JP2015158317A - Air conditioning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve reliability of a compressor by an accumulator supplying a proper amount of oil to the compressor.SOLUTION: A refrigerant and a refrigerating machine oil enclosed in a refrigeration cycle are composed with physical properties that a low temperature-side two-layer separation temperature is higher than -20°C in a state that an oil concentration to the refrigerant is within a range of 20-50%. An accumulator includes an oil inflow pipe to which oil separated by an oil separator flows, a refrigerant inflow pipe to which a refrigerant flows, an oil storage portion for storing oil flowing therein from the oil inflow pipe, a liquid refrigerant storage portion for storing a liquid refrigerant flowing therein from the refrigerant inflow pipe separately from the oil storage portion, an oil return pipe having an opening for sucking the oil stored in a bottom portion of the oil storage portion and allowing the oil to flow upward, and a refrigerant return pipe having an opening for sucking the liquid refrigerant stored in a bottom portion of the liquid refrigerant storage portion and allowing the liquid refrigerant to flow upward. The refrigerant return pipe and the oil return pipe are joined, and the refrigerant from the refrigerant inflow pipe flows to the refrigerant return pipe or the oil return pipe.

Description

  The present invention relates to an air conditioner.

Conventionally, an air conditioner including an oil separator and an accumulator as shown in Patent Document 1 (Japanese Patent Laid-Open No. 2010-203733) is known. The refrigeration cycle during the cooling operation of this conventional air conditioner will be described with reference to FIG.
The air conditioner of FIG. 10 includes an outdoor unit 30 and an indoor unit 31, and here, an example in which two indoor units are connected to one outdoor unit 30 by a liquid pipe 13 and a gas pipe 12. Is shown.

  In this air conditioner, the refrigerant compressed and discharged by the compressor 1 during the cooling operation is separated into oil by the oil separator 5 and then flows into the outdoor heat exchanger 3 via the four-way valve 2. The four-way valve 2 switches the refrigerant flow between the cooling operation and the heating operation. When the refrigerant flows through the outdoor heat exchanger 3, the refrigerant is condensed and liquefied by exchanging heat with outdoor air blown by the outdoor fan 4. The condensed liquid refrigerant flows into the liquid pipe 13 through the outdoor expansion valve 8 and is sent to the indoor unit 31.

  The liquid refrigerant flowing into the indoor unit 31 is decompressed by the indoor expansion valve 18 to become a low-temperature / low-pressure gas-liquid mixed refrigerant and flows into the indoor heat exchanger 16. In the indoor heat exchanger 16, the gas-liquid mixed refrigerant evaporates by exchanging heat with the indoor air blown by the indoor fan 17, becomes a gas refrigerant, flows out of the indoor unit 31 to the gas pipe 12, and flows to the outdoor unit 30. The gas refrigerant flowing into the outdoor unit 30 through the gas pipe connection port 6 passes through the four-way valve 2 and flows into the accumulator 40 through the inlet pipe 25.

  On the other hand, part of the oil discharged together with the refrigerant from the compressor 1 is separated from the refrigerant by the oil separator 5, passes through the bypass circuit 24 and joins the refrigerant inlet pipe 25, and then returns to the accumulator 40. The oil that has not been separated by the oil separator 5 passes through the outdoor heat exchanger 3, the liquid pipe 13, the indoor unit 31, and the gas pipe 12 and then from the inlet pipe 25 to the accumulator 40 in the same manner as the refrigerant flow. In order to flow in, the refrigerant and oil returning from the indoor heat exchanger 16 are mixed and flow into the accumulator 40.

FIG. 11 shows a conventional accumulator 40 disclosed in Patent Document 1. A U-shaped pipe 52 is accommodated in the accumulator 40, one end of the U-shaped pipe 52 opens upward in the accumulator 40, and the other end is connected to the suction pipe 22 of the compressor 1. The refrigerant flowing into the accumulator 40 from the refrigerant inflow pipe 27 is mixed with oil, and the gas refrigerant and the oil are separated in the accumulator 40, and the oil accumulates at the bottom. At this time, the liquid refrigerant may be mixed with the refrigerant flowing into the accumulator 40. In this case, the liquid refrigerant and the oil are mixed and accumulated at the bottom. When a large amount of liquid refrigerant returns to the compressor 1, liquid compression may occur in the compressor 1. Since this causes a failure of the compressor 1, the accumulator 40 plays a role of a buffer that suppresses the amount of liquid refrigerant returning to the compressor 1.
On the other hand, the compressor 1 needs to return an appropriate amount of oil to lubricate the sliding portion inside, and in the accumulator 40, in order to return this appropriate amount of oil, a first bent portion located in the lower portion of the accumulator 40 is placed first. The oil return hole 70 is provided. When the gas refrigerant flows in from the upper opening of the U-shaped pipe 52 and flows into the suction pipe 22 on the other end side, the gas refrigerant is compressed in a state containing oil by sucking oil from the oil return hole 70. It flows to the machine 1. When the liquid refrigerant is mixed, the liquid refrigerant and the oil are mixed and accumulated at the bottom. In this case, the first oil return hole is formed when the gas refrigerant flows through the U-shaped pipe 52. The mixed liquid refrigerant and oil are sucked from 70 and flow into the suction pipe 22 of the compressor 1 together with the gas refrigerant.

  In addition, a second oil return hole 71 is formed in the U-shaped pipe 52 above the first oil return hole 70, and the second oil return hole 71 rises when the oil level at the bottom of the accumulator 40 rises. By sucking oil from the oil return hole 71 as well, the oil returning to the compressor 1 is prevented from being insufficient. Also in this case, if the liquid refrigerant is mixed, the mixed liquid refrigerant and oil are sucked from both the first oil return hole 70 and the second oil return hole 71, and together with the gas refrigerant, the compressor 1 It flows into the suction pipe 22.

