JP2022032090A - Heat exchanger for refrigerator and refrigerator - Google Patents

Abstract

To provide a heat exchanger for a refrigerator which can suppress the reduction of a lubricant in a compressor and the lowering of heat-exchange performance caused by the reduction of a heat transmission area of a refrigerant in the heat exchanger, and the refrigerator.SOLUTION: A refrigerator 100 comprises: a heat exchanger body 11 which contains a first flow passage C1 allowing a first refrigerant to circulate from bottom to top and which causes a first refrigerant to evaporate by exchanging heat with a second refrigerant; a flow passage formation part 12 which is disposed in the heat exchanger body 11 and forms the first flow passage C1 in which the first refrigerant circulates; a second flow passage C3 which connects the heat exchanger body 11 and a first compressor 2 and allows the first refrigerant to circulate therein; and an oil sending mechanism including an oil sending pipe 13 which discharges the lubricant of the first compressor 2 for compressing the first refrigerant accumulated in the heat exchanger body 11 to the second flow passage C3 and which is connected to the lower part of the heat exchanger body 11.SELECTED DRAWING: Figure 2

Description

The present invention relates to a heat exchanger and a refrigerator for a refrigerator, and more particularly to a heat exchanger and a refrigerator for a refrigerator in which the first refrigerant evaporates by exchanging heat with a cooling target.

Conventionally, heat exchangers and refrigerators for refrigerators in which a refrigerant evaporates by exchanging heat with a cooling target are known (for example, Patent Document 1).

Patent Document 1 discloses a refrigerator including a compressor, a condenser, an evaporator, an expansion valve, and an oil separator.

In Patent Document 1, the refrigerant is compressed in a compressor and then condensed in a condenser. Then, the refrigerant condensed by the condenser becomes a gas-liquid two-phase state by the expansion valve and flows to the evaporator, and heat exchanges with the air to be cooled in the evaporator to take the heat of the air and evaporate. do. As a result, the air to be cooled is cooled. Further, in Patent Document 1, the oil separator is configured to separate the oil contained in the refrigerant leaving the compressor and return the separated oil to the compressor.

Here, although not disclosed in Patent Document 1, the refrigerant may flow in the vertical direction in the evaporator (heat exchanger). In addition, oil (lubricating oil) that cannot be completely separated by the oil separator may circulate together with the refrigerant. In this case, when the refrigerant flows from the bottom to the top, the refrigerant evaporates due to heat exchange, but the lubricating oil of the compressor does not evaporate and accumulates below the heat exchanger. As a result, the accumulation of lubricating oil in the heat exchanger causes a problem that the lubricating oil in the compressor is reduced and the heat exchange performance is deteriorated due to the reduction in the heat transfer area of the refrigerant in the heat exchanger. be.

Japanese Unexamined Patent Publication No. 2018-200135

The present invention has been made to solve the above-mentioned problems, and one object of the present invention is to reduce the lubricating oil in the compressor and the heat transfer area of the refrigerant in the heat exchanger. It is an object of the present invention to provide a heat exchanger for a refrigerator and a refrigerator capable of suppressing the occurrence of deterioration of heat exchange performance.

In order to achieve the above object, in the heat exchanger for a refrigerating machine according to the first aspect of the present invention, a first flow path through which the first refrigerant flows from the bottom to the top is provided inside, and the first refrigerant is a cooling target. A heat exchanger body that evaporates by exchanging heat with the heat exchanger, a flow path forming portion that is provided inside the heat exchanger body and forms a first flow path through which the first refrigerant flows, and a heat exchanger body and a compressor. In addition to connecting the above, the second flow path through which the first refrigerant flows and the lubricating oil of the compressor for compressing the first refrigerant accumulated in the heat exchanger body are discharged to the second flow path. It is equipped with an oil supply mechanism including an oil supply pipe connected to the lower part of the heat exchanger body.

In the heat exchanger for a refrigerator according to the first aspect of the present invention, as described above, the heat exchanger main body and the compressor are connected, the second flow path for circulating the first refrigerant, and the heat exchanger main body. A compressor lubricating oil for compressing the first refrigerant accumulated therein is discharged to the second flow path, and an oil feeding mechanism including an oil feeding pipe connected below the heat exchanger main body is provided. As a result, the lubricating oil accumulated in the heat exchanger main body is discharged to the second flow path, so that the lubricating oil does not collect in the heat exchanger main body and is returned to the compressor via the second flow path. As a result, it is possible to suppress a decrease in the lubricating oil in the compressor and a decrease in the heat exchange performance due to a decrease in the heat transfer area of the refrigerant in the heat exchanger body.

