JP2005195354A - Instrument and method for measuring oxygen concentration - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem wherein a fluorescent type oxygen densitometer generates an error in a calculated oxygen concentration in accompaniment to deterioration of an oxygen quenching substance. <P>SOLUTION: Light from a light source 20 is emitted from a tip part of an excitation light transmitting optical fiber 42. The irradiation light excites an oxygen quenching substance provided in a tip part of an optical fiber 44 for detection and an oxygen quenching substance provided in a tip part of a optical fiber 46 for calibration, to emit fluorescent lights. The oxygen quenching substance provided in the tip part of the optical fiber 46 for the calibration is coated with an oxygen shielding member to be kept in a condition of 0% of oxygen concentration. The emission lights from the oxygen quenching substances provided in the tip part of the optical fiber 44 for the detection and the tip part of the optical fiber 46 for the calibration are amplified and digitalized by an amplifying circuit 60 and an A/D circuit 70 to obtain respective brightness values. A calibration curve for calculating the oxygen concentration is corrected using the brightness value of the oxygen quenching substance provided in the tip part of the optical fiber 46 for the calibration. The oxygen concentration corresponding to the brightness value in the the tip part of the optical fiber 44 for the detection is calculated based on the corrected calibration curve. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an apparatus and method for measuring oxygen concentration. In particular, the present invention relates to an apparatus and method for measuring oxygen concentration based on the brightness of an oxygen quenching substance.

  Conventionally, a fluorescent oxygen concentration meter using a quenching action of fluorescent light emission by oxygen is known. When a fluorescent material having polycyclic aromatics or aromatic hydrocarbons is irradiated with light, it emits fluorescence. In the presence of oxygen molecules, the excited fluorescent molecules react to form a complex temporarily, and a quenching phenomenon occurs in proportion to the collision probability between the oxygen molecules and the fluorescent molecules. The fluorescence oxygen concentration meter obtains the oxygen concentration by utilizing this quenching phenomenon. More specifically, the luminance ratio (I0 / I) is linearly proportional to the oxygen concentration (partial pressure), where I0 and I are the luminances of fluorescence in an oxygen-free state and an aerobic state. Therefore, the oxygen concentration can be obtained by measuring this relative luminance.

  For example, Japanese Patent Application Laid-Open No. 2002-529682 discloses a technique for measuring an oxygen concentration by applying an oxygen quenching substance to the tip of an optical fiber.

JP 2002-529682 A

  Oxygen-quenching substances (fluorescent substances containing polycyclic aromatics and aromatic hydrocarbons) degrade with the passage of time and the fluorescence brightness decreases, so the oxygen concentration is calculated based on the relationship between the default brightness and the oxygen concentration. Then an error occurs. Since the deterioration of the oxygen quenching substance progresses as time elapses, it is difficult to measure the oxygen concentration over a long period of time.

  Moreover, since the fluorescence characteristics of the oxygen quenching substance change depending on the temperature, an error due to a temperature difference occurs when the oxygen concentration is calculated based on the relationship between a predetermined luminance and the oxygen concentration.

  Therefore, an object of the present invention is to improve the measurement accuracy in measuring the oxygen concentration based on the luminance of the fluorescence emission of the oxygen quenching substance. Another object of the present invention is to measure the oxygen concentration in real time over a long period of time based on the luminance of fluorescence emission of the oxygen quenching substance.

  In one embodiment of the present invention, a measurement light-emitting part made of an oxygen-quenching substance whose emission intensity changes according to the oxygen concentration, and an oxygen-quenching substance provided in the vicinity of the measurement light-emitting part and from which oxygen is blocked A calibration light emitting unit, a light emitting unit for emitting excitation light of an oxygen quenching substance to the measurement light emitting unit and the calibration light emitting unit, and a measurement luminance for measuring the luminance of the measurement light emitting unit Using the relationship between the measurement unit, the calibration luminance measurement unit that measures the luminance of the calibration light-emitting unit, and the luminance and oxygen concentration of the oxygen quenching substance obtained based on the luminance of the calibration light-emitting unit, And an arithmetic unit that calculates the oxygen concentration from the luminance of the light emitting unit for measurement.

  In an aspect of the present invention, the measurement light-emitting unit, the calibration light-emitting unit, and the light irradiation unit are provided at the tip of an optical fiber, and the measurement luminance measurement unit and the calibration luminance measurement unit are You may measure the brightness | luminance of light from the said measurement light emission part and the said calibration light emission part transmitted with the optical fiber, respectively.

  In an aspect of the present invention, the light irradiation unit is provided at a tip of an optical fiber, the measurement light emitting unit and the calibration light emission unit are provided on a target object, and the measurement luminance measurement unit and the measurement light emitting unit are provided. The calibration luminance measuring unit may measure the luminance of light from the measurement light emitting unit and the calibration light emitting unit transmitted by the optical fiber.

