WO2007060969A1

WO2007060969A1 - Floating particle measuring device

Info

Publication number: WO2007060969A1
Application number: PCT/JP2006/323270
Authority: WO
Inventors: Hiroyuki Hattori
Original assignee: Dkk-Toa Corporation
Priority date: 2005-11-28
Filing date: 2006-11-22
Publication date: 2007-05-31
Also published as: JP4839069B2; JP2007147437A

Abstract

[PROBLEMS] To provide a floating particle measuring device capable of eliminating cleaning of a temperature sensor or a humidity sensor for a long period of time and improving measurement accuracy by excluding the affect by fluctuation of the relative humidity. [MEANS FOR SOLVING PROBLEMS] A floating particle measuring device calculates humidity in a detection unit (20) by using temperature in the detection unit (20) and temperature and humidity in a measurement cell (34). A heater unit (35) controls temperature increase/decrease of a sample atmosphere so that the calculated humidity substantially coincide with the set humidity (relative humidity 50%), thereby eliminating the affect by relative humidity fluctuation.

Description

Specification

Airborne particulate matter measurement device

Technical field

[0001] The present invention relates to a suspended particulate matter measuring apparatus for measuring suspended particulate matter concentration in a gas.

Background art

[0002] Suspended Particulate Matter (SPM) refers to solid and liquid particles with a diameter of 10 m (l μm = lmm / thousand) or less among particles suspended in the atmosphere. It is. This suspended particulate matter is generated by man-made sources such as smoke generation facilities and exhaust particles from automobiles, or by natural sources such as soil and pollen, and is also generated in the atmosphere. It is under physical and physical action. Its main components are heavy metal elements (Fe, Cu, Pb, Zn, etc.), inorganic acid salts (SO ^2_ , ^NO- ),

4 3 Contains carbon compounds. By the way, suspended particulate matter is sometimes called aerosol.

In Japan, particles with a particle size of 10 / zm or more are defined as 100% cut and are referred to as “SPM”. However, overseas, particles with a particle size of 10 μm or more are defined as 50% cut and “Ρ Μ10 "

[0003] Since these suspended particulate matter is considered to be the cause of air pollution that affects the respiratory tract, such as being deposited in the lungs and respiratory organs, environmental standards (for protecting human health) The standard is preferably maintained), and the concentration of suspended particulate matter is 0. lOmgZm ³ or less at the daily average of 1 hour value and 0.20 mgZm ³ or less at 1 hour value. It is stipulated.

[0004] In recent years, among suspended particulate matter, particles with a particle size of 10 m or less (hereinafter referred to as “SPM”, which is a 100% cut of particles of 10 m or more, 10 μm or more particles) Is replaced with “PM10”). Particles with a particle size of 2.5 m or less (hereinafter referred to as 2.5 / zm or more) are cut with 50%. ”) Is being emphasized as a measurement target. [0005] Now, as a means of measuring the suspended particulate matter SPM, PM10 or PM2.5 in the atmosphere, the suspended particulate matter is collected on a filter paper, and its mass is measured using an 8-line absorption method or the like. Suspended particulate matter measuring devices that measure the concentration are well known.

According to this suspended particulate matter measuring apparatus, it is possible to fully automate a series of measurement operations including collection and concentration measurement of suspended particulate matter.

[0006] The prior art of such a suspended particulate matter measuring device will be described with reference to the drawings. FIG. 4 is an explanatory view of the main part of the prior art suspended particulate matter measuring device (example of PM10). As shown in FIG. 4, the measurement unit of the suspended particulate matter measuring apparatus 1000 includes a detection unit 101, a j8 radiation source 102, a semiconductor detector 103, a scraping reel 201, a filter paper 202, a capstan 203, a feed reel 204, and a motor. 205, a particle separator (for PM10) 301, a pipe 302, a pipe 303, and a pump 304.

[0007] Measurement processing by this suspended particulate matter measuring device will be described.

The suction of pump 304 causes the sample atmosphere to flow along the path of the particle separator 301, self-pipe 302, detection unit 101, self-pipe 303, and pump 304, and the sample atmosphere containing suspended particulate matter is introduced into the detection unit 101. Is done. A filter paper 202 is arranged in the detection unit 101, and the filter paper 202 collects floating particulate matter. The collected sample air is exhausted through a pipe 303 and a pump 304.

[0008] The suspended particulate matter concentration is measured by the β-ray absorption method for the suspended particulate matter. The concentration measurement by this β-ray absorption method will be described.

Although it is the measurement principle, ι8 line intensity I when passing through the latest filter paper 202 in which suspended particulate matter is not collected, and filter paper 202 in the state where suspended particulate matter is collected

0

Β-ray intensity I, β-ray absorption cross section k per unit mass of suspended particulate matter, mass m of particles per unit area of filter paper 202, total collection area S, integrated suction Using the flow rate V, the suspended particulate matter concentration M is expressed by the following equation.

