JPH041486Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field] This invention is used to measure the radioactivity concentration in the air at radioisotope handling facilities such as hospitals, universities, and research institutes, nuclear facilities such as nuclear power plants, and the vicinity of these facilities. Regarding radioactive dust samplers.

[Prior Art] A conventional radioactive dust sampler has a configuration as shown in FIG. That is, the filter paper 16 is pulled out from the filter paper drum 10 on which the long filter paper is wound through the rollers 12 and 14, and the filter paper 16 repeats movement and stopping in the direction of arrow A, and is finally wound onto the other drum 18. It will be done.

Further, on the supply side of the filter paper 16 between the rollers 12 and 14, fine particulate radioactive dust floating in the air is sucked and sprayed onto the surface of the filter paper 16, and the radioactive dust is collected on the surface of the filter paper 16. A dust collection unit 20 is arranged, and on the other hand, a detection unit 22 is provided on the winding side of the filter paper 16 for measuring the radioactivity concentration of a radionuclide to be monitored among the radioactive dust collected on the surface of the filter paper 16. It is located.

In addition, in addition to the radionuclides to be monitored, natural radionuclides are also collected on the filter paper 16. Therefore, in order to measure the radionuclides to be monitored with high sensitivity, the travel time of the filter paper 16 from the dust collection section 20 to the detection section 22 is required. The detection unit 22 is arranged at a required distance from the dust collection unit 20 so that the decay time of the natural radionuclide is longer than the decay time of natural radionuclides.

Note that the filter paper 1 from the dust collection section 20 to the detection section 22
Although it is conceivable to slow down the movement speed of the filter paper 16 in order to make the movement time of the filter paper 6 longer than the decay time of natural radionuclides, this has not been done due to a balance with the dust collection time in the dust collection section 20.

In this way, in the conventional radioactive dust sampler, the distance between the dust collection section 20 and the detection section 22 arranged after the dust collection section 20 is set to be long, so the radioactive dust sampler itself has the disadvantage of becoming large. It was hot.

[Purpose of the invention] The present invention was devised in view of the drawbacks of the prior art, and its purpose is to provide a radioactive dust sampler that allows the entire device to be made compact.

[Structure of the device] In order to achieve this objective, the present invention includes a dust collection unit that sucks radioactive dust floating in the air and collects the radioactive dust on a filter paper, and a dust collection unit that is arranged after the dust collection unit. and a detection unit that detects the radioactivity of the radioactive dust collected on the filter paper, and the radioactive dust sampler that moves the filter paper after dust collection to the detection unit to detect the radioactivity, the dust collection unit In order to add a delayed reciprocating path to the movement path of the filter paper from the dust collection unit to the detection unit, a collecting roller is provided to tension the filter paper, and the movement distance of the filter paper from the dust collection unit to the detection unit is set to be long. It is characterized by what it did.

[Embodiment of the invention] A preferred embodiment of the invention will be described below with reference to FIG.

Note that in FIG. 2, the same numbers as in FIG. 1 indicate the same components, and detailed explanations will be omitted.

Guide rollers 24 and 26 for guiding the filter paper 16 are provided on the movement path 100 of the filter paper 16 from the dust collecting section 20 to the detector 22.
Between 4 and 26, the filter paper 16 is pulled out to the left in the figure under tension by the reservoir roller 28. This portion pulled out to the left is a delay reciprocating path 110 added to the moving path 100, and this delay reciprocating path 11
0, even if the dust collector 20 and detector 22 are placed closer than before, the time taken for the filter paper 16 to move between the dust collector 20 and the detector 22 can be made longer than the decay time of natural radionuclides. I can do it.

Further, the reservoir roller 28 is configured to be movable in the directions of arrows C and D, so that the travel time of the filter paper 16 can be changed depending on the object to be monitored. Moreover, as shown in FIG.
The central portion of the filter paper 16 is formed to have a small diameter so as not to come into contact with the dust collection surface 16a of the central portion of the filter paper 16.

As described above, in this embodiment, since the delay reciprocating path 110 is formed in the movement path 100 of the filter paper 16 from the dust collector 20 to the detector 22, the movement time of the filter paper 16 from the dust collector 20 to the detector 22 is reduced. The distance between the dust collector 20 and the detector 22 can be shortened even though the settings are the same as in the conventional case.

In the embodiment described above, the delay reciprocating path 110 is formed to the left of the guide rollers 24 and 26, but the present invention is not limited thereto. The delay reciprocating path may be formed in the opposite direction to that in the above embodiment by using reservoir rollers that are brought into contact at both ends and tension the filter paper 16 from the side opposite to the dust collection surface of the filter paper 16.

Further, the number of accumulation rollers is not limited to one, and a plurality of accumulation rollers may be provided.
0 can be made longer.

[Effects of the invention] As explained above, according to the invention, since a delayed reciprocating path is formed in the travel path of the filter paper from the dust collector to the detector, the travel time of the filter paper from the dust collector to the detector is reduced. Even though the settings are the same as in the past, the distance between the dust collector and the detector can be shortened, which has the effect of making the entire device smaller.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing the main parts of a conventional radioactive dust sampler, Fig. 2 is an explanatory diagram showing an embodiment of the radioactive dust sampler of the present invention, and Fig. 3 is an explanatory diagram showing the collecting roller of the radioactive dust sampler of the present invention. FIG. 16...Filter paper, 20...Dust collection section, 22...Detection section, 28...Storage roller, 100...Movement path, 11
0...Delayed round trip.

Claims (1)

[Scope of utility model registration request] A dust collection unit that sucks radioactive dust floating in the air and collects the radioactive dust on a filter paper, and a detection unit that is placed after the dust collection unit and detects the radioactivity of the radioactive dust collected on the filter paper. In a radioactive dust sampler that includes a section and detects radioactivity by moving a filter paper after dust collection is completed to a detection section, a delay reciprocating path is added to a travel path of the filter paper from the dust collection section to the detection section. 1. A radioactive dust sampler characterized in that the radioactive dust sampler includes a collecting roller provided to tension the filter paper, and a moving distance of the filter paper from the dust collection section to the detection section is set to be long.