JPH048702B2 - - Google Patents

Description

Detailed Description of the Invention The present invention provides an air conditioner in which a compressor, a four-way valve, an outdoor heat exchanger, a throttling device, an indoor heat exchanger, and an accumulator are sequentially connected in a ring through piping to form a circulation cycle. It is related to.

A conventional air conditioner 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, which is then sent to the distribution unit. The circulating air is depressurized by an expansion valve 5, passed through a connecting pipe 6, evaporated in an indoor heat exchanger 7, passed through a connecting pipe 8, passed through a four-way valve 2, an accumulator 9, and is sucked into the compressor 1 again. forming a cycle.

Therefore, particularly when the compressor 1 is started up, the refrigerant trapped in the refrigerating machine oil undergoes forming, and a large amount of the refrigerating machine oil is discharged, and the refrigerating machine oil is constantly discharged during continuous operation.

The discharged 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, the discharged refrigeration oil circulates and returns. This takes time, and the amount of refrigerating machine oil in the compressor 1 decreases, resulting in poor lubrication of the compressor and seizure defects on the sliding parts. In addition, if the refrigerant circulation rate decreases during capacity control or low-load operation, and the refrigerant speed flowing through the pipes decreases, the refrigerant oil returns poorly, which also causes a defect in the compressor 1. Was. This also applies during heating.

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. A circulation cycle is started in which the pressure is reduced through the distributor 4, the expansion valve 5, the connection pipe 6, the indoor heat exchanger 7, the connection pipe 8, the four-way valve 2, and the accumulator 9, and then the air is sucked into the compressor 1 again. Form. In this case, the indoor heat exchanger 7
The side fans (not shown) are designed to stop when operating to blow out cold air.

Therefore, the low-temperature, low-pressure two-phase flow refrigerant whose pressure has been reduced by the expansion valve 5 is not heat-exchanged in the indoor heat exchanger 7, so the pressure of the low-pressure gas decreases, and it enters the accumulator 9 as it is, and becomes liquid refrigerant. As a result, the refrigerant circulation amount is reduced and the compressor input is also reduced, resulting in a longer 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.

This invention was made in order to eliminate the above-mentioned drawbacks of the conventional technology.A check valve and an oil separator are installed in this order between the discharge side of the compressor and the four-way valve, and a solenoid valve is connected to the oil separator. By returning the refrigerating machine oil to the accumulator through a bypass path, it is possible to prevent compressor failure due to a lack of refrigerating machine oil, and also to prevent valve damage and sliding due to poor lubrication caused by returning the refrigerating machine oil and liquid refrigerant directly to the compressor. Prevents seizure of moving parts.

In addition, by returning a portion of the gas discharged during defrosting to the accumulator, the low pressure is increased, and by sending highly concentrated refrigerant with a small specific volume to the compressor, the defrosting capacity is greatly increased, and defrosting is completed in a short time. do.

Furthermore, even if the refrigerant and refrigerating machine oil that had accumulated in the discharge piping system return to the discharge side of the compressor 1 due to their own weight and pressure when the air conditioner is stopped, they will be accumulated in the oil separator and the check valve This prevents it from entering the inside of the compressor discharge side and prevents the compressor valve from being damaged when the compressor is started.

Furthermore, when the compressor is stopped, the solenoid valve in the bypass path is closed, and the refrigerating machine oil discharged from the compressor is stored separately in the accumulator 9 and the oil separator 10, so that a small capacity accumulator 9 can be used. The purpose is to provide an air conditioner that makes it possible.

An embodiment of the present invention will be described below 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, an oil separator 10 is arranged between the discharge side of the compressor 1 and the four-way valve 2, and the oil separator 1
A bypass path 11 is provided from 0 to the accumulator 9, and a check valve is provided between the discharge side of the compressor 1 and the oil separator 10 to prevent the refrigerant and refrigeration oil from returning to the discharge side of the compressor 1. 13 is provided, and the check valve 13 is configured to be closed when the pressures before and after are the same.

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 oil discharged from the compressor 1 passes through the check valve 13 and enters the oil separator 1.
0, the refrigerant and refrigeration oil are separated,
Refrigerating machine oil collects at the bottom of the oil separator 10.

On the other hand, the refrigerant separated from the refrigerating machine oil is transferred to an oil separator 10.
From the upper part of the liquid, it passes through a four-way valve 2 and reaches an outdoor heat exchanger 3, where it is heat exchanged and becomes a high-temperature, high-pressure liquid. Thereafter, the pressure is reduced through the distributor 4, the expansion valve 5, the connection pipe 6, the indoor heat exchanger 7, the connection pipe 8, the four-way valve 2, the accumulator 9, and the compressor 1 again. return.

During this operation, the solenoid valve 12 located in the middle of the bypass path 11 is closed, but when oil accumulates, the solenoid valve 12 is opened by a signal, and the refrigerating machine oil that has accumulated at the bottom of the oil separator 10 is bypassed. It is returned to the accumulator 9 via the path 11 and returned to the compressor 1 together with the low-temperature, low-pressure gas returned from the indoor heat exchanger 7, thereby significantly shortening the refrigerating machine oil circulation circuit. The same applies to heating.

Therefore, when the distance between the indoor unit and the outdoor unit is large, that is, when the connection piping 6,
8 is long, the refrigerating machine oil circulation circuit is a short bypass circuit, so the compressor 1 will not run out of refrigerating machine oil.

In addition, when the compressor 1 is of the capacity control type, the circulating amount of refrigerant discharged from the compressor is significantly reduced, and even when the amount is small, that is, the speed of refrigerant moving in the refrigerant piping is reduced, the refrigerant oil is The distance of the circulation circuit remains the same, and because it is short, there is no possibility of insufficient return of refrigerating machine oil.

