Patent Description:
As a method of analyzing a composition of a fluid, there are methods of analyzing Raman scattered light from a fluid irradiated with excitation light by irradiating the fluid with excitation light. Examples of devices which perform these methods include the composition analysis device described in Patent Document <NUM> which will be described below. The composition analysis device includes a measurement cell having a fluid flowing therein, a laser oscillator which oscillates laser light which is excitation light, an emission optical system which irradiates the fluid in the measurement cell with laser light from the laser oscillator, a light receiving optical system which receives Raman scattered light from the fluid irradiated with laser light, an optical fiber which receives the Raman scattered light condensed using the light receiving optical system, and an analyzing device which is configured to analyze light received using the optical fiber.

An optical axis of the emission optical system extends in a flow perpendicular direction perpendicular to a main flow direction of the fluid flowing in the measurement cell. The emission optical system is provided on one side in the flow perpendicular direction with reference to the measurement cell. An optical axis of the light receiving optical system coincides with the optical axis of the emission optical system. Thus, the optical axis of the light receiving optical system also extends in the flow perpendicular direction. The light receiving optical system is provided on the other side in the flow perpendicular direction with reference to the measurement cell.

[Patent Document <NUM>] discloses an optical measurement probe device for carrying out spectrometric and/or photometric measurements in a fluid, including a body, at least a first and a second arm extending to the end of said body and aligned with same, and defining a measurement cavity, a plurality of optical fibers inserted in said body, and optical coupling means capable of transmitting light between at least one portion of said optical fibers and the measurement cavity.

[Patent Document <NUM>] discloses that four heat receiving fins projecting outward in the radial direction are arranged on a lens cylinder of an incident hole lens set on an observation window of an insertion part so as to shift the phase thereof each other by <NUM>° and an illuminating light projected from a light guide is used as a heat source and this heat is transmitted to the incident hole lens through the lens cylinder from the heat receiving fins to heat them incident hole lens. This heat receiving fins are inserted in recessed parts formed on the projecting end face of the light guide and are brought into contact with this projecting end face.

In the composition analysis industry, it is desired to reduce the size of a composition analysis device.

Therefore, an object of the present invention is to provide a technique capable of reducing a size of a device.

According to the present invention, there is provided a Raman scattered light acquisition device as set out in independent claim <NUM>. Advantageous developments are defined in the dependent claims.

A Raman scattered light acquisition device as an aspect associated with the invention (which is defined with claim <NUM>) for achieving the above object includes: an emission optical system which is configured to guide excitation light from a light emission unit into a fluid; a scattered light window which is configured to define a part of a flow path of the fluid and through which Raman scattered light from the fluid irradiated with the excitation light passes; and a scattered light receiving device which has a light receiving surface receiving the Raman scattered light which has passed through the scattered light window, wherein the scattered light window and the light receiving surface of the scattered light receiving device are disposed at positions in which the scattered light window and the light receiving surface are separated from an optical axis in the fluid in a radial direction which is a direction perpendicular to the optical axis in the fluid within a range in which an optical path of the excitation light in the fluid is present in an optical axis direction in which the optical axis in the fluid which is an optical axis of the excitation light in the fluid extends, and the light receiving surface faces a radially inward side which is a side in proximity to the optical axis in the fluid in the radial direction.

In this aspect, the light receiving surface of the scattered light receiving device is arranged at a position in which the light receiving surface is separated from a scattered light generation region in the fluid in the direction perpendicular to the optical axis in the fluid. For this reason, in this aspect, the light receiving surface of the scattered light receiving device can be brought into proximity to the scattered light generation region in the fluid. Thus, in this aspect, it is possible to reduce a size of the Raman scattered light acquisition device.

Also, in this aspect, the light receiving surface of the scattered light receiving device can be brought into proximity to the scattered light generation region in the fluid. Thus, the light receiving surface of the scattered light receiving device can receive Raman scattered light with little attenuation. For this reason, in this aspect, the condensing optical system configured to condense scattered light which has passed through the scattered light window can be omitted. Thus, in this aspect, also from this viewpoint, it is possible to reduce the size of the Raman scattered light acquisition device.

Here, in the Raman scattered light acquisition device, a light receiving surface optical axis which is the optical axis in the light receiving surface of the scattered light receiving device may be perpendicular to the optical axis in the fluid.

In this aspect, it is possible to efficiently receive Raman scattered light which travels in the direction perpendicular to the optical axis in the fluid with a short optical path length.

Also, in any of the above Raman scattered light acquisition devices, the inner surface in the scattered light window which is configured to define the flow path of the fluid and the outer surface opposite to the inner surface may be both parallel to the optical axis in the fluid.

In this aspect, the Raman scattered light emitted in the direction perpendicular to the optical axis in the fluid in the Raman scattered light emitted from the fluid can be made to travel in a straight line. For this reason, it is possible to shorten an optical path length of scattered light from the optical axis in the fluid to the light receiving surface of the scattered light receiving device.

In any of the above Raman scattered light acquisition devices, the emission optical system may include an emission optical fiber cable through which the excitation light from the light emission unit passes and a changer which is configured to change a direction of the excitation light emitted from the emission optical fiber cable. In this case, an emission surface optical axis which is an optical axis in an emission surface of the emission optical fiber cable which emits the excitation light may extend in a direction intersecting the optical axis in the fluid. The emission surface of the emission optical fiber cable and the changer may be arranged on one side in the optical axis direction with reference to the light receiving surface of the scattered light receiving device and the changer may cause the optical axis of the excitation light emitted from the emission optical fiber cable to coincide with the optical axis in the fluid.

In this aspect, a width of the Raman scattered light acquisition device in the optical axis direction can be reduced.

Also, in the Raman scattered light acquisition device having the emission optical fiber cable, the emission surface optical axis may be perpendicular to the optical axis in the fluid.

In this aspect, the width of the Raman scattered light acquisition device in the optical axis direction can be made smaller.

Any of the above Raman scattered light acquisition devices may include: a light shielding member through which the excitation light and the Raman scattered light do not pass; and a heating optical fiber cable using which the light shielding member is irradiated with excitation light. The light shielding member is in contact with an outer surface of the scattered light window on the light receiving surface side.

In this aspect, it is possible to heat the scattered light window using energy of the excitation light. For this reason, in this aspect, it is possible to remove foreign matter adhered to the inner surface of the scattered light window and to prevent adhering of foreign matter to the scattered light window.

