DE102013112302A1 - Device for producing galvanic coatings - Google Patents

Abstract

A method and an apparatus (01) for producing galvanic coatings are described. The method provides that an electrolyte associated with a sacrificial material circulates in a circuit (10) in the circuit (10) a dissolved in the electrolyte starting material or sacrificial material as a galvanic coating on a workpiece, which as Cathode is contacted electrically disposed in the electrolyte, is deposited, seen in the circulation direction (06) in the circuit (10), before the dissolved in the electrolyte starting material or sacrificial material is deposited as a galvanic coating on a workpiece during the galvanization gas produced in the circuit is separated from the electrolytes along with this carried along with electrolytes, then the entrained gas entrained electrolytes are filtered, and the remaining, separated from the electrolyte gas from the circuit (10) is removed. The device (01) comprises at least one process space (02), in which at least one workpiece to be provided with a galvanic coating and an electrolyte are introduced. The electrolyte is in contact with a starting material or sacrificial material which is soluble therein and provides the material for the coating. A reactor space (03), in which the starting material or sacrificial material is introduced into the electrolyte, is connected to the process space (02) via a feed line (04) and via a discharge line (05). Process space (02) and reactor space (03) are parts of a circuit (10) in which the electrolyte circulates and to which a gas separation space (07) communicates or in which a gas separation space (07) is arranged. During the production of galvanic coatings in the electrolyte resulting gas escapes in or in the gas separation space (07) and can be removed from the circuit (10).

Description

The invention relates to a device for producing galvanic coatings according to the preamble of claim 1.

In the production of galvanic coatings, chemical processes occur under the action of electrical current. By applying a DC voltage to two via an electrically conductive liquid (electrolyte) in contact with each other, an electric current flows between them. The electric current is formed by the movement of the positive cations to the negatively charged electrode (cathode) and the negative anions to the positively charged electrode (anode). Oxidative processes take place at the anode while the surface of the cathode is reduced.

Here, a distinction is made between soluble and insoluble anodes. The soluble anode itself provides a source or sacrificial material which provides the material for the coating. In the insoluble anode, the starting or sacrificial material is in the electrolyte or in the bath.

In order to constantly provide sufficiently dissolved starting material or sacrificial material in the electrolyte or bath in the case of an insoluble anode or to dissolve it in the electrolyte or in the bath, plates, sheets, profiles are filled in a dissolving tank filled with the same electrolyte etc. chemically dissolve from starting or sacrificial material. The electrolyte in the dissolving tank communicates with the bath in which the starting or sacrificial material dissolved in the electrolyte is deposited as a galvanic coating on a workpiece which is arranged in the electrolyte as a cathode in electrical contact.

The production of galvanic coatings is mainly associated with a handling of one or more harmful to health and / or the environment. These are predominantly z. As serving as electrolytes liquids and partly also to solids. The liquids may, for example, be pure substances or mixtures of substances or compounds of several substances in liquid form, solutions of one or more gaseous, solid or liquid substances in one or more liquid solvents or solvents, as well as emulsions. Examples are z. As acids or alkalis. The solid substances may be, for example, starting or sacrificial materials. The starting or sacrificial materials may be gradually soluble in a liquid serving as an electrolyte.

Galvanization produces gas bubbles which disturb the plating process and thus the formation of uniform coatings due to their presence, as well as some toxic substances in the form of aerosols from the electrolyte or bath.

In order to reduce the endangerment of the environment by the escaping gas bubbles and electrolytes entrained therefrom, it is known to allow the plating process to take place in a closed process space, which is connected to the dissolution bath via feed and discharge lines. In this case, the electrolyte circulates in a circuit which separates the dissolving tank, the process space in which the starting material or sacrificial material dissolved in the electrolyte is deposited as a galvanic coating on a workpiece which is electrically contacted as a cathode in the electrolyte, and the dissolving tank and The supply and discharge lines interconnecting the process space comprises. The gas bubbles and electrolytes carried by these can only escape from the dissolving bath. The substances escaping from the dissolving bath are passed through filter systems, so that a risk to the environment is minimized.

A disadvantage of this arrangement is that the filter systems require a very high power in order to cope with the amount of gas escaping from the dissolving bath and the electrolyte transported by it. This results in high running costs through the operation of the filter systems and high initial costs due to the need for high throughput filter systems.

In order to avoid that in case of a leak or inappropriate handling one or more of the substances required for the production of galvanic coatings escape uncontrolled or thereby incompatible substances come into contact with each other, is by EP 0 445 120 B1 it is known to set at least one process space in which the actual production process of galvanic coatings takes place under negative pressure relative to the environment. In the case of a leak so penetrates from the environment z. For example, air or another gas or gas mixture located there in the process space, instead of a substance from the process space injected into the environment. This reduces the risk of health or environmental damage from a leak.

By JP 06180000 A It is known to replace ions consumed in electroplating using insoluble anodes by dissolving a metal granulate. In this case, spent electrolyte is supplied by means of a pump from a treatment bath of a dissolving device, which contains a Fe-Zn granules, which is there to accumulate the electrolyte in Fe ²⁺ - and Zn ²⁺ ions dissolved. The pH of the spent electrolyte is measured at the inlet of the dissolver and the pH of the enriched electrolyte at the outlet of the dissolver. In order to avoid the formation of residues, also referred to as sludge, the effluent quantity from the bath is adjusted so that the difference of the pH values is ≤ 0.5. A disadvantage of this is an environmentally harmful and also dangerous to handle treatment in open bath and also a variable with changing the pH at the entrance of the dissolver zone concentration in the bathroom along with a nonuniform layer structure in the treatment.