[0009] [Equation 1]

M = (m / V) = (S / k V) I n (I. / I) [0010] These S, k, V are registered in advance in a memory unit (not shown), and β-ray intensity I, β-ray intensity I

0

Is detected and the suspended particulate matter concentration Μ is calculated.

[0011] The concentration calculation means of the CPU board (not shown) first inputs a detection signal representing | 8-line intensity I when the latest filter paper 202 that has not been collected is passed to the memory unit. sign up. Continued

0

Then, a detection signal indicating β-ray intensity I passing through the filter paper 202 that collects suspended particulate matter over a predetermined period is input. At this time, in the detection unit 101, when β rays are emitted from the j8 radiation source 102 to the collected suspended particulate matter, a part of the β rays is absorbed by the suspended particulate matter on the filter paper 202, Unabsorbed and powerful β-rays are input to the semiconductor detector 103. The semiconductor detector 103 outputs a detection signal proportional to the 13-line intensity. The detection signal representing the 13-line intensity I is input by the concentration calculation means and registered in the memory unit. Concentration calculation means reads out S, k, V, I, I from the memory section and performs the calculation according to the above equation (1) to obtain suspended particulate matter.

0

The concentration M (mg / m ³ ) is calculated.

[0012] Then, after the measurement is completed, the motor 205 is driven by the driving means of the CPU board (not shown) to rotate the take-up linole 201. capstan 203 force S, and feed out the feed linole 204 force and the paper 202 force S. As the new part is set, the scraping reel 201 accommodates the used part of the filter paper 202.

The outline of the suspended particulate matter measuring apparatus 1000 is as described above.

[0013] Now, in such a suspended particulate matter measuring apparatus, it is known that measurement accuracy is affected by humidity. Atmospheric force with high humidity When collected sample air is used, water and suspended particulate matter containing water are also collected on the filter paper 202. This moisture has the function of shielding β rays.

For this reason, in addition to the absorption of the j8 line by suspended particulate matter, the moisture does not pass through the j8 line and the β-ray intensity reaching the semiconductor detector 103 is reduced, and when the humidity is high, it floats more than it actually is There is a risk of measuring the particulate matter concentration high. Therefore, in the conventional technology, the humidity of the sample atmosphere is generally suppressed to a predetermined value or less to eliminate the influence of humidity. For example, in Non-Patent Document 1 related to a foreign paper, the sample atmosphere is measured by a heater 30 It is stated that heating up to ° C reduces the humidity to below 60%. The

Patent Document 1 describes a dust radiation monitor having a configuration similar to that of a suspended particulate matter measuring device, and describes that the temperature is raised by a heater in order to remove the influence of humidity. In Patent Document 1, in order to improve the measurement accuracy, the filter paper is dried in order to facilitate the feeding of the filter paper.

[0014] As another example of the prior art, the temperature and humidity are controlled to a predetermined value by detecting the temperature and humidity of the sample atmosphere and sample gas and adjusting the temperature and humidity of the sample gas flow to a predetermined value. There is something.

Patent Document 2 includes a sensor that detects the temperature and humidity of a sample gas and a sensor that detects the temperature and humidity of the atmosphere, and controls the temperature and humidity to predetermined values using detection signals of these sensor forces. is doing.

[0015] Non-Special Reference 1: Albert Chung et al. Comparison of Real-Time Instruments Used To

Monitor Airborne Particulate Matter ", Journal of the Air & Waste Management Asso ciation, JANUARY, VOLUME 51, Number 1, pi 09— pi 20

Patent Document 1: Japanese Patent Laid-Open No. 7-244163 (paragraph number 0017, FIG. 1)

Patent Document 2: Japanese Patent No. 3362255 (Fig. 1)

Disclosure of the invention

Problems to be solved by the invention

[0016] The suspended particulate matter measurement may be performed by manual analysis, and the conditioning condition before weighing the filter paper in this manual analysis is 50% humidity. Therefore, it is desirable to measure the filter paper 202 under the conditioning condition of 50% humidity even with the suspended particulate matter measuring device.

However, in the prior art suspended particulate matter measuring device, the suspended particulate matter concentration M is measured at a relative humidity of a predetermined value or less (for example, relative humidity of 60% or less). For example, the relative humidity is 30%, Measurement was possible even in the case of 50%. If the humidity of the sample atmosphere is lower than the humidity condition of 50%, which is the conditioning condition for manual prayer (for example, 30%), the humidity in the detection unit 101 also becomes lower, and the moisture of the collected particles is absorbed. The rate was different and there was a problem that it was different from the suspended particulate matter concentration M by manual analysis. If the suspended particulate matter measurement device can obtain the same suspended particulate matter concentration M as in the manual analysis, Since it is possible to perform automatic measurement with high accuracy, there has been a demand for improvement.

