JP2009216292A - Transport refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a transport refrigerating device capable of suppressing excessive rise of a temperature of a discharged refrigerant by efficiently cooling the oil separated by an oil separator without using an additional component, improving durability and reliability of products, and exerting desired refrigerating performance. <P>SOLUTION: In this transport refrigerating device 3 wherein a condenser 9 is disposed through partition walls 21A, 21B, 21C at a front part of a heat insulating housing 20, a condenser fan 15 is disposed at its rear part, and the outside air sucked from a front face of the condenser 9 by the condenser fan 15 is circulated to the condenser 9, and then discharged in the vertical direction through an outside air circulating pathway 22, a discharge pipe 12A from the compressor 4 is disposed on the outside air circulating pathway 22 for circulating the outside air through the condenser 9, and at least one of the oil separator 8 for separating the oil in a refrigerant gas and an oil return pipe 14 for returning the oil separated by the oil separator 8 to the suction pipe 12B side of the compressor 4 is further disposed. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a transport refrigeration apparatus which is attached to a freezer of a refrigerated vehicle and cools the inside thereof.

  An integrated transport refrigeration apparatus mounted on a refrigeration vehicle includes a heat insulating housing attached to a front wall of a freezer, an evaporator provided on an inner side of the heat insulating housing, an evaporator fan, and the like, and heat insulation. A condenser unit having a condenser and a condenser fan disposed on the front surface of the outer side of the housing, sucking the air in the freezer through the evaporator fan from the suction inlet, circulating it through the evaporator, cooling it, and then blowing it out It is configured to blow out from the mouth into the freezer.

  This transport refrigeration apparatus is usually mounted on the upper part of the front wall of the freezer, but is subject to the following restrictions from the viewpoint of the mounting. On the evaporator unit side, it is necessary to ensure a certain amount of dimension in the unit height direction in order to ensure a ventilation path between the inside of the freezer. However, it is necessary to prevent interference when the cabin of the vehicle is tilted forward, and the lower part of the unit needs to have a cross-sectional shape cut obliquely toward the front upper side. (See FIG. 1). In addition, it is desirable to make the protruding dimension from the front wall of the freezer in the unit forward as small as possible.

For this reason, the capacitor unit is provided with partition walls on both the left and right sides of the heat insulating housing to partition the external airflow passage, and a capacitor is disposed in front of the heat insulating housing at a predetermined interval, and a capacitor fan is disposed behind the capacitor fan. Although it is set as the arrangement | positioning structure, the space | interval between a heat insulation housing and a capacitor | condenser is made into the minimum required. Accordingly, the accessories such as the oil separator, the refrigerant pipe, and the control parts are provided with a space on both the left and right sides of the partition wall.
On the other hand, on the refrigeration cycle side, if a large amount of lubricating oil sealed in the compressor circulates in the cycle, the heat exchange performance of the evaporator and condenser will be hindered, so an oil separator is placed in the discharge pipe from the compressor. Is provided to separate the oil contained in the refrigerant gas and return the oil to the suction pipe side of the compressor.

The installation of the oil separator is effective in eliminating the factors that hinder the heat exchange performance, but if the separated high-temperature oil is returned directly to the intake piping side of the compressor, the temperature of the intake refrigerant gas will increase. As a result, the discharged refrigerant temperature becomes a cause of excessive increase, and the suction efficiency (compression efficiency) is lowered. In order to solve this problem, Patent Document 1 provides an air-cooled oil cooler in the oil return pipe from the oil separator, and this oil cooler is provided downstream of the cooling air passage of the condenser (condenser). A technique is disclosed in which it is arranged to cool the oil back to the compressor.
JP-A-8-94194

  However, in a transport refrigeration system mounted on a refrigeration vehicle, it is not easy to secure a space for installing an oil cooler on the capacitor unit side, which is limited in size, and additional installation of an oil cooler is not possible. This is not a good measure because it increases costs. In such a situation, in a transport refrigeration apparatus having a high pressure ratio and a discharge refrigerant temperature that is likely to excessively increase, while ensuring the durability and reliability of the product by suppressing an excessive increase in the discharge refrigerant temperature, In order to exhibit the refrigeration performance, how to reduce the temperature of the oil separated by the oil separator is an issue.

