CN113597515A - Turbo refrigerator - Google Patents
Turbo refrigerator Download PDFInfo
- Publication number
- CN113597515A CN113597515A CN202080022372.8A CN202080022372A CN113597515A CN 113597515 A CN113597515 A CN 113597515A CN 202080022372 A CN202080022372 A CN 202080022372A CN 113597515 A CN113597515 A CN 113597515A
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- China
- Prior art keywords
- gas refrigerant
- magnetic bearing
- refrigerant supply
- cooling
- expansion valve
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/04—Shafts or bearings, or assemblies thereof
- F04D29/046—Bearings
- F04D29/048—Bearings magnetic; electromagnetic
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/05—Shafts or bearings, or assemblies thereof, specially adapted for elastic fluid pumps
- F04D29/056—Bearings
- F04D29/058—Bearings magnetic; electromagnetic
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
- F04D—NON-POSITIVE-DISPLACEMENT PUMPS
- F04D29/00—Details, component parts, or accessories
- F04D29/58—Cooling; Heating; Diminishing heat transfer
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F25—REFRIGERATION OR COOLING; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS; MANUFACTURE OR STORAGE OF ICE; LIQUEFACTION SOLIDIFICATION OF GASES
- F25B—REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS
- F25B1/00—Compression machines, plants or systems with non-reversible cycle
- F25B1/04—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type
- F25B1/053—Compression machines, plants or systems with non-reversible cycle with compressor of rotary type of turbine type
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- Engineering & Computer Science (AREA)
- Physics & Mathematics (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Thermal Sciences (AREA)
- Electromagnetism (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
Abstract
The invention provides a turbo refrigerator which can restrain wind loss generated on a rotating shaft of a turbo compressor and can obtain cooling amount required for cooling a magnetic bearing for supporting the rotating shaft. A turbo compressor (3) is provided with: an impeller; a rotating shaft (24) for rotating the impeller; a magnetic bearing (30) that supports the rotating shaft (24); a gas refrigerant supply pipe (14) for supplying a gas refrigerant as a cooling medium from a condenser, which is a high-pressure portion upstream of the expansion valve in the refrigeration cycle, to the magnetic bearing coils (30a, 30 b); and a refrigerant return pipe for guiding the gas refrigerant passing through the magnetic bearing coils (30a, 30b) to an evaporator, which is a low-pressure part on the downstream side of the expansion valve in the refrigeration cycle.
Description
Technical Field
The present invention relates to a turbo refrigerator including a turbo compressor having a rotary shaft supported by a magnetic bearing.
Background
In order to reduce the mechanical losses of the centrifugal compressor, to remove the lubricating oil system, magnetic bearings are applied. In addition to the above advantages, the turbo refrigerator is also suitable for reducing life cycle cost by reducing periodic maintenance items (see patent document 1).
Prior art documents
Patent document
Patent document 1: japanese patent laid-open publication No. 2016-33348
Disclosure of Invention
Technical problem to be solved by the invention
The magnetic bearing includes a coil portion through which a current flows, and the coil portion generates heat by the flow of the current. Since the magnetic bearing supports the rotating shaft rotating at a high speed with a small gap, wind loss occurs as an agitation loss in the small gap portion. In order to prevent overheating of the coil portion, cooling is desired. When a liquid refrigerant having a large heat capacity is used for cooling, the cooling efficiency is high. However, when a liquid having a high density is supplied to the minute gap, wind loss increases, and as a result, there are problems such as a decrease in efficiency of the turbo refrigerator and an obstruction to stable support of the magnetic bearing.
In patent document 1, a liquid refrigerant is supplied to a ceramic bearing and cooled, but the magnetic bearing does not generate heat due to sliding friction as in the case of the ceramic bearing, and therefore, cooling of the magnetic bearing is not disclosed. Although it is disclosed that the gas refrigerant is supplied to the bearing made of the ceramic material, since the low-pressure gas refrigerant evaporated by the evaporator is used, there is a possibility that the gas refrigerant cannot be supplied in an amount necessary for cooling.
