DE10213959A1 - Moisturizing water circuit sector for offset printing press has cleaning device including cleaning tank, extraction device and filter housing - Google Patents

Abstract

The moisturizing water circuit sector includes a cleaning device which has a cleaning tank (10), an extraction device (12) to remove dirt from the water (14) in the tank, leaving the water behind, and a filter casing (16), at least one wall of which is in the form of a filter mesh (18), fitted in the tank below a preset water level (20).

Description

The invention relates to a dampening water circuit section of a Fountain solution circuit of a fountain solution offset printing machine according to the The preamble of claim 1, comprising a cleaning device for cleaning of the recirculating fountain solution.

A fountain solution circuit section of this type is known from EP 0 602 312 B1. It shows a fountain solution reservoir, of which a flow line is included a pump leads to a fountain of a printing unit and which one Return line from the fountain solution in the reservoir. In the Return line is a replaceable filter either immediately after the fountain of the printing unit and / or at the outlet of the return line in the storage container. The filter must be replaced from time to time with a new filter be replaced before it gets dirty from the fountain solution has a high flow resistance. Contamination in the fountain solution are especially paper dust and ink particles from the printing unit. The printing unit takes up part of the fountain solution from the fountain tank, the remaining portion of the dampening water flows through the return line into the Storage container back. The one used by the printing unit is in the reservoir Fountain solution portion added. Furthermore, the fountain solution is in the reservoir conditioned, for example by dosing fresh water, alcohol or Alcohol substitute or one or more additives through which the Print quality is affected. The additives can be used instead or in addition Contain anti-corrosion agents. The additives should be the wetting, the color Water balance, the resistance of the dampening water against Impurities and beneficial to bacteria. They also serve to keep the pH of the fountain solution at an optimal value. Therefor Acids, for example, are suitable. The fountain solution can through the Flow line and / or through the return line through pumps and / or through Gravity. The fountain solution is removed from the by a roller Transfer the dampening water pan to the rollers of a dampening system, which Fountain water on a plate cylinder and / or on other cylinders of the Transfers printing unit. The dampening water on the plate cylinder serves to to form ink-repellent areas corresponding to a desired printed image. In so-called spray dampening systems, as known from EP 0 325 381 A2 the flow line does not open into a fountain solution but into one Spray bar, which the fountain solution through a variety of nozzle openings a roller of the printing unit sprays, for example on a dampening roller. In this case, too, the dampening water is the spray bar with excess amount fed and a non-sprayed portion of the fountain solution into the reservoir returned. Filters can also be used to clean the fountain solution here become.

Replacing a dirty filter with a clean filter requires Personnel and working hours, and the dirty filters must be disposed of as special waste become. Another option would be to wash them. This would also be a costly effort and also here the wash water should be considered Hazardous waste can be disposed of as there are chemicals from paper dust, dampening water and Contains printing inks.

The invention is intended to solve the problem of cleaning the Dampening water required time and the environmental impact from it to reduce.

This object is achieved according to the invention by the features of claim 1 solved. The object is accordingly achieved in that the cleaning device a cleaning tank, a conveyor for conveying out Contamination from the dampening water in the cleaning tank, leaving it behind of the dampening water and has a filter housing which is at least one as Filter screen formed housing wall, which is in the cleaning tank below a predetermined level of dampening water over an area of the tank bottom is arranged, over which the conveying device extends in order to out of this Take dirt from the fountain solution with you outside of the Filter housing a fountain solution feeds into the cleaning tank, and that a Fountain water outlet from the interior of the filter housing is provided so that a fountain solution flow path from the fountain solution inlet to the cleaning tank and from this through the filter screen into the filter housing Fountain water outlet is formed.

