JPH1172428A - Pneumatic golay cell - Google Patents

Abstract

PROBLEM TO BE SOLVED: To speed up exchange of gases and facilitate adjustment of a frequency characteristic, by setting an adjusting means adjusting an inner diameter of a predetermined point suitably at the predetermined point of a communication hole between an absorption chamber and an outer chamber via a variable mirror. SOLUTION: A pneumatic Golay cell 116 used in a non-dispersive infrared absorption method, etc., has an adjusting means 164 of, e.g. a needle valve at a predetermined point 154a of a communication hole 154 between an absorption chamber 126 and an outer chamber 150. When gases are exchanged, the adjusting means 164 is moved to expand an inner diameter of the predetermined point 154a. The inner diameter of the predetermined point 154a is made approximately equal to an inner diameter of a rear part 154b to discharge or feed the gas. After the gases are exchanged, a size of the predetermined point 154a is adjusted with the use of the adjusting means 164 so that the Golay cell 116 has a suitable frequency characteristic. Since the frequency characteristic can be adjusted without disassembling the cell, a main body 166 of the Golay cell 116 is constituted as an integral sealed case, whereby a leak of the sealed gas is lessened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a new match Golay cell, and more particularly to an improvement of a frequency characteristic adjusting mechanism.

[0002]

BACKGROUND ART Generally made from different atomic molecules (e.g. carbon monoxide CO, carbon dioxide CO ₂₎ are respectively have the property of absorbing infrared light of specific wavelength. A non-dispersive infrared absorption method is a method for selectively measuring the concentration of a gas utilizing this characteristic, and is often used as a continuous concentration analyzer for a process. As an example of such a continuous concentration dispersometer, for example, a gas analyzer shown in FIG. 1 is known. In the gas analyzer shown in FIG. 1, a sample cell 14 containing a sample gas is provided in front of the light source 12 in the light emitting direction, and the infrared light L1 having a specific wavelength absorbed in the sample cell 14 is Newmatch. It is incident on the Ku Golay cell 16.

Here, of the infrared light L1 incident on the New Matchk Golay cell 16 according to the concentration of the sample gas,
The amount of light in the absorption band of the sample gas decreases, and the absorption response of the new match Golay cell 16 changes. This is extracted as a signal from the New Match Golay cell 16. The extracted signal is amplified by the amplifier 18 and the indicator 20
Indicates the concentration. FIG. 2 is an enlarged view of the new match gore cell 16. In the Golay cell 16 shown in the figure, when the infrared light L1 from the sample cell 14 passes through the incident window 22 and is absorbed by the absorption film 24, the gas sealed in the absorption chamber 26 is heated, and the absorption chamber 26 is heated. The internal pressure is raised to cause the variable mirror 28 to bend.

On the other hand, the light L2 from the built-in light source 38 transmitted through the entrance window 36 through the lenses 30, 32 and the grid 34 shown in FIG. Variable mirror 2 curved according to
8 and is transmitted again through the lens 40 and the entrance window 36 to project a grid image on the grid 34 shown in FIG. 1, so that the change in the combined focal length of the variable mirror 28 and the lens 40 is , The intensity of the infrared light L1 from the sample cell 14 can be detected. Also, as shown in FIG. 2, an O-ring 48 made of an elastic body is provided between an outer frame 44 for holding the entrance window 22 and an outer frame 46 for holding the entrance window 36. It was kept airtight.

In general, in a New Match Golay cell, a gas such as xenon (Xe) is sealed in the cell in order to improve the detection sensitivity. That is, in the conventional New Match Golay cell 16 shown in FIG. It was led out and the inside of the cell was evacuated. Then, after the inside of the cell is evacuated, a gas such as xenon (Xe) is sealed in the chambers 26, 50, and 52 from the supply / exhaust pipe 60 through the communication holes 54, 56, and 58, and the gas is exchanged. I was

[0006]

However, in the New Match Gore cell 16 having the conventional structure, the gas exchange speed is about 1 mmHg / sec.
As described above, it took about 10 hours to completely replace the gas inside the cell, which was not satisfactory in terms of speed. The reason is that the variable mirror 28 is made of a very thin film so as to be appropriately curved in response to a slight pressure change in the absorption chamber 26, so that the variable mirror 28 is interposed therebetween. The gas must be exchanged so that the pressure difference between the chambers 26 and 50 provided on both sides is reduced as much as possible so that the deformable mirror 28 is not broken.
This is because in No. 6, the pressure had to be about 1 mmHg / sec.

