JP3192325U - Optical hydrogen gas detection switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an optical hydrogen gas detection switch capable of improving the responsiveness and reliability of hydrogen gas detection. A hydrogen gas detection element 2 is composed of a substrate 21, a gas chromic metal thin film 22, and a catalyst metal thin film 23. The color of the gas chromic metal thin film 22 is identified, and the identified color is converted into a color electric signal and output to the hydrogen discrimination means 5. The hydrogen discrimination means 5 discriminates a hydrogen gas leak based on a change in a color electric signal. [Selection diagram] Fig. 1

Description

  The present invention relates to the monitoring and discrimination of hydrogen gas leaks. Optical hydrogen that optically discriminates (detects) hydrogen gas leaks using the coloring properties of gas chromic metal thin films that absorb and color hydrogen atoms. It relates to a gas detection switch.

In manufacturing plants for glass, steel, chemical substances, fuel cells, semiconductors, etc., hydrogen gas may be used in the manufacturing process of semiconductors, or hydrogen gas may be generated in the manufacturing process. Hydrogen gas has a risk of exploding in an oxygen atmosphere and needs to be handled with care, and it is necessary to monitor and detect hydrogen gas leakage.
Similarly, a fuel cell using hydrogen gas as a fuel, a fuel cell vehicle, and the like have a risk of explosion due to hydrogen gas.

As a technique for monitoring and discriminating hydrogen gas leakage, Patent Document 1 discloses a hydrogen gas detection sensor in which a pair of electrodes and a detection film are stacked on the surface of an insulating substrate, and a heater is provided on the back surface of the insulating substrate. Sensing film is a metal oxide which increases the catalyst to dissociate the Pronto (H ⁺⁾ and electrons (e) to adsorb the hydrogen gas, the conductivity at reaction Pronto (H ⁺⁾ and electrons (e) Is done.

JP 2006-162365 A

  However, in Patent Document 1, since the metal film is heated by a heater when detecting hydrogen gas, the metal film is deteriorated and the response and reliability of hydrogen gas detection are poor.

  The present invention is an optical system that can improve the responsiveness and reliability of hydrogen gas detection by optically detecting hydrogen gas leakage using the coloring properties of gas chromic metal thin films that occlude and color hydrogen atoms. To provide a hydrogen gas detection switch.

  According to a first aspect of the present invention, there is provided a substrate, a gas chromic metal thin film that is formed on the surface of the substrate, and absorbs and colors hydrogen atoms, and is supported on the surface of the gas chromic metal thin film, and adsorbs hydrogen gas. A hydrogen gas detecting element dissociating into hydrogen atoms, a color identifying means for identifying a color of the gas chromic metal thin film, converting the identified color into a color electric signal, and outputting the color electric signal; An optical hydrogen gas detection switch, comprising: a hydrogen discrimination unit that discriminates hydrogen gas leakage based on a change in an electrical signal.

  According to a second aspect of the present invention, the hydrogen determination unit includes a signal storage unit that stores a reference color electrical signal indicating a color of the gas chromic metal thin film in an air atmosphere, and the reference color electrical signal from the color electrical signal. A signal calculation unit that calculates a difference electric signal by subtracting, a determination signal setting unit that sets a determination electric signal indicating a hydrogen gas concentration, and the difference electric signal and the determination electric signal are compared. The optical hydrogen gas detection switch according to claim 1, further comprising: a water channel leakage determination unit that determines that hydrogen gas leakage is greater than or equal to an electrical signal.

  According to a third aspect of the present invention, the color identification means receives a light emitting element, a light projecting lens that irradiates the gas chromic metal thin film from the catalyst metal thin film with light emitted from the light emitting element, and receives visible light of three primary colors. A light receiving element that converts the light intensity of the visible light wavelengths of the three primary colors into the color electric signal and outputs the light, and a light receiving lens that collects light from the gaschromic metal thin film and introduces the light into the light receiving element. The optical hydrogen gas detection switch according to claim 1 or 2.

  According to a fourth aspect of the present invention, the substrate is a transparent substrate, and the light receiving lens condenses light transmitted through the transparent substrate from the gas chromic metal thin film. This is an optical hydrogen gas detection switch.

  According to a fifth aspect of the present invention, the color identification means includes a light-emitting side optical fiber element that transmits light emitted from the light-emitting element to the light projecting lens, and a light-receiving side that transmits light collected from the light-receiving lens to the light receiving element. An optical hydrogen gas detection switch according to claim 3 or 4, comprising an optical fiber element.

