JPH0243995B2 - KUKICHOWASOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a refrigeration cycle and a control device for a separate air conditioner.

[Prior art]

A conventional device of this type is shown in FIG.

During cooling operation, the high-temperature, high-pressure refrigerant and refrigerating machine oil discharged from the compressor 1 pass through the four-way valve 2 and reach the outdoor heat exchanger 3, where they exchange heat and become high-temperature, high-pressure liquid. It passes through the utility 4, is depressurized by the expansion valve 5, passes through the connecting pipe 6, evaporates in the indoor heat exchanger 7, passes through the connecting pipe 8, passes through the four-way valve 2, and the accumulator 9, and is sucked into the compressor 1 again. It forms a circular cycle. Therefore, especially when the compressor 1 is started, the refrigerant that has been trapped in the refrigerating machine oil forms and a large amount of refrigerating machine oil is discharged, and even during continuous operation, a small amount of refrigerating machine oil is continuously discharged, and the discharged refrigerating machine oil The refrigeration oil circulates through the refrigeration cycle and returns to the suction side of the compressor 1, but if the connecting pipes 6 and 8 are particularly long, it takes time for the discharged refrigeration oil to circulate and return. , the amount of refrigerating machine oil in the compressor 1 decreases, resulting in poor lubrication of the compressor and seizure of the sliding parts. In addition, when performing capacity control or operating at low load, the amount of refrigerant circulating decreases and the speed of refrigerant flowing through the pipes decreases, resulting in poor return of refrigerating machine oil, which also causes a defect in the compressor 1. Was. This also applies during heating.

Also, during defrosting, the high temperature, high pressure refrigerant discharged from the compressor 1 passes through the four-way valve 2 and reaches the outdoor heat exchanger 3, where it defrosts, exchanges heat, and becomes a high temperature, high pressure liquid. After passing through the distributor 4, it is depressurized again by the expansion valve 5, and passes through the connecting pipe 6.
A fan on the indoor heat exchanger 7 side (not shown) forms a circulation cycle in which the air is sucked into the compressor 1 again through the indoor heat exchanger 7, the connection pipe 8, the four-way valve 2, and the accumulator 9. When I run it, it blows out cold air, so I try to stop it. Therefore, the low-temperature, low-pressure two-phase flow refrigerant whose pressure is reduced by the expansion valve 5 is not heat exchanged with the indoor heat exchanger 7, so the pressure of the low-pressure gas decreases, and it enters the accumulator 9 as it is, where liquid refrigerant accumulates. Because of this, the refrigerant circulation amount is reduced and the compressor input is also reduced, which has the drawback of prolonging the defrost time.

Furthermore, when the air conditioner is stopped, the refrigerant that had accumulated in the connecting pipe 8 returns to the discharge pipe of the compressor due to its own weight, filling the discharge valve port of the compressor, and when the compressor is started, the refrigerant that has accumulated in the connecting pipe 8 returns to the discharge pipe of the compressor. It had the disadvantage of causing damage.

[Summary of the invention]

This invention was made in order to eliminate the above-mentioned conventional drawbacks, and an oil separator is provided between the discharge side of the compressor and the four-way valve, and the oil separator is connected to the accumulator via a solenoid valve. a first bypass path leading to the accumulator from the oil separator through a capillary tube in parallel with the solenoid valve; It is an object of the present invention to provide an air conditioner that can prevent compressor failure due to lack of refrigerating machine oil by returning a relatively large amount and a relatively small amount through a capillary tube.

[Embodiments of the invention]

Hereinafter, an embodiment of the present invention will be described with reference to FIG. In FIG. 2, the same or corresponding parts as in FIG. 1 are indicated by the same reference numerals. In FIG. 2, 10 is an oil separator, 11 is a first bypass path, 12 is a solenoid valve 13 is a check valve, 14 is a second bypass path, 1
5 is a capillary tube. That is, as shown in FIG. 2, a check valve 13 and an oil separator 10 are arranged in this order between the discharge side of the compressor 1 and the four-way valve 2, and the solenoid valve 12 is connected to the oil separator 10. The oil separator 1
A second bypass path 14 is provided in parallel to the electromagnetic valve 12 from 0 through a capillary tube 15, and a check valve 13 is provided between the discharge side of the compressor 1 and the oil separator 10, so that when the pressures before and after are the same. is closed.

The operation of the present invention will be explained in the above configuration.
In Figure 2, the solid arrows indicate the flow of refrigerant during cooling and defrosting operations, the dashed arrows indicate the flow of refrigerant during heating, and the dashed-dotted line indicates the flow of refrigerant and refrigerating machine oil in the bypass path. It is.

