SI20535A - Automatic regulation and control of cleanising baths - Google Patents

Abstract

The invention relates to a method for controlling cleansing baths, characterized in that at least two of i) tenside contents, ii) inorganically and/or organically bound carbon load, iii) alkalinity, are measured in a program-controlled manner and in that a) depending on the result of the measurements additional components are added and/or one or more bath maintenance measures are initiated and/or b) the results of the measurements and/or data derived from the measurement results are transmitted to at least one remote destination which is situated in a room different from the one housing the device for carrying out the above measurements.

Description

The invention relates to a process for the automatic control and control of cleaning baths, especially cleaning baths in the metalworking or automotive industries. The essence of the invention is that at least two selected control parameters are automatically and programmatically controlled and the results of determinations and / or derived data are transmitted to a remote target location not located in the immediate vicinity of the treatment bath. Depending on the results of the determinations, further determinations and / or bath care measures can be performed by the program-controlled or by command from a remote destination. In addition, according to the results of the determinations, control measurements can be implemented programmatically or on a command. The remote target site may be located, for example, in some parent process control system, in the plant control center in which the treatment bath is located, as well as at some location outside the plant.

cleaning metal parts before their further processing is a standard task in the metal processing industry. Metal parts can be contaminated with pigment dirt, dust, metal scrap, anti-corrosion oils, coolant oils or forming aids. Before further processing, especially against corrosion protection (eg phosphating, chromating, anodizing, reaction with complex fluorides, etc.) or before painting, this impurity must be removed with suitable cleaners. Injection, immersion, or combination procedures may be required for this purpose.

Industrial cleaners in the metalworking industry are generally alkaline (pH values above 7. eg 912). Their basic components are alkali (alkali metal hydroxides, -carbonates, -silicates, -phosphates, -borates) as well as non-ionic and / or anionic surfactants. Often they contain cleaning agents as additional auxiliary components of the complexing agent igluconates, polyphosphates, aminocarboxylic acid salts such as ethylenediaminetetraacetate or nitriloacetate, phosphoric acid salts such as e.g. salts of hydroxyethanediphosphonic acid, phosphonobutantricarboxylic acid or other phosphonic or phosphonocarboxylic acids), anticorrosive agents such as e.g. carboxylic acid salts of 6-12 C atoms, alkanolamines and foam inhibitors such as e.g. endgruppenverschlossene alkoxylates of alcohols with 6 - 12 C atoms in the alkyl residue, if the scrub baths do not contain any anionic surfactants, then cationic surfactants may also be used.

As a rule, non-ionic surfactants contain ethoxylate, propoxylate and / or ethoxylate / propoxylate of alcohols or alkylamines of 6-12 C atoms in an alkyl residue, which may also be closed in the end group. Alkyl sulfates and alkyl sulfonates are widely used as anionic surfactants. Alkylbenzenesulfonates are still encountered, but are ecologically unfavorable. Cationic surfactants are particularly suitable cationic alkylammonium compounds with at least one alkyl radical having 8 or more C atoms.

Alkalis in the cleaning bath contribute to their cleaning capacity. For example, they soothe sordid demons, such as greases, making them water soluble. In addition, they contribute to the dissolution of insoluble particles of dirt from the metal surface so that the surfaces are adsorbed

The OH ions are negatively charged, thereby creating electrostatic repulsion. Such reactions, including the Ausschleppung, are used as needed, the alkalinity is consumed so that the cleaning effect is reduced over time. As a result, it is common for the alkalinity of the cleaning baths to be checked over time and, if necessary, to supplement the solution with new active ingredients or to recover completely. These tests shall be carried out manually or locally with the aid of a titrirneaa automaton. As a rule, the alkalinity is checked by titration with strong acid. Service personnel assess the alkalinity based on acid consumption and take the required steps, such as: bath replenishment or refurbishment. This currently normal procedure presupposes that, during the required inspection, servicing personnel are located near the cleaning bath. the shorter the control intervals are desirable, the greater the load on the control personnel by the control measurements.

EP-A 806 244 discloses a process for automatically determining the pH of a solution and, in the event of deviation, the acid or alkali is dosed automatically. The primary purpose of this document is to maintain the pH of a fluid stream at a predetermined value. Acid-base titration is not followed by this procedure. This requires that the device in place be controlled for functional ability. It is not possible to interfere with the pH measurements from a remote location and to act on dosing.

The state of the art allows non-ionic surfactants to be determined in aqueous process solution such as e.g. manually in the cleaning bath using a color indicator. It is usually done by adding from the process solution a reagent which forms a color complex with non-ionic surfactants. Preferably, this color complex is extracted into an organic solvent that is not miscible with water in any proportion, and then its light absorption is determined photometrically at a given wavelength. For example, tetrabromophenolphthaleinethyl ester may be used as the reagent for the formation of the color complex. Prior to extraction into an organic solvent, preferably into a chlorinated hydrocarbon, the process solution is replaced with a pH 7 buffer system.

It is further known to determine non-ionic surfactants in the presence of ionic surfactants. In doing so, ionic surfactants are eliminated from the sample by an ion exchanger. In an ion exchanger, unbound non-ionic surfactants are determined by the refractive index of the solution leaving the ion exchanger column. Preferably, the refractive index is measured as a function of elution time, the integral for the part of the curve deviating from the refractive index of the pure elution agent is determined, and this integral is compared with the value obtained from the calibration measurement.

Alternatively, but less precisely, the extreme value of the refractive index can be measured and thus the content of the surfactant determined after comparison with the calibration curve.

Anionic and cationic surfactants in aqueous solution can be detected, for example, by titration with chamine ^B 1622 (= N-benzyl-N, N-dimethyl-N-4 (1.1.3.3.-tetramethyl-butyl) phenoxy-ethoxyethylammonium chloride) and potentiometric determination of the end point. To this end, replace the sample with a known amount of sodium dodecyl sulfate. is titrated with hyamine and the end point of the titration is determined with an ion-sensitive electrode.

Alternatively, anionic surfactants can also be determined by titration with 1,3-didecyl-2-methylimidazolium chloride. An electrode with an ion-sensitive membrane is inserted as a detector. The electrode potential depends on the concentration of the measuring ions in the solution.

Depending on the result of this personnel expenditure, the associated determination of surfactant completes the process staff with a process solution with one or more complementary components. The process therefore necessitates that at least at the time of the surfactant determination, the service personnel are located at the site of the device. So the process is staff intensive, especially in a multi-shift facility. Documenting the results of quality control and quality assurance requires additional costs.

