EP2170606B1 - Filtration for printing presses - Google Patents

Abstract

A dampening solution circuit for a printing machine, includes a dampening unit, a dampening solution main reservoir, a dampening solution supply for feeding the dampening solution to the dampening unit from the dampening solution main reservoir and a dampening solution return for returning the dampening solution from the dampening unit into the dampening solution supply and a cleaning branch with a dampening solution cleaning apparatus is provided in the region of the dampening solution return, which cleaning branch is configured in such a way that during the operation of the dampening solution circuit a first dampening solution partial flow from the dampening solution main flow can be passed through the dampening solution cleaning apparatus, and the cleaning branch is connected in such a manner that the dampening solution cleaned in the dampening solution cleaning apparatus can be returned into the dampening solution supply.

Description

Field of the invention

The invention relates to a dampening solution circuit for a printing press and to a printing press with such a dampening solution circuit.

Background of the invention and prior art

In the prior art, dampening units are used in offset printing machines. The task of the dampening unit is to apply a dampening solution evenly to the printing plate of an offset printing press. The dampening solution is e.g. via a water box, nozzles or similarly applied to a first roller. A water film is applied as uniformly as possible by the roller over various other rollers on the printing plate of the printing press.

Excess dampening solution is usually collected, processed and fed to the dampening unit again.

Since, during operation, contamination of the fountain solution, e.g. As a result of color components and paper dust, the soiled dampening solution is generally removed, e.g. cleaned by filtration.

The DE 100 61 870 A1 discloses a cleaning system in which a feed pump removes fountain solution from a buffer and pumps the dampening water into a cleaning unit. In the cleaning unit, a further pump is provided, which presses the fountain solution through a pressure filter. According to the disclosure of this document, the entire dampening water flow through the Guided cleaning unit. Such a cleaning unit must therefore have a certain size and is relatively expensive to produce.

The JP 11 048459 describes a device for cleaning cleaning solution of a printing press with a separation tank with a regeneration device with a coarse filter and filter tanks.

Also known is a cleaning unit in which the fountain solution from a central tank, from which the printing units of a printing press are fed, is conveyed by means of a pump and passed through various cleaning devices. The cleaned fountain solution is returned to the central tank after cleaning. Such a device has the disadvantage that the fountain solution via a drain from the central. Tank must be promoted, which is regularly arranged in a certain area of the central tank and therefore only in this particular area withdrawing fountain solution, so that dampening water from other areas in the central tank proportionately guided to a lesser extent by the cleaning device and therefore not cleaned. This applies, for example, to the dampening water in the region of a dampening water level in the central tank, since the flow is generally arranged clearly below the dampening water level.

In the DE 103 60 051 A1 discloses a device in which contaminants, which have adhesive properties, are conveyed from a tank via what is known as a belt skimmer. This device has the disadvantage that only dirt with adhesive properties adhere to the tape and can be removed from the dampening solution via such a device.

There are still a variety of other devices known which are intended to solve common problems or offer detailed solutions. There is no particular general direction in the prior art that is common to different approaches. The technical development concerning the dampening solution supply of printing machines is not yet completed.

It is in the printing industry, especially in offset printing, the use of dampening solutions, which have an alcohol constituent, a problem, since such additives are considered harmful to health and the environment. One aim of the development is therefore to achieve a particularly economical use of fountain solution. In addition, during operation, larger amounts of dampening solution, which must be renewed at certain intervals, especially if they have soiling. The costs associated with disposal and renewal are considerable, so that even minor improvements in dampening solution supply make economic sense.

task

It is an object of the invention to provide a dampening solution circuit for a printing press and a printing press with such a fountain solution circulation, by means of which an effective handling of dampening solution is achieved.

Solution of the task

The object is achieved by the device according to the main claim 1. Advantageous embodiments are disclosed in the subclaims.

