JPS6311680Y2 - - Google Patents

Description

[Detailed explanation of the idea]

The present invention relates to a dehydration device, and more particularly to a dehydration device for radioactively contaminated animals, such as animal waste contaminated with radioactive substances or animal carcasses suspected of being contaminated. Conventionally, hot air drying has been widely used to dry objects, and it is extremely advantageous compared to other methods such as infrared rays, especially when drying needs to be done at a relatively high speed. It is recognized that As is well known, in drying using hot air, etc., thermal energy is applied only to the surface of the object to be dried, that is, to be dehydrated, so the drying time depends on the surface area of the object. It takes a long time to dry. In addition, when increasing the thermal energy applied to the surface to shorten the time, a large amount of decomposed gas is generated from the surface of the object, especially for organic objects, which creates new odor problems and damages the object itself. more likely to be damaged. For example, currently a large number of experimental animals are used for various purposes, and animal waste after use is usually disposed of by incineration or burial underground. However, if this animal has been subjected to a radioisotope administration experiment, the above-mentioned normal treatment cannot be performed. As is well known, the difficulty in final disposal of radioactive animal waste is largely due to the method of waste storage. In other words, since animal waste is easily decomposed, measures must be taken to prevent radioactive waste from decomposing until it is handed over to a specific processing organization, and the usual way to do this is to preserve the waste using formalin or other preservatives. be. However, this method makes subsequent processing in a specific institution, such as incineration, extremely difficult. Therefore, for example, if animal waste could be stored in a form that is easily incinerated without using preservatives as in the past, the above problems would not occur.
One possible method for this purpose is the drying of animal waste, but as mentioned above, for example, hot air drying poses problems of time and decomposition gas, and it is extremely difficult to use this method. Also, when animal waste is dehydrated for drying, a strange odor is generated.
Furthermore, if this waste is contaminated with radioactive materials, there is a possibility that the water vapor and gas generated from the waste may contain these materials. The purpose of the present invention is to provide a dehydration device that dehydrates radioactively contaminated animals so that they can be preserved in a form that is easy to incinerate, and also prevents unpleasant odors and radioactive materials from dissipating outside the system. DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention applied to dehydration of animal waste contaminated with radioactive materials (hereinafter referred to as radioactive animal waste or animal waste) will be described below based on the drawings. In the drawing schematically showing the apparatus of the present invention in partial cross section, the apparatus is composed of a dehydration section A that can be divided by dotted lines and a safety section B when the object to be treated includes radioactive materials. The dehydration section A includes a microwave generator 20, a storage chamber or microwave irradiation chamber 30 that limits the microwave electromagnetic field generated by the microwave generator,
A flow rate adjustment device 14 for supplying air to the storage chamber 30, an exhaust port 18 for continuously taking out air from the storage chamber 30, a cooling device 22 for cooling the gas from the exhaust port 18, a cooling device 22 It consists of a collection container 24 for collecting liquid cooled and liquefied by the storage chamber 30, and a device 50 for detecting a so-called empty state after completion of dehydration in the storage chamber 30. This device 50 can also be used as a monitor of the dehydration process, as described below. Safety part B captures trace amounts of low-molecular radioactive gas that may be present in the collection container 24 and prevents it from escaping outside the system when the object to be dehydrated contains radioactive organic matter. A heating device 2, such as an electric furnace, for drawing out gas from the collection container 24 and oxidizing it.
6. An adsorption device 28 connected to this heating device 26 and filled with a moisture absorbent 29 such as soda lime or silica gel and an adsorbent 41 such as activated carbon, a cold trap 43 for collecting tritium water, and ¹⁴ CO ₂
It consists of a carbon dioxide absorption device 44 and a suction pump 45 for absorbing carbon dioxide. The cold trap 43 and carbon dioxide absorption device 44 may be optional, but for example, they are described in Japanese Patent Application Laid-open No. 119286/1986 (Japanese Patent Application No.
43623), the purpose can be achieved efficiently. To explain in detail the apparatus shown in the drawings for radioactive animal waste, first, the animal waste 40 is wrapped directly or in something 42 that does not impede the passage of water vapor, such as paper or cloth, and then it is placed in the container 30 or in a second container. As shown in the figure, the air supply port 16' is made of a material transparent or transparent to microwaves, such as plastic or heat-resistant glass.
and sealed in a microwave transmission container 30' equipped with an outlet 18', which is placed in the storage chamber 30.
