CN114846283A

CN114846283A - Refrigeration cycle device

Info

Publication number: CN114846283A
Application number: CN202080089318.5A
Authority: CN
Inventors: 森下卓美; 沟畑隼平
Original assignee: Mitsubishi Electric Corp
Current assignee: Mitsubishi Electric Corp
Priority date: 2020-01-07
Filing date: 2020-01-07
Publication date: 2022-08-02
Anticipated expiration: 2040-01-07
Also published as: CN114846283B; JP7292428B2; WO2021140566A1; JPWO2021140566A1

Abstract

An object of the present disclosure is to provide a refrigeration cycle device capable of controlling the amount of oil injected into a compression chamber. The refrigeration cycle device is provided with: a main circuit in which a scroll compressor, an oil separator, a first heat exchanger, a pressure reducing device, and a second heat exchanger are connected in sequence by piping, and in which a refrigerant circulates; an oil injection circuit branched from the oil separator and connected to an injection pipe of the scroll compressor; and a control device for controlling the operation of the refrigeration cycle device. The oil injection circuit is provided with a first control valve that adjusts the flow rate of oil flowing in the oil injection circuit by being controlled by a control device.

Description

Refrigeration cycle device

Technical Field

The present disclosure relates to a refrigeration cycle apparatus including a refrigerant circuit having an oil injection circuit.

Background

As a refrigeration cycle apparatus, a configuration is known which includes a scroll compressor having an injection flow path for supplying oil to a compression chamber in the middle of compression. For example, the oil-filled hermetic scroll compressor disclosed in patent document 1 is configured such that a part of oil separated by an oil separator provided on the discharge side of the scroll compressor is supplied from an injection port to a compression chamber via an oil supply delivery pipe and an injection pipe. The compression chamber is formed by combining a fixed wrap of the fixed scroll and an orbiting wrap of the orbiting scroll so as to mesh with each other.

Patent document 1: japanese laid-open patent publication No. 5-5486

However, the oil-filled hermetic scroll compressor disclosed in patent document 1 is not configured to control the amount of oil injected into the compression chamber, and therefore oil is always injected into the compression chamber. Therefore, in the scroll compressor operated by the inverter control, as the operation frequency becomes higher, the amount of oil introduced into the compression chamber increases, and there are concerns about damage to the scroll by oil compression and performance degradation due to an increase in the circulation amount of discharged oil.

Disclosure of Invention

The present disclosure has been made to solve the above problems, and an object thereof is to provide a refrigeration cycle device capable of controlling the amount of oil injected into a compression chamber.

The refrigeration cycle device according to the present disclosure includes: a main circuit in which a scroll compressor having a compression chamber for compressing a refrigerant and an injection pipe connected to the compression chamber, an oil separator, a first heat exchanger, a pressure reducing device, and a second heat exchanger are connected in order by pipes, and in which the refrigerant circulates; an oil injection circuit branched from the oil separator and connected to the injection pipe of the scroll compressor; and a control device for controlling the operation of the refrigeration cycle device, wherein the oil injection circuit is provided with a first control valve which is controlled by the control device to adjust the flow rate of the oil flowing in the oil injection circuit.

According to the refrigeration cycle apparatus of the present disclosure, since the first control valve that adjusts the flow rate of the oil is provided in the oil injection circuit, the flow rate and timing of the oil injected into the compression chamber can be controlled. Therefore, since the amount of oil supplied to the compression chamber can be adjusted in a state where the operating frequency of the scroll compressor is in the high speed region, damage to the wrap due to oil compression can be suppressed, and performance degradation due to an increase in the circulation amount of discharged oil can be suppressed.

Drawings

Fig. 1 is a refrigerant circuit diagram of a refrigeration cycle apparatus according to embodiment 1.

Fig. 2 is a schematic longitudinal sectional view showing a scroll compressor which is a component of the refrigeration cycle apparatus according to embodiment 1.

Fig. 3 is a refrigerant circuit diagram of the refrigeration cycle apparatus according to embodiment 2.

Fig. 4 is a refrigerant circuit diagram of the refrigeration cycle apparatus according to embodiment 3.

Fig. 5 is a refrigerant circuit diagram of the refrigeration cycle apparatus according to embodiment 4.

Fig. 6 is a refrigerant circuit diagram of the refrigeration cycle apparatus according to embodiment 5.

Detailed Description

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and the description thereof will be omitted or simplified as appropriate. The shape, size, arrangement, and the like of the structure described in each drawing can be appropriately changed.

