JP2020186705A - Speed type compressor, refrigeration cycle device, and operation method of speed type compressor - Google Patents

Abstract

To provide a technology that is suitable for supporting a rotating body with a bearing.SOLUTION: In a speed type compressor, a rotating body 27 includes a rotary shaft 25 and an impeller 26. A refrigerant flow passage 40 is located around the rotating body 27, and a gas phase refrigerant flows therein. A slide bearing 18 rotatably supports the rotating body 27. A bearing lubrication flow passage 91 is located between the slide bearing 18 and the rotary shaft 25, and a liquid phase refrigerant is supplied thereto. A main flow passage 21 communicates with the bearing lubrication flow passage 91, extends in an axial direction of the rotating body 27 in the rotating body 27, and has an inflow port 21a into which the liquid phase refrigerant is introduced. An injection flow passage 24 is located in the rotating body 27, branches from the main flow passage 21, extends from the main flow passage 21 to the refrigerant flow passage 40, and guides the liquid phase refrigerant from the main flow passage 21 to the refrigerant flow passage 40. The injection flow passage 24 is provided with a first nozzle 90 from which the liquid phase refrigerant flows to the refrigerant flow passage 40. The speed type compressor is provided with a first contracted flow passage 92 through which the liquid phase refrigerant goes between the inflow port 21a and the first nozzle 90.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 two-stage compressor is provided, and the gas 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. 6, 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

In compressors, bearings may support the rotating body. Patent Document 1 does not study the support of a rotating body by bearings.

This disclosure is
A rotating body including a rotating shaft and an impeller,
A refrigerant flow path located around the rotating body and through which a vapor phase refrigerant flows,
A plain bearing that rotatably supports the rotating body,
A bearing lubrication flow path located between the plain bearing and the rotating shaft and to which a liquid phase refrigerant is supplied,
A main flow path that communicates with the bearing lubrication flow path, extends in the axial direction of the rotating body inside the rotating body, and has an inflow port into which the liquid phase refrigerant is introduced.
A flow path that is located inside the rotating body, branches 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. The refrigerant flow path is provided with an injection flow path provided with a first nozzle for flowing out the liquid phase refrigerant.
Provided is a speed type compressor in which a first throttle flow path through which the liquid phase refrigerant passes is provided between the inflow port and the first nozzle.

According to the present disclosure, it is difficult for the slide bearing to run out of liquid phase refrigerant. As a result, seizure of the slide bearing can be avoided. Therefore, the technique according to the present disclosure is suitable for supporting a rotating body with bearings.

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. 4 is a cross-sectional view of the speed type compressor according to the comparative form 1. FIG. 5 is a flowchart showing an operation method of the speed type compressor of the present disclosure. FIG. 6 is a block diagram of a conventional air conditioner.

(Findings underlying this disclosure)
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.

Further, in a compressor, a rotating body may be supported by bearings.

Therefore, the present inventors have considered compressing the vapor-phase refrigerant in the compression process of the compressor and cooling the vapor-phase refrigerant with the liquid-phase refrigerant flowing out of the nozzle. Furthermore, the present inventors have considered using the liquid-phase refrigerant as a lubricant when supporting a rotating body with a slide bearing. In doing so, the liquid phase refrigerant is supplied to both the gas phase refrigerant and the bearings. Therefore, if the nozzle mounting state is defective, dropped, or damaged, a large amount of the liquid phase refrigerant may flow into the gas phase refrigerant, and conversely, the liquid phase refrigerant may be insufficient in the slide bearing. Insufficient liquid phase refrigerant in plain bearings can cause seizure in plain bearings.

The present disclosure provides a technique suitable for preventing the slide bearing from seizing due to a shortage of liquid phase refrigerant in the slide bearing.

