DK154458B - METHOD OF PAINTING WITH REDOX OR ION SENSITIVE ELECTRODES - Google Patents
METHOD OF PAINTING WITH REDOX OR ION SENSITIVE ELECTRODES Download PDFInfo
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- DK154458B DK154458B DK179980AA DK179980A DK154458B DK 154458 B DK154458 B DK 154458B DK 179980A A DK179980A A DK 179980AA DK 179980 A DK179980 A DK 179980A DK 154458 B DK154458 B DK 154458B
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- 238000000034 method Methods 0.000 title claims description 38
- MHAJPDPJQMAIIY-UHFFFAOYSA-N Hydrogen peroxide Chemical compound OO MHAJPDPJQMAIIY-UHFFFAOYSA-N 0.000 claims description 43
- 238000005259 measurement Methods 0.000 claims description 43
- 239000000243 solution Substances 0.000 claims description 31
- 239000003153 chemical reaction reagent Substances 0.000 claims description 30
- 238000006243 chemical reaction Methods 0.000 claims description 27
- XFXPMWWXUTWYJX-UHFFFAOYSA-N Cyanide Chemical compound N#[C-] XFXPMWWXUTWYJX-UHFFFAOYSA-N 0.000 claims description 25
- 150000002500 ions Chemical class 0.000 claims description 15
- 238000001311 chemical methods and process Methods 0.000 claims description 7
- 150000001875 compounds Chemical class 0.000 claims description 3
- 239000007864 aqueous solution Substances 0.000 claims description 2
- 230000000737 periodic effect Effects 0.000 claims description 2
- 239000002351 wastewater Substances 0.000 description 9
- 238000002474 experimental method Methods 0.000 description 4
- 238000012544 monitoring process Methods 0.000 description 4
- 239000003054 catalyst Substances 0.000 description 3
- XLJMAIOERFSOGZ-UHFFFAOYSA-M cyanate Chemical compound [O-]C#N XLJMAIOERFSOGZ-UHFFFAOYSA-M 0.000 description 3
- 230000003111 delayed effect Effects 0.000 description 3
- 238000001784 detoxification Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 239000002253 acid Substances 0.000 description 2
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 2
- 238000011437 continuous method Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- -1 ion ion Chemical class 0.000 description 2
- 150000002825 nitriles Chemical class 0.000 description 2
- 239000001301 oxygen Substances 0.000 description 2
- 229910052760 oxygen Inorganic materials 0.000 description 2
- 239000000126 substance Substances 0.000 description 2
- 238000012360 testing method Methods 0.000 description 2
- WZZBNLYBHUDSHF-DHLKQENFSA-N 1-[(3s,4s)-4-[8-(2-chloro-4-pyrimidin-2-yloxyphenyl)-7-fluoro-2-methylimidazo[4,5-c]quinolin-1-yl]-3-fluoropiperidin-1-yl]-2-hydroxyethanone Chemical compound CC1=NC2=CN=C3C=C(F)C(C=4C(=CC(OC=5N=CC=CN=5)=CC=4)Cl)=CC3=C2N1[C@H]1CCN(C(=O)CO)C[C@@H]1F WZZBNLYBHUDSHF-DHLKQENFSA-N 0.000 description 1
- FOIXSVOLVBLSDH-UHFFFAOYSA-N Silver ion Chemical compound [Ag+] FOIXSVOLVBLSDH-UHFFFAOYSA-N 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000012190 activator Substances 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 238000013459 approach Methods 0.000 description 1
- 239000000337 buffer salt Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000006073 displacement reaction Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000002452 interceptive effect Effects 0.000 description 1
- 230000001788 irregular Effects 0.000 description 1
- 239000000203 mixture Substances 0.000 description 1
- 238000004313 potentiometry Methods 0.000 description 1
- 108090000623 proteins and genes Proteins 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 239000012429 reaction media Substances 0.000 description 1
- 230000002441 reversible effect Effects 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 230000002269 spontaneous effect Effects 0.000 description 1
- 238000011410 subtraction method Methods 0.000 description 1
- 230000002123 temporal effect Effects 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/26—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating electrochemical variables; by using electrolysis or electrophoresis
- G01N27/416—Systems
- G01N27/4163—Systems checking the operation of, or calibrating, the measuring apparatus
- G01N27/4165—Systems checking the operation of, or calibrating, the measuring apparatus for pH meters
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- Chemical & Material Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Health & Medical Sciences (AREA)
- Physics & Mathematics (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Molecular Biology (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
- Investigating Or Analysing Biological Materials (AREA)
Description
DK 154458BDK 154458B
iin
Det er kendt, at der ved målinger frem for alt med.redox- eller ionfølsomme elektroder optræder forandringer ved elektroderne, . og at der forekommer poténtial-forskydninger, f.eks. på grund af forstyrrende ioner.It is known that for measurements above all with redox or ion sensitive electrodes, changes occur at the electrodes,. and that potential shifts occur, e.g. due to disruptive ions.
5 Et til kontinuert gennemførelse af kemiske frem gangsmåder med potentiometrisk overvågning meget ubehageligt, fænomen - er f.eks. målekædens potentialdrift, der normalt ved potentriometrisk overvågning af diskontinuerte fremgangsmåder på grund af det til en hver tid en-10 kelte korte måletidsrum ikke tages i betragtning.5 A very unpleasant, continuous phenomenon of chemical processes with potentiometric monitoring, phenomenon - is e.g. the potential operation of the measuring chain, which is normally not taken into account by potentiometric monitoring of discontinuous methods due to the short measurement timescales, which are sometimes isolated at 10 times.
Netop muligheden for at kunne gennemføre potentialmålinger ved kontinuerte fremgangsmåder har for kemiske processer, der overvåges, styres og kontrolleres gennem disse poténtialmålinger, meget stor betydning, 15 frem for alt eftersom det ved mange tekniske fremgangsmåder drejer sig om systemer, hvori der optræder forstyrrende ioner eller andre forstyrrehde påvirkninger; såsom elektrodebelægninger, som f.eks. ved spildevandsafgift-ning.Precisely the possibility of conducting potential measurements by continuous methods has very important importance for chemical processes that are monitored, controlled and controlled through these potential measurements, 15 since in many technical approaches these are systems in which disruptive ions or other disturbing influences; such as electrode coatings, such as by wastewater taxation.
