JP4952261B2 - Concentration measuring device, concentration measuring system, and concentration measuring method - Google Patents

Description

  The present invention relates to a concentration measuring device, a concentration measuring system, and a concentration measuring method, and more particularly to a concentration measuring device, a concentration measuring system, and a concentration measuring method for measuring the concentration of dust floating in a gas.

  Asbestos (asbestos) has been recognized as a harmful substance that causes severe health problems (eg asbestos lung, lung cancer, mesothelioma) in the human body. Is prohibited, but there are some that are still incorporated in buildings as building materials.

  Therefore, in order to prevent the occurrence of health hazards caused by asbestos, such as workers who are deconstructing buildings, the Occupational Safety and Health Act is to prevent or suppress the emission of harmful asbestos dust (dust). Rules for prevention of asbestos disorders are stipulated. In addition, the Air Pollution Control Law stipulates that the concentration of asbestos that is fibrous (columnar) particles satisfies the reference value of 10 or less per liter of air.

  In addition, company to perform demolition work of building is to monitor whether there is asbestos-containing dust scattering from the inside (indoor) to the outside (outdoor) where the asbestos-containing building materials are removed The concentration in the atmosphere of the asbestos-containing dust collected from the atmosphere indoors and outdoors (hereinafter referred to as “asbestos concentration”) is measured at the timing described later with reference to FIG.

  As an asbestos concentration measurement method, there is a method in which particles captured when air is filtered are directly observed with a phase-contrast microscope (hereinafter referred to as “PCM method”).

  In the PCM method, first, air is sucked to collect (sample) dust containing asbestos particles contained in a predetermined volume of air. At this time, the size of the particles to be collected is set to several hundred μm or less by using a membrane filter. Next, the measurer uses an electron microscope to find the fibrous particles from the particles on the thin film filter, that is, the collected particles. Here, as the fibrous particles, those having a length of 5 μm or more, a diameter (width) of less than 3 μm, and an aspect ratio indicating a length to width ratio value of 3 or more are searched for by the measurer. Then, the measurer actually counts the fibrous particles found in this way as asbestos particles, thereby obtaining the number of asbestos particles per predetermined volume, that is, the asbestos concentration in the atmosphere.

FIG. 7 is a timing chart showing the timing of asbestos concentration measurement by the conventional PCM method.
As shown in FIG. 7, the conventional PCM method is executed three times before, during, and after work in all steps of dismantling work such as buildings. Further, it is also executed at the end of each work section during the dismantling work as necessary. The measurement result of the asbestos concentration by the PCM method executed a plurality of times in this way is recorded in the construction record of the dismantling work.

  Further, as an asbestos concentration measurement method different from the PCM method described above, “Determination of asbestos content measurement method (Determination of asbestos in building material products) defined in Japanese Industrial Standard standard number JIS A 1481 (March 25, 2006). in building material products) ”(hereinafter referred to as“ JIS method ”).

  This JIS method is a combination of “confirmation of dispersion color by disperse staining using a phase contrast microscope” (hereinafter referred to as “dispersion staining”) as qualitative analysis and X-ray diffraction analysis as quantitative analysis. Is. In the disperse dyeing method, asbestos particles are identified from the fibrous particles by observing changes in color depending on the shape of the sample and the refractive index of the sample. Thereby, the presence or absence of asbestos can be identified. In the X-ray diffraction analysis method, asbestos is quantified based on the X-ray diffraction intensity measured when the asbestos is irradiated with X-rays.

In addition, unlike the PCM method and the dispersion dyeing method, a suspended particle measuring apparatus that automatically detects fibrous particles such as asbestos from particles in a fluid has been proposed (for example, see Patent Document 1). This suspended particle measuring device first detects the vertical and horizontal components of the polarization of the scattered light obtained by orienting particles suspended in the fluid in the direction of the electric field and then irradiating the particles with laser light. Yes. As a result of this detection, when the vertical component of polarized light is greater than the horizontal component, that is, when positive polarized light is obtained, the particles in the fluid are identified as fibrous particles.
Japanese Patent No. 2881731 (paragraphs 0020, 0021 and FIGS. 7 and 8)

  However, although the PCM method and the suspended particle measuring apparatus described above can identify fibrous particles from particles to be measured with high accuracy, there is a possibility that the fibrous particles are organic matter or other mineral fibers. include. Similarly, in the above X-ray diffraction analysis method, the X-ray diffraction peak of asbestos overlaps with the X-ray diffraction peaks of antigolite and lizardite that are not asbestos, so antigolite and lizardite are included in the measurement target. In some cases, accurate quantification cannot be performed. Therefore, it cannot be said that the accuracy of asbestos concentration measurement is sufficiently high in any asbestos concentration measurement method.

