DE2914947A1 - DEVICE FOR GAS ANALYSIS WITH GALVANIC FIXED ELECTROLYTE CELLS - Google Patents

Description

VEB Junkaior Dessau r, _Q

45 Dossau 28

Aiiener Strasse 43

Device for gas analysis with galvanic solid electrolyte cells

Field of application of the invention

The invention relates to a device for gas analysis with galvanic solid electrolyte cells which are used for control, Control and regulation purposes primarily on industrial gases and can be used in air and which can be achieved using potentiometric, amperometric and coulometric Process as well as catalytic effects with each slight modification for different individual or several simultaneous continuous determinations mainly of oxygen, sulfur dioxide, nitrogen oxides and carbon dioxide as well as for the detection of unburned gases in addition to oxygen. The facility provides a Basic concept for various types of solid electrolyte gas sensors represent.

Known technical solutions

The development of the scientific field of high-temperature electrochemistry Using solid electrolyte cells has led to the discovery of numerous solid electrolytes and to the development of various Arrangements and processes with solid electrolyte cells, which are continuous over a wide temperature range or discontinuous selective determination of individual components of pure and impure gas mixtures suitable. These devices are characterized by the fact that they directly supply electrical signals that can easily be fed to electronic display and registration devices or automatic control devices. It is particularly advantageous to introduce probes with the measuring point in the probe head directly into the area to be examined Industrial gas flow, the best way to get the gas through

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allows a filter body to diffuse by itself to the measuring point, so that no gas sample is sucked in with the aid of a pump must become. Such probes require little maintenance and deliver signals in short times for automation purposes are cheap; by the geometric design of the filter measuring cell arrangement, depending on the requirements a spatial and temporal communication of the industrial gas flows often reach strongly fluctuating gas concentration values.

Probes for measuring oxygen in flue gases have already been introduced commercially. They contain galvanic cells with oxide ion-conducting solid electrolytes usually made of stabilized zirconium dioxide; either they are from the environment or kept at operating temperature by an electric furnace.

Around flammable gas components - such as methane, carbon monoxide or to detect hydrogen in addition to oxygen, it has already been proposed to use solid electrolytes that conduct oxide ions Measure voltage between an electrode made of Pt, Pd or Rh and an electrode made of Ag or Au. Due to significant Differences in the catalytic activity of these electrodes occur electrical signals, their size with the concentration of flammable gases increases.

It has also been proposed that one be separated from the measuring gas space except for a narrow passage (capillary, gap or pores) Space to separate the oxygen by means of a galvanic cell via an oxide ion-conducting solid electrolyte, being the time of the flow of a constant current or the number of necessary current pulses up to practically complete oxygen separation are proportional to the oxygen concentration in the measuring gas. With this coulometric Procedure you do not need a reference electrode.

The possibility of impregnating porous inert bodies with electrolyte substances and of building solid electrolyte cells has long been known to use. Such cells with carbonate electrolyte and silver electrodes are used for potentiometric Determination of oxygen and carbon dioxide suggested

^been · 030011/0535

'■ "29U947

More recently it has been shown that many gaseous anhydrides can be determined potentiometrically in oxygen-containing gases with cells that contain salts with oxide anions of the anhydrides as solid electrolytes. For example, that are measurable ppm by volume of potassium sulfate as Pestelektrolyt and electrodes with platinum at 820 ⁰ C the Nernst equation largely corresponding voltages of so-called concentration cells over a range of about 1 to 10,000 resulted. However, with sensors of this type there is also a dependency on the quotient of the oxygen partial pressures that are present in the electrode spaces. The gross electrochemical electrode reactions and the cell reactions that can take place in the gas sensors of particular interest are as follows:

-Sensor

² "

SO ^ 2O ₂ + 2 β "^ Ο ² " O ₂ CD ^ 0 ₂ (2)

SOp sensor

2-

SO ₂ + O ₂ + 2 β "^ SO ₄ ^" S0 ₂ (D + 0 ₂ (1) ^ S0 ₂ (2) + O ₂ (2) C0 "sensor

CO ₂ + 1 O ₂ + 2 e ~ ^ CO ₃ ² "C0 ₂ (D + 2-0 ₂ (D ^ CO ₂ C2) +

NO ₂ sensor

+ i O ₀ (2)

If the oxygen partial pressure in the measuring gas is the same as that in the reference gas, for example in the case of trace measurements in air, then the influence of this pressure on the cell voltage becomes apparent. However, if the oxygen partial pressure in the measuring gas fluctuates strongly, for example when measuring in flue gases, it must be taken into account, for which the combination of the signals from the SO ₂ , CO ₂ or NO ₂ sensor with the signal from an oxygen sensor has been proposed.

