JP4807071B2 - Refrigeration equipment - Google Patents

Description

  The present invention relates to a refrigeration apparatus including an oil separator for returning refrigeration oil contained in refrigerant discharged from a compressor to the compressor.

  Conventionally, a refrigeration apparatus having a refrigerant circuit for performing a vapor compression refrigeration cycle is known. This refrigeration apparatus is widely used, such as refrigerators for storing foods and the like, refrigerators such as freezers, and air conditioners for heating and cooling the room. In this refrigeration apparatus, the refrigerant discharged from the compressor in the refrigerant circuit circulates in the order of the condenser, the expansion mechanism, and the evaporator, thereby performing a vapor compression refrigeration cycle.

In this refrigerant circuit, the refrigerant discharged from the compressor contains refrigerating machine oil used for lubrication in the compressor. In order to prevent the oil from rising from the compressor, an oil separator is provided on the discharge side of the compressor, and the oil separator separates the refrigerating machine oil from the refrigerant discharged from the compressor and returns it to the compressor. However, it is disclosed in Patent Document 1, for example. In this refrigeration apparatus, the oil return passage from the oil separator is connected to a low-pressure gas pipe connected to the suction side of the compressor. The oil return passage is provided with an electromagnetic valve as an on-off valve. In this configuration, when the on-off valve is opened, the refrigeration oil separated from the refrigerant by the oil separator is returned to the suction side of the compressor through the oil return passage.
International Publication No. 03/083380 Pamphlet

  By the way, in the conventional refrigeration apparatus, when the refrigeration oil separated by the oil separator is returned to the compressor, the high-pressure refrigerant in the oil separator is also returned to the compressor together with the refrigeration oil, so that the operation capacity of the refrigeration apparatus is reduced. There's a problem. In other words, since the amount of low-pressure refrigerant sucked by the compressor is reduced by returning the high-pressure refrigerant in the oil separator to the suction side of the compressor, the circulation amount of refrigerant in the refrigerant circuit will not be reduced. Driving ability is reduced.

  Further, when a scroll compressor is used as the compressor, the refrigeration oil may not be sufficiently supplied to the high pressure side of the compression mechanism. Specifically, the scroll compressor is configured such that the refrigerating machine oil stored therein is sent to the outside of the scroll spiral, that is, to the low pressure side of the compression mechanism. Since the refrigeration oil returned from the oil separator is also returned to the low pressure side of the compression mechanism, it is difficult for the refrigeration oil to reach the high pressure side located at the center side of the scroll spiral. In particular, when the scroll compressor is applied to a refrigeration apparatus in a low temperature region, the refrigeration oil returned from the oil separator has a higher viscosity and lower fluidity, so that it is more difficult to spread to the high pressure side of the compression mechanism.

  The present invention has been made in view of the above points, and an object of the present invention is to provide a compression mechanism in a scroll compressor without reducing the operating capacity of the refrigerating apparatus in a refrigeration apparatus including a refrigerant circuit provided with a scroll compressor. It is to improve the lubrication.

A first invention includes a compressor (14) having a compression mechanism (82) constituted by a scroll fluid machine, an oil separator (33) for separating refrigeration oil from refrigerant discharged from the compressor (14), Assuming a refrigeration apparatus (1) comprising a refrigerant circuit (4) provided with an oil return passage (34) for returning the refrigeration oil separated by the oil separator (33) to the compressor (14). To do. In the refrigeration apparatus (1), the oil return passage (34) is connected to the compression mechanism (82) so that the refrigeration oil is returned only to the intermediate pressure compression chamber (73) in the compression mechanism (82). The refrigerating machine oil separated by the oil separator (33) returns to the compressor (14) in only one system of the oil return passage (34) , and the compressor (14) A sealed container-like casing (70) in which the compression mechanism (82) is accommodated, and a high-pressure space formed in the casing (70) and into which the refrigerant discharged from the compression mechanism (82) flows.

  In the first invention, the refrigerating machine oil separated by the oil separator (33) is returned to the intermediate pressure compression chamber (73) in the compression mechanism (82) of the compressor (14) through the oil return passage (34). It is trying to be. Therefore, even if the high-pressure refrigerant returns to the compressor (14) together with the refrigeration oil from the oil separator (33), the amount of the low-pressure refrigerant sucked by the compressor (14) does not change. Further, in the compression mechanism (82) constituted by the scroll fluid machine, the refrigerating machine oil flowing into the compression chamber (73) of intermediate pressure lubricates the sliding part along with the revolving motion of the movable scroll, and the center side Move to the high-pressure side located at The refrigerating machine oil that has flowed into the intermediate pressure compression chamber (73) has a higher temperature than when it is returned to the low pressure side of the compression mechanism (82), so that the viscosity does not increase. In other words, the position where the refrigerating machine oil is returned is close to the high pressure side, and the refrigerating machine oil having an appropriate viscosity is directly injected into the scroll, so that the refrigerating machine oil is more easily distributed to the high pressure side than when the refrigerating machine oil is returned to the low pressure side. ing.

  According to a second invention, in the first invention, an oil supply mechanism (104, 105) is provided for supplying the refrigerating machine oil stored in the high pressure space in the casing (70) to the low pressure side of the compression mechanism (82).

  In the second invention, the refrigerating machine oil stored in the high pressure space in the casing (70) is sent to the low pressure side of the compression mechanism (82) by the oil supply mechanism (104, 105). Further, the refrigeration oil from the oil separator (33) is supplied to an intermediate pressure compression chamber in the compression mechanism (82). In other words, in the second aspect of the invention, the refrigerating machine oil is supplied from two positions of the low pressure side and the intermediate pressure portion in the compression mechanism (82).

  According to a third invention, in the first or second invention, a liquid injection passage (30) for injecting a liquid refrigerant into the compression mechanism (82) is connected to the oil return passage (34). .

  In the third invention, the liquid injection passage (30) is connected to the oil return passage (34), and the refrigeration oil from the oil separator (33) is combined with the liquid refrigerant from the liquid injection passage (30) in the compressor ( It is possible to return to 14). This makes it possible to return the refrigeration oil from the oil separator (33) to a more appropriate viscosity by the liquid refrigerant and return it to the compressor (14).

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the compression mechanism (82) uses the oil return operation for returning the refrigeration oil from the oil separator (33) to the compression mechanism (82) and the liquid injection passage (30). The liquid injection operation for injecting the liquid refrigerant into the liquid crystal is performed at the same time.

