JP3606883B2 - Rotary compressor cooling system - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a cooling device for a hermetic rotary compressor.
[0002]
[Prior art]
As disclosed in Japanese Patent Publication No. 58-10588, conventionally, as a cooling mechanism of a compression mechanism, as shown in FIG. 4, the discharged refrigerant gas is led to the outside of the sealed container a, and the discharged refrigerant gas is discharged by the preliminary heat exchanger b. There is an intermediate cooling method in which the cooling is performed and then returned to the sealed container a. However, in this intermediate cooling method, since a large amount of discharged refrigerant passes through the preliminary heat exchanger b, the refrigerant returning to the sealed container a is almost always dry steam, and the cooling of the preliminary heat exchanger b When is significantly large, a part of the vapor is liquefied. In the case of dry steam, since the lubricating oil around the compression mechanism c is hardly cooled, the cooling effect of the compression mechanism c cannot be obtained. When the return gas contains liquid, the liquid refrigerant enters the lubricating oil and is heated and evaporated to cool the lubricating oil, so that the cooling effect of the compression mechanism c can be obtained, but the liquid refrigerant evaporates. As a result, the lubricating oil is foamed, and the refrigerant gas of the liquid refrigerant is sucked from the lubricating oil suction port d, thereby hindering lubrication.
[0003]
As another cooling method, as shown in FIG. 5, in a refrigeration cycle in which a compressor e, a condenser f, a capillary tube g, and an evaporator h are connected in a ring shape, a high-pressure liquefied refrigerant is drawn from the condenser f, There is an injection method in which is injected directly into the cylinder i. In this injection method, the effect of directly cooling the compression mechanism j can be obtained, but since there is a useless compression step of compressing the injected refrigerant again, the efficiency of the compressor is conversely reduced.
[0004]
In addition, as shown in FIG. 6, the discharged refrigerant gas stagnated in the radiator 9 that forms a refrigerant passage in parallel with the refrigerant passage in the hermetic container is cooled by the radiator to produce liquid refrigerant, and the compression mechanism Since the cooling method is based on natural circulation, a large cooling effect cannot be obtained.
[0005]
[Problems to be solved by the invention]
As described above, in the conventional technology, part or all of the liquid refrigerant cooled in the refrigerant circuit is returned to the compression mechanism. Therefore, poor lubrication due to foaming of the liquid refrigerant in the lubricating oil or efficiency due to a useless compression process is improved. There was a decline. Further, as shown in FIG. 6, the method of forming the refrigerant passage in parallel with the refrigerant circuit has a problem that the cooling effect is small because the refrigerant flowing in the refrigerant passage is natural convection.
[0006]
An object of the present invention is to solve the problems of the conventional example described above, and to obtain a large cooling effect without causing poor lubrication and a decrease in efficiency due to a compression process.
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the present invention provides a radiator that cools the refrigerant discharged from the rotary compression mechanism and a refrigerant passage that passes through the lubricating oil reservoir of the hermetic container. When a detection signal reaches a set value by the temperature detection means of the thermistor that is connected between the three-way valve and is in close contact with the rotary compressor, the three-way valve is opened to the refrigerant passage side, and the detection signal is set to the set value. In the following cases, the three-way valve closes the refrigerant passage side, and the refrigerant circulates in the refrigeration cycle.
[0008]
In addition, if the detection signal is equal to or greater than the set value for a certain time, there is a control means for turning off the power to the rotary compressor.
[0009]
[Action]
The present invention provides a low temperature and high pressure liquid refrigerant by a second radiator different from the condenser in the refrigeration cycle for cooling the high temperature and high pressure refrigerant discharged from the rotary compression mechanism, and a lubricating oil reservoir in an airtight container. By exchanging heat with the lubricating oil by the liquid refrigerant in the refrigerant passage that passes through the compressor, it can rotate effectively without impairing the lubrication action of the rotary compressor and without reducing the efficiency in the compression process. The compressor can be cooled.
