Turbo compressor and turbo refrigerator provided with same

Abstract

This turbo compressor is provided with: an impeller; a shaft portion that rotates the impeller; an electric motor that rotationally drives the shaft part; a housing accommodating the electric motor; a magnetic bearing that supports the shaft part; one surface of the heat transfer plate is mounted on the outer surface of the shell; a magnetic bearing driving substrate in surface contact with the other surface of the heat transfer plate on the side opposite to the one surface; and a cooling unit that transmits cold and heat of the supplied refrigerant to the heat transfer plate by supplying the refrigerant from the outside.

Description

Technical Field

[0001] The present invention relates to a turbo compressor and a turbo refrigerator having the turbo compressor.

[0002] This application claims priority based on patent application No. 2022-125214 filed in Japan on August 5, 2022, and the contents are incorporated herein by reference. Background Art

[0003] For example, Patent Document 1 discloses a turbo compressor having a magnetic bearing drive substrate for driving a magnetic bearing supporting a shaft portion. The magnetic bearing drive substrate is mounted on a housing of the turbo compressor. The housing is cooled by guiding a cooling refrigerant into the housing, and as a result, the magnetic bearing drive substrate is cooled.

[0004] Previous technical literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2021-156220 Summary of the invention

[0007] Technical issues to be solved by the invention

[0008] Therefore, the housing described in the above-mentioned patent document 1 is made of a metal such as an aluminum alloy, and the housing functions as a heat sink for cooling the magnetic bearing drive substrate. In order to cool the magnetic bearing drive substrate, when the entire housing is formed of a metal such as an aluminum alloy, the cost may increase, for example, compared with the case where the housing is formed of a metal material such as iron. In addition, the temperature of the housing may change depending on the load on the turbo compressor, and the heat generation of the magnetic bearing drive substrate may change, so it is not easy to cool stably.

[0009] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a turbo compressor and a turbo refrigerator that can stably cool a magnetic bearing drive substrate while suppressing an increase in cost.

[0010] Means for solving technical problems

[0011] In order to solve the above-mentioned problems, the turbo compressor involved in the present invention comprises: an impeller; a shaft portion that rotates the impeller; an electric motor that drives the shaft portion to rotate; a housing that accommodates the electric motor; a magnetic bearing that supports the shaft portion; a heat transfer plate, one side of which is mounted on the outer surface of the housing;

[0012] a magnetic bearing driving substrate in surface contact with the other surface of the heat transfer plate opposite to the one surface; and a cooling unit that transfers heat of the supplied refrigerant to the heat transfer plate by supplying the refrigerant from the outside.

[0013] The turbo refrigerator involved in the present invention comprises: the above-mentioned turbo compressor; a condenser that condenses the refrigerant discharged from the turbo compressor; an expansion valve that expands the refrigerant condensed in the condenser; an evaporator that evaporates the refrigerant adiabatically expanded in the expansion valve; and a refrigerant supply unit that can guide the refrigerant condensed in the condenser to the cooling unit.

[0014] Effects of the Invention

[0015] According to the present invention, it is possible to provide a turbo compressor and a turbo refrigerator that can stably cool a magnetic bearing drive substrate while suppressing an increase in cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a system diagram for explaining the structure of the turbo refrigerator according to the embodiment of the present invention.

[0017] Figure 2 It means from Figure 1 A diagram showing the structure of the casing and the cooling unit when observing the turbo compressor in the direction of line II-II.

[0018] Figure 3 It means from Figure 2 A diagram showing the structure of the groove portion when one side of the heat transfer plate is observed in the direction of line III-III. DETAILED DESCRIPTION

[0019] Hereinafter, a mode for implementing a turbo refrigerator including a turbo compressor according to the present invention will be described with reference to the drawings.

[0020] A turbo refrigerator is an air conditioning device installed in a factory or large facility and operated as a heat source. In addition, the refrigerant used in the turbo refrigerator is a refrigerant of the HFO (hydrofluoroolefin: hydrofluoroolefin) series or HFC (hydrofluorocarbon: hydrofluorocarbon) series with a small global warming potential (GWP). Specific examples of the refrigerant include HFO-1233zd (E), HFO-1234ze (E) and HFC-134a.

[0021] like Figure 1 As shown, the turbo refrigerator 100 in the present embodiment includes a turbo compressor 1 , a condenser 2 , an expansion valve 3 , an evaporator 4 , a refrigerant supply unit 5 , a condenser pipe 6 , a connecting pipe 7 , and an evaporator pipe 8 .

[0022] (Turbo compressor)

[0023] The turbo compressor 1 is a device that applies kinetic energy due to the centrifugal force of an impeller to sucked refrigerant, compresses the refrigerant to a predetermined high pressure, and discharges the refrigerant.

[0024] The turbo compressor 1 in this embodiment includes a housing 10, a shaft 11, an electric motor 12, an impeller 13, a magnetic bearing 14, a displacement sensor 15, a casing 16, a heat transfer plate 17, a magnetic bearing drive substrate 18, a displacement sensor substrate 20, and a cooling unit 19 (see Figure 2 ).

[0025] (case)

[0026] The casing 10 constitutes an outer shell of the turbo compressor 1. The casing 10 accommodates various devices constituting the turbo compressor 1. The casing 10 has, for example, a cylindrical shape in which both ends are closed in a state of extending in one direction.

[0027] The housing 10 has an outer surface 10a exposed to the atmosphere. The housing 10 is fixed to the ground or a ground surface such as a base. The housing 10 in the present embodiment is formed of a metal material such as iron.

[0028] (Shaft)

[0029] The shaft portion 11 is a cylindrical rotating shaft centered on the central axis O as a virtual axis and extending in the direction in which the central axis O extends. In the following, for the sake of convenience, the extension direction of the central axis O centered on the shaft portion 11 is referred to as the "axial direction Da". The axial direction Da is consistent with the direction in which the housing 10 extends, that is, the above-mentioned one direction. In addition, of the two sides of the axial direction Da, one side ( Figure 1 The right side of the Dar is referred to as "Dar" and the opposite side ( Figure 1 The left side in the middle) is called the "other side Dal".

[0030] The circumferential direction relative to the central axis O (or the shaft portion 11) is referred to as the "circumferential direction Dc". The direction perpendicular to the central axis O is referred to as the "radial direction". The shaft portion 11 is accommodated in the housing 10. The shaft portion 11 in the present embodiment is formed of a metal material such as iron.