  The present invention has been made in view of such circumstances, and the oil separated by the oil separator is efficiently cooled without additional components to suppress an excessive increase in the discharge refrigerant temperature, and the product An object of the present invention is to provide a transport refrigeration apparatus capable of improving the reliability and reliability and at the same time exhibiting the intended refrigeration performance.

In order to solve the above problems, the transport refrigeration apparatus of the present invention employs the following means.
That is, the transport refrigeration apparatus according to the present invention is disposed on a heat insulating housing that can be attached to the outer wall of the freezer, an evaporator unit disposed on the inner side of the heat insulating housing, and an outer front surface of the heat insulating housing. The capacitor unit, the capacitor unit being installed via a partition wall provided on the left and right sides of the heat insulating housing at a predetermined interval in front of the heat insulating housing, and at the rear of the capacitor fan The refrigeration apparatus for transport is configured such that the outside air sucked from the front surface of the condenser by the condenser fan is exhausted in the vertical direction after passing through the condenser and then through the external airflow passage formed at the interval. In the external airflow passage through which the external air is circulated through the condenser, At least one of an oil separator that is provided in the discharge pipe and separates oil in the refrigerant gas, or an oil return pipe that returns the oil separated by the oil separator to the suction pipe side of the compressor is disposed. It is characterized by that.

  According to the present invention, since at least one of the oil separator or the oil return pipe is disposed on the external airflow passage formed at the interval between the capacitor on the capacitor unit side and the heat insulating housing, the oil separator While the oil separated in step 1 is returned from the oil separator to the suction pipe side of the compressor through the oil return pipe, the oil separator or the oil return pipe disposed on the external airflow passage is used to pass through the condenser. The temperature of the oil returned to the suction piping side of the compressor can be reduced by heat exchange with the circulated outside air and cooling. Accordingly, it is possible to suppress an excessive increase in the discharged refrigerant temperature and deterioration due to the high temperature of the oil, and to improve the durability and reliability of the product. Further, the degree of superheat of the refrigerant sucked into the compressor can be suppressed, and the compression efficiency can be improved. Furthermore, since the oil temperature can be reduced without adding an oil cooler or the like, the expected refrigeration performance can be exhibited without increasing costs or adding additional parts.

  Furthermore, the transport refrigeration apparatus of the present invention is characterized in that, in the transport refrigeration apparatus, both the oil separator and the oil return pipe are disposed on the external airflow passage.

  According to the present invention, since both the oil separator and the oil return pipe are disposed on the external airflow passage, the oil returned to the suction pipe side of the compressor is cooled by both the oil separator and the oil return pipe. In addition, the temperature can be further reduced. Therefore, various effects by reducing the oil temperature returned to the compressor can be further enhanced.

  Furthermore, the transport refrigeration apparatus of the present invention is the above transport refrigeration apparatus, wherein the oil return pipe includes any one of a capillary tube, a fixed throttle, and an expansion valve. One of the expansion valves is disposed on the external airflow passage.

  According to the present invention, since the oil return pipe includes any one of the capillary tube, the fixed throttle, and the expansion valve, the pressure and flow rate of the oil returned to the suction pipe side of the compressor can be appropriately adjusted. Can do. Therefore, it is possible to reduce the oil temperature returned to the compressor while maintaining a pressure difference, ensuring a certain oil level in the oil separator, and preventing the occurrence of compression loss due to refrigerant gas being bypassed. it can.

  Furthermore, the transport refrigeration apparatus of the present invention is the above-described transport refrigeration apparatus, wherein the oil separator and / or the oil return pipe is the condenser on the external airflow passage partitioned by the partition wall. It is arranged at a corner away from the rotation area of the fan.

  According to the present invention, since the oil separator and / or the oil return pipe are disposed at a corner away from the rotation area of the condenser fan on the external airflow passage partitioned by the partition wall, Not to be an obstacle, of course, it will not interfere with the installation or removal of the condenser fan. Therefore, even if the oil separator and / or the oil return pipe are disposed on the external airflow passage, there is no problem in the maintenance of the condenser fan or the like.

  Furthermore, in the transport refrigeration apparatus of the present invention, in any one of the transport refrigeration apparatuses described above, the partition wall has a wide space between the left and right partition walls from the front end side toward the heat insulating housing side. The oil separator and / or the oil return pipe are arranged at an angle between the partition wall and the heat insulating housing.