20 En overvågning af sådanne systemer ved fjernelse af prøver og disses afprøvning ved kemisk analyse i laboratoriet er i almindelighed overordentlig kostbar.Monitoring of such systems by removing samples and testing them by chemical analysis in the laboratory is generally extremely expensive.
Desuden er denne overvågningsmetode som kontrol for den sikre gennemførelse af en kemisk proces ikke altid acceptabel, 25 eftersom uforudsete driftssvingninger for det meste erkendes for sent.Furthermore, this monitoring method as a control for the safe implementation of a chemical process is not always acceptable, since unforeseen operational fluctuations are usually recognized too late.
Der kendes fremgangsmåder til direkte potentiometrisk måling af ionkoncentrationer. Ved disse såkaldte subtraktionsmetoder (jvf. Zeitschrift Anal. Chemie, 251, 30 1970, s. 1-6, Labo, okt. 1975, s. 883-884 og 888-889 samt K. Cammann "Das Arbeiten mit ionenselektiven Elektroden", Springer Verlag 1977, s. 139-140 og 190) måler man potentialet i den opløsning, hvor den pågældende ionkoncentration skal bestemmes, hvorefter man til en 35 afmålt mængde heraf tilsætter en lille, afmålt mængde af en opløsning, der indeholder ionen i en kendtukoncentration og gentager potentialmålingen.- Udfra forskellen i de målte potentialer kan man så beregne den søgte ion-Methods for direct potentiometric measurement of ion concentrations are known. In these so-called subtraction methods (cf. Zeitschrift Anal. Chemie, 251, 30 1970, pp. 1-6, Labo, Oct. 1975, pp. 883-884 and 888-889, and K. Cammann "Das Arbeiten mit ionenselektiv Electrode", Springer Verlag 1977, pp. 139-140 and 190) measures the potential of the solution at which the ion concentration in question is to be determined, and then a small, metered amount of a solution containing the ion in a known concentration is added and repeats the potential measurement.- From the difference in the measured potentials one can then calculate the ion ion sought-
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2 koncentration. Metoden er baseret på Nernst' ligning og kan ikke benyttes ved ionkoncentrationen nul, hvor denne ligning bliver meningsløs. Endvidere kan der ved benyttelse ved måling på kontinuerlige processer op-5 træde fejl på grund af potentialdrift.2 concentration. The method is based on Nernst's equation and cannot be used at zero ion concentration, where this equation becomes meaningless. Furthermore, when used in continuous process measurement, errors may occur due to potential operation.
I tysk offentliggørelsesskrift 2.018.514 beskrives fremgangsmåde med anvendelse af to elektroder, hvor den ene elektrode omskylles af en reagensopløsning, og den anden af den udreagerede blanding, og hvor man 10 måler potentialforskellen mellem elektroderne. Da de to elektroder befinder sig i’ forskellige opløsninger, vil de i tidens løb forgiftes forskelligt, og målingen bliver upålidelig.German Patent Specification 2,018,514 describes the method of using two electrodes, one electrode being rinsed by a reagent solution and the other of the unreacted mixture, and measuring the potential difference between the electrodes. As the two electrodes are in different solutions, they will be poisoned differently over time and the measurement becomes unreliable.
Den omhand.7 ede fremgangsmådes mål er derfor en 15 potentiometrisk me ode, hvorved den kontinuerlige gennemførelse af kemi&ke fremgangsmader, hvori der ma regnes med ubekendt, forstyrrende påvirkning på målekæden kan styres og overvåges.Therefore, the objective of the method of the present invention is a potentiometric method, whereby the continuous implementation of chemical processes in which unknown, interfering influence on the measurement chain can be expected can be controlled and monitored.
Det har nu vist sig, at man kan måle koncentra-20 tionen af en opløst komponent i en kemisk proces ved hjælp af en målekæde, der indeholder en redoxelektrode eller en ionselektiv elektrode, hvor målekædepotentia-lets nulpunkt underkastes forandringer under målingen, og ved periodevis tilsætning af et reagens, ved en frem-25 gangsmåde som er ejendommelig ved, at målingen foretages på en sidestrøm, idet opløsningens potential måles, hvorefter der tilsættes et reagens, der ikke i sig selv påvirker målekædens potential, og som fuldstændigt omsætter den pågældende komponent til en forbindelse, 30 der ikke eller kun i negligerbar grad påvirker målekædens potential, således at målekæden nu viser det potential, der svarertil koncentrationen 0 for komponenten, hvorfor forskellen mellem de to potentialer angiver den faktiske koncentration af den pågældende komponent.It has now been found that the concentration of a dissolved component in a chemical process can be measured by a measuring chain containing a redox electrode or an ion selective electrode, where the zero point of the measuring chain potential is subjected to changes during the measurement, and at periodic intervals. adding a reagent, in a method which is peculiar in that the measurement is carried out on a side stream, measuring the potential of the solution, then adding a reagent which does not in itself affect the potential of the measuring chain and completely converting the component concerned to a compound 30 that does not or only negligibly affect the potential of the measuring chain, so that the measuring chain now shows the potential corresponding to the concentration 0 for the component, and therefore the difference between the two potentials indicates the actual concentration of the component concerned.
35 Reagenset skal tilsættes i en mængde, der mindst svarer til den, der er nødvendig til omsætning af den målte komponent, fortrinsvis i et overskud.The reagent should be added in an amount at least equal to that required for reaction of the measured component, preferably in excess.
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Sekvensen for fremgangsmåden ifølge opfindelsen er ikke indskrænket til rækkefølgen "måling af potentialet for den øjeblikkelige koncentration - måling af O-potentialet".The sequence of the process according to the invention is not limited to the order "measuring the potential of the instantaneous concentration - measuring the O-potential".
