JP3163165U - Air collector - Google Patents

Abstract

To provide an air collection device having a simple structure and capable of accurately obtaining a ratio of fine particles in air from collected air. In an air collection device 1, a reducer pipe 2a is connected to a collection box 2d, and a fan 3 sucks air into the collection box 2d. The air path including the reducer pipe 2a and the collection box 2d is provided with a filter 2c that does not allow fine particle components in the air to pass therethrough. The amount of fine particles adhering to the filter 2c Thus, the ratio of fine particles in the air is obtained. The reducer pipe 2a has a smaller diameter at the air intake port than at the base end side. [Selection] Figure 1

Description

  The present invention relates to an air collecting device used for collecting fine particles contained in air and determining the proportion of fine particles in the air.

  Conventionally, when obtaining the proportion of fine particles contained in the air, a method for collecting fine particles (for example, salt) such as a dry gauze method and a wet gauze method has been employed (Non-Patent Document 1). FIG. 6 is a schematic view showing a conventional method for collecting fine particles. As shown in FIG. 6A, the dry gauze method is a method in which a gauze 7 is attached to a frame member 6 having a 10 cm square square hole, and fine particles are attached to the gauze 7 and collected. As shown in FIG. 6 (b), the wet gauze method is a method in which gauze 7 is wound around a cylindrical member to have a diameter of 2.5 cm and a length of 12 cm. This is a method in which fine particles are attached to the gauze 7 and collected while the 7 is always wet.

  In the method for collecting fine particles disclosed in Non-Patent Document 1, since the gauze 7 serving as a collecting material is exposed to the outside, it is easily affected by, for example, wind and rain, and for example, per unit volume in air. In the case of measuring the proportion of fine particles, etc., there is a problem that the accuracy of measurement results decreases.

  In order to solve this problem, various air collection devices having a configuration in which a particulate collection material (for example, a gauze and a filter) is installed inside the frame have been proposed. Patent Document 1 discloses an air collection device configured to take external air into a chamber by a collection tube and collect fine particles in the taken-in air using a filter installed on the side of the chamber. .

  Patent Document 2 discloses an air collection device configured to collect fine particles in the air by replenishing the air taken into the device with a sprayer to form a mist and recovering it in a liquid. ing. Patent Document 3 discloses an air collection device configured to ionize inorganic impurity components in the air and take them out into a liquid by discharge from a discharge electrode.

  Patent Document 4 discloses an air collection device configured to take air into the device by, for example, a resin tube connected to an air pump. Patent Document 5 discloses a technique that uses a fan installed in an apparatus for sucking air into the apparatus.

JP 2009-198224 A Japanese Patent Laid-Open No. 11-183335 JP 2009-175063 A JP 2009-128054 A JP 2010-124711 A

Port Engineering Research Data No. 784, Port Technology Research Institute, Ministry of Transport, September 1994, pp. 6-8

  However, as described above, in the technique of Non-Patent Document 1, since the gauze 7 serving as a collecting material is exposed to the outside, it is easily affected by, for example, wind and rain, and it is difficult to collect fine particles from the air. There is a problem, and therefore the measurement accuracy such as the content of fine particles is lowered. Further, since the technique of Non-Patent Document 1 is an exposure-type collection method, when collecting a large amount of fine particles to some extent, it is necessary to make the collection time extremely long, and the collection efficiency is poor. There is a point. In particular, in the exposure-type collection method, if the collection location of the fine particles is outdoors, for example, when it rains, the collected fine particles will be washed away, and the measurement will be performed again. Collection efficiency is extremely reduced.

  Also, in the techniques of Patent Documents 1 to 5, since the outside of the apparatus and the inside of the apparatus are connected by a pipe or tube having a constant inner diameter, when these pipe diameters are large, the air from outside the apparatus Due to the inflow, the measurement accuracy of the fine particles is still low. On the other hand, in the case where the inner diameter of the tube or the tube is small, there is a problem that the measurement result becomes uneven due to a narrow area for taking in external air. In particular, in the technique of Patent Document 4 in which a resin tube is used for taking in air, there is a problem that the tube is easily deformed and the measurement accuracy is lowered.

  Furthermore, in the prior arts of Patent Documents 2 to 4, it is necessary to install a sprayer, a discharge electrode, a suction control device, or the like in the device, which causes problems that the structure of the device becomes complicated and the manufacturing cost increases. .

