JP2008256363A - Device for measuring continuous falling dust - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a device for measuring continuous falling dust, having proper correlation with the measured value of the dust-falling speed to a deposit gauge, capable of measuring the dust-falling speed in a short cycle, and being capable of continuously measuring particle size distribution. <P>SOLUTION: The device for measuring continuous falling dust includes a funnel-shaped particle-sampling port; a blower or compressor for sucking particles in the atmosphere present in the particle-sampling port along with the atmosphere, with the classifier being provided to the rear stage of the particle-sampling port for classifying the particles in the atmosphere sucked from the particle-sampling port into coarse particles and fine particles, the particle counter being provided to the rear stage of the coarse particle outflow port of the classifier for continuously measuring the number of the particles in the atmosphere passing per fixed time or both the number and the size of the particles in the atmosphere; an air-low channel for exhausting the suctioned atmosphere to the open air; an air-flow channel for introducing the atmosphere, of which the flow rate is same to that the atmosphere suctioned from the lower end of the particle sampling port, into the particle-sampling port and a discharge compressor or blower for introducing the atmosphere into the air-flow channels. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an apparatus for measuring a dust falling speed of falling dust in the atmosphere.

  Dust in the atmosphere generated by various production and consumption activities is regarded as one of the serious environmental pollution items, and the actual situation and countermeasures are strongly demanded from society. It is important to develop and manufacture an accurate dust measurement device to understand the actual state of atmospheric dust. In particular, when formulating specific environmental measures, it is effective to search for problem areas by combining specific weather conditions and corresponding measurement values of atmospheric dust in a short period of time. It is necessary to measure dust in the atmosphere for at least 1 hour, preferably within a short period of about 1 to 10 minutes.

  The most reliable method for measuring the dust falling speed of the falling dust is a method in which an adhesive tape having a certain size is placed on the ground surface for a certain time and the properties of the dust particles adhering thereto are measured. The method for measuring the properties of dust particles is to separate the particles adhering to the adhesive tape with a drug, etc., and then measure the mass of the collected dust particles with an electronic balance, etc. The speed of descent is obtained. When the particle number measurement is an object, the number of particles and the particle size on the adhesive tape are visually measured using a microscope. However, since this method requires much labor, it is mainly used for limited precision measurement in a short time.

  Public falling dust management is often performed using a deposit gauge shown in FIG. The falling dust deposited on the particle collection port 1 is passively collected together with rain water in the collection bottle 7 through re-scattering and a rain process. The total amount of dust collected during one month is converted into the average dust fall rate of the dust fall. Since this method is an officially accepted measurement method, it is required to show a correlation with the measurement value of this instrument in long-term measurement even when using any other falling dust measurement method. .

  Here, the ideal collection speed of falling dust is defined. In the case of falling dust, mainly deposition on the ground surface corresponds to actual environmental pollution. On the ground surface, the amount of dust deposited per unit area per unit time, that is, the dust drop rate, is the atmospheric dust concentration by dust type and particle size and the atmospheric particles by dust type and particle size directly above the ground surface. Defined by multiplying by settling velocity. Atmospheric particle sedimentation rates include those due to free fall of particles and those due to diffusion due to atmospheric turbulence. This dust drop speed is ideally satisfied even at the particle collection port entrance of the deposit gauge, and this is defined as the ideal collection speed. In an actual deposit gauge, the dust fall speed that can be collected is generally lower than the ideal collection speed due to the aerodynamic resistance of the instrument. The ratio of the actual dust fall rate to the ideal collection rate is called particle collection efficiency.

  The deposit gauge has a problem that it cannot be applied to a method for searching for a problem location by combining atmospheric dust amount measurement values in a short time because the time resolution of measurement is low. In addition, particles having a specific gravity of 1 and less than about 4 to 7 μm cannot easily adhere to the wall surface because of their high followability to the surrounding airflow. For this reason, particles of less than 4 μm are hardly collected in the deposit gauge.

  Rather than directly measuring the falling dust, a method of measuring the concentration of particles in the atmosphere and converting it to a dust falling speed is often used. A typical publicly recognized device for measuring particles in the atmosphere is the high volume sampler shown in FIG. Atmosphere containing dust from the particle sampling port 1 is sucked at a high flow rate by a blower or a compressor 6 and collected on a collection filter 5, and the mass of particles collected in a certain period of time is divided by the amount of suction air. The medium particle concentration is calculated. This measurement method has a certain rationality for particles having a relatively small diameter of, for example, 4 to 7 μm or less, but has a large error and is not practical for coarser particles. This is because coarse particles have a low ability to follow the surrounding atmospheric flow and are difficult to collect in the instrument even if they are sucked. Since the high volume sampler cannot automatically replace the filter, there is a problem that it is difficult to measure the continuous dust concentration transition.

  There is a suspended particulate matter (SPM) meter as a measuring device that measures a continuous concentration distribution transition using the same measurement principle of dust concentration in the atmosphere by suction. SPM is particles having a diameter of 10 μm or less in the atmosphere. An outline of the SPM meter having the configuration disclosed in Patent Document 1 will be described with reference to FIG. The atmosphere containing dust particles is sucked into the apparatus from the particle sampling port 1 by a blower or a compressor 6. Although there are no particular restrictions on the shape of the intake port of the SPM meter, in order to prevent rainwater inundation at the time of rain, it is usually the open end of a circular tube having an opening in the horizontal direction or in the lower part. In the air containing the sucked dust, coarse particles exceeding 10 μm are removed by the coarse particle filter 3 arranged immediately after the particle collection port. For the coarse particle filter, an aerodynamic classifier such as a greased impactor or cyclone is used. Coarse particles removed by the coarse particle filter are discarded outside the apparatus. The atmosphere containing only the SPM that has passed through the coarse particle filter flows into the β-ray absorption mass measuring instrument 4 through the particle sampling port air flow path 2 ′, and only dust in the air is collected on the collection filter 5. Is done. A β-ray absorption mass measurement is performed on the collected dust for a certain period of time. β-ray absorption mass measurement has the advantage of being able to measure the mass of a small amount of sample at a high speed in a dry and non-destructive manner, and is the most widely adopted method for continuous dust measurement in a short period of about 1 hour or less. After the mass measurement is completed, the collection filter feeding device 14 is operated to collect the dust collection filter from the β-ray absorption mass measuring instrument, and an unused collection for the next measurement. The filter part is fed into the β-ray absorption mass measuring instrument. In FIG. 3, a tape-shaped filter is used as the collecting filter, and a tape-shaped collecting filter that has been previously wound in a roll shape is sent out as a collecting filter feeding device to collect the collected tape. A mechanism that winds the collection filter into a roll is used. The intake air from which most of the dust has been removed by the collection filter 4 is directly discharged into the outside air through the air flow path 2 'during the β-ray absorption measurement. In addition, when collecting particles with a collection filter, it is inevitable in principle that extremely small particles pass through the collection filter. The upper limit diameter of the permeating particles is publicly determined to be a standard value, for example, 0.3 μm. Here, since the mass composition ratio of the extremely small particles in the atmosphere is generally small, the influence of the particles is ignored. Hereinafter, when simply described as “fine particles”, particles having a diameter of 0.3 μm or less (or particles that have been publicly recognized as collection filter transmission particles) are implicitly excluded. Since partial clogging on the collection filter occurs during suction of the air, the pressure resistance of the piping system changes every moment, so that the suction flow rate is controlled by the flow rate control device 9 etc. to compensate for this effect. It is controlled to be constant. Since the SPM meter is also a dust collection method by suction, it cannot be used for the purpose of collecting coarse particles.

  An advanced version of the SPM meter is the PM2.5 (particulate matter 2.5) meter. In the apparatus shown in FIG. 4 disclosed in Patent Document 2, the sucked air first passes through the coarse particle filter 3 to remove coarse particles having a diameter exceeding 10 μm in the atmosphere. Become only. Next, the air passes through the classifier 8, and among the SPMs, PM2.5 having a smaller diameter (particles having a median particle size distribution of 2.5 μm when converted to particles corresponding to a specific gravity of 1) and the others Air currents containing relatively coarse SPM particles are separated and dust particles are collected in separate collection filters. A virtual impactor which is a kind of inertia classifier is used for the classifier. The collected dust particles of the two systems are subjected to continuous mass measurement in each system by a β-ray absorption mass measurement method. The PM2.5 meter cannot be used for the purpose of collecting coarse particles. When an aerodynamic classifier such as a virtual impactor is used, it is inevitable in principle that some fine particles having high followability to the airflow are mixed into the airflow on the coarse particle side. However, since the amount of fine particles mixed is proportional to the flow rate ratio between the diverting flow paths in the virtual impactor and the flow rate divided to the coarse particles is generally small, the total amount of fine particles flowing to the coarse particles along with the diverted air flow is small. The ratio to the amount of suction fine particles is also small. For this reason, the influence of the fine particles diverted to the coarse particle side is generally ignored.

  As a device for directly and continuously measuring falling dust including coarse particles, a continuous falling dust meter has been devised. An outline of a commercially available apparatus is shown in FIG. As a basic structure, a deposit gauge type particle sampling port 1 having an opening upward is provided at the suction end of the SPM meter. Furthermore, in order not to perform substantial external air suction, the air sucked from the lower end of the particle sampling port circulates in the apparatus through the main circulation air flow path 11 ′ and is removed by the dust filter 10. It is a mechanism that is discharged into the particle sampling port. Although it is usually possible to measure the dust fall rate in units of one hour, it is impossible to measure with a shorter cycle than this because of the generally excessively small particle mass that can be collected. Therefore, the time resolution of this device is not sufficient. Also, in this device, the amount of dust fall is calculated by dividing the amount of dust collected per unit time by the cross-sectional area of the particle sampling port. In many cases, there is a problem that the cause is unknown, and the cause is unknown.

  In any of these measuring devices, it is necessary to collect the collected particles in the atmosphere on a filter. For this reason, the operation | work which replaces | exchanges the filter which collected the particle | grains for a new thing is required at any time, and the continuity of a measurement is prevented at every filter replacement | exchange. On the other hand, Patent Document 3 discloses an apparatus for continuously measuring a collected particle without trapping the particle in a filter or the like by immediately measuring the particle property in a non-destructive manner while the particle is floating. There are a light scattering type particle counter (particle counter) shown in FIG.

  The principle of the light scattering particle counter is shown in FIG. Particles in the atmosphere are sucked together with the atmosphere into the ventilation pipe 2 ′ in the measurement device, and light such as a laser is constantly irradiated by the light irradiator 50 and passes through the measurement unit. When the particles pass through the light, the light is scattered and the scattered light is detected by the light receiver 51. Since one scattered light detection pulse by the light receiver corresponds to one particle that has passed through the measurement unit, the number of particles that have passed through the measurement unit in a certain time can be calculated. Further, since the scattered light becomes stronger as the particle becomes larger, it is possible to obtain rough information on the size of the passed particle by simultaneously measuring the scattered light intensity. However, in order to measure all particles that have passed through the measurement unit, the light needs to cover the entire cross section of the air channel. As a result, when the concentration of particles in the atmosphere is high, there is a problem of multiple scattering in which light is irradiated to a plurality of particles at the same time, and the light detector detects the scattered light from a plurality of scattering sources and the accuracy decreases. Exists.

