Apparatus and method for the ohmic heating of a particulate liquid
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Solution Overview
Problem
Existing ohmic heating technologies for conductive liquids, particularly particulate liquids like fruit juices, face issues such as arcing and electrode wear due to high current densities, leading to contamination and seal damage, and are cumbersome due to large electrode arrangements.
Innovation Solution
The electrode configuration features an abrupt change in direction between the inlet and outlet (60°-120°, preferably 90°) to promote turbulence, reducing current density on the periphery by increasing contact time with the central region, and includes a concave outer surface and multiple ports to enhance even current distribution, along with a dielectric tube connecting electrodes and a series arrangement of heating cells to manage temperature and resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high current density is used for ohmic heating, then heating efficiency is improved, but arcing occurs leading to electrode wear and liquid contamination
Solution Approach 1:
The electrode surface is made concave to create non-uniform current distribution, concentrating current in the central region away from the periphery where arcing typically occurs. This local geometric modification changes the current density profile to prevent electrode damage while maintaining heating efficiency.
Solution Approach 2:
Multiple ports are introduced to distribute the liquid flow across different regions of the electrode surface. This adds a spatial dimension to the heating process, ensuring current is drawn from multiple locations rather than concentrating at the periphery, thereby preventing arcing and electrode wear.
2Productivity
If high current density is used for ohmic heating, then heating efficiency is improved, but arcing occurs leading to liquid contamination
Solution Approach 1:
The concave electrode geometry directs current away from the peripheral regions where arcing and particle generation occur, focusing heating in the central region. This prevents electrode material from being eroded and contaminating the liquid while maintaining effective heating.
Solution Approach 2:
The design accepts that current naturally concentrates at the periphery (which would cause arcing), but uses the concave geometry to redirect this current concentration to the central region, converting the harmful peripheral arcing into beneficial central heating.
3Reliability
If large electrode surfaces are used to reduce current density, then electrode wear is reduced, but device complexity and size increase
Solution Approach 1:
The electrode is divided into multiple ports instead of using a single large electrode surface. This segmentation allows current to be distributed across multiple smaller openings, reducing current density and preventing wear without requiring an excessively large overall electrode structure.
Solution Approach 2:
Instead of increasing electrode surface area in two dimensions, the invention uses multiple ports to distribute current in three-dimensional space, achieving reduced current density without proportionally increasing the overall device size or 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 configuration reduces electrode wear, minimizes arcing, and ensures uniform heating by spreading current evenly, maintaining the quality of the heated liquid and preventing electrode contamination, while also being more compact and efficient in design.
Implementation Method 1
heating a conductive liquid by circulating an electric current therein through a pair of electrodes, the conductive liquid being the resistive element which is electrically heated. This is called ohmic or resistive heating
Implementation Method 2
there is a change of direction of 60°-120° between the inlet and the outlet, and preferably of 73°-107°. This involves a rather abrupt change of direction of the flow upon passage from the inlet to the outlet, which promotes turbulences that make the contact between the surface of the electrode and the conductive liquid to last longer
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
An electrode (10) for the ohmic heating of a particulate liquid flowing therethrough comprises an inlet (11; 12) and an outlet (12; 11) that are fluidly connected and are arranged in such a way that there is a change of direction of 60°-120° between the inlet and the outlet. A cell (50) for the ohmic heating of a particulate liquid flowing therethrough comprises two such electrodes and a dielectric tube (20) that fluidly connects the two electrodes. An apparatus for the ohmic heating of a particulate liquid flowing therethrough comprises six such cells that are fluidly connected in series and are electrically connected to a triphasic power supply, so that the increase of temperature of the liquid at any cell is substantially the same.