  In the fourth invention, the oil return operation and the liquid injection operation are performed simultaneously. Accordingly, the refrigeration oil from the oil separator (33) is made to have a more appropriate viscosity by the liquid refrigerant from the liquid injection passage (30) and returns to the compressor (14).

  In the present invention, the oil of the refrigerating machine from the oil separator (33) is more easily distributed to the high pressure side of the compression mechanism (82) without changing the amount of the low pressure refrigerant sucked by the compressor (14). The refrigerating machine oil separated by the separator (33) is returned to the intermediate pressure compression chamber (73) in the compression mechanism (82). Therefore, since the amount of refrigerant circulating in the refrigerant circuit (4) does not change, the operating capacity of the refrigeration system (1) is different from returning the refrigeration oil from the oil separator (33) to the low pressure side of the compression mechanism (82). Does not drop. Moreover, since it becomes easy for refrigeration oil to spread to the high pressure side of the compression mechanism (82), it can suppress that refrigeration oil runs short on the high pressure side of the compression mechanism (82). Therefore, the lubrication of the compression mechanism (82) in the scroll compressor (14) can be improved without reducing the operating capacity of the refrigeration apparatus (1).

  In the second aspect of the invention, the refrigerating machine oil is supplied from the two positions of the low pressure side and the intermediate pressure portion in the compression mechanism (82) by the oil supply mechanism (104, 105) in the casing (70). The refrigeration oil stored in the high pressure space is sent to the low pressure side of the compression mechanism (82). That is, with the revolving motion of the movable side scroll, the refrigerating machine oil from the low pressure side moves to the high pressure side through the intermediate pressure part while lubricating the sliding part, and the refrigerating machine oil from the intermediate pressure part is It moves to the high pressure side while lubricating the sliding part. Therefore, the sliding portion can be evenly lubricated in the compression mechanism (82).

  In the third aspect of the invention, the oil return passage (34) is provided so that the refrigeration oil from the oil separator (33) can be returned to the compressor (14) with a more appropriate viscosity by mixing the refrigerant. ) Is connected to the liquid injection passage (30). Accordingly, the fluidity of the refrigerating machine oil from the oil separator (33) is increased, and the refrigerating machine oil is more easily distributed to the sliding part on the high pressure side of the compression mechanism (82), so that the compression mechanism in the compressor (14) The lubrication of (82) can be improved.

  In the fourth aspect of the invention, the oil return operation and the liquid injection operation are performed simultaneously so that the refrigeration oil from the oil separator (33) has a more appropriate viscosity and returns to the compressor (14). ing. Therefore, as in the third aspect, lubrication of the compression mechanism (82) in the compressor (14) can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

<Overall configuration of refrigeration equipment>
FIG. 1 is a refrigerant circuit diagram of a refrigeration apparatus (1) according to this embodiment. In this refrigeration system (1), one external unit (10) and two internal units (60) installed in parallel were connected by a liquid side communication pipe (2) and a gas side communication pipe (3). This is a so-called separate type refrigeration apparatus (1), and is configured to cool the inside of a refrigerated warehouse.

  The external unit (10) is provided with an external circuit (11), and each internal unit (60) is provided with an internal circuit (61). In this refrigeration system (1), each internal circuit (61) is connected to the external circuit (11) in parallel by the liquid side connecting pipe (2) and the gas side connecting pipe (3), thereby compressing the vapor. A refrigerant circuit (4) that performs a refrigeration cycle of the type is configured.

  A first closing valve (12) and a second closing valve (13) are provided at the end of the external circuit (11), respectively. One end of the liquid side communication pipe (2) is connected to the first closing valve (12). The other end of the liquid side connection pipe (2) is branched into two, and each is connected to the liquid side end of the internal circuit (61). One end of the gas side communication pipe (3) is connected to the second closing valve (13). The other end of the gas side communication pipe (3) is branched into two, and each is connected to the gas side end of the internal circuit (61).

《Outside unit》
The external circuit (11) of the external unit (10) includes three compressors (14a, 14b, 14c), an external heat exchanger (15), a receiver (16), a supercooling heat exchanger (17 ), A first external expansion valve (18), a second external expansion valve (19), a four-way switching valve (20), and an oil separator (33). The three compressors (14a, 14b, 14c) are composed of a variable capacity compressor (14a), a first fixed capacity compressor (14b), and a second fixed capacity compressor (14c), which are connected in parallel to each other. Has been.

  The variable capacity compressor (14a), the first fixed capacity compressor (14b), and the second fixed capacity compressor (14c) are all hermetic high-pressure dome type compression mechanisms composed of scroll fluid machines ( 82) is configured as a scroll compressor. Electric power is supplied to the variable capacity compressor (14a) via an inverter. The capacity of the variable capacity compressor (14a) can be changed by changing the output frequency of the inverter to change the rotational speed of the electric motor (85). On the other hand, in the first fixed capacity compressor (14b) and the second fixed capacity compressor (14c), the electric motor (85) is always operated at a constant rotational speed, and the capacities thereof cannot be changed. Yes. Details of the compressors (14a, 14b, 14c) will be described later.

  One end of the first discharge pipe (21a) is on the discharge side of the variable capacity compressor (14a), and one end of the second discharge pipe (21b) is on the discharge side of the first fixed capacity compressor (14b). One end of a third discharge pipe (21c) is connected to the discharge side of the fixed capacity compressor (14c). The first discharge pipe (21a) has a check valve (CV1), the second discharge pipe (21b) has a check valve (CV2), and the third discharge pipe (21c) has a check valve (CV3). Each is provided. The other ends of these discharge pipes (21a, 21b, 21c) are connected to the four-way switching valve (20) via the discharge junction pipe (21). These check valves (CV1, CV2, CV3) are valves that allow only the flow of refrigerant from the compressors (14a, 14b, 14c) toward the discharge junction pipe (21).

  One end of the first suction pipe (22a) is on the suction side of the variable capacity compressor (14a), and one end of the second suction pipe (22b) is on the suction side of the first fixed capacity compressor (14b). One end of a third suction pipe (22c) is connected to the suction side of the fixed capacity compressor (14c). The other ends of these suction pipes (22a, 22b, 22c) are connected to the four-way switching valve (20) via the suction junction pipe (22).

