Capacitive Fluid Level Sensor Non-Contact Measurement
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Solution Overview
Problem
Existing capacitive fluid level sensors face challenges in installation, particularly when dealing with volatile fluids or containers that are difficult to access, as they often require electrodes to be inserted into the fluid or coupled to the external surface, leading to design complications, increased costs, and user experience issues.
Innovation Solution
A fluid dispensing system utilizing a target capacitance sensor and an ambient capacitance sensor positioned away from the container, with the ambient sensor detecting capacitance outside the container to compensate for ambient air effects, allowing for accurate fluid level measurements without direct contact or external coupling, and processors to determine fluid levels based on differential capacitance changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrodes are inserted into the fluid or coupled to the external surface to obtain accurate fluid level readings, then measurement precision is improved, but device complexity and ease of operation deteriorate due to installation difficulties and safety concerns
Solution Approach 1:
The patent uses the container wall as an intermediary medium to transmit the electric field from the sensor to the fluid. The sensor is positioned outside the container and uses the container wall (which the sensor can couple to) as a mediator to reach the fluid without direct contact, thus maintaining measurement accuracy while simplifying installation and eliminating safety concerns associated with inserting electrodes into volatile fluids
2Measurement precision
If electrodes are inserted into the fluid or coupled to the external surface to obtain accurate fluid level readings, then measurement precision is improved, but device complexity increases due to additional installation requirements and coupling mechanisms
Solution Approach 1:
The container wall serves as an intermediary that enables the sensor to measure fluid level without requiring complex installation mechanisms. The sensor couples to the container wall (a simple, standard component) rather than requiring direct coupling to the fluid or complex sealing mechanisms, thereby reducing overall system complexity while maintaining measurement precision
3Measurement precision
If ambient air capacitance effects are not compensated for, then device complexity is reduced, but measurement precision deteriorates due to inaccurate fluid level detection
Solution Approach 1:
The patent segments the capacitance measurement into two separate components: (1) the capacitance of the target zone containing the fluid, and (2) the capacitance of the ambient zone containing only air. By measuring these separately and calculating the difference, the system eliminates ambient air effects from the measurement, achieving high precision without requiring complex compensation algorithms or additional hardware beyond the two sensor zones
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
Enables convenient and accurate fluid level detection without the need for direct electrode insertion or external coupling, improving usability and reducing costs by normalizing capacitance measurements and triggering appropriate actions, such as disabling pumps when fluid levels reach thresholds.
Implementation Method 1
the target capacitance sensor being configured to generate a target electric field to detect a capacitance of a target zone comprising a target portion of the container's internal fluid volume
Implementation Method 2
the target capacitance sensor being configured to generate a target electric field
Implementation Method 3
the ambient capacitance sensor being configured to generate an ambient electric field to detect a capacitance of an ambient zone outside of the container
Implementation Method 4
the ambient capacitance sensor being configured to generate an ambient electric field
Implementation Method 5
capacitive fluid level sensors, which rely on the different dielectric properties of air and fluids in order to detect the presence or absence of fluid
Data Source
AI summary
A capacitive fluid level sensor is provided for receiving data indicative of the level of fluid remaining in a fluid container. In various embodiments, the capacitive fluid level sensor may be spaced below and a distance away from the fluid container to be measured, and may comprise a fluid level sensor and an ambient sensor, wherein the fluid level sensor and the ambient sensor are coplanar. In various embodiments, the ambient sensor may be spaced a distance away from the fluid level sensor, such that electric fields generated by the fluid level sensor and the ambient sensor, respectively, do not overlap. Based at least in part on capacitance levels determined by the fluid level sensor and the ambient sensor, the fluid level sensor may generate data indicative of the fluid level in at least a portion of the fluid container located above the fluid level sensor.