Air conditioners

Abstract

The air conditioner 1 according to an embodiment comprises: an outdoor unit 2; an indoor unit 3 connected to the outdoor unit 2 by refrigerant piping; a shutoff unit 4 capable of shutting off the flow of refrigerant in the refrigerant piping between the outdoor unit 2 and the indoor unit 3; and a refrigerant leak detector 30a that detects a refrigerant leak. The shutoff unit 4 is provided with a shutoff valve 41 that shuts off the flow of the refrigerant in the refrigerant piping, and a valve control unit 42 serving as a control unit that controls the operation of the shutoff valve 41. The shutoff valve 41 is an electric valve driven by a motor. If a refrigerant leak is detected by the refrigerant leak detector 30a, the valve control unit 42 controls the shutoff valve 41 to be closed at an operation speed (v1), and then controls the shutoff valve 41 to be retightened at an operation speed (v2) slower than the operation speed (v1).

Description

[Technical field]

[0001] An embodiment of the present invention relates to an air conditioner. [Background technology]

[0002] Conventionally, some air conditioners that use flammable refrigerants, including those that are slightly flammable, are equipped with a shutoff valve for safety purposes to shut off the flow of refrigerant to an indoor unit in which a leak has occurred when a refrigerant leak is detected by a gas sensor that detects the refrigerant. For example, Patent Document 1 discloses an air conditioner that is equipped with a shutoff valve consisting of a solenoid valve in the refrigerant piping that connects the indoor unit and the outdoor unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-134005 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, if the operating speed of the shutoff valve is slow, the refrigerant cannot be shut off quickly, so it is desirable to operate the shutoff valve as quickly as possible. However, if a shut-off valve driven by a motor is operated at high speed, the driving torque of the motor becomes small, causing a mismatch between the driving output to the motor and the opening of the shut-off valve, making it impossible to operate the shut-off valve accurately and potentially preventing it from being completely closed.

[0005] Therefore, an air conditioner capable of shutting off the refrigerant as quickly and reliably as possible is provided. [Means for solving the problem]

[0006] An air conditioner according to an embodiment includes an outdoor unit, an indoor unit connected to the outdoor unit through a refrigerant pipe, a shutoff unit capable of shutting off the flow of refrigerant in the refrigerant pipe between the outdoor unit and the indoor unit, and a refrigerant leakage detection unit that detects refrigerant leakage. The shutoff unit includes a shutoff valve that shuts off the flow of refrigerant in the refrigerant pipe, and a control unit that controls the operation of the shutoff valve. The shutoff valve is an electric valve driven by a motor, and when a refrigerant leakage is detected by the refrigerant leakage detection unit, the control unit controls the shutoff valve to close at an operating speed (v1), and then controls the shutoff valve to be tightened at an operating speed (v2) slower than the operating speed (v1). [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram illustrating an example of a schematic configuration of an air conditioner according to an embodiment. [Diagram 2] FIG. 2 is a diagram showing a schematic example of the electrical configuration of an air conditioner; [Diagram 3] FIG. 2 is a schematic cross-sectional view of an example of the configuration of a motor-operated valve; [Figure 4] Control flow chart of the valve control unit [Diagram 5] Control flow chart of the indoor control unit and the refrigerant leakage detection unit [Figure 6] FIG. 1 is a diagram showing a schematic configuration example of another air conditioner; [Figure 7] FIG. 1 is a schematic cross-sectional view of an example of the configuration of another motor-operated valve; [Figure 8] FIG. 13 is a diagram showing a schematic diagram of another example of the electrical configuration of an air conditioner; [Figure 9] Control flow chart of the indoor control unit and the refrigerant leakage detection unit DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment will be described. As shown in FIG. 1, the air conditioner 1 of this embodiment has a so-called multi-type configuration, and one outdoor unit 2, for example, three indoor units 3A, 3B, and 3C are connected by a first pipe 6 and a second pipe 7 as refrigerant pipes through which a refrigerant flows. A flammable refrigerant, for example, a slightly flammable refrigerant such as HFC-R32, is filled in the refrigeration cycle connected by the first pipe 6 and the second pipe 7. Furthermore, the air conditioner 1 is equipped with a shutoff unit 4 capable of shutting off the flow of refrigerant between the outdoor unit 2 and the indoor unit 3, and a power storage unit 5. The power storage unit 5 is preferably a rechargeable lithium ion battery, but is not limited to this, and may be a large-capacity capacitor. Hereinafter, when a description common to each indoor unit 3 is given, it will be simply referred to as the indoor unit 3 without adding A, B, or C. In addition, in FIG. 1, the power supply paths from an external power source 8 to the outdoor unit 2, the indoor unit 3, and the circuit breaker unit 4 are shown typically with relatively thick solid lines, and the power supply paths from the storage unit 5 to the circuit breaker unit 4 are shown typically with relatively thick dashed lines.

[0009] The outdoor unit 2 and each indoor unit 3 are connected by a first pipe 6 corresponding to a refrigerant pipe through which mainly liquid refrigerant flows, and a second pipe 7 corresponding to a gas refrigerant pipe through which mainly gas refrigerant flows. The first pipe 6 and the second pipe 7 correspond to a refrigerant piping system connecting the outdoor unit 2 and the indoor unit 3. The outdoor unit 2 includes an outdoor heat exchanger 21, an outdoor expansion valve 22, an outdoor blower 23, a four-way valve 24, and a compressor 25. However, the configuration of the outdoor unit 2 shown in FIG. 1 is an example, and the outdoor unit 2 may include, for example, an accumulator, a pressure sensor, and the like. The number of indoor units 3 may be one or more, and a plurality of outdoor units 2 may be connected in parallel on a refrigeration cycle.

[0010] The indoor unit 3 includes an indoor control unit 30, an indoor heat exchanger 31, an indoor expansion valve 32 provided on the first piping 6 side of the indoor heat exchanger 31, and an indoor blower 33. The indoor control unit 30 is configured with a microcomputer (not shown), and controls the operation of the indoor unit 3, such as starting and stopping operation, and the associated operation of the indoor expansion valve 32 and indoor blower 33. This indoor control unit 30 is connected to an operation panel (not shown), a so-called remote control device, that inputs operations to start and stop operation and sets and displays the temperature of the air-conditioned space 100, and controls the air conditioner 1 in response to its instructions.

