JP2020180710A - Compression type refrigerator - Google Patents

Abstract

To provide a compression type refrigerator that can appropriately adjust a flow rate of refrigerant liquid without using a large-bore motor-operated valve.SOLUTION: A compression type refrigerator comprises a refrigerant flow rate adjustment device 20 for adjusting a flow rate of refrigerant liquid flowing through a refrigerant pipe 4C. The refrigerant flow rate adjustment device 20 comprises an upstream side orifice device 22 and a downstream side orifice device 23, a bypass line 26 branching from the refrigerant pipe 4C, and a flow rate control valve 28 attached to the bypass line 26. An outflow side end part 26b of the bypass line 26 is connected to the refrigerant pipe 4C at a position between the upstream side orifice device 22 and the downstream side orifice device 23. The bore of the bypass line 26 is smaller than the bore of the refrigerant pipe 4C.SELECTED DRAWING: Figure 1

Description

The present invention relates to a compression chiller provided with a compressor such as a turbo compressor or a screw compressor, and more particularly to a compression chiller configured to be capable of adjusting the flow rate of the refrigerant liquid.

The compression type refrigerator used for refrigeration and air conditioners is configured as a closed system in which a refrigerant is sealed. FIG. 7 is a schematic view showing a conventional compression type refrigerator. As shown in FIG. 7, the compression type refrigerator includes an evaporator 200 that removes heat from the fluid to be cooled and the refrigerant evaporates to exert a refrigerating effect, and a compressor that compresses the refrigerant gas evaporated by the evaporator 200. The 201, the condenser 202 that cools the compressed refrigerant gas with a cooling fluid and condenses it, and the expansion valve 203 that decompresses and expands the condensed refrigerant are connected by the refrigerant pipes 205A, 205B, 205C. It is configured.

In order to realize efficient operation of the compression refrigerator, it is important to appropriately control the opening degree of the expansion valve 203. That is, if the opening degree of the expansion valve 203 is too large, the refrigerant gas flows into the evaporator 200, that is, a so-called “blown-out” occurs, and the refrigerating efficiency (also referred to as the coefficient of performance (C.O.P)) is deteriorated. On the other hand, if the opening degree of the expansion valve 203 is too small, the refrigerant in the evaporator 200 is insufficient, which lowers the refrigerating output or causes the pressure in the evaporator 200 to drop. Therefore, high refrigeration efficiency can be achieved by appropriately controlling the opening degree of the expansion valve 203 according to the operating condition of the compression type refrigerator.

Japanese Unexamined Patent Publication No. 2011-38742 Japanese Unexamined Patent Publication No. 2011-2186

In the example shown in FIG. 7, an electric valve having the same diameter as that of the refrigerant pipe 205C is used for the expansion valve 203, and the opening degree of the expansion valve 203 is controlled according to the operating conditions such as the liquid level of the condenser 202. To. However, the large-diameter solenoid valve has a problem that the cost is high and the operating speed is slow, and as a result, the responsiveness of the flow rate control of the refrigerant liquid is poor.

As another method of flow rate control, as shown in FIG. 8, a configuration in which the fixed orifice 207 is provided in parallel with the motorized valve 203 is also implemented. However, in this configuration, it is necessary to select a fixed orifice 207 having a large opening. As a result, under operating conditions where the load is small and the flow rate of the refrigerant liquid is small, the passage of the refrigerant gas must be allowed to some extent, and it is difficult to improve the refrigerating efficiency.

Therefore, the present invention provides a compression type refrigerator capable of appropriately adjusting the flow rate of the refrigerant liquid without using a large-diameter motorized valve.