As a result of the cleaning process, dirt particles are removed from the surfaces into the cleaning solution. Pigment dirt can lead to inorganic bonded carbon loading. Anticorrosive oils., Cooling oils or processing auxiliaries such as cooking grease and / or dissolved or leached organic coatings or grouting materials lead to the loading of the cleaning solution with organically bound carbon. Because this organically bound carbon is mainly found in the form of mineral oils, mineral fats, or oils and fats of animal and vegetable origin, the fatty load of the cleaning solution is often briefly discussed. Such oils and fats are present in the cleaning solution, mostly in emulsified form. Animal or vegetable oils and fats may, at least in part, be hydrolyzed by an alkaline cleaning solution. The hydrolysis products can then also be present in dissolved form in a cleaning solution. Carbon black (TOC) overloads no longer guarantee that the cleaned parts are free from oil and grease to the required extent. Or there may be a risk of oil and grease being applied to the cleaned parts again when they are removed from the cleaning solution. Therefore, it is necessary to keep the load of the cleaning solution with fat below the critical maximum value, which may depend on the continued use of the cleaned parts and on the composition of the cleaning solution. Under high fat loading, the surfactant content of the cleaning solution can either be increased to increase the ability of the cleaning solution to dissolve fats, or the introduction of bath care measures with the aim of reducing the fat load of the cleaning solution. With some preset upper limit on fat load, this is always necessary. In the simplest case, the cleaning solution is discarded in whole or in part and replaced with a new one or supplemented with a fresh cleaning solution. Due to the resulting waste drains as well as the need for fresh water, it is necessary to make sure that the greases and oils from the Cleaning Solution are eliminated and that the cleaning solution is used again in this case after supplementing with the active ingredients. Suitable devices such as separators and membrane filtration devices are known in the art.

It has hitherto been customary to evaluate the cleaning effect of a cleaning solution visually on the basis of cleaning results. The plant's maintenance staff evaluates the cleaning effect and takes the necessary steps, such as replenishing the bath or restoring the bath. This standard procedure nowadays presupposes the presence of fire crews at the required inspection times near the cleaning bath, the shorter the control intervals are desirable, the more burdensome the attendance staff is with the visual assessment.

Depending on the state of the art, it has already been suggested that the individual control parameters of the cleaning baths be determined by program control, that the obtained results be transmitted to a distant target location and that control measurements and / or automated and program-controlled controls be introduced from there. measures for neo kooeli. A procedure for the automatic control and control of the content of surfactants in aqueous process solution is described in German patent application DE 198 14 500, the automatic determination of the dosage of an aqueous cleaning solution with carbon-containing compounds in DE 198 20 800, and the automatic control and control of a cleaning bath with alkalinity determination in DE 198 02 725.7. The present invention is based on these processes, interconnecting them. What can be attributed to each of these determinations is described in detail in the third document. The contents of these three documents are therefore expressly disclosed as such.

It is an object of the present invention to provide control and, preferably, control of the cleaning baths without leaving the maintenance personnel in the place of the cleaning baths.

Preferably, the introduced measuring device should itself be checked and calibrated and would send an alarm message to a remote location in case of malfunction. Furthermore, the feasibility of verifying the functional ability of the measuring device and the measurement results from any remote location should be preferred. Furthermore, it should be possible to interfere with measurements and bath care measures from a remote location. With the help of the goal of remote control set, the staffing need to control and control the cleaning baths will be reduced. In this case, at least two parameters should be determined, from which it will be possible to determine the functional capacity and / or load of the non-dirt cleaner bath. Considering the multiple measurement values introduced, bath care measures will be more purposeful than knowing only the individual measurement quantities.

This task is solvable by a process for the control of a cleaning bath, characterized in that at least two of the following determinations are made programmatically:

i) determination of surfactant content, ii) determination of inorganic and / or organically bound carbon loading, iii) determination of alkalinity, and that

a) Depending on the results of the determinations, additional dosing of supplemental components and / or one or more bath care measures and / or

b) transfer the results of the determinations and / or from the results of the determinations of the derived data to at least one remote target location located in a different space than the device for executing the determinations.

As an example, both surfactant content and organic and / or inorganically bound carbon loading can be determined. Have surfactant content and alkalinity determined. Whether organic and / or inorganically bound carbon loading and alkalinity are determined. Preferably, however, all three parameters are determined to give a complete picture of the condition of the cleaning bath.

How these determinations can be programmatically controlled in detail is described in detail in the documents previously cited. The determinations can be made mainly simultaneously or one after the other.

The results of the determinations can be stored on a data medium. They may, in addition or alternatively, be included as a basis for further calculations. The results of the determinations or the results of further calculations are transmitted to the remote target location (= to some remote location) and stored and / or re-released there on the storage medium if, in the context of the process of the present invention, it is a remote destination or remote location, by this means a place not in close proximity or at least in optical contact with the process solution. For example, a remote location may be a process management system that, as part of the overall process for surface treatment of metal parts, has the task of controlling and controlling the cleaning bath. The remote location may also represent a central control command from which the entire process is controlled and controlled and located, for example, in a space other than the process solution. In any case, a place outside the plant where the treatment bath is located is also considered a remote location. In this way, it is possible for experts to check and control the process solution. lingering outside the plant in which it is located. In this way, it is significantly less necessary to retain professional staff at the site of the cleaning bath.

Suitable data transmitters that can transmit the results of determinations as well as control commands are available according to the state of the art. Issuing the results of determinations or further calculations is understood to mean that they are transferred to a process management system or that they are recognizable to a particular person in the form of a screen display or printed. In this case, the place of display may be. results release the above defined remote location. It is preferred that the results of the individual determinations be stored on a data medium for at least one of the predefined Time intervals so that they can be evaluated in a further procedure, such as quality assurance. The results of the determinations may in no way be directly or as such issued or stored on a data medium. However, they can also be directly attracted as a basis for further calculations, with the results of these further calculations being displayed or saved. For example, a concentration trend and / or a relative change in its content may appear instead of the current content. Does the current content change in% of the desired value or. in% of maximum value.

The aforementioned remote destination may be located at least 500 m from the determination device. In particular, it may also be located outside the plant where the cleaning bath in operation is controlled. Therefore, remote control is provided without the need for service personnel to be in close proximity to the cleaning bath.

In this case, it may be envisaged that the results of the determinations and / or the results of the determinations of the derived data will be transferred to the remote destination automatically whenever new results of the determinations are transmitted and / or the results of the determinations of the derived data. Alternatively, it may be envisaged to transfer the results of the determinations and / or from the results of the determinations of the derived data to the remote target at the request of the remote target.

Individual determinations can be repeated at one of the scheduled time intervals. Alternatively, in the case of software control, the individual determinations may be repeated at a shorter interval, the more the results of the two successive determinations are different. It may also be envisaged that the determination of the second measurement value will occur when the determination of the first measurement value has shown a predetermined critical value or a predetermined change in value between two determinations of that measurement value. The start of measuring determination may therefore depend on the result of determining another measurement.

In other words: the process of the present invention can be carried out as follows. that a programmed control performs another of the determinations i), ii) and iii) the selected determination if the first of the determinations i), ii) and iii) the selected determination produces a result that a predetermined maximum value exceeds or does not reach some predetermined value. set minimum values, or deviate from a predetermined result of this first determination for a predetermined minimum value.

Of course, it can also be envisaged to perform an on-demand determination from a remote destination.

In an embodiment, the process of the invention is characterized by being programmatically controlled

i) carry out the determination of the surfactant content, where:

a) take a sample of a predetermined volume from the aqueous process solution,

b) release the particulate sample if desired,

c) if desired, dilute the sample with water in a predetermined or as a result of a preliminary determination of the ratio obtained,

d) determine the content of surfactants by selective adsorption, electrochemical, chromatographic, grafting on the volatile compounds, distillation (durch Ausstrippen) of these volatile compounds and their detection, or by adding a Weckselwirkung alteration agent (Weckselwirkung) to the sample by electromagnetic radiation t and measuring the variation of this changing effect.

