JPH0561585B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a first and a second component (for example, CH ₄ and Regarding the concentration of the _third component (total HC concentration, or
While the total NO concentration) and the individual concentration of the first component (CH ₄ concentration or NO concentration) are directly measured using the same type of detector (HC detector or NO detector), the difference between these two concentrations is from the second
Single concentration of component (non-methane HC concentration, or
This article relates to a fluid analyzer for simultaneous and continuous measurement of the three components, which is configured to be able to measure the concentrations of the three components simultaneously and continuously by using the so-called differential method that indirectly measures the NO ₂ concentration. teeth,
By applying a unique method called multi-fluid modulation method (this is the name given by the inventors) to this fluid analyzer for simultaneous and continuous measurement of three components, This was done with the aim of providing a completely new fluid analysis device that can simultaneously and continuously analyze these three components while using only one detector.

[Conventional technology]

For example, when performing fluid analysis to analyze the concentration (and thus the amount) of harmful components (particularly non-methane HC, NO ₂ , etc.) contained in the atmosphere, such as automobile exhaust gas, which is an example of a sample fluid, it is necessary to A fluid analyzer for simultaneous and continuous measurement of three components using a differential method is used, but in order to realize this with conventional fluid analyzers for simultaneous measurement of three components, it is necessary to increase the concentration of the third component (total Two detectors (sensors) were required, one for detecting the concentration of the first component alone and the other for detecting the concentration of the first component alone.

That is, when continuously measuring non-methane HC (second component), which is a particularly harmful component among the HC components in the sample fluid, as shown in Figure 7A,
Dividing the sample fluid S into two channels as a first sample fluid S1 and a second sample fluid S2,
A converter C consisting of a catalyst device, etc. is installed in one flow path to burn and remove only the non-methane HC (second component) in the first sample fluid S1, thereby converting the non-methane HC (second component). a first HC detector D for independently measuring the concentration of CH ₄ (first component) in the first sample fluid S1;
1 (for example, a flame ion detector: FID), and the other flow path is not provided with a converter as described above, and the total HC concentration in the second sample fluid S (the first A second analysis section A2 having a second HC detector D2 (also a flame ion detector: FID) for measuring the concentration of the third component as the sum of the second component and the second component is provided. Analyzers A1 and A2 and HC detectors D1 and D2 are required. Note that the independent concentration of non-methane HC as the second component is determined from the third component concentration (total HC concentration) obtained by the second signal processing circuit B2 connected to the second HC detector D1 of the second analysis section A2. , the first component alone concentration (CH ₄ concentration) obtained by the first signal processing circuit B1 connected to the first HC detector D1 of the first analysis section A1 can be obtained as an output from a subtraction circuit G that performs a subtraction process. can.

In addition, when continuously measuring NO ₂ (second component), which is a particularly harmful component of _NO The flow is divided into a first sample fluid S1 and a second sample fluid S2, and NO ₂ (second component) in the first sample fluid S1 is supplied to one flow path.
By installing a converter C consisting of a catalyst device, etc. for converting (reducing) into NO (first component), the total ON concentration (the first component) in the first sample fluid S1 subjected to the conversion process is a first NO detector D1 (e.g. a chemical luminescence detector: CLD) for measuring the concentration of the third component as the sum of the component and the second component;
The analysis section A1 is provided, and the other flow path is not provided with a converter as described above, and the second sample fluid S is
A second analysis section A2 having a second NO detector D2 (also a chemical luminescence detector: CLD) for independently measuring the NO (first component) concentration in the sample is provided. A1,
A2 and NO detectors D1 and D2 are required.
In addition, the independent concentration of NO ₂ as the second component is:
The third signal obtained by the first signal processing circuit B1 connected to the first NO detector D1 of the first analysis section A1
From the component concentration (total NO concentration), the second NO detector connected to the second NO detector D2 of the second analysis section A2 is determined.
It can be obtained as an output from a subtraction circuit G that performs subtraction processing on the concentration of the first component alone (NO concentration) obtained by the signal processing circuit B2.