According to the first aspect of the present invention, the color identifying means identifies the color of the gas chromic metal thin film, converts the identified color into a color electric signal, and outputs it to the hydrogen identifying means. In the hydrogen gas non-leakage (air atmosphere) and the hydrogen gas leak (hydrogen gas atmosphere), the color of the gas chromic metal thin film is different, and the color electric signals output from the color identification means are also different. Therefore, by monitoring the change in the color electrical signal with the hydrogen discrimination means, it is possible to discriminate hydrogen gas leakage based on the change in the color electrical signal.
Thereby, according to Claim 1 which concerns on this invention, hydrogen gas non-leakage or hydrogen gas leak is optically detected only by identifying the color of a gas chromic metal thin film, without heating a hydrogen gas detection element. It is possible to suppress the deterioration of the hydrogen gas detection element and improve the response and reliability of hydrogen gas detection.
Note that “color” means color, light and shade, and “color” includes color, light and shade, and gloss.

According to claim 2 of the present invention, in addition to the effect of claim 1, hydrogen gas leakage can be determined by comparing the differential electric signal and the determination electric signal.
For the reference color electrical signal, a hydrogen gas detection element is placed at the hydrogen gas measurement point in the air atmosphere, the color of the gas clock metal thin film is identified by the color identification means, and the identification color in the air atmosphere is converted to the reference color electrical signal And can be stored in the signal storage unit. In the discrimination signal section, a discrimination electric signal can be set according to the hydrogen gas concentration.

  According to the third aspect of the present invention, in addition to the effects of the first and second aspects, the light receiving element has three primary colors that are reflected by the gas chromic metal thin film or three primary colors that are transmitted through the gas chromic metal thin film. Is received, and the light intensity of the visible light wavelengths of the three primary colors is converted into a color electric signal and output to the hydrogen discrimination means. Thereby, hydrogen gas leakage can be discriminate | determined based on the light intensity (color electrical signal) of the visible light wavelength which shows the color of a gas chromic metal thin film.

  According to the fourth aspect of the present invention, in addition to the effect of the third aspect, a hydrogen gas detection element is disposed between the light projecting lens and the light receiving lens, and the transparent substrate (substrate) is transmitted from the gaschromic metal thin film. Can be collected by the light receiving lens.

  According to the fifth aspect of the present invention, in addition to the effects of the third and fifth aspects, the light-emitting side optical fiber element and the light-receiving side fiber element include hydrogen gas together with the light projecting lens, the light receiving lens, and the hydrogen gas detecting element. The light emitting element, the light receiving element, and the hydrogen discrimination means can be arranged outside the hydrogen gas monitoring area. In the hydrogen gas monitoring area, there is a risk of explosion due to hydrogen gas leakage. By disposing and extending the light emitting side optical fiber element and the light receiving side optical fiber element in the hydrogen gas monitoring area, hydrogen gas leakage can be monitored and detected in a safe area away from the hydrogen gas monitoring area.

It is a figure which shows the optical hydrogen gas detection switch of 1st Embodiment, Comprising: (a) is a schematic block diagram, (b) is a perspective view of a hydrogen gas detection element (hydrogen gas non-leakage). It is a figure which shows the apparatus housing | casing etc. which comprise the optical hydrogen gas detection switch of 1st Embodiment, (a) is a right view, (b) is an AA arrow line view of Fig.2 (a), (C) is BB sectional drawing of Fig.2 (a), (d) is CC arrow directional view of FIG.2 (b). It is a figure which shows the optical hydrogen gas detection switch of 1st Embodiment, Comprising: (a) is a schematic block diagram, (b) is a perspective view of a hydrogen gas detection element (hydrogen gas leak). It is a schematic block diagram which shows the optical hydrogen gas detection switch of 2nd Embodiment. It is a schematic block diagram which shows the optical hydrogen gas detection switch of 3rd Embodiment. It is a figure which shows the apparatus housing | casing etc. which comprise the optical hydrogen gas detection switch of 3rd Embodiment, (a) is a right view, (b) is the DD arrow directional view of Fig.6 (a), (C) is EE sectional drawing of Fig.6 (a), (d) is the FF arrow line view of FIG.6 (b).

An optical hydrogen gas detection switch according to the present invention will be described with reference to FIGS.
In addition, the optical hydrogen gas detection switch of 1st thru | or 3rd embodiment is demonstrated as a specific form of an optical hydrogen gas detection switch.

<First Embodiment>
The optical hydrogen gas detection switch according to the first embodiment will be described with reference to FIGS.