It is an object of the invention to provide a method and an apparatus for producing galvanic coatings, of which particularly advantageously a low risk of health or environmental damage emanating from a leak, and which can be realized and operated inexpensively.

The stated object is achieved in each case by the features of the independent claims.

A first subject of the invention accordingly relates to a process for producing galvanic coatings.

The method provides that an electrolyte associated with a sacrificial material circulates in a preferably closed circuit. In the cycle, a starting material or sacrificial material dissolved, for example, batchwise or continuously in the electrolyte, is deposited as a galvanic coating on a workpiece, which is arranged in the electrolyte as a cathode in electrical contact.

The method is characterized in that, seen in the circulation direction in the cycle, before the dissolved in the electrolyte starting material or sacrificial material is deposited as a galvanic coating on a workpiece during the galvanization in the preferably closed circuit resulting gas in addition to this mitbeförderte aerosols of the electrolyte or its liquid phase is deposited. The deposition of the gas from the electrolyte is preferably carried out under negative pressure relative to an environment outside the circuit. Subsequently, the entrained gas entrained electrolytes are filtered. The filtered aerosols can be returned to the electrolyte. The remaining, separated from the electrolyte gas is removed from the preferably closed circuit.

The method may provide that at least the deposition of the sacrificial material or starting material as a galvanic coating on a workpiece, which is arranged in the electrolyte in the form of a cathode, takes place under a negative pressure, at least in relation to an environment outside the circuit.

Gas separation can occur at a highest point in the cycle.

The gas separation preferably takes place in a closed gas separation space arranged in the circuit, which communicates with the circuit and / or has an electrolyte level. The surface of such an electrolyte mirror is preferably smaller than the surface of an electrolyte mirror in a process space of the circuit, in which the starting or sacrificial material dissolved in the electrolyte is deposited as a galvanic coating on a workpiece. Alternatively or additionally, the surface of such an electrolyte mirror is preferably smaller than the surface of an electrolyte mirror in a reactor space of the circuit in which the sacrificial material is introduced into the circulating electrolyte and dissolved.

Advantages of the method over the prior art include a significantly reduced amount of exhaust air to be treated compared to filtering a gas escaping a dissolving bath. This allows cost savings in terms of dimensioning of the filter system and their operating costs.

A second object of the invention making use of the advantages of the method relates to a device for producing galvanic coatings. The device comprises at least one preferably closed, particularly preferably closed process space. The process space can accommodate at least one workpiece to be provided with a galvanic coating. For example, one or more workpieces can be introduced in batches into the process space.

Alternatively, it is conceivable that the workpieces go through the process space. For this purpose, a transport device running through the process space can be provided, for example a conveyor belt equipped with gripping arms or with receptacles for the workpieces or a transport chain.

In the at least one process space, an electrolyte can be introduced or introduced, the with a soluble therein, the material for the also referred to as a coating layer structure available the parent or sacrificial material.

The closed or closed process space avoids the disadvantages of open bathrooms, such as environmental damage caused by escaping gases and electrolytes as well as hazardous handling during treatment.

The starting material or sacrificial material is connected to an electrolyte at least during the layer construction of the galvanic coating. The sacrificial material is soluble in the electrolyte. At least a portion of the electrolyte associated with the sacrificial material is in the process space, at least during fabrication or buildup of the plating.

The process space communicates via a feed line and a discharge fluidly with one or more closed, preferably closed reactor chambers in connection, so that an introduced into the process space electrolyte communicates via the supply and discharge lines with the at least one reactor space. In the at least one reactor space, the starting or sacrificial material making available the material for the coating is introduced into the electrolyte.

The process space, the discharge, the reactor space and the supply line form a closed, preferably closed circuit, in which the electrolyte circulates.

The starting material or sacrificial material dissolved in the electrolyte in the reactor chamber is deposited as a galvanic coating on a workpiece introduced into the process chamber, which is arranged in the electrolyte as a cathode in electrical contact.

The device is characterized by arranged in the closed circuit means for gas separation.

The gas separation means arranged in the closed circuit may be, for example, at least one gas separator.

The circuit comprises at least: supply line, process space, discharge, reactor space, means for gas separation or gas separator. The order of enumeration of the elements of the cycle does not have to correspond to their arrangement sequence within the cycle. Also, the order of enumeration does not specify a circulation direction of the electrolyte in the circulation.

Viewed in the circulation direction of the electrolyte in the circuit, the means for gas separation or the gas separator is preferably arranged after the reactor space and in front of the process space.

The means for gas separation or the at least one gas separator comprise at least one gas separation space, which is arranged either in the supply line to the process space, or in the discharge from the reactor space and / or communicates with one of the two lines. Particularly preferably, the gas separation space is arranged in the supply line to the process space or communicates with the supply line to the process space.

Preferably, the means for gas separation or the gas separator is arranged in the circulation direction of the electrolyte within the circuit before the process space and after the reactor space in the circuit. In other words, the gas separator is preferably arranged in the supply line to the process space. Alternatively or additionally, the gas separator may be provided in the discharge from the process space.

Within the gas separation space, there may be an electrolyte level above which electrolyte level a trap may be provided for one or more gas phases. In addition, the gas separation space may comprise an inlet mouth, a drain mouth, both of which are arranged below an electrolyte level optionally formed in the gas separation space, and a gas phase discharge mouth above an electrolyte level optionally formed in the gas separation space.

