JPS6337866B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application 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.

BACKGROUND ART In recent years, multi-room air conditioners have become increasingly low-noise and low-vibration.

Hereinafter, an example of the refrigeration cycle of the conventional multi-room air conditioner mentioned above will be described with reference to the drawings.

FIG. 4 is a refrigeration cycle diagram of a conventional multi-room air conditioner. In Fig. 4, outdoor unit 1
The compressor 2, the four-way valve 3, the heat source side heat exchanger 4, the liquid side main pipe 5, and the indoor unit 6a from the liquid side main pipe 5,
Liquid side branch pipes 7a, 7 formed by branching as many as 6b
b, gas side main pipe 8, gas side branch pipes 9a, 9b branched from the gas side main pipe 8 by the number of indoor units 6a, 6b, heating throttle device 10 provided in the liquid side main pipe 5, and this heating A check valve 11 connected in parallel with the throttle device 10 to block the flow of refrigerant during heating operation, a cooling throttle device 12 connected in series to these, and a solenoid valve 13a provided in each liquid side branch pipe 7a, 7b. , 13b, each gas side branch pipe 9a,
Solenoid valves 14a and 14b provided in 9b, check valve 15 with the low pressure circuit side as the flow blocking side during heating operation
a, 15b and throttle devices 16a, 16b are connected in series, and the solenoid valves 13a, 13 are connected in series.
It consists of bypass pipes 17a and 17b that connect liquid side branch pipes 7a and 7b between the connection ports of indoor units 6a and 6b to the low pressure circuit during heating. In addition, the indoor units 6a and 6b have indoor heat exchangers 18a and 18b, respectively.
18b, the liquid side branch pipe 7 of the outdoor unit 1
a, 7b, gas side branch pipes 9a, 9b, liquid side pipes 19a, 19b, gas side pipes 20a, 20b, respectively.
connected with.

The operation of the refrigeration cycle of the multi-room air conditioner configured as described above will be described below.

First, when the indoor unit 6a is in heating operation, that is, the refrigerant discharged from the compressor 2 passes through the four-way valve 3, the gas side main pipe 8, the gas side branch pipe 9a, the solenoid valve 14a, and the gas side pipe 20a. It enters the unit 6a, is liquefied for heating in the indoor heat exchanger 18a, returns to the outdoor unit 1 through the liquid side pipe 19a, and is passed through the liquid side branch pipe 7a, the solenoid valve 13a, the liquid side main pipe 5 to the cooling throttle device 12. Heating diaphragm device 1
It is depressurized at 0, absorbs heat in the heat source side heat exchanger 4, and returns to the compressor 2 through the four-way valve 3. When the other indoor unit 6b is additionally operated, the solenoid valves 13b and 14b
was opened and heating was performed by the indoor heat exchanger 18b.

Problems to be Solved by the Invention However, in the conventional configuration as described above,
In the indoor heat exchanger 18b of the indoor unit 6b subjected to this additional heating operation, before the heating operation was started, the flow of refrigerant had been stopped by closing the solenoid valves 13b and 14b at the entrance and exit, and the refrigerant was under low pressure. Since the compressor was connected to the connected circuit through the bypass pipe 17b, the pressure was at a low pressure almost the same as the suction pressure of the compressor 2. Therefore, the solenoid valve 13 at the entrance and exit
b and 14b at the same time, high-pressure gas will flow into the low-pressure indoor heat exchanger 18b at high speed, and this flowing refrigerant may generate a very loud impact noise or cause the pilot valves of the solenoid valves 13b and 14b to By rapidly moving the
It also makes a "clicking" sound. These impact noises and lunchbox noises are amplified by the indoor unit 6b, causing a serious problem in that they generate large noises and vibrations from the floor and walls on which the indoor unit 6b is installed.

The present invention solves the above conventional problems,
The object of the present invention is to provide a refrigeration cycle for a multi-room air conditioner that can achieve low noise and vibration.