In one aspect, an evaporator that evaporates a refrigerant liquid to generate a refrigerant gas, a compressor that compresses the refrigerant gas, a condenser that condenses the compressed refrigerant gas to generate the refrigerant liquid, and the like. A refrigerant pipe extending between the condenser and the evaporator and a refrigerant flow rate adjusting device for adjusting the flow rate of the refrigerant liquid flowing through the refrigerant pipe are provided, and the refrigerant flow rate adjusting device is attached to the refrigerant pipe and in series. It is provided with an upstream side orifice device and a downstream side orifice device lined up in the above, a bypass line branching from the refrigerant pipe, and a flow control valve attached to the bypass line, and the inflow side end of the bypass line is the upstream side. It is connected to the refrigerant pipe at a position on the upstream side of the side orifice device, and the outflow side end of the bypass line is connected to the refrigerant pipe at a position between the upstream side orifice device and the downstream side orifice device. A compression type refrigerating machine is provided in which the diameter of the bypass line is smaller than the diameter of the refrigerant pipe.

The refrigerant liquid that has passed through the upstream orifice device is depressurized, and as a result, the refrigerant liquid that flows between the upstream orifice device and the downstream orifice device becomes low pressure. On the other hand, the refrigerant liquid flowing from the bypass line between the upstream orifice device and the downstream orifice device has a relatively high pressure because it is the refrigerant liquid before the pressure is reduced. Therefore, the refrigerant liquid flowing through the bypass line evaporates (flashes) momentarily when injected into the low-pressure refrigerant liquid, and generates bubbles composed of the refrigerant gas. The bubbles close the opening of the downstream orifice device and reduce the flow rate of the refrigerant liquid passing through the downstream orifice device. The flow rate of the refrigerant liquid changes depending on the amount of bubbles generated, and the amount of bubbles generated changes depending on the flow rate of the refrigerant liquid flowing through the bypass line. Therefore, the flow rate of the refrigerant liquid flowing through the refrigerant pipe can be controlled by adjusting the flow rate of the refrigerant liquid flowing through the bypass line with the flow rate control valve.

Since the flow rate of the refrigerant liquid flowing through the bypass line may be lower than the flow rate of the refrigerant liquid flowing through the refrigerant pipe, a pipe having a smaller diameter than the refrigerant pipe can be used for the bypass line. Therefore, a small and inexpensive flow control valve can be used as the flow control valve. Further, since the small flow rate control valve can quickly open and close the valve body, the flow rate of the refrigerant liquid can be quickly adjusted.

In one aspect, the compression refrigerating machine further comprises an economizer attached to the refrigerant piping, and the refrigerant flow rate adjusting device constitutes a first refrigerant flow rate adjusting device arranged on the upstream side of the economizer. The compression refrigerator further includes a second refrigerant flow rate adjusting device arranged on the downstream side of the economizer, and the second refrigerant flow rate adjusting device is a flow rate of the refrigerant liquid flowing from the economizer to the evaporator. Is configured to adjust.
According to the present invention, the flow rate of the refrigerant liquid flowing through the refrigerant pipe can be adjusted in two steps by the first refrigerant flow rate adjusting device and the second refrigerant flow rate adjusting device.

In one aspect, the second refrigerant flow control device includes a branch line branching from the bypass line, a second flow control valve attached to the branch line, and a second orifice device attached to the refrigerant pipe. The second orifice device is arranged between the economizer and the evaporator, and the outflow side end of the branch line is located at a position between the economizer and the second orifice device. It is connected to the.
In one aspect, the second refrigerant flow rate adjusting device has the same configuration as the first refrigerant flow rate adjusting device.

In one aspect, the bypass line has a refrigerant outlet located within the refrigerant pipe.
According to the present invention, bubbles composed of refrigerant gas quickly reach the opening of the downstream orifice device. Therefore, the response speed of the flow rate adjustment can be improved.
In one aspect, the refrigerant outlet is aligned with the opening of the downstream orifice device.

In one aspect, a subcooler is attached to the refrigerant pipe, the subcooler is located on the upstream side of the upstream orifice device, and the inflow side end of the bypass line is the sub. It is connected to the refrigerant pipe at a position on the upstream side of the cooler.

