JP2020193587A - Dynamic compressor, refrigeration cycle device, and method for operating dynamic compressor - Google Patents

Abstract

To provide a technique suitable for suppressing erosion in a compressor.SOLUTION: A dynamic compressor 3 comprises a rotor 27, a refrigerant flow passage 40, a main flow passage 21, and an injection flow passage 24. The rotor 27 includes a rotating shaft 25 and an impeller 26. The rotor 27 is provided with a first interference fitting portion 93 in which the rotating shaft 25 and the impeller 26 are fitted to each other. The refrigerant flow passage 40 is located around the rotor 27, and a vapor phase refrigerant flows therethrough. The main flow passage 21 extends in the axial direction of the rotor 27 inside the rotor 27, and a liquid phase refrigerant flows therethrough. The injection flow passage 24 is located inside the rotor 27, branched from the main flow passage 21 and extends from the main flow passage 21 to the refrigerant flow passage 40 to lead the liquid phase refrigerant from the main flow passage 21 to the refrigerant flow passage 40. The injection flow passage 24 is divided in the middle of the injection flow passage 24 by a partition 99 which is a part of the first interference fitting portion 93, and a gap at the part changes according to the centrifugal force received by the partition 99, so that the partition 99 is opened and closed.SELECTED DRAWING: Figure 2

Description

The present disclosure relates to a speed type compressor, a refrigeration cycle device, and a method of operating the speed type compressor.

As a conventional refrigeration cycle device, a refrigerating system is provided with a two-stage compressor so that the vapor-phase refrigerant discharged from the first-stage compressor is cooled before being sucked into the second-stage compressor. Cycle devices are known.

As shown in FIG. 7, the air conditioner 500 described in Patent Document 1 includes an evaporator 510, a centrifugal compressor 531, a steam cooler 533, a roots compressor 532, and a condenser 520. A centrifugal compressor 531 is provided in the front stage, and a roots type compressor 532 is provided in the rear stage. The evaporator 510 produces a saturated vapor phase refrigerant. The vapor phase refrigerant is sucked into the centrifugal compressor 531 and compressed. The vapor phase refrigerant compressed by the centrifugal compressor 531 is further compressed by the roots compressor 532. The vapor phase refrigerant is cooled in the steam cooler 533 arranged between the centrifugal compressor 531 and the roots compressor 532.

The steam cooler 533 is provided between the centrifugal compressor 531 and the roots compressor 532. In the steam cooler 533, water is sprayed directly onto the vapor phase refrigerant. Alternatively, in the steam cooler 533, heat exchange is indirectly performed between the cooling medium such as air and the gas phase refrigerant.

Japanese Unexamined Patent Publication No. 2008-12202

Patent Document 1 does not study suppressing erosion in a compressor.

This disclosure is
A rotating body including a rotating shaft and an impeller, and provided with a first tightening portion in which the rotating shaft and the impeller are fitted to each other.
A refrigerant flow path located around the rotating body and through which a vapor phase refrigerant flows,
Inside the rotating body, a main flow path extending in the axial direction of the rotating body and through which a liquid phase refrigerant flows,
An injection flow path that is located inside the rotating body, branches off from the main flow path, extends from the main flow path to the refrigerant flow path, and guides the liquid phase refrigerant from the main flow path to the refrigerant flow path. A speed compressor provided with an injection flow path that is partitioned in the middle of the injection flow path by a partition that is a part of the first tightening portion and is opened and closed according to the centrifugal force received by the partition. provide.

According to the present disclosure, erosion in the compressor can be suppressed.

FIG. 1 is a configuration diagram of a refrigeration cycle device according to the first embodiment of the present disclosure. FIG. 2 is a cross-sectional view of the speed type compressor according to the first embodiment of the present disclosure. FIG. 3 is a cross-sectional view of a rotating body along lines III-III. FIG. 4A is a cross-sectional view of the speed type compressor at the time of starting. FIG. 4B is a cross-sectional view of the speed type compressor during rated operation. FIG. 5 is a cross-sectional view of the speed type compressor according to the comparative form 1. FIG. 6 is a flowchart showing an operation method of the speed type compressor of the present disclosure. FIG. 7 is a configuration diagram of a conventional air conditioner.

(Knowledge on which this disclosure was based)
According to the air conditioner described in Patent Document 1, in the steam cooler 533, the degree of superheat of the refrigerant sucked into the roots compressor 532 can be reduced. However, the degree of superheat generated in the compression process of the centrifugal compressor 531 and the degree of superheat generated in the compression process of the roots compressor 532 cannot be removed in the compression process. As the degree of superheat of the refrigerant increases, the enthalpy of the refrigerant also increases.

The ideal compression process in a compressor is along a completely insulated isentropic line. In the mph diagram of the refrigerant, as the enthalpy of the refrigerant increases, the slope of the isentropic line becomes gentler, and a larger compression power is required. As the degree of superheat of the refrigerant increases, a larger compression power is required to raise the pressure of the unit mass of the refrigerant to a predetermined pressure. In other words, the load on the compressor increases and the power consumption of the compressor increases.

Therefore, the present inventors have considered cooling the gas-phase refrigerant by compressing the gas-phase refrigerant in the compression process of the compressor and supplying the liquid-phase refrigerant to the gas-phase refrigerant. Specifically, it was considered to supply the liquid phase refrigerant to the gas phase refrigerant by utilizing the centrifugal force generated by the rotation of the rotating body.

In such a case, when the rotation speed of the rotating body is high, the centrifugal force received by the liquid phase refrigerant is large. Therefore, the liquid phase refrigerant is likely to be atomized. The atomized liquid phase refrigerant easily exchanges heat with the gas phase refrigerant. Therefore, according to the atomized liquid phase refrigerant, the gas phase refrigerant can be easily cooled.

On the other hand, when the rotation speed of the rotating body is low, the centrifugal force received by the liquid phase refrigerant is small. Therefore, the liquid phase refrigerant tends to be in the state of liquid threads or coarse droplets. Liquid phase refrigerants in these states are prone to cause erosion of compressor components, such as impellers.

The present disclosure provides a technique suitable for suppressing erosion in a compressor.

(Summary of one aspect relating to this disclosure)
The speed compressor according to the first aspect of the present disclosure is
A rotating body including a rotating shaft and an impeller, and provided with a first tightening portion in which the rotating shaft and the impeller are fitted to each other.
A refrigerant flow path located around the rotating body and through which a vapor phase refrigerant flows,
Inside the rotating body, a main flow path extending in the axial direction of the rotating body and through which a liquid phase refrigerant flows,
An injection flow path located inside the rotating body, branching from the main flow path and extending from the main flow path to the refrigerant flow path, and guiding the liquid phase refrigerant from the main flow path to the refrigerant flow path. It is provided with an injection flow path that is partitioned in the middle of the injection flow path by a partition that is a part of the first tightening portion and is opened and closed according to the centrifugal force received by the partition.

