JP6248850B2 - Fluid sample measuring device - Google Patents

Description

  The present invention relates to a fluid sample measurement device that irradiates a fluid sample with excitation light and measures scattered light and luminescence from the fluid sample.

One of the apparatuses used for specifying and quantifying components contained in a fluid sample such as a gas sample and a liquid sample is a Raman spectroscopic analyzer.
In the Raman spectroscopic measurement, a sample is irradiated with excitation light, and the Raman spectrum is created by measuring the Raman scattered light (Raman scattered light) by the sample. In the Raman spectrum, a Stokes line appears on the longer wavelength side than the wavelength of the excitation light, and an anti-Stokes line appears on the shorter wavelength side. The energy corresponding to the difference between the wavelength of the excitation light and the wavelength of the Stokes line (or anti-Stokes line) reflects the energy of the natural vibration of the molecule. Therefore, the substance contained in the sample can be specified from the magnitude of this energy. Further, the substance corresponding to the Stokes line or the anti-Stokes line can be quantified from the intensity of the Stokes line or the anti-Stokes line appearing in the Raman scattering spectrum.

  In Patent Document 1, the gas to be measured is irradiated with excitation light on the fuel gas (measured gas) flowing in the branch pipe provided in the middle of the pipe (main pipe) through which the fuel gas supplied to the power generation gas turbine flows. Describes an apparatus for measuring the concentration of each component in a fuel gas by measuring the Raman scattered light from the fuel gas. In this apparatus, excitation light is incident in a direction orthogonal to the flow of the gas to be measured through a window provided on the wall surface of the branch pipe, and Raman scattered light scattered by the gas to be measured is measured. At this time, if light that passes through the gas to be measured and is reflected by the wall surface of the branch pipe is detected, noise in the Raman spectrum is generated. Therefore, laser light containment means having a space with irregularities formed inside is arranged on the wall surface of the branch pipe located on the optical path of the laser light, and the excitation light transmitted through the gas to be measured is diffused and absorbed therein. This reduces noise.

Japanese Patent No. 4160866

In a device that measures gas taken from the main pipe into the branch pipe, the larger the branch pipe diameter, the longer it takes for the gas to be measured taken from the main pipe to reach the branch pipe. Sexuality gets worse. For this reason, the diameter of the branch pipe is usually made as small as possible within the range in which the measurement optical system can be arranged to improve the real-time property of the measurement. However, if a space having a sufficient volume for confining the laser beam inside is provided on the wall surface of the branch pipe as described above, the internal space of the laser beam containment means with respect to the size of the gas circulation space inside the branch pipe And the gas to be measured flowing through the branch pipe tends to stay inside the scattering preventing means. As a result, the gas that reaches the measurement position immediately after being taken into the branch pipe from the main pipe and the gas that stays inside the anti-scattering means after being taken into the branch pipe from the main pipe are mixed in the measurement position and the measurement accuracy is increased. Sex is lost.
Here, the case of measuring Raman scattered light from a gas sample taken from a main pipe into a branch pipe has been described as an example, but in an apparatus for measuring a gas sample flowing through the main pipe as it is, scattering prevention means is provided on the wall surface of the main pipe. The same problem arises when the is provided. The same problem occurs when the sample is a liquid or when light emission from the sample is measured.

  The problem to be solved by the present invention is to reduce noise light without impairing the accuracy of measurement in a fluid sample measurement device that irradiates a fluid sample with excitation light and measures scattered light and luminescence from the fluid sample. That is.

In order to solve the above problems, a fluid sample measuring device according to the present invention comprises:
a) a cylindrical part through which a fluid sample flows;
b) a window portion provided on the side wall surface of the cylindrical portion;
c) an excitation optical system that irradiates the measurement point inside the cylindrical portion with excitation light through the window;
d) a detection optical system for detecting measurement light from the fluid sample at the measurement point through the window;
e) a reflecting portion having a reflecting surface having a normal line that is non-parallel to the optical axis of the excitation light, provided in a region including a position on the optical axis of the excitation light on the side wall surface of the cylindrical portion;
It is characterized by providing.

The cylindrical portion may have any shape as long as the fluid sample can flow therethrough, and a cylindrical or rectangular tube can be used.
In the fluid sample measuring device according to the present invention, for example, the relative positional relationship between the cylindrical portion and the excitation optical system is set so that the optical axis of the excitation light is shifted from the direction perpendicular to the side wall surface of the cylindrical portion. Can be configured. In this case, the side wall of the cylindrical portion itself becomes the reflecting surface.
In addition, the optical axis of the excitation light is set in a direction perpendicular to the side wall surface of the cylindrical portion, and a reflection surface having a normal line non-parallel to the optical axis of the excitation light is provided at the position of the side wall surface irradiated with the excitation light. It can also comprise by attaching the member which has.

