Under 35 USC 371, this application is the national stage of PCT/EP2013/000494, filed on Feb. 21, 2013, which claims the benefit of the Mar. 14, 2012 priority date of German application 10 2012 004 972.2, the content of which is incorporated herein by reference.
The invention relates to a dampening unit, i.e. to a device for applying an application liquid to a treatment surface, and to a container handling machine that includes such a dampening unit.
Dampening units for applying treatment and/or application liquids to treatment surfaces in order to produce extensive, uniform, and generally very thin coatings from the respective application liquid are. Such dampening units are used, for example, in printing devices or printing machines for offset printing. In such machines, dampening unit is assigned to each of the printing cylinders to produce a color set of a multicolor print.
In one known printing device of this type, the dampening unit has a horizontally arranged brush that can be driven to rotate. The brush is provided with the application liquid and bears against an outer surface of the printing cylinder to transfer the liquid as the brush rotates about its brush axis.
Also known is a printing device comprising a plate cylinder or printing cylinder on which a multicolor printed image is produced via a plurality of color application rollers. Provided upstream of the color application rollers, in relation to the direction of rotation of the printing cylinder, is a horizontally arranged dampening unit for applying an application liquid to the printing cylinder. The dampening unit comprises a plurality of rollers that are driven to rotate. One of these rollers is an application roller that bears against the printing roller. A brush or brush roller that is driven to rotate applies the application liquid by spraying a layer on a further roller, which then transfers the application liquid to the application roller.
The object of the invention is to provide a dampening unit by means of which a clean application even of small quantities of an application liquid to a treatment surface is possible in an inexpensive manner.
The dampening unit according to the invention is particularly suitable for applying thin, extensive, and very uniform coatings of treatment and/or application liquids, in particular for applying viscous or highly viscous treatment and/or application liquids, for example treatment and/or application liquids having a viscosity greater than 300 mPas, in small quantities. In an apparatus according to the invention, the application liquid is applied to the treatment surface by spraying in a contactless manner, without any contact between the treatment surface and the dampening unit, through an ejection window of a brush housing surrounding the brush or brush roller. The actual, i.e. effective, size of the ejection window determines the spray width and spray height with which the application liquid is applied. By suitably adjusting the effective size of the ejection window, the spray width and/or spray height can be adjusted.
One fundamental advantage of the dampening unit according to the invention lies in the fact that no pressure medium, such as compressed air, is needed, and therefore no generator for generating this pressure medium is required to apply or spray the application liquid. The dampening unit according to the invention is further characterized by a low degree of wear on its components.
In one preferred embodiment of the invention, the treatment surface is an outer surface of a container on which a coating is to be produced by the application liquid. Examples of coatings include a wet coating or a base layer or separating layer for an imprint forming the container label in connection with a direct print.
In principle, however, the dampening unit according to the invention is also suitable for other uses. For example, the dampening unit finds use in applying treatment or application liquids to surfaces of products to be printed, and to printing and/or plate cylinders of printing machines or printing units. When made portable design with an adapted supply system, the dampening unit can be used in a a system for example for applying wall paint or paints and lacquers or plastering agents. In a hygiene-optimized design, the dampening unit can also be uses as a spray apparatus for spraying, for example glazes or granular decorating agents, in a factory producing foodstuffs. It also possible to use the dampening unit in a system for spraying cleaning solutions, soaps, or the like for cleaning, for example, motor vehicles or airplanes. Another application of the inventive apparatus lies in its use as a a lubricant or coolant spraying device, for example (but not exclusively) for rolling mill applications.
In one aspect, the invention features an apparatus that includes a dampening unit that sprays viscous application liquid onto a treatment surface. Such a dampening unit includes a rotating brush driven to rotate around the axis, a liquid applicator that supplies the liquid to the brush, and a brush chamber to accommodate the brush. The brush chamber includes a wall that surrounds the brush. The wall defines an ejection window for discharging viscous application liquid that is either sprayed or spun away from the brush.
In another aspect, the invention features an apparatus having a dampening unit that sprays viscous application liquid onto a treatment surface. The dampening unit comprises a brush, a liquid applicator, and a brush chamber. The brush is driven to rotate around a dampening unit axis. The liquid applicator supplies the viscous application liquid to the brush. The brush chamber, which accommodates the brush, has a wall that surrounds the brush and that defines an ejection window for discharging viscous application liquid that is either sprayed or spun away from the brush.