In the heat exchanger for a refrigerator according to the first aspect, preferably, the second flow path is configured to allow the first refrigerant to flow from the upper side to the lower side, and joins the oil supply pipe and the second flow path. The portion is arranged below the connection portion between the heat exchanger main body and the oil supply pipe. With this configuration, the confluence of the oil feed pipe and the second flow path is arranged below the connection portion between the heat exchanger body and the oil feed pipe, so that a pump for oil feed is not provided. However, since the lubricating oil flows from the upper side to the lower side in the oil supply pipe, the lubricating oil is discharged to the second flow path without accumulating in the oil supply pipe. Further, since the second flow path is configured to allow the first refrigerant to flow from the upper side to the lower side, the lubricating oil discharged to the second flow path also flows from the upper side to the lower side. Lubricating oil is returned to the compressor without accumulating in the second flow path.

The heat exchanger for a refrigerator according to the first aspect is preferably further provided with a heating mechanism for heating the lubricating oil in the oil supply pipe. With this configuration, the viscosity of the lubricating oil can be reduced by heating the lubricating oil in the oil feed pipe by the heating mechanism. As a result, by reducing the viscosity, the lubricating oil can be easily circulated in the oil feed pipe, so that the lubricating oil can be discharged to the second flow path more efficiently.

The heat exchanger for a refrigerator according to the first aspect is preferably further provided with an ejector mechanism provided at the confluence of the oil supply pipe and the second flow path and including a throttle portion for narrowing the width of the second flow path. .. With this configuration, negative pressure is generated by the acceleration of the first refrigerant when flowing through the second flow path whose width is narrowed by the throttle portion of the ejector mechanism. As a result, since the lubricating oil in the oil feeding pipe is sucked into the second flow path due to the negative pressure, the lubricating oil can be easily discharged to the second flow path without providing a pump for oil feeding.

In the heat exchanger for a refrigerator according to the first aspect, preferably, the flow path forming portion is a flat tube, and the first refrigerant flows between the outer peripheral surface of the flat tube and the inner surface of the heat exchanger body. , The second refrigerant to be cooled flows inside the flat tube, and the oil supply pipe discharges the lubricating oil accumulated between the outer peripheral surface of the flat tube and the inner surface of the heat exchanger body to the second flow path. It is configured in. With this configuration, the flat tube forms a flow path through which the first refrigerant flows and a flow path through which the second refrigerant flows. Therefore, the flow paths through which the first refrigerant and the second refrigerant flow are respectively. The number of parts of the heat exchanger for the refrigerator can be reduced as compared with the case where it is provided as a separate member.

In this case, it is preferable that the first refrigerant is provided between the inner surface of the heat exchanger main body and the outer peripheral surface of the flat tube, and the distance between the inner surface of the heat exchanger main body and the outer peripheral surface of the flat tube is set so that the first refrigerant is the outer peripheral surface of the flat tube. Further provided with spacers to set the flow interval along. With this configuration, the spacer sets the distance between the inner surface of the heat exchanger body and the outer peripheral surface of the flat tube to the interval at which the first refrigerant flows along the outer peripheral surface of the flat tube, so that the spacer keeps a constant interval. Since it is retained, it is possible to prevent the interval from becoming small. As a result, the amount of the first refrigerant flowing along the outer peripheral surface of the flat tube can be increased as compared with the case where the spacer is not provided, so that the amount of the first refrigerant that exchanges heat with the second refrigerant can be increased. Can be increased. As a result, the second refrigerant can be reliably cooled.

The refrigerator according to the second aspect is the heat exchanger for the refrigerator of the first aspect, the compressor that compresses the first refrigerant, the condenser that condenses the first refrigerant that has flowed through the compressor, and the condensation. It is provided between the container and the heat exchanger for the refrigerator and includes an expansion portion that lowers the pressure of the first refrigerant.

The refrigerator according to the second aspect is provided with a heat exchanger for the refrigerator according to the first aspect. As a result, the lubricating oil accumulated in the heat exchanger main body is discharged to the second flow path, so that the lubricating oil does not collect in the heat exchanger main body and is returned to the compressor via the second flow path. As a result, it is possible to suppress a decrease in the lubricating oil in the compressor and a decrease in the heat exchange performance due to a decrease in the heat transfer area of the refrigerant in the heat exchanger.

