JPH0933114A - Refrigerating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a refrigerating device capable of improving the reliability thereof by facilitating the employment of an effective countermeasure even when clogging of an evacuating mechanism due to sludge and the like is generated. SOLUTION: A refrigerating device is constituted of an air conditioner, equipped with a compressor 1, an outdoor heat exchanger 2, an evacuator unit 3 and an outdoor heat exchanger 4 in a refrigerating circuit and employing HFC based refrigerant as the refrigerant therefor while employing synthetic oil, such as ester oil and the like, as refrigerating machine oil. The evacuator unit 3 is constituted of a capillary tube 3 and a motor-driven expansion valve 6, which are connected in parallel. A control unit 18 controls mainly the capillary tube 5 upon normal operation to reduce the pressure of the regrigerant but when the clogging of the capillary tube 5 due to sludge or the like is detected by the change of a discharging refrigerant temperature, the motor- driven expansion valve 6 is controlled mainly to reduce the pressure of the refrigerant.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a refrigerating apparatus using a refrigerating machine oil such as synthetic oil such as ester oil and ether oil having a relatively strong polarity.

[0002]

2. Description of the Related Art A refrigerating apparatus is a refrigerating cycle in which a refrigerant is circulated through a refrigerant circuit having a compressor, a condenser, a pressure reducing mechanism and an evaporator, and the amount of heat absorbed by the evaporator is transferred to the condenser and released. It is what constitutes. And as the refrigerant,
Recently, from the viewpoint of environmental consideration, HFCs such as HFC134a containing hydrofluorocarbon as a main component as an alternative refrigerant to an HCFC refrigerant (for example, HCFC22).
A system refrigerant is used. Further, as the refrigerating machine oil, since mutual solubility with a refrigerant is one of its important characteristics, synthetic oils such as ether oil and ester oil are used for the above HFC-based refrigerants, which may affect the environment. The refrigerating apparatus is configured in consideration of the above.

[0003]

However, since the synthetic oil has a strong polarity, residual impurities other than the refrigerating machine oil and the refrigerant (so-called contaminants), such as cutting oil, rolling oil, and pipe expansion remaining in the refrigerant circuit. It has the property of easily dissolving oil, processing oil, assembly oil, detergent, etc.). Since some of the refrigerating machine oil is discharged from the compressor together with the discharged refrigerant, the above-mentioned residue and the like dissolved according to the refrigerant also flow in the refrigerant circuit. Therefore, in a refrigeration system that uses synthetic oil as refrigeration oil, in the decompression mechanism that is composed of a capillary tube, expansion valve, etc., clogging due to sludge, etc., after the refrigerant has evaporated is likely to occur, which causes abnormalities in the refrigeration cycle. There was a problem of doing. When ester oil is used as the refrigerating machine oil, it hydrolyzes with water to generate a carboxylic acid, and this carboxylic acid reacts with copper to generate copper plating and sludge, so that the pressure reducing mechanism is clogged. There is a problem that is more likely to occur. In particular, the above-described problem becomes serious in a refrigeration system including a capillary tube having an inner diameter of 1.0 mm or less as a decompression mechanism. However, conventional refrigeration systems cannot take effective measures even when the capillary tube is clogged. Therefore, there has been a problem that the malfunction progresses as it is, and finally the function of the device is stopped, which becomes a user complaint.

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object thereof is to take an effective countermeasure even if clogging of sludge or the like occurs in the pressure reducing mechanism. It is to provide a refrigeration system capable of improving its reliability.

[0005]

Therefore, the refrigerating apparatus of claim 1 is provided with a compressor 1, a condenser 2, a pressure reducing mechanism 3 and an evaporator 4 in a refrigerant circuit to form a refrigerating cycle, and ester as refrigerating machine oil. In a refrigerating apparatus using an oil having a relatively strong polarity such as oil or synthetic oil such as ether oil, the pressure reducing mechanism 3 mainly includes a first pressure reducing means 5 configured to reduce the pressure of the refrigerant during normal operation, The second pressure reducing means 6 is designed to mainly reduce the pressure of the refrigerant when an abnormality occurs in the refrigeration cycle due to clogging of sludge or the like generated in the first pressure reducing means 5.
And are connected in parallel with each other.

Whether or not an abnormality has occurred in the refrigeration cycle is determined by any one of the discharge temperature of the compressor, the condensation temperature, the evaporation temperature, the input current, the ambient temperature, the degree of superheat, the degree of supercooling, and the integrated operation time. Depending on the combination, the clogging state of the pressure reducing mechanism can be calculated and monitored.

