KR20100052691A - Measuring apparatus and method of multi gas pollutants using the ndir detector with multi gas filter - Google Patents

Abstract

PURPOSE: Measurement device and method of a variety of contamination materials using a non-dispersive infrared ray detector with a multi gas filter are provided to measure and analyze a variety of contamination materials to effectively process a lot of data in real time, by classifying the kind of an air contamination materials and analyzing the concentration. CONSTITUTION: A measurement device of a variety of contamination materials using a non-dispersive infrared ray detector with a multi gas filter comprises an infrared radiant light(10), a gas correlation filter(11), an absorption chamber(14) and an infrared sensor(16). At the gas correlation filter, a number of filter channels(13) are formed so that the reference cell and the measurement cell are alternately arranged in the circumferential direction to simultaneously measure a variety of contamination materials. The mixed sample gas in which a variety of air contamination materials are mix is stored inside the absorption chamber. The absorption chamber has the multi light path formed by a reflection mirror installed at the inside and the gas correlation filter. The infrared sensor measures the infrared absorption energy of the filter channel. From the infrared absorption signal of each filter channel measured by the infrared sensor, the concentration of each measurement substance is obtained by calculating the absorption difference between the output signal of a measurement cell and the signal of a reference cell by each measurement material.

Description

Measuring apparatus and method of multi gas pollutants using the NDIR detector with multi gas filter}

The present invention relates to an apparatus and method for measuring multiple pollutants using a non-dispersion infrared detector, and more particularly, to a non-dispersion which can simultaneously measure various types of air pollutants in real time using non-dispersion infrared analysis (NDIR). The present invention relates to a multi-pollutant measuring device and method using an infrared detector.

As the most practical measurement technique for measuring the concentration of gaseous air pollutants emitted from a business chimney in real time, a measurement technique using non-dispersive infrared method (NDIR) is applied.

Recently, as various kinds of pollutants are released into the atmosphere due to industrialization, analysis of various kinds of pollutants in real time is required.

Certain air pollutants have absorption characteristics in the intrinsic wavelength band of the infrared (IR) region, and are exponentially proportional to the product of infrared transmission distance and sample concentration by Beer-Lambert's law.

The analytical method using these characteristics is called NDIR method and is mainly used to measure the concentration of atmospheric emissions such as carbon monoxide, sulfur oxides, and nitrogen oxides (CO, SO2, NOx.) [3]. The NDIR optical analyzer with gas filter correlation (GFC) generates a monochromatic light of a specific wavelength band by passing an IR light source through a monochromatic optical filter, and a gas filter (reference cell) filled with a reference gas to be measured. ) And the measurement cell (Measurement cell) by alternating passage to measure the concentration of only the gas to be measured without interference by other gases.

In the existing air pollution measurement system using NDIR technology, an optical trigger is used outside each gas filter correlation (GFC) to distinguish the types of air pollutants.

However, it is very inefficient to install a plurality of optical triggers externally for each channel of the GFC, and process a lot of data in real time by classifying the types of air pollutants through the optical trigger.

The present invention has been made in view of the above, by using a single external light trigger and digital signal processing technology to distinguish the type of air pollutants and to analyze the concentration, to measure and analyze various types of pollutants It is an object of the present invention to provide an apparatus and method for measuring multi-pollutants using a non-dispersive infrared detector that can effectively process a large amount of data in real time.

In addition, the present invention uses the trigger signal and the threshold value through the optical coupler attached to the outer diameter of the gas correlation filter to distinguish the various pollutants by each measurement item, and sort the measured data in descending order and then the average value of the upper γ% data Another object of the present invention is to provide a multi-pollutant measuring device and method using a non-dispersion infrared detector that can determine the representative value of the pulse signal corresponding to the gas, and then calculate the concentration of the gas from the determined data.

The above object is a multi-contaminant measuring device using a non-dispersive infrared analysis method,

Infrared radiation; A gas correlation filter having a plurality of filter channels formed therethrough so that the reference cell and the measurement cell are alternately formed along the circumferential direction to simultaneously measure a plurality of pollutants; An absorption chamber having a sample gas in which various kinds of air pollutants are mixed and having multiple light paths formed by the gas correlation filter and a reflection mirror installed therein; And an infrared sensor for measuring infrared absorption energy of the filter channel, wherein an absorption difference between a reference cell signal of each measurement material and an output signal of the measurement cell is measured from the infrared absorption signal of each filter channel measured by the infrared sensor. It is achieved by a multi-contaminant measuring device using a non-dispersion infrared analysis method characterized in that to calculate the concentration of each measurement material by calculating the.