[Problem that the invention seeks to solve]

However, as mentioned above, the first component and the second component, which are similar components contained in the same sample fluid,
When performing simultaneous and continuous analysis of the three components, and the third component defined as the sum of both components, two detectors (sensat) and an analysis section must be used as in the conventional apparatus described above. This means that not only (a) the analyzer becomes larger and the manufacturing cost becomes higher, but also (b) adjustments such as zero and span adjustments are required for each of the two detectors, making the measurement difficult. (c) When each detector is not adjusted sufficiently and there is a zero adjustment error or sensitivity difference between the two detectors, or when the two detectors are Mutual interference often occurs between instruments, which causes various problems, including very large measurement errors.

Therefore, in order to avoid such problems, two components (the first component and the third component) in the same sample fluid are alternately measured using a fluid analysis device equipped with only one detector. It is also possible to use a so-called batch analysis method, but in that case, simultaneous and continuous measurements cannot be performed, so the measurement data becomes discontinuous, and the concentration measurement results of the first component and the third component cannot be measured simultaneously. Since there is a time difference between the result of measuring the concentration of the second component and the result of measuring the concentration of the second component, there is a drawback that the reliability of the result of measuring the concentration of the second component obtained by calculating the difference therebetween is greatly deteriorated. Therefore, adopting such a batch analysis method simply to save on the individuality of the detector may greatly sacrifice the original purpose of fluid analysis, and may not be a good idea. do not have.

The present invention has been made in view of the above-mentioned conventional circumstances, and its purpose is to provide a simple and inexpensive structure that uses only one detector, which is smaller than the conventional one, and yet to be able to detect The three components as mentioned above, simultaneously and continuously,
Moreover, it is an object of the present invention to develop an analyzer for simultaneous and continuous measurement of three components that can perform accurate analysis.

[Means for solving problems]

In order to achieve the above object, the present invention, as is clear from the basic conceptual diagrams (diagrams corresponding to the claims) shown in FIGS. and a second sample fluid S2, and the flow path of the first sample fluid S1 is configured to separate a second sample fluid S2 in the first sample fluid S1, as shown in FIG.
By interposing a converter C that removes the component or converts it into the first component as shown in FIG. The flow path of the second sample fluid S2 is a third component concentration (total concentration) measurement line or a first component single concentration measurement line without providing a converter as described above, and the converted first sample fluid S1 and the unconverted second sample fluid S2 are subjected to mutually different frequencies F1, R2 by comparison fluids R1, R2, respectively.
Fluid modulation means V1 and V2 for modulating the fluid at F2 (Hertz) are provided in both flow paths, and only one detector D capable of detecting both the concentration of the first component and the concentration of the third component is provided. and an analysis section A to which both sample fluids S1 and S2 fluid-modulated in both flow paths are simultaneously and continuously supplied, and an output signal O from the detector D in the analysis section A is provided. , by separating the sample fluids S1 and S2 into signal components O1 and O2 of modulation frequencies F1 and F2 (hertz) and rectifying and smoothing them, respectively, to determine the individual concentration of the first component and the third component. A signal processing means B is provided, which is configured to be able to measure each concentration (total concentration) separately, and to be able to measure the individual concentration of the second component from the difference between the two concentration measurement results. The present invention provides a fluid analysis device for simultaneous and continuous measurement of three components using a multi-fluid modulation method and a differential method.

[Effect]

The effects achieved by this characteristic configuration are as follows.