  In addition, although disperse dyeing can accurately identify asbestos particles from the collected dust, it is necessary for the measurer to count the asbestos particles, resulting in individual differences in the measurement results and the reliability of the measurement results. poor.

  Similarly, even in the PCM method, since the measurer identifies the fibrous particles, the reliability of the measurement result is poor. In addition, the PCM method requires a long time of 1 to 7 days until the measurement result of the asbestos concentration is obtained, and thus cannot be said to be a simple measurement method. Furthermore, within the period until the measurement results are obtained, the emission of asbestos and other dust, as well as the exposure of asbestos to workers working in the dismantling of buildings, etc., and residents in the vicinity of the workplace ( Exposure) may occur, and it cannot be said that the safety of workers and residents is sufficiently secured. Therefore, it is required to measure the asbestos concentration quickly.

  Furthermore, since the X-ray diffraction analysis method requires detailed analysis using a large X-ray diffractometer (XRD), asbestos concentration measurement can be easily performed in the vicinity of the workplace. Can not. As a result, a great deal of time is required until the measurement result of the asbestos concentration is obtained. Therefore, as described above, it is required to measure the asbestos concentration quickly.

  The present invention has been made in view of the conventional problems as described above, and its purpose is to provide a concentration measuring apparatus and concentration capable of quickly measuring asbestos concentration while maintaining high detection accuracy of asbestos particles. It is to provide a measurement system and a concentration measurement method.

In order to achieve the above object, a concentration measuring apparatus according to claim 1 of the present invention is a concentration measuring apparatus for measuring the concentration of dust floating in a gas, and is filtered from the dust by filtering using a filter. A filtration unit for extracting particles having a size less than or equal to, an ashing unit for ashing organic matter, and a pair of electrodes for orienting the dust after passing through the filtration unit and the ashing unit in the direction of an electric field And a counting unit that counts the fibrous particles contained in the dust oriented by the pair of electrodes .
According to the concentration measuring apparatus of the present invention, the fibrous particles contained in the dust floating in the gas can be selectively counted.

The concentration measuring apparatus according to claim 2 is the concentration measuring apparatus according to claim 1, wherein the ashing section includes at least one of a plasma generating device and a heat generating device.
According to the concentration measuring apparatus of the present invention, the organic matter contained in the dust floating in the gas can be efficiently ashed.

The concentration measuring device according to claim 3 is the concentration measuring device according to claim 1 or 2, wherein the counting unit irradiates the dust after passing through the filtering unit and the ashing unit with a laser beam. A light irradiation unit, a scattered light intensity measuring unit for measuring the intensity of scattered light of laser light from the dust, and identifying the fibrous particles from particles contained in the dust based on the intensity of the scattered light And an identification unit.
According to the concentration measuring apparatus of the present invention, the fibrous particles contained in the dust floating in the gas can be optically counted.

In order to achieve the above object, a concentration measuring system according to claim 4 of the present invention is based on the concentration measuring device and the number of the fibrous particles connected to the concentration measuring device and counted by the counting unit. And an analysis device for analyzing the dust.
According to the concentration measurement system of the present invention, it is possible to selectively count the fibrous particles contained in the dust floating in the gas.

A concentration measurement system according to a fifth aspect is the concentration measurement system according to the fourth aspect, further comprising an operation unit for operating the concentration measurement device.
According to the concentration measuring system of the present invention, the concentration measuring device can be operated remotely.

The concentration measurement system according to claim 6 is the concentration measurement system according to claim 4 or 5, wherein the concentration of the fibrous particles in the gas is equal to or greater than a predetermined threshold as a result of the analysis of the dust by the analysis device. It is characterized by including a determination unit for determining whether or not.
According to the concentration measurement system of the present invention, the user can take safety measures when the concentration of the fibrous particles is equal to or higher than a predetermined threshold.

