Dual-Layer Process Roll Cover for Extended Nip Time
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The production of tissue or towel paper faces challenges with decreased nip time leading to product quality degradation, and existing solutions involving additional rollers are costly and complex, requiring durable rollers that can withstand the papermaking process.
Innovation Solution
A process roller design featuring an inner and outer ring structure, where the outer ring is harder than the inner ring, both made of rubber, to increase nip time and durability, allowing for improved product quality and longer equipment life.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the nip time is decreased to increase production speed, then productivity is improved, but product quality deteriorates
Solution Approach 1:
The patent changes the physical parameters of the roller by using a multi-layer construction with different hardness values. The harder outer layer (50-70 Shore A) maintains roller durability and shape stability at high speeds, while the softer inner layer (20-40 Shore A) provides extended nip time for quality bonding, resolving the contradiction between production speed and product quality
Solution Approach 2:
The roller employs a composite structure combining rubber layers of different hardness values. This composite design allows the roller to simultaneously provide the structural integrity needed for high-speed operation and the compliance needed for extended nip time, thereby maintaining both productivity and manufacturing precision
2Manufacturing precision
If additional rollers are used to increase nip time, then product quality is improved, but device complexity and capital cost increase
Solution Approach 1:
Instead of adding more rollers to the system, the patent changes the parameters of the existing roller by implementing a multi-layer construction. This allows a single roller to achieve the nip time extension that would otherwise require additional rollers, thereby improving product quality without increasing device complexity
3Reliability
If the roller operates for an adequate period to ensure durability, then reliability is improved, but the roller must withstand harsh papermaking conditions which accelerates wear
Solution Approach 1:
The roller uses a composite structure where the harder outer layer (50-70 Shore A) acts as a protective barrier against the harsh papermaking environment, while the softer inner layer (20-40 Shore A) maintains the necessary compliance for quality operation. This composite design enhances reliability by protecting the roller against wear, chemical exposure, and mechanical stress
Solution Approach 2:
The patent applies local quality by giving different parts of the roller (different layers) different hardness properties. The outer layer has higher hardness to resist wear and environmental damage, while the inner layer has lower hardness to provide compliance, creating a gradient that optimizes both durability and performance under harsh conditions
Data Source
AI summary
A process roller is provided including an inner core and a roller cover structure adapted to be mounted on the inner core for rotation with the inner core, the roller cover structure defining an outer surface adapted to mate with at least one of a belt or a mating roller such that a nip receives at least one of a wet web or a fibrous structure, in which the roller cover structure includes an inner ring positioned about the inner core and an outer ring positioned about the outer ring, where the outer ring has a higher hardness than the inner ring and the inner ring and outer ring are formed from a rubber. Also disclosed is an apparatus that includes the corresponding process roller and a method for joining a first fibrous structure to a second fibrous structure using the corresponding apparatus.