JP4583280B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus for diverting refrigerant discharged from a radiator into first and second refrigerant flows by refrigerant diverting means.

  In this type of refrigeration system, a refrigeration cycle is composed of a compression means, a radiator, a throttling means, an evaporator, etc., and the refrigerant compressed by the compression means dissipates heat in the radiator and is depressurized by the throttling means before evaporating. Evaporate by exchanging heat with the surroundings. At this time, ambient air was cooled by evaporation of the refrigerant, and the space to be frozen was cooled.

  In recent years, in this type of refrigeration apparatus, it has become impossible to use chlorofluorocarbon refrigerants due to natural environmental problems, and for example, attempts have been made to use carbon dioxide, which is a natural refrigerant. Since the carbon dioxide refrigerant has a low critical pressure, it becomes supercritical on the high pressure side of the refrigerant cycle due to compression. In this case, the specific enthalpy of the refrigerant at the inlet of the evaporator increases under the condition that the refrigerant temperature at the radiator outlet becomes high due to the heat source temperature on the radiator side being high. It was. In this case, in order to ensure the refrigerating capacity, it is necessary to increase the high pressure, resulting in an increase in compression power and a decrease in coefficient of performance.

By the way, the compression means of the refrigeration apparatus is filled with oil for lubricating the sliding portion, and the oil is supplied to the sliding portion of the compression means for lubrication and sealing. Compressed together with the refrigerant and discharged to the outside of the compression means, resulting in a disadvantage that the oil is insufficient. Further, when the discharged oil circulates in the refrigerant cycle, there is a problem that the refrigerant stagnates in an evaporator or the like in the refrigerant cycle and hinders the circulation of the refrigerant. Therefore, a refrigeration apparatus having oil separation means for separating oil mixed in refrigerant gas on the discharge side of the compression means and returning it to the compression means has been developed (for example, Patent Document 1 or Patent Document). 2).
JP 2000-274890 A JP-A-6-337171

  In this case, in a refrigeration apparatus using a refrigerant whose high pressure side is a supercritical pressure, such as carbon dioxide refrigerant, when the oil is separated after the radiator as in Patent Document 1, the refrigerant is cooled by the radiator. Since the refrigerant enters a pseudo-critical state and the refrigerant and oil are in an unstable dissolved state, the oil cannot be smoothly separated from the refrigerant depending on conditions. For this reason, the above-described shortage of oil in the compression means and oil accumulation in the refrigeration cycle cannot be resolved, and further, a pressure loss is generated, resulting in a disadvantage that the performance is deteriorated.

  On the other hand, if the oil is separated at the discharge part of the compression means and directly returned to the sealed container as in Patent Document 2, the oil is returned at a high pressure, so that the fixed throttle mechanism is caused by fluctuations in rotational speed or high pressure. It is impossible to cope with fluctuations in differential pressure. Further, since the temperature of the oil returns to a high state, the temperature of the closed container of the compression means and the motor temperature rises, causing problems that cause efficiency reduction and oil deterioration. In particular, when the carbon dioxide refrigerant is used and the high-pressure side is at a high pressure, the above problem becomes significant.

  The present invention has been made to solve the problems of the related art, and is intended to improve the coefficient of performance by reducing the compression power of the compression means, and to mix the oil mixed in the refrigerant discharged from the compression means It aims at providing the freezing apparatus which can isolate | separate effectively and can return to a compression means.

  In the refrigeration apparatus of the present invention, a refrigeration cycle is composed of a compression means, a radiator, a main throttle means, an evaporator, an auxiliary throttle means, and an internal heat exchanger. The refrigerant is branched into the first and second refrigerant flows by the refrigerant branching means, and the first refrigerant flow is caused to flow through the first passage of the internal heat exchanger, and then flows from the main throttle means to the evaporator, The refrigerant flow is flowed from the auxiliary throttle means to the second passage of the internal heat exchanger, the first refrigerant flow and the second refrigerant flow are exchanged in the internal heat exchanger, and the refrigerant discharged from the evaporator is compressed by the compression means. The refrigerant discharged from the second passage of the internal heat exchanger is sucked into the intermediate pressure part of the compression means, and oil is discharged from the refrigerant discharged from the compression means and flowing into the radiator. An oil separation means is provided for separation, and the oil separation means Characterized in that are merged into a second refrigerant flow flowing into the auxiliary throttle means at the confluence means provided on the inlet side of the auxiliary throttle means an oil.

  According to a second aspect of the present invention, there is provided a refrigeration apparatus including an oil radiator for cooling the oil separated by the oil separation means in the above invention.

  A refrigeration apparatus according to a third aspect of the invention is characterized in that in the second aspect of the invention, the oil separating means separates the refrigerant containing a large amount of oil, and the refrigerant containing a large amount of oil flows into the oil radiator.

  A refrigeration apparatus according to a fourth aspect of the invention is characterized in that in the invention of the second or third aspect, the oil separating means and / or the heat radiator for oil are integrally formed with the heat radiator.

  The invention of claim 5 is characterized in that in the invention of the refrigeration apparatus according to any one of claims 2 to 4, a throttle means is provided on the outlet side of the oil radiator.

  The refrigeration apparatus according to the invention of claim 6 is characterized in that, in each of the above inventions, a throttle means is provided between the refrigerant branching means and the merging means.

  The invention of claim 7 is characterized in that in the invention of the refrigeration apparatus according to any one of claims 1 to 5, the refrigerant branching means and the merging means are integrally formed.

  In the refrigeration apparatus according to an eighth aspect of the present invention, in each of the above inventions, the compression means is composed of a low-stage compression means and a high-stage compression means housed in a sealed container together with a drive means constituting the compression means, The low-stage compression means sucks and compresses the refrigerant discharged from the evaporator, discharges it into the sealed container, and the refrigerant and oil output from the second passage of the internal heat exchanger flow into the sealed container, The high-stage compression means sucks and compresses the intermediate-pressure refrigerant in the sealed container and discharges it to the oil separation means.

  A refrigeration apparatus according to a ninth aspect of the invention is characterized in that, in the eighth aspect of the invention, the opening degree of the auxiliary throttle means is controlled based on the temperature of the refrigerant sucked into the high-stage compression means from within the sealed container.

  According to a tenth aspect of the present invention, in the refrigeration apparatus invention according to any one of the first to seventh aspects, the compression means is a low-stage compression means housed in a hermetic container together with a drive means constituting the compression means. And the high-stage compression means, the low-stage compression means sucks and compresses the refrigerant that has come out of the evaporator, and combines it with the refrigerant and oil that has come out of the second passage of the internal heat exchanger, While flowing into the sealed container, the high-stage compression means sucks and compresses the intermediate-pressure refrigerant in the sealed container and discharges it to the oil separation means.

  A refrigeration apparatus according to an eleventh aspect of the invention is characterized in that, in the tenth aspect of the invention, the opening degree of the auxiliary throttle means is controlled based on the temperature of the refrigerant flowing into the sealed container.

  A refrigeration apparatus according to a twelfth aspect of the invention is characterized in that carbon dioxide is used as a refrigerant in each of the above inventions.

  According to the present invention, the refrigeration cycle is constituted by the compression means, the radiator, the main throttle means, the evaporator, the auxiliary throttle means, and the internal heat exchanger, the high pressure side becomes the supercritical pressure, and the refrigerant discharged from the radiator Is branched into the first and second refrigerant flows by the refrigerant branching means, and the first refrigerant flow is made to flow through the first passage of the internal heat exchanger, and then is sent from the main throttle means to the evaporator to obtain the second refrigerant. Flow from the auxiliary throttle means to the second passage of the internal heat exchanger, heat exchange is performed between the first refrigerant flow and the second refrigerant flow in the internal heat exchanger, and the refrigerant discharged from the evaporator is In a refrigerating apparatus that sucks into a low-pressure section and sucks refrigerant that has exited from the second passage of the internal heat exchanger into an intermediate-pressure section of the compression means, and separates oil from the refrigerant that is discharged from the compression means and flows into the radiator. Oil separation means is provided and separated by this oil separation means Since the oil is joined to the second refrigerant flow flowing into the auxiliary throttle means by the joining means provided on the inlet side of the auxiliary throttle means, the oil and the refrigerant are cooled by a radiator in which the dissolved state is stable. The oil can be separated in the region of the discharge temperature before being discharged.

  As a result, the oil can be smoothly separated by the oil separation means, and the insufficiency of the oil in the compression means and the inconvenience of the oil falling in the refrigeration cycle can be solved.

