JP6252831B2 - Particle size distribution measuring instrument - Google Patents

Description

  The present invention relates to a particle size distribution measuring device, and more particularly to a device for measuring the particle size distribution of suspended particulate matter in a gas.

  Patent Document 1 proposes a classifier that classifies and collects fine particulate matter having a particle size of 2.5 μm or less, which is one of air pollutants, so-called PM2.5 (Particulate Matter 2.5). ing. The classifier according to this proposal is configured by mounting an impactor (inertial collision classifier) equipped with a porous jet nozzle above a widely used normal high volume air sampler.

  The classifier according to the above proposal will be further described. In this classifier, a top plate having a plurality of jet nozzles is provided above a normal type high volume air sampler. The collision plate is provided at a position away from the lower surface position of the top plate by a predetermined distance, and the collision collecting material is provided on the upper surface of the collision plate.

  When the classifier according to the above proposal applies a suction force to a normal high-volume air sampler using a pump, the flow of air flowing in from the jet nozzle of the top plate is bent by the collision plate, and particles with a large particle size are The particles are classified away from the flow without being bent due to inertia, and the classified particles are collected by a collision collecting material provided on the upper surface of the collision plate.

  The classifier according to the above proposal is a classifier having one impactor. However, as shown in Patent Document 2, a cascade impactor classifier having a plurality of impactors has been proposed. In this cascade impactor classifier, the aerodynamic particle size of each stage of the impactor is determined to a predetermined value, so that the suspended particulate matter present in the gas can be classified for each particle size. . In the cascade impactor classifier according to this proposal, each particle of 10 μm or more, 2.5 μm to 10 μm, 0.1 to 2.5 μm, or 0.1 μm or less can be classified.

  In the actual device of the particle size distribution measuring instrument that measures the particle size distribution of suspended particulate matter in the gas using a classifier equipped with an impactor as in the above proposal, the top of the measuring instrument body corresponding to the sampling gas intake is protected. At the same time, in order to ensure a uniform flow rate of the sampling gas, a guide portion having a truncated cone shape with a so-called outer shape that is open at the top and expands toward the bottom is provided.

Utility Model No. 3158839 JP 2008-70222 A

However, the conventional particle size distribution measuring instrument for measuring the particle size distribution of the suspended particulate matter has a drawback that it cannot be installed in a narrow place where sufficient space is not provided above the opening of the guide portion.
In addition, the conventional particle size distribution measuring instrument has a problem that it cannot measure suspended particulate matter in the gas flowing in the horizontal direction because the opening of the guide portion must be installed upward and sampling gas must be taken in. was there.

  Therefore, the present invention has been made in view of the above-described problems, and is not limited to the installation location, and further provides a particle size distribution measuring device capable of measuring suspended particulate matter in a gas flowing sideways. The purpose is to do.

In order to achieve the above object, a particle size distribution measuring instrument according to the present invention includes a sensor body configured by mounting an impactor, and a particle size distribution having a guide portion on a gas introduction side containing suspended particulate matter to the sensor body. a measuring instrument, the inner surface of the guide portion forms a cone shaped portion for forming a space of cone shape, the cone-shaped section, set the vertical angle is less than 30 degrees at the top of the cone-shaped And a tube connecting jig portion for mounting a tube for sucking gas is provided on the top side of the cone-shaped portion , and the gas sucked into the tube passes through the tube connecting jig portion. To the center of the circle at the bottom of the conical space .

  In the particle size distribution measuring instrument according to the above configuration, a conical space is formed in the guide, and the shape of the space is such that gas flows from the top of the conical shape toward the center of the circle at the bottom of the conical shape. When supplied, the supplied gas can be uniformly dispersed when it reaches the bottom. Therefore, gas can be uniformly supplied to the impactor provided facing the bottom of the cone shape.

In the particle size distribution measuring instrument according to the present invention, it is preferable that the tube connecting jig portion has a tube insertion portion corresponding to the hole diameter of the tube.

In this case, it can change into the tube connection jig part which has the tube insertion part matched with the magnitude | size of the hole diameter of a tube.