Furthermore, the embodiment of the process according to the invention is characterized in that (ii) the inorganic and / or organically bound carbon loading is determined, programmatically controlled

a) take a sample of a predetermined volume from the aqueous process solution,

b) optionally release and / or homogenize the particulate sample.

c) if desired, dilute the sample with water in a predetermined or as a result of a preliminary determination of the ratio obtained,

d) determine the content of inorganic and / or organically bound carbon in the sample by a known process.

In this case, the content of inorganic carbon (IC), total organic carbon (TOC) or the sum of both (total carbon, TC) in the cleaning solution can be determined by the embodiment of partial step d). In particular, the proportion of lipophilic substances in the purification bath can be captured if an extraction method is included in the determination framework, by which only lipophilic substances are extracted from the cleaning solution and determined in one of the following steps.

A further embodiment of the invention is characterized in that iii) the alkalinity of the Purification bath is determined by an acid-base reaction with an acid, which is program controlled

a) take a sample of the intended volume from the treatment bath,

b) release the particulate sample if desired,

c) select whether free alkalinity and / or total alkalinity should be determined, and

d) the sample titrates or presents the acid with the addition of acid and titrates the sample.

After each partial step a) the sample volume is taken, it is possible to program the control part in the process of the measuring device used. Preferably, the sample volume is variable from a remote location. Furthermore, the control program can be interpreted so that the sample volume used depends on the result of the previous measurement. For example, the sample volume can be selected as large as possible, the smaller the content of the specified substances in the treatment bath. The accuracy of the determination can thus be optimized.

It may be desirable during sample collection and measurement to allow the sample to release solids after each optional partial step b). This is not necessary with a clean solution that is only slightly laden with particulate matter. However, if the solids content is too high, the valves of the measuring device may become clogged and the sensors may become contaminated. It is therefore advisable to remove solids from the sample. This can be done automatically by filtering or also by using a cyclone or centrifuge.

Prior to determining the selected parameters, it is advisable to dilute the sample with water in a previously specified or as a result of a preliminary determination of the determined ratio. Partial step d) is followed by the determination by various methods, which will be explained in more detail below.

In the simplest case, the process according to the invention works by repeating each determination at a predetermined time interval. The predetermined time interval follows the requirements of the process solution manager and can be any time interval in the range of minutes to several days. For quality assurance, it is preferable that a predetermined time interval lies, for example, in the range of 5 minutes to 2 hours. For example, a measurement can be made every 15 minutes.

The process of the invention may in any case also be carried out by repeating each determination at this shorter time interval, as much as possible the results of the two successive determinations differ. The control system of the process according to the invention can therefore decide for itself whether the intervals between determinations need to be shortened or extended. Of course, it is necessary to give the control system a preliminary indication of the differences between the results of two successive determinations and to select a specific time interval.

In this case, it is not compulsory that 2 or 3 different definitions i), ii) and iii) are always implemented in this order one after the other. On the contrary, one determination can be made more often than any other. This will be accessed as soon as the orax shows that some parameter changes faster than the other. For example, the surfactant content is more often determined than the alkalinity. Whether the device is programmed to become dependent on the result of one determination is to be started with another determination. For example, we can predict alkalinity determination only when the carbon content of the treatment bath exceeds a predetermined limit value. Is it possible to determine alkalinity only after the surfactant content in the treatment bath falls below the predetermined lower limit. For example, we can choose if only the surfactant components or the builder components (Builder components) are added to the cleaning baths.

Further, the process of the invention can be carried out by making determinations at any time on the basis of an external command. For example, immediate control of the surfactant content, alkalinity and / or fat load of the cleaning solution can be undertaken if quality problems are identified in the subsequent process steps. Measurement of the selected determination values follows a time-controlled (at specified time intervals) or event-controlled (if changes are detected or also an external command).

i) Determination of surfactant content

The process can be interpreted as meaning that the surfactants whose content in the process solution must be determined are non-ionic surfactants. To determine these, proceed by adding reagent in partial step d). which changes the exchange action of the sample by electromagnetic radiation in proportion to the content of non-ionic surfactants and measures the change in this exchange action.

For example, the reagent may be a complex of two substances A and B, with non-ionic surfactants displacing substance B from the complex with substance A, thereby changing the color or fluorescence property of substance B. For example, substance B may be a fluorescent substance or dye that can become a complex with, for example, dextran or starch as an example of substance A. As a component of complex B, substance B has certain color or fluorescence properties, when these are ejected from the complex, these properties change. By measuring light absorption or fluorescence, it is then possible to detect which portion of substance B is not presented in the form of a complex with A. In this case, substance A is selected by removing substance B from the complex with the addition of non-ionic surfactants and instead forming a complex with non-ionic surfactants . In this case, the amount from complex A of the displaced substance B is proportional to the amount of non-ionic surfactants added. The amount of B-induced change in light absorption or fluorescence can be deduced from the amount of non-ionic surfactants added.

For example, it may be inserted as a reagent a salt of a cationic dye with tetraphenylboratanions. Non-ionic surfactants can remove the dye from this salt after the salt is modified by the addition of barium ions in the cation complex with barium. This method, by which non-ionic surfactants are converted into cation-charged complexes, thereby making a cation-responsive reaction possible, is also referred to in the literature as activation of non-ionic surfactants. The procedure is described, for example, in Vvtras K .. Dvorakova V. and Zeeman I. (1989) Analvst 114. p. 1435 ff. The amount of dye cationscecre released from the reagent is proportional to the amount of non-ionic surfactants available. if the absorption spectrum of the dye changes upon this release, the released amount of the dye can be determined by photometric measurement of a suitable absorption band.

This method of determination can be simplified by inserting a cationic dye salt as a reagent soluble only in a water-immiscible organic solvent, while the released dye is only water-soluble and leads to the coloration of the aqueous phase. A reverse process is also understandable: a water-soluble salt of an organic colorant is inserted, leaving the released colorant soluble only in the organic phase. By releasing the dye in exchange for non-ionic surfactants and by extracting the released dye in each of the second phases, it is easy to determine photometrically.

This determination process is also suitable for the determination of cationic surfactants. As these are positively charged, activation of barium cations as described above becomes unnecessary.

Further, the reagent may be a substance that forms with an anionic surfactants a complex having other color or fluorescence properties than the free reagent. For example, the reagent may be colorless in the optical region, while its complex with non-ionic surfactants will absorb electromagnetic oscillations in the optical region, thus having a color. Or the maximum of light absorption, that is, the color, of the unbound reagent may differ from the absorption of a complex having non-ionic surfactants. However, the reagent may also exhibit certain fluorescence properties that change when complexed with non-ionic surfactants. For example, a free regent can fluoresce. while the formation of a complex with non-ionic surfactants fluoresces. In any case, by measuring light absorption at a given predetermined wavelength or fluorescent radiation, the concentration of the reagent complex and non-ionic surfactants can be determined by itself.

Preferably, in a partial step d), a reagent is added which forms with a non-ionic surfactant a complex that can be extracted in not every proportion with a water miscible organic solvent. Then, the complex is extracted from non-ionic surfactants and added reagent in water, not in any ratio of miscible organic solvent. This can be achieved by intensive mixing of the two phases, for example by shaking or preferentially whipping. After this extraction step, the mixing of the two phases is completed so that one phase separation enters one aqueous and one organic phase. If desired, the completeness of phase separation can be controlled by suitable methods such as the determination of electrical conductivity or quality measurements by light absorption or light scattering.

