JP4822433B2 - Fine particle classifier and fine particle sampler - Google Patents

Description

  The present invention relates to a microparticle classifier and a microparticle sampler, and more particularly to a microparticle classifier and a microparticle sampler that collect microparticles in a gas.

  Conventionally, a cascade impactor is known as an apparatus for classifying fine particles in a gas. Patent Document 1 discloses a pollen sorting device using such a cascade impactor. FIG. 1 shows a simplified cross-sectional view of a conventional cascade impactor. The cascade impactor of FIG. 1 is composed of a plurality of impactors. Each impactor is a disk-shaped impactor nozzle having a plurality of through holes, a disk-shaped collecting plate having a through hole in the center, and a spacer for ensuring a clearance between the impactor nozzle and the collecting plate. It is configured. In the figure, the impactor nozzle 1, the collecting plate 2 and the spacer 3 constitute one impactor. Further, the impactor nozzle 4, the collecting plate 5, and the spacer 6 that have a smaller opening diameter than the through hole of the impactor nozzle 1 and have a small total opening area of the through holes constitute another impactor. The cascade impactor shown in FIG. 1 is obtained by connecting these two impactors via a spacer 7.

Since the gas is sucked by the suction pump from the collection plate 5 side of the cascade impactor, the gas flows from the through hole of the impactor nozzle 1. The inflowing gas flows as shown by arrows. The gas that has passed through the impactor nozzle 1 flows toward the through hole of the collection plate 2 while changing the direction of motion. At this time, suspended particles that pass through the through-hole of the impactor nozzle 1 together with the gas and cannot follow the movement of the gas due to its inertia collide with the collecting plate 2 without being changed in the moving direction, and are collected. Next, the gas that has passed through the through hole of the collection plate 2 passes through the through hole of the impactor nozzle 4. The gas that has passed through the through hole of the impactor nozzle 4 flows toward the collection plate 5 at a higher flow rate than when it has passed through the impactor nozzle 1. At this time, suspended particles that cannot follow the movement of the gas collide with the collection plate 5 and are collected. The particle size of the suspended particles collected on the collection plate 5 is smaller than that collected on the collection plate 2 in response to an increase in the gas flow velocity. The cascade impactor adjusts the flow velocity of the gas flowing in the cascade impactor according to the number and diameter of the through holes of the impactor nozzle. A plurality of impactors are connected and the flow velocity of the gas is increased in order to collect and classify suspended particles having a small particle size step by step.
JP 2001-183284 A

  The cascade impactor has a structure in which an external gas is sucked by a pressure difference from the outside caused by lowering the internal atmospheric pressure, and a gas flow is generated in the inside. If the gas flow rate is increased in order to classify particles having a small particle size, it is necessary to reduce the diameter of the through hole of the impactor nozzle. For example, in order to cut off particles having a particle size of 0.5 μm or more, a large number of through-holes having an accurate diameter of 0.5 mmφ are provided to cut off particles having a particle size of 0.3 μm or more. This makes it difficult to process the nozzle. For this reason, the conventional cascade impactor has a problem that it is difficult to classify fine particles having a particle diameter of 0.3 μm or less under atmospheric pressure.

  In order to obtain clean air, an air filter has been used as a particle removal and collection device that collects particles in the entire particle size range with high efficiency. However, unlike the cyclone and impactor, the air filter collects particles by various collection mechanisms (inertia, interruption, gravity, electrostatic force, diffusion, etc.), so it is most collected when the filtration speed is constant. There is a difficult particle size (maximum permeation particle size), and for particles of a certain size, there is a filtration rate at which the particle permeates the filter most. For this reason, until now, the focus of filter development has been how to increase the collection efficiency of the maximum permeation particle diameter that is most difficult to collect.

  Furthermore, recently, there are concerns about the effects of ultrafine particles in the atmosphere, particularly particles of 0.1 μm or less, on living bodies. In order to evaluate the effects of fine particles floating in the air on the living body, it is essential to recognize not only the particle concentration for each particle size, but also the relationship between the particle size and the composition of the chemical substances that make up the particle. . As an apparatus for collecting particles of 0.1 μm or less and measuring the composition, there are a reduced pressure impactor and DMA. The decompression impactor needs to depressurize the inlet side to the impactor nozzle in advance, which may cause a change in particle composition. In addition, DMA requires sampling for a long time to collect the amount of particles necessary for chemical analysis, and changes in particle properties due to charge and dilution are also problematic. Therefore, there is a demand for an apparatus that can classify particles of 0.1 μm or less and collect the amount of particles necessary for chemical analysis in a short time.

