Floor Sweeper Filter Shaking With Variable-Frequency Vibration

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Solution Overview

Problem

Existing floor cleaning and sweeping machines face challenges with filter clogging, leading to high maintenance costs and inefficiencies due to the need for frequent manual cleaning, as mechanical shaking at fixed frequencies only partially removes dust and dirt, especially in intense environments.

Innovation Solution

A filter system with a rotary electric motor and unbalanced masses that varies its rotation speed between two extreme values, generating a broad band of oscillation frequencies to effectively clean the filter plate by matching harmonic stresses with its natural eigenfrequencies, enhancing cleaning efficiency and reducing maintenance needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a filter plate is used in floor cleaning machines, then air filtering is achieved, but the filter plate clogs frequently requiring periodic cleaning

Engineering Contradiction:
Improvefilter operation continuityVSAvoidmachine downtime for filter cleaning
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The patent applies mechanical vibration through an electric motor with unbalanced masses that generates oscillatory motion in the filter plate. This vibration causes dust and dirt particles to detach from the filter surface, enabling automatic cleaning during operation and preventing clogging that would otherwise require machine downtime.

Inventive Principle:
Principle #18Mechanical vibration

Solution Approach 2:

The patent implements periodic cleaning action by operating the vibration motor at intervals during the filter's service life. The motor is activated periodically to shake off accumulated dust, maintaining filter effectiveness without requiring complete shutdowns or frequent manual maintenance interventions.

Inventive Principle:
Principle #19Periodic action

2Productivity

If fixed frequency shaking is applied to clean the filter plate, then some dust removal is achieved, but cleaning effectiveness is limited especially in intense environments

Engineering Contradiction:
Improvefilter cleaning effectivenessVSAvoiddust and dirt accumulation on filter
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The patent changes the frequency parameter of the vibration motor, operating it at variable frequencies including resonant frequencies of the filter plate. This optimization enhances the detachment of dust particles from the filter surface, significantly improving cleaning effectiveness in demanding industrial environments compared to fixed frequency operation.

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 variable frequency shaking action significantly increases the cleaning effectiveness of the filter plate, reducing maintenance requirements and extending the time between filter cleanings, thereby improving the economic value of the machine.

Implementation Method 1

A filter system with a rotary electric motor and unbalanced masses that varies its rotation speed between two extreme values, generating a broad band of oscillation frequencies to effectively clean the filter plate by matching harmonic stresses with its natural eigenfrequencies

Methodology Applied
Scientific EffectMechanical vibration: Vibration

Implementation Method 2

cleaning efficiency is enhanced by matching harmonic stresses with its natural eigenfrequencies

Methodology Applied
Scientific EffectResonance: Resonance

Data Source

PatentEP2119389B1Improved filtering means and floor-sweeping machine provided with such means
Publication Date: 2018.05.30 NILFISK AS
  • EP2119389B1 patent drawingFigure 1
  • EP2119389B1 patent drawingFigure 2
  • EP2119389B1 patent drawingFigure 3

AI summary

Filtering means for filtering out impurities contained in an air stream, and comprising an inner filter plate or sieve, an outer frame that houses said filter plate thereinside, a structure for retaining said filter plate and conveying the shaking motion, a support socle applied on to said structure, a rotary electric motor, whose rotor is provided with one or more unbalanced masses, and which is fixedly mounted on said socle. The invention is based on the fact that said electric motor is operated in an intermittent manner, preferably with a direct-current, substantially square-wave supply voltage according to an ON-OFF cycling pattern, so as to generate a very broad spectrum of shaking frequencies that proves more effective in enabling the filter plate to be freed from the impurities being retained thereupon. The ideal mechanical configuration calls for the structure for retaining the filter plate and conveying the shaking motion to be made up so as to comprise at least two portions projecting freely from the middle region of said structure in opposite directions, as well as for the electric motor to be positioned in a region of symmetry of said structure.