JP5934931B2 - Tank for refrigeration cycle apparatus and refrigeration cycle apparatus including the same - Google Patents

Description

  The present invention relates to a tank for a refrigeration cycle apparatus used in a refrigeration cycle apparatus having a refrigerant circuit composed of a compressor, a gas cooler (heat radiator), a throttle means, an evaporator, and the like, and a refrigeration cycle apparatus including the same. is there.

  Conventionally, this kind of refrigeration cycle apparatus has a refrigerant circuit composed of a compressor, a gas cooler, a throttle means, an evaporator, etc., and the refrigerant compressed by the compressor dissipates heat in the gas cooler and is depressurized by the throttle means, and then the evaporator Then, the refrigerant is evaporated and the ambient air is cooled by the evaporation of the refrigerant at this time. In recent years, in this type of refrigeration cycle apparatus, it has become impossible to use chlorofluorocarbon refrigerants due to natural environmental problems and the like. For this reason, the thing using the carbon dioxide which is a natural refrigerant | coolant is developed as a substitute of a fluorocarbon refrigerant | coolant. It is known that the carbon dioxide refrigerant is a refrigerant having a high and low pressure difference, has a low critical pressure, and a high pressure side of the refrigerant cycle is brought into a supercritical state by compression.

  The chlorofluorocarbon refrigerant described above enters the receiver tank after exiting the condenser, and is temporarily stored therein to separate the gas and liquid. The separated liquid refrigerant is stored in the receiver tank, and is used for adjusting the refrigerant amount according to the outside air temperature and the like.

  On the other hand, when a refrigerant such as carbon dioxide that has a supercritical pressure on the high pressure side is used, a saturation cycle is performed when the outside air temperature falls, so that the refrigerant is in a liquid / gas mixed state and a receiver provided on the low pressure side. Gas and liquid are separated by the tank, and only the gas refrigerant is sucked into the compressor. The amount of circulating refrigerant in the refrigerant circuit can also be adjusted by the receiver tank. However, when the outside air temperature rises and becomes, for example, + 25 ° C. to 30 ° C. or more, the refrigerant is not liquefied and the gas cycle operation is performed. Therefore, the amount of circulating refrigerant cannot be adjusted by the receiver tank, and there is a problem that the high-pressure side pressure abnormally increases due to excessive gas refrigerant in the refrigerant circuit.

  When a refrigerant amount adjustment tank is installed on the high pressure side of the refrigerant circuit and the refrigerant in the refrigerant circuit becomes excessive due to an increase in the outside air temperature, etc., the refrigerant is collected in the refrigerant amount adjustment tank according to the increase in pressure on the high pressure side. When the pressure on the high pressure side decreases due to a decrease in the outside air temperature, a method of releasing the refrigerant from the refrigerant amount adjustment tank into the refrigerant circuit has been considered (for example, see Patent Document 1).

JP 2011-133204 A

  In addition to the recovery pipe (inflow pipe) for allowing the refrigerant to flow at the time of recovery and the discharge pipe for allowing the refrigerant to flow at the time of discharge, the refrigerant amount adjustment tank as described above can be used for the pressure ( An outflow pipe for allowing the gas refrigerant) to escape into the refrigerant circuit for smooth recovery must be attached to the tank body.

  In this case, in order to ensure the liquid level in the tank body, the recovery pipe is attached to the upper part of the tank body, and the outflow pipe is also connected to the upper part of the tank body to release the gas refrigerant for pressure relief in the tank body. Will be attached. 4 and 5 show a schematic structure of such a conventional refrigerant quantity adjustment tank 100. FIG. 101 is the tank body having a predetermined capacity, 102 is the recovery pipe (inflow pipe), 103 is the discharge pipe, and 104 is the outflow pipe. All are attached to the attachment holes drilled in the tank body 101 and fixed by welding. Liquid refrigerant or liquid / gas mixed refrigerant passes through the recovery pipe 102 and flows into the tank body 101. The gas refrigerant in the upper part of the tank body 101 passes through the outflow pipe 104 and flows out of the tank body 101. The discharge pipe 103 is attached to the bottom surface of the tank main body 101, and the liquid refrigerant in the tank main body 101 passes through and flows out from the tank main body 101.

