Filter Supporting Grid With Variable Cross Section
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Solution Overview
Problem
Existing air filtration filters with supporting grids face challenges in maintaining structural integrity and minimizing pressure drop due to deflection, despite providing some support against deformation.
Innovation Solution
A filter design featuring a supporting grid with non-perpendicular rods or beams within an angular medium frame, where the second area moment is optimized by varying cross-sectional height along the rod, being smaller towards the sides than the center, enhancing stiffness and load-bearing capacity with reduced material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a supporting grid with uniform cross-section rods is used, then the filter medium is supported against deformation, but the pressure drop increases and material usage is excessive
Solution Approach 1:
The supporting rods are designed with variable cross-sectional areas along their length, with larger cross-sections at the center where bending moments are highest and smaller cross-sections towards the edges. This local variation in structural properties optimizes the supporting capacity while reducing unnecessary material usage and minimizing pressure drop across the filter medium.
Solution Approach 2:
The cross-sectional parameters of the supporting rods are changed along their length to match the distribution of mechanical stresses. By varying the cross-sectional area parameter, the rods achieve optimal stiffness and load-bearing capacity where needed while reducing material in less critical areas, thereby lowering overall pressure drop and material consumption.
2Stability of the object's composition
If supporting rods extend perpendicular to side edges, then structural support is provided, but deflection control is insufficient at diagonal positions
Solution Approach 1:
The supporting rods are oriented at angles other than perpendicular to the side edges of the rectangular frame, creating an asymmetric support pattern. This asymmetric arrangement provides better distribution of support forces across the filter medium, particularly improving deflection control at diagonal positions where perpendicular rods would provide insufficient support.
3Ease of manufacture
If uniform cross-sectional rods are used throughout, then manufacturing is simple, but material expenditure is excessive
Solution Approach 1:
The supporting rods feature non-uniform cross-sectional areas along their length, with larger sections positioned at the center and smaller sections towards the edges. This local differentiation in cross-sectional dimensions reduces overall material expenditure while maintaining adequate supporting capacity, as material is concentrated where structural demands are highest.
Solution Approach 2:
The cross-sectional parameters of the rods are varied along their length to match the stress distribution pattern. By changing the cross-sectional area parameter from center to edge, the design achieves optimal material efficiency - using more material where needed for structural integrity and less material where lower stresses occur, thereby reducing total material expenditure.
Data Source
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AI summary
A filter comprises a filter medium held in an angular medium frame and has a downstream face with respect to a direction of flow of the filter. The filter medium is supported on the downstream face by means of a supporting grid which in turn is supported with its side edges on the angular medium frame. The supporting grid comprises a supporting structure with at least one supporting rod extending not perpendicularly to the side edges of the angular medium frame. The supporting structure has a second area moment. The second area moment of the supporting structure is smaller towards the side edges of the angular medium frame than towards the centre of the support structure.