TWI716598B - Gas analysis device - Google Patents

Abstract

The subject of the present invention is to reduce the influence of moisture or dust in the analysis target gas.

The solution of the present invention is to provide a gas analysis device comprising: an irradiating part that irradiates the analysis target gas flowing in the flue with laser light, and a light receiving part that is separated from the irradiating part through the flue They are arranged opposite to each other and receive the laser light that has passed through the gas to be analyzed, and the integrated tube is arranged between the irradiating part and the light-receiving part in such a way that the laser light passes through the inside, and in the flue, the tube forms There are a first hole facing the upstream side of the analysis target gas and a second hole facing the downstream side of the analysis target gas.

Description

Gas analysis device

The present invention relates to a gas analysis device.

In the past, laser-type gas analysis devices have been known. The gas analysis device is provided with an irradiating unit that irradiates the analysis target gas with laser light, and a light receiving unit that receives the laser light rays that have passed through the analysis target gas. The gas analyzer analyzes the absorption spectrum based on the amount of light received at the light receiving part. The gas analysis device analyzes the concentration of the target substance in the target gas based on the absorption spectrum (for example, please refer to Patent Document 1).

[Prior technical literature] 〔Patent Literature〕

[Patent Document 1] Japanese Patent Application Publication No. 2009-270917

In a laser-type gas analysis device, when the analysis target gas contains moisture or dust, the laser light will be scattered or absorbed by the moisture or dust. And depending on the amount of moisture or dust, it will decrease It is difficult to measure the concentration of the target substance due to the amount of laser light received by the light receiving unit.

In the same aspect of the present invention, the gas analysis device is preferably provided with: an irradiating part, a light receiving part, and a tube; the irradiating part is preferably irradiating laser light to the analysis target gas flowing in the flue; and the light receiving part is preferably It is better to arrange the light-receiving part facing the irradiating part through the flue; the light receiving part is preferably to receive the laser light that has passed through the analysis target gas; the tube is arranged in the irradiating part so that the laser light passes through the inside. A tube that is integral with the light receiving part is preferred; in the flue, it is better to form the first hole and the second hole in the tube. Preferably, the first hole is facing the upstream side of the analysis target gas; the second hole is preferably facing the downstream side of the analysis target gas.

The gas analysis device is preferably equipped with an introduction part on the irradiating part side and an introduction part on the light receiving part side; an introduction part on the irradiating part side is preferably to introduce the cleaning gas from the end of the tube on the irradiation part side into the tube; Part, it is better to introduce the cleaning gas into the tube from the end of the tube on the light-receiving part side.

The second hole is preferably arranged on the downstream side of the analysis target gas so as to face the first hole; the opening area of the second hole is preferably larger than that of the first hole.

Preferably, the first hole and the second hole have a long axis; and the long axis is preferably extended toward the long side of the cylinder.

The gas analysis device is preferably equipped with a cover part; the cover part is preferably formed separately from the cylinder; the cover part is a part of the first hole Coverage is better.

For the cover part, it is better to cover the central part of the first hole in the longitudinal direction; for the cover part, it is better not to cover the end of the first hole in the longitudinal direction; the first hole is It has a long axis extending toward the long side of the tube.

The hole is preferably formed in the cover part; the hole is preferably used to allow the gas to be analyzed to pass through.

The cover part is preferably to cover the entire first hole; the hole part is preferably formed in the cover part.

It is preferable to form a plurality of holes in the cover part.

The cover part is preferably divided into a plurality of pieces.

It is preferable that the lower end of the cover portion extends to the lower side than the first hole.

In addition, the above-mentioned summary of the invention does not enumerate all the essential features of the invention. Moreover, the subcombination of these feature groups can of course become an invention.