A first aspect of the invention relates to a dampening solution circuit for a printing press, the dampening solution circuit having at least one dampening unit, a fountain solution main container, a dampening solution supply and a dampening solution return, wherein the dampening agent supply between the fountain solution main container and the at least one dampening unit is arranged such that the at least one dampening unit dampening solution can be fed to the fountain solution main container via the dampening solution supply,
wherein the dampening solution return between the at least one dampening unit and the fountain solution main container is arranged such that dampening solution from the at least one dampening unit on the dampening solution return in the Dampening solution feed is traceable,
characterized in that the dampening solution circuit is designed such that a dampening main stream coming from the at least one dampening unit can be divided into a first dampening solution part stream and into a second dampening solution part stream, wherein the second dampening solution part stream can be generated temporally parallel and spatially separated from the first dampening medium part stream,
wherein in the range of dampening solution recycling, a cleaning branch is provided with a dampening solution cleaning device, which is designed such that during operation of the dampening solution circuit, the first dampening solution part stream from the fountain solution main stream through the dampening solution cleaning device is conductive, and
wherein the cleaning branch is connected to the dampening solution circuit in such a way that the dampening solution cleaned in the dampening solution cleaning device is traceable to the dampening solution supply, and
wherein the dampening solution circuit is designed such that the second dampening solution sub-stream without traversing the cleaning device is traceable into the fountain solution main container.

The phrase "traceable to the dampening solution supply" is to be understood as meaning that the dampening solution circuit is an open circuit, in the sense that the circulating dampening solution is continuously circulated during operation. Such a "return to the dampening solution supply" can be done directly or the dampening solution can be recycled at another point in the circulation such that the dampening solution passes on its subsequent path in the dampening solution supply. In the open circuit, a portion of the dampening solution can be transferred to the printing process, for example via the moistening during the printing process, and then usually can no longer be recycled. More dampening solution can be lost in the cleaning device, for example, the circulation. Such used dampening solution is preferably replaced in the circulation, wherein the dampening solution, which is fed to the fountain solution, is preferably checked for its quality. This is preferably done continuously. The term quality preferably includes one Composition of the dampening solution (for example, a water-alcohol ratio) and / or the temperature and / or the load with color particles and / or the like. In this case, the dampening solution circuit is preferably designed such that the monitoring and / or the control and control of the dampening solution quality and quantity takes place in the component of the dampening solution circuit, which is referred to herein as the fountain solution main container. The terms dampening solution main flow dampening solution part flow usually designate flow volumes per unit time. By splitting the dampening solution main stream into two dampening solution part streams, a targeted cleaning of one of the two dampening solution part streams and / or a separate treatment of the dampening solution part streams is possible.

A further advantageous embodiment relates to a dampening solution circuit in which the dampening solution recycling is designed such that no dampening solution pump is provided between dampening unit and dampening solution cleaning device. The term fountain solution pump primarily dampening means conveying devices are referred to, which are adapted to cause a pressure change in a volume unit in the dampening solution, which is adapted to promote the dampening solution to a different height level. Therefore, for example, conveyors in which only a negligible pressure difference is generated, in which, for example, the dampening solution is always exposed to the same atmospheric pressure as in an Archimedean spiral or other funding, which cause no turbulence in dampening solution. The fact that no such dampening solution pumps are provided in the inlet to the cleaning device, a turbulence of the dampening solution is avoided with the impurities contained in the dampening solution. Such turbulence has proved to be disadvantageous, since dampening and impurities can be emulsified by the turbulence and are difficult to separate from one another in the emulsified state. Surprisingly, it has been found that emulsification leads to a particularly disadvantageous intimate connection of the components when air is mixed with the dampening solution and the impurities. There are therefore particularly preferred no dampening solution before the cleaning device use, which are arranged such that during the pumping process air is stirred into the dampening solution. Pumps, which are arranged for example in the cleaning device itself and completely covered with fountain solution, and / or are so slow-rotating that an emulsification can be prevented, are therefore also not covered by the term dampening solution pump.

Also preferred is such a dampening solution circuit, which is designed such that the second dampening solution partial flow does not pass through a cleaning device on the way into the dampening solution supply. This has the advantage that the circulation of the Dampening solution circulation may have a high volume flow, without the cleaning device must be designed for a large volume flow.

A further advantageous embodiment relates to such a dampening solution circuit in which the ratio between the first dampening solution sub-stream and the second dampening solution sub-stream can be controlled and / or regulated.

Also preferred is a design of a dampening solution circuit in which the first dampening solution partial flow can be regulated on the basis of a determined difference between the main fountain solution stream and the second dampening solution sub-stream. A regulation of the second dampening solution sub-stream is preferably carried out "dampening-based", i. regardless of the first dampening solution part stream to be cleaned. The control prioritizes the operation of the dampening unit. Therefore, a cleaning device can be installed in an existing dampening circuit without affecting the dampening system control.