  It is an object of the present invention to provide a microparticle sampler and a microparticle classifier that can classify microparticles having a particle size on the order of submicrons even under atmospheric pressure, and can collect the amount of particles necessary for chemical analysis in a short time. Objective.

The microparticle sampler of the present invention is a microparticle sampler that collects suspended particles in a gas , penetrates from the upper surface to the lower surface , the upper surface has a larger opening diameter than the lower surface, and the side surface of the through hole is A filter support portion having a through hole whose opening diameter is gradually reduced by a smooth curved inclination, and a fibrous member, provided in the through hole near the lower end of the through hole of the filter support portion , And a fine particle sampling filter arranged in airtight contact with the inner wall of the through hole so as to close the through hole.

  The fine particle sampling filter may be made of stainless fiber.

  The fiber diameter of the fine particle sampling filter may be 1 μm or more.

The microparticle sampler of the present invention is a microparticle sampler that collects suspended particles in a gas , penetrates from the upper surface to the lower surface , the upper surface has a larger opening diameter than the lower surface, and the side surface of the through hole is A filter support portion having a through hole whose opening diameter is gradually reduced by a smooth curved slope, and a breathable porous member, in the through hole near the lower end of the through hole of the filter support portion. A fine particle sampling filter that is provided so as to hermetically contact the inner wall of the through hole and close the through hole.

The through hole of the filter support portion may be formed in a taper shape .

The fine particle classification device of the present invention is a fine particle classification device for classifying suspended particles in a gas according to particle size, classifying the suspended particles, and a coarse particle classifying unit that allows fine particles having a predetermined diameter or less to pass through , A fine particle sampler that collects fine particles up to a minute diameter among floating particles that are connected to the coarse particle classification unit and pass through the coarse particle classification unit, and all ultra fine particles that are not collected by the fine particle sampler And the fine particle sampler penetrates from the upper surface to the lower surface, the opening diameter of the upper surface is larger than the opening diameter of the lower surface, and the side surface of the through hole is a smooth curve a filter support unit with Jo through hole gradually reduced opening diameter by the inclination of, it consists of members of a fibrous, provided in the through hole at the lower end vicinity of the through hole of the filter support unit, through In contact with the inner and airtight, is to anda microparticles sampling filter placed so as to close the through hole.

The fine particle classification device of the present invention is a fine particle classification device for classifying suspended particles in a gas according to particle size, classifying the suspended particles, and a coarse particle classifying unit that allows fine particles having a predetermined diameter or less to pass through , A fine particle sampler that collects fine particles up to a minute diameter among floating particles that are connected to the coarse particle classification unit and pass through the coarse particle classification unit, and all ultra fine particles that are not collected by the fine particle sampler And the fine particle sampler penetrates from the upper surface to the lower surface, the opening diameter of the upper surface is larger than the opening diameter of the lower surface, and the side surface of the through hole is a smooth curve a filter support unit with Jo through hole gradually reduced opening diameter by the inclination of, consists of members of a breathable porous, set in the through-hole in the vicinity of the bottom surface edge of the filter support portion of the through hole Is in contact with the inner wall and airtight through-holes, those having a, a microparticle sampling filter placed so as to close the through hole.

The through hole of the filter support part may be tapered.

  The coarse particle classification unit may have a cascade impactor.

  According to the microparticle sampler of the present invention having such characteristics, microparticles having a particle size of submicron order or less can be efficiently collected even under atmospheric pressure. Further, by using this microparticle sampler in a classifier, submicron order microparticles can be efficiently classified.

(Embodiment 1)
Embodiment 1 of a fine particle classifying apparatus using the fine particle sampler of the present invention will be described below with reference to FIGS.