  1 to 3, an optical hydrogen gas detection switch X1 (hereinafter referred to as “optical hydrogen gas detection switch X1”) of the first embodiment includes an apparatus housing 1, a hydrogen gas detection element 2, and a color identification means 3. , A hydrogen discrimination means 5 and an alarm means 6.

As shown in FIG. 2, the device housing 1 is formed in a rectangular box body by front and rear plates 11 and 12, left and right plates 13 and 14, a ceiling plate 15 and a bottom plate 16, and has an internal space K.
The apparatus housing 1 includes an opening window 17, a mounting table 18, and a net plate 19. The opening window 17 is formed in the right plate 14 and communicates with the internal space K and the outside of the apparatus housing 1. The mounting table 18 is disposed in the internal space K of the apparatus housing 1 and is fixed to the bottom body 15. The mesh plate 19 is disposed in the internal space K of the apparatus housing 1 and covers the opening window 17. The mesh plate 19 is fixed to the right plate 14 of the apparatus housing 1 so as to be removable.

  As shown in FIGS. 1 to 3, the hydrogen gas detection element 2 includes a substrate 21, a gas chromic metal thin film 22, and a catalyst metal thin film 23.

As shown in FIGS. 1 to 3, the substrate 21 is made of amorphous quartz glass (SiO ₂ ), a metal such as aluminum (Al) or iron (Fe), or a ceramic. As the substrate 21, for example, quartz glass is used as a transparent substrate.

As shown in FIG. 1 to FIG. 3, the gas chromic metal thin film 22 occludes hydrogen atoms (H ⁺ : pronto) and colors. The gas chromic metal film 22 is an oxide-based metal, which is molybdenum oxide (MoO _x ), tungsten oxide (WO _x ), tantalum oxide (TaO _x ), titanium oxide (TiO _x ), vanadium oxide (VO _x ). , Chromium oxide (CrO _x ), zirconia oxide (ZrO _x ), haonium oxide (HfO _x ) or yttrium oxide (YO _x ).
For example, a tungsten trioxide thin film (WO ₃ ) is used as the gaschromic metal thin film 22. When a tungsten trioxide thin film (WO ₃ ) occludes hydrogen atoms (H ⁺ ), it is colored (discolored) from light green (before occlusion of hydrogen atoms) to dark blue. The tungsten trioxide thin film is deposited (supported) on the surface of the substrate 21 by sputtering (for example, high frequency magnetron sputtering) of metallic tungsten in a reduced pressure oxidizing atmosphere of argon and oxygen.

As shown in FIGS. 1 to 3, the catalytic metal thin film 23 is supported (deposited) on the surface of the gas chromic metal thin film 22, adsorbs hydrogen gas (H ₂ : hydrogen molecules), and hydrogen atoms (H ⁺ : Dissociate into pronto).
The catalytic metal thin film is platinum (Pt), palladium (Pd), nickel (Ni), rhodium (Rh), iridium (Ir) or ruthenium (Ru).
The catalytic metal thin film 23 can be supported (deposited) by a high frequency sputtering method, a direct current sputtering method, a molecular beam epitaxy method, or a vacuum deposition method. For example, the gas chromic metal thin film 22 is formed as a transparent thin film having a film thickness of 30 nm to 50 nm. It adheres on the surface of (tungsten oxide thin film).
As the catalytic metal thin film 23, for example, a platinum thin film (Pt) is used, and supported (deposited) on the surface of the tungsten trioxide thin film (WO ₃ ) by the above sputtering methods.

The hydrogen gas detection element 2 includes molybdenum oxide (MoO _x ), tungsten oxide (WO _x ), tantalum oxide (TaO _x ), titanium oxide (TiO _x ), vanadium oxide (VO _x ), chromium oxide (CrO _x ), and oxide. Any one gas clock metal thin film 22 is selected from zirconia (ZrO _x ), haonium (HfO _x ) or yttrium oxide (YO _x ), and platinum (Pt), palladium (Pd), nickel (Ni), rhodium One arbitrary catalytic metal thin film 23 is selected from (Rh), iridium (Ir), or ruthenium (Ru), and the selected gas chromic metal thin film 22 and the catalytic metal thin film 23 are configured.

  As shown in FIG. 2, the hydrogen gas detection element 2 is disposed in the internal space K of the apparatus housing 1. The hydrogen gas detection element 2 has a substrate 21 mounted on the mounting table 18 and is fixed to the mounting table 18 so as to be removable. The hydrogen gas detection element 2 is arranged with a catalytic metal film 22 (platinum thin film) facing the ceiling plate 15 of the apparatus housing 1.

