JPH0921569A - Refrigerator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerator capable of eliminating a two-layer separation when refrigerant and lubricating oil are two-layer separated in a compressor. SOLUTION: The refrigerator comprises a bypass tube for connecting the discharge tube 5 extended from a compressor 1 to the bottom 3A of the oil reservoir 3 of the compressor 1, a solenoid valve 6 provided at the bypass tube, and valve switching means for opening the valve 6 when two-layer separation occurs and closing the valve 6 when no two-layer separation occurs. When the two-layer separation occurs, the valve 6 is opened, the refrigerant stored in the bottom 3A of the reservoir 3 of the compressor 1 is fed from the bypass tube to the tube 5 to reduce the refrigerant amount in the compressor, thereby eliminating the two-layer separation.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerator that uses oil having substantially no compatibility with a refrigerant and a specific gravity smaller than that of the refrigerant as lubricating oil for a compressor. The present invention relates to a refrigerator that can eliminate two-layer separation from oil.

[0002]

2. Description of the Related Art Conventionally, when an oil that is incompatible with a refrigerant is used in a refrigerator, as shown by a black dot in FIG. When dissolved, a two-layer separation occurs where the oil and refrigerant split into two layers. And
At this time, if (specific gravity of refrigerant)> (specific gravity of oil), the lower layer becomes a refrigerant rich layer having an extremely low oil concentration.

As an operation mode in which the two-layer separation occurs,
There are modes in which liquid back occurs transiently, such as startup (sleep activation), start / stop, and defrost. Then, when the two-layer separation occurs in the oil sump of the compressor of the refrigerator, the two-layer separation surface D crosses the oil supply port S depending on conditions, as shown in FIG. 8 (B). Then, the oil in the lower liquid refrigerant rich layer R is sucked in through the oil supply port S and is supplied to the sliding portion of the compressor C without oil being sucked in through the oil supply port S. Then, there is a problem that the lubrication failure of the compressor C occurs, causing friction and seizure of the sliding portion.

[0004]

SUMMARY OF THE INVENTION Therefore, when the refrigerant and the lubricating oil are separated into two layers in the compressor, the object of the present invention is to eliminate this two-layer separation and prevent sliding portion friction and seizure. It is to provide a refrigerator that can do the above.

[0005]

In order to achieve the above object, the invention of claim 1 lubricates the compressor 1 with oil having a specific gravity smaller than that of the refrigerant and substantially incompatible with the refrigerant. In a refrigerator used as oil, two-layer separation detecting means 8 for detecting that the refrigerant and the lubricating oil are separated into two layers in the compressor 1, and a refrigerant pipe of a refrigerant circuit connected to the compressor 1. 5, 11, 16 and the bypass pipe 2 that connects the bottom portion 3A of the oil sump portion 3 of the compressor 1, the bypass valve 6 provided in the bypass pipe 2, and the two-layer separation detecting means 8 The bypass valve 6 when the layer separation is detected
On the other hand, a bypass valve opening / closing means 10 for closing the bypass valve 6 when the two-layer separation detecting means 8 does not detect the two-layer separation is provided.

According to the first aspect of the present invention, the bypass valve opening / closing means 10 opens the bypass valve 6 when the two-layer separation detecting means 8 detects the two-layer separation. Then, the refrigerant accumulated in the bottom portion 3A of the oil sump portion 3 of the compressor 1 flows into the refrigerant pipe 5 of the refrigerant circuit through the bypass pipe 2. Therefore, the two-layer separation surface at the compressor bottom 3 is reduced. Moreover, since the amount of the refrigerant in the compressor 1 is reduced, the two-layer separation is eliminated. Therefore, insufficient lubrication and seizure of the compressor 1 can be prevented. In the high-pressure dome type compressor, the refrigerant is automatically supplied to the refrigerant pipe from the bottom of the oil sump due to the pressure difference. A pump is used in a low pressure dome type compressor.

The invention according to claim 2 is a refrigerator in which oil having a specific gravity smaller than that of a refrigerant and substantially incompatible with the refrigerant is used as lubricating oil for the compressor 1.
Based on the output of the two-layer separation detecting means 21 for detecting that the refrigerant and the lubricating oil are separated into two layers in the compressor 1, the two-layer separation detecting means 21 is From the time when the two-layer separation is detected, the above-mentioned two-layer separation detecting means 2
1 is provided with a compressor continuous operation means 23 for continuously operating the compressor 1 after the two-layer separation is no longer detected.

