Surface Cleaner Floatless Fluid Level Sensing to Prevent Overfill
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Solution Overview
Problem
Existing surface cleaning apparatuses lack effective fluid level sensing systems to prevent overfill conditions in recovery tanks, which can lead to fluid spillage and damage to internal components.
Innovation Solution
Incorporation of a floatless sensing system with electronic liquid level sensing using multiple probes and a controller to detect fluid and foam levels in the recovery tank, activating shut-off mechanisms to prevent overfill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If no fluid level sensing system is used, then the device complexity is reduced, but fluid spillage and damage to internal components occur due to overfill conditions
Solution Approach 1:
The patent replaces complex mechanical float-based sensing systems with a simpler electrical sensing system using probes and a controller. The electrical system detects fluid levels through conductivity changes, eliminating the need for mechanical moving parts while achieving reliable overfill prevention.
Solution Approach 2:
The sensing system utilizes the inherent electrical properties of the fluid itself (conductivity) to detect its own level. The probes detect when fluid reaches critical levels by measuring electrical conductivity changes, allowing the system to self-monitor without external intervention or complex mechanical structures.
2Measurement precision
If a floatless sensing system with multiple probes is used, then the measurement precision of fluid level is improved, but the device complexity increases due to electronic components
Solution Approach 1:
The sensing system is divided into multiple discrete probes positioned at different heights within the recovery tank. Each probe independently detects fluid level at its specific position, providing segmented measurement points that collectively offer precise overall level detection without requiring a single complex sensor.
Solution Approach 2:
The electrical probes serve multiple functions: they detect both fluid presence and foam presence, monitor liquid levels, and provide shutdown signals. This multi-functionality reduces the need for separate sensing mechanisms, thereby reducing overall device complexity while maintaining high measurement precision.
3Reliability
If electronic liquid level sensing is implemented, then the reliability of preventing fluid ingress is improved, but the ease of manufacture decreases due to electronic assembly requirements
Solution Approach 1:
The patent employs simple, inexpensive electrical probes that can be easily manufactured and replaced if needed. These basic electrical components are far simpler and cheaper to manufacture than complex mechanical sensing assemblies, improving ease of manufacture while maintaining reliable fluid level detection and protection functionality.
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
Prevents fluid or foam ingress into the suction source, protecting internal components and maintaining machine functionality by accurately detecting and responding to tank fill levels.
Implementation Method 1
a fluid level sensing assembly, including at least one probe and a controller communicatively coupled to the at least one probe and configured to electronically control the at least one probe and configured to detect a level of fluid in at least one of the fluid supply tank or the recovery tank
Data Source
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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).