Capacitive Fill Level Sensor with Differential Housing Clearance
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Solution Overview
Problem
Current fill level measuring arrangements for fluids are costly and complex, with capacitive sensors being expensive and not suitable for universal applications due to the need for different sensor types for various viscosity media, leading to high variant numbers and increased costs.
Innovation Solution
A compact, cost-effective fill level measuring arrangement using two geometrically identical thin sensors arranged on a printed circuit board carrier element with evaluation electronics, where one sensor measures the dielectric constant of the medium directly and the other measures the air inside the housing, allowing for comparative measurements to deduce the fill level, with a housing design that minimizes construction complexity and power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different sensor types are used for various viscosity media (mechanical float switch for low-viscosity, capacitive sensor for high-viscosity), then the measurement functionality is adapted to the medium, but the number of variants increases and costs rise
Solution Approach 1:
The patent applies universality by designing a single capacitive sensor system that can measure fill level for both low-viscosity and high-viscosity media. The sensor is configured with two capacitive sensors at different clear distances from the housing wall, enabling it to function across different medium types without requiring multiple specialized sensor designs, thus reducing variant numbers while maintaining adaptability.
2Adaptability or versatility
If capacitive sensors are used for oil measurement, then universal electronic sensing is achieved, but the construction becomes more complex and costs increase with currently available sensors
Solution Approach 1:
The patent merges two capacitive sensors and the evaluation electronics onto a single printed circuit board carrier element. This integration simplifies the overall construction by combining multiple components into one unified structure, reducing the complexity that would otherwise result from using separate capacitive sensors and electronics housings.
Solution Approach 2:
The sensor elements are designed as thin plate-like structures mounted on the printed circuit board. This thin-film approach reduces the physical complexity and size of the sensor construction while maintaining the capacitive sensing functionality, making the universal sensor more compact and easier to install.
3Measurement precision
If standard capacitive sensors are used, then fill level measurement is achieved, but power consumption is higher compared to the optimized design
Solution Approach 1:
The evaluation electronics are designed to measure capacitance values periodically rather than continuously. The system takes capacitance measurements from both sensors at different clear distances, compares them, and deduces fill level at specific intervals. This periodic measurement approach maintains measurement precision while significantly reducing power consumption compared to continuous monitoring.
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 enables a universal, robust, and cost-effective capacitive fill level measurement for oils and greases, reducing power consumption and eliminating the need for exact frequency measurements, while maintaining full functionality and allowing for installation inside or outside the container with active shielding options.
Implementation Method 1
the fill level measuring arrangement having sensors (4, 5) which are designed to measure a capacitance
Implementation Method 2
the first sensor (4) to determine the dielectric constant of the medium to be measured almost directly, while the second sensor (5) comparatively measures the dielectric constant of a constant medium - this is usually the air inside the housing
Data Source
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AI summary
The invention relates to a fill level measurement system (1) for measuring the fill level (P) of a fluid (2) in a container (3), said fill level measurement system (1) having sensors (4, 5) that are designed to measure a capacity. In order to simplify the measurement, the invention provides that the fill level measurement system (1) has a housing (6) in which a first sensor (4) is arranged in a first height position (H1) and a second sensor (5) is arranged in a second height position (H2), both sensors (4, 5) being connected to an electronic evaluation unit (7) for measuring the respective capacities, a surface (8) of said first sensor (4) being at a first internal distance (s1) from a wall section (9) of the housing (6), a surface (10) of the second sensor (5) being at a second internal distance (s2) from a wall section (11) of the housing (6), and the second internal distance (s2) being larger than the first internal distance (s1).