  The present invention has been made in view of such problems, and an object thereof is to provide an air collection device capable of accurately obtaining the proportion of fine particles in the air from the collected air with a simple structure. To do.

  The air collection device according to the present invention is a collection box that takes in air to be analyzed, and the collection box that is installed in the collection box and that has a smaller diameter at the tip air intake port from the base end side. A reducer pipe that is fed into the collection box, a fan that sucks the air into the collection box, and a predetermined fine particle included in the air that is provided in the air path including the reducer pipe and the collection box and is taken in from the reducer pipe And a sensor that measures the amount of air that has flowed through the air path, and the ratio of the fine particles in the air is obtained from the amount of air and the amount of fine particles attached to the filter. To do.

  In the present invention, for example, the filter has a mesh size of 1 to 3 μm.

  For example, the air collection device described above has a pair of clamping members that have holes and clamp the filter at the forehead. In this case, for example, the clamping member is provided in the collection box, and the collection box is provided with a lid for opening and closing, and the filter can be replaced.

  In addition, the air collection device has, for example, a second reducer pipe attached to the collection box, and the fan is connected to the collection box through the second reducer pipe. The reducer pipe 2 has an inner diameter on the fan side larger than an inner diameter on the collection box side. For example, the sensor is preferably provided in the reducer pipe or the second reducer pipe.

  In the above air collection device, for example, the collection box is made of a transparent or translucent material, and the state of the filter can be confirmed from the outside of the collection box.

  In the air collection device according to the present invention, a reducer pipe is installed in a collection box, and air to be analyzed is sent from the reducer pipe into the collection box. The reducer pipe has a smaller diameter at the distal end of the air intake than at the proximal end. Thereby, the taken-in air can be rectified in the area where the reducer pipe is expanded. Therefore, it is possible to prevent the measurement accuracy of the ratio of the fine particles in the air from being lowered due to the influence of the wind from the outside.

  Further, the air path including the reducer pipe and the collection box is provided with a filter that does not allow the permeation of fine particles contained in the air, and by the amount of air measured by the sensor and the amount of fine particles attached to the filter, The proportion of fine particles in the air can be obtained with high accuracy.

  The air collection device of the present invention has a simple structure in which a reducer pipe is installed in a collection box and a filter, a fan, and a sensor are installed, and an increase in manufacturing cost can be suppressed.

It is a side view which shows the air collection apparatus which concerns on embodiment of this invention. It is a perspective view which shows an air collection part. (A) is a front view which shows a fan, (b) is a side view similarly. It is a side view which shows the modification about the air collection apparatus which concerns on embodiment of this invention. It is a figure which shows the performance curve of a fan as an example. (A) is a figure which shows the dry gauze method, (b) is a figure which shows the wet gauze method.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, the structure of the air collection apparatus of this embodiment is demonstrated. FIG. 1 is a side view showing an air collection device according to an embodiment of the present invention. 2 is a perspective view showing the air collecting part, FIG. 3A is a front view showing the fan, and FIG. 3B is a side view of the same. As shown in FIG. 1, an air collection device 1 according to this embodiment includes an air collection unit 2 for collecting analysis target air and a fan 3 for sucking air. .

  As shown in FIG. 2, the air collection unit 2 takes in the air to be analyzed into the bowl-shaped collection box 2 d, and a (first) reducer pipe is provided on each of a pair of opposing side surfaces. 2a, the second reducer pipe 2e is fixed. The air sent from the (first) reducer pipe 2a into the collection box 2d is taken into the fan 3 through the second reducer pipe 2e and then discharged to the outside. A filter 2c is installed in the air path including the (first) reducer pipe 2a and the collection box 2d, and the air taken in from the reducer pipe 2a is transmitted through the filter 2c, whereby a predetermined content contained in the air is contained. Components such as fine particles such as salt in the air are not allowed to pass through the filter 2c. In the present embodiment, a pair of filter attachment plates 2b are provided inside the collection box 2d, and the filter 2c is sandwiched and attached between the filter attachment plates 2b.

