JP2011196594A - Refrigeration cycle device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect generation of surplus oil only by simple temperature detection, preventing flowing-out of oil from an oil separator, and ensuring reliability of a compressor.SOLUTION: The compressor 11, the oil separator 12, a condenser 13, a pressure reducing means 14 and an evaporator 15 are annularly connected, these refrigeration cycle components are connected by refrigerant piping 16, further the oil separator 12 has a first opening/closing valve 19, an oil storage container 20, a second opening/closing valve 21 and a second capillary tube 22 in parallel with a first capillary tube 17, and an outlet of the second capillary tube 22 is joined to a connection pipe 18. The refrigerant piping 16 is provided with a first temperature sensor 23, and a second temperature sensor 23 is disposed on a connection pipe 18 between an outlet of the first capillary tube 17 and a joining section of the second capillary tube 22. Further, a first opening/closing valve control means 25 is disposed to control opening/closing of the first opening/closing valve 19 and the second opening/closing valve 21 according to the temperatures detected by the first temperature sensor 23 and the second temperature sensor 24.

Description

  The present invention relates to a surplus oil amount adjusting method in a refrigeration cycle.

  Conventionally, as shown in FIG. 5, the method for adjusting the amount of excess oil stored is such that an oil sump container 7 is arranged in series between an oil separator 2 and an oil return capillary tube 9 via an on-off valve 8 and input in advance. The surplus oil amount is calculated from the length of the refrigerant pipe, and the opening / closing of the on-off valve 8 is controlled at a preset time interval so that the calculated surplus oil amount is obtained, and predetermined oil is returned to the suction pipe of the compressor 1. Thus, the total amount of oil circulating in the refrigeration cycle is controlled (see, for example, Patent Document 1).

Japanese Patent No. 4274235

  However, with this method, it is not possible to accurately grasp the oil retention amount due to the calculation error of the surplus oil amount due to the measurement error of the pipe length, the change of the oil retention amount due to the change in the operating state or the difference in the installation shape of the piping, and the surplus oil retention amount cannot be grasped. Problems include performance degradation due to insufficient oil recovery, etc. and reliability degradation due to excessive recovery. Furthermore, since the oil sump container and the on-off valve are arranged in series with the normal oil return line, if the on-off valve 8 breaks down, there is no oil return from the normal oil separator. And the reliability of the compressor is reduced.

  In order to solve the above problems, the present invention provides a refrigeration cycle apparatus capable of detecting the generation of excess oil only by simple temperature detection, preventing outflow from an oil separator, and ensuring the reliability of the compressor. For the purpose.

  In order to solve the conventional problem, a refrigeration cycle apparatus according to the present invention includes a connecting pipe that connects a discharge side of a compressor to an intake side of the compressor via an oil separator and a first flow path resistor. And a connecting pipe that communicates with the oil separator and is connected in series with the first flow path opening / closing means, the oil sump container, and the second flow path resistance in parallel with the first flow path resistor. It is provided.

  As a result, under operating conditions in which surplus oil is generated, the first flow path opening / closing means can be opened to operate while accumulating surplus oil in the oil sump container, and the surplus oil can flow out into the refrigeration cycle. Can be prevented.

  In addition, since the first flow path opening / closing means is installed in parallel with the first flow path resistor, even if the first flow path opening / closing means is blocked due to a failure or the like, the oil from the normal oil separator A return can be secured.

  Further, the refrigeration cycle apparatus of the present invention communicates with the oil separator, a connection pipe that connects the discharge side of the compressor to the suction side of the compressor via the first flow path resistor. In parallel with the first flow path resistor, an oil sump container, a second flow path opening / closing means, and a connection pipe for sequentially connecting the second flow path resistor in series are provided.

  Thus, under operating conditions in which surplus oil is generated, the second flow path opening / closing means is opened, so that surplus oil is stored in the oil reservoir, and the recovery of the surplus oil is completed by the second flow path opening / closing means. By closing the, the operation can be performed while preventing the excess oil from flowing out into the refrigeration cycle. In addition, the operation can be started in a state where the surplus oil is recovered even at the time of restart.

  In addition, since the second flow path opening / closing means is installed in parallel with the first flow path resistor, the oil from the normal oil separator even when the second flow path opening / closing means is blocked due to a failure or the like. A return can be secured.

  Further, the refrigeration cycle apparatus of the present invention communicates with the oil separator, a connection pipe that connects the discharge side of the compressor to the suction side of the compressor via the first flow path resistor. In parallel with the first flow path resistor, a first flow path opening / closing means, an oil sump container, a second flow path opening / closing means, and a connection pipe for sequentially connecting the second flow path resistance body in series. It is provided.

