Extended Nip Roll Movable Support Elements
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Solution Overview
Problem
Extended nip rolls face challenges in maintaining the shape of tubular flexible jackets, particularly when processing fibrous webs, as they can sag or flutter due to varying operating conditions and pressures, which can lead to inconsistent performance.
Innovation Solution
The extended nip roll design incorporates a support beam with movable support elements that can adjust circumferentially and radially along the tubular flexible jacket, utilizing actuators and guides to ensure consistent support and prevent sagging, allowing for dynamic adjustment to changing conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid metal shoe is used as the press body, then structural strength and shape stability are improved, but adaptability to different counter element shapes is worsened
Solution Approach 1:
The press body is made flexible through a tubular flexible jacket that can dynamically adapt its shape to different counter elements while maintaining structural integrity through internal support ledges and pressurized air, resolving the contradiction between rigidity and adaptability
Solution Approach 2:
A tubular flexible jacket is used as the press body instead of a rigid metal shoe, allowing the press body to conform to different counter element shapes while maintaining sufficient structural strength through the jacket design and internal support mechanisms
2Stability of the object's composition
If pressurized air is used to prevent the tubular flexible jacket from sagging, then shape stability is improved, but device complexity and energy consumption are worsened
Solution Approach 1:
The support system is segmented into discrete support ledges positioned at specific locations along the tubular flexible jacket, providing localized support where needed rather than requiring continuous pressurization, thereby reducing system complexity
Solution Approach 2:
The tubular flexible jacket is designed to maintain its shape through its own structural properties and the mechanical support of internal ledges, reducing or eliminating the need for external pressurized air systems
3Stability of the object's composition
If fixed support ledges are used to support the tubular flexible jacket, then shape stability is improved, but adaptability to varying operating conditions is worsened
Solution Approach 1:
The support ledges are made movable rather than fixed, allowing them to adjust their position and provide optimal support under varying operating conditions such as different web tensions, speeds, and moisture contents, thereby resolving the contradiction between stability and adaptability
Data Source
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AI summary
The invention relates to an extended nip roll 1 for use in a nip N through which a fibrous web W is to be passed. The roll has two axial ends 3, 4 and comprises a support beam 5 having an axial extension between the axial ends 3, 4 of the extended nip roll and a press body 6 with an axial extension and which press body 6 is substantially parallel with the support beam 5 as well as means 7 supported by the support beam 5 for causing the press body to move or expand radially outwards towards a counter roll 2 to form a nip N. The inventive roll also comprises a tubular flexible jacket 8 with two axial ends 12, 13, the tubular flexible jacket 8 forming a loop around the press body 6 and the support beam 5. At each end of the extended nip roll 1, there is an end wall 9, 10 which is rotatably journalled to allow each end wall 9, 10 to rotate about the support beam 5. Each end wall 9, 10 being attached to an axial end 12, 13 of the tubular flexible jacket 8 such that the end walls 9, 10 and the tubular flexible jacket 8 form together an enclosed space 14. On the support beam 5, there is at least one support element 15 for the tubular flexible jacket 8 which support element 15 is arranged to support a part of the tubular flexible jacket 8 at a location spaced away from the press body 6. According to the invention, the at least one support element 15 is arranged to be movable in a circumferential direction such that it can be moved to different positions along the circumference of the tubular flexible jacket 8.