Press Roll Cover With Adjustable Drainage Openings
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Solution Overview
Problem
Existing pressing devices for fibrous webs, such as paper or cardboard, face challenges in maintaining optimal dewatering performance due to natural wear and tear, filler accumulation, and the inability to adjust drainage volumes to accommodate different grammages or types of webs, leading to reduced efficiency.
Innovation Solution
The drainage volume of the pressing device is made variably adjustable by altering the cavity volumes of the press felt and roller cover, allowing for reduction or increase based on operational needs, using methods like cross-sectional constrictions in drainage openings and removable thread-like inserts in the roller cover.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the drainage volume of the pressing device is increased to improve dewatering performance, then the dewatering capacity is improved, but the device complexity increases due to the need for adjustment mechanisms
Solution Approach 1:
The press roll cover is designed with adjustable drainage openings that can vary the drainage volume dynamically. The cover includes a body with drainage openings and an adjustable element that can move to change the opening size, allowing the dewatering capacity to be adapted to different operational requirements while maintaining a relatively simple overall structure
Solution Approach 2:
The invention changes the physical parameter of the drainage opening size by providing an adjustable element that can modify the cross-sectional area of the drainage openings. This allows the drainage volume to be varied between a first value and a second value, enabling optimization of dewatering performance for different web types and grammages without complex system redesign
2Productivity
If the void volume of press felt and press roll is increased to maintain dewatering performance, then the dewatering performance is maintained, but the manufacturing cost increases
Solution Approach 1:
Instead of manufacturing press rolls with permanently large void volumes, the invention provides a dynamically adjustable cover that can modify the effective drainage volume during operation. This allows the use of more cost-effective manufacturing processes for the press roll body while achieving optimal dewatering performance through the adjustable cover component
Solution Approach 2:
The press roll is segmented into a body and a separate adjustable cover component. The cover can be removed and replaced or adjusted independently, allowing for simpler manufacturing of the main roll body and easier maintenance or modification of the drainage characteristics without replacing the entire expensive press roll assembly
3Adaptability or versatility
If the drainage openings are constricted to reduce dewatering capacity, then the adaptability to different web types is improved, but the dewatering performance decreases
Solution Approach 1:
The adjustable element in the press roll cover enables dynamic constriction or expansion of the drainage openings. This allows the operator to adapt the dewatering capacity to match different web types and grammages while maintaining optimal performance for each specific application, rather than being fixed at a single drainage capacity
Solution Approach 2:
The invention changes the drainage opening parameters (cross-sectional area, volume) to match the specific requirements of different web types. By providing controlled constriction of the drainage openings, the system can optimize the balance between adaptability and dewatering performance for each production run
Data Source
Figure 1
Figure 2~4
AI summary
The invention relates to a method for the variable setting of the dewatering performance of a pressing device for a machine for producing a fibrous web, such as a paper, tissue or cardboard web, wherein the dewatering performance of the pressing device is set in a variable manner by way of variation of the (in particular, currently) available dewatering volume of the pressing device. Furthermore, the invention relates to a roll cover for a pressing device, to a pressing device of this kind, and to a machine for producing a fibrous web, such as a paper, tissue or cardboard web, comprising a pressing device of this type.