  As a result, under operating conditions in which surplus oil is generated, surplus oil is stored in the oil sump container by opening the first flow path opening / closing means and the second flow path opening / closing means, and the recovery of the surplus oil is not completed. By closing the first flow path opening / closing means and the second flow path opening / closing means, the excess oil can be reliably recovered in the oil sump container, while preventing the excess oil from flowing out into the refrigeration cycle. You can drive.

  In addition, the operation can be started in a state where the surplus oil is recovered even at the time of restart. In addition, after collecting the excess oil, it is possible to prevent excessive oil accumulation or refrigerant accumulation in the oil reservoir container during operation or during operation stop.

  Further, since the first flow path opening / closing means and the second flow path opening / closing means are installed in parallel to the first flow path resistor, the first flow path opening / closing means or the second flow path opening / closing means. Even when the oil is blocked due to a failure or the like, the oil return from the normal oil separator can be secured.

  According to the present invention, it is possible to provide a refrigeration cycle apparatus that detects the generation of excess oil only by simple temperature detection, prevents outflow from the oil separator, and ensures the reliability of the compressor.

Refrigeration cycle diagram in Embodiment 1 of the present invention Flowchart of on-off valve control in Embodiment 1 of the present invention Refrigeration cycle diagram in Embodiment 2 of the present invention Flowchart of on-off valve control in Embodiment 2 of the present invention Conventional refrigeration cycle diagram

  According to a first aspect of the present invention, the discharge side of the compressor is connected to the suction side of the compressor via an oil separator, a first flow path resistor, and the first separator communicates with the oil separator. In an operating condition in which surplus oil is generated by providing a first channel opening / closing means, an oil reservoir, and a connecting pipe that sequentially connects the second channel resistor in series with the channel resistor. By opening the first flow path opening / closing means, it is possible to operate while accumulating excess oil in the oil reservoir, and to prevent the excess oil from flowing out into the refrigeration cycle, and to reduce the heat transfer performance of the heat exchanger Prevention and pressure loss can be reduced and operation can be performed efficiently.

In addition, since the first flow path opening / closing means is installed in parallel with the first flow path resistor, even if the first flow path opening / closing means is blocked due to a failure or the like, the oil from the normal oil separator The return can be ensured, and the reliability of the compressor can be ensured.

  According to a second aspect of the present invention, the discharge side of the compressor is connected to the suction side of the compressor via an oil separator, a first flow path resistor, and the first separator communicated with the oil separator. In an operating condition in which surplus oil is generated by providing an oil sump container, a second flow path opening / closing means, and a connecting pipe for sequentially connecting the second flow path resistors in series with the flow path resistor. Then, by opening the second flow path opening / closing means, excess oil is stored in the oil reservoir, and when the recovery of the excess oil is completed, the second flow path opening / closing means is closed to enter the refrigeration cycle. It is possible to operate while preventing excess oil from flowing out.

  In addition, the operation can be started in a state where the surplus oil is recovered even at the time of restarting, and the heat transfer performance of the heat exchanger can be prevented from being lowered and the pressure loss can be reduced more efficiently.

  In addition, since the second flow path opening / closing means is installed in parallel with the first flow path resistor, the oil from the normal oil separator even when the second flow path opening / closing means is blocked due to a failure or the like. The return can be ensured, and the reliability of the compressor can be ensured.

  According to a third aspect of the present invention, the discharge side of the compressor is connected to the suction side of the compressor via an oil separator, a first flow path resistor, and the first separator communicates with the oil separator. In parallel with the flow path resistor, the first flow path opening and closing means, the oil sump container, the second flow path opening and closing means, and a connection pipe that sequentially connects the second flow path resistance body, Under the operating conditions in which surplus oil is generated, the first flow path opening / closing means and the second flow path opening / closing means are opened to accumulate surplus oil in the oil sump container. By closing the path opening / closing means and the second flow path opening / closing means, the excess oil can be reliably recovered in the oil reservoir, and the operation can be performed while preventing the excess oil from flowing out into the refrigeration cycle. .

  In addition, the operation can be started in a state where surplus oil has been recovered even after restarting. Further, after the surplus oil has been recovered, excessive oil accumulation or refrigerant in the oil sump container during operation or operation stop Can be prevented, and the heat transfer performance of the heat exchanger can be prevented more effectively and the pressure loss can be reduced to operate efficiently.

  Further, since the first flow path opening / closing means and the second flow path opening / closing means are installed in parallel to the first flow path resistor, the first flow path opening / closing means or the second flow path opening / closing means. Even when the oil is blocked due to a failure or the like, the oil return from the normal oil separator can be secured, and the reliability of the compressor can be secured.