  When the compressor 1 is stopped, liquid refrigerant and oil are accumulated in the U-shaped pipe 52, and both the first oil return hole 70 and the second oil return hole 71 are liquid refrigerant and oil. When the compressor 1 is full, a large amount of liquid refrigerant or oil may return to the compressor 1 at a time when the compressor 1 is started and liquid compression may occur. Therefore, a pressure equalizing hole 76 is formed further above the second oil return hole 71, so that the gas refrigerant can be always returned at the same time during startup.

  In recent years, HFC-based refrigerants that have a high effect on suppressing global warming have been used in air conditioners. Since the HFC refrigerant has a polar molecular structure, it is not compatible with conventionally used mineral oil. Therefore, refrigerating machine oils that incorporate polar bonds in the refrigerating machine oil molecules and are compatible with HFC refrigerants have been developed. Specific examples include polyol ester (POE) and polyvinyl ether (PVE).

  However, even if the refrigerating machine oil is compatible with the HFC refrigerant, the low temperature side two-layer separation temperature may actually be high. In such a combination, the first oil return hole 70 and the second oil return hole 70 in the accumulator 40 may be used. There is a problem that an oil level is formed between the oil return hole 71 and the oil return hole 71. When the two-layer separation between the liquid refrigerant and the oil occurs, the oil having a low specific gravity floats on the liquid refrigerant, so that the liquid refrigerant is sucked from the first oil return hole 70. That is, oil cannot be sucked from the first oil return hole 70 when the gas refrigerant flows through the U-shaped pipe 52, so that there is a problem that the amount of oil returned to the compressor 1 is reduced.

  With respect to such a problem, in Patent Document 2 (Japanese Patent Laid-Open No. 10-205931), an oil return hole 9 provided in a pipe wall of the outlet pipe 7 located near the bottom of the accumulator, and an opening side pipe of the outlet pipe 7 By providing at least one or more auxiliary oil return holes 10 provided in the vertical direction on the wall, the amount of oil returned to the compressor can be ensured regardless of whether or not liquid refrigerant accumulates in the storage chamber 5. It is said.

  Further, in Patent Document 3 (Japanese Patent No. 3163312), when two accumulators are connected in series, the refrigerant pressure loss increases, and the problem that the refrigerating capacity cannot be fully exhibited is solved in one pressure vessel. A partition plate 21 is provided to divide the first chamber 22 corresponding to the first accumulator and the second chamber 23 corresponding to the second accumulator, and the two plates communicate with each other on the upper side of the partition plate 21. The hole 28 is provided, the refrigerant inflow pipe 24 into which the refrigerant flows into the first chamber 22 is provided, the refrigerant outflow pipe 24 through which the refrigerant flows out into the first chamber 22 or the second chamber 23 is provided, It is disclosed that an oil inflow pipe 26 connected to the oil separator 2 and an oil outflow pipe 27 connected to the compressor 1 are provided in the chamber 23.

JP 2010-203733 A Japanese Patent Laid-Open No. 10-205931 Japanese Patent No. 3163312

  According to the prior art of Patent Document 1, when the two-layer separation between the liquid refrigerant and the oil occurs in the accumulator as described above, the oil floats on the liquid refrigerant and the oil return hole provided below is provided. There was a problem that the oil return from did not always work.

  Even if the accumulator outlet pipe is provided with a plurality of auxiliary oil return holes as in Patent Document 2, the amount of liquid refrigerant in the accumulator varies, so it is not necessarily at the position of the auxiliary oil return hole provided in the upper part. There is not always an oil layer, and there is a possibility that a predetermined amount of oil return to the compressor cannot be secured.

  In addition, when the liquid level is low, oil is sucked from the upper oil return hole together with the gas refrigerant from above the U-shaped pipe. Since the liquid refrigerant is sucked from the plurality of lower auxiliary oil return holes and the oil return holes at the same time as the oil is sucked from the upper auxiliary oil return hole together with the gas refrigerant, the flow rate ratio of the oil to the refrigerant is lowered. As described above, there is a problem that it is difficult to secure a necessary oil flow rate as a result.

  In the prior art disclosed in Patent Document 3, since the oil is taken out from the bottom of the accumulator, the oil cannot be stored inside the accumulator, and all of the oil that has flowed to the accumulator flows into the refrigeration cycle. Can not return. If a large amount of oil flows in the refrigeration cycle, for example, there is a problem that loss in a heat exchanger or the like increases.

  Therefore, the present invention solves these problems, and even when the refrigerant and refrigeration oil enclosed in the refrigeration cycle are configured with physical properties such that two-layer separation occurs in the actual use temperature range, The purpose is to improve the reliability of the compressor and to save energy by supplying an appropriate amount of oil to the compressor.

In order to solve the above problems, for example, the configuration described in the claims is adopted.
The present application includes a plurality of means for solving the above problems.
“The refrigerant and the refrigerating machine oil enclosed in the refrigeration cycle are configured with physical properties such that the low-temperature two-layer separation temperature exceeds −20 ° C. in an oil concentration range of 20 to 50% with respect to the refrigerant. An oil inflow pipe into which oil separated by the oil separator flows, a refrigerant inflow pipe into which refrigerant flows, an oil storage section for storing oil flowing in from the oil inflow pipe, and a refrigerant inflow pipe separately from the oil storage section A liquid refrigerant reservoir that stores the liquid refrigerant that flows in, an opening that sucks oil stored at the bottom of the oil reservoir, an oil return pipe that allows oil to flow upward, and a reservoir at the bottom of the liquid refrigerant reservoir A refrigerant return pipe that has an opening for sucking in the liquid refrigerant and flows the liquid refrigerant upward, and joins the refrigerant return pipe and the oil return pipe, and the refrigerant from the refrigerant inflow pipe passes through the refrigerant return pipe or oil. An air conditioner characterized by flowing through a return pipe.

