Direct Resistance Liquid Heater With Switch Matrix Power Control
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Solution Overview
Problem
Existing tankless liquid heating devices face issues such as 'dry firing', excessive thermal resistance, latent heat management, deposit formation, and power supply fluctuations, which lead to inefficiencies and increased costs due to the use of resistance type electrical heating elements and direct electrical resistance (DER) heating methods.
Innovation Solution
A direct electrical resistance liquid heater with non-uniformly spaced electrodes and a switch matrix that adjusts electrical current and power delivery based on electrode spacing and switch configurations, utilizing semiconductor switches to control heating power and maintain temperature set-points, while minimizing triac current requirements and power supply fluctuations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If resistance type electrical heating elements are used to heat liquid, then heating function is provided, but dry firing occurs causing element failure and safety hazards
Solution Approach 1:
The patent extracts the heating function from a separate heating element and integrates it directly into the liquid flow path through the liquid itself. By using the liquid as the resistive heating medium rather than a separate element, the system eliminates the heating element that would otherwise be subject to dry firing damage.
Solution Approach 2:
The patent introduces electrodes as intermediaries that apply electrical current directly to the liquid flow. The liquid itself becomes the resistive medium between electrodes, eliminating the need for a separate heating element that requires thermal contact with the liquid.
2Reliability
If larger heating chambers are used to manage latent heat and prevent scalding, then safety is improved, but response time to demand changes decreases
Solution Approach 1:
The patent employs dynamic control of electrical current applied to the liquid through the switch matrix. The system can rapidly adjust or completely cut off power to the heating zone, enabling fast response to flow changes without requiring large thermal mass for safety.
Solution Approach 2:
The system dynamically changes the electrical parameters (current, voltage, power levels) applied to the liquid based on real-time flow detection. This allows the heating chamber to remain small while maintaining safety through active control rather than passive thermal mass.
3Reliability
If multiple temperature sensors and flow detectors are used to prevent overheating, then temperature control reliability is improved, but device complexity and cost increase
Solution Approach 1:
The liquid itself serves multiple functions: it is the medium being heated, the resistive heating element, and the thermal conductor for temperature sensing. The electrodes serve dual purposes of applying current and detecting liquid presence through current flow, eliminating separate sensors.
Solution Approach 2:
The liquid flow itself provides the sensing function through its effect on electrical current between electrodes. When liquid flows between the electrodes, it completes the electrical circuit and allows current flow; when absent, the circuit is broken. This self-sensing eliminates the need for separate flow detectors.
4Ease of manufacture
If electrodes are uniformly spaced, then manufacturing is simplified, but current distribution and heating uniformity deteriorate
Solution Approach 1:
The patent deliberately uses non-uniform electrode spacing to optimize current distribution and heating uniformity across the liquid flow path. The asymmetric spacing compensates for variations in liquid conductivity and flow patterns, creating more uniform heating despite increased manufacturing complexity.
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 solution provides a wide range of current and power control, reduces power supply fluctuations, and ensures efficient heating with minimal triac current requirements, achieving uniform temperature control and rapid response to liquid flow changes, thus overcoming the limitations of previous technologies.
Implementation Method 1
A liquid heater comprising a liquid inlet, a plurality of electrodes (4) defining a plurality of channels, the spaces between the electrodes, through each of which liquid flows from the liquid inlet to the liquid outlet, the liquid being heated when it flows through the channels and a voltage is applied between electrodes
Data Source
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AI summary
The Direct Electric Resistance Liquid Heater comprises a liquid heating chamber containing a plurality of electrodes The electrodes are spaced apart to create a plurality of channels through which the liquid to be heated passes The electrodes are each connected to a power supply by one or more switches A controller controls the switches based upon data received from a temperature sensor sensing the temperature of the liquid and/or an electric current sensor sensing the current utilized by the liquid heater Selection of the number and spacing of the electrodes, and the number of switches provides the controller with various current levels options to apply to the liquid to be heated The current levels available span the range from minimum current to maximum current such that the controller can incrementally Increase or decrease the current applied to the liquid without disrupting other users of the same power source