JPS5822873A - Vacuum freezing drying method of liquid material and its device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention is characterized in that the source material (including paste-like and mud-like materials) is frozen and loaded into a tray, and the source material is pulverized into a fine powder after freezing, or the raw material is frozen into a fine powder. (including when loading materials into a tray), the tray is placed within the shelf spacing of a heating tank arranged in multiple stages in a drying chamber maintained in a vacuum,
This invention relates to a vacuum freeze-drying method for drying a source material by supplying heat of sublimation from a heating tank, and to improvements in the equipment used directly to carry out the method.

An object of the present invention is to significantly shorten drying time and reduce freeze-drying costs without complicating the handling of the source material to be dried and the trays in which it is frozen and loaded. There is a particular thing.

Next, the present invention will be sequentially explained with reference to the drawings while comparing with the conventional means.

FIG. 1 is a schematic illustration of a conventional method of freezing source material in a tray, placing the tray within the shelf spacing of a heating tank in a drying chamber, and drying by supplying sublimation heat from the heating tank. In the figure, A is a drying chamber, a is a heating tank installed in multiple stages in the drying chamber A, B is a tray arranged within the shelf spacing of the heating tank a, and (1) is a heating tank installed in multiple stages in the drying room A. #l+i An upper heating shelf located below the tray B arranged within the shelf interval in a..., (2) is an upper heating shelf located above the tray B, (11) is the bottom surface of tray B arranged within the shelf spacing of heating tank a, (a) is the free surface of source material 1!1 frozen in tray B, (mark is the sublimation surface of frozen liquid material M, (4υ is the heat flow supplied from the upper heating shelf (11) to the sublimation surface side, (42) is the heat flow supplied to the sublimation surface from the upper heating shelf (2), and (50) is the heat flow supplied from the sublimation surface (7). The generated water vapor flow, L indicates the liquid thickness of the frozen liquid material ~1, and L indicates the dry layer thickness of the frozen liquid material IVI.

Fig. 2 also shows a conventional method in which a solid material N such as meat is frozen, placed between the shelves of a heating tank a in a drying chamber A, and dried by supplying sublimation heat from the heating tank a. In the schematic illustration of the means, (21) is the lower free surface which is the lower surface side to the frozen material, (22) is the upper free surface of the frozen material N, (
31) is the lower sublimation surface, (321 is the upper sublimation surface, 6υ
is the water vapor flow from the lower sublimation surface (31), the water vapor flow from the upper sublimation surface (31), !, is the lower dry layer thickness, -e
2 indicates the thickness of the upper dry layer.

Further, FIG. 8 is a detailed explanatory diagram of the present invention, and C is a combination tray consisting of an upper tray (6 and a lower tray 6υ) arranged within the shelf interval of the heating tank a in the drying chamber A. ,0υ
is the bottom surface of the lower tray [F]υ, which is the bottom surface of the tray C, and (2I) is the frozen liquid material loaded in the lower tray 6D.
1 free surface, so is the free surface of the inclined part of the frozen liquid material loaded in the upper tray tfJ2i, c31) is the lower tray 1)
The sublimation surface of the frozen liquid material M loaded in the layer tray 0
(41) is the heat flow from the upper heating shelf (]) toward the sublimation surface 1), (42)
1 indicates a heat flow from the second heating shelf (2) toward the sublimation surface C32)K, 6υ indicates a water vapor flow generated from the sublimation surface (31), and 62 indicates a water vapor flow generated from the sublimation surface (32). .

To date, the most widely used method for vacuum-freeze-drying the source material is to dry the freeze-pulverized source material in tray B.
or freezing the source material in tray B;
As shown in FIG. 1, the tray B is arranged between the multi-stage heating side a and the heating side a in the drying chamber A, and is left standing or moved horizontally between the shelves and vibrated. This is a method of drying by supplying sublimation heat from the heating side. With this method, only tray B comes into contact with the material to be dried;
Since there is no scattering of fine powder caused by agitation friction of the packed material bed, even when dry items are changed frequently, there is no fear of foreign matter contamination by just cleaning the tray, hygiene is easy to maintain, and the process is extremely simple. It is.