About the uncomfortable gas reference electrodes with a known content. To avoid SO ₂ , CO ₂ or NO ₂ , fixed reference electrodes made of a metal and the corresponding salt of this can be used

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29H947

Metal can be used. As long as there is no reducing gas, reference electrodes made of silver and silver sulfate are suitable, carbonate or nitrate in solid solution in the solid electrolyte material.

The previously proposed devices for gas analysis with solid electrolyte cells are very varied in terms of the type and shape of the solid electrolyte, the design of the electrodes, the use of reference systems, heating and Filter devices and the arrangement of these components. For every gas analysis method with solid electrolyte cells and Special constructions have been given for each type of solid electrolyte; on the other hand, there are no constructions of gas measuring probes, which can be used multifunctionally.

Many special components and various arrangements are unfavorable for industrial series production. the This makes probes expensive and cannot be used in small industrial plants to the extent that it is worth seeing is.

Many proposed devices serve their purpose immediately after their manufacture, but are in Their mechanical and electrochemical properties are not stable enough to withstand the harsh industrial conditions To withstand long-term use. Also the requirements of a simple, safe assembly in the industrial series production many of the facilities proposed so far do not match; in particular, they are simple secured electrical Feed lines to the measuring cell are often not guaranteed.

Finally, metallic components are often used, where it is better to use ceramic parts to avoid corrosion should be.

Object of the invention

The invention aims at a device which is easy to manufacture on an industrial scale and with slight variations individual components and using many components that are already commercially available as relatively cheaper and more reliable Sensor with a large area of application for different individual gases or side by side for several different gases.

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Technical problem of the invention

The invention is based on the object of a probe-shaped Specify device with different solid electrolyte cells from as many commercially available ceramic parts as possible, their Solid electrolyte cells different ion conductors as well as electrode types and arrangements for known potentiometric, potentiometric-electrocatalytic, amperometric marriage and coulometric methods contain and deviate without substantial Allow changes to the basic structural design to be incorporated into the probe arrangement in a simple, stable manner. the Probe design is intended for the determination of different gases individually or simultaneously over the entire temperature range be used in which the respective measuring principle and cell material can be used.

Features of the invention

The invention is based on a hollow body with ionic conductivity or from a part containing different ionic conductivity Hollow body, which is called the base body in the following. The base body carries one or more measuring electrodes on the outside separate measuring electrodes and contains inside a reference system or several different measuring electrodes opposing frames of reference. The cell arrangement according to the invention is now characterized in that the wire feed lines to the individual electrodes with the help of bushings through holes and grooves at one end of the base body and by a multiple capillary tube with a latch and with the help of bends in the wire leads or on Corrosion-resistant parts attached to wire feed lines are secured against the effects of tension and torsion on the electrodes are attached to the base body and that the base body with the electrodes and the connected lines to a Gas-tight guide tube coaxial with the help of a glass or a sintered mass with the wire leadthroughs closed is attached gas-tight and together with the guide tube, with or without an electric oven, a temperature sensor and test gas line into a porous ceramic tube that acts as a filter and has a closed or penetrated bottom

is plugged. 030011/0535

The leads from the measuring electrodes are through ceramic insulating tubes relocated to the .finding of the base body that abuts the guide tube. They are there through holes in the base body perpendicular to its axis in notches made on the outside along the base body or in externally thinned points in the Inside the main body tube and then led to the guide tube, the lines in each case before and after the bore are bent at an angle of about 90 °.

The multiple capillary tube has an end face a latch that goes into a groove in the face of the facing The end of the body engages and prevents axial torsion. The electrical wiring from indoor and Outer electrodes are individually through the capillaries of the multiple capillary tube piece relocated. On electrical lines of internal electrodes are located directly in front of the point of passage by a capillary bends or in some way fixed corrosion-resistant parts that allow pulling through prevent through the capillary. Located immediately behind the points where electrical lines pass through capillaries bends or in some way fixed corrosion-resistant parts that the exertion of pressure through pipes prevent on electrodes.

To ensure the gas-tight connection of the base body with the cell arrangement on the guide tube, these bodies and this tube should have little expansion coefficient differ from each other; they are ground to match each other or otherwise suitably deformed and with a Sealing compound, the expansion coefficient of which is best between that of the base body and that of the guide tube, connected.

