JPS6336828A - Production of dried particulate material and vacuum freeze dryer - Google Patents

Abstract

PURPOSE:To efficiently obtain a dried product at a small quantity of energy by subjecting the aq. soln. of a raw material to be irradiated with far infrared rays under reduced pressure to concentrate it and thereafter icing and freezing it to form a particulate material to be dried and then projecting far infrared rays thereon under vacuum to freeze-dry it. CONSTITUTION:The inside of a concentration tank 11 is maintained at reduced pressure by actuating a decompression device 17, and a raw liquid A is fed to the tray 25 of an uppermost step provided in the concentration tank 11. Far infrared rays radiators 30 are simultaneously heated and while the raw liquid A naturally falls down in multiple trays 25, it is irradiated with far infrared rays. Thereby the water content incorporated in the raw liquid A is evaporated to concentrate it. The concentrated raw liquid A is fed into an ice making machinery 40, frozen and iced and made to a particulate material B to be dried. Then the inside of a vacuum tank 51 is maintained at vacuum by actuating a vacuum exhauster 57 and the frozen particulate material B to be dried is fed to the uppermost conveyor 63 by actuating the conveyor 63. While this particulate material B to be dried is carried by the conveyor 63, it is projected with the far infrared rays fed from far infrared radiators 64, and the water content of the inside is efficiently sublimed and a dried particulate material C is obtained.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing dried granular or powdered products from aqueous solutions of pharmaceuticals, foods, chemicals, etc., and a vacuum freeze-drying apparatus used to carry out the method. Regarding.

This kind of granular dried product manufacturing method and vacuum freeze-drying equipment are:
For example, in the field of obtaining dried granules or powder from an aqueous solution of bacterial cells that are easily killed by heat, such as lactic acid bacteria and bifidobacteria, or in the field of obtaining granules or powder from an aqueous solution of geothermally sensitive enzymes such as boulothiase and lipase. Fields in which dried products of granules or powders are obtained from aqueous solutions of pharmaceuticals or chemicals such as antibiotics, herbal medicines, physiologically active substances, vitamins, amino acids, etc., or seasonings. ,
It can be used in the field of obtaining granular or powdered dried products from aqueous solutions of foods such as fruit juices, sweeteners, beverages, dairy products, and various extracts.

[Prior art]

Conventionally, as a method and apparatus for obtaining granular or powdery dried products from the various aqueous solutions described above, a method and an apparatus have been used in which the aqueous solution is directly freeze-dried in a vacuum chamber. As a heating method for drying in a vacuum chamber, a method that performs conduction heating or radiation heating using a heating shelf in which a heating medium such as heated oil, hot water, steam, etc. is circulated is generally adopted. It had been.

[Problem that the invention seeks to solve]

In the case of the conventional drying method and apparatus described above, since a large amount of water in an aqueous solution is directly frozen, a large amount of water needs to be sublimated, a large amount of energy is required, and the drying process takes a long time. It had become. Furthermore, in the conventional heating method described above, the temperature distribution on the heating shelf tends to be uneven due to the circulation structure of the heating medium, etc., and there is a possibility that the dried product may be dried unevenly.

[Means for solving problems]

In view of the above-mentioned problems, an object of the present invention is to provide a method for efficiently producing a high-quality dried product in the form of granules or powder from an aqueous raw material, and a vacuum freeze-drying apparatus used to carry out the method.

According to the present invention, there are a step of concentrating the aqueous solution raw material by irradiating the aqueous solution raw material with far infrared rays in a depressurized concentration tank, and a step of forming and freezing the concentrated raw material to produce a frozen granular dried material. Provided is a method for producing a granular dried product, which comprises a step of sublimating moisture in the granular dried material by irradiating the frozen granular dried material with far infrared rays in a vacuum chamber to dry it.

Further, according to the present invention, there is provided a vacuum freeze-drying apparatus for use in carrying out the method for producing dried granular products, comprising: a vacuum chamber; and an evacuation device connected to the vacuum chamber to evacuate the inside of the vacuum chamber. means, a cold trap device for condensing and collecting moisture in the exhaust gas, a drying material supply means for supplying the frozen granular material to be dried into the vacuum chamber, and a frozen granular material in the vacuum device. A vacuum freeze-drying apparatus is provided that includes far-infrared ray irradiation means for irradiating far-infrared rays onto a material to be dried.

[For production]

Generally, when removing the same amount of water from an aqueous raw material, concentration under reduced pressure requires less heat than freeze-drying under vacuum. In the present invention, the aqueous raw material is concentrated under reduced pressure and the concentrated liquid or slurry raw material is freeze-dried under vacuum, so the amount of water to be sublimed can be reduced, and the amount of water required to produce the dried product can be reduced. This results in total energy savings.

