JP2602854Y2 - Comparison optical analyzer - Google Patents

Description

[Detailed description of the invention]

[0001]

The present invention relates to a sample cell and a comparison cell (including an infrared ray and an ultraviolet ray) such as an infrared gas analyzer.
The present invention relates to a comparative optical analyzer for measuring the concentration of a specific substance contained in a gas or a liquid by comparing characteristics such as light transmittance of a substance (a gas or a liquid) in both cells by projecting the two.

[0002]

2. Description of the Related Art For example, when a nitrogen oxide concentration in a combustion gas is continuously measured, an infrared gas analyzer can be used. The configuration and operation of such an infrared gas analyzer will be described with reference to FIGS.

As shown in FIG. 2, this infrared gas analyzer has two cylindrical cells, a comparative cell 11 and a sample cell 12, arranged in parallel, and a light source for projecting infrared rays to both cells 11, 12. 14, a condenser 16 for condensing the infrared light that has passed through both cells 11 and 12, a detector 18 for selectively detecting the amount of infrared light absorbed by the gas to be measured, and a comparison cell for comparing the infrared light from the light source 14. 11 and a rotating sector 21 as a sector plate for selectively projecting onto any one of the sample cells 12. Of the two cells 11 and 12, a reference gas is sealed or circulated in the comparison cell 11, and a gas to be measured is flown in the sample cell 12. The rotating sector 21 is painted black to prevent diffuse reflection and stray light. As shown in FIG. 3, an opening 21a is provided on the outer peripheral side of the rotating sector 21 and an opening 21a is provided on the inner peripheral side thereof.
b is provided, and by rotating the rotating sector 21, infrared rays from the light source 14
And the sample cell 12 is projected alternately.

Assuming that the rotating sector 21 is at the position shown in FIG.
The infrared rays radiated from a are reflected directly by the reflecting mirror 14b whose inner surface is a paraboloid of revolution or directly,
The infrared rays directed toward the sample cell 12 but directed toward the sample cell 12 are blocked by the rotating sector 21, so that the infrared rays are projected only on the comparison cell 11. After passing through the reference gas in the cell, the infrared light projected to the comparison cell 11 is collected by the light collector 16 and the amount thereof is measured by the detector 18. Thus, the amount of infrared absorption by the reference gas in the comparison cell 11 is detected. Next, when the rotating sector 21 is rotated by 180 degrees, of the infrared rays from the light source 14 toward the two cells 11 and 12, the infrared rays toward the comparison cell 11 are blocked by the rotating sector 21, and the infrared rays are projected only to the sample cell 12. .
After the infrared light projected on the sample cell 12 passes through the gas to be measured in the cell, the infrared light is collected by the light collector 16 and the amount thereof is measured by the detector 18. Thereby, the sample cell 12
Detects the amount of infrared absorption by the gas to be measured inside.
By comparing the amount of absorption with the amount of absorption by the reference gas, the concentration of the specific substance contained in the gas to be measured can be obtained.

[0005]

In the above-mentioned infrared gas analyzer which is a kind of comparative optical analyzer, the rotating sector 21 is black by painting or the like in order to prevent irregular reflection and stray light as described above. For example, rotating sector 21
Is located at the position shown in FIG.
Are not used for measurement because infrared rays from the light source 14 other than those projected on the comparison cell 11 are absorbed by the rotating sector 21 and the like. For this reason, the use efficiency of the light source in the conventional comparative light analyzer was poor. That is, the emission surface of the light source 14 is connected to both cells 11 and 12.
Must be twice as large as the diameter of the end face of each cell so as to cover the end face of the cell. For this reason, FIG.
As schematically shown in (b), when infrared rays are projected onto one of the cells (for example, the comparison cell 11), the amount is only about 1/4 of the infrared rays emitted from the light source 14, and
The remaining about 3/4 is not used for measurement because it is absorbed by the rotating sector 21 and the like. In addition, since the infrared light absorbed by the rotating sector 21 becomes heat, and the rotating sector 21 is heated by the heat and becomes high temperature, the rotating sector 21 itself becomes a radiation source of the infrared light, thereby deteriorating the stability of measurement. was there.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a comparative optical analyzer in which the utilization efficiency of a light source is high and the temperature of a sector plate (rotating sector) does not increase. Is to do.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, in the comparative photoanalyzer according to the present invention, light from a single light source is supplied to a sample cell and a reference cell arranged in parallel, a light source, a sample cell and a reference cell. A light source comprising a reflector with a paraboloid of revolution for radiating vertically to a sector plate arranged between the cell and a light source element arranged at the focal position of the reflector with the paraboloid of revolution. When the sector plate is at the first position, the light from the light source to the sample cell is blocked to project light from the light source to the comparison cell, and when the sector plate is at the second position, the light is directed from the light source to the comparison cell. In a comparative light analyzer for analyzing a substance by intercepting light and projecting light from a light source to a sample cell and projecting light from the light source alternately to a comparison cell and a sample cell, the light source side of the sector plate Face to the light used for analysis It is characterized in that it has a mirror surface.