  Further, since the oil separated by the oil separation means is joined to the second refrigerant flow flowing into the auxiliary throttle means by the merger provided on the inlet side of the auxiliary throttle means, a special oil return is achieved. Without providing a path, the oil separated by the oil separation means can be returned to the intermediate pressure portion of the compression means together with the second refrigerant flow.

  In the refrigeration apparatus according to the second aspect of the present invention, by providing an oil radiator for cooling the oil separated by the oil separation means in the above invention, the oil separated by the oil separation means can be sufficiently cooled. it can. Thereby, while being able to cool a compression means, deterioration of oil can be suppressed.

  In the refrigeration apparatus according to a third aspect of the present invention, the internal heat exchange is achieved by separating the refrigerant rich in oil by the oil separation means in the second aspect of the invention and allowing the refrigerant rich in oil to flow into the oil radiator. The amount of refrigerant flowing through the second passage of the vessel is increased, and the first refrigerant flow flowing through the first passage can be further cooled.

  In the refrigeration apparatus according to the fourth aspect of the present invention, the oil separating means and / or the heat radiator for oil are integrated with the heat radiator in the second or third aspect of the invention, so that the number of parts can be reduced. it can. Also, the oil cooling performance can be improved.

  In the invention of claim 5, since the throttle means is provided on the outlet side of the oil radiator in the invention of the refrigeration apparatus according to any of claims 2 to 4, the second refrigerant flow from the refrigerant branching means is provided. And the oil pressure from the heat radiator for oil are reduced, and the oil flows too much, whereby the second refrigerant flow is reduced and the disadvantage that the cooling capacity of the internal heat exchanger is reduced can be solved.

  In the refrigeration apparatus according to the sixth aspect of the present invention, since the throttling means is provided between the refrigerant branching means and the merging means in each of the above-described inventions, the pressure of the merging means can be sufficiently reduced as compared with the oil separating means. Even if the pressure loss of the radiator is small or the pressure difference between the oil separating means and the merging means is not sufficient to move the oil to the merging means when the compression means is in a low rotation state, It is possible to reliably guide the oil separated by the separating means to the joining means.

  In the invention of claim 7, since the refrigerant branching means and the merging means are integrally formed in the invention of the refrigeration apparatus according to any one of claims 1 to 5, the number of parts can be reduced.

  In the invention of claim 8, in each of the above inventions, the compression means is composed of a low-stage compression means and a high-stage compression means housed in a hermetic container together with a drive means constituting the compression means. The compression means sucks and compresses the refrigerant discharged from the evaporator, discharges the refrigerant into the sealed container, and the refrigerant and oil output from the second passage of the internal heat exchanger flow into the sealed container, The compression means sucks and compresses the intermediate pressure refrigerant in the sealed container and discharges it to the oil separation means. The refrigerant compressed by the low-stage compression means is mixed with the refrigerant flowing out of the second passage of the internal heat exchanger and flowing into the sealed container, and cooled. At this time, the refrigerant from the second passage of the internal heat exchanger is gasified and only the oil is separated. Thereby, the said oil can be returned to the oil sump in an airtight container.

  The refrigerant in the cooled sealed container is compressed by the high-stage compression means, but the high-stage compression means sucks the cooled refrigerant gas, so that the discharge refrigerant temperature after compression by the high-pressure side compression means is It becomes possible to reduce significantly compared with the case where there is no 2nd refrigerant | coolant flow. Thereby, it is possible to prevent deterioration of oil discharged from the compression means to the outside.

  In the refrigeration apparatus according to the ninth aspect of the present invention, if the opening degree of the auxiliary throttle means is controlled based on the temperature of the refrigerant sucked into the high stage compression means from the inside of the closed container in the eighth aspect of the invention, the driving in the closed container is performed. The intermediate pressure refrigerant temperature sucked into the high-stage compression means after cooling the means can be appropriately controlled by the amount of the second refrigerant flow returned into the sealed container.

  According to a tenth aspect of the present invention, in the refrigeration apparatus invention according to any one of the first to seventh aspects, the compression means is a low-stage compression means housed in a hermetic container together with a drive means constituting the compression means. And the high-stage compression means, the low-stage compression means sucks and compresses the refrigerant that has come out of the evaporator, and combines it with the refrigerant and oil that has come out of the second passage of the internal heat exchanger, If the high pressure side compression means sucks in and compresses the intermediate pressure refrigerant in the closed container and discharges it to the oil separation means, the refrigerant that has flowed out of the second passage is Before entering the sealed container, it merges with the refrigerant discharged from the lower stage compression means and evaporates, and then enters the sealed container and is separated from the oil. As a result, the refrigerant discharged at the intermediate pressure from the low-stage compression means is cooled, and the refrigerant is gasified from the second passage, so that the oil is smoothly returned to the oil reservoir of the sealed container.

  In the refrigeration apparatus according to the eleventh aspect of the present invention, if the opening degree of the auxiliary throttle means is controlled based on the temperature of the refrigerant flowing into the sealed container in the tenth invention, the driving means is cooled by flowing into the sealed container. The intermediate pressure refrigerant temperature can be appropriately controlled by the second refrigerant flow returned to the sealed container.

  Further, even when a carbon dioxide refrigerant having a supercritical pressure on the high pressure side is used in each of the inventions as in the twelfth aspect, the oil can be separated from the refrigerant and returned to the compression means. Thereby, the performance and reliability of the refrigeration apparatus using the carbon dioxide refrigerant can be improved.

  Hereinafter, embodiments of the refrigeration apparatus of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a refrigeration circuit diagram of a refrigeration apparatus according to an embodiment of the present invention, and FIG. 2 is a schematic view of a compressor 1 constituting a part of the refrigeration cycle of FIG. The refrigeration apparatus of the present invention includes a compressor (compression means) 1, a radiator 2, a main expansion valve (main throttle means) 3, an evaporator 4, an auxiliary expansion valve (auxiliary throttle means) 5, and an internal heat exchanger 6. A refrigerant cycle is configured. The compressor 1 includes an electric element 17 as drive means in a horizontal sealed container 16, a first compression element 18 as low-stage compression means driven by a rotating shaft 50 of the electric element 17, It is a compression means which accommodates the 2nd compression element 19 as a stage side compression means. The electric element 17 is provided on one end side of the rotating shaft 50, and the first and second compression elements 18 and 19 are provided on the other end side of the rotating shaft 50. In addition, an oil pump 52 is provided at the other end of the rotary shaft 50, and the suction port of the oil pump 52 is an oil reservoir formed at the bottom of the sealed container 16 (the oil pump 52 side of the sealed container 16). It is open. The oil stored in the oil sump is sucked from the suction port by the oil pump 52 and supplied to the sliding portions of the first and second compression elements 18 and 19.

  One end of a refrigerant introduction pipe 80 is connected to the suction side of the first compression element 18, and low-temperature and low-pressure refrigerant gas is introduced into the first compression element 18 on the lower stage side. The other end of the refrigerant introduction pipe 80 is connected to the outlet of the evaporator 4 outside the compressor 1. Further, one end of the refrigerant introduction pipe 82 is connected to the discharge side of the first compression element 18. The refrigerant introduction pipe 82 extends to the outside of the sealed container 16, and the other end is connected to the sealed container 16 (in the sealed container 16 on the oil pump 52 side). In addition, a refrigerant pipe 90 described later is connected to the midway portion 22 of the refrigerant introduction pipe 82.

  One end of a refrigerant discharge pipe 84 is connected to the discharge side of the second compression element 19, and the high temperature and high pressure compressed by the second compression element 19 on the higher stage side from the refrigerant discharge pipe 84. The refrigerant gas is discharged outside the compressor 1. The other end of the refrigerant discharge pipe 84 is connected to the inlet 103 of the oil separator 10. That is, the compressor 1 sucks and compresses the refrigerant discharged from the evaporator 4 by the first compression element 18, discharges the refrigerant from the refrigerant introduction pipe 82 to the outside of the sealed container 16, and an internal heat exchanger described later. 6, the refrigerant and oil that have come out of the second passage 6 </ b> B are merged in the middle portion 22, and then flown into the sealed container 16, and at the second compression element 19, the intermediate-pressure refrigerant in the sealed container 16 Is sucked in, compressed, and discharged to the oil separator 10.

  The oil separator 10 is oil separating means for separating oil from the refrigerant discharged from the compressor 1 and flowing into the radiator 2. The oil separator 10 is an apparatus for separating oil from a refrigerant by centrifugation as shown in FIG.

