JP2007107781A - Air conditioning unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an air conditioning unit controlled by a microcomputer or the like, which can respond to a failure in a controlled part even in the event of a control failure. <P>SOLUTION: In the air conditioning unit comprising an inverter 53 driving a compressor 10B according to control of the microcomputer 52, a switch response circuit 55 is provided on a line for supplying an inverter driving voltage for driving the inverter 53, and the inverter driving voltage is cut by the switch response circuit 55 in interlocking with switching operation of a high-pressure switch 51A arranged in a discharge-side pipe of the compressor 10B. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an air conditioner including a compressor driven by an inverter.

Conventionally, control using a microcomputer has been widely used in air conditioners. For example, when an abnormal value is detected by various sensors such as a current sensor and a temperature sensor, the microcomputer-controlled air conditioner stops the compressor in response to this abnormality, and then the abnormal part and the degree of abnormality (For example, refer to Patent Document 1).
JP 2004-205118 A

  By the way, in the microcomputer-controlled air conditioner, if an abnormality occurs in the operation of the microcomputer itself, even if an abnormality occurs in the operation of the controlled part (for example, the compressor) of the air conditioner, this abnormality is dealt with. There was a problem that it was difficult to do. Although abnormal operation of the microcomputer is extremely rare, the possibility that it may occur due to a bug in the control program that operates the microcomputer cannot be denied. For this reason, even if an abnormality occurs in the operation of the microcomputer, it has been desired to be able to cope with the abnormality of the controlled part.

  The present invention has been made in view of the above-described circumstances, and enables an air conditioner controlled by a microcomputer or the like to cope with an abnormality occurring in a controlled part even if an abnormality occurs in the control. The purpose is that.

In order to solve the above problems, the present invention provides an air conditioner including a compressor driven by an inverter, disposed on a power supply line for driving the inverter, and disposed on a discharge side pipe of the compressor. A power switching means for cutting the power supply line is provided in conjunction with the switching operation of the pressure switch provided.
According to this configuration, when the pressure switch disposed in the discharge side piping of the compressor is switched, for example, when a high pressure exceeding a predetermined pressure is detected, the drive power of the inverter is cut off in conjunction with this switching operation. Therefore, the compressor can be stopped safely and promptly by stopping the inverter itself without going through control by a microcomputer or the like that drives the inverter. Further, since the drive power supply of the inverter is cut off instead of the power supply of the compressor itself, it can be easily realized as a circuit for switching a low voltage power supply.

  In the present invention, the pressure switch may be a switch that turns off when the pressure in the discharge-side piping of the compressor exceeds a predetermined pressure.

  The power supply switching means may output a control signal to the control means in conjunction with the pressure switch.

  Furthermore, the power supply switching unit may be configured to cut off the power supply line after a predetermined time has elapsed since the switching of the pressure switch.

  The power supply switching unit may be configured to connect the power supply line when the pressure switch is restored.

  According to the present invention, when the pressure switch arranged in the discharge side piping of the compressor is switched, for example, when a high pressure exceeding a predetermined pressure is detected, the inverter-driven compression is performed without control by a microcomputer or the like. Since the machine can be stopped, for example, even if an abnormality occurs in the microcomputer that controls the air conditioner, the compressor can be reliably stopped in response to an abnormality in the pressure of the pipe. High reliability can be ensured.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram of an air conditioner 1 according to an embodiment of the present invention.
This air conditioner 1 is configured such that an outdoor unit 1A, 1B is connected in parallel to an inter-unit pipe 9 including a gas pipe 5 and a liquid pipe 7, and indoor units 3A, 3B are connected in parallel. The

The outdoor unit 1A includes a constant-capacity compressor 10A and an inverter-driven variable-capacity compressor 10B. The compressors 10A and 10B are connected in parallel, and the suction side of the compressors 10A and 10B is suctioned. A pipe 20A is connected, an accumulator 11A is connected to the suction pipe 20A, a discharge pipe 21A is connected to the discharge side, and a four-way valve 13A is connected to the discharge pipe 21A via an oil separator 12A. Further, an outdoor heat exchanger 14A, an outdoor expansion valve 15A, and a receiver tank 16A are sequentially connected to the outdoor refrigerant pipe 18A connected to the four-way valve 13A.
The outdoor unit 1A includes a bypass pipe 22A that connects the discharge pipe 21A and the upper part of the receiver tank 16A. The bypass pipe 22A is provided with a control valve 25A. For example, a normally closed electromagnetic valve is applied to the control valve 25A. An outdoor fan 17A for sending air to the outdoor heat exchanger 14A is disposed adjacent to the outdoor heat exchanger 14A.

