Kitchen Hood Impact Filter With Grease Trap for Fine Particle Capture
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Solution Overview
Problem
Existing kitchen exhaust systems struggle to efficiently remove small grease particles and sticky contaminants from air streams, as known filters are ineffective for particles smaller than 10 microns and require frequent cleaning, leading to high maintenance costs and contamination of ducting.
Innovation Solution
The application of impactor technology in an impact filter design, which uses differential inertia to separate grease and cooking residues from air streams by accelerating the air and particles through a nozzle, with a baffle system to collect and drain contaminants, preventing re-entrainment and allowing for continuous removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If known filters and screens are used to remove grease particles, then large particles (10 microns and larger) can be removed, but small grease particles cannot be captured effectively
Solution Approach 1:
The patent changes the fundamental operating parameter from passive filtration to active inertial impaction. By accelerating the air stream through a nozzle to high velocity and directing it at an impact surface, the system achieves effective capture of small particles (below 10 microns) that cannot be captured by conventional filters. The Stokes number calculation guides the selection of nozzle characteristics to optimize particle removal at specific size thresholds.
Solution Approach 2:
The patent replaces the mechanical filtration system (screens and filters) with an inertial impaction system. Instead of relying on physical barriers to trap particles, the system uses the inertia of particles in a high-velocity air stream to carry them against an impact surface, where they are collected by gravity drainage. This mechanical substitution enables effective capture of small grease particles that pass through conventional filters.
2Reliability
If conventional grease filters are used, then grease removal is achieved, but frequent cleaning is required leading to high maintenance costs
Solution Approach 1:
The patent extracts the collected grease and contaminants from the impact surface through gravity drainage. The impact surface is designed with a drainage mechanism that continuously or periodically removes accumulated grease, preventing buildup and eliminating the need for frequent manual cleaning. This extraction principle transforms the filter from a maintenance-intensive component to a self-cleaning system.
Solution Approach 2:
The impact filter implements self-service through automatic gravity drainage of collected grease. The system continuously removes contaminants without requiring external intervention or frequent manual cleaning, significantly reducing maintenance time and costs while maintaining effective grease removal performance.
3Reliability
If conventional filters are used, then some contaminant removal is achieved, but substantial contaminants deposit on ducting requiring frequent cleaning
Solution Approach 1:
The patent applies preliminary action by removing a substantial portion of contaminants early in the exhaust system, before the air enters the ducting. The impact filter is positioned at the exhaust hood to capture grease and particles at the source, preventing them from traveling through and depositing on duct surfaces. This preliminary removal action significantly reduces duct contamination and the associated cleaning requirements.
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 impact filter effectively captures small grease particles and other contaminants, reducing the frequency of maintenance and minimizing duct contamination, while maintaining high efficiency in particle separation and continuous contaminant removal.
Implementation Method 1
Inertia of particles heavier than air carries the particles against or close to an impact surface. However, the air stream having negligible inertia turns more quickly.
Implementation Method 2
uses differential inertia to separate grease and cooking residues from air streams by accelerating the air and particles through a nozzle
Implementation Method 3
The particles of greater mass deviate from the air stream and hit the impact surface.
Implementation Method 4
with a baffle system to collect and drain contaminants
Data Source
Figure 1
Figure 2
Figure 3~14
AI summary
An impact filter suitable for a kitchen exhaust hood is provided with a grease trap to capture grease particles and channel the particles away. The trap can be of different configurations. The filter can be used in various system layouts.