JP5975706B2 - Accumulator and refrigeration cycle apparatus - Google Patents

Description

  The present invention relates to an accumulator used in a refrigeration cycle apparatus.

  For example, there is a refrigeration cycle apparatus in which a refrigerant circuit is configured by sequentially connecting a plurality of compressors, condensers, expansion valves, evaporators, and accumulators connected in parallel. In the refrigeration cycle apparatus, for example, refrigeration oil is used to smoothly drive the compression mechanism in the compressor. The refrigerating machine oil circulates in the refrigerant circuit together with the refrigerant.

  Here, in the refrigerant flowing through the refrigerant circuit, a liquid back that returns to the compressor suction side (low pressure side) occurs due to an increase in liquid refrigerant (liquid refrigerant). At this time, since the refrigerant flowing into the compressor increases as compared with the refrigerating machine oil, the concentration of the refrigerating machine oil decreases. When the concentration of the refrigerating machine oil is reduced, the compression mechanism is damaged. Therefore, there is a refrigerating apparatus (refrigeration cycle apparatus) that can ensure the concentration of refrigerating machine oil in a plurality of compressors even during liquid back (for example, Patent Document 1).

  In such a refrigerating apparatus, the refrigerating machine oil is compatible with the refrigerant, and an oil recovery unit that recovers excess refrigerating machine oil in the compressor is provided in the accumulator, and the refrigerating machine oil is held in the accumulator. Even when a large amount of liquid back occurs due to abnormality in the refrigerant circuit, such as a defective expansion valve, and the accumulator overflows with liquid refrigerant, a plurality of compressors are a mixture of oil and refrigerant in the accumulator. Supplied. Accordingly, liquid refrigerant having a certain oil concentration flows into a plurality of compressors, so that the oil concentration in the compressor is kept above a certain value even if a liquid back state continuously occurs. be able to.

  In addition, for example, when two or more compressors are provided, it is possible to reduce the bias toward one of the compressors during liquid back when the refrigerant is circulated with a low refrigerant circulation amount such as low humidity and low frequency. Therefore, a liquid return hole is provided in the lowermost part of the U-shaped tube (refrigerant outflow piping) of the accumulator. And when the liquid is backed up with a low refrigerant circulation rate due to low wetness, low frequency, etc., the liquid level should not be raised to the U-shaped pipe (refrigerant outlet pipe) inlet (the liquid will not return from the U-shaped pipe inlet) In other words, the liquid is returned only from the liquid return hole. For example, when there is no liquid return hole and there is a difference in the height of the U-shaped pipe (refrigerant outflow pipe) suction port, the liquid backed compressor is biased depending on the height. Here, even if there is a liquid return hole, it is possible that the liquid back will be biased due to the difference in the height of the liquid return hole, but in the case of a liquid back with a lower circulation rate than when there is no liquid return hole Only happens. Moreover, the difference in the concentration of the refrigeration oil produced between the compressors caused by the bias is such that the oil concentration can be sufficiently secured by the heat generated by the compressor.

  Usually, the refrigeration oil held in the accumulator is supplied to the compressor via an oil regulator installed in communication with the outer shell at an appropriate height of the compressor by an oil return pipe connected from the bottom of the accumulator. The The oil regulator is composed of a float and a valve linked to the float, and the float detects the proper oil amount position of the compressor and controls the oil amount in the compressor. When the oil amount increases from the appropriate oil amount in each compressor, the float rises, and the valve closes accordingly and the oil supply is stopped. On the contrary, when the oil amount is decreased from the appropriate oil amount in each compressor, the float is lowered, and the valve is opened accordingly, and the oil supply from the oil return pipe is started. The liquid return hole of the accumulator is installed on the bottom side of the U-shaped pipe. Even if the oil return pipe is clogged and the oil level of the accumulator refrigeration machine rises, it is frozen as soon as possible from the liquid return hole of the U-shaped pipe to each compressor. The machine oil can be returned.