In the refrigerator according to the second aspect, preferably, a sensor for detecting the oil level in the compressor for compressing the first refrigerant, a valve provided in the oil supply pipe, and a drop in the oil level of the lubricating oil in the compressor are detected. Further, a control unit for controlling the valve to be opened so as to send lubricating oil from the heat exchanger main body to the second flow path through which the first refrigerant flows from the heat exchanger main body to the compressor is provided. With this configuration, the amount of lubricating oil in the compressor can be detected by providing a sensor that detects the oil level in the compressor that compresses the first refrigerant. Further, when the drop in the oil level of the lubricating oil in the compressor is detected, the valve is opened so as to send the lubricating oil from the heat exchanger body to the second flow path through which the first refrigerant flows from the heat exchanger body to the compressor. By providing a control unit for controlling the oil, the lubricating oil can be returned to the compressor via the second flow path when the amount of the lubricating oil in the compressor is small. As a result, it is possible to suppress the decrease of the lubricating oil in the compressor.

According to the present invention, it is possible to suppress the decrease in the lubricating oil in the compressor and the decrease in the heat exchange performance due to the decrease in the heat transfer area of the refrigerant in the heat exchanger as described above. It becomes possible to provide heat exchangers and refrigerators for refrigerators.

It is a block diagram which showed the structure of a dual refrigeration cycle. It is a figure which showed an example of an intermediate heat exchanger. It is sectional drawing which follows the AA line of FIG. It is a partially enlarged view of the flat tube for demonstrating the flow path formation part. It is a figure for demonstrating the 1st channel and the 2nd channel. It is a figure for demonstrating the flow of the refrigerant in a heat exchanger body. It is a figure for demonstrating the oil feeding mechanism in 1st Embodiment. It is a figure for demonstrating the oil feeding mechanism in 2nd Embodiment. It is a figure for demonstrating the oil feeding mechanism in 3rd Embodiment. It is a figure for demonstrating the ejector mechanism.

Hereinafter, embodiments embodying the present invention will be described with reference to the drawings.

[First Embodiment]
The configuration of the refrigerator 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 7. The refrigerator 100 is configured as a cooling / heating device for cooling (freezing / refrigerating) fresh foods and the like in the showcase 10.

As shown in FIG. 1, the refrigerator 100 includes two compression / expansion dual refrigeration cycles, in which the first refrigerant circulates in the first stage and the second refrigerant circulates in the second stage. The dual refrigeration cycle of the first embodiment includes an evaporator, a compressor, a condenser and an expansion part, and evaporates the first stage instead of the first stage evaporator and the second stage condenser. An intermediate heat exchanger 1 having both a vessel and a second-stage condenser is provided. The intermediate heat exchanger 1 is an example of a "heat exchanger for a refrigerator" within the scope of the claims. Further, the second refrigerant is an example of the "cooling target" in the claims.

In the first stage of the refrigeration cycle, the first refrigerant in the gas phase is compressed by the first compressor 2 to change into a high-temperature, high-pressure refrigerant. The first compressor 2 is, for example, a compressor, and compresses the gas phase refrigerant by the movement of the piston. At this time, lubricating oil is used to smooth the movement of the piston. Since a part of the lubricating oil is mixed with the compressed refrigerant, an oil separator is provided on the outlet side of the first compressor 2, and the lubricating oil mixed with the refrigerant is recovered by the oil separator and is collected by the first compressor 2. Returned to. Lubricating oil that cannot be recovered by the oil separator circulates in the refrigeration cycle together with the refrigerant.

The first refrigerant, which has become hot and high pressure in the first compressor 2, is supplied to the first condenser 3, exchanges heat with air or liquid, is cooled, and changes to a high-pressure liquid phase refrigerant. do. Then, the first refrigerant becomes a low-pressure low-temperature gas-liquid two-phase refrigerant when passing through the first expansion portion 4. Then, the first gas-liquid two-phase refrigerant is supplied to the intermediate heat exchanger 1. In the intermediate heat exchanger 1, the first refrigerant exchanges heat with the second refrigerant, and the gas-liquid two-phase changes to the gas phase. After that, the gas phase refrigerant is supplied to the first compressor 2.

In the second stage of the refrigeration cycle, the second refrigerant exchanges heat with the first refrigerant in the intermediate heat exchanger 1, and is condensed and changed to a high-pressure liquid phase refrigerant. Then, the second refrigerant becomes a low-pressure low-temperature gas-liquid two-phase refrigerant when passing through the second expansion portion 5. Then, the second refrigerant is supplied to the evaporator 6 and exchanges heat with the air or liquid to be cooled, and changes from the gas-liquid two-phase state to the gas phase. The refrigerant changed to the gas phase is supplied to the second compressor 7, and is compressed to change into a high-temperature, high-pressure liquid-phase refrigerant. The second refrigerant having a high temperature and high pressure in the second compressor 7 is supplied to the intermediate heat exchanger 1.

As shown in FIG. 2, the intermediate heat exchanger 1 has a cylindrical shape. In the intermediate heat exchanger 1, the first refrigerant flows from the lower side (Z2 side) to the upper side (Z1 side). Further, in the intermediate heat exchanger 1, the second refrigerant flows from the upper side (Z1 side) to the lower side (Z2 side).