In the first aspect, the injection flow path is opened and closed according to the centrifugal force received by the partition. According to such a partition, when the rotation speed of the rotating body is low, it is possible to prevent the refrigerant from flowing out from the injection flow path and causing erosion by closing the injection flow path. Further, when the rotation speed of the rotating body is high, the atomized liquid-phase refrigerant and the gas-phase refrigerant can be heat-exchanged by opening the injection flow path.

In the second aspect of the present disclosure, for example, in the speed type compressor according to the first aspect,
The rotating body may be provided with a second tightening portion in which the rotating shaft and the impeller are fitted to each other.
The tightening allowance of the second tightening fitting portion may be larger than the tightening allowance of the first tightening fitting portion.

According to the second aspect, at the time of high-speed rotation of the rotating body, the state in which the rotating shaft and the impeller are fitted by the second tightening fitting portion can be maintained.

In the third aspect of the present disclosure, for example, in the speed type compressor according to the second aspect,
The first tightening portion may be provided at the first position in the axial direction.
The second tightening portion may be provided at the second position in the axial direction.
The diameter of the impeller at the first position may be larger than the diameter of the impeller at the second position.

The impeller is unlikely to be deformed radially outward due to centrifugal force at an axial position having a small diameter, and is easily deformed radially outward due to centrifugal force at an axial position having a large diameter. In the third aspect, the first tightening fitting portion is provided at an axial position where the diameter of the impeller is large, and the second tightening fitting portion is provided at an axial position where the diameter of the impeller is small. This is convenient for the first tightening portion to function as a switch for opening and closing the injection flow path, and the second tightening fitting portion to function as a fixing portion for fixing the rotating shaft and the impeller.

In the fourth aspect of the present disclosure, for example, in the speed type compressor according to any one of the first to third aspects,
In the injection flow path, the first portion, the partition, and the second portion may be arranged in this order from the main flow path to the refrigerant flow path.
The first portion may be provided by using a groove provided on the rotation shaft and / or the outer surface of the impeller.

The injection flow path of the fourth aspect is an example of the injection flow path.

The refrigeration cycle apparatus according to the fifth aspect of the present disclosure is
Evaporator and
A speed compressor according to any one of the first to fourth aspects, and
Condenser and
Is equipped with.

According to the fifth aspect, the same effect as that of the first aspect can be obtained.

The method of operating the speed compressor according to the sixth aspect of the present disclosure is as follows.
It is a method of operating a speed compressor equipped with a rotating body.
Supplying the vapor phase refrigerant to the compression process
When the rotation speed of the rotating body is relatively low, the injection flow path located inside the rotating body is blocked by a partition, whereby the liquid phase refrigerant is supplied to the gas phase refrigerant in the compression process. To ban and
When the rotation speed of the rotating body is relatively high, a centrifugal force is applied to the partition to move the end portion of the partition in the direction of the centrifugal force to release the blockage of the injection flow path. Includes permitting the liquid phase refrigerant to be supplied to the gas phase refrigerant in the compression process.

According to the sixth aspect, when the rotation speed of the rotating body is low, by closing the injection flow path, it is possible to prevent the refrigerant from flowing out from the injection flow path and causing erosion. Further, when the rotation speed of the rotating body is high, the atomized liquid-phase refrigerant and the gas-phase refrigerant can be heat-exchanged by opening the injection flow path.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to this embodiment.

(Embodiment 1)
FIG. 1 shows the configuration of the refrigeration cycle apparatus according to the first embodiment of the present disclosure. The refrigeration cycle device 100 includes an evaporator 2, a compressor 3, a condenser 4, and a refrigerant supply path 11. The compressor 3 is connected to the evaporator 2 by the suction pipe 6 and is connected to the condenser 4 by the discharge pipe 8. Specifically, the suction pipe 6 is connected to the outlet of the evaporator 2 and the suction port of the compressor 3. A discharge pipe 8 is connected to the discharge port of the compressor 3 and the inlet of the condenser 4. The condenser 4 is connected to the evaporator 2 by a return path 9. The evaporator 2, the compressor 3, and the condenser 4 are connected in this order in an annular shape to form the refrigerant circuit 10.

The refrigerant evaporates in the evaporator 2 to generate a vapor phase refrigerant. The vapor phase refrigerant generated by the evaporator 2 is sucked into the compressor 3 through the suction pipe 6 and compressed. The compressed vapor phase refrigerant is supplied to the condenser 4 through the discharge pipe 8. The gas phase refrigerant is cooled in the condenser 4 to generate a liquid phase refrigerant. The liquid phase refrigerant is sent from the condenser 4 to the evaporator 2 through the return path 9. The vapor phase refrigerant may also be referred to as refrigerant vapor. The liquid phase refrigerant may also be referred to as a refrigerant liquid.

As the refrigerant of the refrigeration cycle apparatus 100, a fluorocarbon-based refrigerant, a low GWP (Global Warming Potential) refrigerant, and a natural refrigerant can be used. Examples of chlorofluorocarbon-based refrigerants include HCFC (hydrochlorofluorocarbon) and HFC (hydrofluorocarbon). Examples of the low GWP refrigerant include HFO-1234yf. Examples of natural refrigerants include CO ₂ and water.

The refrigeration cycle device 100 is filled with, for example, a refrigerant containing a substance having a negative saturated vapor pressure at room temperature as a main component. Examples of such a refrigerant include a refrigerant containing water as a main component. The "main component" means the component contained most in the mass ratio. “Room temperature” means a temperature range of 20 ° C. ± 15 ° C. as described in Japanese Industrial Standard JIS Z8703. Negative pressure means pressure that is absolute pressure lower than atmospheric pressure.

When water is used as the refrigerant, the pressure ratio in the refrigeration cycle increases, and the degree of superheat of the refrigerant tends to become excessive. In the present embodiment, the liquid phase refrigerant flows out toward the refrigerant flow path inside the compressor 3, and the increase in the enthalpy of the refrigerant due to the increase in the degree of superheat of the refrigerant in the compression process is continuously suppressed. As a result, the work to be done by the compressor 3 in order to raise the pressure of the refrigerant to a predetermined pressure can be significantly reduced. That is, the power consumption of the compressor 3 can be significantly saved.

The refrigeration cycle device 100 further includes a heat absorption circuit 12 and a heat dissipation circuit 14.

The endothermic circuit 12 is a circuit for using the liquid phase refrigerant cooled by the evaporator 2, and has necessary equipment such as a pump and an indoor heat exchanger. A part of the endothermic circuit 12 is located inside the evaporator 2. Inside the evaporator 2, a part of the endothermic circuit 12 may be located above the liquid level of the liquid phase refrigerant or may be located below the liquid level of the liquid phase refrigerant. The endothermic circuit 12 is filled with a heat medium such as water or brine.