Japanese Patent No. 3937884

  However, the conventional refrigeration cycle apparatus as described above has the following problems. For example, in the above refrigerating apparatus, the refrigerant and the refrigerating machine oil are in a compatible combination. However, in the case of a non-compatible and weakly compatible combination, in the accumulator, the upper layer is a refrigerating machine oil rich layer (hereinafter referred to as an oil rich layer). The lower layer is divided into two layers, a refrigerant rich layer. Since the liquid refrigerant in the refrigerant rich layer returns only from the liquid return hole of the U-shaped pipe (refrigerant outflow pipe), the liquid refrigerant having a low oil concentration returns to the compressor. For this reason, the reliability of the compressor may be lowered.

  In addition, since the distance between the refrigerator oil level in the accumulator and the liquid return hole at the bottom of the U-shaped pipe is reduced, if the flow rate of refrigerant increases and the oil level is disturbed, the liquid level will not pass through the liquid return hole even if it is not in the liquid back state. Refrigerator oil flows into the compressor, and the compressor enters a supercharged state. In this case, there has been a possibility that the reliability of the compressor may be lowered, for example, the compressor scroll portion may be damaged due to motor damage due to oil temperature rise or oil compression.

  The present invention has been made to solve the above-described problems, and an object thereof is to obtain an accumulator or the like in which an appropriate amount of refrigerating machine oil returns to the compressor together with the refrigerant.

The accumulator according to the present invention, in an accumulator installed between the evaporator of the refrigeration cycle apparatus and the refrigerant suction side of the compressor, holds liquid refrigerant and refrigerating machine oil that is incompatible or hardly soluble with the refrigerant. In a sealed container, an inflow pipe for allowing the refrigerant containing the refrigerating machine oil from the evaporator to flow into the container, a liquid return hole for letting the liquid refrigerant containing the refrigerating machine oil in the container flow into the pipe, and the container A position that is higher than the liquid return hole, has a suction port for allowing a gaseous or liquid refrigerant to flow into the pipe, and has a plurality of outflow pipes for allowing the refrigerant to flow out to the compressor. The height in the container is equal to or higher than the height of the suction port in the container minus the height related to the amount of refrigerating machine oil filled in the container.

  According to the accumulator of the present invention, the height of the liquid return hole of the outflow pipe in the container is subtracted from the height of the suction port in the container by the height related to the amount of refrigerating machine oil held in the container. Since it is located at the above height, liquid refrigerant with a high oil concentration can be returned to the compressor even when a liquid back occurs regardless of the wetness, and supercharging to the compressor can be performed. The effect that it can prevent and can improve reliability is acquired.

It is a figure which shows the structure of the refrigerating-cycle apparatus which concerns on embodiment of this invention. It is a figure explaining the structure of the accumulator 1 which concerns on Embodiment 1 of this invention. It is a figure explaining the structure of the accumulator 1 which concerns on Embodiment 2 of this invention. It is a figure explaining the structure of the accumulator 1 which concerns on Embodiment 3 of this invention.

Embodiment 1 FIG.
FIG. 1 is a diagram showing a configuration of a refrigeration cycle apparatus according to an embodiment of the present invention. Here, as an example of the refrigeration cycle apparatus, a refrigeration apparatus that cools a target space, an object, and the like will be described. 1 is a refrigerant circuit in which compressors 2a and 2b, oil separators 3a and 3b, a condenser 4, a liquid receiver 5, an expansion valve 6, an evaporator 7 and an accumulator 1 are sequentially connected in an annular manner. Is configured. The compressor 2a and the oil separator 3a, and the compressor 2b and the oil separator 3b are connected in parallel in the refrigerant circuit. Here, when there is no need to particularly distinguish or identify a plurality of similar devices that are distinguished by subscripts, the subscripts may be omitted. Further, the level of temperature, pressure, etc. is not particularly determined in relation to absolute values, but is relatively determined in terms of the state, operation, etc. of the system, apparatus, etc.

  The accumulator 1 has, for example, a container for storing liquid refrigerant or the like so that liquid refrigerant (liquid refrigerant) or the like does not flow into the compressor 2 on the refrigerant suction side of the compressor 2. In the present embodiment, the refrigerating machine oil is separated from the refrigerant (liquid refrigerant and gaseous refrigerant (gas refrigerant)) (hereinafter, a mixture of the refrigerant and the refrigerating machine oil may be described as the refrigerant unless otherwise distinguished). is there). The accumulator 1 will be described in detail later.