Further, "when an abnormality occurs in the refrigeration cycle" means
Not only when an abnormality occurs, but also when the first decompression means 5 is clogged and the second decompression means 6 must be operated to eliminate the abnormal state of the refrigeration cycle. Therefore, the case where the abnormal state is eliminated by the operation of the second depressurizing means 6 is also included in the above "at the time of the abnormal state".

In the refrigerating apparatus of the first aspect, even if the first pressure reducing means 5 is clogged, the second pressure reducing means 6 can reduce the pressure of the refrigerant.

Further, the refrigerating apparatus of claim 2 is characterized in that the first depressurizing means is a capillary tube 5 and the second depressurizing means is an electric expansion valve 6.

In the refrigerating apparatus of the second aspect, it is possible to easily implement the refrigerating apparatus.

Further, in the refrigerating apparatus of claim 3, the first depressurizing means is the first capillary tube 11, and the second depressurizing means is a solenoid valve 13 and a second capillary tube 12 connected in series. Is characterized by.

In the refrigerating apparatus of the third aspect, since the depressurizing means is constructed by using the capillary tubes 11 and 12, the cost can be reduced.

The refrigerating apparatus according to a fourth aspect is characterized in that the second capillary tube 12 has a smaller diameter than the first capillary tube.

In the refrigerating apparatus of the fourth aspect, even if the pressure reduction in the second capillary tube 12 is started, it is possible to prevent the pressure reduction amount from changing rapidly.

According to a fifth aspect of the refrigerating apparatus, the first pressure reducing means comprises a first solenoid valve 16 and a first capillary tube 14 connected in series, and the second pressure reducing means is the second solenoid valve 1.
7 and a second capillary tube 15 having a diameter larger than that of the first capillary tube 14 are connected in series. During normal operation, the first solenoid valve 16 is opened and the second solenoid valve 17 is closed. On the other hand, when the abnormality occurs, the first solenoid valve 16 is closed and the second solenoid valve 17 is opened.

In the refrigerating apparatus of the fifth aspect, the second capillary tube 15 is less likely to be clogged than the first capillary tube 14, so that it is possible to avoid further abnormalities.

In the refrigerating apparatus of the sixth aspect, when the second decompression means also becomes clogged with sludge or the like to cause an abnormality in the refrigeration cycle, the first solenoid valve 16 and the second solenoid valve 17 are provided.
Is opened, and the refrigerant is depressurized by both the first depressurizing means and the second depressurizing means.

In the refrigerating apparatus of the above-mentioned claim 6, the second
Even when the pressure reducing means is clogged, the necessary pressure reducing function can be secured with both the first pressure reducing means.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, specific embodiments of the refrigeration apparatus of the present invention will be described in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a refrigerant circuit diagram of an air conditioner according to a first embodiment of the present invention. In this air conditioner, as shown in the figure, a discharge pipe 1a and a suction pipe 1b of a compressor 1 are connected to a four-way switching valve 10, and the four-way switching valve 10 has an outdoor heat exchanger 2 and a pressure reducer. The unit (pressure reducing mechanism) 3 and the indoor heat exchanger 4 are arranged in order of the first gas pipe 19a, the first liquid pipe 19b, the second liquid pipe 19c and the second.
The gas pipes 19d are connected in an annular shape. Here, the decompressor unit 3 includes a capillary tube 5 having an inner diameter of about 1.2 mm or more, which functions as a first decompression unit, and a second decompression unit.
The electric expansion valve 6 functioning as a pressure reducing means is connected in parallel. Further, the discharge pipe 1 of the compressor 1
The thermistor 20 which detects the discharge refrigerant temperature of the compressor 1 is provided in a. In the figure, 18 is a control unit 18 for inputting the discharge refrigerant temperature detected by the thermistor 20 and controlling the pressure reducer unit 3 in accordance with the temperature, which is a micro controller having a CPU, a memory, an input / output interface, and the like. It is configured using a computer. In the figure, 9 is an accumulator provided to prevent liquid compression in the compressor 1, 7 is a liquid shutoff valve, and 8 is a gas shutoff valve, which prevent refrigerant leakage during piping work. It is provided to prevent it. In the air conditioner, H is used as a refrigerant.
In addition to using HFC-based refrigerants such as FC134a, it is possible to use, as the refrigerating machine oil, ether oil or ester oil having relatively strong polarity and good mutual solubility with the HFC-based refrigerant, or synthetic oil such as alkylbenzene oil. .

