WO2020136735A1

WO2020136735A1 - Falling liquid film type tube ice machine

Info

Publication number: WO2020136735A1
Application number: PCT/JP2018/047713
Authority: WO
Inventors: 郁朗赤田; 耕作西田; 憲一小畠
Original assignee: 株式会社前川製作所
Priority date: 2018-12-26
Filing date: 2018-12-26
Publication date: 2020-07-02
Also published as: JP6965464B2; JPWO2020136735A1

Abstract

A falling liquid film type tube ice machine according to one embodiment comprises: a casing; a plurality of heat transfer tubes that extend along the vertical direction inside the casing; and a header for storing a refrigerant, the header being provided in the region of the inner space of the casing where the upper ends of the heat transfer tubes are arranged. The heat transfer tubes are each configured so as to be supplied with the refrigerant from the header so that a liquid film of the refrigerant is formed on the outer surface of the heat transfer tube.

Description

Flowing liquid film tube ice machine

The present disclosure relates to a vertical falling liquid film tube ice maker.

Conventionally, a tube ice maker has a liquid-filled evaporator with a heat transfer tube built in and the shell side filled with refrigerant. By boiling the refrigerant at a low temperature, the water flowing in the heat transfer tube is cooled and ice is generated on the inner wall of the heat transfer tube. When the thickness of the ice has increased to some extent, the hot gas of the refrigerant is injected into the shell to melt the ice on the inner wall of the heat transfer tube, the ice drops to the bottom due to its own weight, and it is crushed at regular intervals to produce tube ice. To do. Patent Document 1 discloses an ice-making machine equipped with a liquid-filled heat exchanger.

Japanese Patent Laid-Open No. 06-147707

An ice machine equipped with a liquid-filled evaporator requires a large amount of refrigerant in order to fill the casing with the refrigerant liquid, and the head of the refrigerant liquid causes a pressure distribution in the depth direction, resulting in a depth of about 2 m. In a full-fill type evaporator, the evaporation temperature at the bottom is about 1° C. higher than that at the top, so there is a problem that the ice thickness becomes uneven. Further, since heat transfer on the refrigerant side is nucleate boiling heat transfer, the heat transfer rate becomes low, and it takes time to make ice. Furthermore, when hot gas is injected into the shell side to raise the temperature of the refrigerant during de-icing, a large amount of heat is required to raise the temperature of a large amount of refrigerant liquid that is supercooled at a low temperature above the melting point of ice. At the same time, the convective heat transfer with the refrigerant liquid heated and stirred by the hot gas reduces the heat transfer coefficient with the ice formed inside the heat transfer tube, and there is a problem that it takes time to remove the ice. is there.

An embodiment is aimed at proposing an ice-making machine capable of reducing the amount of refrigerant and increasing the efficiency of ice-making and de-icing.

(1) A falling liquid film tube ice maker according to one embodiment is
A casing,
A plurality of heat transfer tubes extending along the vertical direction inside the casing,
A header for storing the refrigerant, which is provided in a region where the upper end of the heat transfer tube is disposed in the internal space of the casing,
Equipped with
The heat transfer tube is configured to receive the supply of the refrigerant from the header so that a liquid film of the refrigerant is formed on an outer surface of the heat transfer tube.
Here, “extending along the vertical direction” includes extending with an inclination within an angle at which the liquid film on the surface of the heat transfer tube is secured.