Air is supplied to the storage chamber 30 or container 30'. Air is supplied or forced through the pipe 12 from a suitable air source, and its flow rate is regulated by a suitable flow regulating device 14 provided in the flow path. This adjustment is necessary in order to efficiently draw water removed from the animal waste in the holding chamber 30 or container 30' through the outlet 18. A microwave generator 20, for example a magnetron, is activated in these conditions to place the animal waste 40 within a microwave field. This selectively excites the water molecules in the animal waste 40 and generates water vapor. This water vapor is carried by the supplied air and is quickly transported to the cooling device 22.
The liquid is liquefied and accumulated in the collection device 24. It is necessary for effective dehydration to quickly extract the water vapor generated at this time out of the microwave system, and for this purpose it is necessary to perform the above-mentioned flow rate adjustment. Furthermore, low-molecular compounds contained within the animal's body, such as a portion of lipids, may flow into the cooling device 22 by steam distillation. These are also the collection devices 24
are collected at the same time. When animal waste is disposed of in this way, odor is often a problem, and if this waste contains radioactive materials, sufficient safety measures must be taken to prevent these materials from escaping outside the system. is necessary. Therefore, in the present invention, the gas is taken out from the collection device 24 through the pipe 25 and guided to the heating device 26 filled with an oxidation catalyst such as copper oxide, where a complete oxidation reaction is carried out. Water, carbon dioxide, and other gas obtained after oxidation are transferred to the adsorption device 2 described above.
It is adsorbed and removed by 8. By using the adsorption device 28, even if radioactive substances, especially ³ H and ¹⁴ C, are present, almost all of them remain in the system. To further increase safety, a cold trap 4 connected to the adsorption device 28 is provided.
A device for trapping and removing radioactive substances consisting of 3 and a carbon dioxide absorption device 44 is used to prevent tritium and carbon 14, which may exist in the form of water and carbon dioxide, from escaping out of the system. As mentioned above, in this invention, water is extracted as water vapor by selectively imparting energy to water molecules using microwaves, so the maximum temperature reached is around 100°C, and at such temperatures the decomposition of the surface of organic matter occurs. There is almost no decomposition gas generation. Furthermore, only the dehydration reaction proceeds extremely efficiently, and there is almost no change in the shape of the sample solid. Furthermore, as described above, relatively low-molecular organic substances may be collected in the collection device 24, and radioactive substances may also be included in these organic substances. In such cases, the solvent may be removed by extraction with ether, hexane, etc., and the organic matter may be isolated as an oil or solid, and this form may be used as waste. Alternatively, the aqueous solution may be adsorbed and removed by directly passing through the activated carbon layer, and the activated carbon may be treated as combustible waste. Also, the adsorption device 2
The adsorbent etc. in 8 can be treated as solid waste. Normally, in microwave heating, if there is no water in the sample to be processed or if the sample is completely dehydrated, the microwave energy will no longer be absorbed, and it may accumulate in the chamber and eventually cause a discharge phenomenon. There is a risk of damaging itself. For this purpose, the illustrated apparatus solves the above problem by using a pipe that is transparent to microwaves and allowing water to flow through it. In the illustrated device, this consists of a U-shaped pipe 50, to which the water supply is supplied to the cooling device 22.
This is done by directly sending the water used in When such a configuration is used, the temperature of the water flowing through the pipe 50 rises rapidly upon completion of dehydration. Therefore, the dehydration process can be monitored by detecting this temperature rise. Measuring and indicating the temperature of the water in pipe 50 is obvious to those skilled in the art and will not be described in detail. When this device is used to dehydrate radioactive animal waste, the prevention of radioactivity dissipation outside the system is almost complete. However, in the embodiment, the possibility of extra-system dissipation is completely eliminated by maintaining the device itself under a vacuum. That is, the apparatus is housed in a housing 10 that is completely sealed except for the air supply port 16, the discharge port 46, and the water supply and discharge system, and the housing is evacuated through the exhaust port 52 to maintain a reduced pressure state. Example 1 Animal tissue contaminated with ^14C -glucose (pork)
180 g was dehydrated using the apparatus shown in FIGS. 1 and 2 equipped with a microwave irradiation device with a frequency of 2500 MHz and an output of 450 W. 110 g of water was removed in 15 minutes, which was complete dehydration. The dehydrated tissue was placed in a plastic bag and stored for one month. It remained stable with no changes such as corruption. During dehydration, no strange odor was generated and no radioactive substances were observed to dissipate. Example 2 Using the same equipment and under the same conditions as Example 1, ^14C
- 150 g of fish contaminated with glucose was treated for 15 minutes, resulting in complete dehydration of 110 g. After the dehydrated fish was stored in a plastic bag for one month, there was no change such as rotting and the fish remained stable. No strange odor or radioactivity dissipation was observed.

