JP2002181420A - Compression refrigerating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compression refrigerating apparatus, in which a refrigerant of poor water-absorption property and a lubricating oil of good water-absorption property are used in combination, and amount of water content mixed in a lubricating oil can be detected very accurately without causing thermal damage to a moisture indicator. SOLUTION: In the compression refrigerating apparatus, heat exchangers (26, 40) for dropping temperature of the lubricating oil and a moisture indicator (28) for detecting content of water mixed in the lubricating oil are provided in a lubricating oil line (L3) for flowing lubricating oil separated in an oil separator (14). The heat exchangers (26, 40) are placed in the region nearer to the oil separator (14) than the moisture indicator (28).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compression refrigeration apparatus, and more particularly, to a technique for controlling moisture mixed in lubricating oil of a compression refrigeration apparatus.

[0002]

2. Description of the Related Art In FIG. 9, a conventional compression refrigeration system generally designated by reference numeral 1 has a compressor 2 and an oil separator 3. In the compressor 2, the gas-phase refrigerant containing the lubricating oil is compressed and discharged to the oil separator 3 via a line L1 (a line in which a solid line and a dotted line are parallel in the figure). , Separating the gaseous refrigerant and the lubricating oil. The separated gas-phase refrigerant flows through a refrigerant line L2 (line indicated by a solid line in the figure), is condensed by a condenser 4 and a cooling fan 4F, flows into a dryer 6 via a liquid receiver 5, and is operated during operation. Moisture mixed into the refrigerant is removed.

[0003] The liquid-phase refrigerant from which moisture has been removed by the dryer 6 flows through the moisture indicator 7 and the moisture content in the refrigerant is detected. The evaporator 9 is supplied to the evaporator 9 via the expansion valve 8 and removes the heat of evaporation in combination with the air blown by the fan 9F.

On the other hand, the lubricating oil separated in the oil separator 3 merges with the gas-phase refrigerant flowing through the refrigerant line L2 at the junction B via the lubricating oil line L3 and the pressure reducing device DP. The gas-phase refrigerant that has joined at the junction B and mixed with the lubricating oil flows through a line L4 (a line in which the solid line and the dotted line are parallel in the drawing) and communicates with the suction port of the compressor 12.

[0005] Here, no moisture indicator is provided in the lubricating oil line L3, but only in the refrigerant line L2. The refrigerant used in the conventional compression refrigeration system 1 (for example, HCFC22: molecular formula CHF2C
1) has relatively good water absorption. On the other hand, as the lubricating oil used in the conventional compression refrigeration system 1, a lubricant having poor water absorption (for example, mineral oil) is often used. Therefore, regarding the absorption of moisture, the influence of the refrigerant is dominant,
There was no problem if a moisture indicator was provided in the refrigerant line L2 to detect the amount of water mixed in the refrigerant.

However, the refrigerant used in the conventional compression refrigeration system 1 (for example, HCFC22: molecular type CHF2)
In Cl), lubricating oils with much better water absorption than refrigerants may be used (eg PAG: polyalkylene glycol). In recent years, a so-called “new refrigerant” (for example, HFC134a:
When the molecular formula C2H2F4) is used,
Lubricating oils with much better water absorption than refrigerants (eg PAG, POE (polyol ester), PVE
(Polyvinyl ether) and the like. When a lubricating oil having good water absorption is used, a moisture indicator is provided only in the refrigerant line, and merely detecting the amount of water mixed in the refrigerant is not enough to cope with the behavior of the mixed water. It is. In particular, water mixed in the lubricating oil causes various problems such as icing, deterioration of the lubricating oil, sludge formation and corrosion, etc. This is essential in a compression refrigeration system using a lubricating oil having good properties.

However, in the prior art, it is difficult to detect moisture mixed in lubricating oil in a compression refrigeration system using lubricating oil having good water absorption.

As another conventional technique, for example, in Japanese Patent Application Laid-Open No. 07-019611, a moisture indicator is provided in the oil separator 3 (or oil reservoir) to detect the amount of moisture mixed in the lubricating oil. Is disclosed.

However, according to the prior art, since the oil separator 3 is disposed near the discharge port of the compressor 2, the temperature of the oil stored therein is high. And, since the moisture indicator generally has not so high heat resistance, when it is disposed in the oil separator 3, it is thermally damaged due to the amount of heat held by the lubricating oil. Further, as a detection characteristic of the moisture indicator, there is a problem that the sensitivity becomes lower as the temperature becomes higher, and it is difficult to detect the amount of mixed water with high accuracy.

[0010]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above-mentioned problems of the prior art, and has been proposed in a compression refrigeration system using a lubricating oil having good water absorption. Provide a compression refrigeration system that can grasp the amount of water, prevent thermal damage to the moisture indicator, and detect the amount of water mixed with high accuracy. The purpose is.

