JP2009128175A - Near-infrared analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize a near-infrared analyzer with a simplified and miniaturized measurement system by providing a flow measurement function in a flow cell.
In a near-infrared analyzer for analyzing a sample by making light incident on an optical window provided in a flow cell in which the sample is distributed and analyzing the spectrum of transmitted light, a flow cell for circulating the sample; A heating unit; a light source unit that causes the light to enter the flow cell; and a signal processing / control unit that analyzes the sample by analyzing the transmitted light from the flow cell and controls the heating unit. By detecting the temperature change of the sample from the change in the center wavelength, by measuring the flow rate of the sample flowing in the flow cell according to the time from the start of heating of the heating unit until the sample reaches the optical window, A flow measurement function was provided in the flow cell so that a near-infrared analyzer with a simplified and miniaturized measurement system could be realized.
[Selection] Figure 1

Description

  The present invention relates to a near-infrared analyzer for a liquid sample.

A configuration block diagram showing an example of a conventional near-infrared analyzer is shown in FIG.
FIG. 6 shows a converter 601 including a Fourier spectrometer, a photodetector, etc., a probe 602, a sampling means 603, a control means 604 such as a personal computer, a higher-level control means 605, an optical fiber 606, It is constituted by a sample input port 607 in another channel.
The near-infrared analyzer 608 includes a converter 601, a probe 602, a sampling unit 603, an optical fiber 606, and a sample input port 607 in another channel.

  The sample is supplied to the sampling unit 603 via the sample input port 607, and the output of the sampling unit 603 is supplied to the probe 602.

  Input / output light of the converter 601 enters and exits the optical fiber 606, and input / output light of the optical fiber 606 enters and exits the probe 602.

  The converter 601 is connected with a control signal from the sampling unit 603 and is connected to the control units 604 and 605. Further, a sample detection signal that detects that a sample that can be analyzed is flowing from the sampling means 603 is connected to the converter 601.

Next, the operation of the near-infrared analyzer of FIG. 6 will be described.
First, a sample detection signal indicating that a sample that can be analyzed is flowing from the sampling means 603 is monitored, and analysis is started when a sample that can be analyzed is flowing.

  Spectral data corresponding to the selected flow path is captured from the optical fiber 606 by a photodetector, an A / D converter, or the like. At this time, the flow path selection signal indicating which flow path is selected from the sampling means 603 is input to the converter 601.

Based on the flow path selection signal, the selected flow path is specified, a calibration curve corresponding to the component to be analyzed is obtained from the list, and a property value is calculated based on this calibration curve.
The list is created in advance by assigning a calibration curve corresponding to the flow path having the converter 601 and the property value to be analyzed.

  The obtained property value is converted into an output signal such as an analog signal or a communication signal and output to the control means 605 or the like.

  As a result, by using a list of calibration curves corresponding to the flow channels and analysis components created in advance, even if a multi-channel configuration is used, one component of one flow channel is calculated using one calibration curve. Processing time is shortened.

  The near-infrared analyzer of FIG. 6 can easily cope with a plurality of channels and a plurality of channels by assigning a calibration curve corresponding to the flow path and the property value to be analyzed to the converter 601 and creating a list in advance. become.

Next, a block diagram showing an example of a conventional near-infrared analyzer is shown in FIG.
In the near-infrared analyzer of FIG. 7, the flow path 701, the flow rate detection unit 703, the flow rate signal processing / control unit 704, the light source unit 705, the flow cell 707, the spectroscopic unit 709, and the signal processing / control unit 710. It consists of.

Next, the operation of the near-infrared analyzer of FIG. 7 will be described.
An instruction is sent from the flow rate signal processing / control unit 704 to the flow rate detection unit 703 to send the sample in the sample flow direction 702 of the flow channel 701, and when the sample should be detected. In 703, the liquid flow rate in the flow path 701 is detected. After detecting the liquid flow rate, the light from the light source unit 705 is incident on the flow cell 707 installed in the flow path by the first signal light transmission means 706, and the liquid sample flowing through the flow path 701 is transmitted. The transmitted light is split by the spectroscopic unit 709 by the second signal light transmission means 708, and spectrum analysis is performed by the signal processing / control unit 710.