The present invention has been made in view of such circumstances, and an object thereof is to provide a turbo refrigerator capable of suppressing wind loss occurring in a rotating shaft of a turbo compressor and obtaining a cooling amount necessary for cooling a magnetic bearing that supports the rotating shaft.
Means for solving the technical problem
A turbo refrigerator according to an aspect of the present invention includes a refrigeration cycle including: a turbo compressor for compressing a refrigerant; a condenser for condensing the refrigerant discharged from the turbo compressor; an expansion valve for expanding the liquid refrigerant discharged from the condenser; and an evaporator that evaporates the refrigerant guided out from the expansion valve, the turbo compressor including: an impeller; a rotating shaft that rotates the impeller; a magnetic bearing supporting the rotating shaft; a gas refrigerant supply path that supplies a gas refrigerant as a cooling medium to the magnetic bearing from a high-pressure portion on an upstream side of the refrigeration cycle from the expansion valve; and a gas refrigerant return path for guiding the gas refrigerant having passed through the magnetic bearing to a low-pressure portion on a downstream side of the refrigeration cycle with respect to the expansion valve.
Since the gas refrigerant is supplied as the cooling medium from the gas refrigerant supply path to the magnetic bearing without being heated by another heat generating element such as a motor, the magnetic bearing can be cooled efficiently. Since the cooling medium is not a liquid refrigerant but a gas refrigerant, wind loss occurring in the rotating shaft can be suppressed.
The gas refrigerant as the cooling medium is guided from the high-pressure portion on the upstream side of the expansion valve to the magnetic bearing through the gas refrigerant return path, and is returned to the low-pressure portion on the downstream side of the expansion valve. Thus, the cooling refrigerant gas can be supplied by effectively utilizing the high-low pressure difference of the refrigeration cycle, and therefore, the gas refrigerant can be easily used as the cooling medium.
In the turbo refrigerator according to one aspect of the present invention, the gas refrigerant supplied from the gas refrigerant supply path passes between the magnetic bearing and the rotary shaft.
Since the gas refrigerant supplied from the gas refrigerant supply path passes between the magnetic bearing and the rotating shaft, wind loss between the magnetic bearing and the rotating shaft can be suppressed.
In the turbo refrigerator according to one aspect of the present invention, the gas refrigerant supply path includes: an axial direction gas refrigerant supply hole formed along the axial direction of the rotary shaft; and a radial gas refrigerant supply hole connected to the axial gas refrigerant supply hole and formed radially outward toward the magnetic bearing.
The gas refrigerant is caused to flow in the axial direction of the rotary shaft through the axial gas refrigerant supply hole, and the gas refrigerant is caused to flow radially outward of the magnetic bearing side through the radial gas refrigerant supply hole. In this way, the structure can be simplified by supplying the gas refrigerant from the rotating shaft side. The gas refrigerant can be supplied from the radial gas refrigerant supply hole by the centrifugal force of the rotary shaft. Thus, the gas refrigerant can be reliably supplied even under operating conditions in which the high-low differential pressure of the turbo refrigerator is low.
In the turbo refrigerator according to one aspect of the present invention, the gas refrigerant is supplied from the gas refrigerant supply path to: a holding portion that holds the magnetic bearing; an auxiliary bearing fixed to the holding portion and provided on a side of the magnetic bearing; and a space surrounded by the holding portion, the magnetic bearing, and the auxiliary bearing.
The gas refrigerant is supplied from the gas refrigerant supply path to a space surrounded by the magnetic bearing, the auxiliary bearing, and the holding portion that holds the magnetic bearing. By supplying the gas refrigerant to the space surrounded in this manner, the gas refrigerant can be first supplied to the side of the magnetic bearing and then can be made to flow between the magnetic bearing and the rotary shaft. This makes it possible to reliably supply the gas refrigerant to the periphery of the magnetic bearing, and to improve the cooling efficiency.
The auxiliary bearing is in contact with the rotating shaft to rotatably support the rotating shaft when the magnetic bearing is not driven due to a failure or the like. As the auxiliary bearing, for example, a ball bearing can be used.
In addition, the turbo refrigerator according to one aspect of the present invention includes a casing cooling unit that supplies a cooling medium to a casing that houses the turbo compressor.
