JP2000334203A - Freezing and concentrating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the degree of concentration of a concentrated solution by providing a second heat exchanger at the downstream side of a first heat exchanger and returning the concentrated solution which is passed through the second heat exchanger to a concentrated solution tank, in the production process which is comprised of cooling the concentrated solution by the first heat exchanger to form flake ice and scratching off the formed ice. SOLUTION: When a freezing and concentrating apparatus is operated, a concentrated solution in a concentrated solution tank 7 is introduced into a concentrated solution inlet 1a of a vertical tube 1 by a circulating pump 8 and the concentrated solution is cooled by a cooling device 12 in a vertical path 24, thereby the concentrated solution is made flake ice and fixed on the inner wall surface of the vertical tube 1. Thereafter, the flake ice is scratched off by a spiral blade 3b of an ice scratching mechanism 3 and the scratched ice is heated to a prescribed temp. by the electric heat of a heating coil 11, thereby the concentrated solution fixed on the surface of the ice is separated. The separated concentrated solution flows down along the inner wall surface of the vertical tube 1 and flows out into a concentrated solution receiver 17 through a plurality of small holes 18. Furthermore, solid parts such as ice chips are captured by a metal net 19, and the concentrated solution is returned from a concentrated solution outlet 17a to the concentrated solution tank 7 through a concentrated solution return pipe 15.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a freeze-concentrator for cooling and freezing concentrated juices of fruits and vegetables and other various solutions to remove water and increase the concentration.

[0002]

2. Description of the Related Art Conventionally, a freeze-concentration method which is excellent in preservation of nutrient components and flavor components has been used for producing a concentrate such as a concentrated juice of fruits and vegetables. The freeze concentration method includes a suspension crystal concentration method and an interfacial advance freeze concentration method. Among them, the interfacial advancing freeze concentration method generates one ice crystal in the concentrated solution and concentrates the liquid phase, which is suitable for the concentration of a low concentration solution, and can greatly reduce the product cost. It is possible.

[0003] In the interfacial advancing freezing and concentrating method, there is a problem of concentrating a high-concentration solution, but a method that can solve this problem is a scraping heat transfer freezing and concentrating method using a scraping type heat exchanger. There is.

FIG. 3 shows an example of a freeze-concentrator using the scraping heat transfer freeze-concentration method as a comparative technique. In FIG. 3, reference numeral 1 denotes a vertical hollow cylinder that stands vertically, and 2 denotes the vertical cylinder.
Is a hollow horizontal cylinder connected to the upper end of the horizontal cylinder and connected in the horizontal direction. A vertical passage 24 for the concentrated liquid is formed inside the vertical cylinder 1 and separated from the concentrated liquid inside the horizontal cylinder 2. A horizontal passage 25 for conveying the flaked ice is formed.

[0005] Reference numeral 3 denotes a scraping mechanism inserted into the vertical passage 24, which is formed by winding a spiral blade 3b around the center shaft 3a along the longitudinal direction. Reference numeral 4 denotes a transport mechanism inserted in the horizontal passage 25, and a spiral blade 4b is provided around the center shaft 4a.
Wrapped around. A motor 5 is connected to the lower end of the scraping mechanism 3 in the vertical cylinder 1 and drives the same. A motor 6 is connected to an end of the transport mechanism 4 in the horizontal cylinder 2 and drives the same.

Reference numeral 12 denotes a cooling device provided on the outer periphery of the lower part of the vertical cylinder 1. The cooling device 12 has a function of an evaporator of a refrigeration cycle, and is connected to a compressor 9 for compressing the refrigerant via refrigerant pipes 13, 13 to condense the gas refrigerant compressed by the compressor 9. After that, it is led to the cooling device 12 via an expansion mechanism, and evaporated by the cooling device 12 to
The concentrated liquid introduced into the vertical passage 24 in the inside is cooled.

Reference numeral 7 denotes a concentrate tank for storing the concentrate.
A concentrated liquid pipe 14 having a circulation pump 8 is connected to the bottom opening of the tank 7. The other end of the concentrated liquid pipe 14 is connected to a concentrated liquid inlet 1a opened at the lower part of the front vertical cylinder 1.

Reference numeral 17 denotes a concentrate receiver provided on the outer periphery of the vertical cylinder 1. The concentrate receiver 17 is provided on the downstream side of the cooling device 12, that is, at an upper portion thereof, and the inside thereof is communicated with a vertical passage 24 in the vertical cylinder 1 by a passage hole 23 formed in a peripheral wall of the vertical cylinder 1. I have. And the concentrate receiver 1
A concentrated liquid outlet 17a provided at the lower part of 7 is connected to the concentrated liquid tank 7 located below the concentrated liquid receiver 17 via a concentrated liquid return pipe 15. Reference numeral 21 denotes an on-off valve for opening and closing the concentrate return pipe 15.