  According to the present invention, the left and right partition walls are provided obliquely so that the distance increases from the front end side toward the heat insulation housing, and the oil separator and the corner formed by the partition wall and the heat insulation housing are provided. Since the oil return pipe is provided, the oil separator and the air flow path are formed on the outer airflow path by utilizing a single space formed by the partition wall and the heat insulation housing, which is generated when the partition wall is provided obliquely for the purpose of increasing the strength. An oil return line can be provided. Therefore, it is possible to relatively easily secure an installation space for the oil separator and / or the oil return pipe in a narrow space.

  Furthermore, the transport refrigeration apparatus of the present invention is characterized in that, in any of the transport refrigeration apparatuses described above, the oil separator has a vertically long cylindrical shape.

  According to the present invention, since the oil separator has a vertically long cylindrical shape, the vertically long oil separator can be accommodated along a vertical direction in a corner on the external airflow passage partitioned by the partition wall. . Therefore, the oil separator can be installed relatively easily in a narrow space.

  According to the present invention, while the oil separated by the oil separator is returned from the oil separator to the suction pipe side of the compressor through the oil return pipe, the oil separator or the oil return disposed on the outer airflow passage. One of the pipes can be cooled by exchanging heat with the outside air circulated through the condenser, and the temperature of the oil returned to the suction pipe side of the compressor can be reduced. It is possible to suppress the deterioration due to, and improve the durability and reliability of the product. Further, the degree of superheat of the refrigerant sucked into the compressor can be suppressed, and the compression efficiency can be improved. Furthermore, since the oil temperature can be reduced without adding an oil cooler or the like, the expected refrigeration performance can be exhibited without increasing costs or adding additional parts.

Embodiments according to the present invention will be described below with reference to the drawings.
[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows a side view of a front portion of a refrigeration vehicle 1 equipped with a transport refrigeration apparatus 3 according to this embodiment, and FIG. 2 shows a front view of the transport refrigeration apparatus 3. .
The refrigerated vehicle 1 includes a cabin 1A and a traveling engine 1B, and the freezer 2 is mounted on the rear chassis of the cabin 1A. The freezer 2 is constituted by a box body having a heat insulating structure, and includes a luggage loading / unloading door (not shown) on a rear surface or a side surface.

  The transport refrigeration apparatus 3 has a configuration in which a condenser unit 5 and an evaporator unit 6 are integrated as will be described later, and is fixed at a position above the front wall 2A of the freezer 2 so as to partially protrude above the cabin 1A. is set up. The evaporator unit 6 communicates with the inside of the freezer 2 so that the inside air can be circulated to the evaporator unit 6. Further, the compressor 4 which is the configuration of the transport refrigeration apparatus 3 is installed on the side wall of the traveling engine 1B in the engine room on the cabin 1A side, and can be driven by the traveling engine 1B via the belt and the clutch 4A. Has been.

  FIG. 6 shows a refrigeration cycle 7 of the transport refrigeration apparatus 3. The refrigeration cycle 7 includes the compressor 4 that compresses the refrigerant gas, an oil separator 8 that is provided in the discharge pipe 12A from the compressor 4 and separates lubricating oil (oil) from the high-temperature and high-pressure refrigerant gas, A condenser 9 that condenses and liquefies the refrigerant by exchanging heat between the separated refrigerant and the outside air, and an expansion valve 10 that adiabatically expands the high-pressure liquid refrigerant condensed by the condenser 9 to form a low-temperature and low-pressure gas-liquid two-phase refrigerant; And an evaporator 11 for exchanging heat between the adiabatic expanded refrigerant and the air in the freezer 2, and these are sequentially connected by a refrigerant pipe 12.

  Further, the oil separated from the refrigerant gas by the oil separator 8 is configured to be returned to the suction pipe 12B side of the compressor 4 through an oil return pipe 14 provided with a capillary tube 13 for flow rate adjustment. Yes. Furthermore, the condenser 9 and the evaporator 11 are respectively provided with a condenser fan 15 that circulates outside air to the condenser 9 and an evaporator fan 16 that circulates the air in the freezer 2 to the evaporator 11.

  As shown in FIGS. 3 and 4, the transport refrigeration apparatus 3 is open at the freezer 2 side and has a substantially U-shaped cross section with the lower surface being an inclined surface. A heat insulating housing 20 having a lower surface is provided. The heat insulating housing 20 is fitted into a horizontally long rectangular opening (not shown) provided on the front wall 2A of the freezer 2 and fixedly installed in the freezer 2 with bolts or the like.

