JP2005201480A - Refrigerator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a refrigerator comprising a reciprocating compressor having a two-stage compression mechanism holding the amount of lubricating oil in a case. <P>SOLUTION: This refrigerator comprises the two-stage compressor 30 wherein a first compression part 32a compresses refrigerant gas sucked into a closed case 31 from the front evaporator 24 side, to discharge it to a second compression part 32b, and the second compression part 32b compresses refrigerant gas sucked from the rear evaporator 26 side, and the refrigerant gas discharged from the first compression part 32a, to discharge them into a refrigerating cycle. During the operation of the compressor 30 (S3), the flow of refrigerant flowing to the rear evaporator 26 is intercepted or reduced by a flow regulator 22. Lubricating oil 60 in cycle piping on the rear evaporator 26 side is thereby recovered into the two-stage compressor 30 (S7, S8). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a refrigerator provided with a compressor having a two-stage compression mechanism.

  A refrigerator using a compressor having a two-stage compression mechanism in a refrigeration cycle having a plurality of evaporators having different evaporation temperatures has been considered (see, for example, Patent Document 1). Hereinafter, an example of the above configuration will be described with reference to FIGS.

  FIG. 3 is a schematic diagram of the refrigeration cycle. A discharge pipe P that discharges the refrigerant compressed by the compressor 30 to the condenser 21 side includes a flow rate adjusting device 22 that adjusts the flow rate of refrigerant flowing through the condenser 21, a high-temperature evaporator 26 and a low-temperature evaporator 24, which will be described later. Are connected in series. On one downstream side of the flow rate adjusting device 22, there are a high temperature side capillary tube 25, a high temperature evaporator 26 having a relatively high evaporation temperature for cooling the refrigerator compartment, a downstream side of the high temperature evaporator 26, and a compressor 30. An intermediate pressure side suction pipe H connected to the suction side is connected in series, and on the other side, a low temperature side capillary tube 23, a low temperature evaporator 24 having a relatively low temperature for cooling the freezer compartment, and a compressor 30, for example. The low-pressure side suction pipe L connected in the low-pressure case is connected in series.

  4 and 5 are a cross-sectional view of the compressor as viewed from above and a vertical cross-sectional view as viewed from the front. In the sealed case 31 of the compressor 30, a compression unit 32 is provided on the upper side, and an electric unit 50 is provided on the lower side (not shown).

  Here, the compression unit 32 employs a so-called reciprocating compressor, and includes a first compression unit 32a located on the left side of the drawing and a second compression unit 32b located on the right side.

  A pivotal support hole 31b is provided at the center of the frame 33, and a rotary shaft 34 is rotatably provided in the pivotal support hole 31b. The upper end of the rotating shaft 34 is integrally provided with a flange portion 34a mounted on the upper surface of the frame 33, and the upper portion of the flange portion 34a has a central axis that is eccentric from the central axis of the rotating shaft 34 by a predetermined amount. The eccentric shaft portion 34b is integrally formed.

  When the rotary shaft 34 is driven to rotate, the flange portion 34a rotates in a sliding state on the upper surface of the frame 33, and the eccentric shaft portion 34b rotates eccentrically with respect to the center of the rotary shaft 34.

  The first compression unit 32 a and the second compression unit 32 b are mounted on the upper surface of the frame 33. Each compression part 32a, 32b is arrange | positioned in the position which opposes substantially 180 degrees via the said eccentric shaft part 34b, and is provided with cylinder 35a, 35b arrange | positioned horizontally with respect to an axial direction, respectively.

  Inside the cylinders 35a and 35b are compression chambers 37a and 37b in which the pistons 36a and 36b are reciprocally accommodated. One ends of connecting rods 38a and 38b are connected to the pistons 36a and 36b, respectively, and the pistons 36a and 36b are connected to the eccentric shaft portion 34b via the connecting rods 38a and 38b.