[0017] Therefore, if the relative humidity of the sample atmosphere is measured at 50%, which is the conditioning condition of the manual analysis value, in order to match the β-ray absorption method analysis value and the manual analysis value, the measurement is made to match the manual analysis value. Although improvement in accuracy can be expected, it was difficult to measure the suspended particulate matter using the current β-ray absorption method after eliminating the effects of fluctuations in relative humidity. The monitor is intended to dry the filter paper and lower the relative humidity significantly. There was a problem that the suspended particulate matter concentration was measured below the manual analysis value when the relative humidity was lower than 50%. .

[0018] Also, in the apparatus in Patent Document 2, the relative humidity can be reduced to 50% by adjusting the temperature and humidity, but the measurement performance of the atmospheric temperature sensor and the atmospheric humidity sensor is quickly deteriorated. There was a problem. For example, in the apparatus in Patent Document 2, an atmospheric temperature sensor and an atmospheric humidity sensor are exposed to the atmosphere, and the temperature and humidity of the atmosphere are measured. In this case, suspended particulate matter in the atmosphere adheres to and accumulates on the surfaces of the atmospheric temperature sensor and atmospheric humidity sensor, which degrades the measurement performance.

Therefore, both the air temperature sensor and the air humidity sensor require periodic cleaning (cleaning once every two weeks to once a month, depending on the contamination situation at the site). There was a problem that cleaning and recalibration had to be performed, which required considerable labor in terms of operation and maintenance. In addition, there is a risk of missing data during cleaning work.

[0019] Further, as a humidity sensor, there is also a ceramic humidity sensor having a cleaning function by heating with a heater. There is a demand to use a capacitance type RH sensor which is inexpensive and widely used.

In the case of this RH sensor, it is necessary to wash it with alcohol, detergent, water, etc. and dry it in order not to blow off dust with air or damage the sensor's electrical wiring. It was difficult to do this, and there was a problem that it took time to clean as described above.

Conditions such as these: Airborne particles in the atmosphere adhere to the temperature sensor and humidity sensor. There was a request to make the cleaning work unnecessary as much as possible and to enable measurement over a long period of time.

[0020] Therefore, the present invention has been made to solve the above-described problems, and its purpose is to eliminate the need for cleaning the temperature sensor and the humidity sensor over a long period of time and to eliminate the influence of fluctuations in relative humidity. The object is to provide a suspended particulate matter measurement device that improves measurement accuracy.

Means for solving the problem

[0021] Such a suspended particulate matter measuring device according to claim 1 of the present invention includes:

Sample air collection means for collecting sample air containing suspended particulate matter having a particle size of a predetermined particle size or less by suction means; and

A collection means for continuously collecting suspended particulate matter from the sample atmosphere;

A collection unit having suspended particulate matter collected by the collection unit, and a detection unit that irradiates the collection unit with β-rays and outputs a detection signal corresponding to the transmitted 13-line intensity;

Upstream temperature measuring means for measuring the temperature of the sample atmosphere at the time of collection by the collecting means upstream of the suction means and outputting an upstream temperature signal; and

Downstream temperature measuring means for measuring the temperature of the sample atmosphere after being collected by the collecting means on the downstream side of the suction means and outputting a downstream temperature signal; and

Downstream humidity measuring means for measuring the humidity of the sample atmosphere after being collected by the collecting means on the downstream side of the suction means and outputting a downstream humidity signal;

Based on the upstream temperature signal from the upstream temperature measurement means, the downstream temperature signal from the downstream temperature measurement means, and the downstream humidity signal from the downstream humidity measurement means, the upstream side of the suction means and the upstream side. Upstream-side humidity calculating means for calculating upstream-side humidity at the location where the side temperature is measured;

Driving means for outputting a driving signal for causing the upstream humidity of the sample atmosphere to substantially match the set humidity based on the upstream humidity calculated by the upstream humidity calculating means;

Humidity adjustment means that adjusts the humidity of the sample atmosphere based on the drive signal of the drive means force and β-ray absorption based on the detection signal from the detection means in an environment approximately equal to the set humidity Concentration calculating means for calculating the suspended particulate matter concentration by a method;

It is characterized by providing.

[0022] In addition, the suspended particulate matter measuring device according to claim 2 of the present invention includes:

In the suspended particulate matter measuring device according to claim 1,!

The upstream temperature measuring means for measuring the upstream temperature is a means that is disposed integrally with the detecting means and measures the temperature of the sample atmosphere when collected by the collecting means in the vicinity of the collecting part. It is characterized by being.