Furthermore, such a dampening solution circuit preferably has a design in which the dampening solution return further comprises an intermediate container and a removal device, which are permitted such that dampening solution in the intermediate container, coming from one or more dampening units, is collectable, and that the first dampening solution partial stream by means of Removal device is derivable from the intermediate container. Preferably, the dampening solution circuit and the intermediate container are designed such that adjust different concentrations of impurities in the dampening solution at different locations of the intermediate container in the dampening solution during operation of the dampening solution circuit (eg due to different flow conditions in the intermediate container and / or different density of dampening solution and impurities). In this case, the removal device in the dampening solution is preferably arranged at a point at which a higher impurity concentration is established during operation of the dampening solution circuit than at other points in the intermediate container. Different flow conditions in different areas of the Intermediate container can be generated, for example by inducing a rotating flow, with impurities depending on the density difference in relation to dampening in the center of a vortex generated or in the radial direction outside in the edge region of the vortex reach a higher concentration than in other areas of the flow. Furthermore, it is preferable to create flow conditions in the area of influence, wherein in certain areas in the intermediate container, a standstill or approximately a standstill of the dampening solution is achieved. As a result, rising and / or sinking of impurity particles or fluids in the dampening solution are made possible or promoted, so that corresponding impurities collect in certain floor areas or in certain areas of the dampening surface FO. In this case, the intermediate container preferably has a volume of between 20 l and 300 l, more preferably between 50 l and 150 l. For example, for smaller machines an intermediate container size of 50 liters may be preferred, and for roll machines having a roll width of about 2 meters, the intermediate container may have a filling volume of between 100 and 150 liters. In this case, volume size and / or flow duration are preferably dimensioned such that the average residence time of the dampening solution is between half a minute and 3 minutes, more preferably about 1 minute. Furthermore, a plurality of removal devices are preferably provided, which are arranged in the dampening solution at a plurality of locations with high concentrations of different impurities such that dampening solution substreams with different impurities are supplied to different purification devices. For example, color residues and / or oily residues in the area of the fountain solution surface can be removed, and pressure powder, which settles more on the bottom, can preferably be removed together with a dampening solution stream in the bottom area of the intermediate container. Furthermore, a pump is preferably provided in the intermediate container, which returns dampening solution from the intermediate container in the dampening solution supply, wherein preferably at least a portion of the dampening solution is traceable into the fountain solution main container. In this case, the pump can be provided at a location at which the first dampening solution partial flow after passing through the dampening solution cleaning device already back to the second Feuchtmittelteilstrom is united (eg when the second dampening solution partial stream is returned after cleaning in the intermediate tank.) Or the pump can only promote the second dampening solution part stream (eg if the second dampening solution partial stream is introduced directly into the fountain solution main tank). Preferably, the dampening solution return opens into the fountain solution main container.

Furthermore, an embodiment of the dampening solution circuit in which the cleaning branch opens into the intermediate container behind the dampening solution cleaning unit in the conveying direction is preferred.

A further advantageous embodiment relates to such a dampening solution circuit in which the cleaning branch is connected directly to the fountain solution main container, so that the first dampening solution partial stream can be introduced directly into the dampening solution main container after the dampening solution cleaning device.

Also preferred is an embodiment of the dampening solution circuit, in which the removal device is designed in such a way that dampening solution can be removed via the removal device at different fill levels in the intermediate container in the region of the dampening surface. Such a removal device can be designed so controllable that, for example, a removal opening of the removal device moves with changing level of the fountain solution in the intermediate container up or down. This can be done for example by a surface skimmer, the removal opening of the wandering dampening surface is tracked via a float. It is conceivable an electronic control of the position of such a removal opening, wherein the control is preferably carried out in response to signals from one or more level sensors. Also conceivable is the use of a belt chute, whereby the belt of the belt chute circulates over a certain height difference and so, without a position of the belt chime has to be changed, the belt can still be brought into contact with impurities that accumulate in the area of the dampening surface even if the Moisturizer level rises or falls. It is also conceivable a combination of these options with each other or with other options.