The compression refrigeration system of the present invention comprises an oil separator (1).
Lubricating oil line (L3) through which the lubricating oil separated in 4) flows
In addition, a heat exchanger (26, 40) for lowering the temperature of the lubricating oil and a moisture indicator (28) for detecting the content of moisture mixed in the lubricating oil are interposed.
6, 40) are arranged in a region closer to the oil separator (14) than the moisture indicator (28) (Claim 1: FIGS. 1 to 7).

According to the present invention having such a configuration, since the moisture indicator is interposed in the lubricating oil line, in the case of a compression refrigerator using a lubricating oil having good water absorption (for example, PAG). As described above, even if the amount of moisture absorption of the lubricating oil is dominant, the water content of the lubricating oil can be accurately detected.

[0013] Here, since the heat exchanger is disposed in a region closer to the oil separator than the moisture indicator, the lubricating oil separated by the oil separator is heated before flowing through the moisture indicator. Cooled by exchanger.
Therefore, the moisture indicator can be protected from thermal damage. Also, since the lubricating oil is cooled, the temperature of the installation location of the moisture indicator also decreases, so that the moisture indicator is installed under a highly sensitive measurement atmosphere, and the detection of the water content in the lubricating oil is performed with high accuracy. You can do it.

In carrying out the present invention, the heat exchanger (2)
Preferably, 6) is an air heat exchanger for dissipating the amount of heat held by the lubricating oil into the atmosphere (Claim 2: FIGS. 1, 3,
(Fig. 4).

Alternatively, the heat exchanger (40) is configured to exchange heat between the refrigerant passing through the evaporator (24) interposed in the refrigerant line (L2) and the lubricating oil. It is preferable (Claim 3: FIGS. 2, 6 and 7).

Here, the lubricating oil line (L3) is provided with a heat exchanger (26, 40) and a moisture indicator (2).
8) Dryer (4) to remove water mixed in lubricating oil
2) a first line (L3-1) interposed, a heat exchanger (26, 40), a moisture indicator (28),
Bypass line (L3) that bypasses the dryer (42)
-2) (B1) is preferable (Claim 4: FIGS. 3, 4, 6, and 7).

In the case where such a structure is provided, a dryer for removing water is also provided in the lubricating oil line, and when the water is mainly absorbed by the lubricating oil, the water mixed in the lubricating oil is efficiently removed. You. In addition, when the compression refrigeration system is used for a heating operation, if the entire amount of the lubricating oil separated by the oil separator is cooled by the heat exchanger (particularly, the air heat exchanger 26), the amount of heat held by the lubricating oil can be reduced. They will be discarded, resulting in a decrease in heating efficiency. However, if the above-described configuration is adopted, since the amount of heat held by the lubricating oil is not discarded by flowing the lubricating oil through the bypass line, it is possible to cope with the above-described decrease in efficiency during heating.

In the case where the above configuration is adopted, the first line (L3-1) and the bypass line (L3-
2) is provided with a three-way switching valve (three-way valve: V1) at the branch (B1), and the three-way switching valve (V1)
Is during cooling operation (step S1 in FIG. 5 is “cooling”) or heating operation (step S1 in FIG. 5 is “heating”) and before a predetermined time has elapsed from the start of operation (step S4).
At the stage of (NO), the bypass line (L3-2) is closed and the lubricating oil flows to the line (L3-1) side where the heat exchangers (26, 40) and the dryer (42) are interposed. Opening and closing control is performed (step S6 or S3), and after a predetermined time has elapsed from the start of the heating operation (at the time of steady operation: step S
4 is YES), the lubricating oil is supplied to the bypass line (L
It is preferable that opening and closing control (step S5) is performed so as to flow through 3-2) (Claim 5: FIGS. 5, 4, and 7).

The operation method of the compression refrigeration system having the above configuration is as follows.
A step of determining whether the operation is a cooling operation or a heating operation (FIG. 5: step S1), and a step of measuring whether a required time has elapsed from the start of the operation in the case of the heating operation (step S4). During the cooling operation (step S1 in FIG. 5 is “cooling”) or during the heating operation (step S1 in FIG. 5 is “heating”) and before a predetermined time elapses from the start of operation (NO in step S4). In step (3), the bypass line (L3-2) is closed and the opening / closing control is performed so that the lubricating oil flows to the line (L3-1) in which the heat exchangers (26, 40) and the dryer (42) are interposed. At the step (step S6 or S3) and after a predetermined time has elapsed from the start of the heating operation (at the time of steady operation: step S4 is YES), the opening and closing control is performed so that the lubricating oil flows through the bypass line (L3-2). Process (Step S ), And a city (claim 7: 5, 4, 7).