  Each of the compressors 2 (2a, 2b) sucks and compresses the refrigerant, and discharges it in a gas state of high temperature and high pressure. The compressor 2 of the present embodiment is a low-pressure shell type compressor in which the inside of a shell such as a scroll has a low pressure, and has a structure in which refrigeration oil is held in the compressor shell. Here, the amount of refrigerating machine oil required in the refrigeration apparatus is not only the amount of oil that is appropriate in the two compressors 2 but also the total amount of refrigerating machine oil flowing through the refrigerant circuit. Therefore, it is assumed that the refrigerating machine oil is filled in the refrigerant circuit with a margin more than the total amount. Here, oil that is incompatible with the refrigerant and weakly compatible is used as the refrigerating machine oil. However, for example, a refrigerating machine oil or the like that becomes compatible at a certain temperature or higher and becomes incompatible or weakly compatible at a temperature lower than a certain temperature may be used. And in the case of a liquid, refrigeration oil shall have a light specific gravity compared with a refrigerant | coolant.

  The oil separators 3 (3a, 3b) are connected to the discharge side of the compressor 2, respectively, and separate the refrigerating machine oil from the discharged refrigerant. The condenser 4 is a heat exchanger that performs heat exchange between, for example, outdoor air or the like (hereinafter referred to as outside air) and a refrigerant to condense and liquefy the refrigerant. The liquid receiver 5 stores liquid refrigerant in order to adjust the refrigerant between the condenser 4 and the evaporator 7, for example. The expansion valve 6 serving as a flow rate adjusting means (throttle device) adjusts the flow rate of the refrigerant and expands it by reducing the pressure. The evaporator 7 is a heat exchanger that performs heat exchange between a cooling target and a refrigerant, evaporates the refrigerant, and cools the cooling target, for example.

  The suction pipes 9 (9a, 9b) are pipes that connect the accumulator 1 and the suction side of the compressor 2, respectively. The oil return pipes 10 (10a, 10b) are pipes through which the refrigerating machine oil separated by the oil separator 3 flows into the suction pipe 9, respectively. The oil return pipes 13 (13a, 13b) are connected to the bottom of the accumulator 1, and are pipes through which refrigeration oil accumulated in the accumulator 1 for supplying (oiling) to the compressor 2 passes. The refrigerating machine oil that has passed through the oil return pipe 13 is supplied to the compressor 2 via an oil regulator 8 that is installed in communication with the outer shell of the compressor 2. The oil regulator 8 (8a, 8b) is composed of, for example, a float and a valve linked to the float, and the float opens and closes the valve based on the oil amount position of the compressor 2 to control the oil amount of the compressor 2. . When the amount of the refrigerating machine oil in the compressor 2 increases from the appropriate oil amount, the float position rises, the valve is closed, and the oil supply from the oil return pipe 13 is stopped. On the contrary, when the amount of the refrigerating machine oil in the compressor 2 decreases from the appropriate oil amount, the float position is lowered, the valve is opened, and the oil is supplied into the compressor 2 through the oil return pipe 13.

  The flow of the refrigerant in the refrigeration cycle apparatus of Embodiment 1 will be described. Each of the compressors 2a and 2b sucks the refrigerant, compresses it, and discharges it in a high-temperature and high-pressure gas state. The discharged refrigerant passes through the oil separators 3 a and 3 b and flows into the condenser 4. The condenser 4 performs heat exchange between outside air supplied from a blower (not shown) and the refrigerant, and condenses and liquefies the refrigerant. The condensed and liquefied refrigerant passes through the expansion valve 6. The expansion valve 6 depressurizes the condensed and liquefied refrigerant passing therethrough. The decompressed refrigerant flows into the evaporator 7. The evaporator 7 evaporates the refrigerant by exchanging heat with the object to be cooled. The evaporated gas refrigerant that has passed through the accumulator 1 branches to the suction pipes 9a and 9b. The branched refrigerant is sucked and discharged by the compressors 2a and 2b, respectively.