  The near-infrared analyzer of FIG. 7 includes a flow rate measurement unit 703 that is a flow channel measurement cell and a flow cell 707 that is a near-infrared analysis cell in a flow channel 701 (pipe or the like) through which a liquid flows. Component analysis by measurement and near infrared analysis can be performed.

Japanese Patent Laid-Open No. 9-288055

  In order to perform flow rate measurement and component analysis by the near-infrared analysis method, two cells, a flow rate measurement cell and a near-infrared analysis cell, are required, and there is a problem that the configuration of the near-infrared analyzer increases.

  Accordingly, an object of the present invention is to provide a near-infrared analyzer with a simplified and miniaturized measurement system.

In order to achieve the above object, according to the present invention, as shown in claim 1, the sample is obtained by making light incident on an optical window provided in a flow cell in which the sample is circulated, and analyzing the spectrum of the transmitted light. In the near-infrared analyzer, the flow cell for circulating the sample, the heating unit disposed on the upstream side of the optical window, the light source unit for allowing the light to enter the flow cell, and the transmitted light from the flow cell And a signal processing / control unit that controls the heating unit and detects the temperature change of the sample from a change in the center wavelength of the spectrum, and from the start of heating of the heating unit The flow rate of the sample flowing in the flow cell is measured according to the time until the sample reaches the optical window.

Moreover, as shown in claim 2, in the near-infrared analysis light according to claim 1, the signal processing / control unit heats the sample in the flow cell by causing the heating unit to generate heat during driving. It is characterized by that.

According to a third aspect of the present invention, in the near-infrared analysis light according to the first aspect, the signal processing / control unit causes the heating unit to generate heat at regular intervals.

According to a fourth aspect of the present invention, in the near-infrared analysis light according to any one of the first to third aspects, the signal processing / control unit performs a moisture concentration analysis.

In order to achieve the above object, according to the present invention, as shown in claim 5, light is incident on an optical window provided in a flow cell in which a sample is circulated and spectrum analysis of transmitted light is performed. In the near-infrared analyzer for analyzing the sample by the above, a flow cell for circulating the sample, a first optical window arranged on the upstream side along the flow of the sample, and a second optical window arranged on the downstream side A heating unit arranged at an equal distance from the first optical window and the second optical window, a light source unit that makes the light incident on the first optical window and the second optical window, and And a signal processing / control unit for analyzing the sample and controlling the heating unit while analyzing the spectrum of the transmitted light from the first optical window and the second optical window, and transmitting from the first optical window. The spectrum of light and the transmitted light from the second optical window. Wherein the by the difference of the spectrum to measure the flow rate of the sample flowing in the flow cell.

Moreover, as shown in claim 6, in the near-infrared analysis light according to claim 5, the signal processing / control unit causes the heating unit to generate heat during the flow rate measurement, thereby the sample in the flow cell. Is characterized by being warmed.

According to a seventh aspect of the present invention, in the near-infrared analysis light according to the fifth or sixth aspect, the signal processing / control unit performs a moisture concentration analysis.

The effects obtained by the typical inventions among those disclosed in the present application will be described as follows.

  Since the near-infrared analyzer of the present invention does not require a flow rate measurement cell and a near-infrared analysis cell, respectively, the measurement system can be reduced in size and the cost can be reduced by simplifying the measurement system.

  Hereinafter, the near-infrared analyzer of the present invention will be described with reference to the drawings.

  FIG. 1 is a structural diagram showing an embodiment of the near-infrared analyzer of the present invention.

  As shown in FIG. 1, in a near-infrared analyzer, a pipe 1 through which a sample flows, a flow cell 11 through which the sample flows, a light source 3 that causes light to enter the flow cell 11, and incident-side optics provided in the flow cell 11 The heating unit 6, the spectroscopic unit 8 a, and the flow cell 11 that are close to the flow path in the flow cell 11 and the window 5 and the emission side optical window 10 and that are disposed on the upstream side of the incident side optical window 5 and the emission side optical window 10. And a signal processing / control unit 9 for controlling the heating unit 6 as well as analyzing the sample by spectrum analysis.

  FIG. 2 is an enlarged view of the flow cell 11 portion of the near-infrared analyzer of FIG.

  The operation of FIGS. 1 and 2 will be described.

  First, the signal processing / control unit 9 causes the heating unit 6 to generate heat at regular time intervals.

