JP2002071247A - Method and system for producing ice containing salt - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce healthy ice containing salt uniformly with high efficiency without using a refrigerating machine utilizing condensation/evaporation of refrigerant, e.g. CFC. SOLUTION: Ice containing salt is produced by spraying saline water into low temperature air flow to generate nuclei of ice in the low temperature air flow, floating the nuclei of ice in the low temperature air flow until they grow up or join to produce ice particles containing salt and then separating the ice particles containing salt from the air flow and collecting them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for producing salted ice suitable for storing marine fish and shellfish.

[0002]

2. Description of the Related Art During transportation or storage of marine fish and shellfish, freshness is maintained by coexisting ice.
When freshwater ice is used for marine fish and shellfish, freshwater penetrates from gills and epidermis and freshness is reduced. Therefore, it is desirable to use salted ice containing salt similar to seawater.

[0003] Even if seawater itself is frozen in order to obtain salt-containing ice, the solubility of salts differs between solid and liquid, so that the ice does not usually have the same composition as seawater. In other words, even if ice is produced using seawater as a raw material in the same manner as freshwater, the salt that precipitates between the particles is pushed out to the outside when the water molecules gradually bind and solidify. Become. There is also a problem in terms of hygiene when using seawater as a raw material. Therefore, it has been proposed to produce fresh water ice once using fresh water, add an appropriate amount of salt to the ice, and freeze the ice. For example, JP-A-1-184375 and JP-B-6-6-6
Japanese Patent No. 3678 discloses a method of producing flaked or powdered / granular freshwater ice from freshwater, adding or spraying saltwater having an adjusted concentration to the freshwater ice, stirring and mixing under cooling conditions, and press forming. An apparatus for producing salt water ice is disclosed.

An attempt to produce salt water ice directly from seawater is disclosed in, for example, Japanese Patent Application Laid-Open No. 5-25647.
As disclosed in Japanese Patent Application Laid-Open Publication No. H10-209, there is known an apparatus in which cooled seawater is sprayed into a vacuum (decompression) vessel, and the waterdrop is rapidly cooled by latent heat when the waterdrop evaporates to produce ice.

[0005]

According to the former method, flake-like or powdery / granular fresh water ice is produced and then mixed with salt water under cooling conditions to re-freeze the ice.
Since the steps are performed separately, the man-hours increase and the management becomes complicated, and depending on the method of stirring and mixing the fresh water ice and the salt water, the salt concentration in the salt-containing ice may not be uniform, and a concentration difference may occur. There is. In addition, a refrigerator for ice making is required, and the equipment must be large-scale. Refrigerators utilizing condensation and evaporation of refrigerants such as chlorofluorocarbon also have environmental problems.

On the other hand, in the method of spraying salt water in a vacuum,
Since the water is removed by evaporation, the salt concentration in the produced ice increases, and the solidification rate of the water decreases, so that the ice making efficiency is poor and the equipment and operation are not practical.

Accordingly, an object of the present invention is to solve such a problem and to provide a method and an apparatus for producing salted ice efficiently and at low cost.

[0008]

According to the present invention, ice nuclei are formed in a low temperature air stream, preferably in a rising air stream of low temperature air, by spraying salt water. Suspended in the low-temperature air flow until the particles grow or bond to salt-containing ice particles, and then separate and collect the salt-containing ice particles from the air flow, preferably, separate and collect them by gravity by gravity. A method for producing ice is provided.

Further, according to the present invention, a spray tower having an air outlet below and an air outlet above and having a spray nozzle in the upper part of the tower, and a low-temperature air producing apparatus for producing a low-temperature air flow An air conduit for guiding the low-temperature air produced by the low-temperature air producing device to an air outlet of the spray tower;
The apparatus for producing salted ice, comprising: a primary compressor, a primary cooler, a secondary compressor, a secondary cooler, an air-to-air heat exchanger, and an air-to-air heat exchanger in the order of air flow. Provided is an apparatus for producing salt ice, which is connected to an expander.

This apparatus for producing salted ice has an ice particle receiving portion at the bottom of the spray tower, one end of which is connected to the ice particle receiving portion, and the other end of which is inside a container (ice storage) outside the tower. A means for transferring ice particles, such as a screw conveyor, connected to the ice press, and an ice press installed in a container outside the tower, and a discharge end of the transfer means connected to the ice press. Is done. In addition, the low-temperature air producing device is
It has an air sampling port to the inside of the machine and an air outlet from the inside of the machine. The air sampling port is connected to the outside air inlet through a HEPA filter and is also connected to the air outlet of the spray tower. It is connected to the air outlet of the tower.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have made various prototypes in order to solve the above-mentioned problems. It is presumed that when sprayed, the salt water mist immediately floats as salt-containing ice nuclei, and if these ice nuclei are properly floated in the low-temperature air, they will bond to each other. , Salt-containing ice particles containing large salt,
Typically, it has been found that the particles grow to salt-containing ice particles having an average diameter of about 5 mm. The ice particles contain salt at substantially the same concentration as the salt water. That is, it is substantially prevented that only the salt becomes solid and precipitated salt particles are generated as in the case of vacuum evaporation.