According to the above-described compression refrigeration apparatus or its operation method, in a compression refrigeration apparatus capable of switching between a cooling operation and a heating operation, the compression refrigeration system is mixed with the lubricating oil while maintaining the operation efficiency at a high level. Water can be removed, that is, during the heating operation (at the time of steady operation), the entire amount of the lubricating oil is not cooled by the air heat exchanger, so that a decrease in the heating efficiency is prevented. On the other hand, during cooling, the effect on cooling efficiency is negligible, so that most of the lubricating oil flows to the heat exchanger side in order to lower the lubricating oil temperature.

Further, according to the above-described compression refrigeration apparatus and operating method, a predetermined time (for example, 1
During (time), the entire amount of the lubricating oil flows through the line on the side where the dryer is interposed, and the water mixed with the lubricating oil is removed. After the predetermined time has elapsed and the steady operation state has been reached, most of the lubricating oil flows through the bypass line and bypasses the heat exchanger, so that a decrease in heating efficiency due to cooling of the lubricating oil is prevented.
In this way, it is possible to meet the conflicting demands of removing moisture mixed in the lubricating oil and preventing a decrease in the heating efficiency.

In addition, the compression refrigeration system of the present invention has a moisture indicator (28) interposed in the lubricating oil line (L3) through which the lubricating oil separated by the oil separator (14) flows. The moisture indicator (28) is configured to detect the content of water mixed in the lubricating oil, and the compressor (1) compresses the refrigerant mixed with the lubricating oil.
A heat exchanger (46) is interposed in the line (L1) connecting the 2) and the oil separator (14), and the heat exchanger (46)
Is a refrigerant discharged from the compressor and mixed with lubricating oil,
It is configured to exchange heat with the heat medium flowing through the line (L5) communicating with the thermal load (G) (claim 6: FIG. 8).

In the compression refrigeration apparatus of the present invention having such a configuration, even when the amount of moisture absorption of the lubricating oil is dominant, as in the case of using a lubricating oil having good water absorption, the lubricating oil The water content can be accurately detected. In addition, the amount of heat held by the refrigerant discharged from the compressor (mixed with the lubricating oil) is supplied to the heat medium flowing through the line communicating with the thermal load via the heat exchanger. The temperature is lowered. As a result, the moisture indicator is not thermally damaged, and in a highly sensitive measurement atmosphere,
The detection of the water content in the lubricating oil can be performed with high accuracy.

The refrigerant condenses in the oil separator (14),
In order to prevent the liquid-phase refrigerant from being sucked into the compressor, the amount of heat exchange by the heat exchanger or the flow rate of the heat medium flowing through the line communicating with the thermal load is preferably adjusted as appropriate.

[0025]

Embodiments of the present invention will be described below with reference to the accompanying drawings. In the drawings, similar members are denoted by similar reference numerals.

FIG. 1 shows a first embodiment of the present invention. In FIG. 1, a compression refrigeration apparatus generally denoted by reference numeral 10 has a compressor 12 and an oil separator 14. The compressor 12 compresses the gas-phase refrigerant containing the lubricating oil and compresses the oil via a line L1 (line in which the gas-phase refrigerant containing the lubricating oil flows: a line in which a solid line and a dotted line are parallel in the figure). Discharge to the separator 14. And in the oil separator 14,
The compressed mixture of the gas-phase refrigerant and the lubricating oil is separated into the gas-phase refrigerant and the lubricating oil.

[0027] The separated gas-phase refrigerant is supplied to a refrigerant line L2.
(Indicated by a solid line in the figure), and is condensed by the condenser 16. The liquid-phase refrigerant condensed in the condenser 16 is supplied to the receiver 1
The water flows into the dryer 20 through 8 and water (water mixed into the refrigerant during operation) is removed.

The liquid-phase refrigerant from which the moisture has been removed by the dryer 20 is supplied to the evaporator 24 via the expansion valve 22, and takes the heat of evaporation to become a gas-phase refrigerant. At that time, the area where the evaporator 24 is installed is cooled or cooled by the amount of heat of evaporation. The gas-phase refrigerant evaporated by the evaporator 24 joins a lubricating oil flowing through a lubricating oil line L3 described later at a junction B.

In the oil separator 14 again, the separated lubricating oil (from the gas-phase refrigerant) flows through a lubricating oil line L3 (shown by a dotted line in the figure), and after being cooled by the air heat exchanger 26, the moisture indicator 28, the water content in the lubricating oil (the amount of water contained in the lubricating oil) is detected.