[0011] Also, as shown in Fig. 2, a refrigerant leakage detection unit 30a is connected to the indoor control unit 30. This refrigerant leakage detection unit 30a is equipped with a gas sensor 9 that detects flammable refrigerant in the air, and when a signal indicating that a refrigerant has been detected is input from the gas sensor 9, the refrigerant leakage detection unit 30a determines that a refrigerant leak has occurred near the indoor unit 3. Also, a buzzer 60 serving as a sound output unit is connected to the refrigerant leakage detection unit 30a, and the refrigerant leakage detection unit 30a sounds the buzzer 60 when it detects a refrigerant leak as described below. This buzzer 60 can also be provided in the indoor control unit 30, as will be described later in Fig. 8.

[0012] In this embodiment, the gas sensor 9 is provided in the indoor unit 3, but the gas sensor 9 can also be installed in the air conditioned space 100, for example at a low position within the air conditioned space 100, in order to detect refrigerant that is generally considered to be heavier than air. In that case, the indoor control unit 30 and the refrigerant leakage detection unit 30a can be connected by a signal cable or the like.

[0013] 1, in this embodiment, three indoor units, 3A, 3B, and 3C, are connected in parallel to a single refrigerant piping system. Furthermore, in this embodiment, it is assumed that the three indoor units 3A to 3C air-condition the air-conditioned spaces 100a to 100c, respectively.

[0014] The outdoor unit 2, indoor unit 3, and refrigerant piping system constitute a refrigeration cycle for conditioning the air-conditioned space 100. However, the configuration of the refrigeration cycle shown in Fig. 1, the number of indoor units 3 connected to the refrigerant piping system, the number of air-conditioned spaces 100, or the number of indoor units 3 installed in the air-conditioned space 100 are merely examples and are not limited to these. For example, one air-conditioned space 100 may be configured to be air-conditioned by multiple indoor units 3.

[0015] During cooling operation, the air conditioner 1 supplies the refrigerant discharged from the compressor 25 to the indoor unit 3 via the outdoor heat exchanger 21, the outdoor expansion valve 22 and the first piping 6, as indicated by the solid arrow C, and switches the four-way valve 24 so that the refrigerant flowing out of the indoor unit 3 returns to the compressor 25 via the second piping 7.

[0016] On the other hand, during heating operation, the air conditioner 1 supplies the refrigerant discharged from the compressor 25 to the indoor unit 3 via the second piping 7, as indicated by dashed arrow H, and switches the four-way valve 24 so that the refrigerant flowing out of the indoor unit 3 returns to the outdoor heat exchanger 21 via the indoor expansion valve 32, the first piping 6, and the outdoor expansion valve 22. The switching of the four-way valve 24 and the operation of the compressor 25 are controlled by an outdoor control device (not shown) that controls the refrigeration cycle in response to instructions from each indoor control unit 30.

[0017] The shutoff unit 4 is composed of a plurality of shutoff valves 41 capable of shutting off the flow of refrigerant between the outdoor unit 2 and the indoor unit 3, and a valve control unit 42 that controls the operation of the shutoff valves 41. The shutoff valves 41 are so-called motor-operated valves driven by a motor, and the opening degree can be adjusted. Such motor-operated valves are also called PMVs (Pulse Motor Valves).

[0018] The shutoff valves 41 are provided on the first piping 6 side and the second piping 7 side of each indoor unit 3. Specifically, a shutoff valve 41A1 is provided between the indoor expansion valve 32A and the outdoor expansion valve 22 on the first piping 6 side of the indoor unit 3A, and a shutoff valve 41A2 is provided between the indoor heat exchanger 31A and the four-way valve 24 on the second piping 7 side.

[0019] Similarly, a shutoff valve 41B1 is provided between the indoor expansion valve 32B and the outdoor expansion valve 22 on the first piping 6 side of the indoor unit 3B, and a shutoff valve 41B2 is provided between the indoor heat exchanger 31B and the four-way valve 24 on the second piping 7 side. Also, a shutoff valve 41C1 is provided between the indoor expansion valve 32C and the outdoor expansion valve 22 on the first piping 6 side of the indoor unit 3C, and a shutoff valve 41C2 is provided between the indoor heat exchanger 31C and the four-way valve 24 on the second piping 7 side. In a so-called simultaneous cooling and heating multi-air conditioner in which each of the multiple indoor units 3 can freely select cooling or heating, each indoor unit 3 is connected to the outdoor unit 2 by three refrigerant pipes, so in this case, three shutoff valves 41 are required for each indoor unit 3, the same as the number of refrigerant pipes.

[0020] The air conditioner 1 can block the flow of refrigerant between the first pipe 6 and the indoor unit 3, and between the second pipe 7 and the indoor unit 3, by closing these shutoff valves 41. This allows the corresponding indoor unit 3 to be isolated from the refrigeration cycle. In the following, when describing all the shutoff valves 41 in common, they will be simply referred to as shutoff valves 41 without the designation A1 or the like. The operation of these shutoff valves 41 is controlled by a valve control unit 42.

[0021] The valve control unit 42 is configured with a microcomputer or the like (not shown), and executes processing to control the operation of the shutoff valve 41. In the case of this embodiment, the valve control unit 42 controls the operation of each shutoff valve 41 provided in each indoor unit 3. That is, in this embodiment, a common shutoff unit 4 is provided for multiple indoor units 3 connected in parallel to a single refrigerant piping system, and the operation of each shutoff valve 41 provided corresponding to each indoor unit 3 is centrally controlled by the common valve control unit 42 as shown in FIG.

[0022] The arrangement of the indoor units 3 varies depending on the structure of the building, and the indoor units 3 may be installed at a distance from each other. For this reason, a valve control unit 42 corresponding to each indoor unit 3 may be provided, or a valve control unit 42 that centrally controls several indoor units 3 may be combined with a valve control unit 42 that individually controls each indoor unit 3. The portion in FIG. 2 excluding the external power source 8 and the indoor units 3 constitutes the shutoff unit 4. The valve control unit 42 is connected to the indoor control unit 30 by a communication line 42c, enabling mutual signal exchange. The indoor control unit 30 issues a refrigerant leakage detection signal (described later) and an instruction to open a blocked shutoff valve 41 to the valve control unit 42.

[0023] This valve control unit 42 includes a power interruption detection unit 42a that detects interruption of the supply of power from the external power source 8. The power interruption detection unit 42a is realized by combining a voltage detector for the external power source 8 and software generated by executing a program in the valve control unit 42. However, the power interruption detection unit 42a may also be configured to be realized entirely by hardware.

[0024] The power interruption detection unit 42a monitors the supply of power from the external power source 8, and when power supply from the external power source 8 is no longer provided, determines that the supply of power from the external power source 8 has been interrupted. Hereinafter, this state will be referred to as a power interruption. Note that a power interruption is expected to occur due to, for example, a power outage, damage to the power supply path, erroneous tripping of a breaker, or the like.