That is, in the fluid analyzer for simultaneous and continuous measurement of three components using the dosing method and multi-fluid modulation method according to the present invention, the sample fluid S is The first sample fluid S1 is divided into a first sample fluid S1 and a second sample fluid S2, and the first sample fluid S1 is subjected to a process of removing a second component therein or converting it into a first component by a converter C. In a fluid analyzer equipped with a basic configuration for simultaneous and continuous measurement of three components, the first sample fluid S is supplied to the analysis section A, while the second sample fluid S2 is supplied to the analysis section A as is.
and the second sample fluid S2, respectively, by suitable fluid modulating means V, which is constituted by, for example, a rotary valve, a three-way switching solenoid valve, a four-way switching solenoid valve, etc.
1 and V2 to modulate the fluids at mutually different frequencies F1 and F2 with reference fluids R1 and R2, respectively, and then simultaneously and continuously supply them to the analysis section A having only one detector D, First, from that single detector D, both sample fluids S
The individual measurement signal components (O1,
We have adopted a unique method (multi-fluid modulation method) that was completely unthinkable in the conventional wisdom of obtaining one measurement signal O (= O1 + O2) in which O2) is superimposed all at once. The output signal O from the detector D is processed by signal processing, which is constructed by appropriately combining a frequency separation means, a signal rectification/smoothing means, and a subtraction means, as schematically illustrated in FIG. 1A and B. By using means B,
By performing signal processing of separating the signal components O1 and O2 of each modulation frequency F1 and F2 for each of the sample fluids S1 and S2 and subjecting them to rectification and smoothing processing, respectively, each of the sample fluids S1 and S2 is
2, that is, the measurement results of the concentration of the first (3) component and the concentration of the third (1) component,
Furthermore, since the structure is configured to calculate the difference between the third component concentration (total concentration) obtained in this way and the first component alone concentration to obtain the measurement result of the second component alone concentration, the sample When performing simultaneous and continuous analysis of the first component and the second component, which are similar components contained in the fluid S, and the third component defined as the sum of these two components, only one analysis part A is required.
All you need to do is to install a sensor and a detector (sensor).
Therefore, compared to conventional fluid analyzers for simultaneous and continuous measurement of three components, which required two detectors, the entire device can be made smaller and simpler, and costs can be reduced. Adjustment can be performed easily and in a short time, and since there is no possibility of gero adjustment error, sensitivity difference, or mutual interference between the two detectors as in the conventional case, good measurement accuracy can always be ensured.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described based on the drawings (FIGS. 2 to 7).

2 to 4 show an HC concentration analyzer as an example of a fluid analyzer for simultaneous and continuous measurement of three components using the differential method and multi-fluid modulation method according to the first embodiment. This is used, for example, when analyzing the concentration of nonmethane HC (second component), which is a particularly harmful component among HC components contained in a sample fluid S such as the atmosphere, automobile exhaust, or factory exhaust. For this purpose, we directly measured the individual concentration of methane (CH ₄ ), which is the first component, and the concentration of the third component (total HC concentration), which is defined as the sum of both the first and second components. The configuration is such that the individual concentration of nonmethane HC, which is the second component, is indirectly measured from the difference in the concentration measurement results.

Now, as shown in the overall schematic diagram of FIG. 2, the sample fluid S is transferred to the first sample fluid S1.
and a second sample fluid S2, the first sample fluid S2 is configured to be divided into two flow paths, and the flow path of the first sample fluid S1 is divided into two flow paths.
By installing a converter C consisting of a catalyst device etc. to burn and remove non-methane HC, which is the second component in 1, it is possible to measure the independent concentration of methane (CH ₄ ), which is the first component. line, while the flow path of the second sample fluid S2 is
The line is configured to measure the third component concentration (total HC concentration) without providing a converter as described above.

A first sample fluid S1 converted by the converter C (that is, non-methane HC is removed and contains only methane as HC), and a second sample fluid S1 that is not converted.
2 (that is, the same as the original sample fluid S containing both non-methane HC and methane), both sample fluids S1 and S2 are converted into comparative fluids R1 and R2 ( Generally, zero gas is used), the frequencies F1 and F2 (hertz) differ from each other (in this example,
F1 = 1 Hz, F2 = 2 Hz) (that is, the sample fluid and the comparison fluid are passed alternately at a predetermined frequency), and each of the fluid-modulated sample fluids S1, S2 (R1, R2) to the analysis section A, which has only one detector D (sensor),
It is configured to supply simultaneously and continuously. In this case, as the detector D in the analysis section A, a type through which the sample fluid passes directly, such as a flame ion detector (FID) for HC detection, is generally used. Both sample fluids S1, S2 (R
1, R2) are supplied to the detector D in a mixed state.

