CN114846283B

CN114846283B - Refrigeration cycle device

Info

Publication number: CN114846283B
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: 2024-01-16
Anticipated expiration: 2040-01-07
Also published as: JP7292428B2; JPWO2021140566A1; WO2021140566A1; CN114846283A

Abstract

The present disclosure provides a refrigeration cycle device capable of controlling an amount of oil injected into a compression chamber. A 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 this order by piping, and in which a refrigerant is circulated; 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 controlled by a control device to adjust the flow rate of the oil flowing in the oil injection circuit.

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 device, a configuration is known that 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 injection type hermetic scroll compressor disclosed in patent document 1 is configured such that a part of oil separated by an oil separator provided on a discharge side of the scroll compressor is supplied from an injection port to a compression chamber via an oil supply pipe and an injection pipe. The compression chamber is formed by combining a fixed scroll wrap of the fixed scroll and a swing scroll wrap of the swing scroll in a meshing manner.

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

However, the oil injection type hermetic scroll compressor disclosed in patent document 1 is not configured to control the amount of oil injected into the compression chamber, and thus oil is always injected into the compression chamber. Therefore, in a scroll compressor that is operated by inverter control, as the operating frequency becomes higher, the amount of oil introduced into the compression chamber increases, and there are concerns about damage to the scroll wraps caused by oil compression and a concern about performance degradation caused by an increase in the circulation amount of discharged oil.

Disclosure of Invention

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

The refrigeration cycle device according to the present disclosure includes: a main circuit including 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 connected in this order by pipes, and configured to circulate the refrigerant; 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 a first control valve is provided in the oil injection circuit, and the first control valve 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 for adjusting 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, in a state where the operating frequency of the scroll compressor is in the high-speed region, the amount of oil supplied to the compression chamber can be adjusted, and therefore, damage to the scroll wraps caused by oil compression can be suppressed, and degradation in performance caused by an increase in the circulation amount of discharged oil can be suppressed.

Drawings

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

Fig. 2 is a schematic vertical sectional view showing a scroll compressor which is a constituent element 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

Embodiments of the present disclosure will be described below with reference to the accompanying drawings. In the drawings, the same or corresponding portions are denoted by the same reference numerals, and description thereof is omitted or simplified as appropriate. The configuration described in each drawing may be changed in shape, size, arrangement, and the like as appropriate.

Embodiment 1

Fig. 1 is a refrigerant circuit diagram of the refrigeration cycle apparatus according to embodiment 1. Fig. 2 is a schematic vertical sectional view showing a scroll compressor which is a constituent element 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 refrigerating 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 through 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 reducing 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 that adjusts the flow rate of the refrigerant flowing through the refrigerant injection circuit B, and a second solenoid 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 or the like. In the refrigerant circuit 100, the second electromagnetic valve 208 may be omitted as long as the second control valve 207 is configured to be capable of adjusting the opening degree by 0% to 100%.

As shown in fig. 1 and 2, the oil injection circuit C is branched from the oil separator 201, is connected to the second heat exchanger 204, is connected to the refrigerant injection circuit B, and is 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 for adjusting the flow rate of the oil flowing through the oil injection circuit C and a first solenoid valve 206 for opening and closing 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 or the like. 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 by 0% to 100%.

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

The scroll compressor 200 sucks and compresses the refrigerant circulating in the refrigerant circuit 100, and discharges the refrigerant in a high-temperature and high-pressure state. 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 housing 1; a compression mechanism part 3 having a compression chamber 30 for compressing a refrigerant; a driving 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 a 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. In addition, 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 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 a orbiting scroll 5. The fixed scroll 4 is fixed to the main frame 2 by bolts or the like, and the main frame 2 is fixed to the inner wall surface of the housing 1. The fixed scroll 4 includes a fixed base plate 40 and fixed scroll teeth 41, which are involute curve-shaped projections provided on the lower surface of the fixed base plate 40. The orbiting scroll 5 has an orbiting platen 50 and an orbiting scroll wrap 51, which is an involute curve-shaped protrusion provided on the upper surface of the orbiting platen 50.

