JP2020038039A - Double tube flooded evaporator and ice maker - Google Patents

Abstract

To provide a double tube flooded evaporator that can downsize or omit an accumulator.SOLUTION: A double tube flooded evaporator comprises an outer tube, and an inner tube provided in the outer tube, passes a medium to be cooled through the inner tube, and passes a refrigerant through a space between the inner tube and the outer tube. The flooded evaporator is a horizontal type in which each axis of the outer tube and the inner tube is horizontal. A refrigerant path from a refrigerant supply port formed in a lower part of the outer tube to a refrigerant discharge port formed in an upper part of the outer tube is composed of the space. The refrigerant path comprises a refrigerant path enlargement part in which a width of the space becomes larger in a direction toward the refrigerant discharge port, in a cross section perpendicular to an axial direction of the inner tube.SELECTED DRAWING: Figure 4

Description

  The present disclosure relates to a double-pipe liquid-filled evaporator and an ice maker. More specifically, the present invention relates to a double-tube full-fill evaporator and an ice maker in an ice maker for producing a sherbet-shaped ice slurry.

  Patent Literature 1 discloses an ice making refrigeration apparatus including a double-pipe liquid-filled evaporator having an inner pipe through which a medium to be cooled flows, and an outer pipe containing the inner pipe. This ice making refrigeration system expands a high-pressure liquid refrigerant flowing out of a condenser by an expansion mechanism to reduce the pressure, and supplies the low-pressure liquid refrigerant to an outer cooling chamber between an inner pipe and an outer pipe of a liquid-filled evaporator. . Thereby, the medium to be cooled flowing through the inner pipe is cooled, while the liquid refrigerant in the outer cooling chamber evaporates. The medium to be cooled in the inner tube is turned into slurry ice by releasing the supercooling by the rotating blade. The low-pressure refrigerant evaporated in the outer cooling chamber is discharged from the liquid-filled evaporator and returned to the suction side of the compressor.

JP 2003-185285 A

  In the conventional liquid-filled evaporator including the liquid-filled evaporator described in Patent Document 1, it is necessary to discharge the refrigerant in the two-phase state from the liquid-filled evaporator in order to return the refrigerating machine oil to the compressor. However, in a liquid-filled evaporator, forming (a phenomenon in which the liquid refrigerant is rapidly gasified) becomes more likely to occur as the evaporation proceeds, and the flow velocity of the refrigerant increases rapidly when this forming occurs. There is a possibility that a lot of refrigerant in a liquid state flows to the compressor side. When a refrigerant containing a large amount of liquid enters the compressor, a sudden high pressure (liquid compression) or a decrease in viscosity of the refrigerating machine oil causes a failure of the compressor. Therefore, in order to avoid such inconvenience, it is necessary to install an accumulator (gas-liquid separator) at the inlet of the compressor in a conventional ice making system including a liquid-filled evaporator.

  However, accumulators are expensive, and measures are desired to reduce the cost of the device.

  An object of the present disclosure is to provide a double-tube type liquid-filled evaporator and an ice maker that can realize the miniaturization or omission of an accumulator.

The double-tube type liquid-filled evaporator of the present disclosure (hereinafter, also simply referred to as “liquid-filled evaporator”) is
(1) A double pipe type having an outer pipe and an inner pipe provided in the outer pipe, in which a medium to be cooled flows in the inner pipe, and a refrigerant flows in a space between the inner pipe and the outer pipe. Liquid evaporator,
The liquid-filled evaporator includes:
Each of the outer pipe and the inner pipe is a horizontal type in which each axis is horizontal,
The space constitutes a refrigerant path from a refrigerant supply port formed at a lower portion of the outer tube to a refrigerant discharge port formed at an upper portion of the outer tube,
The path of the refrigerant has a refrigerant path enlarging portion in which a width of the space increases in a direction toward the refrigerant discharge port in a cross section perpendicular to the axial direction of the inner pipe.

  In the liquid-filled evaporator of the present disclosure, the path of the refrigerant formed of the space between the inner tube and the outer tube has a cross section perpendicular to the axial direction of the inner tube, and the space of the space extends in a direction toward the refrigerant outlet. It has a refrigerant path enlarging portion whose width is increased. By providing such a refrigerant path enlarging section, even if the forming occurs when the refrigerant moves from the refrigerant supply port to the refrigerant discharge port, the refrigerant path enlarging section has a capacity on the outlet side of the refrigerant path enlarging section. Since the volume is larger than the volume on the inlet side, it is possible to suppress an increase in the flow velocity of the refrigerant due to the forming. As a result, the liquid refrigerant can be prevented from being discharged from the refrigerant discharge port, and the accumulator provided on the inlet side of the compressor can be reduced in size or omitted.

