JP2004028756A - Hydrogen amount detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydrogen amount detector capable of accurately detecting a hydrogen amount even when the storage/release of hydrogen is repeated. <P>SOLUTION: A resin layer 3b as a layer retaining a particle 2 of a hydrogen storage alloy is provided. The particle 2 causes a part of a surface of the resin layer 3b to be exposed so as to store hydrogen or emit hydrogen to the outside. A distortion sensor (distortion gauge) is provided on the resin layer 3b so as to detect a volume expansion when the particle 2a of the hydrogen storage alloy stores hydrogen. Since the layer retaining the particle 2a of the hydrogen storage alloy is a single layer, and the resin layer 3b stretches as the expansion is caused when the particle 2a of the hydrogen storage alloy stores hydrogen, sliding between the particles 2a is prevented. The same applies to the particle 2a when the hydrogen is emitted. Therefore, even after repeating the storage/release, the particle 2a of the hydrogen storage alloy is prevented from abrasion, pulverization and omission, thereby keeping capacity of the hydrogen amount detector uniform. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a hydrogen amount detecting device that detects a hydrogen amount using a hydrogen storage alloy.
[0002]
[Prior art]
As a technique for measuring the amount of hydrogen by using the volume expansion caused by the hydrogen storage alloy storing hydrogen, for example, a hydrogen amount detection sensor disclosed in Japanese Patent Application Laid-Open No. 10-73530 is known. In this hydrogen amount detection sensor, granular hydrogen storage alloy particles are fixed as a dense layer to one surface of a plate, and a strain cage is attached to the opposite surface of the plate. When the hydrogen amount detection sensor is placed in a hydrogen atmosphere and hydrogen is absorbed into the particles of the hydrogen storage alloy 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 amount of hydrogen in the hydrogen atmosphere can be detected by comparing the previously measured hydrogen storage amount-volume expansion characteristic of the hydrogen storage alloy with the strain amount measured by the strain gauge.
[0003]
[Problems to be solved by the invention]
In order to repeatedly measure the amount of hydrogen with the hydrogen amount detection sensor 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 invariable. It is a premise.
However, since the particles of the hydrogen storage alloy are hard, poor in toughness, and easily pulverized, as described above, the particles of the hydrogen storage alloy are fixed to the plate as a dense layer, and the amount of strain corresponding to the curvature of the plate is determined. Is detected as the amount of hydrogen in the hydrogen atmosphere, the particles of the hydrogen storage alloy slide due to the repeated storage and release of hydrogen, causing wear, pulverization, and falling off of the particles of the hydrogen storage alloy. In some cases, a change occurs in the measurement value of the hydrogen amount detection sensor. For this reason, when repeatedly detecting the amount of hydrogen using a conventional hydrogen amount detection sensor, a decrease in the volume expansion characteristic of the entire aggregate of the granular hydrogen storage alloy, a decrease in the measurement accuracy and sensitivity of the hydrogen amount occur, There is a problem that the measured value changes.
Therefore, an object of the present invention is to provide a hydrogen amount detection device that can accurately detect the amount of hydrogen even if the storage and release of hydrogen are repeated.
[0004]
[Means for Solving the Problems]
The present invention has been proposed in order to solve the above-mentioned problem, and the invention according to claim 1 is a hydrogen amount detecting device, in which a granular hydrogen storage alloy is partially exposed from the surface of an elastic holding layer. The present invention provides a hydrogen amount detection device provided with a strain sensor that detects the expansion and contraction of the holding layer due to volume expansion when the hydrogen storage alloy absorbs hydrogen.
