Detection of laundry coilers in laundry driers
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Solution Overview
Problem
Existing laundry drying devices struggle to reliably detect and prevent 'clothes winders' (entanglements) in rotating laundry drums, which affect drying efficiency and energy usage.
Innovation Solution
A method that records the time profile of electrical resistance during the drying process, transforms it into a frequency pattern, and monitors frequency peaks to detect changes, allowing for the identification of clothes winders, which can then trigger actions to improve drying efficiency and energy savings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electrical resistance measurement is used to detect laundry winders, then detection precision is improved, but device complexity increases due to signal processing requirements
Solution Approach 1:
The patent replaces complex mechanical sensor systems with an electrical resistance measurement system. Instead of using mechanical sensors to physically detect laundry entanglement, the system uses electrical resistance measurements combined with Fourier transformation to indirectly detect winder formation, thereby reducing mechanical complexity while maintaining detection precision
Solution Approach 2:
The patent transforms the resistance measurement from a time-domain signal to a frequency-domain signal using Fourier transformation. This parameter change in the signal domain allows for more precise detection of winder formation by analyzing frequency characteristics, while the transformation can be performed using standard processing algorithms rather than complex hardware
2Reliability
If Fourier transformation is applied to resistance signals, then detection reliability is improved, but processing time increases
Solution Approach 1:
The patent applies Fourier transformation at specific periodic intervals during the drying cycle rather than continuously. Resistance values are measured at regular time intervals and transformed into frequency patterns periodically, which maintains detection reliability by capturing winder formation events while avoiding the time penalty of continuous transformation
Solution Approach 2:
The system performs preliminary resistance measurements and stores the time profile data before conducting the Fourier transformation. This preliminary action allows the transformation to be performed on pre-collected data batches, reducing real-time processing delays while maintaining the ability to reliably detect winder formation
3Productivity
If monitoring frequency peaks is used to detect winders, then productivity is improved through faster detection, but measurement precision may be reduced compared to continuous monitoring
Solution Approach 1:
The patent introduces frequency peak positions as an intermediary parameter between raw resistance measurements and winder detection. Instead of directly analyzing complex resistance time profiles, the system extracts frequency peak positions from the transformed signal, which serve as simplified indicators of winder formation that can be monitored efficiently while retaining detection precision
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 a reliable, cost-effective, and precise detection of clothes winders, enabling energy savings and improved drying efficiency by differentiating winders from normal laundry through frequency analysis, independent of initial moisture content or air conditions.
Implementation Method 1
a resistance measuring device (3) for measuring an electrical resistance of the laundry (W)
Data Source
Figure 1
Figure 2A~2D
Figure 3A~3D
AI summary
A method serves to detect clothes winders in a clothes dryer (1) with a horizontally rotatable drum (2), wherein a time-dependent profile of the electrical resistance of laundry (W) located in the drum (2) is recorded while the drum (2) is rotating, the time-dependent profile is transformed into a frequency pattern (P1-P4), a time sequence of a frequency position (f1) of at least one frequency peak (P1) of the frequency pattern (P1-P4) is monitored, and then, when a frequency change (Δf) of the at least one monitored frequency position (P1) reaches at least a predetermined value (S), a conclusion is drawn that clothes winders of laundry (W) located in the drum (2) are present. A clothes dryer (1) is configured to carry out the method according to one of the preceding claims.