JPH0656734U - Spectroscopic analyzer - Google Patents

Abstract

(57) [Summary] [Purpose] The continuous cooling time of the MCT detector, etc. is significantly extended to enable continuous measurement over an arbitrary time, and the cooling temperature of the MCT detector, etc. can be set almost arbitrarily. A spectroscopic analyzer that can be controlled is obtained. [Structure] A light beam emitted from a light source 1 can enter an interferometer 5, and a light beam emitted from an interferometer 5 enters a measurement cell 13 into which a measurement sample is introduced and is emitted from a measurement cell 13. The MCT detector is configured by a Stirling cooler 18 which is configured so that the luminous flux is incident on the MCT detector 17 and is controlled by the sequence controller 20.
17 is cooled.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a spectroscopic analyzer used for the purpose of measuring a measurement sample introduced from a chemical plant and controlling the chemical plant based on the measured data.

[0002]

[Prior art]

 As a spectroscopic analyzer used for controlling a chemical plant or the like, for example, the one shown in FIG. 2 is known. In FIG. 2, 31 is a light source, 32 is an ellipsoidal condensing mirror, 33 is a reflecting mirror, and 34 is a parabolic mirror, and the light reflected by this is incident on the interferometer 35. This interferometer 35 includes a beam splitter 36 that separates the light beam incident on the parabolic mirror 34 into a reflected light beam and a transmitted light beam, movable mirrors 37a and 37b, fixed mirrors 38a and 38b, and movable mirrors 37a and 37b. It is composed of a rocking plate 39 which is provided upright and rocks them back and forth. Then, the reflected light beam and the transmitted light beam separated by the beam splitter 36 are sequentially reflected separately by the movable mirrors 37a, 37b and the fixed mirrors 38a, 38b, and re-incident on the beam splitter in the same optical path. It interferes. Reference numerals 40, 41 and 42 are reflectors for the light flux emitted from the interferometer 35, and the light flux reflected by these is incident on the measurement cell 43. A measurement sample is introduced into the measurement cell 43 from a controlled object such as a chemical plant and distributed.

The luminous flux emitted from the measuring cell 43 is reflected by the reflecting mirrors 44, 45 and the parabolic mirror 46 and is incident on the MCT detector 47. Since it is necessary to cool the MCT detector 47 to the liquid nitrogen temperature (77K) before use, the MCT detector 47 is provided with a liquid nitrogen container (not shown), and this container holds nitrogen. The time is generally about 8 hours. 49 is a CPU, 51 is a laser head, 52 is a laser reflecting mirror, and 53 is a laser detector. A diffraction grating spectrometer is used instead of the interferometer 35, and an InSb detector is used instead of the MCT detector 47.

[0004]

As described above, in the conventional spectroscopic analyzer, the light flux that has passed through the interferometer 35 is incident on the measurement cell 43 into which the measurement sample is introduced from the controlled object, and the light flux emitted from the light is emitted. The MCT detector 47 cooled by liquid nitrogen is incident on the detector for detection, and the holding time of the liquid nitrogen container is about 8 hours. Therefore, since the MCT detector 47 needs to be replenished with liquid nitrogen when it is used for about 8 hours, there is a problem that continuous measurement cannot be performed beyond the holding time of liquid nitrogen. Moreover, since the liquid nitrogen is held in the container for about 8 hours, the time during which the measurement is disabled due to the liquid nitrogen replenishment becomes considerably long, and there is a problem that the influence on the control of the chemical plant becomes large. . There is also a problem that it is difficult to control the cooling temperature of the MCT detector 47 to a temperature at which its maximum sensitivity is obtained.

The present invention solves the above-mentioned problems, and greatly lengthens the continuous cooling possible time of the MCT detector and the like to the arbitrary time as compared with the conventional liquid nitrogen. It is an object of the present invention to obtain a spectroscopic analyzer that enables continuous measurement over a period of time and can control the cooling temperature of an MCT detector or the like almost arbitrarily.

