DE1298312B

DE1298312B - Method for displaying the concentration of traces of oxygen in a gas mixture

Info

Publication number: DE1298312B
Application number: DE1963N0023281
Authority: DE
Inventors: Tomimoto Akio; Uzuki Busuke; Narita Yoshio
Original assignee: Japan Oxygen Co Ltd
Current assignee: Japan Oxygen Co Ltd
Priority date: 1963-05-31
Filing date: 1963-06-06
Publication date: 1969-06-26

Description

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Die Erfindung betrifft ein Verfahren zur Anzeige Gehalt an Spurensauerstoff des zu analysierenden der Konzentration von Sauerstoffspuren in einem Gasgemisches ab/ :. ' ■· ' ·The invention relates to a method for displaying trace oxygen content of the to be analyzed the concentration of traces of oxygen in a gas mixture from /:. '■ ·' ·

Gasgemisch, beruhend auf einer chemischen Um- Gelber Phosphor in fester Form hat einen Dampfsetzung des Sauerstoffs mit einer-Reaktionssubstanz. druck von 0,025 mm Quecksilbersäule bei 20° C. Zur Bestimmung der Konzentration von Sauer- 5 Wenn er daher unter atmosphärischem Druck mit stoffspuren in einem Gasgemisch ist bereits ein Ver- der Dampfphase in gesättigtem Gleichgewicht steht, fahren bekannt, bei dem unter Verwendung einer muß in der Atmosphäre der Reaktionskammer galvanischen Zelle das sauerstoffhaltige Gas in einem dampfförmiger gelber Phosphor in einer Konzen-Elektrolyten, z. B. NaOH, elektrochemisch analysiert tration von 33,3 ppm vorhanden sein. Unter Berückwird. Eine hierfür geeignete Anordnung besteht im io sichtigung der eingangs angezogenen Reaktionsformel wesentlichen aus einer, elektrolytischen Zelle, also entspricht dieser Wert einem Äquivalent von anaus einem den flüssigen Elektrolyten aufnehmenden nähernd 100 ppm Sauerstoff. Infolgedessen stehen Gefäß und zwei in den Elektrolyten eingetauchten auch bei gelbem Phosphor in festem Zustand der Elektroden, von welchen die Anode beispielsweise Gehalt an Sauerstoff im Gasgemisch und die bei der aus Silber und die Kathode beispielsweise aus Blei, 15 Reaktion auftretende Strahlungsintensität in propor-Cadmium od. dgl. besteht. Der in dieser galvanischen tionaler Beziehung zueinander. Nach Ermittlung des Zelle durch kathodische Reduktion des Sauerstoffs entsprechenden Proportionalitätsfaktors ist dann entstehende elektrische Strom ist in seiner Größe Spurensauerstoff von 0,01 ppm unschwer nach dem proportional dem Gehalt des im Elektrolyten ge- erfindungsgemäßen Verfahren bestimmbar. Speziell lösten Sauerstoffs. Die lineare Beziehung zwischen 20 ist auch ein sehr geringer Gehalt an Spurensauerstoff dem elektrischen Strom und der Sauerstoffkonzen- von 1 ppm schnell und exakt meßbar, tration im Elektrolyten gilt selbstverständlich nur für Nachstehend wird ein Ausführungsbeispiel einerGas mixture, based on a chemical conversion, yellow phosphorus in solid form has a vapor deposition of oxygen with a reaction substance. pressure of 0.025 mm of mercury at 20 ° C. To determine the concentration of Sauer- 5 when using it therefore under atmospheric pressure traces of substance in a gas mixture is already a change in the vapor phase is in saturated equilibrium, drive known in which using a must in the atmosphere of the reaction chamber galvanic cell the oxygen-containing gas in a vaporous yellow phosphorus in a concentrated electrolyte, z. B. NaOH, electrochemically analyzed tration of 33.3 ppm may be present. Under consideration. A suitable arrangement for this consists in viewing the reaction formula cited at the outset essentially from an electrolytic cell, so this value corresponds to an equivalent of anaus an oxygen absorbing the liquid electrolyte approximately 100 ppm. As a result, stand Vessel and two immersed in the electrolyte even with yellow phosphorus in the solid state Electrodes, of which the anode, for example, content of oxygen in the gas mixture and the of silver and the cathode, for example, of lead, 15 reaction occurring radiation intensity in propor-cadmium or the like. The one in this galvanic tional relation to one another. After determining the Cell by cathodic reduction of the oxygen corresponding proportionality factor is then The resulting electric current is not difficult in its size after the trace oxygen of 0.01 ppm can be determined proportionally to the content of the method according to the invention in the electrolyte. Special dissolved oxygen. The linear relationship between 20 is also a very low trace oxygen content the electrical current and the oxygen concentration of 1 ppm can be measured quickly and precisely, Tration in the electrolyte applies of course only to the following is an embodiment of a

einen gewissen Bereich. Vorrichtung zur Durchführung des erfindungs-a certain area. Device for carrying out the invention

