JPS598800B2 - Radiation irradiation method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a radiation irradiation method for irradiating a powder-like object to be irradiated with radiation to improve its properties.

In recent years, with the diversification of industrial fields of use of radiation, materials modified by irradiating particles with radiation are seen as promising, and their industrial value is gradually attracting attention.

However, there are many physical, technical, or equipment-related obstacles to the irradiation method and irradiation apparatus for powdery irradiated objects, and so far no satisfactory irradiation method has been known.

That is, generally when moving a powdery object continuously,
Movement speed tends to vary due to particle size distribution, interparticle friction, etc., and uneven irradiation was observed due to these factors during irradiation.

For example, Japanese Patent Publication No. 50-25507 introduces a method in which particulate organic polymers are suspended in water and then irradiated. However, according to this method, particles with a density higher than that of water will settle, and they will also be exposed to radiation. An increase in water temperature due to energy or the like tends to cause water convection, and there is a possibility that irradiation unevenness is likely to occur due to turbulence in water flow or non-uniformity in flow velocity.

Heat generation due to absorption of radiation energy is a characteristic problem of radiation irradiation. There were drawbacks such as fusion or decomposition of the irradiated object due to heat generation and temperature rise of the belt.

In addition, as is well known as an important issue related to irradiation efficiency,
When an organic polymer material is irradiated in the presence of oxygen, ozone is generated, and the irradiation efficiency decreases mainly due to the radical inhibiting effect of the ozone and oxygen.

In particular, when the object to be irradiated is in the form of a thin film or powder, the contact area with oxygen per unit mass becomes small, and the irradiation efficiency is significantly reduced.

To prevent this, conventionally, for irradiated objects in the form of sheets or coatings, it was necessary to replace the irradiated area with an inert gas, as described in Japanese Patent Publication No. 50-34717, etc. At present, complex irradiation methods and equipment are used in practical use due to gas sealing, etc., and so far, there is no known method for solving this kind of reduction in irradiation efficiency for powder and granular materials.

It is an object of the present invention to provide a radiation irradiation method capable of uniformly and efficiently irradiating a powdery object to be irradiated, which eliminates the drawbacks and problems of the above-mentioned conventional methods.

That is, the gist of the present invention is that, in a method of continuously irradiating a powdery irradiated object with radiation, the irradiated object is mixed with a fluid that wets the irradiated object in a fluid state, and the mixture is mixed with a fluid that wets the irradiated object. The radiation irradiation method is characterized in that the fluid is supplied in a layer onto a moving carrier through which the fluid passes but the object to be irradiated does not pass through, and the radiation is irradiated while the object to be irradiated is moved.

In the present invention, the powder-like irradiated object to be irradiated is a thermoplastic resin, a thermosetting resin, or a powder-like polymer substance mixed with pigment, lubricant, filler, etc., as long as it can be mixed with a fluid. , medicines, foods, grains, inorganic fillers, etc., and there are no particular restrictions on their shape.

Further, as the fluid in the present invention, any liquid having good radiation transparency can be used, but water is generally preferred because it is economical.

In the method of the present invention, the powdery object to be irradiated is mixed with a fluid.

The mixing ratio of the object to be irradiated and the fluid varies depending on the nature, shape, particle size, etc. of the object to be irradiated, but the mixture should have enough fluidity to flow out from a slit-shaped nozzle.

In short, it only needs to flow well. For example, in the case of polyethylene powder under a 50 mesh sieve, the irradiated object 1
The weight ratio of water to water is preferably about 2 to 5.

This mixture is then supplied in a layered manner onto a carrier through which the fluid passes but not the object to be irradiated.

most of the fluid in the mixture is removed through the carrier;
The object to be irradiated is left on the carrier in a layered manner with its outer surface covered with fluid.

It is preferable that the entire surface of the object to be irradiated is covered with the fluid. Therefore, if the object to be irradiated is difficult to wet with the fluid, a small amount of surfactant may be added.

Next, the method of the present invention will be explained in detail with reference to the drawings.

FIG. 1 is a diagram showing an embodiment of the radiation irradiation method of the present invention. In this diagram, 1 is a carrier, which is a net or a carrier through which fluid B can pass, but which does not allow irradiated object A to pass through. The conveying body 1 is composed of a drum having a predetermined width, such as a perforated plate, and is provided to rotate around a shaft 11 at an arbitrary rotational speed.

This carrier 1 is preferably made of metal, particularly stainless steel, from the viewpoint of radiation resistance.

