Laundry appliance with capacitive laundry drying degree sensing function
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Solution Overview
Problem
Existing laundry drying appliances lack precision in measuring laundry mass humidity due to inaccurate impedance measurement methods, which are complex to implement and prone to errors, especially when the laundry is almost dry, and capacitive sensing solutions require cumbersome condenser arrangements.
Innovation Solution
A capacitive laundry mass drying degree sensing method using a capacitor with the laundry mass as dielectric, measured by electronic circuitry supplied with a supply voltage and reference voltage, allowing for accurate control of the drying process by determining capacitance and adjusting parameters such as drying air power, drum speed, and time duration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If laundry mass humidity is measured by electrical conductivity measurement, then humidity measurement function is provided, but measurement precision deteriorates when laundry is almost dry
Solution Approach 1:
The patent replaces the electrical conductivity measurement system with a capacitive sensing system. The capacitive sensor measures changes in capacitance caused by variations in the dielectric properties of the laundry mass, which are more sensitive to humidity changes, especially when the laundry is nearly dry. This substitution of measurement principle resolves the contradiction by providing reliable humidity measurement across the entire drying range.
Solution Approach 2:
The patent changes the measurement parameter from electrical conductivity to capacitance. By measuring capacitance rather than conductivity, the system can detect humidity levels more accurately, particularly in the low-humidity range when laundry is almost dry. The capacitive sensor detects changes in the dielectric constant of the laundry mass, which provides superior measurement precision across all humidity levels.
2Measurement precision
If condenser arrangement is used for capacitive sensing, then laundry humidity measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The patent makes the routing lines that are already present in the appliance serve dual functions: both their original function and as the second plate of the capacitive sensor. By utilizing existing conductive routing lines as part of the sensing mechanism, the system achieves accurate capacitive sensing without adding separate condenser plates or complex sensor structures, thereby maintaining measurement precision while minimizing device complexity.
Solution Approach 2:
The patent enables the routing lines to serve themselves by using their inherent conductivity and physical presence to function as the second plate of the capacitor. The existing structural elements of the appliance are repurposed as sensing components, eliminating the need for additional dedicated sensing structures and reducing overall system complexity while maintaining measurement accuracy.
3Ease of operation
If drying program time is predetermined, then appliance operation is simplified, but energy consumption increases
Solution Approach 1:
The patent implements a feedback mechanism where the capacitive sensor continuously monitors the humidity level of the laundry mass during the drying cycle. The control unit receives real-time capacitance measurements and adjusts the drying program parameters (such as heating power and drum speed) accordingly. This feedback control allows the system to maintain simple operation for the user while automatically optimizing energy consumption by adapting the drying process to the actual moisture content of the laundry.
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 method provides improved accuracy in determining laundry humidity and controlling the drying process, reducing energy consumption and ensuring optimal drying performance by accurately measuring capacitance and adjusting drying parameters in real-time.
Implementation Method 1
measuring a capacitance of the capacitor
Implementation Method 2
having, as part of the capacitor dielectric, the laundry mass
Data Source
AI summary
A method for measuring the humidity of a laundry mass contained in a laundry treatment chamber of a laundry appliance. The method includes: providing a capacitor in the laundry appliance, said capacitor having, as part of the capacitor dielectric, the laundry mass; measuring a capacitance of said capacitor by means of an electronic circuitry electrically supplied by a supply voltage and a reference voltage. Providing a capacitor comprises: providing in the laundry appliance at least one conductive plate which forms a plate of said capacitor, and exploiting, as a second plate of said capacitor, routing lines distributing inside the laundry drying appliance said reference voltage.