  If only the outflow pipe 104 is attached to the upper wall of the tank main body 101 and the recovery pipe 102 is attached to the side wall of the tank main body 101 as in the case of FIG. 4, the strength of the tank main body 101 is extremely reduced. In addition, since the liquid level (liquid refrigerant) in the tank main body 101 is regulated by the height of the recovery pipe 102, the height or diameter of the tank main body 101 must be enlarged to ensure the capacity.

  Therefore, as shown in FIG. 5, if two mounting holes are formed in the upper wall of the tank main body 101 and the outflow pipe 104 and the recovery pipe 102 are fixed by welding, the strength of the upper part of the tank main body 101 will be extremely high. Therefore, there is a problem that it is necessary to increase the thickness of the tank body 101, particularly when used in a refrigeration cycle apparatus using carbon dioxide, which has extremely high pressure in the refrigerant circuit. .

  The present invention has been made to solve the conventional technical problems, and is formed by welding and fixing a refrigerant inflow pipe and an outflow pipe to a tank body, and improves the strength of a tank used in a refrigeration cycle apparatus. The present invention provides a structure that can be maintained without increasing the thickness.

In order to solve the above problems, a tank for a refrigeration cycle apparatus according to the present invention includes a tank body having a predetermined capacity for storing refrigerant in a liquid state, a liquid / gas mixed state, or a gas state , and a refrigerant flowing into the tank body. A tank used in a refrigeration cycle device, wherein the inflow pipe and the outflow pipe constitute a double pipe. The double pipe is welded and fixed to an attachment hole formed in the upper wall of the tank body, and the end of the outflow pipe is attached to the attachment hole, and the end of the inflow pipe is flush with the attachment hole, Alternatively, the inflow pipe and the outflow pipe are opened in the same space in the tank body, and are located inside the tank body from the mounting hole .

  A tank for a refrigeration cycle apparatus according to a second aspect of the present invention is a double pipe in which at least a part of the outflow pipe is constituted by a T-shaped pipe and the inflow pipe is inserted into the outflow pipe with a space therebetween. It is characterized by comprising.

A refrigeration cycle apparatus according to a third aspect of the invention includes the tank for the refrigeration cycle apparatus according to the first or second aspect.

A refrigeration cycle apparatus according to a fourth aspect of the invention is characterized in that in the above invention, carbon dioxide is used as a refrigerant.

  According to the present invention, a tank body having a predetermined capacity, an inflow pipe through which a refrigerant flowing into the tank body passes, and an outflow pipe through which a refrigerant flowing out of the tank body passes are used in a refrigeration cycle apparatus. In the tank for the refrigeration cycle, a double pipe is constituted by the inflow pipe and the outflow pipe, and the double pipe is welded and fixed to the mounting hole formed in the upper wall of the tank body. It is not necessary to form a plurality of layers, and it is possible to prevent a decrease in strength.

  This makes it possible to reduce the thickness of the tank body and eliminate the need for capacity expansion. Also, by reducing the number of parts, it is easy to share parts.

  In this case, if at least a part of the outflow pipe is configured with a T-shaped pipe as in the invention of claim 2 and the double pipe is configured by inserting and arranging the inflow pipe with a space in the outflow pipe, The structure of the double pipe is also simplified.

  Further, the end portion of the outflow pipe is attached to the mounting hole as in the invention of claim 3, and the end portion of the inflow pipe is flush with the mounting hole or inside the tank body from the mounting hole, thereby The inconvenience of the refrigerant flowing directly into the outflow pipe can also be prevented.

  In particular, the present invention is effective in the refrigeration cycle apparatus of the invention of claim 4 using carbon dioxide as the refrigerant of the invention of claim 5.

It is a refrigerant circuit figure of the refrigerating cycle device to which the present invention is applied. It is a vertical side view of the refrigerant | coolant amount adjustment tank which is an Example of the tank for refrigeration cycle apparatuses of this invention. It is a principal part enlarged view of the refrigerant | coolant amount adjustment tank of FIG. It is a vertical side view of the conventional refrigerant quantity adjustment tank. It is a vertical side view of another conventional refrigerant quantity adjustment tank.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a refrigerant circuit diagram of a refrigeration cycle apparatus R according to an embodiment to which the present invention is applied. The refrigeration cycle apparatus R in this embodiment includes a refrigerator 3 and one or a plurality of showcases 4, and these refrigerators 3 and the showcase 4 are connected to a refrigerant through a unit outlet 6 and a unit inlet 7. A predetermined refrigerant circuit 1 is configured by being connected by pipes 8 and 9.

