TAD Fabric Impermeable Strips for Paper Web Width Control
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Solution Overview
Problem
Existing papermaking machines face challenges with edge trimming and fabric degradation due to high energy consumption, resource inefficiency, and complex setup processes, particularly in determining the width of the paper web and protecting the drying fabric from premature degradation.
Innovation Solution
A papermaking machine section utilizing a fabric with laterally spaced impermeable strip portions that support the wet paper web for dewatering or drying, eliminating the need for deckle bands and providing a consistent permeable area for air flow, thus minimizing fabric exposure to hot air and reducing equipment complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If deckle bands are installed on the TAD cylinder to define drying area, then the width of paper web can be controlled, but the setup process becomes complex and time-consuming requiring trial-and-error to determine accurate positions
Solution Approach 1:
The invention removes the deckle bands from the TAD cylinder and instead incorporates impermeable strip portions directly into the TAD fabric. This extraction of the deckle band function from the cylinder and integration into the fabric simplifies the setup process while maintaining width control capability.
Solution Approach 2:
The TAD fabric with integrated impermeable strips serves its own function of defining the drying area width without requiring separate deckle bands. The fabric self-configures the drying zone through its inherent impermeable strip portions, eliminating the need for additional components and complex alignment procedures.
2Manufacturing precision
If high pressure water stream is used for edge trimming, then defined lateral edges are achieved, but significant amount of fresh water, piping, pump, and nozzle fixtures are required making the system costly and maintenance intensive
Solution Approach 1:
The invention extracts the edge trimming function from the separate water jet system and integrates it into the TAD fabric structure through impermeable strip portions. This eliminates the need for complex water delivery systems including high-pressure pumps, piping, and nozzle fixtures while achieving the same edge definition result.
Solution Approach 2:
The invention replaces the mechanical water jet edge trimming system with a passive fabric-based solution. The impermeable strips in the TAD fabric physically define the edges during the drying process itself, substituting an active mechanical cutting system with a passive structural definition approach.
3Productivity
If TAD fabric is exposed to hot air for drying, then drying efficiency is improved, but the fabric undergoes premature degradation
Solution Approach 1:
The TAD fabric is segmented into permeable areas for drying and impermeable strip portions for protection. This segmentation allows different regions of the fabric to serve different functions: the permeable areas expose the paper web to hot air for efficient drying, while the impermeable strips shield portions of the fabric from direct hot air exposure, reducing degradation.
Solution Approach 2:
The fabric has non-uniform properties with impermeable strip portions strategically positioned to provide localized protection. These impermeable regions create zones where hot air flow is blocked or redirected, providing local quality variation that protects vulnerable fabric areas while maintaining drying efficiency in the permeable zones.
4Reliability
If water spray or air knife systems are used to protect fabric from hot air, then fabric degradation is reduced, but equipment complexity and energy consumption increase
Solution Approach 1:
The invention removes the need for separate water spray or air knife protection systems by integrating the protective function directly into the TAD fabric structure. The impermeable strip portions inherently block hot air from degrading the fabric edges, eliminating complex auxiliary protection equipment.
Solution Approach 2:
The TAD fabric protects itself from hot air degradation through its built-in impermeable strip portions. Rather than requiring external protection systems, the fabric's own structure provides the necessary shielding, creating a self-protecting system that reduces complexity and energy consumption.
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
This solution enhances energy efficiency, reduces fabric degradation, simplifies setup and maintenance, and allows for flexible adjustment of paper web width without extensive testing, while effectively using heated air for drying and minimizing water intake by the drying fabric.
Implementation Method 1
each strip portion being substantially and consistently impermeable to air
Implementation Method 2
defining a web-carrying permeable portion (275) therebetween
Data Source
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AI summary
A papermaking machine section for dewatering or drying a wet paper web, comprising a papermaking endless fabric (100) configured to support a wet paper web (75) for dewatering, the fabric (100) comprising a permeable portion (275) and a pair of laterally spaced apart strip portions (250) extending along the fabric in the machine direction, each strip portion being impermeable to air and defining said permeable portion therebetween. According to the invention, the permeable portion is adapted such that the wet paper web supported thereby extends over the entire width thereof, whereby the permeable portion is configured to allow air directed thereat to flow therethrough, exclusively of the permeable strip portions, such that the wet paper web supported only by the permeable portion is dewatered, the width of the permeable portion between the impermeable strip portions thereby defining a corresponding width of the wet paper web being dewatered. At least one processing device is configured to provide a flow of air, said fabric being configured to interact with the at least one processing device.