Capacitive Oil Quality Sensor Layout Against Fouling and Heat Gradients
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Solution Overview
Problem
Existing capacitive measurement devices for cooking oil quality and deterioration in deep fat fryers face challenges due to water and impurities accumulating in the sensor, temperature gradients affecting measurement accuracy, and the need for reliable detection of oil deterioration beyond subjective visual and olfactory inspections.
Innovation Solution
A capacitive sensor with a pair of flat comb-shaped electrodes, encapsulated in a perforated case, is oriented in the vat with its longitudinal axis parallel to the bottom and forming an angle of 0° to 60° with the vertical direction, minimizing temperature gradient effects and allowing oil flow to clean the sensor, while being secured underneath the heating element for improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the capacitive sensor is placed directly in the vat for measurement, then the measurement capability is improved, but water and impurities accumulate in the sensor causing measurement errors
Solution Approach 1:
The sensor is encapsulated in a perforated protective case that allows oil to pass through while protecting the sensor from water and impurity accumulation. The perforated structure enables selective permeability to different substances in the frying environment.
Solution Approach 2:
The sensor is oriented at a specific angle (0° to 60° with the vertical direction) rather than being placed horizontally or vertically. This angular orientation allows oil flow to naturally clean the sensor surface while maintaining measurement capability, utilizing the third dimension for solution.
2Measurement precision
If the sensor is positioned in the vat for direct measurement, then measurement access is improved, but temperature gradients affect measurement accuracy
Solution Approach 1:
The sensor is oriented at a specific angle (0° to 60° with the vertical direction) rather than being placed horizontally or vertically. This angular orientation allows oil flow to naturally clean the sensor surface while maintaining measurement capability, utilizing the third dimension for solution.
Solution Approach 2:
The perforated protective case acts as an intermediary between the sensor and the frying environment. It allows the sensor to be exposed to oil for measurement while being protected from extreme temperature fluctuations and direct contact with water and impurities.
3Reliability
If the sensor is placed in the vat for continuous monitoring, then detection reliability is improved, but cleaning and maintenance become difficult
Solution Approach 1:
The sensor orientation and perforated case design enable self-cleaning functionality. Oil flow naturally passes through the perforations and cleans the sensor surface during normal operation, eliminating the need for manual cleaning while maintaining detection reliability.
Solution Approach 2:
The perforated protective case allows oil to pass through while protecting the sensor from water and impurity accumulation. The perforated structure enables selective permeability to different substances in the frying environment.
4Device complexity
If the sensor is oriented horizontally for measurement, then structural simplicity is improved, but water and steam blocks the sensor surface
Solution Approach 1:
The sensor is oriented at a specific angle (0° to 60° with the vertical direction) rather than being placed horizontally or vertically. This angular orientation allows oil flow to naturally clean the sensor surface while maintaining measurement capability, utilizing the third dimension for solution.
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 enhances the reliability and accuracy of capacitive measurements by reducing the impact of temperature gradients and impurities, ensuring the sensor remains clean and functional, thus providing a more objective and efficient method for detecting oil quality and deterioration.
Implementation Method 1
a device for the capacitive measurement of the quality and/or deterioration of a fluid
Implementation Method 2
the temperature greatly influences the dielectric constant of the oil, and thus its capacitance
Implementation Method 3
When a deep fat fryer is switched on, the temperature above the heating element reaches approximately 180° C.
Implementation Method 4
the temperature gradients present in the vat
Implementation Method 5
Part of the water passes from the liquid state to the steam state, which will produce natural mixing, which will also cause the water at the bottom of the vat to rise.
Data Source
AI summary
A device for capacitive measurement of the quality and/or deterioration of a fluid includes a sensor encapsulated in a perforated case fixed in the vat of a cooking apparatus that has a bottom, wherein the sensor is connected to an electronic processing circuit, wherein the sensor includes a pair of flat electrodes each having the shape of a comb with a plurality of teeth, which are approximately parallel to each other and extends from a base, wherein the electrodes are arranged relative to each other so teeth of one electrode fit between teeth of the other electrode in approximately the same plane, and the encapsulated sensor is oriented in the vat so the longitudinal axis of each electrode base extends parallel to the bottom of the vat and so the plane of the sensor electrodes forms an angle of between 0° and 60° with the vertical direction.