JP6758963B2 - Freezer - Google Patents

Description

The present invention relates to a freezer equipped with an oil separator.

The refrigerating machine oil used in the compressor that compresses the refrigerant is mixed in the compressed refrigerant gas discharged from the compressor and circulates in the refrigerating circuit. When this refrigerating machine oil enters a heat exchanger such as a condenser or an evaporator, heat conduction is hindered. Therefore, as disclosed in Patent Document 1 and the like, the compressed refrigerant discharged from the compressor is an oil separator ( The refrigerating machine oil is separated by passing through an oil separator). The separated refrigerating machine oil is decompressed by a decompressing part such as a capillary tube and returned to the suction side of the compressor.

The larger the capacity of the oil separator, the higher the oil separation performance. However, in the refrigerating equipment installed in vehicles such as refrigerator cars, it is not possible to install an oil separator of sufficient size due to the space inside the vehicle. For example, small oil separators are dispersed and arranged in two places, and these oil separators are connected in series to ensure the required oil separation performance. The oil return line extending from the bottom of the two oil separators is connected to the suction side of the compressor via a capillary tube, respectively. By using the capillary tube, it is possible to omit members such as a solenoid valve and simplify the configuration of the oil return pipeline.

JP-A-2007-147212

As described above, if the oil return pipeline from the oil separator is connected only to the suction side of the compressor via the capillary tube without providing a solenoid valve, etc., the amount of oil returned from the oil separator will be large when the refrigeration system is stopped. The portion may pass through the capillary tube and accumulate inside the compressor, and when the compressor is started, the return oil may be liquid-compressed and the compressor may be damaged.
In order to prevent this, conventionally, a height difference is provided between the compressor and the accumulator so that the return oil from the oil separator collects toward the accumulator on the upstream side of the compressor when the refrigerating device is stopped. However, this imposes restrictions on the placement position of the accumulator.

On the other hand, in a refrigerating device for a vehicle such as an automobile, it is necessary to reduce the size of the compressor due to the installation space, and an oil pump or an oil storage unit is not provided inside the compressor. Therefore, the lubrication of the internal mechanism of the compressor is mist lubrication due to the mist of refrigerating machine oil contained in the refrigerant.
However, when the compressor is an open type driven by an external power such as an engine, the bearing member and shaft seal member provided at the portion where the main shaft protrudes outward from the compressor housing are sufficient with mist lubrication alone. There was a risk that it would not be lubricated.

The present invention has been made to solve such a problem, and improves the lubrication condition of the compressor by utilizing the return oil from the oil separator and prevents liquid compression at the time of starting the compressor. It is an object of the present invention to provide a refrigerating apparatus capable of performing.

The refrigerating apparatus according to the present invention is connected in series to a compressor that compresses the refrigerant and a refrigerant circuit that extends from the discharge side of the compressor, and contains refrigerating machine oil contained in the refrigerant discharged from the compressor. A plurality of oil separators for separating and collecting and a plurality of oil return pipelines extending from the plurality of oil separators are provided, and one of the plurality of oil return pipelines is located on the suction side of the compressor. Connected, another one of the plurality of oil return conduits is connected to the internal mechanism of the compressor.

According to the refrigerating apparatus having the above configuration, the refrigerating machine oil is separated and recovered from the discharged refrigerant by a plurality of oil separators, and the recovered refrigerating machine oil passes through a plurality of oil return pipelines extending from each oil separator. It is returned to the suction side of the compressor and the internal mechanism of the compressor. Therefore, the return oil forcibly lubricates the internal mechanism of the compressor. That is, the return oil can be effectively used to improve the lubrication conditions of the compressor as compared with the conventional lubrication using only mist lubrication.

Further, since the return destination of the refrigerating machine oil is dispersed between the suction side of the compressor and the internal mechanism portion as described above, the entire amount of the return oil does not concentrate on the suction side of the compressor when the refrigerating apparatus is stopped. Therefore, it is possible to prevent liquid compression when the compressor is started. Further, it is less necessary to provide a height difference between the compressor and the accumulator so that the return oil returns to the accumulator as in the conventional case, and the degree of freedom in the arrangement position of the accumulator is increased.

In the refrigerating apparatus having the above configuration, the compressor is an open type compressor in which the internal mechanism portion is lubricated by the mist of the refrigerating machine oil, and the oil return pipeline connected to the internal mechanism portion is inside the inside. It may be connected to at least one of the bearing member and the shaft seal member in the bearing portion of the mechanical portion.