However, the above-mentioned method has a significant drawback in that the drying time is extremely long. If liquid (including paste/sludge) is injected (extended) into tray B and then freezes, the liquid should be placed in tray B.
It freezes in close contact with the inner surface, and the sublimation surface (g) and the escape surface for the sublimation vapor are only on the free surface (20) side of the frozen liquid material M.

In addition, when the frozen powder that has been freeze-pulverized is filled in tray B (the properties are almost the same as when the source material is frozen in tray B), the particle size becomes fine (a fraction of the diameter). When the powder packed bed is too dense (see below), the water vapor can only escape from the free surface (flood), and no sublimation surface is formed on the same side of the bottom of the tray.Therefore, these methods are similar to the schematic diagram in Figure 1. As shown in the diagram, the upper heating shelf (IJ) and the bottom of the tray (
The heat flow (4Il) that advances to the sublimation surface (30) via (11) is (
L-4) (L: total thickness, p: dry layer thickness, swamps range from 0 to L)
The heat flow (42) passes through the frozen layer (average thickness during the sublimation process '/ ) of the sublimation layer (increases to ! ) and proceeds from the upper heating shelf (2) to the free surface (2 layer (flow (41)
・(42) The water vapor flow side generated from the sublimation surface (to) K is the thickness! It passes through the dry layer (average /2) and escapes into the free space of the drying room. If the area of tray B is Δ, the area of the water vapor escape channel is also A.

This is shown in Figure 2 for the freeze-drying of the flat solid material N. From the lower and upper heating shelves (1)-(2),
Heat flow (41) proceeding to the lower and upper free surfaces (20.4)
・(42) is a sublimation surface (31) that passes through dry layer stone... e2 because water vapor can escape from the front and back sides of material N.
・(It does not reach 321, but since it becomes vertically symmetrical, considering the thickness of the dry layer passing through, ・!2 increases from 0 to 1/2, and the average thickness during the sublimation process is L/4, respectively. be.

Similarly, the average dry layer thickness through which the water vapor flow escaping from both sublimation surfaces (31) and (3) is L/, and the water vapor escape channel area is 2A.

It is known that the pressure difference △P caused by the flow of water vapor passing through a dry layer (porous body) is proportional to the flow rate and layer thickness, and inversely proportional to the layer area.
Since the pressure Ps is below the equilibrium vapor pressure Pf of the limit temperature Tl at which the assimilation of the frozen body is relaxed, the permissible sublimation rate (
The steam flow rate) is the pressure difference ΔP≦(P*1−Po).

Therefore, in the case of frozen material in a tray (FIG. 1), the sublimation rate is 4/4 compared to the case of flat solid material (FIG. 2).

Furthermore, since the same relationship holds true for the heat flow passing through the dried layer, the tray for the heat source in the dried layer, which can function at 1-1 f, as long as the temperature td of the dried surface does not exceed the allowable temperature during freeze-drying, is In the case of internally frozen materials, in the case of flat solid materials (Figure 2) -
Compared to , it is '/4. In the case of Figure 1, the heat flow in the dry layer can be supplemented by the heat flow f41)K flowing in the frozen layer, but the heat flow in the frozen layer is limited by the temperature difference between the heat flow and the thickness of the frozen layer at the bottom of the tray. Raise the temperature above the sublimation surface temperature. Therefore, if the drying rate constraint is overheating of the dry surface, the sublimation rate of the frozen liquid material in the tray will be reduced to 4 compared to the flat plate solid material, but if the drying rate constraint is If the temperature is relaxed, the heat flow within the frozen layer will actually reduce the sublimation rate below that of the flat solid material layer.

As outlined above, the main reason why freeze-drying of liquid material frozen in a tray takes a long time is that the escape surface for sublimated water vapor is limited to one side (free surface), and the passage thickness of heat flow and water vapor flow is doubled. This is because the sublimation area is reduced by half, and the same is true when the frozen particles that have been freeze-pulverized are filled into a tray and the particle size is small.