That is, the communication hole 54 is originally for determining the frequency characteristic, and the other communication holes 5
It is provided with a very small diameter as compared with 6,58. The small diameter of the communication hole 54 is a preferable size for determining the frequency characteristics, but is too narrow when the gas is exchanged, so that the gas exchange speed is limited.

Further, since the communication hole 54 is provided with a very small diameter as compared with the other communication holes 56 and 58, when the gas is led out, compared with the gas in the absorption chamber 26, the communication hole 54 has a smaller diameter. Since the gas in 52 is preferentially led out of the cell, the pressure in chamber 50 is lower than the pressure in absorption chamber 26.

On the other hand, when the gas is introduced, the gas from the supply / exhaust pipe 60 is introduced with priority on the communication pipes 56 and 58 as compared with the communication pipe 54. When the gas is exchanged, the flow rate is increased, for example, by about 1 m.
When the pressure is not less than mHg / sec, there is a high possibility that a pressure difference will occur between the chambers 26 and 50 provided on both sides of the variable mirror 28 with the variable mirror 28 interposed therebetween, thereby increasing the possibility that the variable mirror 28 will be broken. It is because.

Further, as described above, the communication hole 54 is originally
Since it is for determining the frequency characteristics, it was not possible to greatly change the size of the diameter only for performing high-speed gas exchange. Further, in the above-mentioned conventional New Match Golay cell 16, the communication hole 54 for determining the frequency characteristic is considered before the variable mirror 28 is attached to the table 62, depending on the experience and feeling of a skilled person. It is processed, but this frequency characteristic, assemble the cell,
If the measurement is not performed after the gas is further exchanged, it cannot be known.

Therefore, if it is desired to change the frequency characteristics of the completed New Match Golay cell 16 for adjustment, it is necessary to disassemble it, process the size of the communication hole 54 again, and then reassemble it. there were. Moreover, this has to be repeated until a desired frequency characteristic is obtained, which is not satisfactory from the viewpoint of workability.

Furthermore, in the above-mentioned conventional New Match Golay cell 16, the sealed gas gradually leaks during use for a long time. Particularly, in the case of a gas-filled type in which a gas to be detected is sealed instead of the absorption film 24 of the absorption chamber 26, the problem of leakage of the sealed gas is remarkably manifested as a change in absorbance with a decrease in sensitivity, resulting in unstable measurement. Therefore, there was still room for improvement from the viewpoint of airtightness, but the cause could not be identified. SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems of the related art, and has as its object the purpose of increasing the speed of gas replacement, facilitating adjustment of frequency characteristics, and further improving airtightness. The object of the present invention is to provide a new match Golay cell that can achieve the goal.

[0013]

In order to achieve the above object, a new match Golay cell according to the present invention is provided on one side with a variable mirror interposed therebetween, and the variable mirror is provided in accordance with the amount of incident external light. And an outer chamber provided on the opposite side of the absorbing chamber with the variable mirror interposed therebetween, and a communication hole communicating between the two chambers. The frequency characteristic of the variable mirror is determined by allowing a part of the gas in the absorption chamber to escape into the outer chamber via the communication hole, and at least one of the two chambers is determined via the communication hole. In the New Match Golay cell for replacing the gas in the inside, it is provided at a predetermined location of the communication hole, and appropriately adjusts the inner diameter of the location when adjusting the frequency characteristic and when replacing the gas. Characterized by comprising the capability of adjusting means.

