Sheet-fed Printing Press Dryer Cooling Module for Sheet Flatness
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Solution Overview
Problem
Sheet-fed printing machines with non-impact printing devices face issues with sheets bulging and losing adhesion during drying, leading to unreliable transport and potential operational disruptions due to inadequate suction force and heat-induced deformation.
Innovation Solution
A sheet-fed printing machine design incorporating a dryer with a cooling device immediately downstream, utilizing a conveyor belt system and infrared radiation sources to efficiently dry and cool sheets, maintaining flatness and preventing bulging, along with a control system to adjust dryer output and cooling capacity based on sheet temperature and moisture content.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If sheets are dried using a dryer with conveyor belt and suction device, then drying efficiency is improved, but sheets bulge and lose adhesion due to heat-induced deformation and inadequate suction force
Solution Approach 1:
A cooling device is positioned immediately downstream of the dryer to cool sheets before they reach the transport conveyor. This preliminary cooling action prevents heat-induced bulging and maintains sheet flatness, ensuring reliable transport. The cooling device acts in advance to eliminate the harmful thermal effects before they compromise transport reliability.
Solution Approach 2:
The cooling device serves as an intermediary element between the dryer and the transport conveyor. It mediates the thermal transition by cooling the sheets after drying but before transport, preventing direct contact between hot sheets and the transport system. This intermediary cooling zone resolves the contradiction by decoupling the drying heat from the transport requirements.
2Productivity
If dryer temperature is increased to improve drying speed, then productivity increases, but heat energy transfer to downstream components increases causing condensation
Solution Approach 1:
The cooling device extracts excess heat energy from the sheets immediately after drying. By positioning the cooling device downstream of the dryer, it removes the harmful thermal energy before the sheets reach downstream components. This extraction of heat prevents condensation on downstream equipment while maintaining high drying speeds in the dryer.
Solution Approach 2:
The cooling device converts the harmful excess heat into a beneficial controlled cooling process. The heat that would otherwise cause condensation and damage is now utilized in a controlled manner to gradually cool the sheets. This transforms the harmful thermal energy into a useful cooling function, eliminating condensation issues while maintaining drying productivity.
3Manufacturing precision
If suction force is increased to prevent sheet bulging, then sheet flatness is improved, but energy consumption increases
Solution Approach 1:
The cooling device is positioned immediately downstream of the dryer to cool sheets before they enter the transport phase. This preliminary cooling prevents heat-induced expansion and bulging, eliminating the need for high suction forces during transport. By cooling sheets in advance, the system maintains sheet flatness with minimal energy consumption.
Solution Approach 2:
The cooling device replaces the mechanical suction force with a thermal solution. Instead of using high-energy suction to prevent bulging, the system uses cooling to maintain sheet dimensional stability. This substitution of mechanical action (suction) with thermal action (cooling) achieves the same flatness result with significantly lower energy consumption.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
Ensures reliable further transport of sheets by preventing bulging and maintaining flatness, reducing heat energy transfer to downstream components, and minimizing condensation, thereby enhancing operational efficiency and preventing damage to printed images.
Implementation Method 1
at least one drying module (54) having, on its side facing the surface of the sheet (64) to be dried, which is moved through the sheet-fed printing press in the transport direction (T), a guide surface (61) extending over a linear drying section, with a plurality of nozzles (62), each of these nozzles (62) having an opening cross-section through which, or at least through which, hot air flows
Implementation Method 2
A sheet-fed printing machine design incorporating a dryer with a cooling device immediately downstream, utilizing a conveyor belt system and infrared radiation sources to efficiently dry and cool sheets, maintaining flatness and preventing bulging
Implementation Method 3
While resting on the at least one conveyor belt, the individual sheets are held in place by a suction force, i.e., by a holding force caused by a suction flow, in a frictional or force-fit manner
Implementation Method 4
The suction force is typically This is achieved by applying a vacuum to the respective arc, adjusted with reference to the surrounding barometric air pressure by means of a suction device
Data Source
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AI summary
The invention relates to a sheet-fed printing press having a dryer (17) for drying sheets (64) printed by a non-impact printing device (13), the dryer (17) being designed as a hot air dryer and/or as a dryer for drying by IR radiation, wherein: a cooling device (36) is disposed directly downstream of the dryer (17) in the transport direction (T) of the sheets (64); the cooling device (36) has at least one cooling module (37) above a conveying plane (E) in which the sheets (64) are conveyed in a flat state through the cooling device (36); the relevant cooling module (37) is designed in such a way that it uses air as a cooling medium; each of the cooling modules (37) of the cooling device (36) is designed as a blower box (41); each blower box (41) is designed to direct the cooling medium onto the surface of each of the sheets (64) to be cooled; each blower box (41) has blowing nozzles (43); the cooling medium is blown by these blowing nozzles (43) onto the surface of the particular sheet (64) to be cooled; each blower box (41) is designed in such a way that it forms a gap (S37) with a guide face (42) to the surface of the relevant sheet (64) to be cooled; the guide face (42) of the relevant blower body (41) is disposed at such a height above the surface of the relevant sheet (64) to be cooled that the cross-section of an outer annular gap through which a volume flow of the cooling medium exits the gap (S37) is smaller than or almost equal to the total cross-section over all opening faces of the blowing nozzles (43) in the guide face (42).