NACA Duct Boundary-Layer Dust Removal for Moving Paper Webs
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Solution Overview
Problem
Existing dust removal methods in paper machines are inefficient, power-consuming, noisy, and can dislodge fibers, leading to product quality issues, maintenance problems, and health hazards due to airborne dust.
Innovation Solution
A NACA duct system is positioned non-contactingly on a moving web to scavenge particulate-carrying air from the boundary layer, using a curved intake opening and exhaust opening to guide dust-laden air without disrupting the web, and can be supplemented with vacuum assistance for enhanced dust removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If vacuum is applied to the web surface to remove dust, then dust removal effectiveness is improved, but fibers are partially dislodged creating loose or loosened fibers which become airborne downstream
Solution Approach 1:
The invention extracts only the dust-laden boundary layer air from near the web surface using a hood positioned close to the web, without applying direct vacuum to the web itself. This separates the dust removal function from the web, preventing fiber dislodgement while still achieving effective dust capture through the hood's proximity to the dust source.
Solution Approach 2:
The hood acts as an intermediary device that captures dust-laden air indirectly. Instead of applying vacuum directly to the web (which causes fiber loosening), the hood positioned near the web surface serves as a mediator that intercepts the boundary layer containing dust particles, allowing dust removal without direct web-vacuum interaction.
2Object-affected harmful factors
If dust hoods are used to vacuum dust laden air, then dust removal is achieved, but substantial power consumption and noise are generated
Solution Approach 1:
The hood is positioned locally close to the web surface where dust is generated, creating a localized dust capture zone. This local positioning allows the system to capture dust at its source with lower vacuum pressure requirements, reducing overall power consumption compared to large-scale atmospheric dust collection systems.
3Object-affected harmful factors
If vacuum is applied to remove dust, then dust removal effectiveness is improved, but the system becomes a source of noise
Solution Approach 1:
The invention extracts dust-laden air locally at the web surface using a positioned hood, eliminating the need for large vacuum systems that generate significant noise. By taking out only the necessary boundary layer air close to the source, the system achieves dust removal with minimal noise generation.
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 NACA duct system effectively removes dust from the boundary layer without disturbing the web, reducing maintenance needs, improving product quality, and minimizing health and fire hazards while being power-efficient and environmentally friendly.
Implementation Method 1
a NACA duct positioned in a non-contacting relationship on a first side of the moving web, and at least partially submerged in a particulate-carrying boundary layer of the moving web
Data Source
AI summary
An apparatus for removing particulate-carrying air from a moving web. The moving web has a first side and a second side. The apparatus includes a NACA duct positioned in a non-contacting relationship on a first side of the moving web, and at least partially submerged in a particulate-carrying boundary layer of the moving web. The NACA duct can have an intake opening and an exhaust opening such that when the intake opening is submerged in the boundary layer at least a portion of the particulate-carrying air from the boundary layer enters the intake opening and exits the exhaust opening, thereby scavenging particulate-carrying air from said boundary layer.