In the ice making process, the refrigerant liquid forms a falling liquid film on the outer surface of the heat transfer tube and evaporates by heat exchange with the ice making water inside the heat transfer tube. Since the liquid film is a thin film and has no retention, the resistance to evaporation is small and the heat exchange is efficiently performed. In this way, the refrigerant liquid film and the ice-making water flowing down the inside of the heat transfer tube are heat-exchanged, so that the amount of the refrigerant can be significantly reduced as compared with the full liquid type. Further, since the refrigerant liquid film flows down along the outer surface of the heat transfer tube, a uniform liquid film can be formed as compared with a method of spraying the refrigerant liquid on the outer surface of the heat transfer tube using a spray or the like. Further, since the evaporation heat transfer is performed by a thin film, a high heat transfer coefficient can be obtained even with a low heat flux, and the ice making time can be greatly shortened as compared with the full liquid type. Further, since the refrigerant flows down along the outer surface of the heat transfer tube, the evaporation temperature becomes constant in the vertical direction, and the ice thickness cannot be uneven in the vertical direction. Further, in the de-icing step, since the refrigerant liquid retained in the casing is small, the refrigerant liquid can reach the saturation temperature equal to or higher than the melting point of ice in a short time by injecting the hot gas for de-icing, and the hot gas is Since it condenses and flows down along the vertical direction of the outer surface of the heat transfer tube, there is no retention of the condensate, and the heat of condensation of the hot gas is efficiently transferred to the ice side, so that the deicing time can be shortened. Therefore, the ice making capacity can be improved, and since the amount of the refrigerant liquid stored in the casing is small, it is possible to prevent the refrigerant liquid in the casing from returning to the compressor as mist.

(2) In one embodiment, in the configuration of (1) above,
A tube plate to which the upper end of the heat transfer tube is fixed;
An upper ice-making water storage portion formed above the tube sheet,
Equipped with
The header is formed below the tube sheet.
According to the configuration of (2) above, the upper ice making water storage part is arranged above the tube sheet and the refrigerant storage header is arranged below the tube sheet with the tube sheet as a boundary, so that the ice making water inside the heat transfer tube is arranged. It is possible to make the structure for supplying the refrigerant and forming the refrigerant liquid film on the outer surface of the heat transfer tube compact.

(3) In one embodiment, in the configuration of (1) or (2) above,
An inlet for the refrigerant is provided at a lower portion of the casing so as to communicate with the internal space,
A refrigerant circulation path for returning the refrigerant liquid stored in the lower portion of the internal space to the header is provided.
According to the above configuration (3), since the refrigerant inlet is provided in the lower portion of the casing, the refrigerant liquid supplied into the casing does not break the refrigerant liquid film formed on the outer surface of the heat transfer tube. It is possible to maintain a high heat transfer coefficient with the ice making water on the inner surface of the heat transfer tube.

(4) In one embodiment, in any one of the configurations (1) to (3) above,
An outlet for the refrigerant is provided in an upper portion of the casing so as to communicate with the internal space.
According to the above configuration (4), since the refrigerant outlet is located at the upper part of the casing and is located away from the refrigerant liquid accumulated in the lower part of the internal space, only the refrigerant gas can be discharged from the refrigerant outlet. As a result, it is possible to prevent liquid backing to the compressor that constitutes the refrigerator.

(5) In one embodiment, in any one of the configurations (1) to (4) above,
The refrigerant having a liquid level of 1/10 or less of the height of the internal space is stored in the lower part of the internal space.
According to the configuration of (5), since the refrigerant liquid having a liquid level of 1/10 or less of the internal space height is stored in the internal space of the casing, it is possible to make ice with a small amount of the refrigerant. Become. In addition, by setting the liquid level of the refrigerant liquid to 1/10 or less of the height of the internal space, the refrigerant liquid surface can be moved away from the refrigerant outlet in the upper part of the internal space, so that the refrigerant liquid reaches the refrigerant outlet. Does not mix. Therefore, in addition to being able to prevent liquid back to the compressor, in a refrigerator that supplies a refrigerant, an accumulator that separates gas-liquid from the refrigerant outlet to the compressor, and a liquid-gas heat exchanger for gasifying the refrigerant liquid. Is unnecessary.