The "adjusting means capable of appropriately adjusting the inner diameter of a predetermined portion of the communication hole" as used herein means, for example, that when the gas is exchanged, the inner diameter of the predetermined portion of the communication hole is adjusted by the adjusting means. When the frequency characteristic is adjusted to be relatively wide and the frequency characteristics are adjusted, the adjusting means can be adjusted so that the inside diameter of a predetermined portion of the communication hole becomes relatively small. In the New Match Golay cell, the adjusting means is a valve stem provided so as to be able to adjust a gap with a predetermined portion of the communication hole, and the predetermined portion of the communication hole is connected to the communication hole by the valve stem. It is preferable that the size of the inner diameter can be appropriately adjusted by adjusting the gap between the hole and a predetermined portion.

In the New Match Golay cell, when the gas is exchanged, the size of the inside diameter of a predetermined portion of the communication hole is adjusted by the adjusting means so that the inside diameter of the communication hole becomes substantially the same as an arbitrary portion of the communication hole. It is preferred to adjust. Here, "adjusting the size of the inner diameter of a predetermined portion of the communication hole so as to have substantially the same inner diameter as an arbitrary portion of the communication hole" means that when the gas is exchanged, the variable mirror is interposed. Means adjusting the size of the inner diameter of a predetermined portion of the communication hole so that a pressure difference does not occur between the chambers provided on both sides.

In the New Match Golay cell, it is preferable that at least the two chambers and the communication hole are disposed in a substantially integral closed case. Here, "at least the two chambers and the communication hole are disposed in a substantially integral closed case."
This means that the constituent members of the New Match Golay cell are arranged in a substantially integral closed case.

The term "new match Golay cell" as used herein does not particularly limit the type of Golay cell, but is provided on one side with a variable mirror interposed therebetween. Any one provided with an absorption chamber capable of bending the external mirror, an outer chamber provided on the opposite side of the absorption chamber with the variable mirror interposed therebetween, and a communication hole communicating between the two chambers Non-dispersive infrared gas analysis method in which a specific gas is sealed in the chamber instead of a normal infrared detector in which an absorption film is provided in the chamber, or in place of this absorption film. (NDI
R) includes those that can be used as detectors.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. 3 and 4 show a schematic configuration of a new match Golay cell according to an embodiment of the present invention. FIG. 3 is an explanatory view of the intake / exhaust state of the New Matchk Golay cell according to the present embodiment, and FIG. 4 is an explanatory view of a similar New Matchk Golay cell filled with gas. Also, portions corresponding to those in FIG. 2 are denoted by reference numerals 100, and description thereof is omitted.

New Match Gorecel 1 shown in FIG.
16 is provided at a predetermined position 154a of the communication hole 154,
There is provided an adjusting means 164 capable of appropriately adjusting the size of the inner diameter of the predetermined portion 154a by adjusting the frequency characteristics and exchanging the gas. In the present embodiment, the adjusting means 164 is formed by a needle valve having a pointed tip 164a. By moving the adjusting means 164 in the vertical direction in the drawing, a predetermined portion 154a of the communication hole 154 is formed.
The size of the inside diameter is adjustable. Further, in the present embodiment, when the gas is exchanged, the communication hole 154 is formed by moving the adjusting means 164 in the vertical direction in FIG. The size of the inner diameter of 154b can be made substantially the same.
Further, in the present embodiment, as shown in FIG. 3, each constituent member of the New Match Golay cell 116 is arranged in a main body 166 which is a substantially integrated closed case.

The new match Golay cell 116 according to this embodiment is configured as described above, and its operation will be described below. Improvement of adjustment of gas replacement time and frequency characteristics New match gore cell 116 according to the present embodiment
According to this, the size of the inner diameter of the predetermined portion 154a of the communication hole 154 can be appropriately adjusted by the adjusting means 164, and the gas is exchanged through the communication hole 154a and the frequency characteristics are adjusted. Therefore, it is possible to speed up the replacement of the gas and to easily adjust the frequency characteristics. That is, when changing the gas, as shown in FIG. 3, when the adjusting means 164 is moved upward in the figure, a predetermined portion 154a of the communication hole 154 is formed.
The size of the inside diameter gradually increases, and the gas is exchanged after the inside diameter of the predetermined portion 154a of the communication hole 154 and the inside diameter of the subsequent side 154b are made substantially the same.