In order to achieve the above object, a concentration measuring method according to claim 7 of the present invention is a concentration measuring method for measuring the concentration of dust floating in a gas using a concentration measuring device, and filtering using a filter. A filtration step for extracting particles having a predetermined size or less from the dust, an ashing step for ashing organic matter, and the dust after passing through the filtration unit and the ashing unit are separated by a pair of electrodes. An alignment step for aligning in the direction of the electric field, and a counting step for counting the fibrous particles contained in the dust aligned by the pair of electrodes .
According to the concentration measuring method of the present invention, it is possible to selectively count the fibrous particles contained in the dust floating in the gas.

The concentration measuring method according to an eighth aspect is the concentration measuring method according to the seventh aspect, wherein at least one of a plasma generating device and a heat generating device is used in the ashing step.
According to the concentration measuring method of the present invention, organic substances contained in dust floating in a gas can be efficiently ashed.

The concentration measuring method according to claim 9 is the concentration measuring method according to claim 7 or 8, wherein the counting step irradiates the dust after the filtration step and the ashing step with laser light. An irradiation step, a scattered light intensity measuring step for measuring the intensity of the scattered light of the laser light from the dust, and an identification for identifying the fibrous particles from the particles contained in the dust based on the intensity of the scattered light And a step.
According to the concentration measuring method of the present invention, the fibrous particles contained in the dust floating in the gas can be optically counted.

The concentration measuring method according to claim 10 is the concentration measuring method according to any one of claims 7 to 9, wherein the dust is analyzed based on the number of the fibrous particles counted in the counting step. It has an analysis step.
According to the concentration measuring method of the present invention, it is possible to selectively count the fibrous particles contained in the dust floating in the gas.

The concentration measurement method according to claim 11 is the concentration measurement method according to any one of claims 7 to 10, further comprising an operation step of operating the concentration measurement device.
According to the concentration measuring method of the present invention, the concentration measuring device can be operated remotely.

The concentration measurement method according to claim 12 is the concentration measurement method according to claim 10 or 11, wherein the concentration of the fibrous particles in the gas is equal to or greater than a predetermined threshold as a result of the analysis of the dust in the analysis step. It has the discrimination | determination step which discriminate | determines whether it is.
According to the concentration measuring method of the present invention, the user can take a safety measure when the concentration of the fibrous particles is equal to or higher than a predetermined threshold.

  According to the present invention, since the organic matter is ashed, it is possible to maintain high detection accuracy of asbestos particles, and the concentration measuring device automatically counts fibrous particles, so that asbestos concentration measurement can be performed quickly. Can do.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a block diagram schematically showing a configuration of a concentration measuring system including a concentration measuring apparatus according to an embodiment of the present invention.

  The concentration measurement system 1 shown in FIG. 1 is used, for example, in a work place 40 where the asbestos-containing building material is removed in a sealed space (security zone) and its surrounding area. For example, five concentration measurement devices 10 and The analyzer 30 is connected to the concentration measuring apparatus 10 through a wired cable so as to be capable of serial communication. In the concentration measurement system 1, each concentration measurement device 10 measures the concentration of dust floating in the local atmosphere, and the analysis device 30 is included in the atmosphere based on the measurement data received from the concentration measurement device 10. Analyzes the dust that was stored. In addition, although the work place 40 is a sealed space, a worker or the like who performs the removal work can enter and exit from the entrance 41.

  As shown in FIG. 1, the concentration measuring apparatus 10 is installed in a building boundary and in the vicinity of a dust collector 42 in two workplaces 40, and is installed between the building boundary and the site boundary. Thus, one unit is installed in the vicinity of the site boundary, for example, the north side and the south side, and one unit is installed so as to be movable between the outside of the building boundary and the site boundary.

  The analysis device 30 is installed in a field office (not shown) provided between the building boundary and the site boundary, and is realized by an information processing device such as a personal computer (PC) 31 that can perform arithmetic processing. Is done. Connected to the PC 31 are a recording unit 32 for recording data, a display unit 33 for performing display based on the data, and an interface 34 for connecting to the five concentration measuring apparatuses 10. .