[0023] Further, the suspended particulate matter measuring device according to claim 3 of the present invention includes:

3. The suspended particulate matter measuring device according to claim 1 or 2, wherein the downstream temperature measuring means and the downstream humidity measuring means are provided at the most downstream side of the flow path of the sample air sampling means. It is characterized by having a receiving means for storing in the space.

[0024] In addition, the suspended particulate matter measuring device according to claim 4 of the present invention includes:

In the suspended particulate matter measuring device according to claim 3,

The internal space of the accommodating means is enlarged so that the pressure in the internal space approaches the atmospheric pressure.

[0025] Further, the suspended particulate matter measuring device according to claim 5 of the present invention is

The suspended particulate matter measuring device according to any one of claims 1 to 4, wherein the humidity adjusting unit is a unit that adjusts humidity by raising or lowering a sample atmosphere. To do.

The invention's effect

[0026] According to the present invention as described above, the suspended particulate matter measurement apparatus that eliminates the effect of fluctuations in relative humidity without the need for cleaning the temperature sensor and the humidity sensor over a long period of time and improves the measurement accuracy. Can be provided.

BEST MODE FOR CARRYING OUT THE INVENTION

[0027] Next, the suspended particulate matter measuring device of the best mode for carrying out the present invention will be described with reference to the drawings. Fig. 1 shows the configuration of the suspended particulate matter measurement device (example of PM10) 1 in this form, Fig. 2 shows the internal configuration of the storage unit, and Fig. 3 shows the | 8-line absorption method based on relative humidity. It is a characteristic figure explaining the error of an analysis value and a manual analysis value. In addition, although a part overlaps with a prior art, it attaches a new code | symbol and demonstrates again.

[0028] The suspended particulate matter measuring device 1 includes a CPU board 11, an operation panel 12, a recorder 13, an I / O board 14, a power IZO board 15, an amplifier board 16, an external input / output terminal 17, and a detection mute. 20, j8 radiation source 21, semiconductor detector 22, feed reel 23, capstan 24, take-up reel 25, granulator (for PM10) 26, pump 27, flow sensor 28, piping 29, 30, 31, downstream temperature Sensor 32, downstream humidity sensor 33, measurement cell (temperature / humidity measurement cell) 34, heater unit 35, upstream temperature sensor 36, filter paper 40, motor Ml, motor M2, and motor M3 are provided. These are broadly classified as sample air sampling means, collection means, detection means, upstream temperature measurement means, downstream temperature measurement means, downstream humidity measurement means, storage means, upstream humidity calculation means, drive means, humidity. It becomes an adjustment means and a density calculation means. Each means is described below

First, the sample air sampling means will be described. The sample air sampling means uses a suction means to reduce the particle size to a predetermined particle size (SPM: 10 m (10 m or more, 100% cut), PM10: 10 111 (10 111 or more, 50% cut), 1 ^ 2.5 is a means to collect sample air containing suspended particulate matter that is 2.5 μ ηι (cut by 50% at 2.5 m or more). Granulator (for PM10) 26, piping 29, detection unit 20, filter paper 40, piping 30, pump 27 (specific example of suction means of the present invention), piping 31, flow sensor 2 8, measurement cell 34 When pump 27 performs a suction operation, the sample air is passed through granulator 26 → piping 29 → detection unit 20 → filter paper 40 → pipe 30 → pump 27 → pipe 31 → flow sensor 28 → measurement cell 34. Exhausted to the outside.

[0030] The detection unit 20 is formed of an upper block 20a and a lower block 20b each having a substantially rectangular parallelepiped shape. The upper block 20a is provided with a flow path connected to the pipe 29, and the lower block 20b has an upper side. A lower flow path is provided so as to face the flow path. A filter paper 40 is located between the upper block 20a and the lower block 20b.

In such a flow path system, a flow rate sensor 28 is disposed downstream of the pump 27, and the flow rate of the flowing sample atmospheric gas is accurately measured to output a flow rate signal. The flow sensor 28 is, for example, a thermal flow sensor. The flow rate signal output from the flow sensor 28 The number is input to the CPU board 11 via the I / O board 14. Furthermore, a valve is provided in the flow path that bypasses the pump 27, and this valve is connected to a motor M3 for stabilizing the flow rate. The motor is driven by a drive signal from the CPU board 11 via the IZO board 14. M3 is driven to control the opening and closing of the valve. With such a configuration, the flow rate is made constant, and the integrated suction flow rate V mentioned in the previous equation 1 is made accurate. As a result, the granulator 26 sucks the sample air at a constant flow rate.