  Here, the oil separator 10 will be described with reference to FIG. In FIG. 3, arrows indicate the flow of refrigerant gas and oil in the oil separator 10. The oil separator 10 includes a vertically long cylindrical main body 101 having an oil separation space 102. An inlet 103 communicating with the oil separation space 102 is formed on the side surface of the main body 101. The inlet 103 is formed along the inner wall surface at a position shifted from the axial center of the oil separation space 102. The inlet 103 is connected to the other end of the refrigerant discharge pipe 84 in communication.

  A refrigerant outlet 104 communicating with the oil separation space 102 is formed at a substantially axial center of the upper surface of the main body 101, and a refrigerant pipe 86 is inserted and connected to the refrigerant outlet 104. The refrigerant pipe 86 has a size substantially the same as the diameter of the refrigerant outlet 104 and opens downward (opening 86 </ b> A) in the oil separation space 102. A gap is formed between the inner wall surface of the oil separation space 102 and the outer wall surface of the refrigerant pipe 86 inserted into the oil separation space 102. Similarly, an oil outlet 105 communicating with the oil separation space 102 is formed on the bottom surface of the main body 101.

  Then, the high-temperature and high-pressure refrigerant containing the oil compressed by the compressor 1 is discharged from the inlet 103 of the oil separator 10 toward the inner wall surface in the oil separation space 102, and is centrifuged in the oil separation space 102. The separated refrigerant flows into the refrigerant pipe 86 from the opening 86A in the oil separation space 102 and is discharged to the outside of the oil separator 10. In addition, the oil separated from the refrigerant is discharged from the oil pipe 92 connected to the oil outlet 105 to the outside.

  The refrigerant pipe 86 connected to the refrigerant outlet 104 of the oil separator 10 is connected to the inlet of the radiator 2. The oil pipe 92 connected to the oil outlet 105 of the oil separator 10 is connected to the inlet of the oil radiator 12. The oil radiator 12 is a radiator for cooling the oil separated by the oil separator 10, and the oil radiator 12 of this embodiment is configured integrally with the radiator 2.

  On the other hand, the refrigerant pipe 87 exiting from the radiator 2 is connected to the inlet of the branching device 7. The branching device 7 is a refrigerant branching unit for branching the refrigerant discharged from the radiator 2 into the first and second refrigerant flows, and one outlet of the branching unit 7 is used for the first refrigerant flow. A first refrigerant pipe 8 is connected, and a second refrigerant pipe 9 for the second refrigerant flow is connected to the other outlet.

  The first refrigerant pipe 8 is connected to the first passage 6 </ b> A of the internal heat exchanger 6. The internal heat exchanger 6 exits from the radiator 2 and is branched by the branching device 7, and is branched by the first high-temperature and high-pressure refrigerant flow flowing through the first refrigerant pipe 8 and the branching device 7. 5 for exchanging heat with the second refrigerant flow reduced in pressure, and the first passage 6A and the second passage 6B are arranged to be able to exchange heat. Then, the first refrigerant flow flows through the first passage 6A of the internal heat exchanger 6 and the second refrigerant flow flows through the second passage 6B. In addition, an inlet of the first passage 6A and an outlet of the second passage 6B are formed at one end of the internal heat exchanger 6, and the inlet of the second passage 6B and the second passage are formed at the other end of the internal heat exchanger 6. Each of the outlets of one passage 6A is formed. That is, in the internal heat exchanger 6, the first refrigerant flow that flows through the first passage 6A and the second refrigerant flow that flows through the second passage 6B are counterflows.

  The outlet of the first passage 6 </ b> A formed at the other end of the internal heat exchanger 6 is connected to the main expansion valve 3. The main expansion valve 3 is a main throttle means for reducing the pressure of the first refrigerant flow. A refrigerant pipe 89 exiting the main expansion valve 3 is connected to the inlet of the evaporator 4, and the refrigerant introduction pipe 80 is connected to the outlet of the evaporator 4.

  On the other hand, the piping that exits from the oil radiator 12 is connected to the merger 11. The second refrigerant pipe 9 is also connected to the merger 11. The merger 11 is for joining the oil cooled by the oil radiator 12 and the second refrigerant flow branched by the branching unit 7. Two inlets (an inlet to which a pipe extending from the oil radiator 12 is connected and an inlet to which the second refrigerant pipe 9 is connected) and one outlet are formed. That is, in the merger 11, the oil cooled by the oil radiator 12 and the second refrigerant flow branched by the separator 7 merge. The pipe connected to the outlet of the merger 11 is connected to the auxiliary expansion valve 5. The auxiliary expansion valve 5 is auxiliary throttle means for reducing the pressure of the second refrigerant flow and the oil joined by the merger 11.

  The outlet of the auxiliary expansion valve 5 is connected to the inlet of the second passage 6B formed at the other end of the internal heat exchanger 6, and the outlet of the second passage 6B formed at one end of the internal heat exchanger 6. The refrigerant pipe 90 connected to is connected to the middle part 22 of the refrigerant introduction pipe 82.

  Further, the temperature of the second refrigerant flow and the oil flowing through the refrigerant introduction pipe 82 to the downstream side of the intermediate part 22 to which the refrigerant pipe 90 of the refrigerant introduction pipe 82 is connected and flowing into the sealed container 16 are set. A temperature sensor 21 for detection is installed. The temperature sensor 21 is connected to control means (not shown) that controls the refrigeration apparatus. The control means controls the opening degree of the auxiliary expansion valve 5 based on the refrigerant (refrigerant and oil) temperature detected by the temperature sensor 21.

  Next, the operation of the refrigerating apparatus of this embodiment will be described with reference to the ph diagram (Mollier diagram) of FIG. When the electric element 17 of the compressor 1 is driven by a control means (not shown), the low-temperature and low-pressure (state A in FIG. 4) exits from the evaporator 4 from the refrigerant introduction pipe 80 to the low-pressure chamber side of the first compression element 18. The refrigerant is sucked and compressed. As a result, the refrigerant compressed to the intermediate pressure by the first compression element 18 is discharged from the high-pressure chamber side to the refrigerant introduction pipe 82 (state B in FIG. 4). The intermediate-pressure refrigerant gas discharged to the refrigerant introduction pipe 82 once exits from the sealed container 16, and passes through the second passage 6 </ b> B of the internal heat exchanger 6 from the refrigerant pipe 90 in the middle portion 22 of the refrigerant introduction pipe 82. Merges with the second refrigerant stream and oil that have exited. At this time, the temperature of the refrigerant from the first compression element 18 is lowered by the second refrigerant and oil from the refrigerant pipe 90 (state C in FIG. 4).

  Thereafter, the merged refrigerant and oil flow into the sealed container 16 from the oil pump 52 side. Thereby, the inside of the airtight container 16 becomes an intermediate pressure. Here, the intermediate-pressure refrigerant gas compressed by the first compression element 18 is once discharged to the outside of the sealed container 16 and joined with the second refrigerant flow and the oil that has come out of the internal heat exchanger 6, As described above, the temperature of the refrigerant can be lowered. Thereby, by returning the refrigerant whose temperature has dropped to the hermetic container 16, the compressor 1 that has been overheated by the operation, in particular, the electric element 17 can be cooled.

  Further, the intermediate pressure refrigerant discharged into the sealed container 16 is sucked into the low pressure chamber side of the second compression element 19 and compressed, becomes a high temperature and high pressure refrigerant gas, enters the refrigerant discharge pipe 84 from the high pressure chamber side, It is discharged to the outside of the compressor 1. At this time, the refrigerant is compressed to an appropriate supercritical pressure (state D in FIG. 4).

  The refrigerant gas discharged from the refrigerant discharge pipe 84 is mixed with oil that has been supplied to the sliding portion of the second compression element 19 of the compressor 1. The refrigerant gas and oil are discharged along an inner wall surface in the oil separation space 102 from an inlet 103 formed on one side surface of the main body 101 of the oil separator 10. At this time, the refrigerant gas and the oil are discharged from the inlet 103 along the inner wall surface in the oil separation space 102, whereby the refrigerant gas and the oil mixed in the refrigerant gas are shown in FIG. As shown in FIG. 2, the oil separation space 102 is lowered while spirally passing through a gap formed between the outer wall surface of the refrigerant pipe 86 and the inner wall surface of the oil separation space 102.

  In this process, the oil mixed in the refrigerant gas is centrifuged from the refrigerant gas, adheres to the inner wall surface of the oil separation space 102 and the outer wall surface of the refrigerant pipe 86, travels along the wall surface, and reaches the bottom surface of the oil separation space 102. The oil outlet 105 is formed, enters the oil pipe 92 from there, flows out of the oil separator 10, and flows into the oil radiator 12 formed integrally with the radiator 2.

