Expanded Metal Pleat Stability via Diamond Shape Control
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Solution Overview
Problem
Conventional expanded metal used in filters tends to spring back to its original shape after pleating, resulting in inconsistent pleat heights and increased risk of pleat collapse under air pressure, leading to premature filter failure and reduced performance.
Innovation Solution
The expanded metal is formed with a unique process where the base plate is fed through a cutting die and stretched beyond its plastic yield point, altering the diamond shape dimensions to have a short dimension equal to or greater than the long dimension, and further stretched by at least 15% to 30% to reduce the long dimension significantly, enhancing the material's strength and consistency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional expanded metal is used in filters, then the filter can be manufactured with expanded metal, but the expanded metal springs back to its original shape after pleating, resulting in inconsistent pleat heights and increased risk of pleat collapse
Solution Approach 1:
The patent applies parameter changes by modifying the diamond shape dimensions of the expanded metal, specifically making the long dimension less than twice the short dimension (LWD < 2×SWD). This geometric parameter change alters the material's mechanical properties, reducing spring back and enabling consistent pleat heights while maintaining structural stability under air pressure
Solution Approach 2:
The patent applies preliminary action through the stretching process performed before the expanded metal is used in filter manufacturing. The metal is stretched by at least 15% to 30% to reduce the long dimension and achieve the desired LWD < 2×SWD ratio, pre-conditioning the material to minimize spring back during subsequent pleating operations
2Ease of manufacture
If conventional expanded metal with LWD twice the SWD is used, then the expanded metal can be easily manufactured, but the pleats have increased chance to collapse during filtering due to air pressure
Solution Approach 1:
The patent changes the geometric parameters of the expanded metal diamonds from the conventional LWD = 2×SWD ratio to LWD < 2×SWD ratio. This parameter modification strengthens the pleat structure against air pressure collapse while maintaining manufacturability through adjusted stretching processes
Solution Approach 2:
The patent creates a composite structure by combining the expanded metal with filter media in a way that the modified diamond geometry (LWD < 2×SWD) provides structural support. The strengthened pleats act as a composite framework that prevents collapse under operating conditions
3Productivity
If conventional expanded metal is pleated, then the filter can be formed, but there are less contact points between the pleat peaks and bonds, causing filter fluttering or possible pleat collapsing
Solution Approach 1:
The patent modifies the diamond geometry parameters to increase the number of contact points between pleat peaks and bonds. By adjusting the LWD and SWD ratio to achieve LWD < 2×SWD, the design creates more frequent bonding points along the pleat length, enhancing structural integrity and eliminating fluttering
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 process produces a stronger, lighter expanded metal with minimal spring back, resulting in consistent pleat heights and reduced material usage, enhancing filter stability and performance by minimizing recoil and maintaining pleated shape, thus reducing filter-induced pressure drops and flow restrictions.
Implementation Method 1
a desired strand thickness 26 beyond an edge 29 of the support base (FIG. 2B), a serrated cutting die 28 descends and simultaneously shears, slits and cold forms an entire row 30 of half-diamonds 32
Implementation Method 2
at least a portion of the metal is expanded beyond in plastic yield point
Implementation Method 3
The flattening rolls also pinch and pull on the expanded metal typically at a rate faster than the rate of the expanded metal exiting the expander
Implementation Method 4
The expanded metal is formed with a unique process where the base plate is fed through a cutting die and stretched beyond its plastic yield point, altering the diamond shape dimensions
Data Source
AI summary
An expanded metal is provided including a plurality of integral strands defining diamond shapes, each diamond shape having a long dimension as measured from two opposing vertices and a short dimension, generally transverse to the long direction, as measured between two other opposing vertices, such that the long dimension is less than twice the short dimension.