Automatic Detergent Dosing With Concentration Feedback in Washing Machines
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Solution Overview
Problem
Laundry washing machines with automatic detergent dosing systems often dispense a predetermined dose of detergent regardless of its concentration, leading to overdosing of concentrated or super-concentrated detergents, which affects rinsing performance, causes skin irritation, increases water and energy consumption, and raises laundry costs.
Innovation Solution
A method that uses a concentration sensor and recirculation circuit to detect detergent concentration and adjust the dosage during the washing cycle, ensuring the correct amount of detergent is used based on the type and concentration, thereby optimizing the washing process and reducing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a predetermined dose of detergent is dispensed at any washing cycle, then the dosing process is simple and fast, but the detergent concentration cannot be adapted leading to overdosing of concentrated detergents
Solution Approach 1:
The system performs preliminary actions by introducing a first quantity of water and a first quantity of detergent into the tub before the main washing phase, creating a preliminary solution that allows subsequent concentration measurement and dosage adjustment based on the actual detergent concentration
Solution Approach 2:
The system introduces feedback by measuring the concentration of the detergent solution using a concentration sensor after the preliminary mixing phase, then using this measured concentration value to determine the second quantity of detergent to be added, ensuring the total dosage is optimized according to the actual detergent concentration
2Device complexity
If the same predetermined dose of detergent is used for all detergent types, then the dosing mechanism is simple, but concentrated detergents are overdosed causing skin irritation and excessive foam
Solution Approach 1:
The system performs preliminary actions by introducing a first quantity of water and a first quantity of detergent into the tub before the main washing phase, creating a preliminary solution that allows subsequent concentration measurement and dosage adjustment based on the actual detergent concentration
Solution Approach 2:
The system introduces feedback by measuring the concentration of the detergent solution using a concentration sensor after the preliminary mixing phase, then using this measured concentration value to determine the second quantity of detergent to be added, ensuring the total dosage is optimized according to the actual detergent concentration
3Productivity
If a fixed detergent dosage is applied, then the washing cycle is efficient and fast, but excessive detergent remains in laundry requiring additional rinsing cycles that consume more water and energy
Solution Approach 1:
The system performs preliminary actions by introducing a first quantity of water and a first quantity of detergent into the tub before the main washing phase, creating a preliminary solution that allows subsequent concentration measurement and dosage adjustment based on the actual detergent concentration
Solution Approach 2:
The system introduces feedback by measuring the concentration of the detergent solution using a concentration sensor after the preliminary mixing phase, then using this measured concentration value to determine the second quantity of detergent to be added, ensuring the total dosage is optimized according to the actual detergent concentration
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 ensures accurate detergent dosing, maintains the duration and efficiency of the rinsing phase, reduces water and energy consumption, and saves on detergent refilling costs by preventing overdosing.
Implementation Method 1
a concentration sensor device arranged in said first recirculation circuit or at said bottom region of said washing tub
Implementation Method 2
a first recirculation circuit suitable for withdrawing liquid from a bottom region of said washing tub and for re-admitting such a liquid into said bottom region of said washing tub
Data Source
Figure 1
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AI summary
The present invention relates to a method for washing laundry during a washing cycle in a laundry washing machine (1) comprising a washing drum (4); a washing tub (3) external to the washing drum (4); a water supply unit (5) to supply water (W) into the washing tub (3); an automatic dosing device (58) comprising a compartment suitable for receiving a quantity of detergent (D) sufficient for a plurality of washing cycles; a recirculation circuit (30) and a concentration sensor device (80). The method comprises the steps of: introducing a first prefixed quantity (Q1d) of detergent (D) and a first prefixed quantity (Q1w) of water (W) into the washing tub (3); activating the recirculation circuit (30) for mixing the first prefixed quantity (Q1d) of detergent (D) with the first prefixed quantity (Q1w) of water (W); determining the current concentration value (V) of the detergent (D); comparing the current concentration value (V) with one or more prefixed concentration levels (T1, T2) and either introducing or not introducing a second quantity (Q2d) of detergent (D) into the washing tub (3) according to the result of the comparison. The first prefixed quantity (Q1d) of detergent (D) and/or the second quantity (Q2d) of detergent (D) is determined on the base of the amount of laundry load (L). (FIG. 2)