Parts of the base body for the measurement of large to small oxygen partial pressures consist of an oxide ion-conducting Solid electrolytes primarily based on stabilized zirconium dioxide. Parts of the body exclusively for the holdings of high oxygen partial pressures mainly exist made of porous, electrically non-conductive ceramic bodies, in which the pores with oxide ion-conductive solid electrolytes with

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Bismuth oxide are impregnated as the main component. Parts of the Solid body for measuring the partial pressures of sulfur-containing, nitrogen-oxide-containing or carbon-containing gases mainly made of porous, electrically non-conductive ceramic bodies in which the pores are impregnated with salts, their anions with the gaseous oxide to be determined analytically or with the compound to be determined analytically Gaseous oxide formed by oxidation with the exchange of electrons with the electrode metal and with oxygen are able to enter into an electrode reaction from the hot gas.

The measuring electrodes consist of porous layers of alloyed or unalloyed platinum metals with or without the addition of catalytically active oxidizing substances and porous layers of silver, gold or their alloys. For contacting, structures made of wire, sheet metal or wire mesh, primarily made of the same noble metal, are attached to which electrical lines in the form of non-scaling wires, primarily made of Kanthal, are welded.

The reference electrodes inside the tubular body are constructed like the Keßelectrodes or from an electron-conducting oxidic layer with contacting metallisehen Formed and manufactured from a reference gas, primarily air or air with a certain content of SOp, NOp or COp, surrounded. The reference system for cells for measuring gaseous oxides on the inside of the ceramic body impregnated with pure salt but can also consist of a layer that is formed from the salt in question with the addition of a silver salt, a silver layer on top and a contacting metallic one Formations insist, In such a facility, the reference system against the risk of exposure is less oxygenated or reducing gases are constantly flushed with air.

The measuring gas space and the reference electrode space are via a capillary at the end of the base body free of electrical lines connected with each other. As a result of negative pressure in the let gas space or by one generated with suitable aids small overpressure in the reference electrode compartment flows continuously Reference or purging gas via the reference electrodes through the capillary into the measuring gas space.

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ORIGINAL

4P 29U947

In order to carry out amperometric or coulometric processes, the electrodes and the measuring gas are designed over a large area facing outer electrode is surrounded by a tubular hollow body on the side of the electrical supply lines is attached to the base body in a gastight manner using sealing compound and the base body on the other side except for a gas passage gap, the gas passage of which can be restricted by introducing a porous cement.

The electric furnace for heating the test electrolyte cells If the ambient temperature is inadequate, it consists of a ceramic tube with preferably 16 longitudinal bores in the tube v / and. The heating conductor is passed through 14 of these holes. 26O The remaining holes are opposite, take the required one Number of thermocouples and contain incisions and cross bores for the passage of measuring gas.

For setting different high temperatures at different Measuring electrodes are these measuring electrodes in the middle of different ovens or at points with a temperature gradient of a furnace with the desired temperatures and brought under control by appropriately mounted thermocouples.

The part of the probe, which acts as a filter, encloses the named parts of the probe Send ceramic tube has pores with widths up to about 30 / um, primarily from 5 to 10 / um. In the bottom of the unilaterally closed Ceramic filter tube is an opening that can be pushed through the reference gas outlet capillary introduced. The ceramic filter tube For protection, it is placed in a ceramic or scale-proof metal tube with gas guiding devices and gas passage openings and is thus directly in the room with the analysis gas or in an arrangement for taking cross-sectional samples built-in.

If the discharge of the gas flowing over the reference electrodes into the analysis gas space is not permitted, the base body is closed at the end without electrical lines by a sealant, the filter tube is not pierced at the bottom and through a notch in the multiple capillary tube a tube for

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BATH ORIGINAL

-K-

15th 29H947

Pressing gas into the reference electrode compartment. The space inside the ceramic filter tube around the measuring electrodes around is to the side of the outflowing reference gas and to the opposite side through parts made of ceramic or oxidic fiber material and largely sealed against dust »

The measuring electrodes are so from parts of the furnace or from Ceramic tubes are encased so that suspended particles that have penetrated the probe do not fall on the measuring electrode and only measuring gas Diffuse on the horizontal Y / eg to the measuring electrodes can.

The free space between the measuring electrodes and the ceramic filter tube is made up of loaen pieces from 0.5 to 2.0 mm thick Gas-tight sintered magnesium oxide or stabilized zirconium oxide completely or partially filled.

A multifunctional solid electrolyte gas sensor especially for Measurements on flue gases from combustion systems are made from a tube made of oxidic solid electrolyte, each with a measuring electrode on the outside made of platinum (I) and gold (II) as well as with an inside

I and II opposite reference electrode made of platinum (III) and a porous ceramic tube with potassium sulfate in the pores, outside with a measuring electrode made of platinum (IV) and inside with a reference electrode (V) made of potassium sulfate with 1 mass% Silver sulfate and a layer of silver on top. This combination of solid electrolyte cells is gas-tight A guide tube is attached, contains clean air inside and is surrounded by an electric oven and filter tube on the outside so that that flue gas cleaned of dust is sent to the measuring electrodes I,

II and IV can diffuse in. Electronic devices are for oxygen measurement with electrodes I and III, for detection unburned gas components with the electrodes I and II and for the measurement of sulfur dioxide and trioxide with the electrodes I, III, IV and V in the for the formation of the desired Signals connected in a suitable manner.

