DE102012000899A1 - Dosing device for providing liquid component within framework for wet-chemical treatment of workpieces to be used, comprises an accumulator, a supply line, weighing device, flow measuring unit, controllable outlet valve, and discharge line - Google Patents

Abstract

Dosing device (1) comprises: an accumulator (2) with an inlet (3) and an outlet (4); at least one supply line (5) opening into the accumulator; a weighing device for the accumulator; a flow measuring unit arranged downstream of the outlet; at least one controllable outlet valve; and a discharge line. The accumulator comprises an inlet for pressurized gas and the outlet is arranged in a bottom portion of the accumulator. Independent claims are also included for: (1) a treatment station for wet chemical treatment of workpieces using a treatment medium having at least one liquid component, comprising a treatment tank, a medium supply line, which terminates in the treatment tank, and at least one dosing device with at least one supply line and a discharge line, where the supply line is fed using a corresponding component supply line, and the discharge line opens in the medium supply line; (2) a treatment plant for wet-chemical treatment of workpieces, comprising at least one treatment station; and (3) providing the liquid component within the framework for the wet-chemical treatment of workpieces to be used, using the above dosing device, comprising (a) supplying the component into the accumulator using the supply line, (b) at least partially filling the accumulator with the component, (c) supplying a stationary gas above the component at the residual volume of the accumulator, under pressure, (d) degassing and soothing the component present in the accumulator, (e) determining the amount of the component present in the accumulator, (f) opening an outlet valve and detecting the amount of component flowing under pressure from the accumulator via the outlet valve and the subsequent discharge passage using flow measuring device, (g) closing the outlet valve, when the amount has flowed equal to a preset target amount, (h) determining the quantity of the component present in the accumulator, calculating the difference of the amount present in the accumulator before opening of the outlet valve, and comparing the difference with the preset target amount, where a deviation between the calculated difference and the target amount generates an error signal.

Description

introduction

The invention relates to the field of metering devices. In particular, the invention relates to the field of metering devices for liquid components to be used in the course of a wet-chemical treatment of workpieces, as well as to a treatment system with such a metering device.

State of the art and disadvantages

The fabrication of articles such as solar cells or semiconductor devices typically involves one or more wet chemical processing steps such as ablation (eg, etching), surface modifying (eg, doping), coating (e.g., metallizing), or cleaning (e.g. Rinsing) of substrates which often comprise or consist of silicon, glass, ceramic, epoxy or plastic. Since in the majority of cases several such wet chemical treatment steps follow one another, corresponding systems are offered on the market which have at least one, but usually a plurality of successive wet-chemical treatment stations, also referred to below as "stations" for short. The material to be treated is conveyed from one station to the next either in batch mode or in inline. For economic reasons, the stations are already standardized as far as possible in terms of their dimensions, to be easily replaceable when a station fails or a new process is to be put together. The wet-chemical treatment is typically carried out in a treatment basin assigned to the station. Such treatment systems are also sold by the applicant under the name "NIAK".

Naturally, each of the wet chemical treatment stations such a system with one or more media such. B. (DI) water, etching liquid (acid or alkali), electrolyte, etc. are supplied. For this purpose, it is necessary to dose the finished compiled treatment medium or components thereof in the correct amount in the pelvis. A high prescription loyalty is indispensable for consistently good treatment results.

For this purpose, the component supply lines, which carry the liquid components (also referred to below as "liquid"), are connected to so-called metering devices. Usually, the amount of liquid to be dispensed is detected by a single controller. Such control devices are known from the prior art and available for a wide variety of tasks. However, if such a control device gives off erroneous quantities, this will only, if at all, be noticed after a long time due to worsening treatment results. The localization of the error is complex and leads to long downtime of the entire system, which is undesirable.

In addition, it is often necessary to provide both small and large quantities with sufficient accuracy, with known metering devices being either accurate but slowly metering, or capable of rapidly metering larger quantities, but unsuitable or at least inaccurate for a small amount.

Typically, each treatment station also includes specific metering devices, controllers, and the like for the media or components thereof. As a result, such a station includes a large number of metering devices along with fluid lines, which are typically routed and connected "as needed". For connection to a central component supply, a not exactly defined area is kept free on the underside, the back and / or the top of a station. Accordingly, when assembling a plant from individual stations, the connection situation of each station must be considered separately, which is both time-consuming and can be a source of connection errors.

