Apparatus for cleaning a surface

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Solution Overview

Problem

Existing surface cleaning apparatuses face challenges in preventing overfill conditions in recovery tanks, which can lead to fluid or foam leakage and damage to internal components, and fail to accurately detect liquid and foam levels without mechanical floats, potentially causing operational issues.

Innovation Solution

The apparatus incorporates a 'floatless' sensing system with electronic liquid level sensing, including high frequency fluid and foam sensors, conductivity sensing, and self-capacitive sensing systems to detect liquid and foam levels, preventing overfill conditions by shutting off suction when predetermined levels are reached, and allowing for accurate fluid management without mechanical floats.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If mechanical floats are used to detect liquid levels, then liquid level detection can be achieved, but the device complexity increases and reliability decreases due to mechanical wear and potential failure

Engineering Contradiction:
Improveliquid level detection reliabilityVSAvoidsensing system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent replaces mechanical float systems with electronic sensing systems including capacitive sensors, conductive sensors, and high-frequency sensors. These electronic systems detect liquid levels without moving parts, eliminating mechanical wear and failure modes while providing more reliable and maintenance-free operation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces electronic fields (capacitive, conductive, high-frequency electromagnetic fields) as intermediaries to detect liquid levels. These fields interact with the liquid to provide detection signals without requiring direct mechanical contact or floating components, thereby improving reliability while maintaining detection accuracy.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If no liquid level sensing system is used, then the device complexity is reduced, but overfill conditions occur leading to fluid leakage and damage to internal components

Engineering Contradiction:
Improveprotection against overfill damageVSAvoidsensing and control system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements liquid level sensing that detects approaching critical levels before overfill conditions occur. The system provides advance warning and can automatically shut off liquid supply or activate pumping systems in advance, preventing overfill damage before it happens rather than responding after the problem occurs.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent employs feedback control systems where sensor outputs are continuously monitored and fed back to control mechanisms. When liquid levels approach critical thresholds, the feedback loop automatically triggers shutdown valves, pumps, or alarms to prevent overfill conditions, thereby protecting the system without requiring complex manual monitoring.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple sensing systems are implemented to accurately detect both liquid and foam levels, then measurement precision is improved, but device complexity increases

Engineering Contradiction:
Improveliquid and foam level detection precisionVSAvoidmultiple sensing systems complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent employs multi-functional sensing systems where a single sensor or sensor array can detect both liquid levels and foam levels, or where the same sensing technology (such as capacitive or high-frequency sensors) serves multiple detection purposes. This reduces the number of separate sensing systems needed while maintaining measurement precision for different substances.

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

Solution Approach 2:

The patent utilizes different physical parameters (capacitance, conductivity, high-frequency electromagnetic properties) to distinguish between liquid and foam detection. By changing the measurement parameter rather than adding separate mechanical sensing systems, the patent achieves precise differentiation between liquid and foam levels while minimizing system complexity.

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 effectively prevents overfill conditions, reduces the risk of leakage and damage, and provides accurate detection of liquid and foam levels, ensuring efficient and reliable operation of the surface cleaning apparatus.

Implementation Method 1

high frequency fluid and foam sensors

Methodology Applied
Scientific EffectHigh frequency sensing:

Implementation Method 2

conductivity sensing

Methodology Applied
Scientific EffectConductivity sensing: Conduction (electrical)

Implementation Method 3

self-capacitive sensing systems

Methodology Applied
Scientific EffectCapacitance sensing: Capacitance

Data Source

PatentEP3787468B1Apparatus for cleaning a surface
Publication Date: 2024.06.19 BISSELL INC
  • EP3787468B1 patent drawingFigure 1
  • EP3787468B1 patent drawingFigure 2
  • EP3787468B1 patent drawingFigure 3

AI summary

An apparatus (10) for cleaning a surface includes a liquid delivery system (12) for storing cleaning liquid and delivering the cleaning liquid to the surface to be cleaned, a fluid recovery system (14) and a control system. The control system includes a controller (122) that is coupled to a fluid level sensing assembly (98). Methods of operating the same include sensing foam or liquid with the fluid level sensing assembly (98).