Curved Exhaust Duct Flow Control for Uniform Filter Loading
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Solution Overview
Problem
In image forming devices, curved exhaust ducts disrupt gas flow to filters, leading to uneven distribution and reduced filtration efficiency, which is exacerbated by the need to minimize environmental discharge of substances like odor and ultra-fine particles.
Innovation Solution
An exhaust device with a curved portion in the duct includes a filter on the downstream side and features plate-shaped flow control members on the inner wall of the curved portion, forming an inverted V shape to guide gas flow uniformly, ensuring even distribution across the filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a curved portion is provided in the exhaust duct to reduce device size or adapt to structural constraints, then the exhaust device becomes more compact or adaptable, but the gas flow becomes unbalanced and filtration efficiency deteriorates
Solution Approach 1:
A flow control member is introduced as an intermediary component between the curved exhaust duct and the filter. This member has a specific shape (with a convex portion facing the curved duct) that actively mediates the disturbed gas flow, redirecting it to achieve uniform distribution across the filter surface, thereby resolving the contradiction between compact design and filtration efficiency
Solution Approach 2:
The flow control member features a non-uniform shape with a convex portion specifically positioned to face the curved portion of the exhaust duct. This local structural variation is designed to counteract the specific flow disturbance pattern created by the curve, creating locally optimized flow conditions that result in overall uniform filtration
2Reliability
If a flow control unit is added to uniformize gas flow into the filter, then filtration efficiency is improved, but device complexity increases
Solution Approach 1:
The flow control member's shape parameters (particularly the convex portion's curvature and positioning) are specifically designed to match and counteract the flow disturbance parameters created by the curved exhaust duct. By changing geometric parameters rather than adding complex mechanical control systems, the patent achieves flow uniformization with minimal added complexity
Data Source
AI summary
An exhaust fan, an exhaust duct through which a discharged gas flows and a filter which is provided in the exhaust duct are included. A curved portion is provided in the exhaust duct, and the filter is provided on a downstream side in a direction of flow of the gas with respect to the curved portion. On an inside wall of the curved portion of the exhaust duct on an outer side in a radial direction, a first flow control member that uniformizes the amount of the gas flowing through the filter is provided so as to be perpendicular to the shaft of the curved portion, and a space is formed between the first flow control member and an inside wall of the curved portion on an inner side in the radial direction.