  The principle of the light transmission type particle densitometer is shown in FIG. Particles in the atmosphere are sucked together with the atmosphere into the ventilation pipe 2 ′ in the measurement device, and light such as a laser is constantly irradiated by the light irradiator 50 and passes through the measurement unit. When the particles pass through the light, the light is scattered and absorbed by the particles, and the amount of light reaching the light receiver 51 provided on the opposite surface is reduced. The particle concentration in the atmosphere is calculated from the light quantity reduction rate. In this calculation, a calibration curve for the relationship between the particle concentration and the light amount reduction rate is determined in advance for each particle type. The light transmission particle densitometer does not detect the scattering of individual particles, so the adverse effect on the measurement due to multiple scattering is small, and it can be applied to the atmosphere with high particle concentration (number of particles per unit volume). it can.

  Conventionally, there has been no application of a light scattering particle counter or a light transmission particle densitometer for continuous measurement of falling dust. This is because these measuring devices themselves do not have the ability to distinguish falling dust (coarse particles that can fall freely) from other fine particles. In principle, a light scattering particle counter may be able to identify only coarse particles corresponding to falling dust. However, mass measurement with a light scattering particle counter is effective only when the density and optical properties of the particles to be collected are known in advance. For objects that cannot be known, the particle size measurement error is large, so that only the dust falling can not be measured with a light scattering particle counter alone. In addition, when the concentration of the attracted particles is high, there is a problem that the detection accuracy of the falling dust is lowered due to the multiple scattering effect due to the large number of fine particles. Further, in principle, coarse particles are low in detection sensitivity per mass in the light transmission type particle concentration meter, and therefore it is difficult to measure the falling dust with the light transmission type particle concentration meter.

JP 2006-3090 A Japanese Patent No. 3574045 JP 2002-82038 A JP-A-1-307614

  As described above, in the prior art, it has a good correlation with the measured value of the dust fall rate by the deposit gauge, can measure the dust fall rate in a short period of about 1 to 10 minutes, and does not require a particle sampling filter. There is no continuous falling dust meter. For this reason, it is difficult to search for a problem location by a combination of a specific weather condition and a corresponding measurement value of atmospheric dust amount in a short time.

  An object of this invention is to provide the practical continuous-type dust measuring device applicable to this problem location search.

  Thus, as a result of the inventor's research on falling dust measurement, the following solution has been invented.

[First invention]
The first invention has a funnel-shaped particle sampling port having an opening directed upward and having a lower end connected to the air flow path,
A blower or a compressor for sucking atmospheric particles present in the particle sampling port together with the atmosphere from the lower end of the particle sampling port through the air flow path;
A classifier provided at a stage subsequent to the particle sampling port, and classifying the atmospheric particles sucked from the particle sampling port into coarse particles and fine particles;
A particle counter that is provided at the subsequent stage of the coarse particle side outlet of the classifier and continuously measures the number of particles in the atmosphere or both the number and size of the particles that pass through per unit time;
An air flow path for connecting the particle sampling port, the classifier, and the particle counter in this order, and exhausting the sucked air to the outside through the sucked air in order.
An air flow path for introducing an atmosphere having the same flow rate as the air flow sucked from the lower end of the particle collection port into the particle collection port, and a discharge compressor or a blower for introducing the air into the air flow path;
Is a continuous type falling dust measuring device.

  There is no conventional continuous falling dust meter that classifies particles sucked together with the air in advance and performs mass measurement for each classification size.

  In the theory of calculating the dust fall speed of the falling dust in the conventional beta ray absorption type continuous falling dust meter, all the mass of particles sucked per unit time from the lower end of the particle sampling port is divided by the sectional area of the inlet of the particle sampling port. The thing was the dust falling speed of the falling dust. However, as a result of detailed investigations by the present inventors, this theory has been found to be incorrect. This will be specifically described below.

  FIG. 7 shows a general flow field concept in a section near the particle sampling port of a continuous dust meter when there is a wind outdoors. The particle collection port can be roughly divided into two upper and lower regions. The upper part is an area controlled by the swirling flow generated by the entanglement of the wind of the outside air into the particle sampling port, and this is called the “outside air flow controlled area”. Unless a special wind reduction mechanism is installed at the particle sampling port inlet, the main flow velocity in the outside air flow control region reaches a value similar to the outside air velocity, for example, several m / s. The lower part is a region where the flow toward the lower end of the particle collection port is remarkable due to the intake air at the lower end of the particle collection port, and this is called an “intake dominant region”. The boundary between these two regions is referred to as “particle collection port internal flow field boundary” 18. The vertical position of the particle sampling port internal flow field boundary changes depending on the ratio of the outside air flow rate and the intake flow rate, and tends to move downward when the wind speed is high, and upward when suctioning at a high flow rate. The concept of the trajectory of particles entering the particle sampling port from the particle sampling port inlet on such a flow field in the particle sampling port is large and can be classified into the following three cases. The first case is a trajectory when the particle diameter is very large, for example, several hundred μm or more. The particle trajectory at this time is not affected by the flow field such as a swirling flow and is collected as it is. It flows into the measuring instrument together with the intake air from the lower end of the mouth (track a in FIG. 8). That is, since all the particles that have entered the particle sampling port inlet are sucked, the particle sampling port inlet acts as a substantial adsorption surface (referred to as a virtual adsorption surface). FIG. 8 shows the position of the virtual adsorption surface 22 of very coarse particles. The second case is a case of coarse particles having a general particle size that freely fall in the atmosphere having a particle size of several μm to several tens of μm. Particles entering the particle sampling port from the particle sampling port inlet Most of the air rotates along with the swirl flow in the external airflow control region, and some particles cross the internal flow field boundary of the particle sampling port and enter the intake control region. At the same time, it flows into the measuring instrument (trajectory c in FIG. 8), but most of the particles are discharged again from the particle sampling port inlet to the outside air (trajectory b in FIG. 8). In this case, the virtual adsorption surface 23 for the coarse particles having a general particle size coincides with the flow field boundary inside the particle sampling port. As evidence that the particle collection amount is not the particle sampling port inlet cross-sectional area but the virtual adsorption surface cross-sectional area, the present inventor has different particle sampling at the same circulation (suction) flow rate with respect to the conventional continuous dust meter Apparatuses with mouth inlet cross-sectional area conditions (diameters 130 mm, 200 mm, and 300 mm) were separately prepared, and dust collection experiments were simultaneously performed at the same point. As a result, almost the same amount of dust was obtained for all devices. As a result of measuring the velocity distribution inside the particle sampling port during particle sampling, the distance between the particle sampling port lower end and the particle sampling port internal flow field boundary (virtual adsorption surface) was constant in any apparatus. That is, it was found that the virtual suction surface area dominates the amount of dust collected. This fact was also found by the present inventors for the first time. The third case is the case of particles floating in the atmosphere of several μm or less, and the particle trajectory almost completely matches the flow of the atmosphere, so the particle concentration in the particle sampling port is almost uniform. Yes, the amount of particles sucked into the measuring instrument depends only on the intake flow rate and the outside air concentration (strictly speaking, the particle concentration decreases by the amount of the circulating flow discharged into the particle sampling port. Since the mass exchange with the inside of the particle sampling port is extremely strong, the particle concentration reduction effect due to the circulation flow can be substantially ignored). Therefore, there is no concept of a virtual suction surface. The particle trajectory is the same as in the second case. The relationship between the above classification and the conventional theory for calculating the dust fall speed in a continuous fall dust meter is described. In the case of the first very coarse particle, since all the particles that have passed through the particle collection port inlet are collected, there is no problem in the conventional theory. Next, in the case of the coarse particles having the second general particle size, only the particles that have passed through the particle collection port internal flow field boundary, that is, the virtual adsorption surface, are collected. The thing divided by should correspond to the dust falling speed of the falling dust. Therefore, the conventional theory that divides the collected amount by the particle inlet inlet cross-sectional area is incorrect. Further, in the case of the third fine particles, since the fine particles generally have a low deposition rate on the ground surface, the influence of the falling dust on the dust falling speed is essentially small. However, with the conventional device, regardless of whether the particles can actually deposit on the ground surface, the fine particles in the atmosphere are forcibly collected by suction, and the relationship between the collected particles and the dust falling speed of the falling dust is Since it is unknown, the basis of the calculated dust fall speed for the minute particles is weak. Therefore, the validity of the conventional theory that the total collected particles including the first to third particles are simply divided by the particle sampling port cross-sectional area and converted into the falling dust velocity is extremely low.

  The biggest problem on the hardware side of the conventional apparatus constructed based on the erroneous theory is that the particle size composition ratio of the collected particles cannot be measured. For this reason, even if the particle collection theory is appropriately corrected, it is not possible to correct the particle mass collected by the conventional apparatus for each collected particle size based on the correction theory and convert it to an appropriate dust fall measurement value. Is possible. Moreover, since the conventional apparatus shows the selectivity of the collected dust which is completely different from the deposit gauge, it is natural that the dust falling speed of the falling dust by the conventional apparatus is generally different from the deposit gauge.

  In the present invention, by collecting the particles corresponding to the falling dust separately from the other particles based on the above-mentioned new knowledge by the present inventor that cannot be known by those skilled in the art, This makes it possible for the first time to accurately measure the continuous dust drop speed. There is also an apparatus that performs continuous mass measurement independently by classifying SPM in the sucked outside air, such as the PM2.5 meter. However, with the PM2.5 meter, it is considered that the measurement accuracy cannot be satisfied even if a part of particles having a diameter of 10 μm or more that are difficult to collect by suction in the first place enters the particle collection port. Are excluded. For this reason, no consideration is given to the collectability of coarse particles. Further, the value of 2.5 μm in diameter related to the boundary of classification is set mainly from the viewpoint of the type of the source and the health effect, and is irrelevant to the concept of classification only of falling dust. In other words, the PM2.5 meter does not take any considerations regarding the collection of falling dust (the ratio of particles having a diameter of 10 μm or more is high) and mass measurement, and the PM2.5 meter is simply modified to make the present invention. It is difficult.

  In addition, in the conventional β-ray absorption continuous falling dust meter, most of the atmospheric particles sucked from the particle sampling port are captured by the collection filter, so the air that has passed through the mass meter is relatively clean. Met. For this reason, the amount of particles to be adsorbed by the dust removal filter provided in the subsequent stage of the mass measuring instrument was small in the first place, so that even if the dust removal filter had a small capacity, it could be operated without replacing the dust removal filter for a long time. However, since the collected particles are not collected for measurement in the present invention, the atmosphere that has passed through the particle counter contains high-concentration coarse particles. For this reason, when exhausting the air that has passed through the particle counter by configuring the circulation air flow path into the particle sampling port again, it is essential for measurement accuracy that the dust be removed from the air before exhausting to the particle sampling port. It is. If a filter is used to perform such dust removal, all the high-concentration coarse particles in the circulating air channel must be collected here. Therefore, a large-capacity filter is used, or the filter replacement frequency is conventionally changed. Must be increased more than. Therefore, in the present invention, the atmosphere containing a large concentration of coarse particles sucked from the particle sampling port is discharged into the atmosphere as it is after passing through the particle counter without constituting a circulation air flow path. On the other hand, for the atmosphere that must be discharged into the particle sampling port, an air intake pipe of another system is provided, and the atmosphere is supplied by directly sucking outside air through this. When the outside air is directly sucked by another airflow tube, coarse particles in the atmosphere are not concentrated unless a special particle sampling port shape such as a wax shape in the present invention is used. For this reason, since the particle concentration in the directly sucked outside air corresponds to the measurement object itself, it is not always necessary to remove the dust from the sucked air. Thus, the present invention is excellent in that the present invention does not require a large-capacity dust filter that is unavoidable with a simple combination of conventional devices.