  The fourth invention is the first temperature sensor provided in the discharge pipe of the compressor, the second temperature sensor provided in the connection pipe on the outlet side of the first flow path resistor, in particular in the first invention, Control means, and when the temperature difference detected by the first temperature sensor and the second temperature sensor is less than or equal to a predetermined value, the first flow path opening / closing means is opened, and the predetermined value When larger than this, by closing, when surplus oil is generated in the refrigeration cycle during operation, only the oil flows through the first flow path resistor, and the temperature drop is small even after decompression. The temperature difference between the first flow path resistor outlet temperature detected by the second temperature sensor and the discharge temperature detected by the first temperature sensor becomes small.

  For this reason, generation | occurrence | production of surplus oil can be detected, and when surplus oil generate | occur | produces, it operates by storing the surplus oil in an oil reservoir container by opening the first flow path opening / closing means, and enters the refrigeration cycle. It is possible to prevent the excess oil from flowing out.

  In addition, when there is no surplus oil generation, the amount of oil in the refrigeration cycle can be optimized by closing the first flow path opening / closing means, so that the heat transfer performance of the heat exchanger can be prevented from being lowered. The pressure loss can be reduced and the operation can be efficiently performed, and the amount of oil circulating in the refrigeration cycle can be optimized, so that the reliability of the compressor can be improved.

  The fifth invention is the first temperature sensor provided in the discharge pipe of the compressor, and the second temperature sensor provided in the connection pipe on the outlet side of the first flow path resistor, particularly in the second invention, Control means, and when the temperature difference detected by the first temperature sensor and the second temperature sensor is less than or equal to a predetermined value, the second flow path opening / closing means is opened, and the predetermined value When larger than this, by closing, when surplus oil is generated in the refrigeration cycle during operation, only the oil flows through the first flow path resistor, and the temperature drop is small even after decompression. The temperature difference between the first flow path resistor outlet temperature detected by the second temperature sensor and the discharge temperature detected by the first temperature sensor becomes small.

  For this reason, it is possible to detect the generation of surplus oil. When the generation of surplus oil is detected, the second flow path opening / closing means is opened to operate while collecting the surplus oil in the oil sump container. When it is detected that the oil has run out, the second flow path opening / closing means is closed, and the operation can be performed in a state where excess oil is collected in the oil reservoir.

  In addition, the operation can be started with the excess oil recovered even at the time of restart, and the heat transfer performance of the heat exchanger can be prevented more effectively and the pressure loss can be reduced and the operation can be efficiently performed. Since the amount of oil circulating in the cycle can be optimized, the reliability of the compressor can be improved.

  In a sixth aspect based on the first aspect, the first temperature sensor provided in the discharge pipe of the compressor, the second temperature sensor provided in the connection pipe on the outlet side of the first flow path resistor, and control And when the temperature difference detected by the first temperature sensor and the second temperature sensor is equal to or less than a predetermined value, the first channel opening / closing unit and the second channel opening / closing When the means is opened and is larger than the predetermined value, it is closed, and when surplus oil is generated in the refrigeration cycle during operation, only the oil flows through the first flow path resistor, Since the temperature drop is small even after the pressure reduction, the temperature difference between the first flow path resistor outlet temperature detected by the second temperature sensor and the discharge temperature detected by the first temperature sensor becomes small.

  For this reason, generation | occurrence | production of surplus oil can be detected, and when generation | occurrence | production of surplus oil is detected, the surplus oil is stored in the oil reservoir container by opening the first flow path opening / closing means and the second flow path opening / closing means. When the excess oil is detected, the first flow path opening / closing means and the second flow path opening / closing means are closed so that the excess oil is recovered in the oil reservoir. be able to.

  In addition, the operation can be started in a state where the surplus oil is recovered even at the time of restart. In addition, after collecting the excess oil, it is possible to prevent excessive oil accumulation and refrigerant accumulation in the oil reservoir container during operation or shutdown, and more effectively reduce the heat transfer performance of the heat exchanger. In addition, the reliability of the compressor can be improved because the amount of oil circulating in the refrigeration cycle can be optimized.

A seventh invention is the first invention, comprising: a first temperature sensor provided in the suction pipe of the compressor; a second temperature sensor provided on the outlet side of the evaporator; and a control means. When the temperature difference detected by the first temperature sensor and the second temperature sensor is greater than or equal to a predetermined value, the first flow path opening / closing means is opened, and when the temperature difference is smaller than the predetermined value, the first flow sensor is closed. As a result, when excess oil is generated in the refrigeration cycle during operation, only the oil flows through the first flow path resistor, and the temperature drop is small even after the pressure is reduced. A large amount of oil flows in.

  For this reason, the suction temperature of the compressor detected by the first temperature sensor starts to rise, and the temperature difference from the piping temperature detected by the second temperature sensor installed upstream from the high temperature oil junction increases. Therefore, the generation of surplus oil can be detected, and when surplus oil is generated, the first flow path opening / closing means is opened to operate while accumulating the surplus oil in the oil sump container, and into the refrigeration cycle. It is possible to prevent excess oil from flowing out.