  Further, in another aspect of the present invention, a measurement light-emitting unit made of an oxygen quenching substance whose emission intensity changes according to the oxygen concentration, a temperature detection unit provided in the vicinity of the measurement light-emitting unit, Based on a temperature obtained by the light irradiation unit that emits the excitation light of the oxygen quenching substance to the measurement light-emitting unit, the measurement luminance measurement unit that measures the luminance of the measurement light-emitting unit, and the temperature detection unit And a calculation unit that calculates the oxygen concentration from the luminance of the measurement light-emitting unit using the relationship between the luminance and oxygen concentration of the oxygen quenching substance obtained in this manner.

  In another aspect of the present invention, the measurement light-emitting unit and the temperature detection unit are provided at the tip of an optical fiber, and the measurement luminance measurement unit is connected to the measurement light-emitting unit transmitted by the optical fiber. You may measure the brightness | luminance of the brightness of this light.

  In another aspect of the present invention, the light irradiation unit is provided at a tip of an optical fiber, the measurement light emitting unit and the temperature detection unit are provided on a target object, and the measurement luminance measurement unit and the measurement The temperature detection unit may measure the luminance of light from the measurement light emitting unit transmitted by the optical fiber.

  In another aspect of the present invention, a measurement light-emitting part made of an oxygen quenching substance whose emission intensity changes according to the oxygen concentration, and a brightness at a predetermined oxygen concentration are provided in the vicinity of the measurement light-emitting part. A first calibration light-emitting portion made of an oxygen-quenching substance, and a second calibration light-emitting material made in the vicinity of the measurement light-emitting portion and made of an oxygen-quenching material that exhibits luminance at a predetermined oxygen concentration different from the predetermined oxygen concentration A light emitting unit, a light emitting unit that emits excitation light of an oxygen quenching substance to the measurement light emitting unit, the first calibration light emitting unit, and the second calibration light emitting unit, and the luminance of the measurement light emitting unit Brightness measuring unit for measuring, a first calibration brightness measuring unit for measuring the brightness of the first calibration light emitting unit, and a second calibration brightness measuring unit for measuring the brightness of the first calibration light emitting unit The first calibration light emitting unit and the second A calculation unit that calculates the oxygen concentration from the luminance of the light emitting unit for measurement using the relationship between the luminance of the oxygen quenching substance obtained based on the luminance of the main light emitting unit and the oxygen concentration. To do.

  In another aspect of the present invention, the measurement light-emitting unit, the first calibration light-emitting unit, the second calibration light-emitting unit, and the light irradiation unit are provided at the tip of an optical fiber, and the measurement luminance measurement Unit, the first calibration luminance measurement unit, and the second calibration luminance measurement unit from the measurement light emission unit, the first calibration light emission unit, and the second calibration light emission unit transmitted by the optical fiber. You may measure the brightness | luminance of light, respectively.

  In another aspect of the present invention, the light irradiation unit is provided at a tip of an optical fiber, and the measurement light-emitting unit, the first calibration light-emitting unit, and the second calibration light-emitting unit are on a target object. The measurement luminance measurement unit, the first calibration luminance measurement unit, and the second calibration luminance measurement unit, the measurement light emission unit transmitted by the optical fiber, the first calibration light emission unit, and You may measure the brightness | luminance of light from the said 2nd light emission part for a calibration, respectively.

  In another aspect of the present invention, the step of irradiating the oxygen quenching substance provided at the tip of the optical fiber with excitation light and the brightness of the region facing the oxygen-containing gas in the oxygen quenching substance And measuring the luminance of the oxygen-quenched substance in the region where oxygen is blocked using an optical fiber, and the oxygen quenching substance obtained based on the luminance of the region where oxygen is blocked And a step of calculating the oxygen concentration from the luminance of the region through which oxygen passes using the relationship between the luminance and the oxygen concentration.

  In another aspect of the present invention, a step of irradiating an oxygen quenching substance provided on a target object with excitation light and a luminance optical fiber in a region facing the oxygen-containing gas in the oxygen quenching substance are used. Measuring the brightness of the oxygen-quenched substance in the area where oxygen is blocked using an optical fiber, and the oxygen quenching substance obtained based on the brightness of the area where oxygen is blocked. And a step of calculating the oxygen concentration from the luminance of the region through which oxygen passes using the relationship between the luminance and the oxygen concentration.

  According to another aspect of the present invention, the method includes a step of calculating an oxygen concentration from luminance of a region through which oxygen passes.

  In another aspect of the present invention, a step of irradiating an oxygen quenching substance provided at the tip of the optical fiber with excitation light, a step of measuring the brightness of the oxygen quenching substance using an optical fiber, and an oxygen quenching Measuring the temperature in the vicinity of the active substance, calculating the oxygen concentration from the brightness of the oxygen quenching substance using the relationship between the brightness of the oxygen quenching substance obtained based on the measured temperature and the oxygen concentration, and It is characterized by providing.