  Further, the signal processing / control unit 9 heats the sample in the flow cell 11 by causing the heating unit 6 to generate heat during driving.

  In the flow rate measurement, a command signal for measuring the flow rate is transmitted from the signal processing / control unit 9 to the spectroscopic unit 8a. When a command signal is transmitted to the spectroscopic unit 8a, the spectrum of a sample (hereinafter referred to as a liquid sample) that has not been heated by the heating unit 6 is measured.

  In the spectrum measurement, there are a case where a spectrum of a liquid sample not warmed by the heating unit 6 is measured and a case where a spectrum of a liquid sample warmed by the heating unit 6 is measured.

When measuring the spectrum of the liquid sample that has not been heated by the heating unit 6, the command signal is sent from the signal processing / control unit 9 to the spectroscopic unit 8a to flow the liquid sample in the pipe flow direction 2 and to the spectroscopic unit 8a. The light is incident on the incident side optical window 5 provided in the flow cell 11 from the light source 3 by the first signal light transmission means 4, thereby transmitting the liquid sample flowing through the flow path 13 of the flow cell 11, Spectrum analysis is performed by the spectroscope 8 a and the signal processing / control unit 9 on the transmitted light that is transmitted through the second signal light transmission unit 7 and is output from the output-side optical window 10.

On the other hand, when the spectrum of the liquid sample heated by the heating unit 6 is measured, a command signal for flowing the liquid sample through the pipe 1 in the sample flow path direction 2 and measuring the flow rate from the signal processing / control unit 9 to the spectroscopic unit 8a. Is transmitted, and when the heating unit 6 close to the flow cell 11 starts to generate heat, the thermal mark 12 starts to flow into the flow path 13 in the flow cell 11 and is provided from the light source 3 to the flow cell 11 by the first signal light transmission means 4. When the light is incident on the incident side optical window 5, the liquid sample is transmitted, and the light transmitted by the second signal light transmission means 7 is emitted from the emission side optical window 10, and the spectroscope 8 a and the signal are transmitted. The spectrum is analyzed by the processing / control unit 9.

The flow rate measurement will be described.

First, a command to measure the flow rate is transmitted from the signal processing / control unit 9 to the spectroscopic unit 8a. When transmitted to the spectroscopic unit 8a, the spectrum of the liquid sample not warmed by the heating unit 6 is measured.

Next, the difference between the specific absorption center wavelength of moisture and the absorption wavelength without temperature dependence is obtained from the measured spectral data, with the absorption wavelength without temperature dependence as a reference point. The obtained data is referred to as difference data 1.

  A command signal (hereinafter referred to as pulse driving) for warming the liquid sample is transmitted from the signal processing / control unit 9 to the heating unit 6.

  The heating unit 6 is pulse-driven by a command signal transmitted from the signal processing / control unit 9 and starts to warm the liquid sample. The warmed liquid sample starts to flow in the flow path 13 in the flow sensor 11 as the thermal mark 12. Here, the thermal mark 12 refers to the one representing the heat level of the flowing liquid sample.

And the spectrum measurement of a liquid sample is performed at equal intervals.
In addition, even when spectrum measurement is performed at equal intervals, the difference between the specific absorption center wavelength of moisture and the absorption wavelength without temperature dependency is obtained using the absorption wavelength without temperature dependency as a reference point. The obtained data is referred to as difference data 2.

At the same time, the difference data 1 and the difference data 2 are compared.

The difference data 1 and 2 show the same value until the thermal mark 12 reaches the incident side optical window 5 and the emission side optical window 10 provided in the flow cell 11.

Next, the thermal mark 12 flows from the heating unit 6 and reaches the incident side optical window 5 and the emission side optical window 10 of the flow cell 11.

When the thermal mark 12 reaches the incident side optical window 5 and the outgoing side optical window 10, the wavelength before the thermal mark 12 reaches the incident side optical window 5 and the outgoing side optical window 10 is shifted, and the thermal mark 12 is changed to the incident side optical window. It changes to the wavelength when reaching the window 5 and the exit side optical window 10.
That is, the spectrum when the thermal mark 12 reaches the incident side optical window 5 and the emission side optical window 10 is observed.

