Capacitance Sensor in Oil Return Line for Fryer Quality Detection

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Solution Overview

Problem

Existing methods for determining the quality of cooking oil in fryers are subjective, time-consuming, or unreliable, and current sensors often fail to accurately detect the level of total polar materials (TPMs) in oil, which indicates oil degradation.

Innovation Solution

A capacitance sensor is positioned externally in the oil return line of a fryer, measuring the dielectric constant of the cooking oil as it flows past, providing an indication when the oil's quality has deteriorated, thereby detecting unacceptable levels of TPMs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If simple methods such as testing taste, smell and color are used to determine oil quality, then the testing process is simple, but the accuracy and reliability are excessively subjective and too time consuming

Engineering Contradiction:
Improvesimplicity of testing methodVSAvoidaccuracy of oil quality detection
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent replaces subjective sensory testing (taste, smell, color) with an automated capacitance sensing system. The sensor measures electrical properties of the oil to detect TPM levels, substituting human senses with precise electronic measurement that provides objective, quantitative data without being subjective or time-consuming

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention changes the measurement parameter from sensory attributes (taste, smell, color) to electrical properties (capacitance, dielectric constant). By measuring how TPMs alter the oil's electrical characteristics, the system achieves accurate, automated detection that resolves the contradiction between simplicity and precision

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If chemical or chromatographic methods are used to test oil quality, then the comprehensive and accurate detection is achieved, but the process becomes time consuming and expensive

Engineering Contradiction:
Improvecomprehensive and accurate detection of TPMsVSAvoidtime consuming and expensive testing process
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent substitutes complex chemical and chromatographic analysis systems with a simple capacitance sensor. The sensor directly measures electrical properties that correlate with TPM content, eliminating the need for time-consuming chemical reactions, sample preparation, and complex instrumentation while maintaining accurate detection capability

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The invention shifts from measuring chemical composition through complex analytical chemistry to measuring electrical parameters (capacitance, dielectric constant). This parameter transformation enables rapid, continuous monitoring without the time and cost overhead of chemical methods, while still providing comprehensive TPM detection

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If a sensor is disposed inside a fryer pot to measure oil quality, then the measurement can be performed directly in the oil, but the sensor is exposed to high temperatures and oil debris that may affect reliability

Engineering Contradiction:
Improvedirect measurement capability in oilVSAvoidsensor durability in harsh environment
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent extracts the sensor from the harsh high-temperature environment inside the fryer pot and relocates it to the cooler return line where oil flows after leaving the cooking zone. This extraction maintains the ability to measure oil quality while protecting the sensor from thermal degradation and physical damage from debris

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The return line oil flow serves as an intermediary medium that carries oil quality information from the cooking zone to the sensor location. By measuring the electrical properties of oil in the return line, the system indirectly monitors cooking oil quality without exposing the sensor to the extreme conditions of the frying zone

Inventive Principle:
Principle #24Intermediary (Mediator)

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 solution allows for accurate and timely detection of oil degradation, preventing waste and ensuring food safety by measuring the capacitance of filtered oil repeatedly and averaging the values to determine when the oil should be changed.

Implementation Method 1

an increased capacitance measurement of the cooking oil is indicative of an increased level of TPMs in the cooking oil

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

measuring the an electrical property of the cooking oil... measures the capacitance of the cooking oil... measures a dielectric constant of the cooking oil

Methodology Applied
Scientific EffectDielectric constant: Dielectric Permittivity

Data Source

PatentEP2712665B1Oil quality sensor and adapter for deep fryers
Publication Date: 2017.08.09 THE FRYMASTER CORP LLC
  • EP2712665B1 patent drawingFigure 1
  • EP2712665B1 patent drawingFigure 2
  • EP2712665B1 patent drawingFigure 3

AI summary

A system for measuring the state of degradation of cooking oil or fat includes at least one fryer pot; a conduit fluidly connected to the fryer pot for transporting cooking oil from the fryer pot and returning the cooking oil back to the fryer pot. A means for re-circulating cooking oil to and from the fryer pot; and a sensor disposed in fluid communication with the conduit that measures an electrical property of the cooking oil as the cooking oil flows past the sensor and is returned to the at least one fryer pot is provided.