The color identification means 3 identifies (discriminates) the color (color) of the gas chromic metal thin film 22 of the hydrogen gas detection element 2, converts the identified color into a color electric signal f1, and outputs it. Note that “color” means color, light and shade, and “color” includes color, light and shade, and gloss.
As shown in FIG. 1, the color identification unit 3 includes a color identification sensor (color sensor) and includes a light emitting unit 31 and a light receiving unit 32.

  The light emitting unit 31 includes a light projecting lens 33, a light emitting element 34, and a light emitting side optical fiber element 37.

  The light projecting lens 33 irradiates the gas chromic metal thin film 22 (tungsten trioxide thin film) with the light emitted from the light emitting element 34 (light) from the catalytic metal thin film 23 (platinum thin film). As shown in FIGS. 1 and 2, the light projecting lens 33 is disposed in the internal space K of the apparatus housing 1. The light projection lens 33 is disposed on the rear plate 12 side of the apparatus housing 1. The light projecting lens 33 faces the catalytic metal thin film 23 (platinum thin film) of the hydrogen gas detection element 2 and is disposed on the ceiling plate 15 side of the apparatus housing 1 with a space from the catalytic metal thin film 23.

  The light emitting element 34 is, for example, a light emitting diode (LED) that emits white light (hereinafter referred to as “light emitting diode 34”). The light emitting diode 34 is electrically connected to the LED drive circuit 35. The LED driving unit 35 is electrically connected to the LED power source 36.

The light-emitting side optical fiber element 37 is a glass fiber or a polyfiber, and is used as an optical fiber cable, for example.
The light emitting side optical fiber element 37 optically connects the light emitting diode 34 and the light projecting lens 33, and transmits the light emission (light) of the light emitting diode 32 to the light projecting lens 33. The light projecting lens 33 irradiates the catalyst metal thin film 2 (platinum thin film) with light transmitted by the light-emitting side optical fiber element 37. The light-emitting side optical fiber element 37 is inserted in the ceiling plate 15 of the apparatus housing 1, arranged in the internal space K of the apparatus housing 1, and optically connected to the light projecting lens 33. The light-emitting side optical fiber element 37 is drawn out of the apparatus housing 1 and optically connected to the light emitting diode 34 outside the apparatus housing 1.

  The light receiving unit 32 includes a light receiving lens 38, a light receiving element 39, and a light receiving side fiber element 41.

  The light receiving lens 38 condenses the light from the gas chromink metal thin film 22 (tungsten trioxide thin film) and introduces it into the light receiving element 39. As shown in FIGS. 1 and 2, the light receiving lens 38 is disposed in the internal space K of the apparatus housing 1. The light receiving lens 38 is arranged in parallel with the light projecting lens 33 and is disposed on the front plate 11 side of the apparatus housing 1. The light receiving lens 38 faces the catalytic metal thin film 21 (platinum thin film) of the hydrogen gas detection element 2 and is disposed on the ceiling plate 15 side of the apparatus housing 1 with a space from the catalytic metal thin film 2.

The light receiving element 39 is constituted by, for example, a phototransistor (hereinafter referred to as “phototransistor 39”). The phototransistor 39 receives visible light of the three primary colors (red, green, and blue) in the visible light wavelength range (380 nm to 780 nm), and converts the light intensity of the visible light wavelengths of the three primary colors into the color electric signal f1 (photocurrent). Convert and output. The phototransistor 39 is electrically connected to the hydrogen discrimination means 5 through the signal amplifier 40. The signal amplifying unit 40 amplifies the color electric signal f1 and outputs it to the hydrogen discrimination means 5.
Thereby, the phototransistor 39 identifies the color of the gas chromic metal thin film 22 with the light intensity of the visible light wavelength, and converts the light intensity of the identified color into a color electric signal f1.

The light receiving side optical fiber element 41 is a glass fiber or a polyfiber, and is used as an optical fiber cable, for example.
The light receiving side optical fiber element 41 optically connects the photodiode 39 and the light receiving lens 38, and transmits light collected by the light receiving lens 38 to the photodiode 39. The light-receiving-side optical fiber element 41 is inserted in the ceiling plate 15 of the device housing 1, is disposed in the internal space K of the device housing 1, and is optically connected to the light-receiving lens 38. The light-receiving side optical fiber element 41 is pulled out of the apparatus housing 1 and optically connected to the phototransistor 39 outside the apparatus housing 1.

  In the color identification means 3, the light projecting lens 38 and the light receiving lens 38 are accommodated in an apparatus unit container 45 as shown in FIG. The unit container 45 is disposed in the internal space K of the apparatus housing 11 and faces the lenses 33 to 38 against the catalytic metal thin film 23 (platinum thin film).