Also, since electricity is not used to heat the scattered light window in this aspect, an explosion-proofing treatment necessary for components for heating the scattered light window, that is, for the heating optical fiber cable and the heating light shielding member can be omitted.

In the Raman scattered light acquisition device including the light shielding member, a cavity which extends along the outer surface of the scattered light window is formed inside the light shielding member and the heating optical fiber cable is configured to emit into the cavity of the light shielding member.

Since the light shielding member can be irradiated with all of the excitation light in this aspect, it is possible to increase the efficiency of converting light energy of the excitation light into heat energy.

The Raman scattered light acquisition device includes an excitation light receiving optical system which is configured to receive the excitation light from the emission optical system; and a determination unit which is configured to determine an abnormality of an excitation light optical system constituted of a plurality of members through which the excitation light passes in accordance with a difference between the light intensity of the excitation light from the light emission unit and the light intensity of the excitation light received by the excitation light receiving optical system.

In this aspect, it is possible to recognize an abnormality in the excitation light optical system constituted of the plurality of members through which the excitation light passes.

In the Raman scattered light acquisition device including the excitation light receiving optical system, the excitation light receiving optical system may be arranged on a side opposite to the emission optical system in the optical axis direction with reference to the light receiving surface of the scattered light receiving device.

Any of the above Raman scattered light acquisition devices may include the light emission unit.

A composition analysis device as an aspect associated with the invention for achieving the above object includes: any of the above Raman scattered light acquisition devices; and an analyzing device which is configured to analyze a composition of the fluid on the basis of an output from the scattered light receiving device.

In this aspect, it is possible to analyze the composition of the fluid.

Here, in the composition analysis device, a distance in the radial direction from the optical axis in the fluid to the light receiving surface of the scattered light receiving device may be equal to or less than a distance in which an amount of the Raman scattered light received by the scattered light receiving device is a minimum amount of light in which the analyzing device is able to analyze the composition of the fluid.

A gas turbine plant as an aspect associated with the invention for achieving the above object includes: any of the above composition analysis devices; a fuel gas line through which a fuel gas as the fluid flows; a fuel adjustment valve which is configured to adjust a flow rate of the fuel gas flowing through the fuel gas line; a gas turbine configured to be driven through combustion of the fuel gas from the fuel gas line; and a control device which is configured to instruct a degree of opening of the fuel adjustment valve. The Raman scattered light acquisition device is attached to the fuel gas line. The analyzing device is configured to analyze a composition of the fuel gas flowing in the fuel gas line. The control device is configured to determine the degree of opening of the fuel adjustment valve in accordance with the analysis results in the analyzing device and instruct the degree of opening to the fuel adjustment valve.

According to the present invention, it is possible to reduce the size of a device.

An embodiment of a composition analysis device associated with the present invention and an embodiment of a gas turbine plant including the composition analysis device will be described below with reference to the drawings.

A first embodiment of the composition analysis device associated with the present invention and the embodiment of the gas turbine plant including the composition analysis device will be described with reference to <FIG>.

A fluid analyzed by the composition analysis device in this embodiment is, for example, a fuel gas flowing in a pipe. To be specific, as illustrated in <FIG>, the fluid is a fuel gas for driving a gas turbine of the gas turbine plant.

The gas turbine plant includes a gas turbine <NUM>, an electric generator <NUM> which generates electricity through driving of the gas turbine <NUM>, a gas compressor <NUM> which compresses a fuel gas through driving of the gas turbine <NUM>, a composition analysis device <NUM> which analyzes a composition of a gas to be supplied to the gas turbine <NUM>, and a control device <NUM> which controls a state or the like of the gas turbine <NUM>.

The gas turbine <NUM> includes an air compressor <NUM> which compresses air A to generate compressed air, a combustor <NUM> which combusts a fuel gas in the compressed air to generate a high-temperature combustion gas, and a turbine <NUM> which is driven using the combustion gas.

The air compressor <NUM> includes a compressor rotor, a compressor casing which rotatably covers the compressor rotor, and an intake amount adjuster <NUM> which adjusts an amount of intake of the air A. The intake amount adjuster <NUM> includes an inlet guide vane <NUM> provided on a suction port side of the compressor casing and a guide vane driver <NUM> which changes a degree of opening of the inlet guide vane <NUM>.

The turbine <NUM> includes a turbine rotor which rotates using a combustion gas and a turbine casing which rotatably covers the turbine rotor. The compressor rotor and the turbine rotor are connected to each other and integrally formed to form a gas turbine rotor <NUM>.

The electric generator <NUM> includes an electric generator rotor and an electric generator casing which rotatably covers the electric generator rotor. The electric generator rotor is connected to the gas turbine rotor <NUM>. For this reason, if the gas turbine rotor <NUM> rotates, the electric generator rotor also rotates integrally.

The gas compressor <NUM> includes a compressor rotor, a compressor casing which rotatably covers the compressor rotor and an intake gas amount adjuster <NUM> which adjusts an amount of intake of a fuel gas. The intake gas amount adjuster <NUM> includes an inlet guide vane <NUM> provided on a suction port side of the compressor casing and a guide vane driver <NUM> which changes a degree of opening of the inlet guide vane <NUM>. The compressor rotor of the gas compressor <NUM> is mechanically connected to the electric generator rotor or the gas turbine rotor <NUM> via a speed reducer <NUM>. A discharge port of the gas compressor <NUM> is connected to the combustor <NUM> through a high-pressure fuel gas line <NUM>.

A fuel gas is supplied from a steel mill <NUM> and a coke plant <NUM> to the gas turbine plant. The steel mill <NUM> generates a blast furnace gas (BFG) as a low-calorie fuel gas from a blast furnace in the steel mill <NUM>. A BFG line <NUM> through which a BFG flows is connected to the blast furnace. The coke plant <NUM> generates a coke oven gas (COG) as a high-calorie fuel gas from a coke oven in the coke plant <NUM>. A COG line <NUM> through which a COG flows is connected to the coke oven. A COG adjustment valve <NUM> which adjusts a flow rate of the COG is provided in the COG line <NUM>. The BFG line <NUM> and the COG line <NUM> are joined to form a low-pressure fuel gas line <NUM>. Any of an independent BFG, an independent COG, and a mixture of a BFG and a COG flows through the low-pressure fuel gas line <NUM>. The low-pressure fuel gas line <NUM> is connected to the suction port of the gas compressor <NUM>. An electrostatic precipitator (EP) <NUM> which collects dust and the like in a gas passing through the low-pressure fuel gas line <NUM> is provided in the low-pressure fuel gas line <NUM>. A gas such as a Linz-Donawitz converter gas (LDG) which is a gas generated in a converter in the middle of the BFG line <NUM> may be mixed in in the BFG line <NUM> in some cases.