  Next, the flow of refrigeration oil in the refrigeration cycle apparatus of Embodiment 1 will be described. As described above, the compressors 2a and 2b each discharge a gas refrigerant, and the discharged gas refrigerant contains refrigeration oil. The oil separators 3a and 3b separate about 90% of the refrigerating machine oil discharged together with the gas refrigerant by the compressors 2a and 2b. The refrigerating machine oil separated from the refrigerant by the oil separators 3a and 3b flows into the suction pipes 9a and 9b through the oil return pipes 10a and 10b, respectively, and is returned to the compressors 2a and 2b through the suction pipes 9a and 9b. The

  On the other hand, the refrigerating machine oil that cannot be separated by the oil separators 3 a and 3 b flows into the accumulator 1 through the condenser 4, the liquid receiver 5, the expansion valve 6, and the evaporator 7. The accumulator 1 separates refrigeration oil and gas refrigerant. The separated oil stays at the bottom of the accumulator 1. The refrigerating machine oil staying in the accumulator 1 is supplied to the compressors 2a and 2b via the oil return pipes 13a and 13b and the oil regulators 8a and 8b.

  FIG. 2 is a view for explaining the structure of the accumulator 1 according to Embodiment 1 of the present invention. FIG. 2 shows a cross-sectional view of the accumulator 1. In FIG. 2, a container main body 21 is a main body of a closed container that becomes the accumulator 1. An oil return pipe 13 is connected to the bottom where the liquid accumulates. The inflow pipe 24 is a pipe through which the refrigerant that has flowed out of the evaporator 7 flows into the container body 21. In the inflow pipe 24, a part of the pipe that goes out of the container main body 21 is at a position higher than the highest part of the pipe in the container main body 21. As a result, when the accumulator 1 stops in a liquid-filled state as shown in FIG. 2 in the liquid-backed state, the oil-rich layer 26 moves to the upstream side of the accumulator 1 (opposite to the connection of the compressor 2). Thus, it is possible to prevent the refrigerating machine oil from being reduced from the accumulator 1. Here, when the mixture of the refrigerant and the refrigerating machine oil flows into the container main body 21 by the operation of the refrigeration apparatus, the mixture is divided into two layers as shown in FIG. Of the two layers, the upper layer is an oil-rich layer 26 containing a large amount of refrigerator oil (the concentration of the refrigerator oil is high), and the lower layer is a refrigerant-rich layer 27.

  One end of the U-shaped pipe (refrigerant outflow pipe) 22 (22a, 22b) passes through the container main body 21 and is connected to the suction pipe 9, and the other end opens in the container main body 21 to serve as a suction port 23. For this reason, the suction port 23 is at a high position in the container main body 21. For example, when the refrigerant has a low wetness, the gas refrigerant is sucked from the suction port 23 and led to the suction pipe 9. The U-shaped tube 22 has a liquid return hole 25. The liquid return hole 25 is a hole for guiding the liquid (mixture) accumulated in the container main body 21 to the suction pipe 9, for example.

  In the accumulator 1 of the present embodiment, the height of the liquid return hole 25 in the container body 21 is determined based on the relationship with the suction port 23 of the U-shaped tube 22. Here, the suction port 23 is positioned at a height equal to or higher than a height corresponding to the amount of refrigerating machine oil held in the container main body 21. For example, it is assumed that the height of the liquid surface when 24 liters of liquid flows into the container body 21 is the position of the suction port 23 in the container body 21.

  Here, as described above, the refrigerating machine oil in the refrigerant circuit is filled with a margin more than the sum of the refrigerating machine oil amount in the compressors 2a and 2b and the oil amount present in each part of the refrigerating apparatus, It is held by the main body 21. For example, when the amount of frozen oil for holding is 8 l, the height of the liquid surface when 16 l of liquid flows, which is 8 l lower than the height of the suction port 23, is set to the container body 21. It is set as the position regarding the height of the liquid return hole 25 in FIG.