1‧‧‧Analyzing target gas

2‧‧‧Laser light

6‧‧‧Cleaning gas

8‧‧‧Cleaning gas

10‧‧‧ Irradiation Department

12‧‧‧Laser element

14‧‧‧Collimating lens

16‧‧‧Frame

18‧‧‧Light-transmitting window on the side of the irradiation part

20‧‧‧Light receiving part

22‧‧‧Collecting lens

24‧‧‧Light receiving element

25‧‧‧Signal Processing Department

26‧‧‧Frame

28‧‧‧Transmitting window on the side of the light receiving part

30‧‧‧tube

30a‧‧‧The side connecting tube of the irradiation part

30b‧‧‧Light receiving part side connecting tube

32‧‧‧The first hole

34‧‧‧The second hole

36‧‧‧Flange

37‧‧‧Flange

38‧‧‧End

42‧‧‧Imported part side introduction part

44‧‧‧Introduction to the light receiving part

50‧‧‧Cover

52‧‧‧Support

54‧‧‧Bottom

56‧‧‧Kongbu

60‧‧‧ Flue

62‧‧‧Wall

100‧‧‧Gas analysis device

Fig. 1 is a perspective view showing the outline of the gas analyzer 100 in the first embodiment of the present invention.

Fig. 2 is a cross-sectional view of the gas analyzer 100 in the first embodiment of the present invention.

FIG. 3 is a side view of the barrel 30. FIG.

Figure 4 is a top view of the cartridge 30.

Fig. 5 is a side view of the gas analyzer 100 in the second embodiment of the present invention.

Fig. 6 is a cross-sectional view taken along the line AA' of the gas analyzer 100 in the second embodiment of the present invention.

Fig. 7 is a side view showing a modification of the gas analysis device 100 in the second embodiment.

Fig. 8 is a side view showing another modification of the gas analysis device 100 in the second embodiment.

Fig. 9 is a side view showing another modified example of the gas analyzer 100 in the second embodiment.

[Embodiment to implement the invention]

Hereinafter, the present invention will be explained through the embodiments of the invention. However, the following embodiments are not intended to limit the invention described in the scope of the patent application. In addition, it is not limited that all combinations of the features described in the embodiments are necessary for the solution of the invention.

In this patent specification, the X-axis, Y-axis, and Z-axis orthogonal coordinate systems are used to illustrate technical matters. The rectangular coordinate system is only used to specify the relative position of the constituent elements, rather than to limit a specific direction. For example, the Z axis does not mean that it is used to limit the height direction relative to the ground. In addition, the +Z axis direction and the -Z axis direction are directions opposite to each other. When the positive and negative are not recorded, but the Z-axis direction is recorded, it is Refers to the direction parallel to +Z axis and -Z axis.

Fig. 1 is a perspective view showing the outline of the gas analyzer 100 in the first embodiment of the present invention. The gas analysis device 100 is used to analyze the analysis target gas 1 flowing in the flue 60. In this example, the analysis target gas 1 flows in the Z-axis direction. The flue 60 may be a flow path of gas discharged from a boiler or a combustion furnace. Boilers or furnaces can burn coal, heavy oil, or garbage. However, the flue 60 is not limited to a gas flow path. The flue 60 in this patent specification can be a machine containing an internal space for the analysis target gas 1 to flow, or it can be a container, chimney, exhaust duct, denitrification device, chemical plant equipment, and iron and steel plant equipment , And various machines such as heating furnaces.

The gas analysis device 100 may be a direct insertion type laser gas analyzer that extracts the gas for measurement to the outside of the flue 60 and is unnecessary. The gas analysis device 100 includes an irradiating unit 10 and a light receiving unit 20. The irradiating unit 10 and the light receiving unit 20 are arranged outside the flue 60. The irradiating unit 10 and the light receiving unit 20 are arranged facing each other with the flue 60 interposed therebetween. In this example, the irradiation unit 10 and the light receiving unit 20 are arranged along the X-axis direction. The irradiating unit 10 irradiates laser light 2 to the analysis target gas 1 flowing in the flue 60. The light receiving unit 20 receives the laser light 2 after passing through the analysis target gas 1.

The gas analysis device 100 of this example includes a tube 30 that is disposed between the irradiating unit 10 and the light receiving unit 20 as one body. The integral tube 30 refers to a tubular body that connects the irradiation unit 10 and the light receiving unit 20. The integrated tube 30, as long as there is no gap between the irradiating part 10 and the light receiving part 20 It is divided and broken, and it can be constructed by joining a plurality of cylinders. The tube 30 is arranged so that the laser light 2 passes through the inside. In the tube 30 of this example, the longitudinal direction is arranged in parallel to the X-axis direction. In order to prevent the laser light 2 from being interfered by the inner wall of the tube 30, the laser light 2 preferably passes through the vicinity of the central axis of the tube 30.

