Water Heater Element AC Descaling for Hard Water Scale Control
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Solution Overview
Problem
Existing water heating devices face issues with scale formation on heating elements due to hard water, leading to performance degradation and potential device failure, with existing solutions involving chemical additives or physical methods that have limitations in efficacy and complexity.
Innovation Solution
An electrochemical method using AC signals with different frequencies and a DC component to prevent or remove scale by depositing it on electrodes, where AC voltages with specific frequency ratios and triangular wave shapes are applied between the heating element and a counter electrode, effectively preventing scale adhesion and promoting its release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If chemical additives (ion exchangers or phosphonates) are used to prevent scale formation, then scale prevention effectiveness is improved, but device complexity and operational complexity increase due to cartridge replacement or continuous chemical addition
Solution Approach 1:
The patent replaces chemical methods (ion exchangers and phosphonates) with an electrochemical method using AC and DC voltages applied to electrodes in the water heater. This substitution eliminates the need for chemical cartridges or continuous chemical addition systems, thereby reducing device complexity while maintaining scale prevention effectiveness through electrochemical scale inhibition
Solution Approach 2:
The electrochemical scale prevention system operates automatically without requiring user intervention for cartridge replacement or chemical refilling. The AC and DC voltage application continues autonomously during water heating operations, providing self-service scale prevention that reduces operational complexity
2Reliability
If ion exchange cartridges are used for scale prevention, then scale formation is reduced, but maintenance requirements increase due to periodic cartridge replacement or regeneration
Solution Approach 1:
The patent replaces mechanical ion exchange cartridges with an electrochemical system using AC/DC voltages. This eliminates consumable components that require replacement, transforming maintenance-intensive chemical filtration into a maintenance-free electrochemical process that continues operating throughout the device lifetime
Solution Approach 2:
The invention eliminates disposable ion exchange cartridges by using durable electrodes that can operate indefinitely. The AC and DC voltage application provides continuous scale prevention without consuming materials, removing the need for periodic cartridge disposal and replacement
3Reliability
If phosphonates are continuously added to prevent scale, then scale prevention is maintained, but operational complexity increases due to continuous monitoring and addition systems
Solution Approach 1:
The patent replaces continuous chemical phosphonate addition systems with an electrochemical AC/DC voltage application system. This substitution eliminates the need for chemical storage tanks, dosing pumps, and monitoring systems, thereby simplifying operation while maintaining effective scale prevention through electrochemical means
Solution Approach 2:
The electrochemical scale prevention operates automatically during normal water heating without requiring user intervention for chemical addition or system monitoring. The AC and DC voltages are applied continuously or periodically by the control system, providing self-service operation that enhances ease of use
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 efficiently prevents scale formation and removal on heating elements, reducing corrosion risks and maintaining device performance without the need for continuous chemical addition, offering a more reliable and efficient solution compared to existing methods.
Implementation Method 1
When an alternating current (AC) is supplied to the electrodes, alternating acid and base will be formed at the electrodes. While scale is formed during boiling it will substantially not adhere to the electrode walls as it is constantly dissolved and re-precipitated at the electrode surface.
Implementation Method 2
A water heating device has a heating element, such as an immersion heater or a heatable wall, for heating an aqueous liquid, such as water
Data Source
Figure 1a~1b
Figure 1c~1d
Figure 1e~1f
AI summary
The invention provides a method of using a water heater arranged for heating an aqueous liquid wherein the water heater comprises a heating element to heat aqueous liquid in the water heater. The method comprising (a) heating aqueous liquid in the water heater with the heating element, wherein the heating element is in contact with the aqueous liquid; and (b) applying a first AC voltage between the heating element and a counter electrode and applying a second AC voltage between the heating element and the counter electrode, wherein the second AC voltage has a second AC frequency selected from the range of 0.02 Hz - 5 Hz and wherein the ratio between the first AC frequency and the second AC frequency is 2 or more.