A mono- or multifunctional solid electrolyte gas sensor Especially for portable devices for measuring gas partial pressures in the free atmosphere, on oxygen systems, in

030.011 / 0535

Work rooms, mine shafts, etc. also largely exist miniaturized parts, primarily from a base body with an outer diameter of 2 to 3 mm, and is equipped with a micro-oven that controls the sensor with the help of a portable or by means of a cable connected power source at the operating temperature, as well as when the ambient air is unusable equipped as reference gas with a reference gas reservoir.

There are replaceable gas filters and at the entry points of the gas for the reference system and the test gas Devices for the connection of floating cone devices (rotameters) for permanent or temporary control of the Gas flow rate.

The inventive design of the base body with the secured Wire leads to the electrodes allow easy assembly under normal conditions. The connection to the Guide tube and the sealing of all openings on this Connection points are reached in one step at high temperature. The parts used and the specified structure offer significant advantages for a relatively simple series production. The directional conception is not only very variable Possible applications, but also contains important prerequisites for a long service life of the Sensors in industrial gases: use of corrosion-resistant ceramic parts, non-scaling lead wires that are welded to contact networks and lead out of the probe without interruption, Dust retention through filters with a small pore size and hot gas space limitation, against dust sedimentation in the filter space Protected storage of the measuring electrode, absorbent and adsorbent for contaminant vapors.

Embodiments
35O In the accompanying drawings show:

Fig. 1: Top view of a simple solid electrolyte cell

with attached multiple capillary tube section; 1 a: a plan view of the end of the multiple capillary tube piece a facing the solid electrolyte tube; Pig · 1 b: section through the multiple capillary tube piece;

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BATH ORIGINAL

-yC-

Fig. 2: Section through the simple

with attached multiple capillary tube piece and part of the guide tube;

Fig. 2a; Section through a cut adaptation of the solid electrolyte tube to the guide tube;

Figure 2b

up to 2 f: sections and views of various devices, moving wires through the xeramikcapillaries impede;

Fig. 3: Section through a bifunctional arrangement a solid electrolyte tube;

4: Section through a solid electrolyte cell with large electrodes, the hollow body enveloping the flow electrode and attached parts;

Fig. 5: Section through a trifunctional arrangement
on two solid electrolyte tubes;

Fig. G : Section through the head of a probe with a
simple fixed electrolyte cell without heating furnace;
7: Section through the head of a probe with a bifunctional arrangement on a solid electrolyte tube in a heating furnace with gas passage openings in the

Middle part;

8: Section through a tube furnace for probe heating;

8 a: a top view of an end face of the tube furnace before it is smeared with protective compound;

Fig. 9: Section through a simple solid electrolyte cell with recirculation of the reference gas in a heating furnace with gas passage openings in the iindteil;

9 a: Top view of the end of the multiple capillary tube facing the solid electrolyte tube

lateral openings for gas feed-through;

Fig. 10: Top view of a probe with connector and Section through protective tube and installation site;

Fig. 10 a: Top view of the inside of the probe.

The construction of a simple solid electrolyte cell with the solid electrolyte tube 1, the outer electrode 2, the inner electrode 10, the ceramic insulating tube 3 »the bore 6 in the

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BA D ORIGINA L

Notch 5 and with the using the multiple capillary tube piece 7 fixedly mounted electrode leads 4 and 11 show the top view of FIG. 1 and rotated by 90 ° insert into the guide tube 13 with the insulation tube 14 in section the Fig. 2. The safeguard against the effect of tension, pressure or torsion on the electrodes 2 and 10 through the wire leads 4 and 11 will be with the bends before and after the bore 6, with the three welded-on, non-scaling metal plates 8 and with the bolt 9 (see Fig. 1a, 1b and 2) achieved. Fig. 1 alao shows a mechanically stable component that is produced by a single annealing process is connected to the guide tube 13 in a gas-tight manner with the sealing compound 12. The stable fit of the solid electrolyte tube 1 in the guide tube 13 can be improved by a ground joint, e.g. as by 17 in Fig. 2a. Instead of the metal plates 8, for example, scale-resistant metal tubes 18 can also be pushed over and pressed on or welded on (Fig. 2b), double-drilled ceramic platelets interwoven (Fig. 2c), scalloped-out dented in the central part Metal plate 20 pressed on (Fig. 2d) or only rounded (Fig. 2e) or bends (Fig. 2f) are made in the wire leads. Only after the connection the solid electrolyte cell with the guide tube, after checking the cell function and, if necessary, the inner electrode For improvement measures, the capillary 15 with the sintered mass is attached to the open end of the solid electrolyte tube 16 set.