5 Der kan også gås frem i den omvendte rækkefølge, dvs. man begynder med indstilling af O-potentialet og måler efter et forud valgt tidsrum den øjeblikkelige koncentration af den pågældende komponent.5 In the reverse order, ie. one starts with setting the O-potential and, after a preselected period, measures the instantaneous concentration of the component concerned.
Sekvensen gentages fortrinsvis cyclisk, hvorved 10 den ikke ubetinget hver gang skal føres til ende, dvs. man begynder f.eks. med måling af O-potentialet og slutter efter forløb af en eller flere sekvenser med O-potentialet.The sequence is preferably repeated cyclically whereby it does not have to be terminated unconditionally each time, ie. one begins e.g. with the measurement of the O potential and ending after the passage of one or more sequences with the O potential.
Reagenset, der fuldstændigt omsætter den kompo-15 nent, der skal måles, således at denne komponent.The reagent which completely converts the component to be measured so that this component.
til tidspunktet for O-punktsmålingen ikke mere er tilstede i reaktionsmediet, skal vælges således,at hverken reagenset eller den tilbageblivende forbindelse med den pågældende komponent forandrer målekædens potential.until the time of the O-spot measurement is no longer present in the reaction medium, it must be chosen so that neither the reagent nor the residual compound with the component concerned changes the potential of the measurement chain.
20 Medens reagenset, der kan komme på tale for en hel. række komponenter, der skal måles, allerede kan udvælges gennem kendskabet til deres alment ...kendte egenskaber, samt egenskaberne af reagenset, der tilsættes, og af den opståede forbindelse, er det i andre tilfælde 25 anbefalelsesværdigt at udføre et kontrolforsøg med det påtænkte reagens.20 While the reagent that may come up for a whole. a variety of components to be measured can already be selected through the knowledge of their generally known properties, as well as the properties of the reagent being added and of the compound formed, in other cases it is advisable to carry out a control experiment with the intended reagent. .
Som passende reagens f.eks. til måling af hydrogenioner i det sure såvel som det alkaliske område,har de hertil kendte puffersaltopløsninger af stærke baser/ 30 svage syrer henholdsvis svage syrei/stærke baser vist sig egnede.As a suitable reagent e.g. For the measurement of hydrogen ions in the acidic as well as the alkaline region, the known buffer salt solutions of strong bases / weak acids and weak acid / strong bases, respectively, have proved suitable.
Også ved bestemmelsen af de mindste mængder skadelige stoffer i det så vigtige spildevandsrensningsområde volder udvælgelsen af det pågældende reagens i al-35 mindelighed ingen vanskeligheder.In the determination of the smallest quantities of harmful substances in the so important wastewater treatment area, the selection of the reagent in question generally does not present any difficulty.
Således kan frem for alt bestemmelsen af de mindste mængder cyanidioner ved hjælp af hydrogenperoxidThus, above all, the determination of the smallest amounts of cyanide ions can be by hydrogen peroxide
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4 fastlægges upåklageligt ved nulpunktsdrift eller andre forstyrrende påvirkninger på potentialet.4 is determined impeccably by zero point operation or other disturbing effects on the potential.
Til nærmere belysning af opfindelsen er der gået nærmere ind på denne sidstnævnte fremgangsmåde .In order to elucidate the invention, this latter method is discussed in more detail.
5 -5 -
Det er et kendt fænomen, der frem for alt gør sig afgørende bemærket ved kontinuerlig gennemførelse af processer, at en målekaades nulpunkt forskyder sig fra det oprindelige indstillingsområde under målingen, dvs. at 10 nulpunktet driver, se M. Hofton - Coptinuous Determination of Free Cyanide in Effluents Using Silver Ion Se-" lective Elefctrode, - Environmental,bind 10 (1976) 3, 277/280.It is a known phenomenon that, above all, is decisively noticed in the continuous execution of processes, that the zero point of a measurement code deviates from the original setting range during the measurement, ie. at 10 the zero point driver, see M. Hofton - Coptinuous Determination of Free Cyanide in Effluents Using Silver Ion Se- lective Elefctrode, - Environmental, Vol. 10 (1976) 3, 277/280.
De påvirkninger, der fremkalder dette fænomen 15 er i mange tilfæld ikke kendte.The effects that cause this phenomenon 15 are in many cases unknown.
Upåklagelig^. potentiometriske koncentrationsmålinger er ikke mulige i sådanne systemer.Impeccable ^. potentiometric concentration measurements are not possible in such systems.
Ifølge fremgangsmåden i DE-PS 23 52 856 kan koncentrationen af cyanider og nitriler i spildevand 20 effektivt nedsættes med hydrogenperoxid og en speciel katalysator til mængder under 0,1 mg/liter.According to the process of DE-PS 23 52 856, the concentration of cyanides and nitriles in wastewater 20 can be effectively reduced with hydrogen peroxide and a special catalyst for amounts below 0.1 mg / liter.
Opnåelsen af cyanidionslutkoncentrationen fastlægges potentiometrisk.The achievement of the cyanide ion final concentration is determined potentiometric.
Herved viste det sig, at redox-potentialets nul-25 punkt ved kontinuerlig gennemførelse af afgiftning af dette spildevand langsomt forskydes.In doing so, it was found that the zero-point of redox potential in the continuous implementation of detoxification of this wastewater is slowly shifted.
Ved anvendelse af fremgangsmåden ifølge opfindelsen, hvorved hydrogenperoxid i dette tilfælde anvendes som reagens,kunne nul-potentialets forskydning ved kon-30 tinuerlig drift kompenseres, og målingen af cyanidion-koncentrationen gennemføres upåklageligt ved den kontinuerte spildevandsafgiftning.By using the process of the invention, whereby hydrogen peroxide is used as a reagent in this case, the zero potential displacement in continuous operation could be compensated and the measurement of the cyanide ion concentration carried out impeccably by the continuous wastewater detoxification.
Der optrådte ingen påvirkning af redox-potentia-let fra selve hydrogenperoxidet såvel som det fremkomne 35 cyanat.There was no effect on the redox potential from the hydrogen peroxide itself as well as the resulting cyanate.