The subcooler can cool the refrigerant liquid sent from the condenser to the evaporator and supercool the refrigerant gas contained in the refrigerant liquid. Therefore, the subcooler can improve the refrigerating capacity of the evaporator. The bypass line is connected to the refrigerant pipe so as to guide the refrigerant liquid before being cooled by the subcooler between the upstream orifice device and the downstream orifice device. With such an arrangement, the relatively high-temperature refrigerant liquid flowing through the bypass line evaporates (flashes) momentarily when it flows into the refrigerant pipe, and the flow rate of the refrigerant liquid passing through the downstream orifice device is swiftly increased. Can be reduced to.

According to the present invention, a small and inexpensive flow control valve can be used as the flow control valve. Further, since the small flow rate control valve can quickly open and close the valve body, the flow rate of the refrigerant liquid can be quickly adjusted.

It is a schematic diagram which shows one Embodiment of a compression type refrigerator. It is an enlarged sectional view of the refrigerant flow rate adjusting device. It is a graph which shows the relationship between the flow rate of the refrigerant liquid introduced into the refrigerant pipe from a bypass line, and the flow rate of the refrigerant liquid which can pass through a downstream orifice device. It is a schematic diagram which shows the other embodiment of a compression type refrigerator. It is a schematic diagram which shows still another embodiment of a compression type refrigerator. It is a schematic diagram which shows still another embodiment of a compression type refrigerator. It is a schematic diagram which shows an example of the conventional turbo chiller. It is a schematic diagram which shows another example of the conventional turbo chiller.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an embodiment of a compression refrigerator. As shown in FIG. 1, the compression type refrigerator includes an evaporator 2 that evaporates the refrigerant liquid to generate the refrigerant gas, a compressor 1 that compresses the refrigerant gas, and a refrigerant liquid that condenses the compressed refrigerant gas. The condenser 3 is provided. The type of compressor 1 is not particularly limited. In one example, the compressor 1 is a centrifugal compressor (also referred to as a turbo compressor) or a screw compressor.

The suction port of the compressor 1 is connected to the evaporator 2 by the refrigerant pipe 4A. The discharge port of the compressor 1 is connected to the condenser 3 by the refrigerant pipe 4B. The condenser 3 is connected to the evaporator 2 by a refrigerant pipe 4C. The refrigerant pipe 4C is provided with a refrigerant flow rate adjusting device 20 for adjusting the flow rate of the refrigerant liquid flowing through the refrigerant pipe 4C.

The evaporator 2 takes heat from the fluid to be cooled (for example, cold water) and evaporates the refrigerant liquid to exert a freezing effect. The compressor 1 compresses the refrigerant gas evaporated by the evaporator 2, and the condenser 3 cools the compressed refrigerant gas with a cooling fluid (for example, cooling water) and condenses the refrigerant gas to generate a refrigerant liquid. The refrigerant liquid is depressurized by passing through the refrigerant flow rate adjusting device 20. The reduced pressure refrigerant liquid is sent to the evaporator 2. In this way, the compression refrigerator is configured as a closed system in which the refrigerant is sealed.

The refrigerant flow rate adjusting device 20 includes an upstream orifice device 22 and a downstream orifice device 23 attached to the refrigerant pipe 4C, a bypass line 26 branching from the refrigerant pipe 4C, and a flow rate control valve 28 attached to the bypass line 26. I have. The upstream orifice device 22 and the downstream orifice device 23 are arranged in series, and the upstream orifice device 22 is arranged upstream of the downstream orifice device 23 in the flow direction of the refrigerant liquid. Each of the upstream orifice device 22 and the downstream orifice device 23 is a fixed orifice device having an opening having a predetermined diameter, and does not have a function of stepwise changing the flow rate of the refrigerant liquid. The flow rate control valve 28 is composed of an electric valve, and has a function of stepwise changing the flow rate of the refrigerant liquid. The flow rate control valve 28 may be composed of a proportional solenoid valve or an electronic expansion valve instead of the electric valve.