  Furthermore, in the conventional beta ray absorption type continuous falling dust meter, the mass of the particles collected on the collection filter is measured together with the collection filter mass. For this reason, from the viewpoint of ensuring the SN ratio of measurement, the filter mass per β-ray transmission area is designed to be a value approximately equal to the mass of particles collected at this site. As a result, in the conventional apparatus, as the amount of particles collected on the collection filter increases during mass measurement, the air flow resistance increases in the air flow path system and cannot be ignored. It is essential for the conventional apparatus to provide a flow rate control device for maintaining. On the other hand, in the present invention in which particles in the suction atmosphere are not collected, the airflow resistance of the air channel system hardly changes during the measurement. Therefore, if the airflow resistance of the air flow path is designed in advance so that a predetermined air flow rate is obtained, the present invention does not require a flow control device. Thus, the present invention is excellent in that the flow rate control device is not necessarily required.

[Second invention]
In the second invention, the particle sampling port, the classifier, the particle counter, and the dust filter are connected in this order, and an air flow path that exhausts the sucked air to the outside and sequentially exhausts it to the outside. Instead of being connected to the air flow path for introducing the atmosphere into the particle sampling port,
The continuous falling dust measuring apparatus according to the first aspect, wherein a blower or a compressor for sucking air particles present in the particle sampling port also serves as the discharge compressor or the blower. is there.

  In the second invention, as in the first invention, the atmosphere is sucked from the lower end of the funnel-shaped particle sampling port, the particles in the sucked air are classified into coarse particles and smile particles, and then the coarse particles pass per unit time. The number and particle size distribution are measured by a particle counter, and the air having the same flow rate as the air flow sucked from the lower end of the particle sampling port is exhausted into the particle sampling port. The first difference from the first invention of the second invention configuration is that, in the second invention, the airflow pipe of the system that sucks air from the lower end of the particle sampling port and the airflow pipe of the system that exhausts air to the inside of the particle sampling port. It is a point which connects directly and comprises a circulation air flow path in a measuring device. As a result, the compressor or blower need only be provided for one system (for example, one). The second difference is that in the second invention, a dust filter is always provided in the air flow path. There has been no apparatus having such a configuration.

  As described in the description of the first invention, when measurement is performed using a particle counter, an air flow tube system is used when a circulation air channel is provided to exhaust the air sucked from the particle sampling port to the particle sampling port again. A large-capacity dust filter must be installed inside. However, when it can be predicted in advance that the average value of the dust fall speed is relatively small (for example, the device of the present invention at a point where the average dust fall speed is previously evaluated to be low by a deposit gauge which is a simple long period measurement method). If the measurement is performed over a short period for a long period of time, the capacity of the dust filter is relatively small for the apparatus of the present invention. Therefore, a circulation air flow path can be provided. In this case, since the compressor or blower that performs suction from the particle collection port can be shared with the compressor or blower that supplies air to the particle collection port, there is an advantage that the equipment can be simplified.

  Further, in the particle counter, on the basis of measurement principle, it is necessary to grasp the particle property of the particle whose actual size is measured, and create a calibration curve that associates the scattered light detection intensity with the particle size based on this information. In the present invention, the particles collected by the dust removal filter are analyzed off-line, and the average value of the particle properties (optical characteristics and specific gravity), which is essential information when performing mass measurement with a particle counter, is replaced with a dust removal filter. Can be determined for each.

  Furthermore, in the conventional beta ray absorption type continuous falling dust meter, the variation in ventilation resistance in the airflow tube system during measurement is unavoidable on the measurement principle, and it is essential to provide a flow control device in the airflow tube system. . On the other hand, in the present invention, there is no particular restriction on the capacity of the dust removal filter (that is, the portion that can only affect the air flow resistance fluctuation of the airflow pipe system in the present invention), so the particles collected for a certain period of time. By providing a dust filter having a sufficiently large capacity with respect to the total amount, fluctuations in ventilation resistance in the airflow pipe system during the measurement period can be suppressed to a level that can be ignored. By doing so, the flow control device is not necessarily required in the present invention, which is advantageous over the prior art.

[Third invention]
3rd invention provides the concentration measuring device which measures the density | concentration of the particle | grains in air | atmosphere in the back | latter stage of the fine particle side outflow port of the said classifier, The continuous type falling dust measurement as described in 1st or 2nd invention characterized by the above-mentioned Device.

  From the fine particle side outlet of the classifier, particles having an intermediate size between SPM and PM2.5 flow out. Particles of this size are said to have a significant adverse health effect, so there is great value in measuring the particle concentration in the atmosphere. In the present invention, the concentration of fine particles in the atmosphere can be measured simultaneously with the falling speed of the falling dust.

[Fourth Invention]
According to a fourth aspect of the present invention, a plurality of airflow resistors that generate airflow resistance in the direction perpendicular to the inlet surface of the particle sampling port are provided at the inlet of the particle sampling port at intervals in the direction perpendicular to the inlet surface of the particle sampling port. It is a continuous type falling dust measuring device according to any one of the first to third aspects of the invention.

  There is no conventional continuous dust meter in which a plurality of ventilation resistors are arranged at intervals in the particle sampling port.

  As described above, the flow field inside the particle sampling port of the continuous dust meter when there is a wind is greatly affected by outside air entrainment. For this reason, there exists a problem that particle | grain collection characteristics fluctuate | vary by the virtual adsorption | suction surface height raising / lowering with external air flow velocity. If the entrainment of outside air into the particle sampling port can be weakened or the outside air flow control area can always be limited to a certain position, the virtual suction surface height will be stabilized and the fluctuation of the particle collection characteristics will be reduced. Can do. Therefore, in the present invention, by installing a plurality of airflow resistors that generate airflow resistance in the direction perpendicular to the particle sampling port inlet surface, at intervals in the direction perpendicular to the particle sampling port inlet surface, Stabilization of the virtual suction surface height is achieved by reducing the wind speed of the outside air and substantially limiting the outside air flow control area to the area between the outermost and innermost airflow resistors. . In addition, by increasing the particle collection efficiency by raising the virtual suction surface, a larger amount of falling dust can be collected for the same suction flow rate, which is essential for measuring the amount of falling dust with high time resolution. An effect of improving a certain SN ratio can be exhibited.

  A conventional continuous dust meter may also be provided with an insect screen at the inlet of the particle collection port, which can function as a ventilation resistor. However, as a result of the inventor's investigation, if there is only one such ventilation resistor, a slight wind reduction effect is recognized, but it hardly affects the rise or stabilization of the virtual suction surface. It has been found. This is due to the following reason. First, in order to raise the virtual suction surface, it is necessary that the average suction flow velocity at the virtual suction surface is at least approximately the same as the outside air entrainment flow velocity here. Here, since the suction flow velocity is inversely proportional to the local cross-sectional area of the particle sampling port (that is, the square of the virtual suction surface height in the case of a conical funnel-shaped particle sampling port), the rate of decrease in the entrainment speed on the virtual suction surface is at most 1 / The virtual suction surface rises only by the square. Actually, when the virtual suction surface rises, the virtual suction surface gets closer to the outside air, and the flow velocity of the outside air entrainment flow at the virtual suction surface increases to inhibit the virtual suction surface from rising. It becomes a value considerably lower than the 1/2 power of the entrainment speed reduction rate. On the other hand, it is difficult to reduce the entrainment speed of the outside air flow rate by 50% or more even if a ventilation resistor having an opening ratio of a general insect screen is installed at the inlet of the particle sampling port. Therefore, the ascending margin of the virtual suction surface is also much less than 25%.

  The feature of the present invention shown in FIG. 12 is that a plurality of ventilation resistors 27, which cannot have a large wind reduction effect by themselves, are arranged in the vertical direction of the inlet of the particle sampling port, so that the entrainment flow of the outside air penetrates into the particle sampling port deep part. By preventing this, the virtual suction surface is stably maintained at a high level directly below the innermost ventilation resistor.

  The principle of the present invention will be described below. The entrainment of the outside air into the particle sampling port enters the particle sampling port deep direction along the inner surface downstream of the external air flow of the particle sampling port, and the main flow that rises along the upstream inner surface of the particle sampling port turns and turns. Form. The swirl flow is driven by the negative pressure distribution inside the particle sampling port generated by the entrainment effect of the external air flow. Within the particle sampling port, the upstream side of the external airflow has a lower pressure distribution, and the flow (swirl flow) of the external airflow from the leeward side to the leeward side is maintained in the particle sampling port. Due to the presence of the swirling flow, the negative pressure generated in the particle sampling port due to the entrainment effect is relieved.

  The effect on the swirling flow when a ventilation resistor is installed at the particle sampling port will be described. First, when a ventilation resistor having a large ventilation resistance is disposed alone at the particle sampling port inlet, the effect of increasing the virtual adsorption surface by reducing the flow velocity of the swirling flow is relatively small. This is because the negative pressure relaxation effect generated by the entrainment effect due to the external airflow is reduced by the decrease in the swirling flow velocity in the particle sampling port, and a stronger pressure gradient is generated in the direction of the external airflow in the particle sampling port. This is because the action of recovering is produced. Also, the effect of raising the virtual adsorption surface is relatively small even when a ventilation resistor having a large ventilation resistance is disposed alone at a portion sufficiently deeper than the particle sampling port inlet. In this case, the wind of the outside air at the inlet of the particle sampling port passes through the ventilation resistor by forming a thin thin high-speed air flow along the inner surface of the particle sampling port on the lower side of the external airflow without being reduced. For this reason, even if a slight wind reduction is performed by the ventilation resistor, the downward high-speed air flow that maintains the high speed still enters the deep part of the particle sampling port along the inner surface of the external air flow leeward particle sampling port. By the way, if a ventilation resistor having an extremely small aperture ratio (for example, an aperture ratio of 10%) is used, the virtual suction surface can be raised. However, with such a ventilation resistor, it is difficult to pass the dust that should be collected.

  Based on the above knowledge, the present inventor has conducted a detailed study, and if the generation of a thin high-speed air flow along the inner surface of the external airflow leeward particle sampling port is suppressed, the virtual adsorption surface is maintained at a high level stability. I found that I can do it. Specifically, by arranging the ventilation resistor so that the flow along the inner surface of the external airflow leeward particle sampling port passes through the airflow resistor having a relatively small resistance multiple times, the inner surface of the external airflow leeward particle collection port It is possible to suppress the generation of a thin high-speed air stream along This is due to the following reason. Even in the case of a ventilation resistor having a relatively small resistance, when the flow along the air flow downward inner surface of the particle sampling port passes through this, the downward velocity decreases and the mainstream near the particle sampling port inner surface The direction is slightly shifted from the downward direction to the upwind direction of the external airflow. This is because the main driving source of the flow field in the particle sampling port is a pressure gradient from the leeward direction of the external airflow immediately below the inlet of the particle sampling port to the upwind direction. This is because if the flow rate is slightly reduced, the downward flow rate that is excessive due to the deceleration is easily transferred in the driving force direction. However, a single ventilation resistor such as a conventional device has a small effect of reducing the wind flow and moving in the direction of the driving force along the inner surface of the airflow leeward direction of the particle sampling port in one passage of the airflow resistance. Since the rolling effect is small in the installation of), repeat this several times. As a result, at the point of passing through the innermost ventilation resistor, the flow along the inner surface of the particle sampling port along the leeward direction of the external airflow is sufficiently decelerated, so it is no longer possible to reach the deep part of the particle sampling port. The virtual suction surface is maintained immediately below the innermost ventilation resistance. The advantage of this method is that the swirl flow is inherently responsible mainly by appropriately guiding only the wind direction of the swirl flow rather than reducing the entire swirl flow that inevitably occurs in the particle sampling port when there is a wind. In other words, the high-level stabilization of the virtual adsorption surface is efficiently realized without impairing the relaxation effect of the pressure gradient in the particle sampling port due to the entrainment effect. In the conventional apparatus, knowledge about the flow field in the particle collection port is lacking, and not only the swirl flow in the particle collection port is controlled but also the existence of the swirl flow and its importance are not known at all. These new findings are indispensable for making the present invention.