Frequently, some or all of the dosing or operating elements of a station, for example, for maintenance, to be replaced. Even a media exchange may make it necessary to clean all fluid lines, valves, etc. of a medium or even replace. This means that at least the entire station, and possibly even the entire system must be taken out of service for a longer period of time, since the often present in a variety of fluidic components must all be removed individually and maintained separately. Analogously, this also applies to electrical components such. B. sensors or gauges.

Object of the invention and solution

The object of the invention is therefore to provide a device which avoids the disadvantages of the prior art.

The invention is intended to provide a metering device which allows a quick and safe metering of small and large amounts of a liquid component of a treatment liquid, and with which maintenance Downtime of a treatment station, with which it is associated, and / or a treatment facility, which are associated with the metering device and / or the treatment station to minimize.

For this purpose, the metering device should allow the simplest possible detection of measurement errors in the determination of the amount of a liquid component to be metered.

Furthermore, the invention should shorten the time required to connect a metering device to a station and / or plant, thereby reducing or avoiding connection errors. Also, the invention should reduce the cost of maintenance or replacement of particular fluidic components of a station and shorten the time required for this.

The object is achieved by a metering device according to claim 1, a treatment plant according to claim 8, and a method according to claim 12. Further advantageous embodiments are given in the dependent claims, the description and the figures.

description

First, the metering device according to the invention will be described. Subsequently, the description of a treatment plant according to the invention, as well as the method according to the invention.

The metering device according to the invention serves to provide a liquid component of a treatment medium to be used as part of a wet-chemical treatment of workpieces. The metering device comprises a reservoir with (at least) one inlet and (at least) one outlet, at least one feed line for the medium or a component thereof, a weighing device for the storage contents, a flow measuring device arranged downstream of the outlet, at least one controllable outlet valve , as well as a discharge line. According to the invention, the store has an inflow for preferably inert compressed gas, and the outlet is arranged in the lower area of the store.

The liquid component may be, for example, an etching medium, a cleaning liquid, or a transport liquid such as in particular water. The memory is used for temporarily storing the liquid component, which can flow from an external reservoir via the supply line into the memory. Preferably, a Hauptabsperrventil is in the region of the inlet. In addition, the memory is used to calm the liquid component flowing into it. It can therefore also be referred to as "Entpulsationsstrecke". In particular, bubbles which form when flowing in should, preferably before the measurement and the forwarding of the component, have been removed from the liquid. This is done by rising the bubbles to a region above the liquid level within the reservoir.

The weighing device serves to determine the amount of the component contained in the memory. For this purpose, the empty weight of the memory is deducted from its current weight. This difference corresponds to the amount by weight of the component contained in the memory. It is clear that other measuring devices serving to detect the amount of liquid contained in the memory may also be suitable.

By means of the flow measuring device, the amount of the memory leaving component is detected. Preferably, this device has a density and temperature compensation, so as to achieve the most accurate measurement result.

The at least one exhaust valve is for the controlled discharge of a portion of the memory contents. It is located downstream of the storage and thus before or preferably behind the flow meter.

It can pressurize the interior of the reservoir via the pressure gas feed. It will be appreciated that the pressurized gas is preferably an inert gas so as not to chemically alter the component in the reservoir. When the exhaust valve is opened, the excess pressure of the pressurized gas forces the liquid component underneath out of the reservoir, provided the exhaust valve is open. In this way, a very fast dispensing of the liquid is guaranteed. In addition, the compressed gas compresses the possibly contained in the liquid gas bubbles, so that they do not constitute a source of error in the context of a volumetric or magnetic-inductive measurement. In addition, the increased pressure of a faster calming of the liquid, since it often flows in pulsating and / or turbulent flow. Thus, delivery by means of compressed gas offers a number of advantages over prior art devices, which employ either gravity or (often pulsating piston) pumps.

The outlet is located at the bottom of the reservoir, as it is at most far from the surface of the liquid contained in the reservoir, above which the ascended gas bubbles collect. In addition, the gas bubbles remove automatically due to their low density of the Area of the outlet. This is advantageous because it is not desirable to dispense the gas bubbles.

Such a metering device has the advantage that it allows in a simple manner the control of the quantity value detected by means of the flow measuring device, in that once the liquid has been dispensed, a determination of the quantity contained in it takes place again. If these values do not match, there is a faulty measurement, which is displayed in the simplest case via a warning light, so that countermeasures can be initiated. Tedious troubleshooting is eliminated if the insufficient treatment result is based on a metering measurement error. In fact, this error is already visible long before there are inadequate treatment outcomes, which saves both time and costly waste.

