JP3844297B2 - Hydrogen detection device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a hydrogen amount detection device that detects a hydrogen amount using a hydrogen storage alloy.
[0002]
[Prior art]
For example, a hydrogen amount detection sensor disclosed in Japanese Patent Application Laid-Open No. 10-73530 is known as a technique that uses volume expansion due to the storage of hydrogen by a hydrogen storage alloy to measure the amount of hydrogen. This hydrogen amount detection sensor is formed by adhering granular hydrogen storage alloy particles in a dense layer to one surface of a plate material and attaching a strain cage to the opposite surface of the plate material. When the hydrogen amount detection sensor is disposed in a hydrogen atmosphere and hydrogen is stored in the hydrogen storage alloy particles and expanded, the plate material is bent and the strain gauge is deformed, and a strain amount corresponding to the deformation is output. Therefore, the hydrogen amount in the hydrogen atmosphere can be detected by comparing the hydrogen storage amount-volume expansion characteristic of the hydrogen storage alloy measured in advance with the strain amount measured by the strain gauge.
[0003]
[Problems to be solved by the invention]
In order to repeatedly measure the hydrogen amount with a certain accuracy using the hydrogen amount detection sensor, the hydrogen storage amount-volume expansion characteristic of the dense granular MH aggregate fixed to the plate member may be unchanged. It is a premise.
However, since the hydrogen storage alloy particles are hard, poor toughness and easily pulverized, as described above, the hydrogen storage alloy particles are fixed to the plate as a dense layer, and the amount of strain corresponding to the curvature of the plate Is detected as the amount of hydrogen in the hydrogen atmosphere, the particles of the hydrogen storage alloy generated by repeated storage and release of hydrogen cause wear, pulverization, and dropping of the particles of the hydrogen storage alloy. The measurement value of the hydrogen amount detection sensor may change. For this reason, when the conventional hydrogen amount detection sensor is used to repeatedly detect the hydrogen amount, the volume expansion characteristics of the whole aggregate of the granular hydrogen storage alloy decreases, the measurement accuracy and sensitivity of the hydrogen amount decrease, There is a problem that the measured value changes.
Accordingly, an object of the present invention is to provide a hydrogen amount detection device that can accurately detect the amount of hydrogen even if hydrogen storage / release is repeated.
[0004]
[Means for solving the problems]
The present invention has been proposed in order to solve the above-mentioned problems, and the invention according to claim 1 is a hydrogen amount detection device, wherein the granular hydrogen storage alloy is partially exposed from the surface of the stretchable holding layer. And a strain sensor that detects expansion and contraction of the holding layer due to volume expansion when the hydrogen storage alloy occludes hydrogen, and the strain sensor is embedded and installed in the holding layer . A hydrogen amount detection device is provided. The holding layer has elasticity and expands due to expansion of the hydrogen storage alloy particles due to hydrogen storage, and contracts due to the release of hydrogen, so that no mutual sliding occurs between the particles. The same applies when hydrogen is released. For this reason, even if hydrogen occlusion / release is repeated, wear, pulverization, and dropout of the hydrogen storage alloy particles do not occur, and the performance of the hydrogen amount detection device is maintained constant. Further, the elongation of the holding layer is the sum of the expansion of all the hydrogen storage alloy particles, and the strain sensor measures this expansion, so that the sensitivity as a hydrogen amount detection device is improved. In this case, if the granular hydrogen storage alloy is formed in one layer and the granular hydrogen storage alloy is dispersed, the sensitivity of the hydrogen amount detection device is further improved.
In addition, occlusion and discharge | release of hydrogen are made | formed from the surface exposed to the exterior of the particle | grains of a hydrogen storage alloy.
[0005]
According to a second aspect of the present invention , in the hydrogen amount detection device according to the first aspect of the invention , at least one surface of the holding layer is fixed to a plate-like base made of a material having higher rigidity than the holding layer. Then, the present invention provides a hydrogen amount detection device in which the holding layer expands and contracts in the plane direction of the strain sensor by storing and releasing hydrogen of the hydrogen storage alloy .