Embodiment mode 1

Fig. 1 is a refrigerant circuit diagram of a refrigeration cycle apparatus according to embodiment 1. Fig. 2 is a schematic vertical cross-sectional view illustrating a scroll compressor which is a component of the refrigeration cycle apparatus according to embodiment 1. The refrigeration cycle apparatus according to embodiment 1 is used for applications such as an air conditioner, a refrigeration apparatus, a refrigerator, a freezer, a vending machine, and a hot water supply apparatus. As shown in fig. 1, the refrigeration cycle apparatus includes a refrigerant circuit 100, and the refrigerant circuit 100 includes a main circuit a, a refrigerant injection circuit B, and an oil injection circuit C.

As shown in fig. 1 and 2, the main circuit a is configured by connecting a scroll compressor 200 having a compression chamber 30 for compressing a refrigerant and an injection pipe 12 connected to the compression chamber 30, an oil separator 201, a first heat exchanger 202, a pressure reducing device 203, and a second heat exchanger 204 in this order via pipes, and is configured to circulate the refrigerant.

As shown in fig. 1 and 2, the refrigerant injection circuit B is branched from a pipe between the first heat exchanger 202 and the pressure reducer 203 and is connected to the injection pipe 12 of the scroll compressor 200. The refrigerant injection circuit B is provided with a second control valve 207 that adjusts the flow rate of the refrigerant flowing through the refrigerant injection circuit B, and a second electromagnetic valve 208 that opens and closes the refrigerant injection circuit B. The second control valve 207 is constituted by, for example, an electronic expansion valve. In the refrigerant circuit 100, the second solenoid valve 208 may be omitted as long as the second control valve 207 can be adjusted in opening degree from 0% to 100%.

As shown in fig. 1 and 2, the oil injection circuit C is branched from the oil separator 201, connected to the second heat exchanger 204, connected to the refrigerant injection circuit B, and connected to the injection pipe 12 of the scroll compressor 200 via the refrigerant injection circuit B. The oil injection circuit C is provided with a first control valve 205 that adjusts the flow rate of oil flowing through the oil injection circuit C and a first solenoid valve 206 that opens and closes the oil injection circuit C between the connection points of the second heat exchanger 204 and the refrigerant injection circuit B. The first control valve 205 is constituted by, for example, an electronic expansion valve. In the refrigerant circuit 100, the first solenoid valve 206 may be omitted as long as the first control valve 205 is configured to be capable of adjusting the opening degree of 0% to 100%.

Next, each component constituting the refrigerant circuit 100 will be explained. First, the structure of the scroll compressor 200 will be described with reference to fig. 2.

The scroll compressor 200 is for sucking and compressing the refrigerant circulating through the refrigerant circuit 100, bringing the refrigerant into a high-temperature and high-pressure state, and discharging the refrigerant. As shown in fig. 2, the scroll compressor 200 includes: a housing 1 forming an outer contour; a main frame 2 fixed to an inner wall surface of the casing 1; a compression mechanism portion 3 having a compression chamber 30 for compressing a refrigerant; a drive mechanism 6 for driving the compression mechanism 3; and a main shaft 7 connecting the compression mechanism 3 and the drive mechanism 6.

The housing 1 is constituted by a pressure vessel. A suction pipe 10 for introducing the refrigerant from the outside into the casing 1 and a discharge pipe 11 for discharging the compressed refrigerant from the casing 1 to the outside are connected to the casing 1. The pressure of the refrigerant sucked from the suction pipe 10 is a low pressure Ps. The pressure of the refrigerant discharged from the discharge pipe 11 is high pressure Pd. An oil reservoir 14 for storing refrigerating machine oil is provided at the inner bottom of the casing 1. The refrigerating machine oil is supplied to the compression mechanism section 3, the bearings, and the like through an oil supply passage 70 formed in the main shaft 7.

The compression mechanism 3 includes a fixed scroll 4 and an oscillating scroll 5. The fixed scroll 4 is fixed to a main frame 2 by bolts or the like, and the main frame 2 is fixed to an inner wall surface of the casing 1. The fixed scroll 4 has a fixed platen 40 and a fixed wrap 41 which is an involute curve-shaped projection provided on a lower surface of the fixed platen 40. The orbiting scroll 5 includes an orbiting platen 50 and an orbiting wrap 51 which is an involute curve-shaped protrusion provided on an upper surface of the orbiting platen 50.

