Dishwasher Detergent Dissolution Sensing for Adaptive Wash Control
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Solution Overview
Problem
Existing dishwasher technologies cannot differentiate between detergents of similar chemical composition but different physical forms, such as powder and tablet, leading to suboptimal washing program adjustments.
Innovation Solution
A method using a conductivity sensor to measure the rate of detergent dissolution, allowing for differentiation between fast and slow dissolving detergents, and adjusting washing program parameters accordingly, including pre-wash phase duration, temperature, and water circulation speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conductivity sensor is used to measure detergent concentration, then the detergent supply can be maintained at a constant level, but the system cannot differentiate between detergents of similar chemical composition but different physical forms (powder vs. tablet)
Solution Approach 1:
The system performs preliminary measurements of conductivity at multiple time points during the pre-wash phase, before the main wash begins. By analyzing the rate of change of conductivity during this preliminary period, the system can determine whether the detergent is in powder or tablet form and adjust the washing program accordingly.
Solution Approach 2:
The system continuously monitors conductivity changes and uses this feedback to determine detergent dissolution rate. The measured conductivity values are fed back to the control unit, which compares the rate of change against predetermined thresholds to identify detergent form and automatically adjusts washing parameters such as water circulation speed, temperature, and program duration.
2Productivity
If the washing program is optimized for fast-dissolving powder detergent, then cleaning efficiency is improved, but slow-dissolving tablet detergent does not dissolve completely leading to poor cleaning results
Solution Approach 1:
The washing program is made dynamic and adaptive based on detected detergent form. For powder detergent, the system uses higher water circulation speeds and shorter pre-wash durations to maintain high productivity. For tablet detergent, the system automatically reduces water circulation speed and extends pre-wash duration to ensure complete dissolution, thereby maintaining reliability across different detergent types.
Solution Approach 2:
The system changes key washing parameters including water circulation speed, temperature profile, and program duration based on the detected detergent form. When tablet detergent is detected, the water circulation speed is reduced and pre-wash time is extended to allow complete dissolution. When powder detergent is detected, the system uses faster circulation and shorter times to optimize cleaning efficiency.
3Use of energy by moving object
If water circulation speed is increased to accelerate detergent dissolution, then detergent activation is improved, but energy consumption increases
Solution Approach 1:
The system applies partial action by using reduced water circulation speeds only when tablet detergent is detected and complete dissolution is required. For powder detergent where complete dissolution is less critical, the system uses normal circulation speeds, thereby avoiding unnecessary energy consumption while still achieving adequate detergent activation.
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 optimal detergent usage and cleaning efficiency by tailoring the washing program to the specific detergent form, ensuring effective activation and prolonged detergent effectiveness.
Implementation Method 1
a conductivity sensor which detects a change in conductivity of the cleaning liquid upon addition of a detergent to the cleaning liquid
Data Source
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AI summary
A method to operate a dishwasher, comprising: 1. adding detergent to a cleaning liquid which is circulated within the dishwasher; 2. measuring the conductivity of the cleaning liquid and determining the rate of change in conductivity caused by dissolution of the detergent in the cleaning liquid; 3. comparing the rate of change in conductivity with a predetermined threshold value so as to determine the dissolution rate of the detergent that has been added in step (A) to the cleaning liquid; and 4. adjusting operating parameters based on the determination of step (C).