As shown in FIG. 3, the intermediate heat exchanger 1 includes a heat exchanger main body 11, a flow path forming portion 12, an oil feeding mechanism (see FIG. 2) including an oil feeding pipe 13, and a spacer 14.

The heat exchanger body 11 has a cylindrical shape. The diameter of the heat exchanger body 11 is set to, for example, 160 mm or less. The heat exchanger main body 11 is a pressure-resistant container that can withstand the difference between the pressure of the low-pressure first refrigerant circulating inside and the pressure of the outside. The heat exchanger body 11 is made of, for example, metal.

A first flow path C1 (see FIG. 6) for flowing the first refrigerant and a third flow path C2 (see FIG. 6) for flowing the second refrigerant are formed inside the heat exchanger main body 11. To. Further, the heat exchanger main body 11 is configured to circulate the refrigerant from the heat exchanger main body 11 toward the first compressor 2 and to circulate the first refrigerant from the upper side to the lower side. Road C3 (see FIG. 7) is connected.

As shown in FIG. 4, the flow path forming portion 12 is composed of a plurality of flat tubes. The flat tubes are arranged in a cross shape in top view. The flat tube is provided with a plurality of protrusions 15 on the outer surface and has a plurality of microchannels 16 inside.

As shown in FIG. 5, the first flow path C1 is formed between the plurality of protrusions 15 and between the spacer 14 and the protrusions 15. Further, the third flow path C2 is formed by the microchannel 16. Further, since the protrusion 15 does not extend to the bottom surface side (Z2 side), the first refrigerant wraps around from the portion where the protrusion 15 is not provided, and the first refrigerant is supplied to all the first flow paths C1.

As shown in FIG. 6, the oil supply pipe 13 is connected to the lower side surface of the heat exchanger main body 11. The oil supply pipe 13 is brazed to the spacer 14 via an opening provided in the heat exchanger main body 11. The oil supply pipe 13 is a pipe for discharging the lubricating oil of the first compressor 2 accumulated in the heat exchanger main body 11 from the heat exchanger main body 11 to the second flow path C3.

As shown in FIG. 7, the confluence portion C4 between the oil feed pipe 13 and the second flow path C3 is arranged below the connection portion between the heat exchanger main body 11 and the oil feed pipe 13. The inner diameter and length of the oil feed pipe 13 differ depending on the operating state of the refrigeration cycle. For example, when the pressure in the heat exchanger main body 11 of the first fluid is 0.47 MPa and the flow rate is 134 g / s, the oil pressure is transferred to the third flow path C2 by setting the inner diameter of the oil feed pipe to 11.2 mm or more. It becomes higher than the internal pressure, and oil can be sent only by the pressure difference.

As shown in FIG. 6, a spacer 14 is provided inside the heat exchanger main body 11. The spacer 14 is arranged between the heat exchanger main body 11 and the flow path forming portion 12. A plurality of spacers 14 are provided, and are arranged so as to sandwich the flow path forming portion 12 from the X direction and the Y direction. The spacer 14 sets the distance between the inner surface of the heat exchanger main body 11 and the outer peripheral surface of the flow path forming portion 12 so that the first refrigerant flows along the outer peripheral surface of the flow path forming portion 12. The spacer 14 is provided with an opening for the first refrigerant to flow into the heat exchanger main body 11 or to flow out from the heat exchanger main body 11.

The heat exchanger main body 11 is provided with a first header 21 and a second header 22. The first header 21 is provided on the upper side of the heat exchanger main body 11, and the second refrigerant is supplied to the heat exchanger main body 11 via the first header 21. Inside the heat exchanger main body 11, a ring member 23 attached to the upper surface of the spacer 14 and a lid member 24 attached to the upper surface of the ring member 23 are provided. The lid member 24 partitions the space through which the first refrigerant flows and the space through which the second refrigerant flows. The lid member 24 is provided with a hole so as to connect to the microchannel 16 of the flat tube, and the second fluid flowing in from above is supplied to the microchannel 16 of the flat tube, respectively. The second header 22 is provided on the lower side of the heat exchanger main body 11, and the second refrigerant flows from the heat exchanger main body 11 to the evaporator 6 via the second header 22. A ring member 23 and a lid member 24 attached to the lower surface of the ring member 23 are also provided on the lower side of the heat exchanger main body 11. Therefore, the space through which the first refrigerant flows and the space through which the second refrigerant flows are partitioned by the lid member 24. Further, the lid member 24 is provided with a hole so as to be connected to the microchannel 16 of the flat tube, and the second refrigerant flowing in from above is collected and distributed to the evaporator 6.