[Fifth Invention]
According to a fifth aspect of the present invention, in any one of the first to fourth aspects of the present invention, a horizontal flow guide plate protruding outward in the radial direction of the particle sampling port is provided on an outer periphery in the vicinity of the inlet of the particle sampling port. It is a continuous type falling dust measuring device of description.

  In the conventional continuous dust meter, the particle sampling port has a simple truncated cone shape or a cylindrical shape, and no special additional processing is performed. The present invention differs from the prior art in that a flow guide plate is installed around the inlet of the particle collection port.

  The particle collection efficiency in the particle collection port of the continuous dust meter is determined by the virtual suction surface area as described above. The particle collection efficiency in the particle collection port represents the ratio of particles sucked from the lower end of the particle collection port among the particles that have passed through the particle collection port inlet and entered the particle collection port. On the other hand, as another factor that affects the overall particle collection efficiency, the particle inflow efficiency, which is the ratio of the particles passing through the particle collection port inlet to the ideal collection explained when the deposit gauge was explained, is Exists. The total particle collection efficiency is the particle inflow efficiency multiplied by the particle collection efficiency in the particle collection port. As described in the description of the deposit gauge, when the particle sampling port like a conventional continuous dust meter is a simple truncated cone or cylinder, the particle sampling efficiency is improved when there is wind due to the aerodynamic resistance of the particle sampling port. It shows a tendency to decrease significantly. As a result of the inventor's investigation, it has been found that this is caused by a decrease in particle inflow efficiency when there is a wind. If importance is attached only to the correspondence between the deposit gauge and the collected sample of the continuous dust meter, the same particle inflow efficiency reduction characteristics between both measuring instruments even if such a decrease in particle inflow efficiency exists. There is no problem if it is set to indicate. However, the original purpose of the measurement of the falling dust is to accurately evaluate the speed at which the falling dust is deposited on the ground surface of the measurement point. From this point of view, the instrument should be configured so that the particle collection efficiency is as close as possible to the ideal collection by increasing the particle inflow efficiency.

  Therefore, in the present invention, the flow guide plate 36 is installed around the inlet of the particle sampling port to improve the particle inflow efficiency. The principle is as follows. The cause of the decrease in particle inflow efficiency is that the external airflow rises at the front edge of the particle sampling port (upward side of the external airflow) due to the aerodynamic resistance of the particle sampling port and the measuring instrument body. Since the particles are lifted and pass directly above the particle sampling port, the particles cannot flow into the particle sampling port. In the present invention, the rise of the external airflow at the front edge of the particle sampling port is suppressed by the flow guide plate, and the external airflow is guided in the vicinity of the particle sampling port so as to flow parallel to the particle sampling port. Particle inflow efficiency can be increased. Furthermore, by increasing the particle inflow efficiency and improving the overall particle collection efficiency, a larger amount of falling dust can be collected for the same circulation (suction) flow rate, so the amount of falling dust with high time resolution The SN ratio improvement effect essential for measurement can be exhibited.

  In the particle collection theory of the conventional continuous dust meter, the total particle collection efficiency is implicitly regarded as 1, and the idea of improving the particle collection efficiency did not exist in the first place. Moreover, in the SPM meter, it has been known that the particle collection efficiency by suction is reduced by coarse particles. However, in the first place, since the SPM meter does not remove coarse particles in advance and does not measure it, there has been no idea to improve the particle inflow efficiency with respect to falling dust. In other words, any conventional technique lacks the idea of improving the particle collection efficiency at the particle collection port for coarse particles.

[Sixth Invention]
6th invention is equipped with the 1 type, or 2 or more types of combination among a vibrator, a brush, or an airflow spraying device for removing the adhering particle | grains of the particle collection port inner surface in the said particle collection port, It is characterized by the above-mentioned. It is a continuous type falling dust measuring apparatus as described in any one of the 1st-5th invention to do.

  In the conventional continuous dust meter, there is no special mechanism for removing particle deposits in the particle sampling port.

  The reason why there is no special mechanism for removing the particle deposits in the particle sampling port in the conventional continuous dust meter is as follows. First, in the conventional apparatus, there is no ventilation resistor in the particle sampling port, or even if it exists, the effect of reducing the wind is small. Sometimes it is always present when there is wind (high wind speed). The high-speed swirling flow rescatters the deposited particles on the inner surface of the particle sampling port, so that the inner surface of the particle sampling port is kept relatively clean. Second, since the diameter of the particle sampling port of the conventional apparatus put into practical use is limited to a small one of about 100 mm, the swirling flow can maintain a high speed up to a relatively deep part of the particle sampling port, at least, The problem that the effect of cleaning the inner surface of the particle sampling port by the swirling flow in the deep part of the particle sampling port is not significant when there is a wind. When there is no wind (at low wind speed), dust adheres to the conventional device, but if there is a wind condition after that, the particles inside the particle collection port collect the particles that had adhered before and dry and re-scatter. To do. For this reason, particles do not continue to adhere to the inner surface of the particle collection port for several days, and it is rare to find particle adhesion unless carefully observed. Therefore, the conventional apparatus has no idea of removing the adhered particles on the inner surface of the particle collection port. However, even in the prior art, for example, the amount of dust falling in a short period of about 1 hour has been a problem with the magnitude of the measured value, so that dust adheres to the inner surface of the particle sampling port when there is no wind speed. Results in delayed collection. Therefore, this adhesion should be avoided originally. That is, in the prior art, the necessity of preventing the adhesion of particles to the inner surface of the particle collection port has simply been not recognized.

  On the other hand, in the first to fifth inventions on which the present invention is based, from the viewpoint of measuring the amount of falling dust with high time resolution, the particle sampling port is expanded and the wind at the deep part of the particle sampling port is reduced. As a result, the problem of adhesion of particles to the inner surface of the particle collection port, which did not exist in the conventional apparatus, becomes obvious. The reason for this is as follows. First, when the particle sampling port is enlarged, the air flow velocity at the deep part of the particle sampling port is likely to decrease in the first place, and the effect of cleaning the inner surface of the particle sampling port is likely to decrease. Next, if the wind is reduced in the particle sampling port, the effect of cleaning the inner surface of the particle sampling port by the high-speed swirling flow is lost. If such particle adhesion to the inner surface of the particle collection port occurs, adverse effects such as a decrease in particle collection efficiency and a deterioration in the followability of the measurement value to the falling dust velocity fluctuation in the outside air occur. Therefore, in the present invention, this adverse effect is suppressed by installing a mechanism for preventing the falling dust from adhering to the inner surface of the particle sampling port.

Even in the conventional apparatus, when the circulating flow is discharged into the particle sampling port, it is discharged along the inner surface of the particle sampling port, and this discharge flow may cause a secondary effect of cleaning the inner surface of the particle sampling port. is there. Therefore, as a result of investigation by the present inventor, the average flow velocity of the discharge flow is higher than the swirling flow velocity in the particle sampling port in the conventional device when there is wind in the circulation flow rate (for example, 1 Nm ³ / hour) discharged by a commercially available conventional device. It turned out to be one digit smaller. For this reason, immediately after discharge, the discharge flow is turbulently mixed with the swirl flow, and there is almost no trace of the discharge flow remaining on the inner surface of the particle sampling port. That is, the particle collection port inner surface cleaning effect by the discharge flow is so small that it can be ignored, and the particle sampling port inner surface cleaning effect by the always existing swirling flow is outstanding. Therefore, the discharge flow of the circulating flow to the inner surface of the particle sampling port in the conventional apparatus cannot be regarded as a mechanism for preventing the adhesion of the falling dust.

  Such a phenomenon that dust easily adheres to the inner surface of the particle collection port when improving the amount of collected dust and the collection efficiency is a new finding found by the present inventors. Since this knowledge is not known in the prior art, little consideration has been given to dust adhesion on the inner surface of the particle sampling port.

[Seventh Invention]
7th invention is a continuous falling dust measuring apparatus as described in any one of 1st-6th invention characterized by having a heater which heats the inner surface in the said particle | grain collection port.

  In the conventional continuous dust meter, there is no special mechanism for heating the inner surface of the particle sampling port.

  In particular, when a continuous dust meter is used in a coastal area, it is inevitable that sea salt particles enter the particle collection port. The sea salt particles are deliquescent at a relative humidity of 70% or more, and the adhesion to the inner surface of the particle collection port is remarkably increased. Although it is considered that the sea salt particles adhered even in the conventional continuous dust meter, the sea salt particles adhering to the inner surface of the particle sampling port when dehumidified at high humidity are particles of the conventional device when the humidity is not high. Since it was easily dried by the high-speed swirling flow existing in the sampling port and removed from the inner surface of the particle sampling port by the air current, it was not noted.

  However, as a result of the inventor's investigation, sea salt particles deliquescent at high humidity and adhering to the inner surface of the particle sampling port are highly adherent, so other non-sea salt particles that have entered the particle sampling port are also adsorbed. As a result, it was found that the dust collection efficiency was significantly reduced temporarily. As a result, when the sea salt particles adhere to the inner surface of the particle sampling port and are deliquescent in both the present device and the conventional device, some of the non-sea salt particles are once deliquescent on the inner surface of the particle sampling port. As a result, it has become clear that there are problems that cause delays in mass measurement and reduced particle collection efficiency. Therefore, in the present invention, even when the humidity is high, the inner surface of the particle sampling port is heated to maintain the relative humidity in the vicinity of the inner surface of the particle sampling port at 70% or less, so The salt particles are dried, and the adhesion is reduced, thereby suppressing the decrease in dust collection efficiency. In addition, the present inventor has found that in order to prevent sea salt deliquescence, it can be realized by keeping the inner surface temperature of the particle sampling port at a temperature higher by 10 ° C. or more than the outside air temperature.

  In the prior art, these new findings found by the present inventors (deliquesed sea salt particles reduce particle collection efficiency, and in order to prevent this, the temperature of the inner surface of the particle collection port may be controlled. ) Was not known, little consideration was given to the deliquescence of sea salt particles inside the particle collection port.

[Eighth Invention]
The eighth invention is provided between the opening of the particle sampling port and the classifier to which the air sucked from the lower end of the particle sampling port first reaches the lower end of the particle sampling port. A continuous falling dust measuring device according to any one of claims 1 to 6, further comprising a horizontal swirl suppressor capable of suppressing a horizontal swirl component of the atmosphere including the particles sucked in is there.

  If there is a strong horizontal swirling flow component (that is, an airflow component having the central axis of the air flow path 2 as the center of rotation) in the airflow sucked from the particle sampling port, the following problem exists, and this component is suppressed. Should. First, the horizontal swirl flow component has the effect of pushing solid particles in the intake flow radially outward as seen from the central axis of the intake pipe, making it easier for the particles to adhere to the wall surface before reaching the measurement section, and reducing the particle collection rate. This is because adverse effects such as time delay of particle collection are caused. Next, in the first to eighth inventions, the aspirated atmospheric particles are classified using a classifier such as a cyclone or a virtual impactor, so that the horizontal swirl component adversely affects the classification characteristics. In particular, in the first to eighth inventions, the funnel-shaped particle sampling port is used, so that an unavoidable minute horizontal swirling flow generated at the particle sampling port inlet is sucked downward while the rotation radius is reduced. Since the swirling speed of the horizontal swirling flow increases rapidly due to the motion preserving effect, the necessity of suppressing the horizontal swirling flow is particularly great.