A further advantageous embodiment relates to a dampening solution circuit in which the removal device has a discharge edge, which is arranged below the fountain solution surface such that the discharge of the dampening solution takes place by means of flow of the dampening solution over the outflow edge. In this case, the outflow edge can preferably be arranged as a function of the filling level in the intermediate container at a certain distance from the dampening solution surface. A drainage edge may e.g. be the edge of a pipe or a hose, which can be moved from below to the fountain solution surface. It is preferred if the edge is designed and can be moved to the dampening surface such that it does not have any areas projecting beyond the dampening surface, since such protruding areas are easily contaminated. Furthermore, it is preferred if the outflow edge is adjustable via a float or via an above-mentioned electronic device at a preferred distance from the dampening surface. In this case, it is preferable for the outflow edge to be adjustable over a distance range at different distances to the dampening surface, so that over the length of the outflow edge in conjunction with the level reaching beyond the edge, a defined dampening agent outflow can be generated.

Preferably, such a dampening solution circuit has a design in which the intermediate container is divided by an intermediate wall into an area of influence and an outflow region, wherein the introduction of the dampening solution coming from the dampening unit or dampers takes place in the area of influence, wherein the intermediate wall has a flow opening through which a Flow between the influence area and the discharge area is made possible, and wherein the flow opening is arranged below a minimum filling level of the dampening solution in the area of influence. This allows a separation between the area of influence and the discharge area, so that the dampening solution before it flows through the flow opening, remains sufficiently long in the sphere of influence, so that impurities can rise or settle to the dampening surface. It is preferred if the statements made above with respect to the intermediate container essentially apply to the influence range, so that corresponding impurities accumulate in certain floor areas or in certain areas of the dampening surface FO. In this case, the influence range preferably has a volume of between 20 l and 300 l, more preferably between 50 l and 150 l. For example, for smaller machines, an influence range size of 50 l may be preferred, and for roller machines having a roll width of about 2 m, the influence range may have a fill volume of between 100 l and 150 l. In this case, the volume size and / or flow duration are preferably dimensioned such that the average residence time of the dampening solution is within the range of influence between half a minute and 3 minutes, more preferably about 1 minute. Furthermore, a plurality of removal devices are preferably provided in the area of influence, which are arranged in the dampening solution at several points with high concentrations of different impurities such that dampening solution substreams with different impurities are supplied to different cleaning devices. For example, color residues and / or oily residues in the area of the fountain solution surface can be removed, and pressure powder, which settles more on the bottom, can preferably be removed together with a dampening solution stream in the bottom area of the intermediate container. Furthermore, the flow opening is preferably arranged in the bottom region of the influence region, since the impurities usually have a lower density than the dampening solution and therefore rise to the surface. The volume of the influence area is preferably dimensioned such that an average time of residence of the dampening solution in the area of influence is ensured, which makes it possible to drive on lighter components such as oil and dyes. Preferred is an upwardly tapering design of the area of influence which causes upwardly rising impurities to accumulate concentrated in the tapered area.

Also preferred is such a dampening solution circuit in which the cleaning unit has a separator. A separator may, in a preferred embodiment, e.g. be provided in the form of a centrifuge.

A further advantageous embodiment relates to such a dampening solution circuit in which the cleaning unit has a cross-flow filter. In cross-flow filtration, a flow on a suspension side is generated substantially parallel to a filter medium, wherein the filter medium of the liquid is transversely permeable, while the impurities are preferably carried away largely with the flow. The advantage of the cross-flow filtration is that a deposition of impurities on the filter medium is prevented or made more difficult by the flow parallel to the filter medium. In this case, preferably permanent filter materials are used. Also conceivable is the additional or alternative use of consuming filter materials.

Further preferred is a design of a dampening solution circuit, in which the cleaning device has a filter unit with exchangeable filters. Such filters may e.g. be provided in the form of filter bags or filter mats. Conceivable are also other filter forms. The advantage of these embodiments lies in a favorable device price.

Furthermore, such a dampening solution circuit preferably has a design in which the cleaning device is constructed as a cascade system.

Another aspect of the invention relates to a printing machine with such a dampening solution circuit.

In the following, individual, particularly preferred embodiments of the invention are described by way of example. Some of the described embodiments have features that are not necessarily required to practice the present invention, but are generally considered preferred. So are also embodiments as under the doctrine of Invention, which does not have all the features of the embodiments described below. Similarly, it is conceivable to selectively combine features described with respect to different embodiments.

