Expandable Deckle Board Microstructure Turbulence
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Solution Overview
Problem
Existing deckle board systems in paper machines face issues with maintaining a consistent width, preventing waves in the cross-machine direction, and ensuring edge consistency due to uneven stock distribution and thermal expansion, leading to reduced paper production efficiency and increased rejection rates.
Innovation Solution
The implementation of a deckle board system with a microstructure on the stock side that generates turbulent flow to break up the boundary layer, combined with adjustable and expandable deckle boards connected via vertical and horizontal stands, and a shower system to maintain a clean and even water curtain, ensuring consistent stock retention and edge formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a static board is used to retain stock on the wire, then stock retention is improved, but the width of the paper machine decreases resulting in less tons per hour
Solution Approach 1:
The deckle board is made expandable through a system of vertical stands with telescoping inner and outer tubes, allowing the board to dynamically adjust its width. This enables the deckle board to maintain full width for maximum productivity while still providing effective stock retention when needed, resolving the contradiction between stock retention reliability and production capacity
2Shape
If stock is pushed along the cross machine direction to form edges, then edge formation is achieved, but uneven formation occurs along the edges and center leading to sheet rejection
Solution Approach 1:
A microstructure is applied specifically to the stock side surface of the deckle board, creating localized turbulence only where stock contact occurs. This microstructure generates controlled eddies and mixing action at the edges without affecting the overall uniformity of the sheet formation, achieving proper edge formation while maintaining consistent quality across the entire sheet
3Device complexity
If the deckle board remains static, then结构简单性 is maintained, but the deckle board cannot remain planar as temperatures vary along the paper machine
Solution Approach 1:
The vertical stands incorporate telescoping inner and outer tubes that allow the deckle board to expand and contract dynamically in response to thermal conditions. This dynamic adjustment mechanism maintains the board's planarity across varying temperatures without requiring complex active control systems, balancing structural simplicity with thermal stability
Solution Approach 2:
The expandable stand structure is designed to accommodate thermal expansion and contraction of the deckle board. As temperatures vary along the paper machine, the telescoping tubes allow the board to change dimensions while maintaining its planar configuration, preventing warping and distortion
4Shape
If water is used to cut stock and form edges, then edge formation is achieved, but waves are sent from one side of the paper machine towards the other side
Solution Approach 1:
The microstructure on the stock side creates localized turbulence and mixing action precisely where stock contact occurs at the edges. This localized action forms clean edges without generating the large-scale waves that propagate across the sheet, as the turbulence is confined to the immediate vicinity of the deckle board surface
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 maximizes paper machine width utilization, prevents waves, and maintains edge consistency across varying temperatures, enhancing production efficiency and reducing paper rejection rates by ensuring a uniform deckle edge and consistent basis weight.
Implementation Method 1
the stock side includes a microstructure that generates turbulent flow along a face of the deckle board that breaks up a boundary layer when stock contacts the stock side of the deckle board
Data Source
AI summary
A system comprising: one or more deckle board that are configured to extend along a machine direction of a paper machine and wherein the deckle board includes a stock side and a non-stock side and the stock side includes a microstructure that generates turbulent flow along a face of the deckle board that breaks up a boundary layer when stock contacts the stock side of the deckle board.