The lubricating oil whose moisture content is detected by the moisture indicator 28 passes through the pressure reducing device 30 and then flows through the refrigerant line L2 at the junction B (a gas-phase refrigerant at the junction B) as described above. To join. In other words, the refrigerant line L2 and the lubricating oil line L3 merge at the junction B, and the gas-phase refrigerant mixed with the lubricating oil flows through the line L4 (the line in which the solid line and the dotted line are parallel in the figure). It communicates with the suction port of the compressor 12.

Here, reference numeral 32 denotes a cooling device provided for cooling the condenser 16 interposed in the refrigerant line L2 and for cooling the air heat exchanger 26 interposed in the lubricating oil line L3. Indicates a fan. Similarly, reference numeral 34 denotes a fan for promoting heat exchange between the air and the liquid-phase refrigerant in the evaporator 24.

According to the first embodiment shown in FIG. 1, a moisture indicator 28 for detecting the water content is provided in the line L3 through which only the lubricating oil flows. Therefore, a refrigerant having poor water absorption (for example, a so-called “new refrigerant”: for example, H
Even if the amount of moisture absorption of the lubricating oil is dominant, as in the case of a compression refrigerator using a combination of FC134Cl (molecular formula C2H2F4) and a lubricating oil having good water absorption (eg, PAG), the lubricating oil Can be accurately detected.

Here, the lubricating oil separated by the oil separator 14 is cooled by the air heat exchanger 26 (and the cooling fan 32) before flowing through the moisture indicator 28. Can be protected from mechanical damage. At the same time, the moisture indicator 28 can be installed in a highly sensitive measurement atmosphere to detect the moisture content in the lubricating oil with high accuracy.

FIG. 2 shows a second embodiment of the present invention. In the first embodiment of FIG. 1, the lubricating oil is cooled by the air heat exchanger 26 (and the cooling fan 32) before flowing through the moisture indicator 28. In contrast, in the compression refrigeration apparatus 10A according to the second embodiment of FIG.
0 is between the refrigerant flowing between the evaporator 24 of the line L2 (refrigerant line) and the junction B and the lubricating oil separated by the oil separator 14 and flowing through the line L3 (lubricating oil line). ,
It is configured to perform heat exchange.

In other words, in the embodiment of FIG.
The lubricating oil flowing through 3 releases its retained heat into the air (via the air heat exchanger 26). On the other hand, in the embodiment of FIG. 2, the amount of heat retained by the lubricating oil flowing through the line L3 is supplied to the refrigerant flowing between the evaporator 24 and the junction B of the refrigerant line L2, and the evaporator 24 is turned off. Even if there is a liquid phase state in the passed refrigerant, it is surely evaporated (vaporized) and only the gas phase refrigerant is supplied to the compressor 12. With such a configuration, in the embodiment of FIG. 2, the liquid-phase refrigerant or the gas-liquid two-phase refrigerant is sucked into the compressor 12 to prevent the compressor 12 from being damaged.

In addition, as in the case of FIG. 1, when the amount of moisture absorption of the lubricating oil is dominant, the moisture content of the lubricating oil can be accurately detected, and the moisture indicator 28 is thermally damaged. Can be protected from
In addition, the moisture content can be detected by the moisture indicator 28 with high accuracy.

In other respects, the configuration and the operation and effect are the same as those of the first embodiment shown in FIG. 1 in the second embodiment shown in FIG.

FIG. 3 shows a third embodiment of the present invention. The compression refrigeration apparatus 10B of FIG. 3 has substantially the same configuration as the compression refrigeration apparatus 10 shown in FIG.

However, the compression refrigeration system 10B of FIG.
In relation to the lubricating oil line L3, the configuration is different from the embodiment of FIG. In FIG. 3, in the compression refrigeration apparatus 10B according to the third embodiment, the lubricating oil line L3 through which the lubricating oil separated by the oil separator 14 flows is connected to the first branch point B1.
To branch to lines L3-1 and L3-2.

The line L3-1 includes an air heat exchanger 26,
In addition to the moisture indicator 28, a dryer 42 for removing moisture mixed in the lubricating oil is provided. Here, the air heat exchanger 26 and the moisture indicator 28 have the same configuration as that of the first embodiment in FIG. That is, the air heat exchanger 26 is cooled by the cooling fan 32, and functions to protect the moisture indicator 28 from thermal damage and to maintain the sensitivity of the moisture indicator 28 at a high level.

The reason why the moisture indicator 28 is arranged downstream of the dryer 42 (closer to the junctions B and B2) is to detect the moisture concentration (in the lubricating oil) after the moisture is absorbed by the dryer 42. To do that.