A first hole 32 and a second hole 34 are formed on the wall of the tube 30. The first hole 32 faces the upstream side of the analysis target gas 1. On the other hand, the second hole 34 faces the downstream side of the analysis target gas 1. The second hole 34 is provided at a position facing the first hole 32. The analysis target gas 1 flows in from the first hole 32 and then flows out from the second hole 34. Therefore, the space area sandwiched by the first hole 32 and the second hole 34 is exposed in the analysis target gas environment. In the space region sandwiched by the first hole 32 and the second hole 34, the laser light 2 passes through the analysis target gas 1. In order to prevent the analysis target gas 1 from flowing into the irradiation unit 10 side and the light receiving unit 20 side, the cleaning gas 6 and the cleaning gas 8 may be introduced into the cylinder 30 from both ends in the X-axis direction of the cylinder 30 toward the center.

The gas analysis device 100 analyzes the absorption spectrum based on the amount of light received by the light receiving unit 20. The gas analyzer 100 analyzes the concentration of the target substance contained in the analysis target gas 1 from the absorption spectrum. The target substance may be gas components such as HCl, NH ₃ , O ₂ , CO, CO ₂ , HF, CH ₄ , NOX, and H ₂ O. In this patent specification, the analysis target gas 1 is not particularly limited. The analysis target gas 1 can be various gases such as dry distillation gas, generated gas, exhaust gas, iron and steel plant gas, process gas, and furnace gas.

The gas analysis device 100 can analyze the concentration of the target substance based on the attenuation of the laser light 2 in a specific wavelength. Specifically, according to the Lambert-Beer law, the attenuation of the laser light 2 depends on the concentration of the target substance and the measurement optical path length of the area where the target substance exists. The Lambert-Beer equation is shown in [Equation 1]. In this example, the measuring optical path length Ls is defined by the length of the first hole 32 in the X-axis direction. Since the processing itself performed by the gas analysis device 100 is the same as that of the conventional laser-type gas analysis device, detailed description is omitted.

[Numerical formula 1] I(L)=I(O). exp〔-ks. Ns. Ls]

Here, I(L) is the amount of received light.

I(O) is the amount of irradiated light (amount of light emitted).

Ks is the gas constant.

Ns is the concentration (vol/%) of the target substance.

Ls is the measuring optical path length.

Fig. 2 is a cross-sectional view of the gas analysis device 100 in the first embodiment of the present invention. Fig. 2 shows the gas analysis device 100 installed in the flue 60. In this example, the flue 60 is formed in a cylindrical tube shape extending in the Z-axis direction. The shape of the flue 60 is not limited to the cylindrical shape. The flue 60 where the gas analysis device 100 is installed has a flue width of 0.5 m or more. In one example, the flue width is 2 m or more and 20 m or less. The flue width can be the same as the analysis target gas 1 The interval between the side walls of the flue in the direction perpendicular to the flow direction.

In the flue 60, holes are formed in each part of the side wall 62a and the side wall 62b facing each other. The side wall 62a and the side wall 62b are side walls on the side of the irradiating unit 10 and the light receiving unit 20, respectively. The tube 30 is inserted into the holes formed in the side wall 62a and the side wall 62b, and the tube 30 is preferably fixed to the flue 60. From the viewpoint of corrosion resistance, the barrel 30 is preferably formed of stainless steel. However, the material of the barrel 30 is not limited. The inner diameter of the tube 30 is as large as the laser light 2 passing through the tube 30 does not interfere with the inner surface of the tube 30, and as small as the cleaning gas 6, 8 flowing in the tube 30 It is better that the flow rate does not become too low. In one example, the inner diameter of the tube 30 is 1 cm or more and 5 cm or less.

The tube 30 protrudes from the side wall 62 a and the side wall 62 b of the flue 60 to the outside of the flue 60. It is preferable that the tube 30 has a flange 36a on the protruding part on the side of the irradiation part 10. Between the flange 36a and the irradiation part 10, it is preferable to provide the irradiation part side connection pipe 30a. A flange 37a is provided to the irradiated part side connecting pipe 30a of this example. In this example, by connecting the flange 36a and the flange 37a, the tube 30 and the irradiation section side connecting tube 30a are connected.