The solid electrolyte tube 1 consists of stabilized zirconium dioxide for measurements of large to small oxygen partial pressures. For measurements on solid electrolytes that cannot be processed into mechanically stable tubes on their own, a porous ceramic tube is made, for example, with a mixture of 80% by mass / © AIgO ^ and 20% by mass of SiO ₂ or from pure AIgO or MgO, attached to the guide tube and impregnated with one or different solid electrolyte material, ideally in the molten state. However, you can also use a gas-tight pipe made of sintered corundum with the necessary number of windows,

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BATH ORIGINAL

in which pure solid electrolyte bodies or porous ceramic bodies with solid electrolyte in the pores are used.

_{A mixture of a glass made from 8 parts BaC0o> 8 parts by weight SiOp and 1 part by weight Al 2} Oo and 5% by weight of finely mortar stabilized, for example, between CaO-stabilized zirconium dioxide as solid electrolyte 1 and Binterkorund as guide tube 13 has proven itself as sealing compound 12 Zirconia. To produce the pipe connection, the arrangement is ^{heated to 1375 °} C. in the area of the sealing brake. The coefficient of expansion can be varied by substituting a more or less large part of the BaCOo by CaCOo. The significantly greater thermal conductivity of the sintered compound compared to that of the zirconium dioxide must be taken into account by placing the maximum temperature of the furnace during the melting and cooling process in the area of the sintered corundum tube.

The electrodes of the simple solid electrolyte cell are made by applying a suspension of pure platinum particles of size ^ 10 / µm with the addition of soluble, pure alkali-free platinum compounds (up to 20% by mass of the metal content) in a viscous, well-drying, residue-free burning organic liquid, after which glowing should be the layer initially contains less than 5 mg / cm of platinum; by repeating the application, 8 to 20 mg / cm of platinum should be achieved. In order to improve the adhesive strength of the inner platinum layer, it is advantageous to add 1 to 5% by mass of a glass that is as alkali-free as possible to the platinum for this layer. The porous platinum layers are contacted with platinum wire nets to which kanthal wires are welded. By treating the cell for about 10 minutes between 800 and 1100 ^° C. with alternating current, the layers can have a current density between

2
0.2 and 1.5 A / cm in air before and repeatedly during long-term operation, thereby improving the response speed of the electrodes.

From Fig. 3 it can be seen that the construction is simple Way allows a second outer electrode 21 to be

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Offr

bring and a wire line 22 into the interior of the Guide tube a 13 with the iiehrfachkapillary tube 23 gas-tight lay au, electrode 21 is for example with gold, Electrode 2 and the common reference electrode 1ö made with platinum. On a solid electrolyte tube made of stabilized Zirconium dioxide can then be used to determine the oxygen partial pressure from the voltage between 2 and 10 prove the presence of flammable substances in addition to oxygen with the voltage between 2 and 21.

The examples described so far are intended for potentiometric determinations. For amperometrysehe and coulometric analysis method, it is appropriate to the To enlarge electrodes, as shown in Fig. 4 with the measuring electrode 24 and the counter electrode 25 shows. Around a limit current proportional to the gas concentration to be determined obtained or to determine the gas concentration of the repeated extensive separation of the gas from a gas sample To be able to, a volume is delimited by the hollow body 26 from the measuring gas. The tubular hollow body 26 is with the help of the sealing compound 12 gas-tight to a collar of the guide tube 13 connected via the annular gap 28, which can be restricted in its permeability with porous material, a continuous gas exchange takes place. Either the limit current flowing when a constant voltage is applied is measured or the limit current is determined over time and current Charge required for extensive separation of the gas after a period of complete concentration equalization is. Compared to potentiometric methods, there are the advantages that the gas concentration is carried out directly receives proportional signals and that it is possible to work with the counter electrode under measuring gas even without reference gas. The latter advantage is not used in the example shown in FIG. 4; instead, here is a Stabilization of the counter electrode by constant air purging or by standing under the separated oxygen achieved when sealing the solid electrolyte tube on one side or the other, disadvantageous compared to potentiometric Procedure is the need for calibration

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tion of any such measuring arrangement.