  In another aspect of the present invention, the step of irradiating the oxygen quenching substance provided on the target object with excitation light, the step of measuring the brightness of the oxygen quenching substance using an optical fiber, and the oxygen quenching Measuring the temperature in the vicinity of the active substance, calculating the oxygen concentration from the brightness of the oxygen quenching substance using the relationship between the brightness of the oxygen quenching substance obtained based on the measured temperature and the oxygen concentration, and It is characterized by providing.

  In another aspect of the present invention, the step of irradiating the oxygen quenching substance provided at the tip of the optical fiber with excitation light and the brightness of the region facing the oxygen-containing gas in the oxygen quenching substance The step of measuring using, the step of measuring the luminance of the region facing the first predetermined concentration of oxygen in the oxygen quenching substance using an optical fiber, and the first predetermined concentration of the oxygen quenching substance A step of measuring, using an optical fiber, a luminance of a region facing a different second predetermined concentration of oxygen, a luminance of a region facing the first predetermined concentration of oxygen, and a region facing the second predetermined concentration of oxygen; And a step of calculating the oxygen concentration from the luminance of the region through which oxygen permeates using the relationship between the luminance of the oxygen quenching substance obtained based on the luminance and the oxygen concentration.

  In another aspect of the present invention, the step of irradiating the oxygen quenching substance provided on the object with excitation light, and the brightness of the region facing the oxygen-containing gas in the oxygen quenching substance are controlled by an optical fiber. The step of measuring using, the step of measuring the brightness of the region facing the first predetermined concentration of oxygen in the oxygen quenching substance using an optical fiber, and the first predetermined concentration of the oxygen quenching substance. A step of measuring, using an optical fiber, a luminance of a region facing a different second predetermined concentration of oxygen, a luminance of a region facing the first predetermined concentration of oxygen, and a region facing the second predetermined concentration of oxygen; And a step of calculating the oxygen concentration from the luminance of the region through which oxygen permeates using the relationship between the luminance of the oxygen quenching substance obtained based on the luminance and the oxygen concentration.

  According to the present invention, the oxygen concentration is measured based on the fluorescence emission luminance of the oxygen quenching substance in consideration of the deterioration characteristics of the oxygen quenching substance, so that the measurement accuracy is improved.

  In addition, according to the present invention, the oxygen concentration is measured based on the fluorescence emission luminance of the oxygen quenching substance in consideration of the temperature dependence of the oxygen quenching substance, so that the measurement accuracy is improved.

  Further, according to the present invention, since the relationship between the luminance of the fluorescence emission of the oxygen quenching substance and the oxygen concentration is sequentially obtained by two-point correction, the measurement accuracy is improved in the measurement environment.

  In addition, according to the present invention, the oxygen concentration can be measured over a long time in real time.

  Hereinafter, the present invention will be described through embodiments of the invention.

  FIG. 1 shows a configuration of an oxygen concentration measuring apparatus 10 according to the embodiment. The oxygen concentration measuring apparatus 10 includes a light source 20, a control unit 30, an optical fiber bundle 40, an optical sensor 50, an amplification circuit 60, an A / D conversion circuit 70, a data storage unit 72, and a calculation unit 80.

  The light source 20 emits light having an excitation wavelength of an oxygen quenching substance used in the measurement light emitting unit 100 and the calibration light emitting unit 102 described later. A typical example of the light source 20 is a xenon lamp or a metal halide lamp provided with a blue LED having a wavelength of 460 nm and an optical filter having a wavelength of 460 nm. The light emission timing of the light source 20 is controlled by the control unit 30.

  The optical fiber bundle 40 includes an excitation light transmission optical fiber 42, a light emission detection optical fiber 44, and a calibration optical fiber 46. FIG. 2 is a perspective view of the tip portion of the optical fiber bundle 40. FIG. 3 is a cross-sectional view of the distal end portion of the optical fiber bundle 40. The pumping light transmission optical fiber 42 is disposed concentrically inside the coating 41. The light emission detection optical fiber 44 and the calibration optical fiber 46 are arranged so as to bisect the region inside the pumping light transmission optical fiber 42.

  The pumping light transmission optical fiber 42 includes a plurality of optical fibers connected to the light source 20, and transmits light emitted from the light source 20. The light transmitted by the pumping light transmission optical fiber 42 is projected from the tip of the optical fiber bundle 40.