Reference numeral 16 denotes an ice extraction port which is opened at a lower portion of the end of the horizontal cylinder 2. Below the ice extraction port 16, an ice receiving tank for receiving generated flake ice is provided.

During operation of the freeze-concentrator, the concentrate in the concentrate tank 7 is introduced into the vertical passage 24 from the concentrate inlet 1a of the vertical cylinder 1 through the concentrate pipe 14 by the circulation pump 8. Then, the concentrated liquid is pushed up in the vertical passage 24 by the circulation pump 8 and is taken away by the evaporation of the refrigerant in the cooling device 12 to be cooled.
By this cooling, the water in the concentrated liquid is frozen to form flake-like ice, which adheres to the inner wall surface of the vertical cylinder 1.

On the other hand, the cooling device 1 in the vertical passage 24
The scraping mechanism 3 provided at the inner portion of the rotary cylinder 2 is rotated by the motor 5, and the rotation causes the lower surface of the spiral blade 3b to scrape off the ice attached to the inner wall surface of the vertical cylinder 1 on the outer peripheral surface. The scraped flake-like ice fills the vertical passage 24 and is pushed upward while entering the horizontal passage 25.
Further, the ice in the lateral passage 25 is transported in the horizontal direction by the transport mechanism 4 driven by the motor 6, and
6 to the ice receiving tank 22.

The concentrated liquid whose concentration has been increased by the freezing and separation of water as described above flows down the inner wall surface of the vertical cylinder 1 and is stored in the concentrated liquid receiver 17 through the passage hole 23. This concentrate is returned to the concentrate tank 7 through the concentrate return pipe 15.
By repeating the above cycle, the concentrate tank 7
The concentration of water in the concentrate is reduced and the degree of concentration is increased.

[0013]

In the freeze-concentrating apparatus as shown in FIG. 3, the concentrated liquid introduced into the vertical passage 24 is conveyed upward through the vertical passage 24 by the cooling device 12. Although cooled, the flake-like ice conveyed to the lateral passage 25 after such a cooling process contains a large amount of concentrated liquid extract (fruit juice, etc.) attached to the surface layer in the upper cooling process. Tend to be. In such a freeze-concentrating apparatus, the ice to which the concentrated liquid extract adheres is supplied from the ice extraction port 16 to the ice receiving tank 2.
The occurrence of the problem that the concentrated liquid is lost by being discharged to 2 will be seen.

In view of the above-mentioned problems of the prior art, the present invention avoids adhesion of the extract of the concentrate to the frozen ice, in which the moisture in the concentrate generated during the cooling and freezing process of the concentrate is prevented. It is an object of the present invention to provide a freeze-concentrator capable of preventing the loss of water with ice and increasing the concentration of the concentrate.

[0015]

In order to solve the above-mentioned problems, the present invention is directed to a first aspect of the present invention, wherein a concentrated liquid contained in a concentrated liquid tank is transferred from a lower portion of a hollow vertical cylinder into the vertical cylinder. The concentrate is cooled from the outside of the vertical tube by a first heat exchanger, and the water in the concentrated solution is turned into flake-like ice. The ice is scraped by a scraping mechanism provided in the vertical tube. A freeze-concentrator for separating a concentrated liquid by transporting the concentrated liquid to increase the concentration of the concentrated liquid, wherein the first heat exchanger is provided downstream of the first heat exchanger in the vertical cylinder. A second heat exchanger for heating the cooled concentrated solution to a predetermined temperature in the exchanger is provided, and a concentrated solution return line for returning the concentrated solution after passing through the second heat exchanger to the concentrated solution tank is provided. Provided is a freeze concentration device characterized by being provided.

In the present invention, the second heat exchanger comprises:
Preferably, it is constituted by a coil wound around the outer periphery of the vertical cylinder and a heater for applying heating power to the coil.

According to a second aspect of the present invention, in the first aspect,
The vertical tube has a plurality of small holes through which a concentrated liquid flowing down the vertical tube can pass through a wall of a lower portion of the second heat exchanger, and the concentrated liquid passing through the small holes. To the concentrate return line.

According to a third aspect of the present invention, in the second aspect, a mesh such as a wire mesh is wound around the small hole, the outer periphery of the mesh is surrounded by the concentrated liquid passing through the mesh. Is provided, and an inlet end of the concentrate return line is connected to the concentrate receiver.