  Thus, the oil mixed in the refrigerant gas can be separated by centrifuging the oil mixed in the refrigerant gas compressed by the compressor 1 by the oil separator 10.

  On the other hand, the refrigerant separated from the oil by the oil separator 10 enters the refrigerant pipe 86 through the opening 86A of the refrigerant pipe 86 provided in the oil separation space 102, exits the oil separator 10, and then the radiator 2 Flow into. The refrigerant flowing into the radiator 2 is cooled in the radiator 2 by air cooling or water cooling (state E in FIG. 4). Also, the oil that has flowed into the oil radiator 12 formed integrally with the radiator 2 is cooled by an air cooling method or a water cooling method in the process of passing through the oil radiator 12 (like E in FIG. 4). In this state, the oil radiator 12 exits and enters the merger 11.

  The refrigerant cooled by the radiator 2 is discharged to the branching device 7 through the refrigerant pipe 87, and is branched into a first refrigerant flow and a second refrigerant flow here. Then, the first refrigerant flow passes through the first refrigerant pipe 8 connected to one outlet of the branching device 7 and from the inlet of the first passage 6A formed on one end side of the internal heat exchanger 6. Enters the internal heat exchanger 6. The first refrigerant flow on the high-pressure side passes through the first passage 6A of the internal heat exchanger 6, and the low-pressure flowing through the second passage 6B provided in heat exchange with the first passage 6A. Heat is taken away by the second refrigerant flow (second refrigerant flow and oil) on the side (state F in FIG. 4). Thereby, the refrigerant gas of the first refrigerant flow on the high-pressure side flowing through the first passage 6A can be cooled, and the specific enthalpy of the refrigerant at the inlet of the evaporator 4 can be reduced. Thereby, the freezing effect can be increased.

  The first refrigerant flow in the first passage 6 </ b> A cooled by the internal heat exchanger 6 exits the internal heat exchanger 6 from the other end and reaches the main expansion valve 3. Note that the first refrigerant flow is still supercritical at the inlet of the main expansion valve 3. And by the pressure fall in the main expansion valve 3, it will be in the two-phase mixed state of gas and liquid (state G of FIG. 4), and will flow into the evaporator 4 in this state. Here, the first refrigerant flow evaporates by exchanging heat with the surrounding air, and the surrounding air is cooled by the endothermic effect at this time.

  In addition, the first refrigerant flow evaporated in the evaporator 4 (state A in FIG. 4) repeats the cycle of being sucked from the refrigerant introduction pipe 80 into the first compression element 18 on the lower stage side of the compressor 1. .

  On the other hand, the second refrigerant flow branched in the branching device 7 reaches the merger 11 through the second refrigerant pipe 9 connected to the other outlet of the branching device 7. Then, the second refrigerant flow from the second refrigerant pipe 9 and the oil cooled by the oil radiator 12 merge in the merger 11. The merged second refrigerant flow and oil reach the auxiliary expansion valve 5 via a pipe connected to the outlet of the merger 11. Note that the second refrigerant flow is still in a supercritical state at the inlet of the auxiliary expansion valve 5, and the pressure drops in the process of passing through the auxiliary expansion valve 5, resulting in a gas / gas two-phase mixed state (FIG. 4 H state). Then, the second refrigerant flow and oil whose pressure has been reduced by the auxiliary expansion valve 5 flows into the internal heat exchanger 6 from the inlet of the second passage 6B formed at the other end of the internal heat exchanger 6. Expands. At this time, the second refrigerant flow evaporates by taking heat from the refrigerant flowing through the first passage 6A. Thus, the second refrigerant flow can be evaporated by exchanging heat with the high-pressure side refrigerant flowing through the first passage 6A in the internal heat exchanger 6. The evaporated second refrigerant stream and oil on the low-pressure side exits the internal heat exchanger 6 from the outlet at one end, and passes through the refrigerant pipe 90 at the intermediate part 22 of the refrigerant introduction pipe 82. The refrigerant merges with the intermediate-pressure refrigerant flowing in 82 (state C in FIG. 4) and flows into the sealed container 16. The oil that has flowed into the sealed container 16 is separated from the refrigerant and returned to the oil sump formed at the bottom of the sealed container 16. As a result, the oil separated by the oil separator 10 can be cooled and then returned to the sealed container 16.

  In particular, by providing the oil separator 10 before entering the radiator 2, oil mixed in the refrigerant gas can be effectively separated. That is, in the refrigerating apparatus using the carbon dioxide refrigerant and having a high pressure side at the supercritical pressure as in this embodiment, when the oil is separated after cooling by the radiator 2, the refrigerant cooled by the radiator 2 is the refrigerant. Therefore, the oil cannot be smoothly separated from the refrigerant depending on the conditions. As described above, since it is difficult to separate the oil from the refrigerant, the oil cannot be returned to the compressor 1, and the amount of oil in the compressor 1 may decrease, resulting in a shortage of oil.

  In addition, the oil is circulated in the refrigerant cycle, and the oil stagnates in the refrigerant cycle, resulting in problems such as hindering the good flow of the refrigerant and pressure loss, resulting in a decrease in the performance of the refrigeration system. There was a risk of inviting.

  On the other hand, if the oil is separated at the discharge portion of the compressor 1 and directly returned to the sealed container, the oil is returned at a high pressure. Therefore, the fixed throttle mechanism is caused by fluctuations in the rotational speed or high pressure. Cannot cope with fluctuations in differential pressure. Further, as shown in FIG. 15, since the temperature of the oil also returns to a high temperature, the temperature of the sealed container 16 and the electric element 17 of the compressor 1 is increased, which may cause a decrease in efficiency and deterioration of the oil. In addition, the temperature of the entire refrigerant cycle is increased, resulting in a problem that the refrigerating capacity is significantly reduced. In particular, when a refrigerant such as carbon dioxide is used and the high pressure side becomes a high pressure as in this embodiment, the above problem becomes significant.

  However, in the present invention, since the oil separator 10 that separates the oil discharged from the compressor 1 and flowing into the radiator 2 is provided, the oil is separated in the region of the discharge temperature before being cooled by the radiator 2. Can do. In this case, since the dissolved state of the oil and the refrigerant is stable in the discharge temperature region, the amount of the refrigerant dissolved in the oil is small, and therefore, it is suitable for centrifugal separation. Can be separated. Thereby, oil can be smoothly separated by a centrifugal separator having a simple structure without providing a complicated oil separator.

  Further, the oil separated by the oil separator 10 is joined to the second refrigerant flow flowing into the auxiliary expansion valve 5 by the merger 11 provided on the inlet side of the auxiliary expansion valve 5, whereby the oil separator The oil separated at 10 can be returned into the sealed container 16 of the compressor 1 together with the second refrigerant flow. Accordingly, the oil can be easily returned into the sealed container 16 of the compressor 1 without using a special oil return path.

  Further, in this case, since the oil returns to the compressor 1 in a state where the pressure is reduced by the auxiliary expansion valve 5 together with the second refrigerant flow, the problem of the pressure difference as in the prior art can be solved, and the oil can dissipate heat for the oil. Since the temperature is lowered by the second refrigerant flow in addition to the cooling effect in the cooler 12, the temperature of the compressor 1 rises due to the oil return, and the electric element 17 and the compression elements 18 and 19 are damaged. Problems such as oil deterioration can be solved. Furthermore, according to the present invention, it is possible to easily return the oil to the compressor 1 without providing a special oil flow adjustment throttle mechanism due to a pressure difference as in the prior art.

  Moreover, the refrigerant | coolant temperature in the airtight container 16 falls by returning the branched 2nd refrigerant | coolant flow in the airtight container 16 which is an intermediate pressure part of the compressor 1, and the refrigerant | coolant sucked in from the 2nd compression element 19 The specific enthalpy of can be reduced. As a result, it is possible to improve the efficiency of the refrigeration apparatus.

  Further, by providing the oil radiator 12, the separated oil is sufficiently cooled and then merged with the second refrigerant flow in the merger 11, thereby adversely affecting the cooling effect due to the expansion of the second refrigerant flow. The inconvenience can be avoided. Furthermore, the oil radiator 12 can be integrated with the radiator 2 to reduce the number of components and can be integrated with the radiator 2 having a large radiation area to increase the installation space. The oil cooling performance can be improved without inconvenience.