In this way, the expansion / contraction direction of the holding layer due to the expansion of the granular hydrogen storage alloy is specified in the direction along the joint surface between the holding layer and the base, so that the sensitivity of the hydrogen amount detection device is improved.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of a hydrogen amount detection apparatus according to the present invention will be described below with reference to the accompanying drawings.
(First embodiment)
FIG. 1 is a perspective view showing the structure of a first embodiment of a hydrogen amount detection apparatus according to the present invention, and FIG. 2 is a longitudinal sectional view of FIG. The hydrogen amount detection apparatus 1 includes a single hydrogen detection layer 2 in which hydrogen storage alloy particles 2a that expand and absorb hydrogen and contract by releasing hydrogen, and expansion of the hydrogen storage alloy particles 2a. The data conversion layer 3 is configured to convert the quantity into quantity data. The data conversion layer 3 includes a resin layer 3b fixed to the base 3a by lamination, and a resin embedded in the resin layer 3b. It is composed of an integrated strain gauge 3c. The hydrogen storage alloy particles 2a are formed on the resin layer 3b so that the resin layer 3b exposes the upper part of each particle 2a from the upper surface of the resin layer 3b and the adjacent particles 2a are separated by a resin. Uniformly distributed and held throughout the upper layer. The resin layer 3b is fixed to the base 3a by an adhesive or baking. The resin layer 3b is made of a resin, for example, a fluororesin, corresponding to the heat generation temperature of the hydrogen storage alloy particles 2a during the hydrogen storage and the heating temperature for releasing hydrogen, and the hydrogen storage alloy particles 2a. Has a stretch property that expands by volume expansion when hydrogen is occluded and contracts when hydrogen is released. The base 3a suppresses the bending of the resin layer 3b during the volume expansion of the hydrogen storage alloy particles 2a, so that the extending direction of the resin layer 3b is a direction along the plane direction of the hydrogen detection layer 2. It is made of a material having higher strength than the resin layer 3b with respect to bending and pulling.
[0008]
3A shows a state before the hydrogen amount detection of the hydrogen amount detection device 1, and FIG. 3B shows a state when the hydrogen amount detection device 1 detects the hydrogen amount. As shown in FIG. 3A, before the detection of the amount of hydrogen, hydrogen is not stored in the hydrogen storage alloy particles 2a, so that the volume of each particle 2a contracts and the volume of the resin layer 3b also contracts. It becomes a state.
[0009]
In this state, when a strain measuring device (not shown) is connected to the strain gauge 3c of the hydrogen amount detection device 1 and the hydrogen amount detection device 1 is placed in a hydrogen atmosphere, as shown in FIG. The individual hydrogen storage alloy particles 2a of the detection device 1 store hydrogen and expand, and the resin layer 3b extends in a direction along the joint surface between the base 3a and the resin layer 3b. The extending direction is the plane direction of the hydrogen detection layer 2 by the base 3a, in other words, the direction along the joint surface of the base 3a and the resin layer 3b. When elongation occurs in the resin layer 3b as the holding layer, strain corresponding to the elongation of the resin layer 3b is generated in the strain gauge 3c integrated with the resin, and the amount of strain is output to the strain measuring instrument. Therefore, the amount of hydrogen can be accurately estimated by comparing the amount of strain measured by the strain gauge 3c with the correlation property between the amount of strain and the amount of hydrogen of the strain gauge 3c measured in advance under the same pressure and temperature. . In addition, when the said hydrogen amount detection apparatus 1 is used repeatedly as a hydrogen amount detection apparatus, what is necessary is just to heat the hydrogen amount detection apparatus 1 and to discharge | release hydrogen from each particle | grain 2a of a hydrogen storage alloy.
[0010]
The hydrogen amount detection device 1 has a structure in which the hydrogen detection layer 2 of the hydrogen storage alloy is one layer, and the expansion and contraction direction of the resin layer 3b is the arrangement direction of the particles 2a of the hydrogen storage alloy, in other words, the base 3a and the resin layer. It is specified in the direction along the joint surface with 3b. For this reason, even if the hydrogen storage alloy particles 2a are repeatedly expanded and contracted to detect the amount of hydrogen, the hydrogen storage alloy particles 2a do not slide. Further, since the elongation of the resin layer 3b is the sum of the expansion of the entire hydrogen storage alloy particles 2a, the sensitivity of the strain gauge 3c for measuring this expansion is substantially improved.