During cooling, high-temperature, high-pressure refrigerant and refrigerating machine oil discharged from the compressor 1 pass through the check valve 13 and enter the oil separator 1.
The refrigerating machine oil that enters from the top of the oil separator 10 is separated and collected at the bottom of the oil separator 10. The gaseous refrigerant separated from the refrigeration oil exits from the upper part of the oil separator 10, reaches the four-way valve 2, and the outdoor heat exchanger 3, where it exchanges heat and becomes a high-temperature, high-pressure liquid, which is then sent to the distributor 4. Thereafter, the pressure is reduced by the expansion valve 5, and the gas passes through the connecting pipe 6, is evaporated in the indoor heat exchanger 7, and returns to the compressor 1 via the connecting pipe 8, the four-way valve 2, and the accumulator 9.
During this operation, refrigerating machine oil corresponding to the amount of refrigerating machine oil discharged from the compressor 1 is constantly returned to the accumulator 9 via the second bypass passage 14 from the capillary tube 15 located in the middle of the second bypass passage 14, and Although the solenoid valve 12 located in the middle of the passage 11 is closed, a larger amount of refrigerating machine oil is discharged from the compressor 1 than the refrigerating machine oil flowing through the second bypass passage 14. When the oil accumulates in the separator, the solenoid valve 12 is opened by a signal, and the refrigerating machine oil accumulated in the lower part of the oil separator 0 is returned to the accumulator 9 via the bypass path 11 and the solenoid valve 12, and is returned to the indoor side. The low-temperature, low-pressure gas returned by the heat exchanger 7 returns to the compressor 1, and the refrigerating machine oil circulation circuit is greatly shortened. The same applies to heating.

Therefore, even when the distance between the indoor unit and the indoor unit is large, that is, when the connecting pipes 6 and 8 are long, the refrigerating machine oil circulation circuit is a short bypass circuit, so the refrigerating machine oil in the compressor 1 is Even if a large amount of refrigerating machine oil is discharged due to operating conditions, a large amount of refrigerating machine oil is quickly returned to the short second bypass path 14 via the solenoid valve 12, so that the compressor 1 can be refrigerated. There will be no oil shortage.

In addition, when the compressor 1 is of the capacity control type, the circulating amount of refrigerant discharged from the compressor is greatly reduced. The distance of the circuit through which machine oil circulates does not change, and because it is short, there is no possibility of insufficient return of refrigeration machine oil. Furthermore, by keeping the electromagnetic valve 12 open when the compressor 1 is started, and keeping it open for a certain period of time (for example, 1 minute) after the start, the refrigerant lying in the refrigerating machine oil when the compressor 1 is stopped is caused to form when the compressor is started. Although a large amount of refrigerating machine oil is discharged from the compressor 1 compared to normal continuous operation, only the refrigerating machine oil is separated by the oil separator, and it does not circulate through the refrigerant circuit, so that it can be used only in the second bypass passage 14 with a small flow rate. In addition, the solenoid valve 1 which is open via the first bypass path 11 with a large flow rate
2, it returns to the accumulator 9 and returns to the compressor 1 together with the low-pressure gas, making it possible to compensate for the shortage of refrigerating machine oil in a short time.

Furthermore, when switching from heating operation to defrost operation,
The four-way valve 2 is switched and the high temperature, high pressure refrigerant gas compressed by the compressor 1 is passed through the check valve 13 and the oil separator 10.
After that, defrost is carried out in the outdoor heat exchanger 3 by the four-way valve 2, the pressure is reduced by the expansion valve 5 through the distributor 4, the connection pipe 6, the indoor heat exchanger 7, and the connection pipe 8. After that, it is returned to the four-way valve 2 and the accumulator 9 again. Compressor 1 at the same time
The high-temperature, high-pressure gas exiting from the oil separator 10 is passed through the bypass circuit 11 and the solenoid valve 12.
It is returned into the accumulator 9. In the accumulator 9, the low-temperature, low-pressure refrigerant gas that has passed through the evaporator 7 is mixed with the high-temperature, high-pressure refrigerant gas that has passed through the bypass path 11, so the pressure of the low-pressure gas is increased and compressed. Return to aircraft 1. As a result, it becomes possible to create a state where the specific volume is small and the circulation amount is large, and the frost formed on the outdoor heat exchanger 3 can be defrosted in a short time.