  The refrigerant circuit 1 uses, as a refrigerant, carbon dioxide whose refrigerant pressure (high pressure) on the high pressure side is equal to or higher than the critical pressure (supercritical). This carbon dioxide refrigerant is a natural refrigerant that is friendly to the global environment and takes into consideration flammability and toxicity. As the lubricating oil, existing oils such as mineral oil (mineral oil), alkylbenzene oil, ether oil, ester oil, and PAG (polyalkyl glycol) are used.

  The refrigerator 3 includes a compressor 11. In this embodiment, the compressor 11 is a multistage compression rotary compressor, and includes a cylindrical sealed container 12 made of a steel plate, and an electric element 13 as a drive element disposed and housed in the upper part of the internal space of the sealed container 12; A first (low-stage side) rotary compression element (first compression element) 14 and a second (high-stage side) rotary compression element (which are arranged below the electric element 13 and are driven by the rotating shaft ( The second compression element) 16 is constituted by a rotary compression mechanism section.

  The first rotary compression element 14 of the compressor 11 compresses the low-pressure refrigerant sucked into the compressor 11 from the low-pressure side of the refrigerant circuit 1 via the refrigerant pipe 9, boosts it to an intermediate pressure, and discharges it. The element 16 further sucks in the intermediate pressure refrigerant compressed and discharged by the first rotary compression element 14, compresses it to a high pressure, and discharges it to the high pressure side of the refrigerant circuit 1. The compressor 11 is a variable frequency compressor, and the rotational frequency of the first rotary compression element 14 and the second rotary compression element 16 can be controlled by changing the operating frequency of the electric element 13.

  On the side surface of the sealed container 12 of the compressor 11, a low-stage suction port 17 communicating with the first rotary compression element 14, a low-stage discharge port 18 communicating with the inside of the sealed container 12, and a second rotary compression element. A high-stage suction port 19 and a high-stage discharge port 21 communicating with 16 are formed. A refrigerant introduction pipe 22 is connected to the low-stage suction port 17 of the compressor 11 and is connected to the refrigerant pipe 9.

  The low pressure (LP: about 4 MPa in the normal operation state) refrigerant gas sucked into the low pressure portion of the first rotary compression element 14 by the low stage side suction port 17 is caused to generate an intermediate pressure (MP The pressure is increased to about 8 MPa in a normal operation state and discharged into the sealed container 12. Thereby, the inside of the airtight container 12 becomes an intermediate pressure (MP).

  An intermediate pressure discharge pipe 23 is connected to the low-stage discharge port 18 of the compressor 11 through which the intermediate pressure refrigerant gas in the sealed container 12 is discharged, and is connected to one end of the intercooler 24. The intercooler 24 air-cools the intermediate pressure refrigerant discharged from the first rotary compression element 14, and an intermediate pressure suction pipe 26 is connected to the other end of the intercooler 24. The suction pipe 26 is connected to the high stage side suction port 19 of the compressor 11.

  The medium-pressure (MP) refrigerant gas sucked into the second rotary compression element 16 by the high-stage side suction port 19 is compressed by the second stage by the second rotary compression element 16, and the high-temperature high-pressure (HP : Supercritical pressure of about 12 MPa in a normal operation state).

  A high-pressure discharge pipe 27 is connected to the high-stage discharge port 21 provided on the high-pressure chamber side of the second rotary compression element 16 of the compressor 11, and a gas cooler (heat radiator) 28, a split constituting a split cycle. The refrigerant pipe 8 is connected via a heat exchanger (intermediate heat exchanger) 29 or the like.

  The gas cooler 28 cools the high-pressure discharged refrigerant discharged from the compressor 11, and a gas cooler blower 31 that air-cools the gas cooler 28 is disposed in the vicinity of the gas cooler 28. In the present embodiment, the gas cooler 28 is juxtaposed with the intercooler 24 described above, and these are disposed in the same air passage.