  The light emission detecting optical fiber 44 is composed of a plurality of optical fibers connected to the optical sensor 50, and the measurement light emitting unit 100 is applied to the tip portion. The measurement light emitting unit 100 is made of an oxygen quenching substance such as a ruthenium porphyrin complex having a film thickness of 1 μm to several tens of μm. The oxygen quenching substance in the measurement light emitting unit 100 is excited by light projected from the tip of the optical fiber bundle 40 and emits fluorescent light. The light emitted from the measurement light emitting unit 100 passes through the light emission detection optical fiber 44 and reaches the optical sensor 50.

  The calibration optical fiber 46 is composed of a plurality of optical fibers connected to the optical sensor 50, the calibration light emitting unit 102 is applied to the tip, and the oxygen blocking member 104 is attached on the surface of the calibration light emitting unit 102. It has been. The oxygen blocking member 104 is an oxygen-impermeable material, and for example, a glass flat plate or an acrylic plate can be used. The calibration light emitting unit 102 is made of an oxygen quenching substance having a film thickness of 1 μm to several tens of μm, which is the same as the measurement light emitting unit 100. The oxygen quenching substance in the calibration light emitting unit 102 is excited by light projected from the tip of the optical fiber bundle 40 and emits fluorescence. The light emitted from the calibration light emitting unit 102 reaches the optical sensor 50 through the calibration optical fiber 46.

  With the above configuration, the calibration light-emitting unit 102 is kept in a state where the oxygen concentration is zero because oxygen in the outside air is blocked by the oxygen blocking member 104. Therefore, the oxygen quenching substance of the calibration light emitting unit 102 exhibits fluorescence characteristics in a state where the oxygen concentration is zero.

  The optical sensor 50 detects light transmitted by the light emission detection optical fiber 44 and the calibration optical fiber 46. A specific example of the optical sensor 50 is a photoelectric conversion element such as a photodiode or a CCD.

  The optical sensor 50 converts the detected light into an electrical signal and outputs it. The output electric signal is amplified by the amplifier circuit 60. The electric signal amplified by the amplification circuit 60 is converted into digital data by the A / D conversion circuit 70 and sent to the calculation unit 80 as the luminance value of the measurement light emitting unit 100 or the calibration light emitting unit 102.

  The optical sensor 50 may simultaneously detect light from the light emission detection optical fiber 44 and the calibration optical fiber 46 by separate photodiodes or the like, and detect by using one photodiode or the like by switching the detection timing. May be. When a CCD is used as the optical sensor 50, the light emission states of the measurement light emitting unit 100 and the calibration light emitting unit 102 can be imaged.

  The data storage unit 72 stores in advance data relating to the relationship between the oxygen concentration and the luminance value used for oxygen concentration calculation. The data relating to the relationship between the oxygen concentration and the luminance value is, for example, a calibration line indicating the oxygen concentration dependency of the luminance value.

  FIG. 4 is a graph showing a calibration line 200 for calculating the oxygen concentration. Using this calibration line 200, the oxygen concentration corresponding to the luminance value can be obtained. However, when the oxygen concentration is calculated using the calibration line 200, the deterioration characteristics of the oxygen quenching substance are not taken into consideration. The calibration line 200 in FIG. 4 indicates, for example, the luminance value (coordinate A) of the measurement light emitting unit 100 in the atmosphere (oxygen concentration 20.8%) and the oxygen concentration measuring device 10 during assembly or inspection before shipment. It is obtained by acquiring the luminance value (coordinate B) of the calibration light emitting unit 102.

  The computing unit 80 calculates the oxygen concentration using the input luminance values of the measurement light emitting unit 100 and the calibration light emitting unit 102 and the calibration line stored in the data storage unit 72. Below, the procedure of oxygen concentration calculation is described using the flowchart of FIG.

  First, the luminance value Ia of the measurement light emitting unit 100 is acquired (S10). The luminance value Ib of the calibration light emitting unit 102 is acquired simultaneously with or before the acquisition of the luminance value Ia (S20).

  The verification line is corrected using the luminance value Ib (S30). FIG. 6 is a diagram illustrating a method for correcting the verification line. The corrected calibration line 210 has the same slope as that of the calibration line 200 before correction, and passes the coordinates C (oxygen concentration zero, luminance value Ib). The calibration line 210 shows the oxygen concentration dependence of the luminance value when the luminance value Ia is acquired.

  Based on the calibration line 210, the oxygen concentration corresponding to the luminance value Ia is calculated (S40). By calculating the oxygen concentration using the calibration line 210, it is possible to take into account the deterioration characteristics (change over time) of the oxygen quenching substance, and to calculate the oxygen concentration more accurately. In addition, it is possible to measure the oxygen concentration taking into account the deterioration characteristics of the oxygen quenching substance over a long period of time in real time. As an application example of the oxygen concentration measuring apparatus 10, oxygen concentration measurement in a fuel cell, a turbo, an engine cylinder, or the like is conceivable.

