JPS6235023B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a so-called multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit. One of the purposes is to greatly reduce the pressure difference between high and low pressures in a short period of time, and to enable the pole change type compressor to be restarted quickly.

Conventionally, multi-room air conditioners have been known to use a pole change type compressor, but when changing the number of poles of a pole change type compressor during operation, the poles change instantly. I was switching numbers. However, for example, if a pole converter compressor with a 2-pole motor and a 4-pole motor has no slippage during 60 cycles, the rotation speed of the 2-pole motor will be 3600 revolutions per minute.
The rotation speed of a 4-pole motor is 1800 revolutions per minute, so the rotation speed of a motor that instantly switches from a 4-pole motor to a 2-pole motor, or from a 2-pole motor to a 4-pole motor, instantly doubles. or halved.

Such a rapid change in rotational speed causes a sudden change in the force applied to the compressor mechanism of the pole change type compressor, which has the disadvantage of easily damaging the compressor mechanism. In particular, a rapid reduction in rotational speed by half applies reverse torque to the compressor crankshaft and generates a back electromotive force in the motor, which has the major drawback of damaging the crankshaft and damaging the motor.

Therefore, in order to protect the pole change type compressor from damage, the present invention has been developed so that when the compressor is temporarily stopped when changing the number of poles, not only the solenoid valve in the bypass pipe but also the solenoid valve in the pipe connected to the indoor unit The number of poles can be changed in as short a time as possible by operating a valve.

Hereinafter, the present invention will be described with reference to the accompanying drawings showing one embodiment thereof.

In Fig. 1, reference numeral 1 denotes an outdoor unit, which includes a pole converter compressor 2 equipped with a two-pole motor _C2 and a four-pole motor _C4 , which will be described later, a discharge muffler 3, a heat source side heat exchanger 4, and a liquid receiving unit. 5, a main liquid side pipe 6, and a plurality of liquid side branch pipes 7a, 7b, 7 branched from the main liquid side pipe 6.
c. Solenoid valves 8 which are provided in the liquid side branch pipes 7a, 7b, and 7c and which open the passages when energized.
a, 8b, 8c, the liquid side branch pipes 7a, 7b, 7c
Sealing connection ports 9a, 9b, 9c provided at the connections with the indoor units 20a, 20b, 20c, gas side branch pipes 11a, 11b branching from the gas side main pipe 13,
11c, this gas side branch pipe 11a, 11b, 11c
connection ports 10a, 10b, 10c provided at the connections with the indoor units 20a, 20b, 20c, a shutoff valve 12 provided in the gas side branch pipe 13, an accumulator 14, a solenoid valve 1 that closes the passage when energized.
6 and are each provided with a bypass pipe 15 connecting the liquid side main pipe 6 and the gas side main pipe 13. In addition, each indoor unit 20a, 20b, 20c has a user side heat exchanger 21a, 21b, 21, respectively.
c, and diaphragm devices 22a, 22b, and 22c.

Next, the electric circuit of this embodiment will be explained based on FIG. 2.

In the same figure, 30a, 30b, 30c are provided in the liquid side branch pipes 7a, 7b, 7c, respectively, and are electromagnetic valves 8a, 8 of the type that open passages when energized.
Coils b and 8c, 31 are coils of a solenoid valve 16 that is provided in the bypass pipe 15 and closes the passage when energized, and C ₄ and C ₂ each constitute a coil 32 of the pole change type compressor 2. 4-pole coil and 2
The coils 38a, 38b, 3 are each connected as a load to an electronic control device 45 composed of a microcomputer, etc.
Relay 33a with 8c, 40, 42, 44,
Opening/closing contacts 3 of 33b, 33c, 34, 35, 36
7a, 37c, 39, 41, and 43, respectively. Further, the coils 30a, 30b, 3
0c, 31, and 32 are each connected to a power source 46, and the electronic control unit 45 is connected to a power source 47, respectively.

In the above configuration, the operation will be explained next. Assume that the two indoor units 20a and 20b are now in operation, and that the pole change type compressor 2 is in operation with the four-pole coil _C4 energized. Here, the refrigerant gas discharged from the pole change type compressor 2 passes through the discharge muffler 3 and is liquefied in the heat source side heat exchanger 4, and is liquefied in the liquid receiver 5, the liquid side main pipe 6, and the liquid side branch pipes 7a and 7b. Coils 30a, 30
The solenoid valves 8a, 8 are energized and the passage is open.
b, sealed connection ports 9a, 9b, indoor unit 20
After passing through the expansion devices 22a and 22b of the a and 20b, it evaporates into a gaseous state in the heat exchangers 21a and 21b on the usage side, and then flows through the connection ports 10a and 10b and the gas side branch pipe 11.
a, 11b, the gas side main pipe 13, the blockade valve 12, and the accumulator 14 to the pole change type compressor 2 again.
Return to Here, while the pole change type compressor is in operation, the coil 31 of the solenoid valve 16 in the bypass pipe 15 is energized, so the passage is closed. Therefore, the refrigerant does not flow through the bypass pipe 15. Furthermore, since the indoor unit is not in operation, the coil 30c of the solenoid valve 8c is not energized and the refrigerant does not pass through the indoor unit 20c. Under these operating conditions, as the room temperature begins to rise, the indoor units 20a and 20b are required to have even greater capacity, and the two-pole coil C2 has a higher capacity than the four-pole coil _{C4 .} Suppose that it becomes necessary to switch to operation.

Here, according to FIG. 3, the coils 30a, 30b,
30c, 31, and 2-pole and 4-pole coil C ₄ ,
The switching operation of _C2 will be explained.