According to a preferred embodiment of the metering device, the inflow for the compressed gas in the upper region of the memory is arranged. In this way, a blistering by inflowing pressurized gas is prevented. In addition, it may be provided to pressurize only a part of the surface of the liquid with compressed gas, while another part of the surface, which is separated by means of a vertical, open at the bottom partition, is essentially not acted upon by compressed gas. By appropriate guides thus ascending gas can be discharged into a different space as in the room, which is in communication with the inflow of the compressed gas.

According to a further embodiment, a pressure equalization section is arranged upstream of the inflow. This serves for the preparation of the compressed gas with regard to a pressure which is suitable for the accumulator, since the compressed gas source (eg a compressed gas cylinder) may provide a significantly higher pressure than the accumulator is capable of receiving. Furthermore, the pressure compensation line may include a pressure monitor, a pressure valve and / or a condensate separator and drain. Preferably, these components are combined in a valve terminal.

According to a further embodiment, the memory is further associated with a device for detecting the accumulator pressure and / or a pressure relief valve. In this way, a harmful to the memory overpressure can be detected in good time and, preferably automated, drained, before actually causing damage. Since the discharge rate of the liquid depends on the pressure of the store, the pressure can be lowered to a predetermined storage pressure leading to a desired discharge rate via the valve if necessary.

According to another embodiment, the metering device has a plurality of outlet valves for metering different component quantities. These exhaust valves are preferably integrated into a common housing, so that, according to an alternative formulation, an exhaust valve with a plurality of outlet openings for different discharge rates can be provided. The advantage of this embodiment lies in the more accurate metering (and thus recipe fidelity) of both small (eg 5 ml / s) and large (eg 400 ml / s) delivery rates, with the smaller delivery rate over a smaller diameter exit port he follows.

Particularly preferably, the memory has a volume of 10 liters. Such a volume is sufficient for the typical dosing tasks in the context of wet-chemical treatment plants, and at the same time requires only minimal installation space.

According to a further embodiment, the metering device comprises an evaluation and control unit connected to the weighing device, the flow measuring device and the at least one outlet valve. This evaluation and control unit is used to process the result of the weighing process, the comparison of the result with the result of the flow measurement, the control of the at least one exhaust valve and optionally the output of an error signal, if the comparison results in a deviation between weight and flow measurement. It is clear that, if necessary, a conversion of the values must take place in such a way that they are comparable; for example, from the flow rate and the time in which the exhaust valve is opened, the amount discharged can be closed.

According to a preferred embodiment, the at least one supply and discharge line open in each case a quick connector (in short: quick connector). Such a quick connector serves the particularly time-saving, yet safe connection of fluidic lines by means of special connections. This can z. B. self-sealing plug connections or bayonet connections. Particularly preferably, these connections are combined in a dedicated connection area of the metering device. It is clear that corresponding counterparts are to be provided on the structural unit to which the metering device is assigned and to which it is to be connected.

It will be appreciated that such quick connectors need not be limited to fluid interfaces, but may include, for example, the field of electrical or mechanical connections.

According to a further embodiment, the metering device further comprises a control panel and / or a local control unit. The control panel serves to combine control and display components, which should be accessible from the outside, for example by an operator. The local control unit serves as an interface to a higher-level central control, which is part of a treatment station or treatment facility.

The invention also discloses a treatment station for the wet-chemical treatment of workpieces by means of a treatment medium having at least one liquid component. Such a station comprises a treatment basin for receiving the treatment medium, a media supply line ending in the treatment basin, and at least one metering device, which is particularly preferably designed according to one of the preceding claims. According to the invention, the metering device has at least one supply line and a discharge line. The at least one supply line of the metering device can be fed by means of a corresponding component supply line, and the discharge line of the metering device opens into the media supply line. Since the treatment station comprises only one treatment basin, it serves to carry out a treatment step (eg etching or cleaning the workpiece).

The component supply line is used to provide the liquid component, which is to be entered by means of the dosing unit according to the invention in the treatment basin of the treatment station according to the invention.