Preferably, the reference cell is filled with a reference gas to be measured, and a monochromatic optical filter having a unique wavelength band for each measurement item is installed in front of the reference cell and the measurement cell, and the infrared radiation is passed through the mono-optical filter. By making monochromatic light of a specific wavelength band and comparing the monochromatic light by passing the reference cell and the measurement cell alternately, the concentration of only the gas to be measured is detected.

In particular, the infrared radiation enters the absorption chamber through a rotating multi-gas correlation filter, the light passing through the measuring cell is absorbed corresponding to the concentration of the measurement gas contained in the sample in the absorption chamber, and passes through the reference cell One light is mostly absorbed by the high concentration reference gas to be measured, so that the degree of absorption in the absorption chamber in which the measurement gas is mixed with a lower concentration than the reference gas of the reference cell is ignored, and the infrared rays inputted through the infrared sensor From the absorption signal, the difference in absorbance between the reference cell signal for each measurement material and the output signal of the measurement cell is calculated to determine the concentration of each measurement material.

In addition, an optical trigger sensor is attached to the outside of the gas correlation filter to detect the synchronization signal of the rotating gas correlation filter.

On the other hand, the above object in the multi-contaminant measuring method using a non-dispersive infrared analysis method,

Measuring a sequential signal composed of various types of measurement item data through an infrared sensor; Classifying signals for each measurement item for various types of air pollutants; Determining the representative value of the pulse signal corresponding to the corresponding gas by obtaining the average value of the upper γ% data after sorting the measured data in descending order; And it is achieved by a multi-pollutant measurement method using a non-dispersive infrared analysis method characterized in that it comprises the step of calculating the concentration of the gas from the data determined in the step.

Preferably, when converting the analog signal measured by the multi-gas correlation filter and the infrared sensor into a digital signal to meet the data characteristics to be measured in order to obtain valid data from the reference cell and the measurement cell of the gas correlation filter for each measurement item Determining the sampling frequency and the rotation speed of the multi-gas correlation filter, the number of revolutions K per unit time of the gas correlation filter, the sampling frequency fs, and the number of digital data samples N _GFC obtained at the outputs of the respective reference and measurement cells, N _GFC = (D _C + 2D _S ) fs / (2πRK), where D _C is the aperture of the reference and measurement cells, D _S is the aperture of the infrared sensor, and R is the diameter of the reference and measurement cells. The distance from the center to the center of the gas correlation filter.

In addition, the step of separating the signal for each measurement item for the various types of air pollutants is synchronized to one cycle of the multi-gas correlation filter using a trigger signal and a threshold value through an optical coupler attached to the outer diameter of the gas correlation filter Finding; And counting the number of pulses using a threshold value based on the trigger signal to find a reference cell and a measurement cell signal of a corresponding measurement item.

에 의해 해당 가스의 농도를 계산하고, α는 비어 램버트 상수이고, L은 광 경로의 길이이고, V 및 V₀는 기준셀 및 측정셀의 출력전압이다.In addition, the step of calculating the concentration of the corresponding gas is the following equation

The concentration of the corresponding gas is calculated by using α, the Beer Lambert constant, L is the length of the optical path, and V and V ₀ are the output voltages of the reference cell and the measuring cell.

Accordingly, according to the apparatus and method for measuring multi-pollutants using a non-dispersion infrared detector according to the present invention, by using one external light trigger and digital signal processing technology, the types of air pollutants are classified and the concentration is analyzed. In measuring and analyzing kinds of pollutants, a large amount of data can be processed effectively in real time.

In addition, by presenting an algorithm for distinguishing the signals of various pollutants by the measured items using a single external synchronization signal, it is possible not only to measure various kinds of pollutants at the same time, but also the reliability of the measurement data. And accuracy can be secured.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a schematic diagram showing the configuration of an apparatus for measuring multiple pollutants using a non-dispersion infrared detector according to an embodiment of the present invention, and FIG. 2 is a signal processing flowchart for analyzing multiple pollutants.

The optical analysis system according to the present invention uses one external light trigger 12 and digital signal processing technology to classify the type of air pollutants and analyze the concentration. In measuring and analyzing various kinds of pollutants, digital signal processing technology is essential to effectively process a large amount of data in real time.