  On the other hand, the showcase 4 is installed in a store such as a supermarket or a convenience store, and is connected to the refrigerant pipes 8 and 9. The showcase 4 is provided with a throttle means (electric expansion valve or the like) 32 and an evaporator 33, and is sequentially connected between the refrigerant pipe 8 and the refrigerant pipe 9 (the throttle means 32 is on the refrigerant pipe 8 side). The evaporator 33 is the refrigerant pipe 9 side). The evaporator 33 is provided with an unshown cool air circulation blower that blows air to the evaporator 33. The refrigerant pipe 9 is connected to the low-stage suction port 17 that communicates with the first rotary compression element 14 of the compressor 11 via the refrigerant introduction pipe 22 as described above. Thereby, the refrigerant circuit 1 of the refrigerating cycle apparatus R in a present Example is comprised.

  The refrigeration cycle apparatus R includes a control device (control means) (not shown) configured by a general-purpose microcomputer. In the control device, various sensors are connected to the input side, and various valve devices including electric expansion valves and electromagnetic valves described later, the compressor 11, the gas cooler blower 31, and the like are connected to the output side. Shall. In the figure, 34 and 36 are strainers. Reference numeral 37 denotes a check valve having a forward direction on the compressor 11 side, and is interposed in the refrigerant introduction pipe 22.

  In addition, the refrigerant circuit 1 of the refrigeration cycle apparatus R of the embodiment is a split cycle, and serves as a merging apparatus that merges the first rotary compression element (low stage side) 14 of the compressor 11, the intercooler 24, and the two fluid flows. , The second rotary compression element (high stage side) 16 of the compressor 11, the gas cooler 28, the split heat exchanger 29, the flow divider 42, the auxiliary throttle means (auxiliary electric expansion valve) 43, the main throttle means (main An electric expansion valve) 32 and an evaporator 33.

  The flow divider 42 is a flow dividing device that branches the refrigerant from the split heat exchanger 29 into two flows. That is, the flow divider 42 of the present embodiment diverts the refrigerant from the split heat exchanger 29 into the first refrigerant flow and the second refrigerant flow, and flows the first refrigerant flow to the auxiliary circuit. The refrigerant flow is configured to flow through the main circuit.

  The main circuit in FIG. 1 includes the first rotary compression element 14, the intercooler 24, the merger 41, the second rotary compression element 16, the gas cooler 28, the second flow path 29B of the split heat exchanger 29, and the strainer 34. , An annular refrigerant circuit comprising a flow divider 42, a main throttle means 32, an evaporator 33, a strainer 36, and a check valve 37, and the auxiliary circuit includes the flow divider 42, the auxiliary throttle means 43 and the split heat exchanger 29 It is a circuit that reaches the merger 41 through the first flow path 29A sequentially.

  The auxiliary throttle means 43 is for diverting the first refrigerant flow that is diverted by the flow divider 42 and flows through the auxiliary circuit. The split heat exchanger 29 is a heat exchanger that performs heat exchange between the first refrigerant flow in the auxiliary circuit decompressed by the auxiliary throttle means 43 and the second refrigerant flow that has exited from the gas cooler 28. In the split heat exchanger 29, a second flow path 29B through which the second refrigerant flow flows and a first flow path 29A through which the first refrigerant flow flows are provided in a heat exchangeable relationship. Since the second refrigerant flow is cooled by the first refrigerant flow flowing through the first flow path 29A by passing through the second flow path 29B of the split heat exchanger 29, the ratio in the evaporator 33 is reduced. It is comprised so that enthalpy can be made small. The main throttle means 32 and the auxiliary throttle means 43 are controlled to an appropriate value by the control device described above, and an efficient operation is realized.

  Further, in the present embodiment, on the high pressure side, which is the supercritical pressure of the refrigerant circuit 1, on the downstream side of the split heat exchanger 29 and the flow divider 42 of the refrigerator 3, the first communication circuit 51 is used for the present invention. A refrigerant amount adjusting tank 52 as an embodiment of the tank is connected. The refrigerant amount adjustment tank 52 is composed of a tank main body 53 having a predetermined volume, and a recovery pipe 54 as an inflow pipe to which the first communication circuit 51 is connected is attached to the upper wall of the tank main body 53. ing. The detailed structure of the refrigerant quantity adjustment tank 52 will be described in detail later.

