Printing – Antismut device
Reexamination Certificate
1999-03-22
2001-04-24
Asher, Kimberly (Department: 2854)
Printing
Antismut device
C101S424100, C101S480000, C492S046000
Reexamination Certificate
active
06220161
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention of the instant application relates to a chill roller for use in the graphic arts industry, in particular for cooling a printed web of material in a rotary printing press.
U.S. Pat. No. 4,920,881 discloses a method of cooling hot webs of material. This disclosure is related to a method for cooling a hot web by passing it across a rotating thermally conductive chill roller having a recirculating coolant therein. In accordance with U.S. Pat. No. 4,920,881, a liquid refrigerant at a temperature and pressure permitting the refrigerant to exist in liquid form is introduced as a coolant to the chill roller, the temperature being also above the dew point of the ambient atmosphere. Likewise, the boiling point of the refrigerant at the desired temperature and pressure is low enough to cause heat to be absorbed by the chill roller primarily by vaporization of the liquid refrigerant. Refrigerant vapor is then withdrawn from the chill roller and is typically refrigerated to reform the liquid phase for return to the chill roller. Typically, chlorofluorcarbon refrigerants are preferred.
The published European Patent Document EP 0 468 219 A1 discloses a chill stand within which a plurality of chill rollers are mounted in a chill roller stand. Wit h this construction, boundary layers of ambient air and oil vapor adhering to both sides of the passing web of material are dissipated while the web of material moves through the chill stand. The chill rollers are mounted on frames, which can be adjusted with respect to one another. By a movement of the respective frames, the chill roller adopts positions in which portions of the moving web being transported in opposite directions around respective chill rollers are kept at a narrow distance from one another to create a boundary layer destroying zone. The boundary layer adhering to those portions of the web of material kept at a narrow distance with respect to one another are dissipated within the boundary layer dissipating zone.
The published European Patent Document EP 0 346 046 A2 discloses a chill roller. This document relates to a chill roller for cooling a web, a printed web of material such as in the graphic arts industry, where a uniform temperature across the chill roller is maintained. Journals support an outer roller assembly and an inner roller assembly. The inner roller assembly is bearing mounted on the inner ends of opposing journals and the outer roll is rotated about the inner roller, which is weighted to free-wheel about the bearings to minimize rotary motion. Coolant is introduced through the journal on one end and into a center tube, where the coolant uniformly flows in an annular space between the rollers and along the length of the inner and outer roller assemblies to circumferentially traverse between the rotating and stationary outer and inner rolls. This coolant flow provides enhanced heat transfer from the outer rotating chill roller to the circulating coolant. Heated coolant collects and returns through a center tube and exhausts through the center tube and out through the journal. Turbulence inducer bars between the inner and outer roller assemblies create a turbulence in the coolant flow between the outer and inner rollers to further enhance heat transfer.
Heretofore, double wall steel cooling rollers with and without a spiral have been in use. The spiral has been constructed to move the water at an even rate between the outer and the inner wall of a cooling roller. However, despite the use of the spiral with the cooling roller, there still remains the problem of an inhomogeneous heat transfer on a cooling roller causing the significant problem of a web drift due to changes, even slight changes, in the diameter of the chill rollers caused by temperature differences. Furthermore, the provided solution of double wall cooling rollers offers little or no possibility at all for a temperature adjustment.
Efforts have been made to ease the major drawbacks of the aforementioned double wall cooling rollers by having a plurality of cooling water circuits connected to the chill roller stand to provide coolants with a different temperature level. Additionally, cooling water bypasses have been constructed having a pump or three-way valves and the corresponding bypass-piping systems. The additional costs involved with these efforts and the outcome thereof have not justified the approaches taken to address the problem in this manner.
SUMMARY OF THE INVENTION
Taking the state of the art as outlined above into consideration, it is accordingly an object of the invention to provide a chill roller having readily adjustable temperatures. A further object of the invention is to prevent the occurrence of oil condensate on the surfaces of a respective chill roller.
With the foregoing and other objects in view, there is provided, in accordance with one aspect of the invention, a chill roller having in the interior thereof structural features selected from groups thereof consisting of mixing zones and transport pipes, and having at the exterior thereof a coolant supply pipe and a coolant discharge pipe, comprising coolant supplied through the coolant supply pipe to the structural features simultaneously for forming a uniform temperature profile over the entire length of one of the chill roller and a surface of a cylinder jacket thereof.
In accordance with another feature of the invention, the mixing zones are connected in series.
In accordance with a further feature of the invention, the mixing zones are connected to a central distribution pipe.
In accordance with an added feature of the invention, the mixing zones have a temperature therein equal to the temperature in the central distribution pipe.
In accordance with an additional feature of the invention, central distribution pipe is fixed to a first end face of the chill roller.
In accordance with yet another feature of the invention, the central distribution pipe is formed with a plurality of outlet openings assigned to the mixing zones.
In accordance with yet a further feature of the invention, the outlet openings are annular openings.
In accordance with a first alternative feature of the invention, the outlet openings are bores.
In accordance with a second alternative feature of the invention, the outlet openings are perforations formed in the central distribution pipe.
In accordance with yet an added feature of the invention, the outlet openings, respectively, have a cross section that increases over the length of the chill roller.
In accordance with yet an additional feature of the invention, the mixing zones are separated from one another by partitions.
In accordance with still another feature of the invention, the partitions, respectively, have an annular shape.
In accordance with still a further feature of the invention, the partitions are circular plates.
In accordance with still an added feature of the invention, the respective mixing zones are provided with respective coolant outlets formed between the surface of the cylinder jacket and the respective partitions.
In accordance with still an additional feature of the invention, the respective coolant outlets of the mixing zones have respective cross sections which increase over the length of the surface of the cylinder jacket of the chill roller.
In accordance with another feature of the invention, a plurality of the transport pipes are distributed in annular form within the hollow interior of the chill roller.
In accordance with a further feature of the invention, a coolant flow emerging from the transport pipes contacts the surface of the cylinder jacket of the chill roller simultaneously over the length thereof.
In accordance with another aspect of the invention, there is provided a chill roller stand comprising a plurality of chill rollers, respectively, having in the interior thereof structural features selected from groups thereof consisting of mixing zones and transport pipes, and having at the exterior thereof a coolant supply pipe and a coolant discharge pipe,
Asher Kimberly
Greenberg Laurence A.
Heidelberger Druckmaschinen Aktiengesellschaft
Lerner Herbert L.
Stemer Werner H.
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