EP0077041A1 - Method for the replenishment of cleaning solutions - Google Patents

Method for the replenishment of cleaning solutions Download PDF

Info

Publication number
EP0077041A1
EP0077041A1 EP82109310A EP82109310A EP0077041A1 EP 0077041 A1 EP0077041 A1 EP 0077041A1 EP 82109310 A EP82109310 A EP 82109310A EP 82109310 A EP82109310 A EP 82109310A EP 0077041 A1 EP0077041 A1 EP 0077041A1
Authority
EP
European Patent Office
Prior art keywords
acid
temperature
solution
fluoride ion
fluoride
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Withdrawn
Application number
EP82109310A
Other languages
German (de)
French (fr)
Inventor
Richard Andrew Beck
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
GEA Group AG
Continentale Parker Ste
Continentale Parker SA
Original Assignee
Metallgesellschaft AG
Continentale Parker Ste
Continentale Parker SA
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Metallgesellschaft AG, Continentale Parker Ste, Continentale Parker SA filed Critical Metallgesellschaft AG
Publication of EP0077041A1 publication Critical patent/EP0077041A1/en
Withdrawn legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
    • C23G1/12—Light metals
    • C23G1/125—Light metals aluminium

Definitions

  • the invention relates to a method for supplementing cleaning solutions in the cleaning of aluminum surfaces with acidic aqueous solutions containing fluoride ions, in which the fluoride ion content is measured and supplemented with fluoride ions and acid.
  • Aluminum objects e.g. Aluminum cans can be cleaned by contact with an aqueous solution containing fluoride ions.
  • aqueous solution containing fluoride ions contain e.g. Fluoride ions and sulfuric acid (GB-PS 1 454 974).
  • control methods are carried out by keeping the temperature of the treatment bath at a constant value by means of suitable heating and / or cooling systems, and both the fluoride ion content and the acid content by measuring the content of free fluoride ions or the pH value and supplementing it with fluoride and acid, depending on the deviation from the respective setpoint.
  • the known methods have the disadvantage in common that a precise indication of the amounts of chemicals to be added requires a constant temperature of the treatment bath, a requirement which is usually not given.
  • the conventional metering of the supplementary chemicals to a target value based on a measured actual value often leads to an overdose of the chemicals to be supplemented, since the concentration balance between the supplemental solution and the treatment solution supplied in practice is often of the order of several minutes.
  • the object of the invention is to provide a method for supplementing cleaning solutions which avoids the disadvantages of the known methods, is simple to carry out and does not require a high outlay on equipment Lich.
  • the object is achieved by designing the method of the type mentioned at the outset in accordance with the invention in such a way that the metering of the quantity of chemicals is regulated as a function of the deviation from the automatically corrected setpoint of the fluoride ion concentration and required for constant pickling removal.
  • the inventive method comprises device parts for measuring the F luoridionengehaltes, parts of the device for measuring the temperature of the detergent solution as well as correction elements (override Means) on to the value in terms of fluoride ion content as a function of or compensate for change in the detected temperature - in each case based on a predetermined Temperature value - to change.
  • the device parts for measuring the fluoride ion content of the cleaning solution are expediently connected to a device for generating a signal in the event of a deviation from the predetermined value.
  • An optical display for example in the form of a pointer instrument, is suitable for this.
  • the device parts for measuring the temperature and - if necessary. Deviations from the target value that occur - for adaptation contains elements for applying a signal to the display instrument. The result of this is that a fluoride ion content is displayed which, depending on the type of temperature deviation, is higher or lower than the actual fluoride ion content.
  • the temperature-corrected value obtained in this way ultimately controls the dosage of the supplementary solution and ensures constant removal of the pickling.
  • the fluoride ion content shown on the display device would be about twice as high as the value actually present in the cleaning solution. In practical terms, this means that when the temperature of the cleaning solution rises by 10 ° C, the fluoride ion content actually measured is reduced to about half as a result of the regulation. If the temperature drops by 10 ° C below the target temperature, a correspondingly reduced content of fluoride ions would be indicated, but this is increased accordingly by the control.
  • the amount of acid required to supplement the cleaning solution can be determined as a function of a separate acid measurement, for example by means of a conductivity or pH measurement.
  • the acid is added without a separate acid measurement, but in conjunction with the fluoride ion addition by means of a metering device, which is also controlled by measuring the fluoride ion content of the cleaning solution.
  • a certain relationship between fluoride ion supplementation and acid supplementation is determined and set on the basis of empirical values or by preliminary tests.
  • the Dösiervoriques can be used for the fluoride ion-containing solution at a certain flow rate during a time-b deviation from the A of the measured fluoride ion content from the desired value is dependent, and are operated at the same time a Do Siervoriques for acid for a period of time, which is in a predetermined relation to the running time of the metering device for fluorine dosing, in motion.
  • a coupled acid supplement which is controlled solely by the fluoride ion content of the cleaning solution, is associated under normal operating conditions with deviations in the acid supplement of at most 5%.
  • the control device provides a safety circuit which ensures the addition of acid at predetermined time intervals, even if no fluoride ions are added. This means that if sufficient acid is added as a result of the usual addition, the safety circuit does not operate.
  • the safety circuit starts the metering for acid from time to time so long that the acid content is at an appropriate level.
  • the time after which the safety circuit is activated can be determined in a very simple manner by experiments. It generally depends on the normal loss of detergent solution, the free acidity of the detergent solution, the concentration of the make-up solution for acid and the metering capacity of the metering device for the acid.
  • fluoride ions are also optionally coupled therewith acid at a predetermined delivery rate of the metering devices in A b-dependence of the determined metered fluoride ion content of the cleaning solution for a certain period.
  • a metering device for the solution containing fluoride ions, a metering device for the acid and a device for measuring the fluoride ion content of the cleaning solution are also provided here.
  • the electronic circuit used in the method according to the invention has a variable circuit which gives a pulse duty factor (mark / space ratio) and is connected to a clock generator.
  • the time interval at which the metering devices are started can be selected by the clock generator.
  • the measuring device is expediently installed at a point at which the cleaning solution which is directly in use is obtained. That is, in the preferred cleaning by spraying, the measuring device is advantageously connected to the pipelines connected to the circulation pumps.
  • the running time of the cyclically switched metering devices is expediently chosen such that they meter about half the time of a cycle interval during normal operation of the cleaning system. With a cycle time of 4 minutes, their running time would be about 2 minutes.
  • the delivery rate of the dosing devices must be adapted to the need for a supplementary solution.
  • control device can be connected to an additional device which prevents the metering devices from being controlled as a result of operational malfunctions with an unusually short or long runtime within a supplementary cycle.
  • This abnormal operating condition can. are indicated by warning indicators.
  • the use of such power keys has the disadvantage that they can lead to incorrect displays as a result of loss of electrolyte solution. This can be remedied if the power key has a container for the electro-hydroxide solution, which is connected to an additional warning electrode. It is coupled to the reference electrode and arranged in the electrolyte solution container in such a way that it emits a warning signal as soon as the level of the electrolyte drops below a certain level.
  • Such a current key accordingly has a container for the electrolyte and reference or warning electrodes immersed in the electrolyte.
  • the lowest part of the warning electrode is in a position above that at which the reference electrode becomes ineffective. Under normal operating conditions there is electrical contact between the warning and reference electrodes. If the electrolyte level in the container drops below a certain level, the warning electrode no longer dips into the electrolyte. The thus changing potential difference between the reference and warning electrodes triggers a warning signal which can be implemented in any way, for example acoustically or optically.
  • the electrolyte used in the power key is usually an aqueous potassium chloride solution.
  • the warning electrode can e.g. consist of a stainless steel rod.
  • a calomel electrode is usually used as the reference electrode.
  • An electrode 1 responsive to fluoride ions is immersed in a treatment bath 2 and connected to a reference electrode 3 (calomel electrode) by a conventional circuit 4.
  • the reference electrode 3 is immersed in an aqueous potassium chloride electrolyl solution, which is located in a container 6.
  • a tube 7 ends in a ceramic porous stopper 8, which in turn is immersed in the treatment bath 2.
  • a rod-shaped warning electrode 9 made of stainless steel is fixed in the electrolyte solution 5 in such a way that its lower end ends above the level of the upper edge of the reference electrode 3.
  • An electrical connection between reference electrode 3 and warning electrode 9 is indicated by device parts 10. These include a suitable warning device which operates when the potential difference between the electrodes 3 and 9 is undesirably exceeded.
  • the cleaning solution usually has a temperature of 30 to 70 ° C, a pH below 3, usually between 1 and 2.5, in particular 1.5, and a free fluoride ion content of 0.05 to 10, preferably 0.1 up to 5 and in particular from 0.8 mg / l.
  • a cleaning solution can be easily done with hydrofluoric acid or other fluoride ion-providing substances and sulfuric acid, if necessary with the additional use of surfactant. It is used for the usual spray cleaning of, for example, aluminum cans.
  • the fluoride ion content and the temperature are continuously monitored.
  • the temperature is shown as a digital display, the temperature-corrected fluoride ion content is shown by an indicator, as explained above.
  • a supplementary operation is started every 4 minutes by means of a clock and a mark / space ratio circuit, whereby, in order to keep the fluoride ion content constant, a pump for supplying fluoride-containing supplementary solution in a predetermined manner for a time dependent on the position depends on the display device, is activated. At the same time, a second pump adds sulfuric acid during a time that is in a predetermined ratio to the addition period of the fluoride ion addition.