Alternatively, the gas separation space may communicate with the circuit, for example, by communicating with the supply line to the process room.

The gas separation is preferably carried out in a closed gas separation space arranged in the circuit, which has an electrolyte level which is smaller than the surface of an electrolyte mirror in a process space of the circuit in which the starting material or sacrificial material dissolved in the electrolyte is in the form of a galvanic coating is deposited on a workpiece and which is smaller than the surface of an electrolyte level in a reactor space of the circuit in which the sacrificial material is introduced and dissolved in the circulating electrolyte.

In the gas separation space, for example, between an optionally formed in the gas separation space electrolyte level and a gas phase discharge orifice, a filter device can be provided which retains electrolytes transported by the gas phase to be separated out and, if appropriate, feeds it back to the electrolyte.

The filter device may comprise, for example, a gas scrubber, for example a water alkali scrubber, which returns the proportion of electrolyte in the excreted gas to a permissible value before the then purified gas is released into the environment.

At the gas phase discharge port, a vacuum pump may be connected. This can suck the gas phase from the gas separation space, preferably never completely, but always in such a way that it is ensured that the vacuum pump does not suck in any electrolyte or liquid medium. The term vacuum pump is hereby representative of any means which are suitable for sucking out a gaseous medium from a room and in the space opposite an environment in which the space is arranged and / or in which environment the means for removing the gaseous medium removed from the space to produce a negative pressure.

The generation of a negative pressure in the gas separation has the advantage here that the saturation of a gas in a liquid also decreases with decreasing pressure, whereby the separation of the gas is accelerated and simplified. As a result, a substantially smaller surface area of an electrolyte mirror is sufficient in comparison to a degassing taking place under ambient pressure or even overpressure.

As the surface of the electrolyte level decreases, the amount of electrolytes emanating from the surface of the electrolyte level in the deposited gas also decreases. As a result, in addition to the prior art, a smaller amount of exhaust air must be treated than above an electrolyte level, for example, a dissolving tank, in which in the prior art, the starting or sacrificial material is introduced and dissolved in the electrolyte, or a bath, in which at State of the art, the dissolved in the electrolyte starting or sacrificial material is deposited as a galvanic coating on a workpiece.

If the gas separation chamber only communicates with the circuit, then the surface of the electrolyte mirror is formed as small as possible.

The vacuum pump comprises, is encompassed or advantageously forms means with which, in addition to the gas separation space, also in other parts of the cycle, preferably at least in the process space, a negative pressure relative to an ambient pressure prevailing in an environment outside the process space can be generated.

A valve may be provided between the gas phase discharge port and the vacuum pump connected thereto, which prevents backflow of gaseous and / or liquid media into the gas separation space due to a negative pressure prevailing there in relation to other regions, in particular in relation to an environment.

Advantages which additionally result from the gas separator are that it ensures that the electrolyte flows free of gas bubbles, which disturbs the production of uniform electroplated coatings, for example with regard to the construction of uniform layer thicknesses, at least the process space. An additional advantage results from the fact that the gas separation can be used simultaneously to generate the negative pressure not only in the process room, but preferably in the entire cycle. In this case, a negative pressure can be generated by the separated gas phase is withdrawn from the gas separator.

Benefits also provided by the gas separator are that it can provide filtering equipment which, in comparison with the prior art, requires significantly less power to cope with the amount of escaping gas and electrolytes. As a result, compared to the prior art, the costs incurred by the operation of the filter systems running costs and the costs incurred by the need for low-performance filter systems cost significantly reduced. In addition, the gas separator has a small surface area of the electrolyte level compared to the prior art.

As the surface decreases, the electrolyte simultaneously loses less and less toxic substances in the form of electrolytes. As a result, a reduction of the amount of exhaust air to be filtered is achieved with decreasing surface of the electrolyte mirror. Nevertheless, in order to enable a reliable degassing, at least the gas separation space is under a negative pressure compared to a pressure which would prevail in the electrolyte in an open dissolving tank.

Preferably, at least the process space, for example at least during the operation of the gas separator and / or at least during the production of a coating, is completely flooded by the electrolyte.

Alternatively or additionally, at least the reactor space, for example, at least during operation of the gas separator and / or at least during the production of a coating to be completely flooded with electrolyte.

In any case, there is an electrolyte level in the gas separation space, which ensures that an outlet opening and, if appropriate, an inlet opening lie below the electrolyte level. This ensures that no gas phase from the gas separation chamber of the gas separator enters the circuit.

The supply line to the process space and the discharge from the process space preferably open at locations remote from one another into the process space. Likewise, it is preferable for the mouths of the supply line to the reactor space and / or the discharge from the reactor space. Suitable remote locations include, for example, a mouth of the supply line to the process space near the electrolyte level in the process space and an outlet of the discharge from the process space at the bottom of the process space. In addition, the two orifices may be disposed on opposite sides of the process space. Particularly preferred are a plurality of orifices of the supply line to the process space z. B. above or below the electrolyte surface forming the electrolyte surface in the process space provided. In this case, a mouth of the derivative of the process space z. B. be provided centrally in the bottom of the process room. Alternatively, several mouths of the derivative of the process space z. B. may be provided evenly distributed over the bottom of the process space. The same applies to the reactor space, with the difference that the outlet of the discharge from the reactor space is preferably provided at the bottom of the reactor space and the mouth of the feed line to the reactor space above, at or preferably below the electric mirror in the reactor space.