According to this invention, the concentrated liquid introduced into the vertical cylinder is cooled by evaporation of the refrigerant in the first heat exchanger, and flake-like ice is generated. This ice is scraped off by the scraping mechanism and transported. The flake-shaped ice contains a large amount of concentrated liquid adhering to the surface layer, and this ice is transported upward to reach the second heat exchanger, where the ice has a predetermined temperature. Heating up,
The temperature is raised. By such heating, the concentrated liquid adhering to the surface layer of the flake-shaped ice is separated, descends along the inner wall surface of the vertical cylinder, and passes through a small hole formed in the wall of the vertical cylinder, and the concentrated liquid return line. And returned to the concentrate tank.

Therefore, according to this invention, the flake-like ice to which the concentrated liquid generated in the first heat exchanger adheres is heated when passing through the second heat exchanger, and adheres to the ice. The concentrated liquid is separated and the concentrated liquid is recovered from the concentrated liquid return line to the concentrated liquid tank, so that the concentrated liquid is not lost together with the ice, and the concentration of the concentrated liquid can be efficiently increased.

If the net is provided as in the third aspect of the present invention, ice particles overflowing from the small holes can be captured by the net.
This ice can be prevented from entering the concentrate return line and diluting the concentrate.

Further, the invention described in claim 4 is the first invention.
In any one of the first to third aspects, a controller is provided for controlling the degree of cooling of the first heat exchanger and the degree of heating of the second heat exchanger.

In this case, the controller controls the degree of cooling of the concentrated liquid in the first heat exchanger and the degree of heating in the second heat exchanger based on a temperature detection signal such as the temperature inside the vertical cylinder. It is preferable that the temperature inside the vertical cylinder on the downstream side of the second heat exchanger of the vertical cylinder is controlled to a predetermined temperature.

According to this invention, by controlling the degree of cooling of the first heat exchanger and the degree of heating of the second heat exchanger by the controller, the temperature inside the vertical cylinder is conveyed through the vertical cylinder. The temperature at which the concentrated liquid adhering to the ice is completely separated can be controlled, and the concentration efficiency is improved.

Further, the first heat exchanger is an evaporator, and the second heat exchanger is a second heat exchanger.
It is also possible to configure a heat pump cycle by making the heat exchanger function as a condenser and connect it with a refrigerant circuit, and control the temperature inside the vertical cylinder to an appropriate temperature by controlling the temperature with a controller.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, and are merely illustrative examples. Only.

FIG. 1 is a configuration diagram of a freeze concentration device according to an embodiment of the present invention. In FIG. 1, reference numeral 1 denotes a vertically extending hollow vertical cylinder, 2 denotes a hollow horizontal cylinder connected to the upper end of the vertical cylinder 1 and extending in the horizontal direction. A vertical passage 24 for the concentrate is formed, and a horizontal passage 25 for transporting flake ice separated from the concentrate is formed inside the horizontal cylinder 2.

Reference numeral 3 denotes a scraping mechanism inserted into the vertical passage 24, and is formed by winding a spiral blade 3b around the center shaft 3a along the longitudinal direction. Reference numeral 4 denotes a transport mechanism inserted in the horizontal passage 25, and a spiral blade 4b is provided around the center shaft 4a.
Wrapped around. A motor 5 is connected to the lower end of the scraping mechanism 3 in the vertical cylinder 1 and drives the same. A motor 6 is connected to an end of the transport mechanism 4 in the horizontal cylinder 2 and drives the same.

Reference numeral 12 denotes a cooling device provided on the outer periphery of the lower part of the vertical cylinder 1. The cooling device 12 has a function of an evaporator of a refrigeration cycle, and is connected to a compressor 9 for compressing the refrigerant via refrigerant pipes 13 and 13 to condense the gas refrigerant compressed by the compressor 9. After that, it is led to the cooling device 12 via an expansion mechanism, and evaporated by the cooling device 12 to
The concentrated liquid introduced into the vertical passage 24 in the inside is cooled.

Reference numeral 7 denotes a concentrate tank for storing the concentrate.
A concentrated liquid pipe 14 having a circulation pump 8 is connected to the bottom opening of the tank 7. The other end of the concentrated liquid pipe 14 is connected to a concentrated liquid inlet 1a opened at the lower part of the front vertical cylinder 1.

Reference numeral 16 denotes an ice extraction port opened at the lower part of the end of the horizontal cylinder 2. Below the ice extraction port 16, an ice receiving tank 22 for receiving the generated flake ice is provided.