The number of measuring functions of a probe can be increased if, as shown, for example, in FIG However, the wire leads to one of the outer electrodes and to the air reference electrode are not visible in the section shown in Fig. 5. Solid electrolyte tube 29 can be a porous ceramic tube _{made from 80 IvIasse-yiJ Al 2} Ot and 20 mass SiO _{2 with K 2} SO The reference electrode in this tube then best consists of a layer 31 of K ₂ SO, with 1 IAase-, ί Ag ₃ SO ₄ and on top of it a layer of pure silver with a silver mesh 32 on the wire supply line 33 Kontaktiei-t is.

To prevent this reference electrode from being destroyed by reduction, it is important that the air flow through the Reference electrode in solid electrolyte tube 1 at the same time constantly floods the reference electrode in solid electrolyte tube 29.

The arrangement of the solid electrolyte cells attached to the guide tube FIGS. 6 and 6 show in a porous ceramic tube 34, which acts at the same time as a filter and carrier tube In Fig. 6 is a simple plague electrolyte cell without heating furnace in a support tube 35 with the locking disks 36, 37, 30 and 39, the jacket thermocouple 40 and the test gas line shown. The support tube 35 is porous and also has incisions on one side for the passage of gas. In Fig. 7 is a bifunctional arrangement corresponding to FIG. 3 iJti a tubular heating furnace 42 with cuts in the middle Area shown. Except for the jacket thermocouple 40 for which one measuring electrode 2 is for the second, outside the temperature maximum lying measuring electrode 21 a wide Sheathed thermocouple 43 is provided. The sheathed detectors are together with the test gas line 4I and the power supply lines of the heating furnace in the ceramic insulating tube 44 attached to the guide tube 13 with a ligature 45. The delimitation of the measuring gas chamber get the locking disks 37, 3β and 39, the asbestos embedded in the grooves of the heater

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BAD-QB1G1NAL

sz

threads 46 and 47, the support tubes 48 and 49 as well as asbestos wool 50, which can be covered with a Verachlußmasae 51. a commercially available, unilaterally closed ceramic tube made from 80% by mass of AlpOo and 20% by mass of SiO _2, with pores predominantly 5 to 10 μm wide, in which a bore is made.

In order to extend the operating time of the probes by keeping out vaporous impurities, the free space around the measuring electrodes is filled with loaen pieces of 0.5 to 2.0 mm thickness of completely tightly sintered atabilized zirconium dioxide ala adsorbent or absorbent. The pieces must not be too fine and not porous in order to avoid inertia of the probe due to the adsorption and deactivation of analytical gas.

The heating furnace 42 is shown in section in FIG. 8 and in top view on an end face in Fig. 8a shown in more detail · In Fig. 8a you can see the transitions of the heating spiral between the holes, whereby 2 of 16 holes remain free. Which deepens Transitions of the heating spiral lying in a groove are smeared on both sides with a protective maaaae.

The longitudinal section through the heating furnace perpendicular to that in FIG. 8 is shown in FIG. 9, wherein, as in FIG. 7, the bores left free by the heating coil are visible. In contrast to FIG. 7, FIG. 9 shows gas passage openings in the end region of the furnace. The cell shown has a solid electrolyte tube closed on one side with a sealing compound 52. In this case, the reference gas is supplied through a gas line 53 and flows backwards into the guide tube 13. Fig. 9a shows the changes required to the multiple capillary tube piece 54 in order to be able to attach the gas line and enable the gas return flow (cf. Fig. 1a) If the gas pipe 53 is made of the same corrosion-resistant metal as the jacket of the thermocouple 40, the two bores can also be used as electrical lines to the inner and outer electrodes.

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-X-

S3 29U947

The installation of a probe with connection piece in the Yfend 55 an analysis gas space is finally made up of Pig. 10 can be seen. The fastening is e.g. easy with a union nut 56 possible. The probe is in the protective tube 57 » E.g. made of Sichromal steel, with incisions 58 and gas guiding devices 59 to improve the gas purging and the prevention of fly ash · FIG. 10a clarifies the incisions and the gas guide device in a plan view of the end of the probe.

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Claims (3)