In addition to drying after freezing in a tray, the freeze-drying method for liquid materials includes freezing the liquid material outside the drying tray and then pulverizing it into granules ranging from one crane to several dragons, or using low-temperature antifreeze. The temperature of the sphere is adjusted to the linear temperature of the sphere, which is then frozen into granular particles, which is then filled into a tray.The method of directly filling and drying on a vibrating heating plate is the most suitable for large quantities such as coffee. It is used for single-item equipment for items with In the case of a packed bed of granular frozen material, the voids between the granules serve as vapor escape routes and the sublimated surface becomes the grain surface and expands, so the drying delay due to the difficulty of a vapor film, which is a disadvantage of conventional freeze-drying after freezing in a tray, is eliminated. Can be removed.

However, in the case of a stationary packed bed, the supply of sublimation heat to the inside of the packed bed increases due to particle formation, and in the case of an agitated packed bed on a vibrating hot plate, the supply of sublimation heat to the inside of the packed bed increases due to the sliding and splitting of particles. This adds other disadvantages, such as the collapse and pulverization of parts, the adhesion of fine powder to hot surfaces, and the scattering of fine powder. In particular, the freezing of liquid materials and the subsequent filling into trays or heating surfaces is an operation in an environment of several tens of degrees below zero, and would be too complicated if not automated. It has economic rationality other than dedicated continuous operation. For this reason, it has not become widespread except for mass-produced products, such as coffee.

In an attempt to eliminate the shortcomings of conventional methods using a method other than frozen granulation, for example, after freezing in a freezing tray, the flat frozen body is peeled from the freezing tray and transferred to another perforated bottom tray. Although there is a method of sublimating from both the front and back sides, it cannot be put to practical use due to drawbacks such as the complexity of the peeling process and the spillage of dry products from the bottom of the porous surface. Another attempt was to circulate antifreeze liquid that can control humidity outside the multi-tube of a vertical cylinder with a built-in vertical multi-tube, first filling the multi-tube with liquid material, cooling the outside of the tube, and causing the liquid material to flow from the tube wall into a circular tube shape. Another method is to drain the unmixed liquid in the inner core of the multi-tube from the bottom when it is half-frozen, then create a vacuum inside the multi-tube, sublimate the antifreeze, dry the frozen material inside the multi-tube, and scrape it off. However, since a considerable portion of the prepared raw material liquid is always left behind for the next use, it is unsuitable for anything other than equipment dedicated to long-term continuous production, and this method has not been put to practical use either.

In addition, as an earlier invention by the inventor of the present invention, Kobayashi (Japanese Patent Publication No. 1143/1973), liquid material was frozen in two trays, the free surfaces of which were placed facing each other, and a heating shelf and a heating machine were assembled into an assembled tray. There is a way to put it in between. Compared to a single tray, the thickness is halved and the surface area is doubled. In addition, 1. The relationship between the upper heating shelf and the upper tray, and the relationship between the lower heating shelf and the lower tray are symmetrical to the center line of the lower shelf, which has the advantage of rational heating control. . However, the operation of inverting the upper layer tray after freezing is complicated, and this method is not suitable for materials in which the undried product may peel off from the upper layer tray.

Furthermore, in the method of peeling the frozen body from the tray, all of the heat flow passes through the dry layer, so the heat flow within the frozen layer does not raise the temperature of the frozen part above the sublimation surface, and the relaxation of the frozen solidification is reduced to sublimation. Although it is suitable for materials where speed is a constraint, it is unsuitable when overheating of a dry surface is a constraint. The method of supplying heat from the bottom side of the tray with the openings facing each other is suitable when overheating the dry surface is a constraint because the entire heat flow passes through the frozen layer, but the relaxation of freezing and solidification is a constraint. There are also limitations in that it is not suitable for certain materials, and there are also drawbacks to its versatility.

The present invention aims to eliminate the disadvantages and difficulties of the above-mentioned conventional means and to further enhance the effect. ) In the vacuum freeze-drying method, the material is filled and frozen in a tray and then dried by placing it between multi-stage heating shelves installed in a drying chamber, as shown in Figure 8.
The trays arranged within the shelf spacing are a combination tray C in which an upper tray bag and a lower tray (61) are stacked in two layers, and the liquid material M is distributed to the upper tray I2 and the lower tray υ of the combination tray C. The heat flow from the lower heating shelf (2) is divided into 4 parts and the upper tray (2) receives the heat flow from the free surface (2).
Frozen material in 6 units and heat flow from lower heating shelf (1) (4
The thickness of the frozen liquid material in the upper and lower trays 61) and (67J) is adjusted so that the frozen material 1 in the lower tray 6υ that receives 1) on the tray bottom surface 01) completes sublimation at almost the same time.
, or the thickness and concentration of the liquid materials filled in the upper and lower trays and the bag can be selected so that sublimation is completed at almost the same time, and drying is performed. It is something to do.

