TW201802452A - Gas analytical device Including an illumination part, a light receiving part and an integrated tube - Google Patents

Abstract

The issue of the present invention is to decrease the effects caused by dusts or moisture in gases to be analyzed. The solution of the present invention is to provide a gas analytical device which comprises an illumination part, a light receiving part and an integrated tube. The illumination part is configured to illuminate the gas to be analyzed in an air channel with laser light. The light receiving part is disposed face-to-face correspondingly to the illumination part in a manner that they are separated by the air channel, and configured to receive the laser light passed through the gas to be analyzed. The integrated tube is disposed between the illumination part and the light receiving part so that the laser light may pass therethrough. In addition, the tube defines a first hole facing an upper stream of the gas to be analyzed in the air channel and a second hole facing a lower stream of the gas to be analyzed in the air channel.

Description

Gas analysis device

The present invention relates to a gas analysis device.

Conventionally, a laser-type gas analyzer is known. The gas analysis device includes an irradiating unit that irradiates laser light to the analysis target gas, and a light receiving unit that receives laser light rays passing through the analysis target gas. The gas analyzer analyzes the absorption spectrum based on the amount of light received in the light receiving section. The gas analysis device analyzes the concentration of a target substance in a target gas based on an absorption spectrum (for example, refer to Patent Document 1).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2009-270917

In the laser-type gas analysis device, when the gas to be analyzed contains moisture or dust, the laser light is scattered or absorbed by the moisture or dust. Depending on the amount of moisture or dust, A situation where the amount of received laser light in the light-receiving section makes it difficult to measure the concentration of the target substance.

As in the present invention, the gas analysis device preferably includes: an irradiating section, a light receiving section, and a tube; the irradiating section is preferably irradiated with laser light to the analysis target gas flowing in the flue; It is better to face the irradiating part through the flue. The light receiving part is better 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 It is preferable that the tube is a body formed between the light receiving portion and the first hole and the second hole are formed in the tube in the flue. The first hole is preferably 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 preferably includes an irradiating section side introducing section and a light receiving section side introducing section; the irradiating section side introducing section preferably introduces cleaning gas from the end of the irradiated section side of the cartridge into the cylinder; It is preferable that the cleaning gas is introduced into the cylinder from the end portion on the light receiving portion side of the cylinder.

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

It is preferable that the first hole and the second hole have a long axis; the long axis is preferably extended toward the long side of the cylinder.

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

The cover part preferably covers the central part of the first hole in the long axis direction; the cover part preferably does not cover the end of the first hole in the long axis direction; the first hole is It has a long axis extending toward the long side of the tube.

It is preferable that the hole portion is formed in the cover portion; it is preferable that the hole passes the analysis target gas.

The cover portion is preferably formed by covering the entirety of the first hole; the hole portion is preferably formed by the cover portion.

Preferably, a plurality of holes are formed in the cover portion.

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

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

It is to be noted that the summary of the content of the invention described above is not necessarily all of the essential features of the invention. In addition, the subcombination of these feature groups is of course an invention.

1‧‧‧ analysis target gas

2‧‧‧ laser light

6‧‧‧ cleaning gas

8‧‧‧ cleaning gas

10‧‧‧ Irradiation Department

12‧‧‧laser element

14‧‧‧ Collimating lens

16‧‧‧Frame

18‧‧‧ side light transmission window

20‧‧‧Light receiving section

22‧‧‧ collection lens

24‧‧‧ light receiving element

25‧‧‧Signal Processing Department

26‧‧‧Frame

28‧‧‧Side light transmission window

30‧‧‧ tube

30a‧‧‧ side connection tube

30b‧‧‧ side connecting tube

32‧‧‧ 1st hole

34‧‧‧ 2nd hole

36‧‧‧ flange

37‧‧‧ flange

38‧‧‧ tip

42‧‧‧Irradiation section side introduction section

44‧‧‧ Light-receiving part side introduction part

50‧‧‧ Cover section

52‧‧‧ support

54‧‧‧ bottom

56‧‧‧ Hole

60‧‧‧chimney

62‧‧‧ sidewall

100‧‧‧Gas analysis device

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

Fig. 2 is a sectional view of the gas analysis device 100 in the first embodiment of the present invention.