  The opening of the auxiliary expansion valve 5 is controlled by the control means based on the temperature of the second refrigerant flow detected by the temperature sensor 21 provided in the refrigerant introduction pipe 82. That is, when the temperature of the refrigerant detected by the temperature sensor 21 is higher than a predetermined temperature set in advance, the opening of the auxiliary expansion valve 5 is increased (throttle is reduced). This increases the flow rate of the second refrigerant flow. That is, since the amount of the second refrigerant flow that merges with the refrigerant compressed by the first compression element 18 in the middle portion 22 of the refrigerant introduction pipe 82 increases, the temperature of the refrigerant flowing into the sealed container 16 is further increased. Can be lowered.

  On the other hand, when the temperature of the refrigerant detected by the temperature sensor 21 is lower than a predetermined temperature set in advance, the opening of the auxiliary expansion valve 5 is decreased (throttle is expanded). This reduces the flow rate of the second refrigerant flow. That is, since the amount of the second refrigerant flow that merges with the refrigerant compressed by the first compression element 18 at the midway portion 22 of the refrigerant introduction pipe 82 decreases, the temperature of the refrigerant flowing into the sealed container 16 is raised. be able to. In this way, by controlling the throttle of the auxiliary expansion valve 5 based on the refrigerant temperature detected by the temperature sensor 21, the flow into the sealed container 16 is caused by the amount of the second refrigerant flow returned to the sealed container 16. Thus, the temperature of the intermediate-pressure refrigerant that cools the electric element 17 can be appropriately controlled.

  As described in detail above, the refrigeration apparatus of the present invention reduces the compression power of the compressor 1 to improve the coefficient of performance, and effectively separates the oil mixed in the refrigerant discharged from the compressor 1. be able to. As a result, it is possible to improve the performance and reliability of the refrigeration apparatus, in particular, improve the performance and reliability of the refrigeration apparatus using the carbon dioxide refrigerant.

  The oil separation means used in the refrigeration apparatus of the present invention is not limited to the oil separator 10 shown in the first embodiment, and any oil separation means can be used as long as it can perform oil separation. Absent. In this case, an oil separator 110 as shown in FIG. 5 can be used. FIG. 5 is a view showing an oil separator 110 as oil separation means of another embodiment. In FIG. 5, the oil separator 110 is also a device for separating the refrigerant and the oil by centrifugation as in the above embodiment. In addition, the arrow shown in FIG. 5 has shown the flow of the refrigerant | coolant and oil. In the oil separator 110, an oil separation space 112 is configured in a main body 111 having a horizontally long cylindrical shape, and a horizontally long cylindrical inlet portion 113 communicating with the oil separation space 112 is formed at one end of the main body 111. The other end of the refrigerant discharge pipe 84 is connected to the tip opening 113A of the inlet 113.

  In addition, a spiral paddle is formed on the inner wall surface of the inlet 113, and the refrigerant entering the inlet 113 from the refrigerant discharge pipe 84 and the oil mixed in the refrigerant create a swirling flow by the paddle. ing. In addition, a refrigerant outlet 114 communicating with the oil separation space 112 is formed at the other end of the main body 111, and an oil outlet 115 communicating similarly with the oil separation space 112 is formed at the bottom surface of the main body 111.

  The refrigerant pipe 86 connected to the refrigerant outlet 114 of the oil separator 110 is connected to the inlet of the radiator 2. Further, the oil pipe 92 connected to the oil outlet 115 is connected to the inlet of the oil radiator 12 as in the above embodiment.

  Here, the flow of the refrigerant and oil in the oil separator 110 will be described. In the present embodiment, the same reference numerals as those in the previous embodiment have the same or similar effects and will not be described. First, the supercritical refrigerant that has been compressed by the second compression element 19 to a high temperature and high pressure flows from the refrigerant discharge pipe 84 into the oil separator 110 through the tip opening 113A of the inlet 113. The refrigerant gas and the oil mixed in the refrigerant gas are swirled by the paddle of the inlet portion 113 and flow into the main body 111 in this state. At this time, the swirling refrigerant and oil discharged into the oil separation space 112 advances toward the refrigerant outlet 114 while spirally swirling within the oil separation space 112.

  In this process, the oil mixed in the refrigerant gas is centrifuged from the refrigerant gas, adheres to the wall surface of the oil separation space 102, travels along this wall surface, reaches the oil outlet 115 formed on the bottom surface, and from there As in the example, the oil pipe 92 is entered.

  On the other hand, the refrigerant gas from which the oil has been separated enters the refrigerant pipe 86 from the refrigerant outlet 114 and is discharged from the oil separator 110. As described above, even when the oil separator 110 of this embodiment is used, the oil in the refrigerant gas can be effectively separated as in the above embodiment.

  In the first embodiment, the structure of the radiator 2 was not specifically described. However, the radiator 2 of the first embodiment has the radiator 2 and the oil radiator 12 integrally formed. Anything can be used. In addition to the structure of the above embodiment, the oil separating means (oil separator) and the oil radiator may be formed integrally with the radiator. The heat radiator in this case will be described with reference to FIGS. FIG. 6 is an external view showing the radiator of this embodiment, and FIG. 7 is an internal configuration diagram of the radiator of FIG.

  The radiator 120 of the present embodiment is a microtube type heat exchanger composed of a header (an inlet header 121 and an outlet header 122) and a plurality of microtubes (not shown). The radiator 120 is integrally formed with an oil separator 130 as oil separating means.

  That is, the radiator 120 passes through each microtube, a plurality of microtubes attached to a plurality of fins (not shown), an inlet header 121 that is formed at one end of these microtubes and distributes the refrigerant to each microtube. An outlet header 122 for joining the refrigerant, an oil separator 130 installed on the opposite side of the inlet header 121 from the microtube, and an oil separator 140 provided below the microtube. The The oil radiator 140 includes an oil passage 141 disposed in contact with a plurality of fins attached to the microtube of the radiator 120. In FIGS. 6 and 7, the same reference numerals as those in the above-described embodiments are used, and the description thereof is omitted because they have the same or similar effects.

  Next, the flow of the refrigerant and oil in the radiator 120 of this embodiment will be described with reference to FIGS. 6 and 7. First, the refrigerant compressed in the compressor 1 and having a high temperature and high pressure is discharged from the refrigerant discharge pipe 84, and the inlet 103 formed on one side surface of the main body 101 of the oil separator 130 formed integrally with the radiator 120. To the wall surface in the oil separation space 102. At this time, the refrigerant discharged into the oil separation space 102 and the oil mixed in the refrigerant gas are discharged from the outer wall surface of the refrigerant pipe 86 and the inside of the oil separation space 102 as indicated by arrows in FIG. The oil separation space 102 is lowered while spiraling around the gap formed between the wall surface.

  In this process, the oil mixed in the refrigerant gas is centrifuged from the refrigerant gas, adheres to the inner wall surface of the oil separation space 102 and the outer wall surface of the refrigerant pipe 86, and travels along these wall surfaces to the bottom surface of the oil separation space 102. It flows into the oil radiator 140 formed. On the other hand, the refrigerant from which the oil has been separated enters the refrigerant pipe 86 through the opening 86A of the refrigerant pipe 86 provided in the oil separation space 102, exits the oil separator 130, and flows into the inlet header 121 from the upper end side. .

  The refrigerant gas that has flowed into the inlet header 121 is diverted and enters each microtube (not shown), and is cooled by air cooling or water cooling in the process of passing through the microtube. Similarly, the oil flowing into the oil radiator 140 is cooled in the process of passing through the piping 141 provided in contact with the fins of the radiator 120. Thereafter, the oil radiator 140 is extracted from the oil pipe 92 connected to the other end, and enters the merger 11 as in the above embodiments.

  In addition, the refrigerant cooled after passing through each microtube is merged with the refrigerant that has flowed through each microtube at the outlet header 122, and then discharged from the refrigerant pipe 87 connected to the outlet header 122 to the outside of the radiator 120. Is done.

  In this way, by configuring the oil separator 130 and the oil radiator 140 integrally with the radiator 120, the number of components can be further reduced.

  In each of the above embodiments, the refrigerant gas and the oil mixed in the refrigerant gas are separated by the oil separation means (oil separator). However, the invention is not limited to the one that separates only the oil. First, for example, a refrigerant containing a large amount of oil is separated from a refrigerant flowing into the radiator by an oil separator, and the refrigerant containing a large amount of oil is cooled by a radiator for oil. It may be combined with a flow and a combiner. FIG. 8 is an internal configuration diagram of an embodiment of the radiator 150 in the present embodiment. In FIG. 8, the same reference numerals as those in the above-described embodiments are used, and the description thereof is omitted because they have the same or similar effects.