In this way, the method of the present invention is based on the inventor's own past inventions (
This is to eliminate the shortcomings of (Special Publication No. 42-1148 and Special Publication No. 45-9715) and further enhance their effects.
It greatly shortens the long drying time, which is a shortcoming of the normal single-tray freezing method, and eliminates the weaknesses, complicated processes, and restrictions on compatible products of various improved methods that have already been submitted, and makes it possible to change varieties. It has the advantage of being suitable for frequent multi-product processing, high hygiene standards, and sterile and dust-free processing.

FIG. 4 is an example of a combination tray of a vacuum freeze-drying apparatus used to carry out the method of the present invention.

In this example, the inner dimensions of the lower tray 6υ are rIJW.

・It is a rectangle with a depth D1 and a side edge height Hl, and the inner dimension of the upper tray (621 is width W2 (W2 is (W, -2
δ)], depth D2 [2d compared to D2 beam]
It is a rectangular shape with a side edge height H2 (H2 is about half of Hl), and a side edge of two opposing sides with a length D2 has a tsuba (1) with a horizontal number n or more. 7. When the upper tray is stacked on the lower tray, the tsuba (72) of the upper tray rests on two sides of the lower tray as shown in Fig. 4, and the side W1 of the upper tray and the side W2 of the upper tray are parallel to each other with a gap of about d, and the bottom surfaces of both trays are ()-1, -8
2) are parallel at what distance, and the space between the two bases is
Continuing to the free space in the drying chamber through the gap d between both side edges of the length, D2.

When the lower tray is approximately thick and filled with liquid, the source material is injected from the container at the same time on each side of the upper and lower layers after combining the upper and lower trays 6υ・f32 (combining them to form an integrated tray C). Even when injecting through the injection cock, the lower tray (6
After pouring into the upper tray (621), the upper tray (621) may be stacked and then poured into the upper tray (621).Although manually,
Although it uses an automatic conveyor system, it is easy to operate, and even after injection, it can be transported and handled with the same ease as a single tray.

Even if the trays are cooled to several tens of degrees below zero after being charged between the trays in the drying chamber, the trays are frozen in a freezer separate from the drying chamber. You can move it between shelves. In any case, it is extremely simple to handle compared to the conventional complicated process of transferring the peeled frozen bodies to another porous bottom tray after inverting the tray, or inverting the upper freezing tray and putting it back down.

Next, the effects of the present invention will be explained with reference to the schematic explanatory diagram of FIG. 3.

The heat flow (41) from the lower heating side (1) flows through the lower tray (
61), passes through the frozen layer (Lt-g+) (the dry layer thickness of the inner material increases from 0 to Ll) and reaches the sublimation surface 01n. The average thickness of the frozen layer is LL/
In the case of the single tray in Figure 1, the ratio is 4 (approximately half the thickness), so even if approximately twice as much heat flow is supplied, the temperature difference between the bottom of the tray (old) and the sublimation surface (c31) is This is equivalent to the case shown in FIG.

” - Heat flow from heating shelf (2) (4th is upper tray f6
2) The free surface of the inner frozen material passes through the dried layer p2 (from 0 to the upper tray (increases to the total thickness L2 of the inner material in 6'IJ) and reaches the sublimation surface (321). The dried layer thickness is the average Ly The temperature difference between the dried surface and the sublimated surface is the same as that of the conventional means shown in FIG. 1, even when compared with the single tray case of the conventional means shown in FIG.

It passes through the layer transfer and exits into the space between the upper and lower trays, passes through the gaps d on both sides of the tray, and escapes into the free space of the drying chamber. gap d
Lt, for example W1=0.7m @D, =05m
Even in the case of dimensions of 1a@ is sufficient and the resistance can be ignored compared to the resistance within the dry layer.

Pass through the inverted layer and escape to free space. 43 + zp
2'-, so even if four times as much water vapor flow passes through as compared to FIG. 1, the pressure on the sublimation surface and in the free space can be kept at the same level as 1.