The inflow side end portion 26a of the bypass line 26 is connected to the refrigerant pipe 4C at a position on the upstream side of the upstream orifice device 22. The outflow side end portion 26b of the bypass line 26 is connected to the refrigerant pipe 4C at a position between the upstream side orifice device 22 and the downstream side orifice device 23. A part of the refrigerant liquid flowing through the refrigerant pipe 4C flows into the bypass line 26 and is returned to the refrigerant pipe 4C through the bypass line 26. The diameter of the bypass line 26 is smaller than the diameter of the refrigerant pipe 4C, and the flow rate of the refrigerant liquid flowing through the bypass line 26 is lower than the flow rate of the refrigerant liquid flowing through the refrigerant pipe 4C.

The compression type refrigerator adjusts the opening degree of the flow rate control valve 28 based on the liquid level detector 34 that measures the liquid level of the refrigerant liquid in the condenser 3 and the liquid level that is measured by the liquid level detector 34. A valve control unit 37 for controlling is further provided. The valve control unit 37 is composed of at least one computer including a storage device in which the program is stored and an arithmetic unit that performs an operation according to an instruction included in the program. The liquid level detector 34 is electrically connected to the valve control unit 37, and the output signal of the liquid level detector 34 (that is, the measured value of the liquid level of the refrigerant liquid in the condenser 3) is the valve control unit 37. It is supposed to be sent to. The valve control unit 37 is configured to control the flow rate control valve 28 so that the liquid level of the refrigerant liquid in the condenser 3 is maintained within the set range.

The compression refrigerator further includes a pressure measuring device 40 for measuring the pressure in the evaporator 2. The pressure measuring device 40 is electrically connected to the valve control unit 37, and the output signal of the pressure measuring device 40 (that is, the measured value of the pressure in the evaporator 2) is sent to the valve control unit 37. There is. In one embodiment, the valve control unit 37 may control the flow control valve 28 so that the pressure in the evaporator 2 is maintained within the set range.

FIG. 2 is an enlarged cross-sectional view of the refrigerant flow rate adjusting device 20. The bypass line 26 has a refrigerant outlet 26c located in the refrigerant pipe 4C. The refrigerant outlet 26c is arranged close to the opening 23a of the downstream orifice device 23. The refrigerant liquid that has passed through the upstream orifice device 22 is depressurized, and as a result, the refrigerant liquid that flows between the upstream orifice device 22 and the downstream orifice device 23 is depressurized. On the other hand, the refrigerant liquid flowing from the bypass line 26 between the upstream orifice device 22 and the downstream orifice device 23 has a relatively high pressure because it is the refrigerant liquid before the pressure is reduced. Therefore, the refrigerant liquid flowing through the bypass line 26 momentarily evaporates (flashes) when injected into the low-pressure refrigerant liquid, and generates bubbles composed of the refrigerant gas. The bubbles close the opening 23a of the downstream orifice device 23 and reduce the flow rate of the refrigerant liquid passing through the downstream orifice device 23.

The flow rate of the refrigerant liquid passing through the downstream orifice device 23 changes depending on the amount of bubbles generated, and the amount of bubbles generated changes depending on the flow rate of the refrigerant liquid flowing through the bypass line 26. Therefore, by adjusting the flow rate of the refrigerant liquid flowing through the bypass line 26 with the flow rate control valve 28, the flow rate of the refrigerant liquid flowing through the refrigerant pipe 4C can be controlled.

Since the flow rate of the refrigerant liquid flowing through the bypass line 26 may be lower than the flow rate of the refrigerant liquid flowing through the refrigerant pipe 4C, a pipe having a smaller diameter than that of the refrigerant pipe 4C can be used for the bypass line 26. .. Therefore, a small and inexpensive flow rate control valve 28 can be used as the flow rate control valve 28. Further, since the small flow rate control valve 28 can quickly open and close the valve body, the flow rate of the refrigerant liquid can be quickly adjusted.