  In addition, the front-end | tip part of the optical fiber bundle 20 of this embodiment is not restricted to the structure of FIG. For example, as shown in FIG. 7, a U-shaped (concave) oxygen blocking member 104 is pasted on the calibration light emitting unit 102, and the space between the oxygen blocking member 104 and the calibration light emitting unit 102 is attached. An oxygen scavenger 112 that absorbs oxygen may be provided. As the oxygen scavenger 112, for example, iron powder that absorbs oxygen using an oxidation reaction of iron can be used. According to this, it is possible to more effectively prevent oxygen from entering the calibration light-emitting unit 102 and to calculate the oxygen concentration more accurately.

  FIG. 8 shows a configuration of an oxygen concentration measuring device 12 according to another embodiment. In the description of the oxygen concentration measuring device 12, the same configuration as that of the oxygen concentration measuring device 10 is omitted as appropriate.

  The optical fiber bundle 300 of the oxygen concentration measuring apparatus 12 includes a temperature acquisition optical fiber 310 instead of the calibration optical fiber 46 shown in FIG. As shown in FIG. 9, a temperature display unit 312 that displays the temperature is provided at the tip of the temperature acquisition optical fiber 310. As the temperature display unit 312, for example, a temperature-sensitive liquid crystal whose reflected light spectrum is changed by a cholesteric effect can be used. The light of the temperature display unit 312 is transmitted to the optical sensor 50 through the temperature acquisition optical fiber 310. A CCD is used as the optical sensor 50, and the color of the temperature display unit 312 is imaged.

  The data storage unit 72 stores in advance data related to the relationship between the oxygen concentration and the luminance value used for calculating the oxygen concentration taking temperature dependence into consideration. The data relating to the relationship between the oxygen concentration and the luminance value in consideration of the temperature dependency is, for example, a calibration line indicating the oxygen concentration dependency of the luminance value at each temperature of 1 ° C. from 0 to 300 ° C. By using the calibration line corresponding to each temperature, the oxygen concentration according to the temperature of the tip portion of the optical fiber bundle 300 can be obtained.

  The calculation unit 80 calculates the oxygen concentration using the luminance value of the measurement light emitting unit 100, the image of the temperature display unit 312, and the calibration line stored in the data storage unit 72. The procedure for calculating the oxygen concentration will be described below using the flowchart of FIG.

  First, the luminance value Ia of the measurement light emitting unit 100 is acquired (S100). Further, the temperature of the temperature display unit 312 is calculated based on the image of the temperature display unit 312 (S110).

  A calibration line corresponding to the calculated temperature is read from the data storage unit 72 (S120).

  Based on the read calibration line, the oxygen concentration corresponding to the luminance value Ia is calculated (S130). Thus, by calculating the oxygen concentration using the calibration line set for each temperature, the temperature characteristics of the oxygen quenching substance can be taken into account, and the oxygen concentration can be calculated more accurately.

  Note that the method of measuring the temperature at the tip of the optical fiber bundle 300 is not limited to the above configuration. For example, the temperature of the front end portion of the optical fiber bundle 300 can also be measured by providing a thermocouple at the front end portion of the optical fiber bundle 300.

  FIG. 11 shows a configuration of an oxygen concentration measurement device 14 according to still another embodiment.

  The optical fiber bundle 400 of the oxygen concentration measuring device 14 includes a first calibration optical fiber 410 and a second calibration optical fiber 420 instead of the calibration optical fiber 46 illustrated in FIG.

  12 shows a perspective view of the tip end of the optical fiber bundle 400, and FIG. 13 shows a configuration of the first calibration optical fiber 410 and the second calibration optical fiber 420 side in the AA cross section in FIG. A first calibration light emitting unit 430 is provided at the distal end of the first calibration optical fiber 410, and an oxygen blocking member 440 is provided on the first calibration light emitting unit 430. In addition, a second calibration light emitting unit 450 is provided at the tip of the second calibration optical fiber 420, and a U-shaped (concave) oxygen blocking member 460 is disposed on the second calibration light emitting unit 450. Is provided. In the space 470 between the oxygen blocking member 460 and the second calibration light emitting unit 450, atmospheric pressure and oxygen having a concentration of 20.8% are held in a sealed state.

  The computing unit 80 calculates the oxygen concentration based on the luminance value of the measurement light emitting unit 100, the luminance value of the first calibration light emitting unit 430, and the luminance value of the second calibration light emitting unit 450. Below, the procedure of oxygen concentration calculation is described using the flowchart of FIG.

  First, the luminance value of the measurement light emitting unit 100 is acquired (S200). The brightness values of the first calibration light-emitting unit 430 and the second calibration light-emitting unit 450 are acquired at the same time as or after the acquisition of the brightness value (S210).