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

FIG. 4 is a top view of the cartridge 30.

Fig. 5 is a side view of a gas analysis device 100 according to a second embodiment of the present invention.

Fig. 6 is a cross-sectional view taken along line AA 'of the gas analysis device 100 according to 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 analysis device 100 in the second embodiment.

[Embodiment for Implementing the Invention]

Hereinafter, the present invention will be described using embodiments of the invention. However, the following embodiments are not intended to limit the invention described in the scope of patent application. It should be noted that all combinations of the features described in the embodiments are not necessarily required for solving the invention.

In this patent specification, technical matters are described using a rectangular coordinate system of the X axis, the Y axis, and the Z axis. The rectangular coordinate system is only used to specify the relative positions of the constituent elements, not to limit the specific direction. For example, the Z axis is not meant to be used to define the height direction relative to the ground. The + Z-axis direction and the -Z-axis direction are mutually opposite directions. When the positive and negative are not recorded, but the Z-axis direction is recorded, it is Refers to directions parallel to the + Z and -Z axes.

FIG. 1 is a perspective view showing the outline of a gas analysis device 100 according to the first embodiment of the present invention. The gas analyzer 100 analyzes 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 a gas discharged from a boiler or a combustion furnace. Boilers or burners can be coal, heavy oil, or garbage. However, here, the flue 60 is not limited to a gas flow path. The flue 60 in this patent specification may be a machine containing an internal space in which the analysis target gas 1 can flow, or a container, a chimney, an exhaust duct, a denitration device, a chemical plant equipment, a steel plant equipment And various equipment such as heating furnaces.

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

The gas analysis device 100 of this example includes a cylinder 30 that is disposed between the irradiation unit 10 and the light receiving unit 20. The integrated tube 30 refers to a tubular body that connects the irradiation unit 10 and the light receiving unit 20. The integrated tube 30 is not required between the irradiation section 10 and the light receiving section 20. It is divided and disconnected, and it is comprised by joining several cylinders. The tube 30 is arranged so that the laser light 2 passes through the inside. The cylinder 30 of this example is arranged so that its longitudinal direction is 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, it is preferable that the laser light 2 passes near the central axis of the tube 30.

A first hole 32 and a second hole 34 are formed in the tube wall of the cylinder 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 flows out from the second hole 34. Therefore, the space region sandwiched by the first hole 32 and the second hole 34 is exposed to the analysis target gas environment. In the space region sandwiched between 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 located in the X-axis direction of the cylinder 30 toward the center.

The gas analyzer 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 a target substance contained in the analysis target gas 1 from an absorption spectrum. The target substance may be a gas component 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 may be various gases such as carbonized 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 amount of attenuation of the laser light 2 at a specific wavelength. Specifically, according to Lambert-Beer's law, the amount of 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 is present. The expression of Lambert-Bill is shown in [Equation 1]. In this example, the measurement optical path length Ls is defined by the length located in the X-axis direction of the first hole 32. Since the processing performed by the gas analysis device 100 is the same as that of the conventional laser gas analysis device, detailed description is omitted.

[Equation 1] I (L) = I (O). exp [-ks. Ns. Ls]

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

I (O) is the amount of light (light emission).

Ks is the gas constant.

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

Ls is the measurement optical path length.

FIG. 2 is a cross-sectional view of the gas analysis device 100 according to the first embodiment of the present invention. FIG. 2 shows the gas analysis device 100 in a state where it is installed in the flue 60. In this example, the flue 60 is formed into a cylindrical tube shape extending in the Z-axis direction. The shape of the flue 60 is not limited to a cylindrical shape. The flue 60 to which 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 that of the analysis target gas 1. Space between the side walls of the flue in the direction perpendicular to the direction of flow.