[0031] (Electric Motor)

[0032] The electric motor 12 is a device that uses electromagnetic force generated by input electric power to drive the shaft 11 to rotate around the central axis 0. The electric motor 12 is accommodated in the housing 10.

[0033] The electric motor 12 has a motor rotor 12 a and a motor stator 12 b .

[0034] The motor rotor 12a is rotatable together with the shaft portion 11 about the central axis O and is a rotor of the electric motor 12. The motor rotor 12a is integrally attached to the shaft portion 11 in a cylindrical state so as to cover the shaft portion 11 from the outer peripheral side.

[0035] The motor stator 12b rotates the motor rotor 12a by being driven. That is, the motor stator 12b is a stator for the above-mentioned rotor (motor rotor 12a). The motor stator 12b is mounted on the inner surface of the housing 10 in a cylindrical state so as to cover the motor rotor 12a from the outer peripheral side. When the electric motor 12 is driven, the inner peripheral surface of the motor stator 12b faces the outer peripheral surface of the motor rotor 12a in the radial direction through a gap.

[0036] The motor stator 12b is electrically connected to an inverter device (not shown) such as a variable frequency drive (VFD) disposed outside the housing 10, and is driven by the inverter device. By applying a three-phase AC voltage to the coils of the motor stator 12b from the inverter device, an electromagnetic force is generated to rotate the motor rotor 12a around the central axis O.

[0037] (impeller)

[0038] The impeller 13 rotates together with the shaft 11, compresses the gaseous refrigerant supplied from the outside of the turbo compressor 1, and discharges the compressed refrigerant. The impeller 13 is accommodated in the casing 10. The impeller 13 is arranged on the other side Dal than the electric motor 12.

[0039] The impeller 13 in this embodiment includes two wheels 131 and 132 attached to the shaft portion 11 in a state of being separated from each other in the axial direction Da, and an inter-stage pipeline 133 connecting the two wheels 131 and 132 to each other.

[0040] Hereinafter, for convenience of explanation, the wheel of the two wheels 131 and 132 of the impeller 13 arranged on the other side Dal is referred to as the "first wheel 131", and the wheel arranged closer to one side Dar than the first wheel 131 is referred to as the "second wheel 132".

[0041] The first wheel 131 boosts the refrigerant supplied from the outside of the turbo compressor 1 to a predetermined first pressure value.

[0042] The first wheel 131 includes: a first blade group 131a, which is composed of a plurality of blades arranged along the circumferential direction Dc of the shaft portion 11 when fixed to the shaft portion 11; and a first wheel housing 131b, which forms a compression passage inside together with the first blade group 131a in a state of covering the first blade group 131a from the outer peripheral side of the shaft portion 11. The first wheel housing 131b is formed with a first refrigerant inlet for introducing refrigerant from the outside into the compression passage and a first refrigerant outlet for discharging the compressed refrigerant from the compression passage to the outside.

[0043] The second wheel 132 increases the refrigerant compressed by the first wheel 131 to a predetermined second pressure value higher than the first pressure value.

[0044] The second wheel 132 includes: a second blade group 132a, which is composed of a plurality of blades (wings) arranged in the circumferential direction Dc of the shaft portion 11 when fixed to the shaft portion 11; and a second wheel housing 132b, which forms a compression passage inside together with the second blade group 132a while covering the second blade group 132a from the outer peripheral side of the shaft portion 11. The second wheel housing 132b is formed with a second refrigerant inlet for introducing refrigerant from the outside into the compression passage and a second refrigerant outlet for discharging the compressed refrigerant from the compression passage to the outside.

[0045] The first refrigerant discharge port in the first wheel 131 and the second refrigerant inlet in the second wheel 132 are connected through the inter-stage pipe 133 so that the refrigerant can flow.

[0046] Therefore, the refrigerant introduced from the outside into the compression channel of the first wheel 131 through the first refrigerant inlet in the first wheel 131 is compressed in the compression channel by the first blade group 131a rotating around the central axis O as the shaft portion 11 rotates, and then flows into the interstage pipeline 133 through the first refrigerant outlet. The refrigerant flowing into the interstage pipeline 133 flows into the compression channel of the second wheel 132 through the second refrigerant inlet in the second wheel 132, and is compressed by the second blade group 132a in the compression channel. The refrigerant compressed in the compression channel of the second wheel 132 is discharged to the outside through the second refrigerant outlet in the second wheel 132.

[0047] That is, the impeller 13 including the first wheel 131 and the second wheel 132 constitutes a two-stage compression mechanism in the turbo compressor 1 .

[0048] (Magnetic Bearings)

[0049] The magnetic bearing 14 is a radial magnetic bearing that rotatably supports the shaft portion 11 by magnetically floating the shaft portion 11. The magnetic bearing 14 is accommodated in the housing 10.

[0050] The magnetic bearing 14 in the present embodiment is composed of a first magnetic bearing 14 a and a second magnetic bearing 14 b which are arranged in a state separated from each other in the axial direction Da so as to sandwich the electric motor 12 therebetween.

[0051] The first magnetic bearing 14a and the second magnetic bearing 14b support the shaft portion 11 in the radial direction of the central axis O (in the radial direction of the shaft portion 11). The first magnetic bearing 14a and the second magnetic bearing 14b cover the shaft portion 11 from the outer peripheral side.

[0052] The first magnetic bearing 14a is disposed, for example, between the electric motor 12 and the second wheel 132 of the impeller 13. The inner surface of the first magnetic bearing 14a faces the outer peripheral surface of the shaft portion 11 with a gap therebetween in the radial direction of the central axis O.

[0053] The first magnetic bearing 14a is electrically connected to a magnetic bearing drive substrate 18 disposed outside the housing 10. By applying a three-phase AC voltage from the magnetic bearing drive substrate 18 to a coil (driving the first magnetic bearing 14a) of the first magnetic bearing 14a, an electromagnetic force is generated to cause the shaft 11 to be magnetically levitated in a non-contact state with the first magnetic bearing 14a.

[0054] The second magnetic bearing 14b is disposed on one side Dar of the electric motor 12. The inner surface of the second magnetic bearing 14b faces the outer peripheral surface of the shaft portion 11 in the radial direction of the central axis O with a gap therebetween.

[0055] Similar to the first magnetic bearing 14a, the second magnetic bearing 14b is electrically connected to the magnetic bearing drive substrate 18. By applying a three-phase AC voltage from the magnetic bearing drive substrate 18 to a coil (driving the second magnetic bearing 14b) of the second magnetic bearing 14b, an electromagnetic force is generated to cause the shaft 11 to be magnetically levitated in a non-contact state with the second magnetic bearing 14b.