The part of the tube 30 on the side of the light-receiving part 20 also has the same structure as the part on the side of the irradiating part 10. Specifically, it is preferable that the tube 30 has a flange 36b on the protruding portion on the light receiving portion 20 side. Between the flange 36b and the light receiving part 20, it is preferable to provide the light receiving part side connection pipe 30b. In this example, by connecting the flange 36b and the flange 37b, the tube 30 and the light-receiving part-side connecting tube 30b are connected. In addition, since the irradiated part side connects the tube 30a, the flange 37a, the flange 36a, the tube 30, the flange 36b, the flange 37b, and the light receiving part The side connecting tube 30b constitutes a tubular body that connects the irradiating part 10 and the light receiving part 20 in the order of arrangement, so it can be said that these are integrally formed as a tube.

As explained above, by using the flange 36 (36a, 36b) and the flange 37 (37a, 37b), the installation of the tube 30 to the flue 60 and the installation of the irradiating part 10 and the light receiving part 20 through the flange 37 Can be constructed separately. Therefore, the gas analysis device 100 of this example can be easily installed in the flue 60. However, the gas analysis device 100 is not limited to this construction situation, and the tube 30 can also be directly connected to the irradiating part 10 and the light receiving part 20.

The irradiation unit 10 includes a laser element 12, a collimated lens 14, a frame body 16, and a light transmission window 18 on the irradiation unit side. The laser element 12 may be a distributed feedback type (DFB) laser or a vertical cavity surface emitting laser (Vertical Cavity Surface Emitting LASER). The laser element 12 may be a wavelength tunable laser element capable of changing the 2 wavelengths of the output laser light. The collimator lens 14 uses the laser light 2 emitted from the laser element 12 as a parallel light.

The frame 16 is used to house the laser element 12 and the collimating lens 14 inside. A part of the frame 16 is provided with a light transmitting window 18 on the side of the irradiation unit. The laser light 2 passing through the collimator lens 14 travels toward the outside of the housing 16 after passing through the light transmitting window 18 on the irradiation section side. The light-transmitting window 18 on the side of the irradiating part is preferably installed obliquely from a vertical plane with respect to the optical axis of the laser light 2. The irradiation section side connecting pipe 30a is fixed to the frame 16 so as to surround the irradiation section side light transmission window 18. The end of the irradiated part side connecting tube 30a is It is preferable that the light-transmitting window 18 and the frame 16 on the side of the irradiation part are sealed.

The light receiving unit 20 includes a light collecting lens 22, a light receiving element 24, a signal processing unit 25, a frame body 26, and a light receiving unit side light transmitting window 28. The condensing lens 22 is used to condense the laser light 2 after passing through the analysis target gas 1 to the light receiving element 24. The light receiving element 24 is an element that outputs an electrical signal according to the amount of light received. For example, the light receiving element 24 has an optical diode or a photoelectric crystal. The light receiving element 24 preferably outputs a current corresponding to the amount of light received. The signal processing unit 25 preferably receives the current from the light receiving element 24 and converts the received current into a voltage. The signal processing unit 25 performs detection and filtering processing on the converted voltage to generate a signal after noise removal. The signal processing unit 25 preferably uses the signal after noise removal to calculate the concentration of the target substance.

The frame 26 is used to house the collecting lens 22, the light receiving element 24, and the signal processing unit 25 inside. A light-transmitting window 28 on the side of the light receiving section is provided in a part of the frame body 26. The laser light 2 passing through the light-transmitting window 28 on the side of the light receiving unit is incident into the housing 26. The light-transmitting window 28 on the side of the light receiving section is preferably installed obliquely from a vertical plane with respect to the optical axis of the laser light 2. The light-receiving section side connecting pipe 30b is fixed to the frame 26 so as to surround the light-receiving section side light transmission window 28. The end of the light-receiving part-side connecting tube 30b is preferably sealed by the light-receiving part-side light transmission window 28 and the frame 26.