Abstract

The free fluoride content of the aqueous acidic solution is recorded e.g. by an electrode 2 and a signal is generated, in response to the deviation of the actual value from a predetermined value, and this signal is utilised for controlling a pump 14 for supplying replenishment. Acidity is measured by an acidic conductivity device 17 which generates a signal for controlling a pump 19 by which acid replenishment may be added through 21 or in another embodiment the operation of the pump 19 is in a predetermined fixed relationship to the operation of the pump 14. A timer 23 is provided for starting each replenishment cycle. The temperature of the solution may be recorded by a sensor 13 and the said predetermined desired value of free fluoride may be varied automatically in response to and to compensate for the deviation of the actual temperature from a predetermined temperature. Measurement of acidity by pH is said to give unsatisfactory results.

Description

Die Erfindung betrifft ein Verfahren zur Ergänzung von Reinigerlösungen bei der Reinigung von Aluminiumoberflächen mit sauren, Fluoridionen enthaltenden wäßrigen Lösungen, bei denen der Fluoridionengehalt gemessen und mit Fluoridionen und Säure ergänzt wird.The invention relates to a method for supplementing cleaning solutions in the cleaning of aluminum surfaces with acidic aqueous solutions containing fluoride ions, in which the fluoride ion content is measured and supplemented with fluoride ions and acid.

Es ist bekannt, daß Aluminiumgegenstände, z.B. Aluminiumdosen, durch Kontakt mit einer wäßrigen, Fluoridionen enthaltenden Lösung gereinigt werden können. Derartige Lösungen enthalten z.B. Fluoridionen und Schwefelsäure (GB-PS 1 454 974).It is known that aluminum objects, e.g. Aluminum cans can be cleaned by contact with an aqueous solution containing fluoride ions. Such solutions contain e.g. Fluoride ions and sulfuric acid (GB-PS 1 454 974).