However, the liquid is sucked by the pressure difference between the liquid head pressure in the liquid return hole 25 and the pressure loss in the U-shaped tube 22 from the suction port 23 to the liquid return hole 25. For this reason, if the position of the liquid return hole 25 is too high and the difference in height between the suction port 23 and the liquid return hole 25 decreases, the pressure loss of the liquid return hole 25 becomes larger, and the liquid returns to the liquid return hole 25. The liquid return hole 25 is no longer meaningful. Therefore, it is desirable to provide the liquid return hole 25 at a position in consideration of pressure or the like at a height that is lower than the height of the suction port 23 of the U-shaped tube 22 by an amount corresponding to the amount of extra refrigeration oil. For example, the height difference between the suction port 23 of the U-shaped tube 22 and the liquid return hole 25 is set so as to satisfy the relationship of the following expression (1).
Pressure loss of liquid return hole 25 <pressure due to head difference in height between suction port 23 and liquid return hole 25
+ Pressure difference in the U-shaped tube 22 from the suction port 23 to the liquid return hole 25
... (1)

  Further, with respect to the size of the liquid return hole 25, specifically, for example, in a liquid bag with a high wetness level (large liquid back amount), the liquid returns from the suction port 23, and a liquid bag with a low wetness level (liquid back). When the amount is small, the size is set so as to return from the liquid return hole 25. At this time, the refrigeration oil-rich liquid is led from the suction port 23 when the wetness is high, and from the liquid return hole 25 when the wetness is low, and returns to the compressor 2.

  Next, the flow of the refrigerating machine oil and the like in the accumulator 1 in the present embodiment will be described. Here, as described above, it is assumed that the refrigerant and the refrigerating machine oil are a weakly compatible combination. Further, it is assumed that the liquid mixture of the refrigerating machine oil and the liquid refrigerant returns only from the liquid return hole 25 instead of the suction port 23 of the U-shaped tube 22 at the time of low wetness liquid back.

  As described above, since the refrigerating machine oil is held in the accumulator 1, the upper layer is the oil-rich layer 26 and the lower layer is the refrigerant-rich layer 27 in the container body 21 of the accumulator 1. As shown in FIG. 2, a boundary between the oil rich layer 26 and the refrigerant rich layer 27 is formed at a position lower than the liquid return hole 25.

  Therefore, the liquid mixture of the oil rich layer 26 returns to the compressor 2 from the liquid return hole 25 installed at a position lower than the height of the suction port 23 by the amount of oil retained. For this reason, the liquid mixture with a higher oil concentration than the conventional one returns to the compressor 2, and the oil concentration of the compressor 2 at the time of the low wetness liquid back increases from the conventional one. For example, in the accumulator 1 at the time of low-humidity liquid back, the oil concentration of the mixed liquid of the compatible oil is in a uniform state of 25%. On the other hand, in the mixed liquid in which the refrigerant and the refrigerating machine oil are weakly compatible, the oil concentration of the oil rich layer 26 is 40% and the oil concentration of the refrigerant rich layer 27 is 10%. For this reason, the liquid mixture whose oil concentration is 40% is returned. Even in the case of liquid back with high wetness, the oil rich layer 26 returns to the compressor 2 from the suction port 23 of the U-shaped tube 22.

  Further, the oil level of the refrigerating machine oil in the accumulator 1 may rise due to, for example, clogging of the oil return pipe 13. In this case, the diameter of the oil return pipe 13 is increased to make it difficult to clog the pipe. Furthermore, since the distance between the refrigeration machine oil level in the accumulator 1 and the liquid return hole 25 of the U-shaped tube 22 during normal operation can be maintained, the flow rate of the refrigerant increases and the liquid return hole 25 is high even when the oil level is disturbed. By being in the position, it is possible to prevent the refrigerating machine oil from being easily sucked from the liquid return hole 25 and to adjust the refrigerating machine oil amount returning to the compressor 2 to prevent the compressor 2 from being in a supercharged state.