As described above, in order to generate salt-containing ice particles by spraying with salt water, it is necessary that the salt-containing mist floats properly in the low-temperature air. Airflow is required. To create this airflow,
Preferably, a flow of air having a pressure of at least 90 KPa is formed. Most preferably, 90 KP in the spray tower
It is preferable to form an upward flow of a continuous flow of air having a temperature equal to or higher than a and equal to or lower than -10 ° C, and spraying the upward flow with brine. That is, when the salt-containing mist is suspended in a flowing state in the rising flow of low-temperature air, they are joined to each other and grow into salt-containing ice particles containing salt, and the particle size increases. Fall naturally. The wind speed in this case is 6m /
More than sec, in practice, it is preferably about 10 to 15 m / sec. If salt water is sprayed in a vacuum or reduced-pressure atmosphere where no air flow exists as proposed in Japanese Patent Application Laid-Open No. 5-25647, water in the salt water evaporates immediately into the atmosphere, and Since the phenomenon of mist floating does not occur, it is considered that ice particles hardly grow.

[0013] At 90 KPa or more, minus 10
In order to form a low-temperature air flow of not more than 0 ° C., preferably not more than −20 ° C., it is preferable that the continuously taken air is sequentially compressed, cooled and expanded to change into such a low-temperature air flow. In a method of indirectly producing low-temperature air using a normal refrigerator using a condensation / evaporation cycle of a refrigerant such as chlorofluorocarbon, it is difficult to efficiently create an air flow of -10 ° C or less, and even 20 ° C or less. , Heat and power consumption are also wasted.

Hereinafter, embodiments of the present invention shown in the drawings will be described.

FIG. 1 shows an example of an apparatus for carrying out the method of the present invention. The apparatus for producing salted ice shown in the figure comprises a spray tower 1, a low-temperature air producing apparatus 2, and a press machine for salted ice. The low-temperature air produced by the low-temperature air producing device 2 is sent to the spray tower 1 through the air line 4 and
The salt-containing ice particles generated in the spray tower are sent to the press 3 by the screw conveyor 5.

The spray tower 1 has an air outlet 6 in the lower part of the tower and an air outlet 7 in the upper part, and a spray nozzle 8 is installed in the upper part of the tower. One end of the screw conveyor 5 is hermetically inserted into the salt ice particle receiving portion 9 at the bottom of the tower.

Salt water is supplied to the spray nozzle 8. The salt water is produced by adding a required amount of salt to fresh water (tap water) in a water tank 10. Seawater can be used, but in this case, it is filtered, sterilized (sterilized), deodorized, and stored in the water tank 10. In the apparatus shown in the figure, in order to assist the spraying of salt water in the spray nozzle 8, an ultrasonic wave is applied to the salt water by using an ultrasonic vibration device 11 to spray the salt water. Reference numeral 12 denotes a salt water pump.

The air outlet 6 is provided at a predetermined distance from the spray nozzle 8 with the discharge port facing upward so that the low-temperature air blown from the air outlet rises uniformly in the tower. When the salt water is sprayed toward this upward flow of air, the sprayed salt water mist floats on this upward flow, and has a large diameter during floating in the low-temperature air. Ice particles, and the larger the particles grow, the lower the particles against the upward flow and fall into the salt-containing ice particle receiving portion 9 at the bottom of the tower. Although not shown, an eliminator for collecting mist can be provided between the spray nozzle 8 and the air outlet 7.

In this manner, 90
An ascending flow of low-temperature air of not less than KPa and not more than -10 ° C. is continuously formed, and the continuous flow of the low-temperature air is supplied from the low-temperature air producing device 2 through the pipe 4 to the air outlet 6.
Supplied to

The low-temperature air producing apparatus 2 includes a primary compressor 14 connected to a power source (motor in the illustrated example) 13. The compressed air obtained by the primary compressor 14 is converted into a primary cooler 15. , A secondary compressor 16, a secondary cooler 17, an air-to-air heat exchanger 18, and an expander 19 in order to continuously produce low-temperature air. The primary compressor 14 can use a motor-driven booster. The primary cooler 15 and the secondary cooler 17 can use an air-water heat exchanger that exchanges heat with the cooling water. Secondary compressor
16 and the expander 19 can utilize an integrated air compression and expansion device that rotates coaxially. As the air-to-air heat exchanger 18, a cross-flow type using a resin material as a heat transfer plate can be used.