  According to the present invention, even when the refrigerant and the refrigerating machine oil enclosed in the refrigeration cycle have physical properties that cause two-layer separation in the actual use temperature range, an appropriate amount of oil is obtained by the accumulator. By supplying to the compressor, it becomes possible to improve the reliability of the compressor and to save energy.

It is the low temperature side two-layer separation characteristic of the combination of the refrigerant | coolant and refrigerating machine oil in Example 1. FIG. It is a block diagram of the refrigerating cycle which shows the structure of the air conditioning apparatus in Example 1. FIG. 3 is an internal structure diagram of an accumulator 40 in Embodiment 1. FIG. It is an internal structure figure of the accumulator 40 in Example 2. FIG. It is an internal structure figure of the accumulator 40 in Example 3. FIG. It is an internal structure figure of the accumulator 40 in Example 4. FIG. It is an internal structure figure of the accumulator 40 in Example 5. FIG. It is a block diagram of the refrigerating cycle which shows the structure of the air conditioning apparatus in Example 6. FIG. It is a block diagram of the refrigerating cycle which shows the structure of the air conditioning apparatus in Example 6. FIG. It is a figure explaining the refrigerating cycle at the time of air_conditionaing | cooling operation of the conventional air conditioning apparatus. It is an internal structure figure of the conventional accumulator.

  The air conditioner according to the embodiment of the present invention will be described in detail below with reference to FIGS.

A first embodiment of the present invention will be described with reference to FIGS.
FIG. 1 shows the relationship between the refrigerant and refrigerant oil concentrations and the two-layer separation temperature. The combination of the same HFC refrigerant R410A (HFC32: 50%, R125: 50%) and ether oil has a low low temperature side two-layer separation temperature of −50 ° C., which is a temperature zone used as an air conditioner −20 Two-layer separation does not occur at ℃. On the other hand, in the combination of HFC32 and ester oil, the two-layer separation temperature is as high as −1 ° C. in the oil concentration range of 20 to 50%. Will occur. The oil concentration is defined as Q _oil / (Q _liq + Q _oil ) [kg] when the liquid refrigerant amount is Q _liq [kg] and the oil amount is Q _oil [kg]. It depends on each physical property.

  Here, in this embodiment, an ester oil that is compatible with HFC32 is employed. However, since this ester oil has an oil concentration in the range of 20 to 50% as described above and the low temperature side two-layer separation temperature exceeds −20 ° C., when used in a refrigeration cycle in combination with the R32 refrigerant as described above, Two-layer separation may occur in the operating temperature range. On the other hand, according to the structure of the accumulator of this embodiment, even in such a case, an object is to improve the reliability of the compressor by supplying an appropriate amount of oil to the compressor.

  In the following, a case where 70% by weight or more of R32 refrigerant is employed as the refrigerant sealed in the refrigeration cycle and ester oil is employed as the refrigerating machine oil will be described, but the present invention is limited to this. is not. That is, the refrigerant and the refrigerating machine oil enclosed in the refrigeration cycle are configured with physical properties that the low-temperature two-layer separation temperature may exceed or exceed −20 ° C. when the oil concentration with respect to the refrigerant is in the range of 20 to 50%. The same effect can be obtained with such a combination of refrigerant and refrigerating machine oil.

  FIG. 2 is a configuration diagram of the refrigeration cycle showing the configuration of the air conditioner in the present embodiment. Also in this embodiment, as in FIG. 10, the outdoor unit 30 and the indoor unit 31 are connected by the liquid pipe 13 and the gas pipe 12, and the compressor 1 that compresses the refrigerant, and the oil compressed from the refrigerant compressed by the compressor 1 And an accumulator 40 disposed on the suction side of the compressor 1.

  Description of other contents similar to those in FIG. 10 is omitted, but in FIG. 1, the bypass circuit 24 through which the oil separated by the oil separator 5 passes and the inlet pipe 25 through which the refrigerant returning from the refrigeration cycle passes are merged. 10 is different from the configuration of FIG. 10 in that the bypass circuit 24 is directly connected to the oil inflow pipe 26 in the accumulator 40 and the inlet pipe 25 is directly connected to the refrigerant inflow pipe 27. In this embodiment, an example in which two indoor units 31 are connected in parallel is shown, but one or more indoor units 31 may be connected.

  FIG. 3 is an internal structural diagram of the accumulator 40 in this embodiment. In this embodiment, a small tank 80 having a diameter smaller than that of the accumulator 40 and having an opening at the top is installed inside the container of the accumulator 40, and the bottom of the tank 80 is used as an oil storage portion 81. The oil 60 separated by the oil separator 5 flows from the oil inflow pipe 26 and is stored in the oil storage portion 81.

  On the other hand, the refrigerant returning from the refrigeration cycle flows from the refrigerant inflow pipe 27, and after the gas refrigerant and the liquid refrigerant are separated from each other, the liquid refrigerant 61 is stored in the liquid refrigerant storage section 82 at the bottom of the accumulator 40. . That is, in the present embodiment, two reservoirs, that is, an oil reservoir 81 and a liquid refrigerant reservoir 82 different from the oil reservoir 81 are formed inside the accumulator 40, and their upper spaces communicate with each other. It is. The oil inflow pipe 26 is opened so as to be discharged into the oil storage section 81 and the refrigerant inflow pipe 27 is discharged into the liquid refrigerant storage section 82, so that oil and refrigerant flowing in from the respective pipes are not mixed. It is the structure stored by each storage part.