(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,
A refrigerant flow path located around the rotating body and through which a vapor phase refrigerant flows,
A plain bearing that rotatably supports the rotating body,
A bearing lubrication flow path located between the plain bearing and the rotating shaft and to which a liquid phase refrigerant is supplied,
A main flow path that communicates with the bearing lubrication flow path, extends in the axial direction of the rotating body inside the rotating body, and has an inflow port into which the liquid phase refrigerant is introduced.
A flow path that is located inside the rotating body, branches 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. The refrigerant flow path is provided with an injection flow path provided with a first nozzle for flowing out the liquid phase refrigerant.
A first throttle flow path through which the liquid phase refrigerant passes is provided between the inflow port and the first nozzle.

In the first aspect, the first throttle flow path is provided between the inflow port of the main flow path and the first nozzle. Therefore, it is easy to avoid a situation in which a large amount of liquid-phase refrigerant flows through the injection flow path even if a defect, dropout, or damage occurs in the mounting state of the first nozzle. Therefore, it is possible to prevent the slide bearing from seizing due to a shortage of the liquid phase refrigerant in the slide bearing.

In the second aspect of the present disclosure, for example, in the speed type compressor according to the first aspect,
The first nozzle may be provided in the injection flow path by screwing.

The second aspect is suitable for firmly fixing the first nozzle.

In the third aspect of the present disclosure, for example, in the speed type compressor according to the first or second aspect,
The number of nozzles for discharging the liquid phase refrigerant flowing from the first throttle flow path to the refrigerant flow path may be N.
The cross-sectional area of the first throttle flow path may be equal to or larger than the specific cross-sectional area of the N nozzles.
Here, the N nozzles include the first nozzle. N is a natural number of 1 or more. When N = 1, the specific cross-sectional area is the cross-sectional area of the minimum flow path of the first nozzle. When N ≧ 2, the specific cross-sectional area is the sum of the cross-sectional areas of the minimum flow paths of the N nozzles.

The third aspect is suitable for avoiding a situation in which sufficient liquid phase refrigerant does not flow to the nozzle due to cavitation.

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,
The throttle flow path may be provided in the main flow path.

According to the fourth aspect, the throttle flow path can be provided on the central axis of the rotating body or at a position close to the central axis. This is advantageous from the viewpoint of equalizing the mass distribution in the circumferential direction of the rotating body and suppressing the vibration of the rotating body.

In the fifth aspect of the present disclosure, for example, in the speed type compressor according to any one of the first to fourth aspects,
The first nozzle may spray the liquid phase refrigerant into the refrigerant flow path.

According to the fifth aspect, the atomized liquid phase refrigerant can flow out to the refrigerant flow path. In this way, heat exchange between the liquid phase refrigerant and the gas phase refrigerant is likely to be promoted.

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

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

The method of operating the speed compressor according to the seventh aspect of the present disclosure is as follows.
A method of operating a speed compressor including a rotating body and a slide bearing that rotatably supports the rotating body.
Performing the first supply to supply the gas phase refrigerant to the compression process,
Performing a second supply to supply the liquid phase refrigerant to the slide bearing, and
A third supply of the liquid phase refrigerant to the gas phase refrigerant in the compression process is included.
The third supply is
Inflowing the liquid phase refrigerant into the rotating body and
By reducing the flow rate of the liquid phase refrigerant that has flowed into the rotating body,
The liquid phase refrigerant having a reduced flow rate is supplied to the gas phase refrigerant in the compression process via the first nozzle.

In the seventh aspect, the liquid phase refrigerant flowing into the inside of the rotating body is supplied to the gas phase refrigerant in the compression process via the first nozzle after the flow rate is throttled. Therefore, it is easy to avoid a situation in which a large amount of liquid-phase refrigerant flows through the injection flow path even if a defect, dropout, or damage occurs in the mounting state of the first nozzle. Therefore, it is possible to prevent the slide bearing from seizing due to a shortage of the liquid phase refrigerant in the slide bearing.

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 in 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. “Normal 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 heat absorbing 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 refrigerating cycle device 100 is an air conditioner that cools 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 the heat provided 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 produced 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 slide 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 impeller 26 may be integrally formed 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 plain bearing 18 rotatably supports the rotating shaft 25. 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 bearing 18 in the bearing lubrication flow path 91 is discharged to the outside of the housing 35 through the discharge flow path 19.