[0056] In addition, although detailed illustrations are omitted, for example, on a side Dar closer to the second magnetic bearing 14b, a flange portion is formed that extends radially from the shaft portion 11 and is integrally formed with the shaft portion 11 into a disc shape, and the flange portion is supported in a state of being clamped from the axial direction Da, and a thrust magnetic bearing is configured to position the shaft portion 11 in the axial direction Da (thrust direction of the shaft portion 11).

[0057] (Displacement Sensor)

[0058] The displacement sensor 15 detects the size of a gap formed between the shaft portion 11 and the magnetic bearing 14 in the radial direction when the magnetic bearing 14 is driven. The displacement sensor 15 is accommodated in the housing 10.

[0059] The displacement sensor 15 in this embodiment is composed of a first displacement sensor 15a and a second displacement sensor 15b which are arranged to be separated from each other in the axial direction Da and sandwich the electric motor 12. The first displacement sensor 15a and the second displacement sensor 15b are electrically connected to a displacement sensor substrate 20 arranged outside the housing 10.

[0060] The first displacement sensor 15a detects the size of the gap between the shaft 11 and the first magnetic bearing 14a. The second displacement sensor 15b detects the size of the gap between the shaft 11 and the second magnetic bearing 14b. The first displacement sensor 15a and the second displacement sensor 15b transmit signals indicating the size of the detected gap to the displacement sensor substrate 20.

[0061] (Box)

[0062] The housing 16 is a housing (frame) that accommodates the magnetic bearing drive substrate 18 that drives the magnetic bearing 14 and the displacement sensor substrate 20 that processes the detection result received from the displacement sensor 15. Figure 1 and Figure 2 As shown, the box body 16 in this embodiment is installed on the outer surface 10 a of the housing 10 .

[0063] Specifically, if Figure 2 As shown, the box body 16 is attached to the outer surface 10 a of the housing 10 , which extends parallel to a virtual plane that can be defined by the up-down direction Dv and the axial direction Da.

[0064] The up-down direction Dv in this specification is consistent with the vertical direction. Figure 2 Middle and Figure 3 The lower side in the figure is called the "lower side DVD", and the opposite side ( Figure 2 Middle and Figure 3 The upper side in the figure is called the “upper side Dvu”.

[0065] The box 16 has a rectangular parallelepiped shape with a rectangular opening 16a formed on one surface. The box 16 is fixed to the outer surface 10a of the housing 10 by fastening members B such as bolts, with the opening 16a facing the outer surface 10a of the housing 10.

[0066] The box body 16 can be removed from the housing 10 by removing the fastening member B. That is, the box body 16 is detachably mounted to the housing 10. The box body 16 in the present embodiment is formed of a metal material including aluminum, for example.

[0067] (Heat transfer plate)

[0068] The heat transfer plate 17 is a metal plate for cooling the magnetic bearing drive substrate 18 accommodated in the housing 16. The heat transfer plate 17 is formed in a rectangular flat plate shape. The heat transfer plate 17 is embedded in the opening 16a of the housing 16 without a gap. The heat transfer plate 17 is embedded in the opening 16a of the housing 16 to make the inside of the housing 16 a closed space that is airtightly isolated from the outside. Hereinafter, for convenience of explanation, the space in the housing 16 set as a closed space is referred to as "accommodation space R".

[0069] The heat transfer plate 17 has one surface 17 a that contacts the outer surface 10 a of the housing 10 when attached to the outer surface 10 a of the housing 10 , and another surface 17 b that faces the opposite side to the one surface 17 a .

[0070] One surface 17a of the heat transfer plate 17 is fixed to the outer surface 10a of the housing 10 in direct surface contact. The other surface 17b of the heat transfer plate 17 faces the accommodation space R. The heat transfer plate 17 in this embodiment is formed of a metal material including aluminum, for example.

[0071] (Magnetic bearing drive substrate)

[0072] The magnetic bearing drive substrate 18 is a magnetic bearing controller substrate (MBC) for inputting driving power to the magnetic bearings 14 (the first magnetic bearing 14a and the second magnetic bearing 14b). The magnetic bearing drive substrate 18 is accommodated in the housing 16. That is, the magnetic bearing drive substrate 18 is arranged in the accommodation space R. The magnetic bearing drive substrate 18 is in the shape of a flat plate. The magnetic bearing drive substrate 18 is mounted on the heat transfer plate 17.

[0073] The magnetic bearing drive substrate 18 includes a contact surface 18 a that is in surface contact with the other surface 17 b of the heat transfer plate 17 , and a mounting surface 18 b that faces the opposite side of the contact surface 18 a and on which various circuit elements are mounted.

[0074] In addition, the wiring that electrically connects the magnetic bearing drive substrate 18 to the magnetic bearing 14 is extended from the magnetic bearing drive substrate 18 to the outside of the case 16 through the side wall of the case 16 in order to ensure the sealing of the storage space R in the case 16. The front end of the extension reaches the first magnetic bearing 14a and the second magnetic bearing 14b disposed in the housing 10, respectively.

[0075] (Displacement sensor substrate)

[0076] The displacement sensor substrate 20 is a circuit substrate for receiving a signal indicating a detection result (the size of the gap) transmitted from the displacement sensor 15 (the first displacement sensor 15 a and the second displacement sensor 15 b ) and for processing the detection result.

[0077] The displacement sensor substrate 20 is accommodated in the housing 16 together with the magnetic bearing drive substrate 18. That is, the displacement sensor substrate 20 is arranged in the accommodation space R. The displacement sensor 15 is mounted on, for example, the inner surface 16b of the housing 16 and supported by the inner surface 16b. The displacement sensor substrate 20 in this embodiment does not contact the heat transfer plate 17.

[0078] In addition, the wiring that electrically connects the displacement sensor substrate 20 and the displacement sensor 15 extends from the displacement sensor substrate 20 toward the outside of the case 16 and penetrates the side wall of the case 16 in a manner that ensures the airtightness of the storage space R in the case 16. The leading ends of the extensions reach the first displacement sensor 15a and the second displacement sensor 15b disposed in the housing 10, respectively.

[0079] Here, the storage space R in the housing 16 is replaced with an inert gas. Specifically, for example, by driving a gas replacement device (not shown) provided in the housing 16, the air in the storage space R is replaced with nitrogen. Therefore, the magnetic bearing drive substrate 18 and the displacement sensor substrate 20 accommodated in the housing 16 are placed in an inert gas environment.