  The analysis device 30 is connected to PCs in the head office 50 and the branch 51 via a communication line such as the Internet, and can be connected to the portable terminal 52 via a wireless communication line. Furthermore, the analysis device 30 has an operation unit (not shown) operated by the user to control the power on / off of each concentration measuring device 10 and the moving direction of the concentration measuring device 10 that is movably installed. Prepare. Thereby, each concentration measuring apparatus 10 can be operated remotely.

  The mobile terminal 52 is preferably a mobile phone, for example, and is owned by a site supervisor who supervises the workplace 40.

  The number of concentration measuring devices 10 provided in the concentration measuring system 1 is five in FIG. 1, but any number may be used as long as one or more. Further, the concentration measuring device 10 may be installed inside the work place 40 (indoor). Further, although the concentration measuring device 10 is connected to the analyzing device 30 via a wired cable, it may be connected via a wireless communication line.

FIG. 2 is a block diagram showing the configuration of the concentration measuring apparatus 10 in FIG.
As shown in FIG. 2, the concentration measuring apparatus 10 includes a filtration unit 11, an ashing unit 13, and an air pump 15, and flow paths 12 and 14 are provided between the units. A count unit 20 is installed around the road 14. The air pump 15 performs constant-speed suction of gas at, for example, 2 liters per minute, so that the atmosphere containing dust collected through the filtration unit 11 is filtered into the filtration unit 11, the flow path 12, the ashing unit 13, And sequentially passes through the flow path 14.

  The filtration unit 11 is provided with a hollow intake port that is processed into a substantially tapered shape so as to suck the air outside the concentration measuring device 10. In addition, a flow path is also formed inside the filtration unit 11, and a thin film filter having a pore diameter of, for example, 0.8 μm and a diameter of 45 mm is inserted into the flow path perpendicularly to the flow path. The thin film filter filters atmospheric dust passing through the flow path. As a result, particles having a predetermined size, for example, a particle size of 700 μm or less, are extracted from the dust contained in the atmosphere as particles to be measured by the concentration measuring apparatus 10.

  A plasma generator is mounted inside the ashing unit 13, and the plasma generator generates plasma in a flow path formed inside the ashing unit 13. As a result, among the particles passing through the flow path, the organic matter is instantly ashed (inorganic) and becomes a fine particle having a particle size of 5 μm or less.

  As will be described later with reference to FIG. 3, the count unit 20 is configured to count the fibrous particles contained in the dust after passing through the filtration unit 11 and the ashing unit 13, and the concentration measuring device 10. Transmits the count value obtained by the count unit 20, that is, the number of fibrous particles, to the analysis device 30 as data.

  According to the configuration of FIG. 2, since each part of the concentration measuring device 10 is integrally configured, it is possible to perform a series of steps from dust collection to asbestos concentration measurement. As a result, it is possible not only to quickly measure the concentration of asbestos in the workplace 40 and in the vicinity of the workplace 40, but also to measure the asbestos concentration in real time throughout the day. Further, by constituting each part of the concentration measuring apparatus 10 with a small device, the transportation to the inside of the work place 40 or the vicinity of the work place 40 becomes easy. Further, since the user only needs to turn on the power of the air pump 15, the asbestos concentration can be easily measured.

  Although the ashing unit 13 is equipped with a plasma generating device, a heater as a heat generating device may be mounted instead of the plasma generating device, and both the plasma generating device and the heater are installed. It may be installed. That is, the ashing unit 13 may have any configuration as long as it can ash the organic matter.

  In FIG. 2, the arrangement of the filtration unit 11 and the ashing unit 13 may be interchanged. Furthermore, an air pump for the flow path 12 may be provided in the ashing unit 13. Thereby, time can be spent for the ashing of the organic matter by the ashing unit 13.

FIG. 3 is a block diagram showing in detail the configuration of the count unit 20 in FIG.
In FIG. 3, the count unit 20 includes a pair of optical windows 24 a and 24 b provided on the flow path 14 so as to face a laser 21 that emits laser light via the flow path 14, and an optical window 24 b. A photodiode 26 that receives the transmitted light, that is, transmitted light, and photomultipliers (photomultiplier tubes) 29a and 29b that receive scattered light derived from the optical window 24a are provided.

  The laser 21 is preferably a helium neon laser that emits a laser beam having a wavelength of 632.8 nm, but is not limited to a helium neon laser, and has a wavelength suitable for optically detecting asbestos particles. Any light source that can emit light may be used.