  The present invention has a good correlation with the dust fall rate measurement value by the deposit gauge, enables the dust fall rate measurement in a short period of about 10 minutes, and allows the particle size distribution to be continuously measured. It is now possible to search for problem areas by combining the meteorological conditions and the corresponding measurement values of atmospheric dust in a short time.

  Exemplary embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, in this specification and drawing, about the component which has the substantially same function structure, duplication description is abbreviate | omitted by attaching | subjecting the same code | symbol.

[First invention]
Hereinafter, an embodiment of the first invention will be described.

(Device configuration)
Next, the apparatus configuration in the first invention will be described with reference to FIG.

  The falling dust enters the measuring device together with the air flow through the conical wax-shaped particle sampling port 1 opened upward with respect to the atmosphere. In the apparatus, a gas flow channel 2 and a classifier 8 are provided at the subsequent stage, and a flow channel comprising a coarse particle branched air flow channel 12 and a fine particle branched gas flow channel 13 is connected to the subsequent stage, and the particle coarse A particle counting measuring device for counting the number of passing particles is provided in the particle branching gas channel, and the coarse particle branching gas channel and the microparticle branching gas channel merge at the latter stage, and are arranged in the latter stage. The blower or the compressor 6 sucks air particles present in the particle collection port from the lower end of the particle collection port.

  In addition, as a separate channel, external air sucked by the discharge compressor or blower 46 is introduced into the vicinity of the inlet inside the particle sampling port 1 through the discharge air channel 45. Introducing outside air by discharging to the particle sampling port is performed along the inner surface of the particle sampling port in the direction of the lower end of the particle sampling port evenly just below the dust particle sampling port inlet, as in the conventional continuous dust measuring device. It is desirable to do so.

  At this time, the ventilation resistance and the compressor operating condition are set so that the air flow rate sucked from the particle sampling port and the air flow rate discharged into the particle sampling port become the same. By doing this, since the amount of air exchanged between the inside of the sampling port and the outside air at the particle sampling port inlet becomes 0 on average, the adverse effect of atmospheric suction on the entry of falling dust from the sampling port inlet is reduced. Can do. The outside air sucked in order to be discharged into the collection port is preferably dust-removed in advance by a filter. However, if the suction of coarse particles can be ignored by making the collection port small, etc., it may not be removed. . Next, the flow of particles will be described. Part of the particles that have entered the particle collection port due to free fall of particles or intake air from the lower end of the particle collection port enter the air flow path 2. The dust particles in the air flow path flow into the classifier 8 by the air flow. Dust is classified inside the classifier, and is divided into an air flow mainly containing coarse particles (that is, falling dust) that can fall freely in the atmosphere and an air flow containing only other fine particles, respectively, for coarse particles. It divides into the branch air flow path 12 and the branch air flow path 13 for microparticles, and flows out from a classifier. The coarse particle branch air flow channel 12 enters the particle counter 20, and the particle counter 20 records the number of particles passing in a certain time and the size (for example, particle size distribution) of the individual particles. Using the particle size distribution passed for a certain time and the particle average specific gravity assumed in advance, the particle mass passed for a certain time is converted. By dividing the particle mass measurement value by the sampling time and the virtual adsorption area estimated using the particle sampling mouth velocity distribution obtained by numerical fluid analysis or actual measurement, the dust falling speed of the falling dust can be calculated. Some particle counters simply measure only the number of particles that have passed. Such an apparatus is often a low-priced apparatus that omits only the particle size conversion calculation function of the scattered light intensity measurement value based on a general particle counter that also measures the particle size. There is essentially no difference between a particle counter that only measures the number of particles and a general particle counter that also measures the size of the particles. When a particle counter that measures only the number of particles is applied to the present invention, instead of measuring the size of individual particles, the average particle size distribution and particle specific gravity previously measured on site are used. By always assuming that the average particle size distribution and the specific gravity of the particles are measured by the apparatus of the present invention, it can be converted into an average dust falling speed by the same method as that of a general particle counter. In the present invention, since the opening of the particle sampling port faces upward, it is necessary to prevent the rainwater from entering the measuring device during rainy weather and adversely affecting the instrument. For this purpose, the continuous dust meter is provided with a rain gauge 48, a particle collection mouth cover 49, and a particle collection mouth drive mechanism 47. When rain is detected by the rain gauge, the particle collection mouth drive device is provided. If the particle sampling port is moved to cover the particle sampling port and no rain is detected, the particle sampling port may be moved to open the particle sampling port to the outside air. The outside temperature is measured by the outside temperature gauge 30 so that the rain gauge can detect rain quickly, and the rain gauge feels so that the rain sensing surface of the rain gauge maintains the same temperature as the outside temperature. Rain surface temperature is controlled. Note that the setting / control of all the devices related to the device of the first invention and the recording / storing of measured values are carried out automatically by an arithmetic device (not shown) or by operating this arithmetic device from the outside. The Incidentally, an apparatus for calculating the dust fall rate from the measured value of the collected coarse particles such as the scattered light amount, and an apparatus for calculating the atmospheric particle concentration from the measured values of the collected transmitted light amount or scattered light amount of the fine particles, It does not necessarily have to exist in the measuring device. If this computing device is outside the measuring device, move the measured value such as the amount of light measured inside the measuring device to an external computing device, and calculate the dust fall rate and atmospheric particle concentration with the external computing device. That's fine. The advantage of this method is that it is not necessary to have a computing device for each measuring device, so that the size of the device is reduced. The data movement method may use a communication line, or may be performed by installing a recording device such as a removable hard disk in the measuring device and physically transporting the recording device.

  As another embodiment of the present invention, the apparatus configuration shown in FIG. 11 can be adopted. The difference from FIG. 6 is that a compressor or blower 6 is arranged in front of the classifier 8. By doing so, the classified fine particle side branched air flow path 13 can be exhausted to the outside as it is.

(Particle collection port)
The amount of dust falling is proportional to the virtual suction surface area, and the virtual suction surface area cannot be larger than the cross-sectional area of the particle sampling port inlet. Therefore, the dust particle sampling amount is increased to improve the SN ratio of particle mass measurement. From the viewpoint, it is advantageous that the area of the particle sampling port is large. It is desirable that the diameter of a US dust jar, which is at least a public long-term dust collector and essentially the same principle as the deposit gauge, be 110 mm or more, and more desirably, Based on the premise of falling dust collection, the particle collection port diameter in the deposit gauge can be 300 mm (British standard) or more. In addition, when the falling particle collection port is extremely large, it is difficult to avoid the adverse effect of dust adhesion to the particle collection port, so the particle collection port diameter can be made 1000 mm or less. However, as described above, the dust collection amount cannot be increased simply by enlarging the particle collection port inlet area, and should be applied in combination with the increase in the virtual suction surface due to the increase in the circulation (suction) flow rate. is there.

  The wax shape of the particle sampling port is preferably a truncated cone shape that expands upward (for simplicity, it is simply referred to as a conical shape), but it may be a polygonal pyramid with priority given to ease of processing. For rectification, only the part directly under the particle collection port inlet may be cylindrical, and the lower part may be conical.

  By the way, it is not so much a problem that the collected dust adheres to the vicinity of the particle sampling port in the case of a deposit gauge. This is because the deposit gauge is generally premised on measurement for a long time of about one month, and a washing and collecting effect due to rain during measurement can be expected. For this reason, although the particle collection port in the deposit gauge has a funnel-like shape, the apex angle when the funnel is regarded as a cone is an obtuse angle. However, in the first invention premised on short-time measurement of about one hour period, dust adhesion near the particle sampling port is not preferable because it causes a measurement time delay. For this reason, in the first invention, as means for suppressing dust adhesion in the vicinity of the particle collecting port, the particle collecting port is shaped like a wax, and the apex angle when this wax is regarded as a cone is an acute angle, more preferably 30 It can be below. Further, in the case of an extremely sharp angle, the length of the wax is so long that the area inside the particle collection port is greatly expanded to promote particle adhesion, so that the apex angle is preferably 5 ° or more. Regarding the material of the inner surface of the particle sampling port, in order to reduce the adhesion of dust, made of stainless steel, plated steel such as chrome plating and galvanization, aluminum, aluminum alloy, magnesium alloy, titanium alloy, or Surface fluororesin coating can be employed.

(Classification boundary)
A classification boundary in the classifier 8 of FIG. 6 will be described. Particles that can fall freely in the atmosphere have a diameter of 4 μm to 7 μm or more in terms of particles having a specific gravity of 1. Therefore, it is desirable to set a classification boundary in this range in order to selectively collect falling dust. The remaining classified fine particles are particles having a size definition intermediate between SPM and PM2.5, which is said to have a great health effect. Therefore, these classified fine particles are expected to have a close relationship with these health effects indicators and can be an important indicator for air quality assessment. There is great significance in doing. In addition, with emphasis on the compatibility with existing devices such as SPM meters and PM2.5 meters, coarse particles have a diameter of 10 μm or more, or more than the upper limit diameter of PM2.5 (although there is no legal standard, In principle, it is also possible to set the classification boundary so that the diameter is 3 μm. However, in this case, the collected coarse particles do not coincide with the falling dust diameter range (4 μm to 7 μm or more), so the measurement accuracy must be sacrificed considerably, and the application is limited.

(Classifier)
When directly measuring particles in the atmosphere with a light scattering particle counter, the sample needs to be sufficiently dry for accurate measurement. Further, in order to perform measurement in a short period, it is necessary to quickly send dust supplied one after another into the apparatus to the measuring unit. Furthermore, it is necessary to classify fine particles that hardly fall freely in the atmosphere. Furthermore, it is necessary to classify coarse particles of about several hundred μm contained in the dust. Electrostatic dust collection and wet classification are typical classification methods, but they are not suitable for such purposes. For classification of atmospheric dust, an inertia classifier or a centrifugal classifier that is dry and has a high processing speed regardless of the particle size should be used.

  As the inertia classifier, a louver classifier or an impactor classifier including a cascade type can be used. More desirably, a virtual impactor classifier having an advantage that the flow rate difference between the two branch flows after classification is relatively small and the flow rate can be easily controlled can be used as the application of the first invention. A cyclonic classifier can be used as the centrifugal classifier.

(Measuring instrument)
As the particle counter, a laser light scattering type particle counter is desirable from the viewpoint of accuracy and workability. Also, a γ-ray counter or an X-ray counter having the same principle can be used. Furthermore, a plate-like or columnar collision body may be provided in the air flow path, and an apparatus for detecting the number of particles by detecting the collision force of particles on the surface may be used. These can use a commercially available thing. In addition, a method using a photoacoustic method or an ultrasonic scattering method can be applied.

(Blower or compressor)
As these devices, those of the prior art can be used as they are.

(Flow path)
Since it is desirable to suppress the adhesion of dust, the inner surface is made of stainless steel, made of plated steel such as chrome plating or galvanization, aluminum, aluminum alloy, magnesium alloy, titanium alloy, or fluororesin coated tube Can be used.

(Flow control device)
A flow rate control device can be provided in the air flow path downstream of the particle counter. In the present invention, since there is no part that collects particles, the flow rate fluctuation during measurement is inherently relatively small, but it is more accurate by correcting the flow rate change due to temperature changes and compressor or blower performance over time. Can be measured. The flow rate control device is, for example, a flow rate measurement device such as a volumetric flow meter (or a flow rate measurement device or pressure measurement device capable of calculating a flow rate), a flow rate adjustment valve such as a butterfly valve and its actuator, and a control arithmetic device. Etc., which adjust the opening degree of the flow rate adjustment valve so that the air flow in the air flow path always has a predetermined flow rate can be used. Moreover, you may change the operating condition of a compressor or a blower as an actuator.

