Level Detection System
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Solution Overview
Problem
Existing level detection systems for liquid in containers, such as coffee machines, are not suitable for removable tanks and degrade over time due to direct contact with water, especially when exposed to varying water hardness and splashes or steam, and require sensor components within the tank.
Innovation Solution
A level detection system using a capacitor with conductive plates positioned externally to the container, which determines the liquid level based on capacitance changes without direct contact, and includes reference capacitors to account for stray capacitance, allowing for accurate liquid level measurement without sensor degradation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If sensor components are located within the water tank to detect liquid level, then level detection can be performed, but the sensor performance degrades over time due to direct contact with water and exposure to steam
Solution Approach 1:
The sensor system is extracted from the water tank interior and relocated to the exterior housing. The capacitance sensor detects water level through the tank wall without direct contact with water, eliminating degradation from water hardness and steam exposure while maintaining detection functionality.
2Measurement precision
If optical sensors are used for level detection, then non-contact measurement is achieved, but the sensors are still exposed to splashes and fouling from steam
Solution Approach 1:
The tank wall acts as an intermediary medium between the external capacitance sensor and the water inside. The sensor measures capacitance through the non-conductive tank wall material, eliminating direct exposure to steam and splashes while maintaining accurate level detection capability.
3Device complexity
If capacitor plates are positioned parallel to each other, then the structure is simple, but the measurement may be affected by stray capacitance
Solution Approach 1:
The capacitor plates are positioned in a non-parallel arrangement where one plate is closer to the water surface than the other. This asymmetric configuration creates a capacitance gradient that improves measurement precision by reducing the impact of stray capacitance while maintaining structural simplicity.
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 system provides reliable and durable liquid level detection for removable containers by avoiding direct contact with the liquid and minimizing the impact of water hardness and steam exposure, ensuring consistent performance over time.
Implementation Method 1
a capacitor having a first plate and a second plate, the wall portions including a first wall portion having the first plate and a second wall portion having the second plate, such that when the container is in the receiving space, a capacitance of the capacitor depends on a level of substance in the container
Implementation Method 2
The capacitive dielectric constant between the plates would depend on the water level in the water tank, which would affect the capacitance value
Data Source
AI summary
There is disclosed herein a level detection system includes a housing (120) having a plurality of wall portions defining a receiving space for a container (200). The system further includes a capacitor having a first plate (142a) and a second plate (142b), the wall portions including a first wall portion having the first plate (142a) and a second wall portion having the second plate (142b). When the container is in the receiving space, a capacitance of the capacitor depends on a level of substance in the container (200). The system also includes a processor configured to determine the level of the substance in the container (200) based on the capacitance of the capacitor.