The liquid-phase refrigerant stored in the evaporator 2 comes into contact with the members constituting the endothermic circuit 12. As a result, heat exchange is performed between the liquid phase refrigerant and the heat medium inside the endothermic circuit 12, and the liquid phase refrigerant evaporates. The heat medium inside the endothermic circuit 12 is cooled by the latent heat of vaporization of the liquid phase refrigerant. A typical example of a member constituting the endothermic circuit 12 is a pipe. For example, when the refrigerating cycle device 100 is an air conditioner that cools the room, the air in the room is cooled by the heat medium of the endothermic circuit 12. The indoor heat exchanger is, for example, a fin tube heat exchanger.

The heat dissipation circuit 14 is a circuit used to remove heat from the refrigerant inside the condenser 4, and has necessary equipment such as a pump and a cooling tower. A part of the heat dissipation circuit 14 is located inside the condenser 4. Specifically, inside the condenser 4, a part of the heat dissipation circuit 14 is located above the liquid level of the liquid phase refrigerant. The heat dissipation circuit 14 is filled with a heat medium such as water or brine. When the refrigeration cycle device 100 is an air conditioner for cooling the room, the condenser 4 is arranged outside the room, and the refrigerant of the condenser 4 is cooled by the heat medium of the heat dissipation circuit 14.

The high-temperature vapor-phase refrigerant discharged from the compressor 3 comes into contact with the members constituting the heat dissipation circuit 14 inside the condenser 4. As a result, heat exchange is performed between the vapor phase refrigerant and the heat medium inside the heat dissipation circuit 14, and the vapor phase refrigerant is condensed. The heat medium inside the heat dissipation circuit 14 is heated by the latent heat of condensation of the vapor phase refrigerant. A typical example of a member constituting the heat dissipation circuit 14 is a pipe. The heat medium heated by the vapor phase refrigerant is cooled by outside air or cooling water in a cooling tower (not shown) of the heat dissipation circuit 14, for example.

The evaporator 2 is composed of, for example, a container having heat insulating properties and pressure resistance. The evaporator 2 stores the liquid-phase refrigerant and evaporates the liquid-phase refrigerant internally. The liquid phase refrigerant inside the evaporator 2 absorbs heat generated from the outside of the evaporator 2 and evaporates. That is, the liquid phase refrigerant heated by absorbing heat from the endothermic circuit 12 evaporates in the evaporator 2. In the present embodiment, the liquid phase refrigerant stored in the evaporator 2 indirectly contacts the heat medium circulating in the endothermic circuit 12. That is, a part of the liquid phase refrigerant stored in the evaporator 2 is heated by the heat medium of the endothermic circuit 12, and is used to heat the saturated liquid phase refrigerant. The temperature of the liquid-phase refrigerant stored in the evaporator 2 and the temperature of the vapor-phase refrigerant generated in the evaporator 2 are, for example, 5 ° C.

In this embodiment, the evaporator 2 is an indirect contact type heat exchanger such as a shell tube heat exchanger. However, the evaporator 2 may be a direct contact type heat exchanger such as a spray type or filler type heat exchanger. That is, the liquid phase refrigerant may be heated by circulating the liquid phase refrigerant in the endothermic circuit 12. Further, the endothermic circuit 12 may be omitted.

The compressor 3 sucks in the vapor phase refrigerant generated by the evaporator 2 and compresses it. The compressor 3 is a dynamic compressor. The velocity type compressor is a compressor that increases the pressure of the gas phase refrigerant by giving momentum to the vapor phase refrigerant and then decelerating it. Examples of the speed type compressor include a centrifugal compressor, a mixed flow compressor, and an axial flow compressor. Speed compressors are also called turbo compressors. The compressor 3 may include a variable speed mechanism for changing the rotation speed. An example of a variable speed mechanism is an inverter that drives the motor of the compressor 3. The temperature of the refrigerant at the discharge port of the compressor 3 is, for example, in the range of 100 to 150 ° C.

The condenser 4 is composed of, for example, a container having heat insulating properties and pressure resistance. The condenser 4 condenses the gas-phase refrigerant compressed by the compressor 3 and stores the liquid-phase refrigerant generated by condensing the gas-phase refrigerant. In the present embodiment, the gas phase refrigerant indirectly contacts and condenses the heat medium cooled by releasing heat to the external environment. That is, the gas phase refrigerant is cooled by the heat medium of the heat dissipation circuit 14 and condensed. The temperature of the gas phase refrigerant introduced into the condenser 4 is, for example, in the range of 100 to 150 ° C. The temperature of the liquid phase refrigerant stored in the condenser 4 is, for example, 35 ° C.

In this embodiment, the condenser 4 is an indirect contact type heat exchanger such as a shell tube heat exchanger. However, the condenser 4 may be a direct contact type heat exchanger such as a spray type or filler type heat exchanger. That is, the liquid phase refrigerant may be cooled by circulating the liquid phase refrigerant in the heat dissipation circuit 14. Further, the heat dissipation circuit 14 may be omitted.

The suction pipe 6 is a flow path for guiding the vapor phase refrigerant from the evaporator 2 to the compressor 3. The outlet of the evaporator 2 is connected to the suction port of the compressor 3 via the suction pipe 6.

The discharge pipe 8 is a flow path for guiding the gas phase refrigerant compressed from the compressor 3 to the condenser 4. The discharge port of the compressor 3 is connected to the inlet of the condenser 4 via the discharge pipe 8.

The return path 9 is a flow path for guiding the liquid phase refrigerant from the condenser 4 to the evaporator 2. The evaporator 2 and the condenser 4 are connected by a return path 9. A pump, a flow rate adjusting valve, or the like may be arranged in the return path 9. The return path 9 may consist of at least one pipe.

The refrigerant supply path 11 connects the evaporator 2 and the compressor 3. The liquid phase refrigerant stored in the evaporator 2 is supplied to the compressor 3 through the refrigerant supply path 11. The liquid phase refrigerant flows out toward the refrigerant flow path inside the compressor 3. The refrigerant supply path 11 may be composed of at least one pipe. The inlet of the refrigerant supply path 11 is located below the liquid level of the liquid phase refrigerant stored in the evaporator 2 in the evaporator 2. A pump, a valve, or the like may be arranged in the refrigerant supply path 11.

The refrigeration cycle device 100 may include a spare tank for storing the liquid phase refrigerant. The spare tank is connected to, for example, the evaporator 2. The liquid phase refrigerant is transferred from the evaporator 2 to the spare tank. The refrigerant supply path 11 connects the spare tank and the compressor 3 so that the liquid phase refrigerant is supplied from the spare tank to the compressor 3. The spare tank may be connected to the suction pipe 6. In this case, the spare tank may store the liquid phase refrigerant supplied from within the refrigeration cycle, or stores the liquid phase refrigerant generated by being cooled by an external heat source via the inner peripheral surface of the suction pipe 6 or the like. You may.