[Second invention]
Hereinafter, an embodiment of the second invention will be described with reference to FIG.

(Device configuration)
The difference from the apparatus of FIG. 6 is that the discharge compressor or blower 46 and the compressor or blower 6 are shared by connecting the exhaust of the compressor or blower 6 to the discharge air flow path 11. In this case, since the particles discharged into the sampling port are required to be clean, a dust filter 10 is provided after the particle counter.

(Dust removal filter)
Since the dust filter is not used for the measurement, a large capacity with a margin can be used, and if the dust filter is periodically replaced, the work is not stopped due to clogging or the like. As a filter material, a general glass fiber, a commercially available ceramic filter, or the like can be used. Further, the dust removal ability may be improved by coupling filters in series in multiple stages.

(Flow control device)
A flow rate control device can be provided in the air flow path downstream of the particle counter. In the present invention, by using a dust filter having a sufficiently large capacity, flow rate fluctuations during measurement can be suppressed without adjusting the flow rate, but by using a flow rate control device, slight flow rate fluctuations can be achieved. By correcting the above, it is possible to perform measurement with higher accuracy.

[Third invention]
Hereinafter, an embodiment of the third invention will be described.

(Device configuration)
This will be described with reference to the example shown in FIG. The difference from FIG. 15 is that a particle concentration measuring device is provided in the branched air channel 21 for fine particles. By doing so, it is possible to measure the continuous concentration change of only the fine particles in the atmosphere, which are said to have a great adverse effect on health.

(Concentration measuring device)
When the concentration of fine particles in the sucked air is low, a commercially available laser light scattering particle counter can be used. In this case, it is converted into the concentration of fine particles in the atmosphere using the measured value distribution of the fine particles that have passed through the measurement unit for a certain time, the ventilation air flow rate, and the predetermined average specific gravity.

  When the concentration of fine particles in the air is high, it is desirable to apply a light transmission type particle concentration measuring device. Specifically, a commercially available one using laser light or one using non-laser light can be used.

[Fourth Invention]
Hereinafter, an embodiment of the fourth invention will be described.

(Ventilation resistor)
The ventilation resistor must have an upper opening so as not to prevent the falling dust falling into the particle sampling port, and the structure where dust particles stay and adhere while passing through the ventilation resistor should be as small as possible. I must. Moreover, it is also necessary to have a shaft target structure so as not to cause fluctuations in particle collection characteristics due to the wind direction. Of course, a significant air flow resistance must be exhibited with respect to the passing air flow. From such a point of view, it is desirable to use a net having a relatively small opening. From the same viewpoint, a metal plate having a large number of minute holes or a fine honeycomb structure processed into a thin plate can also be used.

  As the material of the net or the like, a metal can be preferably used because it has a stable shape and hardly causes particle adsorption due to static electricity. More desirably, stainless steel made of a material that hardly changes its characteristics due to rust can be used. In addition, a net made of synthetic resin may be used in order to be cheaper.

  Desirably, the size of the opening of the ventilation resistor can be 0.3 mm or more and 2 mm or less. If the size is larger than this, airborne objects (insects, petals, dead leaves, etc.) other than dust may enter the particle collection port. Moreover, in the case of less than this, it becomes a problem that the coarse particle which occupies the ratio which cannot necessarily be disregarded in falling dust cannot be extract | collected. The opening ratio of the ventilation resistor most affects the ventilation resistance coefficient. Desirably, it can be in the range of 0.3 to 0.7. When the aperture ratio is higher than this, it does not function as an effective ventilation resistor. Also, an aperture ratio below this is not desirable because the collection rate of falling dust is extremely reduced.

(Arrangement of ventilation resistor)
From the viewpoint of preventing fluctuations in particle collection characteristics due to the wind direction, the main ventilation surface (mesh surface) of the ventilation resistor can be installed in a direction parallel to the particle collection port inlet. A plurality of ventilation resistors are installed in the vertical direction of the particle sampling port inlet, and the distance between the outermost and innermost ones is preferably at least 1/3 or more of the particle sampling port inlet diameter. As a result of the inventor's investigation, when installed at intervals of less than this, even if there are a plurality of ventilation resistors, only the same effect as the existence of a single resistor having a substantially large ventilation resistance is shown. Because there is no. As described above, such a ventilation resistor provided independently has a low virtual suction surface raising effect. This is because a certain distance is required for the high-speed airflow that has passed through the ventilation resistor to roll in the direction of the driving force, and if the ventilation resistor interval is too small, the high-speed airflow that has passed through the first ventilation resistor is This is because it passes through the next ventilation resistor before it is sufficiently moved in the driving force direction, and as a whole behaves as if it is a single ventilation resistor. There is no upper limit in principle for the distance between the outermost and innermost ones of the ventilation resistors. However, in the case of an extremely large interval, there is a problem that the apparatus becomes large and uneconomical, and the distance between the outside air and the lower end of the particle sampling port becomes large and the followability of measurement to the outside air particle concentration change is lowered. Therefore, the distance between the outermost and innermost parts of the ventilation resistor can be 3 times or less the particle sampling port diameter. The outermost side refers to the one closest to the particle sampling port inlet, and the innermost side refers to the one farthest from the particle sampling port inlet, that is, the one closest to the lower end of the particle sampling port.

  The higher the number of ventilation resistors, the higher the effect of stabilizing the virtual adsorption surface. However, if the airflow passes through an excessive number of ventilation resistances, the proportion of the dust in the airflow that adheres to the ventilation resistance also increases, leading to a decrease in the particle collection rate and should be avoided. Preferably, 2 to 5 ventilation resistors can be installed.

  In a region where a plurality of ventilation resistors are installed, a swirling flow exists and the particle concentration in the atmosphere is almost uniform. For this reason, this region does not have to be specially shaped like a conical wax. Therefore, the region between the outermost and innermost ventilation resistors can be cylindrical as shown in FIG. This cylindrical region exhibits the effect of rectifying the swirling flow and preventing it from entering the deep part of the particle sampling port, and thus can be regarded as the rectifier 35.

[Fifth Invention]
Hereinafter, an embodiment of the fifth invention will be described.

(Device configuration)
The apparatus configuration will be described with reference to FIG. A horizontal flow guide plate 27 having a width on the outer side in the radial direction of the particle sampling port is installed on the outer periphery in the vicinity of the particle sampling port inlet. The installation height can desirably be 5 to 20 mm below the particle collection port inlet height surface. This is because when the atmospheric wind passes over the flow guide plate, the boundary layer develops on the flow guide plate, so that the aerodynamic resistance of the particle sampling port itself is directly above the flow guide plate. Weak upward flow (as compared to the upward flow of the external air flow generated by the above-mentioned), a remarkable region of this upward flow, that is, the atmospheric flow excluding the range of 5 mm to 20 mm from the surface of the flow guide plate is This is because it is effective to improve the particle inflow efficiency. However, for the convenience of construction, even when the flow guide plate is installed at a higher position than this, a certain effect can be given to the particle inflow efficiency improvement.

(Flow guide plate)
The material of the flow guide plate may be any material as long as it has rigidity that functions as a structure and can withstand outdoor use. Metal, wood, synthetic resin, etc. can be used. The thickness of the flow guide plate is preferably thin from the viewpoint of reducing the aerodynamic resistance of the flow guide plate itself. Desirably, a thickness of about 0.1 mm to 5 mm can be used. When a thin flow guide plate is used, self-excited vibration of the flow guide plate may occur due to the external air flow, which may adversely affect the particle collection characteristics and device durability. Can support the flow guide plate. Furthermore, what was processed into the acute angle so that aerodynamic resistance may be reduced can be used for the outer peripheral part of a flow guide plate. The width of the flow guide plate (half the difference between the outer diameter and the inner diameter of the flow guide plate) can be desirably 50 mm or more. As a result of the inventor's investigation, if the width is less than this, the flow guide plate can suppress the upward air flow that can be generated near the front edge of the particle sampling port due to the aerodynamic resistance of the particle sampling port. In other words, the flow guide plate and the particle sampling port integrally act as aerodynamic resistance, and the external air current peels off at the front edge of the flow guide plate, resulting in a strong ascending air current. When the width of the flow guide plate is 50 mm or more, separation of the external air flow does not occur at the leading edge of the flow guide plate, and the effect of fixing the external air flow from the upstream to the horizontal plane can be exhibited regardless of the particle sampling port main body. At this time, the airflow excluded by the particle sampling port is guided not in the upward direction but in the horizontal plane direction. In this way, the flow field pattern in the vicinity of the particle sampling port changes at the width of 50 mm of the flow guide plate.

  The shape of the flow guide plate is preferably an axisymmetric shape with respect to the axis of the particle sampling port in order to suppress fluctuations in the particle inflow resistance due to the wind direction. Furthermore, it can desirably be a disk shape having a circular hole in the center. Although it is desirable that the surface of the current guide plate is essentially flat, a shape such as a corrugated plate can also be adopted to ensure strength. In addition to this, the shape of the flow guide plate is a truncated cone that extends upward, and a gap is provided between the lower part of the flow guide plate and the outer wall of the particle collection port, so that the dust falling on the flow guide plate is lowered. It is also possible to have a structure in which the liquid is dropped and discharged. However, as a result of the inventor's investigation, such a mechanism functions effectively only in the case of very coarse particles having a falling dust diameter of several hundred μm or more. Since particles easily adhere to the surface of the flow guide plate, the particle discharge effect is small. In addition, the frustoconical diversion plate has a relatively small effect of introducing the external airflow, and the effect of improving the particle inflow efficiency is limited.

  The falling dust deposited on the flow guide plate can re-scatter during strong winds. When the re-scattered particles flow into the particle collection port, the mass measurement accuracy of the collected particles is adversely affected. In order to prevent this, it is possible to suppress re-scattering of particles deposited on the flow guide plate by applying an adhesive substance such as grease to the surface of the flow guide plate.

[Sixth Invention]
Hereinafter, an embodiment of the sixth invention will be described.

(Device configuration)
Any adhesion particle removal mechanism is essential as long as it has the ability to prevent the adhesion of particles on the inner surface of the particle collection port or remove the adhered particles once and does not adversely affect the measurement. But it can be adopted. However, if the removed particles are discharged to the outside of the system, the particle collection efficiency decreases, so that the particles removed from the inner surface of the particle collection port are once again released into the air inside the collection port and the mass from the lower end of the collection port. It is desirable to be sucked to the measuring instrument side. In the adhered particle removing apparatus shown in FIG. 18, a vibration exciter 39 is provided on the outer surface of the particle collecting port, and this is periodically operated to remove particles adhering to the inner surface of the particle collecting port from the inner surface. A commercially available knocker or an eccentric motor type shaker can be used as the shaker. When a knocker is used, it can be vibrated at a frequency of 0.1 to 100 times / second.

  In the attached particle removing apparatus shown in FIG. 19, the brush attached on the inner surface of the particle removes the particles adhering to the inner surface of the particle sampling port from the inner surface. As a method of sliding the brush, for example, a brush driving device 41 that rotates on the central axis of the particle sampling port and moves up and down in the direction of the rotation axis can be used. A commercially available brush can be used. In consideration of workability, the size of the brush is desirably 0.01 to 0.5 times the maximum inner diameter of the particle sampling port in the radial direction of the particle sampling port. The length of the brush hair is preferably 1 to 300 mm in consideration of workability. The material of the brush is preferably made of a synthetic resin such as nylon or a metal such as stainless steel in consideration of strength and contamination resistance at the contact portion with the inner surface of the particle sampling port. A commercially available electric motor can be used for the rotation of the brush drive device, and a hydraulic cylinder or the like that performs hydraulic control can be used for the vertical movement of the brush drive device.