[0080] The inert gas in this embodiment can be, for example, nitrogen (N2), etc. In addition, “replaced with inert gas” here means that the atmosphere in the storage space R is substantially replaced with inert gas, and the atmosphere in the storage space R is allowed to include a small amount of air.

[0081] (Cooling section)

[0082] When a refrigerant is supplied from the outside, the cooling unit 19 transfers the cold heat of the supplied refrigerant to the heat transfer plate 17 .

[0083] like Figure 2 As shown, the cooling unit 19 in this embodiment includes a flow path portion 190 and a groove portion 193 formed on the heat transfer plate 17 .

[0084] The flow path portion 190 is formed in the outer wall of the housing 10 .

[0085] The flow path 190 includes a first flow path 191 that allows refrigerant introduced from outside the housing 10 to flow and guides the refrigerant to the groove 193 , and a second flow path 192 that allows refrigerant flowing out of the groove 193 to flow and guides the refrigerant to the outside of the housing 10 .

[0086] The first flow path 191 and the second flow path 192 extend in the outer wall of the housing 10 and are not connected to the space inside the housing 10. One end of the first flow path 191 opens on an outer surface 10a different from the outer surface 10a of the housing 10 that abuts against one surface 17a of the heat transfer plate 17. The other end of the first flow path 191 is connected to the groove 193.

[0087] One end of the second flow path portion 192 opens on an outer surface 10a different from the outer surface 10a of the housing 10 that contacts the one surface 17a of the heat transfer plate 17. The other end of the second flow path portion 192 is connected to the groove portion 193.

[0088] The groove 193 is a groove formed on the heat transfer plate 17. The groove 193 is recessed from one surface 17a of the heat transfer plate 17 toward the other surface 17b. The groove 193 is recessed from one surface 17a toward the other surface 17b to form a flow path for the refrigerant to flow along the outer surface 10a of the shell 10 that contacts the one surface 17a of the heat transfer plate 17. Figure 3 As shown, the groove 193 in this embodiment extends in a meandering manner along one surface 17 a of the heat transfer plate 17 .

[0089] Specifically, the groove portion 193 is composed of a plurality of extension grooves 193a extending in the axial direction Da and a plurality of connection grooves 193b extending in the vertical direction Dv when the heat transfer plate 17 is mounted on the outer surface 10a of the housing 10. The extension grooves 193a and the connection grooves 193b are connected to each other in a manner that they extend alternately and repeatedly, thereby forming the groove portion 193 that meanders along one surface 17a of the heat transfer plate 17.

[0090] Therefore, the refrigerant flowing into the groove portion 193 flows in a meandering manner along the one side 17a of the heat transfer plate 17. In the present embodiment, the four extension grooves 193a are arranged at equal intervals in the vertical direction Dv in a state along the one side 17a of the heat transfer plate 17, and the three connecting grooves 193b are connected to each other in the vertical direction Dv at the ends of the four extension grooves 193a adjacent to each other in the vertical direction Dv in the axial direction Da. The width dimension (dimension in the vertical direction Dv) of these extension grooves 193a and the width dimension (dimension in the axial direction Da) of the connecting grooves 193b are set to be the same.

[0091] Here, the other end of the first flow path portion 191 is connected to the other side Dal (which is the side of the extended groove 193a arranged at the lowermost side Dvd that is not connected to the connecting groove 193b). Figure 3 The end of the left side in the figure is connected.

[0092] The other end of the second flow path portion 192 is connected to the side Dar ( Figure 3The end of the left side in the figure is connected.

[0093] (Condenser)

[0094] The condenser 2 is a heat exchanger that receives the refrigerant in a gas state discharged from the impeller 13 of the turbo compressor 1 and condenses the refrigerant. Figure 1 As shown, the condenser 2 is arranged outside the turbo compressor 1 .

[0095] Here, the condenser 2 is connected to the turbo compressor 1 through a condenser pipe 6. The condenser pipe 6 in this embodiment is a connecting pipe through which the refrigerant flows. Specifically, one end of the condenser pipe 6 is connected to the refrigerant outlet of the second wheel 132 in the impeller 13, and the other end of the condenser pipe 6 is connected to the refrigerant inlet of the condenser 2. Therefore, the refrigerant compressed by the impeller 13 of the turbo compressor 1 is guided to the inside of the condenser 2 through the condenser pipe 6.

[0096] The condenser 2 is provided with a heat transfer tube 21 through which cooling water for cooling the refrigerant flows. The cooling water flowing in the heat transfer tube 21 is heated by exchanging heat with the refrigerant through the heat transfer tube 21 in the condenser 2. The heated cooling water flows through the heat transfer tube 21 toward the outside of the condenser 2, and is introduced into a cooling tower or the like (not shown) provided outside the turbo refrigerator 100 to be cooled (heat is discharged). The cooling water cooled outside the condenser 2 flows into the heat transfer tube 21 again, flows in the heat transfer tube 21 toward the condenser 2, and exchanges heat with the refrigerant again in the condenser 2.

[0097] The refrigerant cooled by heat exchange in the condenser 2 is condensed and becomes a liquid state. The liquid refrigerant is stored in the condenser 2. The temperature of the liquid refrigerant stored in the condenser 2 is, for example, in the range of 35°C to 45°C.

[0098] The refrigerant in a liquid state stored in the condenser 2 flows toward the evaporator 4 along the connecting pipe 7 connecting the condenser 2 and the evaporator 4 to each other. The connecting pipe 7 in this embodiment is a connecting pipe through which the refrigerant flows. Specifically, one end of the connecting pipe 7 is connected to the refrigerant outlet of the condenser 2, and the other end of the connecting pipe 7 is connected to the refrigerant inlet of the evaporator 4.

[0099] (Expansion valve)

[0100] The expansion valve 3 adiabatically expands the refrigerant in a liquid state from the condenser 2 flowing in the connecting pipe 7, thereby reducing the pressure and temperature of the refrigerant flowing in the connecting pipe 7. The expansion valve 3 is provided in the connecting pipe 7. Therefore, the refrigerant adiabatically expanded by the expansion valve 3 is guided to the evaporator 4 through the connecting pipe 7. In addition, the refrigerant flowing from the expansion valve 3 to the evaporator 4 through the connecting pipe 7 is in a liquid state.

[0101] (Evaporator)

[0102] The evaporator 4 is a heat exchanger that receives and stores the liquid refrigerant adiabatically expanded by the expansion valve 3 , and evaporates the stored refrigerant. The evaporator 4 is disposed outside the turbo compressor 1 .