According to the second aspect of the present invention, the compressor continuous operation means 23 detects the two-layer separation when the two-layer separation detecting means 21 detects the two-layer separation. The compressor 1 is continuously operated until after that. By continuously operating the compressor 1 without starting and stopping, the refrigerant can be discharged from the compressor 1 and the amount of the refrigerant in the compressor 1 can be reduced. Therefore, the separation of the two layers in the compressor 1 can be eliminated, and the refrigerant can be prevented from accumulating at the bottom of the compressor 1, so that insufficient lubrication and seizure of the compressor 1 can be prevented.

Further, the invention of claim 3 is a refrigerator in which oil having a specific gravity smaller than that of the refrigerant and substantially incompatible with the refrigerant is used as lubricating oil for the compressor 1.
An outside air temperature sensor 31 that detects an outside air temperature and a signal indicating the outside air temperature from the outside air temperature sensor 31 are received, and the lower the outside air temperature, the longer the compressor 1 is continuously operated when the compressor 1 starts up. And a machine continuous operation means 33.

According to the third aspect of the invention, the compressor continuous operation means 33 receives a signal indicating the outside air temperature from the outside air temperature sensor 31, and the lower the outside air temperature is, the more the compressor 1 is started up. 1 is continuously operated for a long time. By this continuous operation, the amount of refrigerant in the compressor 1 can be reduced and the two-layer separation can be eliminated. Further, the lower the outside air temperature, the lower the refrigerant temperature and the easier the two-layer separation. Therefore, the longer the continuous operation time is, the longer the outside air temperature is, and thus the two-layer separation can be sufficiently eliminated.

Further, the invention of claim 4 is a refrigerator in which oil having a specific gravity smaller than that of the refrigerant and substantially incompatible with the refrigerant is used as lubricating oil for the compressor 1.
In response to the outside air temperature sensor 42 that detects the outside air temperature and the signal that indicates the outside air temperature from the outside air temperature sensor 42, the opening degree of the expansion valve 15 during the start / stop operation is not stopped when the outside air temperature is lower. An expansion valve control means 45 for reducing the opening degree of the expansion valve 15 during operation is provided.

According to the fourth aspect of the invention, the expansion valve control means 45 receives the signal indicating the outside air temperature from the outside air temperature sensor 42, and the lower the outside air temperature, the more the expansion valve during start-stop operation. The opening degree of 15 is made smaller than the opening degree of the expansion valve 15 at the time of non-stop operation. By throttling the expansion valve 15, the degree of superheat increases, the temperature of the refrigerant increases, and the lubricating oil easily dissolves in the refrigerant. Further, by throttling the expansion valve 15, the amount of liquid refrigerant returning to the compressor 1 is also reduced. Therefore, the two-layer separation in the compressor 1 can be eliminated, and insufficient lubrication of the compressor 1 can be prevented.

The invention according to claim 5 is a refrigerator in which oil having a specific gravity smaller than that of the refrigerant and substantially incompatible with the refrigerant is used as lubricating oil for the compressor 1.
The two-layer separation detecting means 51 for detecting that the refrigerant and the lubricating oil are separated into two layers in the compressor 1, and the two-layer separation detecting means 51 based on the output of the two-layer separation detecting means 51. When the two-layer separation is detected, the drive frequency of the power source for driving the compressor 1 is made higher than the drive frequency when the two-layer separation is not detected, and the two-layer separation detecting means 51 causes the two-layer separation to be performed. It is characterized in that it is provided with a compressor control means 55 for continuously operating the compressor 1 at the increased drive frequency until no longer detected.

According to the fifth aspect of the present invention, the compressor control means 55 is more effective when the two-layer separation detecting means 51 detects the two-layer separation than when it does not detect the two-layer separation.
The drive frequency of the power supply for driving the compressor 1 is increased, and the compressor 1 is continuously operated at the increased drive frequency.
The continuous operation of the compressor 1 at this increased drive frequency allows the refrigerant in the compressor 1 to be quickly discharged.
Therefore, the two-layer separation in the compressor 1 can be eliminated quickly. Therefore, it is possible to prevent only the refrigerant from being supplied to the compressor 1 and prevent insufficient lubrication and seizure of the compressor 1.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments shown in the drawings.