When the signal processing / control unit 9 receives this change in wavelength, the spectrum measurement ends.
That is, the spectrum is measured by the spectroscopic unit 8 a and the signal processing / control unit 9.

Even when a wavelength-shifted spectrum is observed, the difference between the specific absorption center wavelength of moisture and the absorption wavelength without temperature dependency is obtained using the absorption wavelength without temperature dependency as a reference point. The obtained difference data is referred to as difference data 3.

Further, the time when the difference data 1 was observed (hereinafter referred to as observation time 1) and the time when the difference data 2 was observed (hereinafter referred to as observation time 2) are obtained.
That is, the time from the start to the end of spectrum measurement is grasped.

The flow rate can be obtained from the observation times 1 and 2 and the distance from the heating unit 6 to the incident side optical window 5 and the emission side optical window 10.

That is, the temperature change of the sample is detected from the change in the center wavelength of the spectrum, and the sample flows through the flow cell 11 according to the time from the start of heating by the heating unit 6 until the sample reaches the incident side optical window 5 and the emission side optical window 10. Sample flow rate can be measured.

Therefore, the near-infrared analyzer in FIGS. 1 and 2 can perform spectral analysis and flow rate measurement.

  FIG. 3 shows an absorption peak spectrum 14 at normal time (when the flow path 13 is not warmed by the heating unit 6) and an absorption peak spectrum 15 when the heat mark 12 passes (when the flow path 13 is warmed by the heating part 6). It is a graph.

By knowing the center absorption frequency at each temperature from FIG. 3, the temperature can be measured.
That is, the temperature can be measured without using a thermometer.

In the near-infrared analyzer of the present invention, the flow rate measurement and the near-infrared spectroscopic component measurement can be performed without the flow path detection unit and the flow rate signal processing / control unit which are flow rate measurement cells.

That is, the flow cell 11 which is a near-infrared analysis cell is configured in the pipe 1 (pipe or the like) through which the liquid sample flows, and the flow cell 11 can measure the flow rate. Further, components of the near infrared spectroscopy can be measured by components other than the heating unit 6.

That is, the measurement system can be downsized as compared with the conventional case.

Further, by providing the heating unit 6 close to the pipe 1 in the flow cell 11 and removing the flow path detection unit and the flow rate signal processing / control unit which are flow rate measurement cells, the measurement system can be simplified. .

Furthermore, the cost can be reduced by downsizing the measurement system and simplifying the measurement system.

FIG. 4 is an enlarged view of the flow cell 11 portion showing an embodiment of the near-infrared analyzer of the present invention.
As shown in FIG. 4, the near-infrared analyzer has the same configuration as the near-infrared analyzer of FIG. 1 except for the flow cell 11 portion. FIG. 4 is an enlarged view of the flow cell 11 portion of FIG.

In FIG. 4, the flow cell 11 includes a first optical window disposed on the upstream side along the flow of the sample, a second optical window disposed on the downstream side, and the heating unit 6 adjacent to the flow cell 11. Composed.

Moreover, the heating part 6 is arrange | positioned in the middle which becomes equidistant from a 1st optical window and a 2nd optical window.

Further, the upstream incident side optical window 17 and the upstream exit side optical window 18 are defined as a first optical window.

The downstream incident side optical window 22 and the downstream exit side optical window 23 are defined as second optical windows.

The operation of FIG. 4 will be described.
When light is incident from the light source 3 by the upstream first signal light transmission means 16 and spectrum analysis is performed, a sample (hereinafter referred to as a liquid sample) is caused to flow through the pipe 1 in the sample flow path direction 2, and in the flow cell 11. It flows into the flow path 13. The input liquid sample is incident on the upstream incident side optical window 17 provided in the flow cell 11 from the light source 3 by the upstream first signal light transmission means 16, and the incident light enters the upstream emission side optical window 18. When it reaches, the wavelength of the sample changes. When the signal processing / control unit 9 detects that the wavelength has changed, the spectrum is analyzed by the spectroscopic unit 8a to analyze the spectrum and analyze the sample.

