CN201222049Y - Frequency conversion type oxygen sensor - Google Patents

Abstract

The utility model discloses a novel non-porous variable frequency oxygen sensor combining a sensitive battery cell with an oxygen pump plate to convert measurement of oxygen concentration into measurement of time t, which comprises a sensitive battery cell, an oxygen plate and a glass sealing glaze, wherein the glass sealing glaze is a cylinder with through holes, the edge of one end of the glass sealing glaze is connected with the sensitive battery cell, the edge of the other end of the glass sealing glaze is connected with the oxygen pump plate, a closed air cavity is formed by the sensitive battery cell, the oxygen pump plate and the glass sealing glaze, the inner surface of the sensitive battery cell is uniformly distributed with internal electrodes of the sensitive battery cell, and the outer surface of the oxygen pump plate is distributed with external electrodes of the oxygen pump plate. Due to the novel measurement method and simple process of the novel non-porous variable frequency oxygen sensor, industrial large-scale production can be easily realized, and thereby the novel non-porous variable frequency oxygen sensor has wide applicability.

Description

Frequency conversion type oxygen sensor

Technical field

The utility model relates to a kind of sensor that is used for the measurement environment oxygen concentration, relates in particular to frequency conversion type oxygen sensor.

Background technology

The measurement of oxygen concentration and be controlled at various industrial fields important effect is all arranged, people utilize the YSZ solid electrolyte to have good oxide ion conduction characteristic and are used for making concentration difference voltage-type, boundary current oxygen sensors.Wherein the boundary current oxygen sensors is owing to the characteristics that have the measuring accuracy height, need not reference gas are widely used.The working mechanism of forming the boundary current oxygen sensors at present has aperture diffused, porous diffused and dense diffusion barrier to hinder stratotype etc.But these several sensors also all exist some shortcoming and defect, long-time use easily makes aperture stop up distortion as pinhole type boundary electric current lambda sensor, the porosity of porous type boundary electric current lambda sensor is restive, the sensor consistance is relatively poor, and use the hole gas penetration potential of porous also can change for a long time, dense diffusion barrier hinders stratotype also to exist the deficiency too responsive to temperature, and these all can cause the measuring accuracy of sensor to decline to a great extent; And the sensor all is based upon realizing the indirect measurement to oxygen concentration on the Fundamentals of Measurement of electric signal.

Summary of the invention

Technical problem to be solved in the utility model is the present situation at prior art, provides to propose a kind of measurement that responsive battery sheet and oxygen pump sheet can be combined oxygen concentration and be transformed into the novel atresia frequency conversion type oxygen sensor that time t is measured.This sensor has wide region detection, technology advantage simple and with low cost.

The utility model mainly is made of responsive battery sheet, oxygen pump sheet, glass capsulation glaze and circuit four parts.Wherein responsive battery sheet and oxygen pump sheet are Y ₂O ₃Stable ZrO ₂The solid electrolyte ceramic sheet adopts the screen printing mode preparation that inside and outside Pt electrode and lead-in wire thereof are arranged on its two sides.Be sealed to small confined air air cavity with high temp glass sealing glaze along the periphery of the potsherd of responsive battery, oxygen pump then.Apply the electric current of constant magnitude, direction alternation by steady current source oxygen supply pump sheet, realize that the inside and outside concentration difference voltage of responsive battery sheet is at E ₁To E ₂The alternate of scope, record responsive battery sheet by time measuring instrument inside and outside concentration difference voltage at E ₁To E ₂The time t of range realizes tested gas oxygen dividing potential drop P ₁Measurement.

The technical scheme that the utility model adopted is: frequency conversion type oxygen sensor, comprise responsive battery sheet, oxygen pump sheet and glass capsulation glaze, and wherein: the glass capsulation glaze is the cylindrical shell with through hole; The bead of glass capsulation glaze one end is connected with responsive battery sheet; The bead of the glass capsulation glaze other end connects aerobic pump sheet; Responsive battery sheet, oxygen pump sheet and glass capsulation glaze surround an airtight air chamber; The inside surface of responsive battery sheet is evenly equipped with electrode in the responsive battery sheet; The outside surface of responsive battery sheet is evenly equipped with responsive battery sheet external electrode; Electrode in the uniform aerobic pump of the oxygen pump plate inner surface sheet; The uniform aerobic pump of oxygen pump sheet outside surface sheet external electrode.