In the present embodiment, the refrigerant outlet 26c of the bypass line 26 is located in the refrigerant pipe 4C. More specifically, the refrigerant outlet 26c is aligned with the opening 23a of the downstream orifice device 23. According to such an arrangement, the bubbles composed of the refrigerant gas quickly reach the opening 23a of the downstream orifice device 23. Therefore, the response speed of the flow rate adjustment can be improved.

FIG. 3 is a graph showing the relationship between the flow rate of the refrigerant liquid introduced into the refrigerant pipe 4C from the bypass line 26 and the flow rate of the refrigerant liquid that can pass through the downstream orifice device 23. As shown in FIG. 3, the flow rate of the refrigerant liquid that can pass through the downstream orifice device 23 is substantially inversely proportional to the flow rate of the refrigerant liquid that is introduced from the bypass line 26 into the refrigerant pipe 4C. That is, when the flow rate of the refrigerant liquid introduced from the bypass line 26 into the refrigerant pipe 4C increases, the flow rate of the refrigerant liquid that can pass through the downstream orifice device 23 decreases.

The valve control unit 37 stores in advance a relational expression representing a graph as shown in FIG. The valve control unit 37 controls the opening degree of the flow rate control valve 28 based on the liquid level detected by the liquid level detector 34. Specifically, when the liquid level of the refrigerant liquid in the condenser 3 falls below the set range, the valve control unit 37 issues a command to the flow rate control valve 28 to increase the opening degree of the flow rate control valve 28. As a result, the flow rate of the refrigerant liquid that can pass through the downstream orifice device 23 decreases, and the liquid level of the refrigerant liquid in the condenser 3 rises. The relationship between the flow rate of the refrigerant liquid introduced into the refrigerant pipe 4C from the bypass line 26 and the flow rate of the refrigerant liquid that can pass through the downstream orifice device 23 as shown in FIG. 3 is determined by an experiment or a trial run. Can be obtained.

FIG. 4 is a schematic view showing another embodiment of the compression refrigerator. Since the configuration and operation of the present embodiment not particularly described are the same as those of the embodiment described with reference to FIGS. 1 and 2, the duplicate description thereof will be omitted. The compression refrigerator of the present embodiment includes a subcooler 45 attached to the refrigerant pipe 4C. The subcooler 45 is located on the upstream side of the upstream orifice device 22. The inflow side end portion 26a of the bypass line 26 is connected to the refrigerant pipe 4C at a position on the upstream side of the subcooler 45.

The subcooler 45 can cool the refrigerant liquid sent from the condenser 3 to the evaporator 2 and supercool the refrigerant gas contained in the refrigerant liquid. Therefore, the subcooler 45 can improve the refrigerating capacity of the evaporator 2. The bypass line 26 is connected to the refrigerant pipe 4C so as to guide the refrigerant liquid before being cooled by the subcooler 45 between the upstream orifice device 22 and the downstream orifice device 23. With such an arrangement, the relatively high-temperature refrigerant liquid flowing through the bypass line 26 momentarily evaporates (flashes) when flowing into the refrigerant pipe 4C, and the refrigerant liquid passing through the downstream orifice device 23 The flow rate can be reduced quickly.

FIG. 5 is a schematic view showing still another embodiment of the compression refrigerator. Since the configuration and operation of the present embodiment not particularly described are the same as those of the embodiment described with reference to FIGS. 1 and 2, the duplicate description thereof will be omitted. The compression refrigerator includes an economizer 9 arranged between the condenser 3 and the evaporator 2. The condenser 3 is connected to the economizer 9 by the refrigerant pipe 4C, and the economizer 9 is connected to the evaporator 2 by the refrigerant pipe 4D. Further, the economizer 9 is connected to the compressor 1 by the refrigerant pipe 4E. The economizer 9 is an intercooler arranged between the condenser 3 and the evaporator 2.