The filter, the conveyor and the collecting container can in the same way be designed, such as this from the utility model DE 200 20 244 U1, DE 201 14 853 U1, DE 201 14 854 U1, DE 298 22 220 U1 is known. The filters used therein or sieves used as filters can also be used in the new invention can be used. Fabrics, perforated sieves and in particular so-called slotted screens, whose screen opening widths are smaller than that Damp water to be screened out are color particles, dirt particles and fiber dust. The mesh size or gap width is, for example, only 30 μm or less. This type of filtering devices have the advantage that the filters are automatic be cleaned or soaked by the fountain solution that none Need cleaning or only in very long time intervals. Another advantage is that they are also with high throughput (Dampening water volume / unit of time) of, for example, 200 liters / minute and more are operable. The devices resulting from the aforementioned Utility models are known are not for cleaning fountain solution from Offset printing machines designed, but for separating and discharging Metal shavings from working fluids (lubricating oil, cooling oil and the corresponding ones Oil substitutes) from cutting machines. From the inventors of the Present new invention was surprisingly recognized that this for a completely foreign subject designed devices also for the cleaning of Fountain water can be formed, although the pollution in Fountain water a much smaller particle size and much smaller have a specific weight as metal chips.

Through the conveyor designed as a cleaning device for Dirt is removed from the fountain solution in the cleaning tank not only are dirt removed, but the conveyor is open the fountain solution also has a stirring effect, through which in the fountain solution Currents are created that wash contaminants away from the filter. Furthermore, in Cleaning tank also be arranged an agitator through which such Flow or swirling of the fountain solution is generated. In addition to a good cleaning of the filter, a filter cleaning device can also be provided, for example a brush device, which the filter on its upstream side (Outside) brushes, either continuously or at intervals.

Further features of the invention are contained in the subclaims.

The invention is described below with reference to the drawings preferred embodiments described as examples. In the drawings demonstrate

Fig. 1 is a schematic side view of a dampening water circulation of a fountain solution offset printing machine with a section according to the invention,

Fig. 2 is an enlarged a detail "II" of Fig. 1,

Fig. 3 is a cross-section in the plane III-III of Fig. 1,

Fig. 4 schematically shows a side view of another embodiment of a dampening water circulation with a section according to the invention,

Fig. 5 shows schematically a side view of another embodiment of a dampening water circulation with a section according to the invention,

Fig. 6 shows a cross section along the plane VI-VI of Fig. 5,

Fig. 7 schematically shows a side view of yet another embodiment of a fountain solution circuit with a section according to the invention.

2 Fig. 1 schematically shows a fountain solution circulation section of a dampening water circulation system a fountain solution offset printing machine 4, from which for example, two printing units 6 and 8 are shown.

A cleaning means for cleaning the fountain solution recirculating includes a cleaning tank 10, a conveyor 12 for feeding out contaminants from the dampening water 14 in the cleaning tank 10 while leaving the dampening water 14 and a filter housing sixteenth The filter housing 16 has at least one housing wall 18 designed as a filter screen, which is arranged in the collecting container 10 below a predetermined dampening water level 20 over an area of the tank bottom 22 over which the conveying device 12 extends in order to take dirt from the dampening water from this area.

Outside the filter housing 16 , a dampening water inlet 24 opens into the cleaning tank 10 . A fountain solution outlet 26 leads out of the interior of the filter housing 16 , so that a fountain solution flow path is formed from the fountain solution inlet 24 into the cleaning tank 10 and from there through the filter screen 18 into the filter housing 16 to the fountain solution outlet 26 .

The conveyor device 12 is designed as a continuous, endless scraper conveyor which has a lower conveyor run 12-1 and an upper conveyor run 12-2 . The scraper conveyor 12 is with scraper elements 28 , for. B. strips, rails, angle rails and / or brushes that scratch the bottom 22 of the cleaning tank 10 when the lower conveyor strand 12-1 moves over the container bottom 22 . The conveyor 12 is arranged such that the lower conveying slidably disposed 12-1 with its scraping elements 28 through the container bottom 22 and then via an up on the dampening water level 20 rising wall portion 30 of the cleaning tank 10 so as rising on the floor 22 and on the Wall part 30 to remove deposited dirt from the fountain solution and from the cleaning tank 10 . The lower conveyor strand 12-1 moves upwards on the rising wall part 30 in accordance with an arrow 32 , while the upper conveyor strand 12-2 located above it moves downwards in accordance with an arrow 34 .

The rising wall part 30 is preferably not vertical, which would also be a possible embodiment, but rather oblique and preferably has an angle of inclination between approximately 30 ° and 80 ° to the horizontal. Soiling, which was conveyed upwards from the lower conveyor strand 12-1 , can be collected or discharged at the upper edge of the wall part without dampening water and thus in a relatively dry state, e.g. B. fall outwards, for example in a container or on a conveyor belt.

