Dust Extractor Pre-Filter Valve for Reverse Flow Cleaning

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Solution Overview

Problem

Existing industrial dust extractors face inefficiencies in maintaining dust extraction efficiency due to filter clogging, as the pre-filters accumulate particulate matter, leading to decreased airflow and reduced performance.

Innovation Solution

A pre-filter arrangement with a filter side wall that tapers inwardly towards the center, forming separate chambers, and a valve mechanism that generates a reverse flow of air to dislodge particles, combined with a rotation guide to ensure correct installation and a control unit for automated cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the pre-filter accumulates particulate matter to capture dust, then dust extraction efficiency is improved, but airflow is obstructed leading to decreased performance

Engineering Contradiction:
Improvedust extraction efficiencyVSAvoidairflow
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The system performs preliminary filter cleaning by reversing airflow through the pre-filter at scheduled intervals or when clogging is detected, removing accumulated particulate matter before it significantly obstructs airflow. This preliminary maintenance action prevents the contradiction from fully manifesting by periodically restoring airflow while preserving the dust capture function.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The filter cleaning operation is implemented as a periodic process, alternating between normal dust extraction mode and reverse-flow cleaning mode. During normal operation, the filter captures dust; during periodic cleaning intervals, airflow is reversed to dislodge and remove accumulated particles, thereby周期ically restoring airflow without continuous performance loss.

Inventive Principle:
Principle #19Periodic action

2Ease of operation

If the filter is cleaned by reversing air flow, then dust is removed from the filter, but the cleaning process disrupts the extraction process

Engineering Contradiction:
Improvefilter cleaningVSAvoiddust extraction continuity
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The filter assembly is divided into multiple segments or chambers, allowing one section to be cleaned while other sections continue normal dust extraction operations. This segmentation enables the cleaning function to be performed on a portion of the filter without completely interrupting the overall dust extraction process, maintaining partial productivity during maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system maintains continuous dust extraction capability during filter cleaning by using multiple filter chambers in parallel or by designing the reverse-flow cleaning to occur in a manner that preserves overall airflow through the system. The useful action of dust extraction continues uninterrupted or with minimal interruption while cleaning operations are performed on specific filter sections.

Inventive Principle:
Principle #20Continuity of useful action

3Device complexity

If a single pre-filter chamber is used, then the device structure is simple, but the filter must be completely stopped for cleaning

Engineering Contradiction:
Improvefilter structureVSAvoidextraction interruption
Core Design Contradiction:
Device complexityVSLoss of time

Solution Approach 1:

The pre-filter is divided into multiple independent chambers or sections, each capable of being cleaned separately. This segmentation allows the filter system to maintain operational complexity only slightly higher than a single chamber, while enabling continuous operation during cleaning by isolating and cleaning individual chambers without shutting down the entire extraction system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system performs preliminary cleaning operations on individual filter chambers before they become fully clogged, using reverse airflow to dislodge particles. This preliminary maintenance approach, combined with multi-chamber design, reduces the frequency and duration of complete system shutdowns by addressing filter clogging proactively in isolated sections.

Inventive Principle:
Principle #10Preliminary action

4Ease of manufacture

If the filter side wall is vertical, then manufacturing is simple, but gravitational pull does not help dislodge particles during cleaning

Engineering Contradiction:
Improveside wall constructionVSAvoidparticle dislodgement efficiency
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The filter side wall is designed with an asymmetric tapered geometry rather than a simple vertical cylinder. The tapered shape, while requiring slightly more complex manufacturing, creates an asymmetric profile that works in conjunction with reverse airflow to efficiently dislodge particles. The asymmetric design optimizes the balance between manufacturing feasibility and cleaning effectiveness by leveraging gravitational and aerodynamic forces.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The side wall geometry parameter is changed from vertical to tapered, modifying the angle and profile to optimize particle dislodgement. This parameter change enhances the cleaning operation by creating a surface profile that, when combined with reverse airflow, more effectively removes accumulated particulate matter while remaining manufacturable using standard forming processes.

Inventive Principle:
Principle #35Parameter changes

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 solution enhances filter cleaning efficiency, maintains airflow during cleaning, and prevents incorrect installation, prolonging the operational time of the dust extractor by regularly cleaning the pre-filters without disrupting the extraction process.

Implementation Method 1

gravitational pull helps to dislodge particles from the filter side wall during filter cleaning using a reverse thrust of air

Methodology Applied
Scientific EffectGravitational pull: Gravitation

Implementation Method 2

a valve arrangement configured to generate a reverse flow of air, preferably a pulse of air, to clean a pre-filter

Methodology Applied
Scientific EffectReverse flow of air: Fluid Spray

Data Source

PatentEP4711082A2Pre-filter arrangements and valves for an industrial dust extractor
Publication Date: 2026.03.18 HUSQVARNA AB
  • EP4711082A2 patent drawingFigure 1A~1B
  • EP4711082A2 patent drawingFigure 2A~2F
  • EP4711082A2 patent drawingFigure 3A~4

AI summary

A valve arrangement (400) configured to generate a reverse flow of air to clean a pre-filter (200) for a heavy-duty dust extractor (100), the arrangement comprising: a main valve closure body (410) arranged to move between a first position (420) and a second position (430), where, in the first position (420), the main valve closure body (410) is arranged to seal a passage (440) between an ambient pressure (P2) side and a low pressure (P3) side of the valve arrangement (400), where, in the second position (430), the main valve closure body (410) is arranged to seal a passage (450) between the low pressure (P3) side of the valve arrangement (400) and a suction conduit (140, P4), the valve arrangement (400) further comprising: a control body (460), connected to the main valve closure body (410), such that a position of the main valve closure body (410) is determined by a position of the control body (460), a control chamber (461), partially defined by the control body (460), whereby a volume of the control chamber (461) is variable in relation to the position of the control body (460), and a control chamber valve (462) having an open state and a closed state for regulating a pressure (P1) in the control chamber, wherein the state of the control chamber valve (462) is determined by a trigger device (470, 480).