Water Heater Flow Pulsation to Limit Heat Exchanger Scale
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Solution Overview
Problem
Conventional water heaters face issues with scale adhesion to the heat exchanger surfaces, leading to reduced heat-transfer performance and flow channel obstruction, as detached calcium carbonate scale reattaches during circulation.
Innovation Solution
Applying pulsation to the liquid flow between the hot water supply tank and the heater, while controlling the number of circulation times to prevent scale reattachment on the heat-transfer surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If high-temperature water is used to heat the liquid, then heat-transfer performance is improved, but scale adhesion to the heat exchanger surface increases
Solution Approach 1:
The patent applies periodic pulsation to the liquid flow through the heat exchanger, creating cyclic flow patterns that prevent scale from firmly adhering to the heat transfer surface while maintaining high temperature operation for effective heating
Solution Approach 2:
The pulsating flow creates mechanical vibration and shear forces on the heat exchanger surface, which prevents scale accumulation by continuously disrupting the boundary layer where scale would form, allowing high-temperature operation without scale adhesion problems
2Productivity
If the liquid is circulated multiple times through the heat exchanger, then heating efficiency is improved, but detached scale reattaches to the heat-transfer surface
Solution Approach 1:
The patent implements periodic pulsation during the circulation process, creating alternating high-velocity and low-velocity flow phases that detach scale during high-velocity phases while preventing reattachment during subsequent phases, enabling multiple circulation passes without scale reaccumulation
3Object-generated harmful factors
If pulsation is applied to detach scale, then scale removal is improved, but detached scale returns and reattaches during circulation
Solution Approach 1:
The patent uses sustained periodic pulsation throughout the circulation cycle, creating repeated shear force applications that prevent detached scale from settling and reattaching to the heat exchanger surface, ensuring scale remains suspended in the flow
Solution Approach 2:
The patent maintains continuous pulsation during the entire circulation process, ensuring that the scale-detaching effect is continuously applied rather than being intermittent, which prevents both initial attachment and subsequent reattachment of scale particles
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
Effectively reduces scale adhesion, maintaining heat-transfer performance and preventing flow channel obstruction by detaching and preventing reattachment of scale on the heat exchanger surfaces.
Implementation Method 1
Applying pulsation to the liquid flow between the hot water supply tank and the heater
Implementation Method 2
a heat exchanger for transferring heat to water
Data Source
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AI summary
There is provided a water heater in which scale adhesion to the inner wall of a liquid to-be-heated flowing channel in a heat exchanger that constitutes the water heater is reduced, and lowering of heat transfer performance and obstruction of the flow channel due to the scale adhesion is reduced. By applying pulsation of a liquid to be heated which circulates between a tank (1) and a heat exchanger (3), scale that has been deposited on the inner wall (heat-transfer surface) of a liquid to-be-heated flow channel (31) in a heat exchanger (3) is detached, and the number of times of circulation of the liquid to be heated which circulates between the tank and the heat exchanger is controlled to be three times or less. A distribution control unit (101) pulsates the to-be heated liquid that passes through the liquid to-be-heated flow channel (31) of the heat exchanger (31), and also controls a flow rate of the liquid to-be-heated which passes through the liquid to-be-heated flow channel (31) so that the number of times of circulation indicating the number of times at which the entire volume of the liquid to-be-heated stored in the tank (1) passes through the heat exchanger (3) is three times or less. The number of times of circulation is determined, based on the entire volume of the liquid to-be-heated stored in the tank (1), a boiling time to be taken for the entire volume of the liquid to-be-heated in the tank (1) to reach a predetermined temperature, and the flow rate of the liquid to-be-heated which passes through the liquid to-be-heated flow channel (31).