Since the discharge line of the metering device opens into the media supply line, which in turn terminates in the treatment basin, one or (if several metering devices are present) a plurality of components can be mixed into the treatment basin in a recipe-faithful manner. Alternatively, dosing (and thus mixing) into a common mixing line connected to all metering devices, which in turn ends in the basin, is also possible. Finally, it is also possible that each metering module has a plurality of discharge lines, each of which opens into a different basin. In this case, each metering device has a corresponding number of exhaust valves, and / or additional valves are provided, which are arranged immediately before the outflow to the tank.

A treatment station provided with a metering device preferably designed in accordance with the above description has a number of advantages. Thus, the recipe-faithful dosing of small and large quantities is guaranteed, errors in the dosage are detected early, and the replacement of the dosing unit, for example for maintenance is possible in a quick and easy way. For this purpose, it is particularly preferred that the metering unit is designed as a metering module, which is vorhaltbar in plurality and therefore exchangeable without significant loss of time. Another advantage is the small size and more compact design of such an optimized module. This, in turn, also has a positive effect, for example, on the exhaust air problem existing in wet-chemical plants, since a more compact and particularly preferably enclosed (closed) module offers less attack surface for the condensation of the often corrosive gases present in such systems.

However, even in the case of a metering device other than that described above, the treatment station has the advantage that, because of the metering device (s) associated with it, a smaller number of connection points to a treatment system comprising the treatment station (s) is required. In addition, the installation or replacement of such an "integrated" station is easier and faster to accomplish, since not yet one or more separate metering devices are to be replaced with.

The invention further discloses a treatment plant for the wet-chemical treatment of workpieces, comprising at least one treatment station as defined above. In other words, the treatment plant comprises (typically more than) a treatment station, wherein this treatment station (s) have at least one metering device, and particularly preferably the metering device according to the invention.

In other words, each treatment station (and thus each treatment basin) is associated with a number of metering devices corresponding to the number of components required in that basin.

If any metering device is used, the treatment plant has the advantages of using a standardized metering module. If the dosing module according to the invention is used, the further advantages already set forth above result.

Finally, the invention discloses an advantageous treatment plant. This has via media supply lines feedable treatment basins for wet-chemical treatment of workpieces by means of a treatment medium. The treatment medium in turn has at least one, and typically several, liquid components. Also, the treatment plant comprises at least one, an individual discharge line having metering device, the preferred, but not mandatory, the metering device according to the invention corresponds.

According to the invention, an individual metering device is now assigned to each liquid component required for the treatment as part of the entire system. This means that such a system no longer has metering devices which are assigned to the individual treatment stations, but that each of the liquid components to be used in the context of the system is metered by means of an individual metering device. This drastically reduces the number of dosing devices required as compared to the system described above; especially when a plurality of basins is to be supplied with a manageable number of components.

In order to be able to meter specific types and quantities of the components into the individual treatment tanks via the metering devices assigned to the system (and no longer to the treatment stations), each discharge line of each metering device is connected to the media supply lines of the treatment tanks via a controllable changeover valve. Thus, it can be individually controlled which amount of which component should be dosed into which treatment tank of the system.

According to an alternative embodiment, the system has no switching valve, but each discharge line opens into each treatment basin and comprises a selector valve, which is controllable and only open when a component is actually to be dosed in this same treatment tank. The amount is determined via the dosing unit associated with the component, and the location via the respective selector valve.

It is clear that with preferred use of one or more metering devices according to the invention, the advantages set out above also result in an analogous manner, but their repetition should be dispensed with in the present case.

Particularly preferably, the components and media supply line (s) of such a treatment system end up in receptacles for supply and discharge lines of the metering device (s) opening in quick connections. In other words, the treatment plant can be connected to the metering device (s) by means of appropriate quick connections already mentioned above.

Likewise particularly preferably, the treatment installation has at least one recess for the at least one dosing module which can be pushed into it. This means that the treatment plant is suitable for receiving standardized dosing modules designed to be insertable into the installation, which are thus exchangeable in a particularly time-saving manner; in particular when quick connections described above are provided. Such a standard may relate in addition to the geometry in particular to the connection points for fluid, electrical or other interfaces.