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.

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.

In the present embodiment, the injection flow path 24 includes a first portion 241 and a second portion 242. The first portion 241 is a portion inside the rotating shaft 25 that extends from the main flow path 21 in the radial direction of the rotating shaft 25. The second portion 242 is a portion located between the first portion 241 and the refrigerant flow path 40. The first portion 241 is located inside the rotating shaft 25. The second portion 242 is located inside the impeller 26. According to such a configuration, a sufficient length of the injection flow path 24 can be secured. The longer the injection flow path 24, the greater the centrifugal acceleration applied to the liquid phase refrigerant, and the liquid phase refrigerant tends to flow out to the refrigerant flow path 40. When the tip of the rotating shaft 25 projects axially from the upper surface 26t of the impeller 26, a component different from the impeller 26 may be attached to the tip of the rotating shaft 25, and a second portion inside the component. 242 may be located.

When the nozzle 90 is located upstream of the upper surface 26t of the impeller 26, the second portion 242 may be omitted and the injection flow path 24 may be composed of only the first portion 241.

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.

In the present embodiment, the rotating shaft 25 is fitted to the impeller 26 without a gap by a method such as shrink fitting or cold fitting. As a result, it is possible to prevent the liquid phase refrigerant from leaking from the connecting portion between the first portion 241 and the second portion 242 of the injection flow path 24. A seal structure such as a seal ring may be provided to prevent leakage.

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 compressor 3 is provided with at least one throttle flow path 92 through which the liquid phase refrigerant passes between the inflow port 21a and the nozzle 90. That is, at least one throttle flow path 92 is provided in the flow path of the liquid phase refrigerant between the inflow port 21a of the main flow path 21 and the nozzle 90. The throttle flow path 92 is an element different from the nozzle 90. In the present specification, one throttle flow path 92 may be referred to as a first throttle flow path 92.

It is assumed that the throttle flow path 92 is not provided as shown in FIG. In this case, if the nozzle 90 is not attached properly, falls off, or is damaged, a large amount of liquid phase refrigerant may flow through the injection flow path 24. If a large amount of liquid-phase refrigerant flows into the refrigerant flow path 40 through the injection flow path 24, the liquid-phase refrigerant may be insufficient or depleted in the slide bearing 18, and the slide bearing 18 may be seized. When the nozzle 90 is a nozzle screw 90a, a possible problem in the mounting state is loosening of the nozzle screw 90a or the like. When the nozzle 90 is a nozzle screw 90a, the nozzle 90 may be torn by centrifugal force.

On the other hand, in the compressor 3 of FIG. 2, the throttle flow path 92 is provided. Therefore, even if the nozzle 90 is in a defective state, falls off, or is damaged, it is easy to avoid a situation in which a large amount of liquid phase refrigerant flows through the injection flow path 24. Therefore, it is possible to prevent the slide bearing 18 from seizing due to insufficient liquid phase refrigerant.

The throttle flow path 92 may be provided in, for example, the main flow path 21 or the injection flow path 24.

In the example of FIG. 2, the throttle flow path 92 is provided in the main flow path 21. In this way, the throttle flow path 92 can be provided on the central axis O or at a position close to the central axis O. This is advantageous from the viewpoint of equalizing the mass distribution of the rotating body 27 in the circumferential direction and suppressing the vibration of the rotating body 27.

In the example of FIG. 2, the compressor 3 includes a tubular body 95. The throttle flow path 92 is provided in the tubular body 95. Then, the tubular body 95 is inserted inside the rotating shaft 25. In one specific example, the rotating shaft 25 has a main body portion and a cap portion. The main flow path 21 penetrates the inside of the main body. The cap portion is attached to the main body portion so that the main flow path 21 is closed by the cap portion. In this specific example, the rotating shaft 25 can be assembled by inserting the tubular body 95 into the main body and then attaching the cap to the main body.