In addition, when heating is at low temperatures, there is a risk of frost forming quickly, so the solenoid valve 12 is opened again and the bypass passage 11 is opened, and a portion of the discharged gas bypasses the accumulator 9, thereby preventing heating at low temperatures. Capacity can be increased.

Furthermore, during the defrosting and heating at low temperatures mentioned above, by using a variable capacity compressor and operating the compressor 1 at its maximum capacity when the solenoid valve 12 is opened, the defrosting and heating capacities are even more effective. is obtained.

Furthermore, during cooling or heating, by opening the solenoid valve 12 after a certain continuous operating time (for example, 60 minutes) after starting the compressor 1, the second Bypass path 14
A bypass passage 11 is opened from the oil separator 10 in which a larger amount of refrigerating machine oil than the amount returned to the accumulator 9 is discharged from the compressor 1, separated and accumulated, and the oil is returned to the accumulator 9 via the solenoid valve 12.
It returns to the compressor 1 together with the low-temperature, low-pressure gas returned from the evaporator, making it possible to replenish the refrigerating machine oil.

Also, because of this configuration, when the air conditioner is stopped, even if the refrigerant that had accumulated in the connection pipe 8 returns to the discharge pipe of the compressor due to its own weight, it will be accumulated in the oil separator 10 and then transferred to the oil separator 10. By closing the check valve 13 located between the check valve 10 and the discharge side of the compressor, it is possible to prevent refrigerant and refrigeration oil from entering the inside of the discharge side of the compressor, which also has the effect of preventing valve damage when starting the compressor. have. The effect will be further improved if the check valve 13 is installed in such a way that the check valve closes when the pressures before and after the check valve 13 are balanced.

In the above embodiment, a split type compressor was used with the compressor located outside the room, but a remote type compressor with the compressor located inside the room may also be used.Although an expansion valve was used as the throttle device, a capillary tube or electric It may be a type expansion valve or an orifice, and it may be installed at any position between the indoor heat exchanger and the outdoor heat exchanger.

〔Effect of the invention〕

As described above, according to the present invention, the oil separator 10 is provided between the discharge side of the compressor 1 and the four-way valve 2, and the oil separator reaches the accumulator 9 via the solenoid valve 12. A first bypass path 11 is provided, and a second bypass path 11 is provided which is connected to the solenoid valve 12 by the oil separator 10 and connected to the accumulator 9 via a capillary tube 15.
Since a bypass path 14 is provided to return the refrigerating machine oil and hot gas to the accumulator 9, the installation distance between the indoor side and the outdoor side (connecting pipes 6 and 8) can be easily made extremely long, and the capacity can be varied. Even if the amount of refrigerant discharged by the compressor etc. decreases significantly, the refrigerating machine oil can easily return to the compressor.
Furthermore, since the flow rate of the first bypass path 11 is made larger than the flow rate of the second bypass path 14, even if the discharge amount of the refrigerator increases, the solenoid valve 12 is opened and the compressor is quickly operated by the first bypass path 11. 1, it is possible to reduce the flow rate of the second bypass path, which is always open via the capillary tube 15, to prevent a decrease in capacity during normal operation, and the refrigerating machine oil is constantly supplied to the compressor. You can also return it.

[Brief explanation of drawings]

FIG. 1 is a diagram illustrating a conventional refrigeration cycle, and FIG. 2 is a diagram illustrating a refrigeration cycle showing an embodiment of the present invention. 1 is a compressor, 2 is a four-way valve, 3 is an outdoor heat exchanger, 4 is a distributor, 5 is an expansion valve, 6
is a connection pipe, 7 is an indoor heat exchanger, 8 is a connection pipe, 9 is an accumulator, 10 is an oil separator,
11 is the first bypass path, 12 is the electromagnetic valve, 13 is the check valve, 14 is the second bypass path, 15 is the capillary tube, solid arrows represent the refrigerant flow during cooling and defrost operation, and broken arrows represent the heating flow. It represents the flow of refrigerant during operation, and the dashed line represents the flow of refrigerant and refrigerating machine oil in the bypass path. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Claims] 1 Compressor, 4-way valve, outdoor heat exchanger, throttling device,
In an air conditioner formed by connecting an indoor heat exchanger and an accumulator in a ring to form a circulation cycle, the oil separator is provided between the discharge side of the compressor and the four-way valve, and the oil separator. a first bypass path leading from the oil separator to the accumulator via a solenoid valve, and a second bypass path running from the oil separator to the aggregator via a capillary tube in parallel with the solenoid valve, the flow rate being lower than the flow rate of the second bypass path. A separate air conditioner characterized in that the flow rate of the first bypass path is set to be larger than that of the first bypass path.