  In addition, when there is no surplus oil generation, the amount of oil in the refrigeration cycle can be optimized by closing the first flow path opening / closing means, so that the heat transfer performance of the heat exchanger can be prevented from being lowered. The pressure loss can be reduced and the operation can be efficiently performed, and the amount of oil circulating in the refrigeration cycle can be optimized, so that the reliability of the compressor can be improved.

  An eighth invention is the second invention, comprising a first temperature sensor provided in the suction pipe of the compressor, a second temperature sensor provided on the outlet side of the evaporator, and a control means, When the temperature difference detected by the first temperature sensor and the second temperature sensor is greater than or equal to a predetermined value, the second flow path opening / closing means is opened, and when the temperature difference is smaller than the predetermined value, it is closed. As a result, when excess oil is generated in the refrigeration cycle during operation, only the oil flows through the first flow path resistor, and the temperature drop is small even after the pressure is reduced. A large amount of oil flows in.

  For this reason, the suction temperature of the compressor detected by the first temperature sensor starts to rise, and the temperature difference from the piping temperature detected by the second temperature sensor installed upstream from the high temperature oil junction increases. Therefore, it is possible to detect the generation of surplus oil. When the generation of surplus oil is detected, the second flow path opening / closing means is opened to operate while collecting the surplus oil in the oil sump container. When it is detected that the oil has disappeared, the second flow path opening / closing means is closed, so that the operation can be performed in a state where surplus oil is collected in the oil reservoir.

  In addition, the operation can be started with the excess oil recovered even at the time of restart, and the heat transfer performance of the heat exchanger can be prevented more effectively and the pressure loss can be reduced and the operation can be efficiently performed. Since the amount of oil circulating in the cycle can be optimized, the reliability of the compressor can be improved.

  A ninth invention comprises the first temperature sensor provided in the suction pipe of the compressor, the second temperature sensor provided on the outlet side of the evaporator, and control means in the first invention, When the temperature difference detected by the first temperature sensor and the second temperature sensor is greater than or equal to a predetermined value, the first flow path opening / closing means and the second flow path opening / closing means are opened, When the oil is smaller than the predetermined value, by closing, when surplus oil is generated in the refrigeration cycle during operation, only the oil flows through the first flow path resistor, and the temperature decreases even after the pressure is reduced. Since it is small, a large amount of hot oil flows into the suction pipe of the compressor.

  For this reason, the suction temperature of the compressor detected by the first temperature sensor starts to rise, and the temperature difference from the piping temperature detected by the second temperature sensor installed upstream from the high temperature oil junction increases. Therefore, the generation of surplus oil can be detected, and when the generation of surplus oil is detected, the surplus oil is put into the sump container by opening the first channel opening / closing means and the second channel opening / closing means. When operating while collecting and detecting that the excess oil is gone, close the first channel opening and closing means and the second channel opening and closing means to operate with the excess oil recovered in the oil reservoir. Can do.

  In addition, the operation can be started with the surplus oil collected even at the time of restart, and after the surplus oil is collected, excessive oil accumulation or refrigerant in the oil sump container during operation or operation stop It is possible to prevent the accumulation of heat, prevent the heat transfer performance of the heat exchanger from decreasing more efficiently, reduce pressure loss and operate efficiently, and optimize the amount of oil circulating in the refrigeration cycle Therefore, the reliability of the compressor can be improved.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the present invention is not limited to the embodiments.

(Embodiment 1)
FIG. 1 is a refrigeration cycle diagram according to the first embodiment of the present invention, and FIG. 2 is a flowchart of on-off valve control.

  In FIG. 1, a compressor 11, an oil separator 12, a condenser 13, a pressure reducing means 14, and an evaporator 15 are connected in an annular shape to form a refrigeration cycle. These refrigeration cycle components are connected to each other by a refrigerant pipe 16, the compressor 11 and the oil separator 12 are refrigerant pipe 16 a, the oil separator 12 and the condenser 13 are refrigerant pipe 16 b, and the condenser 13 and the evaporator 15 are decompressed. The refrigerant pipe 16c, the evaporator 15, and the compressor 11 are connected via the means 14 by the refrigerant pipe 16d. The oil separator 12 is connected to the refrigerant pipe 16d by a connecting pipe 18 through a first capillary tube 17 (first flow path resistor).

  Further, the oil separator 12 includes a first open / close valve 19 (first flow path opening / closing means), an oil sump container 20 and a second open / close valve in parallel with the first capillary tube 17 (first flow path resistor). 21 (second flow path opening / closing means) and a second capillary tube 22 (second flow path resistor), and the outlet of the second capillary tube 22 (second flow path resistor) is connected pipe 18 To join. In addition, the refrigerant pipe 16a is provided with a first temperature sensor 23, which is located on the connection pipe 18 and has an outlet of the first capillary 17 (first flow path resistor) and a second capillary 22 (second flow). The second temperature sensor 24 is installed between the merging portions of the path resistors).