How much time can be shortened by optimal program heating compared to the conventional method depends on the properties of the material (the thermal conductivity of the frozen layer and the transformed layer, the material conductivity of the transformed layer, the frozen assimilation limit temperature, and the frozen layer). The above overview shows that the required time can be reduced by 1/2 to 1/4, depending on the combination of allowable dry section temperature, total thickness, etc.

The second advantage of the present invention is that it is possible to control not only the shelf temperature program but also the distribution of the filling thickness and liquid thickness to the upper and lower trays according to the properties of the material (combination of the above-mentioned items). By selecting the solid content concentration of each material to an optimum value, there is flexibility to realize a shorter drying time for materials with various properties.

If the drying rate is restricted by the temperature rise limit of the dry surface, the conventional means shown in Figure 2, which involves peeling off the tray and making both surfaces dry, would require a heat input path that does not pass through the dry surface. The method of turning the free surfaces of the material frozen in the tray inward is disadvantageous when freeze-relaxation limits the drying rate.

In the present invention, if there is a limiting factor in the temperature rise of the dry surface, the liquid thickness L2 of the liquid material to be distributed and charged in the upper tray (62) is adjusted depending on the degree of the temperature increase, that is, the total liquid thickness (L1 + L2 ) is smaller than 1/2 (for example, 4), the average heat input can be increased to three times that of the conventional method shown in Figure 1, and the remaining 2/3 of the total heat input is used to raise the It can be supplied via a frozen layer that is not heated, and on the other hand, if freezing relaxation is a limiting factor, increasing the heat input from the top and distributing it to the upper tray 0 without making the frozen part humid above the sublimation surface temperature. The liquid thickness L2 of the liquid material in the upper layer tray (62) and the liquid thickness of the liquid material in the lower layer tray (61) should be largely distributed in proportion to the heat input that can be supplied. By allocating these, the sublimation will be completed at the same time, and the constraining factors can be relaxed.

Furthermore, in general, as the concentration of a liquid increases, the ventilation resistance of the dried layer and the thermal resistance of the frozen layer increase, but the thermal resistance of the frozen layer decreases. Therefore, if we compare the initial concentration of the upper tray, where the thermal resistance of the dried layer prevents drying, and the optimal initial concentration of the lower layer, where the thermal resistance of the frozen layer prevents drying, they are different values. The optimum concentration for this is rather high.

The third measure is to adjust the gap between the bottom of the lower tray and the lower heating shelf to keep the total heat input from the upper and lower heating shelves at a maximum during the sublimation process. In a normal multi-tiered heating shelf, for the tray placed between the bottom tier and the second tier from the bottom, the second tier from the bottom is the upper heating shelf, but the second and 8th tier are the upper heating shelves. For ToV, which was heated during K1ff, the second shelf from the bottom is the lower heating shelf. Therefore, the temperatures of the upper and lower heating shelves are equal. Therefore, in the case of a vertically asymmetrical heating method, the temperature of the heating shelf is generally determined depending on whether the dried surface temperature of the material in the upper tray reaches the allowable temperature or the tray bottom temperature of the material in the lower tray reaches the freeze retention limit. , regulated by either one. This regulating factor may shift from one side to the other during the sublimation process, but if the regulation for the lower tray bottom surface temperature to reach its limit during the process is longer, then the lower tray bottom surface and the lower heating shelf surface If the regulation for the dried surface of the material in the two-layer tray to reach the permissible limit is longer, narrow the gap between the bottom of the lower tray and the lower heating shelf surface. The total heat input from can be expanded.

The fourth measure is the Japanese Patent Publication No. 45-97 by the inventor of the present invention.
It is to use method No. 15 in combination.

In other words, the ordinary shelves that are isothermally controlled are used as lower heating plates for all trays, and are controlled by an optimal program based only on the allowable limit of the lower tray, and apart from this, the upper tray and the upper In this method, another heating plate is provided between the lower surface of the shelf and acts as an upper heating plate, and the temperature is controlled by another optimum program based only on the allowable limit of the upper tray.