This is followed by a true measurement of the content of non-ionic oxides. Here, the organic phases containing the non-ionic surfactant complex and the reagent added are exposed, to electromagnetic radiation that can enter the organic phase dissolved complex in the exchange action. For example, visible or ultraviolet radiation can be introduced as electromagnetic radiation, the absorption of which is determined by a complex of non-ionic surfactants and added reagent. It is also conceivable, for example, to insert a reagent whose complex with non-ionic surfactants gives a characteristic signal when measuring nuclear resonance or electron paramagnetic resonance. The strength of the signal, expressed as attenuation of the electromagnetic oscillation in the corresponding frequency band (absorption), can become correlative with the concentration of the complex. Instead of the absorption effect, the emission effect can be drawn to determine the concentration. For example, a reagent whose complex is absorbed by a non-ionic surfactant in an organic solvent may be selected to electromagnetic radiation of one particular wavelength, and therefore emit electromagnetic radiation of a larger wavelength, whose intensity is measured. An example of this is the measurement of fluorescent radiation when irradiating a sample with visible or ultraviolet light.

In principle, a mixture of the alternating action of an organic phase with electromagnetic radiation, immediately after completion of the phase separation, may be supplied to the same vessel in which the phase separation is carried out. Depending on the measurement method used to determine the alternating action of an organic phase by electromagnetic radiation, it should certainly be considered preferable to remove the organic phase or part thereof from there and supply the correct measuring apparatus through a conductor. Thus, it is especially possible to provide for measuring a suitable cuvette. Therefore, there is a preferred embodiment of the invention in that in a partial step f) the organic phase is separated from the aqueous phase and fed to the measuring apparatus. For this separation of the organic phase, it is particularly advisable if the water-immiscible organic solvent in each ratio is a halogen-containing solvent with a density higher than water. After the phase separation is carried out, the organic phase is located in the lower part of the container and can be removed from below.

Halogen-containing solvents include, for example, dichloromethane or higher boiling point halogen hydrocarbons, in particular fluorochlorine hydrocarbons such as trifluorotrichloroethane. These solvents must be disposed of in accordance with local regulations after use. As this may be costly, we are offered a solution to refinish used solvents, such as activated carbon and / or distillation, and use them in the measurement process.

In a preferred embodiment of the invention, an agent that causes a color reaction in the organic phase with a non-ionic surfactant is added as the reagent. As an alternating effect of the organic phase with electromagnetic radiation, light absorption at a predetermined wavelength can be measured. A conventional photometer is suitable for this. For example, tetrabromophenolphthaleinethyl ester may be used as a color reagent. In this case, a sample of the aqueous process fluid having a buffer system for pH value in the range 7 must be moved. Such a buffer system may, for example, be an aqueous solution of dihydrogen phosphates and hydrogen phosphates. Preferably, the amount of buffer solution is substantially greater than the sample amount of the surfactant-containing process solution.

When using tetrabromophenolphthaleinethyl ester as a color reagent, the measurement of light absorption after a partial step g) is carried out, preferably at a wavelength of 610 nm.

According to a preferred embodiment, the use of 3,5,5,5tetrabromof enolf taleinethyl ester as a color reagent may be followed by the determination of the content of non-ionic surfactants as follows: prepare an indicator solution containing 100 mg of 3,5,5,5-tetrabromophenolphthaleinethyl ester in 100 ml of ethanol. Further, a buffer solution is prepared by mixing 200 ml of commercially available buffer solution for pH 7 (potassium dihydroaenphosphate / disodium hydroaenphosphate) and 500 ml of trimolar potassium chloride solution with 1000 ml of water.

18 ml of buffer solution are prepared in a suitable container to carry out the determination. To this was added 2 ml of indicator solution. To this was added 50 μΐ of the sample solution. Stir the total solution for about 3 minutes and then add 20 ml of dichloromethane. Then the pan is stirred vigorously for about 1 minute. It then waits for phase separation, which may take about 20 minutes. The organic phase is then taken off and measured in a photometer at a wavelength of 610 nm. For example, a 10 mm cuvette is suitable for analysis. The surfactant content of the sample solution is determined using a calibration curve.

if the surfactant content is so small that the determination is uncertain, the volume used to measure the sample used may be increased. If the surfactant content is so high that the absorption of light exceeds 0.9, it is recommended that the sample be diluted before measurement.

Irrespective of the method chosen, the calibration between the strength of the measurement signal and the concentration of non-ionic surfactants must be produced and stored by prior calibration with the surfactant solutions of known concentration. When measuring light absorption, calibration using suitable colored glasses may follow. Alternatively to the pre-calibration, the addition of the surfactant reagent to the complex at a known concentration or by repeated magnification and repeated measurement of the alternating action by electromagnetic radiation may lead to the conclusion of the surfactant content in the sample.

As an alternative to determining the exchange of the action of a non-ionic surfactant bound or non-ionic surfactant complex with electromagnetic radiation, the content of non-ionic surfactants can be determined chromatographically. Therefore, any oils and greases present are preferably removed from the sample first. This can be done, for example, by some absorption agent. A sample containing ionic surfactants, where appropriate, is then placed into an anionic and / or cation exchange column, which is preferably carried out similarly to a high pressure liquid chromatography column. The concentration of non-ionic surfactants in the ionic surfactants of the released solution leaving the exchange column is preferably determined by the refractive index. Quantitative evaluation is carried out, preferably by the external standards method. The measurement is performed by comparing the brown pure solvent from the comparison cell and the solvent with the analyte substance from the measuring cell of the detector. Water or a mixture of water and methanol are suitable as solvent.

Prior to the start of the measurement series, an HPLC-form ion exchange system must be used. calibrate and rinse the detector cell for 20 minutes with the solvent. For calibration, differently concentrated solutions of the determined non-ionic surfactants are used. The calibration and sample solution should be degassed in an ultrasonic bath for approximately 5 minutes before being injected into the HPLC system. Defined IU degassing is important because of the sensitivity of the refractive index detection to different solution qualities.

if a sample solution is translated before applying methanol to an HPLC-like ion exchanger column, insoluble salts may precipitate. These should be filtered into a HPLC-like system before dosing the sample with a micro filter.

This method is known for the off-line determination of non-sulfated particles in organic sulfates or sulfonates (DIN EN 8799).

Furthermore, the following procedure is suitable for the determination of non-ionic surfactants: the cleavage of non-ionic surfactants by halogenation, preferably with iodine, under the formation of volatile alkyl halides, preferably alkyldiiodides. By blowing the gas stream into the sample, it is distilled off. The stript man aus is extracted by volatile alkyl halides and is detected in a suitable detector, for example the Electron Capture Detector is suitable. This procedure is known as the laboratory method for determining the characteristics of fatty alcoholetoxylates (DGF Single Method (Einheitsmethode) H-3 17 (1994)).

Surfactants may also be anionic surfactants. Their content in the sample solution is determined in partial step d) preferably electrochemically. Therefore, anionic surfactants are titrated with suitable reagents, and the titration is performed by varying the electrical potential of the suitable measuring electrode.

