JP2010236829A - Refrigerating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive refrigerating device preventing outflow of lubricating oil to a halt side compressor during operation of a main compressor and reducing a suction pressure loss so as to improve a refrigerating capacity. <P>SOLUTION: In the refrigerating device 1, a first compressor 2 and a second compressor 3 operated separately one by one via an accumulator 9 having a plurality of refrigerant outflow pipes 15, 16 are connected to a refrigerating cycle in parallel, and the first compressor 2 and the second compressor 3 serve as the main compressor with high use frequency and a stand-by compressor with low use frequency, respectively. The first refrigerant outflow pipe 15 out of the plurality of refrigerant outflow pipes 15, 16 is structured of a U-tube having an oil return hole 17 formed in a lower portion, and is connected to suction piping 10A of the first compressor 2. The second refrigerant outflow pipe 16 is structured of an outflow pipe connected to the upper part of the accumulator 9 and having no liquid trap part, and is connected to suction piping 10B of the second compressor 3. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention is a refrigeration apparatus in which a plurality of compressors connected in parallel to one refrigeration cycle are operated independently one by one, and particularly applied to a transport refrigeration apparatus mounted on a refrigeration vehicle or the like. Thus, the present invention relates to a suitable refrigeration apparatus.

  As one of the transport refrigeration apparatuses mounted on the refrigeration vehicle, there is a direct connection type refrigeration apparatus in which a compressor is driven by a traveling engine of the vehicle. When the vehicle is running, this refrigeration device can be cooled by driving the compressor with the running engine. However, when the vehicle is parked, the normal running engine is used. It has stopped. For this reason, a standby electric compressor driven by a commercial power source is installed separately from the main compressor driven by the traveling engine, so that the pre-cooling operation and the cold insulation operation can be performed even when the traveling engine is stopped. Yes.

  In the above refrigeration apparatus, since a plurality of compressors that are operated individually in one refrigeration cycle are connected in parallel, the lubricating oil circulating with the refrigerant in the refrigeration cycle is operated during operation. Unless the oil is returned only to the compressor on the other side, there may be a situation where the lubricating oil becomes insufficient with the passage of time, particularly during operation of the main compressor that is frequently used. In order to cope with such a problem, a common accumulator having a plurality of U-shaped tubes having oil return holes is installed on the suction side of a plurality of compressors, and the plurality of compressors are connected in parallel via the accumulators. What has been connected has been proposed (see, for example, Patent Document 1).

  However, in the above configuration, when the compressor in operation is stopped, the refrigerant in the evaporator moves to both the compressor on the operation side and the compressor on the pause side to balance the pressure. The lubricating oil trapped in the suction piping system including the U-shaped tube of the resting compressor is moved into the resting compressor by the refrigerant flow at that time. Under such circumstances, only the main compressor driven by the traveling engine is rarely used for a long period of time, and in this case, the main compressor may run out of lubricating oil. As countermeasures, as shown in Patent Document 2, a shut-off valve is provided in a suction pipe of a standby compressor that is used infrequently, or as shown in Patent Document 3, each compressor is provided downstream of an accumulator. There is provided a suction volume portion located at a lower portion of the compressor, and the compressors connected in parallel via the suction volume portion (suction side header).

International Publication No. 2002/073036 Pamphlet (see FIGS. 10 to 12) Japanese Patent Laid-Open No. 11-281202 (see FIG. 1) JP 2004-93027 A (see FIG. 2)

However, as shown in Patent Document 2, if a shut-off valve is provided in the suction pipe, an increase in suction pressure loss is unavoidable, and there is a problem that the refrigerating capacity is reduced by that amount, and the suction pipe has a large diameter. On the other hand, there has been a problem that a shut-off valve having a large diameter has to be provided, resulting in high costs.
In addition to the accumulator, the one disclosed in Patent Document 3 has a structural limitation that a suction volume portion must be installed in the lower portion of each compressor, and a plurality of compressors are installed in the vertical direction. There is a problem that it cannot be substantially applied to a refrigeration apparatus installed in a remote location.

  The present invention has been made in view of such circumstances, and the main compressor can prevent the outflow of lubricating oil to the idle side compressor during operation, and can reduce the suction pressure loss and improve the refrigerating capacity. An object is to provide a low-cost refrigeration apparatus that can be achieved.

