JPH0421097Y2 - - Google Patents

Description

[Detailed explanation of the invention] (a) Industrial application field This invention relates to a single-light source, single-beam infrared gas analyzer. This invention relates to a gas correlation type non-dispersive infrared gas analyzer that measures gas concentration.

(b) Conventional technology The conventional gas correlation type non-dispersive infrared gas analyzer is
As shown in FIG. 6, a light source 1 and a semiconductor detector 2
A gas correlation cell 3, a sample cell 4, and an optical filter 5 are provided in order from the light source 1 side on the optical path from the light source 1 to the semiconductor detector 2. The gas correlation cell 3 is connected to the motor 6. As shown in FIG.
The gas to be measured is sealed in the chamber 8 at a predetermined partial pressure (concentration), and the other compartment 8 is filled with a gas that does not absorb infrared rays, such as nitrogen (N ₂ ). Further, the surface of the gas correlation cell 3 on the light source 1 side is sealed with a plate-shaped chopper 9 that chops the light from the light source 1, and the surface on the sample cell 4 side is sealed with a gas to be measured side and an inert gas side. It is sealed with a plate-shaped attenuator 10 to balance the amount of light with the outside. Attenuator 10 has 2
Consisting of different types of window materials 11 and 12, one window material 11
is made of a material that attenuates light by an amount equal to the decrease in light intensity due to absorption of light by the gas to be measured sealed in the compartment 7. By configuring the attenuator 10 in this manner, the influence of the harmful components is eliminated and a signal is generated only when absorption of the component gas to be measured occurs in the sample cell 4.
On the other hand, the sample cell 4 is provided with a sample gas introduction path 13 and a sample gas discharge path 14 for introducing and discharging the sample gas into the cell. In addition,
The optical filter 5 is formed to transmit only the infrared absorption band of the component gas to be measured.

(c) Problems to be solved by the invention Since the analyzer described above measures the concentration of the component gas to be measured in the sample cell 4 by rotating the gas correlation cell 3, a mechanism for rotating the gas correlation cell 3 is required. becomes. Furthermore, since the gas correlation cell 3 is heavy, it is difficult to rotate the gas correlation cell 3 at high speed.
Therefore, there was a drawback that the semiconductor detector 2 could only be rotated at a low frequency relative to its characteristics. Furthermore, since the gas correlation cell 3 is provided with two compartments 7 and 8, the structure of the gas correlation cell 3 is complicated. Moreover, adjusting the attenuator 10 was also troublesome.

This idea was made in view of the above circumstances,
The object of the present invention is to provide a gas correlation type non-dispersive infrared gas analyzer that can measure the concentration of a component gas to be measured with a simple structure without rotating a gas correlation cell, and can easily adjust the amount of light.

(d) Means for solving the problem This invention consists of a cylindrical sample equipped with a light source, a cylindrical gas correlation cell filled with the component gas to be measured, a sample gas inlet passage, and a sample gas discharge passage. It is equipped with a cell, an optical filter that transmits only the infrared absorption band of the component gas to be measured, and a semiconductor detector, and the light from the light source that has passed through the gas correlation cell, the sample cell, and the optical filter in this order is transmitted to the semiconductor detector. In a single-light-source, single-beam infrared gas analyzer configured to allow light to enter the light source, the light from the light source is arranged so as to be able to cross the optical path between the gas correlation cell and the light source and rotate around the light source as a substantially parallel light source. a concave first reflecting mirror for reflecting the light to the side opposite to the gas correlation cell; a first reflecting mirror rotating means; A chopper that chops cell-transmitted light at a predetermined period, a chipper rotating means, and a chopper that is provided facing the gas correlation cell via a light source and reflects parallel light from a first reflecting mirror toward the outside of the first reflecting mirror. The gas correlation cell is provided with a second reflecting mirror that adjusts the amount of light reflected from the second reflecting mirror, and a light amount adjusting means that adjusts the amount of reflected light from the second reflecting mirror. This is a single-source, single-beam infrared gas analyzer in which the cylinder width is larger than the vertical and horizontal widths of the first reflecting mirror.

(E) Function This device rotates the first reflecting mirror to alternately make light that has passed through the gas correlation cell and light that has not passed through the gas correlation cell enter the sample cell.
The amount of reflected light from the second reflecting mirror is adjusted to measure the gas concentration of the measurement component within the sample cell.

(f) Examples This invention will be described in detail below based on examples shown in the figures. Note that this invention is not limited to this.

In FIGS. 1 and 2, reference numeral 15 denotes a cylindrical main body case, and a light source 16 is supported by a fixed shaft 17 provided inside the main body case 15 near one end inside the case. Near the light source 16,
A concave first reflecting mirror 18 is arranged to reflect the light from the light source 16 and emit it as a parallel beam. It is supported so as to be rotatable around the light source 16 by a movably mounted pivot shaft 19 . Main body case 1 of rotating shaft 19
A rotating plate 20 is horizontally attached near the outer end of the rotating plate 20, and a U-shaped sensor 21 is provided near the outer peripheral edge of the rotating plate 20. This sensor 21
The rotating plate 20 is for detecting the direction of the first reflecting mirror 18. Further, a stepping motor 22 for rotating the first reflecting mirror 18 is attached to the upper end of the rotating shaft 19. This motor 22 and rotating shaft 19 constitute a rotating means.

