An active carbon filter for an air vent assembly
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Solution Overview
Problem
Residential air handling units face challenges in accommodating large filtration units due to spatial constraints, requiring a solution that maximizes active carbon filter surface area while minimizing pressure drop and size to ensure effective NOx filtration without increasing fan power or unit size.
Innovation Solution
A cylindrical active carbon filter with a tapered outer and inner wall design, increasing the exposed surface area within the air duct, allowing for a higher carbon volume without increasing the filter's overall size, and enabling efficient airflow and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the amount of active carbon is increased to improve NOx filtration efficacy, then the filtration performance is improved, but the pressure drop across the filter increases and the unit size becomes too large for standard ceiling voids
Solution Approach 1:
The patent transitions from a traditional flat disc-shaped filter to a three-dimensional cylindrical filter that protrudes into the duct cross-section. This dimensional change allows the active carbon to be arranged in a volumetric configuration rather than a planar one, increasing the effective filtration surface area and carbon volume while maintaining a compact footprint that fits within standard ceiling voids.
Solution Approach 2:
The cylindrical filter design nests the active carbon particles within a cylindrical housing structure that is itself nested within the air duct. The housing includes an outer cylindrical wall with an open end facing the duct, creating a nested configuration that maximizes the use of available space while maintaining structural integrity and facilitating airflow through the carbon bed.
2Reliability
If the amount of active carbon is increased to improve NOx filtration efficacy, then the filtration performance is improved, but the unit size increases beyond what can be accommodated in standard ceiling voids
Solution Approach 1:
The patent transitions from a traditional flat disc-shaped filter to a three-dimensional cylindrical filter that protrudes into the duct cross-section. This dimensional change allows the active carbon to be arranged in a volumetric configuration rather than a planar one, increasing the effective filtration surface area and carbon volume while maintaining a compact footprint that fits within standard ceiling voids.
Solution Approach 2:
The filter design concentrates the active carbon filtration function in a localized cylindrical volume within the duct, rather than spreading it out in a large planar area. This localizes the high-value filtration function to a compact three-dimensional space that can be accommodated in standard ceiling voids, while still providing sufficient carbon volume for effective NOx removal.
3Ease of manufacture
If a standard disc-shaped cylindrical filter is used, then the structure is simple and easy to manufacture, but the exposed surface area within the duct is limited, restricting the amount of active carbon that can be used
Solution Approach 1:
The patent transitions from a traditional flat disc-shaped filter to a three-dimensional cylindrical filter that protrudes into the duct cross-section. This dimensional change allows the active carbon to be arranged in a volumetric configuration rather than a planar one, increasing the effective filtration surface area and carbon volume while maintaining a compact footprint that fits within standard ceiling voids.
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 tapered design reduces pressure drop across the filter, maintains effective NOx filtration, and allows for a higher carbon volume within standard ceiling voids, enhancing the ventilation system's efficiency and extending maintenance intervals.
Implementation Method 1
an active carbon filter to treat NOx gases
Implementation Method 2
The diameter of at least the outer wall of the housing tapers from a first diameter at the outlet end to a smaller second diameter at the inlet end such that the outer wall is spaced from the duct along at least part of its length to allow air flowing through the duct to flow into the perforations of the outer wall, across the active carbon material
Data Source
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AI summary
An active carbon filter for an air vent assembly comprises a cylindrical housing that in use is located within an air supply duct. The housing has a height, a diameter, an inlet end and an outlet end. The housing comprises a perforated outer wall and a perforated inner wall spaced inwardly from the outer wall. The spacing between the inner and outer walls defines a void within which an active carbon material is contained. The diameter of the outer wall of the housing tapers from a larger first diameter at the outlet end to a smaller second diameter at the inlet end such. The outer wall is therefore spaced from the duct along at least part of its length to allow air flowing through the duct to flow into the perforations of the outer wall, across the active carbon material and out of the perforations in the inner wall, with the tapered form of the outer wall increasing the exposed surface area of the outer wall to increase the surface area of the active carbon and decrease the pressure drop across the filter for a given volume of carbon.