Since the holding layer has elasticity and expands due to the expansion of the hydrogen storage alloy particles due to hydrogen storage and contracts due to the release of hydrogen, mutual sliding does not occur between the particles. The same applies when hydrogen is released. For this reason, even if the storage and release of hydrogen are repeated, the particles of the hydrogen storage alloy do not wear, pulverize, or fall off, and the performance of the hydrogen amount detection device is kept constant. In addition, the elongation of the holding layer is the sum of the expansion of the entire particles of the hydrogen storage alloy, and the strain sensor measures the expansion, so that the sensitivity as a hydrogen amount detecting device is improved. In this case, if the granular hydrogen storage alloy is used as one layer and the granular hydrogen storage alloy is dispersed, the sensitivity of the hydrogen amount detection device is further improved.
The storage and release of hydrogen are performed from the surface exposed to the outside of the particles of the hydrogen storage alloy.
[0005]
According to a second aspect of the present invention, in the first aspect of the invention, at least one surface of the hydrogen amount detecting device is fixed to a plate-like base, and the strain sensor is disposed inside the holding layer. It is intended to provide a hydrogen amount detecting device.
With this configuration, since the direction of expansion and contraction of the holding layer due to expansion of the granular hydrogen storage alloy is specified in a direction along the joint surface between the holding layer and the base, the sensitivity of the hydrogen amount detection device is improved.
[0006]
According to a third aspect of the present invention, there is provided a hydrogen amount detecting device, wherein a cylindrical base having one open end face, and a telescopic structure in which a granular hydrogen storage alloy is dispersed and arranged inside the base. And a hole provided in the holding layer, for exposing the granular hydrogen storage alloy to the outside, the expansion and contraction of the storage layer due to volume expansion when the hydrogen storage alloy absorbs hydrogen. It is an object of the present invention to provide a hydrogen amount detecting device in which a strain sensor for detecting is provided on a surface of the holding layer and on an open end surface side of the base.
In this case, the direction of elongation of the holding layer is regulated by the base, so that the direction of elongation of the holding layer at the time of hydrogen occlusion of the particles of the hydrogen storage alloy (at the time of measuring the amount of hydrogen) and the time of hydrogen release are the axis of the base. It is corrected in the center line direction. As a result, at the time of detecting the amount of hydrogen, the retaining layer rises in the direction of the opening of the base, and this strain is detected by the strain sensor. Since the granular hydrogen storage alloy is dispersed in the retaining layer and sliding between the particles does not occur, abrasion, pulverization, and falling off of the particles due to the sliding are prevented. The same applies when hydrogen is released. Therefore, the performance of detecting the amount of hydrogen of the hydrogen amount detecting apparatus is kept constant even if the occlusion / release is repeated for detecting the amount of hydrogen.
In addition, when the amount of hydrogen is detected, the elongation generated in the holding layer is the sum of the expansion of the particles of the hydrogen storage alloy, so that the sensitivity of the hydrogen amount detecting device to the measurement of the amount of hydrogen is substantially improved.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of a hydrogen amount detecting device according to the present invention will be described with reference to the accompanying drawings.
(1st Embodiment)
FIG. 1 is a perspective view showing a structure of a first embodiment of a hydrogen amount detection device according to the present invention, and FIG. 2 is a longitudinal sectional view of FIG. The hydrogen amount detection device 1 includes a hydrogen detection layer 2 in which particles 2a of a hydrogen storage alloy that expands by absorbing hydrogen and releases and contracts hydrogen are arranged in a plane, and expansion of the hydrogen storage alloy particles 2a. The data conversion layer 3 includes a resin layer 3b fixed to the base 3a by lamination, and a resin layer embedded inside the resin layer 3b. It is composed of an integrated strain gauge 3c. The particles 2a of the hydrogen storage alloy are formed so that the upper portion of each particle 2a is exposed to the outside from the upper surface of the resin layer 3b by the resin layer 3b, and the adjacent particles 2a are separated by the resin. It is uniformly dispersed and maintained throughout the upper layer. The resin layer 3b is fixed to the base 3a by an adhesive or baking. In addition, the resin layer 3b is made of a resin, for example, a fluororesin corresponding to a heating temperature for absorbing hydrogen and a heating temperature for releasing hydrogen of the hydrogen storage alloy particles 2a. Has elasticity that expands due to volume expansion when hydrogen is absorbed and contracts when hydrogen is released. Then, the base 3a suppresses the curvature of the resin layer 3b when the hydrogen storage alloy particles 2a expand in volume, so that the extension 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 against bending and tension.