  The (first) reducer pipe 2a is provided such that the inner diameter on the air intake side is smaller than the inner diameter on the collection box 2d side. Thereby, the air taken into the pipe can be rectified in the pipe whose diameter is expanded, and the influence of, for example, wind flowing into the inside of the reducer pipe 2a from the outside can be reduced. In the present embodiment, the second reducer pipe 2e also has an inner diameter on the fan 3 side larger than the inner diameter on the collection box 2d side, whereby the second reducer pipe 2e is added to the (first) reducer 2a. The air taken in is also rectified. The first reducer tube 2a has an inner diameter of 50 to 100 mm on the air intake side, for example, and an inner diameter of 100 to 150 mm on the collection box 2d side, for example. The second reducer pipe 2e has an inner diameter on the fan 3 side of, for example, 100 to 150 mm, and an inner diameter of the collection box 2d side of, for example, 175 to 210 mm.

  In the present embodiment, sensors for measuring the amount of collected air, for example, the first pressure sensor 4 and the second pressure sensor 5 are installed in the (first) reducer pipe 2a. . The first pressure sensor 4 is installed, for example, on the tube axis of the reducer tube 2a, and is disposed coaxially with this hole, for example, at a position close to a hole through which air is passed in the filter mounting plate 2b described later. ing. Thereby, the pressure of the air sent into the air collection device 1 by the first pressure sensor 4 can be measured. The second pressure sensor 5 is installed, for example, on the inner wall on the radially outer side of the reducer pipe 2 a at the position of the first pressure sensor 4, so that the second pressure sensor 5 puts it in the air collecting device 1. The static pressure of the air to be taken in can be measured. For example, the differential pressure (dynamic pressure) between the measured value of the pressure by the first pressure sensor 4 and the measured value of the static pressure by the second pressure sensor 5, the specific gravity of the air, the temperature, and the first and second pressures The amount of air taken from the reducer pipe 2a and flowing through the air flow path can be measured based on the flow path area at the position where the sensor is installed. The measurement values obtained by the first pressure sensor 4 and the second pressure sensor 5 are configured to be displayed on, for example, the display device 8 installed outside the reducer pipe 2a.

  The collection box 2d is formed in, for example, a plate-like member, for example, an acrylic transparent or translucent plate material, for example, in a cubic shape having an outer side of 250 mm, and the thickness of the plate material is, for example, 15 mm. By forming the collection box 2d to be transparent or translucent, it is visible from the outside of the collection box 2d. In one of the side surfaces of the collection box 2d, a hole for taking in air is provided, for example, in a circular shape having a size equal to or smaller than the inner diameter of the reducer pipe 2a, and corresponds to the position of this hole. The first reducer tube 2a is fixed. Further, a hole for exhausting air to the fan 3 side is equivalent to the inner diameter of the second reducer pipe 2b on the side face of the collection box 2d facing the side face where the first reducer pipe 2a is installed. The second reducer pipe 2e is fixed in correspondence with the position of the hole.

  Inside the collection box 2d, for example, one of the filter mounting plates 2b is fixed by, for example, a bolt on the side surface where the reducer pipe 2a is installed. Then, the filter 2c is overlaid on this fixed plate, and another filter attachment plate 2b is overlaid thereon, and attached by, for example, bolts, so that the filter 2c is sandwiched and attached between the filter attachment plates 2b. It is configured to be. For example, a circular hole having a size equal to or smaller than the size of the air intake hole on the side surface of the collection box 2d is provided in the pair of filter mounting plates 2b. Filter 2b. And when the air taken in into the air flow path passes through the hole, fine particles larger than the mesh of the filter 2c are attached to the filter 2c and can be collected. This hole is, for example, a circle (for example, 100 mm) having a diameter of 50 to 150 mm, and the size of the filter is, for example, 20 mm or more than the size of the hole of the mounting plate 2b in consideration of the mounting allowance to the filter mounting plate 2b. It is preferable to use a large one (for example, a circle having a diameter of 120 mm). By making the shape of the part to which the fine particles adhere in the filter 2c circular, the fine particles adhere evenly on the filter surface. When the amount of air passing through the unit area of the filter 2c is constant, the portion of the filter 2c to which fine particles adhere is less than 50 mm in diameter, so that the amount of air per unit time passing through the entire surface of the filter 2c is reduced. If the collection time becomes longer and the diameter exceeds 150 mm, the pressing force by the air passing through the entire surface of the filter 2c increases and the filter 2c is easily broken. The size of the hole in the portion (filter mounting plate 2b) to which the fine particles adhere in the filter 2c can be selected as appropriate depending on, for example, the type of the fan 3 described later. That is, for example, by preparing a plurality of types of filter mounting plates 2b having different hole sizes in advance, the area to which the fine particles are attached can be changed according to the hole size. The upper surface of the collection box 2d is configured, for example, as a lid of the collection box 2d, so that the lid can be closed when air is collected, and the lid can be opened when the collection is completed to collect or replace the filter 2c. .