  In the example of the adhered particle removing apparatus using the airflow spraying device shown in FIG. 20, air is sprayed at high speed from the nozzle 43 moving on the inner surface of the particle sampling port to adhere to the inner surface of the particle sampling port. Remove particles from the inner surface. The air to be blown can be obtained from the airflow pipe 42 branched from the circulation air flow path 11. In addition, when the air flow to be blown is sufficiently small compared with the circulation flow in the measuring device, air is blown from outside air using a compressor (not shown) without branching the blowing air flow pipe from the circulation air flow. Direct suction may be used. As a method for moving the nozzle, for example, a nozzle driving device 44 that rotates on the central axis of the particle sampling port and simultaneously moves up and down in the direction of the rotation axis can be used. A commercially available electric motor can be used for the rotation of the nozzle driving device, and a hydraulic cylinder or the like that performs hydraulic control can be used for the vertical movement of the nozzle driving device. The flow rate of the airflow to be blown can desirably be 1 m / s or more in order to ensure the removability of particles from the inner surface of the particle sampling port, and has a great adverse effect on the flow field inside the particle sampling port. In order not to give, it can be 50 m / s or less. It is desirable that the nozzle converges and collides with the inner surface of the particle collection port as much as possible from the viewpoint of particle releasability, and a commercially available full cone nozzle or direct spray nozzle can be used. The inner diameter of the nozzle outlet may be appropriately determined in consideration of the spraying flow rate and the spraying flow velocity, and may be set to 0.1 to 50 mm, for example. The material of the nozzle can be a metal such as stainless steel in consideration of durability and contamination resistance.

  These adhering particle removing devices can be used alone, but the effect can be further enhanced by combining a plurality of these adhering particle removing devices. For example, the vibrator is highly resistant to contamination because it does not directly contact the particle sampling port. On the other hand, the airflow spraying device can adversely affect the airflow inside the particle sampling port, but has a higher particle removal capability. Furthermore, the brush can reduce the collection efficiency by attaching particles to the hair of the brush, but has the highest particle removal ability. Therefore, when these devices are used in combination, the vibration generator is used most frequently, the air blowing device is operated less frequently for particles that cannot be separated by the vibration device, and the frequency is lower. By operating the brush, it is possible to remove particles and avoid adverse effects on work.

[Seventh Invention]
Hereinafter, an embodiment of the seventh invention will be described.

(Device configuration)
The apparatus configuration will be described with reference to FIG. A heater 28 such as an electric resistance heater is attached to the entire back surface of the dust particle sampling port inner surface, and the particle sampling port inner surface is heated by this heater. The temperature of the inner surface of the particle sampling port is measured by a particle sampling port inner surface thermometer 29 such as a thermocouple attached to the inner surface of the particle sampling port, and the outside air temperature is measured by the outer temperature thermometer 30 of the same mechanism. The temperature control device 31 controls the heating amount of the heater using a PID control method or the like so that the measured particle sampling port inner surface temperature is higher by 10 ° C. or more than the outside air temperature measurement value. As another heating method, an infrared heater may be installed on the inner surface or outer surface of the particle sampling port, and the heating output may be controlled to radiately heat the particle sampling port to a predetermined temperature. Alternatively, the particle sampling port may be made of an electric conductor or a semiconductor, and the particle sampling port may be directly energized for heating. Furthermore, the particle sampling port may be heated by contacting a hot water tube or a hot air tube around the particle sampling port and controlling the temperature and flow rate of the working fluid. A burner may be provided on the outer surface of the particle collection port to heat the particle collection port directly. The upper limit of the inner surface temperature of the particle sampling port should be determined from an engineering point of view by comprehensively judging the thermal durability of the device and the cost for heating. Preferably, the average annual maximum temperature at the measurement point is + 15 ° C. Can be the upper limit temperature. Also, the heating amount control mechanism of the heater can be omitted in order to save equipment costs. In this case, the amount of heating at which the particle sampling port inner surface temperature is always higher than the outside air temperature + 10 ° C. is obtained in advance, and heating can always be performed with the amount of heating. In this case, the inner surface temperature of the particle sampling port must be set to a temperature much higher than the outside air temperature + 10 ° C. on average.

[Eighth Invention]
Hereinafter, an embodiment of the eighth invention will be described.

  The eighth aspect of the invention will be described with reference to FIG. 17 showing a device in which a horizontal swirl suppressor 38 is added to the device of FIG. The horizontal swirl flow suppressor should be installed below the inlet of the particle sampling port so as not to disturb the outside air flow, and above all the classifiers so as not to adversely affect the classification characteristics of particles in the atmosphere. Should be installed in.

  In addition, it is effective to suppress the horizontal swirl flow downstream after the lower end of the particle sampling port. The classifier may have any structure as long as the horizontal swirling flow component can be suppressed. However, the method of blocking the horizontal swirling flow by providing a wall surface in the vertical direction of the horizontal swirling flow is simple and obstructs the axial flow. It is desirable because it is difficult. For example, a structure in which a plurality of thin plates are combined as shown in FIG. 17 can be used (an example in which the horizontal swirl flow suppressor 38 is installed inside the particle sampling port). The dimension of the thin plate constituting the horizontal swirl flow suppressor can be set to a thickness of 0.1 to 5 mm and an axial length of 2 to 100 mm from the viewpoint of having sufficient wind resistance and not hindering the axial flow. As a material of the horizontal swirl suppressor, a metal such as stainless steel, ceramics, glass, or a synthetic resin such as a fluororesin can be used as a material to which particles in the air hardly adhere.

Example 1
The falling dust measuring device having the structure shown in FIG. 6 was operated outdoors to perform continuous measurement of falling dust. The particle collection port has a stainless steel structure of a conical wax shape with an inlet diameter of 200 mm, and the apex angle when the wax is regarded as a cone is 25 °. As a method of discharging the circulating air current to the particle sampling port, the entire surface was discharged directly and directly downward along the inner surface of the particle sampling port immediately below the particle sampling port inlet. The inner surface of the air channel was all made of stainless steel. A virtual impactor is used for the classifier, the blower operation is set so that the intake air flow rate becomes 1 Nm ³ / hour, and air flow including fine particles with a diameter of 6 μm or less and coarse particles other than that for particles having a specific gravity of 1 Classification was carried out to the air currents contained, and mass measurement was performed independently. The definition of classification here is that particles having a diameter of 6 μm are separated at a ratio of 90% in the branch airflow tube for coarse particles and 10% in the branch airflow tube for fine particles with respect to particles having a specific gravity of 1. Further, regarding the discharge air flow path, the shape of the inlet was a downward straight pipe to prevent rain, and the outside air was directly sucked without removing dust. The operation of the discharge blower was set so that the flow rate in the discharge air flow path was 1 Nm ³ / hour. All the air passages were made of stainless steel. As the blower, a commercially available general axial flow type was used.

  Particle mass measurement is performed by continuously measuring the frequency and size of particles passing through the measuring section using a commercially available laser light scattering particle counter, and analyzing the sample particles collected in advance with a deposit gauge on site. The obtained average specific gravity and optical characteristics were used to convert to a dust falling speed, and the value was stored as electronic data. Laser light having a wavelength of 780 nm and an output of 2 mW was used, and a photodiode element was used for the light receiver.

  In addition, the rain was detected using a commercially available rain gauge not shown, and when it rained, a lid not shown covered the particle sampling port entrance so that rain water did not enter the measuring instrument.

  Continuous automatic measurement for 6 months was performed using this apparatus.

  The monthly dust drop rate calculated by dividing the accumulated value of the mass of coarse particles collected by this device every month by the particle inlet entrance area was compared with the monthly dust fall rate by the deposit gauge at the same point. As a result, the average collected amount of this device is about 80% of the deposit gauge, and the standard deviation of the fluctuation of [Monthly dust fall rate by deposit gauge] / [Monthly dust fall rate by this device] is 0.15. there were. Therefore, it was possible to obtain a relatively strong correlation between the coarse particle measurement value and the deposit gauge measurement value obtained by this apparatus.

  Moreover, 6 hours of the falling dust rate every 10 minutes by this apparatus was compared with that measured by replacing a commercially available adhesive tape type falling dust collector every 10 minutes at the same point and at the same time. As a result, the standard deviation of the fluctuation of [Dust falling speed for 10 minutes with adhesive tape] / [Dust falling speed for 10 minutes with this device] is about 0.3, which is the first practical short time for continuous dust meter. Measurement at a period (average for 10 minutes) was realized.

(Comparative Example 1)
Using the conventional continuous dust meter shown in FIG. 5, the collected dust mass was measured by the same method at the same point and the same time as Example 1. As a result, the average collected amount was about 130% of the deposit gauge, and the standard deviation of the fluctuation of [Monthly dust fall speed by deposit gauge] / [Monthly dust fall speed by this apparatus] was 0.35. Therefore, although a correlation is recognized between the coarse particle measurement value and the deposit gauge measurement value by this apparatus, it is inferior to the present invention.

(Example 2)
A test was performed in the same manner as in Example 1 except that the falling dust measuring device having the structure shown in FIG. The blower operation was set so that the circulating air flow rate would be 1 Nm ³ / hour on average over time. As the dust removal filter, a ceramic filter for 0.3 μm was installed downstream of a general-purpose fibrous filter for 1 μm to purify exhaust. As a result, as for the measurement result of coarse particles, an average dust fall rate of 80% was obtained with respect to the monthly dust fall rate of the corresponding deposit gauge. Moreover, the standard deviation of [Monthly dust fall speed by deposit gauge] / [Monthly dust fall speed by this apparatus] was 0.15. In addition, 6 hours of the falling dust speed every 10 minutes by this apparatus was compared with the measurement of the corresponding adhesive tape type falling dust collector.

  As a result, the standard deviation of the fluctuation of [10 minutes dust falling speed by adhesive tape] / [10 minutes dust falling speed by this apparatus] was about 0.3.

(Example 3)
A test was performed in the same manner as in Example 2 except that the apparatus shown in FIG. A commercially available laser light transmission densitometer was applied as a concentration measuring device for atmospheric particles. A laser beam having a wavelength of 380 nm and an output of 1 mW was used. The correspondence between the amount of laser transmitted light and the local atmospheric particle mass concentration was investigated in advance, a calibration curve was created, the instantaneous atmospheric particle concentration was calculated based on this, and the average value for each month was obtained. The result was compared with the monthly PM2.5 concentration of PM2.5 meter installed at the same point.

  As a result, the average atmospheric concentration of this device is about 140% of that measured by PM2.5 meter, [Monthly atmospheric PM2.5 concentration by PM2.5 meter] / [Month atmospheric fine particle concentration by this device] The standard deviation of the fluctuation was 0.2. Therefore, it was possible to obtain a strong correlation between the microparticle measurement value and the PM2.5 measurement value obtained by the present apparatus.

Example 4
A test similar to that in Example 1 was performed using an apparatus set in the same manner as in Example 1 except that the cylindrical rectifier shown in FIG. 12 was installed at the particle sampling port. The rectifier had a diameter of 200 mm and a height of 80 mm, and a circular wire mesh as a total of three ventilation resistors was installed with an interval of 40 mm. The wire mesh is stainless steel, and has a mesh of 20 mesh and an aperture ratio of 50%, and is arranged so as to be in close contact with the inner wall surface of the rectifier. As a result of measuring coarse particles, an average dust fall rate of 85% was obtained with respect to the monthly dust fall rate of the corresponding deposit gauge. In addition, the standard deviation of [Monthly dust fall speed by deposit gauge] / [Monthly dust fall speed by this apparatus] was 0.12. In addition, 6 hours of the falling dust speed every 10 minutes by this apparatus was compared with the measurement of the corresponding adhesive tape type falling dust collector. As a result, the standard deviation of the fluctuation of [10-minute dust falling speed by adhesive tape] / [10-minute dust falling speed by this apparatus] was about 0.22, and the accuracy of short-time measurement of this apparatus was improved.