  As described above, according to the accumulator 1 of the refrigeration cycle apparatus of the first embodiment, in the refrigerant circuit, in order to equalize the liquid back amounts of a plurality of compressors piped in parallel, for example, the U-shaped tube 22a, About the liquid return holes 25a and 25b provided in 22b, the height in the container body 21 is lower than the height of the suction port 23 by the amount corresponding to the amount of refrigerating machine oil held in the container body 21. Therefore, the liquid in the oil rich layer 26 having a high oil concentration is led to the suction pipe 9 when the liquid back occurs regardless of the low wetness or the high wetness. Return. For this reason, the compressor 2 malfunction by the refrigeration oil density | concentration fall at the time of a liquid back can be reduced, and the reliability of the compressor 2 and the refrigerating-cycle apparatus can be improved. At this time, it is possible to prevent damage to the motor due to oil temperature rise of the compressor 2 due to supercharging, damage to the compressor scroll portion due to oil compression, etc., and to improve reliability.

Embodiment 2. FIG.
FIG. 3 is a view for explaining the structure of the accumulator 1 according to the second embodiment of the present invention. In the accumulator 1 of the present embodiment, as shown in FIG. 3, oil return holes 29 (29 a, 29 b) for returning the refrigeration machine oil are provided on the lower side surface of each U-shaped tube 22. Here, when the amount of the liquid accumulated in the container main body 21 increases and the oil return hole 29 is immersed in the refrigerant rich layer 27, the amount of the liquid in the refrigerant rich layer 27 returned from the oil return hole 29 to the compressor 2 is reduced. Therefore, the diameter of the oil return hole 29 is smaller than the diameter of the liquid return hole 25. For example, the liquid return hole 25 is set to φ3.0, and the oil return hole 29 is set to φ1.0. Since the amount of refrigerating machine oil to be returned may be smaller than the amount to be returned at the time of liquid back, the oil return hole 29 can have a smaller diameter than the liquid return hole 25.

  Then, when the refrigerating machine oil in the compressor 2 decreases and the refrigerating machine oil in the accumulator 1 increases, the refrigerating machine oil can be returned through the suction pipe 9 so that the oil return pipe 13 is connected. In the present embodiment, the oil return pipe 13 is not connected to the bottom of the accumulator 1 (container body 21).

  As described above, according to the accumulator 1 in the refrigeration cycle apparatus of Embodiment 2, in addition to the liquid return holes 25 (25a, 25b), the oil return holes 29 (29a, 29b) are provided on the lower side surfaces of the U-shaped tubes 22. Since the oil return hole 29 is formed in the U-shaped pipe 22, the oil return hole 29 can be manufactured at a lower cost than the oil return pipe 13, and the cost can be reduced. Moreover, the space concerning piping can be omitted, and simplification of design, installation, etc. can be achieved. Further, since the diameter of the oil return hole 29 is smaller than the liquid return hole 25, the amount of liquid accumulated in the container body 21 is increased, and when the liquid in the refrigerant rich layer 27 covers the oil return hole 29, Even when the liquid in the refrigerant rich layer 27 is immersed in the refrigerant rich layer 27 from the return hole 29 and the oil return hole 29 is immersed in the refrigerant rich layer 27, the liquid back from the refrigerant rich layer is reduced and the malfunction of the compressor 2 due to a decrease in oil concentration is reduced. Can do. At this time, it is possible to prevent damage to the motor due to oil temperature rise of the compressor 2 due to supercharging, damage to the compressor scroll portion due to oil compression, etc., and to improve reliability.

Embodiment 3 FIG.
FIG. 4 is a view for explaining the structure of the accumulator 1 according to Embodiment 3 of the present invention. In the accumulator 1 of this embodiment, as shown in FIG. 4, an oil return hole 29 is provided on the lower side surface of the U-shaped tube 22, and an oil return pipe 13 is connected to the bottom of the accumulator 1 (container body 21). Yes.

  For example, in a device that is actually installed, when the fluctuation of the pipe length between the evaporator 7 and the accumulator 1 and the volume of the evaporator 7 are large, the amount of refrigerating machine oil that the accumulator 1 has may also fluctuate. In this case, even if the amount of the refrigerating machine oil in the compressor 2 decreases, the refrigerating machine oil stays in the pipe length between the evaporator 7 and the accumulator 1 and the volume of the evaporator 7 and the oil amount in the accumulator 1 does not increase. is assumed.