Similarly, when light is incident from the light source 3 by the downstream first signal light transmission means 21 and spectrum analysis is performed, the liquid sample is caused to flow through the pipe 1 in the sample flow direction 2 and into the flow path 13 in the flow cell 11. Washed away. When passing between the upstream entrance and exit side optical windows 17 and 18 and between the downstream entrance and exit side optical windows 22 and 23, the downstream first signal light transmission means 21 provided from the light source 3 to the flow cell 11. When light enters the downstream incident side optical window 22 and the incident light reaches the downstream exit side optical window 23, the wavelength of the sample changes. When the signal processing / control unit 9 detects that the wavelength has changed, the spectrum is analyzed by the spectroscopic unit 8a to analyze the spectrum and analyze the sample.

Next, a method for measuring the flow rate will be described.

The signal processing / control unit heats the heating unit during the flow rate measurement, so that the sample in the flow cell is warmed.

When there is no flow in the flow path 13 in the flow cell 11, the liquid sample put into the flow path 13 in the flow cell 11 stagnates in the flow path 13 in the flow cell 11. The temperatures between the incident side optical window 17 and the upstream emission side optical window 18 and between the downstream incident side optical window 22 and the downstream emission side optical window 23 are constant. That is, the temperature distribution is the highest immediately below the heating unit 6 as in the temperature distribution 20, and the temperature decreases as the distance from the heating unit 6 increases.

On the other hand, when there is a flow in the flow path 13 in the flow cell 11, the liquid sample introduced into the flow path 13 in the flow cell 11 is connected to the upstream incident side optical window 17 and the upstream emission side optical in the flow path 13 in the flow cell 11. The liquid sample is heated by the heating unit 6 through the space between the windows 18, and the heated liquid sample passes between the downstream incident side optical window 22 and the downstream exit side optical window 23, whereby the upstream exit side optical window 18. And the spectrum of the transmitted light from the downstream emission side optical window 23 is different.

That is, when there is a flow in the flow path 13 in the flow cell 11, the flow flows into the flow cell due to the difference between the spectrum of the transmitted light from the upstream emission side optical window 18 and the spectrum of the transmitted light from the downstream emission side optical window 23. The flow rate of the sample can be measured.

  Further, the temperature distribution is a temperature distribution 25 and is different from the temperature distribution 20.

In the near-infrared analyzer of FIG. 4, a flow cell 11 that is a near-infrared analysis cell is configured in a pipe 1 (pipe or the like) through which a liquid flows, and the flow cell 11 can measure a flow rate.
And the near-infrared analyzer of FIG. 4 can perform the component analysis by a near-infrared analysis method in components other than the heating part 6 of the flow cell 11. FIG.

FIG. 5 is a structural diagram showing an embodiment of the near-infrared analyzer of the present invention.
5 is the same as the configuration requirements of the near-infrared analyzer of FIG.

  FIG. 5 is different from FIG. 1 in that a filter having a water-specific absorption wavelength is used for the spectroscopic unit 8b, and that spectrum analysis of water concentration and flow rate measurement are performed.

  In other words, it is a near-infrared analyzer specializing in spectral analysis of moisture concentration and flow measurement only of moisture.

Further, the near-infrared analyzer of the present invention can perform flow rate measurement and near-infrared spectroscopic component measurement without the flow path detection unit and the flow rate signal processing / control unit which are flow rate measurement cells.

That is, as in the near-infrared analyzer of FIG. 1, a flow cell 11 that is a near-infrared analysis cell is configured in a pipe 1 (pipe or the like) through which liquid flows, and the flow cell 11 performs flow rate measurement and near-infrared spectroscopy. Component analysis can be performed.

Therefore, it is possible to reduce the size of the measurement system as compared with the conventional case.

Further, by providing the heating unit 6 close to the pipe 1 in the flow cell 11 and removing the flow path detection unit and the flow rate signal processing / control unit which are flow rate measurement cells, the measurement system can be simplified. .

That is, the cost can be reduced by downsizing the measurement system and simplifying the measurement system.

Furthermore, the near-infrared analyzer of FIG. 5 is specialized in analyzing the wavelength of water only, and thus the spectroscopic unit 8a of FIG. 1 equipped with a filter capable of analyzing various types of wavelengths. Comparing with the spectroscopic unit 8b of FIG. 5 equipped with a dedicated filter for analyzing a specific wavelength, the spectroscopic unit 8b of FIG.

Further, the flow rate measurement method can measure the flow rate by either of the methods of the first embodiment and the second embodiment.