  FIG. 2 is a cross-sectional view showing the configuration of the fine particle classifier 10 of the present embodiment. The appearance of the fine particle classifier 10 is substantially cylindrical, and is composed of a plurality of members processed into a cylindrical or cylindrical shape.

The fine particle classifier 10 classifies suspended particles (Particulate matter) present in a gas by classifying them according to their particle sizes. For example, the particle size is divided into four categories of 10 μm or more, 2.5 μm to 10 μm, 0.1 μm to 2.5 μm, and 0.1 μm or less. Here, all suspended particles having a particle size of 10 μm or less are represented as PM ₁₀ , all suspended particles having a particle size of 2.5 μm or less are represented as PM _2.5 , and all suspended particles having a particle size of 0.1 μm or less are represented as PM _0.1 .

  In FIG. 2, a fine particle classification device 10 includes a coarse particle classification unit 20 that classifies particles of 10 μm or more and 2.5 μm to 10 μm, and a fine particle sampler that classifies 0.1 μm to 2.5 μm. Unit 30, an ultrafine particle collecting unit 40 that collects suspended particles having a particle size of 0.1 μm or less, and a filter exhaust unit 50. The outer diameters of the classifying parts and the filter exhaust part 50 are substantially the same. A suction pump for sucking gas is attached to the lower part of the filter exhaust part 50.

The coarse particle classification unit 20 has the same configuration as that of the conventional cascade impactor, and includes an impactor for PM _{10 and} an impactor for PM _2.5 . The impactor for PM ₁₀ includes an impactor nozzle 21, a collection plate 22, and a spacer 23. The impactor for PM _2.5 has an impactor nozzle 24, a collection plate 25, and a spacer 26. The impactor for PM ₁₀ and the impactor for PM _2.5 are connected via a spacer 27.

  As shown in FIG. 3, the impactor nozzle 21 is a disk-shaped member, and a plurality of circular through holes are annularly arranged on the surface thereof. Here, as an example, the diameter of the impactor nozzle 21 is 64.9 mm, the thickness is 5 mm, the number of through holes is 18, and the diameter of the through holes is 5 mm. The central axis of each through hole is parallel to the central axis of the impactor nozzle 21, and each through hole is near the center of the radius of the impactor nozzle 21.

  As shown in FIG. 4, the collection plate 22 is a disk-shaped member, and has one circular through hole at the center thereof. Here, as an example, the diameter of the collection plate 22 is 64.9 mm, the thickness is 1 mm, and the inner diameter of the through hole is 30 mm. The central axis of the through hole coincides with the central axis of the collection plate 22.

As shown in FIG. 5, the impactor nozzle 24 is a disk-shaped member, and a plurality of circular through holes are annularly arranged on the surface thereof. Here, as an example, the diameter of the impactor nozzle 24 is 64.9 mm, the thickness is 2 mm, the number of through holes is 36, and the diameter of the through holes is 1.6 mm. The central axis of each through hole is parallel to the central axis of the impactor nozzle 24 , and each through hole is near the center of the radius of the impactor nozzle 24 .

The collection plate 25 is a disk-shaped member, and has one circular through hole at the center. The configuration is the same as that of the collection plate 22.

  The spacers 23 and 26 shown in FIG. 6 are cylindrical members, and are used to secure a clearance between each impactor nozzle and the collecting plate to secure a gas flow path. Each impactor nozzle, the collection plate, and the spacer are arranged in the order shown in FIG. 2, and each connection portion is kept airtight.

  As shown in FIG. 7, the fine particle classification unit 30 is a fine particle sampler, and includes a filter support unit 31 and a filter 32 that classifies 0.1 μm to 2.5 μm fine particles. The filter support portion 31 has a columnar appearance that is thicker than each of the impactor nozzles, the collecting plate, and the spacer, and includes a through-hole 33 in the central portion. The central axis of the through hole 33 and the central axis of the filter support portion 31 are substantially coincident. The opening diameter of the through hole 33 is 30 mm, which is the same as the opening diameter of the collection plate 25, and the slope of the upper side surface of the through hole 33 is a smooth curve so that suspended particles that have flowed in along with the gas do not collide with the side surface. In the lower part, the opening diameter is constant and 10 mm. Note that the filter support portion 31 is connected to the collection plate 25 at an upper portion of the through hole 33 while maintaining airtightness.