In order to solve the above-described problems, the refrigeration apparatus of the present invention employs the following means.
That is, a refrigeration apparatus according to the present invention includes an accumulator having a plurality of refrigerant outflow pipes, and a plurality of first compressors and second compressors that are operated independently one by one through the accumulator are refrigeration cycles. In the refrigerating apparatus, the first compressor is a main compressor having a high use frequency and the second compressor is a standby compressor having a low use frequency. The first refrigerant outflow pipe is constituted by a U-shaped pipe provided with an oil return hole in a lower part, and is connected to the suction pipe of the first compressor, and the second refrigerant outflow pipe is connected to the accumulator. It is comprised by the outflow pipe | tube which does not have the liquid trap part connected to the upper part, and is connected to the suction piping of the said 2nd compressor.

  In a refrigeration system in which a plurality of compressors are operated independently one by one, each time the compressor on the operation side is stopped, the refrigerant flows to the compressor on the suspension side when the pressure is balanced, If the lubricating oil trapped in the suction piping system is moved into the idle side compressor along with the refrigerant flow and is repeated, there is a possibility that the lubricating oil in the operating side compressor is insufficient. According to the present invention, the first refrigerant outflow pipe is constituted by a U-shaped pipe provided with an oil return hole in a lower portion, connected to the suction pipe of the first compressor, and the second refrigerant outflow pipe is The first compressor, which is the main compressor that is frequently used, is operated because it is composed of an outflow pipe that does not have a liquid trap part connected to the upper part of the accumulator and is connected to the suction pipe of the second compressor. Even if the refrigerant flows into the standby second compressor where the refrigerant is stopped due to the pressure balance, the lubricating oil is not repeatedly discharged from the accumulator to the second compressor on the suspension side. Even without providing a shut-off valve, it is possible to prevent the lubricating oil from flowing out to the second compressor on the pause side. Therefore, the first compressor, which is the main compressor that is frequently used, does not suffer from poor lubrication due to lack of lubricating oil, and the reliability can be improved. In addition, there is no increase in the suction pressure loss due to the provision of the shutoff valve, the refrigeration capacity can be improved correspondingly, and the cost can be reduced by omitting the shutoff valve.

  Furthermore, the refrigerating apparatus of the present invention is characterized in that, in the refrigerating apparatus, the second refrigerant outflow pipe is connected to a lower portion of the accumulator by an oil return pipe having a solenoid valve at a lower portion than the accumulator. And

  According to the present invention, since the second refrigerant outflow pipe is connected to the lower part of the accumulator by the oil return pipe having the electromagnetic valve at a lower part than the accumulator, the second refrigerant outflow pipe is a standby compressor that is less frequently used. When operating the compressor, by opening the solenoid valve, the lubricating oil separated by the accumulator through the oil return pipe can be returned little by little to the suction pipe side by gravity and sucked into the second compressor. Therefore, it is not necessary to ensure a head difference for sucking oil from the accumulator, and the suction pipe can be designed to be thicker by that amount, so that the suction pressure loss can be reduced and the refrigerating capacity can be improved. The oil return pipe and the solenoid valve may be thin pipes and small solenoid valves that can return a small amount of oil.

  Furthermore, in the refrigeration apparatus of the present invention, in any one of the refrigeration apparatuses described above, the second refrigerant outflow pipe is provided with a rising portion that is raised above an opening end that is opened in the accumulator. It is characterized by.

  According to the present invention, the second refrigerant outflow pipe is provided with the rising portion that is raised above the opening end that is opened in the accumulator, so that the second refrigerant outflow pipe opened in the accumulator Oil that tends to flow out from the open end to the second compressor side can be blocked by the rising portion. Accordingly, it is possible to more reliably prevent the lubricating oil from flowing into the second compressor on the pause side.

  Further, the refrigeration apparatus of the present invention is the open refrigeration apparatus driven by a mist lubrication type engine in which the first compressor is lubricated by oil droplets circulating in the refrigeration cycle together with the refrigerant in any one of the above refrigeration apparatuses. The second compressor is an electric compressor that is driven by a commercial power source of a forced lubrication system that forcibly supplies and lubricates oil stored in an oil reservoir. .