Then, taking the case of gas introduction as an example, the gas introduced from, for example, the supply / exhaust pipe 160 first passes through the communication hole 1.
The flow is divided into a predetermined portion 154a and a subsequent side 154b. Here, the communication hole 154 is adjusted by the adjusting means 164.
Since the inner diameter of the predetermined portion 154a is substantially the same as the inner diameter of the downstream side 154b, the gas introduced into the absorption chamber 126 through the predetermined portion 154a of the communication hole 154 and the downstream side 154b Thus, the flow rate of the gas introduced into the chamber 150 (outer chamber) via the communication hole 156 can be made substantially the same. By setting the flow rate of the gas introduced into the absorption chamber 126 and the flow rate of the gas introduced into the chamber 150 to be substantially the same, at the time of replacing the gas, the variable mirror 128 is provided on both sides with the variable mirror 128 interposed therebetween. Chamber 12
The pressure between 6,150 can be approximately the same.

Therefore, even if the gas flow rate is much higher than the conventional limit of about 1 mmHg / sec, there is substantially no pressure difference between the chambers 126 and 150, so the gas replacement time ( In this embodiment, 1
It is possible to greatly increase the speed of the operation (the time is possible without any problem). In this case, the rear side 1 of the communication hole 154
The gas passing through 54b is introduced not only into the chamber 150 through the communication hole 156 but also into the chamber 152 through the communication hole 158, as described above. Can be exchanged favorably.

Next, after the gas replacement is completed, the size of the predetermined portion 154a of the communication hole 154 is gradually reduced by moving the adjusting means 164 downward in the figure as shown in FIG. Predetermined location 1 of communication hole so as to obtain characteristics
Only by adjusting the size of 54a (for example, substantially the same as the inner diameter of the communication hole 54 in FIG. 2), the frequency characteristics can be easily and appropriately adjusted without disassembling the cell. That is, when the infrared light L1 passes through the entrance window 122 and is heated by the absorption film 124, the absorption chamber 126
The gas enclosed therein is warmed, the pressure in the absorption chamber 126 is increased, and the variable mirror 128 is bent, and a part of the gas in the absorption chamber 126 is changed over time to a predetermined position 154 a and a predetermined position 154 a of the communication hole 154. It can escape to the inside of the cell via the downstream side 154b.

Here, when it is desired to increase the frequency characteristic of the variable mirror 128, the adjusting means 164 is slightly moved upward in the figure to adjust the size of the inner diameter of the predetermined portion 154a of the communication hole 154 to be slightly larger. As a result, the gas in the absorption chamber 126 easily passes through the predetermined portion 154a of the communication hole 154,
If it is desired to delay this frequency characteristic, the adjusting means 164
Is slightly moved downward in the figure to adjust the inner diameter of the predetermined portion 154a of the communication hole 154 to be slightly smaller, so that the gas in the absorption chamber 126 is less likely to pass through the predetermined portion 154a of the communication hole 154. This makes it possible to adjust the desired frequency characteristics properly and without disassembling the cell.
64 can be easily adjusted only by moving it up and down in the figure.

As described above, according to the New Match Golay cell 116 according to the present embodiment, the size of the inner diameter of the predetermined portion 154a of the communication hole 154 can be appropriately adjusted by the adjusting means 164. The speed can be increased, and the frequency characteristics can be easily adjusted.

The leakage improves the inventors of the filling gas is a result of intensive study for leak problem of the filler gas, the diagram showing a conventional 2 Golay cell 1
In No. 6, it is specified that there is one factor in the leakage of the sealing gas from the O-ring 48 interposed between the outer frame 44 and the outer frame 46, and it is specified that the conventional O-ring 48 is not provided. The present inventors have found that the airtightness in the main body can be improved by integrally molding the main body and fixing the entrance windows directly to both ends of the main body with an adhesive or the like, and have completed the present invention.