The hydrogen determination means 5 receives the color electric signal f1 and determines hydrogen leakage based on the change of the color electric signal f1.
As shown in FIG. 1, the hydrogen determination unit 5 includes a control unit 51, a signal storage unit 52, a signal calculation unit 53, a determination signal setting unit 54, a hydrogen leak determination unit 55, and an input unit 56.

The control unit 51 is electrically connected to the phototransistor 39 through the color signal amplification unit 40. The control unit 51 is electrically connected to the signal storage unit 53, the signal calculation unit 53, and the input unit 56.
The control unit 51 is electrically connected to the LED driving unit 35 and outputs a light emission electric signal fd to the LED driving unit 35.

  The signal storage unit 52 stores the reference color electrical signal f2 as data. The reference color electrical signal f2 is a color electrical signal indicating the color (light green) of the gas chromic metal thin film 22 (tungsten trioxide thin film) in an air atmosphere (hydrogen gas non-leakage).

  The signal calculation unit 53 calculates the absolute value (f3 = | f2-f1 |) of the difference electric signal f3 by subtracting the electric color signal f1 from the reference color electric signal f2. The signal calculation unit 53 is electrically connected to the hydrogen leak determination unit 55 and outputs a differential electric signal f3 to the hydrogen leak determination unit 55.

The determination signal setting unit 54 sets a determination electric signal fh indicating the hydrogen gas concentration. For example, the determination signal setting unit 55 includes a variable resistor 54 </ b> A and is electrically connected to the main power supply 57. In the discrimination signal setting unit 54, the discrimination electric signal fh (current) is changed by changing the resistance value of the variable resistor 54A.
The discrimination electric signal fh (current) is set according to the hydrogen gas concentration to be discriminated (detected) with the reference color electric signal f2 (current) being zero.
When increasing the hydrogen gas concentration to be determined, the resistance value of the variable resistance value 54A is decreased to increase the determination electric signal fh (current). Conversely, when the hydrogen gas concentration to be determined is decreased, the variable resistor The resistance value of 54A is increased to decrease the discrimination electric signal fh (current).
The determination signal setting unit 54 </ b> A is electrically connected to the hydrogen leak determination unit 55 and outputs a determination electric signal fh to the hydrogen leak determination unit 55.

The hydrogen leak discriminating unit 55 compares the differential electric signal f3 and the discriminating electric signal fh, and discriminates hydrogen gas leak when the differential electric signal f3 is equal to or greater than the discriminating electric signal fn.
The hydrogen leakage determination unit 55 is electrically connected to the alarm device 6 and outputs an alarm electric signal fk to the alarm device 6.

  The input unit 56 includes a reference color electrical signal setting switch 56 </ b> A and is electrically connected to the control unit 51. The input unit 56 outputs the acquired electrical signal f4 to the control unit 51 based on the operation of the setting switch 56A.

  As shown in FIG. 1, the alarm means 5 (alarm device) inputs an alarm electric signal fk from the hydrogen leakage saddle 55 and issues an alarm. The alarm device 5 is configured by a horn, a bell, an indicator light, or the like, and is electrically connected to the hydrogen leak determination unit 55.

<Monitoring and discrimination (detection) of hydrogen gas leakage>
Next, monitoring and discrimination (detection) of hydrogen gas (H ₂ ) leakage by the optical hydrogen gas detection switch X1 will be described with reference to FIGS.
For convenience of explanation, FIG. 1 shows an air atmosphere in which hydrogen gas (H ₂ ) does not leak into the gas monitoring region Y (hereinafter referred to as “hydrogen gas non-leakage”), and FIG. This is a hydrogen gas atmosphere in which hydrogen gas (H ₂ ) leaks (hereinafter referred to as “hydrogen gas leak”). The gas monitoring area Y is an area where there is a risk of explosion due to hydrogen gas leakage.

In FIG. 1, the optical hydrogen gas detection switch X1 arranges the apparatus housing 11 in a hydrogen gas monitoring region Y such as a process or facility using hydrogen gas (H ₂ ) in a manufacturing factory, for example.
Thereby, the hydrogen gas detecting element 2, the light projecting lens 33, and the light receiving lens 18 are not leaked with hydrogen gas and are exposed to the air atmosphere.