(6) In one embodiment, in any of the configurations (1) to (5) above,
A hot gas inlet formed in the lower portion of the casing to communicate with the internal space;
A hot gas outlet formed so as to communicate with the internal space in the upper portion of the casing;
Equipped with.
In the de-icing step, hot gas is supplied from the hot gas inlet to the internal space of the casing in order to de-ice the tube ice formed on the inner surface of the heat transfer tube. According to the above configuration (6), since the hot gas inlet is formed in the lower part of the casing, the hot gas is supplied into the refrigerant liquid accumulated in the lower part of the inner space of the casing, and the refrigerant liquid is vigorously stirred. As a result, the heat transfer coefficient with the tube ice can be increased and the deicing time can be shortened. Further, in the vapor phase portion above the liquid surface of the refrigerant, the outer surface of the heat transfer tube is exposed to saturated vapor of hot gas. Therefore, the outer surface of the heat transfer tube is condensed heat transfer in which hot gas flows down while condensing, and the heat transfer rate about twice that of the deicing process of the conventional full-fill type ice maker can be obtained. Can be shortened.

(7) In one embodiment, in any one of the configurations (1) to (6) above,
A cutter is provided below the plurality of heat transfer tubes for cutting the tube ice that slides down from the inner surface of the heat transfer tubes under its own weight during deicing.
According to the configuration of (7), since the cutter is provided, in the deicing step, the tube ice that slides off from the inner surface of the heat transfer tube by its own weight can be cut into an appropriate length and supplied to the destination.

(8) In one embodiment, in the configuration of (2) above,
A lower ice making water storage portion provided below the plurality of heat transfer tubes,
A water circulation path connecting the lower ice making water storage part and the upper ice making water storage part,
A water circulation pump provided in the water circulation path for circulating the ice making water accumulated in the lower ice making water storage portion to the upper ice making water storage portion,
A level sensor for detecting a liquid level of the ice making water accumulated in the lower ice making water storage part;
A control unit for controlling the operation of the water circulation pump based on the detection value of the level sensor;
Equipped with.
According to the configuration of (8), since the liquid level of the ice making water accumulated in the lower ice making water storage portion can be controlled to a desired level in the ice making process, the ice making process can be smoothly performed.

(9) In one embodiment, in any one of the configurations (1) to (8) above,
A refrigerator for generating the refrigerant supplied to the header,
The refrigerator is
A refrigerant circuit,
A refrigeration cycle constituent device that is provided in the refrigerant circuit and includes a compressor, a condenser, a receiver, and an expansion valve,
Equipped with
The refrigerant is decompressed via the expansion valve and is supplied to the casing.
According to the configuration of (9) above, by including the refrigerator, the refrigerant as the cold heat source of the ice making machine can be supplied to the ice making machine.

(10) In one embodiment, in the configuration of (9) above,
A hot gas supply path communicating with the gas phase portion of the receiver and the internal space is provided.
According to the configuration of (10) above, by providing the hot gas supply passage, hot gas (refrigerant gas having a temperature higher than 0° C.) can be supplied to the internal space of the casing in the deicing process. Further, when hot gas is supplied from the vapor phase part of the receiver through the hot gas supply passage, the inside of the receiver is decompressed due to the supply of hot gas, and the refrigerant liquid inside the receiver is vaporized due to the decompression inside the receiver. Therefore, the hot gas can be replenished with the newly vaporized refrigerant gas.

(11) In one embodiment, in any one of the configurations (1) to (10) above,
The refrigerant is a natural refrigerant, an HFC refrigerant or an HFO refrigerant.
According to the above configuration (11), for example, NH ₃ among the refrigerants has a large surface tension. Due to this surface tension, a uniform refrigerant liquid film can be formed in the circumferential direction of the heat transfer tube. As a result, the amount of heat transferred to the ice making water can be improved.

According to some embodiments, in the falling film tube ice maker, the amount of refrigerant can be reduced, the cost can be reduced, and the efficiency of ice making and de-iceing can be improved, and the ice making capacity can be improved. Further, it is possible to prevent the thickness of ice from being uneven in the extending direction of the heat transfer tube, and it is possible to suppress liquid back to the compressor of the refrigerator that supplies the refrigerant.

It is a longitudinal cross-sectional view of the ice maker according to an embodiment. It is a system diagram which shows the time of ice making of the refrigerator which concerns on one Embodiment. It is a system diagram which shows the time of de-icing of the refrigerator which concerns on one Embodiment.