  A calibration line is created using the luminance values of the first calibration light emission unit 430 (oxygen concentration 0%) and the second calibration light emission unit 450 (oxygen concentration 20.8%) (S220).

  FIG. 15 is a diagram showing a test line obtained by two-point correction. The calibration line 500 is obtained by connecting a luminance value (coordinate E) with an oxygen concentration of 0% and a luminance value (coordinate D) with an oxygen concentration of 20.8% obtained at a certain time. The calibration line 510 after a predetermined time has elapsed is obtained by connecting the newly acquired luminance value (coordinate G) with an oxygen concentration of 0% and the luminance value (coordinate F) with an oxygen concentration of 20.8%. As described above, since luminance values with an oxygen concentration of 20.8% and an oxygen concentration of 0% are obtained at an arbitrary time, a calibration line for calculating an oxygen concentration adapted to a deteriorated oxygen quenching substance is sequentially obtained.

  Based on the created calibration line, the oxygen concentration corresponding to the luminance value of the measurement light emitting unit 100 is calculated (S230).

  As described above, since the calibration line for calculating the oxygen concentration adapted to the deteriorated oxygen quenching substance is sequentially created, it is possible to calculate the oxygen concentration more accurately without preparing the calibration line in advance.

  Note that the first calibration light-emitting unit 430 and the second calibration light-emitting unit 450 only have to face different known concentrations of oxygen, and the oxygen concentration in the space 470 is not limited to 20.8%, but any concentration. Can be set to The first calibration light emitting unit 430 may also face a predetermined concentration of oxygen in the sealed space, like the second calibration light emitting unit 450.

  In the embodiments described above, a measurement light-emitting unit, a calibration light-emitting unit, a temperature display unit, and the like are provided at the tip of the optical fiber bundle, but instead of such a configuration, for example, MEA A light-emitting unit for measurement, a light-emitting unit for calibration, a temperature display unit, and the like can be provided on an object such as (membrane electrode assembly).

  FIG. 16 is a diagram showing a configuration (oxygen concentration measuring device 16) in the case where the measurement light emitting unit and the like of the oxygen concentration measuring device 14 are provided on the MEA 600.

  On the MEA 600, a measurement light emitting unit 610, a first calibration light emitting unit 620, and a second calibration light emitting unit 630 are provided. The first calibration light emitting unit 620 is covered with an oxygen blocking member (not shown) as in the first calibration light emitting unit 430 of FIG. In addition, a U-shaped (concave) oxygen blocking member (not shown) is provided on the second calibration light-emitting unit 630, similarly to the second calibration light-emitting unit 450 of FIG. Between the 630 and the oxygen blocking member, atmospheric pressure and oxygen with a concentration of 20.8% are sealed.

  The tip of the optical fiber bundle 400 is positioned on the measurement light emitting unit 610, the first calibration light emitting unit 620, and the second calibration light emitting unit 630, and the excitation light transmitting optical fiber 42 includes the measurement light emitting unit 610, The first calibration light emitting unit 620 and the second calibration light emitting unit 630 are irradiated with excitation light.

  The measurement light emitting unit 610, the first calibration light emitting unit 620, and the second calibration light emitting unit 630 pass through the light emission detecting optical fiber 44, the first calibration optical fiber 410, and the second calibration optical fiber 420 to obtain an image. And the respective luminance values are obtained.

  Using the luminance values of the measurement light-emitting unit 610, the first calibration light-emitting unit 620, and the second calibration light-emitting unit 630, the oxygen concentration is calculated in the same procedure as the flowchart of FIG.

  This makes it possible to directly and accurately measure the oxygen concentration of the target object such as the MEA surface. Further, by accurately measuring the oxygen concentration on the surface of the MEA in real time, it is possible to perform feedback control on the input pressure and input flow rate of the fuel gas (oxygen / air).

  In the oxygen concentration measuring device 16 of FIG. 16, the light emission detecting optical fiber 44, the first calibration optical fiber 410, and the second calibration optical fiber 420 are used for each light emitting portion as the light emission detecting optical fiber. However, the measurement light emitting unit 610, the first calibration light emitting unit 620, and the second calibration light emitting unit 630 may be imaged as a whole image using a common optical fiber, and the luminance value may be obtained from the image corresponding to each region. .