The refrigerant pipe 4C extending from the condenser 3 to the economizer 9 is provided with the first refrigerant flow rate adjusting device 20A, and the refrigerant pipe 4D extending from the economizer 9 to the economizer 2 is provided with the second refrigerant flow rate adjusting device 20B. In the present embodiment, the compressor 1 is composed of a multi-stage centrifugal compressor. More specifically, the compressor 1 is composed of a two-stage centrifugal compressor, and includes a first-stage impeller 11, a second-stage impeller 12, and an electric motor 13 for rotating these impellers 11, 12. There is.

A guide vane 16 for adjusting the suction flow rate of the refrigerant gas to the impellers 11 and 12 is arranged at the suction port of the compressor 1. The guide vane 16 is located on the suction side of the first stage impeller 11. The guide vanes 16 are arranged radially, and the opening degree of the guide vanes 16 is changed by rotating each guide vane 16 by a predetermined angle in synchronization with each other about its own axis. The refrigerant gas sent from the evaporator 2 passes through the guide vanes 16 and is then sequentially boosted by the rotating impellers 11 and 12. The boosted refrigerant gas is sent to the condenser 3 through the refrigerant pipe 4B.

The evaporator 2 takes heat from the fluid to be cooled (for example, cold water) and evaporates the refrigerant liquid to exert a freezing effect. The compressor 1 compresses the refrigerant gas evaporated by the evaporator 2, and the condenser 3 cools the compressed refrigerant gas with a cooling fluid (for example, cooling water) and condenses the refrigerant gas to generate a refrigerant liquid. The refrigerant liquid is depressurized by passing through the first refrigerant flow rate adjusting device 20A. The refrigerant gas existing in the depressurized refrigerant liquid is separated by the economizer 9 and sent to the intermediate suction port 17 provided between the first-stage impeller 11 and the second-stage impeller 12 of the compressor 1. The refrigerant liquid that has passed through the economizer 9 is depressurized by passing through the second refrigerant flow rate adjusting device 20B, and is further sent to the evaporator 2 through the refrigerant pipe 4D.

The first refrigerant flow rate adjusting device 20A is provided to adjust the flow rate of the refrigerant liquid flowing from the condenser 3 to the economizer 9. The first refrigerant flow rate adjusting device 20A has the same configuration as the refrigerant flow rate adjusting device 20 described with reference to FIGS. 1 and 2. That is, the first refrigerant flow rate adjusting device 20A is attached to the first upstream side orifice device 22 and the first downstream side orifice device 23 attached to the refrigerant pipe 4C, the bypass line 26 branching from the refrigerant pipe 4C, and the bypass line 26. It includes an attached first flow control valve 28. The elements corresponding to the elements of the embodiments described with reference to FIGS. 1 and 2 are numbered the same, and duplicate description thereof will be omitted.

The second refrigerant flow rate adjusting device 20B is provided to adjust the flow rate of the refrigerant liquid flowing from the economizer 9 to the evaporator 2. The second refrigerant flow rate adjusting device 20B includes a branch line 51 branching from the bypass line 26, a second flow rate control valve 52 attached to the branch line 51, and a second orifice device 55 attached to the refrigerant pipe 4D. ing. The second orifice device 55 is arranged between the economizer 9 and the evaporator 2.

The inflow side end 51a of the branch line 51 is connected to the bypass line 26, and the outflow side end 51b of the branch line 51 is connected to the refrigerant pipe 4D at a position between the economizer 9 and the second orifice device 55. .. Similar to the embodiment shown in FIG. 2, the branch line 51 has a refrigerant outlet (not shown) located in the refrigerant pipe 4D. The refrigerant outlet is arranged close to the opening of the second orifice device 55.

