Revolving Rod Soft Polymer Coating for Paper Web Wear
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Solution Overview
Problem
Traditional revolving rods used for coating applications on paper or paperboard webs suffer from excessive wear, leading to high replacement costs and quality defects such as 'puttying' due to their hard and inflexible surfaces, which result in patchy coating layers.
Innovation Solution
A revolving rod with a soft, wear-resistant surface coating having a modulus of elasticity less than 15 N/mm², preferably between 0.1 and 10 N/mm², made from organic polymers like polyurethanes, which is more compliant with the web surface, reducing wear and improving coating quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rod face is made hard and wear-resistant through hardening or surface coating, then the wear resistance is improved, but the coating quality deteriorates due to puttying effect and patchiness
Solution Approach 1:
The invention changes the material parameter of the rod face from hard materials (chromium, ceramic) to soft materials (polymer materials with specific elasticity modulus). This parameter change resolves the contradiction by allowing the soft rod face to conform to web surface irregularities, eliminating the puttying effect while maintaining wear resistance through the use of specifically selected polymer materials that resist wear despite their softness.
Solution Approach 2:
The invention uses composite material structure consisting of a rod body with integrated soft polymer rod face. The polymer material combines softness for conforming to web surface with wear-resistant properties, creating a composite solution that simultaneously achieves both coating quality and durability without requiring separate hard coating layers.
2Manufacturing precision
If the rod face is made soft to improve coating quality, then the puttying effect is reduced, but the wear resistance deteriorates
Solution Approach 1:
The invention changes the material parameter from conventional hard materials to soft polymer materials with specifically controlled elasticity modulus. This parameter change enables the rod face to be soft enough to conform to web surface irregularities and eliminate puttying, while the selected polymer materials inherently provide sufficient wear resistance for continuous operation.
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 soft surface coating reduces wear and 'puttying' effects, resulting in improved coating quality and extended rod lifespan, allowing for better fiber coverage and reduced web break frequency, while also enabling novel coating concepts.
Implementation Method 1
The soft surface coating material will more easily will let particles pass, which particles may be present in the paper or paperboard web, or in the coating mix. Directly after the passage of a particle, the surface coating material will then return to its initial position.
Implementation Method 2
Directly after the passage of a particle, the surface coating material will then return to its initial position.
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
A dosing device for the application of a coating mix (6) onto a running web, in particular a paper or paperboard web (1), which device comprises a rod (8) that is supported revolvingly over its entire length in a rod cradle (12), and a pressing device (13) acting on the rod cradle and producing a pressure of the rod onto the web (1) and onto the holding-on device (2, 17, 15) of the web, the rod (8) being provided with a wear resistant surface coating (15) with a hardness of about 10 to about 100 according to Shore A. The invention also relates to methods of using said rod, and to said revolving rod.