  (2) In the liquid-filled evaporator according to the above (1), the outer tube and the inner tube have a cylindrical shape, and the outer tube and the inner tube are arranged such that one axis is in a vertical direction with respect to the other axis. It can be arranged to be eccentric. In this case, the width of the space at the end point side end of the refrigerant path can be made larger than the space width at the start point side end of the path by simply shifting the axis of the inner pipe and the outer pipe in the vertical direction. In addition, it is possible to easily provide the refrigerant path enlarging portion.

(3) In the liquid-filled evaporator of (2), the inner diameter of the outer tube is Do, the outer diameter of the inner tube is Di, and the vertical distance between the axis of the outer tube and the axis of the inner tube. Is G, L = (Do−Di) / 2, it is desirable that the distance G is not less than 0.42 L and not more than 0.74 L. In this case, the width of the space at the end point side end of the path of the refrigerant can be made larger than the width of the space at the start point side end of the path without excessively increasing the pressure loss due to the flow of the refrigerant.

(4) In the liquid-filled evaporator according to any one of (1) to (3), the width of the space in the refrigerant path expanding section is gradually and continuously increased from the inlet side to the outlet side of the refrigerant path expanding section. It is desirable to be done. In this case, by gradually increasing the width of the space, it is possible to suppress an increase in pressure loss due to the flow of the refrigerant as compared with a case where the width is discontinuously or rapidly increased.

(5) The ice making machine of the present disclosure includes the double-tube type liquid-filled evaporator according to any one of (1) to (4).

1 is a schematic configuration diagram of an ice making system including an ice maker including a liquid-filled evaporator according to an embodiment of the present disclosure. FIG. 2 is an explanatory side view of the ice making machine shown in FIG. 1. FIG. 3 is an explanatory sectional view of a blade mechanism in the ice making machine shown in FIG. 2. It is a cross-sectional explanatory view of a liquid-filled evaporator, (a) shows the conventional liquid-filled evaporator in which the axes of the outer tube and the inner tube are coincident, and (b) is shown in FIG. 1 shows a liquid-filled evaporator in an ice making machine. It is explanatory drawing which shows the eccentricity of an inner tube and an outer tube. It is a graph which shows the relationship between the eccentric distance and the clearance of the inner and outer pipes. FIG. 6 is an explanatory cross-sectional view of a liquid evaporator according to another embodiment of the present disclosure. It is a cross-sectional explanatory view of another example of the ice making system provided with the ice making machine including the liquid evaporator of the present disclosure.

  Hereinafter, the liquid-filled evaporator and the ice maker of the present disclosure will be described in detail with reference to the accompanying drawings. Note that the present disclosure is not limited to these exemplifications, but is indicated by the claims, and is intended to include all modifications within the scope and meaning equivalent to the claims.

  FIG. 1 is a schematic configuration diagram of an ice making system A including an ice maker 1 including a liquid-filled evaporator according to an embodiment of the present disclosure, and FIG. 2 is a side view of the ice maker 1 shown in FIG. FIG. The ice making system A is a system in which ice slurry is continuously generated by the ice maker 1 using seawater stored in a seawater tank described later as a raw material, and the generated ice slurry is returned to the seawater tank. The ice slurry refers to sherbet-like ice in which fine ice is turbid in water or an aqueous solution, and is also referred to as slurry ice, ice slurry, slurry ice, sluff ice, and liquid ice. The ice making system A can continuously generate an ice slurry based on seawater. For this reason, the ice making system A is installed in, for example, a fishing boat or fishing port, and the ice slurry returned to the seawater tank is used for keeping fresh fish cool.