Now, the primary compressor 14 is set to 30 at 100 KPa.
A description will be given of the state of air treatment in each device when a low-temperature air flow of 100 KPa minus 55 ° C. is produced by taking in air at a temperature of 140 KPa · 65 ° C. in the primary compressor 14. Use high pressure and high temperature air. This air is heat-exchanged with cooling water in a primary cooler 15 to
0KPa ・ 40 ℃, and the secondary compressor 16
High pressure and high temperature air of 80 KPa and 70 ° C. This high-pressure high-temperature air is cooled by cooling water in the secondary
0 KPa · 40 ° C., and in the air-to-air heat exchanger 18, minus 3 returning from the spray tower 1
180 KP by heat exchange with return air at 0 ° C
a. High-pressure low-temperature air of minus 20 ° C, which is an expander
100 KPa by sending to 19 and adiabatic expansion
Obtain a low temperature air flow of minus 55 ° C.

This low-temperature air flow of 100 KPa minus 55 ° C. is supplied through line 4 into the spray tower 1 and used to produce salted ice particles from the salt water sprayed from the spray nozzle 8. Air outlet 7 and exhaust pipe
After passing through 20, the air becomes 100 KPa · −30 ° C. and enters the air-to-air heat exchanger 18 of the low-temperature air producing apparatus 2, where the air (180 KPa · 40
C), and returns to the primary compressor 14 as air at 30 ° C. at 100 KPa. "In" in the figure indicates an air sampling port for the low-temperature air producing apparatus, and this air sampling port (I
n) is connected to an exhaust line 20 from the spray tower.
Further, “Out” in the figure is an air outlet for taking out low-temperature air from the low-temperature air producing device, and this air outlet (Out) is connected to the air outlet 6 of the spray tower via the air line 4.

In this example, the low-temperature air producing device 2 and the spray tower 1 are connected in a closed air system to form a closed system, and a low-temperature air flow of 100 KPa minus 55 ° C. is continuously supplied to the spray tower 1. , 100 from spray tower 1
Although it returns to the low-temperature air producing device 2 as KPa · −30 ° C. air, it is used to supplement the air flowing out of the system during operation or to charge the air when starting the device. Therefore, when introducing the outside air into the system, the outside air line is connected to the line leading to the air sampling port (In), and the HEPA filter 22 is attached to the outside air inlet 21, and the dust in the atmosphere is installed. It is desirable to prevent bacteria and bacteria from entering the system.

When the salt water is sprayed into the cryogenic air stream at substantially normal pressure, the salt water mist instantaneously changes into an ice nucleus, and this ice nucleus (fine ice powder having a size of 1 to 2 mm or less) is formed.・
(Similar to stardust) floats in this upward flow of air for a predetermined period of time, and aggregates or joins with each other to grow into salt-containing ice particles containing salt. And store. Next, the treatment of the collected salted ice particles will be described.

An ice storage 23 as an airtight container is provided near the outside of the spray tower 1, and an ice press machine 3 is installed in the middle of the ice storage 23. Ice press 3
Consists of a cylinder 24 and a piston 25,
This is a reciprocating press in which an opening / closing door 26 is provided on the cylinder wall on the opposite side. A screw conveyor 5 is air-tightly suspended between the ice press machine 3 and a receiving portion 9 at the bottom of the spray tower, and the salt-contained ice particles accumulated in the receiving portion 9 by driving the screw conveyor 5 are ice-pressed. It is fed into a cylinder 24 in the machine 3. That is, an airtight space is formed between the spray tower 1 and the cylinder 24 of the ice press by an outer cylinder of a screw conveyor, and a screw is arranged in the outer cylinder to receive the salt-containing ice particles in the receiving portion 9 and to receive the ice-containing particles. Can be fed into the cylinder 24 from the discharge end of the screw conveyor. When the salt-containing ice particles are fed into the cylinder 24, the opening / closing door 26 is opened. When the salt-containing ice particles are filled in the cylinder 24, the door 26 is closed and the piston 25 presses the salt-containing ice particles. The pressed product is dropped from the inside of the cylinder 24 to the storage portion at the bottom of the ice storage 23 by opening the on-off valve 27 provided at the bottom of the cylinder 24.