Next, the structure of the compressor 3 will be described in detail. In the example according to the following description, the compressor 3 is a centrifugal compressor.

As shown in FIG. 2, the compressor 3 includes a rotating body 27, a housing 35, a shroud 37, a bearing 18, and a nozzle 90. The rotating body 27 is arranged in a space surrounded by the housing 35 and the shroud 37. A motor (not shown) for rotating the rotating body 27 may be arranged inside the housing 35.

The rotating body 27 includes a rotating shaft 25 and an impeller 26. The impeller 26 is attached to the rotating shaft 25 and rotates at high speed together with the rotating shaft 25. The rotation speed of the rotating body 27 is, for example, in the range of 5000 to 100,000 rpm. The rotating shaft 25 is made of a high-strength iron-based material such as S45CH. The impeller 26 is made of, for example, a material such as aluminum, duralumin, iron, ceramic. Although one impeller is shown in FIG. 2, the rotating body 27 may include a plurality of stages of impellers. That is, the rotating body 27 may include at least one impeller.

The impeller 26 has a hub 30 and a plurality of blades 31. The hub 30 is a portion fitted to the rotating shaft 25. In the cross section including the central axis O of the rotating shaft 25, the hub 30 has a divergent contour. The plurality of blades 31 are arranged on the surface 30p of the hub 30 along the circumferential direction of the rotation shaft 25.

The space around the impeller 26 includes a refrigerant flow path 40, a diffuser 41, and a swirl chamber 42. The refrigerant flow path 40 is located around the rotating body 27 and is a flow path through which the vapor phase refrigerant to be compressed flows. The refrigerant flow path 40 includes a suction flow path 36 and a plurality of interblade flow paths 38. The suction flow path 36 is located on the upstream side of the upstream end 31t of the blade 31 in the flow direction of the vapor phase refrigerant. The interblade flow path 38 is located between the blades 31 adjacent to each other in the circumferential direction of the rotation shaft 25. When the impeller 26 rotates, the gas phase refrigerant flowing through each of the plurality of interblade flow paths 38 is given a speed in the rotation direction.

The diffuser 41 is a flow path for guiding the gas phase refrigerant accelerated in the rotational direction by the impeller 26 to the spiral chamber 42. The flow path cross-sectional area of the diffuser 41 expands from the refrigerant flow path 40 toward the spiral chamber 42. This structure slows down the flow velocity of the gas phase refrigerant accelerated by the impeller 26 and raises the pressure of the vapor phase refrigerant. The diffuser 41 is, for example, a vaneless diffuser configured by a flow path extending in the radial direction. In order to effectively increase the pressure of the refrigerant, the diffuser 41 may be a vaned diffuser having a plurality of vanes and a plurality of channels partitioned by them.

The spiral chamber 42 is a spiral space in which the vapor phase refrigerant that has passed through the diffuser 41 is collected. The compressed vapor-phase refrigerant is guided to the outside of the compressor 3, specifically, the discharge pipe 8 via the spiral chamber 42. The cross-sectional area of the spiral chamber 42 expands along the circumferential direction, whereby the flow velocity and the angular momentum of the gas phase refrigerant in the spiral chamber 42 are kept constant.

The shroud 37 covers the impeller 26 and defines the refrigerant flow path 40, the diffuser 41 and the swirl chamber 42. The shroud 37 is made of an iron-based material or an aluminum-based material. Examples of the iron-based material include FC250, FCD400, SS400 and the like. Examples of the aluminum-based material include ACD12.

The housing 35 serves as a casing for accommodating various parts of the compressor 3. The spiral chamber 42 is formed by combining the housing 35 and the shroud 37. The housing 35 can be made of the above-mentioned iron-based material or aluminum-based material. When the diffuser is a vaned diffuser, multiple vanes may also be made of the iron-based or aluminum-based materials described above.

The bearing 18 rotatably supports the rotating shaft 25. In this embodiment, the bearing 18 is a plain bearing. The slide bearing 18 uses the liquid phase refrigerant of the refrigeration cycle device 100 as a lubricant. The plain bearing 18 is connected to the housing 35 either directly or via a bearing box (not shown). The seal 29 prevents the lubricant of the plain bearing 18 from flowing toward the impeller 26. The seal 29 is, for example, a labyrinth seal.

The bearing lubrication flow path 91 is located between the slide bearing 18 and the rotating shaft 25. A liquid phase refrigerant is supplied to the bearing lubrication flow path 91. The slide bearing 18 is lubricated by the liquid phase refrigerant flowing through the bearing lubrication flow path 91. As a result, seizure of the slide bearing 18 can be prevented. The gap between the slide bearing 18 and the rotating shaft 25 can be referred to as a bearing gap. The bearing lubrication flow path 91 is provided in the bearing gap. The liquid-phase refrigerant that lubricates the slide bearing 18 in the bearing lubrication flow path 91 is discharged to the outside of the housing 35 through the discharge flow path 19.

It is not essential that the bearing 18 is a plain bearing. Another example of bearing 18 is a rolling bearing.

A main flow path 21 and an injection flow path 24 are provided inside the rotating body 27.

The main flow path 21 communicates with the bearing lubrication flow path 91. The main flow path 21 extends in the axial direction of the rotating body 27 inside the rotating body 27. The main flow path 21 has an inflow port 21a into which the liquid phase refrigerant is introduced. Specifically, the main flow path 21 is provided inside the rotating shaft 25 and extends in the axial direction of the rotating shaft 25. The injection flow path 24 is located inside the rotating body 27. The injection flow path 24 branches from the main flow path 21 and extends from the main flow path 21 to the refrigerant flow path 40.

The main flow path 21 is connected to the evaporator 2 through the refrigerant supply path 11. The liquid phase refrigerant introduced from the refrigerant supply path 11 located outside the rotating body 27 flows through the main flow path 21. The injection flow path 24 is a flow path that guides the liquid phase refrigerant from the main flow path 21 to the refrigerant flow path 40.

The nozzle 90 is provided in the injection flow path 24. The nozzle 90 causes the liquid phase refrigerant to flow out to the refrigerant flow path 40. Specifically, the nozzle 90 is provided at the tip of the injection flow path 24.

In this embodiment, the nozzle 90 is provided in the injection flow path 24 by screwing. Screwing is suitable for firmly fixing the nozzle 90. Specifically, the nozzle 90 has a nozzle screw 90a which is a threaded portion. The inner surface of the rotating body 27 has a screw hole portion. The nozzle screw 90a is engaged with the screw hole portion. By such engagement, the nozzle 90 is provided in the injection flow path 24. In the illustrated example, the inner surface of the impeller 26 has a threaded hole. However, the inner surface of the rotating shaft 25 may have a screw hole portion.