  The ice making system A uses seawater as a medium to be cooled, and in addition to the ice making machine 1 constituting the use side heat exchanger, a compressor 2, a heat source side heat exchanger 3, a four-way switching valve 4, a use side expansion valve 5, a heat source A side expansion valve 6, an accumulator 7, a receiver 8, a seawater tank (storage tank) 9, and a pump 10 are provided. The ice maker 1, the compressor 2, the heat source side heat exchanger 3, the four-way switching valve 4, the use side expansion valve 5, the heat source side expansion valve 6, the accumulator 7, and the receiver 8 constitute a refrigerating device, and these devices or The members are connected by piping to form a refrigerant circuit. The ice maker 1, the seawater tank 9, and the pump 10 are also connected by piping to form a seawater circulation path.

  During a normal ice making operation, the four-way switching valve 4 is maintained in a state shown by a solid line in FIG. The high-temperature and high-pressure gaseous refrigerant discharged from the compressor 2 flows into the heat source side heat exchanger 3 functioning as a condenser via the four-way switching valve 4, and exchanges heat with air by the operation of the blower fan 11 to condense and condense. Liquefy. The liquefied refrigerant flows into the use-side expansion valve 5 via the heat-source-side expansion valve 6 and the receiver 8 in the fully opened state. The refrigerant is decompressed to a predetermined low pressure by the use-side expansion valve 5 and supplied from a refrigerant inlet pipe, which will be described later, into the annular space 14 between the inner pipe 12 and the outer pipe 13 constituting the evaporator E of the ice making machine 1. Is done.

  The refrigerant jetted into the annular space 14 exchanges heat with seawater flowing into the inner pipe 12 by the pump 10 and evaporates. The seawater cooled by the evaporation of the refrigerant flows out of the inner pipe 12 and returns to the seawater tank 8. The refrigerant evaporated and vaporized in the ice making machine 1 is sucked into the compressor 2. At that time, when the refrigerant containing liquid without being completely evaporated by the ice making machine 1 enters the compressor 2, the compressor 2 fails due to a sudden increase in the pressure inside the compressor cylinder (liquid compression) and a decrease in the viscosity of the refrigerating machine oil. Therefore, an accumulator 7 is provided on the suction side of the compressor 2 to protect the compressor 2, and the refrigerant flowing into the accumulator 7 via the four-way switching valve 4 is charged by the accumulator 7. , And is separated into a gaseous refrigerant and a liquid refrigerant, and the gaseous refrigerant returns to the compressor 2. The accumulator 7 is downsized compared to the case where a conventional evaporator is employed, due to the features and configuration of the evaporator E described later.

  In addition, when the flow of seawater in the inner pipe 12 of the ice maker 1 is interrupted and ice is accumulated in the inner pipe 12 (ice accumulation), the ice maker 1 cannot be operated. In this case, a defrost operation (heating operation) is performed to melt the ice in the inner pipe 12. At this time, the four-way switching valve 4 is maintained in the state shown by the broken line in FIG. The high-temperature and high-pressure gaseous refrigerant discharged from the compressor 2 flows into the annular space 14 between the inner pipe 12 and the outer pipe 13 of the ice making machine 1 via the four-way switching valve 4, and the ice in the inner pipe 12. Condensed and liquefied by heat exchange with seawater containing. The liquefied refrigerant flows into the heat-source-side expansion valve 6 via the use-side expansion valve 5 and the receiver 8 in the fully-open state, and is depressurized to a predetermined low pressure by the heat-source-side expansion valve 6, so that the heat-source-side heat exchange functioning as an evaporator is performed. It flows into the vessel 3. During the defrost operation, the refrigerant flowing into the heat source side heat exchanger 3 functioning as an evaporator exchanges heat with air by the operation of the blower fan 11, is vaporized, and is sucked into the compressor 2.

  The ice maker 1 according to the present embodiment includes an evaporator E including an inner tube 12 and an outer tube 13 and a blade mechanism described below, and the axes of the inner tube 12 and the outer tube 13 are horizontal. This is a horizontal type ice maker that is placed in the area. The evaporator E is a liquid-filled evaporator in which most of the annular space 14 between the inner pipe 12 and the outer pipe 13 is used as a liquid refrigerant, and can increase the heat exchange efficiency between the refrigerant and seawater. Further, by making most of the annular space 14 a liquid refrigerant, the refrigerating machine oil in the liquid-filled evaporator can be easily discharged from the liquid-filled evaporator. By returning to, the insufficient lubrication of the compressor 2 can be suppressed, and the reliability can be improved.

