JPH04136737A - Dust sampler having dehumidifying power - Google Patents

Abstract

PURPOSE:To increase the amount of dust which can be taken out from a filter at the time of analysis and to improve sharply the efficiency of the analysis by a method wherein the dust caught and collected on the filter is dehumidified and dried. CONSTITUTION:Dust contained in the air sucked into a cyclone 1 is pushed against the inner wall of the cyclone 1 by a centrifugal force and then drops down to the lower part 1b of the cyclone. The dust dropping down in this way is sucked by a pump 5 and caught and collected on a very small area (e.g. of a diameter 5 to 10mm) on an orthogonal type membrane filter 4. After the dust in a desired amount is collected, driving of a blower 7 is stopped and the pump 5 is driven in the state of a solenoid operated valve 8 being closed. Then a tube 2a, a filter holder 3 and a tube 2e are subjected to pressure reduction and put in a state of vacuum. By this state of vacuum being maintained for a prescribed time, the dust on the orthogonal type membrane filter is dehumidified sufficiently.

Description

[Detailed Description of the Invention] <Industrial Application Field> By providing a dehumidifying function without using heating means, the present invention makes it easy to remove dust from the filter during analysis without changing the dust placed on the filter. The present invention relates to a dust sampler having a dehumidifying ability.

<Prior art> Conventionally, samplers that suck a large amount of air at a rate of 1 m3/min, for example, are made of a mesh of fine fibers with low pressure loss, and have a large diameter (for example, an outer diameter of 110 mm).
mm) filter was used. However, such a sampler has the disadvantage that dust gets into the mesh, making it difficult to extract and analyze the dust later. Furthermore, since the dust is dispersed in the large-diameter portion, the dust density on the filter becomes low, making it difficult to analyze.

Therefore, the dust collected by the filter used in such a sampler is not suitable for being separated from the filter by a disperser or the like and analyzed by an elemental analyzer using microwave induced plasma.

On the other hand, filters used for analysis in microwave-induced plasma elemental analyzers and the like have been so-called orthogonal membrane filters, which are made of polycarbonate film with microscopic holes.

However, such a straight-hole type membrane filter has a drawback that it cannot suck in a large amount of air at a rate of, for example, 1 m'/min because of a large pressure loss.

Therefore, the present inventors developed a cyclone that sucks in a large amount of air, a straight-hole membrane filter disposed downstream of the cyclone, and a pump that sucks and discharges a small flow of fluid from the lower part of the cyclone. A straight-hole membrane filter is equipped with a flow meter disposed downstream of the pump, a needle valve that adjusts the flow rate of the flow meter, and a blower that sucks and discharges a large flow of fluid from the upper part of the cyclone. We have developed a dust sampler that collects the dust in the air on a very small area.

However, in such a dust sampler, in order to dehumidify the dust collected on the filter, the filter had to be removed from the sampler and subjected to treatment such as heating. For this reason, not only is the operation complicated, but there are also drawbacks such as the quality of some substances being altered by heating.

<Problems to be Solved by the Invention> The present invention has been made in view of the drawbacks of the conventional examples, and its purpose is to remove the dust collected on the filter from above during analysis without changing its quality. To provide a dust sampler having a dehumidifying function that is easy to take out.

Means for Solving the Problems> The features of the present invention that solve the above problems are that a dust sampler includes a cyclone that sucks in a large amount of air, and an orthogonal membrane disposed downstream of the cyclone. a filter, a pump that suctions and discharges a small flow of fluid from the lower part of the cyclone, a flow meter disposed downstream of the pump, and a needle valve that adjusts the flow rate of the flow meter;
A blower that sucks and discharges a large flow of fluid from the top of the cyclone, a solenoid valve that opens and closes a flow path from the cyclone to an orthogonal membrane filter, and a drive signal that drives the pump and turns on and off the solenoid valve. and a controller that sends an opening/closing signal, and the solenoid valve is closed while the pump is driven to dehumidify the orthogonal membrane filter.

Function> The present invention functions as follows. That is, when a desired amount of dust is captured on a very small area on the orthogonal membrane filter, the controller continues to drive the pump with a drive signal and closes the solenoid valve with an open/close signal. For this reason, tube 2a, filter holder 3. And the tube 2e is depressurized and becomes a vacuum state. By maintaining such a vacuum state for a certain period of time, the dust on the orthogonal membrane filter is sufficiently dehumidified.

<Example> Hereinafter, the present invention will be described in detail using the drawings. 1st
The figure is an explanatory view of the configuration of an embodiment of the present invention, and in the figure, 1 is a cyclone, 3 is a filter holder 4, for example, with an outer diameter of 25 mm.
The pump 2a is a straight hole type membrane filter with a large pressure loss fixed to the filter holder 3, which is a two-knee hollow filter, and 5 is a pump 2a that sucks and discharges a small flow rate of fluid, such as 5j'/min. A tube connecting the filter holder 3 and the pump 5, 6 is a flow meter, 6a is a needle valve that adjusts the flow rate of the flow meter 6, 2b is a tube that guides the fluid discharged from the pump 5 to the flow meter, 7 is, for example, i
2c is a tube that connects the upper part 1a of the cyclone and the blower 7, 8 is a solenoid valve that opens and closes the flow path, and 9 is a pump 5
2d is a tube that connects the lower part 1b of the cyclone and the solenoid valve 8, 2e is a tube that connects the solenoid valve 8 and the filter holder 3. be. still,
The suction flow rate of the pump 5 is adjusted to a desired value by a flow meter (more specifically, a needle valve 6a). Further, as the solenoid valve 8, a one such as a pinch valve that does not hinder the passage of dust is used.

