Dishwasher Detergent Dosing Calibration Using Conductivity Reference
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Solution Overview
Problem
Existing dishwasher detergent dosing methods are inefficient due to sensor degradation and water quality variations, leading to suboptimal mixing conditions, excessive detergent use, and increased operational costs, with manual interventions often required to correct malfunctions.
Innovation Solution
An autocalibrating dosing method that sets a reference conductivity value during the first load, allowing automatic calibration and decoupling from water quality and probe cleanliness factors, reducing manual intervention and ensuring consistent detergent dosing throughout the washing cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If conventional dosing methods using conductivity sensors are used, then detergent dosing can be automated, but sensor degradation and residues accumulation distort measurements leading to excessive detergent use
Solution Approach 1:
The system performs a first load operation before normal dosing to establish a reference conductivity value. This preliminary action calibrates the system by accounting for sensor characteristics and water quality variations before actual automated dosing begins, ensuring accurate measurements throughout operation.
Solution Approach 2:
The patent changes the reference parameter from fixed threshold values to dynamically established conductivity values measured during the first load. By measuring actual conductivity during initial operation and using this as reference, the system adapts to specific sensor and water conditions, maintaining measurement precision despite sensor degradation over time.
2Ease of operation
If fixed threshold conductivity values are used for dosing, then dosing control is simplified, but water quality variations cause suboptimal mixing conditions
Solution Approach 1:
The system implements feedback by measuring conductivity during the first load, establishing a reference value specific to current water quality and sensor conditions, then using this reference to control subsequent dosing operations. This closed-loop approach maintains accurate detergent concentration despite variations in water quality.
Solution Approach 2:
The first load operation serves multiple functions: it cleans the sensor probe, characterizes water quality, establishes the reference conductivity value, and prepares the tank for normal operation. This multi-functional approach simplifies operation while ensuring accurate dosing control adapted to specific conditions.
3Measurement precision
If manual intervention is required to correct dosing malfunctions, then dosing accuracy can be adjusted, but operational time and costs increase
Solution Approach 1:
The system performs self-calibration automatically during the first load operation without requiring manual intervention. The controller autonomously measures conductivity, establishes reference values, and configures dosing parameters, eliminating the need for manual adjustment while maintaining dosing accuracy throughout operation.
4Reliability
If probe cleaning is required to maintain measurement accuracy, then measurement reliability improves, but operational interruptions increase
Solution Approach 1:
The system performs probe cleaning as a preliminary action during the first load operation before normal dosing begins. By cleaning the probe in advance and establishing reference values at this stage, the system ensures measurement reliability during productive washing cycles without causing operational interruptions.
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 method significantly reduces chemical waste, maintains dishwasher integrity, and decreases operational costs by ensuring optimal detergent concentration and efficient washing cycles, minimizing the need for manual adjustments and probe cleaning.
Implementation Method 1
a first conductivity value of the washing liquid is detected by a dosing system
Data Source
Figure 1
AI summary
Dosing method for dosing a chemical product, particularly a detergent, in a dishwasher, comprising the steps: detecting a first loading signal of a washing liquid in a washing tank of the dishwasher; dosing a first quantity of chemical product in said washing liquid to obtain a washing mixture; detecting a conductivity value of said washing mixture at a first loading condition of the dishwasher; storing a conductivity threshold value equal to said conductivity value of said washing mixture at a first loading condition; dosing of a further quantity of chemical product in said washing mixture at an operation condition of the dishwasher in such a way to adjust a further conductivity value of said washing mixture detected in said operating condition until reaching said conductivity threshold value.