[First Example] FIG. 1A shows a basic configuration of a control system of a first example of the refrigerator of the present invention. Also, FIG. 2 (A)
The structure around the compressor 1 of the first example is shown in FIG. This first
The refrigerator of the example uses, as the lubricating oil of the compressor 1, an oil having a specific gravity smaller than that of the refrigerant and having substantially no compatibility with the refrigerant as the lubricating oil of the compressor 1. The compressor 1 has a motor M, a drive unit A driven by the motor M, and an oil supply port 1A for supplying oil to the drive unit A.

As shown in FIG. 2A, this first example includes a bypass pipe 2A. This bypass piping 2A
Connects the bottom portion 3A of the oil sump portion 3 of the compressor 1 and the discharge pipe 5 extending from the compressor 1. Further, the bypass pipe 2A is provided with a solenoid valve 6 as a bypass valve. Further, a flow rate adjusting capillary 7 is provided on the downstream side of the electromagnetic valve 6. In addition, 11 is an intake pipe and 12 is an accumulator. Also, L1
Is an oil rich layer, and L2 is a liquid refrigerant rich layer.

Further, as shown in FIG. 1 (A), this first example comprises a two-layer separation detecting section 8 and a bypass circuit solenoid valve control circuit 10 as a control system. The two-layer separation detector 8
Is for detecting a two-layer separation in the compressor 1. Then, the bypass circuit solenoid valve control circuit 10 opens the solenoid valve 6 when the two-layer separation detecting unit 8 detects the two-layer separation, while the two-layer separation detecting unit 8 does not detect the two-layer separation. Close valve 6.

In the refrigerator having the above-described structure, when the oil concentration at the oil supply port 1A of the compressor 1 is lowered at the time of start-up and two-layer separation occurs, the two-layer separation occurs, as indicated by the one-dot chain line in the lower left of FIG. The detection unit 8 detects the two-layer separation. Then, the solenoid valve control circuit 10 opens the solenoid valve 6 to communicate the bypass pipe 2. Then, the refrigerant flows from the bottom portion 3A of the oil sump portion 3 of the compressor 1 to the discharge pipe 5 through the bypass pipe 2. Then, the amount of the refrigerant in the oil sump portion 3 decreases, and the concentration of the oil in the oil supply port 1A increases rapidly as shown by the alternate long and short dash line in the lower left of FIG. Separation is eliminated. As can be seen by comparing the oil concentration transition in this example shown by the above-mentioned one-dot chain line with the oil concentration transition in the conventional example shown by the broken line on the lower left of FIG. 3, according to this example,
The time from the occurrence of separation of two layers to the elimination thereof can be reduced to one fifth or less as compared with the conventional example. Therefore, according to this example, it is possible to quickly eliminate the two-layer separation at the time of startup. Therefore, it is possible to prevent the refrigerant from being sucked from the oil supply port 1A, and to prevent the sliding portion of the compressor 1 from being worn or seized.

The upper part of FIG. 3 shows the transition of the oil temperature in the compressor at the time of starting. The alternate long and short dash line shows the transition of the oil temperature in this example, and the broken line shows the transition of the oil temperature in the conventional example. The solid line in the upper part of FIG. 3 shows the transition of the saturation temperature of the refrigerant, which is determined by the pressure inside the high-pressure dome of the compressor 1. As can be seen by referring to the upper part of FIG. 3, the oil temperature of this example shown by the alternate long and short dash line exceeds the refrigerant saturation temperature within 2 minutes after startup, whereas the oil temperature of the conventional example shown by the broken line is The refrigerant saturation temperature could not be exceeded within 10 minutes after the start.

According to this example, since the liquid refrigerant accumulated in the oil sump portion 3 of the compressor 1 is physically discharged into the refrigerant circulation system, not only the two-layer separation can be avoided but also the refrigerant at the time of start-up. The shortage of the refrigerant in the circulation system can be eliminated, and the warm-up of the compressor 1 can be promoted. Therefore, there is an advantage that the quick heating property can be improved.

In this example, since the high-pressure dome type compressor was used as the compressor 1, the refrigerant could be automatically supplied from the bottom of the oil sump 3 to the pipe 5 by the pressure difference. When typed, a pump is used. Further, in this first example, as shown in FIG. 2 (A), the bypass pipe 2 was connected to the discharge pipe 5.
As shown in (B), connect the bypass pipe 2-B to the heat exchanger 13
And the expansion valve 15 may be connected to the liquid line 16. Further, as shown in FIG. 2 (C), the bypass pipe 2-C may be connected to the suction pipe 11 connected to the accumulator 12.

