Fibrous Web Machine with Double-Felted and Single-Felted Shoe Presses
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Solution Overview
Problem
Existing machines for producing packaging paper and cardboard face challenges in achieving high smoothing effects, maintaining web strength, and efficient dewatering at speeds above 1000 m/min, while minimizing production downtime and costs, particularly due to issues with open draws, web tension, and inefficient dewatering processes.
Innovation Solution
A machine design incorporating at least one double-felted shoe press followed by a single-felted shoe press, optimized for high smoothing and compaction, with a transfer belt system to minimize web tension and enable safe, fast transfer, and a single pulper for waste management, ensuring gentle dewatering across multiple nips.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If an offset press is used for smoothing, then smoothing effect is improved, but web strength deteriorates due to high tension and long open draws
Solution Approach 1:
A felt is introduced as an intermediary carrier between the smoothing press and the dryer section. The felt supports the web during transfer, eliminating the need for long open draws through air and gravity. This mediator prevents web tension and tearing while maintaining the smoothing effect achieved by the offset press.
Solution Approach 2:
The process is segmented into distinct zones: the smoothing press applies pressure for surface quality, then the felt immediately supports the web for transfer. This segmentation allows the smoothing function to operate independently without subjecting the web to prolonged tension, preserving both smoothing effect and web strength.
2Productivity
If web speed is increased above 1000 m/min, then productivity is improved, but web stability deteriorates due to high tension and tearing risk
Solution Approach 1:
The felt acts as a mediator that enables high-speed operation by providing continuous support to the web. At speeds above 1000 m/min, the felt's mechanical support prevents web instability, tearing, and defects that would otherwise occur during rapid acceleration and transfer through open draws.
3Quantity of substance
If multiple pulpers are used for waste management, then waste handling capacity is improved, but device complexity increases
Solution Approach 1:
Multiple pulpers are merged into a single pulper system. The felt carrier enables consolidated waste collection from all press positions into one pulper, reducing device complexity while maintaining adequate waste handling capacity through centralized processing.
4Stability of the object's composition
If felt is used for smoothing press, then web support is improved, but surface quality deteriorates due to felt texture
Solution Approach 1:
Different felt qualities are applied locally: a smooth felt is used specifically in the smoothing press contact zone to maintain surface quality, while other felt sections can have different properties optimized for their specific functions such as web support or dewatering. This local differentiation resolves the contradiction between support and surface quality.
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
Achieves high smoothing and compaction effects, maintains web strength, allows for speeds up to 1000 m/min, reduces production downtime, and minimizes costs by simplifying web transfer and dewatering processes.
Implementation Method 1
separation of the clothing or felts of a double-felted shoe press in the web running direction after a shoe press nip is carried out by means of a suction felt guide roller, which is arranged in particular in the loop of the bottom felt
Implementation Method 2
Each shoe press (42, 44) comprises an upper shoe press roll (46) and a lower counter roll (48)... optimized for high smoothing and compaction
Data Source
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AI summary
The invention relates to a machine for producing a fibrous material web, in particular a packaging paper or cardboard web. The machine comprises at least one, preferably two, double-felted shoe presses mounted one behind the other in the direction of movement of the web, and at least one single-felted shoe press mounted downstream of the two double-felted shoe presses in the direction of movement, particularly in the form of a smoothing press.