Hydrostatic Roll Nip Regulation for Film Calendaring
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Solution Overview
Problem
Conventional roll arrangements struggle to maintain a constant roll nip thickness, especially when processing thin, high-density materials or those with varying thicknesses, leading to potential mechanical overstress and thickness deviations during calendaring processes.
Innovation Solution
A roll arrangement with interconnected clamping latches and actuating elements, where bearing jewels are maintained in a defined rest position by a controller, allowing for precise adjustment of the roll nip to accommodate varying material thicknesses and densities, using hydraulic or pneumatic actuation to maintain the required densification and prevent edge forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional mechanical elements (bearings, bearing seats, rolls, roll journals) are pre-tensioned to maintain roll nip, then roll nip stability is improved, but mechanical overstress occurs when material web falls below critical value causing elements to fall on each other
Solution Approach 1:
The patent replaces the conventional pre-tensioned mechanical support system with a hydrostatic bearing system that uses fluid pressure to support the rolls. This substitution eliminates the risk of mechanical elements falling on each other and causing overstress, while maintaining roll nip stability through controlled fluid pressure adjustment.
Solution Approach 2:
The patent introduces a hydrostatic bearing system as an intermediary between the rolls and their supports. This intermediary uses fluid pressure to prevent direct contact and potential damage between mechanical elements, while still maintaining the required roll nip stability for thin material processing.
2Manufacturing precision
If wedge is used to adjust roll nip to compensate for load rise, then roll nip thickness is improved, but regulation speed is slow and thickness deviations occur
Solution Approach 1:
The patent replaces the slow mechanical wedge adjustment system with a hydrostatic bearing system controlled by fluid pressure. This allows for much faster regulation of roll nip thickness while maintaining high precision, as fluid pressure can be adjusted rapidly and precisely compared to mechanical wedge movement.
Solution Approach 2:
The patent uses hydrostatic bearings with fluid pressure control to achieve fast and precise roll nip regulation. The hydraulic system allows for rapid adjustment of bearing positions and roll gap, enabling the system to respond quickly to load changes while maintaining thickness precision.
3Stability of the object's composition
If bearing blocks are arranged in bearing jewels on roll journals, then roll support stability is improved, but complexity of bearing arrangement increases
Solution Approach 1:
The patent combines the bearing block and bearing jewel functions into an integrated hydrostatic bearing assembly. This merging reduces the number of separate components and simplifies the overall bearing arrangement while maintaining or improving roll support stability through the hydrostatic fluid pressure system.
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 enables precise control of the roll nip, preventing mechanical overstress and ensuring consistent thickness across the material web, even with intermittently coated films, by maintaining the roll nip's position and reducing vibrational responses and edge forces, thus enhancing the accuracy and longevity of the calendaring process.
Implementation Method 1
using hydraulic or pneumatic actuation to maintain the required densification
Implementation Method 2
Hydrostatic thrust bearings for contact-free support of cylinder section of idle rolls by means of fluid pressure
Implementation Method 3
Hydrostatic thrust bearings for contact-free support of cylinder section of idle rolls by means of fluid pressure
Data Source
AI summary
A compact roll arrangement has a device and method for regulating the roll nip so that intermittently coated films may be calendared precisely. A bearing block is arranged in a bearing jewel, and first lever arms of the clamping latch of the upper roll and the lower roll are connected rigidly to one another. Bearing jewels which lie opposite to one another, of the upper roll and the lower roll are connected to one another via a second actuating element. A controller acts on first and second actuating elements, so that the first actuating elements are moved to adjust the roll nip according to a predetermined thrust and a predetermined linear load, and the second actuating elements are moved to maintain the bearing jewels in a relative rest position which is defined by specified densification of a material web passing the roll nip.