The gas turbine plant includes the BFG line <NUM>, the COG line <NUM>, the low-pressure fuel gas line <NUM>, the COG adjustment valve <NUM>, and the electrostatic precipitator <NUM> which have been described above. The gas turbine plant further includes a fuel gas circulation line <NUM>, a circulation amount adjustment valve <NUM>, and a gas cooler <NUM>. A first end of the fuel gas circulation line <NUM> is connected to the high-pressure fuel gas line <NUM>. Furthermore, a second end of the fuel gas circulation line <NUM> is connected to a position of the low-pressure fuel gas line <NUM> upstream of the electrostatic precipitator <NUM>. The gas cooler <NUM> and the circulation amount adjustment valve <NUM> are provided in the fuel gas circulation line <NUM>.

The gas cooler <NUM> cools a gas flowing through the fuel gas circulation line <NUM>. If a degree of opening of the circulation amount adjustment valve <NUM> is changed and a flow rate of the gas flowing through the fuel gas circulation line <NUM> is changed, a flow rate of a gas supplied to the combustor <NUM> is also changed. For this reason, the circulation amount adjustment valve <NUM> functions as a fuel adjustment valve which adjusts a flow rate of a fuel gas to be supplied to the combustor <NUM>. Furthermore, the intake gas amount adjuster <NUM> of the gas compressor <NUM> described above also functions as a fuel adjustment valve. The composition analysis device <NUM> is provided in the BFG line <NUM>. The composition analysis device <NUM> analyzes a composition of a BFG flowing through the BFG line <NUM>. Here, although the composition analysis device <NUM> is provided in the BFG line <NUM>, the composition analysis device <NUM> may be provided in the low-pressure fuel gas line <NUM> or the COG line <NUM> in some cases.

The control device <NUM> controls a degree of opening of the circulation amount adjustment valve <NUM>, a degree of opening of the inlet guide vane <NUM>, or the like in accordance with a load command from the outside, a composition of a BFG which is a gas analyzed by the composition analysis device <NUM>, or the like. Furthermore, the control device <NUM> also controls a degree of opening of the COG adjustment valve <NUM> in accordance with a load command from the outside, a composition of a gas G (a BFG) analyzed by the composition analysis device <NUM>, or the like in some cases.

As illustrated in <FIG>, the composition analysis device <NUM> includes a Raman scattered light acquisition device <NUM> which acquires Raman scattered light from a fluid G irradiated with laser light which is excitation light and an analyzing device <NUM> which analyzes a composition of the fluid G on the basis of the Raman scattered light acquired by the Raman scattered light acquisition device <NUM>.

Hereinafter, the Raman scattered light may also be simply referred to as "scattered light" in some cases.

The Raman scattered light acquisition device <NUM> includes a scattered light acquisition head <NUM>, an analyzing laser oscillator (a light emission unit) <NUM>, a heating laser oscillator <NUM>, a control unit <NUM> which controls the laser oscillators <NUM> and <NUM>, two determination units <NUM> and <NUM> which determine the intensity of laser light, and a determination unit <NUM> which determines a state of the scattered light acquisition head <NUM> in accordance with outputs from the two determination units <NUM> and <NUM>.

The analyzing laser oscillator <NUM> oscillates laser light with which the fluid G is irradiated. The heating laser oscillator <NUM> oscillates laser light which heats a part of the scattered light acquisition head <NUM>.

The scattered light acquisition head <NUM> includes a head casing <NUM>, an emission optical system <NUM> which guides laser light from the analyzing laser oscillator <NUM> which is a light emission unit into the fluid G, a laser light receiving optical system (an excitation light receiving optical system) <NUM> which receive laser light which has passed through the fluid G, a scattered light window <NUM> which defines a part of a flow path of the fluid G and through which Raman scattered light from the fluid G passes, a scattered light receiving device <NUM> which receives the Raman scattered light which has passed through the scattered light window <NUM>, a light shielding member <NUM> in contact with the scattered light window <NUM>, and a heating optical fiber cable <NUM> which guides heating laser light to the light shielding member <NUM>.

The emission optical system <NUM> includes an emission optical fiber cable <NUM> through which laser light from the analyzing laser oscillator <NUM> passes, an emission prism (a changer) <NUM> which changes a direction of laser light emitted from the emission optical fiber cable <NUM>, and a laser emission window <NUM> which defines a part of the flow path of the fluid G and through which laser light passes.

The emission optical fiber cable <NUM> has an optical fiber (not shown), a covering member (not shown) which covers the outer circumference of the optical fiber, and a sleeve <NUM> which covers an outer circumference of an end of the optical fiber. The sleeve <NUM> of the emission optical fiber cable <NUM> on an emission side thereof is attached to the head casing <NUM>.

The emission prism <NUM> perpendicularly bends an optical axis of laser light emitted from the emission optical fiber cable <NUM>. In other words, the emission prism <NUM> makes an optical axis of laser light which has passed through the emission prism <NUM> perpendicular to an optical axis Ao of an emission surface of the emission optical fiber cable <NUM>. The optical axis Ao of the emission surface is an optical axis of an emission surface <NUM> from which laser light is emitted through the emission optical fiber cable <NUM>. The emission prism <NUM> is arranged in the head casing <NUM> and is fixed to the head casing <NUM>.

Laser light whose direction is changed through the emission prism <NUM> passes through the laser emission window <NUM>. An inner surface 22i in the laser emission window <NUM> which defines the flow path of the fluid G and an outer surface 22o in the laser emission window <NUM> on the emission prism <NUM> side are both perpendicular to an optical axis of laser light which has passed through the emission prism <NUM>. For this reason, an optical axis of laser light which has passed through the emission prism <NUM> and which does not reach the laser emission window <NUM> coincides with an optical axis Aw in a fluid which is an optical axis of laser light which has passed through the laser emission window <NUM> and has reached the fluid G. The laser emission window <NUM> is fixed to the head casing <NUM>.

The emission optical system <NUM> described above does not have a condensing optical system. However, a condensing optical system which condenses laser light emitted from the emission optical fiber cable <NUM> into the fluid G may be provided.