At least in the discharge from the process space into the reactor space, a conveying device is preferably arranged. The conveyor removes, for example, continuously electrolyte via the discharge from the process chamber and it leads to the reactor space. At the same time, the same amount of electrolyte flows from the reactor space into the process space via the supply line. In this way, a circuit is formed which, viewed in the flow direction from the reactor chamber, is composed of reactor space, discharge from the reactor space, gas separation space, supply line to the process space, process space and discharge from the process space back into the reactor space. In the reactor space, this results in a continuous mixing of the electrolyte removed from the process space with the starting material or sacrificial material introduced into the reactor space, for example in the form of a granulate. As a result, a uniformly high concentration of starting material or sacrificial material dissolved in the electrolyte is achieved in the smallest space in the reactor space, before the electrolyte thus enriched with starting or sacrificial material passes out of the reactor space and through the gas separation space via the supply line back to the process space is supplied.

At least during the production of the galvanic coating, a starting material or sacrificial material in the form of a granulate which provides the material for the coating can preferably be introduced continuously into the reactor space. The granules of the starting or sacrificial material are soluble in the electrolyte. By means of a preferably arranged in the discharge from the process chamber in the reactor chamber space conveyor, the electrolyte is circulated continuously with its in the reactor chamber high concentration of dissolved therein starting material or sacrificial material in the circuit, for example. The circulation is particularly preferably carried out in such a way that the electrolyte in the process space, at least during the production of a galvanic coating, has a uniform concentration of granules or ions dissolved therein.

The flowing from the reactor space via the feed line into the process chamber electrolyte contains by the preferably continuous, continuous introduction of granules into the reactor space and by the constant mixing with the withdrawn from the process chamber electrolyte a consistently high concentration of the material for the production of electroplated coatings Providing ions or dissolved starting or sacrificial material. Due to the constant mixing of the electrolyte in the process chamber by supplying electrolyte with a high concentration of dissolved starting material or sacrificial material from the reactor space into the process space with simultaneous removal and return of electrolyte from the process space into the reactor space, a uniform and high concentration is likewise produced dissolved starting material or sacrificial material in the process space. This ensures a uniform layer structure and a uniform layer thickness of the galvanic coating.

The mixing of the electrolyte removed from the process space with the granules in the reactor space moreover ensures an effective and rapid solution of the starting or sacrificial material in the smallest space. As a result, the reactor space can be made substantially smaller in volume than a dissolution tank known from the prior art.

It is important to emphasize that in principle it is also possible to arrange the conveying device elsewhere in the described cycle or to additionally arrange at least one further conveying device at at least one other point in the described cycle.

Such a conveying device arranged at least in the discharge from the process space can serve or contribute to maintaining a negative pressure in the process space with respect to an ambient pressure prevailing in the environment of the process space.

Between the reactor space and the gas separation space, a throttle z. B. may be introduced in the form of a valve, so that a in the discharge from the process chamber arranged in the reactor space conveyor can only promote the generation of a negative pressure in the gas separation space and in the process space from the environment electrolyte from the process chamber into the reactor space. This has the advantage that even with prevailing in the reactor chamber ambient pressure of the negative pressure in the process chamber can be maintained. As a result, the feed of the reactor space with starting or sacrificial material is substantially simplified.

The device may further comprise means for preferably continuous introduction of sacrificial material in the form of post-charging of the dissolved parent or sacrificial material consumed at the prevailing amount of current through the layered structure of the electrodeposited coating. The recharging preferably takes place in the reactor space. Since the reactor space itself does not have to be under negative pressure, the continuous introduction of starting material or sacrificial material into the reactor space can be realized simply and inexpensively, for example by means of a metering device. In this case, the metering device can be controlled on the basis of the actual consumption of starting or sacrificial material during the layer construction. The use of starting or sacrificial material in the form of granules also has the advantage of the possibility of a very exact dosage.

In the line between the reactor space and the gas separation space, a filter can be arranged which retains undissolved particles, for example, of the starting or sacrificial material. The filter prevents particles from starting material or sacrificial material not yet dissolved in the electrolyte from being able to enter the gas separation space and from there into the process space. As a result, a reduction in the quality of the produced or produced galvanic coating z. B. prevented by itself on the surface of your workpiece small particles knocking down particles.

The device preferably comprises means for maintaining a uniform concentration of the soluble starting material or sacrificial material providing the material for the coating or ions originating therefrom and providing the material for producing galvanic coatings in the electrolyte during the layer construction of the galvanic coating , In this case, the ions are particularly preferably made available, as described above, by a granulate of the starting or sacrificial material, which is soluble in the electrolyte to form ions.

The means for maintaining a uniform concentration of ions in the electrolyte may include means for measuring the ion concentration of the electrolyte in the process space, a controller connected to the apparatus, and means for controlling and accumulating ions in the electrolyte in the process space connected to and controllable by the controller.

The means for accumulating ions in the electrolyte in the process space may comprise a previously described, separate from the process chamber reactor space, further preferably lockable supply and discharge lines and one or more example arranged herein, as controllable pumps and / or controllable valves running, by means of Control device in their capacity controllable conveyors through which the reactor space is connected to the process room.