  According to the present invention, the first compressor is an open type compressor driven by a mist lubrication type engine lubricated by oil droplets circulating in the refrigeration cycle together with the refrigerant, and the second compressor is an oil sump. Therefore, when the first compressor, which is the main compressor, is in operation, the amount of oil circulated in the refrigeration cycle is forcibly supplied and lubricated. As a matter of course, this oil can be prevented from flowing out into the second compressor on the idle side in the suction piping system from the accumulator to the compressor and collecting in the second compressor as described above. . Therefore, it is possible to secure a sufficient amount of lubricating oil circulating in the refrigeration cycle while the first compressor of the main compressor is in operation, eliminating the possibility that the first compressor will be poorly lubricated and reliable. It is possible to improve the performance.

  According to the present invention, every time the first compressor, which is the main compressor that is frequently used, is stopped during operation, even if the refrigerant flows to the second compressor for standby that is stopped due to pressure balance, the accumulator The lubricating oil is not repeatedly discharged from the second compressor to the idle side second compressor, and it is possible to prevent the lubricating oil from flowing out to the idle second compressor without providing a shut-off valve. The first compressor, which is the main compressor having a high frequency, does not fall into poor lubrication due to lack of lubricating oil, and the reliability can be improved. In addition, there is no increase in the suction pressure loss due to the provision of the shutoff valve, the refrigeration capacity can be improved correspondingly, and the cost can be reduced by omitting the shutoff valve.

It is a refrigerant circuit figure of the refrigerating device concerning a 1st embodiment of the present invention. FIG. 2 is an enlarged view around an accumulator of the refrigeration apparatus shown in FIG. 1. It is an enlarged view around the accumulator of the freezing apparatus concerning 2nd Embodiment of this invention.

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 FIG.
FIG. 1 shows a refrigerant circuit diagram of the refrigeration apparatus according to the first embodiment of the present invention. The refrigeration apparatus 1 is a direct-coupled transport refrigeration apparatus mounted on a refrigeration vehicle, and includes two first compressors 2 and a second compressor 3 that compress refrigerant and a fan 4 and is compressed. A condenser 5 that condenses and liquefies high-temperature and high-pressure refrigerant gas, an expansion valve 6 that adiabatically expands the liquefied high-pressure refrigerant to form a low-pressure gas-liquid two-phase refrigerant, and a fan 7 are provided, and the gas-liquid two-phase refrigerant is evaporated. And an accumulator 9 that separates the liquid component in the evaporated low-pressure refrigerant gas and sucks only the gas refrigerant into the first and second compressors 2 and 3, and is sequentially connected by the refrigerant pipe 10. The refrigeration cycle 11 is provided.

  The first compressor 2 is a main compressor that is installed in an engine room of a refrigeration vehicle and is driven by an engine 12 for driving a vehicle via an electromagnetic clutch 13, and a housing in which a compression mechanism is accommodated. An open type compressor that does not have a drive source and can be reduced in size and weight is employed. As is well known, the open type compressor has a structure in which a drive shaft projects from the housing to the outside, and is driven by obtaining power from the traveling engine 12 by the intermittent connection of an electromagnetic clutch 13 provided on the drive shaft. It has become. Further, in the first compressor 2, the lubricating oil dissolved in the refrigerant is circulated in the refrigeration cycle 11 together with the refrigerant, and the first compressor 2 is slid by the mist-like lubricating oil contained in the intake refrigerant gas. A known mist lubrication method for lubricating the portion is employed.

  The second compressor 3 is a standby compressor that is installed in a space under the chassis of the vehicle and is operated at the time of pre-cooling operation or cooling operation in which the traveling engine 12 is stopped. The electric compressor with a built-in motor is driven by an electric motor that uses electric power obtained from the power supply cable 14 as a drive source. The standby compressor 3 may be a hermetic or semi-hermetic electric compressor having an electric motor built in a housing. The standby compressor 3 is lubricated by a known forced lubrication in which an oil sump is provided in the compressor housing, and the lubricating oil filled in the oil sump is forcibly supplied to a sliding portion by a pump or the like for lubrication. The method is adopted.

  The first compressor 2 and the second compressor 3 are not operated at the same time, but are operated independently one by one. Check valves 20 and 21 are provided in the first discharge pipe 10C and the second discharge pipe 10D connected to the two first compressors 2 and the second compressor 3, respectively. Further, the first discharge pipe 10C and the second discharge pipe 10D are connected to the second compressor 3 as a standby compressor from the first compressor 2 side as the main compressor on the downstream side of the check valves 20 and 21. In order to prevent the oil from flowing out to the side, for example, they are merged as follows.