  The first communication circuit 51 is provided with an electric expansion valve 56 as a first opening / closing means having an opening degree adjusting function in order to adjust the refrigerant recovery amount. The opening / closing means having the opening adjustment function is not limited to this, and for example, the first communication circuit 51 may be constituted by a capillary tube and an electromagnetic valve (opening / closing valve) as a throttle means.

  In addition, an outflow pipe 57 is attached to the upper wall of the tank body 53 in the refrigerant amount adjustment tank 52. A second communication circuit 58 that connects the upper part in the tank main body 53 and the intermediate pressure region of the refrigerant circuit 1 is connected to the outflow pipe 57. In the present embodiment, the other end of the second communication circuit 58 is communicated with the intermediate pressure suction pipe 26 on the outlet side of the intercooler 24 of the refrigerant circuit 1 as an example of the intermediate pressure region. The second communication circuit 58 is provided with an electromagnetic valve 59 as a second opening / closing means.

  A discharge pipe 61 is attached to the lower surface of the tank main body 53 of the refrigerant amount adjustment tank 52. The discharge pipe 61 is connected to a third communication circuit 62 that communicates the lower portion of the tank body 53 with the intermediate pressure region of the refrigerant circuit 1. In the present embodiment, the other end of the third communication circuit 62 is connected to the downstream side of the auxiliary throttle means 43 as an example of the intermediate pressure region, and finally the intermediate pressure on the outlet side of the intercooler 24 of the refrigerant circuit 1. The suction pipe 26 is communicated. The third communication circuit 62 is provided with an electromagnetic valve 63 and a capillary tube (throttle means) 64 as third opening / closing means.

  The control device includes a unit outlet-side pressure sensor 66 that detects the pressure at the unit outlet 6. Whether the detected pressure of the sensor 66 exceeds a predetermined recovery threshold value, or the unit outlet-side pressure. It is determined whether or not the detected pressure of the sensor 66 exceeds a predetermined recovery protection value lower than the previous recovery threshold value, and the rotational speed of the gas cooler blower 24 is at a maximum value.

  In this embodiment, the intermediate pressure (MP) of the refrigerant circuit 1 has an appropriate value of about 8 MPa as an example. Therefore, the value is set as a recovery protection value, and the recovery threshold is higher than the recovery protection value (for example, 9 MPa) Set to. Moreover, the maximum value of the rotation speed of the gas cooler blower 24 in this embodiment is set to 800 rpm as an example. Further, it may be a condition that a predetermined time elapses after the rotation number of the gas cooler blower 24 reaches the maximum value.

  Thereby, the control device exceeds the recovery protection value of 8 MPa when the detected pressure of the unit outlet side pressure sensor 66 exceeds the recovery threshold of 9 MPa, or even if the detected pressure is equal to or lower than the recovery threshold, and When the rotation speed of the gas cooler blower 24 is the maximum value of 800 rpm, it is determined that the high-pressure side pressure has abnormally increased due to excessive gas refrigerant in the refrigerant circuit 1, and the refrigerant recovery operation is executed. .

  In this refrigerant recovery operation, the control device opens the electric expansion valve (first opening / closing means) 56 and the electromagnetic valve (second opening / closing means) 59 with the electromagnetic valve (third opening / closing means) 63 closed. To do. As a result, the high-temperature and high-pressure refrigerant discharged from the high-stage discharge port 21 of the compressor 11 is cooled by the gas cooler 28 and the split heat exchanger 29 and then partially (liquid state or liquid / gas mixed state). Alternatively, the refrigerant passes through the first communication circuit 51 and the recovery pipe 54 provided with the electric expansion valve 56 in which the refrigerant in the gas state is opened, and flows into the tank body 53 of the refrigerant amount adjustment tank 52.

  At this time, since the electromagnetic valve 59 is opened, the upper part in the tank body 53 of the refrigerant amount adjusting tank 52 and the intermediate pressure region of the refrigerant circuit 1 are communicated via the second communication circuit 58. As a result, the gas refrigerant in the upper part of the tank body 52 passes through the outflow pipe 57 and the second communication circuit 58 and flows out of the tank body 52, so that the pressure can be released out of the tank body 52.