  The filter 32, which is a fine particle sampling filter, is composed of a breathable and incompressible fiber filter. In the present embodiment, the filter 32 is an incompressible fiber filter having a thickness of about 4 mm in which, for example, stainless fibers having a fiber diameter of 8 μm are densely entangled to form a felt with a low filling rate. The filter 32 is disposed in the vicinity of the lower end of the through hole 33 so as to block the through hole 33 without any gap, and the surface in contact with the through hole 33 is kept airtight. Since the filter 32 is incompressible, there is almost no volume change even when high-speed gas passes.

  The ultrafine particle collecting unit 40 includes a cylindrical backup filter introduction unit 41, a backup filter 42 that collects suspended particles having a particle size of 0.1 μm or less, and a support porous plate 43 that supports the backup filter 42. . The backup filter introduction part 41 is connected to the filter support part 31 in an airtight manner, and the inside thereof is a cavity having a larger opening diameter than the opening at the lower end of the through hole 33 of the filter support part 31.

  The filter exhaust part 50 has a cylindrical shape, and has a through hole at the center thereof. The filter exhaust part 50 is connected to the support perforated plate 43 in an airtight manner with the through hole directed to the backup filter introduction part 41.

  Hereinafter, the state of classification of suspended particles in the fine particle classification device 10 of the present embodiment will be described with reference to FIG.

[Classification of PM ₁₀ ]
The fine particle classifier 10 classifies suspended particles in the gas by passing a gas containing suspended particles through the inside thereof at a speed of several tens of meters / second at the maximum. In order to cause the gas to flow into the fine particle classifier 10 and generate an air flow, the gas is sucked from the filter exhaust part 50 side. This suction is performed using a suction pump or the like, and the suction speed is, for example, 40 liters / minute.

  When the gas is sucked from the gas outlet of the filter exhaust part 50, the atmospheric pressure in the fine particle classifier 10 becomes lower than the atmospheric pressure, so that the gas flows into the fine particle classifier 10. The inflowing gas first passes through the through hole of the impactor nozzle 21. The gas flow velocity when passing through reaches, for example, 1.886 m / sec.

The gas that has passed through the impactor nozzle 21 flows toward the through hole of the collection plate 22 through clearance by the spacer 23. Since the through-hole of the collection plate 22 is not on the extension of the through-hole of the impactor nozzle 21, the gas flow path that has passed through the impactor nozzle 21 forms a curve as shown by an arrow in FIG. At this time, fine particles of 10 μm or more, which have a large inertia and cannot follow the movement of the curved gas, escape from the gas flow path due to the inertia and collide with the collection plate 22 and are collected. Thus, PM ₁₀ can be classified.

[PM _2.5 classification]
The gas containing PM ₁₀ that has passed through the collection plate 22 flows toward the through hole of the impactor nozzle 24 through the clearance by the spacer 27. The diameter of the through hole of the impactor nozzle 24 is smaller than that of the through hole of the impactor nozzle 21, and the total opening area is also small. Therefore, the flow velocity of the gas that has passed through the through hole of the impactor nozzle 24 is larger than that when it has passed through the impactor nozzle 21. At this time, the flow rate of the gas reaches, for example, 9.211 m / sec.

  The gas that has accelerated through the impactor nozzle 24 flows while bending the flow path toward the through hole of the collection plate 25. At this time, fine particles of 2.5 μm or more that cannot follow the gas motion collide with the collection plate 25 and are collected.

[Classification of PM _0.1 ]
The gas that has passed through the through hole of the collection plate 25 flows into the through hole 33 of the filter support part 31. Since the inflowing gas flows in a direction in which the opening diameter becomes smaller, the gas gradually accelerates and then passes through the filter 32 at a constant speed. During this passage, the filter 32 collects fine particles of 0.1 μm or more in the gas.

