Pressure-Based Fill Level Measurement for Liquid Food Containers
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Solution Overview
Problem
Existing fill level measuring devices for liquid food containers, such as those in coffee machines, face inaccuracies and high calibration demands, often detecting empty containers when there is still a significant amount of liquid remaining, due to reliance on capacitive resistance or weight measurement methods.
Innovation Solution
A fill level measuring device that uses a container pressure sensor to measure the liquid pressure within the container, determining the fill level by calculating the pressure difference between the liquid pressure and ambient pressure, which is either user-input or measured by an ambient pressure sensor, allowing for precise detection of liquid presence and level without the limitations of capacitive resistance or weight-based methods.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If capacitive resistance is used to monitor fill level, then the fill level can be detected, but the measurement is imprecise and high calibration demands are placed on the control system
Solution Approach 1:
The patent replaces capacitive resistance measurement with a pressure-based measurement system. A pressure sensor measures the pressure difference between the container interior and ambient environment, which directly correlates to liquid height via hydrostatic pressure principles. This mechanical/physical measurement approach eliminates the need for complex capacitive control systems while improving measurement precision.
Solution Approach 2:
The patent introduces a pressure sensor as an intermediary measurement device that indirectly measures fill level through pressure differential. Instead of directly measuring capacitive properties of the liquid, the system uses pressure as an intermediary parameter that is easier to measure accurately and less sensitive to calibration issues.
2Measurement precision
If weight measurement is used to determine fill level, then the fill level can be detected, but inaccuracies occur due to unknown empty container weight
Solution Approach 1:
The patent replaces weight-based measurement with pressure-based measurement. Instead of measuring the total weight of container plus liquid and subtracting an unknown empty weight, the system measures the pressure differential caused by the liquid column, which directly indicates fill level without requiring knowledge of container weight.
Solution Approach 2:
The patent changes the measurement parameter from weight to pressure differential. By measuring pressure difference between container interior and ambient environment, the system obtains a parameter that is directly proportional to liquid height and independent of container characteristics.
3Reliability
If capacitive resistance measurement is used, then fill level monitoring is possible, but an empty container is often detected even though there is still a considerable amount of liquid food in the container
Solution Approach 1:
The patent replaces capacitive measurement with pressure measurement to reliably detect true liquid presence. The pressure sensor measures the actual hydrostatic pressure from the liquid column, providing accurate information about liquid quantity without the false readings that occur with capacitive methods when liquid level is low or container geometry varies.
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 provides a more cost-effective and precise method for monitoring the fill level of liquid foodstuffs, ensuring accurate detection of remaining liquid quantities and preventing unnecessary replacements, while minimizing user input and avoiding measurement errors due to ambient pressure changes.
Implementation Method 1
the evaluation unit (3) is designed to determine the fill level of the liquid foodstuff in the container as a function of the pressure difference between the liquid pressure and an ambient pressure
Implementation Method 2
the ambient pressure sensor (6) arranged in such a way that the pressure in the area surrounding the container can be measured by means of the ambient pressure sensor (6)
Data Source
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AI summary
The invention relates to a level measuring device for measuring the level of liquid foodstuffs in a container, comprising a sensor unit and an evaluation unit, wherein the evaluation unit is connected to the sensor unit and is designed such that the evaluation unit determines the level of the liquid foodstuff in the container depending on the measurement signals of the sensor unit, wherein the sensor unit comprises a container pressure sensor, wherein the container pressure sensor can be brought into operative contact with the liquid foodstuff in the container for measuring the liquid pressure of the liquid foodstuff in the container, and the evaluation unit is designed such that it determines the level of the liquid foodstuff in the container depending on the difference between the measured liquid pressure and an ambient pressure.