  Ball joints k are formed at the tips of the connecting rods 38a and 38b, and a ball joint type connection in which the ball k is engaged and held by a ball receiving portion m formed by caulking inside the pistons 36a and 36b. doing. The ball part k and the ball receiving part m may be provided opposite to the connecting rods 38a and 38b and the pistons 36a and 36b, respectively.

  The other ends of the connecting rods 38a and 38b form end portions 39a and 39b that are rotatably fitted to the eccentric shaft portion 34b, and have a double-fitting structure with respect to the eccentric shaft portion 34b.

  The low pressure side suction pipe L is connected so that the refrigerant gas from the low-temperature evaporator 24 is sucked into the sealed case 31, and the left wall of the first compression portion 32 a sucks the refrigerant gas in the sealed case 31. A first suction port 40a is provided. Moreover, the 1st discharge port 41a which discharges the refrigerant gas compressed by this compression part 32a to the 2nd compression part 32b is provided.

  On the other hand, the intermediate pressure side suction pipe H is connected to the second compression portion 32b so that the refrigerant gas from the high temperature evaporator 26 is sucked into the second compression portion 32b. Specifically, the refrigerant gas merges from the first discharge port 41a and the intermediate pressure side suction pipe H, and is sucked from the second suction port 40b provided in the right wall of the second compression section 32b. In the 2nd compression part 32b, the said mixed gas sucked in is compressed, and it discharges to the condenser 2 via the discharge pipe P from the 2nd discharge port 41b.

  With respect to the compression unit 32, the electric unit 50 includes a rotor 51 fitted in a portion projecting downward from the frame 33 of the rotating shaft 34, and a narrow gap between the circumferential surface of the rotor 51 and the rotor 51. The stator 52 is provided with a peripheral surface and is suspended and fixed from the frame 33.

  Further, as shown in FIG. 5, for example, about 250 g of lubricating oil 60 is stored up to the X-ray on the bottom surface of the sealed case 31. Inside the rotary shaft 34, a vertically long lower oil supply passage 61 is provided at a position eccentric from the shaft center, and a lower opening 62 communicating with the lower oil supply passage 61 is provided on the outer periphery of a substantially intermediate position. . A spiral groove 63 is provided on the outer peripheral surface of the rotating shaft 34 from the lower opening 62 so that the lubricating oil flows upward. An upper opening 64 and an upper oil supply passage 65 for guiding the lubricating oil 60 from the groove 63 to the upper surface opening 66 by centrifugal force are provided inside the flange portion 34a and the eccentric shaft portion 34b of the rotating shaft 34. With these configurations, when the rotating shaft 34 rotates, the lubricating oil 60 is sucked upward from the lower end portion 34c of the rotating shaft 34 by centrifugal force, and is scattered from the upper surface opening 66 of the rotating shaft 34 to supply oil to the compression portion 32 and the like. It is supposed to be.

According to the above-described configuration, in a state where the refrigerant flows in both the evaporators 24 and 26 (full open mode), the rotating shaft 34 is rotationally driven by energization of the electric unit 50, and the pistons 36 a and 36 b The compression units 32a and 32b perform the reverse steps of compression and suction to circulate the refrigerant in the refrigeration cycle to cool the room, and the lubricating oil 60 is appropriately supplied to the compression unit 32. Thus, wear between the cylinders 35a and 35b and the pistons 36a and 36b is prevented.
JP 2003-148330 A

  In general, in a refrigerator using a reciprocating compressor having the above compression mechanism, the refrigerant gas in the sealed case 31 is sucked from the first suction port 40a, so that the lubricating oil 60 is mixed with the refrigerant gas, and each of the compression portions 32a, 32b will be discharged to the refrigeration cycle together with the refrigerant gas.

  In this case, on the low-temperature evaporator 24 side, even if the lubricating oil 60 is discharged into the pipe, it is sucked together with the refrigerant gas from the low-pressure side suction pipe L into the sealed case 31. However, on the high temperature evaporator 26 side, the refrigerant gas from the high temperature evaporator 26 is directly sucked into the second compression portion 32b via the intermediate pressure side suction pipe H, so The lubricating oil 60 mixed in does not flow into the sealed case 31.