Moreover, in the concentration step, the aqueous solution raw material in the concentration tank is heated by radiant heating using far infrared rays, so it is possible to supply energy efficiently and to save energy in the concentration step. Furthermore, in the drying process, since the frozen material to be dried is granular, the heat receiving surface area, that is, the sublimation surface area, of the material to be dried in the vacuum chamber increases, making it possible to shorten the drying time. In addition, the moisture inside the material to be dried easily sublimates (because it becomes
Uneven drying is less likely to occur, and a high quality dried product can be obtained. Moreover, since the material to be dried is heated and dried in the vacuum chamber by radiation heating using far infrared rays, it is possible to supply energy efficiently and to save energy in the drying process.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of the overall configuration in which a far-infrared heating type vacuum concentration device 10, an ice maker 40, and a vacuum freeze-drying device 50 are connected to each other for carrying out the method for producing granular dried products according to the present invention.

Introduction Far-infrared heating type vacuum concentrator lO shown in Figure 1
To explain the first configuration example, the far infrared heating type vacuum concentration device is equipped with a concentration tank 11 that can withstand reduced pressure, and the concentration tank 11 is connected to a condenser 14 via a pressure reduction pipe 12 equipped with an exhaust valve 13 in the middle. is connected to. The condenser 14 has a condensing pipe 1 cooled by a refrigerant from a condensing cooling device 15.
4a is provided, and the water vapor generated in the concentrating tank 11 is condensed by this condensing pipe 14a. The condenser 14 is connected to a pressure reducing device 1 such as a vacuum pump through a pressure reducing pipe 16.
It is connected to 7. The pressure reducing device 17 has the ability to maintain the degree of vacuum inside the concentration tank 11 at, for example, 10 to 100 Torr.

A stock solution piping 18 for supplying an aqueous solution raw material, that is, a stock solution A into the concentration tank 11 is connected to the concentration tank 11 , and the stock solution pipe 18 is connected to a stock solution tank 20 via a stock solution supply pump 19 . Further, in order to discharge the stock solution A concentrated to a predetermined concentration to the outside of the concentration tank 11, the concentration tank 11 is connected to the concentrated liquid tank 24 via the storage chamber 21 and discharge switching valves 22, 23 before and after the storage chamber 21. There is. By alternately opening and closing the switching valves 22 and 23? It is possible to take out the concentrated stock solution A in liquid or slurry form to the outside of the concentration tank 11 while preventing a decrease in the degree of vacuum in the concentration tank 11.

What's inside the concentration tank 11? ; A plurality of trays 25 (six in the configuration example shown) for allowing the stock solution A supplied into the contraction tank 11 to flow down by gravity are arranged in multiple stages in the vertical direction. 1
The stock solution A is supplied from the stock solution pipe 18 to the tray 25 at the top stage.

The tray 25 has the form of a dish-shaped container with a large upward opening. Note that the number of stages of the trays 25 can be appropriately selected depending on the processing amount of the stock solution, the required amount of evaporation, and the like.

In order to keep the liquid depth of the stock solution A constant in the tray 25 against the weight loss of the stock solution A due to evaporation of water while flowing down the tray 25, the liquid solution A is placed at least in the second stage from the top (in the illustrated configuration example, the fourth stage). ) is provided with a circulation device 26 that circulates the stock solution A from the tray 25 of the tray 25 to the first tray 25. In the illustrated configuration example, a combination of a circulating fluid pump 27 and a circulating fluid piping 28 is used as the circulation device 26.

Further, in the illustrated configuration example, a vibration conveyance device 29 is provided on the tray 25 below the tray 25 from which the circulating fluid is extracted. The vibration conveying device 29 plays the role of forcibly causing the slurry concentrated stock solution A in the tray 25 or the crystals precipitated from the concentrated stock solution A to flow down by applying vibrations to the tray 25. The tray 25 to be provided with the vibration conveyance device 29 can be appropriately selected depending on the degree of slurryization of the stock solution A, etc.

A far-infrared radiator 30 is disposed above the tray 25 to heat the stock solution A in the tray 25 by irradiating it with far-infrared rays. In the illustrated configuration example, the far-infrared radiator 30 has a rod-like shape, but it is also possible to use a plate-like, lamp-like, or other shape, and these various shapes of the far-infrared radiator 30 can be used in combination as appropriate. You can also. When using the rod-shaped or lamp-shaped far-infrared radiator 30, a far-infrared reflector 31 can be used.

