Houshold device with container and filling level measuring device and a corresponding procedure for measuring the filling level
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Solution Overview
Problem
Existing household appliances lack reliable methods to detect the fill level of detergent or washing aids in containers, leading to a risk of initiating a washing process without sufficient detergent, which can result in inefficient washing cycles and increased detergent consumption.
Innovation Solution
An electrical measuring device with two measuring electrodes and a circuit arrangement that applies an alternating voltage to measure conductance, allowing for accurate detection of the detergent level and preventing washing processes without sufficient detergent, using a microcontroller to manage the measurement and reduce component complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If an electrical measuring device with two measuring electrodes and circuit arrangement is used to measure conductance, then measurement precision of detergent level is improved, but device complexity increases
Solution Approach 1:
The patent replaces mechanical level sensing mechanisms with an electrical conductance measurement system. Two measuring electrodes are positioned at different heights in the container, and a circuit arrangement measures the conductance between them. When detergent reaches a certain level, it completes the electrical circuit between electrodes, providing precise level detection through electrical rather than mechanical means.
Solution Approach 2:
The patent utilizes changes in electrical conductance parameter to detect detergent level. The circuit arrangement applies an alternating voltage between measuring electrodes and detects changes in conductance caused by the presence or absence of detergent. This parameter change approach enables accurate level measurement without complex mechanical structures.
2Reliability
If alternating voltage is applied between measuring electrodes to measure conductance, then reliability of detergent detection is improved, but use of energy increases
Solution Approach 1:
The patent employs periodic application of alternating voltage between the measuring electrodes rather than continuous DC voltage. The circuit arrangement periodically switches the voltage on and off, measuring conductance during active periods and minimizing energy consumption during inactive periods. This periodic action maintains reliable detection capability while reducing overall energy usage.
Solution Approach 2:
The circuit arrangement incorporates feedback mechanisms to optimize energy usage. The system continuously monitors conductance between electrodes and adjusts its measurement activity based on detected conditions. When detergent is present and level is stable, the system can reduce measurement frequency, thereby lowering energy consumption while maintaining reliable detection of level changes.
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
Ensures reliable detection of the detergent level, preventing washing processes without detergent and optimizing detergent usage by signaling refill needs and transmitting information to the appliance's control unit, thereby minimizing waste and ensuring efficient washing cycles.
Implementation Method 1
The circuit arrangement can apply an AC voltage between the measuring electrodes and measure at least one measured variable correlated with the AC voltage and with a conductance of a medium located between the measuring electrodes
Implementation Method 2
By applying an alternating voltage to the measuring electrodes, galvanic effects on the measuring electrodes can be avoided
Data Source
Figure 1
Figure 2
Figure 3a~3b
AI summary
The invention relates to a domestic appliance having a container (1) which is intended to receive liquids and is set up, in particular, to store a detergent (2) and to automatically meter said detergent (2). An electrical measuring device (3) which measures a filling level of the storage container (1) is provided. The measuring device (3) has two measuring electrodes (10, 11), which are arranged at a distance from one another in the container (1), and a circuit arrangement (4) which is coupled to the measuring electrodes (10, 11) and is designed to apply an AC voltage (UR) between the measuring electrodes (10, 11) and to measure at least one measurement variable (UM1, UM2, UD) which is correlated with the AC voltage (UR) and with a conductance of a medium (2) between the measuring electrodes. The circuit arrangement (4) also has switching means (16, 17) which can be used to couple the measuring electrodes (10, 11) either to a first connection (12), to which a positive first potential (U1) is applied, or to a second connection (13), to which a positive second potential that is lower than the first potential or a potential (U2) of 0 volts is applied. The invention also relates to a corresponding filling level measuring method.