In the second refrigerant flow rate adjusting device 20B, the orifice device is not provided on the upstream side of the second orifice device 55. This is due to the following reasons. The refrigerant liquid that has reached the second orifice device 55 via the economizer 9 is depressurized when it passes through the first upstream orifice device 22 and the first downstream orifice device 23. On the other hand, the refrigerant liquid flowing through the branch line 51 has a relatively high pressure because it does not pass through the first upstream side orifice device 22 and the first downstream side orifice device 23. Therefore, the refrigerant liquid introduced into the refrigerant pipe 4D through the branch line 51 momentarily evaporates (flashes) in the presence of the low-pressure refrigerant liquid. As a result, the bubbles made of the refrigerant gas can block the second orifice device 55 and change the flow rate of the refrigerant liquid.

The compression refrigerator further includes a liquid level detector 57 for measuring the liquid level of the refrigerant liquid in the economizer 9. The liquid level detector 57 is electrically connected to the valve control unit 37, and the output signal of the liquid level detector 57 (that is, the measured value of the liquid level of the refrigerant liquid in the economizer 9) is sent to the valve control unit 37. It is supposed to be sent. The valve control unit 37 is configured to control the second flow rate control valve 52 so that the liquid level of the refrigerant liquid in the economizer 9 is maintained within the set range. In one embodiment, the valve control unit 37 may control the second flow control valve 52 so that the pressure in the evaporator 2 is maintained within the set range.

According to this embodiment, the flow rate of the refrigerant liquid flowing through the refrigerant pipes 4C and 4D can be adjusted in two steps by the first refrigerant flow rate adjusting device 20A and the second refrigerant flow rate adjusting device 20B. In one embodiment, the subcooler 45 shown in FIG. 4 may be arranged on the upstream side of the upstream orifice device 22. The installation position of the subcooler 45 is the same as that of the embodiment shown in FIG.

FIG. 6 is a schematic view showing still another embodiment of the compression refrigerator. Since the configuration and operation of the present embodiment not particularly described are the same as those of the embodiment described with reference to FIG. 5, the duplicated description will be omitted. In the present embodiment, the first refrigerant flow rate adjusting device 20A and the second refrigerant flow rate adjusting device 20B have the same configuration.

The first refrigerant flow rate adjusting device 20A includes a first upstream orifice device 22A and a first downstream orifice device 23A attached to the refrigerant pipe 4C, a first bypass line 26A branching from the refrigerant pipe 4C, and a first bypass line. It includes a first flow control valve 28A attached to 26A. The inflow side end portion 26a of the first bypass line 26A is connected to the refrigerant pipe 4C at a position on the upstream side of the first upstream side orifice device 22A. The outflow side end portion 26b of the first bypass line 26A is connected to the refrigerant pipe 4C at a position between the first upstream side orifice device 22A and the first downstream side orifice device 23A.

The second refrigerant flow rate adjusting device 20B includes a second upstream orifice device 22B and a second downstream orifice device 23B attached to the refrigerant pipe 4D, a second bypass line 26B branching from the refrigerant pipe 4D, and a second bypass line. It is provided with a second flow control valve 28B attached to 26B. The inflow side end portion 26d of the second bypass line 26B is connected to the refrigerant pipe 4D at a position on the upstream side of the second upstream side orifice device 22B. The outflow side end portion 26e of the second bypass line 26B is connected to the refrigerant pipe 4D at a position between the second upstream side orifice device 22B and the second downstream side orifice device 23B.

Since the configurations of the above elements of the first refrigerant flow rate adjusting device 20A and the second refrigerant flow rate adjusting device 20B are the same as those of the embodiments described with reference to FIGS. 1 and 2, the overlapping description thereof will be omitted.

Also in this embodiment, the flow rate of the refrigerant liquid flowing through the refrigerant pipes 4C and 4D can be adjusted in two steps by the first refrigerant flow rate adjusting device 20A and the second refrigerant flow rate adjusting device 20B. The embodiment shown in FIG. 6 is advantageous in that the length of the second bypass line 26B can be made shorter than the length of the branch line 51 of FIG. On the other hand, the embodiment shown in FIG. 5 is advantageous in that the second refrigerant flow rate adjusting device 20B has only a single second orifice device 55 and is therefore low in cost.

