Washing Temperature Control for High-Load Laundry Uniformity
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Solution Overview
Problem
Current washing machines often result in a temperature gradient between laundry and washing liquid, leading to inadequate washing temperatures, especially at high loads, which impairs washing performance and necessitates extended washing times to achieve sufficient bleach activation.
Innovation Solution
A method where item-specific and appliance-specific parameters are recorded to control the heating of the washing liquid, allowing for adaptive washing temperature settings and energy input management through a programmed controller, utilizing an expert system to optimize heating phases and temperature peaks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the washing liquid is heated to a high temperature to ensure sufficient bleach activation and washing performance, then the washing performance is improved, but the temperature gradient between the lye and the laundry increases, causing the average laundry temperature to remain below the required minimum values
Solution Approach 1:
The patent applies periodic heating action by alternating between heating phases and drum rotation phases. The heater is activated in intervals rather than continuously, allowing the drum to redistribute the laundry and equalize temperatures between batches during non-heating periods. This periodic approach prevents excessive temperature gradients while maintaining adequate washing temperature through repeated heating cycles.
Solution Approach 2:
The patent implements dynamic control of the heating process by continuously monitoring the temperature difference between the lye and the laundry. The heating power and duration are adjusted in real-time based on measured temperature gradients, fabric types, and load characteristics. This dynamic adaptation allows the system to maintain optimal washing temperature while minimizing temperature uniformity issues.
2Temperature
If the washing time is extended to allow adequate heating of the laundry and achieve sufficient washing temperature, then the washing performance is improved, but the total washing time increases significantly
Solution Approach 1:
The patent applies preliminary action by pre-heating the washing liquid to the target temperature before the laundry is fully saturated. The system anticipates the thermal mass of the laundry and begins heating the lye in advance, then uses drum rotation to distribute the pre-heated lye throughout the load. This eliminates the need for extended heating time while ensuring the laundry reaches adequate washing temperature.
Solution Approach 2:
The patent maintains continuous useful action by overlapping heating phases with drum rotation phases. Rather than sequential operations, the system continuously alternates between heating the lye and redistributing it through drum motion. This continuous cycle ensures that heating is always occurring while simultaneously working to distribute heat throughout the laundry, reducing total washing time while maintaining temperature uniformity.
3Productivity
If the heating is controlled predominantly continuously to reach the target temperature quickly, then the heating efficiency is improved, but the temperature gradient between the lye and the laundry increases significantly
Solution Approach 1:
The patent segments the continuous heating process into discrete heating intervals separated by drum rotation phases. Instead of one long continuous heating period, the heating is divided into multiple shorter segments throughout the wash cycle. Each segment heats the lye partially, then the drum redistributes the heat, preventing excessive temperature gradients while maintaining overall heating efficiency through cumulative heating effect.
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 reduces wash time while ensuring improved washing performance and uniformity, even with high loads, by precisely controlling the washing temperature and energy input, maintaining effective bleach activation without prolonging the wash cycle.
Implementation Method 1
a heater for heating the washing liquid to a washing temperature
Implementation Method 2
a radiator is usually arranged in the lower part of the tub. The lye is heated by the radiator. As the drum moves, other items of laundry come into contact with the heated suds. The laundry is heated by the exchange between the free and the bound liquor.
Data Source
AI summary
The invention relates to a method for washing laundry in a program-controlled domestic appliance for doing laundry. According to said method, the washing liquid present in the tub is heated and a washing temperature is adjusted, parameter values that are specific of the laundry and/or of the appliance being determined and the heating of the washing liquid to adjust a specific washing temperature being carried out according to the parameter values. The invention also relates to a corresponding domestic appliance.