(Example 5)
The test was performed under the same conditions as in Example 4 except that the intervals between the ventilation resistors were set to 20 mm in the rectifier. As a result of measuring coarse particles, an average dust fall rate of 75% was obtained with respect to the monthly dust fall rate of the corresponding deposit gauge. Moreover, the standard deviation of [Monthly dust fall speed by deposit gauge] / [Monthly dust fall speed by this apparatus] was 0.15. In addition, 6 hours of the falling dust speed every 10 minutes by this apparatus was compared with the measurement of the corresponding adhesive tape type falling dust collector. As a result, the standard deviation of the fluctuation of [10 minutes dust falling speed by adhesive tape] / [10 minutes dust falling speed by this apparatus] was about 0.29, and a remarkable improvement was recognized as compared with Example 1. There wasn't.

(Example 6)
A test similar to that in Example 1 was performed using an apparatus set in the same manner as in Example 1 except that the disc-shaped flow guide plate shown in FIG. 13 was installed in the vicinity of the particle sampling port. A stainless steel disk having a thickness of 1 mm and a diameter of 320 mm was used as the flow guide plate, and the flow guide plate was mounted 10 mm below from the particle sampling port inlet. Grease was periodically applied on the flow guide plate to prevent re-scattering of deposited dust. As a result of measuring coarse particles, an average dust fall rate of 110% was obtained with respect to the monthly dust fall rate of the corresponding deposit gauge. In addition, the standard deviation of [Monthly dust fall speed by deposit gauge] / [Monthly dust fall speed by this apparatus] was 0.14. In addition, 6 hours of the falling dust speed every 10 minutes by this apparatus was compared with the measurement of the corresponding adhesive tape type falling dust collector. As a result, the standard deviation of the fluctuation of [10 minutes dust falling speed by adhesive tape] / [10 minutes dust falling speed by this apparatus] was about 0.27.

(Example 7)
The same test as in Example 6 was performed except that the diameter of the flow guide plate was 280 mm. As a result of measuring coarse particles, an average dust fall rate of 82% was obtained with respect to the monthly dust fall rate of the corresponding deposit gauge. In addition, the standard deviation of [Monthly dust fall speed by deposit gauge] / [Monthly dust fall speed by this apparatus] was 0.14. In addition, 6 hours of the falling dust speed every 10 minutes by this apparatus was compared with the measurement of the corresponding adhesive tape type falling dust collector. As a result, the standard deviation of the fluctuation of [10 minutes dust falling speed by adhesive tape] / [10 minutes dust falling speed by this apparatus] was about 0.3, and a marked improvement was recognized as compared with Example 1. There wasn't.

(Example 8)
A commercially available pneumatic knocker was installed outside the particle sampling port, and the same test as in Example 5 was performed using the same apparatus as in Example 4 except for this. Three knockers were installed in the circumferential direction, each having a different installation height. The supply pressure to the knocker was 1 kg / cm ^2, and each particle sampling port was struck at a frequency of once every 10 seconds. As a result of measuring coarse particles, an average dust fall rate of 95% was obtained with respect to the monthly dust fall rate of the corresponding deposit gauge. In addition, the standard deviation of [Monthly dust fall speed by deposit gauge] / [Monthly dust fall speed by this apparatus] was 0.11. In addition, 6 hours of the falling dust speed every 10 minutes by this apparatus was compared with the measurement of the corresponding adhesive tape type falling dust collector. As a result, the standard deviation of the fluctuation of [10 minutes dust falling speed by adhesive tape] / [10 minutes dust falling speed by this apparatus] was about 0.2.

Example 9
The particle sampling port heating mechanism shown in FIG. 14 was installed, and the same test as in Example 4 was performed using the same apparatus as in Example 8 except for this. In addition, the heating apparatus was not installed in the knocker installation location on the outer surface of the particle sampling port. A resistance ceramic heater was used as the heating device, and a thermocouple was used as the temperature measuring device, and the particle sampling port inner surface temperature and the outside air temperature were measured. Moreover, PID control was performed so that the particle sampling port inner surface temperature was set to the outside air temperature + 15 ° C., and the target temperature was maintained by the electronic arithmetic unit in the measuring instrument. As a result of measuring coarse particles, an average dust fall rate of 100% was obtained with respect to the monthly dust fall rate of the corresponding deposit gauge. In addition, the standard deviation of [Monthly dust fall speed by deposit gauge] / [Monthly dust fall speed by this apparatus] was 0.10. In addition, 6 hours of the falling dust speed every 10 minutes by this apparatus was compared with the measurement of the corresponding adhesive tape type falling dust collector. As a result, the standard deviation of the fluctuation of [10 minutes dust falling speed by adhesive tape] / [10 minutes dust falling speed by this apparatus] was about 0.2.

(Example 10)
The test similar to Example 1 was implemented using the apparatus similar to Example 1 except having the horizontal swirl flow suppressor 38 shown in FIG. The horizontal swirl flow suppressor was configured by combining stainless steel plates having a plate thickness of 0.3 mm and an axial length of 30 mm so that the end surfaces of the plates were cross-shaped when viewed from above, and were installed at the lower end of the particle sampling port. As a result of measuring coarse particles, an average dust fall rate of 86% was obtained with respect to the monthly dust fall rate of the corresponding deposit gauge. In addition, the standard deviation of [Monthly dust fall speed by deposit gauge] / [Monthly dust fall speed by this apparatus] was 0.12. In addition, 6 hours of the falling dust speed every 10 minutes by this apparatus was compared with the measurement of the corresponding adhesive tape type falling dust collector. As a result, the standard deviation of the fluctuation of [10-minute dust falling speed by adhesive tape] / [10-minute dust falling speed by this apparatus] was about 0.22, and the accuracy of short-time measurement of this apparatus was improved.

  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 this example. It will be apparent to those skilled in the art that various changes and modifications can be made within the scope of the claims, and these are naturally within the technical scope of the present invention. Understood.

It is a schematic diagram of a prior art. It is a schematic diagram of another prior art. It is a schematic diagram of another prior art. It is a schematic diagram of another prior art. It is a schematic diagram of another prior art. It is a schematic diagram of one embodiment of the first invention. It is a schematic diagram of the flow field in the particle collection port. It is a mimetic diagram of a particle locus in a particle collection mouth. It is a schematic diagram of a measurement principle. It is a schematic diagram of another measurement principle. It is a schematic diagram of other embodiment of 1st invention. It is a schematic diagram of one Embodiment of 4th invention. It is a schematic diagram of one Embodiment of 5th invention. It is a schematic diagram of one Embodiment of 7th invention. It is a schematic diagram of other embodiment of 2nd invention. It is a schematic diagram of one Embodiment of 3rd invention. It is a schematic diagram of one Embodiment of 8th invention. It is a schematic diagram of one Embodiment of 6th invention. It is a schematic diagram of other embodiment of the 6th invention. It is a schematic diagram of further another embodiment of the sixth invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Particle collection port 2 ... Air flow path 2 '... Air flow path 3 ... Coarse particle filter 4 ... Mass measuring instrument 5 ... Collection filter 6 ... Blower or compressor 7・ ・ ・ Collecting bottle 8 ・ ・ ・ Classifier 9 ・ ・ ・ Flow control device 10 ・ ・ ・ Dust filter 11 ・ ・ ・ Circulating air channel 11 ′ ・ Main circulating air channel 12 ・ ・ ・ Branch air channel for coarse particles 13 ... Branch air channel for fine particles 18 ... Boundary flow field boundary of particle collection port 20 ... Particle counter 21 ... Particle concentration measuring device 22 ... Virtual adsorption surface for ultra coarse particles 23 ··· Virtual adsorption surface of general coarse particles 27 ··· Ventilation resistor 28 ··· Heater 29 · · · Particle sampling port inner surface thermometer 30 · · · Outside temperature thermometer 31 · · · Temperature control device 32 · ..Diverter 35 ... Rectifier 36 ... Current guide plate 37 ... Bypass classifier 38 ... Horizontal swirl flow suppressor 39 ... Exciter 40 ... Brush 41 ... Brush drive device 42 ... Blowing airflow tube 43 ... Nozzle 44 ... Nozzle drive device 45 ... -Discharge air flow path 46 ... Discharge compressor or blower 47 ... Particle collection palate drive device 48 ... Rain gauge 49 ... Particle collection palate 50 ... Light irradiation machine 51 ... Light reception Container 52 ... Particle

Claims (8)

A funnel-shaped particle sampling port having an opening facing upward and having a lower end connected to the air flow path;
A blower or a compressor for sucking atmospheric particles present in the particle sampling port together with the atmosphere from the lower end of the particle sampling port through the air flow path;
A classifier provided at a stage subsequent to the particle sampling port, and classifying the atmospheric particles sucked from the particle sampling port into coarse particles and fine particles;
A particle counter that is provided at the subsequent stage of the coarse particle side outlet of the classifier and continuously measures the number of particles in the atmosphere or both the number and size of the particles that pass through per unit time;
An air flow path for connecting the particle sampling port, the classifier, and the particle counter in this order, and exhausting the sucked air to the outside through the sucked air in order.
An air flow path for introducing an atmosphere having the same flow rate as the air flow sucked from the lower end of the particle collection port into the particle collection port, and a discharge compressor or a blower for introducing the air into the air flow path;
A continuous type falling dust measuring device characterized by comprising: The particle sampling port, the classifier, the particle counter, and the dust filter are connected in this order, and the air flow path that exhausts the sucked air to the outside and sequentially exhausts it to the outside instead of discharging to the outside. Connected to the air flow path for introducing the atmosphere into the particle sampling port,
2. The continuous falling dust measuring device according to claim 1, wherein a blower or a compressor for sucking air particles present in the particle sampling port also serves as the discharge compressor or the blower.   The continuous type falling dust measuring device according to claim 1 or 2, wherein a concentration measuring device that measures the concentration of particles in the atmosphere is provided downstream of the fine particle side outlet of the classifier.   A plurality of air flow resistors that generate airflow resistance in the direction perpendicular to the inlet surface of the particle sampling port are installed at the inlet of the particle sampling port at intervals in the direction perpendicular to the inlet surface of the particle sampling port. The continuous falling dust measuring device according to any one of claims 1 to 3.   5. The continuous type according to claim 1, further comprising a horizontal flow guide plate projecting radially outward of the particle sampling port on an outer periphery in the vicinity of the inlet of the particle sampling port. Falling dust measuring device.   The said particle | grain collection port is equipped with 1 type, or a combination of 2 or more types among a vibration exciter, a brush, or an airflow spraying device for removing the adhering particles on the inner surface of the particle collection port. The continuous falling dust measuring device according to any one of? 5.   The continuous particle fall measurement device according to any one of claims 1 to 6, wherein the particle collection port has a heater for heating the inner surface of the particle collection port.   The particle sampling port is provided between an opening of the particle sampling port and the classifier to which the air sucked from the lower end of the particle sampling port first reaches, and is sucked toward the lower end of the particle sampling port The continuous falling dust measuring device according to any one of claims 1 to 6, further comprising a horizontal swirling flow suppressor capable of suppressing a horizontal swirling flow component of the atmosphere including particles.