[Table] Although the present invention has been explained using radioactive animal waste as an example, it is not limited to this, but the present invention is not limited to this. It can also be used, for example, to dehydrate animal carcasses such as fish, seaweed, and shellfish that are suspected of being contaminated, in order to investigate the concentration of substances. As explained above, since the present invention is constructed as described above, it has the following effects. (1) Animal waste contaminated with radioactive substances is stored in a microwave-transparent container, heat is generated from within the waste itself by microwave irradiation, and gases containing water vapor and other substances are extracted from the microwave-transparent container. To obtain a dry object which can be quickly and almost completely dehydrated without generating almost any decomposition gas of organic matter, can be easily sterilized and incinerated in a specific institution, and can be easily stored without spoiling for a considerable period of time. This makes it extremely easy to preserve and incinerate radioactively contaminated animals, which previously required preservation in formalin until handing over to a specific organization and subsequent processing. (2) During microwave irradiation, the gas generated from radioactive animal waste is first cooled with a cooling device and the liquefied liquid is collected in a collection container, so organic matter containing radioactive materials contained in the animal waste can be collected. It can be captured in a collection container. (3) Since the microwave transmission container is provided with an air supply port and air is forcibly introduced into the container, water vapor and other substances generated from radioactive animal waste can be efficiently drawn out through the discharge port.
When microwave irradiation is performed while the inside of a microwave transmitting container is evacuated, there is no risk of plasma generation compared to microwave vacuum heating, which tends to induce plasma inside the container once drying has progressed to a certain extent. (4) Since the residual gas that has not been liquefied out of the gas taken out from the microwave transmission container is led to the oxidizer and subjected to an oxidation reaction, water and carbon dioxide gas that can easily adsorb and remove tritium and carbon-14 that may exist in the residual gas It can be in the form of (5) Since water, carbon dioxide, and other gas obtained after oxidation are adsorbed and removed by the adsorption device, most of the radioactive substances and odors can be stopped within the system, and water is also removed from the exhaust gas from the adsorption device. and tritium and carbon, which may be present in the form of carbon dioxide gas.
Since the radioactive material is captured by a device that captures and removes 14, radioactive material is almost completely prevented from dissipating outside the system, making it possible to ensure complete dehydration of this type of radioactively contaminated animal.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram of an apparatus for implementing the present invention, and FIG. 2 is a diagram showing a partial modification of FIG. 1. DESCRIPTION OF SYMBOLS 10... Decompression housing, 14... Flow rate adjustment device, 20... Microwave generator, 22... Cooling device, 24... Collection device, 26... Oxidizing device, 2
8...Adsorption device, 30...Microwave irradiation chamber, 3
0'...Microwave transparent container, 40...Waste,
43...cold trap, 44...carbon dioxide absorption device, 45...pump.

Claims (1)

[Claims for Utility Model Registration] 1. A microwave irradiation chamber 30 and a microwave transmitting container 30' which is placed in the irradiation chamber and houses a radioactively contaminated animal to be dehydrated; Exhaust port 1 for taking out gas with water vapor and other substances
8' is provided in the microwave transmission container, a cooling device 22 for cooling the gas is connected to the outlet, and a collection container 24 is provided for collecting liquid cooled and liquefied from the gas. It's hot,
An air supply port 16' is provided for forcibly supplying air to the microwave transmission container, and
An oxidizing device 26 for oxidizing residual gas that has not been liquefied by the cooling device is connected to the collection container,
an adsorption device 28 for adsorbing and removing water, carbon dioxide, etc. obtained after oxidation, and a device 43 for capturing and removing tritium and carbon-14 that may be present in the form of water and carbon dioxide in the exhaust gas from the adsorption device; A dehydration device for radioactively contaminated animals, comprising: 44. 2 Claims for registration of a utility model in which the device for capturing and removing tritium and carbon-14 is comprised of a cold trap 43 for collecting tritiated water and a carbon dioxide absorption device 44 for absorbing 14-CO ₂ The dehydration device according to item 1.