Claims Device for gas analysis -; it galvanic solid electrolysis cells, which contains a hollow body with ionic conductivity and electrodes as a cell arrangement, with an electric furnace being optionally located in the area of the electrodes around the hollow body, using potentioaxial, amperometric and coulemetric measuring methods As well as utilizing catalytic effects, the fact that the hollow body, which can also have different ionic conductivity - referred to below as the base body (1) on the outside, has several separate measuring electrodes (21) and is located in this base body ( 1) a reference system (10) or several (32), different reference systems lying opposite läeßelectrodes, the Dralitz supply lines (4-; 22; 11; 33) to the individual electrodes with the help of hats (5) and feedthroughs through holes (6) one end of the base body (1) and through a multiple capillary tube piece (7) with a bolt (9) or on the wire feed lines (4 -; 22; 11; 33) attached corrosion-resistant parts (18; 19; 20) are secured against tension, pressure and torsion on the base body (1) and that the base body (1) with the electrodes and the connected lines to a gas-tight guide tube (13) coaxially with the help a glass or a sintered mass (12) is attached gas-tight and inserted together with the guide tube (13)> with temperature sensor (4-0) and test gas line (41) into a porous, filter-acting ceramic tube (34) with a closed or drilled bottom is. 2. Device according to claim 1, characterized in that the lines are laid from the measuring electrodes (2; 21) to the end of the base body (T) which connects to the gas-tight guide tube (13), that they are there through bores (6 ) in the base body (1) perpendicular to its axis in notches (5) made on the outside along the base body (1) or thinned on the outside 03 0 0-1 1/05 3 5 c - Place in the inside of the green body pipe (1) υπό are then guided to the guide tube (13) , v / obei the lines (4- · 22) are each before and after the bore xe angles of about 9o ° jebofren. Device according to claim 1 and 2, characterized in that the teaching capillary tube piece (7) on an end face of a; RLe ^ eI (9), which engages in Lu ten ir, the stirrup of the facing, Et.aes of the basic body (1), that -through -He capillary of the I. multiple capillary tube piece (7) individually Jie electrical lines of inner and outer electrodes (11 · 4) are laid so that there are corrosion-resistant parts attached to electrical lines of Iunenplektrocen directly in front of the point of passage through capillary bends or bends, so that electrical lines are immediately behind the points of passage through capillaries or bends Corrosion-resistant parts (18 19; 2o) are located Device according to Claims 1 to 3, characterized in that the base body (1) and the guide tube (13) differ only slightly from one another in terms of the external coefficient, are ground to fit together (17) or otherwise appropriately verior-nt and i ;; it is connected to a sealing compound (12), the expansion coefficient of which lies primarily between that of the base body (1) and that of the guide tube (13). Device according to Claims 1 to 4, characterized in that parts of the base body (1) for large to small oxygen partial pressures consist of an oxiaionenieitenden solid electrolyte primarily on the basis of the stabilized zirconium dioxide , that parts of the base Body (1) exclusively for the measurement of high oxygen partial pressures consists primarily of porous, electrically non-conductive ceramic bodies, in which the pores are impregnated with solid electrolytes L; , nitrogen-oxide-containing or carbon-containing gases primarily from porous, electrically non- 030011 / 053S BATH ORIGINAL -5- 29U947 conductive Kerar.; ikbodies are built up in the en aie Pore kit such salts are impregnated, their aniooea i: it deiü to be determined analytically, the gaseous oxide or i :: it is the connection to be recorded analytically Gaseous oxide formed by oxidation with exchange of electrons with * era electrode metal -sov; ie Kit oxygen to enter into an electrolyte reaction from the bleeding gas capital. 6. The device still claims 1 to 5> characterized ze characterizing aei chn et _t that the Iceßelcktroden εit (2 x 21) alloy of porous layers or unalloyed platinum metals or exist without admixture oxidic substances or of porous layers of silver, gold or alloys thereof and that for contacting structures made of wire, sheet metal or wire mesh, primarily made of the same noble metal, attached to it, and the electrical lines (4-; 22) are welded in the form of non-scaling wires. 7. Device according to claim 1 to 6, characterized in that the reference electrodes (1o · 32) in the interior of the tubular base body (1) constructed like the Keßelectrodes or made of an electron-conducting oxide layer with contact ^! : made of metallic structures and determined by a propellant gas, primarily air or air! Content of SOp, KO ^ or 00 ₂ »are surrounded. 8. Device according to claim 1 to 6, characterized in that the reference system for cells for Kessung gaseous oxides inside on the impregnated with pure salt ceramic body from a layer formed from the salt in question with the addition of a silver salt, a silver layer on top and one contacting metallic structure insists \ ind is constantly flooded with air. 9. Device according to Claim 8, characterized in that the measuring gas space and reference electrode space are connected to one another via a capillary (15) at the end of the base body (1) free of electrical lines. 