The gas analysis device 100 is provided with an irradiating unit side introduction portion 42 and a light receiving unit side introduction portion 44 for introducing cleaning gases 6 and 8. The irradiated part-side introduction part 42 introduces the cleaning gas 6 into the tube 30 from the end of the tube 30 on the side of the irradiated part 10. On the other hand, the light-receiving part side introduction part 44 is an end of the tube 30 on the light receiving part 20 side, and the cleaning gas 8 is introduced into the tube 30. The cleaning gases 6, 8 can be air or nitrogen.

In this patent specification, the so-called end of the tube 30 on the side of the irradiation section 10 refers to the region of the tube 30 on the side of the irradiation section 10 based on the first hole 32, and particularly refers to: the side wall 62a and the irradiation section The area of the tube 30 between the sections 10 (or the irradiated section side connecting tube 30a). In this patent specification, the so-called end of the tube 30 on the side of the light receiving section 20 refers to the region of the tube 30 located on the side of the light receiving section 20 based on the first hole 32, and in particular refers to the region located on the side wall 62b and The area of the tube 30 between the light-receiving parts 20 (or the light-receiving part-side connecting tube 30b).

The irradiating unit-side introduction unit 42 and the light-receiving unit-side introduction unit 44 may each be a cleaning gas inlet. In this example, the irradiating unit side introduction portion 42 and the light receiving unit side introduction portion 44 are provided outside the flue 60. The irradiating section side introduction section 42 of this example is provided in the irradiating section side connecting tube 30a; the light receiving section side introduction section 44 of this example is provided in the light receiving section side connecting tube 30b. The cleaning gas 6 introduced from the introduction part 42 on the side of the irradiation part is filled in the tube 30 while flowing toward the center of the flue 60 at the same time. Similarly, the cleaning gas 8 introduced from the light-receiving portion-side introduction portion 44 flows toward the center of the flue 60. The cleaning gas 6 and the cleaning gas 8 are discharged from the second hole 34 to the outside of the cylinder 30.

Figure 3 is a side view of the cylinder 30. The second hole 34 is arranged on the downstream side of the analysis target gas 1 so as to face the first hole 32. The second hole 34 is preferably arranged so as to include the outer shape of the first hole 32 when the outer shape of the tube 30 is viewed from the Z-axis direction. The second hole 34, which opens The port area is larger than that of the first hole 32. By forming the first hole 32 and the second hole 34 in this way, the pressure loss of the analyte gas 1 that has passed through the first hole 32 when passing through the second hole 34 can be reduced. Therefore, it is difficult for the analysis target gas 1 to flow into the tube 30 to the side of the irradiation unit 10 and the side of the light receiving unit 20 without passing through the second hole 34.

It is preferable that the first hole 32 and the second hole 34 coincide with the center positions in the X-axis direction, and preferably coincide with the center positions in the Y-axis direction. The length L1 of the first hole 32 in the X-axis direction (long axis direction) is preferably shorter than the length L2 of the second hole 34 in the X-axis direction. The length L1 in the major axis direction of the first hole 32 may be 0.3 m or more and 1 m or less. As an example, the length L1 is 0.5 m. In the gas analysis device 100 of this example, the area of the length L1 in the major axis direction of the first hole 32 is exposed to the analysis target gas 1. And corresponding to the length L1 to determine the measurement optical path length Ls.

The first hole 32 may also be a cut in the surface of the tube 30. When the cylinder 30 is viewed from the Y-axis direction, the cutout thickness D2 of the first hole 32 is, as an example, 1/4 of the outer diameter D1 of the cylinder 30. The cutout thickness D3 of the second hole 34 may be 1/4 of the outer diameter D1 of the cylinder 30. However, the thickness D3 can also be greater than the thickness D2. In this case, the width of the second hole 34 in the Y-axis direction is larger than that of the first hole 32, and the pressure loss when passing through the first hole 32 can be reduced.

Figure 4 is a top view of the cylinder 30. The first hole 32 is preferably formed in a rectangular shape. However, unlike this example, the first hole 32 may be formed in an oval shape. The first hole 32 has a length extending over the barrel 30 It is preferable to have the long axis in the side direction (X-axis direction) and the short axis extending in the Y-axis direction. The second hole 34 is also preferably formed in a rectangular shape or an elliptical shape with a long axis extending in the X-axis direction. Since the long axes of the first hole 32 and the second hole 34 extend toward the longitudinal direction of the tube 30, even when the tube 30 has a small diameter, it is possible to ensure the measurement optical path length Ls that can maintain the accuracy of the analysis sensing.