The throttle flow path 92 may be provided in the injection flow path 24. When the number of injection flow paths 24 is plural, each of the plurality of injection flow paths 24 may be provided in the throttle flow path 92. The throttle flow path 92 may be provided in one or more of the plurality of injection flow paths 24 instead of each of the plurality of injection flow paths 24. When the number of injection flow paths 24 is one, the injection flow path 24 may be provided in the throttle flow path 92.

In an example of the case where the throttle flow path 92 is provided in the injection flow path 24, the throttle flow path 92 is provided in the tubular body. In this example, the throttle flow path 92 and the nozzle 90 are provided by inserting the tubular body into the inside of the rotating body 27, specifically, the inside of the impeller 26 or the rotating shaft 25, and then providing the nozzle 90 in the injection flow path 24. be able to.

As can be understood from the above description, the throttle flow path 92 may be provided by a separate component from the rotating shaft 25 and the impeller 26. The above-mentioned cylinder corresponds to the above-mentioned separate parts. However, the throttle flow path 92 may be a part included in the rotating shaft 25 or the impeller 26.

It is assumed that the number of nozzles 90 for flowing out the liquid phase refrigerant flowing from the first throttle flow path 92 to the refrigerant flow path 40 is N. In one example, the cross-sectional area of the first throttle flow path is equal to or greater than the specific cross-sectional area of the N nozzles 90. This example is suitable for avoiding a situation in which sufficient liquid phase refrigerant does not flow to the nozzle 90 due to cavitation. Here, when N = 1, the specific cross-sectional area is the cross-sectional area of the minimum flow path of one nozzle 90. When N ≧ 2, the specific cross-sectional area is the sum of the cross-sectional areas of the minimum flow paths of the N nozzles 90. The cross-sectional area of the throttle flow path 92 refers to the cross-sectional area of the portion of the throttle flow path 92 having the smallest cross-sectional area. The cross-sectional area of the minimum flow path of the nozzle 90 refers to the cross-sectional area of the portion of the flow path of the nozzle 90 that has the smallest cross-sectional area.

In one specific example, the main flow path 21 is provided with the first throttle flow path 92. One nozzle 90 is provided in each of the injection flow paths 24. The cross-sectional area of the first throttle flow path 92 is equal to or greater than the total cross-sectional area of the minimum flow paths of the nozzles 90 provided in each injection flow path 24.

In another specific example, one throttle flow path 92 is provided in each of the injection flow paths 24, and one nozzle 90 is provided on the downstream side of the throttle flow path 92. In each injection flow path 24, the cross-sectional area of the throttle flow path 92 is equal to or larger than the cross-sectional area of the minimum flow path of the nozzle 90.

Needless to say, when one nozzle 90 is referred to as the first nozzle 90, it can be explained that the N nozzles 90 include the first nozzle 90.

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 the gas-phase refrigerant dissipates heat to the outside air or the like via the heat dissipation circuit 14 to condense, and a liquid-phase refrigerant is generated. 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.

Liquid-phase refrigerant is supplied to the main flow path 21 and the bearing lubrication flow path 91 through the refrigerant supply path 11.

The liquid-phase refrigerant flowing in the main flow path 21 is pressurized by centrifugal force inside the injection flow path 24 and atomized through a nozzle 90 provided at the tip of the injection flow path 24. The atomized liquid phase refrigerant flows out toward the refrigerant flow path 40 inside the compressor 3.

The liquid-phase refrigerant flowing in the bearing lubrication flow path 91 lubricates the slide bearing 18 so that the slide bearing 18 does not seize. Even if the nozzle screw 90a is loosened or damaged, the amount of liquid-phase refrigerant flowing out to the refrigerant flow path 40 by providing the throttle flow path 92 having a narrower cross-sectional area than the flow paths before and after the nozzle screw 90a. Is restricted. Therefore, the liquid phase refrigerant can be continuously supplied to the slide bearing 18 as lubricating water, and it is possible to prevent the slide bearing 18 from seizing due to insufficient or exhausted bearing lubricating water.