• – Zuführen der Komponente mittels der Zuführleitung in den Speicher: Die flüssige Komponente wird, bevorzugt über ein hierzu geöffnetes Hauptabsperrventil, in den Speicher eingelassen.
• – mindestens teilweises Auffüllen des Speichers mit der Komponente: Der Speicher wird mit der Komponente aufgefüllt, wobei das sich oberhalb des Flüssigkeitspegels sammelnde Gas nach außen abgeführt oder in ein gesondertes Behältnis eingepresst wird. Es ist klar, dass hierzu im Speicher ein gesonderter Abfluss vorhanden sein muss, der bevorzugt in seinem oberen Bereich angeordnet ist.
• – Beaufschlagen des oberhalb der Komponente verbliebenen Restvolumens des Speichers mit einem unter Druck stehenden Gas: Druckgas wird über einen Zufluss in den Speicher geleitet. Das Gas ist bevorzugt ein Inertgas wie z. B. Stickstoff. Es dient unter anderem dem Ausbringen der Flüssigkeit (s. u.).
• – Entgasen und Beruhigen der im Speicher enthaltenen Komponente: Gasblasen werden aus der Flüssigkeit entfernt, indem diese nach oben aufsteigen und sich ggf. mit dem dort vorhandenen Druckgas vermischen. Aufgrund einer gewissen Verweilzeit kommt die Flüssigkeit zur Ruhe; dies kann durch konstruktive Maßnahmen wie z. B. eine Schaum- oder Netzstruktur, die im Speicher eingelegt ist, unterstützt werden.
• – Bestimmen der Menge der im Speicher enthaltenen Komponente: Mittels einer geeigneten Messeinrichtung wird die im Speicher enthaltene Flüssigkeitsmenge bestimmt. Dies kann direkt (z. B. mittels Füllstandsmessung bei bekannter Geometrie des Speichers) oder indirekt (z. B. mittels Wägens) geschehen.
• – Öffnen eines Auslassventils und Erfassung der Menge der unter Druck aus dem Speicher über das Auslassventil und die daran anschließende Abführleitung abfließenden Komponente mittels der Durchflussmesseinrichtung: Das Öffnen geschieht bevorzugt programmgesteuert, beispielsweise zum initialen Befüllen eines Beckens, oder bedarfsgesteuert, beispielsweise zum Nachfüllen einer bestimmten Menge im Rahmen der Behandlung verbrauchter Komponente.
• – Schließen des Auslassventils, wenn die abgeflossene Menge einer voreingestellten Sollmenge entspricht: Die Sollmenge wird vorgegeben oder laufend ermittelt (s. vorherigen Absatz).
• – Bestimmen der Menge der im Speicher verbliebenen Komponente, Berechnung der Differenz zur vor dem Öffnen des Auslassventils im Speicher enthaltenen Menge, und Vergleich dieser Differenz mit der voreingestellten Sollmenge: Mittels einer Differenzbestimmung kann festgestellt werden, ob die mittels der Durchflussmesseinrichtung erfasste Flüssigkeitsmenge der Menge entspricht, die tatsächlich aus dem Speicher abgeflossen ist.

The process according to the invention will be described below. This serves to provide a liquid component to be used as part of a wet-chemical treatment of workpieces using a metering device as defined above, and comprises the following steps:

• - Supplying the component by means of the supply line in the memory: The liquid component is, preferably via a main shut-off valve open, admitted to the memory.
• - At least partially filling the memory with the component: The memory is filled with the component, wherein the above the liquid level collecting gas is discharged to the outside or pressed into a separate container. It is clear that for this purpose in the memory a separate drain must be present, which is preferably arranged in its upper region.
• - Applying to the remaining volume of the memory above the component with a pressurized gas: compressed gas is passed through an inlet into the memory. The gas is preferably an inert gas such as. Nitrogen. Among other things, it serves to dispense the liquid (see below).
• - Degassing and calming the component contained in the memory: Gas bubbles are removed from the liquid by rising upwards and possibly mixing with the pressure gas present there. Due to a certain residence time, the liquid comes to rest; This can be achieved by constructive measures such. B. a foam or network structure, which is inserted in the memory to be supported.
• - Determining the amount of the component contained in the memory: By means of a suitable measuring device, the amount of liquid contained in the memory is determined. This can be done directly (eg by means of level measurement with known geometry of the memory) or indirectly (eg by weighing).
• - Opening an exhaust valve and detecting the amount of under pressure from the memory via the outlet valve and the subsequent discharge line effluent component by means of the flow measuring device: The opening is preferably done programmatically, For example, for the initial filling of a basin, or as needed, for example, to replenish a certain amount in the context of the treatment of spent component.
• - Closing of the outlet valve if the amount drained corresponds to a preset target quantity: The target quantity is specified or continuously determined (see previous paragraph).
• - Determining the amount of remaining in the memory component, calculating the difference to the amount before the opening of the exhaust valve contained in the memory, and comparing this difference with the preset target amount: By means of a difference determination can be determined whether the amount of liquid detected by the flow meter corresponds to the amount that actually leaked from the store.