  In the particle size distribution measuring instrument according to the present invention, it is preferable that the tube connecting jig part is formed so as to be separable while forming a part of the guide part.

  In this case, since the tube connecting jig portion is separable, the tube connecting jig portion can be used as necessary.

  In the particle size distribution measuring instrument according to the present invention, it is preferable that the sensor body configured by mounting the impactor is a cascade impactor type in which a plurality of impactors are mounted.

  Since the particle size distribution measuring device according to the above configuration can be a cascade impactor type, a desired particle size distribution can be measured by selecting the number of stages.

In the particle size distribution measuring instrument according to the present invention, a conical space is formed in a guide provided at the top of the sensor body, and the shape of the space is changed from the top of the conical shape to the center of the circle at the bottom of the conical shape. When the gas is supplied toward the bottom, the supplied gas can be uniformly dispersed when the gas reaches the bottom, so that the gas is uniformly supplied to the impactor provided facing the bottom of the cone. Can be supplied.
Therefore, since it can measure even if it connects a tube to the tube connection jig part provided in the top part side of a cone shape, the installation place of a sensor main part is not limited, but a particle size distribution can be measured. In addition, since the tip of the tube can be pointed arbitrarily, for example, it is possible to easily measure even the air flowing sideways.

It is the front view which showed the left half of the particle size distribution measuring device by embodiment of this invention in the cross section. It is a longitudinal cross-section of the guide part of the particle size distribution measuring device shown in FIG. It is a top view of the guide part of the particle size distribution measuring device shown in FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to this embodiment, and constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same. .

  As shown in FIG. 1, the particle size distribution measuring instrument A according to the embodiment of the present invention includes a sensor body 1 and a guide unit 10.

  The sensor body 1 is configured in the same manner as a known cascade impactor classifier. That is, the sensor body 1 is formed in a cylindrical shape having an outer shape of a predetermined height, and the cylindrical shape is divided into a plurality of stages in the height direction.

  The base portion 2 corresponding to the bottom of the cylindrical shape is an upper opening and is formed of a bottomed cylinder, and a suction pipe 2a for sucking gas in the cylinder is provided on a part of the side wall. The cylindrical shape above the base 2 is formed into a plurality of classification stages. In the example shown in the figure, the uppermost stage is the 0th stage classification unit 3a, and below the 0th stage classification unit 3a, there are formed eight classification stages up to the seventh stage classification unit 3h in order. A backup filter stage 3 i is formed between the lowermost seventh stage classification unit 3 and the base 2.

  Each classifying part of the 0th stage classifying part 3a to the 7th stage classifying part 3h and the backup filter stage 3i form a ring-shaped body having the same shape, and are configured to be stacked while being positioned. And these ring-shaped bodies are comprised so that it can laminate | stack while positioning on the base 2. As shown in FIG.

  A perforated plate 4 and a collision plate 5 are provided in each of the classifying parts of the 0th stage classifying part 3a to the 7th stage classifying part 3h. The perforated plate 4 is provided so as to cover the vicinity of the bottom of the ring-shaped body of each classifying portion, and the collision plate 5 is respectively provided so as to cover the ring-shaped body while maintaining a predetermined distance below the perforated plate 4. Is provided. A backup filter 6 is provided at the bottom of the ring-shaped body of the backup filter stage 3i so as to cover the bottom of the ring-shaped body.

  The hole diameter (nozzle diameter) opened in the perforated plate 4 provided in each of the 0th stage classification unit 3a to the 7th stage classification unit 3h is a suspended particulate material (hereinafter referred to as “aerosol”) classified by each classification unit. It is determined by the particle size. That is, the particle diameter of the aerosol classified by the perforated plate 4 becomes smaller as the flow velocity passing through the hole becomes faster, so that the pore diameter of the perforated plate 4 of the 0th stage classification portion 3a for classifying the aerosol having the largest particle diameter is the largest. It is set so that the hole diameter becomes larger in order toward the seventh stage classification portion 3h.