[0025] The power storage unit 5 is connected to the valve control unit 42 via a signal line 42b, and supplies power to the cutoff unit 4 when the external power source 8 is cut off due to a power outage or the like. Specifically, the power storage unit 5 is always charged with power supplied from the external power source 8 and stores power while power is being supplied from the external power source 8, and supplies the stored power to the valve control unit 42 and the cutoff valve 41 of the cutoff unit 4 based on a start command from the valve control unit 42 output via the signal line 42b when a power cutoff is detected. For this reason, the cutoff unit 4 is configured so that the valve control unit 42 and the cutoff valve 41 can be operated even when the power is cut off. In this case, in order to make the valve control unit 42 operable during the period until the external power source 8 is cut off and the supply of power from the power storage unit 5 is started, a backup power circuit (not shown), such as a large-capacity capacitor, can be provided, or a configuration can be used in which power is always supplied from the power storage unit 5 to the valve control unit 42, and when the external power source 8 is cut off, the supply of power to the cutoff valve 41 is switched to the power storage unit 5 side.

[0026] Although Figure 1 shows an example of a configuration in which one power storage unit 5 is provided for the shutoff unit 4, it is also possible to provide a configuration in which a plurality of power storage units 5 are provided for the air conditioner 1, such as providing one power storage unit 5 for each shutoff valve 41, or providing one power storage unit 5 for each indoor unit 3 as shown in Figure 5 described later.

[0027] Here, the shutoff valve 41 will be described in detail. The shutoff valve 41 is an electric valve also called a pulse motor valve, which is controlled to open and close by the rotation of a motor, unlike a solenoid type so-called electromagnetic valve. For this reason, the shutoff valve 41 has a slower operating speed when closing a flow path compared to a general solenoid valve. This is due to the structure of the shutoff valve 41, as described below. Note that the operating speed here technically means the time required to close an open flow path, or the time required to open a closed flow path. For example, the shorter the time required to close a flow path, the faster the operating speed, and the longer the time required to close a flow path, the slower the operating speed.

[0028] 3, the shutoff valve 41 includes a valve body 41c having a first connection end 41a serving as an inlet or outlet for the refrigerant, and a second connection end 41b serving as an inlet or outlet for the refrigerant. When the first connection end 41a serves as the inlet for the refrigerant, the second connection end 41b serves as the outlet for the refrigerant, and when the first connection end 41a serves as the outlet for the refrigerant, the second connection end 41b serves as the inlet for the refrigerant.

[0029] The valve body 41c is hollow and has a valve seat 41d, which is a cylindrical opening connected to the second connection end 41b. The valve body 41c is arranged coaxially with the valve seat 41d and accommodates a valve rod 41e that is movable relative to the valve body 41c in the vertical direction in the figure. The valve rod 41e has a male thread on the surface of the tip side, which is the lower side in the figure, and is passed through a bearing part 41f that is fixed to the valve body 41c and has a female thread at the part through which the valve rod 41e passes.

[0030] The valve rod 41e is fixed at its upper end to a rotor 41h of a pulse motor 41g. The rotor 41h is a rotor having multiple magnetic poles, and is rotatable coaxially with the valve rod 41e and is slidable in the vertical direction relative to the case body 41i.

[0031] The upper end of the case body 41i is closed by a cover member 41j. The case body 41i is located on the outer periphery of the range in which the rotor 41h can slide, and a stator 41k of the pulse motor 41g is provided. The stator 41k is formed of a coil 41l as is well known, and a lead wire 41m connected to the valve control unit 42 side is led out from the coil 41l as shown in FIG.

[0032] In the shutoff valve 41 having such a configuration, when a control signal is input from the valve control unit 42, a predetermined current pulse is output to the pulse motor 41g, which causes the rotor 41h having magnetic poles to rotate together with the valve stem 41e, and since the male threaded portion in the middle of the valve stem 41e is inserted into the female threaded portion of the bearing portion 41f, the valve stem 41e moves in the vertical direction in the figure as it rotates. Note that in Fig. 2, for the sake of simplicity, a drive circuit for driving the pulse motor 41g, which is composed of, for example, a transistor bridge, is not shown.

[0033] At this time, the valve rod 41e is arranged in a position coaxial with the valve seat 41d, and the tip of the valve rod 41e, which is on the lower side in the figure, is formed, for example, in a wedge shape so as to be insertable into and removable from the valve seat 41d. When the tip of the valve rod 41e is inserted into the valve seat 41d and the valve seat 41d is blocked by the valve rod 41e, the refrigerant flow path between the first connection end 41a and the second connection end 41b is blocked. This state corresponds to a state in which the shutoff valve 41 is closed. Hereinafter, the position of the valve rod 41e when the shutoff valve 41 is closed is referred to as the closed position.

[0034] On the other hand, when a gap is generated between the valve rod 41e and the valve seat 41d, the flow path of the refrigerant between the first connection end 41a and the second connection end 41b is at least partially open. This state is the open state of the shutoff valve 41. At this time, the flow rate of the refrigerant can be adjusted by changing the position of the valve rod 41e.

[0035] For example, when the valve stem 41e is pulled slightly upward from the closed position in the figure, a small refrigerant flow path is formed at the valve seat 41d. This flow path becomes larger as the valve stem 41e is pulled upward in the figure, and is maximized when the valve stem 41e is completely pulled out from the valve seat 41d. In this way, the opening degree of the shutoff valve 41 can be adjusted by the position of the valve stem 41e. Hereinafter, the position of the valve stem 41e pulled up to the upper limit on the upper side in the figure is referred to as the open position.

[0036] Next, the operation of the above-described air conditioner 1 will be described. The air conditioner 1 is equipped with a shutoff valve 41 capable of shutting off the flow of refrigerant in the refrigerant piping system. Therefore, for example, when a refrigerant leak into the air-conditioned space 100 is detected, it becomes possible to shut off the flow of refrigerant flowing into the indoor unit 3 and the flow of refrigerant flowing out of the indoor unit 3. This is thought to suppress further refrigerant leakage and ensure safety within the air-conditioned space 100.

[0037] Incidentally, the air conditioner 1 needs to operate the shutoff valve 41 to shut off the flow of refrigerant not only when a refrigerant leak is detected, but also when the supply of power from the external power source 8 is cut off. For this reason, the air conditioner 1 is provided with a power storage unit 5, which makes it possible to operate the valve control unit 42 and shutoff valve 41 to shut off the flow of refrigerant for a certain amount of time when the external power source 8 is cut off.