[Second Example] Next, FIG. 1B shows the configuration of a control system of a second example of the refrigerator of the present invention. The configuration of the compressor and the piping around the compressor of the second example differs from the first example only in that the bypass piping 2 shown in FIG. 2 (A) is not provided. Therefore, in this second example, the configuration of the control system will be mainly described.

As shown in FIG. 1B, the second example includes a two-layer separation detecting section 21, a normal control circuit 22, and a two-layer separation countermeasure control circuit 23 as a control system configuration. The two-layer separation countermeasure control circuit 23 constitutes a compressor continuous operation means.

The two-layer separation detecting section 21 detects that the refrigerant and the lubricating oil are separated into two layers in the compressor 1.
Further, the two-layer separation countermeasure control circuit 23 causes the compressor 1 to continuously operate when the two-layer separation detecting unit 21 detects the two-layer separation based on the output from the two-layer separation detecting unit 21, This continuous operation is continued from the time t _{1 when the} two-layer separation detecting unit 21 no longer detects the two-layer separation until the time when Δt time has elapsed.

In the refrigerator having the above-described structure, as shown in the lower left of FIG. 4, when the oil concentration at the oil supply port 1A decreases and two-layer separation occurs, the two-layer separation detector 21 causes the two-layer separation detector 21 to Detect layer separation. Then, the two-layer separation countermeasure control circuit 23
Receives a signal indicating that the two-layer separation has occurred from the two-layer separation detection unit 21 and continuously operates the compressor 1.
The duration of this continuous operation is the time t when the two-layer separation is resolved.
_{It is} continued until the time (10 minutes from the start time) when Δt time has passed from ₁ further.

As described above, according to this example, when the two-layer separation occurs at the time of startup, the compressor 1 is forcibly operated continuously without starting and stopping the operation of the compressor 1. As a result, the refrigerant can be quickly discharged from the compressor 1. Therefore, the refrigerant concentration in the compressor 1 can be promptly reduced to eliminate the two-layer separation, and the oil concentration at the oil supply port 1A can be increased. Therefore, insufficient lubrication of the compressor 1 can be prevented in advance.

In this continuous operation, the drive frequency of the compressor 1 is set to 60 Hz. This drive frequency of 60 Hz, as shown by the broken line in the upper part of FIG.
The drive frequency is 20 Hz higher than the standard drive frequency of 40 Hz. In this way, by driving the compressor 1 at a frequency higher than the standard, the refrigerant can be discharged from the compressor 1 more quickly. Therefore, the two-layer separation can be eliminated more quickly.

Further, according to this example, it is possible to simply change the control system without complicating the conventional refrigerant piping system.
Since the separation of the two layers can be avoided, the reliability of the compressor can be improved without increasing the cost.

The dashed line in the upper part of FIG. 4 shows the oil temperature in the compressor 1, and the solid line shows the saturation temperature of the refrigerant determined by the dome internal pressure. At time t1,
The oil temperature has reached the saturation temperature.

[Third Example] Next, FIG. 1C shows the configuration of a control system of a third example of the refrigerator of the present invention. The configuration of the compressor and the pipes around the compressor of the third example is different from that of the first example only in that the bypass pipe 2 shown in FIG. 2 (A) is not provided. Therefore, this third example will focus on the configuration of the control system.

As shown in FIG. 1C, in this third example, the control system has an outside air temperature sensor 31, an operation mode detection unit 32, a continuous operation time calculation unit 33, and a two-layer separation countermeasure control circuit 34. And a normal control circuit 35. The outside air temperature sensor 31 detects the outside air temperature and outputs a signal indicating the outside air temperature to the continuous operation time calculation unit 33. Further, the operation mode detection unit 32 detects whether the refrigerator is performing the cooling operation or the heating operation, and outputs an operation detection signal indicating this detection to the continuous operation time calculation unit 33. Then, the continuous operation time calculation unit 33 receives the signal from the outside air temperature sensor 31 and the operation detection signal, and calculates the time T during which the compressor 1 is continuously operated.
In this calculation, the lower the outside temperature is, the longer the continuous operation time T is set, and the longer the continuous operation time T is during the heating operation than during the cooling operation. Then, the calculation unit 33 outputs a signal representing the calculated continuous operation time T to the two-layer separation countermeasure control circuit 34. Then, the countermeasure control circuit 34 continuously operates the compressor 1 for the continuous operation time T so that the two-layer separation generated in the compressor 1 can be eliminated. For example, the continuous operation time T may be set as shown in FIG. 6 according to the outside air temperature, and the set operation time may be corrected depending on whether it is during cooling operation or heating operation. Good.

