Water Hardness Determination via SAW Sensor and Electrochemical Precipitation
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Solution Overview
Problem
Conventional methods for determining water hardness are limited by high maintenance and reagent requirements, inaccuracy, and high production costs, leading to inefficiencies in preventing or removing lime scale deposits in home appliances.
Innovation Solution
A method using electrochemical reactions to deposit lime scale on a surface, with mass determination via surface acoustic waves and verification using a radiation detector, allowing for accurate water hardness measurement without frequent electrode replacement or reagent use, and a device comprising a surface acoustic wave sensor, electrodes, and an electronic control unit to implement this method.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional methods (ion selective electrodes, EDTA titration, conductivity measurement) are used to determine water hardness, then measurement capability is provided, but maintenance frequency increases and measurement accuracy decreases
Solution Approach 1:
The patent replaces conventional electrochemical measurement systems (ion selective electrodes requiring frequent replacement) with a surface acoustic wave sensor system. The SAW sensor detects mass changes of deposited lime scale through acoustic wave frequency shifts, eliminating the need for fragile electrochemical electrodes and reagent dyes, thereby reducing maintenance and extending device lifetime while maintaining measurement accuracy.
Solution Approach 2:
The patent creates a controlled model of the scaling process by depositing lime scale on a working electrode under controlled conditions. Instead of measuring water hardness directly in its natural state, the system precipitates calcium carbonate deposits on a controlled surface and measures the deposit mass, providing an indirect but accurate representation of water hardness that is more stable and measurable.
2Object-affected harmful factors
If ion exchange resins are used to soften water, then lime scale prevention is improved, but glass corrosion occurs due to binding Ca2+
Solution Approach 1:
The patent replaces chemical water softening methods (ion exchange resins) with an electrochemical precipitation system. By applying controlled voltage to precipitate calcium carbonate on a working electrode, the system removes lime scale-forming minerals through controlled deposition rather than ion exchange, avoiding the glass corrosion problem associated with resin-based softening while effectively preventing scale deposits in appliances.
3Measurement precision
If conventional measurement devices are used, then water hardness can be determined, but production costs and maintenance requirements increase
Solution Approach 1:
The patent replaces expensive electrochemical measurement systems with a surface acoustic wave sensor platform. The SAW sensor technology, combined with electrochemical precipitation, provides a more cost-effective solution that eliminates the need for expensive reagent dyes and frequently replaceable electrodes, reducing both production costs and ongoing maintenance requirements while maintaining accurate water hardness determination capability.
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 provides a low-maintenance, cost-effective, and highly accurate method for determining water hardness, reducing lime scale-related issues in home appliances and minimizing detergent usage, thus enhancing appliance performance and environmental sustainability.
Implementation Method 1
determine the mass of the deposits by means of a surface acoustic wave sensor
Implementation Method 2
the surface cover rate and, alternatively or additionally, the height are determined by means of the radiation detector detecting the wavelength and/or intensity and, alternatively or additionally, spatial distribution of the, particularly fluorescent, radiation emitted by the deposits
Implementation Method 3
applying a voltage to the water such that deposits are precipitated on the surface
Data Source
Figure 1
AI summary
The present invention relates to a method and a device (1) for determining water hardness, and a home appliance comprising such a device (1). The method for determining water hardness comprises providing water to be analyzed on a surface. The method further comprises applying a voltage to the water such that deposits (11) are precipitated on the surface, and determining the mass of the deposits (11) by means of a surface acoustic wave sensor (2). Furthermore, the method comprises determining the water hardness from the determined mass.