  The outdoor unit 1B has an accumulator 11B connected to a suction pipe 20B of a constant capacity compressor (AC compressor) 10C, a four-way valve 13B connected to a discharge pipe 21B via an oil separator 12B, and a four-way valve 13B. The outdoor heat exchanger 14B, the outdoor expansion valve 15B, and the receiver tank 16B are sequentially connected to the outdoor refrigerant pipe 18B connected to. The outdoor unit 1B includes a bypass pipe 22B that connects the discharge pipe 21B and the upper part of the receiver tank 16B, and a control valve 25B is provided in the bypass pipe 22B. For example, a normally closed electromagnetic valve is applied to the control valve 25B. An outdoor fan 17B that blows air to the outdoor heat exchanger 14B is disposed adjacent to the outdoor heat exchanger 14B.

  In the indoor unit 3A, an indoor expansion valve 38A and an indoor heat exchanger 34A are sequentially connected to the indoor refrigerant pipe 39A, one end of the indoor refrigerant pipe 39A is connected to the gas pipe 5, and the other end is connected to the indoor heat exchanger 34A and the indoor expansion valve. Each is connected to the liquid pipe 7 via 38A. An indoor fan 37A for blowing air to the indoor heat exchanger 34A is disposed adjacent to the indoor heat exchanger 34A. Since the indoor unit 3B has the same configuration as the indoor unit 3A, description thereof is omitted.

  As shown in FIG. 2, the compressors 10 </ b> A, 10 </ b> B, and 10 </ b> C are four-horsepower (ps) constant-capacity rated compressors, and the compressor 10 </ b> B has variable capacity (number of rotations) according to the air conditioning load A 6-horsepower variable-variable inverter compressor that can be controlled to 10 hp, and the compressor 10C is a 10-horsepower constant-capacity rated compressor. Accordingly, the outdoor unit 1A is a 10 horsepower variable capacity outdoor unit, and the outdoor unit 1B is a 10 horsepower constant capacity (rated) outdoor unit.

A high pressure switch 51A (pressure switch) is disposed on the discharge side piping of the compressors 10A and 10B, and a high pressure switch 51B is disposed on the discharge side piping of the compressor 10C.
These high-pressure switches 51A and 51B are switches that are normally set and are turned off when the pressure in the discharge-side piping exceeds a predetermined pressure reference. The operations of the compressors 10A, 10B, and 10C are controlled according to the on / off of the high-voltage switches 51A and 51B.

  On the other hand, although only two indoor units 3A and 3B are shown in FIG. 1, a large number of indoor units are actually provided so that the total horsepower of these indoor units is 20 horsepower. For example, the indoor unit 3A has 5 horsepower, the indoor unit 3B has 4 horsepower, and the total horsepower of an indoor unit (not shown) is 11 horsepower.

In the air conditioner 1, during the cooling operation, as shown in FIG. 1, the four-way valves 13A and 13B are switched to the dotted line positions (positions during the cooling operation). The refrigerant discharged from the compressors 10A, 10B, and 10C passes through the oil separators 12A and 12B and the four-way valves 13A and 13B, and then enters the outdoor heat exchangers 14A and 14B, where they are condensed. Then, the liquid flows through the outdoor expansion valves 15A and 15B and the receiver tanks 16A and 16B, and flows into the indoor units 3A and 3B.
The refrigerant that has flowed into the indoor units 3A and 3B enters the indoor expansion valves 38A and 38B and the indoor heat exchangers 34A and 34B, evaporates here, and then flows through the gas pipe 5 to be divided into the outdoor units 1A and 1B. Then, the divided refrigerant is returned to the compressors 10A, 10B, and 10C via the four-way valves 13A and 13B and the accumulators 11A and 11B.