  An evaporator unit comprising an evaporator 11 constituting the refrigeration cycle 7, an evaporator fan 16 that circulates the air in the freezer 2 through the evaporator 11, and the like in an internal space opened in the freezer 2 of the heat insulating housing 20. 6 is disposed. The evaporator unit 6 is provided with a partition plate (not shown) facing the inside of the freezer 2, and the air in the freezer 2 is evaporated through an air suction port and an air outlet provided in the partition plate. 11 (see the arrow in FIG. 4). Further, a drain pan, a drain pan heater, etc. (not shown) are disposed below the evaporator 11.

  On the other hand, partition walls 21A, 21B, and 21C are erected on the front surface on the outer side of the heat insulating housing 20 at both the left and right sides and at an intermediate position, and capacitors are provided via the partition walls 21A, 21B, and 21C. A unit 5 is provided. The capacitor unit 5 includes a pair of left and right capacitors 9 arranged in a vertical direction at a front end of the partition walls 21A, 21B, and 21C at a predetermined interval from the front surface of the heat insulating housing 20, and a downstream side of the capacitor 9 ( And a condenser fan 15 with a pair of left and right shrouds disposed on the rear side.

  Further, the space between the condenser fan 15 and the front surface of the heat insulating housing 20 is partitioned through partition walls 21A, 21B, and 21C, thereby forming an external airflow passage 22 through which the external air is circulated through the condenser 9. The external airflow passage 22 is opened in the vertical direction. For this reason, the outside air sucked from the front surface of the capacitor 9 by the capacitor fan 15 flows through the capacitor 9 and then blows out to the rear of the capacitor fan 15. (See the arrow in FIG. 4). The condenser fan 15 is integrated with a thin motor.

  In the capacitor unit 5, the oil separator 8 and the flow rate adjusting capillary tube 13 provided in the oil return pipe 14 are disposed on the external airflow passage 22. The oil separator 8 has a vertically long cylindrical shape, and is installed along the vertical direction on the outer airflow passage 22 at a corner formed by the front surface of the heat insulating housing 20 and the partition wall 21A. The capillary tube 13 is wound in a coil shape and installed on the front surface of the heat insulating housing 20.

  As shown in FIG. 5, the oil separator 8 and the capillary tube 13 do not interfere with the condenser fan 15 when rotating, and the condenser fan 15 does not interfere with the attachment or detachment of the condenser fan 15 from above during maintenance. It is arrange | positioned in the position away from 15 rotation areas.

  Furthermore, a unit cover 23 that covers the entire outside of the unit is attached to the outside of the heat insulating housing 20 and the capacitor unit 5. As shown in FIGS. 1 and 4, the unit cover 23 has a cross-sectional shape whose lower surface is obliquely cut from the freezer 2 side toward the front upper side, and the cabin 1 </ b> A of the refrigerated vehicle 1 is tilted. When it comes to not interfere. As shown in FIG. 2, the unit cover 23 has an outside air intake 24 facing the capacitor 9 of the capacitor unit 5 on the front surface, and the upper and lower surfaces of the unit cover 23 after the capacitor 9 is circulated. A discharge port 25 for discharging the water to the outside is opened.

  A space portion 26 is formed between the side surfaces of the heat insulating housing 20 and the partition walls 21A and 21C and the unit cover 23, and the expansion valve 10, refrigerant piping, and other refrigeration cycle components are formed in the space portion 26. Also, accessories such as control parts are arranged.

With the configuration described above, according to the present embodiment, the following operational effects can be obtained.
The transport refrigeration apparatus 3 is operated by turning on the clutch 4A and driving the compressor 4 via the traveling engine 1B. The high-temperature and high-pressure refrigerant gas compressed by driving the compressor 4 reaches the oil separator 8 through the discharge pipe 12A, where oil contained in the refrigerant gas is separated, and only the refrigerant gas is obtained. It is sent to the capacitor 9. In the condenser 9, heat is exchanged between the outside air taken in from the outside air intake port 24 of the unit cover 23 and the refrigerant by the condenser fan 15, and the refrigerant is condensed and liquefied. The outside air is changed in the vertical direction through the outside air passage 22 and is discharged from the outlet 25 of the unit cover 23 to the outside.