[0103] Here, the evaporator 4 is connected to the turbo compressor 1 through an evaporator pipe 8. The evaporator pipe 8 in this embodiment is a connecting pipe through which the refrigerant flows. Specifically, one end of the evaporator pipe 8 is connected to the refrigerant outlet of the evaporator 4, and the other end of the evaporator pipe 8 is connected to the refrigerant inlet of the first wheel 131 in the impeller 13. Therefore, the refrigerant evaporated in the evaporator 4 and turned into a gas state is guided to the turbo compressor 1 through the evaporator pipe 8.

[0104] A heat transfer tube 41 is inserted into the evaporator 4, through which a heat medium for heating the refrigerant flows. The heat medium flowing in the heat transfer tube 41 may be cold water introduced from a device outside the turbo refrigerator 100 or the like. The heat medium flowing in the heat transfer tube 41 is cooled by exchanging heat with the refrigerant through the heat transfer tube 41 in the evaporator 4. The cooled heat medium flows in the heat transfer tube 41 toward the outside of the evaporator 4, and is introduced into a device (not shown) provided outside the turbo refrigerator 100 to be heated (cold and heat recovery). The heat medium heated in the device outside the evaporator 4 flows into the heat transfer tube 41 again, flows in the heat transfer tube 41 toward the evaporator 4, and exchanges heat with the refrigerant again in the evaporator 4.

[0105] The refrigerant heated by heat exchange in the evaporator 4 evaporates and becomes a gaseous state. The gaseous refrigerant is guided to the turbo compressor 1 through the evaporator pipe 8. The temperature of the liquid refrigerant stored in the evaporator 4 is, for example, in the range of 0°C to 10°C.

[0106] (Refrigerant supply unit)

[0107] The refrigerant supply unit 5 takes out a part of the liquid refrigerant stored in the condenser 2 as a heat medium for cooling, and supplies the part to the turbo compressor 1 .

[0108] The refrigerant supply unit 5 in the present embodiment includes a first introduction line 51 , a first regulating valve 52 , a first discharge line 53 , a second introduction line 54 , a second regulating valve 55 , and a second discharge line 56 .

[0109] (First inlet pipeline)

[0110] The first introduction pipe 51 is a pipe that connects the condenser 2 and the shell 10 of the turbo compressor 1. Specifically, one end of the first introduction pipe 51 is connected to the refrigerant outlet of the condenser 2, and the other end of the first introduction pipe 51 is connected to the refrigerant inlet formed in the shell 10. Therefore, the liquid refrigerant stored in the condenser 2 flows toward the inside of the shell 10 through the first introduction pipe 51.

[0111] (First regulating valve)

[0112] The first regulating valve 52 reduces the pressure and temperature of the refrigerant flowing in the first inlet pipe 51 by reducing the pressure of the liquid refrigerant from the condenser 2 flowing in the first inlet pipe 51. The first regulating valve 52 in this embodiment is a pressure regulating valve. The first regulating valve 52 is provided in the first inlet pipe 51.

[0113] The first regulating valve 52 decompresses the refrigerant flowing in the first inlet pipe 51 to convert the refrigerant from a liquid state to a gas-liquid two-phase state. The refrigerant in the gas-liquid two-phase state after passing through the first regulating valve 52 is guided into the interior of the casing 10 of the turbo compressor 1 through the first inlet pipe 51.

[0114] (First discharge line)

[0115] The first discharge pipe 53 is a pipe connecting the casing 10 of the turbo compressor 1 and the evaporator 4. Specifically, one end of the first discharge pipe 53 is connected to a refrigerant discharge port formed in the casing 10, and the other end of the first discharge pipe 53 is connected to a refrigerant inlet of the evaporator 4.

[0116] The refrigerant introduced into the housing 10 through the first introduction line 51 cools various devices accommodated in the housing 10 and is then guided to the evaporator 4 through the first discharge line 53. The refrigerant guided into the housing 10 mainly cools the electric motor 12, the magnetic bearing 14 and the housing 10.

[0117] (Second inlet pipe)

[0118] The second introduction pipe 54 is a pipe that connects the first introduction pipe 51 and the cooling unit 19 of the turbo compressor 1 to each other. Figure 1 and Figure 2As shown, one end of the second introduction line 54 is connected to a portion closer to the condenser 2 than the first adjustment valve 52 in the first introduction line 51. The other end of the second introduction line 54 is connected to the above-mentioned one end of the first flow path portion 191 in the cooling unit 19. The liquid refrigerant stored in the condenser 2 flows toward the first flow path portion 191 through the second introduction line 54 connected to the branch from the first introduction line 51.

[0119] (Second adjustment valve)

[0120] The second regulating valve 55 reduces the pressure and temperature of the refrigerant flowing in the second introduction pipe 54 by reducing the pressure of the liquid refrigerant flowing in the second introduction pipe 54. The second regulating valve 55 in this embodiment is a pressure regulating valve.

[0121] The second regulating valve 55 decompresses the refrigerant flowing in the second inlet pipe 54, thereby converting the refrigerant from a liquid state to a gas-liquid two-phase state. The refrigerant that has become a gas-liquid two-phase state by passing through the second regulating valve 55 is guided to the inside of the first flow path 191 of the cooling unit 19 through the second inlet pipe 54.

[0122] (Second discharge line)

[0123] The second discharge pipe 56 is a pipe connecting the second flow path 192 of the cooling unit 19 and the evaporator 4. Specifically, one end of the second discharge pipe 56 is connected to the one end of the second flow path 192, and the other end of the second discharge pipe 56 is connected to the refrigerant inlet of the evaporator 4.

[0124] The refrigerant introduced into the first flow path 191 through the second introduction pipe 54 flows through the groove 193 in the cooling unit 19, transfers cold heat to the heat transfer plate 17, and then flows into the second flow path 192. The refrigerant flowing into the second flow path 192 is guided to the evaporator 4 through the second discharge pipe 56.

[0125] (Effect)

[0126] When the magnetic bearing 14 is driven and the shaft 11 is magnetically levitated, a large current flows in the magnetic bearing drive substrate 18. When the magnetic bearing 14 is driven, the magnetic bearing drive substrate 18 becomes a high heat generating component.