In the case of a deviation between the calculated difference and the set quantity, an error signal is generated according to the invention. This can be a warning or a control signal for a downstream control. It can be determined a correction factor for the flow measuring device, so that now correct amounts are output via the exhaust valve. In the simplest case, an operator may calibrate the scale or flow meter, depending on which device is the source of the error. In this respect, therefore, a mutual control of the two measuring devices takes place.

Preferably, the pressure in the memory is measured by means of a suitable device, and when a maximum pressure is exceeded, a pressure relief valve is opened until the pressure has fallen below the maximum pressure. In this way, the memory is protected from being damaged by excessive pressure of the compressed gas, or by outgassing or expanding liquid.

As already mentioned in the description of the metering device according to the invention, the determination of the amount of the component contained in the memory is preferably carried out by weighing the memory and forming the difference between its current and its empty weight. The measurement result of the weighing process is largely independent of the temperature of the component, or the amount of gas bubbles contained in it. Particularly preferably, the degassing takes place by means of ascending the gas bubbles contained in the component into a collecting volume provided within the store and above the liquid level of the component. In other words, above the liquid, a residual volume is kept free, in which on the one hand, the compressed gas flows, and in which on the other hand, the gas bubbles can rise.

It is further preferred that, depending on the desired amount to be dispensed, such as in particular 5 and 400 ml / s different outlet valves are present and are controlled. It is clear that these valves can be housed in a common housing. The advantage of this approach is that so constructive to the needs of a fast application of a large amount or the highly accurate application of a small amount of liquid can be considered.

Finally, according to a further preferred embodiment, the method according to the invention provides that, when a minimum quantity of the component contained in the reservoir is undershot, a shut-off valve is opened. In this way it can be ensured that the memory does not dry out. Particular preference is given to determining the amount of the preferably existing weighing device, or a float or the like used.

According to a particularly preferred embodiment for a treatment plant with a number of metering devices corresponding to the number of liquid components (see above), the (metered) component flowing out of an individual metering device flows into a discharge line which opens into a plurality of treatment tanks. The selection of the treatment tank to be filled is then carried out by driving a selector valve, which is arranged in the desired basin associated mouth portion of the discharge line. It is clear that each pelvis and metering device a controllable selection valve must be present so that each component is selectively dosed into each pelvis. It is also clear that in special cases, in which certain basins of a system must be supplied with a certain component at any time, there must be no mouth of the discharge line and no selector valve there.

It is further clear that this method is also applicable to other than the metering device according to the invention, described above.

The metering device according to the invention enables a fast and reliable metering of small and large quantities of a liquid component of a treatment liquid.

The invention also makes it possible to minimize maintenance-related downtimes of a treatment station, which is associated with the dosing unit according to the invention, and / or a treatment facility, which are associated with the metering device and / or the treatment station, by a simple detection of measurement errors in the determination of allows metered amount of a liquid component, and thereby reduces connection errors during maintenance or avoids.

figure description

1 shows a particularly preferred embodiment of the metering device according to the invention.

2 shows a treatment plant with several dosing modules.

3 shows an alternative treatment plant with multiple dosing modules.

According to the 1 , which is a metering device according to the invention 1 points, points the memory 2 an inlet 3 and an outlet 4 on. Via a supply line 5 can through the inlet 2 the metered, liquid component F in the memory 2 incorporated. For this purpose, a (main) shut-off valve 6 provided, which must be opened to the inlet.

The memory 2 is to a weighing device 7 coupled with the weight of the memory 1 including the liquid component F 'contained therein is detectable. This device is in the 1 schematically represented by a spring balance.

Gas bubbles present in the liquid F '(without reference numeral) can ascend (small arrows) and accumulate in the upper region 2 ' of the memory 2 , They thus automatically move away from the outlet 4 , in the largely bubble-free, lower area 2 '' of the memory 2 is arranged.

