Temperature control using applied electromagnetic fields
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Solution Overview
Problem
Existing methods for determining the temperature and degree of freezing of products, especially in the food industry, face challenges such as invasive contact measurements, inaccurate non-contact infrared sensors, and instability in continuous freezing processes, which are affected by product size, shape, and internal temperature gradients.
Innovation Solution
A non-invasive method using electromagnetic fields to measure the phase angle of conductive products, which correlates with their temperature and degree of freezing, allowing for accurate temperature and freezing assessment independent of product size and shape, and enabling real-time adjustment of freezing processes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact temperature measurement methods (thermometer or thermocouple) are used, then temperature measurement is achieved, but the product is invasively contacted which may damage or contaminate the product
Solution Approach 1:
The patent replaces mechanical contact measurement systems (thermometers, thermocouples) with an electromagnetic field-based measurement system. The system applies electromagnetic fields to the product and measures impedance changes without physical contact, thereby eliminating product contamination or damage while maintaining measurement accuracy.
Solution Approach 2:
The patent introduces electromagnetic fields as an intermediary between the measurement system and the product. Instead of direct contact, the electromagnetic field interacts with the product's electrical properties (impedance, phase angle) to obtain temperature information, serving as a non-invasive mediator that eliminates harmful contact.
2Object-affected harmful factors
If infrared temperature sensors are used for noncontact measurement, then product contact is avoided, but measurement accuracy is limited to 3-4 degrees F. and only surface spot temperature is measured
Solution Approach 1:
The patent replaces infrared optical measurement with electromagnetic field-based electrical impedance measurement. This substitution enables noncontact measurement while achieving higher precision through phase angle detection, overcoming the 3-4 degrees F. accuracy limitation of infrared sensors.
Solution Approach 2:
The patent changes the measurement parameter from optical radiation detection (infrared) to electrical impedance and phase angle detection. By measuring the product's electrical response to applied electromagnetic fields, the system achieves superior temperature measurement accuracy while maintaining noncontact operation.
3Ease of operation
If infrared sensors measure surface temperature during freezing, then noncontact measurement is achieved, but internal temperature gradients cause poor correlation with final equilibrated temperature
Solution Approach 1:
The patent changes the measurement approach from detecting thermal radiation from surface elements to measuring the product's bulk electrical impedance and phase angle response. This parameter change enables detection of internal temperature distribution and average temperature, providing accurate correlation with final equilibrated temperature while maintaining noncontact operation.
Solution Approach 2:
The electromagnetic field measurement system provides universal measurement capability that works for both surface and internal temperature assessment. The phase angle measurement reflects the average temperature of the entire product volume, making it universally applicable for monitoring freezing progress and predicting final equilibrated temperature regardless of internal temperature gradients.
4Measurement precision
If temperature probes are inserted into products with internal temperature gradients, then internal temperature can be measured, but small variations in penetration depth result in significant inaccuracies
Solution Approach 1:
The patent replaces mechanical probe insertion with noncontact electromagnetic field measurement. This eliminates the operational variability associated with manual probe placement and penetration depth control, providing consistent and repeatable measurements without requiring precise positioning.
Solution Approach 2:
The electromagnetic field measurement system provides universal measurement capability that penetrates the entire product volume simultaneously. The phase angle measurement reflects the average temperature of all product elements regardless of their position or depth, eliminating the inconsistency caused by variable probe penetration depths.
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 method provides reliable, non-invasive temperature and freezing degree measurements, independent of product size and shape, enhancing process control and product quality by ensuring consistent temperature and freezing levels across varying product sizes and shapes.
Implementation Method 1
applying an electromagnetic field to the product, measuring the phase angle exhibited by the product in response to the electromagnetic field
Data Source
AI summary
Disclosed is a technique for characterizing a product utilizing novel measurements based on the reactive and resistive signals exhibited by the product in an electromagnetic field.