  In the fluid sample measuring device according to the present invention, the normal of the side wall surface of the cylindrical portion located on the optical path of the excitation light and the optical axis of the excitation light are non-parallel, so that the cylindrical portion is transmitted through the fluid sample. The light that is specularly reflected by the side wall surface of the tube does not go to the window portion of the cylindrical portion. Therefore, this reflected light is not introduced into the detection optical system through the window. Moreover, in the fluid sample measuring device according to the present invention, the flow space of the fluid sample is only inside the cylindrical portion and the fluid sample does not stay, so that accurate measurement can be performed.

  In the fluid sample measurement device according to the present invention, it is possible to prevent the excitation light that is specularly reflected by the wall surface of the cylindrical portion from being introduced into the detection optical system. However, when the ratio of the excitation light diffusely reflected by the wall surface of the cylindrical portion is high, a part of the excitation light diffused and reflected is introduced into the detection optical system through the window portion.

Therefore, it is preferable that the reflective surface is black-plated. Thereby, a light absorptivity can be raised and the light quantity of the excitation light which diffusely reflects can be suppressed.
Or it is preferable that the said reflective surface is smoothed. Thereby, more excitation light can be specularly reflected in a direction in which the window portion is not positioned, and noise light can be suppressed. The smoothing processed reflecting surface, for example, a reflecting surface of which it can be realized by machining Ra (arithmetic mean roughness) ≦ 3.2μ m.

  Further, when the reflecting surface is subjected to a smoothing process by machining or the like, a linear or arcuate processing mark is usually formed. In the fluid sample measurement device according to the present invention, the direction of such a processing mark includes the optical axis of the excitation light incident on the reflection surface and the surface including the optical axis of the excitation light specularly reflected by the reflection surface (excitation surface of the excitation light). ) In parallel. There are fine irregularities in the direction perpendicular to the direction in which the processing marks extend, and the excitation light diffused and reflected spreads in the direction in which the irregularities are arranged. As described above, when the direction of the processing mark and the incident surface of the excitation light are made parallel, the direction in which the diffused and reflected excitation light spreads becomes the direction perpendicular to the incident surface of the excitation light and does not enter the window portion. Therefore, the amount of excitation light directed toward the window can be further suppressed. When the processing mark is arcuate, the arc tangent at the excitation light irradiation position is made parallel to the incident surface.

  In the fluid sample measuring device according to the present invention, the light that passes through the fluid sample and is specularly reflected by the side wall surface of the cylindrical portion does not go to the window portion of the cylindrical portion, so this reflected light is introduced into the detection optical system. There is nothing to do. Moreover, in the fluid sample measuring device according to the present invention, the fluid sample does not stay, so that the fluid sample can be measured accurately.

The figure explaining the structure of the gas component measuring device which is one Example of the fluid sample measuring device which concerns on this invention. The figure explaining the direction of the diffuse reflection of the excitation light in a reflective surface. The figure explaining the structure of the gas component measuring apparatus which is another Example. The figure explaining the structure of the gas component measuring apparatus which is another Example.

Hereinafter, embodiments of the fluid sample measuring device according to the present invention will be described.
As shown in FIG. 1, the fluid sample measuring device of this embodiment is provided in a branch pipe 12 connected to a main pipe 11 through which a gas to be measured flows, and a gas for measuring the gas to be measured flowing through the branch pipe 12. It is a component measuring device. In FIG. 1, the inner diameter of the main pipe 11 and the inner diameter of the branch pipe 12 are shown to be approximately the same in order to illustrate the constituent parts of the gas component measuring apparatus. 11 is set to be sufficiently smaller than the inner diameter of 11, and a very small part of the gas to be measured flowing through the main pipe 11 is sampled and introduced into the branch pipe 12.

  The gas component measuring apparatus according to the present embodiment reflects a laser light source 13 that emits excitation light to irradiate a gas to be measured, and light emitted from the laser light source 13 in the direction of the window 15 provided on the side wall surface of the branch pipe 12. Of the Raman scattered light from the sample at the measurement point M inside the reflecting member 16 and the branch tube 12 disposed in the region including the position on the optical axis of the excitation light on the side wall surface of the mirror 14 and the branch tube 12, the window A light receiving optical system 17 including a lens that collects light emitted from the unit 15 and a detector 18 that detects light collected by the light receiving optical system 17 are provided. In addition, an irradiation optical system (not shown) including a lens or the like for condensing the light emitted from the laser light source 13 at the measurement point M is appropriately used. The laser light source 13 and the irradiation optical system correspond to the excitation optical system of the present invention, and the light receiving optical system 17 and the detector 18 correspond to the detection optical system of the present invention.