In the illustrated configuration example, a plurality of rod-shaped far-infrared radiators 30 are arranged parallel to the lower surface of the undiluted solution flow of the tray 25 and parallel to the flow direction of the undiluted solution A at intervals. Reflector 31 so as to cover almost the upper half of 30
is installed.

The far infrared rays reflected by the reflector 31 are reflected by the undiluted solution A in the tray 25.
irradiated onto the surface of

Although illustration of the internal structure is omitted, the far-infrared radiator 3
0 has an outer shell housing a heating source inside. The outer shell can be made of ceramic, but it may also have a structure in which a ceramic spray coating film is formed on the outer surface of a metal outer shell.

The ceramic used for the far-infrared radiator 30 may be any one or two of aluminum, magnesium, chromium, silicon, zirconium, beryllium, lithium, titanium, vanadium, iron, cobalt, nickel, antimony, and tin. It can be more than one oxide.

As a heating source, that is, a primary heating element for the far-infrared radiator 30, an electric heater such as a nichrome wire heater, steam, combustion gas, etc. can be used, but leakage of the heating source due to deterioration of the outer shell of the radiator 30 can be In order to prevent this and improve the accuracy of temperature control, an electric heater is used in the illustrated configuration example.

It is desirable that the liquid temperature of the stock solution A in the tray 25 be maintained at a temperature slightly lower than the saturation temperature at which the degree of vacuum in the concentration tank 11 is the saturated vapor pressure, for example, 10 to 50°C. For this purpose, in the illustrated configuration example, the surface temperature of the far-infrared radiator 30 is detected by each sensor 33, and the far-infrared radiator 30 is
A temperature control device 32 is connected to the far-infrared radiator 30 to control the thermal load (here, the current supplied to the electric heater). Here, the temperature of all the far-infrared radiators 30 is controlled based on temperature detection by a single sensor 33, but the surface temperature of the far-infrared radiators 30 at each stage is controlled by a plurality of sensors. The temperature of the far-infrared radiator 30 may be controlled for each stage.

When concentrating stock solution A under reduced pressure using the far-infrared heating type vacuum concentrator having the above configuration, first, the condensing cooling device 1
5 is activated, and the pressure reduction device 17 is activated to maintain the inside of the concentration tank 11 at a vacuum level of, for example, 60 Torr.

Next, the stock solution supply pump 19 is operated, and the stock solution A in the stock solution tank 20 is supplied by the pump 19 to the uppermost tray 25 in the fQ condensation tank II. Simultaneously with supplying the stock solution, the far-infrared radiator 30 generates heat, and the circulating fluid pump 27 and the vibration conveying device 29 are activated.

The far-infrared radiator 30 is controlled by a temperature control device 32 so that the raw solution in the tray 25 is maintained at a temperature of 40° C., for example.

While the stock solution A is flowing down the multi-stage tray 25,
The stock solution A is irradiated with far-infrared rays effective for evaporating water from the far-infrared radiator 30. As a result, the water in the stock solution A evaporates and the stock solution A is concentrated.

The moisture evaporated from the stock solution A is condensed by the condenser 14. A portion of the stock solution is circulated by the circulating N liquid pump 27.

The concentrated stock solution A is stored in the concentrated solution tank 24 through the storage chamber 21 and the discharge switching valves 22, 23 before and after the storage chamber 21.

According to the working conditions as exemplified above, for example, a solution containing various amino acids (concentration 3 wt%) is heated at 40β/Hr.
10vo1% (amino acid concentration 3
It was confirmed that the volume could be reduced to 0wt%) and that a concentrate with good quality could be obtained. The resulting concentrate has excellent stability,
Long-term storage is possible.

Figures 2 and 3 show the second part of the far-infrared heating vacuum concentrator.
This shows a configuration example. In these figures, the first
Components similar to those in the configuration example are given the same reference numerals. In this second configuration example, as shown in detail in FIG.
A far-infrared reflector 31 is provided only for the far-infrared ray emitter 30 above the tray 25 in the uppermost stage. As the ceramic used for the tray 25, the same material as the ceramic for the far-infrared radiator 30 described above can be used.

Therefore, the stock solution A in the second and subsequent trays 25 is not only irradiated with far-infrared rays from the far-infrared radiator 30 above it, but also is irradiated with heat from the far-infrared radiator 30 below the tray 25. The body becomes a far-infrared ray emitter due to the ceramic coating film 25a, and irradiates the stock solution A in the tray 25 with far-infrared rays. Therefore, the stock solution A in the tray 25 can be concentrated even more efficiently. In addition,
In this configuration example, the portions not shown in FIG. 2 have the same configuration as the first configuration example, and are omitted for simplicity of the drawing.