For this reason, in the present embodiment, the main body 1
66 is a substantially one-piece sealed case.
Openings are provided at both ends of 66, and entrance windows 122 and 136 are fixed to the openings with an adhesive or the like, respectively, to keep the inside of the main body 166 airtight. In addition, in the configuration in which the main body 166 is formed as an integral closed case, the frequency characteristics after the cell assembly is changed as described above, and the adjusting means 164 can be used without disassembling the cell.
The size of the inner diameter of the predetermined portion 154a of the communication hole 154 can be easily adjusted only by moving the communication hole in the middle and up and down directions.

Further, the present inventors can keep the inside of the main body 166 airtight at the other end of the supply / exhaust pipe 160 as shown in FIG. By appropriately providing the airtight means 168,
It has also been found that the airtightness can be improved. For this purpose, in the present embodiment, for example, an adhesive or the like can be used as the airtight means 168. By providing the adhesive which is the airtight means 168 in a state where the end is crushed, the main body 166 is provided.
The filling gas in the inside is controlled by the adjusting means 164 and the supply / exhaust pipe
Leakage to the outside of the cell via 0 can be reliably prevented. As described above, the main body 166 is formed as a substantially integral sealed case, and the other end of the supply / exhaust pipe 160 is sealed as shown in FIG. 4 and further sealed twice by airtight means 168 such as an adhesive. In addition, the leakage of the sealed gas can be significantly reduced.

As described above, according to the New Match Gore cell 116 of the present embodiment, the adjusting means 164 capable of appropriately adjusting the inner diameter of the predetermined portion 154a of the communication hole 154 is provided. The gas exchange can be speeded up without disassembling the cell, and the frequency characteristics can be easily adjusted.

The adjusting means 164 is provided in the communication hole 15.
4 is a valve stem such as a needle valve provided with an adjustable gap between the predetermined location 154a, and the predetermined location 154a of the communication hole 154 is the same as the valve stem such as the needle valve shown in FIG.
4 to 4 in the vertical direction in FIG.
The size of the inside diameter of the predetermined portion 154a of the communication hole 154 can be easily adjusted by adjusting the size of the inside diameter of the communication hole 154 by adjusting the gap between the inside and the outside.

When the gas is exchanged, the size of the inner diameter of the predetermined portion 154a of the communication hole 154 is adjusted by the adjusting means 164 so that the inner diameter of the communication hole 154 is substantially the same as that of the rear side 154b. , The chambers 126 provided on both sides with the variable mirror 128 interposed therebetween,
The pressure difference between 150 can be greatly reduced, and the variable mirror 128 can be largely prevented from being broken by the pressure difference.

Further, the above-mentioned new match gore cell 1
By arranging each of the sixteen components in the main body 166, which is a substantially integral closed case, leakage of the sealed gas from the inside of the main body 166 to the outside can be reliably reduced, and the airtightness can be reduced. Can also be improved. further,
The air supply / exhaust pipe 160 is appropriately provided with airtight means 168 capable of keeping the inside of the main body 166 airtight, whereby the main body 166 is provided.
The airtightness of the inside can be further improved. It should be noted that the new match Golay cell of the present invention is not limited to the above-described configurations, and various modifications can be made within the scope of the present invention.

[0033] To gas-filled New Match Gorecell
In each of the above-described configurations, the case where the absorption film 124 is used has been described. Instead of the absorption film 124, a gas-filled New Matchk Golay cell in which the gas to be detected is filled can be used. As such a gas-filled type New Match Gore cell, for example, Japanese Patent Application Laid-Open No. H8-30
What is described in 4282 gazette is publicly known. The frequency characteristics of such a gas-filled type New Match Golay cell are very important. That is, in the gas analyzer described in the above-mentioned Japanese Patent Application Laid-Open No. 8-304282, how the frequency characteristics of the two New Matchk Golay cells as detectors can be made the same leads to an improvement in the reliability of detection results. Because.

However, the detector shown in FIG.
When the conventional Golay cell 16 shown in FIG. 1 is used, it is necessary to adjust the frequency characteristics by repeating the assembling work and the disassembling work of the two New Match Gore cells 16 a plurality of times.
It was not yet satisfactory in terms of workability. Therefore, by using the New Match Golay cell 116 according to the present embodiment as the detector, the frequency characteristics of the two New Match Golay cells can be adjusted without adjusting the communication holes 154 by the adjusting means 164 without disassembling the cells. It is only necessary to adjust the size of the inner diameter of the predetermined portion 154a, and the workability can be greatly improved.

