JP3985241B2 - Freeze vacuum dryer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a freeze vacuum drying apparatus that freezes an object to be dried containing moisture such as foods and pharmaceuticals and evaporates and dries the moisture and solvent in a frozen state under vacuum.
[0002]
[Prior art]
Conventionally, as shown in FIG. 4, a freeze vacuum drying apparatus has a configuration in which a vacuum evacuation apparatus e having a cold trap c and a vacuum pump d is connected to a vacuum drying chamber b in which an object to be dried a is accommodated. In general, the inside of the drying chamber b is depressurized by the vacuum exhaust device e to freeze the material to be dried a, and then the drying chamber b is further evacuated by the vacuum exhaust device e. As a result, the frozen water is sublimated and dried. A shelf f that can be moved up and down and heated and cooled is provided in the vacuum drying chamber b, and the object to be dried a placed on the shelf f is heated during drying to promote sublimation. Has been done. When the material to be dried a is a medicine, the vial bottles filled with the chemical solution are arranged on the shelf f in the vacuum drying chamber b in a half-plugged state, and when the drying is finished, the vertical interval of the shelf f is set. After being moved so as to narrow, the bottle is stoppered, and then the door g is opened and taken out to the outside.
[0003]
Moreover, when an anatase-type crystal titanium oxide film is irradiated with ultraviolet light, the phenomenon (photocatalytic function) that decomposes the water adhering to the film and the active oxygen generated at that time decomposes the filth adhering to the film (photocatalytic function). And was found to have a function of killing bacteria.
[0004]
[Problems to be solved by the invention]
When the material to be dried a is a food or a medicine, in order to prevent the inside of the vacuum drying chamber b from being contaminated with bacteria, ethylene oxide gas (EOG) is allowed to flow into the drying chamber b, or Sterilization and sterilization are performed by flowing high-temperature steam and aseptic washing water. However, there is a safety concern regarding the EOG remaining in the drying chamber b, and in order to enable high temperature steam cleaning, it is necessary to provide the drying chamber b with pressure resistance, which makes the apparatus expensive. There is. In addition, these sterilization methods including washing with aseptic washing water are not preferable because the operation of the freeze-drying apparatus needs to be stopped and performed periodically, which reduces the operation efficiency of the apparatus.
[0005]
An object of the present invention is to provide a freeze vacuum drying apparatus that can maintain a vacuum drying chamber in a sterilized state for a long period of time, has high operating efficiency, and can be manufactured at low cost.
[0006]
[Means for Solving the Problems]
In the present invention, a vacuum drying chamber containing a material to be dried is evacuated by a vacuum evacuation device connected thereto, and the material to be dried is freeze-vacuum dried, the surface exposed to the chamber of the vacuum drying chamber The above-mentioned object is achieved by having a light source that covers a thin film of titanium oxide, irradiates the thin film and sterilizes it by photolysis , and a reflecting mirror whose surface is covered with a thin film of titanium oxide. I did it. Furthermore, it is preferable to have a shelf plate which is processed into a reflecting mirror surface and whose surface is covered with a thin film of titanium oxide. It is effective to use a light source that emits ultraviolet light having a wavelength of 400 nm or less as the ultraviolet light source.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
The embodiment of the present invention will be described with reference to the drawings. In FIGS. 1 and 2, reference numeral 1 denotes a vacuum drying chamber provided with a plurality of shelves 2, and reference numeral 3 is connected to the vacuum drying chamber 1. An evacuation apparatus provided with a cold trap 4 and a vacuum pump 5 is shown. A refrigerant is circulated from the refrigerator 6 to the cold trap 4 so that mainly moisture in the drying chamber 1 is condensed and collected. On each shelf plate 2, an object to be dried 8 such as a chemical solution or food stored in a tray or a vial bottle 7 is placed. The object to be dried 8 is opened and removed by opening the door 1 a of the drying chamber 1. When the object to be dried 8 is stored in the vial 7, a sealing cylinder 9 provided above the drying chamber 1 is used. After the vial bottle 8 is capped in the drying chamber 1, it is taken out. 10 is an air compressor for operating the sealing cylinder 9, 11 is a melted water introduction pipe for melting ice condensed in the cold trap 4, 12 is a drain pipe for melted water, and 13 is connected to the sterile room through a sterile filter. This is an atmospheric introduction pipe.
[0008]