Nach einem anderen Verfahren wird ein beson- gemäßen Verfahrens an Hand der Zeichnungen im derer Katalysator, der im wesentlichen aus Platin— 25 einzelnen erläutert; es zeigtAccording to another method, a specific method is carried out using the drawings in that catalyst, consisting essentially of platinum - 25 individual ones; it shows

Palladium besteht, eingesetzt und mit Hilfe dieses A b b. 1 den Schaltplan einer Vorrichtung zur BeKatalysators der im Gas enthaltene Sauerstoff mit Stimmung der Konzentration von Sauerstoffspuren, Wasserstoff zur Reaktion gebracht. Die entstandene Abb. 2 einen Längsschnitt durch die Reaktions-Palladium is used, and with the help of this A b b. 1 the circuit diagram of a device for BeKatalysators the oxygen contained in the gas with mood of the concentration of oxygen traces, Reacting hydrogen. The resulting Fig. 2 is a longitudinal section through the reaction

Reaktionswärme wird gemessen und dient als Maß kammer der Vorrichtung nach Abb. 1, für die im Gas enthaltene Sauerstoffmenge. Es ist 30 A b b. 3 ein Diagramm, aus welchem die Überauch bekannt, eine Farbsubstanz, wie beispielsweise einstimmung zwischen den mittels einer Eichvorrich-Anthraquinon-/?-sulfonat mit den im Gas enthaltenen rung und den mittels Standardgas erhaltenen Strom-Sauerstoffspuren .zur Reaktion zu bringen, wobei die werten ersichtlich ist,The heat of reaction is measured and serves as the measurement chamber of the device according to Fig. 1, for the amount of oxygen contained in the gas. It's 30 A b b. 3 a diagram from which the Überauch known, a color substance, such as agreement between the anthraquinone - /? - sulfonate by means of a calibration device with the tion contained in the gas and the current oxygen traces obtained by means of standard gas .to react, whereby the values can be seen,

beispielsweise rote Farbe der Reaktionssubstanz ent- Abb. 4 ein Diagramm, welches die BeziehungFor example, the red color of the reaction substance is shown in Fig. 4 a diagram showing the relationship

färbt wird. Das Maß der Farbänderung wird mittels 35 zwischen der Durchflußgeschwindigkeit und dem abeines Colorimeters gemessen. gegebenen Meßstrom darstellt, undis colored. The degree of color change is determined by means of 35 between the flow rate and the abeines Colorimeters measured. represents the given measuring current, and

Die Durchführung der oben beschriebenen Ver- A b b. 5 ein Diagramm, aus welchem die BeziehungThe implementation of the A b b. 5 is a diagram from which the relationship

fahren dauert im allgemeinen reichlich lange. Bei zwischen dem Gehalt an Spurensauerstoff und dem einer 100%ig sicheren Bestimmung wird regelmäßig abgegebenen Meßstrom ersichtlich ist. eine Zeitspanne von etwa einigen Minuten bis zu 40 Das in der A b b. 1 dargestellte Gerät zur Anzeige einer Stunde benötigt. — Hier will die Erfindung der Konzentration von Sauerstoffspuren in einem Abhilfe schaffen. Gasgemisch beruht auf der Messung der IntensitätDriving generally takes a long time. With between the content of trace oxygen and the a 100% reliable determination will be able to see the measured current delivered regularly. a period of about a few minutes up to 40 The in the A b b. 1 shown device for display takes an hour. - This is where the invention of the concentration of traces of oxygen in one To remedy the situation. Gas mixture is based on the measurement of the intensity

Der Erfindung liegt die Aufgabe zugrunde, ein der bei der Oxydation von Phosphor emittierten Verfahren anzugeben, nach dem die Konzentration Strahlung und besteht im wesentlichen aus einer in von Sauerstoffspurem in einem Gasgemisch schnell 45 Abb. 2 im einzelnen dargestellten Reaktionskam- und exakt bestimmt werden kann. mer 7 für das Gasgemisch, in der sich gelber Phos-The invention is based on the problem of one of those emitted during the oxidation of phosphorus Method to indicate according to which the concentration radiation and consists essentially of an in of oxygen traces in a gas mixture quickly 45 Fig. 2 individually shown reaction chambers and can be determined exactly. mer 7 for the gas mixture in which yellow phos-