Also comprise for optimizing the technical measures that the technical program takes: in the responsive battery sheet in electrode and the oxygen pump sheet electrode through the lead parallel connection, free measuring instrument one end that also is connected, the time measuring instrument other end connects responsive battery sheet external electrode; Time measuring instrument one end also is connected with steady current source; The other end of steady current source connects oxygen pump sheet external electrode.

Electrode free measuring instrument one end that also is connected in the responsive battery sheet, the time measuring instrument other end connects responsive battery sheet external electrode; Electrode also is connected with steady current source in the oxygen pump sheet; Oxygen pump sheet is externally connected with the other end of electrode steady current source.

Responsive battery sheet is Y ₂O ₃Stable ZrO ₂The solid electrolyte ceramic sheet; The Y of responsive battery sheet ₂O ₃Molar content is 7% to 10%; The thickness of responsive battery sheet is 0.2mm to 1mm.

Responsive battery sheet external electrode material is metal Pt, and sintering temperature is 850 ℃ to 1250 ℃.

Oxygen pump sheet is Y ₂O ₃Stable ZrO ₂The solid electrolyte ceramic sheet; The Y of oxygen pump sheet ₂O ₃Molar content is 7% to 10%; The thickness of oxygen pump sheet is 0.2mm to 1mm.

Oxygen pump sheet inner electrode is metal Pt, and sintering temperature is 850 ℃ to 1250 ℃.

The treatment temperature of glass capsulation glaze is 750 ℃ to 1000 ℃.

The utility model current oxygen sensors has that 400 ℃ to 700 ℃ following working signals of high temperature are stable, can to detect the oxygen concentration scope be 0.1% to 99% advantage.In addition,, be easy to realize large-scale industrialization production, have extensive applicability because its measuring method novelty and technology are simple.

Description of drawings

Fig. 1 is the structural drawing of the utility model embodiment 1;

Fig. 2 is the utility model embodiment 1,2 partials pressure of oxygen-voltage-to-current cycle variation diagram;

Fig. 3 is the relation curve of the utility model embodiment 1,2 time t and tested partial pressure of oxygen;

Fig. 4 is the structural drawing of the utility model embodiment 2.

Embodiment

Embodiment describes in further detail the utility model below in conjunction with accompanying drawing.

Figure grade explanation: electrode 8, the interior electrode 9 of oxygen pump sheet, oxygen pump sheet external electrode 10, contact conductor 11 in responsive battery sheet 1, oxygen pump sheet 2, air chamber 3, glass capsulation glaze 4, steady current source 5, time measuring instrument 6, responsive battery sheet external electrode 7, the responsive battery sheet.

Fig. 1 is the structural drawing of the utility model embodiment 1; Fig. 2 is the utility model embodiment 1,2 partials pressure of oxygen-voltage-to-current cycle variation diagram; Fig. 3 is the relation curve of the utility model embodiment 1,2 time t and tested partial pressure of oxygen; Fig. 4 is the structural drawing of the utility model embodiment 2.

Embodiment 1: frequency conversion type oxygen sensor, comprise responsive battery sheet, oxygen pump sheet and glass capsulation glaze, and wherein: the glass capsulation glaze is the cylindrical shell with through hole; The bead of glass capsulation glaze one end is connected with responsive battery sheet; The bead of the glass capsulation glaze other end connects aerobic pump sheet; Responsive battery sheet, oxygen pump sheet and glass capsulation glaze surround an airtight air chamber; The inside surface of responsive battery sheet is evenly equipped with electrode in the responsive battery sheet; The outside surface of responsive battery sheet is evenly equipped with responsive battery sheet external electrode; Electrode in the uniform aerobic pump of the oxygen pump plate inner surface sheet; The uniform aerobic pump of oxygen pump sheet outside surface sheet external electrode.

In the responsive battery sheet in electrode and the oxygen pump sheet electrode through the lead parallel connection, free measuring instrument one end that also is connected, the time measuring instrument other end connects responsive battery sheet external electrode; Time measuring instrument one end also is connected with steady current source; The other end of steady current source connects oxygen pump sheet external electrode.