The lower conveyor strand 12-1 preferably extends beyond the upper end of the rising wall part 30 and laterally outwards beyond this upper end, so that there is greater certainty that the conveyed contaminants from the upper wall part end 31-1 outside the cleaning tank 10 fall off the wall part 30 .

Preferably, however, not only the floor 22 is cleaned by the conveyor device 12 designed as a cleaning device, but also a cleaning device for cleaning the outside (upstream side) of the filter screen 18 in the cleaning tank 10 is provided. This filter cleaning device can be designed in various ways. A particularly structurally simple and effective embodiment consists in that brushes 3 E3 are provided for mechanically brushing the outside of the filter screen 18 . The brushes 36 can be carried by a brush device or, as shown in FIG. 1, can be attached to the scraper conveyor 12 so that they rotate with it, the filter 18 being arranged in the path of movement of the brushes 36 so that they are brushed off by them. The brushes 36 can simultaneously be the scraper elements of the scraper conveyor 12 or can be provided in addition to the scraper elements 28 . If the brushes 36 are provided in addition to relatively stiff scraper bars or scraper elements 28 , they preferably protrude beyond them transversely to the direction of conveyor movement 32 , 34 . As a result, only the brushes 36 scrape on the outside of the filter screen 18 , but not the other scraping elements 28 .

In the embodiment of FIG. 1, only the bottom wall of the filter housing 16 is designed as a filter screen 18 , whereas the housing side walls 38 are impermeable to the dampening water.

In the cleaning tank 10, a stirrer 42 may be disposed, with which the dampening water 14, a water flow is produced if this is advantageous for the cleaning of the dampening water 14 to achieve a better efficiency.

As shown in FIGS. 2 and 3, the scraper conveyor for example, has left an endless chain 44 and right endless chains 46 which are guided in guides 48, 49, 50, 51 in a feeder box having side walls 52 and 53. The guide elements can be sliding bodies or rollers. The chains 44 and 46 are driven by chain sprockets 56 , which are preferably arranged outside the fountain solution.

A reservoir 58 for the dampening water forms the starting point, from which a feed branch 60 leads to the printing units 6 and 8 , and into which a return branch 62 opens, which is connected to the dampening water outlet 26 of the filter housing 16 . The flow and / or the return can convey the fountain solution by gravity or can be provided with a pump 64 or 66 for delivery. The dampening water has the flow direction indicated by arrows 64 in the flow branch 60 and the flow direction indicated by arrows 66 in the return.

The flow branch 60 has a flow inlet 68 in the reservoir 58 . The return branch 62 has an outlet 70 opening into the reservoir 58 . Connections 72 and 74 are also provided, through which components of the dampening water, for example fresh water, alcohol or alcohol substitute, can be metered into the reservoir 58 , and additives, such as an acid or a corrosion inhibitor, for influencing the printing process and the printing quality.

The feed branch 60 has an outlet 78 and 79 , which opens into a fountain solution 80 or 82 of the printing unit 6 or 8 . The dampening water pan 80 and 82 are each provided with an overflow 84 and 86 , respectively, via which dampening water not taken up by dampening unit rollers 87 and 88 , respectively, can flow into an inlet 89 or 90 of the return branch 66 by gravity (or by a pump). Instead of a dampening water trough 80 or 82 , dampening water can be sprayed onto the dampening unit rollers 87 or 88 by a spray bar according to another embodiment, not shown.

The filter sieve 18 of the filter housing 16 is preferably a so-called slotted sieve with narrow gaps or slits with a very small gap width, which is smaller than the contaminants to be retained from the dampening water by this filter sieve, such as paper dust, paint particles and other contaminations of the dampening water.

In the embodiment of FIG. 4, both the bottom wall 18 and a top wall 19 of the filter housing 116 (instead of 16 of FIG. 1) are each designed as a filter screen in the manner mentioned in order to allow dampening water to flow into the interior of the filter housing 116 from the cleaning tank 10 to let and filter out dirt from the fountain solution. All side walls 38 of the filter housing 116 are water-impermeable to the fountain solution. The brushes 36 each protrude inward from the lower conveyor run 12-1 and from the upper conveyor run 12-2 into the scraper conveyor, the lower conveyor run 12-1 brushing with the brushes 36 via the lower filter screen 18 and the upper conveyor run 12-2 the brushes 36 is arranged brushing over the upper filter screen 19 . As a result, the dampening water throughput through the filter housing 116 of FIG. 4 can be approximately doubled relative to the filter housing 16 of FIG. 1. In addition, the embodiment of FIG. 4 corresponds to the embodiment of FIGS. 1 to 3.