  Further, as shown in FIG. 3, between the laser 21 and the flow path 14, reflection mirrors 22 and 23 are provided between the laser 21 and the flow path 14 so as to guide the laser light emitted from the laser 21 into the flow path 14 through the optical window 24a. Has been placed. Therefore, the laser 21, the reflection mirrors 22 and 23, and the optical window 24a function as a light irradiation unit that irradiates the dust in the atmosphere that has already passed through the filtration unit 11 and the ashing unit 13 with laser light.

  Further, a reflection mirror 25 is disposed between the flow path 14 and the photodiode 26 in order to guide the laser light that has passed through the optical windows 24 a and 24 b, that is, transmitted light, to the photodiode 26.

  Between the optical window 24a and photomultipliers (photomultiplier tubes) 29a and 29b, an achromatic lens (chromatic aberration correction lens) 27 for polarizing scattered light derived from the optical window 24a and an achromatic lens 27 are provided. A beam splitter 28 including a prism 28a that disperses the polarized light obtained by passing the light into its vertical component and horizontal component is disposed. Note that as the scattered light, as shown in FIG. 3, it is preferable to use scattered light in the rear direction, for example, in the direction of 170 degrees with respect to the incident light incident on the optical window 24a. Thereby, fibrous particles having an aspect ratio of 3 or more can be easily detected.

  The photomultiplier 29a measures the light intensity of the polarized component of the received scattered light, and the photomultiplier 29b measures the light intensity of the polarized component of the received scattered light. The photomultipliers 29a and 29b are connected to the identification unit 29c, and input the measured polarized light intensity of the scattered light to the identification unit 29c.

  The identification unit 29c compares the light intensity of the polarized light with respect to the horizontal component and the vertical component. When the vertical component of the polarized light is larger than the horizontal component, that is, when positive polarized light is obtained, The particles are identified as fibrous particles such as asbestos, and the fibrous particles are optically counted.

  Next, an asbestos particle counting method executed in the counting unit 20 of the concentration measuring apparatus 10 will be described.

  First, in the flow channel 14, the atmosphere including dust that has already passed through the filtration unit 11 and the ashing unit 13 passes in the direction of arrow A in the figure, and particles such as dust in the flow channel 14 are The optical windows 24a and 24b are oriented in the direction of an electric field generated from a pair of electrodes (not shown) that sandwich the flow path 14 in the vicinity.

  Laser light from the laser 21 enters the flow path 14 through the optical window 24a. At this time, the transmitted light of the laser light is emitted from the optical window 24 b and enters the photodiode 26. On the other hand, laser light scattered by dust particles in the flow path 14, that is, scattered light, exits from the optical window 24 a and enters the photomultipliers 29 a and 29 b via the beam splitter 28. Here, the scattered light is obtained from particles having a predetermined particle diameter or larger, for example, 5 μm or larger, among the dust particles irradiated with the laser light. Therefore, the incinerated organic matter has a particle size of 5 μm or less, and is excluded from the measurement target of the concentration measuring device 10. Thereby, the possibility that the fibrous particles are asbestos particles can be increased, and thus the accuracy of the asbestos concentration measurement by the concentration measuring device 10 can be sufficiently ensured. Specifically, the concentration measuring apparatus 10 has higher detection accuracy of asbestos particles than a measurement member detects fibrous particles by a dispersion dyeing method or the like.

  The light intensity of the scattered light incident on the photomultipliers 29a and 29b is input to the identification unit 29c as measurement data, and the identification unit 29c determines the fiber from the particles contained in the dust based on the measurement data of the light intensity. Identify and count particles.

  Note that the fibrous particles to be counted may contain inorganic substances such as glass fibers and rock wool. By counting these as asbestos particles, the concentration measuring apparatus 10 is more safe. High measurement results can be obtained.

  FIG. 4 is a flowchart of the measurement result real-time display process executed in the analysis device 30 in FIG.

  In FIG. 4, first, in step S <b> 401, the analysis device 30 receives a count value indicating the number of fibrous particles from the concentration measurement device 10. Next, the analysis device 30 calculates the asbestos concentration in the atmosphere based on the amount of air sampled when the concentration measurement device 10 samples the atmosphere containing dust and the count value received from the concentration measurement device 10 (step). S402). Note that the amount of collected air can be calculated from the flow rate of the gas to be sampled determined by the suction force of the air pump 15 and the cross-sectional area of the suction port of the filtration unit 11. Therefore, it is preferable to previously register data such as the amount of air collected from each concentration measuring device 10 in the analysis device 30.