The fixed scroll 4 and the orbiting scroll 5 are disposed in the housing 1 in a state of a symmetrical scroll shape in which the fixed wrap 41 and the orbiting wrap 51 mesh with each other in opposite phases with respect to the rotation center of the main shaft 7. In the compression mechanism 3, the fixed scroll 4 and the orbiting scroll 5 are combined so that the fixed wrap 41 and the orbiting wrap 51 mesh with each other, whereby the compression chamber 30 is formed between the fixed wrap 41 and the orbiting wrap 51. The volume of the compression chamber 30 decreases from the radially outer side to the radially inner side as the main shaft 7 rotates.

A discharge port 42 is formed in the center of the fixed platen 40, and the discharge port 42 discharges the refrigerant that has been compressed in the compression chamber 30 and has a high temperature and a high pressure. A back plate 15 is fixedly attached to the upper surface of the fixed scroll 4 by bolting or the like, and a discharge flow path 15a communicating with the discharge port 42 is formed in the back plate 15. The back plate 15 is screwed with a discharge valve 16 that opens and closes the discharge flow path 15a in accordance with the pressure of the refrigerant. The discharge valve 16 opens the discharge flow path 15a when the refrigerant in the compression chamber 30 communicating with the discharge port 42 reaches a predetermined pressure. The compressed high-temperature and high-pressure refrigerant is discharged from the discharge port 42 into the discharge space 13 above the fixed scroll 4, and is discharged to the outside of the casing 1 through the discharge pipe 11.

Further, an injection passage 43 communicating with the compression chamber 30 is formed in the fixed platen 40. The injection flow path 43 is formed at a position communicating with the compression chamber 30 at the initial stage or the middle stage of the compression stroke during one rotation of the main shaft 7. The pressure in the compression chamber 30 at this time becomes an intermediate pressure between the low pressure Ps and the high pressure Pd. Further, a communication channel 15b communicating with the injection channel 43 is formed in the back plate 15. The injection pipe 12 communicating with the communication flow path 15b from the outside of the housing 1 is fixed to the back plate 15 via a connection member 12a. That is, the injection passage 43 is connected to the injection pipe 12 via the communication passage 15b. The refrigerant and the oil are supplied from the injection pipe 12 to the compression chamber 30 through the communication passage 15b and the injection passage 43.

The orbiting scroll 5 performs an orbital motion with respect to the fixed scroll 4 without performing a rotational motion via an oldham coupling 8 for preventing a rotational motion. The surface of the oscillating platen 50 on the side where the oscillating wrap 51 is not formed functions as an oscillating scroll thrust bearing surface. A hollow cylindrical boss portion 52 is provided at the center of the orbiting scroll thrust bearing surface. An eccentric shaft portion 71 is rotatably connected to the boss portion 52, and the eccentric shaft portion 71 is provided at one end of the main shaft 7. The orbiting scroll 5 orbits on the thrust sliding surface of the main frame 2 by the rotation of the eccentric shaft 71 of the main shaft 7 inserted into the boss 52.

The drive mechanism 6 is provided below the main frame 2, and rotates the orbiting scroll 5 coupled to the fixed scroll 4 via the main shaft 7. The drive mechanism 6 includes an annular stator 60 fixed to an inner wall surface of the housing 1 by shrink fitting or the like, and a rotor 61 provided to be rotatable so as to face an inner surface of the stator 60. The stator 60 has a structure in which a winding is wound around a core formed by laminating a plurality of electromagnetic steel sheets with an insulating layer interposed therebetween, for example. The rotor 61 is configured to have a permanent magnet built in an iron core formed by laminating a plurality of electromagnetic steel plates, and has a through hole penetrating in a vertical direction at a center thereof. The main shaft 7 is fixed to the through hole of the rotor 61. The driving mechanism 6 is configured to rotate the rotor 61 by energizing the stator 60, and the main shaft 7 rotates in accordance with the rotation of the rotor 61, and transmits a driving force to the compression mechanism 3 coupled via the main shaft 7.

Next, each component of the refrigerant circuit 100 other than the scroll compressor 200 will be described. The oil separator 201 is connected to the discharge side of the scroll compressor 200, and separates oil contained in the refrigerant gas discharged from the scroll compressor 200. The oil separated from the refrigerant gas by the oil separator 201 is returned to the suction side of the scroll compressor 200 through the oil injection circuit C. The oil that has not been separated by the oil separator 201 flows through the first heat exchanger 202, the pressure reducing device 203, and the second heat exchanger 204 in this order, and returns to the suction side of the scroll compressor 200.

The first heat exchanger 202 in embodiment 1 functions as a condenser. The first heat exchanger 202 is for exchanging heat between the refrigerant discharged from the scroll compressor 200 and a heat medium such as air or water to condense and liquefy the refrigerant. The inflow side of the first heat exchanger 202 is connected to the oil separator 201, and the outflow side is connected to the pressure reducing device 203.