In the flue 60, a hole is formed in each portion of the side wall 62a and the side wall 62b facing each other. The side walls 62a and 62b are the side walls of the irradiated portion 10 side and the light receiving portion 20 side, respectively. The tube 30 is inserted into a hole formed in the side wall 62 a and the side wall 62 b. The tube 30 is preferably fixed to the flue 60. The barrel 30 is preferably formed of stainless steel from the viewpoint of corrosion resistance. However, the material of the cylinder 30 is not limited. The inner diameter of the cylinder 30 is as large as the laser light 2 passing through the cylinder 30 does not interfere with the inner side of the cylinder 30, and as small as the cleaning gas 6, 8 flowing in the cylinder 30 It is preferable that the flow velocity 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 cylinder 30 protrudes from the side wall 62 a and the side wall 62 b of the flue 60 outside the flue 60. The barrel 30 is preferably provided with a flange 36a at a protruding portion on the side of the irradiation section 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 on the irradiation-unit-side connection pipe 30a of this example. In this example, by connecting the flange 36a and the flange 37a, the tube 30 and the irradiation-unit-side connection tube 30a are communicated.

The portion of the tube 30 on the light receiving portion 20 side also has the same configuration as that of the portion on the irradiation portion 10 side. Specifically, it is preferable that the tube 30 is provided with a flange 36 b on a protruding portion on the light receiving unit 20 side. Between the flange 36b and the light receiving unit 20, it is preferable to provide a light receiving unit side connecting pipe 30b. In this example, the tube 30 and the light-receiving-part-side connecting tube 30b are communicated by connecting the flange 36b and the flange 37b. In addition, the irradiating section-side connecting tube 30a, flange 37a, flange 36a, tube 30, flange 36b, flange 37b, and light receiving section Since the side connection tubes 30b constitute a tubular body that connects the irradiation section 10 and the light receiving section 20 in the order of arrangement, it can be said that these are integrally formed tubes.

As described above, by using the flanges 36 (36a, 36b) and the flanges 37 (37a, 37b), the mounting of the cylinder 30 to the flue 60 and the mounting of the irradiation section 10 and the light receiving section 20 through the flange 37 are performed. 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 such a construction situation, and the tube 30 may be directly connected to the irradiation section 10 and the light receiving section 20.

The irradiation unit 10 includes a laser element 12, a collimated lens 14, a frame 16, and a light transmitting window 18 on the irradiation unit side. The laser element 12 may be a distributed feedback (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 two wavelengths of laser light output. The collimator lens 14 uses the laser light 2 emitted from the laser element 12 as parallel light.

The frame 16 is used to house the laser element 12 and the collimator lens 14 inside. A part of the frame body 16 is provided with an irradiation unit side light transmission window 18. The laser light 2 that has passed through the collimator lens 14 passes through the light-transmitting window 18 on the side of the irradiation unit and advances toward the outside of the housing 16. The irradiation unit side light transmission window 18 is preferably provided obliquely from a vertical plane with respect to the optical axis of the laser light 2. The irradiation unit-side connecting pipe 30 a is fixed to the frame body 16 so as to surround the irradiation unit-side light transmitting window 18. The end of the irradiation section-side connecting pipe 30a is formed by The light-transmitting window 18 and the frame 16 on the side of the irradiation unit are preferably sealed.

The light receiving unit 20 includes a light collecting lens 22, a light receiving element 24, a signal processing unit 25, a frame 26, and a light receiving unit side light transmission window 28. The light collecting lens 22 collects the laser light 2 that has passed through the analysis target gas 1 onto the light receiving element 24. The light receiving element 24 is an element that outputs an electric signal in accordance with the amount of light received. For example, the light receiving element 24 includes a photodiode or a photo-crystal. The light receiving element 24 preferably outputs a current corresponding to the amount of light received. The signal processing unit 25 preferably receives a 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 calculates the concentration of the target substance using the noise-removed signal.

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

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

In this patent specification, the end portion on the side of the irradiated portion 10 of the tube 30 refers to the area of the tube 30 on the side of the irradiated portion 10 based on the first hole 32, and particularly refers to the side wall 62a and the irradiated portion. The area of the tube 30 (or the irradiation-part-side connection tube 30a) between the sections 10. In this patent specification, the end portion of the tube 30 on the light receiving portion 20 side refers to a region of the tube 30 located on the light receiving portion 20 side with reference to the first hole 32, and particularly refers to the positions of the side walls 62b and The area of the tube 30 (or the light-receiving-unit-side connecting tube 30b) between the light-receiving sections 20.