Then, the countermeasure control circuit 34 outputs a signal indicating that the continuous operation is completed to the normal control circuit 35 when the continuous operation is completed. Then, the normal control circuit 35 executes normal compressor control including start / stop of the compressor 1.

According to this example, the continuous operation time calculating unit 33
Sets the compressor continuous operation time T that can eliminate the two-layer separation in accordance with the outside air temperature and the cooling / heating operation mode, so that it is possible to eliminate insufficient lubrication of the compressor 1 and prevent wear and seizure. it can.

Further, according to this example, by simply changing the control system without complicating the conventional refrigerant piping system,
Since the separation of the two layers can be avoided, the reliability of the compressor can be improved without increasing the cost.

[Fourth Example] Next, FIG. 1D shows the configuration of the control system of the fourth example of the present invention. The fourth example includes a start / stop mode determination unit 41, an outside air temperature sensor 42, a normal expansion valve control circuit 43, and a start / stop expansion valve control circuit 45. The refrigerant circulation system of the fourth example is the same as the compressor 1 of the second example.
And a refrigerant pipe around the compressor 1. further,
The refrigerant circulation system of this example has a compressor 1 as shown in FIG.
The heat exchanger 13 connected to the heat exchanger 13 and the electric expansion valve 15 connected to the heat exchanger 13 are provided.

In the refrigerator having the above structure, first, the start / stop mode determination unit 41 determines whether the refrigerator is in the start / stop mode. When the start / stop mode determination unit 41 determines that the refrigerator is not in the start / stop mode but in the normal operation mode, the start / stop mode determination unit 41 notifies the normal expansion valve control circuit 43 of the normal operation mode signal. Is output. Then, the normal expansion valve control circuit 43 outputs a pulse signal to the electric expansion valve 15 to set the opening degree of the electric expansion valve 15 to the expansion valve opening degree determined in the normal operation.

On the other hand, when the start / stop mode determination unit 41 determines that the refrigerator is in the start / stop mode, the start / stop mode determination unit 41 sends a start / stop mode signal to the start / stop expansion valve control circuit 45. Output. Then, the start-stop expansion valve control circuit 45
Outputs a pulse signal to the electric expansion valve 15 to make the opening of the electric expansion valve 15 smaller than the opening of the expansion valve 15 during normal operation. Specifically, as shown in FIG. 5, the electric expansion valve opening degree during normal operation is 120
It is the opening degree of the electric expansion valve when outputting a pulse. When the two-layer separation occurs at the electric expansion valve opening degree with 120 pulses, the start-stop expansion valve control circuit 45
Squeezes the electric expansion valve 15 so that the opening of the electric expansion valve 15 becomes the electric expansion valve opening at 100 pulses. When the electric expansion valve 15 is throttled, the degree of superheat increases and the temperature of the refrigerant increases, so that the solubility of the refrigerant can be improved and
The amount of liquid refrigerant returned to the compressor 1 also decreases. Therefore, the two-layer separation can be eliminated. Therefore, the oil concentration at the oil supply port 1A can be increased, and insufficient lubrication or seizure of the compressor 1 can be prevented.

Further, in this example, the on-off-time expansion valve control circuit 45 corrects the amount by which the opening degree of the expansion valve 15 is reduced in response to a signal representing the outside air temperature from the outside air temperature sensor 42. . That is, the start-stop expansion valve control circuit 45 shifts the amount by which the opening degree of the expansion valve 15 is made smaller as the outside air temperature becomes higher. The reason is that the higher the outside air temperature, the higher the temperature of the refrigerant even if the opening degree of the electric expansion valve is the same. It is possible to prevent the electric expansion valve 15 from being excessively throttled and opened too much by adjusting the electric expansion valve opening throttle amount according to the level of the outside air temperature.

Further, according to this example, the control system is simply changed without complicating the refrigerant piping system of the conventional example.
Since the separation of the two layers can be avoided, the reliability of the compressor can be improved without increasing the cost.

[Fifth Example] Next, FIG. 1 (E) shows the configuration of a control system of a fifth example of the refrigerator of the present invention. In this fifth example, the two-layer separation detector 51, the outside air temperature sensor 52, and the normal control circuit 5 are included.
3 and a two-layer separation countermeasure control circuit 55. The two-layer separation countermeasure control circuit 55 has a compressor frequency-on time calculation unit 56 and a countermeasure operation unit 57. Further, the fifth example has the same compressor 1 and the refrigerant circuit around the compressor as in the second example.

