Creping Belt Offset Openings for Web Transfer
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The transfer of a nascent web onto a creping structure in papermaking processes is challenging due to its high moisture content, making it difficult to achieve consistent web transfer and desired properties in the paper products.
Innovation Solution
A creping belt with offset openings in both the machine direction (MD) and cross-machine direction (CD) is used, featuring a multilayer structure with a polymeric top layer and a woven or extruded polymeric bottom layer, allowing for improved web transfer and fiber orientation, and preventing fiber pull-through.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If openings in the creping belt are aligned in the machine direction and cross-machine direction, then the belt structure is simple and easy to manufacture, but the web transfer consistency deteriorates due to high moisture content making the nascent web unstable
Solution Approach 1:
The patent applies asymmetry by offsetting the openings in the creping belt from a regular aligned grid pattern. The openings are positioned at offset positions in both the machine direction and cross-machine direction, creating an asymmetric distribution that improves web transfer consistency by better accommodating the unstable, high-moisture nascent web during the transfer operation.
2Manufacturing precision
If openings are offset from lines in both MD and CD directions, then web transfer consistency improves, but the belt manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by creating zones of different opening densities and positions throughout the belt surface. The offset opening pattern creates local variations in the belt structure that are optimized for web transfer, while maintaining an overall regular pattern that allows for manufacturable construction using standard belt making techniques.
3Reliability
If a multilayer belt structure is used with polymeric top layer and woven bottom layer, then fiber pull-through is prevented and web transfer is improved, but the belt manufacturing process becomes more complex
Solution Approach 1:
The patent applies composite materials by combining a polymeric top layer with a woven or extruded polymeric bottom layer to form a multilayer creping belt. This composite structure provides both the opening pattern needed for web transfer and the structural integrity to prevent fiber pull-through, while utilizing compatible polymeric materials that can be bonded together in a manufacturable process.
Data Source
AI summary
A belt for creping a web in a papermaking process. The belt includes a surface onto which the web is transferred during the papermaking process. A plurality of openings extend through the surface, with the openings being arranged in lines that are offset from lines in the machine direction (MD) and cross-machine direction (CD) of the belt. Paper products, such as absorbent sheets, made from the belt have hollow dome regions and connecting regions between the domes, with the domes being arranged in lines that are offset from lines in the MD and CD of the paper products.