JPH05215683A - Infrared gas analyzer - Google Patents

Abstract

PURPOSE:To obtain an infrared gas analyzer constituted so that a plurality of infrared sensors are arranged with respect to a measuring cell having a small caliber with allowance in a dispersed state and a gas filter is easily arranged in combination with the specific sensor. CONSTITUTION:In an absorbancy type infrared gas analyzer wherein an infrared ray source 2 is arranged on the incident side of a measuring cell 1 filled with sample gas and a plurality of infrared sensors 2 corresponding to the component gases to be measured in the sample gas and a plurality of band-pass filters 7 are provided on the emitting side of the cell 1, a light distributing cell 9 equipped with a reflecting mirror 9d dividing the beam transmitted through the measuring cell 1 into two directions is arranged behind the emitting surface of the measuring cell 1. A plurality of the infrared sensors 6 and gas filters 10 are arranged to the emitting edges in two directions of the light distributing cell in a distributed state to measure and analyze various component gases in the sample gas.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an absorption type infrared gas analyzer for performing qualitative and quantitative analysis of various measurement component gases contained in a sample gas.

[0002]

2. Description of the Related Art The absorption type infrared gas analyzer mentioned above is
Qualitative and quantitative analysis of the sample gas is performed from the amount of infrared absorption by the measurement component gas contained in the sample gas. This method generally has good selectivity and high measurement sensitivity, so it is used in various fields as a gas analyzer. Widely used.

Next, the structure of a conventional single-beam type absorption type infrared gas analyzer and its operating principle will be described with reference to FIG. In the figure, 1 is a measuring cell through which a sample gas flows, 2 is an infrared light source provided on the incident side of the measuring cell 1, 3 is a rotary chopper that intermittently interrupts the luminous flux emitted from the infrared light source 2, and 4 is the emitting side of the measuring cell 1. In the sensor mounting block 5, a plurality of infrared sensors 6 corresponding to various measurement component gases contained in the sample gas (three represented by # 1 to # 3 in the illustrated example) are band-pass filters. (Multilayer interference filter for imparting wavelength selectivity to the infrared sensor) 7 is arranged side by side. A solid-state sensor such as a pyroelectric sensor or a semiconductor sensor is used as the infrared sensor 6.

With this structure, the infrared light emitted from the light source 2 is contained in the sample gas in the process of entering the measurement cell 1 as a light beam 8 which is intermittently cut by the chopper 3 at a constant period and is transmitted through the measurement cell 1. Infrared wavelengths peculiar to various measurement component gases are absorbed according to the concentration of the components. Further, the light flux that has passed through the measurement cell 1 is received by each infrared sensor 6 through the bandpass filter 7, and the detection signal corresponding to the amount of the light is converted into an electric signal and taken out to the outside.

[0005]

By the way, as described above, in order to simultaneously analyze a plurality of measurement component gases contained in the sample gas, a plurality of infrared sensors 6 are attached to the sensor mounting block 5 of the detector 4 in a band. In the configuration in which the infrared filter is installed side by side in combination with the pass filter 7, the larger the number of installed infrared sensors, the larger the area occupied on the sensor mounting block 5, and accordingly the diameter of the measuring cell 1 is also increased accordingly. There must be. Moreover, as the diameter of the measuring cell 1 becomes larger, the volume of the sample gas to be filled in the cell increases due to the increase in the internal volume of the cell, and as a result, the residence time of the sample gas in the measuring cell becomes longer and stable. In addition to a long response time until a measurement output is obtained, a response characteristic is delayed, and further, a problem occurs that the light energy density received by the infrared sensor 6 is reduced and the S / N ratio is reduced. Therefore, it is desired that the diameter of the measuring cell 1 be as small as possible. However, if the diameter of the measuring cell is reduced with the conventional structure, the number of infrared sensors installed is naturally limited in accordance with the diameter.