  The U-shaped refrigerant return pipe 52 sucks the gas refrigerant flowing in from the refrigerant inflow pipe 27 from the inflow portion 55 formed at the upper end, and is configured to go from the inflow portion 55 to the bottom of the liquid refrigerant storage portion 82. Is done. The refrigerant return pipe 52 is bent in a U shape at the bottom of the liquid refrigerant reservoir 82 and faces upward, and the other end is connected to the suction pipe 22 at the top of the accumulator 40. The refrigerant return pipe 52 is provided with a pressure equalizing hole 76 in the vicinity of the connection port with the suction pipe 22.

  A liquid refrigerant return hole 74 (opening) for sucking the liquid refrigerant stored at the bottom of the liquid refrigerant reservoir 82 is formed at the lower part of the refrigerant return pipe 52, and the liquid refrigerant return hole 74 (opening) sucks the liquid refrigerant. The liquid refrigerant 61 is flowed upward. As a result, the liquid refrigerant 61 sucked from the liquid refrigerant return hole 74 (opening) flows out to the suction pipe 22 together with the gas refrigerant passing through the refrigerant return pipe 52.

  Further, the refrigerant return pipe 52 is higher than the liquid refrigerant return hole 74, and the liquid refrigerant return hole 75 is formed at the discharge side position of the refrigerant return pipe 52. When the amount of the liquid refrigerant 61 stored therein increases. The flow rate of the liquid refrigerant 61 returning to the compressor 1 is increased.

  On the other hand, an oil return hole 72 (opening) for sucking the oil stored in the bottom of the oil storage part 81 is provided, and an oil return pipe 53 through which the oil flows upward is arranged. The oil return hole 72 (opening) is configured to open downward at the bottom of the oil reservoir 81. The other end of the oil return pipe 53 is connected to the refrigerant return pipe 52 at the connecting portion 54 so that the flow paths of the oil return pipe 53 and the refrigerant return pipe 52 are joined.

  Next, the operation in the accumulator 40 will be described. The gas refrigerant evaporated in the refrigeration cycle flows into the accumulator 40 from the refrigerant inflow pipe 27 and is sucked from an inflow portion 55 formed at the upper end of the refrigerant return pipe 52, and from the refrigerant return pipe 52 to the suction pipe 22 of the compressor 1. Spill into. At this time, the gas refrigerant flows through the refrigerant return pipe 52, thereby causing a pressure loss, and the pressure in the refrigerant return pipe 52 is reduced. As a result, a differential pressure is generated between the internal space of the accumulator 40 and the connection portion 54, so that the oil stored in the oil storage portion 81 according to this differential pressure passes through the oil return pipe 53 and enters the refrigerant return pipe 52. And leaked. Therefore, since oil flows into the compressor 1 through the suction pipe 22 together with the refrigerant, oil can be supplied to the compressor 1 by this action.

  As described above, in this embodiment, in the accumulator 40, the oil 60 and the liquid refrigerant 61 are divided into the oil storage part 81 and the liquid refrigerant storage part 82 and stored separately. Since it is structured to be sucked into the pipe 52 in accordance with the flow rate of the gas refrigerant, it is possible to supply oil from the oil return pipe 53 even when the liquid refrigerant 61 is accumulated. Reliability can be improved.

  Further, one part of the oil that flows out during the refrigeration cycle without being separated by the oil separator 5 flows into the accumulator 40 from the refrigerant inflow pipe 27, and is stored in the liquid refrigerant storage unit 82. Even in such a case, in the present embodiment, since the refrigerant is taken into the refrigerant return pipe 52 through the liquid refrigerant return hole 74 and sucked into the compressor 1, it is possible to prevent the oil from returning. Thus, since the function which discharges the oil which accumulates in the liquid refrigerant storage part 82 is also provided, it can prevent that oil becomes insufficient, and can provide a reliable air conditioning apparatus.

  Here, in this embodiment, the oil flows upward through the oil return pipe 53 and the height of the connecting portion 54 is higher than the upper end of the oil storage portion 81. Therefore, when the air conditioner is stopped, The oil inside the return pipe 53 returns to the oil reservoir 81 by gravity. Therefore, the oil is not supplied to the compressor 1 in this case. In addition, the upper end of the oil storage part 81 shows the height position where the upper end of the wall surface of the small tank 80 or the upper opening part of a small tank is formed.

  On the other hand, when the connection part 54 is disposed at a position lower than the upper end of the oil storage part 81, the connection is made when the operation is stopped when the oil level of the oil storage part 81 is higher than the connection part 54. The oil 60 flows out to the refrigerant return pipe 52 side through the oil return pipe 53 until the oil level height of the part 54 and the oil storage part 81 becomes the same, and then the liquid refrigerant return hole provided at the bottom of the refrigerant return pipe 52 It flows out from 74 into the liquid refrigerant storage part 82. In this case, a large amount of oil will be mixed with the refrigerant, and if two-phase separation occurs in this state, the oil may float and not return from the liquid refrigerant return hole 74, which impairs reliability due to lack of oil. There was a possibility.

  Therefore, in this embodiment, since the position of the connection portion 54 is arranged at a position higher than the upper end of the oil storage portion 81, the oil 60 is reliably stored separately from the liquid refrigerant 61 in the oil storage portion 81 in the accumulator 40. And two-phase separation can be avoided. Therefore, since it becomes possible to ensure the oil supply to the compressor 1, the reliability of an air conditioning apparatus can be improved.