The casing of the turbo compressor is cooled by a casing cooling portion supplied with a cooling medium. The heat generated by the magnetic bearing is conducted to the housing and is cooled by the housing cooling section. The housing thus serves as a heat sink, whereby the cooling capacity of the magnetic bearing can be increased.
As the cooling medium supplied to the case cooling portion, for example, a liquid refrigerant derived from a refrigerant cycle or cooling water supplied from the outside can be used.
Effects of the invention
Since the magnetic bearing is cooled by the gas refrigerant, it is possible to suppress wind loss occurring in the rotating shaft of the turbo compressor and to obtain a cooling amount necessary for cooling the magnetic bearing that supports the rotating shaft.
Drawings
Fig. 1 is a schematic configuration diagram of a turbo refrigerator according to embodiment 1 of the present invention.
Fig. 2 is a longitudinal sectional view of the turbo compressor of fig. 1.
Fig. 3 is a schematic configuration diagram showing a modification of fig. 1.
Fig. 4 is a longitudinal sectional view showing a turbo compressor of a turbo refrigerator according to embodiment 2 of the present invention.
Detailed Description
Embodiments according to the present invention will be described below with reference to the drawings.
[ embodiment 1 ]
An embodiment according to the present invention will be described below with reference to the drawings.
Fig. 1 shows a schematic structure of a turbo refrigerator 1.
The turbo refrigerator 1 includes: a turbo compressor 3 for compressing a refrigerant; a condenser 5 for condensing the high-temperature and high-pressure gas refrigerant compressed by the turbo compressor 3; an expansion valve 7 for expanding the liquid refrigerant from the condenser 5; and an evaporator 9 for evaporating the liquid refrigerant expanded by the expansion valve 7.
The turbo compressor 3 is a centrifugal two-stage compressor including 2 impellers 13a and 13b, and is driven by an electric motor 10 whose rotation speed is controlled by an inverter device not shown. The inverter device controls its output by a control unit, not shown. The number of impellers is not limited, and 1 impeller may be used as the primary compressor.
Inlet guide vanes (not shown) for controlling the flow rate of the sucked refrigerant are provided at the refrigerant suction ports of the impellers 13a and 13b of the turbo compressor 3, and the capacity of the turbo refrigerator 1 can be controlled.
The turbo compressor 3 and the electric motor 10 are accommodated in a casing 12 which is sealed. The case 12 is made of a metal having a high thermal conductivity, for example, a metal such as an aluminum alloy.
The electric motor 10 includes: a rotor 20 rotating around a central axis; and a substantially cylindrical stator 22 provided with a predetermined gap around the rotor 20. The rotational output of the rotor 20 is transmitted to the impellers 13a and 13b via a rotary shaft (rotary shaft) 24.
In the condenser 5, the high-temperature and high-pressure refrigerant discharged from the turbo compressor 3 is condensed. A cooling heat transfer pipe 26 through which cooling water for cooling the refrigerant flows is passed through the condenser 5. The cooling water is discharged to the outside in a cooling tower not shown, and then guided to the condenser 5 again.
The refrigerant throttled by the expansion valve 7 is guided to the evaporator 9 and evaporated therein. Cold water of a rated temperature (for example, 7 c) is obtained by absorbing heat in the evaporator 9. A cold water heat transfer pipe 28 for cooling cold water supplied to an external load is inserted through the evaporator 9.
A liquid refrigerant supply pipe 14 is provided between a lower portion (e.g., bottom portion) of the condenser 5 and the casing 12. The liquid refrigerant stored in the lower portion of the condenser 5 is guided to the casing 12 side through the liquid refrigerant supply pipe 14. Although not shown, the liquid refrigerant supply pipe 14 may be provided with a flow rate adjustment valve for adjusting the flow rate of the liquid refrigerant.
As shown in fig. 1, a gas refrigerant supply pipe (gas refrigerant supply path) 16 is provided between the upper portion of the condenser 5 and the casing 12. The gas refrigerant present in the upper portion of the condenser 5 is guided to the casing 12 side via the gas refrigerant supply pipe 16. Although not shown, the gas refrigerant supply pipe 16 may be provided with a flow rate adjustment valve for adjusting the flow rate of the gas refrigerant. The downstream end of the gas refrigerant supply pipe 16 is connected to an end portion (right end portion in fig. 1) of the casing 12 on the opposite side of the impellers 13a and 13 b.