  The discharge junction pipe (21) is provided with an oil separator (33). The oil separator (33) is for separating the refrigerating machine oil from the refrigerant discharged from each compressor (14a, 14b, 14c). One end of an oil return pipe (34) that is an oil return passage is connected to the oil separator (33). The other end of the oil return pipe (34) is branched into a first oil return pipe (34a), a second oil return pipe (34b), and a third oil return pipe (34c). Each oil return pipe (34a, 34b, 34c) is connected to a compression chamber (73) of intermediate pressure in the compression mechanism (82) of each compressor (14a, 14b, 14c). Each oil return pipe (34a, 34b, 34c) is provided with a solenoid valve (SV1, SV2, SV3), respectively. In this embodiment, the refrigeration oil from the oil separator (33) is returned not to the suction pipe (22a, 22b, 22c) but to the intermediate pressure compression chamber (73), so that it is cooled by the low-pressure refrigerant and the viscosity increases. There is nothing to do.

  The external heat exchanger (15) is a cross-fin type fin-and-tube heat exchanger, and constitutes a heat source side heat exchanger. An external fan (23) is provided in the vicinity of the external heat exchanger (15). Although the external heat exchanger (15) is not illustrated, the heat transfer tubes are arranged in a plurality of paths, and the refrigerant pipes are branched and connected to the heat transfer tubes of the respective paths. And in this outside heat exchanger (15), heat exchange is performed between the outside air sent by the outside fan (23) and the refrigerant flowing through the heat transfer tube. One end of the external heat exchanger (15) is connected to the four-way switching valve (20). The other end of the external heat exchanger (15) is connected to the top of the receiver (16) via the first liquid pipe (24). The first liquid pipe (24) is provided with a check valve (CV4) that allows only the flow of the refrigerant in the direction toward the receiver (16).

  The supercooling heat exchanger (17) includes a high-pressure channel (17a) and a low-pressure channel (17b), and exchanges heat between the refrigerants flowing through the channels (17a, 17b). This supercooling heat exchanger (17) is constituted by, for example, a plate heat exchanger.

  The inflow end of the high-pressure channel (17a) is connected to the bottom of the receiver (16) via a refrigerant pipe. The outflow end of the high-pressure channel (17a) is connected to the first closing valve (12) via the second liquid pipe (25). The second liquid pipe (25) is provided with a check valve (CV5) that allows only the flow of refrigerant toward the liquid side communication pipe (2).

  On the other hand, the first branch pipe (26) branched from the second liquid pipe (25) on the upstream side of the check valve (CV5) is connected to the inflow end of the low pressure side flow path (17b). The first branch pipe (26) is provided with a first external expansion valve (18). The first outside expansion valve (18) is an electronic expansion valve whose opening degree can be adjusted. Further, at the outflow end of the low-pressure channel (17b), a liquid injection pipe (30) which is a liquid injection passage for injecting liquid refrigerant into the compression mechanism (82) of each compressor (14a, 14b, 14c) Are connected at one end.

  The other end of the liquid injection pipe (30) branches into a first liquid injection pipe (30a), a second liquid injection pipe (30b), and a third liquid injection pipe (30c). Each liquid injection pipe (30a, 30b, 30c) is connected between the solenoid valve (SV1, SV2, SV3) and the compressor (14a, 14b, 14c) in each oil return pipe (34a, 34b, 34c). ing. Each liquid injection pipe (30a, 30b, 30c) is provided with a solenoid valve (SV4, SV5, SV6).

  As described above, the receiver (16) is arranged between the external heat exchanger (15) and the supercooling heat exchanger (17), and temporarily stores the high-pressure refrigerant condensed in the external heat exchanger (15). Can be stored. One end of a gas vent pipe (27) is connected to the top of the receiver (16). The gas vent pipe (27) is provided with a check valve (CV7), and the other end is connected to the first discharge pipe (21a). This check valve (CV7) is a valve that allows only the flow of refrigerant from the receiver (16) to the discharge junction pipe (21).

  One end of the second branch pipe (28) is connected between the check valve (CV5) and the first closing valve (12) in the second liquid pipe (25). The other end of the second branch pipe (28) is connected between the check valve (CV4) and the receiver (16) in the first liquid pipe (24). The second branch pipe (28) is provided with a check valve (CV6) that allows only the flow of refrigerant toward the receiver (16).

  A third branch pipe (29) that bypasses the receiver (16) and the supercooling heat exchanger (17) is connected between the first liquid pipe (24) and the second liquid pipe (25). The third branch pipe (29) is connected between the external heat exchanger (15) and the check valve (CV4) in the first liquid pipe (24) and excessive in the second liquid pipe (25). It connects between the connection part of a cooling heat exchanger (17) and a 1st branch pipe (26). The third branch pipe (29) is provided with a second external expansion valve (19). The second external expansion valve (19) is an electronic expansion valve whose opening degree can be adjusted, and constitutes a heat source side expansion valve.

  A fourth branch pipe (31) that bypasses the supercooling heat exchanger (17) is connected between the first branch pipe (26) and the liquid injection pipe (30). The fourth branch pipe (31) is connected to the downstream side of the first external expansion valve (18) in the first branch pipe (26), and the compressors (14a, 14b, It is connected upstream of the branch point to 14c). The fourth branch pipe (31) is provided with a solenoid valve (SV7).

  The four-way selector valve (20) has the first port (P1) for the discharge junction pipe (21), the second port (P2) for the suction junction pipe (22), and the third port (P3) for external heat exchange. The container (15) has a fourth port (P4) connected to the second closing valve (13). The four-way selector valve (20) is in a first state in which the first port (P1) and the third port (P3) communicate with each other and the second port (P2) and the fourth port (P4) communicate with each other (see FIG. 1 and a second state (FIG. 1) in which the first port (P1) and the fourth port (P4) communicate with each other and the second port (P2) and the third port (P3) communicate with each other. In a state indicated by a broken line in FIG.

  The external circuit (11) is also provided with various sensors and pressure switches. Specifically, the suction junction pipe (22) is provided with a suction temperature sensor (35) and a suction pressure sensor (36). Each discharge pipe (21a, 21b, 21c) is provided with a high pressure switch (37a, 37b, 37c) and a discharge gas temperature sensor (38a, 38b, 38c). Each high pressure switch (37a, 37b, 37c) detects the discharge pressure, and urgently stops the refrigeration apparatus (1) as a protection device when the pressure is abnormally high. The first discharge pipe (21a), the second discharge pipe (21b), the third discharge pipe (21c), and the junction (the upstream end of the discharge junction pipe (21)) are provided with a discharge pressure sensor (43). Yes. Moreover, the liquid temperature sensor (45) is provided in the 2nd liquid pipe (25) of the external heat exchanger (15).