Such a configuration is not particularly different from the conventional freeze vacuum drying apparatus, and the inside of the drying chamber 1 containing the material to be dried 8 is decompressed by the vacuum pump 5 while operating the cold trap 4 at about −45 ° C. The dried product 8 is frozen, and the interior of the drying chamber 1 is further evacuated to a vacuum of about 6.7 Pa to sublimate the moisture in the frozen product to be dried 8 so that the drying is performed in the same manner as the conventional one. However, in the present invention, the surface exposed to the interior of the drying chamber 1 such as the inner wall and the shelf 2 is contaminated with bacteria, or the surface is covered with a titanium oxide thin film 14 in order to prevent dirt from remaining. The ultraviolet light source 15 was provided in the drying chamber 1.
[0009]
This will be further explained. A thin film 14 is formed by sintering titanium oxide on the inner surface of the drying chamber 1 and the surface of the shelf plate 2 made of stainless steel or mild steel. Four ultraviolet light sources 15 were provided so as not to cause dark portions. The thin film 14 had a thickness of about 1 to 3 microns, and the ultraviolet light source 15 used was irradiated with ultraviolet light having a wavelength of 400 nm or less. In the drying chamber 1, the operating portion of the sealing cylinder 9 and the like are present as internal components, and it is preferable to coat these with titanium oxide as much as possible. Further, instead of adding the light source 14, as shown in FIG. 3, a reflecting device in which the reflecting mirror 16 and the shelf board 2 are processed into a reflecting mirror surface may be provided to reduce the portion that tends to be a dark part. A thin film 14 is also formed on 16 and the reflecting mirror surface.
[0010]
A test piece with a titanium oxide thin film having the same thickness as that of the drying room is placed in the drying chamber 1, and live bacteria (MRSA, E. coli) are attached to the surface of the test piece so that the surface of the test piece becomes 1000 lux. When the ultraviolet light source 15 was irradiated for 1 hour, 99.9% of viable bacteria were sterilized. As for sterilization, water is decomposed on the surface of titanium oxide, and the action of active oxygen generated at that time is large, so that the drying chamber is opened to the atmosphere not only under vacuum but also when taking in and out dry matter. It was found that the sterilization effect was further increased by irradiating light intensively when the water content of the water was increased.
[0011]
【The invention's effect】
As described above, according to the present invention, the surface exposed in the vacuum drying chamber of the freeze vacuum drying apparatus is covered with a thin film of titanium oxide, and an ultraviolet light source for irradiating the thin film with ultraviolet rays is provided in the vacuum drying chamber. The number of bacteria in the vacuum drying chamber can be greatly reduced compared to the previous one, and it is highly clean and safe. Since the number of times can be reduced, the operation efficiency can be increased, the production cost can be reduced, and the production thereof is easy.Therefore, by providing a plurality of ultraviolet light sources or a reflection device in the drying chamber, The thin film formed by reducing the dark part in the drying chamber can be effectively operated for photocatalysis, and by providing a reflection device, the structure is simplified and can be manufactured at low cost. Drying chamber can be improved further sterilization effect when irradiated with light intensive when that is open to the atmosphere.
[Brief description of the drawings]
FIG. 1 is a cut-away side view showing an embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a cut-away side view showing another embodiment of the invention. 4] Cutaway side view of conventional example [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Vacuum drying chamber, 3 Vacuum exhaust apparatus, 8 To-be-dried object, 14 Thin film, 15 Ultraviolet light source, 16 Reflector,

Claims (4)

An apparatus for vacuum freeze drying該被dried product was evacuated by the vacuum evacuation device connected to a vacuum drying chamber containing the material to be dried thereto,
A light source for covering the surface exposed to the inside of the vacuum drying chamber with a thin film of titanium oxide, irradiating the thin film to effect sterilization by photolysis, a reflecting mirror having a surface covered with a thin film of titanium oxide; A freeze vacuum drying apparatus characterized by comprising: The freeze-drying apparatus according to claim 1, further comprising a shelf plate processed into a reflecting mirror surface and having a surface covered with a thin film of titanium oxide. The freeze-drying apparatus according to claim 1 or 2, wherein the light source is an ultraviolet light source, and a plurality of the light sources are provided. The light source vacuum freeze-drying apparatus according to claim 1, wherein the irradiation with ultraviolet light having a wavelength of not more than 400 nm.

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