A refrigerant return pipe (gas refrigerant return path) 18 is provided between the upper portion of the evaporator 9 and the casing 12. The refrigerant in the casing 12 is guided to the upper portion of the evaporator 9 through the refrigerant return pipe 18.
A specific structure of the turbo compressor 3 is shown in fig. 2. The rotary shaft 24 of the turbo compressor 3 is rotatably supported by a magnetic bearing 30.
The electric motor 10 is provided with the 1 st radial magnetic bearing coil 30a of the magnetic bearing 30 on the impeller 13a, 13b side, and the electric motor 10 is provided with the 2 nd radial magnetic bearing coil 30b of the magnetic bearing 30 on the side opposite to the impeller 13a, 13b side. The radial direction of the rotating shaft 24 is supported by the 1 st radial magnetic bearing coil 30a and the 2 nd radial magnetic bearing coil 30 b.
The 1 st radial magnetic bearing coil 30a is fixed and held on the inner peripheral side of the 1 st holding portion 44a fixed to the housing 12. The 1 st holding portion 44a is made of a metal having a good thermal conductivity, for example, a metal such as an aluminum alloy.
The 2 nd radial magnetic bearing coil 30b is fixed and held on the inner peripheral side of the 2 nd holding portion 44b fixed to the housing 12. The 2 nd holding portion 44b is made of a metal having a good thermal conductivity, for example, a metal such as an aluminum alloy.
A 1 st gap sensor G1 that measures the distance (gap) between the rotary shaft 24 and the 1 st radial magnetic bearing coil 30a is provided on the electric motor 10 side of the 1 st radial magnetic bearing coil 30 a. The output of the 1 st gap sensor G1 is sent to the control unit.
A 2 nd gap sensor G2 that measures the interval (gap) between the rotary shaft 24 and the 2 nd radial magnetic bearing coil 30b is provided on the electric motor 10 side of the 2 nd radial magnetic bearing coil 30 b. The output of the 2 nd gap sensor G2 is sent to the control unit.
A 1 st auxiliary bearing (auxiliary bearing) 32a is provided between the 1 st radial magnetic bearing coil 30a and the impellers 13a and 13 b. A 2 nd auxiliary bearing 32b is provided on the side of the 2 nd radial magnetic bearing coil 30b opposite to the impellers 13a, 13 b). The 1 st auxiliary bearing 32a and the 2 nd auxiliary bearing 32b are, for example, ball bearings, and a predetermined gap is provided with respect to the rotary shaft 24 when the magnetic bearing 30 is normally driven. These auxiliary bearings 32a and 32b are rotatably supported in contact with the rotating shaft 24 when the magnetic bearing 30 is not driven due to a failure or the like.
The 1 st auxiliary bearing 32a is fixed and held on the inner peripheral side of the 1 st holding portion 44 a. The 1 st auxiliary bearing 32a and the 1 st radial magnetic bearing coil 30a are separated from each other, and a 1 st space S1 is formed on the inner peripheral side of the 1 st holding portion 44 a.
The 2 nd auxiliary bearing 32b is fixed and held to the 2 nd holding portion 44 b. The 2 nd auxiliary bearing 32b and the 2 nd radial magnetic bearing coil 30b are separated from each other, and a 2 nd space S2 is formed on the inner peripheral side of the 2 nd holding portion 44 b.
A disc 24a is fixed to an end (right end in fig. 2) of the rotary shaft 24 on the side opposite to the impellers 13a and 13 b. A plurality of pairs of thrust magnetic bearing coils 30c are provided on both sides of the circular plate 24 a. The disk 24a is positioned in the thrust direction while being levitated by a plurality of pairs of thrust magnetic bearing coils 30 c. This accurately determines the positions of the rotary shaft 24 and the impellers 13a and 13b in the thrust direction.