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

A discharge port 42 is formed in the center of the stationary platen 40, and the discharge port 42 discharges the refrigerant compressed in the compression chamber 30 to a high temperature and high pressure. A back plate 15 is fixedly provided on the upper surface of the fixed scroll 4 by bolting or the like, and a discharge passage 15a communicating with the discharge port 42 is formed in the back plate 15. The back plate 15 is provided with a discharge valve 16 that opens and closes the discharge flow path 15a according to the pressure of the refrigerant, in a screw-fixed manner. When the refrigerant in the compression chamber 30 communicating with the discharge port 42 reaches a predetermined pressure, the discharge valve 16 opens the discharge flow path 15a. The compressed high-temperature and high-pressure refrigerant is discharged from the discharge port 42 to the discharge space 13 in the upper portion of the fixed scroll 4, and is discharged to the outside of the housing 1 through the discharge pipe 11.

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

The orbiting scroll 5 performs an orbital motion with respect to the fixed scroll 4 without performing an autorotation motion by an oldham coupling 8 for preventing an autorotation motion. The surface of the swing platen 50 on the side where the swing scroll teeth 51 are not formed functions as a swing scroll thrust bearing surface. A hollow cylindrical boss 52 is provided in 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 performs an orbital motion on a thrust sliding surface of the main frame 2 by rotation of an eccentric shaft portion 71 of the main shaft 7 inserted into the boss portion 52.

The driving mechanism 6 is provided below the main frame 2, and rotationally drives the orbiting scroll 5 coupled via the main shaft 7 with respect to the fixed scroll 4. The driving mechanism 6 includes an annular stator 60 fixed to the inner wall surface of the housing 1 by a press fit or the like, and a rotor 61 provided rotatably so as to face the inner side surface of the stator 60. The stator 60 is configured such that, for example, a winding is wound around a core formed by laminating a plurality of electromagnetic steel sheets via an insulating layer. The rotor 61 has a structure in which a permanent magnet is built in an iron core formed by stacking a plurality of electromagnetic steel plates, and has a through hole penetrating in the vertical direction in the center. A spindle 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 to transmit driving force to the compression mechanism 3 coupled via the main shaft 7.

Next, each constituent element 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 via the oil injection circuit C. The oil not 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 configured to exchange heat between the discharged refrigerant from the scroll compressor 200 and a heat medium such as air or water, thereby condensing and liquefying 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 pressure reducing device 203 is configured to reduce the pressure of the supplied refrigerant and expand the refrigerant. The pressure reducing device 203 is constituted by, for example, an expansion valve, a capillary tube, or the like.

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

The control device 300 is used to control the entire refrigeration cycle device. The control device 300 performs, for example, rotation speed control of the scroll compressor 200, opening degree control of an expansion valve constituting the pressure reducing device 203, control of the first control valve 205 and the second control valve 207, opening and closing operations of the first solenoid valve 206 and the second solenoid valve 208, and the like. 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 according to embodiment 1 will be described. In the main circuit a, the refrigerant discharged from the scroll compressor 200 is separated into a 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 depressurized in the depressurizing 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 control device 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 at the time of 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 in the second control valve 207 to be in a liquid or 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 in the middle of compression through the communication passage 15b and the injection passage 43. At this time, the first control valve 205 and the first solenoid valve 206 of the oil injection circuit C are closed, so that the oil does not flow into the injection pipe 12.

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 at the time of the oil injection operation. As a result, a part of the oil discharged from the scroll compressor 200 and separated into the refrigerant and 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 depressurized 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 solenoid 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 pressures Pm in the refrigerant injection circuit B and the oil injection circuit C. As described above, the injection flow path 43 is formed at a position that communicates with the compression chamber 30 in the early or middle stage of the compression stroke in one rotation of the main shaft 7. Then, the injection refrigerant or the injection oil flows from the injection pipe 12 into the communication flow path 15B and the injection flow path 43 due to the 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. Further, oil is supplied into the compression chamber 30, and oil is sealed between the fixed scroll wrap 41 and the orbiting scroll wrap 51.

As described above, the refrigeration cycle apparatus 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 this order by pipes, and in which the refrigerant is circulated; 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 for controlling the operation of the refrigeration cycle device. The first control valve 205 is provided in the oil injection circuit C, and the first control valve 205 is controlled by the control device 300 to adjust the flow rate of the oil flowing in the oil injection circuit C.