  The filter 2c has, for example, a mesh size of 1 to 3 μm, for example 3 μm. Generally, the gauze 7 used in the dry gauze method and the wet gauze method as shown in FIG. 6 has a mesh width of 700 μm. For example, sea salt particles having a particle size of 250 μm can easily form the gauze 7 mesh. To pass through. Therefore, even when a plurality of gauze 7 are stacked, there is a problem that the capture rate of sea salt particles is lowered and the accuracy of the measured value is lowered. On the other hand, in this embodiment, the filter with a small mesh width for fume collection used at the time of welding is used as a filter, for example. Thereby, the capture rate of fine particles in the air can be improved to improve measurement accuracy, and fine particles can be analyzed with high accuracy.

  The second reducer pipe 2e is provided with a flange portion 2f with an end opposite to the collection box 2d projecting outward in a flange shape, for example, and a fan 3 is connected to the flange portion 2f by, for example, a bolt. It is installed by.

  As shown in FIG. 3, as the fan 3, for example, a centrifugal blower that discharges inhaled air in the radial direction can be used. In addition to the centrifugal blower, an axial flow blower that discharges intake air in the axial direction or a mixed flow blower that discharges obliquely can be adopted as the fan 3. In other words, in the present invention, the fan 3 is appropriately selected and used depending on the amount of air collected per unit time, the type of the filter 2c, and the like. For example, a high-pressure blower fan can be used to increase the intake air volume, and a propeller fan, a sirocco fan, or a combination of both can be used to reduce the size and weight of the fan itself. In the present embodiment, a centrifugal blower is used as the fan 3. The fan 3 includes a fan unit 3a, a drive unit 3b, a power supply unit 3c, and a discharge port 3d. By rotating a fan accommodated in the casing of the fan unit 3a by, for example, a motor of the drive unit 3b, Is sucked in from the axial direction of the fan and discharged from the discharge port 3d. The motor of the drive unit 3b is driven by power taken from the external power supply to the power supply unit 3c by, for example, the power cord 3e.

  Next, the operation of the air collection device according to this embodiment will be described. First, the lid on the upper surface of the collection box 2d is opened, and the filter 2c is installed on the filter mounting plate 2b. That is, in the filter mounting plate 2b fixed to the back surface of the side surface where the reducer pipe 2a is installed, the filter 2c is overlapped in accordance with the position of the hole, and another filter mounting plate 2b is further stacked thereon. For example, it is attached with bolts. Thereby, the filter 2c is clamped and attached between the filter mounting plates 2b. When the installation of the filter 2c is completed, the lid of the collection box 2d is closed.

  Next, the power cord 3e is connected to an external power source so that power can be supplied to the power source section 3c, and the fan 3 is switched on. Thereby, electric power is supplied from the power supply unit 3c to, for example, a motor of the driving unit 3b, and the motor inside the fan unit 3a is rotationally driven by rotating the motor. Then, after the air located in the vicinity of the fan 3 is taken into the fan part 3a, the kinetic energy is given by the fan 3, and the air moves outward in the radial direction of the fan 3, and is discharged from the discharge port. Is done. Therefore, the suction side of the fan 3 temporarily becomes negative pressure. Therefore, the air located in front of the air flows sequentially to the suction port of the fan 3. Thereby, the intake of air by the air collection device 1 is started.

  First, air in the vicinity of the first reducer pipe 2a is taken into the pipe from the suction port of the reducer pipe 2a. And the air taken in in the pipe | tube flows for example in the axial direction of the reducer pipe | tube 2a. In the present invention, the reducer pipe 2a is provided such that the inner diameter on the collection box 2d side is larger than the inner diameter on the air intake side. Therefore, even when the flow of air taken into the pipe is disturbed by, for example, wind and rain outside the apparatus, the air can be rectified by flowing through the pipe whose diameter is increased. Therefore, it is possible to prevent a decrease in analysis accuracy due to external winds and the like.