The nozzle 90 may be provided in the injection flow path 24 by means other than screwing.

In the first alternative example, the nozzle 90 is provided in the injection flow path 24 by fitting. Specifically, the nozzle 90 is provided in the injection flow path 24 by being fitted into the inner surface of the rotating body 27. More specifically, the nozzle 90 is provided in the injection flow path 24 by being fitted into the inner surface of the impeller 26 or the rotating shaft 25.

In the second alternative example, the inner surface of the rotating body 27 has a counterbore portion. Specifically, the inner surface of the impeller 26 or the rotating shaft 25 has a counterbore portion. The nozzle 90 is housed in the counterbore portion. Sealing is done to maintain its containment. In this way, the nozzle 90 is provided in the injection flow path 24.

In the form based on screwing, fitting and counterbore described above, the nozzle 90 is a separate component from the rotating shaft 25 and the impeller 26. However, the nozzle 90 may be a part included in the rotating shaft 25 or the impeller 26.

In a typical example, the nozzle 90 sprays the liquid phase refrigerant into the refrigerant flow path 40. As a result, the atomized liquid-phase refrigerant can flow out to the refrigerant flow path 40. In this way, heat exchange between the liquid phase refrigerant and the gas phase refrigerant is likely to be promoted. Also, in this way, the risk of erosion of the impeller 26 can be reduced.

In the example of FIG. 2, a groove 97 is provided on the outer surface of the impeller 26. A first hole 241 is provided inside the rotating shaft 25. The first hole 241 extends from the main flow path 21 in the radial direction of the rotating shaft 25. A second hole 242 is provided inside the impeller 26. The second hole 242 extends between the rotating shaft 25 and the refrigerant flow path 40. The injection flow path 24 is provided by using the first hole 241 and the groove 97, and the second hole 242. Specifically, in the injection flow path 24, the first hole 241 and the groove 97 and the second hole 242 are arranged in this order from the main flow path 21 toward the refrigerant flow path 40.

The word "injection" in the injection flow path 24 is intended to limit the mode in which the liquid phase refrigerant flows in the injection flow path 24, the mode in which the liquid phase refrigerant flows out from the nozzle 90 to the refrigerant flow path 40, and the like. Not what I did. For example, the flow velocity of the liquid phase refrigerant flowing through the injection flow path 24 is not particularly limited. Further, there are various types of nozzles, and the outflow mode of the liquid thereof is various, but the types of nozzles that can be adopted as the nozzle 90 are not particularly limited.

Hereinafter, the compressor 3 according to the present embodiment will be further described with reference to how the refrigerant flows.

The liquid phase refrigerant is supplied from the evaporator 2 to the main flow path 21 through the refrigerant supply path 11. The liquid-phase refrigerant is pressurized by centrifugal force and flows out toward the refrigerant flow path 40 inside the compressor 3 through the main flow path 21 and the injection flow path 24. When the liquid-phase refrigerant comes into contact with the gas-phase refrigerant in the refrigerant flow path 40, heat exchange occurs between the liquid-phase refrigerant and the gas-phase refrigerant, and the overheated vapor-phase refrigerant continues due to the sensible heat or evaporation latent heat of the liquid-phase refrigerant. Is cooled. As a result, the increase in the enthalpy of the refrigerant due to the increase in the degree of superheat of the refrigerant in the compression process is continuously suppressed. The compression power required by the compressor 3 can be reduced to less than the compression power required for fully insulated isentropic compression. The work that the compressor 3 has to do to raise the pressure of the refrigerant to a predetermined pressure can be significantly reduced. That is, the power consumption of the compressor 3 can be significantly saved. As a result, the efficiency of the refrigeration cycle device 100 is improved.

The main flow path 21 has an inflow port 21a located on the end surface 25c of the rotating shaft 25. The end face 25c is an end face located on the side opposite to the side on which the impeller 26 is located. The liquid phase refrigerant is introduced from the inflow port 21a into the main flow path 21. According to such a configuration, the liquid phase refrigerant can be smoothly delivered to the main flow path 21. The main flow path 21 includes the central axis O of the rotating shaft 25. In the cross section of the rotating shaft 25, the main flow path 21 has, for example, a circular cross-sectional shape. In the cross section of the rotating shaft 25, the center of the main flow path 21 coincides with the central axis O. However, the center of the main flow path 21 may be offset from the central axis O of the rotating shaft 25. In the axial direction of the rotating shaft 25, the main flow path 21 extends to the vicinity of the upper surface 26t of the impeller 26.

The refrigerant supply path 11 may be connected to the connection port 28 of the housing 35. A buffer chamber 35h communicating with the connection port 28 is provided inside the housing 35, and the liquid phase refrigerant is supplied from the refrigerant supply path 11 to the buffer chamber 35h. The end surface 25c of the rotating shaft 25 faces the buffer chamber 35h. That is, the main flow path 21 opens toward the buffer chamber 35h. According to such a configuration, the liquid phase refrigerant can be smoothly sent from the refrigerant supply path 11 to the main flow path 21 via the buffer chamber 35h.

The injection flow path 24 branches from the main flow path 21 and extends in the radial direction of the rotating shaft 25. Centrifugal force acts on the liquid phase refrigerant in the injection flow path 24. The liquid-phase refrigerant flows out to the refrigerant flow path 40 through the nozzle 90 by centrifugal force and is mixed with the vapor-phase refrigerant sucked into the compressor 3. In the present embodiment, the injection flow path 24 extends in a direction perpendicular to the axial direction of the rotating shaft 25. A nozzle 90 is provided in the injection flow path 24, and the nozzle 90 faces the refrigerant flow path 40. The nozzle 90 is located on the upstream side of the upstream end 31t of the blade 31 in the flow direction of the vapor phase refrigerant. According to such a configuration, it is possible to efficiently remove heat from the gas phase refrigerant in the compression process.

The position of the nozzle 90 is not limited to the position shown in FIG. The nozzle 90 may be located on the downstream side of the upstream end 31t of the blade 31 in the flow direction of the vapor phase refrigerant. Further, the nozzle 90 may be located on the upstream side of the upper surface 26t of the impeller 26 in the flow direction of the vapor phase refrigerant. In this case, the nozzle 90 may be located on the side surface of the rotating shaft 25. With these configurations, it is possible to remove heat from the gas phase refrigerant in the compression process.

The flow path cross-sectional area of the injection flow path 24 is smaller than the flow path cross-sectional area of the main flow path 21. According to such a configuration, it is easy to supply a mist-like liquid phase refrigerant to the refrigerant flow path 40.

