Feathered Baffle Filter with Undulating Edges to Reduce Exhaust Noise
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Solution Overview
Problem
Conventional grease filters in kitchen exhaust hoods with straight-edged baffles generate significant noise and are less effective in grease collection due to uniform airflow, which disrupts and reduces cavitation.
Innovation Solution
The use of baffles with undulating or scalloped edges in the filter design disrupts airflow, mimicking the wing shape of owl wings, reducing noise and enhancing grease collection by creating gaps for airflow and increasing surface contact with grease particles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If baffles with straight edges are used in the filter, then the filter structure is simple and easy to manufacture, but the noise generated by exhaust gases passing through the filter is significant
Solution Approach 1:
The patent applies curvature by replacing straight edges with undulating or scalloped edges on the baffles. This curved geometry disrupts the airflow of exhaust gases in a controlled manner, reducing noise generation while maintaining the baffle's structural simplicity and manufacturability. The undulating pattern creates multiple small surfaces that deflect gases smoothly rather than creating turbulent noise from sharp edges.
2Device complexity
If baffles with straight edges are used in the filter, then the filter structure is simple, but the grease collection efficiency is reduced due to uniform airflow
Solution Approach 1:
The undulating or scalloped edge geometry creates non-uniform airflow patterns as exhaust gases pass through the filter. This disrupted flow increases turbulence and cavitation effects, which enhance the separation and collection of grease particles from the gas stream, improving productivity without significantly increasing structural complexity.
Solution Approach 2:
The patent applies local quality by creating variations in the baffle edge geometry. The undulating pattern provides different surface orientations and airflow interaction zones across the baffle surface, with some areas creating stronger turbulence and others providing smoother flow paths. This localized variation in flow characteristics optimizes grease collection across the entire filter surface.
3Object-affected harmful factors
If baffles with undulating or scalloped edges are used in the filter, then noise is reduced and grease collection is improved, but the manufacturing complexity increases
Solution Approach 1:
The undulating or scalloped edge pattern, while geometrically more complex than straight edges, can be manufactured using standard forming processes such as stamping, rolling, or extrusion. The repetitive nature of the pattern allows for efficient tooling and production, minimizing the increase in manufacturing complexity while achieving the desired noise reduction and grease collection improvements.
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 undulating edge design significantly reduces noise and improves grease collection efficiency by redirecting airflow and increasing surface contact, leading to a quieter operation and better filtration performance.
Implementation Method 1
embodiments of the invention collect more grease than conventional filters having baffles with straight edges due to increase airflow, disrupted airflow, and increased cavitation of the airflow
Data Source
AI summary
A filter for an exhaust hood includes: a frame extending in a first direction and a second direction; a first baffle located in the frame, the first baffle extending in the first direction and having two edges that extend in the first direction, a first edge of the two edges of the first baffle having a first undulating shape, a second edge of the two edges of the first baffle having a second undulating shape; and a second baffle located in the frame, the second baffle extending in the first direction and having two edges that extend in the first direction, a first edge of the two edges of the second baffle having a third undulating shape, a second edge of the two edges of the second baffle having a fourth undulating shape. The first baffle and the second baffle are separated by a gap.