As shown in fig. 2, the gas refrigerant supplied from the gas refrigerant supply pipe 16 is guided to the axial gas refrigerant supply hole 17a formed in the central axis direction of the rotary shaft 24. An axial gas refrigerant supply hole 17a is formed from the rear end (right end in fig. 2) of the rotary shaft 24 to the front of the impellers 13a and 13b (more specifically, corresponding to the position between the 1 st radial magnetic bearing coil 30a and the 1 st auxiliary bearing 32 a).
The radial gas refrigerant supply holes 17b1, 17b2 formed radially outward of the rotary shaft 24 are connected to the axial gas refrigerant supply hole 17 a.
The 1 st radial gas refrigerant supply hole 17b1 formed on the impeller 13a, 13b side of the electric motor 10 is provided at a position corresponding to the 1 st radial magnetic bearing coil 30 a. Specifically, the outlet of the 1 st radial gas refrigerant supply hole 17b1 opens into the 1 st space S1 surrounded by the 1 st radial magnetic bearing coil 30a, the 1 st retaining portion 44a, and the 1 st auxiliary bearing retaining portion 45 a. Thereby, the gas refrigerant is supplied from the 1 st radial direction gas refrigerant supply hole 17b1 into the 1 st space S1, the side surface of the 1 st radial magnetic bearing coil 30a is cooled, and the gas refrigerant cools the 1 st radial magnetic bearing coil 30a while passing between the 1 st radial magnetic bearing coil 30a and the rotary shaft 24. The cooled gas refrigerant is discharged to the outside of the casing 12 from the 1 st refrigerant return pipe (gas refrigerant return path) 18 a.
The 2 nd radial gas refrigerant supply hole 17b2 formed on the opposite side of the electric motor 10 from the impellers 13a and 13b is provided at a position corresponding to the 2 nd radial magnetic bearing coil 30 b. Specifically, the outlet of the 2 nd radial gas refrigerant supply hole 17b2 opens into the 2 nd space S2 surrounded by the 2 nd radial magnetic bearing coil 30b, the 2 nd holding portion 44b, and the 2 nd auxiliary bearing 32 b. Thereby, the gas refrigerant is supplied from the 2 nd radial direction gas refrigerant supply hole 17b2 into the 2 nd space S2, the side surface of the 2 nd radial magnetic bearing coil 30b is cooled, and the gas refrigerant cools the 2 nd radial magnetic bearing coil 30b while passing between the 2 nd radial magnetic bearing coil 30b and the rotary shaft 24. The cooled gas refrigerant is discharged from the 1 st refrigerant return pipe 18a to the outside of the casing 12.
The downstream end of the liquid refrigerant supply pipe 14 is connected to a cooling jacket (casing cooling portion) 15 provided in the casing 12. The cooling jacket 15 is provided around the stator 22 and has a space through which a liquid refrigerant flows. The cooling jacket 15 is disposed in the axial direction of the stator 22. The cooling jacket 15 is used to cool not only the stator 22 but also the housing 12 in the vicinity of the cooling jacket 15 by heat conduction.
The refrigerant that has passed through the cooling jacket 15 to cool the stator 22 is discharged from the 2 nd refrigerant return pipe 18b to the outside of the casing 12.
The control Unit includes, for example, a CPU (Central Processing Unit), a RAM (random Access Memory), a ROM (Read Only Memory), a computer-readable storage medium, and the like. Further, as an example, a series of processes for realizing various functions are stored in a storage medium or the like in the form of a program, and the program is read out to a RAM or the like by a CPU and is executed to perform processing and arithmetic processing of information, thereby realizing various functions. The program may be installed in advance in a ROM or another storage medium, provided in a state of being stored in a computer-readable storage medium, distributed via a wired or wireless communication means, or the like. The computer-readable storage medium refers to a magnetic disk, an optical magnetic disk, a CD-ROM, a DVD-ROM, a semiconductor memory, or the like.
< operation of the turbo refrigerator 1 >
Next, the operation of the turbo refrigerator 1 configured as described above will be described.
The turbo compressor 3 sucks the gas refrigerant from the evaporator 9 and compresses the gas refrigerant by the impellers 13a and 13 b. The compressed gas refrigerant is sent to the condenser 5 and condensed by removing the condensation heat by the cooling heat transfer pipe 26. The condensed liquid refrigerant flows to the expansion valve 7.