Diese Aufgabe löst die Erfindung bei einem Ver- phor 18 in flüssiger oder fester Form befindet und an fahren zur Anzeige der Konzentration von Sauer- die eine fotoelektrische Einrichtung 23 zur Messung stoffspuren in einem Gasgemisch der eingangs be- der Intensität der emittierten Strahlung angeschlossen schriebenen Art dadurch, daß die Umsetzung in der 50 ist. Die Reaktionskammer 7 ist als Durchflußkammer Oxydation von gelbem Phosphor besteht und die für das Gasgemisch ausgebildet und hierzu mit einem Intensität der hierbei emittierten Strahlung photo- Gaseinlaß 17 und einem Gasauslaß 20 versehen soelektrisch gemessen wird. wie mit einem Gasdurchflußmesser 4 in Reihe ge-This object is achieved by the invention in the case of a phosphor 18 in liquid or solid form drive to display the concentration of acid which a photoelectric device 23 for measurement Substance traces in a gas mixture which are initially connected to the intensity of the emitted radiation kind of written by the fact that the implementation is in the 50th. The reaction chamber 7 is a flow chamber There is oxidation of yellow phosphorus and which is formed for the gas mixture and for this purpose with a Intensity of the radiation emitted in this case photo gas inlet 17 and a gas outlet 20 provided soelectrically is measured. as with a gas flow meter 4 in series

Die unter Lichterscheinungen ablaufende ehe- schaltet. Der Gaseinlaß 17 mündet innerhalb der mische Reaktion zwischen gelbem Phosphor und 55 Reaktionskammer 7 in einer Düse, die auf den in Spurensauerstoff in der Reaktionskarnmer geht nicht einem Behälter 16 befindlichen gelben Phosphor 18 als direkte Reaktion zwischen dem festen oder flüs- gerichtet ist. Die fotoelektrische Einrichtung 23, die sigen gelben Phosphor und dem Spurensauerstoff, im Ausführungsbeispiel aus einem Sekundär-Eleksondern stets als eine Reaktion zwischen dampf- tronen-Vervielfacher besteht, aber auch ein Fotoförmigem gelbem Phosphor P₄ und dem Spuren- 60 transistor sein kann, ist hinter einer die Reaktionssauerstoff vor sich, gemäß nachstehender Formel: kammer 7 abschließenden Glasscheibe 21 angeordnet ρ -t-3O=2PO ^unc* ^urch ^eme Hülse24 gegen Fremdlicht abge-^{4 2 2 3} schirmt. Die Innenwandungen der Reaktionskam-Dementsprechend ist der in der Reaktionskammer mer 7, die aus einem Rohr 19 und einer Abschlußvorhandene feste oder flüssige gelbe Phosphor ledig- 65 platte 25 besteht, besitzen eine reflektierende Schicht, lieh als Quelle für den dampfförmigen gelben Phos- die je nach den Verhältnissen unterschiedlichen phor anzusehen. Ob dabei fester oder flüssiger gelber Reflexionsgrad aufweisen kann. In der Reaktions-Phosphor verwendet wird, hängt allein von dem kammer? ist eine Eichglühlampe26 angeordnet,The marriage, which takes place under light phenomena. The gas inlet 17 opens within the mixed reaction between yellow phosphorus and reaction chamber 7 in a nozzle which is directed to the yellow phosphorus 18 located in trace oxygen in the reaction chamber not in a container 16 as a direct reaction between the solid or liquid. The photoelectric device 23, which consists of yellow phosphorus and trace oxygen, in the exemplary embodiment consists of a secondary electron always as a reaction between vapor-electron multipliers, but can also be a photo-shaped yellow phosphorus P ₄ and the trace transistor behind a reaction of oxygen on, according to the following formula: disposed chamber 7 final glass sheet 21 -t-3O = 2PO ^unc * ^ ρ shields urch ^eme Hülse24 to ambient light off ^{2 4 2. 3} The inner walls of the reaction chamber - accordingly, the one in the reaction chamber 7, which consists of a tube 19 and a sealing solid or liquid yellow phosphor single plate 25 - have a reflective layer, borrowed as a source for the vaporous yellow phosphorus to consider different phor according to the circumstances. Whether solid or liquid can have yellow reflectance. In the reaction phosphorus is used depends solely on the chamber? a calibration incandescent lamp26 is arranged,

