JPH045561A - Gas concentration sensor - Google Patents

Abstract

PURPOSE:To obtain the sensor which is small in size and low in electric consumption by providing a pair of electrodes on one side of a solid electrolyte, providing a standard material exhibiting a prescribed oxygen partial pressure on one of the electrodes and measuring the electromotive force between the electrodes. CONSTITUTION:The electrodes 21, 22 are formed on one side of the solid electrolyte 1 on a substrate which allows the transmission of oxygen ions. The one electrode 22 is provided with the standard material 3 which is coated with a hermetic layer 4 consisting of glass, etc. This standard material 3 consists of a mixture composed of Cr/Cr2O3, Ni/NiO, Mo/MoO2, etc., which thermodynamically exhibit the prescribed oxygen partial pressure P2 by temp. An electric current is supplied at need from a power source 7 to a heater 6 to heat the solid electrolyte 1 and the electromotive force generated between the electrodes 21 and 22 is measured by a measuring means 8, by which the oxygen partial pressure P1 of the measuring atmosphere is known. The concn. of the gases including oxygen is thus measured. The need for a standard gas is eliminated in this way and the formation of the device to a smaller size and lower cost is possible.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a concentration battery type sensor that uses a solid electrolyte to measure the concentration of a gas such as oxygen.

[Prior Art] Conventionally, concentration battery type oxygen sensors have been used in the combustion control field and the atmosphere control management field.

[Problems to be Solved by the Invention] This type of oxygen sensor has problems such as its large size, which causes disturbance to the measurement target, and the need for a large amount of power for heating and the need for a reference gas. .

SUMMARY OF THE INVENTION In view of the above points, an object of the present invention is to provide a compact, low-power consumption battery-type dust concentration sensor that does not require a reference dust.

[Means for Solving the Problems] The present invention provides a pair of electrodes on one side of a solid electrolyte that transmits oxygen ions, and a predetermined amount of oxygen covered with an airtight layer on one side of the pair of electrodes. This is a dust concentration sensor in which a reference material indicating partial pressure is provided, and the electromotive force generated between the electrodes is measured by a measuring means.

[Example] Fig. 1 is an explanatory diagram showing the configuration of an embodiment of the present invention. 4 In Fig. 1, reference numeral 1 indicates an oxygen ion solution in which yttrium oxide Y 20 s or the like is dissolved in zirconium oxide Z r 02 or the like. A transparent substrate-like solid #electrolyte is formed on one side of this solid electrolyte with electrodes 21 and 22 made of Pt, Ag, etc., formed by vapor deposition, sputtering, etc.;
The reference material 3 is covered with an airtight layer 4 such as glass.

This reference material 3 is a Cr/Cr203-Ni/Ni0. Mo
/MoO□, etc.

A heater 6 is formed on the other side of the solid electrolyte 1 via an insulating layer 5, and a current is supplied from a power source 7 to heat the heater 6. Furthermore, the electromotive force generated at the electrodes 21 and 22 is measured by the measuring means 8. Although not shown, the temperature may be measured using a temperature sensor located close to the heater 6. Further, the insulating layer 5 is provided to prevent current to the heater 6 from flowing through the solid electrolyte 1 and causing measurement errors.

That is, current is supplied from the power source 7 to the heater 6 as needed to heat the solid electrolyte 1. At this time, if the oxygen partial pressure in the measurement atmosphere is P and the oxygen partial pressure due to the reference substance 3 is P2, then
The oxygen partial pressure P2 near the electrode 22 due to the reference material 3 becomes constant at a certain temperature T, and both partial pressures P1. Picture electrode 2 according to P2
The electromotive force E generated between 1.22 and 22 is given by the following equation.

E= (RT/4F)I n (P2.,'p,)(1
) where R is the gas constant and F is the Faraday constant.

By measuring this electromotive force E with the measuring means 8, the oxygen partial pressure P1 of the measurement atmosphere can be determined, and the concentration of scum including oxygen can be measured.

Note that the temperature T may be measured by another temperature sensor or a temperature sensor provided close to the solid electrolyte 1 (not shown).

In this way, 02 gas measurement is possible without the need for a reference gas.

Note that the entire sensor may be covered with a porous filter to enhance the dustproof effect.

1. Effects of the Invention] As described above, the present invention provides a concentration battery type in which a pair of electrodes is provided on one side of a solid electrolyte, and a reference material is covered with an airtight layer and provided on one electrode. With this dust concentration sensor, no special reference dust is required, making the device significantly smaller and cheaper. In addition, since necessary components can be formed on the other side of the solid electrolyte, further downsizing and lower power consumption can be achieved.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing an embodiment of the present invention. 1... Solid electrolyte, 21.22... Electrode, 3...
Reference material, 4... Airtight layer, 5... Insulating layer, 6...
Heater, 7...Power supply, 8...Measuring means Figure 1

Claims (1)

[Claims] 1. A solid electrolyte that transmits oxygen ions, a pair of electrodes provided on one side of this solid electrolyte, and an airtight layer provided on one side of this pair of electrodes. A gas concentration sensor comprising a reference substance that indicates a predetermined partial pressure of oxygen covered with a gas and a measuring means that measures an electromotive force generated between electrodes. 2. The gas concentration sensor according to claim 1, further comprising a heater or a temperature sensor provided on the other side of the solid electrolyte.