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Herved gås der frem således, at den sidestrøm af spildevandet, der skal undersøges føres gennem en reaktionsstrækning uden tilsætning af reagens - her hydro-genperoxid - hvorved målekædens tilsvarende potential 5 fastlægges, hvorefter reagenset efter et vist tidsinterval tilsættes kontinuert i reaktionsstrækningen under et andet tidsinterval, hvorved målekædens nul-potentiale, der indstiller sig, måles. Derefter afbrydes hydrogen-peroxidtilsætningen.Hereby it is stated that the lateral flow of the wastewater to be examined is passed through a reaction section without the addition of reagent - here hydrogen peroxide - whereby the corresponding potential of the measuring chain 5 is determined, and after a certain time interval the reagent is continuously added in the reaction section for another time interval. , whereby the zero potential of the tuning chain that is tuned is measured. Then the hydrogen peroxide addition is interrupted.
10 Derefter genindstiller den øjeblikkelige kon centration af den iontype, der skal måles - her cyanidioner - sig automatisk, hvorefter cyklusen med tilsætning af reagens - her hydrogenperoxid - atter begyn der.10 Then the instantaneous concentration of the ion type to be measured - here cyanide ions - resets itself automatically, after which the cycle of reagent addition - here hydrogen peroxide - begins again.
15 Reagenset kan anvendes i den til omsætningen støkiometriske mængde men dog fortrinsvis i overskud.The reagent may be used in the stoichiometric amount of the reaction, but preferably in excess.
Ved beregningen af den støkiometriske mængde reagens skal den maksimale forventede mængde af den iontype, der skal måles, fortrinsvis lægges til grund.When calculating the stoichiometric amount of reagent, the maximum expected amount of the ion type to be measured should preferably be used.
20 Ved uventet optrædende koncentrationssvingninger i opløsningen, der skal måles, kan der således ikke optræde fejlagtige resultater.Thus, in the event of unexpected concentration fluctuations in the solution to be measured, erroneous results may not occur.
Denne mængde lader sig let fastlægge ved et kontrolforsøg.This quantity can easily be determined by a control experiment.
25 Den omhandlede fremgangsmåde er for så vidt temperaturuafhængig, som der til dens gennemførelse ikke er noget bestemt temperaturområde nødvendigt, men måletemperaturen retter sig efter de pågældende reaktioner. Blot forløber omsætningen i almindelighed 30 hurtigere ved højere tempreatur. Målekædens elektromotoriske kraft er temperaturuafhængig og kan - som kendt ved redox- og ionfølsomme elektroder - kompenseres, f.eks. automatisk over et modstandstermometer.25 The process in question is temperature independent in that no specific temperature range is necessary for its implementation, but the target temperature is based on the reactions in question. Generally, the reaction generally proceeds 30 faster at higher temp. The electromotive force of the measuring chain is temperature independent and - as known by redox and ion sensitive electrodes - can be compensated, e.g. automatically over a resistance thermometer.
Tidsintervallet mellem måling af nul-potentialet 35 0g cyanidionkoncentrationen, der efter nogen tid atter har indstillet sig, kan af kontroltekniske grunde fortrinsvis altid være den samme. Fremgangsmådens succes iThe time interval between measurement of the zero potential 35g and the cyanide ion concentration, which after some time has re-set, may preferably always be the same for control reasons. Success of the process i
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6 sig selv begrænses dog ikke véd uregelmæssige tidsintervaller mellem de forskellige koncentrationsmålinger. De passende tidsintervaller fastlægges med et forforsøg, de kan f.eks. være 1 til 2 minutter.6 itself, however, is not limited by irregular time intervals between the different concentration measurements. The appropriate time intervals are determined with a preliminary experiment. be 1 to 2 minutes.
5 Fordelen ved anvendelse af regelmæssige tids intervaller ligger i muligheden af at indkoble en taktgiver .5 The advantage of using regular time intervals lies in the possibility of switching on a clock sensor.
Tidsrummets længde mellem fastlæggelse af den øjeblikkelige koncentration og tilsætning af hydrogen-10 peroxid i overskud skal holdes så lille som muligt eftersom også reaktionen mellem hydrogenperoxid og de foreliggende cyanidioner kræver en vis tid.The length of time between the determination of the instantaneous concentration and the addition of hydrogen peroxide in excess must be kept as small as possible since the reaction between hydrogen peroxide and the present cyanide ions also requires some time.
Indsættes en taktgiver, er tidsintervallerne til måling af komponentens øjeblikkelige koncentration og 15 nul-potentialet he] t lige store.If a clock sensor is inserted, the time intervals for measuring the instantaneous concentration of the component and the 15 zero potential are quite large.
Opfindelsen beskrives nærmere under henvisning til tegningen, hvor fig. 1 v^ser tidsforløbet af målekædespændingen; fig. 2 en indretning til en kontinuert udøvelse 20 af opfindelsen; fig. 3 en indretning til en diskontinuert udøvelse af opfindelsen; og fig. 4 en logaritmisk afbildning af potentialspring versus cyanidionkoncentration.The invention is described in more detail with reference to the drawing, in which fig. 1 shows the time course of the measuring chain tension; FIG. 2 shows a device for continuous practice 20 of the invention; FIG. 3 shows a device for a discontinuous practice of the invention; and FIG. 4 is a logarithmic representation of potential jump versus cyanide ion concentration.
25 På tegningen viser fig. 1 det tidslige forløb af målekædespændingen med lige store tidsintervaller til måling af komponentkoncentrationen - i dette tilfælde cyanidionen - og til måling af nulpotentialet -i dette tilfælde ved hydrogenperoxid-tilsætning.25 In the drawing, FIG. 1 shows the temporal course of the measurement chain voltage at equal time intervals for measuring the component concentration - in this case the cyanide ion - and for measuring the zero potential - in this case by hydrogen peroxide addition.
30 På abscissen vises målekædens potential og på ordinaten tiden. De tidsintervaller, hvorved hydrogenperoxid- tilsætningen foregår er indtegnet som bjælker 2.30 On the abscissa the potential of the measuring chain is shown and on the ordinate the time. The time intervals at which the hydrogen peroxide addition takes place are plotted as beams 2.