In der Praxis ist es erforderlich, Reinigerlösungen . während ihres Gebrauches mit Fluoridionen und Säure zu ergänzen. Dabei bereitet insbesondere die Messung und Aufrechterhaltung der Fluoridionenkonzentration Schwierigkeiten. Mit der Entwicklung fluoridionenempfindlicher Elektroden, z.B. gemäß US-PS 3 431 182, wurde eine Möglichkeit zur recht genauen Ermittlung der Beschaffenheit von Reinigerlösungen geschaffen. Verfahren, wie in der GB-PS 14 54 974 beschrieben, haben kommerzielle Bedeutung erlangt und beruhen auf einer automatischen Messung des Gehaltes an freien Fluoridionen in der Lösung.In practice it is necessary to use cleaning solutions. to be supplemented with fluoride ions and acid during use. The measurement and maintenance of the fluoride ion concentration are particularly difficult. With the development of electrodes sensitive to fluoride ions, for example according to US Pat. No. 3,431,182, a possibility has been created for the fairly precise determination of the nature of cleaning solutions. Procedure as in the GB-PS 14 54 974 described, have gained commercial importance and are based on an automatic measurement of the content of free fluoride ions in the solution.

In der Praxis werden derartige Regelverfahren durchgeführt, indem man durch geeignete Heiz- und/oder Kühlsysteme die Temperatur des Behandlungsbades auf einem konstanten Wert hält und sowohl den Fluoridionengehalt als auch den Säuregehalt durch Messung des Gehaltes an freien Fluoridionen bzw. des PH-Wertes und Ergänzung mit Fluorid und Säure je nach Abweichung vom jeweiligen Sollwert konstant hält. Obgleich es gewisse Schwierigkeiten bereitet, die Kontrolle und Ergänzung in einer Weise durchzuführen, daß einheitliche Ergebnisse erzielt werden können, hat sich die genannte Methode in die Praxis eingeführt.`In practice, such control methods are carried out by keeping the temperature of the treatment bath at a constant value by means of suitable heating and / or cooling systems, and both the fluoride ion content and the acid content by measuring the content of free fluoride ions or the pH value and supplementing it with fluoride and acid, depending on the deviation from the respective setpoint. Although there are certain difficulties in carrying out the control and supplementation in such a way that uniform results can be achieved, the above-mentioned method has been put into practice

Auf dem Gebiet der Oberflächenbehandlung von Metallen sind neben dem genannten Verfahren zahlreiche andere bekanntgeworden, beispielsweise auch das gemäß GB-PS 2 050 645, das insbesondere der Kontrolle von Zinkphosphatbädern dient.In the field of surface treatment of metals, numerous others have become known in addition to the method mentioned, for example that according to GB-PS 2 050 645, which is used in particular for the control of zinc phosphate baths.

Den bekannten Verfahren ist der Nachteil gemeinsam, daß eine präzise Anzeige hinsichtlich der zu ergänzenden Chemikalienmengen eine konstante Temperatur des Behandlungsbades voraussetzt, eine Voraussetzung, die jedoch meist nicht gegeben ist. Die herkömmliche Dosierung der Ergänzungschemikalien auf einen Soll-Wert ausgehend von einem gemessenen Ist-Wert führt häufig zu einer Uberdosierung der zu ergänzenden Chemikalien, da der Konzentrationsausgleich zwischen zugeführter Ergänzungslösung und Behandlungslösung in der Praxis häufig in der Größenordnung von mehren Minuten liegt.The known methods have the disadvantage in common that a precise indication of the amounts of chemicals to be added requires a constant temperature of the treatment bath, a requirement which is usually not given. The conventional metering of the supplementary chemicals to a target value based on a measured actual value often leads to an overdose of the chemicals to be supplemented, since the concentration balance between the supplemental solution and the treatment solution supplied in practice is often of the order of several minutes.

Aufgabe der Erfindung ist es, ein Verfahren zur Ergänzung von Reinigerlösungen bereitzustellen, daß die Nachteile der bekannten Verfahren vermeidet, einfach in der Durchführung ist und keinen hohen apparativen Aufwand erforderlich macht.The object of the invention is to provide a method for supplementing cleaning solutions which avoids the disadvantages of the known methods, is simple to carry out and does not require a high outlay on equipment Lich.

Die Aufgabe wird gelöst, indem das Verfahren der eingangs genannten Art entsprechend der Erfindung derart ausgestaltet wird, daß man die Dosierung der Chemikalienmenge in Abhängigkeit von der Abweichung vom automatisch temperaturkorrigierten und für einen konstanten Beizabtrag erforderlichen Soll-Wert der Fluoridionenkontration regelt.The object is achieved by designing the method of the type mentioned at the outset in accordance with the invention in such a way that the metering of the quantity of chemicals is regulated as a function of the deviation from the automatically corrected setpoint of the fluoride ion concentration and required for constant pickling removal.

Die Wirksamkeit einer Fluoridionen enthaltenden Reinigerlösung ist von ihrer Temperatur abhängig. Deswegen wird üblicherweise große Sorgfalt darauf verwendet, die Temperatur so konstant wie möglich zu halten. Obgleich das vorliegende erfindungsgemäße Verfahren eine Konstanthaltung der Temperatur der Reinigerlösung nicht ausschließt, liegt ihr erheblicher Vorteil darin, daß der Fluoridionengehalt automatisch auf den jeweiligen erforderlichen Wert, der Abweichungen von der Soll-Temperatur ausgleicht, eingestellt wird. So wird der Fluoridionengehalt bei einem Anstieg der Temperatur über den vorgesehenen Temperatur-Soll-Wert hinaus reduziert und damit ein konstanter Beizabtrag erzielt.The effectiveness of a cleaning solution containing fluoride ions depends on its temperature. Therefore, great care is usually taken to keep the temperature as constant as possible. Although the present method according to the invention does not rule out keeping the temperature of the cleaning solution constant, its considerable advantage lies in the fact that the fluoride ion content is automatically adjusted to the respective required value, which compensates for deviations from the target temperature. In this way, the fluoride ion content is reduced when the temperature rises above the intended temperature setpoint and thus a constant pickling removal is achieved.