In the optical hydrogen gas detection switch X1, the light emitting diode 34, the phototransistor 39, the signal amplifying unit 40, the LED driving unit 35, the LED power source 36, the hydrogen discriminating means 5, the main power source 57, and the alarm device 6 are set outside the hydrogen gas monitoring region Y. In the non-monitoring area Z. The non-monitoring area Z is an area that is not affected by the hydrogen gas explosion, for example, and is a safe area away from the gas monitoring area Y.
At this time, the light projecting lens 33 is optically connected to the light emitting diode 34 by the light emitting side optical fiber element 37 extending to the hydrogen monitoring region Y and the non-monitoring region Z. The light receiving lens 38 is also optically connected to the light receiving element 39 by the light receiving side optical fiber element 41.

  A person who monitors hydrogen gas leakage (hereinafter referred to as a supervisor) turns on the main power source 57, and further changes (selects) the resistance value of the variable resistor 54A in the discrimination signal setting unit 54 to make the discrimination. The discrimination electric signal fn corresponding to the hydrogen gas concentration to be detected is set.

  Subsequently, the supervisor operates the setting switch 56 </ b> A of the input unit 56. The input unit 56 outputs the acquired electrical signal f4 to the control unit 51 based on the operation of the setting switch 56A.

In the hydrogen determination means 5, the control unit 51 outputs the light emission electrical signal fd to the LED drive unit 35 when the acquired electrical signal f <b> 4 is input. The LED driving unit 35 emits light from the light emitting diode 34.
Light emission (light) of the light emitting diode 34 is transmitted to the light projecting lens 33 by the light emitting side optical fiber element 37. The light projection lens 33 irradiates the catalyst metal thin film 23 (platinum thin film) of the hydrogen gas detection element 2 with the light emitted from the light emitting diode 34 (light).

In the hydrogen gas non-leakage (air atmosphere) of FIG. 1, the hydrogen gas detection element 2 is not exposed to the hydrogen gas (H ₂ ) atmosphere. As a result, the gaschromic metal thin film 22 is not colored, and the tungsten trioxide thin film is not colored (dark blue) but remains light green (before hydrogen atom occlusion).
In the hydrogen gas detection element 2, the gas chromic metal thin film 22 reflects (reflects) light from the catalyst metal thin film 23. The reflected light is collected by the light receiving lens 38 and transmitted to the phototransistor 39 by the light receiving side optical fiber element 41.

Subsequently, the phototransistor 39 receives visible light of the three primary colors, converts the light intensity of the visible light wavelengths of the three primary colors into a color electric signal f1, and outputs it to the signal amplification unit 40. The signal amplifying unit 40 amplifies the color electric signal f1 and outputs it to the hydrogen discrimination means 5 (control unit 51).
When the color electric signal f1 is input, the control unit 51 stores the reference electric signal f2 (data) in the signal storage unit 52.

Subsequently, when hydrogen gas is not leaked, when the color electric signal f1 is further input, the control unit 51 reads out the reference color electric signal f2 from the signal storage unit 52, and the signal calculation unit outputs the color electric signal f1 and the reference color electric signal f2. To 53.
When the color electric signals f1 and f2 are input, the signal calculation unit 53 calculates the absolute value (f3 = | f2−f1 |) of the differential electric signal f3 and outputs the differential electric signal f3 to the hydrogen leakage determination unit 55. Further, the determination signal setting unit 54 outputs the determination electric signal fn to the hydrogen leakage determination unit 55.

The hydrogen leakage determination unit 55 receives the differential electric signal f3 and the determination electric signal fn, and compares the difference electric signal f3 and the determination electric signal fn.
When the hydrogen gas is not leaked, the differential electrical signal f3 is less than the discrimination electrical signal fn (f3 <fn), so the hydrogen leak discrimination unit 55 discriminates that the hydrogen gas is not leaked and outputs the alarm electrical signal fk to the alarm device 6. do not do.

  When hydrogen gas is not leaked, the alarm device 6 does not input an alarm electric signal fk from the hydrogen leak determination unit 55, and therefore does not issue an alarm.

In the hydrogen gas leakage of FIG. 3, the hydrogen gas (H ₂ ) fills the gas monitoring region Y and flows into the internal space K of the apparatus housing 11 from the opening window 17 and the mesh plate 19 (see FIGS. 2 and 3). ).
In the apparatus housing 11, a hydrogen gas detecting element 2 is exposed to a hydrogen gas atmosphere, the catalytic metal film 23 by adsorbing hydrogen gas (H _2), hydrogen gas (H ₂₎ a hydrogen atom (H ^+: Dissociated into pront) and electrons. Hydrogen atoms are diffused from the catalytic metal thin film 23 to the gas chromic metal thin film 23. The gas chromic metal thin film 23 is colored by a reduction reaction (reduction action). For example, a tungsten trioxide thin film changes from chemical formula: WO ₃ (light green) to chemical formula: H _x WO by a reduction reaction (reducing action), and is colored deep blue [see FIG. 3B].
As shown in FIG. 3, the light emission (light) of the light emitting diode 34 is irradiated to the hydrogen gas detection element 2 from the light projecting lens 37, and is reflected by the gas chromic metal thin film 22 to the light receiving lens 38. The reflected light is collected by the light receiving lens 38 and transmitted (introduced) to the phototransistor 37 by the light emitting side optical fiber element 41.

