Step Air Foil Web Stabilizer for Wrinkle Removal
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Solution Overview
Problem
Conventional air foils for web flotation and drying are ineffective in maintaining stability and preventing wrinkles in lightweight webs under medium to high tensions, as they rely on web flatness to trap air and fail to maintain velocity, leading to machine direction corrugations and web damage.
Innovation Solution
A step air foil web stabilizer with a primary and secondary air slot design that discharges air parallel to the web, maintaining constant air velocity and increasing the air cushion for enhanced support, independent of web flatness, to double the draw-down force and flatten machine direction wrinkles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If conventional air foils discharge air at 45° to the web, then the web is pushed up and air is trapped between the air foil face and the web, but machine direction corrugations form in the web under medium to high tensions, allowing air to escape and reducing velocity
Solution Approach 1:
The air foil is segmented into multiple discharge slots (first, second, and third slots) positioned at different locations and angles. This segmentation allows each slot to perform a specific function: the first slot at a first angle creates initial air cushion, the second slot at a second angle enhances the air cushion, and the third slot at a third angle provides additional support, collectively maintaining web stability and preventing corrugation formation under various tension conditions.
Solution Approach 2:
Different portions of the air foil have different discharge slot configurations with specific angles and positions tailored to local requirements. The discharge slots are arranged to create varying air pressure distributions across the web width, providing localized air cushioning where needed most to prevent corrugations while maintaining overall web stability and flotation effectiveness.
2Length of stationary object
If single slot air bars are used for flotation, then flotation clearance can be reduced to about 2.3 mm, but heat transfer and flotation stability dramatically decrease as clearance is increased
Solution Approach 1:
The flotation system is divided into multiple discharge slots positioned at different heights and angles relative to the web. This segmentation creates multiple air cushions that collectively maintain stable flotation over a wider clearance range. The distributed slot configuration ensures that even as clearance increases, each slot continues to provide effective air support, preventing the dramatic stability loss seen in single-slot designs.
Solution Approach 2:
The invention transitions from a single-slot configuration to a multi-slot arrangement that utilizes vertical and angular dimensions. By positioning slots at different heights (first, second, third slots) and angles, the system creates a three-dimensional air cushion structure that maintains flotation stability across varying clearances, effectively adding dimensional complexity to overcome the clearance-stability tradeoff.
3Device complexity
If conventional air foils rely on web flatness to trap air, then simple design is maintained, but velocity is not maintained and draw-down force is insufficient to flatten machine direction wrinkles
Solution Approach 1:
The air foil incorporates multiple discharge slots (first, second, third slots) positioned at different angles and locations. This segmentation creates multiple air jets that collectively generate sufficient draw-down force to flatten machine direction wrinkles while maintaining web control. The distributed slot configuration provides cumulative force that overcomes the limitations of single-slot designs without requiring complex additional mechanisms.
Solution Approach 2:
The invention utilizes pneumatic principles by discharging air through multiple slots at specific angles to create air jets that exert force on the web. The angled discharge (first angle, second angle, third angle) creates aerodynamic forces that generate the necessary draw-down force to flatten wrinkles and control the web, leveraging fluid dynamics to achieve the required force without mechanical complexity.
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
The solution provides stable one-sided flotation and enhanced drying capabilities, removing wrinkles and ensuring a smooth transition into dryer zones without web flutter or marking, with a working window of operation twice that of conventional designs, achieving a glass-like appearance and increased flotation height for higher tensioned webs.
Implementation Method 1
Air discharged from the primary slot is gathered into the air stream of the secondary slot and creates an increased air cushion to provide greater support to the moving web
Implementation Method 2
Air discharged from the primary slot is gathered into the air stream of the secondary slot and creates an increased air cushion to provide greater support to the moving web
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Web stabilizer particularly for one-sided flotation of a running web. The device includes two discharge slots which allow for increased draw down force, which flattens machine direction wrinkles in a floating web. There is a primary discharge slot and a second discharge slot spaced from and stepped down from the primary discharge slot, a first web support surface between the primary discharge slot and the secondary discharge slot, and a second web support surface downstream of the secondary discharge slot in the direction of web travel. An integral blower provides a supply of air that is uniformly distributed to the primary and secondary slots. Air discharged from the primary slot is gathered into the air stream of the secondary slot and creates an increased air cushion to provide greater support to the web and thereby remove machine direction web wrinkles caused by higher tension in light weight webs.