0300 BATH ORIGINAL 29U947 10. Device according to claim 1 to 9, characterized in that the electrodes (24 · 25) are designed over a large area for the execution of amperometric or couloEetric Feßve and the? Feßgas facing outer electrode (24) is given by a tubular hollow body (26) which is attached to the base body (1) in a gas-tight manner on the side of the electrical supply lines using Mchtur.GSir.asse (12) . . & on the other side the base body (1) except for the iron Gosdurcht-attsspalt (28), the gas passage of which can be restricted by the introduction of a porous cement. 11. Device according to claim 1 to 1o, characterized in that the electric furnace (42) for heating uer solid electrolyte cells at un aur egg hurrying ambient temperatures from a ceramic tube prehelich kit 16 LUngsbohrungen in the Rohrv / aud that through 14 of these holes of the heating conductor it is carried out that the remaining bores are opposite each other and accommodate the required number of thermocouples (40 · 43) and that incisions and cross bores are made in the two bores without heating conductors for the passage of l'eßgas. 12. Device according to claim 1 to 11, characterized in that for setting different temperatures at different Feßelektroänen (2; 21) these each in the I.'itte of different ovens or en places in Teir.peraturverläne a furnace η it oe :. · Stored at the desired temperatures and brought under control by appropriately stored Therroelecents (4o · 4J). 13. Device according to claim 1 to 12, dadur cb geke η η ze ichn et that acting as a filter, i.ie named probe parts enclosing ceramic tube (34) pores ir.it widths up to J> o / um, primarily vou 5 to io, in order to have an opening made in the bottom of the ceramic filter tube closed on one side for inserting the reference gas outlet capillary (15), that the ceramic filter tube (34) for protection in a ceramic tube (57) or scale-proof metal tube 03001 1/0535 BATH ORIGINAL 29U947 Gas duct equipment (59) and gas passage openings (58) and thus directly into the room with your analysis or is built into an arrangement for taking cross-sectional samples. 14. Device according to claim 1 to 8 unu. 1o to 13, characterized in that _y admissibility of the discharge of flowing through the reference electrode gas in the gas analysis Raue the base body (1) to the; End closed without electrical lines by a sealing compound (52), the filter tube is not pierced at the bottom and a tube (53) is placed through a notch in the waste capillary tube (54) to allow gas to be pressed into the electrode space. 15 · Device according to claim 1 to 14, characterized in that the space inside the ceramic filter tube 04) around the Feßelectrodec on the side of the outflowing reference gas and on the opposite side by parts made of ceramic (48 · 49) or oxyäischem fiber material (46 · 47; 5o) is limited and largely sealed against dust. 16. Device according to claim 1 to 15, characterized in that the Keßelectrodes are encased in such a way by parts of the oven or by Keraraikrohren that suspended particles that have penetrated the probe do not fall on the Eeßelectrode and the measuring gas only diffuses horizontally to the KeßeIrodes can. 17. Device according to claims 1 to 16, characterized in that the free space between the feet electrodes and the ceramic filter tube is completely or partially filled with loose pieces 0.5 to 2.0 mm thick made of gastight sintered magnesium oxide or stabilized zirconium dioxide. 18. Device according to claim 1 to 6, 8 and 9, 11 to 1J, 15 to 17 » characterized in that a multifunctional solid electrolyte gas sensor specifically for measurements on flue gases from combustion systems Βλίε a tube made of oxidic solid electrolyte (1), outside with de a measuring electrode (2 · 21) 3 0 0 11/0535 BATH ORIGINAL made of platinum (I) and gold (H) as well as inside with an I and II opposite reference electrode (1o) made of platinum (III), and from a porous ceramic tube with potassium sulfate in the pores, on the outside with a platinum electrode (17) and on the inside with a reference electrode (Y) Potassium sulphate with 1 L'asse-% silver sulphate and "inner layer (31) Silver (32) is put together so that this arrangement of solid electrolyte tube parts (1 j 29) is gas-tight to a Guide tube (13) is attached, contains clean air inside and outside of an electric furnace (42) and filter tube (34) is so surrounded that dust-cleaned belly gas diffuse up to the I / Ießelectrodes I, II and IV can, and that electronic devices for measuring oxygen with electrodes I and III, for the detection of unburned Gas components ir. With electrodes I and II and for the boiler of sulfur dioxide and trioxide with electrodes I, III, IV and V are connected in the appropriate manner to form the desired signals. 19 · Device according to claim 1 to 15, characterized in that a mono- or multifunctional solid electrolyte gas sensor especially for transportable devices for measuring gas partial pressures in a free atmosphere, on oxygen systems, in work rooms, mine shafts, etc., made of largely miniaturized parts, Mainly with a base body with an ^{outer diameter of 2 to 3 km} and is equipped with a micro-oven that keeps the sensor at the operating temperature with the help of a portable power source, as well as a reference gas reservoir if the ambient air is unusable as a reference gas kit. 2o. Device according to claims 1 to 19, characterized in that at the entry points of the gas for the reference system and the test gas there are replaceable gas filters as well as devices for the connection of floating cone devices (botameters) for permanent or temporary control of the gas flow rate. 030011/0535 BATH ORIGINAL