Das erfindungsgemäße Verfahren weist Vorrichtungsteile zur Messung des Fluoridionengehaltes, Vorrichtungsteile zur Messung der Temperatur der Reinigerlösung sowie Korrekturelemente (override means) auf, um den Wert hinsichtlich Fluoridionengehalt in Abhängigkeit von bzw. zum Ausgleich von Änderung bei der ermittelten Temperatur - jeweils bezogen auf ein vorgegebenen Temperaturwert - zu ändern.The inventive method comprises device parts for measuring the F luoridionengehaltes, parts of the device for measuring the temperature of the detergent solution as well as correction elements (override Means) on to the value in terms of fluoride ion content as a function of or compensate for change in the detected temperature - in each case based on a predetermined Temperature value - to change.

Die Vorrichtungsteile zur Messung des Fluoridionengehaltes der Reinigerlösung sind zweckmäßigerweise mit einem Gerät zur Erzeugung eines Signals bei Abweichung vom vorgegebenen Wert verbunden. Hierzu ist eine optische Anzeige, z.B. in Form eines Zeigerinstrumentes, geeignet. Die Vorrichtungsteile zur Messung der Temperatur und - bei evt. auftretenden Abweichungen vom Soll-Wert - zur Anpassung beinhaltet Elemente zur Aufgabe eines Signals auf das Anzeigeinstrument. Dies hat zur Folge, daß ein Fluoridionengehalt angezeigt wird, der je nach Art der Temperaturabweichung höher oder tiefer als der tatsächlich vorhandene Fluoridionengehalt ist. Der solcherart erhaltene temperaturkorrigierte Wert steuert letztlich die Dosierung der Ergänzungslösung und gewährt den konstanten Beizabtrag.The device parts for measuring the fluoride ion content of the cleaning solution are expediently connected to a device for generating a signal in the event of a deviation from the predetermined value. An optical display, for example in the form of a pointer instrument, is suitable for this. The device parts for measuring the temperature and - if necessary. Deviations from the target value that occur - for adaptation contains elements for applying a signal to the display instrument. The result of this is that a fluoride ion content is displayed which, depending on the type of temperature deviation, is higher or lower than the actual fluoride ion content. The temperature-corrected value obtained in this way ultimately controls the dosage of the supplementary solution and ensures constant removal of the pickling.

Beispielsweise wäre bei- Anstieg der Temperatur um 10 °C der auf dem Anzeigegerät eingezeigte Fluoridionengehalt etwa doppelt so hoch wie der in der Reinigerlösung tatsächlich vorhandene Wert. Das bedeutet für die praktische Arbeitsweise, daß bei Anstieg der Temperatur der Reinigerlösung um 10 °C der tatsächlich gemessene Fluoridionengehalt in Folge der Regelung auf etwa die Hälfte reduziert wird. Bei Abfall der Temperatur um 10 °C unter die Soll-Temperatur würde ein entsprechend verringerter Gehalt an Fluoridionen angezeigt, der aber durch die Regelung entsprechend erhöht wird.For example, if the temperature rose by 10 ° C, the fluoride ion content shown on the display device would be about twice as high as the value actually present in the cleaning solution. In practical terms, this means that when the temperature of the cleaning solution rises by 10 ° C, the fluoride ion content actually measured is reduced to about half as a result of the regulation. If the temperature drops by 10 ° C below the target temperature, a correspondingly reduced content of fluoride ions would be indicated, but this is increased accordingly by the control.

Die für die Ergänzung der Reinigerlösung erforderliche Säuremenge kann in Abhängigkeit von einer getrennten Säuremessung, z.B. mittels einer Leitfähigkeits- oder PH-Messung, erfaßt werden. Vorzugsweise und in weiterer Ausgestaltung der Erfindung erfolgt jedoch die Säurezugabe ohne separate Säuremessung, sondern in Verbindung mit der Fluoridionenzugabe mittels einer Dosiervorrichtung, die ebenfalls durch die Messung des Fluoridionengehaltes der Reinigerlösung gesteuert wird. Hierzu wird anhand von Erfahrungswerten oder durch Vorversuche eine bestimmte Beziehung zwischen Fluoridionenergänzung und Säureergänzung ermittelt und eingestellt. Beispielsweise kann die Dösiervorrichtung für die Fluoridionen enthaltende Lösung bei bestimmter Fördermenge während einer Zeit, die von der Ab-weichung des gemessenen Fluoridionengehaltes vom Soll-Wert abhängig ist, betrieben werden und gleichzeitig eine Dosiervorrichtung für Säure für einen Zeitraum, der in vorgegebener Relation zur Laufzeit der Dosiervorrichtung für die Fluorionendosierung steht, in Gang gesetzt werden. Eine derartige gekoppelte und allein vom Fluoridionengehalt der Reinigerlösung gesteuerte Säureergänzung ist unter normalen Betriebsbedingungen mit Abweichungen hinsichtlich der Säureergänzung von maximal 5 % verbunden.The amount of acid required to supplement the cleaning solution can be determined as a function of a separate acid measurement, for example by means of a conductivity or pH measurement. However, preferably and in a further embodiment of the invention, the acid is added without a separate acid measurement, but in conjunction with the fluoride ion addition by means of a metering device, which is also controlled by measuring the fluoride ion content of the cleaning solution. For this purpose, a certain relationship between fluoride ion supplementation and acid supplementation is determined and set on the basis of empirical values or by preliminary tests. For example, the Dösiervorrichtung can be used for the fluoride ion-containing solution at a certain flow rate during a time-b deviation from the A of the measured fluoride ion content from the desired value is dependent, and are operated at the same time a Do Siervorrichtung for acid for a period of time, which is in a predetermined relation to the running time of the metering device for fluorine dosing, in motion. Such a coupled acid supplement, which is controlled solely by the fluoride ion content of the cleaning solution, is associated under normal operating conditions with deviations in the acid supplement of at most 5%.