  In subsequent step S403, the analysis device 30 displays the calculated asbestos concentration on the display unit 33 in real time as the measurement result of the concentration measurement device 10.

  Further, the analysis device 30 determines whether or not the calculated asbestos concentration is equal to or greater than a predetermined threshold (step S404). As a result of the determination, if the asbestos concentration is not greater than or equal to the threshold value, data such as the calculated asbestos concentration is transmitted to the PC of the head office 50 or branch 51 (step S405). As this threshold value, it is preferable to set a numerical value corresponding to the asbestos concentration stipulated by law or a stricter reference value than that.

  Next, in step S406, it is determined whether or not to terminate the real-time display in step S403. If the result of the determination is that the real-time display is not terminated, the process returns to step S401 to continue the real-time display. When ending is completed, this processing is ended.

  As a result of the determination in step S404, if the calculated asbestos concentration is greater than or equal to a predetermined threshold, in addition to the real-time display in step S403, a predetermined warning display is performed (step S407), and data such as asbestos concentration and asbestos concentration are displayed. Is transmitted to the portable terminal 52 and the PCs of the head office 50 and the branch 51 (step S405), and the process proceeds to step S406. A warning sound may be emitted when the warning is displayed.

  According to the process of FIG. 4, the measurement result of the asbestos concentration by the concentration measurement device 10 is displayed in real time on the display unit 33 of the analysis device 30 (step S403), so the user constantly monitors the surrounding area including the work place 40. It can be performed.

  Further, according to the processing of FIG. 4, when the asbestos concentration is equal to or higher than the threshold value during real-time display, a warning is displayed (step S407). Safety measures can be taken efficiently by prioritizing confirmations, thereby improving the safety of workers and residents in the vicinity. In addition, since this warning is displayed at the time of real-time display, asbestos and other dust are emitted, and asbestos for workers working in the dismantling of buildings, etc. Even when exposure (exposure) occurs, it can be reliably eliminated that the measurement result is not obtained as in the prior art.

  FIG. 5 is a schematic diagram illustrating an example of a measurement result real-time display screen displayed on the display unit 33 of the analysis apparatus 30 in step S403 of FIG.

  A measurement result real-time display screen 330 shown in FIG. 5 is displayed on the display unit 33 by the PC 31 of the analyzer 30. On the measurement result real-time display screen 330, an operation status display area 331, a determination result display area 332, a measurement location display area 333, a latest value display area 334, a two-hour average value display area 335, and a measurement result A display area 336 is arranged.

  In the measurement location display area 333, the location where the concentration measuring apparatus 10 is installed, that is, the measurement location is displayed. By selecting the measurement location display area 333 using a keyboard (not shown) or the like, it is possible to change the measurement location, that is, select the concentration measuring device 10 on which the measurement result of the asbestos concentration should be displayed.

  The operating status display area 331 displays the operating status of the concentration measuring apparatus 10 installed at the measurement location displayed in the measurement location display area 333, for example, “during measurement”. The latest value display area 334 displays the latest value of the measured asbestos concentration. In the 2-hour average value display area 335, the average value of the asbestos concentration measured over 2 hours including the latest value is displayed.

  In the determination result display area 332, the determination result of whether the latest value of the asbestos concentration displayed in the latest value display area 334 is normal or abnormal, that is, the determination result of step S404 in FIG. Is displayed. Further, even when the average value of the asbestos concentration displayed in the 2-hour average value display area 335 is equal to or greater than the threshold value, the determination result display area 332 displays that the determination result is abnormal. In addition, when displaying that it is abnormal, the emphasis display using red, for example is performed.

  In the measurement result display area 336, the measurement result of the asbestos concentration is displayed as a time chart as shown in FIG.

  Further, the PC 31 records the data displayed in each area and the presence / absence of a warning display, the count value received from each concentration measuring device 10, and the like in the recording unit 32 in association with the measurement time. The analysis device 30 may be configured such that the count value received from each concentration measurement device 10 is directly written in the recording unit 32 and the PC 31 reads out the count value recorded in the recording unit 32.