When the zone concentration of the electrolyte in the process space changes, this is detected via the device for measuring the ion concentration of the electrolyte in the process space, which sends a corresponding signal to the control device. The control device then changes the amount of the electrolyte flowing out of the process space via the discharge into the reactor space and thus also the amount of electrolyte flowing from the reactor space via the supply line into the process space such that the ion concentration in the electrolyte remains the same in the process space. For this purpose, the control device can comprise integral and / or linear and / or differential control elements, as known from control technology, in order to ensure the most uniform possible concentration.

The control device can moreover have output means, for example in the form of an acoustic and / or visual display, such as a warning light, with which, for example, a decreasing concentration of dissolved starting material or sacrificial material in the reactor space can be pointed, for example, to cause refilling of, for example, granules of a starting or sacrificial material.

Alternatively or additionally, the control device may regulate any means provided for preferably continuous introduction of starting material or sacrificial material in the form of a recharging of the dissolved starting material or sacrificial material consumed by the layer structure of the galvanic coating at prevailing current intensity in such a way that consumed starting material or sacrificial material is replaced at the same time or at least in a timely manner.

An essential difference of the method according to the invention and the device according to the invention over the prior art is that gas bubbles produced during the galvanization are not simply released from the electrolyte, whereby large amounts of exhaust air have to be treated, but the electrolyte is passed through a gas separation space, in which negative pressure In contrast to an environment prevails, so that the excretion of the gas bubbles is accelerated compared to a precipitation under ambient pressure. Due to the negative pressure, a substantially lower surface area of the electrolyte level is required for the same effectiveness of the gas excretion than would be required to maintain the same effectiveness of the gas excretion under ambient pressure. An immediate advantage of this is that the amount of electrolytes discharged from the electrolyte, which amount is decisive for the size of the exhaust air stream to be cleaned by filter systems, also decreases with decreasing surface area of the electrolyte mirror. As a result, by means of a gas separation under reduced pressure with respect to an environment, a lesser exhaust air flow to be filtered is obtained, than with a gas separation under the pressure prevailing in the environment.

At the same time, the negative pressure in the gas separation space can be used to maintain a negative pressure relative to the environment in the entire electrolyte circuit. For example, by suction of the gas phase from the gas separation space in the entire electrolyte circuit, a negative pressure to an environment can be generated and maintained.

The invention will be explained in more detail with reference to embodiments shown in the drawings. Therein, like reference characters designate like or equivalent elements. The only 1 shows in a schematic representation:

1 a device for producing galvanic coatings.

An in 1 completely or partially illustrated device 01 for the production of galvanic coatings comprises at least one process space 02 , In the process room 02 At least one to be provided with a galvanic coating workpiece and an electrolyte can be introduced or introduced. The electrolyte is in contact with a starting material or sacrificial material which is soluble therein and provides the material for the coating. The device 01 also includes a reactor room 03 in which the starting or sacrificial material is introduced into the electrolyte. The reactor room 03 is via a supply line 04 and about a derivative 05 with the process room 02 connected. The reactor room 03 , the supply line 04 , the process space 02 and the derivative 05 are part of a closed cycle 10 within which the electrolyte as indicated by arrows 06 indicated circulated.

The device 01 is characterized by one in the cycle 10 arranged gas separation space 07 out.

Through the gas separation room 07 The resulting advantages are that this filter systems can be provided, which require compared to the prior art much lower power to cope with the amount of escaping gas and the electrolyte. As a result, compared to the prior art, the costs incurred by the operation of the filter systems running costs and the costs incurred by the need for low-performance filter systems cost significantly reduced. The gas separation space 07 moreover, there is no or, compared to the prior art, only a small surface area of an electrolyte mirror optionally formed in it 08 on. As the size of such a surface decreases, the electrolyte simultaneously releases less and less toxic substances in the form of electrolytes. This is done with decreasing surface of an electrolyte mirror 08 in the gas separation room 07 achieved a reduction in the amount of exhaust air to be filtered. In order nevertheless to enable reliable degassing, at least the gas separation space is available 07 preferably under a negative pressure to a pressure in an environment outside the circuit 10 For example, under a negative pressure to a pressure which would prevail in the electrolyte in an open dissolving tank.

The gas separation space 07 at least communicates with the cycle 10 , preferably with the supply line 04 , In this case, preferably, there is no surface of an electrolyte mirror in the gas separation space 07 educated. During the production of galvanic surfaces in the electrolyte resulting gas can from the circulating 10 circulating electrolyte in the circulation communicating gas separation space ( 07 ) escape and thereby the cycle ( 10 ). Alternatively or additionally, the gas separation space 07 in the cycle 10 be arranged. In this case, the electrolyte in the gas separation space 07 a surface with an electrolyte mirror 08 form above which electrolyte level 08 There is a trap for one or more gas phases, so that during galvanization in the cycle 10 resulting gas in the gas separation space 07 escape from the electrolyte into the trap and thereby the circulation 10 can be removed.

The surface of such an electrolyte mirror 08 is preferably smaller than the surface of an optionally in the process space 02 of the cycle 10 formed electrolyte mirror, in which the dissolved in the electrolyte starting or sacrificial material is deposited as a galvanic coating on a workpiece. Alternatively or additionally, the surface of such an electrolyte mirror 08 preferably smaller than the surface of an optionally in the reactor space 03 of the cycle 10 trained electrolyte mirror 30 in which the starting or sacrificial material in the in circulation 10 circulating electrolyte is introduced and dissolved.

At least during the production of galvanic coatings, at least in the gas deposition space 07 a negative pressure to a pressure in an environment outside the circuit 10 to rule.