Hereinafter, some embodiments of the present invention will be described with reference to the accompanying drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described as the embodiments or shown in the drawings are not intended to limit the scope of the present invention thereto, but are merely illustrative examples.
For example, the expression "relative or absolute" such as "in a certain direction", "along a certain direction", "parallel", "orthogonal", "center", "concentric" or "coaxial" is strict. In addition to representing such an arrangement, it also represents a state of relative displacement or a relative displacement with an angle or distance to the extent that the same function can be obtained.
For example, expressions such as "identical", "equal", and "homogeneous" that indicate that they are in the same state are not limited to strict equality, but also include tolerances or differences in the degree to which the same function is obtained. It also represents the existing state.
For example, the representation of a shape such as a quadrangle or a cylinder does not only represent a shape such as a quadrangle or a cylinder in a geometrically strict sense, but also an uneven portion or a chamfer within a range in which the same effect can be obtained. The shape including parts and the like is also shown.
On the other hand, the expressions “comprising”, “comprising”, “comprising”, “including”, or “having” one element are not exclusive expressions excluding the existence of other elements.

FIG. 1 is a vertical cross-sectional view of a falling liquid film tube ice maker 10 according to an embodiment. The ice maker 10 includes a plurality of heat transfer tubes 14 inside the casing 12, and the heat transfer tubes 14 extend in the vertical direction. A refrigerant header 16 for storing the refrigerant liquid is provided in an area of the inner space S ₀ (outer space of the heat transfer tube 14) of the casing 12 where the upper end of the heat transfer tube 14 is arranged. The refrigerant liquid supplied from the refrigerant header 16 forms a refrigerant liquid film on the outer surface of the heat transfer tube 14. The refrigerant liquid film formed on the outer surface of the heat transfer tube 14 flows down along the outer surface of the heat transfer tube.
Ice-making water Wi is supplied from the upper end opening of the heat-transfer tube 14 to the inside of the heat-transfer tube 14, and the ice-making water Wi is cooled by a refrigerant liquid film formed on the outer surface of the heat-transfer tube 14 to form a cylindrical shape on the inner surface of the heat-transfer tube 14. Tube ice Ti is formed.

The term "refrigerant" used here means that ice-making water Wi that changes its phase and flows down the inner surface of the heat transfer tube 14 is cooled by evaporation latent heat to make ice.

The formation of the refrigerant liquid film on the outer surface of the heat transfer tube and the supply of the ice-making water Wi to the inner side of the heat transfer tube are continuously performed until the tube ice Ti has a predetermined thickness. When the tube ice Ti reaches a predetermined thickness, the ice making process is switched to the deicing process. In the de-icing step, hot gas (refrigerant gas exceeding 0° C.) is supplied to the internal space S ₀ of the casing 12, and the tube ice Ti is separated from the inner surface of the heat transfer tube 14 due to the heat transferred from the hot gas to the heat transfer tube 14. It slides down due to its own weight.