  Therefore, in the refrigeration cycle apparatus of the present embodiment, the refrigeration oil in the container main body 21 is normally returned through the oil return pipe 13 and the oil regulator 8. When the oil level of the refrigerating machine oil in the accumulator 1 rises due to, for example, the oil return pipe 13 being clogged, the refrigerating machine oil can be returned from the oil return hole 29 via the suction pipe 9 as an emergency. To do. At this time, the amount of oil stored in the accumulator 1 that determines the position of the liquid return hole 25 and the like is when the pipe length between the evaporator 7 and the accumulator 1 is the longest and the capacity of the evaporator 7 is the maximum. On the other hand, it is charged assuming that the refrigeration oil stays.

  As described above, according to the accumulator 1 in the refrigeration cycle apparatus of the third embodiment, both the oil return hole 29 and the oil return pipe 13 of the U-shaped tube 22 are provided. Even in the case of the wetness, since the liquid refrigerant having a higher oil concentration than the conventional one returns to the compressor at the time of liquid back, it is possible to reduce a compressor malfunction due to a decrease in the oil concentration at the time of liquid back. Further, since the refrigeration oil can be returned to the compressor 2 from the oil return hole 29, it is possible to prevent the compressor 2 from malfunctioning due to oil exhaustion or the like even when the oil return pipe 13 is clogged. At this time, it is possible to prevent damage to the motor due to oil temperature rise of the compressor 2 due to supercharging, damage to the compressor scroll portion due to oil compression, etc., and to improve reliability.

  In the above-described embodiment, the application to the refrigeration apparatus has been described. The present invention is not limited to these devices, and can also be applied to other refrigeration cycle devices that constitute a refrigerant circuit, such as a heat pump device.

  1 accumulator, 2, 2a, 2b compressor, 3, 3a, 3b oil separator, 4 condenser, 5 receiver, 6 expansion valve, 7 evaporator, 8, 8a, 8b oil regulator, 9, 9a, 9b Suction piping, 10, 10a, 10b Oil return piping, 13, 13a, 13b Oil return piping, 21 Container body, 22, 22a, 22b U-shaped tube, 23, 23a, 23b Suction port, 24 Inflow piping, 25, 25a, 25b Liquid return hole, 26 Oil rich layer, 27 Refrigerant rich layer, 29, 29a, 29b Oil return hole.

Claims (5)

In the accumulator installed between the evaporator of the refrigeration cycle apparatus and the refrigerant suction side of the compressor,
A sealed container containing a liquid refrigerant and refrigerating machine oil that is incompatible or hardly soluble with the refrigerant;
An inflow pipe through which the refrigerant containing the refrigerating machine oil from the evaporator flows into the container;
A liquid return hole for allowing the liquid refrigerant containing the refrigerating machine oil in the container to flow into the pipe and a position higher than the liquid return hole in the container, and a gas or liquid state in the pipe A suction port for allowing refrigerant to flow in, and a plurality of outlet pipes for allowing the compressor to flow out of the refrigerant;
The height of the position of the liquid return hole in the container is equal to or higher than the height of the suction port in the container minus the height related to the amount of refrigerating machine oil filled in the container. An accumulator characterized by being. The outlet pipe is in the low have position than the liquid return hole in the container, the accumulator according to claim 1, further comprising an oil return hole of smaller diameter than the liquid return hole.   The accumulator according to claim 1 or 2, wherein a part of the pipe outside the container of the inflow pipe is at a position higher than a highest part of the pipe in the container. A plurality of compressors for compressing the sucked refrigerant, a condenser for condensing the refrigerant by heat exchange, a flow rate adjusting means for depressurizing the condensed refrigerant, and evaporating the decompressed refrigerant by heat exchange An evaporator,
The refrigerant circuit which circulates the said refrigerant | coolant by pipe-connecting the accumulator as described in any one of Claims 1-3 installed between this evaporator and the refrigerant | coolant suction side of the said compressor is comprised. Refrigeration cycle equipment.   The refrigeration cycle apparatus according to claim 4, further comprising an oil return pipe for supplying the compressor oil in the accumulator to each compressor.

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