Demand-based filter cleaning

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Solution Overview

Problem

Conventional vacuum cleaners perform filter cleaning at fixed intervals, ignoring the filter's contamination state, leading to inefficient suction power and potential damage due to unsuitable cleaning times, which causes pressure surges and dust clouds.

Innovation Solution

A method to adjust the intensity of filter cleaning pulses based on the filter's state, varying pulse length and number, using sensor data to optimize cleaning processes and minimize pressure surges, ensuring adaptive and needs-based cleaning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If filter cleaning is performed at fixed intervals regardless of filter condition, then the filter will be cleaned regularly, but cleaning efficiency decreases and unnecessary cleaning occurs

Engineering Contradiction:
Improvefilter cleaning reliabilityVSAvoidcleaning efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent applies dynamics by transitioning from fixed-interval cleaning to adaptive cleaning that responds to real-time filter conditions. The control unit dynamically adjusts cleaning timing based on sensor feedback about filter soiling levels, allowing the system to optimize cleaning operations according to actual needs rather than following a rigid schedule.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements feedback mechanisms where sensors continuously monitor filter condition parameters (such as pressure differential or visual soiling indicators) and feed this information back to the control unit. This closed-loop feedback enables the system to make informed decisions about when cleaning is actually needed, preventing both premature and delayed cleaning operations.

Inventive Principle:
Principle #23Feedback

2Manufacturing precision

If cleaning pulse intensity is increased to improve cleaning effectiveness, then filter cleaning quality improves, but pressure surges increase causing dust clouds

Engineering Contradiction:
Improvefilter cleaning qualityVSAvoiddust cloud generation
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent applies parameter changes by dynamically adjusting cleaning pulse parameters (duration, intensity, frequency) based on the measured filter condition. Rather than using fixed high-intensity pulses that cause dust clouds, the system modifies pulse parameters to match the actual soiling level, achieving effective cleaning with minimal disturbance to the dust collection process.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements partial action by applying cleaning pulses only to the extent necessary based on filter condition assessment. Instead of always applying maximum cleaning intensity, the system uses just enough cleaning energy to restore filter performance, avoiding excessive action that would generate harmful dust clouds while still achieving sufficient cleaning quality.

Inventive Principle:
Principle #16Partial or excessive action

3Reliability

If cleaning pulses are performed frequently to maintain filter performance, then suction performance is maintained, but negative pressure reduction occurs interrupting dust collection

Engineering Contradiction:
Improvesuction performanceVSAvoiddust collection efficiency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The control unit uses feedback from filter condition sensors to determine when cleaning is truly necessary. By monitoring parameters such as pressure differential across the filter, the system can identify the optimal cleaning moment, avoiding unnecessary cleaning operations that would interrupt dust collection and maintain suction performance only when actually needed.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary assessment of filter condition through sensor monitoring before initiating cleaning. This preliminary action allows the system to predict when cleaning will be needed and schedule it optimally, preventing both premature cleaning that would interrupt dust collection and delayed cleaning that would degrade suction performance.

Inventive Principle:
Principle #10Preliminary action

4Productivity

If filter cleaning is delayed to minimize interruptions, then dust collection efficiency is maintained, but filter becomes heavily clogged potentially damaging the turbine

Engineering Contradiction:
Improvedust collection efficiencyVSAvoidturbine protection
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

Continuous sensor monitoring provides feedback on filter soiling progression, allowing the control unit to detect when cleaning is approaching the critical threshold. This real-time feedback enables the system to schedule cleaning just in time to prevent turbine damage while minimizing interruptions to dust collection operations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system performs preliminary monitoring and assessment of filter condition to predict when cleaning will be necessary. By taking preliminary action through continuous condition assessment, the system can plan cleaning operations in advance to prevent heavy clogging and potential turbine damage while optimizing the timing to minimize dust collection interruptions.

Inventive Principle:
Principle #10Preliminary action

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 approach reduces unnecessary cleaning, maintains suction efficiency, and minimizes dust clouds by customizing cleaning intensity according to the filter's condition, preventing re-contamination and protecting the user from dust exposure.

Implementation Method 1

The backflushing is based on a pressure gradient that builds up across the filter during normal operation. The sudden actuation of a flap and/or opening in an air line of the vacuum in the area of the suction turbine causes a brief reversal of the airflow direction through the filter during cleaning.

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Data Source

PatentEP4125523B1Demand-based filter cleaning
Publication Date: 2024.07.10 HILTI AG
  • EP4125523B1 patent drawingFigure 1

AI summary

The present invention relates to a method for controlling a filter cleaning process in a vacuum cleaning apparatus, the vacuum cleaning apparatus comprising at least one filter which is cleaned regularly, and the filter cleaning process comprising cleaning operations with individual cleaning pulses. A basic concept on which the proposed method is based consists in being able to set an intensity of the cleaning operations according to a state of the filter of the vacuum cleaning apparatus. This can be achieved, for example, by a variable chronological length of a cleaning pulse and/or a variable number of cleaning pulses per cleaning operation. In particular, the proposed method allows particularly efficient filter cleaning according to need, during which the soiling state and/or ageing of the filter in the vacuum cleaning apparatus can be taken into account. In a second aspect, the invention relates to a vacuum cleaning apparatus by means of which the proposed method can be carried out. To this end, the vacuum cleaning apparatus can comprise, for example, a suitable sensor system for sensing the state of the filter, and a control device.