[0006]

[Means for Solving the Problems]

 In the spectroscopic analyzer of the present invention, the light flux emitted from the light source is incident on the measurement cell through the interferometer or the diffraction grating spectrophotometer, and the light flux emitted from the measurement cell is incident on the MCT detector or the InSb detector. In the spectroscopic analyzer described above, the MCT detector or the InSb detector is cooled by a Stirling cooler, and the Stirling cooler is controlled by a controller.

[0007]

[Action]

 In the spectroscopic analyzer of the present invention, the MCT detector or the InSb detector that detects the light flux is cooled by the Stirling cooler when the light flux that has passed through the measurement cell into which the measurement sample is introduced is incident from the control target. The Stirling cooler can be used until its life is exhausted, and the life is extremely long compared to the liquid nitrogen retention time in the conventional example, and continuous measurement of the required time is required. As a result, the influence on a chemical plant controlled by this spectroscopic analyzer and other control objects can be almost eliminated. In addition, the Stirling cooler can be arbitrarily controlled by a control device.For example, the operation and stop of the Stirling cooler and other conditions are controlled in accordance with the control cycle of a chemical plant or other control target. In addition, it is possible to control the cooling temperature of the detector almost arbitrarily.

[0008]

【Example】

 An embodiment of the spectroscopic analyzer of the present invention will be described with respect to the Fourier transform infrared analyzer (FTIR) shown in FIG. In FIG. 1, 1 is a light source, 2 is an ellipsoidal condensing mirror, 3 is a plane mirror, 4 is a parabolic mirror, 5 is an interferometer, and the light beam incident on the interferometer 5 is reflected by a beam splitter 6 as a light beam. The light beams are separated into transmitted light beams, and the respective light beams are sequentially reflected by the chevron-shaped movable mirrors 7a and 7b to be incident on the fixed plane mirrors 8a and 8b, and are reflected and re-incident on the beam splitter 6 through the same optical path. The movable mirrors 7a and 7b are erected on a rocking plate 9 whose central portion is pivotally supported and reciprocally rocks. When the rocking plate 9 rocks, the reflected light beam and the transmitted light beam are separated. Since the respective optical path lengths are different from each other, interference occurs between the reflected light flux and the transmitted light flux which are re-incident on and combined with the beam splitter 6.

The light beam emitted from the interferometer 5 is configured to be sequentially reflected by the reflecting mirrors 10, 11 and 12 and incident on the measurement cell 13, and the light beam emitted from the measurement cell 13 is reflected by the reflecting mirror 14. , 15 and is reflected by the parabolic mirror 16 and enters the MCT detector 17. Then, the measurement sample is introduced into the measurement cell 13 from the controlled object. A Stirling cooler 18 cools the MCT detector 17, which can cool the MCT detector 17 to a required low temperature. Reference numeral 19 is a CPU connected to the interferometer 5 and the Stirling cooler 18. The detection signal of the MCT detector 17 is input to the CPU 19, and the CPU 19 outputs the swing control of the swing plate 9 of the interferometer 5. Do with a signal. A sequence controller 20 is connected to the Stirling cooler 18 and the CPU 19. Reference numeral 21 is a laser head, 22 is a laser reflecting mirror disposed in each of the optical path of the light beam reflected by the parabolic mirror 4 and the optical path of the light beam emitted from the interferometer 5, and 23 is a laser detector.

The sequence controller 20 is input with various data relating to control of the spectroscopic analyzer such as the control cycle of a chemical plant or other control target and the cooling temperature of the MCT detector 17 input to the sequence controller 20. The sequence controller 20 inputs necessary signals to the CPU 19 based on the data, and also inputs signals to the Stirling cooler 18 for control. If the CPU 19 has a sufficient capacity, the CPU 19 can also serve as the sequence controller 20.

In this spectroscopic analyzer, the sequence controller 20 inputs a signal to the Stirling cooler 18 in advance in response to the control cycle of the control target to start cooling the MCT detector 17, and when the measurement is started, Make sure the MCT detector 17 is cooled to the desired low temperature. On the other hand, when the measurement is started, the measurement sample is introduced from the controlled object into the measurement cell 13, and the CPU 19 outputs a signal in response to the output command of the sequence controller 20 to cause the oscillating plate 9 of the interferometer 5 to swing, 1 emits a luminous flux. Then, the light flux emitted from the light source 1 is condensed and reflected by the elliptical condenser mirror 2, and the light flux is reflected by the plane mirror 3 and the parabolic mirror 4 and enters the interferometer 5.