The laser light receiving optical system (the excitation light receiving optical system) <NUM> includes a laser receiving window <NUM> which defines a part of the flow path of the fluid G and through which laser light passes, a light receiving prism <NUM> which changes a direction of laser light which has passed through the laser receiving window <NUM>, a laser receiving optical fiber cable <NUM> on which laser light which has passed through the light receiving prism <NUM> is incident, and a condensing optical system <NUM> which condenses laser light which has passed through the light receiving prism <NUM> on a light receiving surface <NUM> of the laser receiving optical fiber cable <NUM>.

The laser receiving window <NUM> is arranged above the optical axis Aw in the fluid. The inner surface 32i in the laser receiving window <NUM> which defines the flow path of the fluid G and the outer surface 32o in the laser receiving window <NUM> on the light receiving prism <NUM> side are both perpendicular to the optical axis Aw in the fluid. For this reason, an optical axis of laser light which has passed through the laser receiving window <NUM> coincides with the optical axis Aw in the fluid. The laser receiving window <NUM> is fixed to the head casing <NUM>.

The light receiving prism <NUM> perpendicularly bends an optical axis of laser light which has passed through the laser receiving window <NUM>. In other words, the light receiving prism <NUM> makes the optical axis of the laser light which has passed through the light receiving prism <NUM> perpendicular to the optical axis Aw in the fluid. The light receiving prism <NUM> is arranged in the head casing <NUM> and is fixed to the head casing <NUM>.

The laser receiving optical fiber cable <NUM> has an optical fiber (not shown), a covering member (not shown) which covers an outer circumference of the optical fiber, and a sleeve <NUM> which covers an outer circumference of an end of the optical fiber. The sleeve <NUM> of the laser receiving optical fiber cable <NUM> on a light receiving side thereof is attached to the head casing <NUM>.

A light receiving surface optical axis Ai of the laser receiving optical fiber cable <NUM> coincides with the optical axis of the laser light which has passed through the light receiving prism <NUM>. The light receiving surface optical axis Ai is an optical axis of the light receiving surface <NUM> in the laser receiving optical fiber cable <NUM> which receives the laser light from the light receiving prism <NUM>.

Hereinafter, a direction in which the optical axis Aw in the fluid extends is assumed to be an "optical axis direction Da. " Furthermore, a direction in which the light receiving surface <NUM> of the laser receiving optical fiber cable <NUM> is present with respect to the optical axis Aw in the fluid among directions perpendicular to the optical axis Aw in the fluid is assumed to be a "radial direction Dr. " In this radial direction Dr, a side closer to the optical axis Aw in the fluid is assumed to be a radially inward side Dri and an opposite side is assumed to be a radially outward side Dro.

As described above, scattered light passes through the scattered light window <NUM> and laser light is reflected by the scattered light window <NUM>. The scattered light window <NUM> is arranged at a position in which the scattered light window <NUM> is separated from the optical axis Aw in the fluid in the radial direction Dr within the range Rw in which the optical path of the laser light in the fluid G is present in the optical axis direction Da. The inner surface 42i in the scattered light window <NUM> which defines the flow path of the fluid G and the outer surface 42o which is a surface in the scattered light window <NUM> opposite to the inner surface 42i are both parallel to the optical axis Aw in the fluid. The inner surface 42i of the scattered light window <NUM> faces the radially inward side Dri and the outer surface 42o of the scattered light window <NUM> faces the radially outward side Dro.

The scattered light receiving device <NUM> has a scattered light optical fiber cable <NUM> configured to receive scattered light which has passed through the scattered light window <NUM>. A light receiving surface <NUM> of the scattered light optical fiber cable <NUM> is arranged at a position in which the light receiving surface <NUM> is separated from the optical axis Aw in the fluid in the radial direction Dr within the range Rw in which the optical path of the laser light in the fluid G is present in the optical axis direction Da, as in the scattered light window <NUM>. Here, the light receiving surface <NUM> is located on the radially outward side Dro with respect to the scattered light window <NUM> and faces the radially inward side Dri. The scattered light optical fiber cable <NUM> has an optical fiber (not shown), a covering member (not shown) which covers an outer circumference of the optical fiber, and a sleeve <NUM> which covers an outer circumference of an end of the optical fiber. The sleeve <NUM> of the scattered light optical fiber cable <NUM> on a light receiving side thereof is attached to the head casing <NUM>.

The emission surface <NUM> of the emission optical fiber cable <NUM>, the light receiving surface <NUM> of the laser receiving optical fiber cable <NUM>, and the light receiving surface <NUM> of the scattered light optical fiber cable <NUM> are all arranged at positions in which they are separated from the optical axis Aw in the fluid in the radial direction Dr. Furthermore, the emission surface <NUM> of the emission optical fiber cable <NUM>, the light receiving surface <NUM> of the laser receiving optical fiber cable <NUM>, and the light receiving surface <NUM> of the scattered light optical fiber cable <NUM> are all surfaces parallel to the optical axis Aw in the fluid. Thus, the emission surface optical axis Ao of the emission optical fiber cable <NUM>, the light receiving surface optical axis Ai of the laser receiving optical fiber cable <NUM>, and a light receiving surface optical axis Ars of the scattered light optical fiber cable <NUM> are all parallel to each other and are perpendicular to the optical axis Aw in the fluid.

The light shielding member <NUM> is adhered to the outer surface 42o of the scattered light window <NUM> with an adhesive or the like. The light shielding member <NUM> is formed of a member through which laser light or Raman scattered light does not pass, which easily absorbs the energy of the laser light or the Raman scattered light, and which has good thermal conductivity. To be specific, the light shielding member <NUM> is formed of copper, brass, or an alloy containing these. As illustrated in <FIG> and <FIG>, an outer shape of the light shielding member <NUM> is annular. An inside of this annular shape forms an optical path through which scattered light passes. An annular cavity <NUM> which extends along the outer surface 42o of the scattered light window <NUM> and matches the outer shape of the light shielding member <NUM> is formed inside the light shielding member <NUM>.

The heating optical fiber cable <NUM> has an optical fiber (not shown), a covering member (not shown) which covers an outer circumference of the optical fiber, and a sleeve <NUM> which covers an outer circumference of an end of the optical fiber. The sleeve <NUM> of the heating optical fiber cable <NUM> on an emission side thereof is attached to the light shielding member <NUM>. To be specific, the sleeve <NUM> of the heating optical fiber cable <NUM> is attached to the light shielding member <NUM> from a direction inclined with respect to an inner surface of the cavity of the light shielding member <NUM> and the outer surface 42o of the scattered light window <NUM> so that laser light from the heating optical fiber cable <NUM> is emitted into the cavity <NUM> of the light shielding member <NUM>.