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

FIG. 3 is a side view of the cylinder 30. The second hole 34 is disposed 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 that the outer shape of the cylinder 30 is viewed from the Z-axis direction so as to include the outer shape of the first hole 32. 2nd hole 34, which opens The mouth area is larger than the first hole 32. By forming the first hole 32 and the second hole 34 in this manner, the pressure loss of the analysis target 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 irradiating section 10 and the light receiving section 20 in the cylinder 30 without passing through the second hole 34.

It is preferable that the first hole 32 and the second hole 34 are aligned with each other in the center position in the X-axis direction, and the center positions in the Y-axis direction are preferably aligned. 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 long 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 long axis direction of the first hole 32 is exposed to the analysis target gas 1. The measurement optical path length Ls is determined corresponding to the length L1.

The first hole 32 may be a cutout on the surface of the cylinder 30. When the tube 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 tube 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 may be larger 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.

FIG. 4 is a top view of the cartridge 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 to the barrel 30 It is preferable that the long axis in the lateral 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 or elliptical shape having a long axis extending in the X-axis direction. By extending the long axes of the first hole 32 and the second hole 34 toward the long side of the tube 30, even when the diameter of the tube 30 is small, the measurement optical path length Ls that can maintain the accuracy of the analysis and induction can be ensured.

According to the gas analysis device 100 of this example, it is possible to reduce the influence on the analysis result caused by the moisture and dust existing in the analysis target gas 1. In this example, the influence caused by water vapor 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 measurement optical path length Ls can be set to be larger than the flue in an environment where the gas analysis device 100 cannot be installed without increasing the distance between the irradiation section 10 and the light receiving section 20. The width of 60 is also a short length, which can reduce the influence of moisture and dust. Since the influence of moisture and dust is reduced, the gas analysis device 100 can stably analyze the concentration of the target substance.

According to the gas analysis device 100 of this example, in the area extending from the irradiation section 10 to the first hole 32, the inside of the cylinder 30 is filled with the cleaning gas 6. Similarly, in a region extending from the light receiving section 20 to the first hole 32, the inside of the cylinder 30 is filled with the cleaning gas 8. Therefore, since the analysis target gas 1 does not flow from the first hole 32 and the second hole 34 to the irradiation section 10 side and the light receiving section 20 side, it is possible to prevent the attenuation of the laser light 2 located in a region other than the measurement optical path length Ls.

Since the first hole 32 and the second hole 34 are arranged neatly Since the analysis target gas 1 in the flue 60 is arranged in the 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 tube 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 area corresponding to the measurement optical path length Ls, the cleaning gases 6 and 8 are flowed in the Z-axis direction upon receiving the flow of the analysis target gas 1, and then discharged from the second hole 34. For this reason, it is possible to prevent the cleaning gas 6, 8 from penetrating deeply into the area corresponding to the measurement optical path length Ls.

According to the gas analysis device 100 of this example, the cylinder 30 is a cylinder arranged between the irradiating unit 10 and the light receiving unit 20 so that the laser light 2 passes through the inside. The side wall 62a and the side wall 62b on the side of the light receiving unit 20 are supported on both sides so as to be supported. Therefore, compared with the case where the barrel 30 is supported by the cantilever, the bending and bending of the barrel 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 a gas analysis device 100 according to a second embodiment of the present invention. Fig. 6 is a cross-sectional view taken along line AA 'of the gas analysis device 100 according to the second embodiment of the present invention. The gas analysis device 100 of this example includes a cover portion 50. The other structures are the same as those of the gas analysis device 100 according to the first embodiment. The cover portion 50 is a cover for reducing the influence of dust and moisture. The cover portion 50 is preferably formed of stainless steel from the viewpoint of corrosion resistance. However, the material of the cylinder 30 is not limited.

The cover portion 50 is formed separately from the tube 30. So-called cover 50 is formed separately from the cylinder 30 and means that the cover portion 50 and the cylinder 30 are provided separately from each other in the Z-axis direction. In this example, as shown in FIG. 6, the outer side surface of the cylinder 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 equal to or greater than the diameter of the cylinder 30. The cover portion 50 is preferably fixed to the barrel 30 with the intermediate support portion 52 interposed therebetween.