In addition, Example 1 and Example 2 differ in the flow measuring method. In Example 1, the flow rate is measured by managing the time, whereas in Example 2, the flow rate is measured by managing the temperature distribution.

Examples 1 and 2 and Example 3 differ in the object of analysis and the type of analysis. In the first and second embodiments, various types of wavelengths are analyzed, whereas in the third embodiment, concentration analysis is performed for a specific wavelength.

FIG. 1 is a structural diagram showing an embodiment of the present invention. FIG. 2 is an enlarged view of the flow cell portion of FIG. 1 showing an embodiment of the present invention. FIG. 3 is a graph showing the temperature influence on the near-infrared absorption spectrum of FIG. 1 showing one embodiment of the present invention. FIG. 4 is an enlarged view of a flow cell portion showing another embodiment of the present invention. FIG. 5 is a block diagram showing a conventional example. FIG. 6 is a block diagram showing a conventional embodiment. FIG. 7 is a block diagram showing a conventional example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Pipe 2 Sample flow direction 3 Light source 4 1st signal light transmission means 5 Incident side optical window 6 Heating part 7 2nd signal light transmission means 8a Spectroscopic part 8b Spectroscopic part 9 Signal processing / control part 10 Output side optical window 11 Flow cell 12 Thermal mark 13 Flow path 14 Absorption peak spectrum at normal time 15 Absorption peak spectrum at passage of thermal mark 16 Upstream first signal light transmission means 17 Upstream incident side optical window 18 Upstream emission side optical window 19 Upstream second signal light transmission means 20 Temperature distribution (no flow)
21 downstream first signal light transmission means 22 downstream incident side optical window 23 downstream emission side optical window 24 downstream second signal light transmission means 25 temperature distribution (with flow)
601 Converter 602 Probe 603 Sampling means 604 Control means 605 Control means 606 Optical fiber 607 Sample input port 608 of other flow path Near infrared analyzer 701 Flow path 702 Sample flow rate direction 703 Flow rate detection section 704 Flow rate signal processing / control section 705 Light source unit 706 First signal light transmission unit 707 Flow cell 708 Second signal light transmission unit 709 Spectroscopic unit 710 Signal processing / control unit

Claims (7)

In a near-infrared analyzer for analyzing a sample by making light incident on an optical window provided in a flow cell in which the sample is distributed and analyzing the transmitted light spectrum,
A flow cell for circulating the sample;
A heating unit disposed upstream of the optical window;
A light source unit for causing the light to enter the flow cell;
A signal processing / control unit for analyzing the sample by analyzing the spectrum of the transmitted light from the flow cell and controlling the heating unit;
Detect the temperature change of the sample from the change in the center wavelength of the spectrum,
The near-infrared analyzer, wherein the flow rate of the sample flowing in the flow cell is measured according to the time from the start of heating by the heating unit until the sample reaches the optical window. The near-infrared analyzer according to claim 1, wherein the signal processing / control unit heats the sample in the flow cell by causing the heating unit to generate heat during driving. The near-infrared analyzer according to claim 1 or 2, wherein the signal processing / control unit causes the heating unit to generate heat at regular intervals.   The near-infrared analyzer according to claim 1, wherein the signal processing / control unit performs a moisture concentration analysis. In a near-infrared analyzer for analyzing a sample by making light incident on an optical window provided in a flow cell in which the sample is distributed and analyzing the transmitted light spectrum,
A flow cell for circulating the sample;
A first optical window disposed upstream along the flow of the sample and a second optical window disposed downstream;
A heating unit disposed at an intermediate distance from the first optical window and the second optical window; and
A light source unit for causing the light to enter the first optical window and the second optical window;
A signal processing / control unit for analyzing the sample by spectrally analyzing the transmitted light from the first optical window and the second optical window and controlling the heating unit;
Near-infrared analysis characterized in that the flow rate of the sample flowing in the flow cell is measured by the difference between the spectrum of the transmitted light from the first optical window and the spectrum of the transmitted light from the second optical window. Total.   6. The near-infrared analyzer according to claim 5, wherein the signal processing / control unit heats the sample in the flow cell by causing the heating unit to generate heat during flow rate measurement.   The near-infrared analyzer according to claim 5 or 6, wherein the signal processing / control unit performs a moisture concentration analysis.

Images