The head casing <NUM> has a main body section <NUM> and two protrusion sections <NUM> and <NUM>. A part of the sleeve <NUM> of the emission optical fiber cable <NUM>, a part of the sleeve <NUM> of the laser receiving optical fiber cable <NUM>, the condensing optical system <NUM>, the sleeve <NUM> of the scattered light optical fiber cable <NUM>, the light shielding member <NUM>, and the sleeve <NUM> of the heating optical fiber cable <NUM> are accommodated in the main body section <NUM> and they are attached to the main body section <NUM>. An attachment flange <NUM> configured to attach the head casing <NUM> to a pipe 131p through which a fluid G flows is provided in the main body section <NUM>. The pipe 131p is a pipe which constitutes the BFG line <NUM> through which a BFG flows. The two protrusion sections <NUM> and <NUM> protrude from the main body section <NUM> in a direction in which the two protrusion sections <NUM> and <NUM> become further away from the attachment flange <NUM>. The two protrusion sections <NUM> and <NUM> are separated from each other in a direction perpendicular to a direction in which the protrusion sections <NUM> and <NUM> protrude from the main body section <NUM>. The emission prism <NUM> is accommodated in a first protrusion section <NUM> of the two protrusion sections <NUM> and <NUM> and the emission prism <NUM> is attached to the first protrusion section <NUM>. Furthermore, the light receiving prism <NUM> is accommodated in a second protrusion section <NUM> which is the other protrusion section of the two protrusion sections <NUM> and <NUM> and the light receiving prism <NUM> is attached to the second protrusion section <NUM>. The laser emission window <NUM> is attached to a surface in the first protrusion section <NUM> facing the second protrusion section <NUM>. Furthermore, the laser receiving window <NUM> is attached to a surface in the second protrusion section <NUM> facing the first protrusion section <NUM>. Thus, the direction in which the two protrusion sections <NUM> and <NUM> are separated is the optical axis direction Da. Furthermore, a direction in which the two protrusion sections <NUM> and <NUM> protrude from the main body section <NUM> is the radial direction Dr. The scattered light window <NUM> is attached to a surface of the main body section <NUM> on the radially inward side Dri thereof between the two protrusion sections <NUM> and <NUM> in the optical axis direction Da.

In a state in which the head casing <NUM> is attached to the pipe <NUM>1p using the attachment flange <NUM>, the first protrusion section <NUM>, the second protrusion section <NUM>, and a portion of the main body section <NUM> on the radially inward side Dri are all located in the pipe 131p.

An emitted light determination unit <NUM> which is one determination unit of the two determination units <NUM> and <NUM> determines the intensity of laser light oscillated from the analyzing laser oscillator <NUM> or laser light passing through the emission optical fiber cable <NUM>. A light receiving determination unit <NUM> which is the other determination unit of the two determination units <NUM> and <NUM> determines the intensity of laser light which has passed through the laser receiving optical fiber cable <NUM>.

As described above, the determination unit <NUM> determines a state of the scattered light acquisition head <NUM> in accordance with outputs from the two determination units <NUM> and <NUM>. To be specific, for example, when a difference between the light intensity determined by the emitted light determination unit <NUM> and the light intensity determined by the light receiving determination unit <NUM> is a predetermined value or more, it is determined that the scattered light acquisition head <NUM> is abnormal. Examples of a form of an abnormality determined by the determination unit <NUM> include the following forms. There is an abnormal form of a direction of the optical axis Ao of the emission surface of an emitted light optical fiber cable and a direction of the light receiving surface optical axis Ai of the laser receiving optical fiber cable <NUM>. Furthermore, there is an abnormal form of the arrangement and direction of the emission prism <NUM> and the light receiving prism <NUM>. In addition, there is an abnormal form of the analyzing laser oscillator <NUM>. There is also a form in which the laser emission window <NUM> and the laser receiving window <NUM> are dirty.

The analyzing device <NUM> includes a spectroscope <NUM> which disperses scattered light received by the scattered light optical fiber cable <NUM> into light for each of a plurality of wavelength bands, a camera <NUM> which outputs light for each of the plurality of wavelength bands dispersed using the spectroscope <NUM> as a digital signal, and an analyzing unit <NUM> which analyzes a composition in the fluid G on the basis of the digital signal associated with the light for each of the plurality of wavelength bands.

A computer <NUM> has, as functional constitutions, the control unit <NUM>, the determination unit <NUM> and the analyzing unit <NUM> described above. All of the control unit <NUM>, the determination unit <NUM>, and the analyzing unit <NUM> are constituted to have a program stored in a memory or the like of the computer <NUM> and a central processing unit (CPU) which executes this program.

As illustrated in <FIG>, the control device <NUM> can communicate with the computer <NUM>. For example, the control device <NUM> outputs (displays) the determination result using the determination unit <NUM>. Furthermore, the control device <NUM> controls a degree of opening of the circulation amount adjustment valve <NUM>, a degree of opening of the inlet guide vane <NUM>, and in some cases, a degree of opening of the COG adjustment valve <NUM> and the like in accordance with the analysis result using the analyzing unit <NUM>.

An operation of the composition analysis device <NUM> described above will be described below.

The laser light oscillated from the analyzing laser oscillator <NUM> is incident on the emission optical fiber cable <NUM> and passes through the emission optical fiber cable <NUM>. The optical axis of the laser light emitted from the emission optical fiber cable <NUM> is bent perpendicularly through the emission prism <NUM>. The fluid G in the pipe 131p is irradiated with the laser light whose optical axis is bent through the laser emission window <NUM>.

If the fluid G is irradiated with excitation light, Raman scattered light with a specific wavelength is generated for each component in the fluid G. In other words, when the fluid G is irradiated with laser light with a predetermined wavelength, as illustrated in <FIG>, Raman scattered light whose wavelength is shifted from a wavelength of laser light by a specific amount of shift is generated for each component in the fluid G.