The decompression device 203 decompresses and expands the supplied refrigerant. The pressure reducing device 203 is constituted by, for example, an expansion valve or a capillary tube.

The second heat exchanger 204 in embodiment 1 functions as an evaporator. The second heat exchanger 204 exchanges heat between the air drawn from the air inlet and the refrigerant, and is configured to allow a low-pressure refrigerant liquid (or a gas-liquid two-phase refrigerant) to flow therein, exchange heat with the air, and evaporate the refrigerant. The second heat exchanger 204 is connected to the pressure reducing device 203 on the inflow side and to the scroll compressor 200 on the outflow side.

The control device 300 is used to control the entire refrigeration cycle device. The control device 300 controls the rotation speed of the scroll compressor 200, the opening degree of an expansion valve constituting the pressure reducing device 203, the first control valve 205 and the second control valve 207, and the opening and closing operations of the first solenoid valve 206 and the second solenoid valve 208, for example. The control device 300 is constituted by a microcomputer or the like, and includes a CPU, a RAM, a ROM, and the like.

Next, the flow and injection operation of the refrigerant in the refrigerant circuit 100 in embodiment 1 will be described. In the main circuit a, the refrigerant discharged from the scroll compressor 200 is separated into refrigerant and oil in the oil separator 201, and then cooled in the first heat exchanger 202. The refrigerant cooled in the first heat exchanger 202 is decompressed by the decompression device 203, and then heated in the second heat exchanger 204 to become a refrigerant gas. The refrigerant gas flowing out of the second heat exchanger 204 is returned to the scroll compressor 200.

Here, the controller 300 closes the first control valve 205 and the first solenoid valve 206 and opens the second control valve 207 and the second solenoid valve 208 during the refrigerant injection operation. As a result, the injection refrigerant, which is a part of the high-pressure liquid refrigerant cooled in the first heat exchanger 202, flows into the refrigerant injection circuit B, is depressurized by the second control valve 207 to be in a liquid state or a two-phase state, and flows into the injection pipe 12 of the scroll compressor 200 via the second electromagnetic valve 208. The injection refrigerant flowing into the injection pipe 12 flows into the compression chamber 30 during compression through the communication passage 15b and the injection passage 43. At this time, the first control valve 205 and the first electromagnetic valve 206 of the oil injection circuit C are closed, so that the oil does not flow into the injection pipe 12.

In addition, the control device 300 opens the first control valve 205 and the first solenoid valve 206 and closes the second control valve 207 and the second solenoid valve 208 during the oil injection operation. As a result, the oil discharged from the scroll compressor 200 and separated into the refrigerant and a part of the oil in the oil by the oil separator 201 flows into the oil injection circuit C, becomes high-pressure oil cooled by the second heat exchanger 204, is decompressed and flow-rate-adjusted by the second control valve 207, is connected to the pipe of the refrigerant injection circuit B, and flows into the injection pipe 12 of the scroll compressor 200. The injection oil flowing into the injection pipe 12 flows into the compression chamber 30 during compression through the communication passage 15b and the injection passage 43. At this time, the second control valve 207 and the second electromagnetic valve 208 of the refrigerant injection circuit B are closed, so that the refrigerant does not flow into the injection pipe 12.

The internal pressure P of the compression chamber 30 when the injection flow path 43 communicates with the compression chamber 30 during compression is lower than the internal pressure Pm in the refrigerant injection circuit B and the oil injection circuit C. This is because, as described above, the injection flow path 43 is formed at a position communicating with the compression chamber 30 in the initial or middle stage of the compression stroke during one rotation of the main shaft 7. Then, the injection refrigerant or the injection oil flows from the injection pipe 12 into the communication passage 15B and the injection passage 43 due to a differential pressure between the internal pressure P of the compression chamber 30 and the internal pressure Pm in the refrigerant injection circuit B and the oil injection circuit C, and is supplied to the compression chamber 30. Thereby, the gas refrigerant in the middle of compression is cooled. Oil is supplied into the compression chamber 30 to seal the space between the fixed wrap 41 and the orbiting wrap 51.

As described above, the refrigeration cycle device according to embodiment 1 includes: a main circuit a in which a scroll compressor 200 having a compression chamber 30 for compressing a refrigerant and an injection pipe 12 connected to the compression chamber 30, an oil separator 201, a first heat exchanger 202, a pressure reducing device 203, and a second heat exchanger 204 are connected in order by pipes, and in which the refrigerant circulates; an oil injection circuit C branched from the oil separator 201 and connected to the injection pipe 12 of the scroll compressor 200; and a control device 300 that controls the operation of the refrigeration cycle device. The oil injection circuit C is provided with a first control valve 205, and the first control valve 205 is controlled by the control device 300 to adjust the flow rate of the oil flowing through the oil injection circuit C.