In the embodiment of FIG. 5, the peripheral wall 238 (instead of 38 of FIG. 1) of the filter housing 216 (instead of 16 of FIG. 1) is designed as a filter screen in the manner mentioned. The bottom wall 218 (instead of 18 from FIG. 1) and a top wall 219 (instead of 19 from FIG. 1) are impermeable to water in the cleaning tank 10 . The filter screen 238 , which forms the peripheral wall of the filter housing 216 , extends around a theoretical vertical center line 92 . It is preferably a slotted screen filter having a plurality of gaps or slots 94 that extend circumferentially or preferably vertically, as shown in FIGS . 5 and 6. The top wall 219 can be permeable to water or can be omitted if the upper end of the filter housing protrudes from the fountain solution.

The filter 238 is brushed off by cleaning elements 236 , for example brushes, on the outside of the housing and is thereby cleaned. Brushes 236 , e.g. B. a brush ring is moved vertically up and down by a brush actuator 96 . The brush actuation device contains, for example, a brush carrier ring 97 with an internal thread, through which threaded spindles 98 extend, which are rotatable by a motor 99 .

The horizontal cross-sectional shape of the filter housing 216 of FIG. 5 can be circular or have another shape corresponding to FIG. 6. The filter housing 216 is arranged in a stationary manner and cannot be rotated.

In the embodiment of Fig. 7, the filter housing 316 (instead of 16 of Fig. 1 or 216 of Fig. 5) has a circular cylindrical shape concentric to the vertical center line when viewed in horizontal section.

The filter housing 316 has a cylindrical peripheral wall 338 , which is designed as a filter screen or screen, preferably as a slotted screen filter. It extends between a watertight bottom wall 318 and a watertight top wall 319 . The filter housing 316 is rotatably suspended on a motor 100 , through which a suction pipe with the dampening water outlet 26 extends. The upstream side and thus the outside of the rotating filter 338 brushes past stationary brushes 336 and is thereby cleaned by them. The conveyor device 12 designed as a scraper conveyor is designed in the same way as described with reference to FIG. 1, but without brushes. However, it can also be provided with brushes 12 if the bottom wall 318 of the filter housing 316 is also designed as a filter screen and is then to be cleaned by these brushes.

Unless details have been described for FIGS. 4 to 7, they are identical to details of FIGS. 1 to 3.

In all embodiments, the dampening water level 20 in the cleaning tank 10 is monitored by a sensor device 17 and kept at a predetermined value or within a predetermined level range with control elements (not shown) or prevented by a safety shutdown device from rising above a predetermined maximum value.

Any type that has a suitable filter effect is suitable as a filter sieve, a long one Has a lifespan and does not become clogged over a long period of use.

Claims (13)

