Washing Machine Detergent Metering for Variable Water Hardness
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Solution Overview
Problem
Washing machines struggle to optimize cleansing agent metering based on water hardness, leading to reduced effectiveness and potential staining issues, as well as unnecessary use of water-softening additives due to varying water hardness conditions.
Innovation Solution
A washing machine equipped with a water hardness sensor and a programming device that adjusts the cleansing agent pump's operation to match the water hardness, allowing for optimal cleansing agent metering and eliminating the need for water-softening additives by mixing softened and untreated water and controlling the cleansing agent supply accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the metered amount of cleansing agent is increased to compensate for hard water, then washing effectiveness is improved, but excess cleansing agent causes light-coloured stains on dark garments and financial waste
Solution Approach 1:
The patent implements a dynamic metering system that automatically adjusts the amount of cleansing agent based on real-time water hardness measurements. The programming device receives hardness values from the sensor and modulates the pump operation accordingly, transitioning from static fixed-dose metering to dynamic adaptive metering that optimizes washing effectiveness while preventing stains.
Solution Approach 2:
The system establishes a feedback loop where the water hardness sensor continuously monitors water quality, transmits data to the programming device, which then adjusts the cleansing agent metering in response. This closed-loop control ensures the metered amount always matches the actual water hardness condition, eliminating both understreatment and over-treatment scenarios.
2Device complexity
If a fixed metered amount of cleansing agent is used regardless of water hardness, then the device complexity is reduced, but washing effectiveness varies with water hardness conditions
Solution Approach 1:
The system enables the washing machine to automatically sense and adapt to water hardness conditions without user intervention. The sensor and programming device work autonomously to determine the optimal cleansing agent dosage, eliminating the need for users to manually adjust settings or add water-softening additives, thus maintaining simplicity while improving reliability.
Solution Approach 2:
The patent changes the operating parameter of the metering system from a fixed value to a variable value that responds to water hardness measurements. The programming device modifies the metering rate based on the sensor input, allowing the system to adapt to different water conditions while maintaining a relatively simple overall structure.
3Reliability
If water-softening additives are added to the cleansing agent to handle hard water, then washing effectiveness is improved, but the device complexity and cost increase unnecessarily
Solution Approach 1:
The patent extracts the water-softening function from the mechanical/chemical softening systems and replaces it with a sensing and control system that adjusts cleansing agent dosage. Instead of physically softening the water, the system measures hardness and compensates by metering the appropriate amount of cleansing agent, thereby eliminating complex softening hardware while maintaining washing effectiveness.
Solution Approach 2:
The invention replaces mechanical/chemical water softening mechanisms with an electronic sensing and control system. Rather than using ion exchange resins or chemical additives to soften water, the system uses a hardness sensor and programming device to electronically control the metering pump, substituting a simple measurement-and-control approach for complex physical softening systems.
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 solution ensures effective washing performance regardless of water hardness variations, reduces cleansing agent consumption, prevents staining, and eliminates the need for water-softening additives, providing financial and operational advantages.
Implementation Method 1
the ion exchange resins typically used for this purpose tend to become depleted
Implementation Method 2
a pump for the metered feed of the cleansing agent into the chamber
Data Source
Figure 1
Figure 2
AI summary
The washing machine comprises: a washing chamber (10); a conduit (12) feeding water into said washing chamber (10); a pump (22) for metering the quantity of cleansing agent fed into the washing chamber (10); a hardness sensor (16) for water fed into the washing chamber (10); and means (24) controlling the pump (22) as a function of the water hardness degree sensed by the sensor (16).