  Therefore, even when the gas cycle operation in which the refrigerant in the refrigerant circuit 1 does not liquefy, such as when the outside air temperature becomes high, the pressure in the tank main body 53 decreases and flows into the tank main body 53. The refrigerant liquefies and accumulates in the tank body 53. That is, when the pressure in the refrigerant amount adjustment tank 52 drops below the supercritical pressure, the refrigerant changes from the gas region to the saturation region, and the liquid level can be secured.

  As a result, the refrigerant in the refrigerant circuit 1 can be quickly and efficiently collected in the tank body 53 of the refrigerant amount adjustment tank 52. Therefore, it is possible to eliminate the disadvantage that the refrigerant circuit 1 has an excessively high pressure on the high-pressure side, and to prevent the compressor 11 from being overloaded due to a high-pressure abnormality.

  In particular, unlike the case where the upper part in the tank body 53 of the refrigerant amount adjusting tank 52 and the intermediate pressure region of the refrigerant circuit 1 are communicated with each other via the second communication circuit 58, the refrigerant circuit 1 is communicated with the low pressure side region. It is possible to avoid a decrease in cooling efficiency due to an increase in the low-pressure side pressure.

  On the other hand, the control device determines whether or not the pressure on the high pressure side detected by the unit outlet side pressure sensor 66 has become a recovery protection value, which is 8 MPa or less in this embodiment. The refrigerant recovery operation is terminated and the operation proceeds to the refrigerant holding operation. In this refrigerant holding operation, the control device maintains a state where the electromagnetic valve (third opening / closing means) 63 is closed, closes the electromagnetic valve (second opening / closing means) 59, and operates the electric expansion valve (first opening / closing means). ) Maintain the opening of 56 in the refrigerant recovery operation.

  The opening degree of the electric expansion valve 562 may be smaller than the opening degree in the refrigerant recovery operation. As a result, the liquid level in the tank body 53 of the refrigerant amount adjusting tank 52 is maintained by the pressure by the high pressure side region of the refrigerant circuit 1 through the opened electric expansion valve 56 by closing the electromagnetic valve 59. Is possible. Therefore, liquid sealing in the refrigerant quantity adjustment tank 52 can be avoided, and safety can be ensured. Thereby, it becomes possible to maintain the amount of circulating refrigerant in the refrigerant circuit 1 appropriately.

  In addition, the control device makes the opening of the electric expansion valve 56 in the refrigerant holding operation smaller than the opening in the refrigerant recovery operation, so that the refrigerant amount adjustment tank 52 in the refrigerant circuit 1 is included in the refrigerant holding operation. When the refrigerant is recovered excessively, it is possible to effectively eliminate the disadvantage that the refrigerant shortage in the refrigerant circuit 1 occurs.

  Then, the control device detects when the pressure detected by the unit outlet side pressure sensor 66 falls below a predetermined release threshold (in this embodiment, about 7 MPa) lower than the recovery protection value (in this case, about 8 MPa), or the unit It is determined whether or not the detected pressure of the outlet side pressure sensor 66 is equal to or lower than the previous recovery protection value and the rotational speed of the gas cooler blower 24 is equal to or lower than a predetermined specified value lower than the maximum value. In this embodiment, the predetermined specified value is about 3/8 of the maximum value, that is, about 300 rpm when the maximum value is 800 rpm. Moreover, it is good also as a condition that predetermined time passes, after the rotation speed of the fan 24 for gas coolers becomes below a predetermined regulation value.

  As a result, the control device detects that the detected pressure of the unit outlet side pressure sensor 66 is below the discharge threshold value of 7 MPa, or the detected pressure is 8 MPa or less which is the recovery protection value, and the rotation of the gas cooler blower 24 When the number is a predetermined specified value, in this case 300 rpm or less, it is determined that the refrigerant in the refrigerant circuit 1 has become insufficient, and the refrigerant discharge operation is executed.

  In this refrigerant discharge operation, the control device closes the electric expansion valve (first opening / closing means) 56 and the electromagnetic valve (second opening / closing means) 59 and opens the electromagnetic valve (third opening / closing means) 63. As a result, the liquid refrigerant accumulated in the tank body 53 of the refrigerant quantity adjustment tank 52 flows out through the discharge pipe 61 connected to the lower part of the tank body 53, and the electromagnetic valve 63 is opened. The refrigerant circuit 1 discharges the refrigerant through the communication circuit 62. Therefore, unlike the case where the gas refrigerant is mixed from the upper part of the refrigerant quantity adjustment tank 52 and discharged to the refrigerant circuit 1, the refrigerant in the tank body 53 of the refrigerant quantity adjustment tank 52 can be quickly released to the refrigerant circuit 1. As a result, the refrigeration apparatus can be operated with high efficiency.