  Further, the first on-off valve 19 (first channel opening / closing means) and the second on-off valve 21 (second channel opening / closing) according to the detected temperatures of the first temperature sensor 23 and the second temperature sensor 24. First on-off valve control means 25 for controlling the opening and closing of the means).

  The operation and action of the refrigeration cycle configured as described above will be described below with reference to FIG.

  The high-pressure gas refrigerant and oil discharged from the compressor 11 flow into the oil separator 12 and are separated into the high-pressure gas refrigerant and oil. The separated high-pressure gas refrigerant flows into the condenser 13 and is condensed and liquefied. The condensed and liquefied high-pressure liquid refrigerant is decompressed by the decompression means 14, becomes a low-pressure gas-liquid two-phase refrigerant, and flows into the evaporator 15. The gas-liquid two-phase refrigerant that has flowed into the evaporator 15 absorbs heat, becomes low-pressure gas refrigerant, and is sucked into the compressor 11 again.

  On the other hand, the oil separated by the oil separator 12 flows into the refrigerant pipe 16d through the connecting pipe 18 while being decompressed by the first capillary tube 17 (first flow path resistor) together with a part of the gas refrigerant. It is sucked into the compressor 11 together with the gas refrigerant.

In such a circulation state of the refrigerant and oil, the oil discharged together with the refrigerant from the compressor 11 is separated by the oil separator 12, and most of the oil is separated from the first capillary tube 17 (first flow path resistor). Oil is returned to the suction pipe of the compressor 11 through the connection pipe 18, but a part passes through the oil separator 12 and flows out to the heat exchanger side. The oil that has passed through the oil separator 12 passes through the condenser 13.
Returning to the compressor 11 while partly staying in the evaporator 15 and the refrigerant pipe 16.

  That is, when the refrigerant pipe 16 is long, the oil retention amount increases, and when it is short, the retention amount decreases. For this reason, the compressor 11 is preliminarily filled with oil in consideration of the maximum residence amount in consideration of the case where the residence amount increases.

  Therefore, when such a compressor 11 is mounted in a refrigeration cycle apparatus having a short refrigerant pipe 16, the amount of oil enclosed in the compressor 11 becomes excessive, generating excess oil, and the condenser 13 and the evaporator 15 The oil stays in the refrigerant pipe 16 excessively, which causes a decrease in heat transfer performance of the heat exchanger and a decrease in performance due to an increase in pressure loss.

  When the operation is in an excessive oil amount state (excess oil generation state), the amount of oil returned to the compressor 11 increases and the amount of oil in the compressor 11 also increases. As the amount of oil in the compressor 11 increases, the amount of oil discharged from the compressor 11 increases and the amount of oil flowing into the oil separator 12 also increases.

  In the oil separator 12, the refrigerant and oil that have flowed are separated, and the separated oil flows into the refrigerant pipe 16 d through the first capillary tube 17 (first flow path resistor) and the connection pipe 18. When the amount of oil flowing into the separator 12 is excessive, the amount of oil to be separated also increases, so that the first capillary tube 17 (first flow path resistor) cannot return and starts to accumulate at the bottom of the oil separator 12.

  When the excess oil that has started to accumulate in the oil separator 12 exceeds a predetermined amount, the separation performance of the oil separator 12 decreases, and the oil flowing out from the oil separator 12 toward the condenser 13 increases, The amount of oil staying in the evaporator 15 and the refrigerant pipe 16 increases.

  Next, the operation of the on-off valve will be described with reference to the flowchart of FIG.

  First, the first on-off valve 19 (first flow path opening / closing means) is closed, and the second on-off valve 21 (second flow path opening / closing means) is opened (step S1). Next, the discharge temperature T1 of the compressor is measured by the first temperature sensor 22, and the connecting pipe temperature T2 is measured by the second temperature sensor 24 (step S2).

  At this time, when only the separated oil flows through the first capillary tube 17 (first flow path resistor) in an excess oil state, the circulating oil is high-temperature oil discharged from the compressor 11, Even if this high-temperature oil passes through the first capillary tube 17 (first flow path resistor), it does not expand, so there is almost no temperature drop. Here, the compressor discharge temperature T1 measured in step S2 and the connecting pipe temperature T2 are compared (step S3).

  The temperature difference t1 is compared based on the detected temperature. If the temperature difference t1 is equal to or less than the predetermined temperature difference t1, the first on-off valve control means 25 is connected to the first on-off valve 19 (first flow path opening / closing means). Is released (step S4).