FIG. 4 shows a third configuration example of a far-infrared heating type vacuum concentrator. In this figure, the same reference numerals are attached to the same components as in the first configuration example. In this configuration example, a temperature control device 32 detects the liquid temperature of the stock solution A supplied into the concentration tank 11 using, for example, a sensor 33 provided in the middle of the circulating fluid piping 28 and controls the heat load caused by the far-infrared radiator 30. is connected to the far-infrared radiator 30. In this configuration example, the parts not shown in FIG. 4 have the same configuration as the first configuration example, and M
Illustrations are omitted for the sake of adjustment.

This configuration example also provides the same effects as the first configuration example.

Referring again to FIG. 1, concentrated liquid or slurry stock solution A is supplied into the ice making machine 40 by a concentrated solution supply pump 41. As shown in FIG. The ice maker 40 has the ability to make ice by freezing liquid or slurry undiluted solution at a temperature of, for example, -40°C to -10°C. The liquid or slurry stock solution A is frozen and made into ice by the ice maker 40 to become a granular material to be dried B.

Next, the configuration of the vacuum freeze-drying apparatus 50 shown in FIG. 1 will be explained.

The vacuum freeze-drying apparatus 50 includes a vacuum chamber 51 , and a cold trap 53 is connected to the vacuum chamber 51 via an exhaust valve 52 . A refrigerator 54 is installed in the cold trap 53.
A condensing coil 55 is disposed which is cooled by a refrigerant from. The refrigerator 54 has the ability to maintain the surface temperature of the condensing coil 55 at, for example, -50°C to -30°C.

The condensing coil 55 condenses and collects water vapor generated within the vacuum chamber 51.

Although there is one cold trap 53 in the illustrated configuration example,
Two units may be provided and operated by switching alternately.

Further, in the illustrated configuration example, the cold trap 53 is the vacuum chamber 5.
Although the cold trap 53 is provided outside the vacuum chamber 51, the cold trap 53 can also be provided directly inside the vacuum chamber 51.

In the illustrated configuration example, a vacuum evacuation device 57 such as a vacuum pump or the like is connected to the cold trap 53 via a vacuum pipe 56.
are connected. The evacuation device 57 has the ability to maintain the degree of vacuum inside the vacuum chamber 51 at, for example, 2 to Q.1 Torr.

The vacuum freeze-drying apparatus 50 is equipped with a drying material supply means for supplying the frozen granular material to be dried B into the vacuum chamber 51 . In the illustrated configuration example, the drying material supplying means includes an intermittent supplying device 58 that supplies a predetermined amount of frozen granular dried material B into the vacuum chamber 51, and the intermittent feeding device 58 extends in the vertical direction. A piping 59 for supplying granular materials to be dried that opens at the upper part of the vacuum chamber 51; and a piping 59 for supplying granular materials to be dried.
A granular dried material storage chamber 60 provided in the middle of the
It consists of a pair of on-off valves 61 and 62 provided on the inlet side and the outlet side of the granular dried material storage chamber 6o,
In the illustrated configuration example, the ice maker 40 is connected to a granular dried material storage chamber 60 via an on-off valve 61 on the inlet side.

In this configuration example, by opening the artificial side on-off valve 61 with the outlet side on-off valve 62 closed, the granular dried material B frozen and made in the ice maker 40 is stored at one end in the chamber 60, Thereafter, the on-off valve 61 on the population side is closed and the on-off valve 62 on the outlet side is opened, so that the frozen granular dried material B in the chamber 60 is transferred to the vacuum chamber without significantly reducing the degree of vacuum in the vacuum chamber 51. 51.

The vacuum chamber 51 is provided with a conveyor 63 for continuously or intermittently conveying the frozen granular dried 'liB supplied into the vacuum chamber 51.

In the illustrated configuration example, three conveyors 63 are arranged in three stages in the vertical direction, and the conveyor directions of the conveyors 63 are alternately reversed, so that the granular dried material B discharged from the upper conveyor 63 is sequentially It is supplied onto a lower conveyor 63.

As the conveyor 63, a belt conveyor, a vibration conveyor, an apron conveyor, a net conveyor, a steel belt conveyor, etc. can be used, and they can be used in an appropriate combination. In addition, conveyor 6
The number of stages of 3 can be appropriately selected depending on the processing amount, moisture content, etc. of the granular material to be dried B.

Inside the vacuum chamber 51, a plurality of far-infrared ray irradiation means are provided for irradiating far-infrared rays onto the frozen granular material to be dried B supplied into the vacuum chamber 51. The far-infrared irradiation means includes a far-infrared ray radiator 64 and a far-infrared reflector 65 for reflecting a part of the far-infrared rays emitted from the far-infrared ray radiator 64 toward the granular materials B on the conveyor 63. In the illustrated configuration example, a plurality of rod-shaped far-infrared radiators 64 and reflectors 65 are arranged above the conveyor 63 at each stage. The shape of the far-infrared radiator 64 is as follows:
In addition to the rod shape, the shape may be a plate shape, a lamp shape, or a combination thereof.