The liquid refrigerant flowing to the expansion valve 7 is expanded by the expansion valve 7 and then sent to the evaporator 9. In the evaporator 9, the liquid refrigerant is evaporated and gasified by absorbing latent heat of evaporation from cold water flowing in the cold water heat transfer pipe 28. The thus cooled cold water is sent to an external load not shown. The gas refrigerant vaporized in the evaporator 9 is sent to the turbo compressor 3 again.
< cooling with gaseous refrigerant >
The cooling by the gas refrigerant guided from the gas refrigerant supply pipe 16 to the turbo compressor 3 is performed in the following manner.
The high-pressure gas refrigerant is sent from the condenser 5 to the axial gas refrigerant supply hole 17a formed in the rotary shaft 24 via the gas refrigerant supply pipe 16. The gas refrigerant flowing through the axial direction gas refrigerant supply hole 17a is guided to the 1 st space S1 through the 1 st radial direction gas refrigerant supply hole 17b1, and is guided to the 2 nd space S2 through the 2 nd radial direction gas refrigerant supply hole 17b 2. The gas refrigerant passes through the 1 st space S1 and between the 1 st radial magnetic bearing coil 30a and the rotary shaft 24, thereby cooling the 1 st radial magnetic bearing coil 30 a. The gas refrigerant passes through the 2 nd space S2 and between the 2 nd radial magnetic bearing coil 30b and the rotary shaft 24, thereby cooling the 2 nd radial magnetic bearing coil 30 b.
The gas refrigerant having finished cooling the magnetic bearing coils 30a and 30b flows back to the evaporator 9 at a low pressure through the 1 st refrigerant return pipe 18 a.
< liquid refrigerant Cooling >
The cooling by the liquid refrigerant guided from the liquid refrigerant supply pipe 14 to the turbo compressor 3 is performed in the following manner.
The high-pressure liquid refrigerant is sent from the condenser 5 to a cooling jacket 15 provided in the casing 12 via a liquid refrigerant supply pipe 14. The liquid refrigerant flowing into the cooling jacket 15 absorbs heat of the stator 22, and cools the electric motor 10. At the same time, the housing 12 is also cooled by the refrigerant, and therefore the 1 st radial magnetic bearing coil 30a held by the 1 st holding portion 44a and the 2 nd radial magnetic bearing coil 30b held by the 2 nd holding portion 44b are also cooled.
The refrigerant having finished being cooled in the cooling jacket 15 is returned to the evaporator 9 set to a low pressure via the 2 nd refrigerant return pipe 18 b.
According to the present embodiment, the following operational effects are achieved.
Since the gas refrigerant is supplied as the cooling medium from the gas refrigerant supply pipe 16 to the magnetic bearing coils 30a and 30b, the magnetic bearing coils 30a and 30b can be cooled efficiently. Since the gas refrigerant is used as the cooling medium, not the liquid refrigerant, the wind loss generated in the rotary shaft 24 can be suppressed.
The gas refrigerant as the cooling medium is guided from the condenser 5, which is a high-pressure portion on the upstream side of the expansion valve 7, to the magnetic bearing coils 30a and 30b through the 1 st refrigerant return pipe 18a, and is returned to the evaporator 9, which is a low-pressure portion on the downstream side of the expansion valve 7. This makes it possible to effectively utilize the high-low pressure difference of the refrigeration cycle, and therefore, the gas refrigerant can be easily used as the cooling medium.
Since the gas refrigerant supplied from the gas refrigerant supply pipe 16 passes between the magnetic bearing coils 30a and 30b and the rotary shaft 24, wind loss between the magnetic bearing coils 30a and 30b and the rotary shaft 24 can be suppressed.
The gas refrigerant is caused to flow in the axial direction of the rotary shaft 24 through the axial gas refrigerant supply hole 17a, and the gas refrigerant is caused to flow radially outward of the magnetic bearing coils 30a, 30b through the radial gas refrigerant supply holes 17b1, 17b 2. By supplying the gas refrigerant from the rotary shaft 24 side in this manner, the structure can be simplified. The gas refrigerant can be supplied from the radial gas refrigerant supply holes 17b1 and 17b2 by the centrifugal force of the rotary shaft 24. Thus, the gas refrigerant can be reliably supplied even under operating conditions in which the high-low differential pressure of the turbo refrigerator is low.