  The first discharge pipe 10 </ b> C from the first compressor 2 is arranged vertically upward in the vicinity of the junction including the check valve 20, and the check valve 21 with respect to the first upward discharge pipe 10 </ b> C. The vicinity of the merge portion including the check valve 21 of the second discharge pipe 10D from the second compressor 3 is merged from the horizontal direction to the horizontal direction on the downstream side. A rising portion 22 having a predetermined height H is provided on the upstream side of the check valve 21 in the second discharge pipe 10D.

  The condenser 5 is installed outside the refrigerator mounted on the refrigerator car and is a heat exchanger for exchanging heat between the outside air blown through the fan 4 and the traveling wind and the refrigerant, and cools the refrigerant. It is responsible for the function of condensing and liquefying. The evaporator 8 is installed inside the refrigerator or facing the refrigerator, and is a heat exchanger for exchanging heat between the internal air circulated through the fan 7 and the refrigerant. It bears the function of cooling the air.

  Further, as shown in FIG. 2, the accumulator 9 includes a refrigerant pipe 10 from the evaporator 8 connected to the upper part, and includes two first refrigerant outflow pipes 15 and a second refrigerant outflow pipe 16. Yes. The two first refrigerant outflow pipes 15 and the second refrigerant outflow pipes 16 are connected to two suction pipes 10A and 10B of the first compressor 2 and the second compressor 3, respectively. The first compressor 2 and the second compressor 3 are connected in parallel to each other via an accumulator 9 common to the refrigeration cycle 11.

  The first refrigerant outflow pipe 15 is configured by a U-shaped pipe 15A having an oil return hole 17 provided at the lowest position, and sucks oil from the oil return hole 17 little by little, and the U-shaped pipe 15A and the suction pipe The lubricating oil is returned to the side of the first compressor 2 that is operating through 10A. The second refrigerant outflow pipe 16 is an outflow pipe that does not have a trap portion connected to the upper part of the accumulator 9. The second refrigerant outflow pipe 16 has an opening that opens into the accumulator 9. A rising portion 16B that is raised upward by a height h with respect to the end 16A is provided.

  Further, an oil return pipe 19 having an electromagnetic valve 18 having one end 19 </ b> A communicating with the lower part of the accumulator 9 is connected to the second refrigerant outflow pipe 16 at a position below the bottom of the accumulator 9. . One end 19A of the oil return pipe 19 is inserted into the accumulator 9, and is opened at a position substantially equal to the oil return hole 17 provided in the U-shaped pipe 15A. The electromagnetic valve 18 is opened when the second compressor 3 is in operation.

With the configuration described above, according to the present embodiment, the following operational effects can be obtained.
While the refrigerated vehicle is traveling, the first compressor 2 of the main compressor is driven through the traveling engine 12, while in the standby state where the traveling engine 12 is stopped while the vehicle is parked, the commercial power supply The second compressor 3 for standby is driven. High-temperature and high-pressure refrigerant compressed by the first compressor 2 or the second compressor 3 and discharged to the refrigeration cycle 11 side through the first discharge pipe 10C, the check valve 20 or the second discharge pipe 10D, and the check valve 21 The gas is cooled by the condenser 5 to be condensed and liquefied, and then decompressed by the expansion valve 6 to become a low-pressure gas-liquid two-phase refrigerant and supplied to the evaporator 8.

  This refrigerant exchanges heat with the cooler air circulated by the fan 7 in the evaporator 8 and absorbs heat from the cooler air to evaporate. As a result, the internal air is cooled and used for cooling in the refrigerator. The gas refrigerant evaporated in the evaporator 8 flows into the accumulator 9, and after the liquid components (liquid refrigerant and lubricating oil) contained in the refrigerant are separated, only the gas refrigerant is either the refrigerant outflow pipe 15 or 16. Is sucked into the first compressor 2 or the second compressor 3 through the suction pipe 10A or 10B and compressed again. By repeating this, the inside of the refrigerator is cooled.