In an open type compressor, there is a risk that the bearing member and shaft seal member provided in the bearing portion may not be sufficiently lubricated only by mist lubrication, but the bearing member and shaft seal member in this bearing portion are connected from the oil return pipeline. Since the return oil is supplied, it is possible to forcibly lubricate the bearing portion, which is difficult to lubricate by mist lubrication, and improve the lubrication conditions.

In the freezing device having the above configuration, it is preferable that the oil return pipeline connected to the internal mechanism portion extends from the most upstream side of the plurality of oil separators.

More refrigerating machine oil is recovered in the upstream oil separator than in the downstream oil separator. For this reason, by connecting the oil return pipe extending from the oil separator on the upstream side to the internal mechanism of the compressor, the amount of oil supplied to the internal mechanism can be increased and the lubrication conditions can be reliably improved. it can.
In addition, since the oil return line extending from the oil separator on the downstream side where the amount of refrigerating machine oil recovered is small is connected to the suction side of the compressor, the refrigerating machine oil that returns to the suction side of the compressor when the refrigerating device is stopped The amount can be reduced to prevent liquid compression when the compressor is started.

In the freezing device having the above configuration, an on-off valve may be provided in the oil return pipeline connected to the internal mechanism portion. By doing so, the amount of return oil supplied to the internal mechanism of the compressor can be controlled as needed by opening and closing the on-off valve.
For example, during medium to high load operation of the refrigerating apparatus, the amount of refrigerant passing through the compressor increases, so that mist lubrication due to the mist of refrigerating machine oil contained in the refrigerant becomes good. For this reason, the on-off valve is closed or the opening is reduced to stop the supply of return oil to the internal mechanism or reduce the supply amount to prevent excessive supply of refrigerating machine oil into the system of the refrigerating apparatus. can do.

In addition, during low-load operation of the refrigeration system or during refrigeration operation in which the evaporator temperature and refrigerant pressure (that is, the density of the intake refrigerant) are further lowered, the amount of refrigerant passing through the compressor is reduced, and the refrigerating machine oil contained in the refrigerant is reduced. There is a possibility that the lubrication of the internal mechanism of the compressor will be insufficient only by the mist lubrication by the mist. In such a case, the on-off valve is opened and the oil is supplied back to the internal mechanism to forcibly lubricate the internal mechanism, and the lubrication condition can be improved.
Further, by closing the on-off valve when the refrigerating apparatus is stopped, it is possible to prevent the refrigerating machine oil collected in the oil separator from flowing down the oil return pipe due to the high and low differential pressure and accumulating in the compressor. As a result, it is possible to avoid liquid compression when the compressor is started.

As described above, according to the refrigerating apparatus according to the present invention, it is possible to improve the lubrication condition of the compressor by utilizing the return oil from the oil separator and prevent liquid compression at the time of starting the compressor. ..

It is a schematic block diagram of the freezing apparatus which shows 1st Embodiment of this invention. It is a vertical sectional view of the compressor which enlarged the part II of FIG. It is a schematic block diagram of the freezing apparatus which shows the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a schematic configuration diagram of a freezing device showing the first embodiment of the present invention. The refrigerating device 1 is, for example, a circuit dedicated to cooling used for cooling a refrigerating room in a refrigerated transport vehicle, but can also be applied to an air conditioner for an automobile or the like.

The refrigerating device 1 includes an open type compressor 2 (a type in which the main shaft protrudes to the outside) that is driven by a vehicle engine or the like to compress the refrigerant. The compressor 2 is, for example, a scroll type compressor, and includes a pulley 3 with a clutch that is rotationally driven by a belt or the like, a suction port 4, and a discharge port 5. The freezing device 1 includes a closed-loop refrigerant circuit 7 that extends from the discharge port 5 of the compressor 2 and returns to the suction port 4, and the oil separator 8 and the oil are separated in this order from the upstream side (compressor 2 side). A vessel 9, a condenser 10, a receiver 11, an expansion valve 12, an evaporator 13, and an accumulator 14 are connected. That is, the two oil separators 8 and 9 are connected in series to the refrigerant circuit 7 extending from the discharge side of the compressor 2. These oil separators 8 and 9 are divided into two in relation to the vehicle mounting space. The condenser 10 is provided with a cooling fan 10a, and the evaporator 13 is provided with a blower fan 13a.

