Deckle Board Boundary Layer Shower for Paper Machine Edge Formation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing paper machine deckle systems face issues with inconsistent edge formation and reduced paper width due to stock being pushed from the edges, leading to waves and uneven paper quality, which results in rejected sheets and decreased production capacity.
Innovation Solution
A deckle board system with a boundary layer shower that directs fluid onto the stock side of the deckle boards to create a turbulent flow, preventing waves and ensuring a consistent boundary layer, while the deckle boards are designed with microstructures and guide grooves to maintain stock alignment and prevent buildup, allowing for thermal expansion without warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If water is used to cut the stock and form an edge on the wire, then an edge is created on the paper machine, but waves are sent from one side of the paper machine towards the other side, resulting in uneven formation and rejected sheets
Solution Approach 1:
A deckle board is introduced as an intermediary physical barrier between the stock and the wire edge. The deckle board prevents direct water-stock interaction that causes waves, while still allowing water to flow along its surface. This mediator maintains edge formation without generating the harmful waves that lead to formation inconsistencies.
Solution Approach 2:
The deckle board creates a controlled water flow pattern along its surface that replicates the desired edge formation without the disruptive wave patterns. By copying the beneficial edge-cutting function while eliminating the harmful wave generation, the deckle board achieves stable formation while maintaining proper edge definition.
2Shape
If stock is pushed along the cross machine direction to form an edge, then an edge is created, but inconsistencies are created along the edges and towards the center of the sheet, leading to rejected paper
Solution Approach 1:
The deckle board serves as a mediator that defines the edge position without directly pushing stock. Instead of mechanical pushing that creates inconsistencies, the deckle board allows water to flow along its surface, gently guiding stock to the edge position while maintaining uniform formation across the sheet width.
3Reliability
If a static board is used to prevent stock from exiting the wire, then stock retention is improved, but the width of the paper machine is reduced, decreasing tons per hour production
Solution Approach 1:
The deckle board copies the stock retention function of a static board but with a different mechanism. Instead of relying on the board's physical presence to block stock, it uses controlled water flow along the board surface to guide stock retention, allowing the wire to maintain its full width and production capacity while still achieving effective stock retention.
4Reliability
If the deckle board remains fixed in position, then stock retention is maintained, but thermal expansion causes the board to warp and become non-planar, affecting performance
Solution Approach 1:
The deckle board system transitions from a static fixed structure to a dynamic adjustable structure. The board can now move or adjust its position in response to thermal expansion, maintaining planarity through controlled movement rather than rigid fixation. This dynamic capability allows the board to compensate for thermal effects while preserving stock retention performance.
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
The system maximizes paper machine width, reduces edge inconsistencies, and prevents wave propagation, resulting in improved paper quality and increased production efficiency by maintaining a planar deckle board configuration even with varying temperatures.
Implementation Method 1
directs a fluid unto a stock side face of the one or more deckle boards so that a boundary layer of fluid is formed between the one or more deckle boards and stock
Implementation Method 2
the one or more guide grooves are configured to receive a slide, a T-nut, or both that is movable along the one or more guide grooves, allows movement of the deckle boards in the machine direction
Data Source
AI summary
A system comprising: one or more deckle board that extend along a machine direction of a paper machine, and a boundary layer shower that is located proximate to each of the one or more deckle board systems and directs a fluid unto a stock side face of the one or more deckle boards so that a boundary layer of fluid is formed between the one or more deckle boards and stock.