  The reflecting surface of the reflecting member 16 is set in a direction having a normal line that is not parallel to the optical axis of the excitation light. Thereby, the light (transmitted light) that has passed through the gas to be measured and reached the side wall surface of the branch pipe 2 is specularly reflected in the direction other than the window portion 15, passes through the window portion 15 and the light receiving optical system 17, and is detected by the detector 18. Is prevented from entering.

  The reflecting surface of the reflecting member 16 of the present embodiment is set in such a direction that the transmitted light is specularly reflected to the downstream side where the gas to be measured flows. The reflection surface may be in any other direction as long as the transmitted light is specularly reflected in a direction other than the window portion 15, but if the reflection surface faces the upstream side, the reflection surface is caused by dust contained in the gas. Contamination and damage may occur and noise light may increase. Therefore, it is desirable that the reflecting surface be set so that the excitation light reflects the downstream side where the gas to be measured flows.

By adopting the above configuration, it is possible to prevent the transmitted light specularly reflected by the reflecting surface from entering the detector. However, since the light diffusely reflected on the reflecting surface travels in various directions, when the amount of diffuse reflected light increases, a part of the diffuse reflected light enters the detector 18 through the window 15 and the light receiving optical system 17. . Therefore, in this embodiment, the reflecting surface is smoothed by machining. Thereby, more transmitted light is specularly reflected to suppress the amount of diffusely reflected light. In addition, the reflective surface is subjected to black plating treatment to increase the light absorption rate and suppress the amount of diffuse reflected light.

When the reflecting surface is smoothed by machining, usually, a linear or arcuate processing mark is formed on the reflecting surface. A linear processing mark is formed on the reflecting surface of the present embodiment.
As shown in FIG. 2 (a), the direction in which the processing mark extends (hereinafter referred to as "the direction of the processing mark"), the optical axis of the excitation light incident on the reflection surface, and the excitation light light that is specularly reflected by the reflection surface. When the plane including the axis (hereinafter, referred to as “excitation light incident surface”) is parallel, the direction in which fine irregularities exist between the processing marks is the direction perpendicular to the excitation light incident surface. Although the diffusely reflected excitation light spreads in the direction in which the unevenness exists, this light does not go to the window portion 15. On the other hand, as shown in FIG. 2B, when the direction of the processing mark and the incident surface of the excitation light are perpendicular, the excitation light diffusely reflected by the reflecting surface spreads in the in-plane direction of the incident surface of the excitation light, A part of it reaches the window 15. Therefore, in this embodiment, the processing member formed on the reflecting surface is arranged on the reflecting member 16 so that the direction of the processing mark is parallel to the incident surface of the excitation light. In the case where the processing mark has an arc shape, the reflecting member may be arranged so that the arc tangent at the excitation light irradiation position is parallel to the incident surface.

The surface accuracy and the degree of plating treatment can be appropriately set according to the required measurement accuracy. Therefore, when not required so much high measurement accuracy, for example, may be used a reflecting surface of the low-cost surface accuracy by performing only machining is suppressed to Ra ≦ 3.2μ m. On the other hand, when extremely high measurement accuracy is required, in the region near the measurement point M of the branch pipe 12, it is preferable to subject the inner wall surface to a diffuse antireflection treatment such as a black plating treatment. Thereby, the possibility that the transmitted light is diffusely reflected by the wall surface of the branch pipe 12 and enters the detection unit 18 can be further reduced.

  FIG. 3 shows a main configuration of a gas component measuring apparatus which is another embodiment of the fluid sample measuring apparatus according to the present invention. Similarly to the above, this gas component measuring device also includes a light source 23, a mirror 24, a window 25, a reflecting member 26, a light receiving optical system 27, and a detector 28. In the embodiment of FIG. 1, the light (transmitted light) transmitted through the measurement gas is specularly reflected downstream of the gas by tilting the reflection surface of the reflection member 16 disposed on the side wall surface of the branch pipe 12. In this embodiment, the transmitted light is specularly reflected downstream of the gas by tilting the branch tube 22 with respect to the excitation optical system including the light source 23 and the mirror 24 and the detection optical system including the light receiving optical system 27 and the detector 28. I am letting.

  In this configuration, the reflecting surface of the reflecting member 26 can be parallel to the side wall surface of the branch pipe 22. The reflecting surface only needs to be provided so that the transmitted light is specularly reflected in a direction other than the window portion 25. However, if the reflecting surface is set parallel to the side wall surface of the branch tube 22, the reflecting member 26 can be easily manufactured. Also in the configuration of the present embodiment, it is desirable to suppress the diffuse reflection of transmitted light by subjecting the reflective surface of the reflective member 26 to appropriate surface processing and black plating.