  The inner tube 12 is an element through which seawater as a medium to be cooled passes, and is made of a metal material such as stainless steel or iron. The inner tube 12 has a cylindrical shape and is disposed inside the outer tube 13. Both ends of the inner tube 12 are closed, and a blade mechanism 15 for scraping the sherbet-like ice slurry generated on the inner peripheral surface of the inner tube 12 and dispersing the same in the inner tube 12 is provided therein. ing. A seawater inlet pipe 16 through which seawater is supplied into the inner pipe 12 is provided at one axial end (right side in FIG. 2) of the inner pipe 12, and the other axial end of the inner pipe 12 (left side in FIG. 2). ) Is provided with a seawater outlet pipe 17 through which seawater is discharged from the inner pipe 12.

  The outer tube 13 has a cylindrical shape, and is made of a metal material such as stainless steel or iron like the inner tube 12. A plurality (three in this embodiment) of refrigerant inlet pipes 18 are provided in a lower portion of the outer tube 13, and a plurality (two in this embodiment) of refrigerant outlet tubes 19 are provided in an upper portion of the outer tube 13. Is provided. A refrigerant supply port 20 for supplying a refrigerant into the annular space 14 is formed at an upper end of the refrigerant inlet pipe 18, and a refrigerant outlet 21 for discharging the refrigerant in the annular space 14 is formed at a lower end of the refrigerant outlet pipe 19. .

  The blade mechanism 15 includes a rotating shaft 22, a support bar 23, a blade 24, and a motor 26, as shown in FIGS. The other end of the rotating shaft 22 in the axial direction is provided to extend to the outside from a flange 25 provided at the other end of the inner tube 12 in the axial direction, and is connected to a motor 26 that constitutes a driving unit that drives the rotating shaft 22. . Support bars 23 are erected at predetermined intervals on the peripheral surface of the rotating shaft 22, and a blade 24 is attached to the tip of the support bar 23. The blade 24 is made of, for example, a band-shaped member made of a synthetic resin, and has a tapered shape at the side edge on the front side in the rotation direction.

  Due to the annular space 14 formed between the outer peripheral surface of the inner tube 12 and the inner peripheral surface of the outer tube 13, a refrigerant supply port 20 formed at a lower portion of the outer tube 13 is connected to an upper portion of the outer tube 13. A refrigerant path to the formed refrigerant outlet 21 is formed. In the present embodiment, the inner pipe 12 and the outer pipe 13 constituting the evaporator E are disposed such that one axis of the inner pipe 12 and the outer pipe 13 is vertically displaced from the other axis. I have. Specifically, as shown in FIG. 4 (b), the axis Oi of the inner tube 12 is disposed so as to be shifted downward with respect to the axis Oo of the outer tube 13. FIG. 4 (a) shows a cross section of a conventional horizontal type double-pipe liquid-filled evaporator which is disposed so that the axis of the inner pipe and the axis of the outer pipe coincide with each other. The width of the annular space between the outer peripheral surface of the inner tube and the inner peripheral surface of the outer tube is constant from the refrigerant supply port to the refrigerant discharge port.

  As shown in FIG. 4B, by eccentrically lowering the axis Oi of the inner tube 12 with respect to the axis Oo of the outer tube 13, in a cross section perpendicular to the axial direction of the inner tube 12, The width w2 of the annular space 14 at the end point on the end point side of the path is made larger than the width w1 of the annular space 14 at the end point on the start point side of the path of the refrigerant, so that the refrigerant path is enlarged so that the path of the refrigerant is expanded. A part can be provided. In the refrigerant path expanding section, the width of the outlet side space is larger than the width of the inlet side space of the refrigerant path expanding section, and it is possible to suppress an increase in the refrigerant flow rate when forming occurs as described later. it can. In the refrigerant path enlarging section in the present embodiment, the entire path of the refrigerant in the evaporator E is a refrigerant path enlarging section, the starting point side end of the path is an inlet of the refrigerant path enlarging section, and the end point of the path is The side end is an outlet of the refrigerant path enlarging section. It should be noted that a refrigerant path enlarging portion may be provided in a part of the refrigerant path.