Der begyndes i dette tilfælde med indstilling af nulpotentialet, dvs. med tilsætningen af et overskud af 35 hydrogenperoxid i forhold til de tilstedeværende cyanidioners ækvivalente mængde.In this case, the zero potential is started, ie. with the addition of an excess of hydrogen peroxide relative to the equivalent amount of cyanide ions present.
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Tidsintervallerne blev målt i minutter.The time intervals were measured in minutes.
Som det ses af fig. 1 går målekædens potential hver gang tilbage til det indstillede nul-punkt, såsnart systemet tilføres . . den tilsvarende mængde hy-5 drogenperoxid.As seen in FIG. 1, the potential of the measuring chain goes back to the set zero point each time the system is applied. . the corresponding amount of hydrogen peroxide.
Potentialforskellen til måletidspunkterne 3 og 4 gælder som mål for cyanidionkoncentrationen.The potential difference for the measurement times 3 and 4 applies as a measure of the cyanide ion concentration.
Det bemærkes her endnu engang, at målekædens potential i praksis ikke påvirkes af det overskydende 10 hydrogenperoxid, dette blev fastslået inden målingens gennemførelse.It is noted here again that in practice the potential of the measuring chain is not affected by the excess hydrogen peroxide, which was determined before the measurement was carried out.
Koncentrationen af det reagens, der skal anvendes - det anvendes . i almindelighed i vandig opløsning -afhænger af koncentrationen af den iontype, der skal må-15 les.The concentration of the reagent to be used - it is used. generally in aqueous solution - depends on the concentration of the ion type to be measured.
Er denne koncentration høj, kan der anvendes mere koncentrerede reag.ensopløsninger. Er denne koncentration lavere, foretrækkes mindre koncentrerede opløsninger til indikering af slutproduktet.If this concentration is high, more concentrated reagent solutions can be used. If this concentration is lower, less concentrated solutions are indicated for indicating the final product.
20 Den omhandlede fremgangsmåde kan gennemføres så vel kontinuert som diskontinuert.The present process can be carried out both continuously and discontinuously.
Dette er ligeledes belyst ved eksemplet med cyanidafgiftning fra spildevand med hydrogenperoxid.This is also illustrated by the example of cyanide detoxification from wastewater with hydrogen peroxide.
Den i fig. 2 viste indretning arbejder på følgen-25 de måde:The FIG. 2 shows the following operation:
En mindre delstrøm af det cyanidionholdige spildevand, der skal undersøges, flyder over ledning 1 og la gennem en reaktionsstrækning 2. Ved afslutningen af reaktionsstrækningen 2 måles redox-potentialet med 30 f*eks.'en sølv/thalamidelektrode ved 3. Ved reaktionsstrækningens begyndelse dvs. ved indføringen af ledning 5a i ledning la tilsættes ved lb alternerende fortyndet hydrogenperoxidopløsning fra en beholder 5 over ledning 5a og over en ventil 4, der styres med 35 et tidsur, og dermed måles det potential , der svarer til cyanidionkoncentrationen 0. Udfra forskellen mellem de to målinger opnås den øjeblikkeligt foreliggende cyanidionkoncentration.A minor subcurrent of the cyanide ion-containing wastewater to be examined flows over line 1 and 1a through a reaction line 2. At the end of the reaction line 2, the redox potential is measured by 30 f * e.g. the silver / thalamide electrode at 3. At the beginning of the reaction line, i.e. . by introducing line 5a into line 1a, alternating diluted hydrogen peroxide solution from a container 5 is added over line 5a and over a valve 4 controlled by 35 for a time, thus measuring the potential corresponding to the cyanide ion concentration 0. From the difference between the two measurements obtain the instant cyanide ion concentration present.
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Den anden måling,dvs. nul-potentialet,gennemføres med den samme elektrode ved 3. Spildevandet fjernes kontinuert over ledning 6 og kastes i dette særlige tilfælde bort.The second measurement, ie. zero potential, is conducted with the same electrode at 3. The waste water is continuously removed over line 6 and in this particular case is discarded.
5 Derimod foretrækkes det ved gennemføring af ke miske processer,at den målte delstrøm atter føres tilbage i hovedstrømmen.On the other hand, in carrying out chemical processes, it is preferred that the measured subcurrent be returned to the main stream.
Systemet afluftes over ledning lc.The system is vented over line lc.
Medens måleresultaterne ved den kontinuerte gen-10 nemførelse af den omhandlede fremgangsmåde er upåklagelige, er der i visse tilfælde i praksis opstået tekniske vanskeligheder ved gennemførelsen af målingerne f.eks. ved forsinkelse i reaktionstrækningenjjvf. eksempel 1.While the measurement results of the continuous implementation of the method in question are impeccable, in some cases in practice technical difficulties have arisen in the performance of the measurements, e.g. by delay in the reaction drawjjf. Example 1.
Herved kan en effektiv gennemblanding af opløsningen, 15 der skal undersøges og det tilførte reagens ikke aktid sikres.In this way, an effective mixing of the solution to be investigated and the reagent added can not be ensured on time.
Af denne grund foretrækkes den diskontinuerte gennemførelse a^ den omhandlede fremgangsmåde.For this reason, the discontinuous implementation of the method in question is preferred.
Denne fungerer- som følger: 20 I forhold til den kontinuerte metode foretages målingen ikke i en beholder, der kontinuert gennemstrømmes af den opløsning, der skal måles, men - se fig. 3 - i en reaktionsbeholder 3 med omrører 4.This works as follows: 20 Compared to the continuous method, the measurement is not carried out in a container that is continuously flowing through the solution to be measured, but - see fig. 3 - in a reaction vessel 3 with stirrer 4.
Denne reaktionsbeholder er kombineret med to måleglas, 25 2 og 8, hvoraf det ene 2 er beregnet til opløsning-gen, der skal undersøges, og det andet 8 til reagenset, der skal tilsættes.This reaction vessel is combined with two measuring vials, 2 2 and 8, one 2 for the solution gene to be tested and the other 8 for the reagent to be added.