Therefore, in the refrigeration cycle apparatus according to embodiment 1, the first control valve 205 for adjusting the flow rate of the oil is provided in the oil injection circuit C, so that 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 scroll wrap 41 and the oscillating scroll wrap 51 due to oil compression can be suppressed, and degradation in performance due to an increase in the circulation amount of 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, 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, so that the refrigerant gas in the compression chamber 30 can be cooled, and the discharge temperature can be suppressed. Further, since oil having a high viscosity can be injected into the compression chamber 30 by cooling the oil, the sealing between the tips of the fixed scroll wrap 41 and the oscillating scroll wrap 51 is improved, and leakage loss of the refrigerant can be reduced, thereby improving performance.

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

The control device 300 performs control to close the first control valve 205 and open the second control valve 207 during the refrigerant injection operation, and performs control to open the first control valve 205 and close the second control valve 207 during the oil injection operation. Therefore, the refrigeration cycle apparatus according to embodiment 1 can achieve an improvement in performance by closing the oil injection circuit C during high-speed operation of the compressor, and can achieve an improvement in reliability by preventing wear of the fixed scroll wrap 41 and the orbiting scroll wrap 51 by supplying oil between the fixed scroll wrap 41 and the orbiting scroll wrap 51 by injecting oil during low-speed operation.

Embodiment 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 description thereof is omitted as appropriate.

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 a scroll compressor 200, an oil separator 201, a first heat exchanger 202, a pressure reducing device 203, and a second heat exchanger 204 in this order through pipes, and is configured to circulate a refrigerant. The first heat exchanger 202 in embodiment 2 functions as a condenser. In addition, 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 is 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 by 0% to 100%. As shown in embodiment 1, the refrigerant injection circuit B may be provided with a second solenoid valve 208 for opening and closing the refrigerant injection circuit B.

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

As described above, the refrigeration cycle apparatus according to embodiment 2 is provided with the first control valve 205 for adjusting the flow rate of the oil in the oil injection circuit C, and thus can control the flow rate and timing of the oil injected into the compression chamber 30. 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 scroll wrap 41 and the oscillating scroll wrap 51 due to oil compression can be suppressed, and degradation in performance due to an increase in the circulation amount of 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 to be injected into the compression chamber 30, an appropriate amount of refrigerant can be injected into the compression chamber 30, and the operating range of the scroll compressor 200 and the frequency range to be used can be widened.

In the refrigeration cycle apparatus according to embodiment 2, the oil injection circuit C is closed during high-speed operation of the compressor, whereby the circulation amount of discharged oil can be suppressed to improve the performance, and oil can be supplied between the fixed scroll wrap 41 and the orbiting scroll wrap 51 by injecting oil during low-speed operation, whereby wear of the fixed scroll wrap 41 and the orbiting scroll wrap 51 can be prevented to improve 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. The same components as those of the refrigeration cycle apparatus described in embodiments 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

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

The scroll compressor 200 supplies a sufficient amount of oil to the compression mechanism 3 during high-speed operation. Therefore, the amount of oil supplied to the injection flow path 43 is set to zero or very small. However, if the high-speed operation of the scroll compressor 200 is continued, there is a possibility that oil is stored in the oil separator 201 and the oil in the scroll compressor 200 is exhausted. Therefore, as in the refrigeration cycle apparatus according to embodiment 3, a return pipe 209 may be provided to bypass the oil separator 201 and the suction side of the scroll compressor 200. Further, a third control valve 210 may be provided in the return pipe 209 to return oil to the suction side of the scroll compressor 200 according to the oil amount of the oil separator 201. The oil amount in the oil separator 201 is obtained from the actual measurement value of the oil amount of the oil meter. The oil amount in the oil separator 201 may be obtained from the operating frequency of the scroll compressor 200 and the operating time thereof. The oil amount in the oil separator 201 may be obtained from an estimated value calculated from the oil amount returned to the scroll compressor 200 by the return 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 apparatus described in embodiments 1 to 3 are denoted by the same reference numerals, and description thereof is omitted as appropriate.

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 through pipes, and is configured to circulate the refrigerant.