[0011]
In the hydrogen amount detection device 1, the elongation direction of the resin layer 3b is specified by the rigidity of the base 3a in the direction along the joint surface between the base 3a and the resin layer 3b. As shown in FIG. 5, it is desirable to dispose the resin layer 3b on the hydrogen detection layer 2 side. Moreover, in this embodiment, although the strain gauge 3c was illustrated as said strain sensor, you may measure strain amount using the strain sensor using an optical fiber.
In this embodiment, the expansion and contraction direction of the resin layer 3b is regulated by the base 3a. However, the base 3a is abolished and the bending strain of the resin layer 3b due to the volume expansion of the hydrogen storage alloy particles 2a is distorted. You may measure with strain sensors, such as gauge 3c. Even in this case, the particles 2a of the hydrogen storage alloy are dispersed in the plane direction with respect to the resin layer 3b, and the resin exists between the particles 2a. Therefore, the particles 2a caused by sliding between the particles 2a. Wear, pulverization, and dropout are prevented, so that the amount of hydrogen can be detected repeatedly.
Further, in order to further improve the sensitivity of the hydrogen amount detection device 1, a restriction plate (not shown) for restricting the width of the resin layer 3b in the width direction may be provided on both sides of the hydrogen detection layer 2 and the resin layer 3b. Good.
[0012]
(Second Embodiment)
FIG. 4 shows a second embodiment of the hydrogen amount detection device according to the present invention, FIG. 4 (a) is a perspective view of the hydrogen amount detection device 11, and FIG. 4 (b) is a longitudinal sectional view of FIG. 4 (a). is there. In this embodiment, the base 13a is formed in a cylindrical shape with an open upper end, and the hydrogen storage alloy particles 2a are uniformly dispersed and held by the resin layer 13b inserted into the base 13a. ing. The resin layer 13b is a porous body for exposing the internal hydrogen storage alloy particles 2a to the external hydrogen atmosphere to store hydrogen, and by volume expansion when the hydrogen storage alloy particles 2a store hydrogen. It stretches and conversely contracts when hydrogen is released. As shown in FIG. 5, a base material 13d for holding the internal holes 13c is dispersed inside the resin layer 13b. The strain gauge 3c is affixed on the surface of the resin layer 13b.
[0013]
The base material 13d is not particularly limited as long as it is a corrosion-resistant material capable of holding the holes 13c. However, in order to expose the hydrogen storage alloy particles 2a to the outside, the base material 13d is composed of a ceramic porous material. It is desirable to do. Further, when the resin layer 13b is made of a thermosetting resin and is heated after foaming so that the shape of the holes 13c can be maintained, the substrate 13d can be eliminated.
[0014]
FIG. 6 (a) shows a state before the hydrogen amount detection (hydrogen release) of the hydrogen amount detection device 11, and FIG. 6 (b) shows a state during hydrogen occlusion (hydrogen measurement).
As shown in FIG. 6 (a), before the hydrogen amount is detected, the hydrogen storage alloy particles 2a are not exposed to hydrogen and do not store hydrogen, so that elongation occurs in the resin layer 13b as the holding layer. The strain gauge 3c does not sense strain. In this state, when a strain measuring device (not shown) is connected to the strain gauge 3c of the hydrogen amount detection device 11 and the hydrogen amount detection device 11 is placed in a hydrogen atmosphere, the individual hydrogen storage alloy particles 2a are shown in FIG. Since hydrogen is occluded through the holes 13c of the resin layer 13b shown, the volume expands. Since the lower end surface and the outer peripheral surface of the resin layer 13b are constrained by the cylindrical base 13a, the resin layer 13b protrudes in the opening direction of the base 13a serving as a refuge. For this reason, the strain gauge 3c affixed on the upper surface of the resin layer 13b senses the strain amount corresponding to the bulge amount, and the sensed strain amount is output to the strain measuring instrument. Therefore, also in this embodiment, if the measured strain amount is compared with the correlation characteristic between the strain amount-hydrogen amount measured in advance by the hydrogen amount detector 11 under the same pressure and temperature, the hydrogen amount can be accurately determined. Can be estimated.
