. All advantages need not occur simultaneously in a particular embodiment. Therefore, the foregoing description provided according to embodiments of the invention is for illustrative purposes only.

[0123] [LIST OF REFERENCE NUMERALS]

[0124] 100, 100a: valve unit

[0125] 200: multiple branch selector

[0126] 210: heat-source-side liquid pipe portion (liquid refrigerant pipe portion)

[0127] 211: utilization-side liquid pipe portion (liquid refrigerant pipe portion)

[0128] 220: low-pressure gas pipe portion (gas refrigerant pipe portion, heat-source-side gas pipe portion)

[0129] 221: low-pressure gas sub-pipe (gas refrigerant pipe portion)

[0130] 230: utilization-side gas pipe portion (gas refrigerant pipe portion)

[0131] 240: high-pressure gas pipe portion (gas refrigerant pipe portion, heat-source-side gas pipe portion)

[0132] 241: high-pressure gas sub-pipe (gas refrigerant pipe portion)

[0133] 251: bypass pipe

[0134] 252: refrigerant heat exchanger

[0135] 261: low-pressure gas control valve (gas control valve)

[0136] 262: high-pressure gas control valve (gas control valve)

[0137] 263: expansion mechanism

[0138] 264: liquid shutoff valve (liquid control valve)

[0139] 265: gas shutoff valve (gas control valve)

[0140] 270: pipe connecting member

[0141] 300: housing

[0142] 301: internal space

[0143] 310: pipe hole

[0144] 320: discharge opening

[0145] 330: intake opening

[0146] 340: partition

[0147] 400: sensor;

[0148] 500: air discharge mechanism;

[0149] 510: fan;

[0150] 511: air duct;

[0151] 520: non-return damper;

[0152] 600: controller;

[0153] 610: storage section;

[0154] 620: detected value acquisition section;

[0155] 630: unit control section;

[0156] 640: information output section;

[0157] 650: leakage detection section;

[0158] 651: leakage determination section;

[0159] 652: safety measure section.

[0160] Bibliographic references

[0161] Patent literature

[0162] [Patent literature 1] EP 30911314 A1.

Claims

1. A valve unit for use in a heat pump system, comprising: At least one liquid refrigerant piping section; At least one gas refrigerant piping section; At least one liquid control valve is configured in the liquid refrigerant piping section; At least one gas control valve is configured in the gas refrigerant piping section; A housing that at least accommodates the liquid control valve and the gas control valve; A sensor configured to detect the concentration of the refrigerant in the air within the housing; Air emission control system; as well as A controller is configured to determine that a refrigerant leak has occurred in the housing when the detected concentration is equal to or greater than a detection threshold, and to control the air venting mechanism to start operating when the refrigerant leak occurs. The air emission mechanism includes: A fan configured to draw air from the interior space of the housing toward the exterior space of the housing; and A backflow preventer allows air to flow from the outside of the housing through an opening in the housing to the interior space when the fan draws in the air. The air venting mechanism is configured to operate by activating the fan and keeping the check damper open in the event of a refrigerant leak within the housing, thereby releasing air from the interior space of the housing to the external space outside the housing. The suction port or discharge port of the fan is connected to the discharge opening of the housing via an air duct, or the fan is mounted on the housing at the discharge opening such that the suction port of the fan faces the interior space of the housing and the discharge port of the fan faces the exterior of the housing.

2. The valve unit as described in claim 1, characterized in that, The liquid refrigerant piping section and the gaseous refrigerant piping section are respectively formed as a portion of the liquid refrigerant piping and a portion of the gaseous refrigerant piping extending between the heat source-side heat exchanger and the utilization-side heat exchanger of the heat pump system, and The controller is also configured to close the liquid control valve and the gas control valve in the event of a refrigerant leak in the utilization side piping section. The utilization-side piping section extends between the liquid control valve and the gas control valve, and includes at least the utilization-side heat exchanger.