Although detailed illustration is omitted, the far-infrared radiator 64 has a ceramic outer shell that houses a heating source inside, or a metal outer shell that houses a heating source inside. It is desirable to have a body and a ceramic spray coating on its outer surface. The ceramic shall be an oxide of one or more of the following: aluminum, magnesium, chromium, silicon, zirconium, beryllium, lithium, titanium, vanadium, iron, cobalt, nickel, antimony, and tin. is desirable. Further, as a heating source for the far-infrared radiator 64, that is, a primary heating element, hot water, heated oil, heated steam,
Although combustion gas or the like may be used, it is best to use an electric heater.

The vacuum chamber 51 further includes a crusher 66 for finely pulverizing the granular dry matter C discharged from the conveyor 63 at the lowest stage, and a crusher 66 for intermittently discharging the pulverized granular dry matter C to the outside of the vacuum chamber 51. The intermittent discharge device 67 includes a granular dry matter discharge pipe 69 extending downward from the crusher 66 and connected to the product storage tank 68, and a granular dry matter discharge pipe 69. It consists of a granular dry material storage chamber 70 provided in the middle of the granular dry material storage chamber 70, and a pair of on-off valves 71 and 72 provided at the inlet and outlet sides of the granular dry material storage chamber 70.

The on-off valves 71 and 72 open and close alternately, and the on-off valve 7 on the outlet side
2 is closed, the on-off valve 71 on the inlet side is opened, and the granular dry material C finely crushed by the crusher 66 is
It is supplied into the chamber 70 without greatly reducing the degree of vacuum in the vacuum chamber 51, and then the on-off valve 71 on the inlet side
is closed and the opening/closing valve 72 on the outlet side is opened, so that the granular or powdery dry matter C in the chamber 70 is transferred to the product storage tank 6.
It is discharged within 8 days.

In the illustrated configuration example, the vacuum freeze-drying apparatus 50 includes a temperature sensor 73 that detects the surface temperature of the far-infrared radiator 64;
A temperature control device 74 that controls the heat load on the far-infrared radiator 64 according to the output of the temperature sensor 73 is provided. When the heating source of the far-infrared radiator 64 is an electric heater, the controller 74 is configured to control the current supplied to the electric heater. The operating temperature range of the far-infrared radiator 64 is normally 20 to 600°C, but depending on the physical properties, shape, etc. of the material to be dried It is desirable to divide the far-infrared radiator 64 into several sections and control each section to an appropriate temperature in accordance with the changes in the lapse rate drying M). here,
The far-infrared radiator 64 is divided into three sections according to the number of stages of the conveyor 63, and a temperature sensor 73 is disposed near the far-infrared radiator 64 in each section. Based on this, the temperature control device 74 is configured to control the heat load of the far-infrared radiator 64 in each section. For example, the temperature of the far-infrared radiator 64 in the three sections is 3.
The temperature is controlled at 00°C, 200°C in the second stage, and 100°C in the third stage. When controlling the heat load on the far-infrared radiator 64 for each section, control becomes easier if the primary heating element of the far-infrared ray radiator 64 is an electric heater.

In the configuration example of the vacuum freeze-drying apparatus 50 shown in FIG.
When performing vacuum freeze-drying of the frozen granular material to be dried B, first, the condensation coil 55 of the cold trap 53 is maintained at a low temperature of, for example, -40° C. by operating the refrigerator 54, and then the vacuum evacuation device 57 is operated. For example, the vacuum chamber 51 is maintained at a vacuum level of 0.77 Torr. Next, the conveyor 63 is operated, and the frozen granular material to be dried B is supplied from inside the chamber 0 onto the conveyor 63 at the top stage.

In this case, it is preferable to adjust the deposition thickness of the granular dried material B on the conveyor 63 to an optimum value.

Frozen granular dried material B produced by the ice maker 40
The particle size is usually 0.5 mm or more, but if the particle size is 20 mm
m or more, it becomes difficult for far infrared rays to penetrate into the interior of the material to be dried B, and the moisture inside becomes difficult to sublimate. Therefore, uneven drying is likely to occur.

Further, the ratio of the surface area (sublimation area) to the accumulation of the material to be dried B is also limited, and drying takes time. Therefore, the particle size of the granular material to be dried B is preferably within the range of 0.5 to 20 maI.

