JPS604111Y2 - infrared gas analyzer - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an improvement of an infrared gas analyzer that analyzes components contained in a gas using absorption of infrared rays.

In general, an infrared gas analyzer using a semiconductor photodetector is configured to collect a reference light transmitted through a reference cell and a measurement light transmitted through a measurement cell onto the photodetector using only a concave mirror.

However, the light source has a certain size, a concave mirror with an ideal concave surface cannot be used for reasons such as price, and it is difficult to arrange the photodetector so that it exactly matches the focal point of the concave mirror. For these reasons, in conventional infrared gas analyzers of this type, measurement light and reference light were not efficiently collected on the photodetector element.

For this reason, the amount of light reaching the photodetector element has been increased by increasing the size of the device by using a high-output infrared source or by increasing the size of the measurement cell and reference cell.

The purpose of the present invention is to realize a compact infrared gas analyzer by efficiently concentrating measurement light and reference light onto a photodetection element.

The present invention will be explained in detail below with reference to the drawings.

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

In the figure, 1 is an infrared source, 2 is a measurement cell filled with a sample gas, and 3 is a reference cell filled with a gas inert to infrared rays.

There are windows 21 and 22 on both sides of the measurement cell 2 that transmit infrared rays.
An inlet 23 and an outlet 24 for introducing and extracting sample gas are provided.

Furthermore, windows 31 that transmit infrared rays are provided at both ends of the reference cell 3.
．． 32 are provided.

4 is a concave mirror that provides infrared rays generated from infrared source 1 to measuring cell 2 and reference cell 3 as parallel rays; 5 is a sector that intercepts the parallel rays at regular intervals; 6 is a motor that rotates this sector; 7 is a photodetector element , 8 is a concave mirror for collecting infrared rays that have passed through the measurement cell 2 and the reference cell 3 onto the photodetecting element 7.

9 is a block disposed between the concave mirror 8 and the photodetector element 7, and FIG. 2 is an enlarged view thereof.

This block 9 has a conical condensing hole 91 with a smooth inner surface.

Further, a hole 92 communicating with the light collecting hole 91 is formed at the end of the light collecting hole 91, and the photodetecting element 7 is inserted into this hole 92.
After being inserted into the block 9, it is fixed to the block 9.

10 is an infrared interference filter attached to the block 9 so as to close the opening of the condensing hole 91.

The infrared ray source 1, concave mirror 4, sector 5, motor 6, photodetecting element 7, concave mirror 8, block 9, and filter 10 are arranged coaxially.

The operation of the device of the present invention configured as described above will be explained.

First, when the sector 5 is in the position shown in FIG. It reaches element 7.

Next, the sector 5 rotates 180 degrees from the position shown in FIG. The light then reaches the photodetector element 7 as a reference light.

Therefore, the infrared rays that are partially absorbed by the measurement cell 2 and the infrared rays that are not absorbed at all through the reference cell 3 alternately enter the photodetection element 7, and the output amplitude of the photodetection element 7 is determined by the concentration of the measured gas. It corresponds to

In this device of the present invention, even infrared rays that would not normally reach the photodetecting element 7 reach the photodetecting element 7 due to the function of the condensing hole 91.

According to experiments, it is easy to obtain about twice the amount of light that reaches the target.

Therefore, it is possible to realize a compact analyzer with sensitivity comparable to that of conventional devices.

Moreover, an expensive concave mirror 8 is not required, and furthermore, there is no need for troublesome work such as arranging the photodetector element 7 so as to perfectly match the focal point of the concave mirror 8.

In addition, in the above description, a block 9 in which a conical condensing hole 91 is formed is used, but the condensing hole 9
The shape of 1 does not need to be a strict conical shape, and the same effect can be obtained as long as it approximates a conical shape.

Also, although the example using one filter was shown,
The present invention can also be applied to those using multiple devices.

In this case, the block 9 may be provided with condensing holes in accordance with the number of filters.

As explained above, according to the present invention, measurement light and reference light can be efficiently collected on the photodetecting element, so a compact infrared gas analyzer can be realized.

[Brief explanation of the drawing]

FIG. 1 is an enlarged view showing a block 9 in FIG. 1, and FIG. 2 is an enlarged view showing a block 9 in FIG. 1...Infrared source, 2...Measurement cell, 3
...Reference cell, 4...Concave mirror, 5...
...Sector, 6...Motor, 7...
・Photodetection element, 8... Concave mirror, 9...
Block, 91... Focusing hole, 10...
Infrared interference filter.

Claims (1)

[Claims for Utility Model Registration] 1. In an infrared gas analyzer configured to collect reference light and measurement light onto a photodetecting element using a concave mirror, a block in which a condensing hole is formed is connected to the concave mirror and the photodetecting element. An infrared gas analyzer placed between the 2. The infrared gas analyzer according to claim 1, which is a registered utility model and uses a block in which a hole for accommodating a photodetection element is formed at the end of a condensing hole.