3. The valve unit as described in claim 1 or 2, characterized in that, The valve unit includes the backflow preventer, wherein... The backflow preventer (520) is configured to be operated by an electric motor, and The controller is configured to control the motor to open the check damper when a refrigerant leak occurs in the housing.

4. The valve unit as described in claim 2, characterized in that, The controller is further configured to output an alarm message when a refrigerant leak occurs in the housing or in the utilization-side piping section.

5. The valve unit as claimed in any one of claims 1, 2, and 4, characterized in that, The at least one gaseous refrigerant piping section includes: Low-pressure gas piping section; High-pressure gas piping section; and The side-mounted gas piping section is divided into a low-pressure gas piping section and a high-pressure gas piping section. The at least one liquid control valve includes: A liquid shut-off valve is configured in the liquid refrigerant piping section, and The at least one gas control valve includes: A low-pressure gas control valve configured in the low-pressure gas piping section; The high-pressure gas control valve configured in the high-pressure gas piping section; and A gas shut-off valve is installed in the gas piping section on the utilization side.

6. The valve unit as claimed in any one of claims 1, 2, and 4, characterized in that, The at least one liquid refrigerant piping section includes: Multiple side-mounted liquid piping sections; and The heat source-side liquid piping section is further branched into the utilization-side liquid piping section. The at least one gaseous refrigerant piping section includes: Multiple gas piping sections utilizing the side; and The heat source-side gas piping section, which branches out to the utilization-side gas piping section. The at least one liquid control valve includes a plurality of liquid shut-off valves respectively disposed in the liquid piping section on the utilization side. The at least one gas control valve includes a plurality of gas shut-off valves respectively disposed in the gas piping section on the utilization side.

7. The valve unit as claimed in any one of claims 1, 2, and 4, characterized in that, The at least one liquid refrigerant piping section includes: Multiple side-mounted liquid piping sections; and The heat source-side liquid piping section is further branched into the utilization-side liquid piping section. The at least one gaseous refrigerant piping section includes: Multiple low-pressure gas sub-pipelines; The branch is the low-pressure gas piping section of the aforementioned low-pressure gas sub-pipeline; Multiple high-pressure gas sub-pipelines; The branch is the high-pressure gas piping section of the high-pressure gas sub-pipe; and Multiple utilization-side gas piping sections, each branching into one of the low-pressure gas sub-pipes and one of the high-pressure gas sub-pipes, are connected to the low-pressure gas piping section and the high-pressure gas piping section respectively via the low-pressure gas sub-pipe and the high-pressure gas sub-pipe. The at least one liquid control valve includes a plurality of liquid shut-off valves respectively disposed in the liquid piping section on the utilization side, and The at least one gas control valve includes: Multiple low-pressure gas control valves are respectively configured in the low-pressure gas sub-pipeline; Multiple high-pressure gas control valves respectively configured in the high-pressure gas sub-pipeline; and Multiple gas shut-off valves are respectively configured in the gas piping section on the utilization side.

8. The valve unit as claimed in any one of claims 1, 2, and 4, characterized in that, It also includes an isolator applied to the housing to isolate the interior space of the housing from the external space surrounding the housing, at least when the air exhaust mechanism is not in operation.

9. The valve unit as described in claim 5, characterized in that, The valve unit includes the low-pressure gas control valve and the high-pressure gas control valve, wherein... A microchannel is formed in at least one of the low-pressure gas control valve and the high-pressure gas control valve. The microchannel is configured and arranged to allow refrigerant to flow through the microchannel even when the opening of at least one of the low-pressure gas control valve and the high-pressure gas control valve is set to the minimum opening.

10. The valve unit as claimed in any one of claims 1, 2, and 4, characterized in that, The refrigerant is R32 refrigerant.

11. A method for assembling a valve unit as claimed in any one of claims 1 to 10, wherein, The housing is composed of multiple housing components, and the method includes: The housing component is disposed around at least the liquid control valve and the gas control valve; and The housing components are secured to each other.

12. The method as described in claim 11, characterized in that, Also includes The air emission mechanism is attached to the housing.

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