According to the above configuration, in the ice making process, the refrigerant liquid forms a falling liquid film on the outer surface of the heat transfer tube and evaporates by heat exchange with the ice making water Wi inside the heat transfer tube. Since the liquid film is a thin film and has no retention, the resistance to evaporation is small and the heat exchange is efficiently performed. In this way, the refrigerant liquid film and the ice-making water Wi inside the heat transfer tube are heat-exchanged, so that the amount of the refrigerant can be significantly reduced as compared with the liquid-filled heat exchanger that stores the refrigerant liquid inside the casing 12. Further, since the refrigerant liquid film flows down along the outer surface of the heat transfer tube, a uniform liquid film can be formed on the outer peripheral surface of the heat transfer tube 14 as compared with a method of spraying the refrigerant liquid on the heat transfer tube by using a spray or the like. The heat transfer coefficient can be improved. Further, in the case of a refrigerant that changes phase, since the evaporation heat transfer is a thin film, a high heat transfer coefficient can be obtained even with a low heat flux, and the ice making time can be greatly shortened as compared with the full liquid type. Further, since the refrigerant flows down along the outer surface of the heat transfer tube, the evaporation temperature becomes constant in the vertical direction, so that the ice thickness cannot be uneven in the vertical direction. Further, in the deicing step, since the refrigerant liquid retained in the casing 12 is small, the refrigerant liquid can reach the saturation temperature equal to or higher than the melting point of ice in a short time by injecting the hot ice for deicing, and Is condensed and flows down along the vertical direction of the outer surface of the heat transfer tube, so that the condensate is not retained and the heat of condensation of the hot gas is efficiently transferred to the ice side, so that the deicing time can be shortened. Therefore, the ice making capacity can be improved, and liquid back to the compressor 64 (see FIGS. 2 and 3) that constitutes the refrigerator 60 that supplies the refrigerant to the ice making machine 10 can be suppressed, as will be described later.

In one embodiment, as shown in FIGS. 2 and 3, a refrigerator 60 is provided. The refrigerator 60 includes a refrigerating cycle constituent device including a compressor 64, a condenser 66, a receiver 68, and an expansion valve 70 in a refrigerant circuit 62 in which a refrigerant circulates.
2 shows an ice making step, and FIG. 3 shows a deicing step. In the ice making process, the refrigerant gas discharged from the compressor 64 is cooled by the condenser 66 and becomes a refrigerant liquid, which is sent to the receiver 68. The refrigerant liquid r is stored in the receiver 68, the refrigerant liquid r is decompressed via the expansion valve 70, and is supplied to the casing 12 of the ice maker 10.
According to this embodiment, by including the refrigerator 60, the refrigerant as the cold heat source of the ice making machine 10 can be supplied to the ice making machine 10.

In one embodiment, as shown in FIG. 1, a tube sheet 18 is provided on the upper part of the casing 12, and the upper end of the heat transfer tube 14 is fixed to the tube sheet 18. An upper ice making water storage portion 20 is provided above the tube sheet 18, and a refrigerant header 16 is provided below the tube sheet 18. Thus, the upper ice-making water storage section 20 is arranged above the tube sheet 18 with the tube sheet 18 as a boundary, and the refrigerant header 16 is arranged below the tube sheet 18.
In one embodiment, the upper ice-making water storage unit 20 is formed of a hollow container capable of storing the ice-making water Wi, the bottom surface is formed of the tube plate 18, and the upper end of the heat transfer tube 14 is opened at the bottom surface. Further, the bottom surface of the refrigerant header 16 is composed of a bottom wall 18a arranged along the horizontal direction, and an annular gap (not shown) for allowing the refrigerant liquid film to flow down between the bottom wall 18a and the outer peripheral surface of the heat transfer tube 14. ) Is formed. Further, the upper surface of the refrigerant header 16 is composed of the tube plate 18.

In one embodiment, as shown in FIG. 1, is provided in the lower portion of the casing 12 as the refrigerant inlet pipe 22 communicates with the lower interior space S _0, the refrigerant header refrigerant liquid r which stores the bottom of the inner space S ₀ A refrigerant circulation pipe 24 for returning to 16 is provided. The coolant liquid r is supplied from the coolant inlet pipe 22 to the internal space S ₀ , and the coolant liquid r stored in the lower portion of the internal space S ₀ is sent to the coolant header 16 by the coolant circulation pump 26 provided in the coolant circulation pipe 24. .. In this way, by circulating the refrigerant through the refrigerant circulation pipe 24, the tube ice Ti can be formed to have a predetermined thickness.
According to this embodiment, the refrigerant inlet pipe 22 because it is provided in the lower portion of the internal space S _0, refrigerant liquid r supplied to the internal space S ₀ is not broken refrigerant liquid film formed on the heat transfer tube outer surface. Therefore, the heat transfer coefficient between the refrigerant liquid film and the ice-making water Wi on the inner surface of the heat transfer tube can be kept high.