During the heating operation, the four-way valves 13A and 13B are switched to the solid line positions (positions during the heating operation). The refrigerant discharged from the compressors 10A, 10B, and 10C passes through the oil separators 12A and 12B and the four-way valves 13A and 13B, then flows through the gas pipe 5 and flows into the indoor units 3A and 3B, as indicated by solid arrows. To do.
The refrigerant that has flowed into the indoor units 3A and 3B enters the indoor heat exchangers 34A and 34B, condenses, and then flows through the liquid pipe 7 through the indoor expansion valves 38A and 38B, and enters the outdoor units 1A and 1B. Divide. Then, the divided refrigerant passes through the receiver tanks 16A and 16B and the outdoor expansion valves 15A and 15B and enters the outdoor heat exchangers 14A and 14B. Then, it returns to compressor 10A, 10B, 10C.

  The air conditioner 1 includes temperature sensors 40A and 40B that measure the temperature of the room in which the indoor units 3A and 3B are disposed (the temperature of the intake air of the indoor units 3A and 3B), and the outdoor temperature (the suction of the outdoor units 1A and 1B). Temperature sensors 41A and 41B for measuring the temperature of the air), temperature sensors 42A and 42B for measuring the temperature of the air blown from the indoor units 3A and 3B, and the like. The signals of these sensors are output to the controller 100.

The controller 100 controls the operation of the outdoor units 1A and 1B and the indoor units 3A and 3B based on signals from the sensors. Specifically, in order to control the total output of the outdoor units 1A and 1B in the range of 1 to 6 ps, the controller 100 operates the variable capacity compressor 10B of the outdoor unit 1A with reference to FIG. Control within that variable range.
In order to control the total output within the range of 7 to 10 ps, the controller 100 operates the compressor 10A (4 ps) having a constant capacity of the outdoor unit 1A and then uses the remaining 3 to 6 ps for the variable capacity compressor 10B. Control by driving.
In addition, in order to control the total output in the range of 11 to 16 ps, the controller 100 allows the compressor 10C (10 ps) having a constant capacity of the outdoor unit 1B to be operated, and the remaining 1 to 6 ps is used for the outdoor unit 1A. This is controlled by the operation of the variable capacity compressor 10B.
Further, the controller 100 operates the compressor 10C (10 ps) having a constant capacity of the outdoor unit 1B and the compressor 10A (4 ps) having a constant capacity of the outdoor unit 1A in order to control the total output within a range of 17 to 20 ps. The remaining 3 to 6 ps is controlled by the operation of the variable capacity compressor 10B of the outdoor unit 1A.

  By the way, the discharge side pressure of the compressors 10A, 10B, and 10C increases when the load in the indoor units 3A and 3B increases steeply or when the operation of the compressors 10A, 10B, and 10C becomes abnormal. There is. When the discharge side pressure exceeds the reference, the high pressure switches 51A and 51B described above are switched off. The air conditioner 1 performs an operation of stopping the compressors 10A, 10B, and 10C in accordance with the switching of the high pressure switches 51A and 51B.

  Specifically, the constant capacity compressors 10A and 10C are driven / stopped when a power supply current from a power supply device (not shown) is turned on / off according to control of a controller 100 described later. Here, magnet switches (not shown) are arranged on the power supply lines for the compressors 10A and 10C, and these magnet switches are interlocked with the high pressure switches 51A and 51B when the high pressure switches 51A and 51B are turned off. And a mechanism for cutting. Therefore, when the high voltage switches 51A and 51B are switched off, the power supply to the compressors 10A and 10C is stopped by the operation of the magnet switch, so that the compressors 10A and 10C are stopped.

On the other hand, the compressor 10 </ b> B is driven by an inverter according to the control of the controller 100.
FIG. 2 is a diagram showing a configuration for driving the compressor 10 </ b> B, and in particular, a diagram showing a functional configuration of the compressor drive control unit 50.
An inverter 53 that drives the compressor 10B is connected to a microcomputer 52 (control means). The microcomputer 52 outputs an inverter drive waveform signal DS to the inverter 53 according to the control of the controller 100, and the inverter 53 operates according to the inverter drive waveform signal DS. The inverter 53 is supplied with an inverter drive voltage supplied from the power supply circuit 54. The power supply circuit 54 supplies, for example, a DC voltage of 5 volts, unlike a power supply apparatus (not shown) that supplies power (for example, AC 200 volts) to each part of the air conditioner 1 including the compressor 10B.