The generation of a negative pressure in the gas separation has the advantage here that the saturation of a gas in a liquid also decreases with decreasing pressure, whereby the separation of the gas is accelerated and simplified. As a result, a much smaller surface of an electrolyte mirror is sufficient 08 in comparison to a degassing taking place under ambient pressure or even overpressure.

With decreasing surface of the electrolyte mirror 08 Also decreases the amount of the surface of the electrolyte mirror 08 outgoing electrolytes in the separated gas. As a result, in addition to the prior art, a smaller amount of exhaust air must be treated than above an electrolyte level, for example, a dissolving tank, in which in the prior art, the starting or sacrificial material is introduced and dissolved in the electrolyte, or a bath, in which at State of the art, the dissolved in the electrolyte starting or sacrificial material is deposited as a galvanic coating on a workpiece.

The negative pressure in the gas separation space 07 can at least in part by removal of in the gas separation space 07 collected, excreted from the electrolyte gas from the gas separation space 07 be prepared.

At the in 1 illustrated device 01 is formed in the electrolyte by electrochemical and / or electro-galvanic processes resulting gas in a relation to an environment preferably closed, more preferably completed gas separation space 07 from the electrolyte in the circulation 10 separated. By a suction this in the gas separation space 07 for example above an electrolyte level 08 collecting gas from the circulation 10 can at least in the gas separation space 07 , preferably throughout the cycle 10 a negative pressure to an environment outside the circuit 10 generated and maintained.

Electrolytes entrained by the separated gas may still be present in the gas separation space 07 be filtered, for example by means of a gas scrubber.

A gas scrubber is a process engineering apparatus in which a gas stream is contacted with a liquid stream to receive components of the gas stream in the liquid. The passing components of the gas stream may be solid, liquid or gaseous substances. As washing liquid pure solvents, such as water, but also suspensions such as milk of lime can be used.

The filtered electrolytes can be returned to the electrolyte.

Preferably, in the circulation direction of the electrolyte in the circulation 10 seen the gas separation space 07 after the reactor room 03 and in front of the process room 02 arranged.

The gas separation space 07 can be an inlet outlet 70 , a drain outlet 71 which are both below an optionally in the gas separation space 07 trained electrolyte mirror 08 may be arranged, and above the optionally in the gas separation space 07 trained electrolyte mirror 08 a gas phase discharge mouth 72 include.

Before the gas phase discharge mouth 72 For example, a filter device may be provided in the form of a previously described gas scrubber, which retains electrolytes transported by the excreted gas and optionally re-supplies it to the electrolyte.

At the gas phase discharge mouth 72 a vacuum pump can be connected. This may be the separated gas from the gas separation space 07 suck, preferably never completely, but always so that it is ensured that the vacuum pump sucks no electrolyte or no liquid medium. The term vacuum pump is hereby representative of any means which are suitable to suck a gaseous medium from a room and preferably in the room opposite an environment in which the space is arranged and / or in which environment the means removed from the space gaseous Move medium to generate a negative pressure.

The vacuum pump comprises, is encompassed, or advantageously forms means with which, except in the gas separation space 07 also in other parts of the cycle 10 , preferably at least in the process space 02 , a negative pressure relative to one in an environment outside the process space 02 generate prevailing ambient pressure.

Through the gas separation room 07 additional advantages are that it ensures that the electrolyte free of gas bubbles, which interferes with the production of uniform electroplated coatings, for example, with regard to the structure of uniform layer thicknesses, at least the process space 02 flooded. An additional advantage results from the fact that the gas deposition at the same time to generate the negative pressure not only in the process room 02 but preferred throughout the cycle 10 can be used. In this case, a negative pressure can be generated by the separated gas from the gas separation space 07 is deducted.

In the cycle 10 For example, between the reactor room 03 and the gas separation space 07 a conveyor 09 be arranged for example in the form of a pump.

The conveyor 09 For example, continuously withdraws electrolyte from the reactor space 03 and leads it to the gas separation space 07 to. Simultaneously flows over the derivative 05 the same amount of electrolyte from the process room 02 in the reactor room 03 to.

Preferably at the highest point in the cycle 10 arranged gas separation space 07 there is negative pressure at least to an environment outside the circuit 10 and preferably also over other parts of the cycle 10 , In the gas separation room 07 can be an open electrolyte level 08 be formed so that in the electrolyte during the production of galvanic coatings forming and possibly in the electrolyte partially dissolving gas can be deposited in the gas separation space.

The conveyor 09 thus generates a circulation of the electrolyte in the circulation 10 , The circulation occurs in the reactor space 03 to a constant mixing of the electrolyte with the in the reactor space 03 for example, in the form of granules introduced starting or sacrificial material. As a result, in the smallest space in the reactor space 03 reached a uniformly high concentration of dissolved in the electrolyte starting or sacrificial material before the thus enriched with starting or sacrificial material electrolyte from the reactor space 03 out and through the gas separation room 07 through via the supply line 04 the process room 02 is supplied.

In the process room 02 the circulation also achieves a uniform concentration of starting or sacrificial material dissolved in the electrolyte, which benefits a particularly uniform layer structure in the production of galvanic coatings.

At least during the manufacture of galvanic coatings, at least in the process space 02 a negative pressure relative to one in an environment outside the circuit 10 be maintained or generated prevailing ambient pressure. The negative pressure in the process room 02 may be at least in part by removing the gas separated from the electrolyte from the gas separation space 07 be prepared.