Since the cover portion 50 is formed separately from the tube 30, the analysis target gas 1 can sufficiently enter the area provided with the first hole 32 by diffusion, that is, the area corresponding to the measurement optical path length Ls. Therefore, in a region 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 in particle size than the molecules of the target substance. For this reason, it is difficult for dust and water vapor to sufficiently enter the area where the first hole 32 is provided because the diffusion is not as easy as for the molecules of the target substance. Therefore, by providing the cover portion 50, the influence of dust and water vapor can be reduced, and the concentration of the target substance can be accurately analyzed.

The lower end 54 of the cover portion 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 made upward, and the downstream side of the analysis target gas 1 is made downward. 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, by lowering the lower end 54 of the cover portion 50 to a lower side than the first hole 32, it is possible to prevent dust accumulated on the cover portion 50 from falling into the first hole 32.

As shown in FIG. 5, the cover portion 50 of this example is the first The center of the hole 32 in the long axis direction (X-axis direction) is covered. The cover portion 50 does not cover the end portions 38 a and 38 b of the first hole 32 in the longitudinal direction. Since the cover portion 50 does not cover the end portion 38a of the first hole 32, the flow of the analysis target gas 1 at the end portion 38a of the first hole 32 is not blocked by the cover portion 50, and the analysis target gas 1 can be secured Flow. Therefore, the cleaning gas 6 is caused to flow in the Z-axis direction by the flow of the analysis target gas 1 near the end portion 38 a of the first hole 32, and is then discharged from the second hole 34. For this reason, the cleaning gas 6 can be prevented from penetrating deeply into the area corresponding to the measurement optical path length Ls. Similarly, the cleaning gas 8 can be prevented from penetrating deeply into the area corresponding to the measurement optical path length Ls.

Fig. 7 is a side view showing a modification of the gas analysis device 100 in the second embodiment. In the gas analysis device 100 of this example, the cover portion 50 covers the entire first hole 32. In this patent specification, the cover portion 50 covers the entirety of the first hole 32, which means that the length in the X-axis direction of the cover portion 50 is greater than the length in the X-axis direction of the first hole 32. The length of the cover portion 50 in the Y-axis direction is longer than the length of the first hole 32 in the Y-axis direction. A hole portion 56 through which the analysis target gas 1 passes is formed in the cover portion 50. The structure is the same as that of the gas analysis device 100 shown in FIG. 5 except for the difference in the cover portion 50.

The hole portion 56 is preferably formed in a central portion of the cover portion 50 in the X-axis direction. The size of the hole portion 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 It is determined by the way that dust and water block the holes.

According to the gas analysis device 100 of this example, the cover portion 50 functioning as a shield is larger than the first hole 32, and the cover portion 50 covers the entirety of the first hole 32. Therefore, the influence of moisture and dust can be further reduced. Since the flow of the analysis target gas 1 from the first hole 32 to the second hole 34 is ensured by the hole portion 56, it is possible to prevent the cleaning gas 6 and 8 from penetrating 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 center portion of the first hole 32 in the long axis direction, instead of covering the first hole 32 in the long direction. The end portion 38 in the axial direction is formed so as to cover it, and it is also preferable to provide a hole portion 56 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 FIG. Among the plurality of hole portions 56, the hole portion 56 b is formed at a central portion of the cover portion 50 in the X-axis direction. The hole portion 56a and the hole portion 56c are preferably formed at positions facing the end portion 38a and the end portion 38b of the first hole 32 in the major axis direction. However, the number and positions of the plurality of hole portions formed in the cover portion 50 are not limited. The cover part 50 may be formed with the hole part 56a and the hole part 56c, and the hole part 56b may not be formed.

In the cover portion 50, a plurality of holes 56 are formed. Compared with the case where there is only one hole portion 56, it is easy to prevent the cleaning gas 6, 8 from penetrating deeply into the area where the first holes 32 are formed. In particular, through the hole portion 56a The hole portion 56c is formed at a position facing the end portions 38a and 38b of the first hole 32 in the major axis direction, and it is easy to prevent the cleaning gas 6 and 8 from penetrating deeply into the area corresponding to the measurement optical path length Ls.