Therefore, in the refrigeration cycle apparatus according to embodiment 1, the first control valve 205 that adjusts the flow rate of the oil is provided in the oil injection circuit C, and therefore the flow rate and timing of the oil injected into the compression chamber 30 can be controlled. Therefore, since the amount of oil supplied to the compression chamber 30 can be adjusted in a state where the operating frequency of the scroll compressor 200 is in the high speed region, damage to the fixed wrap 41 and the orbiting wrap 51 due to oil compression can be suppressed, and performance degradation due to an increase in the circulation amount of the discharged oil can be suppressed.

The oil injection circuit C branches from the oil separator 201 and is connected to the injection pipe 12 of the scroll compressor 200 via the second heat exchanger 204. Therefore, in the refrigeration cycle apparatus according to embodiment 1, since the oil separated in the oil separator 201 can be cooled by the second heat exchanger 204 and then injected into the compression chamber 30, the refrigerant gas in the compression chamber 30 can be cooled, and the discharge temperature can be suppressed. Further, since oil having high viscosity can be injected into the compression chamber 30 by cooling the oil, the sealing property between the tooth tips of the fixed wrap 41 and the orbiting wrap 51 is improved, and the leakage loss of the refrigerant can be reduced, thereby improving the performance.

The refrigeration cycle apparatus according to embodiment 1 further includes a refrigerant injection circuit B that branches off from the pipe between the first heat exchanger 202 and the decompression device 203 and is connected to the injection pipe 12 of the scroll compressor 200. The refrigerant injection circuit B is provided with a second control valve 207, and the second control valve 207 is controlled by the control device 300 to control the flow rate of the refrigerant flowing through the refrigerant injection circuit B. Therefore, the refrigeration cycle apparatus according to embodiment 1 can adjust the flow rate and timing of the refrigerant injected into the compression chamber 30, and therefore, an appropriate amount of refrigerant can be injected into the compression chamber 30, and the operation range of the scroll compressor 200 and the frequency range to be used can be expanded.

Further, the control device 300 performs control for closing the first control valve 205 and opening the second control valve 207 during the refrigerant injection operation, and performs control for opening the first control valve 205 and closing the second control valve 207 during the oil injection operation. Therefore, the refrigeration cycle apparatus according to embodiment 1 can suppress the amount of circulation of the discharged oil and improve the performance by closing the oil injection circuit C during high-speed operation of the compressor, and can supply the oil between the fixed wrap 41 and the orbiting wrap 51 by injecting the oil during low-speed operation, thereby preventing wear of the fixed wrap 41 and the orbiting wrap 51 and improving the reliability.

Embodiment mode 2

Next, a refrigeration cycle apparatus according to embodiment 2 will be described with reference to fig. 3. Fig. 3 is a refrigerant circuit diagram of the refrigeration cycle apparatus according to embodiment 2. The same components as those of the refrigeration cycle apparatus described in embodiment 1 are denoted by the same reference numerals, and the description thereof is appropriately omitted.

As shown in fig. 3, the refrigeration cycle apparatus according to embodiment 2 includes a refrigerant circuit 101, and the refrigerant circuit 101 includes a main circuit a, a refrigerant injection circuit B, and an oil injection circuit C.

The main circuit a is configured by connecting the scroll compressor 200, the oil separator 201, the first heat exchanger 202, the pressure reducing device 203, and the second heat exchanger 204 in this order by pipes, and circulates a refrigerant. The first heat exchanger 202 in embodiment 2 functions as a condenser. The second heat exchanger 204 in embodiment 2 functions as an evaporator.

The refrigerant injection circuit B is branched from a pipe between the first heat exchanger 202 and the pressure reducing device 203 and connected to the injection pipe 12 of the scroll compressor 200. A second control valve 207 is provided in the refrigerant injection circuit B, and the second control valve 207 adjusts the flow rate of the oil flowing in the oil injection circuit C. The second control valve 207 is configured to be capable of adjusting the opening degree of 0% to 100%. As shown in embodiment 1, the refrigerant injection circuit B may be provided with a second electromagnetic valve 208 for opening and closing the refrigerant injection circuit B.