The operation of the refrigerator having the above structure will be described with reference to FIG. First, at start-up, the oil concentration at the oil supply port 1A of the compressor 1 is about 80 wt%, and since it is in the refrigerant dissolution region, two-layer separation has not occurred. Therefore, the two-layer separation detector 51 does not detect the two-layer separation. Therefore, the two-layer separation detector 51 outputs a signal indicating that the two-layer separation has not occurred to the normal control circuit 53. And
The normal control circuit 53 normally operates the compressor 1. That is,
The control circuit 53 operates the compressor 1 at a normal frequency, and executes a normal start / stop control for turning on / off the compressor 1 as shown in the lower left of FIG. 7.

Next, when the oil concentration at the oil supply port 1A decreases to about 30%, the two-layer separation detecting section 51 performs two-layer separation in which the refrigerant and the oil are separated into two layers in the compressor 1. A signal indicating that the two-layer separation has occurred is output to the two-layer separation countermeasure control circuit 55. In addition, the countermeasure control circuit 55 includes
A temperature signal representing the outside air temperature is input from the outside air temperature sensor 52. Then, the calculation unit 56 of the countermeasure control circuit 55
As shown in FIG. 6, the countermeasure operating time of the compressor 1, that is, the continuous operating time is determined according to the outside air temperature represented by the temperature signal. Further, the calculation unit 56 increases the drive frequency of the compressor 1 by a predetermined ratio as compared with the drive frequency during normal operation, based on the output signal from the two-layer separation detection unit 51. For example, the drive frequency during normal operation is 40 Hz
If so, the drive frequency during the above countermeasure operation is set to 60 Hz.

In this way, by increasing the drive frequency of the compressor 1 and then continuously operating the compressor 1 for a continuous operation time determined by the outside air temperature, the amount of refrigerant discharged from the compressor 1 is increased. . As a result, as shown in the middle of FIG. 7, the oil concentration at the oil supply port 1A can be rapidly increased, the two-layer separation surface is raised, and finally the oil concentration reaches the melting region of the refrigerant. Therefore, the two-layer separation can be eliminated. Therefore, the filler port 1A of the compressor 1
It is possible to prevent the refrigerant from being sucked from the compressor 1 and prevent the compressor 1 from being worn or seized.

When the two-layer separation is eliminated, the two-layer separation detection section 51 no longer detects the two-layer separation, so that the normal control circuit 53 outputs a signal indicating that the two-layer separation has not occurred. Output. Then, the normal control circuit 53 operates the compressor 1 at the normal drive frequency, cancels the forced continuous operation, and returns to the normal operation including ON and OFF.

According to this example, since the two-layer separation can be avoided only by changing the control system without complicating the refrigerant piping system of the conventional example, the reliability of the compressor can be increased without increasing the cost. It is possible to improve the sex.

[0047]

As is apparent from the above, the refrigerator according to the invention of claim 1 has a two-layer separation detecting means for detecting that the refrigerant and the lubricating oil are separated into two layers in the compressor; Bypass pipe connecting the refrigerant pipe of the refrigerant circuit connected to the machine and the bottom of the oil sump of the compressor, the bypass valve provided in the bypass pipe, the two-layer separation detection means for the two-layer separation When the detection is made, the bypass valve is opened, and when the two-layer separation detecting means does not detect the two-layer separation, the bypass valve opening / closing means is provided to close the bypass valve.

Therefore, according to the first aspect of the invention, the bypass valve opening / closing means opens the bypass valve when the two-layer separation detecting means detects the two-layer separation. Then, the refrigerant accumulated at the bottom of the oil sump of the compressor flows through the bypass pipe to the refrigerant pipe of the refrigerant circuit. Therefore, the two-layer separation surface at the bottom of the compressor is reduced. Further, since the amount of refrigerant in the compressor is reduced, the two-layer separation is eliminated. Therefore, insufficient lubrication and seizure of the compressor can be prevented.

In the invention of claim 2, the two-layer separation detecting means for detecting that the refrigerant and the lubricating oil are separated into two layers in the compressor, and the two-layer separation detecting means for separating the two layers. When it is detected, at least the two-layer separation detecting means is provided with a compressor continuous operation means for continuously operating the compressor until after the two-layer separation detection means stops detecting the two-layer separation.