  In the hydrogen gas leakage, as shown in FIG. 3, the phototransistor 39 receives visible light of the three primary colors transmitted to the light-emitting side optical fiber element 41, and converts the light intensity of the visible light wavelengths of the three primary colors into a color electric signal f1. To do. At this time, the color electrical signal f1 is different from the reference color electrical signal f2 (f1 ≠ f2), and has a relationship of, for example, f1> f2. The phototransistor 39 outputs the color electrical signal f1 to the signal amplification unit 40, and the signal amplification unit 40 amplifies the color electrical signal f1 and outputs it to the control unit 51.

  Subsequently, in the hydrogen determination unit 5, the control unit 51 reads the reference color electrical signal f 2 from the signal storage unit 52 and outputs the color electrical signal f 1 and the reference color electrical signal f 2 to the signal calculation unit 53.

When the color electric signals f1 and f2 are input, the signal calculation unit 53 calculates the absolute value of the differential electric signal f3. In hydrogen gas leakage, the relationship between the color electrical signal f1 and the reference color electrical signal f2 is satisfied, and the differential electrical signal f3 does not become zero.
The signal calculation unit 53 outputs the differential electric signal f3 to the hydrogen leakage determination unit 55.

In the hydrogen gas leakage, when the differential electrical signal f3 is input, the hydrogen leakage determination unit 55 compares the differential electrical signal f3 with the differential electrical signal fn.
The hydrogen leak discriminating unit 55 discriminates hydrogen gas leak when the differential electrical signal f3 is equal to or greater than the judgment electrical signal fn (f3 ≧ fn). At this time, the hydrogen gas concentration in the gas monitoring region Y is equal to or higher than the hydrogen gas concentration to be determined.
On the other hand, when the differential electrical signal f3 is less than the discrimination electrical signal fn (f3 <fn), the hydrogen leak discrimination unit 55 determines that hydrogen gas is not leaking. At this time, the hydrogen gas concentration in the gas monitoring region Y is less than the hydrogen gas concentration to be determined.
Subsequently, when it is determined that hydrogen gas leaks, the hydrogen leak determination unit 55 outputs an alarm electric signal fk to the alarm device 6.

  In the hydrogen gas leakage, the alarm device 6 issues an alarm when the alarm electric signal fk is input.

Second Embodiment
The optical hydrogen gas detection switch of the second embodiment will be described with reference to FIG.
In FIG. 4, the same reference numerals as those in FIGS. 1 and 2 denote the same members and the same configuration, and thus detailed description thereof will be omitted.

  In FIG. 4, the optical hydrogen gas detection switch X2 of the second embodiment (hereinafter referred to as “optical hydrogen gas detection switch X2”) has the same configuration as the optical hydrogen gas detection switch X1 of FIGS. The arrangement of the light receiving lens 38 is changed.

In FIG. 4, the light receiving lens 38 is disposed in the internal space K of the apparatus housing 1 so as to face the substrate 22 (transparent substrate). The light receiving lens 38 is optically connected to the phototransistor 39 by the light receiving side optical fiber element 41.
Thus, the light projecting lens 33 and the light receiving lens 38 are arranged with the hydrogen gas detecting element 2 therebetween, the light projecting lens 33 is opposed to the catalytic metal thin film 22 (platinum thin film), and the light receiving lens 38 is the substrate 22 (transparent substrate). ).

  In FIG. 4, the light emission (light) of the light emitting diode 34 is irradiated to the catalytic metal thin film 22 through the light projection lens 33, and passes through the gas chromic metal thin film 22 and the substrate 21 (transparent substrate). The light (transmitted light) transmitted through the substrate 21 is collected by the light receiving lens 38 and transmitted (introduced) to the phototransistor 39 by the light receiving side optical fiber element 41.

  In the optical hydrogen gas detection switch X2, monitoring and discrimination (detection) of hydrogen gas leakage is the same as described with reference to FIGS.

<Third Embodiment>
The optical hydrogen gas detection switch X3 of the third embodiment will be described with reference to FIGS.
5 and FIG. 6, the same reference numerals as those in FIG. 1 and FIG.