Claims

3 43 4

whose radiation intensity can be regulated via its current by means of mer 7 for the further passage of the gas mixture potentiometer 29 and 30 and voltage selector 12 with resistors RS to R8 from which, in a manner to be described, serves to calibrate phors due to impure gas with too high a content and setting of the device . At the exit to trace oxygen prevented or the photo verifier photoelectric device 23 is connected via a 5 stronger from destruction or fatigue due to sensitivity selector 8, a measuring device 9 from the high oxygen content of the gas, which has a limit switch 14 in the gas - Protected resulting high radiation intensity, inlet 17 and in the gas outlet 20 of the reaction chamber- The basic setting and calibration of the device mer 7 arranged shut-off valves 2, S operated. This is done by using standard gas, the gas shut-off valve 2 in the gas inlet is known as the three-io content of trace oxygen, although the third way is a further setting and recalibration without this gas purging gas bridging the reaction chamber 7 the calibration incandescent lamp 26 can take place, line 3 is connected. The gas shut-off valves 2.5 If the radiation intensity of the calibration incandescent lamp 26 are designed as electromagnetic valves, which by means of appropriate setting of the variable via a the limit switch 14 of the measuring device 9 15 resistors 29 and 30 with the radiation intensity containing circuit from an alternating voltage when the standard gas is blown through be fed by the source 15. In this circuit there is also a step switch 13, which corresponds to the reaction chamber and which corresponds to a voltage selector 12 once set, with the value of the radiation intensity by pressing a switch 27 in the circuit of the calibration lamp and by 11 taken operating voltage for the fotoelek- setting the pointer setting on the measuring device 9 mittrische device 23 can be set. By means of a potentiometer R 9, the initial calibration achieved with the aid of the standard gas can be rewritten as follows: Before starting a measurement, this must be set. The gas mixture analyzed by this calibration device through a gas supply 1, 25 after the setting has been made, and the three-way shut-off valve 2, the flushing line 3 and the calibration gas discharge 6 achieved by using standard gas, so that the gas display are alternately in A b b . 3 shown, intake system remaining air completely out- The relationship between the flow rate is pushed out. Then the step switch 13 is activated by the reaction chamber together with the voltage selector 12, 30 mer 7 and the output measuring current in the device, whereby the three-way shut-off valve 2 is the path for a straight line (Fig. 4), so that the sensitivity is also the gas mixture through the flow meter by changing the flow rate in the reaction chamber. At the same time, speed can be controlled. Accordingly, the shut-off valve 5 is opened so that the gas mixture can flow through the reaction chamber if a maximum electrical value is selected. 35 Sensitivity, the flow rate is high The emerging from the nozzle of the gas inlet 17 and consequently a wide reaction gas mixture jet is selected on the yellow phosphor 18 chamber quantitative vapor determination. The fact that between the phosphorous formation of a very low content of trace acid vapor and the trace substance present in the gas mixture below 1 ppb is possible; the chemical reaction that has hitherto usually taken place with oxygen could not be analyzed.

The relationship between trace oxygen and the penetration of the glass plate 21 on a light emitted measuring current is shown, for example, in Fig. 5 sensitive surface 22 of the photo amplifier 23 impinges. As this figure shows, the pro-and here causes a photoelectric effect. 45 Portionality between the output measured flow and the flow rate of the gas mixture in trace oxygen of known concentration right near the reaction chamber is usually selected to be excellent. The device responds very quickly. that the reaction between the yellow phosphorus is also like A b b. 4 shows, in the case of the device, steam and the trace oxygen is terminated, since the output signal has inevitably reached the zero value before the gas mixture reaches the gas outlet 20 of the reaction 50 by stopping the gas flow, a nucleation chamber 7. The operating voltage setting with gas without any oxygen for the photo amplifier 23 is not absolutely necessary to control it. This property is sensitivity according to the intensity of the of particular importance and above all then un-luminous phenomena adjusted, for which the span is required if a determination of voltage selector 12 with resistors R 5 to R 8 from trace oxygen below 1 ppb is to be achieved , is prepared. The output measuring current of the photo amplifier is transmitted to the measuring device 9 by the sensitivity selector 8 with resistors R 1 to R 4 in

corresponding division supplied. This cons-method to display the concentration of

levels can be selected, for example, so that there are 60 traces of oxygen in a gas mixture, based

for the trace oxygen display ranges of 50 ppm, based on a chemical conversion of the oxygen

20 ppm, 1 ppm and 100 ppm in the measuring device 9 result. with a reaction substance, thereby g e -

At the end of the deflection of the measuring device 9, the end indicates that the implementation in the

switch 14 operated, which is a switch of the three-oxidation of yellow phosphorus and the

way shut-off valve 2 and a closing of the blocking 65 intensity of the radiation emitted in this way photo-

valve 5 has the consequence, so that the reaction chamber is measured electrically.

For this purpose 2 sheets of drawings