In some embodiments, the brush has a brush body with a liquid path formed therein. This liquid path distributes the viscous application liquid on a circumference of the brush body. Among these embodiments are those in which the liquid path is formed at least partially by a distributor channel and by individual channels that are open on the circumference of the brush body and that open into a distributor channel.
In another embodiment, the invention includes means for applying the liquid to the brush from outside. Among these embodiments are those in which external nozzles deliver said viscous application liquid to a rubbing and wetting place for said brush.
Additional embodiments include either a stripping or striking element that cooperates with bristles of the brush and a stripping or striking edge formed by the element. Among these are embodiments in which the element is adjustable between first and second positions that can be changed relative to a brush axis. Among these are embodiments in which the element is adjustable by linear translation, and embodiments in which the element is adjustable by pivoting.
Some embodiments include a collecting beaker for collecting the viscous application liquid from at least one of the brush and the brush chamber. Among these are embodiments in which the collecting beaker is movable along an axis of the brush and relative to the brush. In these embodiments, the collecting beaker is movable relative to the brush chamber between a first position and a second position. In the first position, the collecting beaker is at a distance from the brush and the brush chamber, while in the second position, the brush is accommodated in the collecting beaker or substantially within the collecting beaker. Some of these embodiments also include a pump for conveying the viscous application liquid out of the collecting beaker, and, in at least some cases, a filling level sensor for controlling the pump.
Additional embodiments have a heater for heating the viscous application liquid that is supplied to the brush.
Yet other embodiments have either guide lugs or flaps for shaping the emission area. The guide lugs and flaps in these embodiments are provided on the ejection window.
In some embodiments, the ejection window has either an edge or a frame that comprises a coating to prevent adhesion or caking of the viscous application liquid.
Also included are embodiments that have means for shaping the emission area, with the means for shaping the emission area including a coating to prevent adhesion or caking of the viscous application liquid.
Additional embodiments include those in which the ejection window has an edge. In these embodiments, the edge is either a single-use frame or a disposable frame.
In another aspect, the invention features a container-handling machine comprising a rotating transport element and a plurality of container-handling stations disposed thereon. Each container-handling station is associated with any one of the dampening unit recited above. Among these embodiments are those that have a central fluid tank and a distribution system for conveying fluid from the central fluid tank to each of the dampening units.
As used herein, “containers” includes cans, bottles, tubes or pouches, in each case made from metal, paper/pulp, glass and/or plastic, as well as other packaging means that are suitable for being filled with products, for example with liquid or viscous products.
As used herein, “substantially” or “approximately” means deviations of ±10%, and preferably ±5%, from the exact value in each case, and/or deviations that do not affect the relevant function.
Further developments, advantages and possible uses of the invention will become apparent from the following description of examples of embodiments and from the figures. All the features described and/or shown in the figures, or in any combination, form in principle the subject matter of the invention, regardless of the way in which they are combined or refer back to one another in the claims. The content of the claims also forms part of the description.
The invention will be explained in more detail below with reference an exemplary embodiment and to the figures, in which:
Referring to
In the illustrated embodiment, the dampening unit 1 comprises a brush roller or brush 3 that is mounted such as to be able to be driven to rotate (arrow B) about a vertical axis FA thereof by an electric drive motor 4 via a belt drive 5 and via which, in the manner described in more detail below, the application liquid is applied to the treatment surface 2 by being spun off or sprayed. The dampening unit 1 is particularly suitable for spraying or applying application liquids having viscosities greater than 300 mPas.
In detail, the brush 3 includes a roller-like brush body 6 having a circular-cylindrical circumferential surface and a bristle region 7 consisting of a large number of bristles projecting radially away from the circumferential surface of the brush body 6. The bristles form tufts 8, each of which has a large number of bristles.
At the upper end, as shown in the figures, the brush body 6 is connected to a shaft 9 that is arranged coaxial with the axis of the brush body 6 and also coaxial with the axis FA, and by which the brush 3 is mounted in an upper, plate-like bearing element 10 by ball bearings 11, in a manner such as to be able to rotate about the axis FA. The axis is the vertical axis during operation of the dampening unit 1. Also attached to the bearing element 10 is the motor 4, the shaft of which, as well as the shaft 9, protrude beyond the top of the bearing element 10 facing away from the brush 3 and are connected to one another there via the belt drive 5. In a manner that is not shown, but is likewise suitable, the brush 3 can be rotated directly via a servomotor or a comparable drive.