According to the gas analysis device 100 of this example, the influence of moisture and dust in the analysis target gas 1 on the analysis result can be reduced. In this example, the influence caused by moisture and dust is limited to the area opened by the first hole 32 and the second hole 34. In particular, even in the environment where the width of the flue 60 is large, the gas analysis device 100 cannot be installed without increasing the distance between the irradiating part 10 and the light receiving part 20, the measurement optical path length Ls can be set to be greater than the flue The width of 60 is also short in length, thereby reducing the influence of moisture and dust. Since the influence of moisture and dust is reduced, the gas analyzer 100 can stably analyze the concentration of the target substance.

According to the gas analysis device 100 of this example of this example, the inside of the cylinder 30 is filled with the cleaning gas 6 in the area from the irradiation section 10 to the first hole 32. Similarly, in the area covered from the light receiving unit 20 to the first hole 32, the inside of the cylinder 30 is filled with the cleaning gas 8. Therefore, the analysis target gas 1 does not flow from the first hole 32 and the second hole 34 to the side of the irradiating part 10 and the side of the light-receiving part 20, so that the attenuation of the laser light 2 in the region other than the measurement optical path length Ls can be prevented.

Since the first hole 32 and the second hole 34 are arranged neatly in Since the analysis target gas 1 in the flue 60 is arranged in a flow direction (Z-axis direction), the analysis target gas 1 effectively flows in from the first hole 32 and flows out from the second hole 34. Therefore, in the cylinder 30, in the region corresponding to the measurement optical path length Ls, the analysis target gas 1 flows from the first hole 32 toward the second hole 34. Thereby, in the region corresponding to the measurement optical path length Ls, the cleaning gases 6 and 8 are flowed in the Z-axis direction by the flow of the analysis target gas 1, and then are discharged from the second hole 34. For this reason, it is possible to prevent the cleaning gas 6 and 8 from intruding deeply into the area corresponding to the measurement optical path length Ls.

According to the gas analysis device 100 of this example, the tube 30 is a tube that is disposed between the irradiating part 10 and the light-receiving part 20 so that the laser light 2 passes through the inside, so it is on the side of the irradiating part 10 of the flue 60 The side wall 62a and the side wall 62b on the side of the light receiving unit 20 are supported by both sides. Therefore, compared with the case where the tube 30 is supported by a cantilever, the bending and bending of the tube 30 can be reduced, and the deviation of the optical axis of the laser light 2 can be prevented.

Fig. 5 is a side view of the gas analyzer 100 in the second embodiment of the present invention. Fig. 6 is a cross-sectional view taken along the line AA' of the gas analyzer 100 in the second embodiment of the present invention. The gas analysis device 100 of this example has a cover 50. The other structure is the same as that of the gas analysis device 100 of the first embodiment. The cover 50 is a shield to reduce the influence of dust and moisture. The cover part 50 is preferably formed of stainless steel from the viewpoint of corrosion resistance. However, the material of the barrel 30 is not limited.

The cover part 50 is formed separately from the tube 30. So-called cover part 50 is formed separately from the tube 30, which means that the cover part 50 and the tube 30 are separately provided in the Z-axis direction. In this example, as shown in FIG. 6, the outer side surface of the tube 30 and the inner side surface of the cover portion 50 are separated by a distance H1 in the Z-axis direction. As an example, the separation distance H1 may be greater than the diameter of the tube 30. The cover part 50 is preferably fixed to the barrel 30 through the supporting part 52.

Since the cover part 50 is formed separately from the cylinder 30, the analysis target gas 1 can sufficiently enter the area where the first hole 32 is provided by diffusion, that is, the area corresponding to the measurement optical path length Ls. Therefore, in the area corresponding to the measurement optical path length Ls, it is possible to prevent the concentration of the target substance from being different from the original concentration. On the other hand, dust and moisture are larger and heavier than the molecules of the target substance. For this reason, it is difficult for dust and moisture to sufficiently enter the area where the first hole 32 is provided because it is not easily diffused compared to the molecules of the target substance. Therefore, by providing the cover part 50, the influence of dust and moisture can be reduced, and the concentration of the target substance can be accurately analyzed.