Falls der Durchsatz von Aluminiumoberfläche gering ist oder - beispielsweise in Folge von Betriebsunterbrechungen - kein Aluminium durchgesetzt wird, oder aber das Volumen der Behandlungslösung sich ungewöhnlich verändert, kann der Fall eintreten, daß zwar kein oder nur wenig Fluorid, hingegen aber Säure verbraucht wird. Demzufolge würde die Messung des Fluoridionengehaltes nur zu einer kurzen oder im Extremfall zu gar keiner Dosierung von Ergänzungslösung führen. Für diesen Fall sieht die Regelvorrichtung eine Sicherheitsschaltung vor, die die Zugabe von Säure in vorgegebenen zeitlichen Intervallen gewährleistet und zwar auch dann, wenn keine Fluoridionen zugesetzt werden. Das heißt, wenn-ausreichend Säure in Folge der üblichen Ergänzung zugesetzt wird, tritt die Sicherheitsschaltung nicht in Tätigkeit. Fällt jedoch die regelmäßige, durch Messung des Fluoridionengehaltes gesteuerte Ergänzung von Fluoridionen und damit die gleichzeitige Zugabe von Säure aus, setzt die Sicherheitsschal- , tung die Dosierung für Säure von Zeit zur Zeit solange in Gang, daß der Säuregehalt auf einem angemessenen Niveau liegt. Die Zeit, nach der die Sicherheitsschaltung aktiviert wird, kann durch Versuche in einfachster Weise bestimmt werden. Sie hängt im allgemeinen vom normalen Verlust an Reinigerlösung, dem freien Säuregehalt der Reinigerlösung, der Konzentration der Ergänzungslösung für Säure und der Dosierleistung der Dosiervorrichtung für die Säure ab.If the throughput of aluminum surface is low or - for example as a result of business interruptions - no aluminum is passed through, or if the volume of the treatment solution changes abnormally, it can happen that no or only little fluoride but acid is consumed. As a result, the measurement of the fluoride ion content would only lead to a short or, in extreme cases, no dosing of the supplemental solution. In this case, the control device provides a safety circuit which ensures the addition of acid at predetermined time intervals, even if no fluoride ions are added. This means that if sufficient acid is added as a result of the usual addition, the safety circuit does not operate. However, if the regular addition of fluoride ions controlled by measurement of the fluoride ion content and thus the simultaneous addition of acid fails, the safety circuit starts the metering for acid from time to time so long that the acid content is at an appropriate level. The time after which the safety circuit is activated can be determined in a very simple manner by experiments. It generally depends on the normal loss of detergent solution, the free acidity of the detergent solution, the concentration of the make-up solution for acid and the metering capacity of the metering device for the acid.

Eine weitere bevorzugte Ausführungsform der Erfindung besteht darin, die Ergänzung in bestimmten vorgegebenen zeitlichen Intervallen vorzunehmen. Dabei werden Fluoridionen, gegebenenfalls auch damit gekoppelt Säure bei vorgegebener Förderleistung der Dosiervorrichtungen in Ab-hängigkeit vom ermittelten Fluoridionengehalt der Reinigerlösung über einen bestimmten Zeitraum zudosiert. Ansonsten ist auch hier eine Dosiervorrichtung für die Fluoridionen enthaltende Lösung, eine Dosiervorrichtung für die Säure sowie eine Vorrichtung zur Messung der Fluoridionengehaltes der Reinigerlösung vorgesehen.Another preferred embodiment of the invention is to supplement the given in certain time intervals. In this case, fluoride ions are also optionally coupled therewith acid at a predetermined delivery rate of the metering devices in A b-dependence of the determined metered fluoride ion content of the cleaning solution for a certain period. Otherwise, a metering device for the solution containing fluoride ions, a metering device for the acid and a device for measuring the fluoride ion content of the cleaning solution are also provided here.

Die beim erfindungsgemäßen Verfahren eingesetzte elektronische Schaltung weist eine veränderbare, ein Tastverhältnis (mark/space ratio) gebende Schaltung, die mit einem Taktgeber verbünden ist, auf. Durch den Taktgeber ist der zeitliche Abstand mit dem die Dosiervorrichtungen in Gang gesetzt werden, wählbar. Die Meßeinrichtung wird zweckmäßigerweise an einer Stelle installiert, an der die unmittelbar im Einsatz befindliche Reinigerlösung anfällt. Das heißt, bei der bevorzugten Reinigung im Spritzverfahren wird die Meßeinrichtung vorteilhafterweise mit den mit den Umlaufpumpen in Verbindung stehenden Rohrleitungen verbunden.The electronic circuit used in the method according to the invention has a variable circuit which gives a pulse duty factor (mark / space ratio) and is connected to a clock generator. The time interval at which the metering devices are started can be selected by the clock generator. The measuring device is expediently installed at a point at which the cleaning solution which is directly in use is obtained. That is, in the preferred cleaning by spraying, the measuring device is advantageously connected to the pipelines connected to the circulation pumps.