In one embodiment, a refrigerant outlet pipe 28 is provided in the lower portion of the casing 12 so as to communicate with the internal space S ₀ , and a refrigerant inlet pipe 30 is provided in the upper portion of the casing 12 so as to communicate with the refrigerant header 16. The refrigerant liquid r stored in the internal space S ₀ in the lower part of the casing 12 is sent from the refrigerant outlet pipe 28 to the refrigerant inlet pipe 30 to the refrigerant header 16 by the refrigerant circulation pump 26 from the refrigerant outlet pipe 28.

In one embodiment, the refrigerant outlet pipe 32 from which the refrigerant gas vaporized by heat exchange with the ice-making water Wi is discharged is provided in the upper portion of the casing 12 so as to communicate with the internal space S ₀ . According to this embodiment, the refrigerant outlet pipe 32 is located at the top of the inner space S _0, is in a position away from the refrigerant liquid r accumulated in the lower portion of the internal space S _0, refrigerant liquid along the heat transfer tube 14 is liquid film Therefore, only the refrigerant gas can be discharged from the refrigerant outlet pipe 32. As a result, liquid back to the compressor 64 can be prevented.

In one embodiment, in the ice making step, the operation is performed such that the liquid level of the refrigerant liquid forms a liquid level (H in FIG. 1) of about 1/10 of the vertical direction (height) of the internal space S ₀ . This enables ice making with a small amount of refrigerant. Further, by setting the liquid level H of the refrigerant liquid to about 1/10 of the vertical direction (height), the refrigerant liquid surface can be kept away from the refrigerant inlet pipe 22 in the upper part of the internal space S ₀ , so that the refrigerant inlet The refrigerant liquid does not mix with the refrigerant discharged from the pipe 22. Therefore, liquid back to the compressor 64 can be prevented, and in the refrigerator 60 that supplies the refrigerant, the accumulator that separates gas and liquid and the refrigerant liquid are gasified in the refrigerant circuit 62 that leads from the refrigerant outlet pipe 32 to the compressor 64. It is not necessary to dispose a liquid gas heat exchanger.
In one embodiment, the tube plate 36 is provided in the lower portion of the casing 12, and the internal space S ₀ can store the refrigerant liquid r with the tube plate 36 as the bottom surface.

In one embodiment is provided with a hot gas inlet pipe 34 formed in the lower portion of the internal space S _0, and the hot gas outlet pipe 32 formed in the upper portion of the internal space S _0, the. In the deicing step, hot gas is supplied from the refrigerator 60 to the internal space S ₀ in order to deice the tube ice Ti formed on the inner surface of the heat transfer tube.
According to this embodiment, since the hot gas inlet pipe 34 is formed in the lower portion of the internal space S ₀ , the hot gas is supplied into the refrigerant liquid accumulated in the lower portion of the internal space S ₀ and vigorously agitates the refrigerant liquid. .. As a result, the heat transfer coefficient between the refrigerant liquid and the tube ice Ti can be increased, and the deicing time can be shortened. Further, in the vapor phase portion above the liquid surface of the refrigerant, the outer surface of the heat transfer tube 14 is exposed to saturated vapor of hot gas. Therefore, the outer surface of the heat transfer tube 14 is condensed heat transfer in which hot gas flows while condensing, and a heat passage rate that is about twice that of the deicing process of the conventional full-fill type ice maker can be obtained, so that the deicing time is shortened. it can.
In the embodiment shown in FIG. 1, the hot gas outlet pipe 32 is also used as the refrigerant outlet pipe.