An oil return pipe 16 extends from the bottom of the oil separator 8 on the upstream side, and the tip thereof is connected to an internal mechanism portion (for example, a bearing portion 26) of the compressor 2. Further, an oil return pipe 17 extends from the bottom of the oil separator 9 on the downstream side and is connected to the suction side of the compressor 2, for example, a section between the suction port 4 and the accumulator 14 in the refrigerant circuit 7. ..
The capillary tube 19 and the solenoid valve 20 (on-off valve) are connected to the oil return pipe 16, and the capillary tube 21 is connected to the oil return pipe 17. The members 7 to 21 described above are all known. Although the solenoid valve 20 is not essential, by providing the solenoid valve 20, the amount of return oil supplied from the oil return pipe 16 to the compressor 2 can be controlled as described later.

FIG. 2 is a vertical cross-sectional view of the compressor 2 in which the part II of FIG. 1 is enlarged. The compressor 2 includes a housing 25 made of a light alloy, and a spindle 27 is pivotally supported by a bearing portion 26 provided inside the housing 25. The main shaft 27 penetrates from the inside to the outside of the housing 25, and the above-mentioned pulley 3 with a clutch is attached to the outer end portion thereof. The bearing portion 26 has a configuration including an inner main bearing 26a (bearing member), an outer sub-bearing 26b (bearing member), and an outer lip seal 26c (shaft seal member).

When the pulley 3 with a clutch is rotationally driven by an external force such as an engine and the electromagnetic clutch 3a inside the clutch is turned on, the rotation of the pulley 3 with a clutch is transmitted to the spindle 27, and an eccentric shape is formed at the inner end of the spindle 27. The crank pin 27a swivels and revolves the swivel scroll 31 of the compression mechanism 30 with respect to a fixed scroll (not shown) via the drive bush 28 and the drive bearing 29. As a result, the refrigerant sucked from the suction port 4 is compressed and discharged from the discharge port 5 shown in FIG.

Refrigerant oil is contained in the refrigerant in a predetermined ratio, and internal mechanical parts such as the bearing portion 26 and the compression mechanism 30 are lubricated by the mist of the refrigerating machine oil contained in the refrigerant. Then, as described above, the other end of the oil return pipe 16 extending from the bottom of the oil separator 8 on the upstream side shown in FIG. 1 is connected to the oil supply passage 35 formed inside the housing 25 and the bearing portion. It is connected to 26. The oil supply passage 35 communicates with the annular space S between the sub bearing 26b and the lip seal 26c in the bearing portion 26. It should be noted that the oil return pipeline 16 may be communicated not only with the bearing portion 26 but also with other internal mechanism portions as needed.

The freezing device 1 is configured as described above.
The high-temperature and high-pressure refrigerant compressed by the compressor 2 is discharged from the discharge port 5, flows through the refrigerant circuit 7, and is contained when sequentially passing through the oil separator 8 on the upstream side and the oil separator 9 on the downstream side. Most of the refrigerating machine oil that has been separated is separated. The compressed refrigerant separated from the refrigerating machine oil flows to the condenser 10, where it is heat-exchanged with the outside air by the cooling fan 10a and cooled to be condensed, and most of it becomes liquid phase. At that time, since the refrigerating machine oil in the refrigerant is separated in the oil separators 8 and 9 in advance, heat conduction is not hindered.

Next, the condensed refrigerant is gas-liquid separated by the receiver 11, and only the liquid-phase condensed refrigerant expands in the expansion valve 12, is set to an appropriate pressure, and flows to the evaporator 13. The condensed refrigerant takes heat from the evaporator 13 by vaporizing it in the evaporator 13, and at the same time, the air in the refrigerating chamber is cooled by the evaporator 13 and blown out into the refrigerating chamber by operating the blower fan 13a to cool the refrigerating chamber. It is offered to. The refrigerant vaporized by the evaporator 13 separates the unevaporated liquid-phase refrigerant in the accumulator 14, and only the vapor-phase refrigerant is sucked into the suction port 4 of the compressor 2 again.

The refrigerating machine oil separated from the compressed refrigerant in the oil separator 9 on the downstream side passes through the capillary tube 21 to reduce the pressure, and is connected to the suction side of the compressor 2, that is, the suction port 4 via the oil return pipe 17. It is returned to the downstream section. The refrigerating machine oil returned to the refrigerant circuit 7 is mixed with the refrigerant and sucked into the compressor 2, and mist lubricates the internal mechanisms such as the bearing portion 26 and the compression mechanism 30 inside the compressor 2.