The present invention proposes a multi-pollutant measuring device using NDIR developed to simultaneously measure a variety of exhaust gas pollutants, and a microsignal detection method for analyzing the concentration of the multi-pollutant using the same.

The multi-pollutant measuring device includes a gas correlation filter 11 (gas correlation filter 11) having 12 filter channels 13 and an absorption chamber 14 having multiple light paths for simultaneously measuring up to six measurement substances. (Multi-path Optical Absorption chamber (MOA chamber)), and an infrared sensor 16 (in the following description, the NDIR detector is composed of an absorption chamber 14 and an infrared sensor 16).

In order to measure up to six measured substances at the same time, the GFC 11 has twelve filter channels 13 including a reference cell filled with a reference gas and a measurement cell for each measurement substance, and each filter item has a measurement item. A monochromatic optical filter with a unique wavelength band is attached.

Absorption chamber 14 has multiple light paths formed by multiple GFC 11 wheels and reflecting mirrors 15, and IR radiation 10 passes through multiple GFCs 11 that rotate through The sample gas mixed with air pollutants of the) enters the MOA chamber 14 is collected.

At this time, the light passing through the measurement cell is absorbed corresponding to the concentration of the measurement gas contained in the sample in the MOA chamber 14, and the light passing through the reference cell is mostly absorbed by the high concentration standard gas to be measured. The extent to which the measurement gas at a lower concentration relative to the gas is absorbed in the mixed MOA chamber 14 can be ignored.

Light emitted from the chamber 14 is measured by the infrared sensor 16 and the infrared absorption energy of each channel 13 is converted into a voltage which is an electrical signal. From the IR absorption signal of each channel 13, the difference in absorption between the reference cell signal for each measurement material and the output signal of the measurement cell is calculated to determine the concentration of each measurement material.

In this case, since the detector detects the light passing through the pair of reference cells and the measurement cells alternately, the detector output signal has a pulse shape modulated by the reference pulse and the measurement pulse.

On the other hand, the signal measured by the absorption chamber 14 and the infrared sensor 16 is an analog signal of a very low level and amplified using a pre-amplifier and then digitally converted by an analog to digital converter (ADC). Is converted into a signal.

The converted digital signal is a sequence composed of data of various kinds of measurement items. Data corresponding to each pollutant is separated using a signal processing detection algorithm.

In this case, an external optical trigger sensor (external optical trigger sensor) is used to detect the synchronization signal of the rotating multi-gas filter correlation wheel.

When converting the analog signal measured by the multiple GFC 11 wheel and the IR detector into a digital signal, the sampling frequency and the rotational speed of the multiple GFC 11 wheel are important variables for effective data collection.

First, assuming that the sampling frequency is fixed, as the rotational speed of the GFC wheel increases, the number of samples of the digital signal converted from the analog signal measured by the IR detector decreases.

The signal obtained from the reference cell for each measurement item and each gas filter corresponding to the measurement cell includes a power supply, an infrared sensor 16, a preprocessing amplifier, and a noise signal added during A / D conversion. Care must be taken in determining the sampling frequency to ensure to noise ratio and to effectively eliminate noise.

On the other hand, if the rotation speed of the multiple GFC 11 wheel is fixed, the number of data samples increases as the sampling frequency increases. However, the high sampling frequency includes unnecessary noise signals and increases the hardware cost for processing a large number of data.

Therefore, it is necessary to determine the sampling frequency and the rotational speed of the multiple GFC 11 wheels according to the data characteristics to be measured. 3 shows a design specification of multiple GFC 11 wheels. The number of revolutions per unit time of the GFC 11 wheel, the sampling frequency, and the number of digital data samples obtained at the output of each reference cell and the measurement cell N _GFC have the following correlation.

N _GFC = (D _C + 2D _S ) fs / (2πRK) (1)

here

N _GFC : Number of data samples digitally converted from the output of each reference cell and measurement cell [ea]

D _C : Aperture of reference and measuring cell [mm]

D _S : NDIR sensor diameter [mm]

fs: sampling frequency [Hz]

R: Distance from the center of reference and measurement cells to the center of the GFC 11 wheel

K: number of revolutions per unit time of multiple GFC (11) wheels [cycle / sec]

Equation (1) determines the operating characteristic parameters of the IR detector to efficiently perform data processing after analog signal detection and digital conversion.

