TAD Paper Dust Control via Zoned Vacuum Hoods
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Solution Overview
Problem
Through-air drying papermaking machines produce excessive dust, leading to operational challenges and safety issues due to the high speed and use of recycled fibers, which are not effectively managed by existing dust control systems.
Innovation Solution
A dust control system comprising a series of vacuum hoods and baffles strategically placed along the papermaking path, with airflow rates adjusted based on dust accumulation, and air ramps to direct dust into control zones, ensuring efficient capture and removal of dust.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If through-air drying is used to produce bulkier, softer tissue sheets, then product quality is improved, but dust production increases enormously
Solution Approach 1:
The dust control system is divided into multiple vacuum hoods positioned at different locations along the papermaking machine, each handling dust from specific zones. This segmentation allows targeted dust capture without interfering with the through-air drying process that produces high-quality tissue sheets.
Solution Approach 2:
Vacuum hoods act as intermediary devices between the dust-generating papermaking process and the dust collection system. These hoods capture dust at the source using controlled airflow, preventing dust dispersion while maintaining the beneficial effects of through-air drying on sheet quality.
2Object-generated harmful factors
If vacuum hoods are placed around the papermaking machine to control dust, then dust capture is improved, but airflow uniformity across the web becomes problematic
Solution Approach 1:
Each vacuum hood is designed with locally optimized airflow characteristics tailored to its specific position on the machine. Hoods at different locations have different airflow rates and configurations matched to the dust generation patterns in their respective zones, ensuring effective dust capture without creating non-uniform airflow across the entire web.
Solution Approach 2:
The system uses adjustable airflow controls on each vacuum hood to dynamically balance the airflow across different sections of the web. This allows the system to adapt to varying dust generation conditions while maintaining overall airflow uniformity and preventing web distortion.
3Productivity
If high-speed operation is used to increase productivity, then output is improved, but dust generation increases due to fiber breakage
Solution Approach 1:
Vacuum hoods are positioned to capture dust at the source before it can disperse throughout the machine environment. By placing hoods strategically along the papermaking path, dust from high-speed fiber breakage is captured immediately, allowing continuous high-speed operation without shutdowns for dust clearance.
Solution Approach 2:
The dust control system operates continuously alongside the high-speed papermaking process, maintaining constant dust capture capability. This allows the machine to run at high productivity levels without interruption, as the vacuum system continuously removes dust generated by fiber breakage rather than requiring periodic shutdowns for dust removal.
4Object-generated harmful factors
If multiple shutdowns are performed to clear dust, then dust accumulation is reduced, but productivity and operational efficiency decrease
Solution Approach 1:
The vacuum hood system provides continuous self-service dust removal during normal operation, eliminating the need for scheduled shutdowns to clear dust accumulation. The system automatically captures and removes dust as it is generated, maintaining clean operating conditions throughout production cycles and preserving operational efficiency.
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 system significantly reduces dust accumulation and prevents fires by effectively capturing and containing dust, allowing for continuous operation with improved safety and reduced maintenance interruptions.
Implementation Method 1
A dust control system for the "dry" end of a through-air drying (TAD) papermaking system uses a belt to move a web of formed paper or tissue from a Yankee cylinder onto a parent roll. A series of dust hoods are placed in specific locations along the path of the belt
Implementation Method 2
The airflow through each hood is predetermined based on its position, with hoods in higher-dust areas having higher airflows
Implementation Method 3
Baffles are provided between certain hoods, and between hoods and certain other elements of the machine, in order to create dust-control zones around the hoods, and air ramps and other elements may be used to drive dust into the dust control zones and toward the hoods
Data Source
AI summary
One aspect of the invention relates to a dust control system for the “dry” side of a through-air drying (TAD) papermaking system. A series of dust hoods are placed in specific locations, both above and below the web of paper or tissue that is being manufactured. Each hood spans at least a substantial portion of the width of the belt or web, and each hood is shaped and otherwise adapted for its particular position, both to accommodate the structure of the papermaking machine and to ensure that the airflow through the inlet of the hood is substantially uniform across its entire width. Baffles are provided between certain hoods in order to create dust-control zones around the hoods, and air ramps and other elements may be used to drive dust into the dust control zones and toward the hoods.