  When the first opening / closing valve 19 (first flow path opening / closing means) is opened in step S4, the excess oil accumulated in the oil separator 12 is stored in the oil reservoir 20 and the second capillary 22 (second flow path). It begins to flow to the connecting pipe 18 through the resistor. At this time, since the second capillary 22 (second flow path resistor) is connected to the downstream portion of the oil reservoir container 20, the oil flowing into the oil reservoir container 20 enters the oil reservoir container 20. It begins to accumulate gradually. Thereby, the surplus oil amount in the oil separator 12 starts to decrease.

  In such a state, when the excess oil in the oil separator 12 is reduced by repeating Step S2, Step S3, and Step S4, the first capillary 17 (first flow path resistor) is put together with the oil. High-pressure gas refrigerant begins to flow. When the high-pressure gas refrigerant flows through the first capillary tube 17 (first flow path resistor), the refrigerant gas expands under reduced pressure, and its temperature decreases. This indicates that excess oil is not accumulated in the oil separator 12.

  At this time, if the temperature difference is equal to or greater than the predetermined temperature difference t1 in step S3, first, the state of the first on-off valve (first flow path opening / closing means) is confirmed (step S5).

  In step S5, when the first on-off valve 19 (first flow path opening / closing means) is in the open state, it indicates that the surplus oil is being collected into the oil reservoir 20 and in this state, Since the temperature difference is equal to or greater than t1, it is determined that there is no excess oil in the oil separator 12, and the first opening / closing valve 19 (first flow path opening / closing means) and the second opening / closing valve 21 (second Both the channel opening / closing means are closed (step S6).

  On the other hand, if the first on-off valve 19 (first flow path opening / closing means) is already closed in step S5, it indicates that no excess oil is generated in the oil separator 12. Subsequently, Step S1, Step S2, Step S3, and Step S5 are repeated, and monitoring of excess oil generation is continued.

  By repeating the operation as described above, the generation of surplus oil is reliably detected, and when surplus oil is generated, the first on-off valve 19 (first flow path opening / closing means) and the second on-off valve 21 are detected. When the oil return amount from the oil separator 12 is controlled by opening / closing control of the (second flow path opening / closing means) and surplus oil is generated, the surplus oil is recovered in the oil sump container 20 and the oil separator 12 is recovered. The amount of oil flowing out from the condenser 13, the evaporator 15, and the refrigerant pipe 16 can be reduced, and the amount of oil remaining in the condenser 13, the evaporator 15, and the refrigerant pipe 16 can be reduced.

  In addition, when the operation is completed in a state where surplus oil has been collected, the first on-off valve 19 (first flow path opening / closing means) and the second on-off valve 21 (second flow path opening / closing means) are turned off. In the case of the specification, it can be restarted while retaining the recovered surplus oil, and operation can be resumed efficiently.

  Furthermore, there is no accumulation of excess refrigerant in the oil sump container 20 during the stop, and the reliability performance can be improved.

  Further, the first on-off valve 19 (first flow path opening / closing means), the oil reservoir 20 and the second on-off valve 21 (second flow path opening / closing means) for recovering excess oil are provided in the first Since the capillaries 17 (first flow path resistors) are arranged in parallel, the first on-off valve 19 (first flow path opening / closing means) or the second on-off valve 21 (second flow path opening / closing means). ), The oil return from the normal oil separator 12 can be ensured, so that the reliability of the compressor 11 can be ensured.

  Note that either the first on-off valve 19 (first flow path opening / closing means) and the second on-off valve 21 (second flow path opening / closing means) installed at the inlet and outlet of the oil reservoir 20 are either. One side may be sufficient and the same effect is acquired about collection | recovery of excess oil.

(Embodiment 2)
FIG. 3 is a refrigeration cycle diagram according to the second embodiment of the present invention, and FIG. 4 is a flowchart of on-off valve control.

In the refrigeration cycle of the present embodiment, the first temperature sensor 26 is installed on the suction pipe of the compressor 11 (on the compressor side with respect to the connection position of the connection pipe 18 and the refrigerant pipe 16d), and the second temperature sensor 27 is installed.
Is installed on the upstream side (evaporator 15 side) from the connection position of the connection pipe 18 and the refrigerant pipe 16d, and the second on-off valve control means 28 is provided.

  The operation and action of the refrigeration cycle configured as described above will be described below with reference to FIG. About the flow of a refrigerant and oil, it is the same as that of Embodiment 1, and explanation is omitted.

  When the operation is in an excessive oil amount state (excess oil generation state), the amount of oil returned to the compressor 11 increases and the amount of oil in the compressor 11 also increases. As the amount of oil in the compressor 11 increases, the amount of oil discharged from the compressor 11 increases and the amount of oil flowing into the oil separator 12 also increases.

  In the oil separator 12, the refrigerant and oil that have flowed are separated, and the separated oil flows into the refrigerant pipe 16 d through the first capillary tube 17 (first flow path resistor) and the connection pipe 18. When the amount of oil flowing into the separator 12 is excessive, the amount of oil to be separated also increases, so that the first capillary tube 17 (first flow path resistor) cannot return and starts to accumulate at the bottom of the oil separator 12.