The lower end 54 of the cover part 50 is preferably extended to a lower side than the first hole 32. In this example, the upstream side of the analysis target gas 1 is set as the upper side, and the downstream side of the analysis target gas 1 is set as the lower side. In this example, the position P2 of the lower end 54 of the cover portion 50 is lower than the position P1 of the upper surface of the cutout of the first hole 32. In this way, since the lower end 54 of the cover part 50 extends to a lower side than the first hole 32, it is possible to prevent the dust accumulated on the cover part 50 from falling into the first hole 32.

As shown in Figure 5, the cover part 50 of this example is the first The hole 32 covers the central part in the long axis direction (X-axis direction). The cover part 50 does not cover the ends 38a and 38b of the first hole 32 in the longitudinal direction. Since the cover 50 does not cover the end 38a of the first hole 32, the flow of the analysis target gas 1 is not blocked by the cover 50 at the end 38a of the first hole 32, and the analysis target gas 1 can be secured. Of the flow. Therefore, the cleaning gas 6 receives the flow of the analysis target gas 1 near the end 38 a of the first hole 32 and flows in the Z-axis direction, and then is discharged from the second hole 34. For this reason, the cleaning gas 6 can be prevented from intruding deeply into the area corresponding to the measurement optical path length Ls. Similarly, it is also possible to prevent the cleaning gas 8 from intruding deeply into the area corresponding to the measurement optical path length Ls.

Fig. 7 is a side view showing a modification of the gas analyzer 100 in the second embodiment. In the gas analysis device 100 of this example, the cover part 50 covers the entire first hole 32. In this patent specification, the so-called cover part 50 covers the entire first hole 32, which means that the length of the cover part 50 in the X-axis direction is longer than the length of the first hole 32 in the X-axis direction It is long, and the length of the cover part 50 in the Y-axis direction is longer than the length of the first hole 32 in the Y-axis direction. The cover part 50 is formed with a hole 56 through which the analysis target gas 1 passes. Except for the difference of the cover part 50, the other structure is the same as that of the gas analyzer 100 shown in FIG.

The hole portion 56 is preferably formed in the center portion of the cover portion 50 in the X-axis direction. The size of the hole 56 in this example is smaller than the width of the first hole 32 in the Y-axis direction. The size of the hole 56 is not It is determined by the way that dust and moisture block the holes.

According to the gas analysis device 100 of this example, the cover part 50 that functions as a shield is larger than the first hole 32, and the cover part 50 covers the entire first hole 32. Therefore, the influence of moisture and dust can be further reduced. With the hole portion 56, the flow of the analysis target gas 1 from the first hole 32 to the second hole 34 can be ensured, so that the cleaning gases 6 and 8 can be prevented from intruding deeply into the area where the first hole 32 is formed.

In the gas analysis device 100 of this example, as shown in FIG. 5, the cover portion 50 may cover the central portion of the first hole 32 in the longitudinal direction without placing the first hole 32 in the long axis. It is preferable that the end 38 in the axial direction is covered, and the hole 56 is provided at the same time.

Fig. 8 is a side view showing another modification of the gas analysis device 100 in the second embodiment. In the gas analysis device 100 of this example, a hole portion 56a, a hole portion 56b, and a hole portion 56c are formed in the cover portion 50. The other structure is the same as the example shown in Figure 7. Among the plurality of hole portions 56, the hole portion 56 b is formed in the center portion of the cover portion 50 in the X-axis direction. The hole 56a and the hole 56c are preferably formed at positions facing the end 38a and the end 38b of the first hole 32 in the longitudinal direction. However, the number and positions of the plurality of holes formed in the cover part 50 are not limited. In the cover portion 50, the hole portion 56a and the hole portion 56c may be formed instead of the hole portion 56b.