Scattered light is received by the scattered light optical fiber cable <NUM> through the scattered light window <NUM>. The scattered light is guided to the spectroscope <NUM> of the analyzing device <NUM> through the scattered light optical fiber cable <NUM>. The spectroscope <NUM> disperses incident scattered light for each of the plurality of wavelength bands. As shown in <FIG>, the camera <NUM> converts a light intensity for each of the plurality of wavelength bands dispersed using the spectroscope <NUM> into a digital signal and outputs the converted digital signal to the analyzing unit <NUM> of the computer <NUM>. The analyzing unit <NUM> analyzes a composition in the fluid G on the basis of a digital signal associated with light for each of the plurality of wavelength bands. The analyzing unit <NUM> pre-stores a relationship between a wavelength of laser light with which the fluid G is irradiated and an amount of shift of a wavelength of scattered light emitted from each component when the laser light is radiated. The analyzing unit <NUM> analyzes the component in the fluid G using this relationship. Furthermore, the analyzing unit <NUM> obtains a concentration of the component in the fluid G on the basis of an intensity of scattered light for each component. When the fluid G is a BFG which is a gas, the analyzing unit <NUM> obtains a high heating value (HHV) or a low heating value (LHV) of the BFG if necessary.

The following Expression (<NUM>) is an expression for obtaining a high heating value (HHV) per unit volume of the BFG when the BFG includes carbon dioxide (CO<NUM>), carbon monoxide (CO), nitrogen (N<NUM>), methane (CH<NUM>), water vapor (H<NUM>O), or hydrogen (H<NUM>) as illustrated in <FIG>. Furthermore, the following Expression (<NUM>) is an expression for obtaining a low heating value (LHV) per unit volume of the BFG in the same case. <NUM>] <MAT>
[Math. <NUM>] <MAT>.

The HHV is a calorific value (kcal/m<NUM>N) in which the heat of condensation of water generated through combustion of the BFG is included as a calorific value. The LHV is a calorific value (kcal/m<NUM>N) in which the heat of condensation of water generated through combustion of the BFG is not included as a calorific value. Furthermore, in the Expressions (<NUM>) to (<NUM>), CN<NUM> is a mole fraction of N<NUM>, CCO is a mole fraction of CO, CCO<NUM> is a mole fraction of CO<NUM>, CH<NUM>O is a mole fraction of H<NUM>O, CH<NUM> is a mole fraction of H<NUM>, and CCH<NUM> is a mole fraction of CH<NUM>. The mole fraction of each component can be calculated using the following Expressions (<NUM>) to (<NUM>). <NUM>] <MAT>.

<NUM>] <MAT>
[Math. <NUM>] <MAT>
[Math. <NUM>] <MAT>.

The analyzing unit <NUM> obtains a relative intensity ICO/IN<NUM> of a carbon monoxide component with respect to a light intensity IN<NUM> of a nitrogen component, a relative intensity ICO<NUM>/IN<NUM> of a carbon dioxide component to the light intensity IN<NUM> of the nitrogen component, a relative intensity IH<NUM>O/IN<NUM> of a water vapor component to the light intensity IN<NUM> of the nitrogen component, a relative intensity IH<NUM>/IN<NUM> of a hydrogen component to the light intensity IN<NUM> of the nitrogen component, and a relative intensity ICH<NUM>/IN<NUM> of a methane component to the light intensity IN<NUM> of the nitrogen component from the intensity of the scattered light for each component in the BFG. Subsequently, the analyzing unit <NUM> obtains the high heating value (HHV) or the low heating value (LHV) of the BFG using the relative intensity of each of the components, Expression (<NUM>) or (<NUM>) and Expressions (<NUM>) to (<NUM>). Although Expressions (<NUM>) to (<NUM>) are the expressions associated with a volume ratio in which H<NUM>O is taken into consideration, a calorific value may be obtained using an expression associated with a volume ratio of the gas in which H<NUM>O is excluded.

The concentration of the component in the fluid G, the low heating value (LHV), or the like obtained using the analyzing unit <NUM> is transmitted to the control device <NUM> of the gas turbine plant. As described above, the control device <NUM> controls the degree of opening of the circulation amount adjustment valve <NUM>, the degree of opening of the inlet guide vane <NUM>, and the like on the basis of data transmitted from the analyzing unit <NUM>, that is, the analysis result.

The laser light which has passed through the fluid G is incident on the light receiving prism <NUM> through the laser receiving window <NUM>. An optical axis of the laser light is perpendicularly bent through the light receiving prism <NUM>. The laser light whose optical axis is bent is condensed through the light receiving surface <NUM> of the laser receiving optical fiber cable <NUM> using the condensing optical system <NUM>. The light receiving determination unit <NUM> determines the intensity of the laser light incident on the laser receiving optical fiber cable <NUM>.

The intensity of laser light determined by the emitted light determination unit <NUM> and the intensity of laser light determined by the light receiving determination unit <NUM> are transmitted to the determination unit <NUM> of the computer <NUM>. As described above, the determination unit <NUM> determines a state of the scattered light acquisition head <NUM> in accordance with the intensity of the laser light determined by each of the determination units <NUM> and <NUM>. The determination result of the determination unit <NUM> is transmitted to the control device <NUM> of the gas turbine plant. The control device <NUM> causes the determination result of the determination unit <NUM> to be displayed if necessary.

The laser light oscillated from the heating laser oscillator <NUM> is guided into the cavity <NUM> of the light shielding member <NUM> through the heating optical fiber cable <NUM>. The laser light is repeatedly irregularly reflected by the inner surface of the cavity in the cavity <NUM> of the light shielding member <NUM>. As a result, light energy of the laser light is converted into heat energy using which the light shielding member <NUM> and the scattered light window <NUM> in contact with the light shielding member <NUM> are heated. That is to say, in this embodiment, the scattered light window <NUM> is heated using the energy of the laser light.

Also, since the laser light from the heating optical fiber cable <NUM> is guided into the cavity <NUM> of the light shielding member <NUM> in this embodiment, it is possible to irradiate the light shielding member <NUM> with all of the laser light and it is possible to increase the efficiency of converting the light energy of the laser light into heat energy.

Incidentally, when foreign matter is present in the fluid G, the inner surface 22i of the laser emission window <NUM> which partitions the inside of the head casing <NUM> and the flow path of the fluid G, the inner surface 32i of the laser receiving window <NUM>, and the inner surface 42i of the scattered light window <NUM> become contaminated by the foreign matter. For example, when the fluid G is one of a blast furnace gas (BFG) and a coke oven gas (COG) or a mixed gas of BFG and COG, foreign matter such as ash becomes present in the fluid G.

An intensity of the Raman scattered light is much smaller than an intensity of the laser light with which the fluid G is irradiated. For this reason, if the inner surface 42i of the scattered light window <NUM> is dirty, the foreign matter hinders the composition analysis of the fluid G based on the scattered light. Thus, in this embodiment, as described above, foreign matter adhered to the inner surface 42i of the scattered light window <NUM> is removed and adhering of foreign matter to the inner surface 42i of the scattered light window <NUM> is prevented by heating the scattered light window <NUM>.