[0008]
FIG. 3A shows a state before the hydrogen amount detection device 1 detects the hydrogen amount, 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, since hydrogen is not stored in the particles 2a of the hydrogen storage alloy, the volume of each particle 2a shrinks, and the volume of the resin layer 3b also shrinks. State.
[0009]
In this state, when a strain gauge (not shown) is connected to the strain gauge 3c of the hydrogen amount detecting device 1 and the hydrogen amount detecting device 1 is arranged in a hydrogen atmosphere, the hydrogen amount is increased as shown in FIG. Each hydrogen storage alloy particle 2a of the detection device 1 absorbs hydrogen and expands by absorbing hydrogen, and the resin layer 3b extends in a direction along the joint surface between the base 3a and the resin layer 3b. The direction of extension is the plane direction of the hydrogen detection layer 2 by the base 3a, in other words, the direction along the joint surface between the base 3a and the resin layer 3b. When elongation occurs in the resin layer 3b as the holding layer, a 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 device. Therefore, when the amount of strain measured by the strain gauge 3c is compared with the correlation characteristic between the amount of strain and the amount of hydrogen of the strain gauge 3c measured under the same pressure and temperature in advance, the amount of hydrogen can be accurately estimated. . When the hydrogen amount detecting device 1 is used repeatedly as a hydrogen amount detecting device, the hydrogen amount detecting device 1 may be heated to release hydrogen from each particle 2a of the hydrogen storage alloy.
[0010]
Due to its structure, the hydrogen amount detection device 1 has a single hydrogen storage layer 2 of hydrogen storage alloy, and the direction of expansion and contraction 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 3b. 3b is specified in the direction along the joint surface. For this reason, even if the particles 2a of the hydrogen storage alloy are repeatedly expanded and contracted for detecting the amount of hydrogen, sliding does not occur between the particles 2a of the hydrogen storage alloy. Further, since the elongation of the resin layer 3b is the sum of the expansion of the whole hydrogen storage alloy particles 2a, the sensitivity of the strain gauge 3c for measuring the expansion is substantially improved.
[0011]
In the hydrogen amount detection device 1, the extension direction of the resin layer 3b is specified in the direction along the joint surface between the base 3a and the resin layer 3b by the rigidity of the base 3a. As shown in (1), it is desirable to dispose it on the hydrogen detection layer 2 side of the resin layer 3b. Further, in this embodiment, the strain gauge 3c is exemplified as the strain sensor, but the strain amount may be measured by using a strain sensor using an optical fiber.
In this embodiment, the direction of expansion and contraction of the resin layer 3b is restricted by the base 3a. However, the base 3a is abolished, and the bending strain of the resin layer 3b accompanying the volume expansion of the particles 2a of the hydrogen storage alloy is reduced. It may be measured by a strain sensor such as the gauge 3c. Even in such a case, the particles 2a of the hydrogen storage alloy are dispersed in the resin layer 3b along the plane direction and the resin exists between the particles 2a. Since the abrasion, pulverization, and falling off of the steel are prevented, the amount of hydrogen can be repeatedly detected.
Further, in order to further improve the sensitivity of the hydrogen amount detection device 1, regulating plates (not shown) may be provided on both sides of the hydrogen detecting layer 2 and the resin layer 3b to restrict the resin layer 3b from extending in the width direction. Good.
[0012]
(2nd 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 having an open upper end, and the particles 2a of the hydrogen storage alloy 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 absorbing the hydrogen by exposing the internal hydrogen storage alloy particles 2a to an external hydrogen atmosphere, and by the volume expansion when the hydrogen storage alloy particles 2a occlude hydrogen. It has an elasticity that expands and conversely contracts when hydrogen is released. As shown in FIG. 5, a base material 13d for holding the internal holes 13c is dispersed in the resin layer 13b. The strain gauge 3c is attached to the surface of the resin layer 13b.