Die Laufdäuer der taktweise geschalteten Dosiervorrichtungen wird zweckmäßigerweise derart gewählt, daß sie bei normalen Betrieb der Reinigungsanlage etwa die halbe Zeit eines Taktintervalles dosieren. Bei einer Taktzeit von 4 Minuten betrüge ihre Laufdauer also etwa 2 Minuten. Die Förderleistung der Dosiervorrichtungen ist dabei auf den Bedarf an Ergänzungslösung anzupassen.The running time of the cyclically switched metering devices is expediently chosen such that they meter about half the time of a cycle interval during normal operation of the cleaning system. With a cycle time of 4 minutes, their running time would be about 2 minutes. The delivery rate of the dosing devices must be adapted to the need for a supplementary solution.

Sofern bei Einsatz des erfindungsgemäßen Verfahrens der Durchsatz an Aluminiumoberfläche sinkt, steigt der Fluoridionengehalt der Reinigerlösung an. Bei der nächsten, durch den Taktgeber fixierten, erneuten Inbetriebnahme der Dosiervorrichtung wird dementsprechend deren Laufdauer verkürzt. Analog wird bei erhöhtem Durchsatz von Aluminiumoberfläche beim nächsten Ergänzungszyklus die Laufdauer der Dosiervorrichtung entsprechend verlängert.If the throughput on the aluminum surface drops when the method according to the invention is used, the fluoride ion content of the cleaning solution increases. The next time the metering device is put into operation again, which is fixed by the clock generator, its operating time is shortened accordingly. The same goes for increased through set of aluminum surface for the next supplementary cycle the operating time of the dosing device is extended accordingly.

Aus Sicherheitsgründen kann die Regelvorrichtung mit einer Zusatzeinrichtung verbunden sein, die verhindert, daß die Dosiervorrichtungen in Folge betrieblicher Störungen mit ungewöhnlich kurzer oder langer Laufzeit innerhalb eines Ergänzungszyklus geregelt werden. Dieser abnormale Betriebszustand kann. durch Warnanzeigevorrichtungen angezeigt werden.For safety reasons, the control device can be connected to an additional device which prevents the metering devices from being controlled as a result of operational malfunctions with an unusually short or long runtime within a supplementary cycle. This abnormal operating condition can. are indicated by warning indicators.

Zur Messung des Fluoridionengehaltes der Reinigerlösung können bekannte Elektrodensysteme, z.B. das mit einem Stromschlüssel arbeitende System gemäß US-PS 3 431 182 verwendet werden.To measure the fluoride ion content of the cleaning solution, known electrode systems, e.g. the system with a power key according to US Pat. No. 3,431,182 can be used.

Die Verwendung derartiger Stromschlüssel ist jedoch mit dem Nachteil verbunden, daß sie in Folge Verlust von Elektrolytlösung zu fehlerhaften Anzeigen führen können. Abhilfe kann insoweit geschaffen weLden, wenn der Stromschlüssel einen Behälter für die Elektroydlösung aufweist, der mit einer zusätzlichen Warnelektrode verbunden ist. Sie ist mit der Bezugselektrode derart gekoppelt und in der Weise im Behälter für Elektrolytlösung angeordnet, daß sie ein Warnsignal abgibt, sobald das Niveau des Elektrolyt unter eine bestimmte Marke sinkt.However, the use of such power keys has the disadvantage that they can lead to incorrect displays as a result of loss of electrolyte solution. This can be remedied if the power key has a container for the electro-hydroxide solution, which is connected to an additional warning electrode. It is coupled to the reference electrode and arranged in the electrolyte solution container in such a way that it emits a warning signal as soon as the level of the electrolyte drops below a certain level.

Ein solcher Stromschlüssel weist demzufolge ein;n Behälter für den Elektrolyt sowie in den Elektrolyt eintauchende Bezugs- bzw. Warnelektroden auf. Der unterste Teil der Warnelektrode befindet sich in einer Position, die über der ist, bei der die Bezugselektrode unwirksam wird. Unter normalen Betriebsbedingungen besteht ein elektrischer Kontakt zwischen Warn- und Bezugselektrode. Sinkt das Elektrolytniveau im Behälter unter eine bestimmte Höhe, taucht die Warnelektrode nicht mehr in den Elektrolyt ein. Die sich dadurch verändernde Potentialdifferenz zwischen Bezugs- und Warnelektrode löst ein Warnsignal aus, das in beliebiger Weise, z.B. akustisch oder optisch, umgesetzt werden kann.Such a current key accordingly has a container for the electrolyte and reference or warning electrodes immersed in the electrolyte. The lowest part of the warning electrode is in a position above that at which the reference electrode becomes ineffective. Under normal operating conditions there is electrical contact between the warning and reference electrodes. If the electrolyte level in the container drops below a certain level, the warning electrode no longer dips into the electrolyte. The thus changing potential difference between the reference and warning electrodes triggers a warning signal which can be implemented in any way, for example acoustically or optically.

Der im Stromschlüssel verwendete Elektrolyt ist meist eine wäßrige Caliumchloridlösung. Die Warnelektrode kann z.B. aus einem Edelstahlstab bestehen. Als Bezugselektrode dient gewöhnlich eine Kalomelelektrode.The electrolyte used in the power key is usually an aqueous potassium chloride solution. The warning electrode can e.g. consist of a stainless steel rod. A calomel electrode is usually used as the reference electrode.

Die Erfindung wird anhand der Figur beispielsweise und näher erläutert.The invention is explained for example and in more detail with reference to the figure.