  By making the width of the upper annular space 14 larger than the width of the lower annular space 14, forming occurs when the refrigerant moves from the refrigerant supply port 20 to the refrigerant discharge port 21 through the path formed by the annular space 14. Even if it does, since the volume near the end point side of the path (the outlet side of the refrigerant path expanding section) becomes larger than the volume near the start point side of the path (the inlet side of the refrigerant path expanding section), the refrigerant due to the forming is formed. Can be suppressed from increasing. As a result, it is possible to suppress the liquid refrigerant from being discharged from the refrigerant discharge port 21, and to reduce the size of the accumulator 7 provided on the inlet side of the compressor 2. Also, since the inner pipe 12 is eccentric downward, the area where the liquid refrigerant contacts the outer peripheral surface of the inner pipe 12 is smaller than that in the case where the inner pipe 12 is concentric with the outer pipe shown in FIG. You can do much. As a result, the efficiency of heat transfer between the refrigerant and the seawater in the inner pipe 12 can be improved, and the capacity of the evaporator E can be improved.

  The amount of vertical displacement or eccentricity of the inner tube 12 with respect to the outer tube 13, in other words, the vertical distance G between the axis Oo of the outer tube 13 and the axis Oi of the inner tube 12 is particularly limited in the present disclosure. However, assuming that the inner diameter of the outer tube 13 is Do, the outer diameter of the inner tube 12 is Di, and L = (Do−Di) / 2, the distance G is not less than 0.42 L and not more than 0.74 L. Is desirable. If the distance G is larger than 0.74 L, the pressure loss due to the flow of the refrigerant may be excessive. On the other hand, if the distance G is smaller than 0.42 L, the width of the space at the end point on the end point side of the path may be reduced. The width may not be sufficiently larger than the width of the space at the starting point end of the path, and the above-described increase in the flow rate of the refrigerant may not be suppressed. In order to effectively suppress the increase in the flow velocity of the refrigerant without excessively increasing the pressure loss due to the flow of the refrigerant, the distance G is more preferably 0.55 L or more and 0.70 L or less.

Next, an example of calculating the desirable eccentric distance G will be described.
FIG. 5 is an explanatory diagram showing the eccentricity of the inner tube 12 and the outer tube 13, and FIG. 6 is a graph showing the relationship between the eccentric distance and the clearance between the inner and outer tubes. In FIGS. 5 and 6, ro is the inner radius of the outer tube (= 2 / Do), and ri is the inner radius of the inner tube (= 2 / Di).
In the present embodiment, the desired eccentric distance is premised on the assumption that the flow rates of the refrigerant at the inlet and the outlet of the evaporator composed of the inner pipe 12 and the outer pipe 13 are equal to each other, which is an optimal state as the evaporator. G is selected.

When the clearance of the inner and outer tubes when the inner tube angle θ (see FIG. 5) changes from 0 (evaporator inlet) to π (evaporator outlet), the clearance when θ = 0 is ro-ri-G. Yes, the clearance when θ = π is ro-ri + G. The clearance ratio A from when θ becomes 0 to π is represented by the following equation (1).
Clearance ratio A = (ro-ri + G) / (ro-ri-G) (1)

Further, when the ice making machine is operated under the following conditions using R410A as the refrigerant, the specific volume ratio of the refrigerant at the inlet and the outlet of the evaporator is about 4.5 from the physical property value of the refrigerant.
Evaporation temperature: -15 ° C
Dryness of refrigerant at evaporator inlet: 0.2
Dryness of refrigerant at evaporator outlet: 0.95

Therefore, the clearance ratio that matches the specific volume ratio of 4.5 is the optimum value, and it is most desirable that (ro-ri + G) / (ro-ri-G) in Expression (1) be 4.5.
When this is deformed, the eccentric distance G becomes G = 0.64 (ro-ri), that is, G = 0.64L.
However, the effect of the present disclosure is obtained in the range of 2.5 to 6.5, and the further effect is obtained in the range of 3.5 to 5.5, centering on the optimum value “4.5”.
From the above, it is desirable that the eccentric distance G is 0.42 (ro-ri) to 0.74 (ro-ri), that is, 0.42 L to 0.74 L, and 0.55 (ro-ri) to More preferably, it is 0.70 (ro-ri), that is, 0.55 L to 0.70 L.

  In the present embodiment, the width of the upper annular space 14 is reduced by eccentrically lowering the axis Oi of the cylindrical inner tube 12 with respect to the axis Oo of the cylindrical outer tube 13. Since the width of the space is larger than the width of 14, the width of the space is gradually and continuously increased from the start point end to the end point end of the refrigerant path. Thus, it is possible to suppress an increase in pressure loss due to the flow of the refrigerant as compared with a case where the width of the space is discontinuously or rapidly increased.