In the embodiment of the present invention having such a configuration, the pump 5 is first activated by the drive signal s1 from the controller 9.
is driven, and the solenoid valve 8 is opened by the opening/closing signal S2. In this state, when the blower 7 is driven, the cyclone 1 moves at a rate of, for example, 1 m'/mi from its inlet 1c.
n. To suck in a large volume of air. The air sucked in in this way moves downward within the cyclone 1 while moving in a circular motion within the cyclone 1, as shown by the broken line in FIG.
The air is then sucked up into the upper part 1a of the cyclone. Moreover, the dust contained in the air sucked into the cyclone 1 is pressed against the inner wall of the cyclone 1 by centrifugal force, and then falls to the lower part 1b of the cyclone.

The dust that has fallen in this way is sucked by the pump 5, passes through the tube 2d-+electromagnetic valve 8→tube 2e, and is deposited onto an extremely small area (for example, 5 to 10 mm in diameter) on the orthogonal membrane filter 4, which has a large pressure loss. is collected by. When a desired amount of dust is captured in this way, the blower 7 is stopped, and the controller 9 continues to drive the pump 5 using the drive signal S1, and closes the solenoid valve 8 using the opening/closing signal S2. In this way, the pump 5 is driven with the solenoid valve 8 closed, so
Tube 2a, filter holder 3, and tube 2e
is reduced in pressure and becomes a vacuum state. By maintaining such a vacuum state for a certain period of time, the dust on the orthogonal membrane filter can be sufficiently dehumidified. When such dehumidification is completed, the driving of the pump 5 is stopped by a drive signal S1 from the controller 9, and the solenoid valve 8 is opened by an opening/closing signal S2.

FIG. 2 is a diagram showing the results of analyzing dust captured by the orthogonal membrane filter 4 using the embodiment of the present invention as shown in FIG. Using a dust sampler (from which the solenoid valve 8 and controller 9 are removed from the device shown in Figure 1), the orthogonal membrane filter 4 is installed.
FIG. 2 is a diagram showing the results of analyzing dust captured by In FIGS. 2 and 3, the horizontal axis represents time, and the vertical axis represents the signal intensity at which the dust component was detected. As is clear from comparing these figures, only 2.5 dust particles are detected per scan (SCAM) in the case of Fig. 3, while only 2.5 dust particles are detected per scan (SCAM) in the case of Fig. 2.
As many as 7.3 pieces of dust were detected per day. Therefore,
It can be seen that when the embodiment of the present invention is used, about three times more dust can be captured than when the conventional example is used.

Note that the present invention is not limited to the above-described embodiments, and can be modified in various ways. For example, the controller 9 in FIG. 1 may be operated manually instead of automatically.
Dust may be directly sucked into the tube 2d from the atmosphere without using the cyclone 1.

<Effects of the Invention> According to the present invention as described in detail above, by dehumidifying and drying the dust collected on the filter, the number of dust that can be taken out from the filter during analysis is more than doubled, greatly improving analysis efficiency. There are advantages to improving it. In addition, when dust sampling is completed, dehumidification is performed in a short time without heating, so there is no need to worry about changes in dust components (chemical reactions, etc.) due to heating, compared to dehumidification using silica gel, etc. This allows for sufficient dehumidification in a short period of time. - Dehumidification can be performed with the orthogonal membrane filter attached to the dust sampler, and there are also advantages such as dehumidification being easier and more efficient than in the conventional example.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram of the configuration of an embodiment of the present invention, and FIGS. 2 and 3 are diagrams showing the results of analyzing dust captured by a filter. 1...Cyclone, 2a-2e...Tube, 4...Orthogonal membrane filter, 5
...Pump, 6...Flowmeter, 6a...
...Needle valve, 7. Old...Blower, 8...
・Solenoid valve, 9...control

Claims (1)

[Claims] A cyclone that sucks in a large amount of air, an orthogonal membrane filter disposed downstream of the cyclone, a pump that sucks and discharges a small flow of fluid from the lower part of the cyclone, and a pump disposed downstream of the pump. a needle valve that adjusts the flow rate of the flowmeter, a blower that sucks in and discharges a large flow of fluid from the top of the cyclone, and an electromagnetic device that opens and closes the flow path from the cyclone to the orthogonal membrane filter. The controller includes a valve and a controller that sends a drive signal to drive the pump and an open/close signal to turn on and off the solenoid valve, and closes the solenoid valve while driving the pump to dehumidify the orthogonal membrane filter. A dust sampler having a dehumidifying ability.