As shown in FIG. 3, in the present embodiment, a plurality (two or more) injection flow paths 24 are provided. The plurality of injection flow paths 24 extend radially from the main flow path 21. The liquid phase refrigerant flows out from each of the injection flow paths 24 into the refrigerant flow path 40. According to such a configuration, the gas phase refrigerant can be uniformly cooled in the circumferential direction of the rotating shaft 25. However, when the compressor 3 has at least one injection flow path 24, the effect of the present disclosure can be obtained. The injection flow path 24 may extend parallel to the radial direction of the impeller 26 as in the present embodiment, or may extend in a direction inclined with respect to the radial direction.

Specifically, in the example of FIG. 3, the nozzles 90 are arranged at equal angular intervals in the circumferential direction of the rotation shaft 25. The nozzle 90 is located between the blades 31 adjacent to each other in the circumferential direction. The liquid phase refrigerant flows out from each nozzle 90 to each interblade flow path 38 at a uniform flow rate. According to such a configuration, the gas phase refrigerant can be cooled more uniformly in the circumferential direction of the rotating shaft 25. The number of nozzles 90 may be different from the number of interblade flow paths 38 and may be equal to the number of interblade flow paths 38. The nozzle 90 of the injection flow path 24 may have a one-to-one correspondence with the interblade flow path 38.

As described above, the number of nozzles 90 in the compressor 3 is not particularly limited, and may be one or a plurality. In the present specification, one nozzle 90 may be referred to as a first nozzle 90.

When the plurality of blades 31 include a plurality of full blades and a plurality of splitter blades, the nozzle 90 may be located between the full blades and the full blades adjacent to each other in the circumferential direction in the circumferential direction of the rotation shaft 25. .. Alternatively, the nozzle 90 may be located between the full blade and the splitter blade that are adjacent to each other in the circumferential direction. Splitter blades are shorter blades than full blades. The plurality of full blades and the plurality of splitter blades may be alternately arranged on the surface 30p of the hub 30 along the circumferential direction of the rotation shaft 25.

The structure of the compressor 3 of the present disclosure is applicable to each of the multi-stage compressors. The desired effect can be obtained with the compressor of each stage. For example, when the compressor 3 is a multi-stage compressor including a plurality of impellers, an injection flow path 24 is provided in each of the plurality of impellers, and the liquid phase refrigerant can flow out to the refrigerant flow path of each stage.

Returning to FIG. 2, the rotating body 27 is provided with a first fastening fitting portion 93 in which the impeller 26 and the rotating shaft 25 are fitted to each other. Further, in the rotating body 27 of the example of FIG. 2, a second tightening fitting portion 94 in which the impeller 26 and the rotating shaft 25 are fitted to each other is provided.

The injection flow path 24 is partitioned in the middle by the first tightening fitting portion 93. Specifically, the injection flow path 24 is partitioned in the middle by a partition 99. The partition 99 is a part of the first fastening fitting portion 93. The injection flow path 24 is opened and closed according to the centrifugal force received by the partition 99.

It is assumed that, as shown in FIG. 5, there is no partition that partitions the injection flow path 24 in the middle. In this case, when the rotation speed of the rotating body 27 is low, the centrifugal force received by the liquid-phase refrigerant in the injection flow path 24 is small, so that the liquid-phase refrigerant in the state of liquid threads or coarse droplets flows out from the injection flow path 24. easy. Such an outflow tends to cause erosion of components of the compressor 3, such as the impeller 26.

On the other hand, in the form of FIG. 2, the injection flow path 24 is opened and closed according to the centrifugal force received by the partition 99. By doing so, when the rotation speed of the rotating body 27 is low, by closing the injection flow path 24, it is possible to prevent the refrigerant from flowing out from the injection flow path 24 and causing erosion. Further, when the rotation speed of the rotating body 27 is high, the atomized liquid phase refrigerant and the gas phase refrigerant can be heat-exchanged by opening the injection flow path 24.

In the present embodiment, the partition 99 is a portion of the impeller 26 in the first fastening portion 93.

In the present embodiment, when the rotation speed of the rotating body 27 is relatively low, the injection flow path 24 is closed by the partition 99. As a result, it is prohibited to supply the liquid phase refrigerant to the refrigerant flow path 40. In one specific example, when the rotation speed of the compressor 3 is less than the threshold rotation speed, the blocking and the prohibition are performed.

In the present embodiment, when the rotation speed of the rotating body 27 is relatively high, a centrifugal force is applied to the partition 99 to move the end portion of the partition 99 in the direction of the centrifugal force to block the injection flow path 24. To release. As a result, it is permitted to supply the liquid phase refrigerant to the refrigerant flow path 40. In one specific example, when the rotation speed of the compressor 3 is equal to or higher than the threshold rotation speed, the above release and the above permission are performed.

The blockage of the injection flow path 24 and its release will be further described with reference to FIGS. 4A and 4B. FIG. 4A shows the start-up time of the compressor 3. FIG. 4B shows the rated operation of the compressor 3. At the time of startup, the rotation speed of the compressor 3 is relatively low. At the time of rated operation, the rotation speed of the compressor 3 is relatively high.

The liquid phase refrigerant is supplied to the main flow path 21 through the refrigerant supply path 11. The liquid phase refrigerant flowing in the main flow path 21 is pressurized by centrifugal force inside the first hole 241 and supplied to the groove 97.

During low-speed operation shown in FIG. 4A, the centrifugal force acting on the partition 99 is small. Therefore, the partition 99 closes the injection path 24. That is, there is no gap between the impeller 26 and the rotating shaft 25. The partition 99 cuts off the liquid phase refrigerant, and cuts off the supply of the liquid phase refrigerant from the first injection flow path 24a to the second injection flow path 24b.

During high-speed operation shown in FIG. 4B, a centrifugal force of high-speed rotation acts on the partition 99. As a result, the end portion of the partition 99 moves in the direction of the centrifugal force, and the injection path 24 opens. That is, there is a gap between the impeller 26 and the rotating shaft 25. The liquid phase refrigerant in the groove 97 is supplied to the second injection flow path 24b through the gap, is further pressurized by centrifugal force inside the second injection flow path 24b, and is passed through a nozzle 90 provided at the tip of the injection flow path 24. It is atomized. The atomized liquid phase refrigerant flows out toward the refrigerant flow path 40 inside the compressor 3.

In one specific example, at startup, the compressor 3 is accelerated from 0 to 10000 rpm. The rotation speed of the compressor 3 during rated operation is 28,000 rpm. Hereinafter, the rotation speed during rated operation may be referred to as a rated rotation speed.

It is assumed that the impeller 26 is made of aluminum and its density ρ is 2800 kg / m ³ . It is assumed that the Young's modulus E of the impeller 26 is 7.2 × 10 ¹⁰ N / m ² . It is assumed that the Poisson's ratio ν of the impeller 26 is 0.33. It is assumed that the inner radius a of the impeller 26 in the tightening portion Z is 50 mm. The outer radius b of the impeller 26 at the tightening portion Z is 60 mm. Here, the tightening fitting portion Z is the first tightening fitting portion 93 or the second tightening fitting portion 94. At this time, the displacement x in the radial direction at the inner radius a of the impeller 26 can be calculated by the following formula. In the following equation, ω is the rotation speed of the compressor 3.