  The microcomputer 52 is connected to a high voltage switch 51A via a switch response circuit 55 (power supply switching means). When the high voltage switch 51A detects a pressure exceeding the reference and switches off, it responds to this. Then, an abnormal signal FS (control signal) is input from the switch response circuit 55 to the microcomputer 52. When the microcomputer 52 detects that the abnormal signal FS is input, the microcomputer 52 changes the inverter drive waveform signal DS output to the inverter 53 and stops the compressor 10B.

  Further, the switch response circuit 55 is arranged on the supply line of the inverter drive voltage reaching the inverter 53 from the power supply circuit 54. When the high voltage switch 51A is switched off, the supply line is cut off and the inverter to the inverter 53 is disconnected. The drive voltage supply is forcibly cut off.

  FIG. 3 is a circuit diagram showing a specific configuration example of the switch response circuit 55. FIG. 3 shows a microcomputer 52 and an inverter 53 for ease of understanding.

  As shown in FIG. 3, the switch response circuit 55 includes a photocoupler PC1 that is turned on / off in response to the on / off of the high-voltage switch 51A, and an abnormal signal FS that is output to the microcomputer 52 in response to the on / off of the photocoupler PC1. A transistor TR1 for switching the level of the transistor TR2, a transistor TR2 for switching on / off of the inverter drive voltage Vcc supplied to the inverter 53, a transistor BRT1 with a built-in resistor for turning on / off the transistor TR2 according to the state of the transistor TR1, Each part such as BRT2 is provided.

  More specifically, the switch response circuit 55 includes a photocoupler PC1 connected to the high-voltage switch 51A via a resistor R1, and an AC 200-volt circuit including the high-voltage switch 51A and the switch via the photocoupler PC1. A DC 5 volt circuit including other parts of the response circuit 55 is connected.

The light emitting diode of the photocoupler PC1 is connected in parallel with the diode D1 and the resistor R2 in the reverse direction, and emits light when the high voltage switch 51A is on.
On the other hand, a DC voltage of 5 volts is applied to one end on the light receiving side of the photocoupler PC1, and one end of a capacitor C1 is connected in series to the other end via a resistor R3. The other end of the capacitor C1 is grounded. While the light emitting diode of the photocoupler PC1 is emitting light, a current flows to the light receiving side of the photocoupler PC1, and the capacitor C1 is charged.

The base of the NPN transistor TR1 is connected to one end of the capacitor C1 via a resistor R4. A DC voltage of 5 volts is applied to the collector of the transistor TR1 via a resistor R6, the base-emitter is connected via an external resistor R5, and the emitter is grounded.
Further, a signal line connected to the inverter 53 is connected to the collector of the transistor TR1. The voltage of the signal line is input to the microcomputer 52 as the abnormal signal FS. When the voltage of the signal line, that is, the abnormal signal FS is at the low level, the microcomputer 52 determines that the operation is normal, and the abnormal signal FS is at the high level. The microcomputer 52 determines that the high pressure switch 51A has been turned off by detecting a pressure exceeding the reference.

The base of the NPN transistor BRT1 is connected to the collector of the transistor TR1 via the resistor R7. The emitter of the transistor BRT1 is grounded, and a DC voltage of 5 volts is applied to the collector via the resistor R8.
The collector of the transistor BRT1 is connected to the cathode side of the diode D2, and the anode side of the diode D2 is connected to the base of the PNP transistor BRT2.
A DC voltage of 5 volts is applied to the emitter of the transistor BRT2, and the collector is grounded through a resistor R9.
Further, the collector of the transistor BRT2 is connected to the base of the transistor TR2 via the resistor R10. A DC voltage of 5 volts is applied to the emitter of the transistor TR2, and the emitter and base are connected via an external resistor R11. The collector of the transistor TR2 is connected to the inverter 53, and the inverter drive voltage Vcc is supplied to the inverter 53 via this connection line. This connection line is grounded via a resistor R12.