In the repeated measurement of the hydrogen amount, resin exists between the hydrogen storage alloy particles 2a of the hydrogen amount detection device 11, and the particles 2a move together with the resin constituting the resin layer 13b. Even if the particles 2a of the storage alloy repeatedly expand and contract in order to measure the amount of hydrogen, sliding between the particles 2a of the storage alloy does not occur. For this reason, the amount of hydrogen can be measured repeatedly as in the case of the hydrogen amount detection apparatus 1 of the first embodiment. The expansion and contraction direction of the resin layer 13b is specified in the direction along the axial direction of the base 13a by the bottom surface and the inner surface of the base 13a, and the expansion amount of the entire hydrogen detection layer 2 due to the expansion of the hydrogen storage alloy particles 2a. Therefore, the sensitivity of the hydrogen amount detection device 11 is greatly improved.
[0015]
In the hydrogen amount detection device 11, since the extending direction of the resin layer 13b is specified, the strain gauge 3c may be arranged at the center of the resin layer 13b along the axis X of the base 13a. Further, a strain sensor using an optical fiber may be used instead of the strain gauge 3c.
[0016]
7 to 9 show a hydrogen storage (hydrogen tank) to which the hydrogen amount detection device 11 is attached, FIG. 7 is a perspective view of the hydrogen storage, FIG. 8 is a cross-sectional view of the hydrogen storage, and FIG. FIG.
The hydrogen storage 20 is filled with hydrogen storage alloy particles MT, and a heat transfer tube 21 for switching between hydrogen storage and hydrogen release is attached.
The hydrogen amount detection device is the hydrogen amount detection device 11 described in the second embodiment, and a heat insulating adhesive or the like is used so that the strain of the hydrogen storage 20 in the initial stage does not act on the inner wall 20a of the hydrogen storage 20. It is attached. The hydrogen amount detection device 11 is separated from the hydrogen storage alloy particles MT in the hydrogen storage 20 by a box-shaped partition wall 22 attached to the inner wall 20 a of the hydrogen amount detection device 11, and is formed in the box-shaped partition wall 22. The hydrogen storage 20 communicates with the communication portion 22a.
In this example, the hydrogen storage alloy particles 2a of the hydrogen amount detection device 11 are made of the same material as the hydrogen storage alloy MH in the hydrogen storage 20, and the volume of the partition wall 22 corresponds to the expansion of the resin layer 13b. Determined. Incidentally, in this embodiment, a hydrogen storage alloy such as LaNi ₅ is used so that the temperature becomes a thermal equilibrium temperature of 60 ° C. when heated for hydrogen release.
Further, in this embodiment, the temperature of the hydrogen storage alloy particles MT of the hydrogen storage 20 and the temperature of the hydrogen storage alloy particles 2a of the hydrogen detection device 11 are quickly made the same on the base 13a of the hydrogen detection device 11. A plurality of fins 13e are attached to the outer surface, and each fin 13e extends into the hydrogen storage 20 through the communication portion 22a.
[0017]
The hydrogen amount of the hydrogen storage 20 is detected by the hydrogen amount detection device 11 when the hydrogen storage 20 is filled with hydrogen. In this case, a low-temperature heat medium is circulated through the heat transfer tube 21. At this time, the pressure in the hydrogen storage 20 is maintained at the hydrogen gas supply pressure of the hydrogen gas supply system, that is, the hydrogen storage pressure of the particles MT of the hydrogen storage alloy in the hydrogen storage 20, and the temperature flows through the heat transfer tube 21. It is cooled to the temperature of the heat medium, that is, the hydrogen storage temperature in the hydrogen storage 20. Of course, the communication part 22a of the partition wall 22 keeps the partition wall 22 at the same temperature and pressure as in the hydrogen storage 20. When hydrogen gas is filled into the hydrogen storage 20 from the hydrogen gas inlet / outlet 20b, the hydrogen storage alloy particles MT in the hydrogen storage 20 expand by absorbing the hydrogen gas, and the hydrogen storage alloy of the hydrogen amount detection device 11 is expanded. The particles 2a also swell by absorbing hydrogen gas through the holes 13 (see FIG. 5) of the resin layer 13b.
