Former Air Blast and Suction Openings for Web Folding
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Solution Overview
Problem
Web-fed rotary printing machines face challenges in reducing the risk of smearing and air pocket formation during the folding of printed webs, leading to potential damage and increased friction, especially when handling extra-wide layers or newspaper products with multiple pages.
Innovation Solution
The implementation of a device with strategically placed air blast and suction openings along the funnel flanks and nose area of the former, allowing for controlled air flow to reduce friction and prevent air inclusion, which includes blowing air to reduce friction and using suction to remove air pockets, ensuring smooth folding without bag formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If air blast openings are provided in the funnel area to reduce friction during folding, then the friction in the folding area is reduced, but air pockets may form and cause smearing or damage to the printed strand
Solution Approach 1:
The former is divided into multiple functional zones with different air pressure characteristics: a first region with positive pressure (blowing air) to reduce friction, and a second region with negative pressure (suction) to remove air pockets. This segmentation allows simultaneous achievement of low friction and air pocket prevention in different areas of the folding process.
Solution Approach 2:
Different regions of the former are assigned different air pressure qualities: the funnel area receives positive pressure air blast to reduce friction, while the downstream area receives negative pressure suction to prevent air inclusion. Each region has optimized local air pressure characteristics suited to its specific function in the folding process.
2Object-affected harmful factors
If suction air openings are added to remove air pockets, then air inclusion and bag formation are prevented, but the device complexity increases
Solution Approach 1:
The blowing air device and suction device are merged into a single integrated former structure, with both positive and negative pressure air openings provided in the same component. This combining approach prevents air pockets without significantly increasing overall device complexity, as both functions are integrated into one unit rather than requiring separate devices.
3Ease of operation
If blowing air is used in the funnel area to assist folding, then folding assistance is improved, but smearing risk increases due to air pockets
Solution Approach 1:
The folding process is segmented into two functional zones: the funnel area with blowing air for folding assistance, and the downstream area with suction to prevent air pocket formation. This segmentation allows the benefits of air-assisted folding while preventing the harmful effects of air inclusion that would cause smearing.
Solution Approach 2:
The air pockets that would normally cause harm (smearing and damage) are converted into a beneficial outcome by using suction to actively remove them. The same air that provides folding assistance in the funnel area is subsequently removed in the suction area, preventing smearing while maintaining the folding benefits.
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
This solution effectively minimizes the risk of smearing and damage by maintaining low friction and preventing air pockets, enabling the production of high-quality, extra-wide newspaper products with reduced risk of air inclusions and bursting of glue lines.
Implementation Method 1
air blast openings (24) which interact with a web strand (25) to be folded and which open into one or more chambers (29) of the same chamber (29). These chambers (29) are at a positive pressure (P+)
Implementation Method 2
at least one suction opening (38) which opens facing the web strand (25) to be folded
Data Source
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AI summary
The invention relates to a device for a web-fed rotary printing press for processing one or more printed webs, comprising a former, a strand leaving said former, a cross-cutter device arranged downstream of the former in the strand course, as well as a strand path formed between the former and the cross-cutter device via at least one guiding element. On at least one longitudinal former section which extends in the transport direction, and in the region of both its right-hand and its left-hand former flanks, said former comprises blast-air openings which are fluidically-connected to a fluid line that conducts a fluid which is at a higher pressure than the ambient pressure. At least one suction opening, facing the web strand to be folded, is arranged on said former between a left-hand and a right-hand flank-side section which comprises blast-air openings, and/or upstream of blast-air openings that are provided in a projection region, and/or a suction opening of a nozzle engaging in the folded strand is provided in the strand path downstream of said former. The suction opening in question is fluidically-connected to a fluid line that conducts a fluid which is at a lower pressure than the ambient pressure.