  The air flowing through the reducer pipe 2 a eventually reaches the position of the first pressure sensor 4. Since the air flowing through the pipe has kinetic energy, the first pressure sensor 4 measures the dynamic pressure of the air by the kinetic energy as a value added to the static pressure, and the measured value is displayed on the display device 8. On the other hand, a second pressure sensor 5 is installed on the radially inner wall of the reducer pipe 2a at the position of the first pressure sensor 4, and the second pressure sensor is connected to the first pressure sensor 4 and the shaft. The static pressure of air at the same position in the direction is measured, and the measured value is displayed on the display device 8. Thereby, the differential pressure (dynamic pressure) between the measurement value by the first pressure sensor 4 and the measurement value of the static pressure by the second pressure sensor 5, the specific gravity of the air, the temperature, and the first and second pressure sensors The amount of air taken in from the reducer pipe 2a can be measured with extremely high accuracy based on the flow path area at the installed position.

  The air flows in the first reducer pipe 2a, for example, in the direction of the pipe axis, and eventually passes through the position of the air intake hole of the collection box 2d, passes through the hole of the filter mounting plate 2b, and permeates the filter 2c. Is done. At this time, fine particles contained in the air are filtered by the filter 2c, and fine particles smaller than the mesh width of the filter 2c do not pass through the filter 2c. And the fine particle which does not permeate | transmit the filter 2c adheres to the filter 2c, for example. In the present embodiment, the size of the mesh of the filter 2c is generally smaller than the mesh width of the gauze used in the dry gauze method and the wet gauze method. Therefore, for example, even if sea salt particles having a particle size of 250 μm try to pass through the filter, the particles are smaller than the mesh width of the filter 2c, so that the particles adhere to the filter 2c without being transmitted through the filter 2c. As a result, in the present embodiment, it is possible to improve the measurement accuracy for fine particles having a small particle size, improve the measurement accuracy, and perform fine particle analysis.

  The air that has passed through the filter 2c enters the collection box 2d and flows through the collection box 2d. When the collection box 2d is made of a transparent or translucent material, the state of the filter 2c can be confirmed from the outside of the collection box 2d. For example, it can be visually recognized from the outside of the collection box 2d whether the filter 2c is not clogged or damaged. For example, when the filter 2c is damaged or the like, the lid on the upper surface of the collection box 2d can be opened and the filter 2c can be replaced, so that the filter 2c is damaged and waits until the collection of the fine particles is completed. There is no need, and a reduction in collection efficiency can be prevented.

  The air flowing through the collection box 2 d enters the second reducer pipe 2 e and flows to the fan 3. Similarly to the first reducer pipe 2a, the second reducer pipe 2e has an inner diameter on the outlet side larger than that on the inlet side. Therefore, the rectifying effect by the first reducer pipe 2a can be further improved.

  The air that has flowed through the second reducer pipe 2e is taken into the fan 3 and, as in the case described above, the kinetic energy is given by the fan 3 and proceeds while rotating outward in the radial direction of the fan 3. It is discharged from the discharge port.

  After such air collecting work is continued for a predetermined time, the collecting work is ended by stopping the motor 3b. Then, the lid on the upper surface of the collection box 2d is opened, and the filter 2c with the fine particles attached is taken out.

  And the ratio of the microparticles | fine-particles in the air in a predetermined place can be calculated | required with the quantity of the microparticles | fine-particles adhering to the taken out filter 2c, and the air quantity measured with the sensor. That is, the total amount of fine particles in the air flowing through the air path is measured by the difference in the weight of the filter 2c before and after the start of measurement, and the ratio of fine particles in the air is obtained by dividing this measured value by the amount of air. Can do. For example, the ratio of specific fine particles such as salt content among the fine particles attached to the filter 2c can also be measured for each fine particle.

  As described above, the air collection device 1 of the present embodiment has a simple structure in which the reducer tubes 2a and 2e are installed in the collection box 2d, and the filter 2c, the fan 3, and the sensors 4 and 5 are installed. Even in the manufacture of the air collection device 1, an increase in manufacturing cost can be suppressed.