Therefore, the signal O output from the detector D via the preamplifier 2 has individual measurement signal components (O1, O2) corresponding to both sample fluids S1 and S2, as schematically shown in the figure. are obtained as a single measurement signal (O=O1+O2) in which these are collectively superimposed.

Therefore, the output signal O from the detector D is converted into a signal formed by combining frequency separation means E, signal rectification means F, and subtraction means G, as conceptually illustrated in FIG. Processing means B
The signal components O1, O2 of each modulation frequency F1, F2 for each sample fluid S1, S2 are calculated using
By performing signal processing in which the sample fluids S1 and S2 are separated and subjected to rectification processing and smoothing processing, respectively, the analytical values for each of the sample fluids S1 and S2, that is, the single concentration of the first component (methane) and the concentration of the third component, are obtained. (Total HC concentration) measurement results can be obtained separately and directly, and
It is configured such that the individual concentration of the second component (non-methane HC) can be indirectly measured from the difference between the two concentration measurement results.

The specific circuit configuration of the signal processing means B is as shown in the block circuit diagram of FIG.

That is, the signal O output from the detector D via the preamplifier 2 is input to two
one signal processing chain includes a modulation frequency F for the sample fluid S1.
Band pass filter a1 for separating and extracting (passing) only the 1 (1 Hz) signal O1
and a sample fluid S1 at the subsequent stage.
Due to the synchronizing signal from the synchronizing signal generator 1a attached to the fluid modulating means V1 (signal representing the actual fluid modulating operation by the fluid modulating means V1: 1 Hz), there is a possibility that the band pass filter a1 alone is insufficient. At the same time, it is possible to perform even more accurate frequency separation by supplementing a certain frequency separation effect.
A synchronous detection rectifier b1 is provided for simultaneously rectifying the output signal O1 from the bandpass filter a1 so that the separated alternating current can be converted to direct current,
Furthermore, a low pass filter (LPF) as a smoothing element c1 for smoothing the output signal from the synchronous detection rectifier b1 and removing high frequency nozzles is provided at the subsequent stage, and the other signal processing series includes: Bandpass filter a2 for separating and extracting (passing) only the signal O2 of modulation frequency F2 (2 Hz) for sample fluid S2
and a sample fluid S2 at the subsequent stage.
Due to the synchronizing signal from the synchronizing signal generator 1b attached to the fluid modulating means V2 (signal representing the actual fluid modulating operation by the fluid modulating means V2: 2 Hz), there is a possibility that the band pass filter a2 alone is insufficient. At the same time, it is possible to perform even more accurate frequency separation by supplementing a certain frequency separation effect.
A synchronous detection rectifier b2 is provided for synchronously rectifying the output signal O2 from the bandpass filter a2 so that the separated alternating current can be converted to direct current,
Furthermore, a low pass filter (LPF) as a smoothing element c2 for smoothing the output signal from the detection rectifier b2 and removing high frequency noise is provided at a subsequent stage, and further a signal processing system regarding the sample fluid S1 is provided. The output signal from the smoothing element c1 in the - input, and the smoothing element c in the signal processing system regarding the sample fluid S2.
A subtracter G is provided as a subtracting means for inputting the output signal from 2+input. Therefore, the measurement result of the single concentration of methane, which is the first component, is output from the smoothing element c1, and the smoothing element c2
outputs the measurement result of the concentration of the third component (total HC concentration), and the subtracter G outputs the measurement result of the single concentration of nonmethane HC, which is the second component.