An essential difference of the described devices according to the invention 01 Compared with the prior art, the gas bubbles produced during the galvanization are not simply released from the electrolyte in a flash bath, which requires the treatment of large amounts of exhaust air, but rather the electrolyte through a gas separation space 07 in which there is preferably negative pressure relative to an environment, so that the excretion of the gas bubbles is accelerated in comparison to an excretion under ambient pressure. Due to the negative pressure, a substantially lower surface area of the electrolyte level is required for the same effectiveness of the gas excretion than would be required to maintain the same effectiveness of the gas excretion under ambient pressure. An immediate advantage of this is that the amount of electrolytes discharged from the electrolyte, which amount is decisive for the size of the exhaust air stream to be cleaned by filter systems, also decreases with decreasing surface area of the electrolyte level. As a result, by means of a gas separation under reduced pressure with respect to an environment a lesser to be filtered Exhaust air flow obtained, as in a gas separation under the pressure prevailing in the environment.

• – ein mit einem Ausgangs- bzw. Opfermaterial in Verbindung stehender Elektrolyt in einem vorzugsweise geschlossenen Kreislauf 10 zirkuliert,
• – in dem Kreislauf 10 ein beispielsweise chargenweise oder kontinuierlich im Elektrolyt gelöstes Ausgangs- bzw. Opfermaterial als galvanischer Überzug auf einem Werkstück, welches als Kathode elektrisch kontaktiert im Elektrolyt angeordnet ist, abgeschieden wird,
• – in durch Pfeile 06 angedeuteter Zirkulationsrichtung in dem Kreislauf 10 gesehen, bevor das im Elektrolyt gelöste Ausgangs- bzw. Opfermaterial als galvanischer Überzug auf einem Werkstück abgeschieden wird, während der Galvanisierung im vorzugsweise geschlossenen Kreislauf 10 entstehendes Gas nebst von diesem mitbeförderte Elektrolyte von dem Elektrolyt bzw. dessen flüssiger Phase vorzugsweise unter Unterdruck gegenüber einer Umgebung abgeschieden wird,
• – anschließend die vom abgeschiedenen Gas mitgeführten Elektrolyte gefiltert werden, und
• – das verbleibende, von den Elektrolyten getrennte Gas aus dem vorzugsweise geschlossenen Kreislauf 10 entfernt wird.

The devices described 01 are suitable for carrying out a gas separation process in which:

• An electrolyte associated with a source or sacrificial material in a preferably closed circuit 10 circulated
• - in the cycle 10 a starting material or sacrificial material dissolved, for example, batchwise or continuously in the electrolyte, is deposited as a galvanic coating on a workpiece which is arranged in the electrolyte as a cathode in an electrically contacted manner,
• - in by arrows 06 indicated circulation direction in the circuit 10 seen before the dissolved in the electrolyte starting material or sacrificial material is deposited as a galvanic coating on a workpiece during the galvanization in the preferably closed circuit 10 emerging gas together with this mitbeförderte electrolytes of the electrolyte or its liquid phase is preferably deposited under negative pressure to an environment
• - Then the entrained gas entrained electrolytes are filtered, and
• - The remaining, separated from the electrolyte gas from the preferably closed circuit 10 Will get removed.

• – die gefilterten Elektrolyte dem Elektrolyt wieder zugeführt werden, und/oder
• – das während der Galvanisierung entstehende Gas nebst von diesem mitbeförderte Elektrolyte von dem Elektrolyt bzw. dessen flüssiger Phase unter einem Unterdruck gegenüber einer Umgebung außerhalb des Kreislaufs 10 abgeschieden wird, und/oder
• – zumindest die Abscheidung des Ausgangs- bzw. Opfermaterials als galvanischer Überzug auf einem Werkstück, das als Kathode elektrisch kontaktiert im Elektrolyt angeordnet ist, unter einem Unterdruck zumindest gegenüber einer Umgebung außerhalb des Kreislaufs 10 erfolgt, und/oder
• – die Gasabscheidung an einem höchsten Punkt des Kreislaufs 10 geschieht.

The method may provide that:

• - The filtered electrolytes are returned to the electrolyte, and / or
• - The resulting during the galvanization gas together with this mitbeförderte electrolytes of the electrolyte or its liquid phase under a negative pressure relative to an environment outside the circuit 10 is deposited, and / or
• - At least the deposition of the starting or sacrificial material as a galvanic coating on a workpiece, which is arranged as a cathode electrically contacted in the electrolyte, under a negative pressure at least against an environment outside the circuit 10 takes place, and / or
• - the gas separation at a highest point of the cycle 10 happens.

According to the method, the gas separation is preferably carried out in one in the cycle 10 arranged closed gas separation space 07 who has an electrolyte level 08 having a surface area smaller than the surface of an electrolyte mirror in a process space of the circuit 10 in which the starting or sacrificial material dissolved in the electrolyte is deposited as a galvanic coating on a workpiece, and / or which is smaller than the surface of an electrolyte mirror 30 in a reactor room 03 of the cycle 10 in which the starting or sacrificial material in the in circulation 10 circulating electrolyte is introduced and dissolved.

Advantages of the method over the prior art include a significantly reduced amount of exhaust air in comparison to filtering a gas escaping a dissolving bath. This allows cost savings in terms of dimensioning of the filter system and their operating costs.

The advantages of the invention over the prior art can be seen particularly clearly in the following comparisons.