[0013]
The material of 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, a ceramic porous material is used. It is desirable to do. When the resin layer 13b is made of a thermosetting resin, and after foaming, the shape of the holes 13c can be maintained by heating, the base material 13d can be eliminated.
[0014]
FIG. 6A shows a state before the hydrogen amount detection device 11 detects the hydrogen amount (hydrogen release), and FIG. 6B shows a state at the time of hydrogen storage (at the time of hydrogen measurement).
As shown in FIG. 6A, before the detection of the amount of hydrogen, the particles 2a of the hydrogen storage alloy are not exposed to hydrogen and do not store hydrogen, so that the resin layer 13b as a holding layer is elongated. Therefore, the strain gauge 3c does not sense the strain. In this state, when a strain gauge (not shown) is connected to the strain gauge 3c of the hydrogen content detection device 11 and the hydrogen content detection device 11 is placed in a hydrogen atmosphere, the individual particles 2a of the hydrogen storage alloy are shown in FIG. Since hydrogen is absorbed through the holes 13c of the resin layer 13b as 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 relief. For this reason, the strain gauge 3c attached to the upper surface of the resin layer 13b senses the strain amount corresponding to the amount of protrusion, and the sensed strain amount is output to the strain measuring device. Therefore, also in this embodiment, if the measured strain amount is compared with the correlation characteristic between the strain amount and the hydrogen amount measured by the hydrogen amount detection device 11 under the same pressure and temperature in advance, the hydrogen amount can be accurately determined. Can be estimated.
In the repeated measurement of the hydrogen amount, a resin is present between the particles 2a of the hydrogen storage alloy of the hydrogen amount detection device 11, and the particles 2a move integrally with the resin constituting the resin layer 13b. Even if the storage alloy particles 2a repeatedly expand and contract for measuring the amount of hydrogen, sliding of the hydrogen storage alloy particles 2a does not occur. For this reason, the hydrogen amount can be repeatedly measured in the same manner as in the hydrogen amount detection device 1 of the first embodiment. The expansion and contraction direction of the resin layer 13b is specified in the direction along the axis 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. , The sensitivity of the hydrogen amount detection device 11 is also greatly improved.
[0015]
In the hydrogen amount detecting device 11, since the direction of extension 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. It is a part detailed sectional view.
The hydrogen storage 20 is filled with particles MT of a hydrogen storage alloy, 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. It is attached. The hydrogen amount detecting 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 20a of the hydrogen amount detecting device 11, and is formed on the box-shaped partition wall 22. It communicates with the inside of the hydrogen storage 20 via the communication part 22a.
In this example, the particles 2a of the hydrogen storage alloy 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, when heated for hydrogen release in this embodiment, the hydrogen storage alloy such that the temperature becomes the thermal equilibrium temperature of 60 ° C., for example, using a LaNi _5.
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 storage device 11 are quickly made the same on the base 13a of the hydrogen storage device 11. Are mounted on the outer surface, and each fin 13e extends into the hydrogen storage 20 through the communication portion 22a.
[0017]
The detection of the amount of hydrogen in the hydrogen storage 20 by the hydrogen amount detection device 11 is performed 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 pressure of hydrogen storage of the hydrogen storage alloy particles MT 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 inside of the partition 22 is maintained at the same temperature and the same pressure as the inside of the hydrogen storage 20 by the communicating portion 22a of the partition 22. When the inside of the hydrogen storage 20 is filled with hydrogen gas from the hydrogen gas inlet / outlet 20b, the particles MT of the hydrogen storage alloy 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. Particles 2a also expand 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 meter (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 storage alloy device of the hydrogen amount detection device 11 installed in the hydrogen storage 20, ie, the strain amount of the strain gauge 3c, is converted into data. Then, by comparing this with the actually measured strain amount, the hydrogen storage amount of the hydrogen storage 20 can be accurately estimated. In this example, the hydrogen amount detecting device 11 described in the second embodiment has been described as being attached as the hydrogen amount detecting device. However, the hydrogen amount detecting device 1 described in the first embodiment is attached to the inner wall 20a of the hydrogen storage 20. The hydrogen storage 20 in the initial stage may be bonded via a heat insulating adhesive so as not to act.