The outlet 4 flows into a flow measuring device 8th with which the outflowing amount (or a related value, in particular the flow rate) of the liquid component can be determined. Via an outlet valve 9 the now metered component F "leaves the metering device 1 via a discharge line 10 ,

The memory 2 also points in its upper area 2 ' an inflow 11 for pressurized gas G on. This compressed gas G is preferably via a pressure equalization section 12 , which serves to condition the compressed gas G, provided. For reasons of clarity, their components, in particular an inflow valve, are not shown.

The control of the components of the dosing unit 1 takes place by means of an evaluation and control unit 13 connected via control lines (dashed lines, without reference numerals) to the shut-off valve 6 , the weighing device 7 , the flow measuring device 8th and the exhaust valve 9 connected is. The evaluation and control unit 13 is preferably by a parent, a treatment plant associated control unit (each not shown) controllable.

The 2 schematically shows a treatment plant 14 containing a number of treatment tanks 15 includes. In addition, it has two metering devices 1 . 1' on. The treatment tanks 15 are via media supply lines 16 be fed with a treatment medium B. This consists of several components F, which are in individual tanks 16 be kept. Each tank is over a component supply line 19 with a metering device provided for the corresponding liquid component F. 1 . 1' fluidly connected. Thus, everyone is, for treatment in the context of the entire system 14 required, liquid component F an individual metering device 1 . 1' assigned.

Each metering device 1 . 1' has an individual discharge line 10 . 10 ' on. Furthermore, each discharge line 10 . 10 ' each metering device 1 . 1' via a controllable changeover valve 17 connected to the media supply lines of the treatment tank. This allows individual control of the amount of a particular component in a particular treatment tank of the plant. Not shown is a central control of the system 14 connected to the controllable diverter valve 17 must be connected, and the local evaluation and control devices (not shown) of the metering devices 1 . 1' controls, so that these the desired amount of the desired liquid component F in the discharge lines 10 . 10 ' dosing.

In the 3 is an alternative embodiment of the above treatment plant 14 shown. For the sake of clarity, a description of already explained features will be omitted. in contrast to the preceding embodiment, the system shown here 14 no controllable diverter valve, but each discharge line 10 . 10 ' flows into every treatment basin 15 and includes a selector valve 9 ' (only on the left in the picture provided with reference numerals). This is controllable and only opened, if indeed a component F '' in this same treatment tank 15 should be dosed. The amount is about the component F associated dosing unit 1 . 1' determined, and the place (and thus the basin) via the respective selector valve 9 ' , Again not shown is the higher-level control and the control lines, which in this case also to the selector valves 9 ' have to reach. It is possible on the outlet valves (not shown) of the metering units 1 . 1' to dispense with their functions through the selector valves 9 ' be taken over.

LIST OF REFERENCE NUMBERS

1, 1 '

metering

2

Storage

2 '

upper area

2 ''

lower area

3

inlet

4

outlet

5

feed

6

shut-off valve

7

weighing

8th

Flow meter

9

outlet valve

9 '

selector valve

10, 10 '

discharge

11

inflow

12

Pressure equalization path

13

Evaluation and control unit

14

Treatment plant, plant

15

treatment tank

16

tank

17

controllable changeover valve

18

Component supply line

19

Media supply line

F

liquid component

F '

memory component / remaining component, memory contents

F ''

metered component, amount drained off

G

Compressed gas, gas

B

treatment medium

Claims (16)