[0032] The particle sizer 26 (for PM10) is an impactor type particle sizer that performs, for example, PM 10 particle size classification using inertial collision of coarse particles in the sample atmosphere, and removes coarse particles from the sample atmosphere. Obtain a sample atmosphere through which airborne particles with a particle size of 10 μm or less (50% cut) are passed.

For PM2.5 (floating particles with a particle size of 2.5 m), a cyclone-type or impactor-type granulator is installed in the subsequent stage to selectively select particles of 2.5 m or less. It may be sized. These are appropriately selected according to the measurement object.

[0033] The sample atmosphere containing such suspended particulate matter passes through the collection means.

The collection means is means for continuously collecting suspended particulate matter from the sample atmosphere. For example, as in this embodiment, it is provided with a feed reel 23, a capstan 24, a take-up reel 25, a filter paper 40, a motor M1, and a motor M2. The drive signals of motor Ml and motor M2 are output from CPU board 11 via power IZO board 15.

The tape-shaped filter paper 40 can be fed by a feed reel 23 that supplies unused filter paper 40 and a scraping reel 25 that winds and stores used filter paper 40 in a roll. A fixed length is supplied into the detection unit 20.

The motor M1 moves the lower block 20b of the detection unit 20 up and down and opens and closes the filter paper 40 for trapping suspended particulate matter transported in the detection unit 20, and the motor M2 is an open / close operation motor. This is a motor for feeding filter paper 40. When the detection unit 20 is opened by the motor Ml, the filter paper 40 is rotated after the take-up reel 25 and the capstan 24 by the motor M2, so that the filter paper 40 is passed after a certain period (for example, every hour). The unused portion is fed into the detection unit 20 through the feed reel 23 and the capstan 24 and is accommodated in the scraping reel 25 by the same length.

[0034] The detection means irradiates the suspended particulate matter collected by the collection means with β-rays and transmits the β It is a means for outputting a detection signal for the line intensity. For example, as in this embodiment, a j8 source 21, a semiconductor detector 22, and an amplifier board 16 are provided. The output signal of the semiconductor detector 22 is amplified by an amplifier in the amplifier board 16 and input to the CPU board 11 via the IZO board 14.

A β-ray source 21 is provided in the upper block 20a of the detection unit 20, and a semiconductor detector 22 is provided in the lower block 20b so as to face the β-ray source 21, and the flow path and the radiation direction described above are provided. Are arranged to intersect. The filter paper 40 passes between the upper block 20a and the lower block 20b. The detection principle of the detection means adopts the β-ray absorption method as in the prior art described above, and redundant description is omitted.

[0035] The upstream temperature measuring means is a means for measuring the temperature of the sample atmosphere when the suspended particulate matter is collected by the collecting means on the upstream side of the suction means and outputting an upstream temperature signal. The The upstream side is preferably arranged integrally with the detection means, and the temperature of the sample atmosphere when being collected by the collection means is determined by the collection of the suspended particulate matter collected by the collection means. As a means for measuring in the vicinity of the part. The upstream temperature measuring means is the upstream temperature sensor 36 in this embodiment. The upstream temperature sensor 36 is located between the filter paper 40 and the pump 27, and is disposed in the vicinity of the collection part 40a, which is a part of the filter paper 40 where floating particulate matter is collected. Is a temperature sensor inside the unit that detects the temperature inside the unit and is arranged near the semiconductor detector 22 on the lower block 20b side of the detection unit 20 through which the clean air flow that has passed through the filter paper 40 flows. The in-unit temperature signal output from the upstream side temperature sensor 36 is input to the CPU board 11 via the IZO board 14.

[0036] The downstream temperature measuring means is a means for measuring the temperature of the sample air after the suspended particulate matter is collected by the collecting means on the downstream side of the suction means and outputting a downstream temperature signal. The The downstream temperature measuring means is the downstream temperature sensor 32 in this embodiment. More specifically, the downstream temperature sensor 32 is disposed in a measurement cell 34 that is downstream of the pump 27 and is downstream of the flow path system. The downstream temperature sensor 32 is an in-cell temperature sensor that detects the temperature in the measurement cell in the measurement cell 34 in which a clean air flow that has passed through the filter paper 40 flows. The in-cell temperature signal output from the downstream temperature sensor 32 is Input to the CPU board 11 via the IZO board 14!

[0037] The downstream humidity measuring means is a means for measuring the humidity of the sample air after the suspended particulate matter is collected by the collecting means on the downstream side of the suction means and outputting a downstream humidity signal. The The downstream humidity measuring means is the downstream humidity sensor 33 in this embodiment. In detail, the downstream humidity sensor 33 is disposed in the measurement cell 34 which is downstream of the pump 27 and further downstream of the flow path system. The downstream humidity sensor 33 is a cell humidity sensor that detects the humidity in the measurement cell in the measurement cell 34 in which clean airflow that has passed through the filter paper 40 flows. The in-cell humidity signal output from the downstream humidity sensor 33 is input to the CPU board 11 via the I / O board 14.