[Other modifications]
The present disclosure is not limited to the embodiments described above, and various modifications can be made within the scope of the claims.
For example, in the above-described embodiment, the cylindrical tubes are used as the inner tube and the outer tube that constitute the double-tube evaporator. If both sides can be enlarged, both need not be cylindrical. For example, as shown in FIG. 7, the inner tube 32 may have a cylindrical shape, and the outer tube 33 may have a lower semicircular section and a rectangular upper section. Also in this case, the width of the annular space 34 between the inner pipe 32 and the outer pipe 33 can be made larger on the refrigerant outlet side than on the refrigerant supply port side to provide the refrigerant path enlarging portion.

  In the above-described embodiment, the accumulator is provided on the inlet side of the compressor. However, the accumulator crosses the annular space that can be set by the cross-sectional shape of the inner pipe and the outer pipe and the arrangement of both pipes. By appropriately selecting the surface shape, it is possible to omit this. As shown in FIG. 8, a double-tube superheater (heat exchanger) 40 is disposed on the outlet side of the ice making machine 1, and the refrigerant discharged from the evaporator constituting the ice making machine 1 is cooled. By heating with the refrigerant condensed in the heat source side heat exchanger 3 and then sending it to the compressor 2, in combination with the above-described liquid refrigerant discharge suppression effect of the liquid-filled evaporator of the present disclosure, the accumulator may be omitted. it can. In FIG. 8, components or elements common to those of the ice making system shown in FIG. 1 are denoted by the same reference numerals, and descriptions thereof will be omitted for simplicity.

  In the above-described embodiment, seawater is used as the medium to be cooled. However, the invention is not limited to this, and ethylene glycol, brine, or the like may be used as the medium to be cooled.

1: Ice machine 2: Compressor 3: Heat source side heat exchanger 4: Four way switching valve 5: Use side expansion valve 6: Heat source side expansion valve 7: Accumulator 8: Receiver 9: Seawater tank 10: Pump 11: Ventilation fan 12: Inner tube 13: Outer tube 14: Annular space 15: Blade mechanism 16: Seawater inlet tube 17: Seawater outlet tube 18: Refrigerant inlet tube 19: Refrigerant outlet tube 20: Refrigerant supply port 21: Refrigerant discharge port 22: Rotating shaft 23: Support bar 24: Blade 25: Flange 26: Motor 32: Inner tube 33: Outer tube 34: Annular space A: Ice making system E: Evaporator

Claims (5)

It has an outer pipe (13) and an inner pipe (12) provided in the outer pipe (13). A medium to be cooled flows into the inner pipe (12), and the inner pipe (12) is connected to the outer pipe. A double-pipe liquid-filled evaporator (E) for flowing a refrigerant into a space (14) between the pipe (13),
The liquid-filled evaporator (E) comprises:
The outer pipe (13) and the inner pipe (12) are horizontal and each axis is horizontal;
Due to the space (14), a refrigerant path from a refrigerant supply port (20) formed at a lower portion of the outer tube (13) to a refrigerant discharge port (21) formed at an upper portion of the outer tube (13). Is configured,
The refrigerant path has a refrigerant path enlarging portion in which a width of the space increases in a direction toward the refrigerant discharge port (21) in a cross section perpendicular to the axial direction of the inner pipe (12). Double tube type liquid evaporator (E).   The outer pipe (13) and the inner pipe (12) are cylindrical, and the outer pipe (13) and the inner pipe (12) are eccentric in one direction with respect to the other axis in the vertical direction. The double-tube, full-fill evaporator (E) according to claim 1, wherein   The inner diameter of the outer pipe (13) is Do, the outer diameter of the inner pipe (12) is Di, the vertical distance between the axis of the outer pipe (13) and the axis of the inner pipe (12) is G, The double-tube type liquid-filled evaporator (E) according to claim 2, wherein the distance G is not less than 0.42L and not more than 0.74L, where L = (Do-Di) / 2.   4. The width of the space (14) in the refrigerant path expanding section is gradually and continuously increased from the inlet side to the outlet side of the refrigerant path expanding section. 5. 2. A double-tube type liquid-filled evaporator (E).   An ice making machine (1) comprising the double-tube type liquid-filled evaporator (E) according to any one of claims 1 to 4.

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