For example, this is done by adjusting the pH of the sample in the range of 3 to 4, preferably at about 3.5, titrating the sample with a titration reagent in the presence of an ion-sensitive membrane electrode and measuring the electrode potential change. The sensitivity of this method can be increased by replacing the sample with alcohol of 1 to 3 C atoms, preferably methanol. Preferably, 1,3-didecyl-2methylimidazolium chloride is suitable as the titration reagent. An ion-sensitive membrane electrode, preferably a PVC membrane, serves as the measuring electrode. Such an electrode is known as a High Sense Electrode. A preferred silver electrode is inserted as the reference electrode. The potential occurs by the most specific exchange action between the ion-carrying ionic carrier (Ionencarrier) in the PVC membrane and the determining ions in the measuring solution. This exchange action leads to a balanced reaction to the transition of the measuring ions from the measuring solution to the membrane, and thus to the formation of the difference of electrical potentials at the phase boundary of the measuring solution / membrane. This potential difference can be measured against the reference electrode potentiometrically (no current). The extent of ion transfer from the measurement solution to the membrane depends on the concentration. The relationship between the concentration of measuring ions and the electrical potential can theoretically be described by the Nernst equation. Due to possible interference, it is preferable to determine the relationship between the electrode potential and the concentration of the measuring ions by means of a calibration solution.

In addition to anionic surfactants, cationic surfactants can also be determined in a controlled measuring solution. For this, a method that is also suitable for the determination of anionic surfactants is used. The electrochemical determination is also carried out following this procedure. A predefined amount of sodium dodecyl sulfate is introduced into the sample. titrate the sample with chiamine (N-benzyl-N, N-dimethyl-N-4 (1.1.3.3.-tetramethylbutyl) phenoxy-ethoxyethylammonium chloride) and determine the titration end point with an ion-sensitive electrode.

Apart from the above, the process is suitable for determining the surfactant process whereby surfactants are absorbed in a suitable plane and the effects explained by the application of surfactants on the plate are measured. As the coating of the surfactant plates below the saturation limit in proportion to the surfactant content, the calibration is concluded from the changes of the coated plates back to the surfactant content in the solution.

can be adjusted as can be modeled by the appropriate surfactant property

For example, surfactants on the quartz vibrator plane can be absorbed and changes in the oscillation frequency of the quartz vibrator can be measured. A further process is that the surfactants are absorbed into the light guide conductor surfaces, if necessary, when necessary. This leads to a change in the refractive index in the transition of light from the light conductor to the surrounding medium, which is noticeable due to the electrical conductivity of the light conductor. Depending on the refractive index, the light in the light conductor is differently diminished or does not appear at all at the end of the light conductor. By comparing the output light intensity at the end of the light conductor with the initially introduced one, the degree of coating of the light conductor surface by the surfactants and thus the surfactant content in the surrounding medium can be determined. The total repulsion fracture occurs at a certain threshold value of the surfactant content, which can also be drawn to determine the characteristics of the surfactant content in the process solution.

ii) Determination of Carbon Load

Determination of inorganic and / or organically bound carbon loading can be carried out as described in more detail in US patent application H 3268. It is recommended to homogenize the sample, for example, with vigorous stirring, before determining the parameter. This results in a uniform and fine distribution of organic impurities in the presence of coarse oil or fat droplets.

If necessary, in a partial step c), the sample is diluted to some extent with water. This ratio may be fixed in advance, but variable from some remote location. However, the dilution ratio may also depend on the result of the previously determined content of inorganic and / or organically bound carbon. This will ensure that the carbon content of the sample solution is located in an area that permits optimal determination by the method chosen.

In partial step d), inorganic and / or organically bound carbon can be determined, for example, as follows. to be guided through C0 ₂ and the resulting C0 ₂ quantified.

Carbon transfer to C0 ₂ by oxidation can be effected by combustion at elevated temperature in the gas phase. The elevated combustion temperature preferably lies above about 600 ° C, for example at about 680 ° C. Preferably, combustion with air or oxygen in the reaction tube is carried out using a catalyst. For example, the noble metal oxides or other metal oxides such as vanadates, vanadium oxides, oxides of chromium, manganese or iron may be considered as catalysts. Even alumina-colored platinum or palladium can be used as a catalyst. After this process directly C0 ₂ containing combustion gas, the content of C0 ₂ can be determined as hereinafter described.

Alternatively to the combustion in the gas phase, the carbon transition to CO _{2 can} also be carried out by a wet chemical process. In doing so, the carbon of the sample is oxidized by a strong chemical oxidizing agent such as carbon peroxide or peroxodisulfate. This wet chemical oxidation reaction can be accelerated as desired by a catalyst of the aforementioned species and / or by UV irradiation. In this case, it is preferable to extract the resulting C0 ₂ with a gas stream from a, if desired, acidified sample, which can be quantified. Carbonates or C0 ₂ bound carbon can thus also be recorded.

Irrespective of the method by which gaseous C0 ₂ is obtained, it can be quantified by one of the following methods. For a known sample quantity, the content of inorganic and / or inorganically bound carbon in the cleaning solution can be calculated from it. Alternatively, a predetermined conversion factor results in the determination of a fat load per one scrubber when no inorganically bound carbon is present or has been previously removed.

To determine the content of C0 ₂ in the gas stream obtained, the methods known in the art will be different at the present development stage. For example, it is possible to guide the gases through the absorption solution and, for example, to measure the weight gain of the absorption solution. For example, an aqueous solution of potassium hydroxide that absorbs C0 ₂ is suitable. formed by potassium carbonate. Alternatively to the determination of Drirast weight, the change in the electrical conductivity of the absorbent solution or its residual alkalinity after absorption of C0 ₂ may be determined.

The resulting C0 ₂ can also be absorbed in a suitable rigid body whose weight gain is measured. Sodium asbestos is suitable for this. Of course, both the absorbent solution and the solid absorber must be replaced if they are exhausted and can no longer bind C0 ₂ .

However, for an automated process, it is easier to quantify the C0 ₂ content of a gas by measuring infrared absorption. The determination of infrared absorption can be made, for example, at a wavelength of 4.26 μm, which corresponds to a wave number of 2349 cm ¹ . Apparatuses used to perform sample combustion and infrared absorption measurements are known in the art today. For example, the Shimadzu TOC system should be listed.

For photometric determination of the content of C0 ₂ in the combustion gas or in the gas ejected from the sample, not only the dispersion-operated infrared spectrometer but also the non-dispersion photometer are considered. These are also known as NDIR appliances. Such apparatus is described, for example, in DE-A-44 05

881.

This method of determination also covers the proportion of carbon resulting from the deliberately added active substance to the cleaning solution. For example, they should be called surfactants. organic corrosion inhibitors and organic complexing agents. Their content in the cleaning solution is known within the tolerance limits or can be determined separately. The proportion of organically bound carbon resulting from these substances may therefore be deducted from the result of the determination. In practice, it is not necessarily necessary to consider carbon in the form of active ingredients of the carbon present in order to determine carbon. On the contrary, it is often enough to set an upper limit for the carbon content of the treatment bath, which already takes into account the substance content. The carbon determination then determines if there is a carbon load below or above this ceiling.