On the other hand, the granular dried material B having a particle size within the above range was
Since there is a limit to the ability to transmit far infrared rays when depositing on 3, experiments have shown that when the deposition thickness exceeds 40111111, the temperature gradient between the surface and the deep part of the deposited layer becomes large. Therefore, if the temperature of the far-infrared radiator 64 is increased in order to accelerate the sublimation of moisture in the granular dried material B in the deep part, excessive heat will be applied to the dried part of the surface layer, causing deterioration of the components. . Moreover, the ice partially melts due to the temperature gradient, causing melting of the components. As described above, when the deposition thickness exceeds 40 mm, the quality of the product deteriorates and non-uniformity occurs. On the other hand, if the thickness of the granular dried material B deposited on the conveyor 63 is less than 2 mm, it will be difficult to adjust the thickness due to the relationship with the particle size of the dried material B, and the deposited thickness will become uneven. There is a risk.

From the above, it is desirable to adjust the thickness of the granular dried material B deposited on the conveyor 63 within the range of 2 to 40 mm.

Frozen granular dried material B deposited on the conveyor 63
The far infrared radiator 6 is transported by the conveyor 63.
It is irradiated with far infrared rays emitted from 4. The far-infrared radiator 64 may sequentially generate heat in accordance with the moving speed of the granular material to be dried B on the conveyor 63. Since the far infrared rays emitted from the far infrared radiator 64 match well with the infrared absorption characteristics of moisture, the irradiation of far infrared rays efficiently supplies energy to the granular material to be dried B, thereby drying the granular material B in a frozen state. The moisture in the dried material B is efficiently sublimated.

The moisture removed from the granular material to be dried B is condensed and collected by the condensation coil 55. Due to sublimation of moisture, the granular dried material B becomes granular dried material C on the conveyor 63, falls from the lowest stage conveyor 63 into the crusher 66, is crushed, and is passed through the on-off valve 71. 72 causes the product to pass through the chamber 70 and be stored in the product storage tank 68 one after another.

Concentration device 10 exemplified above. According to the working conditions of the ice maker 40 and the vacuum freeze-drying device 50, for example, a dilute aqueous solution containing various amino acids (amino acid concentration 3 wt%) is processed by the concentrator 10 into lQ vo 1% (amino acid concentration 30-t
%), and this concentrated solution was frozen into granular ice using an ice maker 40, and this was used as the material to be dried B.
When far-infrared rays were irradiated using the far-infrared radiator 64, which was entirely rod-shaped, the heat-receiving area was 9.7 m and the amount of heat was approximately 10 kg10.
It was possible to process approximately r. At this time, the temperature of the material to be dried B is about -20°C during constant rate drying, and 20 to 40°C when taken out.
℃, and a powdery dry product (amino acid powder) of good quality was obtained. It was confirmed that the obtained powder product, ie, amino acid powder, is stable and can be stored for a long time, and moreover, when redissolved in water, the original physical properties are restored.

In the configuration example shown in FIG. 1, the concentration step, freezing ice-making step, and vacuum freeze-drying step can be performed continuously, but each step can also be separated and processed individually. For example, if the concentrated raw material is frozen and made into granular dried material using a separate ice maker, the ice maker 40 shown in FIG. 1 is separated from the concentration tank 24 and used as a freezing tank for the granular dried material B. be able to.

FIG. 5 shows another configuration example of the vacuum freeze-drying apparatus 50. In the figures, the same reference numerals are given to the same components as in the above configuration example. In this configuration example,
The vacuum tank 51 includes a tank main body 51a having an opening at one end, and a JR 51b for opening and closing the opening of the tank main body 51a. A refrigerating fan 75 and a condensing coil/refrigerating coil 76 are disposed at the rear of the tank body 51a. Refrigerator 54, exhaust valve 52, vacuum piping 56, and vacuum exhaust device 5
7 etc. perform the same action as the configuration example shown in FIG.

Inside the tank body 51a of the vacuum tank 51, a carry-in jig 77 is provided as a drying material supply means. Carrying jig 7
7 can be carried into the tank main body 51a through the opening of the tank main body 51a, and can also be carried out. In order to facilitate the loading and unloading of the loading jig 77, wheels 78 are provided at the bottom of the loading jig 77.

The carry-in jig 77 is provided with a plurality of dish-shaped trays 79 that carry frozen granular materials B to be dried. A plate-shaped far-infrared radiator 64 is arranged above each tray 79 and fixed to a loading jig 77 . The shape, material, number, operating temperature range, etc. of the far-infrared radiator 64 can be the same as the configuration example shown in FIG. In the configuration example shown in FIG. 5, the trays are arranged in two stages, one above the other, but the number of stages is not limited to this.