On the other hand, the line L3-2 is connected to the air heat exchanger 2
6. It is configured as a bypass line that bypasses the moisture indicator 28 and the dryer 42. At the time of heating, cooling the entire amount of the lubricating oil separated by the oil separator 14 with the air heat exchanger 26 results in discarding the amount of heat held by the lubricating oil outside the system of the compression refrigeration apparatus 10B. This causes a decrease in the heating efficiency. Line L3-
2 is provided to cope with such a decrease in efficiency during heating.

The line L3-1 and the line L3-2 join at a junction B2 to form a lubricating oil line L3-3. The lubricating oil line L3-3 is connected to the refrigerant line L2 via the pressure reducing device 30. It reaches junction B.

According to the compression refrigeration system 10B of FIG. 3 according to the third embodiment, the lubricating oil line (L3-1) is also provided with the drier 42 for removing moisture, so that moisture is mainly contained in the lubricating oil. When absorbed, the mixed water is efficiently removed. Further, since the dryer 42 is provided on the downstream side of the air heat exchanger 26 (on the merging point B2, B side), the moisture mixed with the lubricating oil is condensed when passing through the air heat exchanger 26. Since it is in the liquid phase, it is efficiently removed by the dryer 42.

Other configurations and operational effects are the same as those of the third embodiment shown in FIG. 3 and the second embodiment shown in FIGS.

FIGS. 4 and 5 show a fourth embodiment of the present invention. In FIG. 4, a compression refrigeration apparatus generally indicated by reference numeral 10C is a compression refrigeration apparatus 1 according to the third embodiment of FIG.
0B. However, in the compression refrigeration apparatus 10C of FIG. 4, a three-way valve V1 (three-way switching valve) is interposed at a branch point B1 of the lubricating oil line L3, and the three-way valve V1 is provided with a signal from a control unit (control unit) CU. It is different from the embodiment of FIG. 3 in that the opening and closing are controlled via the transmission line CL-1.

Under the control of the control device 44, in the compression refrigeration system 10C of FIG. 4, the compression refrigeration system 10C capable of switching between the cooling operation and the heating operation maintains the lubrication while maintaining the operation efficiency at a high level. It is possible to remove the water mixed in the oil.

Next, referring also to FIG. 5, the first branch point B
1 will be described. As described above, when the entire amount of the lubricating oil is cooled by the air heat exchanger 26 during the heating operation, the heating efficiency decreases.
On the other hand, at the time of cooling, it is preferable that the lubricating oil temperature be lower in order to improve the cooling efficiency. As described above, regarding the temperature of the lubricating oil, the necessity of cooling the lubricating oil differs between heating and cooling. Therefore, also in the opening / closing control of the three-way valve V1, it is first determined whether the compression refrigeration apparatus 10C is used for the heating operation or for the cooling operation (FIG. 5: step S1).

If the compression refrigeration system 10C is to be used for heating, the operation of the compression refrigeration system 10C is started (step S2). When the operation of the compression refrigeration apparatus 10C is started, first, the three-way valve V1 is controlled so that the lubricating oil does not flow through the bypass line L3-2 and the entire amount flows through the line L3-1 (step S3). .

Then, while maintaining the three-way valve V1 in that state, it is determined whether or not a predetermined time (for example, one hour: case-by-case) has elapsed from the start of operation (step S4). If the predetermined time has not elapsed from the start of the operation and the compression refrigeration apparatus 10C is in a stage before reaching the steady operation state (NO in step S4), the state in step S3;
That is, the lubricating oil does not flow through the bypass line L3-2,
The state where the whole amount flows through the line L3-1 is maintained (step S4 is a NO loop).

When a predetermined time has elapsed from the start of operation (YES in step S4), and the compression refrigeration system 10C reaches a steady operation state, the three-way valve V1 is switched so that most of the lubricating oil passes through the bypass line L3-2. Let it flow (step S5: normal heating operation).

As described above, during the heating operation, it is desirable not to cool the lubricating oil in order to improve the heating efficiency.
However, if the entire amount of the lubricating oil is configured to always flow through the bypass line L3-2 during heating, the lubricating oil does not flow through the dryer 42 interposed in the line L3-1, and thus is mixed with the lubricating oil. It will not be possible to remove the water that has drained.

In contrast, steps S1-S5 in FIG.
Is performed, the entire amount of the lubricating oil flows through the line L3-1 for a predetermined time (for example, one hour) immediately after the start of the operation, and the moisture mixed in the dryer 42 is removed. After the predetermined time elapses and the compression refrigeration system 10C enters a steady operation state, the lubricating oil mostly flows through the bypass line L3-2 and bypasses the air heat exchanger 26. This prevents the heating efficiency from being lowered. This makes it possible to meet conflicting demands for removing moisture mixed in the lubricating oil and preventing a decrease in heating efficiency.