  The amount of oil supplied to the compressor 1 is determined by the refrigerant-side pressure loss from the inflow portion 55 to the connection portion 54 of the refrigerant return pipe 52, in other words, is determined according to the flow rate of the refrigerant. Since the amount of oil required for the compressor 1 has a correlation with the flow rate of the refrigerant, it is possible to prevent excessive oil supply to the compressor 1 by this action, so that the efficiency of the compressor 1 can be kept high. It is possible to provide an air conditioner with high energy savings.

  In general, the inlet 55 of the refrigerant return pipe 52 is opened to have the same inner diameter or cross-sectional area as the refrigerant return pipe 52 so that the refrigerant pressure loss does not increase excessively. A large amount of the liquid refrigerant 61 is sucked when it reaches a position higher than the inflow portion 55. If this situation occurs, the reliability of the compressor 1 may be affected. Therefore, the height of the inflow portion 55 of the refrigerant return pipe 52 is designed so as not to suck the liquid refrigerant 61.

  Therefore, in the present embodiment, the upper end of the oil storage part 81 constituted by the small tank 80 is arranged to be higher than the inflow part 55 at the upper end of the refrigerant return pipe 52 on the suction side. Thereby, it is possible to prevent the liquid refrigerant from flowing into the oil storage part beyond the wall surface of the oil storage part 81 configured by the small tank 80. Therefore, since it is possible to prevent the refrigerant and oil from mixing, the problem of two-phase separation can be avoided, and a highly reliable air conditioner can be provided.

  Moreover, when the quantity of the oil 60 stored in the oil storage part 81 which stores excess oil increases, there exists a possibility that the oil holding amount in the compressor 1 may be reducing. Therefore, the oil return pipe 53 of the present embodiment is formed with an oil return hole 73 at a position higher than the oil return hole 72 (opening portion) and lower than the upper end of the oil storage portion 81 constituted by the small tank 80. It is said. Thereby, since the return amount of the oil 60 can be increased and the oil supply amount to the compressor 1 can be increased, the reliability of the compressor 1 can be improved.

  In the present embodiment, the inner diameter or area of the oil return hole 73 formed in the upper part is made larger than the inner diameter or area of the oil return hole 72 (opening). In the following examples, the area of the hole indicates the surface area on which the oil return hole 73 is formed if it is formed on the surface of the pipe like the oil return hole 73 in FIG. If it is formed by opening the end of the pipe as in 72, the cross-sectional area of the pipe in the oil return hole 72 is shown.

  Thereby, when the amount of the oil 60 increases to the position of the oil return hole 73, the return amount of the oil 60 can be greatly increased, so that the reliability of the compressor 1 can be further improved. Even if the oil return amount is increased by the oil return hole 73, when it is necessary to return the oil to the compressor 1, the liquid refrigerant overflows from the small tank 80 and flows out to the liquid refrigerant reservoir 82. By returning the oil together with the liquid refrigerant 61 from the return hole 74, the amount of oil supply can be further increased.

  By the way, when the refrigerant returning from the refrigeration cycle is in a two-phase state in which gas refrigerant and liquid refrigerant are mixed, the refrigerant flowing from the refrigerant inflow pipe 27 is separated into gas and liquid, and the gas refrigerant is sucked from the inflow portion 55 of the refrigerant return pipe 52. The liquid refrigerant 61 is stored at the bottom of the liquid refrigerant storage section 82 toward the pipe 22. The liquid refrigerant 61 is mixed with the gas refrigerant from the liquid refrigerant return hole 74 near the lower end of the refrigerant return pipe 52 so that the large amount of liquid refrigerant 61 does not return to the compressor 1 from the accumulator 40 at a time. Returned to 1.

  The flow rate of the liquid refrigerant is determined according to the pressure difference between the inside and the outside of the refrigerant return pipe 52 caused by the refrigerant pressure loss from the inflow portion 55 of the refrigerant return pipe 52 to the liquid refrigerant return hole 74. In the present embodiment, since the liquid refrigerant can be gradually returned to the compressor 1 by the refrigerant return pipe 52, not only can a large amount of liquid refrigerant be returned at a time, but also the inside of the accumulator 40 can be positively returned. The liquid refrigerant can be reduced at an early stage.

  By the way, although the oil return amount to the compressor 1 by the oil return pipe 53 is determined by the flow rate of the refrigerant flowing in the refrigerant return pipe 52 as described above, the difference in height from the oil level of the oil storage part 81 to the connection part 54 is determined. In other words, there is a restriction that the refrigerant pressure loss in the refrigerant return pipe 52 must be larger than the influence of gravity caused by the above, that is, the head difference. In order to improve the energy saving property of the air conditioner, it is desirable that the refrigerant pressure loss is small.

  Therefore, in the present embodiment, the bottom surface of the oil storage unit 81 configured by the small tank 80 is arranged at a position higher than the bottom surface of the liquid refrigerant storage unit 82. Thereby, the difference in the oil head required for supplying a predetermined amount of oil is reduced, and the refrigerant pressure loss in the refrigerant return pipe 52 can be reduced, so that an air conditioner with high energy saving can be provided.

  In this embodiment, the refrigerant return pipe 52 is configured such that the inner diameter or area of the upper liquid refrigerant return hole 75 is larger than the inner diameter or area of the liquid refrigerant return hole 74 at the bottom of the liquid refrigerant reservoir 82. . Thereby, since the liquid level of the liquid refrigerant is less likely to be higher than the upper liquid refrigerant return hole 75, the liquid refrigerant and the oil are mixed in the liquid refrigerant storage portion 82, and the oil floats upward when the oil floats upward. Therefore, the oil can be returned to the compressor 1 through the liquid refrigerant return hole 75, and the reliability can be improved.