[0038] When the shutoff valve 41 is closed, if the operating speed of the shutoff valve 41 is slow, the refrigerant may not be shut off quickly. Therefore, it is desirable to operate the shutoff valve 41 as fast as possible. On the other hand, in the case of the shutoff valve 41 that is driven to open and close using a motor, the power consumption increases when the motor is driven at high speed. As a result, when the supply of power from the external power source 8 is cut off and the shutoff valve 41 is operated using the power of the power storage unit 5, the charging power of the power storage unit 5 is rapidly reduced due to the power consumption when the motor is driven. For this reason, if the shutoff valve 41 is closed repeatedly in a short period of time, the charge amount of the power storage unit 5 decreases, and there is a risk that the shutoff valve cannot be operated.

[0039] Furthermore, when the shutoff valve 41 driven by the motor is operated at high speed, the drive torque of the motor becomes small, and the shutoff valve 41 cannot be operated accurately and may not be completely closed. Also, when the pulse output speed of the pulse signal output from the valve control unit 42 is fast, even if a signal with the required number of pulses is output from the valve control unit 42, the rotation of the rotor 41h cannot respond, so-called pulse drop occurs, and the shutoff valve 41 may not operate to the closed position.

[0040] Therefore, in the air conditioner 1, the valve control unit 42 executes the process shown in the flowchart of Fig. 4, so that the refrigerant can be shut off quickly and reliably depending on the situation. In simple terms, the air conditioner 1 reduces the risk that the shutoff valve 41 will not be able to operate, and is able to shut off the refrigerant quickly. The process of the valve control unit 42 shown in Fig. 4 includes detection of power shutdown by the power shutdown detection unit 42a. The process of the indoor control unit 30 and the refrigerant leakage detection unit 30a, which are linked to the valve control unit 42, are each shown in Fig. 5.

[0041] 4, the valve control unit 42 determines whether or not a refrigerant leakage signal has been received (S1), and if it determines that a refrigerant leakage signal has not been received (S1: NO), it determines whether or not a power cutoff has been detected (S7). Here, receiving a refrigerant leakage signal means that, as will be described below, the refrigerant leakage detection unit 30a detects a refrigerant leakage into the room and outputs a refrigerant leakage detection signal to the indoor control unit 30, the indoor control unit 30 transmits a refrigerant leakage signal indicating that a refrigerant leakage has been detected to the valve control unit 42 via the communication line 42c, and the valve control unit 42 receives the refrigerant leakage signal.

[0042] Specifically, as shown in the right diagram of Fig. 5, refrigerant leakage detection unit 30a detects refrigerant leakage, and determines whether the concentration of refrigerant gas has exceeded a predetermined value, i.e., whether it has been detected (S11). Note that refrigerant gas refers to gaseous refrigerant sealed in the refrigeration cycle that has leaked from the indoor unit 3 or piping nearby. If refrigerant leakage detection unit 30a has not detected refrigerant gas, i.e., if the concentration of refrigerant gas is extremely low, including 0 (S1: NO), it proceeds to step S11 and continues detecting refrigerant gas.

[0043] In response to this, when the refrigerant leak detection unit 30a detects refrigerant gas (S1: YES), it transmits a refrigerant leak detection signal to the indoor control unit 30 (S12) and sounds an alarm by sounding the buzzer 60 (S13). At this time, in order to stop the refrigerant leak as soon as possible, the refrigerant leak detection unit 30a performs a process of transmitting the refrigerant leak detection signal before the process of sounding the buzzer 60. Note that instead of the buzzer 60 that outputs a predetermined sound when energized, a speaker that outputs a sound corresponding to an input signal can also be used. In other words, the sound output unit can be anything that can output a sound. Furthermore, a light-emitting element such as an LED can be provided so that the alarm can be visually recognized and can be made to emit light in conjunction with the buzzer 60.

[0044] Next, the refrigerant leakage detection unit 30a determines whether a reset operation has been performed or whether a reset signal has been received (S14). This reset operation or reset signal is input or transmitted by a maintenance and inspection worker after the refrigerant leakage has been addressed and eliminated. Therefore, if the reset operation has not been performed or a reset signal has not been received (S14: NO), the refrigerant leakage detection unit 30a repeats this step S14, keeps the buzzer 60 sounding, and waits for the reset operation or the reception of a reset signal.

[0045] On the other hand, if a reset operation is performed or a reset signal is received (S14: YES), the refrigerant leakage detection unit 30a stops sounding the buzzer 60 (S15), returns to the initial state, and determines whether a refrigerant leakage signal has been received again. In this way, when the refrigerant leakage detection unit 30a detects a refrigerant leakage, it sends a refrigerant leakage detection signal once to the indoor control unit 30, and continues sounding the buzzer 60 until the refrigerant leakage is addressed and eliminated, in other words, until safety is confirmed.

[0046] Next, the process of the indoor control unit 30 shown on the right side of Fig. 5 will be described. The indoor control unit 30 judges whether or not a refrigerant leakage detection signal has been received from the refrigerant leakage detection unit 30a (S21). If the indoor control unit 30 has not received a refrigerant leakage detection signal (S21: NO), it executes normal operation processing (S25) and proceeds to step S21 to continue monitoring for reception of a refrigerant leakage detection signal. The normal operation processing includes displaying the temperature in the air-conditioned space 100, accepting operations such as changing settings, and communicating with the outdoor unit 2. On the other hand, if the indoor control unit 30 receives a refrigerant leakage detection signal (S21: YES), it transmits a refrigerant leakage signal to the cutoff unit 4 (S22). This refrigerant leakage signal is a signal for notifying the cutoff unit 4 that a refrigerant leakage has been detected.

[0047] Next, the indoor control unit 30 judges whether an open command has been input (S23). This open command is input, for example, by a user operation or a higher-level control device, after a maintenance worker has dealt with the refrigerant leak, eliminated the refrigerant leak, and confirmed safety. If there is no open command input (S23: NO), the indoor control unit 30 waits, whereas if there is an open command input (S23: YES), it sends an open command to the shutoff unit 4 (S24) and returns. In this way, the indoor control unit 30 and the refrigerant leak detection unit 30a detect the refrigerant, and the detection result is notified to the shutoff unit 4.

[0048] Now, in parallel with these processes being executed by the indoor control unit 30 and the refrigerant leakage detection unit 30a, the shutoff unit 4 performs control to close the shutoff valve 41. Specifically, as shown in FIG. 4, when the valve control unit 42 of the shutoff unit 4 determines that the power supply has not been cut off (S7: NO), it determines whether or not the shutoff valve 41 is closed (S4). When the valve control unit 42 determines that the shutoff valve 41 is closed (S4: YES), it determines whether or not an opening instruction to open the shutoff valve 41 has been issued (S5). Note that YES in step S4 occurs when a refrigerant leakage has already been detected or a power outage has been detected. In addition, the valve control unit 42 stores the previous operation result of either opening or closing the shutoff valve 41, and makes the determination by retrieving the memory.