Eine auf Fluoridionen ansprechende Elektrode 1 ist in ein Behandlungsbad 2 eingetaucht und mit einer Bezugselektrode 3 (Kalomelelektrode) durch eine herkömmliche Schaltung 4 verbunden. Die Bezugselektrode 3 ist in eine wäßrige Caliumchlorid-Elektrolylösung, die sich in einem Behälter 6 befindet eingetaucht. Ein Rohr 7 endet in einem keramischen porösen Stopfen 8, der seinerseits in das Behandlungsbad 2 eintaucht. Eine stabförmige Warnelektrode 9 aus Edelstahl ist derart in der Elektrolytlösung 5 fixiert, daß ihr unterstes Ende oberhalb des Niveaus der Oberkante der Bezugselektrode 3 endet.An electrode 1 responsive to fluoride ions is immersed in a treatment bath 2 and connected to a reference electrode 3 (calomel electrode) by a conventional circuit 4. The reference electrode 3 is immersed in an aqueous potassium chloride electrolyl solution, which is located in a container 6. A tube 7 ends in a ceramic porous stopper 8, which in turn is immersed in the treatment bath 2. A rod-shaped warning electrode 9 made of stainless steel is fixed in the electrolyte solution 5 in such a way that its lower end ends above the level of the upper edge of the reference electrode 3.

Eine elektrische Verbindung zwischen Bezugselektrode 3 und Warnelektrode 9 ist durch Vorrichtungsteile 10 angedeutet. Diese schließen eine geeignete Warnvorrichtung ein, die bei unerwünschtem Überstreiten der Potentialdifferenz zwischen den Elektroden 3 und 9 tätig wird.An electrical connection between reference electrode 3 and warning electrode 9 is indicated by device parts 10. These include a suitable warning device which operates when the potential difference between the electrodes 3 and 9 is undesirably exceeded.

Die Reinigerlösung hat üblicherweise eine Temperatur von 30 bis 70 °C, einen PH-Wert unter 3, meist zwischen 1 und 2,5, insbesondere 1,5, sowie einen Gehalt an freien Fluoridionen von 0,05 bis 10, vorzugsweise 0,1 bis 5 und insbesondere von 0,8 mg/l. Eine solche Reinigerlösung kann in einfachster Weise mit Flußsäure oder anderen Fluoridionen liefernden Substanzen und Schwefelsäure, ggf. unter zusätzlicher Verwendung von Tensid, angesetzt werden. Sie dient zur üblichen Spritzreinigung von z.B. Aluminiumdosen.The cleaning solution usually has a temperature of 30 to 70 ° C, a pH below 3, usually between 1 and 2.5, in particular 1.5, and a free fluoride ion content of 0.05 to 10, preferably 0.1 up to 5 and in particular from 0.8 mg / l. Such a cleaning solution can be easily done with hydrofluoric acid or other fluoride ion-providing substances and sulfuric acid, if necessary with the additional use of surfactant. It is used for the usual spray cleaning of, for example, aluminum cans.

Der Fluoridionengehalt wie die Temperatur werden kontinuierlich überwacht. Die Temperatur wird als digitale Anzeige dargestellt, der temperaturkorrigierte Fluoridionengehalt durch einen Anzeiger, wie weiter oben erläutert, dargestellt. Mittels eines-Taktgebers und einer ein Tastverhältnis gebenden Schaltung (mark/space ratio circuit) wird alle 4 Minuten eine Ergänzungsoperation in Gang gesetzt, wobei zur Konstanthaltung des Fluoridionengehaltes eine Pumpe zur Versorgung mit fluoridhaltiger Ergänzungslösung in vorbestimmter Weise für eine Zeit, die von der Position des Anzeigegerätes abhängt, in Tätigkeit gesetzt wird. Gleichzeitig setzt eine zweite Pumpe während einer Zeit, die in einem vorgegebenen Verhältnis zur Ergänzungsdauer der Fluoridionenzugabe steht, Schwefelsäure zu.The fluoride ion content and the temperature are continuously monitored. The temperature is shown as a digital display, the temperature-corrected fluoride ion content is shown by an indicator, as explained above. A supplementary operation is started every 4 minutes by means of a clock and a mark / space ratio circuit, whereby, in order to keep the fluoride ion content constant, a pump for supplying fluoride-containing supplementary solution in a predetermined manner for a time dependent on the position depends on the display device, is activated. At the same time, a second pump adds sulfuric acid during a time that is in a predetermined ratio to the addition period of the fluoride ion addition.

Claims (3)

1. Verfahren zur Ergänzung von Reinigerlösungen bei der Reinigung von Aluminiumoberflächen mit sauren, Fluoridionen enthaltenden wäßrigen Lösungen, bei denen der Fluoridionengehalt gemessen und mit Fluoridionen und Säure ergänzt wird, dadurch gekennzeichnet, daß man die Dosierung der Chemikalienmenge in Abhängigkeit von der Abweichung vom automatisch temperaturkorrigierten und für einen konstanten Beizabtrag erforderlichen Soll-Wert des Fluoridionengehaltes regelt.1. A method for supplementing cleaning solutions in the cleaning of aluminum surfaces with acidic, fluoride ion-containing aqueous solutions in which the fluoride ion content is measured and supplemented with fluoride ions and acid, characterized in that the dosage of the amount of chemicals depending on the deviation from the automatically temperature-corrected g and necessary for a constant pickling removal target value of fluoride ions ehaltes controls. 2. Verfahren nach Anspruch 1, dadurch gekennzeichnet, daß man die Ergänzung der Säure mit der der Fluoridionen automatisch koppelt.2. The method according to claim 1, characterized in that one couples the addition of the acid with that of the fluoride ions automatically. 3. Verfahren nach Anspruch 1 oder 2, dadurch gekennzeichnet, daß man die Ergänzung der Fluoridionen und ggf. der Säure in bestimmten zeitlichen Intervallen einleitet und die Chemikalienmenge bei vorgegebener Förderleistung der Dosiervorrichtungen über die Dosierdauer regelt.3. The method according to claim 1 or 2, characterized in that one introduces the addition of fluoride ions and possibly the acid at certain time intervals and regulates the amount of chemicals at a given delivery rate of the metering devices over the metering time.
EP82109310A 1981-10-09 1982-10-08 Method for the replenishment of cleaning solutions Withdrawn EP0077041A1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8130529 1981-10-09
GB8130529 1981-10-09