The oil injection circuit C is branched from the oil separator 201, connected to a portion between the second control valve 207 and the scroll compressor 200 in the refrigerant injection circuit B, and connected to the injection pipe 12 of the scroll compressor 200 via the refrigerant injection circuit B. The oil injection circuit C is provided with a first control valve 205, and the first control valve 205 adjusts the flow rate of oil flowing in the oil injection circuit C. The first control valve 205 is configured to be capable of adjusting the opening degree of 0% to 100%. As shown in embodiment 1, the oil injection circuit C may be provided with a first electromagnetic valve 206 for opening and closing the oil injection circuit C.

As described above, in the refrigeration cycle apparatus according to embodiment 2, the first control valve 205 that adjusts the flow rate of the oil is provided in the oil injection circuit C, and therefore the flow rate and timing of the oil injected into the compression chamber 30 can be controlled. Therefore, since the amount of oil supplied to the compression chamber 30 can be adjusted in a state where the operating frequency of the scroll compressor 200 is in the high speed region, damage to the fixed wrap 41 and the orbiting wrap 51 due to oil compression can be suppressed, and performance degradation due to an increase in the circulation amount of the discharged oil can be suppressed.

In addition, since the refrigeration cycle apparatus according to embodiment 2 can adjust the flow rate and timing of the refrigerant injected into the compression chamber 30, an appropriate amount of refrigerant can be injected into the compression chamber 30, and the operation range of the scroll compressor 200 and the frequency range to be used can be expanded.

In the refrigeration cycle apparatus according to embodiment 2, the oil injection circuit C is closed during high-speed operation of the compressor, so that the amount of oil that is discharged is suppressed to improve the performance, and oil is injected during low-speed operation to supply oil between the fixed wrap 41 and the orbiting wrap 51, thereby preventing wear of the fixed wrap 41 and the orbiting wrap 51 and improving the reliability.

Embodiment 3

Next, a refrigeration cycle apparatus according to embodiment 3 will be described with reference to fig. 4. Fig. 4 is a refrigerant circuit diagram of the refrigeration cycle apparatus according to embodiment 3. Note that the same components as those of the refrigeration cycle apparatuses described in embodiments 1 and 2 are denoted by the same reference numerals, and the description thereof is appropriately omitted.

The refrigerant circuit 102 of the refrigeration cycle apparatus according to embodiment 3 is characterized in that, in addition to the configuration of embodiment 2, a configuration is provided in which an oil return pipe 209 that bypasses the oil separator 201 and the suction side of the scroll compressor 200 is provided. The oil return pipe 209 is provided with a third control valve 210, and the flow rate of the oil flowing through the oil return pipe 209 is adjusted by controlling the third control valve 210 by the control device 300. The third control valve 210 is formed of an electronic expansion valve or the like capable of adjusting the opening degree of 0% to 100%. The oil return pipe 209 may be provided with an electromagnetic valve for opening and closing the oil return pipe 209.

The scroll compressor 200 has a sufficient amount of oil supplied to the compression mechanism 3 during high-speed operation. Therefore, the amount of oil supplied to the injection flow path 43 is zero or extremely small. However, if the high-speed operation of the scroll compressor 200 continues, oil may accumulate inside the oil separator 201 and the oil in the scroll compressor 200 may run out. Therefore, as in the refrigeration cycle apparatus according to embodiment 3, an oil return pipe 209 bypassing the oil separator 201 and the suction side of the scroll compressor 200 may be provided. Further, the oil return pipe 209 may be provided with a third control valve 210 to return oil to the suction side of the scroll compressor 200 in accordance with the oil amount in the oil separator 201. The amount of oil in the oil separator 201 is determined from the measured value of the amount of oil in the oil gauge. The amount of oil in the oil separator 201 may be determined from the operating frequency of the scroll compressor 200 and the operating time thereof. The oil amount in the oil separator 201 may be determined from an estimated value calculated from the oil amount returned to the scroll compressor 200 by the return oil pipe 209.

Embodiment 4

Next, a refrigeration cycle apparatus according to embodiment 4 will be described with reference to fig. 5. Fig. 5 is a refrigerant circuit diagram of the refrigeration cycle apparatus according to embodiment 4. Note that the same components as those of the refrigeration cycle devices described in embodiments 1 to 3 are denoted by the same reference numerals, and the description thereof is appropriately omitted.

The refrigeration cycle apparatus according to embodiment 4 is, for example, an air conditioner capable of cooling and heating. As shown in fig. 5, the refrigeration cycle apparatus includes a refrigerant circuit 103, and the refrigerant circuit 103 includes a main circuit a, a refrigerant injection circuit B, and an oil injection circuit C.

The main circuit a is configured by connecting the scroll compressor 200, the oil separator 201, the flow path switching unit 211, the first heat exchanger 202, the first pressure reducing device 212, the second pressure reducing device 213, and the second heat exchanger 204 in this order by pipes, and circulates a refrigerant.