[0049] The open command is issued by notification from the indoor control unit 30 to the valve control unit 42 via the communication line 42c, in the same way as refrigerant detection. The conditions for sending an open command from the indoor control unit 30 differ between after a refrigerant leak is detected and when restarting operation after power is cut off. That is, when a refrigerant leak is detected, the open command is output only after a maintenance and inspection worker has confirmed the location of the leak and repaired it, and when power is being supplied normally from the external power source 8. Here, the determination that the location of the leak has been confirmed and repaired by a maintenance and inspection worker can be preferably determined based on the condition that a reset operation or a reset signal has been received in the refrigerant leak detection unit 30a (S14: YES).

[0050] On the other hand, when no refrigerant leakage is detected and shutoff valve 41 is closed simply by cutting off the power supply, an instruction to open is output when power is normally supplied from external power supply 8, or when the user issues an instruction to resume operation by operating a remote control device or the like after power is normally supplied from external power supply 8. Therefore, in either case, shutoff valve 41 is changed from closed to open when power is normally supplied from external power supply 8. For this reason, power from power storage unit 5 is not used to drive shutoff valve 41 to open.

[0051] When there is an opening instruction from the indoor control unit 30 via the communication line 42c (S5: YES), the valve control unit 42 opens the shut-off valve 41 (S6). At this time, the valve control unit 42 opens the shut-off valve 41 by outputting X pulses to the pulse motor 41g at a predetermined pulse output speed (v4). As is well known, the pulse output speed is the frequency of the pulse signal when driving the pulse motor 41g and corresponds to the opening and closing operation speed of the shut-off valve 41. Therefore, the higher the pulse output speed, the faster the opening and closing operation speed of the shut-off valve 41, and the lower the pulse output speed, the slower the operation speed of the shut-off valve 41.

[0052] At this time, the pulse output speed (v4) is set slower than the pulse output speed (v1) when closing the shut-off valve 41 when refrigerant leakage is detected. That is, the relationship of the pulse output speed is v4 < v1. Also, the number of pulses (X) output is the number of pulse signals required to operate the shut-off valve 41 from the stop position to the open position. Naturally, X is also the number of pulse signals required to operate the shut-off valve 41 from the open position to the stop position.

[0053] Now, the valve control unit 42 returns after opening the shut-off valve 41. Also, the valve control unit 42 returns when it determines that the shut-off valve 41 has already been opened (S4: YES), and also when it determines that although the shut-off valve 41 is closed but there is no opening instruction (S5: NO). Although it is stated that it returns for the sake of clarity of the processing flow, the valve control unit 42 actually shifts to step S1 and repeatedly executes this process during the operation of the air conditioner 1.

[0054] When the air conditioner 1 is operating normally without refrigerant leakage or power interruption, i.e., when the shutoff valve 41 is open, and it is determined that a refrigerant leakage has been detected (S1: YES), the valve control unit 42 outputs X pulses of a control signal to the pulse motor 41g at a pulse output speed (v1) to close the shutoff valve 41 (S2). At this time, the buzzer 60 in the refrigerant leakage detection unit 30a has already sounded.

[0055] The pulse output speed (v1) at this time is set to be faster than the pulse output speed in other processes that drive the shutoff valve 41 in order to quickly shut off the flow of refrigerant to the indoor units 3. In other words, when power is being supplied from the external power source 8, the valve control unit 42 increases the operating speed of the shutoff valve 41 as much as possible if refrigerant leakage is detected from any of the indoor units 3. As a result, by quickly isolating the corresponding indoor unit 3 from the refrigeration cycle, it is possible to prevent a large amount of refrigerant filled during the refrigeration cycle from leaking from that indoor unit 3 into the room.

[0056] Following step S2, the valve control unit 42 outputs a control signal to the pulse motor 41g at a pulse output speed (v2) of Y pulses as additional tightening, thereby reliably closing the shutoff valve 41 (S3). At this time, the pulse output speed (v2) is set to be smaller than the pulse output speed (v1) in order to ensure a large torque. Also, it is desirable that the number of pulses (Y) is equal to or larger than the number of pulses (X) described above.

[0057] In other words, the valve control unit 42 tightens the shutoff valve 41 by the entire displacement when the shutoff valve 41 is moved from the open position to the closed position, thereby ensuring a reliable closing. However, the value of the number of pulses (Y) for tightening shown here is only an example, and can be set appropriately based on the specifications of the shutoff valve 41 within the range of strength permitted.

[0058] This tightening process has the technical significance of preventing the above-mentioned pulse dropout, in addition to the technical significance of reliably closing the shutoff valve 41 to prevent refrigerant leakage. That is, if a pulse dropout occurs as a result of increasing the pulse output speed (v1) to quickly operate the shutoff valve, the valve rod 41e may stop before the closing position, making it impossible to close the refrigerant piping, and a small amount of refrigerant may continue to leak.

[0059] On the other hand, even if a pulse drop occurs and the valve rod 41e does not reach the closed position, the valve rod 41e can be moved to the closed position by executing the re-tightening process in step S3. Furthermore, in this re-tightening process, a control signal is output at a pulse output speed (v2) slower than the pulse output speed (v1), so that the tightening torque becomes larger and the valve rod 41e can be rotated and pressed against the valve seat 41d more firmly, thereby reliably bringing the shutoff valve 41 into the closed state.

[0060] Thereafter, the valve control unit 42 proceeds to step S4. In this case, the valve control unit 42 determines that the shutoff valve 41 is closed because the refrigerant leakage was detected and the shutoff valve 41 was closed (S4: YES). At this time, if an open command is not given, the valve control unit 42 determines that there is no open command (S5: NO) and returns.

[0061] When a refrigerant leak is detected in this manner, the valve control unit 42 executes the process in the order of step S1: YES, step S2, and step S3. Then, when the valve control unit 42 determines that a refrigerant leak has not been detected (S1: NO), or when the valve control unit 42 determines that a power cut has been detected (S7: YES), it determines whether the shutoff valve 41 is closed (S8). When the valve control unit 42 determines that the shutoff valve 41 is closed, that is, when a refrigerant leak or a power outage has already been detected (S8: YES), it proceeds to step S4. However, since the same determination is made in steps S8 and S4, when step S8: YES, it may proceed to step S5.

