JPH0434356A - Hydrogen sensor - Google Patents

Abstract

PURPOSE:To obtain a hydrogen sensor capable of easily measuring hydrogen with high accuracy by utilizing a hydrogen ion conductor. CONSTITUTION:Electrodes 21, 22 are provided to one surface of a hydrogen ion conductor 1 and, in a rate limiting means 4, a porous layer 42 is provided to the electrode 21 through an inorg. layer 41 so as not to directly cover the electrode with the vitreous substance of the porous layer 42 and an airtight layer 43 is provided to the side surface thereof. Voltage is applied across both electrodes 21, 22 from a power supply 5 and a current is measured by a current measuring means 6. A hater 8 is provided to the other surface of the hydrogen ion conductor 1 through an insulating layer 7 and heated at the time of measurement by a power supply 9 and the conductivity of a hydrogen ion is enhanced. Hydrogen H2 of the outside is limited in its rate by the rate limiting means 4 and the current value I to applied voltage V increases by the concn. of H2 and there is constant relation between the hydrogen concn. at constant voltage Vc and the limit current value I1 at that time and hydrogen can be measured from said current value I1.

Description

DETAILED DESCRIPTION OF THE INVENTION [Second Industrial Fields of Application] This invention relates to a hydrogen sensor using a hydrogen ion conductor.

:Prior art] There are various types of hydrogen sensors, such as a catalytic combustion type, a thermal conductivity type, and a cascro type.

1 Problem to be solved by this invention I The catalytic combustion type and the thermal conductivity type do not have good selectivity for hydrogen, and the cascro type is unsuitable for online measurement, has poor operability, and is large and expensive. Ta.

In view of the above points, an object of the present invention is to provide a hydrogen sensor that can easily measure hydrogen with high precision using a hydrogen ion conductor. In this method, a hydrogen ion conductor is provided with a pair of electrodes, a rate controlling means is provided on one of the pair of electrodes, and when a voltage is applied between both electrodes, the concentration of hydrogen is measured from the value of the current flowing between the electrodes. This is a hydrogen sensor made with

: Solid line example] FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention.

In the figure, 1 is a hydrogen ion conductor, Na20-Ca
PH of O-3iO2, Li20-La2O35iOz, etc.
It is composed of responsive glass and other materials. A pair of electrodes 21 and 22 are provided on one side of the hydrogen ion conductor 1, and one electrode 21 is provided with hydrogen rate controlling means 4 such as a porous layer made of inorganic powder and glass. In this example, as the rate controlling means 4, a porous layer 42 is provided on the electrode 21 via an inorganic layer 41, and the vitreous material of the porous layer 42 is t
What is shown is that the pole 21 is not directly covered, and an airtight layer 43 is further provided on the side surface.

Then, a voltage is applied between the picture electrodes 21 and 22 by the power supply 5, and the current value flowing between the two electrodes is measured by the current measuring means 6. Further, a heater 8 is provided on the other side of the hydrogen ion conductor 1 via an insulating layer 7, and a current is supplied to this heater 8 from a power source 9 to heat it.

When measuring, a current is applied to the heater 8 from a power source 9 to heat it and increase the conductivity of hydrogen ions.

Hydrogen H2 in the outside air is rate-controlled by the rate-limiting means 4 and transferred to the electrode 21.
The hydrogen ion conductor 1 is moved, and the following reaction occurs with the @ electrode 21 as the anode and the electrode 22 as the cathode.

Anode H2-2H” Eng2e Yin & 2H”+2e-H2 (02 absent) 2H”
2 e + 1 / 202 ``Hx 0 (Two reactions occur in the presence of 02) In other words, the hydrogen ion H''' produced by the reaction has an electric charge of f!
21 to the electrode 22, but if the pumping capacity of the hydrogen ion conductor 1 is sufficiently increased, the rate of external hydrogen H2 will be controlled by the rate limiting means 4, and it will exhibit a limiting current characteristic, as shown in FIG. The current value with respect to the applied voltage V shows a limiting current characteristic with a flat part, and increases with the concentration of H2, and the hydrogen concentration at a constant voltage Vc and the limiting current value I at that time (are shown in Fig. 7). There is a constant relationship, and hydrogen can be measured from this t flow value 11.

2 to 5 each show another embodiment of the present invention, and the same reference numerals as in FIG. 1 indicate the same components.

In FIG. 2, a perforated cap 40 is used as the rate controlling means.

In FIG. 3, electrodes 2 are placed on both sides of the substrate of the hydrogen ion conductor 1.
1.22, and one electrode 21 is provided with a rate-limiting means 4 similar to that shown in FIG.

In FIG. 4, electrodes 21.2 are placed on both sides of the hydrogen ion conductor 1.
2, a perforated cap 40 is provided on the electrode 21, and a heater 8 is provided on this perforated cap 40.

In FIG. 5, a porous substrate 3 is used as a rate controlling means, a first electrode 21 is provided on one side of the porous substrate 3, and this first electric current lFf! 21 is provided with a hydrogen ion conductor layer 10 such as a thin film, and further a second electrode 22 is provided on this hydrogen ion conductor layer 10.

In any case of these figures 2 to 5, both poles are 21
．． The hydrogen concentration is determined from the value of the current flowing between both electrodes when a voltage is applied between the two electrodes.

1. Effects of the Invention As stated above, the present invention measures hydrogen using a hydrogen ion conductor, so it is small, has little influence from atmospheric gases such as oxygen, and can measure hydrogen with high precision. can do something.

[Brief explanation of drawings]

1, 2, 3, 4, and 5 are configuration explanatory diagrams showing one embodiment of the present invention, and FIGS. 6 and 7 are characteristic diagrams. 1.10... Hydrogen ion conductor 521.22... Electrode, 3... Porous substrate, 4... Rate controlling means, 5...
Power supply, 6... Current measuring means, 7... Insulating layer, 8...
・Heater, 9...Power supply

Claims (1)

[Claims] 1. A hydrogen ion conductor that transmits hydrogen ions, a pair of electrodes provided on the hydrogen ion conductor, and a hydrogen rate-limiting means provided on one of the pair of electrodes. A humidity sensor that measures humidity from the value of the current flowing between the electrodes when a voltage is applied between the two electrodes. 2. Providing a first electrode on the porous substrate as a rate-determining means,
A hydrogen ion conductor layer is provided on this first electrode, a second electrode is provided on this hydrogen ion conductor layer, and hydrogen is measured from the value of the current flowing between the electrodes when a voltage is applied between both electrodes. . 3. The hydrogen sensor according to claim 1 or 2, wherein the hydrogen ion conductor or the rate controlling means is provided with a heater.