Capacitive Water Level Sensing for Precise Washing Machine Fill Control
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Solution Overview
Problem
Conventional water level sensing apparatuses in washing machines have low durability and are inefficient due to mechanical operation and sensitivity to air pressure changes, leading to unnecessary water and energy consumption.
Innovation Solution
A water level sensing apparatus with a main body having inner and outer walls and inserted electrodes, utilizing a micro-computer to judge the water level through capacitance value variations, which improves precision and reduces energy consumption by accurately measuring water levels without structural modifications to the washing machine.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional mechanical water level sensing apparatus is used, then the structure is simple, but the durability is low due to repeated mechanical operation
Solution Approach 1:
The patent replaces the conventional mechanical water level sensing system with a capacitive sensing system. Instead of using a mechanical float and magnet assembly that undergoes repeated mechanical operation, the invention uses electrodes to detect water level through capacitance changes. This substitution of mechanical system with an electrical field-based system eliminates wear and tear from mechanical movement, thereby significantly improving durability while maintaining relatively simple device structure.
Solution Approach 2:
The patent utilizes the dielectric properties of water (hydraulic principle) to detect water level. The capacitive sensor detects changes in capacitance caused by the presence of water between electrodes at different heights. This hydraulic-based detection method avoids mechanical movement while providing reliable water level sensing, resolving the contradiction between durability and structural simplicity.
2Measurement precision
If conventional air pressure-based water level sensing is used, then the device is simple to operate, but the measurement precision is low due to sensitivity to air pressure changes and volume variations
Solution Approach 1:
The patent replaces air pressure-based mechanical sensing with an electrical capacitive sensing system. The capacitive electrodes directly measure water level through dielectric constant changes, eliminating the intermediate air pressure transmission mechanism. This substitution removes the sensitivity to air pressure changes and volume variations, thereby improving measurement precision while keeping the sensing system relatively simple.
Solution Approach 2:
The patent changes the sensing parameter from air pressure to capacitance. By measuring capacitance changes between electrodes instead of air pressure variations, the system achieves higher measurement precision. The capacitance value changes directly with water level position, providing a more precise and stable measurement that is not affected by air pressure fluctuations or hose volume changes.
3Loss of energy
If conventional water level sensing apparatus is used, then the structure is established, but unnecessary water and energy are consumed due to inaccurate water level detection
Solution Approach 1:
The patent replaces inaccurate mechanical water level sensing with precise capacitive sensing. The accurate detection of water level through capacitance changes enables precise control of water supply, preventing both over-filling and under-filling. This eliminates unnecessary water consumption and the energy required to pump and heat excess water, directly addressing the energy loss problem.
4Ease of manufacture
If mechanical water level sensing apparatus is used, then the manufacturing is simple, but the device has low durability and requires frequent maintenance
Solution Approach 1:
The patent replaces mechanical components with electrical capacitive sensors. The electrodes and control circuitry are simpler to manufacture than precision mechanical assemblies with floats, magnets, and moving parts. The solid-state capacitive sensing system has no moving parts, eliminating wear and tear, thereby improving durability while maintaining ease of manufacture through standardized electronic component production.
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 solution provides precise water level measurement, reducing unnecessary water supply and energy consumption while maintaining durability and ease of integration with existing washing machine structures.
Implementation Method 1
a micro-computer to judge a water level in the main body through variation of a capacitance value of the plurality of electrodes
Implementation Method 2
filled with water supplied to the inside of the inner wall, a plurality of electrodes inserted between the inner wall and the outer wall
Data Source
AI summary
A water level sensing apparatus which more precisely senses a level of supplied water, a water supply hose and a washing machine having the same is provided. The water level sensing apparatus includes a main body provided with an inner wall and an outer wall and filled with water supplied to the inside of the inner wall, a plurality of electrodes inserted between the inner wall and the outer wall to be opposite to each other, and a micro-computer to judge a water level in the main body through variation of a capacitance value of the plurality of electrodes. Therethrough, the water level sensing apparatus more directly measures a water level, as compared to the conventional water level sensing apparatus, thus improving precision in water level measurement. Thereby, the water level sensing apparatus prevents unnecessary water supply and reduces energy consumption.