The light beam incident on the interferometer 5 is separated into a reflected light beam and a transmitted light beam by the beam splitter 6, and is reflected by the movable mirrors 7a, 7b and the fixed plane mirrors 8a, 8b, and then re-incident on the beam splitter 6. Then, they are combined and emitted from the interferometer 5. The luminous flux emitted from the interferometer 5 is sequentially reflected by the reflecting mirrors 10, 11, 12 and enters the measurement cell 13, and the measurement sample introduced into the measurement cell 13 from the controlled object is transmitted to the measurement cell. Ejected from 13. The luminous flux emitted from the measuring cell 13 is sequentially reflected by the reflecting mirrors 14 and 15 and the parabolic mirror 16 and is incident on the MCT detector 17, so that the MCT detector 17 detects the luminous flux and outputs a signal. Input to CPU19. A sequence controller 20 controls a control target such as a chemical plant based on a detection signal input to the CPU 19 by the MCT detector 17.

As described above, the MCT detector 17 can be cooled by the Stirling cooler 18, and the Stirling cooler 18 can be arbitrarily controlled by the sequence controller 20. Therefore, the MCT detector 17 can be cooled to a temperature at which the maximum sensitivity can be obtained, the light flux incident on the MCT detector 17 can be detected with high sensitivity, and the control cycle of the control target Accordingly, it is possible to operate the Stirling cooler 18 in advance to cool the MCT detector 17, etc., and it is possible to efficiently start the measurement of the sample without wasting time. Since there is no particular time constraint for continuous operation of the Stirling cooler 18, continuous measurement can be performed corresponding to the control cycle of the controlled object, and the life is considerably long. The time that cannot be measured due to the Stirling cooler 18 can be greatly shortened, and the influence on the control of the controlled object can be almost eliminated.

As described above, the MCT detector 17 can be cooled by operating the Stirling cooler 18 corresponding to the control cycle of the controlled object, and the temperature control of the MCT detector 17 at the time of interrupting the measurement can be efficiently performed. Therefore, it is possible to operate the Stirling cooler 18 efficiently, extend its life, and control the MCT detector 17 to a low temperature that allows efficient measurement. The same applies when a diffraction grating spectrometer is used instead of the interferometer 5 and an InSb detector is used instead of the MCT detector 17.

[0015]

[Effect of device]

 As described above, the spectroscopic analyzer according to the present invention cools the MCT detector or the InSb detector that detects the light flux passing through the measurement cell by the Stirling cooler, and controls the Stirling cooler by the control device. is there. This Stirling cooler has no particular time constraints on its operation and can continuously measure the required time, so it is possible to continue measuring the sample according to the control cycle of the controlled object. , It is possible to greatly reduce the time during which sample measurement becomes impossible due to the Stirling cooler. Since the Stirling cooler is controlled by the controller, it is possible to cool the MCT detector or the InSb detector to a temperature at which the maximum sensitivity can be obtained, and the incident light flux can be detected with high sensitivity. , It is possible to control the controlled object with high accuracy. It is also easy to operate the Stirling cooler intermittently in response to various conditions such as the control cycle to be controlled, so it is possible to operate the Stirling cooler efficiently and extend its life. Is.

[Brief description of drawings]

FIG. 1 is a block diagram of an embodiment of the present invention.

FIG. 2 is a configuration diagram of a conventional example.

[Explanation of symbols]

1: Light source, 5: Interferometer, 13: Measuring cell, 17: MCT detector, 18: Stirling cooler, 19: CPU, 20: Sequence controller.

Claims (1)

[Scope of utility model registration request] 1. A spectroscopic analysis in which a light beam emitted from a light source is incident on a measurement cell through an interferometer or a diffraction grating spectrometer, and a light beam emitted from this measurement cell is incident on an MCT detector or an InSb detector. In the apparatus, the MCT detector or the InSb detector is cooled by a Stirling cooler, and the Stirling cooler is controlled by a control device.