Needle Electrode Arrays for Uniform Ohmic Food Heating
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Solution Overview
Problem
Existing ohmic heating methods for food products result in uneven heating due to air pockets and gas formation, leading to disruptions in the production process, particularly with large contact areas, and require significant effort to maintain relative motion between the food and conductive surfaces.
Innovation Solution
The method employs electrodes designed as needle combs or brushes with controlled high-frequency energy, penetrating the insulating casing to pierce the food, ensuring complete piercing before power activation, and using pulsed current to prevent hot spots, with rotational movement for minimal invasiveness and sealing the entry points.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If large contact areas are used for ohmic heating, then heating efficiency is improved, but air pockets and gas formation occur leading to uneven heating
Solution Approach 1:
The patent divides the contact surface into multiple discrete needle electrodes arranged in arrays rather than using large continuous contact areas. This segmentation allows the electric field to be distributed across many small points, maintaining heating efficiency while preventing air pocket formation and gas accumulation that occur with large continuous contacts. The needle electrodes penetrate the food product to create multiple small current paths throughout the volume.
Solution Approach 2:
The invention transitions from surface-level heating contacts to three-dimensional penetration by inserting needles through the entire thickness of the food product. This dimensional change allows current to flow through the bulk material rather than just heating the surface, achieving uniform volumetric heating without the air pocket problems associated with large surface contacts.
2Manufacturing precision
If relative motion is generated between filling material and conductive surfaces to reduce air pockets, then heating uniformity is improved, but device complexity and operational effort increase
Solution Approach 1:
The patent replaces the mechanical relative motion system with an electrical field-based solution. Instead of moving the food product or electrodes relative to each other to prevent air pocket formation, the invention uses penetrating needle electrodes that create direct current paths through the material, eliminating the need for complex mechanical motion systems while achieving uniform heating.
Solution Approach 2:
The needle electrodes are inserted into the food product before the heating process begins, pre-establishing conductive paths through the material. This preliminary penetration action ensures that current can flow uniformly throughout the product from the start of heating, preventing air pocket formation without requiring subsequent mechanical motion during the heating process.
3Productivity
If continuous current is applied for heating, then productivity is improved, but hot spots form disrupting the production process
Solution Approach 1:
The patent employs pulsed or modulated current application through the needle electrode arrays rather than continuous DC current. The periodic activation of different electrode groups allows heat to distribute evenly throughout the product between pulses, preventing localized hot spots while maintaining high overall heating rates for improved productivity and process reliability.
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
Achieves uniform and rapid heating without hot spots, allowing continuous industrial production by minimizing gas formation and ensuring even temperature distribution through controlled electrode penetration and high-frequency energy application.
Implementation Method 1
The invention relates to a method for treating a foodstuff by means of non-conventional, ohmic heating, for heating raw material contained in a casing
Data Source
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AI summary
The invention relates to a method for treating a food product by means of non-conventional resistive heating. The heating serves, in particular, to treat sausage products in an intestine, such as Brühwurst (scalded sausage), hot dogs or similar food products. The respective food product is brought into contact with spaced-apart electrically conductive electrodes, wherein the electrodes are connected to a controllable power source. According to the invention, the electrodes are each in the form of at least one first and one second electrode group, wherein the electrode groups are at a distance AEG in relation to one another. Each electrode group has a number of individual electrodes, similar to a comb-like set of needles, wherein the neighbouring individual electrodes of the comb-like set of needles are each at a distance AEE from one another. The distance AEG is greater than or at most equal to the distance AEE. The respective comb-like set of needles passes through the food product, wherein a punching process is realized in such a way that, based on the food product, inlet and outlet points of the comb-like set of needles, based on the encapsulation or sheathing, produce at least penetration points and the product being treated is accommodated in the space between two conveyor belts and the individual electrodes extend from at least one of the conveyor belts in the direction of the opposite conveyor belt.