[0127] According to the above structure, the magnetic bearing drive substrate 18 is in surface contact with the heat transfer plate 17, so the heat generated from the magnetic bearing drive substrate 18 is transferred to the heat transfer plate 17. The heat transferred to the heat transfer plate 17 is transferred to the housing 10 to which the heat transfer plate 17 is mounted. Therefore, for example, compared with the case where there is no heat transfer plate 17 between the magnetic bearing drive substrate 18 and the housing 10, the heat of the magnetic bearing drive substrate 18 can be transferred more efficiently. Therefore, for example, it is not necessary to form the entire housing 10 with a metal having a relatively high thermal conductivity such as aluminum, and the heat generated by the magnetic bearing drive substrate 18 can be smoothly released into the housing 10. As a result, the cost increase generated when manufacturing the turbo compressor 1 can be suppressed.

[0128] Furthermore, the groove 193 in the cooling portion 19 is formed on the heat transfer plate 17, and the refrigerant supplied from the outside flows in the groove 193, whereby the heat of the refrigerant is transferred to the heat transfer plate 17. Therefore, for example, compared with a case where the groove 193 is not formed on the heat transfer plate 17, the magnetic bearing drive substrate 18 can be cooled more stably without being affected by the temperature of the housing 10 during the operation of the turbo compressor 1 or the material of the housing 10.

[0129] Furthermore, according to the above configuration, the cooling portion 19 for cooling the heat transfer plate 17 can be formed by a simple method such as forming the flow path portion 190 in the housing 10 and forming the groove portion 193 in the heat transfer plate 17. Therefore, for example, compared with a case where a device such as a blower capable of air cooling the heat transfer plate 17 is used as the cooling portion, an increase in the number of parts of the turbo compressor 1 and an increase in the maintenance frequency can be suppressed.

[0130] Furthermore, according to the above configuration, since the groove 193 in the cooling unit 19 extends in a meandering manner along the one surface 17a of the heat transfer plate 17, the heat of the refrigerant can be more effectively transferred to the heat transfer plate 17 compared to a case where the groove 193 does not extend in a meandering manner.

[0131] Furthermore, according to the above structure, the magnetic bearing drive substrate 18 is accommodated in the housing 16, and the air in the space inside the housing 16 is replaced by an inert gas in a state where the air is hermetically isolated from the outside. Therefore, when the magnetic bearing drive substrate 18 is cooled by the heat of the refrigerant, it is possible to suppress the generation of moisture in the magnetic bearing drive substrate 18 due to condensation. Therefore, it is possible to suppress abnormalities such as damage in the magnetic bearing drive substrate 18 caused by the cooling of the magnetic bearing drive substrate 18 caused by the heat of the refrigerant. As a result, it is possible to achieve a longer life of the magnetic bearing drive substrate 18. Furthermore, the magnetic bearing drive substrate 18 is accommodated in the housing 16, so that the magnetic bearing drive substrate 18 is not exposed to the atmosphere, so that, for example, it is possible to suppress the influence of heat such as radiant heat or convection heat generated from the magnetic bearing drive substrate 18 on other equipment.

[0132] Furthermore, according to the above-mentioned structure, the displacement sensor substrate 20 for processing the signal detected by the displacement sensor 15 is accommodated in the housing 16 together with the magnetic bearing drive substrate 18. Therefore, for example, by removing the housing 16 from the shell 10, it is possible to simultaneously maintain these displacement sensor substrates 20 and the magnetic bearing drive substrate 18. In addition, the heat resistance of the displacement sensor substrate 20 is sometimes lower than that of the magnetic bearing drive substrate 18. As a result of cooling the magnetic bearing drive substrate 18 by the heat transfer plate 17 and the cooling portion 19, the heat effects such as radiant heat or convection heat received by the displacement sensor substrate 20 from the magnetic bearing drive substrate 18 are suppressed. As a result, the space (accommodation space R) for setting the displacement sensor substrate 20 can be shared with the magnetic bearing drive substrate 18, thereby suppressing the enlargement of the turbo compressor 1.

[0133] Furthermore, according to the above structure, since the heat transfer plate 17 is formed of a metal material including aluminum, the heat transfer plate 17 can be easily processed and can be manufactured at a low cost. In addition, the heat transfer plate 17 is embedded in the opening 16a of the housing 16, so that the heat generated by the magnetic bearing drive substrate 18 can be transferred to the housing 16.

[0134] Furthermore, according to the above configuration, the refrigerant condensed by the condenser 2 of the turbo refrigerator 100 is guided to the cooling unit 19 through the refrigerant supply unit 5. Therefore, for example, it is not necessary to separately provide a device for supplying a cooling refrigerant to the cooling unit 19 in the turbo refrigerator 100. As a result, it is possible to suppress the turbo compressor 1 from being enlarged.

[0135] Furthermore, according to the above-mentioned structure, the refrigerant from the condenser 2 flowing in the second introduction pipe 54 of the refrigerant supply unit 5 is decompressed by the second regulating valve 55 to become a gas-liquid two-phase state, and then supplied to the cooling unit 19. Therefore, compared with the case where only the liquid state refrigerant is supplied to the cooling unit 19, for example, the temperature of the refrigerant supplied to the cooling unit 19 can be lowered, and the amount of the refrigerant taken out from the condenser 2 can be suppressed. As a result, while transferring cold and heat to the heat transfer plate 17, it is possible to suppress a decrease in the coefficient of performance (COP: Coe fficient Of Performance) indicating the ratio of power to refrigeration capacity when the turbo refrigerator 100 is operated.

[0136] (Other embodiments)

[0137] The embodiments of the present invention have been described in detail above with reference to the drawings, but the specific structure is not limited to the structure of the embodiment, and addition, omission, replacement and other changes of the structure can be made within the scope not departing from the spirit of the present invention.

[0138] In addition, in the above-mentioned embodiment, the structure in which the first regulating valve 52 is provided in the first inlet pipe 51 and the second regulating valve 55 is provided in the second inlet pipe 54 is described, but it is not limited to this structure. For example, the first regulating valve 52 and the second regulating valve 55 can share one regulating valve. In this case, the regulating valve can be provided on the condenser 2 side more than the connection part of the first inlet pipe 51 and the second inlet pipe 54. Therefore, instead of the structure in which the refrigerant supply part 5 has the first regulating valve 52 and the second regulating valve 55, the refrigerant supply part 5 can have a structure in which the regulating valve is provided on the condenser 2 side more than the connection part of the first inlet pipe 51 and the second inlet pipe 54.

[0139] Furthermore, the first regulating valve 52 and the second regulating valve 55 can be adjusted to have different openings. That is, the proportions of the gas phase component and the liquid phase component of the refrigerant introduced into the shell 10 through the first introduction pipe 51 and the proportions of the gas phase component and the liquid phase component of the refrigerant introduced into the cooling unit 19 through the second introduction pipe 54 can be different.

