Laundry Detergent Dosing by Water Absorption Load Detection
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Solution Overview
Problem
Conventional washing machines lack the ability to automatically dose detergent based on the laundry load, relying on expensive and complex mass sensors, and often require user input that can be inaccurate.
Innovation Solution
A method for automatically dosing detergent during a washing cycle by recognizing the laundry load through water absorption, adjusting the detergent quantity based on parameters like water hardness, soiling level, and laundry type, without the need for a mass sensor, ensuring optimal detergent distribution and minimizing water usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If mass sensors are used to measure laundry load, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent replaces mechanical mass sensors with a water absorption-based detection system. The control unit measures the volume of water absorbed by the laundry during a recognition phase and converts this to an equivalent mass value, thereby achieving mass measurement without mechanical sensors.
Solution Approach 2:
The patent introduces water as an intermediary medium to indirectly measure laundry mass. Instead of directly weighing the laundry, the system measures how much water the laundry absorbs, using water as a mediator to transfer the measurement information to the control unit.
2Productivity
If detergent is dosed at the start of the wash cycle, then productivity is improved, but detergent distribution accuracy may worsen
Solution Approach 1:
The patent performs preliminary detergent dosing at the start of the wash cycle based on an initial laundry load assessment. The system doses detergent for a partial load first, then adjusts the dosage later after more accurate load recognition is complete, combining early action with subsequent refinement.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit continuously monitors water absorption during the recognition phase, compares it with the initial detergent dosage, and adjusts the detergent quantity accordingly. This closed-loop control ensures accurate distribution even when dosing starts early.
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 accurate and cost-effective automatic detergent dosing, improving washing efficiency and reducing cycle time by introducing detergent early in the cycle, while eliminating the need for expensive mass sensors and user input errors.
Implementation Method 1
The laundry load recognition phase is carried out by means of detecting the mass of laundry based on the level of water absorption by the load of laundry
Data Source
Figure 1
AI summary
A method for dosing detergent (A) into a washing machine, with a tub (2) filled with liquid from a water supply, a rotating drum (3) for the washing and a washing program controller (4), involves (i) dosing and distributing (A), in amount determined for a predetermined partial charge of washing, while introducing water, (ii) recognizing the washing charge and (iii) dosing and distributing further (A) if the charge is more than the predetermined value.