  The collision plate 5 provided on the lower side of the perforated plate 4 in each classifying section receives the gas flowing down from the holes of the perforated plate 4 and converts the received gas into the outer peripheral direction of the plate surface to flow. Have. Further, although not shown in the figure, a collision collecting material is provided on the upper surface of each collision plate 5, so that the aerosol that has a large particle size and cannot be bent due to inertia is separated from the flow by the collision collecting material. It is configured to be able to.

  Around the collision plate 5 provided in each of the 0th stage classification unit 3a to the 7th stage classification unit 3h and the ring-shaped body of each classification unit holding the collision plate 5, the upper surface side of the collision plate 5 A passage (not shown) for allowing gas to pass from the bottom to the bottom is provided. The left arrow in FIG. 1 represents the passage state of the gas. Therefore, the gas can be made to flow in order from the 0th stage classification unit 3a to the 7th stage classification unit 3h.

  In the illustrated sensor body 1, the hole diameter and the backup filter 6 opened in the perforated plate 4 provided in the above-described 0th stage classification unit 3a to 7th stage classification unit 3h classify and collect aerosols having a particle size in the following range. It is decided to be able to gather. That is, the 0th stage classification unit 3a is 11 μm or more, the first stage classification unit 3b is 7.0 μm to 11 μm, the second stage classification unit 3c is 4.7 μm to 7.0 μm, and the third stage classification unit 3d is 3.3 μm. To 4.7 μm, the fourth stage classification unit 3 e is 2.1 μm to 3.3 μm, the fifth stage classification unit 3 f is 1.1 μm to 2.1 μm, the sixth stage classification unit 3 g is 0.65 μm to 1.1 μm, The seventh stage classification unit 3 is determined so as to collect and collect 0.43 μm to 0.65 μm, respectively, and the backup filter 6 of the backup filter stage 3 i provided below the seventh stage classification unit 3 h is 0. It is determined to be able to collect aerosols less than .43 μm.

  As described above, while the sensor body 1 is positioned on the base portion 2, the classification parts of the 0th stage classification part 3 a to the 7th stage classification part 3 h and the backup filter stage 3 i are made airtight with a packing member interposed therebetween. The laminated body is configured so as to be stacked and held by a clamping member (not shown) that is spanned between the base portion 2 and a guide main body 11 of a guide portion 10 described later. Therefore, if this clamping member is removed, the classifying parts of the 0th stage classification part 3a to the 7th stage classification part 3h and the backup filter stage 3i can be easily separated.

  The guide unit 10 includes a guide main body 11 and a tube connecting jig unit 12. The guide unit 10 is provided in the upper part of the sensor main body 1 and has a conical space S formed therein.

  The guide main body 11 is configured in the same manner as a truncated cone-shaped guide portion provided in a known cascade impactor classifier. That is, as shown in FIG. 2, the guide body 11 has a so-called outer cone shape in which the upper part opens and expands toward the lower part in a truncated cone shape. A part of the lower side of the conical space S is formed inside the guide body 11. In the illustrated example, the proportion of the space S formed inside the guide body 11 occupies most of the space S.

  The lower outer peripheral portion of the guide body 11 is configured to be positioned and placed on the ring-shaped body of the 0th stage classification portion 3a that is the uppermost stage of the sensor body 1. Therefore, the lower part of the guide body 11 is opened so as not to cover the upper part of the porous plate 4 of the 0th stage classification part 3a.

  The opening size (opening area) of the upper portion of the guide main body 11 is such that the gas taken in from the upper opening of the guide main body 11 is not attached to the upper portion of the guide main body 11. The flow is determined so as to be able to flow uniformly into each hole of the porous plate 4 of the 0th stage classification unit 3a. Therefore, when the size of the opening at the top of the guide body 11 is determined, the height of the guide body 11 is inevitably determined.

  As shown in FIGS. 2 and 3, the tube connecting jig portion 12 is provided on the upper portion of the guide main body 11, the lower side is formed on the connecting portion 12a, and the upper side is formed on the tube inserting portion 12b. Yes. The remaining space portion of the conical space S is formed in the connection portion 12a.