The operation of the switch response circuit 55 is as follows.
When the high voltage switch 51A is on, the light emitting diode built in the photocoupler PC1 emits light, and the light receiving side of the photocoupler PC1 is turned on. As a result, the capacitor C1 is charged and the transistor TR1 is turned on so that a collector-emitter current flows.
In this state, the abnormal signal FS that matches the potential of the collector of the transistor TR1 is at the low level, and the abnormal signal FS at the low level is output to the microcomputer 52.
Here, since an AC voltage is applied to the light emitting diode of the photocoupler PC1, the light emission is intermittent. In this non-light emission time during intermittent light emission, no current flows to the light receiving side of the photocoupler PC1, but if the non-light emission time is short, a voltage is supplied from the capacitor C1 to the base of the transistor TR1. The transistor TR1 is kept on.

When the transistor TR1 is on, the voltage between the base and the emitter of the transistor BRT1 is low, and the transistor BRT1 is off. Accordingly, since the base potential of the transistor BRT2 connected to the collector of the transistor BRT1 is high, the emitter-base voltage is low in the transistor BRT2, and the transistor BRT2 is also off.
For this reason, in the transistor TR2, since the base potential is low and the voltage between the emitter and the base is sufficiently high, the transistor TR2 is turned on. As a result, the inverter drive voltage Vcc is supplied to the inverter 53 from the collector of the transistor TR2.

  In summary, when the high voltage switch 51 </ b> A is on, a low level abnormality signal FS is output to the microcomputer 52, and an inverter drive voltage Vcc of approximately 5 volts is supplied to the inverter 53.

Here, when the high pressure switch 51A detects a pressure exceeding the reference and switches off, the light emitting diode of the photocoupler PC1 stops emitting light, and the light receiving side of the photocoupler PC1 switches off. Along with this, the transistor TR1 is turned off when the base potential drops, and the collector potential of the transistor TR1 becomes high.
For this reason, the abnormal signal FS output to the microcomputer 52 is switched to the high level.
The microcomputer 52 detects that the abnormal signal FS has been switched to the High level, determines that the high pressure switch 51A has detected a pressure exceeding the reference, and performs abnormal control such as stopping the compressor 10B.

Further, when the transistor TR1 is turned off, the base potential of the transistor BRT1 is increased, so that the transistor BRT1 is turned on. Along with this, a forward current flows through the diode D2 connected to the collector of the transistor BRT1, and the base potential of the transistor BRT2 is lowered, so that the transistor BRT2 is turned on.
Then, when the potential of the collector of the transistor BRT2 is increased, the transistor TR2 is turned off, and the supply of the inverter drive voltage Vcc output to the inverter 53 is turned off.

Thus, since the supply of the inverter drive voltage Vcc to the inverter 53 is stopped by turning off the high-voltage switch 51A, the operation of the inverter 53 is stopped and the compressor 10B is stopped.
As described above, when the high-voltage switch 51A is turned off, the abnormal signal FS output to the microcomputer 52 is switched from the low level to the high level, so the microcomputer 52 detects this and controls the inverter 53. Then, the compressor 10B is stopped.
However, in the air conditioner 1, the microcomputer 52 may not operate normally due to a bug in the control program of the microcomputer 52 or the like. Furthermore, in the situation where the microcomputer 52 cannot operate normally, the possibility that the pressure in the discharge side piping of the compressor 10B exceeds the above standard is extremely low, but cannot be completely denied.
In the air conditioner 1 of the present embodiment, when the high pressure switch 51A detects a pressure exceeding the reference and is turned off, the inverter drive voltage Vcc supplied to the inverter 53 is turned off, and the inverter 53 is automatically turned on. And it is stopped compulsorily and the compressor 10B stops. Therefore, regardless of whether or not the microcomputer 52 is operating normally, the compressor 10B can be stopped in response to an abnormality in the discharge-side pressure of the compressor 10B, ensuring high reliability. it can.

  Further, the switch response circuit 55 does not cut off the power source for driving the compressor 10B (AC 200 volts in the present embodiment), but is a lower voltage power source (this embodiment) for driving the inverter 53. In the embodiment, it can be easily realized as a circuit for switching DC 5 volts).

  Further, even if the microcomputer 52 does not operate normally due to a bug in the control program of the microcomputer 52, the supply of the inverter drive voltage Vcc to the inverter 53 is stopped, so that the compressor 10B is surely stopped. be able to.