  The refrigerant condensed and liquefied by the condenser 9 is adiabatically expanded through the expansion valve 10 and then flows into the evaporator 11 where it is heat-exchanged with the air in the freezer 2 circulated through the evaporator fan 16. The refrigerant that is evaporated and gasified by heat exchange with the internal air is sucked into the compressor 4 through the suction pipe 12B, is compressed again, and circulates in the refrigeration cycle 7. The inside air is absorbed by the refrigerant and cooled, and blown out into the freezer 2 via the evaporator fan 16, so that the inside of the freezer 2 is cooled and kept cool.

  The oil separated from the refrigerant by the oil separator 8 is adjusted in flow rate by the capillary tube 13, is pressure-reduced to a low pressure, and returns to the suction pipe 12 </ b> B through the oil return pipe 14. The oil returned to the suction pipe 12 </ b> B is sucked into the compressor 4 together with the refrigerant gas and is used for lubrication of the sliding portion of the compressor 4. While this oil is returned to the compressor 4, it is heat-exchanged with the outside air in the oil separator 8 and the capillary tube 13 and cooled.

  That is, since the capillary tube 13 that forms part of the oil separator 8 and the oil return pipe 14 is disposed on the external airflow passage 22 of the capacitor unit 5 and is exposed to the external air flowing therethrough, the oil Heat is exchanged between the oil separator 8 and the outside air via a capillary tube 13 that forms part of the oil separator 8 and the oil return pipe 14, and then cooled. As a result, the high-temperature and high-pressure oil separated by the oil separator 8 is returned to the compressor 4 with its temperature and pressure being lowered to a low-temperature and low-pressure state.

  For this reason, the temperature of the oil separated by the oil separator 8 can be reduced and returned to the compressor 4 without providing additional parts such as an oil cooler, and the refrigerant gas and oil sucked into the compressor 4 can be reduced. The temperature can be reduced and the refrigerant discharge temperature of the compressor 4 can be suppressed. Therefore, it is possible to suppress the deterioration of oil and the sealing material that are easily accelerated in a high temperature environment, and to improve the durability and reliability of the product.

  Further, since the refrigerant sucked into the compressor 4 is not exposed to the high-temperature oil, the suction superheat degree of the refrigerant can be suppressed, the suction efficiency (compression efficiency) can be increased, and the refrigerating capacity can be improved. Furthermore, since the oil temperature can be reduced without adding an oil cooler or the like, the expected refrigeration performance can be exhibited without increasing costs or adding additional parts.

  Also, the capillary tube 13 that forms part of the oil separator 8 and the oil return pipe 14 is disposed at a corner away from the rotation area of the condenser fan 15 on the external airflow passage 22 defined by the partition wall 21A. Therefore, the rotation of the condenser fan 15 is not obstructed, and it does not interfere with the attachment / detachment of the condenser fan 15 from above during maintenance. Therefore, the maintenance of the condenser fan 15 and the like is not hindered.

Furthermore, since the oil separator 8 has a vertically long cylindrical shape, the oil separator 8 can be accommodated along a vertical direction on a corner on the external airflow passage 22 partitioned by the partition wall 21A. Therefore, the oil separator 8 can be easily installed even in a relatively narrow space.
In the present embodiment, both the oil separator 8 and the capillary tube 13 that forms part of the oil return pipe 14 are disposed on the external airflow passage 22, but either one is disposed on the external airflow passage 22. It is good also as a structure which has arrange | positioned and arrange | positioned the other in the space part 26, and the effect similar to the above is show | played by this.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
The present embodiment is different from the first embodiment in the configuration of the partition walls 21D and 21E. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, for the purpose of increasing the strength, the partition walls 21D and 21E have a larger distance between the partition walls 21D and 21E on the heat insulating housing 20 side than on the front end side, as shown in FIG. It is provided diagonally so as to be. In this case, since the oil separator 8 has a vertically long cylindrical shape, the oil separator 8 can be disposed at the deepest corner formed by an acute angle formed by the partition wall 21 </ b> D and the front surface of the heat insulating housing 20.

  As described above, when the partition walls 21 </ b> D and 21 </ b> E are provided obliquely for the purpose of increasing the strength, an oil separator is provided on the external airflow passage 22 using an acute angle formed by the partition wall 21 </ b> D and the heat insulating housing 20. 8 can be provided. For this reason, the space for disposing the oil separator 8 can be relatively easily ensured in a narrow space. In the present embodiment, the capillary tube 13 is installed in the heat insulating housing 20 as in the first embodiment, but the capillary tube 13 may be installed on the partition wall 21D side.