The cooling gas refrigerant is supplied to the spaces S1, S2 surrounded by the holding portions 44a, 44b holding the magnetic bearing coils 30a, 30b, and the auxiliary bearings 32a, 32 b. By supplying the gas refrigerant to the spaces S1 and S2 thus surrounded, the gas refrigerant can be first supplied to the sides of the magnetic bearing coils 30a and 30b, and then the gas refrigerant can be made to flow between the magnetic bearing coils 30a and 30b and the rotary shaft 24. This enables the gas refrigerant to be reliably supplied to the surroundings of the magnetic bearing coils 30a and 30b, and the cooling efficiency can be improved.
The casing 12 of the turbocompressor 3 is cooled by a cooling jacket 15 supplied with a cooling medium. The heat generated by the magnetic bearing coils 30a, 30b is conducted to the housing 12 and is cooled by the cooling jacket 15. The case 12 is thus used as a heat sink, whereby the cooling capability of the magnetic bearing coils 30a, 30b can be increased.
< modification example >
This embodiment can be modified as follows.
As shown in fig. 3, a two-stage expansion refrigerant circuit having an intercooler 40 may be provided instead of the configuration shown in fig. 1. A 1 st expansion valve 7a is provided between the intercooler 40 and the condenser 5, and a 2 nd expansion valve 7b is provided between the intercooler 40 and the evaporator 9. An intermediate-pressure gas refrigerant pipe 42 is provided to connect the intercooler 40 and the suction side of the second-stage impeller 13 b. In the present modification, the liquid refrigerant supply pipe 14 'and the gas refrigerant supply pipe 16' are guided from the intercooler 40 to the casing 12.
< embodiment 2 >
As shown in fig. 4, the gas refrigerant supply pipe 16 (see fig. 1) branches into a 1 st gas refrigerant supply pipe 16a and a 2 nd gas refrigerant supply pipe 16 b. The 1 st gas refrigerant supply pipe 16a is connected to a 1 st gas refrigerant supply hole 46a formed in the 1 st holding portion 44 a. The outlet of the 1 st gas refrigerant supply hole 46a opens to the 1 st space S1. The 2 nd gas refrigerant supply pipe 16b is connected to the 2 nd gas refrigerant supply hole 46b formed in the 2 nd holding portion 44 b. The outlet of the 2 nd gas refrigerant supply hole 46b opens to the 2 nd space S2.
According to the present embodiment, it is not necessary to form holes in the rotary shaft 24 as in embodiment 1, and only the gas refrigerant supply holes 46a and 46b need to be formed in the holding portions 44a and 44b, which facilitates machining.
In each of the above embodiments, the liquid refrigerant is used as the cooling medium supplied to the cooling jacket 15, but the present invention is not limited to this, and for example, cooling water supplied from the outside of the turbo compressor 3 may be used.
Description of the symbols
1-a turbo refrigerator, 3-a turbo compressor, 5-a condenser, 7-an expansion valve, 7 a-the 1 st expansion valve, 7 b-the 2 nd expansion valve, 9-an evaporator, 10-an electric motor, 12-a casing, 13a, 13 b-an impeller, 14 '-a liquid refrigerant supply pipe, 15-a cooling jacket (a casing cooling part), 16' -a gas refrigerant supply pipe (a gas refrigerant supply path), 16 a-the 1 st gas refrigerant supply pipe, 16 b-the 2 nd gas refrigerant supply pipe, 17 a-an axial direction gas refrigerant supply hole, 17b 1-the 1 st radial direction gas refrigerant supply hole, 17b 2-the 1 st radial direction gas refrigerant supply hole, 18 a-the 1 st refrigerant return pipe (a gas refrigerant return path), 18 b-2 nd refrigerant return piping, 20-rotor, 22-stator, 24-rotation shaft (rotating draft), 24 a-circular plate, 26-cooling heat transfer pipe, 28-cold water heat transfer pipe, 30-magnetic bearing, 30 a-1 st radial magnetic bearing coil, 30 b-2 nd radial magnetic bearing coil, 30 c-thrust magnetic bearing coil, 32 a-1 st auxiliary bearing (auxiliary bearing), 32 b-2 nd auxiliary bearing (auxiliary bearing), 40-intercooler, 42-intermediate pressure gas refrigerant piping, 44 a-1 st holding part, 44 b-2 nd holding part, G1-1 st gap sensor, G2-2 nd gap sensor, S1-1 st space, S2-2 nd space.