Until this time T ₁ , the coils 3 of relays 33a, 33b, 34, and 35 are controlled by the electronic control device 45.
8a, 38b, 40, 42 are energized and the opening/closing contact 3
7a, 37b, 39, 41 are closed, solenoid valves 8a,
The coils 30a, 30b, 31 of the coils 8b and 16 and the four-pole coil _C4 of the pole change type compressor 2 are energized. As mentioned earlier, it became necessary to switch to two-pole coil operation in response to the request for increased capacity, so at time T ₁ , the electronic control unit 45 controls the energization of the coils 40 and 42 of the relays 34 and 35. It is cut off, the switching contacts 39 and 41 open, and the energization to the coil 31 of the solenoid valve 16 and the 4-pole coil C ₄ of the pole converter compressor 2 is stopped. As a result, the pole change type compressor 2 stops operating, and the solenoid valve 16 opens its passage, and the refrigerant flows through the bypass pipe 15 from the high pressure side liquid side main pipe 6 to the low pressure side gas side main pipe 3. The pressure on the low pressure side and the low pressure side try to balance. However, since it takes time for the pressure to be completely balanced only by using the bypass pipe 15, restarting the pole change type compressor 2 is performed within a short time after the pole number change type compressor 2 is stopped. If this is not possible, the room temperature in the room where the indoor units 20a and 20b are installed will rise. Therefore, at time _T1 , relay 33 is activated under the control of electronic control device 45.
The coils 30a, 30 of the solenoid valves 8a, 8b do not stop energizing the coils 38a, 38b of the solenoid valves 8a, 8b.
By energizing B and keeping the passages of the solenoid valves 8a and 8b open, not only the bypass pipe 15 but also the liquid side branch pipe 7a, the solenoid valve 8a, and the indoor unit 2
0a, a circuit consisting of the gas side branch pipe 11a, a circuit consisting of the liquid side branch pipe 7b, the solenoid valve 8b, the indoor unit 20b, and the gas side branch pipe 11b can be used to promote pressure equilibrium between the high pressure side and the low pressure side. The time it takes for the number conversion compressor 2 to reach a pressure difference that allows it to be restarted becomes extremely short.

Then, at time T ₂ when the pressure difference reaches such a level that this restart is possible, the electronic control unit 45 controls the coils 40 and 44 of the relays 34 and 36 to energize, close the on/off contacts 39 and 43, and close the coils of the solenoid valve 16. 31 to close the passage of the solenoid valve 16, and energize the two-pole coil C2 of the pole change type compressor ₂ to perform two-pole operation. Further, these operations are exactly the same when switching from two poles to four poles.

It is most desirable for air conditioning to be able to change the number of poles instantaneously in this way, but if the number of poles is changed continuously, there is a high possibility that the compressor will be destroyed, so it is necessary to stop the compressor once. It is necessary.
Therefore, once it becomes necessary to stop the air conditioner, it is desirable that this time be as short as possible without damaging the air conditioning, and this embodiment satisfies this condition.

As is clear from the above embodiments, the multi-room air conditioner of the present invention balances the pressure by using a circuit including a bypass pipe and each indoor unit when the pole number change type compressor is once stopped for pole number switching. In order to facilitate this, the pole switching type compressor can be restarted in an extremely short time, and the solenoid valve in the liquid side branch pipe, which is in communication even before the compressor stops, can restart the compressor. Since the refrigerant continues to be opened until the temperature is reached, the refrigerant will not be trapped inside the heat exchanger on the user side. As a result, the amount of refrigerant circulation can be ensured when restarting.
Ability to get a good start-up is obtained. In addition, the solenoid valve in the liquid side branch pipe of the user heat exchanger that is not in use remains closed, so refrigerant does not flow in to balance the pressure, and noise may be emitted into the room that is not in use. do not have. Therefore, the indoor environment when not in use will not be made uncomfortable. This can extend the life of the compressor. Furthermore, since the refrigerant flowing through the bypass pipe is a liquid refrigerant with low flow resistance, it flows easily and the time required for pressure equilibrium is further shortened. The conversion type compressor can be restarted without compromising comfort.

[Brief explanation of the drawing]

Fig. 1 is a refrigeration cycle diagram of a multi-room air conditioner according to an embodiment of the present invention, Fig. 2 is an electric circuit diagram of the multi-room air conditioner, and Fig. 3 is a diagram of each solenoid valve in the air conditioner. FIG. 3 is a timing chart showing open and closed states. 2...Pole change type compressor, 4...Heat source side heat exchanger, 8a, 8b, 8c...Solenoid valve, 20a, 20
b, 20c...indoor unit, 33a, 33b,
33c, 34, 35, 36... Relay (control circuit), 45... Control device (control circuit).

Claims (1)

[Claims] 1. A plurality of indoor units are connected to one outdoor unit, and a pole change type compressor is provided as a compressor constituting a refrigeration cycle, and the compressor is branched from the liquid side main pipe of the outdoor unit in the refrigeration cycle and connected to the indoor unit. A solenoid valve is provided in each of the plurality of liquid-side branch pipes, the number of which is equal to the number of the indoor units, and a bypass solenoid valve is further provided between the gas-side main pipe and the liquid-side main pipe where the plurality of gas-side branch pipes, the number of which is the number of the indoor units, join together. a pole number switching switch that temporarily stops the pole number changing type compressor when changing the number of poles of the pole number changing type compressor; a bypass solenoid valve switch that opens the valve; and a solenoid valve that continuously keeps the solenoid valve in the liquid side branch pipe connected to the indoor unit from before the pole number changeover of the pole number converting compressor is open. A multi-room air conditioner equipped with a switch.