Further, when a specific component gas and an interference component gas whose absorption wavelength bands partially overlap each other are mixed in the sample gas, as a means for suppressing the influence of the interference gas on the analysis result, A gas filter may be used in combination before the infrared sensor. Then, as in the conventional detection unit shown in FIG.
In a configuration in which the sensors are collectively and side-by-side arranged on the sensor mounting block 5, it is difficult to mount the gas filter individually only on a specific infrared sensor due to restrictions of the sensor arrangement and space. A gas filter with a special structure that is configured according to the array of infrared sensors is required.

The present invention has been made in view of the above points, and it is an object of the present invention to solve the above problems and to disperse a plurality of infrared sensors in a measurement cell having a small diameter with a sufficient arrangement. Infrared gas analyzer that can easily be used by combining a gas filter with various sensors,
In particular, it is to provide the configuration of the detection unit.

[0008]

In order to achieve the above object, in the gas analyzer of the present invention, a light distribution cell for separating the light flux transmitted through the measurement cell into two directions is provided behind the emission surface of the measurement cell. It is assumed that a plurality of infrared sensors are arranged so as to be distributed to each light emitting end face of the light distribution cell so as to face each other.

Further, the light distribution cell in the above structure is a triangular trapezoidal hollow block having an outer shape of a right-angled prism body, and one of two surfaces orthogonal to each other has a light entrance window facing the exit end surface of the measurement cell, and the other. The first light output window is opened on the surface of the above, and the reflection mirror having the second light output window perforated is arranged on the inclined surface at an angle of 45 °, or after replacing the reflection mirror in the above configuration with a half mirror, There is a configuration in which a second light emitting end face that transmits light in one direction is formed.

Further, if necessary, an infrared sensor can be installed in the light distribution cell having the above-mentioned structure by combining a gas filter behind the light emitting end face of the light distribution cell.

[0011]

According to the above construction, the light beam transmitted through the measuring cell is split into two directions by the light distribution cell, distributed to the respective light emitting end faces, and received by the infrared sensors distributed and arranged on the optical axes in the two directions. .. Therefore, the arrangement space of the infrared sensor is not limited by the aperture of the measurement cell and is sufficiently secured on the light emitting end face side of the light distribution cell, and even if the aperture of the measurement cell is small, a plurality of infrared sensors can be provided with a margin for the light distribution cell. It is possible to disperse and deploy on each light emitting end face. Also,
By attaching a gas filter to the light emitting end surface of the light distribution cell as needed, it is possible to easily use a gas filter in combination with a specific infrared sensor.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings of the embodiments, the same members corresponding to FIG. 4 are denoted by the same reference numerals. First, in FIGS. 1 and 2, a light distribution cell 9 for splitting a light beam transmitted through the measurement cell into two directions and a gas filter 10 are installed behind the exit end face side of the measurement cell 1. .. # 3, the three infrared sensors 6 are divided into two groups and distributed to each light emitting end face side of the light distribution cell 9 to configure the detection unit 4.

Here, as can be seen from the structural development view shown in FIG. 2, the light distribution cell 9 has a triangular trapezoidal hollow block whose outer shape is a right-angled prism body, and has one of two surfaces orthogonal to each other. A light entrance window 9a is opened toward the exit side end surface of the measurement cell 1, and a first light exit window 9b is opened on the other surface in a direction perpendicular to the light entrance window. A reflecting mirror 9d in which a second light output window 9c is perforated is fitted in the portion. Then, the light distribution cell 9 having the above configuration
On the other hand, as shown in FIG. 1, two infrared sensors (# 1, # 2) are provided behind the first light exit window 9b in combination with the bandpass filter 7, and the reflecting mirror 9d is perforated. An infrared sensor (# 3) is provided behind the second light exit window 9c via a gas filter 10.

With such a configuration, the infrared light flux 8 that has passed through the measurement cell 1 enters through the light entrance window 9a of the light distribution cell 9, and the light fluxes 8a and 8b schematically shown in FIG. After being reflected by 9d and deflected in a right angle direction, it passes through the first light exit window 9b and is received by the infrared sensors (# 1, # 2) arranged behind it. Further, the light beam 8c that passes through the central portion is the second light exit window 9c that is formed by boring in the reflecting mirror 9d.
After passing through, the infrared sensor (# 3) receives the light through the gas filter 10 arranged behind it. If necessary, a gas filter may be attached to the back of the first light exit window 9b as well.