In step S1 again, when the compression refrigeration system 10C is used in the cooling operation, the cooling efficiency is improved by cooling the lubricating oil, so that the lubricating oil does not flow through the bypass line L3-2. Next, the three-way valve V1 is controlled so that most of it flows through the air heat exchanger 26 (step S6). Therefore, during the cooling operation, the lubricating oil is always cooled by the action of the air heat exchanger 26 and the cooling fan 32, and the moisture mixed in by the dryer 42 is always removed.

The other configurations and operational effects of the fourth embodiment shown in FIGS. 4 and 5 are the same as those of the embodiment shown in FIGS.

FIG. 6 shows a fifth embodiment of the present invention. The compression refrigeration apparatus 10D according to this embodiment has the configuration shown in FIG.
The configuration is substantially the same as that of the compression refrigeration apparatus 10A according to the embodiment. However, the compression refrigeration system 10D of FIG.
The lubricating oil line L3 through which the lubricating oil separated by the oil separator 14 flows is divided into lines L3-1 and L3-2 at a branch point B1.
To the lubricating oil line L3-3 at the junction B2.
This is different from the compression refrigeration apparatus 10A in FIG.

In FIG. 5, the lubricating oil line L3 is
At the branch point B1 of FIG.

The line L3-1 is provided with a heat exchanger 40, a moisture indicator 28, and a dryer 42 for removing moisture mixed in the lubricating oil. Here, the heat exchanger 40 includes a refrigerant flowing between the evaporator 24 of the line L2 (refrigerant line) and the junction B, and a lubricating oil line (L3, L3-1, L3-2, L3-3). It is configured to perform heat exchange with the lubricating oil flowing through.

That is, when the lubricating oil passes through the heat exchanger 40, the amount of heat stored in the lubricating oil is injected into the refrigerant to lower the temperature, so that the moisture indicator 28 can be protected from thermal damage, and the moisture indicator can be protected. 28 can be maintained at a high level.

On the other hand, the line L3-2 is connected to the heat exchanger 40,
The moisture indicator 28 is configured as a bypass line that bypasses the dryer 42. At the time of heating, when the entire amount of the lubricating oil separated by the oil separator 14 is cooled by the heat exchanger 40, the amount of heat held by the lubricating oil is discarded, thereby lowering the heating efficiency. The line L3-2 is provided to cope with such a decrease in efficiency during heating.

The line L3-1 and the line L3-2 join at a junction B2 to form a lubricating oil line L3-3. The lubricating oil line L3-3 is connected to the refrigerant line L2 via the pressure reducing device 30. It reaches junction B.

According to the compression refrigeration system 10D of FIG. 6, the lubricating oil line (L3-1) also has a dryer 42 for removing moisture.
Is provided, the mixed water is efficiently removed especially when the water is mainly absorbed by the lubricating oil.
Further, since the dryer 42 is provided on the downstream side of the heat exchanger 40 (on the merging point B2, B side), the moisture mixed with the lubricating oil is condensed when passing through the heat exchanger 40 and becomes liquid. Since they are in a phase, they are efficiently removed by the dryer 42.

Other configurations and operational effects are the same as those of the fifth embodiment shown in FIG. 6 in the fifth embodiment shown in FIGS.

FIG. 7 shows a sixth embodiment of the present invention. In FIG. 7, a compression refrigeration apparatus generally denoted by reference numeral 10E is a compression refrigeration apparatus 10D according to the fifth embodiment of FIG.
And have substantially the same configuration. However, in the compression refrigeration apparatus 10E of FIG. 7, the branch point B1 of the lubricating oil line L3
Is provided with a three-way valve V1. The three-way valve V1 is connected to a signal transmission line C from a control unit (control unit) CU.
It is different from the embodiment of FIG. 6 in that it is configured to be controlled to open and close via L-1.

Under the control of the controller 44, the compression refrigeration system 10E shown in FIG. 7 is capable of switching between the cooling operation and the heating operation. It is possible to remove the water mixed in the oil. Specifically, in the compression refrigeration apparatus 10E in FIG. 7, the same control as that described in FIG. 5 is performed.

That is, during the heating operation, the same control as in steps S2 to S5 in FIG. 5 is performed, so that for a predetermined time (for example, one hour) immediately after the start of the operation, the total amount of the lubricating oil is reduced to the line L3-1. And the dryer 42 removes the mixed water. After the predetermined time elapses and the compression refrigeration apparatus 10C enters the steady operation state, the lubricating oil mostly flows through the bypass line L3-2 and bypasses the heat exchanger 40. A decrease in heating efficiency is prevented. This makes it possible to meet conflicting demands for removing moisture mixed in the lubricating oil and preventing a decrease in heating efficiency.