Alternatively, the proportion of organically bound carbon in the form of lipophilic substances can be determined by extracting the lipophilic substances with water and not in any ratio a miscible organic solvent. After evaporation of the solvent, lipophilic substances remain and can be determined gravimetrically. Preferably, however, the infrared absorption of lipophilic substances in the extract is determined photometrically. Not all miscible organic solvents, especially haloaenylated hydrocarbons, come into play with water. A preferred example of this is 1,1,2-trichlorotrifluoroethane. This IU determination method used in DIN 38409, Part 17. In contrast to this method, the proportion of lipophilic substances in the sample is by no means determined gravimetrically after evaporation of the organic solvent, but photometrically in the organic solvent. The quantitative determination is carried out preferably as in DIN 38409, Part 18. by measuring the infrared absorption of lipophilic substances in the extract at the characteristic fluctuation frequency of the CH ₂ group. It is advisable to use an organic extraction solvent that does not contain any CH 2 groups alone. For example, an infrared absorber at 3.42 µm (2924 cm -1) may be used for this photometric determination. This includes all oranic substances having CH2 groups and which can be extracted into an organic solvent. Particularly these are surfactants in the cleaning solution, if their proportion cannot be combined together, they are eliminated by the alternative method of determination and deducted from the total result.

If necessary, the partition coefficient of surfactants between the cleaning solution and with water, not in any proportion of miscible organic solvent, must be determined beforehand. In practice, however, it may be sufficient to determine the maximum value of the permissible loading of the cleaning solution with lipophilic substances which in addition take into account the percentage of surfactants. If this maximum value is exceeded, bath care measures must be activated.

Within this method, it is advisable to calibrate an infrared spectrometer with a known amount of lipophilic substances. For example, a solution of 400 500 mg methyl palmitate in 100 ml of 1,1,2-trichlorofluoroethane is suitable as a calibration solution. This calibration solution serves at the same time as the functional control of the infrared photometer.

This is preferably done by replacing the sample of the cleaning solution first with the phosphoric acid magnesium sulfate solution. This solution is prepared by dissolving 220 g of crystalline magnesium sulphate and 125 ml of 85 wt% phosphoric acid in deionized water and supplementing this solution with deionized water up to 1000 g. The sample solution is mixed with approximately 20 ml of phosphoric acid magnesium sulfate solution. Then 50 ml of water is added in each ratio of miscible organic solvent, preferably 1,1,2triclortrifluoroethane. The aqueous and oranic phases are mixed, phase separation is carried out and organic phases are isolated. Preferably, the organic phases are washed again with phosphoric acid magnesium sulfate solution, again separating the phases and removing the organic phases. These are translated into a measuring cell and infrared absorption is measured at the CH ₂ band fluctuation spectrum. For example, a flint glass cuvette with a layer thickness of 1 mm is suitable as a measuring cuvette. From the comparison with the calibration curve, which also contains the Blindwert value of the photometer. the content of lipophilic substances in the sample can be determined on the basis of infrared absorption.

In carrying out the process of the invention, it is desirable to capture both inorganically bound and organically bound carbon (TOC). This is, for example, the case when the sample is ignited to determine the carbon content. Dissolved C0 ₂ or carbon present in the form of carbonates is also captured if the carbonates at the selected combustion temperature split C0 ₂ . if inorganic bound carbon is not captured in this case, it can be removed so that the sample is acidified and C0 ₂ is produced with gas such as air or nitrogen. This may be desirable if only the fat load of the scrubber is to be determined specifically. When determining the carbon content of a lipophilic substance by the extraction method described above, inorganic bound carbon is not automatically captured next to it.

It is also possible to remove volatile organic compounds before performing partial step d) from the sample by blowing it with gas such as air or nitrogen. For example, volatile solvents can be removed before carbon is determined.

iii) Determination of alkalinity

The determination of alkalinity can be approached as described in German patent application DE 198 02 725.7.

For this process, a specific partial step c) is to choose from the variants whether free alkalinity and / or total alkalinity is determined. This may be fixed in the course of the program. For example, both free alkalinity and total alkalinity may be determined in a determination cycle. The program may also decide that one of these two values is more often specified than the other. This is the case, for example, when we have determined from one of the preceding determinations that one of the two values changes faster than the other. Of course, the choice between whether alkalinity or total alkalinity is determined may also be made by an external command. The term external command means that the automated determination process is accessed either by a parent process system or manually via a data carrier.

The concepts of free alkalinity and total alkalinity ”are not uniquely defined and are used differently by different users. For example, certain pH values can be defined before being titrated to determine either free alkalinity or total alkalinity, for example Ph = 8 for free alkalinity and pH = 4.5 for total alkalinity. These pre-selected pH values must be given to the control system for the automatic determination process. Alternatively to the determination of the pH value, the transition points of certain indicators can also be selected to determine the free and total alkalinity. Alternatively, we can select the breakpoints in the pH curve and define them as equivalent points for free alkalinity or total alkalinity.

An acid-base reaction with an acid is used to determine the true alkalinity in partial step d). Preferably, a strong acid is selected for this. The sample may be titrated by adding acid to the predefined criteria for free alkalinity or total alkalinity. Alternatively, acid may be provided and titrated with the sample.

Different sensors are suitable for monitoring the acid-base reaction of the cleaning solution with the titration of the acid used. Depending on the current state of the art, a glass electrode is preferably used on the pH, for example, the voltage signal that

The use of such an electrode is particularly easy in terms of devices and therefore preferred.

a sensitive electrode such as that gives the dH dependent can continue to evaluate.

However, to monitor the acid-base reaction after partial step d), an indicator whose pH-dependent exchange action is measured by electromagnetic radiation may also be used. For example, such an indicator may be a classic color indicator whose color leap is photometrically measured. Alternatively, an optical sensor may be used. For example, it is a layer of inorganic or organic polymer with a fixed color substance, which changes its color at a certain pH value. The color leap is based on the classic color indicator on this one. that hydrogen or hydrogen oxide ions that can diffuse into the layer react with the molecules of the colored substance. The change in the optical properties of the layers can be determined photometrically. Alternatively, films can be used as, for example, organic polymers whose refractive index changes as a function of pH. if, for example, a light conductor with such a polymer is coated, it can be achieved that on one side of the refractive index threshold the total reflection enters the light conductor so that the light beam is forward. On the other hand, the threshold value of the refractive index no longer reflects completely by leaving the light beam leaving the light conductor. At the end of the light guide, we can detect whether or not the light will propagate through the light guide. Such a device is known as an optrode.

In addition, inorganic or organic solids may be used as sensors whose electrical properties vary with the pH of the surrounding solution. For example, an ionic conductor whose conductivity depends on the concentration of H ⁺ ions or ΟΗ'-ions may be used. By measuring the conductivity of the sensors at direct or alternating current, we can deduce the pH value of the surrounding medium.