Brief description of the drawings

Fig. 1

eine schematische Darstellung eines Feuchtmittelkreislaufs, der hilfreich zum Verständnis der Erfindung ist,

Fig. 2

eine schematische Darstellung einer bevorzugten Ausführungsform eines erfindungsgemäßen Feuchtmittelkreislaufs,

Fig. 3

eine schematische Darstellung einer bevorzugten weiteren Ausführungsform eines erfindungsgemäßen Feuchtmittelkreislaufs,

Fig.4

eine schematische Darstellung eines bevorzugten Zwischenbehälters mit einer bevorzugten Entnahmevorrichtung im Querschnitt und

Fig. 5

eine vergrößerte Ansicht der Entnahmevorrichtung aus Fig. 4 im Bereich einer Entnahmeöffnung.

It shows:

Fig. 1

a schematic representation of a dampening solution circuit, which is helpful for understanding the invention,

Fig. 2

a schematic representation of a preferred embodiment of a dampening solution circuit according to the invention,

Fig. 3

a schematic representation of a preferred further embodiment of a dampening solution circuit according to the invention,

Figure 4

a schematic representation of a preferred intermediate container with a preferred removal device in cross section and

Fig. 5

an enlarged view of the sampling device Fig. 4 in the area of a removal opening.

Detailed description of the drawing

Fig.1 shows a schematic representation of a dampening solution circuit 1 according to the invention, which is helpful for understanding the invention.

Shown is a dampening solution main container 3, in which a certain amount of ready-dampening solution is provided, which by means of a pump not shown in more detail the dampening solution via a dampening solution supply 4 a Dampening unit 2 feeds. There are in the Fig. 1 schematically illustrated four towers, each having at least one dampening unit 2.

Excess dampening solution is collected in the dampening units 2 and discharged via various lines from the various dampening units. Subsequently, the various volume flows are combined in a dampening solution return 5 to a main fountain solution F _H. The dampening solution return 5 may have various components, such as pipes, reservoir etc.

In Fig. 1 a dampening solution circuit is shown, which is helpful for understanding the invention. Here, a first area of dampening solution recirculation 5 opens into a cleaning branch 6, so that the entire main fountain solution flow F _{H is passed} through a dampening solution cleaning device 7. In the fountain solution cleaning device 7, the dampening solution is cleaned by various, not shown devices of impurities.

Subsequently, the cleaning branch 6 opens in a second section of dampening solution recirculation 5, so that the main fountain solution flow F _H , is returned to the fountain solution main container 3.

According to the dampening solution circuit shown, no pump is provided in the flow direction between the dampening units and the dampening solution cleaning device 7, so that the dampening solution is supplied by the dampening units 2 solely on account of the gravity of the dampening solution cleaning device 7, as can also be in the embodiments of the invention. This has the advantage that the formation of an emulsion of dampening solution and color components contained and / or oily impurities is avoided.

Fig. 2 shows a schematic representation of a preferred embodiment of the dampening solution circuit 1 according to the invention.

According to this preferred embodiment, an intermediate container 8 is provided in the dampening solution recirculation 5. Preferably, the main fountain solution flow F _H coming from the dampening units 2 is fed to the intermediate container 8 solely on the basis of gravity. In the illustrated embodiment, dampening solution 8 is introduced from all the dampening units 2 shown in the intermediate container. The fountain solution collected in the intermediate container 8 passes through the intermediate container 8, and is then fed to the fountain solution main container 3.

In this case, the dampening solution recirculation 5 is designed such that the main fountain solution stream is both fed to the intermediate container 8 in its entirety and forwarded from this into the fountain solution main container 3. Further, according to this embodiment, a cleaning branch 6 is provided, which derives a first dampening solution part stream F _T1 from the fountain solution main stream F _H , passes through a dampening solution cleaning device 7 and then back into the intermediate container 8.

Here, in this preferred embodiment, the cleaning branch 6 is designed so that the first dampening solution part stream F _{T1 is} only part of the fountain solution main flow F _H , so that in the intermediate container 8, a second dampening solution partial flow F _{T2 is} formed, which without passing through the cleaning device in the fountain solution main three is returned.