In addition, the analog signal obtained through the absorption chamber 14 and the infrared sensor 16 is converted into a digital signal by the ADC. Zero gas consisting of nitrogen and 400 ppm of mixed gas (NO = 398 ppm, SO 2 = 392 ppm, CO = 402 ppm) are introduced into the absorption chamber 14 and the analog signal measured by the infrared sensor 16 is measured. The signal obtained by A / D conversion to fs = 1kHz is shown in FIGS. 4A and 4B.

As shown, each pulse signal is an output signal of a reference cell and a measurement cell for each measurement item, and two pulse signal pairs correspond to one measurement item. At this time, the base level of the pulse is contaminated by high frequency noise generated by the temperature characteristics of the NDIR detector and the rotation of various analog devices and devices, and shows drift characteristics by low frequency noise.

This base level is indicated as TH _base in FIG. 4. In order to analyze the measured data, it is necessary to accurately classify each measurement item and acquire valid data corresponding to the measurement item from the pulse signal.

First, accurate synchronization of one cycle of multiple GFC (11) wheels using a trigger value and threshold value through an optical coupler attached to the outer diameter of the GFC (11) to distinguish the signal corresponding to the metric. Find it.

The classification of measurement items from multiple signals consisting of continuous pulse signals is performed by counting the number of pulses using a threshold value TH _CNT based on a trigger signal to find reference cell and measurement cell signals of the corresponding measurement item.

As the high frequency noise added to the pulse signal amplitude may cause errors when counting the number of pulses using TH _CNT , which is a fixed threshold value in the cycle, the following method is used.

(2)

(2)

Where l is the parameter used to select an output value larger than the threshold without the influence of high frequency noise.

(3)

(3)

Here, CNT is a parameter for distinguishing a measurement cell or reference cell position.

At this time, when the concentration of SO ₂ to be measured is high, as shown in FIG. 4 (b), absorption of the IR light source is increased in the measurement cell, thereby reducing the amplitude of the output signal of the measurement cell. Therefore, the signal-to-noise ratio (SNR) is lowered, which makes it difficult to count the number of pulses.

In addition, the effect of high frequency noise added to the peak of the pulse signal should be considered when acquiring valid data from the corresponding pulse signal. 5 shows the peak shape according to the pulse amplitude magnitude when the GFC 11 wheel rotates at K = 1.135 [cycle / sec].

In order to obtain effective data from the peak of the pulse signal contaminated by the high frequency noise, the high frequency noise is removed by moving the upper data of the pulse based on TH _base .

(4)

(4)

Where k is an index of the external trigger 12 and γ is a constant depending on fs. avg _γ {sig (n)} is the average of the top γ% after sorting sig (n) in descending order.

In FIG. 5, the rising time and the falling time of the pulse are different according to the magnitude of the pulse amplitude, and accordingly, the flatness of the peak is also different. This peak difference can be estimated to be related to the aperture of the reference cell or measurement cell and the area (time) at which the infrared sensor 16 reacts.

The response speed of the infrared sensor 16 is very fast at 20 [nsec], but it is influenced by the charge / discharge time constant of the capacitor of the input stage of the preprocessing amplifier used to amplify the sensor output. If the measured voltage is large, the peak shape is similar to the Gaussian distribution.

Depending on the magnitude of such a signal, it is difficult to accurately measure the concentration from an output signal of a corresponding cell having a different peak shape. In order to solve this problem, it is necessary to lower the rotation speed of the multi-gas filter correlation wheel to increase the reaction time between the cell and the infrared sensor 16 to reduce the influence of the charge and discharge time to flatten the shape of the peak. 6 is a flow chart of an algorithm used for signal classification for each measurement item.

simulation

Computer simulations were performed to verify the performance of the proposed algorithm. The performance of the proposed signal detection algorithm was evaluated using the output signal of the NDIR multi-pollutant measurement system according to the present invention.

The standard mixed gas used in the performance evaluation is shown in Table 1, and the flow rate was maintained at 1000 [cc / min] using an orifice. When D _C = 10mm, D _S = 8mm, and R = 60mm, equation (1) becomes the following equation (3).

(5)

(5)

FIG. 7 shows N _GFC of the pulse signal measured for three different wheel rotation speeds (K _slow = 0.213, K _normal = 0.655, K _fast = 1.036) in equation (5). N _GFC theoretically calculated by Eq. (5) is about 224, 73 and 46 [samples] respectively, and the N _GFCs obtained from the measured signals are 225, 70 and 45 [samples] respectively, so the error for each rotational speed is within 5%. As can be seen that Equation (1) derived from the design specifications of the multiple GFC 11 wheels is valid.

