JPS63191943A - Transportable dust sampler - Google Patents

Abstract

PURPOSE:To obtain the accurate amount of gas suction without using any external power source by powering on a suction device by a battery device and providing a suction amount integrating device which integrates the amount of sucked gas. CONSTITUTION:When gas to be measured is sucked by a suction blower 1, dust in the gas is deposited on a dust collection filter 5. The gas passed through the blower 1, on the other hand, is integrated by the suction amount integrating device 7, whose value is indicated on an integral value indicator 9 and also compared by a comparator 10 with a suction amount set value set previously in an integrated amount setter 1. When the integrated value of the amount of suction reaches the set value, the comparator 10 sends out a stop signal 13 and a control circuit 12 turns off the circuit of the battery device 16 to stop the suction. At the same time, a suction completion warning device 14 is put in operation. Consequently, the accurate amount of gas suction is obtained without requiring any external power source.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a dust sampler for collecting fine dust suspended in gas, and in particular to a dust sampler for measuring radioactivity concentration in the air. The present invention relates to a dust sampler suitable for use as a device for collecting dust contained in air at a fixed rate.

[Traditional technique]

The concentration of fine dust I suspended in gas has been measured for various purposes. Particularly in nuclear power plants and other places where radiation is handled, it is necessary to measure the radioactivity concentration in the air as one of the important environmental measurement items, so it is necessary to measure the radioactivity concentration in the air. It is often collected and the concentration of radioactivity contained therein is measured using a radiation measuring instrument such as a 0M tube (Geiger tube).

Conventionally, a dust sampler having a gas suction device with a dust collection filter provided on the suction side has been used as a device for collecting this fine dust. This method using a dust sampler measures the radioactivity concentration in the air by measuring the amount of dust in a unit volume of air, that is, the radiation dose at that dust concentration. Amounts must be accurate. For this reason, conventional dust samplers have
Efforts have been made such as providing a suction flow rate control device to control the suction flow rate to a constant level, or adding a timer device to measure the suction time.

When a dust sampler sucks dust from the air for a certain period of time, the dust collection filter naturally becomes clogged due to the accumulation of collected dust, and therefore the pressure loss due to the filter increases as the suction time passes. In order to control the suction flow rate to be constant despite such an increase in pressure loss, a power supply capacity that can sufficiently withstand the increased load on the gas suction device (usually an electric motor and a blower driven by the same) is required. Therefore, conventionally, such flow rate control type dust samplers have been used as AClooV or 2.
It has a built-in gas suction device with a powerful electric motor that is driven by an external 00V power supply.

[Problem that the invention seeks to solve]

However, relying on external power supply in this way
In addition to the inconvenience of having to pull the power cord connected to the dust sampler while taking measurements, there is also the danger of the cord getting tangled with one's feet. Furthermore, there is a problem in that measurements are restricted when measurement points are dispersed over a wide area or in places with poor footing.

Therefore, without supplying power from such an external source,
There was a strong desire for a dust sampler that could obtain an accurate amount of gas suction (accurate dust sample).

[Means for solving problems]

In order to ensure an accurate amount of gas suction, the present invention does not control the suction flow rate (flow rate) at a constant level, but instead of keeping the decrease in suction flow rate due to filter clogging, By measuring the amount of suction and stopping suction when the cumulative amount reaches a predetermined value, it is possible to accurately grasp the amount of suction, and the power consumption of the suction device can be reduced, so the built-in battery device can be used. This was done based on the knowledge that it can be driven sufficiently.

That is, the present invention provides a gas suction device provided with a dust collection filter on the suction side, a battery device for supplying power for driving the suction device, and a suction amount integrating device for accumulating the amount of suctioned gas. The object of the present invention is to provide a portable dust sampler characterized by having the following features.

[Examples and effects]

Next, an embodiment of the portable dust sampler of the present invention will be described based on the drawings.

The drawing is a schematic system diagram of the portable dust sampler of the present invention, and each device shown here is usually housed in a portable case and configured for convenient carrying. In the drawing,
A dust collection filter 5 is provided at the tip of a suction-side piping 4 of a gas suction device 3 that includes a suction blower 1 and a drive motor 2 that drives the blower. Further, a suction amount integrating device 7 is provided on the discharge side piping 6 of the gas suction device 3, and its integrated value signal 8 is inputted to an analog or digital integrated value indicator 9 and a comparator 10. Comparator 1
o compares the set value of the cumulative amount setting device 11 and the cumulative value signal 8, and when the two match, outputs a stop signal 13 for the drive motor 2 to the control circuit 12, and also sends a suction completion warning device such as an indicator light or a buzzer. A suction completion signal 15 is output to 14. These integrated value indicators9. The comparator 1o, its setting device 11, suction completion warning device 14, etc. are provided as necessary, and depending on the purpose, only arbitrary devices can be provided or arbitrary devices can be combined.

