Green Veneer Dewatering via Variable Pressure
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Solution Overview
Problem
Existing dewatering methods for green veneers in plywood production fail to effectively reduce variability in water content among and within individual veneers, leading to lengthy drying times and potential warp or distortion in the final product.
Innovation Solution
A method and apparatus that vertically laminate green veneers, apply a pressing force to compress and dewater them, and utilize a cycle of pressure release to create negative pressure, allowing water to be transferred from high-water-content areas to low-water-content areas, thereby reducing water content variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If green veneers are compressed and dewatered by applying uniform pressure, then dewatering efficiency is improved, but water content variability among and within veneers increases
Solution Approach 1:
The patent applies different pressing forces to different regions of the veneer stack. High-water-content regions (such as sapwood areas) receive higher pressing forces, while low-water-content regions (such as core areas) receive lower pressing forces. This localized differentiation of pressing intensity corrects water content variability rather than uniformly compressing all veneers, thereby resolving the contradiction between dewatering efficiency and water content uniformity.
Solution Approach 2:
The patent employs a dynamic pressing mechanism that can adjust pressing forces during the dewatering process. The pressing system transitions from initial uniform compression to subsequent differentiated pressing based on real-time monitoring of water content distribution. This dynamic adjustment allows the system to maintain high dewatering efficiency while progressively correcting water content variability among and within veneers.
2Manufacturing precision
If green veneers are dried immediately after peeling, then water content uniformity is improved, but production time increases
Solution Approach 1:
The patent implements preliminary dewatering by compression before the formal drying step. By removing a significant portion of free water through mechanical pressing during veneer production, the subsequent drying process only needs to remove bound water, which dramatically reduces drying time while maintaining water content uniformity. This preliminary water removal action resolves the contradiction between achieving uniform water content and minimizing production time.
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 approach efficiently reduces water content variability among and within veneers, ensuring more uniform drying and minimizing the likelihood of warp or distortion in the plywood, thereby improving the production process.
Implementation Method 1
a pressing member provided in an upper part of the support platen and movable toward and away from the support platen; the pressing member being adapted to apply pressing force to the veneer laminate
Implementation Method 2
the application of the pressing force being released or weakened while the water contained in the veneer laminate is being discharged from the veneer laminate
Data Source
AI summary
A large number of green veneers for plywood respectively having high water contents and formed in a rectangular shape are vertically laminated to obtain a veneer laminate having a quadrangular prismatic shape. The veneer laminate is located between upper and lower platen members so that two opposite side faces of the veneer laminate vertically form cut face gathering planes. The upper and lower platen members are moved toward each other to apply a pressing force to the veneer laminate. The pressing force applied to the veneer laminate is released or weakened while the water drawn through the cut face gathering planes by the pressing force is dripping downward along the cut face gathering planes of the veneer laminate vertically formed.