[0008]

According to this structure, since the light from the light source radiates vertically toward the sector plate, for example,
When the sector plate is in the first position, light emitted from the light source other than the light projected to the comparison cell and irradiated to the sector plate is vertically reflected because the sector plate is a mirror surface. It returns to the light source along the same optical path, raises the temperature of the light source element, increases the amount of infrared radiation, is reflected by the reflector on the paraboloid of revolution of the light source, and is used for projection to the cell (comparative / sample cell) Therefore, the use efficiency of the light source is improved. Further, the light projected from the light source onto the sector plate is reflected by its mirror surface and the projected light is not converted into heat, so that the temperature rise of the sector plate is suppressed. On the other hand, when the sector plate is in the second position,
Of the light from the light source other than those projected to the sample cell, the light irradiated to the sector plate is, as described above,
The reflected light is returned to the inside of the light source, and is used for projection to a cell (comparative / sample cell). Therefore, the use efficiency of the light source is improved, and the temperature rise of the sector plate is suppressed.

The light reflected by the paraboloid of reflection mirror from the light source element at the focal position of the paraboloid of reflection mirror is projected perpendicularly to the sector plate. For this reason, most of the light other than the light applied to the cell is reflected vertically by the mirror surface of the sector plate and returns to the light source along the same optical path, and the light returned to the light source is rotated and released. Since the light is re-reflected by the reflecting mirror on the object surface and projected perpendicularly to the sector plate, it does not become stray light.

[0010]

FIG. 1 is a sectional view showing an essential part of an infrared gas analyzer according to one embodiment of the present invention. The general structure and operation of this embodiment are basically shown in FIGS. This is the same as the conventional infrared gas analyzer shown in FIG. This embodiment is different from the conventional infrared gas analyzer in that the rotating sector 2
The point of this embodiment is that the surface on the light source side of No. 0 is black in contrast to the black surface in the prior art. That is, in the present embodiment, as shown in FIG. 1B, which is a plan view of the rotating sector 20, when the infrared light passes through the opening 20a and is projected on the comparison cell 11, the light from the light source 14 is emitted. 20c of the rotating sector 20 to be irradiated with infrared rays, and
The area 20d of the rotating sector 20 to which the light from the light source 14 is irradiated when the light passes through 0b and is projected onto the sample cell 12 is a mirror surface. The mirror surface area is not limited in this way, and the entire surface on the light source side of the rotating sector 20 may be a mirror surface, and the entire area irradiated with light from the light source 14 when the rotating sector 20 is rotating. (A region 20e indicated by oblique lines in FIG. 1C) may be a mirror surface.

Now, as shown in FIG.
When the infrared rays from the laser beam pass through the opening 20d of the rotating sector 20 and are projected onto the sample cell 12 (the rotating sector 20 is
(A case where the position is rotated by 180 degrees from the position shown in (b)) is considered. In this case, most of the infrared rays from the light source 14 other than those projected to the sample cell 12 are irradiated to the rotating sector 20.
Is not converted to heat and returns to the light source 14 because it is a mirror surface.
The infrared light returned to the light source 14 is reflected by the reflecting mirror 14b in the light source and enters the sample cell 12, or the temperature of the light source element 14a is increased to increase the amount of infrared radiation of the light source 14, and eventually the sample cell 12 will be used. In addition, since the infrared rays applied to the rotating sector 20 are reflected and are not converted into heat, the temperature of the rotating sector 20 is lower than in the related art, and infrared rays emitted from the rotating sector 20 are suppressed.