In the illustrated variant, the shaft 9 is designed as a hollow shaft with a fluid channel 9.1 that continues into a fluid or distributor channel 6.1 in the brush body 6. The two channels 9.1 and 6.1 are arranged coaxial with the axis FA. Individual channels 12 open into the distributor channel 6.1. The channels 12 are each oriented with their longitudinal extent radial or substantially radial to the axis FA and may also serve to hold the tufts 8 so that each individual channel 12 opens within a tuft of bristles 8 on the circumference of the brush body 6. When using media of higher viscosity, discharge channels may also be provided between the bristles. Via a rotary connection formed in the bearing element 10, the channel 9.1 is connected to an external connection 13 for supplying the liquid medium. In this case, a rotary passage or rotary connection is attached as an additional element to the shaft 9 or the shaft 9 is connected thereto.
One variant, which is technically simpler, provides for introducing the application fluid through the bearing element 10 via bores that are designed as nozzles. As a result, the application fluid is sprayed onto the brush 3 from above.
One special feature of the dampening unit 1 lies in the fact that the rotating brush 3 is accommodated in a brush housing 14 that, in the illustrated embodiment is a cylinder having a circular cross-section and that is formed substantially by a wall 15 and that is arranged with its axis coaxial to the axis FA. In the region of its upper edge, the wall 15 is attached to the underside of the bearing element 10 facing towards the brush 3. As also shown in particular in
The wall 15 is provided with an ejection window 16. In the illustrated embodiment, the ejection window 16 is an elongate opening oriented with its longitudinal extent in the direction of the axis FA and that extends almost from the upper to the lower edge of the sleeve-like brush chamber 14. Provided at the ejection window 16 is a holder 17 for a stripping or striking element 18. In the embodiment shown in
In the embodiment shown in
The dampening unit 1 further comprises a collecting beaker 19 that has a closed circumferential wall 20. In the illustrated embodiment, the wall 20 defines a cylinder having a circular cross-section and a base. With its circumferential wall 20, the collecting beaker 19 is likewise arranged concentric to the axis FA. The collecting beaker 19 is movable in the direction of the axis FA (double-headed arrow C), namely between a lower end position, shown in
For the adjusting or stroke movement, shown by the double-headed arrow C, the collecting beaker 19 is attached to a carriage 22 that, in turn, is guided in a carriage guide on a mounting frame 23 of the dampening unit 1 such as to be displaceable in the direction of the axis FA. A control drive 24 adjusts the carriage 2 and the collecting beaker 19. The control drive 24 is designed as a linear drive and is likewise provided on the mounting frame 23. The bearing element 10 is also attached to the mounting frame 23.
Provided on the collecting beaker 19, which serves for collecting the application liquid flowing off or dripping from the brush 3, is a pump 25 that is controlled by a filling level sensor, shown in
In parallel with this, a suitable cleaning agent, in particular an alcoholic or water-based fluid, is circulated. In this case, the brush can also be driven in CIP mode.
Furthermore, the cleaned and non-loaded brush 3 can be loaded in a first step, while the collecting beaker 19 is still raised and the dampening unit 1 is still closed, in order to immediately bring about the desired fluid discharge performance.
In a manner not shown in
The mode of operation of the dampening unit 1 can be described as follows:
In order to apply the application liquid to the treatment surface 2, in the illustrated variant the application liquid is supplied, while the brush 3 rotates, via the external connection 13 and via the channel 9.1 of the shaft 9 to the distributor channel 6.1 and then passes, in a manner distributed between the radial individual channels 12, to the tufts of bristles 8 so that the application liquid reaching the tufts of bristles is applied or sprayed in a finely distributed or atomized manner through the ejection window 16 onto the treatment surface 2 as a result of the centrifugal force or by spinning, and also due to the spring-back of the bristles of the bristle region 7 moving past the stripping element 18. In the process, the treatment surface 2 is moved past the ejection window 16 in an axial direction tangential or substantially tangential to the direction of rotation of the brush 3. Meanwhile, the collecting beaker 19 is positioned such that the brush chamber 14 extends at least with its lower, open end into the collecting beaker 19. The ejection or emission area 26, in which the atomized application liquid is applied, is defined by the size of the ejection window 16. By adjusting the collecting beaker 19 so that it covers the ejection window to a greater or lesser extent with its wall 20, the emission area 26 can be adjusted at least in the axial direction parallel to the axis FA.