A second embodiment of the present invention will be described with reference to FIG. Description of the same points as in the first embodiment will be omitted.
FIG. 4 is an internal structural diagram of the accumulator 40 in the present embodiment. As shown in FIG. 4, the oil return pipe 53 of this embodiment is directed upward from the bottom of the oil reservoir 81 and returns to the refrigerant via the wall surface of the small tank 80 at a position lower than the upper end of the oil reservoir 81. It is configured to go to the tube 52. As a result, in the first embodiment, the oil return pipe 53 is configured to go from the oil storage portion 81 toward the refrigerant return pipe 52 from a position higher than the upper end of the oil storage portion 81. According to this, the height difference between the oil level of the oil reservoir 81 and the connecting portion 54 can be reduced.

  Therefore, the refrigerant pressure loss of the refrigerant return pipe 52 required for flowing a predetermined amount of oil from the oil return pipe 53 to the refrigerant return pipe 52 can be reduced. Therefore, since an appropriate amount of oil can be returned to the compressor 1 while reducing the refrigerant pressure loss of the refrigerant return pipe 52, it is possible to provide a highly reliable air conditioner while saving energy.

  In the present embodiment, the height of the connecting portion between the oil return pipe 53 and the small tank 80 from the oil return hole 72 (opening) of the oil return pipe 53 is the oil return hole of the oil return pipe 53 in the first embodiment. This corresponds to the height from 72 (opening) to the oil return hole 73. The principle that oil in the oil reservoir 81 flows into the refrigerant return pipe 52 from the oil return hole 72 (opening) is the same as that in the first embodiment, but in this embodiment, the oil level is higher than that of the connecting portion 54. If it becomes higher, oil flows out to the refrigerant return pipe 52 side due to the head difference.

  Therefore, when the oil storage amount increases, the oil supply amount to the compressor 1 can be increased using the head difference, and therefore the upper oil return hole 73 that is necessary in the first embodiment is not necessary. it can.

A third embodiment of the present invention will be described with reference to FIG. Description of the same points as in the first embodiment will be omitted.
FIG. 5 is an internal structural diagram of the accumulator 40 in this embodiment.
In this embodiment, the oil return pipe 53 is formed in a substantially U shape, and the gas refrigerant flowing in from the refrigerant inflow pipe 27 is sucked from the inflow portion 77 formed at the upper end of the oil return pipe 53, and the oil return pipe 53. To the suction pipe 22 of the compressor 1. That is, the oil return pipe 53 is configured to be bent downward from the suction side inflow part 77 in a U shape at the bottom of the oil storage part 81 and to be connected to the suction pipe 22 upward.

  At this time, the gas refrigerant flows through the oil return pipe 53 to cause a pressure loss, and the pressure in the oil return pipe 53 decreases. As a result, a pressure difference between the inside and the outside of the oil return hole 72 (opening) formed in the bottom of the oil return pipe 53 is generated, so that the oil stored in the oil storage portion 81 is oiled according to this differential pressure. It flows out to the suction pipe 22 through the return pipe 53. Therefore, since oil flows into the compressor 1 through the suction pipe 22 together with the refrigerant, oil can be supplied to the compressor 1 by this action. Further, since the refrigerant return pipe 52 does not flow a gas refrigerant in this embodiment, the cross-sectional area of the oil return pipe 53 is larger than the cross-sectional area of the refrigerant return pipe 52.

  According to the configuration of the present embodiment, since the gas refrigerant flows through the oil return pipe 53 that is shorter than the refrigerant return pipe 52 of the first and second embodiments, the oil is returned to the compressor 1. Compared to the above, the pressure loss in the oil return pipe 53 can be reduced, and an air conditioner with improved energy saving can be provided.

  An oil return hole 73 is formed in the oil return pipe 53 at a position higher than the oil return hole 72 (opening portion) and lower than the upper end of the oil storage portion 81 configured by the small tank 80. Thereby, since the return amount of the oil 60 can be increased and the oil supply amount to the compressor 1 can be increased, the reliability of the compressor 1 can be improved.

  On the other hand, the refrigerant return pipe 52 has a liquid refrigerant return hole 74 (opening) for sucking in the liquid refrigerant stored at the bottom of the liquid refrigerant storage portion 82, and the liquid refrigerant return hole 74 (opening) causes liquid to rise upward. A refrigerant flows. In FIG. 5, the liquid refrigerant return hole 74 (opening portion) of the refrigerant return pipe 52 is configured to open downward at the bottom of the liquid refrigerant storage portion 82. The other end of the liquid refrigerant return hole 74 (opening) is connected to the refrigerant return pipe 52 and the oil return pipe 53 by a connection portion 54 provided at a position higher than the oil level in the oil storage portion 81. The flow paths are merged.

  As a result, the liquid refrigerant return hole 74 of the refrigerant return pipe 52 can be positioned close to the bottom surface of the accumulator 40. Therefore, even if there is oil that is stored on the bottom surface and cannot be sucked in the case of a U-shaped pipe, this embodiment is carried out. The liquid refrigerant return hole 74 (opening) in the example can be inhalable.

A fourth embodiment of the present invention will be described with reference to FIG. Description of the same points as in the third embodiment will be omitted.
FIG. 6 is an internal structure diagram of the accumulator 40 in this embodiment. In this embodiment, the configuration of the refrigerant return pipe 52 is different from that of the third embodiment, and the same structure as that of the first embodiment is used. Since the configuration of the oil return pipe 54 is the same as that of the third embodiment, detailed description thereof is omitted.