Next, consider a case where infrared light from the light source 14 passes through the opening 20a of the rotating sector 20 and is projected onto the comparison cell 11 (when the rotating sector 20 is at the position shown in FIG. 1B). . In this case, most of the infrared rays from the light source 14 other than those projected to the comparison cell 11 are irradiated to the rotating sector 20.
Since 0 is a mirror surface, it returns to the light source 14 without being converted into heat and is used for projection to the comparison cell 11. Further, similarly to the above, the infrared rays radiated from the rotating sector 20 are suppressed.

As described above, according to the present embodiment, the infrared light applied to the rotating sector 20 is reflected and returns to the light source 14.
Since the light source 14 is used for projection to the cells 11 and 12, the use efficiency of the light source 14 is improved. In addition, since the rotating sector 20 itself can be prevented from being an infrared radiation source, stable analysis can be performed.

The light source is a parabolic reflecting mirror 14b.
And the light source element 14a arranged at the focal point of the reflecting mirror 14b on the paraboloid of revolution, so that most of the light emitted from the light source element 14
The light emitted from the light source 14 is projected perpendicularly to the rotating sector 20 because the light goes to the two cells 11 and 12 after being reflected at 4b. For this reason, the mirrored rotating sector 20 is used.
Most of the light other than the light irradiated to the cell is reflected vertically and returns into the light source 14 along the same optical path. The light returned into the light source 14 increases the temperature of the light source element 14a at the focal position of the reflecting mirror 14b to increase the amount of infrared radiation of the light source 14, or is reflected by the reflecting mirror 14b and reflected in the cell 11 or 12 Into the cell parallel to the side of the cell. As a result, the light applied to the rotating sector 20 does not become stray light.

[0015]

As described above, according to the comparative optical analyzer of the present invention, the light radiated vertically from the light source to the sector plate is vertically reflected by the mirror surface of the sector plate and returns to the light source in the same optical path. , The temperature of the light source element of the light source is increased to increase the amount of light emission, and cells (comparison cell, sample cell)
Since the light source is used for projection, the light source utilization efficiency is improved. Therefore, the light energy that passes through the sample cell or the comparison cell and reaches the detector can be increased without increasing the intensity of the light source itself, thereby improving the analysis sensitivity. Also, suppress the temperature rise of the sector plate,
Since the energy radiated from the surface of the sector plate can be reduced, stable analysis can be performed.

[Brief description of the drawings]

FIG. 1 is a diagram showing a main part of an infrared gas analyzer according to an embodiment of the present invention.

FIG. 2 is a sectional view showing a main part of a conventional infrared gas analyzer.

FIG. 3A is a plan view showing a positional relationship between a rotating sector, a light source, and a cell in a conventional infrared gas analyzer, and FIG.

[Explanation of symbols]

11 ... Comparison cell 12 ... Sample cell 14 ... Light source (14a: Light source element 14b: Reflecting mirror of paraboloid of revolution) 20 ... Rotating sector (sector plate)

Claims (1)

(57) [Scope of request for utility model registration] 1. A method for emitting light from a single light source vertically toward a side-by-side sample cell and a reference cell and a sector plate disposed between the light source and the sample cell and the reference cell. A light source comprising a reflector having a paraboloid of revolution and a light source element disposed at a focal position of the reflector having a paraboloid of revolution, wherein the light source is directed to the sample cell when the sector plate is at the first position. The light from the light source is projected to the comparison cell when the light is blocked, and the light from the light source is projected to the sample cell while the light traveling from the light source to the comparison cell is located at the second position. In a comparative optical analyzer for analyzing a substance by alternately projecting the same onto a comparison cell and a sample cell, the surface on the light source side of the sector plate is mirrored with respect to light used for analysis. Optical analyzer.