  In this case, the oil separator 130 separates the refrigerant gas and the oil-rich refrigerant, but the oil-rich refrigerant has a larger amount than the oil alone as in the above embodiments. Therefore, it is necessary to increase the capacity of the oil radiator 140. Therefore, the area of the oil pipe 141 of the oil radiator 140 is increased so that the refrigerant containing a large amount of oil flowing through the oil radiator 140 can dissipate more heat. On the other hand, since the amount of refrigerant flowing through the radiator 120 is reduced by that amount, the refrigerant can be sufficiently dissipated even if the capacity is made smaller than that of the above embodiment. Therefore, in this embodiment, as shown in FIG. 8, the heat dissipating area of the radiator 120 is made smaller than that of the above embodiment, and the heat dissipating area of the oil radiator 140 is made larger.

  Thereby, the refrigerant | coolant containing many oils which flows through the heat radiator 140 for oil can be cooled effectively. In this case, the refrigerant containing a large amount of oil cooled by the oil radiator 140 joins the second refrigerant flow in the merger 11, and is then throttled by the auxiliary expansion valve 5, and then passes through the internal heat exchanger 6. And flows into the sealed container 16. As described above, since it is not necessary to strictly separate the oil from the refrigerant by the oil separator 130, the oil separator 130 can be simplified and reduced in cost. Further, since the amount of the refrigerant flowing into the second passage 6B increases, the first refrigerant flow flowing through the first passage 6A provided in heat exchange with the second passage 6B can be further cooled. Further, the refrigerant returned to the hermetic container 16 of the compressor 1 can be further cooled. Therefore, according to the present embodiment, the cooling of the first refrigerant flow can further contribute to the cooling of the compressor 1 after being returned to the compressor 1.

  Next, another embodiment of the refrigeration apparatus of the present invention will be described with reference to FIGS. FIG. 9 is a refrigerant circuit diagram of a refrigerating apparatus according to another embodiment of the present invention, and FIG. 10 is an internal configuration diagram of the compressor of the refrigerating apparatus of FIG. In FIGS. 9 and 10, the same reference numerals as those shown in FIGS. 1 to 8 are used, and the description thereof is omitted because they have the same or similar effects.

  In FIG. 9, reference numeral 14 denotes a throttle means provided between the branching device 7 and the merger 11, and a capillary tube or the like is used as the throttle means. The capillary tube 14 is a throttle means provided to lower the pressure of the merger 11 and guide the oil separated by the oil separator 10 to the merger 11. That is, when the pressure loss of the radiator 2 is small or the compressor 200 is operated at a low speed and the pressure difference between the oil separator 10 and the merger 11 is not sufficient to move the oil to the merger. The oil may not flow smoothly into the merger 11. For this reason, as in this embodiment, a capillary tube 14 is provided between the branching device 7 and the merger 11, and the pressure of the second refrigerant flow entering the merger 11 is lowered, so that the oil separator 10 and the merger are merged. The oil separator 10 is high between the separator 11 and the merger 11 can constitute a low pressure difference, and the oil separated by the oil separator 10 can be reliably guided to the merger 11. It becomes possible.

  Here, as shown in FIG. 10, the compressor 200 described above includes an electric element 17 as a driving means in a horizontal sealed container 16 and a low-stage compression means driven by a rotating shaft 50 of the electric element 17. And a second compression element 19 serving as a high-stage side compression means. The electric element 17 is provided on one end side of the rotating shaft 50, and the first and second compression elements 18 and 19 are provided on the other end side of the rotating shaft 50. An oil pump 52 is provided at the other end of the rotating shaft 50, and the suction port of the oil pump 52 is opened by an oil reservoir formed at the bottom of the sealed container 16. With the oil pump 52, the oil stored in the oil sump can be sucked from the suction port and supplied to the sliding portions of the first and second compression elements 18, 19.

  One end of a refrigerant introduction pipe 80 is connected to the suction side of the first compression element 18, and a low-temperature and low-pressure refrigerant gas is introduced into the first compression element 18 on the lower stage side from here. The other end of the refrigerant introduction pipe 80 is connected to the outlet of the evaporator 4 outside the compressor 1. The discharge side of the first compression element 18 and the oil pump 52 side opposite to the electric element 17 in the sealed container 16 are communicated with each other. That is, the intermediate-pressure refrigerant compressed by the first compression element 18 is discharged to the side where the oil pump 52 opposite to the electric element 17 in the sealed container 16 is provided.

  In addition, the oil pump 52 side and the electric element 17 side in the sealed container 16 are communicated with each other through a hole 201 penetrating the first and second compression elements 18. Then, one end of the refrigerant introduction pipe 82 is connected to the suction side of the second compression element 19. The refrigerant introduction pipe 82 passes through the outside of the sealed container 16 from one end connected to the suction side of the second compression element 19, and the other end communicates with the inside of the sealed container 16 near the electric element 17. In addition, a temperature sensor 121 for detecting an intermediate pressure refrigerant temperature sucked into the second compression element 19 on the higher stage side from the sealed container 16 is provided in the middle of the refrigerant introduction pipe 82. The temperature sensor 121 is connected to a control means (not shown) that controls the refrigeration apparatus. The control means controls the opening of the auxiliary expansion valve 5 based on the refrigerant temperature detected by the temperature sensor 121.

  Reference numeral 90 is a refrigerant pipe having one end connected to the outlet of the second passage 6B of the internal heat exchanger 6, and the other end of the refrigerant pipe 90 is an oil pump 52 in the hermetic container 16 as shown in FIG. It communicates with the side. And the 2nd refrigerant | coolant flow and oil which evaporated in the 2nd channel | path 6B of the internal heat exchanger 6 from the said refrigerant | coolant piping 90 flow in into the airtight container 16 which is an intermediate pressure part of the compressor 1. FIG.

  The operation of the refrigeration apparatus of the present embodiment will be described with the above configuration. When the electric element 17 of the compressor 200 is driven by a control means (not shown), the low-temperature and low-pressure refrigerant discharged from the evaporator 4 is sucked from the refrigerant introduction pipe 80 into the low-pressure chamber side of the first compression element 18 and compressed. The As a result, the refrigerant compressed to the intermediate pressure by the first compression element 18 is discharged from the high pressure chamber side to the oil pump 52 side (the side opposite to the electric element 17) in the sealed container 16. Then, the discharged refrigerant passes through the hole 201 penetrating the first and second compression elements 18 and 19 and is discharged to the electric element 17 side in the sealed container 16. Thereby, the inside of the airtight container 16 becomes an intermediate pressure. The intermediate-pressure refrigerant gas discharged to the electric element 17 side in the sealed container 16 passes through the outside of the sealed container 16 from the other end of the refrigerant introduction pipe 82 connected to the sealed container 16 on the electric element 17 side. 2 is sucked into the low-pressure chamber side of the compression element 19 and compressed to become high-temperature and high-pressure refrigerant gas, enters the refrigerant discharge pipe 84 from the high-pressure chamber side, and is discharged to the outside of the compressor 1. At this time, the refrigerant is compressed to an appropriate supercritical pressure.

  In the refrigerant gas discharged from the refrigerant discharge pipe 84, the oil supplied to the sliding portion of the second compression element 19 of the compressor 1 is mixed. The refrigerant gas and oil are discharged from an inlet 103 formed on one side surface of the main body 101 of the oil separator 10 toward a wall surface in the oil separation space 102. At this time, the refrigerant gas discharged into the oil separation space 102 and the oil mixed in the refrigerant gas are formed between the outer wall surface of the refrigerant pipe 86 and the inner wall surface of the oil separation space 102 due to the momentum at the time of discharge. The oil separation space 102 is lowered while spiraling around the gap.

  In this process, the oil mixed in the refrigerant gas is centrifuged from the refrigerant gas, adheres to the inner wall surface of the oil separation space 102 and the outer wall surface of the refrigerant pipe 86, and travels along these wall surfaces to the bottom surface of the oil separation space 102. The oil outlet 105 is formed, enters the oil pipe 92 from there, flows out of the oil separator 10, and flows into the oil radiator 12 formed integrally with the radiator 2.

  Thus, the oil mixed in the refrigerant gas can be separated by centrifuging the oil mixed in the refrigerant gas compressed by the compressor 1 by the oil separator 10.

  On the other hand, the refrigerant separated from the oil by the oil separator 10 enters the refrigerant pipe 86 through the opening 86A of the refrigerant pipe 86 provided in the oil separation space 102, exits the oil separator 10, and then the radiator 2 Flow into. The refrigerant flowing into the radiator 2 is cooled in the radiator 2 by air cooling or water cooling. In addition, the oil that has flowed into the oil radiator 12 formed integrally with the radiator 2 is cooled by air or water cooling in the process of passing through the oil radiator 12 in the same manner as the refrigerant. Exit the radiator 12 and enter the merger 11. At this time, the oil separated by the oil separator 10 is smoothly flown to the oil radiator 12 due to the pressure difference between the oil separator 10 using the capillary tube 14 and the low pressure difference, and cooled there. Then, it moves to the merger 11.