Further, according to the New Match Gore cell 116 of the present embodiment, the predetermined position 154a of the communication hole 154 can be finely adjusted easily, so that the conventional New Match Gore cell 16 can be used. As compared with the conventional case, the frequency characteristics of the two Golay cells can be adjusted more appropriately, and the reliability of the detection result can be improved.

[0036]

As described above, according to the New Match Golay cell of the present invention, the communication means is provided with an adjusting means capable of appropriately adjusting the inner diameter of a predetermined portion of the communication hole. Gas exchange can be performed at high speed through the holes, and frequency characteristics can be easily adjusted. In the New Match Golay cell, the adjusting means is a valve stem provided so as to be able to adjust a gap with a predetermined portion of the communication hole. The size of the inside diameter of the communication hole can be easily adjusted by adjusting the size of the inside diameter of the communication hole as appropriate by adjusting the gap between the hole and the predetermined portion. .
In the New Match Golay cell, when the gas is exchanged, the size of the inner diameter of a predetermined portion of the communication hole is adjusted by the adjusting means so as to have substantially the same inner diameter as an arbitrary portion of the communication hole. This makes it possible to greatly reduce the pressure difference between the chambers provided on both sides of the variable mirror with the variable mirror interposed therebetween, and to greatly prevent the variable mirror from being broken by the pressure difference. Further, in the New Match Golay cell, by arranging the respective constituent members in a main body which is a substantially integral closed case,
Leakage of the sealed gas from the inside of the main body to the outside can be reliably reduced, and the airtightness can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating an example of a schematic configuration of a general gas analyzer.

FIG. 2 is an explanatory diagram of a schematic configuration of a conventional New Match Golay cell of the gas analyzer shown in FIG. 1;

FIG. 3 shows a new match according to an embodiment of the present invention.
It is explanatory drawing of the supply / exhaust state of a Golay cell.

FIG. 4 is an explanatory diagram of a gas filled state of the New Match Gore cell shown in FIG. 3;

[Explanation of symbols]

 116 New Matchk Golay Cell 126 Absorption Chamber 128 Variable Mirror 150 Chamber (Outer Chamber) 154 Communication Hole 154a Predetermined Location of Communication Hole 154b Rear Side of Communication Hole 160 Supply / Exhaust Pipe 164 Adjusting Means 168 Adhesive (Airtight Means)

Claims (4)

[Claims] Claims: 1. A variable mirror is provided on one side with a variable mirror interposed therebetween,
An absorption chamber capable of bending the variable mirror in accordance with the amount of incident external light, an outer chamber provided on the opposite side of the absorption chamber with the variable mirror interposed therebetween, and a communication communicating between the two chambers And determining a frequency characteristic of the variable mirror by releasing a part of the gas in the absorption chamber into the outer chamber through the communication hole, and determining the frequency characteristics of the variable mirror through the communication hole. In a New Match Golay cell for replacing gas in at least one of the chambers, the New Match Gore cell is provided at a predetermined location of the communication hole, and is used for adjusting frequency characteristics and performing gas replacement. A new match Golay cell comprising an adjusting means capable of appropriately adjusting the size of the inner diameter of the new match. 2. The new match Golay cell according to claim 1, wherein the adjusting means is a valve stem provided with a gap between the communication hole and a predetermined portion thereof, and the predetermined portion of the communication hole is The size of the inner diameter of the communication hole can be appropriately adjusted by adjusting the gap between the communication hole and a predetermined portion by the valve stem. 3. A new match Golay cell according to claim 1 or 2, wherein when the gas is exchanged, the adjusting means has a predetermined diameter of the communication hole such that the communication hole has substantially the same inner diameter as an arbitrary portion of the communication hole. A new match gore cell, characterized by adjusting the size of the inner diameter of the location. 4. The New Match Golay cell according to claim 1, wherein at least both the chambers and the communication hole are disposed in a substantially integral closed case. Mack Golaycel.