On the other hand, if the solenoid valve 20 is open, the refrigerating machine oil separated from the compressed refrigerant in the oil separator 8 on the upstream side passes through the bearing tube 19 to reduce the pressure, and the oil return pipe 16 and the compressor 2 It is directly supplied to the bearing portion 26 via the oil supply passage 35 (see FIG. 2). Specifically, as shown in FIG. 2, the refrigerating machine oil that has flowed into the annular space S defined in the bearing portion 26 flows to the sub-bearing 26b and the lip seal 26c to lubricate them. The refrigerating machine oil that lubricates the sub bearing 26b is further lubricated with the main bearing 26a, mixed with the refrigerant, and discharged from the discharge port 5 to the refrigerant circuit 7.

With conventional lubrication using only mist lubrication, there is a risk that the sub-bearing 26b and lip seal 26c of the bearing portion 26 in the open type compressor 2 will not be sufficiently lubricated, but according to this practical form, the bearing portion 26 is oiled. Since the return oil is directly supplied from the return pipeline 16, it is possible to effectively utilize the return oil to forcibly lubricate the bearing portion 26, which is difficult to lubricate by mist lubrication, and improve the lubrication condition of the bearing portion 26. it can.

Moreover, according to the present embodiment, the return destination of the refrigerating machine oil recovered by the oil separators 8 and 9 is dispersed between the suction side of the compressor 2 and the bearing portion 26, so that the returning oil is returned when the refrigerating device 1 is stopped. The total amount of the above is not concentrated on the suction side of the compressor 2. Therefore, it is possible to prevent liquid compression when the compressor 2 is started. Further, it is less necessary to provide a height difference between the compressor 2 and the accumulator 14 so that the return oil returns to the accumulator 14 as in the conventional case, and the degree of freedom in the arrangement position of the accumulator 14 is increased.

The oil return pipeline 16 connected to the bearing portion 26 extends from the oil separator 8 on the upstream side, but the oil separator 8 on the upstream side has more refrigerating machine oil than the oil separator 9 on the downstream side. By connecting the oil return pipeline 16 extending from the oil separator 8 on the upstream side to the bearing portion 26 of the compressor 2, the amount of oil supplied to the bearing portion 26 is increased and the lubrication conditions are adjusted. It can be definitely improved.
Further, since the oil return pipe 17 extending from the oil separator 9 on the downstream side where the recovery amount of the refrigerating machine oil is small is connected to the suction side of the compressor 2, the suction of the compressor 2 is performed when the refrigerating device 1 is stopped. The amount of refrigerating machine oil returning to the side can be reduced, and liquid compression at the time of starting the compressor 2 can be effectively prevented.

As described above, the oil separator 8 on the upstream side recovers a large amount of refrigerating machine oil, but the compressor 2 has a solenoid valve 20 provided in the oil return pipe 16 extending from the oil separator 8. The amount of return oil supplied to the bearing portion 26 can be controlled as needed.
For example, during medium to high load operation of the refrigerating apparatus 1, since the amount of the refrigerant passing through the compressor 2 is large, mist lubrication due to the mist of the refrigerating machine oil contained in the refrigerant becomes good. Therefore, the solenoid valve 20 is closed or the opening degree is reduced to stop the supply of the return oil to the bearing portion 26 or the supply amount is reduced, so that the refrigerating machine oil is excessively supplied into the system of the refrigerating apparatus 1. Can be suppressed.

Further, during a low load operation of the refrigerating device 1 or a refrigerating operation in which the temperature and the refrigerant pressure of the evaporator 13 are further lowered, the density of the intake refrigerant is lowered, and the refrigerant circulation amount of the entire system is lowered to be compressed. The amount of refrigerant passing through the machine 2 is reduced, and there is a possibility that the lubrication of the bearing portion 26 will be insufficient only by mist lubrication by the mist of the refrigerating machine oil contained in the refrigerant. In such a case, the solenoid valve 20 can be opened and the bearing portion 26 can be forcibly lubricated by supplying oil back to the bearing portion 26 to improve the lubrication condition of the bearing portion 26.

