Oil quality sensor and deep frying device with such an oil quality sensor

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Solution Overview

Problem

Existing oil quality sensors for deep-frying devices face challenges in handling simplicity and safety, as well as measurement precision, with portable devices requiring operator activation and potential damage, and stationary sensors not meeting high precision requirements.

Innovation Solution

A permanently installed oil quality sensor with a cylindrical or tubular capacitor design, featuring a second temperature sensor to account for temperature gradients and a shielding electrode for interference protection, allowing for precise capacitance measurements and flexible operation across different oil types.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If a portable oil quality sensor is used, then the operator can manually measure oil quality, but the device requires operator activation and may be damaged by contact with the deep-frying basin

Engineering Contradiction:
Improvemanual measurement capabilityVSAvoiddevice damage risk
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The oil quality sensor is permanently installed in the frying device and automatically measures oil quality without requiring operator intervention. The sensor integrates temperature compensation and automatic capacitance measurement, making the system self-sufficient and eliminating manual handling risks.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent combines the oil quality sensor, temperature sensor, and evaluation unit into an integrated system permanently installed in the frying device. This merging of components eliminates the need for separate portable devices and ensures reliable operation within the frying environment.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a stationary oil quality sensor is used, then the device can be permanently installed, but the measurement precision does not meet high requirements

Engineering Contradiction:
Improvepermanent installationVSAvoidoil quality measurement accuracy
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The patent uses an elongated capacitor design with increased length to enhance the measurement signal. The extended capacitor provides a larger measurement volume and improved sensitivity, directly increasing measurement precision while maintaining permanent installation capability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces simple capacitance measurement with a sophisticated evaluation system that includes temperature compensation and correlation function-based polar component calculation. This substitution of basic measurement with advanced evaluation significantly improves measurement precision.

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

3Measurement precision

If a temperature gradient exists between the frying oil and oil quality sensor, then the dielectric constant measurement becomes inaccurate, but adding temperature compensation increases device complexity

Engineering Contradiction:
Improvedielectric constant accuracyVSAvoidtemperature compensation system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent introduces a temperature sensor as an intermediary element that measures the actual oil temperature. This temperature data is then used by the evaluation unit to compensate for thermal effects on the dielectric constant, accurately separating temperature effects from quality changes.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system implements feedback through temperature measurement and compensation. The temperature sensor continuously monitors oil temperature, and the evaluation unit uses this feedback to adjust the dielectric constant calculation, eliminating measurement errors caused by temperature gradients.

Inventive Principle:
Principle #23Feedback

4Device complexity

If an interdigital capacitor is used for measurement, then the device structure is simple, but the measurement precision is significantly lower compared to an elongated capacitor

Engineering Contradiction:
Improvecapacitor structureVSAvoidoil quality measurement accuracy
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent transitions from a planar interdigital capacitor to an elongated three-dimensional capacitor structure. This dimensional change increases the measurement volume and interaction between the electric field and oil sample, significantly improving measurement sensitivity and precision.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 solution ensures safer, simpler handling and significantly improved measurement precision by integrating temperature gradient management and interference shielding, enabling accurate oil quality assessment without operator intervention.

Implementation Method 1

measuring the capacitance of the deep-frying oil in a deep-frying device

Methodology Applied
Scientific EffectCapacitance: Capacitance

Implementation Method 2

the dielectric constant of the frying oil changes as it ages

Methodology Applied
Scientific EffectDielectric constant: Dielectric Permittivity

Implementation Method 3

the temperature of the frying oil is also measured using the known device, since the dielectric constant is not only dependent on the frying oil quality

Methodology Applied
Scientific EffectTemperature measurement:

Data Source

PatentEP2937692B1Oil quality sensor and deep frying device with such an oil quality sensor
Publication Date: 2017.06.07 XYLEM ANALYTICS GERMANY GMBH
  • EP2937692B1 patent drawingFigure 1~1b
  • EP2937692B1 patent drawingFigure 2~3

AI summary

An oil quality sensor to determine the quality of deep-frying oil by measuring the capacitance of the deep-frying oil in a deep fryer includes a housing and a hollow space in the housing through which the deep-frying oil is guided. An inlet opening introduces deep-frying oil to the hollow space, and a drain opening guides the deep-frying oil out of the hollow space. A first bent electrode extends along the hollow space, and a second bent electrode extends along the hollow space and is arranged opposite the first electrode, in which case the two electrodes form a capacitor and deep-frying oil is guided through the space formed between these two electrodes to measure its capacitance. A first temperature sensor measures the temperature of the oil used for deep frying that needs to be measured. An evaluation unit records the measured capacitance of the capacitor and the measured temperature, digitalizes these measured values, and calculates the polar fractions in the deep-frying oil, in which case these polar fractions are a criterion for the quality of the deep-frying oil.