Means for Solving the Problems In order to solve the above problems, the refrigeration cycle of the multi-room air conditioner of the present invention is a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit by connecting piping. In the air conditioner, a solenoid valve is provided in a gas side branch pipe branched from the gas side main pipe of the outdoor unit by the number of indoor units and connected to each of the indoor units, and also connected to the liquid side main pipe of the outdoor unit. A solenoid valve is provided in the liquid side branch pipe which is branched from the same number of indoor units as the number of indoor units and is connected to each of the indoor units, and a circuit from the gas side main pipe or the gas side main pipe to the solenoid valve in each gas side branch pipe. A bypass pipe is provided between the circuit from each indoor unit to each solenoid valve in each liquid side branch pipe, and a solenoid valve and a throttle device are connected in series in each of the bypass pipes. Liquid drain bypass pipes are installed between the circuits from the unit to each solenoid valve in each liquid side branch pipe and the pipe line that is at low pressure during heating operation, and the solenoid valves installed in the bypass pipes are operated at a certain level during heating operation. The valve is opened until time or the pressure of the indoor unit reaches a certain value, and then the solenoid valve provided in the gas side branch pipe and the solenoid valve provided in the liquid side branch pipe are opened.

Effects According to the present invention, with the above-described configuration, an indoor unit that performs additional heating operation first opens the solenoid valve for the bypass pipe connected to the high-pressure gas circuit, reduces the pressure of the high-pressure gas refrigerant with the throttle device, and then The internal pressure of the indoor heat exchanger is increased by flowing into the indoor heat exchanger which is at low pressure, and then the solenoid valve in the original gas side branch pipe and the solenoid valve in the liquid side branch pipe are opened. Since the refrigerant does not have much pressure difference, impact noise, lunchbox noise, and vibration can be drastically reduced.

Embodiment Hereinafter, a refrigeration cycle for a multi-room air conditioner showing an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a refrigeration cycle diagram of a multi-room air conditioner showing one embodiment of the present invention. In Figure 1,
The outdoor unit 31 includes a compressor 32, a four-way valve 33,
Heat source side heat exchanger 34, liquid side main pipe 35, liquid side branch pipes 37a, 37b formed by branching from the liquid side main pipe 35 by the number of indoor units 36a, 36b, gas side main pipe 38, from the gas side main pipe 38 to the indoor unit. unit 3
Gas side branch pipes 39a, 39b formed by branching as many as 6a, 36b, a heating throttle device 40 provided in the liquid side main pipe 35, and this heating throttle device 4
A check valve 41 that is connected in parallel with 0 to block the flow of refrigerant during heating operation, a cooling throttle device 42 connected in series to these, and each liquid side branch pipe 37a, 3
Solenoid valves 43a, 43b provided in each gas side branch pipe 39a, 39b, and solenoid valves 44a, 4 provided in each gas side branch pipe 39a, 39b.
4b, check valves 45a, 45b with the low pressure circuit side as the flow blocking side during heating operation, and a throttle device 46a,
46b are connected in series, and the solenoid valves 43a, 43b and each indoor unit 36a, 36b are connected via the solenoid valves 43a, 43b in series.
Bypass pipes 47a, 47b connecting the liquid side branch pipes 37a, 37b between the connection ports to the low pressure circuit during heating, throttle devices 48a, 48b, and solenoid valves 49a, 49b
are connected in series, and the solenoid valve 43 is connected through this.
The liquid side branch pipes 37a, 37b between the connection ports of a, 43b and each indoor unit 36a, 36b are connected to the gas side main pipe 38 or the gas side main pipe 38 which becomes the high pressure gas for heating operation.
Solenoid valve 44 in each gas side branch pipe 39a, 39b
Bypass pipe 50a connected to the circuit up to a and 44b,
It is more familiar than 50b. In addition, the indoor unit 36
a and 36b are indoor heat exchangers 51a and 5, respectively.
1b, the liquid side branch pipe 37 of the outdoor unit 31
a, 37b, gas side branch pipes 39a, 39b, liquid side pipes 52a, 52b, gas side pipe 53a,
53b.

FIG. 2 shows an example of an electric circuit, in which a solenoid valve 4
Coil 43a' of 3a and coil 44 of solenoid valve 44a
a' and the relay coil 32a are the operation switch 54a and relay contact 55 of the indoor unit 36a, respectively.
Similarly, the coil 43 of the solenoid valve 43b is connected in parallel to the power supply 56 via a series-connected circuit.
b', the coil 44b' of the solenoid valve 44b, and the relay coil 32b are connected in parallel to a power source 56 via a circuit in which the operation switch 54b of the indoor unit 36b and the relay contact 55b are connected in series, respectively, and the motor 32 of the compressor 32 are relay contacts 32a', 32
b' is connected to a power source 56 via a circuit in which the terminals b' are connected in parallel. Furthermore, a circuit is connected in series with the relay contacts 57a, 57b and the coils 49a', 49b' of the solenoid valves 49a, 49b, respectively, the coil 33' of the four-way valve 33, a microcomputer, etc., and operation switches 54a, 54b are turned on and off. By detecting the relay contacts 55a, 55b, 57a,
A control device 58 that controls the heating/cooling switch 57b is connected in parallel to the power source 56 via the heating side contact 60 of the cooling/heating changeover switch 59.