Further, when the refrigerating apparatus 1 is stopped, the solenoid valve 20 is closed so that the refrigerating machine oil collected in the oil separator 8 flows down the oil return pipe 16 due to the high and low differential pressure and is accumulated in the compressor 2. Can be prevented. As a result, liquid compression at the time of starting the compressor 2 can be avoided. If necessary, it is conceivable to provide a solenoid valve 20 in the oil return pipe 17 extending from the oil separator 9 on the downstream side. As a result, it is possible to prevent the return oil from the oil separator 9 from flowing down excessively to the suction side of the compressor 2 when the refrigerating device 1 is stopped.

As described above, according to the refrigerating apparatus 1 according to the present embodiment, the lubrication conditions of the compressor 2 are improved by effectively utilizing the return oil from the oil separators 8 and 9, and when the compressor 2 is started. It is possible to prevent liquid compression in.

[Second Embodiment]
FIG. 3 is a schematic configuration diagram of a freezing device showing a second embodiment of the present invention.
In this refrigerating device 51, contrary to the refrigerating device 1 shown in FIG. 1, an oil return pipe 16 extending from the oil separator 8 on the upstream side is connected to the suction side of the compressor 2, and oil separation on the downstream side is performed. The oil return pipe 17 extending from the vessel 9 is connected to the bearing portion 26 of the compressor 2. It is preferable to provide a solenoid valve 20 in the oil return pipe 16 having a large amount of return oil. If necessary, the solenoid valve 20 may also be provided in the oil return line 17. Other configurations are the same as those of the freezing device 1 of the first embodiment.

According to the refrigerating device 51, the return destination of the refrigerating machine oil recovered by the oil separators 8 and 9 is distributed to the suction side of the compressor 2 and the bearing portion 26 as in the refrigerating device 1 of the first embodiment. Therefore, it is possible to prevent the entire amount of the return oil from concentrating on the suction side of the compressor 2 when the refrigerating device 51 is stopped, and to prevent liquid compression when the compressor 2 is started.

Further, since the return oil from the oil separator 9 on the downstream side, which recovers a small amount of refrigerating machine oil, returns to the bearing portion 26 of the compressor 2, the solenoid valve 20 is not provided in the oil return pipe line 17. Even if the pressure is reduced only by the bearing tube 21, the amount of return oil flowing down to the compressor 2 when the refrigerating device 51 is stopped does not become excessive, and this also prevents liquid compression when the compressor 2 is started. can do.

The present invention is not limited to the configurations of the first and second embodiments described above, and changes and improvements can be made as appropriate, and the embodiments with such changes and improvements are also the present invention. It shall be included in the scope of rights.
For example, in the above embodiment, the compressor 2 has been described as being an open type, but a closed type compressor (compressor integrated with an electric motor, etc.) may be used.
When the solenoid valves 20 are provided in the oil return pipes 16 and 17, it is conceivable that the capillary tubes 19 and 21 are omitted by providing the solenoid valves 20 with a flow rate adjusting function.
Further, the type, shape, position, and the like of each component device connected to the refrigerant circuit 7 do not necessarily have to be those of the above embodiment.

1,51 Refrigerant device 2 Compressor 7 Refrigerant circuit 8, 9 Oil separator 16, 17 Oil return line 19, 21 Capillary tube 20 Solenoid valve (open / close valve)
26 Bearing (compressor internal mechanism)
26a Main bearing (bearing member)
26b Sub bearing (bearing member)
26c Lip seal (shaft seal member)

Claims (3)

A compressor that compresses the refrigerant and
A plurality of oil separators connected in series to a refrigerant circuit extending from the discharge side of the compressor to separate and recover refrigerating machine oil contained in the refrigerant discharged from the compressor.
A plurality of oil return pipelines extending from the plurality of oil separators are provided.
One of the plurality of oil return pipes is connected to the suction side of the compressor.
Another one of the plurality of oil return pipes is connected to the internal mechanism of the compressor .
Wherein the oil return line connected to the internal mechanism, out of the plurality of oil separators, refrigeration that not extend from the most upstream one device. The compressor is an open compressor in which the internal mechanism is lubricated by the mist of the refrigerating machine oil.
The refrigerating apparatus according to claim 1, wherein the oil return pipeline connected to the internal mechanism portion is connected to at least one of a bearing member or a shaft seal member in the bearing portion of the internal mechanism portion. The refrigerating apparatus according to claim 1, wherein an on-off valve is provided in the oil return pipeline connected to the internal mechanism portion.

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