  Each of the sensors (35, 36, 38, 43, 44, 45) and the switch (37) are connected to a controller (50) that controls the operation of the refrigeration apparatus (1). This controller (50) is provided with each compressor (14a, 14b, 14c) and four-way switching valve (20) according to the output of each sensor (35, 36, 38, 43, 44, 45) and switch (37). ), Electronic expansion valves (18, 19), and solenoid valves (SV1 to SV7). The controller (50) controls the solenoid valves (SV1 to SV3) among these valves to refrigerate from the oil separator (33) to the compression mechanism (82) of each compressor (14a, 14b, 14c). The oil return operation to return the machine oil, the first external expansion valve (18) and the solenoid valve (SV4 to SV7) are controlled to use the liquid injection pipe (30) for each compressor (14a, 14b, 14c). The liquid injection operation for injecting the liquid refrigerant into the compression mechanism (82) is controlled. Details of the oil return operation and the liquid injection operation will be described later.

<Inside unit>
The two internal units (60) are similarly configured. In the internal circuit (61) of each internal unit (60), the drain pan heating pipe (62), the internal expansion valve (63), and the internal heat exchange in that order from the liquid side end to the gas side end A vessel (64) is provided.

  The internal expansion valve (63) is an electronic expansion valve whose opening degree can be adjusted, and constitutes a use side expansion valve. The internal heat exchanger (64) is a cross fin type fin-and-tube heat exchanger, and constitutes a use side heat exchanger. An internal fan (65) is provided in the vicinity of the internal heat exchanger (64). Although the internal heat exchanger (64) is not shown, the heat transfer tubes are arranged in a plurality of paths, and the refrigerant pipes are branched and connected to the heat transfer tubes of the respective paths. In the internal heat exchanger (64), heat is exchanged between the internal air sent by the internal fan (65) and the refrigerant flowing through the heat transfer tubes.

  A drain pan (66) provided with a drain pan heating pipe (62) is provided below the internal heat exchanger (64). This drain pan (66) collects frost and condensed water falling from the surface of the internal heat exchanger (64). In the drain pan (66), the ice mass generated by freezing the collected frost and dew condensation water is melted using the heat of the refrigerant flowing through the drain pan heating pipe (62).

  The internal circuit (61) is provided with three temperature sensors. Specifically, an evaporation temperature sensor (67) is provided in the heat transfer tube of the internal heat exchanger (64). A gas temperature sensor (68) is provided in the vicinity of the gas side end of the internal circuit (61). In the vicinity of the internal fan (65), an internal temperature sensor (69) is provided.

<Compressor configuration>
The structure of each compressor (14a, 14b, 14c) is demonstrated according to FIG.2 and FIG.3. In addition, since each compressor (14a, 14b, 14c) is comprised similarly, the structure of a variable capacity compressor (14a) is demonstrated here.

  The variable capacity compressor (14a) is configured as a so-called hermetic type. The variable capacity compressor (14a) includes a casing (70) that is vertically long and sealed. The casing (70) includes one barrel member (71) formed in a vertically long cylindrical shape, and end plate members (one each formed in a bowl shape and attached to the upper end and the lower end of the barrel member (71)). 72a, 72b). An oil sump for storing refrigerating machine oil is formed at the bottom of the casing (70).

  In the casing (70), a lower bearing member (81), an electric motor (85), and a compression mechanism (82) are arranged in order from the bottom to the top. A crankshaft (90) extending vertically is provided inside the casing (70).

  In the casing (70), the first suction pipe (22a) and the first oil return pipe (34a) penetrate the upper end plate member (72a) in the vertical direction, and the body member (71) passes through the first discharge pipe (21a). Penetrates horizontally. The first suction pipe (22a) and the first oil return pipe (34a) are connected to the compression mechanism (82), and the first discharge pipe (21a) has an inlet between the compression mechanism (82) and the electric motor (85). Open to the space.

  The crankshaft (90) includes a main shaft portion (91) and an eccentric portion (92). The upper end portion of the main shaft portion (91) has a slightly larger diameter. The eccentric part (92) is formed in a columnar shape having a smaller diameter than the main shaft part (91), and is erected on the upper end surface of the main shaft part (91). The eccentric portion (92) has an axis that is eccentric with respect to the axis of the main shaft portion (91).

  The lower bearing member (81) is fixed near the lower end of the body member (71) of the casing (70). A slide bearing is formed at the center of the lower bearing member (81), and this slide bearing rotatably supports the lower end portion of the main shaft portion (91).

  The electric motor (85) includes a stator (83) and a rotor (84). The stator (83) is fixed to the body member (71) of the casing (70). The stator (83) is electrically connected to a power supply terminal attached to the body member (71) of the casing (70). On the other hand, the rotor (84) is disposed inside the stator (83) and is fixed to the main shaft portion (91) of the crankshaft (90).

  A minute gap (air gap) is formed between the stator (83) and the rotor (84) so as to extend in the vertical direction (not shown). A core cut extending from the upper end surface of the stator (83) to the lower end surface is formed in the outer peripheral surface of the stator (83) (not shown). A plurality of core cuts are formed at predetermined intervals in the circumferential direction of the stator (83).

  The compression mechanism (82) includes a housing (77), a fixed scroll (75) disposed in close contact with the upper surface of the housing (77), and a movable scroll (76) meshing with the fixed scroll (75). I have. The fixed scroll (75) is fixed to the upper surface of the housing (77) by bolts.

  The housing (77) is formed in a relatively thick disk shape with a recessed central portion. The housing (77) is press-fitted and fixed to the casing (70) over the entire circumferential direction on the outer peripheral surface thereof. That is, the casing (70) and the housing (77) are in tight contact with each other over the entire circumference. The casing (70) is partitioned into a high-pressure space (100) below the housing (77) and a low-pressure space (101) above the housing (77). The main shaft portion (91) of the crankshaft (90) is inserted through the center portion of the housing (77). The housing (77) constitutes a bearing that rotatably supports the main shaft portion (91) of the crankshaft (90).