The increase width of the inner diameter of the impeller 26 is twice the displacement x in the radial direction. When ω = 10000 rpm, the increase width of the inner diameter of the impeller 26 is 2 × x = 18.1 μm. When ω = 28000 rpm, the increase width of the inner diameter of the impeller 26 is 2 × x = 86.4 μm.

It is assumed that the tightening allowance of the first tightening portion 93 is 18.1 μm. In this case, when the rotation speed of the compressor 3 is less than 10000 rpm, the supply of the liquid phase refrigerant from the first injection flow path 24a to the second injection flow path 24b is cut off. Further, in this case, when the rotation speed of the compressor 3 increases to 10000 rpm or more, a gap begins to open between the impeller 26 and the rotating shaft 25, and the first injection flow path 24a and the second injection flow path 24b communicate with each other. A liquid phase refrigerant is supplied. When the rotation speed of the compressor 3 is 10000 rpm, the liquid phase refrigerant at the position of the outer outer diameter b of the impeller 26 has a pressure of about 2 MPa by being pressurized by centrifugal force.

If the tightening allowance of the second tightening portion 94 is made larger than 86.4 μm, there will be a gap between the impeller 26 and the rotating shaft 25 in the second tightening fitting portion 94 even if the rotation speed of the compressor 3 is the rated rotation speed of 28,000 rpm. Not empty. Therefore, the liquid phase refrigerant does not leak to the outside of the impeller 26.

As can be understood from the above description, the rotation speed of the compressor 3 is low when the compressor 3 is started. Therefore, the centrifugal force due to the rotation received by the impeller 26 is small. Therefore, in the first tightening portion 93, a relative displacement in the radial direction does not occur between the impeller 26 and the rotating shaft 25. That is, there is no gap between the impeller 26 and the rotating shaft 25. Therefore, the state in which the first injection flow path 93 and the second injection flow path 94 are cut off is maintained, and the supply of the liquid phase refrigerant from the first injection flow path 24a to the second injection flow path 24b is cut off. .. Therefore, at the time of start-up, even if the rotation speed is low and the pressure due to the centrifugal force is low, the supply of the liquid phase refrigerant is suppressed, and erosion of the impeller 26 is unlikely to occur.

On the other hand, during the rated operation of the compressor 3, the rotation speed of the compressor 3 is high. Therefore, the centrifugal force due to the rotation received by the impeller 26 is large. Therefore, in the first tightening portion 93, a relative displacement in the radial direction occurs between the impeller 26 and the rotating shaft 25. That is, there is a gap between the impeller 26 and the rotating shaft 25. Therefore, the first injection flow path 24a and the second injection flow path 24b communicate with each other, and the liquid phase refrigerant is supplied from the first injection flow path 24a to the second injection flow path 24b. Further, the liquid phase refrigerant is boosted by the centrifugal force of high-speed rotation. As a result, the liquid phase refrigerant atomized at high pressure flows out into the refrigerant flow path 40.

Further, in this example, the tightening allowance of the second tightening fitting portion 94 is larger than the tightening allowance of the first tightening fitting portion 93. Therefore, even if the second tightening fitting portion 94 receives the centrifugal force due to the high-speed rotation during the rated operation, there is no gap between the impeller 26 and the rotating shaft 25. Therefore, the liquid phase refrigerant is unlikely to leak to the outside of the impeller 26.

Returning to FIG. 2, in the present embodiment, the first portion 24a, the partition 99, and the second portion 24b are arranged in this order from the main flow path 21 toward the refrigerant flow path 40. Specifically, in the example of FIG. 2, the injection flow path 24 is divided into a first portion 24a and a second portion 24b by a partition 99. Hereinafter, the first portion 24a may be referred to as a first injection flow path 24a. The second portion 24b may be referred to as a second injection flow path 24b. The first injection flow path 24a branches from the main flow path 21 and extends from the main flow path 21. The second injection flow path 24b extends to the refrigerant flow path 40.

In the present embodiment, a groove 97 is provided on the outer surface of the impeller 26, and the first injection flow path 24a is provided by using the groove 97. However, instead of providing the groove 97 on the outer surface of the impeller 26, the groove X may be provided on the outer surface of the rotating shaft 25, and the first injection flow path 24a may be provided using the groove X. Further, the groove 97 may be provided on the outer surface of the impeller 26, the groove X may be provided on the outer surface of the rotating shaft 25, and the first injection flow path 24a may be provided by using the groove 97 and the groove X.

In the example of FIG. 2, the first injection flow path 24a is provided by using the first hole 241. Further, the second injection flow path 24a is provided by using the second hole 242.

As described above, in the example of FIG. 2, the tightening allowance of the second tightening fitting portion 94 is larger than the tightening allowance of the first tightening fitting portion 93. In this way, when the rotating body 27 is rotated at high speed, the state in which the rotating shaft 25 and the impeller 26 are fitted by the second tightening fitting portion 94 can be maintained.

In the example of FIG. 2, the first tightening fitting portion 93 is provided at the first position p1 in the axial direction AD of the rotating body 27. The second tightening fitting portion 94 is provided at the second position p2 in the axial direction AD. The diameter of the impeller 26 at the first position p1 is larger than the diameter of the impeller 26 at the second position p2. The impeller 26 is unlikely to be deformed radially outward due to centrifugal force at the axial position p2 having a small diameter, and is easily deformed radially outward due to centrifugal force at the axial position p1 having a large diameter. In the example of FIG. 2, the first tightening fitting portion 93 is provided at the axial position p1 where the diameter of the impeller 26 is large, and the second tightening fitting portion 94 is provided at the axial position p2 where the diameter of the impeller 26 is small. There is. This is convenient for the first tightening portion 93 to function as a switch for opening and closing the injection flow path 24, and the second tightening fitting portion 94 to function as a fixing portion for fixing the rotating shaft 25 and the impeller 26. ..

In one example, the first tightening fitting portion 93 and the second tightening fitting portion 94 are portions in which the rotating shaft 25 and the impeller 26 are fitted to each other by heating the impeller 26 and shrink-fitting it onto the rotating shaft 25. In another example, the first tightening fitting portion 93 and the second tightening fitting portion 94 are portions in which the rotating shaft 25 and the impeller 26 are fitted to each other by cooling the rotating shaft 25 and cooling and fitting the rotating shaft 25 to the impeller 26.

In the example of FIG. 2, the rotating body 27 is provided with the seal portion 95. The seal portion 95 prevents the liquid phase refrigerant from leaking from between the impeller 26 and the rotating shaft 25. The sealing portion 95 is, for example, a sealing material such as an O-ring.

