High-Frequency Resistive Heating for Liquid Pasteurization
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Solution Overview
Problem
Existing methods for electrical heating of liquid food products, such as pasteurization, often result in electrode degeneration and undesired contamination due to low frequencies, and fail to achieve homogeneous heating, leading to reduced product quality.
Innovation Solution
A process using an apparatus with at least two vertically mounted heating chambers connected by electrodes with continuous DC power, where the electrical charge polarity is reversed at high frequency (at least 500 Hz) to achieve fast and homogeneous resistive heating without electrolysis, ensuring the quality of the heated liquid product.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If low frequency electrical current is used for resistive heating of liquid products, then heating can be achieved, but electrode degeneration and undesired contamination occur
Solution Approach 1:
The patent changes the frequency parameter from low frequency (causing electrode degradation) to high frequency of at least 500 Hz. This parameter change enables resistive heating while preventing electrode degeneration and contamination, as the high frequency prevents harmful electrochemical reactions at the electrodes.
Solution Approach 2:
The patent employs periodic reversal of electrical charge polarity at high frequency (at least 500 Hz). This periodic action prevents charge accumulation at electrodes, eliminating electrode degeneration and contamination while maintaining effective resistive heating of the liquid product.
2Reliability
If conventional heating methods are used, then pasteurization can be achieved, but homogeneous heating is not achieved, leading to reduced product quality
Solution Approach 1:
The patent replaces conventional mechanical/convective heating systems with an electrical field-based resistive heating system. This substitution enables homogeneous heating throughout the liquid product while achieving the required microbial reduction, as the electrical field penetrates uniformly throughout the product volume.
Solution Approach 2:
The patent changes the heating mechanism from convective/condductive heat transfer to resistive heating through electrical current. This parameter change in the heating mechanism enables uniform energy distribution and homogeneous temperature rise throughout the liquid product, eliminating cold spots and improving heating precision.
3Reliability
If high temperature heating is used for pasteurization, then microbial reduction is achieved, but product quality in terms of taste, flavor and nutrient content deteriorates
Solution Approach 1:
The patent changes the heating parameter from high temperature to lower temperature operation. By using high frequency electrical resistive heating, the process achieves effective microbial reduction at lower temperatures that preserve product quality, including taste, flavor, and nutrient content.
Solution Approach 2:
The patent substitutes conventional thermal heating with electrical resistive heating. This substitution enables more efficient energy transfer directly to the product molecules, achieving pasteurization at lower bulk temperatures and shorter times, thereby minimizing thermal degradation of quality attributes.
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
The process provides a liquid product with extended shelf life and improved taste, flavor, and nutrient content, achieving the same microbial reduction as conventional methods at lower temperatures with no holding time for temperature equalization, thus maintaining product quality.
Implementation Method 1
continuously generating an electrical current through the liquid product flowing through the heating chambers by continuously applying an electrical potential over the first and second electrode of each heating chamber
Data Source
AI summary
The invention relates to an apparatus for fast and homogeneously heating a liquid product to a heating temperature by means of resistive heating, the apparatus comprising at least two vertically mounted, longitudinal, heating chambers that are arranged in series.The invention further relates to a process for fast and homogeneously heating a liquid product to a heating temperature by means of resistive heating in such apparatus comprising(a) continuously supplying the liquid product to the first heating chamber in series and flowing the liquid product continuously through the at least two heating chambers;(b) continuously generating an electrical current through the liquid product flowing through the heating chambers by continuously applying an electrical potential over each heating chamber, wherein the direction of the current is continuously alternated with a frequency of at least 500 Hz, to obtain heated liquid product; and(c) continuously discharging heated liquid product from the last heating chamber in series,wherein the liquid product has an electrical conductivity of at least 0.03 S/m.