  The connection between the tube connecting jig portion 12 and the guide main body 11 will be described. On the lower outer periphery of the tube connecting jig portion 12, a flange 12c corresponding to the thick portion 11a provided on the upper outer periphery of the guide main body 11 is provided. Is provided. Around the flange 12c, a plurality of (four in the illustrated example) holes for screws 13 are provided at equal intervals, and the upper surface of the thick portion 11a of the guide body 11 is provided on the flange 12c. Screw holes corresponding to the positions of the formed holes are provided. Accordingly, when the flange 12c is placed on the upper surface of the thick portion 11a and the screw 13 is tightened from the hole of the flange 12c, the tube connecting jig portion 12 and the guide body 11 are kept airtight. The tube connecting jig portion 12 can be easily removed from the guide body 11 by removing the screw 13.

  A through hole having a predetermined diameter communicating with the top of the conical space S formed in the tube connection jig portion 12 is formed in the tube insertion portion 12b located at the top of the tube connection jig portion 12. ing. The axial direction of the through-hole is determined so as to be on the axial line connecting the apex of the conical space S and the center position of the conical circle. The hole diameter of the through hole is determined by the hole diameter of a flexible tube T (see FIG. 1) made of synthetic resin or the like that is inserted into the outer periphery of the tube insertion portion 12b. The hole diameter is adapted to the inner diameter of a 13 mmφ tube (pipe) widely used for liquids.

  According to the experiment under normal measurement conditions in which the hole diameter in the tube insertion portion 12b is 13 mmφ and the suction flow rate is 28.3 L / min, the apex angle θ of the space S having a cone shape is It has been found that if it is 30 degrees or less, the gas supplied through the tube insertion portion 12b can be made to uniformly flow into each hole of the porous plate 4 of the 0th stage classification portion 3a. When the apex angle θ is 30 degrees, the low angle of the space S having a conical shape is 75 degrees. In this case, the smaller the apex angle θ, the more uniformly the gas can be caused to flow into the holes of the perforated plate 4 of the 0th stage classification unit 3a. Since the size is increased, the apparatus can be reduced in size when the apex angle θ is set to 30 degrees.

  In addition, when the gas supplied through the tube insertion part 12b cannot be made to flow uniformly into each hole of the porous plate 4 of the 0th stage classification part 3a, for example, the above-mentioned apex angle θ is more than 30 degrees. When it is larger, the flow velocity of the holes in the perforated plate 4 immediately below the tube insertion portion 12b becomes faster than the holes in the other portions, and is smaller than the particle size planned in the 0th stage classification portion 3a. Diameter aerosols are also collected. In the illustrated example, the 0th stage classification unit 3a collects aerosol of 11 μm or more, but gas is not uniformly supplied to each hole of the perforated plate 4, and the flow velocity is higher than specified in some holes. Becomes faster, aerosols of 11 μm or less are collected, and accurate particle size distribution measurement is impaired.

  As is clear from the above description, the shape of the conical space S formed in the guide portion 10 of the particle size distribution measuring instrument A according to the present embodiment is the shape of the conical body from the top of the conical shape. It is determined that the gas supplied toward the center of the circle at the bottom of the gas is uniformly dispersed when the gas reaches the bottom.

  In the particle size distribution analyzer A having the above-described configuration, when the suction pipe 2a is sucked by a pump (not shown) at a predetermined suction flow rate, the atmosphere including the aerosol taken in from the tip of the tube T passes through the space S in the guide unit 10. Through the perforated plate 4 of the 0th stage classification unit 3a. Next, the air sequentially flows through each of the 0th stage classification unit 3a to the 7th stage classification unit 3h and the backup filter stage 3i. In the middle of the flow, the aerosol in the atmosphere is classified at each stage. After the classification process for a predetermined time, the aerosol collected at each stage is weighed and the particle size distribution is measured. Moreover, the aerosol collected as needed is used as a sample for chemical analysis or the like.