  The refrigerant cooled by the radiator 2 is discharged to the branching device 7 through the refrigerant pipe 87, and is branched into a first refrigerant flow and a second refrigerant flow here. Then, the first refrigerant flow passes through the first refrigerant pipe 8 connected to one outlet of the branching device 7 and from the inlet of the first passage 6A formed on one end side of the internal heat exchanger 6. Enters the internal heat exchanger 6. The first refrigerant flow on the high pressure side flows through the second passage 6B provided in heat exchange with the first passage 6A in the process of passing through the first passage 6A of the internal heat exchanger 6. Heat exchange with the second refrigerant stream (second refrigerant stream and oil). Thereby, the refrigerant | coolant of the 1st refrigerant | coolant flow of the high voltage | pressure side which flows through 6 A of 1st passages can be cooled, and the specific enthalpy of the refrigerant | coolant in the evaporator 4 inlet_port | entrance can be made small. Thereby, the freezing effect can be increased.

  The first refrigerant flow in the first passage 6 </ b> A cooled by the internal heat exchanger 6 exits the internal heat exchanger 6 from the other end and reaches the main expansion valve 3. Note that the first refrigerant flow is still supercritical at the inlet of the main expansion valve 3. And by the pressure drop in the main expansion valve 3, it will be in the two-phase mixed state of gas and liquid, and will flow into the evaporator 4 in this state. Here, the first refrigerant flow evaporates by exchanging heat with the surrounding air, and the surrounding air is cooled by the endothermic effect at this time.

  In addition, the first refrigerant flow evaporated in the evaporator 4 repeats a cycle of being sucked into the first compression element 18 on the lower stage side of the compressor 1 from the refrigerant introduction pipe 80.

  On the other hand, the second refrigerant flow enters the second refrigerant pipe 9 connected to the other outlet of the branching device 7 and is depressurized by the capillary tube 14. In this way, the pressure of the second refrigerant flow entering the merger 11 can be reduced by reducing the pressure of the second refrigerant flow in the capillary tube 14. That is, the pressure in the merger 11 can be lowered by the second refrigerant flow. As a result, the oil separated by the oil separator 10 as described above can be reliably guided to the merger 11.

  The refrigerant depressurized by the capillary tube 14 merges with the oil cooled by the merger 11 and the oil radiator 12. Then, the merged second refrigerant flow and oil reach the auxiliary expansion valve 5 via a pipe connected to the outlet of the merger 11 and drop in pressure in the process of passing through the auxiliary expansion valve 5. Then, the second refrigerant flow and oil whose pressure has been reduced by the auxiliary expansion valve 5 flows into the internal heat exchanger 6 from the inlet of the second passage 6B formed at the other end of the internal heat exchanger 6. The refrigerant expands in the process of flowing through the second passage 6B, and evaporates by taking heat from the refrigerant flowing through the first passage 6A. Thus, the second refrigerant flow can be evaporated by exchanging heat with the high-pressure refrigerant flowing through the first passage 6A in the internal heat exchanger 6.

  The vaporized second refrigerant flow and oil on the low pressure side exits the internal heat exchanger 6 from the outlet at one end, flows into the oil pump 52 side in the sealed container 16 via the refrigerant pipe 90, The refrigerant compressed with the first compression element 18 and mixed with the refrigerant compressed with the first compression element 18 is cooled. At this time, the second refrigerant flow is gasified, only the oil is separated, and can be returned to the oil reservoir formed at the bottom of the closed casing 16 on the oil pump 52 side. Thereby, after the oil separated in the oil separator 10 is cooled, it can be returned to the oil pump 52 side in the sealed container 16. As described above, the refrigerant can be effectively returned to the vicinity of the oil pump 52 by connecting the refrigerant pipe 90 to the oil pump 52 side of the sealed container 16.

  Here, by returning the second refrigerant flow and oil that have come out of the internal heat exchanger 6 into the sealed container 16, the compressor 1 that has been overheated by operation can be cooled. Then, the second refrigerant flow that has flowed into the oil pump 52 in the sealed container 16 is compressed by the first compression element 18, and the intermediate-pressure refrigerant gas discharged to the oil pump 52 in the sealed container 16. And then discharged through the hole 201 to the electric element 17 side in the sealed container 16. Thereby, the electric element 17 can be cooled by the second refrigerant flow. In addition, the refrigerant on the electric element 17 side is sucked into the second compression element 19 through the refrigerant introduction pipe 82 and compressed, but the second compression element 19 is cooled by the cooling effect of the second refrigerant flow described above. The compressed refrigerant temperature after compression at is greatly reduced compared to the case where there is no second refrigerant flow.

  Therefore, an increase in the discharge temperature of the refrigerant and oil discharged from the compressor 1 can be suppressed, and deterioration of the oil discharged from the compressor 1 can be prevented.

  The opening of the auxiliary expansion valve 5 is controlled by the control means based on the refrigerant temperature detected by the temperature sensor 121 provided in the refrigerant introduction pipe 82. That is, when the temperature of the refrigerant detected by the temperature sensor 121 is higher than a predetermined temperature set in advance, the opening of the auxiliary expansion valve 5 is increased (throttle is reduced). This increases the flow rate of the second refrigerant flow. That is, since the second refrigerant flow returning in the sealed container 16 increases, the temperature of the refrigerant flowing into the sealed container 16 can be further lowered.

  On the other hand, when the temperature of the refrigerant detected by the temperature sensor 121 is lower than a predetermined temperature set in advance, the opening of the auxiliary expansion valve 5 is decreased (throttle is expanded). This reduces the flow rate of the second refrigerant flow. That is, since the amount of the second refrigerant flow that returns in the sealed container 16 decreases, the temperature of the refrigerant flowing into the sealed container 16 can be increased. Thus, by controlling the throttle of the auxiliary expansion valve 5 based on the refrigerant temperature detected by the temperature sensor 121, the second compression element 19 is controlled by the amount of the second refrigerant flow returned to the sealed container 16. It becomes possible to appropriately control the temperature of the intermediate-pressure refrigerant sucked into the refrigerant.

  As described in detail above, also in the refrigeration apparatus of the present embodiment, the compression power of the compressor 200 is reduced to improve the coefficient of performance and the refrigerant discharged from the compressor 200 is reduced as in the above embodiments. The mixed oil can be effectively separated. As a result, it is possible to improve the performance and reliability of the refrigeration apparatus, in particular, improve the performance and reliability of the refrigeration apparatus using the carbon dioxide refrigerant.

  In the fifth embodiment, the capillary tube 14 as the throttle means is provided between the branching device 7 and the merger 11, but the throttle means is provided on the outlet side of the oil radiator 12 as shown in FIG. It may be provided. In this case, the pressure of the second refrigerant flow from the branching device 7 and the oil pressure from the oil radiator 12 is reduced by squeezing the oil cooled by the oil radiator 12 with the capillary tube 13 as a throttle means. The amount of the oil separated by the oil separator 10 and the second refrigerant flow can be adjusted to a predetermined amount.

  This reliably eliminates the disadvantage that the amount of oil that merges with the second refrigerant flow is too large, the second refrigerant flow decreases, and the ability to cool the first refrigerant flow in the internal heat exchanger 6 decreases. become able to.

  Further, in each of the above embodiments, the branching device 7 as the refrigerant branching unit and the junction unit 11 as the refrigerant merging unit are configured as separate members. However, the refrigerant branching unit and the refrigerant merging unit are configured integrally. It doesn't matter. 12 and 13 show an example of this case. 12 and 13, reference numeral 15 denotes a branching / merging device in which the refrigerant branching means and the refrigerant joining means are integrally formed. In FIGS. 12 and 13, the same reference numerals as those in FIGS. 1 to 11 denote the same or similar effects, and the description thereof is omitted.

  The branching / merging device 15 is provided with a partition member 15B that vertically separates the inside of the container body 15A into an upper space and a lower space, and the partition member 15B is formed with a hole 15C that communicates the upper and lower spaces. The hole 15C functions as one outlet of the refrigerant branching means. Further, an inlet 15D communicating with the upper space is formed on one side surface of the container main body 15A, and the refrigerant radiated by the radiator 2 flows from the inlet 15D. The other outlet 15E of the refrigerant branching means is formed at a position substantially symmetrical to the inlet 15D. An inlet 15F communicating with the lower space is formed below the inlet 15D, and an outlet 15G is formed at the bottom of the container body 15A.