Preferably, the first dampening solution partial flow F _{T1 of} the dampening solution cleaning device 7 is supplied solely on the basis of gravity. Such a device has the advantage that the dampening solution is not whisked by pumping, so that the impurities in the dampening solution cleaning device 7 are easy to separate from the dampening solution.

A removal device 9, which takes the dampening solution from the intermediate container 8, and a preferred design of the intermediate container will be described below with reference to FIGS. 4 and 5 described.

According to the preferred embodiment, the first dampening solution partial flow F _T 1 is taken both from the intermediate container and also returned to this. According to another, not shown, preferred embodiment, the first dampening solution partial flow F _{T1 is} not returned to the intermediate container 8 but directly into the fountain solution main container 3.

Furthermore, it is conceivable that in addition to the lines shown, a further line fount solution from the fountain solution main container three into the intermediate container eight passes, so that the dampening solution cleaning device 7 can be operated even when the dampening solution circuit 1 is stationary. In this way, the fountain solution cleaning device 7 can also be operated at standstill of the printing press.

Fig. 3 shows a schematic representation of a preferred further embodiment of the dampening solution cycle according to the invention.

This embodiment substantially corresponds to the embodiment which is described in FIG Fig. 2 is shown so that in order to avoid repetition, the elements already described will not be described again.

In the illustrated embodiment, the design of the dampening solution cleaning device 7 is shown in more detail. It can be seen that the cleaning device preferably has a plurality of cleaning elements. These may for example comprise a separator and / or a cross-flow filter and / or a filter unit and / or a cascade system.

The individual cleaning elements can be arranged sequentially, parallel, partially sequential and partially parallel and / or cascading.

As in Fig. 3 illustrated, the dampening solution cleaning device 7 on the input side, a pump which presses the dampening solution, for example by a filter unit. Although it is preferred according to the invention that no pump is provided between dampening unit and cleaning device. However, preferred embodiments can also be provided with a pump, in particular if the pump is designed such that dampening solution and impurities are not whisked together in such a way that an emulsion is produced. This can be achieved, for example, by particularly slow running pumps. Further, when a pump is provided, it is preferable (in addition to or as an alternative to the described pump design), to provide the pump at a location below the fountain solution level. This has the advantage that even with a turbulence no air comes into contact with the dampening solution and the impurities. It has surprisingly been found in this context that the air contact generates a particularly disadvantageous form of emulsification in turbulence, which is particularly difficult to split in the cleaning device.

Fig. 4 shows a schematic representation of a preferred intermediate container 8 with a preferred removal device 9 in cross section.

Such a preferred intermediate container 8 can be used in a dampening solution circuit 1 described above. The illustrated intermediate container has an area of influence 81 and an outflow area 82, which are each preferably trough-shaped. Furthermore, influence region 81 and / or outflow region 82 can also be executed closed. In this case, a part of the dampening solution recirculation 5 coming from the dampening unit 2 opens in the area of influence 81. The mouth of the dampening solution return, through which the main fountain solution flow F _{H is directed} into the area of influence 81, is shown schematically as a water tap-like structure above the dampening surface in the area of influence 81 However, it may be preferable to arrange the mouth below the dampening surface FO, eg in the bottom area of the influence area. Preferably, the mouth is introduced into the sphere of influence, that preferred flow conditions are created in the area of influence, which promote separation of the impurities from the dampening solution.

For example, It is preferred to create flow conditions in the area of influence, which ensure a residence time of the dampening solution and / or a minimum fluid movement in the area of influence. As a result, rising and / or sinking of impurity particles or fluids in the dampening solution are made possible or promoted, so that corresponding impurities collect in certain floor areas or in certain areas of the dampening surface FO. A similar effect can be produced by causing a rotating flow, with impurities having smaller or larger densities in the center of a generated vortex or in the radially outward direction in the edge region of the vortex reaching a higher concentration than in other regions of the influence region 81.

In the illustrated preferred embodiment, a rest basin is shown, in which a particularly preferred removal device 9 is arranged such that its removal opening is arranged just below the dampening solution level. The removal opening is with respect to Fig. 5 described below.