On the optical path in one direction from the light source 16, the light source 16
A gas correlation cell 23, a sample cell 24, an optical filter 25, and a semiconductor detector 26 are provided in this order from the side, and the first reflecting mirror 18 crosses the optical path between the light source 16 and the gas correlation cell 23 when rotated. It is supported as such. The gas correlation cell 23 consists of a sealed cylinder whose both ends are sealed with window materials 27, 27 that can transmit infrared rays. It is formed. Furthermore, a gas to be measured is sealed inside the gas correlation cell 23 . The sample cell 24 is
It consists of a cylinder formed by dividing the inside of the main body case 15 with two window materials 28 and 28 that can transmit infrared rays, and the cylinder wall has a sample gas introduction path 29 and a sample gas discharge path 30 that open into the cylinder. is provided,
The diameter of the cylinder is larger than the vertical and horizontal widths of the first reflecting mirror 18. The optical filter 25 and the semiconductor detector 26 are provided outside the main body case 15,
The optical filter 25 is a filter that selectively transmits the infrared absorption band of the measurement component gas in the sample gas.

A chopper 31 that crosses the optical path between the sample cell 24 and the optical filter 25 and chops the light transmitted through the sample cell at a predetermined period is rotatably provided outside the main body case 15 outside the optical path. As shown in FIG. 4, the chopper 31 is made of a gear-shaped disk, and is rotated by a chopper motor 32 provided outside the main case 15.

At the end inside the main body case 15 on the side facing the gas correlation cell 23 via the light source 16, there is a second reflecting mirror 33 that reflects the parallel light rays from the light source 16 to the outside of the first reflecting mirror 18. It is provided so that it can be slidably moved. The second reflecting mirror 33 is shown in FIGS. 3a and 3b.
As shown in the figure, it consists of a square plate, and its reflective surface consists of a V-shaped groove formed around its center.
Moreover, the amount of light from the light source 18 can be adjusted by slidingly moving the second reflecting mirror 33. That is, the light amount adjusting means is the second reflecting mirror 33.
It is constructed by the sliding movement of. In addition, as a light amount adjusting means, a second reflecting mirror 3 is used as shown in FIG.
A light amount adjuster 35a may be provided between the second reflecting mirror 33 and the sample cell 24 to provide a reflection optical path of the second reflecting mirror 33. 34 is an optical filter 25 inside the main body case 15
It is a light converging part provided with a side end.

Next, how to use the above analyzer will be explained.

First, the partial pressure (concentration) of the gas filled in the gas correlation cell 23 is adjusted so as to eliminate the influence of the interfering gas coexisting in the sample gas. Next, the second reflecting mirror 33 is moved to the light source 18 side, and the amount of attenuation of the light from the first reflecting mirror 18 due to the filled gas and the second reflecting mirror 33 are changed.
The amount of light transmitted through the sample cell 24 and the amount of light attenuation are balanced. Then, the concentration of the measurement component gas in the sample gas is measured by generating a signal only when the light from the second reflecting mirror 33 changes due to absorption of the measurement component gas in the sample gas.

As described above, light passing through the gas correlation cell 23 and light not passing through the cell 23 can be obtained by simply rotating the first reflecting mirror 18 without rotating the gas correlation cell 23. Further, the balance of light quantity can be adjusted simply by moving the second reflecting mirror 33. Therefore, there is no need to attach an attenuator to the gas correlation cell as in the conventional case, and the amount of light can be easily adjusted. Furthermore, since the tipper 31 is plate-shaped, it is possible to tip the signal with a simple structure, and since the tipper can be rotated at high speed, the S/
The N value can be improved.

(g) Effects of the invention According to this invention, the concentration of the gas component to be measured in the sample gas can be measured with a simple structure without rotating the gas correlation cell, and the amount of light can be easily adjusted. I can do it.

[Brief explanation of the drawing]

Fig. 1 is a configuration explanatory diagram including a cross section of the main part showing an embodiment of this invention, Fig. 2 is an enlarged view of section A in Fig. 1,
Figures 3a and b show a plan view and a side view of the second reflecting mirror used in this invention, Figure 4 is a plan view of the tipper used in this invention, and Figure 5 shows another embodiment of this invention. 6 is a perspective view illustrating the configuration of a conventional example, and FIG. 7 is an exploded perspective view of a conventional gas correlation cell. 16...Light source, 18...First reflecting mirror, 19,2
2... Rotating means, 23... Gas correlation cell, 24...
...Sample cell, 25...Optical filter, 26...Semiconductor detector, 29...Sample gas introduction path, 30...
Sample gas discharge path, 31...Chopper, 32...Chopper motor, 33...Second reflecting mirror, 35a...
Light amount adjuster.

Claims (1)

[Claims for Utility Model Registration] A light source, a cylindrical gas correlation cell filled with a component gas to be measured, a cylindrical sample cell equipped with a sample gas introduction path and a sample gas discharge path, and a component gas to be measured. A unit comprising: an optical filter that transmits only an infrared absorption band of In a single-beam infrared gas analyzer, the light source is installed so that it can rotate around the light source, crossing the optical path between the gas correlation cell and the light source, and converting the light from the light source into a substantially parallel beam on the opposite side of the gas correlation cell. a concave first reflecting mirror, a first reflecting mirror rotating means, and a first reflecting mirror rotating means, which is rotatably provided outside the optical path and crosses the optical path between the sample cell and the optical filter to transmit the light transmitted through the sample cell at a predetermined period. a chopping chipper; a chopper rotating means; a second reflecting mirror that is provided opposite the gas correlation cell via a light source and reflects the parallel light beam from the first reflecting mirror toward the outside of the first reflecting mirror; and a light amount adjusting means for adjusting the amount of reflected light from the second reflecting mirror, the cylinder width of the gas correlation cell is formed to be equal to or less than the vertical and horizontal widths of the first reflecting mirror, and the cylinder width of the sample cell is adjusted to the first reflecting mirror. A single-source, single-beam infrared gas analyzer characterized by being larger than the length and width of the mirror.