  A refrigerant pipe 87 that connects the radiator 2 and the upper space of the branching / merging device 15 is connected to the inlet 15D. The outlet 15E is connected to the first refrigerant pipe 8 for the first refrigerant flow, and the inlet 15F is connected to the branching / merging device 15 that communicates the oil radiator 12 and the lower space of the container body 15A. A pipe 95 communicating with the lower space is connected. Furthermore, a second refrigerant pipe 9 for the second refrigerant flow is connected to the bottom outlet 15G.

  Here, the operation of the refrigerant and oil in the branching / merging device 15 will be described. That is, the refrigerant gas radiated by the radiator 2 enters the upper space of the container main body 15A of the branch merging device 15 from the inlet 15D through the refrigerant pipe 87, and the refrigerant gas is branched into two branches in the space. One first refrigerant flow flows into the first refrigerant pipe 9 connected to the outlet 15 </ b> E and exits from the branching / merging device 15.

  On the other hand, the other second refrigerant flow branched in the upper space of the container main body 15A of the branching / merging device 15 enters the lower space of the container main body 15A through the hole 15C. The oil radiated by the oil radiator 12 enters the lower space of the container main body 15A of the branching / merging device 15 from the inlet 15F through the pipe 95. As a result, the second refrigerant flow branched in the upper space of the container main body 15A of the branching / merging device 15 and the oil radiated by the oil radiator 12 merge in the lower space of the container main body 15A. The second refrigerant flow and oil thus entered enter the second refrigerant pipe 9 connected to the outlet 15G and exit from the branching / merging device 15.

  As described above, the branching / merging device 15 of the present embodiment makes it possible to integrally form the refrigerant branching means and the refrigerant joining means, thereby reducing the number of parts.

  FIG. 14 is a refrigerant circuit diagram of still another refrigeration apparatus. The refrigerant cycle shown in FIG. 14 is provided with another internal heat exchanger 160 in addition to the internal heat exchanger 6 described in the above embodiments. The internal heat exchanger 160 exchanges heat between the high-pressure side first refrigerant flow exiting from the first passage 6A of the internal heat exchanger 6 and the low-pressure side first refrigerant flow exiting from the evaporator 4. The refrigerant pipe 160A on the high-pressure side and the refrigerant pipe 160B on the low-pressure side are installed in a heat exchange manner.

  The internal heat exchanger 160 can further cool the high-pressure side first refrigerant flow cooled by the internal heat exchanger 6, and can reduce the specific enthalpy of the refrigerant at the inlet of the evaporator 4. Thereby, the freezing effect can be further increased. Furthermore, the refrigerant on the low pressure side evaporated in the evaporator 4 may not be completely in the form of gas but liquid may remain, but the first refrigerant on the high pressure side in the process of passing through the internal heat exchanger 160. By exchanging heat with the flow, it can be completely gasified. As a result, even when the gas-liquid separator 190 is not installed on the outlet side of the evaporator 4, the occurrence of liquid compression in which the liquid refrigerant is sucked into the compressor 1 is eliminated and the performance and reliability are further improved. Can be improved.

It is a refrigerant circuit figure of the refrigerating device of one example of the present invention. Example 1 It is an internal block diagram of the compressor of the freezing apparatus of FIG. It is a figure which shows the oil separator of the freezing apparatus of FIG. FIG. 2 is a Mollier diagram of the refrigeration apparatus of FIG. 1. It is a figure which shows the oil separator of another Example. (Example 2) It is an external view of the heat radiator of another Example. Example 3 It is an internal block diagram of the heat radiator of FIG. It is an internal block diagram of the heat radiator of another Example. Example 4 It is a refrigerant circuit diagram of the refrigerating apparatus of another Example. (Example 5) It is an internal block diagram of the compressor of the freezing apparatus of FIG. It is a refrigerant circuit diagram of the freezing apparatus of another Example. (Example 6) It is a refrigerant circuit figure of the refrigerating apparatus of another another Example. (Example 7) It is an enlarged view of the branch merger of the freezing apparatus of FIG. It is a refrigerant circuit figure of the refrigerating device of another another Example. (Example 8) It is the Mollier diagram of the conventional freezing apparatus.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Compressor 2,120,150 Radiator 3 Main expansion valve 4 Evaporator 5 Auxiliary expansion valve 6 Internal heat exchanger 6A 1st channel | path 6B 2nd channel | path 7 Branch device 8 1st refrigerant | coolant piping 9 2nd refrigerant | coolant Piping 10, 110, 130 Oil separator 11 Merger 12, 140 Oil radiator 13, 14 Capillary tube 15 Branch merger 16 Sealed container 17 Electric element 18 First compression element 19 Second compression element 21, 121 Temperature Sensor 22 Middle part 50 Rotating shaft 52 Oil pump 80, 82 Refrigerant introduction pipe 84 Refrigerant discharge pipe 86 Refrigerant pipe 90 Refrigerant pipe 92 Oil pipe 101, 111 Main body 102, 112 Oil separation space 103 Inlet 104, 105, 114, 115 Outlet 113 Entrance

Claims (12)

The refrigeration cycle is composed of the compression means, the radiator, the main throttle means, the evaporator, the auxiliary throttle means, and the internal heat exchanger, the high pressure side becomes the supercritical pressure, and the refrigerant discharged from the radiator is cooled by the refrigerant branching means. The first refrigerant flow is branched into first and second refrigerant flows, and the first refrigerant flow is caused to flow through the first passage of the internal heat exchanger, and then is caused to flow from the main throttle means to the evaporator, and the second refrigerant flow. Flow from the auxiliary throttle means to the second passage of the internal heat exchanger, causing the first refrigerant flow and the second refrigerant flow to exchange heat in the internal heat exchanger and exiting the evaporator In the refrigeration apparatus, the refrigerant is sucked into the low pressure part of the compression means, and the refrigerant discharged from the second passage of the internal heat exchanger is sucked into the intermediate pressure part of the compression means,
Oil separation means for separating oil from the refrigerant discharged from the compression means and flowing into the radiator is provided, and the oil separated by the oil separation means is joined by a joining means provided on the inlet side of the auxiliary throttle means A refrigeration apparatus characterized in that it is joined to the second refrigerant flow flowing into the auxiliary throttle means.   The refrigeration apparatus according to claim 1, further comprising an oil radiator for cooling the oil separated by the oil separation means.   The refrigeration apparatus according to claim 2, wherein the oil separation means separates a refrigerant containing a large amount of oil, and causes the refrigerant containing a large amount of oil to flow into the oil radiator.   4. The refrigeration apparatus according to claim 2, wherein the oil separation unit and / or the oil radiator is integrated with the radiator. 5.   The refrigerating apparatus according to any one of claims 2 to 4, wherein a throttle means is provided on an outlet side of the oil radiator.   The refrigerating apparatus according to any one of claims 1 to 5, wherein a throttle means is provided between the refrigerant branching means and the merging means.   The refrigerating apparatus according to any one of claims 1 to 5, wherein the refrigerant branching unit and the merging unit are integrally formed.   The compression means is composed of a low-stage compression means and a high-stage compression means housed in a hermetic container together with a drive means constituting the compression means, and the low-stage compression means comes out of the evaporator. Refrigerant is sucked and compressed, discharged into the sealed container, and the refrigerant and oil exiting from the second passage of the internal heat exchanger flow into the sealed container, and the high-stage compression means includes the The refrigeration apparatus according to any one of claims 1 to 7, wherein the refrigerant having an intermediate pressure in the sealed container is sucked in and compressed and discharged to the oil separation means.   9. The refrigeration apparatus according to claim 8, wherein the opening degree of the auxiliary throttle means is controlled based on the temperature of the refrigerant sucked into the high-stage compression means from within the sealed container.   The compression means is composed of a low-stage compression means and a high-stage compression means housed in a hermetic container together with a drive means constituting the compression means, and the low-stage compression means comes out of the evaporator. The refrigerant is sucked in and compressed, merged with the refrigerant and oil that have come out of the second passage of the internal heat exchanger, and then flowed into the sealed container. The refrigerant | coolant of any one of Claim 1 thru | or 7 which sucks and compresses the refrigerant | coolant of the intermediate pressure of this, and discharges it to the said oil separation means.   The refrigerating apparatus according to claim 10, wherein the opening degree of the auxiliary throttle means is controlled based on the temperature of the refrigerant flowing into the sealed container.   The refrigeration apparatus according to any one of claims 1 to 11, wherein carbon dioxide is used as the refrigerant.

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