On the other hand, during the cooling operation, the three-way valve V1 is controlled so that most of the lubricating oil does not flow through the bypass line L3-2 but flows through the air heat exchanger 26 (step in FIG. 5). S6). Therefore, the lubricating oil is always cooled by the action of the air heat exchanger 26 and the cooling fan 32, and the moisture mixed in the dryer 42 is always removed.

The other configurations and operational effects of the sixth embodiment shown in FIG. 7 are the same as those of the sixth embodiment shown in FIGS.

FIG. 8 shows a seventh embodiment of the present invention. In each embodiment of FIGS. 1-7, the heat exchanger (air heat exchanger 26 or heat exchanger 40) that cools the lubricating oil is a lubricating oil line that connects the oil separator 14 and the junction B. It is interposed in L3 (L3-1, L3-2, L3-3). On the other hand, in the compression refrigeration system 10F according to the seventh embodiment of FIG. 8, a line connecting the compressor 12 and the oil separator 14 (a line through which a gas-phase refrigerant containing lubricating oil flows).
A third heat exchanger 46 is interposed in L1.

In the third heat exchanger 46, the amount of heat held by the gas-phase refrigerant mixed with the lubricating oil flowing in the line L1 is supplied to the water (other heat medium) flowing in the line L5. The gas-phase refrigerant mixed with the lubricating oil flowing in the line L1 is configured to be cooled. Here line L5
Communicates with the heat exchanger 46 and a thermal load (for example, hot water supply means) indicated by a symbol “G” in FIG. 8 to supply heat to the thermal load G.

A pressure sensor 48 and a temperature sensor 50 are provided near the outlet side (oil separator 14 side) of the heat exchanger 46 in the line L1 through which the gas-phase refrigerant containing the lubricating oil flows. The pressure and temperature of the gas-phase refrigerant flowing in the line L1 (containing lubricating oil) are detected. On the other hand, the line L5 is provided with an on-off valve V2 whose opening degree is adjustable as flow rate adjusting means. The opening of the on-off valve V2 is adjusted by the actuator 52.

The compression refrigeration system 10F further has a control means 60, and the control means 60 has the signal transmission lines CL-2 and CL-3 to flow through the line L1 (the lubricating oil flows). The pressure and temperature of the (mixed) gas-phase refrigerant are transmitted. The control means 60 transmits a control signal to the actuator 52 via the signal transmission line CL-4 in response to the pressure and the temperature, and controls the flow rate of the thermal medium flowing through the line L5.

As described above, if the liquid-phase refrigerant is sucked into the compressor 12, the compressor 12 may be damaged. Here, in the compression refrigeration apparatus 10F of FIG. 8, the refrigerant is double-cooled by the heat exchanger 46 and the condenser 16, so that only the heating by the evaporator 24 completely removes the refrigerant flowing through the line L2. There is a fear that cannot be vaporized.

The reason why the flow rate of the heat medium sent to the third heat exchanger 46 via the line L5 is controlled (the opening degree of the valve V2 is controlled) is that the liquid-phase refrigerant is sucked into the compressor 12. This is for preventing the above-mentioned situation. That is, the third
By measuring the pressure or temperature of the refrigerant cooled by the heat exchanger 46 by the sensors 48 and 50, the control means 60 determines how much the refrigerant is cooled by the heat exchanger 46 or the evaporator. At 24, it is possible to estimate / determine whether the refrigerant can completely evaporate. Then, when the control means 60 estimates or determines that the refrigerant does not completely evaporate in the evaporator 24 and the liquid refrigerant may be sucked into the compressor 12, the opening degree of the valve V2 is reduced. A control signal is generated to reduce the flow rate of the heat medium supplied to the heat exchanger 46 to suppress the degree of cooling or cooling of the refrigerant in the heat exchanger 46.

In the embodiment of FIG. 8, the moisture indicator 28 is interposed in the lubricating oil line L3. However, a dryer for removing moisture may be interposed. Further, a bypass line may be formed in the lubricating oil line L3.

The other configurations and operational effects of the seventh embodiment shown in FIG. 8 are the same as those of the first embodiment shown in FIGS.

It should be noted that the illustrated embodiment is merely an example, and is not a description of limiting the technical scope of the present invention.

[0078]

The effects of the present invention are listed below. (1) The moisture indicator can be prevented from being thermally damaged. (2) The moisture indicator can be installed in a highly sensitive measurement atmosphere to detect the water content in the lubricating oil with high accuracy. (3) The compressor can be prevented from being damaged due to the suction of the liquid-phase refrigerant. (4) When water absorption by the lubricating oil is dominant, mixed water can be removed. (5) By providing a line that bypasses the lubricating oil cooling heat exchanger provided in the lubricating oil line, the amount of heat held by the lubricating oil is not discarded outside the system, and the operating efficiency during heating operation is improved. You can do it. (6) In the case where the bypass line is provided, most of the refrigerant passes through the heat exchanger during the cooling operation, so that the operating efficiency during the cooling operation can be improved. (7) By providing a three-way switching valve at the location where the bypass line branches off from the lubricating oil line, it is possible to simultaneously improve operating efficiency during heating operation and remove moisture mixed with the lubricating oil. .