As mentioned above, it is not necessarily advantageous to use all of the measures in combination, including from an economic standpoint, and it may be more advantageous to use some of them. However, in one conventional method using a single-layer tray, the heat input from the upper and lower heating plates eventually merges into a single sublimation surface, increasing the temperature of the sublimation surface and causing the risk of melting of the frozen part. , in the method of the present invention, all the heat flow from the upper heating plate is absorbed into the upper tray freezing section,
The heat flow from the lower heating plate is absorbed by the lower tray freezing part and does not reach the upper tray. Therefore, the disadvantages of the vertically asymmetrical heating format can be easily eliminated or alleviated by independently selecting factors such as the material thickness, concentration, external heat transfer coefficient, and heating temperature of the upper and lower layers.

The combination of double trays shown in Fig. 4 is an example, in which the side edges of both trays are made vertical instead of being supported by the side edges of the lower tray by the horizontal flanges attached to the side edges of the upper tray. First, the tray may be supported without a horizontal flange by forming an inclined surface, or the bottom surface of the two-layer tray may be supported by the side edge of the lower tray. What is required is that a path be maintained through which sublimated water vapor from the free surface of the source material in the lower tray can escape into the drying chamber free space without undue flow resistance.

Alternatively, instead of combining the upper and lower trays in advance, two levels of support stands or support rails are provided between the shelves of the heating plate in the drying chamber, and the upper and lower trays are loaded separately. It may also be used as a tray.

Next, an example of the effect of shortening drying time according to the present invention will be shown.

Concentrated tomato liquid (paste) with a solid content concentration of 20%, total thickness 25
fil was placed between parallel heating plates, and the combination of temperature conditions was as follows: (a) Temperature of frozen part - (material) ℃ or less, temperature of dry part +5
0 ”C or less (b) Freezing line temperature -16℃ or less, dry area temperature +30
T) Comparing the freeze-drying times in the following two cases, as shown in the table below, in the case of the normal method (freezing in a single tray),
Both methods require a long time, and in the case of other methods in which the sublimation area is doubled, the time is shortened. However, double-sided sublimation of a flat plate-shaped frozen body, which transmits heat through the dried part, is effective in maintaining the low temperature of the frozen part.

It is advantageous in case (a), which is strict and lenient on temperature rise in dry areas.
In the opposite case (b), the shortening effect is slight; on the other hand, in the case of a double tray (Japanese Patent Publication No. 42-1143) in which the free surface of the frozen material in the tray faces inward, the shortening effect is small because heat is transferred through the frozen part. , is advantageous in case (b), which is sensitive to temperature rise in the frozen part and difficult to maintain low temperature in the dried part, and has a large +-1j shortening effect; This is inferior to when drying a frozen body. On the other hand, in the case of method (a), which is strict in maintaining low humidity in the frozen area and weak in raising the temperature in the dry area, the method of the present invention is to increase the thickness of the liquid in the upper tray, which conducts heat from the dry area, to be slightly thicker. <(13+n) By adjusting the liquid thickness in the lower tray to 12-, it is similar to the case of double-sided sublimation of a flat plate-shaped frozen body, but the time can be shortened, and on the contrary, it is difficult to raise the temperature of the dry area). Reduce the thickness of the liquid in the upper tray (
10 to 11 ms) K, and the liquid thickness in the lower tray to (1
5 to 14 Setsuho), the
For No. 143, freezing in a normal single tray 65 hours
26hr double-sided sublimation of frozen plate 25hr'
22 hr 22 hr method 26 hr 13 hr or more are examples, and the quantitative degree of the time reduction effect varies depending not only on the characteristics of the material and allowable temperature conditions, but also on the performance level of the equipment used. However, the above trend remains unchanged. The above example is 0.15 at a sublimation rate of 1Ki/1d of shelf.
For example, if you use a device that can maintain a vacuum of 14 Torr (relatively low capacity) at the same sublimation rate, you will be able to maintain the same level of low temperature in the freezing zone. Even with severe conditions, the degree of disadvantage of heat transfer through a frozen section is relatively large compared to heat transfer through a dry section. By adjusting the thickness distribution to the lower tray, it can be adapted to various conditions.

In summary, the present invention is suitable for use in addition to mass production.
Compared to the currently used freeze-drying of materials frozen in a single tray, the drying time can be reduced by 17 to 1/2 without increasing equipment costs or complicating the handling of materials and trays. It has wide practicality compared to conventional methods of shortening, which are either impractical due to the complexity of materials and tray handling, or are only rarely implemented due to narrow suitability conditions.