  When the excess oil that has started to accumulate in the oil separator 12 exceeds a predetermined amount, the separation performance of the oil separator 12 decreases, and the oil flowing out from the oil separator 12 toward the condenser 13 increases, The amount of oil staying in the evaporator 15 and the refrigerant pipe 16 increases.

  Next, the operation of the on-off valve will be described with reference to the flowchart of FIG.

  First, the first on-off valve 19 (first flow path opening / closing means) is closed, and the second on-off valve 21 (second flow path opening / closing means) is opened (step S1).

  Next, the first temperature sensor 26 measures the suction temperature T3 of the compressor, and the second temperature sensor 27 measures the temperature T4 of the refrigerant pipe 16d upstream of the position where the return oil flows (step S2). .

  At this time, when only the separated oil flows through the first capillary tube 17 (first flow path resistor) in an excess oil state, the circulating oil is high-temperature oil discharged from the compressor 11, Even if this high-temperature oil passes through the first capillary tube 17 (first flow path resistor), it does not expand, so there is almost no temperature drop. Here, the compressor suction temperature T3 measured in step S2 is compared with the temperature T4 of the refrigerant pipe 16d on the upstream side of the position where the return oil flows (step S3).

  The temperature difference t2 is compared based on the detected temperature. If the temperature difference t2 is equal to or greater than the predetermined temperature difference t2, the first on-off valve control means 25 is connected to the first on-off valve 19 (first flow path opening / closing means). Is released (step S4).

  When the first opening / closing valve 19 (first flow path opening / closing means) is opened in step S4, surplus oil accumulated in the oil separator 12 flows to the connecting pipe 18 through the oil reservoir 20 and the second capillary tube 22. start. At this time, since the second capillary 22 (second flow path resistor) is connected to the downstream portion of the oil reservoir container 20, the oil flowing into the oil reservoir container 20 enters the oil reservoir container 20. It begins to accumulate gradually. Thereby, the surplus oil amount in the oil separator 12 starts to decrease.

When the excess oil in the oil separator 12 is reduced by repeating Step S2, Step S3, and Step S4 in such a state, the first capillary 17 (first flow path resistor)
High-pressure gas refrigerant begins to flow in along with the oil. When the high-pressure gas refrigerant flows through the first capillary tube 17 (first flow path resistor), the refrigerant gas expands under reduced pressure, and its temperature decreases. This indicates that excess oil is not accumulated in the oil separator 12.

  At this time, if the temperature difference is equal to or smaller than the predetermined temperature difference t2 in step S3, first, the state of the first on-off valve (first flow path opening / closing means) is confirmed (step S5).

  In step S5, when the first on-off valve 19 (first flow path opening / closing means) is in the open state, it indicates that the surplus oil is being collected into the oil reservoir 20 and in this state, Since the temperature difference is equal to or greater than t1, it is determined that there is no excess oil in the oil separator 12, and the first opening / closing valve 19 (first flow path opening / closing means) and the second opening / closing valve 21 (second Are closed together (step S6).

  On the other hand, if the first on-off valve 19 (first flow path opening / closing means) is already closed in step S5, it indicates that no excess oil is generated in the oil separator 12. Subsequently, Step S1, Step S2, Step S3, and Step S5 are repeated, and monitoring of excess oil generation is continued.

  By repeating the operation as described above, the generation of surplus oil is reliably detected, and when surplus oil is generated, the first on-off valve 19 (first flow path opening / closing means) and the second on-off valve 21 are detected. When the oil return amount from the oil separator 12 is controlled by opening / closing control of the (second flow path opening / closing means) and surplus oil is generated, the surplus oil is recovered in the oil sump container 20 and the oil separator 12 is recovered. The amount of oil flowing out from the condenser 13, the evaporator 15, and the refrigerant pipe 16 can be reduced, and the amount of oil remaining in the condenser 13, the evaporator 15, and the refrigerant pipe 16 can be reduced.

  In addition, when the operation is completed in a state where surplus oil has been collected, the first on-off valve 19 (first flow path opening / closing means) and the second on-off valve 21 (second flow path opening / closing means) are turned off. In the case of the specification, it can be restarted while retaining the recovered surplus oil, and operation can be resumed efficiently.

  Furthermore, there is no accumulation of excess refrigerant in the oil sump container 20 during the stop, and the reliability performance can be improved.

  Further, the first on-off valve 19 (first flow path opening / closing means), the oil reservoir 20 and the second on-off valve 21 (second flow path opening / closing means) for recovering excess oil are provided in the first Since the capillaries 17 (first flow path resistors) are arranged in parallel, the first on-off valve 19 (first flow path opening / closing means) or the second on-off valve 21 (second flow path opening / closing means). ), The oil return from the normal oil separator 12 can be ensured, so that the reliability of the compressor 11 can be ensured.