Furthermore, when the compressor 1 is started, the solenoid valve 12 is activated.
By keeping the refrigerant open for a certain period of time (for example, 1 minute), the refrigerant lying in the refrigerant oil when the compressor is stopped forms when the compressor starts, and a larger amount of refrigerant oil is discharged than in normal continuous operation. 11, returns to the accumulator 9, and returns to the compressor 1 together with low pressure gas. Therefore, it is possible to make up for the shortage of refrigerating machine oil in a short time, and it is also possible to prevent damage to the valves of the compressor and seizure of the sliding parts.

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 transferred to the check valve 13 and oil separator 10.
After that, defrost is performed in the outdoor heat exchanger 3 by the 4-way valve 2, the pressure is reduced by the expansion valve 5 through the distributor 4, and the connection pipe 6, the indoor heat exchanger 7, the connection pipe 8, and the 4-way valve Accumulator 9 after 2
will be returned to. At the same time, a portion of the high-temperature, high-pressure refrigerant gas exiting the compressor 1 is returned to the accumulator 9 from the lower part of the oil separator 10 via a bypass circuit 11 and a solenoid valve 12 .

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, the pressure of the low-pressure refrigerant gas is increased, and the gas is returned to the compressor 1. . As a result, a state with a small specific volume and a large circulation amount is created, and the frost formed on the outdoor heat exchanger 3 can be defrosted in a short time.

In addition, when heating at low temperatures, there is a risk of frost forming quickly, so the solenoid valve 12 is opened, and a portion of the refrigerant gas is bypassed into the accumulator 9 in the high temperature and high pressure discharged from the compressor 1 through the bypass path 11. This makes it possible to increase the heating capacity at low temperatures.

Furthermore, when a variable capacity compressor is used during the defrosting and heating at low temperatures, the capacity of the compressor 1 is set to maximum operation when the solenoid valve 12 is opened.
The defrosting ability and heating ability are even more effective.

Furthermore, during cooling or heating, the refrigerating machine oil that is constantly being discharged from the compressor 1 can be separated by opening the solenoid valve 12 after a certain continuous operating time (for example, 30 minutes) after starting the compressor 1. The refrigerating machine oil can be replenished by returning from the oil separator 10 stored in the oil separator 10 to the accumulator 9 via the bypass path 11 and returning to the compressor 1 together with the low temperature, low pressure refrigerant gas returned from the evaporator.

Also, because it is configured like this, when the air conditioner is stopped,
Even if the refrigerant accumulated in the connecting pipe 8 returns to the discharge pipe of the compressor due to its own weight, it is accumulated in the oil separator 10. Furthermore, the check valve 13 located between the oil separator 10 and the compressor discharge side closes based on the balance between the front and rear pressures, thereby preventing refrigerant and refrigeration oil from entering the inside of the compressor discharge port side. This prevents valve damage when the compressor is started, and the solenoid valve 12 is closed when the compressor is stopped, so the refrigerating machine oil can be stored separately in the accumulator 9 and the oil separator, and the accumulator 9 is small. It also has the effect of making it possible to use larger capacity devices.

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

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 bypass path is connected from the oil separator to the accumulator 9 via the solenoid valve 12. 11 is provided, and part of the refrigerating machine oil and high temperature, high pressure refrigerant gas is transferred to the accumulator 9.
Since it is configured so that the installation distance between the indoor side and the outdoor side (connecting pipes 6 and 8) can be made extremely long, the refrigerant discharge amount due to a variable capacity compressor etc. can be significantly reduced. However, the refrigerating machine oil can easily return to the compressor. In addition, defrost and heating low temperature characteristics are greatly improved, and a device that improves the heating characteristics, comfort, and reliability of a heat pump can be made extremely easily and inexpensively with high precision.

In addition, the check valve 13 provided in the passage connecting the discharge side of the compressor 1 and the oil separator 10 is configured to close when the pressures before and after the check valve are balanced, so that when the air conditioner is stopped, Even if the refrigerant gas and refrigeration machine oil that had accumulated in the discharge side connection pipe 8 return to the discharge pipe of the compressor due to their own weight, they will remain in the oil separator 10, and even if they overflow from the oil separator, there will be no backlash. Since the valve 13 can prevent the air from entering the discharge side of the compressor 1, and the valve can be prevented from being damaged when the compressor 1 is started, reliability will not be impaired even if the connecting pipe 8 is made long. Devices that do not currently exist can be made extremely easily and inexpensively, and with high accuracy.

Furthermore, since the solenoid valve in the bypass path is closed when the compressor is stopped, the refrigerating machine oil can be stored separately in the accumulator and oil separator, making it possible to use a small-capacity accumulator to downsize the entire system. There are various excellent effects such as:

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a conventional air conditioner, and FIG. 2 is a block diagram showing an air conditioner according to 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
1 is a bypass path, 12 is a solenoid valve, and 13 is a check valve. Solid arrows represent the flow of refrigerant during cooling and defrosting operations, dashed arrows represent the flow of refrigerant during heating operation, and dashed lines represent 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. In an air conditioner in which a compressor, a four-way valve, an outdoor heat exchanger, a throttling device, an indoor heat exchanger, and an accumulator are connected in a ring to form a circulation cycle, the discharge side of the compressor 1 and the An oil separator 10 is provided between the two-way valve 2, and a solenoid valve 12 that is closed at least when the compressor is stopped is provided in a bypass path 11 leading from the oil separator to the accumulator 9.
is provided, and the discharge side of the compressor 1 and the oil separator 1 are connected to each other.
1. An air conditioner characterized in that a check valve 13 is provided between the compressor and the compressor to prevent refrigerant and refrigerating machine oil from returning to the discharge side of the compressor.