The vacuum freeze-drying apparatus 50 shown in FIG. A temperature sensor 73 that detects the temperature, and a temperature control device 81 that controls the thermal load of the far-infrared irradiator 64 to an optimum value in accordance with the output signals of the weighing device 80 and the temperature sensor 73.

In the vacuum freeze-drying apparatus 50 shown in FIG. 5, the material to be dried B may be supplied into the vacuum chamber 51 by pre-frozen in granular form externally and filled onto a tray 79. After the unfrozen granular dried material B is filled onto the tray 79 and supplied into the vacuum chamber 51, it may be pre-frozen or self-frozen within the vacuum chamber 51. The condensing coil/refrigeration coil 76 is used as a condensing coil during self-freezing and vacuum freeze-drying, and is used as a freezing coil during pre-freezing.

When performing vacuum freeze-drying of the granular material to be dried B that has been previously frozen externally using the vacuum freeze-drying apparatus 50 shown in FIG.
9 to a thickness preferably within the range of 2 to 40 mm, the general jig 77 is loaded into the tank body 51a of the vacuum chamber 51, the door 51b is closed, and the condensing coil/refrigeration coil 76 is frozen. The vacuum chamber 51 is maintained at a low temperature of, for example, -40° C. by operating the vacuum pump 54, and the vacuum chamber 51 is maintained at a vacuum level of, for example, 0.77 Torr by operating the evacuation device 57.

Next, the far-infrared radiator 64 is made to generate heat, and the far-infrared rays are irradiated from the far-infrared radiator 64 to the granular dried material B on the tray 79. The temperature of the far infrared radiator 64 is measured by a measuring device 80.
Based on the output signal of the temperature sensor 73, the temperature is sequentially controlled to 150° C., 100° C., etc., depending on the drying state of the object B to be dried. The material to be dried B is irradiated with far-infrared rays suitable for sublimating moisture from the far-infrared radiator 64 and is dried.

The moisture removed from the material to be dried B is condensed and collected by the coil 76.

It was confirmed that under the working conditions exemplified above, a dried product substantially similar to that of the vacuum freeze-drying apparatus shown in FIG. 1 could be obtained.

〔Effect of the invention〕

As is clear from the above description, according to the present invention, an aqueous solution raw material is concentrated by far infrared heating under reduced pressure, frozen into ice cubes, and then freeze-dried by far infrared heating under vacuum, which requires less energy. It becomes possible to efficiently obtain dry products. Moreover, since the frozen material to be dried is granular, uneven drying is less likely to occur, making it possible to obtain a high-quality dried product.

[Brief explanation of the drawing]

FIG. 1 is an overall schematic configuration diagram showing an example of the configuration of a QQ compressor, an ice maker, and a vacuum freeze-drying device for carrying out the method of the present invention, and FIG. 2 is a schematic diagram of main parts showing another example of the configuration of the concentrator. 3 is an enlarged sectional view of the tray in the 4-condensation device shown in FIG. 2, 4 is a schematic diagram of the main parts showing another example of the configuration of the concentrator, and 5 is vacuum freeze-drying. It is a schematic block diagram which shows another structural example of an apparatus. In the figure, 10 is a concentration device, 11 is a concentration tank, 30 is a far-infrared radiator, 40 is an ice maker, 50 is a vacuum freeze-drying device, 51 is a vacuum tank, 51a is a tank body, 5'lb is a door, 53
57 is a cold trap, 57 is a vacuum exhaust device, 58 is an intermittent supply device, 63 is a conveyor, 64 is a far-infrared radiator, 6
5 is a reflector, 66 is a crusher, 67 is an intermittent discharge device, 73
is a temperature sensor, 74.81 is a temperature control device, 76 is a condensing coil/refrigeration coil, 77 is a loading jig, 79 is a tray,
80 is a weighing machine, A is a stock solution, B is a granular dried product, and C is a granular dried product. Figure 2 Figure 3

Claims (1)