The heat exchange between the first refrigerant and the second refrigerant will be described with reference to FIG. In FIG. 6, the flow of the first refrigerant is indicated by a solid arrow, and the flow of the second refrigerant is indicated by a broken line arrow. The first refrigerant flows into the inside from the inflow port 25 provided on the lower side surface of the heat exchanger main body 11. Then, it flows upward along the outer peripheral surface of the flow path forming portion 12 between the protrusions 15. Then, the high-temperature second refrigerant flowing in from above via the first header 21 flows inside the flow path forming portion 12, so that heat exchange is performed on the outer peripheral surface of the flow path forming portion 12, and the first. The refrigerant evaporates, and the first refrigerant is discharged to the second flow path C3 from the outlet 26 provided on the upper side surface of the heat exchanger main body 11. On the other hand, the second refrigerant is cooled and flows from the second header 22 to the evaporator 6. At this time, the lubricating oil remaining without evaporating accumulates on the lid member 24 provided on the lower side in the heat exchanger main body 11.

As shown in FIG. 7, the refrigerator 100 of the first embodiment further includes a sensor 8, a valve 17 provided in the oil supply pipe 13, and a control unit 9 for controlling the valve 17.

The sensor 8 is provided in the first compressor 2. The sensor 8 detects the height of the oil level of the lubricating oil in the first compressor 2. The sensor 8 detects the height of the oil level of the lubricating oil using, for example, light.

The valve 17 is, for example, a solenoid valve. By opening the valve 17, the lubricating oil accumulated in the heat exchanger main body 11 is discharged to the second flow path C3.

The control unit 9 is composed of, for example, a CPU (Central Processing Unit) and a memory. The control unit 9 controls to open the valve 17 when the height of the oil level detected by the sensor 8 is lower than a certain height. In the flow path between the first compressor 2 and the first condenser 3, there is an oil separator for recovering oil, and the oil recovered by the oil separator is returned to the first compressor 2, but the oil level is reached. The control unit 9 controls to open the valve 17 when the state where the height is below a certain height continues. Then, when the height of the oil level of the first compressor 2 recovers to a certain level or more, the control unit 9 controls to close the valve 17.

(Effect of the first embodiment)
In the first embodiment, the following effects can be obtained.

In the first embodiment, as described above, a first flow path C1 in which the first refrigerant flows from the bottom to the top is provided inside, and the first refrigerant evaporates by exchanging heat with the second refrigerant. The main body 11 and the flow path forming portion 12 provided inside the heat exchanger main body 11 and forming the first flow path C1 through which the first refrigerant flows, and the heat exchanger main body 11 and the first compressor 2 are connected to each other. At the same time, the lubricating oil of the second flow path C3 through which the first refrigerant flows and the lubricating oil of the first compressor 2 for compressing the first refrigerant accumulated in the heat exchanger main body 11 are discharged to the second flow path C3. In addition, an oil feeding mechanism including an oil feeding pipe 13 connected below the heat exchanger main body 11 is provided. As a result, the lubricating oil accumulated in the heat exchanger main body 11 is discharged to the second flow path C3, so that the lubricating oil does not collect in the heat exchanger main body 11 and is passed through the second flow path C3 to the first compressor. It is returned to 2. As a result, it is possible to suppress a decrease in the lubricating oil in the first compressor 2 and a decrease in the heat exchange performance due to a decrease in the heat transfer area of the refrigerant in the heat exchanger main body 11.

Further, in the first embodiment, as described above, the second flow path C3 is configured to allow the first refrigerant to flow from above to below, and is a confluence portion between the oil supply pipe 13 and the second flow path C3. C4 is arranged below the connection portion between the heat exchanger main body 11 and the oil supply pipe 13. As a result, the confluence portion C4 between the oil feed pipe 13 and the second flow path C3 is arranged below the connection portion between the heat exchanger main body 11 and the oil feed pipe 13, so that a pump for oil feed is provided. Even if the lubricating oil does not exist, the lubricating oil flows from the upper side to the lower side in the oil feeding pipe 13, so that the lubricating oil is discharged to the second flow path C3 without accumulating in the oil feeding pipe 13. Further, since the second flow path C3 is configured to allow the first refrigerant to flow from the upper side to the lower side, the lubricating oil discharged to the second flow path C3 also flows from the upper side to the lower side. Therefore, the lubricating oil is returned to the first compressor 2 without accumulating in the second flow path C3.