The flow path switching unit 211 is, for example, a four-way valve, and has a function of switching the flow path of the refrigerant under the control of the control device 300. During the cooling operation, the flow path switching unit 211 switches the refrigerant flow path so as to connect the discharge side of the scroll compressor 200 to the first heat exchanger 202 and to connect the suction side of the scroll compressor 200 to the second heat exchanger 204, as indicated by the solid line in fig. 5. During the heating operation, the flow path switching unit 211 switches the refrigerant flow path so as to connect the discharge side of the scroll compressor 200 to the second heat exchanger 204 and to connect the suction side of the scroll compressor 200 to the first heat exchanger 202, as indicated by the broken line in fig. 5. The flow path switching means 211 may be configured by combining a two-way valve and a three-way valve.

The first heat exchanger 202 is configured to function as a condenser to liquefy the refrigerant during the cooling operation, and to function as an evaporator to vaporize the refrigerant during the heating operation. The second heat exchanger 204 functions as an evaporator during the cooling operation and functions as a condenser during the heating operation.

The first pressure reducer 212 and the second pressure reducer 213 are controlled by the control device 300, and reduce the pressure of the supplied refrigerant to expand the refrigerant. The first pressure reducer 212 and the second pressure reducer 213 are configured by, for example, expansion valves or capillary tubes.

The refrigerant injection circuit B is branched from a pipe between the first pressure reducer 212 and the second pressure reducer 213 and connected to the injection pipe 12 of the scroll compressor 200. A second control valve 207 is provided in the refrigerant injection circuit B, and the second control valve 207 adjusts the flow rate of the refrigerant flowing in the refrigerant injection circuit B. The second control valve 207 is configured to be capable of adjusting the opening degree of 0% to 100%. As shown in embodiment 1, the second electromagnetic valve 208 for opening and closing the refrigerant injection circuit B may be provided in the refrigerant injection circuit B.

The refrigerant circuit 103 in embodiment 4 is provided with an oil return pipe 209 that bypasses the oil separator 201 and the suction side of the scroll compressor 200. The oil return pipe 209 is provided with a third control valve 21, and the flow rate of oil flowing through the oil return pipe 209 is adjusted by controlling the third control valve 21 by the control device 300. The third control valve 210 is formed of an electronic expansion valve or the like capable of adjusting the opening degree of 0% to 100%. Although not shown, the oil return pipe 209 may be provided with an electromagnetic valve for opening and closing the oil return pipe 209.

As described above, the refrigeration cycle apparatus according to embodiment 4 can also obtain the same operational effects as those described in

embodiments

2 and 3.

Embodiment 5

Next, a refrigeration cycle apparatus according to embodiment 5 will be described with reference to fig. 6. Fig. 6 is a refrigerant circuit diagram of the refrigeration cycle apparatus according to embodiment 5. The same components as those of the refrigeration cycle devices described in embodiments 1 to 4 are denoted by the same reference numerals, and the description thereof is appropriately omitted.

As shown in fig. 6, the refrigeration cycle apparatus according to embodiment 5 differs from the refrigeration cycle apparatus according to embodiment 4 in the configuration of the oil injection circuit C. Therefore, in embodiment 5, only the configuration of the oil injection circuit C will be described, and the configuration of embodiment 4 will be applied to the other configurations.

The oil injection circuit C in embodiment 5 includes a first oil injection circuit C1 and a second oil injection circuit C2.

As shown in fig. 6, the first oil injection circuit C1 is branched from the oil separator 201, connected to the first heat exchanger 202, connected to the refrigerant injection circuit B, and connected to the injection pipe 12 of the scroll compressor 200 shown in fig. 2 via the refrigerant injection circuit B. A first control valve 205 is provided between the oil separator 201 and the first heat exchanger 202 in the first oil injection circuit C1, and the first control valve 205 is controlled by the control device 300 to adjust the flow rate of the oil flowing through the first oil injection circuit C1. The first control valve 205 is constituted by an electronic expansion valve or the like capable of adjusting the opening degree of 0% to 100%. Further, the first oil injection circuit C1 may be provided with an electromagnetic valve that opens and closes the first oil injection circuit C1.