The ice storage 23 as well as the press 3
The inside of the screw conveyor 5 and the inside of the screw conveyor 5 must also be maintained at a sufficiently low temperature not higher than the melting point of salted ice, but this low temperature is maintained by the opening 28 provided at the upper part of the spray tower 1 and the upper part of the ice storage 23. The opening 29 may be connected to a duct 31 interposed with a blower 30, and a part of the low-temperature air that has passed through the spray tower 1 may be sent into the ice storage 23 by driving the blower 30. Since the ice press 3 is installed in the ice storage 23 and the screw press 5 is hermetically connected between the ice press 3 and the receiving portion 9 at the bottom of the spray tower, low-temperature air circulates inside. And maintained at a sufficiently low temperature.

As described above, according to the equipment of FIG. 1, salt-containing ice particles can be efficiently and continuously produced. However, the equipment comprising the spray tower 1 and the low-temperature air production apparatus 2 of FIG. As a further application, it can be applied to flash freezing of foods and pharmaceuticals. That is, when liquid foods and pharmaceuticals are flash-frozen into particles, this equipment allows minerals, necessary nutrients, and the like in the liquid to remain in the particles at a high yield. In this case, the temperature and wind speed of the low-temperature air supplied to the spray tower may be appropriately controlled according to the type and amount of the processed product, and the obtained solid particles are also classified into necessary products by a method other than pressing. It is also possible.

[0028]

According to the present invention, fine salt-containing ice nuclei are generated by discharging salt water in a cryogenic air stream in a mist state, and these are aggregated together to confine salt therein. To obtain salty ice particles with a large particle size.
Salt-containing ice containing salt uniformly can be produced. Then, by pressing the salt-containing ice particles, a pressed product of salt-containing ice, which also contains salt uniformly, is obtained. And
By producing the low-temperature air by compressing, cooling and adiabatic expansion of the air, a continuous and sterile low-temperature air flow can be obtained, so that sanitary salt-containing ice can be produced efficiently and at low cost. be able to. For this reason, salt ice can be produced not only on land but also on ships as well as on sea, and it can be used not only to maintain the freshness of seafood during storage and transportation, but also to maintain the freshness in pelagic fisheries. Can greatly contribute.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of an apparatus for producing salted ice according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spray tower 2 Low-temperature air production apparatus 3 Press machine 4 Air line 5 Screw conveyor 6 Air outlet 7 Air outlet 8 Spray nozzle 9 Receiving part 14 Primary compressor 15 Primary cooler 16 Secondary compressor 17 Secondary cooler 18 Air-to-air heat exchanger 19 Expander 23 Ice storage In Air inlet to cryogenic air generator Out Air outlet from cryogenic air generator

Claims (7)

[Claims] 1. A method of spraying salt water into a stream of cold air to generate ice nuclei in the stream of cold air, suspending the ice nuclei in the stream of cold ice until the ice nuclei grow or join to salt-containing ice particles, Then, a method for producing salted ice, wherein the salted ice particles are separated and collected from an air stream. 2. The low-temperature air stream has a pressure of 90 KPa or more and a temperature of -10 ° C. or less, and the salt-containing ice particles having an average particle diameter of 1 mm or more are naturally dropped by their own weight and separated and collected from the air stream. Item 10. The method for producing salted ice according to Item 1. 3. A spray tower having an air outlet below and an air outlet above and having a spray nozzle for spraying salt water in the upper part of the tower, and a low-temperature air for producing a low-temperature low-temperature air stream. An apparatus for producing salt ice, comprising: a production apparatus; and an air conduit for guiding the low-temperature air produced by the low-temperature air production apparatus to an air outlet of the spray tower. 4. The low-temperature air producing apparatus is constructed by connecting a primary compressor, a primary cooler, a secondary compressor, a secondary cooler, an air-to-air heat exchanger, and an expander in the order of air flow. The apparatus for producing salted ice according to claim 3. 5. The spray tower has an ice particle receiving portion at the bottom thereof, one end of which is connected to the ice particle receiving portion and the other end of which is connected to a container outside the tower. The apparatus for producing salted ice according to claim 3 or 4, further comprising: 6. The apparatus for producing salted ice according to claim 5, wherein an ice press is installed in a container outside the tower, and the discharge end of the transfer means is connected to the ice press. 7. The low-temperature air producing apparatus has an air sampling port and an air outlet, and the air sampling port is connected to an outside air inlet via a HEPA filter and to an air outlet of a spray tower. The apparatus for producing salted ice according to claim 4, wherein the air outlet is connected to an air outlet of the spray tower via an air pipe.