  The movable scroll (76) includes a movable side end plate (76b), a movable side wrap (76a), and a protrusion (76c). The movable side end plate (76b) is formed in a substantially disc shape. The movable side wrap (76a) is formed in a spiral wall shape with a fixed height standing on the upper surface of the movable side end plate (76b). The protruding portion (76c) is formed in a cylindrical shape and protrudes from the lower surface of the movable side end plate (76b). The movable side end plate (76b), the movable side wrap (76a), and the protrusion (76c) are integrally formed. The movable scroll (76) is supported by the housing (77) via the Oldham ring (79) and the eccentric part (92) of the crankshaft (90) is inserted into the protrusion (76c). The inside of the housing (77) is revolved without rotating by the rotation of 90).

  The fixed scroll (75) is formed in a relatively thick disk shape, and includes a fixed side end plate (75b) and a fixed side wrap (75a). The fixed side end plate (75b) is formed in a substantially disc shape. The fixed-side wrap (75a) is formed in a spiral wall shape with a fixed height standing on the lower surface of the fixed-side end plate (75b). The fixed side wrap (75a) is formed by carving the fixed scroll (75) from the lower surface side.

  In the compression mechanism (82), the fixed side wrap (75a) of the fixed scroll (75) and the movable side wrap (76a) of the movable scroll (76) are meshed with each other. The fixed wrap (75a) and the movable wrap (76a) mesh with each other, thereby forming a plurality of compression chambers (73) between the contact portions of both wraps (75a, 76a). The compression chamber (73) is configured to compress the refrigerant by the volume between the wraps (75a, 76a) contracting toward the center as the movable scroll (76) revolves.

  In addition, in each compressor (14a, 14b, 14c) of this embodiment, what is called an asymmetrical spiral structure is employ | adopted, and the number of windings (length of a spiral) with a fixed side wrap (75a) and a movable side wrap (76a). ) Is different. The plurality of compression chambers (73) includes a first compression chamber (73a) configured between an inner peripheral surface of the fixed side wrap (75a) and an outer peripheral surface of the movable side wrap (76a), and a fixed side wrap ( 75a) and a second compression chamber (73b) configured between the outer peripheral surface of the movable side wrap (76a).

  The outer end portion of the fixed wrap (75a) and the outer end portion of the movable wrap (76a) are positioned at the suction port (98) into which the first suction pipe (22a) is inserted. The suction port (98) intermittently communicates with each of the first compression chamber (73a) and the second compression chamber (73b) as the movable scroll (76) revolves. The suction port (98) is provided with a check valve (not shown) that allows only the refrigerant to be sucked into the compression chambers (73a, 73b) and prohibits the reverse flow of the refrigerant. Further, a communication port for communicating the suction port (98) and the low pressure space (101) is formed adjacent to the suction port (98).

  The fixed end plate (75b) of the fixed scroll (75) has a discharge passage (93) communicating with the compression chamber (73) and an enlarged recess (94) continuous with the discharge passage (93). . The discharge passage (93) is formed in the center of the fixed side end plate (75b). The discharge passage (93) intermittently communicates with each of the first compression chamber (73a) and the second compression chamber (73b) as the movable scroll (76) revolves. The enlarged concave portion (94) is formed in a concave shape extending from the central portion of the fixed side end plate (75b) toward the communication passage (103) described later. A lid (95) is fixed on the upper surface of the fixed scroll (75) so as to close the enlarged recess (94). And the muffler space (96) which silences the driving | running | working sound of a compression mechanism (82) is formed by covering a cover (95) to an expansion recessed part (94).

  An oil return port (99) for inserting the first oil return pipe (34a) is formed in the fixed side end plate (75b) of the fixed scroll (75). The oil return port (99) passes through the fixed side end plate (75b) at a portion where the enlarged recess (94) is not formed. The outlet end of the oil return port (99) opens so as to straddle the fixed side wrap (75a) at a position between the outer end and the inner end of each wrap (75a, 76a). That is, the first oil return pipe (34a) communicates with both the first compression chamber (73a) and the second compression chamber (73b), which are intermediate pressures between the low-pressure intake refrigerant and the high-pressure discharge refrigerant during operation. ing.

  In this embodiment, since the refrigerating machine oil from the oil separator (33) is returned to the compression chamber (73) of the intermediate pressure instead of the suction pipe (22a, 22b, 22c), the oil pressure from the oil separator (33) is increased together with the refrigerating machine oil. Even if the refrigerant returns to the compressor (14), the amount of low-pressure refrigerant sucked by the compressor (14) does not change. In addition, the position where the refrigerating machine oil is returned is close to the high pressure side of the compression mechanism (82), and the refrigerating machine oil with the appropriate viscosity is directly injected into the scroll, so that the refrigerating machine oil is less than when the refrigerating machine oil is returned to the low pressure side. It is easy to reach the high-pressure side. In the scroll compressor, the refrigerant discharged from the discharge passage (93) flows backward in the undercompressed state, making it difficult for the refrigerating machine oil to reach the center of the scroll. Since this is directly injected into the compression chamber (73) and supplied, the lubrication on the center side of the scroll when undercompressed is also improved.

  A communication passage (103) is formed in the compression mechanism (82) across the fixed scroll (75) and the housing (77). The communication passage (103) is formed by communicating a scroll-side passage (103a) formed in the fixed scroll (75) with a notch and a housing-side passage (103b) formed in the housing (77). . The upper end of the scroll side passage (103a) opens into the enlarged recess (94), and the lower end of the housing side passage (103b) opens at the lower end surface of the housing (77). That is, the communication path (103) communicates the muffler space (96) and the space between the compression mechanism (82) and the electric motor (85).

  A first oil supply passage (104) is formed in the crankshaft (90). The first oil supply passage (104) includes a main passage extending from the lower end surface of the crankshaft (90) to the upper end surface of the eccentric portion (92), and a branch passage extending from the main passage to each bearing surface. The movable end plate (76b) of the movable scroll (76) has a second oil supply passage (105 for supplying refrigeration oil to the sliding contact surface with the fixed scroll (75) on the outer peripheral side of the movable scroll (76). ) Is formed. The second oil supply passage (105) is formed in the radial direction from the annular oil groove (105a) formed on the sliding contact surface of the movable side end plate (76b) to the outside from the vicinity of the base end of the protrusion (76c). And an internal passage (105b) extending in the direction. The internal passage (105b) has an inlet end opened inside the protrusion (76c) and an outlet end opened in the oil groove (105a). The internal passage (105b) is formed in a spiral shape by inserting a screw member into a circular hole opened in the outer peripheral surface of the movable side end plate (76b). The first oil supply passage (104) and the second oil supply passage (105) constitute an oil supply mechanism.

