Patent Application
20080060537
In the following, preferred examples of the invention are explained in greater detail by means of the drawing, in which
The installation, shown in
In order to achieve an optimum printing result, the dampening solution 14 is cooled to a specified process temperature. For this purpose, a portion of the dampening solution, circulating in the dampening solution cycle 18, is diverted through a secondary pipeline 28 out of the inlet 20 of the printing press 12 and supplied to a cooling unit 30. The dampening solution, cooled by the cooling unit 30, is passed through a return pipeline 32 back into the dampening solution tank. The temperature of the dampening solution 14 in the dampening solution tank 16 can be controlled by the cooling performance of the dampening solution cooling unit 30 and by the proportion of dampening solution, which is diverted through the secondary pipeline 28 from the inlet 20 of the printing press 12. Typically, this temperature is constant, ranging from about 6° to 12° C. with a tolerance of ±1° C. and preferably of ±0.5° C. Fluctuations of the temperature in the dampening solution cycle 18 can be equalized by a control segment, which is not shown and extends between the cooling unit 30 and the tank 16 of the dampening solution. The output of the cooling unit 30 is increased if the temperature of the dampening solution 14, which is stored in the dampening solution tank 16, increases. Alternatively, the proportion of dampening solution, diverted to the cooling unit 30, can be increased. Furthermore, it is possible to measure the actual temperature of the dampening solution by means of a sensor at a different place in the dampening solution cycle 18, for example, directly in the region of the printing roller.
During the printing process, dampening solution is consumed, so that the amount of dampening solution 14, kept in the dampening solution tank 16, gradually becomes less. This loss is compensated for in that the basic liquid materials for producing new dampening solution are supplied to the device for preparing dampening solution through a feeding device, which is generally labeled 40 in
The basic material 42 is passed through a basic material feed line 44 into a prechamber 46. The basic material feed line 44 comprises a shut-off valve 48, which permits the material, flowing through the feed line 44, to be controlled or the latter to be shut off completely.
In the example shown here, the prechamber 46 and the dampening solution tank 16 are located in a single container 50 and are separated from one another by a partition 52. If the prechamber 46 is filled over the basic material feed line 44, the basic material 42 can flow over an overflow 54 in the upper region of the partition 52 out of the prechamber 46 into the dampening solution tank 16. If several basic material feed lines 44 for different basic materials, such as water, alcohol and the like, discharge into the prechamber 46, then a mixture of basic materials, which forms the dampening solution, is already present within the prechamber 46. In the strict sense of the word, the present invention therefore relates not only to a pre-cooling of individual basic materials, but also to the pre-cooling of a mixture of basic materials, which forms a dampening solution kept within the pre-chamber 46 and is passed into the dampening solution tank 16 in the pre-cooled state and is available there to the above-described dampening solution cycle 18.
In the example shown here, this pre-cooling takes place due to the thermal coupling between the pre-chamber 46 and the dampening solution tank 16, which are separated from one another only by the partition 52 within the tank 50. Accordingly, the basic material 42 or the mixture of basic materials within the prechamber 46 is cooled through the partition 52 by the dampening solution 14 in the dampening solution tank 16, which is cooled constantly to the process temperature by the dampening solution cooling unit 30. By these means, excessive temperature fluctuations, which cannot be equalized in good time due to the inertia of the control system of the cooling unit 30, are avoided when the dampening solution tank 16 is filled with basic materials or the dampening solution mixture from the prechamber 46. The process temperature of the dampening solution can therefore also be kept largely constant also during the refilling process.
The prechamber 46 can also be coupled thermally with the dampening solution tank 16 in other ways. For example, the prechamber 46 may be constructed as an independent container, one wall of which is in contact with the outer wall of the dampening solution tank 16. Furthermore, it is conceivable to construct the prechamber 46 in such a way, that it is surrounded at least partly by the dampening solution tank 16.
The feeding device 70 of the installation for preparing dampening solution in
In a further embodiment, not shown in the Figures, the basic material can be passed through a coil around the dampening solution tank, so that it is coupled thermally with the latter. Before the basic material flows out of the end of the coil into the dampening solution tank 16, it is accordingly cooled through the outer wall of the dampening solution tank 16. The coil, in much the same way as the prechamber 46, forms a buffer, in which a flowing volume of basic material, which is coupled thermally with the dampening solution 14 within the dampening solution tank 16, is pre-cooled by the latter.
In all the embodiment shown here, it is possible to integrate the device 10, 62, 72 for preparing the dampening solution, which is connected by the dampening solution cycle 18 with the printing press 12, and the feeding device 40, 60, 70 in a peripheral device, which is to be made available to a printing press, so that a space-saving and compact construction is attained.
| Number | Date | Country | Kind |
|---|---|---|---|
| 10 2006 042 091.8 | Sep 2006 | DE | national |