Publications (1)

Publication Number Publication Date
EP0077041A1 true EP0077041A1 (en) 1983-04-20

Family

ID=10525053

Family Applications (1)

Application Number Title Priority Date Filing Date
EP82109310A Withdrawn EP0077041A1 (en) 1981-10-09 1982-10-08 Method for the replenishment of cleaning solutions

Country Status (7)

Country Link
EP (1) EP0077041A1 (en)
JP (1) JPS5881980A (en)
AU (1) AU8910382A (en)
BR (1) BR8205926A (en)
DE (1) DE3237553A1 (en)
GB (1) GB2107359B (en)
ZA (1) ZA827263B (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002079545A1 (en) * 2001-03-30 2002-10-10 Alcan International Limited Method of controlling a chemical cleaning line for aluminum strip

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20090229995A1 (en) * 2008-03-14 2009-09-17 Eci Technology, Inc. Analysis of fluoride at low concentrations in acidic processing solutions
CN110484750A (en) * 2019-08-21 2019-11-22 陕西美泰节能科技有限公司 A kind of aluminium alloy particle reuse means and processing technology

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1454974A (en) * 1974-02-14 1976-11-10 Amchem Prod Processes for cleaning aluminium
US4124407A (en) * 1975-08-25 1978-11-07 Amchem Products, Inc. Method for cleaning aluminum at low temperatures

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5035033A (en) * 1973-08-02 1975-04-03
JPS5355307A (en) * 1976-10-29 1978-05-19 Yoshio Asahi Detergent for aluminum

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB1454974A (en) * 1974-02-14 1976-11-10 Amchem Prod Processes for cleaning aluminium
US4124407A (en) * 1975-08-25 1978-11-07 Amchem Products, Inc. Method for cleaning aluminum at low temperatures

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2002079545A1 (en) * 2001-03-30 2002-10-10 Alcan International Limited Method of controlling a chemical cleaning line for aluminum strip
US6524391B2 (en) 2001-03-30 2003-02-25 Alcan International Limited Method for automatically controlling a chemical cleaning stage of a metal strip cleaning line
US6595222B2 (en) 2001-03-30 2003-07-22 Alcan International Limited Chemical cleaning apparatus for cleaning metal strip

Also Published As

Publication number Publication date
DE3237553A1 (en) 1983-05-05
AU8910382A (en) 1983-04-14
GB2107359B (en) 1986-01-22
ZA827263B (en) 1984-05-30
BR8205926A (en) 1983-09-06
GB2107359A (en) 1983-04-27
JPS5881980A (en) 1983-05-17

Similar Documents

Publication Publication Date Title
DE3152914C2 (en) Tank level meter for a motor vehicle
DE3237396C2 (en)
DE3127822C2 (en)
EP0139874B1 (en) Circuit for thermo-electrical level measurement
DE4339472C2 (en) Device for generating a test gas
DE3030664A1 (en) METHOD FOR DETERMINING THE CURRENT EXPLOITATION OF GALVANIC BATHS
DE2937227C2 (en) Method for calibrating an electrometric pH measuring device and a device for carrying out the method
EP0166034A1 (en) Method and arrangement for electrothermal, ambient temperature compensated level measurement
EP2212659B1 (en) Impedance-scanning quartz crystal microbalance
DE10100239A1 (en) Method for determining the remaining operating time of a potentiometric measuring probe, device for carrying out the method and its use
EP0077041A1 (en) Method for the replenishment of cleaning solutions
DE2729945C2 (en) Method of operating an electrolytic cell
EP0019856A1 (en) Method and apparatus for volumetrically measuring liquids
DE3024493C2 (en)
DE2114972A1 (en) Procedure for aligning a thin film arrangement
DE2648538C2 (en) Process for automatically controlled constant maintenance of the composition of baths and device for carrying out the process
DE3401100A1 (en) METHOD AND DEVICE FOR CONTROLLING THE TEMPERATURE WITHIN A METAL HALOGEN BATTERY
DE2050126A1 (en) Method for determining the actual resistance value of an electrolytic cell for the control of constant cell resistance
DE1034885B (en) Method for measuring changes in the degree of unsaturation of animal or vegetable oils or fatty acids derived therefrom
DE102012105961A1 (en) Dispensing device for delivering cleaning fluid containing ions, has electrodes, where device is operated in continuous process and measurement indicative for ion concentration, is performed in course of delivering cleaning fluid
EP4220153A1 (en) Energy-efficient method for continuously measuring the quality of a liquid and measuring device for carrying out the method
DE10163017B4 (en) Method for operating a reaction vessel
DE1935231A1 (en) Current yield determination of electrolytic - baths
EP2357270A1 (en) Bleed and feed device and method
DE2523768A1 (en) METHOD OF DETERMINING THE CONCENTRATION OF SOLUBLE MATERIALS AND DEVICE FOR ITS IMPLEMENTATION

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

AK Designated contracting states

Designated state(s): AT BE CH DE FR IT LI NL SE

17P Request for examination filed

Effective date: 19831004

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE APPLICATION HAS BEEN WITHDRAWN

18W Application withdrawn

Withdrawal date: 19850619

RIN1 Information on inventor provided before grant (corrected)

Inventor name: BECK, RICHARD ANDREW