[0062] On the other hand, in step S8, when the valve control unit 42 determines that the shut-off valve 41 is not closed, that is, when no refrigerant leakage has been detected previously (S8: NO), the shut-off valve 41 closing operation at power-off is performed. Here, the shut-off valve 41 is closed (S9) by outputting X pulses to the pulse motor 41g at the pulse output speed (v3). At this time, the pulse output speed (v3) is set slower than the pulse output speed (v1) when closing the shut-off valve 41 when refrigerant leakage is detected. That is, the relationship of the pulse output speed is v4 < v1, and when power-off is detected, the valve control unit 42 reduces the operating speed of the shut-off valve 41 compared to when power is supplied from the external power supply 8 and refrigerant leakage is detected.

[0063] This is because when power-off is detected, the power for operating the shut-off valve 41 is supplied from the power storage unit 5, so as to reduce the power consumption during driving of the shut-off valve 41 and prevent the power supply from the power storage unit 5 from being insufficient.

[0064] Also, in this embodiment, the relationship of the pulse output speeds in each process is v1 > v2, v1 > v3, v1 > v4. That is, the pulse output speed (v1) has the fastest operating speed and the least torque. Also, for the other pulse output speeds, for example, v2 = v3 = v4 can be set, or v2, v3, v4 can be set to different values. In other words, when power is supplied from the external power supply 8 and refrigerant leakage is detected, the valve control unit 42 controls the operating speed of the shut-off valve 41 to be the fastest. In a normal state where there is no cooling leakage and no power-off, the valve control unit 42 repeats NO in step S1, NO in S7, and NO in S4, and the shut-off valve 41 remains in the open state.

[0065] In this way, in the air conditioner 1, when refrigerant leakage is detected, in the shut-off unit 4, the refrigerant leakage is quickly shut off by the shut-off valve 41, and the refrigerant leakage is surely shut off by performing additional tightening.

[0066] Furthermore, in the air conditioner 1, the shutoff unit 4 controls the operation speed of the shutoff valve 41 to be different when power is being supplied from the external power source 8 and when power is being supplied from the power storage unit 5. Furthermore, in the air conditioner 1, the shutoff unit 4 controls the operation speed of the shutoff valve 41 to be different when a refrigerant leak is detected and when a power cutoff is detected. Furthermore, in the air conditioner 1, the shutoff unit 4 controls the operation speed of the shutoff valve 41 to be different when a refrigerant leak is detected while power is being supplied from the external power source 8 and when a power cutoff is detected. This makes it possible to control the shutoff valve 41 according to the supplied power.

[0067] According to the air conditioner 1 described above, the following effects can be obtained. The air conditioner 1 includes an outdoor unit 2, an indoor unit 3 connected to the outdoor unit 2 by a refrigerant piping, a shutoff unit 4 capable of shutting off the flow of refrigerant in the refrigerant piping between the outdoor unit 2 and the indoor unit 3, and a refrigerant leakage detection unit 30a that detects refrigerant leakage. The shutoff unit 4 includes a shutoff valve 41 that shuts off the flow of refrigerant in the refrigerant piping, and a valve control unit 42 that controls the operation of the shutoff valve. The shutoff valve 41 is an electric valve driven by a motor, and when a refrigerant leakage is detected by the refrigerant leakage detection unit 30a, the valve control unit 42 controls the shutoff valve to close at an operating speed (v1), and then controls the shutoff valve to be tightened at an operating speed (v2) slower than the operating speed (v1).

[0068] In this way, when a refrigerant leak is detected, the flow of refrigerant to the indoor unit 3 can be quickly cut off by closing the shutoff valve 41 at a relatively fast operating speed (v1), and by further tightening at a relatively slow operating speed (v2), no pulse missing occurs and the shutoff valve 41 can be closed reliably.

[0069] Furthermore, the configuration capable of quickly and reliably closing the shutoff valve 41 as described above is extremely useful in terms of ensuring safety since it reduces the risk of ignition of the leaked refrigerant when the refrigerant is a flammable refrigerant.

[0070] The air conditioner 1 is equipped with a buzzer 60, and the valve control unit 42 sounds the buzzer 60 when the refrigerant leakage detection unit 30a detects a refrigerant leakage. This allows for prompt notification when even a slight risk of refrigerant leakage is anticipated. In addition, when an electric valve, particularly a motor valve described below, is used as the shutoff valve 41, if the shutoff valve 41 is already in the closed position when the shutoff valve 41 is tightened, when pulse current is applied for tightening, a valve body such as the rotor 51i may collide with a stopper such as the abutment portion 51f due to backlash in the reduction mechanism, causing repeated collision noises.

[0071] Therefore, by sounding the buzzer 60 before retightening, the impact sound can be masked by the sound of the buzzer 60, so that the user will not be bothered by it. Also, there is a risk that the user will feel uneasy if the sound of the shutoff valve 41 being closed occurs when the buzzer 60 sounds, but sounding the buzzer 60 can reduce such a risk. It is also possible to prevent the user from mistakenly thinking that the air conditioner 1 has broken down because of a sound.

[0072] Furthermore, the valve control unit 42 controls the operating speed (v1) of the shutoff valve 41 when a refrigerant leak is detected by the refrigerant leak detection unit 30a so that it is faster than the operating speed (v4) when opening the shutoff valve 41. This makes it possible to quickly shut off the flow of refrigerant to the indoor unit 3.

[0073] Furthermore, when a refrigerant leak is detected by the refrigerant leak detection unit 30a, the valve control unit 42 makes the operating speed (v2) when retightening the shutoff valve 41 equal to the operating speed (v4) when opening the shutoff valve 41. This allows the shutoff valve 41 to be opened with the same torque as when retightening, ensuring that the valve can be opened reliably. Note that making them equal here includes a state in which the operating speed (v2) when retightening is within an allowable range of about 10% of the operating speed (v4) when opening the shutoff valve 41.

[0074] Furthermore, the valve control unit 42 sets the number of pulses (Y) output when further tightening the shutoff valve 41 in the event that a refrigerant leak is detected by the refrigerant leak detection unit 30a to be equal to the number of pulses (X) output when performing a valve closing operation of the shutoff valve 41 from fully open to fully closed. This makes it possible to reliably shut off the flow of refrigerant to the indoor unit 3 by further tightening the valve after the valve closing operation.