FIG. 6 is a diagram showing an example of the measurement result displayed in the measurement result display area 336 in FIG.
In FIG. 6, the vertical axis indicates the number of particles such as asbestos in the atmosphere, that is, the concentration, and the horizontal axis indicates time.

  A solid line A shown in FIG. 6 indicates a change with time of the asbestos concentration calculated by the process of step S402 of FIG. 4 described above. A two-dot chain line B indicates a change with time in the concentration of particles passing through the flow path 14 in FIG. 2 in the concentration measuring apparatus 10 having the configuration in FIGS. 2 and 3. A chain line C indicates a change with time in the concentration of particles detected when the ash lower part 13 is not used.

  More specifically, in the case of the chain line C, the particles whose concentration is to be measured are all particles included in the dust that has passed through the filtration unit 11. In the case of the two-dot chain line B, among the dusts that have passed through the filtration unit 11. , Particles excluding organic matter, that is, inorganic particles having various shapes. In the case of solid line A, among the dusts that have passed through the filtration unit 11, organic matter and inorganic matter particles other than fibrous particles are included. Excluded particles.

  Therefore, as shown in FIG. 6, it turns out that various particles are contained in the dust contained in air | atmosphere.

  Further, as shown by a chain line C and a two-dot chain line B in FIG. 6, the total number of particles to be measured and the concentration of inorganic particles in all particles are within the working hours from 8 am to 6 pm. Because the dust on the ground surface is exposed to the atmosphere due to the effects of the work and the movement of the workers, it shows a high value that is below the threshold value, while in the atmosphere from 6 pm to 8 am Because the dust exposed to sunk on the ground surface, it shows a very low value.

  On the other hand, the concentration of asbestos shown in the solid line A in the figure does not change regardless of the working time unless there is divergence or exposure, and the number of asbestos particles actually measured is 0 to 1.

  Therefore, a more accurate measurement result of the asbestos concentration can be obtained by selectively extracting the fibrous particles considered to be asbestos.

  FIG. 6 shows an example of measurement results outside (outdoor) the work place 40. On the other hand, a measurement result showing the same tendency can be obtained also in the interior (indoor) of the workplace 40. In this case, the concentration of asbestos is often higher than the concentration of asbestos indicated by the solid line A in FIG. . Therefore, when measuring the asbestos concentration indoors, it is preferable to set a threshold value higher than the threshold value when outdoors.

  In addition, in the measurement result of asbestos concentration as shown in FIG. 6, a pulse-like waveform may appear in which the particle concentration increases sharply and exhibits a concentration equal to or higher than a threshold value. Specifically, the particle concentration increases sharply, and then the waveform in which the particle concentration decreases sharply in a short time, that is, a substantially rectangular pulse waveform, or the particle concentration increases sharply, A waveform in which the concentration of particles attenuates with time, that is, a substantially triangular pulse waveform may be obtained. It is preferable that all waveforms including such waveforms are analyzed in advance and stored in the recording unit 32.

  In waveform analysis, first, statistically analyze each value such as mean value, variance, and standard deviation indicating changes in measurement data (basic data) obtained under conditions that do not show a pulse-like waveform. Next, comparison is made with measurement data obtained under conditions where a pulse-like waveform appears. In addition, based on the relationship between the number of all inorganic particles indicated by the two-dot chain line B in FIG. 6 and the number of asbestos particles indicated by the solid line A, for example, a change in the value of the ratio may be performed. .

  By analyzing such a waveform, for example, the substantially rectangular waveform described above is caused by a measurement abnormality that occurs when the position of the mirror is displaced or the filter is removed, vibrations that occur in the counting unit 20, or the like. It turns out that it is obtained in the case of a mere measurement error, and it turns out that the substantially triangular waveform mentioned above is obtained when dust is suddenly exposed to the atmosphere.

  Then, the partial waveform exhibited by the measurement result as shown in FIG. 6 is compared with the analysis result of the waveform described above to determine whether or not the partial waveform of the measurement result is a waveform indicating dust exposure. As a result, even when it is determined in step S404 that the measured particle concentration is equal to or higher than the threshold, it is possible to eliminate the need for warning display or the like in the case of a measurement abnormality or measurement error. As a result, the user can efficiently take safety measures such as confirmation of the measurement location.

