Flat Reinforcing Threads in Polymer Press Jackets

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Solution Overview

Problem

Press jackets in shoe presses used for treating fibrous webs tend to fail prematurely due to local overloading, leading to increased downtime and maintenance costs, as they are prone to mechanical stress and damage from foreign objects passing through the nip.

Innovation Solution

The use of flat reinforcing threads embedded in a polymer layer, where the reinforcing threads are designed to have a flat outer contour and are made from single fibers or fiber bundles, reducing their tendency to separate from the polymer layer and enhancing the press jacket's ability to withstand local overloads.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional reinforcing threads (round or twisted fiber bundles) are used in the press sleeve, then the press sleeve can be manufactured with standard materials and processes, but the press sleeve tends to fail prematurely due to local overloading and foreign objects passing through the nip

Engineering Contradiction:
Improveservice life of press sleeveVSAvoidresistance to local overload
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent changes the geometric parameter of the reinforcing thread from round/twisted to flat cross-section. This parameter change allows the thread to better distribute local loads across its width and prevents concentration of stress at single points, thereby increasing resistance to local overload and foreign object damage while maintaining manufacturability

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite structure by embedding flat reinforcing threads within a polymer matrix layer. The flat threads provide tensile strength and dimensional stability, while the polymer matrix provides flexibility and load distribution. This composite approach enables the press sleeve to withstand both uniform pressure and localized overloads without premature failure

Inventive Principle:
Principle #40Composite materials

2Stability of the object's composition

If the press sleeve is made sufficiently rigid to withstand press load, then it maintains structural stability, but it becomes more prone to damage from alternating bending loads during running in and out

Engineering Contradiction:
Improvestructural stability of press sleeveVSAvoidresistance to alternating bending loads
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The patent employs a flexible polymer matrix that encases the reinforcing threads, creating a shell structure that can accommodate bending deformations. The polymer layer acts as a flexible membrane that absorbs and distributes bending stresses, preventing crack initiation and propagation while maintaining the overall structural stability provided by the embedded flat threads

Inventive Principle:
Principle #30Flexible shells and thin films

3Ease of operation

If the press sleeve is made sufficiently flexible to be guided around the shoe, then it can navigate the press nip, but it deforms or compresses excessively under press load

Engineering Contradiction:
Improveguidability around shoeVSAvoidresistance to compression in nip
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The composite construction with flat reinforcing threads embedded in a flexible polymer matrix creates a material that exhibits both flexibility and compressive strength. The polymer matrix provides the flexibility needed for guidability, while the flat threads embedded within it provide structural reinforcement that prevents excessive compression and deformation under press load

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP3830335B1Press cover, use thereof, and press roll and shoe press
Publication Date: 2024.10.23 VOITH PATENT GMBH
  • EP3830335B1 patent drawingFigure 1~2b
  • EP3830335B1 patent drawingFigure 3~4b

AI summary

The invention relates to a press cover comprising at least one polymer layer, in which a reinforcing structure is embedded, wherein the reinforcing structure comprises at least one reinforcing thread, wherein the at least one reinforcing thread is designed as a flat thread.