  During the cooling operation described above, while the first compressor 2 of the main compressor is in operation, the first compressor 2 is lubricated by the mist-like lubricating oil circulated in the refrigeration cycle 11 together with the refrigerant. Lubricating oil circulated in the refrigeration cycle 11 is separated in the accumulator 9 and then sucked into the first compressor 2 by a certain amount from an oil return hole 17 provided in the lowermost part of the U-shaped tube 15A. The first compressor 2 is used for lubrication.

  Further, when performing the pre-cooling operation or the cold-retaining operation in the standby state, the operation is performed by driving the second compressor 3 for standby using a commercial power source as a drive source. Also in this case, the lubricating oil is separated in the accumulator 9 and returned to the second compressor 3 by a certain amount via the electromagnetic valve 18 and the oil return pipe 19.

  On the other hand, when the first compressor 2, which is the main compressor, is stopped during operation, the high and low pressures in the refrigeration cycle are pressure balanced each time, so the second compressor in which the refrigerant in the evaporator is stopped Also flows to the 3rd side. At this time, the oil accumulated in the second refrigerant outflow pipe 16 and the suction pipe 10B reaching the second compressor 3 flows out into the second compressor 3 on the pause side along with the flow of the refrigerant. If the lubricating oil accumulates in the second compressor 3 on the idle side by repeating this, the first compressor 2 side will be short of lubricating oil. However, in the present embodiment, the second refrigerant outflow pipe 16 to which the second compressor 3 of the accumulator 9 is connected has no trap portion and does not collect oil. Lubricating oil does not flow out from the refrigerant outflow pipe 16 to the second compressor 3 on the pause side through the suction pipe 10D.

  For this reason, every time the first compressor 2 of the main compressor that is frequently used is stopped during operation, even if the refrigerant flows into the second compressor 3 for standby due to pressure balance, the second compression is performed from the accumulator 9. Lubricating oil trapped in the suction piping system up to the machine 3 is not repeatedly discharged to the second compressor 3 on the pause side, and even if no shutoff valve is provided, the lubricant to the second compressor 3 on the pause side The outflow of the lubricating oil can be prevented. Therefore, the first compressor 2, which is a main compressor that is frequently used, does not fall into poor lubrication due to lack of lubricating oil, and the reliability can be improved. In addition, there is no increase in the suction pressure loss due to the provision of the shutoff valve, the refrigeration capacity can be improved correspondingly, and the cost can be reduced by omitting the shutoff valve.

  Further, the second refrigerant outflow pipe 16 connected to the second compressor 3 for standby is connected to the lower part of the accumulator 9 and the oil return pipe 19 having the electromagnetic valve 18 at a position below the bottom of the accumulator 9. Yes. For this reason, when operating the second compressor 3, which is a low-use standby compressor, the lubricating oil separated by the accumulator 9 through the oil return pipe 19 by opening the electromagnetic valve 18 is gradually collected by gravity. It can return to the 2nd refrigerant | coolant outflow pipe | tube 16 and the suction piping 10D side, and can be made to inhale by the 2nd compressor 3. FIG. Accordingly, there is no need to secure a head difference for sucking oil from the accumulator 9, and the suction pipe 10D can be designed to be thicker by that amount, so that the suction pressure loss can be reduced and the refrigerating capacity can be improved.

  Further, the second refrigerant outflow pipe 16 is provided with a rising portion 16B that is raised upward by a height h from the opening end 16A opened in the accumulator 9. For this reason, oil that tends to flow out from the open end 16A of the second refrigerant outflow pipe 16 that opens into the accumulator 9 to the second compressor 3 side is blocked by the rising portion 16B and returned to the accumulator 9. it can. Accordingly, it is possible to more reliably prevent the lubricating oil from flowing out to the second compressor 3 on the pause side.

  The first compressor 2 is an open type compressor driven by a mist lubrication engine 12 lubricated by oil droplets circulating in the refrigeration cycle 11 together with the refrigerant, and the second compressor 3 is an oil reservoir. This is an electric compressor of a forced lubrication system in which oil is forcedly lubricated and lubricated. For this reason, while the first compressor 2 which is the main compressor is in operation, the amount of oil circulating in the refrigeration cycle 11 inevitably increases. However, this oil is sucked from the accumulator 9 to the compressor. As described above, it can be prevented that the refrigerant flows out into the second compressor 3 on the pause side and accumulates in the second compressor 3 as described above. Therefore, during operation of the first compressor 2 of the main compressor that is frequently used, the amount of lubricating oil circulating in the refrigeration cycle 11 can be sufficiently secured, and the first compressor 2 falls into poor lubrication. The possibility can be eliminated and the reliability can be improved.