Ka libri r ani e / con trol mer i t ve

Preferably, the process of the invention is carried out as follows. that the measuring devices used for the individual determinations are themselves controlled and, if necessary, calibrated. It may be envisaged that, after a predetermined time interval or a predetermined number of determinations, or on the basis of an external command, the functional capacity of the measuring device used shall be checked by means of control measurements of one or more standard solutions. A standard solution with known values of the specified parameters is measured for verification. This check is closest to the true state if a standard cleaning solution is used as standard solution, the composition of which is preferably closest to the cleaning solution tested.

if the measuring device determines a value which deviates from the desired minimum value from the desired value during the control measurement of the standard solution, the measuring device shall send an alarm message locally or preferably at a remote location. In doing so, the alarm message with the control device of the measuring device may contain the selected proposal to the parent system for managing the forwarding process.

Control of the sensors used is a central test point for the functional capacity of the alkalinity measuring device. For example, this may be a pH-sensitive electrode, especially a glass electrode. Using the buffer solution as a standard solution, it is possible to check that the electrodes give the expected voltage and are triggered within the required time, with their slope (= voltage change as a function of pH change) lying in the desired range, if not so that the measuring device is transmitted locally or preferably an alarm message to a remote location. An alarm message from the control program of the measuring device or from the parent process management system may contain the selected proposal for intervention. For example, it may be suggested that the electrode should be cleaned or replaced.

The method of the invention may also provide for the control measurement of one or more standard solutions to check the functional ability of the measuring device used, if the results of two successive measurements differ for a predetermined value. This can confirm that the detected deviations of the contents of the cleaning bath are realistic and require bath care measures or that the deviations due to a fault in the measuring system are only simulated.

Depending on the results of the verification of the measuring device used, during the current and previous control measurement of the determination made, it may be provided with a status symbol indicating the reliability of these determinations, if, for example, two consecutive control measurements for checking the measuring apparatus used have shown that it is working properly, may equip decisions with a status sign OK, if the results of control measurements differ for a predetermined minimum value, for example, we can mark at a certain time the next determination with a status sign in doubt.

In addition, it may be envisaged that, depending on the results of the verification of the measuring device used, the automatic determination of the measuring quantities will continue and / or take one or more of the following actions: analysis of the detected deviations, correction of the measuring device, completion of the determination of the subject measuring value, sending a status message or alarm. signal to the parent process control system or control device, ie to a remote location. The measuring device may therefore, if desired, decide on the basis of predefined criteria, if it is functionally capable of carrying out all determinations, or if deviations requiring manual interference have been identified.

Preferably, according to the invented method, the measuring system used is exposed so as to automatically control the full states and / or consumption of the reagent and solvent used, as well as the rinsing solutions, and, when exceeding a predetermined minimum filling state, emits a warning message. In this way, the measuring device can be prevented from becoming functionally incompetent because it lacks the required chemicals. Full-state control can be performed by known methods. For example, chemical containers may be placed on a balance that registers the respective weight of the chemicals. Have a float inserted. Alternatively, the minimum charge state can be checked with a conductive electrode immersed in a chemical container. The alert message transmitted from the measuring device is preferably transmitted to a remote location so that appropriate action can be taken from there. Generally, the process of the invention preferably provides that the results of determinations and / or control measurements and / or calibration and / or command are transmitted to a remote location. Thus, supervisory staff who do not have to be at the site of the scrub bath are promptly informed of the current alkali content. Depending on the results of the determinations and control measurements, both the automatic process control system and the manual interference can determine the necessary corrective measures.

Within the process of the invention, it may be envisaged that for each of the determinations i), ii) and iii), a determination is made after a predetermined time interval or a predetermined number of determinations or on the basis of a command from a remote target site with a control measurement of one or more of standard solutions checks the functional ability of the measuring instrument used and transmits the result of the test to a distant target. Furthermore, an appropriate verification of the functional ability of the measuring device used may be introduced if the results of two consecutive determinations differ by a predetermined value. Also, the result of this verification is preferably transferred to a remote target location. Depending on the result of the verification of the measuring device used, during the current and previous control measurement, the determined determinations of the respective measuring value may be provided with a status symbol indicating the reliability of this determination.

In the process of the invention, it may further be provided that, depending on the results of one or more of the determinations i), ii) and iii), an additional dosage of supplementary components and / or one or more care measures is introduced from the selected target site. baths. Alternatively or in addition, it may be envisaged that, depending on the outcome of one or more determinations (i), (ii) or (iii), determinations selected or program-controlled determinations, additional dosing of supplemental components and / or one or more bath care measures.

Further, it may be contemplated in the process of the invention to introduce program-controlled supplemental dosing of supplemental components and / or one or more bath care measures if predefined ratios of the results of at least two of the determinations i), ii) or iii) are selected determination. Therefore, the control program is preferred for the process of determining the relationships between the results of the individual determinations i), ii) or iii), at the onset of which additional dosing of supplemental components and / or bath care measures is introduced. Therefore, a decision is made not on the basis of individual measurement values, but at least two measurement values of different bath parameters. In doing so, the relationships under which action is taken may vary from a remote location to take into account, for example, operational experience. For example, it may be envisaged that a measure be taken to reduce the fat load of the cleaning bath (complete or partial restoration of the bath, removal of grease and / or oils from the bath by separators and / or by membrane filtration procedures) if the content of organically bound carbon exceeds on one hand predetermined maximum content and, on the other hand, the surfactant content decreases below the preset minimum content. Is there a set maximum value of the surfactant content and fat load above which the bath care measures are automatically imposed.

Depending on the measurement value obtained or the measurement change detected, one or more of the following corrective measures may be applied:

Corrections and care measures for copa1i

The simplest corrective action is to overrun a pre-set maximum value of inorganically and / or organically bound carbon, or to an external command, a device that dispenses one or more complementary components (solution or powder) in a cleaning bath. This is done automatically, for example, by adding a certain amount of supplementing solution or supplementing powder to the cleaning bath, depending on the carbon content determined. In doing so, it may vary the size of the additional Dorcia alone or, in the case of a fixed predetermined additional portion, vary the time intervals between each addition. This can be done, for example, by a metering pump or by weight control. In the process of the invention, therefore, it is also contemplated that, in certain deviations from the desired values (especially if control measurement determines the functional capability of the measuring device), a certain amount of the supplementary component in the treatment bath is additionally dosed. In addition, it may be envisaged that bath supplementation measures should be taken after a predetermined minimum change in carbon content is identified. Further, this additional dosage can also be performed on the basis of an external command, such as from a remote location, regardless of the actual carbon content. Additional dosing such as surfactants increases the carbon content of the cleaning solution. The next determination of carbon content should be duly taken into account, which is done automatically. The addition of surfactant increases the oil and grease mixing capacity of the cleaning bath. The permissible maximum value of the carbon load must be raised accordingly, exceeded by the following bath care measure. This can be predicted automatically in the control program.

Instead of supplementary dosing of bath components such as surfactants or exceeding a predetermined maximum content of inorganic and / or organically bound carbon, bath care measures may be introduced to reduce the content of inorganic and / or organically bound carbon in the cleaning solution. Such bath care measures are primarily intended to reduce the fat and oil content of the cleaning solution. In the simplest case, this happens by completely or partially draining the cleaning solution and replacing it with a fresh one. However, it is more economical to remove oils and greases from the purification bath with the help of known measures in the present state of the art, such as separation by separators or separation by membrane filtration. Since surfactants are at least partially removed in these processes, the cleaning solution must be adequately supplemented. The introduction of these measures may not only depend on the absolute carbon content of the solution, but also on the predetermined change in carbon content.