FIG. 2 is a flowchart showing the operation of the air conditioner configured as described above. First, step S
In 1, normal operation control is performed. That is, in summer or the like, the four-way switching valve 10 is switched to the direction shown by the solid line in FIG. 1 so that the outdoor heat exchanger 2 functions as a condenser, and the indoor heat exchanger 3
While performing the cooling operation by functioning as an evaporator, the four-way switching valve 10 is switched in the direction of the broken line shown in the figure to cause the outdoor heat exchanger 2 to function as an evaporator and the indoor heat exchanger in the winter. 3 is made to function as a condenser, and heating operation is performed. Then, the pressure reduction of the refrigerant in the refrigeration cycle is performed mainly by the capillary tube 5, and the electric expansion valve 6 performs the pressure reduction of the correction amount between the cooling time and the heating time by the opening degree control of the control unit 18. Has become.

Next, in step S2, abnormality diagnosis of the refrigeration cycle is performed. As described above, when a relatively polar oil such as a synthetic oil is used as the refrigerating machine oil, the pressure reducing mechanism in the refrigerant circuit may be clogged with sludge or the like, which causes an abnormality in the refrigeration cycle. Monitoring is performed in step S2. FIG. 3 is a Mollier diagram for explaining an abnormality that occurs in the refrigeration cycle due to clogging of the pressure reducing mechanism. The solid line shows the normal operation, and the broken line shows the abnormal situation. As shown in FIG.
The discharged refrigerant of No. 2 was in the state indicated by the point A during the normal operation, but this has moved to the point B when an abnormality occurs. Since this appears as a sharp rise in the temperature of the discharged refrigerant, monitoring this temperature change makes it possible to detect that the decompression mechanism is clogged and an abnormality has occurred in the refrigeration cycle. . Therefore, in the above air conditioner, the thermistor 20 is provided in the discharge pipe 1a, the temperature of the discharged refrigerant detected by the thermistor 20 is monitored by the control unit 18, and the abnormality diagnosis is executed depending on whether or not a rapid temperature rise occurs. . When it is determined in step S2 that the operation of the refrigeration cycle is normal, the process returns to step S1 and the normal operation is continued.

On the other hand, when the occurrence of an abnormality is detected, the routine proceeds to step S3, the operation of the air conditioner is once stopped, and then the abnormality control is carried out at step S4. That is, based on the determination that it is difficult to normally operate the refrigeration cycle due to clogging of the capillary tube 5 with sludge or the like in step S2, the discharge pipe temperature control using the electric expansion valve 6 and the like will be performed thereafter. The control unit 18 executes the capillary tube substitution control according to the above, and the electric expansion valve 6 mainly performs the pressure reduction of the refrigerant in the refrigeration cycle. In this way, when the capillary tube 5 is clogged with sludge or the like and the refrigeration cycle becomes abnormal, the decompression function can be ensured by the alternative operation by the electric expansion valve 6, whereby the air conditioner is provided. Has a fail-safe function. Therefore, when an abnormality occurs, the conventional drawback that the device must be left as it is until it stops functioning is solved, and thereby it is possible to improve the reliability of the device and customer satisfaction. Has become.

By the way, the degree of clogging of the capillary tube 5 which causes an abnormality in the refrigeration cycle is not constant,
It may also increase or decrease after an abnormality occurs. Even when clogging occurs, some of the refrigerant flows through the capillary tube 5. Therefore, it is desirable that the refrigerant be circulated by the second pressure reducing means according to the degree of clogging of the capillary tube 5. . Therefore, in the above air conditioner, the second pressure reducing means is constituted by the electric expansion valve 6 so that the pressure reducing unit 3 as a whole can exhibit an appropriate pressure reducing function by the capillary tube alternative control such as the discharge pipe temperature control. .

Further, in the above air conditioner, the presence or absence of abnormality is judged by the rise of the discharge pipe temperature.
As shown in the Mollier diagram, the compressor input current increases (see C in the figure), the condensation temperature rises, the evaporation temperature falls, the ambient temperature, the degree of superheat, the degree of supercooling rises, and the cumulative operation time, Alternatively, it can be determined by various combinations thereof.

