Press Nip Web Separation Guide Roll Tension Control
Solution Overview
Problem
Conventional presses for producing fibrous materials face challenges in maintaining web tension and reliability after the press nip, leading to issues like web wrinkling and breaks, especially at high speeds, due to the high costs and maintenance requirements of suction felt guide rolls.
Innovation Solution
Incorporating a guide roll with a rotary drive immediately following the suction guide roll, equipped with a central drive journal, to maintain fabric tension over a larger distance and adjust the web travel trajectory, combined with a suction guide roll design featuring high vacuum zones and a pressure-absorbing surface, to ensure stable web travel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If suction felt guide rolls are used for web separation at high speeds, then web separation reliability is improved, but investment costs and maintenance costs increase significantly
Solution Approach 1:
The patent replaces expensive suction felt guide rolls with a cost-effective alternative consisting of a guide roll with fabric and a suction box. The fabric can be easily replaced when worn, avoiding the high investment costs and maintenance expenses of conventional suction felt guide rolls while maintaining web separation reliability at high speeds
Solution Approach 2:
The patent creates a functional copy of the suction felt guide roll system using different components - a guide roll covered with fabric instead of a solid suction felt roll. This copy achieves the same web separation function through a combination of mechanical guidance and suction, but at significantly lower cost
2Reliability
If suction felt guide rolls are used, then web separation is reliable, but felt tension drops drastically after the press nip causing web travel problems
Solution Approach 1:
The patent separates the functions of web separation and tension maintenance into distinct components: the suction box handles web separation while the guide roll with fabric maintains felt tension. This segmentation prevents the tension drop problem that occurs when suction and guidance are combined in a single suction felt guide roll
Solution Approach 2:
The guide roll covered with fabric acts as an intermediary between the press nip and the web separation point. It maintains felt tension stability while allowing the suction box to perform web separation, preventing the tension drops that cause web travel malfunctions
3Device complexity
If a rotary drive is provided with suction on one drive side, then the system is compact, but suction must be relocated to the operator side which increases costs
Solution Approach 1:
The patent merges the rotary drive and suction system on the same drive side, eliminating the need for expensive suction relocation to the operator side. The guide roll with fabric and the suction box work together on the drive side, simplifying the overall system configuration and reducing manufacturing costs
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 configuration enhances the reliability and stability of web travel after the press nip, reducing manufacturing costs and minimizing web breaks, while maintaining high web speeds and handling various basis weights of fibrous materials.
Implementation Method 1
One guide roll of a plurality of guide rolls that is arranged at the separation point is a vacuum equipped guide roll of the lower felt and among other things serves to hold the fibrous web on the bottom felt at the separation point
Data Source
AI summary
The invention relates to a press for a machine for producing a fibrous material web, including at least one press nip formed between a press roller and a counter press roller of the press for guiding through the fibrous material web in a dehydrating manner, and two band shaped covers, which are each guided by multiple guide rollers in continuous circulation, so as to run together through the press nip, so that the fibrous material web is guided through sandwiched between said covers, and then separated again at a separation point, in order to continue guiding the fibrous material web on the one cover and separate it from the other cover. One guide roller of the guide rollers arranged at the separation point is a suctioned guide roller of the one cover, to hold the fibrous material web on the one cover at the separation position.