The above configuration is the same as the prior art shown in FIG. In the present invention, the vertical cylinder 1 is provided with a heating device for raising the temperature of the flake ice containing the concentrated liquid after passing through the cooling device 12 so as to control the temperature in the vertical passage 24.

That is, in FIG. 1, reference numeral 11 denotes a heating coil wound around the outer periphery of the vertical cylinder 1;
Is a heater for applying electric heat to the heater. The heating coil 11 is provided on the upper part of the vertical cylinder 1 and heats the concentrated liquid and flake ice cooled by the cooling device 12 to a predetermined temperature. Reference numeral 17 denotes a concentrate receiver provided on the outer periphery of the vertical cylinder 1. The concentrate receiver 17 is provided downstream, that is, above, the cooling device 12 and below the heating coil 11.

Reference numeral 17a denotes a concentrate outlet provided at the lower part of the concentrate receiver 17, which is connected to the concentrate tank 7 disposed below the concentrate receiver 17 via a concentrate return pipe 15. . Reference numeral 21 denotes an on-off valve for opening and closing the concentrate return pipe 15.

A number of small holes 18 are formed in a portion of the vertical cylinder 1 facing the concentrated liquid receiver 17, and a wire net 19 is provided in the concentrated liquid receiver 17 so as to surround the small holes 18. .

Reference numeral 30 denotes a controller, and 33 denotes the vertical cylinder 1
A temperature sensor 34 for detecting the temperature of the inner wall surface on the downstream side of the heater 10 is a detection line for transmitting a temperature detection signal from the temperature sensor 33 to the controller 30. The control output from the controller 30 is
2 and output to the heater 10 via a control line 31. The control output controls the capacity of the compressor 9 and the degree of heating of the heater 10.

During operation of the freeze-concentrator having such a configuration, the concentrated liquid in the concentrated liquid tank 7 passes through the concentrated liquid pipe 14 by the circulating pump 8, and the concentrated liquid inlet 1a of the vertical cylinder 1 is formed.
From the vertical passage 24.

The condensed liquid is pushed upward in the vertical passage 24 by the circulation pump 8 while being cooled.
At 2, the heat is removed by evaporation of the refrigerant and cooled. Such cooling freezes the water in the concentrate. By this cooling, the water in the concentrated liquid is frozen and becomes flake-like ice, which adheres to the inner wall surface of the vertical cylinder 1.

On the other hand, the cooling device 1 in the vertical passage 24
The scraping mechanism 3 provided at the inner part of the cylinder 2 is rotated by a motor 5, and the rotation scrapes off the ice adhered to the inner wall surface of the vertical cylinder 1 on the outer peripheral surface of the spiral blade 3b.

[0040] The flake ice thus produced contains a large amount of ice having a concentrated solution adhered to its surface as described above. The ice is filled up in the vertical passage 24 and is pushed upward by a pushing force of the circulation pump 8 or the like. When the ice reaches the inside of the heating coil 11, the ice is controlled by a controller 30 described later by electric heating of the heating coil. It is heated and heated to a predetermined temperature. By such heating, the concentrated liquid (the extract of the concentrated liquid) adhering to the surface layer of the flake ice is separated.

The separated concentrated liquid flows down along the inner wall surface of the vertical cylinder 1, flows out of the concentrated liquid receiver 17 through a number of small holes 18, and further passes through a wire mesh 19, thereby forming ice. One solid is captured, flows into the concentrated liquid return pipe 15 from the concentrated liquid outlet 17a, and is returned to the concentrated liquid tank 7 through the concentrated liquid return pipe 15.

Here, in the controller 30,
A detection signal of the temperature of the concentrated liquid downstream of the heating coil 11 in the vertical passage 24 detected by the temperature sensor 33 (the temperature of the inner wall of the vertical cylinder 1 is also possible), a detection signal of a discharge pressure of the compressor, and a power of the heater 10 , And the like. The controller 30 controls the capacity of the compressor 9 and the heating power of the heater 10 based on these signals to control the temperature of the wall surface of the vertical passage 24 to an appropriate temperature.

The cooling device 12 functions as an evaporator and the heating coil 11 functions as a condenser, and both are connected by a refrigerant circuit to form a heat pump cycle. The temperature control of the heat pump cycle is performed by the controller 30. The temperature in the cylinder 1 can be controlled to an appropriate temperature.