-Operation of refrigeration equipment-
Below, the operation | movement operation | movement of the freezing apparatus (1) of this embodiment is demonstrated. In the cooling operation of the refrigeration apparatus (1), at least one of the three compressors (14a, 14b, 14c) is operated, and the internal unit (60) cools the interior.

<Cooling operation>
During the cooling operation, the four-way selector valve (20) is set to the first state. Further, the opening degree of the first external expansion valve (18) is adjusted as appropriate, while the second external expansion valve (19) is fully closed. In the internal circuit (61), the opening degree of the internal expansion valve (63) is appropriately adjusted. Each solenoid valve (SV1 to SV7) is opened and closed according to the operating state. When the compressors (14a, 14b, 14c) are operated in this state, the external heat exchanger (15) becomes a condenser in the refrigerant circuit (4), and each internal heat exchanger (64) is an evaporator. A vapor compression refrigeration cycle is performed. In the refrigerant circuit (4), the refrigerant flows in the direction of the solid arrow shown in FIG.

  Specifically, when the compressor (14a, 14b, 14c) is operated, the compressor (14a, 14b, 14c) sucks the low-pressure gas refrigerant, compresses it to a predetermined pressure, and discharges it. The high-pressure gas refrigerant discharged from the compressor (14a, 14b, 14c) flows into the oil separator (33) of the discharge merging pipe (21) through the discharge pipes (21a, 21b, 21c). In the oil separator (33), the refrigeration oil is separated from the flowing refrigerant. The separated refrigerating machine oil is stored at the bottom of the oil separator (33). The refrigerating machine oil at the bottom of the oil separator (33) passes through the oil return pipe (34) by the oil return operation, and the intermediate pressure compression chamber (73) of the compression mechanism (82) of the compressor (14a, 14b, 14c) Returned to

  The refrigerant flowing out from the oil separator (33) flows into the external heat exchanger (15) through the four-way switching valve (20). In the external heat exchanger (15), the refrigerant flowing in is condensed by exchanging heat with external air. Then, the condensed refrigerant flows into the receiver (16) through the first liquid pipe (24). In the receiver (16), the flowing liquid refrigerant is temporarily stored.

  The refrigerant that has flowed out of the receiver (16) passes through the high-pressure channel (17a) of the supercooling heat exchanger (17) and flows into the second liquid pipe (25). In the second liquid pipe (25), a part of the refrigerant flows into the first branch pipe (26) and is decompressed by the first external expansion valve (18). The remaining refrigerant flows into the liquid side connecting pipe (2).

  The refrigerant decompressed by the first external expansion valve (18) is used for gas injection or liquid injection into each compressor (14a, 14b, 14c). When the solenoid valve (SV7) of the fourth branch pipe (31) is closed, the supercooling heat exchanger (17) performs gas injection for supercooling the liquid refrigerant, and when it is open, the compressor ( Liquid injection for lowering the temperature of the discharged refrigerant 14a, 14b, 14c) is performed.

  Specifically, when the solenoid valve (SV7) of the fourth branch pipe (31) is closed, the refrigerant depressurized by the first external expansion valve (18) is the low pressure side of the supercooling heat exchanger (17). It circulates through the flow path (17b). At that time, in the supercooling heat exchanger (17), heat exchange is performed between the high-pressure refrigerant flowing in the high-pressure side passage (17a) and the low-pressure refrigerant flowing in the low-pressure side passage (17b). As a result, the refrigerant flowing through the high-pressure channel (17a) is supercooled, while the refrigerant flowing through the low-pressure channel (17b) evaporates. The gas refrigerant evaporated in the low-pressure channel (17b) passes through the suction pipes (22a, 22b, 22c) from the liquid injection pipe (30) and is intermediate in the compression mechanism (82) of the compressor (14a, 14b, 14c). Flows into the pressure compression chamber (73).

  On the other hand, when the solenoid valve (SV7) is in the open state, the liquid refrigerant (strictly gas-liquid two-phase refrigerant) depressurized by the first external expansion valve (18) is transferred from the low pressure side flow path (17b). A large amount flows into the fourth branch pipe (31) with little pressure loss. And it flows into the compression chamber (73) of the intermediate pressure in the compression mechanism (82) of a compressor (14a, 14b, 14c) through each suction pipe (22a, 22b, 22c) from a liquid injection pipe (30). Note that the amount of gas refrigerant or liquid refrigerant flowing through the liquid injection pipe (30) and sent to the compressor (14), that is, the injection amount, is freely adjusted by the opening of the first external expansion valve (18). .

  The refrigerant flowing into the liquid side communication pipe (2) is distributed to each internal circuit (61). The refrigerant flowing into the internal circuit (61) flows through the drain pan heating pipe (62). In the drain pan (66), the ice mass produced by freezing frost and condensed water that has fallen from the surface of the internal heat exchanger (64) by the refrigerant flowing through the drain pan heating pipe (62) is melted. At that time, the refrigerant flowing through the drain pan heating pipe (62) is cooled by the frost and ice blocks and is supercooled.

  The refrigerant that has flowed out of the drain pan heating pipe (62) passes through the internal expansion valve (63) and is decompressed, and then flows into the internal heat exchanger (64). In the internal heat exchanger (64), the refrigerant flowing in exchanges heat with the internal air and evaporates. As a result, the air in the refrigerator warehouse is cooled.

  The refrigerant evaporated in each internal heat exchanger (64) flows into the gas side connecting pipe (3) and then flows into the external circuit (11). The refrigerant flowing into the external circuit (11) flows into the suction junction pipe (22) through the four-way switching valve (20), and is connected to the variable capacity compressor (14a), the first fixed capacity compressor (14b), 2 Sucked into the fixed capacity compressor (14c).

<Defrost operation>
In this refrigeration apparatus (1), when the internal heat exchanger (64) forms frost during the refrigeration operation, the defrost operation is performed to remove the frost. During the defrosting operation, the internal heat exchangers (64) are defrosted simultaneously.