  Note that the second or third communication circuit 58, 52 connected to the intermediate pressure region of the refrigerant circuit 1 on the outlet side of the intercooler 24 of the refrigeration cycle apparatus R, in this embodiment, connected to the outlet side of the intercooler 24. And a bypass circuit 71 that communicates with the refrigerant introduction pipe 22 in the low pressure side of the refrigerant circuit 1, in this embodiment. The bypass circuit 71 is provided with an electromagnetic valve 72 that is opened when the compressor 11 is started to improve startability.

  Next, the detailed structure of the refrigerant quantity adjusting tank 52 will be described in detail with reference to FIGS. 2 is a longitudinal sectional view showing a specific structure of the refrigerant quantity adjustment tank 52 schematically shown in FIG. 1, and FIG. 3 is an enlarged view of the upper part of the refrigerant quantity adjustment tank 52 of FIG. As described above, the recovery pipe (inflow pipe) 54 and the outflow pipe 57 are attached to the upper wall 53A of the tank body 53 of the refrigerant quantity adjustment tank 52. The recovery pipe 54 and the outflow pipe 57 constitute a double pipe. doing.

  In this case, the outflow pipe 57 is a double pipe outer pipe, and the recovery pipe 54 is a double pipe inner pipe. The outflow pipe 57 includes upper and lower connection pipes 73 and 74, a T-shaped pipe 76 positioned therebetween, and a horizontal connection pipe 77. The T-shaped tube 76 is used in such a state that both end openings 76A and 76B of the T-shaped arm portion are in the vertical direction, and the opening 76C of the T-shaped foot portion is lateral, and the upper connecting tube 73 is connected to the opening 76A. The lower end portion of the lower connecting pipe 74 is inserted into the opening 76B and fixed by welding. Further, the lateral connection pipe 77 is inserted into the opening 76C and fixed by welding.

  The recovery pipe 54 is inserted from the upper end of the upper connection pipe 73 into the outflow pipe 57 with a gap, passes through the T-shaped pipe 76 and the lower connection pipe 74, and the lower end thereof is the lower end of the lower connection pipe 74. Is located below. In this state, the upper end portion of the recovery pipe 54 extends upward from the upper end portion of the upper connection pipe 73, and the upper end portion of the upper connection pipe 73 is squeezed so that the inner surface thereof is in close contact with the outer surface of the recovery pipe 54, and is fixed by welding. Has been sealed. As a result, the recovery pipe 54 is held in the outflow pipe 57 with a space therebetween to form a double pipe.

  The recovery pipe 54 and the outflow pipe 57 thus made into a double pipe are inserted into a mounting hole 78 drilled in the upper wall 53A of the tank body 53, and the lower connection pipe 74 and the tank of the outflow pipe 57. The main body 53 is welded and fixed. Thereby, the refrigerant quantity adjusting tank 52 is completed.

  In this state, the lower end of the lower connection pipe 74 of the outflow pipe 57 is flush with the lower edge of the mounting hole 78 formed in the upper wall 53A of the tank main body 53, opens into the tank main body 53 and communicates therewith, and is recovered. The pipe 54 extends into the tank body 53 that is lower than the lower edge of the mounting hole 78 of the tank body 53 by a predetermined dimension, and opens into the tank body 53 to communicate therewith. Note that the lower end of the recovery pipe 54 may also be flush with the lower edge of the mounting hole 78 of the tank main body 53 and may not be positioned above the lower edge of the mounting hole 78.

  The recovery pipe 54 is connected to the first communication circuit 51, the horizontal connection pipe 77 is connected to the second communication circuit 58, and the discharge pipe 61 is connected to the third communication circuit 62. In the refrigerant recovery operation described above, the inside of the recovery pipe 54 (inside the inner pipe of the double pipe) in which the refrigerant in the liquid state, the liquid / gas mixed state, or the gas state is the inner pipe of the double pipe. It passes through and flows into the tank body 53 of the refrigerant quantity adjustment tank 52 from the lower end opening (solid arrow in FIG. 3).