Furthermore, the influence range 81 at the in Fig. 4 illustrated embodiment of an outflow region 82 via an intermediate wall 83 is formed separately. As shown, the influence region 81 and outflow region 82 are preferably connected to one another in the bottom region 82 of the influence region 81 via a flow opening 84. The flow opening 84 is preferably formed in the intermediate wall 83.

In this preferred embodiment, a second dampening solution part flow F _{T2 flows} through the flow opening 84. The first dampening solution part flow F _T1 flows purified into the outflow area 82 in the illustrated preferred embodiment. It is also conceivable to direct the cleaned first dampening solution sub-stream F _T1 directly into the main fountain solution container or to transfer the first dampening solution sub-stream F _T1 into to initiate the area of influence 81, so that the entire main fountain solution flow F _{TH flows} through the flow opening 84. Furthermore, it is conceivable to carry out the intermediate container with no intermediate wall or to provide several intermediate walls in a labyrinthine manner.

Fig. 5 shows an enlarged view of the sampling device 9 from Fig. 4 in the region of the removal opening 91.

In this case, the removal device is designed so that the fountain solution of gravity following in the removal opening runs. In this case, the flow conditions are designed so that impurities with a lower density occur in a particularly high concentration in the region of the dampening surface FO and flow together with the dampening solution via the outflow edge 91 of the removal opening 91. A first dampening solution partial flow F _T1 generated in this way therefore has a particularly high contamination with impurities. This has the advantageous effect that a small dampening solution partial flow F _T1 leads to a high cleaning effect. By such a design, it is possible to make a cleaning of the entire dampening main stream superfluous, so that the dampening solution cleaning device 7 can be interpreted to a lower volume flow.

As in Fig. 5 is also apparent, the drainage edge is arranged at a distance .DELTA.H to the dampening surface FO. It is preferred if the removal device is designed such that the distance .DELTA.H can be variably set or regulated to different values, so that the size of the volume flow of the first dampening solution partial flow F _T1 can be adjusted.

Furthermore, it is preferred if the removal device 9 is adjustable in the influence region 81 over a variable range, following the level of the dampening solution, so that the removal device can be operated at different fill levels.

An adjustment and / or regulation of the removal device 9 can thereby mechanically (eg via a float) or electronically in response to level signals from one or more level sensors. For example, level sensors can record the pressure in the dampening solution and convert it into a signal or via an electrical resistance measurement. Conceivable here are any forms of sensors.

In the illustrated preferred embodiment, the removal device is tubular, so that a substantially circular removal opening 91 is provided. Conceivable are any other forms of a withdrawal edge. Such as, for example, a substantially planar, height-adjustable slide, which separates a further region in the area of influence into which the first dampening solution partial flow F _{T1 flows} in the direction of the dampening solution cleaning device 7.

LIST OF REFERENCE NUMBERS

1

Dampening solution circuit

2

dampening

3

Dampening solution main reservoir

4

Water feeding

5

Dampening solution return means

6

cleaning branch

7

Dampening solution cleaning apparatus

8th

intermediate container

81

sphere of influence

82

outflow region

83

partition

84

Flow opening

85

Ground area of the influence area

9

removal device

91

removal opening

92

outflow edge

FO

Dampening solution surface

F _H

Dampening solution main flow

F _T1

first dampening solution partial flow

F _T2

second dampening solution partial flow

AH

Distance between drainage edge and fountain solution surface

Claims (15)