In one embodiment, as shown in FIG. 1, a cutter 38 is provided below the plurality of heat transfer tubes 14. In the de-icing step, the tube ice Ti that slides off from the inner surface of the heat transfer tube 14 by its own weight can be cut into an appropriate length and supplied to the user.
In one embodiment, the cutter 38 is provided inside the lower ice making water storage portion 42 provided below the plurality of heat transfer tubes 14. The lower ice making water storage part 42 is formed of a hollow container, and is capable of storing ice making water Wi therein.
In one embodiment, the cutter 38 is configured to be rotatable about a rotation shaft 38a and is rotated by a driving unit (for example, a motor) 40. The length of the tube ice Ti to be cut can be adjusted by appropriately controlling the rotation speed of the cutter 38 by the drive unit 40 in accordance with the falling speed of the tube ice Ti sliding off the heat transfer tube 14 during de-icing.

In one embodiment, as shown in FIG. 1, a water circulation pipe 44 that connects the lower ice making water storage part 42 and the upper ice making water storage part 20 is provided, and the water circulation pipe 44 has the ice making water accumulated in the lower ice making water storage part 42. A water circulation pump 46 for circulating the water Wi to the upper ice-making water storage portion 20 is provided. Further, a level sensor 48 for detecting the liquid surface level of the ice making water Wi accumulated in the lower ice making water storage portion 42 is provided, and the control portion 50 controls the operation of the water circulation pump 46 based on the detection value of the level sensor 48. ..
According to this embodiment, in the ice making step, the ice making water Wi supplied to the inside of the heat transfer tube 14 is circulated to the heat transfer tube 14 via the water circulation tube 44, whereby the tube ice Ti can be formed to a predetermined thickness. .. Further, since the liquid surface level of the ice making water Wi accumulated in the lower ice making water storage portion 42 can be controlled to a desired level, the ice making process can be smoothly performed.
In one embodiment, when the ice making water Wi in the upper ice making water storage part 20 and the lower ice making water storage part 42 becomes insufficient, makeup water can be injected into the upper ice making water storage part 20 or the lower ice making water storage part 42. .. After the tube ice Ti production is completed in the ice making step, the circulation of the ice making water Wi is stopped.

In one embodiment, a bottom plate 52 having a mesh-shaped opening is provided inside the lower ice making water storage part 42. The inner space of the lower ice making water storage portion 42 is partitioned by the bottom plate 52 into an upper region including an outlet opening 54 of the tube ice Ti and a lower region including an outlet opening communicating with the water circulation pipe 44. As a result, the tube ice Ti cut by the cutter 38 and the water partially melted in the deicing process are separated by the bottom plate 52, and only the tube ice Ti can be discharged from the outlet opening 54 to the outside of the lower ice making water reservoir 42. .. The ice-making water Wi that has flowed down to the lower region is returned to the upper ice-making water storage portion 20 via the water circulation pipe 44.

In one embodiment, the hot gas supply path 72 that communicates with the gas phase portion of the receiver 68 and the internal space S ₀ is provided. According to this embodiment, by providing the hot gas supply path 72, hot gas can be supplied to the internal space S ₀ in the deicing step. Since the cooling operation of the condenser 66 is not performed in this step, the receiver gas phase portion is maintained at a high temperature. Further, when hot gas is supplied from the gas phase portion of the receiver 68 via the hot gas supply path 72, the inside of the receiver 72 is decompressed as the hot gas is supplied, and the refrigerant liquid inside the receiver is decompressed as the pressure inside the receiver is reduced. Is vaporized, the hot gas can be supplemented by the vaporized refrigerant gas.

In one embodiment, a natural refrigerant (for example, NH ₃ , CO ₂ , propane, isobutane, etc.), an HFC refrigerant (for example, R134a, R32, R404A, R410A, etc.), or an HFO refrigerant (for example, R1234yf) is used as the refrigerant. To be
According to this embodiment, of the refrigerants, NH _3, for example, has a large surface tension. This surface tension acts so that the refrigerant liquid film wraps around the heat transfer tube 14 in the circumferential direction, so that a uniform refrigerant liquid film can be formed in the circumferential direction of the heat transfer tube. As a result, the amount of heat transferred to the ice making water Wi can be improved.

According to some embodiments, it is possible to realize a falling liquid film type ice making machine that can reduce the amount of refrigerant and can make the apparatus compact, and also can improve the efficiency of ice making and de-icing.