  Further, the switch response circuit 55 is obtained by adding a circuit for turning on / off the supply of the inverter drive voltage Vcc to the inverter 53 to the circuit that outputs the abnormal signal FS to the microcomputer 52 in accordance with the switching operation of the high voltage switch 51A. Yes, by integrating these circuits, an efficient circuit configuration can be achieved, and the cost can be reduced.

In addition, after the high pressure switch 51A is switched off, when the pressure in the pipe where the high pressure switch 51A is disposed falls below the above reference and the high pressure switch 51A returns to the on state, the photocoupler PC1, transistors TR1, TR2 , BRT1 and BRT2 all return to their original states.
For this reason, the supply of the inverter drive voltage Vcc from the switch response circuit 55 to the inverter 53 is also restored, so that the inverter 53 and the compressor 10B are operable.

  In this state, the inverter 53 starts or stops operation according to the control of the microcomputer 52, and therefore does not always automatically restart the operation. For example, the microcomputer 52 uses the inverter 53 based on the time until the abnormal signal FS switches from the high level to the low level, the operating state of each part of the air conditioner 1, the temperature detected in the indoor units 3A, 3B, or the like. Further, by determining whether or not the operation of the compressor 10B should be resumed, optimal abnormality control is performed.

  Even if the microcomputer 52 determines whether the inverter 53 and the compressor 10B are operated or stopped, the supply of the inverter drive voltage Vcc to the inverter 53 is restored. The control by 52 does not cause any trouble.

  Thus, the switch response circuit 55 stops the supply of the inverter drive voltage Vcc to the inverter 53 in response to the OFF operation of the high voltage switch 51A, and prevents the control of the microcomputer 52 when the high voltage switch 51A is restored. As a result, the supply of the inverter drive voltage Vcc is promptly restored.

  The embodiment described above shows one embodiment of the present invention, and it is needless to say that the embodiment can be arbitrarily modified and applied within the scope of the present invention. For example, although the air conditioner 1 of the present embodiment includes the two outdoor units 1A and 1B and the two indoor units 3A and 3B, the present invention is not limited to this, and the outdoor unit The number of indoor units is arbitrary. Further, the functions of the controller 100 and the microcomputer 52 can be realized by a single microcomputer. Furthermore, in the air conditioning apparatus 1 of the present embodiment, the outdoor unit 1A includes the two compressors 10A and 10B, and one of them is the inverter-driven compressor 10B. Can be applied as long as it has at least one inverter-driven compressor and a high-pressure switch is provided on its discharge side piping, and the number of other compressors is arbitrary. Further, the specific mounting mode of the switch response circuit 55 shown in FIG. 3 is arbitrary, an IC (integrated circuit) may be used, and other detailed configurations can be changed as appropriate. .

It is a figure which shows the structure of the air conditioning apparatus which concerns on embodiment of this invention. It is a figure which shows the structure which drives a compressor with an inverter. It is a circuit diagram which shows the specific structural example of a switch response circuit part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Air conditioning apparatus 1A, 1B Outdoor unit 3A, 3B Indoor unit 10A, 10B, 10C Compressor 50 Compressor drive control part 51A High pressure switch (pressure switch)
51B High pressure switch 52 Microcomputer (control means)
53 Inverter 54 Power supply circuit 55 Switch response circuit (Power supply switching circuit)
100 controller

Claims (5)

In an air conditioner equipped with an inverter-driven compressor,
Provided on the power supply line for driving the inverter, and provided with power switching means for cutting the power supply line in conjunction with the switching operation of the pressure switch disposed on the discharge side piping of the compressor An air conditioner characterized by that.   The air conditioner according to claim 1, wherein the pressure switch is a switch that is turned off when a pressure in a discharge side pipe of the compressor exceeds a predetermined pressure. Comprising control means for driving and controlling the inverter;
The air conditioner according to claim 1 or 2, wherein the power supply switching means outputs a control signal to the control means in conjunction with the pressure switch.   The air conditioner according to any one of claims 1 to 3, wherein the power supply switching unit disconnects the power supply line after a predetermined time has elapsed since the pressure switch was switched. The air conditioner according to any one of claims 1 to 4, wherein the power supply switching unit connects the power supply line when the pressure switch is restored.

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