  In addition, this invention is not limited to the invention concerning the said embodiment, In the range which does not deviate from the summary, it can change suitably. For example, in the above embodiment, the refrigeration cycle 7 has a simplified form in which a receiver, a dryer, a subcooler, an accumulator, and the like are omitted, but the present invention is provided with these devices as needed. It goes without saying that a refrigeration unit is included. The oil separator 8 and the capillary tube 13 are disposed at one corner of the partition wall 21A or 21D and the heat insulating housing 20, but are disposed at one corner between the other partition walls 21B, 21C, and 21E. Of course, you may.

  Furthermore, in the above embodiment, the example in which the capillary tube 13 is provided as the flow rate adjusting means of the oil return pipe 14 has been described. However, this flow rate adjusting means can be replaced by a fixed throttle or an expansion valve other than the capillary tube 13. Is possible. Further, the partition walls 21A to 21E do not need to be partition walls that completely partition between the external airflow passage 22 and the space portion 26 or between the plurality of external airflow passages 22, and have openings or the like in part. Such a partition wall may be used, and such an embodiment is naturally included in the present invention. In the present invention, it is added that the term “oil return pipe 14” may be used to include flow rate adjusting means such as a capillary tube 13, a fixed throttle, an expansion valve, and the like.

It is a side view of the front part of the refrigeration vehicle carrying the refrigeration equipment for transportation concerning a 1st embodiment of the present invention. It is a front view of the transport refrigeration apparatus shown in FIG. It is a top view which shows the apparatus arrangement configuration of the transport refrigeration apparatus shown in FIG. It is a right view which shows the apparatus arrangement configuration of the transport refrigeration apparatus shown in FIG. It is a front view which shows the arrangement configuration of the oil separator with respect to the capacitor | condenser fan of the transport refrigeration apparatus shown in FIG. FIG. 3 is a refrigeration cycle diagram of the transport refrigeration apparatus shown in FIG. 2. It is a top view which shows the equipment arrangement structure of the transport refrigeration apparatus which concerns on 2nd Embodiment of this invention.

Explanation of symbols

2 Freezer 2A Front wall 3 Transport refrigeration unit 5 Capacitor unit 6 Evaporator unit 8 Oil separator 9 Capacitor 13 Capillary tube 14 Oil return pipe 15 Capacitor fan 20 Thermal insulation housing 21A, 21B, 21C, 21D, 21E Partition wall 22 External airflow passage

Claims (6)

A heat insulating housing that can be attached to the outer surface wall of the freezer, an evaporator unit disposed on the inner side of the heat insulating housing, and a capacitor unit disposed on the outer front surface of the heat insulating housing, the capacitor unit comprising: A capacitor is installed in front of the heat insulating housing through a partition wall provided on both the left and right sides of the heat insulating housing, and a capacitor fan is installed behind the capacitor wall. In the transport refrigeration apparatus configured to discharge the outside air sucked from the condenser in the vertical direction after passing through the condenser and through the external airflow passage formed at the interval,
An oil separator that is provided in a discharge pipe from a compressor on the external airflow passage through which the outside air is circulated through the condenser, and that separates the oil in the refrigerant gas, or the oil separated by the oil separator A refrigeration apparatus for transportation, wherein at least one of oil return pipes returning to the suction pipe side is provided.   2. The transport refrigeration apparatus according to claim 1, wherein both the oil separator and the oil return pipe are disposed on the external airflow passage.   The oil return pipe includes any one of a capillary tube, a fixed throttle, and an expansion valve, and one of the capillary tube, the fixed throttle, and the expansion valve is disposed on the external airflow passage. Item 3. The transport refrigeration apparatus according to Item 1 or 2.   2. The oil separator and / or the oil return pipe are disposed at a corner away from a rotation area of the condenser fan on the external airflow passage partitioned by the partition wall. 4. The transport refrigeration apparatus according to any one of items 3 to 3.   The partition wall is provided obliquely so that a space between the left and right partition walls is widened from the front end side toward the heat insulating housing side, and the oil separation is performed at a corner formed by the partition wall and the heat insulating housing. The transport refrigeration apparatus according to any one of claims 1 to 4, wherein a container and / or the oil return pipe are disposed. The transport refrigeration apparatus according to any one of claims 1 to 5, wherein the oil separator has a vertically long cylindrical shape.

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