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating a second embodiment of the present invention.

FIG. 3 is a block diagram illustrating a third embodiment of the present invention.

FIG. 4 is a block diagram illustrating a fourth embodiment of the present invention.

FIG. 5 is a view showing a control flowchart of the embodiment of FIG. 4;

FIG. 6 is a block diagram illustrating a fifth embodiment of the present invention.

FIG. 7 is a block diagram illustrating a sixth embodiment of the present invention.

FIG. 8 is a block diagram illustrating a seventh embodiment of the present invention.

FIG. 9 is an explanatory view of a conventional compression refrigeration apparatus.

[Explanation of symbols]

1, 10, 10A, 10B, 10C, 10D, 10E,
10F: Compression refrigeration system 2, 12, Compressor 3, 14, ... Oil separator L1, L4 ... Line through which gas-phase refrigerant mixed with lubricating oil flows L2 ... Refrigerant line L3, L3-1, L3-2, L3-3 ... Lubricating oil line L5 ... Heat medium line B, B2 ... Confluence point B1 ... Branch point 4, 16 ... Condenser 5, 18 Liquid receivers 6, 20, 42 Dryer 7, 28 Moisture indicator 8, 22 Expansion valve 9, 24 Evaporator 26, 40, 46 Heat exchanger 30 ... decompression device 4F, 9F, 32, 34 ... fan 44, 60 ... control means 48 ... pressure sensor 50 ... temperature sensor V1 ... three-way switching valve V2 ... opening and closing valve 52 ... Actuators

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F25B 43/00 F25B 43/00 T

Claims (7)

[Claims] 1. A lubricating oil line, through which lubricating oil separated by an oil separator flows, is provided with a heat exchanger for lowering the temperature of the lubricating oil and a moisture indicator for detecting the content of water mixed in the lubricating oil. A compression refrigeration apparatus, wherein the heat exchanger is disposed in a region closer to the oil separator than the moisture indicator. 2. The compression refrigeration system according to claim 1, wherein said heat exchanger is an air heat exchanger (26) for dissipating the amount of heat held by the lubricating oil into the atmosphere. 3. The compression refrigerating apparatus according to claim 1, wherein the heat exchanger is configured to exchange heat between the refrigerant passing through an evaporator interposed in the refrigerant line and the lubricating oil. 4. The lubricating oil line bypasses a heat exchanger, a moisture indicator, a first line provided with a dryer for removing moisture mixed in the lubricating oil, and a heat exchanger, a moisture indicator, and a dryer. The compression refrigeration apparatus according to any one of claims 1 to 3, which branches into a bypass line. 5. A three-way switching valve is provided at a location where the first line and the bypass line branch off, and the three-way switching valve is used for cooling operation or heating operation and for a predetermined time from the start of operation. Before the time elapses, the bypass line is closed and the opening and closing control is performed so that the lubricating oil flows to the line side where the heat exchanger and the dryer are interposed. 5. The compression refrigeration system according to claim 4, wherein the compression refrigeration apparatus is configured to be controlled to open and close so that the lubricating oil flows through the bypass line. 6. A lubricating oil line, through which the lubricating oil separated by the oil separator flows, is provided with a moisture indicator, which is configured to detect the content of moisture mixed in the lubricating oil. A heat exchanger is interposed in a line connecting the compressor for compressing the refrigerant mixed with the lubricating oil and the oil separator, and the heat exchanger is discharged from the compressor and mixed with the lubricating oil. A compression refrigeration apparatus characterized in that the refrigerant and a heat medium flowing through a line communicating with a thermal load exchange heat. 7. The method for operating a compression refrigeration apparatus according to claim 5, wherein a step of determining whether the operation is a cooling operation or a heating operation, and the required time has elapsed from the start of the operation in the case of the heating operation. In the step of measuring whether or not the cooling operation or the heating operation and before the lapse of a predetermined time from the start of operation, the bypass line is closed and the line side where the heat exchanger and the dryer are interposed is used. Compression, characterized in that it comprises a step of controlling opening and closing so that lubricating oil flows, and a step of controlling opening and closing such that lubricating oil flows through a bypass line at a stage after a predetermined time has elapsed from the start of the heating operation. Method of operating the refrigeration system.