The above-described embodiment is described for the purpose of enabling a person having ordinary knowledge in the technical field to which the present invention belongs to carry out the present invention. Various modifications of the above embodiment can be naturally performed by those skilled in the art, and the technical idea of the present invention can be applied to other embodiments. Therefore, the present invention is not limited to the described embodiments, but is construed in the broadest range according to the technical idea defined by the claims.

1 Compressor 2 Evaporator 3 Condenser 4A, 4B, 4C, 4D, 4E Refrigerant piping 9 Economizer 11, 12 Impeller 13 Electric motor 16 Guide vane 17 Intermediate suction port 20 Refrigerator flow rate regulator 20A 1st refrigerant flow rate regulator 20B 2 Refrigerant flow rate adjusting device 22 Upstream orifice device 22A 1st upstream orifice device 22B 2nd upstream orifice device 23 Downstream orifice device 23A 1st downstream orifice device 23B 2nd downstream orifice device 26 Bypass line 26a Inflow side end Part 26b Outflow side end 26c Refrigerant outlet 26A 1st bypass line 26B 2nd bypass line 28 Flow control valve 28A 1st flow control valve 28B 2nd flow control valve 34 Liquid level detector 37 Valve control 40 Pressure measuring device 45 Sub Cooler 51 Branch line 52 Second flow control valve 55 Second orifice device 57 Liquid level detector

Claims (7)

An evaporator that evaporates the refrigerant liquid to generate refrigerant gas,
A compressor that compresses the refrigerant gas and
A condenser that condenses the compressed refrigerant gas to generate the refrigerant liquid, and
A refrigerant pipe extending between the condenser and the evaporator,
A refrigerant flow rate adjusting device for adjusting the flow rate of the refrigerant liquid flowing through the refrigerant pipe is provided.
The refrigerant flow rate adjusting device is
An upstream orifice device and a downstream orifice device attached to the refrigerant pipe and lined up in series,
A bypass line branching from the refrigerant pipe and
It is equipped with a flow control valve attached to the bypass line.
The inflow side end of the bypass line is connected to the refrigerant pipe at a position on the upstream side of the upstream orifice device.
The outflow side end of the bypass line is connected to the refrigerant pipe at a position between the upstream orifice device and the downstream orifice device.
A compression refrigerator in which the diameter of the bypass line is smaller than the diameter of the refrigerant pipe. The compression refrigerator further includes an economizer attached to the refrigerant pipe.
The refrigerant flow rate adjusting device constitutes a first refrigerant flow rate adjusting device arranged on the upstream side of the economizer.
The compression type refrigerator further includes a second refrigerant flow rate adjusting device arranged on the downstream side of the economizer, and the second refrigerant flow rate adjusting device measures the flow rate of the refrigerant liquid flowing from the economizer to the evaporator. The compression refrigerator according to claim 1, which is configured to be adjusted. The second refrigerant flow rate adjusting device is
A branch line that branches off from the bypass line and
The second flow control valve attached to the branch line and
It is equipped with a second orifice device attached to the refrigerant pipe.
The second orifice device is arranged between the economizer and the evaporator.
The compression refrigerator according to claim 2, wherein the outflow side end of the branch line is connected to the refrigerant pipe at a position between the economizer and the second orifice device. The compression refrigerator according to claim 2, wherein the second refrigerant flow rate adjusting device has the same configuration as the first refrigerant flow rate adjusting device. The compression refrigerator according to any one of claims 1 to 4, wherein the bypass line has a refrigerant outlet located in the refrigerant pipe. The compression refrigerator according to claim 5, wherein the refrigerant outlet is aligned with the opening of the downstream orifice device. A sub-cooler is attached to the refrigerant pipe.
The subcooler is located on the upstream side of the upstream orifice device.
The compression refrigerator according to claim 1, wherein the inflow side end of the bypass line is connected to the refrigerant pipe at a position on the upstream side of the subcooler.

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