  In the embodiment described above, it is preferable that the concentration measuring apparatus 10 is further configured to be capable of performing comparison and calibration with a conventional asbestos concentration measuring method such as the PCM method. Thereby, the reliability of a measurement result can be improved more.

  Moreover, in the said embodiment, although the asbestos particle | grains which are the fibrous particle contained in the dust in air | atmosphere were mentioned as an example as a measuring object of the density | concentration measuring apparatus 10, another fibrous particle may be sufficient.

1 is a block diagram schematically showing a configuration of a concentration measurement system including a concentration measurement device according to an embodiment of the present invention. It is a block diagram which shows the structure of the density | concentration measuring apparatus in FIG. It is a block diagram which shows the structure of the count part in FIG. 2 in detail. It is a flowchart of the measurement result real-time display process performed in the analyzer in FIG. It is a schematic diagram which shows an example of the measurement result real-time display screen displayed on the display part of an analyzer in step S403 of FIG. It is a figure which shows an example of the measurement result by the density | concentration measuring apparatus displayed on the measurement result display area | region in FIG. It is a timing chart which shows the timing of the asbestos concentration measurement by the conventional PCM method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Concentration measuring system 10 Concentration measuring device 11 Filtration part 12,14 Flow path 13 Ashing part 15 Air pump 20 Count part 21 Laser 29a, 29b Photomultiplier (photomultiplier tube)
29c Identification unit 30 Analysis device 33 Display unit 40 Work place 42 Dust collector 330 Measurement result real-time display screen 333 Measurement location display area 334 Latest value display area 336 Measurement result display area

Claims (12)

In the concentration measuring device that measures the concentration of dust floating in the gas,
A filtration unit that extracts particles having a predetermined size or less from the dust by filtering using a filter;
An ashing section for ashing organic matter;
A pair of electrodes for orienting the dust after passing through the filtration unit and the ashing unit in the direction of an electric field;
A concentration measuring apparatus comprising: a counting unit that counts fibrous particles contained in the dust oriented by the pair of electrodes .   The concentration measuring apparatus according to claim 1, wherein the ashing unit includes at least one of a plasma generator and a heat generator.   The counting unit includes a light irradiation unit that irradiates the dust after passing through the filtering unit and the ashing unit, and a scattered light intensity that measures the intensity of the scattered light of the laser light from the dust. The concentration measuring apparatus according to claim 1, further comprising: a measuring unit; and an identification unit that identifies the fibrous particles from particles included in the dust based on the intensity of the scattered light.   The concentration measuring device according to claim 1, and an analysis device connected to the concentration measuring device and analyzing the dust based on the number of the fibrous particles counted by the counting unit. And a concentration measuring system.   The concentration measuring system according to claim 4, further comprising an operation unit that operates the concentration measuring device.   6. The determination unit according to claim 4, further comprising: a determination unit configured to determine whether or not a concentration of the fibrous particles in the gas is equal to or higher than a predetermined threshold as a result of the analysis of the dust by the analysis device. Concentration measurement system. In the concentration measurement method that measures the concentration of dust floating in the gas using a concentration measurement device,
A filtration step for extracting particles having a predetermined size or less from the dust by filtering using a filter;
An ashing step to ash organic matter;
An alignment step in which the dust after passing through the filtration unit and the ashing unit is aligned in the direction of an electric field by a pair of electrodes;
And a counting step of counting fibrous particles contained in the dust oriented by the pair of electrodes .   The concentration measuring method according to claim 7, wherein at least one of a plasma generator and a heat generator is used in the ashing step.   The counting step includes a light irradiation step for irradiating the dust after the filtration step and the ashing step with laser light, and a scattered light intensity measurement for measuring the intensity of the scattered light of the laser light from the dust. 9. The concentration measuring method according to claim 7, further comprising: a step of identifying the fibrous particles from particles contained in the dust based on the intensity of the scattered light.   The concentration measuring method according to claim 7, further comprising an analysis step of analyzing the dust based on the number of the fibrous particles counted in the counting step.   The concentration measuring method according to claim 7, further comprising an operation step of operating the concentration measuring apparatus.   The determination step of determining whether or not the concentration of the fibrous particles in the gas is equal to or higher than a predetermined threshold as a result of the analysis of the dust in the analysis step. Concentration measurement method.

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