Washing Machine Rinse Control Using Detergent Conductivity
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Solution Overview
Problem
Conventional washing machines have long intermediate spin cycles at high speeds, leading to wear and creasing of linen, noise pollution, and inefficient water extraction, which can be improved by adapting washing process parameters based on detergent type and quantity.
Innovation Solution
A servo-control method that determines the type and quantity of detergent by measuring conductivity, adjusting intermediate spin time and drum speed, and optimizing the number and duration of rinsing phases to minimize mechanical stress and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If long intermediate spin cycles at high speed are used, then water extraction efficiency is improved, but mechanical stress on linen increases causing wear and creasing
Solution Approach 1:
The patent applies dynamics by making the spin cycle parameters (duration and speed) adjustable and adaptive rather than fixed. The control unit modifies these parameters based on detected detergent characteristics, allowing the system to optimize between water extraction efficiency and mechanical stress on different fabric types.
Solution Approach 2:
The patent changes physical parameters of the spin cycle (time and rotational speed) based on detected detergent properties. By measuring conductivity to identify detergent type and concentration, the system adjusts spin parameters to match the specific washing conditions, resolving the contradiction between extraction efficiency and fabric protection.
2Productivity
If long intermediate spin cycles at high speed are used, then water extraction efficiency is improved, but noise pollution increases
Solution Approach 1:
The system dynamically adjusts spin cycle duration and speed based on detergent detection, allowing optimization of noise levels while maintaining adequate water extraction. The control unit can reduce speed or time when appropriate, balancing productivity with noise reduction.
Solution Approach 2:
By changing spin parameters (time and speed) according to detergent characteristics, the system can reduce noise-generating high-speed operation while still achieving sufficient water extraction, thus resolving the contradiction between productivity and noise pollution.
3Ease of operation
If fixed washing programs are used, then ease of operation is improved, but adaptability to different detergent types deteriorates
Solution Approach 1:
The system performs self-service by automatically detecting detergent type and concentration through conductivity measurement, then autonomously adjusting washing parameters without user input. This maintains ease of operation while achieving high adaptability to different detergent conditions.
Solution Approach 2:
The system uses feedback from conductivity sensors to detect detergent characteristics and automatically adjusts washing program parameters. This closed-loop control enables the machine to adapt to different detergents while keeping the user interface simple and easy to operate.
4Device complexity
If conventional fixed-duration rinsing phases are used, then device complexity is minimized, but rinsing efficiency deteriorates
Solution Approach 1:
The system uses conductivity measurement feedback during rinsing phases to detect when detergent has been sufficiently removed from fabrics. This allows automatic termination of rinsing when effective, improving rinsing efficiency without significantly increasing device complexity since it uses existing sensors and control units.
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 optimizes the washing process by reducing mechanical stress on linen, minimizing noise, and enhancing rinsing efficiency while lowering water and energy consumption.
Implementation Method 1
a step of measuring the conductivity of a laundry bath
Data Source
Figure 1~3
Figure 2
AI summary
The procedure, for use on an automatic washing machine or washer/drier taking 2 - 4 kg of washing and a quick- or slow-dissolving liquid or powdered detergent in block or loose form, includes periodic measurement of the electrical conductivity of the rinsing water. The measured values are compared with pre-determined threshold levels, and the duration of the rinsing and spin cycles of the washing programme are adjusted to ensure that the use of rinsing water and intermediate spin speeds are kept to a minimum.