The Stokes number Stk and the Peclet number Pe that can be used to select the gas flow rate and fiber diameter when collecting suspended particles using a fiber filter in which fibers such as the filter 32 are layered will be described below. . The Stokes number Stk is a dimensionless value representing the followability of the suspended particles to the gas flow in the fiber filter, and is represented by the following equation.
Stk = Cc · ρp · dp ² · u / (9 μ · df) (1)
Cc is the correction coefficient of Cunningham, ρp is the particle density, dp is the particle diameter, u is the flow velocity, μ is the viscosity coefficient, and df is the fiber diameter of the fiber filter. From the above equation, it can be seen that the Stokes number is proportional to the square of dp (particle diameter) and inversely proportional to df (fiber diameter).

  The Stokes number is also a value affected by u (flow velocity), and the Stokes number increases in proportion to the flow velocity. In other words, as the gas flow rate increases, it becomes impossible to follow the movement of the gas in order from the suspended particles having the larger particle diameter, and the gas flows out of the gas flow path and collides with the fiber of the filter. Thus, by controlling the gas flow rate while referring to the Stokes number and selecting the fiber diameter, the particle diameter of the suspended particles to be collected can be selected. The gas flowing into the through hole 33 does not contain much fine particles having a particle size of 2.5 μm or more. Next, the diameter of the through-hole 33 is selected so that the gas has a speed most suitable for collecting fine particles having a size of 0.1 μm or more.

Since the filter 32 of the present embodiment has a fiber diameter of, for example, about 8 μm, in the Stokes number equation (1) described above, df representing the fiber diameter of the fiber filter is a very small value. As a result, the Stokes number can be increased. However, if the Stokes number is sufficiently large for a fine particle of 0.1 μm or more that is a target of collection, the gas flow rate does not have to be increased as much as when an impactor is used. , PM _0.1 can be classified. However, the filter 32, which is a fiber layer, collects suspended particles not only by the inertia of suspended particles but also by collection mechanisms such as blocking, gravity, electrostatic force, and diffusion.

Here, there is a Peclet number Pe that represents the ratio of the effect of floating particles carried by the airflow and the effect of floating particles carried by diffusion. This Peclet number can be obtained by the following equation.
Pe = u · df / Db (2)

  u is the flow velocity, df is the fiber diameter of the fiber filter, and Db is the diffusion coefficient. Here, in order to reduce the influence of diffusion, it is necessary to increase the Peclet number Pe. The smaller the particle size of the fine particles, the larger the diffusion coefficient Db and the smaller the fiber diameter df, so it can be seen that increasing the flow velocity u is necessary to increase the particle size selectivity.

That is, in the filter 32, the fiber diameter df and the flow velocity u that are most suitable for classifying PM _0.1 are optimized by increasing the Stokes number and the Peclet number. The filter 32 can increase the inertia, suppress the effect of diffusion, and obtain a flow rate necessary for classifying PM _0.1 under atmospheric pressure.

[PM _0.1 collection]
The gas containing suspended particles having a particle size of 0.1 μm or less that has passed through the filter 32 expands in the backup filter introduction part 41, decreases its flow rate, and passes through the backup filter 42. The backup filter 42 collects all fine particles remaining in the gas, that is, mainly suspended particles having a particle size of 0.1 μm or less. The gas that has passed through the backup filter 42 flows out of the fine particle classifier 10 through the filter exhaust part 50.

  As described above, by adding the microparticle sampler of the present invention to the conventional cascade impactor, it is possible to classify particles having a size of 0.1 μm or more, which was difficult to classify with the conventional cascade impactor, under atmospheric pressure. it can.

  Next, the collection efficiency when collecting the fine particles using the fine particle classifying unit 30 of the fine particle classifying device 10 is shown in FIG. 8 for each gas flow rate. In the figure, collection efficiencies for four flow velocities u are shown, with A being 27 m / sec, B being 40 m / sec, C being 53 m / sec, and D being 65 m / sec. This figure shows that the 50% cutoff diameter (the particle diameter at which the collection efficiency is 0.5) can be changed by changing the velocity of the gas flowing into the filter 32. For example, when the flow velocity u is 65 m / sec, the 50% cut-off diameter is 0.09 μm, and at 40 m / sec, the 50% cut-off diameter is 0.193 μm. As shown in this figure, the collection efficiency decreases to zero in each of the curves A to D, which indicates that the transmittance as a filter reaches 100% at this particle size. This point is greatly different from the conventional filter which tried to lower the transmittance.