[0010]
Further, when the detection signal reaches a set value by the temperature detection means of the thermistor in which the three-way valve connected between the radiator and the refrigerant passage is in close contact with the rotary compressor, the three-way valve is If it opens to the refrigerant passage, cools the rotary compressor, and the detection signal is below the set value, the three-way valve closes the refrigerant passage side and circulates in the refrigeration cycle. At this time, the radiator contributes to cooling of the refrigerant together with the condenser in the refrigeration cycle.
[0011]
If the detection signal is equal to or greater than the set value for a certain time, the timer compressor incorporated in the control means turns off the energization of the rotary compressor to prevent overheating of the rotary compressor.
[0012]
【Example】
A cooling device for a rotary compressor according to an embodiment of the present invention will be described below with reference to the drawings.
[0013]
In FIG. 1, reference numeral 1 denotes an airtight container, in which a stator 2 and a rotor 3 of an electric motor section are arranged above the inside, and a compression mechanism 4 that rotates with power from the electric motor is arranged below the stator 2. Has been. The compression mechanism 4 is immersed in the lubricating oil reservoir 5. 6 is below the oil level of the lubricating oil reservoir 5 and enters the inside of the sealed container 1 from the outside of the sealed container 1 to form a refrigerant passage to the outside again.
[0014]
When the rotary compressor 16 having the above configuration passes through the radiator 8 from the discharge pipe 7 and is energized to the solenoid of the three-way valve 9 which switches the refrigerant circuit to the arrow 14 and arrow 13 by energization and de-energization, the refrigerant is arrow 14 constitutes a refrigeration cycle that flows in the direction of 14, passes through the refrigerant passage 6, the condenser 10, the expansion valve 11, and the evaporator 12, and returns to the compressor.
[0015]
Therefore, the discharged refrigerant gas discharged from the compression mechanism 4 passes through the discharge pipe 7 from the sealed container 1 and passes through the radiator 8, the refrigerant passage 6, the condenser 10, the expansion valve 11, and the evaporator 12, and is compressed again. Inhaled by mechanism 4. At this time, the high-temperature and high-pressure discharged refrigerant gas discharged from the compression mechanism 4 is cooled by the radiator 8 to become a low-temperature and high-pressure refrigerant liquid, and heat exchange with the lubricating oil is performed in the refrigerant passage 6. It takes away latent heat of vaporization and becomes a high-temperature and high-pressure refrigerant gas to cool the lubricating oil.
[0016]
The refrigerant flows in the direction of arrow 13 when the solenoid of the three-way valve 9 is not energized. At this time, the radiator 8 contributes to the cooling of the refrigerant together with the condenser 10, and the cooling capacity is expected to increase.
[0017]
Next, the operation of the three-way valve 9 will be described with reference to FIGS. 2 and 3. The temperature detection thermistor 15 shown in FIG. 1 is a temperature detection means of the rotary compressor 16. The outer shell surface is in close contact with the oil surface of the lubricating oil reservoir 5. In FIG. 2, the detection signal of the temperature detection thermistor enters the control unit, and the energization / non-energization of the solenoid of the three-way valve 9 is controlled in the control unit 17 based on the determination of the set value.
[0018]
In FIG. 3, when the detected temperature T of the temperature detection thermistor 15 reaches a set value T ₁ (120 ° C. in this embodiment) in the control unit 17, the solenoid of the three-way valve 9 is energized, and the set value T When it becomes ₂ , it becomes non-energized.
[0019]
Therefore, when the temperature of the rotary compressor 16 is detected temperature T of the temperature sensing thermistor 15 becomes high temperature, reaches a set value T ₁ of the the control unit 17 energizes the solenoid of the three way valve 9, low temperature and high pressure refrigerant Flows in the direction of the arrow 14 and takes away latent heat of vaporization in the refrigerant passage 6 to become high-temperature and high-pressure refrigerant gas, thereby cooling the lubricating oil and lowering the temperature of the rotary compressor 16. When the temperature of the rotary compressor 16 falls and the detected temperature T of the temperature detecting thermistor 15 then reaches the set value T ₂ (110 ° C. in the embodiment) in the control unit 17, the solenoid of the three-way valve 9 Is not energized, and the refrigerant flows in the direction of arrow 13. At this time, the radiator 8 is used together with the condenser 10 for cooling the refrigerant.