10 Ice Maker 12 Casing 14 Heat Transfer Pipe 16

Refrigerant Header

18, 36 Tube Plate 20 Upper Ice

Making Water Storage

22, 30 Refrigerant Inlet Pipe 24 Refrigerant Circulation Pipe 26 Refrigerant Circulation Pump 28 Refrigerant Outlet Pipe 32 Refrigerant Outlet Pipe/Hot Gas Outlet Pipe 34 Hot gas inlet pipe 38 Cutter 38a Rotating shaft 40 Drive part 42 Lower ice making water storage part 44 Water circulation pipe 46 Water circulation pump 48 Level sensor 50 Control part 52 Bottom plate 54 Outlet opening 60 Refrigerator 62 Refrigerant circuit 64 Compressor 66 Condenser 68 Receiver 70 Expansion valve 72 Hot gas supply path H Refrigerant liquid level S ₀ Internal space Ti tube Ice Wi Ice making water r Refrigerant liquid

Claims

A casing,
A plurality of heat transfer tubes extending along the vertical direction inside the casing,
A header for storing the refrigerant, which is provided in a region where the upper end of the heat transfer tube is provided in the inner space of the casing on the outer surface side of the heat transfer tube,
Equipped with
A falling liquid film tube ice maker, wherein the heat transfer tube is configured to receive the supply of the refrigerant from the header so that a liquid film of the refrigerant is formed on an outer surface of the heat transfer tube.
A tube plate to which the upper end of the heat transfer tube is fixed;
An upper ice-making water storage portion formed above the tube sheet,
Equipped with
The falling water film tube ice maker according to claim 1, wherein the header is formed below the tube sheet.
An inlet for the refrigerant is provided at a lower portion of the casing so as to communicate with the internal space,
The falling film ice-making machine according to claim 1 or 2, further comprising a refrigerant circulation path for returning the refrigerant liquid stored in the lower portion of the internal space to the header.
The falling film ice-making machine according to any one of claims 1 to 3, wherein an outlet of the refrigerant is provided in an upper portion of the casing so as to communicate with the internal space.
The falling liquid film tube ice according to any one of claims 1 to 4, wherein the refrigerant having a liquid level equal to or lower than 1/10 of a height of the internal space is stored in a lower portion of the internal space. Ice machine.
A hot gas inlet formed in the lower portion of the casing to communicate with the internal space;
A hot gas outlet formed so as to communicate with the internal space in the upper portion of the casing;
The falling liquid film tube ice maker according to any one of claims 1 to 5, further comprising:
7. A cutter provided below the plurality of heat transfer tubes for cutting tube ice that slides down from the inner surface of the heat transfer tubes by its own weight during de-icing, and the cutter is provided. Falling film tube ice machine.
A lower ice making water storage portion provided below the plurality of heat transfer tubes,
A water circulation path connecting the lower ice making water storage part and the upper ice making water storage part,
A water circulation pump provided in the water circulation path for circulating the ice making water accumulated in the lower ice making water storage portion to the upper ice making water storage portion,
A level sensor for detecting a liquid level of the ice making water accumulated in the lower ice making water storage part;
A control unit for controlling the operation of the water circulation pump based on the detection value of the level sensor;
The falling liquid film tube ice maker according to claim 2, further comprising:
A refrigerator for generating the refrigerant supplied to the header,
The refrigerator is
A refrigerant circuit,
A refrigeration cycle constituent device that is provided in the refrigerant circuit and includes a compressor, a condenser, a receiver, and an expansion valve,
Equipped with
The falling film ice maker according to any one of claims 1 to 8, wherein the refrigerant whose pressure has been reduced via the expansion valve is supplied to the casing.
The falling film ice maker according to claim 9, further comprising a hot gas supply passage communicating with a gas phase portion of the receiver and the internal space.
The falling film ice maker according to any one of claims 1 to 10, wherein the refrigerant is a natural refrigerant, an HFC refrigerant, or an HFO refrigerant.