Sheet Manufacturing Apparatus Airflow Conduit Segmentation
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Solution Overview
Problem
Sheet manufacturing apparatuses using wet slurry methods require large amounts of water, are labor-intensive to maintain, and consume significant energy, while dry process machines face challenges in achieving uniform grammage due to uneven air flow velocities in material supply conduits.
Innovation Solution
A sheet manufacturing apparatus with a rotatable foraminous drum unit and a material supply conduit system that adjusts air flow velocities and conduit geometry to reduce material accumulation and improve web thickness uniformity, using a combination of air flow and gravity to convey fibers evenly onto the drum.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high air flow velocity is used in the material supply conduit, then material can be conveyed efficiently, but material accumulates in the conduit and web thickness uniformity deteriorates
Solution Approach 1:
The material supply conduit is divided into multiple sections with different cross-sectional areas. The conduit has a first section with a first cross-sectional area and a second section with a second cross-sectional area that is larger than the first. This segmentation allows different air flow velocities in different sections, enabling efficient material conveyance in the first section while reducing velocity and preventing accumulation in the second section near the drum unit.
Solution Approach 2:
Different sections of the material supply conduit are designed with different local properties (cross-sectional areas). The first section has a smaller cross-sectional area for higher velocity conveyance, while the second section has a larger cross-sectional area for lower velocity deposition. This local quality variation optimizes both material transport efficiency and web thickness uniformity at different locations along the conduit.
2Manufacturing precision
If low air flow velocity is used in the material supply conduit, then material accumulation is reduced, but material conveyance efficiency decreases
Solution Approach 1:
The conduit is segmented into two functional zones: a first section for high-velocity material conveyance and a second section for low-velocity uniform deposition. This segmentation resolves the contradiction by allowing each section to operate at the optimal velocity for its specific function, maintaining both productivity and manufacturing precision.
Solution Approach 2:
The solution transitions from a single uniform conduit design to a multi-dimensional design where the cross-sectional area varies along the length of the conduit. By introducing this dimensional variation, the system can accommodate different velocity requirements at different positions, simultaneously achieving efficient conveyance and uniform web formation.
3Adaptability or versatility
If the material supply conduit is long, then material can be supplied from a distance, but material residue increases and uniformity deteriorates
Solution Approach 1:
The conduit design applies different local qualities along its length, with the first section optimized for transport (smaller cross-section) and the second section optimized for deposition (larger cross-section). This allows the conduit to be sufficiently long for flexible material supply while ensuring that the critical deposition zone maintains optimal flow conditions for grammage uniformity.
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 enables the production of sheets with uniform grammage while minimizing material residue in the supply conduit, reducing energy consumption and equipment size by optimizing air flow and using gravity to assist in fiber distribution.
Implementation Method 1
a material supply conduit having a connector that connects to the drum unit, and carrying material including fiber into the drum unit by air flow
Implementation Method 2
using a combination of air flow and gravity to convey fibers evenly onto the drum
Data Source
AI summary
A sheet manufacturing apparatus suppresses material being left in a material supply conduit while manufacturing sheets with uniform grammage. A sheet manufacturing apparatus includes: a rotatable, foraminous drum unit; a web forming unit configured to form a web using material including fiber that has passed through the holes in the drum unit; and a material supply conduit having a connector that connects to the drum unit, and carrying material including fiber into the drum unit by air flow; the velocity of the flow in the connector being lower than the velocity of the flow on the upstream side of the connector.