Angled Upper Walls Prevent Gas Bypass in Particulate Filters
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Solution Overview
Problem
Conventional gas filters with particulate media, such as carbon, suffer from 'bypass' issues where air passes through gaps created by settling particulate matter, leading to poor VOC and odor removal efficiency due to insufficient contact between gas and filtration medium.
Innovation Solution
The filter design features angled upper walls that maintain contact between the particulate and the upper wall surface, even when the filter is vertically oriented, ensuring all gas flows through the particulate bed by orienting the upper wall surface at angles greater than 93 degrees relative to the upstream face, preventing the formation of bypass paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional perpendicular upper walls are used in vertically oriented filters, then manufacturing is simple, but gas bypasses through gaps formed by settling particulate matter
Solution Approach 1:
The upper walls are angled relative to the vertical axis rather than being perpendicular, creating an asymmetric configuration that prevents bypass while maintaining structural integrity. This asymmetric design ensures that settling particulate cannot form continuous gaps from upstream to downstream faces.
Solution Approach 2:
The solution introduces a new geometric dimension by angling the upper walls at specific angles (e.g., 5-15 degrees from vertical), transforming the conventional perpendicular structure into an inclined configuration that blocks bypass paths created by gravitational settling.
2Reliability
If angled upper walls are used to prevent bypass, then filtration efficiency improves, but manufacturing complexity increases
Solution Approach 1:
The invention specifies optimal angle ranges (5-15 degrees from vertical) that balance bypass prevention with manufacturability. By defining specific parameter ranges rather than arbitrary angles, the design achieves filtration efficiency while remaining practical for fabrication using conventional processes.
3Stability of the object's composition
If particulate settles in vertical orientation, then gravity acts naturally, but gaps form allowing gas to bypass the filtration medium
Solution Approach 1:
The angled upper walls are designed in advance to counteract the bypass effect of gravitational settling. By pre-configuring the wall angles before the filter is installed and particulate settles, the structure proactively prevents the formation of continuous gaps, ensuring gas must contact particulate even after settling occurs.
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 design ensures that nearly all gas flowing through the filter comes into contact with the particulate matter, significantly enhancing VOC and odor removal efficiency while minimizing pressure drop and particulate loss.
Implementation Method 1
Granular carbon is commonly used in such filters to capture odors and VOCs from air as the air is forced through a particulate bed
Implementation Method 2
Because of the force of gravity, within each baffle set, or cell, the carbon particulate may settle to the bottom of the cell
Data Source
AI summary
A filter contains fluent particulate, such as carbon granules. The filter is divided into a plurality of cell chambers by walls, including an upper wall. The upper wall has a surface that faces, and is closest to, the top surface of the particles. The upper wall surface is oriented so that, as the particles settle, any gap formed between the top surface of the particles and a portion of the upper wall surface will not extend from the upstream to the downstream sides of the filter. Instead, contact is maintained between the top surface of the particles and the upper wall surface during fluid flow through the filter, and therefore any gas flowing through the frame must flow through, and through spaces around, particles. An angle between the upper wall surface and the flow direction of gas striking the filter is greater than about three degrees.