In the cover part 50, by forming a plurality of holes 56, it is easier to prevent the cleaning gas 6, 8 from penetrating deeply into the area where the first hole 32 is formed, compared to the case where the hole 56 is one. In particular, with the hole 56a The hole portion 56c is formed at a position facing the end portions 38a, 38b of the first hole 32 in the longitudinal direction, and can easily prevent the cleaning gas 6, 8 from penetrating deeply into the area corresponding to the measurement optical path length Ls.

In the end 38a of the first hole 32, the flow of the analysis target gas 1 can be ensured by the cover part 50 not blocking the flow of the analysis target gas 1. Therefore, the cleaning gas 6 receives the flow of the analysis target gas 1 after passing through the hole portion 56 a and flows in the Z-axis direction, and then is discharged from the second hole 34. For this reason, the cleaning gas 6 does not penetrate deeply into the area corresponding to the measurement optical path length Ls. Similarly, the cleaning gas 8 will not penetrate deeply into the area corresponding to the measurement optical path length Ls.

Fig. 9 is a side view showing another modification of the gas analyzer 100 in the second embodiment. In the gas analysis device 100 of this example, the cover part 50 is divided into a plurality of cover parts 50a and 50b. The plurality of cover parts 50a and cover parts 50b are preferably arranged along the X-axis direction with a predetermined gap. The other structure is the same as the example shown in Figure 5. The gap between a plurality of adjacent cover portions 50a and 50b has the same function as the hole portion 56b without blocking the flow of the analysis target gas 1. Therefore, this modification can also prevent the cleaning gas 6 and the cleaning gas 8 from penetrating deeply into the area corresponding to the measurement optical path length. In this example, the cover part 50 is divided into two cover parts 50a and 50b, but the cover part 50 may be divided into three or more cover parts.

Although the embodiments have been used to describe the present invention above, the technical scope of the present invention is not limited to the scope described in the above embodiments. Surrounding. Each embodiment and each modification example can be combined with each other. In the above-mentioned embodiment, it is obvious that various changes or improvements can be added to the industry. From the description of the scope of patent application, it is clear that the form to which the various changes or improvements are added is also included in the technical scope of the present invention.

1‧‧‧Analyzing target gas

2‧‧‧Laser light

6‧‧‧Cleaning gas

8‧‧‧Cleaning gas

10‧‧‧ Irradiation Department

20‧‧‧Light receiving part

30‧‧‧tube

32‧‧‧The first hole

34‧‧‧The second hole

60‧‧‧ Flue

100‧‧‧Gas analysis device

Claims (10)

A gas analysis device is characterized by comprising: an irradiating part that irradiates laser light to an analysis target gas flowing in a flue, and a light-receiving part that is arranged opposite to the irradiating part with the flue interposed therebetween, and The laser light that has passed through the analysis target gas and the integrated tube are arranged between the irradiating part and the light receiving part so that the laser light passes through the inside, and is formed in the flue to face the The first hole on the upstream side of the analysis target gas, the second hole facing the downstream side of the analysis target gas, and the cover part are separated from the cylinder and partially cover the first hole. The gas analysis device according to the first item of the scope of patent application, which is provided with: an irradiated part-side introduction part for introducing cleaning gas into the tube from an end of the irradiated part side of the cylinder, and a light-receiving part-side introduction part , The cleaning gas is introduced into the tube from the end of the tube on the light receiving part side. The gas analysis device according to claim 1, wherein the second hole is arranged on the downstream side of the analysis target gas so as to face the first hole, and its opening area is larger than that of the first hole. Bigger. The gas analysis device according to claim 1, wherein the first hole and the second hole have a long axis extending in the longitudinal direction of the cylinder. The gas analysis device described in claim 1, wherein the cover part covers the central part of the first hole in the long axis direction, and does not cover the first hole in the long axis direction. The end of the tube is covered, and the first hole has a long axis extending in the longitudinal direction of the tube. The gas analysis device according to claim 1, wherein the cover is formed with a hole through which the analysis target gas passes. The gas analysis device described in claim 6, wherein the cover part covers the whole of the first hole, and the hole part is formed. The gas analysis device described in claim 6, wherein the cover portion is formed with a plurality of the holes. The gas analysis device according to the first item of the scope of patent application, wherein the cover part is divided into a plurality of pieces. The gas analysis device described in claim 1, wherein the lower end of the cover portion extends to a lower side than the first hole.

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