[0018]
【The invention's effect】
As is apparent from the above description, the present invention exerts the following excellent effects.
(1) Since the hydrogen storage alloy can be prevented from being worn, pulverized, and dropped, it can be repeatedly used for measuring the amount of hydrogen. The amount of expansion of the resin layer is the sum of the expansion of the granular hydrogen storage alloy, and the expansion can be detected by the strain sensor, so that the amount of hydrogen can be detected with high sensitivity (claims 1 and 3). .
(2) Since the direction of expansion and contraction of the holding layer due to expansion of the granular hydrogen storage alloy is specified in a direction along the joint surface between the holding layer and the base, the sensitivity of the hydrogen amount detection device is substantially improved (claim). Item 2).
[Brief description of the drawings]
FIG. 1 is a partially cutaway perspective view showing a structure of a first embodiment of a hydrogen amount detection device according to the present invention.
FIG. 2 is a vertical sectional view of FIG. 1 showing a structure of the first embodiment of the hydrogen amount detecting device according to the present invention.
3A and 3B show a change in the state of the hydrogen amount detection device of the first embodiment, FIG. 3A is a cross-sectional view showing a state before the hydrogen amount detection device detects the hydrogen amount, and FIG. It is sectional drawing which shows the state at the time of hydrogen amount detection of a detection apparatus.
4A and 4B show a hydrogen amount detecting device of a second embodiment, FIG. 4A is a perspective view of the hydrogen amount detecting device, and FIG. 4B is a longitudinal sectional view of FIG. 4A.
FIG. 5 is an enlarged sectional view of a main part of FIG. 4 (b).
6A and 6B show a change in the state of the hydrogen amount detection device according to the second embodiment, FIG. 6A is a sectional view showing a state before the hydrogen amount detection device detects the hydrogen amount, and FIG. It is sectional drawing which shows the state at the 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 the hydrogen storage.
FIG. 9 is a detailed sectional view of a portion A in FIG. 8;
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Hydrogen detection apparatus 2 Hydrogen detection layer 2a Hydrogen storage alloy particles 3 Data conversion layer 3a Base 3b Resin layer (holding layer)
3c strain gauge (strain sensor)
11 Hydrogen amount detector 13a Base 13b Resin layer (holding layer)
13c Hole 13d Base material 13e Fin 20 Hydrogen storage 21 Heat transfer tube 22 Partition wall 22a Communication part MT Hydrogen storage alloy particles

Claims (3)

A hydrogen amount detection device, wherein a granular hydrogen storage alloy is dispersed and disposed so as to be partially exposed from the surface of a stretchable holding layer, and the hydrogen storage alloy is caused by volume expansion when storing hydrogen. A hydrogen amount detecting device comprising a strain sensor for detecting expansion and contraction of the holding layer. The hydrogen amount detecting device according to claim 1, wherein at least one surface of the holding layer is fixed to a plate-like base, and the strain sensor is disposed inside the holding layer. A hydrogen amount detection device,
A cylindrical base with one end open,
An elastic holding layer accommodated inside the base and having the granular hydrogen storage alloy dispersed therein,
A hole provided in the holding layer, for exposing the granular hydrogen storage alloy to the outside, wherein the strain sensor detects expansion and contraction of the holding layer due to volume expansion when the hydrogen storage alloy absorbs hydrogen. A hydrogen amount detection device provided on the surface of the layer and on the open end surface side of the base.

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