  At this time, since the lubricating oil 60 is sucked into the second compression portion 32b, it is discharged again to the condenser side 21 together with the refrigerant gas, and returned to the sealed case 31 if it flows to the low temperature evaporator 24 side. In general, since the high-temperature side capillary tube 25 is set to be narrower than the low-temperature side capillary tube 23, the refrigerant flows more easily on the high-temperature evaporator 26 side, and the lubricating oil 60 mixed with the refrigerant is also contained in the high-temperature evaporator 4. Since it flows a lot to the side, it gradually accumulates in the pipe without flowing into the sealed case 31.

  That is, as the cooling operation for flowing the refrigerant to the high temperature side evaporator 26 becomes longer, there is a problem that the lubricating oil 60 in the sealed case 31 decreases, and the lower end opening 34c of the rotating shaft 34 that sucks the lubricating oil 60 For example, when the amount of the lubricating oil 60 decreases to the position of the Y line, the lubricating oil 60 cannot be supplied to the compressing portion 32, so that the cylinders 35a and 35b and the pistons 36a and 36b are worn and the compressing portion 32 is damaged. There is a risk of developing.

  In view of the above problems, an object of the present invention is to provide a refrigerator including a compressor having a two-stage compression mechanism that holds the amount of lubricating oil in the case.

  In order to solve the above problems, a refrigerator according to the present invention includes a low-temperature evaporator and a high-temperature evaporator, which are disposed in a refrigerator main body and having different evaporation temperatures, and a refrigerant connected to at least the upstream side of the high-temperature evaporator. A two-stage device having a flow rate adjusting device for blocking the flow or changing the flow rate, a first compression portion and a second compression portion provided in the sealed case, and an oil supply means for supplying lubricating oil to the first and second compression portions. A refrigeration cycle is formed from the compressor, the first compression section compresses and discharges the refrigerant gas sucked into the sealed case from the low temperature evaporator side, and the second compression section is sucked from the high temperature evaporator side. The refrigerant gas and the refrigerant gas discharged from the first compression unit are compressed and protruded into the refrigeration cycle, and the refrigerant flow flowing to the high-temperature evaporator during the operation of the two-stage compressor is shut off by the flow rate adjusting device. By reducing Hot evaporator side cycle lubricating oil in the piping, characterized in that so as to recover the two-stage compressor.

  According to the above invention, even if the lubricating oil gradually accumulates in the piping on the high temperature evaporator side and the amount of oil in the compressor sealed case decreases, the refrigerant flowing into the high temperature evaporator during operation of the two-stage compressor is reduced. By cutting off or reducing the flow rate, the lubricating oil collected in the pipe on the high temperature evaporator side is recovered in the second compression section and returned to the sealed case through the pipe on the low temperature evaporator side. Therefore, damage to the compression part or the like can be prevented.

  An embodiment of the present invention will be described below with reference to the drawings. In addition, the same code | symbol is attached | subjected to the same structure as the conventional structure, and the description is abbreviate | omitted.

  As shown in FIG. 2 which is a longitudinal sectional view of the refrigerator according to the present invention, the refrigerator main body 1 has a rectangular box-shaped heat insulation box 2 filled with a heat insulating material 2c between the outer box 2a and the inner box 2b. In order from the top, it has a refrigerator compartment 3, a vegetable compartment 4, a switching chamber 5, and a freezer compartment 6. Although not shown in particular, an ice making chamber is provided with the switching chamber 5. The front opening of the main body 1 is provided with doors 7 to 10 that sequentially close the storage chambers 3 to 6 in an openable manner.

