Washing Machine Load Sizing by Water Level Saturation

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Solution Overview

Problem

Existing washing machines face challenges in accurately determining laundry load size without increasing costs by relying on motor sensors and advanced motor control systems, often leading to inefficient water usage and wash performance due to user errors in manual input.

Innovation Solution

A method that uses a water level sensor and water flow sensor to supply water to preset levels, determining load size by measuring the amount of water absorbed and displaced, effectively saturating the laundry load to minimize errors from absorbency and residual water, and adjusting water levels to optimize wash performance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If motor sensors and advanced motor control systems are used to automatically determine load size, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:

Improveload size determination accuracyVSAvoidmotor sensors and control systems

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent extracts the load size determination function from the motor control system and relocates it to the water level sensing system. By measuring water levels at different stages (before and after saturation), the system determines load size without requiring additional motor sensors or complex motor control electronics, thus reducing device complexity while maintaining measurement precision

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The water level sensor is given a dual function: it continues to perform its traditional water level monitoring role while also serving as the primary sensor for load size determination. This multi-functionality eliminates the need for dedicated motor sensors and reduces overall system complexity

Inventive Principle:

Principle #6Universality (Multi-functionality)

2Device complexity

If user manually inputs fabric load information, then device complexity is reduced, but measurement precision deteriorates due to user errors

Engineering Contradiction:

Improvemanual input systemVSAvoidload size accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The washing machine performs self-measurement of load size through automated water level sensing during the saturation process. The system independently determines load characteristics without relying on user input, eliminating user errors while keeping the device simple and cost-effective

Inventive Principle:

Principle #25Self-service

3Device complexity

If water level is set based on first amount of water, then wash process is simplified, but measurement precision deteriorates due to errors from absorbency and residual water

Engineering Contradiction:

Improvewater level controlVSAvoidload size determination

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The system performs a preliminary saturation action by continuing to fill water beyond the initial level until the laundry load is fully saturated. This preliminary action ensures that all absorbency variations and residual water effects are accounted for before the final load size determination, improving measurement precision

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The patent replaces direct mechanical measurement of load characteristics with an indirect measurement approach using water level sensing. By measuring the relationship between water volume added and water level rise, the system indirectly determines load size with higher precision, overcoming the limitations of direct mechanical methods

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 allows for accurate determination of laundry load size without additional costly hardware, ensuring optimal water usage and wash performance by accounting for errors in absorbency and residual water, thus improving user convenience and machine efficiency.

Implementation Method 1

a water level sensor and water flow sensor are supplied to a tub

Methodology Applied

Scientific EffectHydrostatic pressure: Pressure Gradient

Implementation Method 2

a water level sensor and water flow sensor are supplied to a tub

Methodology Applied

Scientific EffectFluid flow detection: Flow Separation

Implementation Method 3

supplying water from the reference water level to a second water level above the reference water level and sufficient to submerge the laundry load

Methodology Applied

Scientific EffectAbsorption: Absorption (physical)

Data Source

PatentUS8245342B2Method for determining load size in a washing machine

Publication Date: 2012.08.21 WHIRLPOOL CORP

AI summary

A method for determining the laundry load size according to one embodiment of the invention in an automatic clothes washer comprising supplying water to a reference water level to define a first amount of water, supplying water from the reference water level to a second water level above the reference water level and sufficient to submerge the laundry load to define a second amount of water, and determining a load size for the laundry load based on the second amount of water such that errors associated with the first amount of water are not considered in the load size determination based on the second amount of water.