Secondary Filter Cartridge With Gradient Pleat Depth

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Solution Overview

Problem

Existing air filter assemblies face challenges in the configuration and operation of secondary or safety filter cartridges, particularly in terms of size, shape, and interaction with main filter cartridges, leading to limitations in airflow and increased restriction, as well as difficulties in convenient assembly and service without dislodging the safety filter.

Innovation Solution

The introduction of a secondary or safety filter cartridge design with a media configuration featuring minimal pleats at one end and deeper pleats at the other, along with a media support structure and housing features that facilitate secure installation and sealing, allowing for efficient airflow and easy assembly while minimizing radial dimension and restriction.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a secondary or safety filter cartridge is included within the filter assembly, then filtration reliability is improved, but radial dimension and airflow restriction increase

Engineering Contradiction:

Improvefiltration reliabilityVSAvoidairflow restriction

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent applies local quality by varying the pleat depth along the length of the filter media. The media features shallower pleats near the outlet end and deeper pleats toward the inlet end, creating different local filtration densities. This allows the filter to maintain reliability while optimizing airflow characteristics at different stages of filtration.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent transitions from a uniform radial configuration to an asymmetric radial configuration by varying pleat depth along the axial dimension. This dimensional variation allows the filter to pack more media surface area into the available radial space while maintaining acceptable pressure drop characteristics.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Reliability

If a secondary or safety filter cartridge is included within the filter assembly, then filtration reliability is improved, but the device complexity increases

Engineering Contradiction:

Improvefiltration reliabilityVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the secondary safety filter cartridge with the main filter cartridge by positioning the safety filter media within the same housing and support structure. The safety filter media is integrated into the existing filter assembly architecture, sharing common components such as the end caps, support ribs, and sealing surfaces, thereby reducing overall device complexity.

Inventive Principle:

Principle #5Merging (Combining)

3Reliability

If the media is pleated to increase surface area, then filtration effectiveness is improved, but radial dimension and restriction increase

Engineering Contradiction:

Improvefiltration effectivenessVSAvoidradial dimension

Core Design Contradiction:

ReliabilityVSLength of stationary object

Solution Approach 1:

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent changes the geometric parameters of the pleats along the media length. By transitioning from shallow pleats to deep pleats in a gradient fashion, the filter media optimizes the balance between surface area density and airflow passage, increasing filtration effectiveness without proportionally increasing radial dimension.

Inventive Principle:

Principle #35Parameter changes

4Ease of repair

If the safety filter cartridge is configured to be removable and serviceable, then ease of maintenance is improved, but assembly complexity and potential for dislodgement increase

Engineering Contradiction:

Improveease of maintenanceVSAvoidassembly complexity

Core Design Contradiction:

Ease of repairVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the safety filter cartridge with the same releasable seal configuration as the main filter cartridge. Both filters use identical sealing surfaces, grommets, and engagement features with the housing, allowing either filter to be independently installed, removed, and serviced without requiring different assembly procedures or specialized components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 configuration enhances airflow by reducing radial dimension and restriction, increases media surface area for effective filtration, and allows for convenient assembly and service of the main filter without disturbing the safety filter, improving the overall performance and efficiency of the air filter assembly.

Implementation Method 1

Filtration is generally conducted with a gas (air) cleaner assembly (i.e. a filter assembly) typically including a housing and an internally positioned filter cartridge arrangement. The filter cartridge arrangement typically includes a main filter cartridge, through which the air is passed and which is operated with deposition of particulate material carried therein onto filter media of a main filter cartridge.

Methodology Applied

Scientific EffectFiltration: Filter (physical)

Data Source

PatentUS11192053B2Filter cartridges; features and methods of assembly; air cleaner assemblies; and, filter cartridge combinations

Publication Date: 2021.12.07 DONALDSON CO INC

AI summary

Filter cartridge arrangements, features thereof and assembly for use therewith, are provided. Selected filter cartridge features are disclosed. Methods of assembly and systems for use are described.