  The refrigerator compartment 3 and the vegetable compartment 4 are maintained in a temperature range of approximately 1 to 5 degrees, and each is partitioned by a partition plate 11. A high temperature evaporator 26 (hereinafter referred to as “R EVA”) that cools the refrigerator compartment 3 and the vegetable compartment 4 is provided on the back of the vegetable compartment 4, and a refrigerator compartment fan 13 (hereinafter referred to as “R”) is provided on the top thereof. (Referred to as a fan). When this R fan 13 is operated, the cold air generated by the R evaporator 26 is supplied to the refrigerator compartment 3 and the vegetable compartment 4 to cool each chamber, and the cooled cold air is returned to the R evaporator 26 again. It is designed to exchange heat.

  On the other hand, the freezer compartment 6 and the switching chamber 5 are each partitioned by a heat insulating partition wall 12, the freezer compartment 6 is maintained in a temperature range of −18 to −25 degrees, and the switching chamber 5 has various set temperatures. It is controlled to be held in the belt. A low-temperature evaporator 24 (hereinafter referred to as “F-eva”) having an evaporation temperature set lower than that of the R-eva 26 is provided on the rear surfaces of the switching chamber 5 and the freezer compartment 6. , Called F fan). When the F fan 14 is operated, the cold air generated by the F EVA 24 is supplied to the switching chamber 5 and the freezing chamber 6 to cool each chamber, and the cooled cold air is again heat-exchanged by the F EVA 24. It has become so.

  A machine room 15 is provided at the bottom of the back surface of the main body 1, and a compressor 30 and a heat radiating fan 16 (hereinafter referred to as a C fan) for radiating heat from the compressor 30 are provided therein.

  The refrigeration cycle according to the present invention has the same configuration as that described in the prior art, but the flow rate adjusting device 22 changes the valve opening by the rotation of the stepping motor, and flows into the F and R EVAs 24 and 26. In addition to adjusting the flow rate, the flow path can be switched, fully opened, fully closed, and the like. The flow rate adjusting device 22 is not limited to the above configuration, and various changes such as a configuration using a solenoid can be made. Furthermore, in the description of the present invention, a description will be given of a configuration using a three-way valve. However, a two-way valve may be provided on both the F EVA 24 and the R EVA 26, or a two-way valve may be provided only on the R EVA 26.

  Next, a normal cooling operation in the refrigerator of the present invention will be described. In a normal cooling operation (hereinafter referred to as a simultaneous cooling mode), the flow rate adjusting device 22 is fully opened, the refrigerant is supplied to both the evaporators 24 and 26, the R fan 13 and the F fan 14 are rotated, and the chambers 3, 4, 5, 6 are rotated. Cool inside. When each of the chambers 3, 4, 5, and 6 becomes lower than the lower limit temperature set in each chamber (for example, -1K with respect to the set target temperature, respectively), the compressor 40, R The fan 13 and the F fan 14 are stopped to stop the cooling.

  In this case, if only the room temperature of either the refrigerating room 3 or the freezing room 6 falls below the lower limit temperature, the compressor 40 is not stopped and the evaporator that is not cooled by the operation of the flow control device 22 is used. A large amount of refrigerant is allowed to flow or the cooling fan is stopped from rotating. At this time, the compressor 40 may also be stopped, but the upper limit temperature set in each room (for example, with respect to the set target temperature, respectively) so that the uncooled room does not become insufficiently cooled. It is preferable to stop only when + 1K) or less.

  Conversely, when only the room temperature of either the refrigerator compartment 3 or the freezer compartment 6 is equal to or higher than the upper limit temperature and the other chamber is lower than the lower limit temperature, the compressor 40 is not stopped and the flow rate adjusting device 22 is not stopped. Prioritizing cooling that is not cooled by the operation, a large amount of refrigerant is allowed to flow through the evaporator, and rotation of the cooling fan is stopped. At this time, if the refrigerating chamber 3 is lower than the lower limit temperature, the food may freeze if further cooling is performed. Therefore, the cooling chamber 3 is shifted to the F cooling mode to be described later, and the refrigerating chamber 3 is not cooled. Preferably only 6 is cooled.

  Next, the R cooling mode for cooling only the refrigerator compartment 3 and the vegetable compartment 4 and the F cooling mode for cooling only the switching chamber 5 and the freezer compartment 6 will be described.