[0140] Furthermore, in the above-mentioned embodiment, the groove 193 in the cooling unit 19 is not limited to a structure extending in a meandering manner along the one surface 17a. The groove 193 may be, for example, a single groove (large hole) formed to extend along the one surface 17a.

[0141] In addition, the groove portion 193 of the cooling portion 19 may be formed in the housing 10 in a manner recessed from the outer surface 10 a of the housing 10 , instead of being formed in the heat transfer plate 17 .

[0142] Furthermore, in the above-mentioned embodiment, the structure in which the four extension grooves 193a are arranged at equal intervals in the vertical direction Dv along the one surface 17a of the heat transfer plate 17, and the three connecting grooves 193b are connected to each other in the vertical direction Dv at the ends of the four adjacent extension grooves 193a in the axial direction Da, is described, but the present invention is not limited to this structure. For example, the number of the extension grooves 193a is five or more, and the number of the connecting grooves 193b is four or more. Furthermore, for example, the number of the extension grooves 193a may be three or less, and the number of the connecting grooves 193b may be two or less.

[0143] Furthermore, in the above-mentioned embodiment, the inert gas used for replacing the air in the storage space R in the housing 16 is not limited to nitrogen gas, but may be argon gas (Ar) or helium gas (He), for example.

[0144] Furthermore, in the above-mentioned embodiment, the housing 16 is not limited to the structure formed of a metal material including aluminum. The housing 16 may be formed of a metal material including iron or the like, or a synthetic resin material, for example.

[0145] Furthermore, in the above-mentioned embodiment, the structure in which the one side 17a of the heat transfer plate 17 is in direct surface contact with the outer surface 10a of the housing 10 is described, but the present invention is not limited to this structure. In order to make the one side 17a of the heat transfer plate 17 and the outer surface 10a of the housing 10 more closely fit, the one side 17a of the heat transfer plate 17 can be fixed to the outer surface 10a in a state of being closely fitted to the outer surface 10a, for example, by means of heat dissipation grease.

[0146] Furthermore, in the above-mentioned embodiment, the case where the impeller 13 having the first wheel 131 and the second wheel 132 constitutes a two-stage compression mechanism in the turbo compressor 1 is described, but the present invention is not limited to this structure. By having the impeller 13 having only a single wheel, a one-stage (single-stage) compression mechanism can also be constituted in the turbo compressor 1.

[0147] Furthermore, the terms “parallel”, “perpendicular” and “identical” described in the above embodiments refer to substantially parallel, perpendicular and identical states, and allow for slight manufacturing errors and design tolerances.

[0148] [Note]

[0149] The turbo compressor and the turbo refrigerator including the turbo compressor described in the embodiment can be understood, for example, as follows.

[0150] (1) The turbo compressor 1 involved in the first embodiment includes: an impeller 13; a shaft 11 that rotates the impeller 13; an electric motor 12 that rotationally drives the shaft 11; a housing 10 that accommodates the electric motor 12; a magnetic bearing 14 that supports the shaft 11; a heat transfer plate 17 with one surface 17a mounted on an outer surface 10a of the housing 10; a magnetic bearing drive substrate 18, with the other surface 17b of the heat transfer plate 17 on the side opposite to the one surface 17a being in surface contact; and a cooling unit 19 that transfers the cold heat of the supplied refrigerant to the heat transfer plate 17 by supplying the refrigerant from the outside.

[0151] Thus, the heat generated from the magnetic bearing drive substrate 18 is transferred to the heat transfer plate 17, and the heat transferred from the heat transfer plate 17 is transferred to the housing 10. Therefore, instead of forming the entire housing 10 with a metal having a high thermal conductivity, the heat generated by the magnetic bearing drive substrate 18 can be released to the housing 10. Furthermore, by transferring the cold heat of the refrigerant to the heat transfer plate 17, the magnetic bearing drive substrate 18 can be cooled more stably without being affected by the temperature of the housing 10 or the material of the housing 10 during the operation of the turbo compressor 1.

[0152] (2) The turbo compressor 1 involved in the second embodiment is the turbo compressor 1 of (1), wherein the cooling portion 19 may include: a flow path portion 190 formed in the outer wall of the shell 10 and in which the refrigerant flows; and a groove portion 193 connected to the flow path portion 190 and recessed from the one surface 17a of the heat transfer plate 17 toward the other surface 17b, thereby forming a flow path for the refrigerant together with the outer surface 10a of the shell 10.

[0153] Thus, the above-mentioned action can be achieved with higher accuracy. Furthermore, the cooling portion 19 for cooling the heat transfer plate 17 can be formed by a simple method such as forming the flow path portion 190 in the housing 10 and forming the groove portion 193 in the heat transfer plate 17. Furthermore, for example, compared with a case where a device such as a blower capable of air cooling the heat transfer plate 17 is used as the cooling portion, an increase in the number of parts of the turbo compressor 1 and a maintenance frequency can be suppressed.

[0154] (3) The turbo compressor 1 according to the third aspect is the turbo compressor 1 according to (2), wherein the groove portion 193 may extend in a meandering manner along the one surface 17 a of the heat transfer plate 17 .

[0155] Thus, compared with a case where the groove portion 193 does not extend in a meandering manner, the coldness and heat of the refrigerant can be more effectively transferred to the heat transfer plate 17 .

[0156] (4) The turbo compressor 1 involved in the fourth embodiment is any one of the turbo compressors 1 from (1) to (3), which further comprises: a casing 16 that accommodates the magnetic bearing drive substrate 18 in a state where the opening 16a is opposite to the outer surface 10a of the shell 10, and the heat transfer plate 17 is embedded in the opening 16a of the casing 16 to make the inside of the casing 16 an enclosed space that is airtightly isolated from the outside, and the air in the enclosed space can be replaced by an inert gas.

[0157] Thus, when the magnetic bearing drive substrate 18 is cooled by the heat of the refrigerant, it is possible to suppress the generation of moisture in the magnetic bearing drive substrate 18 due to condensation. In addition, the magnetic bearing drive substrate 18 is accommodated in the housing 16, so that the magnetic bearing drive substrate 18 is not exposed to the atmosphere, and thus it is possible to suppress the heat generated from the magnetic bearing drive substrate 18 from affecting other equipment.

[0158] (5) The turbo compressor 1 involved in the fifth embodiment is the turbo compressor 1 of (4), wherein the turbo compressor 1 may further include: a displacement sensor 15 capable of detecting the size of the gap between the shaft portion 11 and the magnetic bearing 14; and a displacement sensor substrate 20, which is accommodated in the housing 16 and processes the signal detected by the displacement sensor 15.