(Second Embodiment) FIG. 4 shows a second embodiment of the present invention.
It is a partial refrigerant circuit diagram showing decompressor unit 3 used for an air harmony machine which is an embodiment. In this depressurizer unit 3, the first depressurizing means is constituted by the first capillary tube 11, while the second depressurizing means is constituted by connecting the solenoid valve 13 and the second capillary tube 12 in series, and the second capillary tube. The diameter 12 is smaller than that of the first capillary tube 11. The configuration of the other parts of the refrigerant circuit is the same as the first
The description is omitted here because it is the same as the embodiment.

The air conditioner of the second embodiment also operates according to the flowchart of FIG. In step S1, normal operation control is performed, and this is continued until an abnormality in the refrigeration cycle is detected in step S2.
In this normal operation control, the solenoid valve 13 is closed by the control unit 18, that is, in the shut-off state. Therefore, the pressure reduction of the refrigerant is performed by the first capillary tube 11. Then, in step S4, where the abnormality is detected after the abnormality is detected in step S2, the abnormal time control is executed. In the abnormal time control, the solenoid valve 13 is opened by the control unit 18, that is, in the communication state. Then, the pressure reduction of the refrigerant is mainly performed by the second capillary tube 12. At this time, some refrigerant normally flows through the clogged first capillary tube 11, but since the second capillary tube 12 has a smaller diameter than the first capillary tube 11, the solenoid valve 13 is used.
By opening the valve, the state of the refrigeration cycle is not changed suddenly. Then, due to both the clogged first capillary tube 11 and the second capillary tube 12 having a small diameter, the decompressor unit 3 is operated during normal operation.
Since it is possible to exhibit a function substantially equivalent to the decompression function possessed by, it is possible to continue more appropriate operation. Further, since the second pressure reducing means is composed of the relatively inexpensive solenoid valve 13 and the capillary tube 12, the cost can be reduced.

(Third Embodiment) FIG. 5 shows a third embodiment of the present invention.
It is a partial refrigerant circuit diagram showing decompressor unit 3 used for an air harmony machine which is an embodiment. In this depressurizer unit 3, the first depressurizing means is connected to the first capillary tube 14 and the first capillary tube 14.
The second pressure reducing means is configured by connecting the second capillary tube 15 and the first solenoid valve 17 in series, while the solenoid valve 16 is connected in series, and the second capillary tube 12 is configured by the first capillary tube 12. It has a larger diameter than the tube 11. The configuration of the other parts of the refrigerant circuit is the same as that of the first embodiment, and the description thereof is omitted here.

The air conditioner of the third embodiment also operates according to the flowchart of FIG. In step S1, normal operation control is performed. This is continued until an abnormality in the refrigeration cycle is detected in step S2.
In this normal operation, the controller 18 controls the first
The solenoid valve 16 is opened, while the second solenoid valve 17 is closed. Therefore, the pressure of the refrigerant is reduced by the first capillary tube 1
4 is performed. Then, in step S4, in which the abnormality is detected in step S2, the abnormal time control is executed. In this abnormal time control, the control unit 18 closes the first electromagnetic valve 16 while the second electromagnetic valve 16 is closed. Valve 17
Is opened. Therefore, the pressure reduction of the refrigerant is performed by the second capillary tube 15. Since the second capillary tube 15 has a larger diameter than the first capillary tube 14, even when clogging of sludge or the like occurs in the first capillary tube 14, the clogging can be avoided in the second capillary tube 15 in some cases. Many.
Therefore, it is possible to further reduce the probability that a defect will occur thereafter, thereby improving the reliability of the device. The second capillary tube 15 has a larger diameter than the first capillary tube 14, but when the second solenoid valve 15 is opened, the first solenoid valve 14 is closed and the first solenoid valve 14 is closed.
Since the circulation of the refrigerant does not occur in the capillary tube 14, the state of the refrigeration cycle does not differ greatly from that during normal operation. By the way, when the second capillary tube 15 is also clogged with sludge or the like during the abnormal operation control, which causes an abnormality in the refrigeration cycle and is detected, the control unit 18 opens the first electromagnetic valve 16. Take control. Then both capillary tubes 14, 1
The sum of some of the refrigerant flowing through 5 allows the normal functioning of the refrigeration cycle to be maintained. In this case, since the air conditioner having the three-stage fail-safe function can be configured, the reliability can be further improved and the customer satisfaction can be further improved.

Although the specific embodiments of the present invention have been described above, the present invention is not limited to the above embodiments, and can be implemented with various modifications within the scope of the present invention. For example, as a modification of the decompressor unit 3 of the first embodiment, the configuration shown in FIG. 6 may be used. In this example, the first pressure reducing means is configured by connecting in series a capillary tube 5a provided with a check valve 5b in parallel and another capillary tube 5b. With such a configuration, the first pressure reducing means can adjust the amount of pressure reduction during cooling and during heating, and the control of the electric expansion valve 6 can be eliminated during normal operation control. Further, as shown in FIG. 7, the depressurizer unit 3 may be used in combination with the diversion capillary tubes 21 ... In series.