1. A dampening solution circuit (1) for a printing machine, wherein the dampening solution circuit (1) comprises at least one dampening unit (2), a dampening solution main reservoir (3), a dampening solution supply means (4) and a dampening solution return means (5),
   wherein the dampening solution supply means (4) is arranged between the -dampening solution main reservoir (3) and the at least one dampening unit (2) in such a manner that the dampening solution can be fed to the at least one dampening unit (2) from the dampening solution main reservoir (3) via the dampening solution supply means (4),
   wherein the dampening solution return means (5) is arranged between the at least one dampening unit (2) and the dampening solution main reservoir (3) in such a manner that dampening solution can be returned from the at least one dampening unit (2) via the dampening solution return means (5) into the dampening solution supply means (4),
   characterized in that the dampening solution circuit is configured in such a manner that a dampening solution main flow (F_H) coming from the at least one dampening unit (2) is dividable into a first dampening solution partial flow (F_T1) and a second dampening solution partial flow (F_T2), wherein the second dampening solution partial flow (F_T2) can be created parallel in time and separated in space from the first dampening solution partial flow, and wherein a cleaning branch (6) with a dampening solution cleaning apparatus (7) is provided in the region of the dampening solution return means (5), which cleaning branch (6) is configured in such a manner that during the operation of the dampening solution circuit (1) the first dampening solution partial flow (F_T1) can be passed from the dampening solution main flow (F_H) through the dampening solution cleaning apparatus (7), and
   wherein the cleaning branch (6) is connected with the dampening solution circuit (1) in such a manner that the dampening solution cleaned in the dampening solution cleaning apparatus (7) can be returned into the dampening solution supply means (4), and
   wherein the dampening solution circuit is configured in such a manner that the second dampening solution partial flow (F_T2) can be returned into the dampening solution main reservoir (3) without passing the cleaning apparatus.
2. The dampening solution circuit (1) according to claim 1, wherein the dampening solution return means (5) is configured in such a manner that no dampening solution pump is provided between the dampening unit (2) and the dampening solution cleaning apparatus (7).
3. The dampening solution circuit (1) according to any one of the preceding claims, which is configured in such a manner that the second dampening solution partial flow does not pass a cleaning apparatus on its path into the dampening solution supply means (4).
4. The dampening solution circuit (1) according to any one of the preceding claims, which is configured in such a manner that the ratio between the first dampening solution partial flow (F_T1) and the second dampening solution partial flow (F_T2) is controllable respectively open-loop and/or closed-loop controllable.
5. The dampening solution circuit (1) according to claim 4, which is configured in such a manner that the first dampening solution partial flow (F_T1) is controllable based on a determined difference between the dampening solution main flow (F_H) and the second dampening solution partial flow (F_T2).
6. The dampening solution circuit (1) according to any one of the preceding claims, wherein the dampening solution return means (5) further includes an intermediate reservoir (8) and an extraction apparatus (9), which is configured in such a manner that dampening solution is collectable in the intermediate reservoir (8), coming from one or more dampening units (2), and that the first dampening solution partial flow (F_T1) can be drained from the intermediate reservoir (8) by means of the extraction apparatus (9).
7. The dampening solution circuit (1) according to claim 6, wherein the cleaning branch (6) opens out into the intermediate reservoir (8) downstream from the dampening solution cleaning unit as seen in the feeding direction.
8. The dampening solution circuit (1) according to any one of the preceding claims, wherein the cleaning branch (6) is directly connected to the dampening solution main reservoir (3) so that the first dampening solution partial flow (F_T1) can be fed directly into the dampening solution main reservoir (3) downstream from the dampening solution cleaning apparatus (7).
9. The dampening solution circuit (1) according to claims 6 to 8, as far as claim 8 refers back to claims 6 and 7, wherein the extraction apparatus (9) is configured in such a manner that dampening solution can be withdrawn by means of the extraction apparatus (9) at various filling levels in the intermediate reservoir (8) in the region of the dampening solution surface (FO).
10. The dampening solution circuit (1) according to any one of claims 6 to 9, wherein the extraction apparatus (9) has an outflow edge (92), which is arranged below the dampening solution surface (FO) in such a manner that draining of the dampening solution is carried out by flowing out of the dampening solution across the outflow edge (92).
11. The dampening solution circuit (1) according to any one of claims 6 to 10, wherein the intermediate reservoir (8) is separated into an inflow region (81) and an outflow region (82) by means of a separating wall (83), wherein introduction of the dampening solution coming from the one or more dampening units (2) is in the inflow region (81), wherein the separating wall (83) has a flow-through opening (84) through which a fluid flow between the inflow region (81) and the outflow region (82) is enabled, wherein the flow-through opening (84) is arranged below a minimal filling level of the dampening solution in the inflow region (81).
12. The dampening solution circuit (1) according to any one of the preceding claims, wherein the cleaning unit includes a separator.
13. The dampening solution circuit (1) according to any one of the preceding claims, wherein the cleaning unit comprises a cross-flow filter.
14. The dampening solution circuit (1) according to any one of the preceding claims, wherein the cleaning apparatus comprises a filter unit with replaceable filters.
15. The dampening solution circuit (1) according to any one of the preceding claims, wherein the cleaning apparatus is configured as a cascade system.

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