Back-flushable air filter

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Solution Overview

Problem

Existing vacuum cleaners with backwashable air filters require manual switching of valve blocks or separate valve units to change flow direction, which is inconvenient and may lead to damage from suction air flow during backwash operations.

Innovation Solution

A valve element with a non-return valve that automatically closes the clean air outlet and opens a secondary air inlet path, allowing ambient air for backwashing without the need for a compressor or manual switching, and separates the suction fan from the air filter during backwash, preventing damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If manual switching of valve blocks is used to change flow direction, then the air filter can be backwashed, but the operation becomes inconvenient and complex

Engineering Contradiction:
Improveease of switching between filter and backwash operationsVSAvoidcomplexity of valve blocks and manual switching mechanism
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The suction fan itself performs the backwashing function by creating negative pressure that automatically draws ambient air through the filter element in reverse direction, eliminating the need for separate valve blocks and manual switching. The system uses its own suction capability to clean the filter.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The complex valve switching mechanism is completely removed from the system. Instead of using valve blocks to redirect airflow, the invention extracts the switching function entirely and relies on the natural flow direction changes created by the suction fan during different operational phases.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If separate valve units are used to control flow direction, then the air filter can be backwashed, but the device complexity increases

Engineering Contradiction:
Improvereliability of backwash operationVSAvoidcomplexity of separate valve units
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The control of airflow direction for both filter operation and backwash operation is merged into a single mechanism - the suction fan. The same component that drives filtration also enables backwashing by creating negative pressure, eliminating the need for separate valve units and reducing overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The suction fan serves multiple functions: it drives the filtration process during normal operation and simultaneously enables backwashing by creating negative pressure when the filter becomes clogged. This multi-functionality eliminates the need for dedicated backwash valves or separate control mechanisms.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of operation

If the suction fan is connected to the air filter during backwash operation, then the suction fan may rotate and cause damage to electronics

Engineering Contradiction:
Improveease of backwash operationVSAvoiddamage risk to suction fan and electronics
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The suction fan is completely disconnected from the air filter housing during backwash operation. By extracting the fan from the housing structure, the system prevents any possibility of the fan rotating during backwashing, thereby eliminating the risk of damage to the fan and associated electronics.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A removable housing structure acts as an intermediary between the suction fan and the air filter. During backwash operation, the housing can be removed or opened, physically separating the fan from the filter assembly and preventing unintended fan rotation while still allowing backwash airflow through the filter element.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables easy and automatic switching between filter and backwash operations, ensuring the air filter can be cleaned without damaging the electronics and maintaining suction power by using ambient air for cleaning, thus extending the filter's lifespan and ensuring continuous operation.

Implementation Method 1

the valve element has a non-return valve which is arranged and designed in such a way that it closes the clean air area when an air flow flows through the air filter by means of an air flow flowing from the clean air area in the direction of the dust air area

Methodology Applied
Scientific EffectNon-return valve mechanism: Valve

Implementation Method 2

The ambient air required for the backwash operation is sucked into the air filter through the secondary air inlet path

Methodology Applied
Scientific EffectSuction: Suction

Data Source

PatentEP2979602B1Back-flushable air filter
Publication Date: 2020.02.12 VORWERK & CO INTERHOLDING GMBH
  • EP2979602B1 patent drawingFigure 1
  • EP2979602B1 patent drawingFigure 2
  • EP2979602B1 patent drawingFigure 3

AI summary

The invention relates to an air filter (2) that can be backwashed, in particular for a vacuum cleaner, with a filter element (3) separating a dust air space (8) from a clean air space (4) and which, in filter operation, removes air to be cleaned from the direction of the dust air space (8) into Is flowed through in the direction of the clean air space (4), the clean air space (4) being assigned a clean air outlet region (5). In order to create an air filter that can be backwashed, which can be backwashed independently of a special design of the device in which it is used and is therefore compatible with a large number of devices, it is proposed that the clean air outlet area (5) has a valve element (9), which is designed to allow backwashing of the filter element (3) with ambient air in a backwash operation as a result of the opening of a secondary air inlet path (10), which is downstream of the clean air outlet area (5) in the direction of flow for filter operation. The invention also relates to a method for operating an air filter (2) that can be backwashed.