As the signal processing means B, a computer capable of performing numerical analysis processing such as Fourier analysis (corresponding to frequency separation processing), absolute value averaging processing (corresponding to rectification/smoothing processing), and subtraction processing is used. However, in the device of the present invention, in particular, As mentioned above, the bandpass filters a1 and a2 and the synchronous detection rectifier b
1 and b2 and smoothing elements c1 and c2 are connected in series, and two signal processing lines are provided in parallel, so compared to the above-mentioned means using a computer or lock-in amplifier, etc., it is very easy to use. Not only can it be configured easily and inexpensively, but also the frequency separation effect, which may not be sufficient with only the bandpass filters a1 and a2, can be supplemented by the synchronous detection rectifiers b1 and b2, allowing for even more accurate frequency separation. For example, this configuration provides significantly superior signal processing performance (S/
This method has the advantage of being able to obtain a high N ratio.

By the way, each of the fluid modulation means V1 (V2)
is sample fluid S1 (S2) and comparison fluid R1
(R2) can be switched alternately at a predetermined frequency, the configuration is arbitrary.
For example, it may be constructed with a rotary valve as shown in FIG. 4A, or it may be constructed with a four-way switching solenoid valve as shown in FIG. 4B. There is no problem even if it is constructed using a three-way switching solenoid valve.

FIGS. 5 and 6 show _NO
A concentration analyzer is shown. This is also used, for example, when analyzing the concentration of NO ₂ (second component), which is _a particularly harmful component among the NO Therefore, the concentration of the first component, NO, and the concentration of the first and second components are determined.
A configuration in which the concentration of a third component (total NO concentration) defined as the sum of both components is directly measured, and the individual concentration of NO ₂ , which is the second component, is indirectly measured from the difference between the two concentration measurement results. has been done.

In the case of this second embodiment device, as is clear from the overall schematic diagram of FIG _. In addition to using a catalytic device to convert (reduce) the first component to NO, an NO detector such as a chemical luminescence detector (CLD) is used as the detector D in the analysis section A. There is.

Therefore, in this case, the first sample fluid S1
The flow path of the second sample fluid S2 becomes a line for measuring the third component concentration (total NO concentration) in the first sample fluid S1, and the flow path of the second sample fluid S2 becomes a line for measuring the third component concentration (total NO concentration) in the first sample fluid S1.
This is a line for measuring the individual concentration of the component NO, and as is clear from the block circuit diagram of the signal processing means B shown in FIG. The measurement results of the three component concentrations (total NO concentration) are output,
Also, the smoothing element c2 of the system of the first sample fluid S1
The subtracter G outputs the measurement result of the single concentration of NO, which is the first component, and the subtractor G outputs the measurement result of the single concentration of NO ₂ , which is the second component.

The other configurations of this second embodiment are the same as those of the first embodiment, so
Members having the same functions are given the same reference numerals, and their descriptions will be omitted.

It goes without saying that the present invention is not limited to the two embodiments described above, but is also applicable to other types of three-component measurements such as CO _x (CO, CO ₂ , total OC).