Responsive battery sheet is Y ₂O ₃Stable ZrO ₂The solid electrolyte ceramic sheet; The Y of responsive battery sheet ₂O ₃Molar content is 7% to 10%; The thickness of responsive battery sheet is 0.2mm to 1mm.

Responsive battery sheet external electrode material is metal Pt, and sintering temperature is 850 ℃ to 1250 ℃.

Oxygen pump sheet is Y ₂O ₃Stable ZrO ₂The solid electrolyte ceramic sheet; The Y of oxygen pump sheet ₂O ₃Molar content is 7% to 10%; The thickness of oxygen pump sheet is 0.2mm to 1mm.

Oxygen pump sheet inner electrode is metal Pt, and sintering temperature is 850 ℃ to 1250 ℃.

The treatment temperature of glass capsulation glaze is 750 ℃ to 1000 ℃.

Embodiment 2: frequency conversion type oxygen sensor, comprise responsive battery sheet, oxygen pump sheet and glass capsulation glaze, and wherein: the glass capsulation glaze is the cylindrical shell with through hole; The bead of glass capsulation glaze one end is connected with responsive battery sheet; The bead of the glass capsulation glaze other end connects aerobic pump sheet; Responsive battery sheet, oxygen pump sheet and glass capsulation glaze surround an airtight air chamber; The inside surface of responsive battery sheet is evenly equipped with electrode in the responsive battery sheet; The outside surface of responsive battery sheet is evenly equipped with responsive battery sheet external electrode; Electrode in the uniform aerobic pump of the oxygen pump plate inner surface sheet; The uniform aerobic pump of oxygen pump sheet outside surface sheet external electrode.

Electrode free measuring instrument one end that also is connected in the responsive battery sheet, the time measuring instrument other end connects responsive battery sheet external electrode; Electrode also is connected with steady current source in the oxygen pump sheet; The other end of steady current source connects oxygen pump sheet external electrode.

Responsive battery sheet is Y ₂O ₃Stable ZrO ₂The solid electrolyte ceramic sheet; The Y of responsive battery sheet ₂O ₃Molar content is 7% to 10%; The thickness of responsive battery sheet is 0.2mm to 1mm.

Responsive battery sheet external electrode material is metal Pt, and sintering temperature is 850 ℃ to 1250 ℃.

Oxygen pump sheet is Y ₂O ₃Stable ZrO ₂The solid electrolyte ceramic sheet; The Y of oxygen pump sheet ₂O ₃Molar content is 7% to 10%; The thickness of oxygen pump sheet is 0.2mm to 1mm.

Oxygen pump sheet inner electrode is metal Pt, and sintering temperature is 850 ℃ to 1250 ℃.

The treatment temperature of glass capsulation glaze is 750 ℃ to 1000 ℃.

Its concrete oxygen determination principle is: keep the working sensor temperature T, apply earlier and constant flow to the pump oxygen electric current I of electrode 9 directions in the oxygen pump sheet, impel in oxygen pump sheet electrode 9 to survey following electrochemical reaction takes place by oxygen pump sheet external electrode 10 by 5 pairs of oxygen pumps of steady current source sheet 2:

O ₂+4e ^-→2O ^2-

Oxygen in the air chamber 3 is become oxonium ion, and under electric field driven, drifts about by the 9 side direction oxygen pump sheet external electrodes of electrode in the oxygen pump sheet, 10 sides, and survey the following electrochemical reaction of generation at oxygen pump sheet external electrode 10 by oxygen pump sheet 2:

2O ^2-→O ₂+4e ^-

Oxonium ion is reduced into oxygen, and is discharged into the air chamber outside, the oxygen in the air chamber 3 is progressively pumped, reduce partial pressure of oxygen P in the air chamber 3 ₂, the difference of increase air chamber 3 inside and outside oxygen concentrations.According to Nernst equation the concentration difference voltage E of 8 at electrode in responsive battery sheet external electrode 7, the responsive battery sheet is constantly increased.When reaching predetermined voltage E ₂The time, upset pump oxygen direction of current under the condition that keeps constant magnitude, promptly-I, oxygen is advanced in the air chamber 3 from extraneous pump, increase partial pressure of oxygen P in the air chamber 3 ₂, the difference of dwindling the inside and outside oxygen concentrations of air chamber 3 constantly reduces the concentration difference voltage E of 8 at electrode in responsive battery sheet external electrode 7, the responsive battery sheet.When reducing to predetermined voltage E ₁The time, with electric current upset once more under the condition that keeps constant magnitude, so go round and begin again again, wherein t is that concentration difference voltage is at E ₁To E ₂The time that range is required can record by time measuring instrument 6, during test with voltage E ₁Be made as and open timing threshold value, E ₂For closing the timing threshold value.Partial pressure of oxygen P in the air chamber 3 like this ₂, responsive battery sheet 1 inside and outside concentration difference voltage E, the oxygen pump sheet 2 pump oxygen electric current I one-period that will form as shown in Figure 2 is the cycle variation of t.And between these several parameters and the outer tested gas oxygen dividing potential drop P of air chamber 3 ₁Should exist certain mathematical relation, it specifically derives as follows:

Supposing that in time t oxygen supply pump sheet 2 applies constant flows to the pump oxygen electric current I of electrode 9 directions in the oxygen pump sheet by oxygen pump sheet external electrode 10, has outwards pumped n mole oxygen in the chamber, makes partial pressure of oxygen in the air chamber 3 by P ₂Become P ₂ ^/, the concentration difference voltage of 8 at electrode is by E in the responsive battery sheet external electrode 7, responsive battery sheet ₁Become E ₂According to faraday's electric charge law of conservation, can get:

It=4nF ... formula 1

Wherein, F is a Faraday constant.Suppose that oxygen is ideal gas in the air chamber 3, volume is V, then:

$(P_2-{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_2^{/})V=\mathrm{<figure-callout\; id="2"\; label="nRT\; Formula"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">nRT</figure-callout>}$ Formula 2

Wherein, R is a gas law constant.Can get by formula 1, formula 2:

$P_2-{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_2^{/}=\frac{\mathrm{<figure-callout\; id="4"\; label="ItRT"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">ItRT</figure-callout>}}{4\mathrm{<figure-callout\; id="3"\; label="FV\; Formula"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">FV</figure-callout>}}$ Formula 3

According to Nernst equation, by pump oxygen process initial state, the partial pressure of oxygen P in the air chamber 3 wherein ₂, the concentration difference voltage E of 8 at electrode in the responsive battery sheet external electrode 7, responsive battery sheet ₁And, state finally, wherein the partial pressure of oxygen P in the air chamber 3 ₂ ^/, the concentration difference voltage E of 8 at electrode in the responsive battery sheet external electrode 7, responsive battery sheet ₂And tested gas oxygen dividing potential drop P outside the chamber ₁, can get:

${\mathrm{<figure-callout\; id="1"\; label="E"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">E</figure-callout>}}_1=-\frac{\mathrm{RT}}{4F}\ln \frac{P_2}{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}\&DoubleRightArrow;\frac{P_2}{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}=e^{-\frac{4{\mathrm{FE}}_1}{\mathrm{RT}}}$ Formula 4

${\mathrm{<figure-callout\; id="2"\; label="E"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">E</figure-callout>}}_2=-\frac{\mathrm{RT}}{4\mathrm{<figure-callout\; id="2"\; label="F\; ln\; P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">F</figure-callout>}}\ln \frac{P_{}^{}}{}\frac{{}_2^{/}}{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}\&DoubleRightArrow;\frac{{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_2^{/}}{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}=e^{-\frac{4{\mathrm{FE}}_2}{\mathrm{RT}}}$ Formula 5

Can get by formula 3, formula 4, formula 5:

$\frac{P_2-{\mathrm{<figure-callout\; id="2"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_2^{/}}{{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}=e^{-\frac{4{\mathrm{FE}}_1}{\mathrm{RT}}}-e^{-\frac{4{\mathrm{FE}}_2}{\mathrm{RT}}}=\frac{\mathrm{<figure-callout\; id="4"\; label="ItRT"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">ItRT</figure-callout>}}{4\mathrm{FV}{\mathrm{<figure-callout\; id="1"\; label="P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">P</figure-callout>}}_1}$ Formula 6

$\stackrel{\&CenterDot;}{\&CenterDot;\&CenterDot;}\frac{\mathrm{<figure-callout\; id="1"\; label="t\; P"\; filenames="Y20082008761000082.png"\; state="\{\{state\}\}">t</figure-callout>}}{P_{}}=\frac{4\mathrm{FV}}{\mathrm{IRT}}(e^{-\frac{4{\mathrm{FE}}_1}{\mathrm{RT}}}-e^{-\frac{4{\mathrm{FE}}_2}{\mathrm{RT}}})$ Formula 7

After sensor typing, F, R are constant, T, E1, E2, V, when I is known, can be found out time t and tested gas oxygen dividing potential drop P by formula 7 ₁Proportional.