The operation of the multi-room air conditioner in the above configuration during heating operation will be explained. Now, the cooling/heating switch 5
If the operation switch 54a of the indoor unit 36a is turned on while the heating side contact 60 is turned on, the control device 58 including a microcomputer or the like will turn on the motor 32' of the compressor 32 that the indoor unit 36a has stopped. It is detected that the first signal for rotation is issued, and in order to keep the relay contact 55a closed, voltage is applied to the coils 43a', 44a' of the solenoid valves 43a, 44a and the relay coil 32a, and the solenoid valves 43a, 44a are turned on. The refrigerant passage 44a is opened, the relay contact 32a' of the relay coil 32a is closed, and the motor 32' of the compressor 32 is rotated.
At this time, as mentioned earlier, the control device 58 detects that the indoor unit 36a has issued the first control signal to rotate the motor 32' of the stopped compressor 32, so it closes the relay contact 57a. Bypass solenoid valve 49 to keep it open
The coil 49a' of a is not energized. Since the coil 33' of the four-way valve 33 is energized in this way,
The refrigerant discharged from the compressor 32 passes through the four-way valve 33, the gas side main pipe 38, the solenoid valve 44a, the gas side branch pipe 39a, and the gas side pipe 53a to the indoor unit 3.
It radiates heat and liquefies in the indoor heat exchanger 51a of 6a,
Liquid side pipe 52a, liquid side branch pipe 37a, solenoid valve 43
a. It passes through the liquid side main pipe 35, is depressurized by the heating throttle device 40, passes through the heating low pressure circuit, absorbs heat in the heat source side heat exchanger 34, evaporates, and returns to the compressor 32 through the four-way valve 33 again. forming a series of refrigeration cycles,
The indoor unit 36a performs heating operation.

Further, when the indoor unit 36a is in the heating operation, the other indoor unit 36b opens the contact point of the operation switch 54b, so the heating operation is not performed, and the coils 43b', 44 of the solenoid valves 43b, 44b are not in operation.
b' is not energized, so solenoid valves 43b and 44
b closes the refrigerant passage. Therefore, solenoid valve 4
The refrigerant does not flow into the refrigeration circuit including the indoor heat exchanger 51b, which is closed by the solenoid valve 3b and the solenoid valve 44b. However, in reality, the solenoid valves 43a, 4
3b, 44a, 44b, etc. cannot completely stop the flow of refrigerant and there is some leakage, so refrigerant will accumulate little by little in the indoor heat exchanger 51b of the indoor unit 36b that is stopped. . Therefore, the refrigerant accumulated in the indoor heat exchanger 51b is extracted by a bypass pipe 47b whose one end is connected to a low-pressure circuit during heating operation. Therefore, the indoor heat exchanger 51 of the indoor unit 36b that is stopped
The refrigerant pressure in b is in the same pressure state as the low pressure circuit during heating operation.

Under these circumstances, other indoor units 3
6b, when the operation switch 54b of the indoor unit 36b is turned on, as shown in the valve operation timing chart in FIG. , it is detected that the operation switch 54b is turned on while the motor 32' of the compressor 32 is in operation, and the relay contact 55b is activated.
When the relay contact 57b is closed, voltage is applied to the coil 49b' of the solenoid valve 49b for the bypass pipe 50b, and the solenoid valve 49b is opened. It is communicated with the indoor heat exchanger 51b of the indoor unit 36b. The high-pressure gas refrigerant is then depressurized by the expansion device 48b to reduce the pressure difference and flows into the indoor heat exchanger 51b.
Increase the refrigerant pressure of 1b. Gas refrigerant has a high velocity, but because it is under reduced pressure, there is no impact noise. In this way, the indoor heat exchanger 51b in the indoor unit 36b
When the internal pressure rises to a certain extent and the solenoid valve 44b is opened, the control device 58 consisting of a microcomputer etc. detects a point where there is not much difference in pressure from the pressure of the refrigerant flowing into the indoor heat exchanger 51b, and this control device 58 opens the relay contact 57b, closes the relay contact 55b, closes the solenoid valve 49b for the bypass pipe 50b, and opens the original solenoid valves 43b and 44b. At this time, the refrigerant flowing through the solenoid valve 44b enters the indoor heat exchanger 51b with a small pressure difference, so that no impact noise, vibration noise, or valve hitting noise is generated. Further, since the solenoid valve 44b does not undergo sudden valve punching, the valve will not be damaged. Also indoor unit 36
The pressure of the indoor heat exchanger 51b of b is controlled by the solenoid valve 43b.
Since it remains closed, the heating time is quick and short, and therefore no time is required for the original heating operation such as blowing out hot air.