The flow path switching means 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. At the time of 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 shown by the solid line in fig. 5. At the time of heating operation, as shown by the broken line in fig. 5, the flow path switching means 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 connect the suction side of the scroll compressor 200 to the first heat exchanger 202. The flow path switching means 211 may be constituted by combining a two-way valve or 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 gasify the refrigerant during the heating operation. The second heat exchanger 204 functions as an evaporator in the cooling operation and functions as a condenser in the heating operation.

The first decompressing device 212 and the second decompressing device 213 are controlled by the control device 300, and decompress and expand the supplied refrigerant. The first pressure reducing device 212 and the second pressure reducing device 213 are constituted by, for example, an expansion valve, a capillary tube, or the like.

The refrigerant injection circuit B is branched from a pipe between the first pressure reducing device 212 and the second pressure reducing device 213, and is 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 by 0% to 100%. As shown in embodiment 1, a second electromagnetic valve 208 may be provided in the refrigerant injection circuit B to open and close the refrigerant injection circuit B.

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

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

As described above, in the refrigeration cycle apparatus according to embodiment 4, the same operational effects as those described in embodiments 2 and 3 can be obtained.

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 apparatus described in embodiments 1 to 4 are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

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

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, is connected to the first heat exchanger 202, is connected to the refrigerant injection circuit B, and is 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 in 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 by 0% to 100%. Further, a solenoid valve for opening and closing the first oil injection circuit C1 may be provided in the first oil injection circuit C1.

As shown in fig. 6, the second oil injection circuit C2 is branched from the oil separator 201, is connected to the second heat exchanger 204, is connected to the refrigerant injection circuit B, and is 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 in 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 by 0% to 100%. Further, a solenoid valve for opening and closing the second oil injection circuit C2 may be provided in the second oil injection circuit C2.

In the refrigerant circuit 104 according to 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, in the refrigeration cycle apparatus according to embodiment 5, the same operational effects as those described in embodiment 1 can be obtained.

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 embodiments. The refrigeration cycle apparatus is not limited to the above-described components, and may include other components, or may 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 a branch point of the refrigerant injection circuit B. In this case, the temperature of the oil can also be reduced with a reduction in the temperature of the refrigerant caused by the refrigeration cycle. The pressure level is not particularly determined by the relation with the absolute value, but is relatively determined in the state, operation, and the like of the system, the 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; main frame; compression mechanism; fixed scroll; oscillating scroll; a drive mechanism section; main shaft; cross-head coupling; suction tube; discharge tube; injection tubing; a connecting part; discharge space; an oil reservoir; back plate; a discharge flow path; a communication flow path; discharge valve; compression chamber; 40. the platen is fixed; fixed scroll wraps; discharge port; injection flow path; swing the platen; 51. oscillating wraps; shaft sleeve; stator; 61. rotor; an oil supply flow path; 71. eccentric shaft portions; 100. 101, 102, 103; scroll compressor; oil separator; a first heat exchanger; pressure relief device; a second heat exchanger; first control valve; a first solenoid valve; a second control valve; a second solenoid valve; return tubing; third control valve; a flow path switching unit; first pressure relief device; a second pressure relief device; control means; a main circuit; a refrigerant injection circuit; oil injection circuit; 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 including 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 connected in this order by pipes, and configured to circulate the refrigerant;

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 has:

a first oil injection circuit branched from the oil separator and connected to the injection pipe of the scroll compressor via the first heat exchanger; and

a second oil injection circuit branched from the oil separator and connected to the injection pipe of the scroll compressor via the second heat exchanger,

the first oil injection circuit and the second oil injection circuit are each provided with a first control valve controlled by the control device to adjust the flow rate of the oil flowing in the oil injection circuit,

the control device performs control to close the first control valve at a high speed operation of the scroll compressor and to open the first control valve at a low speed operation of the scroll compressor, thereby performing oil injection.

2. The refrigeration cycle apparatus according to claim 1, wherein,

the refrigeration cycle device further includes a refrigerant injection circuit branched from a pipe between the first heat exchanger and the pressure reducing device and 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.

3. The refrigeration cycle apparatus according to claim 2, 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.

4. A refrigeration cycle apparatus according to any one of claim 1 to 3, wherein,

the refrigeration cycle device further includes a return pipe connecting the oil separator to a suction side of the scroll compressor,

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