As a method of heating the scattered light window <NUM>, there is a method of heating the scattered light window <NUM> wire by bringing the heating wire into contact with or into proximity to the scattered light window <NUM> and causing a current to pass through the heating wire. In this way, when the heating wire is brought into contact with or into proximity to the scattered light window <NUM> if the fluid G is a combustible gas such as a BFG or a COG, explosion-proof treatment needs to be applied to a heating wire or an electric cable through which a current is supplied to the heating wire. On the other hand, since electricity is not used to heat the scattered light window <NUM> in this embodiment, it is not necessary to apply explosion-proof treatment to a component necessary for heating the scattered light window <NUM>, specifically, the heating optical fiber cable <NUM> and the light heat shield member. Thus, in this embodiment, it is possible to save the cost of the explosion-proof treatment for the component necessary for heating the scattered light window <NUM>.

In this embodiment, as described above, the light receiving surface <NUM> of the scattered light receiving device <NUM> is arranged at a position in which the light receiving surface <NUM> is separated from the optical axis Aw in the fluid in the radial direction Dr within the range Rw in which the optical path of the laser light in the fluid G is present in the optical axis direction Da. In other words, in this embodiment, the light receiving surface <NUM> of the scattered light receiving device <NUM> is arranged at a position in which the light receiving surface <NUM> is separated from a scattered light generation region Rrs in the fluid G in a direction in which the light receiving surface <NUM> is perpendicular to the optical axis Aw in the fluid. For this reason, in this embodiment, the light receiving surface <NUM> of the scattered light receiving device <NUM> can be brought into proximity to the scattered light generation region Rrs in the fluid G. Moreover, in this embodiment, the inner surface 42i and the outer surface 42o of the scattered light window <NUM> and the light receiving surface <NUM> of the scattered light receiving device <NUM> are parallel to the optical axis Aw in the fluid. Thus, it is possible to shorten an optical path length of the scattered light from the scattered light generation region Rrs to the light receiving surface <NUM> of the scattered light receiving device <NUM>. Therefore, in this embodiment, it is possible to reduce sizes of the Raman scattered light acquisition device <NUM> and the composition analysis device <NUM> including the Raman scattered light acquisition device <NUM>.

Furthermore, in this embodiment, the light receiving surface <NUM> of the scattered light receiving device <NUM> can be brought into proximity to the scattered light generation region Rrs in the fluid G. Thus, the light receiving surface <NUM> of the scattered light receiving device <NUM> can receive Raman scattered light with little attenuation. For this reason, in this embodiment, the condensing optical system configured to condense the scattered light which has passed through the scattered light window <NUM> can be omitted. To be specific, in this embodiment, the condensing optical system can be omitted by setting a distance from the optical axis Aw in the fluid to the light receiving surface <NUM> of the scattered light receiving device <NUM> in a radial direction (a direction perpendicular to the optical axis in the fluid) to be equal to or less than a distance in which an amount of Raman scattered light to be received by the scattered light receiving device <NUM> is a minimum amount of light in which the composition of the fluid G can be analyzed using the analyzing device <NUM>. Thus, in this embodiment, also from this point of view, it is possible to reduce sizes of the Raman scattered light acquisition device <NUM> and the composition analysis device <NUM> including the Raman scattered light acquisition device <NUM>.

In addition, in this embodiment, as described above, all of the emission surface optical axis Ao of the emission optical fiber cable <NUM>, the light receiving surface optical axis Ai of the laser receiving optical fiber cable <NUM>, and the light receiving surface optical axis Ars of the scattered light optical fiber cable <NUM> are parallel to each other and are perpendicular to the optical axis Aw in the fluid. Thus, in this embodiment, it is possible to minimize widths in the optical axis direction Da of the Raman scattered light acquisition device <NUM> and the composition analysis device <NUM> including the Raman scattered light acquisition device <NUM>.

A second embodiment of the composition analysis device associated with the present invention will be described with reference to <FIG>.

The composition analysis device in this embodiment is different from the composition analysis device in the first embodiment in that the emission prism <NUM> and the light receiving prism <NUM> are in contact with the fluid G and a plurality of light shielding members 50a are provided but the other points are basically the same as those of the composition analysis device in the first embodiment.

The scattered light window 42a in this embodiment is arranged at a position in which the scattered light window 42a is separated from the optical axis Aw in the fluid in the radial direction Dr, as in the scattered light window 42a in the first embodiment. Also in the scattered light window 42a in this embodiment, both of the inner surface 42i which defines the flow path of the fluid G and the outer surface 42o which is a surface in the scattered light window <NUM> opposite to the inner surface 42i are parallel to the optical axis Aw in the fluid. Here, the length of the scattered light window 42a in this embodiment in the optical axis direction Da is longer than that of the scattered light window <NUM> in the first embodiment. To be specific, the scattered light window 42a in this embodiment extends in the optical axis direction Da to a position farther than a position of the emission surface optical axis Ao of the emission optical fiber cable <NUM> with reference to the light receiving surface optical axis Ars of the scattered light optical fiber cable <NUM>. Furthermore, the scattered light window 42a in this embodiment extends in the optical axis direction Da to a position farther than a position of the light receiving surface optical axis Ai of the laser receiving optical fiber cable <NUM> with reference to the light receiving surface optical axis Ars of the scattered light optical fiber cable <NUM>. That is to say, the scattered light window 42a in this embodiment is also present in the optical axis direction Da at a position of the emission surface optical axis Ao of the emission optical fiber cable <NUM> and a position of the light receiving surface optical axis Ai of the laser receiving optical fiber cable <NUM>. For this reason, the scattered light passes through the scattered light window 42a in this embodiment within the range Rw in which the optical path of the laser light in the fluid G is present in the optical axis direction Da and the scattered light window 42a is subjected to a process of reflecting the laser light. In addition, the scattered light window 42a is not subjected to a process of reflecting laser light and the laser light passes through the scattered light window 42a outside of the range Rw.

The emission optical system 21a in this embodiment has the emission optical fiber cable <NUM> through which laser light from the analyzing laser oscillator <NUM> passes, a part of the scattered light window 42a, and the emission prism (the changer) <NUM> which changes a direction of laser light which is emitted from the emission optical fiber cable <NUM> and has passed through the scattered light window 42a. An incident surface 23i of the emission prism <NUM> is in contact with the outer surface 42o of the scattered light window 42a. On the other hand, an emission surface 23o of the emission prism <NUM> forms a surface which defines the flow path of the fluid G. For this reason, the emission optical system 21a in this embodiment does not have the laser emission window <NUM>.