In the end portion 38 a of the first hole 32, the flow of the analysis target gas 1 can be ensured because the cover portion 50 does not block the flow of the analysis target gas 1. Therefore, the cleaning gas 6 is caused to flow in the Z-axis direction by the flow of the analysis target gas 1 after passing through the hole portion 56 a, and is then 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 does not penetrate deeply into the area corresponding to the measurement optical path length Ls.

Fig. 9 is a side view showing another modified example of the gas analysis device 100 in the second embodiment. In the gas analysis device 100 of this example, the cover portion 50 is divided into a plurality of cover portions 50a and 50b. The plurality of cover portions 50a and the cover portions 50b are preferably arranged along the X-axis direction with a gap determined in advance. The other structure is the same as the example shown in FIG. 5. The gaps between the adjacent cover portions 50 a and 50 b have the same function as the hole portion 56 b without blocking the flow of the analysis target gas 1. Therefore, according to this modification, it is also possible to 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, although the cover portion 50 is divided into two cover portions 50a and 50b, the cover portion 50 may be divided into three or more cover portions.

As mentioned above, although this invention was demonstrated using embodiment, the technical scope of this invention is not limited to the range described in the said embodiment. Around. Each embodiment and each modification can be mutually combined. In the embodiment described above, it is obvious that various changes or improvements can be added to the industry. It is clear from the description of the scope of the patent application that the various modifications or improvements are also included in the technical scope of the present invention.

1‧‧‧ analysis target gas

2‧‧‧ laser light

6‧‧‧ cleaning gas

8‧‧‧ cleaning gas

10‧‧‧ Irradiation Department

20‧‧‧Light receiving section

30‧‧‧ tube

32‧‧‧ 1st hole

34‧‧‧ 2nd hole

60‧‧‧chimney

100‧‧‧Gas analysis device

Claims (11)

A gas analysis device comprising: an irradiating unit for irradiating laser light and a light receiving unit for an analysis target gas flowing in a flue; and a light receiving unit arranged to face the irradiating unit through the flue and The integrated tube receiving the laser light passing through the analysis target gas and the integrated tube are arranged between the irradiating section and the light receiving section so that the laser light passes through the inside, and are formed in the flue with a facing The first hole on the upstream side of the analysis target gas and the second hole facing the downstream side of the analysis target gas. The gas analysis device according to item 1 of the scope of patent application, further comprising: an irradiating section side introduction section for introducing a cleaning gas into the cylinder from an end portion of the irradiating section side of the cylinder, and a light receiving section side introduction section The cleaning gas is introduced into the cylinder from an end portion on the light receiving portion side of the cylinder. The gas analysis device according to item 1 of the scope of patent application, wherein the second hole is disposed on the downstream side of the analysis target gas so as to face the first hole, and has an opening area larger than that of the first hole. Bigger. The gas analysis device according to item 1 of the scope of patent application, wherein: The first hole and the second hole have a long axis extending in a longitudinal direction of the tube. The gas analysis device according to item 1 of the scope of patent application, further comprising a cover portion which is formed separately from the tube and covers the first hole locally. The gas analysis device according to item 5 of the scope of patent application, wherein the cover portion covers the central portion of the first hole in the long axis direction, and does not cover the first hole in the long axis direction. An end portion of the first hole is covered, and the first hole has a long axis extending in a longitudinal direction of the tube. The gas analysis device according to claim 5, wherein a hole portion is formed in the cover portion to pass the analysis target gas. The gas analysis device according to item 7 of the scope of patent application, wherein the cover portion covers the entire first hole and is formed with the hole portion. The gas analysis device according to claim 7 in the patent application scope, wherein the cover portion is formed with a plurality of the hole portions. The gas analysis device according to item 5 of the patent application scope, which In the above, the cover portion is divided into a plurality of pieces. The gas analysis device according to claim 5 in which the lower end of the cover portion extends to a lower side than the first hole.