In the illustrated example, the seal portion 95 is provided at the third position p3 in the axial direction AD. The diameter of the impeller 26 at the third position p3 is larger than the diameter of the impeller 26 at the first position p1 and the second position p2.

Next, the operation and operation of the refrigeration cycle device 100 according to a specific example will be described.

When the refrigeration cycle device 100 is left for a certain period of time (for example, at night), the temperature inside the refrigeration cycle device 100 (for example, the refrigerant circuit 10) is substantially balanced with the ambient temperature. The pressure inside the refrigeration cycle device 100 is in equilibrium with a particular pressure. When the compressor 3 is started, the pressure inside the evaporator 2 gradually decreases, and the liquid phase refrigerant evaporates by absorbing heat from the heat medium of the endothermic circuit 12 that exchanges heat with the inside air, and a vapor phase refrigerant is generated. .. The vapor-phase refrigerant is sucked into the compressor 3, compressed, and discharged from the compressor 3. The high-pressure gas-phase refrigerant is introduced into the condenser 4, and is condensed by the gas-phase refrigerant dissipating heat to the outside air or the like via the heat dissipation circuit 14, to generate a liquid-phase refrigerant. The liquid phase refrigerant is sent from the condenser 4 to the evaporator 2 through the return path 9.

Inside the compressor 3, the liquid phase refrigerant flows out to the refrigerant flow path 40 through the main flow path 21 and the injection flow path 24. Heat exchange occurs between the gas phase refrigerant whose temperature has risen due to being boosted by the compressor 3 and the atomized liquid phase refrigerant, and the overheated vapor phase refrigerant is continuously cooled by the evaporation of the atomized liquid phase refrigerant. Will be done. The increase in the enthalpy of the refrigerant due to the increase in the degree of superheat of the refrigerant in the compression process is continuously suppressed. The compression power required by the compressor 3 can be reduced to less than the compression power required for fully insulated isentropic compression. The work that the compressor 3 has to do to raise the pressure of the refrigerant to a predetermined pressure can be significantly reduced. That is, the power consumption of the compressor 3 can be significantly saved. As a result, the efficiency of the refrigeration cycle device 100 is improved.

Further, as described above, erosion in the compressor 3 can be suppressed.

FIG. 6 is a flowchart showing an operation method of the speed type compressor 3 provided with the rotating body 27.

In step S1, the vapor phase refrigerant is supplied to the compression process of the compressor 3.

Step S3 is executed when the rotation speed of the rotating body 27 is relatively low. Step S4 is executed when the rotation speed of the rotating body 27 is relatively high. In FIG. 6, when the rotation speed of the rotating body 27 is relatively low, it corresponds to the case of “No” in step S2. When the rotation speed of the rotating body 27 is relatively high, it corresponds to the case of "Yes" in step S2.

In step S3, the injection flow path 24 located inside the rotating body 27 is closed by the partition 99. In step S3, this prohibits the supply of the liquid phase refrigerant to the gas phase refrigerant in the compression process.

In step S4, a centrifugal force is applied to the partition 99 to move the end portion of the partition 99 in the direction of the centrifugal force to release the blockage of the injection flow path 24. In step S4, this allows the liquid phase refrigerant to be supplied to the gas phase refrigerant in the compression process.

As shown in FIG. 6, step S1 and steps S2 to S4 can be executed in parallel.

Even in the case of a multi-stage compressor, the refrigeration cycle apparatus according to the present disclosure can reduce the compression power by continuously reducing the increase in enthalpy during compression, so that cold heat can be generated with high efficiency. Further, according to the refrigeration cycle apparatus according to the present disclosure, erosion in the compressor can be suppressed. The refrigeration cycle apparatus according to the present disclosure can be applied to applications such as central air conditioners for buildings and chillers for process cooling.

2 Evaporator 3 Compressor 4 Condenser 6 Suction pipe 8 Discharge pipe 9 Return path 10 Refrigerant circuit 11 Refrigerant supply path 12 Heat absorption circuit 14 Heat dissipation circuit 18 Bearing 19 Discharge flow path 21 Main flow path 21a Inflow port 24 Injection flow path 24a First Part 24b Second part 25 Rotating shaft 25c End face 26 Impeller 26t Top surface 27 Rotating body 28 Connection port 29 Seal 30 Hub 30p Hub surface 31 Blade 31t Blade upstream end 35 Housing 35h Buffer chamber 36 Suction flow path 37 Shroud 38 Inter-blade flow Road 40 Refrigerant flow path 41 Diffuser 42 Swirling chamber 90 Nozzle 90a Nozzle screw 91 Bearing lubrication flow path 93 1st tightening fitting part 94 2nd tightening fitting part 95 Sealing part 97 Groove 99 Partition 100 Refrigerant cycle device 241 1st hole 242 2nd Hole

Claims (6)

A rotating body including a rotating shaft and an impeller, and provided with a first tightening portion in which the rotating shaft and the impeller are fitted to each other.
A refrigerant flow path located around the rotating body and through which a vapor phase refrigerant flows,
Inside the rotating body, a main flow path extending in the axial direction of the rotating body and through which a liquid phase refrigerant flows,
An injection flow path that is located inside the rotating body, branches off from the main flow path, extends from the main flow path to the refrigerant flow path, and guides the liquid phase refrigerant from the main flow path to the refrigerant flow path. A speed type compressor including an injection flow path that is partitioned in the middle of the injection flow path by a partition that is a part of the first tightening portion and is opened and closed according to the centrifugal force received by the partition. The rotating body is provided with a second tightening portion in which the rotating shaft and the impeller are fitted to each other.
The tightening allowance of the second tightening fitting portion is larger than the tightening allowance of the first tightening fitting portion.
The speed type compressor according to claim 1. The first tightening portion is provided at the first position in the axial direction.
The second tightening portion is provided at a second position in the axial direction.
The diameter of the impeller at the first position is larger than the diameter of the impeller at the second position.
The speed type compressor according to claim 2. In the injection flow path, the first portion, the partition, and the second portion are arranged in this order from the main flow path to the refrigerant flow path.
The first portion is provided by using a groove provided on the rotation shaft and / or the outer surface of the impeller.
The speed compressor according to any one of claims 1 to 3. Evaporator and
The speed compressor according to any one of claims 1 to 4.
Condenser and
Equipped with a refrigeration cycle device. It is a method of operating a speed compressor equipped with a rotating body.
Supplying the vapor phase refrigerant to the compression process
When the rotation speed of the rotating body is relatively low, the injection flow path located inside the rotating body is blocked by a partition, whereby the liquid phase refrigerant is supplied to the gas phase refrigerant in the compression process. To ban and
When the rotation speed of the rotating body is relatively high, a centrifugal force is applied to the partition to move the end portion of the partition in the direction of the centrifugal force to release the blockage of the injection flow path. A method comprising permitting the liquid phase refrigerant to be supplied to the gas phase refrigerant in the compression process.

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