I reaktionsbeholderen 3 tildoseres i et første tidsskridt en afmålt mængde af den pågældende opløsning 30 fra et måleglas 2 der er begrænset ved ventiler 2a og 2b (ventilerne 2a og 2b er af eksplosionssikkerhedsgrunde fortrinsvis trykluftstyrede).In the reaction vessel 3, in a first time step, a metered amount of the relevant solution 30 is dispensed from a measuring glass 2 limited by valves 2a and 2b (valves 2a and 2b are preferably air-controlled for explosion safety reasons).
Ved punkt 5 befinder sig en elektrode^der måler den øjeblikkelige ionkoncentration, f.eks. cyanidion-35 koncentrationen. Elektroden ved punkt 5 skal fortrinsvis være i stand til at fastslå denne koncentration umiddelbart efter tilsætning af opløsningen fra måleglasset 2.At point 5, there is an electrode measuring the instantaneous ion concentration, e.g. cyanide ion concentration. The electrode at point 5 should preferably be capable of detecting this concentration immediately after adding the solution from the measuring tube 2.
DK 154458 BDK 154458 B
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Fra en forrådsbeholder 6 føres reagenset - i tilfældet med .cyanidionmålingen, altså hydrogenperoxid -over ledning 7 ind i et måleglas 8 til reagenset. Måleglasset 8 er som måleglas 2 forsynet med tilsvarende 5 ventiler 8a og 8b, der ligeledes fortrinsvis er tryklufts tyrede.From a reservoir 6, the reagent - in the case of the cyanide ion measurement, i.e. hydrogen peroxide - is passed over conduit 7 into a measuring glass 8 to the reagent. The measuring tube 8 is provided, like the measuring tube 2, with the corresponding 5 valves 8a and 8b, which are also preferably compressed air driven.
I det tidsskridt, der følger efter målingen af ionkoncentrationen,tilsættes hydrogenperoxid i beholderen 3, reaktionen afventes i et vis.t tidsrum, og derpå 10 måles det nu fremkomne nul-potential med elektroden ved 5.In the time step following the measurement of the ion concentration, hydrogen peroxide is added to the container 3, the reaction is awaited for a certain period of time, and then the zero potential obtained with the electrode is measured at 5.
Derefter åbnes en ventil 9, og beholderen 3 tømmes. Sekvensen gentages tilsvarende.A valve 9 is then opened and the container 3 emptied. The sequence is repeated accordingly.
Ventilerne 2a og 2b samt 8 a og 8b styres 15 således, at der sikres et gnidningsløst forløb af den ovenfor beskrevne metode.Valves 2a and 2b as well as 8a and 8b are controlled 15 to ensure a smooth operation of the method described above.
Den diskontinuerte gennemførelse af den omhand-led , fremgangsmåde udmærker sig ved, at de ovenfor næ\ ,i-te ulemper ved den kontinuerte gennemførelse hér undgås, 20 og at den diskontinuerte gennemførelse også arbejder tilfredsstillende ved tekniske anlæg.The discontinuous implementation of the present method is distinguished by the fact that the above mentioned disadvantages of continuous implementation are avoided here, and that the discontinuous implementation also works satisfactorily in technical installations.
Også tiden, der kræves til målingen, lader sig ved d'in diskontinuerte gennemførelse nedsætte i forhold til den kontinuerte måling, således udgør f.eks. tiden 25 til en målecyklus ved bestemmelsen af cyanidioner med hydrogenperoxid ca. 2-3 minutter i forhold til 10 minutter ved den kontinuerte gennemførelse. Grunden hertil ligger i den spontane reaktion af f.eks. cyanidionerne med hydrogenperoxid i reaktionsbeholderen,, der - som 30 nævnt - er udstyret med en omrører, således at der foregår en umiddelbar blanding af reaktanterne. Selv på trods af det yderligere trin med tømning ved den diskontinuerte gennemførelse, opnås der da i forhold til den kontinuerte gennemførelse en tidsgevinst.Also, the time required for the measurement can be reduced by the continuous measurement in relation to the continuous measurement. the time 25 to a measurement cycle in the determination of cyanide ions with hydrogen peroxide approx. 2-3 minutes versus 10 minutes of continuous execution. The reason for this lies in the spontaneous reaction of e.g. the cyanide ions with hydrogen peroxide in the reaction vessel, which - as mentioned - are equipped with an agitator so that an immediate mixing of the reactants takes place. Even in spite of the additional step of emptying the discontinuous implementation, a time gain is achieved compared to the continuous implementation.
35 Yderligere er det således, at apparaturet som sådanfi er væsentligt mere simpelt og sikkert overfor afbrydelser, eftersom der ikke blandes væskestrømme men rumfang, og derfor ikke kræves nogen strømningsmåler.Further, it is thus that the apparatus as such is substantially simpler and more secure against interruptions, since no fluid flow but volume are mixed and therefore no flow meter is required.
»»
DK 154458 BDK 154458 B
1010
Fremgangsmåden ifølge opfindelsen er også anvendelig til potentiostatiske indretninger.The method of the invention is also applicable to potentiostatic devices.
Opfindelsen belyses nærmere med de følgende eksempler: 5The invention is further illustrated by the following examples:
Eksempel 1.Example 1.
Kontinuer lig fremgangsmåde.Continuous procedure.
Som en væskedelstrøm, der skal undersøges, anvendes en opløsning med en CN -koncentration på 12 mg/ 10 liter og en katalysatorandel (angivet i DE-PS 2.352.856) på 0,02 rumfangsprocent. Opløsningen har en temperatur på 95°C og en pH-værdi på 11,5.As a liquid boiler stream to be investigated, a solution having a CN concentration of 12 mg / 10 liters and a catalyst fraction (specified in DE-PS 2,352,856) of 0.02 vol% is used. The solution has a temperature of 95 ° C and a pH of 11.5.