Further, FIG. 9 shows the collection efficiency when the sidestream smoke of the cigarette is attached to the filter 32 and the suspended particles are collected at a flow rate of 65 m / sec. The amount of the sidestream smoke adhering per unit area is shown. It shows. E in the figure is a graph when sidestream smoke of 0 g / m ² , F is 60 g / m ² , and G is 300 g / m ² is attached. In all cases, the collection efficiency of 0.5 is almost equal to 0.1 μm. In other words, this result indicates that the 50% cutoff diameter of the filter 32 is less susceptible to the amount of suspended particles already collected.

  Next, the relationship between the pressure loss of the filter 32 and the speed at which the gas passes through the filter 32 is shown in FIG. Here, it is shown that the pressure loss when the passing speed is 53 m / sec is a small value of about 10 kPa (75 mmHg), and can be said to be a small value compared to the atmospheric pressure. Since the air permeability of the filter 32 is good, the pressure loss becomes a small value. By using a filter with good air permeability and a small pressure loss in this way, fine particles can be classified using an ordinary pump in accordance with atmospheric changes.

  The diameter of the stainless fiber of the filter 32 is not limited to 8 μm and can be changed depending on the required classification performance. In order to change the particle size of the suspended particles to be collected, a smaller fiber diameter may be used, or a larger fiber diameter may be used depending on the combination with the gas flow rate. FIG. 11A shows the collection efficiency as curves A, B, and C, respectively, when the flow rate is 53.1 m / s and filters with stainless fiber diameters of 4 μm, 8 μm, and 12 μm are used, respectively. As shown in this figure, the 50% cutoff diameter can be reduced by reducing the fiber diameter. FIG. 11B shows that the collecting effect of the filter becomes 0 to 100% by changing the stainless steel fiber diameter df and thickness L of the filter 32 at a flow rate of 53.1 m / s. Curve A is for df = 4 μm, L = 7 mm, curve B is for df = 8 μm, L = 13 mm, and curve C is for df = 12 μm, L = 24 mm. The horizontal axis is the 1/2 power of the Stokes number, but this is proportional to the particle diameter as shown in the equation (1). Here, the curves A, B, and C have particle diameters of 33 nm, 34 nm, and 45 nm at which the effect is 50%, respectively. These can be used as filters in any case. In addition, since manufacture will become difficult if a fiber diameter is less than 1 micrometer, it is preferable to use a fiber diameter of 1 micrometer or more. The thickness of the filter 32 is not limited to 4 mm, and can be changed to one having a thickness of 4 to 40 mm, for example, depending on required classification performance.

(Embodiment 2)
Next, a second embodiment of the fine particle classifying device of the present invention will be described. FIG. 12 shows a fine particle classification unit 70 according to Embodiment 2 of the present invention. FIG. 13 shows a fine particle classification device 80 using the fine particle classification unit 70. In FIG. 13, the configuration other than the fine particle classification unit 70 that is a fine particle sampler is the same as that of the fine particle classification device 10 of the first embodiment. The fine particle classification unit 70 includes a filter support unit 71, a filter 72 that classifies PM _0.1, and a through hole 73.

  The filter support portion 71 has a cylindrical appearance that is thicker than each of the impactor nozzles, the collection plate, and the spacer, and includes a through hole 73 in the center. Furthermore, the outer diameter of the filter support part 71 is the same as that of the coarse particle classifying part 20 and the ultrafine particle collecting part 40. The opening diameter of the through-hole 73 is 30 mm, which is the same as the opening diameter of the collection plate 25 at the top, and the lower end is about 10 mm, and is tapered.

The filter 72 is disposed in the vicinity of the lower end of the through-hole 73 so as to block the through-hole 73 without a gap, and is kept airtight on the surface in contact with the through-hole 73. The material of the filter 72 is the same as that of the filter 32, and is a stainless fiber having a thickness of 4 mm. With this configuration, the filter 72 is also tapered. Even using such a fine particle classification unit 70, PM _0.1 can be classified through the same process as in the first embodiment.