[0031]

According to the refrigerating apparatus of the first aspect, the refrigerant can be depressurized by the second depressurizing means even if the first depressurizing means is clogged, so that the reliability of the apparatus is improved and the customer satisfaction is improved. It becomes possible to improve.

Further, in the refrigerating apparatus of the second aspect, it is possible to facilitate the implementation.

Further, in the refrigerating apparatus of the third aspect, since the pressure reducing means are both constructed by using the capillary tube,
Costs can be reduced.

In the refrigerating apparatus according to the fourth aspect, even if the pressure reduction in the second capillary tube is started, it is possible to avoid a rapid change in the pressure reduction amount.

In the refrigerating apparatus of the fifth aspect, the second capillary tube is less likely to be clogged than the first capillary tube, and therefore it is possible to avoid further occurrence of abnormality.

In the refrigerating apparatus according to the sixth aspect, the necessary pressure reducing function can be ensured by both the first pressure reducing means and the second pressure reducing means even when the second pressure reducing means is clogged. Can be further improved.

[Brief description of drawings]

FIG. 1 is a refrigerant circuit diagram of an air conditioner that is a first embodiment of the present invention.

FIG. 2 is an operation flowchart of the air conditioner.

FIG. 3 is a Mollier diagram of the air conditioner, in which the solid line indicates normal operation and the broken line indicates abnormality.

FIG. 4 is a partial refrigerant circuit diagram showing a pressure reducer unit used in an air conditioner according to a second embodiment of the present invention.

FIG. 5 is a partial refrigerant circuit diagram showing a pressure reducer unit used in an air conditioner according to a third embodiment of the present invention.

FIG. 6 is a modification of the pressure reducer unit according to the first embodiment.

FIG. 7 is a modification of the pressure reducer unit according to the first embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Compressor 2 Outdoor heat exchanger 3 Decompressor unit 4 Indoor heat exchanger 5 Capillary tube 6 Electric expansion valve 11 1st capillary tube 12 2nd capillary tube 13 Solenoid valve 14 1st capillary tube 15 2nd capillary tube 16th 1 solenoid valve 17 second solenoid valve

Claims (6)

[Claims] 1. A refrigeration cycle comprising a compressor (1), a condenser (2), a decompression mechanism (3) and an evaporator (4) in a refrigerant circuit to form a refrigerating machine oil such as ester oil and ether oil. In a refrigerating apparatus using an oil having a relatively strong polarity such as the synthetic oil described above, the pressure reducing mechanism (3) mainly includes a first pressure reducing means (5) for reducing the pressure of the refrigerant during normal operation, and A second pressure reducing means (6) for mainly reducing the pressure of the refrigerant when an abnormality occurs in the refrigeration cycle due to clogging of sludge or the like generated in the first pressure reducing means (5),
A refrigeration apparatus configured by connecting in parallel with each other. 2. The refrigerating apparatus according to claim 1, wherein the first depressurizing means is a capillary tube (5) and the second depressurizing means is an electric expansion valve (6). 3. The first pressure reducing means is a first capillary tube (11), and the second pressure reducing means is a solenoid valve (13) and a second capillary tube (12) connected in series. The refrigeration system according to claim 1, which is characterized in that. 4. The second capillary tube (12)
The refrigerating apparatus according to claim 3, wherein the diameter is smaller than that of the first capillary tube. 5. The first pressure reducing means is a first solenoid valve (16).
And a first capillary tube (14) are connected in series, and the second decompression means has a diameter larger than that of the second solenoid valve (17) and the first capillary tube (14).
A capillary tube (15) is connected in series, and during normal operation, the first solenoid valve (16) is opened and the second solenoid valve (17) is closed, while when the abnormality occurs, the first solenoid valve (16) is closed. The refrigeration system according to claim 1, wherein the first solenoid valve (16) is closed and the second solenoid valve (17) is opened. 6. The first solenoid valve (16) and the second solenoid valve (17) are opened together when the second decompression means is clogged with sludge or the like and an abnormality occurs in the refrigeration cycle. The refrigerating apparatus according to claim 5, wherein the refrigerant is depressurized by both the first depressurizing means and the second depressurizing means.