The laser light receiving optical system (the excitation light receiving optical system) 31a includes the light receiving prism <NUM> which changes a direction of laser light, a part of the scattered light window 42a, the laser receiving optical fiber cable <NUM>, and the condensing optical system <NUM> which condenses laser light which has passed through the light receiving prism <NUM> and the scattered light window 42a to the light receiving surface <NUM> of the laser receiving optical fiber cable <NUM>. The incident surface 23i of the light receiving prism <NUM> forms a surface which defines the flow path of the fluid G. For this reason, the laser light receiving optical system 31a in this embodiment does not have the laser receiving window <NUM>. The emission surface 33o of the light receiving prism <NUM> is in contact with the outer surface 42o of the scattered light window 42a.

As described above, since the laser emission window <NUM> and the laser receiving window <NUM> in the first embodiment are not provided in this embodiment, it is possible to simplify a device and to minimize the production costs thereof.

In the first embodiment, one light shielding member <NUM> is provided and an outer shape thereof is annular. On the other hand, in this embodiment, as described above, a plurality of light shielding members 50a are provided. All of the plurality of light shielding members 50a are adhered to the outer surface 42o of the scattered light window 42a with an adhesive or the like. The light shielding member <NUM> is formed of a member through which laser light or Raman scattered light is not transmitted, which easily absorbs the energy of the laser light or the Raman scattered light, and which has good thermal conductivity. The plurality of light shielding members 50a are separated from each other in a circumferential direction with respect to the light receiving surface optical axis Ars of the scattered light optical fiber cable <NUM>. The sleeve <NUM> of the heating optical fiber cable <NUM> is attached to each of the plurality of light shielding members 50a, as in the first embodiment. The heating laser oscillator <NUM> is connected to each heating optical fiber cable <NUM>.

As described above, one light shielding member may be provided or a plurality of light shielding members may be provided.

Also, in this embodiment, the laser emission window <NUM> and the laser receiving window <NUM> are in contact with the scattered light window 42a. Thus, if the scattered light window 42a is heated using the energy of the laser light oscillated from the heating laser oscillator <NUM>, the emission prism <NUM> and the light receiving prism <NUM> are also heated. For this reason, it is possible to remove foreign matter in the fluid G adhered to the emission surface 23o of the emission prism <NUM> and the incident surface 33i of the light receiving prism <NUM> and to prevent adhering of foreign matter to the emission surface 23o of the emission prism <NUM> and the incident surface 33i of the light receiving prism <NUM>.

In the embodiment described above, the fact that B is perpendicular to A means not only that an angle of B with respect to A is <NUM>° but also that the angle of B with respect to A is about <NUM>° to <NUM>° and B is substantially perpendicular to A. Furthermore, the fact that A and B are parallel to each other means not only that an angle of B with respect to A is <NUM>° but also that the angle of B with respect to A is about -<NUM>° to +<NUM>° and B is substantially parallel to A.

In the above embodiment, the laser light receiving optical system (the excitation light receiving optical system) <NUM> or 31a has the condensing optical system <NUM>. However, if an intensity of the laser light incident on the laser light receiving optical system <NUM> is not extremely smaller than an intensity of the laser light from the analyzing laser oscillator <NUM> which is a light emission unit, the condensing optical system <NUM> may be omitted.

The laser light receiving optical system (the excitation light receiving optical system) <NUM> or 31a in the above embodiment is an optical system provided for determining an abnormality of the scattered light acquisition head <NUM>. Thus, when it is not necessary to determine an abnormality of the scattered light acquisition head <NUM>, the laser light receiving optical system (the excitation light receiving optical system) <NUM> or 31a may be omitted.

The changer in the above embodiment is the emission prism <NUM> or the light receiving prism <NUM>. However, the changer may be a mirror.

The scattered light receiving device <NUM> in the above embodiment does not have a condensing optical system. However, the scattered light receiving device <NUM> may have a condensing optical system.

The fluid G to be analyzed in the above embodiment is a gas G which is unmixed BFG. However, the fluid G to be analyzed may be unmixed COG, a mixture of a BFG and a COG, or a mixture of a BFG, a COG, and a LDG. Furthermore, the fluid G to be analyzed may be another fuel gas, for example, natural gas, biogas, or the like. In addition, the fluid G to be analyzed may not be a fuel gas.

Claim 1:
A Raman scattered light acquisition device (<NUM>), comprising:
an emission optical system (<NUM>, 21a) which is configured to guide excitation light from a light emission unit (<NUM>) into a fluid (G) along an optical axis (Aw);
a scattered light window (<NUM>, 42a) which is configured to define a part of a flow path of the fluid (G) and through which Raman scattered light from the fluid (G) irradiated with the excitation light passes;
a scattered light receiving device (<NUM>) which has a light receiving surface (<NUM>) receiving the Raman scattered light which has passed through the scattered light window (<NUM>, 42a);
wherein the scattered light window (<NUM>, 42a) and the light receiving surface (<NUM>) of the scattered light receiving device (<NUM>) are arranged at positions in which the scattered light window (<NUM>, 42a) and the light receiving surface (<NUM>) are separated from the optical axis (Aw) in the fluid (G) in a radial direction (Dr) which is a direction perpendicular to the optical axis (Aw) in the fluid (G) within a range in which an optical path of the excitation light in the fluid (G) is present in an optical axis direction (Da) in which the optical axis (Aw) in the fluid (G) which is the optical axis of the excitation light in the fluid (G) extends,
the light receiving surface (<NUM>) faces a radially inward side (Dri) which is a side in proximity to the optical axis (Aw) in the fluid (G) in the radial direction (Dr),
characterized in that the Raman scattered light acquisition device (<NUM>) further comprises
a light shielding member (<NUM>,50a) through which the excitation light and the Raman scattered light do not pass, wherein
the light shielding member (<NUM>, 50a) is in contact with an outer surface (42o) of the scattered light window (<NUM>, 42a) on the light receiving surface (<NUM>) side,
a heating optical fiber cable (<NUM>) arranged to irradiate the light shielding member (<NUM>,50a) with heating laser light;
a cavity (<NUM>) which extends along the outer surface (42o) of the scattered light window (<NUM>, 42a) is formed inside the light shielding member (<NUM>, 50a),
wherein the heating optical fiber cable (<NUM>) is configured to emit into the cavity (<NUM>) of the light shielding member (<NUM>, 50a).