Papermaking Felt With Nonwoven Barrier for Rewetting Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The rewetting phenomenon in papermaking processes leads to increased water content in the wet paper web, directly impacting energy consumption in the drying stage, necessitating a solution to suppress this phenomenon and reduce moisture content.
Innovation Solution
A papermaking felt configuration featuring a batt layer and nonwoven fabric with specific penetration resistance, hydrophilic fibers, and controlled moisture regain, ensuring the nonwoven fabric acts as a barrier to prevent moisture migration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a conventional papermaking felt is used in the press part, then the wet paper web can be processed, but the rewetting phenomenon occurs causing increased water content at the outlet
Solution Approach 1:
The papermaking felt is divided into multiple functional layers: a substrate layer for structural support, a first batt layer for water absorption, and a second batt layer for preventing rewetting. This segmentation allows each layer to perform its specific function optimally, preventing water from returning to the wet paper web while maintaining processing capability.
Solution Approach 2:
The invention uses a composite structure combining different materials with complementary properties: the substrate provides mechanical strength, the first batt layer (made of hydrophilic fibers) absorbs water, and the second batt layer (made of hydrophobic fibers) prevents rewetting. This composite material approach solves the contradiction by integrating multiple functions into a single felt structure.
2Productivity
If the pressure is released rapidly in the press part, then the papermaking felt and wet paper web expand rapidly, but negative pressure is generated causing rewetting
Solution Approach 1:
The second batt layer is pre-configured with hydrophobic fibers that actively resist water absorption before negative pressure can cause rewetting. This preliminary protective action counteracts the harmful effect of rapid pressure release and negative pressure generation, allowing high productivity while preventing the rewetting phenomenon.
Solution Approach 2:
The second batt layer acts as an intermediary barrier between the wet paper web and the external environment. During rapid pressure release, this intermediate layer prevents water from being drawn back into the wet paper web through capillary action, thereby eliminating the harmful rewetting effect while maintaining pressing efficiency.
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 configuration effectively suppresses rewetting, reducing the moisture content of the wet paper web and optimizing energy efficiency by minimizing water retention post-pressing.
Implementation Method 1
a capillary phenomenon is also applied because the wet paper web is made of fine fibers, resulting in so-called rewetting phenomenon
Implementation Method 2
the papermaking felt continuously absorbs water or the water passes through the felt to be drained to the outside
Data Source
AI summary
Provided is a papermaking felt having a wet paper web carrying surface for carrying a wet paper web, comprising a substrate, a batt layer placed on the wet paper web carrying surface side of the substrate and comprising a short fiber, and a nonwoven fabric placed adjacent to the batt layer on the wet paper web carrying surface side of the substrate, wherein the nonwoven fabric has a penetration resistance of 2.0 N/(100 g/m2×number of needles) or less per one needle when the basis weight of the fabric is 100 g/m2.