  Here, since the opening diameter of the lower end of the cylindrical portion of the through-hole 73 in the fine particle classification portion 70 is 10 mm, the gas outlet of the through-hole 33 has the same opening diameter as the gas outlet of the through-hole 33 of the fine particle classification portion 30. become. Therefore, in the through holes 33 and 73, the flow velocity of the gas passing through the portion having the opening diameter of 10 mm is the same. However, since the through-hole 73 is tapered, the gas passes through the filter 72 while accelerating. Therefore, since the filter 32 and the filter 72 are made of the same material, the pressure loss of the fine particle classification unit 70 can be made smaller than that of the fine particle classification unit 30.

  In each of the above embodiments, the suspended particles contained in the gas that has passed through the microparticle classifier 10 and the microparticle classifier 80 have a particle size of 10 μm or more, 2.5 μm to 10 μm, and 0.0. It is classified into 4 categories of 1 μm to 2.5 μm and 0.1 μm or less. However, the classification of the fine particle classifier of the present invention may be classified by any category regardless of the above category. Change of opening area of through hole of impactor nozzle and collection plate, change of suction speed of suction pump, change of flow rate of gas flowing in microparticle classifier 10 and microparticle classifier 80, filter 32 and filter 72 The classification of floating particles can be changed by changing the fiber diameter and thickness. For example, by changing the fiber diameter of the filter 33 and the filter 73 or changing the flow velocity of the gas passing through the filter, the lower limit of the particle size of the floating particles classified by the fine particle classification units 30 and 70 is 0.1 μm. For example, the range may be 0.03 μm to 1.0 μm.

  In each of the above embodiments, specific numerical values have been described for the diameter and thickness of each impactor nozzle and the collection plate, the number and diameter of the through holes, and the like. However, the same classification can be performed by designing the impactor nozzle and the collection plate with different numerical values.

  Moreover, although the filter 32 and the filter 72 are made of felt-like stainless steel fibers, other than stainless steel fibers may be used as long as the fiber diameter is uniform and the filling rate is low and the fiber filter is incompressible. For example, a stainless steel fiber mat may be configured by layering metal cloths made of stainless fibers in a mesh shape. Further, a fiber mat may be configured using a metal other than stainless steel, polymer fiber, or the like, and used instead of the filter 32 and the filter 72. Furthermore, the filter 32 and the filter 72 do not necessarily need to be configured by a fiber filter, and may be a porous filter, for example, a filter configured by ceramic. In this case, the porous filter preferably has a uniform pore size and is incompressible.

  In each of the above embodiments, the positions of the through holes of the impactor nozzles 21 and 23 are not necessarily as shown in the drawings. As long as the through holes of the collecting plate do not exist on the extension of the through holes of the impactor nozzle, the through holes may be provided at an arbitrary place.

  In each of the above-described embodiments, the fine particle classification part is added to the cascade impactor. However, the fine particle classification part may be used independently, and the fine particle classification part is connected in cascade, and each fine particle to be classified. You may make it change the particle size of this.

It is sectional drawing which simplifies and shows the structure of the conventional cascade impactor. It is sectional drawing which shows the structure of the fine particle classification apparatus 10 of Embodiment 1 of this invention. It is a block diagram which shows the impactor nozzle 21 of Embodiment 1 of this invention. It is a block diagram which shows the collection plate 22 of Embodiment 1 of this invention. It is a block diagram which shows the impactor nozzle 23 of Embodiment 1 of this invention. It is a block diagram which shows the spacer 23 of Embodiment 1 of this invention. It is a block diagram which shows the fine particle classification part 30 of Embodiment 1 of this invention. It is a graph which shows the result of classifying _PM0.1 using the filter 32 of Embodiment 1 of this invention for every flow velocity of gas. It is a graph which shows the collection result when the secondary flow smoke of tobacco is collected by the filter 32 of Embodiment 1 of this invention with the flow velocity of 65 m / s. It is a graph which shows the pressure loss of the filter 32 of Embodiment 1 of this invention. It is a graph which shows the collection efficiency when the fiber diameter of the filter 32 is changed in Embodiment 1 of this invention. It is a graph which shows the collection efficiency when the fiber diameter and thickness of the filter 32 are changed in Embodiment 1 of this invention. It is a block diagram which shows the fine particle classification part 70 of Embodiment 2 of this invention. It is a block diagram which shows the fine particle classification apparatus 80 of Embodiment 2 of this invention.