  The R cooling mode is a mode in which only the refrigerator compartment 3 and the vegetable compartment 4 are mainly cooled by operating the flow rate adjusting device 22 so as to block the refrigerant flow to the F-evapor 24 or to allow some refrigerant to flow. At this time, the R fan 13 is operated to cool the room, and the F fan 14 is stopped. The R fan 13 and the F fan 14 are operated or stopped as necessary.

  When transitioning to this mode, transition should be made when only the refrigerator compartment 3 and the vegetable compartment 4 that do not require cooling such as the freezer compartment 6 have risen in temperature, or when the F-eva 24 is defrosted. In addition, when shifting from this mode to another cooling mode, when the room temperature of the refrigerator compartment 3 and the vegetable compartment 4 is lower than the lower limit temperature, or the room temperature of the freezer compartment 6 is higher than the upper limit temperature. It is preferable to shift to such a case.

  The F cooling mode is a mode in which only the switching chamber 5 and the freezing chamber 6 are mainly cooled by operating the flow rate adjusting device 22 so that the flow of the refrigerant to the R evaporator 26 is interrupted or slightly flows. At this time, both the F fan 14 and the R fan 13 are operated. The F fan 14 cools the room by rotation, and the R fan 13 promotes defrosting of the R evaporator 26 by rotation to reduce the adsorbed moisture to the refrigerator compartment 3 or the like. The R fan 13 and the F fan 14 are operated or stopped as necessary. The R fan 13 is operated after a predetermined time of 10 minutes, for example, or after the R EVA 26 reaches 3 ° C., for example. Then, it may be considered that the defrosting is finished and stopped. In addition, when the heater for performing defrosting is provided in R EVA 26, R fan 13 does not need to be operated.

  When shifting to this mode, it is preferable to shift when the temperature of the freezer compartment 6 or the like that does not require cooling of the refrigerator compartment 3 and the vegetable compartment 4 rises, or when defrosting the R-eva 26, When shifting from this mode to another cooling mode, when the room temperature of the freezer compartment 6 or the like falls below the lower limit temperature, or when the room temperature of the refrigerator compartment 3 or vegetable compartment 4 exceeds the upper limit temperature, etc. It is preferable to migrate. Further, as described above, the transition may not be made until the defrosting of the R EVA 26 is completed.

  Next, a control method (hereinafter referred to as “lubricating oil recovery mode”) for returning the lubricating oil 60 accumulated on the R EVA 26 side of the present invention into the compressor 40 will be described with reference to the flowchart of FIG.

  In step 1, it is determined whether or not cooling is required in the refrigerator compartment 3 or the freezer compartment 6 (S1). If cooling is not required, the process proceeds to step 2 and the compressor 30 is stopped (S2). If cooling is necessary, the process proceeds to step 3 to operate the compressor 30 to cool the room (S3). As a method for determining whether or not this cooling is necessary, the above-described transition conditions for the simultaneous cooling mode, the F cooling mode, and the R cooling mode, for example, when the room temperature of the refrigerator compartment 3 or the freezer compartment 6 is equal to or higher than the upper limit temperature respectively. Therefore, it is determined that cooling is necessary.

  In step 4, the flow rate adjusting device 22 is operated in consideration of the transition conditions for each cooling mode (S4). Specifically, for example, when the room temperature of the refrigerator compartment 3 and the freezer compartment 6 is equal to or higher than the upper limit temperature, the mode is switched to the simultaneous cooling mode so that the refrigerant flows through the R EVA 26 and the F EVA 24.

  When the compressor 30 is in operation, as described above, the refrigerant gas in the sealed case 31 is sucked from the first suction port 40a, so that the lubricating oil 60 and the refrigerant gas are discharged together. When the mixed gas flows out to the R-evapor 26 side, the intermediate pressure side suction pipe H is directly connected to the second compression portion 32b, so that the lubricating oil 60 does not flow out into the sealed case 31.

