JPS59173734A - Infrared-ray gas analysis meter - Google Patents

Abstract

PURPOSE:To make the whole device small-sized and to handle it easily by using a sample cell obtained by forming spirally a cylindrical tube, and a reference cell. CONSTITUTION:A sample gas and a reference gas flow in from inlets 16a, 21a of a sample cell 13 and a reference cell 14, and flow out of outlets 16b, 21b, respectively. Infrared-rays emitted from a light source 11 are made incident to the cells 13, 14 from incident holes 17, 22 through a chopper 12, and the incident lights are emitted from transmission holes 18, 23, being reflected by the side face of the spiral tube, and made incident to a detector 15. The concentration of the sample gas is detected by comparing the values of both output signals. Since the spiral tube is used as the cell, the whole device becomes small-sized, and also is handled easily.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an infrared gas analyzer that uses infrared radiation to analyze the concentration of components contained in gas.

In general, infrared gas analyzers have advantages such as good stability and the ability to analyze a wide variety of components, so they are widely used in various industrial measurement fields. Such a gas analyzer is usually constructed based on the following principle.

That is, as shown in FIG. 1, a sample cell l, which encloses a sample of the gas to be analyzed, is provided on one axis connecting an infrared light emitting section 5 and a light receiving section 6.

The sample cell 2 is usually formed in a cylindrical shape, and both ends thereof are closed by a translucent member 2 that transmits infrared rays. The sample gas enters through a gas port 3 provided in the sample cell I, passes through the interior thereof, and is discharged through a gas outlet 4.

On the other hand, infrared rays enter the sample cell I through the light emitting section 5, pass through the sample gas (7, and are transmitted to the light receiving section 6 on the opposite side).

By measuring the attenuation rate of the wavelength of the infrared rays detected by the light receiving section 6, it is possible to know how much each wavelength range in the infrared region, which varies depending on the components in the sample gas, is absorbed. In this case, although not shown, a reference gas (usually nitrogen gas, etc. that does not absorb infrared rays)
A common method is to provide a reference cell containing a sample gas and compare the transmitted light intensity of each infrared ray that has passed through both the reference cell and sample cell I to find out the concentration of the components contained in the sample gas.

By the way, when the gas to be analyzed is dilute and its concentration is to be measured, it is necessary to extend the length of the 3.1 sample cell 2, which may be as long as 1 m, for example. This is because concentration measurement is performed by detecting changes due to infrared absorption, ie, changes in the amount of transmitted light, as described above, and therefore requires a long optical path length. However, the conventional apparatus has drawbacks such as the size of the entire apparatus increases depending on the length of the sample cell 1, an increase in the occupied itn product, and the handling of the apparatus becomes difficult.

The present invention was made in view of the above circumstances, and its purpose is to reliably control the concentration of components contained in the gas by realizing a long optical path length with a small sample cell, even when the target to be analyzed is a dilute gas. An object of the present invention is to provide an infrared gas analyzer that can realize miniaturization of the entire device and ease of handling.

An embodiment of the present invention will be described below with reference to the drawings. FIG. 2 shows the configuration of an infrared gas analyzer according to the present invention. I2 is a light source 11 that emits infrared rays. The infrared rays emitted from the light source 11 are converted from continuous light to intermittent light by a chopper Z2 formed in the shape of a disc with slits. This chopper z2 is normally rotated by a motor (not shown). Further, behind the chopper I2, a →F sample cell 13 for the sample gas to be analyzed and a reference cell 14 for the reference gas are arranged vertically close to each other. A detector 15 is provided behind each of the arrows 13 and 14 to detect the measured value and emit a signal. Gas inlet 16a that opens upward, consisting of 13 sample cells formed by spirally forming cylindrical tubes.
and a gas outlet Aro b.

The inner surface of the sample cell 13 is, for example, vapor-deposited with aluminum, and is further coated with a 5I02 oxide film as a rust preventive measure. In this case, instead of aluminum, gold,
It is also effective to use silver, copper, etc. Further, at both ends of the sample cell I3, there are provided an entrance hole Z2 and a transmission hole 18 that open toward the light source 77 side and the detector I5 side, respectively, and the open ends thereof are connected to a transmission plate I9 having transparency. and 20.

On the other hand, the reference cell z4 for the reference gas is the sample cell I3.
It has a similar structure, with a gas population 212 and a gas outlet 21b.
, an entrance hole 22, a transmission hole 23, and a transmission plate 24, 25, respectively.

In the infrared gas analyzer configured in this way, the sample gas is input from the gas inlet 16a of the sample cell 13 and the gas output 16b is output 17, and the base gas is input from the gas port 21a of the base cell I4 and the gas output is output from the gas output 16b. 21
Take it out from b. Then, the infrared rays emitted by the light source 77 are converted into intermittent light by the chopper 12.
．． 14 into the cell 13.14 through the entrance hole 17.22. The irradiated infrared rays are reflected by the reflective surfaces in each cell 13 and 14 and guided from the moth to the transmission holes 18 and 23. The infrared rays transmitted through the transmission plate 20.25 are simultaneously received by the detection Bxs on the sample gas sample cell 13 side and the reference gas cell I4 side, and are transmitted as signals. By comparing these values, the concentration of the sample gas to be analyzed can be determined.

In this way, sample cell I3 and reference cell I4
Pass through both 1. By detecting each infrared ray, we can compare the transparent stars of each infrared ray.1. You can see changes in infrared absorption due to semblance gas. That is, it is often possible to reliably measure the concentration of components contained in the sample gas. In the present invention, as shown in FIG. 2 above, →F sample cell 1
By forming both the reference cell 13 and the reference cell 14 in a spiral cylindrical tube, it is possible to have a long optical path length while the main bodies of the cells 13 and 14 are miniaturized and short in length. ■Therefore, even if the sample gas to be analyzed is a dilute gas, changes in the intensity of infrared rays in the sample cell 13 can be reliably detected, and as a result, dilute N
Reliably measure the concentration of the components contained in the sample gas.

Detailed explanation above 1. As described above, according to the present invention, in an infrared gas analyzer, a small sample cell and a reference cell with short cell lengths can have a long optical path length. Therefore, even when the target to be analyzed is a dilute gas, the concentration of the components contained in the gas can be reliably measured, and the entire apparatus can be made smaller and easier to handle.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a conventional infrared gas analyzer;
The figure is a configuration diagram of an infrared gas analyzer according to an example of the present invention.

Claims (1)

[Claims] An infrared light source that emits infrared rays, a sample cell formed by spirally forming a cylindrical tube I7 that transmits infrared rays from this infrared light source and encapsulates chimple gas to be analyzed, and a sample cell that emits infrared rays from said infrared light source. A reference cell is formed by spirally forming a cylindrical tube that passes through the sample cell and encloses a reference gas, and a detector that detects each infrared ray transmitted through both the sample cell and the reference cell and output. ．． This is an infrared gas analyzer with a patent.