Thus, a charge amount of 6,000-7,000 Ah in a chromium process with an electrolyte temperature of 65-70 ° C and a chromic acid concentration of about 300 g / ltr, for example, for the separation of electrolytes, an exhaust air volume of 12,000-20,000 cbm / h in conventional exhaust air technology. The required process basin holds about 10-13 cbm chromic acid. This results in about 50 amp / qdm × about 140 qdm = ca 7,000 amp = 0.5 amp / ltr of electrolyte power to hydrogen and oxygen gases that must be removed and cleaned as aerosols, according to a washer size including fan of approx. 10-12 cbm or 0.5 amp of power / cbm of exhaust air / h.

If the gas escapes the dissolving bath, the performance values are even greater in a design according to the prior art.

In the case of a device according to the invention carrying out a method according to the invention, on the other hand, there is an exhaust air quantity of just 300-500 cbm / h, corresponding to an electrolyte volume of chromic acid of 500-800 ltr at 7000 amph. Accordingly, a device according to the invention achieves a substantially higher power density and is therefore many times more economical than a device according to the prior art.

The pickling of Aluminiumpressmatrixen according to a conventional method for all aluminum pressing plants at 90 ° C in alkali solution results in a high formation of electrolytes by dissolution of aluminum with strong hydrogen formation. According to the state of the art, the filter systems must treat an exhaust air volume of approx. 8,000-10,000 cbm of exhaust air / h. In a gas separation according to the invention under reduced pressure in a closed gas separation space, the amount of exhaust air to be treated drops to about 500 cbm exhaust air / h.

The invention is particularly applicable industrially in the production of galvanic coatings.

LIST OF REFERENCE NUMBERS

01

contraption

02

process space

03

reactor chamber

04

supply

05

derivation

06

arrow

07

Gas separation space

08

Electrolyte level in the gas separation space 07

09

conveyor

10

circulation

30

Electrolyte level in the reactor room 03

70

inlet mouth

71

drain mouth

72

Gasphasenausleitungsmündung

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• EP 0445120 B1 [0009]
• JP 06180000 A [0010]

Claims (11)

Process for the production of electroplated coatings, wherein: - an electrolyte in communication with an initial or sacrificial material ( 10 ) circulates, - in the circuit ( 10 ) is dissolved in the electrolyte starting or sacrificial material as a galvanic coating on a workpiece, which is arranged as a cathode electrically contacted in the electrolyte, is deposited, - in the direction of circulation ( 06 ) in the circuit ( 10 ), before the dissolved in the electrolyte starting material or sacrificial material is deposited as a galvanic coating on a workpiece, while the galvanization is formed in the circuit emerging gas together with this mitbeförderte electrolytes from the electrolyte, - then the entrained gas entrained electrolytes are filtered , and - the remaining, separated from the electrolyte gas from the cycle ( 10 ) Will get removed. The method of claim 1, wherein the filtered electrolytes are returned to the electrolyte storage tank. A method according to claim 1 or 2, wherein the gas produced during the galvanization, in addition to the electrolyte carried along with it, is separated from the electrolyte under a negative pressure relative to an environment outside the circuit ( 10 ) is deposited. The method of claim 1, 2 or 3, wherein at least the deposition of the sacrificial material or sacrificial material on a workpiece, which is arranged in the electrolyte, under a negative pressure at least against an environment outside the circuit ( 10 ) he follows. Method according to one of claims 1 to 4, wherein the gas separation at a highest point of the circuit ( 10 ) happens. Contraption ( 01 ) for producing galvanic coatings which comprise at least one process space ( 02 ), in which at least one to be provided with a galvanic coating workpiece and an electrolyte can be introduced or introduced, which communicates with a soluble therein, the material for the coating making available starting or sacrificial material, and a reactor space ( 03 ), in which the starting material or sacrificial material is introduced into the electrolyte and which is supplied via a supply line ( 04 ) and via a derivative ( 05 ) with the process space ( 02 ) and the part of a cycle ( 10 ) with reactor space ( 03 ), Supply line ( 04 ), Process space ( 02 ) and derivation ( 05 ) is, in which cycle ( 10 ) circulates the electrolyte, wherein in the circuit ( 10 ) a gas separation space ( 07 within which the electrolyte has a surface with an electrolyte mirror ( 08 ) above which electrolyte level ( 08 ) there is a trap for gas arising in the electrolyte during the galvanization, or which gas separation space ( 07 ) with the circuit ( 10 ) communicates, so that during the production of galvanic coatings in the electrolyte resulting gas from the electrolyte in the gas separation space ( 07 ) escape and thereby the cycle ( 10 ) can be removed. Device according to claim 6, wherein at least during the production of galvanic coatings at least in the gas deposition space ( 07 ) a negative pressure to a pressure in an environment outside the circuit ( 10 ) prevails. Apparatus according to claim 7, wherein the negative pressure in the gas separation space ( 07 ) at least in part by removal in the gas separation space ( 07 ) collected gas from the gas separation space ( 07 ) is made. Apparatus according to any one of claims 6 to 8, wherein electrolytes entrained in the separated gas are filtered. The device of claim 9, wherein the filtered electrolytes are returned to the electrolyte. Device according to one of claims 6 to 10, wherein in the direction of circulation ( 06 ) of the electrolyte in the circuit ( 10 ) seen the gas separation space ( 07 ) after the reactor space ( 03 ) and in front of the process room ( 02 ) is arranged.

Images