It is a figure showing composition of oxygen concentration measuring device 10 concerning an embodiment. It is a perspective view of the optical fiber bundle 40 front-end | tip part. It is sectional drawing of the optical fiber bundle 40 front-end | tip part. It is a graph which shows the calibration line 200 for oxygen concentration calculation. 3 is a flowchart showing a procedure for calculating an oxygen concentration in the oxygen concentration measuring apparatus 10. It is a figure which shows the correction method of a test line. It is a figure which shows the other structure of the front-end | tip part of the optical fiber bundle 40. FIG. It is a figure which shows the structure of the oxygen concentration measuring device 12 which concerns on other embodiment. FIG. 4 is a cross-sectional view of the distal end portion of an optical fiber bundle 300 of the oxygen concentration measuring device 12. 4 is a flowchart showing a procedure for calculating an oxygen concentration in the oxygen concentration measuring device 12. It is a figure which shows the structure of the oxygen concentration measuring apparatus 14 which concerns on other embodiment. It is a perspective view of the optical fiber bundle 400 tip. It is a figure which shows the structure by the side of the 1st calibration optical fiber 410 and the 2nd calibration optical fiber 420 of the AA cross section in FIG. 3 is a flowchart showing a procedure for calculating oxygen concentration in an oxygen concentration measuring device 14; It is a figure which shows the verification line obtained by 2 point | piece correction. The structure (oxygen concentration measuring device 16) when the light emission part for measurement of the oxygen concentration measuring device 14 etc. are provided on MEA600 is shown.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Oxygen concentration measuring device, 20 Light source, 30 Control part, 40 Optical fiber bundle, 50 Optical sensor, 60 Amplification circuit, 70 A / D conversion circuit, 80 calculating part.

Claims (15)