Dosing device ( 1 . 1' ) for providing a liquid component (F) to be used as part of a wet-chemical treatment of workpieces, comprising a memory ( 2 ) with an inlet ( 3 ) and an outlet ( 4 ), at least one in the memory ( 2 ) feed line ( 5 ), a weighing device ( 7 ) for the storage contents (F '), one downstream of the outlet ( 4 ) arranged flow measuring device ( 8th ), at least one controllable outlet valve ( 9 ), as well as a discharge line ( 10 . 10 ' ), whereby the memory ( 2 ) an inflow ( 11 ) for pressurized gas (G) and the outlet ( 4 ) in the area below ( 2 '' ) of the memory ( 2 ) is arranged. Dosing device ( 1 . 1' ) according to claim 1, wherein the inflow ( 11 ) for the compressed gas (G) in the upper area ( 2 ' ) of the memory ( 2 ) is arranged. Dosing device ( 1 . 1' ) according to claim 1 or 2, wherein upstream of the inflow ( 11 ) a pressure equalization section ( 12 ) is arranged. Dosing device ( 1 . 1' ) according to one of claims 1 to 3, wherein the memory ( 2 ) Further associated with a device for detecting the accumulator pressure and / or a pressure relief valve. Dosing device ( 1 . 1' ) according to one of the preceding claims, which comprises a plurality of exhaust valves ( 9 ) having. Dosing device ( 1 . 1' ) according to any one of the preceding claims, which further comprises one with the weighing device ( 7 ), the flow measuring device ( 8th ) and the at least one outlet valve ( 9 ) connected evaluation and control unit ( 13 ). Dosing device ( 1 . 1' ) according to one of the preceding claims, wherein the at least one supply and discharge line ( 5 . 10 . 10 ' ) in each case open a quick connector. Treatment station for the wet-chemical treatment of workpieces by means of a treatment medium (B) having at least one liquid component (F) comprising a treatment basin ( 15 ), one in the treatment basin ( 15 ) ending media supply line ( 19 ), and at least one metering device ( 1 . 1' ) with at least one supply line ( 5 ) and a discharge line ( 10 . 10 ' ), this supply line ( 5 ) by means of a corresponding component supply line ( 18 ) is fed, and their discharge line ( 10 . 10 ' ) into the media supply line ( 19 ). Treatment plant ( 14 ) for the wet-chemical treatment of workpieces, comprising at least one treatment station as defined in claim 8. Treatment plant ( 14 ) with via media supply lines ( 19 ) supplyable treatment tanks ( 15 ) for wet-chemical treatment of workpieces by means of a treatment medium (B) having at least one liquid component (F), with at least one, an individual discharge line ( 10 . 10 ' ) having metering device ( 1 . 1' ), each one for treatment throughout the Annex ( 14 ), liquid component (F) an individual metering device ( 1 . 1' ) and each discharge line ( 10 . 10 ' ) via a controllable changeover valve ( 17 ) with the media supply lines ( 19 ) of treatment tanks ( 15 ), or wherein each discharge line ( 10 . 10 ' ) in each treatment tank ( 15 ) and includes a selector valve. Treatment plant ( 14 ) according to claim 10, wherein its component and media supply line (s) ( 18 . 19 ) in receptacles for incoming and outgoing lines in quick connections ( 5 . 10 . 10 ' ) of the metering device (s) ( 1 . 1' ) and / or wherein the treatment plant ( 14 ) at least one recess for the insertable into it at least one metering module ( 1 . 1' ) having. Method for providing a liquid component (F) to be used as part of a wet-chemical treatment of workpieces using a metering device ( 1 . 1' ) as defined in any one of claims 1 to 7, comprising the following steps: - feeding the component (F) by means of the supply line ( 5 ) in the memory ( 2 ); - at least partial filling of the memory ( 2 ) with the component (F); - Applying to the above the component (F) remaining volume of the memory ( 2 ) with a pressurized gas (G); - Degassing and calming the memory ( 2 ) contained component (F '); - Determining the amount of memory in memory ( 2 ) contained component (F '); - opening an exhaust valve ( 9 ) and detecting the amount of pressure from the reservoir ( 2 ) via the outlet valve ( 9 ) and the subsequent discharge line ( 10 . 10 ' ) effluent component (F '') by means of the flow measuring device ( 8th ); - closing the exhaust valve ( 9 ), when the amount of flow (F '') corresponds to a preset target amount; - Determining the amount of memory in memory ( 2 ) remaining component (F '), calculation of the difference to before the opening of the exhaust valve ( 9 ) In the storage room ( 2 ) and comparing this difference with the preset target amount; wherein an error signal is generated in the event of a deviation between the calculated difference and the setpoint quantity. The method of claim 12, wherein the pressure in the memory ( 2 ) is measured and when a maximum pressure is exceeded, a pressure relief valve is opened until the pressure has fallen below the maximum pressure. Method according to one of claims 12 to 13, wherein depending on the desired amount to be dispensed different exhaust valves ( 9 ) are present and are controlled. Method according to one of claims 12 to 14, wherein when falling below a minimum amount in the memory ( 2 ) contained component (F ') opening a shut-off valve ( 6 ) he follows. Method according to one of claims 12 to 15, wherein the outflowing component (F ') into a discharge line ( 10 . 10 ' ), which flows into several treatment tanks ( 15 ) and the selection of the treatment tank to be filled ( 15 ) by driving a in the mouth portion of the discharge line ( 10 . 10 ' ) arranged selector valve ( 9 ' ) he follows.

Images