[0075] The air conditioner 1 includes a shutoff unit 4 capable of shutting off the flow of refrigerant in the refrigerant piping connecting the outdoor unit 2 and the indoor unit 3, a power storage unit 5 capable of supplying power to the shutoff unit 4 when the supply of power from an external power source 8 is cut off, a refrigerant leakage detection unit 30a that detects a refrigerant leak, and a power cutoff detection unit 42a that detects that the supply of power from the external power source 8 has been cut off. The shutoff unit 4 includes a shutoff valve 41 that is driven by a motor and shuts off the flow of refrigerant in the refrigerant piping, and a valve control unit 42 that controls the operation of the shutoff valve 41.

[0076] Then, when a refrigerant leakage is detected or when it is detected that the power supply from the external power source 8 has been cut off, the valve control unit 42 closes the shut-off valve 41 and makes the operating speed of the shut-off valve 41 when a refrigerant leakage is detected faster than the operating speed of the shut-off valve 41 when it is detected that the power supply from the external power source 8 has been cut off.

[0077] This makes it possible to operate shutoff valve 41 according to the supplyable power when power is supplied from power storage unit 5, which has a smaller capacity than the power from external power source 8. This reduces the risk that shutoff valve 41 will not be able to operate due to a power shortage in power storage unit 5, and also makes it possible to reliably and quickly shut off the refrigerant.

[0078] Furthermore, the air conditioner 1 slows down the operating speed of the shutoff valve 41 when a refrigerant leak is detected, compared to the operating speed of the shutoff valve 41 when power is being supplied from the power storage unit 5. This allows the flow of refrigerant to be quickly shut off in the event of a refrigerant leak, suppresses further leakage of flammable refrigerant, and improves safety. Although it is desirable to have a fast operating speed when the power is cut off, the operating speed of the shutoff valve 41 when power is being supplied from the power storage unit 5 is slowed down to minimize the worst case scenario of the shutoff valve being unable to be operated due to insufficient power in the power storage unit 5 at a critical time when the valve needs to be closed.

[0079] Furthermore, in the air conditioner 1 of this embodiment, multiple indoor units 3 are provided in parallel in a single refrigerant piping system, the shutoff unit 4 is provided commonly to the multiple indoor units 3, and the valve control unit 42 controls the operation of multiple shutoff valves 41 provided in each of the multiple indoor units 3. This allows the multiple indoor units 3 to be controlled collectively, reducing the risk of the configuration becoming complicated.

[0080] Furthermore, the air conditioner 1 can be modified as appropriate without departing from the spirit and scope of the invention. For example, as shown in Fig. 6, when the air conditioner 1 is provided with multiple indoor units 3 in a single refrigerant piping system and each indoor unit 3 is installed in a different air-conditioned space 100, the air conditioner 1 can be configured to have a shutoff unit 4 in each indoor unit 3. In other words, when multiple indoor units 3 are provided in parallel in a single refrigerant piping system, multiple shutoff units 4 can be provided individually for the multiple indoor units 3, and the valve control unit 42 of each shutoff unit 4 can be configured to control the operation of the shutoff valve 41 provided in the corresponding indoor unit 3.

[0081] Even in the case of such a configuration, it is possible to reduce the risk of the shut-off valve 41 not being able to operate due to a power shortage, and it is possible to quickly shut off the refrigerant. Furthermore, it is possible to further tighten the shut-off valve 41 to more reliably shut off refrigerant leakage, etc., so it is possible to obtain the same effects as in the embodiment in that the shut-off valve 41 can be operated reliably and the refrigerant can be shut off quickly and reliably depending on the situation.

[0082] In the embodiment, the shutoff valve 41 is exemplified as a type in which the valve rod 41e is moved linearly. However, as the shutoff valve 41, for example, an electric rotary valve 51, also called a ball valve, as shown in FIG. 7 can be used. This electric rotary valve 51 has a housing portion 51c in which a first opening 51a serving as an inlet or outlet for the refrigerant and a second opening 51b serving as an inlet or outlet for the refrigerant are formed, and a rotor 51d disposed in the housing portion 51c. In this embodiment, this rotor 51d is formed in a spherical shape, and an internal flow path 51e capable of connecting between the first opening 51a and the second opening 51b is formed inside the rotor 51d. The rotor 51d may be formed in a columnar shape capable of rotating around a rotation axis (J1).

[0083] Then, by rotating the rotating body 51d around the rotation axis (J1) to change the position of the internal flow path 51e, it is possible to switch between a state in which the first opening 51a and the second opening 51b are connected by the internal flow path 51e and the shut-off valve 41 is opened, as shown as a flow path open state, or a state in which the first opening 51a and the second opening 51b are not connected and the shut-off valve 41 is closed, as shown as a flow path open state.

[0084] At this time, as shown as an open stopper state, the accommodation portion 51c has a contact portion 51f protruding from the inner wall toward the inner periphery, and the rotor 51d has a groove portion 51g recessed toward the inner periphery. When the rotor 51d is rotated around the rotation axis (J1), one end 51h of the groove portion 51g comes into contact with the contact portion 51f and the rotation is stopped, the first opening 51a and the second opening 51b are connected by the internal flow path 51e, and the shutoff valve 41 is in an open state. On the other hand, when the other end 51i of the groove portion 51g comes into contact with the contact portion 51f from the opposite side and the rotation is stopped, the first opening 51a and the second opening 51b are not connected by the internal flow path 51e, and the shutoff valve 41 is in a closed state.

[0085] 8, in the breaking unit 4, a gear 51j as a reducer is disposed on the output shaft of a pulse motor 41g, and a ball as a rotor 51d is driven via the gear 51j. This makes it possible to apply a torque sufficient to rotate the rotor 51d while sliding it against the inner wall of the housing portion 51c.

[0086] Even in a configuration using such an electric rotary valve 51 as the shutoff valve 41, the operating speed of the shutoff valve 41 when a refrigerant leak is detected can be controlled to be faster than the operating speed of the shutoff valve 41 when it is detected that the power supply from the external power source 8 has been cut off, thereby reducing the risk that the shutoff valve 41 will not be able to operate due to a power shortage and making it possible to quickly cut off the refrigerant, and other effects similar to those of the embodiment can be obtained. In other words, the configuration of the air conditioner 1 can be more effective when a pulse motor valve or a ball valve driven by a motor via the gear 51j is used as the shutoff valve 41.

[0087] Also, the buzzer 60 can be configured to be provided in the indoor control unit 30. In this case, as shown in Fig. 9, the refrigerant leakage detection unit 30a judges whether refrigerant gas has been detected (S11), and if refrigerant gas has not been detected (S1: NO), it returns, that is, moves to step S11 and continues to detect refrigerant gas, while if refrigerant gas has been detected (S1: YES), it transmits a refrigerant leakage detection signal to the indoor control unit 30 (S12). Then, the refrigerant leakage detection unit 30a judges whether a reset operation has been performed or a reset signal has been received (S14), and if a reset operation has not been performed or a reset signal has not been received (S14: NO), it waits, while if the countermeasure against the refrigerant leakage has been completed and a reset operation has been performed or a reset signal has been received (S14: YES), it stops the buzzer 60 from sounding (S15) and returns.