Further, in the first embodiment, as described above, the flow path forming portion 12 is a flat tube, and the first refrigerant flows between the outer peripheral surface of the flat tube and the inner surface of the heat exchanger main body 11 and is flat. The second refrigerant to be cooled flows through the inside of the pipe, and the oil supply pipe 13 discharges the lubricating oil accumulated between the outer peripheral surface of the flat pipe and the inner surface of the heat exchanger main body 11 to the second flow path C3. It is configured as follows. As a result, the flat pipe forms a flow path through which the first refrigerant flows and a flow path through which the second refrigerant flows. Therefore, the flow paths through which the first refrigerant and the second refrigerant flow are provided as separate members. The number of parts of the intermediate heat exchanger 1 can be reduced as compared with the case.

Further, in the first embodiment, as described above, the heat exchanger main body 11 is provided between the inner surface of the heat exchanger main body 11 and the outer peripheral surface of the flow path forming portion 12, and the inner surface of the heat exchanger main body 11 and the flow path forming portion 12 are provided. A spacer 14 is further provided for setting the distance from the outer peripheral surface so that the first refrigerant flows along the outer peripheral surface of the flow path forming portion 12. As a result, the spacer 14 sets the distance between the inner surface of the heat exchanger body 11 and the outer peripheral surface of the flat pipe to the distance at which the first refrigerant flows along the outer peripheral surface of the flat pipe, so that the spacer 14 maintains a constant distance. Therefore, it is possible to prevent the interval from becoming small. As a result, the amount of the first refrigerant flowing along the outer peripheral surface of the flat tube can be increased as compared with the case where the spacer 14 is not provided, so that the amount of the first refrigerant that exchanges heat with the second refrigerant is performed. Can be increased. As a result, the second refrigerant can be reliably cooled.

Further, in the first embodiment, as described above, the sensor 8 that detects the oil level in the first compressor 2 that compresses the first refrigerant, the valve 17 provided in the oil feed pipe 13, and the first compressor 2 When the drop in the oil level of the lubricating oil inside is detected, the valve 17 is directed to send the lubricating oil from the heat exchanger main body 11 to the second flow path C3 through which the first refrigerant flows from the first compressor body 2. Further includes a control unit 9 for controlling the open state. Thereby, by providing the sensor 8 for detecting the oil level in the first compressor 2 for compressing the first refrigerant, the amount of the lubricating oil in the first compressor 2 can be detected. Further, when the drop in the oil level of the lubricating oil in the first compressor 2 is detected, the lubricating oil is supplied from the heat exchanger main body 11 to the second flow path C3 through which the first refrigerant flows from the first compressor 2 to the first compressor 2. By providing a control unit 9 that controls the valve 17 to be in an open state so as to supply oil, the lubricating oil is returned to the first compressor 2 when the amount of the lubricating oil in the first compressor 2 is small. Can be done. As a result, it is possible to suppress the decrease of the lubricating oil in the first compressor.

[Second Embodiment]
A second embodiment will be described with reference to FIGS. 1 and 8. In the refrigerator 200 of the second embodiment, the heating mechanism 18 is provided in the oil supply pipe 13. The same configurations as those of the first embodiment are shown with the same reference numerals in the drawings, and the description thereof will be omitted.

As shown in FIG. 8, the intermediate heat exchanger 1 according to the second embodiment is provided with a heating mechanism 18 for heating the lubricating oil in the oil supply pipe 13. The heating mechanism 18 is, for example, a heater. The control unit 9 operates the heating mechanism 18 to heat the lubricating oil in the oil supply pipe 13 when controlling to open the valve 17. Since the heating mechanism 18 causes a pressure difference for oil feeding, it is preferable to provide the heating mechanism 18 in the vicinity of the joint portion between the heat exchanger main body 11 and the oil feeding pipe 13. Further, the number of the heating mechanisms 18 may be 1 or more, but it is preferable that the number of the heating mechanisms 18 is small so as not to affect the temperature of the first refrigerant.

Other configurations of the second embodiment are the same as those of the first embodiment.

(Effect of the second embodiment)
In the second embodiment, as in the first embodiment, the refrigerator 200 is provided with a first flow path C1 in which the first refrigerant flows from the bottom to the top, and the first refrigerant heats with the second refrigerant. A heat exchanger main body 11 that evaporates by exchanging, a flow path forming portion 12 provided inside the heat exchanger main body 11 and forming a first flow path C1 through which the first refrigerant flows, and a heat exchanger main body 11 2 and the second flow path C3 through which the first refrigerant flows, and the lubrication of the first compressor 2 for compressing the first refrigerant accumulated in the heat exchanger main body 11 while connecting the first compressor 2 and the second flow path C3. It is provided with an oil feeding mechanism including an oil feeding pipe 13 connected below the heat exchanger main body 11 while discharging the oil to the second flow path C3. As a result, the lubricating oil accumulated in the heat exchanger main body 11 is discharged to the second flow path C3, so that the lubricating oil does not collect in the heat exchanger main body 11 and is passed through the second flow path C3 to the first compressor. It is returned to 2. As a result, it is possible to suppress a decrease in the lubricating oil in the first compressor 2 and a decrease in the heat exchange performance due to a decrease in the heat transfer area of the refrigerant in the heat exchanger main body 11.

