Fluid top-off detection and control system
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Solution Overview
Problem
Existing fluid level sensing systems in cooking environments, such as deep fryers, face issues with debris interference, viscosity variations, and sanitation concerns, particularly with capillary sensors, which can lead to inaccurate readings and unsanitary conditions.
Innovation Solution
A capacitive sensor system that determines fluid levels by measuring capacitance between the sensor and the surrounding environment, using a capacitive sensor probe and electronics connected to a microcontroller for fluid management, capable of operating across a wide range of viscosities and temperatures, and is designed for easy cleaning and reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If float-based level sensors are used to detect fluid level, then the sensor can provide continuous level indication, but debris in the fluid causes the float to stick on the shaft, leading to inaccurate readings
Solution Approach 1:
The patent replaces the mechanical float-based level sensing system with a capacitive sensing system. The capacitive sensor detects fluid level through electrical field interaction with the fluid, eliminating mechanical moving parts that are susceptible to debris interference and sticking. This substitution of mechanical detection with electrical field-based detection resolves the reliability issue while maintaining measurement precision.
Solution Approach 2:
The capacitive sensor uses the fluid itself as an intermediary in the sensing mechanism. The sensor measures capacitance changes caused by the dielectric properties of the fluid, allowing level detection without direct mechanical contact between the sensor and fluid. This intermediary approach enables accurate measurement while avoiding the sticking problem that plagues direct mechanical float systems.
2Measurement precision
If capillary sensors are used to detect fluid level, then the sensor can determine level based on fluid position in the tube, but viscosity variations and temperature changes cause capillary action to fail, especially with partially solid fluids
Solution Approach 1:
The patent employs a capacitive sensing mechanism that responds to changes in dielectric constant and capacitance values as the fluid level changes. Unlike capillary sensors that rely on consistent surface tension and viscosity, the capacitive sensor adapts to varying fluid properties by measuring electrical field interactions, which remain reliable across different viscosities and temperatures including partially solid states.
Solution Approach 2:
The patent replaces the capillary action-based mechanical sensing system with an electrical field-based capacitive sensing system. This substitution eliminates dependence on fluid viscosity and surface tension properties, allowing the sensor to accurately detect fluid levels across a wide range of temperatures and viscosity conditions, including when the fluid is partially solid.
3Measurement precision
If capillary sensors are used in fluid level detection, then the sensor can provide continuous level monitoring, but fluid retention in the capillary creates unsanitary conditions that are difficult to clean
Solution Approach 1:
The patent replaces the capillary tube structure with a capacitive sensor that detects fluid level through electrical field interaction. This eliminates the enclosed capillary space where fluid would be retained and create sanitation issues. The capacitive sensor typically has an exposed sensing surface that can be easily cleaned or sterilized, resolving the sanitation problem while maintaining measurement capability.
4Device complexity
If air pockets are retained within the capillary sensor, then the sensor structure remains simple, but temperature changes cause the air pockets to expand or contract, leading to sensor failure
Solution Approach 1:
The patent replaces the capillary tube structure that traps air pockets with a capacitive sensing element. The capacitive sensor does not enclose air pockets in the same way, and its electrical field-based measurement is not susceptible to the expansion and contraction effects that cause capillary sensor failure under temperature variations. This substitution maintains structural simplicity while dramatically improving reliability in temperature-changing environments.
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 capacitive sensor system provides accurate and reliable fluid level detection, enabling automatic fluid supplementation or removal, maintaining safe operating conditions and reducing manual intervention, while ensuring sanitation and durability in harsh cooking environments.
Implementation Method 1
A capacitive sensor system that determines fluid levels by measuring capacitance between the sensor and the surrounding environment
Data Source
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AI summary
A capacitive sensor and control system is configured to detect the presence (or absence) of fluid within a container. Configured in a vat of a deep fryer, the sensor determines when a level of liquid within the vat is at or above the level of the sensor. The sensor is in communication with the control system and the sensor sends a signal to the control system representative of the presence or absence of liquid within the vat and at the level of the sensor. The controller receives the signal from the sensor, and allows operation of a fluid management system and its associated plumbing to maintain an appropriate level of liquid in the vat.