Water-Absorbing Papermaking Felt for Stable Dewatering
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Solution Overview
Problem
Conventional papermaking felts face issues with shortening the initial warming-up period while maintaining water squeezing capability due to excessive compaction, leading to reduced compressibility and water permeability, and fiber loss under repeated pressure.
Innovation Solution
Incorporating a water-absorbing resin with a coefficient of water absorption between 1.05 and 10 into the batt layer of the felt, which maintains free space volume and compressibility, ensuring effective water drainage and elasticity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the felt is compacted to reduce free space volume, then water squeezing capability is improved, but compressibility and water permeability are reduced
Solution Approach 1:
The patent applies parameter changes by controlling the free space volume within a specific range (30-70% of total volume) rather than maximizing compaction. This optimized parameter range maintains sufficient compressibility while achieving effective water squeezing capability during the warming-up period and constant speed operation.
Solution Approach 2:
The patent uses composite materials by combining fibers with different properties (cellulose fibers, synthetic fibers, and staple fibers) in the batt layer. This composite structure provides both the compressibility needed for initial water removal and the structural integrity for sustained operation, resolving the contradiction between initial performance and durability.
2Reliability
If the felt is compacted to reduce free space volume, then water squeezing capability is improved, but water permeability is reduced
Solution Approach 1:
The patent optimizes the free space volume parameter to a specific range (30-70%) that balances water squeezing capability with water permeability. This parameter control ensures that water can permeate through the felt while still achieving effective dewatering during press operation.
Solution Approach 2:
The patent applies local quality by creating different regions within the felt structure - the batt layer provides compressed regions for water squeezing, while the base material and fiber arrangement maintain open channels for water permeability. This spatial differentiation resolves the contradiction between squeezing efficiency and drainage capability.
3Productivity
If the initial warming-up period is shortened by compaction, then productivity is improved, but the operational period is reduced due to fiber loss
Solution Approach 1:
The patent uses composite materials combining different fiber types (cellulose, synthetic, and staple fibers) with complementary properties. The cellulose and synthetic fibers provide structural stability to prevent fiber loss, while the overall structure achieves rapid warming-up, thus extending the operational period without sacrificing productivity.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating a cross-section ratio of 0.4 or more, which provides structural cushioning that prevents fiber loss during operation. This pre-designed structural buffer allows the felt to achieve short warming-up periods while maintaining durability throughout the operational period.
4Reliability
If pressure is applied to make the felt thinner, then free space volume is reduced for better water squeezing, but compressibility is lost
Solution Approach 1:
The patent applies parameter changes by controlling the thickness and free space volume within optimized ranges rather than maximizing compaction. This parameter optimization maintains the felt's ability to compress under pressure while preserving sufficient compressibility for sustained water squeezing capability throughout the operational period.
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 water-absorbing resin maintains water drainage capability and elasticity, shortening the initial warming-up period and extending the operational period by maintaining suitable water permeability and compressibility.
Implementation Method 1
a water-absorbing resin with a coefficient of water absorption between 1.05 and 10 is included in the batt layer
Implementation Method 2
pressure is applied on a wet paper web, which is transported by a felt traveling at substantially a same speed and in the same direction, together with the felt by one roll and the other roll
Data Source
Figure 1~2
AI summary
The object of the invention is to provide a papermaking felt, wherein the basic functions are well balanced, which does not have any wet paper web transfer deficiencies due to meandering, or the like, wherein free space of a felt, in which the effect of the press pressure and the hydraulic pressure is scarcely conveyed to the wet paper web, is set to the suitable amount for the initial warming-up period from the start so that the initial warming-up period is shortened, and wherein water squeezing does not deteriorate due to premature decline of water permeability and due to the inability to maintain compressibility by excessive compaction and accumulation of dirt. The object is achieved by a papermaking felt made from a base material 1 and batt layers 2, 3 provided at least on the wet paper web carrying-side layer; wherein a water-absorbing resin 4 is included in the batt layer 2 of the felt. The base material 1 may either have an endless shape, or an open-ended felt may be connected into an endless shape in a papermaking machine. The water-absorbing resin in the felt may either stay in the front batt layer 2 (Fig. 1), or it may also reach the base material 1 or the rear batt layer 3 (Fig.2).