  In the external circuit (11) during the defrost operation, the four-way selector valve (20) is set to the second state. Moreover, while the 1st external expansion valve (18) will be in a fully closed state, the opening degree of a 2nd external expansion valve (19) is adjusted suitably. In the internal circuit (61), the internal expansion valve (63) is fully opened. When the compressors (14a, 14b, 14c) are operated in this state, the external heat exchanger (15) becomes an evaporator in the refrigerant circuit (4), and each internal heat exchanger (64) is a condenser. A vapor compression refrigeration cycle is performed. In the refrigerant circuit (4), the refrigerant flows in the direction of the wavy arrow shown in FIG.

<Compressor operation>
When the electric motor (85) is driven to rotate the crankshaft (90), the movable scroll (76) does not rotate with respect to the fixed scroll (75) and only revolves. As a result, the low-pressure refrigerant from the suction pipe (22) is sucked into the compression chamber (73) on the peripheral side from the suction port (99) and gradually approaches the center side of the compression mechanism (82). It is compressed by the volume change of the compression chamber (73). Then, the compressed refrigerant becomes high pressure and is discharged into the muffler space (96) through the discharge passage (93) on the center side of the compression chamber (73). The refrigerant flows into the space between the compression mechanism (82) and the electric motor (85) from the muffler space (96) through the communication passage (103), and is discharged from the discharge pipe (21).

  The flow of refrigeration oil in the compression chamber (73) will be described. The refrigerating machine oil in the oil reservoir is pressurized by the high-pressure refrigerant, flows into the main passage of the first oil supply passage (104), and flows upward toward the upper end of the crankshaft (90). At that time, a part of the refrigerating machine oil is supplied from the branch passage to each bearing surface. The remaining refrigerating machine oil flows out from the upper end of the eccentric part (92) of the crankshaft (90), and a part thereof flows into the second oil supply passage (105). The refrigeration oil flowing into the second oil supply passage (105) is supplied from the oil groove (105a) to the compression chamber (73) on the low pressure side. At this time, the thrust load acting on the sliding contact surface with the fixed scroll (75) on the outer peripheral side of the movable scroll (76) is relieved by the refrigerating machine oil from the oil groove (105a).

  The refrigerating machine oil supplied to the compression chamber (73) on the low pressure side gradually moves toward the center of the compression mechanism (82) while lubricating the sliding portion as the movable scroll (76) revolves. Further, the refrigeration oil from the oil separator (33) is injected from the outlet end of the oil return pipe (34) by the oil return operation and supplied to the compression chamber (73) of intermediate pressure. This refrigerating machine oil also gradually moves toward the center of the compression mechanism (82) while lubricating the sliding portion as the movable scroll (76) revolves. These refrigeration oils are discharged from the discharge passage (93) together with the refrigerant. The refrigeration oil discharged from the discharge passage (93) is partly separated from the refrigerant by the inner wall of the casing (70), etc., flows into the oil sump at the bottom of the casing (70) through the air gap and core cut, The fuel is again supplied from the first oil supply passage (104) to the compression mechanism (82). The refrigeration oil that has not been separated from the refrigerant is discharged from the discharge pipe (21) to the refrigerant circuit (4).

<Operation of controller>
In this embodiment, in the cooling operation, the controller (50) controls the operating capacity of the compressors (14a, 14b, 14c) and the cooling capacity by adjusting the opening of the internal expansion valve (63). The return operation and liquid injection operation are controlled.

  First, control of the oil return operation will be described. The controller (50) estimates the amount of refrigerating machine oil remaining in each compressor (14a, 14b, 14c) based on the operating rate and oil rise rate of each compressor (14a, 14b, 14c) and returns the oil. It is configured to control the operation. Here, the operating rate is a numerical value calculated so as to be proportional to the amount of refrigerant discharged from the compressor (14a, 14b, 14c). The operation rate of the variable capacity compressor (14a) is calculated from the operation time and the output frequency of the inverter. The operating rates of the first fixed capacity compressor (14b) and the second fixed capacity compressor (14c) are calculated from the operating time. The oil climb rate is a numerical value indicating the degree of decrease in the refrigeration oil during a certain time. The oil climb rate of the variable capacity compressor (14a) is a value proportional to the output frequency of the inverter. The oil rising rate of the first fixed capacity compressor (14b) and the second fixed capacity compressor (14c) is a constant value.

  When the amount of refrigerating machine oil remaining in the compressor (14a, 14b, 14c) falls below a predetermined value, the controller (50) controls the solenoid valves (SV1, SV2, SV2) corresponding to the compressor (14a, 14b, 14c). Execute oil return operation with SV3) open. The controller (50) sends the compressor (14a, 14b, 14c) from the oil return pipe (34) based on the high / low pressure difference that is the difference between the measured value of the suction pressure sensor (36) and the measured value of the discharge pressure sensor (43). Estimate the amount of refrigerating machine oil returning to), and determine the time for the oil return operation.

  Next, the control of the liquid injection operation will be described. The controller (50) is configured to control the liquid injection operation based on the measured value of the discharge gas temperature sensor (38, 40, 42) and the measured value of the suction pressure sensor (36). Specifically, the controller (50) estimates the circulation amount of the refrigerant from the measured value of the suction pressure sensor (36). Then, a difference between the temperature of the discharge pipe (22a, 22b, 22c) and the temperature of the outlet of the compression mechanism (82) is estimated from the circulation amount of the refrigerant, and the temperature of the outlet of the compression mechanism (82) is estimated. When the estimated temperature at the outlet of the compression mechanism (82) exceeds a predetermined value, the controller (50) will detect the solenoid valves (SV4, SV5, SV6) and solenoid valves (SV4, SV5, SV6) corresponding to the compressors (14a, 14b, 14c) SV7) is opened and the liquid injection operation is executed.

  The controller (50) is also configured to simultaneously perform a liquid injection operation when performing the oil return operation. That is, the controller (50) includes the compressor (14a, 14b, Perform liquid injection operation for 14c). The reason why the oil return operation and the liquid injection operation are performed simultaneously is to make the refrigerating machine oil returned to the compressor (14a, 14b, 14c) from the oil separator (33) have an appropriate viscosity. If the oil return operation and gas injection are performed simultaneously, abnormal noise is generated when the gas refrigerant from the oil return pipe (34) and the gas refrigerant from the liquid injection pipe (30) mix. In the form, this noise is not generated.