En strøm på ca. 100 liter/time af udgangsopløsningen føres under henvisning til fig. 2 gennem lednin-15 gen la og lb ind i reaktionsstrækningen 2. Efter reaktionsstrækningen måles udgangsopløsningens redox-potential i det første trin med elektroden 3. Til det efterfølgende andet trin åbnes ventilen 4 i et tidsrum på ca. 5 minutter, og der strømmer 0,5 liter 20 pr. tidstrin 3,5 vægt%'ig H202-opløsning ud af beholderen 5 over ledningen 5a og 5b ind i reaktionsstrækningen 2. Den fra nedbrydningen af frigjorte oxygen udsluses gennem afluftningsledningen lc fra måleapparaturet. Under det andet trin måles det ændrede 25 redoxpotential, der som følge af den fuldstændige omdannelse af cyanidet til cyanat svarer til CN -nulkoncentrationen. Udfra målingen af de to redoxpotentialer opnås en potentialforskel på 336 .mV for udgangs-opløsningen. På grund af den trinstyrede ventil 4, der 30 tager hensyn til forsinkelsen på reaktionsstrækningen kræver målegangen en tid på ca. 10 minutter.A current of approx. 100 liters / hour of the starting solution are carried out with reference to FIG. 2 through lines 1a and 1b into the reaction section 2. After the reaction section, the redox potential of the starting solution is measured in the first stage with the electrode 3. For the subsequent second stage, the valve 4 is opened for a period of approx. 5 minutes and 0.5 liters of flow per minute. time step 3.5 wt% of H2 O2 solution out of the container 5 over line 5a and 5b into the reaction line 2. The oxygen released from the decomposition of oxygen is drained through the vent line 1c from the measuring apparatus. In the second step, the altered redox potential is measured, which, as a result of the complete conversion of the cyanide to cyanate, corresponds to the CN-zero concentration. From the measurement of the two redox potentials, a potential difference of 336 .mV is obtained for the starting solution. Due to the step-controlled valve 4, which takes into account the delay in the reaction stretch, the measuring time requires a time of approx. 10 minutes.
Eksempel 2.Example 2.
Diskontinuerlig fremgangsmåde.Discontinuous procedure.
35 I fig. 3 vises det diskontinuerte forsøgsapparatur med de trinstyrede ventiler.35 In FIG. 3 shows the discontinued test apparatus with the step-controlled valves.
Som en væskedelstrøm, der skal undersøges, anvendes en opløsning med CN -koncentration på 120 mg/litetAs a liquid boiler stream to be investigated, a solution with CN concentration of 120 mg / l is used
DK 154458 BDK 154458 B
11 og en katalysatorandel (angivet i DE-PS 2.352.856) på 0,02 rumgangsprocent. Opløsningen har en temperatur på 90°C og en pH-værdi på 11,3.11 and a catalyst fraction (specified in DE-PS 2,352,856) of 0.02 volume percent. The solution has a temperature of 90 ° C and a pH of 11.3.
Med lukket ventil 2a og forsinket åbnet ventil 5 2b fyldes det 1000 ml store målerumfang 2 med opløsningen. Efter afspærring af ventilen 2b og forsinket åbning af 2a strømmer opløsningsmængden ved det første trin ind i tørebehoIderen 3. .Med elektroden 5 måles redoxpotentialet af udgangsmængden. Fra det i 10 mellemtiden fra beholderen 6 over ledningen 7 fyldte målerumfang 8 på 30 ml, foregår tilsætningen af en 3,5 vægt%'ig H^O^-opløsning ved åbning af ventilen 8b og forsinket åbning af 8a. Omrøreren 4 sørger i det andet trin for en god gennemblanding af de to væsker.With closed valve 2a and delayed opened valve 5 2b, 1000 ml large measuring volume 2 is filled with the solution. After shut-off of valve 2b and delayed opening of 2a, the amount of solution at the first stage flows into the dryer container 3. With the electrode 5, the redox potential is measured by the output amount. From the measuring volume 8 of 30 ml filled from the container 6 over the conduit 7 by 30 ml, the addition of a 3.5 wt.% H 2 O 2 solution takes place at the opening of the valve 8b and delayed opening of 8a. In the second step, the agitator 4 provides a good mixing of the two liquids.
15 Det i overskud,! forhold til den støkiometriske mængde, tilstedeværende H202 omsætter den tilstedeværende cyanidmængde. fuldstæfldigt til cyanat, og der måles et re-doxp^tential, der svarer til CN -nulkoncentrationen.15 That in excess,! relative to the stoichiometric amount of H 2 O 2, the amount of cyanide present is converted. fully to cyanate, and a re-doxpential corresponding to the CN-zero concentration is measured.
For udgangsopløshingen opnås en potentialforskel på 20 458 mV. Efter målingen tømmes beholderen 3 i det tredie trin. Måleforløbet kræver en tid på ca. 2,5 minutter. Til trykudligning afluftes beholderne 3 og 6 over ledningerne henholdsvis 10 og 11.For the output resolution a potential difference of 20,458 mV is obtained. After the measurement, the container 3 is emptied in the third step. The measurement process requires a time of approx. 2.5 minutes. For pressure equalization, the containers 3 and 6 are vented over the lines 10 and 11 respectively.