  Furthermore, since the traveling compressor driven first compressor 2 installed in the narrow engine room of the refrigeration vehicle uses a mist lubricated open compressor that can be made compact, it can be installed in a narrow space. It is easy to improve the mountability of the refrigeration apparatus 1, and the forced lubrication system with an oil sump inside the second compressor 3 for standby installed in a relatively ample space such as below the chassis. Since the hermetic electric compressor is used, it goes without saying that effects such as ensuring the reliability of the lubricating performance can be obtained.

[Second Embodiment]
Next, a second embodiment of the present invention will be described with reference to FIG.
The present embodiment differs from the first embodiment described above in the configuration of the second refrigerant outflow pipe 26. Since other points are the same as those in the first embodiment, description thereof will be omitted.
In the present embodiment, as shown in FIG. 3, the second refrigerant outflow pipe 26 is connected to the upper side portion of the accumulator 9 from the lateral direction. The second refrigerant outflow pipe 26 is connected with an upward slope as shown by a broken line, and a rising portion 26B having a height h is formed with respect to the opening end 26A opened in the accumulator 9. You may connect as follows.

  By adopting the configuration as described above, it is possible to obtain substantially the same operational effects as those of the first embodiment, and the second refrigerant outlet pipe 16 or 26 is arranged on the upper side or side of the accumulator 9 in accordance with the convenience of the piping. It becomes possible to selectively connect to any of the sections.

  The present invention is not limited to the invention according to the above-described embodiment, and can be appropriately modified without departing from the gist thereof. For example, in the above embodiment, the accumulator 9 has been described as an example of a relatively large-diameter single-cylinder accumulator 9. However, two cylinders having a smaller diameter are coupled so as to communicate vertically. It is good also as a double-bottle type accumulator comprised. Moreover, about the 1st compressor 2 and the 2nd compressor 3, you may use the compression mechanism of what kind of structures, such as a reciprocating, a rotary, a scroll, a screw.

  Furthermore, in the above-described embodiment, an example in which a mist lubrication type compressor is employed as the first compressor 2 and a forced lubrication type compressor is employed as the second compressor 3 has been described. However, the present invention is not limited to the above combinations, and is naturally effective in any combination of compressors of the lubrication system.

1 Refrigeration Equipment 2 First Compressor (Main Compressor)
3 Second compressor (Standby compressor)
9 Accumulator 10A, 10B Suction pipe 11 Refrigeration cycle 12 Engine 14 Power cable 15 First refrigerant outflow pipe 15A U-shaped pipe 16, 26 Second refrigerant outflow pipe 16A, 26A Open end 16B, 26B Start-up part 17 Oil return hole 18 Electromagnetic Valve 19 Oil return pipe

Claims (4)

An accumulator having a plurality of refrigerant outflow pipes is provided, and a plurality of first compressors and second compressors that are independently operated via the accumulator are connected in parallel to the refrigeration cycle, and the first compression In the refrigeration apparatus in which the machine is a main compressor that is used frequently, and the second compressor is a standby compressor that is used less frequently,
The first refrigerant outflow pipe in the plurality of refrigerant outflow pipes is configured by a U-shaped pipe provided with an oil return hole in a lower portion, connected to the suction pipe of the first compressor, and second The refrigerant outflow pipe is constituted by an outflow pipe not having a liquid trap portion connected to an upper portion of the accumulator, and is connected to an intake pipe of the second compressor.   2. The refrigeration apparatus according to claim 1, wherein the second refrigerant outflow pipe is connected to a lower portion of the accumulator and an oil return pipe having an electromagnetic valve at a lower portion than the accumulator.   The refrigeration apparatus according to claim 1 or 2, wherein the second refrigerant outflow pipe is provided with a rising portion that is raised above an opening end that is opened in the accumulator. The first compressor is an open type compressor driven by a mist lubrication type engine lubricated by oil droplets circulating in the refrigeration cycle together with a refrigerant, and the second compressor is stored in an oil reservoir. 4. The refrigeration apparatus according to claim 1, wherein the refrigeration apparatus is an electric compressor driven by a commercial power source of a forced lubrication system for forcibly refueling and lubricating oil.

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