  On the other hand, the gas refrigerant in the upper part of the tank body 52 is located between the lower connection pipe 74 and the recovery pipe 54 from the lower end opening of the lower connection pipe 74 of the outflow pipe 57 that is an outer pipe of the double pipe (inner pipe of the double pipe). Outside the pipe and into the outer pipe), passes between the recovery pipe 54, the lower connecting pipe 74 and the T-shaped pipe 76 and enters the horizontal connecting pipe 77 (the upper connecting pipe 73 is sealed). Therefore, it flows out to the second communication circuit 58 (broken arrow in FIG. 3).

  In this way, the recovery pipe (inflow pipe) 54 and the outflow pipe 57 of the refrigerant amount adjustment tank 52 constitute a double pipe, and this double pipe is inserted into the mounting hole 78 formed in the upper wall 53A of the tank body 53. By welding and fixing, it is not necessary to form a plurality of mounting holes in the upper wall 63A of the tank main body 53, and it is possible to prevent a decrease in strength. As a result, the tank body 53 can be made thinner and the capacity need not be increased. This is particularly effective in the refrigeration cycle apparatus R that uses carbon dioxide as a refrigerant. Also, by reducing the number of parts, it is easy to share parts.

  Further, since the outflow pipe 57 is constituted by the upper and lower connecting pipes 73 and 74 and the T-shaped pipe 76 and the recovery pipe 54 is inserted and arranged in the outflow pipe 57 with a space therebetween, a double pipe is formed. The structure of the double pipe is also simplified.

  Furthermore, the lower end portion of the lower connection pipe 74 of the outflow pipe 57 is attached to the attachment hole 78, and the lower end of the recovery pipe 54 is flush with the attachment hole 78 or inside the tank body 53 from the attachment hole 78. The inconvenience that the refrigerant flows directly from the recovery pipe 54 into the lower connection pipe 74 of the outflow pipe 57 can also be prevented.

  In the above-described embodiment, the present invention is applied to the refrigerant amount adjustment tank 52 in the refrigeration cycle apparatus R. However, the present invention is not limited to this, and the gas-liquid (refrigerant) is connected to the low pressure side of the refrigerant circuit 1 (the suction side of the compressor 11). It is also effective to apply the present invention to a receiver tank or the like that performs the separation.

  In this case, the pipe 54 in FIG. 3 is connected to the outlet side of the evaporator 33 of the refrigerant circuit 1, and the pipe 57 is connected to the refrigerant introduction pipe 22 of the compressor 11.

R Refrigeration cycle apparatus 1 Refrigerant circuit 3 Refrigerator 3 Showcase 8, 9 Refrigerant piping 11 Compressor 24 Intercooler 28 Gas cooler 31 Gas cooler blower 33 Evaporator 51 First communication circuit 52 Refrigerant amount adjustment tank 53 Tank body 54 Recovery piping ( Inflow piping)
57 Outflow pipe 58 Second communication circuit 61 Release pipe 62 Third communication circuit 73, 74 Vertical connection pipe 76 T-shaped pipe 78 Mounting hole

Claims (4)

A tank body having a predetermined capacity for storing refrigerant in a liquid state, a liquid / gas mixed state or a gas state, an inflow pipe through which the refrigerant flowing into the tank body passes, and an outflow through which the refrigerant flowing out of the tank body passes A tank for use in a refrigeration cycle apparatus,
The inflow pipe and the outflow pipe constitute a double pipe, and the double pipe is welded and fixed to an attachment hole formed in the upper wall of the tank body,
Attach the end of the outflow pipe to the mounting hole, the end of the inflow pipe is flush with the mounting hole, or located inside the tank body from the mounting hole,
The tank for a refrigeration cycle apparatus, wherein the inflow pipe and the outflow pipe are open to the same space in the tank body .   2. The double pipe is configured by configuring at least a part of the outflow pipe with a T-shaped pipe and inserting and arranging the inflow pipe with a gap in the outflow pipe. A tank for a refrigeration cycle apparatus according to 1. A refrigeration cycle apparatus comprising the tank for the refrigeration cycle apparatus according to claim 1. The refrigeration cycle apparatus according to claim 3 , wherein carbon dioxide is used as the refrigerant.

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