As shown in fig. 6, the second oil injection circuit C2 is branched from the oil separator 201, connected to the second heat exchanger 204, connected to the refrigerant injection circuit B, and connected to the injection pipe 12 of the scroll compressor 200 shown in fig. 2 via the refrigerant injection circuit B. A first control valve 205 is provided between the oil separator 201 and the second heat exchanger 204 in the second oil injection circuit C2, and the first control valve 205 is controlled by the control device 300 to adjust the flow rate of the oil flowing through the second oil injection circuit C2. The first control valve 205 is constituted by an electronic expansion valve or the like capable of adjusting the opening degree of 0% to 100%. Further, the second oil injection circuit C2 may be provided with an electromagnetic valve for opening and closing the second oil injection circuit C2.

In the refrigerant circuit 104 of embodiment 5, when the first heat exchanger 202 functions as an evaporator, oil is supplied from the injection pipe 12 to the compression chamber 30 through the first oil injection circuit C1, and when the second heat exchanger 204 functions as an evaporator, oil is supplied from the injection pipe 12 to the compression chamber 30 through the second oil injection circuit C2.

As described above, the refrigeration cycle apparatus according to embodiment 5 can also obtain the same operational effects as those described in embodiment 1.

The refrigeration cycle apparatus has been described above based on the embodiments, but the refrigeration cycle apparatus is not limited to the configuration of the above-described embodiments. The refrigeration cycle apparatus is not limited to the above-described components, and may include other components or omit some of the components. For example, the refrigerant injection circuit B is not necessarily provided, and may be omitted. The oil separator 201 may be provided between the condenser and the pressure reducing device, or between the pressure reducing device and the branch point of the refrigerant injection circuit B. In this case, the temperature of the oil can be lowered in accordance with the lowering of the temperature of the refrigerant by the refrigeration cycle. The pressure level is not particularly determined by a relation with an absolute value, but is relatively determined in a state, an operation, and the like in a system, a device, and the like. In short, the refrigeration cycle apparatus includes a range of design changes and application changes that are generally performed by those skilled in the art, without departing from the technical spirit thereof.

Description of the reference numerals

A housing; a main frame; a compression mechanism portion; a fixed scroll; an oscillating scroll; a drive mechanism portion; a spindle; an oldham coupling; a suction tube; an exhaust pipe; injecting tubing; a connecting member; discharging the space; an oil reservoir; a back plate; a discharge flow path; communicating the flow path; a discharge valve; a compression chamber; fixing the bedplate; a fixed scroll wrap; a discharge port; injecting a flow path; oscillating the platen; oscillating the wrap; a boss portion; a stator; 61.. rotor; an oil supply flow path; 71.. an eccentric shaft portion; 100. 101, 102, 103.. refrigerant circuit; a scroll compressor; an oil separator; a first heat exchanger; a pressure reduction device; a second heat exchanger; a first control valve; a first solenoid valve; a second control valve; a second solenoid valve; an oil return pipe; a third control valve; a flow path switching unit; a first pressure relief device; a second pressure relief device; a control device; a main circuit; a refrigerant injection circuit; injecting oil into the loop; c1.. a first oil injection circuit; the second oil is injected into the circuit.

Claims

1. A refrigeration cycle apparatus, wherein,

the refrigeration cycle device is provided with:

a main circuit in which a scroll compressor having a compression chamber for compressing a refrigerant and an injection pipe connected to the compression chamber, an oil separator, a first heat exchanger, a pressure reducing device, and a second heat exchanger are connected in order by pipes, and in which the refrigerant circulates;

an oil injection circuit branched from the oil separator and connected to the injection pipe of the scroll compressor; and

a control device for controlling the operation of the refrigeration cycle device,

the oil injection circuit is provided with a first control valve that is controlled by the control device to adjust the flow rate of oil flowing in the oil injection circuit.

2. The refrigeration cycle apparatus according to claim 1,

the oil injection circuit branches from the oil separator and is connected to the injection pipe of the scroll compressor via the second heat exchanger.

3. The refrigeration cycle device according to claim 1 or 2, wherein,

the refrigeration cycle apparatus further includes a refrigerant injection circuit that branches from a pipe between the first heat exchanger and the decompression device and is connected to the injection pipe of the scroll compressor,

the refrigerant injection circuit is provided with a second control valve that is controlled by the control device to adjust the flow rate of the refrigerant flowing through the refrigerant injection circuit.

4. The refrigeration cycle apparatus according to claim 3, wherein,

the control device performs control to close the first control valve and open the second control valve during a refrigerant injection operation, and performs control to open the first control valve and close the second control valve during an oil injection operation.

5. The refrigeration cycle device according to any one of claims 1 to 4, wherein,

the refrigeration cycle device further includes an oil return pipe connecting the oil separator and the discharge side of the scroll compressor,

the oil return pipe is provided with a third control valve that is controlled by the control device to adjust the flow rate of the oil flowing through the oil return pipe.