(Experimental example)
A comparative experiment was conducted between the collection of the aerosol according to the present invention including the guide portion 10 having the tube connection jig portion 12 and the conventional aerosol collection with the tube connection jig portion 12 removed from the guide portion 10. It was.

  In the experiment, the apex angle θ (see FIG. 2) of the space S having a cone shape is 30 degrees, the hole diameter in the tube insertion portion 12b is 13 mmφ, and the suction flow rate is 28.3 L / min. The standard particles used are three kinds of powders for JIS testing. The sensor body 1 has a four-stage configuration, the 0th stage classification section is 11 μm or more, the first stage classification section is 7.0 μm to 11 μm, the second stage classification section is 4.7 μm to 7.0 μm, and the third stage classification. The part is determined to be able to collect aerosol of 3.3 μm or less, and the backup filter of the stage for the backup filter is 3.3 μm to 4.7 μm. The measurement is performed by the weight increase amount of the collision plate made of the glass plate at each stage. The experimental results are shown in Table 1.

  As shown in Table 1, the result of the t test is p> 0.05 at any level, and it can be determined that there is no significant difference at the significance level of 5%. Therefore, it can be seen that the particle size distribution measurement similar to that of the conventional type can be performed even when the tube connecting jig portion 12 is attached.

  As is clear from the above experimental results, the tube T can be connected to the tube connecting jig portion 12, and therefore the particle size distribution measuring instrument A can be placed in the atmosphere where the tip of the tube T is to be measured. Therefore, the installation location of the sensor body 1 is not limited, and the sensor body 1 has a feature that it can be easily measured even in the air flowing sideways. Furthermore, since the tube connecting jig portion 12 is separable, it can be used as necessary.

As mentioned above, although preferred embodiment of this invention was described referring an accompanying drawing, it cannot be overemphasized that this invention is not limited to the said embodiment. Various shapes, combinations, and the like of the constituent members shown in the above-described embodiments are examples, and various modifications can be made based on design requirements and the like without departing from the gist of the present invention.
For example, in the above-described example, the guide portion 10 can separate the guide main body 11 and the tube connecting jig portion 12, but they may be integrated.

Moreover, the tube connection jig part 12 can be suitably changed into the tube insertion part 12b according to the magnitude | size to the hole diameter of the tube T. FIG. For example, the tube connecting jig portion 12 may be separated from the guide main body 11, or only the tube inserting portion 12b can be separated from the connecting portion 12a by an appropriate attaching / detaching means. It may be changed.
Furthermore, in the above-described example, the sensor body 1 has an eight-stage configuration. However, the sensor main body 1 may have a four-stage configuration shown in the experimental example or another multistage type.

A particle size distribution measuring device S space T tube 1 sensor main body 2 base 2a suction pipe 3a to 3h 0th stage classification part to 7th stage classification part 3i stage for backup filter 4 perforated plate 5 collision plate 10 guide part 11 guide main body 11a Thick part 12 Tube connection jig part 12a Connection part 12b Tube insertion part 12c Flange 13 screw

Claims (4)

A particle size distribution measuring instrument having a guide part on the side of introduction of a gas containing a suspended particulate matter to the sensor body and the sensor body that is equipped with an impactor,
Inner surface of the guide portion forms a cone shaped portion for forming a space of cone shape,
The cone-shaped portion, the apex angle at the top of the cone shape is set below 30 degrees,
On the top side of the cone-shaped portion , a tube connecting jig portion for mounting a tube for sucking gas is provided ,
The gas sucked into the tube is supplied from the top to the center of a circle at the bottom of the conical space through the tube connecting jig, and the particle size distribution measuring instrument. The particle size distribution measuring instrument according to claim 1, wherein the tube connecting jig portion has a tube insertion portion corresponding to a hole diameter of the tube.   3. The particle size distribution measuring instrument according to claim 1, wherein the tube connecting jig part forms a part of the guide part and is separable. 4.   4. The particle size distribution measuring device according to claim 1, wherein the sensor main body configured by mounting the impactor is a cascade impactor type in which a plurality of impactors are mounted. 5.

Images