1. fountain solution circuit section of a fountain solution circuit of a fountain solution offset printing machine, comprising a cleaning device for cleaning the recirculating fountain solution, characterized in that the cleaning device comprises a cleaning tank ( 10 ), a conveying device ( 12 ) for conveying contaminants out of the dampening water ( 14 ) in the cleaning tank ( 10 ) while leaving the dampening water ( 14 ) and a filter housing ( 16 ; 116 ; 216 ; 316 ), which has at least one housing wall designed as a filter screen ( 18 ; 18 , 19 ; 238 ; 338 ), which in the cleaning tank ( 10 ) below a predetermined dampening water level ( 20 ) is arranged over an area of the tank bottom ( 22 ) over which the conveying device ( 12 ) extends in order to take contaminations from the dampening water out of this area, outside the filter housing ( 16 ; 116 ; 216 ; 316 ) Fountain water inlet ( 24 ) in the cleaning tank opens, and that a dampening water outlet ( 26 ) from the interior of the filter housing ( 16 ; 116 ; 216 ; 316 ) is provided so that a fountain solution flow path is formed from the fountain solution inlet ( 24 ) into the cleaning tank ( 10 ) and from there through the filter screen ( 18 ; 18 , 19 ; 238 ; 338 ) into the filter housing to the fountain solution outlet ( 26 ). 2. dampening water circuit section according to claim 1, characterized in that the conveying device ( 12 ) has a circumferential, endless scraper conveyor which has a lower conveying strand ( 12-1 ) and an upper conveying strand ( 12-2 ) with over the bottom ( 22 ) of the cleaning tank (10) scratching scraper elements (28, 36), in that the lower conveying with its scraping elements (28, 36) on the container bottom (22) and thereafter a rising up over the dampening water level (20) wall portion (30) of the cleaning tank (10 ) is slidably arranged to transport dirt deposited on the floor ( 22 ) upwards out of the fountain solution. 3. dampening water circuit section according to claim 2, characterized in that the rising wall part ( 30 ) rises at an angle to the horizontal between 30 ° and 80 °. 4. dampening water circuit section according to claim 2 or 3, characterized in that the lower conveyor strand ( 12-1 ) extends over the upper end of the rising wall part ( 30 ) and laterally outwards over this upper end, so that conveyed dirt from the upper End of the wall can fall outside the cleaning tank ( 10 ). 5. dampening water circuit section according to at least one of the preceding claims, characterized in that a filter cleaning device ( 36 ; 36 ; 236 ; 336 ) for automatically cleaning the outside of the filter screen ( 238 ; 338 ) in the dampening water in the cleaning tank ( 10 ) is provided. 6. fountain solution circuit section according to claim 5, characterized in that the filter cleaning device brushes ( 36 ; 236 ; 336 ) for brushing the outside of the filter screen ( 18 ; 18 , 19 ; 238 ; 338 ). 7. dampening water circuit section according to claim 6, characterized in that the brushes ( 36 ) on the scraper conveyor ( 12 ) are fixed so that they rotate with it, and that the filter screen ( 18 ; 18 , 19 ) in the path of movement of the brushes ( 36 ) is arranged so that it is brushed off by these. 8. dampening water circuit section according to at least one of the preceding claims, characterized in that a bottom wall of the filter housing ( 16 ) is designed as a filter screen ( 18 ) and that the housing side walls ( 38 ) for the dampening water in the cleaning tank ( 10 ) are impermeable to water. 9. dampening water circuit section according to at least one of claims 2 to 7, characterized in that a bottom wall ( 18 ) and a top wall ( 19 ) of the filter housing ( 116 ) are each formed as a filter screen that the peripheral wall ( 38 ) of the filter housing ( 116 ) for the dampening water in the cleaning tank is made impermeable to water, that the scraper conveyor is provided with brushes ( 36 ) which rotate with it, that the lower conveyor strand ( 12-1 ) with the breasts ( 36 ) brushes over the lower filter screen ( 18 ) and the upper one The conveyor strand ( 12-2 ) with the brushes ( 36 ) is arranged to brush over the upper filter screen ( 19 ). 10. fountain solution circuit section according to at least one of the preceding claims, characterized in that a peripheral wall of the filter housing ( 216 ; 316 ) is designed as a filter screen ( 238 ; 338 ) which extends around a theoretical vertical center line of the filter housing. 11. fountain solution circuit section according to at least one of the preceding claims, characterized in that a cylindrical peripheral wall of the filter housing ( 216 ; 316 ) is formed by the filter screen ( 238 ; 338 ). 12. dampening water circuit section according to at least one of the preceding claims, characterized in that the at least one filter screen ( 18 ; 18 , 19 ; 238 ; 338 ) is a slotted screen filter. 13. dampening water circuit section according to at least one of the preceding claims, characterized in that a reservoir ( 58 ) for the dampening water ( 14 ) is provided, in which a return line ( 62 ) opens, which to the dampening water outlet ( 26 ) of the filter housing ( 16 ; 116 ; 216 ; 316 ) is connected that from the reservoir ( 58 ) a feed line ( 60 ) is led out for the supply of fountain solution to the printing press, and that connections ( 72 , 74 ) are provided through which the reservoir ( 58 ) components of the Damp water can be supplied in doses.