Further, 12 is a fluid guide plate provided inside the carrier 1,
It is provided to be inclined so as to receive the fluid flowing down from above the carrier 1 and guide it below the carrier 1.

Reference numeral 2 denotes a mixture supply pipe, and 3 a slit-shaped nozzle, which supplies a predetermined amount of a mixture C of a powder-like irradiated object A and a fluid B onto the carrier 1 in a predetermined width above the carrier 1. is being done.

Reference numeral 4 denotes an acceleration tube of a radiation irradiator, which is provided so as to irradiate radiation 41 above the carrier 1 onto the irradiated object A that is supplied onto the carrier 1 and transferred.

Further, 5 is a discharge pipe 51 for collecting the irradiated objects A in a saucer.
It is intended to be transferred through

To explain how to irradiate a powdery irradiated object A with radiation using this device, first, a fluid mixture is created by mixing the irradiated object A and a fluid B using a mixer (not shown). Make C.

Then, this mixture C is pumped through the feeding pipe 2 using a fluid conveying device such as a pump, and is supplied from the nozzle 3 onto the moving carrier 1.

At this time, since the carrier 1 is porous such as a net or a perforated plate, the fluid B passes through it and falls onto the fluid guide plate 12 provided inside the carrier 1.

On the other hand, the irradiated objects A mixed and dispersed in the fluid B are placed on the carrier 1 with the outer surface of each irradiated object A wetted by the remaining small amount of the fluid that has passed through the carrier 1. The film is left with a uniform thickness and is transported as the transport body 1 rotates.

The irradiated object A on the carrier 1 is irradiated with the radiation 41 below the acceleration tube 4 which is the irradiation area.

The degree of irradiation can be adjusted by adjusting the transport speed of the carrier 1.

Next, the irradiated object A is placed on the fluid guide plate 1 on the saucer 5.
It is washed away by the fluid B from 2, mixed with the fluid B again, and transported out through the transport pipe 51.

Incidentally, the conveyor 1 may be a rotating endless belt as shown in FIG. 2.

With an endless belt, the length of the upper surface of the belt can be set arbitrarily, so that the flow of fluid B from mixture C supplied onto the belt can be adjusted, and the degree of wetting of irradiated object A with fluid B can be adjusted.

As described above, the radiation irradiation method of the present invention mixes the object to be irradiated with a fluid in a fluid state, and supplies this mixture in a layered manner onto a moving carrier through which the fluid passes but not the irradiation object. , it is possible to form a layer with a uniform thickness on the object to be irradiated in the form of powder particles without scattering or disturbing the layer, and as a result, the object to be irradiated can be irradiated with radiation extremely uniformly. .

In addition, since not only the object to be irradiated but also most of the irradiation device such as the carrier is continuously wetted with the fluid, troubles due to the accumulation of radiation engineering energy are eliminated due to the large heat capacity of the fluid.

In addition, since the surface of the object to be irradiated is thinly covered with fluid and irradiation is performed while continuously cutting off contact with oxygen in the air, there is no need for replacement with inert gas, etc., and no complicated equipment is required. Radiation can be irradiated with high efficiency.

Furthermore, since the object to be irradiated and the fluid are supplied in a mixed state, the apparatus is extremely simple, since the conveying and unloading means only need to be provided with a conduit or the like.

As described above, the method of the present invention solves the problems peculiar to powdery objects to be irradiated, which were difficult in the conventional technology, makes it possible to uniformly irradiate the objects to be irradiated, and eliminates the fusion and scattering of powder particles. Moreover, continuous irradiation with good irradiation efficiency can be obtained without being affected by oxygen, and its industrial significance is extremely large.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are explanatory diagrams each showing an embodiment of the radiation irradiation method of the present invention. A is the object to be irradiated, B is the fluid, C is the mixture, 1 is the carrier, 2
3 is the mixture supply pipe, 3 is the nozzle, 4 is the acceleration tube of the radiation irradiator, and 41 is the radiation.

Claims (1)

[Claims] 1. In a method of continuously irradiating a powdery object to be irradiated with radiation, the object to be irradiated is mixed with a fluid that wets the object in a fluid state, and the mixture is mixed with a fluid that wets the object to be irradiated. A radiation irradiation method characterized by supplying the fluid in a layer onto a moving carrier through which the fluid passes but not the object to be irradiated, and irradiating radiation while moving the object to be irradiated. 2. The radiation irradiation method according to claim 1, wherein the carrier comprises a porous drum. 3. The radiation irradiation method according to claim 1, wherein the carrier is a porous endless belt.