Extended Pleat Air Filter Reducing Pressure Drop

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Solution Overview

Problem

Standard air filters in ventilation systems face challenges in achieving high filtration efficiency without increasing energy consumption or requiring costly modifications to the return air grille and ductwork.

Innovation Solution

An extended pleat air filter design that fits within a standard return air grille, utilizing a housing with a gasket flange and an accordion-like pleat filter medium made from reinforced non-woven fibers, which increases the filter surface area and reduces pressure drop while maintaining airflow efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a larger fan is installed to overcome increased pressure drop from higher efficiency air filters, then filtration efficiency is improved, but energy consumption increases and fan life is reduced

Engineering Contradiction:

Improvefiltration efficiencyVSAvoidenergy consumption

Core Design Contradiction:

ReliabilityVSUse of energy by moving object

Solution Approach 1:

The filter medium is extended from a single flat surface into a three-dimensional pleated structure, increasing the filtration surface area by utilizing spatial dimensionality. This allows more filtration surface to be packed into the same filter depth, reducing pressure drop without requiring a larger fan

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The pleated filter medium is nested within the housing, with each pleat contained within the volume defined by the housing walls. The accordion-like folding allows maximum surface area to be nested within the constrained depth of a standard return air grille

Inventive Principle:

Principle #7Nested doll (Nesting)

2Reliability

If a larger fan is installed to overcome increased pressure drop from higher efficiency air filters, then filtration efficiency is improved, but fan life is reduced

Engineering Contradiction:

Improvefiltration efficiencyVSAvoidfan life

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The pleated structure increases surface area by utilizing the third dimension (depth), allowing more filtration surface without increasing the fan workload, thereby preserving fan life while maintaining high filtration efficiency

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If the return air grille is modified to accommodate an air filter with greater surface area, then filtration efficiency is improved, but manufacturing cost increases and installation becomes difficult

Engineering Contradiction:

Improvefiltration efficiencyVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The filter is designed to fit within the standard return air grille configuration, making it universally compatible with existing installations. The pleated structure provides high surface area within the conventional one-inch depth, eliminating the need for custom modifications to ductwork or grilles

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

By extending the filter surface into the depth dimension through pleating, the design achieves high filtration efficiency within the standard one-inch depth constraint, avoiding the need to modify the return air grille or ductwork

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 extended pleat air filter achieves enhanced filtration efficiency with reduced pressure drop, extending service life and minimizing the need for fan upgrades or ductwork modifications, thus offering a cost-effective solution for high-efficiency air filtration.

Implementation Method 1

The pleat filter medium is formed from a reinforced non-woven fiber sheet and has an accordion-like folded configuration that increases the filter surface area presented to the air flow

Methodology Applied

Scientific EffectPressure drop reduction through increased surface area:

Implementation Method 2

Air filters provide two important functions in any ventilation system, the first function is to remove particulates from the air circulating through the system

Methodology Applied

Scientific EffectPhysical filtration: Filter (physical)

Implementation Method 3

The housing is surrounded by a gasket flange that forms a seal between the housing and the return air grille

Methodology Applied

Scientific EffectSealing:

Data Source

PatentUS7727299B2Extended surface pleat air filter

Publication Date: 2010.06.01 FILTRATION MFG

AI summary

A high efficiency air filter for use in a standard return air grille is provided. Standard return air grilles possess filter receptacles for accepting air filters, a closeable cover with a cover flange for engaging air filters and a duct interface that leads away from the air grille to the remainder of the return air ducts. The air filter has a filter flange with a gasket that is sized to fit within the filter receptacle of the air grille, such that when the cover is closed, the cover flange seals against the cover and the filter receptacle. The gasket is affixed to a housing that is sized to extend beyond the filter receptacle into the duct extending beyond the return air grille. An extended pleat air filter is contained within and sealed to the walls of the housing such that air passing through the return air grille substantially passes through the air filter prior to entering the remainder of the return air duct.