  FIG. 4 shows the configuration of the main part of a gas component measuring apparatus which is still another embodiment of the fluid sample measuring apparatus according to the present invention. This gas component measuring apparatus also includes a light source 33, a mirror 34, a window 35, a reflecting member 36, a light receiving optical system 37, and a detector 38, as in the two embodiments described above. In this embodiment, the inner diameter of the branch pipe 32 is increased in the region where the reflecting member 36 is disposed, and the above-described configuration is such that no step is generated on the side wall surface even when the reflecting member 36 is disposed. Different from the configuration of the embodiment. In the configuration of the embodiment described with reference to FIGS. 1 and 3, a step is generated on the side wall surfaces of the branch pipes 12 and 22 by disposing the reflecting members 16 and 26. Dust contained in the gas to be measured may adhere to the surface to be measured. When dust adheres, the adhered dust collects and a lump is formed, and this lump may gradually become large and cover the reflective surface. When excitation light is applied to a lump of dust that covers the reflective surface, noise light is generated. If this noise light is taken in during gas measurement, an error will occur in the measurement. On the other hand, in the configuration shown in FIG. 4, since there is no step at the position of the reflecting member 36, dust of the gas to be measured does not adhere, and there is no risk of errors in measurement due to noise light derived from the dust. .

Each of the above-described embodiments is an example, and can be appropriately changed in accordance with the gist of the present invention. In the above embodiment, a part of the gas to be measured flowing through the main pipe 11 is introduced into the branch pipe 12 and the gas to be measured is measured in the branch pipe 12. The same configuration can be adopted when measuring.
Moreover, although all the above-mentioned embodiments are apparatuses for measuring Raman scattered light from the gas to be measured, the sample to be measured may be a liquid, or may be an apparatus for measuring light emission from the sample. .
Further, in each of the above embodiments, a reflecting member different from the branch pipe is disposed on the side wall surface of the branch pipe. However, for example, in the configuration shown in FIG. can do. In this case, it is preferable to perform a flattening process or a plating process on the region used as the reflecting surface in the side wall surface of the branch pipe.

11 ... Main pipes 12, 22, 32 ... Branch pipes 13, 23, 33 ... Laser light sources 14, 24, 34 ... Mirrors 15, 25, 35 ... Window portions 16, 26, 36 ... Reflective members 17, 27, 37 ... Light reception Optical system 18, 28, 38 ... Detector M ... Measuring point

Claims (5)

a) a cylindrical part through which a fluid sample flows;
b) a window portion provided on the side wall surface of the cylindrical portion;
c) an excitation optical system that irradiates the measurement point inside the cylindrical portion with excitation light through the window;
d) a detection optical system for detecting measurement light from the fluid sample at the measurement point through the window;
e) a reflecting portion having a reflecting surface having a normal line that is non-parallel to the optical axis of the excitation light, provided in a region including a position on the optical axis of the excitation light on the side wall surface of the cylindrical portion;
Equipped with a,
A fluid sample measuring device, wherein the reflective surface is black-plated . The reflection surface is smoothed, and the direction of the processing mark formed by the processing is such that the optical axis of the excitation light incident on the reflection surface and the optical axis of the excitation light specularly reflected by the reflection surface The fluid sample measuring device according to claim 1, wherein the fluid sample measuring device is parallel to a plane containing the fluid sample.   a) a cylindrical part through which a fluid sample flows;
  b) a window portion provided on the side wall surface of the cylindrical portion;
  c) an excitation optical system that irradiates the measurement point inside the cylindrical portion with excitation light through the window;
  d) a detection optical system for detecting measurement light from the fluid sample at the measurement point through the window;
  e) a reflecting portion having a reflecting surface having a normal line that is non-parallel to the optical axis of the excitation light, provided in a region including a position on the optical axis of the excitation light on the side wall surface of the cylindrical portion;
With
  The reflection surface is smoothed, and the direction of the processing mark formed by the processing is such that the optical axis of the excitation light incident on the reflection surface and the optical axis of the excitation light specularly reflected by the reflection surface Parallel to the containing plane
  A fluid sample measuring device. Fluid sample measuring device according to any one of claims 1 to 3 in which the arithmetic mean roughness Ra of the surface accuracy of the reflecting surface is characterized by a Ra ≦ 3.2 .mu.m.   The fluid sample measurement device according to claim 1, wherein the reflection surface reflects excitation light transmitted through the fluid sample to a downstream side through which the fluid sample flows.

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