The strain gauge 3c attached to the hydrogen amount detection device 11 outputs a strain amount corresponding to the hydrogen amount in the hydrogen storage 20 to a strain measuring device (not shown). Therefore, the relationship between the hydrogen storage amount of the hydrogen storage 20 and the expansion amount of the hydrogen storage alloy particles 2a of the hydrogen amount detection device 11 installed in the hydrogen storage 20, that is, the strain amount of the strain gauge 3c, is converted into data. If the strain amount actually measured is compared with this, the hydrogen storage amount of the hydrogen storage 20 can be accurately estimated. In this example, the hydrogen amount detection device 11 described in the second embodiment is described as the hydrogen amount detection device. However, the hydrogen amount detection device 1 described in the first embodiment is attached to the inner wall 20a of the hydrogen storage 20. You may make it stick through a heat insulating adhesive so that the distortion | strain of the hydrogen storage 20 of an initial stage may not act.
[0018]
【The invention's effect】
As is apparent from the above description, the present invention exhibits the following excellent effects.
(1) Since the wear, pulverization, and dropout of the hydrogen storage alloy can be prevented, it can be used repeatedly for the measurement of the amount of hydrogen. In addition, the amount of expansion of the resin layer is the sum of the expansion of the granular hydrogen storage alloy, and since the expansion is detected by the strain sensor, the amount of hydrogen can be detected with high sensitivity (claims 1 and 3). .
(2) Since the expansion / contraction direction of the holding layer due to the expansion of the granular hydrogen storage alloy is specified in the direction along the bonding surface between the holding layer and the base, the sensitivity of the hydrogen amount detection device is substantially improved (claims) Item 2).
[Brief description of the drawings]
FIG. 1 is a perspective view with a part broken away to show the structure of a first embodiment of a hydrogen amount detection apparatus according to the present invention.
FIG. 2 is a longitudinal sectional view of FIG. 1, showing the structure of the first embodiment of the hydrogen amount detection apparatus according to the present invention.
3A and 3B show changes in the state of the hydrogen amount detection device according to the first embodiment, FIG. 3A is a cross-sectional view showing a state before the hydrogen amount detection of the hydrogen amount detection device, and FIG. It is sectional drawing which shows the state at the time of the hydrogen amount detection of a detection apparatus.
4A and 4B show a hydrogen amount detection device according to a second embodiment, in which FIG. 4A is a perspective view of the hydrogen amount detection device, and FIG. 4B is a longitudinal sectional view of FIG.
FIG. 5 is an enlarged cross-sectional view of a main part of FIG. 4 (b).
6A and 6B show changes in the state of the hydrogen amount detection device of the second embodiment, FIG. 6A is a cross-sectional view showing a state before the hydrogen amount detection of the hydrogen amount detection device, and FIG. It is sectional drawing which shows the state of time.
FIG. 7 is a perspective view of a hydrogen storage to which a hydrogen amount detection device is attached.
FIG. 8 is a cross-sectional view of hydrogen storage.
9 is a detailed cross-sectional view of a part A in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hydrogen amount detection apparatus 2 Hydrogen detection layer 2a Hydrogen storage alloy particle 3 Data conversion layer 3a Base 3b Resin layer (holding layer)
3c Strain gauge (strain sensor)
11 Hydrogen amount detection device 13a Base 13b Resin layer (holding layer)
13c hole 13d base material 13e fin 20 hydrogen storage 21 heat transfer tube 22 partition 22a communication part MT hydrogen storage alloy particles

Claims (2)

A hydrogen amount detection device, in which a granular hydrogen storage alloy is dispersed and arranged so as to be partially exposed from the surface of a stretchable holding layer, and is caused by volume expansion when the hydrogen storage alloy stores hydrogen. A strain sensor for detecting expansion and contraction of the holding layer ;
A hydrogen amount detection apparatus, wherein the strain sensor is embedded in the holding layer . At least one surface of the holding layer is fixed to a plate-like base made of a material having a rigidity higher than that of the holding layer, and the holding in the planar direction of the strain sensor is performed by storing and releasing hydrogen of the hydrogen storage alloy. The hydrogen amount detection device according to claim 1, wherein the layer expands and contracts .

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