[Brief explanation of the drawing]

Figure 1 is a schematic explanatory diagram of the conventional vacuum freeze-drying method in which liquid materials are frozen in trays and dried by being placed between the shelves of a heating tank in a drying chamber, and Figure 2 is a diagram of solid materials that are frozen and dried. A schematic explanatory diagram of a conventional vacuum freeze-drying method in which drying is performed by placing the trays between the shelves of an indoor heating tank, FIG. FIG. 5 is a longitudinal sectional side view of the tray, FIG. 6 is a longitudinal sectional front view of the same tray, and FIG. 7 is a partially cutaway front view of the vacuum freeze-drying apparatus used in carrying out the present invention. . Explanation of drawing symbols A... Drying room a... Heating tank B... Tray C... Combination tray ■... Lower heating shelf L... Thickness of liquid material in tray 11... Tray Bottom! ... Thickness of the dry layer of liquid material in the tray 2
... Upper heating shelf Ll ... Thickness of liquid material in lower tray ... Free surface 21 of frozen liquid material ... Upper free surface 22 of frozen solid material ...
Free surface L2 at the bottom of the frozen solid material...Thickness stone of the liquid material in the upper tray... Dry layer on the lower surface side, 82.
・Dried layer 30 on the upper surface side ・Sublimated surface 31 ・・
・Sublimation surface 32...Sublimation surface 41...Heat flow from the lower heating tank/I2...''Heat flow from the two-part heating shelf 50...Water vapor flow 51...Water vapor flow 52...
・Steam flow 6J・Lower tray 62・Single layer tray 72・Tsuba M・Freezing liquid material N・・
・Procedural amendment for flat solid materials (voluntary) Director General of the Japan Patent Office Shima 1) Haruki Tono1, Indication of the case Showa Frost Year Patent Application No. 1212722, Title of the invention Vacuum freeze-drying method and apparatus for liquid materials3
, Relationship with the case of the person making the amendment Applicant 5 Date of the amendment order 6 Number of inventions increased due to the amendment 7 Subject of the amendment ``Description'' 8, Contents of the amendment Amending the description in an attached document . (1) In the specification, on page 7, line 10, the phrase "by vibrating" should be deleted. (2) In the specification, page 13, line 7, "supply of sublimation heat" is corrected to "heat transfer resistance of sublimation heat."that's all

Claims (1)

[Claims] 1) The source material is frozen in a tray, and the tray is
In a vacuum freeze-drying method in which the drying chamber is placed between heating tanks installed in multiple stages in a drying chamber kept in vacuum, and the heating tank supplies sublimation heat for drying, the frozen liquid material is loaded inside. The trays are placed within the shelf spacing of the heating tank, with the bottom of the upper tray and the opening of the lower tray facing each other, and the internal spaces of the upper and lower trays are connected to the drying chamber through the openings on the top side. In a state where it communicates with the free space of
The source material arranged in two layers and loaded into the trays has a liquid thickness of the frozen liquid material in the upper tray which receives sublimation heat from the upper heating tank to the free freezing surface;
The liquid thickness of the frozen liquid material in the lower tray, which receives sublimation heat from the lower heating tank to the freezing bottom surface via the tray bottom surface, is distributed in such a proportion that the sublimation ends of the frozen liquid materials are approximately the same. A method for vacuum freeze-drying a source material, which is characterized by pouring it into a tray, freezing it, and then drying it. 2) A drying chamber in which the internal atmosphere is maintained at a normal degree of vacuum, a heating tank installed in multiple stages within the drying chamber, and a source material frozen inside and installed within the shelf spacing of the heating tank. (2) The bottom outer surface of the upper tray maintains a predetermined distance from the bottom surface of the inner cavity of the lower tray, and (2) the space between the bottom surface of the lower tray inner cavity and the outer bottom surface of the upper tray The space formed in the drying chamber is configured into a combination tray that fits in a stacked state above and below, satisfying the condition that the space formed in the drying chamber communicates with the free space of the drying chamber through an opening having a predetermined area. Vacuum freeze-drying equipment for source materials.