  At this time, since the lubricating oil 60 is sucked into the second compression part 32b, it is discharged again to the condenser side 21 together with the refrigerant gas and returned to the sealed case 31 if it flows out to the F EVA 24 side. However, since the restriction of the high temperature side capillary tube 25 is generally set to be looser than that of the low temperature side capillary tube 23, the refrigerant flows more easily on the R EVA 26 side, and the lubricating oil 60 mixed with the refrigerant is also on the R EVA 26 side. Therefore, it gradually accumulates in the piping such as the R-eva 26.

  That is, the longer the cooling operation for flowing the refrigerant through the R-eva 26, the less the lubricating oil 60 in the sealed case 31 decreases. For example, the lower end opening 34 c of the rotating shaft 14 that sucks the lubricating oil 60 is When the amount of the lubricating oil 60 is reduced to the position of the line, the lubricating oil 60 cannot be supplied to the compressing portion 32, so that the cylinders 35a and 35b and the pistons 36a and 36b are worn and the compressing portion 32 is broken. There is a fear.

  Therefore, in Step 5, the accumulated operation time of the compressor 30 in the simultaneous cooling mode or the R cooling mode is measured (S5), and in Step 6, whether the measured accumulated time has reached a predetermined time, here 1 hour or more. Whether or not is detected (S6).

  If the compressor 30 has been operated for a predetermined time or more, it is assumed that the lubricating oil 60 has accumulated in the R EVA 26 side piping and the lubricating oil 60 in the sealed case 31 has decreased. The mode is shifted to the F cooling mode (hereinafter referred to as a lubricant recovery mode) (S7). As a result, the flow rate adjusting device 22 only blocks or slightly flows the flow toward the R-eva 26 side, and therefore the lubricating oil 60 accumulated in the piping on the R-eva 26 side together with the refrigerant is added to the second compression portion 32b. Since the oil is recovered and discharged into the sealed case 31 through the piping on the F-eva 24 side, the lubricating oil 60 accumulated in the piping on the R-eva 26 side can be recovered.

  In step 8, it is detected whether or not this lubricant recovery mode has been operated for a predetermined time, here 10 minutes or more (S8), and if it has been operated for a predetermined time or longer, the lubricant 60 can be recovered. As a result, the process proceeds to step 9 to reset the accumulated operation time (S9), and the process returns to step 1 to repeat this control.

  In this case, in the lubricating oil recovery mode, the recovery of the lubricating oil 60 is given priority even when the room temperature of the refrigerator compartment 3 is equal to or higher than the upper limit temperature, but it does not adversely affect the cooling of the refrigerator compartment 3. It is preferable to set it for a short time (for example, 10 minutes). Also, when the refrigerator compartment 3 is below the upper limit temperature, the mode is not shifted to the simultaneous cooling mode or the like depending on the time, but is shifted to the simultaneous cooling mode or the R cooling mode as usual when the refrigerator chamber 3 reaches the upper limit temperature or more. You may let them. Further, the lubricant recovery mode is executed during the operation of the compressor 30. However, the operation of the compressor 30 does not have to be continuously performed. You may stop before executing the mode.

  According to this configuration, even if the lubricating oil 60 gradually accumulates in the piping of the R evaporator 26 and the amount of oil in the sealed case 31 of the compressor 30 decreases, the refrigerant that flows to the R evaporator 26 during the operation of the compressor 30. By cutting off or reducing the flow rate, the lubricating oil 60 accumulated in the piping on the R EVA 26 side is collected in the second compression section 32b and returned to the sealed case 31 via the piping on the F EVA 24 side. The oil amount of the oil 60 can be maintained, so that the compression portion 32 and the like can be prevented from being damaged.

  Next, another embodiment will be described. As shown in FIG. 5, this configuration is a configuration in which an oil amount detection device 70 that detects the amount of oil in the case is provided at the bottom of the sealed case 31. The oil amount detection device 70 only needs to be able to determine whether or not the oil amount has become equal to or less than a predetermined amount. For example, using an infrared sensor or the like, the oil amount detection device 70 can detect whether or not there is a predetermined amount of oil. Detection is made by utilizing the difference in reflection.