  In the present embodiment, the reducer pipe 2a for taking in air has an inner diameter on the outlet side larger than that on the inlet side, and rectifies the taken-in air in the area where the reducer pipe is expanded, It is possible to prevent the analysis accuracy from being lowered due to wind. Furthermore, the amount of air trapped can be measured with high accuracy by the sensor, and the measurement result of the fine particles adhering to the filter, for example, the amount of trapped measurement does not decrease.

  In the present embodiment, the collection box 2d is formed in a cubic shape, but the shape of the collection box 2d is not limited as long as the structure allows air to flow. In this embodiment, the filter mounting plate 2b is installed inside the collection box 2d. However, unless the measurement accuracy of the fine particles by the filter 2c is reduced, the mounting position of the filter mounting plate 2b is the collection position. It may be on the air path outside the box 2d. For example, as shown in FIG. 4, a filter attachment plate 2b is installed between the reducer tube 2a and the collection box 2d. In this case, for example, it is not necessary to install a filter replacement lid on the collection box 2d.

  Furthermore, in the present embodiment, the collection box 2d and the fan 3 are connected by the second reducer pipe 2e. However, as long as the air rectifying effect by the first reducer pipe 2a can be sufficiently obtained, The reducer pipe 2e may be provided in a cylindrical shape, for example, or the collection box 2d may be directly fixed to the fan 3 without installing the second reducer pipe 2e.

  Hereinafter, the Example using the air collection apparatus of this invention is described. First, an air collecting device 1 as shown in FIG. 1 was used, and the size of the portion of the filter 2c exposed to air was a circle having a diameter of 100 mm. As the fan 3, a high-pressure blower fan (manufactured by Yodogawa Seisakusho, model: DH2TL) was used, and as the filter 2c, a glass fiber having a mesh width of 1 μm (manufactured by Nippon Pole Co., Ltd., model: 61638) was used. For reference, FIG. 5 shows a performance curve of the fan 3 used in this embodiment.

  And the air collection time was set to about 24 hours, the collection date and the collection place were changed, and air was collected. And the adhesion amount of the microparticles | fine-particles to the filter 2c was computed by comparing the filter weight before and behind collection. Table 1 below shows the measurement results in this example.

From the examples shown in Table 1, the amount of air collected per unit time is 6.69 to 7.74 m ³ / hour (average 7.23 m ³ / hour), and even when the measurement date and measurement location are different, Measurement results with little variation could be obtained. In particular, Example No. In 10 thru | or 16, all the amount of air collection became equal, and it was able to perform a highly accurate measurement on the same conditions.

  1: air collection device, 2: air collection unit, 2a: (first) reducer pipe, 2b: filter mounting plate, 2c: filter, 2d: collection box, 2e: second reducer pipe, 2f: Flange part, 3: fan, 3a: fan part, 3b: motor, 3c: power supply part, 3d: discharge port, 3e: power cord, 4: pressure sensor, 5: pressure sensor, 6: frame member, 7: gauze

Claims (7)

A collection box for taking in the air to be analyzed;
A reducer pipe that is installed in the collection box and that feeds the air taken in with a smaller diameter at the distal end to the collection box from the proximal end;
A fan for sucking the air into the collection box;
A filter that is provided in an air path including the reducer pipe and the collection box and does not transmit predetermined fine particles contained in the air taken in from the reducer pipe;
A sensor for measuring the amount of air flowing through the air path,
An air collecting device characterized in that a ratio of fine particles in the air is obtained from the amount of air and the amount of fine particles attached to the filter. The air collecting device according to claim 1, wherein the filter has a mesh size of 1 to 3 μm. The air collecting device according to claim 1, further comprising a pair of clamping members that have holes and clamp the filter at a forehead portion thereof. The said clamping member is provided in the said collection box, The lid | cover for opening and closing is provided in the said collection box, The replacement | exchange of the said filter is possible, The filter of Claim 3 characterized by the above-mentioned. The air collection device described. A second reducer pipe attached to the collection box, the fan being connected to the collection box via the second reducer pipe, the second reducer pipe being connected to the fan side; The air collecting device according to claim 1, wherein an inner diameter of the air collecting device is larger than an inner diameter of the collecting box. The air collection device according to claim 5, wherein the sensor is provided in the reducer pipe or in the second reducer pipe. The said collection box is comprised with the transparent or translucent material, The state of the said filter can be confirmed from the outer side of the said collection box, The any one of Claims 1 thru | or 6 characterized by the above-mentioned. The air collection device described.

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