For with oxygen by the process that pumps outside the chamber in the chamber, owing to keep the size of current unanimity of oxygen pump, the variation range E of concentration difference voltage ₁To E ₂Also identical, therefore, it is a pair of reversible process that pump advances with pumping, and this pump advances the time of process and the relation that tested gas oxygen dividing potential drop also should have formula 7.

The utility model frequency conversion type oxygen sensor needs special-purpose heater and is heated to 400 to 700 ℃ in real work.

Frequency conversion type oxygen sensor for this reason shown in Figure 3 under T=650 ℃ of operational temperature conditions, execute the electric current I=20 μ A of oxygen pump, tested gas oxygen concentration change scope is 0.1 to 99% o'clock, chooses different E ₁To E ₂The time t of scope and tested gas oxygen dividing potential drop P ₁Relation curve, t among the figure _OutAnd t _InRepresent respectively oxygen pump is gone out outside the air chamber 3, responsive battery sheet 1 internal and external electrode concentration potential is by E ₁Change to E ₂Time and oxygen pumped in the air chamber 3, responsive battery sheet 1 internal and external electrode concentration potential is by E ₂Change to E ₁Time, other are similar.

As can be seen from Figure 3:

1, at different E ₁To E ₂In the scope, time t and tested partial pressure of oxygen P ₁Every experimental data all present extraordinary linear dependence relation, highly meet with theoretical derivation formula 8;

2, at identical E ₁To E ₂In the scope, pump advances and pumps the time experimental data and show, differs very little between two kinds, itself and tested partial pressure of oxygen P ₁Linear relationship also almost consistent, therefore on Fig. 3, shown high superposed, can't distinguish.This also confirms the establishment that our above-mentioned theory is inferred: it is a pair of reversible process that pump advances with pumping.

Claims (4)

1, frequency conversion type oxygen sensor comprises responsive battery sheet (1), oxygen pump sheet (2) and glass capsulation glaze (4), and it is characterized in that: described glass capsulation glaze (4) is the cylindrical shell with through hole; The bead of described glass capsulation glaze (4) one ends is connected with described responsive battery sheet (1); The bead of described glass capsulation glaze (4) other end is connected with described oxygen pump sheet (2); Described responsive battery sheet (1), oxygen pump sheet (2) and glass capsulation glaze (4) surround an airtight air chamber (3); The inside surface of described responsive battery sheet (1) is evenly equipped with electrode (8) in the responsive battery sheet; The outside surface of described responsive battery sheet (1) is evenly equipped with responsive battery sheet external electrode (7); Electrode (9) in the uniform aerobic pump of described oxygen pump sheet (2) the inside surface sheet; Described oxygen pump sheet (2) outside surface uniform aerobic pump sheet external electrode (10).

2, frequency conversion type oxygen sensor according to claim 1, it is characterized in that: the interior electrode (9) of electrode (8) and oxygen pump sheet is through lead (11) parallel connection in the described responsive battery sheet, free measuring instrument (6) one ends that also are connected, time measuring instrument (6) other end connects described responsive battery sheet external electrode (7); Time measuring instrument (6) one ends also are connected with steady current source (5); The other end of steady current source (5) connects described oxygen pump sheet external electrode (10).

3, frequency conversion type oxygen sensor according to claim 1 is characterized in that: electrode (8) free measuring instrument (6) one ends that also are connected in the described responsive battery sheet, and time measuring instrument (6) other end connects described responsive battery sheet external electrode (7); Electrode (9) also is connected with steady current source (5) in the described oxygen pump sheet; The other end of steady current source (5) connects described oxygen pump sheet external electrode (10).

4, according to claim 2 or 3 described frequency conversion type oxygen sensors, it is characterized in that: described responsive battery sheet (1) is Y ₂O ₃Stable ZrO ₂The solid electrolyte ceramic sheet; The thickness of described responsive battery sheet (1) is 0.2mm to 1mm.

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