  In this case, in steps 5 and 6 described above, when the compressor 30 has been operated for a predetermined time or more, it was assumed that the amount of oil in the sealed case 31 has decreased. In addition, when the oil amount in the case falls below a predetermined amount, for example, the Z line or less, from the oil amount detection device 70, it is determined that oil cannot be supplied to the compression unit 32, and the F cooling mode is performed as in step 7. And the refrigerant collected in the R-eva 26 side piping is recovered.

  According to this configuration, since it is possible to directly detect a decrease in the lubrication amount 60 in the sealed case 31, it is possible to reliably prevent a problem that the oil cannot be supplied to the compression unit 32 or the like.

  The above-described flow rate adjusting device 22 has been described as a device that adjusts the flow rate to the F-evapor 24 and the R-eva 26. However, in the present invention, it is sufficient that the flow rate of the R-eva 26 can be cut off or reduced. As long as the flow rate of only the R-eva 26 is adjustable.

  The present invention can appropriately maintain the amount of lubricating oil, and can be applied to various refrigerators including a compressor having a two-stage compression mechanism.

It is a flowchart which shows the control method of this invention. It is a longitudinal cross-sectional view which shows the refrigerator of this invention. It is the schematic which shows the refrigerating cycle of a two-stage compression system. It is the cross-sectional view seen from the top which shows the compressor of a two-stage compression system. It is the longitudinal cross-sectional view seen from the front which shows the compressor of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Refrigerator main body 3 ... Refrigeration room 6 ... Freezer room 22 ... Flow control device 24 ... F EVA 26 ... R Eva 30 ... Compressor 31 ... Sealing case 32 ... Compression part 32a ... 1st compression part 32b ... 2nd compression part 60 ... Lubricating oil 70 ... Oil quantity detection device P ... Discharge pipe L ... Low pressure side suction pipe H ... Intermediate pressure side suction pipe

Claims (3)

A low-temperature evaporator and a high-temperature evaporator with different evaporation temperatures disposed in the refrigerator body, a flow rate adjusting device that is connected to at least the upstream side of the high-temperature evaporator and blocks the refrigerant flow to the high-temperature evaporator or changes the flow rate, and sealed A refrigeration cycle is formed from a first compression section and a second compression section provided in a case, and a two-stage compressor having an oil supply means for supplying lubricating oil to the first and second compression sections. The section compresses and discharges the refrigerant gas sucked into the sealed case from the low temperature evaporator side, and the second compression section includes the refrigerant gas sucked from the high temperature evaporator side and the refrigerant gas discharged from the first compression section. And the refrigerant flow through the high-temperature evaporator during operation of the two-stage compressor is shut off or reduced by the flow rate adjusting device to lubricate the high-temperature evaporator-side cycle piping. Oil two-stage compressor Refrigerator, characterized in that it was to be recovered. A normal operation mode in which a two-stage compressor is operated to allow refrigerant to flow through both the low-temperature evaporator and the high-temperature evaporator, and when the normal operation mode is operated for a predetermined time or more, a high temperature is generated during the operation of the two-stage compressor. A lubricating oil recovery mode for recovering the lubricating oil in the high-temperature evaporator-side cycle piping to a two-stage compressor by blocking or reducing the refrigerant flow flowing in the evaporator with the flow rate adjusting device. Item 10. The refrigerator according to Item 1. An oil level detection sensor for detecting the amount of lubricating oil is provided in the sealed case. When this oil level detection sensor detects that the oil level in the sealed case is less than or equal to the preset oil level, The refrigerant flow in the high-temperature evaporator during operation of the stage compressor is shut off or reduced by the flow rate adjusting device, whereby the lubricating oil in the cycle pipe on the high-temperature evaporator side is recovered in the two-stage compressor. The refrigerator according to claim 1.

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