Provided on the edge or frame 16.1 of the ejection window 16 are emission area shapers 26, examples of which include flaps, lugs, and/or slides. To prevent any adhesion or caking-on of the application liquid, the frame 16.1 and the emission area shapers 26 are provided with an anti-adhesion coating and/or the edge of the ejection window 16 is formed by a replaceable frame, for example a single-use or disposable frame 16.1. Fitting with a format part for an improved jet or spray mist distribution is also possible.
In addition to this normal mode for applying the application liquid to the treatment surface 2, the dampening unit 1 is also designed to be used during an automatic cleaning mode. In this mode, the collecting beaker 19 is moved into its upper end position so that it not only completely encloses the brush chamber 14 but also bears with its upper edge in a sealed manner against the underside of the bearing element 10. In this fully closed state, any residue of application liquid that is still present is pumped off from the collecting beaker 19 into a residue container. A suitable liquid cleaning medium, for example isopropanol, is then introduced into the collecting beaker 19 until the interior of the collecting beaker 19 is sufficiently filled, for example until it is 90% to 95% filled with this cleaning medium. Via control valves, the connection 13 is then connected to an output of the pump 25 so that, as the brush 3 rotates, the liquid cleaning medium is conveyed in a circuit from the collecting beaker 19 via the connection 13, the channel 9.1, the distributor channel 6.1 and the channels 12, thereby achieving intensive cleaning of the dampening unit 1. Because of the rotation of the brush 3, the cleaning is also mechanically assisted. Residues, particularly including any layers of application liquid on the inner surface of the brush chamber 14 and of the collecting beaker 19, are dissolved. Once the cleaning is finished, the cleaning fluid is pumped off into the residue container and the dampening unit 1 is opened for drying by lowering the collecting beaker 19.
It is possible to repeat the cleaning process at least one more time using a fresh liquid cleaning medium.
Finally,
The embodiments shown in
In an alternative variant (not shown), the container 33 or object to be coated is stationary, i.e. is not rotated about its axis, and the dampening unit 1 moves around the container 33 or object. In such an embodiment, the fluid is supplied to the dampening unit 1 via suitable rotary distributors.
During the application of the application liquid, i.e. during the production of the base layer or separating layer, the container 33 provided at a treatment position 32 is rotated about its container axis BA by a drive that acts, for example, on the container carrier 35 so that the entire circumferential region of the container 33 that is to be provided with the base layer or separating layer 34 is moved past the dampening unit 1 or past the ejection window 16 oriented with its longitudinal extent parallel to the container axis. The width of the base layer or separating layer 34 in the direction of the container axis can be adjusted by raising and lowering the collecting beaker 19 of the dampening unit 1. All of the dampening units 1 are supplied with the application liquid from a common tank 41, to which the connections 13 of the dampening units 1 of all the treatment positions 32 are connected via connecting lines and at least one rotary connection or one rotary distributor. In an analogous manner, for cleaning the dampening units 1, a common tank 42 for the cleaning fluid and a common residue tank 43 for collecting residues of the application liquid and used cleaning fluid are present.
The application of the respective features to the base layer and separating layer 34 takes place in a further container handling machine (not shown) or else in the container handling machine 30, wherein then the individual treatment positions 32 also have a printing unit in addition to the dampening unit 1 or else at least one assembly that does not move with the rotor 31 and that is designed to apply the features to the containers 33 is provided on the movement path of the treatment positions 32 moving with the rotor 31.
The invention has been described above on the basis of examples of embodiments. It will be understood that numerous changes and modifications are possible without thereby departing from the inventive concept on which the invention is based.
For instance, it is possible that the the application liquid is supplied to the brush 3 with nozzles on a nozzle element or nozzle carrier against which the bristles of the rotating brush 3 run and that is designed, for example, as a rubbing and wetting plate for the brush 3.
Furthermore, means for heating the application liquid supplied to the brush 3 may be provided.
Number | Date | Country | Kind |
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10 2012 004 972 | Mar 2012 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2013/000494 | 2/21/2013 | WO | 00 |
Publishing Document | Publishing Date | Country | Kind |
---|---|---|---|
WO2013/135341 | 9/19/2013 | WO | A |
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Number | Date | Country | |
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20150020733 A1 | Jan 2015 | US |