Therefore, according to the invention of claim 2, in the compressor continuous operation means, the two-layer separation detecting means detects the two-layer separation when the two-layer separation detecting means detects the two-layer separation. The compressor is continuously operated until it runs out. By continuously operating the compressor without starting and stopping, it is possible to discharge the refrigerant from the compressor and reduce the amount of the refrigerant in the compressor. Therefore, it is possible to eliminate the two-layer separation in the compressor, it is possible to prevent the refrigerant from accumulating at the bottom of the compressor,
Insufficient lubrication and seizure of the compressor can be prevented.

According to a third aspect of the present invention, the outside air temperature sensor for detecting the outside air temperature and a signal indicating the outside air temperature from the outside air temperature sensor are received, and the lower the outside air temperature is, the more the above-mentioned condition occurs when the compressor is started. And a compressor continuous operation means for continuously operating the compressor for a long time. Therefore, according to the third aspect of the invention, the compressor continuous operation means receives the signal representing the outside air temperature from the outside air temperature sensor, and the lower the outside air temperature, the longer the continuous operation of the compressor at the time of starting the compressor. Let
By this continuous operation, the amount of refrigerant in the compressor can be reduced and the two-layer separation can be eliminated. Also, the lower the outside air temperature, the lower the refrigerant temperature and the easier it is to separate into two layers.
The longer the continuous operation time as the outside air temperature is lower, the more reliable separation of the two layers can be achieved.

Further, according to the invention of claim 4, the outside air temperature sensor for detecting the outside air temperature and the signal representing the outside air temperature from the outside air temperature sensor are received, and the lower the outside air temperature, the more the start / stop operation is performed. And an expansion valve control means for making the opening of the expansion valve smaller than the opening of the expansion valve during non-stop operation.

Therefore, according to the fourth aspect of the present invention, the expansion valve control means receives the signal indicating the outside air temperature from the outside air temperature sensor, and the lower the outside air temperature, the more the expansion valve during start-stop operation. The opening of the expansion valve is made smaller than the opening of the expansion valve during non-stop operation. By throttling the expansion valve, the degree of superheat increases, the temperature of the refrigerant increases, and the lubricating oil easily dissolves in the refrigerant. Also, by throttling the expansion valve, the amount of liquid refrigerant returning to the compressor is also reduced. Therefore, it is possible to eliminate the two-layer separation in the compressor and prevent insufficient lubrication of the compressor.

According to a fifth aspect of the present invention, the two-layer separation detecting means for detecting that the refrigerant and the lubricating oil are separated into two layers in the compressor, and the two-layer separation detecting means for separating the two layers. When detecting the, the drive frequency of the power source for driving the compressor is increased, and the compressor is continuously operated at the increased drive frequency until the two-layer separation detecting means no longer detects the two-layer separation. And a compressor control means.

Therefore, according to the invention of claim 5, the compressor control means is based on the output from the two-layer separation detecting means when the two-layer separation detecting means detects the two-layer separation. The drive frequency of the power source for driving the compressor is made higher than the drive frequency when the two-layer separation is not detected, and the compressor is continuously operated at the increased drive frequency. By continuously operating the compressor at this increased drive frequency, the refrigerant in the compressor can be quickly discharged.
Therefore, the two-layer separation in the compressor can be eliminated quickly. Therefore, it is possible to prevent only the refrigerant from being supplied to the compressor and prevent insufficient lubrication or seizure of the compressor.

[Brief description of drawings]

1 (A) is a block diagram showing a configuration of a first example of a refrigerator of the present invention, FIG. 1 (B) is a block diagram showing a configuration of a second example, and FIG. ) Is a block diagram showing the configuration of the third example, FIG. 1 (D) is a block diagram showing the configuration of the fourth example, and FIG. 1 (E) is a block diagram showing the configuration of the fifth example.

FIG. 2 (A) is a refrigerant piping diagram showing a main part structure of a first example, FIG. 2 (B) is a piping diagram of a modified example of the first example, and FIG. 2 (C) is another. It is a piping diagram of one modification.

FIG. 3 is a diagram showing a manner in which the two-layer separation is resolved over time at the time of startup in the first example and the conventional example.

FIG. 4 is a diagram showing a manner in which the two-layer separation at the time of startup is resolved with the passage of time by the second example.

FIG. 5 is a diagram showing that in the fourth example, as the opening degree of the motor-operated valve is reduced, the oil concentration at the oil supply port in the compressor can be increased.

FIG. 6 is a diagram showing how the continuous operation time of the compressor is lengthened as the outside air temperature decreases in the fifth example.

FIG. 7 is an operation time chart of the fifth example.