8 shows the order of measurement items in the output signal of the NDIR detector, the external trigger signal, and the pulse signal measured for 20 sec. In Figure 8 (b) a = Smp.HCl, b = Ref.CO, c = Smp.CO, d = Ref.NO, e = Smp.NO, f = Ref.SO2, g = Smp.SO2, h = Ref.H2O, i = Smp.H2O, j = NONE, k = NONE, l = Ref.HCl.

The external trigger signal is a reference for distinguishing the position of the corresponding reference cell and the measurement cell in the measurement item in the manufactured multiple GFC (11) wheel. Therefore, in the detection algorithm that distinguishes the corresponding component signal from the multiple signals measured by the NDIR detector, accurate synchronization with the external trigger signal is very important for securing data reliability. In the multi-signal detection algorithm, the rotational speed K = 0.655 [cycle / sec] of the multiple GFC (11) wheels, the sampling frequency fs = 1 [kHz], and the higher data processing parameter γ = 15 are used to remove high frequency noise.

Table 2 shows the number of external trigger signals (TN) and gases detected using the proposed detection algorithm for CO, NO, and SO ₂ gases in the output signal (fs = 1 [kHz]) of FIG. 8 to confirm the multi-signal detection performance. Star N is _GFC .

In FIG. 8, the number of times the external trigger signal is changed from 5 [V] to 0 [V] is 14 times. The first synchronization signal is used for initialization, and the last synchronization signal is not complete because the number of pulses corresponding to one cycle is not perfect. Since it is not used, the external trigger signal detected by the algorithm for data processing is 12. From the results, it can be seen that the detection algorithm correctly detected synchronization with the trigger signal and each gas.

In FIG. 8 (a), the TH _base of the IR signal is 0 to 1 [V], and it can be seen that high frequency noise and low frequency noise are added. The difference between the theoretical value of Eq. By using a fixed threshold TH _base within one cycle of the GFC 11 wheel, it is caused by acquiring a signal value having a magnitude near the threshold.

However, since only the upper γ% of data is used to obtain the reference cell and the measured cell output values among the measured data in the detection algorithm of FIG. From these results, it can be seen that the gas species classification performance and data acquisition performance of the proposed detection algorithm are excellent.

9 and 10 show the reference cell and the measurement cell output values corresponding to CO, NO, and SO ₂ found by the change of the TH _base and the detection algorithm, respectively. Compared to the change of TH _base due to the low frequency drift noise of FIG. 9, the change of the output signal of the reference cell and the measuring cell of each gas is very small.

In addition, the NDIR multi-pollutant measurement system uses the ratio of two signals (measurement cell output signal / reference cell output signal) to determine the concentration, so the effect of low frequency noise can be ignored.

Therefore, in the multi-pollutant measuring system which simultaneously measures the multiple pollutants in the environmental air sample by non-dispersive infrared (NDIR) method in real time, the rotation speed and the speed of the wheel of the multi-gas correlation filter (GFC (11)) wheel for the development of the NDIR detector An algorithm for deriving the sampling frequency and the effective data acquisition method was proposed and the algorithm for the data detection of each measurement item from the continuous multi-pulse signal was proposed. Computer simulations were performed using data acquired from systems developed using actual GFC (11) wheels that were designed and fabricated to show the validity of equations that can theoretically predict acquired data. We confirmed the superior performance of the proposed detection algorithm for data acquisition by air pollutant.

While the invention has been shown and described with respect to certain preferred embodiments thereof, the invention is not limited to these embodiments, and has been claimed by those of ordinary skill in the art to which the invention pertains. It includes all the various forms of embodiments that can be carried out without departing from the spirit.

1 is a schematic diagram showing the configuration of a multi-pollutant measuring device using a non-dispersion infrared detector according to an embodiment of the present invention,

2 is a signal processing flowchart for analysis of multiple pollutants;

3 is a view showing a design specification of the multi-gas correlation filter in FIG.

4 is a graph illustrating an A / D converted infrared detector signal and a trigger signal;

5 is a graph showing the peak shape according to the output signal magnitude of the gas filter (reference cell, measurement cell),

6 is a flowchart illustrating a signal detection algorithm for measuring multi-pollutants according to an embodiment of the present invention.