[Claims] 1. A step of concentrating the aqueous solution raw material by irradiating the aqueous solution raw material with far infrared rays in a depressurized concentration tank, and forming and freezing the concentrated raw material to produce a frozen granular dried material. A method for producing a granular dried product, comprising: a step of irradiating the granular dried material in a frozen state with far infrared rays in a vacuum chamber to sublimate moisture in the granular dried material and dry it. 2. The method for producing dried granular material according to claim 1, characterized in that far infrared rays are irradiated while the aqueous solution raw material is made to flow down along multi-stage trays in the concentration tank. 3. A vacuum freeze-drying apparatus for use in carrying out the method for producing dried granular material according to claim 1, comprising a vacuum chamber and a device connected to the vacuum chamber to evacuate the inside of the vacuum chamber. a cold trap device for condensing and collecting moisture in the exhaust gas; a drying material supply means for supplying frozen granular materials to be dried into the vacuum chamber; A vacuum freeze-drying apparatus comprising far-infrared irradiation means for irradiating far-infrared rays to a granular material to be dried. 4. The far-infrared irradiation means is equipped with a far-infrared radiator,
4. The vacuum freeze-drying apparatus according to claim 3, wherein the far-infrared radiator has a shape of a rod, a plate, a lamp, or a combination thereof. 5. The vacuum according to claim 4, wherein the far-infrared radiator has an outer shell housing a heating source therein, and the outer shell is made of ceramic. Freeze drying equipment. 6. Claim 4, characterized in that the far-infrared radiator has a metal shell housing a heating source therein, and a ceramic spray coating film provided on its outer surface. The vacuum freeze-drying device described in . 7. The ceramic is made of one or more oxides of aluminum, magnesium, chromium, silicon, zirconium, beryllium, lithium, titanium, vanadium, iron, cobalt, nickel, antimony, and tin. A vacuum freeze-drying apparatus according to claim 5 or 6, characterized in that: 8. The vacuum freeze-drying apparatus according to claim 5 or 6, wherein the heating source of the far-infrared radiator is an electric heater. 9. Claim 4, characterized in that the far-infrared ray irradiation means includes a far-infrared reflector that reflects a part of the far-infrared rays emitted from the far-infrared radiator toward the granular material to be dried. Vacuum freeze-drying equipment as described in section. 10. The dried material supplying means is equipped with an intermittent supply device that supplies a predetermined amount of frozen granular dried material into the vacuum chamber, and the granular dried material supplied into the vacuum chamber is contained in the vacuum chamber. 4. The vacuum freeze-drying apparatus according to claim 3, further comprising a conveyor for continuously or intermittently transporting the liquid, and a far-infrared irradiation means disposed above the conveyor. 11. The vacuum freeze-drying apparatus according to claim 10, wherein the conveyor is a belt conveyor, a vibratory conveyor, an apron conveyor, a net conveyor, a steel belt conveyor, or a combination thereof. 12. A plurality of conveyors are arranged in multiple stages in the vertical direction, and the transport directions of the conveyors are alternately reversed, and the granular material to be dried discharged from the upper conveyor is sequentially supplied onto the lower conveyor. 12. The vacuum freeze-drying apparatus according to claim 10 or 11, wherein the far-infrared irradiation means is arranged above the conveyor of each stage. 13. The intermittent supply device includes a pipe for supplying granular materials to be dried that extends in the vertical direction and opens at the upper part of the vacuum chamber, and a storage chamber for storing granular materials provided in the middle of the piping for supplying granular materials to be dried. 11. The vacuum freeze-drying apparatus according to claim 10, comprising: a pair of on-off valves provided on the inlet side and the outlet side of the granular material to be dried storage chamber. 14. The vacuum chamber is equipped with a crusher for crushing the granular dry matter and an intermittent discharge device for intermittently discharging the granular dry matter crushed by the crusher to the outside of the vacuum chamber. 11. The vacuum freeze-drying apparatus according to claim 10. 15. The intermittent discharge device includes a granular dry material discharge pipe extending downward from the crusher, a granular dry material storage chamber provided in the middle of the granular dry material discharge pipe, and an inlet side of the granular dry material storage chamber. 15. The vacuum freeze-drying apparatus according to claim 14, comprising a pair of on-off valves provided on the outlet side. 16. Claims 3, 10, or 12, comprising a temperature control device that detects the surface temperature of the far-infrared irradiation means and controls the heat load of the far-infrared irradiation means. The vacuum freeze-drying device described in . 17. The vacuum chamber is equipped with a tank main body having an opening at one end and a door for opening and closing the opening of the tank main body, and the drying material supply means passes through the opening of the tank main body to the tank main body. The device is equipped with a carrying jig that can be carried into the interior, and the carrying jig is equipped with a tray that supports frozen granular materials to be dried.Far-infrared irradiation means is placed above the tray to control the carrying-in process. The vacuum freeze-drying device according to claim 3, wherein the vacuum freeze-drying device is attached to a tool. 18. A measuring means for measuring the weight change due to drying of the granular dried material on the tray and converting it into an output signal, a temperature sensor for detecting the surface temperature of the far-infrared irradiation means, and the output of the measuring means and the temperature sensor. 18. The vacuum freeze-drying apparatus according to claim 17, further comprising a temperature control device that controls the heat load of the far-infrared irradiation means in accordance with a signal.