The accommodating means is a means that is provided on the most downstream side of the flow path of the sample air sampling means, and accommodates the downstream temperature measuring means and the downstream humidity measuring means in the internal space. In this embodiment, as shown in FIG. 1 and particularly FIG. As shown in FIG. 2, the measurement cell 34 includes a cell body 341, a seal 342, a gas inlet 343, and a gas outlet 344. The downstream temperature sensor 32 and the downstream humidity sensor 33 are fixed in a state where they are accommodated in an internal space of the glass cell main body 341 while being sealed by a seal 342. The cell body 341 has a large internal space, and the high-pressure sample gas introduced from the gas inlet 343 enters the large volume of the internal space to reduce the pressure and bring it closer to the atmospheric pressure. Exhaust after passing through. The downstream temperature sensor 32 and the downstream humidity sensor 33 are disposed immediately before the gas outlet 3 44, and there is almost no flow path resistance between the glass cell body 341 and the gas outlet 344. The point in the measurement cell is also close to atmospheric pressure. In addition, since the flow rate flowing into the cell main body 341 by the force flow sensor 28 described above is a constant amount, it is considered that the internal pressure in the measurement cell 34 does not fluctuate. As a result, the temperature and humidity of the sample atmosphere in a state close to atmospheric pressure in the measurement cell 34 can be acquired.

[0039] The upstream humidity calculation means is configured to convert the upstream temperature signal from the upstream temperature measurement means, the downstream temperature signal from the downstream temperature measurement means, and the downstream humidity signal from the downstream humidity measurement means. Based on this, it is a means for calculating the upstream humidity in the vicinity of the collecting part for measuring the upstream temperature upstream of the suction means. For example, in this embodiment, CPU board 11, Panel 12, recorder 13, IZO board 14, power ΙΖΟ board 15, external input / output terminal 1 7 and CPU board 11 program calculation, temperature signal in the boot from upstream temperature sensor 36, downstream Based on the temperature signal in the cell from the side temperature sensor 32 and the humidity signal in the cell from the downstream humidity sensor 33, the location where the unit temperature is measured upstream of the pump 27 (upstream temperature sensor This is a means for calculating the humidity inside the unit in the vicinity of the place where 36 is installed. Details of upstream humidity calculation will be described later.

[0040] The drive means is means for outputting a drive signal for making the upstream humidity of the sample atmosphere substantially coincide with the set humidity based on the upstream humidity calculated by the upstream humidity calculation means. For example, in this embodiment, the CPU board 11, operation panel 12, recorder 13, IZO board 14, power I / O board 15, external input / output terminal 17 are provided. Outputs a drive signal that makes the internal humidity approximately equal to the set humidity (50% relative humidity). The drive means has the same configuration as the upstream humidity calculation means described above. Details of driving will be described later.

[0041] The humidity adjusting means is means for changing the humidity of the sample atmosphere based on the drive signal from the drive means. For example, in this embodiment, the heater unit 35 raises or lowers the temperature of the sample atmosphere. The drive signal output from the CPU board 11 and amplified by the power I / O board 15 is input to the heater unit 35.

[0042] The concentration calculation means is means for calculating the concentration of suspended particulate matter by the β-ray absorption method based on the detection signal from the detection means. For example, in this embodiment, the CPU board 11, the operation panel 12, the recorder 13, IZO board 14, power ΙΖΟ board 15, external input / output terminal 17 are provided, and density calculation is performed by CPU board 11 program processing. This concentration calculation means has a common configuration for the upstream humidity calculation means and drive means described above. The concentration calculation will be described in detail later.

[0043] Next, among the operations of the suspended particulate matter measuring device 1, humidity adjustment will be described with reference to the drawings. The characteristic diagram in Fig. 3 shows the error between the β-ray absorption method analysis value and the manual analysis value due to relative humidity, and the β-ray absorption method at atmospheric pressure and relative humidity of 50%, which is the conditioning condition for manual analysis. The suspended particulate matter concentration による due to coincides with the suspended particulate matter concentration による due to manual analysis. Therefore, the relative humidity of 50% is maintained as a conditioning condition. By doing so, the same value as the manual analysis is obtained, and the measurement accuracy can be improved. However, since the inside of the detection unit 20 is under reduced pressure due to the vacuum suction of the pump 27, even if the humidity in the detection unit 20 is detected as it is, it is different from the humidity under atmospheric pressure, and some adjustment is made. Otherwise, it cannot be used for humidity adjustment. In general, the humidity sensor is larger than the temperature sensor and is not easily installed in the detection unit 20, as is apparent from the comparison between the downstream temperature sensor 32 and the downstream humidity sensor 33 in FIG. There was a problem.