[0020]
【The invention's effect】
As is clear from the above description, the present invention cools the high-temperature and high-pressure refrigerant discharged from the rotary compression mechanism to form a low-temperature and high-pressure liquid refrigerant by a second radiator different from the condenser in the refrigeration cycle, By exchanging heat with the lubricating oil by the liquid refrigerant in the refrigerant passage through the lubricating oil reservoir in the sealed container, the efficiency of the compression process can be reduced without impairing the lubricating action of the rotary compressor. The rotary compressor can be effectively cooled without causing it.
[0021]
Further, the temperature of a thermistor in which a three-way valve connected between the radiator and the refrigerant passage is in close contact with the rotary compressor is detected, and the detected temperature becomes higher than a set value. When the three-way valve is opened in the refrigerant passage, the rotary compressor is cooled, and the rotary compressor is not higher than a preset value, the three-way valve closes the refrigerant passage side, and the refrigerant is refrigerated. It flows to the condenser side in the cycle and does not flow to the refrigerant passage.
[0022]
Further, if the overheat state of the rotary compressor continues and the temperature detected by the thermistor is equal to or higher than a set value for a certain time or longer, there is an effect of turning off the energization of the rotary compressor and preventing overheating.
[Brief description of the drawings]
FIG. 1 is a configuration diagram of a refrigeration cycle provided with a cooling device for a rotary compressor in one embodiment of the present invention. FIG. 2 is a block diagram of the device. FIG. 3 is an operation waveform diagram of the device. Cross section of compressor in example [Fig. 5] Configuration diagram of the refrigeration cycle [Fig. 6] Configuration diagram [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Airtight container 2 Stator 3 Rotor 4 Compression mechanism 5 Lubricating oil reservoir 6 Refrigerant passage 7 Discharge pipe 8 Radiator 9 Three-way valve 10 Condenser 11 Expansion valve 12 Evaporator 13 Refrigerant flow 14 Refrigerant flow 15 Thermistor 16 Rotary compressor 17 controller

Claims (1)

A rotary compression mechanism housed in a sealed container, an electric motor that drives the rotary compression mechanism, a discharge pipe that discharges the refrigerant compressed by the rotary compression mechanism to the outside of the sealed container, and the rotary compression formed in the lower part of the sealed container Rotating compressor comprising a lubricating oil reservoir portion in which the mechanism is immersed, and a refrigerant passage disposed in the lubricating oil reservoir portion and having a refrigerant introduced from the outside of the sealed container exchange heat with the lubricating oil and then discharged to the outside of the sealed container A radiator for radiating and cooling the high-temperature and high-pressure refrigerant, a three-way valve for switchingly discharging the refrigerant entered from the refrigerant inlet from the two refrigerant outlets, and a temperature detecting means closely contacting the rotary compressor Control means for controlling the switching of the three-way valve based on the output, and a condenser for cooling the high-temperature and high-pressure refrigerant separately from the radiator, the discharge pipe of the rotary compressor and the three-way valve What is the refrigerant inlet? Refrigeration cycle in which one refrigerant outlet of the three-way valve is connected to the refrigerant inlet of the refrigerant passage, and the other refrigerant outlet is connected to the refrigerant inlet of the condenser together with the refrigerant outlet of the refrigerant passage. The control means causes the refrigerant to flow through the three-way valve to the refrigerant outlet connected to the refrigerant inlet of the refrigerant passage when the output of the temperature detecting means becomes higher than the first set temperature. The rotary compressor is characterized in that it is switched so as to flow to a refrigerant outlet connected to the refrigerant inlet of the condensation note when the temperature falls below a second preset temperature lower than the first preset temperature. Cooling system.

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