Further, in the second embodiment, as described above, the heating mechanism 18 for heating the lubricating oil in the oil feed pipe 13 is further provided. As a result, the heating mechanism 18 heats the lubricating oil in the oil feeding pipe 13, so that the viscosity of the lubricating oil can be reduced. As a result, by reducing the viscosity, the lubricating oil can easily flow through the oil feed pipe 13, so that the lubricating oil can be more efficiently discharged to the second flow path C3.

The other effects of the second embodiment are the same as those of the first embodiment.

[Third Embodiment]
A third embodiment will be described with reference to FIGS. 1, 9 and 10. In the refrigerator 300 according to the third embodiment, the ejector mechanism 19 is provided at the confluence portion C4 between the oil supply pipe 13 and the second flow path C3. The same configurations as those of the first embodiment are shown with the same reference numerals in the drawings, and the description thereof will be omitted.

As shown in FIG. 9, an ejector mechanism 19 is provided at the confluence portion C4 between the oil supply pipe 13 and the second flow path C3. As shown in FIG. 10, the ejector mechanism 19 includes a throttle portion 27 that narrows the width of the second flow path C3. In the ejector mechanism 19, the first refrigerant accelerates as it passes through the throttle portion 27, and when the first refrigerant accelerates, a negative pressure is generated and the lubricating oil is sucked. The sucked lubricating oil flows to the first compressor 2.

The other configurations of the third embodiment are the same as those of the first embodiment.

(Effect of the third embodiment)
In the third embodiment, the following effects can be obtained.

In the third embodiment, as in the first embodiment, the refrigerator 300 is provided with a first flow path C1 in which the first refrigerant flows from the bottom to the top, and the first refrigerant heats with the second refrigerant. A heat exchanger main body 11 that evaporates by exchanging, a flow path forming portion 12 provided inside the heat exchanger main body 11 and forming a first flow path C1 through which the first refrigerant flows, and a heat exchanger main body 11 2 and the second flow path C3 through which the first refrigerant flows, and the lubrication of the first compressor 2 for compressing the first refrigerant accumulated in the heat exchanger main body 11 while connecting the first compressor 2 and the second flow path C3. It is provided with an oil feeding mechanism including an oil feeding pipe 13 connected below the heat exchanger main body 11 while discharging the oil to the second flow path C3. As a result, the lubricating oil accumulated in the heat exchanger main body 11 is discharged to the second flow path C3, so that the lubricating oil does not collect in the heat exchanger main body 11 and is passed through the second flow path C3 to the first compressor. It is returned to 2. As a result, it is possible to suppress a decrease in the lubricating oil in the first compressor 2 and a decrease in the heat exchange performance due to a decrease in the heat transfer area of the refrigerant in the heat exchanger main body 11.

Further, in the third embodiment, as described above, the ejector mechanism 19 provided at the confluence portion C4 between the oil supply pipe 13 and the second flow path C3 and includes the throttle portion 27 for narrowing the width of the second flow path C3 is provided. Further prepare. As a result, a negative pressure is generated by accelerating the first refrigerant when flowing through the second flow path C3 whose width is narrowed by the throttle portion 27 of the ejector mechanism 19. As a result, since the lubricating oil in the oil feeding pipe 13 is sucked into the second flow path C3 due to the negative pressure, the lubricating oil can be easily discharged to the second flow path C3 without providing a pump for oil feeding. Can be done.

The other effects of the third embodiment are the same as those of the first embodiment.

(Modification example)
It should be noted that the embodiments disclosed this time are exemplary in all respects and are not considered to be restrictive. The scope of the present invention is shown by the scope of claims rather than the description of the above-described embodiment, and further includes all modifications (modifications) within the meaning and scope equivalent to the scope of claims.

For example, in the first to third embodiments, the heat exchanger for a refrigerator is used for a two-way refrigeration cycle, but the present invention is not limited to this. For example, the heat exchanger for the refrigerator may be used as an evaporator for a refrigeration cycle of only one system. In this case, the cooling target may be air or liquid.

Further, in the first to third embodiments, the example in which the flow path forming portion is a flat tube is shown, but the present invention is not limited to this. For example, the flow path forming portion may be a cylindrical tube.