  Note that either the first on-off valve 19 (first flow path opening / closing means) and the second on-off valve 21 (second flow path opening / closing means) installed at the inlet and outlet of the oil reservoir 20 are either. One side may be sufficient and the same effect is acquired about collection | recovery of excess oil.

  As described above, the refrigeration cycle apparatus according to the present invention reliably detects the generation of excess oil in the refrigeration cycle and reduces the amount of excess oil flowing out to the heat exchanger side. Therefore, it can be applied to various refrigeration cycle apparatuses such as an air conditioner refrigeration cycle apparatus, a car air conditioner, and a heat pump water heater.

DESCRIPTION OF SYMBOLS 11 Compressor 12 Oil separator 13 Condenser 14 Decompression means 15 Evaporator 16 Refrigerant piping 17 1st capillary 18 First connection pipe 19 1st on-off valve 20 Oil sump container 21 2nd on-off valve 22 2nd Capillary tube 23 First temperature sensor 24 Second temperature sensor 25 First on-off valve control means 26 First temperature sensor 27 Second temperature sensor 28 Second on-off valve control means

Claims (9)

The discharge side of the compressor is connected to the suction side of the compressor via an oil separator and a first flow path resistor, and the first flow path resistor communicates with the oil separator. A refrigeration cycle apparatus comprising a first pipe opening / closing means, an oil reservoir, and a connecting pipe for sequentially connecting a second passage resistor in series in parallel. The discharge side of the compressor is connected to the suction side of the compressor via an oil separator and a first flow path resistor, and the first flow path resistor communicates with the oil separator. A refrigeration cycle apparatus comprising an oil sump container, a second channel opening / closing means, and a connecting pipe for sequentially connecting a second channel resistor in series in parallel. The discharge side of the compressor is connected to the suction side of the compressor via an oil separator and a first flow path resistor, and the first flow path resistor communicates with the oil separator. A refrigeration cycle apparatus comprising a first flow path opening / closing means, an oil reservoir, a second flow path opening / closing means, and a connecting pipe for connecting the second flow path resistors in series in parallel. . A first temperature sensor provided in a discharge pipe of the compressor; a second temperature sensor provided in a connection pipe on the outlet side of the first flow path resistor; and a control means; When the temperature difference detected by the second temperature sensor is less than a predetermined value, the first flow path opening / closing means is opened, and when the temperature difference is larger than the predetermined value, it is closed. The refrigeration cycle apparatus according to claim 1. A first temperature sensor provided in a discharge pipe of the compressor; a second temperature sensor provided in a connection pipe on the outlet side of the first flow path resistor; and a control means; The second flow path opening / closing means is opened when the temperature difference detected by the second temperature sensor is equal to or smaller than a predetermined value, and is closed when the temperature difference is larger than the predetermined value. The refrigeration cycle apparatus according to claim 2. A first temperature sensor provided in a discharge pipe of the compressor; a second temperature sensor provided in a connection pipe on the outlet side of the first flow path resistor; and a control means; When the temperature difference detected by the second temperature sensor is equal to or smaller than a predetermined value, the first flow path opening / closing means and the second flow path opening / closing means are opened and the temperature difference is larger than the predetermined value. The refrigeration cycle apparatus according to claim 3, wherein the refrigeration cycle apparatus is closed. A first temperature sensor provided on a suction pipe of the compressor; a second temperature sensor provided on an outlet side of the evaporator; and a control unit, wherein the first temperature sensor, the second temperature sensor, 2. The refrigeration according to claim 1, wherein when the temperature difference detected in step 1 is equal to or greater than a predetermined value, the first flow path opening / closing means is opened, and when the temperature difference is smaller than the predetermined value, it is closed. Cycle equipment. A first temperature sensor provided on a suction pipe of the compressor; a second temperature sensor provided on an outlet side of the evaporator; and a control unit, wherein the first temperature sensor, the second temperature sensor, The refrigeration according to claim 2, wherein when the temperature difference detected in step (b) is greater than or equal to a predetermined value, the second flow path opening / closing means is opened, and when the temperature difference is smaller than the predetermined value, the second flow path opening / closing means is closed. Cycle equipment. A first temperature sensor provided on a suction pipe of the compressor; a second temperature sensor provided on an outlet side of the evaporator; and a control unit, wherein the first temperature sensor, the second temperature sensor, If the temperature difference detected in step (b) is greater than or equal to a predetermined value, the first flow path opening / closing means and the second flow path opening / closing means are opened. If the temperature difference is smaller than the predetermined value, the first flow path opening / closing means is closed. The refrigeration cycle apparatus according to claim 3, wherein

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