  The refrigerant return pipe 52 of the present embodiment is formed in a substantially U shape, and the gas refrigerant flowing from the refrigerant inflow pipe 27 is sucked from an inflow portion 55 formed at the upper end of the refrigerant return pipe 52. Further, the refrigerant return pipe 52 is configured to be directed downward from the inflow portion 55 on the suction side, bent in a U shape at the bottom of the liquid refrigerant storage portion 82, and directed upward. The flow path is merged by connecting the refrigerant return pipe 52 and the oil return pipe 53 at the connection part 54 provided at a position higher than the oil level in the oil storage part 81.

  Therefore, in this embodiment, the gas refrigerant flows in from both the inflow portion 77 of the oil return pipe 54 and the inflow portion 55 of the refrigerant return pipe 52 and flows toward the suction pipe 22. Oil is sucked from the oil return hole 72 (or oil return hole 73), and liquid refrigerant is sucked from the liquid refrigerant return hole 74 (or liquid refrigerant return hole 75) in the refrigerant return pipe 52. As a result, gas refrigerant flows and oil and liquid refrigerant can be supplied to the compressor 1.

  According to the configuration of the third embodiment shown in FIG. 5, oil and liquid refrigerant can be similarly supplied to the compressor 1 by flowing the gas refrigerant through the oil return pipe 54, but the head difference of the refrigerant return pipe 52 is different. Therefore, in order to return the liquid refrigerant 61 to the refrigeration cycle so that the liquid refrigerant 61 does not accumulate in the accumulator 40, a pressure loss is caused when the gas refrigerant flows through the oil return pipe 54 so as to be larger than the head difference of the refrigerant return pipe 52. In addition, it was necessary to greatly reduce the pressure of the connecting portion 43.

  Therefore, in this embodiment, with the above-described configuration, the liquid refrigerant return hole 74 (or liquid refrigerant) can be obtained by allowing the gas refrigerant to flow through the refrigerant return pipe 52 without reducing the pressure at the connection portion 54 as shown in FIG. Since the liquid refrigerant can be sucked from the return hole 75), the pressure loss can be reduced as compared with the third embodiment, and further energy saving can be achieved.

  In this embodiment, the oil storage unit 81 and the liquid refrigerant storage unit 82 are separated using the small tank 80. However, the present invention is not limited to this, and a partition plate is provided at the bottom of the accumulator 40. The storage portions may be formed on one side and the other side of the partition plate. The oil return pipe 53 and the refrigerant return pipe 52 do not necessarily need to be connected inside the accumulator 40, and may be connected outside the accumulator 40 as long as the oil level is higher than the oil level of the oil reservoir 81.

A fifth embodiment of the present invention will be described with reference to FIG. Description of the same points as in the fourth embodiment will be omitted.
FIG. 7 is an internal structure diagram of the accumulator 40 in the present embodiment. In the present embodiment, the oil return pipe 53 and the refrigerant return pipe 52 are U-shaped and connected in series.

  First, the refrigerant return pipe 52 is formed in a substantially U shape, and the refrigerant return pipe 52 is configured to go to the bottom of the liquid refrigerant storage part 82 after the gas refrigerant flows in from the inflow part 55 formed at the upper end. Is done. The refrigerant return pipe 52 is formed with a liquid refrigerant return hole 74 at the bottom of the liquid refrigerant reservoir 82 and is bent into a U-shape, and sucks the liquid refrigerant in the liquid refrigerant return hole 74 and then moves upward. It is configured.

  The oil return pipe 53 is configured to be connected to the refrigerant return pipe 52 at the upper connection portion 54, and the oil return pipe 53 is configured to go from the connection portion 54 to the bottom of the oil storage portion 81. Here, the oil return pipe 53 and the refrigerant return pipe 52 are separated and further called a connecting portion 54, but these may be integrally formed.

  The oil return pipe 53 is formed with an oil return hole 72 at the bottom of the oil reservoir 81 and bent into a U shape. After the oil is sucked in the oil return hole 72, the oil return pipe 53 is connected to the suction pipe 22 upward. Is configured to do.

  Also in this embodiment, since the connecting portion 54 is arranged at a position higher than the oil level of the oil storing portion 81, the oil and the liquid refrigerant can be reliably stored separately. In addition, the oil return pipe disposed in the oil reservoir 81 disposed at a high position is configured to be on the downstream side. The refrigerant pressure loss in the piping tends to increase when the oil mixing ratio is high. Therefore, an increase in the refrigerant pressure loss can be suppressed by arranging an oil return pipe with a high oil mixing ratio on the downstream side.

  In addition, the connection in series can reduce the number of brazing parts for piping, which facilitates production and improves reliability.

A sixth embodiment of the present invention will be described with reference to FIG.
FIG. 8 is a configuration diagram of a refrigeration cycle showing the configuration of the air conditioner in the present embodiment. In this embodiment, the accumulator is composed of two liquid refrigerant quantity tanks 41 and an oil tank 42. The inlet pipe 25 through which the refrigerant from the refrigeration cycle flows is connected to the liquid refrigerant tank 41, and the bypass circuit 24 through which the oil from the oil separator 5 flows is connected to the oil tank 42. Inside the liquid refrigerant tank 41, there is disposed a liquid return pipe 52 that opens upward and is bent in a U shape near the bottom. A liquid return hole is formed in the vicinity of the U shape of the liquid return pipe 52. 74 is arranged.

