Tubular Filter Element with Convex-Concave Arch Cross-Section

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Solution Overview

Problem

Cyclone filters have moderate filter performance for fine particles and are often used in multi-stage systems with conventional filter elements that are not optimized for air filtration post-cyclone, leading to turbulent airflow and reduced filter effectiveness due to suboptimal filter surface area and uneven flow.

Innovation Solution

A tubular filter element with a unique annular cross-section featuring convex and concave arches, providing a larger filter surface area and incorporating air guide fins and flow stabilization elements to calm airflow and enhance particle separation, while being adaptable for use with cyclone filters in multi-stage systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Area of stationary object

If conventional filter elements with planar, round or oval cross-sections are used, then the structure is simple, but the filter surface area is not optimal

Engineering Contradiction:
Improvefilter surface areaVSAvoidfilter element structure
Core Design Contradiction:
Area of stationary objectVSDevice complexity

Solution Approach 1:

The filter element employs a tubular design with an annular cross-section featuring convex and concave arches along its inner wall. This curved, non-planar geometry increases the filter surface area compared to conventional flat or simple rounded cross-sections, while maintaining a relatively simple overall tubular structure that can be manufactured using standard processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Reliability

If conventional filter elements are used downstream of cyclone filtration, then the system is simple, but the airflow remains turbulent reducing filter effectiveness

Engineering Contradiction:
Improvefilter effectivenessVSAvoidfilter element structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The inner wall of the tubular filter element features alternating convex and concave arches that create localized flow conditioning zones. The concave arches generate flow resistance and calm turbulence in specific regions, while the convex arches provide structural support. This localized modification of the flow path improves filter effectiveness without requiring complete redesign of the entire filter system.

Inventive Principle:
Principle #3Local quality

3Reliability

If the filter element interior is constricted at concave arches, then flow resistance increases calming turbulence, but the available flow cross-section decreases

Engineering Contradiction:
Improveflow stabilizationVSAvoidflow cross-section
Core Design Contradiction:
ReliabilityVSArea of stationary object

Solution Approach 1:

The filter element divides the airflow path into multiple segments through the alternating convex and concave arches along the tubular interior. This segmentation creates multiple smaller flow channels that individually provide flow resistance and turbulence calming, while collectively maintaining adequate total flow cross-section. The segmented approach allows flow stabilization without excessive restriction of overall airflow.

Inventive Principle:
Principle #1Segmentation

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 design significantly increases filter performance by stabilizing airflow, maximizing filter surface area, and improving particle discharge, making it suitable for both fine dust filtration and main filtration stages with reduced turbulence and improved space efficiency.

Implementation Method 1

The centrifugal forces acting on the particles accelerate them radially outwards. This separates them from the gas flow, which is directed inwards and discharged.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

The air pre-cleaned by the cyclone filtering is conveyed through the filter medium of the final filter, in particular a filter element, with impurities in the air being deposited on the filter medium.

Methodology Applied
Scientific EffectFiltration: Filter (physical)

Data Source

PatentEP2675547B1Air filter element, air filter housing, and air filter system
Publication Date: 2017.05.10 MANN HUMMEL GMBH
  • EP2675547B1 patent drawingFigure 1~2
  • EP2675547B1 patent drawingFigure 2A
  • EP2675547B1 patent drawingFigure 3~4C

AI summary

A filter element (1) for an air filter (30) comprises a tubular filter medium (2), the annular cross-section of which encloses an interior (6) of the filter element and which has an inner wall (7) that adjoins the interior of the filter element and that extends in the form of at least one convex arch (8) and at least two concave arches (9), the concave arch (9) being located between two convex arches (8) such that the interior (6) of the filter element has a constriction (11) in the area of the concave arch (9), said constriction (11) being adjoined by two wide zones (12) of the interior of the filter element.