Blade Angle for Edge Strip Separation in Fourdrinier Machines
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Solution Overview
Problem
Existing sheet forming devices for fourdrinier machines face challenges in reliably cutting off edge strips without generating edge waves or accumulations of material in the fibrous suspension, leading to manufacturing errors in paper, cardboard, or packaging paper production.
Innovation Solution
The device incorporates a blade with a first blade area aligned at an angle of 3° to 15° to the fourdrinier wire, with a trailing distance of at least 20 mm, and a second blade area that can be omitted, allowing for a long cutting edge that gently separates the edge trim, preventing accumulation and ensuring reliable edge removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a conventional blade configuration is used for edge strip separation, then the edge strip can be cut off, but edge waves and material accumulations occur in the fibrous suspension
Solution Approach 1:
The blade is divided into multiple blade areas with different angles and functions. The first blade area (3°-15°) gently separates the edge strip, while the second blade area (80°-100°) completes the separation. This segmentation allows each area to perform its specific function optimally, preventing edge waves and material accumulations while achieving clean edge strip removal.
Solution Approach 2:
Different portions of the blade have different geometric properties tailored to their specific functions. The first blade area has a small angle for gentle separation, while the second blade area has a large angle for complete separation. This local differentiation of geometric quality enables precise control over the separation process, eliminating harmful effects.
2Productivity
If the blade cuts through the fibrous suspension quickly, then productivity is improved, but material accumulations and edge waves are generated
Solution Approach 1:
The cutting action is segmented into two distinct phases: first blade area for gentle separation and second blade area for complete separation. This segmentation allows the system to maintain high productivity while preventing material accumulations by ensuring complete separation in a controlled manner.
Solution Approach 2:
The first blade area performs preliminary separation of the edge strip from the fibrous suspension before the second blade area completes the separation. This preliminary action prevents material accumulations by initiating the separation process early, allowing the fibrous suspension to flow smoothly without buildup.
3Manufacturing precision
If a sharp cutting edge is used, then edge strip separation is effective, but fiber build-up occurs on the blade
Solution Approach 1:
The blade is segmented into multiple areas with different angles. The first blade area (3°-15°) uses a smaller angle to gently separate the edge strip without creating a sharp cutting edge that would cause fiber build-up. The second blade area (80°-100°) completes the separation. This segmentation allows effective edge strip separation while minimizing fiber accumulation on the blade.
Solution Approach 2:
The first blade area has a specific local quality (small angle) that prevents fiber build-up while maintaining separation effectiveness. The second blade area has a different local quality (large angle) for completing the separation. This local differentiation of geometric properties ensures effective separation without the harmful fiber accumulation associated with sharp edges.
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 configuration enables improved and process-reliable separation of the edge trim without edge waves or material accumulations, ensuring high-quality production by preventing fiber build-up and allowing for efficient fiber recycling, thus enhancing the quality of the fibrous web.
Implementation Method 1
a means for separating the edge strip (16) comprises a blade (19), which consists of at least a first blade area (19.1)
Data Source
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AI summary
The invention relates to a sheet forming device (1) for a Fourdrinier machine (100) for producing a web of fibrous material (2), in particular a web of paper, card or packaging paper, from at least one fibrous material suspension (3). The sheet forming device (1) comprises at least one circulating endless wire (4), a headbox (6), which produces a machine-wide jet (J) of fibrous material suspension by way of a headbox nozzle (7) and applies it to the endless wire (4), and two format-delimiting units (13), respectively attached both in the peripheral region of the endless wire (4) and in the region of the jet (J) of fibrous material suspension, wherein the format-delimiting units (13) respectively have on the starting side at least one means (16) for detaching a peripheral strip (17) and on the outer side, and preferably directly downstream of the means (16) for detaching the peripheral strip (17), a means (18) for carrying away the detached peripheral strip (17). The invention is distinguished by the fact that the means (16) for detaching the peripheral strip (17) comprises a blade (19), consisting at least of a first blade region (19.1) and aligned in the running direction (L) of the endless wire, wherein the blade (19) has in relation to the endless wire an angle (W1) opening in the running direction (L) of the endless wire that lies in the range of 3° to 15°.