The battery device 16 supplies a drive current to the drive motor 2 via the control circuit 12, and the motor 2 is started by a start switch 17.

Next, the operation of the dust sampler shown in the drawings will be explained. After attaching a new dust collection filter 5 to the dust sampler, the drive motor 2 is activated by the activation switch 17 to rotate the suction blower 1 and suck the gas to be measured as shown by the arrow.

Thereby, fine dust floating in the gas is captured by the filter 5 and deposited there over time. On the other hand, the gas discharged from the suction blower 1 is integrated by a suction amount integration device 7 provided on the discharge side piping 6, and the integrated value is indicated by an integrated value indicator 9, and the comparator 10
At this point, the suction amount set value is compared with the suction amount setting value set in advance in the integrated amount setting device 11.

When the integrated value of the suction amount matches the set value, the comparator 10
A stop signal 13 is issued from the stop signal 13, and in response to this signal, the control circuit 12 cuts off the supply current from the battery device 16, stops the drive motor 2, and completes the suction. On the other hand, comparator 10
At the same time, the suction completion signal 15 is output, and the suction completion warning device 1 is activated.
Activate 4.

Note that if only the integrated value indicator 9 is provided without providing an automatic stop means after the comparator 10, the drive motor 2 may be manually stopped based on this indicated value, and the suction completion warning device 14 may be It is also possible to manually stop it by this operation.

In this way, even if pressure loss increases due to dust accumulation on the dust collection filter 5, the suction blower 1 can be operated at a constant rotation speed.
However, since the suction amount itself can be determined based on the suction amount integrated value and the appropriate amount of suction for one time can be determined, there is no problem with accuracy. Rather, unlike in the case of constant flow rate control, an excessive pressure difference is not generated before and after the dust collection filter, so there is an effect that the dust collection efficiency does not decrease.

The dust collection filter used in the present invention may be a filter that is normally used for collecting dust in gases, such as one made of cellulose fiber, glass fiber, or synthetic fiber such as polyester, polyamide, or polypropylene. Examples include woven paper, woven fabrics, non-woven fabrics, etc. The so-called electric left filter is a synthetic fiber with good chargeability or a resin with good chargeability attached around the fiber, which is charged by corona discharge etc.
It is preferable because it also electrostatically adsorbs dust and exhibits high collection efficiency even with low pressure loss. By using such an electret filter, the power consumption of the gas suction device can be significantly reduced, and this effect is particularly exhibited in a portable dust sampler driven by a battery device.

The battery device is preferably one that is light in weight and rechargeable; for example, a nickel-cadmium battery or the like can be used.

A small DC motor can be used as the drive motor for driving the suction blower.

As the suction amount integrating device, for example, a device that integrates the output of a hot-wire type wind speed sensor, a device using a rotary air volume integrating device such as a turbine meter, etc. can be used, but a device with as little pressure loss as possible is preferable.

〔Effect of the invention〕

The portable dust sampler of the present invention uses a battery to supply power to the suction device, and is equipped with a suction amount integrating device that totals the amount of sucked gas. A sample of the amount of suction (or accurate) dust concentration is obtained. Moreover, if an electret filter is used as the dust collection filter, the pressure loss is low and the power consumption of the battery device can be controlled, so that the effects of the present invention can be further exhibited.

The portable dust sampler of the present invention is particularly suitable for measuring radioactivity concentrations in the air at many points, especially in facilities with large areas such as nuclear power plants.

[Brief explanation of the drawing]

The drawing is a schematic system diagram of the portable dust sampler of the present invention. 1... Suction blower 2... Drive motor 3...
・Gas suction device 4... Suction side piping 5... Dust collection filter

Claims (1)

[Claims] 1) A gas suction device (3) provided with a dust collection filter (5) on the suction side, and a battery device (16) for supplying power for driving the gas suction device (3). A portable dust sampler characterized in that it has a suction amount integrating device (7) that integrates the amount of gas sucked. 2) The portable dust sampler according to claim 1, wherein an electret filter is provided as the dust collection filter (5). 3) The gas suction device (3) is configured to be stopped when the integrated value of the suction amount integration device (7) reaches a preset value. Portable dust sampler.