[0159] Thus, the displacement sensor substrate 20 and the magnetic bearing drive substrate 18 can be maintained at the same time by removing the case 16 from the housing 10. Furthermore, since the magnetic bearing drive substrate 18 is cooled by the heat transfer plate 17 and the cooling unit 19, the influence of heat received by the displacement sensor substrate 20 from the magnetic bearing drive substrate 18 is suppressed, so that the space for arranging the displacement sensor substrate 20 can be shared with the magnetic bearing drive substrate 18.

[0160] (6) The turbo compressor 1 according to a sixth aspect is any one of the turbo compressors 1 described in (1) to (5), wherein the heat transfer plate 17 may be formed of a metal material including aluminum.

[0161] Thus, the heat transfer plate 17 can be easily processed and manufactured at a low cost.

[0162] (7) The turbo refrigerator 100 involved in the seventh embodiment comprises: any one of the turbo compressors 1 (1) to (6); a condenser 2 for condensing the refrigerant discharged from the turbo compressor 1; an expansion valve 3 for adiabatically expanding the refrigerant condensed in the condenser 2; an evaporator 4 for evaporating the refrigerant adiabatically expanded in the expansion valve 3; and a refrigerant supply unit 5 for guiding the refrigerant condensed in the condenser 2 to the cooling unit 19.

[0163] Thus, the refrigerant condensed in the condenser 2 is guided to the cooling unit 19 through the refrigerant supply unit 5. Therefore, it is not necessary to separately provide a device for supplying the cooling refrigerant to the cooling unit 19 in the turbo refrigerator 100.

[0164] (8) The turbo refrigerator 100 involved in the eighth embodiment is the turbo refrigerator 100 of (7), wherein the refrigerant supply unit 5 may include: an inlet pipe for guiding the refrigerant to the cooling unit 19; and a regulating valve, which is arranged on the inlet pipe and decompresses the refrigerant flowing in the inlet pipe, thereby making the refrigerant toward the cooling unit 19 into a gas-liquid two-phase state.

[0165] Thus, compared with the case where the refrigerant in a liquid state is supplied to cooling unit 19 , the temperature of the refrigerant supplied to cooling unit 19 can be lowered, and the amount of the refrigerant taken out from condenser 2 can be suppressed.

[0166] Industrial Applicability

[0167] According to the present invention, it is possible to provide a turbo compressor and a turbo refrigerator that can stably cool a magnetic bearing drive substrate while suppressing an increase in cost.

[0168] Explanation of symbols

[0169] 1- turbo compressor, 2- condenser, 3- expansion valve, 4- evaporator, 5- refrigerant supply part, 6- condenser pipeline, 7- connecting pipeline, 8- evaporator pipeline, 10- shell, 10a- outer surface, 11- shaft, 12- electric motor, 12a- motor rotor, 12b- motor stator, 13- impeller, 14- magnetic bearing, 14a- first magnetic bearing, 14b- second magnetic bearing, 15- displacement sensor, 15a- first displacement sensor, 15b- second displacement sensor, 16- housing, 16a- opening, 16b- inner surface, 17- heat transfer plate, 17a- one side, 17b- the other side, 18- magnetic bearing drive substrate, 18a- contact surface, 18b- mounting surface, 19- cooling part, 20- displacement sensor substrate, 21, 41- heat transfer pipe, 51-first inlet pipeline, 52-first regulating valve, 53-first discharge pipeline, 54-second inlet pipeline, 55-second regulating valve, 56-second discharge pipeline, 100-turbine refrigerator, 131-first wheel, 131a-first blade group, 131b-first wheel housing, 132-second wheel, 132a-second blade group, 132b-second wheel housing, 133-interstage pipeline, 190-flow path portion, 191-first flow path portion, 192-second flow path portion, 193-groove portion, 193a-extension groove, 193b-connecting groove, B-fastening component, Da-axial direction, Da1-the other side, Dar-one side, Dc-circumferential direction, Dv-upper and lower directions, Dvd-lower side, Dvu-upper side, 0-center axis, R-accommodation space.

Claims

1. A turbo compressor comprising: impeller; a shaft portion, causing the impeller to rotate; an electric motor, driving the shaft to rotate; a housing for accommodating the electric motor; A magnetic bearing, supporting the shaft; A heat transfer plate, one side of which is mounted on the outer surface of the shell; A magnetic bearing driving substrate in surface contact with another surface of the heat transfer plate opposite to the one surface; and The cooling unit transfers heat of the supplied refrigerant to the heat transfer plate when the refrigerant is supplied from the outside.

2. The turbo compressor according to claim 1, wherein: The cooling unit has: a flow path portion formed in an outer wall of the shell and through which the refrigerant flows; and The groove portion is connected to the flow path portion and is recessed from the one surface of the heat transfer plate toward the other surface, thereby forming a flow path of the refrigerant together with the outer surface of the shell.

3. The turbo compressor according to claim 2, wherein: The groove portion extends in a meandering manner along the one surface of the heat transfer plate.

4. The turbo compressor according to any one of claims 1 to 3, further comprising: a housing for accommodating the magnetic bearing drive substrate in a state where the opening portion faces the outer surface of the housing, The heat transfer plate is inserted into the opening of the box so that the box becomes a closed space that is airtightly isolated from the outside. The air in the closed space is replaced with an inert gas.

5. The turbo compressor according to claim 4, further comprising: a displacement sensor capable of detecting the size of a gap between the shaft and the magnetic bearing; and The displacement sensor substrate is accommodated in the housing and processes the signal detected by the displacement sensor.

6. The turbo compressor according to any one of claims 1 to 3, wherein: The heat transfer plate is formed of a metal material including aluminum.

7. A turbo refrigerator, comprising: The turbo compressor according to any one of claims 1 to 3; a condenser for condensing the refrigerant discharged from the turbo compressor; an expansion valve for adiabatically expanding the refrigerant condensed in the condenser; an evaporator for evaporating the refrigerant adiabatically expanded in the expansion valve; and The refrigerant supply unit can guide the refrigerant condensed in the condenser to the cooling unit.

8. The turbo refrigerator according to claim 7, wherein: The refrigerant supply unit comprises: An introduction pipeline guides the refrigerant to the cooling part; and The regulating valve is provided in the introduction pipe and decompresses the refrigerant flowing in the introduction pipe, thereby making the refrigerant toward the cooling unit into a gas-liquid two-phase state.

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