Next, an application example of the above-mentioned optical distribution cell 9 is shown in FIG. In this embodiment, the reflecting mirror in FIG. 2 is replaced with a half mirror 9e, and a second light emitting end face is formed on the rear side of the half mirror 9e to form a beam splitter. With this configuration, the luminous fluxes 8a to 8c that have passed through the measurement cell 1
Is split into two directions by a half mirror 9e incorporated in the light distribution cell 9, one of which is deflected at a right angle toward the first light exit window 9b, and the other is reflected by the half mirror 9e.
Go straight through e.

In the configuration of FIG. 3 employing the half mirror 9e, the light exit end face in the straight traveling direction is limited to a narrow range of the second light exit window 9c formed in the reflecting mirror 9d as in the structure of FIG. Therefore, it is possible to arrange a plurality of infrared sensors side by side here.

[0017]

As described above, according to the configuration of the present invention, a light distribution cell for splitting transmitted light in two directions is provided behind the emission end face of the measurement cell, and a plurality of infrared sensors are provided in the light distribution cell. Since it is distributed and distributed to the light emitting end face side of the direction, the arrangement space of the infrared sensor can be sufficiently secured on the light emitting end face side of the light distribution cell without being restricted by the diameter of the measuring cell, and even for the measuring cell of a small diameter. It is possible to perform measurement and analysis of various component gases in the sample gas with a sufficient arrangement of a plurality of infrared sensors. Further, even when a gas filter is combined with a specific infrared sensor, there is an advantage that the gas filter can be easily attached to the light emitting end face side of the light distribution cell and used, if necessary.

[Brief description of drawings]

FIG. 1 is a sectional view of the configuration of an embodiment of the present invention.

FIG. 2 is a structural development view of the light distribution cell in FIG.

FIG. 3 is a configuration cross-sectional view of an application example of a light distribution cell.

FIG. 4 is a sectional view showing the configuration of a conventional infrared gas analyzer.

[Explanation of symbols]

 1 Measuring Cell 2 Infrared Light Source 4 Detecting Part 6 Infrared Sensor 7 Bandpass Filter 8 Luminous Flux 9 Light Distribution Cell 9a Input Window 9b First Light Output Window 9c Second Light Output Window 9d Reflector 9e Half Mirror 10 Gas Filter

Claims (4)

[Claims] 1. An absorption type infrared gas analyzer in which an infrared light source is installed on the incident side of a measurement cell filled with a sample gas and a plurality of infrared sensors corresponding to the respective measurement component gases in the sample gas are installed on the exit side. In the above, a light distribution cell that disperses the light flux transmitted through the measurement cell into two directions is arranged behind the emission surface of the measurement cell, and a plurality of infrared sensors are arranged facing each other at each light emitting end surface of the light distribution cell. Infrared gas analyzer characterized by. 2. The infrared gas analyzer according to claim 1, wherein the light distribution cell is a hollow block having an outer shape of a right-angled prism body, and one surface of the light distribution cell which is perpendicular to the light reception cell faces an emission end surface of the measurement cell. Infrared gas, characterized in that a first light exit window is opened on the other side of the window, and a reflecting mirror having a second light exit window is formed on the inclined surface at an angle of 45 °. Analyzer. 3. The infrared gas analyzer according to claim 1, wherein the light distribution cell is a hollow block having an outer shape of a right-angled prism body, and one of the surfaces intersecting with each other intersects the exit end surface of the measurement cell. The first light exit window is opened on the other side of the window, and a half mirror is arranged on the inclined surface at an angle of 45 °, and a second light exit end surface for transmitting light is formed behind the half mirror. Infrared gas analyzer. 4. The infrared gas analyzer according to claim 1, wherein an infrared sensor is disposed behind at least one light emitting end face of the light distribution cell via a gas filter.