Web Processing Roll Directional Vacuum Ports
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Solution Overview
Problem
Web processing rolls face significant pressure drop issues in axial vacuum passages due to friction and flow blockage, leading to reduced vacuum pressure towards the center of the machine, especially as rolls become wider and faster, which existing designs struggle to mitigate without increasing passage size.
Innovation Solution
The implementation of vacuum holes with aligned flow paths, varying cross-sectional shapes, and angled orientations to direct air flow axially with the vacuum passage, reducing interference and pressure drop, and using removable inserts for complex shapes that can be 3D-printed or machined, to enhance vacuum distribution and maintainance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the cross-section of vacuum passages is increased to reduce pressure drop, then pressure drop is reduced, but the roll body does not have enough space to make the axial vacuum passages large enough
Solution Approach 1:
The patent implements a tube-in-tube design where an inner tube is nested within an outer tube to form the vacuum passage. This nested structure allows the vacuum passage to occupy space efficiently within the roll body, maximizing the effective cross-sectional area for vacuum flow without increasing the overall roll dimensions. The inner tube can be positioned concentrically or eccentrically within the outer tube, creating a annular or composite passage that optimizes space utilization while maintaining sufficient flow area to reduce pressure drop.
2Productivity
If the vacuum passage is made larger to reduce pressure drop, then pressure drop is reduced, but the roll body space is insufficient
Solution Approach 1:
The tube-in-tube configuration enables the vacuum passage to achieve a larger effective cross-sectional area for air flow by nesting the inner tube within the outer tube. This allows the passage to utilize the annular space between the two tubes, effectively increasing the flow area without proportionally increasing the roll body volume. The nested design optimizes the ratio of passage area to roll volume, enabling higher air flow capacity within constrained spatial boundaries.
Solution Approach 2:
The patent transitions from a simple axial vacuum passage to a three-dimensional tube-in-tube structure. By adding the radial dimension with concentric or eccentric tube arrangement, the design creates a multi-dimensional flow path that increases the effective cross-sectional area for vacuum flow. This dimensional approach allows air to flow through both the inner tube and the annular space between tubes, effectively multiplying the flow capacity without linearly increasing the roll body dimensions.
3Volume of stationary object
If axial vacuum passages are made small, then roll body space is efficient, but pressure drop is significant
Solution Approach 1:
The nested tube structure creates an efficient use of roll body space while maintaining a large effective vacuum passage area. The inner tube is positioned within the outer tube, utilizing the annular space to create a composite passage that maximizes flow area within the available radial space. This nested arrangement reduces pressure drop by providing a larger flow area without wasting roll body volume, as the structure efficiently packs the passage within the roll's dimensional constraints.
Solution Approach 2:
The patent changes the geometric parameters of the vacuum passage by implementing a tube-in-tube configuration with specific dimensional relationships. The inner tube diameter, outer tube diameter, and their relative positioning (concentric or eccentric) are optimized to maximize the annular flow area while minimizing the overall space occupied. By adjusting these parameters, the design achieves a balance between compact space utilization and sufficient flow area to minimize pressure drop losses.
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 significantly reduces pressure drop by aligning air flow with the vacuum passage, maintaining higher vacuum pressure across the roll, even with wider rolls, and allows for efficient handling and folding of web materials with improved vacuum performance.
Implementation Method 1
Pressure drop down the length of the axial vacuum passages is a significant problem as folders get wider and faster. The pressure drop manifests as reduced vacuum toward the center of the machine. The pressure drop is caused by axial vacuum passages too small for the air flow through them.
Implementation Method 2
The pressure drop down the length of an axial vacuum passage has at least two components. One component is friction between the flowing air and the passage wall.
Implementation Method 3
The other component is flow blockage caused by jets of air entering the vacuum passage from the holes in the roll face.
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A web processing roll (100, 200, 300, 400) for handling a web of material using vacuum is provided. The web processing roll includes a roll body (102, 502, 602). The roll body defines an outer periphery (104, 204, 304, 404, 504) against which the web of material is held. The roll body defines a vacuum passage (116, 120, 216, 416, 516, 616). At least one first vacuum hole (106, 206, 306, 406, 506, 606) fluidly connects to the vacuum passage provides vacuum proximate the outer periphery of the roll body to hold the web of material against the outer periphery with vacuum supplied to the at least one first vacuum hole by the vacuum passage. A first flow path (130, 230, 330, 430, 530, 630) of the vacuum hole extends at a first angle that is non-perpendicular to the rotational axis and is directed, at least in part, axially toward one of the first and second ends (112, 114) at the first outlet end (134, 234, 434, 534, 634) of the at least one first vacuum hole.