FIG. 5 is a flowchart showing an operation method of the speed type compressor 3 including the rotating body 27 and the slide bearing 18 that rotatably supports the rotating body 27.

In step S1, the vapor phase refrigerant is supplied to the compression process of the compressor 3. Hereinafter, this supply may be referred to as a first supply.

In step S2, the liquid phase refrigerant is supplied to the slide bearing 18. Hereinafter, this supply may be referred to as a second supply.

In step S3, the liquid phase refrigerant flows into the rotating body 27. In step S4, the flow rate of the liquid phase refrigerant flowing into the rotating body 27 is reduced. In step S5, the liquid-phase refrigerant having a reduced flow rate is supplied to the gas-phase refrigerant in the compression process via the nozzle 90. Steps S3, S4 and S5 are executed in this order. Hereinafter, the combination of steps S3, S4 and S5 may be referred to as a third supply. The third supply is the supply of the liquid phase refrigerant to the gas phase refrigerant in the compression process.

As shown in FIG. 5, the first supply, the second supply and the third supply 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, in the refrigeration cycle apparatus according to the present disclosure, the slide bearing is unlikely to seize. 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 Slide bearing 19 Discharge flow path 21 Main flow path 21a Inflow port 24 Injection flow path 25 rotation 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 Interwing flow path 40 Refrigerant flow path 41 Diffuser 42 Swirling chamber 90 Nozzle 90a Nozzle screw 91 Bearing lubrication flow path 92 Squeeze flow path 95 Cylinder body 100 Refrigeration cycle device 241 First part 242 Second part

Claims (7)

A rotating body including a rotating shaft and an impeller,
A refrigerant flow path located around the rotating body and through which a vapor phase refrigerant flows,
A plain bearing that rotatably supports the rotating body,
A bearing lubrication flow path located between the plain bearing and the rotating shaft and to which a liquid phase refrigerant is supplied,
A main flow path that communicates with the bearing lubrication flow path, extends in the axial direction of the rotating body inside the rotating body, and has an inflow port into which the liquid phase refrigerant is introduced.
A flow path that is located inside the rotating body, branches 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. The refrigerant flow path is provided with an injection flow path provided with a first nozzle for flowing out the liquid phase refrigerant.
A speed type compressor provided with a first throttle flow path through which the liquid phase refrigerant passes between the inflow port and the first nozzle. The first nozzle is provided in the injection flow path by screwing.
The speed type compressor according to claim 1. The number of nozzles for flowing out the liquid phase refrigerant flowing from the first throttle flow path to the refrigerant flow path is N.
The cross-sectional area of the first throttle flow path is equal to or larger than the specific cross-sectional area of the N nozzles.
The speed compressor according to claim 1 or 2.
Here, the N nozzles include the first nozzle. N is a natural number of 1 or more. When N = 1, the specific cross-sectional area is the cross-sectional area of the minimum flow path of the first nozzle. When N ≧ 2, the specific cross-sectional area is the sum of the cross-sectional areas of the minimum flow paths of the N nozzles. The throttle flow path is provided in the main flow path.
The speed compressor according to any one of claims 1 to 3. The first nozzle sprays the liquid phase refrigerant into the refrigerant flow path.
The speed compressor according to any one of claims 1 to 4. Evaporator and
The speed compressor according to any one of claims 1 to 5.
Condenser and
Equipped with a refrigeration cycle device. A method of operating a speed compressor including a rotating body and a slide bearing that rotatably supports the rotating body.
Performing the first supply to supply the gas phase refrigerant to the compression process,
Performing a second supply to supply the liquid phase refrigerant to the slide bearing, and
A third supply of the liquid phase refrigerant to the gas phase refrigerant in the compression process is included.
The third supply is
Inflowing the liquid phase refrigerant into the rotating body and
By reducing the flow rate of the liquid phase refrigerant that has flowed into the rotating body,
An operation method comprising supplying the liquid phase refrigerant having a reduced flow rate to the gas phase refrigerant in the compression process via a first nozzle.

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