FIG. 8 (A) is a two-layer separation diagram showing a two-layer separation region with respect to temperature and refrigerant fraction, and FIG. 8 (B) is a schematic diagram showing a two-layer separation state in the compressor. .

[Explanation of symbols]

1 ... Compressor, M ... Motor, A ... Drive part, 1A ... Refueling port,
2 ... Bypass piping, 3 ... Oil sump, 3A ... Bottom, 5 ...
Discharge pipe, 6 ... Solenoid valve, 7 ... Capillary, 8, 21, 5
DESCRIPTION OF SYMBOLS 1 ... Two-layer separation detection part, 10 ... Bypass circuit Solenoid valve control circuit, 11 ... Suction piping, 12 ... Accumulator, 13 ... Heat exchanger, 15 ... Electric expansion valve, 16 ... Liquid line, 22 ... Countermeasure control circuit, 23 55, two-layer separation countermeasure control circuit, 31,
42, 52 ... Outside air temperature sensor, 32 ... Operating mode detector,
33 ... Continuous operation time calculation unit, 34 ... Two-layer separation countermeasure control circuit, 35, 53 ... Normal control circuit, 41 ... Start / stop mode determination unit, 43 ... Normal expansion valve control circuit, 45 ... Start / stop expansion valve control circuit , 56 ... Compressor frequency-ON time calculation unit, 57 ...
Countermeasure driving department.

Claims (5)

[Claims] 1. A refrigerating machine in which an oil having a specific gravity smaller than that of a refrigerant and substantially incompatible with the refrigerant is used as a lubricating oil of a compressor (1), the refrigerant and the lubricating oil are compressed. Two-layer separation detecting means (8) for detecting separation into two layers in the machine (1), and refrigerant pipes (5, 11, 1) of a refrigerant circuit connected to the compressor (1).
6) and a bypass pipe (2) connecting the bottom (3A) of the oil sump (3) of the compressor (1), a bypass valve (6) provided in the bypass pipe (2), The two-layer separation detecting means (8) opens the bypass valve (6) when the two-layer separation is detected, while the two-layer separation detecting means (8) does not detect the two-layer separation. A refrigerator comprising a bypass valve opening / closing means (10) for closing (6). 2. A refrigerating machine in which oil having a specific gravity smaller than that of a refrigerant and substantially incompatible with the refrigerant is used as a lubricating oil of a compressor (1), the refrigerant and the lubricating oil are compressed. A two-layer separation detecting means (21) for detecting separation into two layers in the machine (1), and the two-layer separation detecting means (21) based on the output of the two-layer separation detecting means (21). The continuous operation means (23) for continuously operating the compressor (1) from when the two-layer separation is detected by the two-layer separation detection means (21) until the two-layer separation detection means (21) stops detecting the two-layer separation. A refrigerator characterized by being provided. 3. An outside air temperature for detecting an outside air temperature in a refrigerator using oil having a specific gravity smaller than that of the refrigerant and substantially incompatible with the refrigerant as a lubricating oil of the compressor (1). By receiving a signal indicating the outside air temperature from the sensor (31) and the outside air temperature sensor (31), the lower the outside air temperature, the longer the continuous operation of the compressor (1) when the compressor (1) is started. A refrigerator comprising a compressor continuous operation means (33). 4. An outside air temperature for detecting an outside air temperature in a refrigerator that uses oil having a specific gravity smaller than that of a refrigerant and substantially incompatible with the refrigerant as a lubricating oil of a compressor (1). In response to the sensor (42) and a signal indicating the outside air temperature from the outside air temperature sensor (42), the lower the outside air temperature is, the more the opening degree of the expansion valve (15) during the start / stop operation is changed to the non-start / stop operation. A refrigerator comprising: an expansion valve control means (45) for reducing the opening degree of the expansion valve (15) in time. 5. A refrigerating machine using oil having a specific gravity smaller than that of a refrigerant and having substantially no compatibility with the refrigerant as a lubricating oil of a compressor (1), wherein the refrigerant and the lubricating oil are compressed. Two-layer separation detecting means (51) for detecting separation into two layers in the machine (1), and the two-layer separation detecting means (51) based on the output of the two-layer separation detecting means (51). When the two-layer separation is detected, the drive frequency of the power source for driving the compressor (1) is made higher than the drive frequency when the two-layer separation is not detected, and the two-layer separation detecting means (51). And a compressor control means (55) for continuously operating the compressor (1) at the increased drive frequency until the two-layer separation is no longer detected.