  The controller (50) may perform the oil return operation when the compressors (14a, 14b, 14c) are started. When the compressor (14a, 14b, 14c) is started, the viscosity of the refrigerating machine oil stored in the bottom of the casing (70) is high, so that the lubricity of the compression mechanism (82) is lowered. For this reason, it is possible to improve the lubricity of the compression mechanism (82) by supplying the refrigeration oil from the oil separator (33) to the compression chamber (73) of intermediate pressure. Note that the liquid injection operation is performed simultaneously with the oil return operation, as in the operation.

-Effect of the embodiment-
In this embodiment, the refrigeration oil from the oil separator (33) further reaches the high pressure side of the compression mechanism (82) without changing the amount of low-pressure refrigerant sucked by each compressor (14a, 14b, 14c). In order to facilitate the operation, the refrigerating machine oil separated by the oil separator (33) is returned to the intermediate pressure compression chamber (73) in the compression mechanism (82). Therefore, since the amount of refrigerant circulating in the refrigerant circuit (4) does not change, the operating capacity of the refrigeration system (1) is different from returning the refrigeration oil from the oil separator (33) to the low pressure side of the compression mechanism (82) Does not drop. Further, since the refrigeration oil can easily reach the high pressure side of the compression mechanism (82), it is possible to suppress the shortage of the refrigeration oil on the high pressure side of the compression mechanism (82). Therefore, the lubrication of the compression mechanism (82) in each compressor (14a, 14b, 14c) can be improved without reducing the operating capacity of the refrigeration apparatus (1).

  The scroll compressor includes a type in which the movable side wrap (76a) and the fixed side wrap (75a) come into contact with each other during the revolving motion of the movable scroll (76), and the movable side wrap (76a) and the fixed side. There is a type in which a gap is formed between these wraps (75a, 76a) without contact with the wraps (75a). In the case of the latter scroll compressor, if the refrigerating machine oil is insufficient, the sealing performance of the gap is lowered, so that there is a problem that loss due to refrigerant leakage increases and compression efficiency is lowered. When the latter scroll compressor is applied to the present embodiment, refrigerant shortage in the compression mechanism (82) is suppressed, so that loss due to refrigerant leakage can be reduced and compression efficiency can be improved.

  Further, in the present embodiment, the first oil supply passage (104) and the second oil supply passage (105) are supplied so that the refrigerating machine oil is supplied from two positions of the low pressure side and the intermediate pressure portion in the compression mechanism (82). ), The refrigerating machine oil stored at the bottom of the casing (70) is sent to the low pressure side of the compression mechanism (82). That is, with the revolving motion of the movable side scroll, the refrigerating machine oil from the low pressure side moves to the high pressure side through the intermediate pressure part while lubricating the sliding part, and the refrigerating machine oil from the intermediate pressure part is It moves to the high pressure side while lubricating the sliding part. Therefore, the sliding portion can be evenly lubricated in the compression mechanism (82).

  Further, in the present embodiment, the oil return is performed so that the refrigerant oil from the oil separator (33) can be made to have a more appropriate viscosity and returned to the compressors (14a, 14b, 14c) by mixing the refrigerant. The liquid injection pipe (30) is connected to the pipe (34) to perform the oil return operation and the liquid injection operation simultaneously. Accordingly, the fluidity of the refrigerating machine oil from the oil separator (33) is increased, and the refrigerating machine oil is more easily distributed to the sliding portion on the high-pressure side of the compression mechanism (82), so that each compressor (14a, 14b, The lubrication of the compression mechanism (82) in 14c) can be improved.

<< Other Embodiments >>
About the said embodiment, it is good also as the following structures.

  In the above embodiment, the liquid injection pipe (30) is connected to the oil return pipe (34), but may be connected to each suction pipe (22a, 22b, 22c).

  Moreover, in the said embodiment, although the three compressors (11A, 11B, 11C) were provided in the external unit (10), the number of compressors can also be changed suitably.

  Moreover, in the said embodiment, although the compressor (14a, 14b, 14c) employ | adopted the asymmetrical spiral structure, you may employ | adopt a symmetrical spiral structure. In this case, two intermediate pressure ports (99) are formed at positions sandwiching the discharge passage (93).

  In addition, the above embodiment is an essentially preferable illustration, Comprising: It does not intend restrict | limiting the range of this invention, its application thing, or its use.

  As described above, the present invention is useful for a refrigeration apparatus including an oil separator for returning refrigeration oil contained in refrigerant discharged from a compressor to the compressor.

It is a refrigerant circuit figure of the refrigerating device concerning the embodiment of the present invention. It is a longitudinal cross-sectional view of the compressor of embodiment. It is a cross-sectional view of the fixed scroll of the compressor of the embodiment.

1 Refrigeration equipment
4 Refrigerant circuit
14 Compressor
30 Liquid injection pipe (Liquid injection passage)
33 Oil separator
34 Oil return pipe (oil return passage)
70 casing
73 Compression chamber
82 Compression mechanism
104 1st oil supply passage (oil supply mechanism)
105 Second oil supply passage (oil supply mechanism)

Claims (4)

A compressor (14) having a compression mechanism (82) constituted by a scroll fluid machine, an oil separator (33) for separating refrigeration oil from refrigerant discharged from the compressor (14), and the oil separator (33 A refrigerating apparatus comprising a refrigerant circuit (4) provided with an oil return passage (34) for returning the refrigeration oil separated in (1) to the compressor (14),
The oil return passage (34) is connected to the compression mechanism (82) so as to return the refrigerating machine oil only to the intermediate pressure compression chamber (73) in the compression mechanism (82), and the oil separator (33) The refrigerating machine oil separated in step 1 returns to the compressor (14) through only one system of the oil return passage (34),
The compressor (14) includes an airtight container-like casing (70) in which the compression mechanism (82) is housed, and a discharge refrigerant of the compression mechanism (82) formed in the casing (70). A refrigeration apparatus comprising an inflowing high-pressure space. In claim 1,
A refrigerating apparatus comprising an oil supply mechanism (104, 105) for supplying refrigerating machine oil stored in a high pressure space in the casing (70) to a low pressure side of the compression mechanism (82). In claim 1 or 2,
A refrigeration apparatus, wherein a liquid injection passage (30) for injecting a liquid refrigerant to the compression mechanism (82) is connected to the oil return passage (34). In claim 3,
An oil return operation for returning the refrigeration oil from the oil separator (33) to the compression mechanism (82), and a liquid injection operation for injecting a liquid refrigerant into the compression mechanism (82) using the liquid injection passage (30). A refrigeration apparatus characterized by being performed simultaneously.

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