Explanation of symbols

10 fine particle classification device 20 coarse particle classification unit 21 PM ₁₀ for the impactor nozzle 22 PM ₁₀ for collecting plates 23,26,27 spacer 24 PM _2.5 for impactor nozzle 25 PM _2.5 for collecting plate 30 fine particle classification unit 31 PM _0.1 Filter support section 32 Filter 33 Through hole 40 Ultra fine particle collection section 41 Backup filter introduction section 42 Backup filter 43 Support perforated plate 50 Filter exhaust section 70 Fine particle classification section 71 PM _0.1 filter support section 72 Filter 73 Through hole 80 Small Particle classifier

Claims (9)

A microparticle sampler that collects suspended particles in gas,
A filter support portion having a through hole penetrating from the upper surface to the lower surface, the opening diameter of the upper surface being larger than the opening diameter of the lower surface, and the side surface of the through hole gradually reducing the opening diameter by a smooth curved inclination ;
Fine particle sampling, which is composed of a fibrous member, is provided in the through hole in the vicinity of the lower end of the through hole of the filter support part, and is arranged so as to close the through hole in airtight contact with the inner wall of the through hole And a fine particle sampler.   The microparticle sampler according to claim 1, wherein the microparticle sampling filter is made of a stainless fiber.   The microparticle sampler according to claim 2, wherein a fiber diameter of the microparticle sampling filter is 1 µm or more. A microparticle sampler that collects suspended particles in gas,
A filter support portion having a through hole penetrating from the upper surface to the lower surface, the opening diameter of the upper surface being larger than the opening diameter of the lower surface, and the side surface of the through hole gradually reducing the opening diameter by a smooth curved inclination ;
It is composed of a breathable porous member, is provided in the through hole in the vicinity of the lower end of the through hole of the filter support part, and is arranged so as to close the through hole in airtight contact with the inner wall of the through hole. A microparticle sampler comprising: a microparticle sampling filter. The microparticle sampler according to any one of claims 1 to 4, wherein the through hole of the filter support portion is formed in a tapered shape . A fine particle classifier for classifying suspended particles in a gas according to particle size,
Classifying suspended particles, and a coarse particle classification unit that allows fine particles having a predetermined diameter or less to pass through ,
A fine particle sampler connected to the coarse particle classification unit and collecting fine particles up to a finer diameter among the suspended particles that have passed through the coarse particle classification unit ,
An ultrafine particle collecting part for collecting all ultrafine particles not collected by the fine particle sampler,
The microparticle sampler is
A filter support portion having a through hole penetrating from the upper surface to the lower surface, the opening diameter of the upper surface being larger than the opening diameter of the lower surface, and the side surface of the through hole gradually reducing the opening diameter by a smooth curved inclination ;
Fine particle sampling, which is composed of a fibrous member, is provided in the through hole in the vicinity of the lower end of the through hole of the filter support part, and is arranged so as to close the through hole in airtight contact with the inner wall of the through hole And a fine particle classifier. A fine particle classifier for classifying suspended particles in a gas according to particle size,
Classifying suspended particles, and a coarse particle classification unit that allows fine particles having a predetermined diameter or less to pass through ,
A fine particle sampler connected to the coarse particle classification unit and collecting fine particles up to a finer diameter among the suspended particles that have passed through the coarse particle classification unit ,
An ultrafine particle collecting part for collecting all ultrafine particles not collected by the fine particle sampler,
The microparticle sampler is
A filter support portion having a through hole penetrating from the upper surface to the lower surface, the opening diameter of the upper surface being larger than the opening diameter of the lower surface, and the side surface of the through hole gradually reducing the opening diameter by a smooth curved inclination ;
It is composed of a breathable porous member, is provided in the through hole near the lower surface end of the through hole of the filter support part, and is arranged so as to close the through hole in airtight contact with the inner wall of the through hole And a microparticle sampling device. The fine particle classifier according to claim 6 or 7, wherein the through hole of the filter support portion is tapered .   The said coarse particle classification part is a fine particle classification apparatus of any one of Claims 6-8 which has a cascade impactor.

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