7 is a graph showing N _GFC in the measured signal for each rotational speed of the gas correlation filter wheel,

8 is a graph illustrating a gas signal measured from an infrared detector signal, a trigger signal, and a pulse signal;

9 is a graph showing a change in TH _base due to low frequency drift noise;

10 is a graph showing a reference cell and a measurement cell output signal corresponding to CO, NO, and SO2.

<Description of the symbols for the main parts of the drawings>

10: IR radiation 11: Gas correlation filter

12: optical trigger 13: filter channel

14 absorption chamber 15 reflection mirror

16: infrared sensor

Claims (7)

In the apparatus for measuring multiple pollutants using non-dispersive infrared analysis, Infrared radiation; A gas correlation filter having a plurality of filter channels formed therethrough so that the reference cell and the measurement cell are alternately formed along the circumferential direction to simultaneously measure a plurality of pollutants; An absorption chamber having a sample gas in which various kinds of air pollutants are mixed, and having multiple light paths formed by the gas correlation filter and a reflection mirror installed therein; And And an infrared sensor for measuring infrared absorption energy of the filter channel, wherein the difference in absorbance between the reference cell signal for each measurement material and the output signal of the measurement cell is determined from the infrared absorption signal of each filter channel measured by the infrared sensor. Multi-contaminant measuring device using a non-dispersive infrared analysis method, characterized in that by calculating the concentration of each measurement material. The method according to claim 1, The reference cell is filled with a reference gas to be measured, and a monochromatic optical filter having a unique wavelength band for each measurement item is installed at the front of the reference cell and the measurement cell, and the infrared radiation is passed through the mono-bio optical filter in a specific wavelength band. By making a monochromatic light, and comparing the monochromatic light by passing the reference cell and the measuring cell alternately, the concentration of only the gas to be measured is detected. The method according to claim 2, The infrared radiation enters the absorption chamber through a rotating multi-gas correlation filter, and the light passing through the measurement cell absorbs the concentration corresponding to the measurement gas concentration contained in the sample in the absorption chamber, and the light passes through the reference cell. Is absorbed mostly by the high concentration reference gas to be measured, so that the degree of absorption in the absorption chamber in which the measurement gas of a lower concentration is mixed than the reference gas of the reference cell is ignored, and the infrared absorption signal input through the infrared sensor Device for measuring multi-contaminants using non-dispersion infrared analysis method to calculate the concentration of each measurement material by calculating the difference in absorbance between the reference cell signal for each measurement material and the output signal of the measurement cell. The method according to claim 3, Apparatus for measuring multiple pollutants using a non-dispersive infrared analysis method characterized in that the optical trigger sensor is attached to the outside of the gas correlation filter for detecting the synchronization signal of the rotating gas correlation filter. In the method for measuring multiple contaminants using non-dispersive infrared analysis, Measuring a sequential signal composed of data of various types of measurement items through a multi-gas correlation filter and an infrared sensor; Classifying signals for each measurement item for various types of air pollutants; Determining the representative value of the pulse signal corresponding to the corresponding gas by obtaining the average value of the upper γ% data after sorting the measured data in descending order; And Method for measuring a multi-pollutant using a non-dispersion infrared analysis method comprising the step of calculating the concentration of the gas from the data determined in the step. The method according to claim 5, When converting the analog signal measured by the multi-gas correlation filter and the infrared sensor into a digital signal, the sampling frequency and the multiplied sampling frequency corresponding to the data characteristics to be measured to obtain valid data from the reference cell and the measurement cell of the gas correlation filter for each measurement item determining the rotational speed of the gas correlation filter, and wherein the gas Any number of filters revolution per unit of K, the sampling frequency fs, and the digital site data Sam peulsu N _GFC is obtained at the output of each of the reference cell and the measuring cell is N _GFC = ( Has a correlation such as D _C + 2D _S ) fs / (2πRK), where D _C is the aperture of the reference and measurement cells, D _S is the aperture of the infrared sensor, and R is the gas correlation from the center of the reference and measurement cells. Method for measuring multiple pollutants using a non-dispersion infrared analysis, characterized in that the distance to the filter center. The method according to claim 5, Separating the signal for each measurement item for the various types of air pollutants is to find the synchronization for one cycle of the multi-gas correlation filter using the trigger signal and the threshold value through the optical coupler attached to the outer diameter of the gas correlation filter step; And Counting the number of pulses using a threshold value based on the trigger signal to find the reference cell and the measurement cell signal of the measurement item, multi-contaminant measurement method using a non-dispersive infrared analysis method.

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