For the control and control of the surfactant content and / or the alkalinity, it may be envisaged that a device dosing one or more complementary components of the cleaning bath may be activated by lowering the pre-set minimum content value or by an external command. For example, a complementary solution containing all the active ingredients of the cleaning solution in the right amount is suitable as a complementary component. In addition to the controlled substances, the additive solution may contain other active ingredients of the cleaning solution, such as surfactants, substance-forming agents, alkalis, complexing agents and corrosion inhibitors. Alternatively, the surfactant solution may contain only surfactants or only alkalis, while other active ingredients of the cleaning bath may be further dosed, if necessary on the basis of separate determinations.

In this way, the sizes of the extra portions themselves, or with fixed predetermined incremental portions, can vary the intervals between the individual additions. This can be done, for example, with metering pumps or with gravity control. Thus, for the first time in the process of the invention, it is envisaged that, at certain deviations from the desired values (especially if the functional ability of the measuring device is determined by control measurement), a certain amount of the supplementary component of the process solution is dosed. Secondly, this additional dosage may also be performed on the basis of an external command, such as from a remote location, regardless of the current content of surfactants and / or alkalis.

In a further embodiment of the invention, the process solution is supplemented, depending on the permeability, with a predetermined amount of the supplementary component per unit of flow. For example, it may be possible to determine, in the car body cleaning bath, what quantities of complementary components per cleaned bodywork should be added. The invention relates to the control of the content of surfactants or. alkali is used for this. that the result of these predefined additives is controlled and documented and that a more constant mode of operation of the scrubber is achieved by the additional fine-dosing, including, if necessary, by excluding the basic dosage. Quality fluctuations will thus be reduced.

Of course, the process of the invention provides for the availability of suitable apparatus. It contains control preferred computer control that controls the measurement course in a time and / or event dependent manner. It must further contain the necessary reagent vessels, piping, valves, metering and measuring devices, etc. for controlling and measuring sample currents. The materials must be adapted for their intended use, for example they must be made of stainless steel and / or plastic. The control electronics of measuring devices must have appropriate input - output interfaces in order to establish communication with the remote site.

The process according to the invention allows to check the contents of the cleaning baths on site and to introduce predefined corrective measures without manual intervention. This increases process reliability and achieves consistently reliable cleaning results. Deviations from the desired values can be detected in a timely manner and automatically or manually corrected before the cleaning result deteriorates. In addition, the measurement data may be preferably transmitted to a remote location so that the cleaning or bathing staff is kept up to date on the status of the cleaning bath, even if it is not in its immediate vicinity. The number of staff for controlling and controlling the cleaning bath can thus be significantly reduced. Documentation in the process of data input according to the invention meets the requirements of modern quality assurance. Consumption of chemicals can become easily documented and optimized.

Claims (17)

A method for controlling the cleaning baths, characterized in that at the site of the cleaning bath, one or more samples are automatically programmatically controlled from the cleaning bath and at least two of the following determinations are made: i) determination of surfactant content, ii) determination of inorganic and / or organically bound carbon loading, iii) determination of alkalinity, and that a) Depending on the results of the determinations, additional dosing of supplemental components and / or one or more bath care measures and / or b) transfer the results of the determinations and / or from the results of the determinations of the derived data to at least one remote target location located in a different space than the device for performing the determinations. Method according to claim 1, characterized in that the remote target site is located at least 500 m away from the device for carrying out determinations. Method according to one of both claims 1 and 2, characterized in that the results of the determinations and / or the results of the determinations of the derived data are automatically transferred to the remote target location whenever new results of the determinations and / or the results of the determinations are transmitted. the data obtained. The method according to one of both claims 1 and 2, characterized in that the results of the determinations and / or the results of the determinations of the derived data are transmitted to the remote target site upon request from the remote target site. Method according to one or more of Claims 1 to 4, characterized in that the individual determinations are repeated at predetermined time intervals. Method according to one or more of Claims 1 to 4, characterized in that the individual determinations are repeated at shorter intervals, to the extent that the results of the two successively subsequent determinations differ. Method according to one or more of Claims 1 to 4, characterized in that on-demand determinations are made from a remote target site. Method according to one or more of Claims 1 to 4, characterized in that any of the definitions i), ii) and iii) of the selected determination is carried out programmatically, if any of the definitions i), ii) and iii) is selected the determination produces a result that exceeds a predetermined maximum value or does not reach a predetermined minimum value or deviates from a predetermined result of that first determination for a predetermined minimum value. A method according to one or more of claims 1 to 8, characterized in that it is program controlled i) carry out the determination of the surfactant content, where: a) take a sample of a predetermined volume from the aqueous process solution, b) release the particulate sample if desired, c) if desired, dilute the sample with water in a predetermined ratio or in a ratio resulting from a preliminary determination. d) determine the content of the surfactants by selective adsorption, electrochemical, chromatographic, by grafting on the volatile compounds, distillation of these volatile compounds and their detection, or by adding a reagent which changes the sample's action by electromagnetic radiation in proportion to the content of the surfactants, and performs the measurement of the changing effect . Process according to one or more of Claims 1 to 8, characterized in that (ii) the inorganic and / or organically bound carbon loading is determined while being programmatically controlled a) to take a sample with a predetermined volume from the treatment bath, b) optionally release and / or homogenize the particulate sample, c) if desired, dilute the sample with water in a predetermined or as a result of a preliminary determination of the ratio obtained, d) determine the content of inorganic and / or organically bound carbon in the sample by a known process. Process according to one or more of Claims 1 to 8, characterized in that (iii) the alkalinity of the cleaning bath is determined by an acid-base reaction with an acid, which is program controlled a) take a sample of the intended volume from the treatment bath, b) release the particulate sample if desired, c) select whether free alkalinity and / or total alkalinity should be determined, and d) the sample titrates or presents the acid with the addition of acid and titrates the sample. Method according to one or more claims Idols, characterized in that for each of the determinations i), ii) and iii), a determination is made at a predetermined time interval or after a predetermined number of determinations or on the basis of a command from a remote target location s the control measurement of one or more standard solutions checks the functional capability of the measuring apparatus used and transmits the result of the test to a distant target. Method according to one or more of Claims 1 to 11, characterized in that for each of the determinations i), ii) and iii) the determination determined by means of a control measurement of one or more standard solutions checks the functional capability of the measuring device used, the two consecutive determinations are different for the preset value and that the results of the check are transmitted to the remote destination. Method according to claims 12 or 13, characterized in that, depending on the verification of the measuring device used, they are equipped during the current and preliminary control measurement of the determined determination with a status sign indicating the reliability of these determinations. Method according to one or more of Claims 1 to 14, characterized in that, depending on the result of one or more determinations (i), (ii) and (iii), an additional dosage of supplementary components and / or or one or more bath care measures. Method according to one or more of Claims 1 to 14, characterized in that, depending on the result of one or more of the determinations i), ii) and iii), the selected dosage or selected determinations are programmatically controlled to introduce additional dosing of the supplementary components and / or one or more bath care measures. Process according to one or more of Claims 1 to 14, characterized in that additional dosage of the supplemental components and / or one or more bath care measures is introduced by the program-controlled operation, if the predefined relationships between the results of at least two of the determinations are fixed i) , ii) or iii) selected determinations.