Therefore, a temperature sensor much smaller than the humidity sensor is installed in the detection unit 20, and the relative humidity under atmospheric pressure is calculated from the detected temperature in the detection unit 20 to calculate the humidity in the unit. Based on the internal humidity, the humidity is adjusted so that the relative humidity of the detection cell 20 is 50%.

Next, the operation of each unit that performs humidity adjustment during detection will be described.

It is assumed that the sample air is introduced to the detection unit 20 through the granulator 26 and the pipe 29 by the operation of the pump 27, and the suspended particulate matter is collected on the surface of the filter paper 40. Under such circumstances, adjust the humidity to the sample atmosphere!

The upstream temperature sensor 36 measures the temperature of the sample atmosphere in the detection unit 20 and outputs a unit temperature signal. The CPU board 11 calculates the unit internal temperature based on the unit internal temperature signal, and calculates the unit saturated water vapor pressure using the following equation.

[0047] The downstream temperature sensor 32 measures the temperature of the sample atmosphere in the measurement cell 34 and outputs an in-cell temperature signal. The CPU board 11 calculates the in-cell temperature based on the in-cell temperature signal, and calculates the in-cell saturated water vapor pressure as in the following equation.

[0048] [Equation 3] 7.5 X cell temperature / (237.3 + cell temperature)) Saturated saturated water vapor pressure = 6. 11 X 10

The downstream humidity sensor 33 measures the humidity of the sample atmosphere in the measurement cell 34 and outputs a humidity signal in the cell. CPU board 11 is a cell based on the humidity signal in the cell. Calculate the relative humidity inside.

Subsequently, the CPU board 11 functions as upstream humidity calculation means, and calculates the in-unit relative water vapor pressure, the in-unit saturated water vapor pressure, and the in-cell humidity force obtained previously as in the following equation.

[0050] Relative humidity in unit = relative humidity in cell X saturated water vapor pressure in cell / saturated water vapor pressure in unit

Thereby, the relative humidity in the unit is calculated. In CPU board 11, the relative humidity (set humidity) set in advance in the memory unit (not shown) is registered as 50%.

When the calculated relative humidity in the unit is higher than 50%, the CPU board 11 functions as a drive means for driving the humidity adjustment means, and the heater unit 35, which is the humidity adjustment means, is driven to rise through the power IZO board 15. To do. Then, the temperature of the sample air rises and the relative humidity decreases, and the relative humidity in the unit of the sample air is maintained at 50%.

On the other hand, when the calculated relative humidity in the unit is lower than 50%, the CPU board 11 functions as a driving means for driving the humidity adjusting means, and the heater unit 35 that is a humidity adjusting means is connected via the power IZO board 15. Drive down the temperature. Then, the temperature of the sample atmosphere drops and the relative humidity increases, and the relative humidity of the sample atmosphere is maintained at 50%. These samples are heated and lowered only when necessary.

Thereafter, the same humidity adjustment is performed automatically in sequence, so that the relative humidity in the unit matches the set humidity.

[0052] In the description of the present embodiment, the set humidity is 50% in order to match the manual analysis value, but a different value may be adopted for the purpose of limiting the humidity to 50%. For example, in the overseas, the manual analysis conditioning conditions described above are 30% to 40%, and the set humidity may be set to 30% to 40% as necessary. These set humidity can be changed appropriately according to the circumstances.

[0053] Subsequently, continuous measurement of the concentration of suspended particulate matter in the atmosphere with the relative humidity kept constant as described above by the suspended particulate matter measuring apparatus will be described.

When the operator operates the operation panel 12, the operation signal force is such that measurement starts. Is input to mode 11. The CPU board 11 outputs a control signal to each part. At this time, the uncollected portion of the filter paper 40 is already placed on the detection unit 20 and is firmly sandwiched between the upper block 20a and the lower block 20b and sealed so that the j8 line does not leak. . First, | 8 rays are emitted from the j8 source 21. Then, the detection signal from the semiconductor detector 22 is temporarily stored in the memory unit of the CPU board 11. The detection signal stored first is β-ray intensity I

0.

Subsequently, a drive signal is output to the pump 27 via the ΙΖΟ board 14. The sample atmosphere is aspirated from the atmosphere, and sampling of the sample atmosphere is started. In this case, as described above, the flow rate signal from the flow rate sensor 28 is input to the CPU board 11 via the 14 board 14, and a drive signal that maintains a predetermined set flow rate is sent to the motor via the IZO board 14. This is sent to M3, and the valve is controlled to open and close by motor Μ3, and the flow rate is adjusted to the predetermined set flow rate.

