3D Composite Doctor Blade Structure for Delamination Resistance
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Solution Overview
Problem
Existing doctor blades and top plates in papermaking machines suffer from delamination and failure under extreme conditions due to chemical bonds failing between individual layers of 2-Dimensional reinforcement fabrics, leading to reduced performance and durability.
Innovation Solution
A doctor blade or top plate constructed with a single 3-Dimensional composite reinforcement fabric, where fibers are interlocked through stitching or weaving, providing enhanced mechanical binding and resistance to delamination, and incorporating nanoparticles for homogeneous distribution and improved properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If multiple individual layers of 2-Dimensional reinforcement fabric are bonded together with polymeric resin, then the doctor blade achieves required stiffness and strength, but the chemical bonds between layers fail under extreme conditions causing delamination and reduced durability
Solution Approach 1:
The patent transitions from bonding multiple 2-Dimensional fabric layers together to using a single 3-Dimensional woven fabric structure. This dimensional change eliminates the interfaces between layers where delamination occurs, while the 3-D weaving pattern provides reinforcement in multiple directions simultaneously, achieving the required stiffness and strength without the delamination problem.
Solution Approach 2:
The patent employs a composite structure combining 3-Dimensional woven fabric with specific polymeric resin systems. The 3-D fabric provides the structural framework with interlaced yarns in multiple orientations, while the resin matrix binds the fabric structure and provides additional mechanical properties. This composite approach delivers both the required strength and improved durability by eliminating layer interfaces.
2Volume of moving object
If 8 layers of 200gsm plain weave 2-D glass fabric are bonded together to produce a 1.5mm thick doctor blade, then the blade achieves adequate thickness and strength, but the multi-layer structure is prone to delamination under harsh operating conditions
Solution Approach 1:
The patent replaces the multi-layer 2-D fabric construction with a single 3-D woven fabric structure. The 3-D weaving process creates yarns that interlace in the thickness direction, providing structural integrity throughout the blade thickness without requiring multiple bonded layers. This achieves the required 1.5mm thickness with a monolithic structure that resists delamination.
3Duration of action of stationary object
If carbon fibres are used to improve wear life and stiffness, then the doctor blade achieves enhanced performance, but the 2-D layer structure still suffers from chemical bond failure between layers
Solution Approach 1:
The patent integrates carbon fibres into a 3-D woven fabric structure where the fibres are interlaced with glass fibres in multiple orientations. This composite fabric structure provides the wear resistance and stiffness benefits of carbon fibres while the 3-D weaving architecture eliminates the layer interfaces that cause delamination, maintaining structural integrity throughout the service life.
Data Source
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AI summary
A planar element is disclosed for use in a papermaking system. The planar element is suitable for use as a doctor blade or a top plate and includes a three-dimensional composite structure including elongated elements extending in at least three orthogonal directions, and a resin in which the three-dimensional composite structure is embedded.