〔Effect of the invention〕

As is clear from the detailed description above, according to the fluid analysis device for simultaneous and continuous measurement of three components using the differential method and multi-fluid modulation method according to the present invention,
The sample fluid is divided into a first sample fluid and a second sample fluid, and the first sample fluid is processed to remove a second component therein or convert it into the first component using a converter. The first sample fluid and the second sample fluid are supplied to the analysis section, while the second sample fluid is supplied directly to the analysis section. The fluids are first modulated at different frequencies by the comparison fluid using fluid modulation means and then simultaneously and continuously supplied to the analysis section having only one detector. A unique multi-fluid modulation method is applied in which a single measurement signal in which individual measurement signal components corresponding to both sample fluids are collectively superimposed is obtained from a single detector. By using a signal processing means configured by appropriately combining a frequency separation means, a signal rectification/smoothing means, and a subtraction means, the output signal from the device is processed.
By performing signal processing of separating the signal components of each modulation frequency for each of the sample fluids and rectifying and smoothing each signal component, the analysis value for each of the sample fluids, that is, the concentration of the first (3) component, can be obtained. and the measurement result of the third (1) component concentration, and further calculates the difference between the third component concentration (total concentration) obtained in this way and the first component alone concentration, and calculates the difference of the second component concentration. By configuring it to obtain the measurement result of a single concentration, it can be configured very simply and inexpensively by providing only one analysis section and detector (sensor), but it can also be used to measure the same concentration contained in the sample fluid. The first component and the second component
It is now possible to perform simultaneous and continuous analysis of both components and a third component, which is defined as the sum of both components. Compared to a fluid analysis device, the entire device can be made smaller, simpler, and cost-reduced, and the detector can be adjusted easily and quickly, and it is possible to easily adjust the detectors between multiple detectors. Since zero adjustment errors, sensitivity differences, or mutual interference cannot occur, a remarkable effect is exhibited in that good measurement accuracy can always be ensured.

[Brief explanation of drawings]

Figures 1A and 1B show explanatory diagrams (diagrams corresponding to claims) of the basic concept of a fluid analyzer for simultaneous and continuous measurement of three components using the differential volume method and multi-fluid modulation method according to the present invention, respectively. . Further, FIGS. 2 to 6 show various specific embodiments of the device of the present invention,
2 is an overall schematic diagram of the first embodiment, FIG. 3 is a block circuit diagram of its signal processing means, FIGS. 4A and 4B are schematic illustrations of its fluid modulation means, and FIG. The figure is a general schematic diagram of the second embodiment, and FIG. 6 is a block circuit diagram of its signal processing means. FIGS. 7A and 7B are for explaining the technical background of the present invention and the problems of the prior art, and each shows an overall outline of a fluid analyzer for simultaneous and continuous measurement of three components according to the prior art. A configuration diagram is shown. S: sample fluid, S1: first sample fluid,
S2: second sample fluid, R1, R2: comparison fluid, F1, F2: modulation frequency, V1, V2: fluid modulation means, A: analysis section, D: detector, B: signal processing means, C: converter, O : Output signal from detector D, O1, O2: Each sample fluid S1, S
2, the signal components of each modulation frequency F1, F2.

Claims (1)

[Scope of Claims] 1 Regarding the first component and the second component, which are similar components contained in the sample fluid, and the third component defined as the sum of these two components, the concentration of the third component (total concentration ) and the individual concentration of the first component are directly measured by the same type of detector, while
A three-component simultaneous and continuous measurement solution configured to be able to simultaneously measure the concentrations of the three components by using a so-called differential method in which the single concentration of the second component is indirectly measured from the difference between the two concentrations. The analyzer is configured to divide the sample fluid into two channels as a first sample fluid and a second sample fluid, and the channel for the first sample fluid is configured to separate the second component in the first sample fluid. or the first
A line for measuring the concentration of the first component alone or a line for measuring the concentration of the third component (total concentration) is provided by interposing a converter for converting the fluid into components, and the flow path for the second sample fluid is provided with the converter as described above. the first component concentration (total concentration) measurement line or the first component individual concentration measurement line, and the converted first sample fluid and the unconverted second sample fluid are respectively controlled at different frequencies by the comparison fluid. Fluid modulation means for modulating the fluid is provided in both the flow paths, and has only one detector capable of detecting both the concentration of the first component and the concentration of the third component, and An analysis section is provided to which both fluid-modulated sample fluids are simultaneously and continuously supplied, and the output signal from the detector in the analysis section is separated into signal components of variable frequencies for each of the sample fluids. By performing rectification and smoothing treatment, the individual concentration of the first component and the third component are
A signal processing means is provided which is configured to be able to measure the concentration of each component (total concentration) separately, and to be able to measure the individual concentration of the second component from the difference between the two concentration measurement results. Fluid analysis device for simultaneous and continuous measurement of three components using the characteristic difference method and multi-fluid modulation method.