A light-emitting portion for measurement made of an oxygen-quenching substance whose emission intensity changes according to the oxygen concentration;
A calibration light-emitting part that is provided in the vicinity of the measurement light-emitting part and is made of an oxygen quenching substance in which oxygen is blocked;
A light irradiation unit that emits excitation light of an oxygen quenching substance to the measurement light-emitting unit and the calibration light-emitting unit;
A measurement luminance measurement unit for measuring the luminance of the measurement light emitting unit;
A calibration luminance measuring unit for measuring the luminance of the calibration light emitting unit;
A calculation unit that calculates the oxygen concentration from the luminance of the light emitting unit for measurement, using the relationship between the luminance of the oxygen quenching substance obtained based on the luminance of the light emitting unit for calibration and the oxygen concentration,
An oxygen concentration measuring device comprising: The measurement light emitting unit, the calibration light emitting unit and the light irradiation unit are provided at the tip of an optical fiber,
The measurement luminance measurement unit and the calibration luminance measurement unit respectively measure the luminance of light from the measurement light emission unit and the calibration light emission unit transmitted by the optical fiber. The oxygen concentration measuring device described. The light irradiation unit is provided at the tip of an optical fiber;
The measurement light emitting unit and the calibration light emitting unit are provided on a target object,
The measurement luminance measurement unit and the calibration luminance measurement unit respectively measure the luminance of light from the measurement light emission unit and the calibration light emission unit transmitted by the optical fiber. The oxygen concentration measuring device described. A light-emitting portion for measurement made of an oxygen-quenching substance whose emission intensity changes according to the oxygen concentration;
A temperature detection unit provided in the vicinity of the measurement light-emitting unit;
A light irradiation unit that emits excitation light of an oxygen quenching substance to the measurement light-emitting unit;
A measurement luminance measurement unit for measuring the luminance of the measurement light emitting unit;
A calculation unit that calculates the oxygen concentration from the luminance of the light emitting unit for measurement, using the relationship between the luminance of the oxygen quenching substance obtained based on the temperature obtained by the temperature detection unit and the oxygen concentration,
An oxygen concentration measuring device comprising: The measurement light emitting part and the temperature detection part are provided at the tip of an optical fiber,
The oxygen concentration measuring device according to claim 4, wherein the measurement luminance measurement unit measures the luminance of light from the measurement light emitting unit transmitted by the optical fiber. The light irradiation part is provided at the tip of an optical fiber,
The measurement light emitting unit and the temperature detection unit are provided on a target object,
The oxygen concentration measurement apparatus according to claim 1, wherein the measurement luminance measurement unit and the temperature detection unit measure light luminance from the measurement light-emitting unit transmitted by the optical fiber. A light-emitting portion for measurement made of an oxygen-quenching substance whose emission intensity changes according to the oxygen concentration;
A first calibration light-emitting part that is provided in the vicinity of the measurement light-emitting part and is made of an oxygen quenching substance that exhibits luminance at a predetermined oxygen concentration;
A second calibration light-emitting part made of an oxygen quenching substance provided in the vicinity of the measurement light-emitting part and having a luminance at a predetermined oxygen concentration different from the predetermined oxygen concentration;
A light irradiation unit that emits excitation light of an oxygen quenching substance to the measurement light-emitting unit, the first calibration light-emitting unit, and the second calibration light-emitting unit;
A measurement luminance measurement unit for measuring the luminance of the measurement light emitting unit;
A first calibration luminance measuring unit for measuring the luminance of the first calibration light emitting unit;
A second calibration luminance measuring unit for measuring the luminance of the first calibration light emitting unit;
The oxygen concentration is calculated from the luminance of the measurement light emitting unit using the relationship between the luminance and the oxygen concentration of the oxygen quenching substance obtained based on the luminance of the first calibration light emitting unit and the second calibration light emitting unit. An arithmetic unit to perform,
An oxygen concentration measuring device comprising: The measurement light emitting unit, the first calibration light emitting unit, the second calibration light emitting unit, and the light irradiation unit are provided at the tip of an optical fiber,
The measurement luminance measurement unit, the first calibration luminance measurement unit, and the second calibration luminance measurement unit are configured to transmit the measurement light emission unit, the first calibration light emission unit, and the second calibration light transmitted by the optical fiber, respectively. The oxygen concentration measuring apparatus according to claim 7, wherein the brightness of light is measured from each of the calibration light emitting units. The light irradiation unit is provided at the tip of an optical fiber;
The measurement light-emitting unit, the first calibration light-emitting unit, and the second calibration light-emitting unit are provided on a target object,
The measurement luminance measurement unit, the first calibration luminance measurement unit, and the second calibration luminance measurement unit are configured to transmit the measurement light emission unit, the first calibration light emission unit, and the second calibration light transmitted by the optical fiber, respectively. The oxygen concentration measuring apparatus according to claim 7, wherein the brightness of light is measured from each of the calibration light emitting units. Irradiating an oxygen quenching substance provided at the tip of the optical fiber with excitation light;
A step of measuring the brightness of the region facing the oxygen-containing gas in the oxygen quenching substance using an optical fiber;
A step of measuring the brightness of the oxygen-quenched substance in a region where oxygen is blocked using an optical fiber;
Calculating the oxygen concentration from the luminance of the region through which oxygen passes, using the relationship between the luminance of the oxygen quenching substance obtained based on the luminance of the region where oxygen is blocked and the oxygen concentration; and
An oxygen concentration measurement method comprising: Irradiating an oxygen quenching substance provided on a target object with excitation light;
A step of measuring the oxygen quenching substance using a luminance optical fiber in a region facing the oxygen-containing gas;
A step of measuring the brightness of the oxygen-quenched substance in a region where oxygen is blocked using an optical fiber;
Calculating the oxygen concentration from the luminance of the region through which oxygen passes, using the relationship between the luminance of the oxygen quenching substance obtained based on the luminance of the region where oxygen is blocked and the oxygen concentration; and
An oxygen concentration measurement method comprising: Irradiating an oxygen quenching substance provided at the tip of the optical fiber with excitation light;
Measuring the brightness of the oxygen quenching substance using an optical fiber;
Measuring the temperature in the vicinity of the oxygen quenching substance;
Calculating the oxygen concentration from the brightness of the oxygen quenching substance using the relationship between the brightness of the oxygen quenching substance obtained based on the measured temperature and the oxygen concentration;
An oxygen concentration measurement method comprising: Irradiating an oxygen quenching substance provided on a target object with excitation light;
Measuring the brightness of the oxygen quenching substance using an optical fiber;
Measuring the temperature in the vicinity of the oxygen quenching substance;
Calculating the oxygen concentration from the brightness of the oxygen quenching substance using the relationship between the brightness of the oxygen quenching substance obtained based on the measured temperature and the oxygen concentration;
An oxygen concentration measurement method comprising: Irradiating an oxygen quenching substance provided at the tip of the optical fiber with excitation light;
A step of measuring the brightness of the region facing the oxygen-containing gas in the oxygen quenching substance using an optical fiber;
Measuring the brightness of a region facing oxygen at a first predetermined concentration of the oxygen quenching substance using an optical fiber;
Measuring the brightness of a region facing oxygen at a second predetermined concentration different from the first predetermined concentration of the oxygen quenching substance using an optical fiber;
Using the relationship between the luminance of the oxygen quenching substance obtained based on the luminance of the region facing the first predetermined concentration of oxygen and the luminance of the region facing the second predetermined concentration of oxygen, the oxygen concentration Calculating the oxygen concentration from the brightness of the transmitting region;
An oxygen concentration measurement method comprising: Irradiating an oxygen quenching substance provided on an object with excitation light;
A step of measuring the brightness of the region facing the oxygen-containing gas in the oxygen quenching substance using an optical fiber;
Measuring the brightness of a region facing oxygen at a first predetermined concentration of the oxygen quenching substance using an optical fiber;
Measuring the brightness of a region facing oxygen at a second predetermined concentration different from the first predetermined concentration of the oxygen quenching substance using an optical fiber;
Using the relationship between the luminance of the oxygen quenching substance obtained based on the luminance of the region facing the first predetermined concentration of oxygen and the luminance of the region facing the second predetermined concentration of oxygen, the oxygen concentration Calculating the oxygen concentration from the brightness of the transmitting region;
An oxygen concentration measurement method comprising:

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