  5 and 6, the optical hydrogen gas detection switch X3 (hereinafter referred to as “optical hydrogen gas detection switch X3”) of the third embodiment is the same as the optical hydrogen gas detection switch X1 of FIGS. A configuration is provided, and the arrangement of the color discrimination means 3 and the hydrogen discrimination means 5 is changed.

As shown in FIG. 5, the color identification unit 3 includes a light projecting lens 33, a light receiving lens 38, a light emitting diode 34, and a phototransistor 39 without having the optical fiber elements 37 and 41 in FIG. 1. The light projecting lens 33 and the light emitting diode 34 constitute the light emitting unit 31, and the light receiving lens 38 and the phototransistor 39 constitute the light receiving unit 32.
The light emission (light) of the light emitting diode 34 is directly introduced into the light projecting lens 33, and the reflected light reflected by the gaschromic metal thin film 22 is directly introduced into the phototransistor 39 from the light receiving lens 38.

  The color identification unit 3, the signal amplification unit 40, the LED drive unit 36, the LED power source 37, the main power source 37, and the hydrogen determination unit 5 are accommodated in a unit container 65 as shown in FIGS. The unit container 65 is disposed in the internal space K of the apparatus housing 11. The light projecting lens 33 and the light receiving lens 38 are opposed to the catalytic metal thin film 23 (platinum thin film) of the hydrogen gas detection element 2 with an interval in the internal space K of the apparatus housing 11.

The optical hydrogen gas detection switch X3 arranges the device housing 11 in the gas monitoring region Z, and monitors and discriminates hydrogen gas leakage as described with reference to FIGS.
The optical hydrogen gas detection switch X3 is optimal for the gas monitoring region Y where the risk of hydrogen gas explosion is low, and includes the hydrogen gas detection element 2, the color identification hand 3, and the hydrogen discrimination means 5 all in the device casing 11. Therefore, the optical hydrogen gas detection switch X3 can be downsized. The alarm unit 6 is electrically connected to the hydrogen leakage determination unit 54 (hydrogen determination unit 5) through wiring (not shown) drawn from the inside of the apparatus housing 11 to the outside.

  The present invention is optimal for monitoring and detecting hydrogen gas leakage.

X1 Optical hydrogen gas detection switch 2 Hydrogen gas detection element 3 Color identification means 5 Hydrogen discrimination means 21 Substrate 22 Gaschromic metal thin film 23 Catalyst metal thin film

Claims (5)

A substrate, a gas chromic metal thin film formed on the surface of the substrate that absorbs and colors hydrogen atoms, and a catalytic metal thin film that is supported on the surface of the gas chromic metal film and that adsorbs hydrogen gas and dissociates into hydrogen atoms. A hydrogen gas sensing element comprising:
A color identifying means for identifying the color of the gaschromic metal thin film, converting the identified color into a color electric signal and outputting;
Hydrogen discrimination means for inputting the color electrical signal and discriminating hydrogen gas leakage based on a change in the color electrical signal;
An optical hydrogen gas detection switch comprising: The hydrogen discrimination means includes
A signal storage unit for storing a reference color electric signal indicating the color of the gaschromic metal thin film in an air atmosphere;
A signal calculation unit for calculating a difference electric signal by subtracting the reference color electronic signal from the color electric signal;
A discrimination signal setting unit for setting a discrimination electric signal indicating the hydrogen gas concentration;
A hydrogen leakage determination unit that compares the differential electrical signal and the determination electrical signal, and determines that hydrogen gas leaks when the differential electrical signal is greater than or equal to the determination electrical signal;
The optical hydrogen gas detection switch according to claim 1, comprising: The color identification means includes
A light emitting element;
A light projecting lens for irradiating the gas chromic metal thin film from the catalytic metal thin film with light emitted from the light emitting element;
A light receiving element that receives visible light of the three primary colors, converts the light intensity of the visible light wavelength of the three primary colors into the color electric signal, and
A light receiving lens that collects light from the gaschromic metal thin film and introduces it into the light receiving element;
The optical hydrogen gas detection switch according to claim 1, wherein the optical hydrogen gas detection switch is provided. The substrate is a transparent substrate,
The light receiving lens is
The optical hydrogen gas detection switch according to claim 3, wherein the light transmitted through the transparent substrate is collected from the gas chromic metal thin film. The color identification means includes
A light-emitting side optical fiber element that transmits light emitted from the light-emitting element to the light projecting lens;
A light-receiving-side fiber element that transmits the condensed light of the light-receiving lens to the light-receiving element;
The optical hydrogen gas detection switch according to claim 3, wherein the optical hydrogen gas detection switch is provided.

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