Wet-on-Wet Spreading Roller Casing to Prevent Delamination
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Solution Overview
Problem
Spreading rollers in machines for producing fibrous webs, such as papermaking, experience premature wear and delamination of multi-layer casings due to high friction and humid conditions, leading to reduced service life and increased manufacturing effort.
Innovation Solution
A method of manufacturing a casing for spreading rollers by simultaneously producing two polymer layers and embedding a reinforcing structure within the first layer, using a rotational molding process where the polymers are applied 'wet-on-wet' and the reinforcing structure is embedded before the second layer is applied, resulting in improved adhesion and reduced delamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If multi-layer casings are used for spreading rollers, then the service life can be extended, but delamination of individual layers occurs during normal machine operation
Solution Approach 1:
The patent combines multiple polymer layers into a single monolithic structure through simultaneous casting. The first and second polymer layers are cast concurrently in one operation, creating a unified casing without separate layers that could delaminate. This merging approach maintains the extended service life benefit while eliminating the delamination problem inherent in multi-layer constructions.
Solution Approach 2:
The patent applies the first polymer layer and reinforcing structure before applying the second polymer layer in a coordinated casting process. The first layer is cast, then the reinforcing structure is embedded in it, and finally the second layer is cast over both. This preliminary sequencing ensures proper bonding and structural integration, preventing delamination while extending service life.
2Strength
If multiple polymer layers are applied sequentially, then the casing can be built up with reinforcing structures, but the manufacturing effort and production time increase
Solution Approach 1:
The patent merges the casting of multiple polymer layers into a single simultaneous operation. Instead of applying layers sequentially and allowing them to cure between operations, the first and second polymer layers are cast concurrently in one continuous motion. This combining approach maintains the strength benefits of multi-layer construction while dramatically reducing manufacturing time and effort.
Solution Approach 2:
The patent implements continuous casting motion where the first polymer layer is deposited, the reinforcing structure is embedded, and the second polymer layer is deposited all during one continuous casting operation. This eliminates interruptions and waiting periods between layer applications, maintaining productivity while achieving the required casing strength through proper layer sequencing.
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 method enhances the lifespan of the casing by improving adhesion between layers and simplifies the manufacturing process, reducing delamination and production time.
Implementation Method 1
The polymers that emerge from the two casting nozzles and, after crosslinking, form the two polymer layers of the jacket, are poured 'wet-on-wet' over one another during the inventive casting process. This term means that the first, radially inner polymer layer is not yet fully cross-linked—it is still 'sticky'—when the second, radially outer polymer layer is applied to it.
Implementation Method 2
The polymers that emerge from the two casting nozzles and, after crosslinking, form the two polymer layers of the jacket
Data Source
Figure 1~2
Figure 3a~3b
AI summary
The invention relates to a method for producing a multilayer casing for a spreading roller of a machine for producing and/or treating a fiber web. The invention additionally relates to a spreading roller with a casing produced according to such a method and to the use of a spreading roller casing produced according to such a method.