Furthermore, in the electric circuit shown in FIG. 2, temperature regulators are provided in series with the operating switches 54a and 54b, and similar control is applied when other indoor units are operated and the temperature regulator returns while the compressor is operating. You can get exactly the same effect by doing this. Further, the opening time of the bypass electromagnetic valves 49a and 49b may be calculated and determined each time by a microcomputer or the like, taking various conditions into consideration. That is, the various conditions include various factors such as the number of units in the operating room, temperature controller setting temperature, and temperature controller OFF time. Further, the bypass solenoid valve may be controlled by a pressure switch or the like.

Effects of the Invention As described above, according to the present invention, when the compressor is running and at least one indoor unit is in heating operation, when the other indoor unit is restarted by additional heating operation or by using a temperature controller, etc., the gas side After bypassing medium-pressure refrigerant from the main branch pipe to the liquid side branch pipe between the liquid side solenoid valve and the indoor unit and increasing the pressure in the indoor heat exchanger of the indoor unit, the gas side solenoid valve Since the solenoid valve on the gas side can be opened, it is possible to achieve low-noise and low-vibration heating operation with no refrigerant impact noise or vibration from the indoor unit, and there is no strong gas-side solenoid valve punching noise. This has great effects such as significantly extending the life of the solenoid valve.

[Brief explanation of the drawing]

FIG. 1 is a refrigeration cycle diagram of an embodiment of a multi-room air conditioner according to the present invention, FIG. 2 is an electric circuit diagram thereof, and FIG. 3 is an operation timing chart of a solenoid valve.
FIG. 4 is a refrigeration cycle diagram of a conventional multi-room air conditioner. 31...Outdoor unit, 34...Heat source side heat exchanger, 35...Liquid side main pipe, 36a, 36b...Indoor unit, 37a, 37b...Liquid side branch pipe, 38...
...Gas side main pipe, 39a, 39b...Gas side branch pipe,
43a, 43b, 44a, 44b...Solenoid valve, 4
5a, 45b... Check valve, 46a, 46b... Throttle device, 47a, 47b, 50a, 50b... Bypass pipe, 48a, 48b... Throttle device, 49
a, 49b...Solenoid valve, 51a, 51b...Indoor heat exchanger, 54a, 54b...Indoor unit operation switch, 58...Control device, 59...Cooling/heating changeover switch.

Claims (1)

[Claims] 1. In a multi-room air conditioner in which a plurality of indoor units are connected to one outdoor unit by connecting piping, the gas side main pipe of the outdoor unit is branched as many times as the number of indoor units, and the pipe is connected to each of the indoor units. A solenoid valve is provided in the gas side branch pipe to be connected, and a solenoid valve is also provided in the liquid side branch pipe that is branched from the liquid side main pipe of the outdoor unit by the number of the indoor units and connected to each of the indoor units. , a bypass pipe is provided between the circuit from the gas side main pipe or the gas side main pipe to the solenoid valve in each gas side branch pipe and the circuit from each of the indoor units to each solenoid valve in each liquid side branch pipe; A solenoid valve and a throttling device are connected in series in each bypass pipe, and a liquid is connected between the circuit from each indoor unit to each solenoid valve in each liquid-side branch pipe and the pipe that is at low pressure during heating operation. Install a bypass pipe,
During the heating operation, the solenoid valve provided in the bypass pipe is opened for a certain period of time or until the pressure in the indoor unit reaches a certain value, and then the solenoid valve provided in the gas side branch pipe and the solenoid valve provided in the liquid side branch pipe are opened. A refrigeration cycle for a multi-room air conditioner configured to open a solenoid valve.