Claims (5)
1. A turbo refrigerator is provided with a refrigeration cycle having: a turbo compressor for compressing a refrigerant; a condenser for condensing the refrigerant discharged from the turbo compressor; an expansion valve for expanding the liquid refrigerant discharged from the condenser; and an evaporator for evaporating the refrigerant guided from the expansion valve,
the turbo compressor includes:
an impeller;
a rotating shaft that rotates the impeller;
a magnetic bearing supporting the rotating shaft;
a gas refrigerant supply path that supplies a gas refrigerant as a cooling medium to the magnetic bearing from a high-pressure portion on an upstream side of the refrigeration cycle from the expansion valve; and
and a gas refrigerant return path that guides the gas refrigerant having passed through the magnetic bearing to a low-pressure portion on a downstream side of the refrigeration cycle with respect to the expansion valve.
2. The turbo refrigerator according to claim 1,
the gas refrigerant supplied from the gas refrigerant supply path passes between the magnetic bearing and the rotary shaft.
3. The turbo refrigerator according to claim 1 or 2,
the gas refrigerant supply path includes: an axial direction gas refrigerant supply hole formed along the axial direction of the rotary shaft; and a radial gas refrigerant supply hole connected to the axial gas refrigerant supply hole and formed radially outward toward the magnetic bearing.
4. The turbo refrigerator according to any one of claims 1 to 3,
the gas refrigerant is supplied from the gas refrigerant supply path to:
a holding portion that holds the magnetic bearing;
an auxiliary bearing fixed to the holding portion and provided on a side of the magnetic bearing; and
a space surrounded by the holding portion, the magnetic bearing, and the auxiliary bearing.
5. The centrifugal chiller according to any one of claims 1 to 4, comprising a casing cooling unit that supplies a cooling medium to a casing that houses the turbo compressor.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019058633A JP7271254B2 (en) | 2019-03-26 | 2019-03-26 | turbo chiller |
| JP2019-058633 | 2019-03-26 | ||
| PCT/JP2020/010470 WO2020195816A1 (en) | 2019-03-26 | 2020-03-11 | Turbo refrigerator |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113597515A true CN113597515A (en) | 2021-11-02 |
Family
ID=72610102
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202080022372.8A Pending CN113597515A (en) | 2019-03-26 | 2020-03-11 | Turbo refrigerator |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP7271254B2 (en) |
| CN (1) | CN113597515A (en) |
| WO (1) | WO2020195816A1 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US11808279B1 (en) * | 2020-03-31 | 2023-11-07 | Daikin Industries, Ltd. | Centrifugal compressor |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP7460923B2 (en) * | 2022-03-28 | 2024-04-03 | ダイキン工業株式会社 | Rotary Fluid Machinery |
| WO2023201220A1 (en) * | 2022-04-12 | 2023-10-19 | Chart Energy & Chemicals, Inc. | Cryogenic expansion turbine with magnetic bearings |
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| JP2006105346A (en) * | 2004-10-08 | 2006-04-20 | Mitsubishi Heavy Ind Ltd | System and method for preventing shaft vibration of rotating machine |
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| JP2014119083A (en) * | 2012-12-19 | 2014-06-30 | Daikin Ind Ltd | Magnetic bearing device and compressor |
| CN105121860A (en) * | 2013-05-30 | 2015-12-02 | 三菱重工业株式会社 | Turbo compressor and turbo chiller using same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| US11808279B1 (en) * | 2020-03-31 | 2023-11-07 | Daikin Industries, Ltd. | Centrifugal compressor |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2020159263A (en) | 2020-10-01 |
| JP7271254B2 (en) | 2023-05-11 |
| WO2020195816A1 (en) | 2020-10-01 |
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