Further, in the first to third embodiments, the example in which the oil feed pipe is connected to the lower side surface of the heat exchanger main body is shown, but the present invention is not limited to this. For example, the oil feed pipe may be connected to the side surface of the central portion of the heat exchanger body.

Further, in the first to third embodiments, the second flow path shows an example in which the first refrigerant flows from the upper side to the lower side, but the present invention is not limited to this. If P1> P2 is established between the pressure at the inlet of the oil supply pipe (P1) and the pressure at the confluence (P2), taking into consideration the density of the first refrigerant and lubricating oil and the influence of gravity, the second flow path and The configuration (direction and connection position) of the oil supply pipe is not particularly limited.

Further, in the first to third embodiments, the control unit shows an example of controlling the valve to be opened when the sensor detects a drop in the oil level of the first compressor. Not limited to this. In the present invention, the control unit may open and close the valve at regular intervals to periodically control the oil supply to the second flow path.

Further, in the first to third embodiments, the control unit shows an example of controlling the valve to be opened when the sensor detects a drop in the oil level of the first compressor. Not limited to this. In the present invention, the control unit detects, for example, a decrease in the amount of heat exchange by measuring the heat flux in the heat exchanger body, or a insufficient phase change of the refrigerant by measuring the pressure in the second flow path on the compressor side. May be controlled to open the state.

Further, the third embodiment shows an example in which an ejector mechanism is provided in addition to the configuration of the first embodiment, but the present invention is not limited to this. In the present invention, the third embodiment may be configured to provide an ejector mechanism in addition to the configuration of the second embodiment.

1 Intermediate heat exchanger 2 First compressor (compressor)
4 1st expansion part 8 Sensor 9 Control part 11 Heat exchanger body 12 Flow path forming part 13 Oil supply pipe 14 Spacer 17 Valve 18 Heating mechanism 19 Ejector mechanism 27 Squeezing part 100, 200, 300 Refrigerator C1 1st flow path C2 1st 3 flow path C3 2nd flow path C4 confluence

Claims (8)

A first flow path through which the first refrigerant flows from the bottom to the top is provided inside, and the heat exchanger body evaporates when the first refrigerant exchanges heat with the cooling target.
A flow path forming portion provided inside the heat exchanger body and forming the first flow path through which the first refrigerant flows, and a flow path forming portion.
A second flow path that connects the heat exchanger main body and the compressor and distributes the first refrigerant, and
The lubricating oil of the compressor for compressing the first refrigerant accumulated in the heat exchanger main body is discharged to the second flow path, and the oil supply pipe connected to the lower part of the heat exchanger main body is provided. A heat exchanger for a refrigerator, including an oil feeding mechanism. The second flow path is configured to allow the first refrigerant to flow from above to below.
The heat exchanger for a refrigerator according to claim 1, wherein the confluence portion between the oil supply pipe and the second flow path is arranged below the connection portion between the heat exchanger main body and the oil supply pipe. The heat exchanger for a refrigerator according to claim 1 or 2, further comprising a heating mechanism for heating the lubricating oil in the oil feed pipe. The invention according to any one of claims 1 to 3, further comprising an ejector mechanism provided at a confluence of the oil supply pipe and the second flow path and including a throttle portion for narrowing the width of the second flow path. Heat exchanger for refrigerators. The flow path forming portion is a flat tube and is
The first refrigerant flows between the outer peripheral surface of the flat tube and the inner surface of the heat exchanger body, and the second refrigerant to be cooled flows inside the flat tube.
The oil feeding pipe is configured to discharge the lubricating oil accumulated between the outer peripheral surface of the flat pipe and the inner surface of the heat exchanger body to the second flow path, according to claims 1 to 4. The heat exchanger for a refrigerator according to any one of the items. The first refrigerant is provided between the inner surface of the heat exchanger body and the outer peripheral surface of the flat tube, and the distance between the inner surface of the heat exchanger body and the outer peripheral surface of the flat tube is set so that the first refrigerant is the outer peripheral surface of the flat tube. The heat exchanger for a refrigerator according to claim 5, further comprising a spacer for setting a flow interval along the line. The heat exchanger for a refrigerator according to any one of claims 1 to 6, the compressor for compressing the first refrigerant, and a condenser for condensing the first refrigerant distributed through the compressor. A refrigerator provided between the condenser and the heat exchanger for the refrigerator and having an expansion portion for reducing the pressure of the first refrigerant. A sensor that detects the oil level in the compressor that compresses the first refrigerant, and
The valve provided in the oil supply pipe and
When the drop in the oil level of the lubricating oil in the compressor is detected, the lubricating oil is sent from the heat exchanger main body to the second flow path through which the first refrigerant flows toward the compressor. The refrigerator according to claim 7, further comprising a control unit for controlling the valve in an open state.

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