On the other hand, ice heated by the heating coil 11 to separate the concentrated liquid, that is, flake-shaped ice having no concentrated liquid adhered thereto, is transported upward in the vertical passage 24 and is moved horizontally in the horizontal cylinder 2. Enter the passage 25. Further, the ice in the lateral passage 24 is transported in the horizontal direction by the transport mechanism 4 driven by the motor 6, and sent out from the ice extraction port 16 to the ice receiving tank 22. By repeating the above cycle, the concentration of the concentrated liquid in the concentrated liquid tank 7 is reduced, and the concentration of the concentrated liquid is increased.

(Experimental Example) FIG. 2 shows the experimental results of the state of changes in the state of the concentrated liquid and ice for each operation time in the freeze-concentrating apparatus according to the present invention, and FIG. 2A shows the comparison result shown in FIG. In the case of technology, FIG. 2B shows the case of the embodiment shown in FIG.

As is clear from FIG. 2, the ice phase concentration, that is, the degree to which the ice extracted from the ice extraction port 16 contains the concentrated liquid is 150 minutes in the comparative technique (FIG. 2A). 6.9%, whereas in the embodiment of the present invention, the operation time was 140 minutes and 0.54%, which is about 1/12 of the prior art. That is, in the apparatus of the embodiment of the present invention shown in FIG. 1, the amount of the concentrate contained in the ice extracted after the freeze-concentration step, that is, the amount of the concentrate lost together with water is 1 / the amount of the prior art. It has decreased to about 12.

[0047]

As described above, according to the present invention, the flake-like ice to which the concentrated liquid is generated, which is generated in the first heat exchanger, is heated in the second heat exchanger. The concentrated liquid adhering to the surface layer of the ice can be reliably separated and collected in the concentrated liquid tank, so that the concentrated liquid can be prevented from being lost together with the ice. Thereby, the concentration of the concentrated liquid can be efficiently increased.

In particular, according to the present invention, the controller controls the degree of cooling of the first heat exchanger and the degree of heating of the second heat exchanger, thereby concentrating the temperature inside the vertical cylinder from ice. The temperature can be controlled to an appropriate temperature at which the liquid is separated, and the concentration efficiency is improved.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a freeze concentration device according to an embodiment of the present invention.

FIG. 2 is a comparison table of the freezing performance of the device of the embodiment and the conventional technology.

FIG. 3 is a diagram corresponding to FIG. 1 showing a comparative technique with the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 vertical cylinder 2 horizontal cylinder 3 scraping mechanism 4 transport mechanism 5, 6 motor 7 concentrated liquid tank 8 circulation pump 9 compressor 10 heater 11 heating coil 12 cooling device 13 refrigerant pipe 14 concentrated liquid pipe 15 concentrated liquid return pipe 16 ice extraction Mouth 17 Concentrate receiver 18 Small hole 19 Wire mesh 21 On-off valve 22 Ice receiver tank 24 Vertical passage 25 Horizontal passage 30 Controller 33 Temperature sensor

Continued on the front page (72) Inventor Shigeru Sakashita 2-13-1, Botan, Koto-ku, Tokyo Inside Maekawa Manufacturing Co., Ltd.

Claims (4)

[Claims] 1. A concentrated liquid contained in a concentrated liquid tank is injected into the vertical cylinder from the lower part of a hollow vertical cylinder, and cooled by a first heat exchanger from outside the vertical cylinder to form the concentrated liquid. The concentrated water is flaked ice, and the concentrated liquid is separated by scraping and transporting the ice by a scraping mechanism provided in the vertical cylinder, and freeze concentration is performed so as to increase the concentration of the concentrated liquid. In the apparatus, on the downstream side of the first heat exchanger of the vertical cylinder, a second liquid for heating the concentrated liquid cooled by the first heat exchanger to a predetermined temperature.
And a concentrated liquid return line for returning the concentrated liquid having passed through the second heat exchanger to the concentrated liquid tank. 2. The vertical cylinder has a plurality of small holes, through which a concentrated liquid flowing down the vertical cylinder can pass, formed in a wall of a lower portion of the second heat exchanger. 2. The freeze concentration device according to claim 1, wherein the concentrate is passed through the hole to guide the concentrate to the concentrate return line. 3. A net, such as a wire net, is wound around the small hole, and a concentrate receiver for containing a concentrate passed through the net is provided around the outside of the net, and the concentrate receiver is provided. 3. The freeze-concentrator according to claim 2, wherein an inlet end of the concentrated liquid return line is connected to the concentrated liquid return line. 4. The freeze concentration apparatus according to claim 1, further comprising a controller that controls cooling of the first heat exchanger and heating of the second heat exchanger.