[0054] Then, when the pump 27 operates for a predetermined time and the sample atmosphere at a predetermined flow rate is sucked, the CPU board 11 stops the operation of the pump 27, and the collection of the sample atmosphere is stopped. Next, | 8 rays are irradiated again by j8 source 21. The detected signal power from the semiconductor detector 22 is temporarily stored in the memory of the CPU board 11. This detection signal is j8 line intensity I.

Then, in addition to the j8 line intensity I and j8 line intensity I registered in the memory, the above constants S, k, V are read.

0

Based on the above formula 1, the suspended particulate matter concentration 線 is calculated by the β-ray absorption method. The CPU board 11 records the suspended particulate matter concentration に on the recorder 13.

After recording is completed, the filter paper 40 is moved. First, the CPU board 11 drives the motor Ml via the IZO board 14 and the power IZO board 15 to lower the lower block 20b of the detection unit 20 so that the filter paper 40 can be moved. Subsequently, the CPU board 11 drives the motor 2 through the IZO board 14 and the power board 15 to send the filter paper 40, and places the unused part in the detection unit 20. Then, the lower block 20b rises and returns to the initial state, and thereafter, the same operation is repeated to automatically measure suspended particulate matter.

As described above, the suspended particulate matter measuring device 1 according to the present embodiment has been described. It should be noted that the set humidity described above is a force described as being pre-registered in the memory unit of the CPU board 11. For example, it may be possible to newly register in the memory unit of the CPU board 11 via the operation panel 12. Good.

Also, the suspended particulate matter concentration M has been described as being recorded on the recorder 13. However, a display unit (not shown) connected to the IZO board 14 is further mounted to display the suspended particulate matter concentration M. A form may be added. Furthermore, it is possible to add a form in which data can be output to the storage unit so that it can be connected to or mounted on a hard disk, a magneto-optical disk, or a USB memory.

As described above, according to the suspended particulate matter measuring device of the present invention, instead of the method of directly detecting the temperature and relative humidity of the sample atmosphere from the atmosphere, the sample atmosphere collecting means for collecting and releasing the sample atmosphere The system detects the temperature and humidity at the most downstream side. The sample atmosphere after collection of suspended particulate matter by the collection means is free of suspended particulate matter! It is a flow of clean air. Even for long-term measurements, the upstream temperature sensor, downstream temperature sensor, Any downstream humidity sensor is hardly contaminated, and can maintain a clean state semipermanently.

[0057] Further, since the temperature sensor, which is generally small, is arranged in the detection unit, the detection unit is not required to be downsized and the humidity sensor is not cleaned, so that disassembly and maintenance are unnecessary. .

In addition, by maintaining certain selectable humidity and temperature conditions, it is possible to eliminate differences from the manual analysis of standard measurement methods in the measurement of particulate matter due to the influence of humidity and temperature.

Brief Description of Drawings

[0058] FIG. 1 is a configuration diagram of a suspended particulate matter measuring apparatus (example of PM10) of the best mode for carrying out the present invention.

FIG. 2 is an internal configuration diagram of the storage unit.

FIG. 3 is a characteristic diagram illustrating an error between the β-ray absorption method analysis value and the manual analysis value due to relative humidity.

圆 4] It is an explanatory view of the main part of the prior art suspended particulate matter measuring device.

Claims

The scope of the claims

[1] Sample air sampling means for collecting sample air containing suspended particulate matter having a particle size of a predetermined particle size or less by suction means;

The humidity adjustment means that adjusts the humidity of the sample atmosphere based on the drive signal of the drive means force. Under an environment that is approximately equal to the set humidity, the suspended particulate matter concentration is determined by the β-ray absorption method based on the detection signal from the detection means Concentration calculating means for calculating;

A suspended particulate matter measuring device comprising:

[2] In the suspended particulate matter measuring device according to claim 1,!

The upstream temperature measuring means for measuring the upstream temperature is a means that is disposed integrally with the detecting means and measures the temperature of the sample atmosphere when collected by the collecting means in the vicinity of the collecting part. A suspended particulate matter measuring apparatus characterized by

[3] In the suspended particulate matter measuring device according to claim 1 or claim 2, Floating particulate matter, characterized in that it is provided on the most downstream side of the flow path of the sample air sampling means, and includes a storage means for storing the downstream temperature measurement means and the downstream humidity measurement means in an internal space. measuring device.

[4] In the suspended particulate matter measuring device according to claim 3,

The suspended particulate matter measuring device characterized in that the internal space of the housing means is enlarged to bring the pressure in the internal space close to atmospheric pressure.

[5] The suspended particulate matter measuring device according to any one of claims 1 to 4, wherein the humidity adjusting means adjusts the humidity by increasing or decreasing the temperature of the sample atmosphere. A suspended particulate matter measuring apparatus characterized by