[0088] The indoor control unit 30 also determines whether or not a refrigerant leakage detection signal has been received from the refrigerant leakage detection unit 30a (S21), and if a refrigerant leakage detection signal has not been received (S21: NO), executes normal operation processing (S25), and returns, i.e., proceeds to step S21 and continues to monitor for receipt of a refrigerant leakage detection signal, whereas if a refrigerant leakage detection signal has been received (S21: YES), it transmits a refrigerant leakage signal to the cutoff unit 4 (S22) and sounds the buzzer 60 (S31). After that, the indoor control unit 30 determines whether an open command has been input (S23), and if there has been no open command input (S23: NO), it waits, whereas if there has been an open command input (S23: YES), it transmits an open command to the cutoff unit 4 (S24), stops sounding the buzzer 60, and returns.

[0089] Even with this configuration, by sounding the buzzer 60 before retightening, the impact sound can be masked by the sound of the buzzer 60, so that the user will not be bothered. It is also possible to prevent the user from mistakenly thinking that the air conditioner 1 has broken down due to a sound. Furthermore, the buzzer may be provided in the valve control unit 42, or in multiple locations.

[0090] Furthermore, in the embodiment, a configuration has been illustrated in which a dedicated valve control section 42 is provided in the shutoff unit 4, but it is also possible to configure it to share the indoor control section 30, or to configure it to share the indoor control section 30 as a control section of an operation panel that inputs operations to start and stop the operation of each indoor unit 3 and displays the temperature of the air-conditioned space 100. The control section of the operation panel can also be used as the indoor control section 30.

[0091] Furthermore, although the embodiment has been described as an example of a configuration in which the gas sensor 9 is provided in each indoor unit 3, a configuration in which multiple gas sensors 9 are provided in one air-conditioned space 100 may also be used. Furthermore, the gas sensor 9 is not limited to one that detects the refrigerant, and may also be configured to detect leakage based on changes in the pressure or flow rate of the refrigerant, or in combination with these.

[0092] The above-described embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims. In addition, the configurations exemplified in each embodiment can be combined as appropriate. [Explanation of symbols]

[0093] In the drawings, 1 is an air conditioner, 2 is an outdoor unit, 3 is an indoor unit, 4 is a shutoff unit, 5 is a power storage unit, 6 is a first piping (refrigerant piping), 7 is a second piping (refrigerant piping), 8 is an external power source, 21 is an outdoor heat exchanger, 22 is an outdoor expansion valve, 24 is a four-way valve, 25 is a compressor, 30 is an indoor control unit (control unit), 30a is a refrigerant leakage detection unit, 41 is a shutoff valve, 42 is a valve control unit (control unit), 42a is a power supply shutoff detection unit, 51 is an electric rotary valve (shutoff valve; ball valve), 51i is a rotor, 51f is a contact unit (stopper portion), and 60 is a buzzer (sound output unit).

Claims

1. The outdoor unit, an indoor unit connected to the outdoor unit by a refrigerant pipe; a shutoff unit capable of shutting off the flow of refrigerant in the refrigerant piping between the outdoor unit and the indoor unit; A refrigerant leakage detection unit that detects a refrigerant leakage, The shutoff unit includes a shutoff valve that shuts off the flow of refrigerant in the refrigerant piping, and a control unit that controls an operation of the shutoff valve, The shutoff valve is an electric valve driven by a motor, and is configured as a pulse motor valve whose opening degree can be adjusted by inserting the tip of a movable valve stem into a valve seat, When a refrigerant leak is detected by the refrigerant leak detection unit, the control unit controls the shut-off valve to close at an operating speed (v1), and then controls the shut-off valve to further tighten in the direction of inserting the tip of the valve rod into the valve seat at an operating speed (v2) slower than the operating speed (v1).

2. The outdoor unit, an indoor unit connected to the outdoor unit by a refrigerant pipe; a shutoff unit capable of shutting off the flow of refrigerant in the refrigerant piping between the outdoor unit and the indoor unit; A refrigerant leakage detection unit that detects a refrigerant leakage, The shutoff unit includes a shutoff valve that shuts off the flow of refrigerant in the refrigerant piping, and a control unit that controls an operation of the shutoff valve, the shutoff valve is an electrically operated valve driven by a motor, and is configured as a ball valve having a first opening and a second opening serving as an inlet and an outlet for the refrigerant, a rotor capable of adjusting an opening degree by rotating to open or close the first opening and the second opening, and a stopper that restricts the rotation of the rotor to a state in which the first opening and the second opening are closed, When a refrigerant leak is detected by the refrigerant leak detection unit, the control unit controls the shut-off valve to close at an operating speed (v1), and then controls the shut-off valve to further tighten the rotating body in a direction to contact the stopper at an operating speed (v2) slower than the operating speed (v1).

3. 3. The air conditioner according to claim 1, wherein the refrigerant is a flammable refrigerant.

4. The air conditioner according to any one of claims 1 to 3, further comprising a sound output unit that outputs a sound when a refrigerant leak is detected by the refrigerant leak detection unit.

5. The indoor units are provided in parallel in a single refrigerant piping system, The shutoff unit is provided in common to a plurality of the indoor units, The air conditioner according to claim 1 , wherein the control unit controls operations of a plurality of the shutoff valves provided in a plurality of the indoor units, respectively.

6. The indoor units are provided in parallel in a single refrigerant piping system, The blocking unit is provided in plurality for each of the indoor units, The air conditioner according to claim 1 , wherein the control unit of each of the shutoff units controls operation of the shutoff valve provided in the corresponding indoor unit.

7. The air conditioner according to any one of claims 1 to 6, wherein the control unit sets the operating speed (v1) of the shutoff valve when a refrigerant leak is detected by the refrigerant leak detection unit to be faster than the operating speed (v4) when the shutoff valve is opened.

8. 8. The air conditioner according to claim 1, wherein the control unit sets an operating speed (v2) when tightening the shutoff valve when a refrigerant leak is detected by the refrigerant leak detection unit to be equal to an operating speed (v4) when opening the shutoff valve.

9. 9. The air conditioner according to claim 1, wherein the control unit sets the number of pulses output when further tightening the shutoff valve when a refrigerant leak is detected by the refrigerant leak detection unit to be equal to the number of pulses output when operating the shutoff valve from fully open to fully closed.

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