25 Eksempel 3.Example 3.
Den omhandlede fremgangsmåde blev afprøvet i forskellige forsøgsserier med spildevand med forskellig CN -koncentration. Den ikke afgiftede udgangsopløsning havde en CN -koncentration på 120 mg/liter. Denne op-30 løsning blev trinvist fortyndet til 1,2 mg/liter og potentialet blev registreret. Derudover blev der i laboratoriet fremstillet opløsninger med cyanidkoncentrationer på 1 mg/liter, .0,1 mg/liter og 0,01 mg/liter. pH-værdien blev derefter indstillet til 12, den ifølge DE-PS 35 23 52 856 foreskrevne mængde aktivator af -0,02 rumfangsprocent blev tilsat opløsningen. Fig. 4 viser sammenhængen mellem potentialspring og CN -koncentration i området fra 0,01 til 100 mg/liter. Ved denne simple loga-The method in question was tested in different series of wastewater experiments with different CN concentrations. The non-detoxified starting solution had a CN concentration of 120 mg / liter. This solution was gradually diluted to 1.2 mg / liter and the potential was recorded. In addition, solutions with cyanide concentrations of 1 mg / liter, 0.1 mg / liter and 0.01 mg / liter were prepared in the laboratory. The pH was then adjusted to 12, the amount of activator of -0.02 volume percent prescribed according to DE-PS 35 23 52 856 was added to the solution. FIG. Figure 4 shows the relationship between potential jump and CN concentration in the range of 0.01 to 100 mg / liter. By this simple loga-
Claims (9)
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE2917714 | 1979-05-02 | ||
| DE2917714A DE2917714C2 (en) | 1979-05-02 | 1979-05-02 | Procedure for measuring with redox or ion-sensitive electrodes |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| DK179980A DK179980A (en) | 1980-11-03 |
| DK154458B true DK154458B (en) | 1988-11-14 |
| DK154458C DK154458C (en) | 1989-04-10 |
Family
ID=6069774
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| DK179980A DK154458C (en) | 1979-05-02 | 1980-04-25 | METHOD OF PAINTING WITH REDOX OR ION SENSITIVE ELECTRODES |
Country Status (12)
| Country | Link |
|---|---|
| JP (1) | JPS55151255A (en) |
| AT (1) | AT381395B (en) |
| BE (1) | BE883046A (en) |
| CA (1) | CA1132660A (en) |
| CH (1) | CH645990A5 (en) |
| DE (1) | DE2917714C2 (en) |
| DK (1) | DK154458C (en) |
| FR (1) | FR2455740A1 (en) |
| GB (1) | GB2049951B (en) |
| IT (1) | IT1128438B (en) |
| NL (1) | NL8001823A (en) |
| SE (1) | SE8003310L (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL8303792A (en) * | 1983-11-03 | 1985-06-03 | Cordis Europ | Apparatus provided with an measuring circuit based on an ISFET; ISFET SUITABLE FOR USE IN THE MEASURING CIRCUIT AND METHOD FOR MANUFACTURING AN ISFET TO BE USED IN THE MEASURING CIRCUIT |
| SE9000166L (en) * | 1990-01-17 | 1991-07-18 | Eka Nobel Ab | redox |
| JP5116068B2 (en) * | 2004-09-07 | 2013-01-09 | Ｊｘ日鉱日石金属株式会社 | Method for stabilizing electroless gold plating solution |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2018514A1 (en) * | 1970-04-17 | 1971-11-04 | Schierjott G | Continuous flow analyser |
| DE2352856A1 (en) * | 1973-10-22 | 1975-04-30 | Degussa | PROCESS FOR DETOXIFICATION OF CYANIDES AND NITRILE WITH PERSONAL OXYGEN COMPOUNDS |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2773019A (en) * | 1954-07-26 | 1956-12-04 | Exxon Research Engineering Co | Control of hypochlorite treating operation |
| NL292885A (en) * | 1963-05-16 | |||
| DE1523018A1 (en) * | 1964-10-08 | 1969-04-24 | Siemens Ag | Measuring device for the automatic measurement of the cyanide content and / or the pH value of industrial waste water |
| DE2043176A1 (en) * | 1969-11-12 | 1971-05-27 | Zellweger Uster Ag | Slide rule to evaluate non meter readings - for concentration measurements |
| US4002428A (en) * | 1976-05-21 | 1977-01-11 | The United States Of America As Represented By The Secretary Of The Interior | Deductive method for measuring ion concentration electrically |
| US4049382A (en) * | 1977-02-16 | 1977-09-20 | Orion Research Incorporated | Total residual chlorine |
-
1979
- 1979-05-02 DE DE2917714A patent/DE2917714C2/en not_active Expired
-
1980
- 1980-03-27 NL NL8001823A patent/NL8001823A/en not_active Application Discontinuation
- 1980-04-17 FR FR8008655A patent/FR2455740A1/en active Granted
- 1980-04-25 DK DK179980A patent/DK154458C/en not_active IP Right Cessation
- 1980-04-29 BE BE6/47152A patent/BE883046A/en not_active IP Right Cessation
- 1980-04-30 AT AT0231980A patent/AT381395B/en not_active IP Right Cessation
- 1980-04-30 SE SE8003310A patent/SE8003310L/en not_active Application Discontinuation
- 1980-04-30 IT IT67687/80A patent/IT1128438B/en active
- 1980-05-01 CA CA351,040A patent/CA1132660A/en not_active Expired
- 1980-05-01 CH CH338380A patent/CH645990A5/en not_active IP Right Cessation
- 1980-05-02 GB GB8014859A patent/GB2049951B/en not_active Expired
- 1980-05-02 JP JP5803180A patent/JPS55151255A/en active Granted
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2018514A1 (en) * | 1970-04-17 | 1971-11-04 | Schierjott G | Continuous flow analyser |
| DE2352856A1 (en) * | 1973-10-22 | 1975-04-30 | Degussa | PROCESS FOR DETOXIFICATION OF CYANIDES AND NITRILE WITH PERSONAL OXYGEN COMPOUNDS |
Also Published As
| Publication number | Publication date |
|---|---|
| IT8067687A0 (en) | 1980-04-30 |
| SE8003310L (en) | 1980-11-03 |
| CA1132660A (en) | 1982-09-28 |
| BE883046A (en) | 1980-10-29 |
| DK179980A (en) | 1980-11-03 |
| JPS55151255A (en) | 1980-11-25 |
| GB2049951A (en) | 1980-12-31 |
| DK154458C (en) | 1989-04-10 |
| IT1128438B (en) | 1986-05-28 |
| FR2455740B1 (en) | 1983-12-09 |
| ATA231980A (en) | 1986-02-15 |
| NL8001823A (en) | 1980-11-04 |
| GB2049951B (en) | 1983-05-25 |
| CH645990A5 (en) | 1984-10-31 |
| FR2455740A1 (en) | 1980-11-28 |
| JPS6329218B2 (en) | 1988-06-13 |
| DE2917714A1 (en) | 1981-03-26 |
| DE2917714C2 (en) | 1983-12-22 |
| AT381395B (en) | 1986-10-10 |
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