  The oil tank is provided with an oil return pipe 53 that opens upward and is bent in a U shape near the bottom, and an oil return hole 71 is formed in the pipe near the bottom. The oil tank 42 and the liquid refrigerant tank 41 are connected to each other by a communication pipe 29 that communicates the vicinity of the upper end of each tank. The gas refrigerant and the liquid refrigerant returning from the refrigeration cycle are gas-liquid separated inside the liquid refrigerant tank 41, and the liquid refrigerant flows out to the suction pipe 22 of the compressor 1 together with the gas refrigerant flowing inside the liquid return pipe 52.

On the other hand, the oil returning from the oil separator 5 flows into the oil tank 42. The refrigerant flows into the oil tank 42 from the communication pipe 29 opened near the upper end of the liquid refrigerant tank 41, but only the gas refrigerant separated in the liquid refrigerant tank 41 flows into the oil tank 42. And liquid refrigerant are prevented from mixing. The oil flows out of the oil tank 42 through the oil return pipe 53 together with the gas refrigerant flowing in from the liquid refrigerant tank 41, and at a position higher than the oil level in the oil tank 42, the liquid refrigerant tank It merges with the refrigerant flowing out of 41.
Therefore, the oil stored in the oil tank including when the operation is stopped and the liquid refrigerant stored in the liquid refrigerant tank are not mixed, and the air conditioner is highly reliable and energy saving. Can be provided.

A seventh embodiment of the present invention will be described with reference to FIG.
FIG. 9 is a configuration diagram of the refrigeration cycle showing the configuration of the air conditioner in the present embodiment. In the present embodiment, a cycle system diagram of the embodiment when applied to an air conditioner of a system in which two outdoor units 90 are connected in parallel to function as one outdoor unit is shown.
When multiple outdoor units are connected in parallel, the refrigerant returned from the cycle may return to one of the outdoor units, and in such a case, oil shortage occurs in the other outdoor unit. There were sexual challenges. As shown in the prior art 1 for such a problem, a technique is known in which a first oil return hole and a second oil return hole are provided in the accumulator 40.

  In Examples 1 to 6, since the first oil return hole 72 is provided near the lower end of the oil return pipe and the second oil return hole 73 is provided above the first oil return pipe, when the oil amount increases Since the amount of oil supplied to the compressor 1 can be increased and the amount of oil spilled into the cycle can be increased, it is possible to finally correct the non-uniformity in the amount of oil retained between the outdoor units. ing. Therefore, even when applied to a system having such a cycle configuration, a highly reliable air conditioner can be provided.

  DESCRIPTION OF SYMBOLS 1 ... Compressor, 5 ... Oil separator, 26 ... Oil inflow pipe, 27 ... Refrigerant inflow pipe, 40 ... Accumulator, 52 ... Refrigerant return pipe, 53 ... Oil return pipe, 55 ... Upper end of suction side of refrigerant return pipe, 72, 73 ... oil return hole, 74, 75 ... liquid refrigerant return hole, 81 ... oil reservoir, 82 ... liquid refrigerant reservoir.

Claims (7)

A compressor for compressing the refrigerant;
An oil separator for separating oil from the refrigerant compressed by the compressor;
In an air conditioner comprising an accumulator disposed on the suction side of the compressor,
The refrigerant and the refrigeration oil enclosed in the refrigeration cycle are configured with physical properties such that the low-temperature two-layer separation temperature exceeds −20 ° C. in an oil concentration range of 20 to 50% with respect to the refrigerant,
The accumulator is
An oil inflow pipe into which oil separated by the oil separator flows;
A refrigerant inflow pipe into which refrigerant flows,
An oil reservoir for storing oil flowing in from the oil inflow pipe;
Separately from the oil reservoir, a liquid refrigerant reservoir that stores liquid refrigerant flowing from the refrigerant inlet pipe,
An oil return pipe having an opening for sucking oil stored in the bottom of the oil storage section, and flowing oil upward;
A refrigerant return pipe having an opening for sucking the liquid refrigerant stored in the bottom of the liquid refrigerant storage section and flowing the liquid refrigerant upward;
The air conditioner characterized in that the refrigerant return pipe and the oil return pipe are merged, and the refrigerant from the refrigerant inflow pipe flows through the refrigerant return pipe or the oil return pipe. In the air conditioning apparatus according to claim 1,
The air conditioner characterized in that the oil return pipe and the refrigerant return pipe are merged at a position higher than the upper end of the oil reservoir. In the air conditioning apparatus according to claim 1,
The air conditioner is characterized in that the upper end of the oil reservoir is positioned higher than the upper end of the refrigerant return pipe on the suction side. In the air conditioning apparatus according to claim 1,
The opening of the oil return pipe is formed as a first oil return hole formed at the bottom of the oil reservoir,
The oil return pipe is higher than the first oil return hole, and a second oil return hole is formed at a position lower than the upper end of the oil reservoir,
The air conditioner characterized in that an area of the second oil return hole is larger than an area of the first oil return hole. In the air conditioning apparatus according to claim 1,
The air conditioning apparatus according to claim 1, wherein a bottom surface of the oil reservoir is disposed at a position higher than a bottom surface of the liquid refrigerant reservoir. In the air conditioning apparatus according to claim 1,
The opening of the refrigerant return pipe is formed as a first liquid refrigerant return hole formed at the bottom of the liquid refrigerant reservoir,
The refrigerant return pipe is higher than the first liquid refrigerant return hole, and a second liquid refrigerant return hole is formed at a discharge side position of the refrigerant return pipe;
An air conditioner characterized in that an area of the second liquid refrigerant return hole is larger than an area of the first liquid refrigerant return hole. In the air conditioning apparatus according to claim 1,
An air conditioner characterized in that 70% by weight or more of the refrigerant sealed in the refrigeration cycle is R32, and ester oil is used as the refrigerating machine oil.